Solid State Sciences 95 (2019) 105924
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ZnO/carbon nanotube/reduced graphene oxide composite ﬁlm as an eﬀective interlayer for lithium/sulfur batteries
Zhenghao Suna, Yaping Guoa, Baoe Lia,∗∗, Taizhe Tanb, Yan Zhaoa,∗ a b
School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China Synergy Innovation Institute of GDUT, Heyuan, Guangdong Province, China
A R T I C LE I N FO
A B S T R A C T
Keywords: Lithium/sulfur batteries ZnO/carbon nanotube/reduced graphene oxide (ZnO/CNT/RGO) composite Interlayer Electrochemical performance
The application of lithium/sulfur (Li/S) batteries is negatively aﬀected by the insulation of sulfur and large volumetric change during the cycles as well as the polysulﬁdes dissolution. To solve the above problems, we fabricated a composite interlayer for Li/S batteries using ZnO nanocrystals anchored on connected carbon nanotube and graphene. The preparation of ZnO/carbon nanotube/reduced graphene oxide (ZnO/CNT/RGO) composite ﬁlm was inspired from the combination of a one-step sol-gel synthetic technique and vacuum-assisted ﬁltration. The ZnO/CNT/RGO interlayer showed eﬀective adsorption of polysulﬁdes during diﬀusion experiments. This ZnO/CNT/RGO interlayer can eﬃciently increase sulfur utilization by immobilizing soluble intermediate polysulﬁdes. When used as a composite interlayer in Li/S batteries, an impressive high capacity of 768 mAh g−1 at 0.2C was achieved after 150 cycles and improved rate performance of 597 mAh g−1 at 2C was obtained. This study oﬀers a facile method to improve the electrochemical performance of the Li/S batteries.
1. Introduction With the rapid development of energy systems, high-capacity sustainable batteries are becoming in high demand. Lithium/sulfur (Li/S) batteries have become popular in the energy storage ﬁeld because of their high theoretical energy density equal to ∼2600 Wh kg−1, environmental benignity of sulfur, low cost, and natural abundance . However, several disadvantages limit their commercial applications. Low electronic conductivity of sulfur and the discharge products can cause low active material utilization [2,3]. A more serious issue is associated with spontaneous formation of polysulﬁdes (Li2Sx, 4 ≤ x ≤ 8) as discharge by-products and their diﬀusion into the electrolytes . These polysulﬁdes could dissolve through the separator and ﬁnally deposit on the surface of the Li metal anode, causing the low sulfur utilization, rapid capacity fading and low coulombic eﬃciency [5,6]. To overcome this problem, researchers typically use various cathode materials such as conductive polymers, carbon-based materials and metal oxides . However, a complicated process and strict control of reaction conditions are usually necessary to synthesize the above sulfur based composite cathodes . Another increasingly popular strategy is applying an interlayer to place between the separator and the sulfur cathode . Such functional interlayer barrier restrains polysulﬁdes migration to the Li anode as well as works as the upper-current ∗
collector, improving overall utilization of sulfur . Diﬀerent kind of carbon materials have been widely applied in functional interlayers using vacuum ﬁltration . For example, reduced graphene oxide and carbon nanotubes can form a highly conductive, free-standing interlayer by vacuum ﬁltration [12,13]. Such carbon-based interlayers can inhibit polysulﬁdes diﬀusion and improved electrochemical performances of Li/S batteries . Although a substantial progress has been made, the physical barrier made from carbon materials with weak adsorption ability to polysulﬁdes cannot totally alleviate the shuttle eﬀect of dissolved polysulﬁdes . With this concern, previous studies have also used metal oxides as sulfur hosts to chemically bind polysulﬁdes, such as TiO2, MnO2 and V2O5 [16–19]. Among all possible candidates, ZnO has advantages of environmental friendliness, nature abundant, and polar nature, which have used as sulfur immobilizer for Li/S batteries . One example of ZnO application in the interlayer for Li/S batteries is done by Yu et al. . They designed an interlayer composed of reduced graphene oxide (RGO) with ALD-deposited ZnO acting as a barrier inhibiting polysulﬁdes diﬀusion. Inspired by this strategy, we propose the fabrication of free-standing ZnO/carbon nanotube/reduced graphene oxide (ZnO/CNT/RGO) composite ﬁlm acting as a conductive interlayer for Li/S batteries. The ZnO nanocrystals were homogeneously anchored on the CNT/RGO
Corresponding author. Corresponding author. E-mail addresses: [email protected]
(B. Li), [email protected]
https://doi.org/10.1016/j.solidstatesciences.2019.06.013 Received 2 March 2019; Received in revised form 27 May 2019; Accepted 28 June 2019 Available online 29 June 2019 1293-2558/ © 2019 Elsevier Masson SAS. All rights reserved.
