Heteroatom-doped carbon anode materials for potassium-ion batteries: From mechanism, synthesis to electrochemical performance

Carbonaceous materials are attractive anode candidates for potassium-ion batteries (PIBs) because of their cost-effectiveness, high conductivity, and considerable architecture. However, these carbon materials usually exhibit slow diffusion kinetics and huge volume variation induced by the large ionic size of K-ions, resulting in poor rate capability and cycling stability. Compared to pure carbon, heteroatom (N, S, P, and O)-doped carbons can well improve potassium storage performance by optimizing K-adsorption ability and conductivity, and, hence, exhibit a significant potential in PIBs. This review in-detail summarizes the recent progress of heteroatom-doped carbon anodes based on potassium storage mechanism, design or synthesis strategies, and electrochemical performance, mainly including single-, bi-, and tri-element doped carbons. Moreover, some critical issues and possible solutions for the development of heteroatom-doped carbon in the future are discussed. This review aims at providing a deep insight into the understanding, designing, and application of heteroatom-doped carbon anodes in PIBs and is expected to make an obvious effect on the exploration of other anodes.