A Theoretical and Experimental Study of the Lithiation of η[sup ʹ]-Cu[sub 6]Sn[sub 5] in a Lithium-Ion Battery

Abstract
The mechanism of Li insertion in η′­Cu6Sn5η′­Cu6Sn5 to form Li2CuSnLi2CuSn is discussed in detail, based on both theoretical calculations and experimental results. The mechanism is investigated by means of first principles calculations, with the full potential linearized augmented plane wave method, in combination with in situ X-ray diffraction experiments. The η′­Cu6Sn5η′­Cu6Sn5 structure, as well as its lithiated products, were optimized and the electronic charge density calculated in order to study the change in bond character on lithiation. The average insertion voltage of the η′­Cu6Sn5­Li2CuSnη′­Cu6Sn5­Li2CuSn transformation has been calculated to be 0.378 V, in good agreement with the experimental value. © 2003 The Electrochemical Society. All rights reserved.