Negative electrode pole piece, battery cell, battery apparatus, and electrical apparatus

Abstract

Provided in the present disclosure are a negative electrode pole piece, a battery cell, a battery apparatus, and an electrical apparatus. The negative electrode pole piece comprises a negative electrode current collector and an insulating frame located on at least one side of the negative electrode current collector. The insulating frame has a plurality of gaps. The negative electrode pole piece further comprises a lithiophilic material. The lithiophilic material is located on the surface of the negative electrode current collector close to the insulating frame, and / or the lithiophilic material is located in the gaps of the insulating frame close to the negative electrode current collector. The negative electrode pole piece is used in the battery cell, can enable the battery cell to have low volume expansion and good electrolyte wettability, and also enable the battery cell to have good cycle performance.

Description

Negative electrode sheet, battery cell, battery device, and electric device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411343170.X, filed on September 25, 2024, entitled “Negative electrode sheet, battery cell, battery device, and electric device,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a negative electrode sheet, a battery cell, a battery device, and an electric device. BACKGROUND

[0004] Battery cells using lithium metal as a negative electrode material have an energy density much higher than that of lithium-ion battery cells, which is crucial for the realization of high-endurance electric vehicles, unmanned aerial vehicles, electric aircraft, and other application scenarios. However, there is a problem of large negative electrode volume expansion during the charging and discharging process of the battery cell, which affects its electrochemical performance and practical application. SUMMARY

[0005] The present disclosure provides a negative electrode sheet, a battery cell, a battery device, and an electric device. The negative electrode sheet is applied to the battery cell, which can make the battery cell have lower volume expansion and good electrolyte wettability, and also make the battery cell have good cycle performance.

[0006] In a first aspect, the present disclosure provides a negative electrode sheet, which includes 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 sheet further includes 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.

[0007] The skeleton of the negative electrode tab of the present disclosure is an insulating skeleton, which is not conductive, can better prevent lithium metal from depositing and accumulating on the top of the insulating skeleton, and is also conducive to the preferential deposition of lithium metal on the bottom of the insulating skeleton, thereby better exerting the role of the skeleton structure in relieving volume expansion. The negative electrode tab of the present disclosure also includes lithiumophilic materials, which are located on the surface of the negative electrode current collector near the insulating skeleton and / or are located in the pores of the insulating skeleton near the negative electrode current collector, thereby enabling lithium ions to first tend to be deposited by obtaining electrons on the surface of the negative electrode current collector and / or the bottom of the insulating skeleton; in addition, these lithiumophilic materials can further reduce the nucleation energy barrier of lithium metal, thereby also being conducive to regulating the deposition morphology of lithium metal. The negative electrode tab of the present disclosure has a porous skeleton structure, and the insulating skeleton can provide large pores for electrolyte infiltration, thereby enabling the electrolyte to infiltrate to the middle of the battery monomer, so as to reduce the probability of the battery monomer having a poor electrolyte infiltration problem. Therefore, the negative electrode tab of the present disclosure applied to the battery monomer can enable the battery monomer to have lower volume expansion and good electrolyte infiltration, and also enable the battery monomer to have good cycle performance.

[0008] In some embodiments, the lithiumophilic material includes a lithiumophilic metal and / or a lithiumophilic alloy.

[0009] Thereby, 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 regulated.

[0010] In some embodiments, the lithiumophilic material includes one or more of the elemental substances of Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge and alloys thereof.

[0011] In some embodiments, the areal density of the lithiumophilic material located on the surface of the negative electrode current collector near the insulating skeleton is 0.05 mg / cm 2 -1.5 mg / cm 2 .

[0012] In some embodiments, the areal density of the lithiumophilic material located in the pores of the insulating skeleton near the negative electrode current collector is 0.02 mg / cm 2 -1 mg / cm 2 .

[0013] The areal density of the lithiumophilic material within the above range can reduce the nucleation energy barrier of lithium metal and regulate the deposition morphology of lithium metal without affecting the mechanical strength and tensile strength of the insulating skeleton.

[0014] In some embodiments, the thickness of the insulating skeleton is H, and the lithiumophilic material is located in the voids of a region extending 0.5H in the thickness direction from the surface of the insulating skeleton near the negative electrode current collector.

[0015] Thus, it is beneficial for the lithium metal to be preferentially deposited at the bottom of the insulating framework, so that the role of the framework structure in relieving volume expansion can be better played.

[0016] In some embodiments, the negative electrode tab further comprises a lyophilic polymer having lyophilic groups, the lyophilic polymer being located on the surface of the insulating framework and / or within the pores of the insulating framework.

[0017] Further providing the lyophilic polymer on the surface and / or within the pores of the insulating framework can improve the lyophobicity of the negative electrode tab to the electrolyte, thereby being beneficial for improving the kinetic capacity performance of the battery cell and also being beneficial for relieving the volume irreversible expansion of the battery cell after multiple cycles.

[0018] Optionally, the lyophilic groups comprise one or more of hydroxyl groups, carboxyl groups, carboxylate groups, and amino groups.

[0019] Optionally, the lyophilic polymer comprises one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, and respective derivatives thereof.

[0020] In some embodiments, the insulating framework is composed of an insulating material, and the areal density of the insulating material is 0.1 mg / cm 2 - 10 mg / cm 2 .

[0021] The areal density of the insulating material within the above range can enable the battery cell to have high volumetric energy density and high mass energy density.

[0022] In some embodiments, the thickness of the insulating framework is 10 μm-700 μm.

[0023] The thickness of the insulating framework within the above range can enable the battery cell to have high volumetric energy density and high mass energy density.

[0024] In some embodiments, the porosity of the insulating framework is greater than or equal to 80%.

[0025] In some embodiments, the insulating framework is a polymer fiber non-woven fabric, a fiber framework, a foamed polymer, or an aerogel.

[0026] In some embodiments, 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 respective derivatives thereof.

[0027] In some embodiments, the material of the fiber skeleton comprises organic fibers, inorganic fibers, or organic-inorganic composite fibers.

