27 results on '"Cao, Dianxue"'
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2. Simultaneously morphology and phase controlled synthesis of cobalt manganese hydroxides/reduced graphene oxide for high performance supercapacitor electrodes.
- Author
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Bai, Xue, Cao, Dianxue, and Zhang, Hongyu
- Subjects
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SUPERCAPACITOR electrodes , *COBALT hydroxides , *ELECTRODE performance , *SUPERCAPACITOR performance , *ENERGY storage , *GRAPHENE oxide - Abstract
Cobalt manganese hydroxides with well-defined nanowire morphology (CoMn-HW) is scalable fabricated by adjusting solution contents, Mn/Co ratio and alkaline species. To further improve the conductivity of CoMn-HW, GO is introduced during fabrication process and reduced to rGO according to the high temperature and alkali atmosphere. By optimizing the adding mass of rGO, CoMn-HW/rGO with sandwiched like structure is successfully synthesized for supercapacitor electrode. The composite delivers a high specific capacitance of 784 F g−1 at current density of 0.5 A g−1, good rate capability (84.2% capacitance retention after current density increase 10 times). Moreover, an asymmetric supercapacitor with CoMn-HW/rGO10 as the positive electrode and active carbon as the negative electrode, is assembled and delivers a maximum energy density of 38.3 Wh kg−1 and power density of 8000 W kg−1, representing its potential in energy storage and conversion systems. • Co, Mn-hydroxides with nanowire morphology is scalable fabricated. • CoMn-HW/rGO with sandwiched like structure is synthesized under optimal synthesis condition. • An asymmetric supercapacitor based on CoMn-HW/rGO and AC is assembled with high energy and power densities. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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3. Creating oxygen-vacancies in MoO3-x nanobelts toward high volumetric energy-density asymmetric supercapacitors with long lifespan.
- Author
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Yang, Jiao, Xiao, Xu, Chen, Peng, Zhu, Kai, Cheng, Kui, Ye, Ke, Wang, Guiling, Cao, Dianxue, and Yan, Jun
- Abstract
Abstract Herein, we present the synthesis of oxygen vacancies-rich α -MoO 3- x nanobelts through a novel defect-engineering strategy. The oxygen-vacancies could not only greatly increase the interlayer spacing and the electrical conductivity of MoO 3 , but also significantly enhance the electrochemical activity, which promotes faster charge storage kinetics. Meanwhile, to further facilitate the electron transfer and ion transport, a graphene nanomesh-carbon nanotube/MoO 3- x (GC/MoO 3- x) nanocomposite with three-dimensional sandwiched structure was fabricated, which displays high specific capacity up to 306 C g
−1 as well as high volumetric capacity of 692 C cm−3 . Our fabricated asymmetric supercapacitor (ASC) with the GC/MoO 3- x and GC/MnO 2 nanocomposites as anode and cathode, respectively, exhibits an ultrahigh energy of 150 Wh kg−1 , corresponding to an impressive volumetric energy density of 319 Wh L−1 . Notably, both the gravimetric and volumetric energy densities are much higher than most of the previously reported metal oxide based ASCs in aqueous electrolytes. Furthermore, the ASC displays an ultra-long lifespan with 101% retention ratio after 30,000 cycles. The outstanding performances of GC/MoO 3- x composite render it a highly promising candidate for next-generation supercapacitors with both high energy and power densities in future applications, especially in greatly limited space. Graphical abstract fx1 Highlights • Oxygen vacancies-rich MoO 3- x is prepared through a novel defect-engineering strategy. • Oxygen-vacancies greatly increase the interlayer spacing, electrical conductivity and electrochemical activity of MoO 3. • High specific capacity up to 306 C g−1 (692 C cm−3 ) is obtained. • An ultrahigh volumetric energy density of 319 Wh L−1 is obtained, the highest value for aqueous supercapacitors up to date. • ASC displays an ultra-long lifespan with 101% retention ratio after 30,000 cycles. [ABSTRACT FROM AUTHOR]- Published
- 2019
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4. Polydopamine‐Modified Reduced Graphene Oxides as a Capable Electrode for High‐Performance Supercapacitor.
- Author
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Dong, Shu, Xie, Zeyu, Fang, Yongzheng, Zhu, Kai, Gao, Yinyi, Wang, Guiling, Yan, Jun, Cheng, Kui, Ye, Ke, and Cao, Dianxue
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DOPAMINE ,GRAPHENE oxide ,SUPERCAPACITOR electrodes - Abstract
Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. As‐prepared PDA‐rGO shows a capable electrochemical performance as an electrode material for supercapacitors. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. Meanwhile, the rGO with high conductivity promise fast electronic transport. Polydopamine modified reduced graphene oxides (PDA‐rGO) are synthesized by a facile dopamine polymerization reaction. A capacitance of 120 F g−1 is achieved at current density of 2 A g−1. PDA‐rGO also presents a superior cycling performance with capacitance retention of ∼99% after 10000 cycles. The remarkable electrochemical performance is attributed to the addition of PDA, which prevents the stacking of rGO and enhances the wettability of composite. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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5. Ultrahigh energy density battery-type asymmetric supercapacitors: NiMoO4 nanorod-decorated graphene and graphene/Fe2O3 quantum dots.
