Preparation method of glass fiber diaphragm modified with bismuth-based metal-organic framework material, its product and application

Abstract

The present invention discloses a method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material, comprising: (1) using bismuth nitrate pentahydrate and trimesic acid as raw materials, and synthesizing a bismuth-based metal organic framework material by solvent thermal reaction; (2) adding the bismuth-based metal organic framework material prepared in step (1) and polyvinylidene fluoride to an N-methylpyrrolidone solution for mixing; (3) modifying the mixed solution obtained in step (2) onto a glass fiber diaphragm by a suction filtration method, and obtaining a glass fiber diaphragm modified with a bismuth-based metal organic framework material after drying. The present invention also discloses a glass fiber diaphragm modified with a bismuth-based metal organic framework material obtained by the above-mentioned preparation method and its application in a zinc ion battery. The glass fiber diaphragm modified with a bismuth-based metal organic framework material provided by the present invention can improve its electrochemical performance when applied to a zinc ion battery, thereby solving the problem of poor cycle performance of ordinary glass fiber diaphragms applied to aqueous batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of aqueous zinc ion batteries, and in particular to a preparation method of a glass fiber diaphragm modified with a bismuth-based metal organic framework material, and a product and application thereof. Background Art

[0002] With the widespread use of smart electronic devices, the development of safe, efficient and long-lasting energy storage devices has become urgent. Currently, lithium-ion batteries lead the commercial market with their high energy density and long cycle life. However, the growing demand for low cost and safety has prompted people to seek alternative battery systems for large-scale application. Rechargeable aqueous zinc-ion batteries are considered to be one of the most promising candidates because they have abundant zinc sources and mild aqueous electrolytes. Compared with other metal anodes, zinc has a low redox potential (compared to the standard hydrogen electrode at -0.76 V) and a high theoretical capacity (820 mAh g -1 ,5851mAh cm -3 ), which can provide high energy density for batteries.

[0003] The main factors limiting the development of aqueous zinc-ion batteries are dendrite growth and a series of side reactions induced by water molecules. As an indispensable part of aqueous zinc-ion batteries, the diaphragm plays a vital role in ion transport. However, commercial glass fiber diaphragms have irregular pores and cannot fully regulate ion transport, resulting in dendrite growth, which eventually pierces the diaphragm and causes battery short circuit. In order to solve these problems faced by the zinc negative electrode, an effective strategy is to modify the diaphragm to achieve its long cycle life. "Nano-Micro Letters" (2022, Vol. 14, p. 218) publicly reported a diaphragm (UiO-66-GF) modified by a zirconium-based metal-organic framework. The modified diaphragm exhibits a preferential orientation of the (002) crystal plane and enhances the carrier transport capacity, which is conducive to corrosion resistance and dendrite-free zinc deposition. Therefore, at 2 mAcm -2 and 1mAhcm -2 Under the conditions of 1600 hours of cycle life of zinc symmetric battery, a study published in Journal of Science: Advanced Materials and Devices (2022, Vol. 7, p. 100467) showed that the modified membrane enhanced the zinc ion transport by introducing a zirconium-based metal organic framework (MOF-808) on a commercial glass fiber separator, and the cycle life of the zinc symmetric battery exceeded 1600 hours at 0.1 mA cm -2 and 0.1 mAh cm -2 Under the conditions of , the zinc symmetrical battery can operate stably for 350 hours.

[0004] Although metal-organic frameworks (MOFs) have been widely used, the preparation of high-performance membranes modified with these materials remains a challenge. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a glass fiber membrane modified with a bismuth-based metal-organic framework material. The glass fiber membrane modified with a bismuth-based metal-organic framework material obtained by the simple preparation method can improve the electrochemical performance of zinc ion batteries when used, thereby solving the problem of poor cycle performance of ordinary glass fiber membranes when used in aqueous batteries.

[0006] The present invention provides the following technical solutions:

[0007] A method for preparing a glass fiber diaphragm modified with a bismuth-based metal-organic framework material, the method comprising the following steps:

[0008] (1) Bismuth-based metal-organic frameworks were synthesized by solvothermal reaction using bismuth nitrate pentahydrate and trimesic acid as raw materials;

[0009] (2) adding the bismuth-based metal organic framework material prepared in step (1) and polyvinylidene fluoride to a solvent to obtain a mixed solution;

[0010] (3) The mixed solution obtained in step (2) is modified onto a glass fiber membrane by suction filtration, and after drying, a glass fiber membrane modified with a bismuth-based metal organic framework material is obtained.

