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2023, Vol. 83, No. 8　Online: 15 August 2023

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Universal machine learning potential accelerates atomistic modeling of materials Zhongheng Fu, Dawei Zhang 2023, 83(8): 1-2.  DOI: 10.1016/j.jechem.2023.04.009 Abstract ( 10 )   PDF (1459KB) ( 21 )

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Mitigating thermal runaway hazard of high-energy lithium-ion batteries by poison agent Xin Lai, Zheng Meng, Fangnan Zhang, Yong Peng, Weifeng Zhang, Lei Sun, Li Wang, Fei Gao, Jie Sheng, Shufa Su, Yuejiu Zheng, Xuning Feng 2023, 83(8): 3-15.  DOI: 10.1016/j.jechem.2023.03.050 Abstract ( 17 )   PDF (13840KB) ( 15 )   Lithium-ion batteries with high-energy density are extensively commercialized in long-range electric vehicles. However, they are poor in thermal stability and pose fire or explosion, which has attracted the global attention. This study describes a new route to mitigate the battery thermal runaway (TR) hazard by poison agents. First, the self-destructive cell is built using the embedded poison layer. Then, the poisoning mechanism and paths are experimentally investigated at the material, electrode, and cell levels. Finally, the proposed route is verified by TR tests. The results show the TR hazard can be significantly reduced in the self-destructive cell based on a new reaction sequence regulation. Specifically, the maximum temperature of the self-destructive cell is more than 300 °C lower than that of the normal cell during TR. The drop in maximum temperature can reduce total heat release and the probability of TR propagation in the battery system, significantly improving battery safety.

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Dual-salt assisted synergistic synthesis of Prussian white cathode towards high-capacity and long cycle potassium ion battery Rui Ma, Zixing Wang, Qingfeng Fu, Wang Zhou, Ying Mo, Jian Tu, Zhiyong Wang, Peng Gao, Changling Fan, Jilei Liu 2023, 83(8): 16-23.  DOI: 10.1016/j.jechem.2023.04.007 Abstract ( 9 )   PDF (9334KB) ( 6 )   Prussian blue analogues (PBAs) are considered as superior cathode materials for potassium-ion batteries (PIBs) because of their three-dimensional open framework structure, high stability, and low cost. However, the intrinsic lattice defects and low potassium content typically results in poor rate and cycling performance, thus limited their practical applications. In this work, high-quality K1.64FeFe(CN)6 (PW-HQ) material with less crystalline water (6.21%) and high potassium content (1.64 mol-1) was successfully synthesized by a novel coprecipitation method with potassium citrate (K-CA) and potassium chloride (KCl) addition. Specifically, the electrode delivers a reversible capacity of 113.1 mA h g-1 at the current rate of 50 mA g-1 with ∼100% coulombic efficiency. Besides, the electrode retained 90% reversible capacity at 500 mA g-1 current density after 1000 cycles, indicating only 0.01% capacity decay per cycle. Moreover, we have revealed that the introduction of K-CA controlled the chelating rate of Fe(II) and the addition of KCl increased the K+ content, hence improving the capacity and stability of the as-prepared electrodes. Structural evolution and potassium storage mechanism were further investigated by detailed ex-situ X-ray diffraction and in-situ Raman measurements, which demonstrated reversible potassiation/depotassiation behavior and negligible volume change during the electrochemical process. In general, this work provides an efficient strategy to eliminate water contents in Prussian blue cathode and improve its electrochemical performance, which plays a key role in promoting the industrialization of potassium ion batteries.

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Spiro-based triphenylamine molecule with steric structure as a cathode material for high-stable all organic lithium dual-ion batteries Liya Huang, Zehao Yu, Liubin Wang, Bin Qin, Fengshi Cai, Zhihao Yuan, Zhiqiang Luo 2023, 83(8): 24-31.  DOI: 10.1016/j.jechem.2023.04.018 Abstract ( 10 )   PDF (5850KB) ( 9 )   Redox p-type organic compounds are promising cathode materials for dual-ion batteries. However, the triphenylamine-based polymers usually with agglomerate and intertwined molecular chain nature limit the maximum reaction of their active sites with large-sized anions. Herein, we demonstrate the application of a small molecule with rigid spirofluorene structure, namely 2,2′,7,7′-tetrakis(diphenylamine)-9,9′-spirobifluorene (Spiro-TAD), as a cathode material for lithium dual-ion batteries. The inherent sterical structure endows the Spiro-TAD with good chemical stability and large internal space for fast diffusion kinetics of anions in the organic electrolyte. As a result, the Spiro-TAD electrode shows significant insolubility and less steric hindrance, and gives a high actual capacity of 109 mA h g-1 (active groups utilization ratio approximately 100%) at 50 mA g-1 with a high discharge voltage of 3.6 V (vs. Li+/Li), excellent rate capability (60 mA h g-1 at 2000 mA g-1) and extremely stable cycling life (98.4% capacity retention after 1400 cycles at 500 mA g-1) in half cells. Such good electrochemical performance is attributed to the robust and rapid adsorption/desorption of ClO4- anions, which can be proved by the in-situ FTIR and XPS. Moreover, an all-organic lithium dual-ion battery (a-OLDIBs) is constructed using the Spiro-TAD as cathode and 3,4,9,10-Perylenetetracarboxylic diimide (PTCDI) as anode and displays long-term cycling performance of 87.5 mA h g-1 after 800 cycles. This study will stimulate further developments in designing all organic battery systems.

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Elaborately tuning the electronic structure of single-atom nickel sites using nickel nanoparticles to markedly enhance the electrochemical reduction of nitrate into ammonia Zichao Xi, Jiaqian Wang, Baocang Liu, Xuan Xu, Peng Jing, Rui Gao, Jun Zhang 2023, 83(8): 32-42.  DOI: 10.1016/j.jechem.2023.03.037 Abstract ( 8 )   PDF (15694KB) ( 2 )   The electrochemical reduction of nitrate to ammonia (NH3) can be used to recycle nitrogen and offers a decarbonized route for sustainable NH3 production, but requires efficient electrocatalysts. Herein, we have rationally designed and fabricated a novel self-supported electrocatalyst comprised of Ni nanoparticles (NiNPs) embedded in Ni single atoms (NiSAs) anchored to nitrogen-doped carbon nanotubes grown on carbon cloth (NiNPs@NiSAs-NCNTs/CC) used for an efficient nitrate reduction reaction (NO3-RR) to produce NH3. The electrocatalyst can attain a maximum NH3 yield rate of 27.67 ± 1.16 mgNH3 h-1 cm-2 at -1.4 V vs. reversible hydrogen electrode (RHE) and nearly 100% Faradic efficiency in the range of -1.2 - -1.4 V vs. RHE in a neutral medium, outperforming the previously reported Ni-based catalysts. Our experimental analysis and theoretical calculations have demonstrated that the moderate electron-deficient state of NiSAs regulated by NiNPs not only facilitates the enrichment of NO3-, but also benefits the formation of NO3* and decrease in the energy barrier of the rate-limiting step, thus resulting in the enhanced NO3-RR performance.

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Integrated host configuration of flexibly fibrous skeleton towards efficient polysulfide conversion and dendrite-free behavior in stable lithium-sulfur pouch cells Tongtao Wan, Yusen He, Zongke He, Wenjia Han, Yongguang Zhang, Guihua Liu 2023, 83(8): 43-52.  DOI: 10.1016/j.jechem.2023.03.053 Abstract ( 4 )   PDF (12910KB) ( 6 )   The commercialization of lithium-sulfur (Li-S) batteries is obstructed by the sluggish sulfur electrochemical reaction, severe polysulfide shuttling effect, and damaging dendritic lithium growth. Herein, a three-dimensional (3D) conductive carbon nanofibers skeleton-based bifunctional electrode host material is fabricated, which consists of a two-dimensional (2D) ultra-thin NiSe2-CoSe2 heterostructured nanosheet built on one-dimensional (1D) carbon nanofibers (NiSe2-CoSe2@CNF). When serving as cathodic host, the heterostructured NiSe2-CoSe2@CNF offers a synergistic function of polysulfide confinement and catalysis conversion. The S/NiSe2-CoSe2@CNF cathode shows outstanding cycling stability of 0.03% capacity decay rate per cycle over 500 cycles at 1 C. As anodic host, the NiSe2-CoSe2@CNF with high-flux Li+ diffusion property and good lithiophilic capability realizes dendrite-free Li plating/stripping behavior. Benefiting from these synergistically merits, the Li-S full cell with S/NiSe2-CoSe2@CNF|Li/NiSe2-CoSe2@CNF electrodes exhibits excellent electrochemical performance including a high specific capacity of 1021 mA h g-1 over 100 cycles at 0.2 C and reversible areal capacity of 3.05 mA h cm-2 under a high sulfur loading of 4.33 mg cm-2 at 0.1 C. The pouch cell also delivers ultra-stable Li/S electrochemistry. This study demonstrates a rational and universal electrode construction strategy for developing practical and high-energy Li-S batteries.

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Unlocking high-rate O3 layered oxide cathode for Na-ion batteries via ion migration path modulation Guoliang Liu, Weile Xu, Jianghua Wu, Yong Li, Liping Chen, Shuyue Li, Qinghui Ren, Juan Wang 2023, 83(8): 53-61.  DOI: 10.1016/j.jechem.2023.04.029 Abstract ( 58 )   PDF (11529KB) ( 49 )   O3-NaNi1/3Fe1/3Mn1/3O2 is a promising layered cathode material with high specific capacity, low cost, and simple synthesis. However, sluggish kinetic hindrance is attributed to the size discrepancy between the large Na-ion and narrow tetrahedral interstitial positions, leading to inferior rate capacity and low reversible capacity. Herein, F- with light‐weight and strong electronegativity is introduced to substitute O atoms in the bulk structure, which intensifies the bond strength of transition metal and oxygen and enlarges the Na+ diffusion channel. In addition, density-functional theory (DFT) calculations demonstrate that the electrostatic interaction is weakened between Na+ in the tetrahedral site and the transition-metal cation directly below it, dramatically reducing the migration barriers of Na+ diffusion. Consequently, the as-obtained NaNi1/3Fe1/3Mn1/3O1.95F0.05 sample displays outstanding rate performance of 86.7 mA h g-1 at 10 C and excellent capacity retention of 84.1% after 100 cycles at 2 C. Moreover, a full cell configuration using a hard carbon anode reaches the energy density of 307.7 Wh kg-1. This strategy paves the way for novel means of modulating the Na-ion migration path for high-rate O3-type layered cathode materials.

