Negative electrode material and battery

Abstract

A negative electrode material, a preparation method therefor and a battery. The negative electrode material comprises a carbon matrix and an active substance, the carbon matrix containing an oxygen element and a nitrogen element. The mass content of the oxygen element in the negative electrode material is A%, the mass content of the nitrogen element in the negative electrode material is B%, and the powder electrical conductivity of the negative electrode material is P S / cm, A, B and P satisfying the following relationship: (I), M≤5. As the relationship between the nitrogen content, the oxygen content and the powder electrical conductivity satisfies (I), M≤5, while the powder electrical conductivity of the negative electrode material is increased, the initial coulombic efficiency of the negative electrode material is improved.

Description

Anode materials and batteries

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed on March 15, 2024, with application number 202410297451.X and titled “Negative electrode material, preparation method thereof, and battery”. Technical Field

[0003] The present application relates to the technical field of negative electrode materials, and in particular to negative electrode materials and batteries. Background Art

[0004] Anode materials are key to achieving high capacity and long cycle life in lithium-ion batteries. Traditional graphite anode materials often have low capacity, while silicon-based anode materials have become increasingly popular worldwide due to their high capacity. However, silicon anodes experience volume expansion exceeding 300% during lithium insertion. Furthermore, silicon's poor electrical conductivity leads to high internal resistance, which significantly hinders further expansion of its application.

[0005] Porous carbon materials have a rich pore structure, which can provide a large amount of embedding space for nano-silicon materials, inhibit the expansion effect of silicon negative electrode materials, and improve their pulverization problem; at the same time, the carbon skeleton of porous carbon has good electronic conductivity, which can provide a developed conductive network for silicon negative electrode materials, improve their conductivity, and enhance their first coulombic efficiency. Therefore, there has been a boom in the development of silicon-carbon negative electrodes in the field of negative electrode materials. However, the developed silicon-carbon negative electrodes often have certain oxygen and nitrogen impurities, which may have a significant impact on the performance of silicon-carbon negative electrode materials, and currently research on this impact is extremely scarce.

[0006] Summary of the Invention

[0007] The present application provides a negative electrode material and a battery, wherein the relationship between the nitrogen and oxygen content of the negative electrode material and the powder conductivity satisfies M≤5, which makes the negative electrode material have both high first coulombic efficiency and excellent cycle capacity retention rate.

[0008] In a first aspect, the present application provides a negative electrode material, wherein the negative electrode material includes a carbon matrix and an active material, and the negative electrode material contains oxygen and nitrogen elements.

[0009] The mass content of oxygen in the negative electrode material is A%, the mass content of nitrogen in the negative electrode material is B%, the powder conductivity of the negative electrode material is PS / cm, and A, B and P satisfy the following relationship:

[0010] M≤5.

[0011] In some embodiments, the mass content of oxygen in the negative electrode material is 0.2% to 2%.

[0012] In some embodiments, the mass content of nitrogen in the negative electrode material is 0.2% to 2%.

[0013] In some embodiments, the powder conductivity of the negative electrode material is 0.3 S / cm to 10 S / cm.

[0014] In some embodiments, the volume median particle size D of the negative electrode material is 50 8μm~20μm.

[0015] In some embodiments, the specific surface area of ​​the negative electrode material is ≤100m 2 / g.

[0016] In some embodiments, the compacted density of the negative electrode material is 0.8 g / cm 3 ~1.2g / cm 3 .

[0017] In some embodiments, the total pore volume of the negative electrode material is 0.001 cm 3 / g~0.1cm 3 / g.

[0018] In some embodiments, the mass content of carbon in the negative electrode material is 40% to 60%.

[0019] In some embodiments, the mass content of silicon in the negative electrode material is 35% to 55%.

[0020] In some embodiments, the average pore size of the pores in the negative electrode material is 0.5 nm to 20 nm.

[0021] In some embodiments, the carbon matrix includes at least one of amorphous carbon, graphitized carbon, mesocarbon microbeads, and carbon gel.

[0022] In some embodiments, the carbon matrix includes at least one of amorphous carbon, graphitized carbon, mesocarbon microbeads, and carbon gel, wherein the amorphous carbon includes at least one of hard carbon, soft carbon, and activated carbon.

