Advanced Lithium Ion Sulfur Battery Based on Spontaneous

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An Advanced Lithium Ion Sulfur Battery Based on Spontaneously Electrochemical Exfoliation/ Lithiation of Graphite in Non-aqueous Electrolytes Pengcheng Shi, Xin Zhou, Yong Wang, Xin Liang, Yi Sun, Sheng Cheng, Chunhua Chen, and Hongfa Xiang ACS Appl. Energy Mater., Just Accepted Manuscript • DOI: 10.1021/acsaem.9b00480 • Publication Date (Web): 02 May 2019 Downloaded from http://pubs.acs.org on May 3, 2019

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ACS Applied Energy Materials

An

Advanced

Lithium

Ion

Sulfur

Battery

Based

on

Spontaneously

Electrochemical Exfoliation/Lithiation of Graphite in Non-aqueous Electrolytes Pengcheng Shi,† Xin Zhou,† Yong Wang,† Xin Liang,† Yi Sun,† Sheng Cheng,† Chunhua Chen,‡ Hongfa Xiang†* †

School of Materials Science and Engineering, Hefei University of Technology, Hefei, Anhui

230009, China ‡ CAS

Key Laboratory of Materials for Energy Conversions, Department of Materials Science and

Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China

ABSTRACT An advanced lithium ion sulfur battery is constructed on the basement of spontaneous electrochemical exfoliation and lithiation of graphite in non-aqueous electrolytes, in which to produce a high-quality graphene matrix for the sulfur cathode and lithiated graphite for the anode, respectively. On one hand, the high quality graphene, obtained via spontaneously electrochemical exfoliation of graphite in propylene carbonate-based electrolyte, works as a matrix to improve the conductivity of sulfur and trap the polysulfides. On the other hand, the lithiated graphite anode, obtained by spontaneously electrochemical lithiation of graphite in ethylene carbonate-based electrolyte with 5 wt. % fluoroethylene carbonate additive, provides amply lithium ion sources and increases the safety coefficient of lithium ion sulfur battery. Meanwhile, the fluoroethylene carbonate additive can derive a LiF-rich solid electrolyte interphase on lithiated graphite anode, which can in turn mitigate the 1

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notorious “shuttle effect”. More attractively, the spontaneously electrochemical exfoliation and lithiation method can produce high quality graphene and lithiated graphite in large scale and without electric energy consumption. Therefore, this approach shows great potential for the configuration of an advanced lithium ion sulfur battery with enhanced safety and high energy density. KEYWORDS: Electrochemical exfoliation/lithiation, lithium sulfur batteries, Lithium ion sulfur batteries, shuttle effect, solid electrolyte interphase

INTRODUCTION The ever-growing market of electric vehicles (EVs) and hybrid electric vehicles (HEVs) has required both academic and industry to develop lithium (Li) ion batteries (LIBs) with high safety and high energy density. For instance, in 2009, IBM launched the “Battery 500” project at the aim of developing advanced batteries to support a target range of 500 mile per charge and a cycle life of 600 cycles for EVs.1, 2 To that aim, the development of alternative electrode materials with high capacity and long cycle life is of primary important.3,

4

Recently, sulfur (S), which is notable for its

ultrahigh theoretical specific capacity of 1675 mAh g-1, has been regarded as a promising cathode material. Additionally, S is natural abundant, nontoxic and low cost.5, 6 Therefore, it is highly desired to find a suitable anode for S cathode. Generally, the most desired anode for S cathode would of course be metallic Li regard to battery energy density.7 However, safety problems arising from the growth of Li dendrites, which may pierce through the separator and result in the internal short 2


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circuit, have long prevented the application of Li-S batteries.8 For these reason, lithium ion sulfur batteries (LISBs) that replace Li with other anode materials show an attractive perspective on improving the battery safety coefficient. Various alternative electrode materials such as Sn9, 10 and Si3, 11-14 have been employed to pair with S and assembled as LISBs. Unfortunately, huge volume expansion of these materials during cycling always result in the pulverization of electrodes, the loss of active Li+ and the continuous growth of solid electrolyte interphase (SEI). Consequently, capacities of the as-assembled LISBs decay rapidly.15, 16 Meanwhile, the complex synthetic routes also further prevented them from application. On the contrary, graphite seems to be a promising candidate as it has been successfully applied in state-of-the-art LIBs for decades due to its limited volume expansion and stable SEI. These features are also beneficial for enhancing the cycle life of LISBs.17-19 Therefore, it holds great promise to investigate the graphite-S full cells. In order to achieve high capacity and high energy density graphite-S full cells, the electrochemical performances of both the graphite anode and S cathode should also be optimized. For the S cathode, the main challenge is the poor electronic conductivity, significant volume expansion and the notorious “shuttle effect”.20-22 To tackle these issues, high-quality graphene has been proved to be a promising candidate because of its excellent conductivity, good mechanical flexibility and high specific surface area.23, 24 For the graphite anode, due to the lack of Li+, it must be pre-lithiated before assembled into LISBs. Meanwhile, the SEI layer formed on the pre-lithiated graphite is thick, which can not sufficiently constrain the “shuttle effect” 3



