Characterization of Li insertion mechanisms in negative electrode materials for Li-ion batteries by Moessbauer spectroscopy and first-principles calculations

摘要

The Moessbauer spectroscopy is an efficient experimental tool to study lithium insertion mechanisms in negative electrodes of Li-ion batteries at the atomic scale. However, a quantitative interpretation of the experimental data is often difficult due to the complexity of the spectra and we propose to use first-principle calculations of the hyperfine parameters. Three different types of negative electrode materials are considered. First, the experimental ~(119)Sn Mossbauer spectrum obtained for the insertion of 3.5 Li into SnO is compared to the theoretical spectrum, which clearly establishes the existence of Li-Sn stable phases. Then, the analysis of the ~(121)Sb Moessbauer spectra for metal antimonides at the end of the first discharge shows different behaviours depending on the lithium rate. Finally, tin and iron doped titanates are considered to study changes in Ti local environments during lithium insertion.