Multifunctional composite nanofiber membrane as well as preparation method and application thereof

Abstract

The invention discloses a multifunctional composite nanofiber membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out sulfonation treatment on polyether-ether-ketone to obtain sulfonated polyether-ether-ketone; sulfonated polyetheretherketone, a functional additive, a soluble polymer and an organic solvent are uniformly mixed to form a homogeneous suspension, the homogeneous suspension is used as a spinning solution for air spinning to prepare a nanofiber membrane, and then a nano metal membrane is deposited to prepare the multifunctional composite nanofiber membrane. The diameter distribution of the fiber porous structure in the multifunctional composite nanofiber membrane is uniform, the multifunctional composite nanofiber membrane has good electrolyte wettability, can maintain high porosity, ensures the electrochemical performance of the multifunctional composite nanofiber membrane used for assembling the zinc ion battery, has good zinc stripping deposition reversibility, can inhibit dendritic crystal growth, homogenizes a negative electrode interface electric field, and improves the electrochemical performance of the zinc ion battery. The service time of large current is prolonged, the battery capacity is expanded, the long cycle life of the aqueous zinc ion battery is realized, the use cost is reduced, and the volume energy density of the battery is improved.

Description

Technical Field

[0001] The present invention relates to a nanofiber membrane, in particular to a multifunctional composite nanofiber membrane and a preparation method and application thereof, belonging to the field of new energy technology. Background Art

[0002] In recent years, with the increase in fossil energy consumption, serious environmental problems have arisen worldwide, which has promoted people's interest in how to efficiently utilize clean and sustainable energy. Aqueous zinc-ion batteries have a safe and green operating environment, abundant zinc source supply (about 300 times that of lithium), and high theoretical capacity (820 mAh g -1 ) and other advantages, making it a strong competitor in the field of large-scale energy storage. Despite such attractive advantages, the research on aqueous zinc-ion batteries is still affected by coupled degradation problems such as dendrite growth, hydrogen evolution, and corrosion, which together affect the sustainable operation of the battery. During use, zinc ions deposit and dissolve on the surface of the zinc electrode to form zinc dendrites, which pierce the diaphragm, causing the battery to short-circuit and fail, seriously restricting the commercialization progress of aqueous zinc-ion batteries. Summary of the invention

[0003] The main purpose of the present invention is to provide a high-stability multifunctional composite nanofiber membrane and a preparation method thereof, so as to overcome the deficiencies in the prior art.

[0004] Another object of the present invention is to provide an application of the multifunctional composite nanofiber membrane in an aqueous zinc ion battery.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] The present invention provides a method for preparing a multifunctional composite nanofiber membrane, which comprises:

[0007] Sulfonating the polyetheretherketone to obtain sulfonated polyetheretherketone;

[0008] The sulfonated polyetheretherketone, the functional additive, the soluble polymer and the organic solvent are uniformly mixed to form a homogeneous suspension;

[0009] Using the homogeneous suspension as a spinning solution to perform air-spinning to obtain a nanofiber membrane;

[0010] A nano-metal film is deposited on the surface of the nano-fiber membrane to prepare a multifunctional composite nano-fiber membrane.

[0011] In some embodiments, the spinning voltage of the airflow spinning is 8-14 kV, the receiving distance is 15-20 cm, the syringe push speed is 0.1-0.3 ml / min, and vacuum drying is performed at 60-80° C. for 10-14 h to obtain a nanofiber membrane.

[0012] The embodiment of the present invention also provides a multifunctional composite nanofiber membrane prepared by the aforementioned preparation method.

[0013] The embodiment of the present invention also provides the use of the multifunctional composite nanofiber membrane in the preparation of an aqueous zinc ion battery.

[0014] Correspondingly, an embodiment of the present invention further provides an aqueous zinc ion battery, which includes the aforementioned multifunctional composite nanofiber membrane.