- Author
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Yang, Jiao, Liu, Wei, Niu, Hao, Cheng, Kui, Ye, Ke, Zhu, Kai, Wang, Guiling, Cao, Dianxue, and Yan, Jun
- Abstract
NiMoO
4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets (G-NiMoO4 ) are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g−1 at 1 A·g−1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g−1 . An asymmetric supercapacitor (ASC) fabricated with the G-NiMoO4 composite as the positive electrode and Fe2 O3 quantum dot-decorated graphene (G-Fe2 O3 -QDs) as the negative electrode delivers an ultrahigh energy density of 130 Wh·kg−1 , which is comparable to those of previously reported aqueous NiMoO4 -based ASCs. Even when the power density reaches 33.6 kW·kg−1 , an energy density of 56 Wh·kg−1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes.[ABSTRACT FROM AUTHOR]
- Published
- 2018
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6. Two-Dimensional Titanium Carbide MXene as a Capacitor-Type Electrode for Rechargeable Aqueous Li-Ion and Na-Ion Capacitor Batteries.
- Author
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Zhu, Kai, Zhang, Hongyu, Ye, Ke, Zhao, Wenbin, Yan, Jun, Cheng, Kui, Wang, Guiling, Yang, Baofeng, and Cao, Dianxue
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TITANIUM carbide ,ALKALI metal ions ,ELECTRODES ,LITHIUM-ion batteries ,SODIUM ions - Abstract
To bridge the gap of the alkali-metal-ion (Li or Na) batteries and supercapacitors, hybrid devices called capacitor batteries are being designed, which are adaptive for large-scale energy-storage systems. Two-dimensional transition-metal carbide materials (MXene) with high electronic conductivities have become capable electrode materials for supercapacitors. Herein, Ti
3 C2 Tx synthesized by selectively etching the Al layer from the Ti3 AlC2 presents a remarkable electrochemical performance as an electrode material for the supercapacitor with Li2 SO4 or Na2 SO4 aqueous electrolyte. It displays a capacitance of 243 F g−1 at a low current density of 100 mA g−1 with a capacitance retention of 95 % in the Li2 SO4 electrolyte, and a capacitance of 150 F g−1 at a low current density of 200 mA g−1 with a capacitance retention of 95 % in the Na2 SO4 electrolyte, which shows its potential application for capacitor batteries. Moreover, the LiMn2 O4 //Ti3 C2 Tx Li-ion capacitor battery and MnO2 //Ti3 C2 Tx Na-ion capacitor battery are designed and assembled for the first time. Such rechargeable aqueous capacitor batteries display capable capacities, remarkable rate abilities, and excellent cycling performances, which further demonstrates that Ti3 C2 Tx is an outstanding capacitor-type electrode material for capacitor batteries. [ABSTRACT FROM AUTHOR]- Published
- 2017
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7. Hydrothermal deposition of manganese dioxide nanosheets on electrodeposited graphene covered nickel foam as a high-performance electrode for supercapacitors.
- Author
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Li, Yiju, Cao, Dianxue, Wang, Ying, Yang, Sainan, Zhang, Dongming, Ye, Ke, Cheng, Kui, Yin, Jinling, Wang, Guiling, and Xu, Yang
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SUPERCAPACITORS , *MANGANESE dioxide electrodes , *ELECTROFORMING , *THERMAL analysis , *GRAPHENE , *NICKEL , *METAL foams - Abstract
In this paper, the graphene oxide nanosheets are simultaneously reduced and deposited on nickel foam (denoted as Ni-foam@GNS) by one step electrodeposition method. The interconnected crumpled graphene nanosheets grown on Ni foam serve as a three-dimensional (3D) conductive skeleton for hydrothermal deposition of MnO 2 nanosheets by in-situ redox reaction. The MnO 2 nanosheets anchored on the graphene covered nickel foam (denoted as Ni-foam@GNS@MnO 2 ) show unique 3D porous interconnected networks. The samples are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), N 2 adsorption–desorption measurements and fourier transform infrared spectroscopy (FT-IR). The capacitive performances are researched by cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). The results reveal that the Ni-foam@GNS@MnO 2 electrode exhibits a high specific capacitance of 462 F g −1 at 0.5 A g −1 and excellent capacitance retention of 93.1% after 5000 cycles at 10 A g −1 . Furthermore, the Ni-foam@GNS@MnO 2 electrode delivers a high energy density of 26.1 Wh kg −1 even at a high power density of 3981 W kg −1 . These results demonstrate that the Ni-foam@GNS@MnO 2 composite offers great promise in large-scale energy storage device applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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8. "Trunk-Leaf Vein" structure inspired synthesis of mesoporous Carbon@Nickel oxide/nickel ternary composite for sustainable supercapacitor electrode.
- Author
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Zhang, Hongyu, Cao, Dianxue, Jiang, Zhuwu, Yu, Hai, Shi, Antong, and Bai, Xue
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SUPERCAPACITOR electrodes , *NEGATIVE electrode , *ENERGY density , *ENERGY storage , *POTENTIAL energy , *VEINS - Abstract
[Display omitted] • OMC@NiO/Ni is synthesized via solvothermal reaction and subsequent calcination treatment. • "Trunk-leaf vein" structure endows OMC@NiO/Ni with superior electrochemical performance. • An asymmetric supercapacitor based on OMC@NiO/Ni and rGO/VO x as positive and negative electrodes respectively, is assembled. Supercapacitors are sustainable energy storage devices with the characteristics of high power density, long life span and ultrafast charge-discharge time. Herein, considering low conductivity of NiO and inspired by the "trunk-leaf vein" structure, mesoporous carbon and nickel dots are introduced into structure reacting as electron scaffold via facile hydrothermal and annealing procedures. Special hierarchical structure is obtained with oxygen modified mesoporous carbon (OMC) as core and NiO sheets as core accompanying with metallic nickel dots deposited on NiO sheets. Such "trunk-leaf vein" architecture can effectively ensure more active sites contacting with electrolyte, furthermore provide conductive scaffolds for electron transport. As expected, the OMC@NiO/Ni exhibits high specific capacitance of 651.3 F g−1 at 2 A g−1 and superior cycling life of 92.2% after 4000 cycles. Moreover, a novel negative electrode rGO/VO x is synthesized ascribe to the superior capacitance and life span. At last, an asymmetric device is assembled using OMC@NiO/Ni as positive electrode and rGO/VO x as negative electrode, which delivers maximum energy density of 44.3 Wh kg−1, high power density of 12,000 W kg−1 and excellent cycling life of 94.5% after 5000 cycles. The high performance of OMC@NiO/Ni renders it a potential material for energy storage-conversion equipments. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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9. Hierarchical copper cobalt sulfides nanowire arrays for high-performance asymmetric supercapacitors.
