Electrical and Structural Properties of Li1.3Al0.3Ti1.7(PO4)3—Based Ceramics Prepared with the Addition of Li4SiO4 (original) (raw)
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XPS and ionic conductivity studies on Li 1.3 Al 0.15 Y 0.15 Ti 1.7 (PO 4 ) 3 ceramics
Ionics, 2010
Li1.3Al0.15Y0.15Ti1.7(PO4)3 compound was synthesized by solid-state reaction, and ceramics were sintered. The surfaces of the ceramics were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. Li1.3Al0.15Y0.15Ti1.7(PO4)3 samples were tested in solid galvanic cells Ag|O2+CO2|Li2CO3|Li1.3Al0.15Y0.15Ti1.7(PO4)3|LiMnO2+Mn2O3|O2|Ag. The electromotive force measurements of this cell indicated that investigated samples are practically pure Li-ion conductors. Impedance spectroscopy studies have been performed in the frequency range 10−2–3·109 Hz and temperatures from −57 °C to 334 °C. Three dispersion regions related to Li+ ionic transport in bulk, grain boundaries of the ceramics and to polarization of electrodes have been found. Total conductivity changes according to Arrhenius law in the studied temperature range, but an anomalous behavior was observed for the bulk conductivity of the ceramics.
2016
Lithium aluminium titanium phosphate (LATP) belongs to one of the most promising solid electrolytes. Besides sufficiently high electrochemical stability, its use in lithium-based all-solid-state batteries crucially depends on the ionic transport properties. While many impedance studies can be found in literature that report on overall ion conductivities, a discrimination of bulk and grain boundary electrical responses via conductivity spectroscopy has rarely been reported so far. Here, we took advantage of impedance measurements that were carried out at low temperatures to separate bulk contributions from the grain boundary responses. It turned out that bulk ion conductivity is by at least three orders of magnitude higher than ion transport across the grain boundary regions. At temperatures well below ambient long-range Li ion dynamics is governed by activation energies ranging from 0.26 to 0.29 eV depending on the sintering conditions. As an example, at temperatures as low as 173 K, the bulk ion conductivity, measured in N 2 inert gas atmosphere, is in the order of 8.1 Â 10 À6 S cm À1. Extrapolating this value to room temperature yields ca. 3.4 Â 10 À3 S cm À1 at 293 K. Interestingly, exposing the dense pellets to air atmosphere over a long period of time causes a significant decrease of bulk ion transport. This process can be reversed if the phosphate is calcined at elevated temperatures again.
Batteries, 2020
In recent years, solid lithium-ion conductors have been widely studied because of their applications as electrodes and solid electrolytes in rechargeable lithium-ion batteries. Citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) were employed to synthesize the nanostructured NASICON-type Li1.4Al0.4Ti1.6(PO4)3 ceramic. The chelating agent, together with an ethylene glycol (EG) and the esterification agent were employed to form a network decorated with uniform dispersed metal ions under specific conditions: molar ratio [complexing agent/metal ions] = 1 and the molar ratio [EG/EDTA] = 6, whereas the solution pH was kept below 1. A well crystalline NASICON structure was formed following the heat treatment of the produced gel at 630 °C. Simultaneous thermal analysis (STA) revealed lower required temperature for pyrolysis and crystallization using EDTA. Powder X-ray diffraction (PXRD) showed the formation of larger crystallite size when citric acid was employed. The data from scan...
Journal of Power Sources, 2018
Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) materials are made of a threedimensional framework of TiO 6 octahedra and PO 4 tetrahedra, which provides several positions for Li + ions. The resulting high ionic conductivity is promising to yield electrolytes for all-solid-state Li-ion batteries. In order to elaborate dense ceramics, conventional sintering methods often use high temperature ( 1000°C) with long dwelling times (several hours) to achieve high relative density ( 90%). In this work, an innovative synthesis and processing approach is proposed. A fast and easy processing technique called microwave-assisted reactive sintering is used to both synthesize and sinter LATP ceramics with suitable properties in one single step. Pure and crystalline LATP ceramics can be achieved in only 10 min at 890 °C starting from amorphous, compacted LATP's precursors powders. Despite a relative density of 88%, the ionic conductivity measured at ambient temperature (3.15 x 10-4 S.cm-1) is among the best reported so far. The study of the activation energy for Li + conduction confirms the high quality of the ceramic (purity and crystallinity) achieved by using this new approach, thus emphasizing its interest for making ion-conducting ceramics in a simple and fast way.
