Enhanced performance of core-shell structured sodium manganese hexacyanoferrate achieved by self-limiting Na^(+)-Cs^(+)ion exchange for sodium-ion batteries  

作　　者：Yan-Dong Guo Ji-Cheng Jiang Jian Xie Xin Wang Jing-Ze Li Dong-Huang Wang Ai-Jun Zhou 

机构地区：[1]School of Materials and Energy,University of Electronic Science and Technology of China,Chengdu,611731,China [2]Yangtze Delta Region Institute(Huzhou),University of Electronic Science and Technology of China,Huzhou,313001,China [3]State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou,310027,China

出　　处：《Rare Metals》2022年第11期3740-3751,共12页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.52172184 and 51763022);the Fundamental Research Funds for the Central Universities(No.ZYGX2019J024)。

摘　　要：Sodium manganese hexacyanoferrate(NaMnHCF)is a promising cathode material for sodiumion batteries(SIBs)due to its low cost and high energy density.The Jahn-Teller effect of Mn,however,leads to the poor structural stability of NaMnHCF,resulting in undesired electrochemical performance.Herein,we developed a novel coating strategy and obtained a coreshell structured NaMnHCF through facile Na^(+)-Cs^(+)ion exchange,which naturally produced a robust and insoluble Cs-rich surface layer(CsMnHCF)with several nanometers in thickness on pristine NaMnHCF.It is shown that the Csrich surface plays a positive role in the stability of the NaMnHCF structure by prohibiting the leakage of crystal water,stabilizing the solid-liquid interfaces,and solidifying crystal structure.The electrochemical performance of the core-shell NaMnHCF is dramatically improved with a discharge capacity of 76.3 mAh·g^(-1)after 1000 cycles at 1.0 C and a reversible capacity of 87.0 mAh·g^(-1)at 10.0 C,which is much superior to that of the pristine NaMnHCF with only 26.6 mAh·g^(-1)after 400 cycles and 31 mAh·g^(-1)at 10.0 C.This work reports a new method for the synthesis of core-shell NaMnHCF and provides a novel perspective for the development of advanced NaMnHCF cathode for SIBs.

关 键 词：Sodium manganese hexacyanoferrate Ion-exchange Core-shell structure Surface modification Sodium-ion batteries 

分 类 号：TM912[电气工程—电力电子与电力传动] TB34[一般工业技术—材料科学与工程]