Double-Confined Sulfur Inside Compressed Nickel Foam and Pencil

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Double Confined Sulfur inside Compressed Nickel Foam and Pencil-Plating Graphite for Lithium-Sulfur Battery Xuefeng Li, Shimou Chen, Juntian Fan, Zhongliang Hu, and Suo-Jiang Zhang Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.7b04338 • Publication Date (Web): 27 Mar 2018 Downloaded from http://pubs.acs.org on March 27, 2018

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Industrial & Engineering Chemistry Research

Double Confined Sulfur inside Compressed Nickel Foam and Pencil-Plating Graphite for Lithium-Sulfur Battery Xuefeng Li†,‡ Shimou Chen ‡*, Juntian Fan‡, Zhongliang Hu†*, and Suojiang Zhang‡* †

College of Metallurgic Engineering, Hunan University of Technology,Zhuzhou

412007, China. ‡

Key Laboratory of Green Process Engineering, State Key Laboratory of Multiphase

Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Zhongguancun, Haidian District, Beijing, 100190, China

KEYWORDS: Lithium-Sulfur,

double

confined,

binder-free

ACS Paragon Plus Environment

high-performance

cathode,

Industrial & Engineering Chemistry Research 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

ABSTRACT: In this work, the sulfur confined inside the interpenetrating network of compressed nickel foam we prepared and their application as high-performance S cathode for lithium sulfur batteries were investigated. The double confine by Ni foam and pencil-plating graphite makes the cathode high-performance. The mechanical physical method was applied to prepare the S cathode at room temperature without using binder and conductive additives. The sulfur mass loading was controlled between 0.42 and 3.32 mg/cm2 in the cathode piece. The optimized cathode of 0.42 mg/cm2 S on Ni foam displayed high initial discharge capacity (1412mAh/g at 1 C), long cycle stability (1014mAh/g after 100 cycles at 1C, S 1.05 mg/m2) and high rate capability (495mAh/g at 2C, S 1.15 mg/cm2). This rapid, simple, one-step cathode preparation method may pave a new practical way for mass production of high-performances S cathode materials in lithium sulfur battery technology.


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Introduction As the increasing concern on the reduction of nonrenewable fossil fuels and the consequences of serious environmental pollution, more and more renewable and clean energy sources have been developed to replace the traditional energy materials[1]. Battery systems storing surplus electricity generated by renewable sources have attracted considerable attention during the past decade[2, 3]. So far, lithium–ion batteries have successfully enabled the widespread use of portable electronic devices and power tools, such as lithium-sulfur batteries. It has started to accelerate development[2,

3, 5-7]

. Sulfur is also a cheap and environmentally friendly material

which is beneficial for large-scale stationary energy storage. In addition, sulfur undergoes a two electron redox reaction with lithium and offers an extremely high theoretical specific capacity of 1675 mAh/g and a high energy density of 2600 Wh/kg[8, 9]. However, there are also some problems in lithium sulfur batteries. Several challenges are associated with sulfur cathode materials which still persist and may prevent their practical applications, including low electronic and ionic conductivities of solid sulfur species (S, Li2S, and Li2S2), that limit specific capacity and rate capability[10-12], dissolution of polysulfide into electrolyte and subsequent redox shuttling leading to low Coulombic efficiency, rapid capacity fading, high self-discharge rates[13-15]. Furthermore, the large volume changes of sulfur during charging and discharging reactions may lead to induce mechanical damage to the electrode[16, 17]. Therefore, sulfur cathode materials are usually composed of carbon matrix and sulfur species to overcome these drawbacks. However, problem still exist



