In‐Situ Colloidal Synthetic Route to Monodispersed NiCo₂S₄ Nanoparticles over Nickel Foam for High‐Performance Supercapacitive Charge Storage

Abstract

One‐step colloidal synthetic route was adopted to in‐situ grow monodispersed NiCo2S4 nanoparticles (NPs) on nickel foam (NF) from metallic salts with benzyl disulfide in the media of oleylamine and octadecene. Owing to the favorable dispersion and considerable redox activity of NiCo2S4 along with tight and bind‐free connection with NF, the obtained battery‐type supercapacitor delivered a specific capacitance of 1790.8 F g−1 at 1 A g−1 via a three‐electrode system. Simultaneously, it just degraded 40% at 20 A g−1 and maintained 86.8% of initial specific capacitance (C0) after 2000 cyclic trials at 10 A g−1. When the NiCo2S4 NPs were assembled with active carbon (AC) forming an asymmetric capacitor device of NiCo2S4 NPs//AC, it delivered an energy density (E) of 48.7 W h kg−1 at a power density (P) of 161.1 W kg−1, and kept 21.9 W h kg−1 at a high P of 8.05 kW kg−1. Meanwhile, the capacitor manifested preeminent cycling life (C = 94.5% C0 after 5000 cyclic trials) at 5 A g−1. The in‐situ grown NiCo2S4 NPs on NF without any binder exhibited high performance in energy storage, providing a feasible way to improve the electrochemical performance of the electrode materials.