Manipulating electrolyte and solid electrolyte interphase to enable safe and efficient Li-S batteries

Zheng, Jing; Fan, Xiulin; Ji, Guangbin; Wang, Haiyang; Hou, Singyuk; DeMella, Kerry C.; Raghavan, Srinivasa R.; Wang, Jing; Xu, Kang; Wang, Chunsheng

doi:10.1016/j.nanoen.2018.05.065

Cited by 155 publications

(107 citation statements)

References 41 publications

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“…To overcome these disadvantages in using HCE, several groups have added a low-polarity cosolvent to dilute an HCE by forming a localized high-concentration electrolyte (LHCE). [29] However, none of the LHCE reported to date has been applied in PIBs, its stability and compatibility with PIBs remain in question.Herein, our work reports for the first time that a highly reversible K + insertion/extraction into graphite interlayer can Reversible intercalation of potassium-ion (K + ) into graphite makes it a promising anode material for rechargeable potassium-ion batteries (PIBs). Zhang's group used the bis(2,2,2,-tri-fluoroethyl) ether to dilute the concentrated lithium bis(fluorosulfonyl) imide (LiFSI)/dimethyl carbonate and improve the coulombic efficiency (CE) of lithium metal anodes without dendrite formation.…”

mentioning

confidence: 99%

Localized High‐Concentration Electrolytes Boost Potassium Storage in High‐Loading Graphite

Qin

Xiao

Zheng

et al. 2019

Advanced Energy Materials

185

155

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graphite has a theoretical capacity of 279 mAh g −1 . [3,17] In 2015, Ji and Hu have separately demonstrated the electrochemical intercalation of K ions into graphite in potassium hexafluorophosphate (KPF 6 )/ ethylene carbonate (EC)-diethyl carbonate (DEC) electrolytes. [4,18] However, their works did not achieve a highly reversible K + insertion/extraction process in KPF 6 /EC-DEC electrolyte because the formed solid electrolyte interphase (SEI) becomes fragile and unstable due to the large volume variation (≈60%) during K + insertion/extraction. [19,20] Compared to the conventional lowconcentration electrolyte (LCE), adopting a high-concentration electrolyte (HCE, e.g., >3 m) is a promising strategy to solve the above problem because it possesses some unusual physicochemical and electrochemical properties due to the unique solvation structure of ions, which make it different from an LCE. [21][22][23][24] In 2007, Jeong adopted the concentrated lithium bisperfluoroethylsulfonyl imide LiN(SO 2 C 2 F 5 ) 2 / propylene carbonate (PC) to realize a reversible graphite anode for lithium-ion batteries. [24] Recently, Komaba and Lu have reported the highly reversible graphite anode for PIBs at concentrated potassium bis(fluorosulfonyl)imide (KFSI)/ dimethoxyethane (DME) and KFSI/ethyl methyl carbonate electrolytes, respectively. [25,26] Despite these progresses, the issues of high viscosity, low ionic conductivity, and the increased cost of the HCE still hinder its practical applications. To overcome these disadvantages in using HCE, several groups have added a low-polarity cosolvent to dilute an HCE by forming a localized high-concentration electrolyte (LHCE). It is believed that the introduced cosolvent does not participate in the solvation process. Zhang's group used the bis(2,2,2,-tri-fluoroethyl) ether to dilute the concentrated lithium bis(fluorosulfonyl) imide (LiFSI)/dimethyl carbonate and improve the coulombic efficiency (CE) of lithium metal anodes without dendrite formation. [27] They also diluted concentrated LiFSI in sulfone with a fluorinated ether for high-voltage (4.9 V) lithium metal batteries. [28] Wang's group used the same cosolvent in the concentrated LiFSI/DME to increase both coulombic efficiencies of S cathode and Li anode for Li-S batteries. [29] However, none of the LHCE reported to date has been applied in PIBs, its stability and compatibility with PIBs remain in question.Herein, our work reports for the first time that a highly reversible K + insertion/extraction into graphite interlayer can Reversible intercalation of potassium-ion (K + ) into graphite makes it a promising anode material for rechargeable potassium-ion batteries (PIBs). However, the current graphite anodes in PIBs often suffer from poor cyclic stability with low coulombic efficiency. A stable solid electrolyte interphase (SEI) is necessary for stabilizing the large interlayer expansion during K + insertion. Herein, a localized high-concentration electrolyte (LHCE) is designed by adding a highly fluorinated ether into the con...

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mentioning

confidence: 99%

Localized High‐Concentration Electrolytes Boost Potassium Storage in High‐Loading Graphite

Qin

Xiao

Zheng

et al. 2019

Advanced Energy Materials

185

155

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“…[9] Since electrolytes play ac rucial role in determining the chemistries of the cathode and anode,d eveloping an ideal electrolyte system is an effective approach to improve LMB performance. [10,11] In this regard, electrolyte modulation including use of optimal solvents/co-solvents, [12][13][14][15] new or blended salts, [16][17][18] highly concentrated electrolytes (HCE), [19][20][21][22][23][24] localized HCE (LHCE), [25,26] and electrolyte additives [27,28] have been widely reported to enable stable Li stripping/plating.A lthough these electrolytes can also suppress polysulfide shuttle,the improved cycle performance of S cathodes is at the expense of low Sl oading and high electrolyte/sulfur (E/S) ratio (Supporting Information, Table S1). Zhang et al reported that Li-S cells with concentrated LiTFSI/DOL-DME electrolytes can deliver 600 mAh g À1 after 200 cycles at C/5, but based on thin S electrodes (1 mg cm À2 )a nd flooded electrolytes (37.5 mLmg À1 ).…”

