Subscriber access provided by UNIV AUTONOMA DE COAHUILA UADEC
Article
Triple-Layered Carbon-SiO2 Composite Membrane for High Energy Density and Long Cycling Li-S Batteries Wei Kou, Xiangcun Li, Yang Liu, Xiaopeng Zhang, Shaoran Yang, Xiaobin Jiang, Gaohong He, Yan Dai, Wenji Zheng, and Guihua Yu ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.9b01703 • Publication Date (Web): 16 Apr 2019 Downloaded from http://pubs.acs.org on April 16, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 27 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
ACS Nano
Triple-Layered Carbon-SiO2 Composite Membrane for High Energy Density and Long Cycling Li-S Batteries Wei Kou,a Xiangcun Li,*,a Yang Liu,a Xiaopeng Zhang,a Shaoran Yang,b Xiaobin Jiang,a Gaohong He,*,a Yan Dai, a Wenji Zheng,a Guihua Yu*,c aState
Key Laboratory of Fine Chemicals, Chemical Engineering Department, Dalian
University of Technology, Dalian, 116024, China b
Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83
Tat Chee Avenue, Hong Kong, China c
Materials Science and Engineering Program and Department of Mechanical Engineering,
The University of Texas at Austin, TX 78712, USA E-mail:
[email protected];
[email protected];
[email protected] 1 ACS Paragon Plus Environment
ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Abstract Here we report a highly scalable yet flexible triple-layer structured porous C/SiO2 membrane via a facile phase inversion method for advancing Li-Sulfur battery technology. As a multifunctional current-collector-free cathode, the conductive dense layer of the C/SiO2 membrane offers hierarchical macropores as an ideal sulfur host to alleviate the volume expansion of sulfur species and facilitate ion/electrolyte transport for fast kinetics, as well as sponge-like pores to enable high sulfur loading. The triple-layer structured membrane cathode enables the filling of most sulfur species in the macropores and additional loading of a thin sulfur slurry on the membrane surface, which facilitates ion/electrolyte transport with faster kinetics than the conventional S/C slurry-based cathode. Furthermore, density functional theory (DFT) simulations and visual adsorption measurements confirm the critical role of the doped SiO2 nanoparticles (~10 nm) in the asymmetric C membrane in suppressing the shuttle effect of polysulfides via chemisorption and electrocatalysis. The rationally designed C/SiO2 membrane cathodes demonstrate long-term cycling stability of 300 cycles at a high sulfur loading of 2.8 mg cm-2 with a sulfur content of ~75%. This scalable yet flexible selfsupporting cathode design presents a useful strategy for realizing practical applications of high-performance Li-S batteries. Keywords: C/SiO2 membrane; phase-inversion; multifunctional; Li-S batteries; energy storage
Lithium-sulfur batteries have drawn considerable attention for next-generation energy storage technologies due to their high theoretical specific capacity (1675 mA h g-1) and energy density (2567 Wh/kg) based on the redox reaction of 16 Li+S8 = 8 Li2S.1,2 Given the merits of elemental abundance, cost affordability and low toxicity, sulfur has potential for 2 ACS Paragon Plus Environment
Page 2 of 27
Page 3 of 27 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
ACS Nano
large-scale commercial applications.3,4 However, many obstacles must be overcome for Sbased cathodes in Li-S batteries. First, the poor electrical conductivity of sulfur and its reduced products (Li2S/Li2S2) lead to low utilization of active materials and irreversible electrochemical reactions. The large volume expansion (~80%) of sulfur during the chargedischarge process results in the detachment of sulfur from host materials and pulverization of cathodes.5 In addition, the well-known “shuttle effect” phenomenon for soluble polysulfides (Li2Sx, 4300℃) compared to a conventional Al cathode (64.6% and ~250℃, respectively) (Figure S 6a).
Figure 1. (a) Ternary phase diagram for asymmetry porous PAN and PAN/SiO2 membranes and their carbonization into C and C/SiO2 cathode electrodes, (b) solvent exchange between DMF and nonsolvent (deionized water) for membrane solidification and pore formation, (c, d) PAN/SiO2 membrane and its carbonization into C/SiO2 flexible electrodes, (e) cross-section SEM image of the C/SiO2 composite membrane, (f) C/SiO2 membrane with S filling in the pores and S slurry coating on the top surface, (g)
8 ACS Paragon Plus Environment
Page 8 of 27
Page 9 of 27 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
ACS Nano
thick S slurry coating on C/SiO2 membrane top surface, (h) S deposition in the pores of C/SiO2 membrane, (i, j) SEM image of S slurry coating on C/SiO2 membrane and uniform S distribution, (k-m) uniform distributions of C, Si and S in C/SiO2 membrane.
