Rational design of metal selenides nanomaterials for alkali metal ion (Li⁺/Na⁺/K⁺) batteries: current status and perspectives

Recently, metal selenides have obtained widespread attention as electrode materials for alkali (Li⁺/Na⁺/K⁺) batteries due to their promising theoretical capacity and mechanism. Nevertheless, metal selenides, similar to metal oxides and sulfides, also suffer from severe volume explosion during repeated charge/discharge processes, which results in the structure collapse and the following pulverization of electrode materials. Hence, it leads to poor cycle stability and influencing their further application. In order to solve these issues, some special strategies, including elemental doping, coupling with carbon materials, synthesis of the bimetal selenides with heterostructure, etc., have been gradually applied to design novel electrode materials with outstanding electrochemical performance. Herein, the recent research progress on metal selenides as anodes for alkali ion batteries is summarized, including the regulation of crystal structure, synthesis strategies, modification methods, and electrochemical mechanisms and kinetics. Besides, the challenges of metal selenides and the perspective for future electrode material design are proposed. It is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion (Li⁺/Na⁺/K⁺) batteries.