An asymmetric separator, a method of making and its use in lithium batteries

Abstract

The application discloses an asymmetric diaphragm, a preparation method and application thereof in lithium batteries, and belongs to the field of high polymer materials and electrochemistry. The asymmetric diaphragm comprises a positive electrode side material layer, a base film and a negative electrode side material layer in sequence; the base film comprises a polypropylene diaphragm or a polyethylene diaphragm; the positive electrode side material layer is composed of a positive electrode side material layer polymer and an inorganic lithium ion conductive active ceramic material; and the negative electrode side material layer is composed of a negative electrode side material layer polymer and an inorganic ceramic material. The asymmetric diaphragm prepared by the method of electrostatic spinning and electrostatic spraying can enhance the interface stability with lithium battery positive and negative electrodes, has good wettability to electrolyte, can enhance Li + transport kinetics and inhibit uncontrollable growth of lithium dendrites, thereby improving the rate performance and long cycle stability of the battery.

Description

Technical Field

[0001] This invention belongs to the fields of polymer materials and electrochemical technology, and more specifically relates to an asymmetric separator, its preparation method, and its application in lithium batteries. Background Technology

[0002] Lithium-ion batteries, with their high operating voltage and specific energy, are crucial energy storage devices. However, with the increasing prevalence of electric vehicles, portable electronic devices, and large-scale energy storage, traditional lithium-ion batteries can no longer meet the demands, necessitating the development of batteries with higher energy density. Compared to graphite anodes, lithium metal, due to its higher specific capacity (3860 mAh / g), has become an ideal material for high-energy-density lithium-ion battery anodes. However, the commercialization of lithium metal batteries has been hampered by inherent scientific challenges. During battery cycling, uneven deposition of lithium ions at the electrode interface leads to the rapid growth of lithium dendrites. The growth of lithium dendrites not only punctures the separator, causing internal short circuits and thermal runaway, but their tips are also prone to breakage, producing "dead lithium," resulting in loss of active material and decreased coulombic efficiency. As a core component separating the positive and negative electrodes and ion transport, the performance of the separator directly determines the battery's electrochemical performance and safety characteristics.

[0003] While widely used polyolefin separators possess good mechanical strength and electrochemical stability, their low-polarity surface groups result in poor wettability with electrolytes, leading to uneven interfacial ion distribution during lithium deposition and further exacerbating dendrite growth. To address these challenges, researchers have conducted extensive modification studies on the separator, a crucial component of batteries. These studies typically involve surface modification of commercial separators, the addition of interlayers, or the creation of custom separators. Previous methods for modifying commercial separators have largely focused on optimizing their morphology and physical properties, including high-temperature stability and mechanical flexibility. Furthermore, most of these optimization efforts have been limited to single-sided or double-sided symmetrical coating modifications, failing to provide differentiated solutions for the asymmetric positive and negative electrode chemical reactions in lithium batteries, thus restricting improvements in overall battery performance.

[0004] In contrast, asymmetric separators designed to address the differences between the positive and negative electrode materials can simultaneously meet the different requirements of the positive and negative electrode interfaces by imparting different physicochemical properties to the two sides of the separator. Therefore, the fabrication of high-performance asymmetric separators using suitable materials and reasonable processes is of great significance to the development of lithium batteries. Summary of the Invention

[0005] The purpose of this invention is to provide an asymmetric separator, its preparation method, and its application in lithium batteries, thereby solving the problems existing in the prior art. The asymmetric separator prepared by this invention using a combination of electrospinning and electrospraying can enhance the interfacial stability with the positive and negative electrodes of lithium batteries, exhibit good wettability to the electrolyte, and enhance the performance of Li-ion batteries. + This improves battery rate performance and long-cycle stability by mitigating transport dynamics and suppressing uncontrolled lithium dendrite growth.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] One of the technical solutions of the present invention is to provide an asymmetric separator, wherein the asymmetric separator comprises, in sequence, a positive electrode side material layer, a base membrane, and a negative electrode side material layer; the positive electrode side material layer is the material layer on the side of the asymmetric separator that is closest to the positive electrode; the negative electrode side material layer is the material layer on the side of the asymmetric separator that is closest to the negative electrode.

