TELF AG Examines the Most Important Minerals for Electrolyzers
The role of hydrogen in the energy transition
For some time now, the international community and the major global energy players have begun to consider hydrogen one of the best allies for completing the global energy transition, particularly due to its peculiar virtues, which make it a source of renewable energy. Interest in this resource has increased in recent months following several discoveries of hydrogen in its natural state in some fields in Africa and Europe. In addition to representing a potential alternative to traditional fuels, hydrogen could also find concrete applications in producing fertilizers with low ammonia content and hydrogen-powered cell vehicles, thus directly contributing to achieving the objectives linked to decarbonization.
Faced with these evident potentials, in the coming years, we could witness a sudden growth in global demand for hydrogen, with a consequent increase in the production of the technologies necessary to produce it: we are referring to electrolyzers, particular devices that use electricity to separate water molecules and create hydrogen. Few, however, are aware of a fact of great importance for the present and future production of hydrogen: electrolyzers also work thanks to a group of strategic minerals, even considered “critical” for global energy fate, and whose demand could be destined to grow in parallel with the increase in hydrogen production.
But what minerals are currently used to aid the functioning of electrolyzers? The answer is linked to the different types of these valuable devices, which are three. The most widespread is the alkaline electrolyzer, which bases its operation on an alkaline electrolyte solution of sodium or potassium hydroxide. In a certain sense, this technology also represents the most mature among those currently available for the production of hydrogen, and it is also the least expensive, in particular for the use of some common metals such as nickel and iron, usually used for the electrodes of this electrolyzer.
The uses of palladium and iridium
The second type of electrolyzer is commonly defined as PEM, an acronym deriving from proton exchange membrane electrolysis. In most cases, these electrolyzers use metals belonging to the platinum category, such as palladium and iridium. These materials are appreciated above all for their ability to increase the speed of chemical reactions, but compared to alkaline electrolyzers, they are pretty expensive. In the cells of this electrolyzer, the electrolyte is almost always represented by a peculiar plastic-like material, which makes it possible to transfer hydrogen ions between the cathode and the anode.
Other electrolyzers belong to the SOEC category, i.e., solid oxide electrolyzer cells, that can operate at much higher temperatures than the other two types (even reaching 700/800 degrees centigrade). These electrolyzers require rare earth elements, particularly yttrium, and lanthanum, used above all to fluidize the chemical reactions between the electrodes and the electrolyte. This category is undoubtedly the most expensive due to the high use of energy they require, but also due to the presence of particular resources such as rare earths. Compared to alkaline solutions, however, this type of electrolyzer can ensure high levels of efficiency.