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Advances in photothermal conversion of carbon dioxide to solar fuels Wa Gao, Yinwen Li, Dequan Xiao, Ding Ma 2023, 83(8): 62-78.  DOI: 10.1016/j.jechem.2023.04.024 Abstract ( 14 )   PDF (12158KB) ( 10 )   Converting carbon dioxide (CO2) into useful fuels or chemical feedstocks is important for achieving peak carbon emission and carbon neutrality. Recently, photothermal catalysis has been extensively studied and applied due to its advantages over traditional heat-driven catalysis. In this review, we focus on photothermal catalysis of thermodynamically uphill reactions that convert CO2 into value-added products. We first introduce the fundamentals of photothermal catalysis for CO2 reduction, including the definition and classification of photothermal catalysis, followed by their photothermal conversion processes. The structure design of different types of photothermal catalysts is summarized. The superior performance of photothermal catalytic conversion of CO2 is illustrated and discussed, including improved CO2 activation, tunable selectivity towards different solar fuel products, and resistance to sintering and coking. Finally, the perspectives and challenges in this cutting-edge field are presented with the aim of advancing understanding of the underlying mechanisms and inspiring rational design of photothermal catalysts for highly efficient solar-to-fuel conversion.

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Transition metal embedded in nonmetal-doped T-carbon [110]: A superior synergistic trifunctional electrocatalyst for HER, OER and ORR Zhengqin Zhao, Jinbo Hao, Baonan Jia, Xinhui Zhang, Ge Wu, Chunling Zhang, Long Li, Shuli Gao, Yirong Ma, Yuanzi Li, Pengfei Lu 2023, 83(8): 79-89.  DOI: 10.1016/j.jechem.2023.04.003 Abstract ( 8 )   PDF (9659KB) ( 3 )   The design of efficient and low-cost multifunctional electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is critical for the development of clean energy. Two-dimensional (2D) carbon-based nano-materials are becoming more and more popular in heterogeneous catalysis due to their cost-effective and multi-scale tunability as single-atom catalysis (SACs) substrates. In this paper, by using first-principles calculation, we designed and demonstrated a novel macropore T-carbon [110] (TC) monolayer as 2D electrocatalyst substrate for HER/OER/ORR, and the synergistic modification of the transition metal and nonmetal atoms (TM-X) were investigated to enhance the multifunctional electrocatalytic performance. We screened out the Co embedded in N-doped TC (Co3@N-TC) from 30 TM@X-TC monolayers as a trifunctional electrocatalysts, which exhibits superior performance for HER/ORR/OER on both thermodynamic and kinetic scales, and with excellent thermal and electrochemical stability. Then, the TC monolayer is naturally macropore with a diameter of 5.36 Å and exhibits excellent adsorption capacity for the intermediates and products of the redox reactions. Moreover, we revealed the origin of the electrocatalytic activity using the crystal orbital Hamilton population (COHP) and the molecular orbitals (MOs). The d orbital of Co3@N-TC is significantly hybridized with the p orbital of the intermediates, so that the lone electrons initially occupied in the antibonding state pair up and occupy the downward bonding state, allowing *OH to be appropriately adsorbed onto the TC monolayer. This work not only demonstrates that the TM@X-TC monolayer is a superior synergistic trifunctional electrocatalyst, but also reveals a macropore monolayer material with potential applications in electrocatalysis.

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Cu-Zn-based alloy/oxide interfaces for enhanced electroreduction of CO2 to C2+ products Zi-Yang Zhang, Hao Tian, Lei Bian, Shi-Ze Liu, Yuan Liu, Zhong-Li Wang 2023, 83(8): 90-97.  DOI: 10.1016/j.jechem.2023.04.034 Abstract ( 19 )   PDF (10423KB) ( 12 )   The electrochemical CO2 reduction reaction to produce multi-carbon (C2+) hydrocarbons or oxygenate compounds is a promising route to obtain a renewable fuel of high energy density. However, producing C2+ at high current densities is still a challenge. Herein, we develop a Cu-Zn alloy/Cu-Zn aluminate oxide composite electrocatalytic system for enhanced conversion of CO2 to C2+ products. The Cu-Zn-Al-Layered Double Hydroxide (LDH) is used as a precursor to decompose into uniform Cu-Zn oxide/Cu-Zn aluminate pre-catalyst. Under electrochemical reduction, Cu-Zn oxide generates Cu-Zn alloy while Cu-Zn aluminate oxide remains unchanged. The alloy and oxide are closely stacked and arranged alternately, and the aluminate oxide induces the strong electron interaction of Cu, Zn and Al, creating a large number of highly active reaction interfaces composed of 0 to +3 valence metal sites. With the help of the interface effect, the optimized Cu9Zn1/Cu0.8Zn0.2Al2O4 catalyst achieves a Faradaic efficiency of 88.5% for C2+ products at a current density of 400 mA cm-2 at -1.15 V versus reversible hydrogen electrode. The in-situ Raman and attenuate total reflectance-infrared absorption spectroscopy (ATR-IRAS) spectra show that the aluminate oxide at the interface significantly enhances the adsorption and activation of CO2 and the dissociation of H2O and strengthens the adsorption of CO intermediates, and the alloy promotes the C-C coupling to produce C2+ products. This work provides an efficient strategy to construct highly active reaction interfaces for industrial-scale electrochemical CO2RR.

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Uncovering the degradation mechanism induced by ion-diffusion kinetics in large-format lithium-ion pouch cells Shi Zhou, Xiaohong Zhang, Cong Chen, Ming Chen, Fanpeng Kong, Yingjie Qiao, Jiajun Wang 2023, 83(8): 98-105.  DOI: 10.1016/j.jechem.2023.03.051 Abstract ( 6 )   PDF (11172KB) ( 1 )   Battery electrochemistry in an actual cell is a complicated behavior influenced by the current density, uniformity, and ion-diffusion distance, etc. The anisotropism of the lithiation/delithiation degree is usually inevitable, and even worse, due to a trend of big-size cell design, typically such as 4680 and blade cells, which accelerated a battery failure during repeat lithiation and delithiation of cathodes. Inspire by that, two big-size pouch cells with big sizes, herein, are selected to reveal the ion-diffusion dependency of the cathodes at different locations. Interestingly, we find that the LiCoO2 pouch cell exhibits ∼5 A h loss after 120 charge-discharge cycles, but a 15 A h loss is verified in a LiNixMnyCo1-x-yO2 (NCM) cell. Synchrotron-based imaging analysis indicates that higher ion-diffusion rates in the LiCoO2 than that in the LiNixMnyCo1-x-yO2 is the determined factor for the anisotropic cathode fading, which is responsible for a severe mechanical issue of particle damage, such as cracks and even pulverization, in the cathode materials. Meanwhile, we verify the different locations at the near-tab and bottom of the electrode make it worse due to the ion-diffusion kinetics and temperature, inducing a spatially uneven electrochemistry in the big-size pouch cell. The findings give an in-depth insight into pouch cell failure and make a guideline for high-energy cell design and development.

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Long cycle performance of NC@VN/MnO cathode for AZIBs based on Mn/V relay type collaboration Tingting Li, Ruisong Guo, Yang Li, Leichao Meng, Xiaohong Sun, Fuyun Li, Xinqi Zhao, Zhongkai Xu, Jianhong Peng, Lingyun An 2023, 83(8): 106-118.  DOI: 10.1016/j.jechem.2023.03.058 Abstract ( 14 )   PDF (17145KB) ( 4 )   Aqueous zinc ion batteries (AZIBs) have received great attention because of their non-toxicity, high safety, low cost, high abundance, and high specific power. However, their specific capacity is still low compared with lithium ion battery, and current academic research interesting has been focused on developing new cathode materials with high specific capacity. In this study, a Mn/V hybrid polymer framework is designed by a simple self-polymerization scheme. During subsequent calcination, ultrafine VN quantum dots and MnO nanoparticles are generated in situ and stably encapsulated inside N-doped carbon (NC) shells to obtain a novel hybrid cathode NC@VN/MnO for AZIBs. According to the density functional theory (DFT) calculation, the hybrids of MnO and VN can generate both interfacial effects and built-in electric fields that significantly accelerate ion and electron transport by tuning the intrinsic electronic structure, thus enhancing electrochemical performance. A synergistic strategy of composition and structural design allows the rechargeable AZIBs to achieve low-cost and excellent long-cycle performance based on a relay type collaboration at different cycling stages. Consequently, the NC@VN/MnO cathode has output a capacity of 108.3 mA h g-1 after 12,000 cycles at 10 A g-1. These results clearly and fully demonstrate the advantages of the hybrid cathode NC@VN/MnO.