[0023] In some embodiments, the carbon matrix includes at least one of amorphous carbon, graphitized carbon, mesocarbon microbeads, and carbon gel, wherein the graphitized carbon includes at least one of graphite and graphitized carbon nanotubes.

[0024] In some embodiments, the carbon matrix has pores, and the active material is at least partially distributed in the pores of the carbon matrix.

[0025] In some embodiments, the carbon matrix has pores, the pores include micropores, and the volume of the micropores accounts for ≥80% of all pores.

[0026] In some embodiments, the carbon matrix has pores, and the volume of pores with a pore diameter ranging from 2 nm to 5 nm accounts for 0% to 10% of all pores.

[0027] In some embodiments, the carbon matrix has pores, and the total pore volume of the carbon matrix is ​​0.2 cm 3 / g~2cm 3 / g.

[0028] In some embodiments, the active material includes a silicon-based active material, and the silicon-based active material includes at least one of crystalline silicon, amorphous silicon, and composite particles of crystalline and amorphous silicon.

[0029] In some embodiments, the active material includes a silicon-based active material, and the active material further includes at least one of Sn, P, S, Ge, and Pb.

[0030] In some embodiments, the morphology of the active material includes at least one of a dot shape, a sphere shape, an ellipsoid shape, and a flake shape.

[0031] In some embodiments, the surface of the negative electrode material has a coating layer, and the material of the coating layer includes at least one of metal oxide, carbon material, conductive polymer, fluoride, phosphate and nitride.

[0032] In some embodiments, the metal oxide includes at least one of oxides of Sn, Ge, Fe, Si, Cu, Ti, Na, Mg, Al, Ca, and Zn.

[0033] In some embodiments, the conductive polymer includes at least one of polyaniline, polyacetylene, polypyrrole, polythiophene, poly-3-hexylthiophene, poly(p-phenylene vinylene), polypyridine, and polystyrene vinylene.

[0034] In some embodiments, the fluoride includes at least one of polyvinyl fluoride, fluoropolymer, sodium fluoride, potassium fluoride, fluorocarbon polymer, fluorosilicone polymer, hexafluorobutyl acrylate, polytetrafluoroethylene, fluorinated ethylene-propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride and polyvinyl fluoride.

[0035] In some embodiments, the phosphate includes at least one of magnesium phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, chromium phosphate, cobalt phosphate, nickel phosphate, germanium phosphate, zirconium phosphate, niobium phosphate, molybdenum phosphate, tantalum phosphate, tungsten phosphate, and lanthanum phosphate.

[0036] In some embodiments, the nitride includes at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

[0037] In some embodiments, the carbon material includes at least one of amorphous carbon and graphitized carbon.

[0038] In some embodiments, the coating layer has a thickness of 1 nm to 300 nm.

[0039] In some embodiments, the coating layer accounts for ≤10% by mass of the negative electrode material.

[0040] In a second aspect, the present application provides a battery, comprising the negative electrode material described in any one of the first aspects.

[0041] By adopting the above technical solution, this application has at least the following beneficial effects:

[0042] The negative electrode material provided by the present application comprises a carbon matrix and an active substance. The carbon matrix contains oxygen and nitrogen elements. The applicant has found through a large number of experiments that the relationship between the mass content A% of the oxygen element, the mass content B% of the nitrogen element and the powder conductivity P of the negative electrode material satisfies M≤5 can make the negative electrode material have both high first coulombic efficiency and excellent cycle capacity retention rate.

