Letter Cite This: J. Phys. Chem. Lett. 2017, 8, 5331-5337
pubs.acs.org/JPCL
Electrochemical Properties of Sulfurized-Polyacrylonitrile Cathode for Lithium−Sulfur Batteries: Effect of Polyacrylic Acid Binder and Fluoroethylene Carbonate Additive Hee Min Kim,† Jang-Yeon Hwang,† Doron Aurbach,‡ and Yang-Kook Sun*,† †
Department of Energy Engineering, Hanyang University, Seoul 04763, South Korea Department of Chemistry and BINA (BIU Institute of Nano-technology and Advanced Materials), Bar-Ilan University, Ramat-Gan 5290002, Israel
‡
S Supporting Information *
ABSTRACT: Sulfurized carbonized polyacrylonitrile (S-CPAN) is a promising cathode material for Li−S batteries owing to the absence of polysulfide dissolution phenomena in the electrolyte solutions and thus the lack of a detrimental shuttle mechanism. However, challenges remain in achieving high performance at practical loading because of large volume expansion of S-CPAN electrodes and lithium anode degradation at high current densities. To mitigate this problem, we propose a novel cell design including poly(acrylic acid) (PAA) binder for improved integrity of the composite electrodes and fluoroethylene carbonate (FEC) as additive in the electrolyte solutions for stabilizing the lithium metal surface. As a result, these cells delivered high initial discharge capacity of 1500 mAh g−1 and a superior cycling stability ∼98.5% capacity retention after 100 cycles, 0.5 C rate, and high sulfur loading of 3.0 mg cm−2. Scaled-up 260 mAh pouch cells are working very well, highlighting the practical importance of this work.
L
nonreactive backbone. Such structures can allow all sulfur atoms in the composite materials to become fully electrochemically active, without any problem of sulfide species dissolution. Moreover, such structures can serve as universal cathodes that can react with several ions: Na+, K+, and even bivalent cations like Mg2+ and Ca2+. We prepared novel sulfurized polyacrylonitrile cathodes by melting sulfur into carbonized polyacrylonitrile (CPAN) polymer. As the charge− discharge mechanism of sulfurized CPAN (S-CPAN) cathodes is different from that of most sulfur cathode Li−S batteries, it has the benefit of bypassing the Li-sulfides dissolution phenomenon and the shuttle problem, thereby preventing active material loss. In addition, the lack of soluble Li-sulfide formation allows the use of carbonate-based electrolyte solutions (provided that the right selection of materials has been made), instead of the ether-based electrolyte solutions used in conventional Li−S batteries. Conventional Li-sulfides formed by sulfur reduction in Li−S cells are very nucleophilic and hence react readily with electrophilic alkyl carbonates.16 In addition, alkyl carbonate solvents are highly reactive with lithium metal anodes.17 Therefore, in conventional Li−S batteries the much less reactive ether-based solutions, with lower ionic conductivity have to be used, despite their safetyrelated disadvantages: high volatility and high flammability. The limited ionic conductivity of some ether-based solutions can
ithium-ion batteries have provided the foundation for the development and explosive growth of IT devices and other portable electronic devices.1,2 With recent developments in Liion batteries, they have been applied to larger devices such as electric cars, airplanes, and drones. However, because of limitations in availability of active materials, high cost of raw materials, environmental concerns, and demand for higher energy densities as Li-ion batteries approach their theoretical limit, the market has been looking for alternative energy storage systems (ESSs).3,4 In this regard, Li−S batteries are among the more auspicious candidates as next-generation ESSs, owing to the abundance and inexpensive cost of raw sulfur, environmental benignity, theoretical capacity of 1675 mAh g−1 for sulfur cathodes, and theoretical energy density of 2500 Wh kg−1 for these ESSs.5,6 Yet, in spite of their benefits, Li−S batteries have not been successfully commercialized to date because they suffer from several problems: (1) Li-sulfide dissolution and their shuttle reactions that avoid full oxidation of the Li-sulfides to sulfur in the cathodes, (2) volatility of the conventional ether-based electrolyte solutions (necessary to operate Li−S batteries properly), and (3) only a partial utilization of sulfur at the cathodes due to the low sulfur conductivity of 5 × 10−30 S cm−1.7−10 To circumvent these issues, alternative Li−S batteries were developed with a revolutionary cathode concept.11−15 Special reactive electrolyte solutions were used with surface reactions on the electrodes, which stabilize both negative and positive sides. Ideal sulfur cathodes may include active sulfur moieties, which are chemically bound to an electronically conductive, © 2017 American Chemical Society
Received: September 5, 2017 Accepted: October 17, 2017 Published: October 17, 2017 5331
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
Letter
The Journal of Physical Chemistry Letters
