A composite lithium supplementing diaphragm, a preparation method thereof and a lithium ion battery

Abstract

The application provides a composite lithium supplementing diaphragm, a preparation method thereof and a lithium ion battery, and relates to the technical field of lithium ion batteries. The lithium supplementing process of the electrode is realized through the lithiumated organic particles in the composite lithium supplementing diaphragm. The performance of the lithium ion battery is improved, the first charge-discharge efficiency and the cycle life of the lithium ion battery are improved, and the high capacity of the lithium ion battery is ensured. The electrode lithium supplementing process is completed without using high-cost lithium supplementing agents, the electrode lithium supplementing cost of the lithium ion battery is effectively reduced, the composite lithium supplementing diaphragm has a simple structure, and the thermal performance and the mechanical performance of the base film layer are not deteriorated, so that the preparation of the lithium supplementing functional coating can be carried out on the base film layer with different thicknesses and different materials according to the demand, the thickness of the base film layer is adjusted to realize the ultra-thin composite lithium supplementing diaphragm, the lithium supplementing demand of the electrode with different materials is met, the product diversification is realized, and the large-scale production demand is more suitable.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery technology, and more specifically, to a composite lithium-replenishing separator, its preparation method, and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries, with their advantages of high voltage, high energy density, and long cycle life, have become one of the most widely used rechargeable batteries. However, with the miniaturization and extended standby time of portable electronic devices, as well as the adoption of high-power, high-energy devices such as electric bicycles and electric vehicles, increasingly higher demands are being placed on the energy density of lithium-ion batteries as energy storage power sources. For lithium-ion batteries, the formation of a solid electrolyte interface (SEI) film during the first charge consumes active lithium in the electrodes, resulting in a decrease in the first charge-discharge efficiency. Furthermore, the loss of active lithium leads to a reduction in the battery's capacity. Therefore, improving lithium replenishment capabilities for lithium-ion batteries is a major research focus for researchers today. Summary of the Invention

[0003] In view of this, this application provides a composite lithium-replenishing separator, its preparation method, and a lithium-ion battery, effectively solving the technical problems existing in the prior art and achieving the purpose of lithium replenishment to the electrodes of lithium-ion batteries. This not only improves the performance of lithium-ion batteries but also increases the initial charge-discharge efficiency and cycle life, ensuring the high capacity of lithium-ion batteries. Furthermore, since it eliminates the need for high-cost lithium replenishing agents to replenish the electrodes, it reduces the cost of electrode lithium replenishment for lithium-ion batteries.

[0004] To achieve the above objectives, the technical solution provided in this application is as follows:

[0005] A composite lithium-supplementing separator, the composite lithium-supplementing separator comprising:

[0006] Base film layer;

[0007] And a lithium replenishing functional coating located on at least one side surface of the base film layer, wherein the lithium replenishing functional coating comprises lithium-ionized organic particles.

[0008] Optionally, at least one of the lithium replenishing functional coatings includes a lithium-ion organic particle coating, wherein the lithium-ion organic particle coating includes the lithium-ion organic particles.

[0009] Alternatively, at least one of the lithium replenishing coatings may further include inorganic particles;

[0010] Alternatively, the composite lithium replenishing membrane includes two lithium replenishing functional coatings located on opposite sides of the base film layer, one of the lithium replenishing functional coatings including the lithium-ion organic particle coating, and the other lithium replenishing functional coating including inorganic particles.

[0011] Optionally, the D50 particle size of the lithium-ionized organic particles satisfies: 50nm < D50 < 1000nm;

[0012] The thickness h1 of the lithium-ion organic particle coating satisfies: h1≤0.8×h2, where h2 is the thickness of the base film layer;

[0013] Furthermore, the coverage of the lithium-ion organic particle coating is 3% to 40%.

[0014] Optionally, the lithium-supplementing coating including the inorganic particles includes:

[0015] An inorganic particle coating located on the surface of the base film layer, wherein the inorganic particle coating includes the inorganic particles;

[0016] And, a lithium-ionized organic particle coating located on the side of the inorganic particle coating opposite to the base film layer, wherein the lithium-ionized organic particle coating includes the lithium-ionized organic particles.

[0017] Optionally, the D50 particle size of the lithium-ion organic particles satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles;

[0018] The thickness h3 of the lithium replenishment coating satisfies: h3≤h2, where h2 is the thickness of the base film layer;

[0019] Furthermore, the thickness of the base film layer ranges from 3 to 30 μm.

[0020] Optionally, the lithium-replenishing coating including the inorganic particles may be a mixed coating of the lithium-ionized organic particles and the inorganic particles.

[0021] Optionally, the D50 particle size of the lithium-ion organic particles satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles;

[0022] The thickness h3 of the lithium replenishment coating satisfies: h3≤h2, where h2 is the thickness of the base film layer;

[0023] Furthermore, the mass percentage of the lithium-ionized organic particles in the lithium replenishment functional coating ranges from 5% to 20%.

[0024] Optionally, the base film layer includes: a polyethylene base film layer, or a polypropylene base film layer, or a nonwoven base film layer, or an aramid base film layer.

[0025] Optionally, the lithium-ion organic material of the lithium-ion organic particles includes at least one of lithium-ion carboxymethyl cellulose, lithium-ion polyacrylic acid, lithium-ion styrene-butadiene rubber, and lithium-ion polyvinylidene fluoride.

[0026] Optionally, the inorganic material of the inorganic particles includes at least one of the following: aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride, and inorganic ceramic solid electrolytes.

[0027] Optionally, the inorganic ceramic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus sulfide, lithium phosphorus sulfide chloride, and lithium germanium aluminum phosphate.

[0028] Based on the same inventive concept, this application also provides a method for preparing a composite lithium-supplementing separator, wherein the preparation method includes:

[0029] Provide a base film layer;

[0030] A lithium replenishing functional coating is formed on the surface of at least one side of the base film layer, wherein the lithium replenishing functional coating comprises lithium-ionized organic particles.

