The Experts below are selected from a list of 8562 Experts worldwide ranked by ideXlab platform
Lingjuan Deng - One of the best experts on this subject based on the ideXlab platform.
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ruo2 graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Jianfang Wang, Liping Kang, Zupei YangAbstract:Abstract Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g−1 has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F g−1 obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2·xH2O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L−1 H2SO4 solution as the electrolyte in a voltage of 0–1.2 V. It can give a high energy density of 20.28 Wh kg−1 at a power density of 600 W kg−1. Moreover, it presents a high power density (14.03 Wh kg−1 at 12 kW kg−1) and excellent cycle performance.
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RuO2/graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zhibin Lei, Gang Zhu, Jiasi Wang, Liping Kang, Zong Huai LiuAbstract:Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g(-1) has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F ri obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2 center dot xH(2)O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L-1 H2SO4 solution as the electrolyte in a voltage of 0-1.2 V. It can give a high energy density of 20.28 Wh kg(-1) at a power density of 600 W kg(-1). Moreover, it presents a high power density (14.03 Wh kg(-1) at 12 kW kg(-1)) and excellent cycle performance. (C) 2013 Elsevier B.V. All rights reserved.
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graphene vo2 hybrid material for high performance Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Gaini Zhang, Liping KangAbstract:Vanadium oxides have attracted significant attention for Electrochemical Capacitor because of their extensive multifunctional properties. In the present work, graphene/VO2 (RG/VO2) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO2 particles with starfruit morphology. The starfruit-like VO2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g−1 has been achieved for RG(1.0)/VO2 electrode with RG content of 26 wt% in 0.5 mol L−1 K2SO4 electrolyte. An asymmetrical Electrochemical Capacitor is assembled by using RG(1.0)/VO2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L−1 K2SO4 electrolyte. The asymmetrical Capacitor can deliver an energy density of 22.8 Wh kg−1 at a power density of 425 W kg−1, much higher than those of the symmetrical Electrochemical Capacitor based on the RG and RG(1.0)/VO2 electrodes. Moreover, the asymmetrical Capacitor preserves 81% of its initial capacitance over 1000 cycles at a current density of 5 A g−1.
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Graphene/VO2 hybrid material for high performance Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Gaini Zhang, Liping KangAbstract:Vanadium oxides have attracted significant attention for Electrochemical Capacitor because of their extensive multifunctional properties. In the present work, graphene/VO2 (RG/VO2) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO2 particles with starfruit morphology. The starfruit-like VO2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g−1 has been achieved for RG(1.0)/VO2 electrode with RG content of 26 wt% in 0.5 mol L−1 K2SO4 electrolyte. An asymmetrical Electrochemical Capacitor is assembled by using RG(1.0)/VO2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L−1 K2SO4 electrolyte. The asymmetrical Capacitor can deliver an energy density of 22.8 Wh kg−1 at a power density of 425 W kg−1, much higher than those of the symmetrical Electrochemical Capacitor based on the RG and RG(1.0)/VO2 electrodes. Moreover, the asymmetrical Capacitor preserves 81% of its initial capacitance over 1000 cycles at a current density of 5 A g−1.
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preparation and capacitance of graphene multiwall carbon nanotubes mno2 hybrid material for high performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract Graphene/multiwall carbon nanotubes/MnO 2 (GR/MCNTs/MnO 2 ) hybrid material with a specific capacitance of 126 F g −1 within a potential window of 0–1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO 4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO 2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO 2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L −1 Na 2 SO 4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0–2.0 V and gives a high energy density of 28.33 Wh kg −1 , which is much higher than those of symmetrical ECs based on GR/MCNT/MnO 2 (6.20 Wh kg −1 ) and GR/MCNT (3.92 Wh kg −1 ). Moreover, the asymmetrical EC presents a high power density (5 kW kg −1 at 13.33 Wh kg −1 ) and excellent cycling performance of 83% retention after 2500 cycles.
Liping Kang - One of the best experts on this subject based on the ideXlab platform.