Figure S1 shows SEM images of the synthesized PAN and SCPAN. Both have flake-like morphologies; the size of the PAN particles was ∼50 nm, and S-CPAN had a larger particle size of ∼100 nm due to agglomeration of the PAN particles during thermal treatment with sulfur. Nevertheless, the heat-treated material maintains the form of nanosheets and has a large surface area. The bonding structure of S-CPAN was analyzed using Fourier transform infrared (FT-IR) spectroscopy (Figure S2). As seen in Figure S2a, the FT-IR spectra of S-CPAN show significantly different peaks compared to that of PAN; the FTIR peaks of S-CPAN are outlined in Table S1. This disparity is due to the structural change of PAN during pyrolysis; the original linear PAN structure transforms into a six-membered ring chain, as shown in the bottom right corner of Figure S2a. Note that the carbon backbone peaks of the resulting pyrolyzed PAN are in accordance with the literature.24,38 Three additional peaks (circled in blue) indicate the successful sulfurization of PAN: the 943 cm−1 peak is due to ring breath of the side-chain that contains S−S bonds; the 671 cm−1 stretch is due to C−S bonding, and the 513 cm−1 stretch peak arises from S−S bonding.24 To further affirm the successful synthesis of SCPAN, thermogravimetric analysis (TGA) was performed. As seen in Figure S2b, sulfur begins to vaporize at ∼200−300 °C, while the TGA of S-CPAN shows no signs of vaporization and exhibits a behavior similar to that of CPAN. These results indicate that there is no pure sulfur on the surface of S-CPAN, indicating its successful synthesis. Note that this is different from the commonly tested sulfur impregnation into carbon matrices, because in the cathode material explored herein sulfur is chemically bonded directly to the carbonaceous backbone. Elemental analysis confirmed the presence of sulfur in the SCPAN composite material as pointed out in Table 1, which
reduce the rate capability of Li−S batteries. There is only one case where alkyl carbonate-based solutions were used successfully in Li−S batteries, which was already demonstrated and discussed in the literature:18,19 when the sulfur is fully encapsulated in suitable carbon matrices and is isolated from the solution phase by solid electrolyte interface (SEI) type surface films, which allow Li ion transport, yet avoid direct contact of Li-sulfide moieties with solvent molecules (the quasisolid mechanism of reversible sulfur lithiation).20 The successful operation of S-CPAN cathodes was indeed achieved in this work. Moreover, PAN possesses nitrile groups, which dope the polymer-originated carbons with nitrogen upon carbonization, which enhances the conductivity and sulfur utilization. Despite the aforementioned possible advantages of S-CPAN cathodes, high sulfur loading (when using S-CPAN cathodes) still faces challenges similar to those of a traditional Li−S battery. The periodic volume expansion due to sulfur reduction to S−Li moieties shatters any composite sulfur cathode structure during cycling, including that of S-CPAN cathodes. Also, lithium metal degradation, a chronic problem in Li−S batteries, occurs at high current densities especially at practical loading, where Li metalequivalent to several mAh cm−2is dissolved or deposited at each cycle. Efforts have been made by several research groups to resolve these problems, including the use of gel polymer electrolytes, working with nanoscale dimensions, and the formation of PAN−carbon and PAN−metal oxide composites. However, many of these endeavors were performed using electrodes with low sulfur loading levels, and unstable performances were revealed at high sulfur loading on aluminum foil current collectors (CC). To take advantage of the unique charge−discharge mechanisms of S-CPAN electrodes at high sulfur loadings, we introduce a novel cell design through the application of poly(acrylic acid) (PAA) binder to S-CPAN electrodes using alkyl carbonate-based electrolyte solutions with fluoroethylene carbonate (FEC) as an additive. PAA-based binders were found to be superior over PVdF in a previous work, in terms of excellent adhesion and cohesion properties of composite electrodes.21 FEC is considered a “magic” additive or cosolvent in Li salt electrolyte solutions, working with Li metal or Li−Si anodes and high-voltage Li insertion cathodes or S−C composite cathodes,22,23 as its surface reactions lead to polymerization and formation of effectively passivating surface films.22,23 PAN-based sulfur electrodes were already reported in the literature.24−35 Here, we tested S-CPAN cathodes with high (fully practical) loading. We found that Li−S cells comprising S-CPAN cathodes with PAA binder resolve the inherent problems of cathode structure fragmentation through hydrogen bonding of S-CPAN-PAA and S-CPAN-PAA-Al2O3, which strengthens the cathode structure.36,37 The presence of FEC also adds to the stabilization of the cathodes as we explain herein. However, a major advantage of using FEC-containing solutions is the stabilization of the lithium metal anodes by formation of passivating surface films. The combination of these three componentsS-CPAN, PAA, and FECresulted in outstanding electrochemical performance of practically loaded sulfur cathodes with stable cycle life. We demonstrated pouch cells, which contained 100 mAh S-CPAN cathodes with a specific capacity around 3 mAh cm−2, which exhibited very stable capacity during more than 100 cycles. Moreover, the scale-up pouch cells with four electrodes connected in parallel has cell capacity of 260 mAh.