Raman spectroscopy was performed to study the C and C/SiO2 composite membrane (Figure S 6b). The two typical peaks at 1350 and 1580 cm−1 can be attributed to the D and G bands, respectively, with the D band arising from the properties of lattice defects and disorder of carbon and the G band from the graphitic crystallite structure of C-C bond. The peak intensity ratio (IG/ID) of the C/SiO2 composite membranes was calculated to be 0.82, which is higher than that of the pure C membranes (0.74), showing high graphitization degree of the C/SiO2 membranes.42 From the FTIR spectra (Figure S 6c), the peak at approximately 1100 cm-1 and shoulder peak at 1350 cm-1 were ascribed to the asymmetric stretching vibration of Si-O-Si bands, and the peaks at 810 and 565 cm-1 were attributed to the symmetric stretching modes and deformation vibration of Si-O-Si, respectively.43 The result indicated successful dispersion of SiO2 nanoparticles into the C membranes. Figure 2a shows the X-ray diffraction pattern (XRD) patterns of SiO2 nanoparticles, carbon membranes, and C/SiO2 composite membranes with an amorphous structure. The sulfur loaded in the C/SiO2 membranes was ascribed to the orthorhombic sulfur crystalline (JCPDS no. 08-0247). Importantly, X-ray photoelectron spectroscopy (XPS) was used to verify the effective chemisorption capacity between SiO2 and LiPSs. In Figure 2b, every sulfur environment split into 2p3/2 and 2p1/2 doublets due to the spin orbit coupling.41 The S 2p spectrum of the C/SiO2 cathode in the discharged state exhibits two 2p2/3 peaks at 163.6 eV (SB-SiO2) and 162.3 eV (ST-SiO2), with a positive shift of 0.50 eV and 0.70 eV compared to the 163.1 eV of bridging sulfur (SB) and 161.6 eV of terminal sulfur (ST-1), respectively,44 indicating a decrease in electron density on SB and ST-1. These phenomena demonstrate the effective interaction between SiO2 and LiPSs.45 The S 2p1/2 and S 2p2/3 peaks at 171.12 eV and 169.97 eV, respectively, correspond to the sulfate that was generated by the partial 9 ACS Paragon Plus Environment
ACS Nano 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
oxidation reaction of LiPSs with oxygen when the sample was measured in the XPS. The S 2p1/2 and S 2p2/3 peaks at 169.04 eV and 167.8 eV, respectively, are related to the highly oxidized SOx, which might result from (i) the soluble LiCF3SO3 or LiTFSI in the raw electrolyte46 or (ii) the thiosulfate and polythionate species formed by the redox reaction between the LiPSs and dangling oxygen atoms in SiO2 or carbon, which also provides a strong chemisorption ability to inhibit the leakage out of LiPSs from the cathode. Moreover, the N 1s spectrum of the C membranes in Figure 2c reveals the nitrogen environment. There are three peaks in the C/SiO2 membranes with binding energies of 402.3, 400.8, and 398.7 eV, corresponding to quaternary N, pyrrolic N and pyridinic N, respectively.47,48 The binding energies of quaternary N and pyridinic N exhibit obvious +2.7 eV (405 eV) and +1.2 eV (399.9 eV) positive shifts when the N-doped C/SiO2 membranes are sulfur host materials, indicating that the doping quaternary and pyridinic N bonded with the LiPSs via Li-N bonds.41 This dual-doped (SiO2 and N doping) carbon membrane had stronger chemisorption with the LiPSs compared with other doped carbon materials, thus effectively mitigating sulfur species shuttling. In the high-resolution C 1s spectra (Figure S 6d), the C/SiO2 membrane displays peaks at 285.5 eV (C-O and C-N) and 288.7 eV (C=O and C=N), further reflecting the effective doping of N into the carbon lattice. The strong interaction between SiO2 nanoparticles and the polysulfides is also confirmed by visual discrimination. As shown in Figure 2d, the equivalent mass of the C and C/SiO2 membranes (10 mg) was added into the same concentration (10 mM) and volume (3 ml) of Li2S6 solution. The solution including C/SiO2 membranes was colorless due to the strong chemisorption of SiO2 to LiPSs, while the solution containing C membranes was deep yellow. To further verify the strong interaction between SiO2 and LiPSs, theoretical simulations based on DFT were carried out. Different Li2Sx (x=1, 2, 4, 6) absorbed on the most stable (002) plane of SiO2 were calculated in Figure 2e. The red, gray, purple, and orange balls represent oxygen, sulfur, lithium, and silicon atoms, respectively. The absorption 10 ACS Paragon Plus Environment
Page 10 of 27
Page 11 of 27 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
ACS Nano
energies between Li2S, Li2S2, Li2S4 and Li2S6 species with SiO2 nanocrystals are -11.78, 9.51, -11.60 and -10.67 eV, respectively. These values are higher than other polysulfide reservoirs in previous reports.49 It is evident that the S and Li atoms bonded readily with O and N atoms to form S-O and Li-N bonds,50 which is quite different from the dipole-dipole interaction between the LiPSs and pristine C membrane. These calculations are consistent with the XPS results discussed above.
Figure 2. (a) XRD patterns of SiO2 nanoparticles, C membranes, C/SiO2 composite membranes and S loaded C/SiO2 membranes; (b) S 2p spectrum of S loaded C/SiO2 membrane cathode at discharged state; (c) N 1s spectrum of C/SiO2 and S loaded C/SiO2 membranes; (d) strong interaction between SiO2 nanoparticles and LiPSs by a visual discrimination; and (e) theoretical DFT simulation of the interaction between SiO2 and LiPSs.
To evaluate the electrochemical properties of the C/SiO2 membrane as a sulfur host material, 2025-type coin cells with three kinds of cathodes, namely, Al, C membranes and C/SiO2 membranes, were assembled in a glove box. Figure 3a shows the cyclic voltammetry (CV) curves of the three cathodes measured at a scan rate of 0.05 mV/s from 1.7 V to 2.8 V 11 ACS Paragon Plus Environment
ACS Nano 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
(vs. Li/Li+). There are two strong and sharp peaks at 2.31 V and 2.03 V in the cathodic scanning of the C/SiO2 membrane cathode, and the former corresponds to the transition from sulfur to LiPSs (Li2Sx, 4 < x ≤ 8), and the latter corresponds to the subsequent reduction of LiPSs to short-chain Li2S2 and Li2S. Furthermore, in the anodic scanning, shoulders near 2.37 V and 2.42 V are related to the oxidation reaction from Li2S/Li2S2 to LiPSs and eventually to S8.