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ruo2 graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Jianfang Wang, Liping Kang, Zupei YangAbstract:Abstract Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g−1 has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F g−1 obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2·xH2O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L−1 H2SO4 solution as the electrolyte in a voltage of 0–1.2 V. It can give a high energy density of 20.28 Wh kg−1 at a power density of 600 W kg−1. Moreover, it presents a high power density (14.03 Wh kg−1 at 12 kW kg−1) and excellent cycle performance.
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RuO2/graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zhibin Lei, Gang Zhu, Jiasi Wang, Liping Kang, Zong Huai LiuAbstract:Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g(-1) has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F ri obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2 center dot xH(2)O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L-1 H2SO4 solution as the electrolyte in a voltage of 0-1.2 V. It can give a high energy density of 20.28 Wh kg(-1) at a power density of 600 W kg(-1). Moreover, it presents a high power density (14.03 Wh kg(-1) at 12 kW kg(-1)) and excellent cycle performance. (C) 2013 Elsevier B.V. All rights reserved.
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graphene vo2 hybrid material for high performance Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Gaini Zhang, Liping KangAbstract:Vanadium oxides have attracted significant attention for Electrochemical Capacitor because of their extensive multifunctional properties. In the present work, graphene/VO2 (RG/VO2) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO2 particles with starfruit morphology. The starfruit-like VO2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g−1 has been achieved for RG(1.0)/VO2 electrode with RG content of 26 wt% in 0.5 mol L−1 K2SO4 electrolyte. An asymmetrical Electrochemical Capacitor is assembled by using RG(1.0)/VO2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L−1 K2SO4 electrolyte. The asymmetrical Capacitor can deliver an energy density of 22.8 Wh kg−1 at a power density of 425 W kg−1, much higher than those of the symmetrical Electrochemical Capacitor based on the RG and RG(1.0)/VO2 electrodes. Moreover, the asymmetrical Capacitor preserves 81% of its initial capacitance over 1000 cycles at a current density of 5 A g−1.
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Graphene/VO2 hybrid material for high performance Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Gaini Zhang, Liping KangAbstract:Vanadium oxides have attracted significant attention for Electrochemical Capacitor because of their extensive multifunctional properties. In the present work, graphene/VO2 (RG/VO2) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO2 particles with starfruit morphology. The starfruit-like VO2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g−1 has been achieved for RG(1.0)/VO2 electrode with RG content of 26 wt% in 0.5 mol L−1 K2SO4 electrolyte. An asymmetrical Electrochemical Capacitor is assembled by using RG(1.0)/VO2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L−1 K2SO4 electrolyte. The asymmetrical Capacitor can deliver an energy density of 22.8 Wh kg−1 at a power density of 425 W kg−1, much higher than those of the symmetrical Electrochemical Capacitor based on the RG and RG(1.0)/VO2 electrodes. Moreover, the asymmetrical Capacitor preserves 81% of its initial capacitance over 1000 cycles at a current density of 5 A g−1.
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preparation and capacitance of graphene multiwall carbon nanotubes mno2 hybrid material for high performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract Graphene/multiwall carbon nanotubes/MnO 2 (GR/MCNTs/MnO 2 ) hybrid material with a specific capacitance of 126 F g −1 within a potential window of 0–1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO 4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO 2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO 2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L −1 Na 2 SO 4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0–2.0 V and gives a high energy density of 28.33 Wh kg −1 , which is much higher than those of symmetrical ECs based on GR/MCNT/MnO 2 (6.20 Wh kg −1 ) and GR/MCNT (3.92 Wh kg −1 ). Moreover, the asymmetrical EC presents a high power density (5 kW kg −1 at 13.33 Wh kg −1 ) and excellent cycling performance of 83% retention after 2500 cycles.
Zupei Yang - One of the best experts on this subject based on the ideXlab platform.
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ruo2 graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Jianfang Wang, Liping Kang, Zupei YangAbstract:Abstract Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g−1 has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F g−1 obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2·xH2O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L−1 H2SO4 solution as the electrolyte in a voltage of 0–1.2 V. It can give a high energy density of 20.28 Wh kg−1 at a power density of 600 W kg−1. Moreover, it presents a high power density (14.03 Wh kg−1 at 12 kW kg−1) and excellent cycle performance.