[0031] Optionally, the lithium-replenishing functional coating includes a lithium-based organic particle coating, wherein the preparation method of the lithium-replenishing functional coating includes:

[0032] A lithium-ionized organic material is mixed with water to obtain an organic mixed solution;

[0033] The organic mixed solution is sprayed onto the surface of the base film layer and then baked and dried to form the lithium replenishing functional coating.

[0034] Optionally, the lithium-replenishing functional coating includes an inorganic particle coating on the surface of the base film layer, and a lithium-modified organic particle coating on the side of the inorganic particle coating facing away from the base film layer, wherein the method for preparing the lithium-replenishing functional coating includes:

[0035] A method for preparing an aqueous inorganic slurry and an organic mixed solution is described, wherein the method for preparing the aqueous inorganic slurry includes: dissolving an additive in deionized water as a solvent, wherein the additive includes at least a thickener, a binder, and a wetting agent; adding an inorganic material to the solvent to obtain the aqueous inorganic slurry; and the method for preparing the organic mixed solution includes: mixing a lithium-ionized organic material with water to obtain the organic mixed solution.

[0036] The aqueous inorganic slurry is coated on the surface of the base film layer and preliminarily baked and dried to form a semi-finished composite lithium-supplementing separator;

[0037] The organic mixed solution is sprayed onto the surface of the semi-finished composite lithium-replenishing separator and then baked and dried to form the lithium-replenishing functional coating.

[0038] Optionally, the lithium-replenishing functional coating is a mixed coating of lithium-ion organic particles and inorganic particles, wherein the preparation method of the lithium-replenishing functional coating includes:

[0039] The additive is dissolved in deionized water to form a solvent, wherein the additive includes at least a thickener, a binder, and a wetting agent;

[0040] Inorganic materials and lithium-ionized organic materials are added to the dissolving solvent to obtain a mixed slurry;

[0041] The mixed slurry is coated onto the surface of the base film layer and then baked and dried to form the lithium replenishing functional coating.

[0042] Based on the same inventive concept, this application also provides a lithium-ion battery, the lithium-ion battery comprising:

[0043] The aforementioned composite lithium-replenishing separator is located between the positive and negative electrodes of the lithium-ion battery.

[0044] Optionally, the positive electrode material includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, spinel manganese oxide, lithium-rich manganese-based oxide, and lithium manganese iron phosphate.

[0045] Furthermore, the material of the negative electrode includes at least one of graphite, silicon carbide, silicon oxide, and a mixture of graphite and silicon.

[0046] Compared with existing technologies, the technical solution provided in this application has at least the following advantages:

[0047] This application provides a composite lithium-replenishing separator, its preparation method, and a lithium-ion battery. The composite lithium-replenishing separator includes: a base film layer; and a lithium-replenishing functional coating located on at least one side surface of the base film layer, wherein the lithium-replenishing functional coating includes lithium-modified organic particles. The technical solution provided in this application achieves lithium replenishment of the electrodes of a lithium-ion battery through the lithium-modified organic particles in the composite lithium-replenishing separator. This not only improves the performance of the lithium-ion battery but also increases the initial charge-discharge efficiency and cycle life, ensuring the high capacity of the lithium-ion battery. Since lithium replenishment of the electrodes can be achieved through the lithium-replenishing functional coating, the technical solution provided in this application eliminates the need for high-cost lithium-replenishing agents, effectively reducing the cost of electrode lithium replenishment for lithium-ion batteries.

[0048] Furthermore, the composite lithium replenishment membrane only needs to prepare a lithium replenishment functional coating on the surface of the base film layer to achieve the lithium replenishment function. It is not only simple in structure, but also does not deteriorate the thermal and mechanical properties of the base film layer itself. Therefore, the lithium replenishment functional coating can be prepared on the base film layer with different thicknesses and materials according to the requirements. By adjusting the thickness of the base film layer, an ultra-thin composite lithium replenishment membrane can be achieved, thereby meeting the lithium replenishment requirements of electrodes with different materials, realizing product diversification, and making it more suitable for large-scale production needs. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the structure of a composite lithium-supplementing separator provided in an embodiment of this application;

[0051] Figure 2 This is a schematic diagram of another composite lithium-supplementing separator provided in an embodiment of this application;

[0052] Figure 3 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0053] Figure 4 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0054] Figure 5 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0055] Figure 6This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0056] Figure 7 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0057] Figure 8 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0058] Figure 9 This is a schematic diagram of the structure of another composite lithium-supplementing separator provided in the embodiments of this application;

[0059] Figure 10 A flowchart illustrating a method for preparing a composite lithium-supplementing separator, as provided in an embodiment of this application;

[0060] Figure 11 This is a schematic diagram of the structure of a lithium-ion battery provided in an embodiment of this application.

[0061] Figure label:

[0062] 10-Composite lithium-supplementing separator; 100-Base film layer; 21-Positive electrode; 22-Negative electrode; 200-Lithium-supplementing functional coating; 201-Lithium-modified organic particles; 202-Inorganic particles; 210-Lithium-modified organic particle coating; 220-Mixed coating; 221-Inorganic particle sub-coating; 222-Lithium-modified organic particle sub-coating. Detailed Implementation

[0063] The technical solutions of the embodiments of this application 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 application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] As described in the background section, lithium-ion batteries have become one of the most widely used rechargeable batteries due to their advantages of high voltage, high energy density, and long cycle life. However, with the miniaturization and extended standby time of portable electronic devices, as well as the adoption of high-power, high-energy devices such as electric bicycles and electric vehicles, increasingly higher demands are being placed on the energy density of lithium-ion batteries as energy storage power sources. For lithium-ion batteries, the formation of a solid electrolyte interface film during the first charge consumes active lithium in the electrodes, resulting in a decrease in the initial charge-discharge efficiency. Furthermore, the loss of active lithium in the battery leads to a decrease in capacity. Therefore, improving the lithium replenishment function of lithium-ion batteries is a major research focus for researchers today.

