Structure and lithium‐ion mobility in Li 1.5 M 0.5 Ge 1.5 (PO 4 ) 3 (M = Ga, Sc, Y) NASICON glass‐ceramics

This work reports structural and lithium‐ion mobility studies in NASICON single‐ or multiple phase Li 1+ x M x Ge 2− x (PO 4 ) 3 (M = Ga 3+ , Sc 3+ , Y 3+ ) glass‐ceramics using solid‐state NMR techniques, X‐ray powder diffraction, and impedance spectroscopy. X‐ray powder diffraction data show the successful incorporation of Ga 3+ and Sc 3+ into the Ge 4+ octahedral sites of the NASICON structure at the levels of x  = 0.5 and 0.4, respectively. The glass‐to‐crystal transition was further characterized by multinuclear NMR and electrical conductivity measurements. Among the studied samples, the gallium‐containing glass‐ceramic presented the highest DC conductivity, 1.1 × 10 −4  S/cm at room temperature, whereas for the Sc‐containing samples, the maximum room temperature conductivity that could be reached was 4.8 × 10 −6  S/cm. No indications of any substitution of Ge 4+ by Y 3+ could be found.