Fast and highly reversible Na^(+)intercalation/extraction in Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)cathode material for high-performance Na-ion batteries  

作　　者：Xiaoqin Huang Deli Li Haijian Huang Xiao Jiang Zeheng Yang Weixin Zhang 

机构地区：[1]School of Chemistry and Chemical Engineering,Hefei University of Technology,Hefei 230009,China [2]Anhui Key Laboratory of Controllable Chemical Reaction&Material Chemical Engineering,Hefei 230009,China

出　　处：《Nano Research》2021年第10期3531-3537,共7页纳米研究（英文版）

基　　金：The authors are grateful to the financial supports from the National Natural Science Foundation of China(NSFC)(Nos.91834301,91534102,and 21808046);Anhui Provincial Science and Technology Department Foundation(No.201903a05020021).

摘　　要：P2-type layered Na_(0.67)MnO_(2)has been considered to be a promising candidate cathode material for sodium ion batteries.Nevertheless,the undesired phase transitions during operation and the large Na^(+)radius induced sluggish ion diffusion remain the stumbling blocks to realize its high performance.Herein,we propose a Zn/Mg co-doping strategy,which is proved to have bifunctional effects.First,relative to the pristine P2-Na_(0.67)MnO_(2)and the single-ion(Zn/Mg)doped samples,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a lower Mn^(3+)/Mn^(4+)ratio and a higher lattice O content,which facilitate the structural stability of the cathode material.More intriguingly,the Zn/Mg co-doping gives rise to enlarged interplanar spacing,which provides spacious ion diffusion channels for fast Na^(+)intercalation/extraction.As a result,the Zn/Mg dual-doped sample exhibits a high Na^(+)diffusion coefficient and a solid-solution reaction during charge/discharge,with a cell volume change determined to be only 0.55%.Taking advantages of the above favorable features,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a high rate performance with 67.2 mAh·g^(-1)delivered at 10 C and a decent cycling stability with a capacity retention of 93.8%achieved at 1 C after 100 cycles.This work introduces the Zn/Mg co-doping strategy to simultaneously improve the cycling stability and rate capability of P2-Na_(0.67)MnO_(2),which may offer a promising avenue for further performance enhancement of the layered Na-ion batteries cathode materials.

关 键 词：Na-ion batteries cathode materials CO-DOPING Na-ion diffusion structural stability 

分 类 号：TM912[电气工程—电力电子与电力传动]