An inorganic-organic composite fiber layer, its preparation method and application

Abstract

This application discloses an inorganic-organic composite fiber layer, its preparation method, and its application. The inorganic-organic composite fiber layer comprises, by mass percentage, 40%-70% inorganic skeleton fibers, 20%-50% organic toughening fibers, and 1%-10% an interface anchoring system. The inorganic skeleton fibers are one or more of glass fibers, alumina fibers, or ceramic fibers. The organic toughening fibers are one or more of polyethylene fibers, polypropylene fibers, polystyrene fibers, polyacrylonitrile fibers, polyimide fibers, polyethylene terephthalate fibers, epoxy resin fibers, or phenolic resin fibers. The interface anchoring system includes a coupling agent and a pH adjuster, and is used to anchor the inorganic fiber skeleton and the organic toughening fibers to the surface of a substrate material.

Description

Technical Field

[0001] This specification relates to the field of new energy battery materials technology, and in particular to an inorganic-organic composite fiber layer, its preparation method and application. Background Technology

[0002] Electrodeless batteries achieve a breakthrough by eliminating the traditional graphite anode. During initial charging, lithium ions migrate from the positive electrode and deposit to form a functional anode. Electrodeless sodium-ion batteries have become a hot topic in next-generation energy storage technology due to their extremely high theoretical energy density. However, because there is no initial active anode material, sodium metal is directly deposited / stripped onto the current collector surface, facing severe dendrite growth and a significant volumetric breathing effect.

[0003] In existing technologies, anode-free sodium-ion batteries are mostly achieved by coating the base film surface with ceramic particles or simple non-woven fabric. Specifically, this can be achieved through physical coating, surface modification, or direct lamination. Physical coating involves mixing inorganic particles with a binder (such as PVDF) to form a slurry and then coating it onto the base film. Surface modification uses magnetron sputtering or atomic layer deposition to modify the surface into a thin film layer. Direct lamination involves directly stacking an organic fiber film onto the base film. Physical coatings rely on van der Waals forces or simple physical adhesion. During the charge-discharge cycle of anode-free sodium batteries, the enormous stress generated by sodium deposition and electrolyte swelling can easily cause the coating to crack and peel off, losing its protective function. Therefore, interfacial peeling and powdering occur. Pure polymer fiber films have low modulus and cannot withstand the vertical penetration of sodium dendrites; pure inorganic fibers (such as glass fiber) are brittle and cannot meet the requirements of battery manufacturing processes such as winding, thus resulting in insufficient mechanical strength. The existing coatings lack active induction sites for sodium ions, resulting in a high sodium nucleation barrier, uneven deposition, and poor nucleation kinetics.

[0004] Therefore, there is a need for an inorganic-organic composite fiber layer, its preparation method, and its application. Summary of the Invention

[0005] This specification provides an inorganic-organic composite fiber layer, its preparation method, and its application to address the following technical problems: In the prior art, physical coatings rely on van der Waals forces or simple physical adhesion. During charge-discharge cycles without a negative electrode, the enormous stress generated by sodium deposition and electrolyte swelling can easily cause the coating to crack and peel off, losing its protective function. Therefore, interfacial peeling and powdering occur. Pure polymer fiber films have low modulus and cannot withstand the vertical penetration of sodium dendrites; pure inorganic fibers (such as glass fiber) are brittle and cannot meet the requirements of battery manufacturing processes such as winding, thus resulting in insufficient mechanical strength. Existing coatings lack active induction sites for sodium ions, leading to high sodium nucleation barriers, uneven deposition, and poor nucleation kinetics.

[0006] To solve the above-mentioned technical problems, the embodiments in this specification are implemented as follows: This specification provides an inorganic-organic composite fiber layer, characterized in that the inorganic-organic composite fiber layer consists of 40%-70% inorganic skeleton fibers, 20%-50% organic toughness fibers, and 1%-10% interface anchoring system by mass percentage. in, The inorganic skeleton fiber is one or more of glass fiber, alumina fiber or ceramic fiber; The organic tough fiber is one or more of polyethylene fiber, polypropylene fiber, polystyrene fiber, polyacrylonitrile fiber, polyimide fiber, polyethylene terephthalate fiber, epoxy resin fiber or phenolic resin fiber. The interface anchoring system includes a coupling agent and a pH adjuster, and is used to anchor the inorganic fiber skeleton and the organic tough fiber to the surface of the substrate material.

