Enhancement of supercapacitance of reduced graphene oxide, copper oxide and polyaniline using the mixture of methane sulphonic acid and sulphuric acid as electrolyte

Abstract

The mixture of mineral acid and organic acid as aqueous electrolyte for the rGO12%: Cu<inf>2</inf>O/CuO40%: PANI48% (G12CP) nanocomposite, exhibited superior energy storage performance. The acid mixture electrolyte used is 0.4 M H<inf>2</inf>SO<inf>4</inf> + 0.4 M CH<inf>3</inf>SO<inf>3</inf>H (1:1) (SA + MSA) and it exhibited enhanced diffusion and kinetic features in comparison with the bare 0.4 M H<inf>2</inf>SO<inf>4</inf> (SA) and 0.4 M CH<inf>3</inf>SO<inf>3</inf>H (MSA). SA + MSA provided 16.8% higher energy storage than the SA and the performance obtained after 5000 charge/discharge cycles is 276.98% higher than the performance obtained before the cyclic stability test using the same acid mixture electrolyte. The G12CP provided a specific capacitance (C<inf>s</inf>) of 490.19 F g?1, an energy density (E) of 98.0392 W h kg--1 and a power density (P) of 1.500l kW kg?1 at 1 A g?1 in the presence of SA + MSA. The obtained E is comparable with E of Li-ion batteries, Ni-metal hydride batteries, Na-S batteries, and Na-metal chloride batteries. © 2020 Elsevier Ltd