2023-07-16 18:10:22
Lithium is becoming the new gold, with its demand exploding in lithium-ion batteries in electric cars, computers and portable devices, driving up prices and affecting the supply of this relatively rare metal.
Scientists are on the verge of developing a way to use sodium to replace some of the lithium, reducing costs and securing supply.
Vers des batteries sodium-lithium
Recently, scientists have considered doing without lithium altogether and instead using sodium or other elements in high-quality batteries. Sodium is cheaper and more available (it is found in seawater, as sodium chloride), but it has drawbacks. Lithium batteries remain the best for providing the charge needed to power cars and portable devices.
The doctoral student Tullio Geraci and the Professor Alexandra Navrotsky of the’Arizona State University have taken a different approach: mixing lithium and sodium in the same battery. This promises to facilitate sourcing and pave the way for cheaper batteries and a more secure supply chain.
Characterization of lithium-sodium materials
Researchers use a specialized technique developed and optimized in Navrotsky’s lab (calorimetry of high-temperature molten oxide solutions) to measure the energy stability of materials, while heating experiments determine their possible decomposition in use.
Presenting his findings at the Goldschmidt Geochemistry Conference, Tullio Geraci said : “We mixed small amounts of sodium with lithium, and tested its stability, then observed its performance. It’s a step-by-step process, and at first the stability wasn’t promising – the first thing we need is to see if the mix stays in a usable form. But as we increased the sodium content, the stability improved. So far we’ve reached 10% mixing, and it looks good, it’s still thermodynamically stable. We think we can push it up to around 20% before we see a significant difference in performance.“.
Tullio Geraci has followed : “At first, we weren’t sure if these Li/Na dilutions might even be done. Surprisingly, we found that low dilutions tend to break down, solutions lose their homogeneity and crystal structure which is important to produce a battery. But as we increase the amount of sodium, the material becomes more stable. After arriving at the optimum mix, we need to pass our findings on to battery technicians to produce the first sodium-lithium batteries. We believe these are the first steps in the development of new battery technology“.
Commenting on this work, Professor Nancy Ross (Department of Geosciences, Virginia Tech, Blacksburg VA) concluded: “Geraci and Navrotsky’s research highlights how geochemistry can be applied to the development of new materials of technological significance. Their work opens a promising avenue for exploring alternative, more affordable and sustainable sources for the lithium batteries we depend on in our daily lives.“
Synthetic
This research paves the way for the development of sodium-lithium batteries, combining the advantages of both elements for better performance and lower cost, while securing the supply of lithium.
For a better understanding
Why mix sodium and lithium?
Lithium is rare and expensive. Sodium is more abundant and less expensive. Combining the two reduces costs while maintaining the performance of lithium.
They created lithium-sodium materials at different concentrations and measured their stability. They found that a 10-20% sodium mixture was optimal.
What are the next steps ?
Transmit these results to manufacturers to develop the first commercial sodium-lithium batteries.
The Goldschmidt Conference is the world’s leading conference on geochemistry. It is a joint congress of the European Geochemical Association and the Geochemical Society (USA). It is held in Lyon, France, from July 9 to 14. Nearly 5,000 delegates are expected.7
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