Preparation and application of zinc oxide-based hydrated cerium carbonate composite material

Abstract

The application discloses a preparation method and application of a zinc oxide-based hydrated cerium carbonate oxide composite material, in particular to a preparation method and application of a Ce2O(CO3)2H2O / ZnO composite material, wherein the preparation method comprises the following steps: preparing a salt solution, preparing an alkali solution, ultrasonic mixing of the salt solution and the alkali solution, pH adjustment, aging, washing and drying of the product; the method provided by the application is used for preparing a zinc-nickel battery negative active material and inhibiting the growth of dendrites; compared with physical mixing, the hydrothermal method can effectively control the reaction and the crystal growth by changing the temperature, the pressure and the reaction time, so that the Ce is better grown on the surface of the ZnO, and the Ce2O(CO3)2H2O / ZnO composite material with better crystallinity is generated; the Ce2O(CO3)2H2O / ZnO composite material prepared by the method has a larger specific surface area and higher catalytic activity compared with traditional ZnO.

Description

Technical Field

[0001] This invention belongs to the field of new energy battery technology, specifically relating to the preparation of Ce2O(CO3)2Hּ2O / ZnO (zinc oxide-based hydrated cerium oxycarbonate) composite material and its application in zinc-nickel batteries. Background Technology

[0002] Compared with lead-acid batteries, zinc-nickel batteries, as a new type of energy battery, have advantages such as high operating voltage, high specific energy, high safety, low cost, fast charging and discharging, and good environmental performance. They also have no memory effect and can meet the requirements of high-current discharge, making them an ideal replacement for lead-acid batteries. Currently, the negative electrode material of zinc-nickel batteries is mainly ZnO. However, after dozens of charge-discharge cycles, ZnO exhibits significant dendrite growth. With increasing cycle count, the dendrites further grow and puncture the separator, causing battery failure. Compared with ZnO, adding rare earth elements with high hydrogen evolution overpotential can inhibit dendrite growth to some extent (Reference: Fan X, Yang Z, Long W. The preparation and electrochemical performances of the composite materials of CeO2 and ZnO as a node material for Ni-Zn secondary batteries[J]. Electrochimica Acta, 2013, 108:741-748). As can be seen from the existing patent "A method for growing zinc oxide single crystals using hydrothermal method" (patent number CN200410009367.6), the preparation cycle of the zinc oxide single crystals described in this patent is relatively long, the production cost is relatively high, and the product's electrochemical performance and application in zinc-nickel batteries have not been studied. The existing patent "A method for preparing uniformly sized nano-hydrated cerium oxycarbonate" (patent number CN201811561803.9) requires a secondary pH adjustment during the preparation of hydrated cerium oxycarbonate, making the preparation process relatively complex. Summary of the Invention

[0003] The method provided in this invention prepares anode active materials for zinc-nickel batteries and inhibits dendrite growth. Compared with physical mixing, the hydrothermal method can effectively control the reaction and crystal growth by changing the temperature, pressure, and reaction time, allowing Ce to grow better on the ZnO surface and generating a Ce2O(CO3)2H₂O / ZnO composite material with better crystallinity. The Ce2O(CO3)2H₂O / ZnO composite material prepared by this method has a larger specific surface area and higher catalytic activity compared with traditional ZnO. It can produce a high-purity Ce2O(CO3)2H₂O / ZnO composite material with fewer defects that inhibits zinc dendrite growth in the anode, and this material exhibits superior electrochemical performance in zinc-nickel batteries.

[0004] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution:

[0005] The preparation method of Ce2O(CO3)2H₂O / ZnO composite material includes the following steps:

[0006] S1: Mix zinc nitrate and cerium nitrate evenly at a molar ratio of zinc ions to cerium ions of 3:0.75, and then add deionized water to prepare a salt solution.

[0007] S2: Mix sodium hydroxide and anhydrous sodium carbonate according to the formula nNaOH=2(nZn 2+ +nCe 3+ ), nNa2CO3=2nCe 3+ The molar ratios are mixed evenly, and then deionized water is added to prepare an alkaline solution.

