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.