Effective conversion of waste banana bract into porous carbon electrode for supercapacitor energy storage applications

Herein, high capacitive supercapacitor performance of porous carbon electrode material obtained from waste banana bract was created by two-step chemical activation using KOH. Based on the findings of the structural analysis, the effective pore size contribution to the electrochemical performance in a neutral electrolyte (1M Na2SO4) was examined using cyclic voltammetry, galvanostatic and electrochemical impedance spectroscopy techniques on porous carbon samples activated at temperatures between 500 and 800°C and exhibiting Brunauer–Emmett–Teller surface areas ranging from 22.9 to 513 m2g−1. The highest specific capacitance of 472 Fg−1 was obtained by the typical rectangular CV profile in the potential window range of -0.2 to +1 V for 800 °C. At 1 Ag−1, the high energy density of 86 Whkg−1 at 1.28 kWkg−1 of power density was reached with the capacitance retention of 93.5% at 5000 cycles at 10 Ag−1. These findings demonstrate the viability of using porous carbon from waste bracts in high-performance supercapacitors.