CF3 functionalized UIO-66 modified aqueous zinc ion battery diaphragm material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water-based zinc ion battery diaphragm modification, and particularly relates to a CF3 functionalized UIO-66 modified water-based zinc ion battery diaphragm material and a preparation method and application thereof.The battery diaphragm material comprises a glass fiber diaphragm, and CF3 functionalized UIO-66 is loaded on the surface of the glass fiber diaphragm; the modification effectively improves the stability of the Zn anode in the aqueous zinc ion battery. According to the preparation process, CF3 functionalized UIO-66 is loaded on the glass fiber by using a one-step hydrothermal method. The ZnZn symmetric battery assembled by using the diaphragm material can stably circulate for more than 2000 hours under the current density of 2 mA cm <-2 > and 1 mAh cm <-2 >, and meanwhile, the assembled ZnZn symmetric battery can stably circulate for more than 800 hours under the large current density of 5 mA cm <-2 > and 2 mAh cm <-2 >.

Description

Technical Field

[0001] The present invention belongs to the field of separator materials for aqueous zinc-ion batteries, and specifically relates to a CF 3 functionalized UIO-66 modified separator material for aqueous zinc-ion batteries, its preparation method and application. Background Art

[0002] Lithium-ion batteries have become the most commonly used batteries in people's daily lives because they have quite a number of advantages, such as good energy density, reaching 160 - 240 Whkg -1 ; long cycle life, about 5 - 15 years; fast charge and discharge speed, and an energy conversion rate of about 80% - 90%. Although the technology of lithium-ion batteries has been relatively mature after decades of development, due to the certain danger of lithium itself, and the high cost and difficult assembly of lithium batteries, people have to look for better electrochemical energy storage solutions.

[0003] Rechargeable aqueous zinc-ion batteries (AZIBs) have become promising candidates due to their high theoretical capacity and natural abundance of zinc. However, the inherent instability of the zinc anode brings some challenges, including the formation and growth of zinc dendrites, competitive hydrogen evolution reaction (HER), corrosion, formation of by-products, and surface passivation, all of which limit the cycle stability and hinder the practical application of AZIBs. The separator is an important component of AZIBs because, through appropriate modification, it plays an important role in improving the electrochemical performance. Glass fiber (GF) is the most commonly used separator in AZIBs because it has good compatibility with aqueous electrolytes. The main function of the GF separator is to prevent the direct contact between the cathode material and the Zn anode, thus avoiding short circuits. Although the porous structure of the GF separator is beneficial to the transport of Zn 2+ between the electrodes, the irregular distribution of pores often leads to uneven Zn flux and uneven deposition, thus resulting in the formation and growth of dendrites. Since the GF separator has limited inherent functions in AZIBs, appropriate modification can directly and effectively enhance its performance and improve the overall battery performance. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a CF 3 functionalized UIO-66 modified separator material for aqueous zinc-ion batteries, which loads CF 3 functionalized UIO-66 on the surface of glass fiber to construct a multifunctional separator material, wherein UIO-66 can induce the preferential deposition of zinc ions on the (002) crystal plane to a certain extent, and can play a role in inhibiting the generation of zinc dendrites. The introduction of the CF 3 group reduces the pore size of the hydrated Zn 2+ channel, and plays a role in promoting the hydrated Zn 2+The role of desolvation. In addition, the strong hydrophobicity of the CF 3 group can also promote the dehydration process and inhibit the HER side reaction, thereby achieving the purpose of improving the battery performance.

[0005] To achieve the above object, the present invention provides the following technical solutions: A water-based zinc-ion battery separator material modified by CF 3 functionalized UIO-66, including a glass fiber separator, on the surface of which CF 3 functionalized UIO-66 is loaded, denoted as CF 3 ) 2 -UiO-66@GF.

[0006] The present invention also provides a preparation method of the battery separator material, in which CF 3 functionalized UIO-66 is directly in-situ grown on the glass fiber separator by a one-step hydrothermal synthesis method, thereby obtaining the battery separator material.