to a low level, consequently leads to a short cycle life and low coulombic efficiency (CE) of LISB. Therefore, in order to configure an advanced graphite-sulfur cells, it is still highly desired to develop an effective strategy to prepare high-quality graphene matrix and minimize the notorious “shuttle effect”. Recently, our group reported a non-electrified electrochemical method to produce high quality graphene.25 It is via directly contact graphite and Li in propylene carbonate (PC)-based electrolyte to form tremendous of Li||graphite micro-cells, which would then spontaneously exfoliate graphite into high quality graphene. After 8 h reaction, the graphite is obviously exfoliated according to our previous investigation.25 Herein, as shown in Figure 1, we further develop this non-electrified electrochemical method to prepare high quality graphene matrix and lithiated graphite (LG) anode for the configuration of an advanced LISB. The high quality graphene, obtained via spontaneous electrochemical exfoliation of graphite in PC-based electrolyte, worked as a host matrix for S and trap the polysulfides. Meanwhile, the LG electrode, obtained via spontaneous electrochemical lithiation of graphite in ethylene carbonate (EC)-based electrolyte with 5 wt. % fluoroethylene carbonate (FEC) additive, severed as anode to provide amply Li+ sources for LISB. By the way, the FEC additive can derive a LiF-rich SEI on LG anode, which can in turn reduce the notorious “shuttle effect”. More attractively, the LG anode also has safety advantage over conventional metallic Li. Last but not least, these kind spontaneously electrochemical reactions between graphite and Li can produce high quality graphene and LG in large scale and without consumption of electric energy. Therefore this 4


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method shows great potential for the configuration of an advanced LISB with high safety. EXPERIMENTAL SECTION Material Synthesizes Actually, the electrochemical exfoliation and lithiation of graphite are tightly associated with the SEI film formation abilities of electrolytes. For spontaneously electrochemical exfoliation, the electrolyte is 1.0 M LiPF6/PC.25 The collected graphene is further used to prepare S@graphene composite. Typically, 0.075 g graphene, 1.2 g Na2S2O3 and 0.5 mL Trixon-100 was dissolved in 500 mL deionized H2O under magnetic stirring. After 1 h, 60 mL HCl (0.5 M) was slowly dropped. The product was then filtered and washed with deionized H2O. For spontaneously electrochemical lithiation, the electrolyte is 1.0 M LiPF6 in EC, ethyl methyl carbonate (EMC) (4:6 by weight ratio) and 5 wt. % FEC. Typically, graphite electrode is directly contact with Li in the electrolyte to obtain a LG electrode. In order to form a good SEI film on LG electrode, the lithiation process takes for 5 h. The graphite electrode (the mass loading of graphite is controlled at ~3.4 mg) consists of 85% MCMB, 5% KS-6 (conductive carbon additive, obtained from TIMCAL), 5% acetylene black and 5% poly(vinylidene fluoride) (PVDF). Additionally, both the exfoliation and lithiation procedures were carried out in an argon-filled glove box with both O2 and H2O contents controlled below 0.1 ppm. Electrochemical Measurements The S@graphene cathode was made by mixing 70% S@graphene composite, 5



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20% ketjen black and 10% PVDF in N-methyl-2-pyrrolidone (NMP) solution; after ball milling for 30 min, it was then casted on Al foil. The electrode was then punched into disks with diameters of 10 mm after vacuum drying. The mass loading of S on each disk is controlled at about 0.8 mg cm-2. The S@graphene cathode and LG anode is further employed to construct the LISB (Coin 2032 type). The separator is Celgard 2400

polypropylene

membrane

while

the

electrolyte

is

1.0

M

lithium

bis(trifluoromethane sulfonimide) (LiN(SO2CF3)2, LiTFSI) in the mixture solvents of 1,3-dioxolane (DOL) and dimethyl ether (DME) (1:1 by volume ratio) with 2 wt.% LiNO3. To standard the testing, the electrolyte content is 80 µL per mg S in each cell. The LISB were cycled between 1.8 and 2.8 V. For comparison, conventional Li-S batteries on the basement of S@graphene cathode and metallic Li anode has also been assembled and tested in the same way. The capacities of both batteries are calculated on the basement of S loading content. Characterization Electrochemical impedance spectra (EIS) were performed on a CHI604D workstation, with a voltage perturbation of 10 mV and a frequency range of 0.1-105 Hz. X-ray diffraction (XRD, Cu Kα) was collected on X’ Pert PRO MPD instrument. The morphology and energy dispersive spectroscopy (EDS) mapping was obtained by scanning electron microscopy (SEM, Zeiss) and transmission electron microscopy (TEM, JEM-2100F), respectively. X-ray photoelectron spectroscopy (XPS) of the SEI layer is analyzed by America Thermo ESCALAB 250 instrument. Thermo gravimetric (TG) analysis was performed in N2 atmosphere with a heating rate of 5 °C 6


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per min from 25 to 800 °C.