[0028] Optionally, the material of the fiber skeleton comprises one or more of glass fibers, ceramic fibers, metal oxide nanofibers, silica nanofibers, polyvinylidene fluoride fibers, polytetrafluoroethylene fibers, polyacrylonitrile fibers, aramid fibers, polyester fibers, polyamide fibers, polyvinyl alcohol fibers, polyethylene fibers, ultra-high molecular weight polyethylene fibers, polyvinyl chloride fibers, polypropylene fibers, polyvinylpyrrolidone fibers, polyurethane fibers, acetate fibers, polycaprolactone fibers, polylactic acid fibers, polyethersulfone fibers, polymethyl methacrylate fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, polyaniline fibers, SiO2 / polyvinylidene fluoride composite fibers, SiO2 / polyacrylonitrile composite fibers, Al2O3 / polyvinylidene fluoride composite fibers, Al2O3 / polyacrylonitrile composite fibers.

[0029] In some embodiments, the foam polymer comprises one or more of polyimide foam, polyethylene foam, polypropylene foam, polyurethane foam, polystyrene foam, melamine formaldehyde foam, polyvinyl alcohol foam.

[0030] In some embodiments, the aerogel comprises organic aerogels, inorganic aerogels, or organic-inorganic aerogels.

[0031] Optionally, the aerogel comprises 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, chitosan aerogel.

[0032] In a second aspect, the present disclosure provides a battery cell comprising a positive electrode sheet, a separator film, and the negative electrode sheet of the first aspect, the separator film being located between the positive electrode sheet and the negative electrode sheet.

[0033] In a third aspect, the present disclosure provides a battery device comprising a plurality of the battery cells of the second aspect.

[0034] In a fourth aspect, the present disclosure provides an electrically powered device comprising the battery cell of the second aspect or the battery device of the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed to be used in the embodiments of the present disclosure will be briefly introduced. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the drawings.

[0036] FIG. 1 shows a schematic diagram of a battery cell according to some embodiments of the present disclosure.

[0037] FIG. 2 shows a schematic diagram of a power consumption device according to some embodiments of the present disclosure.

[0038] FIG. 3 shows a schematic diagram of a negative electrode tab according to some embodiments of the present disclosure.

[0039] FIG. 4 shows a schematic diagram of a negative electrode tab according to some other embodiments of the present disclosure.

[0040] FIG. 5 shows a schematic diagram of a negative electrode tab according to some other embodiments of the present disclosure.

[0041] In the drawings, the drawings are not necessarily drawn according to the actual scale. DETAILED DESCRIPTION

[0042] Hereinafter, specific embodiments of the negative electrode tab, the battery cell, the battery device and the power consumption device of the present disclosure will be described in detail with appropriate reference to the drawings. However, there will be cases where unnecessary detailed description is omitted. For example, there will be cases where detailed description of matters known well, repeated description of substantially the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided in order for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0043] The ranges disclosed herein are defined by their lower and upper endpoints, given that a range is defined by selecting a lower endpoint and an upper endpoint, the selected lower and upper endpoints define the boundaries of the particular range. Ranges defined by endpoints can be either inclusive or exclusive without further qualification. Ranges formed by combining the lower and upper endpoint of these described ranges are also contemplated; for example, a range from 60-120 and a range from 80-110, are understood to include a range from 60-110, as well as a range from 80-120. Also, a range from 1-2 and a range from 3-5, are understood to include a range from 1-5, as well as a range from 2-3. In this disclosure, unless otherwise stated, a numerical range "a-b" indicates a shorthand way of describing all real numbers between a and b, inclusive of a and b. For example, the numerical range "0-5" indicates that all real numbers between 0 and 5, inclusive of 0 and 5, have been listed herein. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and the like.

[0044] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0045] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0046] Unless otherwise specified, all steps of the present disclosure can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0047] Unless otherwise specified, in the present disclosure, the terms "first", "second", and the like are used to distinguish different objects, and are not used to describe a particular order or primary and secondary relationship.

[0048] In the present disclosure, the terms "a plurality of", "a plurality of" refer to two or more.

[0049] In the description of the embodiments of the present disclosure, if there is no special indication, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be "above", "over" and "on" the second feature, which can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature can be "below", "under" and "under" the second feature, which can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0050] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25°C.

[0051] The battery cell mentioned in the embodiments of the present disclosure can realize the function of charging and discharging independently. The battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the embodiments of the present disclosure. As shown in FIG. 1, the battery cell 5 is a cuboid structure as an example.

[0052] The battery apparatus mentioned in the embodiments of the present disclosure can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, in parallel or in a mixed manner through a busbar component.

[0053] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells.

[0054] As an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0055] In some embodiments, the battery apparatus can be a battery pack, which includes a box body and one or more battery cell assemblies accommodated in the box body.

[0056] As an example, the battery cell assembly can be a battery module, which can be accommodated in the box body by fixing the battery module in the box body.

[0057] As an example, the battery cell assembly can also be accommodated in the box body by directly fixing a plurality of battery cells in the box body.

[0058] As an example, the case can include a first case and a second case. The first case and the second case are fastened so that an inner part of the case forms a closed space to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0059] As an example, the case can include a top cover, a frame and a bottom plate. The top cover and the bottom plate are connected with the frame respectively so that an inner part of the case forms a closed space to accommodate the battery cell assembly.

[0060] In some embodiments, the case can be part of a chassis structure of a vehicle. For example, part of the case can be at least part of a floor of the vehicle, or part of the case can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0061] The technical solutions described in the embodiments of the present disclosure are applicable to various electric devices using battery cells and battery devices, such as mobile devices (e.g., mobile phones, tablet computers, notebook computers, 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, unmanned aerial vehicles, electric aircrafts, energy storage systems, etc. The battery cells and battery devices are used to store or provide electric energy.

[0062] FIG. 2 is a schematic diagram of an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0063] The battery cell provided by the embodiments of the present disclosure can be a negative electrode-free metal battery cell, such as a negative electrode-free lithium metal battery cell, etc.

