Fabrication of Porous Mesh‐Like FeCo2S4 Nanosheet Arrays on Ni Foam for High Performance all Solid‐State Supercapacitors and Water Splitting

Abstract

AbstractPorous mesh‐like FeCo2S4 nanosheet arrays on Ni foam (NF) have been prepared by a two‐step hydrothermal approach and employed as electrodes for supercapacitors and efficient bifunctional electrocatalysts for water splitting. FeCo2S4/NF exhibits ultrahigh areal capacitance of 7.37 F cm−2 at current density of 5 mA cm−2 and achieves good cycling stability retaining 92% capacitance after 3000 cycles at 10 mA cm−2. Symmetric solid‐state device of FeCo2S4/NF as positive and negative electrodes delivers a remarkable energy density of 19.12 W h kg−1 (434.61 W kg−1). Furthermore, FeCo2S4/NF electrode delivers a low overpotential of 155 mV at a hydrogen evolution reaction (HER) current density of 10 mA cm−2 and shows no obvious attenuation after stability test for 100,000 s in 1 M KOH solution. While a low overpotential of 234 mV at 50 mA cm−2 for oxygen evolution reaction (OER) can be demonstrated in alkaline environment as an anode electrocatalyst. FeCo2S4/NF shows excellent activity toward overall water splitting with 10 mA cm−2 by applying just 1.405 V across the two electrodes. Hence, the porous mesh‐like FeCo2S4 nanosheet arrays on Ni foam are promising electrode materials for supercapacitor application and water splitting.