文献类型：期刊文献

英文题名：Enabling stable MnO2 matrix for aqueous zinc-ion battery cathodes

作者：Jiao, Yiding[1];Kang, Liqun[2];Berry-Gair, Jasper[1];McColl, Kit[1];Li, Jianwei[1];Dong, Haobo[1];Jiang, Hao[3];Wang, Ryan[2];Cora, Furio[1];Brett, Dan J. L.[2];He, Guanjie[1,2,4];Parkin, Ivan P.[1]

机构：[1]UCL, Dept Chem, Christopher Ingold Lab, 20 Gordon St, London WC1H 0AJ, England;[2]UCL, Dept Chem Engn, Torrington Pl, London WC1E 7JE, England;[3]East China Univ Sci & Technol, Sch Mat Sci & Engn, Shanghai Engn Res Ctr Hierarch Nanomat, Key Lab Ultrafine Mat,Minist Educ, 130 Meilong Rd, Shanghai 200237, Peoples R China;[4]Univ Lincoln, Sch Chem, Joseph Banks Labs, Green Lane, Lincoln LN6 7DL, England

年份：2020

卷号：8

期号：42

起止页码：22075

外文期刊名：JOURNAL OF MATERIALS CHEMISTRY A

收录：;EI(收录号：20204609475612);WOS:【SCI-EXPANDED(收录号:WOS:000585127100013)】；

基金：The authors acknowledge Diamond Light Source and electron Physical Science Imaging Centre for the allocated beamtime at E01 (session ID: MG24450). The authors acknowledge Helmholtz-Zentrum Berlin for the allocated beamtime at the ISISS beamline of BESSY II (proposal ID: 19108389-ST). The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC, EP/L015862/1, EP/R023581/1), STFC Batteries Network (ST/R006873/1), RSC Mobility Grant (M19-7656) for funding support. Via the authors' membership of the UK's HEC Materials Chemistry Consortium funded by EPSRC (EP/L000202), this work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).The authors are grateful to the UK Materials and Molecular Modelling Hub for computational resources, partially funded by EPSRC (EP/P0202194/1). The authors acknowledge the use of the UCL Kathleen High Performance Computing Facility (Kathleen@UCL) and associated support services to complete this work. Y. Jiao thanks the funding support from China Scholarship Council/University College London for the joint PhD scholarship. Y. J. thanks the support from his colleagues and families. In particular, Y. J. wants to thank H. X. for her invaluable support and encouragement over the years. Will you marry me?

语种：英文

外文关键词：Density functional theory - Zinc - Ions - Zinc compounds - Secondary batteries - Manganese oxide

摘要：The primary issue faced by MnO2 cathode materials for aqueous Zn-ion batteries (AZIBs) is the occurrence of structural transformations during cycling, resulting in unstable capacity output. Pre-intercalating closely bonded ions into the MnO2 structures has been demonstrated as an effective approach to combat this. However, mechanisms of the pre-intercalation remain unclear. Herein, two distinct delta-MnO2 (K0.28MnO2 center dot 0.1H(2)O and K0.21MnO2 center dot 0.1H(2)O) are prepared with varying amounts of pre-intercalated K+ and applied as cathodes for AZIBs. The as-prepared K0.28MnO2 center dot 0.1H(2)O cathodes exhibit relatively high specific capacity (300 mA h g(-1) at 100 mA g(-1)), satisfactory rate performance (35% capacity recovery at 5 A g(-1)) and competent cyclability (ca. 95% capacity retention after 1000 cycles at 2 A g(-1)), while inferior cyclability and rate performance are observed in K0.21MnO2 center dot 0.1H(2)O. A stable delta-MnO2 phase is observed upon cycling, with the reversible deposition of Zn4SO4(OH)(6)center dot 5H(2)O (ZSH), ion migration between electrodes and synchronous transition of Mn valence states. This work firstly and systematically reveals the role of the pre-intercalated ions via density functional theory simulations and show that above a threshold K/Mn ratio of ca. 0.26, the K ions suppress structural transformations by stabilizing the delta phase. To demonstrate its commercial potential, AZIBs with high-loading active materials are fabricated, which deliver adequate energy and power densities compared with most commercial devices.