Zinc ion battery negative electrode and preparation method and application thereof

Abstract

The invention particularly relates to preparation and application of a zinc ion battery negative electrode protection layer, and belongs to the technical field of zinc ion batteries. The specific preparation method comprises the following steps: (1) dissolving metal fluoride in deionized water or an organic solvent, and continuously carrying out sand bath until solute is completely dissolved, so as to prepare a mixed metal fluoride solution; (2) the metal fluoride solution is cooled and then used for soaking the zinc plate; and (3) taking out the zinc plate, cleaning with absolute ethyl alcohol, and drying for battery assembly and test. The preparation method has the advantages of simple operation, easily available raw materials and low cost. The negative electrode protection layer can effectively inhibit dendritic crystal growth caused in the charging and discharging process, and the cycle life of the battery is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc ion batteries, and in particular relates to a zinc ion battery negative electrode protective layer, a preparation method and an application thereof. Background Art

[0002] The conversion and utilization of renewable energy is becoming increasingly important. Benefiting from its environmental friendliness, inherent safety, and easy recycling, aqueous zinc-ion batteries have broad application prospects in the field of energy storage.

[0003] However, the commercial development of zinc-ion batteries has been hampered by numerous issues. Dendrite growth is a major concern in the zinc anode application of zinc-ion batteries, primarily due to uneven zinc ion deposition during charge and discharge. By creating a protective layer on the zinc anode to reduce direct contact between the anode and the electrolyte, this allows for uniform zinc deposition, thereby improving the battery's cycle life. Summary of the Invention

[0004] The present invention addresses the problem of dendrite growth in zinc ion batteries and provides a zinc ion battery negative electrode protective layer, a preparation method, and applications thereof. The preparation method is simple to operate, uses readily available raw materials, and is low in cost. The negative electrode protective layer of the present invention can effectively inhibit dendrite growth caused during charge and discharge, thereby extending the battery cycle life.

[0005] The technical solution of the present invention is a method for preparing a negative electrode protective layer of a zinc ion battery, and the specific steps are as follows:

[0006] The metal fluoride solution is prepared by dissolving the metal fluoride in deionized water or an organic solvent and continuing the sand bath until the solute is completely dissolved;

[0007] The metal fluoride solution is cooled and used to soak the zinc plate;

[0008] The zinc plate was removed and cleaned with anhydrous ethanol, and then dried for battery assembly and testing.

[0009] Preferably, the metal fluoride is one or more of indium fluoride, silver fluoride, copper fluoride, bismuth fluoride, and magnesium fluoride.

[0010] Preferably, the concentration of the metal fluoride solution is 0.5-2 mmol / L.

[0011] Preferably, the sand bath temperature is 60-80°C.

[0012] Preferably, the zinc plate is immersed for 3-5 minutes.

[0013] Preferably, the drying is vacuum drying at 50-60° C. for 6-8 hours.

[0014] Compared with the prior art, the technical solution of the present invention can achieve the following beneficial effects:

[0015] (1) The preparation method is simple to operate, the raw materials are easily available, and the cost is low.

[0016] (2) The zinc ion battery negative electrode protective layer of the present invention effectively reduces the direct contact between the negative electrode and the electrolyte, guides uniform zinc deposition, and inhibits dendrite growth, thereby improving the cycle life of the battery (confirmed by characterization methods such as SEM / FIB / SIMS / XPS / XRD). BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 The symmetrical battery assembled by the negative electrode protective layer of the zinc ion battery in Example 1 of the present application is 0.5mA / cm 2 Cycling curves at current density of . Figure 2 The symmetrical battery assembled in Comparative Example 1 of this application is 0.5 mA / cm 2 Cycling curves at current density of . DETAILED DESCRIPTION

[0017] The present invention is described in detail below by way of examples.

[0018] Example 1

[0019] (1) Place 0.0344 g of indium fluoride in a 250 mL flask and add 200 mL of deionized water to dissolve it. Place the flask in a sand bath and maintain the sand bath temperature at 80°C until the solute indium fluoride is completely dissolved to prepare a 1 mmol / L indium fluoride solution.

