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2023, Vol. 78, No. 3　Online: 15 March 2023

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Physics-informed neural network approach for heat generation rate estimation of lithium-ion battery under various driving conditions Hui Pang, Longxing Wu, Jiahao Liu, Xiaofei Liu, Kai Liu 2023, 78(3): 1-12.  DOI: 10.1016/j.jechem.2022.11.036 Abstract ( 50 )   PDF (1707KB) ( 41 )   Accurate insight into the heat generation rate (HGR) of lithium-ion batteries (LIBs) is one of key issues for battery management systems to formulate thermal safety warning strategies in advance. For this reason, this paper proposes a novel physics-informed neural network (PINN) approach for HGR estimation of LIBs under various driving conditions. Specifically, a single particle model with thermodynamics (SPMT) is first constructed for extracting the critical physical knowledge related with battery HGR. Subsequently, the surface concentrations of positive and negative electrodes in battery SPMT model are integrated into the bidirectional long short-term memory (BiLSTM) networks as physical information. And combined with other feature variables, a novel PINN approach to achieve HGR estimation of LIBs with higher accuracy is constituted. Additionally, some critical hyperparameters of BiLSTM used in PINN approach are determined through Bayesian optimization algorithm (BOA) and the results of BOA-based BiLSTM are compared with other traditional BiLSTM/LSTM networks. Eventually, combined with the HGR data generated from the validated virtual battery, it is proved that the proposed approach can well predict the battery HGR under the dynamic stress test (DST) and worldwide light vehicles test procedure (WLTP), the mean absolute error under DST is 0.542 kW/m3, and the root mean square error under WLTP is 1.428 kW/m3 at 25 C. Lastly, the investigation results of this paper also show a new perspective in the application of the PINN approach in battery HGR estimation.

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Towards extreme fast charging of 4.6 V LiCoO2 via mitigating high-voltage kinetic hindrance Yu Tang, Jun Zhao, He Zhu, Jincan Ren, Wei Wang, Yongjin Fang, Zhiyong Huang, Zijia Yin, Yalan Huang, Binghao Zhang, Tingting Yang, Tianyi Li, Leighanne C. Gallington, Si Lan, Yang Ren, Qi Liu 2023, 78(3): 13-20.  DOI: 10.1016/j.jechem.2022.11.044 Abstract ( 22 )   PDF (1455KB) ( 14 )   High-voltage LiCoO2 (LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries (LIBs) in the 3 C markets. However, the sluggish lithium-ion diffusion at high voltage significantly ham-pers its rate capability. Herein, combining experiments with density functional theory (DFT) calculations, we demonstrate that the kinetic limitations can be mitigated by a facial Mg2++Gd3+ co-doping method. The as-prepared LCO shows significantly enhanced Li-ion diffusion mobility at high voltage, making more homogenous Li-ion de/intercalation at a high-rate charge/discharge process. The homogeneity enables the structural stability of LCO at a high-rate current density, inhibiting stress accumulation and irre-versible phase transition. When used in combination with a Li metal anode, the doped LCO shows an extreme fast charging (XFC) capability, with a superior high capacity of 193.1 mAh g-1 even at the current density of 20 C and high-rate capacity retention of 91.3% after 100 cycles at 5 C. This work provides a new insight to prepare XFC high-voltage LCO cathode materials.

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Super-exchange effect induced by early 3d metal doping on NiFe2O4(001) surface for oxygen evolution reaction Shuhao Wang, Xinyan Liu, Xiang Chen, Kamran Dastafkan, Zhong-Heng Fu, Xin Tan, Qiang Zhang, Chuan Zhao 2023, 78(3): 21-29.  DOI: 10.1016/j.jechem.2022.11.025 Abstract ( 20 )   PDF (1901KB) ( 17 )   Understanding the intrinsic activity of oxygen evolution reaction (OER) is crucial for catalyst design. To date, different metal-doping strategies have been developed to achieve this, but the involving mecha-nisms remain unclear. Here, the electronic structure of the transition metal-doped NiFe2O4(001) surface is scrutinized for OER intrinsic activity using density functional theory calculations. Five 3d-orbital filling metals (Ti, V, Cr, Mn, and Co) are introduced as dopants onto A- and B-layers of the NiFe2O4(001) surface, and variation of oxidation states over Fe sites is observed on B-layer. Analyzing the magnetic moment and charge transfer of surface cation sites reveals that the variation of Fe oxidation states originates from the super-exchange effect and is infiuenced by the t2g-electron configuration of 3d metal dopants. This trend governs the generation of highly-active Fe3+ sites on the B-layer, the adsorption strength of OER interme-diates, i.e., *O and *OH, and therefore the intrinsic activity. The finding of super-exchange mechanism induced by 3d early metal doping offers insights into electronic structure tailoring strategies for improv-ing the intrinsic activity of OER electrocatalysts.

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Carbon nanotube-hyperbranched polymer core-shell nanowires with highly accessible redox-active sites for fast-charge organic lithium batteries Zhonghui Sun, Meng Shu, Jiabin Li, Bing Liu, Hongyan Yao, Shaowei Guan, Zhenhua Sun 2023, 78(3): 30-36.  DOI: 10.1016/j.jechem.2022.11.014 Abstract ( 15 )   PDF (1819KB) ( 6 )   Organic electrode materials are promising for lithium-ion batteries (LIBs) because of their environmental friendliness and structural diversity. However, they always suffer from limited capacity, poor cycling sta-bility, and rate performance. Herein, hexaazatrinaphthalene-based azo-linked hyperbranched polymer (HAHP) is designed and synthesized as a cathode for LIBs. However, the densely stacked morphology low-ers the chance of the active sites participating in the redox reaction. To address this issue, the single-walled carbon nanotube (SWCNT) template is used to induce the growth of nanosized HAHP on the sur-face of SWCNTs. The HAHP@SWCNT nanocomposites have porous structures and highly accessible active sites. Moreover, the strong p-p interaction between HAHP and highly conductive SWCNTs effectively endows the HAHP@SWCNT nanocomposites with improved cycling stability and fast charge-discharge rates. As a result, the HAHP@SWCNT nanocomposite cathode shows a high specific capacity (320.4 mA h g-1 at 100 mA g-1), excellent cycling stability (800 cycles; 290 mA h g-1 at 100 mA g-1, capacity retained 91%) and outstanding rate performance (235 mA h g-1 at 2000 mA g-1, 76% capacity retention versus 50 mA g-1). This work provides a strategy to combine the macromolecular structural design and micromorphology control of electrode materials for obtaining organic polymer cathodes for high-performance LIBs.

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Lithiation-induced controllable vacancy engineering for developing highly active Ni3Se2 as a high-rate and large-capacity battery-type cathode in hybrid supercapacitors Yinna He, Ting Liu, Jiangnan Song, Yiwei Wang, Yuxiao Zhang, Jie Feng, Alan Meng, Guicun Li, Lei Wang, Jian Zhao, Zhenjiang Li 2023, 78(3): 37-46.  DOI: 10.1016/j.jechem.2022.11.027 Abstract ( 12 )   PDF (3097KB) ( 8 )   The poor rate capability and low capacity are huge barriers to realize the commercial applications of battery-type transition metal compounds (TMCs) cathode. Herein, numerous Se vacancy defects are introduced into the Ni3Se2 lamellas by pre-lithiation technique, which can be acted as a novel class of battery-type cathode for hybrid supercapacitors. Appropriately modulating the contents of the pre-embedded lithium (Li) ions can induce a controllable vacancy content in the series of as-prepared prod-ucts, effectively endowing a fast reaction kinetic and high activity for the cathode. Benefiting from the distinct design, the optimized cathode (Li2-Ni3Se2) presents a high specific capacity of 236 mA h g-1 at 1Ag-1, importantly, it can still possess 117 mA h g-1 when the current density is increased up to 100 Ag-1, exhibiting relatively high rate capability. It is much superior to other battery-type TMC cathodes reported in previous studies. Moreover, the cathode also shows the excellent cycling stability with 92%capacity retention after 3,000 cycles. In addition, a hybrid supercapacitor (HSC) is assembled with the obtained Li2-Ni3Se2 as the cathode and active carbon (AC) as the anode, which delivers a high energy den-sity of 77 W h kg-1 at 4 kW kg-1 and long-term durability (90% capacitance retention after 10,000 cycles). Therefore, the strategy not only provides an effective way to realize the controllable vacancy content in TMCs for achieving high-performance cathodes for HSC, but also further promotes their large-scale appli-cations in the energy storage fields.

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Dual-interlayers constructed by Ti3C2Tx/ionic-liquid for enhanced performance of solid garnet batteries Xi Wang, Yong Wang, Yiyu Wu, Yunmiao Fan, Yang Tian 2023, 78(3): 47-55.  DOI: 10.1016/j.jechem.2022.11.052 Abstract ( 8 )   PDF (2503KB) ( 5 )   Li6.4La3Zr1.4Ta0.6O12 (LLZTO) solid garnet-type electrolyte has been widely reported due to its outstanding safety and electrochemical stability. However, the inherent rigidity and brittleness of LLZTO lead to poor contact with anode/cathode and the operation failure of full cells. Herein, the dual-interlayers are con-structed as the fast interfacial ion-migration channel by using Ti3C2Tx (MXene, Tx is -O, -OH, -F) with trace ionic liquid (IL), which promote the intimate contact between LLZTO and anode/cathode and sup-press Li-dendrites growth. Notably, IL can wet the cathode to promote intimate interface contact and be decomposed into some inorganic compounds (such as Li3N, LiF, and Li2Sx), resulting in reduced interfacial resistance and fast Li-ion transportation. Consequently, in the prepared Li-symmetric cell, the interfacial resistance on the anode side plunges to 33.1Ω cm-2, and stably maintains over 1000 h without short cir-cuit at 0.05 mA cm-2. The full cell of Li|LiFePO4 delivers a high initial capacity of 158.52 mA h g-1 and outstanding retention of 90.18% after 100 cycles at 60 C and 0.2 C. Our work provides an efficient strat-egy to design dual-interlayers between LLZTO and anode/cathode for the interfacial modification to enhance the performance of solid garnet batteries.

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Activation of 2D MoS2 electrodes induced by high-rate lithiation processes Tianzhu Liu, Georgian Melinte, Oleksandr Dolotko, Michael Knapp, Beatriz Mendoza-Sánchez 2023, 78(3): 56-70.  DOI: 10.1016/j.jechem.2022.11.007 Abstract ( 10 )   PDF (3061KB) ( 5 )   MoS2 is a highly promising material for application in lithium-ion battery anodes due to its high theoret-ical capacity and low cost. However, problems with a fast capacity decay over cycling, especially at the first cycles, and poor rate performance have deterred its practical implementation. Herein, electrodes comprised solely of few-layers 2D MoS2 nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods. The long-standing controversy questioning the reversibility of conversion processes of MoS2-based electrodes was addressed. Raman studies revealed that, in 2D MoS2 electrodes, conversion processes are indeed reversible, where nanostructure played a key role. Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a contin-uously increasing capacity after ca. 100-200 cycles. This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes. Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability, as compared to the corresponding pristine electrodes, and to MoS2 electrodes previously reported. Herein, we have devised a methodology to overcome the problem of cycling stability of 2D MoS2 electrodes. Moreover, activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials, or combinations thereof, strategically com-bining chemistries to engineer electrodes of superior energy storage properties.

