▎ 摘　　要

NOVELTY - A potassium ion battery comprises anode piece, potassium ion battery electrolyte and cathode piece. The anode piece comprises conductive carbon, binder and anode active material. The anode active material is potassium-manganese-iron-based prussian white. The cathode piece comprises conductive carbon, binder and cathode active material. The cathode active material is sulfurized polyacrylonitrile. USE - Potassium ion battery. ADVANTAGE - The battery can stably circulate 800 cycles under current density of 300 mA/g, is environment-friendly, has simple whole preparation process, low reaction energy consumption, excellent electrochemical performance and excellent multiplying power performance and long cycle stability, uses simple to synthesize active material low cost, and exhibits energy density of 290 Wh/kg (based on sum of mass of anode and cathode active materials). DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing potassium ion battery comprising mixing conductive carbon, binder and anode active material potassium-manganese-iron-based prussian white, adding second solvent and uniformly stirring, uniformly coating on aluminum foil current collector, vacuum drying to obtain anode pole piece, mixing conductive carbon, binder and cathode active material sulfurized polyacrylonitrile, adding third solvent and uniformly stirring, uniformly coating on aluminum foil current collector or copper foil current collector, vacuum drying to obtain cathode pole piece, and assembling anode pole piece, potassium ion battery electrolyte and cathode pole piece in glove box with water and oxygen content of less than 0.1 ppm.