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2020, Vol. 47, No. 8　Online: 2020-08-15

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Partial oxidation of methane over SiO2 supported Ni and NiCe catalysts A.Emamdoust, V.La Parola, G.Pantaleo, M.L.Testa, S.Farjami Shayesteh, A.M.Venezia 2020, 47(8): 1-9.  DOI: 10.1016/j.jechem.2019.11.019 摘要 ( 10 )   Nickel and nickel-ceria catalysts supported on high surface area silica.with 6 wt% Ni and 20 wt% CeO2 were prepared by microwave assisted (co) precipitation method.The catalysts were investigated by XRD.TPR and XPS analyses and they were tested in partial oxidation of methane (CPO).The catalytic reaction was carried out at atmospheric pressure in a temperature range of 400-800℃ with a feed gas mixture containing methane and oxygen in a molecular ratio CH4/O2=2.The Ni catalyst exhibited 60% methane conversion with 60% selectivity to CO already at 500℃.On the contrary.the Ni-Ce catalyst was inert to CPO up to 700℃.Moreover.the former catalyst reproduced its activity at the descending temperatures maintaining a good stability at 600℃.over a reaction time of 80 h.whereas the latter one completely deactivated.Test of CH4 temperature programmed surface reaction (CH4-TPSR) revealed a higher methane activation temperature (> 100℃) for the Ni-Ce catalyst as compared to the Ni one.Noticeable improvement of the ceria containing catalyst occurred when the reaction test started at a temperature higher than the methane decomposition temperature.In this case.the sample achieved the same catalytic behavior of the Ni catalyst.As confirmed by XPS analyses.the distinct electronic state of the supported nickel was responsible for the differences in catalytic behavior.

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The donor-dependent methoxy effects on the performance of hole-transporting materials for perovskite solar cells Mengyuan Li, Jinhua Wu, Guoguo Wang,bingxue Wu, Zhe Sun, Song Xue, Qiquan Qiao, Mao Liang 2020, 47(8): 10-17.  DOI: 10.1016/j.jechem.2019.11.017 摘要 ( 11 )   In this work.a comprehensive study on the deliberate molecular design and modifications of electron donors is carried out to elucidate correlations between the methoxy effects and donor configuration of hole-transporting materials (HTMs).Our initial findings demonstrate the donor-dependent methoxy effects.Photovoltaic performance of the HTM with twisted donor highly depends on the methoxy substituent.In contrast.efficiency's reliance on methoxy is insignificant for the HTM with planar donor.The HTM (M123) featuring the methoxy-substituted carbazole shows a decent power conversion efficiency of 19.33% due to synergistic effects from both planar structure and methoxy.This work gives a guideline to access HTMs reaching both high-performance and good stability.

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An investigation of Zr/Ce ratio influencing the catalytic performance of CuO/Ce1-xZrxO2 catalyst for CO2 hydrogenation to CH3OH Weiwei Wang, Zhenping Qu, Lixin Song, Qiang Fu 2020, 47(8): 18-28.  DOI: 10.1016/j.jechem.2019.11.021 摘要 ( 13 )   A series of CuO/Ce1-xZrxO2 catalysts (x=0.2.0.4.0.6 and 0.8) are applied to elaborate the effect of the Zr/Ce ratio on the catalytic performance of CO2 hydrogenation to CH3OH.The best catalytic performance is achieved with CuO/Ce0.4Zr0.6O2.exhibiting XCO2=13.2% and YCH3OH=9.47% (T=280℃.P=3 MPa).The formation of dispersed surface CuO species and larger number of oxygen vacancies are detected over CuO/Ce0.4Zr0.6O2 due to stronger interaction between CuO and Ce0.4Zr0.6O2.resulting in the superior activation ability for H2 and CO2 respectively.Additionally.the evidence is provided by in situ DRIFTS under the activity test pressure (3 MPa) that bi/m-HCOO* species are preferable for accumulating over ceria-rich (CuO/Ce0.6Zr0.4O2 and CuO/Ce0.8Zr0.2O2) catalysts while zirconia-rich (CuO/Ce0.4Zr0.6O2 and CuO/Ce0.2Zr0.8O2) catalysts are benefit to encourage the transformation of bi/m-HCOO* species to CH3OH.The abundant population and high activity of intermediate species over CuO/Ce0.4Zr0.6O2 give a strong positive effect on the catalytic performance.

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A flexible CNT@nickel silicate composite film for high-performance sodium storage Ziyue Zhou, Wenping Si, Pengyi Lu, Wenlei Guo, Lei Wang, Tao Zhang,feng Hou, Ji Liang 2020, 47(8): 29-37.  DOI: 10.1016/j.jechem.2019.11.016 摘要 ( 10 )   Due to the sufficient ion diffusion channels provided by the large interlayer spacing.layered silicates are widely considered as potential anode materials for lithium ion and sodium ion batteries.However.due to the poor electronic conductivity.the application of layered silicates for electrochemical energy storage has been greatly limited.Carbon nanotube (CNT) film has excellent electrical conductivity and a unique interconnected network.making it an ideal matrix for composite electrochemical material.We herein report a CNT@nickel silicate composite film (CNT@NiSiO) fabricated by a SiO2-mediated hydrothermal conversion process.for sodium storage with excellent electrochemical properties.The obtained composite possesses a cladding structure with homogeneous nanosheets as the outermost and CNT film as the inner network matrix.providing abundant ion diffusion channels.high electronic conductivity.and good mechanical flexibility.Due to these merits.this material possesses an excellent electrochemical performance for sodium storage.including a high specific capacity up to 390 mAh g-1 at 50 mA g-1.good rate performance up to 205 mAh g-1 at 500 mA g-1.and excellent cycling stability.On this basis.this work would bring a promising material for various energy storage devices and other emerging applications.

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Bifunctional Li6CoO4 serving as prelithiation reagent and pseudocapacitive electrode for lithium ion capacitors Yuntao Guo, Xinhai Li, Zhixing Wang, Huajun Guo, Jiexi Wang 2020, 47(8): 38-45.  DOI: 10.1016/j.jechem.2019.11.003 摘要 ( 8 )   Lithium ion capacitors (LICs) have been widely used as energy storage devices due to their high energy density and high power density.For LICs.pre-lithiation of negative electrode is necessary.In this work.we employ a bifunctional Li6CoO4 (LCO) as cathodic pre-lithiation reagent to improve the electrochemical performance of LICs.The synthesized LCO exhibited high first charge specific capacity of 721 mAh g-1 and extremely low initial coulombic efficiency of 3.19%.providing sufficient Li+ for the pre-lithiation of negative electrode in the first charge.Simultaneously.Li6-xCoOy is generated from LCO during the first charge process.which exhibits pseudocapacitive property and contributes to capacity in form of surface capacitance during subsequent cycles.increasing the capacity of capacitive positive electrode.With the appropriate amounts of addition to the positive side in LICs.this bifunctional prelithiation reagent LCO shows significantly improved the electrochemical performance with the energy density of 78.5 Wh kg-1 after 300 cycles between 2.0 and 4.2 V at 250 mA g-1.

