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2023, Vol. 80, No. 5　Online: 15 May 2023

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Unraveling abnormal buried interface anion defect passivation mechanisms depending on cation-induced steric hindrance for efficient and stable perovskite solar cells Dongmei He, Ru Li, Baibai Liu, Qian Zhou, Hua Yang, Xuemeng Yu, Shaokuan Gong, Xihan Chen, Baomin Xu, Shangfeng Yang, Jiangzhao Chen 2023, 80(5): 1-9.  DOI: 10.1016/j.jechem.2023.01.043 Abstract ( 20 )   PDF (2191KB) ( 21 )   Although ionic liquids (ILs) have been widely employed to heal the defects in perovskite solar cells (PSCs), the corresponding defect passivation mechanisms are not thoroughly understood up to now. Herein, we first reveal an abnormal buried interface anion defect passivation mechanism depending on cation-induced steric hindrance. The IL molecules containing the same anion ([BF4]-) and different sizes of imi-dazolium cations induced by substituent size are used to manipulate buried interface. It was revealed what passivated interfacial defects is mainly anions instead of cations. Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations, and facilitate the interaction between anions and SnO2 as well as perovskites, which is con-ducive to interfacial defect passivation and ameliorating interfacial contact. It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations. The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite. Compared with the control device (21.54%), the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate (BAIMBF4) with maximum size cations achieves a significantly enhanced efficiency of 23.61% along with much increased moisture, ther-mal and light stabilities.

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Highly reinforce the interface stability using 2-Phenyl-1H-imidazole-1-sulfonate electrolyte additive to enhance the high temperature performance of LiNi0.8Co0.1Mn0.1O2/graphite batteries Xin He, Yiting Li, Wenlian Wang, Xueyi Zeng, Huilin Hu, Haijia Li, Weizhen Fan, Chaojun Fan, Jian Cai, Zhen Ma, Junmin Nan 2023, 80(5): 10-22.  DOI: 10.1016/j.jechem.2023.01.042 Abstract ( 11 )   PDF (3791KB) ( 9 )   This work develops 2-Phenyl-1H-imidazole-1-sulfonate (PHIS) as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi0.8Co0.1Mn0.1O2/graphite batteries. After 450 cycles at room temperature (25 °C), the discharge capac-ity retentions of batteries with blank and PHIS-containing electrolyte are 56.03% and 94.92% respectively. After 230 cycles at high temperatures (45 °C), their values are 75.30% and 88.38% respectively. The enhanced electrochemical performance of the batteries with PHIS-containing electrolyte is supported by the spectroscopic characterization and theoretical calculations. It is demonstrated that this PHIS elec-trolyte additive can facilitate the construction of the electrode interface films, remove the H2O/HF in the electrolyte, and improve the electrochemical performance of the batteries. This work not only develops a sulfonate-based electrolyte but also can stimulate new ideas of functional additives to improve the bat-tery performance.

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Constructing the bonding between conductive agents and active materials/binders stabilizes silicon anode in Lithium-ion batteries Jie Tang, Jiawang Zhou, Xingyu Duan, Yujie Yang, Xinyi Dai, Fuzhong Wu 2023, 80(5): 23-31.  DOI: 10.1016/j.jechem.2023.01.035 Abstract ( 25 )   PDF (3239KB) ( 12 )   Silicon (Si) anode has been considered a promising candidate due to its remarkable theoretical capacity but it was plagued by severe pulverization because of the inherent huge volume variation. Enhancing electrode stability is an effective approach to improve electrochemical performance. Herein, a stable Si anode was established by an innovative construction of the bonding between conductive agents and active materials/binders. As a result, the strong interaction of electrode components not only effectively alleviates the volume expansion of Si but also achieves a stable interface by generating the beneficial solid electrolyte interphase (SEI) composition. Attributed to the deliberate scheme of the electrode, the Si anode exhibits sterling electrochemical performance. Besides, the device of the electrode is not only effective for other binders but also for other anode materials with high volume variation, thus shedding light on the rational design of electrodes for high-energy-density lithium-ion batteries.

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Anchoring polysulfide with artificial solid electrolyte interphase for dendrite-free and low N/P ratio Li-S batteries Wei Lu, Zhao Wang, Guiru Sun, Shumin Zhang, Lina Cong, Lin Lin, Siru Chen, Jia Liu, Haiming Xie, Yulong Liu 2023, 80(5): 32-39.  DOI: 10.1016/j.jechem.2023.01.032 Abstract ( 8 )   PDF (2233KB) ( 8 )   Lithium sulfur batteries are regarded as a promising candidate for high-energy-density energy storage devices. However, the lithium metal anode in lithium-sulfur batteries encounters the problem of lithium dendrites and lithium metal consumption caused by polysulfide corrosion. Herein we design a dual-function PMMA/PPC/LiNO3 composite as an artificial solid electrolyte interphase (PMCN-SEI) to protect Li metal anode. This SEI offers multiple sites of C@O for polysulfide anchoring to constrain corrosion of Li metal anode. The lithiated polymer group and Li3N in PMCN-SEI can homogenize lithium-ion deposi-tion behavior to achieve a dendrite-free anode. As a result, the PMCN-SEI protected Li metal anode enables the Li || Li symmetric batteries to maintain over 300 cycles (1300 h) at a capacity of 5 mA h cm-2, corresponding to a cumulative capacity of 3.25 Ah cm-2. Moreover, Li-S batteries assembled with 20 Lm of Li metal anode (N/P = 1.67) still deliver an initial capacity of 1166 mA h g-1 at 0.5C. Hence, introducing polycarbonate polymer/inorganic composite SEI on Li provides a new solution for achieving the high energy density of Li-S batteries.

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Simultaneous bottom-up double-layer synergistic engineering by multifunctional natural molecules for efficient and stable SnO2-based planar perovskite solar cells Yue Liu, Yanbo Gao, Tingting Li, Xinyu Bao, Zehua Xu, Fujun Zhang, Min Lu, Zhennan Wu, Yanjie Wu, Guang Sun, Xue Bai, Zhifeng Shi, Junhua Hu, Yu Zhang 2023, 80(5): 40-47.  DOI: 10.1016/j.jechem.2023.01.029 Abstract ( 10 )   PDF (1825KB) ( 6 )   The performance and stability of perovskite solar cells (PSCs) is limited by detrimental defects, mostly distributed at the grain boundary (GB) of bulk perovskite film and interface, which induce serious carrier non-radiative recombination. Therefore, there is particularly urgent to realize simultaneous passivation of bulk defects and interfacial defects. In this work, a simple, low-cost and effective multifunctional mod-ification strategy is developed by introducing the k-Carrageenan (k-C) as the interfacial layer of SnO2/per-ovskite. The sulfate groups of k-C not only play a positive role in passivating the Sn4+ from SnO2 film, resulting in high conductivity, but also effectively passivate the defects at the SnO2/perovskite interface. Meanwhile, k-C can effectively passivate the defects in the perovskite film due to the strong binding force between the high content of sulfate groups and PbI2. The synergistic effect of k-C simultaneously achieves interfacial defects and bulk defects passivation, better crystalline quality, suppressed charge recombina-tion, released interfacial stress and more favorable interfacial energy level alignment. Based on the above efficient synergy, the k-C-modified device achieves a high efficiency of 23.81%, which is ~24.53% higher than the control device (19.12%). To our best knowledge, 23.81% of power conversion efficiency (PCE) is the highest reported PCE value of PSCs employing green natural additives. Moreover, long-term and ther-mal stabilities are significantly improved after interface modification. Thus, this work provides an idea for developing multifunctional natural materials towards the attainment of the efficient and stable PSCs.

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Deep learning-based battery state of charge estimation: Enhancing estimation performance with unlabelled training samples Liang Ma, Tieling Zhang 2023, 80(5): 48-57.  DOI: 10.1016/j.jechem.2023.01.036 Abstract ( 15 )   PDF (2072KB) ( 6 )   The estimation of state of charge (SOC) using deep neural networks (DNN) generally requires a consider-able number of labelled samples for training, which refer to the current and voltage pieces with knowing their corresponding SOCs. However, the collection of labelled samples is costly and time-consuming. In contrast, the unlabelled training samples, which consist of the current and voltage data with unknown SOCs, are easy to obtain. In view of this, this paper proposes an improved DNN for SOC estimation by effectively using both a pool of unlabelled samples and a limited number of labelled samples. Besides the traditional supervised network, the proposed method uses an input reconstruction network to refor-mulate the time dependency features of the voltage and current. In this way, the developed network can extract useful information from the unlabelled samples. The proposed method is validated under differ-ent drive cycles and temperature conditions. The results reveal that the SOC estimation accuracy of the DNN trained with both labelled and unlabelled samples outperforms that of only using a limited number of labelled samples. In addition, when the dataset with reduced number of labelled samples to some extent is used to test the developed network, it is found that the proposed method performs well and is robust in producing the model outputs with the required accuracy when the unlabelled samples are involved in the model training. Furthermore, the proposed method is evaluated with different recurrent neural networks (RNNs) applied to the input reconstruction module. The results indicate that the pro-posed method is feasible for various RNN algorithms, and it could be flexibly applied to other conditions as required.

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An efficient electrocatalytic system composed of nickel oxide and nitroxyl radical for the oxidation of bio-platform molecules to dicarboxylic acids Kai Zhang, Zixiang Zhan, Minzhi Zhu, Haiwei Lai, Xiangyang He, Weiping Deng, Qinghong Zhang, Ye Wang 2023, 80(5): 58-67.  DOI: 10.1016/j.jechem.2023.01.039 Abstract ( 8 )   PDF (1575KB) ( 5 )   Selective oxidation of biomass and its derivatives to dicarboxylic acids represents a promising route for biomass valorization. However, the co-presence of multiple functional groups in biomass molecules makes the selective oxidation of particular functional a challenging task. Here, we demonstrate an effi-cient electrocatalytic system consisting of nickel oxide (NiO) and a nitroxyl radical, i.e., 2,2,6,6-tetrame thylpiperidine-1-oxyl (TEMPO) or 4-acetamido-TEMPO (ACT), for the selective oxidation of key bio-platform molecules including glucose, xylose and 5-hydroxymethylfurfural (HMF) into corresponding dicarboxylic acids, i.e., glucaric acid, xylaric acid, and 2,5-furandicarboxylic acid (FDCA). NiO is clarified as the active catalyst for the oxidation of aldehyde in bio-platform molecules to carboxylic acid, while TEMPO or ACT is responsible for the oxidation of primary alcohol to aldehyde. The combination of NiO and TEMPO or ACT significantly accelerated the tandem oxidation of aldehyde and hydroxyl groups in glucose, xylose and HMF, thus achieving excellent yields (83%-99%) of dicarboxylic acids. Moreover, the combination catalyst enables the selective oxidation of glucose and xylose with high concentrations (e.g., 20 wt%), which offers a promising strategy for biomass valorization.

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Mechanically flexible reduced graphene oxide/carbon composite films for high-performance quasi-solid-state lithium-ion capacitors Wenjie Liu, Yabin An, Lei Wang, Tao Hu, Chen Li, Yanan Xu, Kai Wang, Xianzhong Sun, Haitao Zhang, Xiong Zhang, Yanwei Ma 2023, 80(5): 68-76.  DOI: 10.1016/j.jechem.2023.01.031 Abstract ( 8 )   PDF (1793KB) ( 2 )   Practical applications of diverse flexible wearable electronics require electrochemical energy storage (EES) devices with multiple configurations. Moreover, to fabricate flexible EES devices with high energy density and stability, organic integration from electrode design to device assembly is required. To address these challenges, a free-standing reduced graphene oxide (rGO)/carbon film with a unique sandwich structure has been designed via the assistance of vacuum-assistant filtration for lithium-ion capacitors (LICs). The graphene acts as not only a binder to construct a three-dimensional conductive network but also an active material to provide additional capacitive lithium storage sites, thus enabling fast ion/electron transport and improving the capacity. The designed rGO/hard carbon (rGO/HC) and rGO/ activated carbon (rGO/AC) free-standing films exhibit enhanced specific capacities (513.7 mA h g-1 for rGO/HC and 102.8 mA h g-1 for rGO/AC) and excellent stability. Moreover, the integrated flexible quasi-solid-state rGO/AC//rGO/HC LIC devices possess a maximum energy density of 138.3 Wh kg-1, a high power density of 11 kW kg-1, and improved cycling performance (84.4% capacitance maintained after 10,000 cycles), superior to the AC//HC LIC (43.5% retention). Such a strategy enlightens the develop-ment of portable flexible LICs.