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Enhancing water-dissociation kinetics and optimizing intermediates adsorption free energy of cobalt phosphide via high-valence Zr incorporating for alkaline water electrolysis Huafeng Fan, Dongxu Jiao, Jinchang Fan, Dewen Wang, Bilal Zaman, Wei Zhang, Lei Zhang, Weitao Zheng, Xiaoqiang Cui 2023, 83(8): 119-127.  DOI: 10.1016/j.jechem.2023.04.014 Abstract ( 22 )   PDF (11758KB) ( 10 )   Developing high-efficiency electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free energy of reaction intermediates. Herein, we tackle this challenge by incorporating high-valence Zr into CoP (ZrxCo1-xP), which significantly accelerates the elementary steps of water electrolysis. Theoretical calculations indicate that the appropriate Zr incorporation effectively expedites the sluggish H2O dissociation kinetics and optimizes the adsorption energy of reaction intermediates for boosting the alkaline water electrolysis. These are confirmed by the experimental results of Zr0.06Co0.94P catalyst that delivers exceptional electrochemical activity. The overpotentials at the current density of 10 mA cm-2 (j10) are only 62 (HER) and 240 mV (OER) in alkaline media. Furthermore, the Zr0.06Co0.94P/CC||Zr0.06Co0.94P/CC system exhibits superior overall water splitting activity (1.53 V/j10), surpassing most of the reported bifunctional catalysts. This high-valence Zr incorporation and material design methods explore new avenues for realizing high-performance non-noble metal electrocatalysts.

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Machine learning enables intelligent screening of interface materials towards minimizing voltage losses for p-i-n type perovskite solar cells Wu Liu, Ning Meng, Xiaomin Huo, Yao Lu, Yu Zhang, Xiaofeng Huang, Zhenqun Liang, Suling Zhao, Bo Qiao, Zhiqin Liang, Zheng Xu, Dandan Song 2023, 83(8): 128-137.  DOI: 10.1016/j.jechem.2023.04.015 Abstract ( 17 )   PDF (10401KB) ( 8 )   Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell (PSC) to its limit, and numerous works have been conducted to screen efficient materials. Here, on the basis of the previous studies, we employ machine learning to map the relationship between the interface material and the device performance, leading to intelligently screening interface materials towards minimizing voltage losses in p-i-n type PSCs. To enhance the explainability of the machine learning models, molecular descriptors are used to represent the materials. Furthermore, experimental analysis with different characterization methods and device simulation based on the drift-diffusion physical model are conducted to get physical insights and validate the machine learning models. Accordingly, 3-thiophene ethylamine hydrochloride (ThEACl) is screened as an example, which enables remarkable improvements in VOC and PCE of the PSCs. Our work reveals the critical role of data-driven analysis in the high throughput screening of interface materials, which will significantly accelerate the exploration of new materials for high-efficiency PSCs.

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Bimetallic ZIFs-derived electrospun carbon nanofiber membrane as bifunctional oxygen electrocatalyst for rechargeable zinc-air battery Yanan Ma, Shaoru Tang, Haimeng Wang, Yuxuan Liang, Dingyu Zhang, Xiaoyang Xu, Qian Wang, Wei Li 2023, 83(8): 138-149.  DOI: 10.1016/j.jechem.2023.03.054 Abstract ( 12 )   PDF (11921KB) ( 4 )   The recharged zinc-air battery (ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices. Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB. In this study, the bimetallic ZIFs-containing electrospun (ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process, which was expected to be a bifunctional electrocatalyst for ZABs. Owing to the formed dual single-atomic sites of Co-N4 and Zn-N4, the obtained ES-Co/Zn-CNZIF exhibited the preferable performance toward oxygen reduction reaction (ORR) with E1/2 of 0.857 V and JL of 5.52 mA cm-2, which were more than Pt/C. Meanwhile, it exhibited a marked oxygen evolution reaction (OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles. Furthermore, the ZAB based on the ES-Co/Zn-CNZIF carbon nanofibers membranes delivered peak power density of 215 mW cm-2, specific capacity of 802.6 mA h g-1, and exceptional cycling stability, far larger than Pt/C+RuO2-based ZABs. A solid-state ZAB based on ES-Co/Zn-CNZIF showed better flexibility and stability with different bending angles.

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Construction of Ru/WO3 with hetero-interface structure for efficient hydrogen evolution reaction Xin Xie, Yunxiao Fan, Wanyu Tian, Meng Zhang, Jialin Cai, Xingang Zhang, Jie Ding, Yushan Liu, Siyu Lu 2023, 83(8): 150-157.  DOI: 10.1016/j.jechem.2023.04.026 Abstract ( 13 )   PDF (11277KB) ( 4 )   Water electrolysis is considered as one most promising technique for hydrogen production. The high efficiency electrocatalyst is the key to accelerating the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline media. In this work, an efficient HER electrocatalyst with hetero-interfacial metal-metal oxide structure was constructed through a redox solid phase reaction (SPR) strategy. During the annealing process under Ar atmosphere, RuO2 and WS2 in RuO2/WS2 precursor were converted to Ru nanoparticles (NPs) and WO3 in situ, where tiny Ru NPs and oxygen vacancies were uniformly distributed onto the newly formed WO3 nanosheets. Different characterization techniques were adopted to confirm the successful formation of Ru/WO3 electrocatalyst (RWOC). The optimized RWOC sample annealed at 400 °C exhibited the low overpotential value of 13 mV at a current density of 10 mA cm-2 and strong durability under the alkaline condition. Density functional theoretical calculations further revealed that the promoted adsorption/desorption rate of reaction intermediates and the accelerated kinetics of HER process were deduced to the synergistic effect between Ru and WO3 in electrocatalyst. This work provides a feasible method to fabricate highly efficient HER electrocatalysts.

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Recent progress on efficient perovskite/organic tandem solar cells Rongbo Wang, Meidouxue Han, Ya Wang, Juntao Zhao, Jiawei Zhang, Yi Ding, Ying Zhao, Xiaodan Zhang, Guofu Hou 2023, 83(8): 158-172.  DOI: 10.1016/j.jechem.2023.04.036 Abstract ( 23 )   PDF (13202KB) ( 15 )   The concept of tandem solar cells (TSCs) is an effective way to substantially further improve the efficiency of solar cells. The excellent optoelectronic properties and bandgap tunability of perovskites make them promising for constructing efficient TSCs. Currently, TSCs based on perovskite have been extensively studied. Besides, the performance of organic solar cells has been greatly improved recently due to the wider and more efficient spectral utilization. Accordingly, research on perovskite/organic TSCs has garnered significant attention. It has potential application advantages in emerging fields such as wearable devices by virtue of flexibility. In addition, orthogonal solvents can be adopted to realize the separate preparation of subcells with the solution method, which greatly reduces fabrication complexity; moreover, fabrication with less equipment significantly cuts down the device cost. Meanwhile, organics with more adjustability on the optoelectronic properties provide more tuning strategies for high-performance perovskite/organic TSCs. However, comprehensive and timely reviews on the perovskite/organic TSCs are deficient. Therefore, we expect to accomplish a review on this innovative TSCs to facilitate researchers with a deeper understanding of perovskite/organic TSCs. Herein, we firstly review the significant progress of perovskite and organic solar cells. Then, current achievements of perovskite/organic TSCs are summarized and introduced with a particular focus on the device structure design. Finally, we discuss existential challenges and propose effective strategies for future engineering.

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Tensile stress enhanced dynamic oxygen vacancies on interlayer stretched Bi2O2CO3 as pivotal knobs to promote sustainable selective CO2 photoreduction Xian Shi, Weidong Dai, Xing'an Dong, Qin Ren, Ping Yan, Fan Dong 2023, 83(8): 173-179.  DOI: 10.1016/j.jechem.2023.04.022 Abstract ( 7 )   PDF (6835KB) ( 5 )   Surface oxygen vacancies (OVs) with abundant localized electrons on bismuth-oxygen based photocatalysts are proved to have the ability to capture and activate CO2. However, the surface OVs are easily filled with oxygen-containing species and destroyed, losing their effects as active sites and hindering the subsequent CO2 photoreduction. For realistic and sustainable CO2 photoreduction, constructing sustainable and stable surface OVs as active sites on photocatalysts is essential. This work shows the synthesis of interlayer stretched Bi2O2CO3 ultrathin nanosheets with tensile stress, which are beneficial to continuously generating light-induced dynamic OVs. With sufficient active sites, excellent, stable, and selective photoreduction of CO2 to CO under simulated solar light is achieved. The light-induced OVs can reduce the energy barrier of rate-determining step, resulting in the 100% product selectivity. The results presented herein demonstrate the effect of dynamic OVs induced by interlayer tensile strain on catalysts for the enhanced selective CO2 photoreduction process.

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Metal oxides heterojunction derived Bi-In hybrid electrocatalyst for robust electroreduction of CO2 to formate Runze Ye, Jiaye Zhu, Yun Tong, Dongmei Feng, Pengzuo Chen 2023, 83(8): 180-188.  DOI: 10.1016/j.jechem.2023.04.011 Abstract ( 13 )   PDF (4610KB) ( 4 )   Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO2 reduction reaction (CO2RR). Realizing high selectivity at high current density is important for formate production, but remains challenging. Herein, the BiIn hybrid electrocatalyst, deriving from the Bi2O3/In2O3 heterojunction (MOD-BiIn), shows excellent catalytic performance for CO2RR. The Faradaic efficiency of formate (FEHCOO-) can be realized over 90% at a wide potential window from -0.4 to -1.4 V vs. RHE, while the partial current density of formate (jHCOO-) reaches about 136.7 mA cm-2 at -1.4 V in flow cell without IR-compensation. In addition, the MOD-BiIn exhibits superior stability with high selectivity of formate at 100 mA cm-2. Systematic characterizations prove the optimized catalytic sites and interface charge transfer of MOD-BiIn, while theoretical calculation confirms that the hybrid structure with dual Bi/In metal sites contribute to the optimal free energy of *H and *OCHO intermediates on MOD-BiIn surface, thus accelerating the formation and desorption step of *HCOOH to final formate production. Our work provides a facile and useful strategy to develop highly-active and stable electrocatalysts for CO2RR.

