阅读说明：本技术 一种电池隔膜用材料、材料制备方法及电池隔膜 (Material for battery diaphragm, material preparation method and battery diaphragm ) 是由 叶家业 郑春花 李慧云 张翼滉 刘艳琳 于 2021-05-19 设计创作，主要内容包括：本申请公开了一种电池隔膜用材料、材料制备方法及电池隔膜。电池隔膜用材料中包括碳化硅纳米线和全氟磺酸,其中,所述碳化硅纳米线和所述全氟磺酸的质量比为1:5～1:200。由于碳化硅纳米线自身具有分散性高、亲水性好等优点,同时功能化后的碳化硅纳米线表面含有磺酸基、羟基等活性基团、质子传导性高,能够在分子尺度上对质子传递通道尺寸进行调控,从而在实现质子快速传导的同时,还能够对体积相对较大的钒离子和其他金属离子的传导进行阻隔,进而提高电池的使用寿命。(The application discloses a material for a battery diaphragm, a preparation method of the material and the battery diaphragm. The material for the battery diaphragm comprises a silicon carbide nanowire and perfluorosulfonic acid, wherein the mass ratio of the silicon carbide nanowire to the perfluorosulfonic acid is 1: 5-1: 200. The silicon carbide nanowire has the advantages of high dispersibility, good hydrophilicity and the like, and meanwhile, the functionalized silicon carbide nanowire surface contains active groups such as sulfonic groups and hydroxyl groups, the proton conductivity is high, and the size of a proton transfer channel can be regulated and controlled on a molecular scale, so that the proton can be rapidly conducted, the conduction of vanadium ions with relatively large volume and other metal ions can be blocked, and the service life of the battery can be prolonged.)

1. The material for the battery diaphragm is characterized by comprising a silicon carbide nanowire and perfluorosulfonic acid, wherein the mass ratio of the silicon carbide nanowire to the perfluorosulfonic acid is 1: 5-1: 200.

2. The material according to claim 1, wherein the silicon carbide nanowires specifically comprise: and (3) functionalizing the silicon carbide nanowire by using a sulfuric acid solution and an alcohol mixed solution.

3. The material of claim 2, wherein the concentration of the sulfuric acid solution is 0.5mol/L to 1.5 mol/L; and the number of the first and second groups,

the alcohol is methanol, ethanol or n-propanol.

4. The material of claim 1, wherein the silicon carbide nanowires have a diameter in the range of 100nm to 800 nm; and the number of the first and second groups,

the length-diameter ratio ranges from 20 to 150.

5. The material of claim 1, wherein the material is prepared by dispersing the silicon carbide nanowires in a perfluorosulfonic acid solution.

6. A battery separator, comprising: the reinforced layer and the isolation layer arranged on at least one surface of the reinforced layer, wherein the isolation layer is prepared by the material as claimed in any one of claims 1 to 4.

7. The battery separator of claim 6, wherein the battery separator is applied to a vanadium battery.

8. The battery separator as claimed in claim 6, wherein the reinforcement layer is in particular a polytetrafluoroethylene layer.

9. A method of preparing a material, comprising:

dissolving perfluorosulfonic acid resin in a mixed solution to obtain a perfluorosulfonic acid solution, wherein the mixed solution is prepared from water and propanol in a volume ratio of 1: 1;

and dispersing the silicon carbide nanowires in the perfluorinated sulfonic acid solution, wherein the mass of the silicon carbide nanowires is 0.005-0.2 times of that of the perfluorinated sulfonic acid in the perfluorinated sulfonic acid solution.

10. The method of manufacturing of claim 9, further comprising, prior to dispersing the silicon carbide nanowires in the perfluorosulfonic acid solution:

adding a high-boiling-point organic solvent into the perfluorosulfonic acid solution, wherein the mass ratio of the added high-boiling-point organic solvent to the perfluorosulfonic acid solution is 1: 5-1: 50; then the process of the first step is carried out,

dispersing the silicon carbide nanowires in the perfluorinated sulfonic acid solution, and specifically comprises the following steps:

dispersing the silicon carbide nanowires in a perfluorinated sulfonic acid solution added with a high-boiling-point organic solvent.

