Battery cell, battery device and electric device, and preparation method for negative electrode sheet

Abstract

Disclosed in the present disclosure are a battery cell, a battery device and an electric device, and a preparation method for a negative electrode sheet. The battery cell comprises a negative electrode sheet, wherein the negative electrode sheet comprises a foam metal substrate and metal nanowires located on prismatic wires on at least one surface of the foam metal substrate in the thickness direction thereof. The foam metal substrate comprises a metal element M. The metal nanowires comprise metal element M nanowires doped with an element A, wherein the element A comprises C. The battery cell has a high cycle stability and a long cycle life.

Description

Battery cell, battery device and power utilization device, and preparation method of negative electrode sheet

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411152376.4, filed on August 21, 2024, entitled “Battery cell, battery device and power utilization device, and preparation method of negative electrode sheet”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a battery cell, a battery device and a power utilization device, and a preparation method of a negative electrode sheet. BACKGROUND

[0004] Battery cells that achieve charge and discharge through deposition and stripping of metals such as lithium, sodium, etc. have high energy density, which is crucial for the realization of high endurance electric vehicles, unmanned aerial vehicles, electric aircraft, and other application scenarios. However, the cycle life of such battery cells is generally poor. SUMMARY

[0005] The present disclosure provides a battery cell, a battery device and a power utilization device, and a preparation method of a negative electrode sheet, which has high cycle stability and long cycle life.

[0006] In a first aspect, the present disclosure provides a battery cell, comprising a negative electrode sheet, the negative electrode sheet comprising a foamed metal substrate and metal nanowires on the prongs of at least one surface of the foamed metal substrate along its thickness direction; the foamed metal substrate comprises a metal element M; the metal nanowires comprise element A-doped metal element M nanowires, and the element A comprises C.

[0007] In the negative electrode sheet provided by the embodiments of the present disclosure, the abundant pore structure of the foamed metal substrate provides sufficient space to accommodate the deposited metal, thereby reducing the volume expansion of the negative electrode sheet and improving the stability of the negative electrode sheet.

[0008] In the negative electrode sheet provided by the embodiments of the present disclosure, the foamed metal substrate has doped metal nanowires on the prongs of at least one surface along its thickness direction, which further improves the specific surface area of the negative electrode sheet and also improves the wettability of the negative electrode sheet to the electrolyte; the doped metal nanowires also provide a large number of charge centers and electrochemical active sites, thereby uniformly distributing the charges on the surface of the foamed metal substrate and reducing the local current density; the doped metal nanowires also enable the negative electrode sheet to have a lower nucleation overpotential and more electrochemical active sites, thereby inhibiting dendrite growth and also improving the metal deposition morphology to achieve uniform and dense metal deposition.

[0009] Therefore, the battery cell with the negative electrode tab provided by the embodiment of the present disclosure has high cycle stability and long cycle life.

[0010] In some embodiments, the metal nanowires are also located on the ribs of the pore walls in the region from the surface to 0.25 times the thickness of the foam metal substrate. In this way, the cycle life of the battery cell can be further improved.

[0011] In some embodiments, the element A further includes N. The metal nanowires doped with C and N can further reduce the nucleation overpotential of the negative electrode, further improving the cycle life of the battery cell.

[0012] In some embodiments, the foam metal substrate includes a foam copper, and the metal nanowires include C and N doped copper nanowires.

[0013] In some embodiments, the total mass fraction of the elements C, N and M in the metal nanowires is 89%-100% based on the mass of the metal nanowires.

[0014] In some embodiments, the mass fraction of the element M in the metal nanowires is 70%-85% based on the mass of the metal nanowires.

[0015] In some embodiments, the length of the metal nanowires is 3-18 μm.

[0016] In some embodiments, the diameter of the metal nanowires is 0.14-0.70 μm.

[0017] The length and diameter of the metal nanowires in the above range are conducive to improving the cycle life of the battery cell.

[0018] In some embodiments, the aspect ratio of the metal nanowires is 8-70, which can be 10-40. The aspect ratio of the metal nanowires in the above range can further improve the cycle life of the battery cell.

[0019] In some embodiments, the thickness of the negative electrode tab is 80-180 μm.

[0020] In some embodiments, the porosity of the negative electrode tab is 72%-86%.

[0021] In some embodiments, the pore size distribution range of the negative electrode tab is 35-206 μm.

[0022] In some embodiments, the through-hole rate of the negative electrode tab is greater than or equal to 98%.

[0023] In some embodiments, the rib diameter distribution range of the negative electrode tab is 10-51 μm.

[0024] In some embodiments, the negative electrode tab further comprises an alkali metal on at least part of the metal nanowires, the alkali metal comprising one or both of Li and Na.

[0025] In a second aspect, the present disclosure provides a battery device comprising the battery cell of the first aspect of the present disclosure.

[0026] In a third aspect, the present disclosure provides a power consumption device comprising the battery cell of the first aspect of the present disclosure or the battery device of the second aspect of the present disclosure.

[0027] In a fourth aspect, the present disclosure provides a method for preparing a negative electrode tab, comprising the following steps: providing a foamed metal substrate, the foamed metal substrate comprising a metal element M; growing hydroxide nanowires of the metal element M on the struts of at least one surface of the foamed metal substrate along the thickness direction of the foamed metal substrate to obtain a foamed metal substrate with hydroxide nanowires of the metal element M; reacting the obtained foamed metal substrate with hydroxide nanowires of the metal element M with a solution containing an organic ligand to grow metal-organic framework compounds of the metal element M on the surface of the hydroxide nanowires of the metal element M, to obtain a foamed metal substrate with metal-organic framework compounds of the metal element M; and performing annealing treatment and reduction treatment on the obtained foamed metal substrate with metal-organic framework compounds of the metal element M to obtain a negative electrode tab, the negative electrode tab comprising a foamed metal substrate and metal nanowires on the struts of at least one surface of the foamed metal substrate along the thickness direction of the foamed metal substrate, the metal nanowires comprising element A-doped metal element M nanowires, the element A comprising C.

[0028] In some embodiments, the organic ligand has any one of or a combination of two or more of a N-heterocyclic structure, an amine group structure, a carboxyl group structure, a phenol group structure. Optionally, the organic ligand includes one or more of imidazole, 2-methylimidazole, N-methylimidazole, 1-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-propylimidazole, benzimidazole, 2-methylbenzimidazole, 2-aminobenzimidazole, 3,3',5,5'-tetra(1H-imidazol-1-yl)-1,1'-biphenyl, 1H-imidazole-4-carboxylic acid, tris(4-(1-imidazolyl)phenyl)amine, 2-(diphenylphosphino)-1-methyl-1H-imidazole, 1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-bisphosphonic acid, phenyl bis-1H-imidazol-1-ylphosphonate, 2-(dicyclohexylphosphino)-1-(2,4,6-trimethyl-phenyl)-1H-imidazole, 3-(diphenylphosphino)-2-methylimidazo[1,2-A]pyridine, pyrazole, 3-methylpyrazole, 5-methylpyrazole, 1,3-dimethylpyrazole, 3,5-dimethylpyrazole, 1,5-dimethylpyrazole, phenylpyrazole, 1,4-di(1H-pyrazol-4-yl)benzene, pyridine, 2-methylpyridine, 3-ethylpyridine, 3-propylpyridine, 3-butylpyridine, 3-isobutylpyridine, 3-(tert-butyl)pyridine, 1,3-dimethylpyridine, 2,6-dimethylpyridine, 2-aminopyridine, 4,4-bipyridine, 2,2'-bipyridine, 4-phenylterpyridine, 4-methylphenylterpyridine, 4-carboxyphenylterpyridine, 4-nitrophenylterpyridine, 3,5-bis(1-imidazolyl)pyridine, 3,5-bis(1-benzimidazolyl)pyridine, 5-(4-pyridyl)-1,3-oxazole, thiazole, thiazolidine-2,4-dicarboxylic acid, oxazole, pyrimidine, 1,3,5-triazine, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 1,2,4,5-tetrazine, pyridazine, pyrazine, p-phenylenediamine, p-xylylenediamine, aniline, terephthalic acid, 2-amino terephthalic acid, 2,5-dihydroxy terephthalic acid, terephthalic acid, isophthalic acid, 1,3,5-benzenetricarboxylic acid, fumaric acid, triphenylene-2,6,10-tricarboxylic acid, 1,3,5-tris(4'-carboxy[1,1'-biphenyl]-4-yl)benzene, benzimidazole-4-carboxylic acid, benzoxazole-5-carboxylic acid, p-phenylpyridine-2,5-dicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 3,6-dicarboxypyridazine, 2,5-pyrimidinedicarboxylic acid, 1,2,4-triazine-3,6-dicarboxylic acid, 1,2,4,5-tetrazine-3,6-dicarboxylic acid, hydroquinone, 2,5-dihydroxyphenol.

