High-entropy oxides(HEOs)and medium-entropy oxides(MEOs)are new types of single-phase solid solution materials.MEOs have rarely been reported as positive electrode material for sodium-ion batteries(SIBs).In this study,we first proposed the concept of the application of MEOs in SIBs.P2-type 3-cation oxide Na2/3Ni1/3Mn1/3Fe1/3O2(NaNMF)and 4-cation oxide Na2/3Ni1/3Mn1/3Fe1/3-xAlxO2(NaNMFA)were prepared using the solid-state method,rather than the doping technology.In addition,the importance of the concept of entropy stabilization in material performance and battery cycling was demonstrated by testing 3-cation(NaNMF)and 4-cation(NaNMFA)oxides in the same system.Thus,NaNMFA can provide a reversible capacity of about 125.6 mAh·g1 in the voltage range of 2-4.2 V,and has enhanced cycle stability.The capacity and decay law of the MEO batteries indicate that the configurational entropy(1.28 R(NaNMFA)＞1.10 R(NaNMF))of the cationic system,is the main factor affecting the structural and cycle stability of the electrode material.This work emphasizes that the rational design of MEOs with novel structures and different electrochemically active elements may be the strategy for exploring high-performance SIB cathode materials in next-generation energy storage devices.

Shengxue YAN;Shaohua LUO;Liu YANG;Jian FENG;Pengwei LI;Qing WANG;Yahui ZHANG;Xin LIU

School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province,School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,China;School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China

先进陶瓷（英文版）

[1]Shengxue YAN;Shaohua LUO;Liu YANG;Jian FENG;Pengwei LI;Qing WANG;Yahui ZHANG;Xin LIU-.Novel P2-type layered medium-entropy ceramics oxide as cathode material for sodium-ion batteries)[J].先进陶瓷（英文版）,2022(01):158-171

HEOs,MEOs,NaNMF,xAlxO2,NaNMFA

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