Creative high-entropy strategy: a booster to the design of anode materials for high-energy lithium-ion batteries

Nowadays, lithium-ion batteries (LIBs) have held the dominant role in various electric energy storage devices. With the rapid development of new energy vehicles and large-scale energy storage fields, there is an urgent demand for high-energy LIBs. While anode materials are important for determining energy density, commercialized graphite cannot meet the requirement for high specific capacity, and silicon-based materials always suffer from poor cycle stability. High-entropy oxides (HEOs) are emerging as a new category of single-phase material consisting of multiple principal elements with equimolar or quasi-equimolar ratios. Due to the design flexibility and interaction between multiple functional elements, HEOs can display improved comprehensive properties as LIBs anodes, which is expected to be a potential solution for high-energy LIBs. Herein, this review provides an extensive overview of the recent progress of HEOs anode materials in LIBs. The electrochemical properties of three typical HEOs are summarized, the synthesis methods for HEOs are subsequently elaborated, and current lithium storage mechanisms are analyzed in detail. Finally, the modification strategies are offered for further research to promote the development of HEO anodes in LIBs, including composition manipulations and the enhancement of conversion kinetic. It is aimed to propose practical guidance for exploration of HEO anode materials in next-generation high-energy batteries.