Template-Free, Self-Doped Approach to Porous Carbon Spheres with

Subscriber access provided by LUNDS UNIV

Article

A Template-Free, Self-Doped Approach to Porous Carbon Spheres with High N/O Contents for High-Performance Supercapacitors Danfeng Xue, Dazhang Zhu, Wei Xiong, Tongcheng Cao, Zhiwei Wang, Yaokang Lv, Liangchun Li, Mingxian Liu, and Lihua Gan ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.8b06774 • Publication Date (Web): 04 Mar 2019 Downloaded from http://pubs.acs.org on March 7, 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 32 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 Sustainable Chemistry & Engineering

A Template-Free, Self-Doped Approach to Porous Carbon Spheres with High N/O Contents for High-Performance Supercapacitors Danfeng Xue,† Dazhang Zhu,† Wei Xiong,‡ Tongcheng Cao,†, ⊥ Zhiwei Wang,§ Yaokang Lv,¶ Liangchun Li,† Mingxian Liu,*,†,§ Lihua Gan*,†

†Shanghai

Key Lab of Chemical Assessment and Sustainability, School of Chemical Science and

Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China. ‡Key

Laboratory for Green Chemical Process Ministry of Education, School of Chemistry and

Environmental Engineering, Wuhan Institute of Technology, 693 Xiongchu Road, Wuhan 430073, P. R. China. §State

Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution

Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China. ¶College

of Chemical Engineering, Zhejiang University of Technology, 18 Chaowang Road,

Hangzhou 310014, P. R. China. ⊥ Key

Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University,

4800 Caoan Road, Shanghai 201804, P. R. China.

*Corresponding Authors. E-mail: [email protected] (M. Liu), [email protected] (L. Gan)

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 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: A template-free and self-doping approach is developed for fabricating N, Oenriched porous carbon spheres (PCSs) via direct carbonization/activation of melamine-glyoxal polymer. Interconnected spherical morphology of PCSs generates stacking porosities as ion reservoirs for rapid ion diffusion and affords conductive networks to shorten the transport lengths for electron transfer. Besides, PCSs exhibit a large surface area (1302 m2 g−1), ample ultramicropores (0.54 nm), and developed supermicro- and mesopores. This unique pore architecture provides optimized ion-accessible pore size to enhance double layer capacitance, and serves as ion-highways for rapid diffusion of electrolyte ions. Furthermore, high N/O elements (7.97/10.16 wt.%) incorporated into PCSs improve surface wettability, and supply additional pseudocapacitance. Therefore, the resultant PCS electrodes exhibit superior electrochemical performances, such as a high specific capacitance up to 344 F g−1 at 1.0 A g−1, remarkable rate capability and long-term stability in a three-electrode. Notably, PCS-based supercapacitor exhibits an impressive energy density of 33.37 Wh kg−1 and power density of 9000 W kg−1 in Na2SO4 electrolyte. This result provides a simple and efficient fabrication of PCSs for high-performance supercapacitors. KEYWORDS: Self-templating; Self-doping; Porous carbon spheres; High N/O contents; Supercapacitor.


Page 2 of 32

Page 3 of 32 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


INTRODUCTION Carbon-based supercapacitors, also called electrical double layer capacitors (EDLCs), have attracted considerable research interest as advanced power-type energy storage devices because of their unique properties, including high power density, long cycle life and rapid charging/discharging rate as well as high safety.1-6 Various carbons such as carbide derived carbon,7 carbon onion,8 ordered mesoporous carbon,9 carbon aerogels,10 and carbon nanotube11 have been employed as electrode materials and shown excellent capacitive behaviors. EDLCs store energy through the reversible adsorption of interfacial electrolyte ions, and the ion accessible surface area of carbon electrode materials thus is pivotal to determine the electrochemical performance.12-14 Besides, the capacitive performance are also drastically influenced by the pore size together with its distribution and the morphologies of carbon materials which largely affect accessible surface area, ion transport distance and resistance.15-17 Micropores enhance the electrical double layer, and mesopores provide ion-transport highways to reduce the resistance. While macropores can act as ion-buffering reservoirs to effectively shorten ion transport distance into electrochemical active surface. Usually, hierarchical pore structure comprised of micro-, meso-, and/or macropores takes the merits of each pore size via a synergistic action during the electrochemical charging/discharging process.18-19 On the other hand, among various carbons, carbon spheres integrate the advantages of carbon materials with spherical colloids, which gives them several unique features involving uniform morphology, good liquidity, high surface-tovolume ratios, tunable porosity and controllable particle size, which show important prospects in catalytic supports, gas separation/storage as well as energy storage and conversion.20-23 In order to construct fine pore structure and particular geometry for carbons, an efficient but sophisticated template method is usually employed,24-26 in which porosity is originated from hard ACS Paragon Plus Environment


