Composite material, method for preparing the same, positive electrode sheet, battery cell, battery, and electric device

Abstract

The application discloses a composite material and a preparation method thereof, a positive electrode sheet, a battery cell, a battery and a power utilization device, and belongs to the technical field of batteries.The composite material comprises a lithium-containing compound, a catalyst and a carbon material, wherein the carbon material has a hollow tubular structure, and the lithium-containing compound and the catalyst are arranged in the tubular structure; the lithium-containing compound comprises lithium elements, carbon elements and oxygen elements; and the catalyst comprises at least one of an oxide of a transition metal, a carbide of the transition metal or a nitride of the transition metal.The technical scheme of the application can improve the capacity of the battery cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a composite material and a preparation method thereof, a positive electrode sheet, a battery monomer, a battery and a power utilization device. BACKGROUND

[0002] With the increasing environmental pollution, new energy industry is attracting more and more attention. In the new energy industry, battery technology is an important factor for its development.

[0003] The development of battery technology needs to consider many design factors, such as capacity, energy density, cycle life, reliability, etc. In the first charge-discharge process of the battery monomer, a solid electrolyte interface SEI film will be produced on the surface of the negative electrode. The existence of the SEI film will consume a large amount of lithium ions, affecting the capacity of the battery monomer. Therefore, how to provide a composite material to supplement lithium ions and improve the capacity of the battery monomer is an urgent technical problem to be solved. SUMMARY

[0004] The present application is carried out in view of the above-mentioned problems, and the purpose is to provide a composite material to improve the capacity of the battery monomer.

[0005] In order to achieve the above-mentioned purpose, the present application provides a composite material and a preparation method thereof, a positive electrode sheet, a battery monomer, a battery and a power utilization device.

[0006] In a first aspect, a composite material is provided, comprising: a lithium-containing compound, a catalyst and a carbon material, wherein the carbon material has a hollow tubular structure, the lithium-containing compound and the catalyst are arranged in the tubular structure; the lithium-containing compound comprises lithium element, carbon element and oxygen element; the catalyst comprises at least one of oxide of transition metal, carbide of transition metal or nitride of transition metal.

[0007] In the embodiments of the present application, the lithium-containing compound can decompose to produce lithium ions and gas, so as to supplement lithium ions to the battery; the catalyst can catalyze the decomposition of the lithium-containing compound; the carbon material has a hollow tubular structure, and the lithium-containing compound and the catalyst are located in the tubular structure, which is beneficial to improve the capacity of the battery. Therefore, the technical scheme of the embodiments of the present application can improve the capacity of the battery monomer.

[0008] In a possible implementation manner, the lithium-containing compound and the catalyst are arranged on the inner wall of the tubular structure. In this way, the lithium-containing compound and the catalyst can be better arranged in the tubular structure, so as to reduce the risk of the lithium-containing compound and the catalyst separating from the tubular structure in the case of shorter composite material.

[0009] In a possible implementation, at least part of the catalyst is located on the surface of the lithium-containing compound. In this way, the catalyst can facilitate the decomposition of the lithium-containing compound.

[0010] In a possible implementation, the lithium-containing compound has a chemical formula of Li2C x O y wherein 1≤x≤4 and 3≤y≤6. Optionally, the lithium-containing compound includes at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5, or Li2C4O6. The lithium-containing compound can be decomposed into lithium ions and gas (for example, carbon monoxide or carbon dioxide) under the action of voltage and the catalyst, the lithium ions generated by the decomposition can serve to supplement lithium ions, thereby improving the capacity of the battery; the gas generated by the decomposition will not remain in the positive electrode sheet, and will not affect the long-term reliability and other performances of the battery cell due to the residues generated by the decomposition. In addition, the lithium-containing compound has good stability and can exist stably in air and organic solvents, and can be compatible with the coating process of the positive electrode slurry.

[0011] In a possible implementation, the oxide of the transition metal has a chemical formula of M α O β wherein 0<α≤3 and 0<β≤5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu, or Ti; optionally, M α O β includes at least one of NiO, Co3O4, Fe2O3, MoO3, or V2O5. The catalyst can reduce the decomposition voltage of the lithium-containing compound, so that the lithium-containing compound is decomposed at a lower voltage.

[0012] In a possible implementation, the carbide of the transition metal includes at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide, or nickel carbide; and / or, the nitride of the transition metal includes at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride, or nickel nitride. The carbide of the transition metal and the nitride of the transition metal have good catalytic effect, and can catalyze the decomposition of the lithium-containing compound.

[0013] In a possible implementation, the mass content A of the carbon material satisfies 1wt%≤A≤40wt%, based on the total mass of the composite material; optionally, A satisfies 2wt%≤A≤25wt%.

[0014] When the mass content A of the carbon material is not less than 1wt%, the carbon material can completely wrap the catalyst and the lithium-containing compound, and the conductivity of the composite material is high, which is beneficial to improve the capacity of the battery cell; when the mass content A of the carbon material is not more than 40wt%, the carbon material has a suitable mass ratio, and the catalyst and the lithium-containing compound also have a suitable mass ratio, which is beneficial to improve the capacity of the battery cell.

[0015] In a possible implementation, the mass content B of the catalyst satisfies: 0.1wt%≤B≤20wt% based on the total mass of the composite material; optionally, B satisfies: 0.5wt%≤B≤10wt%.

[0016] When the mass content B of the catalyst is not less than 0.1wt%, the contact area of the catalyst and the lithium-containing compound is suitable, and the catalyst has a good catalytic effect, which is beneficial to catalyze the decomposition of the lithium-containing compound and improve the capacity of the battery cell; when the mass content B of the catalyst is not more than 20wt%, it is beneficial to add more lithium-containing compound in the composite material and improve the capacity of the battery cell.

[0017] In a possible implementation, the mass content C of the lithium-containing compound satisfies: 45wt%≤B≤98.9wt% based on the total mass of the composite material; optionally, C satisfies: 70wt%≤B≤85wt%.

[0018] When the mass content C of the lithium-containing compound is not less than 45wt%, the content of the lithium-containing compound is more, which can generate more lithium ions, so that more lithium ions can be supplemented to the negative electrode, and the capacity of the battery cell can be improved; when the mass content C of the lithium-containing compound is not more than 98.9wt%, the carbon material and the catalyst in the composite material have a certain mass content, which is beneficial to balance the decomposition voltage of the lithium-containing compound, the conductivity of the composite material, and the number of lithium ions decomposed from the lithium-containing compound, so that a higher battery capacity can be obtained.

[0019] In a possible implementation, the aspect ratio E of the carbon material satisfies: 100:1≤E≤3000:1; optionally, E satisfies: 200:1≤E≤2000:1.

[0020] When the aspect ratio E of the carbon material is not less than 100:1, the composite material has a good conductivity effect; when the aspect ratio E of the carbon material is not more than 3000:1, on the one hand, it is beneficial to the synthesis of the carbon material, and on the other hand, it can reduce the risk of aggregation of the carbon material, thereby reducing the risk that the capacity of the battery cell is less improved due to the aggregation of the carbon material.

[0021] In a possible implementation, in the composite material, the decomposition voltage V1 of the lithium-containing compound satisfies: V1 < 4.8 V; optionally, V1 satisfies: V1 < 4.4 V. In this way, the lithium-containing compound can be decomposed at a lower voltage to supplement lithium to the negative electrode, which can reduce the risk of high voltage causing the structure of the positive electrode active material to change, and is beneficial to improving the stability and cycle performance of the battery cell.

[0022] In a possible implementation, the resistivity P of the composite material satisfies: 0.2 Ω·cm < P < 101 Ω·cm; optionally, P satisfies: 0.2 Ω·cm < P < 5.5 Ω·cm. In this way, the composite material has a suitable resistivity, so that the positive electrode plate has a suitable conductivity, and the battery cell has a more suitable capacity.

[0023] In a possible implementation, the average volume particle size Dv 1 50 of the lithium-containing compound is greater than the average volume particle size Dv 2 50 of the catalyst, so that the catalyst is attached to the surface of the lithium-containing compound, and the decomposition of the lithium-containing compound is facilitated. Optionally, the average volume particle size Dv 1 50 of the lithium-containing compound satisfies: 100 nm ≤ Dv 1 50 < 1000 nm, and the average volume particle size Dv 2 50 of the catalyst satisfies: 50 nm ≤ Dv 2 50 < 500 nm. In this way, it is beneficial to increase the specific surface area of the lithium-containing compound and the catalyst, and to increase the contact area of the lithium-containing compound and the catalyst, so as to improve the catalytic decomposition effect of the catalyst on the lithium-containing compound. In addition, since the catalytic effect of the catalyst is improved, the requirement for the mass ratio of the catalyst in the composite material is reduced, and in the case that the catalyst has a smaller mass content, the decomposition voltage of the lithium-containing compound can be reduced; and it is also beneficial to increase the mass content of the lithium-containing compound and the carbon material in the composite material, and to improve the energy density of the battery cell.

[0024] In a possible implementation, the average volume particle size Dv 1 50 of the lithium-containing compound is 50 nm to 1000 nm different from the average volume particle size Dv 2 50 of the catalyst. In this way, it is beneficial to adsorb the catalyst on the surface of the lithium-containing compound, so as to facilitate the decomposition of the lithium-containing compound.