[0064] The negative electrode-free lithium metal battery cell generally refers to a battery cell that is not actively provided with a negative electrode active material layer on the negative electrode side during the manufacturing process of the battery cell, such as a battery cell that is not provided with a negative electrode active material layer formed of a carbonaceous material by coating or deposition, etc. at the negative electrode during the manufacturing process of the battery cell. During the first charging, ions obtain electrons on the negative electrode side and deposit to form lithium metal on the surface of the negative electrode current collector. During discharging, the lithium metal can be converted into lithium ions to return to the positive electrode, realizing cyclic charging and discharging. Compared with other battery cells, the negative electrode-free lithium metal battery cell can obtain higher energy density because of the absence of the negative electrode active material layer.

[0065] Lithium metal has a high theoretical specific capacity (3860 mAh / g) and a low reduction potential (-3.04 V vs. SHE), and thus is a promising anode material. Lithium metal anode is a deposition / stripping mechanism during the charge / discharge process, which causes the battery cell to face repeated volume expansion and contraction. In addition, the middle part of the battery cell is usually affected by poor electrolyte wettability. Therefore, the volume expansion and electrolyte wettability of the battery cell using lithium metal as the anode material are still two major problems in its commercialization.

[0066] Based on this, the present disclosure provides an anode sheet applied in a battery cell, which can make the battery cell have lower volume expansion and good electrolyte wettability.

[0067] The anode sheet of the present disclosure includes an anode current collector and an insulating framework located on at least one side of the anode current collector, and the insulating framework has a plurality of pores. The anode sheet further includes a lithiumophilic material, which is located on the surface of the anode current collector close to the insulating framework, and / or the lithiumophilic material is located in the pores of the insulating framework close to the anode current collector. The anode current collector has two opposite surfaces in the thickness direction of itself, and the insulating framework is arranged on any one or both of the two opposite surfaces of the anode current collector.

[0068] Currently, the framework arranged on the anode current collector is a conductive framework. During the charge / discharge process of the battery cell, lithium metal is more likely to be deposited on the top of the conductive framework (i.e., away from the anode current collector) rather than the middle and bottom, and thus lithium metal continuously deposits and accumulates on the top of the conductive framework as the battery cell cycles charge / discharge, which still causes the anode to have obvious volume deformation, which is not conducive to taking advantage of the framework structure to alleviate the volume expansion of the anode, nor to improve the electrolyte wettability of the battery cell.

[0069] The framework of the anode sheet of the present disclosure is an insulating framework, which is not conductive, can better prevent lithium metal from depositing and accumulating on the top of the insulating framework, and is also conducive to lithium metal preferentially depositing on the bottom of the insulating framework, thereby better taking advantage of the framework structure to alleviate the volume expansion.

[0070] The anode sheet of the present disclosure further includes a lithiumophilic material, which is located on the surface of the anode current collector close to the insulating framework, and / or the lithiumophilic material is located in the pores of the insulating framework close to the anode current collector, thereby making lithium ions first tend to deposit by obtaining electrons on the surface of the anode 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.

[0071] The negative electrode tab of the present disclosure has a porous framework structure, and the insulating framework can provide large pores for electrolyte infiltration, thereby enabling the electrolyte to infiltrate into the middle of the battery cell, and thus reducing the probability of electrolyte infiltration problems in the battery cell.

[0072] Therefore, the negative electrode tab of the present disclosure applied to the battery cell can make the battery cell have lower volume expansion and good electrolyte infiltration, and also make the battery cell have good cycle performance.

[0073] In some embodiments, the insulating framework is composed of an insulating material, and the area density of the insulating material can be 0.1 mg / cm 2 -10 mg / cm 2 , for example, can be 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 , 1 mg / 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 , 2 mg / cm 2 , 3 mg / cm 2 , 4 mg / cm 2 , 5 mg / cm 2 , 6 mg / cm 2 , 7 mg / cm 2 , 8 mg / cm 2 , 9 mg / cm 2 , 10 mg / cm 2 , or a range composed of any of the above values.

[0074] The area density of the insulating material in the above range can make the battery cell have high volume energy density and high mass energy density.

[0075] Alternatively, the area density of the insulating material can be 0.1 mg / cm2 -7 mg / cm 2 , 0.1 mg / cm 2 -5 mg / cm 2 , 0.1 mg / cm 2 -3 mg / cm 2 , 0.1 mg / cm 2 -1.5 mg / cm 2 , 0.5 mg / cm 2 -7 mg / cm 2 , 0.5 mg / cm 2 -5 mg / cm 2 , 0.5 mg / cm 2 -3 mg / cm 2 , 0.5 mg / cm 2 -1.5 mg / cm 2 .

[0076] In some embodiments, the thickness of the insulating skeleton can be 10 pm to 700 pm, for example, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 75 pm, 100 pm, 125 pm, 150 pm, 175 pm, 200 pm, 225 pm, 250 pm, 275 pm, 300 pm, 325 pm, 350 pm, 375 pm, 400 pm, 450 pm, 500 pm, 550 pm, 600 pm, 650 pm, 700 pm, or a range defined by any of the above values.

[0077] The thickness of the insulating skeleton in the above range can allow the battery cell to have high volumetric energy density and high mass energy density.

[0078] Alternatively, the thickness of the insulating skeleton can be 20 pm to 700 pm, 20 pm to 600 pm, 20 pm to 500 pm, 20 pm to 400 pm, 20 pm to 300 pm, 20 pm to 200 pm, 40 pm to 700 pm, 40 pm to 600 pm, 40 pm to 500 pm, 40 pm to 400 pm, 40 pm to 300 pm, 40 pm to 200 pm, 50 pm to 700 pm, 50 pm to 600 pm, 50 pm to 500 pm, 50 pm to 400 pm, 50 pm to 300 pm, 50 pm to 200 pm.

[0079] In some embodiments, the porosity of the insulating skeleton can be greater than or equal to 80%.

[0080] In some embodiments, the insulating skeleton can be a polymeric fiber nonwoven fabric, a fiber skeleton, a foamed polymer, or an aerogel.

[0081] In some embodiments, the material of the polymeric fiber nonwoven fabric can include one or more of polyimide, polyvinylidene fluoride, polyacrylonitrile, polyethylene terephthalate, poly(p-phenylene terephthalamide), polymethyl methacrylate, polyurethane, polystyrene, poly(hexamethylene adipamide), polycaprolactam, polyetherimide, and derivatives of each thereof. Derivatives refer to products derived from substitution of hydrogen atoms or groups in the polymers with other atoms or groups.

