Understanding the interactions between lithium polysulfides and N-doped graphene using density functional theory calculations

Yin, Li; Liang, Ji; Zhou, Guohui; Li, Feng; Saito, Riichiro; Cheng, Hui‐Ming

doi:10.1016/j.nanoen.2016.04.053

Cited by 363 publications

(211 citation statements)

References 73 publications

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“…67 To investigate the affinitive interaction between pyrrolic N site and lithium polysuldes, ab initio calculation was performed based on density functional theory (DFT). Three soluble polysuldes were used in the simulation (Li 2 S x , x ¼ 3, 4, 8), and they formed ring-like conguration with two Li + ions distributed on each side of the ring aer optimization (Fig.…”

Section: 61mentioning

confidence: 99%

Facile synthesis of mesoporous graphene platelets with in situ nitrogen and sulfur doping for lithium–sulfur batteries

et al. 2017

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The interaction between lithium polysulfides and doped heteroatoms could prevent the loss of soluble polysulfides in the cathode and mitigate the shuttle effect in lithium-sulfur batteries. Herein, a facile synthesis of mesoporous graphene platelets (NSGs) with in situ nitrogen and sulfur doping by the pyrolysis of a self-assembled L-cysteine precursor on sodium chloride crystal surface for structuredirecting is presented. The mesoporous lamellar structure of the NSG possesses a uniform distribution of pyrrolic N, pyridinic N, and thiosulphate structured heteroatoms originating from in situ doping, which promotes the confinement of intermediate polysulfides. Combining the strong interactions with soluble polysulfide, flexible mesoporous architecture, and high conductivity of graphene, the prepared NSG material exhibited a high initial capacity of 1433 mA h g À1 at a 2C rate as well as a reversible capacity of 684 mA h g À1 after 200 cycles. This demonstrates that the in situ nitrogen and sulfur doped thin lamellar structure of graphene would be a promising cathode material for high performance lithium-sulfur batteries.

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Section: 61mentioning

confidence: 99%

Facile synthesis of mesoporous graphene platelets with in situ nitrogen and sulfur doping for lithium–sulfur batteries

et al. 2017

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“…Thec hemical shift of Li 2 S 8 -G is around 0.0 ppm, similar to that of pure Li 2 S 8 solution with the presence of solvents and co-salts. [10] Nevertheless,i ti sn oticed that the broad peak is obviously asymmetric and there is as mall but unignorable split. )a re induced to the carbon lattice at different topological sites (e.g., zigzag edge,a rmchair edge,k ink, and defect), resulting in al arge variety in the local environment surrounding Li.…”

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confidence: 99%

Lithium Bond Chemistry in Lithium–Sulfur Batteries

et al. 2017

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The lithium-sulfur (Li-S) battery is a promising high-energy-density storage system. The strong anchoring of intermediates is widely accepted to retard the shuttle of polysulfides in a working battery. However, the understanding of the intrinsic chemistry is still deficient. Inspired by the concept of hydrogen bond, herein we focus on the Li bond chemistry in Li-S batteries through sophisticated quantum chemical calculations, in combination with Li nuclear magnetic resonance (NMR) spectroscopy. Identified as Li bond, the strong dipole-dipole interaction between Li polysulfides and Li-S cathode materials originates from the electron-rich donors (e.g., pyridinic nitrogen (pN)), and is enhanced by the inductive and conjugative effect of scaffold materials with π-electrons (e.g., graphene). The chemical shift of Li polysulfides in Li NMR spectroscopy, being both theoretically predicted and experimentally verified, is suggested to serve as a quantitative descriptor of Li bond strength. These theoretical insights were further proved by actual electrochemical tests. This work highlights the importance of Li bond chemistry in Li-S cell and provides a deep comprehension, which is helpful to the cathode materials rational design and practical applications of Li-S batteries.

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“…Interestingly, the calculated D Li+ values increased from 8.0 × 10 −8 (C1), 3.0 × 10 −8 (C2), and 6.8 × 10 −8 cm 2 s −1 (A) for the routine PE separator to 1.6 × 10 −7 (C1), 3.2 × 10 −8 (C2), and 7.6 × 10 −8 (A) for the KB/PE membrane, and 2.7 × 10 −7 (C1), 4.2 × 10 −8 (C2), and 1.4 × 10 −7 cm 2 s −1 (A) for the KB‐TPS/PE separator, which is consistent with the measured Li + conductance results (Figure 2B). This improvement in the Li + diffusion coefficient of the modified separator was also proofed by the EIS technique . The details were given in the Figure S7.…”

Section: Resultsmentioning

confidence: 54%

Improve redox activity and cycling stability of the lithium‐sulfur batteries via in situ formation of a sponge‐like separator modification layer

Pang

Xiao

et al. 2020

Int J Energy Res

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Summary The electronic nonconductivity of S and shuttle effect of soluble polysulfides are two fundamental issues that limit the application of lithium‐sulfur (Li‐S) batteries. Regarding these issues, herein, a sponge‐like Ketjen black (KB)‐triphenylphosphine sulfide (TPS) multifunctional modification layer was proposed to coat the separator of the advanced Li‐S batteries. The layer was formed by an in situ spontaneous reaction between triphenylphosphine (TPP) of the conventional KB‐TPP layer and Li2S6 solution. This functional layer can ensure a high e− and Li+ conductivity while inhibiting the diffusion of soluble polysulfides. As a result, the redox activity, rate capability, and cycling stability of the batteries are significantly enhanced. Comparing with the discharge capacities at 2C for the PE separator, introducing the KB‐TPS functional layer was beneficial for the capacity retentions of the cells, since the capacity increased from 16.1% to 66.6% at the same C‐rate. A capacity degeneration rate of 0.045% per cycle was obtained for the cell with an S area density of 3.6 mg cm−2. This work is a step forward in the exploration of advanced Li‐S batteries, being a valuable reference for the study of related systems.

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Understanding the interactions between lithium polysulfides and N-doped graphene using density functional theory calculations

Cited by 363 publications

References 73 publications

Facile synthesis of mesoporous graphene platelets with in situ nitrogen and sulfur doping for lithium–sulfur batteries

Facile synthesis of mesoporous graphene platelets with in situ nitrogen and sulfur doping for lithium–sulfur batteries

Lithium Bond Chemistry in Lithium–Sulfur Batteries

Improve redox activity and cycling stability of the lithium‐sulfur batteries via in situ formation of a sponge‐like separator modification layer

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