[0025] In a second aspect, a method for preparing the composite material in the first aspect and any possible implementation thereof is provided, including: mixing a lithium-containing compound and a catalyst to obtain a mixed material of the lithium-containing compound and the catalyst, wherein the catalyst includes at least one of an oxide of a transition metal, a carbide of the transition metal, or a nitride of the transition metal, and the lithium-containing compound includes lithium, carbon, and oxygen; adding the mixed material of the lithium-containing compound and the catalyst into a slurry containing a polymer material to obtain an electrospinning stock solution; electrospinning the electrospinning stock solution to obtain a precursor; and calcining the precursor in an inert atmosphere to obtain the composite material. Through the above method, the composite material of the embodiments of the present application can be prepared, which is beneficial to improving the capacity of the battery cell.

[0026] In a possible implementation, the lithium-containing compound has a chemical formula of Li2CxOy. x O y wherein 1≤x≤4 and 3≤y≤6. Optionally, the lithium-containing compound includes at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5, or Li2C4O6.

[0027] In a possible implementation, the oxide of the transition metal has a chemical formula of M α O β wherein 0<α≤3, 0<β≤5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu, or Ti; optionally, M α O β includes at least one of NiO, Co3O4, Fe2O3, MoO3, or V2O5.

[0028] In a possible implementation, the carbide of the transition metal includes at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide, or nickel carbide; and / or, the nitride of the transition metal includes at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride, or nickel nitride.

[0029] In a possible implementation, the solute in the slurry containing the polymer material includes the polymer material, and the solvent in the slurry containing the polymer material is an organic solvent; optionally, the organic solvent includes N,N-dimethylformamide. The polymer material has good solubility in the organic solvent, and the polymer powder is added to the organic solvent to facilitate preparation of the above solution. N,N-dimethylformamide has good stability, and thus the above slurry has good performance.

[0030] In a possible implementation, a mass ratio D of the polymer material and the N,N-dimethylformamide satisfies: 1:20≤D≤1:1; optionally, D satisfies: 1:10≤D≤1:5. When D is not less than 1:20, the polymer material and the N,N-dimethylformamide have a suitable mass ratio, which facilitates the smooth electrospinning and reduces the difficulty of electrospinning. When D is not more than 1:1, the risk of a relatively dilute electrospinning solution caused by a relatively large amount of N,N-dimethylformamide and a relatively small amount of polymer material can be reduced, thereby reducing the risk of a composite material breaking in a subsequent calcination process. By reasonably setting the size of D, the smooth electrospinning and the preparation of the composite material can be facilitated.

[0031] In a possible implementation, the polymer material includes at least one of polyvinylpyrrolidone, polyacrylonitrile, or polyethylene oxide; optionally, the polymer material includes polyacrylonitrile.

[0032] In a possible implementation, a temperature T of the calcination satisfies: 300℃≤T≤480℃; optionally, T satisfies: 350℃≤T≤450℃. In this way, the carbonization of the polymer material can be fully achieved, and the risk of thermal decomposition of the lithium-containing compound caused by excessively high temperature can be reduced, thereby facilitating the preparation of the carbon material with the hollow tubular structure in the composite material.

[0033] In a possible implementation, the mixing of the lithium-containing compound and the catalyst to obtain the mixed material of the lithium-containing compound and the catalyst includes: mixing the lithium-containing compound and the catalyst and performing high-energy ball milling to obtain the mixed material of the lithium-containing compound and the catalyst. Through high-energy ball milling, the lithium-containing compound and the catalyst with a smaller particle size can be obtained, which facilitates the mixing of the lithium-containing compound and the catalyst to be more uniform and facilitates the improvement of the specific surface area of the lithium-containing compound and the catalyst, thereby facilitating the improvement of the catalytic effect of the catalyst.

[0034] In a possible implementation, a ball-to-material ratio F of the high-energy ball milling satisfies: 10:1≤F≤15:1; and / or, a revolving speed R1 of the high-energy ball milling satisfies: 1000r / min≤R1≤1500r / min; and / or, a rotating speed R2 of the high-energy ball milling satisfies: 2500r / min≤R2≤3000r / min. In this way, the high-energy ball milling has suitable process parameters, and the lithium-containing compound and the catalyst with a suitable particle size can be obtained.

[0035] In a possible implementation, a mass ratio K of the lithium-containing compound and the catalyst satisfies: 15:1≤K≤40:1. In this way, the lithium-containing compound and the catalyst have a suitable mass ratio, and the lithium-containing compound can be more fully decomposed under the catalysis of the catalyst, thereby facilitating the improvement of the capacity of the battery cell.

[0036] In a possible implementation, the average volume particle size Dv 1 50 of the lithium-containing compound is greater than the average volume particle size Dv 2 50 of the catalyst; the average volume particle size Dv 1 50 of the lithium-containing compound satisfies: 100 nm≤Dv 1 50≤1000 nm; and the average volume particle size Dv 2 50 of the catalyst satisfies: 50 nm≤Dv 2 50≤500 nm.

[0037] In a possible implementation, in the electrospinning, the voltage is 15 kV, the propelling speed of the electrospinning stock solution is 0.2 mL / min, the receiving distance is 15 cm, and the spinning time is 12 h. In this way, by means of appropriate preparation process parameters, the preparation of the composite material is facilitated.

[0038] In a third aspect, a positive electrode tab is provided, comprising a positive electrode active material; the composite material in the first aspect and any possible implementation thereof, and / or the composite material prepared by the method in the second aspect and any possible implementation thereof.

[0039] In a possible implementation, the resistance R of the positive electrode tab satisfies: 0.3 Ω < R < 0.5 Ω. In this way, the positive electrode tab has appropriate electrical conductivity, and the battery cell has appropriate capacity.

[0040] In a fourth aspect, a battery cell is provided, comprising the positive electrode tab in the third aspect and any possible implementation thereof.

[0041] In a fifth aspect, a battery is provided, comprising the battery cell in the fourth aspect.

[0042] In a sixth aspect, an electric device is provided, comprising the battery in the fifth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0044] Figure 1 A schematic view of the composite material of an embodiment of the present application;

[0045] Figure 2 A schematic view of the method for preparing the composite material of an embodiment of the present application;

[0046] Figure 3 This is a schematic diagram of a battery cell according to an embodiment of this application;

[0047] Figure 4 This is a schematic diagram of a battery according to an embodiment of this application;

[0048] Figure 5 This is a schematic diagram of an electrical device according to an embodiment of this application. Detailed Implementation

[0049] The accompanying drawings provide a detailed description of the composite materials and their preparation methods, positive electrode sheets, battery cells, batteries, and embodiments of the electrical devices described in this application. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0050] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0051] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0052] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0053] If not otherwise specified, all steps of the present application can be performed in sequence or randomly, preferably in sequence. For example, the method comprising steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method further comprising step (c) means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0054] The development of battery technology needs to consider various design factors, such as capacity, energy density, cycle life, reliability, etc. During the first charge-discharge process of the battery cell, a solid electrolyte interface (SEI) film will be produced on the surface of the negative electrode. The existence of the SEI film will consume a large amount of lithium ions, affecting the capacity of the battery cell. In order to improve the capacity of the battery cell, an additive is added to the positive electrode slurry. The additive includes Li2C2O4 and Ni x O, wherein 0.67≤x≤1. Under the catalysis of Ni x O, the Li2C2O4 in the additive can produce lithium ions under low voltage conditions, complete the lithium supplement of the negative electrode, and at the same time reduce the risk of irreversible structural changes of the positive electrode active material under high charging voltage conditions. However, after the decomposition of Li2C2O4, holes will be left at the original position of Li2C2O4, which will destroy the conductive network of the positive electrode plate, affect the ion and electron transmission, and is not conducive to improving the capacity of the battery cell. In addition, the conductivity of Li2C2O4 is poor, which is not conducive to improving the capacity of the battery cell.

[0055] Therefore, the composite material of the present application can improve the capacity of the battery.

[0056] The composite material in the present application can be used as a lithium supplement agent, that is, it can supplement the lithium ions consumed by the negative electrode. As an example, the composite material can be mixed with the positive electrode active material to prepare a positive electrode slurry for use.

[0057] The battery cell in the present application can be used as a minimum unit of the battery. The battery cell includes a positive electrode plate, a negative electrode plate, a separator, an electrolyte, etc.

[0058] [Composite material]

[0059] Figure 1 A schematic view of a composite material according to an embodiment of the present application. As shown in FIG. 1, the composite material 1 includes a lithium-containing compound 11, a catalyst 12, and a carbon material 13. Figure 1

[0060] The carbon material 13 has a hollow tubular structure, and the lithium-containing compound 11 and the catalyst 12 are arranged inside the tubular structure.

[0061] The lithium-containing compound 11 and the catalyst 12 can be arranged inside the tubular structure and not in contact with the inner wall of the tubular structure, or can be arranged on the inner wall of the tubular structure.

[0062] The carbon material 13 is a carbon tube, for example, a carbon tube at the nanometer level. The carbon material 13 has a fiber-like shape, and the carbon material 13 can continuously extend in different directions.

[0063] The carbon material 13 can be an amorphous carbon material. In some embodiments, the carbon material 13 is a completely carbonized polymer material, that is, the carbon material 13 can only include carbon elements.