[0065] Current technologies generally involve directly sprinkling lithium powder onto a separator and then cold-pressing it to form a composite separator, or preparing lithium powder into a slurry and coating it onto the separator surface, or combining lithium strips and the separator by cold pressing, or combining molten lithium with the separator. These methods have the following drawbacks: First, current lithium strip composite technology makes it difficult to precisely control the content of metallic lithium composited on the separator. Lithium metal is often in excess; some lithium is used for supplemental lithium production, while the excess lithium acts as nucleation sites for lithium ions, leading to lithium deposition and the formation of lithium dendrites. Second, while sprinkling metallic lithium powder onto the separator surface and then cold-pressing can also produce composite separators, the large specific surface area and high activity of lithium powder require a dry environment, making the entire process extremely demanding. Third, although preparing a slurry from lithium powder allows for control of the amount of metallic lithium added, the process requires mixing the slurry with organic solvents, followed by coating and drying. The process is complicated and the extensive use of organic solvents is not environmentally friendly. In addition, the coating thickness cannot be controlled, and the liquid slurry can easily clog the microporous structure of the separator, resulting in high impedance of the lithium-ion battery. Fourth, the ultra-thin lithium strip is formed by melting lithium ingots and coating them on the surface of a pre-cooled separator, and then cooling the separator to solidify the lithium metal. The disadvantage is that the pore-closing temperature of the separator itself is 130℃-150℃, while the melting point of lithium metal is 180℃. Although the separator is pre-cooled by surface area, the instantaneous temperature of the separator surface when it comes into contact with the molten lithium metal will also reach 180℃, causing the separator to close pores and making the assembled lithium-ion battery unusable. These are all problems with the current technology.

[0066] Based on this, the embodiments of this application provide a composite lithium-replenishing separator, its preparation method, and a lithium-ion battery, effectively solving the technical problems existing in the prior art, achieving the purpose of lithium replenishment to the electrodes of lithium-ion batteries, improving the performance of lithium-ion batteries, increasing the first charge-discharge efficiency and cycle life of lithium-ion batteries, and ensuring the high capacity of lithium-ion batteries. Since it eliminates the need to use high-cost lithium replenishing agents to replenish the electrodes, it also reduces the cost of electrode lithium replenishment for lithium-ion batteries.

[0067] To achieve the above objectives, the technical solutions provided in this application are as follows, in specific combination with... Figures 1 to 11 The technical solutions provided in the embodiments of this application will be described in detail.

[0068] refer to Figure 1The diagram shown is a structural schematic of a composite lithium-replenishing separator provided in an embodiment of this application. The composite lithium-replenishing separator includes: a base film layer 100; and a lithium-replenishing functional coating 200 located on at least one surface of the base film layer 100, wherein the lithium-replenishing functional coating 200 includes lithium-modified organic particles 201. It is understood that the lithium-replenishing functional coating 200 can be formed on at least one of the two opposing surfaces of the base film layer 100 provided in this application. The lithium-modified organic particles 201 in the composite lithium-replenishing separator achieve the purpose of lithium replenishment to the electrodes of the lithium-ion battery. This not only improves the performance of the lithium-ion battery but also increases the initial charge-discharge efficiency and cycle life, ensuring the high capacity of the lithium-ion battery. Since lithium replenishment to the electrodes can be achieved through the lithium-replenishing functional coating 200, the technical solution provided in this application can complete the electrode lithium replenishment process without using high-cost lithium replenishing agents, effectively reducing the electrode lithium replenishment cost of lithium-ion batteries. Furthermore, the composite lithium replenishment membrane only needs to prepare a lithium replenishment functional coating 200 on the surface of the base film layer 100 to achieve the lithium replenishment function. Not only is the structure simple, but it also does not deteriorate the thermal and mechanical properties of the base film layer 100 itself. Therefore, the lithium replenishment functional coating can be prepared on the base film layer 100 with different thicknesses and materials according to the requirements. By adjusting the thickness of the base film layer 100, an ultra-thin composite lithium replenishment membrane can be achieved, thereby meeting the lithium replenishment requirements of electrodes with different materials, realizing product diversification, and making it more suitable for large-scale production needs.

[0069] In some embodiments, at least one of the lithium-replenishing functional coatings 200 provided in this application includes a lithium-ion organic particle coating 210, wherein the lithium-ion organic particle coating 210 includes the lithium-ion organic particles 201. Continuing as... Figure 1 As shown, the composite lithium-replenishing separator provided in this embodiment may include only one lithium-replenishing functional coating 200, which is preferably located on the surface of the base film layer 100 facing the positive electrode of the lithium-ion battery. The lithium-replenishing functional coating 200 is implemented by a lithium-ion organic particle coating 210, and the lithium-ion organic particle coating 210 includes lithium-ion organic particles 201, thereby achieving the lithium-replenishing function of the electrode through the lithium-ion organic particles 201. Alternatively, refer to... Figure 2The diagram shown is a schematic diagram of another composite lithium replenishing membrane provided in this application embodiment. The composite lithium replenishing membrane provided in this application embodiment includes two lithium replenishing functional coatings 200, which are respectively located on two opposite surfaces of the base film layer 100. Each lithium replenishing functional coating 200 is implemented by a lithium-ion organic particle coating 210, and the lithium-ion organic particle coating 210 includes lithium-ion organic particles 201. By forming lithium-ion organic particle coatings 210 on both surfaces of the base film layer 100, the lithium replenishing effect of the composite lithium replenishing membrane on the electrode is further improved.

[0070] The lithium-replenishing functional coating 200 provided in this application embodiment can be further optimized to improve the performance of the composite lithium-replenishing separator. In some embodiments, the lithium-replenishing functional coating 200 provided in this application embodiment can also contain some inorganic materials to improve the heat resistance and other properties of the composite lithium-replenishing separator, thereby increasing the service life of the lithium-ion battery. See details... Figure 3 The diagram shown is a structural schematic of another composite lithium replenishing membrane provided in this application embodiment. In this application embodiment, at least one of the lithium replenishing functional coatings 200 also includes inorganic particles 202, which improves the heat resistance of the composite lithium replenishing membrane and further improves the performance of the composite lithium replenishing membrane while ensuring lithium replenishment of the electrode.