[0011] Preferably, in step (1), the feed amounts of bismuth nitrate pentahydrate and trimesic acid are 50-250 mg and 500-900 mg, respectively. One bismuth atom coordinates with three trimesic acids, and a sufficient amount of trimesic acid is required to ensure the formation of the metal-organic framework material.

[0012] Preferably, in step (1), the solvothermal reaction temperature is 100-130° C. and the reaction time is 20-30 hours. Under different temperatures and times, the properties of the solvent (density, viscosity, etc.) affect each other and vary greatly, and the solubility, dispersion, and reactivity of the reactants also vary. The selected conditions can ensure the normal synthesis of the bismuth-based metal-organic framework material.

[0013] Further preferably, in step (1), 50-250 mg of bismuth nitrate pentahydrate and 500-900 mg of trimesic acid are added to 40-100 mL of anhydrous methanol solution, ultrasonicated for 5-30 minutes to dissolve the solid, then solvent-thermally reacted at 100-130° C. for 20-30 hours, and finally centrifugally dried to obtain a bismuth-based metal-organic framework material powder.

[0014] Preferably, in step (2), the solvent is N-methylpyrrolidone.

[0015] Preferably, in step (2), the total concentration of bismuth-based metal organic framework material and polyvinylidene fluoride in the mixed solution is 1-10 mg·mL -1 PVDF is sticky and highly hydrophobic; using a small amount of PVDF as a binder prevents the bismuth-based metal-organic framework from falling off. Excessive PVDF increases the material's hydrophobicity, hindering zinc ion transport and negatively impacting battery performance.

[0016] Preferably, in step (3), the glass fiber membrane is cut into small discs with a diameter of 20 mm, the bismuth-based metal-organic framework material is loaded onto the membrane by filtration, and dried in a vacuum oven at 60-80°C for 10-20 hours to obtain a glass fiber membrane modified with a bismuth-based metal-organic framework material.

[0017] Preferably, in step (3), the loading amount of the bismuth-based metal organic framework material on the glass fiber membrane modified with the bismuth-based metal organic framework material is 1-3 mg·cm -2 If the loading amount is too low, the separator cannot be modified well, the zinc ion flux cannot be uniform, and dendrite growth still occurs at the zinc negative electrode; if the loading amount is too high, the bismuth-based metal-organic framework material is easy to fall off, the zinc ion flux cannot be stably regulated, and the dendrite growth cannot be inhibited.

[0018] Further preferably, the feeding amounts of bismuth nitrate pentahydrate and trimesic acid are 150 mg and 750 mg respectively; the temperature of the solvent thermal reaction is 120° C. and the time is 24 h; the total concentration of bismuth-based metal organic framework material and polyvinylidene fluoride in the mixed solution is 3.3-6.7 mg·mL -1 The mass ratio of the bismuth-based metal organic framework material to polyvinylidene fluoride is 9:1; the loading amount of the bismuth-based metal organic framework material on the glass fiber diaphragm modified by the bismuth-based metal organic framework material is 2.2-2.6 mg cm -2 The glass fiber separator modified with the bismuth-based metal-organic framework prepared under the above process conditions was used as the separator of zinc-ion batteries, and the assembled battery device showed better electrochemical performance.

[0019] The invention also discloses a glass fiber diaphragm modified with a bismuth-based metal organic framework material obtained by the preparation method.

[0020] The present invention also discloses an application of a glass fiber diaphragm modified with the bismuth-based metal organic framework material in a zinc ion battery.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] (1) The present invention adopts a simple filtration method to modify the bismuth-based metal organic framework material onto an ordinary glass fiber separator, which effectively improves the interface between the separator and the electrode, enhances the zinc ion transmission kinetics, and greatly improves the battery life.

[0023] (2) The preparation method of the glass fiber diaphragm modified with the bismuth-based metal organic framework material provided by the present invention has low cost, small equipment investment, simple operation, and is suitable for large-scale production.

[0024] (3) The glass fiber diaphragm modified with the bismuth-based metal-organic framework material prepared by the present invention is used as a diaphragm for zinc ion batteries. The assembled battery device exhibits good electrochemical performance and also provides a new idea for the design of aqueous battery diaphragms. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the XRD pattern of the bismuth-based metal-organic framework material measured by the D8 X-ray diffractometer of Bruker Corporation in the United States, wherein the abscissa X is the diffraction angle (2θ) and the ordinate Y is the relative diffraction intensity.

