A dual-purpose binder-free FeNiS₂-Decorated Ti₃C₂T_x nanocomposite for supercapacitor and catalytic hydrogen evolution reaction

This study is focused on developing novel electrode material, FeNi-based sulfide nanoparticles (FNS) incorporated onto titanium carbide (Ti₃C₂T_x, TC, MXene) deposited on Ni foam (NF), termed as FNS@NF/TC, for energy conversion and storage application. This nanocomposite offers an improved conductivity, and stability for electrocatalytic hydrogen evolution reaction (HER) and electrochemical capacitor applications. This FNS@NF/TC nanostructured electrode is fabricated by using a binder-free technique, which is simple electrochemical deposition. The fabricated electrode shows a higher specific capacitance of 1460 F/g at the current density of 2 A/g with capacitance retention of 91.8 % and coulombic efficiency of 92 % after 5000 cycles. In the case of electrocatalytic water splitting HER, the lower overpotential is calculated at around 104 mV at the current density of 10 mA/cm² and decreased Tafel slope of around 65 mV/dec for the FNS@NF/TC nanostructured electrode with good stability after 12 h in chronopotentiometry technique. Overall, the deposition of FeNiS₂ on the Ti₃C₂T_x@NF composite enhances ion transport and storage capacity, positioning it as an up-and-coming candidate for efficient and sustainable energy conversion and storage solutions in the energy sector.