51,52
The reduction peak at approximately 2.03 V, related to the conversion of long-chain
LiPSs to short-chain LiPSs, shows the highest peak current in the CV curves for the C/SiO2 membranes compared to the C membranes and Al foil cathodes, indicating that the polysulfide redox reaction kinetics were promoted by the introduction of SiO2 nanoparticles. Moreover, the apparent positive shift in the reduction characteristic peaks and negative shift in the oxidation characteristic peaks can be ascribed to adequate electrolyte permeation and fast kinetic reactions in the composite membranes. The typical charge-discharge curves of the three kinds of electrodes at 0.1 C are displayed in Figure 3b. The two discharge plateaus for the three cathodes are consistent with the CV curves. It is noted that the C/SiO2 membranes had the lowest overpotential (ΔE) value of 168 mV at 0.1 C compared with 186 mV for the C membranes and 176 mV for the Al cathode; this indicates fast electron and ion transport resulting from the hierarchical porous structure in the composite membranes, which provides intimate contact with the electrolyte for the LiPSs redox electrochemical reaction. The nanosized SiO2 as LiPSs reservoirs mitigate the “shuttle effect” by means of polar-polar chemical absorption, preventing the leakage of active lithium polysulfide species and resulting in favorable and stable reaction kinetics. In Figure 3c and Figure S 7a-c, the C/SiO2 membranes show a high rate performance and excellent capacity retention. The average specific capacity values of 1050, 935, 855, 767, and 649 mA h g-1 were measured at 0.1, 0.2, 0.5, 1, and 2 C (1 C=1675 mA h g-1), respectively, which are higher than that for C membranes and Al cathodes. In particular, the reversible capacity of 927 mA h g-1 was obtained when the current density switched back to 12 ACS Paragon Plus Environment
Page 12 of 27
Page 13 of 27 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
ACS Nano
0.1 C (Figure 3c). In Figure 3d and e, the C/SiO2 membranes with sulfur loading of 1.5 and 2.8 mg cm-2, and C membranes and Al cathodes with sulfur loading of 1.5 mg cm-2 were measured at 0.2 C and 1 C to investigate the cycle performance of these electrodes. An initial discharge capacity of 1229 mA h g-1 for C/SiO2 cathodes (1.5 mg cm-2) was delivered during the activation process, and the subsequent residual capacity was 717 mA h g-1 (0.2 C) after 200 cycles with a good coulombic efficiency (~98.7%) and a decay rate of 0.21% per cycle (Figure 3d). At the same time, the initial discharge capacity of 1089 mA h g-1 and the retained capacity of 699 mA h g-1 at 0.2 C after 200 cycles were obtained, with a coulombic efficiency of 96.8% for high sulfur loading of 2.8 mg cm-2, indicating better cycling stability with only a modest outward diffusion of LiPSs to some degree. In addition, when measured at a high current rate of 1 C (Figure 3e), the capacity decay rate is 0.13% and 0.16% per cycle after 300 cycles for low (1.5 mg cm-2) and high (2.8 mg cm-2) sulfur loading cathodes, respectively, showing good cycling stability similar to those at a low current rate (0.2 C). In sharp contrast, the other two cathodes retained capacities of 569 and 497 mA h g-1 at 0.2 C after 200 cycles, and values of 501 and 292 mA h g-1 at 1 C after 300 cycles, indicating a serious “shuttle effect” and poor cycling performance. In fact, long-term cycling stability was also measured under 0.5 C and 1 C with a sulfur loading of 1.5 mg cm-2 (Figure S 7d, e), and the C/SiO2 membrane cathode exhibits the highest cycling performance among the electrodes. Discharge capacities of 614 mA h g-1 for 300 cycles and 573 mA h g-1 for 600 cycles at 1C were obtained, with the capacity retention of 75.2% and 70.1%, respectively, demonstrating that the LiPSs shuttle was well mitigated from the effective interfacial interaction between the C/SiO2 membrane and LiPSs. High areal sulfur loading is an important issue for energy storage systems in practical applications.53,54 The areal capacity of these electrodes was calculated in Figure 3f, and an areal capacity of approximately 1.6 mAh cm-2 at 1C and a high sulfur loading of 2.8 mg cm-2 were retained after 300 cycles, indicating that the porous C/SiO2 membranes are suitable sulfur host materials for high-energy-density Li-S systems. 13 ACS Paragon Plus Environment
ACS Nano 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
Figure 3g and h shows that more than 30 blue or green light-emitting diodes were lighted with two coin cells, showing that Li-S batteries based on flexible C/SiO2 membranes are promising candidates for future commercial applications due to their facile large-scale production and lower cost than conventional GO/graphene and carbon nanotube electrode materials.
Figure 3. (a) CV curves of Al, C membranes and C/SiO2 membrane electrodes; (b) typical chargedischarge curves of different cathodes at 0.1 C; (c) rate performance of different cathodes; (d, e) cycling performance of different cathodes at sulfur loading of 1.5 and 2.8 mg cm-2; (f) areal capacity of different cathodes; and (g, h) more than 30 blue or green light-emitting diodes were lighted with two coin cells.
