Lithium-replenished composite separator used in lithium batteries, lithium battery, and method for manufacturing the same.

Abstract

This application provides a lithium-replenishment composite separator for use in lithium batteries, a lithium battery, and a method for manufacturing the same. The lithium battery includes a negative electrode layer and a positive electrode layer, and the lithium-replenishment composite separator is installed between the negative electrode layer and the positive electrode layer, and the lithium-replenishment composite separator includes a separator layer configured to isolate the negative electrode layer and the positive electrode layer, a metallic lithium layer installed on the side of the separator layer closer to the negative electrode layer and configured to replenish lithium in the negative electrode layer, a first protective layer installed on the side of the metallic lithium layer closer to the negative electrode layer, and an electronically conductive layer installed on the side of the metallic lithium layer closer to the negative electrode layer and configured to provide an electronically conductive path between the metallic lithium layer and the negative electrode layer, wherein the orthographic projections of the electronically conductive layer and the first protective layer in the metallic lithium layer do not overlap or overlap locally.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202310323013.1, filed on March 29, 2023, and incorporates the entire text of the aforementioned Chinese Patent Application.

[0002] This application relates to the technical field of lithium batteries, and more specifically to lithium-replenished composite separators used in lithium batteries, lithium batteries, and methods for manufacturing the same. [Background technology]

[0003] Lithium-ion batteries are widely used in people's daily lives as highly efficient energy storage devices. However, with the rapid development of science and technology such as electronic products and electric vehicles, the demand for higher energy density and cycle life in lithium-ion batteries is constantly increasing, and the use of anode materials with high theoretical specific capacity, such as Si-based, Si-O-based, and alloy materials, is becoming increasingly widespread. However, such anode materials undergo relatively large volume changes during the charge and discharge process, making the electrode interface very unstable and causing problems such as low initial Coulomb efficiency and poor cycle performance of the battery.

[0004] To solve the above problems, people have employed many methods, such as chemical reduction, artificial SEI membrane methods, and anode pre-lithiation methods. Of these, anode pre-lithiation is one of the most direct solutions.

[0005] Methods for pre-lithiating negative electrodes are currently divided into four main types: 1. electrochemical pre-lithiating, 2. chemical pre-lithiating, 3. metallic lithium patch method (contact method), and 4. stable metallic lithium powder method. However, each of these four methods has various problems. Electrochemical pre-lithiating is complex to operate and consumes a lot of energy, resulting in very high pre-lithiating costs. Chemical pre-lithiating is highly dangerous because the lithium source used is generally a flammable, explosive, and unstable substance. Stable metallic lithium powder methods are similarly dangerous, and the raw materials are expensive, leading to high pre-lithium costs. Metallic lithium patch method (contact method) is relatively easy to operate, but the utilization rate of metallic lithium is very low, resulting in high pre-lithium costs. Furthermore, because it uses metallic lithium, it is also very dangerous. In addition, the metallic lithium patch method has very high humidity requirements for the pre-lithium environment of the electrode plate and for the storage and use environment of the electrode plate after pre-lithiumization, resulting in high pre-lithium costs. Furthermore, all four of the above pre-lithium methods involve adding new processes, altering the conventional lithium battery manufacturing process, and ultimately reducing the production efficiency of lithium batteries.

[0006] Therefore, there is an urgent need for a highly efficient and simple pre-lithium method. This method must be able to stably pre-lithize the lithium battery anode without reducing the production efficiency of lithium batteries, and the requirements for the production and storage environment must not be too high. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The purpose of this application is to provide a lithium-replenished composite separator for lithium batteries, a lithium battery, and a method for manufacturing the same, which can solve the problem of the low initial Coulomb efficiency of conventional lithium batteries. [Means for solving the problem]

[0008] Embodiments of this application provide a lithium-replenishment composite separator for use in a lithium battery, wherein the lithium battery comprises a negative electrode layer and a positive electrode layer, and the lithium-replenishment composite separator is installed between the negative electrode layer and the positive electrode layer, and the lithium-replenishment composite separator is A separator layer configured to separate the negative electrode layer and the positive electrode layer, A metallic lithium layer is installed on the side of the separator layer closest to the negative electrode layer and configured to replenish lithium in the negative electrode layer, A first protective layer is installed on the side of the metallic lithium layer closest to the negative electrode layer, The metallic lithium layer includes an electronically conductive layer installed on the side of the metallic lithium layer closest to the negative electrode layer, configured to provide an electronically conductive path between the metallic lithium layer and the negative electrode layer, Here, the orthographic projections of the electronically conductive layer and the first protective layer in the metallic lithium layer either do not overlap or overlap locally.

[0009] In some embodiments, the lithium-replenished composite separator is The system further includes a second protective layer installed on the side of the metallic lithium layer away from the negative electrode layer.

[0010] In some embodiments, the lithium-replenished composite separator is The system further includes a second protective layer installed on the side of the separator layer away from the metallic lithium layer.

[0011] In some embodiments, the orthographic shape of the metallic lithium layer in the electronically conductive layer is island-like, where the island-like shape includes a plurality of discontinuous island-like shapes and / or a mesh-like shape formed by the interconnection of a plurality of island-like shapes.

[0012] In some embodiments, the thickness of the electronically conductive layer is greater than the thickness of the first protective layer.

[0013] In some embodiments, the thickness of the electronically conductive layer is 10 nm to 1000 nm.

[0014] In some embodiments, the coverage rate of the metal lithium layer in the electron conductive layer is 10% to 90%.

[0015] In some embodiments, the area of a single said electron conductive layer is 100 nm 2 to 1,000,000 nm 2 is.

[0016] In some embodiments, the thickness of the first protective layer and / or the second protective layer is 10 nm to 1000 nm.

[0017] In some embodiments, the thickness of the metal lithium layer is 0.1 μm to 10 μm, and the metal lithium layer has a dense or porous hydrophobic structure.

[0018] In some embodiments, the material of the electron conductive layer includes at least one of a metal, a metal oxide, a metal nitride, a metal sulfide, or a carbon material.

[0019] In some embodiments, the metal material includes at least one of gold, silver, copper, iron, titanium, aluminum, manganese, tin, cobalt, nickel, chromium, bismuth, vanadium, molybdenum, or niobium, and the carbon material includes at least one of graphite, hard carbon, soft carbon, graphene, or carbon nanotubes.

[0020] In some embodiments, the material of the first protective layer and / or the second protective layer is Al2O3, MgO, ZnO2, TiO2, ZrO2, LaO2, CeO2, Y2O3, Si x O, SiC, SiN x 、SiCN x 、AlN, Mg(OH)2, BaSO4, boehmite or perovskite, or, Li2CO3, Li3N, LiF, Li3PO4, Li4SiO4, Li4Ti5O 12It contains at least one of LiPON, LiSiON, LLZO, LLZTO, LATP, Li3Fe2(PO4)3, Li3V2(PO4)3, Li3In2(PO4)3, Li3Sc2(PO4)3, and Li3Cr2(PO4)3.

[0021] In some embodiments, the separator layer is one of a base film, a base film / ceramic composite separator, a base film / adhesive composite separator, or a base film / ceramic / adhesive composite separator.

[0022] In some embodiments, the base film includes at least one of the following: polyethylene base film, polyethylene nonwoven base film, polypropylene base film, polypropylene nonwoven base film, polypropylene / polyethylene / polypropylene composite base film, polyimide base film, polyimide nonwoven base film, polytetrafluoroethylene base film, polytetrafluoroethylene nonwoven base film, polyvinyl chloride base film, or polyvinyl chloride nonwoven base film, and / or The ceramic comprises at least one of aluminum oxide, zirconium oxide, boehmite, magnesium hydroxide, barium sulfate, silicon oxide, aluminum nitride, magnesium oxide, titanium dioxide, yttrium oxide, or cerium oxide, and / or The adhesive comprises at least one of the following: polytetrafluoroethylene, polyvinylidene fluoride, acrylic acid, polyethylene oxide, sodium carboxymethylcellulose, styrene-butadiene rubber, hydroxypropyl methylcellulose, carboxystyrene-butadiene rubber, or polyvinyl alcohol.

