Method for continuously preparing COP-based nanofiber membrane and method for continuously preparing oxygen electrode

Abstract

The invention relates to the technical field of electrochemistry, in particular to a method for continuously preparing a COP-based nanofiber membrane and a method for continuously preparing an oxygen electrode. The preparation method comprises the following steps: (1) performing needleless electrostatic spinning on a spinning dispersion liquid containing a high-molecular polymer, a metal source and a conductive agent; and (2) in the presence of a hydrothermal reaction catalyst, carrying out hydrothermal treatment on the fiber membrane obtained by needleless electrostatic spinning and an organic ligand dispersion liquid containing an organic ligand, and then carrying out post-treatment to obtain the COP-based nanofiber membrane. The method provided by the invention can realize continuous production, and the produced COP-based nanofiber membrane has higher power density and lower overpotential during use.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry technology, and particularly relates to a method for continuously preparing a COP-based nanofiber membrane and a method for continuously preparing an oxygen electrode. Background Art

[0002] Due to the intermittency and instability of renewable energy, large-scale energy storage technologies need to be developed. Although lithium-ion batteries have a relatively high specific energy density (<250 W h kg -1 ) and a large number of charge-discharge cycles, generally, lithium-ion batteries contain flammable organic solutions, and there are safety problems such as spontaneous combustion or explosion when used abnormally or the protection fails. In large-scale energy storage systems, this safety problem is particularly prominent and may evolve into a serious accident that is difficult to bear. Therefore, at this application level, a series of relatively mature alternative batteries, such as metal-air batteries and flow batteries, generally use aqueous solutions as electrolytes to solve the above safety problems.

[0003] At present, the air electrode of the metal-air battery cathode generally consists of three layers: a porous catalytic layer, a conductive current collector, and a waterproof and breathable layer. The porous catalytic layer is the main place where oxygen is reduced. The conductive current collector mainly plays the role of conducting electricity and mechanical support. The waterproof and breathable layer has a loose and porous hydrophobic structure. Among them, the catalytic layer is the core place of the battery reaction, which directly determines the performance of the battery. The catalytic layer needs to have high-efficiency oxygen reduction performance and excellent durability. At present, the preparation process of the catalytic layer mostly uses high-temperature carbonization to prepare powdery catalysts as the active source, and then uniformly configures the catalyst ink and sprays it on the gas diffusion layer. This preparation process is derived from the oxygen electrode preparation process of fuel cells. The commercial catalyst is noble metal Pt / C, which is expensive and the preparation process is complex. Most of the reported transition metal nitrogen-carbon catalysts in the literature are still in the laboratory research and development stage and cannot be prepared on a large scale because the preparation of this type of catalyst requires high-temperature pyrolysis, high energy consumption, and it is difficult to ensure batch stability, and there is a scale-up effect. There is still a lack of a reliable process for the preparation method of the air electrode of the metal-air flow battery. Summary of the Invention

[0004] As described above, in the traditional electrode assembly process, the catalyst and the binder are blended and then attached to the carbon paper or carbon felt as the air electrode matrix by means such as spraying. During the operation of the battery, due to the continuous scouring of the electrolyte and the continuous evolution of oxygen, the catalyst is prone to fall off, flooding, etc., which seriously affects the stability and service life of the air electrode.

[0005] Electrospinning is an efficient and low-cost way to produce nanofibers. The nanofiber membranes prepared by this technology have high consistency, and the technology is mature for the preparation of masks, non-woven fabrics and other materials, and has certain market conditions. Nanofibers have a high aspect ratio and specific surface area as a catalyst carrier; organic covalent polymers have great potential in the field of electrocatalysis due to their unique topological design principles, modular properties and rich elemental composition, and have hydrothermal durability in acidic or alkaline media. They are ideal catalysts for electrocatalytic oxygen reduction, but their two-dimensional layered structure limits the mass transfer channels of oxygen, and the active sites cannot be fully exposed. The oxygen electrodes prepared by traditional spraying or scraping methods have extremely low utilization of the catalyst and cannot exert their intrinsic properties. The inventors of the present invention use electrospinning technology and COP materials to in-situ controllably prepare a theoretically designed multi-level structure catalytic layer with excellent mass transfer, and polymerize transition metal-doped layered organic covalent polymers on the surface of nanofibers through an in-situ self-assembly strategy, thereby achieving a two-dimensional to three-dimensional transformation, improving the utilization rate of the catalyst, accelerating the transfer efficiency of the reaction gas and reaction products, reducing the charge transfer resistance, and achieving the assembly of air battery devices with excellent performance.

[0006] In addition, in industrial production, it is generally hoped that the corresponding products can be prepared continuously in large quantities.

[0007] Based on this, the first aspect of the present invention provides a method for continuously preparing COP-based nanofiber membranes, which preparation method comprises: (1) subjecting a spinning dispersion containing a high molecular weight polymer, a metal source and a conductive agent to needle-free electrospinning; (2) subjecting the fiber membrane obtained by needle-free electrospinning to hydrothermal treatment with an organic ligand dispersion containing an organic ligand in the presence of a hydrothermal reaction catalyst, and then performing post-treatment to obtain a COP-based nanofiber membrane.

[0008] The second aspect of the present invention provides a method for continuously preparing an oxygen electrode. The preparation method comprises: preparing a COP-based nanofiber membrane according to the method for preparing a COP-based nanofiber membrane of the present invention, and then compounding the prepared COP-based nanofiber membrane with a gas diffusion layer to obtain an oxygen electrode.

[0009] Compared with the prior art, the present invention has at least the following beneficial effects:

[0010] (1) The prior art uses high-temperature carbonization to prepare catalysts, which consumes a lot of energy. It is difficult to ensure temperature consistency in batch preparation, which leads to low consistency of the catalyst. The hydrothermal method used in the present invention to load the catalyst layer has low energy consumption, simple process and can be produced continuously, and has high commercial potential.

