UNDERSTANDING THE DEGRADATION MECHANISMS OF MEMBRANE-ELECTRODE-ASSEMBLY FOR HIGH TEMPERATURE PEMFCS AND OPTIMIZATION OF THE INDIVIDUAL COMPONENTS
The objective of the present proposal is to understand the functional operation and degradation mechanisms of high temperature H3PO4imbibed PEM and its electrochemical interface.
The state of the art high temperature PEMFC technology is based on H3PO4 imbibed polymer electrolytes. The most challenging areas towards the optimization of this technology are:
- The development of stable, long lasting polymer structures with high ionic conductivity.
- The design and development of catalytic layers with novel structures and architectures aiming to more active and stable electrochemical interfaces with minimal Pt loads or nanostructured alloyed Pt electrocatalysts and catalytic layers, which will be supported on finely dispersed or structurally organized modified carbon supports (nanotubes, pyrolytic carbon) so that a stable electrocatalytic layer with full metal electrocatalyst utilization at the electrode/electrolyte interface can be achieved.
- The understanding of fundamentals of the failure mechanisms. In this way, we can use that information to guide the development of new materials or we can develop system approaches to mitigate these failures. The successful implementation of the project will result in commercially available reliable MEAs. The high temperature MEA will be based on a) ABPBI and variants as control group and b) the advanced state of the art TPS electrolytes based on aromatic polyethers bearing basic pyridine units able to interact through an acid base reaction with H3PO4. These MEAs have been tested at temperatures up to 200oC, where they exhibit stable and efficient operation. In the present proposal these advanced materials in the form of MEAs will be studied and tested in single fuel cells with regards to their operating conditions and long term stability aiming to the development of a series of diagnostic tests that will lead in the design and development of an accelerated test and prediction tool for the MEA’s performance.