Built Structure of Ordered Vertically Aligned Codoped Carbon

Research Article www.acsami.org

Built Structure of Ordered Vertically Aligned Codoped Carbon Nanowire Arrays for Supercapacitors Jing Li, Guofeng Zhang, Nan Chen,* Xiaowei Nie, Bingxue Ji, and Liangti Qu* Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China S Supporting Information *

ABSTRACT: We report an ingenious yet efficient method to fabricate ordered vertically aligned nitrogen- and sulfur-codoped carbon nanowire (NS-CNW) arrays by direct carbonization of the finely designed copolymer. The asprepared vertically aligned NS-CNWs with unique electronic features and very narrow diameters facilitate ion diffusion to further exhibit ideal electrochemical properties (243.0 F g−1 at the current density of 0.1 A g−1) and excellent cycle stability (10 000 cycles) when applied to a supercapacitor electrode. The controllable design and copolymerization of conducting polymers, which can provide doped carbon nanowire array electrodes having high surface area with controllable components and uniform dimensions in a neat way, provide more flexibility to tailor the carbon-based electrodes toward specific applications. KEYWORDS: codoped carbon nanowire, copolymerization, EDOT, pyrrole, supercapacitor

■

INTRODUCTION Along with the growing field of advanced energy conversion and storage, electrochemical capacitors, as promising energystorage devices, have generated considerable attraction because of their reasonably high energy density, combined with a high power-delivery capability.1,2 Moreover, supercapacitors possess an advantage of fast charging and discharging compared with battery systems. To the best of our knowledge, a large number of materials are needed to have high electrical conductivity when they are synthesized as electrode materials in supercapacitors. In general, they can be classified into conducting polymers, metal oxides, and carbon materials, etc.3 Electrodes with redoxactive materials made from conducting polymers or electroactive metal oxides always have high specific capacitance values because of pseudocapacitance. Sadly, expansion and contraction for conducting polymers may occur in the process of intercalating and deintercalating, resulting in mechanical and electrochemical degradation. Regarding metal oxides, the fact that they are high-cost and unfriendly to the environment still prevents their practical application. Carbon-based materials are active in the vast areas of adsorption, water purification, catalysis, and electronics, and especially in energy conversion and storage fields because of their fascinating physical properties.4−6 The merits of carbon materials lie in their nontoxicity, high chemical stability, lower cost than that of metal oxides, pretty good electronic conductivity, higher specific surface area, and easy processing. The doping of heteroatoms is conductive for carbon-based materials not only to adsorb ions but also to improve the © XXXX American Chemical Society

hydrophilicity and lipophilicity, ultimately resulting in rapid ion transport. Thus, carbon materials provide a most likely effective way of enhancing the capacitance by introducing, for example, N, P, and S heteroatoms.7,8 Furthermore, the unique electronic features and distinctive synergistic effect depend on the codoping of heteroatoms with different electronegativities, which had an incomparable superiority to single-componentdoping. So far, more and more research concentrates on the dual-heteroatom-doped carbon, including B- and N-codoped,9 and N- and P-codoped carbon,10 etc. The heteroatoms of the codoped carbon can effectively enhance the electrochemical properties via the synergistic effects based on both the theoretical calculations and electrochemical characterization.11 Unfortunately, the preparation of heteroatom-doped carbon materials is restricted to carbonization of only a significant minority of conventional organic precursors. It can be interpreted that most carbonaceous precursors that are lowmolecular-weight organics are completely decomposed or evaporated into gas before or during the process of hightemperature carbonization. Fortunately, the carbonization of designated structural polymers provides a clever path for the construction of selected-heteroatom-doped carbon materials. The method of precisely controlling electrochemical codeposition possibly provides a unique opportunity, which can achieve the production of advanced multiple-component modified carbons. Received: April 17, 2017 Accepted: June 30, 2017 Published: June 30, 2017 A

DOI: 10.1021/acsami.7b05365 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX

Research Article

ACS Applied Materials & Interfaces

Figure 1. Schematic illustration of the fabrication process of ordered vertically aligned codoped carbon nanowire arrays from the AAO (anodic aluminum oxide) template with the sputtered gold layer.

