| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1531018 | Materials Science and Engineering: B | 2007 | 7 Pages |
We report the synthesis, structure and transport properties of the new chemical compositions Li5La3Bi2O12 and Li6SrLa2Bi2O12. Qualitative phase analysis by X-ray powder diffraction patterns in combination with the Rietveld method revealed garnet type compounds as major phases. Whereas Li5La3Bi2O12 was found to be a single-phase material, BiLa2O4.5 could be identified as an impurity phase in the case of Li6SrLa2Bi2O12. Lithium ion conductivities of Li5La3Bi2O12 and Li6SrLa2Bi2O12 were studied by ac impedance method. The grain-boundary contribution to the total (bulk + grain-boundary) resistance is appreciable and amounts to about 54% and 61% for Li5La3Bi2O12 and Li6SrLa2Bi2O12, respectively, at 22 °C. Li6SrLa2Bi2O12 exhibits the highest total (bulk + grain-boundary) and bulk ionic conductivity of 2.0 × 10−5 and 5.2 × 10−5 S/cm, respectively, at 22 °C. The bismuth containing lithium garnet exhibits a maximum cubic lattice constant and the best lithium ion conductivity with low activation energy in the Li5La3M2O12 (M = Ta, Nb, Sb and Bi) series.
