Co-reporter:Chongyang Yang, Minqiang Sun, Gengchao Wang, Qilin Cheng, Hua Bao, Xingwei Li, Nabanita Saha, Petr Saha
Chemical Engineering Journal 2017 Volume 326(Volume 326) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.cej.2017.05.094
•Unique GNS/aMWCNT@PANI nanocone arrays are synthesized by an interfacial polymerization.•Optimal oASC matching GNS/aMWCNT@PDAA anode with GNS/aMWCNT@PANI cathode is achieved.•As-assembled oASC exhibits superhigh energy density of 96.9 Wh kg−1.Nowadays, high energy density is greatly imperative for supercapacitor technologies, which focus on both high-performance electrodes and assembling techniques. Here, we synthesized a promising cathode of graphene/acid-treated carbon nanotubes (GNS/aMWCNT)-supported polyaniline nanocone arrays by an interfacial polymerization, which achieves high specific capacitance of 299 F g−1 in 1 M tetraethylammonium tetrafluoroborate-acetonitrile (Et4NBF4-AN) with the potential window of −0.6 to 0.8 V (vs. Ag/Ag+). Matching it with GNS/aMWCNT-supported poly(1,5-diaminoanthraquinone) nanoparticles anode, the organic asymmetric supercapacitors (oASCs) are perfectly fabricated. The oASC with anode/cathode mass ratio of 1/1 delivers the highest energy density of 96.9 Wh kg−1, excellent rate capability (retain 65.6 Wh kg−1 even at 65.7 kW kg−1) and superior cycling stability (94.2% retention after 5000 cycles), which is superior or comparable to other π-conjugated polymers-based organic supercapacitors.Download high-res image (84KB)Download full-size image
Co-reporter:Shuangmin Yu, Fan Qin and Gengchao Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 7) pp:1504-1510
Publication Date(Web):04 Jan 2016
DOI:10.1039/C5TC04026D
The introduction of conductive polymers can significantly improve the dielectric constant of polymer-based materials but results in overly large increases of dielectric loss. Herein, uniform-sized and easily dispersed polyaniline nanorods (dPANI@PVP) were synthesized by applying a dynamically interfacial polymerization method and encapsulating the nanorods with poly(vinyl pyrrolidone) (PVP). The synthesized dPANI@PVP was then used to fabricate poly(vinylidene fluoride)-based (PVDF) nanocomposites that displayed a high dielectric constant and low dielectric loss. Morphological and structural analyses showed the insulating PVP shell to have a thickness of 5–10 nm and to be wrapped on the dPANI nanorod surface, which not only provided a barrier layer between the conductive dPANI nanorods, but also facilitated an excellent dispersion of dPANI nanorods in the PVDF matrix. As a result, the dPANI@PVP/PVDF nanocomposites showed a relatively low dielectric loss while maintaining a sufficiently high dielectric constant. Specifically, when the loading of dPANI@PVP was 9.5 wt%, the dielectric constant of the nanocomposite reached 174 at 100 Hz, which is about 20 times higher than that of pure PVDF. Moreover, there was only a small increase of the dielectric loss from 0.06 for pure PVDF to 0.17 for the nanocomposite.
Co-reporter:Qianqiu Tang, Wenqiang Wang, and Gengchao Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 41) pp:27701
Publication Date(Web):September 23, 2016
DOI:10.1021/acsami.6b08966
Research on stretchable energy-storage devices has been motivated by elastic electronics, and considerable research efforts have been devoted to the development of stretchable electrodes. However, stretchable electrolytes, another critical component in stretchable devices, have earned quite little attention, especially the alkali-resistant ones. Here, we reported a novel stretchable alkali-resistant electrolyte made of a polyolefin elastomer porous membrane supported potassium hydroxide–potassium polyacrylate (POE@KOH–PAAK). The as-prepared electrolyte shows a negligible plastic deformation even after 1000 stretching cycles at a strain of 150% as well as a high conductivity of 0.14 S cm–1. It also exhibits excellent alkali resistance, which shows no obvious degradation of the mechanical performance after immersion in 2 M KOH for up to 2 weeks. To demonstrate its good properties, a high-performance stretchable supercapacitor is assembled using a carbon-nanotube-film-supported NiCo2O4 (CNT@NiCo2O4) as the cathode and Fe2O3 (CNT@Fe2O3) as the anode, proving great application promise of the stretchable alkali-resistant electrolyte in stretchable energy-storage devices.Keywords: alkaline-resistant; polyacrylate; stretchable electrolyte; supercapacitor
Co-reporter:Han Li, Liping Sun, and Gengchao Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 9) pp:6061
Publication Date(Web):February 18, 2016
DOI:10.1021/acsami.5b12496
The novel polyethylene glycol-grafted multiwalled carbon nanotube/sulfur (PEG-CNT/S) composite cathodes with nest-like structure are fabricated through a facile combination process of liquid phase deposition and self-assembly, which consist of the active material core of sulfur particle and the conductive shell of PEG-CNT network. The unique architecture not only provides a short and rapid charge transfer pathway to improve the reaction kinetics but also alleviates the volume expansion of sulfur during lithiation and minimizes the diffusion of intermediate polysulfides. Such an encouraging electrochemical environment ensures the excellent rate capability and high cycle stability. As a result, the as-prepared PEG-CNT/S composite with sulfur content of 75.9 wt % delivers an initial discharge capacity of 1191 and 897 mAh g–1 after 200 cycles at 0.2 C with an average Coulombic efficiency of 99.5%. Even at a high rate of 2 C, an appreciable capacity of 723 mAh g–1 can still be obtained.Keywords: carbon nanotube; lithium−sulfur batteries; nest-like structure; polyethylene glycol; self-assembly
Co-reporter:Lei Cao, Qianqiu Tang and Gengchao Wang
RSC Advances 2016 vol. 6(Issue 35) pp:29592-29597
Publication Date(Web):16 Mar 2016
DOI:10.1039/C6RA02859D
Poly(3,4-ethylenedioxythiophene) (PEDOT) is a promising conductive polymer due to its high conductivity and optical transparency. However, two main challenges remain to be solved for its practical application, including improving the humidity stability and water resistance. Here, a novel cross-linkable copolymer of methacryloyloxyethyl isocyanate grafted poly(styrene sulfonate-co-2-hydroxyethyl acrylate) [MOI-P(SS-HEA)] is synthesized by a radical polymerization and condensation reaction. MOI-P(SS-HEA) is used as a multi-functional counter anion to obtain the UV-curable conductive dispersion of PEDOT:MOI-P(SS-HEA). The electrical conductivity, humidity stability, and water resistance of the cross-linked PEDOT:MOI-P(SS-HEA) [PEDOT:MOI-P(SS-HEA)-C] conductive films are investigated. The results indicate that the UV cross-linked reaction significantly improves the humidity stability and water resistance of the PEDOT:MOI-P(SS-HEA)-C conductive film.
