Mechanism of polysulfide immobilization on defective graphene sheets with N-substitution

Rao, Dewei; Wang, Yunhui; Zhang, Lingyan; Yao, Shanshan; Qian, Xinye; Xi, Xiaoming; Xiao, Kesong; Deng, Kaiming; Shen, Xiangqian; Lu, Ruifeng

doi:10.1016/j.carbon.2016.09.021

Cited by 99 publications

(46 citation statements)

References 56 publications

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“…Furthermore, with the decreasing number of S atoms in polysulfides, the Li-S bond lengths of these Li 2 S n species shorten, while the distances between two S atoms increase, indicating that long-chain Li 2 S n species are more easily ionized into Li cation and polysulfide anion in the electrolytes than short-chain Li 2 S 2 or Li 2 S, which are consistent with previous simulation works. [68][69][70][71] The optimized structures of As, Sb and Bi monolayers are displayed in Figure 1B. These 2D materials with buckled structures contain 32 As/Sb/ Bi atoms and each atom is covalently bonded to three neighboring atoms.…”

Section: Methodsmentioning

confidence: 99%

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

Mao

Zhu

2021

Int J of Quantum Chemistry

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Finding effective anchoring materials for the immobilization of soluble lithium polysulfides to suppress the shuttling effect has become the key to large-scale application of lithium-sulfur (Li-S) batteries. In this work, the potentials of group-VA twodimensional (2D) materials including arsenene, antimonene and bismuthene (As, Sb and Bi monolayers) as Li-S battery cathode anchoring materials were systematically investigated by density functional theory (DFT) calculations. The adsorption energies of sulfur (S 8 ) and various lithium polysulfides (Li 2 S n , n = 8, 6, 4, 2, 1), as well as the diffusion energy barriers for long-chain Li 2 S 4 and Li 2 S 6 on these three monolayers were studied in detail. The calculated moderate adsorption energies of these monolayers to all polysulfides imply that they can effectively inhibit the shuttling effect. The favorable diffusion barriers for Li 2 S 4 and Li 2 S 6 ensure the efficient diffusion of polysulfides on monolayer surface. In addition, these 2D materials can keep a balance between binding strength and the structural integrity of polysulfides. The presented merits demonstrate that As, Sb and Bi monolayers can be the promising cathode anchoring materials to improve performance of Li-S batteries.

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Section: Methodsmentioning

confidence: 99%

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

Mao

Zhu

2021

Int J of Quantum Chemistry

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“…These results suggest that LiPSs prefer to be adsorbed on MoN rather than on graphene. Furthermore, the adsorption is achieved by forming Mo‐S bonds, which can be reasonably considered to avoid the overhead of polysulfide cation escape resulting from the ionization of LiPSs in the electrolyte …”

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confidence: 99%

MoN Supported on Graphene as a Bifunctional Interlayer for Advanced Li‐S Batteries

Tian

Song

Wang

et al. 2019

Advanced Energy Materials

201

148

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drastically superior specific energy density. [1][2][3][4][5][6][7] However, the successful implementation of Li-S batteries is still hindered by many challenges. One of the largest problems facing the current Li-S battery is the rapid capacity decay and serious selfdischarge caused by the dissolution and migration of intermediate lithium polysulfides (LiPSs). [8][9][10][11][12][13][14][15] Significant efforts have been dedicated to the research of suitable approach to address polysulfide shuttling. As one of the strategies, inserting an interlayer between the separator and sulfur electrode is widely applied due to the minimal changes to existing applications. [16][17][18][19] Various materials such as metal oxides, sulfides, and metal-organic frameworks have been proposed as functional interlayer to trap LiPSs through chemisorption, and this strategy has been demonstrated to be effective to block the migration of polysulfide species. [20][21][22][23][24] The interlayer serves as both adsorbent and current collector, where polysulfides can be reduced to insoluble products. [25,26] While this helps block LiPSs and improve the sulfur utilization, the produced Li 2 S is hard to oxidize back to soluble LiPSs due to the intrinsically poor electrical and ionic conductivity. [27] The accumulation of Li 2 S not only leads to the loss of active materials but also passivates the interlayer and impairs the electrochemical performance because of the insufficient transport of Li ions especially for cathodes with high sulfur loading. [1,16,[27][28][29] There is thereby an urgent need but it is still a significant challenge to develop interlayers that can not only block LiPSs but also accelerate Li 2 S oxidation on interlayers.To achieve this, we propose several key factors to consider when developing a practical bifunctional interlayer: 1) the adsorption energies between interlayer and LiPSs/Li 2 S that provides a strong anchoring; 2) the Li ion diffusion barrier that ensures good Li ion mobility; 3) the electrical conductivity of interlayer materials that facilitates electron transport and electrochemical conversions. In this work, we introduce MoN as a suitable interlayer material for Li-S batteries. On the one hand, the surface Mo atoms with unoccupied orbitals act as Lewis acid sites, and thus, MoN can serve as a good adsorbent for LiPSs. [30,31] On the other hand, our theoretical calculation reveals an extremely low Li ion diffusion barrier on MoN Rational design of effective polysulfide barriers is highly important for highperformance lithium-sulfur (Li-S) batteries. A variety of adsorbents have been applied as interlayers to alleviate the shuttle effect. Nevertheless, the unsuccessful oxidation of Li 2 S on interlayers leads to loss of active materials and blocks Li ion transport. In this work, a MoN-based interlayer sandwiched between the C-S cathode and the separator is developed. Such an interlayer not only strongly binds lithium polysulfides via Mo-S bonding but also efficiently accelerates the decomposition of Li 2...

