| It is well known that solving the energy problem is the most important problem in thesociety nowadays,and the countries all over the world have made unremitting efforts to solve the energy problem.As a kind of clean,efficient and sustainable green energy,battery has been paid more and more attention.The Ni-Zn secondary battery we studied accords with the concept of sustainable development because it has many advantages: high power density,high working voltage,high safety index,no memory effect and low production cost.Therefore,nickel-zinc secondary battery has been widely studied,while nickel zinc secondary battery has not been widely used because of some problems,such as dendrite problem,zinc anode deformation,poor cycling performance and so on.On the basis of a systematic review of the research work on nickel zinc batteries and zinc anode materials at home and abroad,this paper starts from the angle of reducing the solubility of zinc oxide in alkaline electrolyte and increasing its cycle life.Physical mixing of zinc oxide with carbon materials(monolayer graphene,single-walled carbon nanotubes)by direct mechanical stirring,chemical synthesis of zinc oxide fillers,zinc oxide graphene composites and theoretical study on porous carbon filled with Zn O have been used to improve the performance of Ni-Zn battery.The physical mixed materials and chemical synthetic negative electrode materials are studied in detail.The composite state of zinc oxide and the morphology of zinc oxide before and after charge-discharge reaction were systematically analyzed by means of infrared spectrum X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscopy(TEM).The performance of Ni-Zn battery with different physical mixing ratio of zinc oxide to graphene monolayer is studied.The results of simulation show that the best cycle life and charge-discharge performance of Ni-Zn battery are obtained when the mass ratio of graphene to zinc oxide is 1: 4.19.The cycle life can reach 10000 times,and the battery performance is relatively poor in the first 2000 cycles,and the battery performance is maintained at a higher level after 2000 cycles.When the cutoff voltage is 0.2V,the maximum discharge specificcapacity is 2096 m Ah/g,and the capacity attenuation rate is only 0.0011%.We estimate that this is related to the performance of graphene capacitors.At the same time,in the process of synthesizing zinc oxide filled single-walled carbon nanotubes,a certain amount of concentrated nitric acid,single-walledcarbon nanotubes and zinc nitrate were mixed evenly.The single-walled carbon nanotubes were oxidized by the strong oxidization of concentrated nitric acid,the end cap of the carbon nanotubes was opened,zinc nitrate got into the inner wall of carbon nanotubes under the condition of heating reflux at 140?for 9h,and zinc nitrate filled with carbon nanotubes was obtained.Then zinc nitrate was decomposed in carbon nanotubes by vacuum heating to obtain zinc oxide carbon nanotube filling material.The mass fraction of zinc oxide in the filling material was calculated by thermogravimetry.In order to show the properties of the filling materials more clearly,the experiments of carbon nanotubes with the same proportion of zinc oxide were carried out,and the results were compared.The filling material greatly reduces the dissolution of zinc oxide in the charge / discharge cycle and effectively increases the cycle life of the battery to more than 600 cycles and greatly increases the capacity of the Ni-Zn battery.Porous carbon composite technology is an important method to improve and improve the electrochemical performance of electrode active materials.The main steps are the synthesis of precursors,pore making and controlling pore size,and in situ synthesis of supported zinc oxide.To improve the battery charging and discharging voltage platform and electrochemical cycle stability. |
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