Structural Studies in Lithium Insertion into SnO-B[sub 2]O[sub 3] Glasses and Their Applications for All-Solid-State Batteries

Abstract

The local structure of electrochemically lithium-inserted glasses was investigated by several spectroscopic techniques to clarify a lithium insertion mechanism into the glasses. 50SnO⋅50 (mol %) glass showed two plateaus around 1.5 and 0.5 V (vs. on the lithium insertion process and exhibited a high capacity of 1240 mAh in the case of using a conventional liquid electrolyte. On the first plateau (1.5 V vs. metallic Sn with small domains was formed and the coordination environment at boron in the glass network was not changed. On the second plateau (0.5 V vs. the borate glass network was rearranged by a transformation from tetrahedral to trianglar boron units, which provides an additional free space compensating an increase in volume followed by a formation of Li-Sn alloy domains. Hence, the larger the fraction of tetrahedral unit is in the glasses, the higher the charge-discharge capacities are. The glasses are applicable to all-solid-state lithium rechargeable batteries as anode materials with high capacity. © 2003 The Electrochemical Society. All rights reserved.