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High Performance Room Temperature Sodium-Sulfur Battery by Eutectic Acceleration in Tellurium-doped Sulfurized Polyacrylonitrile Shuping Li, Ziqi Zeng, Jiaqiang Yang, Zhilong Han, Wei Hu, Lihui Wang, Jingqi Ma, Bin Shan, and Jia Xie ACS Appl. Energy Mater., Just Accepted Manuscript • DOI: 10.1021/acsaem.9b00343 • Publication Date (Web): 01 Apr 2019 Downloaded from http://pubs.acs.org on April 2, 2019

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ACS Applied Energy Materials

High Performance Room Temperature Sodium-Sulfur Battery by Eutectic Acceleration in Tellurium-doped Sulfurized Polyacrylonitrile Shuping Li1, 2, Ziqi Zeng1, Jiaqiang Yang1, Zhilong Han1, Wei Hu1, Lihui Wang1, 2, Jingqi Ma1, 2, Bin Shan2, Jia Xie1, * 1 State

Key Laboratory of Advanced Electromagnetic Engineering and Technology

School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074, P. R. China 2

School of Materials Science and Engineering Huazhong University of Science and

Technology Wuhan 430074, P. R. China *Correspondence: [email protected]

Abstract Room-temperature sodium-sulfur batteries suffer from slow reaction kinetics and polysulfide dissolution, resulting in poor performance. Sulfurized polyacrylonitrile is a unique sulfur cathode which is suggested to involve only S3-4 and shows high specific capacity. Herein, the designed Te0.04S0.96@pPAN with 4 mol% Te used as eutectic accelerator exhibits significantly enhanced reaction kinetics and excellent sulfur utilization, leading to a high performance RT Na-S battery. Te0.04S0.96@pPAN delivers capacities of 1236 and 629 mA h g-1, 1111 and 601 mA h g-1 at 0.1 and 6 A g-1 in carbonate and ether electrolytes, respectively. Furthermore, UV-vis spectra and shuttle current test reveal diminished sodium polysulfides in ether electrolyte, attributed to the 1

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fast kinetics enabled by Te-doping. More significantly, the spectral technique and electrochemical analysis demonstrate a two-step reaction pathway in which Na2S3 and Na2S are the main intermediate and final discharge-product, respectively. This method provides a promising approach towards applicable RT Na-S batteries.

Keywords: Sulfurized polyacrylonitrile, Eutectic accelerator, Reaction kinetics, Reaction pathway, Room temperature sodium-sulfur

Introduction A constantly increasing demand for energy and environmental protection is igniting global interests in electrified transportation and smart grids with high percentage renewable energy sources such as solar and wind. 1 Successful employment of these technologies will require electrical energy storage devices, such as lithium or sodium batteries.

2-9

Due to its abundant resources, low cost as well as high energy density

(1247 W h kg-1), 10 sodium-sulfur batteries have received extensive attention for their potential in large-scale energy storage systems. 11-14 At present, the commercial sodiumsulfur battery must operate at above 300 degrees with molten sulfur and sodium, which usually shows poor cycle life and raises safety concerns and maintenance issues13. Meanwhile the final product is Na2Sn (n ≥ 3) rather than Na2S, resulting in shadow charge/discharge depth and limited energy density. 15 Thus, it is imperative to develop room temperature (RT) sodium-sulfur batteries with high energy density and high reactivity. 11, 12, 16, 17 2


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Besides similar challenges faced in lithium-sulfur batteries, RT sodium-sulfur batteries suffer from limited active material utilization due to severely low reactivity of sulfur cathode and poor kinetics of sodium.

4, 16, 18

Strategies used in lithium-sulfur

batteries to improve reactivity and reduce the dissolution of polysulfide can also be applied to RT sodium-sulfur batteries. 11, 14, 19-26 Although certain improvements have been achieved, the performances of RT Na-S batteries are still limited by the poor electrochemical activity 11, 27 due to the sluggish transport of large sodium ion 4, slow reaction kinetics12, 28 and parasitic reaction of sodium polysulfides to sodium sulfide.22 In general, S8 cathode always reacts in a parasitic fashion in which multiple steps are required to convert S8 to Na2S and various parasitic soluble polysulfides co-exist,14, 16 so that it is extremely difficult to avoid polysulfide dissolution.

11, 17

Hence, using

short chain S2-4 cathode can reduce reaction pathway and generate only soluble Na2S34

or insoluble Na2S2 intermediates, no longer in a parasitic nature, thus accelerating

redox conversion could afford fast reaction kinetics and diminish polysulfide dissolution. 29, 30 Two types of short chain sulfur S2-4 cathodes have been demonstrated in Na-S batteries: sulfur constrained in microporous carbon (S2/MicroC) 28 or chemical bonded within polymer (sulfurized polyacrylonitrile, S@pPAN).

