First-Principles Calculation of Intermetallics on Novel Anode Materials

2013 ◽  
Vol 815 ◽  
pp. 73-79
Author(s):  
Jin Zhang ◽  
Pei Xian Zhu ◽  
Sheng Gang Zhou ◽  
Jia Xin Guo
Keyword(s):  
First Principles ◽  
Anode Materials ◽  
Electrode Materials ◽  
Formation Enthalpy ◽  
Layered Composite ◽  
Binding Energies ◽  
First Principles Calculation ◽  
Diffusion Welding ◽  
Composite Interface ◽  
Thermal Pressing

Our team proposes the design concept of layered composite electrode materials. Change the single substrate of traditional electrode material by using thermal pressing diffusion welding to synthesize sandwich structure electrode substrate of titanium cladding aluminum. Only Al3Ti phase is obtained in the composite interface. First-principles calculations have been used to calculate the formation enthalpy and binding energies, and the respective order of their value are as follows: AlTi3<AlTi<Al2Ti<Al3Ti,AlTi3<AlTi<Al2Ti<Al3Ti. AlTi3 near Fermi surface is zero and it has good conductivity. It has the strongest bonding capability and stability. Practical application of this new anode in the field of hydrometallurgy has good conductivity, strong adaptability.

Application of ANSYS in Electric Field Distribution of Ti-Al Layered Composite Materials

2012 ◽  
Vol 583 ◽  
pp. 167-170
Author(s):  
Sheng Gang Zhou ◽  
Pei Xian Zhu
Keyword(s):  
Composite Materials ◽  
Current Distribution ◽  
Electrode Materials ◽  
Energy Dispersive Spectrometer ◽  
Reaction Diffusion ◽  
Layered Composite ◽  
Diffusion Welding ◽  
The Matrix ◽  
Sandwich Type ◽  
Uniform Current

This paper changed the matrix structure model of traditional electrode materials from the the composition of the internal structure of the matrix, used solid-solid compound method of hot pressing diffusion welding for sandwich type structure Ti-Al layered composite materials, The Ti/IrO2-Ta2O5 were got by typical oxygen evolution model coating ingredient(mole ratio of Ir to Ta was 7:3). Microstructure of the layered composite materials was studied by scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS), and then the current distribution performance as the anode material for nickel electrowinning in NiSO4-H2SO4 system was characterized by electric analysis module of ANSYS program . The results showed that, The findings indicate that the interface formation of Ti-Al layered composite materials was a reaction-diffusion process. In the technology conditions of this subject, the phase of interface was Al3Ti. Compared with the traditional DSA (Dimensionally Stable Anode) titanium anode, the Ti-Al layered composite anode showed a more uniform current distribution performance.

scholarly journals Effects of Doped Elements (Si, Cr, W and Nb) on the Stability, Mechanical Properties and Electronic Structures of MoAlB Phase by the First-Principles Calculation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4221
Author(s):  
Yongxin Jian ◽  
Zhifu Huang ◽  
Yu Wang ◽  
Jiandong Xing
Keyword(s):  
Mechanical Properties ◽  
Chemical Bonding ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Elemental Doping ◽  
The Stability ◽  
W Doping

First-principles calculations based on density functional theory (DFT) have been performed to explore the effects of Si, Cr, W, and Nb elements on the stability, mechanical properties, and electronic structures of MoAlB ternary boride. The five crystals, with the formulas of Mo4Al4B4, Mo4Al3SiB4, Mo3CrAl4B4, Mo3WAl4B4, and Mo3NbAl4B4, have been respectively established. All the calculated crystals are thermodynamically stable, according to the negative cohesive energy and formation enthalpy. By the calculation of elastic constants, the mechanical moduli and ductility evolutions of MoAlB with elemental doping can be further estimated, with the aid of B/G and Poisson’s ratios. Si and W doping cannot only enhance the Young’s modulus of MoAlB, but also improve the ductility to some degree. Simultaneously, the elastic moduli of MoAlB are supposed to become more isotropic after Si and W addition. However, Cr and Nb doping plays a negative role in ameliorating the mechanical properties. Through the analysis of electronic structures and chemical bonding, the evolutions of chemical bondings can be disclosed with the addition of dopant. The enhancement of B-B, Al/Si-B, and Al/Si-Mo bondings takes place after Si substitution, and W addition apparently intensifies the bonding with B and Al. In this case, the strengthening of chemical bonding after Si and W doping exactly accounts for the improvement of mechanical properties of MoAlB. Additionally, Si doping can also improve the Debye temperature and melting point of the MoAlB crystal. Overall, Si element is predicted to be the optimized dopant to ameliorate the mechanical properties of MoAlB.