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Dendritic nanoarchitecture imparts ZSM-5 zeolite with enhanced adsorption and catalytic performance in energy applications María del Mar Alonso-Doncel, Cristina Ochoa-Hernández, Gema Gómez-Pozuelo, Adriana Oliveira, José González-Aguilar, Ángel Peral, Raúl Sanz, David P. Serrano 2023, 80(5): 77-88.  DOI: 10.1016/j.jechem.2023.01.023 Abstract ( 9 )   PDF (1632KB) ( 4 )   The development of zeolites possessing dendritic features represents a great opportunity for the design of novel materials with applications in a large variety of fields and, in particular, in the energy sector to afford its transition towards a low carbon system. In the current work, ZSM-5 zeolite showing a dendritic 3D nanoarchitecture has been synthesized by the functionalization of protozeolitic nanounits with an amphiphilic organosilane, which provokes the branched aggregative growth of zeolite embryos. Dendritic ZSM-5 exhibits outstanding accessibility arising from a highly interconnected network of radially-oriented mesopores (3 -10 nm) and large cavities (20 -80 nm), which add to the zeolitic micro-pores, thus showing a well-defined trimodal pore size distribution. These singular features provide den-dritic ZSM-5 with sharply enhanced performance in comparison with nano-and hierarchical reference materials when tested in a number of energy related applications, such as VOCs (toluene) adsorption (im-proved capacity), plastics (low-density polyethylene) catalytic cracking (boosted activity) and hydrogen production by methane catalytic decomposition (higher activity and deactivation resistance).

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In-situ constructed SnO2 gradient buffer layer as a tight and robust interphase toward Li metal anodes in LATP solid state batteries Lifan Wang, Leiying Wang, Qinlin Shi, Cong Zhong, Danya Gong, Xindong Wang, Chun Zhan, Guicheng Liu 2023, 80(5): 89-98.  DOI: 10.1016/j.jechem.2023.01.040 Abstract ( 10 )   PDF (3692KB) ( 7 )   Li1.3Al0.3Ti1.7(PO4)3 (LATP), of much interest owing to its high ionic conductivity, superior air stability, and low cost, has been regarded as one of the most promising solid-state electrolytes for next-generation solid-state lithium batteries (SSLBs). Unfortunately, the commercialization of SSLBs is still impeded by severe interfacial issues, such as high interfacial impedance and poor chemical stability. Herein, we pro-posed a simple and convenient in-situ approach to constructing a tight and robust interface between the Li anode and LATP electrolyte via a SnO2 gradient buffer layer. It is firmly attached to the surface of LATP pellets due to the volume expansion of SnO2 when in-situ reacting with Li metal, and thus effectively alle-viates the physical contact loosening during cycling, as confirmed by the mitigated impedance rising. Meanwhile, the as-formed SnO2/Sn/LixSn gradient buffer layer with low electronic conductivity success-fully protects the LATP electrolyte surface from erosion by the Li metal anode. Additionally, the LixSn alloy formed at the Li surface can effectively regulate uniform lithium deposition and suppress Li dendrite growth. Therefore, this work paves a new way to simultaneously address the chemical instability and poor physical contact of LATP with Li metal in developing low-cost and highly stable SSLBs.

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Micropore engineering on hollow nanospheres for ultra-stable sodium-selenium batteries Gongke Wang, Yumeng Chen, Yu Han, Lixue Yang, Wenqing Zhao, Changrui Chen, Zihao Zeng, Shuya Lei, Shaohui Yuan, Peng Ge 2023, 80(5): 99-109.  DOI: 10.1016/j.jechem.2022.12.054 Abstract ( 6 )   PDF (3259KB) ( 4 )   Attracted by high energy density and considerable conductivity of selenium (Se), Na-Se batteries have been deemed promising energy-storage systems. But, it still suffers from sluggish kinetic behaviors and similar ‘‘shuttling effect” to S-electrodes. Herein, utilizing uniform hollow carbon spheres as precur-sors, Se-material is effectively loaded through vapor-infiltration method. Owing to the distribution of optimized pores, the content of microspores could be up to ~60% (<2 nm), serving important roles for the physical confinement effect. Meanwhile, the rich oxygen-containing groups and N-elements could be noted, inducing the evolution of electron-moving behaviors. More significantly, assisted by the inter-facial C-Se bonds and tiny Se distributions, Se electrodes are activated during cycling. Used as cathodes for Na-Se systems, the as-resulted samples display a capacity of 593.9 mA h g-1 after 100 cycles at the current density of 0.1 C. Even after 6000 cycles, the capacity could be still kept at about 225 mA h g-1 at 5.0 C. Supported by the detailed kinetic analysis, the designed microspores size induces the increasing redox reaction of nano Se, whilst the surface traits further render the enhancement of pseudo-capacitive contributions. Moreover, after cycling, the product Sex (x < 4) in pores serves as the primary active mate-rial. Given this, the work is anticipated to provide an effective strategy for advanced electrodes for Na-Se systems.

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Ion dynamics into different pore size distributions in supercapacitors under compression João Pedro Aguiar dos Santos, Cesar J. B. Pagan, Rafael Vicentini, Reinaldo F. Teófilo, Renato Beraldo, Leonardo M. Da Silva, Hudson Zanin 2023, 80(5): 110-119.  DOI: 10.1016/j.jechem.2022.12.063 Abstract ( 11 )   PDF (2542KB) ( 3 )   Compressing supercapacitor (SCs) electrode is essential for improving the energy storage characteristics and minimizing ions' distance travel, faradaic reactions, and overall ohmic resistance. Studies comprising the ion dynamics in SC electrodes under compression are still rare. So, the ionic dynamics of five aqueous electrolytes in electrodes under compression were studied in this work for tracking electrochemical and structural changes under mechanical stress. A superionic state is formed when the electrode is com-pressed until the micropores match the dimensions with the electrolyte's hydrated ion sizes, which increases the capacitance. If excessive compression is applied, the accessible pore regions decrease, and the capacitance drops. Hence, as the studied hydrated ions have different dimensions, the match between ion/pore sizes differs. To the LiOH and NaClO4 electrolytes, increasing the pressure from 60 to 120 and 100 PSI raised the capacitance from 13.5 to 35.2 F g-1 and 30.9 to 39.0 F g-1, respectively. So, the KOH electrolyte with the lowest and LiCl with the biggest combination of hydrated ion size have their point of maximum capacitance (39.5 and 36.7F g-1) achieved at 140 and 80 PSI, respectively. To LiCl and KCl electrolytes, overcompression causes a drop in capacitance higher than 23%.

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Effect of N-doping-derived solvent adsorption on electrochemical double layer structure and performance of porous carbon Zhe-Fan Wang, Cheng Tang, Qian Sun, Ya-Lu Han, Zhi-Jian Wang, Lijing Xie, Shou-Chun Zhang, Fang-Yuan Su, Cheng-Meng Chen 2023, 80(5): 120-127.  DOI: 10.1016/j.jechem.2022.12.061 Abstract ( 9 )   PDF (1771KB) ( 5 )   N-doped porous carbon has been extensively investigated for broad electrochemical applications. The performance is significantly impacted by the electrochemical double layer (EDL), which is material dependent and hard to characterize. Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials. Thus, we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance, in-situ X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane (IHP), which prevents ion rearrangement and enhances the migration of cations. However, this specific adsorption accelerated solvent decomposition, rendering rapid performance degradation in practical devices. This work reveals that the surface chemistry of elec-trodes can cause specific adsorption of solvents and change the EDL structure, which complements the classical EDL theory and provide guidance for practical applications.

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Engineering hollow core-shell hetero-structure box to induce interfacial charge modulation for promoting bidirectional sulfur conversion in lithium-sulfur batteries Weiliang Zhou, Xinying Wang, Jiongwei Shan, Liguo Yue, Dongzhen Lu, Li Chen, Jiacheng Zhang, Yunyong Li 2023, 80(5): 128-139.  DOI: 10.1016/j.jechem.2023.01.038 Abstract ( 8 )   PDF (3051KB) ( 2 )   Severe polysulfide shuttling and sluggish sulfur redox kinetics significantly decrease sulfur utilization and cycling stability in lithium-sulfur batteries (LSBs). Herein, we develop a hollow CoO/CoP-Box core-shell heterostructure as a model and multifunctional catalyst modified on separators to induce interfacial charge modulation and expose more active sites for promoting the adsorption and catalytic conversion ability of sulfur species. Theoretical and experimental findings verify that the in-situ formed core-shell hetero-interface induces the formation of P-Co-O binding and charge redistribution to activate surface O active sites for binding lithium polysulfides (LiPSs) via strong Li-O bonding, thus strongly adsorbing with LiPSs. Meanwhile, the strong Li-O bonding weakens the competing Li-S bonding in LiPSs or Li2S adsorbed on CoO/CoP-Box surface, plus the hollow heterostructure provides abundant active sites and fast electron/Li+ transfer, so reducing Li2S nucleation/dissolution activation energy. As expected, LSBs with CoO/CoP-Box modified separator and traditional sulfur/carbon black cathode display a large initial capacity of 1240 mA h g-1 and a long cycling stability with 300 cycles ( 60.1% capacity retention) at 0.5C. Impressively, the thick sulfur cathode (sulfur loading: 5.2 mg cm-2) displays a high initial areal capacity of 6.9 mA h cm-2. This work verifies a deep mechanism understanding and an effective strategy to induce interfacial charge modulation and enhance active sites for designing efficient dual-directional Li-S cata-lysts via engineering hollow core-shell hetero-structure.

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Electro-enzyme coupling systems for selective reduction of CO2 Yuman Guo, Xueming Hong, Ziman Chen, Yongqin Lv 2023, 80(5): 140-162.  DOI: 10.1016/j.jechem.2023.01.041 Abstract ( 15 )   PDF (4267KB) ( 4 )   To address the energy crisis and alleviate the rising level of CO2 in the atmosphere, various CO2 capture and utilization (CCU) technologies have been developed. The use of electro-enzyme coupling systems is a promis-ing strategy for the sustainable production of fuels, chemicals and materials using CO2 as the feedstock. In this review, the recent progresses in the development of electro-enzyme coupling systems for the selective reduc-tion of CO2 are systematically summarized. We first provide a brief background about the significance and challenges in the direct conversion of CO2 into value-added chemicals. Next, we describe the materials and strategies in the design of electrodes, as well as the common enzymes used in the electro-enzyme cou-pling systems. Then, we focus on the state-of-the-art routes for the electro-enzyme coupling conversion of CO2 into a variety of compounds (formate, CO, methanol, C chemicals) by a single enzyme or multienzyme Electrochemistry Enzyme Electron transfer systems. The emerging approaches and materials used for the construction of electro-enzyme coupling sys-tems to enhance the electron transfer efficiency and the catalytic activity/stability are highlighted. The main challenges and perspectives in the integration of enzymatic and electrochemical strategies are also discussed.