[0008] The base membrane includes a polypropylene diaphragm or a polyethylene diaphragm;

[0009] The positive electrode side material layer is composed of a positive electrode side material layer polymer and an inorganic lithium-ion conductive active ceramic material; the positive electrode side material layer polymer includes one or more of polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), and polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP); the inorganic lithium-ion conductive active ceramic material includes Li 1.3 Al 0.3 Ti 1.7 P3O 12 (LATP) and / or Li 1.5 Al 0.5 Ge 1.5 P3O 12 (LAGP);

[0010] The negative electrode side material layer is composed of a negative electrode side material layer polymer and inorganic ceramic materials; the negative electrode side material layer polymer includes polymethyl methacrylate (PMMA) and / or poly(m-phenylene isophthalamide) (PMIA); the inorganic ceramic materials include nano-zirconium dioxide (ZrO2), nano-titanium dioxide (TiO2), nano-zinc oxide (ZnO), nano-silicon dioxide (SiO2), and Li7La3Zr2O. 12 (LLZO) and Li 6.5 La3Zr 1.5 Ta 0.5 O 12 At least one of (LLZTO).

[0011] Preferably, the thickness of the positive electrode side material layer is 1~50μm; the thickness of the base film is 3~40μm; and the thickness of the negative electrode side material layer is 1~50μm.

[0012] The second technical solution of the present invention provides a method for preparing the above-mentioned asymmetric membrane, comprising the following steps:

[0013] The polymer of the positive electrode side material layer is dissolved in a polar solvent to obtain the first electrospinning solution;

[0014] Inorganic lithium-ion conductive active ceramic material was dissolved in ethanol to obtain the first electrostatic spray solution.

[0015] The polymer of the negative electrode side material layer is dissolved in a polar solvent to obtain a second electrospinning solution;

[0016] Inorganic ceramic materials are dissolved in ethanol to obtain a second electrostatic spray solution;

[0017] Take a base membrane, and form a positive electrode material layer on one side of the base membrane by the first electrospinning solution and the first electrospray solution through the first electrospinning and the first electrospray. Form a negative electrode material layer on the other side of the base membrane by the second electrospinning solution and the second electrospray solution through the second electrospinning and the second electrospray, thus obtaining the asymmetric separator.

[0018] Preferably, the mass ratio of the polymer in the positive electrode side material layer to the polar solvent in the first electrospinning solution is 0.03~0.3:1. Different types of polymers in the positive electrode side material layer require different polar solvents. It is necessary to ensure that the polymer in the positive electrode side material layer can dissolve well to form a transparent solution without suspension. The concentration of the first electrospinning solution must be controlled within a range suitable for spinning. Different polymers have different solubility properties, and this concentration will vary accordingly.

[0019] Preferably, the mass ratio of inorganic lithium-ion conductive active ceramic material to ethanol in the first electrostatic spray solution is 0.001~1.5:1. The first electrostatic spray solution is a suspension containing inorganic components, and the inorganic lithium-ion conductive active ceramic material cannot be dissolved. Therefore, the concentration of the first electrostatic spray solution must ensure that the inorganic lithium-ion conductive active ceramic material can be stably sprayed out during the spraying process.

[0020] Preferably, the mass ratio of the polymer in the negative electrode side material layer to the polar solvent in the second electrospinning solution is 0.03~0.3:1. Different types of polymers in the negative electrode side material layer require different polar solvents. It is necessary to ensure that the polymer in the negative electrode side material layer can dissolve well to form a transparent solution without suspension. The concentration of the second electrospinning solution must be controlled within a range suitable for spinning. Different polymers have different solubility properties, and this concentration will vary accordingly.

[0021] Preferably, the mass ratio of inorganic ceramic material to ethanol in the second electrostatic spray solution is 0.001~1.5:1. The second electrostatic spray solution is a suspension containing inorganic components, and the nano-inorganic particles cannot be dissolved. Therefore, the concentration of the second electrostatic spray solution must ensure that the inorganic ceramic material can be stably sprayed out during the spraying process.

[0022] Preferably, the parameters of the first electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters of the first electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm.

[0023] Preferably, the parameters for the second electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters for the second electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm.

[0024] The third technical solution of the present invention is to provide the application of the above-mentioned asymmetric separator in lithium batteries.