Nanoscale devices with specific structures and enhanced performances compared to obsolete macrofunctional devices have received widespread attention. One-dimensional nanostructures applied to the field of supercapacitors may show improved electrochemical properties that can be exploited for fabricating more prominent nanoscale devices because of the small scale and surface-energy effect.12,13 We conveniently and accurately designed the ordered vertically aligned N- and Scodoped carbon nanowire (NS-CNW) array. A large number of high-specific-surface-area vertically aligned nanochannels combined with the synergistic effects of S- and N-codoping in NSCNWs obviously enhanced the ionic conductivity as well as improved the electrochemical properties and cycle stability, which have highly enlightened, and given valuable reference to, the design and manufacture of subtle nanoenergy devices.

■

RESULTS AND DISCUSSION The preparation process of NS-CNWs is shown in Figure 1 (a detailed fabrication process is available in the Experimental Section). The as-prepared NS-CNWs were subsequently inspected by SEM. The cross-sectional image in Figure 2a reveals that the NS-CNWs are vertical to the Au substrate with lengths of about 20 μm (see Figure S1c in the Supporting Information), which is also illustrated in Figure 2c at higher magnification. It is obvious that the highly ordered dense nanowires form large-scale arrays, protruding from the inner surface of the AAO template pores. Additionally, the uniform size distribution of the nanowires with the average diameter of approximately 100−150 nm as shown in the top-view image (Figure 2b) is in agreement with the parameters of the AAO template (Figure S2). In Figure 2d, TEM showed that the diameter of the NS-CNW is also about 100 nm. In the highmagnification TEM image, the dense nanowires were clearly revealed. Additionally, we can see the material object in Figure S3, and the size of the diameter is about 13 mm. Both the N2 adsorption−desorption isotherms and pore size distribution were shown in Figure S4. The specific surface areas (SSAs) of NS-CNWs were calculated to be 403.69 m2 g−1 according to the N2 adsorption−desorption isotherms. Selected area elemental mapping (STEM, yellow boxed area in Figure 2e) was chosen to reveal the compositions in NS-CNWs. As expected, a homogeneous heteroatom distribution of N and S elements in a single nanowire was realized (Figure 2f). The doping of heteroelements into carbon structures can also be analyzed by energy-dispersive X-ray spectrometry (EDS). The NS-CNW sample consists of C, N, S, and O elements on the basis of the EDS spectrum (Figure 3a), in which the N- and S-elemental contents are 4.95 and 2.36 atom %, respectively, as shown in Table S1 (see the Supporting Information). X-ray diffraction (XRD) patterns of the NSCNWs were shown in Figure 3b. According to the character-

Figure 2. (a, c) Cross-sectional SEM images of the NS-CNW array. (b) Top-view SEM image. (d) TEM image of a single NS-CNW (inset, the higher magnification). (e, f) STEM images and C-, N-, S-, and O-elemental mapping of an NS-CNW.

istic peaks at 2θ = 23.95°, the existence of graphitized carbon is attributed to the carbonization process, which is also directly verified by high-resolution TEM without lattice fringes in the inset of Figure 2d. Figure S5 showed the Raman spectra of NSCNWs compared to those of PPy-co-EDOT nanowires. The spectrum of PPy-co-EDOT nanowires indicates typical characteristic absorption peaks of PPy (a series of peaks at ca. 922, 1047, 1238, 1366, and 1410 cm−1)14 and PEDOT (a series of peaks at ca. 694, 860, 984, 1366, and 1410 cm−1),15 suggesting the successful combined polymerization of Py and EDOT. However, after carbonization, only well-documented D (∼1340 cm−1) and G (∼1580 cm−1) bands remain in NSCNWs.16 Moreover, X-ray photoelectron spectroscopy (XPS) was used to study the chemical status of the elements (C, N, and S). The B


Research Article


Figure 4. (a) Model of a symmetric supercapacitor device. (b) CV curves of NS-CNWs at different scan rates in 0.1 M LiClO4. Galvanostatic charge−discharge curves of NS-CNWs at (c) different constant current densities and (d) a current density of 8 A g−1. (e) Triangular shapes of the first, 4 000th, 7 000th, and 10 000th cycles.

