Preparation method and application of aqueous zinc ion battery functionalized separator

Abstract

The present application relates to the technical field of battery materials, in particular to a preparation method and application of a functionalized separator for aqueous zinc ion battery. A mixed solution of a complex of a polymer molecular chain and a zinc-containing compound is prepared, and the glass fiber membrane is suspended in the mixed solution and left to stand, so that the separator is modified. Then, the modified functionalized separator is dried to obtain the modified functionalized separator. The present application prepares a separator material with uniform pore size and negative electric property, and introduces a long-chain molecule with negative electric property, so that the zinc ions are transported along the long chain, and the uniform deposition of zinc ions in the battery cycle is guided, thereby effectively inhibiting the growth of zinc negative electrode dendrites to pierce the separator, and finally obtaining an aqueous zinc ion battery with excellent cycle performance. The preparation method is very simple, and the cycle stability can be improved to more than 14 times of the original under the same test conditions, which shows a broad application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery materials, in particular to a preparation method and application of a functionalized separator for aqueous zinc-ion batteries. BACKGROUND

[0002] With the rapid rise in demand for energy, aqueous zinc-ion batteries stand out among many energy storage batteries. Aqueous zinc-ion batteries have extremely high ionic conductivity, and aqueous electrolytes have higher safety and environmental friendliness compared with organic electrolytes that dominate lithium batteries. In addition, high-capacity zinc metal anodes can partially compensate for the loss of energy density caused by voltage limitations, and zinc metal is abundant and inexpensive. Therefore, aqueous zinc-ion batteries have important significance in the future development of energy storage.

[0003] In practical application, aqueous zinc-ion batteries still face many key problems. First, the uncontrolled two-dimensional diffusion behavior of zinc ions and the uneven distribution of electric field lead to the growth of zinc anode dendrites piercing the separator, causing battery short circuits, and the dendrites that fall off the negative electrode also reduce the coulombic effect. Second, the hydrogen evolution reaction (HER) caused by the aqueous electrolyte and the corrosion passivation of the zinc anode are important problems affecting the service life of zinc batteries.

[0004] The separator, as one of the important components of the battery, blocks the direct contact of the positive and negative electrodes and regulates the migration of zinc ions. Glass fiber is commonly used as a battery separator, but glass fiber membranes have poor mechanical properties, low ionic conductivity, and their zincophilic nature induces Zn 2+ growth on the separator, which easily pierces the separator, leading to battery short circuits. Functional modification of the separator is a practical solution to improve its performance. SUMMARY

[0005] The present application aims to solve the problem of zinc anode dendrite growth piercing the separator, causing battery short circuits, and provides a preparation method and application of a functionalized separator for aqueous zinc-ion batteries. The present application prepares a separator material with uniform pore size and negative charge, and introduces a long-chain molecule with negative charge, which allows zinc ions to transport along the long chain and guide the uniform deposition of zinc ions during battery cycling, thereby effectively inhibiting the growth of zinc anode dendrites piercing the separator, and ultimately obtaining aqueous zinc-ion batteries with excellent cycling performance.

[0006] The technical scheme adopted is as follows:

[0007] A preparation method of a functionalized separator for aqueous zinc-ion batteries, comprising the following steps:

[0008] (1) adding a polymer molecular chain to an aqueous solution and ultrasonically mixing until uniform;

[0009] (2) dispersing a zinc-containing compound in the solution and ultrasonically mixing until uniform;

[0010] (3) mixing the solutions prepared in step (1) and step (2) and mixing uniformly by ultrasonic;

[0011] (4) completely wetting the glass fiber membrane in the mixed solution of step (3) and suspending it in the mixed solution and standing;

[0012] (5) rinsing the prepared membrane and drying.

[0013] Preferably, in the step (1), the polymer molecules are sodium poly (p-styrenesulfonate).

[0014] Preferably, the mass concentration of the sodium poly (p-styrenesulfonate) used is 0-4%.

