Binary MnO2/Co3O4Metal Oxides Wrapped on Superaligned Electrospun Carbon Nanofibers as Binder Free Supercapacitor Electrodes

Abstract

Increasing the performance of energy storage systems using different metal oxides and carbon nanomaterial as support scaffolds in electrode manufacture is of great importance. However, deposition of active material using binders or conductive agents results in reduced effective contact areas in the electrodes and between the electrolytes, lowering the energy storage capacity. In this work, a homogeneous and stable low current electrodeposition of binary metal oxides MnO₂/Co₃O₄ on superaligned electrospun carbon nanofibers (SA-ECNFs) greatly overcomes these shortcomings. The morphology tests revealed that the manganese oxide (MnO₂) and cobalt oxide (Co₃O₄) were uniformly wrapped around the carbon nanofibers to form a porous morphology, rendering high energy storage capacity from both the pseudocapacitance and electrochemical double layer (ECDL). Electrochemical tests indicated that the as-prepared MnO₂/Co₃O₄@SA-ECNFs electrode displays a specific capacitance of 728 F g–¹ in 6 M KOH electrolyte in CV vs 622 F g–¹ of MnO₂@SA-ECNFs electrode at 5 mV s–¹. The performance of galvanic charge–discharge (GCD) at 2 A g–¹ of the electrode demonstrated 64.5 Wh kg–¹ for energy density and 1276 W kg–¹ for power density and a capacity retention of 71.8% over 11 000 cycles.