[0008] S3: Sonicate the salt solution and alkaline solution obtained from S1 and S2 for 10 min each, then let them stand.

[0009] S4: Add deionized water to the container as the base solution. Under water bath conditions, slowly add the ultrasonically settled salt solution and alkali solution dropwise into the base solution while stirring. Control the pH value at 9.5~10.5. After the reaction is complete, continue stirring for 1 hour.

[0010] S5: The reaction product obtained in S4 is aged in a hydrothermal reactor for 10-12 hours. After aging, it is taken out and washed with alcohol and deionized water 3-5 times.

[0011] S6: Dry the reaction product obtained in S5 in a drying oven for 10-12 hours to obtain Ce2O(CO3)2Hּ2O / ZnO composite material;

[0012] Preferably, the water bath temperature in step S4 is 60°C; the salt solution and alkali solution are slowly dripped into the base liquid using a peristaltic pump;

[0013] Preferably, the aging temperature in the hydrothermal reactor in step S5 is 120°C, and the drying temperature in the drying oven in step S6 is 60°C.

[0014] Preferably, the zinc nitrate and cerium nitrate are Zn(NO3)26H2O and Ce(NO3)36H2O; the Ce2O(CO3)2H2O / ZnO composite material is used in zinc-nickel battery electrode materials;

[0015] Another object of the present invention is to provide a method for applying the Ce2O(CO3)2H₂O / ZnO composite material:

[0016] A Ce2O(CO3)2Hּ2O / ZnO composite material with good crystallinity was mixed with zinc powder, acetylene black, sodium carboxymethyl cellulose (CMC), and polytetrafluoroethylene (PTFE) in a mass ratio of 80:6:5:4:5 as the negative electrode active material of the zinc-nickel battery. The mixture was pressed into a 1cm×1cm working electrode, with sintered nickel as the positive electrode and a 6mol / L saturated zinc oxide KOH solution as the electrolyte. The zinc-nickel battery was assembled in an acrylic glass outer packaging.

[0017] The beneficial effects of this invention are:

[0018] The method for preparing Ce₂O(CO₃)₂H₂O / ZnO composite materials according to this invention is simple and easy to operate, facilitating large-scale production. Compared with traditional physical mixing methods, the hydrothermal method enables rare earth elements to grow onto the ZnO surface, resulting in Ce₂O(CO₃)₂H₂O / ZnO composite materials with better crystallinity. The hydrothermal method allows for control of the reaction process, as well as the shape and growth direction of the grains, by adjusting temperature, pressure, and reaction time—something difficult to achieve with physical mixing methods. The Ce₂O(CO₃)₂H₂O / ZnO composite material prepared by this invention exhibits higher electrochemical activity and a longer cycle life compared to zinc-nickel battery anode active materials prepared by traditional methods, expanding the selection of zinc-nickel battery anode active materials and providing guidance for the development of novel metal secondary batteries. Attached Figure Description

[0019] Figure 1 This is the XRD pattern of the Ce2O(CO3)2H₂O / ZnO composite material prepared in Example 1 of this invention;

[0020] Figure 2a 2b is a scanning electron microscope image of the Ce2O(CO3)2Hּ2O / ZnO composite material prepared in Example 1 of this invention;

[0021] Figure 3 These are the cyclic voltammetry curves of the Ce2O(CO3)2Hּ2O / ZnO composite material prepared in Example 1 and pure ZnO. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0023] The preparation method of Ce2O(CO3)2H₂O / ZnO composite material, and its specific steps are as follows:

[0024] S1: Mix 0.09 mol zinc nitrate and 0.0225 mol cerium nitrate thoroughly, then add deionized water to prepare a salt solution, and then add 70 ml of deionized water to prepare another salt solution. Mix 0.225 mol sodium hydroxide and 0.045 mol anhydrous sodium carbonate thoroughly, then add 70 ml of deionized water to prepare an alkaline solution.

[0025] S2: Sonicate the salt solution and alkali solution in S1 for 10 minutes each, then let them stand.