[0011] (2) In the prior art, the method for preparing the oxygen electrode catalytic layer is to spray or scrape the catalyst powder, which is prone to fall off and fail after being washed by the electrolyte in the flow battery. It has a high space-time yield during production, and the produced COP-based nanofiber membrane has a higher power density and a lower overpotential during use. Description of the Drawings

[0012] Figure 1 is the oxygen electrode prepared in Example 1;

[0013] Figure 2 is the charge-discharge cycle diagram of the zinc-air flow battery with the oxygen electrode in Example 1. Detailed Embodiments

[0014] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0015] The first aspect of the present invention provides a method for continuously preparing a COP-based nanofiber membrane, and the preparation method includes: (1) performing needleless electrospinning on a spinning dispersion liquid containing a polymer, a metal source, and a conductive agent; (2) performing hydrothermal treatment on the fiber membrane obtained by needleless electrospinning and an organic ligand dispersion liquid containing an organic ligand in the presence of a hydrothermal reaction catalyst, and then performing post-treatment to obtain a COP-based nanofiber membrane.

[0016] In the present invention, through the electrospinning technology, a mass transfer excellent hierarchical structure catalytic layer designed theoretically is in-situ controllably prepared by using COP materials, a highly ordered catalyst / electrolyte / oxygen three-phase reaction interface is constructed, and a highly consistent "catalysis - mass transfer" integrated air COP-based nanofiber membrane with a hierarchical porous network structure of high permeability, high porosity, and high specific surface area is obtained, improving the utilization rate of the catalyst, accelerating the transfer efficiency of reaction gases and reaction products, and reducing the charge transfer resistance.

[0017] According to the present invention, as long as the purpose of the present invention can be achieved, the specific type of the polymer is not particularly limited as long as a fiber membrane can be spun. The polymer is divided into water-soluble polymers and water-insoluble polymers according to whether it can be dissolved or swollen in water. In order to make the COP-based nanofiber membrane insoluble in water, the content of the water-soluble polymer in the polymer is not higher than 50 wt%, for example, 0 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, and preferably 0 - 40 wt%

[0018] According to a preferred embodiment of the present invention, the polymer is selected from nitrogen-containing polymers and / or non-nitrogen-containing polymers. By adopting the foregoing embodiment, the final COP-based nanofiber membrane has a higher power density and a lower overpotential when in use.

[0019] According to a preferred embodiment of the present invention, the number-average molecular weight of the polymer is 60,000 - 1,500,000, such as 60,000, 150,000, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 1,000,000, 1,200,000, 1,500,000.

[0020] According to a more preferred embodiment of the present invention, the polymer is selected from nitrogen-containing polymers and non-nitrogen-containing polymers. The COP-based nanofiber membrane prepared by the foregoing embodiment has better catalytic stability, a higher power density and a lower overpotential.

[0021] According to a more preferred embodiment of the present invention, the mass ratio of the nitrogen-containing polymer to the non-nitrogen-containing polymer is 1:(1 - 6), such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6. The COP-based nanofiber membrane prepared by the foregoing embodiment has better catalytic stability, a higher power density and a lower overpotential.

[0022] The nitrogen-containing polymer in the present invention means that the nitrogen-containing polymer contains nitrogen elements. Preferably, the nitrogen content of the nitrogen-containing polymer is 10wt% - 30wt%, such as 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 26wt%, 30wt%.

[0023] According to the present invention, as long as the object of the present invention can be achieved, the type of the nitrogen-containing polymer is not particularly limited, and any spinnable nitrogen-containing polymer in the art can be used. In a preferred embodiment, the nitrogen-containing polymer is selected from at least one of polyurethane, polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethyleneimine and polyetherimide, preferably at least one of polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethyleneimine and polyetherimide. Specifically, in the examples of the present invention, several specific nitrogen-containing polymers such as polyvinylpyrrolidone, polyacrylonitrile and polyetherimide are used to exemplify the advantages of the present invention, but should not be construed as a limitation to the present invention.

[0024] According to the present invention, there is no special limitation on the specific type of the non-nitrogen-containing polymer. Any spinnable non-nitrogen-containing polymer in the art is suitable for the present invention. In a preferred embodiment, the non-nitrogen-containing polymer is selected from at least one of polytetrafluoroethylene, polyvinylidene chloride, polyvinylidene fluoride, polystyrene, polyvinyl alcohol, polyethylene oxide, and polyacrylic acid. Specifically, in the examples of the present invention, the advantages of the present invention are illustrated by several specific non-nitrogen-containing polymers such as polyvinylidene fluoride and polystyrene, but it should not be construed as a limitation to the present invention.

[0025] According to the present invention, as long as the object of the present invention can be achieved, there is no special limitation on the specific type of the metal source. Preferably, the metal source is selected from the inorganic metal salts corresponding to the transition metals respectively.

[0026] According to a preferred embodiment of the present invention, the inorganic metal salt is an inorganic metal salt without crystal water. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better catalytic stability, higher power density, and lower overpotential.

[0027] According to the present invention, as long as the object of the present invention can be achieved, there is no special limitation on the type of the metal. In a preferred embodiment, the transition metal is selected from at least one of iron, cobalt, manganese, nickel, and copper. In the present invention, the advantages of the present invention are illustrated by iron and / or cobalt, but the present invention is not limited thereto.

[0028] According to the present invention, as long as the object of the present invention can be achieved, there is no special limitation on the specific type of the conductive agent. Preferably, the conductive agent is selected from at least one of carbon black, carbon nanotubes, polyaniline, graphite, graphene, and copper powder, and preferably at least one of carbon black, graphite, and graphene.

[0029] According to a preferred embodiment of the present invention, the shape of the conductive agent is at least one of spherical, columnar, tubular, and layered, and preferably spherical and / or sheet-like.

[0030] According to a preferred embodiment of the present invention, the particle size of the conductive agent is 10 - 300 nm, preferably 20 - 120 nm. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better catalytic stability, higher power density, and lower overpotential.

[0031] According to the present invention, as long as the object of the present invention can be achieved, the type of the hydrothermal reaction catalyst is not particularly limited, and any compound capable of promoting the Schiff base reaction polymerization of an organic ligand to form a COP configuration is applicable to the system of the present invention. Preferably, the hydrothermal reaction catalyst is selected from compounds capable of promoting the Schiff base reaction polymerization of an organic ligand to form a COP configuration, and preferably selected from at least one of sodium acetate, 1,8-diazabicyclo[5,4,0]undec-7-ene, 2,2-dimethyl-1,3-dioxepan-5-one, and 1,4,7-triazacyclononane.

[0032] As a more preferred technical solution of the present invention, the hydrothermal reaction catalyst is at least one of 1,8-diazabicyclo[5,4,0]undec-7-ene, 2,2-dimethyl-1,3-dioxepan-5-one, and 1,4,7-triazacyclononane.

