Negative pole piece, battery monomer, battery device and power utilization device

Abstract

The invention provides a negative pole piece, a battery monomer, a battery device and a power utilization device, the negative pole piece comprises a negative current collector and an insulating framework positioned on at least one side of the negative current collector, and the insulating framework is provided with a plurality of pores; the negative pole piece further comprises a lithium-loving material, and the lithium-loving material is located on the surface, close to the insulation framework, of the negative pole current collector, and / or the lithium-loving material is located in a hole, close to the negative pole current collector, of the insulation framework. The negative pole piece is applied to the battery monomer, so that the battery monomer has relatively low volume expansion and good electrolyte wettability, and the battery monomer also has good cycle performance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a negative electrode tab, a battery cell, a battery device and a power utilization device. BACKGROUND

[0002] Battery cells using lithium metal as a negative electrode material have much higher energy density than lithium-ion battery cells, which is crucial for the realization of high-range electric vehicles, unmanned aerial vehicles, electric aircraft and other application scenarios. However, there is a problem of large volume expansion of the negative electrode during the charging and discharging process of the battery cell, which affects the electrochemical performance and practical application of the battery cell. SUMMARY

[0003] The present disclosure provides a negative electrode tab, a battery cell, a battery device and a power utilization device, which are applied to the battery cell, can make the battery cell have lower volume expansion and good electrolyte wettability, and can also make the battery cell have good cycle performance.

[0004] In a first aspect, the present disclosure provides a negative electrode tab, which comprises a negative electrode current collector and an insulating framework located on at least one side of the negative electrode current collector, the insulating framework having a plurality of pores; the negative electrode tab further comprises a lithiumophilic material, the lithiumophilic material being located on the surface of the negative electrode current collector close to the insulating framework, and / or the lithiumophilic material being located in the pores of the insulating framework close to the negative electrode current collector.

[0005] The framework of the negative electrode tab of the present disclosure is an insulating framework, which is not conductive and can better prevent lithium metal from being deposited and accumulated on the top of the insulating framework, and is also conducive to the preferential deposition of lithium metal on the bottom of the insulating framework, thereby better playing the role of the framework structure in relieving volume expansion. The negative electrode tab of the present disclosure further comprises a lithiumophilic material, which is located on the surface of the negative electrode current collector close to the insulating framework, and / or the lithiumophilic material is located in the pores of the insulating framework close to the negative electrode current collector, thereby making lithium ions first tend to be deposited on the surface of the negative electrode current collector and / or the bottom of the insulating framework. In addition, these lithiumophilic materials can further reduce the nucleation energy barrier of lithium metal, thereby also being conducive to adjusting the deposition morphology of lithium metal. The negative electrode tab of the present disclosure has a porous framework structure, and the insulating framework can provide large pores for electrolyte wettability, thereby enabling the electrolyte to be wetted to the middle of the battery cell, so as to reduce the probability of poor electrolyte wettability of the battery cell. Therefore, the negative electrode tab of the present disclosure is applied to the battery cell, can make the battery cell have lower volume expansion and good electrolyte wettability, and can also make the battery cell have good cycle performance.

[0006] In some embodiments, the lithiumophilic material comprises a lithiumophilic metal and / or a lithiumophilic alloy.

[0007] Thus, good electronic paths can be provided, and the nucleation energy barrier of lithium metal can be reduced, and the deposition morphology of lithium metal can be adjusted.

[0008] In some embodiments, the lithiumophilic material includes one or more of the elements Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge, and alloys thereof.

[0009] In some embodiments, the areal density of the lithiumophilic material located on the surface of the negative current collector near the insulating framework is 0.05 mg / cm 2 -1.5 mg / cm 2 .

[0010] In some embodiments, the areal density of the lithiumophilic material located in the pores of the insulating framework near the negative current collector is 0.02 mg / cm 2 -1 mg / cm 2 .

[0011] The areal density of the lithiumophilic material in the above range can reduce the nucleation energy barrier of lithium metal and adjust the deposition morphology of lithium metal without affecting the mechanical strength and tensile strength of the insulating framework.

[0012] In some embodiments, the thickness of the insulating framework is H, and the lithiumophilic material is located in the voids of the region extending 0.5H in the thickness direction of the insulating framework near the surface of the negative current collector.

[0013] Thus, it is beneficial for lithium metal to preferentially deposit at the bottom of the insulating framework, so that the framework structure can better alleviate the volume expansion.

[0014] In some embodiments, the negative electrode sheet further includes a lyophilic polymer having a lyophilic group, and the lyophilic polymer is located on the surface of the insulating framework and / or in the pores of the insulating framework.

[0015] Further providing a lyophilic polymer on the surface and / or pores of the insulating framework can improve the liquid binding capacity of the negative electrode sheet to the electrolyte, thereby facilitating the kinetic capacity of the battery cell to be better played, and also facilitating the volume irreversible expansion of the battery cell after multiple cycles to be alleviated.

[0016] Optionally, the lyophilic group includes one or more of a hydroxyl group, a carboxyl group, a carboxylate, and an amino group.

[0017] Optionally, the lyophilic polymer includes one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, and derivatives thereof.

[0018] In some embodiments, the insulating skeleton is made of an insulating material, and the areal density of the insulating material is 0.1 mg / cm³. 2 -10mg / cm 2 .

[0019] When the areal density of the insulating material is within the above range, the battery cell can have high volumetric energy density and high quality energy density.

[0020] In some embodiments, the thickness of the insulating skeleton is 10μm-700μm.

[0021] When the thickness of the insulating skeleton is within the above range, the battery cell can have high volumetric energy density and high quality energy density.

[0022] In some embodiments, the porosity of the insulating skeleton is greater than or equal to 80%.

[0023] In some embodiments, the insulating skeleton is a polymer fiber nonwoven fabric, a fiber skeleton, a foam polymer, or an aerogel.

