DFT study of chemical reactivity parameters of lithium polysulfide molecules Li2Sn<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mn>1</mml:mn><mml:mo>≤</mml:mo><mml:mi mathvariant="normal">n</mml:mi><mml:mo>≤</mml:mo><mml:mn>8</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> in gas and solvent phase

Cheviri, Meera; Lakshmipathi, Senthilkumar

doi:10.1016/j.comptc.2021.113323

Cited by 15 publications

(11 citation statements)

References 62 publications

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“…We estimated the work function for S 8 /Na 2 S n species using the equation ϕ = V vac – E F , where V vac and E F are the vacuum potential and the Fermi energy of the specific system, respectively. The work function for the short-chain polysulfides ( n = 1 and 2) is lower than that for the soluble long-chain polysulfides ( n = 4 to 8) (Figure S2), which indicates that lower-order polysulfides are less reactive …”

Section: Resultsmentioning

confidence: 93%

“…The work function for the shortchain polysulfides (n = 1 and 2) is lower than that for the soluble long-chain polysulfides (n = 4 to 8) (Figure S2), which indicates that lower-order polysulfides are less reactive. 56 First, we relaxed the Na 2 S n species and then placed them on the surface of AMs at different available lattice sites (see Figure S3). For further calculations, we only considered the structures with the lowest energies, and the anchoring behavior was investigated in terms of binding energy, which was calculated using the following equation.…”

Section: Calculation Methodologymentioning

confidence: 99%

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Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Nahian

Jayan

Kaewmaraya

et al. 2022

ACS Appl. Mater. Interfaces

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Multiple unfavorable features, such as poor electronic conductivity of sulfur cathodes, the dissolution and shuttling of sodium polysulfides (Na 2 S n ) in electrolytes, and the slower kinetics for the decomposition of solid Na 2 S, make sodium−sulfur batteries (NaSBs) impractical. To overcome these obstacles, novel double-transition metal (DTM) MXenes, Mo 2 TiC 2 T 2 , (T = O and S) are studied as an anchoring material (AM) to immobilize higher-order polysulfides and to expedite the otherwise slower kinetics of insoluble short-chain polysulfides. Density functional theory (DFT) calculations are carried out to justify and compare the effectiveness of Mo 2 TiC 2 S 2 and Mo 2 TiC 2 O 2 as AMs by analyzing their interactions with S 8 /Na 2 S n (n = 1, 2, 4, 6, and 8). Mo 2 TiC 2 S 2 provides moderate adsorption strength compared to Mo 2 TiC 2 O 2 , therefore, it is expected to effectively inhibit Na 2 S n dissolution and shuttling without causing decomposition of Na 2 S n . The calculated Gibbs free energies of the rate-determining step for sulfur reduction reactions (SRR) are found to be significantly lower (0.791 eV for S and 0.628 eV for O functionalization) than that in vacuum (1.442 eV), suggesting that the SRR is more thermodynamically favorable on Mo 2 TiC 2 T 2 during discharge. Additionally, both Mo 2 TiC 2 S 2 and Mo 2 TiC 2 O 2 demonstrated effective electrocatalytic activity for the decomposition of Na 2 S, with a substantial reduction in the energy barrier to 1.59 eV for Mo 2 TiC 2 S 2 and 1.67 eV for Mo 2 TiC 2 O 2 . While Mo 2 TiC 2 O 2 had superior binding properties, structural distortion is observed in Na 2 S n , which may adversely affect cyclability. On the other hand, because of its moderate binding energy, enhanced electronic conductivity, and significantly faster oxidative decomposition kinetics of polysulfides, Mo 2 TiC 2 S 2 can be considered as an effective AM for suppressing the shuttle effect and improving the performance of NaSBs.

