Understanding dynamics of polysulfide dissolution and re-deposition in working lithium–sulfur battery by in-operando transmission X-ray microscopy

Lin, Chia-Hsien; Chen, Wen‐Chin; Song, Yen‐Fang; Wang, Chun‐Chieh; Tsai, Li‐Duan; Wu, Nae‐Lih

doi:10.1016/j.jpowsour.2014.04.003

Cited by 77 publications

(62 citation statements)

References 20 publications

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“…[ 39 ] The fi rst anodic scan shows two broad oxidation peaks centered at 2.69 and 3.54 V, respectively, corresponding to electrochemical conversion of Li 2 S to S or polysulfi des, which is similar to our previous reports and other references based on Li 2 S−C cathodes. [ 3 ] The subsequent cathodic scan shows two broad reduction peaks centered at 2.23 and 1.99 V, respectively, corresponding to transformation of polysulfi des or S into Li 2 S. The reversible processes are found in the following cycles.…”

Section: Shown Insupporting

confidence: 89%

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

Qiu

Rong

Yang

et al. 2015

Advanced Energy Materials

102

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an effective strategy for the redeposition of lithium polysulfi des due to their affi nities for these materials, which leads to significant improvement of corresponding Li/S cells.Li 2 S is a promising prelithiated cathode material with a high theoretical capacity of 1166 mA h g −1 . Unlike conventional sulfur cathode, Li 2 S cathode shrinks as it delithiates initially, producing voids for subsequent lithiation/delithiation cycling, hence protecting the electrode structure from damage. More importantly, Li 2 S can be matched with lithium metal-free anodes (such as silicon and tin), thus eliminating serious safety issues associated with the formation of "dendrites." Despite of these merits, the performance of Li 2 S-based cathode significantly lags behind its sulfur counterpart. [ 9,10,30,31 ] A key issue for the Li 2 S material seems to be in its ineffi cient activation and redeposition process. [ 32,33 ] To understand the actual electrochemical activation processes, we fi rst developed in situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques to study the cathode material structural changes on delithiation. The newly developed in situ SEM set-up is shown in Figure 1 a,b. A liquid cell contains one electrode with graphene and Li 2 S particles on a 50 nm thick SiN x window, and the other electrode with Li metal on Cu foil. The cell is fi lled by a liquid electrolyte (see the Experimental Section). When charged at 3.5 V, the conversion reaction from Li 2 S to polysulfi des occurs fi rst at their surfaces (Figure 1 c and Figure S1 and Movie 1, Supporting Information). We see that the Li 2 S particles on graphene become smaller and smaller upon charging due to gradual dissolution of lithium polysulfi des into the electrolyte. The phenomenon is also supported by in situ Raman spectroscopy (see Figure S2, Supporting Information). The observed phenomenon could be explained by that Li 2 S was chemically converted to soluble lithium polysulfi des upon charging. The process was further examined by in situ TEM study. A newly designed in situ TEM microchip (Figure 1 d) was fabricated and schematically shown in Figure 1 e. The main part is an Au wire, of which one end was connected to one electrode of the chip by silver paste, and the other end was glued with the graphene− Li 2 S sample. The surface of the other electrode of the chip was deposited by Li metal. The graphene−Li 2 S sample and Li metal were connected via an ionic liquid electrolyte. When charged at 3.5 V, Li 2 S particles encapsulated in the graphene gradually disappeared (Figure 1 f and Movie 2, Supporting Information). The processes could be explained by the dissolution of the generated lithium polysulfi des in the ionic liquid electrolyte. The observed The development of high-capacity cathode materials is critical for applications such as mobile devices and electric vehicles. Li/S batteries represent a promising system based on sulfurconductive additive composite as the cathode. [1][2][3][4][5] However, various factors ...

