Synthesis And Characterization Of Vanadium Oxide/Carbon Nanocomposites Applied To Supercapacitors

As a member of the energy storage and conversion devices,supercapacitors play an extremely important role in process of dealing with the severe energy shortage crisis.They possess significant merits of high power density,long cycle life and environmental friendliness.Vanadium oxides have become promising supercapacitor electrode materials due to their layered structure and high specific capacitance,while disadvantages of relatively poor conductivity and short cycling lifespan have limited their further development.Possessing unique disadvantages of low impedance and high stability,carbon materials can be introduced vanadium oxides to realize the functional complementation.Herein,in this work,three different vanadium oxides/carbon nanocomposites were prepared through facile hydrothermal process.Composition,structure and morphology of the products were characterized by XRD,FT-IR,Raman,BET,SEM and TEM tests.Electrochemical performances were evaluated by CV,GCD and EIS tests.The results are showed as following:V₂O₃@C core-shell nanorods with porous structures and large specific surface area were synthesized using V₂O₅ as the source of core and glucose as the source of shell by a facile hydrothermal route combination of heat treatment.The initial specific capacitance of V₂O₃@C was 228 F·g^-11 at the current density of 0.5 A·g^-1.Asymmetric supercapacitor device assembled from V₂O₃@C and activated carbon showed specific capacitances of 0.297 F·cm^-2 at 0.5mA·cm^-2.A capacitance retention of 86%for V₂O₃@C//C device after 1000 cycles indicated that V₂O₃@C had good cycling performance for supercapacitor application.HV_xO_y/rGO nanocomposite with a three-dimensional hierarchical porous structure and high specific area was prepared by a one-step facile hydrothermal method using starting materials of V₂O₅ and GO.It possessed special morphology of V₃O₇·H₂O/V₁₂O₂₆ nanobelts homogeneously attached on both sides of the soft and flexible rGO nanosheets.The effect of rGO content on nanocomposites'electrochemical performances was discussed.The HV_xO_y/rGO nanocomposite exhibited a high specific capacitance of 813 F·g^-1 at 0.5 A·g^-1,which was one of the highest values of similar materials in the literatures and extremely prominent cycle stability?93%capacitance retention after 10,000 cycles?.V₃O₇·H₂O/CNT/rGO ternary nanocomposite with a three-dimensional hierarchical porous structure and high specific area was prepared by a one-step facile hydrothermal method using starting materials of V₂O₅,CNT and GO.It possessed special morphology of V₃O₇·H₂O nanobelts and CNT homogeneously entirely covering on both sides of the soft and flexible rGO nanosheets.The effects of CNT and rGO content on nanocomposites'electrochemical performances were discussed.The V₃O₇·H₂O/CNT/rGO ternary nanocomposite exhibited a high specific capacitance of 685 F·g^-1 at 0.5 A·g^-1,which was one of the highest values of similar materials in the literatures and extremely prominent cycle stability?99.7%capacitance retention after 10,000 cycles?.