Figure 3. (a) EDS spectra for NS-CNWs. (b) XRD patterns of NSCNWs and Au. Chemical binding state of the as-prepared nanowires: (c) XPS survey spectrum of NS-CNWs, S-CNWs, and N-CNWs. The high-resolution spectra of (d) C 1s, (e) N 1s, and (f) S 2p for NSCNWs.

curves, we can observe a good linear relationship between operating potentials and time in the LiClO4 aqueous electrolyte, highlighting a small equivalent series resistance and rapid I−V response to reach ideal capacitive characteristics similarly obtained by the CV curves mentioned above. Moreover, the electrochemical durability of the NS-CNWs can be characterized by the charge−discharge cycles at 8.0 A g−1. The shapes of NS-CNW galvanostatic charge and discharge curves are symmetrical and triangular within the first 20 cycles (Figure 4d), in addition to retaining their nearly original shape after the 4000th and even 10 000th cycle (Figure 4e), proving the sufficient cycle stability of the electrode materials. For a better verification of the superiority of the electrochemical performances of NS-CNWs, controlled trials were carried out. In contrast to the N-CNWs and S-CNWs, the NSCNWs possessed the larger closed area of CV curves at a scan rate of 20 mV s−1 (Figure 5a) and the longer discharging time at a density of 1 A g−1 (Figure 5b), offering a much higher capacitance. The specific capacitance of NS-CNWs is about 243.0 F g−1 at a current density of 0.1 A g−1, significantly better than those of the N-CNWs (192.5 F g−1) and S-CNWs (126.5 F g−1) (Figure 5c). It has been reported that pyrrolic N enhances capacitance mainly because of its pseudocapacitive contributions and the improvement of wettability.25 The graphitic N accelerates electron transfer and decreases the intrinsic resistance of carbon;26 meanwhile, pyridinic N increases the attraction of ions. They all play very good roles in promoting the capacitance value. Not only that, but also the S-doping can modify the surface features of the electrode.27 Therefore, on one hand, the synergistic effects of S- and Ncodoping account for the primary role in the electrochemical performance.16,28−32 On the other hand, the NS-CNWs with

survey scan of NS-CNWs (Figure 3c) showed an elemental composition that is identical to that obtained from EDS. The high-resolution spectra of C 1s in NS-CNWs (Figure 3d) can be deconvoluted into three single peaks, corresponding to C SC (283.9 eV),17 CNC (287.2 eV),18 and CC (284.8 eV), and the peak at about 285.5 eV suggested the presence of CO,19 confirming that N and S heteroatoms have been doped into the carbon structure. Remarkably, the highresolution N 1s spectra of NS-CNWs (Figure 3e) demonstrated the formation of graphitic, pyridinic, and pyrrolic N, which exist similarly in N-doped carbons.11 Then, the S 2p XPS spectra (Figure 3f) showed that the bonding properties of the S atom are CSC (164.05 eV), CS (165.0 eV), CSO (166.0 eV), and CSO2 (168.6 eV).11,20 The electrochemical performances of the NS-CNWs were analyzed by using the technology of cyclic voltammetry (CV) at a potential interval 0−0.8 V. As presented in Figure 4a, a twoelectrode system test is preferred to provide the best indication of the electrochemical performance.21 We also tested the electrochemical performance of the N-CNWs and S-CNWs as comparisons to confirm the essence of the superior performance of the NS-CNW supercapacitor.22−24 Interestingly, the CV profiles maintain quasirectangular shapes with an increasing sweep rate from 10 to 500 mV s−1, exhibiting a typical capacitive behavior (Figure 4b). Additionally, galvanostatic charge and discharge measurements within the same voltage window as that of CV were also executed at various current densities (from 0.5 to 8 A g−1, Figure 4c). More details about the CV and galvanostatic charge and discharge curves of NSCNWs at different constant current densities can be noted in Figure S6a,b. On the basis of the symmetric charge−discharge C


Research Article


retention ratio of NS-CNWs and S-CNWs has exceeded or is very close to 100% which displays good cycling and stability behavior.36 We also calculated the power density and energy density to further evaluate the electrochemical performance. The Ragone plot for the symmetric capacitor in 0.1 M LiClO4 aqueous electrolyte was shown in Figure 5f. NS-CNWs with an energy density of 5.27 W h kg−1 were obtained, while the N-CNWs and S-CNWs showed the values of 4.21 and 2.80 W h kg−1 at 0.1 A g−1. The specific energy density of NS-CNWs can remain 4.31 W h kg−1 at the power density of 1747 W kg−1 when the current density is 8 A g−1. In a word, the dual-heteroatomdoped carbon nanowire performed well concerning electrochemical properties for supercapacitors.