Co-reporter:Tao Zhang;Han Li;Qianqiu Tang;Minqiang Sun
Journal of Solid State Electrochemistry 2016 Volume 20( Issue 8) pp:2169-2177
Publication Date(Web):2016 August
DOI:10.1007/s10008-016-3215-6
Organic compounds become promising candidates for cathodes of rechargeable lithium battery (RLB) due to the high theoretical capacity and improved safety. However, they exhibit low conductivity and easy dissolution in electrolyte, which leads to the low utilization of active materials and poor cycling stability of RLBs. Here, we synthesize a novel composite of activated hierarchical porous carbon supporting poly(1,5-diamino-anthraquinone) (aHPC@PDAA), using Ce(SO4)2 as oxidant and naphthalenesulfonic acid (NSA) as soft template for PDAA. The as-synthesized composite exhibits uniformly nanoporous structure with nano-sized PDAA particles distributed homogenously inside and outside of pores. The aHPC@PDAA cathode for RLBs achieves high electrochemical performance with a discharge capacity as much as 250 mAh g−1 at the current density of 100 mA g−1, which still maintains 176 mAh g−1 after 2000 charging-discharging cycles.
Co-reporter:Qianqiu Tang, Wenqiang Wang and Gengchao Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 12) pp:6662-6670
Publication Date(Web):16 Feb 2015
DOI:10.1039/C5TA00328H
The real-world applications of supercapacitors are hindered by their relatively low energy density compared with rechargeable batteries. Even with tremendous efforts in developing cathodes for aqueous asymmetric supercapacitors (AASCs), their supercapacitive performance is still severely restricted by the low specific capacitance of anodes which mostly consist of carbonaceous materials. We developed a novel low-cost anode of homogenous Fe2O3 nanowires grown on carbon fiber paper (CFP) that achieves a high specific capacitance of 908 F g−1 at 2 A g−1 and excellent rate performance (90% capacitance retention up to 10 A g−1) in a wide negative potential window of 0 to −1.35 V. Such an excellent supercapacitive performance makes it a perfect anode compared with other reported ones. Matching it with the NiO nanoflake cathode (1520 F g−1 at 2 A g−1 in 0–0.45 V) on CFP, an extremely high energy density of 105 W h kg−1 is obtained at a power density of 1400 W kg−1 and still retains 72.6 W h kg−1 at 12700 W kg−1 for the AASCs, which is much superior to previously reported AASCs and even exceeding those of Ni-MH batteries.
Co-reporter:Minqiang Sun, Gengchao Wang, Chongyang Yang, Hao Jiang and Chunzhong Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 7) pp:3880-3890
Publication Date(Web):02 Jan 2015
DOI:10.1039/C4TA06728B
Supercapacitors based on π-conjugated conducting polymers have attracted attention due to their high pseudo-capacitance characteristics. However, the narrow window of their potential (<1 V) gives rise to low energy density, and this restricts their practical application. In the present study a novel hierarchical nanocomposite, graphene nanosheets/acid-treated multi-walled carbon nanotube-supported poly(1,5-diaminoanthraquinone) (GNS/aMWCNT@PDAA), has been successfully synthesized using cerium sulphate (Ce(SO4)2) as oxidant and camphor sulphonic acid as dopant. The nanocomposite exhibits a unique nanoporous morphology, a high π-conjugated degree and an excellent conductive interpenetrating network. With these intriguing features, in addition to its unique p- and n-doping characteristics, the supercapacitor in a 1 M tetraethylammonium tetrafluoroborate -acetonitrile (Et4NBF4-AN) electrolyte can be reversibly cycled within a potential window of 2.8 V. The supercapacitor achieves a high energy density of 86.4 W h kg−1 at a power density of 0.73 kW kg−1, and still retains energy density of 55.5 W h kg−1 at a power density of 153.9 kW kg−1. In addition, superior cycling stability is achieved, with only 7% capacitance loss after 10000 cycles. This excellent performance surpasses that of other recently reported supercapacitors and represents a significant breakthrough in π-conjugated polymer-based supercapacitors.
Co-reporter:Qianqiu Tang, Mingming Chen, Chongyang Yang, Wenqiang Wang, Hua Bao, and Gengchao Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 28) pp:15303
Publication Date(Web):June 29, 2015
DOI:10.1021/acsami.5b03148
With the advantages of high stickiness and stretchability of the hydrogel electrolyte as well as the resilient properties of film electrodes, the facile “prestrain-stick-release” strategy can be utilized for the assembly of a stretchable supercapacitor. Two major issues of concern are the relatively low mechanical strength of the hydrogel electrolyte and the low energy density of the assembled device. Herein, vinyl group grafted silica (CH2═CH—SiO2) nanoparticles were used as a nanoparticle cross-linker for polyacrylamide (PAAM), enhancing the tensile strength of 844 kPa at the strain of 3400% for the KCl—CH2═CH—SiO2/PAAM hydrogel electrolyte. Besides, carbon nanotube supported polypyrrole (CNT@PPy) and manganese dioxide (CNT@MnO2) film electrodes are prepared to assemble the stretchable asymmetric CNT@MnO2//KCl—CH2═CH—SiO2/PAAM//CNT@PPy supercapacitor, significantly enhancing the potential window to 0–2.0 V and achieving a high energy density of 40 Wh kg–1 at the power density of 519 kW kg–1 with the strain of 100%, which is the best known for the reported stretchable supercapacitors.Keywords: manganese dioxide; polypyrrole; stretchable asymmetric supercapacitor; stretchable hydrogel electrolyte; wrinkled electrodes;
Co-reporter:Qianqiu Tang, Mingming Chen, Gengchao Wang, Hua Bao, Petr Saha
Journal of Power Sources 2015 Volume 284() pp:400-408
Publication Date(Web):15 June 2015
DOI:10.1016/j.jpowsour.2015.03.059
•A facile prestrain-stick-release assembly is developed for a highly stretchable supercapacitor.•A novel Na2SO4-aPUA/PAAM hydrogel electrolyte with high stretchability, electrical conductivity and stickiness is developed.•The stickiness of the hydrogel electrolyte ensures its close interface contact with film electrodes.A facile prestrain-stick-release assembly strategy for the stretchable supercapacitor device is developed based on a novel Na2SO4-aPUA/PAAM hydrogel electrolyte, saving the stretchable rubber base conventionally used. The Na2SO4-aPUA/PAAM hydrogel electrolyte exhibits high stretchability (>1000%), electrical conductivity (0.036 S cm−1) and stickiness. Due to the unique features of the hydrogel electrolyte, the carbon nanotube@MnO2 film electrodes can be firmly stuck to two sides of the prestrained hydrogel electrolyte. Then, by releasing the hydrogel electrolyte, homogenous buckles are formed for the film electrodes to get a full stretchable supercapacitor device. Besides, the high stickiness of the hydrogel electrolyte ensures its strong adhesion with the film electrodes, facilitating ion and electronic transfer of the supercapacitor. As a result, excellent electrochemical performance is achieved with the specific capacitance of 478.6 mF cm−2 at 0.5 mA cm−2 (corresponding to 201.1 F g−1) and capacitance retention of 91.5% after 3000 charging–discharging cycles under 150% strain, which is the best for the stretchable supercapacitors.A highly stretchable supercapacitor with significantly improved electrochemical performance is fabricated by a facile prestrain-stick-release assembly strategy.
