First Principles Calculations of Moessbauer Spectra of Intermetallic Anodes for Lithium-Ion Batteries

摘要

Changes in ~(119)Sn and ~(121)Sb Moessbauer spectra due to lithium insertion in tin and antimony based anode materials for lithium-ion batteries are analysed. Due to the complexity of the spectra linear augmented plane wave calculations of the electronic density were used to evaluate the electron density and the electric field gradients at the nucleus. The Sn Moessbauer spectrum of SnO + 3.5 Li was evaluated from the theoretical spectra of the Li-Sn alloys. The observed good agreement between experimental and ab initio spectra is consistent with the reversible lithium insertion mechanism based on the formation of Li-Sn alloys. The analysis of the Sb Moessbauer spectra for Li insertion into CoSb_3 is somewhat more complex but calculations of the Moessbauer parameters clearly indicate the existence of Li_3Sb at the end of the first discharge.