A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning ele...A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning electron microscope and electrochemical methods. The results show that the particles of tin oxide-based materials form an interconnected network structure like mesoporous material. The average size of the particles is about 200 nm. The materials deliver a charge capacity of more than 570 mA·h·g-1. And the capacity loss per cycle is about 0.15% after being cycled for 30 times. The good electrochemical performance indicates that tin oxide-based materials are promising anodes for lithium ion batteries.展开更多
Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electro...Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis （TG/DTA）, X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co3O4/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mA-h/g as the calcination temperature increases from 300 to 500 ℃, and the Co304/graphite composites synthesized at 400 ℃ show the best cycling stability without capacity loss in the initial 20 cycles. peaks, corresponding to the lithium intercalaction/deintercalation for The CV profile of the composite presents two couples of redox graphite and Co3O4, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.展开更多
A series of composites as electrode materials for supercapacitors were prepared via incipient wetness impregnation method utilizing ordered mesoporous carbon （OMC） and tin （IV） oxide （SnO2） with different ratio....A series of composites as electrode materials for supercapacitors were prepared via incipient wetness impregnation method utilizing ordered mesoporous carbon （OMC） and tin （IV） oxide （SnO2） with different ratio.The structure and electrochemical properties of the OMC/SnO2 composites were characterized by XRD,TEM and cyclic voltammetry （CV）.Pore characteristics were measured by nitrogen adsorption and desorption isotherms.The results show that the structure and electrochemical properties of the composites depend mainly on the loading amount of SnO2 in the ordered mesoporous carbon.The optimum amount of SnCl4 added is found to be 40 % （1.54 g ethanol-based SnCl4·5H2O added to 1 g OMC） of the saturated solution.The specific capacitance of the composite of optimum amount of SnCl4 （200 F g-1） is nearly three times of that of the pristine SnO2 （72 F g-1） at the scan rate of 5 mV s-1,and its specific capacitance is almost equal to that of the ordered mesoporous carbon （126 F g-1） at the scan rate of 200 mV s-1.Meanwhile,it has better specific volumetric energy density than OMC due to its higher density.Besides,in the potential range of 0-0.9 V the composite electrode material exhibits a stable cycle life after 500 cycles.展开更多
Taking the nano-sized carbon black and aniline monomer as precursor and （NH4）2S2O6 as oxidant, the well coated C/polyaniline（C/PANI） composite materials were prepared by in situ polymerization of the aniline on th...Taking the nano-sized carbon black and aniline monomer as precursor and （NH4）2S2O6 as oxidant, the well coated C/polyaniline（C/PANI） composite materials were prepared by in situ polymerization of the aniline on the surface of well-dispersed nano-sized carbon black for supercapacitor. The micro-structure of the C/PANI composite electrode materials were analyzed by SEM. The electrochemical properties of C/ PANI and PANI composite electrode were characterized by means of the galvanostatic charge-discharge experiment, cyclic voltammetric measurement and impedance spectroscopy analysis. The results show that by adding the nano-sized carbon black in the process of chemical polymerization of the aniline, the polyaniline can be in situ polymerized and well-coated onto the carbon black particles, which may effectively improve the aggregation of particles and the electrolyte penetration. What’s more , the maximum of specific capacitance of C/PANI electrode 437.6F·g -1 can be attained. Compared with PANI electrode, C/PANI electrode shows more desired capacitance characteristics, smaller internal resistance and better cycle performance.展开更多
Synthesis of nanostructured Ru-doped SnO2 was successfully carried out using the reverse microemulsion method. The phase purity and the crystallite size were analyzed by XRD. The surface morphology and the microstruct...Synthesis of nanostructured Ru-doped SnO2 was successfully carried out using the reverse microemulsion method. The phase purity and the crystallite size were analyzed by XRD. The surface morphology and the microstructure of synthesized nanoparticles were analyzed by SEM and TEM. The vibration mode of nanoparticles was investigated using FTIR and Raman studies. The electrochemical behavior of the Ru- doped SnO2 electrode was evaluated in a 0.1 mol/L Na2SO4 solution using cyclic voltammetry. The 5% Ru-doped SnO2 electrode exhibited a high specific capacitance of 535.6 Fig at a scan rate 20 mV/s, possessing good conductivity as well as the electro- cycling stability. The Ru-doped SnO2 composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.展开更多
文摘A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning electron microscope and electrochemical methods. The results show that the particles of tin oxide-based materials form an interconnected network structure like mesoporous material. The average size of the particles is about 200 nm. The materials deliver a charge capacity of more than 570 mA·h·g-1. And the capacity loss per cycle is about 0.15% after being cycled for 30 times. The good electrochemical performance indicates that tin oxide-based materials are promising anodes for lithium ion batteries.
