Preparation of activated carbon derived from oil palm empty fruit bunches and its modification by nitrogen doping for supercapacitors

Activated carbon (AC) is one of the most promising active materials for high-performance supercapacitors (SCs) owing to its high specific surface area and theoretical specific capacity. In this study, oil palm empty fruit bunches (EFBs), which are agricultural residue, are employed as a precursor to produce AC using a series of cleaning, carbonization, and chemical activation processes. The as-produced AC has a specific surface area of 2774 m2/g, which is very high among AC produced from biomass materials. To enhance the performance of SCs, the AC is modified by nitrogen doping. The specific capacities of AC and nitrogen-doped AC are found to be 182 to 217 F/g, respectively, at a current density of 0.5 A/g in 6 M KOH aqueous electrolyte. We demonstrate that agricultural waste can be processed into AC with a high specific surface area for SC applications.