scholarly journals Influence of Lithium Content on the Structure and Ionic Conductivity of Perovskite \(\mbox{La}_{(2/3) - x}\mbox{Li}_{3x}\mbox{TiO}_{3}\) Made by Double Mechanical Alloying Method

2014 ◽  
Vol 24 (3S1) ◽  
pp. 33-39
Author(s):  
Le Dinh Trong
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Grain Boundary ◽  
Mechanical Alloying ◽  
Room Temperature ◽  
Lithium Content ◽  
Boundary Conductivity ◽  
Structural Modifications ◽  
Li Ion ◽  
Conductive Properties

Perovskite La\(_{(2/3) - x}\)Li\(_{3x}\)TiO\(_{3}\) samples with 0.06 \( \leq x \leq 0.15\) were prepared by a double mechanical alloying method. Structure and Li$^{ + }$-ion conductive properties of the La\(_{(2 / 3) - x}\)Li\(_{3x}\)TiO\(_{3}\) samples were investigated. Most of the analyzed perovskite samples exhibit a double unit cell. In these samples, a change of symmetry from tetragonal to orthorhombic is observed for sample with lithium content x = 0.06. Structural modifications were obtained mainly due to the cation vacancies ordering along the c-axis, which disappeared gradually when the lithium content increased. At room temperature, the maximum values of grains and grain boundaries conductivities of the La\(_{(2 / 3) - x}\)Li\(_{3x}\)TiO\(_{3}\) samples were found to be of \(1.5\times 10$^{ - 3}\) S/cm and \(5.8 \times 10^{ - 5}\) S/cm, respectively. The temperature dependence of ionic conductivity obeyed a non-Arrhenius behaviour. At temperature from 30 to 125\(^{\circ}\)C, the activation energy for grain and grain-boundary conductivity was found to be of $\sim $ 0.23 eV and $\sim $ 0.32 eV, respectively.

scholarly journals Effect of Annealing Temperature on the Li\(^{ + }\) Ionic Conductivity of La\(_{0.67 - x}\)Li\(_{3x}\)TiO\(_{3 }\)

2009 ◽  
Vol 19 (4) ◽  
pp. 235-242
Author(s):  
Le Dinh Trong ◽  
Pham Duy Long ◽  
Nguyen Nang Dinh
Keyword(s):  
High Temperature ◽  
Ionic Conductivity ◽  
Thermal Treatment ◽  
Grain Boundary ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Boundary Conductivity ◽  
Impedance Measurements ◽  
Post Annealing ◽  
Reactive Milling

Perovskite La0.67-xLi3xTiO3 with x = 0.10, 0.11, 0.12 and 0.13 were firstly annealed at 800 oC then treated by reactive milling, followed by post-annealing at temperatures from 1100 to 1200oC. The crystalline structure of grain and grain-boundary were characterized by XRD and SEM. The impedance measurements showed that nanocrystalline La0.67-xLi3xTiO3 after being annealed at 1150 oC possessed a grain conductivity as high as 1.3×10-3 S.cm-1. The grain-boundary conductivity was enhanced one order in magnitude after annealing at temperature higher 1100oC and consists of 5.8×10-5 S.cm-1. The results have also showed the limitation of the adiabatic thermal treatment for the improvement of the grain-boundary conductivity and suggested the way to overcome the limitation by rapidly cooling the samples from the high temperature to room temperature.

scholarly journals Effect of Reduced Atmosphere Sintering on Blocking Grain Boundaries in Rare-Earth Doped Ceria

Inorganics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 63
Author(s):  
Soumitra Sulekar ◽  
Mehrad Mehr ◽  
Ji Hyun Kim ◽  
Juan Claudio Nino
Keyword(s):  
Activation Energy ◽  
Rare Earth ◽  
Ionic Conductivity ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Complex Impedance ◽  
Doped Ceria ◽  
Composite Electrodes ◽  
Boundary Conductivity ◽  
Rare Earth Doped

