Fabrication of a Ti-based 3D porous transport layer for PEMWEs using ShockWave-induced spraying and cold spray

Cost-effective production of green hydrogen is contingent upon reducing the capital cost of Polymer Electrolyte Membrane Water Electrolysers (PEMWE). Currently, 17 to 25 % of the production cost of a PEMWE stack depends on components related to the Porous Transport Layer (PTL). PTLs are usually made of compressed and sintered titanium powders/fibers to provide them with structural and chemical integrity with carefully controlled interconnected porosity. Herein, we report on the preparation of Ti-based PTLs produced by Shock-Wave Induced Spray (SWIS) and Cold Gas Dynamic Spray (CGDS), two deposition processes that does not require any subsequent heat treatment. This report investigates the effect of using porogens to control the porosity of the Ti-based PTLs. Two porogens, Cu and Al, were used to investigate the effect of porogen density on the deposition efficiency and porosity of the resulting coatings. The Al porogen allowed for the production of Ti-based PTLs coatings with ca. 60 % porosity, which is a very desirable feature for producing PTLs with high gas permeability.