Solid-state batteries promise to outperform lithium-ion batteries in electric vehicles by, among other things, providing faster charging times and overall longer life spans. But flaws in solid-state batteries have hampered efforts to achieve this advantage. 

Now, in a paper recently published in Nature Materials, Kelsey Hatzell, assistant professor in mechanical and aerospace engineering and the Andlinger Center for Energy and the Environment, and her colleagues have isolated an important flaw in solid-state batteries. They discovered that irregularities in the crystals that make up the battery's electrolyte -- the battery's core -- cause ions to move at different rates throughout the battery, accelerating battery failure. 

She likened the movement of charged ions through the battery to water moving down a river and encountering a rock that redirects the water. “If you have all the ions going to one location, it is going to cause rapid failure,” Hatzell said. “We need to have control over where and how ions move in electrolytes in order to build batteries that will last for thousands of charging cycles.”

The researchers conclude, however, that it should be possible to solve this flaw in the battery's reliability by adjusting material processing and manufacturing approaches. 

“We have a lot of hypotheses that are untested of how you would avoid these heterogeneities,” Hatzell said. “It is certainly going to be challenging, but not impossible.”