30, 31, 32

Guo has

reported the S2/MicroC shows a two-step reaction pathway from S2 to Na2S2 and then to Na2S. 29 However, due to the “quasi-solid-state” mechanism, the intrinsic reactivity is limited. On the other hand, S@pPAN, firstly reported by Wang and used for sodiumsulfur battery in 2007, 30 shows a high specific capacity, good long cycle life and limited but better rate performance than S2 type cathodes, usually in carbonate electrolyte. Choi 3



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has designed one-dimensional S@pPAN fibers with improved electron conductivity and rate performance. 33 Lou has shown that Se-doped S@pPAN (SeS2 sulfurized with PAN) with improved rate performance delivers 302 mA h g-1 at 5 A g-1, due to high Se molar content (> 33 mol %).34 However, the fact that S@pPAN-Na/Li batteries usually work well in carbonate but not in ether electrolytes still suggests a low reactivity problem. Because in carbonate, it is probably due to the formation of protective layer by reaction with carbonate electrolyte so that no detectable generation and dissolution of polysulfides.35, 36, 37 In ether electrolyte, due to the high solubility of polysulfides and low reactivity, the dissolution of polysulfides are faster than redox conversion, resulting in poor performance. 38 However, sodium metal anode is usually more stable in ether electrolyte than in carbonate electrolyte. 39 The situation will be more severe for sodium than lithium since the redox conversion is slower due to the poor reactivity of sodium. 28

Thus, accelerating the redox conversion of S@pPAN cathodes should not only be the

key to improve reactivity and rate performance, but also mitigate polysulfide dissolution and afford compatibility with both ether and carbonate electrolytes. The accelerators have also been promoted by Huang’s group for lithium sulfur batteries.40, 41

Traditional accelerators (including sulfides,

42

oxides

43

and nitrides

44)

usually

involve nano-size materials and rather complicated process for uniform distribution. 45 Furthermore, a certain amount of loading is required for significant acceleration, in which the added weight will lower the energy density. Recent work has demonstrated that small amount of Te-doping can act as effective rate accelerator in sulfur for high rate lithium sulfur batteries. 46, 47, 48 4


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We name the effect of Te in S as eutectic accelerator due to formation of Te-S eutectic system, which facilitates molecular level distribution of Te and S. Meanwhile Te can contribute capacity and enhance reactivity due to its own redox reaction and presumably high electronic conductivity. Herein, we design Te-doped sulfurized polyacrylonitrile for Na-S battery to achieve faster reactivity and prevent polysulfide dissolution. It is shown with 4 mol% Te-doping, Na-Te0.04S0.96@pPAN cell delivers high capacity, excellent rate and cycling performance in both ether and carbonate electrolytes. Te0.04S0.96@pPAN cathode delivers capacities of 1236 and 629 mA h g-1, 1111 and 601 mA h g-1 at 0.1 and 6 A g-1 in carbonate and ether electrolytes, respectively. Te0.04S0.96@pPAN still delivers 970 mA h g-1 over 600 cycles at 0.5 A g1,

with a degradation rate 0.015%. Furthermore, spectral technique and electrochemical

analysis have demonstrated Na2S3 and Na2S are the main intermediate and final discharge product. The strategy of using Te as eutectic accelerator in sulfurized polyacrylonitrile should be fruitful towards high performance RT Na-S batteries. Results and Discussion Synthesis and Characterization of Te0.04S0.96@pPAN and S@pPAN Composites The Te0.04S0.96@pPAN is synthesized by sulfurizing PAN with Te0.0025S0.9975 prepared according to literature procedure. 31, 49, 50 In Figure 1a, the Te0.04S0.96@pPAN material is an irregular spherical shape with a diameter of about 500 nm. There are mainly C, N, S and Te elements and the corresponding elements mapping are uniform (Figure S1 and Figure 1b). The XRD data of Te0.0025S0.9975 is the analogous to that of S, without the characteristic peaks of Te (Figure 1c). Furthermore, the Raman spectra of Te0.0025S0.9975 5



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is same as S (Figure 1d). After sulfurized with PAN, S@pPAN and Te0.04S0.96@pPAN present identical XRD data. In addition, Te0.04S0.96@pPAN shows similar Raman spectra to S@pPAN and there are characteristic peaks of S-S bond (472 cm-1 and 926 cm-1) and C-S bond (306 cm-1 and 366 cm-1) (Figure 1 d).

31

The FTIR spectra of

S@pPAN and Te0.04S0.96@pPAN are similar and there are also C-S bond (931cm-1) and S-S bond (513 cm-1), which is consistent with Raman spectra (Figure 1e). 31 The S highresolution XPS spectra of Te0.04S0.96@pPAN shows C-S, S-S and S-Te peaks (Figure 1f). The C-S and S-S are comparable as those in S@pPAN (Figure S2). 49 Furthermore, the C and N 1s XPS spectrum of Te0.04S0.96@pPAN and S@pPAN are very similar, which are consistent with Raman and FTIR spectrum analysis (Figure S3). Thus, S@pPAN and Te0.04S0.96@pPAN have similar chemical structure, although the exact structure of S@pPAN is still unclear. The active material content of Te0.04S0.96@pPAN (47.77%) is higher than that of S@pPAN (42.06%) by weight but very close in molecular ratio. Based on the composites, the theoretical specific capacity of Te0.04S0.96@pPAN (714 mA h g-1) is slightly higher than that of S@pPAN (704 mA h g-1) (Table S1).