[0007] Further, the ceramic fiber is Na-β-Al2O3 ceramic fiber and / or NZSP ceramic fiber, wherein the NZSP ceramic fiber is... , 0≤x≤3.

[0008] Furthermore, the coupling agent is a silane coupling agent or a titanate / zirconate coupling agent, and the pH adjuster is glacial acetic acid.

[0009] Furthermore, the X group of the silane coupling agent is methoxy or ethoxy, and the Y group of the silane coupling agent is determined according to the type of organic tough fiber; If the organic tough fiber is epoxy resin or phenolic resin fiber, then the silane coupling agent is γ-glycidoxypropyltrimethoxysilane. If the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, then the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. If the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, then the silane coupling agent is γ-aminopropyltriethoxysilane.

[0010] Furthermore, the substrate material is a current collector or a diaphragm; The current collector is aluminum foil, carbon-coated aluminum foil, copper foil, or carbon-coated copper foil; The diaphragm is a single-layer or multi-layer composite microporous membrane of polypropylene or polyethylene.

[0011] This specification also provides a method for preparing an inorganic-organic composite fiber layer, the method comprising: The inorganic skeleton fiber, organic tough fiber and substrate material are surface activated by chemical oxidation or plasma treatment to obtain activated inorganic skeleton fiber, activated organic tough fiber and activated substrate material. The activated organic tough fibers and the activated inorganic skeleton fibers are dispersed in a silanol hydrolysate at a mass ratio of 3:7-7:3 to form a dilute solution with a mass concentration of 1%-5%. The solution is stirred at 40-60°C for 1-2 hours to generate a slurry. The slurry concentration is diluted with deionized water to a mass fraction of 0.01%-0.05%. After adding a dispersant with a mass fraction of 0.05%-0.1% of the total fiber mass, the slurry is flowed at high speed on a forming mesh at an inclination angle of 15-30 degrees and vacuum dewatered. By adjusting the fiber aspect ratio, the slurry concentration on the forming mesh, and the vacuum box suction, the porosity of the wet fiber web is precisely controlled at 60%-85%. After the wet fiber web leaves the forming mesh, it is transferred by a vacuum suction roller and directly covers the surface of the activated substrate material in an undried state to form a composite. The composite is kept at 100°C for 1-10 hours and then in-situ hot-pressed and anchored to form the inorganic-organic composite fiber layer.

[0012] Further, the silanol is generated by the following method: adding a silane coupling agent equivalent to 1.0%-3.0% of the total fiber mass to deionized water; adjusting the pH of the solution to 3.5-5.5 with glacial acetic acid; and stirring for 30-60 minutes to allow the silane to be fully hydrolyzed to generate silanol. The silane coupling agent is determined based on the type of organic tough fiber. If the organic tough fiber is epoxy resin or phenolic resin fiber, the silane coupling agent is γ-glycidoxypropyltrimethoxysilane; if the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane; if the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0013] Furthermore, the dispersant is one or more of polyacrylamide, polyethylene oxide, carboxymethyl cellulose, or hydroxypropyl methyl cellulose.

[0014] Furthermore, the aspect ratio of the adjusting fiber is 3-6 mm, the online concentration of the slurry is 0.01 wt% - 0.05 wt%, and the suction force of the vacuum box is 1-5 kPa in the wet section and 10-35 kPa in the forming section.

[0015] This specification also provides an application of an inorganic-organic composite fiber layer in a sodium-ion battery without a negative electrode.

