查看更多>>摘要：Zinc-ion batteries(ZIBs)are considered to be one of the most promising candidates to replace lithium-ion batteries(LIBs)due to the high theoretical capacity,low cost and intrinsic safety.However,zinc den-drites,hydrogen evolution reaction,surface passivation and other side reactions will inevitably occur during the charging and discharging process of Zn anode,which will seriously affect the cycle stability of the battery and hinder its practical application.The etching strategy of Zn anode has attracted wide attention because of its simple operation and broad commercial prospects,and the etched Zn anode can effectively improve its electrochemical performance.However,there is no comprehensive review of the etching strategy of Zn anode.This review first summarizes the challenges faced by Zn anode,then puts forward the etching mechanisms and properties of acid,salt and other etchants.Finally,based on the above discussion,the challenges and opportunities of Zn anode etching strategy are proposed.
Pier Giorgio SchiaviAndrea Giacomo MarraniOlga RussinaLudovica D'Annibale...
144-153页
查看更多>>摘要：Lithium recovery from end-of-life Li-ion batteries(LIBs)through pyro-and hydrometallurgical recycling processes involves several refining stages,with high consumption of reagents and energy.A competitive technological alternative is the electrochemical oxidation of the cathode materials,whereby lithium can be deintercalated and transferred to an electrolyte solution without the aid of chemical extracting com-pounds.This article investigates the potential to selectively recover Li from LIB cathode materials by direct electrochemical extraction in aqueous solutions.The process allowed to recovering up to 98％of Li from high-purity commercial cathode materials(LiMn2O4,LiCoO2,and LiNi1/3Mn1/3Co1/3O2)with a far-adaic efficiency of 98％and negligible co-extraction of Co,Ni,and Mn.The process was then applied to recover Li from the real waste LIBs black mass obtained by the physical treatment of electric vehicle bat-tery packs.This black mass contained graphite,conductive carbon,and metal impurities from current col-lectors and steel cases,which significantly influenced the evolution and performances of Li electrochemical extraction.Particularly,due to concomitant oxidation of impurities,lithium extraction yields and faradaic efficiencies were lower than those obtained with high-purity cathode materials.Copper oxidation was found to occur within the voltage range investigated,but it could not quantitatively explain the reduced Li extraction performances.In fact,a detailed investigation revealed that above 1.3 V vs.Ag/AgCl,conductive carbon can be oxidized,contributing to the decreased Li extraction.Based on the reported experimental results,guidelines were provided that quantitatively enable the extraction of Li from the black mass,while preventing the simultaneous oxidation of impurities and,consequently,reducing the energy consumption of the proposed Li recovery method.
查看更多>>摘要：In the scope of developing new electrochemical concepts to build batteries with high energy density,chloride ion batteries(CIBs)have emerged as a candidate for the next generation of novel electrochemical energy storage technologies,which show the potential in matching or even surpassing the current lithium metal batteries in terms of energy density,dendrite-free safety,and elimination of the depen-dence on the strained lithium and cobalt resources.However,the development of CIBs is still at the initial stage with unsatisfactory performance and several challenges have hindered them from reaching com-mercialization.In this review,we examine the current advances of CIBs by considering the electrode material design to the electrolyte,thus outlining the new opportunities of aqueous CIBs especially com-bined with desalination,chloride redox battery,etc.With respect to the developing road of lithium ion and fluoride ion batteries,the possibility of using solid-state chloride ion conductors to replace liquid electrolytes is tentatively discussed.Going beyond,perspectives and clear suggestions are concluded by highlighting the major obstacles and by prescribing specific research topics to inspire more efforts for CIBs in large-scale energy storage applications.
查看更多>>摘要：The electrochemical CO2 reduction reaction(CO2RR)to controllable chemicals is considered as a promis-ing pathway to store intermittent renewable energy.Herein,a set of catalysts based on copper-nitrogen-doped carbon xerogel(Cu-N-C)are successfully developed varying the copper amount and the nature of the copper precursor,for the efficient CO2RR.The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE),technique still rarely explored for CO2RR.For compar-ison,products are also characterized by online gas chromatography in a H-cell.The as-synthesized Cu-N-C catalysts are found to be active and highly CO selective at low overpotentials(from-0.6 to-0.8 V vs.RHE)in 0.1 M KHCO3,while H2 from the competitive water reduction appears at larger overpotentials(-0.9 V vs.RHE).The optimum copper acetate-derived catalyst containing Cu-N4 moieties exhibits a CO2-to-CO turnover frequency of 997 h-1 at-0.9 V vs.RHE with a H2/CO ratio of 1.8.These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis prod-ucts from CO2RR.
