Noval synthesis of systematized FeS/CuO nanostructure efficacious electrode material for escalating asymmetric supercapacitors

Abstract

FeS and CuO have snatched much intentness because of proper electrochemical achievements as supercapacitor electrode materials. Nevertheless, the merits of CuO are constricted by below-standard cyclic stability and conductivity. At the same time, FeS exposes laudable theoretical capacity and sustainable electrical conductivity, thus making them suitable candidates as composite electrodes. Recently, biomass-produced carbon composites incorporated with CuO nanoparticles have been introduced for utilizing inexpensive carbon source from peanut shells and the CuO precursor is copper acetate. The Faraday capacitance contributed by the CuO nanoparticles and the synergistic effect of double-layer capacitance from porous carbon was successfully realized, resulting CuO-AC electrode with elevated specific capacitance of 530 Fg^-1 at 1 Ag^-1. Herein, FeS/CuO composite with two different ratios i.e. FeS/CuO (1:1) as FC-1, FeS/CuO (4:6) as FC-2 are fabricated by hydrothermal synthesis and ball milling for electrode material in supercapacitor. The composite FC-2 possesses a commendable specific capacitance of 833 Fg^-1 at 1 Ag^-1 in the three-electrode and 180 Fg^-1 in two-electrode ASC, higher than those of FC-1, FeS, and CuO electrodes. Moreover, the electrode exhibits a capacitance retention of 81% at current density of 1 Ag⁻¹ during 500 consecutive charge-discharge cycles, much higher than 40 % of FC-1, the increased specific capacitance of FC-2 electrode is attributed to the synergistic interaction between Fe⁺² and Cu⁺², collectively with the cauliflower-like morphology of CuO, which offers large surface area for the FeS nanoplates, hence enhancing the conductivity process, thus putting high expediency of composite FC-2 electrode in the electrochemical capacitors. The current synthetic approach is efficient and economical, and can be adapted for the synthesis of further sulfide-based transition metal oxides exhibiting superior electrochemical characteristics for energy preservation and transformation.