or soft sacrificial component and established architecture is obtained simultaneously. Although this approach can realize the control of morphology and well-defined porous structure, it usually suffers from complicated synthesis,12, 23, 27 involving template synthesis, infiltration of the precursor onto the template, cross-linking and carbonization process (usually accompanied with activation), and template removal. Consequently, the multi-steps, time-consuming procedures, expensive templates along with toxic or corrosive reagents have largely limited their application potentials. Templatefree methods thus have been put forward to overcome these disadvantages, which are more attractive and alternative for fabricating well-designed carbons. For example, honeycomb-like porous carbon flakes with developed porosity were fabricated from the maize via microwave puffing, pre-carbonization and post-activation.28 Micro-, meso-, and macroporous carbon nanotube sponges were constructed through a controllable, binder and self-assembly of superaligned carbon nanotubes using low pressure chemical vapor deposition and a freeze-drying process.29 These approaches achieve the controllable synthesis of diverse carbons, but also have some shortages such as tedious operations or complicated techniques, etc. Thus, it is still desirable to develop efficient self-templated routes to prepare porous carbons with reasonable pore architecture and well-designed geometry. In addition to tailoring the properties of pure carbons, an effective way to further improve the capacitive performances is heteroatom (e.g., N, S, O, and P atoms) doping.30-31 The introduction of heteroatoms into carbon framework is capable of enhancing the surface wettability with electrolytes to optimize the accessible surface.32-33 For example, Qiu et al. fabricated N-doped carbon layer as a superhydrophilic “nanoglue” to form a superhydrophilic surface/interface, which stabilize metal hydroxides onto carbons for fabricating high performance hybrid electrodes.34 Meanwhile, the functional atoms could deliver additional pseudo-capacitance originated from fast ACS Paragon Plus Environment

Page 4 of 32

Page 5 of 32 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


and reversible Faradaic reactions.35-36 Functionalized carbons can be generally fabricated by in-situ carbonization of heteroatom-riched carbon sources, or posttreatment of carbons in certain chemical environment (ammonia, H2SO4, atmosphere, H3PO4, etc.).37 The post-synthesized modification usually faces the demerits of morphology defect, pore blockage or collapse, while the self-doped approach exhibits the merits of controllable dopants, immobile pore structure, and evenly distributed heteroatoms, which shows important prospects for synthesis of heteroatom-doped carbon-based materials. For example, Ni et al. fabricated N-doped carbon foams (5.34 wt.%) with nanographitic domains via transition metal acetate assisted self-N-doping method, which had a reversible capacity of 273 F g−1 at 0.5 A g−1 as a supercapacitor electrode.38 Using N-riched diamino-anthraquinone

as

a

linker

to

connect

the

rigid

polyquinoneimine

with

perylenetetracarboxylic dianhydride, Zhou et al. designed N, O self-doped porous carbons for supercapacitor electrodes (125  F g−1 at 10 A g−1).39 Self-doped approach in favor of homogeneous distribution of the entrapped heteroatoms in the carbon matrix, but usually suffers a relatively low dopant (e.g., PCS750 > CS800 > PCS850. PCS800 electrode holds quasi-rectangular shaped curve as the scan rate increases to 100 mV s−1 (Figure 7b), exhibiting remarkable rate capability. GCD profiles of CS800 and PCS electrodes at 1.0 A g−1 displayed in Figure 7c show quasi-symmetrical triangular shapes. CS800 electrode, despite having low surface area (578 m2 g−1), displays a high capacitance of 232 F g−1 at 1.0 A g−1 which is similar with that of PCS750 electrode (250 F g−1) and larger than that of PCS850 electrode (106 F g−1), because its ample ultramicropores afford optimized ionaccessible pore size to reinforce double layer capacitance49 and high N/O contents to offer up


Page 15 of 32 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


pseudo-capacitance. The capacitive contribution comes from the surface area accountable for electrical double layer capacitance and N/O dopants responsible for pseudocapacitance. Although three PCS samples show similar heteroatom contents of 18.79−17.12 wt.%, PCS800 has higher N5 and N-6 species, together with much higher surface area, and thus exhibits a supreme capacitance of 344 F g−1 at 1.0 A g−1. Besides, at a high current density of 20 A g−1, PCS800 electrode keeps a capacitance of 210 F g−1 (Figures 7d and e), suggesting KOH electrolyte ions can easily transport and diffuse into the pore channels of the electrode under fast charging/discharging operation. Figure 7f shows the capacitance and cycle performance of PCS800 electrode at different current densities within ten cycles. With increasing current densities from 1 to 20 A g−1, the capacitances gradually decline. While the electrode capacitances change to the initial values afterwards, indicating an excellent electrochemical recoverability. To better understand the capacitive contributions, the total capacitance (CT) of electrode was divided into electric double layer capacitance (CE) from active surface area and pseudocapacitance (CP) from the redox couples of N/O functional groups. Figure 7g provides the relationships of CT versus square root of discharge time. Generally, CT contains a rate-independent component kl (ordinate intercept of the curves, related to CE) and a diffusion-limited component, k2t1/2 (relevant to pseudocapacitance), the equation as follows:14 CT = kl + k2t1/2 Equation 1 The related capacitance values (CT, CE and Cm) are provided in Table 2. The CE values are proportional to the surface areas in a sense due to the EDLC mechanism. Among all prepared electrodes, PCS800 shows the highest CE of 208 F g−1 due to the largest surface area. Introduction of electrochemically active N/O atoms into carbon matrix could effectively enhance the capacitance through yielding additional CP. CS800 exhibits the highest CP of 162 F g−1 resulted ACS Paragon Plus Environment


Page 16 of 32

from the highest heteroatoms contents (N+O, 21.95 wt.%). PCS800 delivers a CP contribution of 136 F g−1, although it shows relatively lower heteroatoms dopants (18.13 wt.%) than that of PCS750 (18.7 wt.%), which can be assigned to the more effective N-5 and N-6 species. In addition, PCS800 electrode presents an outstanding stability with 93.8% retention after consecutive 10000 cycles (Figure 7h) at 5.0 A g−1, accompanied with a high coulomb efficiency of 97.8%, attributed to a prominent ion/electron-transfer process during the long-term circulation.