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Silicon prepared by electro-reduction in molten salts as new energy materials Tingting Jiang, Xinyi Xu, George Z.Chen 2020, 47(8): 46-61.  DOI: 10.1016/j.jechem.2019.11.005 摘要 ( 28 )   Silicon has a large impact on the energy supply and economy in the modern world.In industry.high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further refined by a modified Siemens method.This process suffers from the disadvantages of high cost and contaminant release and emission.As an alternative.the molten salt electrolysis approach.particularly the FFC Cambridge Process (FFC:Fray-Farthing-Chen).could realize high purity silicon products with morphology-controllable nanostructures at low or mild temperatures (generally 650-900℃).In this article.we review the development.reaction mechanisms.and electrolysis conditions of silicon production by the FFC Cambridge Process.Applications of the silicon products from electrolysis in molten salts are also discussed in terms of energy applications.including using them as the photovoltaic element in solar cells and as the charge storage phase in the negative electrode (negatrode) of lithium ion batteries.

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Stabilizing the MAPbI3 perovksite via the in-situ formed lead sulfide layer for efficient and robust solar cells Lujia Xie, Taiyang Zhang, Yixin Zhao 2020, 47(8): 62-65.  DOI: 10.1016/j.jechem.2019.11.023 摘要 ( 13 )   Surface passivation via post-treatment with organic reagents is a popular strategy to improve the stability and efficiency of perovskite solar cell.However.organic passivation still suffers from the weak bonding between organic chemicals and perovskite layers.Here we reported a facile inorganic layer passivating method containing strong Pb-S bonding by using ammonium sulfide treatment.A compact PbSx layer was in-situ formed on the top surface of the perovskite film.which could passivate and protect the perovskite surface to enhance the performance and stability.Our novel inorganic passivation layer strategy demonstrates great potential for the development of high efficiency hybrid and robust perovskite optoelectronics.

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MoO2 nanoparticles/carbon textiles cathode for high performance flexible Li-O2 battery Jia Liu,dan Li, Ying Wang, Siqi Zhang, Ziye Kang, Haiming Xie, Liqun Sun 2020, 47(8): 66-71.  DOI: 10.1016/j.jechem.2019.12.001 摘要 ( 10 )   Conventional Li-O2 battery is hardly considered as a next-generation flexible electronics thus far.since it is inflexible.bulk.and limited by the absence of the adjustable cell configuration.Here.we report a binder-free and flexible electrode of x wt% MoO2 NPs/CTs (x=6.16.and 28).A cell with 16 wt% MoO2 NPs/CTs displays a good cyclability over 240 cycles with a low overpotential of 0.33 V on the 1st cycle at a constant current density of 0.2 mA cm-2.a considerable rate performance.a superior reversibility associated with the desired formation and degradation of Li2O2.and a high electrochemical stability even under stringent bending and twisting conditions.Our work represents a promising progress in the material development and architecture design of O2 electrode for flexible Li-O2 batteries.

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Impact of evolution of cathode electrolyte interface of Li(Ni0.8Co0.1Mn0.1)O2 on electrochemical performance during high voltage cycling process Wei Wang, Qin Yang, Kun Qian,baohua Li 2020, 47(8): 72-78.  DOI: 10.1016/j.jechem.2019.10.027 摘要 ( 9 )   In this work.the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 (NCM811) has been investigated after cycling with various upper cutoff voltages.Noteworthily.electrochemical impedance of NCM811 declined with the increasing cycle number to high voltages.It was found that the decline of charge transfer impedance could be related to the structural and compositional change of cathode electrolyte interphase (CEI) of NCM811 when charging to high voltages.based on the characterization of electrochemical impedance spectroscopy (EIS).X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM).The corresponding mechanism has also been proposed in this study.Specifically.due to the increasing roughness of cathode surface.the bottom of CEI film and cubic phase on cathode surface form a transition region mainly at high voltages.leading to the nonobvious boundary.This newly formed transition region at high voltages could promote the Li ion diffusion from electrolyte to cathode.then reducing charge transfer impedance.Additionally.the decrease of LiF on the surface of the cathode could also make a contribution to lower the interface impedance.This study delivers a different evolution of CEI on NCM811.and the impact of CEI evolution on electrochemical performance when charging to a high voltage.

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In-situ growth of ZnS/FeS heterojunctions on biomass-derived porous carbon for efficient oxygen reduction reaction Rong Jiang, Xin Chen, Jinxia Deng, Tianyu Wang, Kang Wang, Yanli Chen, Jianzhuang Jiang 2020, 47(8): 79-85.  DOI: 10.1016/j.jechem.2019.11.028 摘要 ( 15 )   It is an urgent task to develop highly efficient non-noble metal electrocatalysts in the direction of ORR.but still a huge and long-term challenge.Herein.an efficient one-step pyrolysis of Sichuan pepper powder.2,2-bipyridine.FeCl3.NaSCN.and ZnCl2 at 900℃ provides the FeS/ZnS@N,S-C-900 hybrid catalyst.Transmission electron microscopy (TEM) images and Mott-Schottky curves clearly reveal the in-situ constructed abundant FeS/ZnS-based p-n junctions dispersed on the biomass-derived porous carbon surface of FeS/ZnS@N,S-C-900.The as-prepared FeS/ZnS@N,S-C-900 hybrid exhibits superior ORR performance in comparison with Pt/C in 0.1 M KOH with high onset (Eonset) and half-wave potentials (E1/2) of 1.00 and 0.880 V vs.RHE.large limiting current density (JL) of 5.60 mA cm-2.and robust durability and methanol tolerance.Impressively.upon the light irradiation.FeS/ZnS@N,S-C-900 produces a photocurrent as high as ca.0.3 μA cm-2.resulting in further improvement over Eonset.E1/2.and JL of FeS/ZnS@N,S-C-900 to 1.10 V vs.RHE.0.885 V vs.RHE.and 6.02 mA cm-2.Experiment in combination with theoretical calculations demonstrate the significant effect of FeS/ZnS heterojunction on the enhanced ORR catalytic activity of FeS/ZnS@N,S-C-900.This work is useful for the development of advanced heterojunction-based ORR catalysts for various energy conversion devices.

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Recent advances in nanomaterials for high-performance Li-S batteries James E.Knoop, Seongki Ahn 2020, 47(8): 86-106.  DOI: 10.1016/j.jechem.2019.11.018 摘要 ( 16 )   This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries.Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance.low environmental impact.low cost.high gravimetric (2600 W h kg-1) and volumetric (2800 W h L-1) energy densities.assuming complete conversion of sulfur to lithium sulfide (Li2S) upon lithiation.However.lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides (Li2Sn.n=3-8).low electrical conductivity.and low loading density of sulfur.These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur.To overcome these issues.strategies have been pursued using nanotechnology applied to porous carbon nanocomposites.hollow one-dimensional carbon nanomaterials.graphene nanocomposites.and three-dimensional carbon nanostructured matrices.This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium-sulfur batteries.Furthermore.we highlight perspective research directions for commercialization of lithium-sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.