[0024] In some embodiments, the polymer fiber nonwoven fabric is made of one or more of polyimide, polyvinylidene fluoride, polyacrylonitrile, polyethylene terephthalate, poly(p-phenylene terephthalate), polymethyl methacrylate, polyurethane, polystyrene, polyhexamethylene adipamide, polycaprolactam, polyetherimide, and their respective derivatives.

[0025] In some embodiments, the material of the fiber skeleton includes organic fibers, inorganic fibers, or organic-inorganic composite fibers.

[0026] Optionally, the fiber skeleton may be made of one or more of the following materials: glass fiber, ceramic fiber, metal oxide nanofiber, silica nanofiber, polyvinylidene fluoride fiber, polytetrafluoroethylene fiber, polyacrylonitrile fiber, aramid fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyethylene fiber, ultra-high molecular weight polyethylene fiber, polyvinyl chloride fiber, polypropylene fiber, polyvinylpyrrolidone fiber, polyurethane fiber, acetate fiber, polycaprolactone fiber, polylactic acid fiber, polyethersulfone fiber, polymethyl methacrylate fiber, polyethylene phthalate fiber, polyethylene terephthalate fiber, polyethylene terephthalate fiber, polyethylene naphthalate fiber, polyaniline fiber, SiO2 / polyvinylidene fluoride composite fiber, SiO2 / polyacrylonitrile composite fiber, Al2O3 / polyvinylidene fluoride composite fiber, and Al2O3 / polyacrylonitrile composite fiber.

[0027] In some embodiments, the foam polymer includes one or more of polyimide foam, polyethylene foam, polypropylene foam, polyurethane foam, polystyrene foam, melamine-formaldehyde foam, and polyvinyl alcohol foam.

[0028] In some embodiments, the aerogel includes organic aerogel, inorganic aerogel, or organic-inorganic aerogel.

[0029] Optionally, the aerogel includes one or more of the following: SiO2 aerogel, Al2O3 aerogel, TiO2 aerogel, wet-process glass fiber aerogel, pre-oxidized fiber aerogel, ceramic fiber aerogel, foam aerogel, non-woven fabric aerogel, phenolic aerogel, polyimide aerogel, cellulose aerogel, and chitosan aerogel.

[0030] Secondly, this disclosure provides a battery cell comprising a positive electrode, a separator, and a negative electrode, wherein the separator is located between the positive electrode and the negative electrode.

[0031] Thirdly, this disclosure provides a battery device comprising a plurality of battery cells as described in the second aspect.

[0032] Fourthly, this disclosure provides an electrical device that includes a battery cell as described in the second aspect or a battery device as described in the third aspect. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0034] Figure 1 A schematic diagram of a battery cell provided in some embodiments of this disclosure is shown.

[0035] Figure 2 A schematic diagram of an electrical device provided in some embodiments of this disclosure is shown.

[0036] Figure 3 The diagram shows a schematic representation of the negative electrode sheet provided in some embodiments of this disclosure.

[0037] Figure 4 A schematic diagram of the structure of the negative electrode sheet provided in some other embodiments of this disclosure is shown.

[0038] Figure 5 A schematic diagram of the structure of the negative electrode sheet provided in some embodiments of this disclosure is shown.

[0039] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0040] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the negative electrode, battery cell, battery assembly, and power-consuming device of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0041] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] Unless otherwise specified, all embodiments and optional embodiments of this disclosure may be combined with each other to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0043] Unless otherwise specified, all technical features and optional technical features of this disclosure can be combined to form new technical solutions, and such technical solutions should be considered as included in the disclosure of this disclosure.

[0044] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0045] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0046] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0047] In the description of the embodiments of this disclosure, unless otherwise specified, "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," "over," and "on top" of 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.

[0048] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0049] The battery cells mentioned in the embodiments of this disclosure are capable of charging and discharging independently. The battery cells may be cylindrical, cuboid, or other shapes, and this disclosure does not limit this. Figure 1 The example shown is a rectangular battery cell 5.

[0050] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0051] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0052] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0053] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0054] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0055] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0056] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0057] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0058] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0059] The technical solutions described in this disclosure are applicable to various electrical devices that use battery cells or battery devices, such as, but not limited to, mobile devices (e.g., mobile phones, tablets, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. Battery cells and battery devices are used to store or provide electrical energy.

[0060] Figure 2 This is a schematic diagram of an example electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0061] The battery cells provided in the embodiments of this disclosure can be negative electrode-free metal battery cells, such as negative electrode-free lithium metal battery cells.

[0062] A cathodeless lithium metal battery cell typically refers to a battery cell in which no negative electrode active material layer is actively placed on the negative electrode side during the battery cell manufacturing process. For example, during the manufacturing process, a layer of carbonaceous materials or similar negative electrode active material is not applied or deposited at the negative electrode. During the first charge, ions gain electrons on the negative electrode side and deposit on the surface of the negative electrode current collector to form lithium metal. During discharge, the lithium metal can be converted back into lithium ions and return to the positive electrode, achieving cycle charging and discharging. Compared to other battery cells, cathodeless lithium metal battery cells can achieve higher energy density due to the absence of a negative electrode active material layer.

[0063] Lithium metal possesses a high theoretical specific capacity (3860 mAh / g) and a low reduction potential (-3.04 V vs. SHE), making it a highly promising anode material. However, lithium metal anodes operate on a deposition / stripping mechanism during charge and discharge, causing repeated volume expansion and contraction of the battery cell. Furthermore, this often results in poor electrolyte wetting in the central area of ​​the cell. Therefore, the volume expansion and electrolyte wetting issues in lithium metal anode cells remain two major challenges for their commercialization.

[0064] Based on this, the present disclosure provides a negative electrode sheet that, when applied in a battery cell, enables the battery cell to have low volume expansion and good electrolyte wettability.