[0015] Preferably, in the step (2), the zinc-containing compound is zinc chloride, zinc sulfate, zinc acetylacetonate, zinc triflate or zinc bis (trifluoromethylsulfonyl) imide.

[0016] Preferably, the concentration of the zinc-containing compound mixed with the solution is 0-5%.

[0017] Preferably, in the step (2), the solution is a mixture of one or more of water, dichloromethane, n-hexane and hexadecane.

[0018] Preferably, in the step (4), the glass fiber membrane is completely wetted at room temperature; and standing at room temperature for 12-48h.

[0019] Preferably, in the step (5), the prepared membrane is rinsed with deionized water for 2-5 times.

[0020] Preferably, after rinsing, the membrane is dried in a drying oven at 60℃ for 12h.

[0021] The application of the membrane prepared by the preparation method of the application in the aqueous zinc ion battery, the functional membrane of the aqueous zinc ion battery guides the uniform deposition of zinc ions in the battery cycle process, thereby effectively inhibiting the growth of zinc negative electrode dendrites to pierce the membrane, and finally obtaining an aqueous zinc ion battery with excellent cycle performance.

[0022] The principle of the application is to construct a functional membrane by in-situ growth of the complex of sodium poly (p-styrenesulfonate) and zinc-containing compound on the surface of the glass fiber of the glass fiber membrane. Under an external electric field, because a large number of negatively charged sulfonic acid groups are uniformly attached to the surface of the membrane, zinc ions are first guided to uniformly disperse on the surface of the membrane, and there are also negatively charged sulfonic acid groups in the pore diameter of the membrane. Because there is electrostatic attraction between the sulfonic acid groups and the zinc ions, the zinc ions can quickly move in the pore diameter of the membrane, thereby successfully constructing a zinc ion rapid migration channel, so that the Zn 2+The uniform and rapid deposition of Zn onto the electrode surface effectively avoids the tip effect and suppresses the formation of Zn dendrites. Simultaneously, the in-situ grown membrane exhibits a more uniform pore size distribution and further reduced pore size, which is also beneficial for Zn growth. 2+ Uniform deposition.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention involves preparing a mixed solution of polymer molecular chains and a zinc-containing compound complex. By suspending a glass fiber membrane in this mixed solution and allowing it to stand, the membrane is modified. Subsequently, the membrane is dried to obtain a modified functionalized membrane. The preparation process is very simple, and the cycle stability can be improved to more than 14 times the original under the same testing conditions, demonstrating broad application prospects. Attached Figure Description

[0025] Figure 1 This is a surface electron microscope (SEM) image of the glass fiber membrane of the comparative example of the present invention;

[0026] Figure 2 This is a surface electron microscope (SEM) image of the functionalized glass fiber membrane of Embodiment 7 of the present invention;

[0027] Figure 3 X-ray photoelectron spectroscopy (XPS) spectra of the glass fiber membrane of the comparative example of the present invention and the functionalized glass fiber membrane prepared in Example 7.

[0028] Figure 4 This is a high-resolution XPS peak diagram of zinc in a glass fiber membrane of the comparative example of the present invention;

[0029] Figure 5 This is a high-resolution XPS peak diagram of zinc in the functionalized glass fiber membrane of Embodiment 7 of the present invention. Detailed Implementation

[0030] The accompanying drawings are for illustrative purposes only; the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the technical solutions of the present invention are not limited to the embodiments described below.

[0031] In the following examples, the cycling stability was tested at 25°C.

[0032] Comparison Example

[0033] This comparative example provides a method for processing a glass fiber diaphragm, comprising the following steps:

[0034] (1) Add deionized water to a beaker and sonicate.

[0035] (2) At room temperature, the glass fiber diaphragm is completely wetted in the aqueous solution and suspended in the aqueous solution. It is then left to stand at room temperature for 24 hours.

[0036] (3) Rinse the diaphragm three times with deionized water.

