Studies of LaSn3 as a Negative Electrode for Lithium-Ion Batteries

The intermetallic compound LaSn3 has been explored as a possible negative electrode for lithium-ion batteries. A combination of experiment and density functional theory calculations provides evidence that the structure is intolerant to lithium insertion and that the electrochemical reaction occurs via a displacement mechanism. Experiment shows that approximately six Li react initially with LaSn3; calculated energetics suggest that during the reaction La3Sn5 and lithiated tin are formed and that the electrode operates by delithiation and relithiation of the Sn particles within an inert lanthanum-tin matrix. LaSn3 electrodes provide a reversible specific capacity of 200-250 mAh/g, whereas In-substituted electrodes that form a solid solution with LaSn3, such as LaSn2.7In0.3, yield a slightly lower capacity. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3125132] All rights reserved.