A hydroquinone mediated PVA–H₂SO₄ gel electrolyte (PHHQ) and activated carbon from bio-waste were prepared for supercapacitor fabrication. PHHQ delivered a higher capacitance (941 F g⁻¹ at 1 mA cm⁻²) and energy density (20 Wh kg⁻¹ at 0.33 W g⁻¹) than the PVA–H₂SO₄ gel electrolyte (425 F g⁻¹ at 1 mA cm⁻², 9 Wh kg⁻¹ at 0.33 W g⁻¹).