[0071] Figure 3 This illustration shows a composite lithium-replenishing separator comprising only one lithium-replenishing functional coating 200, where the lithium-replenishing functional coating 200 includes both lithium-bearing organic particles 201 and inorganic particles 202. Optionally, when the composite lithium-replenishing separator comprises only one lithium-replenishing functional coating 200, this lithium-replenishing functional coating 200 can be located on the surface of the base film layer 100 facing the positive electrode. Figure 4 The diagram shown is a structural schematic of another composite lithium replenishing membrane provided in this application embodiment. When the composite lithium replenishing membrane provided in this application embodiment includes two lithium replenishing functional coatings 200 respectively located on two opposite surfaces of the base film layer 100, the two lithium replenishing functional coatings 200 are respectively located on two opposite surfaces of the base film layer 100. Each lithium replenishing functional coating 200 includes organic particles 201 and inorganic particles 202, which further improves the lithium replenishing effect of the composite lithium replenishing membrane on the electrode, and also further improves the heat resistance of the composite lithium replenishing membrane.

[0072] Or refer to Figure 5The diagram shown illustrates the structure of another composite lithium-replenishing separator provided in this application embodiment. The composite lithium-replenishing separator provided in this application embodiment includes two lithium-replenishing functional coatings 200 located on opposite surfaces of the base film layer 100. One lithium-replenishing functional coating 200 includes a lithium-ion organic particle coating 210, and the other lithium-replenishing functional coating 200 also includes inorganic particles 202. In other words, when the composite lithium-replenishing separator provided in this application embodiment includes two lithium-replenishing functional coatings 200 located on opposite surfaces of the base film layer 100, one lithium-replenishing functional coating 200 may only include lithium-ion organic particles 201, and the other lithium-replenishing functional coating 200 may include both lithium-ion organic particles 201 and inorganic particles 202, thereby achieving diversity in the composite lithium-replenishing separator and improving its applicability.

[0073] In some embodiments, when the lithium-replenishing coating 200 provided in this application includes inorganic particles 202, the coating containing the inorganic particles 202 and the coating containing the lithium-ionized organic particles 201 can be layered. Continuing as... Figures 3 to 5 As shown, the lithium-supplementing functional coating 200 provided in this application embodiment, including the inorganic particles 202, comprises: an inorganic particle sub-coating 221 located on the surface of the base film layer 100, wherein the inorganic particle coating 221 includes the inorganic particles 202; and a lithium-modified organic particle coating 222 located on the side of the inorganic particle coating 221 facing away from the base film layer, wherein the lithium-modified organic particle coating 222 includes lithium-modified organic particles 201. This application embodiment employs a layered design of the inorganic particle coating 221 and the lithium-modified organic particle coating 222, which improves the heat resistance of the composite lithium-supplementing separator, enhances its air permeability, and reduces its impedance.

[0074] In some embodiments, when the lithium-supplementing functional coating 200 provided in this application includes inorganic particles 202, the inorganic particles 202 and lithium-ionized organic particles 201 can also be mixed to form a hybrid coating. See details. Figure 6 The diagram shown is a structural schematic of another composite lithium replenishing membrane provided in this application embodiment. In this application embodiment, the lithium replenishing functional coating 200 including the inorganic particles 202 is a mixed coating 220 of the lithium-ionized organic particles 201 and the inorganic particles 202. It enhances the adhesion between the composite lithium replenishing membrane and the electrode while improving the heat resistance of the composite lithium replenishing membrane.

[0075] Figure 6This illustration depicts a composite lithium-replenishing separator comprising only one lithium-replenishing functional coating 200, where the lithium-replenishing functional coating 200 is a mixed coating 220 of lithium-bearing organic particles 201 and inorganic particles 202. Optionally, when the composite lithium-replenishing separator comprises only one lithium-replenishing functional coating 200, this mixed coating 220 may be located on the surface of the base film layer 100 facing the positive electrode. Or refer to... Figure 7 The diagram shown is a structural schematic of another composite lithium-replenishing separator provided in this application embodiment. When the composite lithium-replenishing separator provided in this application embodiment includes two lithium-replenishing functional coatings 200 respectively located on two opposite surfaces of the base film layer 100, both lithium-replenishing functional coatings 200 can be a mixed coating 220 of lithium-bearing organic particles 201 and inorganic particles 202, further improving the lithium-replenishing effect of the composite lithium-replenishing separator on the electrode and improving the heat resistance of the composite lithium-replenishing separator. Alternatively, refer to... Figure 8 The diagram shown is a structural schematic of another composite lithium-replenishing separator provided in this application embodiment. When the composite lithium-replenishing separator provided in this application embodiment includes two lithium-replenishing functional coatings 200 located on opposite surfaces of the base film layer 100, and both lithium-replenishing functional coatings 200 include inorganic particles 202, one lithium-replenishing functional coating 200 is a mixed coating 220 of lithium-bearing organic particles 201 and inorganic particles 202, while the other lithium-replenishing functional coating 200 is a layered structure of inorganic particle sub-coating 221 and lithium-bearing organic particle coating 222. Alternatively, refer to... Figure 9 The diagram shown is a structural schematic of another composite lithium replenishing membrane provided in this application embodiment. In this embodiment, the composite lithium replenishing membrane includes two lithium replenishing functional coatings 200 located on opposite surfaces of the base film layer 100. One lithium replenishing functional coating 200 includes a lithium-ion organic particle coating 210, while the other lithium replenishing functional coating 200 includes inorganic particles 202. The lithium replenishing functional coating 200 including inorganic particles 202 can be a mixed coating 220 of lithium-ion organic particles 201 and inorganic particles 202, thereby achieving diversity in the composite lithium replenishing membrane and improving its applicability.

[0076] This application embodiment can also limit parameters such as particle size and film thickness to ensure that the performance of the composite lithium-supplementing separator reaches its optimal level. Specifically, when the lithium-supplementing functional coating 200 provided in this application embodiment includes a lithium-ion organic particle coating 210, that is, when only a coating including lithium-ion organic particles 201 is provided on one surface of the base film layer 100, in the lithium-ion organic particle coating 210: the D50 particle size of the lithium-ion organic particles 201 satisfies: 50nm < D50 < 1000nm; the thickness h1 of the lithium-ion organic particle coating 210 satisfies: h1 ≤ 0.8 × h2, where h2 is the thickness of the base film layer 100; and the coverage of the lithium-ion organic particle coating 210 is 3% to 40%.

