Researchers at the University of Maryland, who are studying lithium batteries and how they fail, have developed a technology that can be used to create next-generation electric cars (EVs) as well as other devices with increased energy storage while being less susceptible to battery fires.
This innovative method is described in a paper that was published in Nature on Wednesday. It suppresses dendrite growth, which can cause damage to the branch-like structures inside all-solid-state lithium batteries. The technology has not been widely commercialized, and this prevents firms from commercializing it. This new design of a battery interlayer, led by Department of Chemical and Biomolecular Engineering professor Chunsheng Wang stops dendrites from forming. It could lead to the production of all-solid-state batteries for electric vehicles.
In the U.S., at least 750,000 EVs are registered and run on lithium-ion battery technology. These batteries are popular due to their high energy density but also contain a flammable electrolyte liquid component that can burn when heated. Electric car battery fires are relatively rare, and no government agency tracks them. However, the National Transportation Safety Board warns that they can pose a special risk.
Wang explained that while all-solid-state battery technology could make cars safer than the current models of electric and internal combustion engines, devising a strategy for overcoming their drawbacks would be difficult. These batteries can’t be operated at the high capacity and discharge rates required by electric vehicles. Lithium dendrites will grow towards the cathode, causing short circuits and a decline in power.
In 2021, he and Postdoctoral Assistant Hongli Wan developed a theory on the formation of lithium-dendrite growth. It is still a subject of debate among scientists.
He said that after figuring out the problem, he proposed a redesign of the interlayers to suppress lithium dendrite formation effectively.
The solution they have developed is unique due to the stabilizing of interfaces between the electrolyte, anode, and cathode. (This is where electrons enter the battery from circuits) The new battery structure includes a fluorine-rich interlayer to stabilize the cathode and a magnesium bismuth interlayer on the anode that suppresses lithium dendrite.
Solid-state batteries represent the next generation because they are able to achieve both high energy and safety. “In current batteries, high energy comes at the expense of safety,” Wang said.
Before the product can be sold, researchers must solve other problems. Experts will need to reduce the thickness of the solid electrolyte to a level similar to that found in lithium-ion battery electrolytes to commercialize the all-solid-state batteries. This will increase the energy density or the amount of Power the batteries can store. The team also said that the high costs of basic materials are another problem.
Solid Power, a manufacturer of advanced batteries, plans to start testing the new technology in order to evaluate its commercialization potential. Researchers said that they will continue to research ways to boost energy density.