A Synthesis and Crystal Chemical Study of the Fast Ion Conductor Li(7–3x)Ga(x)La(3) Zr(2)O(12) with x = 0.08 to 0.84

[Image: see text] Fast-conducting phase-pure cubic Ga-bearing Li(7)La(3)Zr(2)O(12) was obtained using solid-state synthesis methods with 0.08 to 0.52 Ga(3+) pfu in the garnet. An upper limit of 0.72 Ga(3+) pfu in garnet was obtained, but the synthesis was accompanied by small amounts of La(2)Zr(2)O(12) and LiGaO(3). The synthetic products were characterized by X-ray powder diffraction, electron microprobe and SEM analyses, ICP-OES measurements, and (71)Ga MAS NMR spectroscopy. The unit-cell parameter, a(0), of the various garnets does not vary significantly as a function of Ga(3+) content, with a value of about 12.984(4) Å. Full chemical analyses for the solid solutions were obtained giving: Li(7.08)Ga(0.06)La(2.93)Zr(2.02)O(12), Li(6.50)Ga(0.15)La(2.96)Zr(2.05)O(12), Li(6.48)Ga(0.23)La(2.93)Zr(2.04)O(12), Li(5.93)Ga(0.36)La(2.94)Zr(2.01)O(12), Li(5.38)Ga(0.53)La(2.96)Zr(1.99)O(12), Li(4.82)Ga(0.60)La(2.96)Zr(2.00)O(12), and Li(4.53)Ga(0.72)La(2.94)Zr(1.98)O(12). The NMR spectra are interpreted as indicating that Ga(3+) mainly occurs in a distorted 4-fold coordinated environment that probably corresponds to the general 96h crystallographic site of garnet.