Electrochemical behaviour of stand-alone polyaniline–poly(vinyl alcohol) composite films

In this report, we investigate the electrochemical capacitance and redox behaviour of a stand-alone polyaniline–poly(vinyl alcohol) composite film cast on an insulating substrate (normal printer paper) and compared it with an electrochemically synthesized composite film deposited on a gold electrode. The stand-alone composite film showed timescale-dependent, wide range charging–discharging redox cycling and high electrochemical capacitance in potentiodynamic electrochemical experiments carried out in 1 M HCl solution.The stand-alone composite film exhibited two distinct current density responses during redox switching. This might be attributed to the different doping and de-doping modes, represented by ions trapped at deep and shallow levels in the bulk of the composite polymer film and the double layer of the modified electrode–electrolyte interface.The wider electrochemical window and higher capacitance response of the stand-alone film are important for battery technology and in energy storage and conversion devices.