[0033] According to the present invention, the organic ligand can form a coordinated metal activity with the metal in the metal source, and COP is polymerized by the Schiff base reaction of the organic ligand. Preferably, the organic ligand contains nitrogen. By adopting the foregoing embodiments, metal active centers containing nitrogen coordination and well-defined oxygen reduction sites such as electronegative heteroatoms can be directionally introduced into the topological skeleton of COP.

[0034] In a preferred embodiment of the present invention, the organic ligand is selected from one or more of 2,3,6,7,10,11-hexaminotriphenyl hexahydrochloride, 1,2-dicyanobenzene, 1,3,5-tris(4-aminophenyl)benzene, 3,5-diphenylbiphenyl-4-amine, 1,2,4,5-tetracyanobenzene, 2,3,5,6-tetrafluoroterephthalonitrile, and 3,4,5,6-tetrafluoroorthophthalonitrile.

[0035] According to the present invention, those skilled in the art can understand that when a polymer is spun, generally the polymer is dissolved in a solvent to form a spinning solution for spinning. That is, the spinning dispersion in the present invention is obtained by dispersing solutes such as a polymer and a conductive agent in a corresponding solvent. The spinning dispersion contains components such as a polymer, a conductive agent, and a solvent. Among them, the solvent can be a conventional solvent in the art. For example, the solvent in the spinning dispersion is selected from at least one of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, dichloroethane, dichloromethane, and tetrahydrofuran.

[0036] In the present invention, the spinning dispersion can be prepared in a conventional manner in the art. For example, a high molecular polymer and a solvent are added to a glass stirring kettle for the first mixing, and then a metal source is added to the glass stirring kettle for continuous second mixing. To make the mixing more uniform, the first mixing and / or the second mixing can be carried out under the conditions of ultrasonic and stirring. For example, the first mixing is carried out under ultrasonic and stirring at 150 - 300 revolutions per minute for 6 - 12 hours, and the second mixing is carried out at 20 - 50 °C and 150 - 300 revolutions per minute for 4 - 6 hours.

[0037] The organic ligand dispersion in the present invention refers to a dispersion formed by dispersing an organic ligand, a reaction catalyst, etc. in a corresponding solvent. The selection of the solvent has no special limitation. For example, the solvent in the organic ligand dispersion is selected from at least one of N, N-dimethylformamide, ethylene glycol, ethanol, methanol, triethanolamine, diethyl ether, water, and chloroform.

[0038] The organic ligand dispersion in the present invention can be prepared by a conventional method in the art. For example, after mixing the organic ligand and the solvent, a reaction catalyst is continuously added dropwise for mixing. To make the mixing more uniform, the mixing can be carried out under stirring conditions.

[0039] According to the present invention, as long as the object of the present invention can be achieved, a fiber membrane with a certain thickness can be prepared as needed. For example, the thickness of the fiber membrane is 0.01 - 0.5 mm, preferably 0.1 - 0.3 mm.

[0040] According to a preferred embodiment of the present invention, in the organic ligand dispersion, the content of the hydrothermal reaction catalyst is 0.5 - 30 wt%, 0.5 wt%, 1 wt%, 1.6 wt%, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, preferably 0.5 - 3 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability, higher power density, and lower overpotential.

[0041] According to a preferred embodiment of the present invention, in the organic ligand dispersion, the content of the organic ligand is 0.5 - 8 wt%, for example, 0.5 wt%, 0.6 wt%, 1 wt%, 1.9 wt%, 2.5 wt%, 3 wt%, 5 wt%, 6 wt%, 8 wt%, preferably 1.5 - 5 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability, higher power density, and lower overpotential.

[0042] According to a preferred embodiment of the present invention, in the spinning dispersion liquid, the content of the polymer is 5-50 wt%, for example, 5 wt%, 12 wt%, 15 wt%, 16 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 50 wt%, preferably 10-30 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability.

[0043] According to a preferred embodiment of the present invention, based on the total mass of the polymer, the metal source and the conductive agent: the content of the polymer is 55-90 wt%, for example, 55 wt%, 60 wt%, 67 wt%, 73 wt%, 77 wt%, 80 wt%, 87 wt%, 90 wt%, preferably 65-85 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability, higher power density and lower overpotential.

[0044] According to a preferred embodiment of the present invention, based on the total mass of the polymer, the metal source and the conductive agent: the content of the metal source is 1-25 wt%, for example, 1 wt%, 5 wt%, 8 wt%, 11 wt%, 13 wt%, 19 wt%, 23 wt%, 25 wt%, preferably 5-20 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability, higher power density and lower overpotential.

[0045] According to a preferred embodiment of the present invention, based on the total mass of the polymer, the metal source and the conductive agent: the content of the conductive agent is 1-25 wt%, for example, 1 wt%, 5 wt%, 8 wt%, 11 wt%, 13 wt%, 16 wt%, 18 wt%, 20 wt%, 25 wt%, preferably 5-20 wt%. By adopting the foregoing embodiment, the prepared COP-based nanofiber membrane has better cycle stability.

[0046] According to the present invention, as long as the object of the present invention can be achieved, the conditions of needleless electrospinning are not particularly limited. Preferably, the conditions of needleless electrospinning include: the positive pressure is 15-45 kV; the negative pressure is -15 to -5 kV.

[0047] According to the present invention, the effective width of needleless electrospinning can be selected as needed. Preferably, the conditions of needleless electrospinning include: the effective width of needleless electrospinning is 20-60 cm. In the present invention, a highly consistent high-performance and long-life COP-based nanofiber membrane can be prepared.

[0048] According to a preferred embodiment of the present invention, the conditions for needleless electrospinning include: the feeding speed of the spinning dispersion liquid is 80 - 150 ml / h.

[0049] According to a preferred embodiment of the present invention, the conditions for needleless electrospinning include: the sliding speed of the coating head is 60 - 140 mm / s.

[0050] According to a preferred embodiment of the present invention, the conditions for needleless electrospinning include: the conveyor belt speed is 0.01 - 0.05 m / min.

[0051] According to a preferred embodiment of the present invention, the conditions for needleless electrospinning include: the winding tension is 0.5 - 3 kg.

[0052] According to a preferred embodiment of the present invention, the conditions for the hydrothermal reaction include: the temperature is 60 - 200 °C, preferably 65 - 180 °C. The COP-based nanofiber membrane prepared by the foregoing embodiment has a longer lifespan and catalytic activity.