[0077] Furthermore, when the lithium replenishment functional coating 200 includes lithium-ion organic particles 201 and inorganic particles 202, and is designed in layers as inorganic particle sub-coating 221 and lithium-ion organic particle sub-coating 222, the D50 particle size of the lithium-ion organic particles 201 provided in this application embodiment satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles 202; the thickness h3 of the lithium replenishment functional coating 200 satisfies: h3 ≤ h2, where h2 is the thickness of the base film layer 100; and the thickness range of the base film layer 100 is 3 to 30 μm.

[0078] Furthermore, when the lithium-supplementing functional coating 200 includes lithium-ion organic particles 201 and inorganic particles 202, and the lithium-ion organic particles 201 and inorganic particles 202 are prepared as a mixed coating 220, in the mixed coating 220 provided in this application embodiment: the D50 particle size of the lithium-ion organic particles 201 satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles 202; the thickness h3 of the lithium-supplementing functional coating 200 satisfies: h3 ≤ h2, where h2 is the thickness of the base film layer; and the mass percentage of the lithium-ion organic particles 201 in the lithium-supplementing functional coating 200 ranges from 5% to 20%.

[0079] In some embodiments, the base film layer 100 provided in this application includes: a polyethylene base film layer, or a polypropylene base film layer, or a nonwoven fabric base film layer, or an aramid base film layer. Furthermore, the lithium-ion organic material of the lithium-ion organic particles 201 provided in this application includes at least one of lithium-ion carboxymethyl cellulose, lithium-ion polyacrylic acid, lithium-ion styrene-butadiene rubber, and lithium-ion polyvinylidene fluoride. In addition, the inorganic material of the inorganic particles 202 provided in this application includes at least one of: aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride, and inorganic ceramic solid electrolytes. Optionally, the inorganic ceramic solid electrolyte provided in this application embodiment includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus sulfide, lithium phosphorus sulfide chloride, and lithium germanium aluminum phosphate, thereby accelerating lithium-ion transport and reducing the impedance of the composite lithium replenishment membrane.

[0080] The composite lithium-replenishing separator provided in this application and its effect in lithium-ion batteries will be described in more detail below with reference to several specific embodiments and comparative examples.

[0081] Example 1 of this application: The thickness of the base film layer 100 is 7 μm. A lithium-ion organic particle coating 210 is sprayed onto each of the two opposite surfaces of the base film layer 100. The organic material of the lithium-ion organic particles 201 is lithium-ion polyacrylic acid, the particle size of the lithium-ion organic particles 201 is 500 nm, the thickness of the lithium-ion organic particle coating 210 is 3 μm, and the coverage of the lithium-ion organic particle coating 210 is 30%.

[0082] Example 2 of this application: The thickness of the base film layer 100 is 7 μm. A lithium-ion organic particle coating 210 is sprayed onto one side of the base film layer 100. The organic material of the lithium-ion organic particles 201 is lithium-ion carboxymethyl cellulose, the particle size of the lithium-ion organic particles 201 is 400 nm, and the thickness of the lithium-ion organic particle coating 210 is 2 μm. A lithium-supplementing functional coating 200 consisting of an inorganic particle coating 221 and a lithium-ion organic particle coating 222 is coated onto the other side of the base film layer 100. The inorganic material of the inorganic particles 202 is alumina, the particle size of the inorganic particles 202 is 700 nm, and the thickness of the inorganic particle coating 221 is 2 μm; the organic material of the lithium-ion organic particles 201 is lithium-ion carboxymethyl cellulose, the thickness of the lithium-ion organic particle coating 222 is 2 μm, and the coverage of the lithium-ion organic particle coating 222 is 28%.

[0083] Example 3 of this application: The thickness of the base film layer 100 is 9 μm. Both opposite surfaces of the base film layer 100 are coated with a lithium-supplementing functional coating 200 consisting of an inorganic particle coating 221 and a lithium-ionized organic particle coating 222. The inorganic material of the inorganic particles 202 is silicon dioxide, the particle size of the inorganic particles 202 is 1000 nm, and the thickness of the inorganic particle coating 221 is 3 μm; the organic material of the lithium-ionized organic particles 201 is lithium-ionized styrene-butadiene rubber, the thickness of the lithium-ionized organic particle coating 222 is 3 μm, and the coverage of the lithium-ionized organic particle coating 222 is 25%.

[0084] Example 4 of this application: The thickness of the base film layer 100 is 9 μm. A mixed coating 220 of lithium-ion organic particles 201 and inorganic particles 202 is coated on both opposite surfaces of the base film layer 100. The inorganic material of the inorganic particles 202 is zirconium dioxide, and the particle size of the inorganic particles 202 is 800 nm. The thickness of the mixed coating 220 is 3 μm. The organic material of the lithium-ion organic particles 201 is lithium-ion polyvinylidene fluoride, and the particle size of the lithium-ion organic particles 201 is 300 nm. The mass percentage of the lithium-ion organic particles 201 is 15%.

[0085] Comparative Example 1: The thickness of the base film layer is 7 μm. An organic coating is sprayed onto both opposite surfaces of the base film layer. The organic particles in the organic coating are made of polyacrylic acid, the particle size of the organic particles is 500 nm, the thickness of the organic coating is 3 μm, and the coverage of the organic coating is 30%.

[0086] Comparative Example 2: The thickness of the base film layer is 7 μm. An organic coating is sprayed onto one side of the base film layer. The organic particles in the organic coating are carboxymethyl cellulose-based, with a particle size of 400 nm, and the organic coating thickness is 2 μm. The other side of the base film layer is coated in layers. First, an alumina coating is applied, with a particle size of 700 nm and a coating thickness of 2 μm. Then, a carboxymethyl cellulose-based coating is sprayed, with a thickness of 2 μm and a coverage of 28%.