[0082] The fiber skeleton refers to a skeleton formed by lapping of fiber materials. In some embodiments, the material of the fiber skeleton can include organic fibers, inorganic fibers, or organic-inorganic composite fibers.

[0083] Optionally, the material of the fiber skeleton can include one or more of glass fibers, ceramic fibers, metal oxide nanofibers, silica nanofibers, polyvinylidene fluoride fibers, polytetrafluoroethylene fibers, polyacrylonitrile fibers, aramid fibers, polyester fibers, polyamide fibers, polyvinyl alcohol fibers, polyethylene fibers, ultra-high molecular weight polyethylene fibers, polyvinyl chloride fibers, polypropylene fibers, polyvinylpyrrolidone fibers, polyurethane fibers, acetate fibers, polycaprolactone fibers, polylactic acid fibers, polyethersulfone fibers, polymethyl methacrylate fibers, polyethylene terephthalate fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, polyaniline fibers, SiO2 / polyvinylidene fluoride composite fibers, SiO2 / polyacrylonitrile composite fibers, Al2O3 / polyvinylidene fluoride composite fibers, Al2O3 / polyacrylonitrile composite fibers.

[0084] In some embodiments, the foam polymer can include one or more of polyimide foam, polyethylene foam, polypropylene foam, polyurethane foam, polystyrene foam, melamine formaldehyde foam, polyvinyl alcohol foam.

[0085] In some embodiments, the aerogel can include organic aerogels, inorganic aerogels, or organic-inorganic aerogels.

[0086] Optionally, the aerogel can include one or more of SiO2 aerogel, Al2O3 aerogel, TiO2 aerogel, wet-process glass fiber aerogel, pre-oxidized fiber aerogel, ceramic fiber aerogel, foam aerogel, nonwoven fabric aerogel, phenolic aerogel, polyimide aerogel, cellulose aerogel, chitosan aerogel.

[0087] In some embodiments, the lithiumophilic material can include lithiumophilic metals and / or lithiumophilic alloys.

[0088] In this way, not only can good electronic paths be provided, but also the nucleation energy barrier of lithium metal can be reduced, and the deposition morphology of lithium metal can be adjusted.

[0089] Optionally, the lithiumophilic material can include one or more of the elements Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge and alloys thereof.

[0090] In some embodiments, the negative electrode tab can further include a lithiumophilic polymer having a lithiumophilic group, which can be located on the surface of the insulating framework and / or within the pores of the insulating framework.

[0091] Further providing the lithiumophilic polymer on the surface and / or within the pores of the insulating framework can improve the lithium absorption capacity of the negative electrode tab to the electrolyte, thereby facilitating the kinetic capacity release of the battery cell and also facilitating the relief of the volume irreversible expansion of the battery cell after multiple cycles.

[0092] The insulating framework can be a polymer fiber non-woven fabric, a fiber framework, a foamed polymer or an aerogel, and the lithiumophilic polymer can be located on the surface of the insulating framework along the thickness direction, within the pores of the insulating framework, for example, on the surface of the fibers or the pore walls, or both on the surface of the insulating framework and within the pores of the insulating framework.

[0093] Optionally, the lithiumophilic polymer can be located both on the surface of the insulating framework and within the pores of the insulating framework.

[0094] In some embodiments, the lithiumophilic group can include one or more of a hydroxyl group, a carboxyl group, a carboxylate, and an amino group.

[0095] In some embodiments, the lithiumophilic polymer can include one or more of polyethylene oxide (PEO), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polymethacrylic acid, sodium polyacrylate, and derivatives thereof. The derivative refers to a product derived from the substitution of a hydrogen atom or a group in a polymer with another atom or group.

[0096] FIGS. 3-5 show structural schematic diagrams of the negative electrode tab 10 according to some embodiments of the present disclosure.

[0097] As shown in FIG. 3, the negative electrode tab 10 includes a negative current collector 11, an insulating framework 12 located on one side of the negative current collector 11, and a lithiumophilic material 13 located on the surface of the negative current collector 11 close to the insulating framework 12.

[0098] In some embodiments, the lithiumophilic material 13 can be formed on the surface of the negative current collector 11 close to the insulating framework 12 by processes such as evaporation, vapor deposition (e.g., magnetron sputtering), etc.

[0099] As shown in FIG. 4, the negative electrode tab 10 includes a negative electrode current collector 11, an insulating framework 12 located on one side of the negative electrode current collector 11, and a lithiumophilic material 13 located in the pores of the insulating framework 12 close to the negative electrode current collector 11. In FIG. 4, the insulating framework 12 is composed of an insulating framework with a lithiumophilic material and an insulating framework without a lithiumophilic material, and the reference sign 13 can also be considered as an insulating framework with a lithiumophilic material.

[0100] Optionally, the negative electrode tab 10 can further include a lithiumophilic polymer located on the surface of the insulating framework 12 and / or in the pores of the insulating framework 12 (not shown in FIG. 4).

[0101] In some embodiments, the lithiumophilic material 13 can be formed in the pores of the insulating framework 12 close to the negative electrode current collector 11 by processes such as evaporation, vapor deposition (e.g., magnetron sputtering), etc.

[0102] As shown in FIG. 5, the negative electrode tab 10 includes a negative electrode current collector 11, an insulating framework 12 located on one side of the negative electrode current collector 11, and a lithiumophilic material 13 located on the surface of the insulating framework 12 close to the negative electrode current collector 11 and in the pores of the insulating framework 12 close to the negative electrode current collector 11.

[0103] Optionally, the negative electrode tab 10 can further include a lithiumophilic polymer located on the surface of the insulating framework 12 and / or in the pores of the insulating framework 12 (not shown in FIG. 5).

[0104] In some embodiments, the lithiumophilic material can be located on the surface of the insulating framework close to the negative electrode current collector and in the pores of the insulating framework close to the negative electrode current collector.

[0105] In this way, the insulating framework and the negative electrode current collector can be integrated during the deposition of lithium metal, thereby improving the structural stability of the negative electrode and reducing the interface impedance of the battery cell.