[0064] The lithium-containing compound 11 and the catalyst 12 are arranged inside the tubular structure of the carbon material 13, that is, the lithium-containing compound 11 and the catalyst 12 are coated inside the carbon material 13, and the lithium-containing compound 11 and the catalyst 12 are not in direct contact with the outside (for example, the positive active material).

[0065] Since the lithium-containing compound 11 is located inside the tubular structure of the carbon material 13, after the lithium-containing compound 11 decomposes, the holes or vacancies left by the original position of the lithium-containing compound 11 will not directly affect the positive electrode sheet, thus reducing the risk of the conductive network of the positive electrode sheet being damaged, and having less impact on the transmission of electrons and ions in the positive electrode sheet, thereby improving the capacity of the battery cell. In addition, the vacancies left on the inner wall of the tubular structure of the carbon material 13 after the decomposition of the lithium-containing compound 11 can enhance the infiltration of the electrolyte, and the electrolyte on the vacancies can provide a channel for ion transmission, thereby facilitating the transmission of ions (such as lithium ions), and thus improving the capacity of the battery.

[0066] The carbon material 13 has good electrical conductivity, and by adding the carbon material 13 to the composite material 1, it is beneficial to reduce the resistivity of the composite material 1 and improve the capacity of the battery cell.

[0067] The lithium-containing compound 11 includes lithium elements, carbon elements, and oxygen elements. The lithium-containing compound 11 can include organic lithium-containing compounds, such as Li2C2O4, or inorganic lithium-containing compounds, such as Li2CO3.

[0068] ​Lithium-containing compound 1 can decompose under voltage, breaking down into lithium ions and carbon oxides (such as CO and CO2). The lithium ions produced during decomposition can replenish the negative electrode, thereby improving the battery capacity.

[0069] Catalyst 12 comprises at least one of a transition metal oxide, a transition metal carbide, or a transition metal nitride. Catalyst 12 can reduce the decomposition voltage of lithium-containing compound 11.

[0070] Transition metal carbides and transition metal nitrides can be obtained by processing transition metal oxides. Transition metal carbides can be molybdenum carbide or tungsten carbide, and transition metal nitrides can be molybdenum nitride or manganese nitride.

[0071] Transition metal oxides, transition metal carbides, and transition metal nitrides not only have high electrical conductivity, but also possess abundant surface active sites and high specific surface area, which can catalyze the decomposition of lithium-containing compounds.

[0072] Oxides, carbides, and nitrides of transition metals can catalyze the decomposition of lithium compound 11 under voltage, that is, they can reduce the decomposition voltage of lithium compound 11.

[0073] As an example, the catalyst is an oxide of a transition metal, such as Ni. x O, where 0.67≤x≤1, and the embodiments of this application include but are not limited to this, as long as it can catalyze the decomposition of lithium-containing compounds.

[0074] Composite material 1 is a fibrous material, and composite material 1 has the same shape as carbon material 13.

[0075] In this embodiment, the lithium-containing compound 11 decomposes under voltage to generate lithium ions and gas, thereby replenishing the battery with lithium ions. The catalyst 12 catalyzes the decomposition of the lithium-containing compound 11, allowing it to decompose at a lower voltage, thus making it compatible with various positive electrode active materials. The carbon material 13 has a hollow tubular structure, with the lithium-containing compound 11 and catalyst 12 located within it. This reduces the risk of vacancies left after the decomposition of the lithium-containing compound 11 damaging the conductive network of the electrode, resulting in better ion and electron transport performance, which is beneficial for increasing the capacity of the battery cell. Furthermore, the vacancies left by the lithium-containing compound 11 in the tubular structure of the carbon material 13 also help increase the wettability of the electrolyte, which is beneficial for ion transport, further improving the battery capacity. Therefore, the technical solution of this embodiment can improve the capacity of the battery cell.

[0076] In some embodiments, the lithium-containing compound 11 and the catalyst 12 are disposed on the inner wall of the tubular structure. In this way, the lithium-containing compound and the catalyst can be better disposed in the tubular structure, thereby reducing the risk of the lithium-containing compound and the catalyst escaping from the tubular structure in the case of a shorter composite material.

[0077] In some embodiments, at least part of the catalyst 12 is located on the surface of the lithium-containing compound 11. In this way, the catalyst 12 located on the surface of the lithium-containing compound 11 can catalyze the decomposition of the lithium-containing compound 11, thereby reducing the decomposition voltage of the lithium-containing compound 11.

[0078] In the composite material 1, part of the catalyst 12 can be located on the surface of the lithium-containing compound 11, but inside the tubular structure of the carbon material 13; or all of the catalyst 12 can be located on the surface of the lithium-containing compound 11.

[0079] In some embodiments, the chemical formula of the lithium-containing compound 11 is Li2C x O y , wherein 1≤x≤4 and 3≤y≤6.

[0080] For the chemical formula Li2C x O y , x and y satisfy the following relationship: x+y=2n, 2≤n≤5.

[0081] , wherein x can be 1, 2, 3, 4, or any value within the above range, y can be 3, 4, 5, 6, or any value within the above range, and n can be 2, 3, 4, 5, or any value within the above range. As an example, x, y, and n are all positive integers.

[0082] The lithium-containing compound 11 described above can be decomposed into lithium ions and gas (e.g., carbon monoxide, carbon dioxide) under the action of voltage and the catalyst 12. The lithium ions generated by decomposition can serve to supplement lithium ions, which is conducive to improving the capacity of the battery. The gas generated by decomposition does not remain in the positive electrode sheet and does not affect the long-term reliability and other properties of the battery cell due to the residues generated by decomposition. In addition, the lithium-containing compound 11 described above has good stability and can stably exist in air and organic solvents, and can be compatible with the coating process of the positive electrode slurry.

[0083] As an example, the gas generated by the decomposition of the lithium-containing compound 11 can be sucked out of the battery cell by a suction nozzle or other tool during the formation step.

[0084] In some embodiments, the lithium-containing compound 11 includes at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5, or Li2C4O6. The lithium-containing compound described above is relatively easy to obtain and is convenient to apply in the composite material 1.

[0085] In some embodiments, the oxide of the transition metal has a chemical formula of M α O β wherein 0 < a ≤ 3, 0 < β ≤ 5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu, or Ti.

[0086] a can be 0.5, 1, 2, 3, or any value within the above range, and β can be 0.5, 1, 2, 3, 4, 5, or any value within the above range. In some examples, a and β are positive integers.

[0087] The catalyst 12 described above can reduce the decomposition voltage of the lithium-containing compound 11, so that the lithium-containing compound 11 decomposes at a lower voltage.

[0088] In some embodiments, the oxide of the transition metal has a chemical formula of M α O β includes at least one of NiO, Co3O4, Fe2O3, MoO3, or V2O5. The catalyst described above is easy to obtain and is convenient to apply to the composite material 1.

[0089] In some embodiments, the carbide of the transition metal includes at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide, or nickel carbide; and / or, the nitride of the transition metal includes at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride, or nickel nitride. The carbide of the transition metal and the nitride of the transition metal described above have good catalytic effects and can catalyze the decomposition of the lithium-containing compound.

[0090] In some embodiments, the mass content A of the carbon material 13 satisfies 1wt% ≤ A ≤ 40wt% based on the total mass of the composite material 1.

[0091] A can be 1wt%, 10wt%, 15wt%, 25wt%, 30wt%, 35wt%, 40wt%, or any value within the above range.

[0092] When the mass content A of the carbon material 13 is not less than 1wt%, the carbon material 13 can completely wrap the catalyst 12 and the lithium-containing compound 11, and the composite material 1 has high electrical conductivity, which is conducive to improving the capacity of the battery cell; when the mass content A of the carbon material 13 is not more than 40wt%, the carbon material 13 has a suitable mass proportion, and the catalyst 12 and the lithium-containing compound 11 also have suitable mass proportions, which is conducive to improving the capacity of the battery cell.

[0093] In this embodiment, by setting A to satisfy 1wt% ≤ A ≤ 40wt%, the battery cell has high capacity.

[0094] In some embodiments, A satisfies: 2wt%≤A≤25wt%. In this way, the battery cell can balance higher conductivity and higher capacity.

[0095] In some embodiments, the mass content B of the catalyst 12 satisfies: 0.1wt%≤B≤20wt%, based on the total mass of the composite material 1.

[0096] B can be 0.1wt%, 0.5wt%, 1wt%, 5wt%, 8wt%, 10wt%, 15wt%, 20wt%, or any value within the above range.

[0097] In the case where the mass content B of the catalyst 12 is not less than 0.1wt%, the contact area of the catalyst 12 with the lithium-containing compound 11 is suitable, and has a good catalytic effect, thereby facilitating the decomposition of the lithium-containing compound 11 and facilitating the improvement of the capacity of the battery cell; in the case where the mass content B of the catalyst 12 is not more than 20wt%, it is beneficial to add more lithium-containing compound 11 in the composite material 1, and it is beneficial to improve the capacity of the battery cell.

[0098] In some embodiments, B satisfies: 0.5wt%≤B≤10wt%. In this way, it is beneficial to balance the capacity of the battery cell and the decomposition voltage of the lithium-containing compound 11.

[0099] In some embodiments, the mass content C of the lithium-containing compound 11 satisfies: 45wt%≤B≤98.9wt%, based on the total mass of the composite material 1; optionally, C satisfies: 70wt%≤B≤85wt%.

