ELECTROCHEMICAL ANALYSIS OF GRAPHENE NANOPARTICLE AND ACTIVATED CARBON COMPOSITE FOR FLEXIBLE ENERGY STORAGE APPLICATIONS

Abstract

This study presents the development of a foldable/rollable supercapacitor utilizing symmetrical electrode architecture. The active material comprises a composite of graphene flakes ink and activated carbon paste, with a dense metal mesh functioning as the current collector. A locally sourced “Malmal” fabric, impregnated with H₃PO₄ and PVA serves as the separator. The super-capacitive characteristics of the device, driven by a non-Faradaic charge storage mechanism, confers it with exceptional charge storage capacity and power density, rendering it highly effective for applications necessitating rapid power delivery. The device's charge-discharge dynamics were scrutinized under applied biases of 1.7 V and 1 V, both in the absence of a load and with a 1.1-ohm load resistor, over varied temporal intervals. EIS analysis was employed to elucidate the device's electrical properties, yielding Nyquist and Bode plots. The R_ESR and parallel connected Rp were determined to be 2.048 Ω and 4.312 Ω, respectively. The relatively low Rp value indicates the device's suitability for interfacing with loads exhibiting impedances lower than Rp and its potential for integration in cascaded configurations with other supercapacitors to augment overall charge storage capacity. It has been observed that the understudy fabricated supercapacitor device capacitance varies from 3.58 uF to 7.74 µF, by approximating Z[Ω] ≈ Xc in the formula , over the range of frequencies from10 mHz to 10 kHz having biasing range varies from 0.1 V to 1.7 V.