Table 1. Elemental Analysis Data: Atomic Content (C, H, N, S) of PAN and S-CPAN (wt %)
C
H
N
S
PAN S-CPAN
67.8 39.8
5.8 0.5
26.4 14.7
0 45.0
shows the C, H, N, and S content (wt %). During the heat treatment process, the nitrile groups dope the pyrolyzed PAN with nitrogen, and sulfur also bonds to the corresponding PAN structure. The average sulfur content in the S-CPAN was around 45%, and the N-doping level was ∼18%. Figure 1 shows electrochemical cycling data and SEM images of S-CPAN electrodes (3 mg cm−2 sulfur loading) with PVdF and PAA binder. The S-CPAN electrodes containing PVdF binder showed an initial capacity of 1356 mAh g−1 at 0.5 C and a capacity retention of 33% after 100 cycles, while S-CPAN electrodes containing PAA binder delivered a slightly improved electrochemical performance of 1500 mAh g−1 at 0.5 C with 49% capacity retention after 100 cycles. The superiority of SCPAN cathodes with PAA binder compared to the same electrodes with PVdF presented in Figure 1a was confirmed further in a series of parallel experiments. The capability of cycling the cells one hundred times in the alkyl carbonate solutions is very important; it shows that, unlike free Li-sulfide species, the sulfur anions, which are formed by reduction of the cathodes upon discharge and are bound to the carbonaceous backbone of CPAN, do not react with the alkyl carbonate. Hence, we can operate the S-CPAN cathodes in optimized alkyl 5332
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
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The Journal of Physical Chemistry Letters
Figure 1. (a) Cycle retention graph and (b) charge−discharge curve graph of S-CPAN cells with PVdF and PAA binders. SEM images of (c) surface and cross section of S-CPAN with PVdF binder electrode, (d) lithium metal surface of S-CPAN cell with PVdF binder, (e) surface and cross section of S-CPAN with PAA binder electrode, and (f) lithium metal surface of S-CPAN with PAA binder after 100 cycles. We confirmed by enough measurements that the SEM images in this figure represent very well the true electrode morphology.
carbonate solutions, thus benefiting from operating Li−S cells which contain much less dangerous solutions compared to conventional Li−S systems. In order to ascertain the cause of the decline in cycling performance, cycled S-CPAN cathodes and lithium metal anodes were measured after cycling (post mortem analysis), and the surface and cross section of the electrodes were analyzed by SEM, as shown in Figure 1c−f. As seen in the images, the S-CPAN electrodes with PVdF binder showed extensive cracking on the surface, and the cathode structure detached from the aluminum foil CC, such that parts of the cathodes’ active mass fell off.28,30 On the other hand, S-CPAN electrodes with PAA binder showed no signs of cracking or separation between the composite active mass of the cathode and the aluminum foil CC, such that the overall cathode structure was retained. This structural retention can be attributed to the strong adhesion of PAA to the cathode components via hydrogen bonding between the carboxylate groups of PAA and both the OH groups of the carbonized PAN and the aluminum oxides of the CC. Yushin et al. reported that the hydrogen bonding interaction of PAA shows high elasticity
and suppresses the volume expansion of silicon electrodes during lithiation; in similar fashion, PAA enables accommodating of the S-CPAN volume expansion.36,37,39,40 Despite the cohesiveness of the electrodes containing the PAA binder, the lithium metal anodes in all of the cells show considerable degradation and extensive dendrite growth on the surface, explaining the poor capacity retention of cells with cathodes containing either PVdF or PAA binders. As demonstrated above, the improvement due to using a very good binder cannot ensure a stable cycling performance of these Li/S-CPAN cells, as the lithium metal anodes undergo severe degradation, especially at high current density15,41−43 and at high cathode loading (a few mAh cm−2), which results in high specific discharge and charge capacities. The capability of S-CPAN cathodes to function in alkyl carbonate solutions with no interference of nucleophilic side reactions, as explained above, opens the door to using optimized electrolyte solutions, which can be very suitable for lithium metal anodes as well. It was demonstrated that alkyl carbonate solutions, which contain FEC as an additive or cosolvent, can stabilize lithium metal anodes because of unique surface reactions that form 5333
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
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Figure 2. (a) Cycle retention graph, (b) charge−discharge curve graph, (c) SEM image of the cathode surface and cross section, and (d) SEM image of the lithium metal surface of S-CPAN cell with PAA binder and 5 wt % FEC solution after 100 cycles.
