Deciphering Interphase Reactions in Solid-state Batteries

High-performance, long-lasting, temperature-resistant and even safer: The potential of solid-state batteries is enormous. However, they can only reach technological and market readiness if all mechanisms inside the cells are precisely understood. In particular, reactions at the interphases between the solid electrolyte and the electrode can influence the stability and performance of the batteries. A team from MEET Battery Research Center at the University of Münster and the American Lawrence Berkeley National Laboratory has therefore investigated the reaction mechanisms at exactly these interphases in detail.

Reactions at the Interphase Unequally Distributed

The research team analyzed the interphase between a solid electrolyte based on lithium aluminum germanium phosphate (LAGP) and a copper electrode. “With in operando Raman spectroscopy, we used an innovative approach to precisely observe the processes within the cells,” says MEET scientist Ineke Weich. The researchers discovered that the reactions at the interphase do not occur consistently across the entire surface, but are concentrated in local hotspots – even though the LAGP was mixed homogeneously. “Such local inhomogeneities can lead to unbalanced current density distributions and the formation of reaction centers. These in turn can result in decomposition reactions, volume changes and cracks in the electrolyte, which substantially affects the performance of the batteries,” explains Weich. A detailed understanding of these processes at the interphase are therefore necessary in order to develop strategies to improve the stability and lifetime of solid-state batteries.

The chemist traveled to Berkeley for the study to work with her colleagues on site. “I had the opportunity to transfer my theoretical knowledge into practice and at the same time get to know new methods, technologies and research approaches,” reports Weich on her experiences. “Being able to work abroad not only pushed my research forward, I also gained differentiated insights into other cultures, mindsets and working practices.”

Detailed Results Online Available

The entire study has been published by the authors Ineke Weich and Dr Johannes Kasnatscheew, MEET Battery Research Center, Dr Andrew Dopilka und Prof. Dr Robert Kostecki, Lawrence Berkeley National Laboratory, as well as Prof. Dr Martin Winter, MEET Battery Research Center and Helmholtz Institute Münster, in the journal “Chemical Communications”.