[0106] In some embodiments, the lithiumophilic material is located in the pores of the insulating framework close to the negative electrode current collector, or the lithiumophilic material is located on the surface of the insulating framework close to the negative electrode current collector and in the pores of the insulating framework close to the negative electrode current collector, and in this case, the thickness of the insulating framework is H, and the lithiumophilic material is located in the pores of the region of the insulating framework extending 0.5H in the thickness direction from the surface close to the negative electrode current collector.

[0107] In this way, it is beneficial for the lithium metal to preferentially deposit at the bottom of the insulating framework, thereby better exerting the role of the framework structure in relieving volume expansion.

[0108] Optionally, the lithiumophilic material is located in the pores of the region of the insulating framework extending 0.25H in the thickness direction from the surface close to the negative electrode current collector.

[0109] More optionally, the lithiumophilic material is located in the void of the region of the insulating skeleton extending 0.1H in the thickness direction from the surface of the negative current collector.

[0110] In some embodiments, the lithiumophilic material is located on the surface of the negative current collector close to the insulating skeleton, or the lithiumophilic material is located on the surface of the negative current collector close to the insulating skeleton and in the void of the insulating skeleton close to the negative current collector at the same time, in which case the areal density of the lithiumophilic material located on the surface of the negative current collector close to the insulating skeleton can be 0.05 mg / cm 2 -1.5 mg / cm 2 , for example, can be 0.05 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 , 1 mg / 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 , or a range composed of any of the above values.

[0111] Optionally, the areal density of the lithiumophilic material located on the surface of the negative current collector close to the insulating skeleton can be 0.05 mg / cm 2 -1 mg / cm 2 , 0.05 mg / cm 2 -0.8 mg / cm 2 , 0.05 mg / cm 2 -0.6 mg / cm 2 , 0.05 mg / cm 2 -0.4 mg / cm 2 , 0.1 mg / cm 2 -1 mg / cm 2 , 0.1 mg / cm 2 -0.8 mg / cm 2 , 0.1 mg / cm 2 -0.6 mg / cm 20.1 mg / cm 2 -0.4 mg / cm 2 .

[0112] In some embodiments, the lithiumophilic material is located in the pores of the insulating skeleton near the negative current collector, or the lithiumophilic material is located on the surface of the negative current collector near the insulating skeleton and in the pores of the insulating skeleton near the negative current collector, and in this case, the areal density of the lithiumophilic material located in the pores of the insulating skeleton near the negative current collector can be 0.02 mg / cm 2 -1 mg / cm 2 , for example, can be 0.02 mg / cm 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 , 1 mg / cm 2 , or a range composed of any of the above values.

[0113] 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 skeleton.

[0114] Optionally, the areal density of the lithiumophilic material located in the pores of the insulating skeleton near the negative current collector can be 0.02 mg / cm 2 -0.8 mg / cm 2 , 0.02 mg / cm 2 -0.6 mg / cm 2 , 0.02 mg / cm 2 -0.4 mg / cm 2 , 0.02 mg / cm 2 -0.3 mg / cm 2 , 0.04 mg / cm 2 -0.8 mg / cm 2 , 0.04 mg / cm 2 -0.6 mg / cm 2 , 0.04 mg / cm 2 -0.4 mg / cm2 0.04 mg / cm 2 -0.3 mg / cm 2 0.06 mg / cm 2 -0.8 mg / cm 2 0.06 mg / cm 2 -0.6 mg / cm 2 0.06 mg / cm 2 -0.4 mg / cm 2 0.06 mg / cm 2 -0.3 mg / cm 2 .

[0115] The areal density of the lithium-philic material can be tested by inductively coupled plasma optical emission spectroscopy (ICP).

[0116] In some embodiments, the negative current collector can be a metal foil or a composite current collector. As examples of the metal foil, copper foil, copper alloy foil, nickel foil, nickel alloy foil, aluminum foil, and aluminum alloy foil can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As examples, the metal material can include, but is not limited to, one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As examples, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0117] The present disclosure also provides a battery cell including an electrode assembly, an electrolyte, and an outer package.

[0118] The electrode assembly includes a positive electrode sheet, a separator, and the negative electrode sheet of the present disclosure, the separator being between the positive electrode sheet and the negative electrode sheet.

[0119] The outer package is for containing the electrode assembly and the electrolyte. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft pack, such as a pouch-type soft pack. The soft pack can be made of plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0120] [Positive electrode sheet]

[0121] In some embodiments, the positive electrode sheet can include a positive current collector and a positive film layer on at least one surface of the positive current collector, the positive film layer including a positive active material. The positive current collector has two surfaces opposite in the thickness direction of itself, and the positive film layer is disposed on either one or both of the two opposite surfaces of the positive current collector.

[0122] In some embodiments, the positive active material can include one or more of lithium transition metal oxides and modified materials thereof, lithium-containing phosphates and modified materials thereof.

[0123] Optionally, examples of the lithium transition metal oxides can include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium-rich manganese-based materials.

[0124] Optionally, examples of the lithium-containing phosphates can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon.

[0125] In some embodiments, to further enhance the energy density of the battery cell, the positive active material can include one or more of lithium transition metal oxides and modified materials thereof having a general formula of Li a Ni b Co c M d O e A f 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M can include one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A can include one or more of N, F, S, and Cl.

[0126] As examples, the positive active material can include, but are not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2(referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2(referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(referred to as NCM811), LiNi 0.83 Mn 0.08 Co 0.07O2(simplified as Ni83), LiNi 0.90 Mn 0.05 Co 0.05 O2(simplified as Ni90), LiNi 0.94 Mn 0.03 Co 0.03 O2(simplified as Ni94), LiNi 0.96 Co 0.02 Mn 0.02 O2(simplified as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, and their respective modified materials.

[0127] The battery cell will be accompanied by Li de-intercalation and consumption during charging and discharging, and the molar content of Li is different when the battery cell is discharged to different states. In the enumeration of the positive electrode active material in the present disclosure, the molar content of Li is the initial state of the material, i.e., the state before feeding, and the positive electrode active material is applied to the battery cell. After charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive electrode active material in the present disclosure, the molar content of O is only the theoretical state value, and the lattice oxygen release will cause the molar content of O to change, and the actual molar content of O will also appear to float.

