The potential of fusion energy lies in providing cheap and abundant power globally. Scientists have made significant strides towards realizing this potential on a large scale, yet challenges remain, particularly in the production of enriched lithium fuel. The process of lithium enrichment has historically caused environmental damage, but a team of researchers in Texas claims to have developed a more environmentally friendly and cost-effective method.
This discovery was made by accident at Texas A&M University while a team was working on a method to clean groundwater tainted during oil and gas extraction. Their findings have been published in the journal Chem under the title “Electrochemical 6-Lithium Isotope Enrichment Based on Selective Insertion in 1D Tunnel-Structured V2O5.”
The implications of this research could be significant for nuclear fusion. Sarbajit Banerjee, a professor and researcher at ETH Zürich and Texas A&M, and one of the paper’s authors, explained that nuclear fusion is the primary energy source for stars like the Sun. The simplest method to achieve fusion on Earth involves tritium and deuterium isotopes. Currently, tritium, being rare and radioactive, is produced on demand in reactors to generate energy.
The production involves bombarding lithium isotopes with neutrons to breed tritium. Most of Earth’s lithium, over 90%, is lithium-7, but the process is more efficient with the rare lithium-6. Banerjee noted that when lithium-7, the more common isotope, is used, tritium production is less efficient compared to lithium-6. Modern reactors, therefore, integrate breeding blankets enriched with lithium-6, which must be extracted from natural lithium.
While lithium enrichment is possible, the method has been environmentally hazardous. From 1955 to 1963, the United States produced lithium-6 at the Y-12 plant in Oak Ridge, Tennessee, using the solubility difference between isotopes in liquid mercury. Banerjee pointed out that this process resulted in approximately 330 tons of mercury being released into waterways, which was a significant environmental disaster, affecting the region to this day. The cleanup of this area remains a major project for Oak Ridge National Laboratory.
During another project, the Texas A&M team developed a compound named zeta-V2O5 to clean groundwater. This compound proved effective at isolating lithium-6 from lithium isotope mixtures without the use of mercury. “Our approach utilizes the core functionalities of lithium-ion batteries and desalination technologies,” stated Banerjee. By inserting lithium ions into the one-dimensional tunnels of zeta-V2O5 from flowing water streams, the process demonstrated a preference for lithium-6, providing a safer isotope extraction method.
This new method could significantly impact the development of fuel for fusion generators without necessitating a complete redesign of existing reactors. Banerjee emphasized that their work addresses a critical supply chain issue for fusion, but it does not involve redesigning the reactors themselves, although there is growing excitement around new innovations in plasma physics.
There is considerable interest in fusion as a potential source of affordable and abundant energy. Banerjee remains optimistic about its future, despite the current challenges. The transformative potential of fusion represents a valuable pursuit, with current efforts focusing on overcoming obstacles in engineering designs, materials science, and plasma processes. While fusion energy is not imminent, Banerjee anticipates promising developments within the next two to three decades, driven by escalating global competition and substantial investments in both private and public sectors.