[0029] In some embodiments, the step of growing the hydroxide nanowires of the metal element M on the ribbons of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate itself comprises the following steps: at least partially immersing the foam metal substrate in an aqueous solution containing a strong base and a persulfate salt for reaction, and drying after taking out, to obtain a foam metal substrate with the hydroxide nanowires of the metal element M, wherein the strong base comprises one or both of sodium hydroxide and potassium hydroxide, and the persulfate salt comprises one or more of ammonium persulfate, sodium persulfate, and potassium persulfate.

[0030] In some embodiments, the concentration of the strong base is 1.5 mol / L-3.5 mol / L.

[0031] In some embodiments, the concentration of the persulfate salt is 0.05 mol / L-0.2 mol / L.

[0032] In some embodiments, the time for at least partially immersing the foam metal substrate in the aqueous solution containing the strong base and the persulfate salt for reaction is 5 min-30 min.

[0033] In some embodiments, the atmosphere of the annealing treatment is a protective gas atmosphere.

[0034] In some embodiments, the temperature of the annealing treatment is 200°C-400°C.

[0035] In some embodiments, the time of the annealing treatment is 0.5 h-3.5 h. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and other drawings can also be obtained according to the drawings without paying creative labor for those skilled in the art.

[0037] FIG. 1 shows a schematic diagram of a battery cell according to some embodiments of the present disclosure.

[0038] FIG. 2 shows a schematic diagram of the preparation process of a negative electrode sheet according to some embodiments of the present disclosure. FIG. 2a shows a schematic diagram of a foam metal substrate, FIG. 2b shows a schematic diagram of a foam metal substrate with hydroxide nanowires of a metal element M, FIG. 2c shows a schematic diagram of a foam metal substrate with a metal organic framework compound of a metal element M, and FIG. 2d shows a schematic diagram of a foam metal substrate with nanowires of a metal element M doped with an element A.

[0039] FIG. 3 shows scanning electron microscope (SEM) images of the foamed copper of Example 1 at different stages of preparation. FIG. 3a and FIG. 3b show scanning electron microscope (SEM) images of the untreated foamed copper of Example 1, FIG. 3c and FIG. 3d show scanning electron microscope (SEM) images of the foamed copper of Example 1 prepared with Cu(OH)2nanowire arrays, FIG. 3e and FIG. 3f show scanning electron microscope (SEM) images of the foamed copper of Example 1 prepared with Cu-based metal organic frameworks, and FIG. 3g and FIG. 3h show scanning electron microscope (SEM) images of the foamed copper of Example 1 provided with C and N doped copper nanowires. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the battery cell, the battery device, and the power consuming device, the method of manufacturing the negative electrode sheet of the present disclosure are specifically disclosed in detail with appropriate reference to the accompanying 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. Furthermore, the accompanying drawings and the following description are provided so that those skilled in the art can fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0041] The ranges disclosed by the present disclosure are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., 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 particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if a minimum range value of 1 and 2 is listed, and if a maximum range value of 3, 4, and 5 is listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present disclosure, unless otherwise stated, a numerical range "a-b" represents a shorthand manner of describing any integer combination of the range between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and the like.

[0042] If not specifically stated, all embodiments of the present disclosure and optional embodiments 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.

[0043] 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, unless otherwise specified.

[0044] If not specifically stated, 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.

[0045] If not specifically stated, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, and are not used to describe a specific order or primary and secondary relationship.

[0046] In the present disclosure, the terms "a plurality of" and "a plurality of" refer to two or more.

[0047] In the description of the embodiments of the present disclosure, if not specifically stated, 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 "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0048] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25°C.

[0049] 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, parallel or mixed connection through a busbar component.

[0050] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells.

[0051] As an example, the battery cell assembly can be a battery module. The battery module is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells by a cable tie.

[0052] In some embodiments, the battery device can be a battery pack. The battery pack includes a case and one or more battery cell assemblies. The battery cell assemblies are accommodated in the case.

[0053] As an example, the battery cell assembly can be a battery module. The battery cell assembly can be accommodated in the case by fixing the battery module in the case.

[0054] As an example, the battery cell assembly can also be accommodated in the case by directly fixing a plurality of battery cells in the case.

[0055] 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 enclosed space is formed inside the case to accommodate the battery cell assembly. Here, enclosed means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0056] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame so that an enclosed space is formed inside the case to accommodate the battery cell assembly.

[0057] In some embodiments, the case can be part of the chassis structure of a vehicle. For example, part of the case can be at least part of the floor of the vehicle, or part of the case can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0058] 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 aircraft, energy storage systems, etc. The battery cells or battery devices are used to store or provide electric energy.

[0059] The battery cell is the smallest unit that constitutes the battery device, and can independently realize the functions of charging and discharging. 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 in the shape of a cuboid as an example.

[0060] Battery cells that achieve charge and discharge through deposition and stripping of lithium, sodium and the like have poor cycle life. This is because there is no carbon-based negative electrode active material for lithium, sodium and the like to be stripped and inserted, and lithium, sodium and the like will be unevenly deposited and stripped and will have unlimited volume expansion during the cycle, which will cause the solid electrolyte interface (SEI) film of the negative electrode to repeatedly crack and grow, lithium, sodium and the like will continuously react with the electrolyte, and then the cycle life of the battery cell will be poor. In addition, the negative electrode is also prone to grow dendrites during the cycle, and the continuous growth of the dendrites will pierce the separator, causing internal short circuit of the battery cell and affecting the reliability of the battery cell.

[0061] Based on this, the present disclosure provides a battery cell with long cycle life from the structure of the negative electrode tab.

[0062] The battery cell provided by the embodiments of the present disclosure can include an alkali metal battery cell, a negative electrode-free alkali metal battery cell, an alkali metal-sulfur battery cell, such as a lithium metal battery cell, a negative electrode-free lithium metal battery cell, a lithium-sulfur battery cell, a sodium metal battery cell, a negative electrode-free sodium metal battery cell, a sodium-sulfur battery cell, and the like.

