Structural Analysis by Synchrotron XRD of a Ag[sub 52]Sn[sub 48] Nanocomposite Electrode for Advanced Li-Ion Batteries

Abstract

The phase transformations of an nanocomposite anode were investigated during electrochemical lithium insertion/extraction. The high performance of the Li-ion battery gives 350 mAh/g for 300 cycles. Electrodes were prepared at selected voltage points in the discharge-charge curves, and high-energy synchrotron X-ray data was collected in order to study the reaction mechanism in detail. Structural analysis with the Rietveld method revealed a sequential Li insertion in the ternary alloy between During discharge Li is inserted into upon extrusion of Ag to form the ternary compound at 0.68 V, and as the voltage decreases the Li content increases, forming the inhomogeneous composition until the end-compound forms at 0.15 V. Moreover, below 0.2 V starts to form; and were observed. The extruded Ag forms AgLi which further forms when more Li is inserted. Finally, at full discharge, disintegrates into and © 2004 The Electrochemical Society. All rights reserved.