Preparation And Supercapactitive Performance Of Vanadium Nitride/Carbon Nanocomposites

With the rapid development of global economy,the environment pollution and energy crisis are the pressing problems in front of people around the world.to the effective use of dean and renewable energy,the world has enormous internal demand for energy storage devices.Among various devices supercapacitor(SC)presents the popular direction in the field of energy storage Electrode material is the main component of supercapacitor,its composition and structure directly affect the energy storage potential of supercapacitor.Therefore the key to improve the storing energy performance of supercapacitor is to design new and effici ent electrode materi als Vanadi um nitride is the most widely studied typical electrode materials,but in actual applied to still exist the following problems:(1)Vanadium nitride shows high specific capacitance of theory,but in the process of practical application because of its utilization is lirrited,the actual low specific capacitance electrode materials(2)Vanadium nitride in different electrolyte presents different specific capacitance,high specific capacitance in alkaline electrolyte,but the electrochemical oxidation of dissolved in alkaline electrolyte,leading to poor circulation stability.In this paper,the design of high-performance vanadium nitride electrode material and its electrochemical performance in the application of supercapacitors are studied.The main research contents are as follows:1.The vanadium nitride/carbon nanofiber composites were prepared by hydrothermal method with vanadium pentoxide and melamine as the vanadium surce and carbon source respectively,and further heat treatment was carried out under N2 atmosphere The effects of vanadium content and carbonization temperature on the morphology and electrochemi cal performance of the VN/C composites electrode materi als were investigated.TheVN/C-0.5 exhibited a specific capacitance of 267 Fg-1 at 1 A g-1,and exceptional cycling stability(66.5%retention after 10000 cydes).2.Using melamine and armonium metavanadate as crude materials,vanadium nitride/carbon composites were prepared by hydrothermal method,and the effects of different raw material ratios and different carbonation temperatures on the morphology and electrochemical properties of the materials were investigated.The VN/C-0.45 exhibited a specific capacitanceof 300 F g-1 at 1 A g-1,and exceptional cycling stability(81.2%retention after 10000 cycles).3.Taking melamine as the carbon source and vanadium acetylacetonate as the vanadium source,after mechanical mixing,it was fully mixed and reacted under hydrothermal conditions Furthermore the coralIoid-like nanostructure vanadium nitride/carbon nanooorrposite was obtained by carbonization under nitrcgen atmosphere.The nanooorrposite,preliminary discussed the effects of different raw material ratio on the electrochemical properties and also studies the different temperature and atmosphere for vanadium nitride carbide carbide/carbon nanotube composite material structure the influence of the element composition and electrochemical performance The coralloid-like VN/C-0.35 exhibited a wide voltage window from-1.1 to 0 V,a higher specific capacitance of 385 Fg-1 at 1 A g-1 and 88.9%capacitance retention after 10000 cycles.An appropriate amount of VN evenly embedded in the carbon matrix can present the electrochemical oxidation of vanadium nitride in alkaline electrolyte,which promotes superior electrochemical perfprmance of VN/C.