Rare-earth doped ceria materials are amongst the top choices for use in electrolytes and composite electrodes in intermediate temperature solid oxide fuel cells. Trivalent acceptor dopants such as gadolinium, which mediate the ionic conductivity in ceria by creating oxygen vacancies, have a tendency to segregate at grain boundaries and triple points. This leads to formation of ionically resistive blocking grain boundaries and necessitates high operating temperatures to overcome this barrier. In an effort to improve the grain boundary conductivity, we studied the effect of a modified sintering cycle, where 10 mol% gadolinia doped ceria was sintered under a reducing atmosphere and subsequently reoxidized. A detailed analysis of the complex impedance, conductivity, and activation energy values was performed. The analysis shows that for samples processed thus, the ionic conductivity improves when compared with conventionally processed samples sintered in air. Equivalent circuit fitting shows that this improvement in conductivity is mainly due to a drop in the grain boundary resistance. Based on comparison of activation energy values for the conventionally processed vs. reduced-reoxidized samples, this drop can be attributed to a diminished blocking effect of defect-associates at the grain boundaries

scholarly journals Contribution Succinonitrile additive for Performa LiTFSi Solid Polymer Electrolytes for Li-Ion Battery

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Qolby Sabrina ◽  
Titik Lestariningsih ◽  
Christin Rina Ratri ◽  
Achmad Subhan
Keyword(s):  
Ionic Conductivity ◽  
Polymer Electrolytes ◽  
Room Temperature ◽  
Lithium Salt ◽  
Ionic Conduction ◽  
Lithium Ion ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
Half Cell ◽  
Li Ion

Solid polymer electrolyte (SPE) appropriate to solve packaging leakage and expansion volume in lithium-ion battery systems. Evaluation of electrochemical performance of SPE consisted of mixture lithium salt, solid plasticizer, and polymer precursor with different ratio. Impedance spectroscopy was used to investigate ionic conduction and dielectric response lithium bis(trifluoromethane)sulfony imide (LiTFSI) salt, and additive succinonitrile (SCN) plasticizer. The result showing enhanced high ionic conductivity. In half-cell configurations, wide electrochemical stability window of the SPE has been tested. Have stability window at room temperature, indicating great potential of SPE for application in lithium ion batteries. Additive SCN contribute to forming pores that make it easier for the li ion to move from the anode to the cathode and vice versa for better perform SPE. Pore of SPE has been charaterization with FE-SEM. Additive 5% w.t SCN shows the best ionic conductivity with 4.2 volt wide stability window and pretty much invisible pores.

Preparation of Cu-Cr-Zr/AlN Nanocomposites and their Mechanical and Conductive Properties

2011 ◽  
Vol 239-242 ◽  
pp. 2756-2759
Author(s):  
Yong Qiang Qin ◽  
Yu Cheng Wu ◽  
Yan Wang ◽  
Yu Hong ◽  
Jing Quan Deng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Room Temperature ◽  
Copper Alloys ◽  
Morphology Characterization ◽  
Conductive Properties ◽  
Conductivity Behavior

Copper and copper alloys had various applications in tremendous areas due to their unique properties, such as good conductivity, good thermal conductivity and so on. However, applications of copper and copper alloys were severely restricted as the result of the limited strength at room temperature and poor wear-resistance at high temperature. In this paper, we investigated the preparation of Cu-Cr-Zr/AlN nanocomposites by mechanical alloying process and then powder metallurgy technology. XRD and SEM were performed for the phase and morphology characterization. The conductivity properties were also tested and the results showed that Cu-Cr-Zr/AlN nanocomposites exhibited excellent conductivity behavior.