[0007] Specifically, it includes the following steps: S1 First, zirconium chloride and 2,5-bis(trifluoromethyl)terephthalic acid are respectively weighed and added to N,N-dimethylformamide and ultrasonically dissolved. After mixing, glacial acetic acid and concentrated hydrochloric acid are added thereto, and after mixing evenly, the glass fiber separator is put into it and soaked.

[0008] S2 It is placed in an oven for reaction. After the reaction is completed, the glass fiber separator is taken out, washed, and dried to obtain the battery separator material.

[0009] Furthermore, it also includes transferring out the white turbid solution after the reaction is completed, washing, and drying to obtain white particles, which are (CF 3 ) 2 -UiO-66.

[0010] Furthermore, the molar ratio of zirconium chloride to 2,5-bis(trifluoromethyl)terephthalic acid used in the step is 1:0.5~1:1.5.

[0011] Furthermore, the concentration of zirconium chloride used is 0.028~0.033 mol L -1 .

[0012] Furthermore, the N,N-dimethylformamide used is 60~70 ml; the added glass fiber is a cut glass fiber separator with a diameter of 16~19 mm, and the number is 25~30 pieces.

[0013] Furthermore, the volume ratio of glacial acetic acid to concentrated hydrochloric acid used in the step is 1:1~2:1.

[0014] Furthermore, the reaction temperature in the step is 70 - 80 °C, and the reaction time is 20 - 24 h.

[0015] The present invention also provides an aqueous zinc-ion battery, and the separator material of the battery uses the above-mentioned modified separator material for aqueous zinc-ion batteries.

[0016] The beneficial effects of the present invention include: The present invention provides a modified separator material for aqueous zinc-ion batteries. In the modified material, CF 3 Functionalized UiO-66 can be loaded on the surface of glass fiber by a one-step hydrothermal method, which provides a new method for the design of electrode structures. The abundant CF 3 groups in this material reduce the pore size of the hydrated Zn 2+ channels, which can play a role in promoting the desolvation of hydrated Zn 2+ . At the same time, the strong hydrophobicity of the CF 3 groups can also promote the dehydration process and inhibit the HER side reaction. The high electronegativity of the CF 3 groups also regulates the electronic structure of UiO-66 and slows down its interaction strength with Zn 2+ . The CF 3 -functionalized UiO-66 on the glass fiber separator attracts Zn 2+ from the electrolyte, while ensuring a uniform ion flux, and accelerating ion transport through the optimized Zn 2+ affinity. Therefore, the high performance of such materials as battery materials is guaranteed, and ultimately the purpose of improving the cycle stability and rate performance of aqueous zinc-ion batteries is achieved.

[0017] This preparation method is simple, easy to obtain, low in price, green and environmentally friendly, and suitable for large-scale industrial production.

[0018] When the material is applied to an aqueous zinc-ion battery, it effectively solves the serious problems of zinc dendrites and hydrogen evolution on the negative electrode side of the aqueous zinc-ion battery, improves the cycle stability and rate performance of the battery, and shows excellent electrochemical performance. Using (CF 3 ) 2 -UiO-66@GF as the separator of the battery, the Zn||Zn symmetric battery assembled with this separator can stably cycle for more than 2000 h at a current density of 2 mA cm -2 and 1 mAh cm -2 . At the same time, the assembled Zn||Zn symmetric battery can stably cycle for more than 800 h at a large current density of 5 mA cm -2 and 2 mAh cm -2 . Description of the Drawings

[0019] Figure 1(CF prepared in Example 1 3 ) 2 Scanning electron microscope image of the surface of -UiO-66@GF.

[0020] Figure 2 (CF prepared in Example 1 3 ) 2 EDX elemental mapping of -UiO-66@GF.

[0021] Figure 3 Scanning electron microscope image of the surface of the zinc sheet on the negative electrode side of the Zn||Zn symmetric battery assembled in Example 1 with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator after 100 cycles.