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Diluent decomposition-assisted formation of LiF-rich solid-electrolyte interfaces enables high-energy Li-metal batteries Junbo Zhang, Haikuo Zhang, Ruhong Li, Ling Lv, Di Lu, Shuoqing Zhang, Xuezhang Xiao, Shujiang Geng, Fuhui Wang, Tao Deng, Lixin Chen, Xiulin Fan 2023, 78(3): 71-79.  DOI: 10.1016/j.jechem.2022.11.013 Abstract ( 29 )   PDF (2305KB) ( 19 )   Passivation by the inorganic-rich solid electrolyte interphase (SEI), especially the LiF-rich SEI, is highly desirable to guarantee the durable lifespan of Li metal batteries (LMBs). Here, we report a diluent with the capability to facilitate the formation of LiF-rich SEI while avoiding the excess consumption of Li salts. Dissimilar to most of reported inert diluents, heptafiuoro-1-methoxypropane (HM) is firstly demon- strated to cooperate with the decomposition of anions to generate LiF-rich SEI via releasing F-containing species near Li surface. The designed electrolyte consisting of 1.8 M LiFSI in the mixture of 1,2-dimethoxyethane (DME)/HM (2:1 by vol.) achieves excellent compatibility with both Li metal anodes (Coulombic efficiency 99.8%) and high-voltage cathodes (4.4 V LiNi0.8Mn0.1Co0.1O2 (NMC811) and 4.5 V LiCoO2 (LCO) vs Li+/Li). The 4.4 V Li (20 µm)||NMC811 (2.5 mA h cm-2) and 4.5 V Li (20 µm)||LCO (2.5 mA h cm-2) cells achieve capacity retentions of 80% over 560 cycles and 80% over 505 cycles, respec- tively. Meanwhile, the anode-free pouch cell delivers an energy density of 293 W h kg-1 initially and retains 70% of capacity after 100 deep cycles. This work highlights the critical impact of diluent on the SEI formation, and opens up a new direction for designing desirable interfacial chemistries to enable high-performance LMBs.

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Highly improved cyclic stability of Ni-rich/Li batteries with succinic anhydride as electrolyte additive and underlying mechanism Shu Yang, Guanjie Li, Xiaoyan Lin, Changyong Mo, Xianggui Zhou, Lijiao Quan, Kuan Zhou, Suli Li, Hai Wang, Weishan Li 2023, 78(3): 80-90.  DOI: 10.1016/j.jechem.2022.11.042 Abstract ( 35 )   PDF (4037KB) ( 14 )   Lithium-metal battery based on Ni-rich cathode provides high energy density but presents poor cyclic stability due to the unstable electrode/electrolyte interfaces on both cathode and anode. In this work, we report a new strategy to address this issue. It is found that the cyclic stability of Ni-rich/Li battery can be significantly improved by using succinic anhydride (SA) as an electrolyte additive. Specifically, the capacity retention of LiNi0.8Co0.1Mn0.1O2 (NCM811)/Li cell is improved from 14% to 83% after 200 cycles at 1 C between 3.0 and 4.35 V by applying 5% SA. The underlying mechanism of SA contribution is understood by comparing the effects of malic anhydride (MA) and citraconic anhydride (CA), both of which share a similar molecular structure to SA but show different effects. On anode side, SA can but MA and CA cannot form a protective solid electrolyte interphase (SEI) on Li anode. On cathode side, three anhydrides can suppress the formation of hydrogen fiuoride from electrolyte oxidation decomposition, but SA behaves best. Typically, MA shows adverse effects on the interface stability of Li anode and NCM811cathode, which originates from its high acidity. Though the acidity of MA can be mitigated by substituting a methyl for one H atom at its C=C bond, the substituent CA cannot compete with SA in cyc-lic stability improvement of the cell, because the SEI resulting from CA is not as robust as that from SA, which is related to the binding energy of the SEI components. This understanding reveals the importance of the electrolyte acidity on the Ni-rich cathode and the robustness of the SEI on Li anode, which is helpful for rationally designing new electrolyte additives to further improve the cyclic stability of high-energy-density Ni-rich/Li batteries.

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Superior lithium storage performance in MoO3 by synergistic effects: Oxygen vacancies and nanostructures Xueyang Hou, Miao Ruan, Lijiao Zhou, Jianchun Wu, Bicheng Meng, Wenlong Huang, Kenan Zhong, Kai Yang, Zhao Fang, Keyu Xie 2023, 78(3): 91-101.  DOI: 10.1016/j.jechem.2022.11.011 Abstract ( 12 )   PDF (3365KB) ( 6 )   Molybdenum trioxide (MoO3) has recently attracted wide attention as a typical conversion-type anode of Li-ion batteries (LIBs). Nevertheless, the inferior intrinsic conductivity and rapid capacity fading during charge/discharge process seriously limit large-scale commercial application of MoO3. Herein, the density function theory (DFT) calculations show that electron-proton co-doping preferentially bonds symmetric oxygen to form unstable HxMoO3. When the -OH- group in HxMoO3 is released into the solution in the form of H2O, it is going to form MoO3-x with lower binding energy. By the means of both electron-proton co-doping and high-energy nanosizing, oxygen vacancies and nanofiower structure are introduced into MoO3 to accelerate the ion and electronic diffusion/transport kinetics. Benefitting from the promotion of ion diffusion kinetics related to nanostructures, as well as both the augmentation of active sites and the improvement of electrical conductivity induced by oxygen vacancies, the MoO3-x/nanofiower struc-tures show excellent lithium-ion storage performance. The prepared specimen has a high lithium-ion storage capacity of 1261 mA h g-1 at 0.1 A g-1 and cyclic stability (450 cycle), remarkably higher than those of previously reported MoO3-based anode materials.

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Research perspectives for catalytic valorization of biomass Weiping Deng, Ye Wang 2023, 78(3): 102-104.  DOI: 10.1016/j.jechem.2022.11.019 Abstract ( 16 )   PDF (386KB) ( 10 )

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Propelling polysulfide redox by Fe3C-FeN heterostructure@nitrogendoped carbon framework towards high-efficiency Li-S batteries Mengdi Zhang, Jiawei Mu, Yanan Li, Yuanyuan Pan, Zhiliang Dong, Bei Chen, Shiwei Guo, Wenhan Yuan, Haiqiu Fang, Han Hua, Mingbo Wu 2023, 78(3): 105-114.  DOI: 10.1016/j.jechem.2022.11.026 Abstract ( 15 )   PDF (3186KB) ( 14 )   Lithium-sulfur (Li-S) batteries hold great promise in next-generation high-energy-density energy storage systems, but the intractable shuttle effect and the sluggish redox kinetics of polysulfides hinder the prac-tical implementation of Li-S batteries. Here, heterostructured Fe3C-FeN nanoparticles dotted in the three-dimensional-ordered nitrogen-doped carbon framework (Fe3C-FeN@NCF) were synthesized by molecular engineering combined with heterointerface engineering, and were applied to regulate the immobilization-diffusion-conversion behavior of polar polysulfides. It is experimentally and theoretically demonstrated that the heterointerface between Fe3C and FeN exhibits high sulfiphilicity and high elec-tronic/ionic conductivity, thus effectively capturing polysulfides and accelerating the bidirectional con-version of sulfur species. Meanwhile, the holey carbon framework functions as the scaffold to highly disperse binary nanoparticles, ensuring the sufficient exposure of active sites and the easy accessibility for lithium ions and electrons. By virtue of these synergistic merits, the Li-S batteries based on Fe3C-FeN@NCF-modified separators afford excellent electrochemical performances including a high rate capacity of 858 mA h g-1 at 2 C and a low capacity decay rate of 0.07% per cycle after 800 cycles at 1 C. This work provides inspiration for the design of heterostructured compounds and sheds light on the potential of heterostructure in high-efficiency Li-S batteries.

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Effect of homojunction structure in boosting sodium-ion storage: The case of MoO2 Sheng Li, Wei Zhang, Yingxue Cui, Jianmin Ma, Hong-Jie Peng, Jun Li, Xianhu Liu, Dickon H. L. Ng, Xinyan Liu, Jiabiao Lian 2023, 78(3): 115-122.  DOI: 10.1016/j.jechem.2022.11.020 Abstract ( 6 )   PDF (2116KB) ( 4 )   High-efficiency sodium-ion batteries (SIBs) are in great demand for energy storage applications, which are dominated by the Na+ storage performance of electrode materials. Here, a one-pot solvothermal method is developed to construct amorphous/crystalline MoO2 (a/c-MoO2) homojunction for boosting Na+ storage. Theoretical simulations signify that electrons redistribute at the homogenous interface of a/c-MoO2, resulting in an inbuilt driving force to easily adsorb charge carriers and promote the elec-tron/ion transfer ability. Relying on its crystallographic superiorities, the a/c-MoO2 homojunction with high Na adsorbability (-1.61 eV) and low Na diffusion energy barrier (0.519 eV) achieves higher capacity (307 mA h g-1 at 0.1 A/g), better rate capability and cycling stability than either a-MoO2 or c-MoO2 coun-terpart. Combining in-situ X-ray diffraction (XRD) and ex-situ X-ray photoelectron spectroscopy (XPS) techniques, the ‘adsorption-insertion-conversion' mechanism is well established for Na+ storage of MoO2. Our work opens new opportunities to optimize electrode materials via crystallographic engineer-ing for efficient Na+ storage, and helps to better understand the effects of homojunction structure in enhanced electrochemical performance.

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Improving the electrochemical performance of a-MoO3 electrode using aluminium trifluoromethanesulfonate water-in-salt electrolyte Ayman E. Elkholy, Timothy T. Duignan, Ruth Knibbe, Xiu Song Zhao 2023, 78(3): 123-134.  DOI: 10.1016/j.jechem.2022.11.015 Abstract ( 15 )   PDF (2436KB) ( 4 )   Orthorhombic molybdenum trioxide (a-MoO3) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes. We investigated the charge-storage performance of a-MoO3 electrode in aluminium trifiuoromethanesulfonate (Al(OTf)3)-based salt-in-water electrolyte (SiWE) and water-in-salt electrolyte (WiSE). It was found that a-MoO3 electrode exhibits significantly different cycling stabilities in both electrolytes with capacity retentions of 8% using the former and 87% using the latter. This is because a-MoO3 electrode maintains its crystal structure upon cycling in WiSE, but experiences substantial structural collapses and partial dissolution upon cycling in SiWE. This behaviour was inferred from both operando electrogravimetry and ex situ analyses. Research results suggest that the predominant charge-storage mechanism in a-MoO3 electrode using WiSE is the interca-lation of protons produced from electrolyte hydrolysis with some contribution from surface pseudoca-pacitance enabled by Al3+ ions. A two-volt full cell fabricated from a-MoO3 electrode as anode and copper hexacyanoferrate (CuHCF) electrode as cathode using WiSE delivers volumetric and gravimetric energies of 10.4 Wh/L and 26.5 Wh/kg, respectively, with 78% capacity retention after 2500 cycles. This study provides an insightful understanding of the electrochemical performance of a-MoO3 electrode in Al(OTf)3-based electrolytes.

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Insight into the ammonia torrefaction and pyrolysis system of cellulose: Unraveling the evolution of chemical structure and nitrogen migration mechanism Shanjian Liu, An Zhao, Jia Liu, Mengqian Yin, Fupeng Huang, Dongmei Bi 2023, 78(3): 135-147.  DOI: 10.1016/j.jechem.2022.11.046 Abstract ( 22 )   PDF (4010KB) ( 14 )   This study aimed to investigate the mechanism of nitrogen doping, migration, and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose. The results showed that the ammonia torrefaction pretreatment could significantly optimize the distribution of nitrogen and oxygen elements in cellulose. The carbon skeleton first captured the active nitrogenous radicals to form -NHn-N, and pyridine-N and pyrrole-N originated from the conversion of -NHn-N. The existence of C=O played a major role in the immobilization of nitrogen. The nitrogen in bio-oil exists mainly in the form of five- and six-membered heterocycles. The correlation analysis showed that the main precursors for the formation of nitrogenous heterocyclic compounds were five-membered O-heterocyclic compounds. Finally, the product distribution characteristics in the torrefaction-pyrolysis systems were summarized, and the nitrogen doping and conversion mechanisms were proposed. This study expanded the boundaries of cellulose pretreatment and the production of high-value chemicals.