[0016] The inorganic-organic composite fiber layer provided in the embodiments of this specification has extremely high interfacial bonding strength, solving the industry pain point of easy powder shedding in ceramic coatings. Experiments have shown that its peel strength is 3-5 times higher than that of traditional physical coatings. The inorganic skeleton fiber provides rigid puncture resistance, while the organic fiber ensures tensile strength and good preparation ability, with a good balance between mechanical toughness and strength. It has optimized sodium deposition kinetics, which reduces sodium deposition overpotential through polar fiber network and abundant sodium-loving sites, while achieving a high coulombic efficiency of over 99.9% and long cycle performance in a negative electrode-free system. It adopts low-cost wet web forming technology, and the equipment is compatible with the paper industry, making it easy to mass-produce and avoiding expensive processes such as magnetron sputtering. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram illustrating a method for preparing an inorganic-organic composite fiber layer as provided in the embodiments of this specification; Figure 2 This is a schematic diagram of an inorganic-organic composite fiber layer structure provided in the embodiments of this specification; Figure 3 This is a schematic diagram of another inorganic-organic composite fiber layer structure provided in the embodiments of this specification; Figure 4 A schematic diagram of the battery performance test results for Example 1 provided in this specification; Figure 5 A schematic diagram of the battery performance test results for Example 2 provided in this specification; Figure 6 A schematic diagram of the battery performance test results for Comparative Example 1 provided in this specification; Figure 7 This is a schematic diagram of the battery test results for Comparative Example 1 provided in the embodiments of this specification. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0020] This specification provides an inorganic-organic composite fiber layer, characterized in that the inorganic-organic composite fiber layer consists of 40%-70% inorganic skeleton fibers, 20%-50% organic toughness fibers, and 1%-10% interface anchoring system by mass percentage. in, The inorganic skeleton fiber is one or more of glass fiber, alumina fiber or ceramic fiber; The organic tough fiber is one or more of polyethylene fiber, polypropylene fiber, polystyrene fiber, polyacrylonitrile fiber, polyimide fiber, polyethylene terephthalate fiber, epoxy resin fiber or phenolic resin fiber. The interface anchoring system includes a coupling agent and a pH adjuster, and is used to anchor the inorganic fiber skeleton and the organic tough fiber to the surface of the substrate material.

[0021] In the embodiments described in this specification, the ceramic fiber is Na-β-Al2O3 ceramic fiber and / or NZSP ceramic fiber, wherein the NZSP ceramic fiber is , 0≤x≤3.

[0022] In the embodiments of this specification, the coupling agent is a silane coupling agent or a titanate / zirconate coupling agent, and the pH adjuster is glacial acetic acid.

[0023] In the embodiments of this specification, the X group of the silane coupling agent is methoxy or ethoxy, and the Y group of the silane coupling agent is determined according to the type of organic tough fiber; If the organic tough fiber is epoxy resin or phenolic resin fiber, then the silane coupling agent is γ-glycidoxypropyltrimethoxysilane. If the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, then the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. If the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, then the silane coupling agent is γ-aminopropyltriethoxysilane.

[0024] In the embodiments described in this specification, the substrate material is a current collector or a diaphragm; The current collector is aluminum foil, carbon-coated aluminum foil, copper foil, or carbon-coated copper foil; The diaphragm is a single-layer or multi-layer composite microporous membrane of polypropylene or polyethylene.

[0025] The above description details an inorganic-organic composite fiber layer. Correspondingly, this specification also provides a method for preparing an inorganic-organic composite fiber layer. Figure 1 This is a schematic diagram illustrating a method for preparing an inorganic-organic composite fiber layer provided in the embodiments of this specification, as shown below. Figure 1 As shown in the embodiments of this specification, a method for preparing an inorganic-organic composite fiber layer is provided. The preparation method is used for inorganic-organic composite fiber layers and includes: Step S101: The inorganic skeleton fiber, organic tough fiber and substrate material are surface activated by chemical oxidation or plasma treatment to obtain activated inorganic skeleton fiber, activated organic tough fiber and activated substrate material.

[0026] In the embodiments of this specification, the chemical oxidation method is as follows: the above materials (inorganic skeleton fiber, organic tough fiber, and substrate material) are placed in 100 mL of hydrogen peroxide solution with a concentration of 30 wt% at a mass of 3g or at a surface area of ​​0.01 m2, and ultrasonically treated at 40°C for 30 minutes. After removal, they are washed with deionized water until neutral and dried.

