Solid-state battery: New material class with excellent ion conductivity

February 15, 2023

A research team at the Technical University of Munich (TUM) has discovered a material class with above-average conductivity. This is a decisive step forward in the development of high-performance solid-state batteries. In contrast, the electrolyte in solid-state batteries is a solid substance which can neither leak nor burn. In addition, this solid electrolyte helps reduce the battery weight, making it theoretically an ideal alternative. Our objective was to better understand ion transport and then to use this knowledge to increase conductivity."

A research team at the Technical University of Munich (TUM) has discovered a material class with above-average conductivity. This is a decisive step forward in the development of high-performance solid-state batteries. Investigations conducted at the Research Neutron Source Heinz Maier-Leibnitz (FRM II) made an essential contribution to the discovery.

The batteries of the future will have to satisfy high expectations: They will have to be lighter and perform better, have longer service lives, be safer and also less error-prone. Scientists around the world are pursuing these objectives using solid-state technologies: Solid-state batteries contain no liquid, in contrast to traditional rechargeable batteries in which lithium ions move through a liquid electrolyte from the anode to the cathode and back again. In contrast, the electrolyte in solid-state batteries is a solid substance which can neither leak nor burn. In addition, this solid electrolyte helps reduce the battery weight, making it theoretically an ideal alternative.

"But in practice the solid-state electrolytes available up to now, mostly oxidic ceramics or compounds based on sulfur, have proven unable to completely meet expectations," says Prof. Thomas Fässler of the TUM Professorship for Inorganic Chemistry with Focus on New Materials. Together with his team and in close cooperation with TUMint·Energy Research GmbH, he is looking for more efficient electrolytes: "The problem is that lithium ions only diffuse slowly through solid materials. Our objective was to better understand ion transport and then to use this knowledge to increase conductivity."