[0065] The negative electrode sheet disclosed herein includes a negative current collector and an insulating skeleton located on at least one side of the negative current collector, the insulating skeleton having a plurality of pores. The negative electrode sheet also includes a lithiophilic material located on the surface of the negative current collector near the insulating skeleton, and / or, the lithiophilic material located within the pores of the insulating skeleton near the negative current collector. The negative current collector has two surfaces opposite each other in its thickness direction, and the insulating skeleton is disposed on either or both of the two opposite surfaces of the negative current collector.

[0066] Currently, the framework set on the negative electrode current collector is a conductive framework. During the charging and discharging process of the battery cell, lithium metal tends to be deposited on the top of the conductive framework (i.e., the position away from the negative electrode current collector) rather than the middle and bottom. Therefore, as the battery cell is charged and discharged in cycles, lithium metal is continuously deposited and accumulated on the top of the conductive framework, which will still cause significant volume deformation of the negative electrode. This is not conducive to leveraging the advantage of the framework structure in alleviating the volume expansion of the negative electrode, nor is it conducive to improving the electrolyte wetting problem of the battery cell.

[0067] The negative electrode sheet disclosed herein has an insulating skeleton. The insulating skeleton is non-conductive, which can better prevent lithium metal from being deposited and accumulated on the top of the insulating skeleton, and also facilitates the preferential deposition of lithium metal at the bottom of the insulating skeleton. Thus, the skeleton structure can better play its role in mitigating volume expansion.

[0068] The negative electrode sheet disclosed herein also includes a lithiophilic material located on the surface of the negative electrode current collector near the insulating skeleton, and / or located within the pores of the insulating skeleton near the negative electrode current collector. This allows lithium ions to preferentially gain electrons on the surface of the negative electrode current collector and / or at the bottom of the insulating skeleton for deposition. Furthermore, these lithiophilic materials can further reduce the nucleation energy barrier of lithium metal, thereby also facilitating the regulation of lithium metal deposition morphology.

[0069] The negative electrode sheet disclosed herein has a porous skeleton structure. The insulating skeleton can provide large pores for electrolyte wetting, thereby allowing the electrolyte to wet the middle of the battery cell, which can reduce the probability of poor electrolyte wetting in the battery cell.

[0070] Therefore, when the negative electrode sheet of this disclosure is applied to a battery cell, it can enable the battery cell to have low volume expansion and good electrolyte wettability, as well as good cycle performance.

[0071] In some embodiments, the insulating skeleton is made of insulating material, and the areal density of the insulating material may be 0.1 mg / cm³. 2 -10mg / cm 2 For example, it can be 0.1 mg / cm³ 2 0.2 mg / cm 2 0.3 mg / cm 2 0.4 mg / cm 2 0.5 mg / cm 2 0.6 mg / cm 2 0.7 mg / cm 2 0.8 mg / cm 2 0.9 mg / cm 2 1mg / cm 2 1.1 mg / cm 2 1.2 mg / cm 2 1.3 mg / cm 2 1.4 mg / cm 2 1.5 mg / cm 2 1.6 mg / cm 2 1.7 mg / cm 2 1.8 mg / cm 2 1.9 mg / cm 2 2mg / cm 2 3mg / cm 2 4mg / cm 2 5mg / cm 2 6mg / cm 2 7mg / cm 2 8mg / cm2 9mg / cm 2 10mg / cm 2 or a range consisting of any of the above values.

[0072] When the areal density of the insulating material is within the above range, the battery cell can have high volumetric energy density and high quality energy density.

[0073] Optionally, the areal density of the insulating material can be 0.1 mg / cm³. 2 -7mg / cm 2 0.1 mg / cm 2 -5mg / cm 2 0.1 mg / cm 2 -3mg / cm 2 0.1 mg / cm 2 -1.5mg / cm 2 0.5 mg / cm 2 -7mg / cm 2 0.5 mg / cm 2 -5mg / cm 2 0.5 mg / cm 2 -3mg / cm 2 0.5 mg / cm 2 -1.5mg / cm 2 .

[0074] In some embodiments, the thickness of the insulating skeleton can be 10μm-700μm, for example, it can be 10μm, 20μm, 30μm, 40μm, 50μm, 75μm, 100μm, 125μm, 150μm, 175μm, 200μm, 225μm, 250μm, 275μm, 300μm, 325μm, 350μm, 375μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, or any range of the above values.

[0075] When the thickness of the insulating skeleton is within the above range, the battery cell can have high volumetric energy density and high quality energy density.

[0076] Optionally, the thickness of the insulating skeleton can be 20μm-700μm, 20μm-600μm, 20μm-500μm, 20μm-400μm, 20μm-300μm, 20μm-200μm, 40μm-700μm, 40μm-600μm, 40μm-500μm, 40μm-400μm, 40μm-300μm, 40μm-200μm, 50μm-700μm, 50μm-600μm, 50μm-500μm, 50μm-400μm, 50μm-300μm, or 50μm-200μm.

[0077] In some embodiments, the porosity of the insulating skeleton can be greater than or equal to 80%.

[0078] In some embodiments, the insulating skeleton may be a polymer fiber nonwoven fabric, a fiber skeleton, a foam polymer, or an aerogel.

[0079] In some embodiments, the material of the polymer fiber nonwoven fabric may include one or more of polyimide, polyvinylidene fluoride, polyacrylonitrile, polyethylene terephthalate, poly(p-phenylene terephthalamide), polymethyl methacrylate, polyurethane, polystyrene, polyhexamethylene adipamide, polycaprolactam, polyetherimide, and their respective derivatives. Derivatives refer to products derived from the substitution of hydrogen atoms or groups of atoms in the polymer by other atoms or groups of atoms.

[0080] A fiber skeleton refers to a framework formed by overlapping fiber materials. In some embodiments, the material of the fiber skeleton may include organic fibers, inorganic fibers, or organic-inorganic composite fibers.