Technical Field

The application relates to the technical field of materials, in particular to a material for a battery diaphragm, a material preparation method and the battery diaphragm.

Background

With the continuous development of science and technology, more and more devices need to be powered by batteries, so that higher requirements are put on the service life of the batteries and the like. In the battery, the performance of the diaphragm material has a large influence on the service life of the battery, for example, in the current vanadium battery, the service life of the vanadium battery is short because the barrier capability of the diaphragm material to vanadium ions is relatively poor.

Disclosure of Invention

The embodiment of the application provides a material for a battery diaphragm, a material preparation method and the battery diaphragm, which are used for solving the problems in the prior art.

The embodiment of the application provides a material for a battery diaphragm, the material comprises a silicon carbide nanowire and perfluorosulfonic acid, wherein the mass ratio of the silicon carbide nanowire to the perfluorosulfonic acid is 1: 5-1: 200.

Preferably, the silicon carbide nanowires specifically include: and (3) functionalizing the silicon carbide nanowire by using a sulfuric acid solution and an alcohol mixed solution.

Preferably, the concentration of the sulfuric acid solution is 0.5-1.5 mol/L; and the number of the first and second groups,

the alcohol is methanol, ethanol or n-propanol.

Preferably, the diameter range of the silicon carbide nanowire is 100 nm-800 nm; and the length-diameter ratio ranges from 20 to 150.

Preferably, the material is prepared by dispersing the silicon carbide nanowires in a perfluorosulfonic acid solution.

An embodiment of the present application further provides a battery separator, including: the reinforced layer comprises a reinforced layer and an isolation layer arranged on at least one surface of the reinforced layer, wherein the isolation layer is prepared by using the material provided by the embodiment of the application.

Preferably, the battery diaphragm is applied to a vanadium battery.

Preferably, the reinforcing layer is a polytetrafluoroethylene layer.

The embodiment of the application also provides a preparation method of the material, which comprises the following steps:

dissolving perfluorosulfonic acid resin in a mixed solution to obtain a perfluorosulfonic acid solution, wherein the mixed solution is prepared from water and propanol in a volume ratio of 1: 1;

and dispersing the silicon carbide nanowires in the perfluorinated sulfonic acid solution, wherein the mass of the silicon carbide nanowires is 0.005-0.2 times of that of the perfluorinated sulfonic acid in the perfluorinated sulfonic acid solution.

Preferably, before the silicon carbide nanowires are dispersed in the perfluorosulfonic acid solution, the preparation method further comprises: adding a high-boiling-point organic solvent into the perfluorosulfonic acid solution, wherein the mass ratio of the added high-boiling-point organic solvent to the perfluorosulfonic acid solution is 1: 5-1: 50; then the process of the first step is carried out,

dispersing the silicon carbide nanowires in the perfluorinated sulfonic acid solution, and specifically comprises the following steps:

dispersing the silicon carbide nanowires in a perfluorinated sulfonic acid solution added with a high-boiling-point organic solvent.

The embodiment of the application adopts at least one technical scheme which can achieve the following beneficial effects:

by adopting the material provided by the embodiment of the application, the material comprises the silicon carbide nanowires and the perfluorosulfonic acid, and the mass ratio of the silicon carbide nanowires to the perfluorosulfonic acid is 1: 5-1: 200. The silicon carbide nanowires have the advantages of high dispersibility, good hydrophilicity, high proton conductivity and the like, and meanwhile, the functionalized silicon carbide nanowires contain active groups such as sulfonic groups and hydroxyl groups on the surfaces and can regulate and control the size of a proton transfer channel on a molecular scale, so that the quick proton transfer is realized, the conduction of vanadium ions and other metal ions with relatively large volume can be blocked, and the service life of the battery is prolonged. In addition, the ion selectivity of the diaphragm is greatly improved through the rapid conduction of protons and the obstruction of vanadium ions and other metal ions.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic flow chart of a material preparation method provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a specific structure of a battery separator according to an embodiment of the present disclosure;

fig. 3 is a graph comparing the performance test results of a vanadium battery using the battery separator provided in the embodiment of the present application with those of a vanadium battery of the prior art.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical solutions provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

As shown above, the performance of the separator material in the battery has a large influence on the service life of the battery, for example, in the current vanadium battery, the service life of the vanadium battery is short due to the relatively poor barrier capability of the separator material to vanadium ions.