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Section: Resultsmentioning

confidence: 93%

Section: Calculation Methodologymentioning

confidence: 99%

Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Nahian

Jayan

Kaewmaraya

et al. 2022

ACS Appl. Mater. Interfaces

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“…[31] In general, molecules with high polarity are easier to attract or repel valence electrons from other compounds and undergo electron transfer, therefore, the higher the dipole moment, the less stable the molecule. [32][33][34][35] As shown in Figure 6, the dipole moments of TCNQ/FTCNQ/F 4 TCNQ molecules are 0.0031/0.8645/0.0001D, respectively, indicating that FTCNQ electrode materials are more easily dissolved in the electrolyte than TCNQ and F 4 TCNQ electrode materials. The dipole moments of the discharge products (TCNQ-2Zn, FTCNQ-2Zn and F 4 TCNQ-2Zn in AZIBs) are 0.0012D, 0.7965D and 0.0027D, respectively, indicating that the discharge products FTCNQ-2Zn and F 4 TCNQ-2Zn are more unstable than TCNQ-2Zn.…”

Section: Electrochemical Performance Of Tcnq/ftcnq/f 4 Tcnq Electrodesmentioning

confidence: 95%

Effect of Fluoride Atoms on the Electrochemical Performance of Tetracyanoquinodimethane(TCNQ) Electrodes in Zinc‐ion Batteries

et al. 2023

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Tetracyanoquinodimethane (TCNQ) electrode material has achieved excellent performance in aqueous zinc‐ion batteries (AZIBs). However, fundamental understanding about effect of substitutes on electrochemical performance of TCNQ remain unknown. In this work, the effects of fluorine (F) as an electron‐absorbing group on the structure, morphology and electrochemical performance of TCNQ and storage mechanism of TCNQ in AZIBs are discussed. Theoretical calculation proves that the introduction of fluorine atoms decreases lowest unoccupied molecular orbital (LUMO) energy of TCNQ thus affect the redox potential. Electrochemical performance of TCNQ/Fluoro‐7,7,8,8‐tetracyanoquinodimethane (FTCNQ)/2,3,5,6‐Tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) is evaluated from 25 °C to −20 °C in AZIBs. Results tend out that with the increasing substituents of F on TCNQ molecular, their stability in AZIBs decrease. Dipole moment calculation further shows that the introduction of fluorine atoms is inconducive to the stability of the electrode material in aqueous solution. Ex‐situ characterization demonstrate that electron withdrawing groups do not change the REDOX center of TCNQ electrode materials. Our work provides a new thought for the selection of the electrode material in AZIBs.

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“…The Gaussian integration scheme was applied with a smearing width of 0.05 eV. The Li 2 S polysulfide structure was used in our calculations as a model example, based on the structures reported by Cheviri et al , 41 along with its derivatives that are S rich or Li deficient, and various S-bound MXene surfaces were considered. The binding energies of the sulfur atom within the polysulphide and sulphur bound to MXenes were calculated using the surface-defect-physics approach, explained in detail by Freysoldt et al , 42 as a function of sulfur chemical potential.…”

Section: Dft Calculationsmentioning

confidence: 99%

Ti₃C₂T_x nanosheet@Cu/Fe-MOF separators for high-performance lithium–sulfur batteries: an experimental and density functional theory study

Kiai,

Ponnada,

Eroglu

et al. 2024

Dalton Trans.

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DFT study of chemical reactivity parameters of lithium polysulfide molecules Li2Sn(1≤n≤8) in gas and solvent phase

Cited by 15 publications

References 62 publications

Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Effect of Fluoride Atoms on the Electrochemical Performance of Tetracyanoquinodimethane(TCNQ) Electrodes in Zinc‐ion Batteries

Ti₃C₂T_x nanosheet@Cu/Fe-MOF separators for high-performance lithium–sulfur batteries: an experimental and density functional theory study

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DFT study of chemical reactivity parameters of lithium polysulfide molecules Li2Sn(1≤n≤8) in gas and solvent phase

Cited by 15 publications

References 62 publications

Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Elucidating Synergistic Mechanisms of Adsorption and Electrocatalysis of Polysulfides on Double-Transition Metal MXenes for Na–S Batteries

Effect of Fluoride Atoms on the Electrochemical Performance of Tetracyanoquinodimethane(TCNQ) Electrodes in Zinc‐ion Batteries

Ti3C2Tx nanosheet@Cu/Fe-MOF separators for high-performance lithium–sulfur batteries: an experimental and density functional theory study

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Ti₃C₂T_x nanosheet@Cu/Fe-MOF separators for high-performance lithium–sulfur batteries: an experimental and density functional theory study