Structural analysis of pure and electrochemically lithiated SiO using neutron elastic scattering

Neutron elastic scattering was used to determine the structure of as-received and lithiated amorphous SiO which has been proposed as an anode material for lithium ion secondary batteries. Based on a comparison between the total radial distribution functions [RDF(r)] of SiO and SiO2, it was suggested that amorphous SiO is composed of a three-dimensional SiO4 tetrahedral network similar to silica (SiO2) glass and metallic silicon clusters, and that the latter were finely dispersed in the SiO4 matrix. On the other hand, electrochemically lithiated SiO showed a typical lithium negative correlation together with the disappearance of the Si-Si correlation in the RDF(r) which indicated that lithium predominantly reacted with the metallic silicon to form Li-Si alloys. (C) 2004 The Electrochemical Society.