Under the Skin: How Electric Vehicle Researchers Are Chasing Material Gains Car News

It may come as no surprise, but the global electric vehicle boom is driving furious activity in battery development.

Work is underway to improve existing lithium-ion technology (such as solid-state batteries that do away with liquid electrolyte), but determined efforts are also being made to perfect the use of more diverse ingredients. Most are still in the research stage, and while it is true that attempts to develop better batteries in the past have yielded nothing tangible, there is now much more incentive and financial support. to try to make game-changing ideas work.

One of them is the lithium air cell, a kind of halfway house between a conventional battery and a hydrogen fuel cell. The man who really got the ball rolling on lithium air cells is Professor Peter Bruce, a chemist who successfully prototyped a single lithium air cell in a four-year project that spanned ran from 2007 to 2011 at the University of St Andrews. Lithium air cells use oxygen from the air as part of the chemical reaction that occurs during charging and recharging, eliminating the need to carry chemicals into the battery.

Success would mean greater capacity than we have today, but overcoming a lack of efficiency and low life (the number of charges and discharges a battery can take before it begins to degrade) proved difficult to overcome beyond double digits. That said, scientists around the world are still on the case, and earlier this year researchers from Japan’s National Institute of Materials Science (NIMS) claimed to have developed a lithium-air battery with a density of energy of 500 Wh per kilogram, about twice that of the best lithium-ion batteries. However, no mention was made of how many charge and discharge cycles it can achieve.

Scientists at the Illinois Institute of Technology said last year they had overcome the problem, after completing 1,200 charge and discharge cycles in a prototype battery. The reduced lifetime is due to the other elements in the air, such as carbon, nitrogen and water, which also react with the lithium and produce a contaminant layer which prevents oxygen from reaching the electrode positive and deplete the lithium. The team developed an electrolyte that prevents this from happening and absorbs any impurities.

Other technologies are also accelerating. Battery start-up Theion, whose CEO Ulrich Ehmes is experienced in industrializing battery production, has developed a lithium-sulfur positive electrode (cathode) that it claims can triple the range given by cells conventional lithium ions. Sulfur is an abundant element and in this case replaces nickel and cobalt. The use of cobalt in batteries is controversial due to the environmental impact of the waste generated by its extraction, not to mention the associated human cost.

Theion claims that its sulfur-based technology is 99% cheaper to purchase and that manufacturing battery cells using it consumes 99% less energy. The company says 16 patents are pending on processes for making the cathodes for what it calls its “Crystal Battery,” based on the fact that sulfur exists naturally in crystal form. Theion will build and supply batteries for testing by aerospace customers this year. Automotive use is planned for 2024 and gigafactory-scale production by 2025.