[0043] The lone pairs of electrons on the p orbitals of nitrogen atoms and oxygen atoms in the negative electrode material can participate in the π-π conjugated system of the carbon matrix to form a larger p-π conjugated system, increasing the number of mobile electrons in the carbon matrix, thereby increasing the powder conductivity of the negative electrode material. High powder conductivity allows the negative electrode material to transport lithium ions more efficiently, so that during the first charge and discharge process, more lithium ions can participate in the reversible charge and discharge reaction, reducing irreversible capacity loss, thereby improving the first coulombic efficiency of the negative electrode material. The applicant has found through a large number of experiments that when M>5, excessive nitrogen and oxygen doping, the tetrahedral structure formed by the S and P electron orbitals of nitrogen and oxygen atoms will cause the carbon atoms in the carbon matrix to deviate from the π-π conjugated plane, resulting in a reduction in the number of π-π conjugated carbon atoms, and the COOC, CNNC and other groups formed by nitrogen, oxygen atoms and carbon atoms will split the π-π conjugated system, further reducing the electronic conductivity of the negative electrode material. The decrease in the conductivity of the negative electrode material will cause the battery to form more solid electrolytes during the cycle, resulting in irreversible consumption of active lithium ions, that is, the number of lithium ions that can participate in deintercalation is reduced, resulting in a decrease in the first coulombic efficiency of the battery. Therefore, when the relationship between the mass content A% of the oxygen element, the mass content B% of the nitrogen element and the powder conductivity P in the negative electrode material is controlled by the present application to meet the above relationship, the effect of nitrogen and oxygen doping on the first coulombic efficiency of the negative electrode material can be reduced, so that the negative electrode material has both high first coulombic efficiency and excellent cycle capacity retention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a schematic structural diagram of a π-π conjugated system of a carbon matrix of a negative electrode material provided in an embodiment of the present application;

[0045] FIG2 is a schematic structural diagram of the p-π conjugated system of the carbon matrix of the negative electrode material provided in an embodiment of the present application;

[0046] FIG3 is a schematic structural diagram of a p-π conjugated system of a carbon matrix when excessive nitrogen and oxygen elements are doped in the negative electrode material provided in an embodiment of the present application;

[0047] FIG4 is a flow chart of a method for preparing a negative electrode material provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The following is a preferred implementation of the embodiments of the present application. It should be noted that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the embodiments of the present application. These improvements and modifications are also considered to be within the scope of protection of the embodiments of the present application.

[0049] In a first aspect, the present application provides a negative electrode material, the negative electrode material comprising a carbon matrix and an active material, the negative electrode material further comprising oxygen and nitrogen elements;

[0050] The mass content of oxygen in the negative electrode material is A%, the mass content of nitrogen in the negative electrode material is B%, and the powder conductivity of the negative electrode material is PS / cm, and A, B and P satisfy the following relationship:

[0051] M≤5.

[0052] In the above scheme, the negative electrode material includes a carbon matrix and an active material. The negative electrode material contains oxygen and nitrogen elements. As shown in Figures 1 and 2, the lone pairs of electrons on the p orbitals of nitrogen atoms and oxygen atoms can participate in the π-π conjugated system of the carbon matrix to form a larger p-π conjugated system, increasing the number of mobile electrons in the carbon matrix, thereby increasing the powder conductivity of the negative electrode material. High powder conductivity allows the negative electrode material to more efficiently transport lithium ions, so that during the first charge and discharge process, more lithium ions can participate in the reversible charge and discharge reaction, reducing irreversible capacity loss, thereby improving the first coulombic efficiency of the battery prepared from the negative electrode material. At the same time, the present application controls the relationship between the mass content A% of the oxygen element, the mass content B% of the nitrogen element and the powder conductivity P of the negative electrode material to satisfy M≤5. The applicant has found through a large number of experiments that when M>5, as shown in Figure 3, excessive nitrogen and oxygen doping, the tetrahedral structure formed by the S and P electron orbitals of nitrogen and oxygen atoms will cause the carbon atoms in the carbon matrix to deviate from the π-π conjugated plane, resulting in a reduction in the number of π-π conjugated carbon atoms, and the COOC, CNNC and other groups formed by nitrogen, oxygen atoms and carbon atoms will split the π-π conjugated system, further reducing the electronic conductivity of the negative electrode material. The decrease in the conductivity of the negative electrode material will cause the battery prepared from the negative electrode material to form more solid electrolytes during the cycle, resulting in irreversible consumption of active lithium ions, that is, the number of lithium ions that can participate in deintercalation is reduced, resulting in a decrease in the first coulombic efficiency of the battery prepared from the negative electrode material. Therefore, when the relationship between the mass content A% of the oxygen element, the mass content B% of the nitrogen element and the powder conductivity P in the negative electrode material is controlled by the present application to meet the above relationship, the effect of nitrogen and oxygen doping on the first coulombic efficiency of the negative electrode material can be reduced, so that the negative electrode material has both a higher first coulombic efficiency and an excellent cycle capacity retention rate.