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Beyond two-dimension: One- and zero-dimensional halide perovskites as new-generation passivators for high-performance perovskite solar cells Yuanyuan Zhao, Huimin Xiang, Ran Ran, Wei Zhou, Wei Wang, Zongping Shao 2023, 83(8): 189-208.  DOI: 10.1016/j.jechem.2023.04.025 Abstract ( 28 )   PDF (16222KB) ( 14 )   Perovskite solar cells (PSCs) as a rising star in the photovoltaic field have received rapidly increasing attention recently due to the boosting power conversion efficiencies (PCEs) from 3.8% to 25.7% in the last 13 years. Nevertheless, the conventional PSCs with three-dimensional (3D) halide perovskites as light absorbers suffer from inferior PCEs and poor durability under sunlight, high-temperature and humid conditions due to the high defect amount and structural instability of 3D perovskites, respectively. To tackle these crucial issues, lower-dimensional halide perovskites including zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) perovskites have been employed as efficient passivators to boost the PCEs and durability of 3D-PSCs due to the high structural stability and superior resistance against moisture, heat and sunlight. Therefore, in order to achieve better understanding about the advantages and superiorities of combining low-dimensional perovskites with their 3D counterparts in improving the PCEs and durability of 3D-PSCs, the recent advances in the development and fabrication of mixed-dimensional PSCs with 1D/0D perovskites as passivators are summarized and discussed in the review. The superiority of 1D/0D perovskites as passivators over 2D counterparts, the passivation mechanism and the methods of 1D/0D perovskites are also presented and discussed. Furthermore, the rules to choose 1D/0D perovskites or relevant spacer cations are also emphasized. On this basis, several specific strategies to design and fabricate mixed-dimensional PSCs with 1D/0D perovskites are presented and discussed. Finally, the crucial challenges and future research directions of mixed-dimensional PSCs with 1D/0D perovskites as passivators are also proposed and discussed. This review will provide some useful insights for the future development of high-efficiency and durable mixed-dimensional PSCs.

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Toward stable and highly reversible zinc anodes for aqueous batteries via electrolyte engineering Ang Li, Jiayi Li, Yurong He, Maochun Wu 2023, 83(8): 209-228.  DOI: 10.1016/j.jechem.2023.04.006 Abstract ( 11 )   PDF (18167KB) ( 5 )   Featuring low cost, high abundance, low electrochemical potential, and large specific capacity, zinc (Zn) metal holds great potential as an anode material for next-generation rechargeable aqueous batteries. However, the poor reversibility resulting from dendrite formation and side reactions poses a major obstacle for its practical application. Electrolyte, which is regarded as the “blood” of batteries, has a direct impact on reaction kinetics, mass transport, and side reactions and thus plays a key role in determining the electrochemical performance of Zn electrodes. Therefore, considerable efforts have been devoted to modulating the electrolytes to improve the performance of Zn electrodes. Although significant progress has been made, achieving stable and highly reversible Zn electrodes remains a critical challenge. This review aims to provide a systematic summary and discussion on electrolyte strategies for high-performance aqueous Zn batteries. The (electro)-chemical behavior and fundamental challenges of Zn electrodes in aqueous electrolytes are first discussed. Electrolyte modulation strategies developed to address these issues are then classified and elaborated according to the underlying mechanisms. Finally, remaining challenges and promising future research directions on aqueous electrolyte engineering are highlighted. This review offers insights into the design of highly efficient electrolytes for new generation of rechargeable Zn batteries.

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Lithium plating-free 1 Ah-level high-voltage lithium-ion pouch battery via ambi-functional pentaerythritol disulfate Dung Tien Tuan Vu, Jinsol Im, Jae-Hee Kim, Jisoo Han, Gyeong Jun Chung, Giang Thi Huong Nguyen, Junhyeok Seo, Minjae Kim, Eui-Hyung Hwang, Young-Gil Kwon, Jae Wook Shin, Kuk Young Cho, Seung-Wan Song 2023, 83(8): 229-238.  DOI: 10.1016/j.jechem.2023.04.012 Abstract ( 15 )   PDF (11726KB) ( 8 )   Elevating the charge cut-off voltage beyond traditional 4.2 V is a commonly accepted technology to increase the energy density of Li-ion batteries (LIBs) but the risk of Li-dendrites and fire hazard increases as well. The use of ambi-functional additive, which forms stable solid electrolyte interphase (SEI) simultaneously at both cathode and anode, is a key to enabling a dendrites-free and well-working high-voltage LIB. Herein, a novel ambi-functional additive, pentaerythritol disulfate (PEDS), at 1 wt% without any other additive is demonstrated. We show the feasibility and high impacts of PEDS in forming lithium sulfate-incorporated robust SEI layers at NCM523 cathode and graphite anode in 1 Ah-level pouch cell under 4.4 V, 25 °C and 0.1 C rate, which mitigates the high-voltage instability, metal-dissolution and cracks on NCM523 particles, and prevents Li-dendrites at graphite anode. Improved capacity retention of 83% after 300 cycles is thereby achieved, with respect to 69% with base electrolyte, offering a promising path toward the design of practical high-energy LIBs.

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Electrode-compatible fluorine-free multifunctional additive regulating solid electrolyte interphase and solvation structure for high-performance lithium-ion batteries Qing-Song Liu, Yi-Zhou Quan, Mei-Chen Liu, Guo-Rui Zhu, Xiu-Li Wang, Gang Wu, Yu-Zhong Wang 2023, 83(8): 239-246.  DOI: 10.1016/j.jechem.2023.04.021 Abstract ( 7 )   PDF (8270KB) ( 5 )   The rapid development and widespread application of lithium-ion batteries (LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and performance on LIBs, significant challenges remain. Herein, a novel phosphorus-containing organic small molecule, bis(2-methoxyethyl) methylphosphonate (BMOP), was rationally designed to serve as a fluorine-free and multifunctional additive in commercial electrolytes. This novel electrolyte additive is low-toxicity, high-efficiency, low-cost, and electrode-compatible, which shows the significant improvement to both electrochemical performance and fire safety for LIBs through regulating the electrolyte solvation structure, constructing the stable electrode-electrolyte interphase, and suppressing the electrolyte combustion. This work provides a new avenue for developing safer and high-performance LIBs.

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Standard-state entropies and their impact on the potential-dependent apparent activation energy in electrocatalysis Kai S. Exner 2023, 83(8): 247-254.  DOI: 10.1016/j.jechem.2023.04.020 Abstract ( 6 )   PDF (4270KB) ( 18 )   The apparent activation energy, Eapp, is a common measure in thermal catalysis to discuss the activity and limiting steps of catalytic processes on solid-state materials. Recently, the electrocatalysis community adopted the concept of Eapp and combined it with the Butler-Volmer theory. Certain observations though, such as potential-dependent fluctuations of Eapp, are yet surprising because they conflict with the proposed linear decrease in Eapp with increasing overpotential. The most common explanation for this finding refers to coverage changes upon alterations in the temperature or the applied electrode potential. In the present contribution, it is demonstrated that the modulation of surface coverages cannot entirely explain potential-dependent oscillations of Eapp, and rather the impact of entropic contributions of the transition states has been overlooked so far. In the case of a nearly constant surface coverage, these entropic contributions can be extracted by a dedicated combination of Tafel plots and temperature-dependent experiments.

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RuO2-PdO nanowire networks with rich interfaces and defects supported on carbon toward the efficient alkaline hydrogen oxidation reaction Yuanyuan Cong, Fanchao Meng, Haibin Wang, Di Dou, Qiuping Zhao, Chunlei Li, Ningshuang Zhang, Junying Tian 2023, 83(8): 255-263.  DOI: 10.1016/j.jechem.2023.03.057 Abstract ( 11 )   PDF (12938KB) ( 3 )   Interfacial engineering is a promising approach for enhancing electrochemical performance, but rich and efficient interfacial active sites remain a challenge in fabrication. Herein, RuO2-PdO heterostructure nanowire networks (NWs) with rich interfaces and defects supported on carbon (RuO2-PdO NWs/C) for alkaline hydrogen oxidation reaction (HOR) was formed by a seed induction-oriented attachment-thermal treatment method for the first time. As expected, the RuO2-PdO NWs/C (72.8% Ru atomic content in metal) exhibits an excellent activity in alkaline HOR with a mass specific exchange current density (j0,m) of 1061 A gRuPd-1, which is 3.1 times of commercial Pt/C and better than most of the reported non-Pt noble metal HOR electrocatalysts. Even at the high potential (∼0.5 V vs. RHE) or the presence of CO (5 vol%), the RuO2-PdO NWs/C still effectively catalyzes the alkaline HOR. Structure/electrochemical analysis and theoretical calculations reveal that the interfaces between RuO2 and PdO act as the active sites. The electronic interactions between the two species and the rich defects for the interfacial active sites weaken the adsorption of Had, also strengthen the adsorption of OHad, and accelerate the alkaline HOR process. Moreover, OHad on RuO2 can spillover to the interfaces, keeping the RuO2-PdO NWs/C with the stable current density at higher potential and high resistance to CO poisoning.

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Atomically dispersed Fe-Ni dual sites in heteroatom doped carbon tyres for efficient oxygen electrocatalysis in rechargeable Zn-Air battery Zili Wang, Caiyun Li, Yukun Liu, Yu Wu, Sen Zhang, Chao Deng 2023, 83(8): 264-274.  DOI: 10.1016/j.jechem.2023.03.047 Abstract ( 3 )   PDF (16310KB) ( 1 )   The electronic and functional synergies between the twin metal centers make dual single-atom catalysts (DACs) attractive for oxygen electrocatalysis. The catalytic activities of DACs are largely decided by their surrounding micro-environment and supporting substrates. Modulating the micro-environment as well as engineering the efficient support is challenging tasks. Moreover, both are critical to optimizing the performance of DACs. Herein, a novel bio-cooperative strategy is developed to synthesize FeNi-DAC wherein Fe-Ni dual-atom sites are embedded in the N, P codoped tyre shaped carbon matrix. The configuration matching of Fe-Ni dual centers together with the local electronic engineering of N, P heteroatoms synergistically boost the catalytic activity on the oxygen reaction. Furthermore, the central-hollow highly-porous carbon matrix not only gives rise to a large amount of active sites, but also facilitates fast kinetics. Taking advantage of both the DAC and the substrate, the FeNi-NPC hollow tyre (HT) catalyst scores high in both oxygen reduction and evolution reactions, which exhibits the narrow potential difference and excellent durability. The aqueous Zn-air full battery (ZAB) integrating the FeNi-NPC HT air cathode has a high power density and a good stability over long-term cycling. Moreover, the flexible solid-state ZAB assembled with the polymer electrolyte obtains the high reliability over a wide range of temperatures or under diverse outside deformations. Therefore, this work offers a new green approach to prepare highly efficient DACs with built-in modulated micro-environment and tailor-made substrates. Moreover, it also paves a new way to develop highly-pliable power source for flexible electronics.

