Structure and lithium‐ion mobility in Li_1.5M_0.5Ge_1.5(PO₄)₃ (M = Ga, Sc, Y) NASICON glass‐ceramics

Abstract

This work reports structural and lithium-ion mobility studies in NASICON singleor 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. K E Y W O R D S ionic conductivity, nuclear magnetic resonance, phosphates, structure How to cite this article: d'Anciães Almeida Silva I, Nieto-Muñoz AM, Rodrigues ACM, Eckert H. 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. J Am Ceram Soc. 2020;103:4002-4012. https ://doi.

Electrical and Structural Properties of Li1.3Al0.3Ti1.7(PO4)3—Based Ceramics Prepared with the Addition of Li4SiO4

“…The two closely located signals at −14.6 and −16.3 can be assigned to the Li 1+x Al x Ti 2−x (PO 4 ) 3 phase. In such a case, their occurrence may be related to the existence of two NASICON-type phases with slightly different chemical compositions [24,42,47,48]. The last resonance at −19.6 ppm may have been due to the presence of a LiAlP 2 O 7 compound [24,41,42].…”

“…This may be related to the slightly different composition of the material when sintered at 800, 900, or 1000 °C. Based on this fact, different values were reported for grain and total activation energy [5,7,9,12,14,[17][18][19]23,24,26,[28][29][30]35,48]. The values of the apparent grain and total conductivity can be calculated by employing the equation σ = L/(R•A), where L and A represent the sample thickness and electrode area.…”

“…Considering E tot , one may notice that this value was nearly the same for LATP-LSO sintered at 800 • C and it decreased to ca. 0.39 eV when the composite was sintered at 900 • C or 1000 • C. This may be related to the slightly different composition of the material when sintered at 800, 900, or 1000 • C. Based on this fact, different values were reported for grain and total activation energy [5,7,9,12,14,[17][18][19]23,24,26,[28][29][30]35,48].…”

B2O3-Doped LATP Glass-Ceramics Studied by X-ray Diffractometry and MAS NMR Spectroscopy Methods

“…The signal at 40.5 ppm is characteristic for AlPO 4 compound in AlO 4 coordination of aluminum [30,[49][50][51][52]. The resonances located at −14.3 and −15.7 ppm correspond to aluminum in AlO 6 environment in two slightly different LATP phases [53,54,58]. The occurrence of two LATP phases was also observed by C. Vinod Chandran in Li 1+x A lx Ti 2-x (PO 4 ) 3 samples with x > 0.5 [58].…”

Understanding the Evolution of the Structure and Electrical Properties during Crystallization of Li1.5Al0.5Ge1.5(PO4)3 and Li1.5Sc0.17Al0.33Ge1.5(PO4)3 NASICON -Type Glass Ceramics

“…Data are presented in the sheared mode by projecting 2D contours for each individual site onto the F1 and F2 axes. The chemical shifts of all spectra were referenced to 85% H 3 PO 4 , Al 3+ solution 1 mol L –1 , and powdered ScPO 4 (−48.2 ppm) for 31 P, 27 Al, and 45 Sc nuclei, respectively. Signal deconvolution was made using the Gaussian model for 31 P, Czjzek model for 27 Al, , and 45 Sc were performed using the DMFIT software …”