The interest in alternative energy sources grows rapidly and demands improved materials. The cutting-edge investigations focus attention on the development and optimization of solid electrolytes for advanced energy storage. Their chemical and structural stability defines both battery performance and lifetime, yet it is studied poorly even for well-known superionic conductors like NASICON-based compounds. In this work, we studied the Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) stability towards water. Corresponding ceramics were synthesized in pellet form through the solid-state reaction and had been immersed in deionized water for different periods of time with subsequent electrochemical (Electrochemical Impedance Spectroscopy), structural (Powder X-Ray Diffraction Analysis, Raman spectroscopy, computational modeling), chemical (ceramics-Energy-Dispersive X-ray spectroscopy; mother-solutions-Inductively Coupled Plasma Mass Spectrometry), and morphological (Scanning & Transmission Electron Microscopy) analyzes. Water exposure triggers drastic conductivity losses (64 % for σt) with accompanying lithium elution (exceeds 13 atomic %) and unit cell shrinkage. All these changes reach a plateau after 2 hours of water exposure.
Conductivity studies and ion transport mechanism in LiILi 3 PO 4 solid electrolyte
Ionics, 2009
Mixtures of LiI-Li 3 PO 4 were sintered at low temperature. It was observed that the conductivity improved up to 10 −3 S cm −1 with the addition of LiI. Infrared technique (Fourier transform infrared spectroscopy [FTIR]) was employed to detect the presence of polyhedral structures. From the FTIR spectra of the binary samples with various weight percents of LiI, the PO 4 3− bands and the PO bending experienced small shifting which indicates that interaction has occurred. Alternating current conductivity versus frequency shows a linear variation suggesting that the behavior follows Jonsher power law. The conduction mechanism of LiI-Li 3 PO 4 solid electrolyte follows the quantum mechanical tunneling model.
Journal of materials chemistry. A, Materials for energy and sustainability, 2015
Lithium aluminium titanium phosphate (LATP) belongs to one of the most promising solid electrolytes. Besides sufficiently high electrochemical stability, its use in lithium-based all-solid-state batteries crucially depends on the ionic transport properties. While many impedance studies can be found in literature that report on overall ion conductivities, a discrimination of bulk and grain boundary electrical responses via conductivity spectroscopy has rarely been reported so far. Here, we took advantage of impedance measurements that were carried out at low temperatures to separate bulk contributions from the grain boundary responses. It turned out that bulk ion conductivity is by at least three orders of magnitude higher than ion transport across the grain boundary regions. At temperatures well below ambient long-range Li ion dynamics is governed by activation energies ranging from 0.26 to 0.29 eV depending on the sintering conditions. As an example, at temperatures as low as 173 K, the bulk ion conductivity, measured in N 2 inert gas atmosphere, is in the order of 8.1 Â 10 À6 S cm À1. Extrapolating this value to room temperature yields ca. 3.4 Â 10 À3 S cm À1 at 293 K. Interestingly, exposing the dense pellets to air atmosphere over a long period of time causes a significant decrease of bulk ion transport. This process can be reversed if the phosphate is calcined at elevated temperatures again.
Solid State Ionics, 2015
With the aim to improve the ionic conductivity of perovskite materials used for all-solid-state batteries, La (2/3) − x Li 3x TiO 3 with x = 0.11 (LLTO11) ceramics was prepared by a double mechanical alloying method. The influence of thermal treatments (furnace-cooling, SC and quenching, QC) on the crystalline structure and Li-ion conductive properties of the LLTO ceramics has been studied by X-ray powder diffraction (XRD), Raman scattering and impedance spectroscopy. XRD patterns of SC-samples exhibited a doubled perovskite with a tetragonal structure, whereas those of quenched samples indicated a simple cubic perovskite. The increase in the ionic conductivity of the LLTO11 ceramics was attributed to the disordered morphology that has promoted 3D-conductive mechanism. At room temperature, the grain and grain-boundary conductivities of the quenched LLTO11 ceramics reached values as large as 1.8 × 10 −3 S•cm −1 and 7.2 × 10 −5 S•cm −1 , respectively. All-solidstate batteries made from the LLTO11 solid-state electrolyte combining with LiMn 2 O 4 , and SnO 2 thin films as cathode and anode, respectively, possessed a charge-discharge efficiency of~61% and a charging capacity of 3.0 μAh/(cm 2 • μm) at a voltage of 1.6 V.