[0027] Plasma treatment method: Place the above materials (inorganic skeleton fiber, organic tough fiber, substrate material) in a plasma cleaner at a mass of 3g or an area of ​​0.01 m2, introduce air or oxygen, and treat for 3-5 minutes at a power of 300-500 W.

[0028] Results: After the above treatment, the contact angle between the activated inorganic skeleton fiber, the activated organic tough fiber, and the activated matrix material and the surface of the activated matrix material and water was significantly reduced, and the characteristic peak of hydroxyl groups could be seen by Raman spectroscopy.

[0029] This step introduces a sufficient amount of active hydroxyl groups (-OH) onto the surface of the inert material to facilitate a condensation reaction with the silane coupling agent.

[0030] Step S103: Disperse the activated organic toughness fiber and the activated inorganic skeleton fiber in a mass ratio of 3:7-7:3 into the silanol hydrolysate to form a dilute solution with a mass concentration of 1%-5%, and stir at 40-60℃ for 1-2 hours to generate a slurry.

[0031] In the embodiments of this specification, the silanol is generated by the following method: adding 1.0%-3.0% of a silane coupling agent equivalent to the total mass of the fiber to deionized water; adjusting the pH of the solution to 3.5-5.5 with glacial acetic acid; and stirring for 30-60 minutes to allow the silane to be fully hydrolyzed to generate silanol. The silane coupling agent is determined based on the type of organic tough fiber. If the organic tough fiber is epoxy resin or phenolic resin fiber, the silane coupling agent is γ-glycidoxypropyltrimethoxysilane; if the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane; if the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0032] Through this step, one end of the silanol forms a strong hydrogen bond adsorption with the -OH group on the surface of the inorganic fiber, while the Y group (organic reaction end) undergoes preliminary chemical adsorption or entanglement with the functional groups (such as oxidized carboxyl groups, grafted epoxy groups, hydroxyl groups, etc.) on the surface of the organic fiber.

[0033] Step S105: Dilute the slurry concentration with deionized water to a mass fraction of 0.01%-0.05%, add a dispersant with a mass fraction of 0.05%-0.1% of the total fiber mass, and then flow it at high speed on a forming mesh at an inclination angle of 15-30 degrees and vacuum dewater it. By adjusting the fiber aspect ratio, the slurry concentration on the forming mesh, and the vacuum box suction, the porosity of the wet fiber web is precisely controlled at 60%-85%. After the wet fiber web leaves the forming mesh, it is transferred by a vacuum suction roller and directly covers the surface of the activated substrate material in an undried state to form a composite.

[0034] In the embodiments of this specification, the dispersant is one or more of polyacrylamide, polyethylene oxide, carboxymethyl cellulose, or hydroxypropyl methyl cellulose.

[0035] In the embodiments of this specification, the aspect ratio of the adjusting fiber is 3-6 mm, the slurry concentration is 0.01 wt% - 0.05 wt%, and the vacuum box suction is 1-5 kPa in the wet section and 10-35 kPa in the forming section.

[0036] The composite is passed through a low-pressure press roller, with the linear pressure controlled at 5-20 kN / m (or surface pressure <0.5MPa). Utilizing the surface tension and capillary action of a small amount of residual water, interlayer air bubbles are eliminated, allowing the wet fiber layer to adhere tightly to the substrate while preventing the porous skeleton from being crushed.

[0037] Step S107: The composite is kept at 100°C for 1-10 hours and then in-situ hot-pressed and anchored to form the inorganic-organic composite fiber layer.

[0038] In this step, under high temperature and dehydration conditions, the incompletely reacted silanol end of the coupling agent undergoes a complete dehydration condensation reaction with the -OH groups on the inorganic fiber and substrate surface to form Si-OM covalent bonds; simultaneously, the organic functional group end (Y) completes chemical cross-linking with the organic groups on the surface of the organic fiber or substrate. Ultimately, irreversible strong chemical bonding is achieved between the inorganic skeleton fiber, the organic toughening fiber, and the substrate material.