[0023] In some embodiments, the lithium layer includes at least one of metallic lithium, lithium silicon alloy, lithium magnesium alloy, lithium copper alloy, lithium silver alloy, lithium beryllium alloy, lithium zinc alloy, lithium cadmium alloy, lithium aluminum alloy, lithium gold alloy, and lithium boron alloy.

[0024] Embodiments of this application provide a lithium battery comprising a lithium-replenished composite separator as described in any one of the above claims, wherein the negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer covering the negative electrode current collector layer, and the positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer covering the positive electrode current collector layer.

[0025] The embodiments of this application provide a method for manufacturing a lithium-replenished composite separator, and this method for manufacturing a lithium-replenished composite separator is The steps include providing a separator layer, The steps include forming a metallic lithium layer on one side of the separator layer, The steps include forming an electronically conductive layer on the surface of the metallic lithium layer, The steps include forming a first protective layer on the surface of the metallic lithium layer, Here, the orthographic projections of the electronically conductive layer and the first protective layer in the metallic lithium layer either do not overlap or overlap locally.

[0026] In some embodiments, forming a metallic lithium layer on one side of the separator layer is A second protective layer is formed on one side of the separator layer, This includes forming a metallic lithium layer on the surface of the second protective layer.

[0027] In some embodiments, forming a metallic lithium layer on one side of the separator layer is A second protective layer is formed on one side of the separator layer, This includes forming a metallic lithium layer on the side of the separator layer opposite to the second protective layer.

[0028] In some embodiments, the method for forming the first protective layer and / or the second protective layer is as follows: The method includes at least one of the following: knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0029] In some embodiments, the method for forming the electronically conductive layer includes at least one of knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0030] In some embodiments, the method for forming the metallic lithium layer is as follows: The method includes at least one of the following: vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0031] The embodiments of this application provide a method for manufacturing a lithium battery, and this method for manufacturing a lithium battery is A step of manufacturing a lithium battery negative electrode, which includes a negative electrode current collector layer and a negative electrode active material layer covering the negative electrode current collector layer, A step of manufacturing a lithium battery positive electrode, which includes a positive electrode current collector layer and a positive electrode active material layer covering the positive electrode current collector layer, A step of manufacturing a lithium-replenished composite separator, wherein the method for manufacturing the lithium-replenished composite separator is a step of employing the method described in any one of the above items, The process includes the steps of assembling the lithium-replenished composite separator between the lithium battery negative electrode and the lithium battery positive electrode, and bonding the electronically conductive layer to the negative electrode active material layer. [Effects of the Invention]

[0032] Compared to the prior art, the embodiments of this application have the following technical advantages: The lithium-replenished composite separator described in this application can be directly applied to negative electrode lithium replenishment. The lithium-replenished composite separator provides electronic and ionic conductive paths between the lithium layer and the negative electrode active material. After the battery is assembled, a solid electrolyte thin film (SEI) can be formed in situ, reducing the loss of active lithium and improving the Coulomb efficiency and cycle life of the lithium battery. Furthermore, since the lithium-replenished composite separator described in this application has protective layers on both sides of the lithium layer, it blocks contact between the lithium layer and the external environment, thereby preventing the lithium layer from reacting with air and / or water in the environment, and relatively lowers the storage environment requirements for this lithium-replenished composite separator. [Brief explanation of the drawing]

[0033] The drawings herein are incorporated into the specification and constitute part of this specification, illustrating embodiments conforming to this application and are used together with the specification to interpret the principles of this application. Clearly, the drawings described below are only a few embodiments of this application, and those skilled in the art can obtain other drawings based on these without any creative work. [Figure 1] This is a schematic diagram of the structure of a lithium-filled composite separator according to some embodiments of this application. [Figure 2] This is a schematic diagram of the pattern structure of the electronically conductive layer of a lithium-filled composite separator in some embodiments of this application. [Figure 3] This is a schematic diagram of the structure of a lithium-filled composite separator of several other embodiments of this application. [Figure 4] This is a schematic diagram of the structure of a lithium-filled composite separator of several other embodiments of this application. [Figure 5] This is a schematic diagram of the structure of a lithium-filled composite separator of several other embodiments of this application. [Figure 6] This is a schematic diagram of the structure of a lithium battery in several embodiments of this application. [Figure 7]This is a schematic diagram of the structure of a lithium battery in several other embodiments of this application. [Figure 8] This is a flowchart of the manufacturing method for several embodiments of the present application of a lithium-filled composite separator. [Figure 9] This is a flowchart of the manufacturing method of a lithium battery according to some embodiments of this application. [Figure 10] This is a schematic diagram of the open-circuit voltage change curves for several embodiments and comparative examples of this application. [Figure 11] This is a schematic diagram of the initial charge-discharge curves for several embodiments and comparative examples of this application. [Figure 12] This is a schematic diagram of the experimental results of the initial state of Examples 1 and 2 of this application. [Figure 13] This is a schematic diagram of the experimental results after leaving Examples 1 and 2 of this application for 15 days. [Figure 14] This is a schematic diagram of the experimental results after leaving Examples 1 and 2 of this application for 30 days. [Figure 15] This is a schematic diagram of the open-circuit voltage change curves after 30 days of storage for several embodiments and comparative examples of this application. [Figure 16] This is a schematic diagram showing the room-temperature cycling results of several embodiments and comparative examples of this application. [Modes for carrying out the invention]

[0034] To clarify the purpose, technical proposal, and merits of this application, the application is described in more detail below, accompanied by drawings. Clearly, the described embodiments are only a selection of embodiments of this application, not all embodiments. All other embodiments derived from the embodiments in this application, without requiring any creative effort by a person skilled in the art, are all within the scope of protection of this application.

[0035] The terms used in the embodiments of this application are for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms “one,” “the said,” and “the said” used in the embodiments of this application and in the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, “plural” generally includes at least two.

[0036] It should be understood that the terms "and / or" as used herein merely describe the relationship between related objects, indicating that three relationships are possible. For example, A and / or B may represent three cases: A existing alone, A and B existing simultaneously, or B existing alone. Also, the letter " / " in this specification generally indicates that the preceding and following related objects are in an "or" relationship.

[0037] It should be understood that while the embodiments of this application may be described using terms such as first, second, third, etc., these terms should not be used as a limiting factor. These terms are used solely for distinction. For example, without departing from the scope of the embodiments of this application, the first may be called the second, and similarly, the second may be called the first.

[0038] It should be further explained that the terms “include,” “incorporate,” or any other variation thereof are intended to cover non-exclusive inclusion, thereby including not only those elements but also other elements not explicitly listed, or elements specific to such goods or devices. Unless otherwise specified, an element limited by the phrase “includes one” does not preclude the presence of other identical elements in the goods or devices that include the aforementioned element.

[0039] In lithium battery manufacturing technologies, the poor electron conductivity and lithium-ion conductivity of the positive and negative electrode separators used in lithium-ion batteries result in low initial Coulomb efficiency (Coulomb efficiency refers to the ratio of battery discharge capacity to charge capacity in the same cycle process; the input energy is often not fully used to convert the active material into a charged state, and some is consumed, for example, irreversible side reactions occur, so Coulomb efficiency is often less than 100%) and poor cycle performance. Pre-lithiumization or lithium replenishment of the negative electrode is the most direct way to improve negative electrode performance, and therefore, there is an urgent need for a highly efficient and simple lithium replenishment method. This method can stably replenish lithium to the negative electrode of lithium batteries, does not reduce the production efficiency of lithium batteries, and does not place excessively high demands on the production and storage environment.

[0040] Embodiments of this application provide a lithium-replenishment composite separator for use in a lithium battery, the lithium battery comprising a negative electrode layer and a positive electrode layer, the lithium-replenishment composite separator being placed between the negative electrode layer and the positive electrode layer to isolate the negative electrode layer and simultaneously replenish lithium in the negative electrode layer, wherein the lithium-replenishment composite separator comprises a separator layer configured to isolate the negative electrode layer and the positive electrode layer, a metallic lithium layer placed on the side of the separator layer closer to the negative electrode layer and configured to replenish lithium in the negative electrode layer, a first protective layer placed on the side of the metallic lithium layer closer to the negative electrode layer, and an electronically conductive layer placed on the side of the metallic lithium layer closer to the negative electrode layer and configured to provide an electronically conductive path between the metallic lithium layer and the negative electrode layer, wherein the orthographic projections of the electronically conductive layer and the first protective layer on the metallic lithium layer do not overlap or locally overlap.