[0081] Optionally, the material of the fiber skeleton may include one or more of the following: glass fiber, ceramic fiber, metal oxide nanofiber, silica nanofiber, polyvinylidene fluoride fiber, polytetrafluoroethylene fiber, polyacrylonitrile fiber, aramid fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyethylene fiber, ultra-high molecular weight polyethylene fiber, polyvinyl chloride fiber, polypropylene fiber, polyvinylpyrrolidone fiber, polyurethane fiber, acetate fiber, polycaprolactone fiber, polylactic acid fiber, polyethersulfone fiber, polymethyl methacrylate fiber, polyethylene phthalate fiber, polyethylene terephthalate fiber, polyethylene terephthalate fiber, polyethylene naphthalate fiber, polyaniline fiber, SiO2 / polyvinylidene fluoride composite fiber, SiO2 / polyacrylonitrile composite fiber, Al2O3 / polyvinylidene fluoride composite fiber, and Al2O3 / polyacrylonitrile composite fiber.

[0082] In some embodiments, the foam polymer may include one or more of polyimide foam, polyethylene foam, polypropylene foam, polyurethane foam, polystyrene foam, melamine-formaldehyde foam, and polyvinyl alcohol foam.

[0083] In some embodiments, the aerogel may include an organic aerogel, an inorganic aerogel, or an organic-inorganic aerogel.

[0084] Optionally, the aerogel may include one or more of the following: SiO2 aerogel, Al2O3 aerogel, TiO2 aerogel, wet-process glass fiber aerogel, pre-oxidized fiber aerogel, ceramic fiber aerogel, foam aerogel, non-woven fabric aerogel, phenolic aerogel, polyimide aerogel, cellulose aerogel, and chitosan aerogel.

[0085] In some embodiments, the lithiophilic material may include a lithiophilic metal and / or a lithiophilic alloy.

[0086] This provides a good electronic pathway and can also reduce the nucleation energy barrier of lithium metal and regulate the deposition morphology of lithium metal.

[0087] Optionally, the lithiophilic material may include one or more of elemental Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge and their alloys.

[0088] In some embodiments, the negative electrode may further include a hydrophilic polymer having hydrophilic groups, and the hydrophilic polymer may be located on the surface of the insulating skeleton and / or within the pores of the insulating skeleton.

[0089] Further placing a hydrophilic polymer on the surface and / or within the pores of the insulating skeleton can enhance the liquid binding ability of the negative electrode to the electrolyte, thereby improving the dynamic capacity of the battery cell and mitigating the irreversible volume expansion of the battery cell after multiple cycles.

[0090] The insulating skeleton can be a polymer fiber nonwoven fabric, fiber skeleton, foam polymer or aerogel. The hydrophilic polymer can be located on the surface of the insulating skeleton along the thickness direction, or in the voids of the insulating skeleton, for example, it can be located on the fiber surface or the surface of the pore wall, or it can be located on both the surface of the insulating skeleton and in the voids of the insulating skeleton.

[0091] Optionally, the hydrophilic polymer can be located both on the surface of the insulating skeleton and within the pores of the insulating skeleton.

[0092] In some embodiments, the hydrophilic group may include one or more of hydroxyl, carboxyl, carboxyl, and amino groups.

[0093] In some embodiments, the hydrophilic polymer may include one or more of polyethylene oxide (PEO), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polymethacrylic acid, sodium polyacrylate, and their respective derivatives. A derivative is a product derived from the substitution of hydrogen atoms or groups of atoms in the polymer by other atoms or groups of atoms.

[0094] Figures 3 to 5 A schematic diagram of the structure of the negative electrode 10 provided in some embodiments of this disclosure is shown.

[0095] like Figure 3 As shown, the negative electrode 10 includes a negative current collector 11, an insulating skeleton 12 located on one side of the negative current collector 11, and a lithium-loving material 13, which is located on the surface of the negative current collector 11 near the insulating skeleton 12.

[0096] In some embodiments, the lithium-loving material 13 can be formed on the surface of the negative electrode current collector 11 near the insulating skeleton 12 by processes such as vapor deposition, vapor deposition (e.g., magnetron sputtering).

[0097] like Figure 4 As shown, the negative electrode 10 includes a negative current collector 11, an insulating framework 12 located on one side of the negative current collector 11, and a lithiophilic material 13, the lithiophilic material 13 being located within the pores of the insulating framework 12 near the negative current collector 11. Figure 4 In the figure, the insulating skeleton 12 is composed of an insulating skeleton with a lithium-loving material and an insulating skeleton without a lithium-loving material. Reference numeral 13 can also be considered as an insulating skeleton with a lithium-loving material.

[0098] Optionally, the negative electrode 10 may further include a hydrophilic polymer located on the surface of the insulating skeleton 12 and / or within the pores of the insulating skeleton 12. Figure 4 (Not shown).

[0099] In some embodiments, the lithium-loving material 13 can be formed in the pores of the insulating skeleton 12 near the negative electrode current collector 11 by processes such as vapor deposition or vapor deposition (e.g., magnetron sputtering).

[0100] like Figure 5 As shown, the negative electrode 10 includes a negative current collector 11, an insulating skeleton 12 located on one side of the negative current collector 11, and a lithium-loving material 13. The lithium-loving material 13 is located on the surface of the negative current collector 11 near the insulating skeleton 12 and in the pores of the insulating skeleton 12 near the negative current collector 11.

[0101] Optionally, the negative electrode 10 may further include a hydrophilic polymer located on the surface of the insulating skeleton 12 and / or within the pores of the insulating skeleton 12. Figure 5 (Not shown).

[0102] In some embodiments, the lithiophilic material may be located simultaneously on the surface of the negative electrode current collector near the insulating skeleton and within the pores of the insulating skeleton near the negative electrode current collector.