in these carbon-based cathodes with different loading amount of S. First, sulfur content in carbon-based nanostructured composite is usually not more than 60-70 wt % which results in low capacity calculated by the entire mass of the cathode. Second, when the cathode is prepared, the use of conductive additives and binders further reduces the sulfur ratio of the cathode. The binder will also result in the electrode polarization and the slow dynamics particularly at high rate charge/discharge. Third, the collapse of electrode is a vital problem that would lead to fast decay of Li-S batteries. Therefore, it is important to prepare a cathode with high sulfur content and meanwhile maintain high integrity during the cycling for the elimination of the electrode collapse[18-20]. These problems are mainly related to the preparation of the cathodes，the composition of cathodes materials and the loading methods of sulfur. Traditional methods for cathodes preparation generally include mix sulfur, NMP, binder and conductive materials in a controlled manner. These processes take huge manufacturing time and cost and some of them are not suitable for industrialization. On the other hand, the common load methods of sulfur are electro-deposition, chemical deposition, physical vapour deposition, physical dispersion and so on[16, 21, 22]

. There are also some problems with these methods. For example, the ordinary

sulfur cathode usually requires complex preparation processes. This usually contains that the active material is mixed with conductive additives and binder in solvent, the mixture is smeared on current collector and the electrodes is dried in a temperature-controlled vacuum. And so much chemical reagents unavoidably caused a certain degree of pollution to the environment[23]. Thus, it is worthwhile to develop a


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simple physical approach to a binder-free cathode with high loading amount of S. This paper solve the technological challenges on sulfur cathode, we utilize ternary hybrid materials（Ni, S and C）structures to resolve the disadvantages of sulfur, the double confined S inside compressed nickel foam and pencil-plating graphite protecting layers were prepared by an entire physical procedure (as shown in Figure 1, see more details in experimental section). The ternary hybrid materials where one component Ni foam is used as a metal framework for electron transfer network and the porosity of the nickel foam surface acts as a host of sulfur[24]. The second component sulfur is used as the active material that reaction with lithium ions[17] and the third component carbon layer is used as surface protecting layer to suppress the lithium polysulfides diffusing to the anode side[7]. The preparation of procedure adopted a kind of environmental friendly, simple physical method of tableting which the nickel foam is dripped into the sulfur solution to absorb sulfur and followed by tableting the nickel foam under high pressure to constrain the sulfur on the narrowed 3D network of nickel foam. As a result of the ternary hybrid architecture, when test as cathode for the Li-S battery, our material exhibits a perfect performance in respect to specific capacity, rate capability and cycle stability. It is believed that this strategy may provide a new way for the industrialization of the sulfur cathode piece production. Experimental Section Materials and Apparatus Sublimed sulfur, Carbon disulfide, Nickel foam (thickness, 0.14 mm; area density,



0.028 g/cm2) Models 769yp - 15 - a small manual powder tablet press. X-ray diffraction (XRD) measurements were obtained from a Rigaku Smartlab (9) diffractometer with Cu Kα radiation (Cu Kα X-rays of 0.154nm) and operated at 45kV and 200mA. The scattering range of 2θ was from 5° to 60°, and the scanning rate of 10°/min with a step of 0.02° for the measurements of each sample. X-ray photoelectron spectroscopy (XPS) measurements were determined by a Thermo Fisher Scientific ESCALAB 250Xi with monochromatized Al Kα (1486.6eV) X-ray source under a pressure of 3×10-7 mbar in the analysis chamber during the measurement. All spectra were calibrated with the binding energy of the C1s peak at 284.8eV. Scanning electronic microscopy (SEM) images and EDS mapping were performed using a Hitachi SU8020 electron microscopy operating at 5kV and 10kV. Preparation of NFFS-C The nickel foam/sulfur composite was prepared by an entire physical procedure (Figure 1). In a typical experiment, 1.0 g of sulfur was added to the 10 ml of carbon sulfide solution. The nickel foam was dropped into the sulfur solution, after 1h, all the skeleton of nickel foam was deposited by sulfur through physical adsorption. The as-obtained S loaded nickel foam was named as NFFS for simplicity. Then, after removing the carbon sulfide by vacuum heating, the NFFS was pressed flat under 10MPa by a tablet machine. After the pressure, the S was confined to the interpenetrating network of compressed nickel foam. Finally, the surface of NFFS was coated by a carbon layer through a graffiti process by soft charcoal pencil in which the graphite layers of the pencil fall off and thick covered on the surface of NFFS, the


