Lithium isotope tracing in silicon-based electrodes using solid-state MAS NMR: a powerful comprehensive tool for the characterization of lithium batteries
Manon Berthault, A. L. Buzlukov, Lionel Dubois, Ariane Bayle, Willy Porcher, Thibaut Gutel, Éric De Vito, Michel Bardet
Abstract
Li ratio of any similar samples. This method was applied to study the phenomena occurring at the interface between a silicon electrode and a labeled electrolyte, which is an essential step for isotopic tracing experiments in systems after the formation of the solid electrolyte interphase (SEI). Beyond the isotopic exchanges between the SEI and the electrolyte already observed in the literature, our results show that isotopic exchanges also involve Li-Si alloys in the electrode bulk. Within a 52-hour contact, the electrolyte labeling disappeared: isotopic concentrations of the electrolyte and electrode become practically homogenized. However, at the electrode level, different silicides are characterized by rather different isotopic enrichment. In the present work, ToF SIMS and liquid state NMR were also used to cross-check and discuss the solid-state NMR method we have proposed.