Dresden 2017 – scientific programme
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SYLI: Symposium Interfacial Challenges in Solid-State Li Ion Batteries
SYLI 6: Defects, structure and thermodynamics
SYLI 6.5: Talk
Wednesday, March 22, 2017, 11:15–11:30, IFW A
Ab initio modeling of Li-rich transition metal oxyfluorides — •Holger Euchner1 and Axel Groß1,2 — 1Helmholtz Institute for Electrochemical Energy Storage, Helmholtzstraße 11, 89081 Ulm — 2Institute of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm
Recently, Li-rich transition metal (TM) oxyfluorides, were identified as promising electrode materials in Li-ion batteries [1,2]. Due to the evidenced robustness of the underlying framework – a disordered rock salt structure (DRS), consisting of two disordered fcc sublattices, exhibiting TM/Li and O/F disorder, respectively – this class of materials is a potential candidate for future application in Li-ion technology.
To provide insight into underlying mechanisms and potential for improvement, we have conducted a computational study of a number of LixTM1−xOyF1−y compounds. Using periodic density functional theory calculations, the impact of different TMs as well as different O/F concentrations on structural stability, (de-)lithiation behavior and Li diffusion is investigated. Apart from predicting open circuit voltage and energy density, we present an analysis of Li-diffusion pathways and corresponding barriers, which we relate to local environment and bonding characteristics of Li atoms.
[1] R. Chen et al., Adv. Energy Mater. 5, 9 (2015).
[2] S. Ren et al., Adv. Sci. 2, 10 (2015).