- Author
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Du, Jialiang, Yan, Qing, Li, Yiju, Cheng, Kui, Ye, Ke, Zhu, Kai, Yan, Jun, Cao, Dianxue, Zhang, Xianfa, and Wang, Guiling
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SUPERCAPACITOR electrodes , *COBALT sulfide , *COPPER sulfide , *ENERGY density , *METAL sulfides , *POWER density , *SILVER sulfide , *ACTIVATED carbon - Abstract
Binary transition metal sulfides are considered to be promising electrode materials for high-performance supercapacitors because of their ultrahigh electron conductivity and superior electrochemical activity compared to the unitary transition metal sulfides. In this work, copper cobalt sulfides nanowire arrays on nickel foam with different element ratios and porosities are prepared by using a two-step hydrothermal method, and their electrochemical performance is explored. Benefited from the high electrical conductivity, rich active sites and optimized microstructure, the optimized copper cobalt sulfides (CuCo 2 S 4) electrode can achieve a ultrahigh specific capacitance of 2446.6 F·g−1 at 1 A·g−1 and favorable rate performance. The asymmetric supercapacitor assembled with the CuCo 2 S 4 nanowire array and activated carbon (AC) electrodes displays a high energy density of 33.4 Wh·kg−1 at a power density of 751.5 W·kg−1 can be obtained. Additionally, the assembled asymmetric cell shows a favorable capacitance retention of 78% after charging and discharging for 10,000 cycles at a high current density of 4 A·g−1. • The CuCo 2 S 4 electrode achieves an ultrahigh specific capacitance of 2446 F·g−1 at 1 A·g−1. • The CuCo 2 S 4 electrode has unique microstructure and exhibits good rate performance. • The CuCo 2 S 4 /AC-ASC displays high energy density of 33.4 Wh·kg−1 at power density of 751.5 W·kg−1. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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10. Fe3O4 nanospheres in situ decorated graphene as high-performance anode for asymmetric supercapacitor with impressive energy density.
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Sheng, Shuang, Liu, Wei, Zhu, Kai, Cheng, Kui, Ye, Ke, Wang, Guiling, Cao, Dianxue, and Yan, Jun
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ANODES , *SUPERCAPACITORS , *GRAPHENE , *ENERGY density , *NANOCOMPOSITE materials - Abstract
Graphical abstract Abstract Unique nanostructure, high electrical conductivity, satisfactory energy density, and extraordinary cycling stability are important evaluation criteria for high-efficient energy storage devices. Herein, Fe 3 O 4 nanospheres are successfully in situ decorated on graphene nanosheets through an environmentally benign and facile solvothermal procedure. When utilized as an electrode for supercapacitor, the graphene/Fe 3 O 4 nanocomposite exhibits a notably enhanced specific capacity (268 F·g−1 at 2 mV·s−1) and remarkable cycling performance with 98.9% capacity retention after 10,000 cycles. Furthermore, the fabricated graphene/MnO 2 //graphene/Fe 3 O 4 asymmetric supercapacitor device displays a desirable energy density (87.6 Wh·kg−1) and superior cycling stability (93.1% capacity retention after 10,000 cycles). [ABSTRACT FROM AUTHOR]
- Published
- 2019
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11. Controllable one-pot synthesis of emerging β-Cu2Se nanowire freely standing on nickel foam for high electrochemical energy storage performance.
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Xu, Panpan, Wang, Guiling, Miao, Chenxu, Cheng, Kui, Ye, Ke, Zhu, Kai, Yan, Jun, Cao, Dianxue, and Zhang, Xianfa
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COPPER compounds , *NANOWIRES , *NICKEL , *METAL foams , *ELECTROCHEMISTRY , *ENERGY storage - Abstract
Graphical abstract The super-ionic conductivity nanowire Cu 2 Se/Ni-foam electrode processes excellent cycling performance and the electrode is firstly assembled to asymmetric supercapacitor achieving high energy and power density. Abstract Transition metal selenide has stimulated much research interest in energy storage and conversion, due to its excellent electrical conductivity. β-Cu 2 Se with special crystal structure is considered as super-ionic conductor, of which the diffusion coefficient is as large as a liquid. The fast ions and electrons conductor β-Cu 2 Se with uniformly dense nanowire crossing with each other directly on nickel foam is prepared via simple one-step solvothermal grow method for 4 h, avoiding conductive agent and binder. The feature much benefitting for electrons and ions transfer enable the β-Cu 2 Se-4h electrode delivers specific capacity as high as 182.4 mA h g−1 at current density of 2 mA cm−2, which is still 105.6 mA h g−1 even at high current density of 50 mA cm−2, and excellent cycling stability of 85% after repetitively charge-discharge 10,000 times. The fabricated asymmetric supercapacitor (β-Cu 2 Se-4h//AC) achieves maximum energy and power density is 48 Wh kg−1 and 5500 W kg−1. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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12. High-throughput fabrication of porous carbon by chemical foaming strategy for high performance supercapacitor.