Figure 3. (a) Rate capability data, (b) EIS graph, (c) dQ/dE plot of initial cycle, and (d) dQ/dE plot after 100 cycles of S-CPAN cells with PVdF binder (black), PAA binder (blue), and PAA binder with EC-DEC-FEC/LiPF6 solution (red).
highly effective passivating surface films that behave as a very stable protective SEI on the lithium metal surface.28,29 Despite its auspicious performance with lithium metal, the FEC additive could not previously be used in conjunction with conventional Li−S electrodes because of reactions with the nucleophilic Li-
sulfides formed by discharging conventional sulfur cathodes. Here we can use optimal S-CPAN cathodes that contain PAA (as discussed above) with optimized electrolyte solutions containing 5% FEC. At such concentrations, FEC serves as a reactive solution species, whose surface reactions on the 5334
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
Letter
The Journal of Physical Chemistry Letters
Figure 4. (a) Cell capacity, specific capacity/cycle life graph, and (b) charge/discharge curves of S-CPAN-based pouch-type cells comprising two electrodes, with PAA binder (at the cathode) and EC-DEC-FEC/LiPF6 solution (c) cell capacity, specific capacity/cycle life graph, and (d) charge/ discharge curves of S-CPAN pouch-type cells containing four electrodes with PAA binder at the cathodes and EC-DEC-FEC/LiPF6 electrolyte solution.
electrodes form effectively passivating surface films (relevant to both Li anodes and sulfur cathodes18−23). The manner in which FEC affects the surface chemistry of lithium, Li−Si anodes, and S−C cathodes was explained previously.18−23 Li/S-CPAN cells with EC-DEC-FEC/LiPF6 at a high cathode loading had initially a specific capacity of 1530 mAh g−1 at 0.5 C, indicating a sulfur utilization of about 90% and outstanding capacity retention of 98.5% after 100 cycles (Figure 2a). Cycled SCPAN cathodes and lithium metal electrodes were analyzed with SEM (post-mortem analysis). SEM images of these electrodes (Figure 2c,d) revealed that the cathode structure remained intact with no cracking or peeling off and that the lithium metal surface was much cleaner with no signs of severe degradation typical to used lithium metal anodes measured after cycling in cells without FEC (Figure 2f). Hence, we present herein high-performance Li−S batteries, with S-CPAN cathodes containing PAA binder and stabilized lithium metal anodes in electrolyte solutions that contain FEC. Additional electrochemical tests revealed further improved electrochemical performance of these Li/S-CPAN cells (containing PAA binder and FEC additive), as shown in Figure 3. Li−S cells with different S-CPAN cathodes, PVdF versus PAA binders, and different solutions, EC-DEC/LiPF6 versus EC-DEC-FEC/ LiPF6, were compared in short-term cycling experiments, in which their rate capability was measured. Owing to the short duration of these experiments, the capacity fading was not yet pronounced; therefore, differences in specific capacity due to operation at different rates provide a good indication for the comparative performance. As presented in Figure 3, all the above cells exhibited similar rate capabilities at low C rates. However, at higher rates of 1 and 3 C, cells with S-CPAN/PAA cathodes and solutions that contain FEC showed much better performance (spectacular in the case of Figure 3a). Impedance spectroscopic measurements
of these cells further indicated that the cells with PAA binder and FEC exhibit the lowest impedance. While such EIS measurements have only qualitative significance, they are important as they are coherent with the galvanostatic rate capability measurements. In general, the LiF-rich SEI layer formed by reduction of FEC on lithium, which avoids continuous reaction between the electrolyte solution and lithium metal anode, is uniform and reduces or even avoids lithium dendrite and dead lithium formation. Figure 3c shows plots of dQ/dE, the derivative of the voltage profile measured in galvanostatic measurements, verses E for these cells, initially and after 100 cycles. While initially the plots of these cells, shown in Figure 3c, are very similar (reflecting similar pristine electrodes), the plots measured after 100 cycles, presented in Figure 3d, are different and interesting. The plots for cells without FEC in solution, with PVdF binder, or even with PAA binder, were very different after cycling compared to the initial plots (Figure 3, panel d vs panel c). In contrast, cycled Li/SCPAN cells with PAA and FEC exhibited plots that were very similar to the initial plots, indicating the very