In this work, the filling of most S in the macropores of C/SiO2 membranes is crucial for the high capacity and stable cycling performance of Li-S batteries. For the controlled 14 ACS Paragon Plus Environment
Page 14 of 27
Page 15 of 27 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
ACS Nano
electrode with a S slurry coating of 1.5 mg cm-2 on the C/SiO2 membrane, however, poor rate performance and cycling stability were obtained, which can be ascribed to the serious “shuttle effect” of LiPSs and slow diffusion of ions/electrolyte in the thick S slurry layer (Figure S8). In contrast, the rationally designed triple-layer-structured porous C/SiO2 membranes enable filling of most S species in the macropores and have a thin S slurry loading on the membrane surface. The hierarchical macropores can alleviate the volume expansion of sulfur species and facilitate ion/electrolyte transport for fast kinetics, and the thin S slurry coating allows fast ion diffusion; thus, a high energy density, high rate performance and stable cycling stability were obtained for the C/SiO2 membrane electrodes. In addition, electrochemical impedance spectroscopy (EIS) studies of Li-S batteries with the C/SiO2 composite membrane and Al foil as cathodes were obtained (Figure S9). From the Nyquist plots, a semicircular curve in the high frequency region and a sloped line in the low-frequency region were obtained respectively for the two cathodes, corresponding to the charge-transfer resistance and ion diffusion resistance, respectively. The smaller semicircular loop of the C/SiO2 composite membrane suggests its enhanced charge-transfer capability due to its continuously porous support carbon structure. Moreover, the large slope of the C/SiO2 composite membrane at low frequency revealed fast ion transport in the membrane electrode. The Nyquist plot further confirmed that the well-designed hierarchical porous membrane had ideal ion transport paths. To prove the stability of C/SiO2 membranes after long-term cycles, the coin cells were disassembled after 600 cycles (1C) to investigate the variation in the pore structure in C/SiO2 membrane cathodes. It can be observed that the large macropores show good integrity without pore structural collapse compared to the original C/SiO2 membranes (Figure 4a), verifying a robust structural strength and good permeation of ions/electrolyte, thus resulting in high cycling stability and fast reaction kinetics. Although the sulfur slurry coating became looser and thicker (~15 µm) after cycling compared to the original sulfur slurry layer (~8 µm, Figure 1f), the coating still adhered well to the C/SiO2 membrane surface through the sponge15 ACS Paragon Plus Environment
ACS Nano
(a) 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
like porous layer. The sulfur slurry layer on the C/SiO2 membrane surface with uniform sulfur dispersion was further confirmed from the top surface of the composite membranes (Figure 4b, c). Accordingly, the stable cycling stability and high energy density of the C/SiO2 membrane electrodes are ascribed to the improved sulfur loading by simultaneous filling of the main sulfur in the pores, the additional coating of the sulfur slurry on the surface that facilitated ion diffusion in the porous structure, and the strong chemisorption between the doped SiO2 nanoparticles and LiPSs. In particular, the cross-sectional SEM image and EDX element maps (Figure 4d-i) show that the S species and other elements were detected throughout the entire membrane with uniform distribution, indicating close contact between the conductive carbon membranes and insulating sulfur species to achieve the maximum specific capacity and chemisorption ability.
Figure 4. (a-c) S slurry coating adhered well to the membrane surface even after 600 cycles (1C) for the C/SiO2 membrane electrodes. (d-i) The cross-sectional SEM image and EDX element maps show that the S and other elements are uniformly dispersed throughout the membranes.
Conclusion In summary, delicate triple-layer-structured porous C/SiO2 membranes were designed to advance Li-S battery technology. The large macropores in the membrane accommodated most of the S species and facilitated ion/electrolyte transport for fast reaction kinetics. The spongelike porous membrane surface allowed the S slurry coating to increase the S loading mass to 16 ACS Paragon Plus Environment
Page 16 of 27
Page 17 of 27 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
ACS Nano
2.8 mg cm-2 with a sulfur content of ~75% in the cathode. The dense layer of C/SiO2 membranes can replace Al foil and work as a current collector. DFT simulations and visual adsorption measurements confirmed that the doped SiO2 nanoparticles played a critical role in suppressing the shuttle effect of polysulfides via chemisorption and electrocatalysis. The hierarchically porous C/SiO2 membrane cathodes delivered a high capacity of ~700 mA h g-1 at 0.2 C after 200 cycles, even at a high sulfur loading of 2.8 mg cm-2 with a coulombic efficiency ~97%, and the areal capacity still approached 1.6 mAh cm-2 at 1.0 C after 300 cycles. Due to its simple preparation process, this scalable yet flexible self-supporting cathode design presents a useful strategy for realizing practical applications of high-energy-density LiS batteries. We believe that different polar-metal-oxide-doped carbon membranes can be fabricated by the reported approach for Li-S batteries, Li-ion batteries and other electrocatalysis applications.