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Room-temperature sputtered electrocatalyst WSe2 nanomaterials for hydrogen evolution reaction Jae Hyeon Nam, Myeong Je Jang, Hye Yeon Jang, Woojin Park, Xiaolei Wang, Sung Mook Choi,byungjin Cho 2020, 47(8): 107-111.  DOI: 10.1016/j.jechem.2019.11.027 摘要 ( 17 )   The low-temperature physical vapor deposition process of atomically thin two-dimensional transition metal dichalcogenide (2D TMD) has been gaining attention owing to the cost-effective production of diverse electrochemical catalysts for hydrogen evolution reaction (HER) applications.We.herein.propose a simple route toward the cost-effective physical vapor deposition process of 2D WSe2 layered nanofilms as HER electrochemical catalysts using RF magnetron sputtering at room temperature (<27℃).By controlling the variable sputtering parameters.such as RF power and deposition time.the loading amount and electrochemical surface area (ECSA) of WSe2 films deposited on carbon paper can be carefully determined.The surface of the sputtered WSe2 films are partially oxidized.which may cause spherical-shaped particles.Regardless of the loading amount of WSe2.Tafel slopes of WSe2 electrodes in the HER test are narrowly distributed to be~120-138 mV dec-1.which indicates the excellent reproducibility of intrinsic catalytic activity.By considering the trade-off between the loading amount and ECSA.the best HER performance is clearly observed in the 200W-15min sample with an overpotential of 220 mV at a current density of 10 mA cm-2.Such a simple sputtering method at low temperature can be easily expanded to other 2D TMD electrochemical catalysts.promising potentially practical electrocatalysts.

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Adjacent acid sites cooperatively catalyze fructose to 5-hydroxymethylfurfural in a new,facile pathway Xia Yu, Yueying Chu, Lei Zhang, Hui Shi, Mingjiang Xie, Luming Peng, Xuefeng Guo, Wei Li, Nianhua Xue, Weiping Ding 2020, 47(8): 112-117.  DOI: 10.1016/j.jechem.2019.11.020 摘要 ( 8 )   To study the effect of adjacent hydroxyl to the active sites.several acid catalysts.i.e.substituted benzoic acids with adjacent carboxyl are employed in the fructose dehydration to 5-hydroxymethylfurfural (HMF).Experimental results reveal that Brønsted acid sites with adjacent carboxyl present higher catalytic ability than isolated ones.Computational results suggest that the adjacent sites lead to co-interaction on fructose.corresponding more stable transition state and faster HMF formation rate.Based on the enhancement from the adjacent sites.a novel ordered mesoporous carbon (OMC) full of carboxyls in surface is prepared and turns out to be an effective solid catalyst for HMF production from fructose derived from biomass.

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Effects of K and Mn promoters over Fe2O3 on Fischer-Tropsch synthesis Teng Lv, Wei Weng, Jing Zhou,dong Gu, Wei Xiao 2020, 47(8): 118-127.  DOI: 10.1016/j.jechem.2019.12.003 摘要 ( 6 )   Structural and compositional design of core-shell structure is an effective strategy towards enhanced catalysis.Herein.amorphous MnO2 nanosheets and K+-intercalated layered MnO2 nanosheets are controllably assembled over Fe2O3 spindles.in which the MnO2 nanosheets are perpendicularly anchored to the surface of Fe2O3.Such a core shell structure contributes to a high specific surface area and abundant pore channels on the surface of catalysts.In addition.the existence of K+ provides large numbers of basic sites and restrains the formation of unpleasant (Fe1-xMnx)3O4.Benefiting from the merits in structure and composition.CO adsorption is enhanced and remaining time of intermediates is prolonged on the surfaces of catalysts during the Fischer-Tropsch synthesis (FTS).facilitating to the formation of active iron carbides and C-C coupling reactions.Resultantly.the Fe2O3@K+-MnO2 shows both a high CO conversion of 82.3% and a high C5+ selectivity of 73.1%.The present study provides structural and compositional rationales on design high-performance catalysts towards FTS.

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The origin of sulfuryl-containing components in SEI from sulfate additives for stable cycling of ultrathin lithium metal anodes Jin-Xiu Chen, Xue-Qiang Zhang,bo-Quan Li, Xin-Meng Wang, Peng Shi, Wancheng Zhu, Aibing Chen, Zhehui Jin, Rong Xiang, Jia-Qi Huang, Qiang Zhang 2020, 47(8): 128-131.  DOI: 10.1016/j.jechem.2019.11.024 摘要 ( 24 )

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Crucial role of charge transporting layers on ion migration in perovskite solar cells Abasi Abudulimu, Lang Liu, Guilin Liu, Nijiati Aimaiti,bohuslav Rezek, Qi Chen 2020, 47(8): 132-137.  DOI: 10.1016/j.jechem.2019.12.002 摘要 ( 20 )   The device preconditioning dependent hysteresis and the consequential performance degradation hinder the actual performance and stability of the perovskite solar cells.Ion migration and charge trapping in the perovskite with large contribution from grain boundaries are the most common interpretations for the hysteresis.Yet.the high performing devices often include intermediate hole and electron transporting layers.which can further complicate the dynamical process in the device.Here.by using Kelvin Probe Force Microscopy and Confocal Photoluminescence Microscopy.we elucidate the impact of chargetransporting layers and excess MAI on the spatial and temporal variations of the photovoltage on the MAPbI3-based solar cells.By studying the devices layer by layer.we found that the light-induced ion migration occurs predominantly in the presence of an imbalanced charge extraction in the solar cells.and the charge transporting layers play crucial role in suppressing it.Careful selection and processing of the electron and hole-transporting materials are thus essential for making perovskite solar cells free from the ion migration effect.

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Rapid synthesis of highly active Pt/C catalysts with various metal loadings from single batch platinum colloid Yuxin Li, Xiang Zhu, Yawen Chen, Shiqiao Zhang, Jia Li, Jianguo Liu 2020, 47(8): 138-145.  DOI: 10.1016/j.jechem.2019.12.004 摘要 ( 45 )   A series of Pt/C catalysts for proton exchange membrane fuel cells (PEMFCs) with various metal loadings is synthesized by a microwave-assisted polyol process via mixing an extremely stable platinum colloid (> 3 months' shelf life) from single batch preparation with activated carbon ethylene glycol suspension.21 wt%.42 wt% and 61 wt% Pt loadings are employed to showcase the advantages of the improved polyol process.The ultraviolet (UV)-visible spectra and ζ -potential measurements are conducted to monitor the wet chemistry process during catalyst preparation.The powder X-ray diffraction (XRD).transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) characterizations are carried out on catalysts.The catalyst activities are investigated using electrochemical and single cell tests.The stability of Pt nanoparticle colloid is explored by ORR.cyclic voltammetry (CV) and ζ -potential measurements.The TEM results show the Pt particle sizes of the colloid.and the sizes of the 21 wt%.42 wt% and 61 wt% Pt/C samples are 2.1-3.9 nm.Because of the high Pt dispersion.the Pt/C catalysts exhibit superior electroactivity toward ORR.In addition.four 61 wt% Pt/C catalysts made from the Pt colloid with 0-3 months' shelf life show almost the same performance.which exhibits superior stability of the Pt colloid system without surfactant protection.