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Phase separation-hydrogen etching-derived Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies boosting superior sodium-ion storage kinetics Lin Yan, Lingshuo Zong, Qi Sun, Junpeng Guo, Zhenyang Yu, Zhijun Qiao, Jiuhui Han, Zhenyu Cui, Jianli Kang 2023, 80(5): 163-173.  DOI: 10.1016/j.jechem.2023.01.045 Abstract ( 10 )   PDF (3546KB) ( 5 )   Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms. Herein, an integrated self-supporting anode of the Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies (Ov-BMO-Cu) are in-situ generated by phase separation and hydrogen etching using nanoporous Cu-Mn alloy as self-sacrificial templates. On this basis, we have elucidated the relationship between the phase evolution, oxy-gen vacancies and sodium-ion storage mechanisms, further demonstrating the evolution of oxygen vacancies and the inhibition effect of manganese oxides as an ‘‘anchor” on grain aggregation of copper oxides. The kinetic analyses confirm that the expanded lattice space and increased oxygen vacancies of cycled Ov-BMO-Cu synergistically guarantee effective sodium-ion diffusion and storage mechanisms. Therefore, the Ov-BMO-Cu electrode exhibits higher reversible capacities of 4.04 mA h cm-2 at 0.2 mA cm-2 after 100 cycles and 2.20 mA h cm-2 at 1.0 mA cm-2 after 500 cycles. Besides, the pre-sodiated Ov-BMO-Cu anode delivers a considerable reversible capacity of 0.79 mA h cm-2 at 1.0 mA cm-2 after 60 cycles in full cells with Na3V2(PO4)3 cathode, confirming its outstanding practicality. Thus, this work is expected to provide enlightenment for designing high-capacity bimetallic oxide anodes.

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Stepwise optimization of single-ion conducting polymer electrolytes for high-performance lithium-metal batteries Xu Dong, Zhen Chen, Xinpei Gao, Alexander Mayer, Hai-Peng Liang, Stefano Passerini, Dominic Bresser 2023, 80(5): 174-181.  DOI: 10.1016/j.jechem.2023.01.044 Abstract ( 5 )   PDF (1223KB) ( 4 )   Single-ion conducting polymer electrolytes (SIPEs) are promising candidates for high-energy and high-safety lithium-metal batteries (LMBs). However, their insufficient ionic conductivity and electrochemical stability hinder their practical application. Herein, three new SIPEs, i.e., poly (1,4-phenylene ether ether sulfone)-Li (PEES-Li), polysulfone-Li (PSF-Li), and hexafluoropolysulfone-Li (6FPSF-Li), all containing covalently tethered perfluorinated ionic side chains, have been designed, synthesized, and compared to investigate the influence of the backbone chemistry and the concentration of the ionic group on their electrochemical properties and cell performance. Especially, the trifluoromethyl group in the backbone and the concentration of the ionic function appear to play an essential role for the charge transport and stability towards oxidation, and the combination of both yields the best-performing SIPE with high ionic conductivity of ca. 2.5 × 10-4 S cm-1, anodic stability of more than 4.8 V, and the by far highest Lithium-metal battery capacity retention in Li LiNi0.6Co0.2Mn0.2O2 cells.

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Methanation of CO/CO2 for power to methane process: Fundamentals, status, and perspectives Jie Ren, Hao Lou, Nuo Xu, Feng Zeng, Gang Pei, Zhandong Wang 2023, 80(5): 182-206.  DOI: 10.1016/j.jechem.2023.01.034 Abstract ( 13 )   PDF (7367KB) ( 7 )   Power-to-methane (P2M) processes, by converting electricity from renewable energy to H2 and then into other high value-added and energy-intense chemicals in the presence of active catalysts, have become an effective solution for energy storage. However, the fluctuating electricity from intermittent renewable energy leads to a dynamic composition of reactants for downstream methanation, which requires an excellent heterogeneous catalyst to withstand the harsh conditions. Based on these findings, the objective of this review is to classify the fundamentals and status of CO/CO2 methanation and identify the path-ways in the presence of various catalysts for methane production. In addition, this review sheds insight into the future development and challenges of CO2 or CO methanation, including the deactivation mech-anisms and catalyst performance under dynamically harsh conditions. Finally, we elaborated on the advantages and development prospects of P2M, and then we summarized the current stage and ongoing industrialization projects of P2M.

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In-situ construction of high-mechanical-strength and fast-ion-conductivity interphase for anode-free Li battery Yangfan Lin, Juner Chen, Han Zhang, Jianhui Wang 2023, 80(5): 207-214.  DOI: 10.1016/j.jechem.2023.02.005 Abstract ( 8 )   PDF (2126KB) ( 6 )   The solid electrolyte interphase (SEI) with strong mechanical strength and high ion conductivity is highly desired for Li metal batteries, especially for harsh anode-free batteries. Herein, we report a pragmatic approach to the in-situ construction of high-quality SEI by applying synergistic additives of LiNO3 and ethylene sulfite (ES) in the electrolyte. The obtained SEI exhibits a high average Young's modulus (9.02 GPa) and exchanging current density (4.59 mA cm-2), which are 3.0 and 1.2 times as large as those using the sole additive of LiNO3, respectively. With this improved SEI, Li-dendrite growth and side reactions are effectively suppressed, leading to an ultra-high Coulombic efficiency (CE) of 99.7% for Li plating and strip-ping. When applying this improved electrolyte in full cells, it achieves a high capacity retention of 89.7% for over 150 cycles in a LiFePO4||Li battery (~12 mg cm-2 cathode, 50 lm Li) and of 44.5% over 100 cycles in a LiFePO4||Cu anode-free battery.

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High H2 selective performance of Ni-Fe-Ca/H-Al catalysts for steam reforming of biomass and plastic Jin Deng, Lingshuai Meng, Duo Ma, Yujie Zhou, Xianyang Wang, Xiaodong Luo, Shenfu Yuan 2023, 80(5): 215-227.  DOI: 10.1016/j.jechem.2023.02.001 Abstract ( 6 )   PDF (3577KB) ( 2 )   The development of a selective catalyst for the conversion of biomass and plastics into H2 by steam reforming can combat the energy crisis and global warming. In this work, support Ni-Fe-Ca/H-Al bifunc-tional catalysts were prepared by loading Ni and Fe into pretreatment CaO/Al2O3 (Ca/H-Al) carriers and showed high catalytic activity for the steam reforming of biomass and plastic. Moreover, the idea of bidi-rectional degradation was exploited to strengthen the pyrolysis of plastic with a high H/C and biomass with a high O/C. Interestingly, the products presented high H2 selective (1302.10 mL/g) and low CO2 yield (120.23 mL/g) in 7Ni-5Fe-Ca/H-Al(2:4) catalyst compared with current reports. Here, the abundant oxy-gen vacancies (Ov) in the H-Al carrier exhibited an electron-deficient nature, providing active sites for anchoring NiO. Meanwhile, NiO interacted with Ca2Fe2O5 to produce more defective Ov sites, which sta-bilized the NiO particles in the 7Ni-5Fe-Ca/H-Al (2:4) catalyst, and the interaction between the catalyst and the carrier was enhanced, leading to the reduction of weakly basic sites, this property promoted the strong adsorption of CO2 and H2O by the catalyst, contributing to the enhancement of efficient steam con-version and the promotion of conversion of by-products to H2. Notably, 7Ni-5Fe-Ca/H-Al(2:4) catalysts maintained structural integrity after regeneration and exhibited excellent regenerability in H2 selection and CO2 adsorption. The work provides a new idea for the study of efficient H2 production from steam reforming of biomass and plastics.

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Spatiotemporal phase change materials for thermal energy long-term storage and controllable release Yangeng Li, Yan Kou, Keyan Sun, Jie Chen, Chengxin Deng, Chaohe Fang, Quan Shi 2023, 80(5): 228-236.  DOI: 10.1016/j.jechem.2023.01.052 Abstract ( 12 )   PDF (1793KB) ( 10 )   Phase change materials (PCMs) have attracted much attention in the field of solar thermal utilization recently, due to their outstanding thermal energy storage performance. However, PCMs usually release their stored latent heat spontaneously as the temperature below the phase transition temperature, ren-dering thermal energy storage and release uncontrollable, thus hindering their practical application in time and space. Herein, we developed erythritol/sodium carboxymethylcellulose/tetrasodium ethylene-diaminetetraacetate (ERY/CMC/EDTA-4Na) composite PCMs with novel spatiotemporal thermal energy storage properties, defined as spatiotemporal PCMs (STPCMs), which exhibit the capacity of thermal energy long-term storage and controllable release. Our results show that the composite PCMs are unable to lose latent heat due to spontaneous crystallization during cooling, but can controllably release thermal energy through cold crystallization during reheating. The cold-crystallization temperature and enthalpy of composite PCMs can be adjusted by proportional addition of EDTA-4Na to the composite. When the mass fractions of CMC and EDTA-4Na are both 10%, the composite PCMs can exhibit the optical cold-crystallization temperature of 51.7 °C and enthalpy of 178.1 J/g. The supercooled composite PCMs with-out latent heat release can be maintained at room temperature (10-25 °C) for up to more than two months, and subsequently the stored latent heat can be controllably released by means of thermal trig-gering or heterogeneous nucleation. Our findings provide novel insights into the design and construction of new PCMs with spatiotemporal performance of thermal energy long-term storage and controllable release, and consequently open a new door for the development of advanced solar thermal utilization techniques on the basis of STPCMs.

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Investigation of multi-step fast charging protocol and aging mechanism for commercial NMC/graphite lithium-ion batteries Yaqi Li, Jia Guo, Kjeld Pedersen, Leonid Gurevich, Daniel-Ioan Stroe 2023, 80(5): 237-246.  DOI: 10.1016/j.jechem.2023.01.016 Abstract ( 12 )   PDF (2817KB) ( 9 )   Fast charging is considered a promising protocol for raising the charging efficiency of electric vehicles. However, high currents applied to Lithium-ion (Li-ion) batteries inevitably accelerate the degradation and shorten their lifetime. This work designs a multi-step fast-charging method to extend the lifetime of LiNi0.5Co0.2Mn0.3O2 (NMC)/graphite Li-ion batteries based on the studies of half cells and investigates the aging mechanisms for different charging methods. The degradation has been studied from both full cell behaviour and materials perspectives through a combination of non-destructive diagnostic methods and post-mortem analysis. In the proposed multi-step charging protocol, the state-of-charge (SOC) profile is subdivided into five ranges, and the charging current is set differently for different SOC ranges. One of the designed multi-step fast charging protocols is shown to allow for a 200 full equivalent cycles longer lifetime as compared to the standard charging method, while the charging time is reduced by 20%. From the incremental capacity analysis and electrical impedance spectroscopy, the loss of active materials and lithium inventory on the electrodes, as well as an increase in internal resistance for the designed multi-step constant-current-constant-voltage (MCCCV) protocol have been found to be significantly lower than for the standard charging method. Post-mortem analysis shows that cells aged by the designed MCCCV fast charging protocol exhibit less graphite exfoliation and crystallization damage, as well as a reduced solid electrolyte interphase (SEI) layer growth on the anode, leading to a lower Rsei resistance and extended lifetime.

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Electronically modulated d-band centers of MOF-derived carbon-supported Ru/HfO2 for oxygen reduction and aqueous/flexible zinc-air batteries Chuan Hu, Fengli Wei, Qinrui Liang, Qiming Peng, Yuting Yang, Tayirjan Taylor Isimjan, Xiulin Yang 2023, 80(5): 247-255.  DOI: 10.1016/j.jechem.2023.01.047 Abstract ( 5 )   PDF (2267KB) ( 4 )   The construction of oxide/metal composite catalysts is a competent means of exploiting the electronic interactions between oxide/metal to enhance catalytic activity. In this work, we construct a novel hetero-geneous composite (Ru/HfO2-NC) with Ru/HfO2 nanoparticles nested in nitrogen-doped porous carbon via a zeolitic imidazole frameworks-assisted (ZIF) co-precipitation and calcination approach. In particu-lar, ZIF guides an in-situ construction of nested configuration and confines the scattered nanoparticles. Strikingly, Ru/HfO2-NC exhibits unusual ORR activity, superb durability, and methanol tolerance in 0.1 M KOH solution with high half-wave potential (E1/2) of 0.83 V and follows a near-4e- reaction path-way. Additionally, the ZAB assembled with cathodic Ru/HfO2-NC outputs a power density of 157.3 mW cm-2, a specific capacity of 775 mA h g-1, and a prolonged lifespan of 258 h at 5 mA cm-2. Meanwhile, the catalyst has demonstrated potential applicability in flexible ZAB. As suggested by experimental results and density functional theory (DFT) analysis, the remarkable property possibly originated from the opti-mization of the adsorption and desorption of reactive intermediates caused by the reconfiguration of the electronic structure between Ru and HfO2.

