Fusion Materials Startup Molten Salt Solutions Lands Two New Buyers

It isn’t every day that an investor sends an unsolicited reach-out to an early-stage startup with no venture funding to its name. But a few years ago, that’s what happened to John Elling, CEO and co-founder of Molten Salt Solutions, a startup producing lithium isotopes for the fusion and fission supply chains. At first he assumed the email from Future Ventures was a scam. But when the investor explained that her firm was looking to derisk its stake in leading fusion company Commonwealth Fusion Systems by securing a supply of the isotope lithium-6 — which is critical to the production of fusion fuel — he figured he should hear her out.

“I’ve been an entrepreneur for 28 years, and it’s the first time I’ve ever had a cold call from a VC,” Elling told me. “So I answer the email and darn if they don’t invest in us.” That initial $3 million seed round came in 2024. And while Molten Salt Solutions doesn’t yet have an official tie-up with Commonwealth, Heatmap can report exclusively that it has signed nonbinding strategic sales agreements with two other fusion startups, Type One Energy and Gauss Fusion.

This isn’t Elling’s first startup rodeo. A former scientist at Los Alamos National Laboratory, he left in 1998 and embarked on a string of ventures to commercialize technologies rooted in the lab’s research. Molten Salt Solutions, which he founded in 2018, also built upon breakthroughs in the lab in pursuit of producing lithium-6 for the fusion industry and lithium-7 for next-generation molten salt fission reactors, where the isotope is a critical component of the reactor’s coolant.

Securing enriched isotopes is a bottleneck for both industries due to the technical challenges, high cost, and limited infrastructure for traditional methods of lithium enrichment. But Elling has managed to woo several national lab alumni and top scientists out of retirement to commercialize what he describes as a highly efficient, cost-effective method of separating and purifying these isotopes. “We have people who retired at the pinnacle of their career at Los Alamos who are gleefully back doing grad student research tasks, washing out test tubes and setting up reactions in the lab,” Elling told me.

The core of Molten Salt Solutions’ separation technology — solvent exchange — is a well-established industrial process that moves lithium ions between a water-based layer and an organic layer. Because lithium-6 ever so slightly favors the organic layer, while lithium-7 prefers the water layer, repeated cycles gradually concentrate the isotopes in their preferred regions. But since lithium-6 makes up only about 7.5% of naturally occurring lithium, the process typically must be repeated thousands of times to enrich the isotope to the desired level. That’s how you end up with enrichment facilities “the size of football fields” Elling explained.

To avoid that, Molten Salt Solutions — which Elling admits isn’t really focused on making molten salts at all these days — is commercializing a technique called high-speed countercurrent chromatography. This approach, which has been largely confined to the lab for decades, uses centrifugal force to rapidly separate the water and organic layers, effectively performing in a single, integrated system what would normally require hundreds of discrete steps. Elling told me that adapting this process for lithium isotopes required gaining a deeper understanding of the device’s physics than had previously been appreciated, allowing his team to redesign the system for its purposes.

If all goes according to plan, Molten Salt Solutions will begin supplying kilograms of lithium isotopes to Type One Energy and Gauss Fusion in 2027, with the goal of scaling to hundreds of tons as the startups conduct larger-scale testing and, ideally, bring their first commercial power plants online in the early- to mid-2030s. But even meeting these two startups’ more near-term research needs will require rapid growth. Molten Salt Solutions is now looking to hire engineers to scale its technology for commercial production and move from its current Sante Fe research facility to a larger space.

Down the road — or perhaps even as a backup plan should a fusion energy industry fail to materialize — the company’s tech could be used for a variety of purposes beyond nuclear energy — namely the production of medical isotopes used for diagnostic imaging. Some fusion companies, such as Shine Technologies and Avalanche Energy, are already incorporating medical isotopes into their revenue strategies as commercial fusion remains a goal for the 2030s and beyond.

But assuming both fusion and next-generation fission reactors do eventually take off, the market opportunity for Molten Salt Solutions’ humble isotopes is enormous, as securing a cheap supply of these materials could materially lower the cost of building reactors. “It's one of those marquee problems that you can work on in your scientific career,” Elling told me. “Because you look down the road and you go, you know, we could actually change the price of energy on the globe.”