Synthesis and characterisation of polyaniline/polyvinyl alcohol composites as supercapacitor electrode materials

Abstract

Composites of polyaniline and polyvinyl alcohol were prepared through an in-situ polymerisation of aniline using ethanol as a coagulating agent and characterised for their applicability as supercapacitor electrode material. The thermally stable composites afford moderately high electrical conductivity. Composite with 0.03 mol aniline exhibited a high electrical conductivity of 0.371 × 10⁻² S/cm. The variation in electrical conductivity with an increase in aniline content is consistent with the band gap energies estimated from electronic spectra and IR drop. SEM analysis confirms coral-like nanowires of polyaniline (PANI) grown within the polyvinyl alcohol matrix. Cyclic voltametric studies revealed that the composites are highly electroactive as they allow easy diffusion of ions through the nanowires of PANI for efficient electrochemical reaction. The composite with 0.03 mol aniline has a superior specific capacitance of 302 Fg⁻¹ at a scan rate of 5 mV/s. The composite exhibited a maximum energy density of 41.94 Whkg⁻¹ and excellent stability even after storage of 18 months in ambient condition with 83.3% capacitance retention.