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Superior electrocatalytic negative electrode with tailored nitrogen functional group for vanadium redox flow battery Min Gu Kang, Wook Ahn, Joonhee Kang, Shin Ae Song, Kiyoung Kim, Ju Young Woo, Yong-Cheol Jeong, Bonwook Koo, Dae Soo Jung, Sung Nam Lim 2023, 78(3): 148-157.  DOI: 10.1016/j.jechem.2022.11.022 Abstract ( 11 )   PDF (2055KB) ( 8 )   Development of electrodes with high electrocatalytic activity and stability is essential for solving prob-lems that still restrict the extensive application of vanadium redox fiow batteries (VRFBs). Here, we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen func-tional groups, such as newly formed nitro and pyridinic-N transformed to pyridonic-N, from the pre-nitrogen-doped electrode. It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups (tailored nitrogen-doped graphite felt, TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer. Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption, charge transfer, and bond formation with the vanadium species, which is consistent with expermental results. In addition, the V2+/V3+ redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density func-tional theory (DFT) results. When TNGF was applied to a VRFB, it enabled enhanced-electrolyte utilization and energy efficiencies (EE) of 57.9% and 64.6%, respectively, at a current density of 250 mA cm-2. These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinic-N groups. Interestingly, TNGF-based VRFB still operated with an EE of 59% at a high current density of 300 mA cm-2. The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm-2. The results of this study sug-gest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electro-chemical performance of VRFBs.

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Alternatingly stacked thin film electrodes-based compact aqueous hybrid electrochemical capacitors for hundred-volts AC line filtering Lixia Wang, Lingyu Zhao, Meirong Song, Lixia Xie, Xiaopeng Wang, Xin Li, Yanjie Huang, Min Wei, Qiu Jin, Xianglong Meng, Yang Zhao 2023, 78(3): 158-168.  DOI: 10.1016/j.jechem.2022.11.055 Abstract ( 11 )   PDF (2000KB) ( 6 )   Filtering capacitor with compact configuration and a wide range of operating voltage has been attracting increasing attention for the smooth conversion of the electric signal in modern circuits. Lossless integra-tion of capacitor units can be regarded as one of the efficient ways to achieve a wider voltage range, which has not yet been fully conquered due to the lack of rational designs of the electrode structure and integration technology. This study presents an alternatingly stacked assemble technology to conve-niently fabricate compact aqueous hybrid integrated filtering capacitors on a large scale, in which a unit consists of rGO/MXene composite film as a negative electrode and PEDOT:PSS based film as a positive electrode. Benefiting from the synergistic effect of rGO and MXene components, and morphological char-acteristics of PEDOT:PSS, the capacitor unit exhibits outstanding AC line filtering with a large areal speci-fic energy density of 1,015 lFV2 cm-2 (0.28 lWh cm-2) at 120 Hz. After rational integration, the assembled capacitors present compact/lightweight configuration and lossless frequency response, as refiected by almost constant resistor-capacitor time constant of 0.2 ms and dissipation factor of 15% at 120 Hz, identical to those of the single capacitor unit. Apart from standing alone steadily on a fiower, a small volume (only 8.1 cm3) of the integrated capacitor with 70 units connected in series achieves hundred-volts alternating current line filtering, which is superior to most reported filtering capacitors with sandwich configuration. This study provides insight into the fabrication and application of com-pact/ultralight filtering capacitors with lossless frequency response, and a wide range of operating voltage.

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Superior oxygen electrocatalyst derived from metal organic coordination polymers by instantaneous nucleation and epitaxial growth for rechargeable Li-O2 battery Dongdong Li, Jinbiao Chen, Yingtong Chen, Yian Wang, Yanpeng Fu, Minhua Shao, Zhicong Shi 2023, 78(3): 169-177.  DOI: 10.1016/j.jechem.2022.11.048 Abstract ( 10 )   PDF (2774KB) ( 4 )   Rechargeable aprotic Li-O2 batteries have attracted increasing attention due to their extremely high capacity, and it is very important to design appropriate strategies to synthesize efficient catalysts used as oxygen cathode. In present work, we present an expedient ‘‘instantaneous nucleation and epitaxial growth” (INEG) synthesis strategy for convenient and large-scale synthesis of ultrafine MOCPs nanopar-ticles (size 50-100 nm) with obvious advantages such as fast synthesis, high yields, low costs and reduced synthetic steps. The bimetallic Ru/Co-MOCPs are further pyrolyzed to obtain bimetallic Co-and low content of Ru-based nanoparticles embedded within nitrogen-doped carbon (Ru/Co@NAC) as an efficient catalyst used in Li-O2 battery. The Ru/Co@NAC provides porous carbon framework for the ion transportation and O2 diffusion, and has large amounts of metal/nonmetal sites as active site to pro-mote the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) in Li-O2 batteries. As a con-sequence, a high discharge specific capacity of 15246 mA h g-1 at 250 mA g-1, excellent rate capability at different current densities, and stable overpotential during cycling, are achieved. This work opened up a new understanding for the industrialized synthesis of ultrafine catalysts for Li-O2 batteries with excellent structural characteristics and electrochemical performance.

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Tailored deep-eutectic solvent method to enable 3D porous iron fluoride bricks for conversion-type lithium batteries Chuanzhong Lai, Keyi Chen, Yongjian Zheng, Junwei Meng, Jiulin Hu, Chilin Li 2023, 78(3): 178-187.  DOI: 10.1016/j.jechem.2022.11.004 Abstract ( 13 )   PDF (2762KB) ( 10 )   Conversion-type fiuoride cathode can provide considerable energy density for Li batteries, however its scalable and facile synthesis strategies are still lacking. Here, a novel Fe-based deep eutectic solvent com-posed of nitrite and methylsulfonylmethane is proposed as both the reaction medium and precursor to synthesize O-doped FeF3 porous bricks. This method is cheaper, safe, mildly operable, environmentally friendly and recyclable for non-fiuorinated metal cations. The homogenization of charge and mass trans-port in cathode network effectively mitigates the volume extrusion and electrode coarsening even for the micro-sized monolithic particles. The Co-solvation modulated fiuoride cathode delivers high reversible capacity in a wide temperature range (486 and 235 mA h g-1 at 25 C and -20 C respectively), excellent rate performance (312 mA h g-1 at 1000 mA g-1), corresponding to an energy density as high as 672.1 W h kg-1 under a power density of 2154.3 W kg-1. The successful operation of fiuoride pouch-cell with a capacity exceeding 450 mA h g-1 (even under thin Li foil and lean electrolyte conditions) indi-cates its potentiality of commercial application.

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Glass-compatible and self-powered temperature alarm system by temperature-responsive organic manganese halides via backward energy transfer process Pengfei Xia, Fan Liu, Yuru Duan, Xuefang Hu, Changgui Lu, Shuhong Xu, Chunlei Wang 2023, 78(3): 188-194.  DOI: 10.1016/j.jechem.2022.09.036 Abstract ( 9 )   PDF (1417KB) ( 4 )   A pioneering glass-compatible transparent temperature alarm system self-powered by luminescent solar concentrators (LSCs) is raeported. Single green-emitted organic manganese halides (OMHs) of PEA2MnBr2I2, which has a unique temperature-dependent backward energy transfer process from self-trapped state to 4T1 energy level of Mn, is used for triggering the temperature alarm. The LSC with red-emitted CsPbI3 perovskite-polymer composite films on the glass substrate is used for power supply. The spectrally separated nature between the green-emitted OMHs for temperature alarm and red-emitted CsPbI3 in LSC for power supply allows for probing the signal light of temperature-responsive OMHs without the interference of LSCs, making it possible to calibrate the temperature visually just by a self-powered brightness detection circuit with LED indicators. Taking advantage of LSC without hot spot effects plaguing the solar cells, as-prepared temperature alarm system can operate well on both sunny and cloudy day.

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Construction of N, O co-doped carbon anchored with Co nanoparticles as efficient catalyst for furfural hydrodeoxygenation in ethanol Hui Yang, Hao Chen, Wenhua Zhou, Haoan Fan, Chao Chen, Yixuan Sun, Jiaji Zhang, Sifan Wang, Teng Guo, Jie Fu 2023, 78(3): 195-202.  DOI: 10.1016/j.jechem.2022.11.037 Abstract ( 12 )   PDF (1853KB) ( 10 )   Hydrodeoxygenation of furfural (FF) into 2-methylfuran (MF) is a significant biomass utilization route. However, designing efficient and stable non-noble metal catalyst is still a huge challenge. Herein, we reported the N, O co-doped carbon anchored with Co nanoparticles (Co-SFB) synthesized by employing the organic ligands with the target heteroatoms. Raman, electron paramagnetic resonance (EPR), electro-chemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS) characterizations showed that the co-doping of N and O heteroatoms in the carbon support endows Co-SFB with enriched lone pair electrons, fast electron transfer ability, and strong metal-support interaction. These electronic properties resulted in strong FF adsorption as well as lower apparent reaction activation energy. At last, the obtained N, O co-doped Co/C catalyst showed excellent catalytic activity (nearly 100 mol% FF conver-sion and 94.6 mol% MF yield) and stability for in-situ dehydrogenation of FF into MF. This N, O co-doping strategy for the synthesis of highly efficient catalytic materials with controllable electronic state will pro-vide an excellent opportunity to better understand the structure-function relationship.

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Nickel single atom overcoordinated active sites to accelerate the electrochemical reaction kinetics for Li-S cathode Juan Zhu, Xinyue Wang, Tian Ke, Mingji Jia, Biyu Jin, Yuanyuan Li, Qiwei Yang, Lanhui Ren, Yongyuan Ren, Dangguo Cheng, Jianguo Lu, Xiang Gao, Qinggang He, Yang Hou, Xiaoli Zhan, Qinghua Zhang 2023, 78(3): 203-210.  DOI: 10.1016/j.jechem.2022.08.041 Abstract ( 14 )   PDF (2050KB) ( 4 )   Lithium-sulfur (Li-S) batteries with high theoretical energy density are promising advanced energy stor-age devices. However, shuttling of dissolute lithium polysulfide (LiPSs) and sluggish conversion kinetics impede their applications. Herein, single nickel (Ni) atoms on two-dimensional (2D) nitrogen(N)-doped carbon with Ni-N4-O overcoordinated structure (SANi-N4-O/NC) are prepared and firstly used as a sulfur host of Li-S batteries. Due to the efficient polysulfides traps and highly LiPSs conversion effect of SANi-N4-O/NC, the electrochemical performance of Li-S batteries obviously improved. The batteries can well oper-ate even under high sulfur loading (5.8 mg cm-2) and lean electrolyte (6.1 µLmg-1) condition. Meanwhile, density functional theory (DFT) calculations demonstrate that Ni single atom's active sites decrease the energy barriers of conversion reactions from Li2S8 to Li2S due to the strong interaction between SANi-N4-O/NC and LiPSs. Thus, the kinetic conversion of LiPSs was accelerated and the shuttle effect is suppressed on SANi-N4-O/NC host. This study provides a new design strategy for a 2D structure with single-atom overcoordinated active sites to facilitate the fast kinetic conversion of LiPSs for Li-S cathode.