RESULTS AND DISCUSSION The key point for building an advanced battery is to successfully synthesis a stable and high capacity cathode as well as a high safety anode. In this work, we demonstrate the configuration of an advanced LISB by using S@graphene cathode and LG anode which was prepared on the basis of spontaneously electrochemical reactions between graphite and Li in non-aqueous electrolytes. Additionally, materials for the LISB are easy available, low cost and the approach is facile and economic. Firstly, high-quality graphene (shown in Figure S1), obtained via spontaneously electrochemical exfoliation of graphite in PC-based electrolyte, was used to prepare S@graphene cathode of LISB. Characteristics of the as-prepared S@graphene composite were first investigated by XRD. As shown in Figure 2a, the diffraction peaks of the S@graphene composite coincide well with the standard XRD pattern of S (JCPDS 00-008-0247),26 suggesting S has been successfully loaded on graphene. Notably, no peaks of graphite were observed, indicating the graphene are still remained in a substantially exfoliated state. TG measurement is further used to identify the loading of S content of the S@graphene composite. As shown in Figure 2b, the weight loss within the temperature range between 150-250 °C of the TG curves indicates the S content is 69.5%. Such high loading of S content is satisfying for practical applications. The morphology and S distribution of S@graphene composite were further 7



investigated by SEM and TEM. As shown in Figure 3a, S was wrapped efficiently by graphene sheets. Therefore, the graphene is helpful for preventing the dissolution of polysulfides and accommodating the volume expansion of S according to previous studies.27 The TEM image and EDS mapping in Figure 3b-d further revealed that the homogenously distribution of S on graphene. Hence, the graphene matrix can provide sufficient active sites for S. Benefit from these advantages, the S@graphene composite would be favorable for achieving excellent electrochemical performances discussed follow. As discussed above, the low conductivity of S and dissolution of polysulfides is effectively solved by graphene wrapping. Another critical issue of Li-S battery is the safety problems arising from the growth of Li dendrites as well as high intrinsically chemical reactivity of metallic Li in common used electrolytes. For this reason, an alternative configuration of LG anode, which was prepared by spontaneously electrochemical lithiation of graphite in EC-based electrolyte, was used as anodes for LISB. As shown in the insert image in Figure 4, the color of the graphite turned gold after lithiation, suggesting Li+ has been successfully intercalated into graphite. The lithiation of graphite can further be proved by XRD.28 In Figure 4, the peaks between 20~25o are ascribed to the Li-graphite intercalation compound (stage 1 of LiC6 and stage 2 of LiC12). Additionally, the CV curve in Figure S2 also indicated Li+ has been successfully intercalated into graphite. Therefore, the LG anode has a high lithiation degree and can supply ample Li+ sources for LISB. Generally, the state-of-the-art electrolytes for Li-S batteries are based on ether 8


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solvents (e. g.; DOL, DME). Unfortunately, these ether-based electrolytes are not suitable for graphite electrode since the co-intercalation of Li+-solvent complexes would exfoliate graphite and consequently lead to the breakdown of graphite electrode.17 Nevertheless, the exfoliation can be suppressed by construct a stable SEI. Hence, it is essential to investigate the compatibility between the LG electrode and the 1.0 M LiTFSI/DOL-DME electrolyte. In Figure S3a-b, the initial charge curves of both cells in the electrolyte without and with 2% LiNO3 coincide well. Nevertheless, the corresponding discharge curves are different. The cell in the electrolyte without LiNO3 shows a plateau at ~0.5 V, suggesting the exfoliation of graphite. By contrast, when 2% LiNO3 is adopted, the initial discharge curve of LG||Li cells shows distinct Li+ intercalation plateau. Therefore, LiNO3 can construct a stable SEI on LG electrode for reversible Li+ intercalation/de-intercalation. Meanwhile, the LG||Li cell in the electrolyte with 2% LiNO3 shows an initial charge capacity of 340 mAh g-1 and a high coulombic efficiency (CE) of 97%. Notably, the capacity and CE remains at 340 mAh g-1 and 100% in Figure 5a, respectively. After 50 cycles, the resistance is only 5 Ω in Figure 5b, indicating the structure of LG electrode remains stable in the electrolyte containing LiNO3. Therefore, the LG electrode yields a good compatibility with ether-based electrolyte containing LiNO3 and can preserve sufficient Li+ for S@graphene cathode, which finally guarantees the possibility and the potential advantages of replacing Li by LG to construct an LISB with high safety. Based on the aforementioned results, the S@graphene cathode and LG anode are employed to construct an LISB. The electrochemical performances of LISB are 9