[0100] In the case where the mass content C of the lithium-containing compound 11 is not less than 45wt%, the content of the lithium-containing compound 11 is more, which can decompose to generate more lithium ions, thereby supplementing more lithium ions to the negative electrode, and it is beneficial to improve the capacity of the battery cell; in the case where the mass content C of the lithium-containing compound 11 is not more than 98.9wt%, the carbon material 13 and the catalyst 12 in the composite material have a certain mass content, which is beneficial to balance the decomposition voltage of the lithium-containing compound 11, the conductivity of the composite material 1, and the number of lithium ions decomposed from the lithium-containing compound 11, thereby obtaining higher battery capacity.

[0101] In some embodiments, the aspect ratio E of the carbon material 13 satisfies: 100:1≤E≤3000:1.

[0102] E can be 100:1, 200:1, 500:1, 1000:1, 1500:1, 2000:1, 3000:1, or any value within the above range.

[0103] The aspect ratio is a common knowledge in the art, has the meaning known in the art, and can be measured by the test method and instrument known in the art. The aspect ratio can refer to the ratio of the length to the diameter of the carbon material 13. Specifically, the ratio of the length to the outer diameter of the tubular structure of the carbon material 13.

[0104] When the aspect ratio E of the carbon material 13 is not less than 100:1, the composite material 1 has a better conductive effect; when the aspect ratio E of the carbon material 13 is not more than 3000:1, on the one hand, it is beneficial to the synthesis of the carbon material 13, and on the other hand, it can reduce the risk of aggregation of the carbon material 13, thereby reducing the risk that the capacity of the battery cell is less improved due to the aggregation of the carbon material 13.

[0105] In some embodiments, E satisfies: 200:1≤E≤2000:1. In this way, the battery cell has a higher capacity.

[0106] In some embodiments, in the composite material 1, the decomposition voltage V1 of the lithium-containing compound 11 satisfies: V1<4.8V; optionally, V1 satisfies: V1<4.4V. For example, V1 is 4.79V, 4.4V, 4.3V, etc.

[0107] The decomposition voltage of the lithium-containing compound 11 is a common knowledge in the art, has the meaning known in the art, and can be measured by the test method and instrument known in the art.

[0108] The lithium-containing compound 11 can be decomposed at a lower voltage to supplement lithium to the negative electrode, which can reduce the risk that the structure of the positive active material changes due to high voltage, and is beneficial to improving the stability and cycle performance of the battery cell.

[0109] In some embodiments, the resistivity P of the composite material 1 satisfies: 0.2Ω·cm

[0110] The resistivity is a common knowledge in the art, has the meaning known in the art, and can be measured by the test method and instrument known in the art.

[0111] The resistivity in the embodiments of the present application is the resistivity measured after the composite material is pressed into a sheet shape under a pressure of 20MPa. Generally, the greater the pressure, the lower the resistivity.

[0112] The composite material 1 has a suitable resistivity, so that the positive electrode sheet has a suitable conductive performance, and the battery cell has a more suitable capacity.

[0113] In some embodiments, the average volume particle size Dv 150 is greater than the average volume particle size Dv of the catalyst 12 2 50. In this way, the catalyst 12 is facilitated to adhere to the surface of the lithium-containing compound 11, thereby facilitating to improve the catalytic effect of the catalyst 12.

[0114] The average volume particle size is a common knowledge in the art, has the meaning known in the art, and can be measured by the test method and instrument known in the art.

[0115] In some embodiments, the average volume particle size Dv of the lithium-containing compound 11 1 50 is greater than the average volume particle size Dv of the catalyst 12 2 50 by 50 nm to 1000 nm. For example, Dv 1 50 is 100 nm, Dv 2 50 is 50 nm; Dv 1 50 is 500 nm, Dv 2 50 is 200 nm; or Dv 1 50 is 1000 nm, Dv 2 50 is 500 nm. Dv 1 50 and Dv 2 50 by 50 nm, 100 nm, 500 nm, 1000 nm or any value within the above range. In this way, the catalyst 12 is facilitated to adhere to the surface of the lithium-containing compound 11, thereby facilitating to improve the catalytic decomposition of the lithium-containing compound 11.

[0116] In some embodiments, the average volume particle size Dv of the lithium-containing compound 11 1 50 satisfies: 100 nm≤Dv 1 50≤1000 nm, the average volume particle size Dv of the catalyst 12 2 50 satisfies: 50 nm≤Dv 2 50≤500 nm.

[0117] In this way, the specific surface area of the lithium-containing compound 11 and the catalyst 12 is facilitated to be improved, the contact area of the lithium-containing compound 11 and the catalyst 12 is facilitated to be improved, thereby facilitating to improve the effect of the catalytic decomposition of the lithium-containing compound 11 by the catalyst 12. In addition, since the catalytic effect of the catalyst 12 is improved, the requirement for the mass ratio of the catalyst 12 in the composite material 1 is reduced, the decomposition voltage of the lithium-containing compound 11 can be reduced in the case that the catalyst 12 has a smaller mass content; and it is also facilitated to increase the mass content of the lithium-containing compound 11 and the carbon material 13 in the composite material 1, and improve the energy density of the battery cell.

[0118] The above describes the product side of the composite material of the embodiments of the present application, and the following will be described in combination with Figure 1 the product side of the composite material of the embodiments of the present application, and the following will be described in combination withFigure 2 The description of the preparation method of the composite material is described below, and the similar content can be referred to the description of the product side of the composite material, which will not be repeated here.

[0119] [Preparation method of the composite material]

[0120] Figure 2 A schematic diagram of the preparation method of the composite material according to an embodiment of the present application, which can be used to prepare the composite material in any of the above embodiments. As shown in the figure, the method 200 includes the following steps. Figure 2 The method 200 includes the following steps.

[0121] In step 210, the lithium-containing compound 11 and the catalyst 12 are mixed to obtain a mixed material of the lithium-containing compound 11 and the catalyst 12. The catalyst 12 includes at least one of an oxide of a transition metal, a carbide of a transition metal, or a nitride of a transition metal, and the lithium-containing compound 11 includes lithium, carbon, and oxygen.

[0122] In step 220, the mixed material of the lithium-containing compound and the catalyst is added to the slurry containing the polymer material to obtain an electrospinning stock solution.

[0123] For example, the polymer material is added to an organic solvent, heated and stirred until the polymer material is dissolved to obtain a slurry containing the polymer material; then, the mixed material of the lithium-containing compound 11 and the catalyst 12 is added to the above slurry to obtain an electrospinning stock solution.

[0124] As an example, the polymer material is added to a N,N-dimethylformamide (DMF) solution, heated and continuously stirred for a period of time. The heating temperature during stirring is 80°C, the heating time is 10h, and the stirring speed is 1000rpm. After the polymer material is completely dissolved, the mixed material of the lithium-containing compound 11 and the catalyst 12 prepared in step 210 is added to the DMF solution containing the dissolved polymer material, and the electrospinning stock solution is formed after sufficient stirring.

[0125] In step 230, electrospinning is performed on the electrospinning stock solution to obtain a precursor.

[0126] As an example, a coaxial electrospinning is used to obtain the precursor of the composite material.

[0127] During the electrospinning process, the polymer in the electrospinning stock solution spontaneously wraps the lithium-containing compound 11 and the catalyst 12, thereby forming a precursor completely wrapping the lithium-containing compound 11 and the catalyst 12. After calcination, the polymer in the precursor is carbonized, the DMF solution disappears, and a composite material 1 with a hollow tubular structure is formed. In the composite material 1, the lithium-containing compound 11 and the catalyst 12 can have a certain gap with the inner wall of the tubular structure of the carbon material 13.

[0128] Step 240, calcining the precursor in an inert atmosphere to obtain the composite material 1.

[0129] The precursor is calcined in an inert atmosphere, and the polymer material can be removed through a carbonization process to form a carbon material 13 with a hollow tubular structure, and the inner wall of the tubular structure of the carbon material 13 is provided with the lithium-containing compound 11 and the catalyst 12.

[0130] Through the above method 200, the composite material 1 of the embodiment of the application can be prepared, which is beneficial to improve the capacity of the battery monomer.

[0131] In some embodiments, the chemical formula of the lithium-containing compound 11 is Li2C x O y , wherein 1≤x≤4 and 3≤y≤6. Optionally, the lithium-containing compound 11 includes at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5 or Li2C4O6.

[0132] In some embodiments, the chemical formula of the oxide of the transition metal is M α O β , wherein 0<α≤3 and 0<β≤5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu or Ti; optionally, M α O β includes at least one of NiO, Co3O4, Fe2O3, MoO3 or V2O5.

[0133] In some embodiments, the carbide of the transition metal includes at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide or nickel carbide; and / or, the nitride of the transition metal includes at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride or nickel nitride.

[0134] In some embodiments, the solute in the slurry containing the polymer material includes the polymer material, and the solvent in the slurry containing the polymer material is an organic solvent; optionally, the organic solvent includes N,N-dimethylformamide. The polymer material has good solubility in the organic solvent, and after the polymer powder is added to the organic solvent, the above-mentioned solution can be prepared. N,N-dimethylformamide has good stability, so that the above-mentioned slurry has good performance.

