Biomass derived activated carbons (ACs) are promising material for supercapacitor as well as hybrid capacitor’s electrode due to their high surface area, porosity, abundant quantity and eco-friendly resource. Mostly ACs have high surface area and porosity which will enhance the capacitance, but having a low conductivity that caused by lack of graphitic structure in ACs. Then, this study was focused on upgrading the graphitization degree of ACs to increase its conductivity and investigate the effect of modification to the development of surface area and porosity of ACs.

ACs were developed from vetiver root, which massively wasted on essential oil manufacturers in Jawa Barat, Indonesia. AC synthesized via hydrothermal carbonization and followed by chemical activation using potassium hydroxide (KOH) and potassium ferrate (K₂FeO₄) as an activating agents. Chemical activation stage was variated by 1:2 and 1:4 activating agents mass ratio and at temperature of 800 and 900℃.

KOH is a suitable agent for synthesis ACs with high surface area (S_BET) with large microporosity. While K₂FeO₄ has shown a great impact in enhancing the graphitization degree and microcrystalline properties however with low surface area. Increasing each activating agent mass ratio from 1:2 to 1:4 has increased ACs's surface area but decreased the graphitization degree. Increased the activation temperature has increased graphitization degree but lowering its surface area.