Degradation analysis and doping modification optimization for high-voltage P-type layered cathode in sodium-ion batteries  

作　　者：Bao Zhang Yi Zhao Minghuang Li Qi Wang Lei Cheng Lei Ming Xing Ou Xiaowei Wang 

机构地区：[1]National Engineering Laboratory for High-Efficiency Recovery of Refractory Nonferrous Metals,School of Metallurgy and Environment,Central South University,Changsha 410083,Hunan,China [2]Zhejiang Power New Energy Co.,LTD,Zhuji 311800,Zhejiang,China

出　　处：《Journal of Energy Chemistry》2024年第2期1-9,I0002,共10页能源化学（英文版）

基　　金：the financial support from the National Natural Science Foundation of China(52202338)。

摘　　要：Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.

关 键 词：Soidum ion batteries Layer cathode materials P-TYPE High-voltage performance Degradation analysis 

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