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Back contact interfacial modification mechanism in highly-efficient antimony selenide thin-film solar cells Junhui Lin, Guojie Chen, Nafees Ahmad, Muhammad Ishaq, Shuo Chen, Zhenghua Su, Ping Fan, Xianghua Zhang, Yi Zhang, Guangxing Liang 2023, 80(5): 256-264.  DOI: 10.1016/j.jechem.2023.01.049 Abstract ( 13 )   PDF (2196KB) ( 4 )   Antimony selenide (Sb2Se3) is a potential photovoltaic (PV) material for next-generation solar cells and has achieved great development in the last several years. The properties of Sb2Se3 absorber and back con-tact influence the PV performances of Sb2Se3 solar cells. Hence, optimization of back contact character-istics and absorber orientation are crucial steps in raising the power conversion efficiency (PCE) of Sb2Se3 solar cells. In this work, MoO2 was introduced as an intermediate layer (IL) in Sb2Se3 solar cells, and comparative investigations were conducted. The growth of (211)-oriented Sb2Se3 with large grains was facilitated by introducing the MoO2 IL with suitable thickness. The MoO2 IL substantially lowered the back contact barrier and prevented the formation of voids at the back contact, which reduced the thickness of the MoSe2 interface layer, inhibited carrier recombination, and minimized bulk and interfa-cial defects in devices. Subsequently, significant optimization enhanced the open-circuit voltage (VOC) of solar cells from 0.481 V to 0.487 V, short-circuit current density (JSC) from 23.81 mA/cm2 to 29.29 mA/ cm2, and fill factor from 50.28% to 57.10%, which boosted the PCE from 5.75% to 8.14%.

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Best practices for electrochemical characterization of supercapacitors João Pedro Aguiar dos Santos, Fernando Cesar Rufino, João I. Yutaka Ota, Rodolfo C. Fernandes, Rafael Vicentini, Cesar J.B. Pagan, Leonardo Morais Da Silva, Hudson Zanin 2023, 80(5): 265-283.  DOI: 10.1016/j.jechem.2022.12.034 Abstract ( 15 )   PDF (3073KB) ( 8 )   We discuss here essential aspects of the experimental supercapacitors characterization by a series of well-known electrochemical methods. We are motivated by a considerable number of publications that misreport procedures and results. Authors often conceal or neglect essential information about the elec-trochemical analytical apparatus used and its configuration. The lack of such information may lead researchers, especially inexperienced ones, to misunderstand the procedures and results. Eventually, the misled electrochemical equipment configuration favors misinterpretation of data and low repro-ducibility rates. This paper aims to highlight these issues and clarify them. We explain fundamental con-cepts of some electrochemical analytical methods, such as cyclic voltammetry, galvanostatic charge-discharge, single potential step chronoamperometry, and electrochemical impedance spectroscopy, focusing on the supercapacitor field. Distinct configurations of electrical parameters are presented and discussed to highlight the effects of incorrect setup and uncover misleading results. We discuss how the electrochemical setup and data analyses matter in reliable data results for the supercapacitor.

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Directing in-situ self-optimization of single-atom catalysts for improved oxygen evolution Peiyu Ma, Chen Feng, Huihuang Chen, Jiawei Xue, Xinlong Ma, Heng Cao, Dongdi Wang, Ming Zuo, Ruyang Wang, Xilan Ding, Shiming Zhou, Zhirong Zhang, Jie Zeng, Jun Bao 2023, 80(5): 284-290.  DOI: 10.1016/j.jechem.2022.12.051 Abstract ( 6 )   PDF (2097KB) ( 5 )   The demand for clean and sustainable energy has encouraged the production of hydrogen from water electrolyzers. To overcome the obstacle to improving the efficiency of water electrolyzers, it is highly desired to fabricate active electrocatalysts for the sluggish oxygen evolution process. However, there is generally an intrinsic gap between the as-prepared and real electrocatalysts due to structure evolution under the oxidative reaction conditions. Here, we combine in-situ anionic leaching and atomic deposition to realize single-atom catalysts with self-optimized structures. The introduced F ions facilitate structural transformation from Co(OH)xF into CoOOH(F), which generates an amorphous edge surface to provide more anchoring sites for Ir single atoms. Meanwhile, the in-situ anionic leaching of F ions elevates the Co valence state of Ir1/CoOOH(F) more significantly than the counterpart without F ions (Ir1/CoOOH), leading to stronger adsorption of oxygenated intermediates. As revealed by electrochemical measure-ments, the increased Ir loading together with the favored adsorption of *OH intermediates improve the catalytic activity of Ir1/CoOOH(F). Specifically, Ir1/CoOOH(F) delivered a current density of 10 mA cm-2 at an overpotential of 238 mV, being lower than 314 mV for Ir1/CoOOH. The results demonstrated the facility of the in-situ optimization process to optimize catalyst structure for improved performance.

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Hierarchically designed MoWSe2/WO3/C anode for fast and efficient Na+ storage Jian Wang, Yachuan Shao, Fei Yuan, Huilan Sun, Di Zhang, Zhaojin Li, S. Ramesh, H.J. Woo, Bo Wang 2023, 80(5): 291-301.  DOI: 10.1016/j.jechem.2023.01.024 Abstract ( 12 )   PDF (3609KB) ( 3 )   Exploring anode materials with high energy and power density is one of the critical milestones in devel-oping sodium-ion batteries/capacitors (SIBs/SICs). Here, the Mo and W-based bimetallic organic frame-work (Mo-W-MOF) with core-shell structure is first formed by a facile strategy, followed by a selenization and carbonization strategy to finally prepare multileveled MoWSe2/WO3/C anode materials with core-shell petal like curled nanosheet structure. Between the petal (MoSe2)-core (WO3) structure, the formation of WSe2 flakes by partial selenization on the surface of WO3 serves as a heterogeneous con-nection between MoSe2 and WO3. The enlarged layer distance (0.677 nm) between MoSe2 and WSe2 can facilitate the rapid transfer of Na+ and electrons. The density functional theory (DFT) calculations verify that the MoWSe2/WO3/C heterostructure performs excellent metallic properties. Ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) confirm the activation process from the initial insertion reaction to the later conversion reaction. Resultantly, when employed as the anode of SIBs, a remarkable capacity of 384.3 mA h g-1 after 950 cycles at 10 A g-1 is performed. Furthermore, the SICs assembled with commercial activated carbon (AC) as the cathode exhi-bits a remarkable energy density of 81.86 W h kg-1 (at 190 W kg-1) and 72.83 W h kg-1 (at 3800 W kg-1). The unique structural design and the reaction investigation of the electrode process can provide a refer-ence for the development of transition metal chalcogenides anodes.

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Deciphering engineering principle of three-phase interface for advanced gas-involved electrochemical reactions Yanzheng He, Sisi Liu, Mengfan Wang, Qiyang Cheng, Tao Qian, Chenglin Yan 2023, 80(5): 302-323.  DOI: 10.1016/j.jechem.2023.02.002 Abstract ( 7 )   PDF (5419KB) ( 2 )   As an alternative to conventional energy conversion and storage reactions, gas-involved electrochemical reactions, including the carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR) and hydrogen evolution reaction (HER), have become an emerging research direction and have gained increasing attention due to their advantages of environmental friendliness and sustainability. Various studies have been designed to accelerate sluggish kinetics but with limited results. Most of them promote the reaction by modulating the intrinsic properties of the catalyst, ignoring the synergistic effect of the reaction as a whole. Due to the introduction of gas, traditional liquid-solid two-phase reactions are no longer applicable to future research. Since gas-involved electrochemical reactions mostly occur at the junctions of gaseous reactants, liquid electrolytes and solid catalysts, the focus of future research on reac-tion kinetics should gradually shift to three-phase reaction interfaces. In this review, we briefly introduce the formation and constraints of the three-phase interface and propose three criteria to judge its merit, namely, the active site, mass diffusion and electron mass transfer. Subsequently, a series of modulation methods and relevant works are discussed in detail from the three improvement directions of ‘exposing more active sites, promoting mass diffusion and accelerating electron transfer'. Definitively, we provide farsighted insights into the understanding and research of three-phase interfaces in the future and point out the possible development direction of future regulatory methods, hoping that this review can broaden the future applications of the three-phase interface, including but not limited to gas-involved electrochemical reactions.

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Three-in-one fire-retardant poly(phosphate)-based fast ion-conductor for all-solid-state lithium batteries Jiaying Xie, Sibo Qiao, Yuyang Wang, Jiefei Sui, Lixia Bao, He Zhou, Tianshi Li, Jiliang Wang 2023, 80(5): 324-334.  DOI: 10.1016/j.jechem.2022.12.053 Abstract ( 9 )   PDF (2163KB) ( 1 )   The development of flame retardant or nonflammable electrolytes is the key to improve the safety of lithium batteries, owing to inflammable organic solvents and polymer matrix in common liquid and poly-mer electrolytes regarded as the main cause of battery fire. Herein, a series of solid-state polyphosphate oligomers (SPPO) as a three-in-one electrolyte that integrated the roles of lithium salt, dissociation matrix, and flame retardant were synthesized. The well-designed SPPO electrolytes showed an optimal ionic conductivity of 5.5 10-4 S cm-1 at 30 °C, an acceptable electrochemical window up to 4.0 V vs. Li/Li+, and lithium ion transference number of 0.547. Stable Li-ion stripping/plating behavior for 500 h of charge-discharge cycles without internal short-circuit in a Li|SPPO|Li cell was confirmed, together with outstanding interface compatibility between the SPPO electrolyte and lithium foil. The optimal Li|SPPO| LiFePO4 cell presented good reversible discharge capacity of 149.4 mA h g-1 at 0.1 C and Coulombic effi-ciency of 96.4% after 120 cycles. More importantly, the prepared SPPO cannot be ignited by the lighter fire and show a limited-oxygen-index value as high as 35.5%, indicating splendid nonflammable nature. The SPPO could be a promising candidate as a three-in-one solid-state electrolyte for the improved safety of rechargeable lithium batteries.

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Perspective on ultrathin layered Ni-doped MoS2 hybrid nanostructures for the enhancement of electrochemical properties in supercapacitors Kamarajar Prakash, Santhanakrishnan Harish, Shanmugasundaram Kamalakannan, Thirumalaisamy Logu, Masaru Shimomura, Jayaram Archana, Mani Navaneethan 2023, 80(5): 335-349.  DOI: 10.1016/j.jechem.2023.01.002 Abstract ( 9 )   PDF (5166KB) ( 4 )   Over the last two decades, extensive study has been done on two-dimensional Molybdenum Sulphide (MoS2) due to its outstanding features in energy storage applications. Although MoS2 has a lot of active sulphur edges, the presence of inactive surfaces leads to limit conductivity and efficiency. Hence, in this article, we aimed to promote the additional active sites by doping various weight percentages (2%, 4%, 6%, 8% and 10%) of Nickel (Ni) into the MoS2 matrix by simple hydrothermal technique, and their doping effects were investigated with the help of Physio-chemical analyses. X-ray diffraction (XRD) pattern, Raman, and chemical composition (XPS) analyses were used to confirm the Ni incorporation in MoS2 nanosheets. Microscopic investigations demonstrated that Ni-doped MoS2 nanosheets were vertically aligned with enhanced interlayer spacing. Cyclic voltammetry, Galvanostatic charge-discharge, and elec-trochemical impedance spectroscopy investigations were used to characterize the electrochemical char-acteristics. The 6% Ni-doped MoS2 electrode material showed better CSP of 528.7 F/g @1 A/g and excellent electrochemical stability (85% of capacitance retention after 10,000 cycles at 5 A/g) compared to other electrode materials. Furthermore, the solid-state asymmetric supercapacitor was assembled using Ni-doped MoS2 and graphite as anode and cathode materials and analysed the electrochemical properties in the two-electrode system. To determine the impact of the Ni-atom on the MoS2 surface, first-principles computations were performed. Further, it was examined for electronic band structure, the pro-jected density of states (PDOS) and Bader charge transfer analyses.