[0128] The modified material of each of the above positive electrode active materials can be a doping modification and / or a surface coating modification of the positive electrode active material.

[0129] In some embodiments, the positive electrode film layer can further include a positive electrode binder, which can include but is not limited to one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorine-containing acrylic ester resin.

[0130] In some embodiments, the positive electrode film layer can further include a positive electrode conductive agent, which can include but is not limited to one or more of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, carbon nanofibers, vapor grown carbon fiber (VGCF).

[0131] In some embodiments, the positive current collector can be a metal foil or a composite current collector. As examples of metal foils, carbon-coated aluminum foil, aluminum foil, nickel foil, titanium foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As examples, the metal material can include, but is not limited to, one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As examples, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene.

[0132] [Separator]

[0133] The separator is located between the positive electrode sheet and the negative electrode sheet and mainly functions to prevent internal short circuit. The type of the separator is not particularly limited in the present application, and any publicly known porous structure film having good chemical stability and mechanical stability can be selected. In some embodiments, the material of the separator can include, but is not limited to, one or more of glass fiber, non-woven 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 the layers can be the same or different.

[0134] [Electrolyte]

[0135] The electrolyte functions to conduct ions between the positive and negative electrodes.

[0136] In some embodiments, the electrolyte can employ a liquid electrolyte, i.e., electrolytic solution. The electrolytic solution includes an electrolyte salt and a solvent.

[0137] In some embodiments, the electrolyte salt can include, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), lithium bisoxalato borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalato phosphate (LiDFOP), and lithium tetrafluorodioxalato phosphate (LiTFOP).

[0138] In some embodiments, the solvent can include, but is not limited to, one or more of 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), butylene 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, crown ether.

[0139] In some embodiments, an additive can also be included in the electrolyte. For example, the additive can include a negative electrode film-forming additive, can also include a positive electrode film-forming additive, and can further include an additive capable of improving certain performance of the battery cell, such as an additive for improving overcharge performance, an additive for improving high-temperature performance, an additive for improving low-temperature performance, and the like.

[0140] Methods for preparing battery cells are well known. In some embodiments, a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte can be assembled to form a battery cell. As an example, a positive electrode sheet, a separator, and a negative electrode sheet can be assembled into an electrode assembly, the electrode assembly can be placed in an outer package, and after drying, an electrolyte can be injected, and the battery cell can be obtained after processes such as standing.

[0141] Embodiments

[0142] The following examples more specifically describe the present disclosure, which are merely illustrative and not limiting, as various modifications and changes in the aspects specifically recited herein can occur to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported herein are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used without further purification, and the instruments used in the examples are commercially available.

[0143] Example 1

[0144] Preparation of a positive electrode sheet

[0145] A positive active material LiNi 0.8 Co 0.1 Mn 0.1O2, positive electrode binder polyvinylidene fluoride (PVDF), positive electrode conductive agent acetylene black are mixed in a mass ratio of 98:1:1, and N-methyl pyrrolidone is added for stirring to form a uniform positive electrode slurry; the positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, and the loading of the positive electrode active material is 25 mg / cm 2 , and then dried, cold-pressed, and cut into 40 mm x 50 mm rectangular electrode pieces as positive electrode pieces.

[0146] Preparation of negative electrode pieces

[0147] The negative electrode current collector copper foil and the metal zinc target are placed in a magnetron sputtering system, the vacuum is pumped to 6 x 10 -4 Pa, argon gas is introduced, and then direct current sputtering is performed; the sputtering power is 60 W, and the sputtering pressure is 0.8 Pa; the surface density of Zn is adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber is opened to obtain the copper foil modified with the lithiumophilic metal Zn.

[0148] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning is completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO is completely volatilized to obtain the polyacrylonitrile film modified with the lyophilic polymer PEG-400.

[0149] The polyacrylonitrile film modified with the lyophilic polymer PEG-400 and the copper foil modified with the lithiumophilic metal Zn are stacked with the lithiumophilic metal Zn located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular piece with a size of 42 mm x 52 mm as a negative electrode piece.

[0150] Separator film

[0151] A porous polypropylene film is used as the separator film.

[0152] Preparation of electrolyte

[0153] The solvent of the electrolyte is a mixed solvent of ethylene carbonate (EC) and methyl ethyl 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 injection amount of the electrolyte is 0.3 g.

[0154] Preparation of battery monomer

[0155] The cut positive electrode piece and the two negative electrode pieces are matched, and two separator films are added between the positive and negative electrodes to isolate the positive and negative electrodes to obtain an electrode assembly, and then the tabs are welded. The electrode assembly is placed in an outer packaging aluminum plastic film, and then the electrolyte is injected and vacuum hot-pressed and packaged. After standing for 8 h, the battery monomer is obtained, and the rated capacity of the battery monomer is 140 mAh.

[0156] Example 2

[0157] The preparation method of the battery monomer was the same as that of Example 1, except for the following differences.

[0158] Preparation of the negative electrode tab

[0159] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6x10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the copper foil modified with the lithiumophilic metal Zn was obtained.

[0160] The polyacrylonitrile film prepared by electrospinning and having a thickness of 70 μm was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain the polyacrylonitrile film modified with the lyophilic polymer PEG-400.

[0161] The polyacrylonitrile film modified with the lyophilic polymer PEG-400 and the copper foil modified with the lithiumophilic metal Zn were superimposed, and the lithiumophilic metal Zn was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as the negative electrode tab.

[0162] Example 3

[0163] The preparation method of the battery monomer was the same as that of Example 1, except for the following differences.

[0164] Preparation of the negative electrode tab

[0165] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6x10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the copper foil modified with the lithiumophilic metal Zn was obtained.

[0166] The polyacrylonitrile film prepared by electrospinning and having a thickness of 40 μm was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain the polyacrylonitrile film modified with the lyophilic polymer PEG-400.

[0167] The PEG-400 modified polyacrylonitrile membrane and the lithium-philic metal Zn modified copper foil were stacked with the lithium-philic metal Zn between the polyacrylonitrile membrane and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0168] Example 4

[0169] The method for preparing the battery cell was the same as that in Example 1 except for the following differences.

