Applications of binary and quaternary thiospinel structures as electrode materials in supercapacitors

In this thesis, binary (A3S4) and quaternary (ABCS4) transition-metal thiospinels were developed for high-performance supercapacitor applications, and these materials were directly synthesized on reduced graphene hydrogel/nickel foam (RGH/NF) current collectors via a binder-free hydrothermal method. The structural properties of the synthesized electrodes were characterized using XRD, SEM, TEM, XPS, BET, and EDS analyses, while their electrochemical performance was evaluated through CV, GCD, and EIS measurements. The porous architecture and high conductivity of RGH/NF enabled rapid ion diffusion and efficient charge transfer at the electrode-electrolyte interface. Among the investigated materials, multicomponent thiospinels such as ZnMnCoS4, FeNiCoS4, and MnNiCoS4 exhibited superior specific capacitance and energy density owing to their high active surface area and enhanced redox activity. Overall, the findings demonstrate that transition-metal sulfides are promising, cost-effective, stable, and high-performance electrode materials for next-generation supercapacitor systems.