Based on this, the embodiment of the application provides a material for a battery diaphragm, which can be applied to a battery diaphragm of a battery, such as a battery diaphragm of a vanadium battery, so that the blocking capability of the battery diaphragm of the vanadium battery on vanadium ions is improved, and the service life of the battery is further prolonged.

The material for the battery diaphragm comprises a silicon carbide nanowire and perfluorosulfonic acid, and the mass ratio of the silicon carbide nanowire to the perfluorosulfonic acid is 1: 5-1: 200. For example, in the material, the mass ratio between the silicon carbide nanowires and the perfluorosulfonic acid is 1:5, 1:7, 1:10, 1:15, 1:20, 1:25, 1:30, 1:40, 1:47, 1:50, 1:60, 1:65, 1:70, 1:75, 1:80, 1:88, 1:92, 1:98, 1:100, 1:110, 1:130, 1:170, 1:200, or other values between 1:5 and 1: 200. In addition, the mass ratio of the silicon carbide nanowires to the perfluorosulfonic acid may be more preferably 1:10 to 1:100, such as 1:10, 1:20, 1:40, 1:80, 1:100, or other values between 1:10 and 1: 100.

By adopting the material provided by the embodiment of the application, the material comprises the silicon carbide nanowires and the perfluorosulfonic acid, and the mass ratio of the silicon carbide nanowires to the perfluorosulfonic acid is 1: 5-1: 200. The silicon carbide nanowire has the advantages of high dispersibility, good hydrophilicity and the like, and meanwhile, the functionalized silicon carbide nanowire surface contains active groups such as sulfonic groups and hydroxyl groups, the proton conductivity is high, the size of a proton transfer channel can be regulated and controlled on a molecular scale, so that the proton quick conduction is realized, the conduction of vanadium ions and other metal ions with relatively large volume (relative to the volume of protons) can be blocked, and the service life of the battery is further prolonged. In addition, the ion selectivity of the diaphragm is greatly improved through the rapid conduction of protons and the obstruction of vanadium ions and other metal ions.

It should be noted that the silicon carbide nano-grade can be a non-porous or a small-porous silicon carbide nano-grade with a diameter range of 100nm to 800nm and a length-diameter ratio of 20 to 150, so as to obtain a better technical effect.

In addition, the silicon carbide nanowire can regulate and control the size of a proton transfer channel on a molecular scale, so that in order to further improve the performance of the material, the silicon carbide nanowire can be functionalized, and active groups such as sulfonic groups, hydroxyl groups and the like are introduced to the surface of the silicon carbide nanowire.

For example, the silicon carbide nanowire may be functionalized by using an alcoholic solution of sulfuric acid, specifically, the unfunctionalized silicon carbide nanowire may be put into a mixed solution of a sulfuric acid solution and an alcohol, and then a reflux reaction is performed, so as to functionalize the silicon carbide nanowire, for example, a sulfonic acid group is introduced on the surface of the silicon carbide nanowire. In the mixed solution of the sulfuric acid solution and the alcohol, the alcohol may be low-boiling-point alcohol such as methanol, ethanol or n-propanol, and the concentration of sulfuric acid in the mixed solution of the sulfuric acid solution and the alcohol is 0.5mol/L to 1.5mol/L, such as 0.5mol/L, 1mol/L, 1.5mol/L or other concentrations between 0.5mol/L and 1.5 mol/L.

For example, a 1mol/L sulfuric acid solution may be prepared and mixed with ethanol, and then the unfunctionalized silicon carbide nanowires may be put into the sulfuric acid solution and ethanol mixed solution, and then a reflux reaction may be performed to functionalize the silicon carbide nanowires.