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RuO2/graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zhibin Lei, Gang Zhu, Jiasi Wang, Liping Kang, Zong Huai LiuAbstract:Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g(-1) has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F ri obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2 center dot xH(2)O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L-1 H2SO4 solution as the electrolyte in a voltage of 0-1.2 V. It can give a high energy density of 20.28 Wh kg(-1) at a power density of 600 W kg(-1). Moreover, it presents a high power density (14.03 Wh kg(-1) at 12 kW kg(-1)) and excellent cycle performance. (C) 2013 Elsevier B.V. All rights reserved.
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preparation and capacitance of graphene multiwall carbon nanotubes mno2 hybrid material for high performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract Graphene/multiwall carbon nanotubes/MnO 2 (GR/MCNTs/MnO 2 ) hybrid material with a specific capacitance of 126 F g −1 within a potential window of 0–1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO 4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO 2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO 2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L −1 Na 2 SO 4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0–2.0 V and gives a high energy density of 28.33 Wh kg −1 , which is much higher than those of symmetrical ECs based on GR/MCNT/MnO 2 (6.20 Wh kg −1 ) and GR/MCNT (3.92 Wh kg −1 ). Moreover, the asymmetrical EC presents a high power density (5 kW kg −1 at 13.33 Wh kg −1 ) and excellent cycling performance of 83% retention after 2500 cycles.
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Preparation and capacitance of graphene/multiwall carbon nanotubes/MnO 2 hybrid material for high-performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zong Huai Liu, Jianfang Wang, Gang Zhu, Liping Kang, Zenglin WangAbstract:Graphene/multiwall carbon nanotubes/MnO2 (GR/MCNTs/MnO 2) hybrid material with a specific capacitance of 126 F g -1 within a potential window of 0-1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge-discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L-1 Na2SO4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0-2.0 V and gives a high energy density of 28.33 Wh kg-1, which is much higher than those of symmetrical ECs based on GR/MCNT/MnO2 (6.20 Wh kg-1) and GR/MCNT (3.92 Wh kg-1). Moreover, the asymmetrical EC presents a high power density (5 kW kg-1 at 13.33 Wh kg-1) and excellent cycling performance of 83% retention after 2500 cycles. ?? 2012 Elsevier Ltd. All Rights Reserved.
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graphene mno2 and graphene asymmetrical Electrochemical Capacitor with a high energy density in aqueous electrolyte
Journal of Power Sources, 2011Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract The graphene–manganese oxide hybrid material has been prepared by solution-phase assembly of aqueous dispersions of graphene nanosheets and manganese oxide nanosheets at room temperature. The morphology and structure of the obtained material are examined by scanning electron microscopy, transition electron microscopy, X-ray diffraction and N 2 adsorption–desorption. Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. An asymmetric Electrochemical Capacitor with high energy and power densities based on the graphene–manganese oxide hybrid material as positive electrode and graphene as negative electrode in a neutral aqueous Na 2 SO 4 solution as electrolyte is assembled. The asymmetrical Electrochemical Capacitor could cycle reversibly in a voltage of 0–1.7 V and give an energy density of 10.03 Wh kg −1 even at an average power density of 2.53 kW kg −1 . Moreover, the asymmetrical Electrochemical Capacitor exhibit excellent cycle stability, and the capacitance retention of the asymmetrical Electrochemical Capacitor is 69% after repeating the galvanostatic charge–discharge test at the constant current density of 2230 mA g −1 for 10,000 cycles.
Zenglin Wang - One of the best experts on this subject based on the ideXlab platform.
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preparation and capacitance of graphene multiwall carbon nanotubes mno2 hybrid material for high performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract Graphene/multiwall carbon nanotubes/MnO 2 (GR/MCNTs/MnO 2 ) hybrid material with a specific capacitance of 126 F g −1 within a potential window of 0–1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO 4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO 2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO 2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L −1 Na 2 SO 4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0–2.0 V and gives a high energy density of 28.33 Wh kg −1 , which is much higher than those of symmetrical ECs based on GR/MCNT/MnO 2 (6.20 Wh kg −1 ) and GR/MCNT (3.92 Wh kg −1 ). Moreover, the asymmetrical EC presents a high power density (5 kW kg −1 at 13.33 Wh kg −1 ) and excellent cycling performance of 83% retention after 2500 cycles.
