(422a) Durable, Self-Hydrating, Tungsten Carbide-Based Composite Polymer Electrolyte Membrane Fuel Cells

Proton conductivity of the polymer electrolyte membranes in fuel cell (PEMFC) dictates the performance and requires sufficient water management. Here, we introduce a simple scalable method to produce well-dispersed transition metal carbide (TMC) nanoparticles with narrow size distribution (3-5 nm). This protocol can be extended to the synthesis of other early transition metal carbides. Extensive characterizations including HRTEM, STEM tomography, SEM, XPS, XRD and TG are conducted.

WC nanoparticles incorporated into a recast Nafion membrane demonstrate significant improvement of the PEMFC power density compared to the baseline Nafion membrane. Based on both theoretical and experimental results, the WC composite membrane catalyzes the reaction of crossover H₂/O₂ and provides sufficient water management within the membrane, improving the proton conductivity. Tomographic studies using FIB-SEM indicate large pinholes forming around Pt nanoparticles and provide support that the membrane/Pt catalyst facilitates the production of radicals that leach from Nafion. Superior to Pt, incorporated WC nanoparticles in the membrane result in considerable durability of the membrane. DFT calculations provide insights into the mechanisms by which WC improves performance.