[0026] S3: Place a three-necked flask in a water bath and add a certain amount of bottom liquid. Maintain the water bath temperature at 60°C. Use two peristaltic pumps to slowly drip the salt solution and alkali solution from S2 into the bottom liquid of the three-necked flask while adding and stirring. Control the pH of the reaction system to around 10. After the reaction is complete, continue stirring for 1 hour.

[0027] S4: The sample obtained in S3 was aged in a hydrothermal autoclave at 120℃ for 12 hours. After being taken out, it was washed with alcohol and deionized water 3 to 5 times.

[0028] S5: The sample obtained in S4 was dried in an oven at 60℃ for 12h to obtain Ce2O(CO3)2Hּ2O / ZnO composite material;

[0029] The XRD pattern and scanning electron microscope image of the prepared Ce2O(CO3)2H₂O / ZnO composite material are shown below. Figure 1 And as shown in Figure 2. From Figure 1 As can be seen from Figure 2, characteristic diffraction peaks appear near 20.44°, 23.88°, 26.67°, 30.37°, and 38.33°, which coincide with the theoretical diffraction peak positions of Ce₂O(CO₃)₂H₂O. Similarly, characteristic diffraction peaks appear near 31.74°, 34.39°, 36.23°, 47.52°, and 56.55°, which coincide with the theoretical diffraction peak positions of ZnO. Figure 2 shows that Ce₂O(CO₃)₂H₂O was successfully grown on the ZnO surface in the prepared material, and the crystallinity is good.

[0030] Application methods of Ce2O(CO3)2H₂O / ZnO composite materials:

[0031] A Ce₂O(CO₃)₂H₂O / ZnO composite material with good crystallinity was mixed with zinc powder, acetylene black, CMC, and PTFE in a mass ratio of 80:6:5:4:5 as the negative electrode active material for zinc-nickel batteries. A copper mesh was used as the current collector, and the mixture was pressed into a 1cm × 1cm working electrode. After the electrode dried, cyclic voltammetry was performed using a Metrohm PGSTAT302N electrochemical workstation. The test employed a three-electrode system: a platinum electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a copper mesh electrode loaded with the Ce₂O(CO₃)₂H₂O / ZnO composite material as the working electrode. The electrolyte was a 6mol / L saturated zinc oxide KOH solution. The cyclic voltammetry scan potential window was -1.2 to -1.9 V, and the scan rate was 20 mV / s⁻¹. The cyclic voltammetry curve of the Ce₂O(CO₃)₂H₂O / ZnO composite material prepared in this example is shown below. Figure 3 As shown, from Figure 3 It can be seen that the peak areas of the reduction and oxidation peaks are much larger than those of pure ZnO, indicating that the prepared Ce2O(CO3)2Hּ2O / ZnO composite material has better cycle reversibility, and can achieve better electrochemical performance when used as the negative electrode active material of zinc-nickel battery. Example 2

[0032] The preparation method of Ce2O(CO3)2H₂O / ZnO composite material, and its specific steps are as follows:

[0033] S1: Mix 0.18 mol zinc nitrate and 0.045 mol cerium nitrate evenly, then add 70 ml of deionized water to prepare a salt solution; mix 0.45 mol sodium hydroxide and 0.09 mol anhydrous sodium carbonate evenly, then add 70 ml of deionized water to prepare an alkaline solution;

[0034] S2: Sonicate the salt solution and alkali solution in S1 for 10 minutes each, then let them stand.

[0035] S3: Place a three-necked flask in a water bath and add a certain amount of bottom liquid. Maintain the water bath temperature at 60°C. Use two peristaltic pumps to slowly drip the salt solution and alkali solution from S2 into the bottom liquid of the three-necked flask while adding and stirring. Control the pH of the reaction system to around 10. After the reaction is complete, continue stirring for 1 hour.

[0036] S4: The sample obtained in S3 was aged in a hydrothermal autoclave at 120℃ for 12 hours. After being taken out, it was washed with alcohol and deionized water 3 to 5 times.