shown in Figure 6. For comparison, conventional Li-S batteries on the basement of S@graphene cathode has also been assembled and tested in the same way. In Figure 6a, both batteries exhibit the typical voltage profiles of two discharge plateaus and a charge plateau. Nevertheless, it is worth noting that the plateaus of LISB are ~0.1 V lower than that of Li-S batteries. This is primarily because graphite has a higher Li+ intercalation/de-intercalation potential of ~0.1 V than that of Li. Typically, the discharge plateaus at 2.1~2.3 V and 1.9~2.1 V corresponds to the reduction of S to long-chain polysulfides (Li2Sn, 4≤n≤8) and then to short-chain polysulfide (Li2Sn, n ≤2). The charge plateau at 2.3 V is related to the oxidation of short-chain polysulfide to S.29 dQ/dV curves was further employed to understand the electrochemical process of LISB. In Figure 6b, the cathodic peaks (2.0~2.3 V) of both cells correspond to the multiple step reduction processes of S into short-chain polysulfide whereas the anodic peaks at 2.15 V and 2.3 V are assigned to the conversion of short-chain polysulfide to S for LISB and Li-S batteries, respectively. These peaks coincide well with the plateaus of 1st curves in Figure 6a. Nevertheless, the LISB appears a new anodic peak at ~2.3 V, which may relate to the intercalation of Li+ into graphite. Therefore Li+ can reversibly intercalate/de-intercalation from LG electrode in practical LISB. The cycling performance and CE of each cell is further compared in Figure 6c. The initial discharge capacity of the LISB and Li-S cell is 1193 and 1291 mAh g-1, respectively. The higher discharge capacity of Li-S cell is mainly because metallic Li can supply more Li+ for S@graphene cathode as compare with that of LG anode. After 130 cycles, the discharge capacity of LISB is 714 mAh g-1 whereas that of Li-S battery is 10


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603 mAh g-1. The average CE of both batteries is about 99%. Additionally, the polarization of LISB is relatively lower as compared with that of the Li-S battery, as shown in Figure S4. The enhanced electrochemical performance can be attributed to the SEI on the surface of LG, which is more effective in suppressing the “shuttle effect”. Table S1 shows a comparison of the configuration and cycling performances of various LISBs.3, 12, 30-34 Obviously, the performance of this battery is comparable with those of state-of-the-art LISBs. Nevertheless, only this LISB is prepared from spontaneously electrochemical exfoliation and lithiation of graphite by tuning the electrolytes. Figure 6d shows the EIS curves of batteries after 130 cycles. Obviously, the RSEI of LISB (56 Ω) is much smaller than that of Li-S batteries (95 Ω), suggesting the SEI on LG is more conductive for Li+ than the SEI layer on Li anode.35 Moreover, the low-frequency slope angle of LISB is also larger than that of Li-S batteries, indicating that the LG electrode has a better Li+ transfer kinetics than Li.36 The rate performance of the LISB and Li-S batteries is further compared. As shown in Figure S5, the advanced LISB doesn’t compromise the rate performance as compared with that of the Li-S batteries. At 0.2 C, the LISB can deliver a capacity of 842 mAh g-1. When the current density increased to 0.5 C and 1 C, the discharge capacity reduced to 728 mAh g-1 and 232 mAh g-1, respectively. Nevertheless, when the current density set back to 0.2 C, the discharge capacity can return back to ~ 750 mAh g-1. Therefore, the LG electrode is a promising candidate for replacing Li to construct LISB. The surface morphology of both anodes after cycling is further analyzed by SEM. Before the measurements, the electrodes were immersed in DME for 20 h and then 11



rinsed with fresh DME several times to remove Li salts. In Figure 7a, a large amount of dendrites were observed on the surface of Li anode. On the contrary, the LG electrode is dendrite-free and covered by a dense and compact SEI layer in Figure 7b. Therefore, the LG electrode has a higher safety coefficient than conventional Li anode. XPS was further carried out to accurately analyze the chemical composition of the SEI films on various anodes. The differences of the SEI layer can be obviously seen in the wide XPS scans and the corresponding element ratios in Figure S6. In Li 1s spectra, both samples contain a peak of LiNxOy (55.8 eV) in Figure 8a, which originated from the reduction of LiNO3.37 Additionally, the peaks located at 55.3 eV are species of LiF, Li2CO3, ROLi, ROCO2Li.38, 39 The difference of the SEI layer can also be proved by F 1s spectra in Figure 8b. Notably, the peak of -CF3 is ascribed to the residual LiTFSI. Compare with metallic Li anode, the LG electrode shows an intensity peak of LiF (684.9 eV),39 which mainly originated from the reduction of FEC during electrochemical lithiation process. LiF has been proved to be good for improving the properties of SEI and preventing the growth of Li dendrites. Therefore, the LG electrode is good for reducing the “shuttle effect” and increasing battery safety coefficient, which in turn improving the performances of LISB. In C 1s spectra in Figure 8c, the peaks located at 288.9 eV and 285.1 eV are ascribed to Li2CO3 and ROCO2Li, respectively.37 The peaks located at 284.8 eV and 290.0 eV are corresponding to element of C and PVDF in LG anode.40 In O 1s spectra in Figure 8d, the peak located at 535.6 eV is LiNxOy, while peaks located at 531.4 and 531.7 eV is 12


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consistent with the presence of C-O and C=O containing species.41