[0020] (2) After the indium fluoride solution is cooled to room temperature, it is used to soak the zinc plate for 10 minutes;

[0021] (3) The zinc plate was removed and cleaned with anhydrous ethanol. After vacuum drying at 60°C for 6 hours, a zinc negative electrode with a protective layer was obtained for battery assembly and testing. FIB, SIMS, and XPS characterization revealed that the InF3-treated zinc plate formed a layered adhesion layer on its surface. The concentrations of indium and fluorine gradually decreased from the outside to the inside of the zinc plate, forming a concentration gradient. XRD results also showed characteristic peaks for In, indicating that some indium formed an alloy with zinc. SEM analysis revealed that the InF3-treated zinc anode maintained a smooth, dense deposit morphology after cycling, demonstrating that the anode protective layer effectively inhibited corrosion and induced uniform zinc ion deposition. Symmetrical battery assembly and testing: The zinc ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery shell, a spring, a gasket, a zinc negative electrode with a protective layer, a separator, a positive electrode, and a positive electrode battery shell, using a C2032 battery shell, a positive electrode using a zinc plate with a protective layer (i.e., the positive electrode and the negative electrode are the same, both using the zinc negative electrode with a protective layer prepared as described above), a circular positive and negative electrode with a diameter of 15 mm, a circular separator using GF-D (Whatman glass fiber filter paper, GF / D, the same below), and a diameter of 19 mm; a 2M ZnSO4 aqueous solution is used as the electrolyte; finally, the battery shell is sealed and installed on the battery test channel for cyclic charge and discharge testing, with a current density of 0.5 mA / cm 2 , the charge and discharge time is maintained at 1h. Full-cell assembly and testing: The zinc-ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery case, spring, gasket, zinc negative electrode with protective layer, separator, positive electrode, and positive electrode battery case. The battery case is made of C2032, the positive electrode is MnO2, and the circular positive and negative electrodes are 15mm in diameter. The circular separator is GF-A (Whatman glass fiber filter paper, GF / A, the same below) with a diameter of 19mm. The electrolyte is an aqueous solution of 2M ZnSO4 and 0.2M MnSO4. Finally, the battery case is sealed and installed in a battery test channel for cyclic charge and discharge testing at a current density of 1C and a charge and discharge voltage of 0.8-2V. After long periods of charge and discharge, the battery still maintains a high capacity retention rate, indicating that the protective layer can prevent interfacial side reactions and improve the battery's cyclic reversibility.

[0022] Figure 1 The symmetrical battery assembled based on the negative electrode protective layer of the zinc ion battery in Example 1 is 0.5 mA / cm 2 The cycling curves at current densities of 100 nm and 100 nm are shown. The figure shows that a very small polarization voltage is maintained during the charge and discharge process and that the polarization voltage remains stable during long cycles, indicating that the negative electrode protective layer has good zinc ion conductivity and that no dendrites or byproducts are generated at the zinc negative electrode interface during the cycle.

[0023] Comparative Example 1

[0024] The zinc plates (not soaked) were directly used for battery assembly and testing (the process and conditions were the same as in Example 1).

