scholarly journals First-Principles Study of the Structural Stability and Dynamic Properties of Li2MSiO4 (M = Mn, Co, Ni) Polymorphs

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Ponniah Vajeeston ◽  
Federico Bianchini ◽  
Helmer Fjellvåg
Keyword(s):  
Structural Stability ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
First Principles Calculations ◽  
Li Ion Batteries ◽  
Functional Theory ◽  
Li Ion

In recent years, the scientific community has shown an increasing interest in regards to the investigation of novel materials for the intercalation of lithium atoms, suitable for application as cathodes in the new generations of Li-ion batteries. Within this framework, we have computed the relative structural stability, the electronic structure, the elastic and dynamic properties of Li2MSiO4 compounds (M = Mn, Co, Ni) by means of first-principles calculations based on density functional theory. The so-obtained structural parameters of the examined phases are in agreement with previous reports. The energy differences between different polymorphs are found to be small, and most of these structures are dynamically stable. The band structures and density of states are computed to analyse the electronic properties and characterise the chemical bonding. The single crystal elastic constants are calculated for all the examined modifications, proving their mechanical stability. These Li2MSiO4 materials are found to present a ductile behaviour upon deformation. The diffusion coefficients of Li ions, calculated at room temperature for all the examined modifications, reveal a poor conductivity for this class of materials.

First-principles calculations of stability, electronic and elastic properties of the precipitates present in 7055 aluminum alloy

2018 ◽  
Vol 32 (09) ◽  
pp. 1850104 ◽  
Author(s):  
Cheng Huang ◽  
Hongbang Shao ◽  
Yunlong Ma ◽  
Yuanchun Huang ◽  
Zhengbing Xiao
Keyword(s):  
Aluminum Alloy ◽  
Elastic Properties ◽  
Structural Stability ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Structural Parameters ◽  
First Principles Calculations ◽  
Functional Theory ◽  
7055 Aluminum Alloy

The structural stability, electronic structures and elastic properties of the strengthening precipitates, namely Al3Zr, MgZn2, Al2CuMg and Al2Cu, present in 7055 aluminum alloy were investigated by the first-principles calculations based on density functional theory (DFT). The optimized structural parameters are in good agreement with literature values available. It is found that Al3Zr has the strongest alloying ability and structural stability, while for MgZn2, its structural stability is the worst. The calculated electronic results indicate that covalent bonding is the dominant cohesion of Al3Zr, whereas the fractional ionic interactions coexisting with metallic bonding are found in MgZn2, Al2CuMg and Al2Cu. The elastic constants C[Formula: see text] of these precipitates were calculated, and the bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and universal elastic anisotropy were derived. It is suggested that MgZn2 is ductile, whereas Al3Zr, Al2CuMg and Al2Cu are brittle, and the elastic anisotropies of them increase in the following sequence: Al3Zr[Formula: see text]MgZn2[Formula: see text]Al2CuMg[Formula: see text]Al2Cu. The formation of MgZn2 and Al3Zr should be promoted by increasing the compositions of Zn and Zr to improve the alloy’s performance further.

First-principles calculations of the structural, elastic, mechanical, electronic and optical properties of monoclinic Hf4CuSi4

2020 ◽  
Vol 34 (06) ◽  
pp. 2050035
Author(s):  
Xia Xu ◽  
Wei Zeng ◽  
Fu-Sheng Liu ◽  
Zheng-Tang Liu ◽  
Qi-Jun Liu
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Elastic Anisotropy ◽  
Structural Parameters ◽  
Functional Theory ◽  
Text Structures ◽  
Structure Density

In this paper, the structural, electronic, elastic, mechanical and optical properties of monoclinic [Formula: see text] are studied using the first-principles density functional theory (DFT). The calculated structural parameters are consistent with the experimental data. The elastic constants of [Formula: see text] structures are calculated, indicating that [Formula: see text] shows mechanical stability and elastic anisotropy. According to the [Formula: see text] and Poisson’s ratio, monoclinic [Formula: see text] shows a brittle manner. The energy band structure, density of states, charge transfers and bond populations are given. And the band structure shows that the material is a metal conductor. Moreover, the optical properties and optical anisotropy of [Formula: see text] are shown and analyzed.