[0015] Compared with the prior art, the beneficial effects of the present invention are at least:

[0016] 1) The fiber porous structure in the multifunctional composite nanofiber membrane prepared by the present invention has uniform diameter distribution, good electrolyte wettability, and can maintain a high porosity, thereby ensuring its electrochemical performance for assembling zinc ion batteries, having good zinc stripping deposition reversibility, and can effectively prevent the zinc negative electrode from generating zinc dendrites during continuous charge and discharge, prevent the diaphragm from being punctured, homogenize the negative electrode interface electric field, extend the use time of large current, expand the battery capacity, achieve a long cycle life of the aqueous zinc ion battery, reduce the use cost of the battery and improve the volume energy density of the battery;

[0017] 2) The multifunctional composite nanofiber membrane of the present invention integrates the dual functions of a diaphragm and a negative electrode current collector, avoids the use of a metal zinc-based current collector and a commercial glass fiber diaphragm, and effectively reduces the polarization voltage after copper plating, reduces the mass of the battery, and improves the battery energy density. The diaphragm-free aqueous zinc ion battery improves the zinc deposition behavior, facilitates the diffusion of zinc ions on the negative electrode, and inhibits dendrites, hydrogen evolution, and passivation of the negative electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is an electron microscope element distribution (EDS) image of the multifunctional composite nanofiber membrane prepared in Example 1 of the present invention.

[0020] Figure 2 This is a physical picture of the multifunctional composite nanofiber film prepared in Example 1 of the present invention after magnetron sputtering.

[0021] Figure 3 This is a schematic diagram of the long-cycle results of commercial glass fiber diaphragms.

[0022] Figure 4 It is a schematic diagram of the long-cycle results of the multifunctional composite nanofiber membrane prepared in Example 1 of the present invention.

[0023] Figure 5 It is a polarization curve diagram of the multifunctional composite nanofiber membrane prepared in Example 1 of the present invention.

[0024] Figure 6 This is the impedance spectrum of the multifunctional composite nanofiber membrane prepared in Example 1 of the present invention before and after polarization.

[0025] Figure 7 It is a schematic diagram of the long-cycle results of the multifunctional composite nanofiber membrane prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0026] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice, which mainly involves preparing a multifunctional composite nanofiber membrane and a preparation method thereof. The multifunctional composite nanofiber membrane provided by the present invention has excellent mass transfer effect and can effectively prevent the zinc negative electrode from generating zinc dendrites during continuous charging and discharging, and prevent the diaphragm from being punctured.

[0027] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Specifically, as one aspect of the technical solution of the present invention, a method for preparing a multifunctional composite nanofiber membrane includes:

[0029] Sulfonating the polyetheretherketone to obtain sulfonated polyetheretherketone;

[0030] The sulfonated polyetheretherketone, the functional additive, the soluble polymer and the organic solvent are uniformly mixed to form a homogeneous suspension;

[0031] Using the homogeneous suspension as a spinning solution to perform air-spinning to obtain a nanofiber membrane;

[0032] A nano-metal film is deposited on the surface of the nano-fiber membrane to prepare a multifunctional composite nano-fiber membrane.

[0033] In some embodiments, the preparation method specifically comprises: subjecting polyetheretherketone to sulfonation treatment in concentrated sulfuric acid, and drying to obtain the sulfonated polyetheretherketone.

[0034] Furthermore, the drying includes vacuum drying, and the drying time is 60-80°C.

[0035] In some embodiments, the sulfonation treatment time is 6 to 8 hours.

[0036] In some embodiments, the functional additive may include any one or a combination of two or more of β-cyclodextrin, α-cyclodextrin, γ-cyclodextrin, sodium dodecyl sulfonate, sodium benzene sulfonate, etc., but is not limited thereto. The functional additive used in the present invention can limit the movement of anions, promote the transmission of zinc ions, and increase the transfer number of zinc ions by using the functional groups on organic molecules.

[0037] In some embodiments, the mass ratio of the sulfonated polyetheretherketone, the functional additive and the soluble polymer is 1:1:1 to 3:1:1.

[0038] In some embodiments, the preparation method specifically comprises: dissolving sulfonated polyetheretherketone, functional additives and soluble polymers in an organic solvent, stirring for a certain period of time until they are evenly dispersed, and obtaining a homogeneous suspension.

[0039] Furthermore, the stirring time is 10 to 18 hours.

[0040] In some embodiments, the soluble polymer may include at least any one of PEG, PEO, PAN, etc., but is not limited thereto.

[0041] In some embodiments, the organic solvent includes any one or a mixture of two or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), acetone, N-methylpyrrolidone (NMP), hexafluoroisopropanol (HFIP), tetrahydrofuran, etc., but is not limited thereto.

