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

Abstract

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.