- Author
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Ouyang, Tian, Zhang, Tianyu, Wang, Huizhong, Yang, Fan, Yan, Jun, Zhu, Kai, Ye, Ke, Wang, Guiling, Zhou, Limin, Cheng, Kui, and Cao, Dianxue
- Subjects
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ELECTROCHEMICAL sensors , *CARBON foams , *SUPERCAPACITORS , *PYROLYSIS , *POROUS materials - Abstract
Highlights • A gas foaming strategy is adopted to prepare the 3D hierarchical porous carbon. • NaHCO 3 is used as activator based on its multistep pyrolysis process. • The HPC shows high specific capacitance and outstanding stability. Abstract Inspired by people to make flour food, a one-pot, low-cost, green and environmental friendly gas foaming strategy is adopted here to prepare the three-dimensional hierarchical porous carbon (HPC) by introducing NaHCO 3 as foaming and activation agent. During the pyrolysis process, the CO 2 gas produced during the transforms from NaHCO 3 into Na 2 CO 3 will resulted in the producers of the macro-pores and meso-pores, meanwhile, the as-produced Na 2 CO 3 further reactor with the carbon intermediate at a high temperature, and finally result in forming a micro-pores porous structure. Such intimate structural interconnectivities provide three-dimensional continuous pathway for electron rapid transfer and the interconnected pores allow for the ion to penetrate and evenly contact the electrode material quickly. The electrochemical performance of HPC exhibits a high specific capacitance of 350 F g−1 at 1 A g−1 and outstanding electrochemical stability with capacitance retention up to 97% after 10,000 cycles. Moreover, the as-assembled symmetric supercapacitor exhibits an ultrahigh energy density of 27.4 Wh kg−1, much higher than most of carbon-based supercapacitors. These results demonstrate a straightforward environment friendly method to mass-produce economical, robust carbon materials as promising candidates for supercapacitor application. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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13. A double-chamber energy storage device with dual ionic electrolyte enabling high energy density.
- Author
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Guo, Fen, Fan, Baoan, Liu, Yi, Lu, Lilin, Lei, Yang, Cao, Dianxue, and Li, Yiju
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SUPERCAPACITORS , *FUEL cell design & construction , *POLYANILINES , *IONIC liquids , *ELECTROLYTE solutions , *ENERGY density ,DESIGN & construction - Abstract
In this work, for the first time, we design a high-energy-density double-chamber capacitor which consists of the cathode chamber (polyaniline@carbon fiber cloth electrode in HCl/FeCl 3 solution), anion-exchange membrane and the anode chamber (polyaniline@carbon fiber cloth electrode in HCl/FeCl 2 solution). Since the redox state of polyaniline can be continuously altered by the external potential during charging and discharging process, the addition of FeCl 3 (or FeCl 2 ) in the electrolyte works as chemical oxidant (or reductant) to oxidize (or reduce) the reduced (or oxidized) polyaniline to offer extended capacitance. Results show the double-chamber supercapacitor has a high area specific capacitance of 1.22 F cm −2 and an energy density of 108.44 μWh cm −2 , which are ∼3.5 times as large as those of the conventional single-chamber capacitor (0.35 F cm −2 / 31.11 μWh cm −2 ). This work demonstrates an innovative strategy by incorporating supercapacitor with fuel cell to improve the energy density. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. K2.25Ni0.55Co0.37Fe(CN)6 nanoparticle connected by cross-linked carbon nanotubes conductive skeletons for high-performance energy storage.
- Author
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Xu, Panpan, Wang, Guiling, Wang, Hengheng, Li, Yiju, Miao, Chenxu, Qu, Jun, Zhang, Yongcheng, Ren, Fangda, Cheng, Kui, Ye, Ke, Zhu, Kai, Cao, Dianxue, and Zhang, Xianfa
- Subjects
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PRUSSIAN blue , *COORDINATION compounds , *SUPERCAPACITORS , *ELECTRIC conductivity , *NANOPARTICLES , *CARBON nanotubes - Abstract
Prussian Blue (PB) coordination compound is a well-known ideal candidate for energy storage due to its tunable open framework structure. Especially transition metal hexacyanoferrate displays excellent performance in supercapacitor. In this paper, a facile one-step co-precipitation synthesis method is developed to prepare hybrid K 2.25 Ni 0.55 Co 0.37 Fe(CN) 6 /CNTs composite, aiming at increasing the electric conductivity of electrode material by introducing carbon nanotube conductive skeleton to the Cobale-Nickel hexacyanoferrate hybrid nanoparticles. The TEM image shows that K 2.25 Ni 0.55 Co 0.37 Fe(CN) 6 presents nanoparticles with a diameter about 20 nm, which are connected along the surface of carbon nanotube. Such special structure could facilitate the electric transportation between each nanoscale K 2.25 Ni 0.55 Co 0.37 Fe(CN) 6 particle, efficiently improving the utilization of active material. Considering the intrinsic abundant channels for ions insertion/extraction of nanoparticles and good conductivity of carbon nanotubes, our creative electrode is expected to display fantastic supercapacitor performance. The electrochemical data demonstrate that the K 2.25 Ni 0.55 Co 0.37 Fe(CN) 6 /CNTs electrode exhibits a high specific capacitance of 600 F g −1 at 0.2 A g −1 and excellent rate performance of 90.4% when the current density ranged from 0.2 A g −1 to 5 A g −1 . Furthermore, the K 2.25 Ni 0.55 Co 0.37 Fe(CN) 6 /CNTs composite achieves decent cycling stability with maintaining 94% of its initial specific capacitance after 2000 discharge/charge cycles. The excellent energy storage property offers a great promise as supercapacitor materials. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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15. Facile electrodepositing processed of RuO2-graphene nanosheets-CNT composites as a binder-free electrode for electrochemical supercapacitors.