[0053] In some embodiments, the mass content of oxygen is 0.2% to 2%, i.e., the A value is 0.2 to 2. Optionally, the mass content of oxygen can be 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, etc., or other values ​​within the range. The mass content of oxygen can be selected based on actual needs and is not limited here. It is understood that an oxygen mass content A% within the above range can improve the electrical conductivity of the carbon matrix powder. The oxygen may exist in at least one of OC, O-Si, and OH.

[0054] In some embodiments, the mass content of nitrogen is 0.2% to 2%, that is, the B value is 0.2 to 2. Optionally, the mass content of nitrogen can be 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% and 2%, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here. It can be understood that the mass content B% of nitrogen is within the above range. While improving the powder conductivity of the carbon matrix, it reduces the breakage of the π-π conjugated system of the carbon matrix caused by nitrogen doping. The nitrogen element may exist in the form of at least one of Si-N, CN, and NH.

[0055] In some embodiments, an appropriate amount of sample is pressed into a pellet and then attached to a sample plate. The sample is placed in the sample chamber of a Thermo Scientific K-Alpha XPS instrument. When the pressure in the sample chamber is better than 5x10-7 mbar, the sample is sent into the analysis chamber. The spot size is 400 μm, the operating voltage is 12 kV, and the filament current is 6 mA. The full spectrum scan energy is 150 eV with a step size of 1 eV; the narrow spectrum scan energy is 50 eV with a step size of 0.1 eV. The X-ray energy spectrum of the sample is scanned, and the energy spectrum is corrected and peak-separated to obtain the corresponding chemical bond information.

[0056] In some embodiments, the powder conductivity of the negative electrode material is 0.3S / cm to 10S / cm, that is, the P value is 0.3 to 10. Optionally, the powder conductivity of the negative electrode material can be specifically 0.3S / cm, 2S / cm, 4S / cm, 6S / cm, 8S / cm and 10S / cm, etc., or other values ​​within the range, which can be selected according to actual needs and are not limited here. It can be understood that the powder conductivity P of the negative electrode material within the above range can allow the negative electrode material to more efficiently transport lithium ions, so that during the first charge and discharge process of the battery prepared by the negative electrode material, more lithium ions can participate in the reversible charge and discharge reaction of the battery prepared by the negative electrode material, reducing the irreversible capacity loss of the battery, thereby improving the first coulombic efficiency of the negative electrode material.

[0057] In some embodiments, the volume median particle size D of the negative electrode material is 50 The particle size of the negative electrode material is 8μm to 20μm, and specifically can be 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm and 20μm, etc. Of course, other values ​​within the above range are also possible and are not limited here. When the particle size of the negative electrode material is within the above range, the diffusion path of the lithium ion is short, which can ensure the time for lithium ion insertion and extraction, so that the negative electrode material can achieve a state of rapid and sufficient lithium insertion, thereby ensuring the charge and discharge performance of the battery.

[0058] In some embodiments, the specific surface area of ​​the negative electrode material is ≤ 100 m 2 / g, specifically 100m 2 / g、90m 2 / g、80m 2 / g、70m 2 / g, 60m 2 / g, 50m 2 / g, 40m 2 / g、30m 2 / g, 20m 2 / g and 10m 2 / g, etc., and of course other values ​​within the above range are also possible and are not limited here. It is understood that the specific surface area of ​​the negative electrode material will affect the contact area between the negative electrode material and the electrolyte. The specific surface area of ​​the negative electrode material within the above range can reduce the amount of lithium ions consumed by the SEI film formed during the initial charge and discharge process of the battery, thereby reducing the irreversible capacity loss of the battery.

[0059] In some embodiments, the compacted density of the negative electrode material is 0.8 g / cm 3 ~1.2g / cm 3 , specifically 0.8g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 , 1.1g / cm 3 and 1.2 g / cm 3 Of course, it can also be other values ​​within the above range, which is not limited here.

[0060] In some embodiments, the carbon matrix of the negative electrode material includes at least one of amorphous carbon, graphitized carbon, mesophase carbon microbeads, and carbon gel, wherein the amorphous carbon includes at least one of hard carbon, soft carbon, and activated carbon, and at least one of mesophase carbon microbeads and carbon gel, wherein the graphitized carbon includes at least one of graphite and graphitized carbon nanotubes. The type of carbon matrix can be selected according to actual needs and is not limited here. It is understood that the carbon matrix selected from the above materials can all play the role of supporting the skeleton and also have good electrical conductivity to ensure the powder conductivity of the negative electrode material.

