scholarly journals Ab Initio Study of Porous Graphene–CNT Silicon Composite for Li-Ion and Na-Ion Batteries

2021 ◽  
Vol 7 (3) ◽  
pp. 57
Author(s):  
Dmitry A. Kolosov ◽  
Olga E. Glukhova
Keyword(s):  
Density Functional ◽  
Specific Capacity ◽  
Transmission Function ◽  
Density Functional Theory Method ◽  
Lithium Ion ◽  
Heat Of Formation ◽  
Negative Energy ◽  
Silicon Cluster ◽  
The Density Functional Theory ◽  
Li Ion

In this work, we investigated composite materials based on graphene and carbon nanotubes with a silicon cluster from the standpoint of using them as Li-ion battery (LIB) and Na-ion battery (NIB) anodes. For our study, we used the density functional theory method, taking into account the van der Waals interaction. The cavities of the composite were filled with lithium and sodium, and the energy characteristics of the structure were calculated through SIESTA molecular dynamics. The calculations showed the negative energy of adsorption for lithium and sodium and the negative value of the heat of formation of the composites. The introduction of a silicon cluster led to an increase in the specific capacity by 22.2% for the sodium and 37% for the lithium in comparison with the pure composite. The calculation of the transmission function showed a decrease in the resistance of the composite when a silicon cluster was added to the composite. We predict that the application of the considered composite will increase the efficiency of existing lithium-ion and sodium-ion batteries.

Study of the Stability and Chemical Reactivity of a Series of Tetrazole Pyrimidine Hybrids by the Density Functional Theory Method (DFT)

2021 ◽  
Vol 37 (4) ◽  
pp. 805-812
Author(s):  
Ahissandonatien Ehouman ◽  
Adjoumanirodrigue Kouakou ◽  
Fatogoma Diarrassouba ◽  
Hakim Abdel Aziz Ouattara ◽  
Paulin Marius Niamien
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Chemical Reactivity ◽  
Density Functional Theory Method ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global Reactivity Descriptors

Our theoretical study of stability and reactivity was carried out on six (06) molecules of a series of pyrimidine tetrazole hybrids (PTH) substituted with H, F, Cl, Br, OCH3 and CH3 atoms and groups of atoms using the density function theory (DFT). Analysis of the thermodynamic formation quantities confirmed the formation and existence of the series of molecules studied. Quantum chemical calculations at the B3LYP / 6-311G (d, p) level of theory determined molecular descriptors. Global reactivity descriptors were also determined and analyzed. Thus, the results showed that the compound PTH_1 is the most stable, and PTH_5 is the most reactive and nucleophilic. Similarly, the compound PTH_4 is the most electrophilic. The analysis of the local descriptors and the boundary molecular orbitals allowed us to identify the preferred atoms for electrophilic and nucleophilic attacks.

scholarly journals Practical and Theoretical Study on the Inhibitory Influences of New Azomethine Derivatives Containing an 8-Hydroxyquinoline Moiety for the Corrosion of Carbon Steel in 1 M HCl

2018 ◽  
Vol 34 (6) ◽  
pp. 3016-3029 ◽  
Author(s):  
A. El-Yaktini ◽  
A. Lachiri ◽  
M. El-Faydy ◽  
F. Benhiba ◽  
H. Zarrok ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Density Functional Theory Method ◽  
Steel Corrosion ◽  
Experimental Results ◽  
Chemical Parameters ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Inhibition Ability

The inhibition ability of a new Azomethine derivatives containing the 8-hydroxyquinoline (BDHQ and MDHQ) towards carbon steel corrosion in HCl solution was studied at various concentrations and temperatures using weight loss, polarization curves and electrochemical impedance spectroscopy (EIS) methods. The experimental results reveal that BDHQ and MDHQ are efficient mixed type corrosion inhibitors, and their inhibition efficiencies increase with increasing concentration. The adsorption of these inhibitors on mild steel surface obeys Langmuir isotherm. Quantum chemical parameters are calculated using the Density Functional Theory method (DFT) and Monte Carlo simulations. Correlation between theoretical and experimental results is discussed.

