Unique behaviour of nonsolvents for polysulphides in lithium–sulphur batteries

Cuisinier, Marine; Cabelguen, Pierre‐Etienne; Adams, Brian D.; Garsuch, Arnd; Balasubramanian, M.; Nazar, Linda F.

doi:10.1039/c4ee00372a

Cited by 349 publications

(426 citation statements)

References 34 publications

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“…In sharp contrast, the lithiation process in typical nonaqueous electrolytes based on 1,3-dioxalane and dimethoxyethane normally undergoes three distinct stages with varying kinetics, which correspond to phase changes from solid S 8 to soluble S x 2− species (x > 4) followed by isolated solid Li 2 S x (x = 2 and 1) (32), accompanied by much higher potential hysteresis. A single-potential plateau similar to this work has been observed in the Li/S cell with a solid-state electrolyte (34), but still with much higher overpotential. The aqueous sulfur chemistry described in this work provides an avenue to exploit this cheap and energy-dense cathode material.…”

Section: Resultssupporting

confidence: 68%

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Yang

Suo

Borodin

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

172

182

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Leveraging the most recent success in expanding the electrochemical stability window of aqueous electrolytes, in this work we create a unique Li-ion/sulfur chemistry of both high energy density and safety. We show that in the superconcentrated aqueous electrolyte, lithiation of sulfur experiences phase change from a highorder polysulfide to low-order polysulfides through solid-liquid two-phase reaction pathway, where the liquid polysulfide phase in the sulfide electrode is thermodynamically phase-separated from the superconcentrated aqueous electrolyte. The sulfur with solid-liquid two-phase exhibits a reversible capacity of 1,327 mAh/(g of S), along with fast reaction kinetics and negligible polysulfide dissolution. By coupling a sulfur anode with different Li-ion cathode materials, the aqueous Li-ion/sulfur full cell delivers record-high energy densities up to 200 Wh/(kg of total electrode mass) for >1,000 cycles at ∼100% coulombic efficiency. These performances already approach that of commercial lithium-ion batteries (LIBs) using a nonaqueous electrolyte, along with intrinsic safety not possessed by the latter. The excellent performance of this aqueous battery chemistry significantly promotes the practical possibility of aqueous LIBs in large-format applications.water-in-salt | rechargeable aqueous battery | aqueous sulfur battery | gel polymer electrolyte | phase separation I n the past two decades, rechargeable lithium-ion batteries (LIBs) have revolutionized consumer electronics with their high energy density and excellent cycling stability, and are the state-of-the-art candidates for applications ranging from kilowatt hours for electric vehicles up to megawatt hours for grids (1, 2). The latter applications in large-format present much more stringent requirements for safety, cost, and environmental friendliness, besides energy density and cycle life. The shortcomings of LIB are mostly due to the flammable and toxic nonaqueous electrolytes and moderate energy densities (<400 Wh·kg −1 ) provided by the electrochemical couples currently used (3). Among the various "beyond Li-ion" high-energy chemistries (>500 Wh·kg −1 ) explored currently, the nonaqueous lithium/sulfur (Li/S) battery based on sulfur as a cathode (theoretical capacity of 1,675 mAh·g −1 ) and metallic lithium as an anode seems to be the most practical, as evidenced by the mushrooming literature and significant advances in this system in the past 5 y (4-7). However, commercialization of this system still faces challenges because of severe safety concerns associated with the dendrite growth of metallic Li anode in highly inflammable ether-based electrolytes (8), and the high self-discharge associated with parasitic shuttling of the intermediate polysulfide species. Moreover, the moisture-sensitive nature of the nonaqueous electrolyte would contribute significantly to the cost of the Li/S battery pack due to the stringent moisture-exclusion infrastructure required during the manufacturing, processing, and packaging of the cells. The indispensabl...

