Molten Salt Solutions lands $7 Million to build a US commercial lithium-6 source

Molten Salt Solutions’ new funding is aimed at converting laboratory-validated separation chemistry into pilot-scale output over the next two years

(Image courtesy of Molten Salt Solutions)

Molten Salt Solutions has closed an oversubscribed $7 million seed round to scale production of enriched lithium-6 and lithium-7, the isotopes fusion and advanced fission developers need for tritium breeding and reactor coolant systems. Dolby Family Ventures led the round, joined by Vanedge Capital Partners, Alumni Ventures, Gaingels, True Ventures, and Future Ventures. For a supply chain that still has no domestic commercial enrichment source, the raise is a concrete step toward closing that gap.

The round follows a $3 million pre-seed raise in December 2024, more than $5 million in grant funding including New Mexico’s Advanced Energy Award, and a 2025 Department of Energy INFUSE award that funded fusion-grade lithium specification work with Los Alamos National Laboratory, the University of New Mexico, and Element 3 Energy.

Why domestic lithium-6 supply matters for fusion developers

Lithium-6 makes up roughly 7.5% of natural lithium, a small enough share that tritium-breeding systems depend on the enriched form to work at all, according to the Department of Energy. Producing it at scale has historically been the domain of national weapons programmes, and today only Russia and China operate commercial-scale enrichment capacity for both lithium-6 and lithium-7, supply that is not available to Western reactor developers, according to trade publication Nuclear Engineering International. A domestic source changes that picture for developers who will need increasing volumes as their programmes move from testing toward deployment.

MSS says its platform addresses that gap with an integrated solvent exchange process, replacing the thousands of separate processing stages the legacy chemical exchange method requires. Richard Pearson, co-founder of Kyoto Fusioneering, has projected that fusion pilot plants will eventually require tens of tonnes of enriched lithium-6, rising to hundreds of tonnes at commercial scale, according to Nuclear Engineering International.

Where near-term demand is coming from

Molten Salt Solutions has established frameworks with Type One Energy and Gauss Fusion to explore future lithium supply, anticipating initial kilogram-scale deliveries for testing as early as 2027 and potential expansion to several hundred tonnes as those companies move toward their first power plants. MSS’s agreement with Fissionaire, signed separately in June 2026, sits on firmer ground: it’s a commercial agreement to supply lithium-7, with early deliveries at test-scale quantities targeted for 2028 and volumes expanding to multi-tonne levels as that programme advances.

Lithium-7 serves a different purpose than lithium-6. It limits neutron absorption and tritium formation in certain reactor coolants, a property advanced fission developers depend on much as fusion developers depend on lithium-6 for breeding.

From grant-funded research to funded production

MSS says the new capital will expand its technical and operations teams and deepen partnerships across the fusion and advanced nuclear supply chain, on top of moving toward pilot-scale output. Between the Type One Energy and Gauss Fusion framework and the Fissionaire agreement, the company has a clearer map of near-term demand than it did a year ago, with pilot-scale delivery now the next test.

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