CONCLUSION An advanced LISB is constructed by using S@graphene cathode and LG anode, which is prepared on the basement of spontaneously electrochemical exfoliation and lithiation of graphite in non-aqueous electrolytes. On one hand, graphene, obtained from electrochemical exfoliation of graphite in PC-based electrolyte, worked as a conducting matrix to improve the conductivity of S and trapped polysulfides. On the other hand, the LG electrode, obtained by electrochemical lithiation of graphite in EC-based electrolyte with FEC additive, worked as the anode to provide amply Li+ sources and increases the safety of LISB. Meanwhile, the LiF-rich SEI layer derived from FEC on LG anode can mitigate the “shuttle effect” and improve the CE of LISB. Last but not least, this spontaneously electrochemical exfoliation and lithiation method can produce high quality graphene and LG in large scale and without electric energy consumption. Therefore, this approach shows great potential for the configuration of an advanced LISB with enhanced safety and high energy density.

ASSOCIATED CONTENT Supporting Information: TEM image of the exfoliated graphene. CV curve of LG||Li cell. Initial charge and discharge curves of the LG||Li cells in 1.0 M LiTFSI/DOL-DME electrolyte without and with 2% LiNO3. Charge and discharge curves of LISB and Li-S batteries. Rate performance of the LISB and Li-S batteries. 13



Wide XPS scans and the corresponding element content. Electrochemical performance of various LISBs. The Supporting Information is available free of charge on the ACS Publications website.

AUTHOR INFORMATION: Corresponding author: Tel.: +86-551-62901457; E-mail: [email protected] Notes: The authors declare no competing financial interest.

ACKNOWLEDGEMENTS This study was supported by National Science Foundation of China (Grant Nos. 51372060, 21676067, and 21606065), Opening Project of CAS Key Laboratory of Materials for Energy Conversion (KF2016005), Anhui Provincial Natural Science Foundation (Grant No. 1708085QE98), and the Fundamental Research Funds for the Central Universities (Grant No. JZ2017HGTB0198, JZ2017YYPY0253).

REFERENCES (1) Cheng, X. -B.; Zhang, Q. Dendrite-Free Lithium Metal Anodes: Stable Solid Electrolyte Interphases for High-Efficiency Batteries. J. Mater. Chem. A 2015, 3, 7207-7209. (2) Luo, Z. -K.; Liang, C. S.; Wang, F.; Xu, Y. -H.; Chen, J.; Liu, D.; Sun, H. -Y.; 14


Page 14 of 26

Page 15 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Yang, H.; Fan, X. P. Optimizing Main Materials for A Lithium-Air Battery of High Cycle Life. Adv. Funct. Mater. 2014, 24, 2101-2105. (3) Shen, C. F.; Ge, M. Y.; Zhang, A. Y.; Fang, X.; Liu, Y. H.; Rong, J. P.; Zhou, C. W. Silicon(Lithiated)-Sulfur Full Cells with Porous Silicon Anode Shielded by Nafion Against Polysulfides to Achieve High Capacity and Energy Density. Nano Energy 2016, 19, 68-77. (4) Ouyang, T.; Ye, Y. Q.; Wu, C. Y.; Xiao, K.; Liu, Z. P. Heterostructures Composed of N-Doped Carbon Nanotubes Encapsulating Cobalt and b-Mo2C Nanoparticles as Bifunctional Electrodes for Water Splitting. Angew. Chem. Int. Ed. 2019, 58, 1-7. (5) Liang, X.; Zhang, M. G.; Kaiser, M. R.; Gao, X. W.; Konstantinov, K.; Tandiono, R.; Wang, Z. X.; Liu, H. -K.; Dou, S. X.; Wang, J. Z. Split-Half-Tubular Polypyrrole@Sulfur@Polypyrrole Composite with A Novel Three-Layer-3D Structure as Cathode for Lithium/Sulfur Batteries. Nano energy 2015, 11, 587-599. (6) Zhou, G. M.; Li, L.; Ma, C. Q.; Wang, S. G.; Shi, Y.; Koratkar, N.; Ren, W. C.; Li. F.; Cheng, H. -M. A Graphene Foam Electrode with High Sulfur Loading for Flexible and High Energy Li-S Batteries. Nano Energy 2015, 11, 356-365. (7) Cao, R. G.; Xu, W.; Lv, D. P.; Xiao, J.; Zhang, J. -G. Anodes for Rechargeable Lithium-Sulfur Battery. Adv. Energy Mater. 2015, 5, 513-537. (8) Xu, W.; Wang, J. L.; Ding, F.; Chen, X. L.; Nasybulin, E.; Zhang, Y. H.; Zhang, J. -G. Lithium Metal Anodes for Rechargeable Batteries. Energ. Environ. Sci. 2014, 7, 513-537. (9) Hassoun, J.; Scrosati, B. A High-Performance Polymer Tin Sulfur Lithium Ion 15