high stability of these cells and the advantages of their components, as discussed above. Hence, we describe here new cells with several advantages compared to most Li−S cells described to date in the literature: aluminum foil CC can be used; high cathode loading is possible while retaining the composite active mass (owing to the highly adhesive PAA binder); nonvolatile, relatively nonflammable alkyl carbonate solutions may be employed (in contrast to conventional systems, which use volatile DOL−DME-based solutions); and the Li-metal anodes are stabilized (because of the use of solutions that contain FEC). In order to examine the viability of Li−S cells with S-CPAN/ PAA cathodes and solutions that contain FEC under more realistic conditions, we assembled pouch cells in which 100 5335
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
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mAh two electrodes could be tested. The results of the experiments with these pouch cells are presented in Figure 4. In general, high-sulfur loading cells do not work well in pouchtype configuration because of lithium metal degradation at high current density and evaporation of the volatile ether-based DME/DOL electrolyte, which may create gaps between the electrodes. However, using the combination of S-CPAN/PAA cathodes with FEC-containing solutions, we have successfully cycled such pouch cells, demonstrating very good operation: 100 cycles at high loading and high current density. Compared to the performance shown in coin-type cells (Figure 2), the charge−discharge specific capacities were lower with pouch cells. However, the capacity retention with the latter cells was excellent: a specific capacity of 970 mAh g−1 after 100 cycles at 0.5 C, reflecting a 97.5% capacity retention compared to the first cycle. The configuration of these cells was further scaledup, to 260 mAh pouch cells with four electrodes connected in parallel. These cells also demonstrated impressive stability during cycling. We believe that such cells are very suitable for mass production as well, owing to the easily fabricated cathodes with aluminum foil CC, excellent PAA binder, nonvolatile solutions, and Li metal foil anodes. In summary, S-CPAN was successfully synthesized and was shown to be an excellent active material for composite sulfur cathodes in Li−S batteries. Using such cathode material, in which the sulfur atoms are bound to carbonaceous backbones, has many advantages, including a high specific capacity, stability, and nonreactivity with electrophilic alkyl carbonate solutions. Hence, there are no intrinsic limitations on operating S-CPAN cathodes in nonvolatile, highly conductive alkyl carbonate solutions. Choosing PAA as the binder ensures an excellent cohesion of the active mass, as well as an excellent adhesion to the current collector. Hence, it was possible to fabricate and test high loading/high areal specific cathodes using aluminum foil as CC. Their prolonged cycling demonstrated very impressive mechanical stability, owing to the use of the PAA binder. The compatibility of S-CPAN cathodes with alkyl carbonate solutions enabled unique optimization, by using solutions that contain FEC. This cosolvent is highly reactive with Li metal; however, its surface reactions on lithium form polymeric matrices comprising excellent SEI, in which crystallites of LiF are embedded, allowing very good transport of Li ions through the surface films, while providing excellent passivation for the Li metal anodes. Coin-type cells with these components showed an extraordinary capacity retention of 98.5% after 100 cycles at 0.5 C. This excellent performance could be demonstrated in scaledup 100 mAh pouch cells as well, showing 97.5% capacity retention after 100 cycles. Taking into account the high loading of the cathodes, the high rates that were demonstrated, and the excellent capacity retention after 100 cycles, it appears that the results presented herein are important, opening the door for true practical development of Li−S batteries.
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Letter
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Doron Aurbach: 0000-0001-8047-9020 Yang-Kook Sun: 0000-0002-0117-0170 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by the Global Frontier R&D Program (2013M3A6B1078875) on Center for Hybrid Interface Materials (HIM) funded by the Ministry of Science, Information & Communication Technology (ICT) and the Human Resources Development program (No. 20154010200840) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy.
