Designing of BiFe2O3@NiCoS@rGO nanocomposite electrode: A versatile platform for high-performance energy storage and electrolyte SIW/AN

A comprehensive investigation of new materials and compositional modifications has made high-performance hybrid supercapacitor electrodes. This work mainly focuses on the synthesis of nickel cobalt sulfide (NiCoS) by hydrothermal methods and then adding bismuth ferrite (BiFe₂O₃) and the measurement of the electrochemical properties. The "salt in water" (SIW) solutions, which are super-concentrated aqueous electrolytes, enable a significant reduction in water activity and increase the electrochemical stability window, is utilized. The electrochemical analysis is performed using the two and three-electrode systems. The BiFe₂O₃@NiCoS@rGO electrode attained a noteworthy maximum capacity (Qs) of 393.7 mAhg⁻¹ in a three-electrode assembly. The BiFe₂O₃@NiCoS@rGO//A.C showed a considerable Qs of 52.3 mAh/g, an improved energy density (E_d) of 79.2 W h kg⁻¹, and a high power density (P_d) of 2.2 kW kg⁻¹ in two electrode systems. The device has undergone extensive testing, with up to 5000 cycles, and has demonstrated an exceptional capacity retention rate of 88.2 %. Based on these intriguing findings, the BiFe₂O₃@NiCoS@rGO nano-composite displays immense promise for developing electrodes in advanced hybrid supercapacitors.