An intercalation compound for high-safe K metal batteries

K metal batteries, with high electrochemical performance and low-cost, hold great potential to be one of alternatives to lithium-ion batteries. However, the intrinsic high reactivity of K metal electrode limits their application. To enhance the safety of K metal batteries, a graphite-intercalation-compound of K (K-GIC) is prepared as an anode instead of K metal in this work. The K-GIC symmetric batteries show excellent cycling stability due to suppressing dendrite and alleviating volume expansion which are resulted from the interlayer insertion/extraction mechanism and reduced affinity energy of K. Moreover, the K-GIC compound exhibits good environmental stability in contact with air and water. Our work shows that K-GIC as an anode material may promote the application of safe and high-performance K metal batteries.