In this research, we are reporting for the first time the activated carbon from amarula husks (AMH) produced by a facile two-step synthesis method producing low-cost, high porosity materials through impregnation of raw materials with water salt. The treated AMH exhibited high specific surface area with a maximum specific capacitance of 275 F g^-1 at 0.5 A g^-1 in a three-electrode arrangement. The invented symmetric device presented a peak specific capacitance of 140 F g^-1 that relates to the specific energy and power of 16 Wh kg^-1 and 450 W kg^-1 at 0.5 A g^-1. The symmetric device showed a trivial capacitance retention loss in which 5.7% noted after 13,000 cycling and 14.7% for up to 20,000 cycling at 5 A g^-1. A remarkable increase in specific energy from 15.5 to 38.3 Wh kg^-1 at 1 A g^-1 was noticed after 200 h floating time. The outcomes suggest the prospective synthesis route for converting cost-effective biomass material for developing high performing energy storage devices.