[0063] The negative electrode-free alkali 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, for example, a negative electrode active material layer is not formed by coating or depositing a carbon-based active material layer on the negative electrode during the manufacturing process of the battery cell. During the first charge, ions obtain electrons on the negative electrode side and deposit to form an alkali metal phase on the negative electrode surface, and during discharge, the alkali metal can be converted into alkali metal ions to return to the positive electrode, achieving cycle charging and discharging. Compared with other battery cells, the negative electrode-free alkali metal battery cell has higher energy density due to the absence of the negative electrode active material layer. The alkali metal-sulfur battery cell is a battery system that uses sulfur-based materials including sulfur-sulfur (S-S) bonds as positive electrode active materials, and achieves mutual conversion between chemical energy and electrical energy through the two-electron electrochemical reaction between sulfur and alkali metal.

[0064] The battery cell provided by the embodiments of the present disclosure includes a negative electrode tab.

[0065] The negative electrode tab provided by the embodiments of the present disclosure includes a foam metal substrate and metal nanowires on the prongs of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate, the foam metal substrate includes a metal element M, and the metal nanowires include element A-doped metal element M nanowires, and the element A includes C.

[0066] The foam metal substrate has abundant pore structure and high specific surface area, and can accommodate deposited metal, but the structure of the deposited metal is usually loose and porous, and the SEI film of the negative electrode is prone to repeated cracking and growth during the cycle, thereby causing poor cycle performance of the battery cell.

[0067] The negative electrode tab provided by the embodiments of the present disclosure has a foam metal substrate with a rich pore structure, which provides sufficient space to accommodate deposited metal, thereby reducing the volume expansion of the negative electrode tab and improving the stability of the negative electrode tab.

[0068] The negative electrode tab provided by the embodiments of the present disclosure has doped metal nanowires on the ribs of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate, which further improves the specific surface area of the negative electrode tab and improves the wettability of the negative electrode tab to the electrolyte; the doped metal nanowires also provide a large number of charge centers and electrochemically active sites, thereby uniformly distributing the charges on the surface of the foam metal substrate and reducing the local current density; the doped metal nanowires also enable the negative electrode tab to have a lower nucleation overpotential and more electrochemically active sites, thereby inhibiting dendrite growth and improving the metal deposition morphology to achieve uniform and dense metal deposition.

[0069] Therefore, the battery cell using the negative electrode tab provided by the embodiments of the present disclosure has high cycle stability and long cycle life.

[0070] In some embodiments, the metal nanowires can also be located on the ribs of the pore walls within a region from the surface to 0.25 times the thickness of the foam metal substrate.

[0071] That is, the ribs of the surface of the foam metal substrate and the ribs of the pore walls within a region from the surface to 0.25 times the thickness are both provided with metal nanowires. This can further improve the cycle life of the battery cell.

[0072] Optionally, the metal nanowires can also be located on the ribs of the pore walls within a region from the surface to 0.15 times the thickness of the foam metal substrate. More optionally, the metal nanowires can also be located on the ribs of the pore walls within a region from the surface to 0.1 times the thickness of the foam metal substrate.

[0073] In some embodiments, the element A can also include N, that is, the element A can simultaneously include C and N.

[0074] The metal nanowires doped with C and N can further reduce the nucleation overpotential of the negative electrode and further improve the cycle life of the battery cell.

[0075] In some embodiments, the foam metal substrate includes foam copper, and the metal nanowires include C and N doped copper nanowires.

[0076] In some embodiments, the total mass fraction of the elements C, N, and M in the metal nanowires can be 89%-100% based on the mass of the metal nanowires.

[0077] Optionally, the total mass fraction of the element C, the element N, and the element M in the metal nanowire can be 91-100%, 93-100%, 95-100%, 97-100%, 99-100%, 89-99%, 91-99%, 93-99%, 95-99%, 97-99%, based on the mass of the metal nanowire.

[0078] In some embodiments, the total mass fraction of the element C, the element N, and the element M in the metal nanowire can be 100%, based on the mass of the metal nanowire.

[0079] In some embodiments, the metal nanowire can further include the element O.

[0080] Optionally, the mass fraction of the element O in the metal nanowire can be less than or equal to 11%, based on the mass of the metal nanowire.

[0081] More optionally, the mass fraction of the element O in the metal nanowire can be less than or equal to 9%, less than or equal to 8%, less than or equal to 7%, less than or equal to 6%, less than or equal to 5%, less than or equal to 4%, less than or equal to 3%, less than or equal to 2%, less than or equal to 1%.

[0082] In some embodiments, the mass fraction of the element M in the metal nanowire can be 70-85%, for example, can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, or a range consisting of any of the aforementioned values, based on the mass of the metal nanowire.

[0083] In some embodiments, the length of the metal nanowire can be 3-18 μm, for example, can be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, or a range consisting of any of the aforementioned values.

[0084] Optionally, the length of the metal nanowire can be 3-16 μm, 3-14 μm, 3-12 μm, 3-10 μm, 4-16 μm, 4-14 μm, 4-12 μm, 4-10 μm, 5-16 μm, 5-14 μm, 5-12 μm, 5-10 μm.

[0085] In some embodiments, the metal nanowire can have a diameter of 0.14 μm to 0.70 μm, for example, 0.14 μm, 0.16 μm, 0.18 μm, 0.20 μm, 0.22 μm, 0.24 μm, 0.26 μm, 0.28 μm, 0.30 μm, 0.32 μm, 0.34 μm, 0.36 μm, 0.38 μm, 0.40 μm, 0.42 μm, 0.44 μm, 0.46 μm, 0.48 μm, 0.50 μm, 0.52 μm, 0.54 μm, 0.56 μm, 0.58 μm, 0.60 μm, 0.62 μm, 0.64 μm, 0.66 μm, 0.68 μm, 0.70 μm, or a range of any of the above values.

[0086] The length and diameter of the metal nanowire within the above ranges can be beneficial for improving the cycle life of the battery cell.

[0087] In some embodiments, the aspect ratio of the metal nanowire can be 8 to 70, for example, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, or a range of any of the above values.

[0088] Optionally, the aspect ratio of the metal nanowire can be 10 to 60, 10 to 50, 10 to 40, 14 to 60, 14 to 50, 14 to 40.

[0089] The aspect ratio of the metal nanowire within the above ranges can further improve the cycle life of the battery cell.

[0090] In some embodiments, the thickness of the negative electrode tab can be 80 μm to 180 μm, for example, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, or a range of any of the above values. Optionally, the thickness of the negative electrode tab can be 80 μm to 150 μm.

[0091] In some embodiments, the porosity of the negative electrode tab can be 72% to 86%, for example, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, or a range of any of the above values.

[0092] In some embodiments, the pore size distribution of the negative electrode tab can be 35 μm to 206 μm.

[0093] In some embodiments, the negative electrode tab can have a through hole rate of 98% or more.

[0094] In some embodiments, the negative electrode tab can have a rib diameter distribution range of 10 μm-51 μm.

[0095] In some embodiments, the negative electrode tab can further include an alkali metal on at least part of the metal nanowires.

[0096] Optionally, the alkali metal can include one or both of Li and Na.

[0097] In some embodiments, the negative electrode tab can further include an alkali metal on the metal nanowires and inside the pores of the foam metal substrate. That is, the alkali metal is on both the metal nanowires and inside the pores of the foam metal substrate.

[0098] The present disclosure also provides a method for preparing a negative electrode tab.

[0099] The method for preparing a negative electrode tab includes the following steps: providing a foam metal substrate, the foam metal substrate including a metal element M; growing hydroxide nanowires of the metal element M on ribs on at least one surface of the foam metal substrate along a thickness direction of the foam metal substrate, to obtain a foam metal substrate with the hydroxide nanowires of the metal element M; reacting the obtained foam metal substrate with the hydroxide nanowires of the metal element M with a solution containing an organic ligand, to grow a metal organic framework (MOF) of the metal element M on surfaces of the hydroxide nanowires of the metal element M, to obtain a foam metal substrate with the MOF of the metal element M; and performing annealing treatment and reduction treatment on the obtained foam metal substrate with the MOF of the metal element M, to obtain a negative electrode tab. The negative electrode tab includes a foam metal substrate and metal nanowires on ribs on at least one surface of the foam metal substrate along a thickness direction of the foam metal substrate, the metal nanowires including element A-doped metal element M nanowires, the element A including C.

