Spray-deposited SOG/MoS₂ hybrid coatings on carbon fiber electrodes for quasi-solid-state supercapacitors

Quasi-solid-state supercapacitors based on carbon fiber (CF) electrodes were fabricated using spray-deposited selectively oxidized graphene (SOG), exfoliated molybdenum disulfide (MoS₂), and hybrid SOG/MoS₂ coatings in combination with a PVA/ethylene glycol/H 3 PO 4 gel electrolyte. The study compared the electrochemical response of bare CF, single-component coatings, and the hybrid architecture under the same device configuration. Among the coated systems, the hybrid electrode delivered the most favorable electrochemical response, reaching ~121 F g −1 (91 mF cm −2 ) at 5 mV s −1 , together with the lowest series resistance (~19 Ω) and the highest output power (~3.2 mW) under the tested conditions. CV, impedance, and charge–discharge-based analyses indicate that the advantage of the hybrid coating is associated with a more favorable balance among capacitance, resistive response, and power delivery at the device level, rather than with the optimization of a single electrochemical parameter. These results show that combining SOG and MoS 2 in a spray-deposited coating on CF provides a more effective solid-state electrode architecture than the corresponding single-component coatings within the present device configuration.