Transition metal oxide and graphene nanocomposites for high-performance electrochemical capacitors

Abstract

A method for producing nanocomposites of transition metal oxides A₃O₄ (where A represents Mn, Fe or Co) and graphene nanosheets (GNS) is presented. The reduction of graphene oxide (GO) and the formation of A₃O₄ nanoparticles (NPs) were carried out simultaneously during the reaction. The electrochemical properties of A₃O₄–GNS nanocomposites as electrode materials for supercapacitors are investigated by cyclic voltammetry and galvanostatic charge–discharge tests. The as-prepared Mn₃O₄–GNS, Fe₃O₄–GNS and Co₃O₄–GNS nanocomposites exhibit large specific capacitance (708, 358 and 240 F g⁻¹, respectively), high energy density (20, 10 and 7 W h kg⁻¹, respectively) and good electrochemical stability (retention of 73%, 67.8% and 95.8%, respectively, after 1000 charge–discharge cycles). The excellent electrochemical performance of the A₃O₄–graphene nanocomposites indicates great potential in the application in commercial supercapacitors.