Munich research team improves lithium-ion conductors for solid-state batteries

The Technical University of Munich reports a world record for lithium-ion conductors, marking an important step in improving solid-state batteries: Scientists at TUM and TUMint.Energy Research GmbH have developed a new material made of lithium, antimony, and scandium that, according to the press release, conducts lithium ions over 30 percent faster than any previously known material. Solid-state batteries are considered an important future technology because they can store more energy than current lithium batteries and are not made of flammable materials.

Specifically, the team led by Thomas F. Fässler from the Chair of Inorganic Chemistry with a focus on new materials replaced part of the lithium in the lithium antimonide compound with the metal scandium. This deliberately created gaps, so-called vacancies, in the crystal lattice of the conductor material. These allow the lithium ions to move more easily and quickly. Because the achieved value is so significantly higher than that of known materials, the TUM Chair of Technical Electrochemistry led by Hubert Gasteiger confirmed the result.

“Our result currently represents a significant advance in basic research. By incorporating small amounts of scandium, we have discovered a new principle that could prove groundbreaking for other element combinations,” says Thomas F. Fässler. He sees great potential for the new material, even though much testing is still necessary for its application in a battery cell. “We are confident because materials that can conduct both ions and electrons are particularly well suited as additives in electrodes.”

In addition to the increased speed, the material also offers thermal stability and is easy to manufacture using proven chemical processes. Since this could lead to promising practical applications, a patent application has already been filed for the development.

As lead author Jingwen Jiang from TUMint.Energy Research GmbH emphasizes, a completely new class of substances was discovered during the research. “Our combination consists of lithium-antimony and can easily be transferred to lithium-phosphorus. While the previous record holder was based on lithium-sulfur and required five additional elements for optimization, ours requires only scandium as an additional component. We assume that our discovery may have significance beyond this example for increasing the conductivity of other substances.”

The scientists have published the detailed results in Advanced Energy Materials under the title ” Scandium Induced Structural Disorder and Vacancy Engineering in Li3Sb – Superior Ionic Conductivity in Li3−3xScxSbv .”