Sustainable supercapacitor with a natural rubber‐based electrolyte and natural graphite‐based electrodes

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.

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