[0039] The covalent bonds constructed in the embodiments of this specification have a bond energy much higher than that of physical adhesion, enabling them to withstand the interfacial shear forces caused by sodium metal deposition in a system without a negative electrode, ensuring no peeling or powder shedding during cycling. Simultaneously, they exhibit a gradient ion damping effect; the porous structure in the fiber layer provides a "pre-growth space" for sodium metal, while the silane molecules distributed on the fiber surface have a high sodium affinity, reducing the desolvation barrier of sodium ions and guiding them to spread laterally in three-dimensional space rather than vertically penetrating.

[0040] The inorganic-organic composite fiber layer preparation method provided in the embodiments of this specification yields the following: Figure 2 , Figure 3 The inorganic-organic composite fiber layer structure shown.

[0041] The inorganic-organic composite fiber layer provided in the embodiments of this specification has extremely high interfacial bonding strength, solving the industry pain point of easy powder shedding in ceramic coatings. Experiments have shown that its peel strength is 3-5 times higher than that of traditional physical coatings. The inorganic skeleton fiber provides rigid puncture resistance, while the organic fiber ensures tensile strength and good preparation ability, with a good balance between mechanical toughness and strength. It has optimized sodium deposition kinetics, which reduces sodium deposition overpotential through polar fiber network and abundant sodium-loving sites, while achieving a high coulombic efficiency of over 99.9% and long cycle performance in a negative electrode-free system. It adopts low-cost wet web forming technology, and the equipment is compatible with the paper industry, making it easy to mass-produce and avoiding expensive processes such as magnetron sputtering.

[0042] This specification also provides an application of an inorganic-organic composite fiber layer in a negative electrode-free sodium-ion battery. This composite structure serves to provide pre-growth space for sodium deposition, suppress dendrite growth, and act as a current collector reinforcement layer in the negative electrode-free sodium-ion battery.

[0043] The inorganic-organic composite fiber layer provided in the embodiments of this specification has extremely high interfacial bonding strength, solving the industry pain point of easy powder shedding in ceramic coatings. Experiments have shown that its peel strength is 3-5 times higher than that of traditional physical coatings. The inorganic skeleton fiber provides rigid puncture resistance, while the organic fiber ensures tensile strength and good preparation ability, with a good balance between mechanical toughness and strength. It has optimized sodium deposition kinetics, which reduces sodium deposition overpotential through polar fiber network and abundant sodium-loving sites, while achieving a high coulombic efficiency of over 99.9% and long cycle performance in a negative electrode-free system. It adopts low-cost wet web forming technology, and the equipment is compatible with the paper industry, making it easy to mass-produce and avoiding expensive processes such as magnetron sputtering.

[0044] The above content details an inorganic-organic composite fiber layer and a method for preparing the inorganic-organic composite fiber layer. Correspondingly, this specification also provides an application of the inorganic-organic composite fiber layer, which is applied to a negative electrode-free sodium-ion battery.

[0045] To further verify the application of the inorganic-organic composite fiber layer provided in the embodiments of this specification, the following will describe it in conjunction with specific embodiments.

[0046] Example 1: form Figure 2 After the structure is completed, it can be directly used as the negative electrode current collector in a sodium-ion battery without a negative electrode.

[0047] Substrate: 12μm thick, carbon-coated aluminum foil.

[0048] formula: Inorganic fibers: E-glass fiber (0.6μm in diameter, 4mm in length), accounting for 60%.

[0049] Organic fibers: polyethylene terephthalate fibers (1.2 μm in diameter and 3 mm in length), accounting for 38%.

[0050] Coupling agent: KH-550 (γ-aminopropyltriethoxysilane), 2%.

[0051] Other: Dispersant PEO, the balance being pH adjusting agent.

[0052] Specific process parameters: Surface activation: Carbon-coated aluminum foil was treated with 300W oxygen plasma for 180 seconds. The E-glass fiber Raman spectra before and after activation are as follows: Figure 4 As shown, a distinct hydroxyl peak appears.

[0053] Internet concentration: 0.025wt%.

[0054] Vacuum suction: 3 kPa for wet section, 30 kPa for forming section.

[0055] Heat anchoring: Bake at 120℃ for 8 hours.