[0042] In some embodiments, the mass content of the sum of sulfonated polyetheretherketone, functional additives and soluble polymers in the homogeneous suspension is 10% to 25%. In other words, the total mass of the above three substances (i.e., solutes) dissolved in the organic solvent should maintain a certain solid-liquid ratio, and the mass of the solute is 10% to 25%.

[0043] In some embodiments, the spinning voltage of the air flow spinning used in the present invention is 8-14 kV, the receiving distance is 15-20 cm, the injection pump push speed (i.e. the flow rate of the suspension) is 0.1-0.3 ml / min, and vacuum drying is performed at 60-80°C for 10-14 hours to produce a nanofiber membrane.

[0044] In some embodiments, the air flow velocity of the air flow spinning used in the present invention is 20m / s to 400m / s, the angle between the air outlet direction and the horizontal plane is 10° to 15°, and the size of the air outlet gap is 2mm to 10mm.

[0045] In some embodiments, the preparation method specifically includes: using a magnetron sputtering method to deposit a nanometal film on the surface of the nanofiber membrane to prepare a multifunctional composite nanofiber membrane.

[0046] In some embodiments, the material of the nanometal film can be a p-zone or d-zone metal single substance such as copper, silver, tin, antimony, bismuth, or a binary, ternary, or other multi-element alloy composed of them, but is not limited thereto.

[0047] Furthermore, the shape of the nano-metal film may be any one of a circle, a square, a rectangle, etc., or other special shapes, but is not limited thereto.

[0048] In some embodiments, the magnetron sputtering has a flow rate of 10-120 sccm, a pressure of 2-5 Pa, and a power of 200-300W.

[0049] In some embodiments, the preparation method specifically includes: arranging a plurality of nanofiber membranes at a set distance to form a nanofiber membrane array, and then depositing a nanometal film on the surface of the nanofiber membrane by magnetron sputtering. Wherein, during magnetron sputtering, the circular diameter or square side length of the nanometal film is 10 to 25 mm, and the distance between two adjacent nanometal films is 5 to 30 mm.

[0050] In some embodiments, the thickness of the nanometal film is 100-1500 nm.

[0051] Among them, in some more specific embodiments, the specific steps of the method for preparing the multifunctional composite nanofiber membrane are as follows:

[0052] S1: PEEK (polyetheretherketone) powder is placed in concentrated sulfuric acid for sulfonation for 6 to 8 hours, and then the solution is dropped into deionized water. After a large amount of washing, it is vacuum dried at 60 to 80° C. to obtain SPEEK powder (sulfonated polyetheretherketone).

[0053] S2: SPEEK, functional additives (such as β-cyclodextrin) and soluble polymers are dissolved in an organic solvent at a molar ratio of 1:1:1 to 3:1:1, and after stirring for 10 to 18 hours, they are evenly dispersed to obtain a homogeneous suspension.

[0054] S3: The obtained solution is subjected to air-spinning through an 18-gauge needle, the spinning voltage is 8-14 kV, the receiving distance is 15-20 cm, the syringe push speed is 0.1-0.3 ml / min, and then vacuum dried at 60-80°C for 10-14 hours to obtain a nanofiber membrane.

[0055] S4: depositing a nano-metal film on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a zinc-free negative electrode multifunctional composite nanofiber membrane.

[0056] In summary, the present invention adopts the method of airflow-assisted electric field to prepare nanofiber composite membrane, uses functional groups to regulate the electric field, and uses the difference in electronegativity of functional groups to guide Zn 2+ Uniform deposition on the sputtered metal film; and the magnetron sputtered metal film used in the present invention effectively reduces the polarization voltage and can extend the service life. In addition, the present invention utilizes the synergistic effect between materials and attracts ion migration through the properties of sulfonic acid and Zn affinity.

[0057] Another aspect of the embodiments of the present invention further provides a multifunctional composite nanofiber membrane prepared by the aforementioned preparation method.

[0058] Furthermore, the multifunctional composite nanofiber membrane has a thickness of 10 to 200 μm, preferably 25 to 150 μm, a porosity of 40 to 80%, and a pore size of 100 to 200 nm.

[0059] The present invention provides a new nanofiber composite membrane that can act as both a diaphragm and a current collector, integrating the diaphragm, current collector, and electrode into an integrated design. The present invention accelerates the transfer of Zn while limiting the transmission of anions. 2+ transport, transporting along the nanopores, reducing the polarization voltage.