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REFERENCES
(1) Yoshino, A. The Birth of the Lithium-Ion Battery. Angew. Chem., Int. Ed. 2012, 51 (24), 5798−5800. (2) Amine, K.; Belharouak, I.; Chen, Z.; Tran, T.; Yumoto, H.; Ota, N.; Myung, S.-T.; Sun, Y.-K. Nanostructured Anode Material for HighPower Battery System in Electric Vehicles. Adv. Mater. 2010, 22 (28), 3052−3057. (3) Choi, N.-S.; Chen, Z.; Freunberger, S. A.; Ji, X.; Sun, Y.-K.; Amine, K.; Yushin, G.; Nazar, L. F.; Cho, J.; Bruce, P. G. Challenges Facing Lithium Batteries and Electrical Double-Layer Capacitors. Angew. Chem., Int. Ed. 2012, 51 (40), 9994−10024. (4) Tarascon, J. M.; Armand, M. Issues and Challenges Facing Rechargeable Lithium Batteries. Nature 2001, 414 (6861), 359−367. (5) Scrosati, B.; Hassoun, J.; Sun, Y.-K. Lithium-Ion Batteries. A Look into the Future. Energy Environ. Sci. 2011, 4 (9), 3287. (6) Manthiram, A.; Fu, Y.; Chung, S.; Zu, C.; Su, Y. Rechargeable Lithium − Sulfur Batteries. Chem. Rev. 2014, 114, 11751−11787. (7) Yin, Y. X.; Xin, S.; Guo, Y.-G.; Wan, L. J. Lithium-Sulfur Batteries: Electrochemistry, Materials, and Prospects. Angew. Chem., Int. Ed. 2013, 52 (50), 13186−13200. (8) Rosenman, A.; Markevich, E.; Salitra, G.; Aurbach, D.; Garsuch, A.; Chesneau, F. F. Review on Li-Sulfur Battery Systems: An Integral Perspective. Adv. Energy Mater. 2015, 5 (16), 1500212. (9) 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. (10) Carbone, L.; Gobet, M.; Peng, J.; Devany, M.; Scrosati, B.; Greenbaum, S.; Hassoun, J. Comparative Study of Ether-Based Electrolytes for Application in Lithium-Sulfur Battery. ACS Appl. Mater. Interfaces 2015, 7 (25), 13859−13865. (11) Kim, J.; Lee, D.-J.; Jung, H.-G.; Sun, Y.-K.; Hassoun, J.; Scrosati, B. An Advanced Lithium-Sulfur Battery. Adv. Funct. Mater. 2013, 23 (8), 1076−1080. (12) Shin, H.-D.; Agostini, M.; Belharouak, I.; Hassoun, J.; Sun, Y.-K. High-Power Lithium Polysulfide-Carbon Battery. Carbon 2016, 96, 125−130. (13) Osada, N.; Bucur, C. B. C. B.; Aso, H.; Muldoon, J. The Design of Nanostructured Sulfur Cathodes Using Layer by Layer Assembly. Energy Environ. Sci. 2016, 9 (5), 1668−1673. (14) Patel, M. D.; Cha, E.; Kang, C.; Gwalani, B.; Choi, W. High Performance Rechargeable Li-S Batteries Using Binder-Free Large Sulfur-Loaded Three-Dimensional Carbon Nanotubes. Carbon 2017, 118, 120−126. (15) Hwang, J.-Y.; Kim, H. M.; Lee, S.-K.; Lee, J.-H.; Abouimrane, A.; Khaleel, M. A.; Belharouak, I.; Manthiram, A.; Sun, Y.-K. High-Energy, High-Rate, Lithium-Sulfur Batteries: Synergetic Effect of Hollow TiO2-
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpclett.7b02354. Experimental methods and operating conditions for the sulfurized-polyacrylonitrile cathode for lithium−sulfur batteries, additional figures (PDF) 5336
DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
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The Journal of Physical Chemistry Letters Webbed Carbon Nanotubes and a Dual Functional Carbon-Paper Interlayer. Adv. Energy Mater. 2016, 6 (1), 1501480. (16) Markevich, E.; Salitra, G.; Rosenman, A.; Talyosef, Y.; Chesneau, F.; Aurbach, D. Fluoroethylene Carbonate as an Important Component in Organic Carbonate Electrolyte Solutions for Lithium Sulfur Batteries. Electrochem. Commun. 