6


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Figure 1. The morphologies and spectrum characterization of Te0.04S0.96@pPAN and S@pPAN. (a and b) The TEM picture of Te0.04S0.96@pPAN and the corresponding C, N, S and Te elements mapping of Te0.04S0.96@pPAN. (c and d) The XRD and Raman spectrum of S, Te, Te0.0025S0.9975, S@pPAN and Te0.04S0.96@pPAN. (e) The Fourier transform infrared (FTIR) spectrum of S@pPAN and Te0.04S0.96@pPAN. (f) The highresolution S 2p XPS spectra of Te0.04S0.96@pPAN.

7



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Figure 2. The electrochemical performance of Te0.04S0.96@pPAN and S@pPAN in carbonate and ether electrolytes. (a and b) The comparison of rate performance of S@pPAN and Te0.04S0.96@pPAN, and voltage-capacity curves of Te0.04S0.96@pPAN at various current densities in carbonate electrolyte. (c and d) The comparison of rate performance of S@pPAN and Te0.04S0.96@pPAN, and voltage-capacity curves of Te0.04S0.96@pPAN at various current densities in ether electrolyte. (e) The long cycle performance of Te0.04S0.96@pPAN-Na cells at 0.5 A g-1 in carbonate electrolyte. (f) The long cycle performance of S@pPAN-Na and Te0.04S0.96@pPAN-Na cells at 1 A g-1 in ether electrolyte. Electrochemical Performance of Te0.04S0.96@pPAN and S@pPAN for RT Sodium 8


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Sulfur Batteries in Carbonate and Ether Electrolytes The electrochemical performance of Te0.04S0.96@pPAN is firstly studied for sodium-sulfur battery in carbonate electrolyte. The voltage range (0.7-2.8 V) for sodium sulfur batteries is determined based on the cyclic voltammetry (CV) curve, charge/discharge curves and cycle performance analysis (Figure S4-5).

51,52

The rate performance of

Te0.04S0.96@pPAN and S@pPAN are shown in Figure 2a and 2b. In Figure 2a, Te0.04S0.96@pPAN composite delivers 1816, 1132, 1080, 1035, 981, 893, 785 and 629 mA h g-1, at 0.1, 0.5, 1, 2, 3, 4, 5 and 6 A g-1. In contrast, S@pPAN cathode delivers only 234 mA h g-1 at 6 A g-1. The carbonized polyacrylonitrile is also used as control experiment and contributes very little capacity for sodium battery (Figure S6). The specific capacities of Te0.04S0.96@pPAN and S@pPAN are mainly supplied by sulfur and tellurium redox reaction with sodium. The active material utilization of Te0.04S0.96@pPAN are much higher than that of S@pPAN at various current densities, especially at high current densities (Figure S7). At high current density of 6 A g-1, the active material utilization is 41.8%. Te0.04S0.96@pPAN composite delivers an initial discharge capacity of 1816 mA h g-1 and a high reversible capacity 1236 mA h g-1, which suggests a completed discharge to Na2S/ Na2Te. Meanwhile, Te0.04S0.96@pPAN delivers a capacity of 1067 mA h g-1 after two cycles activation and stable capacity of 970 mA h g-1 over 600 cycles at 0.5 A g-1, showing a degradation rate 0.015% (Figure 2e). Moreover, based on the Te0.04S0.96@pPAN composite, the specific capacity is 503 mA h g-1 and a stable capacity of 463 mA h g-1 is maintained over 600 cycles. However, S@pPAN only delivers 736 mA h g-1 over 300 cycles, with a degradation rate 0.09% 9



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(Figure S8). The capacity decay rate of S@pPAN is six times larger than that of Te0.04S0.96@pPAN. Similar electrochemical studies are also conducted in ether electrolyte. The ether electrolyte is composed of 1M NaClO4 with 10% FEC in DOL/DME (v: v=1:1), and FEC additive has been shown to be able to stabilize sodium metal anode and help prevent polysulfide dissolution at the same time. 53 Te0.04S0.96@pPAN delivers 1682, 1031, 992, 886, 810, 741, 673 and 601 mA h g-1, at 0.1, 0.5, 1, 2, 3, 4, 5 and 6 A g-1 (Figure 2c-d). S@pPAN shows much lower capacities at the same current densities. The active material utilization ratio of Te0.04S0.96@pPAN are higher than that of S@pPAN

at

various

current

densities

in

ether

electrolyte

(Figure

S9).

Te0.04S0.96@pPAN delivers 894 mA h g-1 at 1 A g-1 with a degradation rate 0.031% over 500 cycles (Figure 2f). In contrast, S@pPAN delivers 470 mA h g-1 capacity with a degradation rate 0.064% over 500 cycles. The collective results clearly show that the electrochemical performance of Te0.04S0.96@pPAN is superior to S@pPAN.

