Scientists use CT scanning to find out the real reason why the battery performance declines

(Image source: me.gatech.edu)

Solid-state batteries are a new type of battery design that can utilize all solid-state components. They have been attracting much attention in recent years because of their high energy storage and safety compared to liquid batteries. However, it is not easy to create durable solid-state batteries. According to foreign media reports, researchers at the Georgia Institute of Technology (George Tech) in the United States used X-ray computed tomography (CT) to observe how cracks are generated near the material interface inside the battery. Scientists use these findings to find new ways to enhance energy storage devices.

The research was funded by the National Science Foundation. The researchers built a new solid-state battery with a solid ceramic disk as the electrolyte, tightly sandwiched between two sheets of solid lithium. The scientists worked with Christopher Saldana, an X-ray imaging expert at the Georgia Institute of Technology, to place the solid-state battery under an X-ray microscope and then began charging and discharging it to observe signs of physical degradation. Over a period of several days, a network of cracks gradually formed on the ceramic disk. The researchers found that these cracks were the problem, blocking the flow of ions during the cycle.

Matthew McDowell, an assistant professor at Georgia Institute of Technology, said that people usually think that the chemical reaction at the interface of lithium metal and electrolyte is the reason for the decline in battery performance. Now through imaging, we can know that in this special material, it is not the chemical reaction itself that affects the battery performance, but the cracks inside the battery. The researchers believe that this discovery is also applicable to other types of solid-state batteries and will help create more durable battery structures.

“In regular lithium-ion batteries, the materials we use determine how much energy we can store,” McDowell said. “Pure lithium has the most, but it doesn’t combine well with liquid electrolytes. But if you take solid lithium and a solid electrolyte, that’s the holy grail of energy density.”

Now, researchers at Georgia Tech are designing a new battery that is made entirely of solid materials and is safer and has higher energy density than traditional batteries.