Synthesis of activated carbon from bamboo biomass for supercapacitor electrodes with various types of electrolytes

One of the potential biomass as a carbon raw material is bamboo. Bamboo is a rich source of biomass in Indonesia. Supercapacitor electrodes derived from bamboo biomass as an active carbon material have high power and energy capabilities due to their high surface area and high conductivity. This study focused on the process of synthesizing bamboo-based activated carbon using a hydrothermal carbonization process in which he uses ZnCl2 as the activator. The mass ratio of materials, activating agent, solvent is 1:2:3. The reaction in hydrothermal carbonization was performed at 275°C for 1 hour. Additionally, the hydrochar were activated in the presence of CO2 at a temperature of 800 °C for 2 hours. Activated carbon is used as electrodes in supercapacitors. The activated carbon obtained in this study was then characterized physically, consisting of adsorption/desorption isotherms to measure total spesific surface area by the Brunauer-Emmet-Teller (BET) calculation method. BET analysis showed that the pore size ranged from 1.59-8.99 nm, and the specific surface area decreased from 469.374 m2/g for ACB non-deashing to 453.764 m2/g for ACB with deashing. Furthermore, the physical characterizations and electrochemical characterization show that pre-treatment with deashing affects the performance of the supercapacitor. The assembled symmetric ACB non-deashing and ACB deashing supercapacitor using 6M KOH electrolyte device delivered the highest specific capacitance of 32.11 F/g and 24.79 F/g at scan rate 2 mV/s. As well, the value of specific capacitance for ACB non-deashing and ACB deashing supercapacitor using 1M Na2SO4 electrolyte is 32.07 F/g and 13.08 F/g at scan rate 2 mV/s. Cyclic stability tests conducted for ACB non-deashing supercapacitor in 6M KOH electrolyte by charge-discharge cycles were approached 99% indicated the capacitance retention (CR) with 100% coulombic efficiency (CE) over 10 cycles. Based on this study's findings, pre-treatment with deashing on bamboo raw material with aqueous electrolyte can provide different performance characteristics of supercapacitors.