10


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Figure 3. The reaction kinetics study of Te0.04S0.96@pPAN and S@pPAN cathodes. (a) The electronic conductivity of Te0.04S0.96@pPAN and S@pPAN. (b) The comparison of Na+ diffusion coefficient of Te0.04S0.96@pPAN and S@pPAN. (c and d) The reaction resistance at various depth of discharge and at various state of charge in carbonate and ether electrolytes. (e) The UV-visible spectrum of Te0.04S0.96@pPAN and S@pPAN cathodes in ether electrolyte. (f) The shuttle current test of Te0.04S0.96@pPAN and S@pPAN cathodes in ether electrolyte. The Study of Reaction Kinetics of Te0.04S0.96@pPAN and S@pPAN Composite Cathode The rate performance of Te0.04S0.96@pPAN is far superior to traditional S@pPAN materials. In order to gain further insight of the fast kinetics of Te0.04S0.96@pPAN, the electronic conductivity, Na+ diffusion coefficient and reaction resistance are investigated by electrochemical technologies.54 The electronic conductivity of Te0.04S0.96@pPAN is shown to be 1.65 times higher than S@pPAN 11



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measured by DC polarization method (Figure 3a, and Table S2). The Na ion diffusion coefficient of Te0.04S0.96@pPAN are two or three times higher than S@pPAN in both reduction and oxidation processes, which suggests that Te-doping facilitates the Na+ charge transfer (Figure 3b, Figure S10 and Figure S11). Furthermore, as calculated by density functional theory, the diffusion energy barrier of Na in Te0.04S0.96@pPAN (0.42 eV) is lower than in S@pPAN (1.03 eV) (Figure S12). As shown in GITT curves, Te0.04S0.96@pPAN shows higher specific capacity and smaller overpotential (Figure S13). The reaction resistances of Te0.04S0.96@pPAN are smaller than that of S@pPAN at various state in both carbonate and ether electrolytes (Figure 3c-d). The morphologies sodium anodes for Te0.04S0.96@pPAN in ether and carbonate electrolytes are present in Figure S14. The surface of sodium anodes are smooth without obvious dendrites, so the Te0.04S0.96@pPAN cathodes show good long cycle performance in both ether and carbonate electrolytes. For UV-visible spectra measurement, the cycled coin cells are disassembled and the cathodes are immersed in TEGDME solvent, which afford the solution for studying. In Figure 3e, the obvious peak at 260 nm is confirmed to S2-/S22-, and the shoulder peak at 315 nm is respected to S32-.

12

The characteristic peak of S32- is obvious for S@pPAN composite and is

hardly detectable for Te0.04S0.96@pPAN, indicating less or no soluble polysulfides for Te0.04S0.96@pPAN cathode. This result suggests that Te can effectively accelerate the redox conversion of soluble polysulfide into insoluble products. Due to the shuttle effect, the shuttle current of S@pPAN is fluctuated with time (Figure 3f).22 Since there is merely no soluble polysulfides for Te0.04S0.96@pPAN, the shuttle current decay 12


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rapidly with time. Because Te accelerates the conversion between sodium polysulfide and sodium sulfide without the shuttling effect, the EIS of Te0.04S0.96@pPAN is stable with increased cycling, especially the SEI resistance (Figure S15 and Scheme S1). Hence, Te-doping can promote Na+ diffusion and reduce reaction resistances, resulting in fast kinetics from soluble polysulfide to insoluble products and ultimately leading to excellent rate performance and diminished polysulfide dissolution. Two-Step Reaction Pathway of Te0.04S0.96@pPAN and S@pPAN Composite The electrochemical and spectral techniques are employed to explore the reaction pathway of Te0.04S0.96@pPAN. It seems that there are a two-step processes during charging and discharging (Figure 4a), in which there are two reduction peaks at 1.90 and 1.25 V (Peak A and Peak B), and two oxidation peaks at 1.88 and 2.31 V (Peak C and Peak D). The capacity ratio of Peak A and Peak B is 1:2 (based on integration of CV curve), which is consistent with voltage capacity curve in Figure 4b. Based on the relation of transferred electrons number and capacity, the intermediate of Peak A is Na2S3 (2/3 electron transfer), and the completely discharge product of Peak B is Na2S (4/3 electron transfer). 22 The charge process follows the same rule, in which the charge intermediate of Peak C is Na2S3, and the final charge product of Peak D should be equivalent to elemental S3.

22, 29

The generation of S32- has been observed by UV-vis

spectra (Figure 3e). The same conclusion is obtained for S@pPAN (Figure S16). In ether electrolyte, these results are consistent as in carbonate electrolyte (Figure S17).

