Structural Change Studies of Cathode Materials in Lithium Batteries Relating to the Thermal Stability Using Synchrotron- Based X-Ray Techniques

摘要

Various synchrotron-based X-ray techniques have been developed and applied to investigate many important issues in Li rechargeable battery systems at BNL. The structural changes of the cathode materials under thermal abuse conditions and the interaction between cathode and electrolyte are very important in understanding the safety related characteristics. Unfortunately, most of the temperature dependent diffraction studies of the structure of the charged electrodes have been performed in the absence of electrolyte/solvents. In order to understand the mechanism of thermal degradation of the electrodes in Li-ion cells, it is very important to monitor the structural changes of the charged cathode material during heating in the presence of electrolyte. We have developed a technique using the combination of a high intensity synchrotron x-ray beam and a fast image plate detector to do time resolved x-ray diffraction during the thermal decomposition of charged cathode materials in the presence of electrolyte. In this paper, we report the results of our studies in monitoring the structural changes of the charged cathode material in the presence of electrolyte using time resolved x-ray diffraction (XRD).