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Ni-Co bimetallic coordination effect for long lifetime rechargeable Zn-air battery Mengfei Qiao, Ying Wang, Thomas Wågberg, Xamxikamar Mamat, Xun Hu, Guoan Zou, Guangzhi Hu 2020, 47(8): 146-154.  DOI: 10.1016/j.jechem.2019.12.005 摘要 ( 13 )   The development of bifunctional oxygen electrocatalysts with high efficiency.high stability.and low cost is of great significance to the industrialization of rechargeable Zn-air batteries.A widely accepted view is that the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) follow different catalytic mechanisms.and accordingly they need different active sites for catalysis.Transition metal elements have admirable electronic acceptance ability for coordinating with reactants.and this can weaken the bond energy between reactants.thus promoting the ORR or OER reactions.Herein.the ORR and OER activities of different transition metal supported nitrogen-doped carbon nanotubes were systematically studied and compared.The optimal catalyst for synchronous ORR and OER was obtained by pyrolyzing melamine.cobalt nitrate.and nickel nitrate on carbon nanotubes.called cobalt-nickel supported nitrogenmixed carbon nanotubes (CoNi-NCNT).which were equipped with two types of high-performance active sites-the Co/Ni-N-C structure for the ORR and CoNi alloy particles for the OER-simultaneously.Remarkably.the optimized CoNi-NCNT exhibited a satisfactory bifunctional catalytic activity for both the ORR and OER.The value of the oxygen electrode activity parameter.△E.of CoNi-NCNT was 0.81 V.which surpasses that of catalysts Pt/C and Ir/C.and most of the non-precious metal-based bifunctional electrocatalysts reported in previous literatures.Furthermore.a specially assembled rechargeable Zn-air cell with CoNi-NCNT loaded carbon paper as an air cathode was used to evaluate the practicability.As a result.a superior specific capacity of 744.3 mAh/gZn.a peak power density of 88 mW/cm2.and an excellent rechargeable cycling stability were observed.and these endow the CoNi-NCNT with promising prospects for practical application.

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Dynamic carbon surface chemistry: Revealing the role of carbon in electrolytic water oxidation Yuxiao Ding, Qingqing Gu, Alexander Klyushin, Xing Huang, Sakeb H.Choudhury, Ioannis Spanos,feihong Song, Rik Mom, Pascal Düngen, Anna K.Mechler, Robert Schlögl, Saskia Heumann 2020, 47(8): 155-159.  DOI: 10.1016/j.jechem.2019.12.006 摘要 ( 8 )   Carbon materials have been widely used as electrodes.but the mechanistic roles are still not clear due to the complexity of the carbon surface chemistry.Herein we clarify that intrinsic material properties of carbon have to be activated by extrinsic factors.Pure carbon has no catalytic activity when used as electrode for electrocatalytic water oxidation.The evolution of oxygen functional groups on the carbon surface with increasing potential and the subsequent formation of real active sites with iron impurities from the electrolyte have been confirmed.These in-situ formed active sites protect the carbon from deep oxidation.This unprecedented finding not only provides insight into the dynamic evolution of carbon electrode surface chemistry and raises awareness of the need for detailed surface analysis under operando conditions.but also suggests a direction for the development of scalable and high-performance carbonbased electrode systems for various electrochemical applications.

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2D-layered Sn/Ge anodes for lithium-ion batteries with high capacity and ultra-fast Li ion diffusivity Xiyu Cao, Yanchen Fan, Jiale Qu, Tianshuai Wang,dominik Legut, Qianfan Zhang 2020, 47(8): 160-165.  DOI: 10.1016/j.jechem.2019.11.025 摘要 ( 26 )

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Electrochemical oxygen evolution reaction efficiently boosted by selective fluoridation of FeNi3 alloy/oxide hybrid Meng Zha,chengang Pei, Quan Wang, Guangzhi Hu, Ligang Feng 2020, 47(8): 166-171.  DOI: 10.1016/j.jechem.2019.12.008 摘要 ( 15 )   Performance boosting of hybrid metal oxide and metal alloy catalyst is crucial to the water electrolysis for hydrogen generation.Herein.a novel concept of selective fluoridation of metal alloy/oxide hybrid is proposed to boost their catalytic performance for the oxygen evolution reaction (OER).A well-recognized OER catalyst system of FeNi3 alloy/oxide embedded in nitrogen-doped porous nanofibers (FeNiO/NCF) is employed as a proof of concept.and it is selectively fluoridated by transforming the metal oxide to metal fluoride (FeNiF/NCF).The crystal structure and surface chemical state transformation are well supported by the spectroscopic analysis and the improved electrochemical performance for OER can be well correlated to the phase and structure change.Specifically.FeNiF/NCF can drive the benchmark current density of 10 mA cm-2 at 260 mV with a Tafel slope of 67 mV dec-1.about 70 mV less than that of FeNiO/NCF.Increased catalytic kinetics.rapid charge transfer ability.high catalytic efficiency and stability are also probed by electrochemical analysis.The high surface area and roughness are found mainly generated via the high-temperature annealing for the metal alloy/metal oxide formation.and the low-temperature fluoridation process intrinsically contributes to the active structure formation.It is an efficient and universal approach to increase the catalytic performance of metal alloy/oxide for energy-relevant catalytic reactions.

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3D hierarchically porous NiO/Graphene hybrid paper anode for long-life and high rate cycling flexible Li-ion batteries Ju Fu, Wenbin Kang, Xiaodong Guo, Hao Wen, Tianbiao Zeng, Ruoxin Yuan,chuhong Zhang 2020, 47(8): 172-179.  DOI: 10.1016/j.jechem.2019.11.022 摘要 ( 7 )   With the rapid emergence of wearable devices.flexible lithium-ion batteries (LIBs) are much more needed than ever.Free-standing graphene-based composite paper electrodes with various active materials have appealed wide applications in flexible LIBs.However.due to the prone-to-restacking feature of graphene layers.a long cycle life at high current densities is rather difficult to be achieved.Herein.a unique threedimensional (3D) hierarchically porous NiO micro-flowers/graphene paper (fNiO/GP) electrode is successfully fabricated.The resulting fNiO/GP electrode shows superior long-term cycling stability at high rates (e.g..storage capacity of 359 mAh/g after 600 cycles at a high current density of 1 A/g).The facile 3D porous structure combines both the advantages of the graphene that is highly conductive and flexible to ensure rapid electrons/ions transfer and buffer the volume expansion of NiO during charge/discharge.and of the micro-sized NiO flowers that induces hierarchical between-layer pores ranging from nanomicro meters to promote the penetration of the electrolyte and prevent the re-stacking of graphene layers.Such structural design will inspire future manufacture of a wide range of active materials/graphene composite electrodes for high performance flexible LIBs.