[0103] This allows the insulating framework and the negative electrode current collector to be integrated during the lithium metal deposition process, thereby improving the structural stability of the negative electrode and reducing the interfacial impedance of the battery cell.

[0104] In some embodiments, the lithiophilic material is located in the pores of the insulating skeleton near the negative electrode current collector, or the lithiophilic material is simultaneously located on the surface of the negative electrode current collector near the insulating skeleton and in the pores of the insulating skeleton near the negative electrode current collector. In this case, the thickness of the insulating skeleton is H, and the lithiophilic material is located in the voids of the region of the insulating skeleton extending 0.5H from the surface near the negative electrode current collector along the thickness direction.

[0105] This facilitates the preferential deposition of lithium metal at the bottom of the insulating framework, thereby allowing the framework structure to better mitigate volume expansion.

[0106] Optionally, the lithiophilic material is located in the voids of the insulating skeleton in a region extending 0.25H along the thickness direction from the surface near the negative electrode current collector.

[0107] Alternatively, the lithiophilic material is located within the voids of the insulating framework in a region extending 0.1H along the thickness direction from the surface near the negative electrode current collector.

[0108] In some embodiments, the lithiophilic material is located on the surface of the negative electrode current collector near the insulating skeleton, or the lithiophilic material is simultaneously located on the surface of the negative electrode current collector near the insulating skeleton and within the pores of the insulating skeleton near the negative electrode current collector. In this case, the areal density of the lithiophilic material located on the surface of the negative electrode current collector near the insulating skeleton can be 0.05 mg / cm³. 2 -1.5mg / cm 2 For example, it can be 0.05 mg / cm³. 2 0.06 mg / cm 2 0.08 mg / cm 2 0.1 mg / cm 2 0.2 mg / cm 2 0.3 mg / cm 2 0.4 mg / cm 2 0.5 mg / cm 2 0.6 mg / cm 2 0.7 mg / cm 2 0.8 mg / cm 2 0.9 mg / cm 2 1mg / cm 2 1.1 mg / cm 2 1.2 mg / cm2 1.3 mg / cm 2 1.4 mg / cm 2 1.5 mg / cm 2 or a range consisting of any of the above values.

[0109] Optionally, the areal density of the lithiophilic material located on the surface of the negative electrode current collector near the insulating framework can be 0.05 mg / cm³. 2 -1mg / cm 2 0.05 mg / cm 2 -0.8mg / cm 2 0.05 mg / cm 2 -0.6mg / cm 2 0.05 mg / cm 2 -0.4mg / cm 2 0.1 mg / cm 2 -1mg / cm 2 0.1 mg / cm 2 -0.8mg / cm 2 0.1 mg / cm 2 -0.6mg / cm 2 0.1 mg / cm 2 -0.4mg / cm 2 .

[0110] In some embodiments, the lithiophilic material is located within the pores of the insulating framework near the negative electrode current collector, or the lithiophilic material is simultaneously located on the surface of the negative electrode current collector near the insulating framework and within the pores of the insulating framework near the negative electrode current collector. In this case, the areal density of the lithiophilic material located within the pores of the insulating framework near the negative electrode current collector can be 0.02 mg / cm³. 2 -1mg / cm 2 For example, it could be 0.02 mg / cm³. 2 0.04 mg / cm 2 0.06 mg / cm 2 0.08 mg / cm 2 0.1 mg / cm 2 0.2 mg / cm 2 0.3 mg / cm 2 0.4 mg / cm 2 0.5 mg / cm 2 0.6 mg / cm 2 0.7 mg / cm 2 0.8 mg / cm 2 0.9 mg / cm 2 1mg / cm 2or a range consisting of any of the above values.

[0111] Within the above-mentioned range, the areal density of lithiophilic materials can reduce the nucleation energy barrier of lithium metal and adjust the deposition morphology of lithium metal without affecting the mechanical strength and tensile strength of the insulating skeleton.

[0112] Optionally, the areal density of the lithiophilic material located in the pores of the insulating framework near the negative electrode current collector can be 0.02 mg / cm³. 2 -0.8mg / cm 2 0.02 mg / cm 2 -0.6mg / cm 2 0.02 mg / cm 2 -0.4mg / cm 2 0.02 mg / cm 2 -0.3mg / cm 2 0.04 mg / cm 2 -0.8mg / cm 2 0.04 mg / cm 2 -0.6mg / cm 2 0.04 mg / cm 2 -0.4mg / cm 2 0.04 mg / cm 2 -0.3mg / cm 2 0.06 mg / cm 2 -0.8mg / cm 2 0.06 mg / cm 2 -0.6mg / cm 2 0.06 mg / cm 2 -0.4mg / cm 2 0.06 mg / cm 2 -0.3mg / cm 2 .

[0113] The areal density of lithiophilic materials can be measured using inductively coupled plasma atomic emission spectrometry (ICP).

[0114] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include copper foil, copper alloy foil, nickel foil, nickel alloy foil, aluminum foil, and aluminum alloy foil. The composite current collector may include a polymer substrate and a metal material layer formed on at least one surface of the polymer substrate. Examples of metal materials include, but are not limited to, one or more of copper, copper alloys, aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymer substrates include, but are not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0115] This disclosure also provides a battery cell, which includes an electrode assembly, an electrolyte, and an outer packaging.

[0116] The electrode assembly includes a positive electrode, a separator, and a negative electrode as disclosed herein, with the separator located between the positive and negative electrodes.

[0117] The outer packaging is used to contain the electrode assembly and electrolyte. The outer packaging can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. It can also be a flexible package, such as a pouch. The flexible package can be made of plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0118] [Positive electrode plate]

[0119] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer located on at least one surface of the positive current collector, the positive electrode film layer including a positive active material. The positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0120] In some embodiments, the positive electrode active material may include one or more of lithium transition metal oxides and their modified forms, lithium phosphates and their modified forms.

