Gizmodo Science Fair: A Greener Way to Fuel Nuclear Fusion

Researchers at ETH Zurich, Texas A&M University, Hamad Bin Khalifa University, Canadian Light Source Inc., and the Paul Scherrer Institute are winners of the 2025 Gizmodo Science Fair for safely and sustainably extracting lithium-6—a key fuel for nuclear fusion.

The question

Can electrochemical processes help clean water polluted from fracking? And could the same setup be used to extract lithium-6 from oil field wastewater?

The result

A project led by ETH Zurich suggests we can. The system, which the researchers say is “like a battery in reverse,” works by powering a cell loaded with water, where a negatively charged zeta vanadium oxide electrode bonds with and traps lithium-6 ions. Heavier lithium-7 ions, on the other hand, slip right through the tunnel. This process could compile enough lithium-6 for fueling nuclear fusion within 25 four-hour cycles, according to the paper on this technology, published March 20 in Chem.

Why they did it

Lithium-6 is a rare yet key ingredient in producing tritium, an even rarer isotope of hydrogen used for fusion reactions. Currently, the United States sources its lithium-6 from an old stockpile produced during the Cold War, using a now-banned method to extract it from toxic mercury. Needless to say, we’re just counting the days before we run out.

Sarbajit Banerjee, a chemical engineer at ETH Zurich in Switzerland, has a knack for coming up with creative electrochemical solutions to tricky separation problems. For this particular project, he and his team discovered that an electrochemical cell they set up to separate lithium from contaminated water was so efficient that they began to wonder if this mechanism could be applied elsewhere—like plucking some precious lithium isotopes from dirty water.

“Our initial focus was just removing lithium from [contaminated] water, because of the immense challenges in the lithium supply chain for batteries,” saidAndy Ezazi, study co-author and now CEO of Quiddity Products, a startup hoping to scale this technology for commercial use. The idea to extend the cell’s use for extracting lithium-6 arose rather organically, as the team was pondering the various uses of lithium across industries.

The team eventually figured it out—but it took a lot of trial and error to get there. So what started as a project seeking to clean up polluted water evolved into a technique for sourcing precious lithium-6. “We got through so many leaky pipes and pumps that prop up every few days… Sometimes you’re a nuclear scientist. Sometimes you’re a plumber,” Banerjee joked.

Why they’re a winner

What’s most surprising is that the separation efficiency of the cell is “already competitive with the legacy process that’s been outlawed in the United States,” Ezazi said. “It’s very, very infrequent that a laboratory proof-of-concept is already competitive with the industrial-scale process that has existed.”

“What we have is a complete departure from what has been done before,” Banerjee said. “We basically came up with a technology that is based on slight differences in the rates lithium moves through a solid-state lattice, as [it would] in a battery.”

On the research side, the project is a fantastic demonstration of an interdisciplinary, cross-generational endeavor with real, practical results. Banerjee’s long experience in the field was key to developing the technology. But it was younger members who really brought this to fruition, in addition to partners from NIST and the Canadian Light Source, who helped maximize the material efficiency of the cell, he said.

“We try to be sort of a little bit of an ideas lab, not really trying to do one thing, but just trying to do many, many things,” Banerjee said. “And this was a perfect example of where research in one field helps another. Oil field stuff came together with battery stuff and some knowledge we had about fusion.”

“We weren’t working towards this goal,” Ezazi added. “But everything that we’ve been doing has sort of been carefully aligning this trajectory for us to just find and really exploit.”

What’s next

With their lab-made proof of concept showing real promise, the team is already focused on bringing the design to market. In Switzerland, Banerjee’s team is refining the technology, while Ezazi, back in Texas, is at the helm of business-related planning.

“The primary goal that we have right now is to really advance this sort of isotope separation technology to provide high-purity lithium-6 and -7 for fission and fusion applications and supply chain dynamics,” Ezazi explained.

“The timing seems so perfect—it’s springtime for nuclear energy,” Banerjee said. “So there’s a sense of optimism that comes sometimes only right where you say, ‘I’m at the right place at the right time, and I have the right people I can work with.”

The Team

The research team includes Sarbajit Banerjee from ETH Zurich; Andrew A. Ezazi, Harris Kohl, J. Luis Carrillo, Saul Perez-Beltran, Carlos A. Larriuz, Jaime A. Ayala, Arnab Maji, and Stanislav Verkhoturov from Texas A&M University; Mohammed Al-Hashimi and Hassan Bazzi from Hamad Bin Khalifa University in Qatar; Conan Weiland, Cherno Jaye, and Daniel A. Fischer from the Material Measurement Laboratory at NIST; and Lucia Zuin and Jian Wang from Canadian Light Source Inc.

Click here to see all of the winners of the 2025 Gizmodo Science Fair.