Neutron diffraction and electrochemical studies on LiIrSn4

摘要

Large quantities of single phase, polycrystalline LiIrSn4 have been synthesised from the elements by melting in sealed tantalum tubes and subsequent annealing. LiIrSn4 crystallises with an ordered version of the PdGa5 structure: I4/mcm, a = 655.62(8), c = 1128.6(2) pm. The lithium atoms were clearly localised from a neutron powder diffraction study: R-p = 0.147 and R-F = 0.058. Time-dependent electrochemical polarisation techniques, i.e. coulometric titration, chronopotentiometry, chronoamperometry and cyclic voltammetry were used to study the kinetics of lithium ion diffusion in this stannide. The range of homogeneity (Li1+Delta deltaIrSn4, -0.091 <= delta <= + 0.012) without any structural change in the host structure and the chemical diffusion coefficient (similar to 10(-7)-10(-9) cm(2)/s) point out that LiIrSn4 is a first example of a large class of intermetallic compounds with lithium and electron mobility. Optimised materials from these ternary lithium alloys may be potential electrode material for rechargeable lithium batteries. (C) 2005 Elsevier Inc. All rights reserved.