Characterization of direct methanol fuel cell components by electron microscopy and X-ray microchemical analysis

Transmission and scanning electron microscopy techniques were used in conjunction with X-ray microchemical analysis to investigate the structure, morphology and composition of direct methanol fuel cells components. Two different preparation methods were adopted for fabrication of membrane-electrode assembly. The first was based on a conventional method involving ionomer spreading on electrodes, the second method concerned the direct mixing of catalyst and ionomer. The latter method allowed improved electrochemical activity and conductivity characteristics to be obtained. According to electron microscopy and X-ray microchemical analyses, the observed results were attributed to an improved bonding between catalyst and ionomer and to a larger extension of the three-phase reaction zone at the electrode-electrolyte interface.