[0100] FIG. 2 shows a schematic diagram of a preparation process of a negative electrode tab according to some embodiments of the present disclosure. As shown in FIG. 2, taking a foamed copper as an example, an exemplary preparation method of the negative electrode tab includes the following steps: providing a foamed copper (FIG. 2a); growing copper hydroxide nanowires on the ridges of at least one surface of the foamed copper along the thickness direction of the foamed copper to obtain a foamed copper with copper hydroxide nanowires (FIG. 2b); reacting the obtained foamed copper with copper hydroxide nanowires with a solution containing an organic ligand to grow copper-based metal organic framework compounds on the surface of the copper hydroxide nanowires to obtain a foamed copper with copper-based metal organic framework compounds (FIG. 2c); and performing annealing treatment and reduction treatment on the obtained foamed copper with copper-based metal organic framework compounds to obtain a foamed copper with copper nanowires doped with element A (FIG. 2d).

[0101] In some embodiments, the solvent in the solution containing the organic ligand can include, but is not limited to, one or more of water, alcohol, amide.

[0102] In some embodiments, the organic ligand can include any one of or a combination of two or more of N-heterocyclic structure, amine group structure, carboxyl group structure, and phenolic group structure.

[0103] Optionally, the organic ligand can include one or more of imidazole ligand, pyrazole ligand, pyridine ligand, thiazole ligand, oxazole ligand, pyrimidine ligand, triazine ligand, tetrazine ligand, pyridazine ligand, pyrazine ligand, aromatic amine ligand, carboxyl ligand, and phenolic ligand.

[0104] More optionally, the organic ligand can include one or more of imidazole, 2-methylimidazole, N-methylimidazole, 1-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-propylimidazole, benzimidazole, 2-methylbenzimidazole, 2-aminobenzimidazole, 3,3',5,5'-tetra(lH-imidazol-l-yl)-l,l'-biphenyl, lH-imidazole-4-carboxylic acid, tris(4-(l-imidazolyl)phenyl)amine, 2-(diphenylphosphino)-l-methyl-lH-imidazole, l-hydroxy-2-(lH-imidazol-l-yl)ethane-l,l-bisphosphonic acid, phenyl di-lH-imidazol-l-ylphosphonate, 2-(dicyclohexylphosphino)-l-(2,4,6-trimethyl-phenyl)-lH-imidazole, 3-(diphenylphosphino)-2-methylimidazo[l,2-A]pyridine, pyrazole, 3-methylpyrazole, 5-methylpyrazole, 1,3-dimethylpyrazole, 3,5-dimethylpyrazole, 1,5-dimethylpyrazole, phenylpyrazole, 1,4-di(lH-pyrazol-4-yl)benzene, pyridine, 2-methylpyridine, 3-ethylpyridine, 3-propylpyridine, 3-butylpyridine, 3-isobutylpyridine, 3-(tert-butyl)pyridine, 1,3-dimethylpyridine, 2,6-dimethylpyridine, 2-aminopyridine, 4,4-bipyridine, 2,2'-bipyridine, 4-phenylterpyridine, 4-methylphenylterpyridine, 4-carboxyphenylterpyridine, 4-nitrophenylterpyridine, 3,5-bis(l-imidazolyl)pyridine, 3,5-bis(l-benzimidazolyl)pyridine, 5-(4-pyridyl)-l,3-oxazole, thiazole, thiazolidine-2,4-dicarboxylic acid, oxazole, pyrimidine, 1,3,5-triazine, 2,4,6-tris(4-carboxyphenyl)-l,3,5-triazine, 1,2,4,5-tetrazine, pyridazine, pyrazine, p-phenylenediamine, p-tolylenediamine, aniline, terephthalic acid, 2-amino terephthalic acid, 2,5-dihydroxy terephthalic acid, terephthalic acid, isophthalic acid, 1,3,5-benzenetricarboxylic acid, fumaric acid, triphenylene-2,6,10-tricarboxylic acid, 1,3,5-tris(4'-carboxy[l,l'-biphenyl]-4-yl)benzene, benzimidazole-4-carboxylic acid, benzoxazole-5-carboxylic acid, pteridine-2,5-dicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 3,6-dicarboxypyridazine, 2,5-pyrimidinedicarboxylic acid, 1,2,4-triazine-3,6-dicarboxylic acid, 1,2,4,5-tetrazine-3,6-dicarboxylic acid, hydroquinone, 2,5-dihydroxyphenol.

[0105] In some embodiments, before growing the hydroxide nanowires of the metal element M on the prongs of the at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate, the method of preparing the negative electrode sheet can further include a step of cleaning the foam metal substrate. Optionally, the cleaning method can include plasma cleaning, water cleaning, organic solvent cleaning, etc.

[0106] In some embodiments, the step of growing the hydroxide nanowires of the metal element M on the struts of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate includes the steps of: at least partially immersing the foam metal substrate in an aqueous solution containing a strong base and a persulfate salt for reaction, and drying after taking out, to obtain a foam metal substrate with the hydroxide nanowires of the metal element M. The strong base includes one or both of sodium hydroxide and potassium hydroxide, and the persulfate salt includes one or more of ammonium persulfate, sodium persulfate, and potassium persulfate.

[0107] At least partially immersing the foam metal substrate in the aqueous solution containing the strong base and the persulfate salt for reaction can grow the hydroxide nanowires of the metal element M on the struts of the surface of the foam metal substrate and at least part of the struts of the pore walls inside the foam metal substrate. This can further improve the cycle life of the battery cell.

[0108] Optionally, the concentration of the strong base can be 1.5 mol / L-3.5 mol / L, for example, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.7 mol / L, 2.8 mol / L, 2.9 mol / L, 3 mol / L, 3.1 mol / L, 3.2 mol / L, 3.3 mol / L, 3.4 mol / L, 3.5 mol / L, or a range formed by any of the above values.

[0109] More optionally, the concentration of the strong base can be 2 mol / L-3 mol / L, 2.1 mol / L-3 mol / L, 2.2 mol / L-3 mol / L, 2.3 mol / L-3 mol / L, 2.4 mol / L-3 mol / L, 2.5 mol / L-3 mol / L, 2.6 mol / L-3 mol / L, 2 mol / L-2.9 mol / L, 2.1 mol / L-2.9 mol / L, 2.2 mol / L-2.9 mol / L, 2.2 mol / L-2.9 mol / L, 2.4 mol / L-2.9 mol / L, 2.5 mol / L-2.9 mol / L, 2.6 mol / L-2.9 mol / L.

[0110] Optionally, the concentration of the persulfate salt can be 0.05 mol / L - 0.2 mol / L, for example, can be 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.11 mol / L, 0.12 mol / L, 0.13 mol / L, 0.14 mol / L, 0.15 mol / L, 0.16 mol / L, 0.17 mol / L, 0.18 mol / L, 0.19 mol / L, 0.2 mol / L, or a range consisting of any of the foregoing values.

[0111] More optionally, the concentration of the persulfate salt can be 0.08 mol / L - 0.16 mol / L, 0.08 mol / L - 0.14 mol / L, 0.08 mol / L - 0.12 mol / L.

