Licube aims to supply the fusion industry with purified lithium-6
A Japanese startup has licensed technology to separate lithium-6 from natural lithium, betting that fusion power plants will need massive quantities of the isotope to breed their own fuel.
Should fusion power become viable at scale, global demand for lithium will surge dramatically. Licube, a startup operating under a license from Hirosaki University in Japan, is positioning itself to meet that demand by extracting and purifying lithium-6, the specific isotope that fusion reactors require to generate their own fuel from naturally occurring lithium deposits.
The challenge stems from how fusion fuel cycles work. Most fusion plants in development would rely on a combination of deuterium and tritium as fuel. While deuterium occurs abundantly in nature, tritium is extraordinarily scarce, and the fusion industry openly acknowledges insufficient natural reserves exist to power all planned facilities.
The solution involves breeding tritium inside the reactor itself. Fusion reactions produce streams of neutrons, and designers plan to line reactors with lithium blankets. When neutrons strike lithium atoms, they split into helium and tritium, which can then be extracted, refined, and recycled back into the reactor as fuel.
However, not all lithium performs equally in this role. The element exists in two isotopic forms: lithium-6 and lithium-7, distinguished by atomic weight. Lithium-6 excels at capturing neutrons and generating tritium, yet it comprises only roughly 7.5% of naturally occurring lithium, with the remainder being the heavier lithium-7. Current global capacity to separate these isotopes remains minimal, creating a supply bottleneck.
Licube believes this gap represents a substantial commercial opportunity. "If fusion comes online, it should be a $50 billion market by 2040," said Yohei Kiguchi, the company's co-founder and CEO.
The startup is among 20 companies competing in the Startup Battlefield pitch competition at TechCrunch Disrupt in San Francisco. Though fusion holds promise as a transformative energy source with potential to capture significant market share in the multitrillion-dollar energy sector, commercial fusion plants remain years away from operation.
"Fusion is the biggest market in the future, but we also understand the future might be late by a few years," Kiguchi acknowledged.
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Before fusion becomes a major revenue driver, Licube intends to deploy its purification technology across semiconductor manufacturing, pharmaceuticals, fission reactor operations, and aerospace applications.
How the technology works
The company's approach centers on an electrolyzer, a device that uses electrical current to initiate chemical reactions. In Licube's system, lithium dissolves in liquid on one side of a ceramic membrane. As current flows across the membrane, lithium-6 ions migrate faster than lithium-7. The company can then extract and isolate the enriched lithium-6 stream.
The target enrichment level reaches at least 99.995% lithium-6 purity. Fusion operators can then feed this highly enriched material into their fuel breeding blankets.
Kiguchi's path to founding
Kiguchi's entrepreneurial journey toward Licube began with a visit to ITER, the experimental fusion reactor under construction in southern France. At the time, he was residing a short drive away in Monaco, having stepped back from his previous venture, Enechange, a Japan-based energy-switching platform network.
"I found out that I was too young to retire," he said. "I'm an energy guy. I want to do something bigger."