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Fig. 1. Schematic of the ZnO/CNT/RGO interlayer preparation.
2.3. Cell assembly and electrochemical characterization
matrix via sol-gel method, and the resulting composite was vacuumﬁltered to form a free-standing thin ﬁlm as an eﬃcient interlayer for Li/ S batteries. As expected, this interlayer could enable improving the electrical conductivity and alleviating the shuttle eﬀect, leading to the much-improved electrochemical performance.
The sulfur cathode composite S/RGO was prepared by previous reports . Mixture containing 80 wt% of S/RGO composite, 10 wt% of ketjen black (purchased from Shanghai Huzheng Nano Technology Co.) and 10 wt% of polyvinylidene ﬂuoride (PVDF) binder (99.9%, purchased from Aladdin Co., China) was added to N-methylpyrrolidinone. Formed slurry was coated on Al foils and dried at 60 °C in vacuum for 12 h. The sulfur cathode was punched into circular disks with a diameter of 12 mm and the sulfur loading at 1.7 mg cm−2. The high sulfur loading S/RGO electrode was controlled at 4.3 mg cm−2 by adjusting the coating thickness. We used 1 mol/L of lithium bis(tri-ﬂuoromethanesulfonyl)imide (LiTFSI, purchased from Sigma Aldrich) dissolved in dimethoxy ethane and 1,3-dioxolane with 1:1 vol ratio as electrolyte. For each electrode, around 45 and 40 μL electrolyte (the ES ratio was 20:1) was added in the Li/S batteries with and without ZnO/CNT/RGO interlayer, respectively. Coin cells (CR2025) were assembled in Ar-ﬁlled glove box (Mbraun, Unilab, Germany) with S/RGO composite cathode, the ZnO/ CNT/RGO ﬁlms, Celgard 2400 separator and metallic Li foil as an anode. Properties of the prepared S/RGO composites were consistent with Galvanostatic charge/discharge measurements were performed at room temperature using multichannel battery tester (BTS-5V5mA, Neware) in the 1.5–3.0 V range (vs Li+/Li electrode).
2. Experimental 2.1. ZnO/CNT/RGO composite interlayer fabrication Fabrication procedure of the ZnO/CNT/RGO composite interlayer was shown in Fig. 1. First, 2 g of zinc acetate (Zn(CH3COO)2, ≥99%, Sigma-Aldrich) was dissolved in 130 mL of ethanol. Then 0.7 g of 7 wt% CNT dispersion (from Nanjing Xianfeng) and 10 g of 0.5 wt% of RGO aqueous suspension (purchased from Chengdu Organic Chemicals) were added under constant stirring. Subsequently, 60 mL of ethanol solution containing 1.5 g of KOH (≥95%, Sigma-Aldrich) was injected. The mixture was stirred for 24 h at 40 °C. ZnO/CNT/RGO ﬁlms were fabricated using vacuum ﬁltration of the hybrid dispersion using a 100 nm ﬁlter (in diameter). The ﬂexible ﬁlms became detached after vacuum drying for 12 h at 60 °C. The mass loading of ZnO/CNT/RGO composite interlayer with a typical density of 0.85 mg cm−2 with a diameter of 19 mm. Consequently, the weight of the ZnO/CNT/RGO composite interlayer was 2.4 mg.
3. Results and discussion 2.2. Material characterization Crystal structures of pure ZnO and ZnO/CNT/RGO composites were investigated by XRD analysis and their corresponding XRD peaks are shown in Fig. 2a. Peaks corresponding to the (100), (002), (101), (102), (110), (103), (200), (112), (201) and (202) planes of hexagonal ZnO dominate in both XRD spectra. Lattice parameters determined from these peaks are a = 0.3257 nm and c = 0.52156 nm (using JCPDS card No. 36-1451) . The broad peak observed at 2θ∼25° corresponds to the carbon from the ZnO/CNT/RGO composite . Thus, the composite consisted of carbon and well crystallized ZnO. Peaks corresponding to the (200), (112) and (201) planes of ZnO in the XRD pattern of the ZnO/CNT/RGO composite were obscured by the overlapping
Crystal structures were analyzed by X-ray powder diﬀraction (XRD) performed using Rigaku Ultima IV diﬀractometer with Cu-Ka radiation. Thermal gravimetric analysis (TGA, Henven HTG-1) was performed in ﬂowing air at 10° min−1 heating rate. The N2 adsorption/desorption tests were analyzed by Brunauer-Emmett-Teller (BET, Gold APP V-Sorb 2800P). Sample morphologies were examined using scanning electron microscopy (SEM, Hitachi S–3400 N) and a transmission electron microscopy (TEM, JEOL JEM-2010). Surface compositions were analyzed by X-ray photoelectron spectroscopy (XPS) using Thermo Scientiﬁc KAlpha XPS spectrometer. 2
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Fig. 2. (a) XRD analysis of pure ZnO and ZnO/CNT/RGO composites. (b) TGA curve of the ZnO/CNT/RGO composite in air.