[0041] The lithium-replenishment composite separator of this application can be directly applied to negative electrode lithium replenishment, thereby improving the initial Coulomb efficiency and cycle life of lithium batteries. The lithium-replenishment composite separator of this application allows control over the degree of lithium replenishment (pre-lithification) by adjusting and controlling the thickness of the metallic lithium layer, and improves the utilization rate of lithium during the pre-lithification process. The composite separator of this application provides an electronically conductive path between the metallic lithium layer and the negative electrode active material, thereby reducing the generation of dead lithium and further improving the utilization rate of lithium. The lithium-replenishment composite separator of this application does not alter the normal production process flow of lithium batteries and does not reduce the production efficiency of lithium batteries. The lithium-replenishment composite separator of this application has protective layers on both sides of the metallic lithium layer, blocking contact between the metallic lithium layer and the external environment, thereby preventing the metallic lithium layer from reacting with air and / or water in the environment, so this lithium-replenishment composite separator has relatively low requirements for the storage environment. Furthermore, the lithium-replenished composite separator of this application provides electronic and ionic conductive paths between the metallic lithium layer and the negative electrode active material, allowing a solid electrolyte thin film (SEI) to be formed in situ after the battery is assembled, further reducing the loss of active lithium and improving the Coulomb efficiency and cycle life of the lithium battery.

[0042] The following describes in detail some of the selective embodiments of this application, accompanied by the drawings.

[0043] As shown in Figures 1 and 6, embodiments of this application provide a lithium replenishment composite separator 1 for use in a lithium battery, the lithium battery comprising a negative electrode layer 3 and a positive electrode layer 4, the lithium replenishment composite separator 1 being installed between the negative electrode layer 3 and the positive electrode layer 4, the lithium replenishment composite separator 1 being able to directly replenish lithium to the lithium battery negative electrode layer 3, thereby improving the initial Coulomb efficiency and cycle life of the lithium battery, as shown in Figure 6, the negative electrode layer 3 comprising a negative electrode current collector layer 301 and a negative electrode active material layer 302, and the positive electrode layer 4 comprising a positive electrode current collector layer 401 and a positive electrode active material layer 402. Here, as shown in Figure 1, the lithium-replenished composite separator 1 includes a separator layer 101 configured to separate the negative electrode layer 3 and the positive electrode layer 4, a metallic lithium layer 103 installed on the side of the separator layer 101 closer to the negative electrode layer 3 and configured to replenish lithium in the negative electrode layer 3, a first protective layer 105 installed on the side of the metallic lithium layer 103 closer to the negative electrode layer 3, and an electronically conductive layer 104 installed on the side of the metallic lithium layer 103 closer to the negative electrode layer 3 and configured to provide an electronically conductive path between the metallic lithium layer 103 and the negative electrode layer 3, wherein the orthographic projections of the electronically conductive layer 104 and the first protective layer 105 on the metallic lithium layer 103 do not overlap or overlap locally.

[0044] In some embodiments, as shown in Figures 1 and 6, the separator layer 101 is used to separate the negative electrode layer 3 and the positive electrode layer 4. Its thickness is generally 5 μm to 300 μm, and may be selected from, for example, 50 μm, 100 μm, 200 μm, 250 μm, etc., and will not be explained further here. Different thicknesses may be selected depending on the type of material of the separator layer 101. If the thickness of the separator layer 101 is greater than 300 μm, the manufacturing efficiency of the lithium battery will decrease, and if the thickness of the separator layer 101 is less than 5 μm, the positive and negative electrodes of the lithium battery are likely to be damaged, causing a short circuit.

[0045] In some embodiments, the type of separator layer may include a base film, a base film / ceramic composite separator, a base film / adhesive composite separator, and a base film / ceramic / adhesive composite separator.

[0046] Here, the base film may be at least one or more combinations of polyethylene base film, polyethylene nonwoven fabric base film, polypropylene base film, polypropylene nonwoven fabric base film, polypropylene / polyethylene / polypropylene composite base film, polyimide base film, polyimide nonwoven fabric base film, polytetrafluoroethylene base film, polytetrafluoroethylene nonwoven fabric base film, polyvinyl chloride base film, and polyvinyl chloride nonwoven fabric base film, and is not limited to the type or number of combinations.

[0047] The ceramic may be a combination of at least one or more of the following: aluminum oxide, zirconium oxide, boehmite, magnesium hydroxide, barium sulfate, silicon oxide, aluminum nitride, magnesium oxide, titanium dioxide, yttrium oxide, and cerium oxide, and is not limited to the type or number of combinations.

[0048] The adhesive may be a combination of at least one or more of the following: polytetrafluoroethylene, polyvinylidene fluoride, acrylic acid, polyethylene oxide, sodium carboxymethylcellulose, styrene-butadiene rubber, hydroxypropyl methylcellulose, carboxystyrene-butadiene latex, and polyvinyl alcohol, and is not limited to the type or number of combinations.

[0049] In some embodiments, as shown in Figures 1 and 6, the metallic lithium layer 103 is placed on the side of the separator layer 101 closer to the negative electrode layer 3 as a core layer that plays a role in lithium replenishment. The thickness of the metallic lithium layer is 0.1 μm to 10 μm, and may be selected to be, for example, 0.1 μm to 0.3 μm, 0.3 μm to 1 μm, 1 μm to 3 μm, 3 μm to 6 μm, 6 μm to 10 μm, etc. No further explanation is given here. Different thicknesses may be selected depending on the material type of the metallic lithium layer. By adjusting and controlling the thickness of the metallic lithium layer, the degree of lithium replenishment (pre-lithification) can be controlled, and the utilization rate of lithium in the pre-lithification process can be improved. Here, the surface of the metallic lithium layer may be made of a dense material or a porous, sparse structure material, and is not limited to these.

[0050] In some embodiments, the material of the metallic lithium layer may be pure metallic lithium, a lithium alloy material, or a composite layer of pure metallic lithium and a lithium alloy material, where the lithium alloy material includes, for example, at least one or more combinations of metallic lithium, lithium silicon alloy, lithium magnesium alloy, lithium copper alloy, lithium silver alloy, lithium beryllium alloy, lithium zinc alloy, lithium cadmium alloy, lithium aluminum alloy, lithium gold alloy, and lithium boron alloy, and is not specifically limited to any free combination of the above-mentioned materials.

[0051] In some embodiments, as shown in FIGS. 1 and 6, the first protective layer 105 is disposed on the side of the metallic lithium layer 103 close to the negative electrode layer 3. The first protective layer 105 is a single layer disposed between the metallic lithium layer 103 and the negative electrode layer 3. The first protective layer 105 locally covers the metallic lithium layer 103, for example, locally covers 10% to 90% of the metallic lithium layer 103, thereby avoiding the local or overall exposure of the metallic lithium layer 103 to air, humid air and / or water. Since the metallic lithium layer is prone to react with air or water, the first protective layer 105 isolates the metallic lithium layer from the external environment, blocks the contact between the metallic lithium layer and air and / or moisture, reduces the occurrence of side reactions of the metallic lithium layer, plays a protective role for the metallic lithium layer, and thereby reduces the demand for its storage environment.

[0052] In some embodiments, the thickness of the first protective layer is 10 nm to 1000 nm. For example, 10 nm to 100 nm, 100 nm to 300 nm, 300 nm to 600 nm, 600 nm to 900 nm, 1000 nm, etc. may be selected. Without further explanation here, different thicknesses may be selected according to the type of material of the first protective layer.

[0053] In some embodiments, the first protective layer selects a high ion-conductive material, which can provide protection for the metallic lithium layer, improve the ion conductivity of the entire lithium replenishment composite separator at the same time, and improve the lithium replenishment efficiency and effect during its use process. Specifically, the material of the first protective layer is Al2O3, MgO, ZnO2, TiO2, ZrO2, LaO2, CeO2, Y2O3, Si x O, SiC, SiN x , SiCN x , AlN, Mg(OH)2, BaSO4, boehmite or perovskite, or Li2CO3, Li3N, LiF, Li3PO4, Li4SiO4, Li4Ti5O 12At least one or more combinations of lithium nitrogen phosphate (LiPON), LiSiON, lithium lanthanum zirconium oxide (LLZO), tantalum-doped lithium lanthanum zirconium oxide (LLZTO), lithium aluminum titanium phosphate (LATP), Li3Fe2(PO4)3, Li3V2(PO4)3, Li3In2(PO4)3, Li3Sc2(PO4)3, and Li3Cr2(PO4)3 may be selected, and there are no limitations on the type or number of combinations.