[0025] The nanofibers formed by spinning in the asymmetric diaphragm of this invention have widths in the nanometer range and an average length of not less than 500 μm, and these fibers intersect to form a three-dimensional network structure. Inorganic ceramic material particles on both the positive and negative electrode sides are uniformly and densely dispersed within the polymer fiber three-dimensional network structure. The long fiber structure of the polymer ensures point / line contact between it and the inorganic ceramic material.

[0026] Traditional polyolefin separators suffer from poor electrolyte wettability due to their low-polarity surface groups, leading to uneven interfacial ion distribution during lithium deposition and further exacerbating uncontrolled lithium dendrite growth. Furthermore, existing single-sided or double-sided symmetrical coatings on modified separators cannot provide differentiated solutions for the asymmetric positive and negative electrode chemical reactions in lithium batteries, limiting the improvement of overall battery performance. This invention utilizes a combined electrospinning and electrospraying technique to prepare an asymmetric separator that enhances electrolyte wettability and optimizes Li… + Transmission path, enhanced Li + This involves optimizing lithium transport kinetics and suppressing uncontrolled lithium dendrite growth, thereby improving the electrochemical performance of lithium batteries (such as rate performance and cycle stability). Specifically: Li 1.3 Al 0.3 Ti 1.7 P3O 12and / or Li 1.5 Al 0.5 Ge 1.5 P3O 12 It is an active inorganic ceramic material, namely a lithium-ion conductor, which can participate in Li... + This increases the transport of lithium ions, adding additional lithium-ion transport pathways. Furthermore, inorganic ceramic materials such as nano-zirconium dioxide, nano-titanium dioxide, nano-zinc oxide, nano-silica, nano-alumina, and Li7La3Zr2O are used. 12 and Li 6.5 La3Zr 1.5 Ta 0.5 O 12 Selective adsorption of anions in electrolytes enhances Li + Transport kinetics and homogenization of lithium flux. Furthermore, both the ceramic and polymer materials modified on the positive electrode side possess high-voltage resistance, which is beneficial for improving positive electrode stability and promoting the formation of CEI on the positive electrode side; while the inorganic ceramic and polymer materials modified on the negative electrode side are both lithium-stabilizing, promoting the formation of a stable SEI, and their uniform dispersion characteristics also help homogenize lithium flux and suppress lithium dendrite formation. From Figure 3 , Figures 4-7 A comparison of constant current cycling tests using commercially available polypropylene separators and the asymmetric separators prepared by the present invention through a combination of electrospinning and electrospraying technologies leads to the conclusion that the asymmetric separators prepared by the combination of electrospinning and electrospraying technologies can suppress dendrite growth and improve the electrochemical performance of lithium batteries (such as rate performance and cycle stability).

[0027] This invention utilizes a combined electrospinning and electrospraying technique to prepare asymmetric membranes. A substrate membrane is used as the receiving substrate for electrospinning / spraying. Polymer nanowires are prepared via electrospinning, while simultaneously, nano-inorganic ceramic particles are sprayed between the polymer nanowires using electrospraying. Both electrospinning and electrospraying are performed concurrently. Compared to electrospinning alone, the combined use of electrospinning and electrospraying significantly improves the content and dispersion uniformity of the inorganic ceramic material. Without this combined technique, if electrospinning is used alone, for example, in PMMA spinning solutions, a ZrO2 content exceeding 5 wt% will cause uneven ZrO2 dispersion, leading to bead formation and spinning instability. Furthermore, in... Figure 3 , Figures 6-7In the constant current cycling test comparison, it can be found that the lithium symmetric battery assembled with the separator prepared by the present invention exhibits a long cycle time, and the capacity retention rate is significantly improved when matched with different positive electrode materials. This indicates that the interface stability between the separator prepared by the present invention using the combined electrospinning and electrospraying technology and the positive and negative electrodes is enhanced (the present invention selects ceramics and polymers that are more stable to the positive and negative electrodes, thus ensuring that the interface stability is enhanced).

