Electrochemical performance of Mn₃O₄/graphene composite deposited on nickel foam as promising electrode material for supercapacitor application

The supercapacitor energy storage system has achieved a great attention, in future perspective, as compared to ordinary dielectric capacitors and batteries. The nature and type of electrode material employed in supercapacitor applications is critical to the electrochemical performance of a supercapacitor. Herein, co-precipitation derived Mn3O4 nanoparticles were mixed with graphite in a simple way and obtained uniformly mixed composite of exfoliated graphene with these nanoparticles. The electrochemical study of these composites revealed promising results for supercapacitor applications. X-ray diffraction study revealed the formation of single-phase Mn3O4 nanoparticles. The composite was probed for microstructural examination, by scanning electron microscopy, which revealed that Mn3O4 was uniformly embedded in exfoliated graphene sheets, aimed specifically for better electrochemical performance. The elemental composition was studied by energy dispersive X-rays spectroscopy and electrochemical performance of the composite deposited on Nickel foam for electrode using polyvinyl alcohol (PVA, 10%) as a binder has been examined by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy in 1M K2SO4 electrolyte. In addition, different ratios of Mn3O4/graphene were prepared to investigate composition dependent performance of these composites. The highest value of specific capacitance achieved for composition (1:2) was 334 F/g at scan rate of 5 mVs(-1).