Computational and Experimental investigation of Nalipoite-Li2APO4 (A = Na, K) electrolytes for Li-ion batteries

2015 ◽  
Vol 1740 ◽  
Author(s):  
G. F. Ortiz ◽  
M C. López ◽  
M.E. Arroyo-de Dompablo ◽  
José L. Tirado
Keyword(s):  
Energy Barrier ◽  
Density Functional ◽  
Ionic Mobility ◽  
First Principles Calculations ◽  
Li Ion Batteries ◽  
Ionic Conductors ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Li Ion ◽  
Calculated Energy Barrier

ABSTRACTThe potential ionic conductors Li2APO4 (A = Na, K) are investigated combining experiments and first principles calculations at the Density Functional Theory level. A high ionic conductivity of 6.5 x10−6 and 1.5 x10−5 S cm−1 at 25 and 70°C, respectively, is found in Nalipoite-Li2NaPO4. For this mixed phosphate the energy barriers to Li motion are calculated. The lower energy barrier (0.7 eV) implies the inter-chain diffusion of Li in the b-c plane. We predict that ionic mobility is enhanced in the isostructural Li2KPO4, with the lowest calculated energy barrier being 0.4 eV.

scholarly journals Elastic Properties and Electronic Properties of MxNy (M = Ti, Zr) from First Principles Calculations

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1640 ◽  
Author(s):  
Yangqi Ji ◽  
Xiaoli Yuan
Keyword(s):  
Electronic Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Central Force ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Space Group ◽  
Group I

The elastic properties and electronic properties of MxNy (M = Ti, Zr) TiN, Ti2N, Zr3N4, ZrN with different structures have been investigated using density functional theory. Through the calculation of the elastic constants, it was found that all of these structures meet the mechanical stability except for ZrN with space group P63mc. Their mechanical properties are studied by a comparison of various parameters. The stiffness of TiN is larger than that of ZrN with space group Fm 3 ¯ m. Ti2N’s stiffness with space group I41/amdz is larger than Ti2N with space group P42/mnm. Zr3N4’s stiffness with space group Pnam is largest in three structures of Zr3N4. TiN, Ti2N and ZrN are non-central force, Zr3N4 is central force. TiN and ZrN with space group Fm 3 ¯ m are brittle, and TiN is brittler than ZrN with space group Fm 3 ¯ m. The two kinds of Ti2N are brittle and Ti2N with space group I41/amdz is larger. Three structures of Zr3N4 are tough and Zr3N4 with space group I 4 ¯ 3d is the toughest. Meanwhile, the electronic properties of TiN, Ti2N, Zr3N4 and ZrN were calculated, possible superconducting properties of the studied materials were predicted.

Electronic, Optical and Vibrational Properties of B3N3H6 from First-Principles Calculations

2021 ◽  
Author(s):  
Yun-Dan Gan ◽  
Han Qin ◽  
Fu-Sheng Liu ◽  
Zheng-Tang Liu ◽  
Cheng lu Jiang ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Vibrational Properties ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Conductivity Loss ◽  
Good Agreement

Abstract The electronic, optical and vibrational properties of B3N3H6 have been calculated by means of first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B3N3H6 are in good agreement with experimental work. With the band structure and density of states (DOS), we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function and reflectivity. By the contrast, it is found that on the (001) component and (100) component have obvious optical anisotropy. Moreover, the vibrational properties have been obtained and analyzed.

scholarly journals The elusive magnetic ground state of sodium superoxide (NaO2)

2021 ◽  
Author(s):  
Sarajit Biswas ◽  
Molly De Raychaudhury
Keyword(s):  
Ground State ◽  
First Principles ◽  
Alternative Energy ◽  
Density Functional ◽  
Structural Phase ◽  
Li Ion Batteries ◽  
Structural Phase Transitions ◽  
Magnetic Ground State ◽  
Functional Theory ◽  
Li Ion

Abstract An alternative energy storage solution to Li-ion batteries is a higher alkali metal superoxide, namely NaO2. It is well-known that the transport properties of this alkali superoxide are governed by the transfer of charge between O2 dimers. Although it goes through a plethora of structural phase transitions, its electronic and magnetic ground state remains shrouded. In this work, we perform first-principles density functional theory (DFT) calculations in order to understand the electronic structure, the source of the ‘unconventional’ magnetic properties and its effect on conductivity in Na superoxide. Finally, we explore the connection between magnetogyration and the magnetic ground state of NaO2 remaining undetected till date.

Elastic Properties and Electronic Structures of L12-TiAl3 and L12-Ti(Al,Pt)3: A Density Functional Theory Investigation

2015 ◽  
Vol 817 ◽  
pp. 816-825
Author(s):  
Bo Huang ◽  
Yong Hua Duan ◽  
Sun Yong ◽  
Ming Jun Peng
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Structural Parameters ◽  
First Principles Calculations ◽  
Elastic Parameters ◽  
Electronic Density ◽  
Functional Theory ◽  
Experimental Values

First-principles calculations have been carried out to investigate the elastic properties and electronic structures of L12-TiAl3and L12-Ti (Al, Pt)3. The optimized structural parameters were largely consistent with the experimental values. The electronic density of states (DOS) and the differences of charge density distribution were given. The independent single-crystal elastic constants and polycrystalline elastic parameters such as bulk modulusB, Young’s modulusE, shear modulusG, Poisson’s ratioνand anisotropy valueAhave been calculated by Voigt-Reuss-Hill averaging scheme. The results indicate that the L12-Ti (Al, Pt)3exhibits larger anisotropy and more ductile than L12-TiAl3.

First-principles study on the electronic structure and elastic properties of Mo2NiB2 doped with V

2018 ◽  
Vol 32 (10) ◽  
pp. 1850065 ◽  
Author(s):  
Jinming Li ◽  
Xiaobo Li ◽  
Haiyun Gao ◽  
Dian Peng
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Formation Enthalpy ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Ternary Boride

The content of this study is to analyze the electronic structure and elastic properties that the different structures of Mo2NiB2 and doping with V of the tetragonal M3B2 (Mo2Ni[Formula: see text]V[Formula: see text]B2 and Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2) (x = 0.25, 0.5, 0.75 and y = 0.125, 0.25, 0.375) by first-principles calculations based on density functional theory (DFT) combined with the projection-plus-wave method. But the calculated formation energy shows that V atoms prefer to substitute the Mo and Ni atoms of the tetragonal Mo2NiB2. Moreover, with the increase of V content, the formation enthalpy of tetragonal Mo2NiB2 is reduced, and the formation enthalpy of Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2 is the least as −53.23 kJ/mol. The calculated elastic constant suffices the condition of mechanical stability, indicate that they are stable. The calculated elastic modulus illustrates that Mo2NiB2 having better mechanical properties when V elements are at Mo and Ni sites instead of Ni sites. The calculated and analyzed density of states of Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2 has the smallest the density of states at the Fermi level indicating that it has the more stable structure. For the theoretical analysis of the first-principles calculations, the addition of 15 atom% of the V and V doping modes of Mo and Ni are preferentially replaced by V atoms of Mo2NiB2 ternary boride has the best performance.

First-Principles Investigations of Electronic, Dynamic and Thermodynamic Properties of α-MnO2

2014 ◽  
Vol 936 ◽  
pp. 591-595 ◽  
Author(s):  
Ai Min Hao ◽  
Na Qi Wang
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Dynamic Properties ◽  
Thermodynamic Quantities ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Direct Band Gap ◽  
Direct Band

We investigate the electronic, dynamic and thermodynamic properties of α-MnO2 using first-principles calculations based on density functional theory (DFT) with the GGA+U method. The results of electronic structures show that α-MnO2is a semiconductor with a direct band gap of 1.4 eV at Γ point. The results of dynamic properties indicate that the structure of α-MnO2 is dynamically unstable at ground-state. Several important thermodynamic quantities, such as entropy, enthalpy and Gibbs free energy, et al each as a function of temperature were presented.

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