Materials for All-Solid-State Lithium Ion Batteries

2013 ◽  
Vol 1496 ◽  
Author(s):  
Sumaletha Narayanan ◽  
Lina Truong ◽  
Venkataraman Thangadurai
Keyword(s):  
Ionic Conductivity ◽  
Chemical Stability ◽  
Room Temperature ◽  
Lithium Ion ◽  
Ion Conductivity ◽  
High Ionic Conductivity ◽  
Li Ion Batteries ◽  
Li Battery ◽  
Li Ion ◽  
Very High

ABSTRACTGarnet-type electrolytes are currently receiving much attention for applications in Li-ion batteries, as they possess high ionic conductivity and chemical stability. Doping the garnet structure has proved to be a good way to improve the Li ion conductivity and stability. The present study includes effects of Y- doping in Li5La3Nb2O12 on Li ion conductivity and stability of “Li5+2xLa3Nb2-xYxO12” (0.05 ≤ x ≤ 0.75) under various environments, as well as chemical stability studies of Li5+xBaxLa3-xM2O12 (M = Nb, Ta) in water. “Li6.5La3Nb1.25Y0.75O12” showed a very high ionic conductivity of 2.7 х 10−4 Scm−1 at 25 °C, which is comparable to the highest value reported for garnet-type compounds, e.g., Li7La3Zr2O12. The selected members show very good stability against high temperatures, water, Li battery cathode Li2CoMn3O8 and carbon. The Li5+xBaxLa3-xNb2O12 garnets have shown to readily undergo an ion-exchange (proton) reaction under water treatment at room temperature; however, the Ta-based garnet appears to exhibit considerably higher stability under the same conditions.

scholarly journals Blend Hybrid Solid Electrolytes Based on LiTFSI Doped Silica-Polyethylene Oxide for Lithium-Ion Batteries

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 109 ◽  
Author(s):  
Jadra Mosa ◽  
Jonh Fredy Vélez ◽  
Mario Aparicio
Keyword(s):  
Ionic Conductivity ◽  
Solid Electrolytes ◽  
Room Temperature ◽  
Sol Gel ◽  
Lithium Ion ◽  
Hybrid Structure ◽  
Hybrid Network ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Sol Gel Synthesis

Organic/inorganic hybrid membranes that are based on GTT (GPTMS-TMES-TPTE) system while using 3-Glycidoxypropyl-trimethoxysilane (GPTMS), Trimethyletoxisilane (TMES), and Trimethylolpropane triglycidyl ether (TPTE) as precursors have been obtained while using a combination of organic polymerization and sol-gel synthesis to be used as electrolytes in Li-ion batteries. Self-supported materials and thin-films solid hybrid electrolytes that were doped with Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were prepared. The hybrid network is based on highly cross-linked structures with high ionic conductivity. The dependency of the crosslinked hybrid structure and polymerization grade on ionic conductivity is studied. Ionic conductivity depends on triepoxy precursor (TPTE) and the accessibility of Li ions in the organic network, reaching a maximum ionic conductivity of 1.3 × 10−4 and 1.4 × 10−3 S cm−1 at room temperature and 60 °C, respectively. A wide electrochemical stability window in the range of 1.5–5 V facilitates its use as solid electrolytes in next-generation of Li-ion batteries.

Optimization of polymer electrolytes with the effect of concentration of additives in PEO-NH4HF2 polymer electrolytes

2020 ◽  
pp. 089270572093075
Author(s):  
Jitender Paul Sharma ◽  
Neelam Guleria
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Ionic Conductivity ◽  
Polymer Electrolyte ◽  
Polymer Electrolytes ◽  
Fumed Silica ◽  
Room Temperature ◽  
Testing Machine ◽  
Scanning Calorimetry ◽  
Nanocomposite Polymer