peaks of CNT and RGO. To determine ZnO content in the ZnO/CNT/ RGO composite, we performed TGA analysis (see Fig. 2b). Weight loss in the 25–100 °C range is attributed to the water loss. Carbon started decomposing at ∼150 °C completely disappearing at ∼755 °C. When the temperature is further increased to 755 °C, the loss of weight is negligible due to the total loss of carbon material in the ZnO/CNT/RGO composite. The remaining weight was attributed to ZnO in the ZnO/ CNT/RGO and it accounted for 68.4% of the total initial weight. A large amount of ZnO can improve the ion transport eﬃciency and adsorb polysulﬁdes, and the carbon material improves the conductivity of the ﬁlm . The speciﬁc surface area and pore size distribution of ZnO/CNT/ RGO composite were evaluated based on nitrogen absorption-desorption experiment and using the BET isotherm method. The speciﬁc surface area of ZnO/CNT/RGO composite is about 94.8 m2 g−1, the corresponding adsorption-desorption curve is shown in Fig. 3a. The Barret-Joyner-Halenda (BJH) desorption pore size distribution was given in Fig. 3b. ZnO/CNT/RGO composite exhibited a micropores and macropores structures which facilitate the adsorption of sulfur and polysulﬁdes in the electrolyte . Morphology and crystalline structure of the ZnO/CNT/RGO composite were analyzed by SEM and TEM. Fig. 4a shows SEM image of the ZnO/CNT/RGO composite. Numerous CNTs attached to the graphene surface can be clearly seen. These CNTs formed a three-dimensional network. ZnO nanoparticles were closely anchored on the surfaces of both graphene and CNTs. ZnO/CNT/RGO as interlayer in Li/S batteries can maintain good cycling stability of a battery because of its good mechanical strength and ﬂexibility (see insert in Fig. 4a). Fig. 4b shows TEM image of the ZnO/CNT/RGO composite. ZnO nanoparticles 50–100 nm in size look homogeneously anchored to the RGO and CNT. Using high resolution transmission electron microscope (HRTEM), the lattice fringe scan be clearly seen, and the corresponding distances
Fig. 4. (a) SEM image of the ZnO/CNT/RGO composite. Insert shows a photograph of the ZnO/CNT/RGO composite ﬁlm. (b) TEM and (c) HRTEM images as well as (d) SAED patterns of the ZnO/CNT/RGO composite.
are ∼ 0.262 and 0.512 nm (see Fig. 4c). These spacings agree well with the interplanar distances for (102) and (105) planes of ZnO . The lattice fringes (shown in Fig. 4d) with 0.178, 0.192, 0.202, 0.262, 0.308,0.339 and 0.355 nm spacings correspond to (100), (002), (101), (102), (110), (103) and (200) planes of ZnO, respectively. The SAED pattern in Fig. 4d demonstrates polycrystalline ZnO with homogeneous diﬀraction rings, conﬁrming presence of ZnO nanocrystals in the ZnO/ CNT/RGO composite. The XPS spectra of the ZnO/CNT/RGO composite interlayer after
Fig. 3. (a) N2 adsorption-desorption isotherm loops of ZnO/CNT/RGO composites. (b) Pore size distributions of ZnO/CNT/RGO composites. 3
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Fig. 5. XPS analysis of the ZnO/CNT/RGO composite interlayer after cycling.
