Cu-substitution P2-Na_(0.66)Mn_(1-x)Cu_(x)O_(2) sodium-ion cathode with enhanced interlayer stability  

作　　者：Huanqing Liu Xu Gao Jun Chen Jinqiang Gao Haoji Wang Yu Mei Huan Liu Wentao Deng Guoqiang Zou Hongshuai Hou Xiaobo Ji 

机构地区：[1]State Key Laboratory of Powder Metallurgy,College of Chemistry and Chemical Engineering,Central South University,Changsha 410083,Hunan,China [2]School of Materials Science and Engineering,Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion,Hunan University of Science and Technology,Xiangtan 411201,Hunan,China

出　　处：《Journal of Energy Chemistry》2022年第12期478-485,I0012,共9页能源化学（英文版）

基　　金：financially supported by the Science and Technology Foundation of Guizhou Province(QKHZC[2020]2Y037);the Science and Technology Innovation Program of Hunan Province(2020RC4005,2019RS1004);the Innovation Mover Program of Central South University(2020CX007)。

摘　　要：P2-type Mn-based layered oxides are viewed as promising cathode materials for sodium ion battery by virtue of their high theoretical capacity.Considering that pure Na_(2/3)MnO_(2)suffers from poor cycling performances,Cu-substitution strategy is proposed to effectively alleviate this issue.However,the structural evolution mechanism of the Cu-containing samples still remains unclear.Herein,we propose that CuSubstitution P2-type Na_(0.66)Mn_(1-x)Cu_(x)O_(2)with enlarged lattice parameters are conducive to improving the interlayer structure stability through mitigating TMO_(2)slabs distortion.Proved by synchrotron XAS spectra and ex/in situ XRD,the expansion/contraction of MnO_6 octahedron is dramatically reduced with the increased Cu content,showing the facilitated Na ion diffusion.Furthermore,when the ratio of Cu to Mn reaches 1:4,the phase transition from P2 to P'2 type at the end of discharge can be suppressed,resulting in the improved interlayer skeleton stability.The Cu-containing samples with stable interlayer structure exhibit high capacity retention and outstanding rate performances(a capacity of 79.9 m Ah g^(-1)at 5C).This Cu-substitution strategy provides a promising approach to designing highly stable cathodes.

关 键 词：Sodium-ion battery Manganese-based cathode Cu-substitution In-plane distortion Jahn-Teller effect 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.12[化学工程—无机化工]