Performance enhancement of Li-ion batteries by the addition of metal oxides (CuO, Co3O4)/solvothermally reduced graphene oxide composites

Solvothermally reduced graphene oxide (STRG) that was synthesized using N-methyl-2-pyrrolidone (NMP) solvent was first employed as an conducting additive up to 15 wt% to commercial graphite anodic material. Due to numerous functional groups on the surface of the STRG, the reversible capacity decreased as the amount of STRG in the anode increased. To overcome this disadvantage, nanosized metal oxides such as CuO and Co3O4 were supported on the STRG and a small amount of the composites was added to commercial graphite in order to enhance cyclic performance of the anode. A variety of characterization techniques showed that the composite additive significantly increased the reversible cyclic capacity by reducing the irreversible capacity of STRG and by providing more space for lithium ion intercalation.