Co-reporter:Chongyang Yang, Minqiang Sun, Xi Wang, and Gengchao Wang
ACS Sustainable Chemistry & Engineering 2015 Volume 3(Issue 9) pp:2067
Publication Date(Web):July 17, 2015
DOI:10.1021/acssuschemeng.5b00334
High energy density and safety are the goals in the pursuit of flexible energy storage devices. Herein, we report a novel flexible supercapacitor (SC) fabricated with a cross-linked poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) porous organogel electrolyte and carbon nanotube paper@poly(1,5-diaminoanthraquinone) (CNT@PDAA) film electrodes. The PVDF-HFP/tetraethylammonium tetrafluoroborate-acetonitrile (Et4NBF4-AN) organogel electrolyte, featured with a highly porous structure and chemical cross-linking, exhibits nonflammability, a broad electrochemical stable window, and high ionic conductivity of 14.4 × 10–3 S cm–1, as well as improved solvent resistance. The CNT@PDAA electrode displays good pseudocapacitive performance in a broad potential window due to p- and n-doping characteristics. Because of this rational design, the as-prepared flexible SC device achieves an excellent volumetric capacitance of 5.2 F cm–3 and a high energy density of 5.16 mWh cm–3 (41.4 Wh kg–1) at a power density of 0.051 W cm–3 (0.41 kW kg–1). More importantly, a unit of as-assembled SC is shown to drive a commercially available product even in a bent state.Keywords: Cross-linked; Flexible supercapacitor; Irradiation; Organogel electrolyte; Poly(1,5-diaminoanthraquinone); Poly(vinylidene fluoride-co-hexafluoropropylene);
Co-reporter:Dechao Lv, Jiali Shen and Gengchao Wang
RSC Advances 2015 vol. 5(Issue 31) pp:24599-24606
Publication Date(Web):27 Feb 2015
DOI:10.1039/C4RA13737J
A post-oxidation strategy was proposed to synthesize sulfonated graphene nanosheets/carboxylated multi-walled carbon nanotube-supported PANI (sGNS/cMWCNT@PANI) hierarchical nanocomposites by an interfacial polymerization as advanced supercapacitor electrodes. Field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM) indicated that the morphology with a coexisting structure of sGNS supported PANI nanorod arrays and coaxial cMWCNT/PANI nanocables did not show significant differences through a post-oxidation process. X-ray diffraction (XRD) and thermogravimetic analysis (TGA) proved that the oligomers of PANI were eliminated during the post-oxidation process. The spectral analysis revealed that the post-oxidation led to an increasing content of quinoid structure in the nanocomposites. Electrochemical measurements showed that the sGNS/cMWCNT@PANI with a post-oxidation process exhibited improved cycling stability with 91.4% capacitance retention after 5000 cycles.
Co-reporter:Han Li, Minqiang Sun, Tao Zhang, Yuqian Fang and Gengchao Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 43) pp:18345-18352
Publication Date(Web):04 Sep 2014
DOI:10.1039/C4TA03366C
A novel PEDOT-PSS coated sulfur@activated porous graphene composite (PEDOT/S@aPG) is prepared by the impregnation of sulfur with aPG and encapsulation with PEDOT-PSS as the cathode material for lithium–sulfur batteries. The abundant nanopores and large surface area of aPG can provide an intimate contact and strong interaction with S species. Furthermore, the conductive PEDOT-PSS layer can facilitate the charge transportation and prevent the dissolution of polysulfides. As a result, the as-prepared PEDOT/S@aPG composite cathode with a sulfur content of about 60.1% shows a higher specific discharge capacity (1198 mA h g−1 at 0.1 C) in the first cycle and good cycling stability, retaining a reversible capacity of 845 mA h g−1 after 200 cycles. Moreover, the PEDOT/S@aPG cathode also exhibits excellent rate capability, showing a high reversible capacity of 718 mA h g−1 at 2 C.
Co-reporter:Chongyang Yang, Jiali Shen, Chunyan Wang, Haojie Fei, Hua Bao and Gengchao Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 5) pp:1458-1464
Publication Date(Web):07 Nov 2013
DOI:10.1039/C3TA13953K
Sandwich-like reduced graphene oxide/carboxylated multi-walled carbon nanotube (RGO/cMWCNT) hybrid film and the carbon fiber paper-supported polypyrrole (CFP/PPy) composite film were prepared by a vacuum-infiltration process and an electrochemical deposition method, respectively. Furthermore, a novel all-solid-state asymmetric supercapacitor (ASC) was fabricated using RGO/cMWCNT as the negative electrode and CFP/PPy as the positive electrode, separated with potassium polyacrylate/KCl gel electrolyte. Due to the unique structure, stable potential window and good capacitive performance of the two electrodes, the as-fabricated ASC can be cycled reversibly at a cell voltage of 1.6 V and displays outstanding performances with an energy density of 28.6 W h kg−1 and a power density of 15.1 kW kg−1. Additionally, our ASC device also presents a superior long cycle life with 93% capacitance retention after 2000 cycles.
Co-reporter:Haojie Fei, Chongyang Yang, Hua Bao, Gengchao Wang
Journal of Power Sources 2014 Volume 266() pp:488-495
Publication Date(Web):15 November 2014
DOI:10.1016/j.jpowsour.2014.05.059
•A method is proposed to prepare cross-linked PVA–H2SO4 porous gel electrolyte.•PVA porous membranes possess higher swelling ratio to H2SO4 aqueous solution.•Graphene/CB films exhibit improved specific capacitance compared to graphene film.•A flexible SC based on PVA porous gel electrolyte shows good performance at 70 °C.Flexible all-solid-state supercapacitors (SCs) are fabricated using graphene/carbon black nanoparticle (GCB) film electrodes and cross-linked poly(vinyl alcohol)–H2SO4 porous gel electrolytes (gPVAP–H2SO4). The GCB composite films, with carbon black (CB) nanoparticles uniformly distributed in the graphene nanosheets, greatly improve the active surface areas and ion transportation of pristine graphene film. The porous structure of as-prepared gPVAP–H2SO4 membrane improves the equilibrium swelling ratio in electrolyte and provides interconnected ion transport channels. The chemical crosslinking solves the fluidity problem of PVA–H2SO4 gel electrolyte at high temperature. As-fabricated GCB//gPVAP(20)–H2SO4//GCB flexible SC displays an increased specific capacitance (144.5 F g−1 at 0.5 A g−1) and a higher specific capacitance retention (67.9% from 0.2 to 4 A g−1). More importantly, the flexible SC possesses good electrochemical performance at high temperature (capacitance retention of 78.3% after 1000 cycles at 70 °C).