Battery. Angew. Chem., Int. Ed. 2010, 49, 2371-2374. (10) Hassoun, J.; Sun, Y. -K.; Scrosati, B. Rechargeable Lithium Sulfide Electrode for A Polymer Tin/Sulfur Lithium-Ion Battery. J. Power Sources 2011, 196, 343-348. (11) Yan, Y.; Yin, Y. X.; Xin, S.; Su, J.; Guo, Y. G.; Wan, L. J. High-Safety Lithium-Sulfur Battery with Prelithiated Si/C Anode and Ionic Liquid Electrolyte. Electrochim. Acta 2013, 91, 58-61. (12) Hassoun, J.; Kim, J.; Lee, D. J.; Jung, H. -G.; Lee, S. -M.; Sun, Y. -K.; Scrosati, B. A Contribution to the Progress of High Energy Batteries: A Metal-Free, Lithium-Ion, Silicon-Sulfur Battery. J. Power Sources 2012, 202, 308-313. (13) Brückner, J.; Thieme, S.; Böttger-Hiller, F.; Bauer, I.; Grossmann, H. T.; Strubel, P.; Althues, H.; Stefan, S.; Stefan K. Carbon-Based Anodes for Lithium Sulfur Full Cells with High Cycle Stability. Adv. Funct. Mater. 2014, 24, 1284-1289. (14) Li, B.; Li, S. M.; Xu, J. J.; Yang, S. B. A New Configured Lithiated Silicon-Sulfur Battery Built on 3D Graphene with Superior Electrochemical Performances. Energy Environ. Sci. 2016, 9, 2025-2030. (15) Jeschull, F.; Brandell, D.; Edström, K.; Lacey, M. J. A Stable Graphite Negative Electrode for the Lithium-Sulfur Battery. Chem. Commun. 2015, 51, 17100-17103. (16) Sun, W.; Hu, R. Z.; Liu, H.; Zeng, M. Q.; Yang, L. C.; Wang, H. H.; Zhu, M. Embedding Nano-Silicon in Graphene Nanosheets by Plasma Assisted Milling for High Capacity Anode Materials in Lithium Ion Batteries. J. Power Sources 2014, 268, 610-618. (17) Bhargav, A.; Wu, M.; Fu, Y. Z. A Graphite-Polysulfide Full Cell with 16


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DME-Based Electrolyte. J. Electrochem. Soc. 2016, 163, A1543-A1549. (18) Agostini, M.; Scrosati, B.; Hassoun, J. An Advanced Lithium-Ion Sulfur Battery for High Energy Storage. Adv. Energy Mater. 2015, 5, 1500481-1500486. (19) Li, Z.; Zhang, S. G.; Terada, S. S.; Ma, X. F.; Ikeda, K. H.; Kamei, Y.; Zhang, C.; Dokko, K.; Watanabe, M. Promising Cell Configuration for Next-Generation Energy Storage: Li2S/graphite Battery Enabled by A Solvate Ionic Liquid Electrolyte. ACS Appl. Mater. Interfaces 2016, 8, 16053-16062. (20) Song, R. S.; Fang, R. P.; Wen, L.; Shi, Y.; Wang, S. G.; Li, F. A Trilayer Separator with Dual Function for High Performance Lithium-Sulfur Batteries. J. Power Sources 2016, 301, 179-186. (21) Yu, M. P.; Li, R.; Wu, M. M.; Shi, G. Q. Graphene Materials for Lithium-Sulfur Batteries. Energy Storage Mater. 2015, 1, 51-73. (22) Kaiser, M. R.; Liang, X.; Konstantinov, K.; Liu, H. -K.; Dou, S. -X.; Wang, J. -Z. A Facile Synthesis of High-Surface-Area Sulfur-Carbon Composites for Li/S Batteries. Chem. Eur. J. 2015, 21, 10061-10069. (23) Shi, P. C.; Wang, Y.; Liang, X.; Sun, Y.; Cheng, S.; Chen, C. H.; Xiang, H. F. Simultaneously Exfoliated Boron-Doped Graphene Sheets to Encapsulate Sulfur for Applications in Lithium-Sulfur Batteries. ACS Sustainable Chem. Eng. 2018, 6, 9661-9670. (24) Tang, C.; Li, B. -Q.; Zhang, Q.; Zhu, L.; Wang, H. -F.; Shi, J. -L.; Wei, F. CaO-Templated Growth of Hierarchical Porous Graphene for High-Power Lithium-Sulfur Battery Applications. Adv. Energy Mater. 2015, 26, 577-585. 17



Page 18 of 26

(25) Shi, P. C.; Guo, J. P.; Liang, X.; Cheng, S.; Zheng, H.; Wang, Y.; Chen, C. H.; Xiang, H. F. Large-Scale Production of High-Quality Graphene Sheets by A Non-Electrified Electrochemical Exfoliation Method. Carbon, 2018, 126, 507-513. (26) Cao, Y.; Li, X. L.; Zheng, M. S.; Yang, M. P.; Yang, X. L.; Dong, Q. F. Ultra-High Rates and Reversible Capacity of Li-S Battery with A Nitrogen-Doping Conductive Lewis Base Matrix. Electrochim. Acta 2016, 192, 467-474. (27) Wang, H. L.; Yang, Y.; Liang, Y. Y.; Robinson, J. T.; Li, Y. G.; Jackson, A.; Cui, Y.; Dai, H. J. Graphene-Wrapped Sulfur Particles as A Rechargeable Lithium-Sulfur Battery Cathode Material with High Capacity and Cycling Stability. Nano Lett. 2011, 11, 2644-2647. (28) Yamada, Y.; Usui, K. J.; Chiang, C. H.; Kikuchi, K.; Furukawa, K.; Yamada, A. General

Observation

Ethylene-Carbonate-Free

of

Lithium

Superconcentrated

Intercalation Electrolytes.

into ACS

Graphite Appl.

in

Mater.

