Polythiophene/WO ₃ /Al ₂ O ₃ Ternary Nanocomposite Electrodes for High‐Performance Flexible Symmetric Supercapacitors

ABSTRACT Conducting polymers and metal oxides are crucial in the field of supercapacitors. The chemical oxidative polymerization in situ method is used to synthesize the polythiophene/WO 3 /Al 2 O 3 (PWA) ternary nanocomposites. X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), elemental mapping, energy‐dispersive x‐ray spectroscopy (EDX), high‐resolution transmission electron microscopy (HRTEM), and x‐ray photoelectron spectroscopy (XPS) are employed to confirm the morphology, structure, and elements of the synthesized materials. The electrochemical analysis of the fabricated symmetric supercapacitor (SSC) device is measured by using a potentiostat. The combination of the WO 3 /Al 2 O 3 with polythiophene (PTh) improves the performance of the PWA nanocomposite electrodes and the fabricated SSC. The specific capacitance ( C sp ) for the PWA5 nanocomposite electrode was measured as 663 F g −1 at 1 A g −1 in 1 M aqueous Na 2 SO 4 solution. The PWA5 SSC has the C sp of 446 F g −1 at 1 A g −1 using PVA–Na 2 SO 4 gel. The cyclic stability of the SSC device shows the capacitance retention of 94.4 % over the 2000 GCD cycles. The energy density and power density of PWA5 SSC is measured to be 63.18 W h kg −1 and 504.87 W kg −1 , respectively. The addition of the WO 3 /Al 2 O 3 to the PTh enhanced the overall performance of the fabricated device by improving the stability and electrical conductivity. The improved performance indicates that the PTh/WO 3 /Al 2 O 3 is a promising candidate as an energy storage system.