- Author
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Kong, Shuying, Cheng, Kui, Ouyang, Tian, Gao, Yinyi, Ye, Ke, Wang, Guiling, and Cao, Dianxue
- Subjects
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SUPERCAPACITOR electrodes , *RUTHENIUM oxides , *ELECTROCHEMICAL electrodes , *GRAPHENE , *ELECTROPLATING , *CARBON fibers - Abstract
A unique nanostructure electrode consisting of RuO 2 nanoparticles with ultra-fine diameter (1.9 nm) anchored on the surface of graphene nanosheets (GNS) and carbon nanotube (CNT) is prepared as a binder-free supercapacitor electrode through two-step electrochemical routes. At first, free-standing GNS and CNT (GC) are directly deposited on the surface of carbon fiber cloth (CFC) to form a cross-linked composite via a cathodic electrophoretic deposition method. Safranin, a kind of cationic organic dye, is introduced in this stage as a new-type dispersant to disperse GNS and CNT in water to form a suspension solution. After the following electro-deposition process, the as-prepared GC composite is uniform covered with RuO 2 nanoparticles. Benefiting from the combined advantages of GNS, CNT and ultra-fine RuO 2 nanoparticles in such a binder-free structure, the hybrid electrode exhibits a high specific capacitance up to 480.3 F g −1 (based on the total mass of GNS, CNT and RuO 2 ) and remarkable cycling stability (89.4% capacitance retention after 10000 cycles). Furthermore, the assembled symmetric supercapacitor exhibits a high energy density of 30.9 Wh kg −1 and power density of 14000 W kg −1 with excellent stability performance (92.7% capacitance retention after 10000 cycles). Thus, the remarkable performance of the resultant RuO 2 electrode has provided a rational design strategy for developing supercapacitors with high energy density. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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16. Freestanding MnO2 nanoflakes on carbon nanotube covered nickel foam as a 3D binder-free supercapacitor electrode with high performance.
- Author
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Kong, Shuying, Cheng, Kui, Ouyang, Tian, Ye, Ke, Wang, Guiling, and Cao, Dianxue
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MANGANESE dioxide , *ELECTROCHEMISTRY , *CARBON nanotubes , *SUPERCAPACITOR electrodes , *NANOSTRUCTURED materials , *CHEMICAL stability - Abstract
Designing and fabricating self-supported and binder-free MnO 2 nanostructure electrode to overcome their low conductivity for supercapacitor application with high comprehensive electrochemical performance, such as high capacitance, excellent stability, and good rate capability, is still a tremendous challenge. In this paper, carbon nanotubes are uniform covered on nickel foam (denote as CNT/Ni) by a simple dip & dry method to form a 3D skeleton for MnO 2 nanosheets deposition (denoted as MnO 2 -CNT/Ni). Results show the MnO 2 -CNT/Ni electrode exhibits a unique 3D porous interconnected network with a high specific capacitance of 402.5 F g − 1 at 1 A g − 1 and a favorable cycling performance that 83% capacitance retained after 5000 cycles at a current density of 2 A g − 1 . Meanwhile, the MnO 2 -CNT/Ni//CNT/Ni asymmetric supercapacitor exhibits an excellent energy density of 25 Wh kg − 1 at a power density of 0.9 kW kg − 1 with 85.3% capacitance retention after 5000 cycles. Therefore, such a facile and manageable method to prepare MnO 2 electrode with high supercapacitor performance is offering a promising future for practical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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17. Facile dip coating processed 3D MnO2-graphene nanosheets/MWNT-Ni foam composites for electrochemical supercapacitors.
- Author
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Kong, Shuying, Cheng, Kui, Ouyang, Tian, Gao, Yinyi, Ye, Ke, Wang, Guiling, and Cao, Dianxue
- Subjects
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MANGANESE dioxide , *SURFACE coatings , *SUPERCAPACITORS , *NANOSTRUCTURED materials , *COMPOSITE materials , *GRAPHENE , *MULTIWALLED carbon nanotubes - Abstract
Carbon materials, especially graphene nanosheets (GNS) and/or multi-walled carbon nanotube (MWNT), have been widely used as electrode materials for supercapacitor due to their advantages of higher specific surface area and electronic conductivity, but the relatively low specific capacitance thus results in low energy density hindering their large applications. On the contrary, MnO 2 exhibits higher energy density but poor electrical conductivity. In order to obtain high performance supercapacitor electrode, here, combining the advantages of these materials, we have designed a facile two-step strategy to prepare 3D MnO 2 -GNS-MWNT-Ni foam (MnO 2 -GM-Ni) electrode. First, GNS and MWNT is wrapped on the surface of Ni foam (GM-Ni) via a “dip & dry” method by using an organic dye as a co-dispersant. Then, by using this 3D GM-Ni as substrate, MnO 2 nanoflakes are in-situ supporting on the surface of GNS and MWNT through a hydrothermal reaction. The specific capacitances of MnO 2 -GM-Ni electrode reach as high as 470.5 F g −1 at 1 A g −1 . Furthermore, we have successfully fabricated an asymmetric supercapacitor with MnO 2 -GM-Ni and GM-Ni as the positive and negative electrodes, respectively. The MnO 2 -GM-Ni//GM-Ni asymmetric supercapacitor exhibits a maximum energy density of 35.3 Wh kg −1 at a power density of 426 W kg −1 and also a favorable cycling performance that 83.8% capacitance retention after 5000 cycles. These results show manageable and high-performance which offer promising future for practical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
18. In-situ growth of cobalt oxide nanoflakes from cobalt nanosheet on nickel foam for battery-type supercapacitors with high specific capacity.
