Fusion uses 6Li, which is only a minor fraction of natural lithium. The 7Li (93% of the element) can be used in batteries just fine.
At one point back in the 1960s some physicists were trying to make a neutron detector using lithium, and it wouldn't work. They eventually discovered the lithium they had purchased from a chemical supply company was nearly pure 7Li. It had been sold back into the chemical market from the waste stream of the government's lithium enrichment facility.
At one point back in the 1960s some physicists were trying to make a neutron detector using lithium, and it wouldn't work. They eventually discovered the lithium they had purchased from a chemical supply company was nearly pure 7Li. It had been sold back into the chemical market from the waste stream of the government's lithium enrichment facility.