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Modulating surface oxygen species via facet engineering for efficient conversion of nitrate to ammonia Wenye Zhong, Zhiheng Gong, Zuyun He, Nian Zhang, Xiongwu Kang, Xianwen Mao, Yan Chen 2023, 78(3): 211-221.  DOI: 10.1016/j.jechem.2022.11.024 Abstract ( 18 )   PDF (2449KB) ( 10 )   Electrochemical reduction of nitrate, a common pollutant in aquatic environment, to valuable ammonia (NO3-RR) using renewably-sourced electricity has attracted widespread interests, with past efforts mainly focused on designing electrocatalysts with high activity and selectivity. The detailed correlation between catalyst properties and NO3-RR kinetics, nevertheless, is still not fully understood. In this work, we mod-ulate the surface oxygen species of Cu2O via facet engineering, and systematically study the impact of these oxygen species on the NO3-RR activity. Combining advanced spectroscopic techniques, density func-tional theory calculations and molecular dynamics simulations, we find that while oxygen vacancies on Cu2O (111) surface promote the adsorption of reactants and reaction intermediates, hydroxyl groups effectively inhibit the side reaction of hydrogen evolution and facilitate the hydrogenation process of NO3-RR. These two effects work in concert to render Cu2O (111) facet the highest NO3-RR activity relative to those from other facets. Our study provides critical insights into the synergistic effect of exposed facets and surface oxygen species on heterogeneous catalysis, and offers a generalizable, facet engineering-based strategy for improving the performance of a variety of electrocatalysts important for renewable energy conversion.

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A high-capacity viologen-based anolyte for high energy density neutral pH aqueous redox-flow batteries Anubhav Kumar, Bijay P. Tripathi 2023, 78(3): 222-231.  DOI: 10.1016/j.jechem.2022.11.053 Abstract ( 14 )   PDF (2403KB) ( 4 )   Redox-fiow batteries (RFBs) are a promising energy storage technology with remarkable scalability and safety for storing vast amounts of renewable energy and mitigating output fiuctuations of renewable power grids. We demonstrate a neutral pH aqueous RFB using a custom-designed 1',1''',1'''''-(benzene-1,3,5-triyltris(methylene))tris(1-(3-(trimethyl ammonio) propyl)-[4'',4'''-bipyridine]-1,1'-diium) nonachloride (BTTMPB) as a 3 e- storage anolyte. The custom design with the high polarization in charge density has led to the excellent water solubility of 4.0 M in H2O (321.6 A h L-1) and 2.4 M in 2.0 M NaCl (192.9 A h L-1). The density functional theory (DFT) calculations and electrochemical experiments have shown 3 e- storage response of BTTMPB with a diffusion coefficient of 3.1 × 10-6 cm2 s-1 and rate con-stant of 1.6 × 10-2 cm s-1 for the first reduction process. The synthesized anolyte was paired with (Ferrocenylmethyl)trimethylammonium chloride (FcNCl) as catholyte enabling a 0.92 V aqueous RFB with 125.9 W h L-1 theoretical energy density. The aqueous RFB has an excellent cycling performance from 10-30 mA cm-2, energy efficiency up to 80%, capacity retention of ~99.96% per cycle at 20 mA cm-2, and a high demonstrated energy density of 29.1 W h L-1.

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An integrated machine learning model for accurate and robust prediction of superconducting critical temperature Jingzi Zhang, Ke Zhang, Shaomeng Xu, Yi Li, Chengquan Zhong, Mengkun Zhao, Hua-Jun Qiu, Mingyang Qin, X.-D. Xiang, Kailong Hu, Xi Lin 2023, 78(3): 232-239.  DOI: 10.1016/j.jechem.2022.11.047 Abstract ( 13 )   PDF (1145KB) ( 4 )   Discovering new superconductors via traditional trial-and-error experimental approaches is apparently a time-consuming process, and the correlations between the critical temperature (Tc) and material features are still obscure. The rise of machine learning (ML) technology provides new opportunities to speed up inefficient exploration processes, and could potentially uncover new hints on the unclear correlations. In this work, we utilize open-source materials data, ML models, and data mining methods to explore the correlation between the chemical features and Tc values of superconducting materials. To further improve the prediction accuracy, a new model is created by integrating three basic algorithms, showing an enhanced accuracy with the coefficient of determination (R2) score of 95.9 % and root mean square error (RMSE) of 6.3 K. The average marginal contributions of material features towards Tc values are esti-mated to determine the importance of various features during prediction processes. The results suggest that the range thermal conductivity plays a critical role in Tc prediction among all element features. Furthermore, the integrated ML model is utilized to screen out potential twenty superconducting mate-rials with Tc values beyond 50.0 K. This study provides insights towards Tc prediction to accelerate the exploration of potential high-Tc superconductors.

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Investigating TEP as a greener alternative to NMP in Ni-rich cathode fabrication Changlong Chen, Vignyatha Reddy Tatagari, Hao Lin, Leon Shaw 2023, 78(3): 240-245.  DOI: 10.1016/j.jechem.2022.12.006 Abstract ( 25 )   PDF (897KB) ( 16 )   In the past decade, the surging demand for portable electronics, electric vehicles, and stationary energy storage grids has triggered a noticeable rise in the production of Li-ion batteries (LIBs). However, this swift rise is now hindered by relying on the use of N-methyl-2-pyrrolidone (NMP), a repro-toxic solvent, in the current cathode processing of LIBs. To overcome this challenge, here we have investigated triethyl phosphate (TEP) as a greener alternative to NMP. The compatibility with polyvinylidene fiuoride (PVDF) binder, the slurry rheology, the electrode morphology and cell performance with Ni-rich cathodes are characterized. The results show that TEP-based samples possess indistinguishable characteristics in all aspects studied when compared with NMP, revealing that TEP is a promising substitute for NMP in pro-cessing Ni-rich cathodes. It is anticipated that this green solvent, TEP, will draw attention from industry in the real-world LIB application in the future.

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How to stabilize standard perovskite solar cells to withstand operating conditions under an ambient environment for more than 1000 hours using simple and universal encapsulation Nikolai A. Belich, Andrey A. Petrov, Pavel A. Ivlev, Natalia N. Udalova, Alla A. Pustovalova, Eugene A. Goodilin, Alexey B. Tarasov 2023, 78(3): 246-249.  DOI: 10.1016/j.jechem.2022.12.010 Abstract ( 20 )   PDF (1165KB) ( 22 )   We introduce a simple and universal scalable encapsulation strategy for perovskite solar cells based on thermal vacuum evaporation of MgF2 or MoO3-x capping layer followed by sealing the device with glass and UV-curable polymer. The proposed encapsulation method is beneficial to most of the other known encapsulation approaches being fully harmless to perovskite and transporting layers and processible at room temperature. Vacuum deposition of the capping layer promotes efficient removal of water, oxygen and organic solvent residuals from the device prior to sealing and could be easily performed using stan-dard equipment for metal electrode deposition. The proposed strategy is transferrable to any lab-scale perovskite solar cell prototypes regardless of their geometry and architecture and results in excellent sta-bility of the devices in ambient air and long operating conditions. Upon the 1000 hours stability test at ambient air (30%-60% RH), the cells preserved 92.9% of their initial efficiency on average under 1 Sun illu-mination at constant maximum power point tracking (MPPT, ISOS-L-1) and over 96% under storage in the dark (ISOS-D-1), thus evidencing for the high effectiveness of the proposed encapsulation approach.

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A strategic way of high-performance energy storage device development with environmentally viable ‘‘Water-in-salt” electrolytes Prakas Samanta, Souvik Ghosh, Aniruddha Kundu, Pranab Samanta, Naresh Chandra Murmu, Tapas Kuila 2023, 78(3): 250-252.  DOI: 10.1016/j.jechem.2022.11.045 Abstract ( 13 )   PDF (4009KB) ( 6 )   Development of cost-effective and environmental friendly energy storage devices (ESDs) has attracted widespread attention in recent scenario of energy research. Recently, the environmentally viable ‘‘water-in-salt” (WiS) electrolytes has received significant interest for the development of advanced high performance ESDs. The WiS electrolyte exhibits wide electrochemical stability window (ESW), high-safety, non-fiammability and superior electrochemical performance compared to the conventional ‘‘salt-in-water” electrolytes. This review aims to provide a comprehensive discussion on WiS electrolyte based on theoretical, electrochemical and physicochemical characteristics. A strategic way for the usage of WiS electrolyte in rechargeable metal-ion batteries and supercapacitors with potentially improved electrochemical performance has been reviewed systematically. This review also discussed the unique advantages of WiS electrolytes as well as the future scope and challenges.

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Review of preferentially selective lithium extraction from spent lithium batteries: Principle and performance Zhe Gao, Meiting Huang, Liming Yang, Yufa Feng, Yuan Ding, Penghui Shao, Xubiao Luo 2023, 78(3): 253-261.  DOI: 10.1016/j.jechem.2022.11.061 Abstract ( 24 )   PDF (1819KB) ( 8 )   Lithium, as the lightest and lowest potential metal, is an ideal ‘‘battery metal” and the core strategic metal of the new energy industry revolution. Recovering lithium from spent lithium batteries (LIBs) has become one of the significant approaches to obtaining lithium resources. At present, the lithium extraction being generally placed at the last step of the spent LIBs recovery process has puzzles such as high acid consumption, low Li recovery purity and low recovery efficiency. Selective lithium extraction at the first step of the recovery process can effectively solve those puzzles. Since lithium leaching is a non-spontaneous reaction requiring additional energy to achieve, it is found that these methods can be divided into five ways according to the different types of energy driving the reaction occurring: (i) electric energy driving lithium extraction; (ii) chemical energy driving lithium extraction; (iii) mechan-ical energy driving lithium extraction; (iv) thermal energy driving lithium extraction; (v) other energy driving lithium extraction. Through the analysis of the principle, reaction process and results of recover-ing lithium methods can provide a few directions for scholars' subsequent research. It is necessary to speed up the exploration of the principle of these methods. It is expected that this study could provide a reference for the research on the selective lithium extraction.

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Unraveling the influence of interface defects on antimony trisulfide solar cells Hongyi Chen, Cheng Wang, Shaoying Wang, Ruiming Li, Yan Zeng, Zhe Li, Zhengwei Ou, Qianqian Lin, Jianmin Li, Ti Wang, Hongxing Xu 2023, 78(3): 262-267.  DOI: 10.1016/j.jechem.2022.11.039 Abstract ( 12 )   PDF (1305KB) ( 3 )   Antimony trisulfide (Sb2S3) solar cells suffer from large open circuit voltage deficits due to their intrinsic defects which limit the power conversion efficiency. Thus, it is important to elucidate these defects' ori-gin and defects at the interface. Here, we discover that sulfide radical defects have a significant impact on the performance of Sb2S3 solar cells. Moreover, it has been illustrated that these defects at the CdS/Sb2S3 interface can be reduced by optimizing the deposition process. A trap distribution model is used to quan-tify the defect density at the CdS/Sb2S3 interface. It shows that the interface defects can be reduced by 24% by improving the deposition process. This work reveals the importance of interface defects and guides the future optimization of Sb2S3 solar cells.

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An ensemble learning classifier to discover arsenene catalysts with implanted heteroatoms for hydrogen evolution reaction An Chen, Junfei Cai, Zhilong Wang, Yanqiang Han, Simin Ye, Jinjin Li 2023, 78(3): 268-276.  DOI: 10.1016/j.jechem.2022.11.035 Abstract ( 11 )   PDF (1970KB) ( 1 )   Accurate regulation of two-dimensional materials has become an effective strategy to develop a wide range of catalytic applications. The introduction of heterogeneous components has a significant impact on the performance of materials, which makes it difficult to discover and understand the structure-prop-erty relationships at the atomic level. Here, we developed a novel and efficient ensemble learning clas-sifier with synthetic minority oversampling technique (SMOTE) to discover all possible arsenene catalysts with implanted heteroatoms for hydrogen evolution reaction (HER). A total of 850 doped arsenenes were collected as a database and 140 modified arsenene materials with different doping atoms and doping sites were identified as promising candidate catalysts for HER, with a machine learning pre-diction accuracy of 81%. Based on the results of machine learning, we proposed 13 low-cost and easily synthesized two-dimensional Fe-doped arsenene catalytic materials that are expected to contribute to high-efficient HER. The proposed ensemble method achieved high prediction accuracy, but millions of times faster to predict Gibbs free energies and only required a small amount of data. This study indicates that the presented ensemble learning classifier is capable of screening high-efficient catalysts, and can be further extended to predict other two-dimensional catalysts with delicate regulation.

