AbstractIn present investigation, we have prepared a nanocomposites of highly porous MnO₂ spongy balls and multi-walled carbon nanotubes (MWCNTs) in thin film form and tested in novel redox-active electrolyte (K₃[Fe(CN)₆] doped aqueous Na₂SO₄) for supercapacitor application. Briefly, MWCNTs were deposited on stainless steel substrate by “dip and dry” method followed by electrodeposition of MnO₂ spongy balls. Further, the supercapacitive properties of these hybrid thin films were evaluated in hybrid electrolyte ((K₃[Fe(CN)₆ doped aqueous Na₂SO₄). Thus, this is the first proof-of-design where redox-active electrolyte is applied to MWCNTs/MnO₂ hybrid thin films. Impressively, the MWCNTs/MnO₂ hybrid film showed a significant improvement in electrochemical performance with maximum specific capacitance of 1012 Fg⁻¹ at 2 mA cm⁻² current density in redox-active electrolyte, which is 1.5-fold higher than that of conventional electrolyte (Na₂SO₄). Further, asymmetric capacitor based on MWCNTs/MnO₂ hybrid film as positive and Fe₂O₃ thin film as negative electrode was fabricated and tested in redox-active electrolytes. Strikingly, MWCNTs/MnO₂//Fe₂O₃ asymmetric cell showed an excellent supercapacitive performance with maximum specific capacitance of 226 Fg⁻¹ and specific energy of 54.39 Wh kg⁻¹ at specific power of 667 Wkg⁻¹. Strikingly, actual practical demonstration shows lightning of 567 red LEDs suggesting “ready-to sell” product for industries.