Licube, a startup licensing technology from Japan’s Hirosaki University, is developing a method to separate lithium-6 from naturally occurring lithium for use in nuclear fusion reactors. The company aims to address a potential shortage of lithium-6, a material needed to produce tritium fuel, which many planned fusion power plants will require to operate.
Licube co-founder and CEO Yohei Kiguchi estimates that the lithium-6 market for fusion energy could reach $50 billion by 2040 if commercial fusion power becomes widely available. The startup is among 20 companies competing in TechCrunch Disrupt 2026’s Startup Battlefield competition in San Francisco.
Why Fusion Reactors Need Lithium-6
Most proposed fusion power plants use deuterium and tritium as fuel to generate energy. While deuterium is relatively abundant, tritium is extremely scarce in nature, creating a potential supply problem for companies developing commercial reactors.
To address the shortage, fusion developers plan to surround their reactors with lithium-containing blankets that capture neutrons released during fusion reactions. When neutrons interact with lithium-6, they can produce tritium and helium, allowing the recovered tritium to be processed and reused as reactor fuel.
However, lithium-6 accounts for only approximately 7.5% of naturally occurring lithium, with most of the remainder consisting of lithium-7. Separating the two isotopes is technically challenging, and existing production capacity remains limited.
How Licube’s Lithium Purification Technology Works
Licube uses an electrochemical separation process developed through research at Hirosaki University. The system passes an electrical current through a ceramic membrane separating lithium-containing liquids, allowing lithium-6 to move through the membrane faster than lithium-7.
This difference in movement allows the company to progressively concentrate lithium-6 for industrial applications. According to Licube’s technology information, the process is intended to provide an alternative to conventional isotope separation methods that use toxic mercury.
The company’s target is to produce lithium enriched to at least 99.995% lithium-6 for fusion fuel systems. Such material could be used in the lithium blankets designed to produce tritium inside commercial fusion reactors.
Licube Targets Other Industries Before Fusion Commercialization
Licube also plans to supply purified lithium to semiconductor manufacturers, pharmaceutical companies, nuclear fission operators, and aerospace businesses. These markets could provide revenue while commercial fusion power plants remain under development.
The company has already opened preorders for 99.99% pure lithium hydroxide, a separate product intended for high-purity industrial applications. Its lithium-6 enrichment technology remains under research and development.
Kiguchi founded Licube after visiting ITER, the experimental fusion reactor under construction in southern France. He previously established Enechange, a Japanese energy-switching platform, before retiring and relocating to Monaco.
The visit prompted Kiguchi to return to the energy industry and pursue lithium purification technology. He acknowledged that commercial fusion deployment could take longer than expected, making other industrial customers important to Licube’s development plans.
Featured image credits: Wikimedia Commons
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