[0060] Furthermore, the nanofiber membrane prepared by the present invention has a uniform pore diameter distribution, good electrolyte wettability, and can maintain a high porosity, thereby ensuring its electrochemical performance for assembling zinc ion batteries, having good zinc stripping deposition reversibility, and can inhibit dendrite growth, homogenize the negative electrode interface electric field, extend the use time of large currents, expand the battery capacity, achieve a long cycle life of aqueous zinc ion batteries, reduce the battery's use cost and improve the battery's volume energy density.

[0061] In summary, the multifunctional composite nanofiber membrane of the present invention integrates the dual functions of the separator and the negative electrode current collector, avoids the use of metal zinc-based current collectors and commercial glass fiber separators, and effectively reduces the polarization voltage after copper plating, reduces the mass of the battery, and improves the battery energy density. The separator-free aqueous zinc ion battery improves the zinc deposition behavior and facilitates the diffusion of zinc ions on the negative electrode. Dendrites, hydrogen evolution and passivation of the negative electrode are suppressed.

[0062] The carboxyl, carbonyl and hydroxyl functional groups in the multifunctional composite nanofiber membrane current collector of the present invention can effectively chelate zinc ions, and accelerate the transport of zinc ions by utilizing the electronegativity difference. The anions are confined in the ring-shaped cyclodextrin molecular structure due to the size effect and hydrogen bonding effect, or their transfer is restricted by the functional groups in the molecular chain, and Zn 2+It can be guided to form a single Zn ion migration channel, while blocking the anions from reaching the surface of the sputtered Cu, homogenizing the interfacial electric field and having a depolarization effect.

[0063] The multifunctional composite nanofiber membrane of the present invention weakens the H 2 The activity of O and Zn is regulated, the electric field is adjusted, and the zinc ions are uniformly deposited. At the same time, the composite membrane of the aqueous zinc ion battery can effectively prevent the growth of dendrites from being pierced during the charge and discharge process, extend the service life under high current, and improve the battery capacity. At the same time, the zinc deposition behavior during the cycle is regulated, the ionic conductivity of the composite membrane is effectively improved, and the electrochemical performance of the aqueous zinc ion battery is improved.

[0064] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention. The experimental methods in the following embodiments that do not specify specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer.

[0065] Example 1

[0066] PEEK powder was placed in concentrated sulfuric acid for sulfonation for 6 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 80°C to obtain SPEEK powder. SPEEK, β-cyclodextrin and PAN were dissolved in DMF at a mass ratio of 1:1:1, with a solute mass of 10%. After stirring for 14 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, the spinning voltage was 12kV, the receiving distance was 20cm, the flow rate of the homogeneous suspension was 0.03ml / min, the air flow velocity was 100m / s, the angle between the outlet direction and the horizontal plane was 15°, the outlet gap size was 10mm, and the nanofiber membrane was obtained after vacuum drying at 80°C for 12h. The nanofiber membrane was deposited on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 100sccm, the pressure was 5Pa, the power was 300W, and the thickness of the nanocopper membrane was 150nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally obtained is 100 μm, and the porosity is 60%. The diameter of the nano copper membrane during magnetron sputtering is 14 mm, and the distance between each membrane is 20 mm.

[0067] The electron microscope EDS image of the multifunctional composite nanofiber membrane obtained in this example is as follows: Figure 1 As shown, the actual picture after magnetron sputtering is as follows Figure 2 shown.

[0068] Example 2

[0069] PEEK powder was placed in concentrated sulfuric acid for sulfonation for 8 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 80°C to obtain SPEEK powder. SPEEK, β-cyclodextrin and PEO were dissolved in acetone at a molar ratio of 2:1:1, with a solute mass of 10%. After stirring for 14 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, with a spinning voltage of 10kV, a receiving distance of 20cm, a flow rate of the homogeneous suspension of 0.03ml / min, an air flow velocity of 200m / s, an angle of 15° between the outlet direction and the horizontal plane, an outlet gap size of 8mm, and vacuum dried at 60°C for 12h to obtain a nanofiber membrane. A nanocopper film was deposited on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 100sccm, the pressure was 4Pa, the power was 200W, and the thickness of the nanocopper film was 1500nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally prepared is 75 μm, and the porosity is 80%. The diameter of the nano copper membrane during magnetron sputtering is 14 mm, and the distance between each membrane is 20 mm.