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High yield production of 1,4-cyclohexanediol from lignin derived 2,6-dimethoxybenzoquinone via Raney NiMn catalyst in hydrogen free conditions Zhe-Hui Zhang, Xianyuan Wu, Xiaohong Ren, Zeming Rong, Zhuohua Sun, Katalin Barta, Tong-Qi Yuan 2023, 83(8): 275-286.  DOI: 10.1016/j.jechem.2023.04.023 Abstract ( 10 )   PDF (12681KB) ( 1 )   Transformation of lignin to valuable chemicals via sustainable pathways is recognized as one of the most efficient ways to explore its value and replace the nonrenewable petroleum resource. In this work, an environmental-friendly transfer hydrogenation process has been developed to convert lignin derived 2,6-dimethoxybenzoquinone to 1,4-cyclohexanediol. Compared with previous work under hydrogen pressure (30 bar), this process uses isopropanol as both solvent and hydrogen donor, which significantly simply the operation process. The core of this study is the design and preparation of Mn modified Raney Ni catalysts by ball milling process. A series of Raney NiMn catalysts with different ball milling time and Mn content were prepared and investigated. Characterizations by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM) etc. showed that NiMnAl alloy was formed during the ball milling process and then transformed to NiMn alloy after treatment by aqueous NaOH. After optimization, a yield as high as 86.1% could be achieved for 1,4-cyclohexanediol at 200 °C in only 1 h.

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Recent advances in interfacial modification of zinc anode for aqueous rechargeable zinc ion batteries Qing Wen, Hao Fu, Ru-de Cui, He-Zhang Chen, Rui-Han Ji, Lin-Bo Tang, Cheng Yan, Jing Mao, Ke-Hua Dai, Xia-Hui Zhang, Jun-Chao Zheng 2023, 83(8): 287-303.  DOI: 10.1016/j.jechem.2023.03.059 Abstract ( 25 )   PDF (19584KB) ( 14 )   To tackle energy crisis and achieve sustainable development, aqueous rechargeable zinc ion batteries have gained widespread attention in large-scale energy storage for their low cost, high safety, high theoretical capacity, and environmental compatibility in recent years. However, zinc anode in aqueous zinc ion batteries is still facing several challenges such as dendrite growth and side reactions (e.g., hydrogen evolution), which cause poor reversibility and the failure of batteries. To address these issues, interfacial modification of Zn anodes has received great attention by tuning the interaction between the anode and the electrolyte. Herein, we present recent advances in the interfacial modification of zinc anode in this review. Besides, the challenges of reported approaches of interfacial modification are also discussed. Finally, we provide an outlook for the exploration of novel zinc anode for aqueous zinc ion batteries. We hope that this review will be helpful in designing and fabricating dendrite-free and hydrogen-evolution-free Zn anodes and promoting the practical application of aqueous rechargeable zinc ion batteries.

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Sub-nanometer Pt2In3 intermetallics as ultra-stable catalyst for propane dehydrogenation Yanan Xing, Guiyue Bi, Xiaoli Pan, Qike Jiang, Yuanlong Tan, Yang Su, Leilei Kang, Bonan Li, Lin Li, Aiqin Wang, Jingyuan Ma, Xiaofeng Yang, Xiao Yan Liu, Tao Zhang 2023, 83(8): 304-312.  DOI: 10.1016/j.jechem.2023.04.019 Abstract ( 7 )   PDF (7644KB) ( 4 )   Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation (PDH), which still suffer from insufficient long-term durability due to the structural instability and coke deposition. A commercial γ-Al2O3 supported thermally robust sub-nanometer Pt2In3 intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated, which showed outstanding robustness in 240 h long-term operation at 600 °C with the deactivation rate constant kd as low as 0.00078 h-1, ranking among the lowest reported values. Based on various in situ characterizations and theoretical calculations, it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms. An increasing distance to 3.25 Å in the Pt2In3 could induce a weak π-adsorption configuration of propylene on Pt sites, which facilitated the desorption of propylene and restrained the side reactions like coking.

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Activating coordinative conjugated polymer via interfacial electron transfer for efficient CO2 electroreduction Jing Zhang, Jia-Jun Dai, De-Quan Cao, Heng Xu, Xing-Yu Ding, Chun-Hua Zhen, Beate Paulus, Jin-Yu Ye, Qian Liang, Jun-Ke Liu, Shi-Jun Xie, Sai-Sai Deng, Zhen Wang, Jun-Tao Li, Yao Zhou, Shi-Gang Sun 2023, 83(8): 313-323.  DOI: 10.1016/j.jechem.2023.04.030 Abstract ( 3 )   PDF (13260KB) ( 1 )   With tunable local electronic environment, high mass density of MN4 sites, and ease of preparation, metal-organic conjugated coordinative polymer (CCP) with inherent electronic conductivity provides a promising alternative to the well-known M-N-C electrocatalysts. Herein, the coordination reaction between Cu2+ and 1,2,4,5-tetraaminobenzene (TAB) was conducted on the surface of metallic Cu nanowires, forming a thin layer of CuN4-based CCP (Cu-TAB) on the Cu nanowire. More importantly, interfacial transfer of electrons from Cu core to the CuN4-based CCP nanoshell was observed within the resulting CuTAB@Cu, which was found to enrich the local electronic density of the CuN4 sites. As such, the CuTAB@Cu demonstrates much improved affinity to the *COOH intermediate formed from the rate determining step; the energy barrier for C-C coupling, which is critical to convert CO2 into C2 products, is also decreased. Accordingly, it delivers a current density of -9.1 mA cm-2 at a potential as high as -0.558 V (vs. RHE) in H-type cell and a Faraday efficiency of 46.4% for ethanol. This work emphasizes the profound role of interfacial interaction in tuning the local electronic structure and activating the CuN4-based CCPs for efficient electroreduction of CO2.

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Cell-nucleus structured electrolyte for low-temperature aqueous zinc batteries Yang Dong, Ning Zhang, Zhaodong Wang, Jinhan Li, Youxuan Ni, Honglu Hu, Fangyi Cheng 2023, 83(8): 324-332.  DOI: 10.1016/j.jechem.2023.04.017 Abstract ( 11 )   PDF (10721KB) ( 3 )   Rechargeable aqueous zinc (Zn) batteries hold great promise for large-scale energy storage, but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance. Herein, we design a cell-nucleus structured electrolyte by introducing low-polarity 1,2-dimethoxyethane (DME) into dilute 1 M zinc trifluoromethanesulfonate (Zn(OTf)2) aqueous solution, which features an OTf--rich Zn2+-primary solvation sheath (PSS, inner nucleus) and the DME-modulated Zn2+-outer solvation sheath (outer layer). We find that DME additives with a low dosage do not participate in the Zn2+-PSS but reinforce the Zn-OTf- coordination, which guarantees good reaction kinetics under ultralow temperatures. Moreover, DME breaks the original H-bonding network of H2O, depressing the freezing point of electrolyte to -52.4 °C. Such a cell-nucleus-solvation structure suppresses the H2O-induced side reactions and forms an anion-derived solid electrolyte interphase on Zn and can be readily extended to 1,2-diethoxyethane. The as-designed electrolyte enables the Zn electrode deep cycling stability over 3500 h with a high depth-of-discharge of 51.3% and endows the Zn||V2O5 full battery with stable cycling over 1000 cycles at -40 °C. This work would inspire the solvation structure design for low-temperature aqueous batteries.

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Rapid and durable oxygen reduction reaction enabled by a perovskite oxide with self-cleaning surface Shengli Pang, Yifan Song, Meng Cui, Xin Tang, Chao Long, Lingfeng Ke, Gongmei Yang, Ting Fang, Yong Guan, Chonglin Chen 2023, 83(8): 333-340.  DOI: 10.1016/j.jechem.2023.04.038 Abstract ( 11 )   PDF (10342KB) ( 12 )   The growth of electrochemically inert segregation layers on the surface of solid oxide fuel cell cathodes has become a bottleneck restricting the development of perovskite-structured oxygen reduction catalysts. Here, we report a new discovery in which enriched Ba and Fe ions on the near-surface of Nd1/2Ba1/2Co1/3Fe1/3Mn1/3O3-δ spontaneously agglomerate into dispersed Ba5Fe2O8 nanoparticles and maintain a highly active and durable perovskite structure on the surface. This unique surface self-cleaning phenomenon is related to the low average potential energy of Ba5Fe2O8, which is grown on the near-surface layer. The electrochemically inert Ba5Fe2O8 segregation layer on the near-surface of the perovskite catalyst achieves self-cleaning by regulating the formation energy of enriched metal oxides. This self-cleaned perovskite surface exhibits an ultrafast oxygen exchange rate, high catalytic activity for the oxygen reduction reaction, and good adaptability to the actual working conditions of solid oxide fuel cell stacks. This study paves a new way for overcoming the stubborn problem of perovskite catalyst surface deactivation and enriches the scientific knowledge of surface catalysis.

