▎ 摘　　要

NOVELTY - The method involves using lithium hexafluorophosphate as electrolyte, graphite or graphene as negative electrode of potassium ion battery for pre-circulating treatment at 50degreesC high temperature. The coordination of the solvent molecule and KPF6 is adjusted. A stable and uniform organic-rich passivation layer is formed on the graphite or graphene cathode surface. The 1M lithium hexafluorophosphate is set to use ethylene glycol dimethyl ether and ethylene carbonate as the solvent, KPF6 as the solute, and the volume ratio of the solvent is 1:1. The charge-discharge cycle treatment is performed 3-15 times at a current density of 50mAh g-1. USE - Method for improving stability of graphite or graphene cathode of potassium ion battery (claimed), used in large scale energy storage system. ADVANTAGE - The graphite cathode shows excellent electrochemical performance and structure stability. The potassium ion battery provides excellent cycle stability and electrochemical stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a potassium ion battery.