Louisiane Verger received her PhD in Physics and Chemistry of Materials from the University Pierre and Marie Curie (Paris, France) in 2015. She joined the Institute of Condensed Matter Chemistry of Bordeaux (France) as a postdoctoral researcher for 18 months. She then joined in 2017 Drexel University (Philadelphia, USA) as a postdoctoral researcher. She belongs to the CNRS as a researcher since 2019. Her research activity is focused on non-oxide chalcogenide glasses and glass-ceramics for optical and energy storage applications. She is currently exploring mechanochemistry to obtain new ion conducting glasses for solid state electrolytes.
Using mechanochemistry to explore new sodium conducting glasses and glass-ceramics.
Sulfur-based glasses are attracting growing interest as solid-state electrolytes because of their high ionic conductivity compared to their oxide counterparts, and their mechanical properties. They are classically synthesized by the melt quenching method in silica tube. However, this process poses problems of safety, scalability, cost and limits the glass compositions available, due to the reactivity of alkali with silica. An alternative to high-temperature syntheses and solvent-based processes is the use of mechanical milling techniques. In this talk, we show how mechanochemistry can be used to extend the glass forming domain in the Na2S-Ga2S3 pseudo binary and the Na2S-Ga2S3-GeS2 pseudo ternary. The conductivity properties and structure of these new Na and Ga-rich glasses are discussed. Crystallization tests are also performed to obtain glass-ceramics in these systems, and crystalline NaGaS2 is obtained by annealing the glass above its glass transition temperature. This new NaGaS2 synthesis route offers significant advantages over the state-of-the-art: the synthesis temperature is lowered by about 50 %, it is a solvent-free route and a large quantity of material can be synthesized. Although the ionic conductivity measured for NaGaS2 is not high enough for a candidate for solid-state electrolytes, this compound holds great promise for a variety of applications due to its layered structure and ion-exchange properties.