[0061] In some embodiments, the pores of the carbon matrix include micropores. It is understandable that the pores of the carbon matrix can provide embedding space and expansion space for nano-silicon, thereby alleviating the expansion effect of the above-mentioned negative electrode material.

[0062] In some embodiments, the pores in the carbon matrix include micropores, and the volume proportion of the micropores in all pores is ≥80%. Specifically, the volume proportion of the micropores in all pores can be 80%, 81%, 82%, 83%, 84%, 85%, 87%, 88%, 90%, 92%, 93%, 95%, 98% or 99%, etc., which is not limited here.

[0063] In some embodiments, the volume proportion of pores in the carbon matrix with a pore diameter in the range of 2nm to 5nm in all pores can be 0%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., which is not limited here. It can be understood that the pores of the carbon matrix are mainly micropores, and the pore size distribution within this range is conducive to the deposition of silicon material during the deposition process, thereby improving the density of the negative electrode material. In some embodiments, taking the active material as silicon material as an example, under stirring, 150mL of 20% mass fraction HF acid solution is added dropwise to 10g of negative electrode material, SiF4 and H2 gas is generated, and heat is released. After no gas is generated, the supernatant acid solution is removed by centrifugation, and 150mL of 20% mass fraction HF acid solution is added to the negative electrode material again. After stirring for 12h, the supernatant acid solution is removed again by centrifugation, and then the negative electrode material is washed with pure water until neutral and dried to obtain the negative electrode material after removing the silicon material, that is, the carbon matrix.

[0064] In some embodiments, the pores in the negative electrode material include micropores, wherein the volume of the micropores in all pores accounts for ≤5%.

[0065] In some embodiments, the pores in the negative electrode material include mesopores, and the volume proportion of the mesopores in all pores is 87% to 97%.

[0066] In some embodiments, the pores in the negative electrode material include macropores, and the volume of the macropores accounts for ≤13% of the total pore volume. It is understandable that because the active material, such as silicon particles, fills a large number of pores, particularly micropores, in the carbon material, the pores of the negative electrode material are primarily mesopores and macropores.

[0067] In some embodiments, the total pore volume of the negative electrode material is 0.001 cm 3 / g~0.1cm 3 / g; the total pore volume of the negative electrode material can be specifically 0.001cm 3 / g, 0.002cm 3 / g, 0.005cm 3 / g, 0.008cm 3 / g, 0.01cm 3 / g, 0.02cm 3 / g, 0.03cm 3 / g, 0.04cm 3 / g, 0.05cm 3 / g, 0.06cm 3 / g, 0.07cm 3 / g, 0.08cm 3 / g, 0.09cm 3 / g or 0.1cm 3 / g, etc., and of course, it can also be other values ​​within the above range, which is not limited here.

[0068] In some embodiments, the total pore volume of the carbon matrix is ​​0.2 cm 3 / g~2cm 3 / g; the total pore volume of the carbon matrix can be specifically 0.2cm 3 / g, 0.3cm 3 / g, 0.4cm 3 / g, 0.5cm 3 / g, 0.6cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.2cm 3 / g, 1.5cm 3 / g, 1.8cm 3 / g, 1.9cm 3 / g, 1.95cm 3 / g or 2cm 3 / g, etc., of course, it can also be other values ​​within the above range, which is not limited here. Compared with the negative electrode material after removing the active substance such as silicon particles, the pore volume of the negative electrode material containing active substances such as silicon particles is significantly reduced, indicating that the density of the negative electrode material is increased, and the specific capacity of the negative electrode material can be effectively improved. The present application controls the total pore volume of the negative electrode material filled with active substances such as silicon particles and the negative electrode material without active substances such as silicon particles within the above range, which can not only improve the specific capacity of the negative electrode material, but also ensure that the negative electrode material can reserve an appropriate amount of pores to alleviate the volume expansion caused by the process of active substances such as silicon particles and lithium insertion and extraction, which is beneficial to improving the cycle performance of the negative electrode material.