基金Project(2007CB613607) supported by the National Basic Research Program of China Projects(2009FJ1002, 2009CK3062) supported by the Science and Technology Program of Hunan Province, China
文摘Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis （TG/DTA）, X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co3O4/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mA-h/g as the calcination temperature increases from 300 to 500 ℃, and the Co304/graphite composites synthesized at 400 ℃ show the best cycling stability without capacity loss in the initial 20 cycles. peaks, corresponding to the lithium intercalaction/deintercalation for The CV profile of the composite presents two couples of redox graphite and Co3O4, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.
基金Funded by Science and Technology Commission of Shanghai Municipality (No.0952nm02500)
文摘A series of composites as electrode materials for supercapacitors were prepared via incipient wetness impregnation method utilizing ordered mesoporous carbon （OMC） and tin （IV） oxide （SnO2） with different ratio.The structure and electrochemical properties of the OMC/SnO2 composites were characterized by XRD,TEM and cyclic voltammetry （CV）.Pore characteristics were measured by nitrogen adsorption and desorption isotherms.The results show that the structure and electrochemical properties of the composites depend mainly on the loading amount of SnO2 in the ordered mesoporous carbon.The optimum amount of SnCl4 added is found to be 40 % （1.54 g ethanol-based SnCl4·5H2O added to 1 g OMC） of the saturated solution.The specific capacitance of the composite of optimum amount of SnCl4 （200 F g-1） is nearly three times of that of the pristine SnO2 （72 F g-1） at the scan rate of 5 mV s-1,and its specific capacitance is almost equal to that of the ordered mesoporous carbon （126 F g-1） at the scan rate of 200 mV s-1.Meanwhile,it has better specific volumetric energy density than OMC due to its higher density.Besides,in the potential range of 0-0.9 V the composite electrode material exhibits a stable cycle life after 500 cycles.
基金Project(2005CB623703) supported by the National Basic Research Program of China project(5JJ30103) supported bythe Natural Science Foundation of Hunan Province
文摘Taking the nano-sized carbon black and aniline monomer as precursor and （NH4）2S2O6 as oxidant, the well coated C/polyaniline（C/PANI） composite materials were prepared by in situ polymerization of the aniline on the surface of well-dispersed nano-sized carbon black for supercapacitor. The micro-structure of the C/PANI composite electrode materials were analyzed by SEM. The electrochemical properties of C/ PANI and PANI composite electrode were characterized by means of the galvanostatic charge-discharge experiment, cyclic voltammetric measurement and impedance spectroscopy analysis. The results show that by adding the nano-sized carbon black in the process of chemical polymerization of the aniline, the polyaniline can be in situ polymerized and well-coated onto the carbon black particles, which may effectively improve the aggregation of particles and the electrolyte penetration. What’s more , the maximum of specific capacitance of C/PANI electrode 437.6F·g -1 can be attained. Compared with PANI electrode, C/PANI electrode shows more desired capacitance characteristics, smaller internal resistance and better cycle performance.
文摘Synthesis of nanostructured Ru-doped SnO2 was successfully carried out using the reverse microemulsion method. The phase purity and the crystallite size were analyzed by XRD. The surface morphology and the microstructure of synthesized nanoparticles were analyzed by SEM and TEM. The vibration mode of nanoparticles was investigated using FTIR and Raman studies. The electrochemical behavior of the Ru- doped SnO2 electrode was evaluated in a 0.1 mol/L Na2SO4 solution using cyclic voltammetry. The 5% Ru-doped SnO2 electrode exhibited a high specific capacitance of 535.6 Fig at a scan rate 20 mV/s, possessing good conductivity as well as the electro- cycling stability. The Ru-doped SnO2 composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.
基金supported by the National Natural Science Foundation of China(51072137,50802064,11074189)Key Projects in the National Science&Technology Pillar Program,China(2009BAC62B02)Shanghai Committee of Science and Technology,China(11nm0501600)~~