[0026] Figure 2 The nitrogen isothermal adsorption-desorption curves and corresponding pore size distributions of bismuth-based metal-organic framework materials were measured.

[0027] Figure 3 The surface morphology of the glass fiber diaphragm modified with the bismuth-based metal organic framework material prepared in Example 1, Comparative Example 1 and Comparative Example 2 was observed using a Hitachi S-4800 field emission scanning electron microscope (FE-SEM).

[0028] Figure 4 The zinc symmetric battery of Example 1 is 1 mA·cm -2 Cycle life of constant current charge and discharge for 1 h at current density.

[0029] Figure 5 is the zinc ion migration coefficient of the modified diaphragm of Example 1.

[0030] Figure 6 It is the ionic conductivity of ordinary diaphragm and modified diaphragm.

[0031] Figure 7 This is the surface morphology of the zinc electrode after cycling using ordinary and modified diaphragms, observed using a Hitachi S-4800 field emission scanning electron microscope (FE-SEM).

[0032] Figure 8 The zinc symmetric battery of Example 2 is 1 mA·cm -2 Cycle life of constant current charge and discharge for 1 h at current density.

[0033] Figure 9The zinc symmetric battery of Example 1 is 1 mA·cm -2 Cycle life of constant current charge and discharge for 1 h at current density.

[0034] Figure 10 This is the surface morphology of the zinc electrode after cycling using a small amount of bismuth-based metal-organic framework to modify the diaphragm, observed by Hitachi S-4800 field emission scanning electron microscope (FE-SEM).

[0035] Figure 11 The zinc symmetric battery of Example 2 is 1 mA·cm -2 Cycle life of constant current charge and discharge for 1 h at current density.

[0036] Figure 12 This is the surface morphology of the zinc electrode after cycling using an excess bismuth-based metal-organic framework to modify the diaphragm, observed using a Hitachi S-4800 field emission scanning electron microscope (FE-SEM).

[0037] Figure 13 The zinc symmetric battery of Example 3 is at 1 mA·cm -2 Cycle life of constant current charge and discharge for 1 h at current density.

[0038] Figure 14 This is the cyclic voltammetry test curve of the button battery assembled in the test application example of Shanghai Chenhua Company's CHI 660E electrochemical workstation.

[0039] Figure 15 This is the electrochemical cycle performance of the button battery assembled in the test application example of Wuhan Blue Electric Company's CT3001A test system. DETAILED DESCRIPTION

[0040] The above contents of the present invention are further described in detail below through examples, comparative examples and drawings, but this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention.

[0041] Example 1

[0042] Preparation and characterization of bismuth-based metal-organic framework modified glass fiber membranes

[0043] Step 1, Preparation and characterization of bismuth-based metal-organic framework materials

[0044] 150 mg of bismuth nitrate pentahydrate and 750 mg of trimesic acid were weighed and put into 60 mL of anhydrous methanol solution. The solid was dissolved by ultrasonication for 20 minutes, and then hydrothermally reacted at 120°C for 24 hours. Finally, the bismuth-based metal-organic framework material powder was obtained by centrifugal drying. Figure 1As shown in Figure 2, according to XRD, the synthesized sample corresponds to the phase of bismuth-based metal organic framework material, indicating that the synthesis is successful. The nitrogen isothermal adsorption and desorption curve test is as follows: Figure 2 As shown in the figure, the bismuth-based metal organic framework material has micropores centered at 0.8 nm. This porous characteristic and large specific surface area (634.28 m 2 g -1 ) provides appropriate transport pathways to guide uniform ion flux, which is beneficial for dendrite-free Zn deposition on the Zn electrode surface.

[0045] Step 2: Preparation of Bismuth-based Metal-Organic Framework Modified Glass Fiber Diaphragm

[0046] 18 mg of bismuth-based metal-organic framework powder and 2 mg of polyvinylidene fluoride were dissolved in 3 mL of N-methylpyrrolidone solution. The solids were evenly dispersed by ultrasound. A commercial glass fiber diaphragm was cut into small discs with a diameter of 20 mm. 1.5 mL of the mixed solution was filtered and then dried in a vacuum oven at 60 °C for 12 h to obtain a modified diaphragm (with a loading of 2.55 mg cm-1 of bismuth-based metal-organic framework material). -2 ).