[0053] According to the present invention, as long as the object of the present invention can be achieved, the time of the hydrothermal reaction is not particularly limited. Preferably, the conditions for the hydrothermal reaction include: the time is 1 - 24 h, preferably 4 - 12 h.

[0054] According to the present invention, in order to better continuously produce the COP-based nanofiber membrane, preferably, the fiber membrane after the hydrothermal reaction enters the hydrothermal treatment by winding. Preferably, before the hydrothermal treatment, the product is simply post-treated by a conventional method in the art. The purpose of the post-treatment is to remove some unreacted raw materials (such as organic ligands) and solvents. The specific method is not limited. Preferably, the post-treatment method includes cleaning and drying; wherein, the cleaning agent used for cleaning is not particularly limited. Preferably, the cleaning agent used for cleaning is selected from at least one of pure water, ethanol, and methanol; drying can be carried out in a conventional manner in the art, for example, the drying temperature is 50 - 100 °C.

[0055] After the COP-based nanofiber membrane is prepared by the present invention, downstream products based on the COP-based nanofiber membrane can also be continuously prepared as needed. The second aspect of the present invention provides a method for continuously preparing an oxygen electrode. The preparation method includes: preparing a COP-based nanofiber membrane according to the method for preparing a COP-based nanofiber membrane described in the present invention, and then compounding the prepared COP-based nanofiber membrane with a gas diffusion layer to obtain an oxygen electrode.

[0056] In the present invention, it is possible to continuously batch-produce, with low cost, low energy consumption, high consistency, and low cost, an oxygen electrode. When the oxygen electrode is in use, the catalytic layer is not easily detached, and it exhibits excellent oxygen reduction performance and cycle stability.

[0057] According to the present invention, in order to better continuously produce oxygen electrodes, preferably, the COP-based nanofiber membrane is conveyed to a roll-to-roll roller press by rollers and laminated with the gas diffusion layer in a roll-to-roll lamination manner.

[0058] According to the present invention, the lamination strength between the nanofiber membrane and the gas diffusion layer can be controlled by changing the spacing or pressure of the rollers. Preferably, when the rollers are conveying: the diameter of the rollers is 20 - 60 cm; the spacing between the rollers is 0.1 - 0.4 mm, and the running tension is 10 - 50 N.

[0059] According to the present invention, the thickness of the gas diffusion layer is 0.10 - 0.35 mm.

[0060] In the present invention, the specific type of the gas diffusion layer is not particularly limited, and commonly used gas diffusion layers in the art are applicable. The present invention will not elaborate on this too much.

[0061] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, all raw materials can be obtained commercially.

[0062] Example 1

[0063] Preparation of electrospinning dispersion: Add 13 kg of N,N-dimethylformamide to a 50 L glass stirring kettle, and then add 1.5 kg of polymer polyvinylidene fluoride (number average molecular weight of 1 million), 0.37 kg of polyvinylpyrrolidone (nitrogen content of 12.6 wt%, number average molecular weight of 1.3 million), and 0.37 kg of carbon black (particle size of 40 nm, spherical shape) to the glass stirring kettle. Stir at 200 rpm for 10 h by ultrasonic, and then add 0.3 kg of cobalt chloride to the glass stirring kettle. Control the temperature at 30 °C, the stirring speed at 200 rpm, and the stirring time at 5 h to obtain the electrospinning dispersion;

[0064] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 1,2,4,5-tetracyanobenzene and 100 kg of solvent ethylene glycol to a 150 L glass stirring kettle and mix to obtain a transparent solution. Then, add 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene to the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0065] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment to 30°C and the humidity to 30%. After the internal environment stabilizes, transfer the prepared electrospinning dispersion to the liquid supply chamber of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed to 120 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure is 37 kV, negative pressure is -13 kV). At the same time, turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.02 m / min), the winding and unwinding device (the winding and unwinding tension is 20 N) and the deviation correction device, and wind up to obtain the nanofiber membrane precursor with an effective width of 60 cm;

[0066] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature rising program of the organic ligand material pool, and the target temperature is 180°C. When the current temperature is reached, turn on the tension rotating shaft of the needleless electrospinning equipment. The nanofiber membrane precursor (with a total surface area of about 52 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and is treated at 180°C for 4 h to obtain the nanofiber membrane loaded with the catalyst;

[0067] The nanofiber membrane loaded with the catalyst is then conveyed to a cleaning pool filled with pure water and ethanol (volume ratio 1:1) for cleaning. After being cleaned, it is conveyed to an oven and dried to obtain the COP-based nanofiber membrane (thickness is 0.15 mm);

[0068] The COP-based nanofiber membrane is conveyed by rollers (the diameter of the rollers is 60 cm, and the distance between the rollers is 0.25 mm) to a roll-to-roll roller press for lamination with the gas diffusion layer (thickness is 0.25 mm), and the running tension is 20 N, and finally the oxygen electrode is obtained.

[0069] Figure 1 This is the prepared oxygen electrode.

[0070] Example 2

[0071] Preparation of the electrospinning dispersion: Add 10 kg of N,N-dimethylformamide and 3 kg of acetone to a 50 L glass stirring kettle. Then add 1.7 kg of polyvinylidene fluoride (number average molecular weight is 1 million), 0.5 kg of polyvinylpyrrolidone (nitrogen content is 12.6 wt%, number average molecular weight is 1.3 million), and 0.5 kg of carbon black (particle size is 40 nm, shape is spherical) to the glass stirring kettle. Ultrasonic and stir at 200 rpm for 8 h. Then add 0.3 kg of metal salt ferric chloride to the glass stirring kettle, control the temperature at 30°C, the stirring speed is 200 rpm, and the stirring time is 5 h to obtain the electrospinning dispersion;

[0072] Preparation of organic ligand dispersion: 2 kg of organic ligand 1,2,4,5-tetracyanobenzene and 100 kg of solvent ethylene glycol were added to a 150 L glass stirring kettle and mixed to obtain a transparent solution. Then, 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene was added dropwise into the reaction kettle and stirred evenly to obtain the organic ligand dispersion;

[0073] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment to 30 °C and the humidity to 30%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply cavity of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed to 120 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure is 37 Kv, negative pressure is -13 Kv). At the same time, turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.02 m / min), the winding and unwinding device (the winding and unwinding tension is 20 N) and the deviation correction device, and wind up to obtain a nanofiber membrane precursor with an effective width of 60 cm;