[0028] This invention provides a controllable and adjustable method for preparing electrospun / sprayed composite modified layers using electrospinning and electrospraying. Specifically, the method described in this invention can also prepare composite films with high inorganic ceramic material content, where the inorganic ceramic material content in the modified layer can exceed 96%, and the Li on the positive electrode side... 1.3 Al 0.3 Ti 1.7 P3O 12 and / or Li 1.5 Al 0.5 Ge 1.5 P3O 12 A high content of active inorganic ceramic materials is key to improving rate performance and cycle stability. These inorganic materials exert a "solid-liquid synergistic" effect, constructing rapid lithium-ion transport channels on and within the separator surface, thereby reducing ion migration resistance and shortening the migration path. Furthermore, a high content of inorganic ceramic materials on the negative electrode side can better selectively adsorb anions in the electrolyte, homogenize lithium flux, and enhance its mechanical strength, effectively resisting the growth and puncture of lithium dendrites during cycling, fundamentally preventing short circuits. Therefore, a high content of inorganic ceramic materials significantly improves the rate performance and long-term cycle stability of the battery.

[0029] The present invention discloses the following technical effects:

[0030] This invention provides a separator prepared by electrospinning / spraying on both sides of a base membrane, in which the inorganic and organic parts are uniformly and densely dispersed on the surface of the base membrane. Symmetrical cells assembled using this membrane exhibit reduced polarization and longer cycle life. Li / LiFePO4 (LFP) cells assembled using this membrane exhibit better rate performance in the voltage range of 2.7~4V and higher capacity retention under long cycles. Li / LiCoO2 cells assembled using this membrane exhibit higher capacity retention under long cycles in the voltage range of 2.8~4.3V. Attached Figure Description

[0031] Figure 1 This is a SEM image of the side of the electrospun PAN / electrosprayed LATP in Example 1;

[0032] Figure 2 This is a SEM image of the side of PMMA / ZrO2 obtained by electrospinning in Example 1;

[0033] Figure 3 A constant current long-cycle comparison diagram of assembling Li symmetric cells using the separator obtained in Example 1 and the PP separator;

[0034] Figure 4 Impedance comparison diagram of Li symmetric cells assembled using the separator obtained in Example 1 and the PP separator;

[0035] Figure 5 A rate comparison chart showing the assembly of Li / LFP cells using the separator obtained in Example 1 and the PP separator;

[0036] Figure 6 A comparison of constant current charge and discharge of Li / LFP batteries assembled using the separator obtained in Example 1 and the PP separator;

[0037] Figure 7 This is a comparison chart of constant current charge and discharge of Li / LCO batteries assembled using the separator obtained in Example 1 and the PP separator. Detailed Implementation

[0038] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0041] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0042] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0043] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0044] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of this invention are commercially available products, and the source of these commercially available products does not affect the technical effect of this invention.

[0045] Unless otherwise specified, the room temperature in this invention is 25±5℃.

[0046] Example 1

[0047] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0048] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0049] The morphology of both sides of the diaphragm prepared in this embodiment is as follows: Figure 1 and Figure 2As shown, on one side of the basement membrane, the PAN polymer, after electrospinning, forms nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed within the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, on the other side of the basement membrane, the PMMA polymer, after electrospinning, forms nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed within the PMMA three-dimensional network structure, with ZrO2 particle sizes between 200 and 400 nm.