Figure 7. CV curves of CS800 and PCSs electrodes at 50 mV s−1 (a) and PCS800 electrode at various scan rates (b), GCD curves of CS800 and PCSs electrodes at 1.0 A g−1 (c) and PCS800 electrode at various current densities (d), capacitances vs. current densities of the carbon-based electrodes (e), rate performance of PCS800 electrode (f), capacity vs. square root of half-cycle time (g), cycling stability of PCS800 electrode at 5.0 A g−1 (h) in KOH electrolyte. ACS Paragon Plus Environment

Page 17 of 32 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


Nyquist plots of CS and PCS electrodes are given in Figure S4. The nearly vertical lines at the low frequency region indicate an ideal capacitive behavior without diffusion limitation; meanwhile, the about 45° diagonal lines manifest excellent pore accessibility for the electrolyte ions.61 The intercept with the Z' axis indicates the equivalent series resistance (Rs, consisting of electrode resistance, contact resistance at the electrode/electrolyte interface, and the electrolyte ionic resistance inside the pore channels).62 The capacitor circuit model comprises Rs, the charge transfer resistance (Rct, represented by the semicircle shape) and the constant phase angle element (CPE).63 All these sample electrodes have very low Rs values (< 0.5 Ω), which demonstrates rapid charge diffusion and outstanding conductivity.42 Packing cavities as ion buffer reservoirs benefit the improvement of ion transport kinetics by shortening diffusion distance. Interconnected spherical morphology provides conductive network to decrease the electric resistance. PCS800 shows the lowest Rs value of 0.27 Ω among the sample electrodes (0.29 and 0.35 Ω for PCS750 and PCS800, and 0.48 Ω for CS800), due to much higher surface area and more developed supermicropores and mesopores to serve as ion-highways for fast ion transfer. PCS800 is an optimized sample with superior electrochemical performance. Based on this, we further conducted different KOH/polymer ratio during activation process to study the transmutation of the porosity, heteroatoms dopants, and capacitance behaviors of PCSx (x denotes the KOH/polymer ratios, w/w). With the ratios increasing from 0.5:1 to 1.5:1, the mesopores in PCSs become developed (Figure S5) due to the reaction between carbons and KOH, while PCS1.0 possesses higher surface areas of 1302 m2 g−1 than those of PCS0.5 (657 m2 g−1) and PCS1.5 (768 m2 g−1). Correspondingly, the N dopants reduce from 9.11 to 2.45 wt.% (Figure S5 and Table S2). PCS800 (activated with ratio of 1:1) is optimal in terms of porosity structure and N/O contents to achieve the best electrochemical performance (Figure S6). ACS Paragon Plus Environment


Page 18 of 32

PCS800 was assembled into a symmetric supercapacitor using KOH electrolyte under a potential range of 0−1 V. As depicted in Figures 8a and b, all the CV profiles display quasi-rectangular shapes under 100 mV s−1, GCD curves show good symmetrical triangle at high loading current density of 10 A g−1, revealing remarkable electrochemical behaviors of PCS800-based symmetrical supercapacitor. The gravimetric capacitance of PCS800 electrode in two-electrode device is 267 F g−1 at 0.5 A g−1, and remains 147 F g−1 at 10 A g−1. The coulomb efficiency obtained at low current density (0.5 A g−1) is 94.2% because in the charge process, the charge repulsion is going stronger due to the gradually increasing amount of charges, especially under the condition when the storage space of the electrode is near saturation, resulting to the extended charge time. Under a large current density of 10 A g−1, owing to the sufficient charges the coulomb efficiency reaches an ultrahigh value of 99.1%. The Ragone plots (Figure 8c) of the PCS800//PCS800 symmetric device delivers an energy density of 9.23 Wh kg−1 at the power density of 400 W kg−1 under 0.5 A g−1. When the current density increases to 10 A g−1, the power density is 5000 W kg−1. PCS800-based supercapacitors using KOH-electrolyte shows advantages over many reported carbon-based devices given in Table S3.

Figure 8. PCS800 electrode electrochemical performance in a two-electrode system using 6 M KOH electrolyte. CV curves at various scan rates (a), GCD curves at different current densities (b), and Ragone plots of PCS800 (c).


Page 19 of 32 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


According to the calculation equation of energy density (E=0.5CV2) , the energy density is not only related to electrode capacitance, but also closely inherited from the operating voltage. PCS800 possesses a high capacitance in KOH solution than those of recently-reported carbon-based electrodes , but the energy density is still low due to the limited voltage window of 1 V. Neutral Na2SO4 electrolyte with a higher pontential window (1.8 V) can further enhance the energy density of supercapacitor device. Figure 9a exhibits CV curves of the assembled PCS800//PCS800 symmetric device using Na2SO4 electrolyte in various voltage windows at 10 mV s−1. The CV curves keep rectangular-like shape and no obvious distortion even the potential range enlarged to 1.8 V. Besides, the curve still holds a well rectangular shape at 100 mV s−1 (Figure 9b), indicating remarkable rate performance. GCD curves of the device shown in Figure 9c exhibit nearly symmetric-triangle and low IR drops, indicating low internal series resistance and outstanding charging/discharging reversibility. The capacitance of the device reaches 74.2 F g−1 at 0.5 A g−1, and maintains 40 F g−1 at a high current density of 10 A g−1 (Figure 9d). The rate performance shown in Figure 9e reveals high invariability. The symmetric supercapacitor exhibits a high cycling stability with 94.3% retention over 10000 cycles at 2.0 A g−1 (Figure 9f), accompanied with a high coulomb efficiency of 98%. Moreover, as displayed in Ragone plots (Figure 9g), the device delivers a high energy density of 33.37 Wh kg−1 at power density of 450 W kg−1 (0.5 A g−1) still maintains 15 Wh kg−1 at the power density of 9000 W kg−1 (10 A g−1), superior to commercially available carbon-based supercapacitors (< 6 W h kg−1),64 and most recently-reported neutral-electrolyte symmetric supercapacitors based on PCF-700 (13.9 Wh kg−1, 460 W kg−1),59 WJC-800 (18.6 Wh kg−1, 400 W kg−1),65 G/CNTs-200 (8 Wh kg−1, 900 W kg−1),66 IPC2-0.2-8 (21.9 Wh kg−1, 461 W kg−1),67 BNDC (14.1 Wh kg−1, 2000 W kg−1),68 HPCs (14.2 Wh kg−1, 444.5 W kg−1),61 and PCACM (10.42 Wh kg−1, 8928 W kg−1).69 A detailed comparison of this work with reported neutral-electrolyte ACS Paragon Plus Environment