scholarly journals Thermodynamic properties of 2H-MoSe2 from first principles quasi-harmonic approximation

2020 ◽  
Vol 21 (3) ◽  
pp. 478-485
Author(s):  
O. Vasiliev
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Harmonic Approximation ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Data Sets ◽  
Calculation Results ◽  
Satisfactory Approximation

In this paper, we report the results of first-principles calculation of 2H-MoSe2 thermodynamic properties within the quasi-harmonic approximation. The focus of the article is on the temperature dependencies of the heat capacity up to 1000 ℃ and values of enthalpy of formation, enthalpy, and entropy at 298,15 K, and their comparative analysis with the existing experimental data. The results show good general agreement with the published experimental data sets allowing to use them as arbitration of existing discrepancies. Increasing deviations of the heat capacity above the room temperature suggest that factors not included in the quasi-harmonic approximation, such as vibrational anharmonicity, may have a significant influence on the thermodynamics of 2H-MoSe2 in this temperature region. Considering the inconclusive high-temperature data from the experiment, the present results may be recommended as a satisfactory approximation until the appearance of more reliable experimental data or calculation results, taking into account more finite-temperature effects.

scholarly journals The Evaluation of Mg-Ga Compounds as Electrode Materials for Mg-Ion Batteries via Ab Initio Simulation

2021 ◽  
Author(s):  
Chao Song ◽  
Yuan Yuan ◽  
Dachong Gu ◽  
Tao Chen ◽  
Yuping Liu ◽  
...  
Keyword(s):  
First Principles ◽  
Anode Materials ◽  
Electrode Materials ◽  
High Capacity ◽  
Structure Evolution ◽  
Kinetic Properties ◽  
First Principles Calculations ◽  
Alloy Type ◽  
Magnesium Ion Batteries ◽  
Fast Ion

Abstract The Mg-Ga alloy-type electrode is one of the potential anode materials for Magnesium-ion batteries (MIBs). In this work, the thermodynamic, electrochemical and kinetic properties of Mg-Ga compounds, i.e. Mg2Ga5, MgGa2, MgGa, Mg2Ga and Mg5Ga2, have been systematically studied. Combining the first-principles calculations and charge-discharge experimental results, the structure evolution and voltage curves of Mg-Ga compounds are presented, where the Mg-Ga compounds show low voltages and high capacity up to 1922 mAh·g-1 with Mg5Ga2. Additionally, the diffusion barriers of Mg in Mg-Ga alloys are low, which is favorable for the fast ion-transmission and then good rate performance as anodes of MIBs.

scholarly journals First Principles Insights into Amorphous Mg2Sn Alloy Anode for Mg-ion Batteries

2018 ◽  
Author(s):  
Majid Mortazavi ◽  
Edmund Soon ◽  
Nikhil V. Medhekar
Keyword(s):  
Amorphous Phase ◽  
First Principles ◽  
High Performance ◽  
Structural Changes ◽  
Electrode Materials ◽  
First Principles Calculation ◽  
Electronic Charge ◽  
Similar Reaction ◽  
Alloy Anode ◽  
Electrochemical Capacity