Fig. 7a shows ﬁrst three charge/discharge 0.2C cycles of Li/S battery with ZnO/CNT/RGO composite interlayer. Two typical potential platforms ascribed to the two stages of sulfur electrochemical redox reaction can be observed. The ﬁrst discharge plateau at ∼2.3 V is related to the formation of soluble lithium polysulﬁdes (Li2Sx, x ≥ 4) . The second plateau at ∼2.1 V is associated with the further reduction of high-order polysulﬁdes to Li2S2 and Li2S . Such stable discharge platform indicated that Li/S batteries equipped with ZnO/CNT/RGO composite interlayer had a smooth discharge process with higher initial discharge capacity. The advantage of the ZnO/CNT/RGO composite interlayer for Li/S batteries was further demonstrated during the cycling performance of the cells at 0.2C (see Fig. 7b). Li/S batteries with ZnO/CNT/RGO composite interlayer delivered initial discharge capacity equal to 1061 mAh g−1. After 150 cycles, discharge capacity of this battery dropped to 768 mAh g−1. However, Li/S batteries without interlayer only delivered 981 mAh g−1 of the initial discharge capacity, and after 150 cycles capacity dropped to 608 mAh g−1. Thus, our ZnO/CNT/RGO composite interlayer absorbed polysulﬁdes and inhibited reactions between polysulﬁdes and lithium metal. Reversible capacities of Li/S batteries with ZnO/CNT/RGO composite interlayer equal to 938, 840, 723 and 597 mAh g−1 were achieved at 0.2, 0.5, 1 and 2C, respectively (Fig. 7c). The cells were able to recover to the 903 mAh g−1 after returning to 0.2C cycling demonstrating excellent reversibility. However, at 2C current density, conventional Li/S battery could only provide a discharge capacity equal to 403 mAh g−1. These results demonstrate that the ZnO/CNT/RGO composite interlayer was immobilizing polysulﬁdes during the cycling, deactivating dissolved polysulﬁdes . We
100 cycles were shown in Fig. 5. C1s spectrum of ZnO/CNT/RGO composite (shown in Fig. 5a) displays diﬀerent peaks. C–S peak at the 285.9 eV demonstrates that sulfur and polysulﬁdes are blocked in the ZnO/CNT/RGO composite interlayer . Deconvoluted XPS spectrum of the S2p peak (shown in Fig. 5b) shows distinguishable peaks and corresponding to the diﬀerent chemical environment of sulfur atoms bonded to ZnO/CNT/RGO composite interlayer. Thus, certain chemical bonds formed between S and ZnO/CNT/RGO composite interlayer after cycling. XPS results demonstrated S–C bonds and Zn–S bonds; thus, we believe that the ZnO/CNT/RGO composite interlayer can eﬀectively immobilize polysulﬁdes by chemically binding with them . To demonstrate that ZnO/CNT/RGO composite interlayer can effectively inhibit polysulﬁdes diﬀusion, we photographed the polysulﬁdes diﬀusion evolution in H-shaped test tubes during diﬀusion experiment (see Fig. 6). Commercial separator and ZnO/CNT/RGO composite interlayer were placed into H-shaped glass tubes. Right and left sides of the H-shaped glass tubes were ﬁlled with Li2S6 solution in tetrahydrofuran (THF) and pure THF, respectively . Because of the concentration gradient, Li2S6 diﬀused through the separator from the left side to the right side, causing a color change (see Fig. 6a). In comparison, the H-shaped glass tubes were equipped with ZnO/CNT/ RGO composite interlayer, in Fig. 6b. After 8 h, the color change of the THF solution on the right side was slight, indicating that almost no Li2S6 passed through the ZnO/CNT/RGO composite interlayer. Beneﬁting from the adsorption of polysulﬁdes by ZnO/CNT/RGO composite interlayer, Li/S batteries can exhibit excellent cycle performance. To further clarify eﬀect of ZnO/CNT/RGO composite interlayer on the battery performance, various electrochemical tests were conducted.
Fig. 6. Photographs of the polysulﬁdes diﬀusion process conducted in H-shaped test tubes (a) with and (b) without ZnO/CNT/RGO composite interlayer. 4
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Fig. 7. (a) Charge and discharge curves of the Li/S batteries with the ZnO/CNT/RGO composite interlayer at 0.2C. (b) Cycling performance of the Li/S batteries at 0.2C rate with and without the ZnO/ CNT/RGO composite interlayer. (c) Rate capability of the Li/S batteries with and without the ZnO/CNT/ RGO composite interlayer at diﬀerent current densities. (d) Cycling performance of the Li/S batteries at 0.2C rate with a high sulfur loading.
advantages of the ZnO/CNT/RGO composite interlayer under high sulfur loading, the cycling performance with a high sulfur loading of 4.3 mg cm−2 were measured at 0.2C. As shown in Fig. 7d, the Li/S batteries with ZnO/CNT/RGO composite interlayer exhibited a high initial discharge capacity of 901 mAh g−1 and remained at 719 mAh g−1 after 50 cycles, with a high initial areal capacity 3.9 mAh cm−2. The Li/S batteries with the ZnO/CNT/RGO composite interlayer with such high areal capacity improve the practical application of Li/S batteries. In order to further prove that the ZnO/CNT/RGO composite interlayer can eﬀectively capture polysulﬁdes, SEM and elemental mapping images of the ZnO/CNT/RGO composite interlayer after cycling were shown in Fig. 8. Compared to the microstructure image of the ZnO/ CNT/RGO composite interlayer before cycling (Fig. 8a), the ZnO/CNT/ RGO composite interlayer after cycling (Fig. 8c) covered with redistributed sulfur or polysulﬁdes. The eﬀective inhibition of the polysulﬁdes is further conﬁrmed by the elemental mapping. As shown in Fig. 8b, the interlayer before cycling exhibits a few sulfur element distributions due to the signal noise. However, a signiﬁcant elemental distribution of sulfur was shown in the ZnO/CNT/RGO composite interlayer after cycling (Fig. 8d), which suggests that the interlayer can eﬀective block the migration of polysulﬁdes. In order to verify the function of ZnO/CNT/RGO composite interlayer on suppress the growth of Li dendrites, Li–Li symmetrical batteries were assembly and measured at an ultrahigh current density of
Fig. 8. SEM image of ZnO/CNT/RGO composite interlayer (a) before and (c) after cycling. EDX mapping of Zn, O, C and S elemental distributions in the ZnO/CNT/RGO composite interlayer (b) before and (d) after cycling.
