Unlocking iron-based mixed-phosphate cathode for sodium-ion batteries through off-stoichiometry  

作　　者：Zhaolu Liu Yongjie Cao Ning Wang Hui Yang Hao Zhang Xinyue Xu Nan Wang Jie Xu Yao Liu Junxi Zhang Yongyao Xia 

机构地区：[1]Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power,Shanghai University of Electric Power,Shanghai 200090,China [2]Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Fudan University,Shanghai 200433,China [3]School of Materials Science and Engineering,Anhui University of Technology,Ma’anshan 243002,China [4]Key Laboratory of Interfacial Physics and Technology,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China

出　　处：《Nano Research》2024年第9期8119-8125,共7页纳米研究（英文版）

基　　金：supported by Science and Technology Commission of Shanghai Municipality(No.19D.Z.2271100).

摘　　要：The off-stoichiometric iron-based phosphate(Na_(3.12)Fe_(2.44)(P_(2)O_(7))_(2),denoted as Na3.12)as a low cost and high structure stability cathode material has been widely studied for sodium-ion batteries(SIBs).However,the lower theoretical specific capacity(117 mAh·g^(-1))has seriously limited its practical application.In this work,we incorporate varying proportion of sodium-iron phosphate(NaFePO_(4))into the Na3.12 to form a series of new high specific capacity mixed-phosphates Na_(3.12+x)Fe_(2.44+x)(P_(2)O_(7))_(2)(PO_(4))x cathode materials for SIBs.After optimizing the introduction amount of NaFePO_(4)into Na_(3.12),the practical reversible of Na_(3.12+x)Fe_(2.44+x)(P_(2)O_(7))_(2)(PO_(4))_(x) increased from 92 to 125.2 mAh·g^(-1).The nano-size Na5.12Fe4.44(P_(2)O_(7))_(2)(PO_(4))_(2) cathode material shows a reversible specific capacity of 125.2 mAh·g^(-1)at 0.1 C in SIBs.Even at 60 C,it still exhibits a reversible specific capacity of 93.3 mAh·g^(-1)and keeps a capacity retention ratio of 87%after 3000 cycles at 20 C.Thereby,we present a novel approach to design a series of off-stoichiometric mixed-phosphates cathode materials for SIBs.

关 键 词：sodium-ion batteries cathode material iron-based mixed-phosphates off-stoichiometric 

分 类 号：TM912[电气工程—电力电子与电力传动]