[0054] In some embodiments, as shown in Figures 1 and 6, the electronically conductive layer 104 is located on the side of the metallic lithium layer 103 closer to the negative electrode layer 3 and is configured to provide an electronically conductive path between the metallic lithium layer 103 and the negative electrode layer 3, both of which are located on the surface of the metallic lithium layer 103, and the orthographic projections of the electronically conductive layer 104 and the first protective layer 105 on the metallic lithium layer 103 do not overlap or overlap locally. For example, the electronically conductive layer in Figure 1 is prism-shaped 1043, which does not overlap with the orthogonal projection of the metallic lithium layer 103 of the first protective layer 105. Alternatively, the electronically conductive layer in Figure 1 may be inverted cone or inverted trapezoid shape 1042, or the electronically conductive layer may be regular cone or trapezoid shape 1041, where the cone or trapezoid shape may be regular, for example, a cone or frustocone shape, or an irregular cone or trapezoid shape, which locally overlaps with the orthogonal projection of the metallic lithium layer 103 of the first protective layer 105, i.e., there is overlap at the edges, the overlap area is relatively small, and the electronically conductive layer does not affect the provision of electronically conductive paths. By positioning the electronically conductive layer 104 and the first protective layer 105 so as to locally overlap the orthographic projection of the metallic lithium layer 103, the sealing performance between the electronically conductive layer 104 and the first protective layer 105 can be improved, creating a seamless state between them. This ensures that the electronically conductive layer 104 and the first protective layer 105 can completely cover the metallic lithium layer 103, further isolating the metallic lithium layer from the external environment, blocking contact between the metallic lithium layer and air and / or moisture, reducing the possibility of side reactions occurring in the metallic lithium layer, and providing absolute protection for the metallic lithium layer.

[0055] As an example, the advantages of cone-shaped or trapezoid-shaped electronic conductive layers can be explained. For example, one method for forming the electronic conductive layer 104 and the first protective layer 105 involves setting a mask for the electronic conductive layer, first forming the first protective layer by one or a combination of two or more methods such as knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, and pulsed laser deposition, then removing the mask, and finally forming the electronic conductive layer 104 by one or a combination of two or more sputtering methods such as high-frequency sputtering, magnetron sputtering, or reactive sputtering. Forming each conductive unit in the electronic conductive layer into a cone-shaped or trapezoid-shaped form significantly reduces the gap between each conductive unit and the protective layer, thereby improving protection against the metallic lithium layer.

[0056] As a specific example, the orthographic projections of the electronically conductive layer 104 and the metallic lithium layer 103 of the first protective layer 105 do not overlap and both have a regular prismatic shape 1043. By forming an electronically conductive layer 104 with a regular matrix arrangement through a masking process, the uniformity of the electronically conductive layer 104 can be improved.

[0057] As a specific example, the orthographic projections of the electronically conductive layer 104 and the metallic lithium layer 103 of the first protective layer 105 overlap, and both are irregular inverted cone or inverted trapezoid shape 1042 or regular cone or trapezoid shape 1041. The electronically conductive layer 104 is formed in a matrix arrangement by a sputtering process, and the sealing properties of the electronically conductive layer 104 can be enhanced.

[0058] In some embodiments, as shown in Figure 2, the orthographic shape of the electronically conductive layer 104 in the metallic lithium layer 103 is island-like, where the orthographic projection of the electronically conductive layer 104 in the metallic lithium layer 103 is an isolated, discontinuous conductive unit, and the island-like shape includes one or more discontinuous conductive units 1044 and / or at least one mesh-like shape 1045 formed by multiple conductive units in communication. The electronically conductive layer 104 is arranged on the metallic lithium layer 103 in a regular or irregular pattern. For example, the orthographic projection of the electronically conductive layer 104 on the metallic lithium layer 103 may be a discontinuous island-like pattern 1044 or a mesh-like pattern 1045. The discontinuous island-like pattern 1044 may be a group of aggregated but non-communicating island-like patterns. The mesh-like pattern 1045 may consist of multiple island-like patterns that are close together to form a continuous island-like pattern, meaning that multiple conductive units communicate with each other. However, the mesh-like pattern 1045 may also consist of multiple island-like units linearly connected by a conductive material. The electrical conductivity of multiple island-like units is maintained on the premise that the position occupied by a single island-like structure is not changed. If one of the island-like conductive units becomes non-conductive, electrons can still be transmitted by the other island-like conductive units without changing the conductive area, thereby not significantly reducing the conductivity of the electronically conductive layer 104. For the electronically conductive layer 104, the process required to form one or more discontinuous conductive units 1044 and / or at least one mesh-like structure 1045 formed by multiple interconnected conductive units is simple, does not require particular control of the position of sputtering points or the amount of sputtering material during the sputtering process, island-like conductive units can be formed, the growth position of the deposited material can be flexibly controlled during the process of forming the first protective layer by the deposition process, and after forming conical conductive units by sputtering, a dense protective layer may be formed around the island-like conductive units by the deposition process, thereby enhancing isolation protection from the metallic lithium layer.In some embodiments, the thickness of the electronically conductive layer 104 is greater than the thickness of the first protective layer 105, prioritizing sufficient conductivity between the metallic lithium layer 103 and the negative electrode layer 3 via the electronically conductive layer 104, providing an electronically conductive path from the metallic lithium layer 103 to the negative electrode layer 3, thereby improving lithium replenishment efficiency. The electronically conductive layer provides a high-speed electronically conductive path between the metallic lithium layer and the negative electrode active material, increasing the reaction sites between the metallic lithium layer and the negative electrode active material, improving the reaction rate of the metallic lithium layer, improving lithium replenishment efficiency, reducing and even avoiding the generation of dead lithium, improving the utilization rate of the metallic lithium layer, and reducing costs. In the absence of the electronically conductive layer, metallic lithium is prone to aggregation, causing the generation of a relatively large amount of dead lithium. After adding the electronically conductive layer, the reaction sites between the lithium layer and the negative electrode active material increase, the current density is dispersed, aggregation is less likely to occur, effectively reducing the generation of dead lithium, improving the utilization rate of the lithium layer, and further saving costs.

[0059] In some embodiments, the thickness of the electronically conductive layer is 10 nm to 1000 nm, and may be selected from, for example, 10 nm to 100 nm, 100 nm to 300 nm, 300 nm to 600 nm, 600 nm to 900 nm, 1000 nm, etc., and will not be explained further here. Different thicknesses may be selected depending on the type of material of the electronically conductive layer.

[0060] In some embodiments, as shown in Figures 1 and 2, the coverage rate of the electronically conductive layer 104 over the metallic lithium layer 103 is 10% to 90%, and together with the first protective layer 105, complete 100% coverage of the metallic lithium layer 103. This prevents the surface of the metallic lithium layer 103 from being completely exposed to air, water, and / or moisture, completely blocking contact between the lithium layer and air and / or moisture, reducing the occurrence of side reactions in the lithium layer, providing protection for the metallic lithium layer, and lowering its storage environment requirements.

[0061] In some embodiments, when the electronically conductive layer is distributed in multiple discontinuous island-like formations, the area of ​​a single conductive unit is 100 nm.2 ~1,000,000 nm 2 It may also be 100nm 2 ~100,000 nm 2 , 100,000 nm 2 ~500,000 nm 2 , 500,000nm 2 ~1,000,000 nm 2 You may choose options such as these, and without further explanation here, you may select different areas depending on the type of material used for the electronically conductive layer in order to ensure sufficient conductivity between the metallic lithium layer and the negative electrode layer.

[0062] In some embodiments, the material of the electronically conductive layer includes at least one or more random combinations of metals, metal oxides, metal nitrides, metal sulfides, or carbon materials. Here, the metal material includes at least one of gold, silver, copper, iron, titanium, aluminum, manganese, tin, cobalt, nickel, chromium, bismuth, vanadium, molybdenum, or niobium; the metal oxide, metal nitride, or metal sulfide includes at least one of metal oxides, metal nitrides, or metal sulfides of gold, silver, copper, iron, titanium, aluminum, manganese, tin, cobalt, nickel, chromium, bismuth, vanadium, molybdenum, or niobium; and the carbon material includes at least one of graphite, hard carbon, soft carbon, graphene, or carbon nanotubes.