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Electro-chemo-mechanical design of polymer matrix in composited LiNi0.8Co0.1Mn0.1O2 cathode endows solid-state batteries with superior performance Haolong Jiang, Xieyu Xu, Qingpeng Guo, Hui Wang, Jiayi Zheng, Yuhao Zhu, Huize Jiang, Olesya O. Kapitanova, Valentyn S. Volkov, Jialin Wang, Yaqi Chen, Yongjing Wang, Yu Han, Chunman Zheng, Kai Xie, Shizhao Xiong, Yangyang Liu, Xingxing Jiao 2023, 78(3): 277-282.  DOI: 10.1016/j.jechem.2022.11.059 Abstract ( 15 )   PDF (1354KB) ( 5 )   Nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material has been widely concerned due to its high voltage, high specific capacity and excellent rate performance, which is considered as one of the most promising cathode materials for the next generation of high-energy-density solid-state lithium batteries. However, serious electro-chemo-mechanical degradation of Nickel-rich cathode during cycling, espe-cially at a high voltage (over 4.5 V), constrains their large-scale application. Here, using the multi-physical simulation, highly-conductive polymer matrix with spontaneous stress-buffering effect was uncovered theoretically for reinforcing the electrochemical performance of composited NCM811 cathode through the visualization of uniform concentration distribution of Li-ion coupled with improved stress field inside NCM811 cathode. Thereupon, polyacrylonitrile (PAN) and soft polyvinylidene fiuoride (PVDF) were selected as the polymer matrix to fabricate the composited NCM811 cathode (PVDF-PAN@NCM811) for improving the electrochemical performance of the solid-state NMC811|Li full cells, which can maintain high capacity over 146.2 mA h g-1 after 200 cycles at a high voltage of 4.5 V. Suggestively, designing a multifunctional polymer matrix with high ionic conductivity and mechanical property can buffer the stress and maintain the integrity of the structure, which can be regarded as the door-opening avenue to realize the high electrochemical performance of Ni-rich cathode for solid-state batteries.

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Wide temperature range- and damage-tolerant microsupercapacitors from salt-tolerant, anti-freezing and self-healing organohydrogel via dynamic bonds modulation Cheng Tang, Manni Li, Yaling Wang, Yan Zhang, Yinzhuo Yao, Guolong Wang, Jiamei Liu, Lei Li 2023, 78(3): 283-293.  DOI: 10.1016/j.jechem.2022.11.051 Abstract ( 8 )   PDF (2649KB) ( 3 )   The advance of microelectronics requires the micropower of microsupercapacitors (MSCs) to possess wide temperature- and damage-tolerance beyond high areal energy density. The properties of electrolyte are crucial for MSCs to meet the above requirements. Here, an organohydrogel electrolyte, featured with high salt tolerance, ultralow freezing point, and strong self-healing ability, is experimentally realized via modulating its inner dynamic bonds. Spectroscopic and theoretical analysis reveal that dimethyl sulfox-ide has the ability to reconstruct Li+ solvation structure, and interact with free water and polyvinyl alco-hol chains via forming hydrogen bonds. The organohydrogel electrolyte is employed to build MSCs, which show a boosted energy density, promising wide temperature range- and damage-tolerant ability. These attractive features make the designed organohydrogel electrolyte have great potential to advance MSCs.

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Recent progress and challenges in interdigital microbatteries: Fabrication, functionalization and integration Li Song, Xuting Jin b, Chunlong Dai, Yuyang Han, Jiatao Zhang, Yang Zhao, Zhipan Zhang, Liangti Qu 2023, 78(3): 294-314.  DOI: 10.1016/j.jechem.2022.08.029 Abstract ( 10 )   PDF (5026KB) ( 6 )   Currently, the increasing demands for portable, implantable, and wearable electronics have triggered the interest in miniaturized energy storage devices. Different from conventional energy storage devices, interdigital microbatteries (IMBs) are free of separators and prepared on a single substrate, potentially achieving a short ionic diffusion path and better performance. Meanwhile, they can be easily fabricated and integrated into on-chip miniaturized electronics, holding the promise to provide long-lasting power for advanced microelectronic devices. To date, while many seminal works have been reviewed the topic of microbatteries, there is no work that systematically summarizes the development of IMBs of high energy density and stable voltage platforms from fabrication, functionalization to integration. The cur-rent review focuses on the most recent progress in IMBs, discussing advanced micromachining tech-niques with compatible features to construct high-performance IMBs with smart functions and intelligent integrated systems. The future opportunities and challenges of IMBs are also highlighted, call-ing for more efforts in this dynamic and fast-growing research field.

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Hybrid solid electrolyte interphases formed in conventional carbonate electrolyte enable high-voltage and ultra-stable magnesium metal batteries Yong Xie, Huawei Song, Siyang Ye, Fei Tian, Junjie Xie, Danni Lei, Chengxin Wang 2023, 78(3): 315-324.  DOI: 10.1016/j.jechem.2022.12.011 Abstract ( 9 )   PDF (4830KB) ( 3 )   Magnesium metal batteries are considered as viable alternatives of lithium-ion batteries for their low cost and high capacity of magnesium. Nevertheless, the practical application of magnesium metal batter-ies is extremely challenging due to a lack of suitable electrolyte that can stabilize magnesium metal anode and high-voltage cathode simultaneously. Herein, we found that in-situ formed lithium/magne-sium hybrid electrolyte interphases in conventional LiPF6-containing carbonate-based electrolyte can not only prevent the production of passivation layer on the magnesium metal anode, but also inhibit the oxidation of the electrolyte under high voltage. The symmetric magnesium||magnesium battery can achieve reversible stripping/plating for 1600 and 600 h at 0.02 and 0.1 mA cm-2, respectively. In addition, when coupled with a carbon fiber cathode, the magnesium metal battery exhibited a capacity retention rate of 96.3% for 1000 cycles at a current density of 500 mA g-1 and presented a working volt-age of ~3.1 V. This research paves a new and promising path to the commercialization process of rechargeable magnesium metal batteries.

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Reinforced interface endows the lithium anode with stable cycle at high-temperature of 80℃ Yuhao Zhu, Xieyu Xu, Qingpeng Guo, Yu Han, Haolong Jiang, Huize Jiang, Hui Wang, Pavel V. Evdokimov, Olesya O. Kapitanova, Valentyn S. Volkov, Yongjing Wang, Shizhao Xiong, Chunman Zheng, Kai Xie, Xingxing Jiao, Yangyang Liu 2023, 78(3): 325-332.  DOI: 10.1016/j.jechem.2022.12.004 Abstract ( 15 )   PDF (2348KB) ( 2 )   Embracing ultrahigh theoretical capacity of 3860 mA h g-1 and the lowest reduction potential of 3.04 V (versus standard hydrogen electrode), lithium (Li) is considered as the ‘‘holy grail” material for pursuing higher energy density, of which application has been challenged due to the unstable interface caused by the non-uniform electrodeposition as well as high chemical activity. Operating at higher temperature can be recommended to uniform electrodeposition of Li metal. Nevertheless, the intrinsic side-reaction between Li metal anode and electrolyte is inevitably aggravated and thus fosters the failure of Li metal anode rapidly with uneven electrodeposition. Here, a kind of temperature-tolerated ionic liquid (1-methyl-3-ethylimidazole bis(fiuorosulfonyl)imide/lithium bis(trifiuoromethylsulfonyl)imide, EF/LT) based electrolyte that matrixed with poly(vinylidene fiuoride-hexafiuoropropylene) was designed to maintain the interfacial stabilization of Li metal due to the weak interfacial reaction and uniform elec-trodeposition at high temperature of 80 C. It is the matter that the 660-h cycle with lower polarization is achieved with EF/LT-based electrolyte at temperature of 80 oC and the full cell embraces outstanding cyclic performance, without capacity fading within 100 cycles. Delighting, a door for practical application of Li metal anode for higher energy density as the carbon neutrality progresses in the blooming human society has been opened gradually.

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A universal charge-compensating strategy for high-energy-density pseudocapacitors Baoyi Yin, Jiaqi Zhang, Yuanhui Su, Yu Huan, Liang Hao, Chen Wang, Xun Hu, Tao Wei 2023, 78(3): 333-339.  DOI: 10.1016/j.jechem.2022.12.043 Abstract ( 11 )   PDF (1429KB) ( 2 )   For pseudocapacitive electrode materials (PseEMs), despite much progress having been made in achiev-ing both high power density and high energy density, a general strategy to guide the enhancement of intrinsic capacitive properties of PseEMs remains lacking. Here, we demonstrate a universal charge-compensating strategy to improve the charge-storage capability of PseEMs intrinsically: i) in the elec-trolyte with anion as charge carriers (such as OH-), reducing the multivalent cations of PseEMs into lower valences could create more reversible low-to-high valence redox couples to promote the intercalation of the anions; ii) in the electrolytes with cation as charge carriers (such as H+,Li+,Na+), oxidizing the mul-tivalent cations of PseEMs into higher valences could introduce more reversible high-to-low valence redox couples to promote the intercalation of the cations. And we demonstrated that the improved intrinsic charge-storage capability for PseEMs originates from the increased Faradaic charge storage sites. 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

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PtCoNi ternary intermetallic compounds anchored on Co, Ni and N co-doped mesoporous carbon: Synergetic effect between PtCoNi nanoparticles and doped mesoporous carbon promotes the catalytic activity Chaozhong Li, Weiyue Zhao, Xueyi Lu, Zhangsen Chen, Bing Han, Xiaorong Zhang, Jiaxiang Chen, Yijia Shao, Junlang Huo, Yuexiang Zhu, Yonghong Deng, Shuhui Sun, Shijun Liao 2023, 78(3): 340-373.  DOI: 10.1016/j.jechem.2022.12.005 Abstract ( 31 )   PDF (2341KB) ( 14 )   Highly active and robust electrocatalysts are desired for proton exchange membrane fuel cells. Pt-based intermetallic compounds (IMCs) have been recognized as one of the most promising low-platinum cat-alysts for fuel cells (FCs). Herein, we report a high-performance IMCs by anchoring ordered PtCoNi tern-ary nanoparticles on the N, Co and Ni co-doped dodecahedral mesoporous carbon (DMC). While the introduced Co and Ni participate in the formation of PtCoNi IMCs, some of them are doped in the meso-porous carbon and coordinated by N to form Co-Ny/Ni-Nz dual active centers, which further enhances the electrocatalytic activity towards oxygen reduction reaction. Moreover, the addition of Ni results in a neg-ative shift of the d-band center of Pt as compared to the Pt/DMC and Pt3Co/DMC, making it easier to adsorb oxygen on the surface. As expected, our optimal sample Pt3Co0.7Ni0.3/DMC exhibits excellent per-formance with mass activity and specific activity of 1.32 A mgPt1 and 1.98 mA cm-2 at 0.9 V, which are 7.33 and 6.19 times that of commercial Pt/C, respectively. The Pt3Co0.7Ni0.3/DMC also reveals much better catho-dic performance in an H2-air single fuel cell than commercial Pt/C catalyst with a power density of 0.802 W cm-2. This work provides critical sights into constructing efficient catalysts by ternary intermetallic strategy and synergetic effect between active components and support.