[0087] Comparative Example 3: The thickness of the base film layer is 9 μm. The base film layer is coated in layers on both sides. First, a layer of silica is coated, with a particle size of 1000 nm and a thickness of 3 μm. Then, a layer of styrene-butadiene rubber (SBR) coating is sprayed, with a particle size of 300 nm and a thickness of 3 μm. The coverage of the SBR coating is 25%.

[0088] Comparative Example 4: The thickness of the base film layer is 9 μm. The two opposite surfaces of the base film layer are coated with a mixture of organic and inorganic particles. The organic material of the organic particles is polyvinylidene fluoride (PVDF), and the inorganic material of the inorganic particles is zirconium dioxide. The zirconium dioxide particles have a particle size of 800 nm. The coating thickness on any one side of the base film layer is 3 μm. The PVDF particles have a particle size of 300 nm, and the PVDF particles account for 15% of the total mass.

[0089] The separators provided in Examples 1 to 4 of this application and Comparative Examples 1 to 4 were subjected to heat shrinkage performance tests, puncture resistance tests, and separator impedance tests at 150°C for 30 minutes. They were then assembled into soft-pack batteries. The positive electrode of the battery was a nickel-cobalt-manganese ternary material, the negative electrode was artificial graphite material, and the electrolyte was 1M LiPF6 (lithium hexafluorophosphate):EC (ethylene carbonate):EMC (ethyl methyl carbonate):DMC (dimethyl carbonate) = 1:1:1 + 1%FEC (fluoroethylene carbonate) + 1%VC (ethylene carbonate). The battery capacity was 2Ah. The initial efficiency, fast charge cycle capability, and 60°C high-temperature full-charge storage capability of each sample were examined. The test data are shown in Tables 1 and 2 below. Table 1 is a comparison of the physical properties of the separators, and Table 2 is a comparison of the performance of the batteries composed of the separators.

[0090] category Puncture resistance gf Heat shrinkage capacity % at 150℃ / 30min Example 1 of this application 387 6.8% Comparative Example 1 385 7.5% Example 2 of this application 405 2.8% Comparative Example 2 398 2.2% Example 3 of this application 451 1.3% Comparative Example 3 446 1.5% Example 4 of this application 434 1.6% Comparative Example 4 435 1.8%

[0091] Table 1

[0092] category First-time efficiency 4C / 1C room temperature fast charging cycle retention rate (800 cycles) 90-day capacity retention rate after full-charge storage at 60℃ Example 1 of this application 88.75% 82.35% 85.23% Comparative Example 1 86.25% 79.56% 77.56% Example 2 of this application 89.12% 84.78% 87.38% Comparative Example 2 85.88% 80.15% 82.87% Example 3 of this application 88.85% 85.16% 88.98% Comparative Example 3 86.21% 81.32% 81.56% Example 4 of this application 89.25% 85.65% 87.67% Comparative Example 4 86.13% 80.23% 80.56%

[0093] Table 2

[0094] As can be seen from the test data in Tables 1 and 2 above, the composite lithium-replenishing separator prepared by the technical solution provided in this application embodiment does not deteriorate in physical properties. On the contrary, it improves properties such as heat resistance and puncture resistance, and greatly improves fast charging and high-temperature storage. It can further improve the performance of lithium-ion batteries and extend the service life of lithium-ion batteries.

[0095] Based on the same inventive concept, this application also provides a method for preparing a composite lithium-supplementing separator, used to prepare the composite lithium-supplementing separator provided in any of the above embodiments. (Reference) Figure 10 The diagram shown is a flowchart of a method for preparing a composite lithium-supplementing separator according to an embodiment of this application. The preparation method provided in this embodiment includes:

[0096] S1. Provide a base film layer.

[0097] S2. A lithium replenishing functional coating is formed on the surface of at least one side of the base film layer, wherein the lithium replenishing functional coating comprises lithium-ionized organic particles.

[0098] The following describes in detail the preparation process of several specific lithium-supplementing functional coatings 200 provided in the embodiments of this application, namely, the preparation process of the stacking of lithium-ion organic particle coating 210, inorganic particle coating 221 and lithium-ion organic particle coating 222, and the preparation process of the mixed coating 220. In some embodiments, the lithium-supplementing functional coating 200 provided in the embodiments of this application includes a lithium-ion organic particle coating 210, wherein the preparation method of the lithium-supplementing functional coating 200 (i.e., the lithium-ion organic particle coating 210) includes: mixing lithium-ion organic materials and water to obtain an organic mixed solution; spraying the organic mixed solution onto the surface of the base film layer 100, and baking and drying to form the lithium-supplementing functional coating 200. Specifically, the preparation method of the lithium-ion organic particle coating 210 provided in this application embodiment may include: adding lithium-ion organic material and water into a mixer and stirring for 30-120 minutes to fully dissolve the powder mixture to obtain an organic mixed solution; then spraying the organic mixed solution onto a set surface of the base film layer 100, and then drying it in an oven at 30-80°C for 10-30 minutes to obtain the lithium-ion organic particle coating 210.

[0099] In some embodiments, the lithium-supplementing functional coating 200 provided in this application includes an inorganic particle coating 221 located on the surface of the base film layer 100, and a lithium-modified organic particle coating 222 located on the side of the inorganic particle coating 221 facing away from the base film layer 100. The preparation method of the lithium-supplementing functional coating 200 includes: obtaining an aqueous inorganic slurry and an organic mixed solution. The preparation method of the aqueous inorganic slurry includes: dissolving an additive in deionized water as a solvent. The additives include at least thickeners, binders, and wetting agents; an inorganic material is added to the dissolving solvent to obtain an aqueous inorganic slurry; and the method for preparing the organic mixed solution includes: mixing a lithium-ionized organic material with water to obtain an organic mixed solution; then coating the aqueous inorganic slurry onto the surface of the base film layer 100 and pre-baking and drying it to form a semi-finished composite lithium-replenishing separator; finally, spraying the organic mixed solution onto the surface of the semi-finished composite lithium-replenishing separator and baking and drying it to form the lithium-replenishing functional coating 200. Specifically, thickeners, binders, and wetting agents are added to deionized water and stirred until completely dissolved. Then, surface-treated inorganic particles 202 are added, stirred evenly, and ground for 1-8 hours. Next, surfactants are added, and the mixture is ground again for 1-12 hours to obtain an aqueous inorganic slurry. The aqueous inorganic slurry is then coated onto a designated surface of the base film layer 100 and dried in an oven at 40-90℃ for 15-120 minutes to obtain a semi-finished composite lithium-replenishing separator. Lithium-modified organic materials and water are added to a mixer and stirred for 30-120 minutes to fully dissolve the powder mixture to obtain an organic mixed solution. The organic mixed solution is then sprayed onto the surface of the semi-finished composite lithium-replenishing separator corresponding to the designated surface of the base film layer 100 and dried in an oven at 30-80℃ for 10-30 minutes to obtain the lithium-replenishing functional coating 200.