13



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Figure 4. The investigation of the reaction pathway of Te0.04S0.96@pPAN cathode for sodium sulfur battery. (a and b) The analysis of the cyclic voltammetry (CV) curve and voltage capacity curve. (c) The S high-resolution XPS spectrum of Te0.04S0.96@pPAN at fully discharged and charged states. (d) The suggested reaction pathway of Te0.04S0.96@pPAN composite cathode. (e and f) The initial discharge/charge voltagecapacity profile and corresponding semi in-suit Raman spectrum. The initial discharge/charge processes are studied by XPS and Raman spectrum to confirm this result. The S high-resolution XPS of S@pPAN and Te0.04S0.96@pPAN at fully discharged and charged states are presented in Figure S18 and Figure 4c. At fully discharged state, the new peak at 159.84 and 161 eV is confirmed to S2- 2p 3/2 and 2p 1/2, therefore the final discharged product is Na2S 29 and high-resolution XPS spectra 14


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of Te 3d peak is shift as Na2Te formed (Figure S19). 55 At fully charged state, there are S-S and C-S bonds for S@pPAN cathode (Figure S18), and S-S, C-S and S-Te (162.1 and 163.1 eV) bonds present for Te0.04S0.96@pPAN cathode. 46, 50 Hence, the number of transferred electrons in sodium-sulfur batteries is 2. It is reasonable to propose that Na2S3 is the main intermediate and the suggested pathway is presented in Figure 4d, indicating a two-step reaction. The suggested reaction is further supported by semi in situ Raman spectra. The characteristic Raman peak of S-S (472 cm-1) completely disappears at 0.7 V as the fully discharged product is Na2S without S-S peak, and reappears at 2.8 V at the fully charged state since S-S peak exists (Figure 4e-f). 31 At discharging to 1.5 V and charging to 2.0 V, there are obvious S-S peak at 472 cm-1, so that the intermediate is suggested to be Na2S3, which is consistent with the CV analysis result. In short, though under the dissolution-deposition mechanism, using Te as eutectic accelerator in S@pPAN-Na successfully accelerates the transformation of soluble Na2S3, leading to excellent rate and long cycle performance in both carbonate and ether electrolytes.

Figure 5. The comparison of rate performance of various cathodes for sodium-sulfur batteries. (a) Carbonate electrolyte. (b) Ether electrolyte. The Comparison of Te0.04S0.96@pPAN and S@pPAN Composite Cathodes 15



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with Oher Cathode Materials Figure 5 lists the comparative results of the designed Te0.04S0.96@pPAN with other reported sulfur cathodes in Na-S batteries. It is clear that the rate performance of Te0.04S0.96@pPAN is among the best in both carbonate and ether electrolytes (Figure 5a and Figure 5b). 20, 23, 29, 32, 34, 56, 57 The cycle performance of various cathode materials are listed in Table S3, the Te0.04S0.96@pPAN composite cathode delivers the lowest capacity decay of 0.015%. Notably, in ether electrolyte, the cycle performance is significantly improved (Table S4). 14, 18, 21, 58, 59 Conclusion In

conclusion,

we

have

successfully

designed

Te-doped

sulfurized

polyacrylonitrile Te0.04S0.96@pPAN, which delivers excellent electrochemical performance in both carbonate and ether electrolytes. Te serves as eutectic accelerator which enhances the electron conductivity and promotes Na sodium diffusion, resulting in faster kinetics and lower reaction resistance. As proved by UV-vis spectra and shuttle current test, Te accelerates the conversion between sodium polysulfide and sodium sulfide, which diminishes polysulfide dissolution and relieves the shuttle effect. More importantly, it is shown to be a two-step reaction pathway reaction mechanism with Na2S3 as intermediate. It is the first time reported sulfurized polyacrylonitrile shows excellent compatibility in both carbonate and ether electrolytes, and presents a promising solution towards RT Na-S batteries.

Supporting Information The supplemental Information is available free of charge on the ACS Publications website. Experimental methods, EDS of Te0.04S0.96@pPAN, XPS of S and Te high 16


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resolution, cycle performance, DFT calculation of sodium ion diffusion barrier, EIS of Te0.04S0.96@pPAN and S@pPAN, the calculation of sodium ion diffusion coefficient, CV curves of Te0.04S0.96@pPAN and S@pPAN and corresponding analysis, GITT curves, and comparisons of electrochemical performance of this work with previous excellent works. Author Information Shuping Li https://orcid.org/0000-0002-3843-0917 Corresponding author E-mail: [email protected]

Tel.: +86 027 87540302

Notes The authors declare no competing interest. Acknowledgements This work was supported by the National Basic Research Program of China (973 Program, 2015CB258400), and the Program for HUST Interdisciplinary Innovation Team (2015ZDTD021). The authors gratefully thanks the Analytical and Testing Center of HUST for a variety of equipments. References (1) Chu, S., Cui, Y. and Liu, N. The path towards sustainable energy. Nat. Mater. 2016, 16, 16-22. (2) Dunn, B., Kamath, H., Tarascon, J. M.. Electronical energy storege for the grid battery is choices. Science 2011, 334, 928-935. (3) Armand, M., Tarascon, J.-M. Issues and challenges facing rechargeable lithium batteries. Mater. Sustainable Energy 2001, 414, 359-369. (4) Adelhelm, P., Hartmann, P., Bender, C.L., Busche, M., Eufinger, C., and Janek, J. From lithium to sodium: cell chemistry of room temperature sodium-air and sodium-sulfur batteries. Beilstein J. Nanotech. 2015, 6, 1016-1055. (5) Lu, Y., Zhang, Q., Li, L., Niu, Z., and Chen, J. Design strategies toward enhancing the performance of organic electrode materials in metal-ion batteries. Chem 2018, 17



