Investigation of titanium liquid/gas diffusion layers in proton exchange membrane electrolyzer cells

ABSTRACT

In a proton exchange membrane electrolyzer cell (PEMEC), liquid/gas diffusion layer (LGDL) is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in PEM fuel cells (PEMFCs), are unsuitable in PEMECs due to the high ohmic potential and highly oxidative environment of the oxygen electrode. In this study, a set of titanium gas diffusion layers with different thicknesses and porosities are designed and examined coupled with the development of a robust titanium bipolar plate. It has been found that the performance of electrolyzer improves along with a decrease in thickness or porosity of the anode LGDL of titanium woven meshes. The ohmic resistance of anode LGDL and contact resistance between anode LGDL and the anode catalyst play dominant roles in electrolyzer performance, and better performance can be obtained by reducing ohmic resistance. Thin titanium LGDLs with straight-through pores and optimal pore morphologies are recommended for the future developments of low-cost LGDLs with minimum ohmic/transport losses.

KEYWORDS:

• Electrochemical impedance Spectroscopy
• liquid/gas diffusion layer
• proton exchange membrane electrolyzer cell
• porosity
• thickness

Acknowledgments

The authors wish to express their appreciation to Dr. Bo Han, Doug Warnberg, Aaron Liu, Kate Lansford, Rong Chen, Dr. Lino Costa, Nikko Techno, and Alexander Terekhov for their help.

Funding

The authors greatly appreciate the support from the US Department of Energy’s National Energy Technology Laboratory under Award DE-FE0011585.

Additional information

Funding

The authors greatly appreciate the support from the US Department of Energy’s National Energy Technology Laboratory under Award DE-FE0011585.