[0050] The separator prepared in this embodiment was used to assemble a Li / Li symmetric battery (the electrolyte was LB-015 (purchased from Suzhou Duoduo Chemical Co., Ltd.), the coin cell model was CR2302, the control sample separator was a polypropylene (PP) separator, and constant current charge-discharge tests were performed using Xinwei Battery Testing Equipment). Figure 3 Impedance testing was performed using the Chenhua electrochemical workstation. Figure 4 It can be seen that the diaphragm prepared using this embodiment has a performance of 1 mA / cm². 2 ~1mAh / cm 2 The lower polarization and longer cycle time exhibited under these conditions indicate that the membrane prepared in this embodiment has a closer contact with the lithium electrode, effectively reducing interfacial impedance. Furthermore, the membrane prepared in this embodiment can optimize the lithium-ion transport path, promote uniform lithium-ion deposition, suppress lithium dendrites, and achieve longer cycle life. Figure 3 The symmetrical cycling diagram illustrates this. Further, Li / LiFePO4 (LFP) batteries were assembled using the separator prepared in this embodiment for rate charge-discharge testing. The operating voltage was set to 2.7~4V, and the batteries were cycled 5 times at rates of 0.1C, 0.5C, 1C, 5C, and 10C. It can be seen that the separator prepared in this embodiment exhibits better rate performance compared to the comparative separator. Figure 5 Furthermore, the separator prepared in this embodiment was used to assemble a Li / LFP battery (electrolyte: 1M LiPF6 in DEC:EC = 1:1 Vol% with 5% FEC; negative electrode: lithium metal; positive electrode: lithium iron phosphate) for constant current charge-discharge testing. The operating voltage was set to 2.7~4V, and long-term cycling was performed at 1C. It can be seen that compared with the control sample separator, the separator prepared in this embodiment has better cycle stability and higher capacity retention after 300 cycles. Figure 6Next, the separator prepared in this embodiment was used to assemble a Li / LiCoO2 battery (electrolyte: 1M LiPF6 in DEC:EC = 1:1 Vol% with 5% FEC; negative electrode: lithium metal; positive electrode: lithium cobalt oxide) for constant current charge-discharge testing. The operating voltage was set to 2.8~4.3V, and long-term cycling was performed at 0.5C. It can be seen that compared with the comparative separator, the separator prepared in this embodiment has better cycle stability and higher capacity retention after 150 cycles under high voltage. Figure 7 ).

[0051] Comparative Example 1

[0052] A commercial polypropylene (PP) membrane with a thickness of 26 μm was used as a control sample. The battery assembly method was the same as that of the membrane assembly method in Example 1 (the sample in Example 1 is named LPZ in the figure, and the control sample is named PP in the figure).

[0053] Example 2

[0054] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMIA was dispersed in 10 g of N,N-dimethylacetamide (DMAC) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0055] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0056] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMIA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 1000 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMIA three-dimensional network structure, with ZrO2 particle sizes between 200 and 400 nm.

[0057] Example 3

[0058] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of TiO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 1400 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0059] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0060] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and TiO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with TiO2 particle sizes between 50 and 200 nm.

[0061] Example 4

[0062] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of SiO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0063] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0064] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and SiO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with SiO2 particle sizes between 7 and 40 nm.

[0065] Example 5

[0066] 1 g of PVDF was dispersed in a solution of 6 g N,N-dimethylformamide (DMF) and 4 g acetone (AC), and stirred at 1200 r / min for 12 h at 60 °C to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in a solution of 18.5 g anhydrous ethanol, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in a solution of 10 g N,N-dimethylformamide (DMF), and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in a solution of 18.5 g anhydrous ethanol, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 10 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0067] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0068] In this embodiment, PVDF polymer on one side of the basement membrane is electrospun to form nanoscale long fibers with a diameter between 300 and 800 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure. The LATP particle size is between 200 and 400 nm. Similarly, on the other side of the basement membrane, PMMA polymer is electrospun to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure. The ZrO2 particle size is between 200 and 400 nm.

[0069] Example 6

[0070] 1 g of PVDF-HFP was dispersed in a solution of 7 g N,N-dimethylformamide (DMF) and 3 g acetone (AC), and stirred at 1200 r / min for 12 h at 60 °C to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in a solution of 18.5 g anhydrous ethanol, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in a solution of 10 g N,N-dimethylformamide (DMF), and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in a solution of 18.5 g anhydrous ethanol, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 12 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0071] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0072] In this embodiment, PVDF-HFP polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure. The LATP particle size is between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure. The ZrO2 particle size is between 200 and 400 nm.

[0073] Example 7

[0074] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LAGP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0075] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0076] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LAGP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with a particle size between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with a particle size between 200 and 400 nm.

[0077] Example 8

[0078] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 10 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 10 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0079] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 3 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0080] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with ZrO2 particle sizes between 200 and 400 nm.

[0081] Example 9

[0082] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1.5 g of LATP was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1.5 g of ZrO2 was dispersed in 18.5 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and the injection rate for electrospraying was 0.15 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 1 hour. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.15 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 1 hour. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 hours. After drying, place it on a roller press for rolling.

[0083] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 28 μm, and the mass ratio of inorganic matter to organic matter is 96:4.

[0084] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with ZrO2 particle sizes between 200 and 400 nm.