Co-reporter:Qianqiu Tang, Jun Sun, Shuangmin Yu and Gengchao Wang
RSC Advances 2014 vol. 4(Issue 69) pp:36584-36590
Publication Date(Web):06 Aug 2014
DOI:10.1039/C4RA04225E
Improving thermal conductivity and decreasing supercooling are essential for the utilization of paraffin phase change materials (PCMs). In this work, n-octadecylamine-functionalized multi-walled carbon nanotubes (f-MWCNTs) are obtained through a simple method of carboxylation of the MWCNTs with mixed acids of H2SO4 and HNO3 and then salt-forming reaction with n-octadecylamine. The paraffin/f-MWCNTs (paraffin/f-MWCNTs) composite PCMs are fabricated by mixing paraffin with f-MWCNTs under ultrasonication at 70 °C. It is found that the f-MWCNTs are homogenously dispersed in a toluene or paraffin matrix due to the existence of long chain alkanes in f-MWCNTs. As a result, the thermal conductivity and heat transfer of the paraffin/f-MWCNTs composite PCMs are significantly enhanced. Moreover, differential scanning calorimetry (DSC) analysis indicates that the incorporation of f-MWCNTs reduces the supercooling of paraffin, mainly due to the well-dispersed f-MWCNTs serving as nuclei to promote the heterogeneous nucleation and crystallization process of paraffin.
Co-reporter:Minqiang Sun, Qianqiu Tang, Tao Zhang and Gengchao Wang
RSC Advances 2014 vol. 4(Issue 15) pp:7774-7779
Publication Date(Web):10 Jan 2014
DOI:10.1039/C3RA47806H
Novel π-conjugated poly(1,5-diaminoanthraquinone) (PDAA) is successfully synthesized using Ce(SO4)2 with suitable redox potential through controlling polymerization temperature. The as-prepared PDAA under optimal conditions displays homogeneous submicron particles, excellent π-conjugated structure as well as high conductivity (1.15 × 10−3 S cm−1). Such unique features make the PDAA an ideal electrode material for electrochemical energy storage. As a supercapacitor electrode, the PDAA exhibits a high specific capacitance (406.3 F g−1), desirable rate performance as well as superior cycle life (9.3% capacitance loss after 20000 cycles). This simple and cost-effective method without any external additives and stabilizers may provide valuable guidance for the rational preparation of other novel micro-nanostructure π-conjugated conducting polymers.
Co-reporter:Mingfeng Chen;Pulan Xiong;Quan Zhou;Lizhong Ni
Polymer International 2014 Volume 63( Issue 8) pp:1531-1536
Publication Date(Web):
DOI:10.1002/pi.4661
Abstract
Three novel kinds of linear silicon-containing hybrid polymers with Si−C≡C units were synthesized by polycondensation reactions using the Grignard reagent method. All the polymers were thermosetting, highly heat-resistant, moldable and easily soluble in common organic solvents. The structure, curing behavior, thermal and oxidative properties were characterized using Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. The results obtained can provide theoretical guidance for determining the curing of the resin system. In addition, the cured polymers exhibit excellent thermal and oxidative stabilities with temperatures of 5% weight loss (Td5) above 480 °C and 450 °C in nitrogen and air respectively; the residues at 1000 °C were above 70.0% and 45.0% respectively. The thermal and oxidative stabilities of the polymers are attributed to a crosslinking reaction between the Si−H and C≡C bonds or C≡C bonds. These polymers have the potential for use as high-temperature-resistant resins and ceramic precursors. © 2013 Society of Chemical Industry
Co-reporter:Jiali Shen, Chongyang Yang, Xingwei Li, and Gengchao Wang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 17) pp:8467
Publication Date(Web):August 9, 2013
DOI:10.1021/am4028235
Hierarchical sulfonated graphene nanosheet/carboxylated multiwalled carbon nanotube/polyaniline (sGNS/cMWCNT/PANI) nanocomposites were synthesized through an interfacial polymerization method. Activated porous graphene (aGNS) was prepared by combining chemical foaming, thermal reduction, and KOH activation. Furthermore, we have successfully fabricated an asymmetric supercapacitor (ASC) using sGNS/cMWCNT/PANI and aGNS as the positive and negative electrodes, respectively. Because of its unique structure, high capacitive performance, and complementary potential window, the ASC device can be cycled reversibly at a cell voltage of 1.6 V in a 1 M H2SO4 aqueous electrolyte, delivering a high energy density of 20.5 Wh kg–1 at a power density of 25 kW kg–1. Moreover, the ASC device also exhibits a superior long cycle life with 91% retention of the initial specific capacitance after 5000 cycles.Keywords: activation; asymmetric supercapacitor; carbon nanotubes; graphene; interfacial polymerization; nanostructured polyaniline;
Co-reporter:Guangxiang Wang, Qianqiu Tang, Hua Bao, Xingwei Li, Gengchao Wang
Journal of Power Sources 2013 Volume 241() pp:231-238
Publication Date(Web):1 November 2013
DOI:10.1016/j.jpowsour.2013.04.122
•The MnO2/PANI nanoparticles with 5–10 nm were uniformly deposited onto sulfonated graphene nanosheets.•Ternary composite shows high electrical conductivity and surface area compared to MnO2/PANI.•Ternary composite exhibits superior rate capability and excellent cycling stability.A novel ternary composite of sulfonated graphene/MnO2/polyaniline (sGMOPANI) is synthesized via a dilute in-situ polymerization method using potassium permanganate as oxidant under neutral condition. The FE-SEM and HRTEM images show that MnO2/polyaniline nanoparticles with the diameter of 5–10 nm deposit onto sulfonated graphene nanosheets. Spectral analysis reveals the existence of the hydrogen bond and π–π interaction between MnO2/polyaniline nanoparticles and sulfonated graphene. As a result, the sGMOPANI composite based on the two-electrode cell shows improved electrochemical capacitance (276 F g−1 at 1 g−1 in 1 M Na2SO4), better rate capability (73% capacitance retention from 0.2 to 20 A g−1), and higher cycling stability (11.7% capacitance loss after 3000 cycles) compared to the MnO2/polyaniline binary composite.
Co-reporter:Ting-yu Chi, Han Li, Xing-wei Li, Hua Bao, Geng-chao Wang
Electrochimica Acta 2013 Volume 96() pp:206-213
Publication Date(Web):30 April 2013
DOI:10.1016/j.electacta.2013.02.100
A novel composite of hierarchically porous carbon (HPC) supported PDMcT–PANI (HPC/PDMcT–PANI) was synthesized through an in situ oxidative polymerization. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectra showed that a partial amount of PDMcT was parasitized inside of pores of HPC and some other amount of PDMcT formed interpenetrated fibrous electron donor–acceptor PDMcT–PANI adduct with PANI and distributed onto surface of HPC in HPC/PDMcT–PANI composite. X-ray diffraction (XRD) revealed that the interconnected nanoporous structure of HPC and formation of PDMcT–PANI adduct significantly influenced the crystal growth and orientation of PDMcT. As confirmed by the cyclic voltammetry and galvanostatic charge–discharge tests, the incorporation of HPC and PANI had significantly improved the electrochemical performance of PDMcT. It was found that the initial discharge capacity of HPC/PDMcT–PANI composite reached 310 mAh g−1 and its specific capacity remained 150 mAh g−1 after 20 cycles. Moreover, the HPC/PDMcT–PANI composite also showed higher specific capacity and better cycling stability than that of its two binary composites [PDMcT–PANI (291 mAh g−1) or HPC/PDMcT (253 mAh g−1)].
