scholarly journals Effect of zinc doping on electrical properties of LaAlO3 perovskite

2021 ◽  
Vol 8 (1) ◽  
pp. 20218103
Author(s):  
Anastasia V. Egorova ◽  
Ksenia G. Belova ◽  
Irina E. Animitsa ◽  
Yelizaveta A. Morkhova ◽  
Artem A. Kabanov
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Density Functional ◽  
Electronic Conductivity ◽  
High Energy ◽  
Homogeneity Region ◽  
Partial Substitution ◽  
Cubic Symmetry ◽  
Order Of Magnitude ◽  
P Type

New solid solution with the general formula of LaAl1-xZnxO3-1/2x was prepared by a solid-state reaction route. According to XRD, the crystal structure of LaAlO3 is rhombohedral, while the solid solution possesses cubic symmetry. Homogeneity region of the solid solution LaAl1-xZnxO3-1/2x was narrow and limited to the maximum concentration of 5 mol. %. Computer simulations using crystalochemistry and density functional theory approaches showed that LaAlO3 has high energy barriers for O2–-ion transport (2.79 eV). These results are in good agreement with the low values of electrical conductivity obtained experimentally. The electrical conductivity of LaAl1-xZnxO3-1/2x was measured by impedance spectroscopy in the temperature range of 200–1000 °C. The partial substitution of Al3+ by Zn2+ was found to increase the electrical conductivity by ~2 order of magnitude. The electrical conductivity of doped phase LaAl0.95Zn0.05O2.975 as a function of oxygen partial pressure was measured, and the partial contributions (oxygen-ionic and electronic) were determined. It was found that the sample has mixed ionic and p-type electronic conductivity, while the electronic contribution increases with the rise of the temperature.

scholarly journals Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-

2019 ◽  
Vol 53 (6) ◽  
pp. 751
Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Wide Temperature Range ◽  
Figure Of Merit ◽  
Nanostructured Material ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
P Type

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.

Thermal Decomposition of Supersaturated Ti1-xAlxN Solid Solution Synthesized by High-Energy Milling

2016 ◽  
Vol 9 ◽  
pp. 82-89
Author(s):  
Maya Radune ◽  
Michael Zinigrad ◽  
David Fuks ◽  
S. Hayun ◽  
Nachum Frage
Keyword(s):  
Thermal Stability ◽  
Solid Solution ◽  
Spinodal Decomposition ◽  
Density Functional ◽  
Chemical Deposition ◽  
High Energy ◽  
Nucleation And Growth ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Thermal Stability Of

Supersaturated titanium-aluminum nitride (Ti1-xAlxN) is a very attractive material for a wide range of applications due to its high oxidation and wear resistance accompanied by high strength, hardness, thermal conductivity and thermal shock resistance. Currently, its applications are limited to coatings obtained by physical or chemical deposition. Bulk materials based on Ti1-xAlxN may be fabricated by powder metallurgy approach using powders synthesized by high-energy ball milling (HEBM), which composition corresponds to supersaturated Ti1-xAlxN solid solution. In the present study, thermal stability of the supersaturated Ti1-xAlxN solid solution was investigated. According to the quasi-binary TiN-AlN phase diagram, constructed using density functional theory (DFT) analysis, the concentration ranges, where decomposition takes place through spinodal decomposition or through nucleation and growth, were determined. Experimental study on thermal stability of solid Ti1-xAlxN solution powder was conducted by means of differential scanning calorimetry (DSC), Brunauer-Emmited-Teller (BET) and XRD. The results indicated that spinodal decomposition of Ti1-xAlxN starts at 800°C, while at temperature higher than 1300°C regular decomposition (nucleation and growth) is occur.

scholarly journals Preparation and electrical conductivity of (Cu0.5Ag0.5)7SiS5I-based superionic ceramics

