A major breakthrough in nuclear energy has been made thanks to an impossible fuel that was discovered by mistake. Nuclear fusion has long been considered the holy grail of energy, with near-limitless capabilities, but the door has been firmly shut for decades as scientists try to find the master key. Recently, a team of researchers stumbled upon a way to isolate a key chemical without releasing toxic mercury into the environment.
The impossible fuel that could change everything
Famous American painter Bob Ross once said, “We don’t make mistakes, just happy accidents,” and researchers at ETH Zürich and Texas A&M University may have made the happiest accident of all. In the hunt to achieve nuclear fusion, a major stumbling block has been the isolation of lithium-6, but that may be a headache of the past.
One of the oldest but most effective ways to source lithium-6 was called the COLEX process, and it involved separating lithium-6 and lithium-7 using mercury. The name COLEX is short for column exchange, and its invention is credited to Forrest Waldrop, who happened to work on the Manhattan Project.
The issue with COLEX, and why it was banned in 1963, is that it released toxic mercury back into the environment. Now, if you want to use lithium-6 for research purposes in the USA, you’ll have to get it from a limited supply at the Oak Ridge National Laboratory in Tennessee.
The science behind the fuel of the future
Nuclear fusion reactors fuse deuterium and tritium atoms. The two heavy forms of hydrogen helped give the Tsar Bomba a yield of 50 megatons of TNT and the title of most powerful nuclear weapon in history. Fusion reactors seek to harness that massive amount of energy to produce electrical power.
The tritium used in fusion reactors is extremely scarce but can be sourced from lithium-6. The issue is that two kilograms of lithium-6 are needed to produce one kilogram of tritium. Long story short, to make nuclear fusion reactors a viable reality, you need a bunch of lithium-6.
There’s plenty of natural lithium around; ask Australia and Chile, but the COLEX process is banned. Luckily, the aforementioned researchers in Texas found a new method without even trying to while developing membranes that can clean the water that comes to the surface in oil and gas fracking operations.
Making your own luck with water and lithium
The membranes they developed were capturing lithium in the water, and the researchers had a eureka moment. A material called zeta-vanadium oxide (ζ-V₂O₅) was the key, and positively charged lithium 6 ions were caught in the one-dimensional tunnels of the negatively charged zeta-vanadium oxide electrode.
Chemist and senior author Sarbajit Banerjee of ETH Zürich and Texas A&M University explained further by stating,
“That led us to wonder whether this material might also have some selectivity for the 6-lithium isotope. Zeta-V2O5 has some pretty incredible properties—it’s an amazing battery material, and now we’re finding that it can trap lithium very selectively, even with isotopic selectivity.”
The discovery led the researchers to find that one electrochemical cycle could enrich the lithium-6 by 5.7%. But to produce fusion-grade lithium (which needs at least 30% lithium-6), they would need to repeat the process 25 times. Impressively, 90% lithium-6 could be achieved with 45 sequential cycles.
The next steps are quite difficult; the team needs to find a way to scale the new process up to the industrial level, and this only represents one piece of the nuclear fusion puzzle. However, with global interest in the potential of endless green energy, there is sure to be a domino effect in the field of nuclear research. It won’t be too long before the potential of nuclear fusion reactors is realized.