also believe that ZnO/CNT/RGO composite interlayer could work as an upper current collector and reduce the charge-transfer resistance improving rate capability of the Li/S batteries. In order to verify the
Fig. 9. Voltage-time curves of Li–Li symmetric batteries with and without ZnO/CNT/RGO composite interlayer at a current density of 5 mA cm−2. 5
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Table 1 Comparison of the electrochemical performance of previous reports with our work. Sample
Sulfur loading (content or areal loading)
Initial capacity (mAh g−1, at n C)
Final capacity (mAh g−1) (after cycles)
High Rate performance (mAh g−1, at n C)
RGO/AC interlayer PP/GO/Naﬁon ternary separator PrNPs Carbon layer-coated separator GO/CNT ﬁlms ZnO/CNT/RGO interlayer
58.2% 1.2 mg cm−2
1078 mAh g−1 (0.1C) 1090 mAh g−1 (0.1C)
655 mAh g−1 (100 th) Not mentioned
348 mAh g−1 (1.5C) 667 mAh g−1 (2C)
70%, 1.1 mg cm−2 60%, 1.6 mg cm−2 1.0 mg cm−2 68.3%, 1.7 mg cm−2
986 mAh g−1 (0.2C) 1090 mAh g−1 (0.5C) 1370 mAh g−1 (0.2C) 1061 mAh g−1 (0.2C)
695 mAh 778 mAh 787 mAh 768 mAh
5 mA cm−2. As shown in Fig. 9, in the Li–Li symmetrical batteries with the ZnO/CNT/RGO composite interlayer, Li stripping and plating exhibits a low and stable over potential of less than 0.2 V for over 200 h, indicating a uniform Li deposition and a stable SEI layer. In comparison, the Li–Li symmetrical batteries without ZnO/CNT/RGO composite interlayer exhibits an over potential increases from 0.35 V to 0.6 V which suggests the uncontrollable Li dendrite growth and the damage of SEI layer [34,35]. To compare the electrochemical performance of these interlayers or modiﬁed separators, further comparison among these Li/S batteries are carried out as shown in Table .1 [36–40]. It is signiﬁcant note that the cycling performance of the Li/S batteries with ZnO/CNT/RGO composite interlayer exhibits a good cycle performance and rate capability.
4. Conclusions We report a ZnO/CNT/RGO ﬁlm prepared by sol-gel technique and vacuum ﬁltration to realize the physical blocking and chemical trapping dual function of polysulﬁdes in Li/S batteries. The ZnO nanocrystals uniformly anchored on the RGO achieve eﬀective adsorption of polysulﬁdes, and the interwoven CNT network improves the mechanical strength and the conductivity of ZnO/CNT/RGO ﬁlm. Furthermore, the embedded ZnO/CNT/RGO ﬁlm acts as a conductive upper current collector, which reduces the polarization of the Li/S batteries, increases the discharge speciﬁc capacity and achieve a stable and reversible electrochemical process. Li/S batteries with ZnO/CNT/RGO interlayer had high initial discharge capacity of 1061 mAh g−1 and a reversible capacity of 768 mAh g−1, which retained after 150 cycles at a rate of 0.2C. Meanwhile, Li/S batteries with ZnO/CNT/RGO interlayer show a high speciﬁc capacity of 597 mAh g−1 at 2C rate. Thus, we combined beneﬁts of both ZnO and carbon materials and prepared composite ﬁlm to improve electrochemical performance of Li/S batteries. The Li/S batteries with ZnO/RGO/CNT interlayer deliver a high initial areal capacity of 3.9 mAh cm−2, improving the potential of practical applications. This simple method can help to further promote development of the Li/S batteries technology.
The authors gratefully acknowledge the support by the Natural Science Foundation of Hebei Province of China (Project No. E2017202032); Technology Foundation for returned overseas Chinese scholars (No.C2015003038); the Program for the Outstanding Young Talents of Hebei Province; Cultivation Project of National Engineering Technology Center [Grant No. 2017B090903008].