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“…43 And we used the vdW-DF2 functional to include the physical van der Waals (vdW) interaction in the simulation 44 , which is proved to be very important for calculation. 45,46 A 4 × 4 × 1 Monkhorst-Pack k grid was used for sampling the Brillouin zones at structure calculation, whereas a denser mesh of 8× 8× 1 used to calculate the densities of the states (DOS), which is to use to insure our calculation accuracy. All the atomic positions and lattice vectors fully optimized using a conjugate gradient algorithm to obtain the unstrained conFigureuration.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Simultaneous Immobilization and Conversion of Polysulfides on Co₃O₄–CoN Heterostructured Mediators toward High-Performance Lithium–Sulfur Batteries

Wang

Xiao

Ouyang

et al. 2019

ACS Appl. Energy Mater.

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Lithium−sulfur batteries exhibit great promise as a next-generation rechargeable battery system due to their high energy density, natural abundance and nontoxicity. Nevertheless, the insulated property of sulfur and lithium sulfides, and the electrochemical instability of intermediate polysulfides obstruct the commercialization of Li-S technologies. Herein, a hetero-phase Co3O4-CoN sulfur host with the merits of efficient polysulfide anchoring (Co3O4) and high conductivity (CoN) is reported to enhance Li-S battery performance. Such porous Co3O4-CoN heterostructures endow the intermediated lithium polysulfides with highly-efficient immobilization-diffusionconversion process, thus enabling the accelerated redox kinetics and alleviating the polysulfide shuttling. The assembled cathode based on Co3O4-CoN/CC electrode exhibits a high initial capacity of 1225 mAh g -1 at 0.5C with excellent rate capability (887 mAh g -1 at 3C), and the specific capacity can be well-maintained to 627 mAh g -1 at 3C even after 500 cycles. Our work provides an in-depth insight into the rational design of comprehensive host materials which realizes synchronous LiPS adsorption and conversion, and will greatly promote the practical use of Li-S batteries.

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Mechanism of polysulfide immobilization on defective graphene sheets with N-substitution

Cited by 99 publications

References 56 publications

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

MoN Supported on Graphene as a Bifunctional Interlayer for Advanced Li‐S Batteries

Simultaneous Immobilization and Conversion of Polysulfides on Co₃O₄–CoN Heterostructured Mediators toward High-Performance Lithium–Sulfur Batteries

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Mechanism of polysulfide immobilization on defective graphene sheets with N-substitution

Cited by 99 publications

References 56 publications

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

Arsenene, antimonene and bismuthene as anchoring materials for lithium‐sulfur batteries: A computational study

MoN Supported on Graphene as a Bifunctional Interlayer for Advanced Li‐S Batteries

Simultaneous Immobilization and Conversion of Polysulfides on Co3O4–CoN Heterostructured Mediators toward High-Performance Lithium–Sulfur Batteries

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Simultaneous Immobilization and Conversion of Polysulfides on Co₃O₄–CoN Heterostructured Mediators toward High-Performance Lithium–Sulfur Batteries