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Synergistic double-atom catalysts of metal-boron anchored on g-C2N for electrochemical nitrogen reduction: Mechanistic insight and catalyst screening Yang Li, Wei An 2023, 80(5): 350-360.  DOI: 10.1016/j.jechem.2023.02.006 Abstract ( 9 )   PDF (3538KB) ( 2 )   The rational design of a novel catalytic center with a sound basis remains both challenging and rewarding for the electrochemical reduction of N2 (eNRR), which has provided a feasible route for achieving clean and sustainable NH3 production under ambient conditions. Herein, using density functional theory calcu-lations, we demonstrate that hybrid metal (M)-boron (B) double-atom catalysts (DACs) embedded in g-C2N substrate (M-B@C2N, M = 3d, 4d and 5d transition metals) can achieve both high catalytic activity and high selectivity in eNRR. The proposed M-B@C2N DACs have exhibited impressive feasibility and sta-bility thanks to the resilient and robust C2N substrate with abundant pyridinic N atoms distributed among right-sized pore structures. Our results reveal that like the metal center, the embedded B atom can actively involve in N„N bond activation via p*-backdonation mechanism concomitant with the sub-stantial charge transfer to adsorbed *N2, leading to sizable NAN bond elongation. Accordingly, both adsorption energy and NAN bond length of *N2 can be employed as catalytic descriptors for predicting eNRR activity in terms of the limiting potentials (UL). Using high-throughput screening method, we found that six M-B@C2N candidates have stood out as the outstanding electrocatalysts for driving eNRR, namely, M = Ti (UL = 0 V), Mo (UL = 0 V), Nb (UL = -0.04 V), W (UL = -0.23 V), Zr (UL = -0.26 V), V (UL = -0.28 V). The underlying origin is attributed to the balanced and constrained N-affinity of M-B dual site working in synergy, which can thus be used as one important guide of catalyst design.

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Variable valence Mo5+/Mo6+ ionic bridge in hollow spherical g-C3N4/ Bi2MoO6 catalysts for promoting selective visible light-driven CO2 photoreduction into CO Wenjie He, Yuechang Wei, Jing Xiong, Zhiling Tang, Yingli Wang, Xiong Wang, Hui Xu, Xiao Zhang, Xiaolin Yu, Zhen Zhao, Jian Liu 2023, 80(5): 361-372.  DOI: 10.1016/j.jechem.2023.01.028 Abstract ( 10 )   PDF (3171KB) ( 2 )   Herein, the catalysts of ultrathin g-C3N4 surface-modified hollow spherical Bi2MoO6 (g-C3N4/Bi2MoO6, abbreviated as CN/BMO) were fabricated by the co-solvothermal method. The variable valence Mo5+/ Mo6+ ionic bridge in CN/BMO catalysts can boost the rapid transfer of photogenerated electrons from Bi2MoO6 to g-C3N4. And the synergy effect of g-C3N4 and Bi2MoO6 components remarkably enhance CO2 adsorption capability. CN/BMO-2 catalyst has the best performances for visible light-driven CO2 reduction compared with single Bi2MoO6 and g-C3N4, i.e., its amount and selectivity of CO product are 139.50 lmol g-1 and 96.88% for 9 h, respectively. Based on the results of characterizations and density functional theory cal-culation, the photocatalytic mechanism for CO2 reduction is proposed. The high-efficient separation effi-ciency of photogenerated electron-hole pairs, induced by variable valence Mo5+/Mo6+ ionic bridge, can boost the rate-limiting steps (COOH*-to-CO* and CO* desorption) of selective visible light-driven CO2 con-version into CO. It inspires the establishment of efficient photocatalysts for CO2 conversion.

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Functional zirconium phosphate nanosheets enabled transfer hydrogenolysis of aromatic ether bonds over a low usage of Ru nanocatalysts Jinliang Song, Yayun Pang, Chenglei Xiao, Huizhen Liu, Buxing Han 2023, 80(5): 373-380.  DOI: 10.1016/j.jechem.2023.01.014 Abstract ( 8 )   PDF (1366KB) ( 4 )   Catalytic hydrogenolysis of aromatic ether bonds is a highly promising strategy for upgrading lignin into small-molecule chemicals, which relies on developing innovative heterogeneous catalysts with high activity. Herein, we designed porous zirconium phosphate nanosheet-supported Ru nanocatalysts (Ru/ ZrPsheet) as the heterogeneous catalyst by a process combining ball milling and molten-salt (KNO3). Very interestingly, the fabricated Ru/ZrPsheet showed good catalytic performance on the transfer hydrogenolysis of various types of aromatic ether bonds contained in lignin, i.e., 4-O-5, a-O-4, b-O-4, and aryl-O-CH3, over a low Ru usage (<0.5 mol%) without using any acidic/basic additive. Detailed inves-tigations indicated that the properties of Ru and the support were indispensable. The excellent activity of Ru/ZrPsheet originated from the strong acidity and basicity of ZrPsheet and the higher electron density of metallic Ru0 as well as the nanosheet structure of ZrPsheet.

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On-site conversion reaction enables ion-conducting surface on red phosphorus/carbon anode for durable and fast sodium-ion batteries Jiangping Song, Xin Peng, Dan Liu, Hao Li, Mengjun Wu, Kan Fang, Xinxin Zhu, Xinyuan Xiang, Haolin Tang 2023, 80(5): 381-391.  DOI: 10.1016/j.jechem.2023.01.027 Abstract ( 12 )   PDF (2902KB) ( 10 )   The practical applications of high-capacity alloy-type anode materials in sodium-ion batteries (SIBs) are challenged by their vast volume effects and resulting unstable electrode-electrolyte interphases during discharge-charge cycling. Taking red phosphorus (P)/carbon anode material as an example, we report an on-site conversion reaction to intentionally eliminate the volume effect-dominated surface P and yield an ionically conducting layer of Na3PS4 solid-state electrolyte on the composite. Such a surface recon-struction can significantly suppress the electrode swelling and simultaneously enable the activation energy of interfacial Na+ transfer as low as 36.7 kJ mol-1, resulting in excellent electrode stability and ultrafast reaction kinetics. Consequently, excellent cycling performance (510 mA h g-1 at 5 A g-1 after 1000 cycles with a tiny capacity fading rate of 0.016% per cycle) and outstanding rate capability

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Unraveling the reaction reversibility and structure stability of nickel sulfide anodes for lithium ion batteries Yu Huang, Chunyuan Liang, Yueling Cai, Yi Zhou, Bingkun Guo, Jipeng Cheng, Heguang Liu, Peng Wang, Qianqian Li, Anmin Nie, Hongtao Wang, Jinsong Wu, Tongyi Zhang 2023, 80(5): 392-401.  DOI: 10.1016/j.jechem.2023.01.010 Abstract ( 10 )   PDF (3382KB) ( 5 )   The electrochemical performance of lithium-ion batteries, i.e. specific capacity and cyclability, is primar-ily determined by chemical reversibility and structural stability of the electrodes in cycling. Here we have investigated the fundamental reaction behaviors of nickel sulfide (NixSy) as lithium-ion battery anodes by in-situ TEM. We find that Ni3S2 is the electrochemically stable phase, which appears in the first cycle of the NixSy anode. From the second cycle, conversion between Ni3S2 and Li2S/Ni is the dominant electro-chemical reaction. In lithiation, the NixSy nanoparticles evolve into a mixture of Ni nanocrystals embed-ded in Li2S matrix, which form a porous structure upon full lithiation, and with the recrystallization of the Ni3S2 phase in delithiation, a compact and interconnected network is built. Structural stability in cycles is susceptible to particle size and substrate restraint. Carbon substrate can certainly improve the tolerance for size-dependent pulverization of NixSy nanoparticles. When NixSy nanoparticle exceeds the critical size value, the morphology of the particle is no longer well maintained even under the constraints of the car-bon substrate. This work deepens the understanding of electrochemical reaction behavior of conversion-type materials and helps to rational design of high-energy density battery anodes.

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The growth of biopolymers and natural earthen sources as membrane/ separator materials for microbial fuel cells: A comprehensive review Gowthami Palanisamy, Sadhasivam Thangarasu, Ranjith Kumar Dharman, Chandrashekar S. Patil, Thakur Prithvi Pal Singh Negi, Mahaveer D. Kurkuri, Ranjith Krishna Pai, Tae Hwan Oh 2023, 80(5): 402-431.  DOI: 10.1016/j.jechem.2023.01.018 Abstract ( 41 )   PDF (10175KB) ( 21 )   Microbial fuel cell (MFC) technology has emerged as an effective solution for energy insecurity and biore-mediation. However, identifying suitable components (particularly separators or membranes) with the required properties, such as low cost and high performance, remains challenging and restricts practical application. Commercial membranes, such as Nafion, exhibit excellent performance in MFC. However, these membranes have high production costs, which considerably increase the overall MFC unit cell cost. Among the numerous types, the separators or membranes developed from biopolymers and naturally occurring earthen sources have proven to be a novel and efficient concept due to their natural abundance, cost-effectiveness (approximately $20 m-2, $5 m-2, and $1 kg-1 for biopolymers, ceramics, and earthen-sources, respectively), structural properties, proton transportation, manufacturing and modification ease, and environmental friendliness. In this review, we emphasize cost-effective renewable green materials (biopolymers, bio-derived materials, and naturally occurring soil, clay, ceramics or minerals) for MFC applications for the first time. Biopolymers with good thermal, mechanical, and water retention proper-ties, sustainability, and environmental friendliness, such as cellulose and chitosan, are typically preferred. Furthermore, the modification or introduction of various functional groups in biopolymers to enhance their functional properties and scale MFC power density is explored. Subsequently, separator/membrane development using various bio-sources (such as coconut shells, banana peels, chicken feathers, and tea waste ash) is described. Additionally, naturally occurring sources such as clay, montmorillonite, and soils (including red, black, rice-husk, and Kalporgan soil) for MFC were reviewed. In conclusion, the existing gap in MFC technology was filled by providing recommendations for future aspects based on the barriers in cost, environment, and characteristics.

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Towards storable and durable Zn-MnO2 batteries with hydrous tetraglyme electrolyte Kaixuan Ma, Gongzheng Yang, Chengxin Wang 2023, 80(5): 432-441.  DOI: 10.1016/j.jechem.2023.01.012 Abstract ( 8 )   PDF (3082KB) ( 2 )   Aqueous rechargeable zinc-based batteries have attracted increasing interest and been considered poten-tial alternatives for state-of-the-art lithium-ion batteries because of the low cost and high safety. Many cathode materials have been gradually developed and demonstrated excellent electrochemical perfor-mances. However, the complex electrochemistry, inevitable hydrogen release, and zinc corrosion severely hinder the practical application. The most concerned Zn-MnO2 batteries still suffer from the Mn dissolution and formation of byproducts. By adding organic solvents to inhibit the activity of water molecules, the hydrous organic electrolytes provide a sound solution for eliminating the unfavorable fac-tors. Here we report a tetraethylene glycol dimethyl ether-based hydrous organic electrolyte consisting of LiClO4 3H2O and Zn(ClO4)2 6H2O, and a birnessite-type MnO2 cathode material for Zn-MnO2 batteries. The Li+/Zn2+ ions co-(de)insertion mechanism is ascertained by the structural and morphological analy-ses. The electrostatic interaction between inserted ions and crystal structure is reduced effectively by employment of monovalent Li+ ions, which ensures structural stability of cathode materials. Hydrous tet-raglyme electrolyte inhibits the activity of water molecules and thus avoids the formation of byproduct Zn4ClO4(OH)7. Meanwhile, highly stable Zn plating/stripping for over 1500 h, an average coulombic effi-ciency of >99% in long-term cycling, and ultralong storage life (the cells can work well after stored over 1 year) are simultaneously realized in the novel electrolyte. Benefitting from these aspects, the Zn-MnO2 batteries manifest high specific capacity of 132 mA h g-1, an operating voltage of 1.25 V, and a capacity retention of >98% after 1000 cycles at a current density of 200 mA g-1.