[0074] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature rising program of the organic ligand material pool, and the target temperature is 180 °C. When the current temperature is reached, turn on the tension rotating shaft of the needleless electrospinning equipment. The nanofiber membrane precursor (with a total surface area of about 54 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and treated at 180 °C for 4 h to obtain a nanofiber membrane loaded with the catalyst;

[0075] The nanofiber membrane loaded with the catalyst is then conveyed to a cleaning pool containing pure water and ethanol (volume ratio 1:1) for cleaning. After being cleaned, it is conveyed to an oven and dried to obtain a COP-based nanofiber membrane (thickness 0.15 mm);

[0076] The COP-based nanofiber membrane is conveyed to a roll-to-roll roller press through rollers (the diameter of the rollers is 60 cm, and the distance between the rollers is 0.25 mm) and laminated with a gas diffusion layer (thickness 0.25 mm), and the running tension is 20 N to finally obtain an oxygen electrode.

[0077] Example 3

[0078] Preparation of electrospinning dispersion: Add 10 kg of N,N-dimethylformamide and 3 kg of acetone into a 50 L glass stirring kettle. Then add 1.7 kg of polystyrene (number-average molecular weight is 100,000), 1 kg of polyacrylonitrile (nitrogen content is 26.4 wt%, number-average molecular weight is 150,000), and 0.5 kg of conductive graphite (particle size is 100 nm and shape is flaky) into the glass stirring kettle. Ultrasonic and stir at 200 rpm for 8 h. Then add 0.3 kg of metal salt ferric chloride into the glass stirring kettle, control the temperature at 30 °C, the stirring speed at 200 rpm, and the stirring time at 5 h to obtain the electrospinning dispersion;

[0079] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 2,3,5,6-tetrafluoroterephthalonitrile and 100 kg of ethylene glycol into a 150 L glass stirring kettle and mix to obtain a transparent solution. Then drop 1.2 kg of 1,8-diazabicyclo[5,4,0]undec-7-ene into the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0080] Turn on the electrospinning equipment, set the internal temperature of the equipment at 35 °C and the humidity at 40%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply chamber of the electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 80 ml / h, turn on the sliding table coating head (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure is 37 kV, negative pressure is -13 kV), and at the same time turn on the conveyor belt (the conveyor belt speed is 0.03 m / min), the winding and unwinding device (the winding and unwinding tension is 20 N) and the deviation correction device, and wind up to obtain the nanofiber membrane precursor with an effective width of 60 cm;

[0081] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature rising program of the organic ligand material pool, and the target temperature is 65 °C. When reaching the current temperature, turn on the tension rotating shaft of the needleless electrospinning equipment. The nanofiber membrane precursor (total surface area is about 60 m 2 ) is conveyed to the inside of the organic ligand material pool through the tension rotating shaft and is treated at 65 °C for 12 h to obtain the nanofiber membrane loaded with the catalyst;

[0082] The nanofiber membrane loaded with the catalyst is then conveyed to a cleaning pool filled with ethanol for cleaning. After cleaning, it is conveyed to an oven for drying to obtain the COP-based nanofiber membrane (thickness is 0.12 mm);

[0083] Convey the COP-based nanofiber membrane to a roll-to-roll roller press through rollers (the diameter of the rollers is 60 cm and the distance between the rollers is 0.30 mm) to be compounded with the gas diffusion layer (thickness is 0.25 mm), and the running tension is 20 N, and finally obtain the oxygen electrode.

[0084] Example 4

[0085] Preparation of electrospinning dispersion: Add 10 kg of the solvent tetrahydrofuran into a 50 L glass stirring kettle. Then add 1.5 kg of polystyrene (number average molecular weight is 220,000), 0.4 kg of polyetherimide (nitrogen content is 4.5 wt%, number average molecular weight is 80,000), and 0.2 kg of conductive agent carbon nanotubes (particle size is 25 nm, shape is columnar) into the glass stirring kettle. Ultrasonic and stir at 200 rpm for 8 h. Then add 0.25 kg of ferric sulfate into the glass stirring kettle, control the temperature at 40 °C, the stirring speed is 200 rpm, and the stirring time is 5 h to obtain the electrospinning dispersion;

[0086] Preparation of organic ligand dispersion: Add 0.8 kg of organic ligand 2,3,6,7,10,11 - hexaaminotriphenyl hexahydrochloride and 100 kg of solvent pure water into a 150 L glass stirring kettle and mix to obtain a transparent solution. Then add 30 kg of reaction catalyst sodium acetate into the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0087] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment at 35 °C and the humidity at 45%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply cavity of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 150 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high - pressure stainless - steel wire, turn on the high voltage (positive pressure is 30 Kv, negative pressure is - 10 Kv). At the same time, turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.05 m / min), the winding and unwinding device (the winding and unwinding tension is 2 kg) and the deviation correction device, and wind up to obtain the nanofiber membrane precursor with an effective width of 60 cm;

[0088] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature - rising program of the organic ligand material pool, the target temperature is 65 °C. When reaching the current temperature, turn on the tension rotating shaft. The nanofiber membrane precursor (total surface area is about 56 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and is treated at 65 °C for 12 h to obtain the nanofiber membrane loaded with the catalyst;

[0089] The nanofiber membrane loaded with the catalyst is then conveyed to a cleaning pool filled with pure water for cleaning. After being cleaned, it is conveyed to an oven for drying to obtain the COP - based nanofiber membrane (thickness is 0.1 mm);

[0090] Convey the COP - based nanofiber membrane through rollers (the diameter of the rollers is 60 cm, the distance between the rollers is 0.30 mm) to a roll - to - roll roller press for lamination with a gas diffusion layer (thickness is 0.25 mm), and the running tension is 20 N to finally obtain the oxygen electrode.