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Preparation and capacitance of graphene/multiwall carbon nanotubes/MnO 2 hybrid material for high-performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zong Huai Liu, Jianfang Wang, Gang Zhu, Liping Kang, Zenglin WangAbstract:Graphene/multiwall carbon nanotubes/MnO2 (GR/MCNTs/MnO 2) hybrid material with a specific capacitance of 126 F g -1 within a potential window of 0-1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge-discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L-1 Na2SO4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0-2.0 V and gives a high energy density of 28.33 Wh kg-1, which is much higher than those of symmetrical ECs based on GR/MCNT/MnO2 (6.20 Wh kg-1) and GR/MCNT (3.92 Wh kg-1). Moreover, the asymmetrical EC presents a high power density (5 kW kg-1 at 13.33 Wh kg-1) and excellent cycling performance of 83% retention after 2500 cycles. ?? 2012 Elsevier Ltd. All Rights Reserved.
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graphene mno2 and graphene asymmetrical Electrochemical Capacitor with a high energy density in aqueous electrolyte
Journal of Power Sources, 2011Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract The graphene–manganese oxide hybrid material has been prepared by solution-phase assembly of aqueous dispersions of graphene nanosheets and manganese oxide nanosheets at room temperature. The morphology and structure of the obtained material are examined by scanning electron microscopy, transition electron microscopy, X-ray diffraction and N 2 adsorption–desorption. Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. An asymmetric Electrochemical Capacitor with high energy and power densities based on the graphene–manganese oxide hybrid material as positive electrode and graphene as negative electrode in a neutral aqueous Na 2 SO 4 solution as electrolyte is assembled. The asymmetrical Electrochemical Capacitor could cycle reversibly in a voltage of 0–1.7 V and give an energy density of 10.03 Wh kg −1 even at an average power density of 2.53 kW kg −1 . Moreover, the asymmetrical Electrochemical Capacitor exhibit excellent cycle stability, and the capacitance retention of the asymmetrical Electrochemical Capacitor is 69% after repeating the galvanostatic charge–discharge test at the constant current density of 2230 mA g −1 for 10,000 cycles.
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Graphene–MnO2 and graphene asymmetrical Electrochemical Capacitor with a high energy density in aqueous electrolyte
Journal of Power Sources, 2011Co-Authors: Lingjuan Deng, Zupei Yang, Jianfang Wang, Liping Kang, Zenglin WangAbstract:Abstract The graphene–manganese oxide hybrid material has been prepared by solution-phase assembly of aqueous dispersions of graphene nanosheets and manganese oxide nanosheets at room temperature. The morphology and structure of the obtained material are examined by scanning electron microscopy, transition electron microscopy, X-ray diffraction and N 2 adsorption–desorption. Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge–discharge and Electrochemical impedance spectroscopy. An asymmetric Electrochemical Capacitor with high energy and power densities based on the graphene–manganese oxide hybrid material as positive electrode and graphene as negative electrode in a neutral aqueous Na 2 SO 4 solution as electrolyte is assembled. The asymmetrical Electrochemical Capacitor could cycle reversibly in a voltage of 0–1.7 V and give an energy density of 10.03 Wh kg −1 even at an average power density of 2.53 kW kg −1 . Moreover, the asymmetrical Electrochemical Capacitor exhibit excellent cycle stability, and the capacitance retention of the asymmetrical Electrochemical Capacitor is 69% after repeating the galvanostatic charge–discharge test at the constant current density of 2230 mA g −1 for 10,000 cycles.
Zong Huai Liu - One of the best experts on this subject based on the ideXlab platform.
