Effects of vacuum annealing on the chargedischarge characteristics of eutectic AlSi/Al thin film as anode material for li-ion batteries

Abstract

In this study, radio frequency magnetron sputtering was used to prepare eutectic AlSi/ Al bi-layered films as anode materials and the effect of vacuum annealing in the chargedischarge capacity characteristics at different temperatures were discussed. For the purpose of 400nm AlSi film can possess the lowest crystallization temperature, the eutectic composition was adopted. The pre-sputtered 40nm Al thin film not only reduced the resistivity of the composite anode film, but also diffused to prevent peeling between the AlSi films and Cu foils after vacuum annealing. While the annealing temperatures were elevated (RT ̃ 400°C), indexes of crystalline (IOC) and resistivities of specimens were changed. The properties of materials containing ASEC-400 (at RT) and AS EC-200 (at 55°C) had outstanding chargedischarge characteristics. The morphology transformation at the surface and cross section resulted from annealing at different temperatures and cycling testing were examined by Focus Ion Beam (FIB). Besides, the relationship between cycling performances and electrochemical characteristics of AlSi/ Al film anodes were also investigated by Cyclic Voltammetry and Electrochemical AC Impedance Spectroscopy (EIS). © 2012 The Japan Institute of Metals.