Developments and prospects of carbon anode materials in potassium-ion batteries

Potassium-ion batteries (PIBs) have garnered significant interest due to their abundant resources, wide distribution and low price, emerging as an ideal alternative to lithium-ion batteries for energy storage systems. As one of the key components, anode materials act as a crucial role in the specific capacity, energy density, power density and service life of PIBs, so it is highly significant to conduct a comprehensive investigation on them. Carbon materials are widely employed as the anode for PIBs because of their advantages of environmental friendliness, abundant raw materials and diverse structures. According to the structural differences, carbon materials are mainly distinguished as crystalline carbon represented by graphite and graphene, and soft carbon and hard carbon existing in amorphous state. Different types of carbon materials have special ion storage mechanisms, storage capacity and cycling stability. Herein, it is meaningful to summarize and discuss the characteristics and research progress in carbon anode materials for PIBs in recent years. Firstly, according to the development status and application prospect of graphite, graphene, soft carbon, and hard carbon, we deeply generalize the electrochemical performance and potassium storage mechanism. Then we dig out the key problems faced by different carbon materials and arrange various modification design and solving strategies of novel carbon anodes. Finally, we expound the importance of carbon anode materials as the anode and PIBs, explore the application potential of current and emerging carbon anode materials, and put forward some suggestions and prospects for the future development of carbon materials.