Neutron radiographic in operando investigation of water transport in polymer electrolyte membrane fuel cells with channel barriers

Highlights: • New type of flow field channel design with barriers. • 10% performance increase compared to reference PEM fuel cell. • Neutron imaging used to quantify water distribution in operando. • Water around barriers helps to increase catalyst gas supply. • Homogenous water distribution over the whole active area. - Abstract: We present a study on a new type of flow field channel design for polymer electrolyte membrane fuel cells (PEMFCs). Small barriers have been implemented into the flow field channels that force the gas flow to move through the gas diffusion layers in order to improve the supply of the catalyst with reactant gases. We investigated the water distribution in the PEMFC with neutron imaging during operation and compared the results with a comparable reference cell without barriers. We found strong hints for an increased mechanical gas flow resistance by the barriers caused by additional liquid water agglomerations. Furthermore water distribution in the barrier flow field is much more homogenous compared to the reference cell. We assume that both effects, namely the gas flow through the GDL and the homogenous water distribution are responsible for the found performance increase of up to 10%.