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as-obtained carbon coated NFFS named as NFFS-C. Cathodes with different sulfur contents were easily prepared by controlling the concentration of sulfur in carbon disulfide. Electrochemical Measurements NFFS-C was used to act as the integrated cathode directly. Binders such as polyvinylidene, N-methyl-2-pyrrolidone (NMP) and Super P carbon were not needed. Coin cells (2032 type) were assembled using lithium foil as the anode and Celgard 3501 sheets as the separator

[25, 26]

. The electrolyte was 1 M lithium bis

(trifluoromethanesulfonyl)imide (LiTFSI) in a mixed solvent of 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) with a volumetric ratio of 1:1 with 1wt % of LiNO3[27]. The electrolyte amount was 35μL. The electrode area was 1.5 cm2 (diameter of 14mm). Electrochemical studies were carried out using MTI BST8-MA and Arbin BT2143 battery analyzers. Cells were operated in the voltage window of 1.8−2.8 V. Coin2032 cells were assembled in a glove box to test the electrochemical properties of the as-prepared cathode.



Results and discussions

Figure 1. A schematic diagram of the procedure for preparing the double confined S electrode, the nickel foam (NF) firstly soaked in S solution, after remove the CS2 solvent by heating, the S was loaded on the framework of NF, then the NF was compressed by tableting, and the surface of NF was coated a carbon layer by pencil-plating, finally the double confined S inside compressed nickel foam and pencil-plating graphite were obtained.

In this work, we report high reactive sulfur pressed in nickel foam as high-powered cathode for lithium sulfur batteries. The preparation methods of the cathode adopt a traditional physical way by tableting machine. Firstly, the nickel foam was dripped into the carbon sulfide solution of sulfur, after the volatilization of carbon sulfide solvent, the sulfur deposited in the framework of nickel foam (we called the sample as NFFS for simplicity). Furthermore, the surface of the pressed nickel foam was coated by a carbon layer by plating graphite flakes by a pencil, obtaining an integrated S cathode (we called the sample as NFFS-C for simplicity),


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without using any additives and binders. All the processes are physical approaches, and nickel foam, sulfur and carbon layer were closely connected under the effect of pressure.

Figure 2.(a) Sublimed sulfur cathode on Ni foam (NFFS) (b) NFFS-C. (c) SEM images of the mesoporous in foam nickel skeleton. (d) SEM and EDS mapping of select area. (e) Element Ni mapping. (f) Element S mapping . (g) Element C mapping.

From our SEM observation (Figure 2c), nickel foam not only have big pore composed by metal skeleton but also have mesoporous and macroporous distribution on the nickel skeleton.The BET surface area of nickel foam is 1.60 m2/g. These pores increase the specific surface area of the nickel foam and facilitate the immobilization of the sulfur [24, 28]. Figure 2a and 2b show the typical SEM images of the NFFS and NFFS-C. The pores of nickel foam were full of sulfur and nickel and sulfur were tightly linked together after tableting. There are a ultrathin carbon layer on the NFFS-C and it's like fabric wrapped in NFFS tightly. The carbon layer could prevent polysulfide into electrolyte and increase the electrical conductivity of the material. The 3D metal skeletons of nickel foam and surface carbon layers stacked up by



graphite can inhibit the expansion of sulfur effectively. Figure 2d shows the cross section of the NFFS-C and the carbon layer could be seen clearly. Figure 2e, 2f and 2g are the image of EDS mapping nickel, sulfur and carbon respectively from that can be seen how the distribution of sulfur and carbon in the NFFS-C sample, further confirmed that that most of the sulfur distribution into the interior of the nickel foam pores and the surface was covered by carbon.

Figure 3.(a) Raman spectra of NFFS-C, NFFS and Ni. (b) XRD patterns of the Ni, NFFS and NFFS-C.

