摘要
MoS_(2) is a promising anode material in sodium-ion battery technologies for possessing high theoretical capacity.However,the sluggish Na^(+) diffusion kinetics and low electronic conductivity hinder the promises.Herein,a unique MoS_(2)/FeS_(2)/C heterojunction with abundant defects and hollow structure(MFCHHS)was constructed.The synergy of defect engineering in MoS_(2),FeS_(2),and the carbon layer of MFCHHS with a larger specific surface area provides multiple storage sites of Na^(+)corresponding to the surface-controlled process.The MoS_(2)/FeS_(2)/C heterostructure and rich defects in MoS_(2) and carbon layer lower the Na^(+) diffusion energy barrier.Additionally,the construction of MoS_(2)/FeS_(2) heterojunction promotes electron transfer at the interface,accompanying with excellent conductivity of the carbon layer to facilitate reversible electrochemical reactions.The abundant defects and mismatches at the interface of MoS_(2)/FeS_(2) and MoS_(2)/C heterojunctions could relieve lattice stress and volume change sequentially.As a result,the MFCHHS anode exhibits the high capacity of 613.1 mA h g^(-1)at 0.5 A g^(-1) and 306.1 mA h g^(-1) at 20 A g^(-1).The capacity retention of 85.0%after 1400 cycles at 5.0 A g^(-1) is achieved.The density functional theory(DFT)calculation and in situ transmission electron microscope(TEM),Raman,ex-situ X-ray photon spectroscopy(XPS)studies confirm the low volume change during intercalation/deintercalation process and the efficient Na^(+)storage in the layered structure of MoS_(2) and carbon layer,as well as the defects and heterostructures in MFCHHS.We believe this work could provide an inspiration for constructing heterojunction with abundant defects to foster fast electron and Na^(+) diffusion kinetics,resulting in excellent rate capability and cycling stability.
基金
the National Natural Science Foundation of China(NSFC)(22105059,22279112)
the Talent Introduction Program of Hebei Agricultural University(YJ201810)
the Youth Topnotch Talent Foundation of Hebei Provincial Universities(BJK2022023)
the Natural Science Foundation of Hebei Province(B2022203018)
the Fok Ying-Tong Education Foundation of China(171064)
the Natural Science Foundation of Shandong Province,China(ZR2021QE192)
the China Postdoctoral Science Foundation(2018M630747)
the 333 Talent Program of Hebei Province(C20221018)for their support。
作者简介
contributed equally:Linlin Ma;contributed equally:Xiaomei Zhou;Corresponding author:Yongfu Tang,E-mail addresses:tangyongfu@ysu.edu.cn;Corresponding author:Xiaoxian Zhao,E-mail addresses:lxzhxx@hebau.edu.cn。