- Author
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Kong, Shuying, Yang, Fan, Cheng, Kui, Ouyang, Tian, Ye, Ke, Wang, Guiling, and Cao, Dianxue
- Subjects
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COBALT oxides , *COBALT alloys , *SUPERCAPACITOR performance , *NICKEL , *POROSITY - Abstract
Ni foam supported Co 3 O 4 nanoflakes is prepared for battery-type supercapacitor application through a simple three-step route. In briefly, Co metals are first deposited on Ni foam with a nanosheet morphology. The CoC 2 O 4 protrudes out from the surface of Co through an in-situ reaction with H 2 C 2 O 4 to form dendritic-like nanowires morphology. Finally, Co 3 O 4 are obtained through thermal decomposition of the CoC 2 O 4 precursor and the dendritic-like nanowires morphology is melting and transforming into a nanoflakes morphology. The unique architectures morphology with porosity and interconnected channels has great advantages since it can effectively increases the contact surface area with electrolyte, which could significantly not only enhances surface area but also the ion/electron diffusion. Electrochemical tests show that Co 3 O 4 nanoflakes exhibit a high specific capacity up to 576.8 C g − 1 at a current density of 1 A g − 1 and remain 283.7 C g − 1 capacity at a high current density of 50 A g − 1 , as well as 82% capacitance retained after 5000 cycles. These above results demonstrate the great potential of Co 3 O 4 nanoflakes in the development of battery-type supercapacitors. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. Preparation of binder-free porous ultrathin Ni(OH)2 nanoleafs using ZnO as pore forming agent displaying both high mass loading and excellent electrochemical energy storage performance.
- Author
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Xu, Panpan, Miao, Chenxu, Cheng, Kui, Ye, Ke, Yin, Jinling, Cao, Dianxue, Wang, Guiling, and Zhang, Xianfa
- Subjects
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ZINC oxide , *NICKEL alloys , *BINDING agents , *POROUS materials , *ELECTROCHEMICAL electrodes , *ENERGY storage , *CHEMICAL sample preparation - Abstract
Ni(OH) 2 has been reported widely as one of the most promising supercapactior electrode materials due to its high specific capacitance, yet which were only based on low mass loading. Thus, it is desirable to promote supercapacitor performance for high mass loading Ni(OH) 2 through optimizing microstructure. In this work, we first prepared crossed ultrathin Ni(OH) 2 /ZnO nanoleafs directly grown on nickel foam via hydrothermal method, and then we produced pores on the nanoleafs by dissolving ZnO in alkaline solution. Definitely, this unique structure design for high mass loading binder-free Ni(OH) 2 electrode could benefit the penetration of electrolyte and the transportation of electrons, efficiently improving the supercapacitor performance. The obtained porous Ni(OH) 2 /NF electrode exhibits a mass specific capacity of 1142C g −1 based on 10 mg active materials, equating to a areal specific capaciy of 11.4C cm −2 , and pleasant cycling stability with retention of 85% of initial capacity after 10000 charge-discharge cycles. The fabricated asymmetric device shows a high energy density of 42 Wh kg −1 (4.73 mWh cm −3 ) at power density of 105 W kg −1 (17 mW cm −3 ). These results demonstrate the optimized structure makes the high mass loading binder-free Ni(OH) 2 /NF electrode could also display excellent supercapacitor performance. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. High electrochemical energy storage performance of controllable synthesis of nanorod Cu1.92S accompanying nanoribbon CuS directly grown on copper foam.
- Author
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Xu, Panpan, Miao, Chenxu, Cheng, Kui, Ye, Ke, Yin, Jinling, Cao, Dianxue, Pan, Zhongcheng, Wang, Guiling, and Zhang, Xianfa
- Subjects
- *
ENERGY storage , *NANOROD synthesis , *NANORIBBONS , *COPPER sulfide , *ELECTRON transport , *SUPERCAPACITORS , *ELECTRIC capacity - Abstract
Facile in-situ etching current collector prepares corresponding oxide or sulfide, which is directly used as faradic electrode material, supplying faster electron transportation and better connection, and thus displaying good supercapacitor performance. Here, we prepare Cu x S via etching copper foam and investigate the influence of etching time on the morphology and electrochemical performance. The results show that compared with the nano-rod Cu x S-1h/CF, nano-rod/wire Cu x S-2h/CF and block/nanorod Cu x S-4h/CF, the nano-rod/ribbon Cu x S-3h/CF electrode exhibits the highest specific capacity (448.8C g −1 at current density of 5 mA cm −2 ). We fabricate asymmetric supercapacitor based on Cu x S-3h/CF as positive electrode and AC as negative electrode to further evaluate the supercapacitor property and the device achieves a high energy density of 35 Wh kg −1 at power density of 266 W kg −1 . Furthermore, the outstanding cycling stability of 88% capacitance retention after 5000 charge-discharge cycles more enable the Cu x S-3h/CF become promising faradic electrode material. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. A novel three-dimensional manganese dioxide electrode for high performance supercapacitors.
