Revealing the Path-Dependence of Catalyst Degradation in Polymer Electrolyte Fuel Cells

Electro-catalyst plays a central role in many clean energy technology applications including water electrolysis for green hydrogen generation, emission free fuel cells for transportation, electrochemical CO 2 reduction and combine heat and power generation. Electro-catalysts degrade via multiple mechanisms, depending on the exact operating conditions in its life cycles. In this presentation, we demonstrate the dependance of the electro-catalyst degradation in polymer electrolyte fuel cell (PEFC) on the specific “paths” that the fuel cell takes to age. Specifically, differently ordered aging protocols with the same total number of accelerated stress tests (ASTs) cycles ( i.e., 31,000 total cycles including 30,000 cycles of square-wave load/unload ASTs and 1000 cycles of triangular-wave carbon corrosion ASTs) were used to degrade membrane electrode assemblies (MEAs). At the end-of-life, performances were distinct, indicating that depending on the specific aging route taken, the fuel cell catalyst layer degrades differently after same number of total AST cycles. The load/unload aging protocol led to more severe losses of performance when preceding after the carbon corrosion aging ASTs