A study at room temperature and 55 °C on the charge-discharge characteristics of Si(100-x)Alx thin film anode for Li-ion batteries

In this study, Al was added into Si matrix as the buffer (Si90Al10, Si75Al25 and Si55Al45) by co-sputtering to prevent the dramatic volumetric expansion of a pure Si thin film anode during lithiation and delithiation. The electrochemical properties and structural characteristics of Si(100-x)Alx (at.%) films at room temperature and 55 degrees C were investigated. At 55 degrees C, the higher lithiation and delithiation quantity was accompanied by a dramatic volumetric expansion which increased the capacity but degraded the stability. In addition, the resistance against electrochemical reactions was controlled by the diffusion rate of lithium ions at 55 degrees C. After charge-discharge, the Si-Al thin film had undergone recrystallization and had been affecting the 55 degrees C charge-discharge characteristics of the thin film anodes. (C) 2012 Elsevier B.V. All rights reserved.