[0121] Optionally, examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and lithium-rich manganese-based materials.

[0122] Optionally, examples of lithium phosphates may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0123] In some embodiments, to further improve the energy density of a single battery cell, the positive electrode active material may include materials of the general formula Li. a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified materials. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M may include one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A may include one or more of N, F, S and Cl.

[0124] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.83 Mn 0.08 Co 0.07 O2 (abbreviated as Ni83), LiNi 0.90 Mn 0.05 Co 0.05 O2 (abbreviated as Ni90), LiNi 0.94 Mn 0.03 Co 0.03 O2 (abbreviated as Ni94), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 One or more of O2, LiFePO4, LiMnPO4 and their respective modified materials.

[0125] During the charging and discharging process, lithium (Li) undergoes insertion / extraction and consumption within a single battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before material addition. As the positive electrode active material is applied to the battery cell, the molar Li content changes after charge-discharge cycles. Similarly, the molar O content in the examples of positive electrode active materials in this disclosure is only a theoretical value. Oxygen release from the crystal lattice causes changes in the molar O content, leading to fluctuations in the actual molar O content.

[0126] The modified materials for the above-mentioned positive electrode active materials can be the positive electrode active materials through doping modification and / or surface coating modification.

[0127] In some embodiments, the positive electrode film layer may further include a positive electrode binder, which may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0128] In some embodiments, the positive electrode film may further include a positive electrode conductive agent, which may include, but is not limited to, one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers, and vapor-grown carbon fibers (VGCF).

[0129] In some embodiments, the positive current collector may be a metal foil or a composite current collector. Examples of metal foils include carbon-coated aluminum foil, aluminum foil, nickel foil, and titanium foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. Examples of metal materials include, but are not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymer substrates include, but are not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0130] [Isolation membrane]

[0131] The separator is located between the positive and negative electrodes, primarily serving to prevent internal short circuits. This application does not impose any particular limitation on the type of separator; any known porous membrane with good chemical and mechanical stability can be selected. In some embodiments, the separator material may include, but is not limited to, one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The separator can be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different.

[0132] [Electrolytes]

[0133] Electrolytes play a role in conducting ions between the positive and negative electrodes.

[0134] In some embodiments, the electrolyte may be a liquid electrolyte, i.e., an electrolyte solution. An electrolyte solution includes an electrolyte salt and a solvent.

[0135] In some embodiments, the electrolyte salt may be one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0136] In some embodiments, the solvent may include, but is not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0137] In some embodiments, the electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve overcharge performance, additives that improve high-temperature performance, additives that improve low-temperature performance, etc.

[0138] Methods for preparing battery cells are well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a battery cell. As an example, the positive electrode, the separator, and the negative electrode can be assembled into an electrode assembly, which is then placed in an outer packaging, dried, injected with electrolyte, and subjected to standing and other processes to obtain a battery cell.

[0139] Example

[0140] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0141] Example 1

[0142] Preparation of the positive electrode sheet

[0143] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, polyvinylidene fluoride (PVDF) as the positive electrode binder, and acetylene black as the positive electrode conductive agent are mixed in a mass ratio of 98:1:1, and N-methylpyrrolidone is added and stirred to form a uniform positive electrode slurry. The positive electrode slurry is then uniformly coated on both surfaces of the positive electrode current collector aluminum foil, with a positive electrode active material loading of 25 mg / cm³. 2 After drying and cold pressing, the material is then cut into rectangular electrodes of 40mm×50mm as positive electrodes.

[0144] Preparation of the negative electrode sheet

[0145] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0146] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0147] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0148] Separator film

[0149] Porous polypropylene membrane is used as the separator.

[0150] Preparation of the electrolyte

[0151] The electrolyte solvent is a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7, and the lithium salt is lithium hexafluorophosphate (LiPF6) with a concentration of 1 mol / L. The electrolyte injection volume is 0.3 g.

[0152] Preparation of the battery cell

[0153] One cut positive electrode sheet and two negative electrode sheets are matched, and two separator films are placed between the positive and negative electrodes to isolate them to obtain an electrode assembly. Then, electrode tabs are welded, and the electrode assembly is placed in an outer packaging aluminum-plastic film. After that, electrolyte is injected and vacuum hot-pressed for sealing. After standing for 8 hours, a battery cell is obtained with a rated capacity of 140mAh.

[0154] Example 2

[0155] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0156] Preparation of the negative electrode sheet

[0157] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0158] A 70 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0159] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0160] Example 3

[0161] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0162] Preparation of the negative electrode sheet

[0163] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0164] A 40 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0165] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0166] Example 4

[0167] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0168] Preparation of the negative electrode sheet

[0169] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time.2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0170] A 100 μm thick polyvinylidene fluoride membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. Then it was taken out and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyvinylidene fluoride membrane modified with the hydrophilic polymer PEG-400.

[0171] A polyvinylidene fluoride membrane modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyvinylidene fluoride membrane and the copper foil. The resulting sheet was then cut into rectangular pieces of 42 mm × 52 mm to serve as the negative electrode.

[0172] Example 5

[0173] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0174] Preparation of the negative electrode sheet

[0175] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0176] A 100 μm thick glass fiber membrane was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then removed and dried in an oven until the DMSO was completely evaporated, to obtain a glass fiber membrane modified with the hydrophilic polymer PEG-400.

[0177] A glass fiber membrane modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the glass fiber membrane and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0178] Example 6

[0179] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0180] Preparation of the negative electrode sheet

[0181] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.1 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0182] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0183] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0184] Example 7

[0185] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0186] Preparation of the negative electrode sheet

[0187] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.4 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0188] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0189] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0190] Example 8

[0191] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0192] Preparation of the negative electrode sheet

[0193] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.05 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0194] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0195] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0196] Example 9

[0197] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0198] Preparation of the negative electrode sheet

[0199] The negative electrode current collector copper foil and the metallic bismuth target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Bi was adjusted to 0.3 mg / cm³ by adjusting the sputtering time. 2 Open the chamber to obtain copper foil modified with the lithium-loving metal Bi.

