DOI: https://doi.org/10.29363/nanoge.hfuture.2024.014
Publication date: 27th February 2024
One of the main problems that slows down the implementation of the green hydrogen (H2) economy is the cost of water electrolysis. While part of this cost is associated to the price of electricity, a significant part relies on the parts of the electrolyzers. Despite their advantages, Proton Exchange Membrane Water Electrolyzers (PEMWE) still have to overcome some drawbacks to reduce its hydrogen production cost, while maintaining high efficiencies.
According to IRENA report 53% of the cost of the electrolyzer stack lies on the bipolar plates (BPPs) and 24% on the catalyst-coated membrane (CCM). INTELEC project aims at developing new highly conductive components to reduce the cost of the green-hydrogen generation sensibly.
For decades, thermal spraying has been used for the production of coatings all over the world because of its versatility in industry for machinery and tools preservation, surface protection and corrosion prevention. This study demonstrates the possibilities of Cold Gas Spray (CGS) for the cost-reduction production of a component of PEMWEs, the Bipolar Plates (BPPs), by metal 3D printing. In this process, the incorporation of a mask between the nozzle exit and the substrate will drastically transform the BPP production to a very fast and automatic bottom-up process where material is deposited layer-by-layer for building up the three-dimensional flow field patterns from a flat surface. Microstructure and topography of 3D printed BPPs were inspected by microscopic techniques. For evaluating the fulfilment of BPPs requirements, interfacial contact resistance and corrosion resistance of the new BPPs were characterized following David’s methods and with potentiodynamic tests in O2-saturated H2SO4 solutions, respectively.
Concerning catalyst coated membranes, significant improvements in the research of highly active electrocatalysts by alloying iridium with ruthenium and supporting it on highly porous substrates such as TiO2 nanoparticles, allowing the demonstration of functional devices below 0.2 mg cm-2. TiO2, as n-type semiconductor is commonly used as electron transport layer (ETL) in devices to extract negative charges, and may compromise the long term stability of CCMs by increasing its resistivity due to the filling of oxygen vacancies during operation. INTELEC project demonstrates the feasibility to modify TiO2 with p-type dopants as a highly stable support for iridium oxide electrocatalysts. The electrochemical characterization in a rotating disc elèctrode demonstrates a mass activity over 700 A gIr-1 at 1.6 VRHE and no degradation after 1000 cycles of accelerated electrochemical test.
This work is funded by MCIN/AEI/10.13039/501100011033 and European Union “NextGenerationEU”/PRTR, project TED2021-130461B-I00.