If fusion power pans out, and there are signs that it will, the world will need a lot more lithium.
That’s the bet behind Licube, a startup that has licensed technology from Hirosaki University in Japan, to purify lithium-6, the form of lithium that fusion plants need to make their own fuel, out of naturally occurring lithium.
The reason comes down to the fuel supply. A lot of things have to go right for fusion power to hit the grid, and one of them is the fuel. Most planned plants would run on a mix of two fuels, deuterium and tritium. Deuterium is easy to come by, but tritium is extremely rare in nature, and it’s an open secret in the fusion world that there isn’t enough of it to power every planned plant.
The proposed workaround is to make tritium on site, inside the power plant itself. A fusion reaction gives off a stream of fast-moving particles called neutrons. Startups plan to surround the reactor with a blanket of lithium, so that when a neutron strikes a lithium atom, the atom splits into helium and tritium. The tritium can then be collected, purified, and fed back into the reactor as fuel.
Not all lithium does this job equally well. It comes in two slightly different forms, lithium-6 and lithium-7, named for their weights. Lithium-6 is far better at capturing neutrons and producing tritium, but it makes up only about 7.5% of natural lithium, and the rest is the heavier lithium-7. Separating the two is difficult, and there is little capacity to do it today, so the world doesn’t have enough lithium-6 either.
Licube sees a big market in solving that problem. “If fusion comes online, it should be a $50 billion market by 2040,” Yohei Kiguchi, co-founder and CEO of Licube, told TechCrunch.
Licube is one of 20 startups that are presenting onstage at TechCrunch Disrupt in San Francisco as part of the Startup Battlefield pitch competition.
While fusion has the potential to capture a significant chunk of the multitrillion-dollar energy market, fusion startups are still years away from building their first power plants.
“Fusion is the biggest market in the future, but we also understand the future might be late by a few years,” Kiguchi said.
Until fusion becomes a major market, Licube plans to use the same technology to purify lithium for use in semiconductor, pharmaceutical, fission reactors, and spacecraft industries.
The core technology is based on the electrolyzer, a device that uses electrical current to drive chemical reactions. In Licube’s case, lithium is dissolved in a liquid on one side of a ceramic membrane. As electrical current flows from one side of the membrane to the other, lithium-6 moves faster. Licube can then draw off that liquid and separate the lithium-6.
The goal is to enrich the lithium to at least 99.995% lithium-6. Fusion companies can feed that highly enriched lithium into their fuel breeding systems.
Kiguchi was inspired to start Licube after visiting ITER, the experimental fusion reactor being built in the south of France. He said he was living a couple of hours’ drive away in Monaco after retiring from his previous company, Enechange, an energy-switching platform network in Japan.
“I found out that I was too young to retire,” he said. “I’m an energy guy. I want to do something bigger.”