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Silk fibroin-based biopolymer composite binders with gradient binding energy and strong adhesion force for high-performance micro-sized silicon anodes Panpan Dong, Xiahui Zhang, Julio Zamora, John McCloy, Min-Kyu Song 2023, 80(5): 442-451.  DOI: 10.1016/j.jechem.2023.02.010 Abstract ( 13 )   PDF (2175KB) ( 3 )   Micro-sized silicon anodes have shown much promise in large-scale industrial production of high-energy lithium batteries. However, large volume change (>300%) of silicon anodes causes severe particle pulver-ization and the formation of unstable solid electrolyte interphases during cycling, leading to rapid capac-ity decay and short cycle life of lithium-ion batteries. When addressing such issues, binder plays key roles in obtaining good structural integrity of silicon anodes. Herein, we report a biopolymer composite binder composed of rigid poly(acrylic acid) (PAA) and flexible silk fibroin (SF) tailored for micro-sized silicon anodes. The PAA/SF binder shows robust gradient binding energy via chemical interactions between car-boxyl and amide groups, which can effectively accommodate large volume change of silicon. This PAA/SF binder also shows much stronger adhesion force and improved binding towards high-surface/defective carbon additives, resulting in better electrochemical stability and higher coulombic efficiency, than con-ventional PAA binder. As such, micro-sized silicon/carbon anodes fabricated with novel PAA/SF binder exhibit much better cyclability (up to 500 cycles at 0.5 C) and enhanced rate capability compared with conventional PAA-based anodes. This work provides new insights into the design of functional binders for high-capacity electrodes suffering from large volume change for the development of next-generation lithium batteries.

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Morphological peculiarities of the lithium electrode from the perspective of the Marcus-Hush-Chidsey model Behnam Ghalami Choobar, Hamid Hamed, Mohammadhosein Safari 2023, 80(5): 452-457.  DOI: 10.1016/j.jechem.2023.01.059 Abstract ( 10 )   PDF (1275KB) ( 6 )   This study employs the kinetics framework of Marcus-Hush-Chidsey (MHC) to investigate the charge transfer at the interface of lithium electrode and electrolyte in lithium(ion)-batteries. The charge-transfer rate constant is evaluated for different facets of lithium, namely (1 0 0), (1 1 0), (1 0 1), and (1 1 1) as a function of surface charge density with the aid of density functional theory (DFT) calculations. The results highlight and quantify the sensitivity of the rate of lithium plating and stripping to the surface orientation, surface charge density, and charge-transfer over-potential. An intrinsic kinetics competition among the different surface orientations is identified together with an asymmetry between the lithium plating and stripping and showcased to influence the deposit morphology and surface protrusions and indentations.

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Integrated interface configuration by in-situ interface chemistry enabling uniform lithium deposition in all-solid-state lithium metal batteries Yu-Long Liao, Jiang-Kui Hu, Zhong-Heng Fu, Chen-Zi Zhao, Yang Lu, Shuai Li, Shi-Jie Yang, Shuo Sun, Xi-Long Wang, Jia Liu, Jia-Qi Huang, Hong Yuan 2023, 80(5): 458-465.  DOI: 10.1016/j.jechem.2023.02.012 Abstract ( 17 )   PDF (2152KB) ( 6 )   All-solid-state lithium metal batteries (ASSLMBs) are considered as one of the ultimate goals for the development of energy storage systems due to their high energy density and high safety. However, the mismatching of interface transport kinetics as well as interfacial instability induces the growth of lithium dendrite and thus, leads to severe degradation of battery electrochemical performances. Herein, an inte-grated interface configuration (IIC) consisting of in-situ generated LiI interphase and Li-Ag alloy anode is proposed through in-situ interface chemistry. The IIC is capable of not only regulating charge transport kinetics but also synchronously stabilizing the lithium/electrolyte interface, thereby achieving uniform lithium platting. Therefore, Li||Li symmetric cells with IIC achieve a critical current density of up to 1.6 mA cm-2 and achieve stable cycling over 1600 hours at a high current density of 0.5 mA cm-2. Moreover, a high discharge capacity of 140.1 mA h g-1 at 0.1 C is also obtained for the Li (Ni0.6Co0.2Mn0.2)O2 (NCM622) full battery with a capacity retention of 65.6% after 300 cycles. This work provides an effective method to synergistically regulate the interface transport kinetics and inhibit lithium dendrite growth for high-performance ASSLMBs.

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Green and sustainably designed intercalation-type anodes for emerging lithium dual-ion batteries with high energy density Tejaswi Tanaji Salunkhe, Abhijit Nanaso Kadam, Jaehyun Hur, Il Tae Kim 2023, 80(5): 466-478.  DOI: 10.1016/j.jechem.2023.01.051 Abstract ( 8 )   PDF (5134KB) ( 2 )   Lithium dual-ion batteries (LiDIBs) have attracted significant attention owing to the growing demand for modern anode materials with high energy density. Herein, rust encapsulated in graphite was achieved by utilizing ammonium bicarbonate (ABC) as a template, which resulted in mesoporous Fe3O4 embedded in expanded carbon (Fe3O4@G (ABC)) via simple ball milling followed by annealing. This self-assembly approach for graphite-encapsulated Fe3O4 composites helps enhance the electrochemical performance, such as the cycling stability and superior rate stability (at 3 A/g), with improved conductivity in LiDIBs. Specifically, Fe3O4@G-1:4(ABC) and Fe3O4@G-1:6(ABC) anodes in a half-cell at 0.1 A/g delivered initial capacities of 1390.6 and 824.4 mA h g-1, respectively. The optimized anode (Fe3O4@G-1:4(ABC)) coupled with the expanded graphite (EG) cathode in LiDIBs provided a substantial initial specific capacity of 260.9 mA h g-1 at 1 A/g and a specific capacity regain of 106.3 mA h g-1 (at 0.1 A/g) after 250 cycles, with a very high energy density of 387.9 Wh kg-1. The strategically designed Fe3O4@G accelerated Li-ion kinetics, alleviated the volume change, and provided an efficient conductive network with excellent mechanical flexibility, resulting in exceptional performance in LiDIBs. Various postmortem analyses of the anode and cathode (XRD, Raman, EDS, and XPS) are presented to explain the intercalation-type elec-trochemical mechanisms of LiDIBs. This study offers several advantages, including safety, low cost, sus-tainability, environmental friendliness, and high energy density.

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Finned Zn-MFI zeolite encapsulated noble metal nanoparticle catalysts for the oxidative dehydrogenation of propane with carbon dioxide En-Hui Yuan, Yiming Niu, Xing Huang, Meng Li, Jun Bao, Yong-Hong Song, Bingsen Zhang, Zhao-Tie Liu, Marc-Georg Willinger, Zhong-Wen Liu 2023, 80(5): 479-491.  DOI: 10.1016/j.jechem.2023.01.055 Abstract ( 4 )   PDF (2971KB) ( 3 )   Oxidative dehydrogenation of propane with carbon dioxide (CO2-ODP) characterizes the tandem dehy-drogenation of propane to propylene with the reduction of the greenhouse gas of CO2 to valuable CO. However, the existing catalyst is limited due to the poor activity and stability, which hinders its indus-trialization. Herein, we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles (NPs) as bifunctional catalysts (NPs@Zn-MFI) for CO2-ODP. Characterization results reveal that the Zn2+ species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt, Rh, or RhPt are highly dispersed in the zeolite crystals. The isolated Zn2+ cations are very effective for activating the propane and the small NPs are favorable for activating the CO2, which synergistically promote the selective transfor-mation of propane and CO2 to propylene and CO. As a result, the optimal 0.25%Rh0.50%Pt@Zn-MFI cata-lyst shows the best propylene yield, satisfactory CO2 conversion, and long-term stability. Moreover, considering the tunable synergetic effects between the isolated cations and NPs, the developed approach offers a general guideline to design more efficient CO2-ODP catalysts, which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+ cations for Zn2+ cations in the MFI zeolite matrix.

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Green recycling of short-circuited garnet-type electrolyte for high-performance solid-state lithium batteries Yongxian Huang, Zhiwei Qin, Cheng Shan, Yuming Xie, Xiangchen Meng, Delai Qian, Gang He, Dongxin Mao, Long Wan 2023, 80(5): 492-500.  DOI: 10.1016/j.jechem.2023.01.057 Abstract ( 9 )   PDF (3341KB) ( 4 )   Solid-state lithium batteries (SSLBs) solve safety issues and are potentially energy-dense alternatives to next-generation energy storage systems. Battery green recycling routes are responsible for the wide-spread use of SSLBs due to minimizing environmental contamination, reducing production costs, and providing a sustainable solution for resources, e.g., saving rare earth elements (La, Ta, etc.). Herein, a solid-state recycling strategy is proposed to achieve green recycling of the crucial component solid-state electrolytes (SSEs) in spent SSLBs. The short-circuited garnet Li6.5La3Zr1.5Ta0.5O12 (LLZTO) is broken into fine particles and mixed with fresh particles to improve sintering activity and achieve high packing density. The continuous Li absorption process promotes sufficient grain fusion and guarantees the trans-formation from tetragonal phase to pure cubic phase for high-performance recycled LLZTO. The Li-ion conductivity reaches 5.80 10-4 S cm-1 with a relative density of 95.9%. Symmetric Li cell with as-recycled LLZTO shows long-term cycling stability for 700 h at 0.3 mA cm-2 without any voltage hystere-sis. Full cell exhibits an excellent cycling performance with a discharge capacity of 141.5 mA h g-1 and a capacity retention of 92.1% after 400 cycles (0.2C). This work develops an environmentally friendly and economically controllable strategy to recycle SSE from spent SSLBs, guiding future directions of SSLBs large-scale industrial application and green recycling study.

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Metal-organic frameworks based single-atom catalysts for advanced fuel cells and rechargeable batteries Yifei Wu, Peng Hu, Fengping Xiao, Xiaoting Yu, Wenqi Yang, Minqi Liang, Ziwei Liang, Aixin Zhu 2023, 80(5): 501-534.  DOI: 10.1016/j.jechem.2023.01.054 Abstract ( 4 )   PDF (10232KB) ( 1 )   The next-generation energy storage systems such as fuel cells, metal-air batteries, and alkali metal (Li, Na)-chalcogen (S, Se) batteries have received increasing attention owing to their high energy density and low cost. However, one of the main obstacles of these systems is the poor reaction kinetics in the involved chemical reactions. Therefore, it is essential to incorporate suitable and efficient catalysts into the cell. These years, single-atom catalysts (SACs) are emerging as a frontier in catalysis due to their max-imum atom efficiency and unique reaction selectivity. For SACs fabrication, metal-organic frameworks (MOFs) have been confirmed as promising templates or precursors due to their high metal loadings, structural adjustability, porosity, and tailorable catalytic site. In this review, we summarize effective strategies for fabricating SACs by MOFs with corresponding advanced characterization techniques and illustrate the key role of MOFs-based SACs in these batteries by explaining their reaction mechanisms and challenges. Finally, current applications, prospects, and opportunities for MOFs-based SACs in energy storage systems are discussed.

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Coupling interface engineering with electronic interaction toward high-efficiency H2 evolution in pH-universal electrolytes Jinli Chen, Tianqi Yu, Zhixiang Zhai, Guangfu Qian, Shibin Yin 2023, 80(5): 535-541.  DOI: 10.1016/j.jechem.2023.01.060 Abstract ( 19 )   PDF (1850KB) ( 11 )   Herein, the merits of heterojunction, CeO2, and W are employed to design and prepare the PtCoW@CeO2 heterojunction catalyst, which can accelerate water dissociation and improve the desorption of OHad, dis-playing efficient hydrogen evolution reaction (HER) performance in pH-universal conditions. Density functional theory calculation results reveal that the electronic structure of Pt is regulated by CeO2 and W, which tunes the Pt-Had bond strength to boost HER intrinsic activity. Consequently, electrochemical results display that it has low potentials of -26, -25, and -23 mV at -10 mA cm-2 in alkaline, neutral, and acidic solutions, respectively, and it can stably cycle for 50,000 cycles. Thus, this work provides the guidance for developing high-performance Pt-based catalysts in pH-universal environments.

