scholarly journals Trapping polysulfide on two-dimensional molybdenum disulfide for Li–S batteries through phase selection with optimized binding

2019 ◽  
Vol 10 ◽  
pp. 774-780 ◽  
Author(s):  
Sha Dong ◽  
Xiaoli Sun ◽  
Zhiguo Wang

Introducing anchoring materials into cathodes for Li–S batteries has been demonstrated as an effective way to overcome the shuttle effect and enhance the cycling stability. In this work, the anchoring effects of 2H-MoS2 and 1T'-MoS2 monolayers for Li–S batteries were investigated by using density functional theory calculations. It was found that the binding energies of Li2S x absorbed on 1T'-MoS2 monolayer are in the range of 0.31–2.94 eV, which is much higher than on the 2H-phase. The 1T'-MoS2 monolayer shows stronger trapping ability for Li2S x than the 2H-MoS2 monolayer. The 1T'-MoS2 monolayer can be used as effective anchoring material in cathodes for Li–S batteries.

2019 ◽  
Author(s):  
Qitang Fan ◽  
Daniel Martin-Jimenez ◽  
Daniel Ebeling ◽  
Claudio K. Krug ◽  
Lea Brechmann ◽  
...  

Various two-dimensional (2D) carbon allotropes with non-alternant topologies, such as pentaheptites and phagraphene, have been proposed. Predictions indicate that these metastable carbon polymorphs, which contain odd-numbered rings, possess unusual (opto)electronic properties. However, none of these materials has been achieved experimentally due to synthetic challenges. In this work, by using on-surface synthesis, nanoribbons of the non-alternant graphene allotropes, phagraphene and tetra-penta-hepta(TPH)-graphene have been obtained by dehydrogenative C-C coupling of 2,6-polyazulene chains. These chains were formed in a preceding reaction step via on-surface Ullmann coupling of 2,6-dibromoazulene. Low-temperature scanning probe microscopies with CO-functionalized tip and density functional theory calculations have been used to elucidate their structural properties. <br>


Author(s):  
Zhen Feng ◽  
Zelin Yang ◽  
Xiaowen Meng ◽  
Fachuang Li ◽  
Zhanyong Guo ◽  
...  

The development of single-atom catalysts (SACs) for electrocatalytic nitrogen reduction reaction (NRR) remains a great challenge. Using density functional theory calculations, we design a new family of two-dimensional metal-organic frameworks...


2019 ◽  
Vol 21 (43) ◽  
pp. 24206-24211
Author(s):  
Seoung-Hun Kang ◽  
Jejune Park ◽  
Sungjong Woo ◽  
Young-Kyun Kwon

Using ab initio density functional theory calculations, we find four-fold degenerate Dirac points protected by two nonsymmorphic symmetries in phosphorene oxide with the inversion symmetry broken.


Nanoscale ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 3780-3785 ◽  
Author(s):  
Ik Seon Kwon ◽  
In Hye Kwak ◽  
Hafiz Ghulam Abbas ◽  
Hee Won Seo ◽  
Jaemin Seo ◽  
...  

Mn-Porphyrin-MoS2 exhibits excellent electrocatalytic activity toward the hydrogen evolution reaction, which is supported by spin-polarized density functional theory calculations.


Author(s):  
Quintin Hill ◽  
Chris-Kriton Skylaris

While density functional theory (DFT) allows accurate quantum mechanical simulations from first principles in molecules and solids, commonly used exchange-correlation density functionals provide a very incomplete description of dispersion interactions. One way to include such interactions is to augment the DFT energy expression by damped London energy expressions. Several variants of this have been developed for this task, which we discuss and compare in this paper. We have implemented these schemes in the ONETEP program, which is capable of DFT calculations with computational cost that increases linearly with the number of atoms. We have optimized all the parameters involved in our implementation of the dispersion correction, with the aim of simulating biomolecular systems. Our tests show that in cases where dispersion interactions are important this approach produces binding energies and molecular structures of a quality comparable with high-level wavefunction-based approaches.


2021 ◽  
Author(s):  
Thomas Joseph ◽  
Mahdi Ghorbani-Asl ◽  
Matthias Batzill ◽  
Arkady V Krasheninnikov

The adsorption and dissociation of water molecules on two-dimensional transition metal dichalco- genides (TMDs) is expected to be dominated by point defects, such as vacancies, and edges. At the same...


2019 ◽  
Author(s):  
Qitang Fan ◽  
Daniel Martin-Jimenez ◽  
Daniel Ebeling ◽  
Claudio K. Krug ◽  
Lea Brechmann ◽  
...  

Various two-dimensional (2D) carbon allotropes with non-alternant topologies, such as pentaheptites and phagraphene, have been proposed. Predictions indicate that these metastable carbon polymorphs, which contain odd-numbered rings, possess unusual (opto)electronic properties. However, none of these materials has been achieved experimentally due to synthetic challenges. In this work, by using on-surface synthesis, nanoribbons of the non-alternant graphene allotropes, phagraphene and tetra-penta-hepta(TPH)-graphene have been obtained by dehydrogenative C-C coupling of 2,6-polyazulene chains. These chains were formed in a preceding reaction step via on-surface Ullmann coupling of 2,6-dibromoazulene. Low-temperature scanning probe microscopies with CO-functionalized tip and density functional theory calculations have been used to elucidate their structural properties. <br>


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