The fabrication of thin film cathode for solid-state microbattery by sol-gel method

Abstract

LiMn2O4 thin films were prepared by a sol-gel method using spin-coating and annealing processes. Unhydrous Mn(CH3COCHCOCH3)(3)(manganese acetylacetonate) and LiCH3COCHCO-CH3(lithium acetylacetonate) were chosen as source materials, The film electrochemical proper-ties depended on the drying temperature even when subjected to the same annealing conditions. The discharge capacity of annealed film increased as the drying temperature was increased. However, the rate of capacity fading during cycling increased as the drying temperature was increased. LiCoO2 thin films are also fabricated by a sol-gel spin coating method and a post-annealing process. The thermal decomposition behavior of precursor is investigated by TG/DTA and mass spectroscopy. The crystallinity, microstructure and electrochemical properties of final films are also studied by XRD, SEM and galvanostatic charge/discharge cycling test. Films heat-treated under appropriate conditions exhibit high capacity and good crystallinity so those films are considered to be candidates as cathodes for thin-film microbatteries.