[0063] The lithium-replenished composite separator of this application provides electronic and ionic conductive paths between the metallic lithium layer and the negative electrode active material, allowing a solid electrolyte thin film (SEI) to be formed in situ after the battery is assembled, further reducing the loss of active lithium and improving the Coulomb efficiency and cycle life of the lithium battery.

[0064] In some embodiments, as shown in Figure 3, the lithium-replenished composite separator 1 further includes a second protective layer 102 located on the side of the metallic lithium layer 103 away from the negative electrode layer 3, as can be seen in conjunction with Figure 6. In this embodiment, the second protective layer 102 is attached to the side of the lithium metallic layer 103 opposite to the first protective layer 105. By placing the first protective layer 105 and the second protective layer 102 on the upper and lower surfaces of the lithium metallic layer 103, respectively, the risk of exposure on the other side of the lithium metallic layer 103 is further blocked, preventing localized or overall exposure of the lithium metallic layer 103 to air, humid air, and / or water. Here, localized exposure can cause the lithium metallic layer 103 to react with air or water due to penetration (e.g., air permeability or water permeability) of other non-dense film layers. Therefore, by installing the second protective layer 102, the lithium metallic layer can be further completely isolated from the external environment, blocking contact between the lithium metallic layer and air and / or moisture, further reducing the occurrence of side reactions in the lithium metallic layer, and further protecting the lithium metallic layer, thereby lowering the requirements for its storage environment.

[0065] In some embodiments, the thickness of the second protective layer is 10 nm to 1000 nm, and may be selected from, for example, 10 nm to 100 nm, 100 nm to 300 nm, 300 nm to 600 nm, 600 nm to 1000 nm, etc., and will not be explained further here. Different thicknesses may be selected depending on the type of material of the second protective layer.

[0066] In some embodiments, the second protective layer is made of a highly ionic conductive material, which provides protection to the metallic lithium layer while simultaneously improving the overall ionic conductivity of the lithium-replenished composite separator, thereby improving the lithium-replenishment efficiency and effectiveness during use. Specifically, the material of the second protective layer is: Al2O3, MgO, ZnO2, TiO2, ZrO2, LaO2, CeO2, Y2O3, Si x O, SiC, SiN x integrativeSiCN x AlN, Mg(OH)2, BaSO4, boehmite or perovskite, or Li2CO3, Li3N, LiF, Li3PO4, Li4SiO4, Li4Ti5O 12 It contains at least one of LiPON, LiSiON, LLZO, LLZTO, LATP, Li3Fe2(PO4)3, Li3V2(PO4)3, Li3In2(PO4)3, Li3Sc2(PO4)3, and Li3Cr2(PO4)3.

[0067] In some other embodiments, as shown in Figure 4, in addition to the embodiments described above, the lithium-replenished composite separator 1 further includes a second protective layer 102 located on the side of the separator layer 101 away from the metallic lithium layer 103. In this embodiment, the second protective layer 102 is attached to the separator layer 101 on the side opposite to the first protective layer 105. By placing the second protective layer 102 on the underside of the separator layer 101, the first protective layer 105 and the second protective layer 102 are indirectly placed on the upper and lower surfaces of the metallic lithium layer 103, respectively. This further blocks the exposure risk on the other side of the metallic lithium layer 103, preventing localized or overall exposure of the metallic lithium layer 103 to air, humid air, and / or water. By placing the second protective layer 102 on the underside of the separator layer 101, the entirety of the first protective layer 105 and the second protective layer 102 are positioned on the upper and lower surfaces of the lithium-replenished composite separator 1, providing a certain level of protection to each film layer inside the lithium-replenished composite separator 1. At the same time, the manufacturing process of the second protective layer is simplified, improving the overall manufacturing efficiency of the lithium-replenished composite separator 1.

[0068] In some other embodiments, as shown in Figure 5, in addition to the embodiments described above, the lithium-replenished composite separator simultaneously includes a first protective layer 105, a second protective layer 102, and a third protective layer 106. That is, the lithium-replenished composite separator includes, in order, a third protective layer 106, a separator layer 101, a second protective layer 102, a metallic lithium layer 103, an electronically conductive layer 104, and a first protective layer 105. By providing three protective layers, the risk of exposure of the metallic lithium layer is further reduced, and the metallic lithium layer 103 is prevented from being locally or entirely exposed to air, humid air, and / or water.

[0069] The embodiments of this application further provide a lithium battery, as shown in Figure 6, which comprises a positive electrode layer 4, a negative electrode layer 3, an electrolyte, and a lithium-replenished composite separator 1 as described in the embodiments shown in Figure 3 above. Here, the positive electrode layer 4 comprises a positive electrode current collector layer 401 and a positive electrode active material layer 402, and the negative electrode layer 3 comprises a negative electrode current collector layer 301 and a negative electrode active material layer 302. The material of the positive electrode active material layer 402 is a ternary material (abbreviated as nickel (Ni), cobalt (Co), manganese (Mn), NCM), and further comprises lithium cobalt oxide (chemical formula: LiCoO2, abbreviated as LCO), lithium iron phosphate (chemical formula: LiFePO4, abbreviated as LFP), lithium manganese oxide (chemical formula: LiMn2O4, abbreviated as LMO), and lithium nickel manganese oxide (chemical formula: LiNi 0.5 Mn 1.5 The material of the negative electrode active material layer 302 may be a graphite material, and may also be a silicon material, silicon carbon material, silicon dioxide material, soft carbon material, hard carbon material, mesocarbon microbead material, or a combination of other negative electrode materials.

[0070] The embodiments of this application further provide a lithium battery, as shown in Figure 7, which comprises a positive electrode layer 4, a negative electrode layer 3, an electrolyte, and a lithium-replenished composite separator 1 as described in the embodiments shown in Figure 4 above. Here, the positive electrode layer 4 comprises a positive electrode current collector layer 401 and a positive electrode active material layer 402, and the negative electrode layer 3 comprises a negative electrode current collector layer 301 and a negative electrode active material layer 302. The material of the positive electrode active material layer 402 is a ternary (NCM) material, and may further be one or more of lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium manganese oxide (LMO), lithium nickel manganese oxide (LMNO), and a ternary (NCA) material or other positive electrode materials, and the material of the negative electrode active material layer 302 is a graphite material, and may further be one or more of silicon material, silicon carbon material, silicon dioxide material, soft carbon material, hard carbon material, mesocarbon microbead material or other negative electrode material.

[0071] Embodiments of this application provide a method for manufacturing a lithium-filled composite separator, which includes the following steps, as shown in Figure 8: Step S1: Provide a separator layer, Step S2: A metallic lithium layer is formed on one side of the separator layer. Step S3: Form an electronically conductive layer on the surface of the metallic lithium layer. Step S4: A first protective layer is formed on the surface of the metallic lithium layer, wherein the orthographic projections of the electronically conductive layer and the first protective layer on the metallic lithium layer do not overlap or overlap locally.

[0072] In some embodiments, in step S2, forming a metallic lithium layer on one side of the separator layer includes forming a second protective layer on one side of the separator layer and forming a metallic lithium layer on the surface of the second protective layer.

[0073] In some embodiments, in step S2, forming a metallic lithium layer on one side of the separator layer includes forming a second protective layer on one side of the separator layer and forming a metallic lithium layer on the side of the separator layer opposite to the second protective layer.

[0074] In some embodiments, the method for forming the first protective layer and / or the second protective layer is as follows: The method includes at least one of the following: knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0075] In some embodiments, the method for forming the electronically conductive layer includes at least one of knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0076] In some embodiments, the method for forming the metallic lithium layer includes at least one of vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

[0077] Embodiments of this application provide a method for manufacturing a lithium battery, which includes the following steps, as shown in Figure 9: Step S11: A lithium battery negative electrode is manufactured, which includes a negative electrode current collector layer and a negative electrode active material layer covering the negative electrode current collector layer. Step S12: A lithium battery positive electrode is manufactured, wherein the lithium battery positive electrode comprises a positive electrode current collector layer and a positive electrode active material layer covering the positive electrode current collector layer. Step S13: Manufacture a lithium-refilled composite separator, wherein the method for manufacturing the lithium-refilled composite separator is the method described in any one of the above items: Step S14: Assemble the lithium-replenished composite separator between the lithium battery negative electrode and lithium battery positive electrode, and bond the electronically conductive layer to the negative electrode active material layer.

