Oxyfluorides with a disordered rock-salt structure (DRX), a new cathode material with unprecedented electrochemical properties through electronic structure arrangements that maximize both the energy storage and long-term cycling stability of the battery material. Exploration of compositions in the literature has focused on low F contents, with the highest M/F (M=3d transition metal) ratio being reached in Li2MO2F. Since these compounds are made by high-energy milling, the inherent stability of the disordered rock-salt structure at the highest F contents remains poorly understood. To address this gap, we studied the thermal stability of Li2MO2F stoichiometries with a variety of M (M= Mn, Ni, and Fe), and defined the structural transformations at different temperatures, from changes in the local structure of the oxyfluoride to decomposition into other phases, using calorimetry, X-ray diffraction and X-ray absorption spectroscopy. In this presentation, we will show how thermal treatments affect the crystal-chemistry and electrochemical performance of these F-rich phases as battery cathode materials.

Understanding crystal chemistry of newly developed disordered rock salt oxyfluorides on thermal treatment

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.