[0022] Figure 4 Cycling performance graphs of the Zn||Zn symmetric battery assembled in Example 1 with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator at current densities of 2 mA cm -2 1 mAh cm -2 and 5 mA cm -2 2 mAh cm -2 respectively.

[0023] Figure 5 Rate performance graphs of the Zn||Zn symmetric battery assembled in Example 1 with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator at different current densities.

[0024] Figure 6 LSV curves of the Zn||Cu battery assembled in Example 1 with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator. Detailed implementation manners

[0025] The experimental scheme of the present invention will be further elaborated below in combination with specific examples, but the present invention is not limited to the following examples. The methods are all conventional methods unless otherwise specified. The raw materials or instruments can be obtained through commercial purchase unless otherwise specified.

[0026] In the following examples: Scanning Electron Microscope (SEM) Test: The instrument model of the scanning electron microscope is Nova Nano SEM 450 from FEI Company, USA. Test Sample and Preparation Method: The separator of the aqueous zinc-ion battery prepared in the example was dried and made into a sample for SEM testing.

[0027] Performance Test of Aqueous Zinc-Ion Battery: The instrument model is LAND CT2001A, Wuhan Blue Electronic Co., Ltd. Test Parameters: Charge-discharge voltage threshold 0.2 - 1.6 V, charge-discharge rate: 0.5 mA cm -2 、1.0 mA cm -2 、2.0 mA cm -2 、3.0 mA cm -2 、5.0 mA cm -2 、10.0 mA cm -2 , the capacity is constantly 1.0 mAh cm -2 , charge-discharge temperature: 30 °C. Example

[0028] First, weigh 0.466 g of zirconium chloride and 0.604 g of 2,5-bis(trifluoromethyl)terephthalic acid, and add them separately to blue-capped bottles containing 64 mL of N,N-dimethylformamide and ultrasonically dissolve. After mixing, add 8 mL of glacial acetic acid and 8 mL of concentrated hydrochloric acid and mix evenly. Then, put 30 pieces of cut glass fiber diaphragms with a diameter of 19 mm into it and soak for 10 min. Finally, place it in an oven at 80 °C and heat for 24 h. After the reaction is completed and cooled to room temperature, take out the glass fiber diaphragm and wash it 3 times with N,N-dimethylformamide and ethanol respectively, and then put it into an oven at 60 °C and dry for 12 h to finally obtain the modified glass fiber diaphragm (CF 3 ) 2 -UiO-66@GF. Transfer out the white turbid solution in the glass bottle, wash and centrifuge it 3 times with N,N-dimethylformamide and ethanol respectively, and dry it at 60 °C for 12 h. The finally obtained white particles are (CF 3 ) 2 -UiO-66.

[0029] (1) Scanning Electron Microscope Test: The test results are as Figure 1 shown, (CF 3 ) 2 -UiO-66 particles were successfully loaded on the glass fiber during the synthesis process, Figure 2 and the appearance of Zr and F in the EDX elemental mapping also fully confirmed this point. Figure 3 is for (CF 3 )2 Scanning electron microscope images of the surface of the zinc sheet on the negative electrode side of the Zn||Zn symmetric battery with -UiO-66@GF and ordinary GF as the battery separator after 100 cycles. It can be seen from the figure that with (CF 3 ) 2 -UiO-66@GF as the battery separator, the surface of the zinc sheet after cycling of the Zn||Zn symmetric battery is smoother, confirming that the CF 3 group can inhibit the formation of dendrites.