Methods Preparation of C and C/SiO2 membranes The SiO2/C membrane was prepared by a phase inversion method followed by carbonization. First, 6 g SiO2 (10-20 nm, Aladdin) nanoparticles was dispersed in 34 g N,Ndimethylformamide (DMF, Aladdin, >99.9%) under magnetic stirring for 2 h to form a homogenous suspension. Next, 6 g polyacrylonitrile (PAN, MW=40000, Aladdin, > 99%) was dissolved in the above suspension (15 wt%) at 80 ℃ in an oil bath. Then, the internal bubble was removed in the mixture by centrifugation at 5000 rpm for 10 min, and the viscous mixture was coated on a glass plate with a thickness of ~150 µm by an automatic scraping knife (Video 1, the thickness was varied by adjusting the scraping knife). Subsequently, the precursor solution-coated glass plate was rapidly immersed into deionized water (DI water) for solvent exchange and phase inversion to form asymmetric PAN/SiO2 membranes. The 17 ACS Paragon Plus Environment
ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 18 of 27
obtained white PAN/SiO2 membrane was dried overnight under a vacuum oven at 90℃, with subsequent preoxidation at 250℃ in a muffle furnace with a ramp rate of 2℃/min to enhance the membrane mechanical strength. To ensure carbonization of the membrane, it was further carbonized in Ar at 700 ℃ for 1 h (5 ℃ min-1) to obtain a C/SiO2 membrane. The pure C membrane was also prepared by the same process. S loading in the C and C/SiO2 membrane electrodes The C/S slurry was prepared by a melt-diffusion method. The super P and sulfur powder at a mass ratio of 1.8:1 were ground in an agate mortar for 30 min. Then, the mixture was transferred to a vessel filled with argon and heated at 155℃ for 12 h. After cooling to room temperature, 90 mg of the obtained C/S hybrid was mixed with 10 mg of polyvinylidene fluoride (PVDF-5130) binder in 700 µl NMP to form an electrode material slurry, in which the weight fraction of active material sulfur was approximately 60%. A solution (S/CS2) consisting of 100 mg sulfur powder, 7 ml CS2 and 5 ml anhydrous ethanol was also prepared. The as-prepared C/SiO2 membrane was cut into circular discs with a diameter of 14 mm (1.54 cm-2), and the desired amount of S/CS2 solution was first infiltrated into the macropores of the C/SiO2 membrane. These sulfur-impregnated discs were dried at 40℃ and transferred into a Teflon-lined autoclave vessel in argon at a heating temperature of 155℃. Then, the C/S slurry was uniformly coated onto the membrane surface to further increase sulfur loading. For comparison, C membrane and traditional Al electrodes were also prepared by coating C/S slurry directly. Characterization The morphology and EDX element maps were visualized by scanning electron microscopy (Nova Nano SEM 450). The crystal phase was measured by X-ray diffraction (XRD, D/MAX-2400, Cu Kα λ = 1.5406 Å). A thermogravimetric analyzer (TA Instruments Q50 TGA) was employed to analyze the mass percentage of SiO2 or sulfur at a heating rate of 10℃ 18 ACS Paragon Plus Environment
Page 19 of 27 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
ACS Nano
/min. X-ray photoelectron spectroscopy (XPS, ESCALAB 250 Xi) was carried out to validate the interaction between SiO2 and LiPSs, with an energy step of 1 eV for the survey and 0.05 eV for the individual characteristic peak. Fourier transform infrared spectrometry (FTIR, Thermo Fisher, 6700) was performed to detect the functional groups of C and C/SiO2 membranes. A Raman shift (Thermo Fisher, DXR Smart Raman) was collected to investigate the graphitizing extent. The polysulfide absorbance study was carried out by adding C or C/SiO2 (10 mg, respectively) to 3 ml of 10 mM Li2S6 solution and then statically maintained for 12 h to observe color variation. To theoretically investigate the absorbability of SiO2 to LiPSs, all calculations based on density functional theory (DFT) were carried out with the Material Studio modeling Dmol3 package. Double numerical plus polarization function (the DNP basis set) and the generalized gradient approximation (GGA) with PBE function were used in all calculations. Electrochemical measurements The electrochemical properties of the C/SiO2 membrane, C membrane and traditional Al cathode were evaluated via CR2025 coin-type cells directly assembled in an argon-filled glove
box
using
lithium
plate
(74
mg,
~2
cm2)
as
the
anode
and
polypropylene/polyethylene/polypropylene membrane (PP/PE/PP, Celgard) as the separator. A nonaqueous solution (1:1 for 1,2-Dimethoxyethane and 1,3-dioxolane) with 1 M LiTFSI was used as the electrolyte. The cycling performance and charge-discharge were measured using a LAND CT2001A multichannel battery test system in the voltage range of 1.7 to 2.8 V (vis. Li/Li+). For the rate capacity measurement, 10 cycles charge-discharge for each current density of 0.1, 0.2, 0.5, 1 and 2 C (1 C=1675 mA h g-1) was tested and subsequently returned to 0.1 C to finish. Cyclic voltammetry (CV) curves were tested on an Ivium Powerstat (Ivium Technologies, the Netherlands) electrochemical workstation at a scan rate of 0.05 mV s−1.
19 ACS Paragon Plus Environment
ACS Nano 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
Supporting Information. The Supporting Information is available free of charge on the ACS Publications website at http://pubs.acs.org. SEM images of C/SiO2 membranes and the microstructure (Fig. S1), PAN/SiO2 and preoxidized PAN/SiO2 membranes (Fig. S2), surface structure of C/SiO2 membranes and TGA analysis (Fig. S3), C/SiO2 membranes with different SiO2 contents (Fig. S4), S loaded C/SiO2 membranes (Fig. S5), S loading analysis (Fig. S6), charge-discharge curves of different electrodes (Fig. S7), cycling stability and rate performance (Fig. S8), Nyquist plots of Li–S cells (Fig. S9). Structure parameters of the membranes (Tab. S1), and sulfur loading and electrolyte/sulfur ratio comparison with published results (Tab. S2).
Acknowledgements X.L. and G.H. acknowledge the funding support from Natural Science Foundation of China (21476044, 21676043, 21506028, 21706023), Fundamental Research Funds for the Central Universities (DUT15QY08), as well as from Changjiang Scholars Program (T2012049). G.Y. acknowledges support from the National Science Foundation grant (NSF-CMMI-1537894).
