Long Term Testing in Continuous Mode of HT-PEMFC Based H3PO4/PBI Celtec-P MEAs for μ-CHP Applications

Fuel cells have a promising market in micro-combined heat and power (mu-CHP) applications by reducing primary energy demand and CO2 emissions. But current proton exchange membrane fuel cells (PEMFC) operate at too low temperatures to cope with return temperatures of typical heating systems and needs complex regulations at system level to prevent degradations. Operating beyond 150 degrees C, high temperature PEMFC (HT-PEMFC), based on H3PO4/PBI technology, would avoid these issues and allow system simplification. Single cell and 500 We stack integrating Celtec P1000 MEAs were operated in continuous made at 0.4 A cm(-2) and 160 degrees C, under simulated reformate and air. Single cell's ohmic resistivity was almost unaffected by 1,100 h of ageing but the cell progressively switched from a cathodic to an anodic mass transfer limited operation. The stack was operated for 658 h, exhibiting the same behaviour and an additional increase in cell voltage distribution heterogeneity. CO2 proved to have negligible effect on performances but performance losses induced by ageing are doubled in the presence of CO. Post-testing experiments revealed that anode electrochemical active area was dramatically decreased and that platinum content was also decreased. Finally, results showed that a convenient shut-down procedure could prevent or limit degradations associated with storage.