[0200] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0201] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil modified with the lithium-philic metal Bi were stacked together, with the lithium-philic metal Bi positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0202] Example 10

[0203] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0204] Preparation of the negative electrode sheet

[0205] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0206] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PVA-1788 dimethyl sulfoxide (DMSO) solution for 5 min. Then it was removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PVA-1788.

[0207] A polyacrylonitrile film modified with the hydrophilic polymer PVA-1788 and a copper foil modified with the lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting product was then cut into rectangular sheets of 42 mm × 52 mm to serve as the negative electrode.

[0208] Example 11

[0209] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0210] Preparation of the negative electrode sheet

[0211] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0212] A 100 μm thick polyacrylonitrile film prepared by electrospinning and a copper foil modified with lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn positioned between the polyacrylonitrile film and the copper foil. The resulting sheet was then cut into rectangular pieces of 42 mm × 52 mm to serve as the negative electrode.

[0213] Example 12

[0214] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0215] Preparation of the negative electrode sheet

[0216] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the container to obtain copper foil modified with the lithium-loving metal Zn.

[0217] A 70 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0218] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a zinc target were placed in a magnetron sputtering system, and the vacuum was evacuated to 6 × 10⁻⁶. -4 After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 Open the chamber to obtain a polyacrylonitrile membrane modified with lithium-loving metal Zn and hydrophilic polymer PEG-400.

[0219] A polyacrylonitrile film modified with lithium-philic metal Zn and PEG-400 and a copper foil modified with lithium-philic metal Zn were stacked together, with the lithium-philic metal Zn on the polyacrylonitrile film facing each other and the lithium-philic metal Zn on the copper foil. The film was then cut into rectangular sheets of 42mm×52mm as negative electrode sheets.

[0220] Comparative Example 1

[0221] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0222] Preparation of the negative electrode sheet

[0223] The copper foil was cut into rectangular sheets of 42mm × 52mm to serve as the negative electrode sheet.

[0224] Comparative Example 2

[0225] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0226] Preparation of the negative electrode sheet

[0227] The negative electrode current collector copper foil and the metallic zinc target are placed in the magnetron sputtering system, and the vacuum is evacuated to 6×10⁻⁶. -4After Pa, argon gas was introduced, followed by DC sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the areal density of Zn was adjusted to 0.2 mg / cm³ by adjusting the sputtering time. 2 The chamber was opened to obtain copper foil modified with the lithium-loving metal Zn, which was then cut into rectangular sheets of 42mm×52mm as negative electrode sheets.

[0228] Comparative Example 3

[0229] Except for the following differences, the preparation method of the battery cell is the same as that in Example 1.

[0230] Performance test

[0231] A 100 μm thick polyacrylonitrile membrane prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min. It was then removed and placed in an oven to dry until the DMSO was completely evaporated, thus obtaining a polyacrylonitrile membrane modified with the hydrophilic polymer PEG-400.

[0232] A polyacrylonitrile film modified with the hydrophilic polymer PEG-400 and a copper foil for the negative electrode current collector are stacked together and then cut into rectangular sheets of 42mm×52mm as the negative electrode sheet.

[0233] ​

[0234] The battery cells were cycled at 25°C using a 0.2C (28mA) charge and a 1C (140mA) discharge. During the test, a constant pressure of 0.5 MPa (109.2 kg) was applied to the battery cells using an in-situ expansion tester.

[0235] Specifically, the battery cells are charged at a constant current rate of 0.2C to 4.3V, followed by constant voltage charging until the current decays to 0.15C; then discharged at a constant current rate of 1C to a voltage of 2.8V, obtaining the initial discharge capacity; subsequently, the above steps are repeated for charge-discharge cycles. The capacity retention rate after 100 cycles = discharge capacity after 100 cycles / initial discharge capacity × 100%.

[0236] The thickness of a single battery cell before the cycle test is denoted as H1, and the thickness of a single battery cell after 100 cycles and complete discharge (0% SOC) is denoted as H2. Irreversible volume expansion after 100 cycles = H2 - H1.

[0237] Table 1

[0238]

[0239] The test results above show that the negative electrode sheet disclosed herein can enable the battery cell to have high first-cycle discharge capacity, high cycle capacity retention rate and low volume expansion.

[0240] The test results from Examples 1 to 12 and Comparative Example 2 also show that the insulating skeleton disclosed herein can improve electrolyte wettability and alleviate polarization from the first cycle of the battery cell, thereby improving the dynamic capacity of the battery cell. Furthermore, the insulating skeleton can also alleviate the irreversible volume expansion of the battery cell after multiple cycles.

[0241] The test results from Examples 1 to 12 and Comparative Example 3 also show that the insulating skeleton can improve the first-cycle discharge capacity of the battery cell and reduce the irreversible volume expansion of the battery cell after multiple cycles. However, since the negative electrode sheet of Comparative Example 3 does not contain lithium-loving materials, it cannot play a role in mitigating side reactions and uniform lithium metal deposition morphology, which leads to a sharp decrease in the capacity retention rate of the battery cell after multiple cycles.

[0242] The test results from Examples 1 to 3 also show that further adjusting the thickness of the insulating skeleton can further improve the capacity retention rate of the battery cell after multiple cycles and alleviate the irreversible volume expansion of the battery cell after multiple cycles.

[0243] The test results from Examples 1, 6 to 8 also show that further adjusting the areal density of the lithium-loving material can further improve the capacity retention rate of the battery cell after multiple cycles and alleviate the irreversible volume expansion of the battery cell after multiple cycles.

