▎ 摘　　要

NOVELTY - A composite material comprises graphene material and calcium vanadate in mass ratio of 1:35-40. The composite material is sheet-like composite material. USE - Composite material used as positive electrode active material for aqueous zinc ion battery (claimed). ADVANTAGE - The composite material has excellent conductivity and electrochemical property, and improves the cycle stability, and electrochemical and rate performance of aqueous zinc ion battery. DETAILED DESCRIPTION - A composite material comprises graphene material and calcium vanadate (CaV4O9) in mass ratio of 1:35-40. The composite material is sheet-like composite material An INDEPENDENT CLAIM is included for preparation of the composite material, which involves mixing vanadium source, calcium source, graphene material and glycerol with water, subjecting to hydrothermal reaction and solid-liquid separation to obtain precursor and heat-treating precursor at 300-600 degrees C. The vanadium source is vanadium pentoxide.