Graphene-enveloped sulfur in a one pot reaction: a cathode with good coulombic efficiency and high practical sulfur content

Evers, Scott; Nazar, Linda F.

doi:10.1039/c2cc16726c

Cited by 428 publications

(348 citation statements)

References 21 publications

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“…[7][8][9][10][11] Among many carbonaceous materials, graphene oxide-sulfur composites have been intensively reported as a novel material for preventing the loss of HOPSs through the adsorption and wrapping properties of graphene oxide. [12][13][14][15][16] Despite significantly enhancing the electrochemical stability, these systems can be further improved by exhibiting better structural integrity. 17 In previous studies, both the S and graphene oxide used in batteries were reported to measure on the order of several micrometers; thus, conformal contact between graphene oxide and S is difficult to achieve, allowing HOPSs to be lost by repeated electrochemical cycling.…”

Section: Introductionmentioning

confidence: 99%

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

et al. 2016

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Lithium-sulfur (Li-S) batteries are expected to overcome the limit of current energy storage devices by delivering high specific energy with low material cost. However, the potential of Li-S batteries has not yet been realized because of several technical barriers. Poor electrochemical performance is mainly attributed to the low electrical conductivity of the fully charged and discharged species, the irreversible loss of polysulfide anions and the decrease in the number of electrochemically active reaction sites during battery operation. Here, we report that the introduction of graphene quantum dots (GQDs) into the sulfur cathode dramatically enhanced sulfur/sulfide utilization, yielding high performance. In addition, the GQDs induced structural integrity of the sulfur-carbon electrode composite by oxygen-rich functional groups. This hierarchical architecture enabled fast charge transfer while minimizing the loss of lithium polysulfides, which is attributed to the physicochemical properties of GQDs. The mechanisms through which excellent cycling and rate performance are achieved were thoroughly studied by analyzing capacity versus voltage profiles. Furthermore, experimental observations and theoretical calculations further clarified the role played by GQDs by proving that C-S bonding occurs. Thus, the introduction of GQDs into Li-S batteries will provide an important breakthrough allowing their use as high-performance and low-cost batteries for next-generation energy storage systems. INTRODUCTIONRechargeable lithium-ion batteries are widely used in various applications, such as portable devices, bio-medical implants and electric vehicles, because of their high energy and power density. 1,2 However, current lithium-ion batteries based on the graphite and transition metal oxide couple have nearly reached their ceiling with respect to storage capability because of the limitations associated with their electrical properties and crystal structure. Therefore, breakthroughs in new energy storage systems that can surpass the current performance barrier of lithium-ion batteries should be brought about in a timely manner. Recently, Li-S batteries that can operate by the reversible electrochemical transformation between sulfur (S 8 ) and dilithium sulfide (Li 2 S) have attracted great attention because they can deliver high energy with a moderate voltage owing to the direct use of

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Section: Introductionmentioning

confidence: 99%

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

et al. 2016

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“…These include solid-state electrolytes [8][9][10] that show much promise for future development in conjunction with an ionically conductive sulphur cathode 11 . More effort, to date, has been devoted to the cathode side in order to physically confine the LiPSs within the pores or layers of carbonaceous materials that include mesoporous carbon 12 , hollow porous carbon spheres 13,14 , graphene 15,16 , conductive polymer nanotubes 17 and carbon interlayers 18 . However, over long-term cycling, the hydrophilic LiPSs diffuse out from the hydrophobic pores.…”

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confidence: 99%

Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries

et al. 2014

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The lithium-sulphur battery relies on the reversible conversion between sulphur and Li 2 S and is highly appealing for energy storage owing to its low cost and high energy density. Porous carbons are typically used as sulfur hosts, but they do not adsorb the hydrophilic polysulphide intermediates or adhere well to Li 2 S, resulting in pronounced capacity fading. Here we report a different strategy based on an inherently polar, high surface area metallic oxide cathode host and show that it mitigates polysulphide dissolution by forming an excellent interface with Li 2 S. Complementary physical and electrochemical probes demonstrate strong polysulphide/Li 2 S binding with this 'sulphiphilic' host and provide experimental evidence for surface-mediated redox chemistry. In a lithium-sulphur cell, Ti 4 O 7 /S cathodes provide a discharge capacity of 1,070 mAh g À 1 at intermediate rates and a doubling in capacity retention with respect to a typical conductive carbon electrode, at practical sulphur mass fractions up to 70 wt%. Stable cycling performance is demonstrated at high rates over 500 cycles.

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“…The viscosity of PEGDME+LiNO 3 electrolyte is much higher 23 times than DOL/DME+LiNO 3 electrolyte from the experimental results, which further confirms the different migration ability of LiNO 3 . To compare the electrochemical properties in this work to those with similar components reported in the literature [6,10,[27][28][29][30], the results for various S/graphene cathodes are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 98%

The electrochemical properties of high-capacity sulfur/reduced graphene oxide with different electrolyte systems

Wang

Chou

Liu

et al. 2013

Journal of Power Sources

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Dou, S. Xue. (2013). The electrochemical properties of high-capacity sulfur/reduced graphene oxide with different electrolyte systems. Journal of Power Sources, 244 (December), 240-245.The electrochemical properties of high-capacity sulfur/reduced graphene oxide with different electrolyte systems AbstractThe lithium/sulfur battery is a promising electrochemical system with high capacity, which is well-known to undergo a complex multistep reaction during the discharge process. Two types of electrolytes including poly (ethylene glycol) dimethyl ether (PEGDME)-based and 1.3 -dioxolane (DOL)/ dimethoxyethane (DME)-based electrolytes were investigated here. Furthermore, LiNO3 additive was introduced into the electrolyte in order to effectively eliminate the overcharge effect. The lithium sulfur battery with 1.0 M LiN(CF3SO2)2 in PEGME with 0.1 M LiNo3 shows highly stable reversible capacity of 624.8 mAh g-1 after 200 cycles and improved average coulombic efficiency of 98 percent. AbstractThe lithium/sulfur battery is a promising electrochemical system with high capacity, which is well-known to undergo a complex multistep reaction during the discharge process. Two types of electrolytes including poly(ethylene glycol) dimethyl ether (PEGDME)-based and 1,3-dioxolane (DOL)/dimethoxyethane (DME)-based electrolytes were investigated here. Furthermore, LiNO 3 additive was introduced into the electrolyte in order to effectively eliminate the overcharge effect. The lithium sulfur battery with 1.0 M LiN(CF 3 SO 2 ) 2 in PEGDME with 0.1M LiNO 3 shows highly stable reversible capacity of 624.8 mAh g -1 after 200 cycles and improved average coulombic efficiency of 98 %.

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Graphene-enveloped sulfur in a one pot reaction: a cathode with good coulombic efficiency and high practical sulfur content

Cited by 428 publications

References 21 publications

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries

The electrochemical properties of high-capacity sulfur/reduced graphene oxide with different electrolyte systems

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