Papers by Keyword: Solid Electrolyte

Abstract: The lithium aluminium titanium tantalum phosphates compounds Li₁₊xAl_xT_2-x-yTa_y(PO₄)₃ (LATTaP) with different compositions (x = 0.3; 0.02 ≤ y ≤ 0.05) were synthesized using a solid-state synthesis approach. The synthesized samples were characterized through various methods. TGA/DTG results indicate the thermal stability and complete breakdown of the stoichiometric compositions. This ensures LATTaP solid electrolytes remain stable under battery cycling, high-temperature environments, and battery applications. This was corroborated by the FTIR findings, which showed the total decomposition of volatile substances, including water molecules, CO₂, and HN₃; the wave bands associated with hydroxyl or carboxylic compounds were completely absent, with only the bands corresponding to the vibration of the PO₄ ionic group detected. This identifies chemical bonding, confirming the stability of the phosphate framework which determines structural integrity for long-term battery cycling without material degradation. The samples were successfully produced with an R-3c space group for structural characterization, assuming a hexagonal crystal structure, as referenced in the ICSD database 98-006-9677. XRD analysis demonstrated the presence of a single-phase NASICON-type crystal structure, which is essential for high ionic conductivity. The findings showed that the thermal properties of the materials are important to identify proper applicability of the material as a solid electrolyte.

Abstract: Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ (L2MO) material coated with Li_1.3Al_0.3Ti_1.7(PO₄)₃(LATP) was synthesized by sol-gel method. The coating amount was 0%, 0.5%, 1%, 1.5%, 2%. It is found that LATP coating improves the cycle stability of the material. After 200 cycles at 0.6 C rate, the cycle retention rate of the uncoated sample is 72.7%, while the retention rate of sample with 1% coating amount reaches 85%. LATP coating improves the rate performance of the material. The sample with 1% coating amount has the best rate performance, and the discharge specific capacity is 71.5 mAh/g at 10 C rate, while the discharge specific capacity of the sample without coating is 60.1 mAh/g. LATP coating alleviates the side reaction between the material surface and the electrolyte. As a solid electrolyte, it promotes the transmission of Li⁺ and reduces the charge transfer impedance of the material. The thermal stability of these materials was tested by DSC. The results show that LATP coating could improve the thermal stability of the material in charged state.

Abstract: In this paper, we report the properties of Sm and Zr co-doped CeO₂ ceramic, which synthesized by conventional solid state reaction. Sm content in Ce site was fixed at 20 mol%, meanwhile Zr was varied in the range of 5 to 15 mol%. All samples was pressed under 26 MPa before sintered at 1400 °C for 5 hours. The X-ray diffraction patterns of samples confirm all the samples are in single-phase with cubic fluorite structure. The lattice parameter decreases with increase in Zr concentration. The relative density of all samples was more that 95%. The microhardness achieved highest value for sample with 0.05 mol% of Zr. The shrinkage and the change of bulk density shows direct correlation.

Abstract: All-solid-state battery is a promising next-generation energy storage and conversion device and the development of solid electrolyte is very important as the core of all solid-state batteries. Herein lithium-indium chloride solid electrolyte is successfully prepared and the ionic conductivity is increased from 1.07 to 1.41 mS/cm by optimizing the vacuum parameter in the process of preparation. The samples have typical C2/m space group of cubic crystal system, and the vacuum optimized sample has more regular ion arrangement, better crystallinity and fewer lattice defects. The prepared sample is used as the electrolyte layer and the electrolyte part of the composite cathode, and the layered oxide LiNi_0.6Co_0.2Mn_0.2O₂ without surface modification was used as the active material. After assembling the cell, the initial discharge specific capacity of the cell was tested to be 157.5mAh/g. In addition, the phase transition of the composite cathode is analyzed under different charge and discharge state. It is found that the use of the lithium-indium chloride solid electrolyte in composite electrode does not affect the REDOX reaction of LiNi_0.6Co_0.2Mn_0.2O₂ layered oxide, indicating that the electrolyte material is stable and compatible with layered cathode material, showing its excellent application prospect.

Abstract: LiFePO₄ (LFPO)-based composite cathode was deposited on Li_0.35La_0.55TiO₃ (LLTO) solid electrolyte via slurry coating method. A composite cathode comprising of LiFePO₄, LLTO, and carbon black (CB) were mixed together in a slurry and deposited on a dense LLTO pellet substrate. The effects of heat treatment temperature and hot-pressing in the structure and densification of the deposited composite cathode were investigated. Cathode component precursors were analyzed for its particle size distribution using particle size analyzer and revealed a bimodal particle size distribution for each component materials. Structural characterization using X-ray powder diffraction (XRD) analysis revealed that distinct XRD peaks were observed which can be attributed to LFPO and LLTO for the deposited as-dried and heat treated (450 °C ) composite cathodes. Surface and cross-sectional SEM images revealed that hot-pressing provided denser morphology with smaller thickness as compared to the just as-dried and heat treated samples without the application of temperature with pressure.