■

CONCLUSION In summary, we have fabricated an ingenious NS-CNW array through the electrochemical codeposition of Py and EDOT as C, N, and S sources coupled with carbonization. The good capacitive performance for NS-CNWs benefits from the novelty of composition and structure. Specifically, the sample exhibits a high electrochemical capacitance (243.0 F g−1 at the current density of 0.1 A g−1), and good cycling stability (10 000 cycles). Results show that the effective method is useful for fabricating multicomponent-doped carbon with a high electrochemical performance. Therefore, the multicomponent-doped CNW arrays have great potential to become a versatile and efficient material for electrochemical supercapacitors. The controlled preparation of ordered vertically aligned codoped carbon nanowire arrays here not only opens up a new opportunity for obtaining the nanostructure with a designed complex component, but also obtains an advanced electrode with highperformance supercapacitors, which will appeal to the development of next-generation low-cost carbon-related electronic and energy devices.

Figure 5. (a) Cyclic voltammograms of NS-CNWs, N-CNWs, and SCNWs at 20 mV s−1. (b) Galvanostatic charge−discharge curves at 1 A g−1. (c) Specific capacitances at different current densities. (d) NSCNW and S-CNW cycling stability of 10 000 cycles at 8 A g−1, and NCNW cycling stability of 5000 cycles at 8 A g−1. (e) Nyquist plots (inset, magnified 0−100 Ω region) and (f) Ragone plots.

abundant permeable channels and fast ion diffusion in electrolyte also retain high capacitance against the variation of current density.33,34 Moreover, we find that the NS-CNWs exhibit higher capacitance compared to other codoped carbon and pure carbon (see Table S2 in the Supporting Information). Figure 5d shows the capacitance retention of CNWs within an electrochemical window ranging from 0 to 0.8 V. Among them, the capacitance retentions of both NS-CNWs and S-CNWs still remain at about 100%, while that of N-CNWs is reduced to 58.37% after 5000 cycles. Electrochemical impedance spectroscopy (EIS) is a primary instrument for the characterization of a supercapacitor’s electrical resistance and for the assessment of its ion transport behavior when the doped carbon nanowire arrays were used as electrode materials (Figure 5e). The diameter of the semicircle in the high-frequency range (18.4 Ω for NS-CNWs, 19.7 Ω for N-CNWs, and 54.1 Ω for S-CNWs) revealed that the charge-transfer resistance (Rct) of NS-CNWs is lowest, which had a favorable effect on the relatively specific power density.35 It is not hard to find that the relatively smaller semicircle of NS-CNWs and N-CNWs can be ascribed to the N-doping which further enhances the capacitance. Nevertheless, the smaller slope of the line in the low-frequency range manifests the slower ion and forms the slower rate of EDLs (electrical double layers), which is not good for the cycling stability of N-doped nanowire electrodes at a higher current density. On the contrary, the larger slope of the line in the lowfrequency range forms the faster rate of EDLs for the S-doping. Meanwhile, the confirmation that ions will be more complete within the S-doped carbon, to intercalate and deintercalate after the initial hundreds of circulations, causes more effective active sites for the NS-CNWs and S-CNWs. The capacitance

■

EXPERIMENTAL SECTION

Materials. EDOT was purchased from Aladdin. AAO templates were bought from Whatman Co., and their main dimensions are as follows: a thickness of 60 μm, a diameter of 13 mm, and an interior porous diameter of 100 nm. The synthesis device of CNWs is a homemade electrolytic cell. Other chemicals (Beijing Chemical Reagent Co. Ltd.) were ready to use without modification. Preparation of Supercapacitors and Electrochemical Measurement. For symmetric supercapacitors, the cathode and anode adopt identical electrode materials. In this work, the original and round samples based on the AAO template can be directly cut by a blade to possess the same size of 2.0 × 2.0 mm2 as electrodes, a filter paper as separator, and two Au plates as current collectors to be measured in 0.1 M LiClO4 aqueous solution. The following equation was applied to calculate the relevant mass of the active sample:

m=

S(m2 − m1) πr 2

(1)

where m is the mass of active sample in one electrode, m1 is the mass of the empty AAO template with sputtered Au, m2 is the mass of the whole sample after the annealing process, r is the radius of the nanowire circular growing area in the AAO template, and S represents the actual area of electrode materials after the cutting treatment by a blade. The graphical calculation of the electrode materials is shown in Figure S7 in the Supporting Information. The calculated mass of the overall round CNWs is 0.5 mg before the cutting treatment, which is consistent with the thermogravimetric analysis (TGA) as shown in Figure S8 (see the Supporting Information). Therefore, the mass of each electrode was calculated D