When the unfunctionalized silicon carbide nanowires are put into the mixed solution of the sulfuric acid solution and the alcohol, the mass of the unfunctionalized silicon carbide nanowires to be put into the mixed solution of the sulfuric acid solution and the alcohol can be determined by combining the volumes of the mixed solution of the sulfuric acid solution and the alcohol, and for example, the mass (in g) is 0.01 to 0.025 times (in g/mL, that is, g per mL) the volume (in mL) of the mixed solution of the sulfuric acid solution and the alcohol, and can be 0.01, 0.015, 0.02, 0.025 times, or the like. For example, when the volume of the mixed solution of the sulfuric acid solution and the alcohol is 500mL, and the mass of the unfunctionalized silicon carbide nanowires charged is 0.02 times the volume of the mixed solution of the sulfuric acid solution and the alcohol, 10g of the unfunctionalized silicon carbide nanowires are charged into the mixed solution of the sulfuric acid solution and the alcohol.

During the reflux reaction, the reaction temperature may be determined according to the boiling point of the selected solvent, and generally needs to be higher than the boiling point of the alcohol, for example, in the case of methanol, the reaction temperature may be 100 to 120 degrees celsius, such as 110 degrees celsius; when the solvent is ethanol or n-propanol, the reaction dimension may be increased as appropriate, for example, from 100 degrees celsius to 130 degrees celsius, considering that the boiling points of ethanol and n-propanol are higher than that of methanol.

The above is a specific introduction to the material provided in the embodiments of the present application, and a method for preparing a material, which can be used to prepare the material by dispersing silicon carbide nanowires in a perfluorosulfonic acid solution, is further provided below, and as shown in fig. 1, a specific flow diagram of the preparation method includes the following steps:

step S101: dissolving perfluorosulfonic acid resin in a mixed solution to obtain a perfluorosulfonic acid solution, wherein the mixed solution is prepared from water and propanol in a volume ratio of 1: 1.

The mixture may be prepared by first using water and propanol (1: 1 by volume), wherein the propanol may be n-propanol or isopropanol. After preparing the mixed solution, the perfluorosulfonic acid resin may be added to the mixed solution, wherein the mass (in g) of the added perfluorosulfonic acid resin may be 0.01 to 0.1 times, for example, 0.01 times, 0.05 times, 0.1 times or other values of the volume (in mL) of the mixed solution. For example, if the volume of the mixed solution is 1000mL and the mass of the perfluorosulfonic acid resin to be charged is 0.05 times the volume of the mixed solution, the mass of the perfluorosulfonic acid resin to be charged into the mixed solution is 50 g.

After the perfluorosulfonic acid resin is added to the mixed solution, in order to accelerate the dissolution rate of the perfluorosulfonic acid resin in the mixed solution, the mixed solution may be transferred to a reaction kettle, and the reaction kettle is placed in an environment of 150-250 ℃ (for example, 200 ℃, 180 ℃ and the like) for reaction, for example, for about 6 hours; and cooling to room temperature after the reaction is finished, and obtaining a clear solution which is a perfluorosulfonic acid solution.

Step S102: dispersing the silicon carbide nanowires in a perfluorinated sulfonic acid solution, wherein the mass of the silicon carbide nanowires is 0.005-0.2 times of that of the perfluorinated sulfonic acid in the perfluorinated sulfonic acid solution.

After the perfluorosulfonic acid solution is prepared in step S102, the silicon carbide nanowire may be directly added to the perfluorosulfonic acid solution, wherein the mass of the added silicon carbide nanowire is 0.005 to 0.2 times (for example, 0.005 times, 0.05 times, 0.1 times, 0.15 times, 0.2 times, etc.) of the mass of the perfluorosulfonic acid in the perfluorosulfonic acid solution, and the mass of the perfluorosulfonic acid in the perfluorosulfonic acid solution may be calculated according to the mass of the perfluorosulfonic acid resin.

After the silicon carbide nanowires are added into the perfluorinated sulfonic acid solution, the suspension can be subjected to ultrasonic oscillation or other modes to disperse the silicon carbide nanowires into the perfluorinated sulfonic acid solution. For example, the suspension is stirred for 30 minutes and then ultrasonically shaken for 3 minutes, so that the silicon carbide nanowires are dispersed in the perfluorosulfonic acid solution.