References   A. Manthiram, Y.Z. Fu, Y.S. Su, Challenges and prospects of lithium-sulfur batteries, Acc. Chem. Res. 46 (2013) 1125–1134, https://doi.org/10.1021/ar300179v.  L. Li, S. Basu, Y.P. Wang, Z.Z. Chen, P. Hundekar, B.W. Wang, J. Shi, Y.F. Shi, S. Narayanan, N. Koratkar, Self-heating–induced healing of lithium dendrites, Science 359 (2018) 1513–1516, https://doi.org/10.1126/science.aap8787.  H.F. Shi, S.Z. Niu, W. Lv, G.M. Zhou, C. Zhang, Z.H. Sun, F. Li, F.Y. Kang, Q.H. Yang, Easy fabrication of ﬂexible and multilayer nanocarbon-based cathodes with a high
g−1 g−1 g−1 g−1
(200 th) (100 th) (100 th) (150th)
753 mAh 700 mAh 469 mAh 597 mAh
g−1 g−1 g−1 g−1
(2C) (2C) (2C) (2C)
   Our work
unreal sulfur loading by electrostatic spraying for lithium-sulfur batteries, Carbon 138 (2018) 18–25, https://doi.org/10.1016/j.carbon.2018.05.077. Y.S. Wu, C.M. Xu, J.X. Guo, Q.M. Su, G.H. Du, J. Zhang, Enhanced electrochemical performance by wrapping graphene on carbon nanotube/sulfur composites for rechargeable lithium-sulfur batteries, Mater. Lett. 137 (2014) 277–280, https://doi. org/10.1016/j.matlet.2014.09.044. G.M. Zhou, E. Paek, G.S. Hwang, A. Manthiram, Long-life Li/polysulphide batteries with high sulphur loading enabled by lightweight three-dimensional nitrogen/sulphur-codoped graphene sponge, Nat. Commun. 6 (2015), https://doi.org/10.1038/ ncomms8760 7760-7760. G.M. Zhou, L. Li, D.W. Wang, X.Y. Shan, S.F. Pei, F. Li, H.M. Cheng, A ﬂexible sulfur-graphene-polypropylene separator integrated electrode for advanced Li-S batteries, Adv. Mater. 27 (2015) 641–647, https://doi.org/10.1002/adma. 201404210. M. Liu, X.Y. Qin, Y.B. He, B.H. Li, F.Y. Kang, Recent innovative conﬁgurations in high-energy lithium-sulfur batteries, J. Mater. Chem. A. 5 (2017) 5222–5234, https://doi.org/10.1039/C7TA00290D. F.X. Yin, X.Y. Liu, Y.G. Zhang, Y. Zhao, A. Menbayeva, Z. Bakenov, X. Wang, Welldispersed sulfur anchored on interconnected polypyrrole nanoﬁber network as high performance cathode for lithium-sulfur batteries, Solid State Sci. 396 (2017) 542–550, https://doi.org/10.1016/j.jpowsour.2018.06.040. Y.G. Zhang, Y. Zhao, A. Konarov, Z. Li, P. Chen, Eﬀect of mesoporous carbon microtube prepared by carbonizing the poplar catkin on sulfur cathode performance in Li/S batteries, J. Alloy. Comp. 619 (2015) 298–302, https://doi.org/10.1016/j. jallcom.2014.09.055. Z. Liang, G. Zheng, W. Li, Z.W. Seh, H. Yao, K. Yan, D. Kong, Y. Cui, Sulfur cathodes with hydrogen reduced titanium dioxide inverse opal structure, ACS Nano 8 (2014) 5249–5256, https://doi.org/10.1021/nn501308m. M. Liu, Q. Li, X.Y. Qin, G.M. Liang, W.J. Han, D. Zhou, Y.B. He, B.H. Li, F.Y. Kang, Suppressing self-discharge and shuttle eﬀect of lithium-sulfur batteries with V2O5decorated carbon nanoﬁber interlayer, Small 13 (2017) 1602539, https://doi.org/ 10.1002/smll.201602539. J.Y. Hwang, H.M. Kim, S. Lee, J.H. Lee, A. Abouimrane, M.A. Khaleel, L. Belharouak, A. Manthiram, Y. Sun, High-energy, high-rate, lithium-sulfur batteries: synergetic eﬀect of hollow TiO2-webbed carbon nanotubes and a dual functional carbon-paper interlayer, Adv. Energy Mater. 