Electrodeposited Graphene/Silver/Titanium Dioxide Ternary Composites for Supercapacitor Applications

Lee, Jia Hao (2022) Electrodeposited Graphene/Silver/Titanium Dioxide Ternary Composites for Supercapacitor Applications. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Supercapacitor (SC) with ternary hybrid composite as electrodes has become prevalent for the improvement in overall electrochemical performance as an electrochemical energy storage system. In this project, a novel ternary composite of highly pure graphene, titanium dioxide and silver (Gr/TiO2/Ag) was prepared on a Cu substrate via a facile electrochemical deposition approach. Highly pure graphene with O/C ratio of 0.012 applied in the composite electrode was obtained by simple electrochemical exfoliation process with an average yield of 40% each time. Field Emission Scanning Electron Microscopy (FESEM) showed Ag nanodendrites along with TiO2 nanoparticles on the thin exfoliated graphene with few to single of corrugated and folded layers. The elemental constituents of electrodeposited ternary composites were confirmed by Energy Dispersive X-Ray (EDX) and X-ray Diffraction (XRD). The electrochemical evaluation of ternary composites in 1 M NaOH exhibited a specific capacitance of 343.79 F/g at a scan rate of 25 mV/s with pseudocapacitive behaviour. A great enhancement of 235% in specific capacitance of the Gr/TiO2/Ag ternary electrode when compared to Ag individual electrode. Ternary composite Gr/TiO2/Ag showed the least impedance in the electrochemical impedance spectroscopy (EIS) among the binary composites and individual element. The improved electrochemical performance of ternary composite electrode was resulted from the synergistic effect of the three elements specifically the highly conductive low-oxidized graphene in which was nearly similar to the pristine graphene. These results demonstrated that Gr/TiO2/Ag as ternary hybrid composite electrode will be a promising active electrode material for supercapacitor application.