| As the development of human society and technology, our life has greatlyimproved. At the same time, it becomes to be a serious problem that short of energy.In order to solve the energy problem, on the one hand new and renewable energy areunder search; on the other hand, the existing energy shortage and transportation. It issolved the problem of energy uneven distribution in time and space when energyshortage materials appeared. So, it plays a vital role in sustainable development ofhuman society. Commonly used energy storage equipmentsare mainly for thepredominantly secondary battery and supercapacitor. It’s difficult to meet the demandof energy storage when the enhancement of the electronic products performance.Although the power battery energy storage is relatively higher than supercapacitor, ithas a poor performance in power, short service life, long charging time and otherdefects. On the opposite, supercapacitor has quick charge and discharge, large power,the advantages of good circulation, just can make up for the shortage of thebattery.But the supercapacitor energy storage density is low, how to further improvethe storage performance of super capacitor has become a key issue in the research.The present electrode materials, ruthenium oxide has good storage performance,but the raw material scarce, expensive, thereby limiting the application scope ofruthenium oxide.Compared to the ruthenium oxide, source widely materials such asmanganese oxide, cobalt oxide, nickel oxide although has certain store electricalenergy, but because of internal resistance is too large, the reservoir performance ispoorer, there is a certain distance as supercapacitor energy storage material ofalternative ruthenium oxide.As a result of ideal graphene has good electrical properties, it comes to be possibleto solve the problem of the super capacitor storage performance is poor. Because thegraphene itself is more easily together and the theory of specific capacitance is nothigh, this making the application of graphene in super capacitor energy storagematerial is a certain limit.By adopting composite with other materials, the method of graphene based composite material can be, so as to improve the reservoirperformance.In this paper, the nanometer zinc oxide and nanometer zincoxide/graphenecomposites were prepared by hydrothermal method, from the raw material cost,processing technology, environmental friendliness, and stability of materials, such asmultiple perspectives to consider. Based on previous research, it is focused on theinfluence of different solvent environment such as water, water/ammonia, ethanoland ethanol/water on the preparation the nanometer zinc oxide and nanometerzincoxide/graphene composites.The products were by analysis and testing by the Xray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM),thermal gravimetric (TG)analysis. To make nanometer zincoxide/graphenecomposites into the super capacitor, and the electrical testing cyclic voltammetry, theconstant DC charging and discharging and AC impedance spectra and cyclic stabilitywere analyzed and tested.In this paper, the main conclusions are as follows:The nano zinc oxide particles are prepared by using solvent hot method withNaOH and Zn(Ac)2·2H2O as the main raw materials, and ethanol as solvent, and themixture solvent is configurated and diluted gradually. It’s showed that the nano zincoxide particles have a hexagonal structure, high crystalline, good dispersion, andrelatively uniform particle size. The average particle diameter of the nano zinc oxideparticlesare6.69nmcalculated by the Scherrer formula.The nano zinc oxide rods are prepared by taking solvent thermal method withNaOH and Zn(Ac)2·2H2O and ethanol as the main raw materials, the sodiumhydroxide solution was gradually added dropwise to the configuration of the zincacetate solution. It’s showed that the nano zinc oxide rods have a hexagonal structure,high crystallinity, good dispersion, and relatively uniform rods size. The averagelength of rods is about1μ m, the average diameter is about40nm, and the rod lengthdiameter ratio is25:1.The supercapacitor electrode materials are made with rod-shaped nano zincoxide/graphene composites for active substances, with acetylene black as conductiveagent, with poly vinylidene fluoride (PVDF) as the binder. It will be assembled into asupercapacitor. After assembled, it was investigated by cyclic voltammetry, constantcurrent charge discharge, alternating straight impedance analysis, cyclic stability test.The result showed that its specific capacitance is reached260F/g, and it’shigher thanbothgraphene specific capacitance (120F/g) and Zinc Oxide specific capacitance(100F/g).So both of zinc oxide and grapheme has played a positive synergistic effect..After500cycles of charge and discharge specific capacity, it is maintainedafter maximal ratio capacity of91.5%.It show that this material has good cyclestability.In this paper, nano zinc oxide was prepared by one step method. On the basis ofmethod, the raped nano zinc oxide/graphene composites withthe good charge storageproperties were prepared. The preparation method has the cheap raw material, simpleprocess and the characteristics of the product of uniform morphology. This study forthe preparation of graphene electrode material provides a new thought and method, toimprove the storage performance of supercapacitor electrode material provides a newpath. |
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