Research Article


Cu Κα irradiation (k = 1.54 Å). Thermogravimetric analysis (TGA) was obtained by using a thermo balance (TGA 2050) from room temperature to 800 °C at a rate of 10 °C min−1 under a continuous air atmosphere. The specific surface areas (SSAs) were determined by nitrogen adsorption−desorption isotherm measurements at 77 K (NOVA 2200e).

as 0.02 mg on the basis of eq 1. Electrochemical characterizations consisting of cyclic voltammetry (CV), galvanostatic charge− discharge, and electrochemical impedance spectroscopy (EIS) can be measured on the CHI660D electrochemical workstation. The potential of CV and galvanostatic charge−discharge measurements range from 0 to 0.8 V. EIS was recorded in the frequency range 0.1−100 000 Hz under the open-circuit potential. On the basis of the galvanostatic charge−discharge measurement,37−40 the calculation equation of the specific capacitances is C=2

I Δt mΔV

■

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsami.7b05365. Characterizations, N2 adsorption−desorption isotherms, pore size distribution, Raman spectra, CV and galvanostatic charge−discharge curves, graphical calculations, and TGA (PDF)

(2)

Correspondingly, I is the constant discharge current, Δt is the discharging time, m is the mass of active sample within one electrode, and ΔV is the voltage drop upon discharging (excluding the IR drop). The energy density (E) and power density (P) of the full supercapacitors could be calculated in accordance with the following equations:41−46 CV 2 E= 8

(3)

E P= t

(4)

■

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. Phone: 86-10-81381350 (N.C.). *E-mail: [email protected]. Phone: 86-10-68918608 (L.Q.). ORCID

where V is obtained from the discharge curve subtracted by the IR drop, and t is the discharging time.

■

ASSOCIATED CONTENT

S Supporting Information *

Nan Chen: 0000-0002-3105-4509 Notes

SYNTHESIS AND CHARACTERIZATION

The authors declare no competing financial interest.

■

Syntheses of NS-CNW, N-CNW, and S-CNW Arrays. Before electropolymerization, the conducting layer can be obtained by sputtering a layer of Au of about 1 μm thickness in the side of the AAO template in Figure S1a. The specific three-electrode test system is as follows: the working electrode, reference electrode, and counter electrode correspond to the AAO template, a silver/silver chloride electrode, and a platinum (Pt) foil, respectively. As shown in Figure 1, PPy-co-EDOT nanowires can be deposited onto the AAO template by cyclic voltammetry (CV) at a scan rate of 500 mV s−1 in a chromatographically pure acetonitrile solution containing 0.1 M LiClO4, 0.01 M pyrrole, and 0.09 M EDOT. Electrochemical deposition occurred in an electrochemical cell (20 mL volume) at a temperature of about 0−3 °C. The potential window of CV is 0−1.6 V. Making sure Q (electric quantity transferred) is constant, here we control the value between 1.830 and 1.840 C in every deposition. The contrast sample PPy nanowires and PEDOT nanowires were prepared, respectively, in pyrrole and EDOT with the same concentration of 0.1 M. Other experimental conditions are also kept the same as above. The obtained samples were eluted with deionized water several times. Then, the quartz boat carrying the above samples was annealed at 700 °C for 2 h at a heating rate of 5 °C min−1 under argon atmosphere; as a result, PPy-co-EDOT nanowires, PPy nanowires, and PEDOT nanowires were transformed into NS-CNWs, N-CNWs, and S-CNWs, respectively, after which the HF aqueous solution (1:1 in volume) was adopted to remove the AAO template. After being washed by deionized water, the dried samples were obtained. All the samples were held in a sealed and dry environment before characterization and measurement. Characterizations. The morphology of the samples was characterized using the SEM microscope (JSM-7500F) and FET TECNAI F30 high-resolution transmission electron microscope (HRTEM). The scanning transmission electron microscopy (STEM) instrument was explored for the performance of elemental mappings with a high-angle annular dark-field (HAADF) detector (HITACHI S5500) operating at 30 kV. Raman spectra were recorded using an RM 2000 microscopic confocal Raman spectrometer (Renishaw PLC, England) with a 633 nm laser. X-ray photoelectron spectroscopy (XPS) data were collected on an ESCALab220i-XL electron spectrometer from VG Scientific using 300 W Al Κα radiation. Xray diffraction (XRD) patterns were obtained by using a PW-1710 (Philips, Netherlands) diffractometer with graphite monochromatized

ACKNOWLEDGMENTS This work was sponsored by NSFC (Grants 21671020, 21325415, and 21301018) and Beijing Natural Science Foundation (2172049 and 2152028).