[0078] <Comparative Example 1> This comparative example provides a method for manufacturing a ceramic-coated separator and a lithium battery, and includes the following steps: (1) A lithium-ion battery positive electrode is manufactured, wherein the lithium-ion battery positive electrode comprises a positive electrode current collector and an active material layer coated on the surface of the positive electrode current collector. (2) A lithium-ion battery anode is manufactured, wherein the lithium-ion battery anode includes a negative electrode current collector and an active material layer coated on the surface of the negative electrode current collector. (3) Manufacturing of lithium batteries: The positive electrode, negative electrode, and aluminum oxide ceramic coated separator obtained in step (1) and step (2) are assembled into a battery and tested.

[0079] <Comparative Example 2> This comparative example provides a method for manufacturing a lithium-replenished negative electrode plate and a lithium battery, the manufacturing method comprising the following steps: (1) A lithium-ion battery negative electrode is manufactured, wherein the lithium-ion battery negative electrode includes a negative electrode current collector and an active material layer coated on the surface of the negative electrode current collector. (2) A lithium-replenished negative electrode is manufactured, and a lithium layer is deposited on the surface of the battery negative electrode active material obtained in step (1) using magnetron sputtering technology, wherein the deposited metallic lithium is metallic and has a thickness of 1000 nm. (3) A protective layer is fabricated on the surface of the metallic lithium layer of the lithium-replenished negative electrode obtained in step (2), which is Li2CO3 and has a thickness of 30 nm. (4) A lithium-ion battery positive electrode is manufactured, wherein the lithium-ion battery positive electrode comprises a positive electrode current collector and an active material layer coated on the surface of the positive electrode current collector. (5) The lithium-replenished negative electrode plate, positive electrode plate, and aluminum oxide ceramic coated separator obtained in steps (3) and (4) were assembled into a battery and tested.

[0080] <Comparative Example 3> This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) A lithium-filled composite separator is manufactured by depositing a metallic lithium layer on the surface of an aluminum oxide ceramic coated separator using vacuum deposition technology, with a thickness of 1000 nm. (2) A first protective layer is fabricated on the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (1), the material being Li2CO3 and having a thickness of 30 nm. (3) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (4) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (5) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (2), (3), and (4) into a battery and perform a test.

[0081] <Comparative Example 4> This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) A lithium-filled composite separator is manufactured by depositing a second protective layer on the surface of an aluminum oxide ceramic coated separator using magnetron sputtering technology. The material is LiPON, and the thickness is 100 nm. (2) On the surface of the second protective layer of the lithium-filled composite separator obtained in step (1), a metallic lithium layer is deposited on the surface of the aluminum oxide ceramic coated separator using vacuum deposition technology, the thickness of the deposited metallic lithium layer being 1000 nm. (3) A first protective layer is fabricated on the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (2), the material being Li2CO3 and having a thickness of 30 nm. (4) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (5) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (6) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (3), (4), and (5) into a battery and perform a test. [Examples]

[0082] This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) A lithium-filled composite separator is manufactured by depositing a metallic lithium layer on the surface of an aluminum oxide ceramic coated separator using vacuum deposition technology, with a thickness of 1000 nm. (2) On the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (1), an electronically conductive layer is deposited on the surface of the metallic lithium layer using magnetron sputtering technology. The material is silver, the coverage of the electronically conductive layer on the metallic lithium layer is 30%, and the average area of ​​a single conductive unit of multiple conductive units in the electronically conductive layer is 2500 nm. 2 And, (3) A first protective layer is fabricated on the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (2), the material being Li2CO3 and the thickness being 30 nm. (4) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (5) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (6) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (3), (4), and (5) into a battery and perform a test. [Examples]

[0083] This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) A lithium-filled composite separator is manufactured by depositing a second laminated protective layer on the surface of an aluminum oxide ceramic coated separator using magnetron sputtering technology. The material is LiPON, and the thickness is 100 nm. (2) On the surface of the second protective layer of the lithium-filled composite separator obtained in step (1), a metallic lithium layer is deposited on the surface of the aluminum oxide ceramic coated separator using vacuum deposition technology, the thickness of the deposited metallic lithium layer being 1000 nm. (3) On the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (2), an electronically conductive layer is deposited on the surface of the metallic lithium layer using magnetron sputtering technology. The material is silver, the coverage of the electronically conductive layer on the metallic lithium layer is 30%, and the average area of ​​a single conductive unit of multiple conductive units in the electronically conductive layer is 2500 nm. 2 And, (4) A first protective layer is fabricated on the surface of the metallic lithium layer of the lithium-replenished composite separator obtained in step (3), the material being Li2CO3 and having a thickness of 30 nm. (5) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (6) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (7) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (3), (4), and (5) into a battery and perform a test. [Examples]

[0084] This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) Store the lithium-replenished separator obtained in step (3) of Example 1 in a dry air environment for 30 days. (2) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (3) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (4) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (1), (2), and (3) into a battery and perform a test. [Examples]

[0085] This embodiment provides a method for manufacturing a lithium-replenished composite separator and a lithium battery, and includes the following steps: (1) Store the lithium-replenished separator obtained in step (4) of Example 2 in a dry air environment for 30 days. (2) A lithium-ion battery positive electrode layer is manufactured, wherein the lithium-ion battery positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer that covers the surface of the positive electrode current collector layer. (3) A lithium-ion battery negative electrode layer is manufactured, wherein the lithium-ion battery negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer that covers the surface of the negative electrode current collector layer. (4) Assemble the lithium-replenished composite separator, positive electrode layer, and negative electrode layer obtained in steps (1), (2), and (3) into a battery and perform a test.

[0086] The data obtained from testing the lithium batteries in Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Examples 1, 2, 3, and 4 were compared. A summary of the specific data is shown in Table 1, the curve of change in open-circuit voltage is shown in Figure 10, and the initial charge-discharge curve is shown in Figure 11.

[0087] JPEG2026513300000002.jpg107170

[0088] As can be seen by comparing the battery test data in Table 1 with the open-circuit voltage change curve in Figure 10, the initial open-circuit voltage of Comparative Example 1 stabilized at approximately 0.26V, the initial open-circuit voltage of Comparative Example 2 stabilized at approximately 2.89V, the initial open-circuit voltage of Comparative Example 3 stabilized at approximately 3.11V, the initial open-circuit voltage of Comparative Example 4 stabilized at approximately 3.08V, the initial open-circuit voltage of Example 1 was 3.26V, and the initial open-circuit voltage of Example 2 was 3.24V. As can be seen from the above, the initial open-circuit voltage of Examples 1-2 after using the lithium replenishment separator improved significantly, and the initial open-circuit voltage also improved to some extent compared to Comparative Examples 3 and 4. After adopting the lithium replenishment separator (without an electronically conductive layer) of Comparative Examples 3-4, the initial open-circuit voltage showed a gradual increase within the initial time, lasting approximately 10 hours before stabilizing. However, after adopting the lithium replenishment separator (with an electronically conductive layer) described in Example 1-2, a stable initial open-circuit voltage was reached within 3 hours. Therefore, the lithium replenishment composite separator manufactured in Example 1-2 of this application began pre-lithium behavior even before the charge-discharge test after being assembled into a lithium battery, and the pre-lithium rate was significantly improved when an electronically conductive layer was present.

[0089] As can be seen by comparing the battery test data in Table 1 with the initial charge-discharge curves in Figure 11, the initial Coulomb efficiency of Comparative Example 1 was 89.2%, the initial Coulomb efficiency of Comparative Example 2 was 91.9%, the initial Coulomb efficiency of Comparative Example 3 was 93.7%, the initial Coulomb efficiency of Comparative Example 4 was 93.7%, the initial Coulomb efficiency of Example 1 was 94.3%, and the initial Coulomb efficiency of Example 2 was 94.3%. As can be seen from the above, the lithium-replenished composite separator manufactured in Examples 1-2 of this application can effectively improve the initial Coulomb efficiency of lithium batteries, and when an electronically conductive layer is present, the initial Coulomb efficiency is highest and the utilization rate of the metallic lithium layer is clearly improved.