[0047] Step 3: Characterization of surface morphology of diaphragms with different modification amounts and performance of assembled Zn-Zn symmetric batteries

[0048] The membranes prepared in Comparative Example 1, Comparative Example 2 and Example 1 were subjected to SEM testing, and the results were as follows: Figure 3 As shown, the modification amount is 0.64 mg cm -2 The membrane is partially filled with bismuth-based metal-organic framework materials. The modification amount is 3.50 mg cm -2 When the bismuth-based metal organic framework material layer filled on the diaphragm is oxidized, cracks appear. The modification amount is 2.55 mg cm -2 When the bismuth-based metal-organic framework material is uniformly modified onto the glass fiber membrane.

[0049] Assemble symmetrical batteries and perform constant current charge and discharge tests (cycle life). When the modification amount is 8 mg, the results are as follows: Figure 4 As shown in Figure 2, the cycle life reaches 4400h, indicating that the use of a suitable amount of bismuth-based metal organic framework modified separator can greatly improve the battery life, and the ion migration number of the symmetric battery is as follows: Figure 5 As shown, t Zn 2+ can reach 0.809. In addition, the ionic conductivity is tested as Figure 6 As shown in Figure 2, the ionic conductivity of the battery using the bismuth-based metal-organic framework modified separator reached 9.83 mS cm -1 (Ordinary diaphragm is 6.88mS cm -1). High ionic conductivity reduces the internal resistance of the battery and gives the battery better rate performance.

[0050] Step 4, characterization of zinc electrode after cycling

[0051] After the cycle test of the symmetrical zinc battery assembled with ordinary glass fiber separator and bismuth-based metal organic framework modified separator, the zinc electrode was characterized by SEM. Figure 7 As shown, when using ordinary membranes, a large number of dendrites appear on the zinc surface, while the introduction of bismuth-based metal-organic frameworks results in dense and uniform zinc deposition on the zinc surface without dendrite formation.

[0052] Example 2

[0053] Step 1, Preparation and characterization of bismuth-based metal-organic framework materials

[0054] Referring to Example 1, a bismuth-based metal-organic framework was synthesized.

[0055] Step 2: Preparation of Bismuth-based Metal-Organic Framework Modified Glass Fiber Diaphragm

[0056] 18 mg of bismuth-based metal-organic framework powder and 2 mg of polyvinylidene fluoride were dissolved in 6 mL of N-methylpyrrolidone solution. Ultrasonication was used to evenly disperse the solids. A commercial glass fiber diaphragm was cut into small discs with a diameter of 20 mm. 3 mL of the mixed solution was filtered and then dried in a vacuum oven at 60 °C for 12 h to obtain a modified diaphragm (with a loading of 2.23 mg cm-1 of bismuth-based metal-organic framework material). -2 ).

[0057] Step 3: Assemble the Zn-Zn symmetric battery and characterize its performance

[0058] Symmetrical battery constant current charge and discharge test (cycle life) results are as follows Figure 8 As shown, the cycle life reaches 900h.

[0059] Comparative Example 1

[0060] Step 1, Preparation and characterization of bismuth-based metal-organic framework materials

[0061] Referring to Example 1, a bismuth-based metal-organic framework was synthesized.

[0062] Step 2: Preparation of Bismuth-based Metal-Organic Framework Modified Glass Fiber Diaphragm

[0063] 18 mg of bismuth-based metal-organic framework powder and 2 mg of polyvinylidene fluoride were dissolved in 6 mL of N-methylpyrrolidone solution. Ultrasonication was used to evenly disperse the solids. A commercial glass fiber diaphragm was cut into small discs with a diameter of 20 mm. 1 mL of the mixed solution was filtered and then dried in a vacuum oven at 60 °C for 12 h to obtain a modified diaphragm (with a loading of 0.64 mg cm-1 of bismuth-based metal-organic framework material). -2 ).

[0064] Step 3: Assemble the Zn-Zn symmetric battery and characterize its performance

[0065] Symmetrical cells were assembled and subjected to constant current charge and discharge tests (cycle life) with a modification amount of 0.64 mg cm -2 When the result is Figure 9 As shown, the cycle life is only 220h. The ionic conductivity is tested as follows Figure 6 As shown, it is only 6.95mS cm -1 .

[0066] Step 4, characterization of zinc electrode after cycling

[0067] After the cycle test of the symmetrical zinc battery assembled with a small amount of bismuth-based metal-organic framework modified separator, the zinc electrode was characterized by SEM. Figure 10 As shown, a large number of dendrites appeared on the zinc surface of the separator modified with a small amount of non-uniform bismuth-based metal-organic framework, indicating that the separator modified with a small amount of bismuth-based metal-organic framework cannot induce uniform zinc deposition.