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RuO2/graphene hybrid material for high performance Electrochemical Capacitor
Journal of Power Sources, 2014Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zhibin Lei, Gang Zhu, Jiasi Wang, Liping Kang, Zong Huai LiuAbstract:Ruthenium oxide/graphene (RuO2/GR) hybrid materials for high performance Electrochemical Capacitor have been prepared by a solution-phase assembly technology between RuO2 nanosheets and GR nanosheets at room temperature. The high dispersion of RuO2 and GR nanosheets maintains a high structural stability for the hybrid material, and causes an obvious synergistic effect between the RuO2 and GR nanosheets. A specific capacitance of 479 F g(-1) has been obtained for the hybrid material with RuO2 mass content of 40% (abbreviated as RuGR46), and a high specific capacitance of 998 F ri obtained for RuO2 in the electrode. The utilization of RuO2 in the RuGR46 hybrid material increases by adding GR, and the capacitance of RuGR46 is quite comparable to that of the pristine RuO2 center dot xH(2)O while 60 wt% of RuO2 can be saved. A symmetrical Electrochemical Capacitor based on the RuGR46 electrode is assembled with 0.5 mol L-1 H2SO4 solution as the electrolyte in a voltage of 0-1.2 V. It can give a high energy density of 20.28 Wh kg(-1) at a power density of 600 W kg(-1). Moreover, it presents a high power density (14.03 Wh kg(-1) at 12 kW kg(-1)) and excellent cycle performance. (C) 2013 Elsevier B.V. All rights reserved.
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Graphene/VO2 hybrid material for high performance Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, G.a b Zhang, C.a b Liu, Zhibin Lei, Liping Kang, Zong Huai LiuAbstract:Vanadium oxides have attracted significant attention for Electrochemical Capacitor because of their extensive multifunctional properties. In the present work, graphene/VO2 (RG/VO2) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO2 particles with starfruit morphology. The starfruit-like VO2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode-electrolyte contact better. A high specific capacitance of 225 F g-1 has been achieved for RG(1.0)/VO2 electrode with RG content of 26 wt% in 0.5 mol L -1 K2SO4 electrolyte. An asymmetrical Electrochemical Capacitor is assembled by using RG(1.0)/VO2 as positive electrode and RG as negative electrode, and it can be reversibly charged-discharged at a cell voltage of 1.7 V in 0.5 mol L-1 K 2SO4 electrolyte. The asymmetrical Capacitor can deliver an energy density of 22.8 Wh kg-1 at a power density of 425 W kg -1, much higher than those of the symmetrical Electrochemical Capacitor based on the RG and RG(1.0)/VO2 electrodes. Moreover, the asymmetrical Capacitor preserves 81% of its initial capacitance over 1000 cycles at a current density of 5 A g-1. © 2013 Published by Elsevier Ltd.
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Preparation and capacitance of graphene/multiwall carbon nanotubes/MnO 2 hybrid material for high-performance asymmetrical Electrochemical Capacitor
Electrochimica Acta, 2013Co-Authors: Lingjuan Deng, Zupei Yang, Zhengping Hao, Zong Huai Liu, Jianfang Wang, Gang Zhu, Liping Kang, Zenglin WangAbstract:Graphene/multiwall carbon nanotubes/MnO2 (GR/MCNTs/MnO 2) hybrid material with a specific capacitance of 126 F g -1 within a potential window of 0-1.1 V vs. saturated calomel electrode has been synthesized by a simple redox reaction between graphene/multiwall carbon nanotubes (GR/MCNTs) and KMnO4 at room temperature. The morphology and structure of the obtained material are examined by XRD, SEM and TEM. The Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge-discharge and Electrochemical impedance spectroscopy. The mass percentage of MnO2 with layered structure is 37% in the hybrid material. An asymmetrical Electrochemical Capacitor (EC) is assembled using GR/MCNT/MnO2 hybrid material as positive electrode and GR/MCNT material as negative electrode, respectively. The Electrochemical properties of the two electrodes and the asymmetrical EC are investigated in 1 mol L-1 Na2SO4 aqueous electrolyte. The asymmetrical EC can cycle reversibly in a cell potential of 0-2.0 V and gives a high energy density of 28.33 Wh kg-1, which is much higher than those of symmetrical ECs based on GR/MCNT/MnO2 (6.20 Wh kg-1) and GR/MCNT (3.92 Wh kg-1). Moreover, the asymmetrical EC presents a high power density (5 kW kg-1 at 13.33 Wh kg-1) and excellent cycling performance of 83% retention after 2500 cycles. ?? 2012 Elsevier Ltd. All Rights Reserved.