Synthesis, Crystal Structure, and Stability of Cubic Li(7–x)La(3)Zr(2–x)Bi(x)O(12)

[Image: see text] Li oxide garnets are among the most promising candidates for solid-state electrolytes in novel Li ion and Li metal based battery concepts. Cubic Li(7)La(3)Zr(2)O(12) stabilized by a partial substitution of Zr(4+) by Bi(5+) has not been the focus of research yet, despite the fact that Bi(5+) would be a cost-effective alternative to other stabilizing cations such as Nb(5+) and Ta(5+). In this study, Li(7–x)La(3)Zr(2–x)Bi(x)O(12) (x = 0.10, 0.20, ..., 1.00) was prepared by a low-temperature solid-state synthesis route. The samples have been characterized by a rich portfolio of techniques, including scanning electron microscopy, X-ray powder diffraction, neutron powder diffraction, Raman spectroscopy, and (7)Li NMR spectroscopy. Pure-phase cubic garnet samples were obtained for x ≥ 0.20. The introduction of Bi(5+) leads to an increase in the unit-cell parameters. Samples are sensitive to air, which causes the formation of LiOH and Li(2)CO(3) and the protonation of the garnet phase, leading to a further increase in the unit-cell parameters. The incorporation of Bi(5+) on the octahedral 16a site was confirmed by Raman spectroscopy. (7)Li NMR spectroscopy shows that fast Li ion dynamics are only observed for samples with high Bi(5+) contents.