[0112] Optionally, the time for the reaction of at least partially immersing the foamed metal substrate in the aqueous solution comprising the strong base and the persulfate salt can be 5 min - 30 min, for example, can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, or a range consisting of any of the foregoing values.

[0113] More optionally, the time for the reaction of at least partially immersing the foamed metal substrate in the aqueous solution comprising the strong base and the persulfate salt can be 6 min - 20 min, 6 min - 18 min, 6 min - 16 min, 6 min - 14 min, 6 min - 12 min, 8 min - 20 min, 8 min - 18 min, 8 min - 16 min, 8 min - 14 min, 8 min - 12 min.

[0114] In some embodiments, the atmosphere of the annealing process can be a protective gas atmosphere. Optionally, the protective gas can include, but is not limited to, one or more of nitrogen, argon, helium.

[0115] In some embodiments, the temperature of the annealing process can be 200 °C - 400 °C, for example, can be 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, 250 °C, 260 °C, 270 °C, 280 °C, 290 °C, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C, 390 °C, 400 °C, or a range consisting of any of the foregoing values.

[0116] Optionally, the temperature of the annealing process can be 240 °C - 360 °C.

[0117] In some embodiments, the annealing treatment can be performed for 0.5h-3.5h, for example, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h, 3h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, or a range defined by any two of the above values.

[0118] Optionally, the annealing treatment can be performed for 1h-3h.

[0119] In some embodiments, the step of reducing the foam metal substrate after the annealing treatment comprises the step of electrochemically reducing the foam metal substrate obtained after the annealing treatment in an electrolyte solution by using a three-electrode standard system to obtain a negative electrode sheet.

[0120] Optionally, the electrolyte solution can comprise one or more of potassium bicarbonate, potassium bisulfate, sodium bicarbonate, sodium bisulfate.

[0121] Optionally, the electrolyte solution can be an aqueous potassium bicarbonate solution, and the concentration of the aqueous potassium bicarbonate solution can be 0.05mol / L-1mol / L. More optionally, the concentration of the aqueous potassium bicarbonate solution can be 0.1mol / L.

[0122] During the electrochemical reduction, the potential can be swept from -0.9V to -1.6V, and the scan rate can be 0.02V / s, and the reduction can be maintained at -1.6V for 10min-60min.

[0123] Optionally, the counter electrode can be a platinum sheet, a platinum wire, or a platinum mesh.

[0124] Optionally, the reference electrode can be a mercury / mercury oxide electrode, a silver / silver chloride electrode, or a saturated calomel electrode.

[0125] In some embodiments, the method for preparing the negative electrode sheet can further comprise the step of disposing an alkali metal on the metal nanowires and in the pores of the foam metal substrate. Optionally, the method for disposing the alkali metal can be an electrochemical deposition method.

[0126] The battery cell provided by the embodiments of the present disclosure further comprises a positive electrode sheet, a separator, and an electrolyte, and the separator is located between the positive electrode sheet and the negative electrode sheet.

[0127] [Positive electrode sheet]

[0128] In some embodiments, the positive electrode tab includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer including a positive electrode active material. For example, the positive electrode current collector has two surfaces opposite in the thickness direction of the positive electrode current collector, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0129] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, an aluminum 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 an example, the metal material can include, but is not limited to, one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. As an example, 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.

[0130] In some embodiments, the positive electrode active material includes a material capable of deintercalating and intercalating lithium, and optionally, the positive electrode active material can include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and modified compounds of each thereof. Examples of the lithium transition metal oxides can 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 modified compounds of each thereof. 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, and modified compounds of each thereof. The modified compounds of each of the above-mentioned positive electrode active materials can be a doping modification and / or a surface coating modification of the positive electrode active material.

[0131] In some embodiments, in order to further improve the energy density of the battery cell, the positive electrode active material can include one or more of lithium transition metal oxides of the general formula 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 includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes one or more of N, F, S, and Cl.

[0132] As an example, the positive active material can include, but is not limited to, one or more of LiCoO2, LiNiO2, LiMnO2, LiMn2O4, 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 0.96 Co 0.02 Mn 0.02 O2(abbreviated as Ni96), LiNi 0.80 Co 0.15 Al 0.05 O2, LiFePO4, LiMnPO4, and respective modified compounds thereof.

[0133] In some embodiments, the positive active material can include a material capable of deintercalating and intercalating sodium. For example, the positive active material can include, but is not limited to, one or more of a layered transition metal oxide (including, but not limited to, P2-type, O3-type, etc.), a polyanion material (such as a phosphate, a fluorophosphate, a pyrophosphate, a sulfate, etc.), a Prussian-type material. As an example, the positive active material can include, but is not limited to, one or more of NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, Na 0.67 MO2(M includes at least two of Fe, Co, Cr, Mn, Ni, V, Ti, Mo), NaMO2(M includes at least two of Fe, Co, Ni, V, Ti, Mo), NaFePO4, NaMnPO4, NaCoPO4, Na4Fe3(PO4)2O7, Na3V2(PO4)2F3, Na3V2(PO4)3, Prussian blue, Prussian white, and respective modified compounds thereof.

[0134] In some embodiments, the positive active material can include one or more of elemental sulfur, a sulfur-containing compound. Optionally, the sulfur-containing compound can include Li2S n , an organic sulfur compound, a carbon-sulfur polymer (C2S x )m one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0135] In some embodiments, the positive electrode film layer can further include a binder. As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0136] In some embodiments, the positive electrode film layer can further include a conductive agent. As an example, the conductive agent can include at least one of super P, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0137] In some embodiments, the positive electrode tab can be prepared by dispersing the above-mentioned components for preparing the positive electrode tab, such as the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry, coating the positive electrode slurry on a positive electrode current collector, and then drying, cold-pressing, or the like to obtain the positive electrode tab.

[0138] [Separator]

[0139] The separator is disposed between the positive electrode tab and the negative electrode tab and mainly functions to prevent internal short circuit. The type of the separator is not particularly limited in the present disclosure, and any publicly known porous structure film having good chemical stability and mechanical stability can be used. 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.

[0140] [Electrolyte]

[0141] In some embodiments, the electrolyte uses an electrolyte solution including an electrolyte salt and an organic solvent.

[0142] In some embodiments, the electrolyte solution includes an anion, which can include a bisfluorosulfonylimide anion (FSI - ), a bistrifluoromethylsulfonylimide anion (TFSI - ), a bisoxalateborate anion (BOB - ), a difluorooxalateborate anion (DFOB - ), a difluorodioxalatephosphate anion (DFOP - ), a tetrafluorooxalatephosphate anion (TFOP -one or more of a tetrafluoroborate anion (BF4 - ), a hexafluorophosphate anion (PF6 - ), a tetrafluoroborate anion (BF4 - ), a hexafluoroarsenate anion (AsF6 - ), a triflate anion (CF3SO3 - ), or a combination thereof.

[0143] In some embodiments, the electrolyte includes cations, which can include one or both of lithium ions and sodium ions.

[0144] In some embodiments, the electrolyte salt can have a concentration of 0.3 mol / L or more, optionally 0.7 mol / L or more, and further can have a concentration of 4 mol / L or less, optionally 2.5 mol / L or less, 1.7 mol / L or less. The electrolyte salt can have a concentration within the above ranges to provide the electrolyte with a suitable ionic conductivity.

[0145] The organic solvent can include, but is not limited to, one or more of esters, ethers, sulfones, nitriles, etc. The esters can include, but are not limited to, one or more of carbonates, phosphates, carboxylates, sulfates, sulfonates, etc. The carbonates can include cyclic carbonates and / or chain carbonates, optionally, the carbonates can include both cyclic carbonates and chain carbonates. The chain carbonates can include polar chain carbonates with low viscosity, aliphatic branched chain carbonates, etc.

