▎ 摘　　要

NOVELTY - A self-supporting high-entropy oxide/graphene composite material comprises spinel structure high-entropy iron-nickel-manganese-chromium-copper oxide uniformly provided between graphene layers. USE - Self-supporting high-entropy oxide/graphene composite material is used as negative electrode material in sodium-ion battery (claimed). ADVANTAGE - The high-entropy oxide/graphene composite material has high discharge specific capacity, excellent rate performance and stable cycle performance. DETAILED DESCRIPTION - A self-supporting high-entropy oxide/graphene composite material comprises spinel structure high-entropy iron-nickel-manganese-chromium-copper oxide ((FeNiMnCrCu)3O4) uniformly provided between graphene layers. An INDEPENDENT CLAIM is included for preparation of the self-supporting high-entropy oxide/graphene composite material, which involves (S1) mixing ferric nitrate, nickel nitrate, manganese nitrate, chromium nitrate and copper nitrate to obtain a mixed salt solution, spray-pyrolyzing the mixed salt solution to obtain high-entropy iron-nickel-manganese-chromium-copper oxide, (S2) adding graphite oxide paste to water, ultrasonically dispersing, adding high-entropy iron-nickel-manganese-chromium-copper oxide, ultrasonically dispersing, freeze-drying obtained mixed solution to obtain self-supporting high-entropy oxide/graphene precursor, and (S3) sintering the self-supporting high-entropy oxide/graphene precursor in an inert gas.