There was typical sulfur signal in NFFS (Figure 3a), but in NFFS-C，there was no sulfur signals and only carbon signals. The NFFS were fully covered by the carbon layer. Figure 3b shows the X-ray diffraction patterns of nickel foam, NFFS and NFFS-C. Compared with the three curves, the new characteristic peaks (at 2 theta 10°, 20°, 30°) of sublimed sulfur were detected on the NFFS sample, demonstrated that the successful loading sulfur on nickel foam. The sharp diffraction peak of sulfur indicated that sulfur were crystalline state

[29]

. Both the crystalline sulfur and carbon


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characteristic XRD were observed in Figure 3b which proved that our simply pencil plating method can introduce a stable carbon layer on the surface of NFFS.

Figure 4. Electrochemical performance of Li−S batteries using the NFFS-C as the cathode.(a) Rate performance. (b) Discharge and charge profiles at 0.1 to 2C. (c) Cycling performance of the NFFS-C electrode at 1 C with a sulfur loading of 0.42, 0.82, 1.15 and 3.32 mg/cm2, respectively. (d) CV profiles recorded at 0.1 mV/s. Specific capacity values were calculated on the basis of the mass of sulfur.

Capacity retention after long cycles over a range of rates is significant for the practical application of Li-S batteries. To evaluate the efficiency of the NFFS-C composite electrode. The NFFS-C ternary material was made into coin-cell type batteries and cycled between 1.8 V and 2.8 V versus Li/Li+ at different current



densities[30]. As shown in Figure 4a, the battery displayed capacities of 1076 (1st cycle, 0.1C), 880 (11th cycle, 0.2C), 680 (21st cycle, 0.5C), 550 (31st cycle, 1C), and 450 (41st cycle, 2C) mAh/g at the sulfur loading of 1.15 mg/cm2 . More importantly, the capacity returns to 1014 mAh/g when the current density turns back to 0.1C (51st cycle), demonstrating good rate performances of the NFFS-C. In the contrast, the rate performance of NFFS was much worse than that of NFFS-C. The carbon layer of NFFS-C was very important for stopping polysulphide dissolving into electrolyte, which not only can effectively alleviate the volume expansion of sulfur but also can adsorb the polysulphide avoid them further transfer. These should be the main reasons for the good rate performance. Figure 4b shows the discharge and charging curves of NFFS-C cathode with a rate of 0.1 to 2 C. The main discharge plateaus and long charge plateau were detected which were typical lithium sulfur battery profiles. Long term cycling performance of the NFFS-C electrode was shown in Figure 4c, indicating the stability of the electrode also depended on the loading amount of sulfur. When the S loading was 0.42 mg/cm2 (Figure 4c ), the electrode showed a high first discharge capacity (1412 mAh/g at 1C) and good circulation performance[31] (Table 1). However, with increasing the S loading, the first cycle capacity and cycling performance declined. We supposed that the interior space of nickel foam was limited and it could hold the quantity of sulfur also was limited. The adsorption of mesoporous and macroporous could not absorb excess sulfur and the carbon layer could not encapsulate overmuch sulfur closely either which led to the bad cycling behavior of the electrode at the cases of


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high loading amount of sulfur (1.15 mg/cm2 and 3.32 mg/cm2).

Table 1. After 150 Cycles, the relationship among the sulfur loading, discharge capacity and capacity retention.

Sulfur loading

First discharge capacity

Capacity retention

(mg/cm2)

(mAh/g)

(%)

0.42

1412

71.8%

0.82

1215

82.3%

1.15

1036

93.4%

3.32

856

92.1%

Cyclic voltammograms (CV) of the NFFS-C electrode at a scan rate of 0.1 mV/s are shown in Figure 4d. During the cathodic scan, peaks at 2.25V was attributed to the reduction of Li2S8 to soluble polysulphide intermediates which merged with two overlapping anodic peaks at 2.55 V and 2.6 V related to the oxidation from short-chain to long-chain polysulfides[18]. In the initial cycle, a peak of 2.25 V appears, which was attributed to the formation of insoluble Li2S2 and Li2S from small sulfur molecule S42- . In addition, a small cathodic peak at 2.3 V appeared in the first cycle, but in subsequent cycles it disappeared completely which was mainly ascribed to the dissolution of a trace of sulfur on the outer surface of the electrode[32]. In the subsequent cycles, the cathodic peak shifts from 2.2 V to 2.25 V and the CV curves



almost overlap, suggesting a high reversibility of the NFFS-C.