Co-reporter:Ping Fu, Han Li, Jun Sun, Zhu Yi, Geng-chao Wang
Progress in Organic Coatings 2013 Volume 76(Issue 4) pp:589-595
Publication Date(Web):April 2013
DOI:10.1016/j.porgcoat.2012.11.014
Well-dispersible aniline/p-phenylenediamine copolymer [P(ANI-co-p-PDA)-F] was synthesized by chemical oxidative polymerization in the presence of nonylphenol ethoxylate (TX-8) with the hydrophilic lipophilic balance (HLB) value of 10–11. The FTIR and 1H NMR spectra proved that there was TX-8 composition in P(ANI-co-p-PDA)-F copolymer. And the P(ANI-co-p-PDA)-F had the smaller particle diameter and better dispersion stability in toluene than that of P(ANI-co-p-PDA) copolymer without TX-8. The anti-corrosion performance of carbon steel samples coated by P(ANI-co-p-PDA)-F/epoxy composite coatings in 5 wt% NaCl and 0.1 M HCl aqueous solution were evaluated by the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the P(ANI-co-p-PDA)-F/epoxy coatings on carbon steel possessed good corrosion resistance, and composite coating containing 7 wt% P(ANI-co-p-PDA)-F exhibited best anti-corrosive performance.Highlights► P(ANI-co-p-PDA)-F was synthesized in the presence of nonylphenol ethoxylate. ► P(ANI-co-p-PDA)-F had better dispersion than that of copolymer without surfactant. ► P(ANI-co-p-PDA)-F/epoxy coatings on carbon steel possessed good corrosion resistance.
Co-reporter:Biao Ma, Xiao Zhou, Hua Bao, Xingwei Li, Gengchao Wang
Journal of Power Sources 2012 Volume 215() pp:36-42
Publication Date(Web):1 October 2012
DOI:10.1016/j.jpowsour.2012.04.083
Hierarchical composites of sulfonated graphene-supported vertically aligned polyaniline nanorods (sGNS/PANI) are successfully synthesized via interfacial polymerization of aniline monomers in the presence of sulfonated graphene nanosheets (sGNS). The FE-SEM images indicate that the morphologies of sGNS/PANI composites can be controlled by adjusting the concentration of aniline monomers. FTIR and Raman spectra reveal that aligned PANI nanorod arrays for sGNS/PANI exhibit higher degree of conjugation compared with pristine PANI nanorods. The hierarchical composite based on the two-electrode cell possesses higher specific capacitance (497 F g−1 at 0.2 A g−1), better rate capability and cycling stability (5.7% capacitance loss after 2000 cycles) than those of pristine PANI nanorods.Graphical abstractHighlights► The composites of sGNS-supported vertically aligned PANI nanorods are obtained. ► The microstructure of composites can be controlled by the concentration of aniline. ► The composites with hierarchical structure show superior electrochemical performance.
Co-reporter:Minqiang Sun, Gengchao Wang, Xingwei Li, Qilin Cheng, and Chunzhong Li
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 10) pp:3981-3987
Publication Date(Web):February 22, 2012
DOI:10.1021/ie202384u
The novel hierarchical PANI/sMWCNT nanocomposites were synthesized through the interfacial polymerization method in the presence of the sulfonated multiwalled carbon nanotubes (sMWCNT), and the effect of oxidant content on the chain structure of PANI, the microstructure, and supercapacitive performance of the composites were investigated systematically. FT-IR spectra revealed the presence of π–π interactions between PANI and sMWCNT, and the charge-transfer composites were formed. It was found that more charge-transfer composites developed when the oxidant was at a lower content. The FESEM images indicated that the morphology of the composites changed significantly with varying oxidant content. It could be seen from electrochemical tests that the supercapacitive performance of the nanocomposites was influenced markedly by their microstructure, the content, and the oxidation degree of PANI. When the oxidant content was high at 2 for the APS/aniline mole ratio, the composite had high specific capacitance with 431.3 F/g but showed poor rate performance and charge/discharge stability. At a lower oxidant content with 1/6 of the APS/aniline mole ratio, the specific capacitance of the composite decreased to 216.6 F/g; nevertheless, it possessed superior rate performance with 82.8% capacitance retention at 10 A/g and excellent cyclability with just 11.2% capacitance loss after 2000 cycles.
Co-reporter:Zhong-ze Zhu, Geng-chao Wang, Min-qiang Sun, Xing-wei Li, Chun-zhong Li
Electrochimica Acta 2011 Volume 56(Issue 3) pp:1366-1372
Publication Date(Web):1 January 2011
DOI:10.1016/j.electacta.2010.10.070
The novel composites of sulfonated multi-walled carbon nanotubes (sMWCNTs) modified polyaniline (PANI) nanorods (PANI/sMWCNTs) were synthesized successfully by in situ oxidative polymerization method in the HClO4 solution. FTIR and Raman spectra revealed the presence of π–π interaction between the PANI and the sulfonated carbon nanotubes and the formation of charge transfer composites. It was found that the specific capacitance of the PANI/sMWCNT composites was markedly influenced by their morphological structure and the content of PANI which was coated onto the sMWCNT. The specific capacitance of the PANI/sMWCNT composite exhibited a maximum value of 515.2 F g−1 at the 76.4 wt% PANI. The charge–discharge tests showed the PANI/sMWCNT composites possessed a good cycling stability (below 10% capacity loss after 1000 cycles) compared to PANI nanorods.
Co-reporter:Liangbin Li, Yanhua Sun, Hua Bao, Xingwei Li, Gengchao Wang
European Polymer Journal 2011 Volume 47(Issue 8) pp:1630-1635
Publication Date(Web):August 2011
DOI:10.1016/j.eurpolymj.2011.05.014
Di-isocyanate-modified graphite oxide (iGO) was obtained by surface grafting of graphite oxide with toluene diisocyanate. A hybrid of iGO with 5-amino-1,4-dihydrobenzo[d]-1′,2′-dithiadiene (DTAn)/aniline (An) copolymer [P(DTAn-co-An)] was synthesized by a grafting technique. The reaction between the –NH2 groups of the P(DTAn-co-An) and the –NCO groups of the iGO was proved by Fourier-transform infrared spectra. The X-ray diffraction and transmission electron microscopy showed that the lamellar structure of the hybrid was destroyed and the nanofiber-like P(DTAn-co-An) was deposited on the surface of the iGO nanosheets. Compared to the P(DTAn-co-An), the electrochemical cycling stability of the hybrid was significantly improved due to the covalent interaction between the P(DTAn-co-An) and the iGO.
Co-reporter:Lifeng Jin;Xingwei Li;Liangbin Li
Journal of Applied Electrochemistry 2011 Volume 41( Issue 4) pp:377-382
Publication Date(Web):2011 April
DOI:10.1007/s10800-010-0246-z
Poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT)/sulfonated graphene conductive composite (PDMcT/SGS) was synthesized through in situ oxidative polymerization in the presence of the water-soluble sulfonated graphene sheets (SGS). Raman spectra revealed the existence of the π–π interaction between thiadiazole rings and basal planes of SGS. Scanning electron microscopy and transmission electron microscopy showed that the submicron-sized petals and nanofibers of PDMcT grew onto the surface of SGS. As evidenced by the cyclic voltammetry results, the incorporation of SGS has significantly improved the electrochemical activity and cyclability of PDMcT. The discharge capacity of PDMcT/SGS composite, measured with the charge–discharge tests, was 268 mAh g−1 at the first cycle and 124 mAh g−1 after 10 cycles.
