Effect of annealing on properties of lithium aluminum germanium phosphate electrolyte thick films prepared by aerosol deposition

Li1.5[Al0.5Ge1.5(PO4)3] glass-ceramic powder was used for the deposition of thick films on silicon substrate by aerosol deposition. The deposited films were annealed at 873 K and 1023 K for 6 h in air. The thickness of the films was 10–12 m and the relative density was 78%–82%. As-deposited films had nano-scale grains and amorphous regions while in the annealed films, the grain growth and improved crystallinity were observed. The grain size was increased from 12 nm to 25 nm and 97 nm after annealing at 873 K and 1023 K, respectively. The ionic conductivity of the as-deposited film was 8.49 × 10−9 S cm−1, which increased to 1.06 × 10−5 S cm−1 and 1.16 × 10−4 S cm−1 after annealing at 873 K and 1023 K, respectively. The increased ionic conductivity is explained in terms of the increased grain size as well as the improved crystallinity.