Figure 5. SEM images and maps of element in the NFFS-C sample after long-term cycling (150 cycles). (a) SEM image of the selected region. (b) SEM image of the skeleton of nickel foam. (c) The appendages growing on foam nickel skeletons. EDS maps of (d) Ni, (e) S, (f) C in the selected regions of the cycled NFFS-C.

After more than 150 cycles in 1 C, the 3D network NFFS-C still maintained (Figure 5a), which suggested that the high stability of the electrode. However, when we observed the microstructure of the electrode at high magnification, plenty of nanoparticles were observed on the skeleton of nickel foam (Figure 5b). As the surface of nickel foam

reacted constantly, more pores were exposed in the skeleton.

Figure 5c shows the sulfur and carbon layer in the middle of the skeleton of nickel foam. It could see clearly that carbon layer is still tightly covered on the surface of the nickel foam. EDS mapping of Ni, S and C of the NFFS-C after 100 cycles are shown


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in Figure 5d, 5e and 5f, respectively. It can be seen sulfur and carbon evenly distributed on the sample. Further confirmed the high stability of our ternary hybrid electrode materials [33].

Figure 6. Wide-scan survey XPS spectra of NFFS-C. Elemental XPS spectra of (a) C 1s, (b)O 1s, (c) Ni 2p and (d) S 2p.

This data was used to identify the bonding characteristics and to obtain an accurate surface composition of the as synthesized sulfur and composites. X-ray photoelectron spectroscopy (XPS) was further used to identify the bonding characteristics and to obtain an accurate surface composition of the as-synthesized



sulfur and composites. Figure 6 shows the XPS spectrum of the NFFS-C composite electrode. The obvious signals of C and S in the as-synthesized NFFS-C composite further reveal the full growth of sulfur in the nickel foam. In the C 1s spectrum, the main peak corresponds to sp2-hydridized carbon (at 284.6eV) corresponding to the carbon of NFFS–C[32, 34]. Figure 2c shows the S 2p spectrum and the results of the deconvolution, revealing spectra corresponding to various valence states of sulfur; five sulfur environments were identified. NFFS-C and S 2p, the spectra show two partially overlapping doublets attributed to S22− pairs (on the high-energy side) and S2− (on the low-energy side) in 1:2 proportions as observed in a previous report[35]. The single peak located at 164eV was assigned to the S–S bond from elemental sulfur; the other two peaks between 169 and 170 eV were due to the presence of SO42− or SO32− which were likely to produce through the oxidation of sulfur during the hydrothermal reaction[36]. The binding energy of the main peaks of the Ni 2p spectrum were consistent with Ni2SO4 and Ni2SO3, which further confirmed the formation of a pure Ni2SO4 phase[34]. Typical peaks of Ni 2p are strong multiple peaks between 855 and 860 eV. Since the surface properties of the carbon materials also played an important role in the electrochemical reactions, the NFFS-C hybrid was further investigated by X-ray photoelectron spectroscopy (XPS) and the results reported that sulfur was still coated with carbon layer. The carbon layer made effect on reducing the volume of sulfur and bounding the polysulfide, improving the cycling stability of the lithium sulfur battery[7, 37].


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Figure 7. (a) EIS spectra of fresh cells with NFFS-C cathode, CMK-3/S cathode, and bulk S cathode. (b) EIS spectra of NFFS-C cathode after 2nd, 5th, 20th, 50th, and 100th discharge.

