Chemical synthesis of polyaniline and polythiophene electrodes with excellent performance in supercapacitors

The emergence of portable electronics in miniaturized and intelligent devices demands high-performance supercapacitors (SC) and batteries as power sources. For the fabrication of such energy storage devices, conducting polymers (CPs) have significant advantages due to their high theoretical capacitive performance and conductivity. In this work, we developed two CPs including polyaniline and polythiophene through a low-cost chemically synthesized approach and the film-by-spin coating method. The structural and morphological properties of the CPs are analyzed using Fourier-transform infrared spectroscopy (FTIR), contact angle measurement, and scanning electron microscopy (SEM). Based on these CPs, novel pristine polyaniline and polythiophene-based SCs (PASC and PTSC) are developed. The prepared CPs contribute to high electrochemical performances due to their high conductive nature of the electrode and conjugated polymer materials reaction. Hence both electrochemical double-layer formation and pseudocapacitance contributed to the energy-storing performances of the device. Electrochemical impedance spectroscopic analysis (0.1 Hz to 100 kHz) demonstrates faster ionic exchange and high capacitance of the PASC electrode as compared to PTSC in H3PO4 electrolyte. The PASC devices exhibit specific capacitance of 13.22 mF·cm−2 with energy and power densities of 1.175 μW·h·cm−2 and 4.99 μW·cm−2 at a current of 50 μA. Compared to PTSC (specific capacitance 3.30 mF·cm−2) the PASC shows four times higher specific capacitance due to its improved surface, structural and electrical properties. The electrochemical performance reveals the superior SC performance for this type of CP electrode.