[0135] In some embodiments, the mass ratio D of the polymer material to N,N-dimethylformamide satisfies 1:20≤D≤1:1.

[0136] D can be 1:20, 1:15, 1:10, 1:8, 1:5, 1:1, or any value within the above range. When D is not less than 1:20, the high polymer material and N,N-dimethylformamide have a suitable mass ratio, which facilitates the smooth progress of electrospinning and can reduce the difficulty of electrospinning. When D is not more than 1:1, the risk of the electrospinning stock solution being too dilute due to too much N,N-dimethylformamide and too little high polymer material can be reduced, thereby reducing the risk of the composite material breaking during the subsequent calcination process. By reasonably setting the size of D, the smooth progress of electrospinning and the preparation of the composite material 1 are facilitated, and the carbon material 13 with a suitable mass ratio can be obtained through the subsequent calcination process.

[0137] In some embodiments, D satisfies: 1:10≤D≤1:5.

[0138] In some embodiments, the high polymer material includes at least one of polyvinylpyrrolidone, polyacrylonitrile, or polyethylene oxide. As an example, the high polymer is polyacrylonitrile.

[0139] In some embodiments, the temperature T of calcination satisfies: 300℃≤T≤480℃.

[0140] T can be 300℃, 350℃, 400℃, 450℃, 480℃, or any value within the above range.

[0141] By setting the temperature T of calcination to satisfy 300℃≤T≤480℃, it is not only conducive to achieving the full carbonization of the high polymer material, but also can reduce the risk of thermal decomposition of the lithium-containing compound due to excessively high temperature, thereby facilitating the preparation of the carbon material 13 with a hollow tubular structure.

[0142] In some embodiments, T satisfies: 350℃≤T≤450℃.

[0143] In some embodiments, step 210 includes mixing the lithium-containing compound 11 and the catalyst 12 and performing high-energy ball milling to obtain a mixed material of the lithium-containing compound 11 and the catalyst 12.

[0144] High-energy ball milling refers to a method of using the rotation or vibration of ball milling to make hard balls strongly impact, grind, and stir raw materials, and to crush the powder into nano-sized particles through the shearing force between the ball millers.

[0145] As an example, a high-energy ball mill can be used to ball mill the lithium-containing compound 11 and the catalyst 12.

[0146] The lithium-containing compound 11 and the catalyst 12 obtained by high-energy ball milling have smaller particle sizes, which is beneficial to the mixing of the lithium-containing compound 11 and the catalyst 12, and is beneficial to the specific surface area and activity of the lithium-containing compound 11 and the catalyst 12, thereby improving the catalytic effect of the catalyst 12.

[0147] In some embodiments, the ball-to-material ratio F of the high-energy ball milling satisfies: 10:1≤F≤15:1; and / or, the revolving speed R1 of the high-energy ball milling satisfies: 1000r / min≤R1≤1500r / min; and / or, the rotating speed R2 of the high-energy ball milling satisfies: 2500r / min≤R2≤3000r / min. In this way, the high-energy ball milling has suitable process parameters, and the lithium-containing compound 11 and the catalyst 12 with suitable particle sizes can be obtained.

[0148] The ball-to-material ratio refers to the mass ratio of the ball mill in the ball mill tank to the material, i.e., the mass ratio of the ball mill to the mass sum of the lithium-containing compound 11 and the catalyst 12. The revolving speed can refer to the rotating speed of the main wheel disc of the ball mill; and the rotating speed can refer to the rotating speed of the ball mill tank.

[0149] F can be 10:1, 12:1, 15:1, or any value within the above range, R1 can be 1000r / min, 1200r / min, 1500r / min, or any value within the above range, and R2 can be 2500r / min, 2800r / min, 3000r / min, or any value within the above range.

[0150] In some embodiments, the mass ratio K of the lithium-containing compound 11 to the catalyst 12 satisfies: 15:1≤K≤40:1. In this way, the lithium-containing compound 11 and the catalyst 12 have a suitable mass ratio, and the lithium-containing compound 11 can be more fully decomposed under the catalytic action of the catalyst 12, which is beneficial to improving the capacity of the battery cell.

[0151] K can be 15:1, 20:1, 30:1, 40:1, or any value within the above range.

[0152] In some embodiments, the average volume particle size Dv 1 50 of the lithium-containing compound 11 is greater than the average volume particle size Dv 2 50 of the catalyst 12. Optionally, the difference between the average volume particle size Dv 1 50 of the lithium-containing compound 11 and the average volume particle size Dv 2 50 of the catalyst 12 is 50nm-1000nm.

[0153] In some embodiments, the average volume particle size Dv 1 50 of the lithium-containing compound 11 satisfies: 100nm≤Dv 150≤1000nm, the average volume particle size Dv of the catalyst 12 2 50 satisfies: 50nm≤Dv 2 50≤500nm.

[0154] In some embodiments, in the electrospinning, the voltage is 15kV, the propelling speed of the electrospinning stock solution is 0.2mL / min, the receiving distance is 15cm, and the spinning time is 12h. In this way, through appropriate preparation process parameters, the preparation of the composite material 1 is facilitated.

[0155] It should be noted that in the embodiments of the present application, other voltages, propelling speeds, receiving distances, spinning times and the like can also be set according to actual needs, and the embodiments of the present application include but are not limited to the above.

[0156] [Positive electrode sheet]

[0157] The embodiments of the present application provide a positive electrode sheet, comprising a positive electrode active material; and the composite material 1 of any one of the above embodiments, and / or the composite material 1 prepared by the method of any one of the above embodiments.

[0158] The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on the positive electrode current collector.

[0159] The positive electrode current collector can be a metal foil or a composite current collector. For example, the positive electrode current collector can be an aluminum foil.

[0160] The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0161] The positive electrode film layer comprises a positive electrode active material. The positive electrode active material can use a positive electrode active material known in the art for a battery. For example, the positive electrode active material is lithium iron phosphate, ternary material, lithium-rich manganese-based material, etc.

[0162] The positive electrode film layer can also optionally comprise a binder. As an example, the binder can comprise at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylic ester resin.

[0163] The positive electrode film layer can also optionally include a conductive agent. 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.

[0164] In some embodiments, the resistance R of the positive electrode tab satisfies: 0.3 Ω < R < 0.5 Ω. In this way, the positive electrode tab has suitable electrical conductivity, and the battery cell has suitable capacity.

[0165] [Positive electrode tab]

[0166] The negative electrode tab includes a negative electrode current collector and a negative electrode film layer disposed on the negative electrode current collector.

[0167] The negative electrode current collector can be a metal foil or a composite current collector. The negative electrode current collector can be a copper foil. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0168] The negative electrode film layer includes a negative electrode active material. The negative electrode active material can be any known negative electrode active material for a battery. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, etc. The silicon-based material can include at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can include at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery can also be used. These negative electrode active materials can be used alone or in combination with two or more.

[0169] The negative electrode film layer can also optionally include a conductive agent. 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.

[0170] [Electrolyte]

[0171] The electrolyte functions to conduct ions between the positive electrode tab and the negative electrode tab. The type of electrolyte is not specifically limited in the embodiments of the present application, and can be selected as needed. For example, the electrolyte can be liquid, gel, or all-solid.

[0172] In some embodiments, the electrolyte is an electrolytic solution. The electrolytic solution includes an electrolyte salt and a solvent.

[0173] The electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalato borate, lithium di oxalato borate, lithium difluoro di oxalato phosphate, and lithium tetrafluoro oxalato phosphate.

[0174] The solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0175] The electrolyte can also optionally include a negative electrode film-forming additive, a positive electrode film-forming additive, and can also include performance additives that can improve certain performance of the battery, such as performance additives that improve overcharge performance of the battery, improve high or low temperature performance of the battery, etc.

[0176] [Separator]

[0177] The separator is used to separate the positive electrode sheet and the negative electrode sheet. The type of the separator is not particularly limited in the embodiments of the present application, and any known porous structure separator having good chemical stability and mechanical stability can be selected.

[0178] The material of the separator can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of the layers can be the same or different, and are not particularly limited.

[0179] The positive electrode sheet, the negative electrode sheet, and the separator can be made into an electrode assembly through a winding process or a stacking process.

[0180] [Battery cell]

[0181] The embodiments of the present application provide a battery cell, which includes the positive electrode sheet in the above embodiments.

[0182] The battery cell of the embodiments of the present application can be a battery cell that has not undergone charging and discharging. For example, the battery cell is a battery cell that has just been assembled and has not been used. For example, the battery cell is a battery cell that has not undergone a formation process.

[0183] After the battery cell is assembled and used for a period of time, the lithium-containing compound 11 of the composite material 1 in the electrode sheet in the battery cell decomposes, and only a small amount or none of the lithium-containing compound 11 exists in the electrode sheet.

[0184] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. The battery cell can be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, a magnesium-ion battery, etc.

[0185] Figure 3 This is a schematic diagram of a battery cell according to an embodiment of this application. For example, such as... Figure 3 As shown, the battery cell 3 is a square battery cell. The battery cell 3 includes a housing 31, an end cap assembly 32, and an electrode assembly 33 disposed in the housing 31.

[0186] The electrode assembly 33 can be made from a positive electrode, a negative electrode, and a separator through a winding process or a stacking process.