[0090] As can be seen by comparing the battery test data in Table 1 with the initial charge-discharge curves in Figure 11, the initial Coulomb efficiency of Comparative Example 2 was 91.9% and the utilization rate of the metallic lithium layer was 26.1%, the initial Coulomb efficiency of Comparative Example 3 was 93.7% and the utilization rate of the metallic lithium layer was 44.1%, the initial Coulomb efficiency of Comparative Example 4 was 93.7% and the utilization rate of the metallic lithium layer was 44.1%, the initial Coulomb efficiency of Example 1 was 94.3% and the utilization rate of the metallic lithium layer was 49.3%, and the initial Coulomb efficiency of Example 2 was 94.3% and the utilization rate of the metallic lithium layer was 49.3%. As can be seen from the above, in terms of improving the initial efficiency of the lithium battery and the utilization rate of the metallic lithium layer, the lithium-replenished composite separators manufactured in Examples 1-2 of this application are all superior to the lithium-replenished negative electrode plates manufactured in Comparative Examples 2-4, and are particularly superior to the lithium-replenished negative electrode plate manufactured in Comparative Example 2.

[0091] The composite separators obtained in Example 1 and Example 2 were left under the same conditions. The initial state of the separators was shown in Figure 12. After 15 days, the comparison of the separators was shown in Figure 13. After 30 days, the comparison of the separators was shown in Figure 14.

[0092] As can be seen from the comparison between Figure 12 and Figure 13, the changes in the state of the lithium-replenished composite separator obtained in Example 1 and the lithium-replenished composite separator obtained in Example 2 were as follows: After being left for 15 days, many side reactions had already occurred in the metallic lithium layer of the lithium-replenished composite separator of Example 1, resulting in a large number of dark spots on the separator surface. In contrast, as indicated by the arrows in Figure 13, there were no dark spots in the metallic lithium layer of the lithium-replenished composite separator of Example 2, indicating that no side reactions occurred or only a few side reactions occurred.

[0093] As can be seen from the comparison between Figure 12 and Figure 14, the state of the lithium-supplemented composite separator obtained in Example 1 and the lithium-supplemented composite separator obtained in Example 2 changed after being left for 30 days. In Example 1, the metallic lithium layer of the lithium-supplemented composite separator was completely consumed by side reactions, while in Example 2, only a small amount of side reactions occurred in the metallic lithium layer, and only a small amount of dark spots appeared on the separator surface.

[0094] As can be seen by comparing the battery test data in Table 1 with the open-circuit voltage change curve after 30 days of storage in Figure 15, the initial open-circuit voltage of Comparative Example 1 stabilized at approximately 0.26V, and the initial open-circuit voltage of Example 3 was 0.36V, which is not significantly different from the initial open-circuit voltage of Comparative Example 1. However, the initial open-circuit voltage of Example 4 was 3.23V, which is clearly higher than the initial open-circuit voltages of Comparative Example 1 and Example 3. This indicates that pre-lithium behavior still exists before the charge-discharge test after assembling the lithium-replenished composite separator of Example 4, which had been stored for 30 days, into a lithium battery.

[0095] As can be seen by comparing the battery data in Table 1, the initial Coulomb efficiency for Example 3 was 89.5% and the utilization rate of the metallic lithium layer was 0%, while the initial Coulomb efficiency for Example 4 was 92.2% and the utilization rate of the metallic lithium layer was 29.5%. Thus, the prelithium composite separator having a second protective layer can still be prelithiated after being stored for 30 days.

[0096] This demonstrates that in Examples 2 and 4, both of which have a second protective layer, the installation of the second protective layer can play a significant protective role against the metallic lithium layer, thereby improving the storage life and service life of the lithium-replenished composite separator, and reducing the requirements for storage and usage conditions of the lithium-replenished composite separator.

[0097] As can be seen from the comparison of the room-temperature cycle curves in Figure 16, after reaching 80 cycles, the discharge capacity retention rate of Examples 1-2 of this application was higher than that of Comparative Example 1-4. As can be seen from the above, the composite lithium replenishment separator manufactured in Examples 1-2 of this application was able to effectively improve the cycle performance of the lithium battery.

[0098] As can be seen from the comparison of room-temperature cycle curves in Figure 16, the curves for Examples 1-2 of this application are clearly higher than those for Comparative Examples 1-4, indicating that the cycle performance of Examples 1-2 is clearly superior to that of Comparative Example 2. As can be seen from the above, in terms of improving the cycle performance of the battery, the composite lithium-replenished separators manufactured in Examples 1-2 of this application are all superior to the lithium-replenished negative electrode plates of Comparative Examples 1-4.

[0099] As can be seen from the comparison of the room-temperature cycle curves of Comparative Example 3 and Comparative Example 4 in Figure 16, and the comparison of the room-temperature cycle curves of Example 1 and Example 2, the curves of Comparative Example 3 and Comparative Example 4 are almost identical, and the curves of Example 1 and Example 2 are also almost identical, with no significant difference. From the above, it can be seen that the second protective layer does not have any significant side effects on the battery's cycle performance.

[0100] As can be seen from the comparison of the room-temperature cycle curves of Comparative Example 3 and Example 1 in Figure 16, and the comparison of the room-temperature cycle curves of Comparative Example 4 and Example 2, the curve of Example 1 is clearly higher than the curve of Comparative Example 3, and the curve of Example 2 is also clearly higher than the curve of Comparative Example 4. This indicates that the cycle performance of Example 1 is clearly superior to that of Comparative Example 3, and the cycle performance of Example 2 is clearly higher than that of Comparative Example 4. As can be seen from the above, the lithium-replenished composite separator manufactured in this application was able to further improve the cycle performance of the battery when an electronically conductive layer was present.

[0101] The lithium-replenishment composite separator of this application can be directly applied to negative electrode lithium replenishment, thereby improving the initial Coulomb efficiency and cycle life of lithium batteries. The lithium-replenishment composite separator of this application allows control over the degree of lithium replenishment (pre-lithification) by adjusting and controlling the thickness of the lithium layer, and improves the utilization rate of lithium during the pre-lithification process. The composite separator of this application provides an electronically conductive path between the lithium layer and the negative electrode active material, thereby reducing the generation of dead lithium and further improving the utilization rate of lithium. The lithium-replenishment composite separator of this application has the advantage of not altering the normal production process flow of lithium batteries, and thus not reducing the production efficiency of lithium batteries. The lithium-replenishment composite separator of this application has protective layers on both sides of the lithium layer, blocking contact between the lithium layer and the external environment, so that the lithium layer does not react with air and water in the environment, and therefore this lithium-replenishment composite separator has relatively low requirements for the storage environment. Furthermore, the lithium-replenished composite separator of this application provides electronic and ionic conductive paths between the lithium layer and the negative electrode active material, allowing a solid electrolyte thin film (SEI) to be formed in situ after the battery is assembled, further reducing the loss of active lithium and improving the Coulomb efficiency and cycle life of the lithium battery.

[0102] Finally, it should be noted that each example in this specification is described in a step-by-step manner, and each example focuses on explaining the differences from other examples, with any similar or identical parts between examples referring to one another.

[0103] The above embodiments are merely for illustrative purposes and not to limit the technical proposal of this application. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that it is still possible to modify the technical proposals described in the above embodiments or to replace some of their technical features. Such modifications or replacements do not cause the essence of the relevant technical proposal to deviate from the spirit and scope of the technical proposals in each embodiment of this application.