[0025] Figure 2 The symmetrical cell based on the assembly in Comparative Example 1 was tested at 0.5 mA / cm 2 The cycling curve under the current density of . It can be seen from the figure that the polarization voltage increases rapidly after a short period of cycling, indicating that a large amount of dead zinc and by-products are formed on the surface of the new negative electrode, increasing the ion conduction resistance. Symmetrical battery assembly and testing: The zinc ion battery preparation method includes the following steps: assembling the battery in the order of negative electrode battery shell, spring, gasket, zinc negative electrode, separator, positive electrode, and positive electrode battery shell, using C2032 battery shell, bare zinc plate for both positive and negative electrodes, circular positive and negative electrodes with a diameter of 15 mm, and GF-D for circular separator with a diameter of 19 mm; using 2M ZnSO4 aqueous solution as electrolyte; finally, sealing the battery shell and installing it on the battery test channel for cyclic charge and discharge test, with a current density of 0.5 mA / cm 2 , the charge and discharge time is maintained at 1h. Full-cell assembly and testing: The zinc-ion battery preparation method includes the following steps: assembling the battery in the order of anode battery case, spring, gasket, bare zinc cathode, separator, cathode, and cathode battery case. A C2032 battery case, MnO2 positive electrode, and circular positive and negative electrodes with a diameter of 15 mm were used, and a GF-A circular separator with a diameter of 19 mm was used. An aqueous solution of 2M ZnSO4 and 0.2M MnSO4 was used as the electrolyte. Finally, the battery case was sealed and mounted on a battery test channel for cyclic charge-discharge testing at a current density of 1C and a charge-discharge voltage of 0.8-2V. The capacity retention rate rapidly decreased during the short charge-discharge period, indicating that severe interfacial side reactions reduced the battery's cyclic reversibility.

[0026] Example 2

[0027] (1) Place 0.1718 g of indium fluoride in a 250 mL flask and add 200 mL of deionized water to dissolve it. Place the flask in a sand bath and maintain the sand bath temperature at 80°C until the solute indium fluoride is completely dissolved to prepare a 5 mmol / L indium fluoride solution.

[0028] (2) After the indium fluoride solution is cooled to room temperature, it is used to soak the zinc plate for 3 minutes;

[0029] (3) The zinc plate was removed and cleaned with anhydrous ethanol. After vacuum drying at 60°C for 6 hours, a zinc negative electrode with a protective layer was obtained for battery assembly and testing. Symmetrical battery assembly and testing: The zinc ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery shell, a spring, a gasket, a zinc negative electrode with a protective layer, a separator, a positive electrode, and a positive electrode battery shell, using a C2032 battery shell, a positive electrode using a zinc plate with a protective layer (i.e., the positive electrode and the negative electrode are the same, both using the zinc negative electrode with a protective layer prepared above), a circular positive and negative electrode with a diameter of 15 mm, a circular separator using GF-D, with a diameter of 19 mm; a 2M ZnSO4 aqueous solution as the electrolyte; finally, sealing the battery shell and installing it on a battery test channel for cyclic charge and discharge testing with a current density of 0.5 mA / cm 2The charge and discharge time was maintained at 1 hour. During long-term charge and discharge, the polarization voltage remained very low and stable over long cycles, demonstrating the high stability of the zinc negative electrode. The full-cell battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery case, spring, gasket, zinc negative electrode with a protective layer, separator, positive electrode, and positive electrode battery case. The battery case used was a C2032 battery case, a MnO2 positive electrode, and circular positive and negative electrodes with a diameter of 15 mm. A GF-A circular separator with a diameter of 19 mm was used as the separator. An aqueous solution of 2M ZnSO4 and 0.2M MnSO4 was used as the electrolyte. Finally, the battery case was sealed and mounted on a battery test channel for cyclic charge and discharge testing at a current density of 1C and a charge and discharge voltage of 0.8-2V. After long periods of charge and discharge, the battery maintained a high capacity retention rate, demonstrating that the protective layer can prevent interfacial side reactions and improve the battery's cyclic reversibility.

[0030] Example 3

[0031] (1) Place 0.0203 g of copper fluoride in a 250 mL flask and add 200 mL of deionized water to dissolve it. Place the flask in a sand bath and maintain the sand bath temperature at 80°C until the solute copper fluoride is completely dissolved to prepare a 1 mmol / L copper fluoride solution.