[0244] The test results of Examples 1 and 11 also show that setting a hydrophilic polymer on the surface and in the gaps of the insulating skeleton can enhance the liquid binding effect of the negative electrode sheet, which is beneficial to improving the dynamic capacity of the battery cell and also helps to alleviate the irreversible volume expansion of the battery cell after multiple cycles.

[0245] The test results from Examples 1 and 12 also show that the lithiophilic material is located on both the copper foil and within the pores of the polyacrylonitrile film. During the lithium metal deposition process, the polyacrylonitrile film and the copper foil can be integrated, which improves the structural stability of the negative electrode and reduces the interfacial impedance of the battery cell. This can further improve the capacity retention rate of the battery cell after multiple cycles and further alleviate the irreversible volume expansion of the battery cell after multiple cycles.

[0246] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this disclosure are included within the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included within the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A negative electrode sheet, characterized by, The negative electrode tab comprises a negative electrode current collector and an insulating framework located on at least one side of the negative electrode current collector, the insulating framework having a plurality of pores; the negative electrode tab further comprises a lithiumophilic material, the lithiumophilic material being located on the surface of the negative electrode current collector close to the insulating framework and / or the lithiumophilic material being located in the pores of the insulating framework close to the negative electrode current collector.

2. The negative electrode sheet according to claim 1, characterized by The lithiumophilic material comprises a lithiumophilic metal and / or a lithiumophilic alloy.

3. The negative electrode sheet according to any one of claims 1 to 2, wherein The lithiumophilic material comprises one or more of the elements Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge and alloys thereof.

4. The negative electrode sheet according to any one of claims 1 to 3, wherein The areal density of the lithium-philic material on the surface of the negative current collector near the insulating skeleton is 0.05 mg / cm 2 -1.5 mg / cm 2 .

5. The negative electrode sheet according to any one of claims 1 to 4, wherein The areal density of the lithiumophilic material located within the porosity of the insulating skeleton, close to the negative current collector is 0.02 mg / cm 2 -1 mg / cm 2 .

6. The negative electrode sheet according to any one of claims 1 to 5, wherein The thickness of the insulating framework is H, and the lithiumophilic material is located in the pores of the insulating framework in the region extending 0.5H in the thickness direction from the surface close to the negative electrode current collector.

7. The negative electrode sheet according to any one of claims 1 to 6, wherein The negative electrode tab further comprises a lyophilic polymer, the lyophilic polymer having a lyophilic group, the lyophilic polymer being located on the surface of the insulating framework and / or in the pores of the insulating framework.

8. The negative electrode sheet according to claim 7, characterized by The lyophilic group comprises one or more of a hydroxyl group, a carboxyl group, a carboxylate, and an amino group.

9. The negative electrode sheet according to any one of claims 7 to 8, wherein The lyophilic polymer comprises one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, and derivatives thereof.

10. The negative electrode tab of any one of claims 1-9, wherein: The insulating skeleton is composed of an insulating material, and the areal density of the insulating material is 0.1 mg / cm 2 - 10 mg / cm 2 ; and / or, the thickness of the insulating framework is 10-700 μm; and / or the porosity of the insulating framework is greater than or equal to 80%.

11. The negative electrode sheet according to any one of claims 1 to 10, wherein The insulating framework is a polymer fiber non-woven fabric, a fiber framework, a foamed polymer, or an aerogel.

12. The negative electrode tab of claim 11, wherein: the material of the polymer fiber non-woven fabric comprises one or more of polyimide, polyvinylidene fluoride, polyacrylonitrile, polyethylene terephthalate, polyphenylene terephthalamide, polymethyl methacrylate, polyurethane, polystyrene, polyhexamethylene adipamide, polycaprolactam, polyetherimide, and derivatives thereof; and / or the material of the fiber framework comprises organic fibers, inorganic fibers, or organic-inorganic composite fibers; and / or the foamed polymer comprises one or more of polyimide foam, polyethylene foam, polypropylene foam, polyurethane foam, polystyrene foam, melamine formaldehyde foam, and polyvinyl alcohol foam; and / or the aerogel comprises organic aerogels, inorganic aerogels, or organic-inorganic aerogels.

13. The negative electrode tab of claim 12, wherein: The material of the fiber skeleton includes one or more of glass fiber, ceramic fiber, metal oxide nanofiber, silica nanofiber, polyvinylidene fluoride fiber, polytetrafluoroethylene fiber, polyacrylonitrile fiber, aramid fiber, polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyethylene fiber, ultra-high molecular weight polyethylene fiber, polyvinyl chloride fiber, polypropylene fiber, polyvinylpyrrolidone fiber, polyurethane fiber, acetate fiber, polycaprolactone fiber, polylactic acid fiber, polyether sulfone fiber, polymethyl methacrylate fiber, polyethylene terephthalate fiber, polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene terephthalate fiber, polyaniline fiber, SiO2 / polyvinylidene fluoride composite fiber, SiO2 / polyacrylonitrile composite fiber, Al2O3 / polyvinylidene fluoride composite fiber, Al2O3 / polyacrylonitrile composite fiber, and / or, The aerogel includes one or more of SiO2 aerogel, Al2O3 aerogel, TiO2 aerogel, wet-process glass fiber aerogel, pre-oxidized fiber aerogel, ceramic fiber aerogel, foam aerogel, non-woven fabric aerogel, phenolic aerogel, polyimide aerogel, cellulose aerogel, and chitosan aerogel.

14. A battery cell, characterized by The battery device includes a positive electrode sheet, a separator film, and a negative electrode sheet according to any one of claims 1-13, wherein the separator film is located between the positive electrode sheet and the negative electrode sheet.

15. A battery device characterized by comprising: The battery device includes a plurality of battery cells according to claim 14.

16. An electrical device, comprising: The battery device includes a battery cell according to claim 14 or a battery device according to claim 15.

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