[0100] In some embodiments, the lithium-replenishing functional coating 200 provided in this application is a mixed coating 220 of the lithium-ionized organic particles 201 and the inorganic particles 202. The preparation method of the lithium-replenishing functional coating 220 includes: adding an additive to deionized water to dissolve it as a solvent, wherein the additive includes at least a thickener, a binder, and a wetting agent; adding the inorganic material and the lithium-ionized organic material to the solvent to obtain a mixed slurry; coating the mixed slurry on the surface of the base film layer 100, and baking and drying it to form the lithium-replenishing functional coating 200. Specifically, thickeners, binders, and wetting agents are added to deionized water and stirred until completely dissolved. Then, surface-treated inorganic particles 202 and lithium-ionized organic particles 201 are added, stirred evenly, and ground for 1-8 hours. Then, surfactants are added, and the mixture is ground again for 1-12 hours to obtain a mixed slurry. The mixed slurry is then coated onto a designated surface of the base film layer 100 and dried in an oven at 30-80°C for 10-30 minutes to obtain the lithium replenishing functional coating 200.

[0101] As can be seen from the above, the stacking of the lithium-ion organic particle coating 210, the inorganic particle coating 221, and the lithium-ion organic particle coating 222, as well as the related preparation method of the mixed coating 220 provided in this application embodiment, overcomes the environmental temperature and humidity control problems caused by the existing lithium powder coating method and solves the problem of excessive lithium replenishment caused by the existing slurry coating method compared with the existing lithium replenishment method. Moreover, the composite lithium replenishment separator does not deteriorate the thermal and mechanical properties of the separator itself. At the same time, it can be prepared on the base film layer 100 of different thicknesses and materials as needed. The thickness of the base film layer 100 can also be adjusted as needed, thereby realizing an ultra-thin lithium replenishment separator, which can meet the lithium replenishment needs of electrodes of different materials and realize product diversification. In addition, the lithium-ion battery composed of the composite lithium replenishment separator also effectively improves the first charge and discharge efficiency and cycle life, and improves the electrical performance of the lithium-ion battery; and the preparation method of the composite lithium replenishment separator is simple and more suitable for large-scale production.

[0102] Based on the same inventive concept, this application also provides a lithium-ion battery. See details. Figure 11The diagram shows a schematic representation of a lithium-ion battery according to an embodiment of this application. The lithium-ion battery provided in this embodiment includes a composite lithium-replenishing separator 10 as described in any of the above embodiments, wherein the composite lithium-replenishing separator 10 is located between the positive electrode 21 and the negative electrode 22 of the lithium-ion battery. Optionally, the material of the positive electrode 21 provided in this embodiment includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, spinel manganese oxide, lithium-rich manganese-based oxide, and lithium manganese iron phosphate; wherein, when the positive electrode 21 includes lithium nickel cobalt manganese oxide, the nickel content of the lithium nickel cobalt manganese oxide ranges from 50% to 98%, the cobalt content ranges from 5% to 30%, and the manganese content ranges from 20% to 40%. Furthermore, the material of the negative electrode 22 provided in this embodiment includes at least one of graphite, silicon-carbon, silicon-oxygen, and a mixture of graphite and silicon; wherein, when the negative electrode 22 includes a mixture of graphite and silicon, the silicon content ranges from 1% to 90%.

[0103] In summary, this application provides a composite lithium-replenishing separator, its preparation method, and a lithium-ion battery. The composite lithium-replenishing separator includes a base film layer and a lithium-replenishing functional coating on at least one side surface of the base film layer, wherein the lithium-replenishing functional coating includes lithium-modified organic particles. The technical solution provided by this application achieves lithium replenishment to the electrodes of a lithium-ion battery through the lithium-modified organic particles in the composite lithium-replenishing separator. This not only improves the performance of the lithium-ion battery but also increases its initial charge-discharge efficiency and cycle life, ensuring high capacity. Since lithium replenishment to the electrodes can be achieved through the lithium-replenishing functional coating, the technical solution provided by this application eliminates the need for high-cost lithium-replenishing agents, effectively reducing the cost of lithium-ion battery electrode lithium replenishment. Furthermore, the composite lithium replenishment membrane only needs to prepare a lithium replenishment functional coating on the surface of the base film layer to achieve the lithium replenishment function. It is not only simple in structure, but also does not deteriorate the thermal and mechanical properties of the base film layer itself. Therefore, the lithium replenishment functional coating can be prepared on the base film layer with different thicknesses and materials according to the requirements. By adjusting the thickness of the base film layer, an ultra-thin composite lithium replenishment membrane can be achieved, thereby meeting the lithium replenishment requirements of electrodes with different materials, realizing product diversification, and making it more suitable for large-scale production needs.

[0104] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and other terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0105] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0106] In the embodiments of this application, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0107] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0108] In the embodiments of this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0109] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A composite lithium-supplementing separator, characterized in that, The composite lithium-supplementing separator comprises: Base film layer; And a lithium replenishing functional coating located on at least one side surface of the base film layer, wherein the lithium replenishing functional coating comprises lithium-ionized organic particles.

