Influence of sintering atmosphere on the phase,microstructure, and lithium-ion conductivity of the Al-doped Li7La3Zr2O12 solid electrolyte

Al-doped Li₇La₃Zr₂O₁₂ (Al–LLZO) solid electrolytes were sintered at 1150 ^°C for 8 h in atmosphere of oxygen, argon and air (named as Al–LLZO–O₂, Al–LLZO–Ar and Al–LLZO–Air, respectively). All the Al–LLZO samples exhibited a single cubic garnet-type structure. The sample of Al–LLZO–O₂ possessed the highest relative density (95.60%) and the largest average grain size among the three Al–LLZO samples. Furthermore, owing to its high relative density and small number of grain boundaries, Al–LLZO–O₂ demonstrated a higher lithium-ion conductivity than Al–LLZO–Ar and Al–LLZO–Air.