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. BiOCl is demonstrated as the first bismuth oxyhalide compound serving as a new anode material for potassium ion batteries.