In the present work, nanocomposite polymer electrolyte films were prepared by solution casting technique using nanosized fumed silica to polyethylene oxide (PEO)-based polymer electrolytes containing ammonium bifluoride (NH4HF2). The ionic conductivity of 1.19 × 10−5 S cm−1 has been observed at room temperature (25°C) for 3 wt% fumed silica in PEO-10 wt% NH4HF2 polymer electrolytes after which the conductivity was observed to decrease. Furthermore, the addition of high dielectric constant plasticizer propylene carbonate (PC) in the optimized composition of nanocomposite polymer electrolytes has increased the number of charge carriers by the large dissolution of ionic salt, amorphous content, and hence the ionic conductivity. Maximum ionic conductivity obtained at room temperature was found to be 1.55 × 10−4 S cm−1 in the case of PEO-10 wt% NH4HF2-3 wt% fumed silica-0.3 (ml) PC polymer electrolytes which is five orders of magnitude higher than that of the polymer host material. Temperature-dependent ionic conductivity, activation energy, and dielectric constant studies have been described for all the compositions of polymer electrolytes. Ionic conductivity and dielectric constant studies were determined from impedance data. Polymer electrolytes containing both fumed silica and PC highlight that there is no phase transition in the polymer electrolyte and temperature dependence of ionic conductivity in the temperature range is of almost Arrhenius type. The lowest activation energy value for the highest conducting polymer electrolyte was found to be 0.172 eV. Change in melting temperature, % crystallinity ( χ c), and mechanical properties have also been observed in polymer electrolytes containing fumed silica as well as PC as studied by Differential Scanning Calorimetry/Thermogravimetric Analysis (DSC/TGA) and universal testing machine, respectively.

Effect of Doping Concentration on Grain Boundary Conductivity of Samaria Doped Ceria Composites

2021 ◽  
Author(s):  
Prerna Vinchhi ◽  
Roma Patel ◽  
Indrajit Mukhopadhyay ◽  
Abhijit Ray ◽  
Ranjan Pati
Keyword(s):  
Ionic Conductivity ◽  
Grain Boundary ◽  
Doping Concentration ◽  
Single Phase ◽  
Precipitation Method ◽  
Molecular Water ◽  
Doped Ceria ◽  
Boundary Conductivity ◽  
Co Precipitation ◽  
Hydrated Oxide

Abstract This work aims to study the effect of Sm3+ doping concentration on the grain boundary ionic conductivity of ceria. The materials were prepared by a modified co-precipitation method, where molecular water associated with the precursor has been utilized to facilitate the hydroxylation process. The synthesized hydroxide / hydrated oxide materials were calcined and the green body (pellet) has been sintered at high temperature in order to achieve highly dense (~ 96 %) pellet. The structural analyses were done using XRD and Raman spectroscopy, which confirm the single phase cubic structure of samaria doped ceria (SDC) nanoparticles and the surface morphology of sintered samples was studied using FESEM. The ionic conductivity was measured by AC impedance spectroscopy of the sintered pellets in the temperature range of 400-700 °C, which shows superior grain boundary conductivity. The grain boundary ionic conductivity of around 0.111 S/cm has been obtained for 15SDC composition at 600 °C.

scholarly journals The Internal Friction of Single Crystals, Bicrystals and Polycrystals of Pure Magnesium

2015 ◽  
Vol 60 (1) ◽  
pp. 371-375 ◽  
Author(s):  
W.B. Jiang ◽  
Q.P. Kong ◽  
L.B. Magalas ◽  
Q.F. Fang
Keyword(s):  
Activation Energy ◽  
Internal Friction ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Room Temperature ◽  
Internal Friction Peak ◽  
Self Diffusion ◽  
Boundary Relaxation ◽  
The Difference

Abstract The internal friction of magnesium single crystals, bicrystals and polycrystals has been studied between room temperature and 450°C. There is no internal friction peak in the single crystals, but a prominent relaxation peak appears at around 160°C in polycrystals. The activation energy of the peak is 1.0 eV, which is consistent with the grain boundary self-diffusion energy of Mg. Therefore, the peak in polycrystals can be attributed to grain boundary relaxation. For the three studied bicrystals, the grain boundary peak temperatures and activation energies are higher than that of polycrystals, while the peak heights are much lower. The difference between the internal friction peaks in bicrystals and polycrystals is possibly caused by the difference in the concentrations of segregated impurities in grain boundaries.

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