Research progress on carbon anode materials in potassium-ion batteries

Aprotic potassium-ion batteries (KIBs) have drawn much attention owing to their high energy density and low cost, and abundant potassium resources. The realization of electrochemical potassiation/depotassiation in commercial graphite is of great significance to the practical application of KIBs. However, some tough issues still exist, such as the huge volume expansion of the graphite anodes, the fast decay of capacity and the poor rate performance. Researchers have tried to improve the electrochemical performance of KIBs by developing other anode candidate materials, including various carbon materials, metal oxides, and transition metal compounds. To date, the majority of studies have focused on carbon materials because of their relatively simple preparation, low cost, and environmental safety. In this review, the latest research progress on carbon anode materials for KIBs is systematically summarized. The synthesis methods and the storage mechanism of the carbon anodes with excellent electrochemical performance are summarized. Research prospects for KIBs are also proposed.