Synthesis of rGO/TiO 2 /PEDOT nanocomposites, supercapacitor device performances and equivalent electrical circuit models

Abstract

A new nanocomposite electrode incorporating poly(3,4-ethylenedioxythiophene) (PEDOT) within the nanocomposite film of the reduced graphene oxide / Titanium dioxide (TiO₂) was synthesized to be used in supercapacitor devices. We used constant EDOT monomer for in-situ polymerization and different initial monomer concentration ratio of [rGO]_o/[TiO₂]_o = 1/1, ½ and 1/5. The obtained nanocomposites were examined by FTIR-ATR, UV-vis, SEM-EDX, TGA-DTA, BET surface areas and pore distribution, XRD, TEM, AFM, CV, GCD and EIS analyses. The results showed that graphene oxide was successfully reduced to rGO by means of the microwave-assisted method. It was confirmed by the increases in the specific capacitance of (C_sp = 652 F/g) at 1 mV/s for the rGO/TiO₂/PEDOT nanocomposite at [rGO]_o/[TiO₂]_o = 1/5. This was related to the pore size (~33.50 nm) of the material for rGO/TiO₂/PEDOT at [rGO]_o/[TiO₂]_o = 1/5 obtained from BET analysis. The other C_sp values were 475.33 F/g for [rGO]_o/[TiO₂]_o = 1/2, 114.09 F/g for rGO/PEDOT and 48.02 F/g for [rGO]_o/[TiO₂]_o = 1/1. Equivalent circuit model of R_ct(C_dlR_ct) was analyzed via ZSimpWin and TINA programmes. A facile and inexpensive approach for a ternary nanocomposite synthesis of rGO/TiO₂/PEDOT was presented for future supercapacitor applications.

Graphical abstract

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