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Section: Resultssupporting

confidence: 68%

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Yang

Suo

Borodin

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

172

182

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“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Other approaches have focused on designing new electrolytes with limited polysulfide solubility thereby suppressing the polysulfide shuttle leading to excellent coulombic efficiency and improved capacity retention. 24,25 These solvate electrolyte concepts have also shown improved coulombic efficiency in the cycling of the lithium metal. [24][25][26][27] For the passivation of the Li-anode in Li-S cells, the addition of LiNO 3 to the electrolyte is found to be effective in temporarily increasing the coulombic efficiency to greater than 99%.…”

mentioning

confidence: 99%

“…24,25 These solvate electrolyte concepts have also shown improved coulombic efficiency in the cycling of the lithium metal. [24][25][26][27] For the passivation of the Li-anode in Li-S cells, the addition of LiNO 3 to the electrolyte is found to be effective in temporarily increasing the coulombic efficiency to greater than 99%. [28][29][30][31] The use of protective Li-ion conducting ceramics 32 or polymeric membranes 31 are also shown to improve the stability of the Li-anode.…”

mentioning

confidence: 99%

Critical Link between Materials Chemistry and Cell-Level Design for High Energy Density and Low Cost Lithium-Sulfur Transportation Battery

Eroğlu

Zavadil

Gallagher

2015

J. Electrochem. Soc.

210

281

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A materials-to-system analysis for the lithium-sulfur (Li-S) electric vehicle battery is presented that identifies the key electrode and cell design considerations from reports of materials chemistry. The resulting systems-level energy density, specific energy and battery price as a function of these parameters is projected. Excess lithium metal amount at the anode and useable specific capacity, electrolyte volume fraction, sulfur to carbon ratio and reaction kinetics at the cathode are all shown to be critical for the high energy density and low cost requirements. Electrode loading is determined as a key parameter to relate the battery price for useable energy to the investigated design considerations. The presented analysis proposes that electrode loadings higher than 8 mAh/cm 2 (∼7 mg S/cm 2 ) are necessary for Li-S systems to exhibit the high energy density and low cost required for transportation applications. Stabilizing the interface of lithium metal at the required current densities and areal capacities while simultaneously maintaining cell capacity with high sulfur loading in an electrolyte starved cathode are identified as the key barriers for ongoing research and development efforts to address. In the search for high energy density and inexpensive rechargeable batteries for the electric vehicles, Li-S batteries have gained significant attention due to the high specific capacity (1675 mAh/g), low cost, natural abundance and non-toxicity of elemental sulfur.1-6 Compared to the state-of-art Li-ion batteries, Li-S batteries have very high theoretical specific energy of 2567 Wh/kg.1-6 The Li-S battery is commonly composed of a sulfur-carbon composite cathode, an organic electrolyte and a lithium anode.1-6 The overall Li-S redox reaction is given in equation 1.with a standard potential of U 0 = 2.2 V (vs Li/Li + ). 1,2Despite these attractive features of the Li-S battery, multiple formidable challenges limit the cycle life significantly. [1][2][3][4][5][6] Firstly, precipitation of insulating reactants, sulfur and Li 2 S, in the cathode leads to poor electronic conductivity and passivation that could limit the active material utilization.1-6 Secondly, the soluble polysulfide reaction intermediates produced during charging can migrate to the anode where they react with Li to either precipitate on the anode surface or migrate back to the cathode causing infinite charging.1-6 This polysulfide shuttle mechanism leads to poor coulombic efficiency and significant self-discharge as well as corrosion of the Li-anode.1-6 Finally, the instability of the Li-anode is a major concern.2,4,5,7 Li surface area can increase significantly with cycling due to morphological changes, which accelerate Li and electrolyte depletion owing to the absence of a stable interphase. 2,4,5,7 While polysulfide migration may lead to the corrosion of dendritic or high surface area lithium reducing the risk of short circuiting, the resulting reactions typically result in a reduction in inventory of cyclable lithium. 4 All of these mechanisms ...