[0037] (4) Dry the obtained diaphragm at 60°C for 12 hours.

[0038] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 130 hours within its area capacity.

[0039] Example 1

[0040] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following:

[0041] (1) Add sodium poly(p-styrene sulfonate) with a mass concentration of 4% to the aqueous solution and mix thoroughly by ultrasonication.

[0042] (2) Dissolve zinc chloride with a mass concentration of 0% in an aqueous solution and mix it evenly by ultrasonication.

[0043] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0044] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 12 hours.

[0045] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0046] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 190 hours within its area capacity.

[0047] Example 2

[0048] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following steps:

[0049] (1) Add sodium poly(p-styrene sulfonate) with a mass concentration of 4% to the aqueous solution and mix thoroughly by ultrasonication.

[0050] (2) Dissolve zinc chloride with a mass concentration of 2.5% in an aqueous solution and mix it evenly by ultrasonication.

[0051] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0052] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 12 hours.

[0053] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0054] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 500 hours within its area capacity.

[0055] Example 3

[0056] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following:

[0057] (1) Add sodium poly(p-styrene sulfonate) with a mass concentration of 4% to the aqueous solution and mix thoroughly by ultrasonication.

[0058] (2) Dissolve 5% zinc chloride in an aqueous solution and mix it evenly by ultrasonication.

[0059] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0060] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 12 hours.

[0061] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0062] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 450 hours within its area capacity.

[0063] Example 4

[0064] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following:

[0065] (1) Add sodium poly(p-styrene sulfonate) with a mass concentration of 0% to the aqueous solution and mix thoroughly by ultrasonication.

[0066] (2) Dissolve zinc chloride with a mass concentration of 2.5% in an aqueous solution and mix it evenly by ultrasonication.

[0067] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0068] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 12 hours.

[0069] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0070] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 200 hours within its area capacity.

[0071] Example 5

[0072] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following steps:

[0073] (1) Add 2% sodium poly(p-styrene sulfonate) to the aqueous solution and mix thoroughly by ultrasonication.

[0074] (2) Dissolve zinc chloride with a mass concentration of 2.5% in an aqueous solution and mix it evenly by ultrasonication.

[0075] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0076] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 12 hours.

[0077] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0078] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 1000 hours within its area capacity.

[0079] Example 6

[0080] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following steps:

[0081] (1) Add 2% sodium poly(p-styrene sulfonate) to the aqueous solution and mix thoroughly by ultrasonication.

[0082] (2) Dissolve zinc chloride with a mass concentration of 2.5% in an aqueous solution and mix it evenly by ultrasonication.

[0083] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0084] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 48 hours.

[0085] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0086] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 1200 hours within its area capacity.

[0087] Example 7

[0088] A method for preparing a functionalized separator for an aqueous zinc-ion battery includes the following steps:

[0089] (1) Add 2% sodium poly(p-styrene sulfonate) to the aqueous solution and mix thoroughly by ultrasonication.

[0090] (2) Dissolve zinc chloride with a mass concentration of 2.5% in an aqueous solution and mix it evenly by ultrasonication.

[0091] (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous.

[0092] (4) At room temperature, the glass fiber diaphragm is completely wetted in the mixed solution and suspended in the solution. It is then left to stand at room temperature for 24 hours.

[0093] (5) Rinse the diaphragm three times with deionized water and dry the resulting diaphragm at 60°C for 12 hours.

[0094] Coin cells were assembled using glass fiber separators treated by the above method, and battery cycle stability tests were conducted. The results showed a stability at 0.1 mA cm⁻¹. -2 Current density, 0.1 mAh cm⁻¹ -2 It can maintain a cycle of up to 1800 hours within its area capacity.

[0095] The functionalized modified membrane prepared by the above method was subjected to a temperature of 0.1 mA cm⁻¹ -2Current density, 0.1 mAh cm⁻¹ -2 Cyclic stability tests were conducted at the area capacity, and the test results of battery separators prepared under different conditions are shown in Table 1.