[0187] End cap assembly 32 includes electrode terminals 322, such as... Figure 3 As shown, the end cap assembly 32 includes two electrode terminals 322, one of which is a positive electrode terminal and the other is a negative electrode terminal.

[0188] The battery cell 3 also includes a current collector 34, which is used to connect the tab 331 of the electrode assembly 33 and the electrode terminal 322. For example, in the case that the electrode 1 in this embodiment is a positive electrode, one current collector 34 is used to connect the positive electrode tab (which may also be the tab 102 of the electrode 1) and the positive electrode terminal, and another current collector 34 is used to connect the negative electrode tab and the negative electrode terminal.

[0189] In some embodiments, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0190] [Battery]

[0191] This application provides a battery, including the battery cell described in the above embodiments. Figure 4 This is a schematic diagram of a battery according to an embodiment of this application. Figure 4 As shown, battery 5 may include multiple battery cells (not shown in the figure).

[0192] Battery cells 3 can be directly assembled into battery 5, or they can be first assembled into battery modules, and then multiple battery modules can be assembled into battery 5.

[0193] [Electrical appliances]

[0194] This application provides an electrical device, including the battery described in the above embodiments.

[0195] Figure 5 This is a schematic diagram of an electrical device according to an embodiment of this application. Figure 5As shown, the application provides a power consuming device 6, including the battery in the above embodiments.

[0196] Optionally, the power consuming device can also be an energy storage device, a lighting device, a spacecraft, etc., and the embodiments of the application include but are not limited to the above.

[0197] Hereinafter, the embodiments of the application will be described. The embodiments described below are exemplary and are only used to explain the application and cannot be understood as a limitation of the application. If a specific technology or condition is not specified in the embodiments, the technology or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be obtained by market purchase.

[0198] [Embodiments]

[0199] Embodiment 1

[0200] In the process of preparing the composite material, the mass ratio K of the lithium-containing compound to the catalyst is 17:1, the average volume particle size Dv 1 50 of the lithium-containing compound is 500 nm, the average volume particle size Dv 2 50 of the catalyst is 200 nm, the high polymer material is polyacrylonitrile, the mass ratio of the high polymer material to DMF is 1:10, and the calcination temperature T is 400°C.

[0201] In the prepared composite material, the mass content A of the carbon material is 10wt%, the mass content B of the catalyst is 5wt%, and the mass content C of the lithium-containing compound is 85wt%. The aspect ratio E of the carbon material is 1500:1, the decomposition voltage V1 of the lithium-containing compound is 4.35V, and the powder resistivity P of the composite material is 0.21Ω·cm.

[0202] Embodiments 2-5

[0203] Embodiments 2-5 are different from Embodiment 1 in that the mass content A of the carbon material is different.

[0204] The mass content of the carbon material is related to the amount of the high polymer material added in the preparation process. The more the high polymer material added, the greater the mass content A of the carbon material. The mass content of the added high polymer material can be calculated from the mass content of the carbon material.

[0205] Embodiments 6-9

[0206] Embodiments 6-9 are different from Embodiment 1 in that the mass content B of the catalyst is different.

[0207] Embodiments 10-13

[0208] Embodiments 10-13 are different from Embodiment 1 in that the aspect ratio E of the carbon material is different.

[0209] Examples 14-17

[0210] Examples 14-17 differ from Example 1 in that the mass ratio of the high molecular material to DMF is different.

[0211] Examples 18-21

[0212] Examples 18-21 differ from Example 1 in that the calcination temperature T is different.

[0213] Examples 22-24

[0214] Examples 22-24 differ from Example 1 in that the average volume particle size Dv 1 50 of the lithium-containing compound is different. 2 50 of the catalyst is different.

[0215] Examples 25-27

[0216] Examples 25-27 differ from Example 1 in that the type of the lithium-containing compound is different.

[0217] Examples 28-29

[0218] Examples 28-29 differ from Example 1 in that the type of the catalyst is different.

[0219] Example 30

[0220] Example 30 differs from Example 1 in that the mass ratio of the carbon material and the catalyst is low, and the aspect ratio of the carbon material is low.

[0221] Example 31

[0222] Example 31 differs from Example 1 in that the mass ratio of the carbon material is high, and the mass ratio of the high molecular material to DMF is high.

[0223] Example 32

[0224] Example 32 differs from Example 1 in that the mass ratio of the catalyst is high, and the calcination temperature is high.

[0225] Example 33

[0226] Example 33 differs from Example 1 in that the aspect ratio of the carbon material is high, the mass ratio of the high molecular material to DMF is low, and the calcination temperature is low.

[0227] Examples 34-35

[0228] Examples 34-35 differ from Example 1 in that the catalyst is a carbide of a transition metal and a nitride of a transition metal, respectively.

[0229] Example 36

[0230] Example 36 differs from Example 1 in that lithium iron phosphate (LFP) is added as a positive active material during the preparation of the positive electrode sheet.

[0231] Comparative Example 1

[0232] Comparative Example 1 differs from Example 1 in that the material is not a composite material, but only a lithium-containing compound.

[0233] Comparative Example 2

[0234] Comparative Example 2 differs from Example 1 in that the material is a mixture of a lithium-containing compound and a catalyst.

[0235] Comparative Example 3

[0236] Comparative Example 3 differs from Example 1 in that the material is a carbon-coated lithium-containing compound.

[0237] Comparative Example 4

[0238] Comparative Example 4 differs from Example 25 in that the material is not a composite material, but only a lithium-containing compound.

[0239] Comparative Example 5

[0240] Comparative Example 5 differs from Example 26 in that the material is not a composite material, but only a lithium-containing compound.

[0241] Comparative Example 6

[0242] Comparative Example 6 differs from Example 27 in that the material is not a composite material, but only a lithium-containing compound.

[0243] Comparative Example 7

[0244] Comparative Example 7 differs from Example 36 in that the added material is not a composite material, but only a lithium-containing compound.

[0245] Comparative Example 8

[0246] Comparative Example 8 differs from Example 36 in that the added material is a mixture of a lithium-containing compound and a catalyst.

[0247] Comparative Example 9

[0248] Comparative Example 9 differs from Example 36 in that the added material is a carbon-coated lithium-containing compound.

[0249] In combination with Tables 1 and 2, lithium-ion battery cells were prepared in Examples 1-34 and Comparative Examples 1-6 using a composite material as a positive active material.

[0250] In Table 1 and Table 3, A is the mass content of the carbon material, B is the mass content of the catalyst, C is the mass content of the lithium-containing compound, K is the mass ratio of the lithium-containing compound to the catalyst, D v 1 50 is the average volume particle size of the lithium-containing compound, D v 2 50 is the average volume particle size of the catalyst, E is the mass ratio of the carbon material, D is the mass ratio of the polymer material to DMF, and T is the calcination temperature. In Table 2 and Table 3, V1 is the decomposition voltage of the lithium-containing compound, P is the powder resistivity of the composite material, Q is the first cycle charge capacity of the battery cell, and R is the membrane resistance after the electrode sheet is fully charged.

[0251] Parameters of examples and comparative examples in Table 1

[0252]

[0253]

[0254] Experimental results of comparative examples and examples in Table 2

[0255]

[0256]

[0257] [Preparation of battery cell]

[0258] (1) Preparation of positive electrode sheet: the composite material, the binder polyvinylidene fluoride (PVDF), and the conductive agent (acetylene black) were dissolved in the solvent N-methyl pyrrolidone (NMP) at a mass ratio of 97:2:1, and a positive electrode slurry was prepared after the mixture was fully stirred and uniformly mixed; the positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil, and then the positive electrode sheet was obtained after drying, cold pressing, and slitting. In the preparation of the positive electrode sheet, the composite material was used as the active material, and no other active material was added.

[0259] (2) Preparation of negative electrode sheet: the negative electrode active material artificial graphite, the conductive agent acetylene black, the binder styrene butadiene rubber (SBR), and the thickening agent carboxymethyl cellulose sodium (CMC-Na) were dissolved in deionized water at a mass ratio of 96:1.5:1.5:1.0, and a negative electrode slurry was prepared after the mixture was fully stirred and uniformly mixed; the negative electrode slurry was coated on the negative electrode current collector copper foil, and then the negative electrode sheet was obtained after drying, cold pressing, and slitting.

[0260] (3) Separation membrane: a polypropylene membrane was used.

[0261] (4) Preparation of electrolyte: ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1, and then LiPF6 was uniformly dissolved in the above solution to obtain the electrolyte. In the electrolyte, the concentration of LiPF6 was 1 mol / L.

[0262] (5) Preparation of lithium ion battery: the above positive electrode sheet, separator, and negative electrode sheet were stacked and wound in sequence to obtain an electrode assembly; the electrode assembly was placed in an outer package, and the electrolyte prepared above was added, and after processes such as packaging, standing, formation, and aging, a lithium ion battery was obtained.

[0263] In combination with Table 3, in Example 36 and Comparative Examples 7-9, lithium ion battery monomers were prepared using a composite material as a lithium supplement and lithium iron phosphate as a positive active material.