[0069] In some embodiments, the average pore size of the pores in the negative electrode material is 0.5 nm to 20 nm. Specifically, the average pore size of the pores in the negative electrode material can be 0.5 nm, 0.8 nm, 1.0 nm, 1.3 nm, 1.5 nm, 1.8 nm, 2.0 nm, 3.0 nm, 4.0 nm, 5.0 nm, 6.0 nm, 7.0 nm, 10 nm, 12 nm, 15 nm, 18 nm, or 20 nm, etc., without limitation herein. Controlling the average pore size of the pores in the negative electrode material not only improves the rate performance of the negative electrode material, but also helps to buffer the volume expansion of the active material and improve the structural stability of the negative electrode material.

[0070] In some embodiments, the mass content of carbon element in the negative electrode material is 40% to 60%, specifically 40%, 42%, 43%, 45%, 48%, 50%, 52%, 55%, 57%, 59% or 60%, etc., which is not limited here.

[0071] In some embodiments, the mass content of silicon in the negative electrode material is 35% to 55%, specifically 35%, 38%, 40%, 43%, 45%, 48%, 50%, 52% or 55%, etc., which is not limited here.

[0072] In some embodiments, the active material includes a silicon-based active material, and the silicon-based active material includes at least one of crystalline silicon, amorphous silicon, and crystalline and amorphous silicon composite particles. The type of active material can be selected according to actual needs and is not limited here. It can be understood that the active material is silicon particles, and the alloying mechanism of silicon gives it the advantage of high capacity, and the capacity of the prepared negative electrode material is higher.

[0073] In some embodiments, the active material further includes at least one of Sn, P, S, Ge, and Pb. The type of active material can be selected according to actual needs and is not limited here.

[0074] In some embodiments, the morphology of the active material includes at least one of a dot-like shape, a sphere, an ellipsoidal shape, and a flake-like shape. The morphology of the active material can be selected according to actual needs and is not limited here.

[0075] In some embodiments, the surface of the negative electrode material has a coating layer, and the material of the coating layer includes at least one of a metal oxide, a carbon material, amorphous silicon, a conductive polymer, a fluoride, a phosphate, and a nitride. It is understood that the coating layer located on the outermost layer of the negative electrode material has good electrical conductivity, which can significantly improve the electrical contact between the active material and the current collector, accelerate the transmission speed of electrons, and thus enhance the charge and discharge performance of the battery. At the same time, the coating layer can reduce direct contact between the active material and the electrolyte, reducing the occurrence of side reactions between the negative electrode material and the electrolyte, thereby improving the initial coulombic efficiency and cycle stability of the battery prepared with the negative electrode material.

[0076] In some embodiments, the metal oxide includes at least one of oxides of Sn, Ge, Fe, Si, Cu, Ti, Na, Mg, Al, Ca, and Zn.

[0077] In some embodiments, the carbon material includes at least one of amorphous carbon and graphitized carbon.

[0078] In some embodiments, the conductive polymer includes at least one of polyaniline, polyacetylene, polypyrrole, polythiophene, poly-3-hexylthiophene, poly(p-phenylene vinylene), polypyridine, and polystyrene vinylene.

[0079] In some embodiments, the fluoride includes at least one of vinyl fluoride, fluoropolymer, lithium fluoride, sodium fluoride, potassium fluoride, fluorocarbon polymer, fluorosilicone polymer, hexafluorobutyl acrylate, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), perfluoroalkoxy resin (PFA), polychlorotrifluoroethylene (PCTFE), ethylene monochlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF) and polyvinyl fluoride.

[0080] In some embodiments, the phosphate includes at least one of magnesium phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, chromium phosphate, cobalt phosphate, nickel phosphate, germanium phosphate, zirconium phosphate, niobium phosphate, molybdenum phosphate, tantalum phosphate, tungsten phosphate, and lanthanum phosphate.

[0081] In some embodiments, the nitride includes at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

[0082] In actual application, the material of the coating layer can be selected according to actual needs, and is not limited here. The coating layer can be a single-layer coating layer formed by the above-mentioned single material, or a coating layer formed by a combination of the above-mentioned multiple materials, or a multi-layer coating layer formed by a single material, or a multi-layer coating layer formed by multiple materials, etc. For example, it can be carbon coating followed by polymer coating, or carbon coating followed by polymer coating, or polymer coating followed by oxide coating, etc. The layer structure of the coating layer can be selected according to actual needs, and is not limited here. It is understood that when the coating layer is a multi-layer coating structure, the density is higher.