[0170] Preparation of a negative electrode sheet

[0171] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the lithium-philic metal Zn modified copper foil was obtained.

[0172] The polyvinylidene fluoride membrane with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain the PEG-400 modified polyvinylidene fluoride membrane.

[0173] The PEG-400 modified polyvinylidene fluoride membrane and the lithium-philic metal Zn modified copper foil were stacked with the lithium-philic metal Zn between the polyvinylidene fluoride membrane and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0174] Example 5

[0175] The method for preparing the battery cell was the same as that in Example 1 except for the following differences.

[0176] Preparation of a negative electrode sheet

[0177] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the lithium-philic metal Zn modified copper foil was obtained.

[0178] The glass fiber membrane with a thickness of 100 μm was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain a lyophilic polymer PEG-400 modified glass fiber membrane.

[0179] The lyophilic polymer PEG-400 modified glass fiber membrane and the lithiumophilic metal Zn modified copper foil were stacked with the lithiumophilic metal Zn located between the glass fiber membrane and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0180] Example 6

[0181] The preparation method of the battery cell was the same as that in Example 1, except for the following differences.

[0182] Preparation of a negative electrode sheet

[0183] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.1 mg / cm 2 by adjusting the sputtering time, and the chamber was opened to obtain a lithiumophilic metal Zn modified copper foil.

[0184] The polyacrylonitrile membrane with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain a lyophilic polymer PEG-400 modified polyacrylonitrile membrane.

[0185] The lyophilic polymer PEG-400 modified polyacrylonitrile membrane and the lithiumophilic metal Zn modified copper foil were stacked with the lithiumophilic metal Zn located between the polyacrylonitrile membrane and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0186] Example 7

[0187] The preparation method of the battery cell was the same as that in Example 1, except for the following differences.

[0188] Preparation of a negative electrode sheet

[0189] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.1 mg / cm 2; open the chamber to obtain the lithium-philic metal Zn modified copper foil.

[0190] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized to obtain a lithium-philic polymer PEG-400 modified polyacrylonitrile film.

[0191] The lithium-philic polymer PEG-400 modified polyacrylonitrile film and the lithium-philic metal Zn modified copper foil were superimposed, and the lithium-philic metal Zn was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0192] Example 8

[0193] The preparation method of the battery monomer was the same as that in Example 1, except for the following differences.

[0194] Preparation of a negative electrode sheet

[0195] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.05 mg / cm 2 ; the chamber was opened to obtain the lithium-philic metal Zn modified copper foil.

[0196] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized to obtain a lithium-philic polymer PEG-400 modified polyacrylonitrile film.

[0197] The lithium-philic polymer PEG-400 modified polyacrylonitrile film and the lithium-philic metal Zn modified copper foil were superimposed, and the lithium-philic metal Zn was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0198] Example 9

[0199] The preparation method of the battery monomer was the same as that in Example 1, except for the following differences.

[0200] Preparation of a negative electrode sheet

[0201] The negative electrode current collector copper foil and the metal bismuth target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4After the pressure was stabilized at 0.8 Pa, argon was introduced, followed by direct current sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Bi was adjusted to 0.3 mg / cm2by adjusting the sputtering time. 2 The copper foil was opened, and the lithiumophilic metal Bi-modified copper foil was obtained.

[0202] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain a lithiumophilic polymer PEG-400-modified polyacrylonitrile film.

[0203] The lithiumophilic polymer PEG-400-modified polyacrylonitrile film and the lithiumophilic metal Bi-modified copper foil were stacked, and the lithiumophilic metal Bi was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0204] Example 10

[0205] The preparation method of the battery monomer was the same as that in Example 1, except for the following differences.

[0206] Preparation of a negative electrode sheet

[0207] The negative electrode current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, followed by direct current sputtering; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm2by adjusting the sputtering time. 2 The copper foil was opened, and the lithiumophilic metal Zn-modified copper foil was obtained.

[0208] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PVA-1788 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain a lithiumophilic polymer PVA-1788-modified polyacrylonitrile film.

[0209] The lithiumophilic polymer PVA-1788-modified polyacrylonitrile film and the lithiumophilic metal Zn-modified copper foil were stacked, and the lithiumophilic metal Zn was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0210] Example 11

[0211] The preparation method of the battery monomer was the same as that in Example 1, except for the following differences.

[0212] Preparation of a negative electrode sheet

[0213] The negative current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6x10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the copper foil modified with the lithiumophilic metal Zn was obtained.

[0214] The polyacrylonitrile film prepared by electrospinning with a thickness of 100 pm and the copper foil modified with the lithiumophilic metal Zn were stacked, and the lithiumophilic metal Zn was located between the polyacrylonitrile film and the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0215] Example 12

[0216] The preparation method of the battery monomer was the same as that in Example 1, except for the following differences.

[0217] Preparation of the negative electrode sheet

[0218] The negative current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6x10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the copper foil modified with the lithiumophilic metal Zn was obtained.

[0219] The polyacrylonitrile film prepared by electrospinning with a thickness of 70 pm was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain a polyacrylonitrile film modified with the lyophilic polymer PEG-400.

[0220] The polyacrylonitrile film modified with the lyophilic polymer PEG-400 and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6x10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the polyacrylonitrile film modified with the lithiumophilic metal Zn and the lyophilic polymer PEG-400 was obtained.

[0221] The polyacrylonitrile film modified with the lithiumophilic metal Zn and the lyophilic polymer PEG-400 and the copper foil modified with the lithiumophilic metal Zn were stacked, and the lithiumophilic metal Zn on the polyacrylonitrile film was arranged opposite to the lithiumophilic metal Zn on the copper foil, and then cut into a rectangular sheet with a size of 42 mm x 52 mm as a negative electrode sheet.

[0222] Comparative Example 1

[0223] The preparation method of the battery monomer was the same as that of Example 1, except for the following differences.

[0224] Preparation of the negative electrode tab

[0225] The copper foil was cut into a rectangular sheet shape of 42 mm x 52 mm as the negative electrode tab.

[0226] Comparative Example 2

[0227] The preparation method of the battery monomer was the same as that of Example 1, except for the following differences.

