Improved Performance of the Membrane-Electrode Assemblies with Titanium Metallic Foams in Fuel Cells

Fuel cells are attracting significant attention as a promising futuristic technology for energy conversion. Their energy densities are orders of magnitude greater than those of conventional batteries, capacitors, and are even comparable to the power and energy densities of internal combustion engines. Because the key component of the fuel cell performance is the structure of electrode in the membrane electrode assemblies (MEAs), the optimization and modification of the electrode structure has been the main research subject for the performance and the durability improvement of polymer electrolyte membrane fuel cells (PEMFCs). This study uses a new design approach for the MEA: use of titanium foam as gas diffusion layer (GDL). In other words, freeze-cast titanium foams are applied to the MEAs in place of the GDL, resulting in a significant improvement of the MEA in the single cell performance test. This is because of its unique three-dimensional strut structure promoting highly efficient catalytic reactions. We believe that this paper suggests implications in the commercialization of PEMFCs, because the Ti foam fabricated in this study provides an excellent electrochemical performance, and longer-term reliability and chemical stability, which can reduce the loss of Pt catalyst and hence, the cost of PEMFCs.