Electrolyte degradation mitigation in PEM fuel cells

Electrochemical and spectroscopic diagnostics are employed to investigate PEM degradation under conventional and accelerated test conditions. Platinum microelectrodes and bifurcated fiber optic probes are used to estimate the amount of hydrogen peroxide and other reactive oxygen species (free radicals) generated in-situ within the PEM during fuel cell operation. These measurements are correlated to fluoride emission rate data obtanined under similar operating conditions to shed further light on the mechanism of PEM degradation. Selected non-stoichiometric metal oxides and metal nanoparticles are employed to mitigate PEM degradation by promoting radical scavenging. The influence of parameters such as oxygen vacancy fraction (metal oxides) and zeta potential on the efficacy of degradation mitigation using these additives is explored. Over one order of magnitude reduction in the macroscopic rate of PEM degradation (with no detrmental impact on performance) is observed when these additives are incorporated within the PEM.