Research On Anode Materials For Zinc-nickel Secondary Batteries

Since the 21 century,the issues of environment and resources have been the focus of attention all over the world.With the gradual shortage of petroleum resources,the future society will become a new energy development strategy as the center.Therefore,with the development of society,a new generation of energy storage devices with non-pollution,high safety performance,low production cost,high energy density and high power is urgently needed to replace the power battery used in traditional energy vehicles.Zn-Ni battery is a kind of alkaline battery with high specific energy(50⁸0Wh·kg^-1),high specific power(500 W·kg^-1),high working voltage?1.2¹.5 V?,high open circuit voltage?1.75 V?,environmental protection and no memory effect.However,the negative electrode of Zn-Ni battery will produce problems such as deformation,dendrite,self-corrosion and passivation during charging and discharging,which reduces the cycle life of the electrode and affects the industrialization development of Zn-Ni battery.For this reason,the following research work has been carried out in this paper:zinc oxide coated with Sn₆O₄?OH?₄,Zn-Al-hydrotalcites,hexagonal calcium zincate?Ca?OH?₂·2Zn?OH?₂·2H₂O?have been prepared for zinc-nickel batteries.The prepared materials were characterized and tested by the scanning electron microscope?SEM?,X-ray diffraction?XRD?,electrochemical impedance spectroscopy?EIS?,energy spectrum measurement?EDS?,particle size analysis,electrochemical impedance spectroscopy,cyclic voltammetry?CV?,polarization curves and constant current charge-discharge test.Zinc oxide coated Sn₆O₄?OH?₄ was prepared by hydrothermal-coprecipitation method.It was found that Sn₆O₄?OH?₄ could adhere to the surface of ZnO particles under the condition of pH=12 and the crystal structure was better,and the coating Sn₆O₄?OH?₄ on ZnO surface had good reversibility.It can improve the corrosion resistance of zinc anode and reduce the internal resistance.when the zinc electrode covered with Sn₆O₄?OH?₄ amount of 3%,It is found that its electrochemical performance and the charge and discharge performance are better,and the cyclic stability is more stable than that of the traditional zinc oxide electrode.It is showed that the discharge capacity is 70%after 40 cycles through the charge-discharge test at0.2 CZn-Al-hydrotalcitesanodematerialswererespectivelysynthesizedby hydrothermal method and co-precipitation method.The differences of morphology,structure and particle size of zinc-aluminum hydrotalcite prepared by two preparation methods were studied.The differences between two kinds of zinc aluminum hydrotalcites and zinc oxide electrode were compared by electrochemical test,it is found that The internal resistance,cyclic voltammetry,electrode capacity and corrosion resistance of zinc aluminum hydrotalcite electrode were better than ZnO,and The Zn-Al-hydrotalcites prepared by hydrothermal method is the best one.The charge-discharge test of Zn-Al-hydrotalcites electrode shows that the cyclic performance is stable,the retention rate is high,and the discharge specific capacity is larger.It is also found that the retention rate of Zn-Al-hydrotalcites electrode prepared by hydrothermal method is 81.4%after 40 cycles at 0.2 C.Hexagonal calcium zincate was prepared by hydrothermal method for zinc nickel battery.The phase analysis shows that the prepared calcium zincate has hexagonal structure,uniform dispersion and good crystallinity.the corrosion resistance and reversibility of hexagonal calcium zincate are obvious better than ZnO through electrochemical.It was found that the corrosion resistance,reversibility and internal resistance of hexagonal calcium zincate were better than that of zinc oxide electrode,and the charge-discharge test showed that the retention rate of calcium zinc oxide electrode was 86.28%after 40 cycles at 0.2 C.Through the study of three kinds of negative electrode materials,it is found that the properties of these materials are superior to those of ordinary pure zinc oxide.After40 cycles,the cycle retention rate of zinc oxide coated with Sn₆O₄?OH?₄ is 70%,and the cycle retention rate of Zn-Al-hydrotalcites?81.4%?is lower than that of alcium zinc oxide?86.28%?.