Preparation and Electrochemical Performance of Calcium Zinc Calcium

Preparation and Electrochemical Performance of Zinc Calcium Yu Jingxian, Yang Hanxi, Zhu Xiaoming, Ai Xinping (School of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei, China) was confirmed and studied using powder microelectrodes, analog cell technology and XRD technology. Cyclic voltammetric characteristics of the compound, charge and discharge behavior, and changes in the morphology of the material during charge and discharge. The experimental results show that the calcium zincate in the alkaline solution shows a significantly better cycle performance than the ZnO and zinc-calcium mixture, and the charged product is metal zinc. The zinc-nickel battery, which is used as a negative electrode active material, has been currently recycled more than 500 times, and no significant deterioration of the battery capacity has occurred.

The secondary zinc electrode research boom began in the 1970s. 1. To summarize and summarize the research results of improving the life cycle of zinc poles. These methods improve the deformation of secondary zinc electrodes. The dendritic and extended electrode cycle life is helpful, but the scope of application is still limited. This article chemically synthesized calcium zincate as the negative electrode material of the battery and tested the structure of the compound. Thermal stability and electrochemical performance.

1 Experiment 1.1 Preparation of calcium zincate 50 g of analytically pure Ca(OH)2 powder was slowly added to 500 ml of ZnO-saturated 4 mol/L KOH solution at room temperature under continuous stirring, and 73 ml of distilled water was added and slowly added. 109.8 g of analytically pure ZnO powder.

In order to disperse and mix the powder uniformly in the solution, stirring was continued for 72 hours and the mixture was allowed to stand still for 60 hours to allow the newly formed compound crystals to age and grow in the reaction.

The supernatant was decanted and the white precipitate was washed with distilled water to a pH of approximately 7.2 with a scanning electron microscope. Thermal Analysis and X-Ray Diffraction Analysis The newly prepared calcium zincate was dried at 50° C. for 2 h and then sprayed with gold to enhance the conductivity and then the surface morphology of the sample was observed. Thermogravimetry (TG) and differential thermal analysis (DTA) experiments were performed on a WCT-1A microcomputer differential thermogravimetry at a heating rate of 10°C/min. Powder X-ray diffraction analysis was performed using a D/MAXU1B powder diffractometer, Cu Target K accelerating voltage 30kV, current 300mA, scanning speed 5°/min. Yu Jingxian (1971―), male, Hanchuan, Hubei, Wuhan University lecturer, Ph.D., mainly engaged in electrochemical research; Yang Hanxi (1955 -), male, Hubei Wuhan Ren, Professor and Ph.D., Wuhan University, mainly engaged in high-energy electrochemical system research; Zhu Xiaoming (1972―), male, Xianning, Hubei, doctoral student of Wuhan University, mainly engaged in electrochemical research; Ai Xinping (1968―), male , Hubei Xiantao People, Associate Professor and Ph.D., Wuhan University, is mainly engaged in high specific energy electrochemical system research.

SEM image of calcium lanthanum zincate powder Microelectrode Nickel plate counter electrode Organic glass bottom plate Electrolysis structure schematic The battery cathode uses a ready-made large-area sintered NiOOH chip. The apparent area of ​​the negative electrode is 16 cm2, and the mass of calcium zincate contained therein is 0.41 g. The experimental electrolyte is a ZnO-saturated 4 mo/L KOH solution, and the separator is two layers of alkali-resistant nylon non-woven fabric and polythiol placed in the middle. Phenolic separator. The charging and discharging cycle mechanism of the battery is as follows: 20mA constant current charging 240min, 20mA constant current discharging to 1.10V. The battery is hot-pressed and sealed by the aluminum-plated plastic film and circulated in the sealing state.

2 Results and discussion 1 Structural characterization and thermal stability study of calcium zincate Table 1 shows X-ray powder diffraction results of freshly prepared calcium zincate samples and their diffraction parameters with Ca(OH)2Zn(OH)2° The standard results of 2H2O were compared. From the results in the table, we can see that the spacing of the crystal planes of our synthesized powder material is quite consistent with the standard diffraction spectrum. This shows that the calcium zincate material we synthesized is a Ca(OH)2Zn(OH) with a monoclinic structure. ) 2° 2 H 2 O compound. However, the relative intensities of the sample diffraction peaks are quite different from those of the standard spectra. The reason for this phenomenon is that the preferred orientation of the crystal plane (200) reduces the relative diffraction intensity of other peaks. Similar phenomena have been reported in the 3丨. . A scanning electron micrograph of calcium zincate is shown with a magnification of 300K. It can be seen from the figure that the crystal structure of Ca(OH)2Zn (OHV2H2O is a monoclinic cell, and the apparent size of the unit cell can be roughly calculated to be 11mX11/m. Table 1 X-ray diffraction spectrum of freshly prepared calcium zincate. Comparison with standard spectra