Sintering analysis of garnet-type ceramic as oxide solid electrolytes for rapid Li+ migration

Metallic doping can stabilize cubic phase Li7La3Zr2O12 (LLZO) solid electrolyte for high conductivity, due to the enhanced vacancies and disordered Li-site. However, the understanding of metallic doping in the crystal lattice during the high-temperature sintering process is still not clear. In present study, a gradient series of Fe doped LLZO are formulated via solid-phase reaction, and then investigated through crystal analysis and morphological characterization. Pair distribution function essay implies that doped Fe3+ promotes random distribution of Li+ over the available sites in the located crystal. Additionally, the ceramic morphology confirms that the particles sizes in LLZO pellets suddenly grow above 1000 ℃, and Fe doping can obviously suppress Li loss above 600 ℃. As a result, the LLZF0.15 exhibits the relatively high ionic conductivity of 1.99 × 10–5 S cm–1 at 45 ℃.