| The state explicitly proposed to increase the proportion of clean energy in the“Thirteenth Five-Year Plan”.Electric energy,as a typical representative of energy,is flexible and green.The flexible and efficient storage and use of electrical energy has promoted the tremendous development of energy storage devices such as new batteries,super capacitors.Among them,the introduction of nanomaterials has given rise to many advantages of supercapacitors,such as rapid high current charge and discharge,high energy density and power density,long cycle life,and no pollution to green,which plays a key role in the development of supercapacitor electrode materials.Due to the multivalent state of vanadium,redox reactions can occur,and the layered structure of vanadium oxides can easily allow ions to intercalate and desorb.Therefore,the application of vanadium oxides in the field of electrochemical energy storage has been a research hotspot.Based on this background,the graduation thesis synthesizes vanadium pentoxide-based nanomaterials using cheap ammonium vanadate and hydrochloric acid as row materials,glucose as carbon source additive and polyvinylpyrrolidone as blocking agent through simple hydrothermal method.The effects of reaction time,carbon source concentration,capping agent dosage and other conditions in phase composition and microscopic characteristics are studied.And then the optimized process parameters for the preparation of vanadium pentoxide based nanomaterials are determined.The optimum preparation parameters of vanadium pentoxide nanoribbons are the hydrothermal reaction temperature 160oC and the reaction time 24h.When adding glucose as carbon source,the optimal conditions for the preparation of vanadium pentoxide/carbon nanobelts by hydrothermal method are reaction temperature 160oC,reaction time 4h and glucose 1.70*10-2M.As polyvinylpyrrolidone-K30 is used as a capping agent,the vanadium pentoxide quantum dots are gained with the optimum preparation parameters,160oC,24h and 1.70*10-4M agent.After successful preparation of vanadium pentoxide-based nanomaterial and gaining the optimum synthetization parameters,the electrochemical properties of the as-attained production are studied by AUTOLAB in 0.5mol/L Na2SO4 aq and Ag/AgCl as reference electrode,Pt as counter electrode.When the scan rate is 5 mV/s,vanadium pentoxide nanobelts electrode expresses 82.65F/g specific capacitance by cyclic voltammetry while the vanadium pentoxide/carbon nanobelts`is 127.27F/g and the vanadium pentoxide quantum dots`is 88.78F/g.In the same time,when the current density is 0.25A/g,the specific capacitances obtained from charge and discharge point is 159.40F/g,219.25F/g and 96.48F/g for vanadium pentoxide nanobelts,vanadium pentoxide/carbon nanobelts and vanadium pentoxide quantum dots,respectively. |
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