(161k) 3D Patterned Electrodes for Ultra-Low Platinum Fuel Cells

Previous work in our laboratory demonstrated the production of nanofiber-nanoparticle electrodes via simultaneous electrospinning/electrospraying that resulted in ultra-low platinum fuel cells, i.e., similar fuel cell performance with an order of magnitude lower platinum content compared to conventional electrodes. However, previously developed nanofiber-nanoparticle electrodes were randomly oriented. Can ordered structured nanofiber/nanoparticle electrodes improve fuel cell platinum utilization? In this study, a new fabrication technique was developed, templated-assisted E/E, which successfully produced organized structured nanofiber-nanoparticle electrodes with 3D hexagonal patterned arrays of various pattern sizes (hexagonal pattern diameters of 40, 80, 160, and 360 µm). At similar platinum loadings, patterned electrodes exhibited higher power densities and electrochemical surface area compared to randomly oriented electrode analogs (i.e., high fuel cell platinum utilization). Among the different pattern sizes, electrodes with 80 µm diameter hexagonal pattern resulted in the highest platinum utilization and lowest electrode resistance. Additionally, patterns did not compromise the mechanical strength of the electrodes. Compared to electrodes produced from conventional techniques and other ink-based patterning techniques, the template-assisted E/E technique provides a versatile platform for investigating the effect of pattern type and size on fuel cell platinum utilization.