Co-reporter:Xiao-feng Yang, Geng-chao Wang, Rui-yu Wang, Xing-wei Li
Electrochimica Acta 2010 Volume 55(Issue 19) pp:5414-5419
Publication Date(Web):30 July 2010
DOI:10.1016/j.electacta.2010.04.067
A novel layered manganese oxide/poly(aniline-co-o-anisidine) nanocomposite [MnO2/P(An-co-oAs)] was successfully synthesized by a delamination/reassembling process using P(An-co-oAs) ionomer and layered manganese oxide in aqueous solution. This nanocomposite obtained was then characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), electron microscopy (SEM), and thermogravimetric (TG) analysis. X-ray diffraction and electron microscope analysis showed that the MnO2/P(An-co-oAs) nanocomposite had a lamellar structure with increasing interlayer spacing. The MnO2/P(An-co-oAs) nanocomposite exhibited substantially improved conductivity, which was near 100 times greater than that of its pristine MnO2 (3.5 × 10−7 S cm−1). The specific capacitance of the MnO2/P(An-co-oAs) nanocomposite reached 262 F g−1 in 1 M Na2SO4 at a current density of 1 A g−1, which was significantly higher than that of either of its two pristine materials [MnO2 (182 F g−1) or P(An-co-oAs) (127 F g−1)] owing to the synergic effect between the two pristine components. The fabrication mechanism of the nanocomposite was also proposed and discussed in this paper.
Co-reporter:Gengchao Wang, Lifeng Jin, Jiankun Ye, Xingwei Li
Materials Chemistry and Physics 2010 Volume 122(Issue 1) pp:224-229
Publication Date(Web):1 July 2010
DOI:10.1016/j.matchemphys.2010.02.038
Poly(2,5-dimercapto-1,3,4-thiadiazole-polyaniline) adduct (PDMcT-PANI) was synthesized by chemical oxidative polymerization. It indicates that electrons are transferred between the PANI and the PDMcT to form the electron donor-acceptor adduct. PDMcT-PANI intercalated graphite oxide composites (PDMcT-PANI/GO) were synthesized by delamination/reassembling method. The hydrogen bond is formed between the –NH and –SH groups of PDMcT-PANI and the carboxyl groups at the edges of the GO, which is confirmed by FTIR. XRD and TEM results show that the PDMcT-PANI/GO composites still maintain good lamellar structure after intercalation, and the interlayer spacing (Ic values) of the GO is enlarged with the addition of the PDMcT-PANI. PDMcT-PANI/GO composites provide better thermal stability compared with pristine GO and PDMcT-PANI. In addition, the intercalation of PDMcT-PANI also improves the electrical conductivity and electrochemical properties of the composites.
Co-reporter:Gengchao Wang;Xiaofeng Yang;Yanhua Sun;Hua Bao ;Xingwei Li
Macromolecular Chemistry and Physics 2009 Volume 210( Issue 24) pp:2118-2124
Publication Date(Web):
DOI:10.1002/macp.200900324
Co-reporter:Bin Yao;Xingwei Li ;Zhiping Zhang
Journal of Applied Polymer Science 2009 Volume 112( Issue 4) pp:1988-1993
Publication Date(Web):
DOI:10.1002/app.29658
Abstract
Aniline/p-phenylenediamine copolymer [poly(ANI-co-p-PDA)] was prepared by chemical oxidative polymerization. FTIR and 1H-NMR analysis indicate that the poly(ANI-co-p-PDA) is oligomer with end-capped amino groups, which can cure epoxy resin. The anticorrosion performance of carbon steel (CS) samples coated by epoxy resin coating cured with poly(ANI-co-p-PDA) and epoxy resin coating cured with triethylenetetramine exposed to 5 wt % NaCl and 0.1 mol/L HCl aqueous solution is studied by the potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that the CS coated by epoxy resin coating cured with poly (ANI-co-p-PDA) has more excellent corrosion protection than that of epoxy resin coating cured with triethylenetetramine. Raman spectroscopy analysis indicates that the surface of CS coated by epoxy resin coating cured with poly(ANI-co-p-PDA) forms passive layer, which is composed of α-Fe2O3. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Gengchao Wang, Jing Zhao, Xingwei Li, Chunzhong Li, Weikang Yuan
Synthetic Metals 2009 Volume 159(5–6) pp:366-371
Publication Date(Web):March 2009
DOI:10.1016/j.synthmet.2008.10.005
Poly(N-[5-(8-hydroxyquinoline)methyl]aniline)-intercalated vanadium pentoxide xerogel hybrids (PNQA/V2O5) were synthesized by in situ intercalative polymerization method. The results showed that the V2O5 maintains lamellar structure, but its interlayer spacing had increased from 1.18 to 1.76 nm. The electrical conductivity of the freshly prepared PNQA/V2O5 hybrid was 2 orders of magnitude higher than that of V2O5 xerogel. It was found that the aging in air facilitated the chain growth of PNQA between the V2O5 lamella, resulting in the increase in the electrical conductivity. The fluorescent analysis indicated that the emission band of the hybrid was red-shifted 19 nm in comparison with pure PNQA, and the quantum yield of the PNQA/V2O5 hybrids is 2–3 times higher than that of PNQA in ethanol.
Co-reporter:Gengchao Wang, Yunli Ding, Fei Wang, Xingwei Li, Chunzhong Li
Journal of Colloid and Interface Science 2008 Volume 317(Issue 1) pp:199-205
Publication Date(Web):1 January 2008
DOI:10.1016/j.jcis.2007.09.033
Poly(aniline-2-sulfonic acid) (PASA)-modified multiwalled carbon nanotubes (MWNTs) were prepared by in situ oxidative polymerization. HRTEM images show that the PASA-modified MWNTs (PASANTs) are core (MWNT)–shell (PASA) tubular structures with a shell thickness of several nanometers. The strong interaction between the surface of the MWNTs and the conjugated structure of the PASA shell layer was proven by FTIR spectra. It was found that the aqueous dispersibility and dispersion stability of PASANTs were significantly improved compared to those of the raw MWNTs. Furthermore, when the PASA content is greater than 30 wt%, no precipitation is found for the dispersions of modified MWNTs after sedimentation for 500 h, exhibiting an excellent stability. The electrical conductivity of these modified MWNTs is 2–5 times higher than that of raw MWNTs and is 103 times higher than that of PASA.The aqueous dispersability of the MWNTs is evidently improved after modification with PASA.