Interfaces 2014, 6, 10892-10899. (29) Cheng, X. B.; Huang, J. Q.; Peng, H. J.; Nie, J. Q.; Liu, X. Y.; Zhang, Q.; Wei, F. Polysulfide Shuttle Control: Towards A Lithium-Sulfur Battery With Superior Capacity Performance Up to 1000 cycles By Matching the Sulfur/Electrolyte Loading. J. Power Sources 2014, 253, 263-268. (30) Pu, X. B.; Yang, G.; Yu, C. Safe and Reliable Operation of Sulfur Batteries with Lithiated Silicon. Nano Energy 2014, 9, 318-324. (31) Shi, L.; Liu, Y. G.; Wang, W. K.; Wang, A. B.; Jin, Z. Q.; Wu, F.; Yang, Y. S. High-safety Lithium-ion Sulfur Battery with Sulfurized Polyacrylonitrile Cathode, 18


Page 19 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Prelithiated SiOx/C anode and Carbonate-based Electrolyte. J. Alloy. Compd. 2017, 723, 974-982. (32) Liu, M.; Zhou, D.; Jiang, H.R.; Ren, Y. X.; Kang, F. Y.; Zhao, T. S. A Highly-safe Lithium-ion Sulfur Polymer Battery with SnO2 anode and Acrylate-based Gel Polymer electrolyte. Nano Energy 2016, 28, 97-105. (33) Lv, D. P.; Yan, P. F.; Shao, Y. Y.; Li, Q. Y.; Ferrara, S.; Pan, H. L.; Graff, G. L.; Polzin, B.; Wang, C. M.; Zhang, J. -G.; Liu, J.; Xiao, L. High Performance Li-ion Sulfur Batteries Enabled by Intercalation Chemistry. Chem. Commun. 2015, 51, 13454-13457. (34) Weinbergera, M.; Wohlfahrt-Mehrensa, M. Novel Strategies Towards the Realization of Larger Lithium Sulfur/Silicon Pouch Cells. Electrochim. Acta 2016, 191, 124–132 (35) Xiang, H. F.; Shi, P. C.; Bhattacharya, P.; Chen, X. L.; Mei, D. H.; Bowden, M. E.; Zheng, J. M.; Zhang, J. -G.; Xu, W. Enhanced Charging Capability of Lithium Metal Batteries Based on Lithium Bis(trifluoromethanesulfonyl)imide-Lithium Bis(oxalato)borate Dual-Salt Electrolytes. J. Power Sources 2016, 318, 170-177. (36) Xiao, S.; Liu, S. H.; Zhang, J. Q.; Wang, Y. Polyurethane-Derived N-doped Porous Carbon with Interconnected Sheet-Like Structure as Polysulfide Reservoir for Lithium-Sulfur batteries. J. Power Sources 2015, 293, 119-126. (37) Xiong, S. Z.; Xie, K.; Diao, Y.; Hong, X. B. Characterization of the Solid Electrolyte Interphase on Lithium Anode for Preventing the Shuttle Mechanism in Lithium-Sulfur Batteries. J. Power Sources 2014, 246, 840-845. 19



(38) Diao, Y.; Xie, K.; Xiong, S. Z.; Hong, X. B. Insights into Li-S Battery Cathode Capacity Fading Mechanisms: Irreversible Oxidation of Active Mass During Cycling. J. Electrochem. Soc. 2012, 159, A1816-A1821. (39) Shi, P. C.; Lin, M.; Zheng, H.; He, X. D.; Xue, Z. M.; Xiang, H. F.; Chen, C. H. Effect of Propylene Carbonate-Li+ Solvation Structures on Graphite Exfoliation And Its Application in Li-ion batteries. Electrochim. Acta 2017, 247, 12-18. (40) Yang, L. J.; Cheng, X. Q.; Ma, Y. L. Lou, S. F.; Cui, Y. Z.; Guan, T.; Yin, G. P. Changing of SEI Film and Electrochemical Properties about MCMB Electrodes during Long-term Charge/discharge Cycles. J. Electrochem. Soc. 2013, 160, A2093-A2099. (41) Zhang, Q. B.; Liao, J.; Liao, M.; Dai, J. Y.; Ge H. L.; Duan, T.; Yao, W. T. One-dimensional Fe7S8@C Nanorods as Anode Materials for High-rate and Long-life Lithium-ion batteries. Appl. Surf. Sci. 2019, 473, 799-806.

