Performance Comparison of Proton Exchange Membrane Fuel Cells with Nafion and Aquivion Perfluorosulfonic Acids with Different Equivalent Weights as the Electrode Binders

A perfluorosulfonic acid (PFSA) ionomer, used as the proton conductor in the catalyst layer, influences significantly the performance of proton exchange membrane fuel cell catalyst-coated membrane (CCM). In this paper, SSC-CCM is prepared by the SSC-PFSA (Aquivion, EW 720) ionomer, and the comparative sample (LSC-CCM) is based on the LSC-PFSA ionomer (Nafion, EW 1100). Compared with LSC-CCM, SSC-CCM shows higher porosity, larger electrochemical surface area (ECSA), and smaller high-frequency resistance. Polarization curves of SSC-CCM tested by the short stack show better performance than those of LSC-CCM, especially under the lower relative humidity operations. Moreover, the SSC-CCM outputs higher voltage and is more stable in the dynamic process with temperature continuously increasing under lower relative humidity operation. Such excellent performance of SSC-CCM is confirmed from the higher proton conductivity of SSC-PFSA under low relative humidity. These results indicate that the SSC-PFSA ionomer could be employed for the CCM catalyst layer under the operation conditions of low relative humidity and dynamic running for automotive applications.