Investigating different break-in procedures for reformed methanol high temperature proton exchange membrane fuel cells

In this study, two set of tests are carried out with different break-in times, the normal break-in (100 h), intermediate break-in (30 and 50 h) and no break-in (0 h). After break-in, all the cells were subjected to a load cycling profile between 0.2 and 0.6 A cm−2 with 5 min at each current density. The test was then carried out to compare the cell performance over time when the break-in is carried out with simulated reformed gas having a composition of 64.7% H2, 21.3% CO2, 12% H2O and 2% CH3OH. The break-in time for this test was 100 h. The cells are operated at 0.2 A cm−2 during break-in and thereafter at 0.6 A cm−2 under normal operation. The cell performance and impedance change over time is analyzed. The different resistances are deduced using equivalent circuit models and analyzed to understand the changes occurring in the MEA during break-in and how they affect the durability of an HT-PEMFC. The degradation rate for the different operating strategy is calculated from the voltage trajectory over time. The comparison of degradation and break-in time suggests that the normal break-in induces a uniform ohmic resistance changes in the cell over time, while the fast cycling leads to non-uniform changes in resistances. However, the performance and degradation are not significantly affected over ≈750 h test. The test with simulated reformed fuel indicates that the break-in with pure H2 is important for longer durability when operation thereafter is with reformed fuel. The cell with reformed fuel break-in degrades much faster compared to the cell with H2 break-in.