Low temperature cubic garnet-type CO2-doped Li7La3Zr2O12

Low temperature cubic garnet-type Li7La3Zr2O12 was obtained by annealing the tetragonal Li7La3Zr2O12 at 450 °C for 20 h in air. The cubic phase was not observed by annealing at 450 °C in oxygen and argon atmospheres. The phase transition of the tetragonal to cubic phase was reversible in air and could be explained by CO2 absorption of around 2.5 wt.%. The low temperature cubic Li7La3Zr2O12 had a low bulk ionic conductivity of 1.3 × 10− 6 S cm− 1 at 25 °C, which is lower than those of the tetragonal Li7La3Zr2O12 (3.3 × 10− 6 S cm− 1) and high temperature cubic phases (5.8 × 10− 4 S cm− 1).

► Low temperature cubic phase of Li7La3Zr2O12 (LLZ) was obtained by annealing tetragonal LLZ.
► The low temperature cubic LLZ was transferred to the tetragonal phase at annealing at 800 °C for 1 h.
► The low temperature cubic LLZ contained about 2.5 wt.% CO2.