This work explores the synergistic advantage of the lignocellulose chemistry of oil palm fiber, empty fruit bunch, and oil palm shell as a composite in activated carbon preparation using physical and chemical activation methods. Using coin cell CR2032�3 V, supercapacitors were fabricated with the prepared activated carbon composite as electrode active material and H3PO4-based gel electrolyte. At a specific power density of 50 WKg�1, electric double-layer capacitors derived from chemically and physically activated carbon composite shows a specific energy density of 8.6 WhKg�1 and 5.8 WhKg�1, respectively. These results were observed to be better than the results of supercapacitors fabricated using liquid electrolytes. Apart from the better performance, the solid-state electric double layer capacitor is relatively lighter, allows miniaturization, flexibility, and mitigates liquid electrolyte leakage. © 2021 Elsevier Ltd