Unleashing Enhanced Energy Density with PANI/NiO/Graphene Nanocomposite in a Symmetric Supercapacitor Device, Powered by the Hybrid PVA/Na2SO4 Electrolyte.

In this study, a PANI/NiO/Graphene (PNG) nanocomposite was synthesized using a cost-effective wet chemical polymerization method. This nanocomposite was used to fabricate supercapacitor electrodes in a nontoxic, noncorrosive, and neutral hybrid gel polymer (PVA/Na2SO4) electrolyte. The electrodes made from the PNG material underwent analysis using electrochemical techniques, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy in a three-electrode system. For a deeper exploration of the supercapacitive properties of the PNG material, galvanostatic charge-discharge was employed. A practical two-electrode symmetric device powered by the hybrid PVA/Na2SO4 electrolyte was fabricated to calculate specific capacitance, energy density, and power density. The designed PNG material demonstrates excellent electrochemical behavior, exhibiting an improved energy density of 59.41 W h/kg at 850 W/kg. Furthermore, the PNG electrode shows excellent reversibility along with enhanced energy density and retains 89% of its capacitance after 2000 cycles. These outstanding properties of the PNG material can be attributed to the synergistic effect of PANI nanofibrous, NiO, and graphene two-dimensional structures.