A new way of observing materials could accelerate the development of new batteries.
Solid-state batteries replace the usual liquid with a solid material; they are less flammable and could store more energy. But their efficiency depends on a crucial element: the ability of ions to move quickly inside the solid.
Mobile ions (in orange) move through the atomic structure of a sodium-based solid electrolyte.
Credit: Dr. Manuel Grumet, Dr. Waldemar Kaiser from the Technical University of Munich
Finding the right materials remains complicated. Testing each candidate requires time and heavy calculations, and simulating the movement of ions precisely, especially at high temperature, demands a lot of computing power.
An original approach involves observing the light scattered by these materials. When ions move freely, they slightly disturb the organization of atoms. This agitation leaves a particular signature in the analyzed light, called Raman spectrum. The researchers combined this idea with artificial intelligence. Their models are capable of predicting these light signatures without simulating every detail. Result: much faster and less expensive calculations.
By testing their method on materials containing sodium, the scientists identified a clear clue: when ions circulate easily, intense signals appear at low frequency in the Raman spectrum. Conversely, when ions are more limited in their movements, these signals are absent. This difference allows for quickly distinguishing good conductors from less performant materials.
More broadly, this method creates a direct link between numerical simulations and real experiments. It allows for efficiently preselecting materials even before their fabrication. The objective is clear: accelerate the discovery of high-performance solid electrolytes. This could promote the development of safer, more durable batteries offering better autonomy.