Synthesis and Characterization of Reduced Graphene Oxide for Supercapacitor Application with a Biodegradable Electrolyte.

The possibility of synthesizing a proton-conducting biopolymer electrolyte of polyvinyl alcohol (PVA) doped with 1-ethyl-3-methylimidazolium ethyl sulphate ([EMIM][EtSO₄]) ionic liquid and ammonium acetate (CH₃COONH₄) by solvent casting has been investigated. The ionic conductivity of electrolyte membrane increased with addition of IL and fairly good ionic conductivity of 6.56 × 10⁻⁴ S cm⁻¹ has been attained. The conductivity studies of the biopolymer electrolyte membrane have been carried out in coplanar configuration. Graphene oxide (GO) and reduced graphene oxide (rGO) have been synthesized by a chemical method. The prepared rGO has been characterized using ultraviolet–visible (UV–Vis) absorption spectroscopy, x-ray diffraction, Raman and x-ray photoelectron spectroscopy analysis. The surface area of rGO has been increased from 2.69 m² g⁻¹ to 203.78 m² g⁻¹. In this work, a supercapacitor with a symmetric electrode has been fabricated using PVA-doped ionic liquid as a biopolymer electrolyte and rGO as electrode materials. Its electrochemical performance has been verified, and the device exhibited a good specific capacitance of 138 F g⁻¹. This combination was found to be very useful to improve the capacitance of supercapacitor. [ABSTRACT FROM AUTHOR]