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Photophysics,morphology and device performances correlation on non-fullerene acceptor based binary and ternary solar cells Guanqing Zhou, Hong Ding, Lei Zhu,chaoqun Qiu, Ming Zhang, Tianyu Hao, Wei Feng, Yongming Zhang, Haiming Zhu,feng Liu 2020, 47(8): 180-187.  DOI: 10.1016/j.jechem.2019.12.007 摘要 ( 15 )   Non-fullerene acceptor (NFA) based organic solar cells (OSCs) are of high efficiency and low energy loss and low recombination features.which is owing to the advantage of non-fullerene acceptors.The photophysics investigation of non-fullerene solar cells.in comparing to fullerene based analogue as well as mixed acceptor ternary blends could help to understand the working mechanism of NFA functioning mechanism.We choose PBDB-T donor.the fullerene derivative PC71BM acceptor.and the non-fullerene acceptor ITIC as the model system.to construct binary and ternary solar cells.which then subject to ultrafast spectroscopy investigation.The charge transfer pathway in binary and ternary blends is revealed.And it is seen that ITIC leads to a faster exciton separation and exciton diffusion.ITIC in blends suppresses the geminate recombination and shows smaller amount of charge transfer states.which is beneficial for the device performance.And the addition of ITIC enhances the crystallinity for both donor and acceptor leads to a morphology change of forming bicontinuous crystalline networks and phase separation.In a consequence.fill factor and JSC.increase dramatically for the related OSC.

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Well-ordered layered LiNi0.8Co0.1Mn0.1O2 submicron sphere with fast electrochemical kinetics for cathodic lithium storage Jianing Liang, Yun Lu, Jie Wang, Xupo Liu, Ke Chen, Weihao Ji, Ye Zhu,deli Wang 2020, 47(8): 188-195.  DOI: 10.1016/j.jechem.2019.12.009 摘要 ( 12 )   Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However.nickel-rich layered oxides also have exposed several defects for commercial application.such as uncontrollable ordered layered structure.which leads to higher energy barrier for Li+ diffusion.In addition.suffering from structural mutability.the bulk nickelrich cathode materials likely trigger overall volumetric variation and intergranular cracks.thus obstructing the lithium ion diffusion path and shortening the service life of the whole device.Herein.we report wellordered layered LiNi0.8Co0.1Mn0.1O2 submicron spheroidal particles via an optimized co-precipitation and investigated as LIBs cathodes for high-performance lithium storage.The as-fabricated LiNi0.8Co0.1Mn0.1O2 delivers high initial capacity of 228 mAh g-1.remarkable energy density of 866 Wh kg-1.rapid Li ion diffusion coefficient (10-9 cm2 s-1) and low voltage decay.The remarkable electrochemical performance should be ascribed to the well-ordered layered structure and uniform submicron spheroidal particles.which enhance the structural stability and ameliorate strain relaxation via reducing the parcel size and shortening Li-ion diffusion distance.This work anticipatorily provides an inspiration to better design particle morphology for structural stability and rate capability in electrochemistry energy storage devices.

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Non-conjugated polymers as thickness-insensitive electron transport materials in high-performance inverted organic solar cells Zhiquan Zhang, Zheling Zhang, Yufu Yu,bin Zhao, Sheng Li, Jian Zhang, Songting Tan 2020, 47(8): 196-202.  DOI: 10.1016/j.jechem.2019.12.011 摘要 ( 26 )   Two non-conjugated polymers PEIE-DBO and PEIE-DCO.prepared by quaternization of polyethyleneimine ethoxylate by 1,8-dibromooctane and 1,8-dichlorooctane respectively.are developed as electron transport layer (ETL) in high-performance inverted organic solar cells (OSCs).and the effects of halide ions on polymeric photoelectric performance are fully investigated.PEIE-DBO possesses higher electron mobility (3.68×10-4 cm2 V-1 s-1).higher conductivity and more efficient exciton dissociation and electron extraction.attributed to its lower work function (3.94 eV) than that of PEIE-DCO.which results in better photovoltaic performance in OSCs.The inverted OSCs with PTB7-Th:PC71BM as photoactive layer and PEIE-DBO as ETL exhibit higher PCE of 10.52%.9.45% and 9.09% at the thickness of 9.35 and 50 nm.respectively.To our knowledge.PEIE-DBO possesses the best thickness-insensitive performance in polymeric ETLs of inverted fullerene-based OSCs.Furthermore.PEIE-DBO was used to fabricate the inverted non-fullerene OSCs (PM6:Y6) and obtained a high PCE of 15.74%.which indicates that PEIE-DBO is effective both in fullerene-based OSCs and fullerene-free OSCs.

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Highly safe and ionothermal synthesis of Ti3C2 MXene with expanded interlayer spacing for enhanced lithium storage Junbiao Wu, Yu Wang, Yaopeng Zhang, Hao Meng, Yan Xu, Yide Han, Zhuopeng Wang, Yanfeng Dong, Xia Zhang 2020, 47(8): 203-209.  DOI: 10.1016/j.jechem.2019.11.029 摘要 ( 18 )   MXene is a rising star of two-dimensional (2D) materials for energy relative applications.however.the traditional synthesis of MXene etched by hazard HF acid or LiF+HCl mixed solution is highly dangerous with the risk of splashing or pouring liquid solutions.In this work.we developed a water-free ionothermal synthesis of 2D Ti3C2 MXene via etching pristine Ti3AlC2 MAX in low-cost choline chloride and oxalic acid based deep eutectic solvents (DES) with the presence of NH4F.thus it was highly safe and convenient to operate solid precursor and product materials at room temperature.Benefited from the low vapor pressure and solvating properties of DES.the prepared Ti3C2 (denoted as DES-Ti3C2) possessed a high purity up to 98% compared with 95% for HF etched Ti3C2 (denoted as HF-Ti3C2).Notably.an expanded interlayer spacing of 1.35 nm could be achieved due to the intercalation of choline cations in DES-Ti3C2.larger than that of HF-Ti3C2 (0.98 nm).As a result.the DES-Ti3C2 anodes exhibited enhanced lithium storage performance.such as high reversible capacity of 208 mAh g-1 at 0.5 A g-1.and long cycle life over 400 times.outperforming most reported pure MXene anodes.The ionothermal synthesis of MXene developed here may pave a new way to safely prepare other MXene for various energy relating applications.

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Optimizing the micropore-to-mesopore ratio of carbon-fiber-cloth creates record-high specific capacitance Ying Zheng, Ting Deng, Wei Zhang, Weitao Zheng 2020, 47(8): 210-216.  DOI: 10.1016/j.jechem.2019.12.014 摘要 ( 13 )   The application of commercial carbon fiber cloth (CFC) in energy storage equipment is limited by its low specific capacitance and energy density.By a simple one-step activation treatment.the specific surface area of CFCs with porous structure can be increased considerably from 3.9 up to 875 m2/g and the electrochemical properties of CFCs can be improved by three orders of magnitude (1324 mF/cm2).Moreover.the hydrophobicity of CFCs can be transformed into superhydrophilicity.However.the electrochemical performance of CFCs does not show a positive correlation with specific surface area but have a strong relationship with the hierarchical pore distribution forged by the annealing treatment.Only moderate micropore and mesoporous ratio enables optimizing the electrochemical performance of CFCs.

