High Temperature Polymer Electrolyte Membrane Fuel Cells having certain advantages over the state-of-the-art low temperature fuel cells constitute a key research issue aiming at higher efficiencies, cost reduction and compactness. One of the most important issues for the market penetration of fuel cells is their reliability and long term stable operation. More specifically, the activities of the DeMStack project are on the stack optimization and construction based on the high temperature MEA technology of ADVENT S.A. and its long term stability testing in combination with a fuel processor.

DeMStack aims to enhance the lifetime and reduce the cost of the overall HT PEMFC technology. The strategy aims at improvements based on degradation studies and materials development carried out in previous (FCH JU DEMMEA 245156) and ongoing projects so that they will lead to a reliable cost-effective product that fulfils all prerequisites for relevant field uses. These improvements cope with degradation issues related to catalyst utilization, reformate feed contaminants, uniform diffusivity and distribution of reacting gases in the catalytic layer, H₃PO₄ acid depletion and distribution within the MEA, startup-stop and thermal cycles. The present proposal aims towards high electrical efficiencies of 45%+ for power units and of 80%+ for CHP units, combined with lower emissions in order to compete with existing energy conversion technologies.

The project addresses the following scientific and technological issues regarding the successful implementation of a HT PEMFC Stack into a sustainable hydrogen society:

• H₃PO₃ doped High Temperature Membrane Electrode Assemblies (HT-MEA), being able to operate on a long term basis at temperatures at or above 180^oC.
• Catalytic layers for the HOR and ORR of alternative architectures, chemical structures and low Pt loadings (threefold decrease).
• Bipolar plates of novel design which can promote the operating performance of the MEA, thus minimizing corrosion and prolonging endurance at the high operation temperatures. This task is assisted both through targeted modelling and innovative experimental methodologies.
• Simplified design and manufacturing of the cell and stack configurations.
• Increased efficiency, robustness, durability and drastic cost decrease in HT PEMFCs
• A “ready to use” integrated “fuel processor/fuel cell stack” system with high electrical and overall CHP efficiencies.