Achieving structurally stable O3-type layered oxide cathodes through site-specific cation-anion co-substitution for sodium-ion batteries  

作　　者：Yihao Shen Chen Cheng Xiao Xia Lei Wang Xi Zhou Pan Zeng Jianrong Zeng Liang Zhang 

机构地区：[1]Institute of Functional Nano&Soft Materials(FUNSOM),Soochow University,Suzhou 215123,Jiangsu,China [2]Institute for Advanced Study,School of Mechanical Engineering,Chengdu University,Chengdu 610106,Sichuan,China [3]Shanghai Synchrotron Radiation Facility,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China [4]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China [5]Jiangsu Key Laboratory of Advanced Negative Carbon Technologies,Soochow University,Suzhou 215123,Jiangsu,China

出　　处：《Journal of Energy Chemistry》2024年第6期411-418,I0011,共9页能源化学（英文版）

基　　金：supported by the Science and Technology Program of Suzhou(ST202304);the National Natural Science Foundation of China(12275189);the Collaborative Innovation Center of Suzhou Nano Science&Technology;the 111 project。

摘　　要：O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity.However,challenges persist in the form of uncontrollable phase transitions and intricate Na^(+)diffusion pathways during cycling,resulting in compromised structural stability and reduced capacity over cycles.This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O_(3)-NaNi_(0.5)Mn_(0.5)O_(2) to effectively address these issues.Herein,the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na^(+)diffusion pathways but also orchestrates a mild phase transition by suppressing the Na^(+)/vacancy ordering and providing strong metal-oxygen bonding strength,respectively.The as-synthesized Na_(0.95)Ca_(0.05)Ni_(0.5)Mn_(0.5)O_(1.95)F_(0.05)(NNMO-CaF)exhibits a mild O3→O3+O'3→P3 phase transition with minimized interlayer distance variation,leading to enhanced structural integrity and stability over extended cycles.As a result,NNMO-CaF delivers a high specific capacity of 119.5 mA h g^(-1)at a current density of 120 mA g^(-1)with a capacity retention of 87.1%after 100 cycles.This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na^(+)diffusion kinetics,thus paving the way for high-performance layered cathode materials in sodium-ion batteries.

关 键 词：Sodium-ion batteries O3-type layered oxides Site-specific co-doping Phase transition 

分 类 号：TM912[电气工程—电力电子与电力传动] O646.541[理学—物理化学]