Page 20 of 32

supercapacitors is shown in Table S4. Profiting from spherical morphology, large surface area with well-defined pore architecture (ultramicro, supermicro, and mesopores), abundant N/O dopants of the carbon-based electrode, and the high operation voltage of Na2SO4 electrolyte, the PCS800 assembled supercapacitor exhibits impressive electrochemical behaviors, including high energy density without the loss of power density, and superior long-term cycling stability.

Figure 9. Electrochemical performances of PCS800-based symmetric supercapacitor using Na2SO4 solution: (a) CV curves in various potential windows at a scan rate of 10 mV s−1, (b) CV curves at different scan rates, (c) GCD curves at various current densities, specific capacitances at various current densities (d), rate performance of device (e), cycling stability and coulombic efficiency at 2.0 A g−1 over 10000 cycles (f), Ragone plots of the device and recently reported carbon-based supercapacitors (g). ACS Paragon Plus Environment

Page 21 of 32 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


CONCLUSION In conclusion, we demonstrate a simple and template-free approach to fabricate heteroatomdoped PCSs through polymerization of melamine/glyoxal and one-step carbonization/activation process. As-prepared PCSs combine four characteristics of interconnected spherical geometry (~700 nm), high surface area (up to 1302 m2 g−1), hierarchically porous structure (ultramicro-, supermicro- and mesopore), and high-level N/O dopants (7.97 and 10.16 wt.%). The fused carbon particles can minimize ion diffusion lengths, and serve as charge carriers and conductive network for enhancing the ion/electron transfer efficiency. Whereas unique pore architecture simultaneously offers high-density active sites to accumulate charges for maximizing double-layer capacitance, and supplies speedy transport paths to support capacitance and rate capability. Moreover, N/O functional groups could significantly improve the electrochemical properties by triggering pseudocapacitance and optimizing the electrode surface wettability. These distinct features afford superior electrochemical behaviours including high capacitance of 344 F g−1 at 1.0 A g−1 and high-rate performance together with excellent long-term cycle stability in a threeelectrode system. Furthermore, PCS electrode delivers high energy density of 33.37 Wh kg−1 at a power density of 450 W kg−1 and remains 15 Wh kg−1 at a high power of 9000 W kg−1 in Na2SO4 electrolyte. Therefore, this study holds a great promise for facile and efficient fabrication of N/O codoped carbons in pursuit of high performance supercapacitors.

 ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.xxx.



Page 22 of 32

XRD patterns and Raman spectra; Summary of XPS spectra; O1s and N1s high-resolution spectra; Equivalent circuit model and Nyquist plots; Detailed data regarding electrochemical performance; Comparison of the specific capacitances and energy storage of reported N-doped porous carbon electrodes in a two-electrode system using Na2SO4 and KOH electrolytes (PDF).

 AUTHOR INFORMATION Corresponding Authors *(M.L.) E-mail: [email protected]. *(L.G.) E-mail: [email protected]. ORCID Zhiwei Wang: 0000-0001-6729-2237 Yaokang Lv: 0000-0002-0077-9048 Liangchun Li: 0000-0002-2514-9528 Mingxian Liu: 0000-0002-9517-2985 Lihua Gan: 0000-0002-3652-8822 Notes The authors declare no competing financial interest.

 ACKNOWLEDGEMENTS This work was financially supported by the National Natural Science Foundation of China (Nos. 21875165, 51772216, and 21501135), the Science and Technology Commission of Shanghai Municipality, China (14DZ2261100), the Fundamental Research Funds for the Central Universities, and the Large Equipment Test Foundation of Tongji University.