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4, 2786-2813. (6) Liu, Y., Zhao, X., Fang, C., Ye, Z., He, Y.-B., Lei, D., Yang, J., Zhang, Y., Li, Y., Liu, Q., et al. Activating aromatic rings as Na-ion storage sites to achieve high capacity. Chem 2018, 4, 2463-2478. (7) Zhao, Y., Zheng, K., and Sun, X.. Addressing interfacial issues in liquid-based and solid-state batteries by atomic and molecular layer deposition. Joule 2018, 2, 25832604. (8) Wang, H., Yu, D., Kuang, C., Cheng, L., Li, W., Feng, X., Zhang, Z., Zhang, X., and Zhang, Y. Alkali metal anodes for rechargeable batteries. Chem 2018, 5, 1-26. (9) Wang, X., Shang, Z., Yang, A., Zhang, Q., Cheng, F., Jia, D., and Chen, J. Combining quinone cathode and ionic liquid electrolyte for organic sodium-ion batteries. Chem 2018, 5, 1-12. (10) Seh, Z.W., Sun, J., Sun, Y., and Cui, Y. A Highly reversible room-temperature sodium metal anode. ACS Cent. Sci. 2015, 1, 449-455. (11) Wang, Y.-X., Zhang, B., Lai, W., Xu, Y., Chou, S.-L., Liu, H.-K., and Dou, S.-X. Room-temperature sodium-sulfur batteries: a comprehensive review on research progress and cell chemistry. Adv. Energy Mater. 2017, 7, 1602829. (12) Wei, S., Xu, S., Agrawral, A., Choudhury, S., Lu, Y., Tu, Z., Ma, L. and Archer, L.A. A stable room-temperature sodium-sulfur battery. Nat. Commun. 2016, 7 11722. (13) Hueso, K. Palomares, B.V., Armand, M., and Rojo, T. Challenges and perspectives on high and intermediatetemperature sodium batteries. Nano Res. 2017, 10, 40824114. (14) Qiang, Z., Chen, Y.-M., Xia, Y., Liang, W., Zhu, Y., and Vogt, B.D. Ultra-long cycle life, low-cost room temperature sodium-sulfur batteries enabled by highly doped (N,S) nanoporous carbons. Nano Energy 2017, 32, 59-66. (15) Lu, X., Kirby, B.W., Xu, W., Li, G., Kim, J.Y., Lemmon, J.P., Sprenkle, V.L., and Yang, Z. Advanced intermediate-temperature Na–S battery. Energy Environ. Sci. 2013, 6, 299-306. (16) Manthiram, A., and Yu, X. Ambient temperature sodium-sulfur batteries. Small 2015, 11, 2108-2114. (17) Xu, X., Zhou, D., Qin, X., Lin, K., Kang, F., Li, B., Shanmukaraj, D., Rojo, T., Armand, M., and Wang, G. A room-temperature sodium–sulfur battery with high capacity and stable cycling performance. Nat. Commun. 2018, 9, 3870. (18) Yu, X., and Manthiram, A. Ambient-temperature sodium-sulfur batteries with a sodiated nafion membrane and a carbon nanofiber-activated carbon composite electrode. Adv. Energy Mater. 2015, 5, 1500350. (19) Zhang, B.W., Sheng, T., Liu, Y.D., Wang, Y.X., Zhang, L., Lai, W.H., Wang, L., Yang, J., Gu, Q.F., Chou, S.L., et al. Atomic cobalt as an efficient electrocatalyst in sulfur cathodes for superior room-temperature sodium-sulfur batteries. Nat. Commun. 2018, 9, 4082. (20) Zeng, L., Yao, Y., Shi, J., Jiang, Y., Li, W., Gu, L., and Yu, Y. A flexible S1−xSex@porous carbon nanofibers (x≤0.1) thin film with high performance for Li-S batteries and room-temperature Na-S batteries. Energy Storage Mater. 2016, 18