Co-reporter:Chang Su;Farong Huang ;Xingwei Li
Polymer Composites 2008 Volume 29( Issue 10) pp:1177-1182
Publication Date(Web):
DOI:10.1002/pc.20490
Abstract
The melt-processable polyaniline nanofibers doped with superfluous dodecylbenzenesulfonic acid (PANI-DBSA) were synthesized using the interfacial polymerization and thermal doping technique. Conducting composites composed of PANI-DBSA nanofibers, low-density polyethylene (LDPE), and ethylene-acrylic acid copolymer (EAA) as compatibilizer were prepared by melt processing. The effects of PANI-DBSA nanofibers on the electrical conductivity, and mechanical properties, and morphological structure of the composites were investigated. As a result, the conducting composites had lower percolation threshold (4 wt%) due to the easy formation of conducting paths for fibrillar-like PANI-DBSA in the LDPE matrix, which was also confirmed by the frequency dependence of the real part of the AC conductivity. The Scanning electron microscopy (SEM) images indicated that the PANI-DBSA nanofibers were dispersed uniformly in the matrix. The mechanical properties of the composites were improved at the low PANI-DBSA load (about 1 wt%), but they were deteriorated at high PANI-DBSA content. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Co-reporter:Bin Yao, Gengchao Wang, Jiankun Ye, Xingwei Li
Materials Letters 2008 Volume 62(12–13) pp:1775-1778
Publication Date(Web):30 April 2008
DOI:10.1016/j.matlet.2007.10.001
Uniform polyaniline (PANI) nanofibers were synthesized by interfacial polymerization. Transmission electron microscopy (TEM) image shows that the nanofibers have average diameter of 30–60 nm and length of 200–400 nm. And the PANI nanofibers have the good dispersion stability in the ethanol. The anti-corrosion performance of PANI nanofibers and aggregated PANI-coated carbon steel samples exposed to 5% NaCl aqueous solution was evaluated by electrochemical corrosion measurements. The results show that the carbon steel coated with PANI nanofibers has more excellent corrosion protection than that with aggregated PANI. Raman spectroscopy analysis indicates that the surface of carbon steel coated with PANI nanofibers formed better passive layer, which is composed of α-Fe2O3 and Fe3O4.
Co-reporter:Chang Su;Farong Huang
Journal of Applied Polymer Science 2007 Volume 106(Issue 6) pp:4241-4247
Publication Date(Web):7 SEP 2007
DOI:10.1002/app.26985
Composites of polyaniline (PANI) nanorods and multiwalled carbon nanotubes (MWNTs) coated with PANI were prepared by in situ polymerization with perchloric acid as a dopant. Transmission electron microscopy images showed that the coexisting composites of PANI nanorods and MWNTs coated with PANI were formed at low MWNT contents. The interaction between MWNTs and PANI was proved by Fourier transform infrared and ultraviolet–visible spectra. The electrical conductivity of a dedoped PANI/MWNT composite with a 16.3 wt % concentration of MWNTs reached 3.0 × 10−3 S/cm, which was 6 orders of magnitude higher than that of dedoped PANInanorods. The results also showed that coexisting composites of PANI nanorods and MWNTs coated with PANI had high electrochemical activity and good cyclic stability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Co-reporter:Jing Zhao;Xingwei Li;Chunzhong Li
Journal of Applied Polymer Science 2007 Volume 103(Issue 4) pp:2569-2574
Publication Date(Web):27 NOV 2006
DOI:10.1002/app.25141
Poly(N-propane sulfonic acid aniline) (PSPAN) can be formed between the lamellas of V2O5 xerogel by in situ oxidative polymerization/intercalation of N-propane sulfonic acid aniline in the presence of air (V2O5 being the oxidation agent). The PSPAN/V2O5 nanocomposites were characterized by XRD, TEM, TGA, FTIR, UV–vis-NIR, and conductivity measurement. The results show that the V2O5 maintains lamellar structure, but its interlayer spacing has increased from 1.18 to 1.31 nm. The FTIR spectra indicate that there is interaction between negatively charged oxygen of the sulfonic group of PASPN and the vanadium ion in V2O5 matrix. The electrical conductivity of PSPAN/V2O5 nanocomposite reached the value of 1.2 × 10−2 S/cm, which is 104 times higher than that of the V2O5 xerogel, and is 102 times more than that of the PSPAN. It was found that the aging in air facilitated the chain growth of PSPAN between the V2O5 lamellas, resulting in the increase of the electrical conductivity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2569–2574, 2007
Co-reporter:Gengchao Wang;Xingwei Li;Zhongyuan Shen;Chunzhong Li
Journal of Applied Polymer Science 2005 Volume 98(Issue 4) pp:1511-1516
Publication Date(Web):30 AUG 2005
DOI:10.1002/app.21972
Conducting composites of aniline/o-anisidine copolymer doped by dodecylbenzenesulfonic acid (P(An-co-oAs)-DBSA), linear low-density polyethylene (LLDPE), and ethylene–acrylic acid copolymer (EAA) as compatibilizer were prepared by melt processing. The effects of composition on electrical conductivity, resistivity-temperature characteristic, and mechanical properties were also investigated. The electrical conductivity of ternary composites markedly increased due to compatibilizition and protonation effect of the EAA. The SEM micrograph shows that the compatibility between the P(An-co-oAs)-DBSA and the LLDPE matrix is enhanced after the introduction of EAA. The positive temperature coefficient of resistivity characteristic is observed. Tensile strength of P(An-co-oAs)-DBSA/LLDPE/EAA composites is improved, compared with P(An-co-oAs)-DBSA/LLDPE composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1511–1516, 2005
Co-reporter:Xi Wang, Chongyang Yang and Gengchao Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 38) pp:NaN14848-14848
Publication Date(Web):2016/08/26
DOI:10.1039/C6TA05299A
Stretchable electrolytes are the key components to fabricate high-performance stretchable/flexible energy-storage devices, but there is little related research, especially about organic solvent-resistant types. Herein, novel stretchable fluoroelastomer/tetraethylammonium tetrafluoroborate–acetonitrile (FKM/Et4NBF4–AN), quasi-solid-state organic electrolytes were prepared by chemical cross-linking with hexamethylene diamine (HMDA). The FKM/Et4NBF4–AN quasi-solid-state electrolyte exhibited a slight plastic deformation (1.4%) after 500 stretching cycles at 100% strain, good solvent resistance, high ionic conductivity (9.9 × 10−3 S cm−1), and nonflammability. In order to demonstrate its superior performance, a novel “prestrain-stick-relax-cure-soak” assembly strategy was adopted for the organic asymmetric flexible supercapacitors (oAFSCs) with carbon nanotube paper-supported polypyrrole (CNT@PPy) and poly(1,5-diaminoanthraquinone) (CNT@PDAA) as cathode and anode, respectively. The as-assembled oAFSC achieved a high energy density of 58.2 W h kg−1 (4.87 mW h cm−3) at a power density of 0.37 kW kg−1 (0.031 W cm−3), superior cycling stability (88% retention after 10000) and works well even in the stretched, bended or twisted state.
