Electrochemical investigations of Li2AuSn2

Abstract

This paper deals with the electrochemical characterization of the lithium ternary intermetallic compound Li 2 + x AuSn 2 as an anode material for lithium cells. Li 2 + x AuSn 2 crystallizes in a tetragonal structure type with a three-dimensional [AuSn 2 ] network forming distorted hexagonal channels which are occupied by lithium atoms. GITT and PITT techniques were employed to study the kinetics of lithium ion diffusion in this ternary stannide. The chemical diffusion coefficient of lithium, D Li , was determined as a function of the lithium non-stoichiometry x with respect to the formula Li 2 + x AuSn 2 having a maximum value D Li-max = 1.5 × 10 − 6 cm 2 s − 1 at the lowest lithium content of x = 0 at 25 °C. Accordingly, Li 2 AuSn 2 is an interesting ternary intermetallic compound with good lithium and electron mobility, low potentials vs. metallic lithium and, thus, favourable as a model compound for anode materials in lithium batteries.