Electrochemical impedance spectroscopy (EIS) is also a useful method for analyzing cyclic changes. The resistance comparison of fresh cells with bulk S, CMK-3/S and NFFS-C cathode is shown in Figure 7a. The charge-transfer resistances of bulk S, CMK-3/S and NFFS-C cathode are 424.2, 87.6, and 25.8 Ω, respectively. The smaller resistance contributes to fast electron transfer in NFFS-C cathode and better rate performance. The resistance along with cycling was also investigated to explain the cycling stability. As shown in Figure 7b, the NFFS-C electrode, after activation of the first cycle, the resistance became quite stable and a charge-transfer resistance of less than 15Ω was observed at 100 cycles . This small and stable resistance also should be benefit to the better cycling performance. Conclusions Double confined sulfur inside compressed nickel foam and pencil-plating



graphite was prepared by a totally physical process, including absorption of S by nickel foam, compressed at high pressure and coating a cabon layer on the outer surface by pencil-plating graphite flakes. As a result of the ternary hybrid architecture, our material exhibits balanced high performance with respect to specific capacity, rate capability, and cycling stability. For example, The capacity still maintained 895 mAh/g at 1 C after 100 cycles. This integrated sulfur cathode was prepared by pure physical methods without using any additives and binders, shortened the process of the traditional cathode preparation which should be more suitable for industrial production of high performances S cathode materials in lithium sulfur battery technology. Our methods of preparing electrodes supply a thinking for the industrialization. Electrochemical reactions among Ni, S and C in lithium sulfur battery were further demonstrated in the cathode of sulfur and carbon on nickel foam from in SEM and XPS tests. This cathode of sulfur and carbon on nickel foam was prepared by pure physical methods ,shortened the process of the traditional cathode preparation. Thus, this physical methods should be more suitable for industrial production.


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AUTHOR INFORMATION Corresponding Authors *Email: [email protected]. *Email: [email protected] *Email: [email protected].

Notes The authors declare no competing financial interest.

Acknowledgments This work was supported by National Natural Science Foundation of China (No. 91534109, 91434203, and 51306194), National Key Projects for fundamental Research and Development of China (2016YFB0100104), the “Strategic Priority Research Program ” of the Chinese Academy of Sciences (Grant No. XDA09010103), Beijing Municipal Science and Technology Project (D171100005617001) and Henan province science and technology cooperation project (172106000061).



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Notes and References 1.

Table 12. Natural gas deliveries to residential consumers, by state. 2007-2009. Natural Gas Monthly, 2009.

2.

Cheng, F.; Shen, J.; Peng, B.; Pan, Y.; Tao, Z. l. Rapid room-temperature synthesis of nanocrystalline spinels as oxygen reduction and evolution electrocatalysts. Nat. Chem. 2011, 3, 79-84.

3.

Xin, S.; Gu, L.; Zhao, N. H.; Yin, Y. X.; Zhou, L. J. Smaller sulfur molecules promise better lithium–sulfur batteries.

J. Am. Chem. Soc.

2012,

134,18510-18513. 4.

Cheng, F.; Liang, J.; Tao, Z.; Chen, J. Functional materials for rechargeable batteries. Adv. Mater. 2011, 23, 1695-1715.

5.

Choi, N. S.; Chen, Z.; Freunberger, S. A.; Ji, X.; Sun, Y. K. Challenges facing lithium batteries and electrical double-layer capacitors. Angew. Chem. Int .Ed. Engl. 2012, 51, 9994-10024.

6.

Wei, S.; Xu, S.; Akanksha, A.; Snehashis, C.; Lu, Y. A stable room-temperature sodium-sulfur battery. Nat. Commun. 2016, 7, 11722-11734.

7.

Wang, H.; Yang, Y.; Liang, Y.; Robinson, J. T,; Li, Y. Graphene-wrapped sulfur particles as a rechargeable lithium–sulfur battery cathode material with high capacity and cycling stability. Nano. Lett. 2011, 11, 2644-2647.

8.

Zheng, G.; Yang, Y.; Cha, J. J.; Hong, S. S.; Cui, Y. Hollow carbon nanofiber-encapsulated sulfur cathodes for high specific capacity rechargeable lithium batteries. Nano. Lett. 2011, 11, 4462-4468.


