Electrochemical Intercalation of Potassium into Graphite

Exceptional cycling performance of graphite anode in K-ion batteries is demonstrated with a reversible capacity of 246 mAh g^–1 and 89% retention of the initial capacity after 200 cycles. Although the graphite anode experiences huge volume change and worse kinetics during K intercalation/deintercalation, the cycling stability delivered in K-ion batteries is comparable to that of Li-ion batteries using the same graphite anode. The combination of excellent electrochemical performance, the abundance and wide availability of K in earth's crust, and the well-developed technology of the graphite anode make the K-ion battery very attractive for offering a low cost battery chemistry for large-scale energy storage applications.