[0146] As an example, the organic solvent can include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), 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), dimethyl ether tetraglyme (TEGDME), ethylene glycol dimethyl ether (DME), 1,3-dioxolane (DOL), trimethyl phosphate, 3-methoxypropionitrile, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), H(CF2)2OCH3, C4F9OCH3, H(CF2)2OCH2CH3, H(CF2)2OCH2CF3, CF3CHFCF2OCH3, CF3CHFCF2OCH2CH3, 2-trifluoromethylhexafluoropropyl methyl ether, 2-trifluoromethylhexafluoropropyl ethyl ether, 2-trifluoromethylhexafluoropropyl propyl ether, 3-trifluoromethyloctafluorobutyl methyl ether, 3-trifluoromethyloctafluorobutyl ethyl ether, 3-trifluoromethyloctafluorobutyl propyl ether, 4-trifluoromethyldodecafluoropentyl methyl ether, 4-trifluoromethyldodecafluoropentyl ethyl ether, 4-trifluoromethyldodecafluoropentyl propyl ether, 5-trifluoromethyldodecafluorohexyl methyl ether, 5-trifluoromethyldodecafluorohexyl ethyl ether, 5-trifluoromethyldodecafluorohexyl propyl ether, 6-trifluoromethyldodecafluoroheptyl methyl ether, 6-trifluoromethyldodecafluoroheptyl ethyl ether, 6-trifluoromethyldodecafluoroheptyl propyl ether, 7-trifluoromethyldodecafluorooctyl methyl ether, 7-trifluoromethyldodecafluorooctyl ethyl ether, 7-trifluoromethyldodecafluorooctyl propyl ether.

[0147] In some embodiments, the electrolyte can further include an additive. 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 capable of improving overcharge performance, an additive capable of improving high-temperature performance, an additive capable of improving low-temperature power performance, etc.

[0148] 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 to obtain an electrode assembly, the electrode assembly can be placed in an outer package, and after drying, the electrolyte described above can be injected, and the battery cell can be obtained after processes such as packaging, standing, etc.

[0149] Embodiments

[0150] The present disclosure is more particularly described in the following examples that are intended to be illustrative only since modifications and variations from the details provided can be apparent to those skilled in the art. Unless otherwise noted, all parts, percentages and ratios reported herein are on a weight basis, and all reagents used in the examples were commercially available or were synthesized using standard methods known in the art, and used without further purification, and the equipment used in the examples is commercially available.

[0151] Example 1

[0152] The foamed metal substrate used was foamed copper, with a thickness of 130 μm, an areal density of 212 g / m2, a porosity of 78.4%, a through porosity of 98%, a pore size distribution range of 72 μm-206 μm, and a wire diameter distribution range of 34 μm-51 μm. 2

[0153] An aqueous sodium hydroxide solution and an aqueous ammonium persulfate solution were mixed and stirred to obtain a reaction solution. The concentration of sodium hydroxide in the reaction solution was 2.7 mol / L, and the concentration of ammonium persulfate was 0.1 mol / L.

[0154] The foamed copper was cleaned on both sides using a plasma cleaning machine for 6 min, and then one side of the foamed copper was inverted in the prepared reaction solution for 10 min to grow Cu(OH)2nanowire arrays in situ on the wires on the surface of the foamed copper. After the reaction, the foamed copper was removed, washed three times with deionized water and anhydrous ethanol, and dried. The dried foamed copper was placed in a 2-methylimidazole saturated aqueous solution at 25°C for 30 s to generate Cu-based metal organic framework compounds CuMOF in situ on the Cu(OH)2nanowires. After the reaction, the foamed copper was removed, washed with deionized water, and dried. The dried foamed copper was placed in a tube furnace and annealed at 300°C under an argon atmosphere for 2 h. Then, using a three-electrode standard system, the foamed copper was electrochemically reduced in a 0.1 mol / L KHCO3 aqueous solution to obtain foamed copper with C and N-doped copper nanowires. During the electrochemical reduction, the potential was scanned from -0.9 V to -1.6 V at a scan rate of 0.02 V / s, and maintained at -1.6 V for 20 min. The counter electrode was a platinum mesh, and the reference electrode was a silver / silver chloride electrode.

[0155] ​Figure 3 shows scanning electron microscope (SEM) images of the foamed copper of Example 1 at different stages of preparation. Figure 3a and 3b show scanning electron microscope (SEM) images of the untreated foamed copper of Example 1, Figure 3c and 3d show scanning electron microscope (SEM) images of the foamed copper of Example 1 prepared with Cu(OH)2nanowire arrays, Figure 3e and 3f show scanning electron microscope (SEM) images of the foamed copper of Example 1 prepared with Cu-based metal organic framework, and Figure 3g and 3h show scanning electron microscope (SEM) images of the foamed copper of Example 1 provided with C and N doped copper nanowires.

[0156] Performance test of button cell (half cell)

[0157] The button cell was assembled in the order of negative shell, spring sheet, gasket, lithium sheet, separator membrane, and the above prepared foamed copper with C and N doped copper nanowires. The amount of electrolyte was 80 μL, the solvent was ethylene glycol dimethyl ether (DME), the lithium salt was lithium bisfluorosulfonylimide (LiFSI), and the concentration was 1 mol / L. The diameter of the foamed copper was 11.3 mm. Celgard 2400 type polypropylene porous membrane was used as the separator membrane. The side of the foamed copper growing copper nanowires was close to the separator membrane.

[0158] The ambient temperature was set to 25 °C. The button cell was cycled at a current density of 1 mA / cm 2 , a surface capacity of 1 mAh / cm 2 , and a charge cut-off voltage of 1 V. The cycle life was characterized by the number of cycles experienced by the button cell during the stable cycling stage, and the average coulombic efficiency during the stable cycling stage was calculated.

[0159] Performance test of symmetric cell

[0160] The button cell was assembled in the order of negative shell, spring sheet, gasket, lithium sheet, separator membrane, and the above prepared foamed copper with C and N doped copper nanowires. The button cell was discharged at a constant current of 0.5 mA / cm 2 for 10 h to deposit 5 mAh / cm 2 of metal lithium in the foamed copper with copper nanowires, and the button cell was disassembled in an argon environment to obtain foamed copper with pre-deposited lithium. The side of the foamed copper growing copper nanowires was close to the separator membrane.

[0161] A symmetric battery cell was assembled in the order of negative shell, spring sheet, gasket, pre-lithiated foam copper, separator, pre-lithiated foam copper. The electrolyte was 80 μL, the solvent was ethylene glycol dimethyl ether (DME), the lithium salt was lithium bisfluorosulfonylimide (LiFSI), and the concentration was 1 mol / L. The diameter of the foam copper was 11.3 mm. The separator was a Celgard 2400 type polypropylene porous membrane. The side of the foam copper growing copper nanowires was close to the separator.

[0162] The ambient temperature was set to 25°C. The symmetric battery cell was cycled at a current density of 1 mA / cm 2 , a surface capacity of 1 mAh / cm 2 , and the working time of the foam copper electrode was recorded in hours.

[0163] Performance test of lithium-sulfur battery cell (full battery cell)

[0164] A lithium-sulfur battery cell was assembled in the order of negative shell, spring sheet, gasket, negative electrode sheet, separator, and positive electrode sheet.

