US researchers find heat boosts lithium-ion speed in solid-state battery material

Researchers have identified how heating the superionic conductor lithium phosphorus sulfur chloride (Li₆PS₅Cl) above 260°F (400 K) significantly enhances lithium-ion movement. By utilizing neutron scattering at Oak Ridge National Laboratory’s Spallation Neutron Source alongside computer simulations, the team observed that the material enters a superionic state where ions move through the solid structure in a manner resembling liquid electrolytes.

The study revealed that ion transport is not solely dependent on temperature. Specific vibrations within the material’s crystal framework help lithium ions navigate through narrow diffusion bottlenecks. These structural vibrations facilitate rapid hopping and long-range flow across the crystal lattice.

These findings provide a roadmap for improving the performance of solid-state batteries. By tailoring superionic conductor materials to optimize ion mobility, developers may be able to create batteries that offer the high conductivity of liquid electrolytes combined with the superior chemical and thermal stability of solid electrolytes, potentially leading to faster and safer charging.