References (1)
Peng, H.-J.; Hou, T.-Z.; Zhang, Q.; Huang, J.-Q.; Cheng, X.-B.; Guo, M.-Q.; Yuan, Z.;
He, L.-Y.; Wei, F. Strongly Coupled Interfaces Between a Heterogeneous Carbon Host and a Sulfur-Containing Guest for Highly Stable Lithium-Sulfur Batteries: Mechanistic Insight into Capacity Degradation. Adv. Mater. Interfaces 2014, 1, 1400227. (2)
Yin, Y. X.; Xin, S.; Guo, Y. G.; Wan, L. J. Lithium-Sulfur Batteries:
Electrochemistry, Materials, and Prospects. Angew. Chem. Int. Ed. 2013, 52, 13186-13200. (3)
Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J. M. Li-O2 and Li-S
Batteries with High Energy Storage. Nat. Mater. 2011, 11, 19-29. 20 ACS Paragon Plus Environment
Page 20 of 27
Page 21 of 27 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
ACS Nano
(4)
Zhou, G.; Li, L.; Ma, C.; Wang, S.; Shi, Y.; Koratkar, N.; Ren, W.; Li, F.; Cheng, H.-
M. A Graphene Foam Electrode with High Sulfur Loading for Flexible and High Energy Li-S Batteries. Nano Energy 2015, 11, 356-365. (5)
Ji, X.; Evers, S.; Black, R.; Nazar, L. F. Stabilizing Lithium-Sulphur Cathodes Using
Polysulphide Reservoirs. Nat. Commun. 2011, 2, 325. (6)
Tao, X.; Wang, J.; Liu, C.; Wang, H.; Yao, H.; Zheng, G.; Seh, Z. W.; Cai, Q.; Li, W.;
Zhou, G. Balancing Surface Adsorption and Diffusion of Lithium-Polysulfides on Nonconductive Oxides for Lithium-Sulfur Battery Design. Nat. Commun. 2016, 7, 11203. (7)
Zhang, J.; Huang, H.; Bae, J.; Chung, S.-H.; Zhang, W.; Manthiram, A.; Yu, G.
Nanostructured Host Materials for Trapping Sulfur in Rechargeable Li-S Batteries: Structure Design and Interfacial Chemistry. Small Methods 2018, 2, 1700279. (8)
Zhang, J.; Shi, Y.; Ding, Y.; Peng, L.; Zhang, W.; Yu, G. A Conductive Molecular
Framework Derived Li2S/N,P-Codoped Carbon Cathode for Advanced Lithium-Sulfur Batteries. Adv. Energy Mater. 2017, 7, 1602876. (9)
Zhang, J.; Shi, Y.; Ding, Y.; Zhang, W.; Yu, G. In Situ Reactive Synthesis of
Polypyrrole-MnO2 Coaxial Nanotubes as Sulfur Hosts for High-Performance Li–Sulfur Battery. Nano Lett. 2016, 16, 7276-7281. (10)
Li., Z.; Jiang., Y.; Yuan., L.; Huang., Y. A Highly Ordered Meso@Microporous
Carbon-Supported Sulfur@Smaller Sulfur Core-Shell Structured Cathode for Li-S Batteries. ACS Nano 2014, 8, 9295-9303. (11)
Jayaprakash, N.; Shen, J.; Moganty, S. S.; Corona, A.; Archer, L. A. Porous Hollow
Carbon@Sulfur Composites for High-Power Lithium-Sulfur Batteries. Angew. Chem. Int. Ed. 2011, 50, 5904-5908. (12)
Zhou, W.; Xiao, X.; Cai, M.; Yang, L. Polydopamine-Coated, Nitrogen-Doped,
Hollow Carbon-Sulfur Double-Layered Core-Shell Structure for Improving Lithium-Sulfur Batteries. Nano. Lett. 2014, 14, 5250-5256. 21 ACS Paragon Plus Environment
ACS Nano 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
(13)
Peng, L.; Fang, Z.; Zhu, Y.; Yan, C.; Yu, G. Holey Two-Dimensional Nanomaterials
for Electrochemical Energy Storage. Adv. Energy Mater. 2018, 8, 1702179. (14)
Li, Z.; Zhang, J.; Lou, X. W. Hollow Carbon Nanofibers Filled with MnO2 Nanosheets
as Efficient Sulfur Hosts for Lithium-Sulfur Batteries. Angew. Chem. Int. Ed. 2015, 54, 12886-12890. (15)
Zuo, P.; Zhang, H.; He, M.; Li, Q.; Ma, Y.; Du, C.; Cheng, X.; Huo, H.; Gao, Y.; Yin,
G. Clew-Like N-Doped Multiwalled Carbon Nanotube Aggregates Derived from MetalOrganic Complexes for Lithium-Sulfur Batteries. Carbon 2017, 122, 635-642. (16)
Ji, L.; Rao, M.; Zheng, H.; Zhang, L.; Li, Y.; Duan, W.; Guo, J.; Cairns, E. J.; Zhang,
Y. Graphene Oxide as a Sulfur Immobilizer in High Performance Lithium/Sulfur Cells. J. Am. Chem. Soc. 2011, 133, 18522-18525. (17)
Shi, Y.; Wen, L.; Zhou, G.; Chen, J.; Pei, S.; Huang, K.; Cheng, H.-M.; Li, F.
