Oxidative calcination of brewery bagasse and in-situ preparation of activated carbon-PEDOT composite for hybrid supercapacitor application

In this study, we prepared an electrode material from biowaste residue for hybrid supercapacitor application. Bagasse from brewery residue was treated by oxidative calcination at 300 °C. The carbonized material was impregnated using different concentrations of potassium hydroxide (KOH), followed by thermal annealing at 850 °C to obtain activated carbon (AC). The AC obtained was used to prepare a composite with poly(3,4-ethylenedioxythiophene) (PEDOT) via in-situ polymerization process using iron (III) tosylate as oxidizing agent. Pure activated carbon attained a specific surface area (SSA) of 625 m² g⁻¹, and specific capacitance of 80.38 F g⁻¹ at 5 mV s⁻¹ while the AC-PEDOT composite presents 201 F g⁻¹ at the same scan rate, given about 250 % improvement to the specific capacitance. Likewise, the AC presented an energy density of 10.88 Wh Kg⁻¹ and a power density of 9411.59 W Kg⁻¹ at 0.5 A g⁻¹ while the AC-PEDOT composite showed energy density of 25.92 Wh Kg⁻¹ and power density of 4836.44 W Kg⁻¹ at 0.5 A g⁻¹. The results confirm the properties of AC as a supercapacitive material and a battery-like behavior for the AC-PEDOT composite, demonstrating potential for hybrid supercapacitors application.