2. The composite lithium-supplementing separator according to claim 1, characterized in that, At least one of the lithium replenishing functional coatings includes a lithium-ion organic particle coating, wherein the lithium-ion organic particle coating includes the lithium-ion organic particles; Alternatively, at least one of the lithium replenishing coatings may further include inorganic particles; Alternatively, the composite lithium replenishing membrane includes two lithium replenishing functional coatings located on opposite sides of the base film layer, one of the lithium replenishing functional coatings including the lithium-ion organic particle coating, and the other lithium replenishing functional coating including inorganic particles.

3. The composite lithium-supplementing separator according to claim 2, characterized in that, The D50 particle size of the lithium-ionized organic particles satisfies: 50nm < D50 < 1000nm; The thickness h1 of the lithium-ion organic particle coating satisfies: h1≤0.8×h2, where h2 is the thickness of the base film layer; Furthermore, the coverage of the lithium-ion organic particle coating is 3% to 40%.

4. The composite lithium-supplementing separator according to claim 2, characterized in that, The lithium replenishing coating including the inorganic particles comprises: An inorganic particle coating located on the surface of the base film layer, wherein the inorganic particle coating includes the inorganic particles; And, a lithium-ionized organic particle coating located on the side of the inorganic particle coating opposite to the base film layer, wherein the lithium-ionized organic particle coating includes the lithium-ionized organic particles.

5. The composite lithium-supplementing separator according to claim 4, characterized in that, The D50 particle size of the lithium-ion organic particles satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles; The thickness h3 of the lithium replenishment coating satisfies: h3≤h2, where h2 is the thickness of the base film layer; Furthermore, the thickness of the base film layer ranges from 3 to 30 μm.

6. The composite lithium-supplementing separator according to claim 2, characterized in that, The lithium-replenishing coating, which includes the inorganic particles, is a mixed coating of the lithium-ionized organic particles and the inorganic particles.

7. The composite lithium-supplementing separator according to claim 6, characterized in that, The D50 particle size of the lithium-ion organic particles satisfies: 50nm < D50 < 0.4×d, where d is the particle size of the inorganic particles; The thickness h3 of the lithium replenishment coating satisfies: h3≤h2, where h2 is the thickness of the base film layer; Furthermore, the mass percentage of the lithium-ionized organic particles in the lithium replenishment functional coating ranges from 5% to 20%.

8. The composite lithium-supplementing separator according to any one of claims 1-7, characterized in that, The base film layer includes: a polyethylene base film layer, or a polypropylene base film layer, or a non-woven fabric base film layer, or an aramid base film layer.

9. The composite lithium-supplementing separator according to any one of claims 1-7, characterized in that, The lithium-ion organic material of the lithium-ion organic particles includes at least one of lithium-ion carboxymethyl cellulose, lithium-ion polyacrylic acid, lithium-ion styrene-butadiene rubber, and lithium-ion polyvinylidene fluoride.

10. The composite lithium-supplementing separator according to any one of claims 2-7, characterized in that, The inorganic materials of the inorganic particles include at least one of the following: aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride, and inorganic ceramic solid electrolytes.

11. The composite lithium-supplementing separator according to claim 10, characterized in that, The inorganic ceramic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus sulfide, lithium phosphorus sulfide chloride, and lithium germanium aluminum phosphate.

12. A method for preparing a composite lithium-supplementing separator, characterized in that, The method for preparing the composite lithium-supplementing separator according to any one of claims 1-11 includes: Provide a base film layer; A lithium replenishing functional coating is formed on the surface of at least one side of the base film layer, wherein the lithium replenishing functional coating comprises lithium-ionized organic particles.

13. The method for preparing the composite lithium-supplementing separator according to claim 12, characterized in that, The lithium-supplementing functional coating comprises a lithium-ionized organic particle coating, wherein the preparation method of the lithium-supplementing functional coating includes: A lithium-ionized organic material is mixed with water to obtain an organic mixed solution; The organic mixed solution is sprayed onto the surface of the base film layer and then baked and dried to form the lithium replenishing functional coating.

14. The method for preparing the composite lithium-supplementing separator according to claim 12, characterized in that, The lithium replenishing functional coating includes an inorganic particle coating on the surface of the base film layer, and a lithium-modified organic particle coating on the side of the inorganic particle coating facing away from the base film layer, wherein the preparation method of the lithium replenishing functional coating includes: A method for preparing an aqueous inorganic slurry and an organic mixed solution is described, wherein the method for preparing the aqueous inorganic slurry includes: dissolving an additive in deionized water as a solvent, wherein the additive includes at least a thickener, a binder, and a wetting agent; adding an inorganic material to the solvent to obtain the aqueous inorganic slurry; and the method for preparing the organic mixed solution includes: mixing a lithium-ionized organic material with water to obtain the organic mixed solution. The aqueous inorganic slurry is coated on the surface of the base film layer and preliminarily baked and dried to form a semi-finished composite lithium-supplementing separator; The organic mixed solution is sprayed onto the surface of the semi-finished composite lithium-replenishing separator and then baked and dried to form the lithium-replenishing functional coating.

15. The method for preparing the composite lithium-supplementing separator according to claim 12, characterized in that, The lithium-supplementing functional coating is a mixed coating of lithium-ion organic particles and inorganic particles, wherein the preparation method of the lithium-supplementing functional coating includes: The additive is dissolved in deionized water to form a solvent, wherein the additive includes at least a thickener, a binder, and a wetting agent; Inorganic materials and lithium-ionized organic materials are added to the dissolving solvent to obtain a mixed slurry; The mixed slurry is coated onto the surface of the base film layer and then baked and dried to form the lithium replenishing functional coating.

16. A lithium-ion battery, characterized in that, The lithium-ion battery includes: The composite lithium-replenishing separator according to any one of claims 1-11, wherein the composite lithium-replenishing separator is located between the positive electrode and the negative electrode of the lithium-ion battery.

17. The lithium-ion battery according to claim 16, characterized in that, The positive electrode material includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, spinel manganese oxide, lithium-rich manganese-based oxide, and lithium manganese iron phosphate. Furthermore, the material of the negative electrode includes at least one of graphite, silicon carbide, silicon oxide, and a mixture of graphite and silicon.

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