PSEUDOCAPACITANCE PROPERTIES OF ELECTRODEPOSITED HYBRID FILMS OF POLYANILINE AND MANGANESE DIOXIDE ON STAINLESS STEELS

Abstract

Hybrid films of polyaniline and manganese dioxide (PANi/MnO₂) were synthesized on stainless steels in different solutions containing aniline and MnSO₄ through potential cycling technique. The obtained films showed pseudocapacitive properties from 0 to 0.65 vs Ag/AgCl in aqueous solution of 0.5 M Na₂SO₄. While in 0.5 M H₂SO₄, the films displayed characteristic redox peaks of polyaniline (PANi) on cyclic voltammograms. The codeposition of MnO₂ with PANi had dramatic effect on capacitive behavior of the obtained hybrid films. In comparison with the sample pure PANi only achieving the specific capacitance of 420 F/g, after co-deposition with MnO₂, capacitive behavior was improved significantly. A specific capacitance maximum of 508F/g was obtained responding to sample M50 prepared in the solution containing 50 mM Mn²⁺ at a scan rate of 5mV/s. The sample also displayed a coulombic efficiency 98% over 800 cycles with 67% specific capacitance maintained.