[0068] Comparative Example 2

[0069] Step 1, Preparation and characterization of bismuth-based metal-organic framework materials

[0070] Referring to Example 1, a bismuth-based metal-organic framework was synthesized.

[0071] Step 2: Preparation of Bismuth-based Metal-Organic Framework Modified Glass Fiber Diaphragm

[0072] 18 mg of bismuth-based metal-organic framework powder and 2 mg of polyvinylidene fluoride were dissolved in 3 mL of N-methylpyrrolidone solution. Ultrasonication was used to evenly disperse the solids. A commercial glass fiber diaphragm was cut into small discs with a diameter of 20 mm. 2 mL of the mixed solution was filtered and then dried in a vacuum oven at 60 °C for 12 h to obtain a modified diaphragm (with a loading of 3.50 mg·cm of bismuth-based metal-organic framework material). -2 ).

[0073] Step 3: Assemble the Zn-Zn symmetric battery and characterize its performance

[0074] Symmetrical cells were assembled and subjected to constant current charge and discharge tests (cycle life) with a modification amount of 3.50 mg cm -2When the result is Figure 11 As shown, the cycle life is only 210h. The ionic conductivity is tested as follows Figure 6 As shown, it is only 6.89mS cm -1 .

[0075] Step 4, characterization of zinc electrode after cycling

[0076] After the cycle test of the symmetrical zinc battery assembled with the separator modified by excess bismuth-based metal-organic framework, the zinc electrode was characterized by SEM. Figure 12 As shown, a large number of dendrites appeared on the zinc surface of the separator modified with excess bismuth-based metal-organic framework, indicating that the separator modified with excess bismuth-based metal-organic framework cannot induce uniform zinc deposition.

[0077] Comparative Example 3

[0078] Ordinary commercial glass fiber was used as a separator to assemble a 2025 type button battery. The battery was charged and discharged at a constant current. The cycle life was only 70h. Figure 13 shown.

[0079] Application Examples

[0080] A full cell was assembled using manganese dioxide as the positive electrode material, zinc sheet as the negative electrode, and 2M ZnSO4+0.2M MnSO4 as the electrolyte. -1 The cyclic voltammetry curve test was carried out at a scan rate of Figure 14 As shown. After using the bismuth-based metal organic framework material modified membrane, the battery has a higher redox current density and a larger electroactive area. -1 The maximum discharge capacity reaches 221.8 mAh g -1 Then the electrochemical cycle performance test was carried out, such as Figure 15 As shown. In 1Ag -1 After 2400 cycles, the specific capacity is 141.7 mAh g -1 , with a high capacity retention rate of 91%.

[0081] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a glass fiber diaphragm modified with a bismuth-based metal-organic framework material, characterized in that: The preparation method comprises the following steps: (1) Bismuth-based metal-organic frameworks were synthesized by solvothermal reaction using bismuth nitrate pentahydrate and trimesic acid as raw materials; (2) adding the bismuth-based metal organic framework material prepared in step (1) and polyvinylidene fluoride to a solvent to obtain a mixed solution; (3) The mixed solution obtained in step (2) is modified onto a glass fiber membrane by suction filtration, and after drying, a glass fiber membrane modified with a bismuth-based metal organic framework material is obtained.

2. The method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material according to claim 1, wherein: In step (1), the feeding amounts of bismuth nitrate pentahydrate and trimesic acid are 50-250 mg and 500-900 mg respectively.

3. The method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material according to claim 1, wherein: In step (1), the temperature of the solvent thermal reaction is 100-130° C., and the time is 20-30 h.

4. The method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material according to claim 1, wherein: In step (2), the total concentration of bismuth-based metal organic framework material and polyvinylidene fluoride in the mixed solution is 1-10 mg·mL -1 .

5. The method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material according to claim 1, wherein: In step (3), the loading amount of the bismuth-based metal organic framework material on the glass fiber diaphragm modified by the bismuth-based metal organic framework material is 1-3 mg cm -2 .

6. The method for preparing a glass fiber diaphragm modified with a bismuth-based metal organic framework material according to claim 5, characterized in that: The loading amount of the bismuth-based metal organic framework material on the glass fiber membrane modified by the bismuth-based metal organic framework material is 2.2-2.6 mg cm -2 .

7. A glass fiber diaphragm modified with a bismuth-based metal organic framework material obtained by the preparation method according to any one of claims 1 to 6.

8. Use of a glass fiber separator modified with the bismuth-based metal-organic framework material according to claim 7 in a zinc ion battery.

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