2015, 60, 42−46. (17) Aurbach, D.; Weissman, I.; Zaban, A.; Chusid, O. Correlation between Surface Chemistry, Morphology, Cycling Efficiency and Interfacial Properties of Li Electrodes in Solutions Containing Different Li Salts. Electrochim. Acta 1994, 39 (1), 51−71. (18) Markevich, E.; Salitra, G.; Rosenman, A.; Talyosef, Y.; Chesneau, F.; Aurbach, D. The Effect of a Solid Electrolyte Interphase on the Mechanism of Operation of Lithium−sulfur Batteries. J. Mater. Chem. A 2015, 3 (39), 19873−19883. (19) Markevich, E.; Salitra, G.; Talyosef, Y.; Chesneau, F.; Aurbach, D. ReviewOn the Mechanism of Quasi-Solid-State Lithiation of Sulfur Encapsulated in Microporous Carbons: Is the Existence of Small Sulfur Molecules Necessary? J. Electrochem. Soc. 2017, 164 (1), A6244−A6253. (20) Rosenman, A.; Markevich, E.; Salitra, G.; Talyosef, Y.; Chesneau, F.; Aurbach, D. Facile Synthesis and Very Stable Cycling of Polyvinylidene Dichloride Derived Carbon: Sulfur Composite Cathode. J. Electrochem. Soc. 2016, 163 (9), A1829−A1835. (21) Pieczonka, N. P. W.; Borgel, V.; Ziv, B.; Leifer, N.; Dargel, V.; Aurbach, D.; Kim, J.-H.; Liu, Z.; Huang, X.; Krachkovskiy, S. A. Lithium Polyacrylate (LiPAA) as an Advanced Binder and a Passivating Agent for High-Voltage Li-Ion Batteries. Adv. Energy Mater. 2015, 5 (23), 1501008. (22) Markevich, E.; Salitra, G.; Aurbach, D. Fluoroethylene Carbonate as an Important Component for the Formation of an Effective Solid Electrolyte Interphase on Anodes and Cathodes for Advanced Li-Ion Batteries. ACS Energy Lett. 2017, 2, 1337−1345. (23) Markevich, E.; Salitra, G.; Chesneau, F.; Schmidt, M.; Aurbach, D. Very Stable Lithium Metal Stripping−Plating at a High Rate and High Areal Capacity in Fluoroethylene Carbonate-Based Organic Electrolyte Solution. ACS Energy Lett. 2017, 2, 1321−1326. (24) Wei, S.; Ma, L.; Hendrickson, K. E.; Tu, Z.; Archer, L. A. MetalSulfur Battery Cathodes Based on PAN-Sulfur Composites. J. Am. Chem. Soc. 2015, 137 (37), 12143−12152. (25) Li, Y.; Zeng, Q. R.; Gentle, I. R.; Wang, D.-W.; Gao, J.; Jiang, C. Y.; Leeuw, D. M. de; Wei, F.; Zhang, Q.; Kang, F. Y.; et al. Carboxymethyl Cellulose Binders Enable High-Rate Capability of Sulfurized Polyacrylonitrile Cathodes for Li−S Batteries. J. Mater. Chem. A 2017, 5 (11), 5460−5465. (26) Xu, Z.; Wang, J.; Yang, J.; Miao, X.; Chen, R.; Qian, J.; Miao, R. Enhanced Performance of a Lithium-Sulfur Battery Using a Carbonate-Based Electrolyte. Angew. Chem., Int. Ed. 2016, 55 (35), 10372−10375. (27) Konarov, A.; Gosselink, D.; Doan, T. N. L.; Zhang, Y.; Zhao, Y.; Chen, P. Simple, Scalable, and Economical Preparation of Sulfur-PAN Composite Cathodes for Li/S Batteries. J. Power Sources 2014, 259, 183−187. (28) Hara, T.; Konarov, A.; Mentbayeva, A.; Kurmanbayeva, I.; Bakenov, Z. High Mass-Loading of Sulfur-Based Cathode Composites and Polysulfides Stabilization for Rechargeable Lithium/Sulfur Batteries. Front. Energy Res. 2015, 3, 1. (29) Kim, J.-S.; Hwang, T. H.; Kim, B. G.; Min, J.; Choi, J. W. A Lithium-Sulfur Battery with a High Areal Energy Density. Adv. Funct. Mater. 2014, 24 (34), 5359−5367. (30) Mentbayeva, A.; Belgibayeva, A.; Umirov, N.; Zhang, Y.; Taniguchi, I.; Kurmanbayeva, I.; Bakenov, Z. High Performance Freestanding Composite Cathode for Lithium-Sulfur Batteries. Electrochim. Acta 2016, 217, 242−248. (31) Zhang, Y. Z.; Wu, Z. Z.; Pan, G. L.; Liu, S.; Gao, X. P. Microporous Carbon Polyhedrons Encapsulated Polyacrylonitrile Nanofibers as Sulfur Immobilizer for Lithium-Sulfur Battery. ACS Appl. Mater. Interfaces 2017, 9 (14), 12436−12444.
