| Summary: | 碩士 === 大同大學 === 機械工程學系(所) === 100 === This study focused on the microporous layer in a high temperature proton exchange membrane fuel cell. The effects of the type of carbon black and the amount of carbon loading are analyzed experimentally. The operating conditions for the fuel cell are fixed at temperature 180℃ with PTFE content 40% in the microporous layer and Pt loading 1.0 mg/cm2 in the catalyst layer. The hydrogen and air flow rates are 150 and 350 sccm, respectively. Both reactant flow streams are fully humidified before entering the fuel cell. The variations of polarization curve are measured and the method of electrochemical impedance spectroscopy (EIS) is used to evaluate the fuel cell performance. The results show that the fuel cell has the optimal performance when the carbon loading is 1.0 mg/cm2 in the microporous layer. Three different kinds of carbon black are considered: acetylene black (AB), Black Pearls 2000 (BP), and composite carbon black. For both acetylene black and Black Pearls 2000, the test results show that Acetylene Black gives better cell performance than that of Black Pearls 2000 when the carbon loading is the same in the microporous layer. With the same amount of carbon loading, the composite carbon black is used which is composed of acetylene black and Black Pearls 2000. Different ratios of both carbon blacks are considered in the measurements and the results show that when the AB/BP ratio is 9:1 in the composite black, the fuel cell has the best cell performance.
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