Page 19 of 22 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


5, 50-57. (21) Chen, Y.-M., Liang, W., Li, S., Zou, F., Bhaway, S.M., Qiang, Z., Gao, M., Vogt, B.D., and Zhu, Y. A nitrogen doped carbonized metal–organic framework for high stability room temperature sodium–sulfur batteries. J. Mater. Chem. A 2016, 4, 12471-12478. (22) Yu, X., and Manthiram, A. Capacity enhancement and discharge mechanisms of room-temperature sodium-sulfur batteries. ChemElectroChem 2014, 1, 1275-1280. (23) Zheng, S., Han, P., Han, Z., Li, P., Zhang, H., and Yang, J. Nano-copper-assisted immobilization of sulfur in high-surface-area mesoporous carbon cathodes for room temperature Na-S batteries. Adv. Energy Mater. 2014, 4, 1400226. (24) Peng, H.-J., and Zhang, Q. Designing host materials for sulfur cathodes: from physical confinement to surface chemistry. Angew. Chem. Int. Ed. 2015, 54, 11018-11020. (25) Zhao, R., Liang, Z., Zou, R., and Xu, Q. Metal-organic frameworks for batteries. Joule 2018, 2, 2235-2259. (26) Li, S., Chen, X., Hu, F., Zeng, R., Huang, Y.H., Yuan, L.X., Xie, J. Cobaltembedded carbon nanofiber as electrocatalyst for polysulfide redox reaction in lithium sulfur batteries Electrochim. Acta 2019, 304, 11-19. (27) Zhang, L., Zhang, B., Dou, Y., Wang, Y., Al-Mamun, M., Hu, X., and Liu, H. Self-assembling hollow carbon nanobeads into double-shell microspheres as a hierarchical sulfur host for sustainable room-temperature sodium-sulfur batteries. ACS Appl. Mater. Interfaces 2018, 10, 20422-20428. (28) Hong, X., Mei, J., Wen, L., Tong, Y., Vasileff, A.J., Wang, L., Liang, J., Sun, Z., and Dou, S.X. Nonlithium metal-sulfur batteries: steps toward a leap. Adv. Mater. 2018, 1802822. (29) Xin, S., Yin, Y.X., Guo, Y.G., and Wan, L.J. A high-energy room-temperature sodium-sulfur battery. Adv. Mater. 2014, 26, 1261-1265. (30) Wang, J., Yang, J., Nuli, Y., and Holze, R. Room temperature Na/S batteries with sulfur composite cathode materials. Electrochem. Commun. 2007, 9, 31-34. (31) Wei, S., Ma, L., Hendrickson, K.E., Tu, Z., and Archer, L.A. Metal-sulfur battery cathodes based on PAN-sulfur composites. J. Am. Chem. Soc. 2015, 137, 1214312152. (32) Zhang, Y., Sun, Y., Peng, L., Yang, J., Jia, H., Zhang, R., Shan, B., Xie, J., Se as eutectic accelerator in sulfuried polyacrylonitrile for high performance all-solid state lithium-sulfur battery Energy Storage Mater. 2018, https://doi.org/10.1016/j. ensm.2018.12.010. (33)Hwang, T.H., Jung, D.S., Kim, J.S. and Choi, J.W. One-Dimensional carbon−sulfur composite fibers for Na−S rechargeable batteries operating at room temperature. Nano Lett. 2013, 13, 4532-4538. (34) Li, Z., Zhang, J., Lu, Y., Lou, X.W. (David) A pyrolyzed polyacrylonitrile/selenium disulfide composite cathode with remarkable lithium and sodium storage performances. Sci. Adv. 2018, 4, 1687. (35) Chen, X., Peng, L., Wang, L., Yang, J., Hao, Z., Xiang, J., Yuan, K., Huang, Y.H., Shan, B., Xie, J. Ether-compatible sulfurized polyacrylonitrile cathode with 19



Page 20 of 22

excellent performance enabled by fast kinetics via selenium doping Nat. Commun. 2019, https://doi.org/10.1038/s41467-019-08818. (36) He, F., Wu, X., Qian, J., Cao, Y., Yang, H.X., Ai, X.P., Xia, D.G., Building a cycle-stable sulphur cathode by tailoring its redox reaction into a solid-phase conversion mechanism J. Mater. Chem. A, 2018, 6, 23396-23407. (37) Yim, T., Park, M., Yu, J., Kim, K.J., Im, K.Y., Kim, J.H., Jeong, G., Jo, Y., Woo, S.G., Kang, K.S., Lee, I., Kim, Y.J. Effect of chemical reactivity of polysulfide toward carbonate-bassed electrolyte on the electrochemical performance of Li-S batteries Electrochim. Acta 2013, 107, 454-460. (38) Wang, L., He, X., Li, J., Chen, M., Gao, J., and Jiang, C. Charge/discharge characteristics of sulfurized polyacrylonitrile composite with different sulfur content in carbonate based electrolyte for lithium batteries. Electrochim. Acta 2012, 72, 114-119. (39) Shi, Q., Zhong, Y., Wu M., Wang, H., Wang, H.L. High-capacity rechargeable batteries based on deeply cyclable lithium metal anodes PNAS 2018, 115, 56765680. (40) Zhao, M., Peng., H.J., Zhang, Z.W., Li, B.Q., Chen, X., Xie, J., Chen, X., Wei, J.Y., Zhang, Q., Huang, J.Q. Angew. Chem. Int. Ed. 2019, 58, 3779-3783. (41) Zhang, Z., Peng, H.J., Zhao, M., Huang, J.Q. Heterogeneous/homogeneous mediators for high-energy-density lithium-sulfur batteries: progress and prospects Adv. Funct. Mater. 2018, 28, 1707536. (42) Lin, H., Yang, L., Jiang, X., Li, G., Zhang, T., Yao, Q., Zheng, G.W., and Lee, J.Y. Electrocatalysis of polysulfide conversion by sulfur-deficient MoS2 nanoflakes for lithium–sulfur batteries. Energy Environ. Sci. 2017, 10, 1047-1058. (43) Pang, Q., Kundu, D., Cuisinier, M., and Nazar, L.F. Surface-enhanced redox chemistry of polysulphides on a metallic and polar host for lithium-sulphur batteries. Nat. Commun. 2014, 5, 4759. (44) Zhou, J., Liu, X., Zhu, L., Zhou, J., Guan, Y., Chen, L., Niu, S., Cai, J., Sun, D., Zhu, Y., et al. Deciphering the modulation essence of p bands in Co-based compounds on Li-S chemistry. Joule 2018, 2, 2681-2693. (45) Pang, Q., Kwok, C.Y., Kundu, D., Liang, X., and Nazar, L.F. Lightweight metallic MgB2 mediates polysulfide redox and promises high-energy-density LithiumSulfur Batteries. Joule 2019, 3, 136-148. (46) Xu, K., Liu, X., Liang, J., Cai, J., Zhang, K., Lu, Y., Wu, X., Zhu, M., Liu, Y., Zhu, Y., et al. Manipulating the redox kinetics of Li–S chemistry by tellurium doping for improved Li–S batteries. ACS Energy Lett. 2018, 3, 420-427. (47) Sun, F., Zhang, B., Tang, H., Yue, Z., Li, X., Yin, C., and Zhou, L. Heteroatomic TexS1-x molecule/C nanocomposites as stable cathode materials in carbonate-based electrolytes for lithium–chalcogen batteries. J. Mater. Chem. A 2018, 6, 1010410110. (48) Li, S., Han, Z., Hu, W., Peng, L., Yang, J., Wang, L., Zhang, Y., Shan, B., Xie, J. Manipulating kinetics of sulfurized polyacrylonitrile with tellurium as eutectic accelerator to prevent polysulfide dissolution in lithium-sulfur battery under dissolution-deposition mechanism Nano Energy 2019, 60, 153-161. 20


