EQCM Studies of Polyaniline Film in a H2SO4 Solution in Ethylene Glycol

Electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements was applied to investigate the redox process and the electrochemical performance of polyaniline (PANT) in 0.5 M H2SO4 solution in ethylene glycol (EG). Especially, ionic fluxes and solvent molecules involved in redox processes of PANI were analyzed by EQCM technique. Unlike the aqueous solution, in the EG solution, anions and solvent molecules always migrate in opposite directions simultaneously during the redox switching of PANI. Anion incorporation or expulsion is always accompanied by desolvation or solvation processes. The suitable potential window in the EG solution is from -0.2 to 0.6 V to prevent the degradation of PANI at high potential. In addition, PANI exhibited excellent cycling stability with a capacitance retention of similar to 89.1% after 2000 cycles. The nonaqueous EG electrolyte is believed to be associated with good cycling stability. (C) 2018 The Electrochemical Society.