Claims

1. A lithium-refillable composite separator used in a lithium battery comprising a negative electrode layer and a positive electrode layer, wherein the lithium-refillable composite separator is installed between the negative electrode layer and the positive electrode layer, and the lithium-refillable composite separator is A separator layer configured to separate the negative electrode layer and the positive electrode layer, A metallic lithium layer is installed on the side of the separator layer closest to the negative electrode layer and configured to replenish lithium in the negative electrode layer, A first protective layer is installed on the side of the metallic lithium layer closest to the negative electrode layer, The metallic lithium layer includes an electronically conductive layer installed on the side of the metallic lithium layer closest to the negative electrode layer, configured to provide an electronically conductive path between the metallic lithium layer and the negative electrode layer. Here, the orthographic projections of the electronically conductive layer and the first protective layer on the metallic lithium layer locally overlap, creating a seamless state between the electronically conductive layer and the first protective layer, thereby ensuring that the electronically conductive layer and the first protective layer can completely cover the metallic lithium layer. The material of the first protective layer is Al₂O₃, MgO, ZnO₂, TiO₂, ZrO₂, LaO₂, CeO₂, Y₂O₃, SixO, SiC, SiNx, SiCNx, AlN, Mg(OH)₂, BaSO₄, boehmite or perovskite, or It contains at least one of Li2CO3, Li3N, LiF, Li3PO4, Li4SiO4, Li4Ti5O12, LiPON, LiSiON, LLZO, LLZTO, LATP, Li3Fe2(PO4)3, Li3V2(PO4)3, Li3In2(PO4)3, Li3Sc2(PO4)3, and Li3Cr2(PO4)3. A lithium-replenished composite separator characterized in that the method for forming the first protective layer includes at least one of knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

2. The lithium-refilled composite separator is, The lithium-replenished composite separator according to claim 1, further comprising a second protective layer installed on the side of the metallic lithium layer away from the negative electrode layer.

3. The lithium-refilled composite separator is, The lithium-replenished composite separator according to claim 1, further comprising a second protective layer installed on the side of the separator layer away from the metallic lithium layer.

4. The lithium-replenished composite separator according to claim 1, characterized in that the orthographic shape of the metallic lithium layer in the electronically conductive layer is island-like, and the island-like shape includes a plurality of discontinuous island-like shapes and / or at least one mesh-like shape formed by the interconnection of a plurality of island-like shapes.

5. The lithium-replenished composite separator according to claim 1, characterized in that the thickness of the electronically conductive layer is greater than the thickness of the first protective layer.

6. The lithium-replenished composite separator according to claim 1, characterized in that the thickness of the electronically conductive layer is 10 nm to 1000 nm.

7. The lithium-replenished composite separator according to claim 1, characterized in that the coverage rate of the electronically conductive layer over the metallic lithium layer is 10% to 90%.

8. The area of ​​a single electronically conductive layer is 100 nm ２ ~1000000nm ２ The lithium-replenished composite separator according to claim 1, characterized in that it is the same.

9. The lithium-replenished composite separator according to claim 2 or 3, characterized in that the thickness of the first protective layer and / or the second protective layer is 10 nm to 1000 nm.

10. The lithium-replenished composite separator according to claim 1, characterized in that the thickness of the metallic lithium layer is 0.1 μm to 10 μm, and the metallic lithium layer has a dense or porous structure.

11. The lithium-supplemented composite separator according to claim 1, characterized in that the material of the electronically conductive layer includes at least one of a metal, a metal oxide, a metal nitride, a metal sulfide, or a carbon material.

12. The aforementioned metallic material includes at least one of gold, silver, copper, iron, titanium, aluminum, manganese, tin, cobalt, nickel, chromium, bismuth, vanadium, molybdenum, or niobium. The lithium-supplemented composite separator according to claim 11, characterized in that the carbon material includes at least one of graphite, hard carbon, soft carbon, graphene, or carbon nanotubes.

13. The material of the second protective layer is Al ２ O ３ , MgO, ZnO ２ , TiO ２ , ZrO ２ , LaO ２ , CeO ２ , Y ２ O ３ , Si ｘ O, SiC, SiN ｘ , SiCN ｘ , AlN, Mg(OH) ２ , BaSO ４ , boehmite or perovskite, or, Li ２ CO ３ Li ３ N, LiF, Li ３ PO ４ Li ４ SiO ４ Li ４ Ti ５ O １２ , LiPON, LiSiON, LLZO, LLZTO, LATP, Li ３ Fe ２ (PO ４ ) ３ Li ３ V ２ (PO ４ ) ３ Li ３ In ２ (PO ４ ) ３ Li ３ Sc ２ (PO ４ ) ３ Li ３ Cr ２ (PO ４ ) ３ A lithium-replenished composite separator according to claim 2 or 3, characterized by comprising at least one of the following.

14. The lithium-replenished composite separator according to claim 1, characterized in that the separator layer is one of a base film, a base film / ceramic composite separator, a base film / adhesive composite separator, or a base film / ceramic / adhesive composite separator.

15. The base film includes at least one of the following: polyethylene base film, polyethylene nonwoven fabric base film, polypropylene base film, polypropylene nonwoven fabric base film, polypropylene / polyethylene / polypropylene composite base film, polyimide base film, polyimide nonwoven fabric base film, polytetrafluoroethylene base film, polytetrafluoroethylene nonwoven fabric base film, polyvinyl chloride base film, or polyvinyl chloride nonwoven fabric base film, and / or The ceramic comprises at least one of aluminum oxide, zirconium oxide, boehmite, magnesium hydroxide, barium sulfate, silicon oxide, aluminum nitride, magnesium oxide, titanium dioxide, yttrium oxide, or cerium oxide, and / or The lithium-supplemented composite separator according to claim 14, characterized in that the adhesive contains at least one of the following: polytetrafluoroethylene, polyvinylidene fluoride, acrylic acid, polyethylene oxide, sodium carboxymethylcellulose, styrene-butadiene rubber, hydroxypropyl methylcellulose, carboxystyrene-butadiene rubber, or polyvinyl alcohol.

16. The lithium-supplemented composite separator according to claim 1, characterized in that the metallic lithium layer contains at least one of metallic lithium, lithium silicon alloy, lithium tin alloy, lithium magnesium alloy, lithium copper alloy, lithium silver alloy, lithium beryllium alloy, lithium zinc alloy, lithium cadmium alloy, lithium aluminum alloy, lithium gold alloy, and lithium boron alloy.

17. A lithium battery comprising a lithium-replenished composite separator according to any one of claims 1 to 16, wherein the negative electrode layer comprises a negative electrode current collector layer and a negative electrode active material layer covering the negative electrode current collector layer, and the positive electrode layer comprises a positive electrode current collector layer and a positive electrode active material layer covering the positive electrode current collector layer.

18. The steps include providing a separator layer, The steps include forming a metallic lithium layer on one side of the separator layer, The steps include forming an electronically conductive layer on the surface of the metallic lithium layer, A method for manufacturing a lithium-replenished composite separator according to any one of claims 1 to 16, comprising the step of forming a first protective layer on the surface of the metallic lithium layer, wherein the orthographic projections of the electronically conductive layer and the first protective layer on the metallic lithium layer locally overlap.

19. Forming a metallic lithium layer on one side of the separator layer as described above means A second protective layer is formed on one side of the separator layer, The method according to 18, characterized in that it includes forming a metallic lithium layer on the surface of the second protective layer.

20. Forming a metallic lithium layer on one side of the separator layer as described above means A second protective layer is formed on one side of the separator layer, The method according to 18, characterized in that a metallic lithium layer is formed on the side of the separator layer opposite to the second protective layer.

21. The method for forming the second protective layer described above is: The method according to 19 or 20, characterized by comprising at least one of knife coating, roll coating, spray coating, gravure coating, extrusion coating, screen printing, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

22. The method according to 18, characterized in that the method for forming the electronically conductive layer includes at least one of knife coating, roll coating, spray coating, chemical vapor deposition, plasma vapor deposition, atomic layer deposition, pulsed laser deposition, vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

23. The method for forming the aforementioned lithium metallic layer is: The method according to 18, characterized by comprising at least one of vacuum deposition, ion plating, high-frequency sputtering, magnetron sputtering, or reactive sputtering.

24. A method for manufacturing a lithium battery, A step of manufacturing a lithium battery negative electrode, which includes a negative electrode current collector layer and a negative electrode active material layer covering the negative electrode current collector layer, A step of manufacturing a lithium battery positive electrode, which includes a positive electrode current collector layer and a positive electrode active material layer covering the positive electrode current collector layer, A step of manufacturing a lithium-replenished composite separator, wherein the method for manufacturing the lithium-replenished composite separator includes the step of employing the method described in any one of claims 18 to 23, A method for manufacturing a lithium battery, characterized by comprising the steps of assembling the lithium-replenished composite separator between the lithium battery negative electrode and the lithium battery positive electrode, and bonding the electronically conductive layer to the negative electrode active material layer.

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