Realizing high-performance Na_(3)V_(2)(PO_(4))_(2)O_(2)F cathode for sodium-ion batteries via Nb-doping

作     者：Jie Wang Yifeng Yuan Xianhui Rao Min’an Yang Doudou Wang Ailing Zhang Yan Chen Zhaolin Li Hailei Zhao Jie Wang;Yifeng Yuan;Xianhui Rao;Min'an Yang;Doudou Wang;Ailing Zhang;Yan Chen;Zhaolin Li;Hailei Zhao

作者机构：School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Beijing Municipal Key Lab of Advanced Energy Materials and TechnologiesBeijing 100083China 

出 版 物：《矿物冶金与材料学报:英文版》 (International Journal of Minerals,Metallurgy and Materials)

年 卷 期：2023年第30卷第10期

页      面：1859-1867页

核心收录：

学科分类：081702[工学-化学工艺] 0808[工学-电气工程] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：supported by the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (No.FRFIDRY-21-023) the Beijing Natural Science Foundation (Nos.2194079 and 2222062) the National Natural Science Foundation of China (Nos.52074023 and 52102205)。 

主　　题：sodium vanadium fluorophosphate cathode doping rate capability sodium-ion batteries 

摘      要：Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.