Page 23 of 32 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


REFERENCE (1) Zhong, C.; Deng, Y.; Hu, W.; Qiao, J.; Zhang, L.; Zhang, J., A Review of Electrolyte Materials and Compositions for Electrochemical Supercapacitors. Chem. Soc. Rev. 2015, 44, 7484−7539. (2) Yang, Z.; Jing, R.; Zhang, Z.; Chen, X.; Guan, G.; Qiu, L.; Ye, Z.; Peng, H., Recent Advancement of Nanostructured Carbon for Energy Applications. Chem. Rev. 2015, 115, 5159−5342. (3) Zhu, Y.; Li, N.; Lv, T.; Yao, Y.; Peng, H.; Shi, J.; Cao, S.; Chen, T., Ag–Doped PEDOT:PSS/CNT Composites for Thin–Film All–Solid–State Supercapacitors with a Stretchability of 480%. J. Mater. Chem. A 2018, 6, 941−947. (4) Chen, Z.; Xie, H. Q.; Hu, L. F.; Chen, M.; Wu, L. M., Fabrication of Novel Lamellar Alternating Nitrogendoped Microporous Carbon Nanofilm/MoS2 Composites with High Electrochemical Properties. J. Mater. Chem. A 2017, 5, 22726−22734. (5) Lv, T.; Liu, M.; Zhu, D.; Gan, L.; Chen, T., Nanocarbon‐Based Materials for Flexible All‐Solid‐State Supercapacitors. Adv. Mater. 2018, 10, 1705489. (6) Wang, Y.; Tao, L.; Xiao, Z.; Chen, R.; Jiang, Z.; Wang, S., 3D Carbon Electrocatalysts in Situ Constructed by Defect‐Rich Nanosheets and Polyhedrons from Nacl‐Sealed Zeolitic Imidazolate Frameworks. Adv. Funct. Mater. 2018, 28, 1705356. (7) Yair, K.; Marcus, R.; Emanuel, K.; Lars, B.; Alexander, K.; Stefan, K.; Gleb, Y., High-Rate Electrochemical Capacitors Based on Ordered Mesoporous Silicon Carbide-Derived Carbon. ACS Nano 2010, 4, 1337−1344. (8) Shaibani, M.; Smith, S. J. D.; Banerjee, P. C.; Konstas, K.; Zafari, A.; Lobo, D. E.; Nazari, M.; Hollenkamp, A. F.; Hill, M. R.; Majumder, M., Framework-Mediated Synthesis of Highly Microporous Onion-Like Carbon: Energy Enhancement in Supercapacitors without Compromising



Page 24 of 32

Power. J. Mater. Chem. A 2017, 5, 2519−2529. (9) Xi, X.; Wu, D.; Han, L.; Yu, Y.; Su, Y.; Tang, W.; Liu, R., Highly Uniform Carbon Sheets with Orientation-Adjustable Ordered Mesopores. ACS Nano 2018, 12, 5436−5444. (10) Zhang, Y.; Zhao, C.; Ong, W. K.; Lu, X., Ultrafast-Freezing-Assisted Mild Preparation of Biomass-Derived, Hierarchically Porous, Activated Carbon Aerogels for High-Performance Supercapacitors. ACS Sustain. Chem. Eng. 2018, 7, 403−411. (11) Pan, S.; Lin, H.; Deng, J.; Chen, P.; Chen, X.; Yang, Z.; Peng, H., Novel Wearable Energy Devices Based on Aligned Carbon Nanotube Fiber Textiles. Adv. Energy Mater. 2015, 5, 1401438. (12) Lin, T.; Chen, I. W.; Liu, F.; Yang, C.; Bi, H.; Xu, F.; Huang, F., Nitrogen-Doped Mesoporous Carbon of Extraordinary Capacitance for Electrochemical Energy Storage. Science 2015, 350, 1508−1513. (13) Song, Z.; Zhu, D.; Li, L.; Chen, T.; Duan, H.; Wang, Z.; Lv, Y.; Xiong, W.; Liu, M.; Gan, L., An Ultrahigh Energy Density of N, O Codoped Carbon Nanospheres Based All-Solid-State Symmetric Supercapacitor. J. Mater. Chem. A 2019, 7, 1177–1186. (14) Song, Z.; Li, L.; Zhu, D.; Miao, L.; Duan, H.; Wang, Z.; Xiong, W.; Lv, Y.; Liu, M.; Gan, L., Synergistic Design of N, O Codoped Honeycomb Carbon Electrode and Ionogel Electrolyte Enabling All-Solid-State Supercapacitor with an Ultrahigh Energy Density. J. Mater. Chem. A 2019, 7, 816–826. (15) Wang, C.; Wu, D.; Wang, H.; Gao, Z.; Xu, F.; Jiang, K., A Green and Scalable Route to Yield Porous Carbon Sheets from Biomass for Supercapacitors with High Capacity. J. Mater. Chem. A 2017, 6, 1244−1254. (16) Xue, D.; Zhu, D.; Liu, M.; Duan, H.; Li, L.; Chai, X.; Wang, Z.; Lv, Y.; Xiong, W.; Gan, L., Schiff-Base/Resin Copolymer under Hypersaline Condition to High-Level N-Doped Porous ACS Paragon Plus Environment

