Chemically deposited reduced graphene oxide/polypyrrole (rGO/Ppy) composite thin films for flexible solid-state supercapacitor: Effect of rGO composition

Abstract

As electrochemical energy storage systems become more prevalent, there is a growing imperative to investigate electrode materials that offer both flexibility and superior capacitive performance. In this research, a stainless steel substrate was used to synthesize a composite of reduced graphene oxide/polypyrrole (rGO/Ppy) by simple successive ionic layer adsorption and reaction (SILAR) method. The various rGO concentrations were used to improve the material electrochemical characteristics. Field emission scanning electron microscopy images revealed that Ppy particles were sandwiched between rGO sheets. At a 1 mg mL⁻¹ of rGO concentration, the highest specific capacitance of rGO/Ppy composite was 803 F g⁻¹, greater than Ppy (331 F g⁻¹). The rGO/Ppy composite exhibited remarkable cycling stability, retaining over 92 % of its initial capacitance over 5,000 cycles. Furthermore, rGO/Ppy/PVA-H₂SO₄/WO₃ flexible solid- state supercapacitor device revealed a specific capacitance of 49 F g⁻¹ at 5 mV s⁻¹ scan rate and showed a maximum specific energy (S_E) of 12 Wh kg⁻¹ at a 881 W kg⁻¹ specific power (S_P). This indicates that the optimized concentration of rGO in Ppy composite led to an improvement in capacitive performance, and SILAR proved to be an effective method for preparing composite electrodes.