[0032] (2) After the copper fluoride solution is cooled to room temperature, it is used to soak the zinc plate for 10 minutes;

[0033] (3) The zinc plate was removed and cleaned with anhydrous ethanol. After vacuum drying at 60°C for 6 hours, a zinc negative electrode with a protective layer was obtained for battery assembly and testing. Symmetrical battery assembly and testing: The zinc ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery shell, a spring, a gasket, a zinc negative electrode with a protective layer, a separator, a positive electrode, and a positive electrode battery shell, using a C2032 battery shell, a positive electrode using a zinc plate with a protective layer (i.e., the positive electrode and the negative electrode are the same, both using the zinc negative electrode with a protective layer prepared above), a circular positive and negative electrode with a diameter of 15 mm, a circular separator using GF-D, with a diameter of 19 mm; a 2M ZnSO4 aqueous solution as the electrolyte; finally, sealing the battery shell and installing it on a battery test channel for cyclic charge and discharge testing with a current density of 0.5 mA / cm 2 The charge and discharge time is kept at 1h. During the long-term charge and discharge process, the polarization voltage is kept very small and the polarization voltage remains stable during the long cycle process, indicating that the zinc negative electrode has high stability. Full-cell assembly and testing: The zinc-ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery case, spring, gasket, zinc negative electrode with protective layer, separator, positive electrode, and positive electrode battery case. The battery case uses a C2032 material, a MnO2 positive electrode, and circular positive and negative electrodes with a diameter of 15mm. The circular separator is GF-A with a diameter of 19mm. The electrolyte is an aqueous solution of 2M ZnSO4 and 0.2M MnSO4. Finally, the battery case is sealed and installed on a battery test channel for cyclic charge and discharge testing at a current density of 1C and a charge and discharge voltage of 0.8-2V. After long periods of charge and discharge, the battery maintains a high capacity retention rate, indicating that the protective layer can prevent interfacial side reactions and improve the battery's cyclic reversibility.

[0034] Example 4

[0035] (1) Place 0.0254 g of silver fluoride in a 250 mL flask and add 200 mL of deionized water to dissolve it. Place the flask in a sand bath and maintain the sand bath temperature at 80°C until the solute silver fluoride is completely dissolved to prepare a 1 mmol / L silver fluoride solution.

[0036] (2) After the silver fluoride solution is cooled to room temperature, it is used to soak the zinc plate for 10 minutes;

[0037] (3) The zinc plate was removed and cleaned with anhydrous ethanol. After vacuum drying at 60°C for 6 hours, a zinc negative electrode with a protective layer was obtained for battery assembly and testing. Symmetrical battery assembly and testing: The zinc ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery shell, a spring, a gasket, a zinc negative electrode with a protective layer, a separator, a positive electrode, and a positive electrode battery shell, using a C2032 battery shell, a positive electrode using a zinc plate with a protective layer (i.e., the positive electrode and the negative electrode are the same, both using the zinc negative electrode with a protective layer prepared above), a circular positive and negative electrode with a diameter of 15 mm, a circular separator using GF-D, with a diameter of 19 mm; a 2M ZnSO4 aqueous solution as the electrolyte; finally, sealing the battery shell and installing it on a battery test channel for cyclic charge and discharge testing with a current density of 0.5 mA / cm 2 The charge and discharge time is kept at 1h. During the long-term charge and discharge process, the polarization voltage is kept very small and the polarization voltage remains stable during the long cycle process, indicating that the zinc negative electrode has high stability. Full-cell assembly and testing: The zinc-ion battery preparation method includes the following steps: assembling the battery in the order of a negative electrode battery case, spring, gasket, zinc negative electrode with protective layer, separator, positive electrode, and positive electrode battery case. The battery case uses a C2032 material, a MnO2 positive electrode, and circular positive and negative electrodes with a diameter of 15mm. The circular separator is GF-A with a diameter of 19mm. The electrolyte is an aqueous solution of 2M ZnSO4 and 0.2M MnSO4. Finally, the battery case is sealed and installed on a battery test channel for cyclic charge and discharge testing at a current density of 1C and a charge and discharge voltage of 0.8-2V. After long periods of charge and discharge, the battery maintains a high capacity retention rate, indicating that the protective layer can prevent interfacial side reactions and improve the battery's cyclic reversibility. The zinc symmetrical cells assembled in Example 1 and Comparative Example 1 were heated at 0.5 mA / cm 2 The polarization stability of the zinc symmetrical battery was tested at a current density of , and the results are shown in the figure. In Example 1, the battery can stably circulate for more than 2100 hours, and in Comparative Example 1, the battery short-circuited after circulating for 300 hours. It can be seen that the stability of the negative electrode protective layer of the zinc ion battery in the aqueous zinc ion battery of the present invention is much higher than that of the negative electrode without a protective layer. This is mainly due to the close contact of the composite alloy layer formed by the reaction of zinc and metal fluoride with the zinc foil, which effectively avoids the dendrite growth on the zinc negative electrode of the zinc ion battery during charge and discharge, and realizes the rapid migration of zinc ions. The battery cycle life is higher than that of the zinc ion battery in Comparative Example 1. The above are only some of the embodiments of the invention, and do not limit the present application in any form. All raw material ratios, upper and lower limits of working conditions and interval values ​​in the preparation process of the present application can realize the present application, and the embodiments are not listed here one by one. Any person familiar with this profession, without departing from the technical solution of the present application, can make some changes or modifications to the above technical content into an equivalent embodiment of the decoration, but any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present application without departing from the content of the technical solution of the present application, still fall within the scope of the technical solution of the present application.

