Superhydrophilic porous transport layer enhances effciency of polymer electrolyte membrane electrolyzers

Published

October 20, 2021

Author(s)

Benzhong Zhao, ChungHyuk Lee, Jason K. Lee, Kieran F. Fahy, Jacob LaManna, Elias Baltic, David Jacobson, Daniel Hussey, Aimy Bazylak

Abstract

Hydrogen is widely regarded as a promising vehicle for renewable energy storage due to its versatility and high energy density. A prominent technology for hydrogen generation is the polymer electrolyte membrane (PEM) electrolyzer, which decomposes liquid water into hydrogen and oxygen gas. However, the energy efficiency of PEM electrolyzers must improve dramatically in the coming years to become economically competitive at large scales. Here, we engineer the wettability of commercial titanium porous transport layers (PTLs) to make them superhydrophilic. We nd the superhydrophilic PTLs increase the efficiency of PEM electrolyzers by up to 20% at high current operations. We show via electrochemical analyses and in operando neutron imaging that the improved efficiency stems from reduced oxygen gas saturation in the anode PTL, which significantly decreases the mass transport overpotential. We conduct ex-situ microfluidic experiments and demonstrate that capillary-driven corner flow is the key physical mechanism responsible for the reduced oxygen gas saturation and enhanced liquid water transport in superhydrophilic PTLs. Our findings illustrate the importance of PTL wettability on mass transport in PEM electrolyzers and enable design of next generation electrolyzers with much greater efficiency.

Citation

Cell Reports Physical Science

Pub Type

Journals

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Keywords

neutron imaging, electrolyzer, flow visualization

Citation

Zhao, B. , Lee, C. , Lee, J. , Fahy, K. , LaManna, J. , Baltic, E. , Jacobson, D. , Hussey, D. and Bazylak, A. (2021), Superhydrophilic porous transport layer enhances effciency of polymer electrolyte membrane electrolyzers, Cell Reports Physical Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932665 (Accessed March 17, 2025)