Fabrication of <scp>PANI</scp>/<scp>TRGO</scp>‐<scp>MnO₂</scp> Hybrid as Working Electrode for Electrochemical Capacitor Using Thermal–Chemical Technique

ABSTRACT In this project, efficient polyaniline/thermally reduced graphene oxide–manganese oxide (PANI/TRGO‐MnO 2 ) hybrid is synthesized by thermal–chemical technique and applied as working electrode materials. The properties of the pure PANI, TRGO‐MnO 2 , and PANI/TRGO‐MnO 2 hybrids are characterized via field emission scanning electron microscopy (FESEM), X‐ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, and UV–visible spectroscopy. The fibrous PANI particles are grown on both sides of TRGO‐MnO 2 , and MnO 2 nanoparticles (NPs) are uniformly diffused in TRGO. Raman results show that the average size of the graphene crystallites (La) is obtained at 17.8 and 27.4 nm for TRGO‐MnO 2 and PANI/TRGO‐MnO 2 hybrids, respectively. The electrochemical properties of the as‐prepared electrodes are evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy, and galvanostatic charge–discharge. The CV plots illustrate that the responses of the PANI/TRGO‐MnO 2 hybrid are similar to a pseudocapacitive behavior without polarization. The results show that the prepared PANI/TRGO‐MnO 2 hybrid indicates greatly improved specific capacitance of 1027.27 F.g −1 as compared to pure PANI (581.05 F.g −1 ) and TRGO‐MnO 2 (791.39 F.g −1 ) in 1 molar sulfuric acid (1 M H 2 SO 4 ) electrolyte solution. Furthermore, the solution resistance, charge transfer resistance, and internal resistance are obtained to be 5.2, 13.1, and 20.9 Ω for high‐performance PANI/TRGO‐MnO 2 hybrid, respectively.