■

REFERENCES

(1) Liu, C.; Li, F.; Ma, L. P.; Cheng, H. M. Advanced Materials for Energy Storage. Adv. Mater. 2010, 22, E28−E62. (2) Simon, P.; Gogotsi, Y. Materials for Electrochemical Capacitors. Nat. Mater. 2008, 7, 845−854. (3) Wang, G.; Zhang, L.; Zhang, J. A Review of Electrode Materials for Electrochemical Supercapacitors. Chem. Soc. Rev. 2012, 41, 797− 828. (4) Aricò, A. S.; Bruce, P.; Scrosati, B.; Tarascon, J. M.; Van Schalkwijk, W. Nanostructured Materials for Advanced Energy Conversion and Storage Devices. Nat. Mater. 2005, 4, 366−377. (5) Dai, L.; Chang, D. W.; Baek, J. B.; Lu, W. Carbon Nanomaterials for Advanced Energy Conversion and Storage. Small 2012, 8, 1130− 1166. (6) Shi, Y.; Peng, L.; Ding, Y.; Zhao, Y.; Yu, G. Nanostructured Conductive Polymers for Advanced Energy Storage. Chem. Soc. Rev. 2015, 44, 6684−6696. (7) Li, Y.; Zhao, Y.; Cheng, H.; Hu, Y.; Shi, G.; Dai, L.; Qu, L. Nitrogen-doped Graphene Quantum Dots With Oxygen-rich Functional Groups. J. Am. Chem. Soc. 2012, 134, 15−18. (8) Zhao, Y.; Hu, C.; Hu, Y.; Cheng, H.; Shi, G.; Qu, L. A versatile, Ultralight, Nitrogen-doped Graphene Framework. Angew. Chem. 2012, 124, 11533−11537. (9) Wu, Z. S.; Winter, A.; Chen, L.; Sun, Y.; Turchanin, A.; Feng, X.; Müllen, K. Three-dimensional Nitrogen and Boron Co-doped Graphene for High-performance All-solid-state Supercapacitors. Adv. Mater. 2012, 24, 5130−5135. (10) Chen, L. F.; Huang, Z. H.; Liang, H. W.; Gao, H. L.; Yu, S. H. Three-dimensional Heteroatom-doped Carbon Nanofiber Networks Derived from Bacterial Cellulose for Supercapacitors. Adv. Funct. Mater. 2014, 24, 5104−5111. (11) Liang, J.; Jiao, Y.; Jaroniec, M.; Qiao, S. Z. Sulfur and Nitrogen Dual-doped Mesoporous Graphene Electrocatalyst for Oxygen E


