Lithium modulated spinel high entropy oxide anode of LIBs through microwave solvothermal method

• Published in: Electrochimica acta Vol. 503; p. 144908
• Main Authors: Wang, Dan, Li, Xiao, Li, Zenghui, Yu, Yihang, Wen, Xiaojing, Wang, Qing, Liu, Yanguo, Qi, Xiwei, Wang, Zhiyuan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2024
• Subjects: Anode; High entropy oxide; Li doping; LIBs; Oxygen vacancy; High entropy oxide; Li doping; Anode; LIBs; Oxygen vacancy
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2024.144908

•Lithium modulated spinel high entropy oxides ([Lix(FeCoNiCrMn)1-x]3O4, X=0,0.05,0.15,0.25) have been fabricated through a new-type microwave solvothermal followed the heat treatment process.•The addition of Li+ in HEO increases the valence states of transition metal cations and induces more oxygen vacancies, which facilitates Li ion storage and increases ionic conductivity.•The Li induced lattice distortion together with the entropy stabilization mechanism alleviate the lattice stress, featuring the anode superior electrochemical stability. Spinel structured high entropy oxides (HEO) with three-dimensional Li+ transport channel and two different Wyckoff sites show high theoretical capacities due to multiple hypervalent ions and abundant oxygen vacancies. However, the intrinsic poor electrical conductivity of oxides and the lack of low-energy-consumption synthesis methods remain problems. Herein, Li+ with low-electronegativity is introduced into (FeCoNiCrMn)3O4 through high-efficiency microwave-assisted solvothermal method. The nano-scale high entropy oxide particles with homogeneous distribution of elements are successfully obtained in a short time. The addition of Li+ in HEO not only increases the valence states of transition metal cations to increase the number of electron transfers, but also induces more oxygen vacancies, which facilitates Li ion storage and increases ionic conductivity. The Li induced lattice distortion together with the entropy stabilization mechanism alleviate the lattice stress, featuring the anode superior electrochemical stability. The anode HEO-15 with the optimal Li content shows the specific capacity of 452.8 mAh g-1 at a current density of 500 mA g-1 after 300 cycles for LIBs, much higher than that of HEO-0 (248.9 mAh g-1). This research provides an effective method to improve the lithium storage performance of HEO.