Characteristics of rapid-thermal-annealed $LiCoO2$ cathode film for an all-solid-state thin film microbattery

We report on the fabrication of a $LiCoO2$ film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The $LiCoO2$ films were grown by rf magnetron sputtering using a synthesized $LiCoO2$ target in a $[O2/(Ar+O2)]$ ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited $LiCoO2$ film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed $LiCoO2$ film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm² μm. These results show the possibility of the RTA $LiCoO2$ film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively.