From Used Oxide Nuclear Fuel to Rechargeable Battery: A First-Principles Study

2013 ◽  
Vol 1541 ◽  
Author(s):  
Binbin Wu ◽  
Jianguo Yu
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Nuclear Reactions ◽  
Open Circuit ◽  
Functional Theory ◽  
Oxide Nuclear Fuel ◽  
Alternative Solutions ◽  
Work First ◽  
Open Circuit Voltages ◽  
Grid Storage

AbstractAlthough uranium oxides have played essential roles in many nuclear reactions, it is imperative to pursue alternative solutions to reuse the spent fuels due to paramount safety and economic concern. Spent nuclear oxide fuels include uranium dioxide (UO2), triuranium octoxide (U3O8) and uranium trioxide (UO3). In this work, first principles calculations based on density functional theory (DFT) were carried out on MUO2, MU3O8 and MUO3 (M= Li, Na and K) to explore their possibilities to serve as grid-storage-based cathode materials. In particular, the result of the optimal structures, average open circuit voltages (OCV) and mechanic stabilities during charge and discharge processes are presented. These results are also compared to available experimental data.

A combined first principles and Mohr-Coulomb criterion for the determination of the nanohardness of amorphous silicon

2015 ◽  
Vol 24 (5-6) ◽  
pp. 145-151
Author(s):  
Maryam Tabatabaei ◽  
Hossein M. Shodja
Keyword(s):  
Amorphous Silicon ◽  
First Principles ◽  
Density Functional ◽  
Electronic Charge ◽  
Functional Theory ◽  
Experimental Works ◽  
The Subject ◽  
Coulomb Criterion ◽  
Work First

AbstractAlthough, the evaluation of the nanohardness of amorphous silicon (a-Si) has been the subject of a few experimental works but, to date, it has not been addressed theoretically yet. In this work, first principles Kohn-Sham density functional theory (DFT)-based molecular dynamics (MD) in combination with Mohr-Coulomb criterion is employed to calculate the ideal shear strength of the damped MD annealed a-Si sample containing dangling and floating bonds which are pertinent to the threefold- and fivefold-coordinated defects, respectively, as well as distorted tetrahedral bonds. The stress state beneath the nanoindenter is triaxial, and is accounted for properly. The calculated values of nanohardness are in reasonable agreement with those values measured experimentally. Consideration of the electronic charge distribution under the state of triaxial tension test reveals that the yield phenomenon in a-Si is accompanied by the transformation of a threefold-coordinated Si atom to a fourfold-coordinated.

Comparative Studies on Monolayer and Bilayer Phosphorous as the Anodes of Li Ion Battery

2021 ◽  
Vol 896 ◽  
pp. 61-66
Author(s):  
Yuan Yuan
Keyword(s):  
Density Functional ◽  
Open Circuit ◽  
Binding Energies ◽  
Li Ion Battery ◽  
Ion Diffusion ◽  
Functional Theory ◽  
2D Material ◽  
Li Ion ◽  
Open Circuit Voltages ◽  
Current Report

Recently, two-dimensional (2D) material developed rapidly and provided a wide application on the anode of the batteries, reducing the adverse effect of traditional ion batteries such as low capacity, short cycle life, slow charging and poor safety mainly coming from the use of graphite anode. The current report investigates the anode performances of phosphorus, a new 2D material in electrochemistry field, with monolayer and bilayer structure for Li ion batterys (LIBs) through density functional theory (DFT) calculations and gives a comparison on the Li ion valences, binding energies and open-circuit voltages between the two structures. The results indicate that bilayer phosphorus perform better as a novel anode due to the stronger adhesion to Li and lower barrier for ion diffusion. Furthermore, our research results illustrate a broad application prospect on the new anode inventions as well as reducing useless consumption on the batteries by the practice of bilayer phosphorus anode.

Studies on the Performance of Two Dimensional AlSi as the Anodes of Li Ion Battery

2021 ◽  
Vol 324 ◽  
pp. 109-115
Author(s):  
Shuai Hao
Keyword(s):  
Density Functional ◽  
Open Circuit ◽  
Binding Energies ◽  
Two Dimensional ◽  
Ion Diffusion ◽  
Functional Theory ◽  
Charging Rate ◽  
Li Ion ◽  
Open Circuit Voltages ◽  
Current Report

Recently, two-dimensional (2D) materials have been rapidly developed and they provided a wide application on the anode of the batteries, reducing the adverse effect of traditional ion batteries including low capacity, short cycle life, low charging rate and poor safety mainly coming from the use of graphite anode. The current report investigates the anode performances of AlSi, a new 2D material exfoliated from NaAlSi, for Li ion batterys (LIBs) through density functional theory (DFT) calculations and gives quantitative discussions on the Li ion valences, binding energies and open-circuit voltages of 2D AlSi anode. The results indicate that 2D AlSi performs great as a novel anode due to the moderate adhesion to Li and low barrier for ion diffusion. Furthermore, our research results illustrate a broad application prospect on the new anode inventions as well as reducing useless consumption on the batteries by the practice of AlSi anode.

scholarly journals A First-Principles Study of the Cu-Containing β″ Precipitates in Al-Mg-Si-Cu Alloy

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7879
Author(s):  
Shaozhi He ◽  
Jiong Wang ◽  
Donglan Zhang ◽  
Qing Wu ◽  
Yi Kong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Electron Interaction ◽  
Structure Stability ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Cu Alloy ◽  
Work First

The nanostructured β″ precipitates are critical for the strength of Al-Mg-Si-(Cu) aluminum alloys. However, there are still controversial reports about the composition of Cu-containing β″ phases. In this work, first-principles calculations based on density functional theory were used to investigate the composition, mechanical properties, and electronic structure of Cu-containing β″ phases. The results predict that the Cu-containing β″ precipitates with a stoichiometry of Mg4+xAl2−xCuSi4 (x = 0, 1) are energetically favorable. As the concentration of Cu atoms increases, Cu-containing β″ phases with different compositions will appear, such as Mg4AlCu2Si4 and Mg4Cu3Si4. The replacement order of Cu atoms in β″ phases can be summarized as one Si3/Al site → two Si3/Al sites → two Si3/Al sites and one Mg1 site. The calculated elastic constants of the considered β″ phases suggest that they are all mechanically stable, and all β″ phases are ductile. When Cu atoms replace Al atoms at Si3/Al sites in β″ phases, the values of bulk modulus (B), shear modulus (G), and Young’s modulus (E) all increase. The calculation of the phonon spectrum shows that Mg4+xAl2−xCuSi4 (x = 0, 1) are also dynamically stable. The electronic structure analysis shows that the bond between the Si atom and the Cu atom has a covalent like property. The incorporation of the Cu atom enhances the electron interaction between the Mg2 and the Si3 atom so that the Mg2 atom also joins the Si network, which may be one of the reasons why Cu atoms increase the structure stability of the β″ phases.

scholarly journals Influence of “Productive” Impurities (Cd, Na, O) on the Properties of the Cu2ZnSnS4 Absorber of Model Solar Cells

2021 ◽  
Vol 58 (6) ◽  
pp. 13-23
Author(s):  
D. Sergeyev ◽  
N. Zhanturina ◽  
A. Aizharikov ◽  
A.I. Popov
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Generalized Gradient ◽  
Absorption Bands ◽  
Functional Theory ◽  
The Density Functional Theory

Abstract The study focuses on the optical properties of the CZTS multicomponent semiconductor absorber with 3 % “production” impurities of Cd, Na, O within the framework of the density functional theory using the generalized gradient approximation and the SCAPS program, as well as investigates their influence on the performance and efficiency of CZTS-solar cells. The results showed that the introduction of Cd, Na, O impurities would lead to a decrease in the intensity of the absorption bands at 2.06 eV and 2.55 eV. The density of states CZTS: (Cd, Na, O) was determined from first principles, and it was revealed that impurities of Cd and O atoms would lead to a decrease in the band gap (to 0.9 eV and 0.79 eV), and an increase in Na impurity absorption (1.2 eV). It was also found that a decrease in the band gap led to a decrease in the open circuit voltage, and it was also shown that “industrial” impurities led to a decrease in the efficiency of energy conversion of solar cells to 2.34 %.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

The Damping Term, from First Principles

2017 ◽  
Author(s):  
Olle Eriksson ◽  
Anders Bergman ◽  
Lars Bergqvist ◽  
Johan Hellsvik
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Spin Dynamics ◽  
Damping Term ◽  
Functional Theory ◽  
Basic Principles ◽  
Sham Equation ◽  
Damping Parameter ◽  
Simulation Cell

In the previous chapters we described the basic principles of density functional theory, gave examples of how accurate it is to describe static magnetic properties in general, and derived from this basis the master equation for atomistic spin-dynamics; the SLL (or SLLG) equation. However, one term was not described in these chapters, namely the damping parameter. This parameter is a crucial one in the SLL (or SLLG) equation, since it allows for energy and angular momentum to dissipate from the simulation cell. The damping parameter can be evaluated from density functional theory, and the Kohn-Sham equation, and it is possible to determine its value experimentally. This chapter covers in detail the theoretical aspects of how to calculate theoretically the damping parameter. Chapter 8 is focused, among other things, on the experimental detection of the damping, using ferromagnetic resonance.

Site preference and atomic ordering in the ternary Rh5Ga2As: first-principles calculations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nilanjan Roy ◽  
Sucharita Giri ◽  
Harshit ◽  
Partha P. Jana
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Density Functional ◽  
Structure Type ◽  
Site Preference ◽  
X Ray Diffraction ◽  
Atomic Ordering ◽  
Functional Theory ◽  
The Stability ◽  
Bonding Characteristics

Abstract The site preference and atomic ordering of the ternary Rh5Ga2As have been investigated using first-principles density functional theory (DFT). An interesting atomic ordering of two neighboring elements Ga and As reported in the structure of Rh5Ga2As by X-ray diffraction data only is confirmed by first-principles total-energy calculations. The previously reported experimental model with Ga/As ordering is indeed the most stable in the structure of Rh5Ga2As. The calculation detected that there is an obvious trend concerning the influence of the heteroatomic Rh–Ga/As contacts on the calculated total energy. Interestingly, the orderly distribution of As and Ga that is found in the binary GaAs (Zinc-blende structure type), retained to ternary Rh5Ga2As. The density of states (DOS) and Crystal Orbital Hamiltonian Population (COHP) are calculated to enlighten the stability and bonding characteristics in the structure of Rh5Ga2As. The bonding analysis also confirms that Rh–Ga/As short contacts are the major driving force towards the overall stability of the compound.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

Sign in / Sign up

Export Citation Format

Share Document