Cocoon-shaped P3-type K0.5Mn0.7Ni0.3O2 as an advanced cathode material for potassium-ion batteries  

作　　者：Liping Duan Jianzhi Xu Yifan Xu Ruiqi Tian Yingying Sun Chuannan Zhu Xiangyin Mo Xiaosi Zhou 

机构地区：[1]Jiangsu Key Laboratory of New Power Batteries,Jiangsu Collaborative Innovation Center of Biomedical Functional Materials,School of Chemistry and Materials Science,Nanjing Normal University,Nanjing 210023,Jiangsu,China

出　　处：《Journal of Energy Chemistry》2023年第1期332-338,I0008,共8页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(22179063)。

摘　　要：Potassium ion batteries(PIBs)are emerging as potential next-generation energy storage systems on account of their low cost and high theoretical energy density.Nevertheless,they also face challenges of low specific capacity and suboptimal cycling stability.Herein,we synthesize a cocoon-like P3-type K_(0.5)Mn_(0.7)Ni_(0.3)O_(2)(KMNO)cathode material by a self-template method.The KMNO cocoons possess a hierarchical layered architecture composed of nanoparticle stacking,which can accelerate the transport kinetics of potassium ions,mitigate the stress caused by K^(+)intercalation and deintercalation,and improve structural stability.In addition,Ni can not only alleviate the Jahn-Teller distortion and suppress the phase transition to stabilize the structure,but also act as an electrochemically active element,providing the capacity of two electrons from Ni2+to Ni4+.Combining the advantages of structure and nickel substitution,the P3-type KMNO cocoons are used for electrochemical performance testing of PIB cathodes,delivering an excellent rate capability of 57.1 m A h g^(-1)at 500 m A g^(-1)and a remarkable cycling stability of 77.0%over 300 cycles at 100 m A g^(-1).Impressively,the KMNO cocoons//pitch-derived soft carbon assembled full battery exhibits superior electrochemical performance with a reversible capacity of 79.7 m A h g^(-1)at 50 m A g^(-1).Moreover,ex-situ XRD also further reveals a solid solution phase reaction with a volume change of only 1.46%.This work furnishes a suitable approach to fabricating highperformance layered oxide cathodes for PIBs with outstanding cycling stability and rate capability.

关 键 词：Layered metal oxides Cathode Potassium-ion batteries COCOONS Ex-situ XRD 

分 类 号：TM912[电气工程—电力电子与电力传动]