Co-reporter:Minqiang Sun, Gengchao Wang, Chongyang Yang, Hao Jiang and Chunzhong Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 7) pp:NaN3890-3890
Publication Date(Web):2015/01/02
DOI:10.1039/C4TA06728B
Supercapacitors based on π-conjugated conducting polymers have attracted attention due to their high pseudo-capacitance characteristics. However, the narrow window of their potential (<1 V) gives rise to low energy density, and this restricts their practical application. In the present study a novel hierarchical nanocomposite, graphene nanosheets/acid-treated multi-walled carbon nanotube-supported poly(1,5-diaminoanthraquinone) (GNS/aMWCNT@PDAA), has been successfully synthesized using cerium sulphate (Ce(SO4)2) as oxidant and camphor sulphonic acid as dopant. The nanocomposite exhibits a unique nanoporous morphology, a high π-conjugated degree and an excellent conductive interpenetrating network. With these intriguing features, in addition to its unique p- and n-doping characteristics, the supercapacitor in a 1 M tetraethylammonium tetrafluoroborate -acetonitrile (Et4NBF4-AN) electrolyte can be reversibly cycled within a potential window of 2.8 V. The supercapacitor achieves a high energy density of 86.4 W h kg−1 at a power density of 0.73 kW kg−1, and still retains energy density of 55.5 W h kg−1 at a power density of 153.9 kW kg−1. In addition, superior cycling stability is achieved, with only 7% capacitance loss after 10000 cycles. This excellent performance surpasses that of other recently reported supercapacitors and represents a significant breakthrough in π-conjugated polymer-based supercapacitors.
Co-reporter:Shuangmin Yu, Fan Qin and Gengchao Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 7) pp:NaN1510-1510
Publication Date(Web):2016/01/04
DOI:10.1039/C5TC04026D
The introduction of conductive polymers can significantly improve the dielectric constant of polymer-based materials but results in overly large increases of dielectric loss. Herein, uniform-sized and easily dispersed polyaniline nanorods (dPANI@PVP) were synthesized by applying a dynamically interfacial polymerization method and encapsulating the nanorods with poly(vinyl pyrrolidone) (PVP). The synthesized dPANI@PVP was then used to fabricate poly(vinylidene fluoride)-based (PVDF) nanocomposites that displayed a high dielectric constant and low dielectric loss. Morphological and structural analyses showed the insulating PVP shell to have a thickness of 5–10 nm and to be wrapped on the dPANI nanorod surface, which not only provided a barrier layer between the conductive dPANI nanorods, but also facilitated an excellent dispersion of dPANI nanorods in the PVDF matrix. As a result, the dPANI@PVP/PVDF nanocomposites showed a relatively low dielectric loss while maintaining a sufficiently high dielectric constant. Specifically, when the loading of dPANI@PVP was 9.5 wt%, the dielectric constant of the nanocomposite reached 174 at 100 Hz, which is about 20 times higher than that of pure PVDF. Moreover, there was only a small increase of the dielectric loss from 0.06 for pure PVDF to 0.17 for the nanocomposite.
Co-reporter:Qianqiu Tang, Wenqiang Wang and Gengchao Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 12) pp:NaN6670-6670
Publication Date(Web):2015/02/16
DOI:10.1039/C5TA00328H
The real-world applications of supercapacitors are hindered by their relatively low energy density compared with rechargeable batteries. Even with tremendous efforts in developing cathodes for aqueous asymmetric supercapacitors (AASCs), their supercapacitive performance is still severely restricted by the low specific capacitance of anodes which mostly consist of carbonaceous materials. We developed a novel low-cost anode of homogenous Fe2O3 nanowires grown on carbon fiber paper (CFP) that achieves a high specific capacitance of 908 F g−1 at 2 A g−1 and excellent rate performance (90% capacitance retention up to 10 A g−1) in a wide negative potential window of 0 to −1.35 V. Such an excellent supercapacitive performance makes it a perfect anode compared with other reported ones. Matching it with the NiO nanoflake cathode (1520 F g−1 at 2 A g−1 in 0–0.45 V) on CFP, an extremely high energy density of 105 W h kg−1 is obtained at a power density of 1400 W kg−1 and still retains 72.6 W h kg−1 at 12700 W kg−1 for the AASCs, which is much superior to previously reported AASCs and even exceeding those of Ni-MH batteries.
Co-reporter:Chongyang Yang, Jiali Shen, Chunyan Wang, Haojie Fei, Hua Bao and Gengchao Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 5) pp:NaN1464-1464
Publication Date(Web):2013/11/07
DOI:10.1039/C3TA13953K
Sandwich-like reduced graphene oxide/carboxylated multi-walled carbon nanotube (RGO/cMWCNT) hybrid film and the carbon fiber paper-supported polypyrrole (CFP/PPy) composite film were prepared by a vacuum-infiltration process and an electrochemical deposition method, respectively. Furthermore, a novel all-solid-state asymmetric supercapacitor (ASC) was fabricated using RGO/cMWCNT as the negative electrode and CFP/PPy as the positive electrode, separated with potassium polyacrylate/KCl gel electrolyte. Due to the unique structure, stable potential window and good capacitive performance of the two electrodes, the as-fabricated ASC can be cycled reversibly at a cell voltage of 1.6 V and displays outstanding performances with an energy density of 28.6 W h kg−1 and a power density of 15.1 kW kg−1. Additionally, our ASC device also presents a superior long cycle life with 93% capacitance retention after 2000 cycles.
Co-reporter:Han Li, Minqiang Sun, Tao Zhang, Yuqian Fang and Gengchao Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 43) pp:NaN18352-18352
Publication Date(Web):2014/09/04
DOI:10.1039/C4TA03366C
A novel PEDOT-PSS coated sulfur@activated porous graphene composite (PEDOT/S@aPG) is prepared by the impregnation of sulfur with aPG and encapsulation with PEDOT-PSS as the cathode material for lithium–sulfur batteries. The abundant nanopores and large surface area of aPG can provide an intimate contact and strong interaction with S species. Furthermore, the conductive PEDOT-PSS layer can facilitate the charge transportation and prevent the dissolution of polysulfides. As a result, the as-prepared PEDOT/S@aPG composite cathode with a sulfur content of about 60.1% shows a higher specific discharge capacity (1198 mA h g−1 at 0.1 C) in the first cycle and good cycling stability, retaining a reversible capacity of 845 mA h g−1 after 200 cycles. Moreover, the PEDOT/S@aPG cathode also exhibits excellent rate capability, showing a high reversible capacity of 718 mA h g−1 at 2 C.
![2-?Propenoic acid, 2-?hydroxyethyl ester, polymer with 3-?hydroxy-?2-?(hydroxymethyl)?-?2-?methylpropanoic acid, 1,?1'-?methylenebis[4-?isocyanatocyclohexan?e]?, 2-?methyloxirane, oxirane and 2-?propenamide, compd. with N,?N-?dibutyl-?1-?butanamine](/data/chemimg/3781100/1700632-69-4.png)
![2-?Propenoic acid, 2-?hydroxyethyl ester, polymer with 3-?hydroxy-?2-?(hydroxymethyl)?-?2-?methylpropanoic acid, 1,?1'-?methylenebis[4-?isocyanatocyclohexan?e]?, 2-?methyloxirane, oxirane and 2-?propenamide, compd. with N,?N-?dibutyl-?1-?butanamine](/data/chemimg/3781100/1700632-69-4_b.png)