[0264] Table 3 Experimental parameters and results of Example 36 and Comparative Examples 7-9

[0265]

[0266] [Preparation of battery monomer]

[0267] (1) Preparation of positive electrode sheet: a composite material, positive active material lithium iron phosphate (LFP), binder polyvinylidene fluoride (PVDF), and conductive agent (acetylene black) were dissolved in solvent N-methyl pyrrolidone (NMP) in a mass ratio of 95:2:2:1, and after being fully stirred and mixed uniformly, a positive electrode slurry was prepared; the positive electrode slurry was uniformly coated on a positive current collector aluminum foil, and then dried, cold-pressed, and cut to obtain a positive electrode sheet. In the preparation of the positive electrode sheet, the composite material was used as a lithium supplement.

[0268] (2) Preparation of negative electrode sheet: negative active material artificial graphite, conductive agent acetylene black, binder styrene butadiene rubber (SBR), and thickening agent sodium carboxymethyl cellulose (CMC-Na) were dissolved in deionized water in a mass ratio of 96:1.5:1.5:1.0, and after being fully stirred and mixed uniformly, a negative electrode slurry was prepared; the negative electrode slurry was coated on a negative current collector copper foil, and then dried, cold-pressed, and cut to obtain a negative electrode sheet.

[0269] (3) Separator: polypropylene film was used.

[0270] (4) Preparation of electrolyte: ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1, and then LiPF6 was uniformly dissolved in the above solution to obtain the electrolyte. In the electrolyte, the concentration of LiPF6 was 1 mol / L.

[0271] (5) Preparation of the lithium ion battery: stack and roll the above positive electrode sheet, separator and negative electrode sheet in sequence to obtain an electrode assembly; place the electrode assembly into an outer package, add the electrolyte prepared above, and after processes such as packaging, standing, formation and aging, a lithium ion battery is obtained.

[0272] [Measurement of the first cycle charge capacity of the lithium ion battery]

[0273] The assembled lithium ion battery is charged at a rate of 0.1C to 4.25V, and then left to stand for 5 minutes. The first cycle charge capacity of the lithium ion battery at this time is recorded. The first cycle charge capacity of the lithium ion battery is obtained by dividing the first cycle charge capacity of the battery by the mass of the composite material.

[0274] [Measurement of the average volume particle size of the catalyst and lithium-containing compound]

[0275] The average volume particle size can be determined by a particle size analyzer-laser diffraction method. Specifically, the laser diffraction scattering particle size analyzer can be used to measure the average volume particle size according to the manufacturer's instructions, with reference to the standard GB / T 19077-2016. For example, before preparing the composite material, an appropriate amount of catalyst and lithium-containing compound is taken respectively, and the average volume particle size of the material is tested by using a MasterSizer 2000 laser particle size analyzer. For example, an appropriate amount of sample to be tested (the sample concentration is guaranteed to have an obscuration of 8-12%) is taken, 20 ml of deionized water is added, and the sample is dispersed for 5 minutes (53 KHz / 120 W) to ensure complete dispersion. Then, the sample is measured according to the standard GB / T 19077-2016 / ISO 13320:2009.

[0276] [Measurement of the powder resistivity of the composite material]

[0277] The powder of the composite material is dried, and an appropriate amount of powder is weighed. Then, the powder resistivity of the sample is measured by using a powder resistivity tester (ST2722 type digital four-probe instrument, Suzhou Jingge Electronics Co., Ltd.), according to GB / T 30835-2014, and the test pressure is 20 MPa.

[0278] [Measurement of the aspect ratio]

[0279] The aspect ratio of the carbon material is the same as that of the composite material, which can be measured by a transmission electron microscope. Normally, 20 well-dispersed composite materials are taken, their outer diameters and lengths are measured respectively, and the average value is taken as the aspect ratio of the carbon material.

[0280] [Measurement of the decomposition voltage]

[0281] The decomposition voltage of the lithium-containing compound is the average charging voltage during the first charging process, i.e., the ratio of the charging energy to the charging capacity.

[0282] [Measurement of resistance of electrode sheet]

[0283] After full charging, the positive electrode sheet is disassembled, and small round pieces with an area of 1540 mm 2 are cut from the left, middle and right of the electrode sheet. The indicator light of the electrode resistance meter (for example, the electrode resistance meter of Yuaneng Technology) is turned on, the small round pieces are placed in the appropriate position of the membrane resistance meter "probe", the "start" button is clicked, and the reading is taken when the reading is stable. Two positions of each small round piece are tested, and the average value of six measurements is calculated, which is the membrane resistance of the electrode sheet.

[0284] [Measurement of mass content of carbon material, mass content of catalyst, and mass content of lithium-containing compound in composite material]

[0285] The components of the composite material and the mass content of each component can be measured by the following method.

[0286] As an example, an appropriate amount of powder of the composite material is taken, and a scanning electron microscope is used for observation. Carbon materials with tubular structures can be observed. Next, an energy dispersive spectrometer is used to determine the elemental composition of the composite material. Then, a thermogravimetric analysis method is used to determine the material and mass content of each component.

[0287] As an example, an appropriate amount of powder of the composite material is taken, and the powder is dissolved in deionized water (or a corresponding dissolvable solvent). Since the lithium-containing compound can be dissolved in water, the lithium-containing compound can be separated from the composite material, and the weight of the lithium-containing compound is measured to calculate the mass content of the lithium-containing compound. Then, the undissolved substances in the powder are added to another solvent that can dissolve the catalyst, and the weight of the catalyst is measured to calculate the mass content of the catalyst. Finally, only carbon materials are obtained, and the mass content of the carbon materials can be calculated by weighing.

[0288] It should be noted that the first cycle charge capacity, average volume particle size, resistivity, aspect ratio, decomposition voltage, resistance, mass content of carbon material in composite material, mass content of catalyst, and mass content of lithium-containing compound in the embodiments of the present application are well-known in the art, have the meanings known in the art, and can be measured by the test methods and instruments known in the art.

[0289] As shown in Examples 1-24 and Comparative Example 1, and as shown in Examples 25-27 and Comparative Examples 4-6, compared with only adding a lithium-containing compound, the composite material of the embodiments of the present application can improve the capacity of the battery cell.

[0290] As shown in Embodiments 1-5, the mass content of the carbon material is set to 1wt%-40wt%, and the battery cell has a higher capacity; the mass content of the carbon material is set to 2wt%-25wt%, and the composite material has a lower powder resistivity, and the battery cell has a higher capacity.

[0291] As shown in Embodiments 6-9, the mass content of the catalyst is set to 0.1wt%-20wt%, and the battery cell has a higher capacity; the mass content of the catalyst is set to 0.5wt%-10wt%, and the lithium-containing compound has a lower decomposition voltage, and the battery cell has a higher capacity.

[0292] As shown in Embodiments 10-13, the aspect ratio of the carbon material is set to 100:1-3000:1, and the battery cell has a higher capacity; the aspect ratio of the carbon material is set to 200:1-2000:1, and the risk of agglomeration of the carbon material is reduced, and the battery cell has a higher capacity.

[0293] As shown in Embodiments 14-17, the mass ratio of the polymer to DMF is set to 1:1-1:20, and the battery cell has a higher capacity; the mass ratio of the polymer to DMF is set to 1:2-1:15, and the battery cell has a higher capacity.

[0294] As shown in Embodiments 18-21, the calcination temperature is set to 300℃-480℃, and the battery cell has a higher capacity; the calcination temperature is set to 350℃-450℃, and the carbonization effect of the polymer material is better, and a carbon material with better crystallinity can be obtained, and decomposition of the lithium-containing compound at high temperature can also be avoided, and the battery cell has a higher capacity.

[0295] As shown in Embodiments 22-24, the catalyst and the lithium-containing compound have a smaller particle size, which is beneficial to improve the catalytic effect of the catalyst and reduce the decomposition voltage of the lithium-containing compound; in the case that the particle size of the catalyst and the lithium-containing compound is larger, the catalytic effect of the catalyst is weakened, the decomposition voltage of the lithium-containing compound is reduced less, and the capacity of the battery cell is improved less.

[0296] As shown in Embodiments 25-27, the embodiments of the present application are suitable for a variety of different lithium-containing compounds; as shown in Embodiments 28-29 and Embodiments 34-35, the embodiments of the present application are suitable for a variety of different catalysts.

[0297] In combination with the embodiment 30, the mass content of the carbon material is low, and the composite material has a high powder resistivity; the mass content of the catalyst is low, and the decomposition voltage of the lithium-containing compound is high; the aspect ratio of the carbon material is small, and the capacity of the battery cell is not obviously improved; in combination with the above, the battery cell of this embodiment has a low capacity. In combination with the embodiment 31, although the carbon material has a high mass ratio, the mass ratio of the polymer and DMF is large, the content of DMF is low, and it is difficult to obtain a composite material with a good tubular structure by electrospinning, the composite effect of the lithium-containing compound and the carbon material is poor, the resistivity of the composite material is large, and the battery cell has a low capacity. In combination with the embodiment 32, the mass content of the catalyst is large, and thus the mass content of the lithium-containing compound is low; in addition, the calcination temperature is high, part of the carbon material and the lithium-containing compound are thermally decomposed to cause the destruction of the tubular structure, the resistivity of the composite material is increased, and the battery cell has a low capacity; in combination with the embodiment 33, the aspect ratio of the carbon material is large, and the agglomeration of the carbon material causes the increase of the resistivity of the powder of the composite material, and the battery cell has a low capacity.

[0298] In combination with the comparative example 2, only the lithium-containing compound and the catalyst are mixed, the mixed material has a high resistivity, and the adverse effects of the vacancies generated after the decomposition of the lithium-containing compound cannot be solved, and the capacity of the battery cell is low.

