Bismuth oxychloride nanoflake assemblies as a new anode for potassium ion batteries

This work reports the first demonstration of bismuth oxyhalides as anode materials in potassium-ion batteries. BiOCl nanoflake assemblies deliver high capacities of 367 mA h g−1 at 50 mA g−1 and 175 mA h g−1 at 1 A g−1. The formation of K–Bi alloys at an early stage of potassiation is observed.