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.