[0070] Example 3

[0071] PEEK powder was sulfonated in concentrated sulfuric acid for 8 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 80°C to obtain SPEEK powder. SPEEK, β-cyclodextrin and PAN were dissolved in DMF at a mass ratio of 1:1:1, with a solute mass of 10%. After stirring for 14 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, with a spinning voltage of 12kV, a receiving distance of 20cm, a flow rate of the homogeneous suspension of 0.03ml / min, an air flow velocity of 200m / s, an angle of 10° between the outlet direction and the horizontal plane, an outlet gap size of 8mm, and vacuum dried at 80°C for 12h to obtain a nanofiber membrane. A nanocopper film was deposited on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 100sccm, the pressure was 5Pa, the power was 300W, and the thickness of the nanocopper film was 1500nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally obtained is 100 μm, and the porosity is 70%. The diameter of the nano copper membrane during magnetron sputtering is 14 mm, and the distance between each membrane is 25 mm.

[0072] Example 4

[0073] PEEK powder was sulfonated in concentrated sulfuric acid for 8 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 80°C to obtain SPEEK powder. SPEEK, β-cyclodextrin and PEG were dissolved in DMAC at a molar ratio of 1:1:1, with a solute mass of 10%. After stirring for 14 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, with a spinning voltage of 12kV, a receiving distance of 20cm, a flow rate of the homogeneous suspension of 0.03ml / min, an air flow velocity of 100m / s, an angle of 12° between the outlet direction and the horizontal plane, an outlet gap size of 8mm, and vacuum dried at 80°C for 12h to obtain a nanofiber membrane. A nanocopper film was deposited on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 100sccm, the pressure was 5Pa, the power was 300W, and the thickness of the nanocopper film was 1500nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally obtained is 100 μm, and the porosity is 60%. The diameter of the nano copper membrane during magnetron sputtering is 14 mm, and the distance between each membrane is 20 mm.

[0074] Example 5

[0075] PEEK powder was placed in concentrated sulfuric acid for sulfonation for 8 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 80°C to obtain SPEEK powder. SPEEK, β-cyclodextrin and PAN were dissolved in acetone at a molar ratio of 1:1:1, with a solute mass of 10%. After stirring for 14 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, the spinning voltage was 12kV, the receiving distance was 20cm, the flow rate of the homogeneous suspension was 0.03ml / min, the air flow velocity was 100m / s, the angle between the outlet direction and the horizontal plane was 15°, the outlet gap size was 8mm, and the nanofiber membrane was obtained after vacuum drying at 80°C for 12h. A nano-Ag film was deposited on the surface of the obtained nanofiber membrane by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 100sccm, the pressure was 5Pa, the power was 300W, and the thickness of the nano-copper film was 1500nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally obtained is 100 μm, and the porosity is 65%. The diameter of the nano copper membrane during magnetron sputtering is 14 mm, and the distance between each membrane is 20 mm.

[0076] Example 6

[0077] PEEK powder was placed in concentrated sulfuric acid for sulfonation for 7 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 70°C to obtain SPEEK powder. SPEEK, α-cyclodextrin and PAN were dissolved in N-methylpyrrolidone at a molar ratio of 3:1:1, with a solute mass of 20%. After stirring for 10 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, the spinning voltage was 14kV, the receiving distance was 18cm, the flow rate of the homogeneous suspension was 0.02ml / min, the air flow velocity was 400m / s, the angle between the outlet direction and the horizontal plane was 10°, the outlet gap size was 8mm, and the nanofiber membrane was obtained after vacuum drying at 80°C for 10h. The surface of the obtained nanofiber membrane was deposited with a nano-Sn film by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 120sccm, the pressure was 2Pa, the power was 250W, and the thickness of the nano-copper film was 1000nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally prepared is 200 μm, and the porosity is 55%. The diameter of the nano copper membrane during magnetron sputtering is 10 mm, and the distance between each membrane is 5 mm.

