A collaboration among researchers at Vanderbilt University (Nashville, Tenn.), the University of Pennsylvania, (Philadelphia), the Advanced Photon Source, (Lemont, Ill.), and Toyota Research Institute North America (TRINA), a division of Toyota Motor North America R&D (Ann Arbor, Mich.), examined operating limits and failure mechanisms in a family of solid-state batteries based on thiophosphate materials.
There is huge momentum toward adopting electric vehicles (EVs) with batteries primarily because performances are meeting or exceeding the properties of traditional automobiles. Consumers want electric vehicles that have similar driving range (energy density) and charging styles and times (power density) to gasoline-powered vehicles.
“One pathway to improving the energy density of the battery, or the driving range, is to move toward solid-state batteries. Solid state batteries eliminate all liquids and thus have smaller form factors and can potentially integrate energy dense alkali metals,” says Kelsey Hatzell, assistant professor of mechanical engineering and a Flowers Family Faculty Fellow in Engineering.
The team used advanced in-situ synchrotron x-ray tomography and in-situ transmission electron microscopy to look into solid state batteries while cycling lithium ions through the solid electrolyte. The work identified preferential ion movement, known as current focusing, as the predominant pathways for fracture in these solid-state systems.
This work provides a basis for understanding materials design and system engineering approaches that can facilitate high rate, or high power density, operating regimes. For batteries to fully displace the current state of the art, using materials that can achieve long distances, fast charging, and safety are key.
The work was co-led by Marm Dixit, a Ph.D. candidate in mechanical engineering, and Nik Singh, a senior scientist in the Materials Research Department at TRINA. This collaboration is a result of Hatzell’s ECS/Toyota Fellowship and a collaboration with Tim Arthur, principal scientist in the Materials Research Department at TRINA.
“To realize batteries that can drive longer on a single charge, we have to design them over cascading length scales–from nanometer levels to the mesoscale. This work was very exciting as we investigate the battery over these vast length scales with advanced characterization methods and help identify pathways to better batteries,” Marm said.
The paper—“In situ Investigation of Chemomechanical Effects in Thiophosphate Solid Electrolytes”—was published in Cell Press journal Matter.
For more information:
Advanced Photon Source
https://www.aps.anl.gov/
Toyota Research Institute
https://www.tri.global/
University of Pennsylvania
https://www.upenn.edu/
Vanderbilt University
https://www.vanderbilt.edu/