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Regulating single-atom Mn sites by precisely axial pyridinic-nitrogen coordination to stabilize the oxygen reduction Yuan Qin, Chaozhong Guo, Zihao Ou, Chuanlan Xu, Qi Lan, Rong Jin, Yao Liu, Yingchun Niu, Quan Xu, Yujun Si, Honglin Li 2023, 80(5): 542-552.  DOI: 10.1016/j.jechem.2023.01.048 Abstract ( 17 )   PDF (2994KB) ( 11 )   Designing single-atom catalysts for oxygen reduction reaction (ORR) are fashionable but challenging to boost the zinc-air battery performance. Significantly enhanced ORR activity by manganese (Mn) single-atom catalysts can be achieved by accurately regulating the coordination number of isolated Mn atoms. Theoretical calculations indicate that the single Mn-N5 sites possess lower free energy barrier and higher oxygen adsorption performance than single Mn-N4 sites to accelerate the ORR kinetics. Target to it, here we synthesize an atomically dispersed Mn-N5 catalyst by precisely axial coordination of pyridinic-N doped into two-dimensional (2D) porous nanocarbon sheets (~3.56 nm thickness), which reveals out-standing catalytic activity and ultrahigh stability for the ORR in zinc-air battery owing to the inhomoge-neous charge distribution of Mn-N sites compared to the conventional single-site Mn-N catalyst and Pt/Oxygen reduction reaction, Coordination number Axial pyridinic-nitrogen coordination C. This work gives a new strategy for in situ regulating the electronic structure of metal single-atoms and further promoting the overall ORR performance in energy systems.

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Spontaneous local redox reaction to passivate CNTs as lightweight current collector for high energy density lithium ion batteries Chao Lv, Zhen Tong, Shi-Yuan Zhou, Si-Yu Pan, Hong-Gang Liao, Yao Zhou, Jun-Tao Li 2023, 80(5): 553-561.  DOI: 10.1016/j.jechem.2023.01.056 Abstract ( 8 )   PDF (2144KB) ( 3 )   Extensive usage of highly conductive carbon materials with large specific surface area (e.g., carbon nan-otubes, CNTs) in lithium ion batteries (LIBs), especially as current collector of anodes, suffers from low initial coulombic efficiency (ICE), large interfacial resistance, and severe embrittlement, as the large specific surface area often results in severe interfacial decomposition of the electrolyte and the formation of thick and fluffy solid electrolyte interphase (SEI) during cycling of LIBs. Herein, we demonstrate that when the CNT-based current collector and Na foil (which are being stacked intimately upon each other) are being placed in Na+-based organic electrolyte, local redox reaction between the Na foil and the elec-trolyte would occur spontaneously, generating a thin and homogeneous NaF-based passivating layer on the CNTs. More importantly, we found that owing to the weak solvation behaviors of Na+ in the organic electrolyte, the resulting passivation layer, which is rich in NaF, is thin and dense; when used as the anode current collector in LIBs, the pre-existing passivating layer can function effectively in isolating the anode from the solvated Li+, thus suppressing the formation of bulky SEI and the destructive interca-lation of solvated Li+. The relevant half-cell (graphite as anode) exhibits a high ICE of 92.1%; the relevant pouch cell with thus passivated CNT film as current collectors for both electrodes (LiCoO2 as cathode, gra-phite as anode) displays a high energy density of 255 Wh kg-1, spelling an increase of 50% compared with that using the conventional metal current collectors.

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Metal derivative (MD)/g-C3N4 association in hydrogen production:A study on the fascinating chemistry behind, current trend and future direction Athira Krishnan, Muhsina Yoosuf, K. Archana, A.S. Arsha, Amritha Viswam 2023, 80(5): 562-583.  DOI: 10.1016/j.jechem.2023.02.008 Abstract ( 8 )   PDF (2503KB) ( 3 )   Metal derivative/graphitic carbon nitride (g-C3N4) association is found promising in providing sustain-able hydrogen production by photocatalytic water splitting process. Number of works reported on the synthesis and application of various metal based g-C3N4 composites are increasing day by day. Mechanism of charge separation varies according to the metal candidate that gets couple with g-C3N4. The present article thus explores the interesting chemistry behind various metal based heterojunction and demonstrates the charge separation route. A thorough investigation has been done on the current research trend in the area. As many metal free g-C3N4 composites are reported nowadays as an alterna-tive to metal derivatives, here compares metallic and metal free derivatives of g-C3N4 based on four crit-ical requirements of an industrial catalyst, ie, activity, stability, cost and toxicity. Challenges and future direction in the area are also discussed with significance. The systematic discussion and schematic illus-tration of charge transfer process in different heterojunctions with reference to the reported systems, given in the article can definitely contribute to the design and development of more efficient g-C3N4 based heterojunctions in future for hydrogen production application.

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Enhancing long-term stability of bio-photoelectrochemical cell by defect engineering of a WO3-x photoanode Cheng Zhang, Xuchao Zheng, Yongyue Ning, Zihan Li, Zhongdong Wu, Xiaoyu Feng, Gangyong Li, Zhongyuan Huang, Zongqian Hu 2023, 80(5): 584-593.  DOI: 10.1016/j.jechem.2023.02.003 Abstract ( 14 )   PDF (1998KB) ( 7 )   Bio-photoelectrochemical cells (BPECs) can further expand the use of conventional biofuel cells for renewable energy, but the poor stability of the photoelectrode still hinders their practical application. Herein, a BPEC capable of long-term operating in a fuel-free model is fabricated by WO3-x photoanode with oxygen vacancy (Ov) and bilirubin oxidase catalyzed biocathode. The construction of Ov on the WO3 surface significantly suppresses the dissolution of W species into the electrolyte, and improves the charge separation efficiency and the reaction kinetics during the photoelectrochemical oxygen evo-lution process, thus enhancing the stability and power output performance of the BPEC. As a result, the assembled BPEC can output an open circuit voltage of 0.81 V and deliver a maximum output power of up to 283 lW cm-2. Impressively, the BPECs maintain 97% of their original power after 36000 s of con-secutive discharge under an enclosed environment. This fuel-free BPEC based on a robust WO3-x photoan-ode shows excellent promise for accurate application.

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Metal-oxoacid-mediated oxyhydroxide with proton acceptor to break adsorption energy scaling relation for efficient oxygen evolution Rongrong Zhang, Beibei Guo, Lun Pan, Zhen-Feng Huang, Chengxiang Shi, Xiangwen Zhang, Ji-Jun Zou 2023, 80(5): 594-602.  DOI: 10.1016/j.jechem.2023.02.024 Abstract ( 6 )   PDF (1974KB) ( 2 )   Metal oxyhydroxides (MOOH) generated from irreversible reconstructions of transition metal com-pounds are intrinsic active species for oxygen evolution reaction, whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling relations. Herein, we construct a tunable proton acceptor (TPA) on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4 to accelerate deprotonation and break adsorption energy scaling relations during OER. The mod-ified C O2- as a TPA can easily extract H of *OH (forming *HC O intermediate) and then promote depro-tonation by the transmitted hydrogen bond with *OOH along conjugated (H···)O@C-O(-H) chain. As a result, NiOOH-C2O4 shows non-concerted proton-electron transfer and improved deprotonation rate, and delivers a good OER activity (270 mV@10 mA cm-2). The conjugate acidity coefficient (pKa) of the modified oxoacid group can be a descriptor for TPA selection. This TPA strategy can be universally applied to Co-, Fe-, and Ni-based oxyhydroxides to facilitate OER efficiency.

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Regulating the electrochemical activity of Fe-Mn-Cu-based layer oxides as cathode materials for high-performance Na-ion battery Ting-Ting Wei, Xu Liu, Shao-Jie Yang, Peng-Fei Wang, Ting-Feng Yi 2023, 80(5): 603-613.  DOI: 10.1016/j.jechem.2023.02.016 Abstract ( 23 )   PDF (3586KB) ( 20 )   Fe-Mn based layer oxides cathode materials have attracted widespread attention as a potential candidate for sodium-ion batteries (SIBs) owing to the earth abundance, cost-effectiveness and acceptable specific capacity. However, the irreversible phase transition often brings rapid capacity decay, which seriously hinders the practical application in large-scale energy storage. Herein, we design a nickel-doped Na0.70Fe0.10Cu0.20Ni0.05Mn0.65O2 (NFCNM-0.05) cathode material of SIBs with activated anionic redox reaction, and then inhibit the harmful phase transition. The ex-situ X-ray diffraction patterns demon-strate the NFCNM-0.05 always keeps the P2 phase during the sodiation/desodiation process, indicating a high structure stability. The ex-situ X-ray photoelectron spectroscopy implies the redox reactions between O2- and O- occur in the charging process, which offers extra specific capacity. Thus, the NFCNM-0.05 electrode delivers a high initial discharge capacity of 148 mA h g-1 and remains a prominent cycling stability with an excellent capacity retention of 95.9% after 200 cycles at 1 C. In addition, the elec-trochemical impedance spectroscopy and galvanostatic intermittent titration technique show the NFCNM-0.05 electrode possesses fast ion diffusion ability, which is beneficial for the enhancement of rate performance. Even at 10 C, the NFCNM-0.05 can offer a reversible discharge capacity of 81 mA h g-1. DFT calculation demonstrates the doping of appropriate amount of Ni ions is benefit for the enhancement of the electrochemical performance of the layer oxides. This work provides an effective strategy to enhance the electrochemical performance of Fe-Mn based cathode materials of SIBs.

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Boosting CO2 hydrogenation to high-value olefins with highly stable performance over Ba and Na co-modified Fe catalyst Joshua Iseoluwa Orege, Na Liu, Cederick Cyril Amoo, Jian Wei, Qingjie Ge, Jian Sun 2023, 80(5): 614-624.  DOI: 10.1016/j.jechem.2023.02.007 Abstract ( 13 )   PDF (1884KB) ( 4 )   CO2 hydrogenation has been considered to be a highly promising route for the production of high-value olefins (HVOs) while also mitigating CO2 emissions. However, it is challenging to achieve high selectivity and maintain stable performance for HVOs (ethylene, propylene, and linear a-olefins) over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst deactivation. Herein, we present a selective Ba and Na co-modified Fe catalyst enriched with Fe5C2 and Fe3C active sites that can boost HVO synthesis with up to 66.1% selectivity at an average CO2 conversion of 38% for over 500 h. Compared to traditional NaFe catalyst, the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCx sites by H2O. The absence of Fe3O4 phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the FeCx sites. This study pro-vides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO2 hydrogenation.

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Toward high-sulfur-content, high-performance lithium-sulfur batteries: Review of materials and technologies Fulai Zhao, Jinhong Xue, Wei Shao, Hui Yu, Wei Huang, Jian Xiao 2023, 80(5): 625-657.  DOI: 10.1016/j.jechem.2023.02.009 Abstract ( 10 )   PDF (7903KB) ( 4 )   Lithium sulfur batteries (LSBs) are recognized as promising devices for developing next-generation energy storage systems. In addition, they are attractive rechargeable battery systems for replacing lithium-ion batteries (LIBs) for commercial use owing to their higher theoretical energy density and lower cost compared to those of LIBs. However, LSBs are still beset with some persistent issues that pre-vent them from being used industrially, such as the unavoidable dissolution of lithium polysulfide inter-mediates during electrochemical reactions and large volume expansion (up to 80%) upon the formation of Li2S, resulting in serious battery life and safety limitations. In the process of solving these problems, it is necessary to maintain a high sulfur content in the cathode materials to ensure that the LSBs have high energy densities and excellent cycle performance. In this review, the novel preparation methods and cathode materials used for preparing LSBs in recent years are reviewed considering the sulfur content and cycle performance. In addition, the problems and difficulties in practically applying cathode materi-als are described, and the development trend is discussed.

