Design and preparation of NiCoS nanostructures on Ni foam for high-performance asymmetric supercapacitor application

Supercapacitors are progressively being utilized for storage systems in sustainable nanotechnologies. A NiCoS nanostructure was synthesized on nickel foam by an in situ one-pot hydrothermal method at different reaction temperatures (80, 100, and 120 °C) keeping other reaction parameters such as pH and reaction time constant for supercapacitor applications. The SEM report revealed a plate-like nanostructures of NiCoS on nickel foam (NiCoS/NF). The electrode prepared at 100 °C exhibits better electrochemical activities compared to electrodes prepared at 80 and 120 °C. The integrated binder-free NiCoS/NF electrode for supercapacitor, optimized at 100 °C, manifested a large specific capacitance of 3309 mF cm−2 at a current density of 1 mA cm−2 with a notable rate capability of 427 mF cm−2 even at 10 mA cm−2. The asymmetric supercapacitor fabricated with optimized NiCoS/NF prepared at 100 °C exhibited an exceptionally high energy density of 2.04 mW h cm−3 at a power density of 42.64 mW cm−3.