Page 21 of 33 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


9.

Yao, H.; Yan, K.; Li, W.; Zheng, G.; Kong, D. Improved lithium–sulfur batteries with a conductive coating on the separator to prevent the accumulation of inactive S-related species at the cathode–separator interface. Energ. Environ. Sci. 2014, 7, 3381-3390.

10.

Kim, J. H.; Fu, J. K.; Choi, J.; Kil, K.; Kim, J. Encapsulation of S/SWNT with PANI web for enhanced rate and cycle performance in lithium sulfur batteries. Sci. Rep. 2015, 5, 8946-8955.

11.

Hwa, Y.; Zhao, J.; Cairns, E. J. Lithium sulfide (Li2S)/graphene oxide nanospheres with conformal carbon coating as a high-rate, long-life cathode for Li/S cells. Nano. Lett. 2015, 15, 3479-3492.

12.

Ji, X.; Lee, K. T.; Nazar, L. F. A highly ordered nanostructured carbon-sulphur cathode for lithium-sulphur batteries. Nat. Mater. 2009, 8, 500-507.

13.

Pang, Q.; Kundu, D.; Cuisinier, M.; Nazar, L. F. Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries. Nat. Commun. 2014, 5, 4759-4768.

14.

Zheng, J.; Tian, J.; Wu, D.; Gu, M.; Xu, W. Lewis acid-base interactions between polysulfides and metal organic framework in lithium sulfur batteries. Nano. Lett. 2014, 14, 2345-2353.

15.

Ji, X.; Evers, S.; Black, R.; Nazar, L. F. Stabilizing lithium-sulphur cathodes using polysulphide reservoirs. Nat. Commun. 2011, 2, 325-332.



16.

Wang, L.; Dong, Z.; Wang, D.; Zhang, F.; Jin, J. Covalent bond glued sulfur nanosheet-based cathode integration for long-cycle-life Li-S batteries. Nano. Lett. 2013, 13, 6244-6256.

17.

Zhi, W. S.; Li, W.; Cha, J. J.; Zheng, G.; Yang, Y. Sulphur-TiO2 yolk-shell nanoarchitecture with internal void space for long-cycle lithium-sulphur batteries. Nat. Commun. 2013, 4, 1331-1342.

18.

Pang, Q.; Liang, X.; Kwok, C. Y.; Nazar., L. F. Advances in lithium–sulfur batteries based on multifunctional cathodes and electrolytes. Nat. Energy, 2016, 1, 16132-16143.

19.

Su, Y. S.; Fu, Y.; Cochell, T.; Manthiram, A. A strategic approach to recharging lithium-sulphur batteries for long cycle life. Nat. Commun. 2013. 4, 2985-2998.

20.

Zhao, Q.; Hu, X.; Zhang, K.; Zhang,

N.; Hu, Y. Sulfur nanodots

electrodeposited on ni foam as high-performance cathode for Li-S batteries. Nano. Lett. 2015, 15, 721-742. 21.

Wang, H.; Zhang, W.; Liu, H.; Guo, Z. A strategy for configuration of an integrated flexible sulfur cathode for high-performance lithium-sulfur batteries. Angew. Chem. Int. Ed. Engl. 2016, 55, 3992-4003.

22.

Xu, F.; Tang, Z.; Huang, S.; Chen, L.; Liang, Y. Facile synthesis of ultrahigh-surface-area hollow carbon nanospheres for enhanced adsorption and energy storage. Nat. Commun. 2015, 6, 7221-7232.


Page 22 of 33

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23.

Nan, M.; Min, F.; Wan, F.; Hong, F.; Yue, G. Chemical routes toward long-lasting lithium/sulfur cells. Nano. Res. 2016, 9, 94-116.

24.

Bao,

W.;

Su,

D.;

Zhang,

W.;

Guo,

X.;

Wang,

G.

