Identification of the best chemical equivalent ratio to produce emeraldine salt exhibiting better pseudo capacitance

Abstract

This work details the effect of varying the ratio of concentrations of oxidant-to-monomer, in the process of synthesizing Polyaniline (PANI) in emeraldine salt (oxidation state) form for pseudo capacitor application. The formation of emeraldine salt is confirmed by analytical characterizations such as Fourier Transform Infrared spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS) and Raman analysis techniques. The UV/Vis spectroscopic (UV) technique was employed to elucidate the optical band gap of variants. Both DC and AC measurements have shown a maximum total conductivity of 1.296 × 103 S cm−1. The cyclic voltammetry (CV) of variants exhibit reversible redox reactions due to back and forth transitions between emeraldine and pernigraniline oxidation states and high diffusion of ions in the fabricated polyaniline thin films. The electrochemical impedance spectroscopy has shown their low solution resistances and charge transfer resistances behaving like a near ideal capacitor and the specific capacitances of CER variants have been calculated by performing constant current discharge cell test showing a maximum specific capacitance of 30.2 Fg−1. The variants also exhibit better coulombic efficiencies.