Cu/graphene composite coatings electrodeposited in a directly dispersed graphene solution after electrochemical exfoliation with enhanced oxidation resistance

•Graphene is electrochemically exfoliated and directly dispersed in a CuSO4/DMF/H2O solution without adding a surfactant.•Cu/graphene composite coatings are plated in the graphene dispersions without collection and addition of graphene.•The co-deposited graphene has an effect on reducing oxidation degree of the Cu/graphene composite coatings. Directly dispersing graphene in aqueous solutions, without chemical treatment or adding surfactants, remains an obstacle for plating metal-graphene composite coatings. In this study, graphene was prepared by electrochemical exfoliation of a graphite anode and directly dispersed in N, N-dimethylformamide (DMF)/H2O solutions containing CuSO4 (40, 80, and 120 g/L) without adding a surfactant. Cu/graphene composite coatings were electrodeposited in graphene dispersions. The Cu/graphene composite coating with the highest graphene content was obtained in a solution with 80 g/L CuSO4. The co-deposited graphene affected the preferred orientation and led to a different oxidation reaction rate between the Cu/graphene composite coatings. After thermal treatment, the Cu/graphene composite coating plated in the solution with 80 g/L CuSO4 exhibited the lowest oxidation degree. This indicates that co-deposited graphene reduces the oxidation degree of Cu/graphene composite coatings.