Effects of Redox - Additives and Optimising the Concentration in Aqueous Electrolytes for Increased Capacitance

ZnWO 4 nanoparticles were synthesised via facile coprecipitation technique and confirmed via X-ray diffractogram with Rietveld refinement ( χ = 1.7), Raman spectroscopy and electron microscopy. The prepared ZnWO 4 was electrochemically evaluated in alkaline electrolyte (KOH) with varying concentrations of redox additive (KI). Our results pronounced 10% KI as optimum yielding specific capacitance as 138 Fg −1 at 1 A g −1 . Further, Dunn’s analysis confirms that KI enhances the diffusion-controlled faradaic contribution, which is due to the redox activity in electrolytes due to I − /I 3 − . Also our results pronounced that KI concentration beyond the optimum concentration produce decreased specific capacitance.