[0228] Preparation of the negative electrode tab

[0229] The negative current collector copper foil and the metal zinc target were placed in a magnetron sputtering system, and the vacuum was pumped to 6 x 10 -4 Pa, argon was introduced, and then direct current sputtering was performed; the sputtering power was 60 W, and the sputtering pressure was 0.8 Pa; the surface density of Zn was adjusted to 0.2 mg / cm 2 by adjusting the sputtering time; the chamber was opened, and the copper foil modified with the lithiumophilic metal Zn was obtained, which was then cut into a rectangular sheet shape of 42 mm x 52 mm as the negative electrode tab.

[0230] Comparative Example 3

[0231] The preparation method of the battery monomer was the same as that of Example 1, except for the following differences.

[0232] Preparation of the negative electrode tab

[0233] The polyacrylonitrile film with a thickness of 100 μm prepared by electrospinning was completely immersed in a 5% PEG-400 dimethyl sulfoxide (DMSO) solution for 5 min, and then taken out and dried in an oven until the DMSO was completely volatilized, to obtain the polyacrylonitrile film modified with the lyophilic polymer PEG-400.

[0234] The polyacrylonitrile film modified with the lyophilic polymer PEG-400 and the negative current collector copper foil were superimposed, and then cut into a rectangular sheet shape of 42 mm x 52 mm as the negative electrode tab.

[0235] Performance test

[0236] The battery monomer was subjected to a cycle performance test at 25°C with 0.2C (28 mA) charging and 1C (140 mA) discharging. During the test, the in-situ expansion tester was used to apply a constant pressure of 0.5 MPa (109.2 kg) to the battery monomer.

[0237] Specifically, the battery monomer is charged at a rate of 0.2C to 4.3V, then charged at a constant voltage until the current attenuation is 0.15C; then discharged at a rate of 1C to a voltage of 2.8V to obtain the first circle discharge capacity; then the above steps are carried out according to the above steps. The capacity retention rate after 100 cycles = the discharge capacity after 100 cycles / the first circle discharge capacity x 100%.

[0238] The thickness of the battery monomer before the cycle test is denoted as H1, and the thickness of the battery monomer after 100 cycles of full discharge (0% SOC) is denoted as H2. The irreversible volume expansion after 100 cycles = H2-H1.

[0239] Table 1

[0240] From the above test results, it can be seen that the negative electrode sheet of the present disclosure can make the battery monomer have high first circle discharge capacity, high cycle capacity retention rate and low volume expansion.

[0241] From the test results of Examples 1 to 12 and Comparative Example 2, it can also be seen that the insulating framework of the present disclosure can improve the electrolyte wettability, and can alleviate polarization from the first cycle of the battery monomer cycle, improve the kinetic capacity of the battery monomer, and the insulating framework can also alleviate the irreversible volume expansion of the battery monomer after multiple cycles.

[0242] From the test results of Examples 1 to 12 and Comparative Example 3, it can also be seen that the insulating framework can improve the first circle discharge capacity of the battery monomer and reduce the irreversible volume expansion of the battery monomer after multiple cycles, but since the negative electrode sheet of Comparative Example 3 does not contain lithiumophilic material, it cannot slow down the side reaction and uniform lithium metal deposition morphology, thereby causing the capacity retention rate of the battery monomer after multiple cycles to decrease sharply.

[0243] From the test results of Examples 1 to 3, it can also be seen that further adjusting the thickness of the insulating framework can further improve the capacity retention rate of the battery monomer after multiple cycles and alleviate the irreversible volume expansion of the battery monomer after multiple cycles.

[0244] From the test results of Examples 1, Examples 6 to 8, it can also be seen that further adjusting the areal density of the lithiumophilic material can further improve the capacity retention rate of the battery monomer after multiple cycles and alleviate the irreversible volume expansion of the battery monomer after multiple cycles.

[0245] From the test results of Examples 1 and Example 11, it can also be seen that arranging the lyophilic polymer on the surface and voids of the insulating framework can improve the liquid binding effect of the negative electrode sheet, thereby being conducive to improving the kinetic capacity of the battery monomer and also being conducive to alleviating the irreversible volume expansion of the battery monomer after multiple cycles.

[0246] It can also be known from the test results of Example 1 and Example 12 that the lithium-philic material is located both on the copper foil and in the pores of the polyacrylonitrile film, and during the lithium metal deposition process, the polyacrylonitrile film and the copper foil can be connected into one, so as to improve the structural stability of the negative electrode, reduce the interface impedance of the battery monomer, so as to further improve the capacity retention rate of the battery monomer after multiple cycles and further alleviate the volume irreversible expansion of the battery monomer after multiple cycles.

[0247] It should be noted that the present disclosure is not limited to the above-described embodiments. The above-described embodiments are only examples, and embodiments having substantially the same configuration and playing the same effect as the technical idea within the scope of the technical solutions of the present disclosure are all included in the technical scope of the present disclosure. In addition, within the scope of the main idea of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other modes constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

A negative electrode sheet, wherein 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. The negative electrode sheet according to claim 1, wherein The lithiumophilic material comprises a lithiumophilic metal and / or a lithiumophilic alloy. The negative electrode sheet according to any one of claims 1-2, wherein The lithiumophilic material comprises one or more of the elements Zn, In, Al, Mg, Ag, Sn, Ga, Sb, Bi, Ge and alloys thereof. 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 . 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 . 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. 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. The negative electrode sheet according to claim 7, wherein The lyophilic group comprises one or more of a hydroxyl group, a carboxyl group, a carboxylate, and an amino group. The negative electrode sheet according to any one of claims 7-8, wherein The lyophilic polymer comprises one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, and derivatives thereof. The negative electrode tab according to 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 10-700μm; and / or The porosity of the insulating framework is greater than or equal to 80%. 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. The negative electrode tab according to 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 adipate, 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. The negative electrode tab according to 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. A battery monomer includes a positive electrode sheet, a separator film, and the negative electrode sheet of any one of claims 1-13, the separator film being located between the positive electrode sheet and the negative electrode sheet. A battery device includes a plurality of battery monomers of claim 14. An electric device includes the battery monomer of claim 14 or the battery device of claim 15.

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