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Dynamically-evolved surface heterojunction in iridium nanocrystals boosting acidic oxygen evolution and overall water splitting Chenyu Yang, Xiuxiu Zhang, Qizheng An, Meihuan Liu, Wanlin Zhou, Yuanli Li, Fengchun Hu, Qinghua Liu, Hui Su 2023, 78(3): 374-380.  DOI: 10.1016/j.jechem.2022.12.032 Abstract ( 20 )   PDF (1781KB) ( 13 )   Simultaneously realizing improved activity and stability of acidic oxygen evolution reaction (OER) elec-trocatalysts is highly promising for developing cost-effective sustainable energy in the splitting of water technique. Herein, we report iridium nanocrystals embedded into 3D conductive clothes (Ir-NCT/CC) as a low iridium electrocatalyst realizing ultrahigh acidic OER activity and robust stability. The well-designed Ir-NCT/CC requires a low overpotential of 202 mV to reach the current density of 10 mA cm-2 with a high mass activity of 1754 A g-1. Importantly, in acidic overall water splitting, Ir-NCT/CC merely delivers a cell voltage of 1.469 V at a typical current density of 10 mA cm-2 and also maintains robust durability under continuous operation. We identify that a low working voltage drives the formation of a highly stable amorphous IrOx active phase over the surface of Ir nanocrystals (surface heterojunction IrOx/Ir-NCT) dur-ing operating conditions, which contributes to an effective and durable OER process.

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Mechanism of high-concentration electrolyte inhibiting the destructive effect of Mn(II) on the performance of lithium-ion batteries Xiaoling Cui, Jinlong Sun, Dongni Zhao, Jingjing Zhang, Jie Wang, Hong Dong, Peng Wang, Junwei Zhang, Shumin Wua, Linhu Song, Ningshuang Zhang, Chunlei Li, Shiyou Li 2023, 78(3): 381-392.  DOI: 10.1016/j.jechem.2022.12.008 Abstract ( 24 )   PDF (3634KB) ( 19 )   By optimizing electrolyte formulation to inhibit the deposition of transition metal ions (TMIs) on the sur-face of the graphite anode is an effective way to improve the electrochemical performance of lithium-ion batteries. At present, it is generally believed the formation of an effective interfacial film on the surface of the anode electrode is the leading factor in reducing the dissolution of TMIs and prevent TMIs from being embedded in the electrode. It ignores the infiuence of the solvation structures in the electrolyte system with different composition, and is not conducive to the design of the electrolyte formulation from the perspective of changing the concentration and the preferred solvent to inhibit the degradation of battery performance caused by TMIs deposition. In this work, by analyzing the special solvation structures of the high-concentration electrolyte, we study the main reason why high-concentration electrolyte inhibits the destructive effect of Mn (II) on the electrochemical performance of LIBs. By combining the potential-resolved in-situ electrochemical impedance spectroscopy technology (PRIs-EIS) and density functional theory (DFT) calculation, we find that Mn (II) mainly exists in the form of contact ions pairs (CIPs) and aggregates (AGGs) in high-concentration electrolyte. These solvation structures can reduce the destruc-tive effect of Mn (II) on battery performance from two aspects: on the one hand, it can rise the lowest unoccupied orbital (LUMO) value of the solvation structures of Mn (II), thereby reducing the chance of its reduction; on the other hand, the decrease of Mn2+ ions reduction can reduce the deposition of metal-lic manganese in the solid electrolyte interphase (SEI), thereby avoiding the continuous growth of the SEI. This study can be provided inspiration for the design of electrolytes to inhibit the destructive effect of TMIs on LIBs.

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Sb-Cu alloy cathode with a novel lithiation mechanism of ternary intermetallic formation: Enabling high energy density and superior rate capability of liquid metal battery Peng Chu, Jie Wang, Hongliang Xie, Qian Zhang, Jiangyuan Feng, Zehao Li, Zhao Yang, Hailei Zhao 2023, 78(3): 393-400.  DOI: 10.1016/j.jechem.2022.12.012 Abstract ( 13 )   PDF (2399KB) ( 5 )   Antimony (Sb) is an attractive cathode for liquid metal batteries (LMBs) because of its high theoretical voltage and low cost. The main obstacles associated with the Sb-based cathodes are unsatisfactory energy density and poor rate-capability. Herein, we propose a novel Sb64Cu36 cathode that effectively tackles these issues. The Sb64Cu36 (melting point: 525 C) cathode presents a novel lithiation mechanism involv-ing sequentially the generation of Li2CuSb, the formation of Li3Sb, and the conversion reaction of Li2CuSb to Li3Sb and Cu. The generated intermetallic compounds show a unique microstructure of the upper fioated Li2CuSb layer and the below cross-linked structure with interpenetrated Li2CuSb and Li3Sb phases. Compared with Li3Sb, the lower Li migration energy barrier (0.188 eV) of Li2CuSb significantly facilitates the lithium diffusion across the intermediate compounds and accelerates the reaction kinetics. Consequently, the Li||Sb64Cu36 cell delivers a more excellent electrochemical performance (energy den-sity: 353 W h kg-1 at 0.4 A cm-2; rate capability: 0.59 V at 2.0 A cm-2), and a much lower energy storage cost of only 38.45 $ kW h-1 than other previously reported Sb-based LMBs. This work provides a novel cathode design concept for the development of high-performance LMBs in applications for large-scale energy storage.

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Rationally designed hollow carbon nanospheres decorated with S,P co-doped NiSe2 nanoparticles for high-performance potassium-ion and lithium-ion batteries Jiajia Ye, Zizhong Chen, Zhiqiang Zheng, Zhanghua Fu, Guanghao Gong, Guang Xia, Cheng Hu 2023, 78(3): 401-411.  DOI: 10.1016/j.jechem.2022.12.052 Abstract ( 10 )   PDF (3351KB) ( 4 )   Hollow nanostructures with external shells and inner voids have been proved to greatly shorten the transport distance of ions/electrons and buffer volume change, especially for the large-sized potassium-ions in secondary batteries. In this work, hollow carbon (HC) nanospheres embedded with S,P co-doped NiSe2 nanoparticles are fabricated by ‘‘drop and dry” and ‘‘dissolving and precipitation” pro-cesses to form Ni(OH)2 nanocrystals followed by annealing with S and P dopants to form nanoparticles. The resultant S,P-NiSe2/HC composite exhibits excellent cyclic performance with 131.6 mA h g-1 at 1000 mA g-1 after 3000 cycles for K+ storage and a capacity of 417.1 mA h g-1 at 1000 mA g-1 after 1000 cycles for Li+ storage. K-ion full cells are assembled and deliver superior cycling stability with a capacity of 72.5 mA h g-1 at 200 mA g-1 after 500 cycles. The hollow carbon shell with excellent electrical conductivity effectively promotes the transportation and tolerates large volume variation for both K+ and Li+. Density functional theory calculations confirm that the S and P co-doping NiSe2 enables stronger adsorption of K+ ions and higher electrical conductivity that contributes to the improved electrochemical performance.

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Efficient electrooxidation of biomass-derived aldehydes over ultrathin NiV-layered double hydroxides films Biying Liu, Zhikeng Zheng, Yaoyu Liu, Man Zhang, Yuchen Wang, Yangyang Wan, Kai Yan 2023, 78(3): 412-421.  DOI: 10.1016/j.jechem.2022.11.041 Abstract ( 29 )   PDF (3139KB) ( 17 )   Selective upgrading of C=O bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization. Here we declared the efficient electrooxidation of biomass-derived aldehydes family over NiV-layered double hydroxides (LDHs) thin films. Mechanistic studies confirmed the hydro-xyl active intermediate (—OH*) generated on the surface of NiV-LDHs films by employing electrochemical impedance spectroscopy and the electron paramagnetic resonance spectroscopy. By using advanced tech-niques, e.g., extended X-ray absorption fine structure and high-angle annular dark-field scanning trans-mission electron microscopy, NiV-LDHs films with 2.6 nm could expose larger specific surface area. Taking benzaldehyde as a model, high current density of 200 mA cm-2 at 1.8 V vs. RHE, 81.1% conversion, 77.6% yield of benzoic acid and 90.8% Faradaic efficiency were reached, which was superior to most of previous studies. Theoretical DFT analysis was well matched with experimental findings and documented that NiV-LDHs had high adsorption capacity for the aldehydes to suppress the side reaction, and the alde-hydes were oxidized by the electrophilic hydroxyl radicals formed on NiV-LDHs. Our findings offer a uni-versal strategy for the robust upgrading of diverse biomass-derived platform chemicals.

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Bipolar ionomer electrolytes with desirable self-discharge suppression for supercapacitors Wenqiang Wang, Qingyun Zeng, Ruoyu Wang, Gengchao Wang, Chunzhong Li 2023, 78(3): 422-429.  DOI: 10.1016/j.jechem.2022.12.046 Abstract ( 10 )   PDF (1415KB) ( 4 )   Supercapacitors based on electric double layers are prone to serious self-discharge due to electrolyte ion desorption and the resulting energy loss severely limits the application range of supercapacitors. Rational design of polymer electrolyte systems to address this problem shows considerable generality and high feasibility. Herein, we reported a quasi-solid-state bipolar ionomer electrolyte prepared by an in-situ layer-by-layer ultraviolet-curing method, which has an integrated Janus structure with an intermediate binding layer. Based on the synergistic effect of confining impurity ions by ionizable groups and electro-static repulsion to stabilize the electric double layers and superimposing synergies on both sides, the assembled device not only possesses ideal supercapacitor characteristics, but also exhibits an ultra-high voltage retention of 71% after being left to stand for 100 h after being fully charged. Furthermore, through the quasi-in-situ energy dispersive X-ray spectroscopy linear scanning, the characteristics of ion diffusion in this ionomer electrolyte are revealed, suggesting its correlation with self-discharge behavior.

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Enhancing the compatibility of the amyloid-dye hybrid nanostructure for improved photo-biocatalysis Zhen Dong, Yanying Wang, Qin Yang, Dan Li, Peng Wu 2023, 78(3): 430-437.  DOI: 10.1016/j.jechem.2022.12.040 Abstract ( 10 )   PDF (1974KB) ( 4 )   Artificial photosynthesis is significant for renewable energy generation, sustainable development, and environmental protection. Dye-protein hybrids are promising for developing photosynthesis mimics (e.g., photo-biocatalysis), but their performances are far lower than the plant photosystems, partially because of the incompatibility between dye and the protein matrix that limits excited state electron transfer of the included dyes. Here, using ThT-insulin amyloid assembly as a model system, we proposed that increasing the dye-protein compatibility could lead to the improved photo-biocatalytic performance. A ThT derivative, ThTPD, was designed with the same electron acceptor but extended p-conjugated donor structure. When integrated into the insulin amyloid, the extended p-conjugated donor structure allowed increased binding affinity and energy with the amyloid matrix, thus better electron transport to the mediator to drive the photocatalytic reaction. Meanwhile, compared with ThT, ThTPD exhibited improved light absorption and longer excited state lifetime. The photo-biocatalytic performance of ThTPD-insulin amyloid was greatly improved as compared with that of ThT in reduced nicotinamide ade-nine dinucleotide (NADH) regeneration. When integrating with NADH-dependent L-glutamate reductase, the efficiency of the ThTPD-insulin amyloid hybrid was 2.8-fold higher than that of ThT in glutamate gen-eration, showing promising feature in biocatalytic solar-to-chemical conversion.

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Structure-catalytic functionality of size-facet-performance in pentlandite nanoparticles Chenxu Zhang, Chao Jiang, Qi Tang, Zeshuo Meng, Yaxin Li, Yanan Wang, Yanan Cui, Wei Shi, Shansheng Yu, Hongwei Tian, Weitao Zheng 2023, 78(3): 438-446.  DOI: 10.1016/j.jechem.2022.12.023 Abstract ( 6 )   PDF (2786KB) ( 2 )   As one of the pentlandites, Fe5Ni4S8 (FNS) based materials have attracted increasing attention due to their excellent catalytic properties and promising applicability. The control over the catalyst surface structure often benefits its heterogeneous catalytic activity. However, this has not been investigated for FNS mate-rials at the nanoscale regarding the catalytic activity related to high-index facets. Herein, FNS nanopar-ticles (FNSNPs) with enclosed continuous tunable high-index facets were prepared and studied to clarify the relationship between the structure and catalytic functionality. The results suggested strong dependence between exposed facets of FNSNPs and their sizes. The decline in the average size to 5.8 nm led to enclosing by high-index facets (422) and (511) to yield optimal electrocatalytic activities toward the hydrogen evolution reaction. The catalytic activity of FNSNPs was closely related to the sur-face energy of the main exposed facets. These findings clarified the relationship between high-index-facet and high-surface-energy FNSNPs, as promising approaches in crystal surface control engineering.