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“…LiTFSI is still soluble. 31,32 However, the conductivity is one order of magnitude lower than that of DME/DOLelectrolytes.Despite the above advantages of liquid electrolytes, in effective, organic solvents, may be with the exception of those sufficiently fluorinated and that of ionic liquids, are highly flammable and cause safety concerns. Hence, solid-state Li-ion conductors, encompassing inorganic electrolytes and organic polymer electrolytes (PEs), have emerged as promising alternatives to these conventional liquid electrolytes, possibly enabling the development of safe rechargeable Li-S batteries.…”

mentioning

confidence: 99%

“…LiTFSI is still soluble. 31,32 However, the conductivity is one order of magnitude lower than that of DME/DOLelectrolytes.…”

mentioning

confidence: 99%

Review—Solid Electrolytes for Safe and High Energy Density Lithium-Sulfur Batteries: Promises and Challenges

Judez

Zhang

et al. 2017

J. Electrochem. Soc.

155

128

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All-solid-state lithium-sulfur batteries (ASSLSBs) offer a means to enhance the energy density and safety of the state-of-art lithiumion batteries (LIBs), due to their high gravimetric energy density, low cost and environmental benignancy. In this work, the status of the research advances and perspectives on several types of solid electrolytes (SEs) developed for ASSLSBs are reviewed. The promises and challenges of utilizing SEs are discussed taking into account both theoretical calculation and experimental results, in hope of shedding some lights on future design of high energy density, cost competitive, and safe Li-S batteries. Lithium-sulfur (Li-S) batteries have been extensively investigated for lightweight applications (e.g., aircraft, artificial satellite, and unmanned aerial vehicles), and large-scale stationary energy storage, owing to their high gravimetric energy density, low cost, and environmental friendliness.1-3 The deployment of Li-S batteries into commercial market is hampered by several seemingly intrinsic problems resulting from the complex cell chemistry. Firstly, the electronically insulating nature of elemental sulfur (S 8 ) and end-product lithium sulfide (Li 2 S) leads to unstable electrochemical contact within S cathode. [4][5][6][7] Secondly, the soluble intermediates of polysulfide (PS) can diffuse between the cathode and anode (i.e., shuttle effect of PS), generating an active material loss in S cathode and degrading metallic Li anode. [4][5][6][7][8][9] Thirdly, the formation of 'dead' Li and Li dendrites upon cycling could not only decrease the Coulombic efficiency but also raise safety issues. [10][11][12] In recent years, various strategies have been attempted to overcome the above-mentioned problems. Most of the efforts have been devoted to enhance the electrochemical performance of Li-S batteries using well-designed cathode materials. 13 The diffusion of polysulfide species generated during discharge into electrolytes can be significantly suppressed by infusing sulfur into carbon materials in the cathode with an adequately controlled and engineered porosity and pore size, thus increasing the practical capacity and cyclability of Li-S batteries. These rational and creative strategies of cathode design have been covered by a number of recent reviews. 7,14,15 Besides, new binders (e.g., poly(ethylene oxide) (PEO) 16 and carboxymethycellulose (CMC) 17,18 ) have been employed for guarantying the integrity of the morphology and structure of S cathode, and enhancing the adhesion to current collector. The modification of separators (e.g., multiwall carbon nanotubes coated polypropylene 19 and lithiated Nafion 20 ) have been also developed for reducing the migration of polysulfides, thus mitigating the shuttle effect of PS. 21Apart from the strategies mentioned above, another approach, focusing on electrolyte formulation and modification, has been proved to be effective. The performances of Li-S batteries are largely affected by the electrolyte recipes, such as the type and identity of so...

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Unique behaviour of nonsolvents for polysulphides in lithium–sulphur batteries

Abstract: Combination of a solvent–salt complex [acetonitrile(ACN)2–LiTFSI] with a hydrofluoroether (HFE) co-solvent unveils a new class of Li–S battery electrolytes that possess essentially no solubility for lithium polysulfides, yet exhibit excellent capacity and very good rate capability..

Cited by 349 publications

References 34 publications

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility

Critical Link between Materials Chemistry and Cell-Level Design for High Energy Density and Low Cost Lithium-Sulfur Transportation Battery

Review—Solid Electrolytes for Safe and High Energy Density Lithium-Sulfur Batteries: Promises and Challenges

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