Preparation process for improving cathode electrode structure in direct methanol fuel cell

The cathode electrode structure of the direct methanol fuel cell (DMFC) was improved by a novel catalyst ink preparation method. Regulation of the solvent polarity in the cathode catalyst ink caused increases in the electrochemical active surface (EAS) for the oxygen reduction reaction (ORR) as well as decreases in the methanol crossover effect. In a two-step preparation, agglomerates consisting of catalyst and Nafion ionomers were decreased in size, and polar groups in the ionomers formed organized networks in the cathode catalyst layer. Despite Pt catalysts in the cathode being only 0.5 mg cm^? 2, the maximum power density of the improved membrane electrode assembly (MEA) was 120 mW cm^? 2, at 3 M methanol, which was much larger than that of traditional MEA (67 mW cm^? 2).