[0299] In combination with the comparative example 3, only the lithium-containing compound is coated with carbon, the decomposition voltage of the lithium-containing compound is high, which is not conducive to improving the capacity of the battery cell. Although in the comparative example 3, only the lithium-containing compound is coated with carbon, the resistivity of the powder and the resistivity of the film are low, but because the decomposition voltage of the lithium-containing compound is high, it is difficult to be normally used.

[0300] In combination with the embodiment 36 and the comparative examples 7-9, the composite material and the lithium iron phosphate positive active material are mixed, and the battery cell prepared has a high capacity.

[0301] Although only lithium iron phosphate is used as the positive active material in the embodiments, the composite material of the present application is also applicable to battery cells of other active materials. Similarly, although only the oxide of the transition metal is used as the catalyst in the embodiments, other catalysts that can be used to catalyze the decomposition of the lithium-containing compound, such as the carbide of the transition metal, the nitride of the transition metal, etc., can also be applicable to the embodiments of the present application.

[0302] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration, function, and effect as the technical idea of the present application are included in the technical scope of the present application. Furthermore, other modes constructed by applying various modifications to the embodiments, or by combining part of the configurations of the embodiments, which can be conceived by those skilled in the art, without departing from the spirit of the present application, are also included in the scope of the present application.

Claims

1. A composite material, characterized by, The composite material comprises: a lithium-containing compound, a catalyst, and a carbon material, wherein the carbon material has a hollow tubular structure, and the lithium-containing compound and the catalyst are arranged in the tubular structure; the lithium-containing compound comprises lithium, carbon, and oxygen; the catalyst comprises at least one of an oxide of a transition metal, a carbide of a transition metal, or a nitride of a transition metal.

2. The composite material of claim 1, wherein, The lithium-containing compound and the catalyst are arranged on an inner wall of the tubular structure.

3. The composite material according to claim 1 or 2, characterized in that, At least part of the catalyst is located on a surface of the lithium-containing compound.

4. The composite material according to any one of claims 1 to 3, characterized in that, The chemical formula of the lithium-containing compound is Li2C x O y wherein 1≤x≤4, 3≤y≤6.

5. The composite material of claim 4, wherein, The lithium-containing compound comprises at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5, or Li2C4O6.

6. The composite material according to any one of claims 1 to 5, wherein, The chemical formula of the oxide of the transition metal is M α O β wherein 0 < a ≤ 3, 0 < β ≤ 5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu, or Ti.

7. The composite material of claim 6, wherein, M α O β comprises at least one of NiO, Co3O4, Fe2O3, MoO3, or V2O5.

8. The composite material of any one of claims 1-7, wherein, The carbide of the transition metal comprises at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide, or nickel carbide; and / or, the nitride of the transition metal comprises at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride, or nickel nitride.

9. The composite material of any one of claims 1-8, wherein, A mass content A of the carbon material satisfies 1wt%≤A≤40wt% based on a total mass of the composite material.

10. The composite material of claim 9, wherein, A satisfies 2wt%≤A≤25wt%.

11. The composite material of any one of claims 1-10, wherein, A mass content B of the catalyst satisfies 0.1wt%≤B≤20wt% based on a total mass of the composite material.

12. The composite material of claim 11, wherein, B satisfies 0.5wt%≤B≤10wt%.

13. The composite material of any one of claims 1-12, wherein, A mass content C of the lithium-containing compound satisfies 45wt%≤B≤98.9wt% based on a total mass of the composite material.

14. The composite material of claim 13, wherein, C satisfies 70wt%≤B≤85wt%.

15. The composite material of any one of claims 1-13, wherein, An aspect ratio E of the carbon material satisfies 100:1≤E≤3000:

1.

16. The composite material of claim 15, wherein, E satisfies 200:1≤E≤2000:

1.

17. The composite material of any one of claims 1-16, wherein, In the composite material, a decomposition voltage V1 of the lithium-containing compound satisfies V1<4.8V.

18. The composite material of claim 17, wherein, V1 satisfies V1<4.4V.

19. The composite material of any one of claims 1-18, wherein, A resistivity P of the composite material satisfies 0.2Ω·cm<P<101Ω·cm.

20. The composite material of claim 19, wherein, P satisfies 0.2Ω·cm<P<5.5Ω·cm.

21. The composite material of any one of claims 1-20, wherein, the average volume particle size Dv of the lithium-containing compound 1 50 greater than the average volume particle size Dv of the catalyst 2 50.

22. The composite material of claim 21, wherein, The average volume particle diameter Dv of the lithium-containing compound 1 50 satisfies: 100 nm ≤ Dv 1 50 ≤ 1000 nm, the average volume particle diameter Dv of the catalyst 2 50 satisfies: 50 nm ≤ Dv 2 50 ≤ 500 nm.

23. A method of making the composite material of any one of claims 1-22, characterized in that, The composite material comprises: mixing a lithium-containing compound and a catalyst to obtain a mixed material of the lithium-containing compound and the catalyst, wherein the catalyst comprises at least one of an oxide of a transition metal, a carbide of a transition metal, or a nitride of a transition metal, and the lithium-containing compound comprises lithium, carbon, and oxygen; adding the mixed material of the lithium-containing compound and the catalyst to a slurry containing a polymer material to obtain an electrospinning stock solution; electrospinning the electrospinning stock solution to obtain a precursor; calcining the precursor in an inert atmosphere to obtain the composite material.

24. The method of claim 23, wherein, The chemical formula of the lithium-containing compound is Li2C x O y wherein 1≤x≤4, 3≤y≤6.

25. The method of claim 24, wherein, The lithium-containing compound comprises at least one of Li2C2O4, Li2CO3, Li2C4O4, Li2C3O5, or Li2C4O6.

26. The method of any one of claims 23-25, wherein, The chemical formula of the oxide of the transition metal is M α O β wherein 0 < a ≤ 3, 0 < β ≤ 5, and M includes at least one of Ni, Co, Fe, Mn, V, Cr, Cu, or Ti.

27. The method of claim 26, wherein, M α O β comprises at least one of NiO, Co3O4, Fe2O3, MoO3, or V2O5.

28. The method of any one of claims 23-27, wherein, The carbide of the transition metal comprises at least one of molybdenum carbide, vanadium carbide, tungsten carbide, titanium carbide, cobalt carbide, iron carbide, or nickel carbide; and / or, the nitride of the transition metal comprises at least one of molybdenum nitride, vanadium nitride, titanium nitride, manganese nitride, cobalt nitride, iron nitride, or nickel nitride.

29. The method of any one of claims 23-27, wherein, The solute in the slurry containing the polymer material includes the polymer material, and the solvent in the slurry containing the polymer material is an organic solvent.

30. The method of claim 29, wherein, The organic solvent includes N, N-dimethylformamide.

31. The method of claim 29 or 30, wherein, The polymer material includes at least one of polyvinylpyrrolidone, polyacrylonitrile, or polyethylene oxide.

32. The method of claim 31, wherein, The polymer material includes polyacrylonitrile.

33. The method of claim 30, wherein, The mass ratio D of the polymer material to the N, N-dimethylformamide satisfies 1:20≤D≤1:

1.

34. The method of claim 33, wherein, D satisfies 1:15≤D≤1:

2.

35. The method of any one of claims 23-34, wherein, The temperature T of the calcination satisfies 300℃≤T≤480℃.

36. The method of claim 35, wherein, T satisfies 350℃≤T≤450℃.

37. The method of any one of claims 23-36, wherein, The mixing of the lithium-containing compound and the catalyst to obtain a mixed material of the lithium-containing compound and the catalyst includes: The mixing of the lithium-containing compound and the catalyst and high-energy ball milling to obtain the mixed material of the lithium-containing compound and the catalyst.

38. The method of claim 37, wherein, The ball-to-material ratio F of the high-energy ball milling satisfies 10:1≤F≤15:1; and / or, the revolution speed R1 of the high-energy ball milling satisfies 1000r / min≤R1≤1500r / min; and / or, the rotation speed R2 of the high-energy ball milling satisfies 2500r / min≤R2≤3000r / min.

39. The method of any one of claims 23-38, wherein, The mass ratio C of the lithium-containing compound to the catalyst satisfies 15:1≤C≤40:

1.

40. The method of any one of claims 23-39, wherein, the average volume particle size Dv of the lithium-containing compound 1 50 greater than the average volume particle size Dv of the catalyst 2 50.

41. The method of claim 40, wherein, The average volume particle diameter Dv of the lithium-containing compound 1 50 satisfies: 100 nm ≤ Dv 1 50 ≤ 1000 nm, the average volume particle diameter Dv of the catalyst 2 50 satisfies: 50 nm ≤ Dv 2 50 ≤ 500 nm.

42. A positive electrode sheet characterized by comprising: including: a positive electrode active material; the composite material of any one of claims 1-22, and / or the composite material prepared by the method of any one of claims 23-41.

43. The cathode sheet of claim 42, wherein, The resistance R of the positive electrode tab satisfies 0.3Ω 44. A battery cell, characterized by including the positive electrode tab of claim 42 or 43.

45. A battery, comprising: including the battery cell of claim 44.

46. An electrical device, comprising: including the battery of claim 45.

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