(32) Zhang, S. S. Understanding of Sulfurized Polyacrylonitrile for Superior Performance Lithium/sulfur Battery. Energies 2014, 7 (7), 4588−4600. (33) Yin, L.; Wang, J.; Lin, F.; Yang, J.; Nuli, Y. Polyacrylonitrile/ graphene Composite as a Precursor to a Sulfur-Based Cathode Material for High-Rate Rechargeable Li−S Batteries. Energy Environ. Sci. 2012, 5 (5), 6966. (34) Yin, L.; Wang, J.; Yang, J.; Nuli, Y. A Novel Pyrolyzed Polyacrylonitrile-sulfur@MWCNT Composite Cathode Material for High-Rate Rechargeable Lithium/sulfur Batteries. J. Mater. Chem. 2011, 21 (19), 6807. (35) Konarov, A.; Bakenov, Z.; Yashiro, H.; Sun, Y.-K.; Myung, S. T. Effect of Carbon-Sulphur Bond in a Sulphur/dehydrogenated Polyacrylonitrile/reduced Graphene Oxide Composite Cathode for Lithium-Sulphur Batteries. J. Power Sources 2017, 355, 140−146. (36) Magasinski, A.; Zdyrko, B.; Kovalenko, I.; Hertzberg, B.; Burtovyy, R.; Huebner, C. F.; Fuller, T. F.; Luzinov, I.; Yushin, G. Toward Efficient Binders for Li-Ion Battery Si-Based Anodes: Polyacrylic Acid. ACS Appl. Mater. Interfaces 2010, 2 (11), 3004−3010. (37) Zhang, Z.; Bao, W.; Lu, H.; Jia, M.; Xie, K.; Lai, Y.; Li, J. WaterSoluble Polyacrylic Acid as a Binder for Sulfur Cathode in LithiumSulfur Battery. ECS Electrochem. Lett. 2012, 1 (2), A34−A37. (38) Lee, S.; Kim, J.; Ku, B.-C.; Kim, J.; Joh, H.-I. Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization. Adv. Chem. Eng. Sci. 2012, 2 (2), 275−282. (39) Ming, J.; Ming, H.; Kwak, W.-J.; Shin, C.; Zheng, J.; Sun, Y.-K. The Binder Effect on an Oxide-Based Anode in Lithium and SodiumIon Battery Applications: The Fastest Way to Ultrahigh Performance. Chem. Commun. 2014, 50 (87), 13307−13310. (40) Komaba, S.; Shimomura, K.; Yabuuchi, N.; Ozeki, T.; Yui, H.; Konno, K. Study on Polymer Binders for High-Capacity SiO Negative Electrode of Li-Ion Batteries. J. Phys. Chem. C 2011, 115 (27), 13487− 13495. (41) Kim, H. M.; Sun, H.-H.; Belharouak, I.; Manthiram, A.; Sun, Y.K. An Alternative Approach to Enhance the Performance of High Sulfur-Loading Electrodes for Li−S Batteries. ACS Energy Lett. 2016, 1 (1), 136−141. (42) Kang, H.-S.; Sun, Y.-K. Freestanding Bilayer Carbon-Sulfur Cathode with Function of Entrapping Polysulfide for High Performance Li-S Batteries. Adv. Funct. Mater. 2016, 26 (8), 1225−1232. (43) Kang, H.-S.; Park, E.; Hwang, J.-Y.; Kim, H.; Aurbach, D.; Rosenman, A.; Sun, Y.-K. A Scaled-Up Lithium (Ion)-Sulfur Battery: Newly Faced Problems and Solutions. Adv. Mater. Technol. 2016, 1 (6), 1600052.
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DOI: 10.1021/acs.jpclett.7b02354 J. Phys. Chem. Lett. 2017, 8, 5331−5337
