Microwave-assisted selective preparation and characterization of Li21Si5 and Li17Sn4

摘要

Two types of intermetallic lithium alloys, Li21Si5 and Li17Sn4 (previously Li22Si5 and Li22Sn5), were prepared for the first time using microwave-assisted solid-state reaction. The optimum oven power for their preparation is 80-60%, and the irradiation times are 5 min for Li21Si5 or 10 min for Li17Sn4. A cheap alumina crucible was found to be the most suitable container in quick (less than 10 min) microwave reactions for Li-containing alloys. The synthesized compounds were characterized by PXRD. Mossbauer spectroscopy was used to characterize Li17Sn4 under different conditions. The hyperfine interaction parameters of Sn-119 in Li17Sn4 show a typical Li-Sn alloy Sn isomer shift (1.88 mm/s). The oxidization processes of the two intermetallic lithium alloys in air were investigated. The microwave method was found to be simple, fast and efficient, with high selectivity for the preparation of these compounds. (C) 2004 Elsevier Inc. All rights reserved.