High-capacity graphene-confined antimony nanoparticles as a promising anode material for potassium-ion batteries

K-ion batteries (KIBs) have attracted increasing attention as a potential alternative to Li-ion batteries (LIBs) due to the abundance of resources and the low cost of potassium. However, their power and energy densities are very limited because of the larger ionic radius and greater mass of potassium ions compared with lithium ions. Herein, the electrochemical alloying of potassium with antimony is reported in a nonaqueous KIBs, which shows a high capacity of 600 mA h g−1 at 100 mA g−1 and a good rate capability of 180 mA h g−1 at 1 A g−1. Ex situ measurements indicate that potassium can react threefold with antimony to form K3Sb. In a proof-of-concept experiment, an Sb/RGO || PBA cell showed a high power density of 981 W kg−1 and an energy density of 82 Wh kg−1. This work will aid the design of high-performance KIBs and will contribute to the development of sustainable green power sources.