6 (2016) 1501480, https:// doi.org/10.1002/aenm.201501480. L. Ni, Z. Wu, G. Zhao, C. Sun, Q. Zhou, X. Gong, G. Diao, Core-Shell structure and interaction mechanism of gamma-MnO2 coated sulfur for improved lithium-sulfur batteries, Small 13 (2017) 201603466, https://doi.org/10.1002/smll.201603466. G.M. Zhou, K. Liu, Y.C. Fan, M.Q. Yuan, B.F. Liu, W. Liu, F.F. Shi, Y.Y. Liu, W. Chen, J. Lopez, D. Zhuo, J. Zhao, Y. Tsao, X.Y. Huang, Q.F. Zhang, Y. Cui, An aqueous inorganic polymer binder for high performance lithium-sulfur batteries with ﬂameretardant properties, ACS Cent. Sci. 4 (2018) 260–267, https://doi.org/10.1021/ acscentsci.7b00569. K. Liao, P. Mao, N. Li, M. Han, J. Yi, P. He, Y. Sun, H. Zhou, Stabilization of polysulﬁdes via lithium bonds for Li-S batteries, J. Mater. Chem. A. 4 (2016) 5406–5409, https://doi.org/10.1039/c6ta00054a. X. Liu, J.Q. Huang, Q. Zhang, L.Q. Mai, Nanostructured metal oxides and sulﬁdes for lithium-sulfur batteries, Adv. Mater. 29 (2017) 1601759, https://doi.org/10. 1002/adma.201601759. H.M. Song, C. Zuo, X.Q. Xu, Y.X. Wan, Lj Wang, D.S. Zhou, Z.J. Chen, A thin TiO2 NTs/GO hybrid membrane applied as an interlayer for lithium-sulfur batteries, RSC Adv. 8 (2018) 429–434, https://doi.org/10.1039/c7ra10858c. L.B. Ni, G.J. Zhao, G. Yang, G.S. Niu, M. Chen, G.W. Diao, Dual core-shell-structured [email protected]
@MnO2 nanocomposite for highly stable lithium-sulfur batteries, ACS Appl. Mater. Interfaces 9 (2017) 34793–34803, https://doi.org/10.1021/acsami. 7b07996. R. Carter, L. Oakes, N. Muralidharan, A.P. Cohn, A. Douglas, C.L. Pint, Polysulﬁdes anchoring mechanism revealed by atomic layer deposition of V2O5 and sulfur-ﬁlled carbon nanotubes for lithium-sulfur batteries, ACS Appl. Mater. Interfaces 9 (2017) 7185–7192, https://doi.org/10.1021/acsami.6b16155. R.L. Yang, H.W. Du, Z.Q. Lin, L.L. Yang, H. Zhu, H. Zhang, Z.K. Tang, X.C. Cui, ZnO nanoparticles ﬁlled tetrapod-shaped carbon shell for lithium-sulfur batteries, Carbon 141 (2019) 258–265, https://doi.org/10.1016/j.carbon.2018.09.060. M.P. Yu, A.J. Wang, F.Y. Tian, H.Q. Song, Y.S. Wang, C. Li, J.D. Hong, G.Q. Shi, Dual-protection of a graphene-sulfur composite by a compact graphene skin and an atomic layer deposited oxide coating for a lithium-sulfur battery, Nanoscale 7 (2015) 5292–5298, https://doi.org/10.1039/c5nr00166h. Y.G. Zhang, L.C. Sun, H.P. Li, T.Z. Tan, J.D. Li, Porous three-dimensional reduced
Solid State Sciences 95 (2019) 105924
Z. Sun, et al.
1802130, https://doi.org/10.1002/aenm.201802130.  J.Q. Huang, T.Z. Zhuang, Q. Zhang, H.J. Peng, C.M. Chen, F. Wei, Permselective graphene oxide membrane for highly stable and anti-self-discharge lithium-sulfur batteries, ACS Nano 9 (2015) 3002–3011, https://doi.org/10.1021/nn507178a.  Z.F. Zhou, T.K. Zhao, X.G. Lu, H.Q. Cao, X. Zha, Z.F. Zhou, Functionalized polyimide separators enable high performance lithium sulfur batteries at elevated temperature, J. Power Sources 396 (2018) 542–550, https://doi.org/10.1016/j. jpowsour.2018.06.040.  Y.Y. Peng, Z.P. Wen, C.Y. Liu, J. Zeng, Y.H. Wang, J.B. Zhao, Reﬁning interfaces between electrolyte and both electrodes with carbon nanotube paper for highloading lithium sulfur batteries, ACS Appl. Mater. Interfaces 11 (2019) 6986–6994, https://doi.org/10.1021/acsami.8b19866.  Y.B. He, Z. Chang, S. C Wu, Y. Qiao, S.Y. Bai, K.Z. Jiang, P. He, H.S. Zhou, Simultaneously inhibiting lithium dendrites growth and polysulﬁdes shuttle by a ﬂexible MOF-based membrane in Li-S batteries, Adv. Energy Mater. 8 (2018) 1802130, https://doi.org/10.1002/aenm.201802130.  H.P. Li, L.C. Sun, Y.G. Zhang, T.Z. Tan, G.K. Wang, Z. Bakenov, Enhanced cycle performance of Li/S battery with the reduced graphene oxide/activated carbon functional interlayer, Journal of Energy Chemistry 6 (2017) 1276–1281, https:// doi.org/10.1016/j.jechem.2017.09.009.  