Abstract

Supercapacitors are at the forefront of energy storage devices due to their ability to fulfill quick power requirements. However, safety and cost are important parameters for their real-world applications. Green materials-based electrodes and electrolytes can make them safer and cost-effective. Herein, a supercapacitor based on a methyl-grafted natural rubber/salt-based electrolyte and natural graphite (NG)-based electrodes are fabricated and characterized. Zinc trifluoromethanesulfonate [Zn(CF₃SO₃)₂] is used as the salt for the electrolyte. A mixture of NG, activated charcoal, and polyvinylidenefluoride is used for electrodes. Our supercapacitor shows a single electrode specific capacitance, C_sc of 4.2 Fg⁻¹ from impedance measurement. Moreover, the capacitive and resistive features are dominant at low and high frequencies, respectively. The cyclic voltammetry test shows the dependence of C_sc on the scan rate with a high value at slow scan rates. Performance of the supercapacitor during 5000 charge and discharge cycles at a constant current of 90 μA shows a rapid decrease of single electrode specific discharge capacitance at the beginning, but it starts to stabilize after about 2500 cycles. These findings are relevant to further developments of green materials-based supercapacitors, offering opportunities to expand the functionalities of supercapacitors in green technologies.