Graphene-Based Integrated Electrodes for Flexible Lithium Ion Batteries. 2D Mater. 2015, 2, 024004. (18)
Song, X.; Wang, S.; Bao, Y.; Liu, G.; Sun, W.; Ding, L.-X.; Liu, H.; Wang, H. A High
Strength, Free-Standing Cathode Constructed by Regulating Graphitization and the Pore Structure in Nitrogen-Doped Carbon Nanofibers for Flexible Lithium–Sulfur Batteries. J. Mater. Chem. A 2017, 5, 6832-6839. (19)
Choudhury, S.; Fischer, D.; Formanek, P.; Simon, F.; Stamm, M.; Ionov, L. Porous
Carbon Prepared from Polyacrylonitrile for Lithium-Sulfur Battery Cathodes Using Phase Inversion Technique. Polymer 2018, 151, 171-178. (20)
Li, Z.; Zhang, J.; Guan, B.; Wang, D.; Liu, L. M.; Lou, X. W. A Sulfur Host Based on
Titanium Monoxide@Carbon Hollow Spheres for Advanced Lithium-Sulfur Batteries. Nat. Commun. 2016, 7, 13065. (21)
He, J.; Luo, L.; Chen, Y.; Manthiram, A. Yolk-Shelled C@Fe3O4 Nanoboxes as
Efficient Sulfur Hosts for High-Performance Lithium-Sulfur Batteries. Adv. Mater. 2017, 29, 22 ACS Paragon Plus Environment
Page 22 of 27
Page 23 of 27 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
ACS Nano
1702707. (22)
Ma, L.; Chen, R.; Zhu, G.; Hu, Y.; Wang, Y.; Chen, T.; Liu, J.; Jin, Z. Cerium Oxide
Nanocrystal Embedded Bimodal Micromesoporous Nitrogen-Rich Carbon Nanospheres as Effective Sulfur Host for Lithium-Sulfur Batteries. ACS Nano 2017, 11, 7274-7283. (23)
Liu, X.; Huang, J. Q.; Zhang, Q.; Mai, L. Nanostructured Metal Oxides and Sulfides
for Lithium-Sulfur Batteries. Adv. Mater. 2017, 29, 471003. (24)
Zhang, X.; Yang, H.; Guo, J.; Zhao, S.; Gong, S.; Du, X.; Zhang, F. Nitrogen-Doped
Hollow Porous Carbon Nanospheres Coated with MnO2 Nanosheets as Excellent Sulfur Hosts for Li-S Batteries. Nanotechnol. 2017, 28, 475401. (25)
Liu, T.; Sun, X.; Sun, S.; Niu, Q.; Liu, H.; Song, W.; Cao, F.; Li, X.; Ohsaka, T.; Wu,
J. A Robust and Low-Cost Biomass Carbon Fiber@SiO2 Interlayer for Reliable LithiumSulfur Batteries. Electrochim. Acta 2019, 295, 684-692. (26)
Wu, H.; Tang, Q.; Fan, H.; Liu, Z.; Hu, A.; Zhang, S.; Deng, W.; Chen, X. Dual-
Confined and Hierarchical-Porous Graphene/C/SiO2 Hollow Microspheres through Spray Drying Approach for Lithium-Sulfur Batteries. Electrochim. Acta 2017, 255, 179-186. (27)
Xiao, Z.; Yang, Z.; Wang, L.; Nie, H.; Zhong, M.; Lai, Q.; Xu, X.; Zhang, L.; Huang,
S. A Lightweight TiO2/Graphene Interlayer, Applied as a Highly Effective Polysulfide Absorbent for Fast, Long-Life Lithium-Sulfur Batteries. Adv. Mater. 2015, 27, 2891-2898. (28)
Song, X.; Wang, S.; Chen, G.; Gao, T.; Bao, Y.; Ding, L.-X.; Wang, H. Fe-N-Doped
Carbon Nanofiber and Graphene Modified Separator for Lithium-Sulfur Batteries. Chem. Eng. J. 2018, 333, 564-571. (29)
Zhang, S. S. Liquid Electrolyte Lithium/Sulfur Battery: Fundamental Chemistry,
Problems, and Solutions. J. Power Sources 2013, 231, 153-162. (30)
Fu, K.; Gong, Y.; Hitz, G. T.; McOwen, D. W.; Li, Y.; Xu, S.; Wen, Y.; Zhang, L.;
Wang, C.; Pastel, G. Three-Dimensional Bilayer Garnet Solid Electrolyte Based High Energy Density Lithium Metal–Sulfur Batteries. Energy Environ. Sci. 2017, 10, 1568-1575. 23 ACS Paragon Plus Environment
ACS Nano 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
(31)
Xiao, L.; Cao, Y.; Xiao, J.; Schwenzer, B.; Engelhard, M. H.; Saraf, L. V.; Nie, Z.;
Exarhos, G. J.; Liu, J. A Soft Approach to Encapsulate Sulfur: Polyaniline Nanotubes for Lithium-Sulfur Batteries with Long Cycle Life. Adv. Mater. 2012, 24, 1176-1181. (32)
Preefer, M. B.; Oschmann, B.; Hawker, C. J.; Seshadri, R.; Wudl, F. High Sulfur
Content Material with Stable Cycling in Lithium-Sulfur Batteries. Angew. Chem. Int. Ed. 2017, 56, 15118-15122. (33)
Wu, F.; Chen, S.; Srot, V.; Huang, Y.; Sinha, S. K.; van Aken, P. A.; Maier, J.; Yu, Y.
