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 struc ture, morphology and composition of direct methanol fuel cells compone nts. Two different preparation methods were adopted for fabrication of membrane-electrode assembly. The first was based on a conventional me thod involving ionomer spreading on electrodes, the second method conc erned the direct mixing of catalyst and ionomer. The latter method all owed improved electrochemical activity and conductivity characteristic s to be obtained. According to electron microscopy and X-ray microchem ical analyses, the observed results were attributed to an improved bon ding between catalyst and ionomer and to a larger extension of the thr ee-phase reaction zone at the electrode-electrolyte interface.