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Kexin Tang - One of the best experts on this subject based on the ideXlab platform.
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self reduced vo vox Carbon Nanofiber composite as binder free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Yi Zhang, Kexin Tang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Self-reduced VO/VOx/Carbon Nanofiber composite as binder-free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Kexin Tang, Yi Zhang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
Jun Yang - One of the best experts on this subject based on the ideXlab platform.
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self reduced vo vox Carbon Nanofiber composite as binder free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Yi Zhang, Kexin Tang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Self-reduced VO/VOx/Carbon Nanofiber composite as binder-free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Kexin Tang, Yi Zhang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
Yi Zhang - One of the best experts on this subject based on the ideXlab platform.
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self reduced vo vox Carbon Nanofiber composite as binder free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Yi Zhang, Kexin Tang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Self-reduced VO/VOx/Carbon Nanofiber composite as binder-free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Kexin Tang, Yi Zhang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Effective Young's modulus of Carbon Nanofiber array
Journal of Materials Research, 2006Co-Authors: Yi Zhang, Ephraim SuhirAbstract:We developed a methodology for the evaluation of the effective Young's modulus (EYM) of the vertically aligned Carbon Nanofibers array (CNFA). The Carbon Nanofibers array is treated in this study as a continuous structural element, and, for this reason, the determined EYM might be appreciably different (actually, lower) than the Young's modulus (YM) of the material of an individual Carbon nanotube or a Nanofiber. The developed methodology is based on the application of a compressive load onto the Carbon Nanofibers array, so that each individual Carbon Nanofiber experiences axial compression and is expected to buckle under the compressive load. The relationship between the applied compressive stress and the induced displacement of the Carbon Nanofiber array is measured using a table version of an Instron tester. It has been found that the Carbon Nanofiber array exhibits nonlinear behavior and the EYM increases with an increase in the compressive load. The largest measured EYM of the Carbon Nanofiber array turned out to be about 90 GPa. It has been found also that the fragmentary pieces of lateral graphitic layer in the Carbon Nanofiber array resulted in substantial worsening of the quality of the Carbon Nanofibers. This might be one of the possible reasons why the measured EYM turned out to be much lower than the theoretical predictions reported in the literature. The measured EYM is also much lower than the reported in the literature atomic force microscopy (AFM)-based data for the EYM for multiwalled Carbon nanotubes (MWCNTs) that possess uniform and straight graphitic wall structure. Our transmission electron microscope (TEM) observations have revealed indeed poor structural qualities of the plasma-enhanced chemical vapor deposition (PECVD) grown CNFs.
Hongbin Cao - One of the best experts on this subject based on the ideXlab platform.
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self reduced vo vox Carbon Nanofiber composite as binder free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Yi Zhang, Kexin Tang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Self-reduced VO/VOx/Carbon Nanofiber composite as binder-free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Kexin Tang, Yi Zhang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
Zisheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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self reduced vo vox Carbon Nanofiber composite as binder free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Yi Zhang, Kexin Tang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.
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Self-reduced VO/VOx/Carbon Nanofiber composite as binder-free electrode for supercapacitors
Electrochimica Acta, 2016Co-Authors: Kexin Tang, Yi Zhang, Hongbin Cao, Zisheng Zhang, Jun YangAbstract:Abstract In this work, a free-standing, flexible and highly conductive vanadium-Carbon Nanofiber composite has been fabricated as electrode for Supercapacitors. Vanadium monoxide (VO) coupled with amorphous vanadium covalent bonds (VO x ) are successfully incorporated into Carbon Nanofibers (VO/VO x /CNF) by electrospinning and heat treatment. A theoretical explanation is proposed for the formation of VO/VO x in CNF composites. The VO and VO x are respectively reduced and formed from vanadium precursors of vanadium dioxide (VO 2 ) and vanadyl (IV) acetylacetonate (VOA) by means of self-reduction method, in which Carbon precursors (polyacrylonitrile and polyvinylpyrrolidone), small evolved gas molecules (CO, H 2 , HCN) and graphitized Carbon act as self-reductants. No additional reductants is needed before or after heat treatment, avoiding the secondary contamination. The VO/VO x /CNF electrode has a specific capacitance of 325.7 F g −1 at a current density of 1 A g −1 and is capable of reserving 92% of its initial capacitance after 5000 cycles operating at a current density of 4 A g −1 in a symmetric two-electrode capacitor using 6 M KOH as an electrolyte. The superior electrochemical performance of VO/VO x /CNF may be attributed to two advantages. The first is the enhanced conductivity brought upon the incorporation of quasi-metallic VO (∼ 10 2 Ω −1 cm −1 ) and the network of nanowire, and the second is the rapid ion transfer rate caused by the rich vanadium redox couples VO/VO x and the well-developed pore structure. Notably, this work has also provided a facile method to obtain varaible low valence states from vanadium oxides through self-reduction, which may also be applied to synthesize other metal oxides-Carbon Nanofiber composites.