- Author
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Kong, Shuying, Cheng, Kui, Gao, Yinyi, Ouyang, Tian, Ye, Ke, Wang, Guiling, and Cao, Dianxue
- Subjects
- *
SUPERCAPACITOR performance , *MANGANESE dioxide electrodes , *CRYSTAL structure , *NANOWIRES , *TITANIUM carbide , *GRAPHENE - Abstract
Development of MnO 2 based electrode materials for supercapacitor application with high comprehensive electrochemical performance, such as high capacitance, superior reversibility, excellent stability, and good rate capability, is still a tremendous challenge. In this work, a distinctive interwoven three-dimensional (3D) structure electrode with ultra-thin 2D graphene nanosheet decorated on the surface of 1D C/TiC nanowire array is built as the support to immobilize MnO 2 nanoflakes (MnO 2 -Graphene nanosheet-C/TiC nanowire array, denoted as MGCT). Compared with the normal 1D core/shell structure, this novel 3D architecture can dramatically not only increase the surface area for MnO 2 loading but also facilitate the ion and electron transfer. The electrochemical performance of the as-prepared 3D MnO 2 electrode is evaluated by cyclic voltammetrys, galvanostatic charging-discharging tests and electrochemical impedance spectroscopy, high specific capacitance (856 F g −1 at 2 A g −1 ), good rate capability (69.1% capacitance retention at 40 A g −1 vs 2 A g −1 ), superior reversibility, and cycling stability (85.7% capacitance retention after 10,000 cycles at 10 A g −1 ) are obtained, suggesting that this novel structure can offer a new and appropriate idea for obtaining high-performance supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
22. PPy wrapped MnO2@C/TiO2 nanowire arrays for electrochemical energy storage.
- Author
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Yang, Sainan, Yan, Peng, Li, Yiju, Ye, Ke, Cheng, Kui, Cao, Dianxue, Wang, Guiling, and Li, Qiang
- Subjects
- *
MANGANESE oxides , *TITANIUM dioxide nanoparticles , *ELECTROCHEMICAL electrodes , *ENERGY storage , *WRAPPING materials , *SUPERCAPACITOR electrodes - Abstract
Herein, Polypyrrole was used as the conductive wrapping material electro-deposited on the MnO 2 nanoflakes covered on C/TiO 2 nanowire arrays to form PPy@MnO 2 @C/TiO 2 double shell/core structured arrays electrode for supercapacitor. Their structure and surface morphology were studied by using X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. The results suggest that a thin layer of PPy was successfully wrapped on the surface of MnO 2 , and the shell/core structure of MnO 2 @C/TiO 2 nanowire arrays was not changed after electro-deposition of PPy. The electrochemical tests indicate that the PPy@MnO 2 @C/TiO 2 double shell/core arrays electrode exhibits high specific capacitance of 715 F g −1 at a charge/discharge current density of 1 A g −1 and improved specific capacitance retention to 84.0% after 1000 cycles. These results show that the unique three dimensional (3D) double shell/core structured electrode holds promise for high-performance energy storage devices. The superior capacitive perfomance may due to the unique 3D C/TiO 2 nanowires and the unique double shell/core structures. Firstly, the 3D C/TiO 2 nanowire arrays, as excellent platform for loading active materials, can facilitate the permeation of electrolyte. Moreover, the thin layer PPy tightly wrapped on the MnO 2 nanoflakes can improve the electrical conductivity of MnO 2 . Therefore, the PPy@MnO 2 @C/TiO 2 electrode is promising candidate for electrochemical energy applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
23. Freestanding one-dimensional manganese dioxide nanoflakes-titanium cabide/carbon core/double shell arrays as ultra-high performance supercapacitor electrode.
- Author
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Kong, Shuying, Cheng, Kui, Ouyang, Tian, Ye, Ke, Gao, Yinyi, Wang, Guiling, and Cao, Dianxue
- Subjects
- *
SUPERCAPACITOR electrodes , *MANGANESE dioxide , *TITANIUM carbide , *CARBON electrodes , *STRUCTURAL shells , *X-ray photoelectron spectroscopy - Abstract
In this paper, freestanding one-dimensional MnO 2 nanoflakes are successful prepared through a simple hydrothermal reaction by using the carbon shell of TiC/C core/shell arrays as the sacrificial template. Its structure and morphology are characterized by X-ray diffractometer, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectrometer and transmission electron microscopy. Results show that the thickness of the carbon shell decreased but also remained and the ultrathin MnO 2 nanoflakes with thickness less than 5 nm uniformly grow on the surfaces of the TiC/C nanowire to form a core/double shell structure after the hydrothermal reaction. The electrochemical performance of the as-prepared electrode is evaluated by cyclic voltammetrys, galvanostatic charging-discharging tests and electrochemical impedance spectroscopy, and high capacities, excellent rate capabilities and exemplary cycling performance is obtained. The as-prepared electrode shows a high specific capacitance of 598.8 F g −1 and 85.8% of its initial capacitance is retained after 10,000 cycles at a high discharge current density of 10 A g −1 , suggesting that this structure has a promising future as high-performance supercapacitor electrode. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
24. Electrodeposition of nickel sulfide on graphene-covered make-up cotton as a flexible electrode material for high-performance supercapacitors.
