A high performance lithium–sulfur battery enabled by a fish-scale porous carbon/sulfur composite and symmetric fluorinated diethoxyethane electrolyte

Gao, Mengyao; Su, Chi‐Cheung; He, Meinan; Glossmann, Tobias; Hintennach, Andreas; Feng, Zhenxing; Huang, Yaqin; Zhang, Zhengcheng

doi:10.1039/c7ta01057e

Cited by 43 publications

(18 citation statements)

References 45 publications

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“…The SEM images (Figure S12, Supporting Information) of discharged electrodes in different electrolytes also showed that without the formation of SEI layer, lots of plate‐like structures formed, indicating the dissolution of polysulfides/polyselenides from the carbon host. Similar plate‐like discharge products formation has also been observed in the case of Li/S battery that undergoes severe shuttle effect using DOL/DME‐based electrolytes . While no obvious structure changes can be observed in the HFE‐based electrolytes, confirming bypassed formation of polysulfides/polyselenides via the help of SEI layer.…”

Section: Resultssupporting

confidence: 73%

Solid‐State Lithium/Selenium–Sulfur Chemistry Enabled via a Robust Solid‐Electrolyte Interphase

Sun

Luo

et al. 2018

Advanced Energy Materials

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Lithium/selenium‐sulfur batteries have recently received considerable attention due to their relatively high specific capacities and high electronic conductivity. Different from the traditional encapsulation strategy for suppressing the shuttle effect, an alternative approach to directly bypass polysulfide/polyselenide formation via rational solid‐electrolyte interphase (SEI) design is demonstrated. It is found that the robust SEI layer that in situ forms during charge/discharge via interplay between rational cathode design and optimal electrolytes could enable solid‐state (de)lithiation chemistry for selenium‐sulfur cathodes. Hence, Se‐doped S22.2Se/Ketjenblack cathodes can attain a high reversible capacity with minimal shuttle effects during long‐term and high rate cycling. Moreover, the underlying solid‐state (de)lithiation mechanism, as evidenced by in situ 7Li NMR and in operando synchrotron X‐ray probes, further extends the optimal sulfur confinement pore size to large mesopores and even macropores that have been long considered as inferior sulfur or selenium host materials, which play a crucial role in developing high volumetric energy density batteries. It is expected that the findings in this study will ignite more efforts to tailor the compositional/structure characteristics of the SEI layers and the related ionic transport across the interface by electrode structure, electrolyte solvent, and electrolyte additive screening.

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Section: Resultssupporting

confidence: 73%

Solid‐State Lithium/Selenium–Sulfur Chemistry Enabled via a Robust Solid‐Electrolyte Interphase

Sun

Luo

et al. 2018

Advanced Energy Materials

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“…Yet, another approach, and the one we target here, is to use electrolytes that sparsely dissolve PS e. g . highly concentrated or fluorinated ether‐based electrolytes …”

Section: Figurementioning

confidence: 99%

Monitoring Polysulfide Solubility and Diffusion in Fluorinated Ether‐Based Electrolytes by Operando Raman Spectroscopy