Research Article

ACS Applied Materials & Interfaces Reduction with Synergistically Enhanced Performance. Angew. Chem., Int. Ed. 2012, 51, 11496−11500. (12) Gao, M.; Huang, S.; Dai, L.; Wallace, G.; Gao, R.; Wang, Z. Aligned Coaxial Nanowires of Carbon Nanotubes Sheathed With Conducting Polymers. Angew. Chem., Int. Ed. 2000, 39, 3664−3667. (13) Chen, Z.; Yu, D.; Xiong, W.; Liu, P.; Liu, Y.; Dai, L. Graphenebased Nanowire Supercapacitors. Langmuir 2014, 30, 3567−3571. (14) Zhao, L.; Fan, L. Z.; Zhou, M. Q.; Guan, H.; Qiao, S.; Antonietti, M.; Titirici, M. M. Nitrogen-containing Hydrothermal Carbons with Superior Performance in Supercapacitors. Adv. Mater. 2010, 22, 5202−5206. (15) Wu, D.; Zhang, J.; Dong, W.; Chen, H.; Huang, X.; Sun, B.; Chen, L. Temperature Dependent Conductivity of Vapor-phase Polymerized PEDOT Films. Synth. Met. 2013, 176, 86−91. (16) Ito, Y.; Cong, W.; Fujita, T.; Tang, Z.; Chen, M. High Catalytic Activity of Nitrogen and Sulfur Co-doped Nanoporous Graphene in the Hydrogen Evolution Reaction. Angew. Chem., Int. Ed. 2015, 54, 2131−2136. (17) Wan, S.; Wang, L.; Xue, Q. Electrochemical Deposition of Sulfur Doped DLC Nanocomposite Film at Atmospheric Pressure. Electrochem. Commun. 2010, 12, 61−65. (18) Zheng, Y.; Jiao, Y.; Chen, J.; Liu, J.; Liang, J.; Du, A.; Zhang, W.; Zhu, Z.; Smith, S. C.; Jaroniec, M.; et al. Nanoporous GraphiticC3N4@Carbon Metal-free Electrocatalysts for Highly Efficient Oxygen Reduction. J. Am. Chem. Soc. 2011, 133, 20116−20119. (19) Dong, Y.; Pang, H.; Yang, H. B.; Guo, C.; Shao, J.; Chi, Y.; Li, C. M.; Yu, T. Carbon-based Dots Co-doped with Nitrogen and Sulfur for High Quantum Yield and Excitation-Independent Emission. Angew. Chem., Int. Ed. 2013, 52, 7800−7804. (20) Li, Y.; Zhang, H.; Wang, Y.; Liu, P.; Yang, H.; Yao, X.; Wang, D.; Tang, Z.; Zhao, H. A Self-Sponsored Doping Approach for Controllable Synthesis of S and N Co-doped Trimodal-porous Structured Graphitic Carbon Electrocatalysts. Energy Environ. Sci. 2014, 7, 3720−3726. (21) Stoller, M. D.; Ruoff, R. S. Best Practice Methods for Determining an Electrode Material’s Performance for Ultracapacitors. Energy Environ. Sci. 2010, 3, 1294−1301. (22) Huang, Y.; Zhu, M.; Huang, Y.; Li, H.; Pei, Z.; Xue, Q.; Liao, Z.; Wang, Z.; Zhi, C. A Modularization Approach for Linear-shaped Functional Supercapacitors. J. Mater. Chem. A 2016, 4, 4580−4586. (23) Huang, Y.; Zhu, M.; Pei, Z.; Xue, Q.; Huang, Y.; Zhi, C. A Shape Memory Supercapacitor and Its Application in Smart Energy Storage Textiles. J. Mater. Chem. A 2016, 4, 1290−1297. (24) Meng, C.; Liu, C.; Chen, L.; Hu, C.; Fan, S. Highly Flexible and All-solid-state Paperlike Polymer Supercapacitors. Nano Lett. 2010, 10, 4025−4031. (25) Kwon, T.; Nishihara, H.; Itoi, H.; Yang, Q.-H.; Kyotani, T. Enhancement Mechanism of Electrochemical Capacitance in Nitrogen-/Boron-doped Carbons with Uniform Straight Nanochannels. Langmuir 2009, 25, 11961−11968. (26) Hulicova-Jurcakova, D.; Seredych, M.; Lu, G. Q.; Bandosz, T. J. Combined Effect of Nitrogen- and Oxygen-containing Functional Groups of Microporous Activated Carbon on Its Electrochemical Performance in Supercapacitors. Adv. Funct. Mater. 2009, 19, 438− 447. (27) Zhao, X.; Zhang, Q.; Chen, C.-M.; Zhang, B.; Reiche, S.; Wang, A.; Zhang, T.; Schlögl, R.; Su, D. S. Aromatic Sulfide, Sulfoxide, and Sulfone Mediated Mesoporous Carbon Monolith for Use in Supercapacitor. Nano Energy 2012, 1, 624−630. (28) Duan, X.; O’Donnell, K.; Sun, H.; Wang, Y.; Wang, S. Sulfur and Nitrogen Co-doped Graphene for Metal-free Catalytic Oxidation Reactions. Small 2015, 11, 3036−3044. (29) Zhang, H.; Liu, X.; He, G.; Zhang, X.; Bao, S.; Hu, W. Bioinspired Synthesis of Nitrogen/Sulfur Co-doped Graphene as An Efficient Electrocatalyst for Oxygen Reduction Reaction. J. Power Sources 2015, 279, 252−258. (30) Dong, L.; Hu, C.; Huang, X.; Chen, N.; Qu, L. One-Pot Synthesis of Nitrogen and Phosphorus Co-doped Graphene and Its