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In-situ magnetic field enhanced performances in ferromagnetic FeCo2O4nanofibers-based rechargeable Zinc-air batteries Zhengmei Zhang, Lei Jia, Tong Li, Jinmei Qian, Xiaolei Liang, Desheng Xue, Daqiang Gao 2023, 78(3): 447-453.  DOI: 10.1016/j.jechem.2022.12.038 Abstract ( 7 )   PDF (1397KB) ( 2 )   Field-assisted electrocatalytic reactions are demonstrated to be sufficient strategies in enhancing the electrocatalyst activities for oxygen evolution reaction (OER). Here, we report the in-situ magnetic field enhanced electrocatalytic activity in ferromagnetic FeCo2O4 nanofibers. Our results demonstrate that the overpotential of FeCo2O4 nanofibers at 10 mA cm-2 shows a left-shift of 40 mV for the OER by applying an external magnetic field, and no obvious change has been observed in the non-ferromagnetic-order Co3O4 nanofibers. Calculation results indicate that there are more overlaps between the density of states for Co 3d and O 2p by applying an external magnetic field. Accordingly, the spin hybridization of 3d-2p and the kinetics of spin charge transfer are optimized in ferromagnetic FeCo2O4, which can promote the adsorp-tion of oxygen-intermediates and electron transfer, significantly improving its electrocatalytic efficiency. What's more, the maximum power density of the FeCo2O4 nanofibers based Zn-air battery (ZAB) increases from 97.3 mW cm-2 to 108.2 mW cm-2 by applying an external magnetic field, providing a new idea for the application of magnetic cathode electrocatalysts in ZABs.

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Application of an amphipathic molecule at the NiOx/perovskite interface for improving the efficiency and long-term stability of the inverted perovskite solar cells Guibin Shen, Hongye Dong, Fan Yang, Xin Ren Ng, Xin Li, Fen Lin, Cheng Mu 2023, 78(3): 454-462.  DOI: 10.1016/j.jechem.2022.12.015 Abstract ( 17 )   PDF (1905KB) ( 7 )   The presence of defects and detrimental reactions at NiOx/perovskite interface extremely limit the effi-ciency performance and long-term stability of the perovskite solar cells (PSCs) based on NiOx. Herein, an amphipathic molecule Triton X100 (Triton) is modified on the NiOx surface. The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+ on the NiOx surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiOx/perovskite interface. Additionally, the hydrophobic chain of Triton protrudes from the NiOx surface to prevent moisture from penetrating into the NiOx/perovskite interface. Consequently, the NiOx/Triton-based devices (MAPbI3 as absorbing layer) show superior moisture and thermal stability, retaining 88.4% and 64.3% of the initial power con-version efficiency after storage in air (40%-50% relative humidity (RH)) at 25 ℃ for 1070 h and in N2 at 85 ℃ for 800 h, respectively. Moreover, the efficiency increases from 17.59% to 19.89% because of the pas-sivation defect and enhanced hole-extraction capability. Besides, the NiOx/Triton-based PSCs with Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices, indicating the viability of our strategies. Of partic-ular note, a champion PCE of 22.35% and 20.46% was achieved for small-area (0.1 cm2) and large-area (1.2 cm2) NiOx/Triton-based devices, respectively.

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Comparison and integration of CuInGaSe and perovskite solar cells Weiguang Chi, Sanjay K. Banerjee 2023, 78(3): 463-475.  DOI: 10.1016/j.jechem.2022.12.039 Abstract ( 14 )   PDF (8200KB) ( 4 )   The rapidly developing perovskite solar cells (PSCs) provide a new and promising choice of thin film solar cells due to their attractive attributes. Among the commercialized thin film solar cells, CuInGaSe (CIGS) cells demonstrate higher efficiency than amorphous Si photovoltaic devices and lower toxicity than CdTe cells. Therefore, a wide variety of studies have been conducted on them. Here, we elucidate CIGS mate-rials and perovskites as absorber in thin film solar cells in terms of structure and optoelectronic proper-ties. Furthermore, a comparison of PSCs and commercialized CIGS cells is made from the point of view of fabrication process, stability, and toxicity. In addition, the integration of CIGS devices and PSCs is elabo-rated based on tandem architecture. Finally, prospects for the advancement of CIGS cells and PSCs are discussed.

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Moderate heat treatment of CoFe Prussian blue analogues for enhanced oxygen evolution reaction performance Fangyuan Diao, Mikkel Rykær Kraglund, Huili Cao, Xiaomei Yan, Pei Liu, Christian Engelbrekt, Xinxin Xiao 2023, 78(3): 476-486.  DOI: 10.1016/j.jechem.2022.11.050 Abstract ( 15 )   PDF (3162KB) ( 3 )   Prussian blue analogues (PBAs) with inherent ordered structures and abundant metal ion sites are widely explored as precursors for various electrochemical applications, including oxygen evolution reaction (OER). Using a range of characterization techniques including Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and energy dispersive spec-troscopy (EDS), this work discloses the process of replacement of K+ by NH4+ in the interstitial spaces of the CoFe PBA by a hot aqueous urea solution, which infiuences the transformation of PBAs under further heat treatment and the OER performance of the derivatives. After heat treatment at 400 C under Ar fiow, high-resolution transmission electron microscopy (HRTEM) images reveal that CoFe alloy nanoparticles grew on the crystalline cubes of CoFe PBA with K+, while CoFe PBA cubes with NH4+ become amorphous. Besides, the derivative of CoFe PBA with NH4+ (Ar-U-CoFe PBA) performs better than the derivative of CoFe PBA with K+ (Ar-CoFe PBA) in OER, registering a lower overpotential of 305 mV at 10 mA cm-2, a smaller Tafel slope of 36.1 mV dec-1, and better stability over a testing course of 20 h in 1.0 M KOH. A single-cell alkaline electrolyzer, using Ar-U-CoFe PBA and Pt/C for the anodic and cathodic catalyst, respectively, requires an initial cell voltage of 1.66 V to achieve 100 mA cm-2 at 80℃, with negligible degradation after 100 h.

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Ti-Fe2O3/Ni(OH)x as an efficient and durable photoanode for the photoelectrochemical catalysis of PET plastic to formic acid Xin Li, Jianying Wang, Mingze Sun, Xufang Qian, Yixin Zhao 2023, 78(3): 487-496.  DOI: 10.1016/j.jechem.2022.12.031 Abstract ( 3 )   PDF (2320KB) ( 2 )   Photoelectrochemical (PEC) technology provides a promising prospect for the transformation of poly-ethylene terephthalate (PET) plastic wastes to produce value-added chemicals. The PEC catalytic systems with high activity, selectivity and long-term durability are required for the future up-scaling industrial applications. Herein, we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol (EG, derived from PET hydrolysate) oxida-tion to formic acid. The interfacial modification between Fe2O3 semiconductor and Ni(OH)x cocatalyst with ultrathin TiOx interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers, but also kept the high Faradaic efficiency (over 95% in 30 h) towards the value-added formic acid product. This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.

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Overdischarge-induced evolution of Cu dendrites and degradation of mechanical properties in lithium-ion batteries Zixin Guo, Siguo Yang, Wenyang Zhao, Shenghui Wang, Jiong Liu, Zhichao Ma, Hongwei Zhao, Luquan Ren 2023, 78(3): 497-506.  DOI: 10.1016/j.jechem.2022.12.013 Abstract ( 14 )   PDF (2377KB) ( 17 )   The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density, safety, and cycle life of the batteries. However, establishing the correlation between depth of overdischarge and mechanical properties is still a significant challenge. Studying the correlation between depth of overdischarge and mechanical properties is of great significance to improv-ing the energy density and the ability to resist abuse of the batteries. In this paper, the mechanical prop-erties of the battery materials during the whole process of overdischarge from discharge to complete failure were studied. The effects of depth of overdischarge on the elastic modulus and hardness of the cathode of the battery, the tensile strength and the thermal shrinkage rate of the separator, and the per-formance of binder were investigated. The precipitation of Cu dendrites on the separator and cathode after dissolution of anode copper foil is a key factor affecting the performance of battery materials. The Cu dendrites attached to the cathode penetrate the separator, causing irreversible damage to the coating and base film of the separator, which leads to a sharp decline in the tensile strength, thermal shrinkage rate and other properties of the separator. In addition, the Cu dendrites wrapping the cathode active particles reduce the adhesion of the active particles binder. Meanwhile, the active particles are damaged, resulting in a significant decrease in the elastic modulus and hardness of the cathode.

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Towards a business model for second-life batteries: Barriers, opportunities, uncertainties, and technologies Carlos Antônio Rufino Júnior, Eleonora Riva Sanseverino, Pierluigi Gallo, Daniel Koch, Yash Kotak, Hans-Georg Schweiger, Hudson Zanin 2023, 78(3): 507-525.  DOI: 10.1016/j.jechem.2022.12.019 Abstract ( 16 )   PDF (1199KB) ( 6 )   Electric vehicles (EVs) and the recent pandemic outbreak give cities a new trend to primarily private and shared mobility with low noise and less air pollution. Crucial factors for the widespread of EVs are the electrical charging infrastructure, driving range, and the reduction of the cost of battery packets. For this reason, there is a massive effort from manufacturers, governments, and the scientific community to reduce battery costs and boost sustainable electrical production and distribution. Battery reuse is an alternative to reduce batteries' costs and environmental impacts. Second-life batteries can be used in a wide variety of secondary applications. Second-life batteries can be connected with off-grid or on-grid photovoltaic and wind systems, vehicle charging stations, forklifts, and frequency control. The present work aims to analyze the main challenges imposed on the reuse of batteries, the leading technologies for their reuse, and the different types of batteries in terms of their feasibility for second-life use. The main novelty of this work is the discussion about the barriers, opportunities, uncertainties, and technolo-gies for the second life market. Here we summarize the present state of the art in reusing lithium-ion bat-teries discussing technical and economic feasibility, environmental impacts, and perspectives. The results show five business models that have been proposed in the literature, three types of markets for trading second-life batteries, and the main opportunities and barriers for each actor in the battery supply chain. 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

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Synergy in magnetic NixCo1Oy oxides enables base-free selective oxidation of 5-hydroxymethylfurfural on loaded Au nanoparticles Hao Zhang, Yinghao Wang, Qizhao Zhang, Bang Gu, Qinghu Tang, Qiue Cao, Kun Wei, Wenhao Fang 2023, 78(3): 526-536.  DOI: 10.1016/j.jechem.2022.11.057 Abstract ( 14 )   PDF (2616KB) ( 5 )   The base-free aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) in water is recognized as an important and sustainable upgrading process for cellulosic carbohydrates. However, selectivity control still remains a challenge. Here, we disclose that the unique synergy in mag-netic NixCo1Oy (x = 1, 3 and 5) bimetallic oxides can induce reactive oxygen defects and simultaneously stabilize small-sized metallic Au nanoparticles in the Au/NixCo1Oy catalysts. Such catalytic features ren-der effective adsorption and activation of O2, OH and C=O groups, realizing selective oxidation of HMF to FDCA. On a series of magnetic Au/NixCo1Oy catalysts with almost identical Au loadings (ca. 0.5 wt%) and particle sizes (ca. 2.7 nm), the variable Ni/Co molar ratios give rise to the tunable electron density of Au sites and synergistic effect between NiO and CoOy. The initial conversion rates of HMF and its derived intermediates (i.e., DFF, HMFCA and FFCA) show a volcano-like dependence on the number of oxygen defects (i.e., O2- and O-) and electron-rich Au0 sites. The optimum Au/Ni3Co1Oy catalyst exhibits a highest productivity of FDCA (12.5 mmolFDCA mol-1 Au h-1) among all the Au catalysts in the literature and achieves > 99% yield of FDCA at 120 ℃ and 10 bar of O2. In addition, this catalyst can be easily recovered by a magnet and show superior stability and reusability during six consecutive cycling tests. This work may shed a light on Au catalysis for the base-free oxidation of biomass compounds by smartly using the synergy in bimetallic oxide carriers.