<p>Rechargeable Mg-ion batteries (MIBs) are an advantageous alternative solution to Li-ion batteries in many ways. Mg is safer and abundant in the Earth, and has a high electrochemical capacity owing to its divalent nature. It is yet relatively less studied largely due to primal success of Li-base batteries and challenges associated with the design of MIBs including high performance electrode materials. Herein, using first principles calculation, we study the electrochemical and mechanical properties of the most viable alloy anode Mg<sub>2</sub>Sn with special attention to its amorphous phase—unavoidable phase forming during cyclic Sn magnesiation in MIBs due to volume changes. We create amorphous Mg<sub>2</sub>Sn via simulated annealing technique using <i>ab initio</i> molecular dynamics. We find while Mg<sub>2</sub>Sn undergoes a substantial atomic-level structural changes during the crystal-to-amorphous transformation, its polycrystalline properties degrade slightly and become softer by only 20 % compared to the crystal phase. Moreover, we predict competitive electrochemical properties for the amorphous phase assuming it goes under similar reaction path as the average electronic charge on Mg ions almost remain unaffected. This work thus not only demonstrate that a-Mg<sub>2</sub>Sn phase could be a bypass to combat the challenges associated with the crystal cracking during volume change, but also serves as first step to better understand the widely used Mg<sub>2</sub>Sn alloy anode in MIBs.</p>

scholarly journals First-Principles Design of Rutile Oxide Heterostructures for Oxygen Evolution Reactions

2021 ◽  
Vol 9 ◽  
Author(s):  
Hyeong Yong Lim ◽  
Sung O Park ◽  
Su Hwan Kim ◽  
Gwan Yeong Jung ◽  
Sang Kyu Kwak
Keyword(s):  
Oxygen Evolution ◽  
Transition Metal Oxides ◽  
First Principles ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Oxide Heterostructures

The oxygen evolution reaction (OER) plays a key role in the determination of overall water-splitting rate. Lowering the high overpotential of the OER of transition metal oxides (TMOs), which are used as conventional OER electrocatalysts, has been the focus of many studies. The OER activity of TMOs can be tuned via the strategic formation of a heterostructure with another TMO substrate. We screened 11 rutile-type TMOs (i.e., MO2; M = V, Cr, Mn, Nb, Ru, Rh, Sn, Ta, Os, Ir, and Pt) on a rutile (110) substrate using density functional theory calculations to determine their OER activities. The conventional volcano approach based on simple binding energies of reaction intermediates was implemented; in addition, the electrochemical-step symmetry index was employed to screen heterostructures for use as electrode materials. The results show that RuO2 and IrO2 are the most promising catalysts among all candidates. The scaling results provide insights into the intrinsic properties of the heterostructure as well as materials that can be used to lower the overpotential of the OER.

scholarly journals The Bonding Mechanism of the Micro-Interface of Polymer Coated Steel

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3052
Author(s):  
Jiyang Liu ◽  
Qingdong Zhang ◽  
Boyang Zhang ◽  
Mingyang Yu
Keyword(s):  
First Principles ◽  
Md Simulation ◽  
Layered Composite ◽  
Binding Energies ◽  
Bonding Mechanism ◽  
Coated Steel ◽  
Base Interaction ◽  
Surface Hydroxyl ◽  
Calculation Results ◽  
Acid Base Interaction

As food and beverages require more and more green and safe packaging products, the emergence of polymer coated steel (PCS) has been promoted. PCS is a layered composite strip made of metal and polymer. To probe the bonding mechanism of PCS micro-interface, the substrate tin-free steel (TFS) was physically characterized by SEM and XPS, and cladding polyethylene terephthalate (PET) was simulated by first-principles methods of quantum mechanics (QM). We used COMPASS force field for molecular dynamics (MD) simulation. XPS pointed out that the element composition of TFS surface coating is Cr(OH)3, Cr2O3 and CrO3. The calculation results of MD and QM indicate that the chromium oxide and PET molecules compound in the form of acid-base interaction. The binding energies of Cr2O3 (110), (200), and (211) with PET molecules are −13.07 eV, −2.74 eV, and −2.37 eV, respectively. We established a Cr2O3 (200) model with different hydroxyl concentrations. It is proposed that the oxygen atom in C=O in the PET molecule combines with –OH on the surface of TFS to form a hydrogen bond. The binding energy of the PCS interface increases with the increase of the surface hydroxyl concentration of the TFS. It provides theoretical guidance and reference significance for the research on the bonding mechanism of PCS.