[0085] Example 10

[0086] 1 g of PAN was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at room temperature to obtain the first electrospinning solution. 1 g of LATP was dispersed in 19 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the first electrospray solution. 1 g of PMMA was dispersed in 10 g of N,N-dimethylformamide (DMF) solution and stirred at 1200 r / min for 12 h at 60 °C to obtain the second electrospinning solution. 1 g of ZrO2 was dispersed in 19 g of anhydrous ethanol solution, sonicated for 1 h, and then stirred at 1000 r / min for 12 h at room temperature to obtain the second electrospray solution. One side of a polypropylene (PP) diaphragm (26 μm thick) was placed on a collecting drum rotating at 140 r / min. Appropriate amounts of the first spinning solution and the first spraying solution were drawn up using a syringe and placed into the electrospinning and electrospraying devices respectively (the stainless steel needles used for electrospinning were model 23G, and those used for electrospraying were model 20G). The electrospinning and electrospraying devices were simultaneously turned on (the injection rate for electrospinning was 0.005 mL / min, and for electrospraying it was 0.056 mL / min; the negative pressure for both electrospinning and electrospraying was -1 kV, and the positive pressure was +18 kV; the electrospinning distance was 15 cm, and the electrospraying distance was fixed at 5 cm). The time for both electrospinning and electrospraying was 5 min. After spinning / spraying is complete on one side of the PP diaphragm, remove it. Place the other side on a collecting roller rotating at 140 r / min. Use a syringe to draw appropriate amounts of the second spinning solution and the second spray solution and place them respectively into the electrospinning and electrospraying equipment (the stainless steel needle used for electrospinning is model 23G, and the stainless steel needle used for electrospraying is model 20G). Simultaneously turn on the electrospinning and electrospraying equipment (the injection rate for electrospinning is 0.005 mL / min, and the injection rate for electrospraying is 0.056 mL / min; the negative pressure for both electrospinning and electrospraying is -1 kV, and the positive pressure is +18 kV; the electrospinning distance is 15 cm, and the electrospraying distance is fixed at 5 cm). The time for both electrospinning and electrospraying is 5 min. After spinning / spraying is complete on both sides, remove the diaphragm and place it in an 80℃ vacuum oven to dry for 24 h. After drying, place it on a roller press for rolling.

[0087] The thickness of the spinning spray layer on both sides of the diaphragm prepared in this embodiment is 1 μm, and the mass ratio of inorganic matter to organic matter is 90:10.

[0088] In this embodiment, PAN polymer is electrospun on one side of the basement membrane to form nanoscale long fibers with a diameter between 100 and 300 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and LATP nanoparticles are uniformly and densely dispersed in the PAN three-dimensional network structure, with LATP particle sizes between 200 and 400 nm. Similarly, PMMA polymer is electrospun on the other side of the basement membrane to form nanoscale long fibers with a diameter between 200 and 500 nm and an average length of not less than 500 μm. These fibers intersect to form a three-dimensional network structure, and ZrO2 nanoparticles are uniformly and densely dispersed in the PMMA three-dimensional network structure, with ZrO2 particle sizes between 200 and 400 nm.

