Fuel Cell Meas Made Using Electrode Inks with Pre-Formed Particle/Binder Fibers
Authors: Fan Xiaozong , Pintauro Peter N. , Wycisk Ryszard 
Published: December 2024

When fuel cell electrodes are prepared by a conventional spraying or slot-die coating method, there is little or no control over the multi-scale organization of catalyst particles and polymer binder. Electrode structural features such as particle and binder interconnectivity, macro-porosity, and micro-porosity are difficult to control, but are critically important when high-performance nanocatalysts are used. Nanofiber electrospinning is an electrode fabrication technique that can address fuel cell electrode morphology issues for next-generation MEAs. As a commercial fabrication method, electrospinning has been shown to be scalable, robust, and cost-effective, especially for the creation of non-woven mats of sub-micron-diameter polymer fibers. Electrospinning can also be used to prepare particle/polymer fiber networks with intra- and inter-fiber porosity. Such fiber mats have been used as the electrode material in Li-ion batteries, H2/Br2 redox flow batteries, and H2/air proton-exchange membrane fuel cells [1-4].
Recent work on nanofiber electrodes at Vanderbilt has focused on inks containing pre-formed electrospun catalyst/binder fibers. With such inks, nanofiber electrode MEAs can be made using commercial roll-to-roll fabrication lines. In this talk, experimental results will be presented on nanofiber mat electrode MEAs with Pt/C catalyst and Nafion™ binder. Procedures for preparing inks with nanofibers and then using the inks to create CCMs or GDEs will be presented. Fuel cell performance and durability results with the resulting MEAs will be contrasted with fuel cell data where the electrodes are made directly from electrospun mats, i.e., by the direct transfer of a mat from the electrospinner to a GDL or membrane. The effects of catalyst loading and fuel cell operating conditions (backpressure, feed gas flow rate, and feed gas relative humidity) on fuel cell power output before and after metal dissolution and carbon corrosion accelerated stress tests will also be discussed. As an example of nanofiber electrode performance: an MEA with a Nafion 211 membrane and TKK Pt/C anode and cathode catalyst (0.1 mg/cm2 anode and 0.22 mg/cm2 cathode) operating at 100% RH, 80oC, and 3 atm. total pressure generated 1.0 W/cm2 at 0.7 V.

Acknowledgment

This work was funded by the U.S. Department of Energy’s Hydrogen and Fuel Cell Technologies Office, for the Fuel Cell Performance and Durability Project, contract No. DE-EE0007653.

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