Ionic distribution and conductivity in lithium garnet Li7La3Zr2O12

The garnet-related oxide with nominal formula Li7La3Zr2O12 prepared by the sol–gel method is cubic, space group Ia-3d with lattice parameter a = 12.9720 Å at room temperature. The occupancies of three lithium positions (24d, 48g, 96h) and the position of a small amount of Al3+ (ca 0.61 wt%) inside the grains were determined by neutron diffraction. The occupancy of the 24d Li sites was reduced to 36.0% by the Al3+ occupying the 48g sites. The bulk and total Li+-ion conductivity at 25 °C was 3.1 × 10−4 S cm−1 and 1.4 × 10−4 S cm−1 with an activation energy 0.34 eV in the temperature range 25–160 °C.

► Garnet-related compound Li7La3Zr2O12 was prepared by new sol–gel method at 1200 °C.
► The bulk and total Li+-ion conductivities at 25 °C are 3.1 × 10−4 and 1.4 × 10−4 S cm−1.
► 6.02 Li+ could be located at three different lithium positions (24d, 48g, 96h).
► 0.25 Al3+ per formula unit occupy the 48g site in the framework.
► The Li+ occupancy of 24d, 48g and 96h sites is 23.3%, 24.7% and 32.0%, respectively.