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Section: Shown Insupporting

confidence: 89%

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

Qiu

Rong

Yang

et al. 2015

Advanced Energy Materials

102

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“…One may notice that the peak intensity of S-S and C-S is much lower than that of R-OSO3 -, which is an intrinsic character of the XAS. The white line intensity depends on matrix elements and occupancy of any bound final states [50][51] . The rising edge XAS visible as the features at 2472.7 (S-S) and 2473.7 eV (C-S) is the low valent sulfur, while the high valent sulfur (R-OSO3 -) XAS maximizes near 2483.5 eV [52] .…”

Section: C D E)mentioning

confidence: 99%

Nucleophilic substitution between polysulfides and binders unexpectedly stabilizing lithium sulfur battery

et al. 2017

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Polysulfide shuttling has been the primary cause of failure in lithium-sulfur (Li-S) battery cycling. Here, we demonstrate an uncleophilic substitution reaction between polysulfides and binder functional groups can unexpectedly immobilizes the polysulfides. The substitution reaction is verified by UV-visible spectra and X-ray photoelectron spectra. The immobilization of polysulfide is in situ monitored by synchrotron based sulfur K-edge X-ray absorption spectra. The resulting electrodes exhibite initial capacity up to 20.4 mAh/cm 2 , corresponding to 1199.1 mAh/g based on a micron-sulfur mass loading of 17.0 mg/cm 2 . The micron size sulfur transformed into nano layer coating on the cathode binder during cycling.Directly usage of nano-size sulfur promotes higher capacity of 33.7 mAh/cm 2 , which is the highest areal capacity reported in Li-S battery. This enhance performance is due to the reduced shuttle effect by covalently binding of the polysulfide with the polymer binder.2

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“…It is known that sulfur cathode materials possess high theoretical energy, but their cyclability and power characteristics are low because of the shuttle effect, i.e., the transport of soluble polysulfides between both electrodes, including the charge "shuttle" that accompanies this mass transport. 2 Researchers have addressed this issue by coating the sulfur cathode with a carbon material or a conductive polymer to suppress the dissolution of polysulfides. Graphene, [3][4][5][6] carbon nanotubes (CNTs), [7][8][9] and carbon [10][11][12] have been investigated as sulfurbased cathode materials.…”

Section: Introductionmentioning

confidence: 99%

A Simple Preparation of Polyaniline-coated Sulfur Composites for use as Cathodes in Li–S Batteries

Hyun

Lee

Jung³

et al. 2016

Electrochemistry

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A polyaniline (PANi)-coated sulfur cathode was prepared by in-situ polymerization to improve the performance of Li-S batteries and prevent polysulfide dissolution. Because PANi polymerization requires only the addition of sulfur powder, the polymerization method was simple. Battery performance testing was conducted using various sulfur ratios, with the best performance being exhibited by the 31 wt% sulfur PANi composite (approximately 500 mAh g −1 S after 50 cycles from an initial capacity of 903 mAh g −1 S). Transmission electron microscopy images confirmed that sulfur was coated by an approximately 10-nm-thick layer of PANi. Cycle testing was conducted at a rate of 0.2 C with an electrode loading of 2 mg cm −2 of sulfur. Thus, a highly homogenous distribution of sulfur particles in PANi was achieved, resulting in sulfur-coated composite materials and allowing for the preparation of a conductive polymer by a relatively simple sulfur distribution method.

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Understanding dynamics of polysulfide dissolution and re-deposition in working lithium–sulfur battery by in-operando transmission X-ray microscopy

Cited by 77 publications

References 20 publications

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

Nucleophilic substitution between polysulfides and binders unexpectedly stabilizing lithium sulfur battery

A Simple Preparation of Polyaniline-coated Sulfur Composites for use as Cathodes in Li–S Batteries

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Understanding dynamics of polysulfide dissolution and re-deposition in working lithium–sulfur battery by in-operando transmission X-ray microscopy

Cited by 77 publications

References 20 publications

Highly Nitridated Graphene–Li2S Cathodes with Stable Modulated Cycles

Highly Nitridated Graphene–Li2S Cathodes with Stable Modulated Cycles

Nucleophilic substitution between polysulfides and binders unexpectedly stabilizing lithium sulfur battery

A Simple Preparation of Polyaniline-coated Sulfur Composites for use as Cathodes in Li&ndash;S Batteries

Contact Info

Product

Resources

About

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

Highly Nitridated Graphene–Li₂S Cathodes with Stable Modulated Cycles

A Simple Preparation of Polyaniline-coated Sulfur Composites for use as Cathodes in Li–S Batteries