NiF2 as an efficient electrode material with high window potential of 1.8 V for high energy and power density asymmetric supercapacitor

Abstract

We investigated NiF 2 as an energy storage material in asymmetric supercapacitor together with activated carbon (AC) as the counter electrode. Cyclic voltammetry and galvanostatic charge-discharge profile are carried out to investigate the oxidation-reduction process and capacitive behavior of the NiF 2 sample. The interfacial electron transport properties of the sample are also explored using Nyquist plots in two and three electrodes configurations of electrochemical impedance spectroscopy. A very high specific capacitance of 751 F/g is achieved at 1 A/g current density in three electrode system. Further, the asymmetric supercapacitor device based on NiF 2 //AC structure reveals high capacitance of 175 F/g at 1 A/g in the high window potential of 1.8 V. The fabricated device retained 93% of its initial capacitance after 1000 cycles at 3 A/g current density affirms high electrochemical stability of the device. Ragone plot depicts high energy density of 79.65 Wh/kg with power density of 1727.35 W/kg for 1.8 V window potential at 1 A/g current density. High electrochemical stability of NiF 2 sample endures the tetragonal phase even after electrochemical measurement which can be more useful in recycling the electrode material for future recycled supercapacitor devices. • Pristine NiF 2 was employed for the fabrication of asymmetric supercapacitor device. • NiF 2 //AC device presented high C s of 175 F/g@1 A/g with high window potential of 1.8 V. • Ragone plot depicts high E D = 79.65 Wh/kg and P D = 1727.35 W/kg for 1.8 V@1A/g. • After electrochemical measurement, NiF 2 can be recyclable for further device fabrication.