Molecular Spectroscopy by Means of ESCA II. Sulfur compounds. Correlation of electron binding energy with structure

Lindberg, B.; Hamrin, K.; Johansson, G.; Gelius, U.; Fahlman, Anders; Nordling, C.; Siegbahn, Kai

doi:10.1088/0031-8949/1/5-6/020

Cited by 794 publications

(421 citation statements)

References 46 publications

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“…The new significant contribution between 171 and 165 eV can be fit with two sulfur environments. The S2p 3/2 peak at 167.2 eV is in precise accord with the binding energy of thiosulfate 42 Fig. 5a).…”

Section: Resultssupporting

confidence: 73%

A highly efficient polysulfide mediator for lithium–sulfur batteries

et al. 2015

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The lithium-sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here we report a strategy to entrap polysulfides in the cathode that relies on a chemical process, whereby a hostmanganese dioxide nanosheets serve as the prototype-reacts with initially formed lithium polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind 'higher' polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75 wt% sulfur exhibits a reversible capacity of 1,300 mA h g À 1 at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.

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Section: Resultssupporting

confidence: 73%

A highly efficient polysulfide mediator for lithium–sulfur batteries

et al. 2015

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“…This was the only type of sulfur atom that would be present in Li 2 S 2 , while all higher-order linear polysulfides would have two of these sulfurs at the termini of their polysulfide chains, regardless of chain length. The shift to higher binding energy was consistent with the intermediate anionic character of these atoms, 33,34 with theoretical studies putting the effective charge of terminal sulfur atoms between −0.90 (in Li 2 S 3 ) and −0.77 (in Li 2 S 6 ). 35 From the theoretical trend, the charge on terminal sulfur atoms in Li 2 S 2 can be assumed to be more negative than −0.90, though still significantly more covalent than in Li 2 S.…”

Section: Resultssupporting

confidence: 74%

Elucidating the Electrochemical Activity of Electrolyte-Insoluble Polysulfide Species in Lithium-Sulfur Batteries

Klein

Goossens

Bielawski

et al. 2016

J. Electrochem. Soc.

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The direct synthesis of Li 2 S 2 , a proposed solid intermediate in the discharge of lithium-sulfur (Li-S) batteries, was accomplished by treating elemental lithium with sulfur in liquid ammonia at −41 • C. The as-synthesized product was analyzed by X-ray photoelectron spectroscopy (XPS) as well as X-ray diffraction (XRD) and determined to be a mixture of crystalline Li 2 S, amorphous Li 2 S 2, and higher-order polysulfides (Li 2 S x , x > 2). Monitored filtration followed by a tailored electrochemical approach was used to successfully remove the higher-order polysulfides and yielded a powder, which was determined by XPS to be comprised of ∼9 mol% insoluble polysulfide species (mainly Li 2 S 2 ) and ∼91 mol% Li 2 S. This material was discharged galvanostatically in an electrochemical cell and, despite the lack of soluble polysulfide species, was shown to exhibit a discharge plateau at ∼2.1 V vs. Li/Li + . This result confirmed the electrochemical reducibility of electrolyte-insoluble polysulfides in Li-S batteries. Moreover, it was determined that the reduction of solid polysulfides was confined to areas where the sulfur-sulfur bonds were in intimate contact with the conductive current collector. Finally, it was observed that commercially available Li 2 S samples contain significant quantities of polysulfide-type impurities. Lithium-sulfur (Li-S) batteries have emerged in recent years as promising next-generation energy storage devices to meet the growing need for affordable, highly energy-dense systems for electrical vehicles and grid-scale applications.1,2 The high theoretical gravimetric energy density (1672 mAh g −1 ) of the Li-S system coupled with the low-cost and abundance of sulfur offers significant advantages over current lithium-ion batteries.2 However, the conversion nature of the Li-S system leads to a complicated charge/discharge mechanism that passes through multiple soluble and insoluble species on each halfcycle. 2,3 This opens up a multitude of mechanisms for active material loss during long-term cycling. Additionally, the insulating nature of sulfur and lithium sulfide, the final discharge product, limits the rate capability of the system and necessitates forming composite cathodes with a conductive material such as carbon. 1,2Of particular concern to the loss of capacity with cycling is the deposition of electrochemically-inaccessible solid sulfide species (Li 2 S x , x < 3).4,5 Multiple literature reports have reached different conclusions on the existence of the solid, electrolyte-insoluble species Li 2 S 2 and whether it forms as a solid intermediate during the discharge of Li-S batteries. [5][6][7][8][9][10][11][12] Recent studies have suggested there may be separate reaction pathways that are followed at different points during Li-S discharge: one where only Li 2 S is formed during reduction of soluble polysulfides (Li 2 S x , x > 2), and a second where both Li 2 S and Li 2 S 2 are formed simultaneously. 11 The question of whether any Li 2 S 2 that forms can then be reduced is debated in...

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“…peaks corresponding to metal sulfides. 26 In comparing the two sulfur-containing UTSF and UTSP samples, we observed that UTSF contained approximately 9 times more total surface sulfur (7.4% vs 0.8%) and 16 times more reduced sulfur (6.7% vs 0.4%) than UTSP when normalized to carbon. The greater fraction of reduced sulfur groups on the UTSF sample could possibly contribute to its effectiveness as a Hg capture sorbent.…”

Section: ■ Results and Discussionmentioning

confidence: 81%

An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

Saha

Abram

Kuhl

et al. 2013

Environ. Sci. Technol.

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This work explores surface changes and the Hg capture performance of brominated activated carbon (AC) pellets, sulfur-treated AC pellets, and sulfur-treated AC fibers upon exposure to simulated Powder River Basin-fired flue gas. Hg breakthrough curves yielded specific Hg capture amounts by means of the breakthrough shapes and times for the three samples. The brominated AC pellets showed a sharp breakthrough after 170−180 h and a capacity of 585 μg of Hg/g, the sulfur-treated AC pellets exhibited a gradual breakthrough after 80−90 h and a capacity of 661 μg of Hg/g, and the sulfur-treated AC fibers showed no breakthrough even after 1400 h, exhibiting a capacity of >9700 μg of Hg/g. X-ray photoelectron spectroscopy was used to analyze sorbent surfaces before and after testing to show important changes in quantification and oxidation states of surface Br, N, and S after exposure to the simulated flue gas. For the brominated and sulfur-treated AC pellet samples, the amount of surface-bound Br and reduced sulfur groups decreased upon Hg capture testing, while the level of weaker Hg-binding surface S(VI) and N species (perhaps as NH 4 + ) increased significantly. A high initial concentration of strong Hg-binding reduced sulfur groups on the surface of the sulfur-treated AC fiber is likely responsible for this sorbent's minimal accumulation of S(VI) species during exposure to the simulated flue gas and is linked to its superior Hg capture performance compared to that of the brominated and sulfur-treated AC pellet samples.

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Molecular Spectroscopy by Means of ESCA II. Sulfur compounds. Correlation of electron binding energy with structure

Cited by 794 publications

References 46 publications

A highly efficient polysulfide mediator for lithium–sulfur batteries

A highly efficient polysulfide mediator for lithium–sulfur batteries

Elucidating the Electrochemical Activity of Electrolyte-Insoluble Polysulfide Species in Lithium-Sulfur Batteries

An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

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