Research progress of Zn and its compounds as anode materials for potassium-ion batteries

Potassium-ion batteries (PIBs) have been regarded as promising next-generation energy storage systems due to the abundant potassium resources and their similar properties to those of lithium-ion batteries (LIBs). However, compared with LIBs, PIBs face several challenges in practical applications, mainly including low energy density, short cycle life, and underdeveloped manufacturing techniques. In recent years, extensive research has been devoted to developing novel anode materials with excellent electrochemical performance. Notably, among various anode materials, zinc (Zn) and its compounds, including ZnO, ZnS, ZnSe, ZnTe and zinc phosphides, have shown great potential owing to their high theoretical capacity, natural abundance, and diverse chemical properties. Nevertheless, such materials also suffer from significant volume expansion and poor cycling stability during charge/discharge cycles. To address these challenges, several effective strategies have been successfully employed to mitigate the aforementioned issues, such as compositing with carbon materials, doping, nanostructure design, and heterojunction engineering. This review aims to summarize the recent progress in zinc-based anode materials for PIBs, with a focus on analyzing the advantages and limitations of various materials and discussing effective strategies for performance enhancement. Finally, the remaining challenges and future research directions for Zn-based anodes in PIBs are discussed.