Studying the supercapacitive behavior of a polyaniline/nano-structural manganese dioxide composite using fast Fourier transform continuous cyclic voltammetry

Abstract

In this work the supercapacitive behavior of electrochemically synthesized polyaniline/nano-structural manganese dioxide composite (PANI/NsMnO₂) on a glassy carbon electrode (GCE) was studied. NsMnO₂ was synthesized by an ultrasound method. PANI/NsMnO₂ was synthesized by cyclic voltammetry in a 1 M H₂SO₄ solution containing the aniline monomer (0.03 M), NsMnO₂ (0.2% wt) and 5 mM sodium dodecyl sulfate (SDS). The average size of the NsMnO₂ which was distributed uniformly throughout the composite was 60 nm. Cyclic voltammetry (CV), galvanostatic charge–discharge (CD), electrochemical impedance spectroscopy (EIS) and fast Fourier transform continuous cyclic voltammetry (FFTCCV) methods were used for the study of the supercapacitive properties of the composite electrode. For morphology and structural characterizations of the composite electrode scanning electron microscopy (SEM) and fast Fourier transform infrared spectroscopy (FTIR) were used. Using cyclic voltammetry the specific capacitance values of PANI and PANI/NsMnO₂ were calculated to be 190 and 507 F g⁻¹ respectively. The stability of the two electrodes were measured and compared together with the FFTCCV technique. The presence of NsMnO₂ caused an increase in the stability of electrodes from 30% for PANI to 90% for the PANI/NsMnO₂ electrode. Furthermore by using the FFTCCV technique changes in the electrochemical behavior of the PANI/NsMnO₂ composite electrode over time were scrutinized.