Page 25 of 32 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


Carbon Nanosheets for Supercapacitors. ACS Appl. Nano Materials 2018, 1, 4998−5007. (17) Wang, Q.; Zhou, M.; Zhang, Y.; Liu, M.; Xiong, W.; Liu, S., Large Surface Area Porous Carbon Materials Synthesized by Direct Carbonization of Banana Peel and Citrate Salts for Use as High-Performance Supercapacitors. J. Mater. Sci: Mater. in Electron. 2017, 29, 4294−4300. (18) Gupta, K.; Liu, T.; Kavian, R.; Han, G. C.; Ryu, G. H.; Lee, Z.; Lee, S. W.; Kumar, S., High Surface Area Carbon from Polyacrylonitrile for High-Performance Electrochemical Capacitive Energy Storage. J. Mater. Chem. A 2016, 4, 18294−18299. (19) Ma, L.; Zhou, H.; Sun, Y.; Xin, S. L.; Xiao, C. H.; Kumatani, A.; Matsue, T.; Zhang, P. G.; Ding, S. J.; Li, F., Nanosheet-Structured NiCoO2/Carbon Nanotubes Hybrid Composite as a Novel Bifunctional Oxygen Electrocatalyst. Electrochim. Acta 2017, 252, 338−349. (20) Pang, J.; Zhang, W.; Zhang, H.; Zhang, J.; Zhang, H.; Cao, G.; Han, M.; Yang, Y., Sustainable Nitrogen-Containing Hierarchical Porous Carbon Spheres Derived from Sodium Lignosulfonate for High-Performance Supercapacitors. Carbon 2018, 132, 280−293. (21) Xiong, S.; Fan, J.; Wang, Y.; Zhu, J.; Yu, J.; Hu, Z., A Facile Template Approach to NitrogenDoped Hierarchical Porous Carbon Nanospheres from Polydopamine for High-Performance Supercapacitors. J. Mater. Chem. A 2017, 5, 18242−18252. (22) Hao, J.; Wang, J.; Qin, S.; Liu, D.; Li, Y.; Lei, W., B/N Co-Doped Carbon Nanosphere Frameworks as High-Performance Electrodes for Supercapacitors. J. Mater. Chem. A 2018, 6, 8053−8058. (23) Liu, Z.; Zhou, Z.; Xiong, W.; Zhang, Q., Controlled Synthesis of Carbon Nanospheres via the Modulation of the Hydrophilic Length of the Assembled Surfactant Micelles. Langmuir 2018, 34, 10389−10396. (24) Mostazo-López, M. J.; Ruiz-Rosas, R.; Castro-Muñiz, A.; Nishihara, H.; Kyotani, T.; ACS Paragon Plus Environment


Page 26 of 32

Morallón, E.; Cazorla-Amorós, D., Ultraporous Nitrogen-Doped Zeolite-Templated Carbon for High Power Density Aqueous-Based Supercapacitors. Carbon 2018, 129, 510−519. (25) Liu, J.; Yang, T.; Wang, D. W.; Lu, G. Q.; Zhao, D.; Qiao, S. Z., A Facile Soft-Template Synthesis of Mesoporous Polymeric and Carbonaceous Nanospheres. Nat. Commu. 2013, 4, 2798−2805. (26) Song, Z.; Zhu, D.; Xue, D.; Yan, J.; Chai, X.; Xiong, W.; Wang, Z.; Lv, Y.; Cao, T.; Liu, M.; Gan, L., Nitrogen-Enriched Hollow Porous Carbon Nanospheres with Tailored Morphology and Microstructure for All-Solid-State Symmetric Supercapacitors. ACS Appl. Energy Materials 2018, 1, 4293−4303. (27) Kondrat, S.; Wu, P.; Qiao, R.; Kornyshev, A. A., Erratum: Accelerating Charging Dynamics in Subnanometre Pores. Nat. Mater. 2014, 13, 387−393. (28) Hou, J.; Jiang, K.; Wei, R.; Tahir, M.; Wu, X.; Shen, M.; Wang, X.; Cao, C., Popcorn-Derived Porous Carbon Flakes with an Ultrahigh Specific Surface Area for Superior Performance Supercapacitors. ACS Appl. Mater. Interfaces 2017, 9, 30626−30634. (29) Luo, S.; Luo, Y.; Wu, H.; Li, M.; Yan, L.; Jiang, K.; Liu, L.; Li, Q.; Fan, S.; Wang, J., SelfAssembly of 3D Carbon Nanotube Sponges: A Simple and Controllable Way to Build Macroscopic and Ultralight Porous Architectures. Adv. Mater. 2016, 29, 1603549. (30) Lu, C.; Tranca, D.; Jian, Z.; Hernández, F. N. R. G.; Su, Y.; Zhuang, X.; Fan, Z.; Seifert, G.; Feng, X., Molybdenum Carbide-Embedded Nitrogen-Doped Porous Carbon Nanosheets as Electrocatalysts for Water Splitting in Alkaline Media. ACS Nano 2017, 11, 3933−3942. (31) Li, Y.; Wang, G.; Wei, T.; Fan, Z.; Yan, P., Nitrogen and Sulfur Co-Doped Porous Carbon Nanosheets Derived from Willow Catkin for Supercapacitors. Nano Energy 2016, 19, 165−175. (32) Niu, Q.; Gao, K.; Tang, Q.; Wang, L.; Han, L.; Fang, H.; Zhang, Y.; Wang, S.; Wang, L., ACS Paragon Plus Environment

Page 27 of 32 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


Large-Size Graphene-Like Porous Carbon Nanosheets with Controllable N-Doped Surface Derived from Sugarcane Bagasse Pith/Chitosan for High Performance Supercapacitors. Carbon 2017, 123, 290−298. (33) Liang, J.; Jiao, Y.; Jaroniec, M.; Qiao, S. Z., Sulfur and Nitrogen Dual-Doped Mesoporous Graphene Electrocatalyst for Oxygen Reduction with Synergistically Enhanced Performance. Angew. Chem. Int. Ed. 2012, 51, 11496−11500. (34) Li, S.; Chang, Y.; Yang, J.; Zhao, C.; Zhang, M.; Huang, H.; Liu, Z.; Wei, G.; Qiu, J., A Superhydrophilic “Nanoglue” for Stabilizing Metal Hydroxides onto Carbon Materials for HighEnergy and Ultralong-Life Asymmetric Supercapacitors. Energy Environ. Sci. 2017, 10, 1958−1965. (35) Zhang, S.; Tsuzuki, S.; Ueno, K.; Dokko, K.; Watanabe, M., Upper Limit of Nitrogen Content in Carbon Materials. Angew. Chem. Int. Ed. 2015, 54, 1302−1306. (36) Fahsi, K.; Dutremez, S. G.; Vioux, A.; Viau, L., Azole-Functionalized Diacetylenes as Precursors for Nitrogen-Doped Graphitic Carbon Materials. J. Mater. Chem. A 2013, 1, 4451−4461. (37) Krüner, B.; Schreiber, A.; Tolosa, A.; Quade, A.; Badaczewski, F.; Pfaff, T.; Smarsly, B. M.; Presser, V., Nitrogen-Containing Novolac-Derived Carbon Beadsas Electrode Material for Supercapacitors. Carbon 2018, 132, 220−231. (38) Ni, L.; Wang, R.; Wang, H.; Sun, C.; Sun, B.; Guo, X.; Jiang, S.; Shi, Z.; Jing, W.; Zhu, L.; Qiu, S.; Zhang, Z., Designing Nanographitic Domains in N-Doped Porous Carbon Foam for High Performance Supercapacitors. Carbon 2018, 139, 1152−1159. (39) Zhou, M.; Li, X.; Zhao, H.; Wang, J.; Zhao, Y.; Ge, F.; Cai, Z., Combined Effect of Nitrogen and Oxygen Heteroatoms and Micropores of Porous Carbon Frameworks from Schiff-Base ACS Paragon Plus Environment