Abstract: In this study, bulk lithium-ion conducting solid electrolyte of Ga-doped Li₇La₃Zr₂O₁₂ (Li_7-3XGa_xLa₃Zr₂O₁₂) where x = 0.1 (Ga-LLZO) was prepared via hot pressing at 500 °C. Precursor powder for hot-pressing was prepared using conventional solid state reaction method. Planetary ball milling was employed to investigate the particle size effect on the structure and densification of hot-pressed samples. XRD patterns of the bulk hot-pressed sample revealed a crystalline phase of which the major peaks observed can be indexed to a cubic LLZO structure; however, a major impurity phase of La₂Zr₂O₇ was observed for the ball-milled sample. Thermogravimetric and differential thermal analysis showed about 12% weight loss below 900 °C which may have affected the observed hot-pressing structure. Although lower density measurement and an impurity phase of La₂Zr₂O₇ were observed for the ball-milled sample, ball-milling also resulted to a more homogeneous and finer particle size as shown by SEM images results.

Abstract: Lithium Lanthanum Titanate, Li_3xLa_(2/3)-x□_(1/3)-2xTiO₃, with three different compositions of (i) x = 0.097 (Li_0.29La_0.57TiO₃), (ii) x = 0.117 (Li_0.35La_0.55TiO₃), and (iii) x = 0.167 (Li_0.50La_0.50TiO₃) were prepared via solid state reaction synthesis sintered at 1150 °C for 36 hours. X-ray diffraction (XRD) analysis revealed that all samples can be indexed to a cubic perovskite structure with lattice parameter a of about 3.86 Å. Morphological analysis using SEM showed that the samples are relatively dense and the calculated relative density of the LLTO samples range from about 94% to as high as 99% with increasing trend as Li content increases. Room temperature conductivity and its temperature dependence up to 120 °C were investigated. LLTO sample with x =0.117 revealed the highest total ionic conductivity at room temperature of about 1.69 x 10^-03 S/cm which can be a promising solid electrolyte for an all-solid-state lithium-ion batteries.

Abstract: The material with NASICON-type structure, lithium aluminum titanium phosphate with vanadium substituting phosphorous (Li_1.4Ti_1.6Al_0.4(PO₄)_2.9(VO₄)_0.1) (LATPV) has been synthesized via solid state method. The X-ray powder diffraction analysis shows the effect of vanadium in the composition LATPV. Various secondary phases have been observed due to vanadium substitution which leads to low ionic conductivity of σ = 2.5 x 10^-5 (Ωm)^-1. The thermal analysis indicated that the reaction of chemical mixture become stable at round 460 °C which indicated an improvement in the material densification.

Abstract: Solid electrolytes such as lithium lanthanum zirconate have shown a lot of promise in an all-solid-state Lithium-based battery since the discovery of its highly conductive cubic garnet structure. In this study, different concentrations of Al-doped Lithium Lanthanum Zirconate (Al-doped LLZ) having the formula of Li_7-.3xAl_xLa₃Zr₂O₁₂ with x = 0.1,0 .2, 0.3, were synthesized via modified Pechini method and the effect of sintering temperatures, 1150 and 1200 °C, on the resulting properties were investigated. X-ray diffraction results have shown that cubic Al-doped LLZ can be obtained at a lower temperature using Pechini method. Significant effect to the conductivity on the different sintering temperatures was observed for the 0.1 Al-doped LLZ. With the different studied compositions synthesized via modified Pechini method, it was revealed that the 0.2 Al doped LLZ sintered either at 1150 or 1200 °C showed the highest conductivity of about 1.4x10^-4 S/cm.

Abstract: YSZ film was fabricated by a facile electrophoretic deposition process using commercial YSZ powders. YSZ films with average thickness of around 10 µm were deposited on LSM/YSZ substrate at 20 V for 20 minutes and subsequently sintered at 1200 °C, 1300 °C, and 1350°C. XRD patterns of the deposited and sintered films can be attributed to mostly cubic YSZ phase. On the other hand, SEM images revealed that a sintering temperature above 1300 °C was needed to obtain a denser YSZ film. The film morphology also showed that as the sintering temperature increases, the YSZ grain size also increases.