[0078] Example 7

[0079] PEEK powder was placed in concentrated sulfuric acid for sulfonation for 8 hours, and then the solution was dripped into deionized water, washed in large quantities, and vacuum dried at 60°C to obtain SPEEK powder. SPEEK, γ-cyclodextrin and PAN were dissolved in tetrahydrofuran at a molar ratio of 2:1:1, with a solute mass of 25%. After stirring for 18 hours, they were evenly dispersed to obtain a homogeneous suspension. The obtained solution was air-spun using an 18-gauge needle, the spinning voltage was 8kV, the receiving distance was 15cm, the flow rate of the homogeneous suspension was 0.01ml / min, the air flow velocity was 20m / s, the angle between the outlet direction and the horizontal plane was 15°, the outlet gap size was 2mm, and the nanofiber membrane was obtained after vacuum drying at 60°C for 14h. The surface of the obtained nanofiber membrane was deposited with a nano-Sb film by magnetron sputtering to obtain a composite nanofiber membrane. The magnetron sputtering flow rate was 10sccm, the pressure was 3Pa, the power was 200W, and the thickness of the nano-copper film was 100nm. The thickness of the zinc-free negative electrode multifunctional composite nanofiber membrane finally obtained is 10 μm, and the porosity is 40%. The diameter of the nano copper membrane during magnetron sputtering is 25 mm, and the distance between each membrane is 30 mm.

[0080] Comparative Example 1

[0081] Commercial glass fiber separators were directly used to assemble zinc-copper batteries for testing.

[0082] Comparative Example 2

[0083] Compared with Example 1, the difference of this comparative example is that the zinc-copper battery is assembled and tested without sputtering copper.

[0084] Comparative Example 3

[0085] Compared with Example 1, the difference of this comparative example is that no sulfonated polyetheretherketone is added to the homogeneous suspension for electrospinning, and a zinc-copper battery is assembled for testing.

[0086] Comparative Example 4

[0087] Compared with Example 1, the difference of this comparative example is that unsulfonated polyetheretherketone is directly added to the homogeneous suspension for electrospinning, and a zinc-copper battery is assembled for testing.

[0088] Comparative Example 5

[0089] Compared with Example 1, the difference of this comparative example is that no β-cyclodextrin is added to the homogeneous suspension for electrospinning, and a zinc-copper battery is assembled for testing.

[0090] Test Case

[0091] In order to verify the technical effect obtained by the present invention, the multifunctional composite nanofiber membranes obtained in Examples 1-5 and Comparative Examples 1-5 were tested respectively, and the specific results are shown in Table 1:

[0092] Mechanical properties: First, cut the sample to be tested into a rectangle of 5mm×20mm, measure the sample thickness on a thickness gauge, and take the average value after 50 measurements. The pre-tension during the test is 0.01N, the maximum stretching length is 25mm, and the stretching speed is 15mm / min.

[0093] PEIS: Frequency 10 6 Up to 10 -1 Hz, and the potential amplitude was 5 mV.

[0094] CA: overpotential 10mV; test time 3600s.

[0095] The constant current charge and discharge of the battery at a current density of 1mA lmAh. All experiments were carried out at room temperature of 25℃.

[0096] Table 1 Relevant performance parameters of the measured materials

[0097] Sample Tensile strength / MPa Ion mobility Short circuit life / h Example 1 7.1 0.72 1400 Example 2 6.5 0.54 1600 Example 3 6.9 0.65 1700 Example 4 7.5 0.63 1200 Example 5 6.6 0.59 1300 Comparative Example 1 5.7 0.38 240 Comparative Example 2 4.6 0.47 500 Comparative Example 3 5.4 0.36 800 Comparative Example 4 6.7 0.42 700 Comparative Example 5 5.4 0.44 650

[0098] Figure 3 This is a schematic diagram of the long-cycle results of the commercial glass fiber separator in Example 1. Figure 4 is a schematic diagram of the long-cycle results of the multifunctional composite nanofiber membrane prepared in Example 1, Figure 5 and Figure 6is a schematic diagram of the ion mobility of the multifunctional composite nanofiber membrane prepared in Example 1, wherein: Figure 5 is the polarization curve diagram, Figure 6 The impedance spectrum before and after polarization. Figure 5 and Figure 6 The data in can be used to calculate the migration number of zinc ions, which indirectly reflects the advantages of the multifunctional composite nanofiber membrane structure and performance synergistic design of the present invention in enhancing ion migration. Figure 7 This is a schematic diagram of the long-cycle results of the multifunctional composite nanofiber membrane prepared in Example 2.