[0056] Test results are as follows Figure 5 As shown in the test results, we can see that: Functional layer thickness: 10 μm; Peel strength (180°): 75 N / m; Half-cell performance: at 5 mA / cm 2 1.5 mAh / cm 2 Under this system, the sodium nucleation overpotential is as low as 4 mV, the first-cycle coulombic efficiency is 99.2%, the average coulombic efficiency is 99.91%, and the system can be stably cycled for 300 cycles. Full cell performance: NFPP / / Al@C@Composite cell at 1.5 mA / cm² 2 1.5 mAh / cm 2 Under this system, the Coulomb efficiency was 98.5% in the first week and the capacity retention rate was 99.1% after 339 cycles.

[0057] Example 2: Composite diaphragm form Figure 3 A composite membrane structure is used in sodium-ion batteries without a negative electrode.

[0058] Substrate: 7 μm PP membrane formula: Inorganic fibers: E-glass fiber (0.6μm in diameter, 4mm in length), accounting for 60%.

[0059] Organic fibers: polyethylene terephthalate fibers (diameter 1.2μm, length 3mm), accounting for 38%.

[0060] Coupling agent: KH-550 (γ-aminopropyltriethoxysilane), 2%.

[0061] Other: Dispersant PEO, the balance being pH adjusting agent.

[0062] Specific process parameters: Surface activation: The diaphragm was placed in 30% hydrogen peroxide and sonicated at 40°C for 30 minutes.

[0063] Internet concentration: 0.03wt%.

[0064] Heat anchoring: Hot-press at 100°C for 1 hour.

[0065] Test results are as follows Figure 6 As shown in the test results, we can see that: Total thickness after composite: 17μm.

[0066] Heat shrinkage rate (150℃, 30min): <1.5%.

[0067] Half-cell performance: at 5 mA / cm², 1.5 mAh / cm² 2 Under this system, the sodium nucleation overpotential is as low as 4 mV, the first-cycle coulombic efficiency is 99.2%, the average coulombic efficiency is 99.91%, and the system can be stably cycled for 300 cycles.

[0068] Full-cell performance: NFPP / / PP@Composite / / Al@C battery at 1.5 mA / cm² 2 1.5 mAh / cm 2 Under this system, the Coulomb efficiency was 94.5% in the first week and the capacity retention rate was 96.3% after 408 cycles.

[0069] Comparative Example 1: Ordinary carbon-coated aluminum foil is used directly as the negative electrode current collector in a non-negative electrode sodium battery.

[0070] Substrate: 12μm thick, carbon-coated aluminum foil.

[0071] Test results are as follows Figure 7 As shown in the test results, we can see that: Peel strength (180°): 12 N / m Half-cell performance: at 5 mA / cm 2 1.5 mAh / cm 2 Under the given conditions, the sodium nucleation overpotential was 35 mV, the coulombic efficiency was 96.7% in the first cycle, and the average coulombic efficiency was 99.35% after 45 cycles, followed by significant fluctuations in coulombic efficiency.

[0072] Full cell performance: NFPP / / Al@C cell at 1.5 mA / cm² 2 1.5 mAh / cm 2 Under this system, the Coulomb efficiency was 84.5% in the first week and the capacity retention rate was 90.0% after 100 cycles.

[0073] The test results of Examples 1, 2 and Comparative Example 1 show that the inorganic-organic composite fiber layer provided in the examples of this specification significantly improves both the half-cell performance and the full-cell performance of the sodium-free battery.

[0074] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0075] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0076] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0077] The above description is merely an embodiment of this specification and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. An inorganic-organic composite fiber layer, characterized in that, The inorganic-organic composite fiber layer consists of 40%-70% inorganic skeleton fibers, 20%-50% organic tough fibers, and 1%-10% interface anchoring system by mass percentage. in, The inorganic skeleton fiber is one or more of glass fiber, alumina fiber or ceramic fiber; The organic tough fiber is one or more of polyethylene fiber, polypropylene fiber, polystyrene fiber, polyacrylonitrile fiber, polyimide fiber, polyethylene terephthalate fiber, epoxy resin fiber or phenolic resin fiber. The interface anchoring system includes a coupling agent and a pH adjuster, and is used to anchor the inorganic fiber skeleton and the organic tough fiber to the surface of the substrate material.