[0037] S5: The sample obtained in S4 was dried in an oven at 60℃ for 12h to obtain Ce2O(CO3)2Hּ2O / ZnO composite material. Example 3

[0038] The preparation method of Ce2O(CO3)2H₂O / ZnO composite material, and its specific steps are as follows:

[0039] S1: Mix 0.045 mol zinc nitrate and 0.01125 mol cerium nitrate thoroughly, then add deionized water to prepare a salt solution, and then add 70 ml of deionized water to prepare another salt solution. Mix 0.315 mol sodium hydroxide and 0.0225 mol anhydrous sodium carbonate thoroughly, then add 70 ml of deionized water to prepare an alkaline solution.

[0040] S2: Sonicate the salt solution and alkali solution in S1 for 10 minutes each, then let them stand.

[0041] S3: Place a three-necked flask in a water bath and add a certain amount of bottom liquid. Maintain the water bath temperature at 60°C. Use two peristaltic pumps to slowly drip the salt solution and alkali solution from S2 into the bottom liquid of the three-necked flask while adding and stirring. Control the pH of the reaction system to around 10. After the reaction is complete, continue stirring for 1 hour.

[0042] S4: The sample obtained in S3 was aged in a hydrothermal autoclave at 120℃ for 12 hours. After being taken out, it was washed with alcohol and deionized water 3 to 5 times.

[0043] S5: The sample obtained in S4 was dried in an oven at 60℃ for 12h to obtain Ce2O(CO3)2Hּ2O / ZnO composite material.

Claims

1. A method for preparing Ce2O(CO3)2H2O / ZnO composite material, characterized in that, Includes the following steps: S1: Mix zinc nitrate and cerium nitrate evenly at a molar ratio of zinc ions to cerium ions of 3:0.75, and then add deionized water to prepare a salt solution. S2: Mix sodium hydroxide and anhydrous sodium carbonate according to the formula nNaOH=2(nZn 2+ +nCe 3+ ), nNa2CO3=2nCe 3+ The molar ratios are mixed evenly, and then deionized water is added to prepare an alkaline solution. S3: Sonicate the salt solution and alkaline solution obtained from S1 and S2 for 10 min each, then let them stand. S4: Add deionized water to the container as the base solution. Under water bath conditions, slowly add the ultrasonically settled salt solution and alkali solution dropwise into the base solution while stirring. Control the pH value between 9.5 and 10.

5. After the reaction is complete, continue stirring for 1 hour. S5: The reaction product obtained in S4 is aged in a hydrothermal reactor for 10-12 hours. After aging, it is taken out and washed with alcohol and deionized water 3-5 times. S6: The reaction product obtained in S5 is dried in a drying oven for 10-12 hours to obtain Ce2O(CO3)2H2O / ZnO composite material; The aging temperature in the hydrothermal reactor in S5 is 120℃, and the drying temperature in the drying oven in S6 is 60℃.

2. The preparation method of the Ce2O(CO3)2H2O / ZnO composite material according to claim 1, characterized in that, The water bath temperature in S4 is 60°C; a peristaltic pump is used to slowly drip the salt solution and alkali solution into the base liquid.

3. The preparation method of the Ce2O(CO3)2H2O / ZnO composite material according to claim 1, characterized in that, The zinc nitrate and cerium nitrate are Zn(NO3)2·6H2O and Ce(NO3)3·6H2O, respectively.

4. The method for preparing the Ce2O(CO3)2H2O / ZnO composite material according to any one of claims 1 to 3, characterized in that, The application of the prepared Ce2O(CO3)2H2O / ZnO composite material in zinc-nickel battery electrode materials is disclosed.

5. The application of the Ce2O(CO3)2H2O / ZnO composite material according to claim 4, characterized in that, This can be achieved in the following ways: A Ce2O(CO3)2H2O / ZnO composite material with good crystallinity was mixed with zinc powder, acetylene black, CMC and PTFE in a mass ratio of 80:6:5:4:5 as the negative electrode active material of zinc-nickel battery. The mixture was pressed into a 1cm×1cm working electrode, with sintered nickel as the positive electrode and a 6mol / L saturated zinc oxide KOH solution as the electrolyte. The zinc-nickel battery was assembled in an acrylic glass outer packaging.

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