In step S101, after the perfluorosulfonic acid solution is prepared, a high-boiling organic solvent may be added to the perfluorosulfonic acid solution, wherein the mass ratio of the added high-boiling organic solvent to the perfluorosulfonic acid solution is 1: 5-1: 50; after adding the high-boiling organic solvent, dispersing the silicon carbide nanowires in the perfluorosulfonic acid solution added with the high-boiling organic solvent.

Since the mixed solution is prepared from water and propanol, the water and the propanol are easy to volatilize, and pores are easy to form in the diaphragm when the battery diaphragm is manufactured by using the material. Therefore, in the step, the organic solvent with high boiling point is added, so that the volatilization of the solvent can be slowed down, the generation of pores in the battery diaphragm is inhibited, the molecular chain rearrangement of the polymer is more sufficient in the process of drying the battery diaphragm, the internal stress of the battery diaphragm is reduced, the mechanical stability of the battery diaphragm is enhanced, and the more compact battery diaphragm is obtained.

The high-boiling organic solvent may be any of N, N-dimethylformamide, dimethyl sulfoxide, N-dimethylacetamide and N-methylpyrrolidone. For example, N-dimethylformamide may be added to the mixed solution in which the perfluorosulfonic acid resin is dissolved, and the mass of the added N, N-dimethylformamide may be 1/5 to 1/50 of the mass of the mixed solution in which the perfluorosulfonic acid resin is dissolved, and may be 1/5, 1/8, 1/10, 1/15, 1/20, 1/25, 1/30, 1/40, 1/45, 1/50, or another value.

After the high boiling point organic solvent is added to the perfluorosulfonic acid solution, the solution may be mixed uniformly by stirring, shaking, or the like.

After the material provided by the embodiment of the application is prepared by the material preparation method, the material can be applied to a battery separator, so that the embodiment of the application can also provide a battery separator. As shown in fig. 2, the battery separator 20 includes a reinforcing layer 21 and a separating layer 22, wherein the separating layer 22 is disposed on at least one surface of the reinforcing layer 21, for example, the separating layer 22 may be disposed on any one surface of the reinforcing layer 21, or the separating layers 22 may be disposed on both surfaces of the reinforcing layer 21. Wherein the isolation layer 22 is made of the material provided in the embodiments of the present application.

It should be noted that the reinforcing layer 21 is used to support the isolation layer 22, and the reinforcing layer 21 generally needs to be insoluble in the electrolyte, have good mechanical properties, and the like, so that a polytetrafluoroethylene material can be used to prepare a polytetrafluoroethylene layer as the reinforcing layer 21; of course, other materials with good mechanical properties and being insoluble in the electrolyte can be used to prepare the reinforced layer 21, which is not limited herein.

In addition, the thicknesses of the reinforcing layer 21 and the spacer layer 22 are set according to actual needs. For example, the thickness of the reinforcing layer 21 may be 5 to 20 micrometers, such as 5 micrometers, 10 micrometers, 15 micrometers, 20 micrometers, and the like; the thickness of the isolation layer 22 may be 10 to 20 micrometers, such as 10 micrometers, 12.5 micrometers, 15 micrometers, 15.5 micrometers, 17 micrometers, 17.5 micrometers, 19 micrometers, 20 micrometers, and the like.

For example, 17.5 μm thick separators 22 are provided on both surfaces of a 10 μm thick reinforcing layer 21, and the total thickness of the battery separator 20 is 45 μm.

For convenience of explaining the material for the battery separator, the material preparation method and the technical effects of the battery separator provided by the present application, the following description may be made with reference to specific examples.

Example 1

1.1 functionalization of silicon carbide nanowires

And putting the unfunctionalized silicon carbide nanowires into a mixed solution of sulfuric acid solution and methanol with the concentration of 1mol/L, wherein the mass of the added silicon carbide nanowires is 0.02 times of the volume of the mixed solution of the sulfuric acid solution and the methanol. The reaction was then refluxed at 110 ℃ for 24 hours with a stirring speed of 1000 rpm. And after the reflux reaction is finished, washing the reaction product by using deionized water until the pH value is neutral, and then drying the reaction product in a drying oven at 100 ℃ for 24 hours to obtain gray black powder which is the functionalized silicon carbide nanowire.