2. The inorganic-organic composite fiber layer as described in claim 1, characterized in that, The ceramic fiber is Na-β-Al2O3 ceramic fiber and / or NZSP ceramic fiber, wherein the NZSP ceramic fiber is , 0≤x≤3.

3. The inorganic-organic composite fiber layer as described in claim 1, characterized in that, The coupling agent is a silane coupling agent or a titanate / zirconate coupling agent, and the pH adjuster is glacial acetic acid.

4. The inorganic-organic composite fiber layer as described in claim 3, characterized in that, The X group of the silane coupling agent is methoxy or ethoxy, and the Y group of the silane coupling agent is determined according to the type of organic tough fiber. If the organic tough fiber is epoxy resin or phenolic resin fiber, then the silane coupling agent is γ-glycidoxypropyltrimethoxysilane. If the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, then the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane. If the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, then the silane coupling agent is γ-aminopropyltriethoxysilane.

5. The inorganic-organic composite fiber layer as described in claim 1, characterized in that, The substrate material is a current collector or a diaphragm; The current collector is aluminum foil, carbon-coated aluminum foil, copper foil, or carbon-coated copper foil; The diaphragm is a single-layer or multi-layer composite microporous membrane of polypropylene or polyethylene.

6. A method for preparing an inorganic-organic composite fiber layer, characterized in that, The preparation method is used to prepare the inorganic-organic composite fiber layer according to claim 1, and the preparation method includes: The inorganic skeleton fiber, organic tough fiber and substrate material are surface activated by chemical oxidation or plasma treatment to obtain activated inorganic skeleton fiber, activated organic tough fiber and activated substrate material. The activated organic tough fibers and the activated inorganic skeleton fibers are dispersed in a silanol hydrolysate at a mass ratio of 3:7-7:3 to form a dilute solution with a mass concentration of 1%-5%. The solution is stirred at 40-60°C for 1-2 hours to generate a slurry. The slurry concentration is diluted with deionized water to a mass fraction of 0.01%-0.05%. After adding a dispersant with a mass fraction of 0.05%-0.1% of the total fiber mass, the slurry is flowed at high speed on a forming mesh at an inclination angle of 15-30 degrees and vacuum dewatered. By adjusting the fiber aspect ratio, the slurry concentration on the forming mesh, and the vacuum box suction, the porosity of the wet fiber web is precisely controlled at 60%-85%. After the wet fiber web leaves the forming mesh, it is transferred by a vacuum suction roller and directly covers the surface of the activated substrate material in an undried state to form a composite. The composite is kept at 100°C for 1-10 hours and then in-situ hot-pressed and anchored to form the inorganic-organic composite fiber layer.

7. The preparation method according to claim 6, characterized in that, The silanol is generated by the following method: adding 1.0%-3.0% of a silane coupling agent equivalent to the total mass of the fiber to deionized water; adjusting the pH of the solution to 3.5-5.5 with glacial acetic acid; and stirring for 30-60 minutes to allow the silane to be fully hydrolyzed to generate silanol. The silane coupling agent is determined based on the type of organic tough fiber. If the organic tough fiber is epoxy resin or phenolic resin fiber, the silane coupling agent is γ-glycidoxypropyltrimethoxysilane; if the organic tough fiber is polyethylene, polypropylene, or polystyrene fiber, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane; if the organic tough fiber is polyimide, polyacrylonitrile, or polyethylene terephthalate fiber, the silane coupling agent is γ-aminopropyltriethoxysilane.

8. The preparation method according to claim 6, characterized in that, The dispersant is one or more of polyacrylamide, polyethylene oxide, carboxymethyl cellulose, or hydroxypropyl methyl cellulose.

9. The preparation method according to claim 6, characterized in that, The aspect ratio of the regulating fiber is 3-6 mm, the online concentration of the slurry is 0.01 wt% - 0.05 wt%, and the suction force of the vacuum box is 1-5 kPa in the wet section and 10-35 kPa in the forming section.

10. An application of an inorganic-organic composite fiber layer, characterized in that, The inorganic-organic composite fiber layer is used in a negative electrode-free sodium-ion battery.

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