2020 ◽  
Author(s):  
Ihor Studenyak ◽  
Artem POGODIN ◽  
Iryna SHENDER ◽  
Serhiy BEREZNYUK ◽  
Mykhailo FILEP ◽  
...  
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Electronic Conductivity ◽  
Microstructural Analysis ◽  
Structural Studies ◽  
Frequency Range ◽  
Electronic Components ◽  
Total Electrical Conductivity ◽  
Ceramic Samples ◽  
Average Size

Abstract The ceramics based on (Cu0.5Ag0.5)7SiS5I solid solution of superionic conductor with argyrodite structure were prepared by using the powders with different particles size. The structural studies of powders were performed by XRD technique, while the ceramic samples with different average size of the crystallites were investigated by microstructural analysis. The total electrical conductivity of ceramic samples was measured by impedance spectroscopy in the frequency range from 10 Hz to 2×106 Hz and temperature interval from 292 K to 383 K. The contributions of ionic and electronic components into the total electrical conductivity were separated as well as their temperature behavior was studied. The dependences of ionic and electronic conductivity and their activation energies on average size of the crystallites in (Cu0.5Ag0.5)7SiS5I-based ceramic samples were investigated.

scholarly journals Higher thermoelectric performance of Zintl phases (Eu0.5Yb0.5)1−xCaxMg2Bi2 by band engineering and strain fluctuation

2016 ◽  
Vol 113 (29) ◽  
pp. E4125-E4132 ◽  
Author(s):  
Jing Shuai ◽  
Huiyuan Geng ◽  
Yucheng Lan ◽  
Zhuan Zhu ◽  
Chao Wang ◽  
...  
Keyword(s):  
Density Functional ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Thermoelectric Performance ◽  
Partial Substitution ◽  
Zintl Phases ◽  
Band Engineering ◽  
Transmission Electron ◽  
P Type ◽  
Callaway Model

Complex Zintl phases, especially antimony (Sb)-based YbZn0.4Cd1.6Sb2 with figure-of-merit (ZT) of ∼1.2 at 700 K, are good candidates as thermoelectric materials because of their intrinsic “electron–crystal, phonon–glass” nature. Here, we report the rarely studied p-type bismuth (Bi)-based Zintl phases (Ca,Yb,Eu)Mg2Bi2 with a record thermoelectric performance. Phase-pure EuMg2Bi2 is successfully prepared with suppressed bipolar effect to reach ZT ∼ 1. Further partial substitution of Eu by Ca and Yb enhanced ZT to ∼1.3 for Eu0.2Yb0.2Ca0.6Mg2Bi2 at 873 K. Density-functional theory (DFT) simulation indicates the alloying has no effect on the valence band, but does affect the conduction band. Such band engineering results in good p-type thermoelectric properties with high carrier mobility. Using transmission electron microscopy, various types of strains are observed and are believed to be due to atomic mass and size fluctuations. Point defects, strain, dislocations, and nanostructures jointly contribute to phonon scattering, confirmed by the semiclassical theoretical calculations based on a modified Debye–Callaway model of lattice thermal conductivity. This work indicates Bi-based (Ca,Yb,Eu)Mg2Bi2 is better than the Sb-based Zintl phases.

scholarly journals Synthesis and Electrochemical Properties of Bi2MoO6/Carbon Anode for Lithium-Ion Battery Application

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1132 ◽  
Author(s):  
Tingting Zhang ◽  
Emilia Olsson ◽  
Mohammadmehdi Choolaei ◽  
Vlad Stolojan ◽  
Chuanqi Feng ◽  
...  
Keyword(s):  
Density Functional ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
High Energy ◽  
Carbon Composite ◽  
High Energy Density ◽  
Carbon Anode ◽  
Li Ion