T.Z. Zhuang, J.Q. Huang, H.J. Peng, L.Y. He, X.B. Chen, C.M. Chen, Q. Zhang, Rational integration of polypropylene/graphene oxide/naﬁon as ternary-layered separator to retard the shuttle of polysulﬁdes for lithium-sulfur batteries, Small 3 (2016) 381–389, https://doi.org/10.1002/smll.201503133.  L. Kong, X. Chen, B.Q. Li, H.J. Peng, J.Q. Huang, J. Xie, Q. Zhang, A bifunctional perovskite promoter for polysulﬁde regulation toward stable lithium-sulfur batteries, Adv. Mater. 30 (2018) 1705219, https://doi.org/10.1002/adma.201705219.  Z.Y. Zhang, Y.Q. Lai, Z.A. Zhang, J. Li, A functional carbon layer-coated separator for high performance lithium sulfur batteries, Solid State Ionics 278 (2015) 166–171, https://doi.org/10.1016/j.ssi.2015.06.018.  J.Q. Huang, Z.L. Xu, S. Abouali, M.A. Garakani, J. Kim, Porous graphene oxide/ carbon nanotube hybrid ﬁlms as interlayer for lithium-sulfur batteries, Carbon 99 (2016) 624–632, https://doi.org/10.1016/j.carbon.2015.12.081.
graphene oxide for high-performance lithium-sulfur batteries, J. Alloy. Comp. 739 (2018) 290–297, https://doi.org/10.1016/j.jallcom.2017.12.294. X. Gu, C.J. Tong, B. Wen, L.M. Liu, C. Lai, S.Q. Zhang, Ball-milling synthesis of [email protected]
/carbon nanotubes and Ni (OH)(2)@sulphur/carbon nanotubes composites for high-performance lithium-sulphur batteries, Electrochim. Acta 196 (2016) 369–376, https://doi.org/10.1016/j.electacta.2016.03.018. H.P. Li, Y.Q. Wei, Y. Zhao, Y.G. Zhang, F.X. Yin, C.W. Zhang, Z. Bakenov, Simple one-pot synthesis of hexagonal ZnO nanoplates as anode material for lithium-ion batteries, J. Nanomater. (2016) 4675960, https://doi.org/10.1155/2016/4675960. Y.L. Li, Y.T. Zhao, G.S. Huang, B.R. Xu, B. Wang, R.B. Pan, C.L. Men, Y.F. Mei, ZnO nanomembrane/expanded graphite composite synthesized by atomic layer deposition as binder-free anode for lithium ion batteries, ACS Appl. Mater. Interfaces 9 (2017) 38522–38529, https://doi.org/10.1021/acsami.7b11735. Y.M. Zhang, Y.T. Wu, H.R. Ding, Y. Yan, Z.B. Zhou, Y. Ding, N. Liu, Sealing Zno nanorods for deeply rechargeable high-energy aqueous battery anodes, Nanomater. Energy 53 (2018) 666–674, https://doi.org/10.1016/j.nanoen.2018.09.021. J. Zhang, P. Gu, J. Xu, H.G. Xue, H. Pang, High performance of electrochemical lithium storage batteries: ZnO-based nanomaterials for lithium-ion and lithiumsulfur batteries, Nanoscale 44 (2016) 18578–18595, https://doi.org/10.1039/ c6nr07207k. J. Schuster, G. He, B. Mandlmeier, T. Yim, K.T. Lee, T. Bein, L.F. Nazar, Spherical ordered mesoporous carbon nanoparticles with high porosity for lithium-sulfur batteries, Angew. Chem. Int. Ed. 51 (2012) 3591–3595, https://doi.org/10.1002/ anie.201107817. Q. Pang, D. Kundu, M. Cuisinier, L.F. Nazar, Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries, Nat. Commun. 5 (2014) 4759, https://doi.org/10.1038/ncomms5759. F. Pei, L.L. Lin, A. Fu, S.G. Mo, D.H. Ou, X.L. Fang, N.F. Zheng, A two-dimensional porous carbon-modiﬁed separator for high-energy-density Li-S batteries, Joule 2 (2017) 323–336, https://doi.org/10.1016/j.joule.2017.12.003. Y.B. He, Z.C. Chang, S.C. Wu, Y. Qiao, S. Bai, K.Z. Jiang, P. He, H.S. Zhou, Simultaneously inhibiting lithium dendrites growth and polysulﬁdes shuttle by a ﬂexible MOF-based membrane in Li-S batteries, Adv. Energy Mater. 8 (2018)