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Perspective on the critical role of interface for advanced batteries Chong Yan, Hong Yuan, Ho Seok Park, Jia-Qi Huang 2020, 47(8): 217-220.  DOI: 10.1016/j.jechem.2019.09.034 摘要 ( 61 )

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Layer-by-layer growth of ZIF-8 on electrospun carbon nanofiber membranes for high-performance supercapacistor electrode Kan Mi, Lanlan Song, Hongjiao Nie, Tao Liu, Xianfeng Li 2020, 47(8): 221-224.  DOI: 10.1016/j.jechem.2019.10.028 摘要 ( 75 )   Industrial propane dehydrogenation (PDH) catalysts generally suffer from low catalytic stability due to the coke formation onto the catalyst surface to cover the active sites.The exploitation of an efficient catalyst with both high catalytic selectivity and long-term stability toward PDH is of great importance but challenging to make.Herein CrOx supported on high-silica HZSM-5 with a SiO2/Al2O3 ratio of 260 (Cr/Z-5(260) is synthesized by a simple wet impregnation method.which exhibits high catalytic activity.good selectivity and excellent stability for PDH.At a weight hourly space velocity (WHSV) of 0.59 h-1.a propylene formation rate of 4.1 mmol gcat-1 h-1 (~32.6% propane conversion and~94.2% propylene selectivity) can be maintained over the 5%Cr/Z-5(260) catalyst after 50 h time on stream.which is much better than commercial Cr/Al2O3 (Catofin process.catalyst life is several hours) at the same reaction conditions.With increasing the WHSV to 5.9 h-1.a high propylene formation rate of 27.9 mmol gcat-1 h-1 can be obtained over the 5%Cr/Z-5(260) catalyst after 50 h time on stream.demonstrating a very promising PDH catalyst.Characterization results and Na+ doping experiments reveal that the Cr species combined with Brønsted acid sites in Cr/HZSM-5 catalysts are responsible for the high catalytic performance.In particular.the Brønsted acid sites in HZSM-5 zeolite could increase the propane adsorption and enhance the C-H bond activation.Furthermore.the high surface area and well-defined pores of HZSM-5 zeolite can provide a special environment for the dispersion and stabilization of Cr species.thus guaranteeing high catalytic activity and stability.

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CrOx supported on high-silica HZSM-5 for propane dehydrogenation Zhong-Pan Hu, Yansu Wang,dandan Yang, Zhong-Yong Yuan 2020, 47(8): 225-233.  DOI: 10.1016/j.jechem.2019.12.010 摘要 ( 5 )   The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation.which highly relies on electrocatalytic performance of electrocatalysts.In this work.high-quality platinum (Pt) nanocubes (Pt-NCs) with 4.5 nm size are achieved by facile hydrothermal synthesis.The physical morphology and structure of Pt-NCs are exhaustively characterized.revealing that Pt-NCs with special {100} facets have excellent uniformity.good dispersity and high crystallinity.Meanwhile.the electrocatalytic performance of Pt-NCs for ammonia electrolysis are carefully investigated in alkaline solutions.which display outstanding electroactivity and stability for both ammonia electrooxidation reaction (AEOR) and hydrogen evolution reaction (HER) in KOH solution.Furthermore.a symmetric Pt-NCs||Pt-NCs ammonia electrolyzer based on bifunctional Pt-NCs electrocatalyst is constructed.which only requires 0.68 V electrolysis voltage for hydrogen generation.Additionally.the symmetric Pt-NCs||Pt-NCs ammonia electrolyzer has excellent reversible switch capability for AEOR at anode and HER at cathode.showing outstanding alternating operation ability for ammonia electrolysis.

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Hydrogen generation from ammonia electrolysis on bifunctional platinum nanocubes electrocatalysts Hui-Ying Sun, Guang-Rui Xu,fu-Min Li, Qing-Ling Hong, Pu-Jun Jin, Pei Chen, Yu Chen 2020, 47(8): 234-240.  DOI: 10.1016/j.jechem.2020.01.035 摘要 ( 53 )   Lithium-sulfur batteries (LSBs) hold great potential for large-scale electrochemical energy storage applications.Currently.the shuttle of soluble lithium polysulfide (LiPSs) intermediates with sluggish conversion kinetics and random deposition of Li2S have severely degraded the capacity.rate and cycling performances of LSBs.preventing their practical applications.In this work.ultrathin MoSe2 nanosheets with active edge sites were successfully grown on both internal and external surfaces of hollow carbon spheres with mesoporous walls (MCHS).The resulting MoSe2@MCHS composite acted as a novel functional reservoir for LiPSs with high chemical affinity and effectively mediated their fast redox conversion during charge/discharge as elucidated by experimental observations and first-principles density functional theory (DFT) calculations.The as-fabricated Li-S cells delivered high capacity.superior rate and excellent cyclability.The current work presents new insights on the delicate design and fabrication of novel functional composite electrode materials for rechargeable batteries with emerging applications.

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MoSe2 nanosheets as a functional host for lithium-sulfur batteries Lishun Meng, Yuan Yao, Jing Liu, Zhao Wang,dong Qian, Liuchun Zheng,bao-Lian Su, Hong-En Wang 2020, 47(8): 241-247.  DOI: 10.1016/j.jechem.2020.02.003 摘要 ( 12 )   Molybdenum phosphide (MoP) catalyst has been widely applied in hydrogenation reactions.while the preparation of unsupported MoP catalysts with ultra-small size and large specific surface area (SBET) is still challenging.Herein.we have provided a facile method for preparing a series of MoP-x (x=P/Mo ratios ranging from 1 to 5) catalysts by pyrolyzing phytic acid (PA)-derived Mo complexes in a H2 atmosphere.The physicochemical properties and the catalytic activity of MoP catalysts were investigated.The results showed that the obtained MoP-5 catalyst had the largest SBET and exhibited ultra-small nanoparticle diameter of 3.6 nm.which ascribed to the chelation of PA and the confinement of deposited products.As the content of PA increased.the synthetic mechanism of MoP was also affected.which led to the difference in the valence of surface Mo species.The characterization results further confirmed that Moδ+ sites in MoP catalysts are active sites for methanation reaction and its content on the surface of MoP-x catalysts determines the catalytic activity.

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Phytic acid-derived fabrication of ultra-small MoP nanoparticles for efficient CO methanation: Effects of P/Mo ratios Jun Zhao, Zijia Yin,baowei Wang, Zhenhua Li, Yan Xu, Xinbin Ma 2020, 47(8): 248-255.  DOI: 10.1016/j.jechem.2020.02.007 摘要 ( 12 )   Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries.However.the flammability of organic compounds brings in serious concern on battery safety.In addition to use flame-retarding electrolyte/electrolyte additives or battery separators.flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone.imparting the flame retardancy permanently.The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties.Moreover.two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca.120 mAh g-1 at a current rate of 2 C.The origin of the reversibility is investigated through density functional theory (DFT) calculations.These findings address the importance of molecular design for safer and more stable organic materials for batteries.

