A Goldilocks Approach to Water Management: Hydrochannel Porous Transport Layers for Unitized Reversible Fuel Cells

This work presents a novel porous transport layer (PTL), the hydrochannel PTL, that enables improved water management and record high round trip efficiency in unitized reversible fuel cells (URFCs). URFCs require rapid transport of O-2 and H2O to provide high performance in both fuel cell and water electrolyzer operation, but cell design is complicated by conflicting water management requirements: electrolyzers perform best with high liquid water saturation, whereas fuel cells perform best when liquid water saturation is as low as possible while still maintaining effective ionomer hydration. The hydrochannel PTL circumvents this obstacle by providing hydrophilic channels for water transport through an otherwise hydrophobic PTL, enabling optimal performance in both fuel cell and water electrolyzer modes. Neutron radiography measurements of water content in both operating modes confirm that the hydrochannel PTL enables high performance due to its improved water management capabilities.

Automated summary

This research introduces a new porous transport layer (PTL), called hydrochannel PTL, that improves water management and achieves record high round trip efficiency in unitized reversible fuel cells (URFCs). URFCs require fast transport of O2 and H2O for high performance in both fuel cell and water electrolyzer modes, but the conflicting water management requirements make cell design complicated. The hydrochannel PTL addresses this issue by providing hydrophilic channels for water transport through a hydrophobic PTL, optimizing performance in both modes. Neutron radiography measurements confirm that the hydrochannel PTL enhances performance due to its improved water management capabilities.