30 μm Thin Anode Gas Diffusion Layers for Optimized PEM Fuel Cell Operation at 120 °C and Low Relative Humidity

Abstract

Achieving higher temperature operation above 100 °C, while increasing the volumetric power density are key targets in current fuel cell development. In this work, a novel type of polyvinylidene fluoride and graphite based microporous film of only 30 μm thickness, acting as thin alternative to typical gas diffusion layers (GDLs) on the anode side of a hydrogen fuel cell is reported. Ex situ measurements (contact angle, electric conductivity, gas permeability measurements, and scanning electron microscopy (SEM)) reveal that the thin, porous layers achieve comparable chemical, electrical, and transport properties to commonly employed and significantly thicker gas diffusion layers. In‐situ fuel cell tests reveal considerable improvements, particularly in the target operation range beyond 100 °C: At 120 °C and 30% RH and 0.65 V cell voltage, the best thin anode layer enables a 51% higher current density (1342 vs 885 mA cm−2) and a 9% lower high frequency resistance (76 vs 84 mΩ cm−2) compared to a commercial state‐of‐the‐art GDL.

Effects of Humidity and Produced Water on Specific Adsorption of High Oxygen Permeability Ionomers Composed Entirely of Cyclic Monomers on Cathode Performance for Polymer Electrolyte Fuel Cells

“…Furthermore, under the premise that this hypothesis is correct, it suggests that the impact of the ionomer’s specific adsorption, traditionally considered to have a negative impact under all operating conditions, may be small in the actual operating current density region of MEAs where sufficient water is present. For future applications of HDVs requiring high-temperature operation and performance realization at 20–30% RH, aiming at greater efficiency and cost reduction, this hypothesis could provide important insights when discussing the influence of ionomer-specific adsorption under such operating conditions. , Further discussion will be needed on the validity of the above hypothesis; however, from the fact that the impact of the ionomer structure is significant, we believe that carefully examining the correlation with ionomers with various molecular structures will aid in the verification of the hypothesis. In addition, the occurrence of the step is not necessarily universal.…”