[0165] Negative electrode sheet: first assemble a button cell in the order of negative shell, spring sheet, gasket, lithium sheet, separator, and the above-prepared foam copper with C and N-doped copper nanowires, and discharge the button cell at a constant current of 0.5 mA / cm 2 for 10 h to deposit 5 mAh / cm 2 of metal lithium in the foam copper with copper nanowires, and disassemble the button cell in an argon environment to obtain pre-lithiated foam copper as the negative electrode sheet with a diameter of 16 mm.

[0166] Positive electrode sheet: use commercially available sulfur electrode sheet LS0202 with a surface density of 2.0 mg / cm 2 , the positive electrode active material is sulfur with a mass fraction of 86%; the conductive agent is Super P with a mass fraction of 7%; and the binder is polyvinylidene fluoride with a mass fraction of 7%. The positive electrode active material gram capacity is 1200 mAh / g, and the positive electrode surface capacity is 2.06 mAh / cm 2 .

[0167] The electrolyte was 80 μL, the solvent was ethylene glycol dimethyl ether (DME), the lithium salt was lithium bisfluorosulfonylimide (LiFSI), and the concentration was 1 mol / L.

[0168] The separator was a Celgard 2400 type polypropylene porous membrane. The side of the foam copper growing copper nanowires was close to the separator.

[0169] The ambient temperature was set to 25℃. The voltage range was 1.7V to 2.8V. The lithium-sulfur battery monomer was first cycled at a rate of 0.05C for 3 cycles, and then was cycled at a rate of 0.2C. The cycle life of the lithium-sulfur battery monomer was characterized by the number of cycles experienced by the lithium-sulfur battery monomer in the stable cycle stage.

[0170] Example 2

[0171] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as in Example 1, except that the reaction time of one side of the copper foam in the prepared reaction solution was adjusted from 10 min to 15 min to in-situ grow Cu(OH)2nanowire arrays on the ribbons on the surface of the copper foam.

[0172] Example 3

[0173] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as in Example 1, except that the reaction time of one side of the copper foam in the prepared reaction solution was adjusted from 10 min to 5 min to in-situ grow Cu(OH)2nanowire arrays on the ribbons on the surface of the copper foam.

[0174] Example 4

[0175] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as in Example 1, except that the reaction time of one side of the copper foam in the prepared reaction solution was adjusted from 10 min to 30 min to in-situ grow Cu(OH)2nanowire arrays on the ribbons on the surface of the copper foam.

[0176] Example 5

[0177] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as in Example 1, except that the concentration of the reaction solution was different.

[0178] The concentration of sodium hydroxide in the reaction solution was 2.5 mol / L, and the concentration of ammonium persulfate was 0.1 mol / L.

[0179] Example 6

[0180] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as in Example 1, except that the concentration of the reaction solution was different.

[0181] The concentration of sodium hydroxide in the reaction solution was 3 mol / L, and the concentration of ammonium persulfate was 0.1 mol / L.

[0182] Example 7

[0183] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as those in Example 1, except that the concentrations of the reaction solutions were different.

[0184] The concentration of sodium hydroxide in the reaction solution was 2.7 mol / L, and the concentration of ammonium persulfate was 0.08 mol / L.

[0185] Example 8

[0186] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as those in Example 1, except that the concentrations of the reaction solutions were different.

[0187] The concentration of sodium hydroxide in the reaction solution was 2.7 mol / L, and the concentration of ammonium persulfate was 0.15 mol / L.

[0188] Example 9

[0189] The preparation method of the copper foam with C and N doped copper nanowires, the preparation method of each battery monomer, and the performance test method of each battery monomer were the same as those in Example 1, except that the organic ligand was changed from 2-methylimidazole to terephthalic acid.

[0190] Comparative Example 1

[0191] The copper foam with C and N doped copper nanowires was changed to untreated copper foam.

[0192] The preparation method and performance test method of the battery monomer were as follows.

[0193] Performance test of button cell (half cell)

[0194] The button cell was assembled in the order of negative electrode shell, spring sheet, gasket, lithium sheet, separator film, and untreated copper foam. The amount of electrolyte was 80 μL, the solvent was ethylene glycol dimethyl ether (DME), the lithium salt was lithium bisfluorosulfonylimide (LiFSI), and the concentration was 1 mol / L. The diameter of the copper foam was 11.3 mm. The separator film was a Celgard 2400 type polypropylene porous film.

[0195] The ambient temperature was set to 25℃. The button cell was tested at a current density of 1 mA / cm 2 and a capacity of 1 mAh / cm 2Cyclic stability tests were conducted at the given areal capacity, with a charging cutoff voltage of 1V. Cycle life was characterized by the number of cycles experienced by a single coin cell during the stable cycling phase, and the average coulombic efficiency during the stable cycling phase was calculated.

[0196] Performance testing of symmetrical battery cells

[0197] First, assemble the button cell in the following order: negative electrode shell, spring plate, gasket, lithium plate, separator, and untreated foamed copper. Then, apply a constant current of 0.5 mA / cm² to the button cell. 2 Deposited in untreated copper foam at 5 mAh / cm³ after 10 hours of discharge. 2 Lithium metal of a certain capacity was disassembled into coin cell under argon atmosphere to obtain pre-deposited lithium foam copper.

[0198] The symmetrical battery cell was assembled in the following order: negative electrode shell, spring sheet, gasket, pre-deposited lithium copper foam, separator, and pre-deposited lithium copper foam again. The electrolyte volume was 80 μL, the solvent was dimethyl ethylene glycol (DME), and the lithium salt was lithium bis(fluorosulfonyl)imide (LiFSI) at a concentration of 1 mol / L. The diameter of the copper foam was 11.3 mm. The separator was a Celgard 2400 type polypropylene porous membrane.

[0199] The ambient temperature was set to 25℃. The symmetrical cell was then subjected to an A / cm² pressure of 1 mA. 2 Current density, 1mAh / cm 2 Cyclic stability tests were conducted at the areal capacity, and the working time of the foamed copper electrode was recorded in hours.

[0200] Performance testing of lithium-sulfur battery cells (full cell)

[0201] Assemble the lithium-sulfur battery cell in the following order: negative electrode shell, spring sheet, gasket, negative electrode plate, separator, and positive electrode plate.

[0202] Negative electrode: First, assemble the coin cell in the following order: negative electrode shell, spring plate, gasket, lithium sheet, separator, and untreated foamed copper. Then, apply a constant current of 0.5 mA / cm² to the coin cell. 2 Deposited in copper foam at 5 mAh / cm³ after 10 hours of discharge. 2 The capacity of metallic lithium is obtained by disassembling the coin cell under argon atmosphere to obtain pre-deposited lithium copper foam, which is used as the negative electrode sheet with a diameter of 16mm.

[0203] Positive electrode: Commercially available sulfur electrode LS0202 with an areal density of 2.0 mg / cm³ is used. 2The positive active material is sulfur with a mass fraction of 86%; the conductive agent is Super P with a mass fraction of 7%; and the binder is polyvinylidene fluoride with a mass fraction of 7%. The specific capacity of the positive active material is 1200 mAh / g, and the surface capacity of the positive electrode is 2.06 mAh / cm 2 .

[0204] The amount of electrolyte is 80 μL, the solvent is ethylene glycol dimethyl ether (DME), the lithium salt is lithium bisfluorosulfonylimide (LiFSI), and the concentration is 1 mol / L.

[0205] The separator film is a Celgard 2400 type polypropylene porous film.

[0206] The ambient temperature is set to 25°C. The voltage range is 1.7 V to 2.8 V. The lithium-sulfur battery monomer is first cycled at a rate of 0.05 C for 3 cycles, and then cycled at a rate of 0.2 C. The cycle life of the lithium-sulfur battery monomer is characterized by the number of cycles experienced by the lithium-sulfur battery monomer in the stable cycle stage.

