Unveiling the energy storage potential of valorized unripe plantain peel-derived activated carbon

Abstract The damage from excess waste generation on the environment has made it necessary to re-think how we approach product development and the waste management lifecycle. Within this framework, conversion of biowaste into energy storage materials has emerged as an effective means of reducing the environmental impact of food production. In this work, activated carbon with superior supercapacitive properties is produced directly from unripe plantain peel by optimizing the use of two different activating agents KOH and ZnCl 2 during pyrolysis. Activated carbon Z7 which was pyrolyzed at 700 °C using ZnCl 2 as the activating agent had a higher surface area of 1636 m 2 /g and higher electrochemical performance when compared to activated carbon produced under all other experimental conditions. The specific capacitance obtained for Z7 in a two-electrode Swagelok set-up was 167 F g −1 at 0.5 A/g and an excellent energy density of 23 Wh/kg at a power density of 174 W/kg at 0.5 A/g current was obtained. Further-more, a capacitance retention of 79% was achieved after 4500 cycles at a current density of 5 A/g with a coulombic efficiency of 99%.