Ab Initio Calculations of New α-L5-7a and β-L5-7a Graphyne Polymorphic Varieties

2022 ◽  
Vol 1049 ◽  
pp. 180-185
Author(s):  
Viktor Mavrinskii ◽  
Evgeniy A. Belenkov
Keyword(s):  
Density Functional ◽  
Electronic States ◽  
Density Functional Theory Method ◽  
Geometric Optimization ◽  
Initial Structure ◽  
Functional Theory ◽  
Graphene Layers ◽  
Density Of Electronic States ◽  
Sublimation Energy ◽  
The Density Functional Theory

Calculations of the structural and energy parameters, band structure and density of electronic states of new structural varieties of graphyne have been performed by the density functional theory method. The initial structure of the nine polymorphs was theoretically constructed on the basis of the 5-7a graphene layer. As a result of the calculations, the structure of only five graphyne layers was found to be stable: α-L5-7a, β1-L5-7a, β2-L5-7a, β3-L5-7a and β4-L5-7a. The structure of layers γ1-L5-7a, γ2-L5-7a, and γ3-L5-7a is transformed into the structure of graphene layers by geometric optimization, and the graphyne layer γ4-L5-7a is transformed sp+sp2 layer L3-6-13. The sublimation energy of the stable graphyne polymorphs varies from 6.66 to 6.78 eV/atom. The density of electronic states at the Fermi energy level for all α-L5-7a and β-L5-7a layers of graphyne is different from zero, so the new graphyne polymorphs should have metallic properties.

Hydrogen-Bonded Interactions in the Systems L-Cysteine - H2SeO3 and L-Cysteine -H2SeO4

2013 ◽  
pp. 169-179
Author(s):  
Alexei N. Pankratov ◽  
Nikolay A. Bychkov ◽  
Olga M. Tsivileva
Keyword(s):  
Density Functional ◽  
Density Functional Theory Method ◽  
Thiol Group ◽  
Mutual Orientation ◽  
Theory Method ◽  
Functional Theory ◽  
Compound A ◽  
The Density Functional Theory ◽  
The Enthalpy Of Formation ◽  
Hydrogen Bonded

Using the density functional theory method at the B3LYP/6-31G(d,p) level of theory, the formation of hydrogen-bonded complexes of L-cysteine with selenious and selenic acids has been studied. In both cases of selenium-containing acids, the complexes occur preferably by cysteine carboxylic group, therewith the enthalpy of formation values consist from –19 to –21 kcal/mol, and free energy from –6 to –9 kcal/mol. Probably, the initial act of interaction in the system hydroxyl-containing selenium compound - a-amino acid, proceeding with mutual orientation of the reactants molecules and intermolecular hydrogen bonds formation, serves as a prerequisite for the thiol group capability of participating in the subsequent stages (including more completed transformations) of biologically important reactions.

scholarly journals Proposed Mechanism for the High-Yield Polymerization of Oxyethyl Propiolates with Rh Complex Catalyst Using the Density Functional Theory Method

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 93 ◽  
Author(s):  
Yoshiaki Yoshida ◽  
Yasuteru Mawatari ◽  
Masayoshi Tabata
Keyword(s):  
Density Functional ◽  
Density Functional Theory Method ◽  
High Reactivity ◽  
High Yield ◽  
Complex Catalyst ◽  
Dft Methods ◽  
Functional Theory ◽  
Molecular Weights ◽  
Monomer Structure ◽  
The Density Functional Theory

In this study, poly(oxyethyl propiolate)s (POP)s featuring various oxyethylene derivatives are synthesized using a [Rh(norbornadiene)Cl]2 catalyst. In particular, POPs featuring the normal oxyethylene chain in the side-chain exhibit excellent yields and high molecular weights in methanol and N,N-dimethylformamide at 40 °C, compared with poly(n-alkyl propiolate)s (PnAP)s. The high reactivity of the oxyethyl propiolate (OP) monomers is clarified by considering the time dependences of the polymerization yields of OPs and alkyl propiolates (Aps). Furthermore, the monomer structure and intermediate conformation of the Rh complex are optimized using Density Function theory (DFT) methods (B3LYP/6-31G** and B3LYP/LANL2DZ) and a polymerization mechanism is proposed.

