Performance of high temperature fuel cells with different types of PBI membranes as analysed by impedance spectroscopy

In order to study how PBI membranes influence the operation of HT-PEFC cathode we analyse the performance of HT-PEFC based on three different PBI membrane types (meta-PBI, ABPBI and PBI-O-PhT) by means of stationary voltamperometry and impedance spectroscopy. For impedance spectra interpretation we use an equivalent circuit containing transmission line distributed element. This approach allows us to measure the distributed ohmic resistance of proton transport inside cathode catalyst layer. It is shown that this resistance depends on the membrane type used and has even more pronounced influence on the FC performance than ohmic resistance of the membrane itself.

▶ We compare the performance of HT-PEFC based on PBI, ABPBI and PBI-O-PhT membranes by means of impedance spectroscopy. ▶ Transmission line equivalent circuit for impedance spectra interpretation and measuring cathode active layer resistances. ▶ Ohmic losses in cathode catalyst layer are greater than ohmic losses in membranes. ▶ Catalyst layer resistances depend on membrane type.