Analyses of scanning electrochemical microscopy and electrochemical impedance spectroscopy in direct methanol fuel cells: permeability resistance and proton conductivity of polyaniline modified membrane

Nafion 112/polyaniline (Na/PANi) composite membranes were synthesized by chemical polymerization of aniline on the perfluorinated structure for use in direct methanol fuel cells as a solid electrolyte. The morphology and physicochemical properties of the composite membranes were analyzed by scanning electron microscopy (SEM), attenuation Fourier reflection infrared spectroscopy (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the membranes were investigated by scanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The results show that PANi-modified Nafion during 1 and 24 h decrease the methanol crossover by 78% and 89% and increase the proton conductivity by 17% and 2.6% respectively.