Papers by Keyword: Solid Electrolyte

Abstract: This experiment composes irreversible cells using ultrafine electrolyte materials and platinum slices, to measure the ionic conductivity the cells at normal temperatures with the help of impedance 1286 spectroscopy. We have calculated the ionic conductivities, which indicate that the ionic conductivities of the merchant LaF3 polycrystalline powder and the powder by microwave method are higher than the ones of LaF3 crystal and the powder by Sol-Gel method, to achieve 10-6 Scm-1, so, they are better ionic conductors at normal temperature and can be used as sensor base materials. The experimental data show that O- participates in ionic conduction.

Abstract: In a previous study, we have proposed a model that describes the non-Arrhenius ionic conduction behavior in superionic glasses. In the present report, the model is applied to analyze the conductivity behavior of a wide variety of solid electrolytes that include crystals, glasses, polymers, composites and mixed ionic-electronic conductors. From the analysis of the model, the physical factor responsible for the non-Arrhenius behavior has been extracted and discussed.

Abstract: The compositions La0.56Li0.33TiO2.95F0.05•xLiF (x=0-025) were prepared by addition of LiF to the disordered form of the well-known Li ion conductor La0.56Li0.33TiO3. Although the total conductivities improved, there was no change in the bulk conductivity with LiF addition. No reflections due to LiF were observed in their XRD patterns, and the profiles and the chemical shifts of their 19F MAS-NMR resonances were almost the same as those of LiF. The results indicate that no substitution of F takes place, and that the added LiF acts simply as a sintering assistant agent.

Abstract: The lithium ion conducting properties of lithium- and MⅣ (M = Al, In, Y)-doped zirconium pyrophosphates synthesized via solid state reaction were investigated. The ionic conductivity of the compounds increased with increasing Li content. The activation energy of LixMxZr1-xP2O7 decreased as the lattice parameter increased owing to the enlargement of the size of bottleneck between the cavities. Li0.55(Li0.15Y0.1Zr0.75)P2O7 with a high Li content and a large lattice parameter exhibited a conductivity of 1.7×10-3 S cm-1 at 350 °C, which is sufficient for its application as a solid electrolyte for sensors.

Abstract: Na- β"-alumina solid electrolyte proposed for electric vehicle battery system application was prepared using liquid phase sintering method. Firstly, the Na- β"-alumina powder was prepared according to the formular Na1-xMg2xAl5-xO8 with x = 0.175, calcinations temperature was at 1200 C for 10 h. Calcined powder was milled and mixed with Bi2O3 or CuO in approximate concentration 1, 3 and 5 percent by mole respectively. The uniaxial dry-pressing was employed for green body forming. The green pellets were then sintered at different temperature and dwell time were kept constant for 4 h during the sintering process. Ionic conductivity measurement was performed by impedance analyzer. The XRD characterization on both powder and ceramic show that β"-alumina form as a major phase with tiny amount of the secondary phase β-alumina. The β"/β concentration proportion slightly decrease after sintering. Addition with Bi2O3 or CuO do not lead to phase change and high densification ceramic is obtained. Ionic conductivity of β"-alumina ceramic added with Bi2O3 is higher than that of ceramic with CuO addition. The relative calculated activation energy of the Na+ migration in the former composition is also lower. The highest ionic conductivity measured at 300 C is found in ceramic sample sintered at 1450 C and with 1 mol% of Bi2O3.

Abstract: Na--alumina with MgO stabilized was produced through solid state reaction. High purity starting material, -Al2O3, -Al2O3, Na2CO3 and MgO were used. The desired amount of starting materials corresponding to the nominal formula Na(1+x)MgxAl(11-x)O17 were mixed and calcined at temperature 1200 for 10 h under atmospheric pressure. The effect of Al2O3 source on phase formation and averaged crystallite size of Na--alumina were investigated via X-ray diffraction (XRD), SEM and TGA/DTA. The XRD result show that formation of Na--alumina with high purity is obtained when -Al2O3 was used. The larger crystallite size is found for sample prepared form -Al2O3. For SEM study the Na--alumina microstructure is seen as randomly packing of several sheets. Calculated crystallite size of sample prepared from -Al2O3 show the larger value compared to that one prepared from -Al2O3.

Abstract: Electrophoretic deposition method was applied to prepare some solid-electrolyte thick-films of Na1+xZr2SixP3-xO12 (x = 2, 3; NASICON) and Na5DySi4O12 (NDSO) on Au-coated alumina substrates. With the ethanol-based medium, the deposition process was investigated under constant voltage mode. The concentration of the suspension and applied voltage were optimized with respect to the rate of deposition and quality of the deposit. The NASICON (Na3Zr2Si2PO12) -based solid-state ionic conductor thick-film as a host ceramic with a guest Cu+ ion has been produced as a noble phosphor thick-film by using an electrochemical ion doping method. The photoluminescence (PL) device of the NASICON:Cu+ film showed good photo-luminescent peaks near 450-500nm depending on the host materials.

Abstract: The ternary oxide compositions xZrO2-(0.5–x/2)Al2O3-yP2O5(x=0.8, 0.9, 0.95, 1.0; y=1.0, 1.2, 1.4) and 0.9ZrO2-0.05In2O3-1.4P2O5, xSiO2-(0.5–x/2)Al2O3-1.4P2O5(x=0.9, 1.0) were synthesized by sol-gel methods, and their conductivities were investigated by ac-impedance spectroscopy. The conductivity increased with increasing P2O5 content and with decreasing heat-treatment temperature. The maximum conductivities reached over 10-2 Scm-1 at 150°C for 0.9ZrO2-0.05Al2O3-1.4P2O5 and at 225°C for 0.9SiO2-0.05Al2O3-1.4P2O5.

Abstract: Amorphous fine powder in the Li2O-Al2O3-TiO2-P2O5 (LATP) system were prepared directly from a mixture of Li2O, Al2O3, TiO2, and P2O5 as starting materials using a mechanical milling technique at room temperature. LATP glass-ceramics were obtained by heat treatment of the mechanochemically prepared amorphous powder over the crystallization temperature. X-ray diffraction peaks due to LiTi2(PO4)3 and AlPO4 crystals for LATP glass-ceramics were observed. Thus, high lithium ion conducting LATP glass-ceramics solid electrolytes were prepared successfully from the mechanochemically prepared amorphous powder. The LATP glass-ceramic fine particles were investigated as coating materials of LiCoO2 cathode in lithium ion batteries. The LATP glass-ceramics coated LiCoO2 electrode materials exhibited a good charge-discharge performance for charging up to a high voltage (4.5 V vs. Li/Li+).

Abstract: Shell-core type TiP2O7-based electrolytes were synthesized by a low-temperature sol-gel method, and their conductivities were investigated by ac-impedance spectroscopy. The samples heat-treated at 500°C showed higher proton conductivities of 3.8 × 10-2 - 1 × 10-2 Scm-1 at intermediate temperatures (100 - 300°C). The conductivity decreased by reheat-treatments at 600°C and 700°C due to a decrease in the amount of the conductive amorphous shells. However, the mechanical strength of the sample pellet significantly increased by the reheat-treatment. The sample reheat-treated at 600°C kept high conductivities of 8.8 × 10-3 - 1 × 10-3 Scm-1 in a range of 100°C - 300°C.