X-ray Absorption Spectroscopy Characterization of a Li/S Cell

Ye, Yifan; Kawase, Ayako; Song, Min‐Kyu; Feng, Bo; Liu, Yi‐Sheng; Marcus, Matthew A.; Feng, Jun; Cairns, Elton J.; Guo, Jinghua; Zhu, Junfa

doi:10.3390/nano6010014

Cited by 34 publications

(32 citation statements)

References 35 publications

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“…XAS peaks at different photon absorption energies typically represent different S-containing species. [25][26] Combining the XAS spectra profiles with scanning electron microcopy (SEM) morphological investigations and cell performance data, this study elucidates how CTAB is introduced into the cathode material during the sample preparation process, how it further modifies the surface of the S-coated GO, affects the micro structure of the S-GO nanocomposite and subsequently influences the cell performance. Finally, detailed elucidation of the structure-performance relationship for the S-GO nanocomposites is obtained.…”

Section: Introductionmentioning

confidence: 99%

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

Kawase

Song

et al. 2016

J. Phys. Chem. C

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We have investigated the chemical bonding interaction of S in a CTAB(cetyltrimethylammonium bromide, CH 3 (CH 2 ) 15 N + (CH 3 ) 3 Br -)-modified sulfur-graphene oxide (S-GO) nanocomposite used as the cathode material for Li/S cells by S K-edge X-ray absorption spectroscopy (XAS). The results show that the introduction of CTAB to the S-GO nanocomposite and changes in the synthesis recipe including alteration of the S precursor ratios and the sequence of mixing of ingredients lead to the formation of different S species. CTAB modifies the cathode materials through bonding with Na 2 S x in the precursor solution, which is subsequently converted to C-S bonds during the heat treatment at 155°C. Moreover, GO bonds with CTAB and acts as the nucleation center for S precipitation. All these interactions among S, CTAB and GO help to immobilize the sulfur in the cathode, and may be responsible for the enhanced cell cycle life of CTAB-S-GO nanocomposite-based Li/S cells.

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Section: Introductionmentioning

confidence: 99%

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

Kawase

Song

et al. 2016

J. Phys. Chem. C

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“…X-ray diffraction 32-34 and X-ray absorption spectroscopy (XAS) [35][36][37][38][39] have been used for operando experiments that focus on polysulfides, giving bulk, non-spatially resolved information. Transmission X-ray microscopy 33,40 provides spatiallyresolved microstructural information but lacks the ability to provide chemical information at the sulfur K-edge due to the hard X-ray energies needed for imaging.…”

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confidence: 99%

Operando Spectromicroscopy of Sulfur Species in Lithium-Sulfur Batteries

Miller

Kasse

Heath

et al. 2017

J. Electrochem. Soc.

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In this study, a novel cross-sectional battery cell was developed to characterize lithium-sulfur batteries using X-ray spectromicroscopy. Chemically sensitive X-ray maps were collected operando at energies relevant to the expected sulfur species and were used to correlate changes in sulfur species with electrochemistry. Significant changes in the sulfur/carbon composite electrode were observed from cycle to cycle including rearrangement of the elemental sulfur matrix and PEO 10 LiTFSI binder. Polysulfide concentration and area of spatial diffusion increased with cycling, indicating that some polysulfide dissolution is irreversible, leading to polysulfide shuttle. Fitting of the maps using standard sulfur and polysulfide XANES spectra indicated that upon subsequent discharge/charge cycles, the initial sulfur concentration was not fully recovered; polysulfides and lithium sulfide remained at the cathodes with higher order polysulfides as the primary species in the region of interest. Quantification of the polysulfide concentration across the electrolyte and electrode interfaces shows that the polysulfide concentration before the first discharge and after the third charge is constant within the electrolyte, but while cycling, a significant increase in polysulfides and a gradient toward the lithium metal anode forms. This chemically and spatially sensitive characterization and analysis provides a foundation for further operando spectromicroscopy of lithium-sulfur batteries. New "beyond lithium-ion" battery chemistries are essential to meet the increasing demand for long-lasting, high capacity energy storage in portable electronics and electric vehicles. Lithium-sulfur (Li-S) batteries are an attractive Li-ion alternative that provides large capacity (1672 mAh g −1 ) and energy density (2500 Wh kg −1 ) while also being low cost, earth-abundant, and lightweight.1-3 Li-S batteries have a unique chemistry that achieves high capacity via chemical transformation rather than Li intercalation. Elemental sulfur (S 8 ) is reduced through a series of soluble Li polysulfides (Li 2 S x , 2 ≤ x ≤ 8) to a final solid discharge product (Li 2 S), and the process is reversed upon charging. [4][5][6] However, Li-S suffers from unrealized theoretical capacity and rapid capacity fade due to loss processes that are not well-understood. 2,7 While many advances in electrode and electrolyte engineering have been made in an attempt mitigate these performance issues, 8-14 a gap remains in the mechanistic understanding of Li-S battery operation. Several mechanisms for reduced capacity and capacity fade have been proposed. Lithium polysulfides, which are necessary for operation, dissolve into the liquid electrolyte, remain dissolved, and "shuttle" between the electrodes rather than participating in the electrochemical reactions, decreasing the amount of active material available. 3,[15][16][17][18] Low sulfur utilization results in initially low capacity that then continues to decrease with subsequent cycles. [19][20][21] Batteries are spatiall...

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“…The TFY and TEY signals reflect sample information of probing depth up to several hundred nanometers and tens nanometers, respectively. 21 In contrast to XAS where the excitation energy is altered, in XES core electrons are excited at constant excitation energy and the emission is recorded (using a grating spectrometer wherein the intensity distribution as a function of photon energy) as core holes are re-populated by electrons in the occupied density of states. Following the decay route of valence electrons in the emission process, the detection depth of XES is hundred nanometers, as compared to few of nanometers in the case of XAS.…”

Section: Principles Of Synchrotron Spectroscopymentioning

confidence: 99%

X-ray spectroscopies studies of the 3d transition metal oxides and applications of photocatalysis

Kapilashrami

Chuang

et al. 2017

MRS Communications

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Abstract:Recent advances in synchrotron based X-ray spectroscopy enable materials scientists to emanate finger prints on important materials properties e.g. electronic, optical, structural and magnetic properties, in real time and under nearly real-world conditions. This characterization in combination with optimized materials synthesis routes and tailored morphological properties could contribute greatly to the advances in solid-state electronics and renewable energy technologies. In connection to this, such perspective reflects the current materials research in the space of emerging energy technologies, namely photocatalysis, with a focus on transition metal oxides (TMOs), mainly on the Fe 2 O 3 and TiO 2 based materials.

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X-ray Absorption Spectroscopy Characterization of a Li/S Cell

Cited by 34 publications

References 35 publications

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

Operando Spectromicroscopy of Sulfur Species in Lithium-Sulfur Batteries

X-ray spectroscopies studies of the 3d transition metal oxides and applications of photocatalysis

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