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Engineering versatile Au-based catalysts for solar-to-fuel conversion Chunhua Wang, Hongwen Zhang, Feili Lai, Zhirun Xie, Yun Hau Ng, Bo Weng, Xuejiao Wu, Yuhe Liao 2023, 83(8): 341-362.  DOI: 10.1016/j.jechem.2023.04.027 Abstract ( 13 )   PDF (10193KB) ( 2 )   Gold (Au) nanostructures (NSs) have been widely employed as cocatalysts to improve the photoactivity of semiconductor materials, while a systematic summary of the engineering approaches of Au NSs to maximize the solar-to-fuel conversion efficiency is still lacking. In this review, the recently developed strategies for elevating the overall photocatalytic performance of Au-based catalysts and the deep physical chemistry mechanisms are highlighted. Firstly, the synthetic approaches of Au NSs are summarized, followed by an elaboration on their multiple functions in improving photoactivity. Afterward, modification strategies of Au NSs used to enhance the photocatalytic efficiency of Au-semiconductor composites, including controlling the Au NSs morphology, size, crystal phase, defect engineering, alloying with different metals, modulating interfacial interaction, and introducing an external field, are summarized and discussed independently. Additionally, advanced characterization techniques that can provide insights into the charge dynamics of the photocatalysts are introduced. Finally, we share our opinion on the challenges and outline potentially promising opportunities and directions for efficient Au-based photocatalysis research moving forward. We sincerely look forward to this review can deliver insightful views to design efficient Au-based photocatalysts and spur certain innovations to other metal-based catalysts.

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For more and purer hydrogen-the progress and challenges in water gas shift reaction Limin Zhou, Yanyan Liu, Shuling Liu, Huanhuan Zhang, Xianli Wu, Ruofan Shen, Tao Liu, Jie Gao, Kang Sun, Baojun Li, Jianchun Jiang 2023, 83(8): 363-396.  DOI: 10.1016/j.jechem.2023.03.055 Abstract ( 18 )   PDF (52370KB) ( 7 )   The water gas shift (WGS) reaction is a standard reaction that is widely used in industrial hydrogen production and removal of carbon monoxide. The improved catalytic performance of WGS reaction also contributes to ammonia synthesis and other reactions. Advanced catalysts have been developed for both high and low-temperature reactions and are widely used in industry. In recent years, supported metal nanoparticle catalysts have been researched due to their high metal utilization. Low-temperature catalysts have shown promising results, including high selectivity, high shift rates, and higher activity potential. Additionally, significant progress has been made in removing trace CO through the redox reaction in electrolytic cell. This paper reviews the development of WGS reaction catalysts, including the reaction mechanism, catalyst design, and innovative research methods. The catalyst plays a crucial role in the WGS reaction, and this paper provides an instant of catalyst design under different conditions. The progress of catalysts is closely related to the development of advanced characterization techniques. Furthermore, modifying the catalyst surface to enhance activity and significantly increase reaction kinetics is a current research direction. This review goals to stimulate a better understanding of catalyst design, performance optimization, and driving mechanisms, leading to further progress in this field.

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Development strategies and improved photocatalytic CO2 reduction performance of metal halide perovskite nanocrystals Xianwei Fu, Tingting Ren, Shilong Jiao, Zhihong Tian, Jianjun Yang, Qiuye Li 2023, 83(8): 397-422.  DOI: 10.1016/j.jechem.2023.04.028 Abstract ( 9 )   PDF (26534KB) ( 4 )   In recent years, photocatalytic CO2 reduction reaction (CRR) has attracted much scientific attention to overcome energy and environmental issues by converting CO2 into high-value-added chemicals utilizing solar energy. Metal halide perovskite (MHP) nanocrystals (NCs) are recognized as an ideal choice for CRR owing to their outstanding optoelectronic properties. Although great efforts have been devoted to designing more effective photocatalysts to optimize CRR performance, severe charge recombination, instability, and unsatisfactory activity have become major bottlenecks in developing perovskite-based photocatalysts. In this review, we mainly focus on the recent research progress in the areas of relevance. First, a brief insight into reaction mechanisms for CRR and structural features of MHPs are introduced. Second, efficient modification approaches for the improvement of the photocatalytic activity and stability of the perovskite-based catalysts are comprehensively reviewed. Third, the state-of-the-art achievements of perovskite-based photocatalysts for CRR are systematically summarized and discussed, which are focused on the modification approaches, structure design, and the mechanism of the CO2 reduction process. Lastly, the current challenges and future research perspectives in the design and application of perovskite materials are highlighted from our point of view to provide helpful insights for seeking breakthroughs in the field of CRR. This review may provide a guide for scientists interested in applying perovskite-based catalysts for solar-to-chemical energy conversion.

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Novel carbon-nitride based catalysts for enhanced CH4 reforming under visible light: From morphology to heterojunction design principles Yufei Huang, Ding Wei, Ziyi Li, Yu Mao, Yangqiang Huang, Bo Jin, Xiao Luo, Zhiwu Liang 2023, 83(8): 423-432.  DOI: 10.1016/j.jechem.2023.04.008 Abstract ( 7 )   PDF (10492KB) ( 5 )   The synthesis of high value-added chemical products using CO2 and CH4 is a promising CO2 conversion technology that can reduce greenhouse gas emissions while also alleviating the energy crisis. However, problems such as high energy consumption and strict reaction conditions in reforming process hinder the further development of the technology. In this work, carbon-nitrogen based composites were prepared for the first time according to the design principle from morphology to heterojunction, which is innovatively applied in the process of photocatalytic CH4 reforming. Firstly, C3N4 materials with different dimensions (D) are prepared and applied to a CO2-CH4 photocatalytic system. Additionally, the 2D/2D TiO2/g-C3N4 heterostructure is constructed with the ultrasonic impregnation method to further improve charge generation, transfer, and separation efficiency. It is worth noting that the yield of CO reaches 173.80 μmol g-1, and the catalytic performance is improved by 1546% compared to bulk C3N4. Moreover, the physical and chemical properties of 2D/2D TiO2/g-C3N4 materials are studied using a variety of characterization methods. Furthermore, the work function and adsorption energy of different C3N4/TiO2 models for CO2 adsorption are calculated by density functional theory (DFT). Then, a possible catalytic mechanism for photocatalytic CO2 and CH4 conversion is proposed based on DFT calculations and experimental results. This work provides a new technical route for the rapid conversion of CO2 and CH4 at room temperature, as well as a new research concept for achieving carbon neutrality.

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Reducing voltage hysteresis of metal oxide anodes to achieve high energy efficiency for Li-ion batteries Xuexia Lan, Xingyu Xiong, Jie Cui, Renzong Hu 2023, 83(8): 433-444.  DOI: 10.1016/j.jechem.2023.05.002 Abstract ( 9 )   PDF (16042KB) ( 2 )   In the past two decades, a lot of high-capacity conversion-type metal oxides have been intensively studied as alternative anode materials for Li-ion batteries with higher energy density. Unfortunately, their large voltage hysteresis (0.8-1.2 V) within reversed conversion reactions results in huge round-trip inefficiencies and thus lower energy efficiency (50%-75%) in full cells than those with graphite anodes. This remains a long-term open question and has been the most serious drawback toward application of metal oxide anodes. Here we clarify the origins of voltage hysteresis in the typical SnO2 anode and propose a universal strategy to minimize it. With the established in situ phosphating to generate metal phosphates during reversed conversion reactions in synergy with boosted reaction kinetics by the added P and Mo, the huge voltage hysteresis of 0.9 V in SnO2, SnO2-Mo, and 0.6 V in SnO2-P anodes is minimized to 0.3 V in a ternary SnO2-Mo-P (SOMP) composite, along with stable high capacity of 936 mA h g-1 after 800 cycles. The small voltage hysteresis can remain stable even the SOMP anode operated at high current rate of 10 A g-1 and wide-range temperatures from 60 to -30 °C, resulting in a high energy efficiency of 88.5% in full cells. This effective strategy to minimize voltage hysteresis has also been demonstrated in Fe2O3, Co3O4-basded conversion-type anodes. This work provides important guidance to advance the high-capacity metal oxide anodes from laboratory to industrialization.

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Intrinsic thermal stability of inverted perovskite solar cells based on electrochemical deposited PEDOT Congtan Zhu, Jing Gao, Tian Chen, Xueyi Guo, Ying Yang 2023, 83(8): 445-453.  DOI: 10.1016/j.jechem.2023.04.039 Abstract ( 17 )   PDF (17022KB) ( 4 )   Thermal stability of perovskite materials is an issue impairing the long-term operation of inverted perovskite solar cells (PSCs). Herein, the thermal attenuation mechanism of the MAPbI3 films that deposited on two different hole transport layers (HTL), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly(3,4-ethylenedioxythiophene) (PEDOT), is comprehensively studied by applying a heat treatment at 85 °C. The thermal stress causes the mutual ions migration of I, Pb and Ag through the device, which leads to the thermal decomposition of perovskite to form PbI2. Interestingly, we find that I ions tend to migrate more towards electron transport layer (ETL) during heating, which is different with the observation of I ions migration towards HTL when bias pressure is applied. Moreover, the use of electrochemical deposited PEDOT as HTL significantly decreases the defect density of MAPbI3 films as compared to PEDOT:PSS supported one. The electrochemical deposition PEDOT has good carrier mobility and low acidity, which avoids the drawbacks of aqueous PEDOT:PSS. Accordingly, the inverted PSCs based on PEDOT show superior durability than that with PEDOT:PSS. Our results reveal detailed degradation routes of a new kind of inverted PSCs which can contribute to the understanding of the failure of thermal-aged inverted PSCs.