[0089] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0090] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An asymmetric diaphragm, characterized in that, The asymmetric separator comprises, in sequence, a positive electrode side material layer, a base membrane, and a negative electrode side material layer; the positive electrode side material layer is the material layer on the side of the asymmetric separator closest to the positive electrode; the negative electrode side material layer is the material layer on the side of the asymmetric separator closest to the negative electrode. The base membrane includes a polypropylene diaphragm or a polyethylene diaphragm; The positive electrode side material layer is composed of a positive electrode side material layer polymer and an inorganic lithium-ion conductive active ceramic material; the positive electrode side material layer polymer includes one or more of polyacrylonitrile, polyvinylidene fluoride, and polyvinylidene fluoride-co-hexafluoropropylene; the inorganic lithium-ion conductive active ceramic material includes Li 1.3 Al 0.3 Ti 1.7 P3O 12 and / or Li 1.5 Al 0.5 Ge 1.5 P3O 12 ; The negative electrode side material layer is composed of a negative electrode side material layer polymer and inorganic ceramic materials; the negative electrode side material layer polymer includes polymethyl methacrylate and / or poly(m-phenylene isophthalamide); the inorganic ceramic materials include nano-zirconia, nano-titanium dioxide, nano-zinc oxide, nano-silica, nano-alumina, and Li7La3Zr2O. 12 and Li 6.5 La3Zr 1.5 Ta 0.5 O 12 At least one of them; The thickness of the positive electrode side material layer is 1~50 μm; the thickness of the base film is 3~40 μm; the thickness of the negative electrode side material layer is 1~50 μm; both the positive electrode side material layer and the negative electrode side material layer in the asymmetric separator are prepared by a combination of spinning and spraying. The width of the nanofibers formed by spinning is in the nanometer range, the average length is not less than 500 μm, and the nanofibers intersect to form a three-dimensional network structure; the inorganic lithium-ion conductive active ceramic material on the positive electrode side and the inorganic ceramic material on the negative electrode side are uniformly and densely dispersed in their respective three-dimensional network structures. The long fiber structure of the polymer in the positive electrode side material layer and the polymer in the negative electrode side material layer can ensure that they contact the inorganic lithium-ion conductive active ceramic material and the inorganic ceramic material in a point / line manner; The method for preparing the asymmetric membrane includes the following steps: The polymer of the positive electrode side material layer is dissolved in a polar solvent to obtain the first electrospinning solution; Inorganic lithium-ion conductive active ceramic material was dissolved in ethanol to obtain the first electrostatic spray solution. The polymer of the negative electrode side material layer is dissolved in a polar solvent to obtain a second electrospinning solution; Inorganic ceramic materials are dissolved in ethanol to obtain a second electrostatic spray solution; Take a base membrane, and form a positive electrode side material layer on one side of the base membrane by the first electrospinning solution and the first electrospray solution through the first electrospinning and the first electrospray. Form a negative electrode side material layer on the other side of the base membrane by the second electrospinning solution and the second electrospray solution through the second electrospinning and the second electrospray, thus obtaining the asymmetric separator. The parameters for the first electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters for the first electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm. The parameters for the second electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters for the second electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm. The mass ratio of polymer to polar solvent in the positive electrode side material layer of the first electrospinning solution is 0.03~0.3:1; the mass ratio of inorganic lithium-ion conductive active ceramic material to ethanol in the first electrospray solution is 0.001~1.5:1; the mass ratio of polymer to polar solvent in the negative electrode side material layer of the second electrospinning solution is 0.03~0.3:1; and the mass ratio of inorganic ceramic material to ethanol in the second electrospray solution is 0.001~1.5:

1.

2. The method for preparing the asymmetric diaphragm according to claim 1, characterized in that, Includes the following steps: The polymer of the positive electrode side material layer is dissolved in a polar solvent to obtain the first electrospinning solution; Inorganic lithium-ion conductive active ceramic material was dissolved in ethanol to obtain the first electrostatic spray solution. The polymer of the negative electrode side material layer is dissolved in a polar solvent to obtain a second electrospinning solution; Inorganic ceramic materials are dissolved in ethanol to obtain a second electrostatic spray solution; Take a base membrane, and form a positive electrode side material layer on one side of the base membrane by the first electrospinning solution and the first electrospray solution through the first electrospinning and the first electrospray. Form a negative electrode side material layer on the other side of the base membrane by the second electrospinning solution and the second electrospray solution through the second electrospinning and the second electrospray, thus obtaining the asymmetric separator. The parameters for the first electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters for the first electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm. The parameters for the second electrospinning are set as follows: injection speed of 0.005 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospinning distance of 5 to 20 cm; the parameters for the second electrospraying are set as follows: injection speed of 0.056 to 0.15 mL / min, negative pressure of -1 to -10 kV, positive pressure of +8 to +25 kV, and electrospraying distance of 3 to 8 cm. The mass ratio of polymer to polar solvent in the positive electrode side material layer of the first electrospinning solution is 0.03~0.3:1; the mass ratio of inorganic lithium-ion conductive active ceramic material to ethanol in the first electrospray solution is 0.001~1.5:1; the mass ratio of polymer to polar solvent in the negative electrode side material layer of the second electrospinning solution is 0.03~0.3:1; and the mass ratio of inorganic ceramic material to ethanol in the second electrospray solution is 0.001~1.5:

1.

3. The application of the asymmetric separator according to claim 1 in lithium batteries.

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