Page 21 of 22 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


(49) Wang, J.L., Yang, J., Wan, C., Du, K., Xie, J.Y., Xu, N.X. Sulfur composite cathode material for rechargeable lithium batteries. Adv. Funct. Mater. 2013, 13, 487-492. (50) Jin, Z.-Q., Liu, Y.-G., Wang, W.-K., Wang, A.-B., Hu, B.-W., Shen, M., Gao, T., Zhao, P.-C., and Yang, Y.-S. A new insight into the lithium storage mechanism of sulfurized polyacrylonitrile with no soluble intermediates. Energy Storage Mater. 2018, 14, 272-278. (51) Fan, L., Ma, R., Yang, Y., Chen, S., Lu, B., Covalent sulfur for advanced room temperature sodium-sulfur batteries Nano Energy 2016, 28, 304-310. (52) Wu, T., Jing, M., Yang, L., Zou, G., Hou, H., Zhang, Y., Zhang, Y., Cao, X., Ji, X. Controllable chain-length for covalent sulfur-carbon materials enabling stable and high capacity sodium storage Adv. Energy Mater. 2018, 1803478. (53) Weng, W., Pol, V.G., and Amine, K. Ultrasound assisted design of sulfur/carbon cathodes with partially fluorinated ether electrolytes for highly efficient Li/S batteries. Adv. Mater. 2013, 25 1608-1615. (54) Ghazi, Z.A., He, X., Khattak, A.M., Khan, N.A., Liang, B., Iqbal, A., Wang, J., Sin, H., Li, L., and Tang, Z. MoS2/celgard separator as efficient polysulfide barrier for long-life lithium-sulfur batteries. Adv. Mater. 2017, 29, 1606817. (55) Li., J., Yuan,Y.F., Jin, H., Lu, H.H., Li, A., Yin, D., Wang, J.C., Lu, J., and Wang, S. One-step nonlinear electrochemical synthesis of TexSy@PANI nanorod materials for Li-TexSy battery. Energy Storage Mater. 2018, 16, 31-36. (56) Yu, Y., Zeng, L., Hu, S., Jiang,Y., Yuan, B.B., and Yu, Y. Binding S0.6Se0.4 in 1D carbon nanofber with C-S bonding for high-performance flexible Li–S batteries and Na–S batteries. Small 2017, 1603513. (57) Kim, I., Kim, C.H., Choi, S.h., Ahn, J.-P., Ahn, J.-H., Kim, K.-W., Cairns, E.J., and Ahn, H.-J. A singular flexible cathode for room temperature sodium/sulfur battery. J. Power Sources 2016, 307, 31-37. (58) Ghosh, A., Shukla, S., Monisha, M., Kumar, A., Lochab, B., and Mitra, S. Sulfur copolymer: a new cathode structure for room-temperature sodium–sulfur batteries. ACS Energy Lett. 2017, 2, 2478-2485. (59) Yu, X., and Manthiram, A. Na2S-carbon nanotube fabric electrodes for roomtemperature sodium-sulfur batteries. Chem. Eur. J. 2015, 21, 4233-4237.

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