[0030] (2) Electrochemical performance test of aqueous zinc-ion battery: The Zn||Zn symmetric battery containing the separator material was subjected to charge-discharge cycling tests, with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator, and the electrolyte was 2 M ZnSO 4 solution. Figure 4 The cycling performance graphs of the Zn||Zn symmetric battery with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator at 2 mA cm -2 1 mAh cm -2 and 5 mA cm -2 2 mAh cm -2 current densities respectively. The Zn||Zn symmetric battery assembled with (CF 3 ) 2 -UiO-66@GF separator can stably cycle for more than 2000 h at a current density of 2 mA cm -2 1mAh cm -2 , and can stably cycle for more than 800 h at a large current density of 5 mA cm -2 2 mAh cm -2 . Figure 5 The rate performance graphs of the Zn||Zn symmetric battery with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator at different current densities. The Zn||Zn symmetric battery assembled with (CF 3 ) 2 -UiO-66@GF separator can still stably cycle for more than 400 h after passing through a large current.

[0031] The LSV test was carried out on the Zn|Cu battery containing the separator material, with (CF 3 ) 2 -UiO-66@GF and ordinary GF as the battery separator, and the electrolyte was 2 M Na 2 SO4 Solution. Figure 6 is (CF 3 ) 2 -UiO-66@GF and ordinary GF as the LSV curves of the Zn||Cu battery with the battery separator. The hydrogen evolution potential of the Zn||Cu battery assembled with the (CF 3 ) 2 -UiO-66@GF separator at a current density of 10 mA cm -2 is 68.7 mV, which confirms that the CF 3 group can inhibit the hydrogen evolution side reaction.

[0032] Finally, it should be noted that the above embodiments are only one of the specific implementation manners of the present invention. Although the description thereof is relatively detailed and specific, this should not be construed as a limitation on the scope of the present invention. Those skilled in the art should understand that any equivalent replacement or modification made to the present invention without departing from the technical scope of the present invention still belongs to the content of the technical solution of the present invention and is still within the protection scope of the present invention.

Claims

1. A CF3 functionalized UIO-66 modified aqueous zinc ion battery diaphragm material, characterized in that: It comprises a glass fiber diaphragm, the surface of which is loaded with CF3 functionalized UIO-66, recorded as (CF3)2-UiO-66@GF.

2. A method for preparing the battery separator material according to claim 1, characterized in that: The CF3-functionalized UIO-66 was directly grown in situ on the surface of the glass fiber separator by a one-step hydrothermal synthesis method to obtain the battery separator material.

3. The method for preparing a battery separator material according to claim 2, characterized in that: The specific steps include: S1. First, zirconium chloride and 2,5-bis(trifluoromethyl)terephthalic acid are weighed respectively, and added into N,N-dimethylformamide and dissolved by ultrasonication. After mixing, glacial acetic acid and concentrated hydrochloric acid are added thereto and mixed evenly, and then the cut glass fiber diaphragm is immersed therein; S2 is placed in an oven for reaction. After the reaction is completed, the glass fiber diaphragm is taken out, washed and dried to obtain a diaphragm material.

4. The method for preparing a battery separator material according to claim 3, characterized in that: It also includes transferring the white turbid solution after the reaction is completed, washing and drying to obtain (CF3)2-UiO-66.

5. The method for preparing a battery separator material according to claim 3, characterized in that: The molar ratio of zirconium chloride to 2,5-bis(trifluoromethyl)terephthalic acid used is 1:0.5 to 1:1.

5.

6. The method for preparing a battery separator material according to claim 3, characterized in that: The concentration of zirconium chloride used was 0.028~0.033 mol L -1 .

7. The method for preparing a battery separator material according to claim 3 or 6, characterized in that: The amount of N,N-dimethylformamide used is 60-70 ml; the amount of glass fiber added is 25-30 pieces of cut glass fiber diaphragm with a diameter of 16-19 mm.

8. The method for preparing a battery separator material according to claim 3, characterized in that: The volume ratio of glacial acetic acid and concentrated hydrochloric acid used is 1:1~2:

1.

9. The method for preparing a battery separator material according to claim 3, characterized in that: The reaction temperature is 70~80℃ and the reaction time is 20~24h.

10. An aqueous zinc ion battery, characterized in that: The battery separator material is the battery separator material according to claim 1.

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