ZnCl2-assisted synthesis of coffee bean bagasse-based activated carbon as a stable material for high-performance supercapacitors

ZnCl2 activator is a hydrating reagent that works effectively to facilitate the formation of pores in the carbon matrix and this activation method is very simple with low cost. Therefore, this study aims to synthesize carbon-based materials from coffee bean bagasse (CBB) using the chemical activator ZnCl2. The optimization of the ZnCl2 impregnation process was carried out by varying the molarity in 0.1, 0.2, and 0.3 M at 80 ℃ for 2 h. Electrochemical test results showed that CBB provided a maximum specific capacitance of 250 F/g at a scan rate of 1 mVs−1 in a 1 M H2SO4 electrolyte solution at a voltage of 1 V. This high value is due to the significant irregularity associated with good conductivity and increased wettability of the electrolyte. Therefore, the results provide an evident, simple, and relevant synthesis strategy for the sustainable large-scale conversion of waste biomass into carbon materials for supercapacitor energy storage applications.