[0207] From the above test results, it can be seen that the foam metal substrate with metal nanowires provided by the present disclosure can make the battery monomer have high cycle stability and long cycle life.

[0208] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same technical idea and substantially the same function and effect 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

1. A battery cell comprising a negative electrode sheet, wherein the negative electrode sheet comprises a foam metal substrate and metal nanowires on the struts of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate; the foam metal substrate comprises a metal element M; the metal nanowires comprise metal element M nanowires doped with an element A, the element A comprising C.

2. The battery cell of claim 1, wherein, the metal nanowires are also on the struts of the pore walls in the region from the surface to 0.25 times the thickness of the foam metal substrate.

3. The battery cell of any one of claims 1-2, wherein, the element A further comprises N.

4. The battery cell of claim 3, wherein, the foam metal substrate comprises a foam copper, and the metal nanowires comprise C and N doped copper nanowires.

5. The battery cell of any one of claims 1-4, wherein, The total mass fraction of the element C, the element N and the element M in the metal nanowires is 89%-100%, based on the mass of the metal nanowires.

6. The battery cell of any one of claims 1-5, wherein, The mass fraction of the element M in the metal nanowires is 70%-85%, based on the mass of the metal nanowires.

7. The battery cell of any one of claims 1-6, wherein, The metal nanowires satisfy one or more of the following conditions (1) to (3): (1) the length of the metal nanowires is 3μm-18μm; (2) the diameter of the metal nanowires is 0.14μm-0.70μm; (3) the aspect ratio of the metal nanowires is 8-70.

8. The battery cell of claim 7, wherein, The aspect ratio of the metal nanowires is 10-40.

9. The battery cell of any one of claims 1-8, wherein, The negative electrode sheet satisfies one or more of the following conditions (1) to (5): (1) the thickness of the negative electrode sheet is 80μm-180μm; (2) the porosity of the negative electrode sheet is 72%-86%; (3) the pore size distribution range of the negative electrode sheet is 35μm-206μm; (4) the through hole rate of the negative electrode sheet is greater than or equal to 98%; (5) the strut diameter distribution range of the negative electrode sheet is 10μm-51μm.

10. The battery cell of any one of claims 1-9, wherein, The negative electrode sheet further comprises an alkali metal on at least part of the metal nanowires, the alkali metal comprising one or both of Li and Na. 11.A battery device comprising the battery cell of any one of claims 1-10. 12.An electric device comprising the battery cell of any one of claims 1-10 or the battery device of claim 11. 13.A method for preparing a negative electrode sheet, comprising the following steps: providing a foam metal substrate, the foam metal substrate comprising a metal element M; growing hydroxide nanowires of the metal element M on the struts of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate to obtain a foam metal substrate with hydroxide nanowires of the metal element M; reacting the obtained foam metal substrate with hydroxide nanowires of the metal element M with a solution comprising an organic ligand to grow a metal organic framework compound of the metal element M on the surface of the hydroxide nanowires of the metal element M, to obtain a foam metal substrate with a metal organic framework compound of the metal element M; subjecting the obtained foam metal substrate with a metal organic framework compound of the metal element M to annealing treatment and reduction treatment to obtain a negative electrode sheet, The negative electrode sheet includes a foam metal substrate and metal nanowires on a rib on at least one surface of the foam metal substrate in a thickness direction of the foam metal substrate, the metal nanowires including element A-doped metal element M nanowires, the element A including C.

14. The production method according to claim 13, wherein The organic ligand has any one of N heterocyclic structure, amine group structure, carboxyl group structure, phenol group structure or a combination structure of two or more thereof.

15. The method of manufacturing according to claim 14, wherein, The organic ligand includes one or more of imidazole, 2-methylimidazole, N-methylimidazole, 1-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-propylimidazole, benzimidazole, 2-methylbenzimidazole, 2-aminobenzimidazole, 3,3',5,5'-tetra(1H-imidazol-1-yl)-1,1'-biphenyl, 1H-imidazole-4-carboxylic acid, tris(4-(1-imidazolyl)phenyl)amine, 2-(diphenylphosphino)-1-methyl-1H-imidazole, 1-hydroxy-2-(1H-imidazol-1-yl)ethane-1,1-bisphosphonic acid, phenyl bis-1H-imidazol-1-ylphosphonate, 2-(dicyclohexylphosphino)-1-(2,4,6-trimethyl-phenyl)-1H-imidazole, 3-(diphenylphosphino)-2-methylimidazo[1,2-A]pyridine, pyrazole, 3-methylpyrazole, 5-methylpyrazole, 1,3-dimethylpyrazole, 3,5-dimethylpyrazole, 1,5-dimethylpyrazole, phenylpyrazole, 1,4-di(1H-pyrazol-4-yl)benzene, pyridine, 2-methylpyridine, 3-ethylpyridine, 3-propylpyridine, 3-butylpyridine, 3-isobutylpyridine, 3-(tert-butyl)pyridine, 1,3-dimethylpyridine, 2,6-dimethylpyridine, 2-aminopyridine, 4,4-bipyridine, 2,2'-bipyridine, 4-phenylterpyridine, 4-methylphenylterpyridine, 4-carboxyphenylterpyridine, 4-nitrophenylterpyridine, 3,5-bis(1-imidazolyl)pyridine, 3,5-bis(1-benzimidazolyl)pyridine, 5-(4-pyridyl)-1,3-oxazole, thiazole, thiazolidine-2,4-dicarboxylic acid, oxazole, pyrimidine, 1,3,5-triazine, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 1,2,4,5-tetrazine, pyridazine, pyrazine, p-phenylenediamine, p-xylylenediamine, aniline, terephthalic acid, 2-amino terephthalic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, isophthalic acid, 1,3,5-benzenetricarboxylic acid, fumaric acid, triphenylene-2,6,10-tricarboxylic acid, 1,3,5-tris(4'-carboxy[1,1'-biphenyl]-4-yl)benzene, benzimidazole-4-carboxylic acid, benzoxazole-5-carboxylic acid, p-phenylpyridine-2,5-dicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 3,6-dicarboxypyridazine, 2,5-pyrimidinedicarboxylic acid, 1,2,4-triazine-3,6-dicarboxylic acid, 1,2,4,5-tetrazine-3,6-dicarboxylic acid, hydroquinone, 2,5-dihydroxyphenol.

16. The method of making according to any one of claims 13-15, wherein, The step of growing the hydroxide nanowires of the metal element M on the filaments of at least one surface of the foam metal substrate along the thickness direction of the foam metal substrate itself includes the following steps: immersing the foam metal substrate at least partially in an aqueous solution containing a strong base and a persulfate salt to react, and drying after taking out to obtain a foam metal substrate with metal element M hydroxide nanowires, the strong base includes one or both of sodium hydroxide and potassium hydroxide, and the persulfate salt includes one or more of ammonium persulfate, sodium persulfate, and potassium persulfate.

17. The preparation method of claim 16, wherein, the concentration of the strong base is 1.5 mol / L-3.5 mol / L; and / or, the concentration of the persulfate salt is 0.05 mol / L-0.2 mol / L; and / or, immersing the foam metal substrate at least partially in an aqueous solution containing a strong base and a persulfate salt to react for 5 min-30 min.

18. The method of making according to any one of claims 13-17, wherein, The step of annealing the obtained foam metal substrate with metal element M metal organic framework compound satisfies one or more of the following conditions (1) to (3): (1) the atmosphere of the annealing treatment is a protective gas atmosphere; (2) the temperature of the annealing treatment is 200℃-400℃; (3) the time of the annealing treatment is 0.5h-3.5h.

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