Sulfur distribution on the surface of mesoporous nanofibrous carbon

Shinkarev, V. V.; Фенелонов, В. Б.; Kuvshinov, G. G.

doi:10.1016/s0008-6223(02)00290-7

Cited by 29 publications

(22 citation statements)

References 16 publications

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“…This indicates that the elemental sulfur is embedded into the micropores of T_BC due to extremely strong physical adsorption [27,29]. And as shown in the inset of Fig.…”

Section: Resultsmentioning

confidence: 82%

Microporous bamboo biochar for lithium-sulfur batteries

et al. 2014

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Being simple, inexpensive, scalable and environmentally friendly, microporous biomass biochars have been attracting enthusiastic attention for application in lithium-sulfur (Li-S) batteries. Herein, porous bamboo biochar is activated via a KOH/annealing process that creates a microporous structure, boosts surface area and enhances electronic conductivity. The treated sample is used to encapsulate sulfur to prepare a microporous bamboo carbon-sulfur (BC-S) nanocomposite for use as the cathode for Li-S batteries for the first time. The BC-S nanocomposite with 50 wt.% sulfur content delivers a high initial capacity of 1,295 mA·h/g at a low discharge rate of 160 mA/g and high capacity retention of 550 mA·h/g after 150 cycles at a high discharge rate of 800 mA/g with excellent coulombic efficiency (≥95%). This suggests that the BC-S nanocomposite could be a promising cathode material for Li-S batteries.

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“…This indicates that the elemental sulfur is embedded into the micropores of T_BC due to extremely strong physical adsorption [27,29]. And as shown in the inset of Fig.…”

Section: Resultsmentioning

confidence: 82%

Microporous bamboo biochar for lithium-sulfur batteries

et al. 2014

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“…The diffraction peak at ≈25.4° for the RGO/S demonstrates that the as‐prepared RGO/S composite has graphite‐like structure but with larger interplanar distance than the pristine graphite. It has been reported that at 600 °C, the 99% of S 8 will be broken into S 2 and these S 2 can strongly interact with the surface of carbon to form a monolayered coverage of the carbon surface . Due to its the high activity, S 2 can reduce the oxygen functional groups and simultaneously intercalate into the interlayers of expanded graphite to form RGO/S intercalated compounds.…”

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confidence: 65%

“…[ 26 ] Because of the large interlayer distance, expanded graphite has been investigated as host to embed S. The expanded graphiteembedded sulfur nanocomposites were normally synthesized by two-step reactions: thermal reduction of graphite oxides in H 2 /Ar at a high temperature (450 °C) and fl owed by S meltdiffusion at a low temperature of ≈155 °C. [ 29,30 ] Due to the large interplanar distance of GO, these S 2 molecules can intercalate into GO to deoxygenate GO and form SO 2 gas. Figure 1 schematically depicts the preparation process of the RGO/S composite.…”

mentioning

confidence: 99%

“…Figure 1 schematically depicts the preparation process of the RGO/S composite. At room temperature, sulfur exists mainly in the form of cyclooctasulfur (S 8 ), as heating the mixture of graphite oxide and S 8 to 600 °C, the large molecule S 8 will be broken into smaller chain species S 2 . Due to the large interplanar distance of GO, these S 2 molecules can intercalate into GO to deoxygenate GO and form SO 2 gas .…”

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confidence: 99%

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In Situ Sulfur Reduction and Intercalation of Graphite Oxides for Li‐S Battery Cathodes

Zheng

Yang

Zhu

et al. 2014

Advanced Energy Materials

124

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S and edge-opened graphite oxide, chemical reduction of graphene oxide and deposition of S. [23][24][25] Because the S in these graphene-S composites is not completely encapsulated by graphene, the polysulfi de intermediates still slowly dissolve into electrolyte resulting in progressive cycling decay. The ideal structure for the carbon-S composites is to intercalate S atoms or molecules into a graphite interlayer to form S intercalated graphite compounds, thus maximizing S loading and minimizing the dissolution of polysulfi des. However, only a small amount of S can be intercalated into graphite even under the conditions of high pressure and/or high temperature due to small layer spacing (planar distance ≈0.34 nm). [ 26 ] Because of the large interlayer distance, expanded graphite has been investigated as host to embed S. The expanded graphiteembedded sulfur nanocomposites were normally synthesized by two-step reactions: thermal reduction of graphite oxides in H 2 /Ar at a high temperature (450 °C) and fl owed by S meltdiffusion at a low temperature of ≈155 °C. [ 27,28 ] Since S vapor can reduce graphite oxide (GO) at a high temperature, in this work we report a novel one-step method to synthesize S intercalated graphite by S in situ reducing GO and intercalating into the reduced graphite oxide (RGO) under vacuum at 600 °C. Figure 1 schematically depicts the preparation process of the RGO/S composite. At room temperature, sulfur exists mainly in the form of cyclooctasulfur (S 8 ), as heating the mixture of graphite oxide and S 8 to 600 °C, the large molecule S 8 will be broken into smaller chain species S 2 . [ 29,30 ] Due to the large interplanar distance of GO, these S 2 molecules can intercalate into GO to deoxygenate GO and form SO 2 gas. [ 31 ] Further S 2 intercalation into RGO will form S intercalated graphite compounds. By manipulating the interlayer distance of graphite oxide through controlling the degree of oxidation of graphite, [ 32 ] the S intercalation level can be maximized. However, the S 2 molecules deposited on the external surface and the edges of RGO interlayer may recombine to form cyclo-S 8 when the temperature is cooling down from 600 °C to room temperature. Due to the high solubility of CS 2 to S 8 , the surface S 8 can be removed using CS 2 solvent at ease. Here, we demonstrate that the RGO/S composites with 52% S loading show high capacities and long cycling stabilities. The CS 2 -wash treatment can further enhance the cycling stability of RGO/S composites. Almost no capacity decline can be observed for CS 2 -washed RGO/S composites in 225 cycles. Figure 2 a shows the X-ray diffraction (XRD) patterns of pure S, pristine graphite, GO and RGO/S composite. The XRD pattern of S exhibits very sharp and strong peaks throughout the entire diffraction range, indicating a well-defi ned crystal S 8 structure. Graphite exhibits a sharp peak at 2 θ = 26.6° corresponding to the diffraction of (002) plane with interlayer distance of ≈0.34 nm. [ 33 ]

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“…AC500, AC700 and AC800 show VB12 equilibrium adsorption of 983, 587 and 452 mg/g, respectively. As is known, pore structure and surface chemical property are main factors affecting adsorption performance [30][31][32][33][34].…”

Section: Adsorption Of Vb12mentioning

confidence: 99%