[0096] Table 1. Battery cycle stability performance (0.1 mA cm⁻¹) of Examples 1-7 and the control example. -2 0.1mAh cm -2 Test results

[0097]

[0098]

[0099] From the test results of Examples 1-7 and the control examples in Table 1, it can be seen that when the mass concentration of sodium poly(p-styrene sulfonate) remains constant, the cycling stability first increases and then decreases with the increase of zinc chloride concentration; when the mass concentration of zinc chloride remains constant, the cycling stability first increases and then decreases with the increase of sodium poly(p-styrene sulfonate) concentration. This is because if the concentration is too low, the complex distribution is uneven; if the concentration is too high, too much complex will clog the pores, affecting the Zn concentration. 2+ The transport of Zn. While keeping the additive concentration constant, the cycle stability initially increases and then decreases with increasing settling time. This is because if the settling time is too short, the complex distribution is uneven; if the settling time is too long, excessive complex deposition clogs the pores, affecting Zn transport. 2+ The transmission rate was [data missing]. The maximum duration of cycle stability was 1800 hours, which is 14 times that of the control example.

[0100] We performed electron microscopy on the functionalized modified membranes prepared in the control example and Example 7, such as... Figure 1 and Figure 2 As shown, Figure 1 Electron micrographs of the membrane surface of the control membrane (GF) at different magnifications. Figure 2 Electron micrographs of the surface of the functionalized separator (GF / PSS-ZnCl2) for aqueous zinc-ion batteries prepared in Example 7 at different magnifications, for comparison. Figure 1 and Figure 2 It can be seen that the surface pore size of the functionalized modified separator for aqueous zinc-ion batteries prepared by in-situ modification is reduced and more uniform.

[0101] Figure 3 The image shown is an X-ray photoelectron spectroscopy (XPS) spectrum of the film surface in the control example and Example 7. Figure 4 , 5 The images shown are high-resolution XPS peak diagrams of zinc on the surfaces of the control diaphragm and the functionalized glass fiber membrane obtained in Example 7, respectively. Figure 4 and Figure 5As can be seen in Example 7, the peak intensity of zinc element increased significantly after the glass fiber membrane was modified, proving that the complex was successfully grown in situ on the membrane surface.

[0102] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a functionalized separator for an aqueous zinc-ion battery, characterized in that, Includes the following steps: (1) Add the polymer molecular chain to the aqueous solution and mix thoroughly by ultrasonication; (2) Disperse the zinc-containing compound in the solution and mix it evenly by ultrasonication; (3) Mix the solutions prepared in step (1) and step (2) and sonicate them until homogeneous; (4) Completely wet the glass fiber diaphragm in the mixed solution of step (3) and let it stand in the mixed solution; (5) Rinse the prepared diaphragm and then dry it. The polymer molecule is sodium poly(p-styrene sulfonate); the zinc-containing compounds are zinc chloride, zinc sulfate, zinc acetylacetone, zinc trifluoromethanesulfonate, and zinc bis(trifluoromethanesulfonyl)imide.

2. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 1, characterized in that, The mass concentration of sodium poly(p-styrene sulfonate) used is 2-4%.

3. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 1, characterized in that, The mass concentration of the zinc-containing compound used in the solution was 2.5% to 5%.

4. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 1, characterized in that, In step (2), the solution is one or more of water, dichloromethane, n-hexane, and hexadecane.

5. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 1, characterized in that, In step (4), the glass fiber diaphragm is completely wetted at room temperature and left to stand at room temperature for 12 to 48 hours.

6. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 1, characterized in that, In step (5), the prepared diaphragm is rinsed with deionized water 2 to 5 times.

7. The method for preparing a functionalized separator for an aqueous zinc-ion battery according to claim 6, characterized in that, After rinsing, dry in a drying oven at 60℃ for 12 hours.

8. The application of the separator prepared according to claims 1 to 7 in aqueous zinc-ion batteries.

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