[0099] In addition, the inventor of this case also conducted experiments with other raw materials and conditions listed in this specification with reference to the methods of Examples 1 to 7, and obtained the same technical effects.

[0100] It should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a multifunctional composite nanofiber membrane, characterized in that: include: Sulfonating the polyetheretherketone to obtain sulfonated polyetheretherketone; The sulfonated polyetheretherketone, the functional additive, the soluble polymer and the organic solvent are uniformly mixed to form a homogeneous suspension; Using the homogeneous suspension as a spinning solution to perform air-spinning to obtain a nanofiber membrane; A nano-metal film is deposited on the surface of the nano-fiber membrane to prepare a multifunctional composite nano-fiber membrane.

2. The preparation method according to claim 1, characterized in that: include: The polyetheretherketone is placed in concentrated sulfuric acid for sulfonation treatment, and then dried to obtain the sulfonated polyetheretherketone; And / or, the sulfonation treatment time is 6 to 8 hours; Preferably, the drying comprises vacuum drying, and the drying time is 60-80°C.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the sulfonated polyetheretherketone, the functional additive and the soluble polymer is 1:1:1 to 3:1:

1.

4. The preparation method according to claim 1, characterized in that: include: Dissolve the sulfonated polyetheretherketone, functional additives and soluble polymer in an organic solvent, and stir until uniformly dispersed to obtain a homogeneous suspension; preferably, the stirring time is 10 to 18 hours; And / or, the functional additive includes any one of β-cyclodextrin, α-cyclodextrin, γ-cyclodextrin, sodium dodecyl sulfate, and sodium benzenesulfonate, or a combination of two or more thereof.

5. The preparation method according to claim 1, characterized in that: The soluble polymer includes at least any one of PEG, PEO, and PAN; and / or the organic solvent includes any one of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, N-methylpyrrolidone, hexafluoroisopropanol, and tetrahydrofuran, or a mixture of two or more thereof; And / or, the mass content of the sum of sulfonated polyetheretherketone, functional additives and soluble polymer in the homogeneous suspension is 10% to 25%.

6. The preparation method according to claim 1, characterized in that: The spinning voltage of the air spinning is 8-14 kV, the receiving distance is 15-20 cm, the syringe push speed is 0.01-0.03 ml / min, and the nanofiber membrane is prepared by vacuum drying at 60-80° C. for 10-14 hours. And / or, the air flow velocity of the air flow spinning is 20m / s to 400m / s, the angle between the air outlet direction and the horizontal plane is 10° to 15°, and the size of the air outlet gap is 2mm to 10mm.

7. The preparation method according to claim 1, characterized in that: include: A nano-metal film is deposited on the surface of the nano-fiber membrane by a magnetron sputtering method to prepare a multifunctional composite nano-fiber membrane; And / or, the material of the nanometal film includes a p-region or d-region metal element, or at least any one of a binary alloy or a ternary alloy of a metal element; preferably, the p-region or d-region metal element includes at least any one of copper, silver, tin, antimony, and bismuth; And / or, the shape of the nanometal film includes any one of a circle, a square, and a rectangle; Preferably, the magnetron sputtering has a flow rate of 10 to 120 sccm, a pressure of 2 to 5 Pa, and a power of 200 to 300 W; Preferably, the preparation method specifically comprises: arranging a plurality of nanofiber membranes at a set distance to form a nanofiber membrane array, and then depositing a nanometal film on the surface of the nanofiber membrane by a magnetron sputtering method; Particularly preferably, the circular diameter or square side length of the nanometal film is 10 to 25 mm, and the distance between two adjacent nanometal films is 5 to 30 mm; And / or, the thickness of the nano metal film is 100-1500 nm.

8. A multifunctional composite nanofiber membrane prepared by the preparation method according to any one of claims 1 to 7; Preferably, the multifunctional composite nanofiber membrane has a thickness of 10 to 200 μm, preferably 25 to 150 μm, a pore size of 100 to 200 nm, and a porosity of 40 to 80%.

9. Use of the multifunctional composite nanofiber membrane according to claim 8 in the preparation of aqueous zinc ion batteries.

10. An aqueous zinc ion battery, characterized in that: Comprising the multifunctional composite nanofiber membrane as described in claim 8.

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