Bouchal

Boulaoued

Johansson

2020

Batteries & Supercaps

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Polysulfide (PS) solubility is a key property of LiÀ S battery electrolytes for the conversion reaction(s) at the electrolyteelectrode interface. When PSs shuttle between the composite C/S cathode and the lithium metal anode, however, this leads to a continuous loss of active material and thus rapid capacity fading. In order to restrict the shuttle effect, fluorinated ethers have recently been proposed as a remedy; by only sparsely dissolving PSs they physically block the diffusion. We show here how the diffusion of PSs in fluorinated ethers, as monitored by operando Raman spectroscopy, is selective and that only shortchain PS (S 2À 4 ) are soluble and diffuse. This fundamental observation can be used to further leverage the practical performance of LiÀ S batteries by novel electrolyte design.For a more sustainable future without fossil energy, the electrification of vital markets such as transportation and largescale grid storage is a key, but they require high energy density batteries for longer driving ranges and smarter storage capabilities. [1][2][3] Although current lithium-ion battery cells can reach up to ca. 300 W · h · kg À 1 these can hardly satisfy the fastexpanding demand, [4] why the development of batteries with even higher energy density, longer cycle-life and acceptable levels of safety is critically needed. [3,5,6] Lithium-sulfur (LiÀ S) batteries are considered as one of the most promising rechargeable battery technologies due to that sulfur is abundant and non-toxic, and meets the requirements of renewable and clean energy development. [5,6] Today, LiÀ S battery cells can deliver 400-500 W · h · kg À 1 , but only with a relatively short cycle-life, which considerably restricts any largescale commercialization. [7] The electrochemical reactions of LiÀ S batteries involve complicated conversion reactions based on multi-electron transfer, generating a series of intermediate soluble polysulfide (PS) species Li 2 S n (4 � n � 8). [8] The PS intermediates not only dissolve into the electrolyte, causing severe loss of active material, but also shuttle between the anode and the cathode without performing useful work. This shuttling results in low Coulombic efficiency, relatively short cycle-life, and increased internal cell resistance. [9,10] Therefore, the control of PS solubility and diffusion are keys to achieve more performant LiÀ S batteries.Several approaches have been used to tackle the shuttling; [9] mainly by protecting the lithium surface by e. g. adding LiNO 3 to the electrolyte, [11][12][13][14] but this is at the expense of reduced cell voltage and is seriously plagued by gradual decay upon cycling. Another approach is to trap the PS in or close to the C/S composite cathode. [9,15] Yet, another approach, and the one we target here, is to use electrolytes that sparsely dissolve PS e. g. highly concentrated [16] or fluorinated etherbased electrolytes. [17][18][19][20][21][22][23][24] Sulfur and PS solubility in fluorinated ethers are several orders of magnitude lower as compared to linear g...

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“…This approach proved to be successful in enhancing the coulombic efficiency of the Li-S batteries. [23][24][25][26][27] Moreover, several groups have indicated the importance of the solvent solvation state in the LiPS dissolution process. [28][29][30] As ar esult, an in-depth understanding of the relationship between LiPS dissolution and the solvation of electrolyte solvents is vital in developing efficient Li-S batteries.…”

mentioning

confidence: 99%

The Relationship between the Relative Solvating Power of Electrolytes and Shuttling Effect of Lithium Polysulfides in Lithium–Sulfur Batteries

Amine

et al. 2018

Angew Chem Int Ed

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Relative solvating power, that is, the ratio of the coordination ratios between a solvent and the reference solvent, was used to probe the quantitative structure-activity relationship of electrolyte solvents and the lithium polysulfide (LiPS) dissolution in lithium-sulfur batteries. Internally referenced diffusion-ordered nuclear magnetic resonance spectroscopy (IR-DOSY) was used to determine the diffusion coefficient and coordination ratio, from which the relative solvating power can be easily measured. The higher the relative solvating power of an ethereal solvent, the more severe will be the LiPS dissolution and the lower the coulombic efficiency of the lithium-sulfur battery. A linear relationship was established between the logarithm of relative solvating power of a solvent and the degree of LiPS dissolution, rendering relative solvating power an important parameter in choosing the electrolyte solvent for lithium-sulfur batteries.

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A high performance lithium–sulfur battery enabled by a fish-scale porous carbon/sulfur composite and symmetric fluorinated diethoxyethane electrolyte

Abstract: A high performance lithium–sulfur (Li–S) battery comprising a symmetric fluorinated diethoxyethane electrolyte coupled with a fish-scale porous carbon/S composite electrode was demonstrated.

Cited by 43 publications

References 45 publications

Solid‐State Lithium/Selenium–Sulfur Chemistry Enabled via a Robust Solid‐Electrolyte Interphase

Solid‐State Lithium/Selenium–Sulfur Chemistry Enabled via a Robust Solid‐Electrolyte Interphase

Monitoring Polysulfide Solubility and Diffusion in Fluorinated Ether‐Based Electrolytes by Operando Raman Spectroscopy

The Relationship between the Relative Solvating Power of Electrolytes and Shuttling Effect of Lithium Polysulfides in Lithium–Sulfur Batteries

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