Durable Fuel\nCell Electrode Design via Efficient Distribution\nof the Acidic Ionomer

Proton Exchange Membrane (PEM) fuel cell based electrochemical\nenergy conversion systems represent a cleaner alternative to replace\n diesel-based internal combustion engines for heavy-duty vehicle (HDV)\napplications. Enhanced durability of the fuel cell cathode is critical\nto decrease the total cost of ownership (TCO) of the vehicles. The\nfuel cell cathode comprises a platinum-based catalyst and perfluorosulfonic\n(PFSA) ionomer, which is needed to aid in proton conductivity, but\nit also creates an acidic environment for platinum dissolution. Here\nwe report a new surface treatment process of the catalyst using an\norganic fluorocarbon molecule to efficiently distribute the ionomer\nand decrease the level of Pt dissolution. This allows for a ∼2-fold\ndecrease in ionomer usage without compromising proton conductivity\n(∼25 mS cm<sup>–1</sup>) due to the condensed, superprotonic\nionomer pathways, thereby significantly improving platinum surface\narea retention. The structure of the electrode design and plausible\nreasons for the improved durability are discussed in detail here.