Chemistry and Degradation Mitigation Effect of Cerium Oxide in Polymer Electrolyte Membranes

摘要: One of the main obstacles to wide-spread commercialization of polymer electrolyte membrane fuel cells (PEMFC) is the short operational lifetime of perfluorosulfonic acid (PFSA) membranes used in these devices. Various radical oxygen species are considered to be the main degrading species for PFSA membranes.[1]Radical scavenging properties of cerium oxide Ce(III)/Ce(IV) redox couple in the biological environment are well-known and hence its application in PEMFC, as a degradation mitigator, has received considerable attention.[2, 3] In this work, two cerium oxide nanoparticle formulations with an order of magnitude difference in average size (2-5nm and 20-150nm) were added to 1100 EW PFSA membranes in 0.5, 1.0 and 2.0 wt% loading. We will discuss that ceria, in the acidic environment of heated/humidified membranes, is reduced to Ce(III) ions which negatively impacts proton conductivity. Both …