Performance of Membrane Electrode Assemblies: The Importance of Electrode Structure Ageing

Kurzfassung

To meet the requirements of membrane electrode assemblies (MEAs) for polymer electrolyte fuel cells (PEMFCs) for automotive applications it had been agreed by the European Commission that a durability of at least 5,000 h, corresponding to a degradation rate of 10 μV/h, and a high power density of 1 W/cm2 at 670 mV cell voltage need to be achieved. In order to achieve cost competitiveness of PEMFCTo make the PEMFC competitive, in parallel, the Pt amount needs to be reduced to values around or below of 0.2 mgPt/cm2. Clearly, the reduction of Pt loading leads to substantial reduction of power density and also to a reduced lifetime. IMPACT’s study on the relationship of catalyst loading with performance and degradation clearly shows that a reduction of electrochemical active surface area (ECSA) by a factor 2 leads to a performance reduction by around 10% and an increase of reversible degradation rate by a factor 4.