Performance of CCM‐type MEAs based on a CsH5(PO4)2‐doped Polybenzimidazole membrane for HT‐PEMFC

In this study, two kinds of membrane electrode assembly (MEAs) based on the CsH5(PO4)2‐doped polybenzimidazole (PBI) membrane and fabricated by the catalyst‐coated membrane (CCM) method are reported. In the first one, named Type‐GDL/PA MEA, phosphoric acid (PA) is sprayed onto the surface of the gas diffusion layer (GDL), and in the second one, named Type‐CL/PA MEA, PA is sprayed onto the surface of the catalyst layer (CL). The results show that the Type‐CL/PA MEA exhibits significantly higher performance than the Type‐GDL/PA MEA, providing the highest peak power densities of 620 and 413 mW cm−2 at 180°C under humidified H2/O2 and H2/air fuel cell conditions, respectively. Moreover, their performance is promoted in the presence of humidified gas feed streams as compared to dry gas conditions at the same temperature. The electrochemical impedance spectroscopy (EIS) analysis indicates a lower charge transfer resistance for the Type‐CL/PA MEA as compared to the Type‐GDL/PA MEA. The former MEA also presents higher stability, as confirmed by a 100 h durability test, resulting in a voltage degradation rate of 0.17 mV h−1, which is much lower than the corresponding voltage drop of 0.71 mV h−1 for the Type‐GDL/PA MEA.