Hydrogen is a key player in the future of clean energy, and electrolysis—splitting water into hydrogen and oxygen using electricity—is one of the most promising ways to produce it.
But there’s a hidden cost: the devices used in this process, called solid oxide electrolysis cells, are made with rare and valuable metals that usually end up as waste.
Now, researchers in Germany have come up with a method that could change that.
A team at TU Bergakademie Freiberg has developed a way to recover rare earth metals from used hydrogen electrolysis cells, so they can be reused instead of discarded.
These metals—such as scandium, lanthanum, and cerium—are vital components in producing hydrogen, and each 10-megawatt electrolysis module contains about 150 kilograms of them.
Until now, these materials were lost when the cells were retired and ended up as scrap steel. The new method could dramatically cut down on that waste.
The team’s approach involves a process called hydrometallurgy, which uses liquids—specifically, acid-based solutions—to dissolve and extract the metals.
First, they mechanically separate the electrode materials from the steel parts of the electrolysis cell. Then, they use leaching techniques to pull the rare earth metals into a liquid form, which can then be processed and reused.
So far, the team has tested this process on a small scale in the lab, using just 0.2 grams of cell material at a time.
But the results are promising, and they are already scaling up to test it on samples of up to 50 grams. In future stages, they plan to further refine the process to separate and purify each metal in an environmentally friendly way.
Dr. Pit Völs, one of the researchers involved, says the ultimate goal is to return these rare metals to the production cycle, reducing the need to mine new materials and lowering the environmental footprint of hydrogen technology.
A simulation-based life cycle assessment will also be used to measure the environmental impact of the recycling method itself.
The work is part of the larger GrInHy3.0 research project, which brings together academic and industry partners. The recycling technology will eventually be tested in real-world conditions with companies like Sunfire SE, which manufactures electrolyzers, and Salzgitter Flachstahl GmbH, a major steel producer.
The aim is to develop a commercial plant that can produce 14 kilograms of hydrogen per hour—while also making sure that the rare earth materials used in the process don’t go to waste.
This recycling breakthrough could help make hydrogen an even more sustainable part of our clean energy future.
Source: KSR.