[0091] Example 5

[0092] Preparation of electrospinning dispersion: Add 10 kg of N,N-dimethylformamide and 3 kg of acetone into a 50 L glass stirring kettle. Then add 1 kg of polyacrylonitrile (nitrogen content 26.4 wt%, number average molecular weight 150,000) and 1.75 kg of conductive graphite (particle size 100 nm, shape flaky) into the glass stirring kettle. Ultrasonic and stir at 200 rpm for 8 h. Then add 0.3 kg of metal salt ferric chloride into the glass stirring kettle, control the temperature at 30 °C, the stirring speed at 200 rpm, and the stirring time at 5 h to obtain the electrospinning dispersion;

[0093] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 2,3,5,6-tetrafluoroterephthalonitrile and 100 kg of solvent ethylene glycol into a 150 L glass stirring kettle to mix and obtain a transparent solution. Then add 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene dropwise into the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0094] Turn on the electrospinning equipment, set the internal temperature of the equipment at 35 °C and the humidity at 40%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply chamber of the electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 80 ml / h, turn on the slide coating head (coating head sliding speed 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure 37 kV, negative pressure -13 kV), and at the same time turn on the conveyor belt (conveyor belt speed 0.03 m / min), the winding and unwinding reel (winding and unwinding reel tension 20 N) and the deviation correction device, and wind up to obtain a nanofiber membrane precursor with an effective width of 60 cm;

[0095] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature increase program of the organic ligand material pool, the target temperature is 65 °C. When reaching the current temperature, turn on the tension rotating shaft of the needleless electrospinning equipment, and the nanofiber membrane precursor (total surface area about 60 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and treated at 65 °C for 12 h to obtain a nanofiber membrane loaded with the catalyst;

[0096] The nanofiber membrane loaded with the catalyst is then conveyed to a cleaning pool filled with ethanol for cleaning, and after being cleaned, it is conveyed to an oven for drying to obtain a COP-based nanofiber membrane (thickness 0.15 mm);

[0097] Convey the COP-based nanofiber membrane through rollers (roller diameter 60 cm, roller spacing 0.30 mm) to a roll-to-roll roller press for lamination with a gas diffusion layer (thickness 0.25 mm), and the running tension is 20 N, and finally an oxygen electrode is obtained.

[0098] Example 6

[0099] Preparation of electrospinning dispersion: Add 13 kg of N,N-dimethylformamide into a 50 L glass stirring kettle. Then add 1.5 kg of polyvinylidene fluoride (number-average molecular weight of 1 million), 0.37 kg of polyvinylpyrrolidone (nitrogen content of 12.6 wt%, number-average molecular weight of 1.3 million), and 0.37 kg of conductive copper powder (particle size of 400 nm, spherical shape) into the glass stirring kettle. Stir for 10 h by ultrasonic wave at 200 rpm. Then add 0.3 kg of cobalt chloride into the glass stirring kettle, control the temperature at 30 °C, the stirring speed at 200 rpm, and the stirring time at 5 h to obtain the electrospinning dispersion;

[0100] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 1,2,4,5-tetracyanobenzene and 100 kg of solvent ethylene glycol into a 150 L glass stirring kettle and mix to obtain a transparent solution. Then add 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene into the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0101] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment at 30 °C and the humidity at 30%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply cavity of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 120 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure is 37 Kv, negative pressure is -13 Kv), and at the same time turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.02 m / min), the winding and unwinding device (the winding and unwinding tension is 20 N) and the deviation correction device to obtain a nanofiber membrane precursor with an effective width of 60 cm;

[0102] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the heating program of the organic ligand material pool, and the target temperature is 180 °C. When the current temperature is reached, turn on the tension rotating shaft of the needleless electrospinning equipment, and the nanofiber membrane precursor (total surface area is about 52 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and treated at 180 °C for 4 h to obtain a nanofiber membrane loaded with catalyst;

[0103] The nanofiber membrane loaded with catalyst is then conveyed to a cleaning tank filled with pure water and ethanol (volume ratio of 1:1) for cleaning. After being cleaned, it is conveyed to an oven and dried to obtain a COP-based nanofiber membrane (thickness is 0.15 mm);

[0104] The COP-based nanofiber membrane is conveyed by a roller (the diameter of the roller is 60 cm, and the distance between the rollers is 0.25 mm) to a roll-to-roll press for lamination with a gas diffusion layer (thickness 0.25 mm), with an operating tension of 20 N, and finally an oxygen electrode is obtained.

[0105] Example 7

[0106] Preparation of electrospinning dispersion: Add 13 kg of N,N-dimethylformamide to a 50 L glass stirring kettle, and then add 1.87 kg of polyvinylidene fluoride (number-average molecular weight of 1 million) and 0.37 kg of carbon black (particle size of 40 nm, spherical shape) to the glass stirring kettle. Stir for 10 h under ultrasonic and at 200 rpm, and then add 0.3 kg of cobalt chloride to the glass stirring kettle. Control the temperature at 30 °C, with a stirring speed of 200 rpm and a stirring time of 5 h to obtain the electrospinning dispersion;

[0107] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 1,2,4,5-tetracyanobenzene and 100 kg of solvent ethylene glycol to a 150 L glass stirring kettle and mix to obtain a transparent solution. Then, add 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene to the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0108] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment at 30 °C and the humidity at 30%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply chamber of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 120 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure is 37 Kv, negative pressure is -13 Kv), and at the same time turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.02 m / min), the winding and unwinding device (the winding and unwinding tension is 20 N) and the deviation correction device. A nanofiber membrane precursor is obtained by winding, with an effective width of 60 cm;

[0109] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the temperature increase program of the organic ligand material pool, with the target temperature of 180 °C. When the current temperature is reached, turn on the tension rotating shaft of the needleless electrospinning equipment. The nanofiber membrane precursor (total surface area is about 54 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and is treated at 180 °C for 4 h to obtain a nanofiber membrane loaded with a catalyst;

[0110] The nanofiber membrane loaded with a catalyst is then conveyed to a cleaning pool filled with pure water and ethanol (volume ratio 1:1) for cleaning. After being cleaned, it is conveyed to an oven for drying to obtain a COP-based nanofiber membrane (thickness 0.15 mm);

[0111] The COP-based nanofiber membrane is conveyed by a roller (the diameter of the roller is 60 cm and the spacing between the rollers is 0.25 mm) to a roll-to-roll roller press for lamination with a gas diffusion layer (thickness 0.25 mm), with an operating tension of 20 N, and finally an oxygen electrode is obtained.

