Hydrothermal strategy was used to grow molybdenum sulfide (MoS2) micro flower-like structures reinforced reduced graphene oxide (rGO) for supercapacitor (SC) application. Morphological and structural analyses confirmed the well-distribution of MoS2 on rGO sheets. Despite using lithium sulfate (Li2SO4) as a relatively high-voltage window electrolyte, potassium iodide (KI) was incorporated for sturdy iodide/iodine redox interaction. Thus, the fabricated symmetric SCs result achieved superior power density (Pd) of ∼36 kW/kg and exceptionally high energy density (Ed) of 132.9 Wh/kg at 10 and 0.1 A/g, respectively. The maximum estimated specific capacitance (Cs) was 357 F/g for optimum KI ratio. Additionally, SC possesses more than 99 % of retention value after applying 8000 cycles at 10 A/g. These findings implies MoS2/rGO composite and Li2SO4/KI mixed electrolyte configuration as a simple but efficient SC configuration for high energy, power and lifetime.