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Recent progress of advanced manganese oxide-based materials for acidic oxygen evolution reaction: Fundamentals, performance optimization, and prospects Mengwei Guo, Rongrong Deng, Chaowu Wang, Qibo Zhang 2023, 78(3): 537-553.  DOI: 10.1016/j.jechem.2022.11.054 Abstract ( 25 )   PDF (3457KB) ( 8 )   The oxygen evolution reaction (OER) is the basis of various sustainable energy conversion and storage techniques, especially hydrogen production by water electrolysis. To realize the practical application of hydrogen energy and mass-scale hydrogen production via water electrolysis, several obstacles, such as the multi-electron transfer OER process with sluggish kinetics and overall high reaction barrier, should be overcome. Manganese oxide-based (MnOx) materials, especially MnO2, have emerged as promising non-noble electrocatalysts for water electro-oxidation under acidic conditions due to their well-balanced properties between catalytic activity and stability. This review introduces the fundamental understanding of the catalytic OER process on MnOx-based materials, including the conventional adsor-bate evolution mechanism (AEM) and emerging lattice oxygen oxidation mechanism (LOM). The rational screening and prediction of MnOx-based catalysts that can stably catalyze OER in acid are summarized based on Pourbaix diagram analysis and thermodynamic density functional theory (DFT) calculations. Then, the up-to-date progress of upgrading the OER catalytic performance of MnOx-based catalysts by composite construction is reviewed. Afterward, feasible strategies to improve the electrocatalytic activity and lifetime of MnOx-based catalysts are systemically discussed in terms of crystal structure control, rea-sonable setting of working potential and electrolyte environment, optimal selection of acid-stable con-ductive supports, and self-healing engineering. Finally, future scientific challenges and research directions are outlined to guide the construction of advanced MnOx-based electrocatalysts for OER in acid.

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Highly dispersed 1 nm PtPd bimetallic clusters for formic acid electrooxidation through a CO-free mechanism Zhongying Fang, Ziwei Zhang, Shemsu Ligani Fereja, Jinhan Guo, Xinjie Tong, Yue Zheng, Rupeng Liu, Xiaolong Liang, Leting Zhang, Zongjun Li, Wei Chen 2023, 78(3): 554-564.  DOI: 10.1016/j.jechem.2022.12.018 Abstract ( 12 )   PDF (1774KB) ( 5 )   Direct formic acid fuel cell (DFAFC) is an important research project in clean energy field. However, com-mercialization of DFAFC is still largely limited by the available catalysts with unsatisfied activity, dura-bility and cost for formic acid electrooxidation (FAEO). Using Pt- and Pd-based nanoclusters as electrocatalysts is a particularly promising strategy to solve the above problem, but two attendant prob-lems need to be solved firstly. (I) The controllable synthesis of practicable and stable sub-2 nm clusters remains challenging. (II) The catalyzing mechanism of sub-2 nm metal clusters for FAEO has not yet com-pletely understood. Herein, different from traditional solution synthesis, by designing a novel supporting material containing electron-rich and electron-deficient functional groups, size- and dispersion-controllable synthesis of ~1 nm PtPd nanoclusters is realized by an electrochemical process. The electro-catalytic properties and reaction mechanism of the PtPd nanoclusters for the FAEO were studied by dif-ferent electrochemical techniques, in-situ fourier transform infrared (FTIR) spectra and density functional theory (DFT) calculations. The tiny PtPd nanoclusters have much higher catalytic activity and durability than commercial Pt/C, Pd/C and 3.5 nm PtPd nanoparticles. The present study shows that the metal-reactant interaction plays a decisive role in determining the catalytic activity and cluster-support inter-action plays a decisive role in enhancing the durability of electrocatalyst. The ratio and arrangement of Pt and Pd atoms on the surface of 1 nm PtPd cluster as well as the overall valence state, d-band center and specific surface area make them exhibit different catalytic performance and reaction mechanism from nanoparticle catalysts. In addition, in situ FTIR and DFT calculations showed that on the surface of PtPd clusters, the generation of CO2 through trans-COOH intermediate is the most optimal reaction path-way for the FAEO.

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Deep learning enhanced lithium-ion battery nonlinear fading prognosis Shanling Ji, Jianxiong Zhu, Zhiyang Lyu, Heze You, Yifan Zhou, Liudong Gu, Jinqing Qu, Zhijie Xia, Zhisheng Zhang, Haifeng Dai 2023, 78(3): 565-573.  DOI: 10.1016/j.jechem.2022.12.028 Abstract ( 7 )   PDF (1330KB) ( 4 )   With the assistance of artificial intelligence, advanced health prognosis technique plays a critical role in the lithium-ion (Li-ion) batteries management system. However, conventional data-driven early aging prediction exhibited dramatic drawbacks, i.e., volatile capacity nonlinear fading trajectories create obsta-cles to the accurate multistep ahead prediction due to the complex working conditions of batteries. Herein, a novel deep learning model is proposed to achieve a universal and accurate Li-ion battery aging prognosis. Two battery datasets with various electrode types and cycling conditions are developed to val-idate the proposed approaches. Knee-point probability (KPP), extracted from the capacity loss curve, is first proposed to detect knee points and improve state-of-health (SOH) predictive accuracy, especially during periods of rapid capacity decline. Using one-cycle data of partial raw voltage as the model input, the SOH and KPP can be simultaneously predicted at multistep ahead, whereas the conventional method showed worse accuracy. Furthermore, to explore the underlying characteristics among various degrada-tion tendencies, an online model update strategy is developed by leveraging the adversarial adaptation-induced transfer learning technique. This work gains new sights into the comprehensive Li-ion battery management and prognosis framework through decomposing capacity degradation trajectories and adversarial learning on the unlabeled samples.

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LiTFSI salt concentration effect to digest lithium polysulfides for high-loading sulfur electrodes Jin-Kwang Song, Moonsoo Kim, Seongbae Park, Young-Jun Kim 2023, 78(3): 574-581.  DOI: 10.1016/j.jechem.2022.11.038 Abstract ( 11 )   PDF (2054KB) ( 5 )   Sulfur utilization improvement and control of dissolved lithium polysulfide (LiPS; Li2Sx,2 < x ≤ 8) are cru-cial aspects of the development of lithium-sulfur (Li-S) batteries, especially in high-loading sulfur elec-trodes and low electrolyte/sulfur (E/S) ratios. The sluggish reaction in the low E/S ratio induces poor LiPS solubility and unstable Li2S electrodeposition, resulting in limited sulfur utilization, especially under high-loading sulfur electrode. In this study, we report on salt concentration effects that improve sulfur utilization with a high-loading cathode (6 mgsulfur cm-2), a high sulfur content (80 wt%) and a low E/S ratio (5 mL g-1sulfur). On the basis of the rapid LiPS dissolving in a low concentration electrolyte, we estab-lished that the quantity of Li2S electrodeposition from a high Li+ diffusion coefficient, referring to the reduction of LiPS precipitation, was significantly enhanced by a faster kinetic. These results demonstrate the importance of kinetic factors for the rate capability and cycle life stability of Li-S battery electrolytes through high Li2S deposition under high-loading sulfur electrode.

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Prediction of impedance responses of protonic ceramic cells using artificial neural network tuned with the distribution of relaxation times Xuhao Liu, Zilin Yan, Junwei Wub, Jake Huang, Yifeng Zheng, Neal P. Sullivan, Ryan O'Hayre, Zheng Zhong, Zehua Pan 2023, 78(3): 582-588.  DOI: 10.1016/j.jechem.2022.12.055 Abstract ( 6 )   PDF (1731KB) ( 4 )   A deep-learning-based framework is proposed to predict the impedance response and underlying electro-chemical behavior of the reversible protonic ceramic cell (PCC) across a wide variety of different operat-ing conditions. Electrochemical impedance spectra (EIS) of PCCs were first acquired under a variety of operating conditions to provide a dataset containing 36 sets of EIS spectra for the model. An artificial neu-ral network (ANN) was then trained to model the relationship between the cell operating condition and EIS response. Finally, ANN model-predicted EIS spectra were analyzed by the distribution of relaxation times (DRT) and compared to DRT spectra obtained from the experimental EIS data, enabling an assess-ment of the accumulative errors from the predicted EIS data vs the predicted DRT. We show that in cer-tain cases, although the R2 of the predicted EIS curve may be > 0.98, the R2 of the predicted DRT may be as low as 0.3. This can lead to an inaccurate ANN prediction of the underlying time-resolved electrochem-ical response, although the apparent accuracy as evaluated from the EIS prediction may seem acceptable. After adjustment of the parameters of the ANN framework, the average R2 of the DRTs derived from the predicted EIS can be improved to 0.9667. Thus, we demonstrate that a properly tuned ANN model can be used as an effective tool to predict not only the EIS, but also the DRT of complex electrochemical systems.

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Regulating solid electrolyte interphases on phosphorus/carbon anodes via localized high-concentration electrolytes for potassium-ion batteries Wei Xiao, Peiyi Shi, Zhengkui Li, Chong Xie, Jian Qin, Huijuan Yang, Jingjing Wang, Wenbin Li, Jiujun Zhang, Xifei Li 2023, 78(3): 589-605.  DOI: 10.1016/j.jechem.2022.12.041 Abstract ( 13 )   PDF (4063KB) ( 8 )   The resourceful and inexpensive red phosphorus has emerged as a promising anode material of potassium-ion batteries (PIBs) for its large theoretical capacities and low redox potentials in the multi-electron alloying/dealloying reactions, yet chronically suffering from the huge volume expansion/shrink-age with a sluggish reaction kinetics and an unsatisfactory interfacial stability against volatile elec-trolytes. Herein, we systematically developed a series of localized high-concentration electrolytes (LHCE) through diluting high-concentration ether electrolytes with a non-solvating fiuorinated ether to regulate the formation/evolution of solid electrolyte interphases (SEI) on phosphorus/carbon (P/C) anodes for PIBs. Benefitting from the improved mechanical strength and structural stability of a robust/uniform SEI thin layer derived from a composition-optimized LHCE featured with a unique solvation structure and a superior K+ migration capability, the P/C anode with noticeable pseudocapacitive behaviors could achieve a large reversible capacity of 760 mA h g-1 at 100 mA g-1, a remarkable capacity retention rate of 92.6% over 200 cycles at 800 mA g-1, and an exceptional rate capability of 334 mA h g-1 at 8000 mA g-1. Critically, a suppressed reduction of ether solvents with a preferential decomposition of potassium salts in anion-derived interfacial reactions on P/C anode for LHCE could enable a rational con-struction of an outer organic-rich and inner inorganic-dominant SEI thin film with remarkable mechan-ical strength/fiexibility to buffer huge volume variations and abundant K+ diffusion channels to accelerate reaction kinetics. Additionally, the highly reversible/durable full PIBs coupling P/C anodes with annealed organic cathodes further verified an excellent practical applicability of LHCE. This encouraging work on electrolytes regulating SEI formation/evolution would advance the development of P/C anodes for high-performance PIBs.