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Figure captions

Figure 1. Schematic illustration of the configuration of LISB.

Figure 2. (a) XRD of the S@graphene composite. (b) TG curve of the S@graphene composite.

Figure 3. Characteristics of S@graphene composite (a) SEM, (b) TEM, EDS mapping for the elements of: (c) C, and (d) S.

Figure 4. XRD pattern and optical image (insert) of the LG electrode.

Figure

5.

Electrochemical

performances

of

the

LG||Li

cell

in

1.0

M

LiTFSI/DOL-DME (1:1, v/v) with 2% LiNO3 (a) Cycling performance and the corresponding coulombic efficiency at 0.2 C. (b) EIS curves after 50 cycles.

Figure 6. Electrochemical performances of the LISB and Li-S batteries. (a) Initial charge-discharge curves at 0.1 C, (b) corresponding dQ/dV curves, (c) cycling performance and CE at 0.2 C, (d) EIS curves after 130 cycles.

Figure 7. SEM images of (a) Li and (b) LG electrode after cycling

21



Figure 8. XPS spectra of various anodes after 130 cycles. (a) Li 1s; (b) F 1s; (c) C 1s; (d) O 1s.

Figure 1. Schematic illustration of the configuration of LISB.

(b)

(222)

(a)

S@Graphene

100 80

TG (%)

(026) (040)

Intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 26

40

20

30 40 50 2Theta (degree)

60

69.5%

20

JCPDS 00-008-0247

10

60

0

70

0

100

200

300 400 500 600 Temperature (oC)

700

800

Figure 2. (a) XRD of the S@graphene composite. (b) TG curve of the S@graphene composite.

22


Page 23 of 26

Figure 3. Characteristics of S@graphene composite (a) SEM, (b) TEM, EDS mapping for the elements of: (c) C, and (d) S.

LG 

Intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Stage 2 Li-GIC(LiC12)

Cu

Stage 1 Li-GIC(LiC6) 



10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

2 Theta (degree)

Figure 4. XRD pattern and optical image (insert) of the LG electrode.

23



360

80 320

60

280

40

240 200

Figure

20

0

5

5.

(b) 30 25 -Z'' (ohm)

100

Coulombic efficiency (%)

-1

Capacity (mAh g )

(a) 400

20 15 10 5 0

0 10 15 20 25 30 35 40 45 50 Cycle number

Electrochemical

0

performances

5

of

10

the

15 Z' (ohm)

LG||Li

20

cell

25

in

30

1.0

M

LiTFSI/DOL-DME (1:1, v/v) with LiNO3 (a) Cycling performance and the corresponding coulombic efficiency at 0.2 C. (b) EIS curves after 50 cycles.

(a)3.0

(b) 15000

Li LG

-1

dQ/dV (mAh g V )

2.4 2.2

-15000 -20000

1.8

-25000

300 600 900 -1 Capacity (mAh g )

1.8

60

900 600

40

300

20

0

20

40

60 80 Cycle number

100

120

Coulombic Efficiency (%)

Li LG 80

1200

2.0

120

100 1500

-1

1200

2.2 2.4 Voltage (V)

2.8

Li LG

100 80 60 40 20

72o

0

0

2.6

(d)

-Z'' (ohm)

0

1800

0

0 -5000

-10000

2.0

(c)

5000

-1

Voltage (V)

2.6

1.6

Li LG

10000

2.8

Capacity (mAh g )

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 26

0

20

40

60 Z' (ohm)

60o 80

100

120

Figure 6. Electrochemical performances of the LISB and Li-S batteries. (a) Initial charge-discharge curves at 0.1C, (b) corresponding dQ/dV curves, (c) cycling performance and CE at 0.2C, (d) EIS curves after 130 cycles.

24


Page 25 of 26

Figure 7. SEM images of (a) Li and (b) LG electrode after cycling Li 1s LiF, Li 2CO3, ROLi, ROCO2Li

52

(c)

(b)

Li LG

54

C 1s

56

Intensity (a.u.)

LiNx Oy

Intensity (a.u.)

(a)

58

PVDF

F 1s

Li LG

Li 2CO3 C-C

PVDF

690

(d)

688

686

682

O 1s

680

678 Li LG

C-O

Intensity(a.u.)

C=O

ROCO2Li

294

684

Binding energy (eV)

CF3

296

Li LG

Li-F

CF3

60

Binding energy (eV)

Intensity (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


292

290

288

286

284

282

280

540

LiNx Oy

538

536

534

532

530

528

Binding energy (eV)

Binding energy (eV)

Figure 8. XPS spectra of various anodes after 130 cycles. (a) Li 1s; (b) F 1s; (c) C 1s; (d) O 1s.

25



Table of Contents

Spontaneously electrochemical exfoliation and lithiation of graphite in non-aqueous electrolytes for the configuration of an advanced lithium ion sulfur battery.

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Advanced Lithium Ion Sulfur Battery Based on Spontaneous

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