1.2 preparation of Perfluorosulfonic acid solution

Preparing a mixed solution of deionized water and n-propanol according to the volume ratio of 1:1, and then adding perfluorinated sulfonic acid resin into the mixed solution, wherein the mass of the added perfluorinated sulfonic acid resin is 1/20 of the mass of the mixed solution. And then transferring the mixed solution into a high-pressure reaction kettle, reacting for 6 hours at 200 ℃, cooling to room temperature after the reaction is finished, and obtaining a clear solution which is a perfluorosulfonic acid solution.

1.3 preparation of materials and preparation of battery diaphragm

Weighing the functionalized silicon carbide nanowire and a perfluorinated sulfonic acid solution according to the mass ratio of the silicon carbide nanowire to the perfluorinated sulfonic acid of 1:20, adding the weighed functionalized silicon carbide nanowire into the weighed perfluorinated sulfonic acid solution, and dispersing by ultrasonic oscillation to obtain the material 1 provided by the embodiment of the application.

Uniformly coating the material 1 on a clean polyimide film substrate, and then covering a polytetrafluoroethylene film with the thickness of about 10 microns on the coating of the material 1 to ensure that the coating of the material 1 is attached to the lower surface of the polytetrafluoroethylene film; after waiting for 10 minutes, the upper surface of the teflon film was further coated with a coating of the material 1, wherein the coating thickness of the upper and lower surfaces of the teflon film could be approximately equal. Then, the film is dried at 100 ℃ for 5 to 60 minutes, and then dried at 160 ℃ for 1 to 3 hours to obtain a battery separator (referred to as a battery separator 1), and the battery separator is peeled off from the polyimide substrate before use.

Through detection, the thickness of the battery diaphragm 1 is 45 microns, and the coatings (as isolating layers) on two sides of the tetrafluoroethylene film (as an enhancement layer) are uniform in texture, compact, free of the dissolution phenomenon of silicon carbide nanowires, and good in flexibility and mechanical performance.

1.4, detecting the performance of the battery diaphragm 1 to obtain the following data:

the battery diaphragm 1 was applied to a vanadium battery, and a performance test was performed for a single vanadium battery: fig. 3 is a graph showing comparison of charge and discharge test data between a vanadium battery using the battery separator 1 (i.e., the PTFE @ PFSA/fSiC composite film in fig. 3) and a conventional vanadium battery (using the Nafion 212 film in fig. 3). As can be seen from fig. 3, the coulombic efficiency, the voltage efficiency and the energy efficiency of the vanadium redox battery using the battery diaphragm 1 are all superior to those of the existing vanadium redox battery, and after multiple cycles, the voltage efficiency and the energy efficiency of the vanadium redox battery using the battery diaphragm 1 are reduced by a small amount compared with those of the existing vanadium redox battery, and have good cycle stability, which also indicates that the service life of the vanadium redox battery using the battery diaphragm 1 is longer than that of the existing vanadium redox battery.

In addition, a plurality of vanadium batteries applying the battery diaphragm 1 are combined into a battery pack to be subjected to performance test: the coulombic efficiency, the voltage efficiency and the energy efficiency of the battery pack are also superior to those of the battery pack consisting of the existing vanadium battery. In addition, since the battery separator 1 uses a polytetrafluoroethylene film, which is inexpensive, as a reinforcing layer, the cost of the battery can be reduced.

Example 2

In example 2, the functionalization of the silicon carbide nanowires and the preparation of the perfluorosulfonic acid solution are the same as those in example 1, except for the material preparation and the battery separator preparation steps.

