Pulse-Reversal Deposition of Nickel Sulfide Thin Film as an Efficient Cathode Material for Hybrid Supercapacitors

Abstract

In this study, nickel sulfide (Ni3S2) thin film was electrodeposited on Ni foam substrate by using a facile potentiodynamic (PD) and pulse-reversal (PR) method, respectively. After optimization of deposition parameters, the optimized Ni3S2 electrode was prepared by using PR mode under -1 V pulse-on potential, 0 V pulse-reversal potential, duty cycle of 0.5 and pulse frequency of 0.1 Hz. It delivered an impressive specific capacity up to 179.5 mAh g-1 at current density of 2 A g-1.The hybrid supercapacitor (SC) was assembled by using the optimized Ni3S2 electrode as cathode and activated carbon fiber cloth (ACFC) as anode, respectively. The Ni3S2//ACFC hybrid SC exhibited a high specific capacity of 26.7 mAh g-1 at charge-discharge current density of 2 A g-1 and displayed a maximum energy density of 26.4 Wh kg-1 at 1978 W kg-1 based on the total mass of active material of 9.2 mg. Furthermore, the Ni3S2//ACFC hybrid SC showed an impressive excellent cycling performance in 1 M KOH aqueous electrolyte at current density of 2 A g0-1, with 97% specific capacitance retained after cycling of 400-5000 consecutive charge/discharge tests.