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Solid-state electrolytes (SSEs) are considered as the most promising materials for enabling the safer, more efficient, and feasible solution to address the market demands for lithium-ion batteries. The current work investigates the production of inorganic SSEs from silicate minerals, which are abundant materials in natural resources (kaolinite) as well as in industrial waste-streams (amorphous silica). The synthesized materials showed high amorphous contents combined with lithium silicate phases at variable proportions, according to the molar proportions of the reacting system. The materials have been characterized with XRD, SEM/EDS, FTIR, TGA-DSC, XPS, EIS, and density measurements. The results showed that hybrid structures of amorphous and crystalline silicates can form an ordered hotchpotch morphology. The best of the hybrid SSEs presented ionic conductivity values of 1.42 × 10-4 and 1.30 × 10-4 Scm-1 for samples with total amorphous contents of 73 and 83 wt%, respectively. The connected structure between amorphous and crystalline phases in a hotchpotch structure is hypothesized to assist the hopping of the Li+ ions via combined mechanisms of segmental motion of the silicates amorphous chains with defects in the crystalline phases. The proposed approach may offer new research paths towards the low-cost scalable production of SSEs.

The production of β-eucryptite [LiAlSiO4] and β-spodumene [LiAlSi2O6] from topaz [Al2SiO4(F0.64OH0.36)2, containing ~3 wt% quartz impurity] from Torrington, NSW may be of commercial importance since both lithium aluminosilicates have negative or low coefficients of thermal expansion and are used commercially as raw materials in the glass, ceramics, and metallurgical industries. A review of the literature has revealed that the production of β-eucryptite and β-spodumene from topaz has not been reported before.The aim of the present work was to determine the kinetics and reaction mechanisms of formation of β-eucryptite from topaz + lithium carbonate mixtures and β-spodumene from topaz + lithium carbonate + silica mixtures. To this end, the related reactions and subsolidus phase equilibria of the Li2O-Al2O3-SiO2 ternary system were determined.The subsolidus phase equilibria for the Li2O-Al2O3-SiO2 ternary system were investigated by literature assessment, experimentation, and thermodynamic calculations. The experimentation confirmed the previously published tentative compatibility relations in the Al2O3 and the SiO2 corners. Thermodynamic calculations were used to define the phase relations in the Li2O corner. Thermodynamic calculations also were used to define the phase equilibria for two binary subsystems, Li2SiO3-LiAlO2 and Li4SiO4-LiAlO2.The decomposition of topaz and formation of β-eucryptite from topaz + lithium carbonate mixtures and β-spodumene from topaz + lithium carbonate + silica mixtures were investigated experimentally using differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Raman microspectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM). Confirmatory thermodynamic calculations also were done.One significant finding of the present work was the formation of nanofibres from topaz + lithium carbonate mixtures at 1150°C. These fibres were fo

In order to search for new temperature compensated materials for surface acoustic wave (SAW) devices with low ultrasonic attenuation and high electromechanical coupling, the following experimental and theoretical investigations were carried out: (i) Extensive crystal growth investigations were carried out for Li2SiO3, Ba2Si2TiO8, and Pb2KNb5O15, using both Bridgman and Czochralski methods. (ii) The on-diagonal elastic constants c11, c22, c33, c44 and c55 and their temperature coefficients have been measured for Pb2KNb5O15. The temperature coefficient of c11 is positive, indicating that temperature compensated cuts should exist for this material. (iii) The theoretical equations required for the experimental determination of the complete set of piezoelectric constants from X-ray measurements have been derived. For all 20 crystal classes exhibiting the piezoelectric effect explicit expressions are given for the longitudinal and transverse piezoelectric effect, corresponding to parallel-field and perpendicular-field reflection, respectively.

This work has three major objectives: (1) to investigate a novel technique for producing beta-alumina solid electrolytes for use in sodium-sulfur cells, (2) to search for new fast ion conducting materials for protons or alkali metal ions, and (3) to examine certain mixed conductor materials for potential application in electrodes for advanced secondary battery designs., See also report dated 31 Mar 75, AD-A012 098.

Contents: Oxide fabrication via controlled oxidation of polymer precursors; The electrical response of some lithium silicates and aluminosilicates; Ramsdellite structure lithium titanate and lithium germanates; Graphite intercalation compounds; Calculation of motional activation energies for interstitial ions in the rutile structure using a minimum energy path model; Publications and presentations related to this program., See also report dated 31 Mar 74, AD-782 365.