▎ 摘　　要

NOVELTY - The preparation method of graphene nano-sieve material involves (1) soaking a metal substrate in 2-20 mg/ml oxidized graphene aqueous solution, reacting at 60-80 degrees C for 6-60 hours, and taking out the metal substrate to obtain three-dimensional graphene assembly, (2) freeze-drying the obtained graphene assembly to obtain dried three-dimensional graphene material, and (3) calcining the dried three-dimensional graphene material obtained in the step (2) at 400-1100 degrees C for 0.5-3 hours in inert atmosphere, cooling, and washing. USE - Preparation method of graphene nano-sieve material for electrode material or composite material of energy storage and conversion device (claimed). ADVANTAGE - The method enables preparation of graphene nano-sieve material, and simultaneously realizes the controllability of the pore size of the graphene nano-sieve material. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for use of graphene nano-sieve material in electrode material or composite material of energy storage and conversion device.