Page 28 of 32

Networks on Their High Supercapacitance. J. Mater. Chem. A 2017, 6, 1621–1629. (40) Li, Z.; Chen, N.; Mi, H.; Ma, J.; Xie, Y.; Qiu, J., Hierarchical Hybrids Integrated by Dual Polypyrrole-Based Porous Carbons for Enhanced Capacitive Performance. Chem.-Eur. J 2017, 23, 13474−13481. (41) Zheng, L.; Wang, Z.; Zhang, M.; Chang, Y.; Gang, W.; Dong, Y.; Liu, S.; Wang, Y.; Qiu, J., Sustainable Synthesis and Assembly of Biomass-Derived B/N Co-Doped Carbon Nanosheets with Ultrahigh Aspect Ratio for High-Performance Supercapacitors. Adv. Funct. Mater. 2016, 26, 111−119. (42) Wei, J.; Ding, H.; Wang, Y.; Xiong, H., Hierarchical Porous Carbon Materials with High Capacitance Derived from Schiff-Base Networks. ACS Appl. Mater. Interfaces 2015, 7, 5811−5819. (43) Zhu, D.; Jiang, J.; Sun, D.; Qian, X.; Wang, Y.; Li, L.; Wang, Z.; Chai, X.; Gan, L.; Liu, M., A General Strategy to Synthesize High-Level N-Doped Porous Carbons via Schiff-Base Chemistry for Supercapacitors. J. Mater. Chem. A 2018, 6, 12334–12343. (44) Zhang, Y.; Zhu, J.; Ren, H.; Bi, Y.; Zhang, L., Synthesis and Properties of Melamine–Starch Hybrid Aerogels Cross-Linked with Formaldehyde. J. Sol-Gel Sci. Techn. 2017, 83, 1−9. (45) Wang, X.; Li, C.; Zhao, T., Fabrication and Characterization of Poly(MelamineFormaldehyde)/Silicon Carbide Hybrid Microencapsulated Phase Change Materials with Enhanced Thermal Conductivity and Light-Heat Performance. Sol. Energy Mat. Sol. C. 2018, 183, 82−91. (46) León, G.; Paret, N.; Fankhauser, P.; Grenno, D.; Erni, P.; Ouali, L.; Berthier, D. L., Formaldehyde-Free Melamine Microcapsules as Core/Shell Delivery Systems for Encapsulation of Volatile Active Ingredients. RSC Adv. 2017, 7, 18962−18975. (47) Xuedong Xi; Antonio Pizzi; Amirou, S., Melamine–Glyoxal–Glutaraldehyde Wood Panel ACS Paragon Plus Environment

Page 29 of 32 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


Adhesives without Formaldehyde. Polymers 2017, 10, 667−684. (48) Lei, Z.; Christov, N.; Zhang, L. L.; Zhao, X. S., Mesoporous Carbon Nanospheres with an Excellent Electrocapacitive Performance. J. Mater. Sci: Mater. 2011, 21, 2274–2281. (49) Lian, C.; Jiang, D.; Liu, H.; Wu, J., A Generic Model for Electric Double Layers in Porous Electrodes. J. Phys. Chem. C 2016, 120, 8704−8710. (50) Thommes, M.; Kaneko, K.; Neimark, A. V.; Olivier, J. P.; Rodriguez-Reinoso, F.; Rouquerol, J.; Sing, K. S. W., Physisorption of Gases, with Special Reference to the Evaluation of Surface Area and Pore Size Distribution (Iupac Technical Report). Pure Appl. Chem. 2015, 87, 1051–1069. (51) Chmiola, J.; Yushin, G.; Gogotsi, Y.; Portet, C.; Simon, P.; Taberna, P. L., Anomalous Increase in Carbon Capacitance at Pore Sizes Less Than 1 Nanometer. Science 2006, 313, 1760−1763. (52) Meng, J.; Niu, C.; Xu, L.; Li, J.; Liu, X.; Wang, X.; Wu, Y.; Xu, X.; Chen, W.; Li, Q.; Zhu, Z.; Zhao, D.; Mai, L., General Oriented Formation of Carbon Nanotubes from Metal-Organic Frameworks. J. Am. Chem. Soc. 2017, 139, 8212−8221. (53) Qin, F.; Tian, X.; Guo, Z.; Shen, W., Asphaltene-Based Porous Carbon Nanosheet as Electrode for Supercapacitor. ACS Sustain. Chem. Eng. 2018, 6, 15708−15719. (54) Zhang, R.; Wang, L.; Zhao, J.; Guo, S., Effects of Sodium Alginate on the Composition, Morphology, and Electrochemical Properties of Electrospun Carbon Nanofibers as Electrodes for Supercapacitors. ACS Sustain. Chem. Eng. 2019 7, 632−640 (55) Wang, J.; Zhang, P.; Liu, L.; Zhang, Y.; Yang, J.; Zeng, Z.; Deng, S., Controllable Synthesis of Bifunctional Porous Carbon for Efficient Gas-Mixture Separation and High-Performance Supercapacitor. Chem. Eng. J. 2018, 348, 57−66. (56) Meng, X.; Yu, C.; Zhang, X.; Huang, L.; Rager, M.; Hong, J.; Qiu, J.; Lin, Z., Active SitesACS Paragon Plus Environment