scholarly journals Metastable One-Electron Excited States of Charged Fullerenes

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Rafael V. Arutyunyan ◽  
Alexander D. Vasiliev ◽  
Yuri N. Obukhov ◽  
Alexander V. Osadchy
Keyword(s):  
Density Functional ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Density Functional Theory Method ◽  
Transition Dipole ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Transition Dipole Moments ◽  
Quantum Transitions ◽  
Wavelength Radiation

We study the spontaneous emission processes for the quantum transitions between electron states of a charged C60 fullerene. Lifetimes for the transitions between the volume-localized electron levels and the surface-localized electron levels are evaluated and compared with the transitions between two surface-localized electron levels. We find the lifetimes by computing the transition dipole moments on the basis of the numeric calculations of the three-dimensional electron wave functions of a charged fullerene by making use of the density functional theory method implemented in the QuantumEspresso package. We show that the lifetime of a volume-localized level is of order of 1 μs for a transition energy of about 5 eV. This suggests to consider the possibility of using charged fullerenes for generating short-wavelength radiation, including coherent radiation in this range.

MOF-derived hollow Co4S3/C nanosheet arrays grown on carbon cloth as the anode for high-performance Li-ion batteries

2020 ◽  
Vol 49 (40) ◽  
pp. 14115-14122
Author(s):  
Mingchen Shi ◽  
Qiang Wang ◽  
Junwei Hao ◽  
Huihua Min ◽  
Hairui You ◽  
...  
Keyword(s):  
Anode Materials ◽  
High Performance ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Cobalt Sulfide ◽  
Carbon Cloth ◽  
Li Ion Batteries ◽  
High Specific Capacity ◽  
Nanosheet Arrays ◽  
Li Ion

Cobalt sulfide (Co4S3) is considered as one of the most promising anode materials for lithium-ion batteries owing to its high specific capacity.

FACILE SOL–GEL SYNTHESIS OF Li[Li0.2Mn0.56Ni0.16Co0.08]O2 AS IMPROVED CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

2013 ◽  
Vol 01 (04) ◽  
pp. 1340015
Author(s):  
WENJUAN HAO ◽  
HAN CHEN ◽  
YANHONG WANG ◽  
HANHUI ZHAN ◽  
QIANGQIANG TAN ◽  
...  
Keyword(s):  
Cathode Materials ◽  
Sol Gel ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Electrochemical Performances ◽  
Acetate Tetrahydrate ◽  
Li Ion Batteries ◽  
Gel Method ◽  
Sol Gel Method ◽  
Li Ion

Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 cathode materials for Li -ion batteries were synthesized by a facile sol–gel method followed by calcination at various temperatures (700°C, 800°C and 900°C). Lithium acetate dihydrate, manganese (II) acetate tetrahydrate, nickel (II) acetate tetrahydrate and cobalt (II) acetate tetrahydrate are employed as the metal precursors, and citric acid monohydrate as the chelating agent. For the obtained Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 materials, the metal components existed in the form of Mn 4+, Ni 2+ and Co 3+, and their molar ratio was in good agreement with 0.56 : 0.16 : 0.08. The calcination temperature played an important role in the particle size, crystallinity and further electrochemical properties of the cathode materials. The Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 material calcined at 800°C for 6 h showed the best electrochemical performances. Its discharge specific capacities cycled at 0.1 C, 0.5 C, 1 C and 2 C rates were 266.0 mAh g−1, 243.1 mAh g−1, 218.2 mAh g−1 and 192.9 mAh g−1, respectively. When recovered to 0.1 C rate, the discharge specific capacity was 260.2 mAh g−1 and the capacity loss is only 2.2%. This work demonstrates that the sol–gel method is a facile route to prepare high performance Li [ Li 0.2 Mn 0.56 Ni 0.16 Co 0.08] O 2 cathode materials for Li -ion batteries.

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.

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