▎ 摘　　要

NOVELTY - Preparing bismuth element/Prussian blue framework-graphene composite material comprises (i) dissolving potassium hexacyanoferrate in deionized water, and ultrasonic treating until the red particles are completely dissolves, then adding polyvinylpyrrolidone, ultrasonic dissolving, placing the above solution in a 60-90 degrees C blast oven for 1-24 hours, centrifuging and washing, (ii) dissolving bismuth(III) nitrate in deionized water to prepare bismuth(III) nitrate solution, and then adding the blue-black precursor powder to the solution, stirring, centrifuging and washing for 3-4 times, then placing in an oven at 60 degrees C and drying for 12 hours to obtain blue reaction product, and (iii) dispersing the above blue reaction product in 20 wt.% aqueous graphene solution, ultrasonic dispersing, and freeze-drying for 24 hours to obtain blue-gray powder, then transferring into a tube furnace with a mixed atmosphere of argon and hydrogen, carrying out reduction reaction. USE - The composite material is useful as cathode material for potassium ion battery (claimed). DETAILED DESCRIPTION - Preparing bismuth element/Prussian blue framework-graphene composite material comprises (i) dissolving potassium hexacyanoferrate in deionized water, and ultrasonic treating until the red particles are completely dissolves, then adding polyvinylpyrrolidone, ultrasonic dissolving, placing the above solution in a 60-90 degrees C blast oven for 1-24 hours, centrifuging and washing for 3-4 times, then placing in a 60 degrees C oven to dry the blue-black precursor powder for 12 hours, (ii) dissolving bismuth(III) nitrate in deionized water to prepare bismuth(III) nitrate solution, and then adding the blue-black precursor powder to the solution, stirring in a water bath at 40-80 degrees C for 1-24 hours, centrifuging and washing for 3-4 times, then placing in an oven at 60 degrees C and drying for 12 hours to obtain blue reaction product, and (iii) dispersing the above blue reaction product in 20 wt.% aqueous graphene solution, ultrasonic dispersing for two hours, and freeze-drying for 24 hours to obtain blue-gray powder, then transferring into a tube furnace with a mixed atmosphere of argon and hydrogen, carrying out reduction reaction at 400-800 degrees C at a heating rate of 2-5 degrees C/minute for 1-12 hours, and cooling to obtain final product.