Covalency competition induced selective bond breakage and surface reconstruction in manganese cobaltite towards enhanced electrochemical charge storage

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外文摘要：Manganese cobaltite(MnCo2O4)is a promising electrode material because of its attractive redox chemistry and excellent charge storage capability.Our previous work demonstrated that the octahedrally-coordinated Mn are prone to react with the hydroxyl ions in alkaline electrolyte upon electrochemical cycling and separates on the surface of spinel to reconstruct into δ-MnO2 nanosheets irreversibly,thus results in a change of the reaction mechanism with K+ion intercalation.However,the low capacity has greatly limited its practical application.Herein,we found that the tetrahedrally-coordinated Co2+ions were leached when MnCo2O4 was equilibrated in 1 mol L-1 HCl solution,leading to the formation of layered CoOOH on MnCo2O4 surface which is originated from the covalency competition induced selective breakage of the CoT-O bond in CoT-O-CoO and subsequent rearrangement of free CoO6 octahedra.The as-formed CoOOH is stable upon cycling in alkaline electrolyte,exhibits conversion reaction mechanism with facile proton diffusion and is free of massive structural evolution,thus enables utilization of the bulk electrode material and realizes enhanced specific capacity as well as facilitated charge transfer and ion diffusion.In general,our work not only offers a feasible approach to deliberate modification of MnCo2O4's surface structure,but also provides an in-depth understanding of its charge storage mechanism,which enables rational design of the spinel oxides with promising charge storage properties.

外文关键词：

Manganese cobaltiteTetrahedrally-coordinated Co2+leachingSelective bond breakageSurface reconstructionCharge storage mechanisms

作者：

Peng Gao、Pei Tang、Ying Mo、Peitao Xiao、Wang Zhou、Shi Chen、Hongliang Dong、Ziwei Li、Chaohe Xu、Jilei Liu

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作者单位：

College of Materials Science and Engineering,Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy,Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology,Hunan University,Changsha,Hunan,410082,China

Department of Materials Science and Engineering,National University of Defense Technology,Changsha,Hunan,410073,China

Joint Key Laboratory of the Ministry of Education,Institute of Applied Physics and Materials Engineering,University of Macau,Avenida da Universidade,Taipa,Macau,999078,China

Center for High Pressure Science and Technology Advanced Research,Pudong,Shanghai,201203,China

College of Aerospace Engineering,Chongqing University,Chongqing,400044,China

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基金：

国家重点研发计划国家自然科学基金国家自然科学基金国家自然科学基金湖南省自然科学基金Hunan Provincial Department of Education Outstanding Youth ProjectMacau Science and Technology Development FundMacau Science and Technology Development Fund

项目编号：

2022YFE020630022209047U21A2081220750742020JJ503523B0037Macau SARFDCT-0096/2020/A2

出版年：

2024

DOI：

10.1016/j.gee.2022.10.003

绿色能源与环境(英文)

CSTPCD

ISSN：

年,卷(期)：2024.9(5)

参考文献量63