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Flame-retarding battery cathode materials based on reversible multi-electron redox chemistry of phenothiazine-based polymer Jing Lv, Jing Ye, Gaole Dai, Zhihui Niu, Yi Sun, Xiaohong Zhang, Yu Zhao 2020, 47(8): 256-262.  DOI: 10.1016/j.jechem.2020.02.017 摘要 ( 9 )   Developing the highly active.cost-effective.environmental-friendly.and ultra-stable nonprecious electrocatalysts for hydrogen evolution reaction (HER) is distinctly indispensable for the large-scale practical applications of hydrolytic hydrogen production.Herein.we report the synthesis of well-integrated electrode.NiV layered double hydroxide nanosheet array grown in-situ on porous nickel foam (abbreviated as in-NiV-LDH/NF) via the facile one-step hydrothermal route.Interestingly.the valence configuration of vanadium (V) sites in such NiV-LDH are well dominated by the innovative use of NF as the reducing regulator.achieving the reassembled in-NiV-LDH/NF with a high proportion of trivalent V ions (V3+).and then an enhanced intrinsic electrocatalytic HER activity.The HER testing results show that the in-NiV-LDH/NF drives the current densities of 10 and 100 mA cm-2 at extremely low overpotentials of 114 and 245 mV without iR-compensation respectively.even outperforms commercial 20 wt% Pt/C at the large current density of over 80 mA cm-2 in alkaline media.as well as gives robust catalytic durability of at least 100 h in both alkaline and neutral media.More importantly.this work provides a fresh perspective for designing bimetal (oxy) hydroxides electrocatalysts with efficient hydrogen generation.

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In-situ optimizing the valence configuration of vanadium sites in NiV-LDH nanosheet arrays for enhanced hydrogen evolution reaction Danyang He, Liyun Cao, Jianfeng Huang, Koji Kajiyoshi, Jianpeng Wu,changcong Wang, Qianqian Liu,dan Yang, Liangliang Feng 2020, 47(8): 263-271.  DOI: 10.1016/j.jechem.2020.02.010 摘要 ( 19 )   Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional.high-performance materials for the energy conversion and storage.Nonprecious metal catalysts.such as cobalt oxide.with superior activity and excellent stability to other catalysts are widely desired.Nevertheless.the performance of CoO nanoparticles as an electrode material were significantly limit for its inferior conductivity.dissolution.and high cohesion.Herein.we grow ultrafine cobalt monoxide to decorate the interlayer and surface of the Ti3C2Tx nanosheets via a hydrothermal method companied by calcination.The layered MXenes act as the underlying conductive substrate.which not only increase the electron transfer rate at the interface but also greatly improve the electrochemical properties of the nanosized CoO particles by restricting the aggregation of CoO.The resulting CoO/Ti3C2Tx nanomaterial is applied as oxygen electrode for lithium-oxygen battery and achieves more than 160 cycles and first cycle capacity of 16,220 mAh g-1 at 100 mA g-1.This work paves a promising avenue for constructing a bi-functional catalyst by coupling the active component of a transition metal oxide (TMO) with the MXene materials in lithium-oxygen battery.

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In situ decoration of nanosized metal oxide on highly conductive MXene nanosheets as efficient catalyst for Li-O2 battery Xingyu Li,caiying Wen, Huifeng Li, Genban Sun 2020, 47(8): 272-280.  DOI: 10.1016/j.jechem.2020.02.016 摘要 ( 6 )   The major challenge for realistic application of Li-S batteries lies in the great difficulty in breaking through the obstacles of the sluggish kinetics and polysulfides shuttle of the sulfur cathode at high sulfur loading for continuously high sulfur utilization during prolonged charge-discharge cycles.Here we demonstrate that large percentage of sulfur can be effectively incorporated within a three-dimensional (3D) nanofiber network of high quality graphene from chemical vapor deposition (CVD).through a simple ball-milling process.While high quality graphene network provided continuous and durable channels to enable efficient transport of lithium ions and electrons.the in-situ sulfur doping from the alloying effect of ball milling facilitated desirable affinity with entire sulfur species to prevent sulfur loss and highly active sites to propel sulfur redox reactions over cycling.This resulted in remarkable rate-performance and excellent cycling stability.together with large areal capacity at very high sulfur mass loading (Specific capacity over 666 mAh g-1 after 300 cycles at 0.5 C.and areal capacity above 5.2 mAh cm-2 at 0.2 C at sulfur loading of 8.0 mg cm-2 and electrolyte/sulfur (E/S) ratio of 8 μL mg-1;and high reversible areal capacities of 13.1 mAh cm-2 at a sulfur load of 15 mg cm-2 and E/S of 5 μL mg-1).

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In situ sulfur-doped graphene nanofiber network as efficient metal-free electrocatalyst for polysulfides redox reactions in lithium-sulfur batteries Shijie Zhang, Peng Zhang, Ruohan Hou,bin Li, Yongshang Zhang, Kangli Liu, Xilai Zhang, Guosheng Shao 2020, 47(8): 281-290.  DOI: 10.1016/j.jechem.2020.01.033 摘要 ( 14 )   Development of cost-effective and highly active oxygen evolution catalysts operating well in acidic media is a critical challenge in proton exchange membrane water electrolysis.Herein.we present a class of iridium-based 12L-perovskites (Ba4MIr3O12;M=Pr.Bi.Nb) as novel low-iridium electrocatalysts for oxygen evolution reaction under acidic conditions.These 12L-perovskites contain trinuclear face-shared IrO6 octahedral strings-unique subunits that are not found in the previously-reported iridium-based electrocatalysts.The catalytic activities of 12L-perovskites (Ba4MIr3O12) are found to be related to the location of O 2p-band center.which is influenced by the B-site nonprecious element (i.e..Pr.Bi or Nb).Our experimental results show that Ba4PrIr3O12 is the most active electrocatalyst among the materials we synthesize.and contains 55% less iridium than the benchmark catalyst IrO2.while exhibiting higher catalytic activity.In the presence of Ba4PrIr3O12.transient leaching process of Ba and Pr takes place during electrochemical process.contributing to the surface reconstruction of the pristine catalysts.Further experimental results reveal that the formation of under-coordinated IrOx-rich surface and easier generation of active intermediate IrV are mainly responsible for the good activity of Ba4PrIr3O12.

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Efficient acidic oxygen evolution reaction electrocatalyzed by iridium-based 12L-perovskites comprising trinuclear face-shared IrO6 octahedral strings Ruiqin Gao, Qi Zhang, Hui Chen, Xuefeng Chu, Guo-Dong Li, Xiaoxin Zou 2020, 47(8): 291-298.  DOI: 10.1016/j.jechem.2020.02.002 摘要 ( 21 )   Construction of oxygen evolution electrocatalysts with abundant oxygen defects and large specific surface areas can significantly improve the conversion efficiency of overall water splitting.Herein.we adopt a controlled method to prepare oxygen defect-rich double-layer hierarchical porous Co3O4 arrays on nickel foam (DL-Co3O4/NF) for water splitting.The unique array-like structure.crystallinity.porosity.and chemical states have been carefully investigated through SEM.TEM.XRD.BET.and XPS techniques.The designated DL-Co3O4/NF has oxygen defects of up to 67.7% and a large BET surface area (57.4 m2 g-1).Electrochemical studies show that the catalyst only requires an overpotential of 256 mV to reach 20 mA cm-2.as well as a small Tafel slope of 60.8 mV dec-1.which is far better than all control catalysts.Besides.the catalyst also demonstrates excellent overall water splitting performance in a two-electrode system and good long-term stability.far superior to most previously reported catalysts.Electrocatalytic mechanisms indicate that abundant oxygen vacancies provide more active sites and good conductivity.At the same time.the unique porous arrays facilitate electrolyte transport and gas emissions.thereby synergistically improving OER catalytic performance.

