Low-cost and high-rate porous carbon anode material for potassium-ion batteries

Potassium enhances the advantages of abundant reserves, low cost, and low standard electrode potential. Therefore, potassium ion batteries have recently received a lot of attention and research as an ideal low-cost secondary battery system. In this paper, the template method is utilized to prepare porous carbon anode material for potassium ion batteries using low-cost calcium carbonate as the template and sucrose as the carbon source. The material has unordered microstructure, large specific surface area, and hierarchical porous structure formed by “macropore-mesopore-micropore”. Electrochemical test results show that the prepared porous carbon anode material has a specific capacity of 259.5 mAh·g−1 at a current density of 50 mA·g−1, and the capacity retention rate is 92.8% after 100 cycles. After the cycle, the pole piece has a flat surface without obvious cracks, indicating that the material experienced a small volume change during the potassium ion intercalation/deintercalation process. Porous carbon material exhibits good rate performance at a high current density of 2000 mAh·g−1, with a specific capacity of 129.6 mAh·g−1 after 10,000 cycles.