Formation of active species and aging mechanisms in tin-based anodic materials [Formation des espèces actives et mécanismes de vieillissement dans des matériaux anodiques à base d'étain]
Abstract
Various spectroscopic methods have been used in lithium ion batteries to study structural and electronic modifications of electrode materials in relation to their electrochemical properties. The experimental results have been analyzed by various models including semi-empirical and ab-initio calculations. Systems based on tin oxides or tin sulfides have been studied. It is shown that the choice of aging mechanisms will depend on the aimed battery applications. In thermodynamically stable systems, there are no losses of lithium during the first cycle but the capacities are limited and the reversibility depends on the preservation of the crystalline lattice. In metastable systems, there are significant losses of lithium during the first cycle but the capacities are high and the reversibility does not depend on the preservation of the crystalline lattice. Those observations open the way to searching new materials with particular attention paid to their texture and particle size.