Theoretical study of SnS2 encapsulated in Graphene as a promising anode material for K−ion batteries

Author(s):  
Xuxin Kang ◽  
Wei Xu ◽  
Xiangmei Duan

Abstract Rechargeable batteries with superior electronic conductivity, large capacity, low diffusion barriers and moderate open circuit voltage have attracted amount attention. Due to abundant resources and safety, as well as the high voltage and energy density, potassium ion batteries (KIBs) could be an ideal alternative to next−generation of rechargeable batteries. Based on the density functional theory calculations, we find that the SnS2 monolayer expands greatly during the potassiumization, which limits its practical application. The construction of graphene/SnS2/graphene (G/SnS2/G) heterojunction effectively prevents SnS2 sheet from deformation, and enhances the electronic conductivity. Moreover, the G/SnS2/G has not only a high theoretical special capacity of 680 mAh/g, but an ultra−low K diffusion barrier (0.08 eV) and an average open circuit voltage (0.22 V). Our results predict that the G/SnS2/G heterostructure could be used as a promising anode material for KIBs.

2021 ◽  
Vol 58 (6) ◽  
pp. 13-23
Author(s):  
D. Sergeyev ◽  
N. Zhanturina ◽  
A. Aizharikov ◽  
A.I. Popov

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 %.


2016 ◽  
Vol 4 (29) ◽  
pp. 11498-11506 ◽  
Author(s):  
Taehun Lee ◽  
Yonghyuk Lee ◽  
Woosun Jang ◽  
Aloysius Soon

Using first-principles density-functional theory calculations, we investigate the advantage of using h-WO3 (and its surfaces) over the larger band gap γ-WO3 phase for the anode in water splitting. We demonstrate that h-WO3 is a good alternative anode material for optimal water splitting efficiencies.


Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 58
Author(s):  
Anastasia A. Shakirova ◽  
Felix N. Tomilin ◽  
Vladimir A. Pomogaev ◽  
Natalia G. Vnukova ◽  
Grigory N. Churilov ◽  
...  

Gd endohedral complexes of C82 fullerenols were synthesized and mass spectrometry analysis of their composition was carried out. It was established that the synthesis yields a series of fullerenols Gd@C82Ox(OH)y (x = 0, 3; y = 8, 16, 24, 36, 44). The atomic and electronic structure and properties of the synthesized fullerenols were investigated using the density functional theory calculations. It was shown that the presence of endohedral gadolinium increases the reactivity of fullerenols. It is proposed that the high-spin endohedral fullerenols are promising candidates for application in magnetic resonance imaging.


Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 430
Author(s):  
Lukas Kyvala ◽  
Maxim Tchaplianka ◽  
Alexander Shick ◽  
Sergii Khmelevskyi ◽  
Dominik Legut

We theoretically investigate the electronic and magnetic structure of Fe 2 Hf. The density functional theory calculations are shown to produce the negative, easy-plane, magnetic anisotropy in the hexagonal Fe 2 Hf. Antimony substitution suppresses the planar magnetization direction and favors the uniaxial magnetic anisotropy, in agreement with experimental observations. Our study suggests the possibility of the chemical control of the magnetic anisotropy in Fe 2 Hf by Sb substitution, and illustrates the potential of (Fe,Sb) 2 + x Hf 1 − x Laves phase alloys for the permanent magnet applications.


Author(s):  
M. Mirnezhad ◽  
R. Ansari ◽  
H. Rouhi ◽  
M. Faghihnasiri

The application of graphene as a nanosensor in measuring strain through its band structure around the Fermi level is investigated in this paper. The mechanical properties of graphene as well as its electronic structure are determined by using the density functional theory calculations within the framework of generalized gradient approximation. In the case of electronic properties, the simulations are applied for symmetrical and asymmetrical strain distributions in elastic range; also the tight-binding approach is implemented to verify the results. It is indicated that the energy band gap does not change with the symmetrical strain distribution but depend on the asymmetric strain distribution, increasing strain leads to band gap opening around the Fermi level.


2018 ◽  
Vol 34 (5) ◽  
pp. 2292-2304
Author(s):  
S. Dheivamalar ◽  
K. Bansura banu

In this study, the electronic and structural properties of drum structured Mo-doped Zn6O6 (MoZn5O6) cluster as the π conjugated bridging in the dye-sensitized solar cells (DSSC) were compared with its pristine form by density functional theory (DFT) calculations under Gaussian 09 Program. The frontier molecular orbital study was explored to determine the charge transport characteristics of donor-acceptor moieties over the entire visible range and the electron injection from the valence band (LUMO) orbital to the conduction band (HOMO) orbital of MoZn5O6. The energy gap (Eg), binding energy (EB), global reactivity descriptors, thermodynamic parameters and the dipole moment were also calculated for MoZn5O6 and compared with Zn6O6. The density of states (DOS) of MoZn5O6 material was investigated to demonstrate the importance of d orbital of Mo atom in hybridization. To examine the charge distribution, Mulliken atomic charge distribution and molecular electrostatic potential (MEP) were analyzed. A spectroscopic study was included for the better perception of the interaction of Mo with Zn6O6 cluster. The increased value of the first-order hyperpolarizability of MoZn5O6 from its pure clustermanifests the MoZn5O6 is a better candidate with the superior nonlinear optical property. The analysis of UV-Vis spectra through the time-dependent density functional theory (TD-DFT) discovers that the MoZn5O6 has larger light harvesting efficiency (LHE) which influences the higher photon to current conversion efficiency. As a result, the valence band (LUMO) of MoZn5O6 is intense than the conduction band (HOMO) of MoZn5O6 making an increase in the open circuit voltage (VOC) and hence it confirms that the MoZn5O6 material can be a used in photovoltaic applications.


2016 ◽  
Vol 40 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Zhenfeng Zhang ◽  
Nana Ma ◽  
Xiaopeng Xuan

An unusual CC⋯CO interaction has been discovered in (Z)-3-[(4-halogenphenyl)amino]-2-cyanoprop-2-enoates and rationalized by the density functional theory calculations.


2011 ◽  
Vol 233-235 ◽  
pp. 491-494 ◽  
Author(s):  
Lin Yu ◽  
Yue Liu ◽  
Zhi Gang Wei ◽  
Gui Qiang Diao ◽  
Ming Sun ◽  
...  

There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO2 to adsorb the arsenic. As the TiO2 surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO2 anatase (1 0 1) surface. All the arsenic(III) solution species such as H3AsO3, H2AsO3-1, HAsO3-2 and AsO3-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO2 surface.


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