▎ 摘　　要

NOVELTY - A nano cobalt / nitrogen doped graphene composite material comprise cobalt nanoparticles having particle diameter of 5 nm which exists in the form of elemental cobalt. USE - Nano cobalt / nitrogen doped graphene composite material used in electrocatalytic water decomposition and ion membrane exchange batteries. ADVANTAGE - The nano cobalt / nitrogen doped graphene composite material has excellent catalytic performance for oxygen reduction reaction and reaches overpotential of 300 mV. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of composite material which involves adding dimethylimidazole and methanol-ethanol anhydrous solution to graphene oxide aqueous dispersion in drops, stirring to obtain a mixed solution, adding methanol-ethanol anhydrous solution of cobalt salt to the mixed solution in drops, uniformly stirring, centrifuging the mixture, washing with deionized water and absolute ethanol, drying at 60 degrees C, grinding and heating to 550 plus minus 10 degrees C at a heating rate of 2 degrees C/minute for 8 hours under mixed gas of argon and hydrogen.