[0083] In some embodiments, the thickness of the coating layer is 1 nm to 300 nm, and the mass proportion of the coating layer in the negative electrode material is ≤ 10%. Optionally, the thickness of the coating layer can be 1 nm, 50 nm, 150 nm, 200 nm, 250 nm, and 300 nm, and the mass proportion of the coating layer in the negative electrode material can be 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here. It can be understood that the coating layer with the above thickness and mass proportion has good electrical conductivity, which can significantly improve the electrical contact performance between the active material and the current collector, accelerate the transmission speed of electrons, and thus improve the charge and discharge of the battery; at the same time, the coating layer can reduce the direct contact between the active material and the electrolyte, reduce the occurrence of side reactions, and thus improve the first coulombic efficiency and cycle stability of the battery. Preferably, the thickness of the coating layer is 1 nm to 50 nm, and more preferably, the thickness of the coating layer is 1 nm to 30 nm.

[0084] In a second aspect, the present application provides a method for preparing a negative electrode material, referring to FIG4 , the preparation method comprises the following steps:

[0085] In step S10, an oxygen-containing carbon source precursor is mixed with a nitrogen dopant to obtain a mixture, and the mixture is pre-carbonized to obtain a first precursor; wherein the mass proportion of oxygen in the mixture is ≤50%, and the mass proportion of nitrogen is ≤20%.

[0086] Step S20 , carbonizing the first precursor in a reducing atmosphere to obtain a carbon matrix; wherein the temperature of the carbonization treatment is 800° C. to 1000° C.

[0087] Step S30: Compounding the active material with the carbon matrix to obtain a composite product, wherein the negative electrode material includes the composite product.

[0088] In the above scheme, the preparation method of the negative electrode material provided by the present application, in the process of preparing the first precursor, uses oxygen and nitrogen dopants and controls the mass content of the two to provide oxygen and nitrogen elements, so that the prepared negative electrode material is doped with nitrogen and oxygen elements. After the nitrogen and oxygen elements are doped in the negative electrode material, the lone pairs of electrons on the p orbitals of the nitrogen atoms and oxygen atoms can increase the number of mobile electrons in the carbon matrix, thereby increasing the powder conductivity of the negative electrode material. The high powder conductivity can make the negative electrode material more efficient in transporting lithium ions, so that during the first charge and discharge process of the battery prepared by the negative electrode material, more lithium ions can participate in the reversible charge and discharge reaction of the battery, reducing the irreversible capacity loss of the battery, thereby improving the first coulombic efficiency of the battery prepared by the negative electrode material; at the same time, the content of nitrogen and oxygen elements in the negative electrode material is adjusted to an appropriate range through carbonization treatment, while improving the powder conductivity of the negative electrode material, reducing the effect of nitrogen and oxygen doping on the first coulombic efficiency of the negative electrode material, thereby obtaining the negative electrode material of the present application with both excellent conductive properties and high first coulombic efficiency.

[0089] The preparation method of the present application is described in detail below with reference to the examples:

[0090] In step S10, an oxygen-containing carbon source precursor and a nitrogen dopant are mixed to obtain a mixture, and the mixture is pre-carbonized to obtain a first precursor; wherein the oxygen content of the mixture is ≤50% by weight, and the nitrogen content is ≤20% by weight. It is understood that the mixing of the oxygen-containing carbon source precursor and the nitrogen dopant in air will absorb oxygen and moisture from the air.

[0091] In some embodiments, the mass proportion of oxygen in the mixture is ≤50%. Optionally, the mass proportion of oxygen in the mixture can be 10%, 20%, 30%, 40%, 50%, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here. It is understandable that the mass proportion of oxygen in the mixture is within the above range, and the doping amount of oxygen in the carbon matrix obtained after pre-carbonization treatment is within a suitable range, which can improve the powder conductivity of the carbon matrix. Preferably, the mass proportion of oxygen in the mixture is 10% to 50%.

