Preparation Method Of Ultra Low Platinum Loading Electrodes For Polymer Electrolyte Fuel Cells

Yuko Fukuoka, Makoto Uchida, Yasushi Sugawara, Nobuo Eda, and Akira Ohta Technology Laboratory, Matsushita Battery Ind. Co., Ltd. X, Matsushita-cho, Moriguchi, Osaka, 570, Japan

Polymer electrolyte fuel cells (PEFCs) necessitates platinum (Pt) catalyst for its operating temperature. It is important to enhance the utilization of Pt for the cost. The reaction sites exist on the Pt surface covered with perfluorosulfonate ionomer (PFSI) in PEFC. PFSI solution was usually impregnated into the catalyst layers to increase the contact areas. We proposed a preparation method of the M&E assembly which emphasized the colloid formation of the PFSI to optimize the network of PFSIs in the catalyst layer.1 After this work, we focused on the microstructure of the catalyst layer. We recently reported that the PFSI was distributed only in the pores formed between the agglomerates, and the reaction sites were therefore limited to that area.2 The results indicated that the PEFC system required a particular design compared with a conventional one3 with liquid electrolytes. We proposed novel structure and/or preparation methods of the catalyst layer to be key issues to get higher Pt utilization. We studied the effect of the carbon support on the cell performance.4 The performance was improved by an optimal carbon support: that has (i) a larger pore volume (0.04 to 1.0 pm in diameter) able to be distributed the PFSI and (;'i) smaller pore volume (< 8 nm in diameter) on the surface of the carbon primary particles. We report here the high dispersion method of the PFSI colloid to lower Pt loading with optimal carbon support.

0 0

Post a comment