In the example 2 material preparation and battery separator fabrication steps:

weighing the functionalized silicon carbide nanowire and a perfluorinated sulfonic acid solution according to the mass ratio of the silicon carbide nanowire to the perfluorinated sulfonic acid of 1:200, adding the weighed functionalized silicon carbide nanowire into the weighed perfluorinated sulfonic acid solution, and dispersing by ultrasonic oscillation to obtain a material 2 provided by the embodiment of the application;

uniformly coating the material 2 on a clean polyimide film substrate, and then covering a polytetrafluoroethylene film with the thickness of about 10 microns on the coating of the material 2 to ensure that the lower surface of the polytetrafluoroethylene film is adhered with the coating of the material 2; after waiting for 10 minutes, the upper surface of the teflon film is further coated with a coating of the material 2, wherein the coating thickness of the upper and lower surfaces of the teflon film may be approximately equal. Then, the film is dried at 100 ℃ for 5 to 60 minutes, and then dried at 160 ℃ for 1 to 3 hours to obtain a battery separator (referred to as a battery separator 2), and the battery separator is peeled off from the polyimide substrate before use.

Through detection, the thickness of the battery diaphragm 2 is 41 microns, and the coatings (as isolating layers) on two sides of the tetrafluoroethylene film (as an enhancement layer) are uniform in texture, compact, free of the dissolution phenomenon of the silicon carbide nanowires, and good in flexibility and mechanical performance.

The performance of the battery separator 2 was examined to obtain the following data:

the battery diaphragm 2 was applied to a vanadium battery, and a performance test was performed for a single vanadium battery: the coulombic efficiency, the voltage efficiency and the energy efficiency of the vanadium redox battery applying the battery diaphragm 2 are all superior to those of the existing vanadium redox battery (such as the vanadium redox battery applying the Nafion 212 film), and after multiple cycles, the voltage efficiency and the energy efficiency of the vanadium redox battery applying the battery diaphragm 2 are also superior to those of the existing vanadium redox battery.

However, the coulombic efficiency, the voltage efficiency and the energy efficiency of the vanadium battery using the battery separator 2 are inferior to those of the vanadium battery using the battery separator 1.

Example 3

In example 3, the functionalization of silicon carbide nanowires and the preparation of perfluorosulfonic acid solution are the same as those in example 1, except for the material preparation and the battery separator preparation steps.

In the example 3 material preparation and battery separator fabrication steps:

weighing the functionalized silicon carbide nanowire and a perfluorinated sulfonic acid solution according to the mass ratio of the silicon carbide nanowire to the perfluorinated sulfonic acid of 1:10, adding the weighed functionalized silicon carbide nanowire into the weighed perfluorinated sulfonic acid solution, and dispersing by ultrasonic oscillation to obtain a material 3 provided by the embodiment of the application;

uniformly coating the material 3 on a clean polyimide film substrate, and then covering a polytetrafluoroethylene film with the thickness of about 10 microns on the coating of the material 3 to ensure that the coating of the material 3 is attached to the lower surface of the polytetrafluoroethylene film; after waiting for 10 minutes, the upper surface of the teflon film is further coated with a coating of the material 3, wherein the coating thickness of the upper and lower surfaces of the teflon film may be approximately equal. Then, the film is dried at 100 ℃ for 5 to 60 minutes, and then dried at 160 ℃ for 1 to 3 hours to obtain a battery separator (referred to as a battery separator 3), and the battery separator is peeled off from the polyimide substrate before use.

Through detection, the thickness of the battery diaphragm 3 is 48 microns, and the coatings (as isolating layers) on the two sides of the tetrafluoroethylene film (as an enhancement layer) are uniform in texture, compact, free of the dissolution phenomenon of the silicon carbide nanowires, and good in flexibility and mechanical performance.

The performance of the battery separator 3 was examined to obtain the following data: the coulombic efficiency, the voltage efficiency and the energy efficiency of the vanadium redox battery applying the battery diaphragm 3 are all superior to those of the existing vanadium redox battery (such as the vanadium redox battery applying the Nafion 212 film), and after multiple cycles, the voltage efficiency and the energy efficiency of the vanadium redox battery applying the battery diaphragm 3 are also due to the existing vanadium redox battery. However, the coulombic efficiency, the voltage efficiency and the energy efficiency of the vanadium battery using the battery separator 3 are inferior to those of the vanadium battery using the battery separator 1.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.