Use as High-performance Electrocatalyst for Oxygen Reduction Reaction. Chem. - Asian J. 2015, 10, 2609−2614. (31) Dong, L.; Hu, C.; Song, L.; Huang, X.; Chen, N.; Qu, L. A Large-area, Flexible, and Flame-retardant Graphene Paper. Adv. Funct. Mater. 2016, 26, 1470−1476. (32) Hu, C.; Xue, J.; Dong, L.; Jiang, Y.; Wang, X.; Qu, L.; Dai, L. Scalable Preparation of Multifunctional Fire-retardant Ultralight Graphene Foams. ACS Nano 2016, 10, 1325−1332. (33) Chen, L. F.; Huang, Z. H.; Liang, H. W.; Guan, Q. F.; Yu, S. H. Bacterial-cellulose-derived Carbon Nanofiber@MnO2 and Nitrogendoped Carbon Nanofiber Electrode Materials: An Asymmetric Supercapacitor with High Energy and Power Density. Adv. Mater. 2013, 25, 4746−4752. (34) Hao, L.; Li, X.; Zhi, L. Carbonaceous electrode materials for supercapacitors. Adv. Mater. 2013, 25, 3899−3904. (35) Luo, W.; Wang, B.; Heron, C. G.; Allen, M. J.; Morre, J.; Maier, C. S.; Stickle, W. F.; Ji, X. Pyrolysis of Cellulose Under Ammonia Leads to Nitrogen-doped Nanoporous Carbon Generated Through Methane Formation. Nano Lett. 2014, 14, 2225−2229. (36) Yan, X.; Liu, Y.; Fan, X.; Jia, X.; Yu, Y.; Yang, X. Nitrogen/ Phosphorus Co-doped Nonporous Carbon Nanofibers for Highperformance Supercapacitors. J. Power Sources 2014, 248, 745−751. (37) Zhang, L.; Shi, G. Preparation of Highly Conductive Graphene Hydrogels for Fabricating Supercapacitors with High Rate Capability. J. Phys. Chem. C 2011, 115, 17206−17212. (38) Yu, C.; Masarapu, C.; Rong, J.; Wei, B.; Jiang, H. Stretchable Supercapacitors Based on Buckled Single-walled Carbon-nanotube Macrofilms. Adv. Mater. 2009, 21, 4793−4797. (39) Yan, Y.; Cheng, Q.; Wang, G.; Li, C. Growth of Polyaniline Nanowhiskers on Mesoporous Carbon for Supercapacitor Application. J. Power Sources 2011, 196, 7835−7840. (40) Wang, K. P.; Teng, H. The Performance of Electric Double Layer Capacitors Using Particulate Porous Carbons Derived from PAN Fiber and Phenol-formaldehyde Resin. Carbon 2006, 44, 3218− 3225. (41) Xia, X.; Zhang, Y.; Chao, D.; Xiong, Q.; Fan, Z.; Tong, X.; Tu, J.; Zhang, H.; Fan, H. J. Tubular TiC Fiber Nanostructures as Supercapacitor Electrode Materials with Stable Cycling Life and Widetemperature Performance. Energy Environ. Sci. 2015, 8, 1559−1568. (42) An, N.; An, Y.; Hu, Z.; Guo, B.; Yang, Y.; Lei, Z. Graphene Hydrogels Non-covalently Functionalized with Alizarin: An Ideal Electrode Material for Symmetric Supercapacitors. J. Mater. Chem. A 2015, 3, 22239−22246. (43) Xu, Y. X.; Lin, Z. Y.; Zhong, X.; Huang, X. Q.; Weiss, N. O.; Huang, Y.; Duan, X. F. Holey Graphene Frameworks for Highly Efficient Capacitive Energy Storage. Nat. Commun. 2014, 5, 4554. (44) Chen, L. F.; Huang, Z. H.; Liang, H. W.; Gao, H. L.; Yu, S. H. Three-dimensional Heteroatom-doped Carbon Nanofiber Networks Derived from Bacterial Cellulose for Supercapacitors. Adv. Funct. Mater. 2014, 24, 5104−5111. (45) Chen, Z.; Augustyn, V.; Wen, J.; Zhang, Y.; Shen, M.; Dunn, B.; Lu, Y. High-performance Supercapacitors Based on Intertwined CNT/ V2O5 Nanowire Nanocomposites. Adv. Mater. 2011, 23, 791−795. (46) Chen, Z.; Wen, J.; Yan, C.; Rice, L.; Sohn, H.; Shen, M.; Cai, M.; Dunn, B.; Lu, Y. High-performance Supercapacitors Based on Hierarchically Porous Graphite Particles. Adv. Energy Mater. 2011, 1, 551−556.

F


Built Structure of Ordered Vertically Aligned Codoped Carbon

Recommend Documents