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Emerging trends of electrocatalytic technologies for renewable hydrogen energy from seawater: Recent advances, challenges, and techno-feasible assessment Obaid Fahad Aldosari, Ijaz Hussain, Zuhair Malaibari 2023, 80(5): 658-688.  DOI: 10.1016/j.jechem.2023.01.067 Abstract ( 16 )   PDF (4699KB) ( 6 )   Hydrogen has been regarded as a promising renewable and green energy source to meet energy needs and attain net-zero carbon emissions. The electrolysis of seawater to make hydrogen is one of the fascinating developments of the twenty-first century. This method uses abundant and relatively inexpensive seawater, as opposed to freshwater, which is rare and can be prohibitively expensive. In recent years, significant research and advancements have been made in direct seawater electrolysis technology for hydrogen pro-duction. However, producing highly effective and efficient electrocatalysts with long-term viability under harsh corrosive conditions remains a challenging and severe topic for large-scale seawater electrolysis technology. There is still a large accomplishment gap in understanding how to improve seawater electrol-ysis to increase hydrogen yields and prolong stability. It is, therefore, crucial to have a condensed knowl-edge of the tunable and inherent interactions between various electrocatalysts, covering electrolyzer types and paying particular attention to those with high efficiency, chemical stability, and conductivity. The extensive discussion is structured into a progression from noble metals to base metal compounds such as oxides, alloys, phosphides, chalcogenides, hydroxides, and nitrides, MXene-based complexes with a con-cise examination of hybrid electrocatalysts. In addition, proton exchange membranes, anion exchange membranes, alkaline water electrolyzers, and high-temperature water electrolyzers were potential con-tributors to seawater's electrolysis. An extensive assessment of the techno-feasibility, economic insights, and future suggestions was done to commercialize the most efficient electrocatalytic systems for hydrogen production. This review is anticipated to provide academics, environmentalists, and industrial researchers with valuable ideas for constructing and modifying seawater-based electrocatalysts.

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Solvent engineering towards scalable fabrication of high-quality perovskite films for efficient solar modules Zhaoyi Jiang, Binkai Wang, Wenjun Zhang, Zhichun Yang, Mengjie Li, Fumeng Ren, Tahir Imran, Zhenxing Sun, Shasha Zhang, Yiqiang Zhang, Zhiguo Zhao, Zonghao Liu, Wei Chen 2023, 80(5): 689-710.  DOI: 10.1016/j.jechem.2023.02.017 Abstract ( 66 )   PDF (5672KB) ( 35 )   Over the last decade, remarkable progress has been made in metal halide perovskite solar cells (PSCs), which have been a focus of emerging photovoltaic techniques and show great potential for commercial-ization. However, the upscaling of small-area PSCs to large-area solar modules to meet the demands of practical applications remains a significant challenge. The scalable production of high-quality perovskite films by a simple, reproducible process is crucial for resolving this issue. Furthermore, the crystallization behavior in the solution-processed fabrication of perovskite films can be strongly influenced by the physicochemical properties of the precursor inks, which are significantly affected by the employed sol-vents and their interactions with the solutes. Thus, a comprehensive understanding of solvent engineer-ing for fabricating perovskite films over large areas is urgently required. In this paper, we first analyze the role of solvents in the solution-processed fabrication of large-area perovskite films based on the classical crystal nucleation and growth mechanism. Recent efforts in solvent engineering to improve the quality of perovskite films for solar modules are discussed. Finally, the basic principles and future challenges of sol-vent system design for scalable fabrication of high-quality perovskite films for efficient solar modules are proposed.

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Low molecular weight alkane-fed solid oxide fuel cells for power and chemicals cogeneration Ermete Antolini 2023, 80(5): 711-735.  DOI: 10.1016/j.jechem.2023.01.033 Abstract ( 7 )   PDF (2736KB) ( 2 )   This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells (SOFCs), which, unlikely the conventional use of SOFCs for only power production, are utilized to cogenerate produce use-ful chemicals at the same time. The cogeneration processes in SOFC have been classified according to the different types of fuel. C2 and C3 alkenes and synthesis gas are the main cogenerated chemicals together with electricity. The chemicals and energy cogeneration in a fuel cell reactor seems to be an effective alternative to conventional reactors for only chemicals production and conventional fuel cells for only power production. Although, the use of SOFCs for chemicals and energy cogeneration has proved success-ful in the industrial setting, the development of new catalysts aimed at obtaining the desired chemicals together with the production of a high amount of energy, and optimizing SOFC operation conditions is still a challenge to enhance system performance and make commercial applications workable.

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Novel ternary metals-based telluride electrocatalyst with synergistic effects of high valence non-3d metal and oxophilic Te for pH-universal hydrogen evolution reaction Seunghwan Jo, Wenxiang Liu, Yanan Yue, Ki Hoon Shin, Keon Beom Lee, Hyeonggeun Choi, Bo Hou, Jung Inn Sohn 2023, 80(5): 736-743.  DOI: 10.1016/j.jechem.2023.02.011 Abstract ( 7 )   PDF (1514KB) ( 2 )   Electrocatalyst designs based on oxophilic foreign atoms are considered a promising approach for devel-oping efficient pH-universal hydrogen evolution reaction (HER) electrocatalysts by overcoming the slug-gish alkaline HER kinetics. Here, we design ternary transition metals-based nickel telluride (MoWNiTe) catalysts consisting of high valence non-3d Mo and W metals and oxophilic Te as a first demonstration of non-precious heterogeneous electrocatalysts following the bifunctional mechanism. The MoWNiTe showed excellent HER catalytic performance with overpotentials of 72, 125, and 182 mV to reach the cur-rent densities of 10, 100, and 1000 mA cm-2, respectively, and the corresponding Tafel slope of 47, 52, and 58 mV dec-1 in alkaline media, which is much superior to commercial Pt/C. Additionally, the HER performance of MoWNiTe is well maintained up to 3000 h at the current density of 100 mA cm-2. It is further demonstrated that the MoWNiTe exhibits remarkable HER activities with an overpotential of 45 mV (31 mV) and Tafel slope of 60 mV dec-1 (34 mV dec-1) at 10 mA cm-2 in neutral (acid) media. The superior HER performance of MoWNiTe is attributed to the electronic structure modulation, inducing highly active low valence states by the incorporation of high valence non-3d transition metals. It is also attributed to the oxophilic effect of Te, accelerating water dissociation kinetics through a bifunctional cat-alytic mechanism in alkaline media. Density functional theory calculations further reveal that such syn-ergistic effects lead to reduced free energy for an efficient water dissociation process, resulting in remarkable HER catalytic performances within universal pH environments.

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Transfer learning aided high-throughput computational design of oxygen evolution reaction catalysts in acid conditions Siwen Wang, Honghong Lin, Yui Wakabayashi, Li Qin Zhou, Charles A. Roberts, Debasish Banerjee, Hongfei Jia, Chen Ling 2023, 80(5): 744-757.  DOI: 10.1016/j.jechem.2023.02.004 Abstract ( 5 )   PDF (2566KB) ( 2 )   Sluggish oxygen evolution reaction (OER) in acid conditions is one of the bottlenecks that prevent the wide adoption of proton exchange membrane water electrolyzer for green hydrogen production. Despite recent advancements in developing high-performance catalysts for acid OER, the current electro-catalysts still rely on iridium-and ruthenium-based materials, urging continuous efforts to discover bet-ter performance catalysts as well as reduce the usage of noble metals. Pyrochlore structured oxide is a family of potential high-performance acid OER catalysts with a flexible compositional space to tune the electrochemical capabilities. However, exploring the large composition space of pyrochlore compounds demands an imperative approach to enable efficient screening. Here we present a high-throughput screening pipeline that integrates density functional theory calculations and a transfer learn-ing approach to predict the critical properties of pyrochlore compounds. The high-throughput screening recommends three sets of candidates for potential acid OER applications, totaling 61 candidates from 6912 pyrochlore compounds. In addition to 3d-transition metals, p-block metals are identified as promis-ing dopants to improve the catalytic activity of pyrochlore oxides. This work demonstrates not only an efficient approach for finding suitable pyrochlores towards acid OER but also suggests the great compo-sitional flexibility of pyrochlore compounds to be considered as a new materials platform for a variety of applications.

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Cryoactivated proton-involved redox reactions enable stable-cycling fiber cooper metal batteries operating at —50 °C Changyuan Yan, Zixuan Chen, Hongzhong Deng, Hao Huang, Xianyu Deng 2023, 80(5): 758-767.  DOI: 10.1016/j.jechem.2023.02.026 Abstract ( 7 )   PDF (4027KB) ( 2 )   Fiber-shaped batteries that feature outstanding flexibility, light weight, and wovenability are extremely attractive for powering smart wearable electronic textiles, which further stimulates their demand in extreme environments. However, there are rare reports on ultralow-temperature fiber batteries to date. This is mainly attributed to the poor conductivity of electrodes and freezing of electrolytes that restrain their satisfactory flexible operation in cold environments. Herein, we propose a fiber cooper metal battery consisting of a conductive polyaniline cathode, an anti-freezing Cu(BF4)2 + H3PO4 electrolyte and an acid-resistant copper wire anode, which can withstand various deformations at ultralow temperatures. Impressively, enhanced capacity and cyclic stability can be achieved by cryoactivated abundant reactive sites in the polyaniline, while benefiting from redox reactions with rapid kinetics involving protons rather than copper ions. Consequently, this well-designed polyaniline/Cu fiber battery delivers excellent flexibility without obvious capacity decay after being bent at -30 °C, as well as a remarkable discharge capacity of 120.1 mA h g-1 and a capacity retention of 96.8% after 2000 cycles at -50 °C. The fiber bat-teries integrated into wearable textiles can power various electronic devices. These performances greatly outperform those of most reported works. Overall, this work provides a promising strategy toward appli-cations of cryogenic wearable energy storage devices.

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Robust state of charge estimation of lithium-ion battery via mixture kernel mean p-power error loss LSTM with heap-based-optimizer Wentao Ma, Yiming Lei, Xiaofei Wang, Badong Chen 2023, 80(5): 768-784.  DOI: 10.1016/j.jechem.2023.02.019 Abstract ( 8 )   PDF (7174KB) ( 3 )   The state of charge (SOC) estimation of lithium-ion battery is an important function in the battery manage-ment system (BMS) of electric vehicles. The long short term memory (LSTM) model can be employed for SOC estimation, which is capable of estimating the future changing states of a nonlinear system. Since the BMS usually works under complicated operating conditions, i.e the real measurement data used for model train-ing may be corrupted by non-Gaussian noise, and thus the performance of the original LSTM with the mean square error (MSE) loss may deteriorate. Therefore, a novel LSTM with mixture kernel mean p-power error (MKMPE) loss, called MKMPE-LSTM, is developed by using the MKMPE loss to replace the MSE as the learn-ing criterion in LSTM framework, which can achieve robust SOC estimation under the measurement data contaminated with non-Gaussian noises (or outliers) because of the MKMPE containing the p-order moments of the error distribution. In addition, a meta-heuristic algorithm, called heap-based-optimizer (HBO), is employed to optimize the hyper-parameters (mainly including learning rate, number of hidden layer neuron and value of p in MKMPE) of the proposed MKMPE-LSTM model to further improve its flexi-bility and generalization performance, and a novel hybrid model (HBO-MKMPE-LSTM) is established for SOC estimation under non-Gaussian noise cases. Finally, several tests are performed under various cases through a benchmark to evaluate the performance of the proposed HBO-MKMPE-LSTM model, and the results demonstrate that the proposed hybrid method can provide a good robustness and accuracy under different non-Gaussian measurement noises, and the SOC estimation results in terms of mean square error (MSE), root MSE(RMSE), mean absolute relative error (MARE), and determination coefficient R2 are less than 0.05%, 3%, 3%,and above 99.8% at 25℃, respectively.