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Harnessing dimethyl ether and methyl formate fuels for direct electrochemical energy conversion Medhanie Gebremedhin Gebru, Radhey Shyam Yadav, Hanan Teller, Haya Kornweitz, Palaniappan Subramanian, Alex Schechter 2023, 83(8): 454-464.  DOI: 10.1016/j.jechem.2023.05.001 Abstract ( 11 )   PDF (6717KB) ( 6 )   In this work, the oxidation of a mixture of dimethyl ether (DME) and methyl formate (MF) was studied in both an aqueous electrochemical cell and a vapor-fed polymer electrolyte membrane fuel cell (PEMFC) utilizing a multi-metallic alloy catalyst, Pt3Pd3Sn2/C, discovered earlier by us. The current obtained during the bulk oxidation of a DME-saturated 1 M MF was higher than the summation of the currents provided by the two fuels separately, suggesting the cooperative effect of mixing these fuels. A significant increase in the anodic charge was realized during oxidative stripping of a pre-adsorbed DME + MF mixture as compared to DME or MF individually. This is ascribed to greater utilization of specific catalytic sites on account of the relatively lower adsorption energy of the dual- molecules than of the sum of the individual molecules as confirmed by the density functional theory (DFT) calculations. Fuel cell polarization was also conducted using a Pt3Pd3Sn2/C (anode) and Pt/C (cathode) catalysts-coated membrane (CCM). The enhanced surface coverage and active site utilization resulted in providing a higher peak power density by the DME + MF mixture-fed fuel cell (123 mW cm-2 at 0. 45 V) than with DME (84 mW cm-2 at 0.35 V) or MF (28 mW cm-2 at 0.2 V) at the same total anode hydrocarbon flow rate, temperature, and ambient pressure.

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Fast charge transport motivated by tunable Mo2C/Mo2N high-quality heterointerface for superior pseudocapacitive storage Yanjun Gao, Shaohua Zhang, Lingrui Xu, Xiangyang Li, Lijie Li, Lixia Bao, Jiong Peng, Xin Li 2023, 83(8): 465-477.  DOI: 10.1016/j.jechem.2023.04.035 Abstract ( 6 )   PDF (11866KB) ( 2 )   The development of potential transition-metal carbide/nitride heterojunctions is hindered by overall understanding and precise modulation for heterointerface effects. Herein, we demonstrate that Mo2C/Mo2N heterojunction with the precisely regulated high-quality interface can achieve marvelous rate performance and energy output via enlarging the interface-effect range and maximizing “accelerated charge” amount. The heterointerface mechanism improving properties is synergistically revealed from kinetics and thermodynamics perspectives. Kinetics analysis confirms that the self-built electric field affords a robust force to drive rapid interface electrons/ions migration. The small adsorption energy, high density of states and quite low diffusion barrier thermodynamically enhance the electrochemical reaction dynamics on heterointerface. Consequently, the almost optimal performance of ultrahigh capacitance retention (85.6% even at 10 A g-1) and pronounced energy output (96.4 Wh kg-1) in hybrid-supercapacitors than other Mo2C/Mo2N-based materials is presented. This work gives new insight into the energy storage mechanism of heterojunction and guides the design of advanced electrodes.

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Triboelectric nanogenerator based on electrodeposited Ag octahedral nano-assemblies M. Edith Navarro-Segura, Margarita Sánchez-Domínguez, Ana Arizmendi-Morquecho, J. Alvarez-Quintana 2023, 83(8): 478-495.  DOI: 10.1016/j.jechem.2023.04.041 Abstract ( 3 )   PDF (27026KB) ( 1 )   The tremendous potential of triboelectric generators-TENGs for converting mechanical energy into electrical energy places them as one of the most promising energy harvesting technologies. In this work, the fabrication of enhanced performance TENGs using Ag octahedron nano-assemblies on ITO as electrodes significantly increases the electric charge collection of the induced tribocharges. Thereby, nanostructured electrical contacts coated with Ag macroscale nano-assemblies with octahedral features were obtained by the electrodeposition technique on flexible PET/ITO substrates. Consequently, the nanostructured triboelectric generator-TENG exhibited 65 times more maximum output power, and almost 10 times more open circuit output voltage than that of a TENG with non-nanostructured contacts passing from μW to mW capabilities, which was attributed to the increment of intrinsic interface states due to a higher effective contact area in the former. Likewise, output performances of TENGs also displayed an asymptotic behavior on the output voltage as the operating frequency of the mechanical oscillations increased, which is attributed to a decrement in the internal impedance of the device with frequency. Furthermore, it is shown that the resulting electrical output power can successfully drive low power consumption electronic devices. On that account, the present research establishes a promising platform which contributes in an original way to the development of the TENGs technology.

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Optimally arranged TiO2@MoS2 heterostructures with effectively induced built-in electric field for high-performance lithium-sulfur batteries Jeongyoub Lee, Changhoon Choi, Jung Been Park, Seungho Yu, Jinho Ha, Hyungsoo Lee, Gyumin Jang, Young Sun Park, Juwon Yun, Hayoung Im, Subin Moon, Soobin Lee, Jung-Il Choi, Dong-Wan Kim, Jooho Moon 2023, 83(8): 496-508.  DOI: 10.1016/j.jechem.2023.04.016 Abstract ( 4 )   PDF (6163KB) ( 2 )   To overcome the serious technological issues affecting lithium-sulfur (Li-S) batteries, such as sluggish sulfur redox kinetics and the detrimental shuttle effect, heterostructure engineering has been investigated as a strategy to effectively capture soluble lithium polysulfide intermediates and promote their conversion reaction by integrating highly polar metal oxides with catalytically active metals sulfides. However, to fully exploit the outstanding properties of heterostructure-based composites, their detailed structure and interfacial contacts should be designed rationally. Herein, optimally arranged TiO2 and MoS2-based heterostructures (TiO2@MoS2) are fabricated on carbon cloth as a multifunctional interlayer to efficiently trap polysulfide intermediates and accelerate their redox kinetics. Owing to the synergistic effects between TiO2 and MoS2 and the uniform heterointerface distribution that induces the ideally oriented built-in electric field, Li-S batteries with TiO2@MoS2 interlayers exhibit high rate capability (601 mA h g-1 at 5 C), good cycling stability (capacity-fade rate of 0.067% per cycle over 500 cycles at 2 C), and satisfactory areal capacity (5.2 mA h cm-2) under an increased sulfur loading of 5.2 mg cm-2. Moreover, by comparing with a MoS2@TiO2 interlayer composed of reversely arranged heterostructures, the effect of the built-in electric field's direction on the electrocatalytic reactions of polysulfide intermediates is thoroughly investigated for the first time. The superior electrocatalytic activities of the rationally arranged TiO2@MoS2 interlayer demonstrate the importance of optimizing the built-in electric field of heterostructures for producing high-performance Li-S batteries.

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A review on anode materials for lithium/sodium-ion batteries Abhimanyu Kumar Prajapati, Ashish Bhatnagar 2023, 83(8): 509-540.  DOI: 10.1016/j.jechem.2023.04.043 Abstract ( 84 )   PDF (30748KB) ( 89 )   Since lithium-ion batteries (LIBs) have been substantially researched in recent years, they now possess exceptional energy and power densities, making them the most suited energy storage technology for use in developed and developing industries like stationary storage and electric cars, etc. Concerns about the cost and availability of lithium have prompted research into alternatives, such as sodium-ion batteries (SIBs), which use sodium instead of lithium as the charge carrier. This is especially relevant for stationary applications, where the size and weight of battery are less important. The working efficiency and capacity of these batteries are mainly dependent on the anode, cathode, and electrolyte. The anode, which is one of these components, is by far the most important part of the rechargeable battery. Because of its characteristics and its structure, the anode has a tremendous impact on the overall performance of the battery as a whole. Keeping the above in view, in this review we critically reviewed the different types of anodes and their performances studied to date in LIBs and SIBs. The review article is divided into three main sections, namely: (i) intercalation reaction-based anode materials; (ii) alloying reaction-based anode materials; and (iii) conversion reaction-based anode materials, which are further classified into a number of subsections based on the type of material used. In each main section, we have discussed the merits and challenges faced by their particular system. Afterward, a brief summary of the review has been discussed. Finally, the road ahead for better application of Li/Na-ion batteries is discussed, which seems to mainly depend on exploring the innovative materials as anode and on the in-operando characterization of the existing materials for making them more capable in terms of application in rechargeable batteries.

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Utilizing hybrid faradaic mechanism via catalytic and surface interactions for high-performance flexible energy storage system Dong-Gyu Lee, Hyeonggeun Choi, Yeonsu Park, Min-Cheol Kim, Jong Bae Park, Suok Lee, Younghyun Cho, Wook Ahn, A-Rang Jang, Jung Inn Sohn, John Hong, Young-Woo Lee 2023, 83(8): 541-548.  DOI: 10.1016/j.jechem.2023.04.031 Abstract ( 3 )   PDF (9037KB) ( 2 )   Improving the capacitance and energy density is a significant challenge while developing practical and flexible energy storage system (ESS). Redox mediators (RMs), as redox-active electrolyte additives, can provide additional energy storing capability via electrochemical faradaic contribution on electrodes for high-performance flexible ESSs. Particularly, determining effective material combinations between electrodes and RMs is essential for maximizing surface faradaic redox reactions for energy-storage performance. In this study, an electrode-RM system comprising heterostructured hybrid (carbon fiber (CF)/MnO2) faradaic electrodes and iodine RMs (I-RMs) in a redox-active electrolyte is investigated. The CF/MnO2 with the I-RMs (CF/MnO2-I) induces dominant catalytic faradaic interaction with the I-RMs, significantly enhancing the surface faradaic kinetics and increasing the overall energy-storage performance. The CF/MnO2-I ESSs show a 12.6-fold (or higher) increased volumetric energy density of 793.81 mWh L-1 at a current of 10 µA relative to ESSs using CF/MnO2 without I-RMs (CF/MnO2). Moreover, the CF/MnO2-I retains 93.1% of its initial capacitance after 10,000 cycles, validating the excellent cyclability. Finally, the flexibility of the ESSs is tested at different bending angles (180° to 0°), demonstrating its feasibility for flexible and high-wear environments. Therefore, CF/MnO2 electrodes present a practical material combination for high-performance flexible energy-storage devices owing to the catalytic faradaic interaction with I-RMs.