Claims

1. A zinc ion battery negative electrode, comprising a zinc plate, characterized in that: The zinc ion battery negative electrode is a zinc negative electrode with an alloy-fluoride hybrid layer on the surface of the zinc plate, which forms a protective layer through reaction.

2. zinc ion battery negative electrode according to claim 1, is characterized in that, It is a protective layer formed on the surface of the zinc plate by the reaction between the zinc on the zinc plate and the metal fluoride; The content of alloy-fluoride in the alloy-fluoride hybrid layer gradually decreases from the outside to the inside of the zinc plate surface, with a certain concentration gradient; The metal in the alloy is zinc and one or more of indium, silver, copper, bismuth, and magnesium; The fluoride is one or more of zinc fluoride and indium fluoride, silver fluoride, copper fluoride, bismuth fluoride, and magnesium fluoride.

3. A method for preparing a zinc ion battery negative electrode according to claim 1 or 2, characterized in that: The specific steps are as follows: (1) dissolving a metal fluoride in deionized water and / or an organic solvent and continuing the sand bath until the solute metal fluoride is completely dissolved to prepare a metal fluoride solution; The metal fluoride is one or more of indium fluoride, silver fluoride, copper fluoride, bismuth fluoride, and magnesium fluoride; (2) immersing the zinc plate in the metal fluoride solution prepared in step (1); (3) The zinc plate is removed and cleaned with anhydrous ethanol. After drying, a zinc negative electrode with an alloy-fluoride hybrid layer on the surface is obtained (which can be used for battery assembly and testing).

4. The preparation method according to claim 3, characterized in that The organic solvent in the above step (1) is one or more of methanol, ethanol, ethylene glycol, dimethyl sulfoxide, N,N-dimethylformamide, acetone, diethyl ether or ethylene glycol dimethyl ether.

5. The preparation method according to claim 3, characterized in that The concentration of the metal fluoride solution in step (1) is 0.1-10 mmol / L, more preferably the concentration of the metal fluoride solution in step (1) is 0.5-2 mmol / L.

6. The method for preparing a zinc ion battery negative electrode protective layer according to claim 3, wherein The temperature of the sand bath in the above step (1) is 50-100°C. Preferably, the temperature of the sand bath in the above step (1) is 60-80°C.

7. The preparation method according to claim 3, characterized in that The zinc plate is immersed in the step (2) for 1-10 minutes, preferably for 3-5 minutes, at a temperature of 20-40°C, preferably 25-30°C.

8. The preparation method according to claim 3, characterized in that The drying in the above step (3) is vacuum drying at 40-80° C. for 4-10 hours. Preferably, the drying in the above step (3) is vacuum drying at 50-60° C. for 6-8 hours.

9. Use of the zinc ion battery negative electrode according to claim 1 or 2 or the zinc ion battery negative electrode obtained by the preparation method according to any one of claims 3 to 7, characterized in that: It can be used as a negative electrode in aqueous zinc-ion batteries.

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