LiCoO2 and LiMn2O4 thin-film electrodes for rechargeable lithium batteries - Preparation using PVP sol-gel to produce excellent electrochemical properties

LiCoO2 and LiMn2O4 thin-film electrodes for rechargeable lithium batteries were prepared by a sol-gel method with poly(vinylpyrrolidone) (PVP). The Li-Co-O and Li-Mn-O sols were successfully prepared by using PVP. The sol coated on an Au substrate by a spin coater was converted to a gel film through the spin-coating process. The gel films were heated at 800degreesC for 1 h. The prepared thin films were characterized with both the X-ray diffraction method and scanning electron microscopy. From these results, it was found that the films prepared from Li-Co-O and Li-Mn-O sols were LiCoO2 with a rock-salt-like structure and LiMn2O4 with a spinel structure, respectively. Electrochemical properties of the prepared films were evaluated with charge and discharge tests and cyclic voltammetry in a mixed solvent of ethylene carbonate and diethyl carbonate (1:1 in volume) with 1.0 mol dm(-3) LiClO4. These results showed that these thin-film electrodes have excellent electrochemical properties. (C) 2002 The Electrochemical Society.