[0112] Example 8

[0113] Preparation of electrospinning dispersion: Add 13 kg of N,N-dimethylformamide to a 50 L glass stirring kettle, and then add 1.5 kg of polymer polyvinylidene fluoride (number average molecular weight of 1 million), 0.37 kg of polyvinylpyrrolidone (nitrogen content 12.6 wt%, number average molecular weight of 1.3 million), and 0.37 kg of carbon black (particle size 40 nm, spherical shape) to the glass stirring kettle. Stir for 10 h by ultrasonic and at 200 rpm, and then add 0.35 kg of cobalt chloride hexahydrate to the glass stirring kettle. Control the temperature at 30 °C, the stirring speed at 200 rpm, and the stirring time at 5 h to obtain the electrospinning dispersion;

[0114] Preparation of organic ligand dispersion: Add 2 kg of organic ligand 1,2,4,5-tetracyanobenzene and 100 kg of solvent ethylene glycol to a 150 L glass stirring kettle and mix to obtain a transparent solution. Then, add 1.2 kg of hydrothermal reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene to the reaction kettle and stir evenly to obtain the organic ligand dispersion;

[0115] Turn on the needleless electrospinning equipment, set the internal temperature of the equipment at 30 °C and the humidity at 30%. After the internal environment is stable, transfer the prepared electrospinning dispersion to the liquid supply chamber of the needleless electrospinning equipment. Turn on the liquid supply pump, set the liquid supply speed at 120 ml / h, turn on the sliding table coating head of the needleless electrospinning equipment (the sliding speed of the coating head is 100 mm / s). When the spinning solution evenly covers the high-pressure stainless steel wire, turn on the high voltage (positive pressure 37 Kv, negative pressure -13 Kv), and at the same time turn on the conveyor belt of the needleless electrospinning equipment (the conveyor belt speed is 0.02 m / min), the winding and unwinding (the winding and unwinding tension is 20 N) and the deviation correction device, and wind up to obtain a nanofiber membrane precursor with an effective width of 60 cm;

[0116] Put the prepared organic ligand dispersion into the organic ligand material pool, turn on the heating program of the organic ligand material pool, and the target temperature is 180 °C. When the current temperature is reached, turn on the tension rotating shaft of the needleless electrospinning equipment. The nanofiber membrane precursor (total surface area about 52 m 2 ) is conveyed into the organic ligand material pool through the tension rotating shaft and treated at 180 °C for 4 h to obtain a nanofiber membrane loaded with the catalyst;

[0117] The catalyst-loaded nanofiber membrane was then transferred to a cleaning tank containing pure water and ethanol (volume ratio 1:1) for cleaning. After being cleaned, it was transferred to an oven for drying to obtain a COP-based nanofiber membrane (thickness 0.10 mm).

[0118] The COP-based nanofiber membrane was transferred by rollers (roller diameter 60 cm, roller spacing 0.25 mm) to a roll-to-roll roller press for lamination with a gas diffusion layer (thickness 0.25 mm). The operating tension was 20 N, and finally an oxygen electrode was obtained.

[0119] Comparative Example 1

[0120] Preparation of COP catalyst:

[0121] ① 2 kg of the organic ligand 1,2,4,5-tetracyanobenzene was dispersed in 100 kg of the solvent ethylene glycol. 2 kg of the metal salt cobalt chloride was added and dissolved by ultrasound to obtain a transparent solution. 0.6 kg of the reaction catalyst 1,8-diazabicyclo[5,4,0]undec-7-ene was added and stirred evenly to obtain a catalytic reaction feed solution.

[0122] ② The obtained catalytic reaction feed solution was placed in a reaction kettle.

[0123] ③ The reaction kettle was placed in a vacuum drying oven, the temperature was set at 180 °C, and the reaction continued for 4 h.

[0124] The precipitate obtained from the reaction was taken out of the reaction kettle and washed successively with dilute hydrochloric acid, deionized water and ethanol, and then placed in an oven at 60 °C for drying to obtain the COP catalyst.

[0125] Preparation of oxygen electrode:

[0126] 500 g of the prepared COP catalyst powder was weighed and added to a mixed solution of 10 L of ultrapure water and 90 L of ethanol. The above mixture was ultrasonically dispersed in an ultrasonic wave to ensure the uniformity in all directions of the slurry. Finally, 2.500 L of 5% Nafion solution was added and ultrasonically homogenized to be used as catalyst ink. The catalyst ink was uniformly loaded onto the hydrophobic gas diffusion layer by spraying to obtain the oxygen electrode.

[0127] Performance test

[0128] (1) Sample preparation

[0129] The oxygen electrodes prepared in the examples were respectively cut into samples with a size of 1*1 cm.

[0130] (2) Preparation of electrolyte solution

[0131] A 7M KOH + 0.2 ZnO electrolyte aqueous solution was prepared using a 500 ml volumetric flask.

[0132] (3) Preparation of electrodes

[0133] The negative electrode uses a polished zinc foil with a thickness of 0.5 mm; the air positive electrode uses the above sample.

[0134] (4) Battery performance test

[0135] A rechargeable zinc-air flow battery is assembled with a polished zinc foil with a thickness of 0.5 mm, an oxygen electrode, an electrolyte, and a circulating peristaltic pump. The power density curve and charge-discharge curve are tested using a Wuhan Blue Electric CT3002A test system. The specific steps are as follows: In the discharge mode, a current that increases regularly from 0 mA is applied to the battery, increasing by 5 mA every 10 seconds, to obtain a curve of voltage versus current density. The power density curve is obtained by multiplying the current density by the voltage. The current density is set to 20 mA cm -2 , the charging time is set to 30 min, and the discharging time is set to 30 min to obtain a curve of voltage versus time.

[0136] Space-time yield test: It is obtained by calculating the quantity of the target product obtained by a unit volume of the device per unit time.

[0137] Power density test: It is obtained by multiplying the current density in the polarization curve measured by the Blue Electric test system by the corresponding voltage.

[0138] Overpotential test: It is obtained by subtracting the discharge voltage from the charging voltage measured by the Blue Electric test system.

[0139] Figure 2 The charge-discharge cycle diagram of the battery assembled with the oxygen electrode of the example is from Figure 2 It can be obtained that the oxygen electrode prepared in batch by the present invention has excellent cycle stability and reduced overpotential.

[0140] The results are shown in Table 1

[0141]

[0142] From the results in Table 1, it can be seen that the preparation method of the present invention has a high space-time yield, and the oxygen electrode has a high power density and a low overpotential at the same time, with significantly better effects.