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Oxygen defect-rich double-layer hierarchical porous Co3O4 arrays as high-efficient oxygen evolution catalyst for overall water splitting Puxuan Yan, Meilin Huang,benzhi Wang, Zixia Wan, Mancai Qian, Hu Yan, Tayirjan Taylor Isimjan, Jianniao Tian, Xiulin Yang 2020, 47(8): 299-306.  DOI: 10.1016/j.jechem.2020.02.006 摘要 ( 17 )   Li7P3S11 solid electrolytes with high lithium-ion conductivity are promising candidates for use in all-solidstate lithium batteries.However.this electrolyte's poor interfacial compatibility with lithium electrodes causes unstable cyclability.In this study.in order to address this problem.(100-x)Li7P3S11-xLi2OHBr (x=0.2.5.10.20.30.40.and 50) electrolytes are prepared by a high energy ball-milling technique and heat-treatment process.The resulting (100-x)Li7P3S11-xLi2OHBr (x=2.5.10.20.30.40.and 50) electrolytes provide improved electrochemical performance with good cycling stability and a wide electrochemical window of up to 10 V (vs.Li/Li+).Moreover.these electrolytes have high ionic conductivity of 10-4-10-5 S/cm at room temperature.Particularly.the 90Li7P3S11-10Li2OHBr electrolyte displays the highest conductivity of 4.4×10-4 S/cm at room temperature as well as improved cyclability.Moreover.90Li7P3S11-10Li2OHBr shows decreased interfacial resistance between the solid electrolyte and cathode electrode.which was revealed by Electrochemical Impedance Spectroscopy (EIS) analysis.The initial discharge capacity of 90Li7P3S11-10Li2OHBr was found to be 135 mAh/g when used in a In|solid electrolyte|Li(Ni0.6Co0.2Mn0.2)O2 all-solid-state lithium battery (ASSLB).Thus.we can conclude the addition of Li2OHBr into the Li7P3S11 results in enhanced electrochemical properties.

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Synthesis and electrochemical performance of (100-x)Li7P3S11-xLi2OHBr composite solid electrolyte for all-solid-state lithium batteries Su-Yeon Jung, Rajesh Rajagopal, Kwang-Sun Ryu 2020, 47(8): 307-316.  DOI: 10.1016/j.jechem.2020.02.018 摘要 ( 13 )   One of the most primary challenges to achieve large-scale hydrogen generation from water electrolysis is the sluggish kinetics and noble metal dependence of cathodic hydrogen evolution reaction (HER).By considering the excellent water dissociation catalytic activity of Mo2C.abundant Pt/Mo2C interfaces were facilely engineered via galvanic replacement (gr) by using Mo/Mo2C nanosheets as self-sacrificed templates to alter the alkaline HER mechanism on Pt based catalyst.The rational designed interface-rich gr-Pt/Mo2C catalyst exhibited excellent activity with the overpotential to drive 10 mA/cm2 current density decreased by 18.5 mV compared with the commercial Pt/C catalyst.34.3 mV/dec Tafel slope confirms the Volmer-Tafel HER route on gr-Pt/Mo2C in alkaline condition.Platinum utilization is calculated to be improved by 9.7 times by considered the low Pt loading in the gr-Pt/Mo2C catalyst.With its satisfied stability.the scalable gr-Pt/Mo2C catalyst shows promising application potential in industrial electrolysis systems.

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Pt/Mo2C heteronanosheets for superior hydrogen evolution reaction Zhao Liu, Jing Li, Shiji Xue, Shunfa Zhou, Konggang Qu, Ying Li, Weiwei Cai 2020, 47(8): 317-323.  DOI: 10.1016/j.jechem.2020.02.005 摘要 ( 7 )   The conventional liquid electrolytes (LEs) have a high level of ionic conductivity;however.they often suffer from the poor processability and safety risks of potential leakage.Although solid-state electrolytes (SSEs) can solve these inherent problems of LEs.the ionic conductivity of most SSEs is several magnitudes lower than these of LEs.Herein.we report a novel strategy by building liquid ion-transport channels in a solid framework and prepared an electrolyte-locked separator (ELS) using a collagen fiber membrane (CFm).The liquid electrolyte was primarily infiltrated in the smaller voids of CFm.and its ionic conductivity could attain to 9.0×10-3 S cm-1 when the electrolyte absorption (EA) reached up to 112.0%.After centrifuging treatment.the electrolyte retentions (ER) and ionic conductivities of ELS were 108.93% and 8.37×10-3 S cm-1.respectively.which were much higher than those of commercial cellulose separator (CS).exerting excellent liquid-locking performances.In particular.the electrical double-layer capacitors (EDLC) assembled by ELS or CS were characterized and exhibited similar electrochemical performance.demonstrating the satisfactory ability and applicability of ELS for commercial use.In addition.the ELSbased EDLC exhibited favorable flexibility with relative lower loss of capacitance under different angles of bending.

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A collagen-based electrolyte-locked separator enables capacitor to have high safety and ionic conductivity Heng Xu, Yaping Wang, Xuepin Liao,bi Shi 2020, 47(8): 324-332.  DOI: 10.1016/j.jechem.2020.02.001 摘要 ( 12 )   Water splitting by electrolysis is an appealing pathway for sustainable hydrogen production.The practical performance of water splitting is highly dependent on the efficiency of electrocatalysts.which can promote the anodic oxygen evolution reaction (OER) or cathodic hydrogen evolution reaction (HER).Downsizing the metal nanostructures to atomic level to construct single-atom catalysts (SACs) has attracted enormous attention due to its distinct advantages in maximizing the efficiency of metal atom utilization and enhancing activity over corresponding metal nanoparticles.Research on SACs towards electrochemical water splitting application is an emerging field and intensive investigations have been focused on their rational syntheses and applications in HER/OER.In this review.we focus on the wet chemical method developed to prepare non-noble metal based SACs with an emphasis on the synthetic strategies and structure-activity relationship between single metal atoms and catalytic activity.Finally.the challenges and future opportunities for application of single-atom catalysts in water splitting are briefly addressed.

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Non-noble metal single-atom catalysts prepared by wet chemical method and their applications in electrochemical water splitting Wei Liu, Hongxiu Zhang,chuanming Li, Xin Wang, Jingquan Liu, Xingwang Zhang 2020, 47(8): 333-345.  DOI: 10.1016/j.jechem.2020.02.020 摘要 ( 36 )