Fabrication of LiCoO2 thin films on flexible stainless steel substrate for lithium ion batteries

The LiCoO2 cathode coating on a flexible stainless steel has been successfully formed by using sol-gel process and spin-coating technique. The microstructures and electrochemical performance of this LiCoO2 cathode were characterized by using an X-ray diffractometer (XRD), a scanning electron microscope (SEM) and electrochemical methods. After annealing at ca. 500 degrees C, the results of XRD showed that the LiCoO2 gel was crystallized and the crystallized thin films show hexagonal phase with a space group R 3 m. When the annealing temperatures kept at 700 degrees C, the stainless steel substrate was oxidized and subsequently reacted with LiCoO2. Such a reaction also destabilized the structure of LiCoO2. The SEM observation indicated that the average grain size of films increased with increasing temperature and the thickness of spin-coated films is ca. 1-3 mu m. The LiCoO2 thin films prepared from sol-gel process and spin-coating exhibit reversible electrochemical behavior of Li+ intercalation and de-intercalation reactions. (c) 2008 Elsevier B.V. All rights reserved.