- Author
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Li, Yiju, Ye, Ke, Cheng, Kui, Yin, Jinling, Cao, Dianxue, and Wang, Guiling
- Subjects
- *
ELECTROFORMING , *NICKEL sulfide , *SUPERCAPACITOR performance , *GRAPHENE , *ELECTROLYTE analysis , *ELECTRODES - Abstract
In this report, graphene nanosheets (GNS)/nickel sulfide (NiS) based material for high-performance supercapacitor is prepared by “dip and dry” and electrodeposition methods. Commercial flexible make-up cottons (MCs) are chose as skeletons to construct homogeneous three-dimensional (3D) interconnected graphene-wrapped macro-networks, which can support structures for high loading of active electrode materials and facilitate the access of electrolytes to active electrode materials. The hybrid GNS/NiS based MCs (denoted as MCs@GNS@NiS) electrode yields relatively high specific capacitance of 775 F g −1 at a charge/discharge specific current of 0.5 A g −1 and good capacitance retention of 88.1% after 1000 cycles at 2 A g −1 . Furthermore, the MCs@GNS@NiS electrode delivers a high energy density of 11.2 Wh kg −1 at even a high power density of 1008 W kg −1 . Therefore, such low-cost and high-performance energy MCs based on GNS/NiS hierarchical nanostructures offer great promise in large-scale energy storage device applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
25. Facile preparation of three-dimensional multilayer porous MnO2/reduced graphene oxide composite and its supercapacitive performance.
- Author
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Li, Yiju, Wang, Guiling, Ye, Ke, Cheng, Kui, Pan, Yue, Yan, Peng, Yin, Jinling, and Cao, Dianxue
- Subjects
- *
POROUS materials , *CHEMICAL sample preparation , *MANGANESE oxides , *CHEMICAL reduction , *GRAPHENE oxide , *SUPERCAPACITORS - Abstract
Three-dimensional (3D) multilayer porous MnO 2 /reduced graphene oxide composites are coated on a nickel foam substrate (denoted as MnO 2 /R-GO@Ni-foam) by a facile and scalable spray method following by low temperature annealing. The composite electrodes are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The content of MnO 2 in the MnO 2 /R-GO@Ni-foam composites is determined by thermal gravimetric analysis. The supercapacitive performance of the composite electroides is investigated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The results show that the MnO 2 /R-GO@Ni-foam composite displays a high specific capacitance of 267 F g −1 at 0.25 A g −1 and excellent capacitance retention of 89.5% after 1000 cycles. This study provides a facile way for the preparation of composite electrodes for high-performance supercapacitor. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. Binder-free ultrathin α-MnSe nanosheets for high performance supercapacitor.
- Author
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Miao, Chenxu, Fang, Yongzheng, Zhu, Kai, Zhou, Chunliang, Ye, Ke, Yan, Jun, Cao, Dianxue, Wang, Guiling, Xu, Panpan, and Xie, Chunling
- Subjects
- *
NANOSTRUCTURED materials , *SUPERCAPACITOR performance , *SUPERCAPACITORS , *ENERGY density , *ENERGY storage , *ELECTRIC conductivity , *SUPERCAPACITOR electrodes - Abstract
• α-MnSe Nanosheets are prepared via a facile hydrothermal method. • The effect of reaction time on electrochemical performance is investigated. • The α-MnSe electrode delivers a high capacity of 88.3 mAh g−1 at 1 A g−1. • The asymmetric supercapacitor exhibits a high energy density of 39.3 Wh kg−1. Transition metal selenides are regarded as emerging materials for energy storage devices because of their good electrical conductivity and electrochemical activity. Here, a binder-free ultrathin α-MnSe nanosheets electrode is prepared and the supercapacitor performance is comprehensively explored. Due to the increased active sites, enlarged contact area for electrolyte, as well as shorten ions diffusion pathway, the prepared electrode delivers high capacity of 88.3 mAh g−1 at 1 A g−1, good rate capability, and long-term durability (91% remain after 5000 cycles). Moreover, the asymmetric supercapacitor, fabricated by α-MnSe anode and active carbon cathode, displays a high energy density of 39.3 Wh kg−1 at a power density of 0.92 kW kg−1 and satisfying cycle performance. This study demonstrates that the binder-free α-MnSe electrode holds great promise for supercapacitor. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. Hollow Co–Mo–Se nanosheet arrays derived from metal-organic framework for high-performance supercapacitors.
- Author
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Miao, Chenxu, Zhou, Chunliang, Wang, Hong-En, Zhu, Kai, Ye, Ke, Wang, Qian, Yan, Jun, Cao, Dianxue, Li, Neng, and Wang, Guiling
- Subjects
- *
METAL-organic frameworks , *ENERGY density , *ENERGY storage , *ION exchange (Chemistry) , *CHARGE transfer , *SUPERCAPACITORS , *SUPERCAPACITOR electrodes , *MOLYBDENUM - Abstract
Developing novel materials with rational structures and excellent electrical conductivity is vitally important for energy storage devices. Herein, hollow cobalt molybdenum selenide (Co–Mo–Se) nanosheet arrays are fabricated via a self-sacrificing template method and selenization process, where cobalt-organic framework serves as the template. Benefiting from unique hollow nanoarrays structure, the Co–Mo–Se electrode offers rich electroactive sites, large accessible regions for electrolyte, and short ions diffusion pathways. Additionally, it is observed that the Co–Mo–Se possesses a low charge transfer resistance owing to the intrinsic metallicity. As a result, the Co–Mo–Se electrode exhibits favorable energy storage properties, including high capacity (221.7 mAh g−1), good rate property, and outstanding stability (95% after 8000 cycles). More importantly, the assembled Co–Mo–Se//active carbon (AC) achieves high energy density (44.7 Wh kg−1) and remarkable durability. Notably, two hybrid devices connected in series successfully power an electronic watch for 70 min, demonstrating its practical applicability. These results indicate that the synthesized hollow Co–Mo–Se nanosheet arrays have promising applications as electrode materials for high-performance energy storage devices. • Co-MOF was employed as template to obtain hollow Co–Mo–Se nanosheet arrays. • The Co–Mo–Se delivers a specific capacity of 221.7 mAh g−1 at 1 A g−1. • The ion exchange/etching method was applied in this work. • The asymmetric supercapacitor delivers high energy and power densities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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