Synthesis of graphene via electrochemical exfoliation in different electrolytes for direct electrodeposition of a Cu/graphene composite coating

Directly dispersing graphene into an electrolyte still remains a crucial difficulty in electrodepositing a graphene enhanced composite coating onto electrical contact materials. Herein, graphene was synthesized via electrochemical exfoliation in an N,N-dimethylformamide (DMF)/H(2)O solution containing (NH(4))(2)SO(4). The electrochemically exfoliated graphene nanosheets (GNs) were directly dispersed by sonication. In comparison with graphene synthesized from aqueous solution, the GNs electrochemically exfoliated in the DMF/H(2)O–(NH(4))(2)SO(4) solution exhibit a lower degree of oxidation. Cu/graphene composite coatings were subsequently electrodeposited onto Cu foils by adding Cu(2+) into the as-fabricated graphene solution. The surface nanostructure of the Cu/graphene composite coatings was transformed from loose pine needles to a uniform and compact structure with an increase in the concentration of Cu(2+), which indicated that the controllable synthesis of Cu/graphene composite coatings with different performances could be achieved in graphene dispersions after adding Cu(2+). In order to synthesize graphene via electrochemical exfoliation and directly electrodeposit a Cu/graphene composite coating without adding CuSO(4) or any other additive, an attempt was made to directly electrodeposit a Cu/graphene composite coating in CuSO(4)/DMF/H(2)O solution after electrochemical exfoliation.