[0143] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for continuously preparing a COP-based nanofiber membrane, characterized in that: The preparation method comprises: (1) subjecting a spinning dispersion containing a high molecular weight polymer, a metal source and a conductive agent to needle-free electrospinning; (2) In the presence of a hydrothermal reaction catalyst, the fiber membrane obtained by needle-free electrospinning is hydrothermally treated with an organic ligand dispersion containing an organic ligand, and then post-treated to obtain a COP-based nanofiber membrane.

2. The method according to claim 1, wherein: The content of water-soluble polymer in the polymer is not higher than 50wt%, preferably 0-40wt%; and / or The high molecular polymer is selected from nitrogen-containing high molecular polymers and / or non-nitrogen-containing high molecular polymers; and / or The number average molecular weight of the high molecular weight polymer is 60,000-1.5 million; Preferably, The polymer is selected from nitrogen-containing polymers and non-nitrogen-containing polymers, and preferably the mass ratio of the nitrogen-containing polymer to the non-nitrogen-containing polymer is 1:(1-6); and / or The nitrogen-containing high molecular polymer is selected from at least one of polyurethane, polyacrylonitrile, polyimide, polyvinyl pyrrolidone, polyethylene imine and polyether imide, preferably at least one of polyacrylonitrile, polyimide, polyvinyl pyrrolidone, polyethylene imine and polyether imide; and / or The nitrogen content of the nitrogen-containing high molecular polymer is 10wt%-30wt%; and / or The non-nitrogen-containing high molecular polymer is selected from at least one of polytetrafluoroethylene, polychlorodifluoroethylene, polyvinylidene fluoride, polystyrene, polyvinyl alcohol, polyethylene oxide and polyacrylic acid.

3. The method according to claim 1 or 2, wherein The metal source is selected from inorganic metal salts corresponding to the transition metals, and preferably the inorganic metal salt is an inorganic metal salt without crystal water; Preferably, the transition metal is selected from at least one of iron, cobalt, manganese, nickel and copper; and / or The conductive agent is selected from at least one of carbon black, carbon nanotubes, polyaniline, graphite, graphene and copper powder, preferably at least one of carbon black, graphite and graphene; and / or The conductive agent is in at least one of a spherical, flake, columnar and lamellar shape, preferably a spherical and / or flake shape; and / or The particle size of the conductive agent is 10-300 nm, preferably 20-120 nm.

4. The method according to any one of claims 1 to 3, wherein: The hydrothermal reaction catalyst is selected from compounds that can promote the Schiff base polymerization of organic ligands to form a COP configuration, preferably selected from at least one of sodium acetate, 1,8-diazacyclo[5,4,0]undecene-7, 2,2-dimethyl-1,3-dioxep-5-ene and 1,4,7-triazacyclononane, preferably at least one of 1,8-diazacyclo[5,4,0]undecene-7, 2,2-dimethyl-1,3-dioxep-5-ene and 1,4,7-triazacyclononane; and / or The organic ligand contains nitrogen, preferably one or more selected from 2,3,6,7,10,11-hexaaminotriphenyl hexahydrochloride, 1,2-dicyanobenzene, 1,3,5-tris(4-aminophenyl)benzene, 3,5-diphenylbiphenyl-4-amine, 1,2,4,5-tetracyanobenzene, 2,3,5,6-tetrafluoroterephthalonitrile and 3,4,5,6-tetrafluorophthalonitrile; and / or The solvent in the spinning dispersion is selected from at least one of acetone, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene dichloride, dichloromethane and tetrahydrofuran; and / or The solvent in the organic ligand dispersion is selected from at least one of N,N-dimethylformamide, ethylene glycol, ethanol, methanol, triethanolamine, ether, water and chloroform.

5. The method according to any one of claims 1 to 4, wherein: The thickness of the fiber membrane is 0.01-0.5 mm, preferably 0.1-0.3 mm; and / or The content of the hydrothermal reaction catalyst in the organic ligand dispersion is 0.5-30wt%, preferably 0.5-3wt%; and / or In the organic ligand dispersion, the content of organic ligand is 0.5-8wt%, preferably 1.5-5wt%; and / or In the spinning dispersion, the content of the high molecular weight polymer is 5-50wt%, preferably 10-30wt%; and / or Based on the total mass of polymer, metal source and conductive agent: The content of the high molecular weight polymer is 55-90wt%, preferably 65-85wt%; and / or The content of the metal source is 1-25wt%, 5-20wt%; and / or The content of the conductive agent is 1-25wt%, 5-20wt%; and / or The total surface area of ​​the fiber membrane is x, cm 2 , the volume of the organic ligand dispersion is y, ml, then x:y=(0.1-10):

1.

6. The method according to any one of claims 1 to 5, wherein: The conditions of the needle-free electrospinning include: Temperature of 20-38°C; and / or Humidity of 25-35%; and / or Positive voltage of 15-45 kV; and / or Negative pressure of -15 to -5 kV; and / or The effective width of needle-free electrospinning is 20-60 cm; and / or The feeding speed of the spinning dispersion is 80-150 ml / h; and / or The coating head sliding speed is 60-140mm / s; and / or Conveyor belt speed is 0.01-0.05m / min; and / or The rewinding and unwinding tension is 5-30N.

7. The method according to any one of claims 1 to 6, wherein: The conditions of the hydrothermal treatment include: a temperature of 60-200° C., preferably 65-180° C.; and / or a time of 1-24 h, preferably 4-12 h; and / or The fiber membrane after the hydrothermal reaction enters the post-processing step by winding; and / or The post-treatment method includes cleaning and drying; Preferably, The cleaning agent used for cleaning is selected from at least one of pure water, ethanol and methanol; and / or The drying temperature is 50-100°C.

8. A method for continuously preparing an oxygen electrode, characterized in that: The preparation method comprises: A COP-based nanofiber membrane is prepared according to the method described in any one of claims 1 to 7, and then the prepared COP-based nanofiber membrane is compounded with a gas diffusion layer to obtain an oxygen electrode.

9. The method according to claim 8, wherein: The COP-based nanofiber membrane is transferred to a roll-to-roll press by a roller and composited with the gas diffusion layer by roll-to-roll lamination; and / or The thickness of the gas diffusion layer is 0.10-0.35 mm.

10. The method according to claim 9, wherein: When roller conveyor: The diameter of the roller is 20-60 cm; and / or The roller spacing is 0.1-0.4 mm; and / or The operating tension is 10-50N.

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