Fossil fuels are nearing extinction
Electrolyzer, a plausible solution?
Logistical challenge
A solution might be simple: skip the transportation phase and create hydrogen gas with an electrolyzer at the location where it will be used. For instance it can be used to store excess production of green energy. However even the latest designs are still too small to provide a whole house with the needed supply of hydrogen to generate electricity. The main culprit is the membrane, which proves a real challenge to be upscaled to fit an economically feasible electrolyzer to be used on consumer, let alone industrial, scale.
This challenge is especially prominent for electrolyzers since the conditions of fuel cells are less aggressive for the metal. In the following paragraphs we will elaborate on the specific approach for materials selection for fuel cells and electrolyzers
Corrosion in fuel cells: steel vs. titanium
Even though fuel cells offer a less extreme environment for the metal plates than electrolyzers, corrosion is still a delicate yet important matter in fuel cells. The allowed corrosion rate should be in the range of µm/year, this is the result of the low tolerance towards corrosion since it has a direct negative effect on the performance.
When we take a closer look at the materials that are used in fuel cells, generally high-alloy stainless steels (such as superduplex, superaustenitic ) or titanium are used. Although titanium has beneficial properties for use as base material in fuel cells, hydrogen does react with titanium. This reaction results in the formation of titanium hydride (TiH2) which causes the base material to be more brittle. When titanium is chosen in fuel cells, extra measures are taken against hydrogen embrittlement by applying surface coatings like titanium nitride.
Corrosion in electrolyzers: material selection is key
Materials selection in electrolyzers proves to be more tricky. On one hand, an electrolyzer requires a chemically resistant material that can withstand the corrosive environment. But on the other hand, the material needs to be stackable, and thus malleable. This creates a new challenge: in order to be deformable, the material should be thin which in turn reduces its service life in case corrosion occurs. A possible solution lies again in applying a thin, conductive protective layer (such as titanium nitride or platinum).
Tests to ensure you chose the right material
Research with regard to materials selection is ongoing. You may wonder where to start when choosing the right material and the extra measures that might come along in protection against corrosion.
To conduct this comparative analysis between different options, it is commendable to conduct electrochemical research, such as cyclic polarization tests with Tafel analysis. This kind of measurement is performed by means of a potentiostat. The measured corrosion current density in µA/cm² is converted into a corrosion rate in µm/year. A benefit of this test is the flexibility: the test generally takes less than a day which makes it possible to perform the test with different solutions or materials, even ones that you have not had any experience with.
Are you interested in getting to the bottom of what material works best for you by having an electrochemical test performed? Or are you looking to equip your lab with a potentiostat? Don’t hesitate and contact us right away for more information!