This study describes the creation and use of composites of nickel oxide and activated carbon as supercapacitor electrodes. A one-pot reaction is used to synthesize composite materials of nickel oxide and activated carbon (microalgae, asphaltene, and wood). A precursor solution of Ni(OH) 2 is blended with activated carbon through a precipitating method at a controlled weight ratio of nickel oxide and activated carbon, then the obtained powder is calcinated at 300 C for 3 hr. The composites are analyzed by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). It is confirmed that nickel oxide sprouted on activated carbon surface. At a nickel oxide activated carbon weight ratio of 1:20, the greatest specific capacitances at 1 A/g current density are 624.2, 487.1, and 403 F/g, respectively.