Activated carbons from KOH-activation of argan (Argania spinosa) seed shells as supercapacitor electrodes

► Activated carbons were prepared by KOH-activation of ASS. ► Activated carbons with surface area as high as 2100 m2/g were obtained. ► The highest capacitance was 355 F/g at 125 mA/g and with a 93% retention at 1 A/g. ► ASS is an excellent biomass precursor to prepare activated carbons for EDLC uses.