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Waste to wealth: Oxygen-nitrogen-sulfur codoped lignin-derived carbon microspheres from hazardous black liquors for high-performance DSSCs Wenjie Cheng, Caichao Wan, Xingong Li, Huayun Chai, Zhenxu Yang, Song Wei, Jiahui Su, Xueer Tang, Yiqiang Wu 2023, 83(8): 549-563.  DOI: 10.1016/j.jechem.2023.04.032 Abstract ( 3 )   PDF (13889KB) ( 1 )   Carbon materials are effective substitutes for Pt counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors, is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon, which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory (DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.

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Rational design of stretchable and conductive hydrogel binder for highly reversible SiP2 anode Xuhao Liu, Runzhe Yao, Siqi Wang, Yaqing Wei, Bin Chen, Wei Liang, Caiyun Tian, Chengyu Nie, De Li, Yong Chen 2023, 83(8): 564-573.  DOI: 10.1016/j.jechem.2023.04.037 Abstract ( 7 )   PDF (14582KB) ( 4 )   The emerging SiP2 with large capacity and suitable plateau is proposed to be the alternative anode for Li-ion batteries. However, typical SiP2 still suffers from serious volume expansion and structural destruction, resulting in much Li-consumption and capacity fading. Herein, a novel stretchable and conductive Li-PAA@PEDOT:PSS binder is rationally designed to improve the cyclability and reversibility of SiP2. Interestingly, such Li-PAA@PEDOT:PSS hydrogel enables a better accommodation of volume expansion than PVDF binder (e.g. 5.94% vs. 68.73% of expansivity). More specially, the SiP2 electrode with Li-PAA@PEDOT:PSS binder is surprisingly found to enable unexpected structural recombination and self-healing Li-storage processes, endowing itself with a high initial Coulombic efficiency (ICE) up to 93.8%, much higher than PVDF binder (ICE = 70.7%) as well. Such unusual phenomena are investigated in detail for Li-PAA@PEDOT:PSS, and the possible mechanism shows that its Li-PAA component enables to prevent the pulverization of SiP2 nanoparticles while the PEDOT:PSS greatly bridges fast electronic connection for the whole electrode. Consequently, after being further composited with carbon matrix, the SiP2/C with Li-PAA@PEDOT:PSS hydrogel exhibits high reversibility (ICE> 93%), superior cyclability (>450 cycles), and rate capability (1520 mAh/g at 2000 mA/g) for LIBs. This highly stretchable and conductive binder design can be easily extended to other alloying materials toward advanced energy storage.

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Rare earth alloy nanomaterials in electrocatalysis Yifei Li, Xilin Yuan, Ping Wang, Lulin Tang, Miao He, Pangen Li, Jiang Li, Zhenxing Li 2023, 83(8): 574-594.  DOI: 10.1016/j.jechem.2023.04.050 Abstract ( 17 )   PDF (13266KB) ( 13 )   With the rapid development of society and economy, the excessive consumption of fossil energy has led to the global energy and environment crisis. In order to explore the sustainable development of new energy, research based on electrocatalysis has attracted extensive attention in the academic circle. The main challenge in this field is to develop nano-catalysts with excellent electrocatalytic activity and selectivity for target products. The state of the active site in catalyst plays a decisive role in the activity and selectivity of the reaction. In order to design efficient and excellent catalysts, it is an effective means to adjust the electronic structure of catalysts. Electronic effects are also called ligand effects. By alloying with rare earth (RE) elements, electrons can be redistributed between RE elements and transition metal elements, achieving accurate design of the electronic structure of the active site in the alloy. Because of the unique electronic structure of RE, it has been paid attention in the field of catalysis. The outermost shell structure of RE elements is basically the same as that of the lower shell, except that the number of electrons in the 4f orbital is different, but the energy level is similar, so their properties are very similar. When RE elements form compounds, both the f electrons in the outermost shell and the d electrons in the lower outer shell can participate in bonding. In addition, part of the 4f electrons in the third outer shell can also participate in bonding. In order to improve the performance of metal catalysts, alloying provides an effective method to design advanced functional materials. RE alloys can integrate the unique electronic structure and catalytic behavior of RE elements into metal materials, which not only provides an opportunity to adjust the electronic structure and catalytic activity of the active component, but also enhances the structural stability of the alloy and is expected to significantly improve the catalytic performance of the catalyst. From the perspective of electronic and catalytic activity, RE elements have unique electronic configuration and lanthanide shrinkage effect. Alloying with RE elements will make the alloy have more abundant electronic structure, activity, and spatial arrangement, effectively adjusting the reaction kinetics of the electrochemical process of the catalyst. In this paper, the composition, structure, synthesis of RE alloys and their applications in the field of electrocatalysis are summarized, including the hydrogen evolution reaction, the oxygen evolution reaction, the oxygen reduction reaction, the methanol oxidation reaction, the ethanol oxidation reaction, and other catalytic reactions. At the same time, the present challenges of RE alloy electrocatalytic materials are summarized and their future development direction is pointed out. In the field of electrocatalysis, the cost of catalyst is too high and the stability is not strong. Therefore, the testing process should be related to the actual application, and the test method should be standardized, so as to carry forward the field of electrocatalysis.

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Nano-capillary induced assemble of quantum dots on perovskite grain boundaries for efficient and stable perovskite solar cells Miaoyu Lin, Jingjing He, Xinyi Liu, Qing Li, Zhanpeng Wei, Yuting Sun, Xuesong Leng, Mengjiong Chen, Zhuhui Xia, Yu Peng, Qiang Niu, Shuang Yang, Yu Hou 2023, 83(8): 595-601.  DOI: 10.1016/j.jechem.2023.05.006 Abstract ( 26 )   PDF (4705KB) ( 15 )   In recent years, perovskite solar cells (PSCs) have propelled into the limelight owing to rapid development of efficiency; however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss and structural degradation. Here, the grain boundaries of perovskite polycrystalline films have been found to act as nanocapillaries for capturing perovskite quantum dots (PQDs), which enable the conformal assemble of PQDs at the top interspace between perovskite grains. The existence of PQDs passivated the surface defects, optimized the interfacial band alignments, and ultimately improved the power conversion efficiency from 19.27% to 22.47% in inverted PSCs. Our findings open up the possibility of selective assembly and structural modulation of the perovskite nanostructures towards efficient and stable PSCs.

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Edge atomic Fe sites decorated porous graphitic carbon as an efficient bifunctional oxygen catalyst for Zinc-air batteries Ruihui Gan, Yali Wang, Xiangwu Zhang, Yan Song, Jingli Shi, Chang Ma 2023, 83(8): 602-611.  DOI: 10.1016/j.jechem.2023.03.056 Abstract ( 3 )   PDF (15087KB) ( 1 )   The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions (ORR and OER) is critical to the practical application of zinc-air batteries (ZABs). Herein, a silica-assisted method is reported to integrate numerous accessible edge Fe-Nx sites into porous graphitic carbon (named Fe-N-G) for achieving highly active and robust oxygen electrocatalysis. Silica facilitates the formation of edge Fe-Nx sites and dense graphitic domains in carbon by inhibiting iron aggregation. The purification process creates a well-developed mass transfer channel for Fe-N-G. Consequently, Fe-N-G delivers a half-wave potential of 0.859 V in ORR and an overpotential of 344 mV at 10 mA cm-2 in OER. During long-term operation, the graphitic layers protect edge Fe-Nx sites from demetallation in ORR and synergize with FeOOH species endowing Fe-N-G with enhanced OER activity. Density functional theory calculations reveal that the edge Fe-Nx site is superior to the in-plane Fe-Nx site in terms of OH* dissociation in ORR and OOH* formation in OER. The constructed ZAB based on Fe-N-G cathode shows a higher peak power density of 133 mW cm-2 and more stable cycling performance than Pt/C + RuO2 counterparts. This work provides a novel strategy to obtain high-efficiency bifunctional oxygen electrocatalysts through space mediation.

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Stable lithium metal anode enabled by a robust artificial fluorinated hybrid interphase Qiwen Ran, Hongyuan Zhao, Jintao Liu, Lei Li, Qiang Hu, Jiangxuan Song, Xingquan Liu, Sridhar Kormarneni 2023, 83(8): 612-621.  DOI: 10.1016/j.jechem.2023.04.047 Abstract ( 10 )   PDF (12234KB) ( 11 )   One of the key challenges for achieving stable lithium (Li) metal anode is the construction of the rational solid electrolyte interphase (SEI), but its realization still faces enormous challenges. In this work, a robust artificial fluorinated hybrid interphase consisting of lithium-bismuth (Li3Bi) alloy and lithium-fluoride (LiF) was designed to regulate Li deposition without Li dendrite growth. The obtained hybrid interphase showed the high Li+ diffusion rate (3.5 × 10-4 S cm-1), high electron resistivity (9.04 × 104 Ω cm), and high mechanical strength (1348 MPa), thus enabling the uniform Li deposition at the Li/SEI interface. Specifically, Li3Bi alloy, as a superionic conductor, accelerated the Li+ transport and stabilized the hybrid interphase. Meanwhile, LiF was identified as a superior electron-blocker to inhibit the electron tunneling from the Li anode into the SEI. As a result, the modified Li anode showed the stable Li plating/stripping behaviors over 1000 cycles even at 20 mA cm-2. Moreover, it also enabled the Li (50 μm)‖LiNi0.8Co0.1Mn0.1O2 (4.4 mA h cm-2) full cell to achieve an average Coulombic efficiency (CE) of 99.6% and a high-capacity retention of 79.2% after 100 cycles, whereas the bare Li anode only exhibited a low-capacity retention of 8.0%. This work sheds light on the internal mechanism of Li+ transport within the hybrid interface and provides an effective approach to stabilize the interface of Li metal anode.