A Sulfur-Limonene-Based Electrode for Lithium-Sulfur Batteries: High-Performance by SelfProtection. Adv. Mater. 2018, 30, 1706643. (34)
Zhou, G.; Zhao, Y.; Zu, C.; Manthiram, A. Free-Standing TiO2 Nanowire-Embedded
Graphene Hybrid Membrane for Advanced Li/Dissolved Polysulfide Batteries. Nano Energy 2015, 12, 240-249. (35)
Chung, S.-H.; Manthiram, A. Carbonized Eggshell Membrane as a Natural Polysulfide
Reservoir for Highly Reversible Li-S Batteries. Adv. Mater.2014, 26, 1360-1365. (36)
Chung, S.-H.; Manthiram, A. Low-Cost, Porous Carbon Current Collector with High
Sulfur Loading for Lithium–Sulfur Batteries. Electrochem. Commun. 2014, 38, 91-95. (37)
Chen, W.; Zhang, Z.; Li, Q.; Lai, Y.; Li, J. Freestanding Sulfur/3D Carbon Fiber
Membrane Cathodes for Advanced Lithium-Sulfur Batteries. Chemelectrochem 2015, 2, 246252. (38)
Sun, L.; Li, M.; Jiang, Y.; Kong, W.; Jiang, K.; Wang, J.; Fan, S. Sulfur Nanocrystals
Confined in Carbon Nanotube Network as a Binder-Free Electrode for High-Performance Lithium Sulfur Batteries. Nano Lett. 2014, 14, 4044-4049. (39)
Hołda, A. K.; Vankelecom, I. F. J. Understanding and Guiding the Phase Inversion
Process for Synthesis of Solvent Resistant Nanofiltration Membranes. J. Appl. Polym. Sci. 2015, 132, 42130. (40)
Fang, R.; Zhao, S.; Sun, Z.; Wang, D. W.; Cheng, H. M.; Li, F. More Reliable 24 ACS Paragon Plus Environment
Page 24 of 27
Page 25 of 27 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
ACS Nano
Lithium-Sulfur Batteries: Status, Solutions and Prospects. Adv. Mater. 2017, 29, 1606823. (41)
Pang, Q.; Tang, J.; Huang, H.; Liang, X.; Hart, C.; Tam, K. C.; Nazar, L. F. A
Nitrogen and Sulfur Dual-Doped Carbon Derived from Polyrhodanine@Cellulose for Advanced Lithium-Sulfur Batteries. Adv. Mater. 2015, 27, 6021-6028. (42)
Xiang, M.; Wu, H.; Liu, H.; Huang, J.; Zheng, Y.; Yang, L.; Jing, P.; Zhang, Y.; Dou,
S.; Liu, H. A Flexible 3D Multifunctional Mgo-Decorated Carbon Foam@Cnts Hybrid as Self-Supported Cathode for High-Performance Lithium-Sulfur Batteries. Adv. Funct. Mater. 2017, 27, 1702573. (43)
Li, X.; John, V. T.; He, G.; He, J.; Spinu, L. Magnetic TiO2–SiO2 Hybrid Hollow
Spheres with TiO2 Nanofibers on the Surface and Their Formation Mechanism. J. Mater. Chem. 2012, 22, 17476-17484. (44)
Liang, X.; Hart, C.; Pang, Q.; Garsuch, A.; Weiss, T.; Nazar, L. F. A Highly Efficient
Polysulfide Mediator for Lithium-Sulfur Batteries. Nat. Commun. 2015, 6, 5682. (45)
Xue, W.; Yan, Q.-B.; Xu, G.; Suo, L.; Chen, Y.; Wang, C.; Wang, C.-A.; Li, J.
Double-Oxide Sulfur Host for Advanced Lithium-Sulfur Batteries. Nano Energy 2017, 38, 12-18. (46)
Fu, Y.; Su, Y.-S.; Manthiram, A. Highly Reversible Lithium/Dissolved Polysulfide
Batteries with Carbon Nanotube Electrodes. Angew. Chem. Int. Ed. 2013, 52, 6930-6935. (47)
Qu., L.; Liu., Y.; Baek., J.-B.; Dai., L. Nitrogen-Doped Graphene as Efficient Metal-
Free Electrocatalyst for Oxygen Reduction in Fuel Cells. ACS Nano 2010, 4, 1321-1326. (48)
Lv, R.; Cui, T.; Jun, M.-S.; Zhang, Q.; Cao, A.; Su, D. S.; Zhang, Z.; Yoon, S.-H.;
Miyawaki, J.; Mochida, I. Open-Ended, N-Doped Carbon Nanotube-Graphene Hybrid Nanostructures as High-Performance Catalyst Support. Adv. Funct. Mater. 2011, 21, 9991006. (49)
Rehman, S.; Tang, T.; Ali, Z.; Huang, X.; Hou, Y. Integrated Design of MnO2
@Carbon Hollow Nanoboxes to Synergistically Encapsulate Polysulfides for Empowering 25 ACS Paragon Plus Environment
ACS Nano 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
Lithium Sulfur Batteries. Small 2017, 13, 1700087. (50)
Tao, X.; Wang, J.; Ying, Z.; Cai, Q.; Zheng, G.; Gan, Y.; Huang, H.; Xia, Y.; Liang,
C.; Zhang, W.; Cui, Y. Strong Sulfur Binding with Conducting Magneli-Phase TiNO2N-1 Nanomaterials for Improving Lithium-Sulfur Batteries. Nano. Lett. 2014, 14, 5288-5294. (51)
Xu, R.; Lu, J.; Amine, K. Progress in Mechanistic Understanding and Characterization
Techniques of Li-S Batteries. Adv. Energy. Mater. 2015, 5, 1500408. (52)
Peng, H.-J.; Huang, J.-Q.; Zhao, M.-Q.; Zhang, Q.; Cheng, X.-B.; Liu, X.-Y.; Qian,
W.-Z.; Wei, F. Nanoarchitectured Graphene/Cnt@Porous Carbon with Extraordinary Electrical Conductivity and Interconnected Micro/Mesopores for Lithium-Sulfur Batteries. Adv. Funct. Mater. 2014, 24, 2772-2781. (53)
Miao, L.; Wang, W.; Yuan, K.; Yang, Y.; Wang, A. A Lithium-Sulfur Cathode with
High Sulfur Loading and High Capacity Per Area: A Binder-Free Carbon Fiber Cloth-Sulfur Material. Chem. Commun. 2014, 50, 13231-13234. (54)
Hagen, M.; Dörfler, S.; Fanz, P.; Berger, T.; Speck, R.; Tübke, J.; Althues, H.;
Hoffmann, M. J.; Scherr, C.; Kaskel, S. Development and Costs Calculation of Lithium– Sulfur Cells with High Sulfur Load and Binder Free Electrodes. J. Power Sources 2013, 224, 260-268.
26 ACS Paragon Plus Environment
Page 26 of 27
Page 27 of 27 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
ACS Nano
TABLE OF CONTENT
27 ACS Paragon Plus Environment
