Nitrogen-doped mesoporous carbon as an anode material for high performance potassium-ion batteries

Searching for alternatives to lithium-ion batteries, potassium ion batteries (PIBs) have received a lot of research interest due to the abundance and low cost of potassium resources. However, studies on suitable electrode materials for PIBs are still in infancies, and much remains to be studied and investigated. Here, a nitrogen-doped amorphous ordered mesoporous carbon (NMC) having large surface area, suitable porous structure and abundant defects is reported as an anode material for high performance PIBs. The material delivers a high initial reversible capacity of 336.1 mA h g−1 at 50 mA g−1. A high reversible charge capacity of 251.2 mA h g−1 is retained at 100 mA g−1 after 450 cycles, which corresponds to 107.5% of the initial reversible capacity. Even at a large current density of 1000 mA g−1, it can maintain 101.1 mA h g−1 after 1000 cycles. The large surface area and mesoporous structure of NMC possess large electrochemical active surface and facilitate the transport of K ions. Moreover, the introduction of N increases the active sites for K ions storage, which benefit to long-term cycling stability. Surface-dominated K ions storage is also verified by quantitative kinetics analysis. We hope this study will serve as a trigger, and contribute towards the development of anode materials for PIBs.