Making safer and more conductive lithium batteries

Virginia Commonwealth University researchers are working to improve conductivity and safety in lithium-ion batteries, which are used to power many electronic devices around the world, including laptops, iPods, satellites, artificial hearts and cell phones.

To improve the conductivity in solid-state electrolytes, the researchers produced a computational model in which a single negative ion is removed. Negative cluster ions — groups of atoms with more electrons than protons — replace the absent ion.

The scientists conceptualized a twist on a specific solid-state electrolyte previously tested by other researchers. Originally, the electrolyte, which belongs to a family of crystals called antiperovskites, contained positive ions made of three lithium atoms and one oxygen atom. The positive ions were joined with a single chlorine atom that was a negative ion.

In the computational model, the chlorine atom is replaced by a negative cluster ion created by one boron atom and four fluorine atoms joined to the existing positive ions.

Other combinations of negative cluster ions were identified to potentially enhance conductivity.

“Replacing the chlorine ion with cluster ions improves conductivity because these ions are larger and allow the lithium ions to move quickly, as if they were in a liquid,” Fang said.

PNAS – Li-rich antiperovskite superionic conductors based on cluster ions