查看更多>>摘要：Combination of CO2 capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO3-to high-value chemicals is a promising route of low cost and high efficiency.The electro-chemical reduction of HCO3-is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO3-to CO2 and CO2 electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni cen-ter,the CO2 electroreduction(CO2ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing*H over N and boosting the first proton coupled electron transfer pro-cess of CO2ER,i.e.,*+e-+*H+*CO2→*COOH.As a result,the obtained catalyst exhibits a high faradaic effi-ciency(FEco～98％)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h-1,outcompeting most of the reported Ni SACs.More importantly,an extre-mely high FEco of 90％is achieved at 50 mA cm-2 in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO2ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO3-to high-value chemicals.
查看更多>>摘要：High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conver-sion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for effi-cient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm-2 at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excel-lent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved elec-trocatalytic reaction mechanism for the in-situ generated nickel-iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced cat-alytic activity and durability.These findings provide promising strategies for the rational design of non-noble metal OER catalysts.
查看更多>>摘要：The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic performance.In this study,we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid sys-tem.Specifically,electrons were transferred from the metal-based species to N-doped carbon,while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel.This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo2C@nitrogen-doped carbon catalyst,with a half-wave potential of 0.91 V towards oxygen reduction reaction(ORR)and a low over-potential of 290 mV at 10 mA cm-2 towards oxygen evolution reaction(OER)under alkaline conditions.Additionally,the Fe-Ni/Mo2C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h gZn-1)and excellent cycling stability(200 h)in a Zn-air battery.Theoretical calculations revealed that Mo2C effectively inhibited charge transfer from Fe to the support,while secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy region.This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and OER.Consequently,our findings underscore the poten-tial of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.
查看更多>>摘要：Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered struc-ture on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi0.83Co0.06Mn0.11O2 cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li+transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li+diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary par-ticles,enabling enhanced Li+diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This pre-cursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.
查看更多>>摘要：Lithium-oxygen batteries are a promising technology because they can greatly surpass the energy density of lithium-ion batteries.However,this theoretical characteristic has not yet been converted into a real device with high cyclability.Problems with air contamination,metallic lithium reactivity,and complex discharge and charge reactions are the main issues for this technology.A fast and reversible oxygen reduction reaction(ORR)is crucial for good performance of secondary batteries',but the partial knowl-edge of its mechanisms,especially when devices are concerned,hinders further development.From this perspective,the present work uses operando Raman experiments and electrochemical impedance spec-troscopy(EIS)to assess the first stages of the discharge processes in porous carbon electrodes,following their changes cycle by cycle at initial operation.A growth kinetic formation of the discharge product sig-nal(Li2O2)was observed with operando Raman,indicating a first-order reaction and enabling an analysis by a microkinetic model.The solution mechanism in the evaluated system was ascribed for an equivalent circuit with three time constants.While the time constant for the anode interface reveals to remain rel-atively constant after the first discharge,its surface seemed to be more non-uniform.The model indicated that the reaction occurs at the Li2O2 surface,decreasing the associated resistance during the initial dis-charge phase.Furthermore,the growth of Li2O2 forms a hetero-phase between Li2O2/electrolyte,while creating a more compact and homogeneous on the Li2O2/cathode surface.The methodology here described thus offers a way of directly probing changes in surface chemistry evolution during cycling from a device through EIS analysis.
查看更多>>摘要：The incorporation of partial A-site substitution in perovskite oxides represents a promising strategy for precisely controlling the electronic configuration and enhancing its intrinsic catalytic activity.Conventional methods for A-site substitution typically involve prolonged high-temperature processes.While these processes promote the development of unique nanostructures with highly exposed active sites,they often result in the uncontrolled configuration of introduced elements.Herein,we present a novel approach for synthesizing two-dimensional(2D)porous GdFeO3 perovskite with A-site strontium(Sr)substitution utilizing microwave shock method.This technique enables precise control of the Sr con-tent and simultaneous construction of 2D porous structures in one step,capitalizing on the advantages of rapid heating and cooling(temperature～1100 K,rate～70 K s-1).The active sites of this oxygen-rich defect structure can be clearly revealed through the simulation of the electronic configuration and the comprehensive analysis of the crystal structure.For electrocatalytic oxygen evolution reaction applica-tion,the synthesized 2D porous Gd0.8Sr0.2FeO3 electrocatalyst exhibits an exceptional overpotential of 294 mV at a current density of 10 mA cm-2 and a small Tafel slope of 55.85 mV dec-1 in alkaline elec-trolytes.This study offers a fresh perspective on designing crystal configurations and the construction of nanostructures in perovskite.
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