Section: Introductionmentioning

confidence: 99%

Beyond the Polysulfide Shuttle and Lithium Dendrite Formation: Addressing the Sluggish Sulfur Redox Kinetics for Practical High‐Energy Li‐S Batteries

Zhao

et al. 2020

Angewandte Chemie

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Electrolyte modulation simultaneously suppresses polysulfide the shuttle effect and lithium dendrite formation of lithium–sulfur (Li‐S) batteries. However, the sluggish S redox kinetics, especially under high S loading and lean electrolyte operation, has been ignored, which dramatically limits the cycle life and energy density of practical Li‐S pouch cells. Herein, we demonstrate that a rational combination of selenium doping, core–shell hollow host structure, and fluorinated ether electrolytes enables ultrastable Li stripping/plating and essentially no polysulfide shuttle as well as fast redox kinetics. Thus, high areal capacity (>4 mAh cm−2) with excellent cycle stability and Coulombic efficiency were both demonstrated in Li metal anode and thick S cathode (4.5 mg cm−2) with a low electrolyte/sulfur ratio (10 μL mg−1). This research further demonstrates a durable Li‐Se/S pouch cell with high specific capacity, validating the potential practical applications.

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“…A high concentration of Na salts in electrolytes was found to be favorable for the plating‐stripping performance of Na metal anodes . These highly concentrated electrolytes are very promising for suppressing polysulfide shuttle reactions on the S cathode side . Moreover, the electrolyte additives serve another very important function, modification of the SEI surface.…”

Section: Discussionmentioning

confidence: 99%

Remedies for Polysulfide Dissolution in Room‐Temperature Sodium–Sulfur Batteries

et al. 2019

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S and Na 2 S 5 is present; but Na 2 S 2 or Na 2 S cannot exist in the liquid state due to their high melting points at 470 and 1168 °C, respectively. Accordingly, there are three types of NaS batteries with different operating temperature regions, including HT (270-350 °C), [4] intermediate temperature (IT,, [5] and room temperature (RT), [6] which have been developed with different cell configurations. [7] As illustrated in Figure 1b, HT-NaS and IT-NaS batteries are typically constructed in a tubular design by using metal cases, which contain central molten Na as the cathode, which is confined in a beta-alumina solid electrolyte (BASE) tube with a molten S cathode surrounding the tube due to the high operation temperature. [8] NGK Insulator, Inc. commercialized the HT-NaS system in Japan in 2002, storing megawatt-size energy for utility-based load-leveling and peak-shaving applications. [1a,9] With a relatively lower operation temperature, the IT-NaS batteries show inferior S utilization and reversible capacity due to the lower ionic conductivity of BASE, but they are likely to deliver higher capacity and energy density in the future, if Na 2 S 2 or Na 2 S could be further formed reversibly with a special cell configuration. [5,10] For the typical HT-NaS and IT-NaS batteries, with active Na (melting point, T m = 98 °C) and S (T m = 119 °C) in the liquid state in this temperature range, Na ions can migrate through the BASE to react with S, leading to the formation of Na 2 S x (x = 5-3) during the discharge process, which will lead, in turn, to a relatively low theoretical gravimetric capacity of 557 mA h g −1 and specific energy density of 760 W h kg −1 . [4,7] The high operation temperature was found to be the culprit, under which both molten S and polysulfides are highly corrosive toward sealing components with a high risk of short-circuits, thus causing serious safety concerns, increasing energy loss, and high additional costs associated with cell packing for thermal-corrosion resistance. Another leading challenge is that the production yields and high cost of BASE become an issue for large-scale grid applications. [1c] For RT-NaS batteries, typical coin-type cells can be utilized for performance evaluation, in which metallic sodium and a solid sulfur-carbon (S/C) composite work as the anode and cathode, respectively, which are separated by a membrane, while a liquid electrolyte, consisting of organic solvents and dissolved Na salts can be poured into the cell to transport Na ions (Figure 1c). In contrast, S can be theoretically reduced to Na 2 S during discharge based on a two-electron reaction, corresponding to a greatly increased specific energy of Rechargeable room-temperature sodium-sulfur (RT-NaS) batteries represent one of the most attractive technologies for future stationary energy storage due to their high energy density and low cost. The S cathodes can react with Na ions via two-electron conversion reactions, thus achieving ultrahigh theoretical capacity (1672 mAh g −1 ) and specific energy (1273...

show abstract

Manipulating electrolyte and solid electrolyte interphase to enable safe and efficient Li-S batteries

Cited by 155 publications

References 41 publications

Localized High‐Concentration Electrolytes Boost Potassium Storage in High‐Loading Graphite

Localized High‐Concentration Electrolytes Boost Potassium Storage in High‐Loading Graphite

Beyond the Polysulfide Shuttle and Lithium Dendrite Formation: Addressing the Sluggish Sulfur Redox Kinetics for Practical High‐Energy Li‐S Batteries

Remedies for Polysulfide Dissolution in Room‐Temperature Sodium–Sulfur Batteries

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