Page 30 of 32

Enriched Carbon Matrix Enables Efficient Triiodide Reduction in Dye-Sensitized Solar Cells: An Understanding of the Active Centers. Nano Energy 2018, 54, 138−147. (57) Wan, L.; Wang, J.; Xie, L.; Sun, Y.; Li, K., Nitrogen-Enriched Hierarchically Porous Carbons Prepared from Polybenzoxazine for High-Performance Supercapacitors. ACS Appl. Mater. Interfaces 2014, 6, 15583−15596. (58) Yuan, C.; Liu, X.; Jia, M.; Luo, Z.; Yao, J., Facile Preparation of N- and O-Doped Hollow Carbon Spheres Derived from Poly(O-Phenylenediamine) for Supercapacitors. J. Mater. Chem. A 2015, 3, 3409–3415. (59) Liu, B.; Liu, Y.; Chen, H.; Yang, M.; Li, H., Oxygen and Nitrogen Co-Doped Porous Carbon Nanosheets Derived from Perilla Frutescens for High Volumetric Performance Supercapacitors. J. Power Sources 2017, 341, 309−317. (60) Yuan, D. S.; Zhou, T. X.; Zhou, S. L.; Zou, W. J.; Mo, S. S.; Xia, N. N., Nitrogen-Enriched Carbon Nanowires from the Direct Carbonization of Polyaniline Nanowires and Its Electrochemical Properties. Electrochem. Commun. 2011, 13, 242−246. (61) Pan, L.; Wang, Y.; Hu, H.; Li, X.; Liu, J.; Guan, L.; Tian, W.; Wang, X.; Li, Y.; Wu, M., 3D Self-Assembly Synthesis of Hierarchical Porous Carbon from Petroleum Asphalt for Supercapacitors. Carbon 2018, 134, 345–353. (62) Ouyang, T.; Zhang, T.; Wang, H.; Yang, F.; Yan, J.; Zhu, K.; Ye, K.; Wang, G.; Zhou, L.; Cheng, K.; Cao, D., High-Throughput Fabrication of Porous Carbon by Chemical Foaming Strategy for High Performance Supercapacitor. Chem. Eng. J. 2018, 352, 459−468. (63) Zhao, Y.; He, X.; Chen, R.; Liu, Q.; Liu, J.; Yu, J.; Li, J.; Zhang, H.; Dong, H.; Zhang, M., A Flexible

All-Solid-State

Asymmetric

Supercapacitors

Based

on

Hierarchical

Carbon

Cloth@CoMoO4@NiCo Layered Double Hydroxide Core-Shell Heterostructures. Chem. Eng. J. ACS Paragon Plus Environment

Page 31 of 32 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


2018, 352, 29−38. (64) Hu, F.; Wang, J.; Hu, S.; Li, L.; Wang, G.; Qiu, J.; Jian, X., Inherent N,O-Containing Carbon Frameworks as Electrode Materials for High-Performance Supercapacitors. Nanoscale 2016, 8, 16323-16331. (65) Sun, K.; Yu, S.; Hu, Z.; Li, Z.; Lei, G.; Xiao, Q.; Ding, Y., Oxygen-Containing Hierarchically Porous Carbon Materials Derived from Wild Jujube Pit for High-Performance Supercapacitor. Electrochim. Acta 2017, 231, 417−428. (66) Ding, B.; Guo, D.; Wang, Y.; Wu, X.; Fan, Z., Functionalized Graphene Nanosheets Decorated on Carbon Nanotubes Networks for High Performance Supercapacitors. J. Power Sources 2018, 398, 113–119. (67) Qin, B.; Wang, Q.; Zhang, X.; Xie, X.; Jin, L. e.; Cao, Q., One-Pot Synthesis of Interconnected Porous Carbon Derived from Coal Tar Pitch and Cellulose for High-Performance Supercapacitors. Electrochim. Acta 2018, 283, 655−663. (68) Zhao, Z.; Xie, Y., Electrochemical Supercapacitor Performance of Boron and Nitrogen CoDoped Porous Carbon Nanowires. J. Power Sources 2018, 400, 264–276. (69) Su, X. L.; Cheng, M. Y.; Fu, L.; Yang, J. H.; Zheng, X. C.; Guan, X. X., Superior Supercapacitive Performance of Hollow Activated Carbon Nanomesh with Hierarchical Structure Derived from Poplar Catkins. J. Power Sources 2017, 362, 27−38.



Page 32 of 32

For Table of Contents Use Only Ultramicro-, supermicro- and mesoporous carbon spheres with high-level N/O dopants are fabricated via a template-free, self-doped strategy for high-performance supercapacitors.


Template-Free, Self-Doped Approach to Porous Carbon Spheres with

Recommend Documents