3D

metal

carbide@mesoporous carbon hybrid architecture as a new polysulfide reservoir for lithium-sulfur batteries. Adv. Funct. Mater. 2016, 26, 8746-8756. 25.

Zhang, X.; Cheng, F.; Yang, J.; Chen, J. LiNi(0.5)Mn(1.5)O4 porous nanorods as high-rate and long-life cathodes for Li-ion batteries. Nano. Lett. 2013, 13, 2822-2832.

26.

Li, G.; Sun, J.; Hou, W.; Jiang, S.; Huang, Y. Three-dimensional porous carbon composites containing high sulfur nanoparticle content for high-performance lithium-sulfur batteries. Nat. Commun. 2016. 7, 10601-10614.

27.

Yang, Y.; Zheng, G.; Misra, S.; Nelson, J.; Toney, M. F.; High-capacity micrometer-sized Li2S particles as cathode materials for advanced rechargeable lithium-ion batteries. J. Am. Chem. Soc. 2012. 134, 15387-15398.

28.

Liu, J.; Yang, T.; Wang, D. W.; Lu, G. Q.; Zhao, D. A facile soft-template synthesis of mesoporous polymeric and carbonaceous nanospheres. Nat. Commun. 2013, 4, 1124-1136.

29.

Zhou, J.; Li, R.; Fan, X.; Chen, Y.; Han, R. Rational design of a metal–organic framework host for sulfur storage in fast, long-cycle Li–S batteries. Energ. Environ. Sci. 2014, 7, 2715-2726.

30.

Zhou, G.; Paek, E.; Hwang, G. S. A Manthiram, Long-life Li/polysulphide batteries with high sulphur loading enabled by lightweight three-dimensional



nitrogen/sulphur-codoped graphene sponge.

Nat.

Page 24 of 33

Commun.

2015,

6,

7760-7781. 31.

Zhu, Z.; Wang, S.; Du, J.; Jin, Q.; Zhang, T. Ultrasmall Sn nanoparticles embedded in nitrogen-doped porous carbon as high-performance anode for lithium-ion batteries. Nano. Lett. 2014, 14, 153-166.

32.

Wang, Z.; Dong, Y.; Li, H.; Zhao, Z.; Wu, H. B. Enhancing lithium-sulphur battery performance by strongly binding the discharge products on amino-functionalized reduced graphene oxide. Nat. Commun. 2014, 5, 5002-5013.

33.

Jiang, J.; Zhu, J.; Ai, W.; Wang, X.; Wang, Y. Encapsulation of sulfur with thin-layered nickel-based hydroxides for long-cyclic lithium-sulfur cells. Nat. Commun. 2015, 6, 8622-8636.

34.

Zhang, J.; Yang C.; Yin, Y.; Wan, L.; Guo, Y. Sulfur encapsulated in graphitic carbon nanocages for high-rate and long-cycle lithium-sulfur batteries. Adv. Mater. 2016, 28, 9539-9544.

35.

Liang, X.; Hart, C.; Pang, Q. Garsuch, A.; Weiss, T. A highly efficient polysulfide mediator for lithium-sulfur batteries. Nat. Commun. 2015, 6, 5682-5689.

36.

Lei, T.; Chen, W.; Huang, J.; Yan, C.; Sun, H. Multi-functional layered WS2 nanosheets for enhancing the performance of lithium-sulfur batteries. Adv. Energy Mater, 2017, 7, 1843-1856.


Page 25 of 33 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


37.

Zhang, J. F.; Hu, Y. C.; Liu, D. L.; Yu, Y.; Zhang, B. Enhancing oxygen evolution reaction at high current densities on amorphous-like Ni-Fe-S ultrathin nanosheets via oxygen incorporation and electrochemical tuning. Adv. Sci. 2017, 4, 343-356.



Table of contents:


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Figure 1 22x12mm (600 x 600 DPI)





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Figure 7 178x69mm (300 x 300 DPI)


Double-Confined Sulfur Inside Compressed Nickel Foam and Pencil

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