Abstract
Electrospun nanofiber electrodes for hydrogen/air fuel cells were prepared using poly(ethylene oxide) (PEO) carrier polymer, where previous publications used poly(acrylic acid) (PAA). Electrospinning with PEO carrier is only possible when the ink contains Nafion® in its salt form. Fiber electrodes were evaluated in 5 cm2 membrane-electrode-assemblies (MEAs) and exhibited excellent power at high and low feed gas relative humidities. For example, a nanofiber cathode MEA made from an ink containing Na+-form Nafion, PEO, and Pt/C generated 822 mW/cm2 at maximum power, 40% RH, 80 °C, and 200 kPaabs, whereas PAA-based ink electrode MEAs produced 527 mW/cm2. Changes in PEO molecular weight had no notable impact on fuel cell performance. Different Nafion counter-ions were studied. The use of Cs+-form Nafion resulted in the best MEA performance, producing 919 mW/cm2 at maximum power under full humidification and 800 mW/cm2 at 40% RH.