High capacity electrode materials are the key for high energy density Li-ion batteries (LIB) to meet the requirement of the increased driving range of electric vehicles. Here we report the synthesis of a novel anode material, Bi2MoO6/palm-carbon composite, via a simple hydrothermal method. The composite shows higher reversible capacity and better cycling performance, compared to pure Bi2MoO6. In 0–3 V, a potential window of 100 mA/g current density, the LIB cells based on Bi2MoO6/palm-carbon composite show retention reversible capacity of 664 mAh·g−1 after 200 cycles. Electrochemical testing and ab initio density functional theory calculations are used to study the fundamental mechanism of Li ion incorporation into the materials. These studies confirm that Li ions incorporate into Bi2MoO6 via insertion to the interstitial sites in the MoO6-layer, and the presence of palm-carbon improves the electronic conductivity, and thus enhanced the performance of the composite materials.

Solid solution Ca12Al14O33±δ: V5+, Mo5+

2019 ◽  
pp. 49-54
Author(s):  
A. S. Tolkacheva ◽  
S.  N. Shkerin ◽  
S. V. Plaksin ◽  
A. A. Pankratov ◽  
N. I. Moskalenko
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Impedance Spectroscopy ◽  
Temperature Dependence ◽  
Charge State ◽  
Octahedral Coordination ◽  
Order Of Magnitude ◽  
Combination Of Methods

A solid solution of the composition Ca12–x(Al14Vx)O33+δ(0 ≤ х ≤ 0,07) was synthesized. A combination of methods established the charge state of vanadium in a solid solution. The principle of filling with a dopant crystallographic positions in the structure of mayenite is proposed: vanadium cations replace a small number of aluminum positions, presumably in octahedral coordination. The temperature dependence of the electrical conductivity of Ca11,93(Al14V0,07)O33+δ was studied by the impedance spectroscopy. It is shown that doping of mayenite with vanadium increases the value of electrical conductivity by an order of magnitude.

Significantly improved conductivity of spinel Co3O4 porous nanowires partially substituted by Sn in tetrahedral sites for high-performance quasi-solid-state supercapacitors

2021 ◽  
Vol 9 (11) ◽  
pp. 7005-7017
Author(s):  
Yunjian Chen ◽  
Jia Zhu ◽  
Ni Wang ◽  
Huanyu Cheng ◽  
Xianzhong Tang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Energy Density ◽  
Electrochemical Performance ◽  
High Performance ◽  
High Energy ◽  
High Energy Density ◽  
Partial Substitution ◽  
Tetrahedral Sites ◽  
Excellent Electrochemical Performance

The partial substitution of Sn in spinel-structured Co3O4 exhibits excellent electrochemical performance, including good electrical conductivity, high energy density, power density and cycling retention, as a positive electrode for supercapacitors.

New Mixed Conductors Based on Doped Layered Perovskites

1998 ◽  
Vol 548 ◽  
Author(s):  
Carlos Navas ◽  
Harry L. Tuller ◽  
Hans-Conrad zur Loye
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Electronic Conductivity ◽  
Total Conductivity ◽  
Mixed Conductors ◽  
Type Conductivity ◽  
P Type ◽  
Layered Perovskites

ABSTRACTA series of doped Ruddlesden-Popper phases, of general formula Sr3Ti2−xMxO7−δ (M=Al, Ga, Co), were synthesized and their electrical conductivity characterized as a function of temperature and oxygen partial pressure. For fixed-valent dopants, p-type conductivity predominates at p(O2)>10−5 atm, followed by a p(O2)-independent electrolytic regime, and n-type electronic conductivity at very low p(O2). The electrolytic regime exhibits activation energies in the range 1.7-1.8 eV. Doping with transition metals such as Co results in a very significant increase in total conductivity with a p-type conductivity at high p(O2). Furthermore, an apparent ionic regime at intermediate p(O2) is observed, characterized by high conductivity (>10−2 S/cm at 700 °C) and low activation energy (0.7 eV). This interpretation is consistent with iodometric measurements as interpreted by a defect chemical model. Other measurements are in progress to confirm this conclusion.

Sign in / Sign up

Export Citation Format

Share Document