Electronic structure and phase stability of In-free photovoltaic semiconductors, Cu2ZnSnSe4 and Cu2ZnSnS4 by first-principles calculation

2009 ◽  
Vol 1165 ◽  
Author(s):  
Tsuyoshi Maeda ◽  
Satoshi Nakamura ◽  
Takahiro Wada
Keyword(s):  
Electronic Structure ◽  
Plane Wave ◽  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Enthalpies Of Formation ◽  
Functional Formalism ◽  
The Difference

AbstractWe have theoretically evaluated the phase stability and electronic structure of Cu2ZnSnSe4 (CZTSe) and Cu2ZnSnS4 (CZTS). The enthalpies of formation for kesterite, stannite and wurtz-stannite phases of CZTSe and CZTS were calculated using a plane-wave pseudopotential method within the density functional formalism. For CZTSe, the calculated formation enthalpy (ΔH) of the kesterite phase (−312.7 kJ/mol) is a little smaller than that of the stannite phase (−311.3 kJ/mol) and much smaller than that of the wurtz-stannite phase (−305.7 kJ/mol). For CZTS, the ΔH of the kesterite phase (−361.9 kJ/mol) is smaller than that of the stannite phase (−359.9 kJ/mol) and much smaller than that of the wurtz-stannite phase (−354.6 kJ/mol). The difference of ΔH between the kesterite and stannite phases for CZTS is greater than that for CZTSe. This indicates the kesterite phase is more stable than the stannite phase in CZTS compared with CZTSe. The valence band maximums (VBMs) of both the kesterite- and stannite-type CZTSe(CZTS) are antibonding orbitals of Cu 3d and Se 4p (S 3p). The conduction band minimums (CBMs) are antibonding orbitals of Sn 5s and Se 4p (S 3p). The Zn atom does not affect the VBM or the CBM in either CZTSe(CZTS). The theoretical band gap of the kesterite phase calculated with sX-LDA in both CZTSe and CZTS is a little wider than that of the wurtz-stannite phase and much wider than that of the stannite phase.

First Principles Calculation of Cooperative Atom Migration in L12 Ni3Al

2000 ◽  
Vol 646 ◽  
Author(s):  
H. Schweiger ◽  
R. Podloucky ◽  
W. Wolf ◽  
W. Püschl ◽  
W. Pfeiler
Keyword(s):  
First Principles ◽  
Activation Enthalpy ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Simultaneous Action ◽  
Fast Process ◽  
High Activation ◽  
Atom Migration ◽  
Remarkable Agreement ◽  
Regular Position

ABSTRACTRecent Monte-Carlo simulations of order relaxations in L12-ordered Ni3Al reproduced the simultaneous action of two processes as experimentally observed by residual resistometry. It was shown that the fast process is related to the fast annihilation/creation of nearest neighbour antisite pairs. These findings are now strongly corroborated by a new supercell approach of ab initio quantum mechanical calculations describing the simultaneous displacement of Ni and Al atoms on their way to their respective antisite positions. Studies of single jumps suggest that such a cooperative migration of Ni and Al is necessary in order to prevent Al antisites from jumping back into their regular position. Relaxation of neighbouring atoms was taken into account. Thus, a minimum migration barrier of about 3 eV was derived which together with the calculated formation enthalpy of a Ni vacancy of 1.5 eV amounts to 4.5 eV, in remarkable agreement with the high activation enthalpy of 4.6 eV as observed experimentally.

scholarly journals First-Principles Density Functional Theory Study of Modified Germanene-Based Electrode Materials

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 103
Author(s):  
Xue Si ◽  
Weihan She ◽  
Qiang Xu ◽  
Guangmin Yang ◽  
Zhuo Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Electrode Materials ◽  
Layer Structure ◽  
Localized States ◽  
First Principles Calculation ◽  
Quantum Capacitance ◽  
Multilayered Structures ◽  
Functional Theory

Germanene, with a wrinkled atomic layer structure and high specific surface area, showed high potential as an electrode material for supercapacitors. According to the first-principles calculation based on Density Functional Theory, the quantum capacitance of germanene could be significantly improved by introducing doping/co-doping, vacancy defects and multilayered structures. The quantum capacitance obtained enhancement as a result of the generation of localized states near the Dirac point and/or the movement of the Fermi level induced by doping and/or defects. In addition, it was found that the quantum capacitance enhanced monotonically with the increase of the defect concentration.

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