[0092] In some embodiments, the mass proportion of nitrogen in the mixture is ≤20%. Optionally, the mass proportion of nitrogen in the mixture can be 5%, 8%, 11%, 15% and 20%, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here. It can be understood that the mass proportion of nitrogen in the mixture is within the above range, and the doping amount of nitrogen in the carbon matrix obtained after pre-carbonization treatment is within a suitable range. While improving the powder conductivity of the carbon matrix, it reduces the breakage of the π-π conjugated system caused by nitrogen doping. Preferably, the mass proportion of nitrogen in the mixture is 5% to 20%.

[0093] In some embodiments, the oxygen-containing carbon source precursor includes at least one of epoxy resin, phenolic resin, ion exchange resin, corn starch, soluble starch, sweet potato starch, cellulose and lignin. The type of oxygen-containing carbon source precursor can be selected according to actual needs and is not limited here.

[0094] In some embodiments, the nitrogen dopant includes at least one of amino acids, nitrobenzene derivatives, and aniline derivatives. The type of nitrogen dopant can be selected according to actual needs and is not limited here.

[0095] In some embodiments, the mixing time is 1 to 2 hours. Optionally, the mixing time can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, or other values ​​within the range. The mixing time can be selected according to actual needs and is not limited here. It is understood that when the mixing time is within the above range, the oxygen-containing carbon source precursor and the nitrogen dopant are mixed more evenly, so that the nitrogen and oxygen elements are evenly distributed in the carbon material, thereby improving the doping effect of the nitrogen and oxygen elements.

[0096] In some embodiments, the temperature of the pre-carbonization treatment is 600°C to 800°C. Optionally, the temperature of the pre-carbonization treatment can be 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C and 800°C, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0097] In some embodiments, the pre-carbonization treatment time is 1 hour to 6 hours. Optionally, the pre-carbonization treatment time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0098] In some embodiments, the pre-carbonization treatment is performed in a protective atmosphere, and the protective atmosphere includes at least one of nitrogen, helium, and neon. The type of protective atmosphere can be selected according to actual needs and is not limited here.

[0099] Step S20 , carbonizing the first precursor in a reducing atmosphere to obtain a carbon matrix; wherein the temperature of the carbonization treatment is 800° C. to 1000° C.

[0100] In some embodiments, the carbonization treatment is performed in a reducing atmosphere, which includes at least one of hydrogen, methane, and acetylene. The type of reducing atmosphere can be selected according to actual needs and is not limited here.

[0101] In some embodiments, the gas flow rate of the reducing atmosphere is 10 SCCM to 200 SCCM. Optionally, the gas flow rate of the reducing atmosphere can be specifically 10 SCCM, 40 SCCM, 70 SCCM, 100 SCCM, 130 SCCM, 160 SCCM, 190 SCCM and 200 SCCM, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0102] In some embodiments, the carbonization treatment time is 0.5h to 2h. Optionally, the carbonization treatment time can be 0.5h, 1h, 1.5h, 2h, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here. It is understood that when the carbonization treatment time is within the above range, the nitrogen and oxygen doping amounts in the carbon matrix obtained by the carbonization treatment are within a reasonable range, while improving the conductivity of the negative electrode material powder, reducing the breakage of the π-π conjugated system, so that the negative electrode material has both excellent electrical conductivity and high first coulombic efficiency.

[0103] Step S30: Compounding the active material with the carbon matrix to obtain a composite product, wherein the negative electrode material includes the composite product.

[0104] In some embodiments, the step of compounding the active material with the carbon matrix includes: performing silicon deposition treatment on the carbon matrix using a silicon source to obtain a negative electrode material.

[0105] In some embodiments, the silicon source includes at least one of silane and disilane. The type of silicon source can be selected according to actual needs and is not limited here.

[0106] In some embodiments, the flow rate of the silicon source is 10 SCCM to 500 SCCM. Optionally, the flow rate of the silicon source can be specifically 10 SCCM, 100 SCCM, 200 SCCM, 300 SCCM, 400 SCCM and 500 SCCM, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0107] In some embodiments, the silicon source further includes a carrier gas, and the carrier gas includes at least one of nitrogen, helium, and argon. The type of carrier gas can be selected according to actual needs and is not limited here.

[0108] In some embodiments, the silicon source also includes a carrier gas, and the flow rate of the carrier gas is 50 SCCM to 1000 SCCM. Optionally, the flow rate of the carrier gas can be 50 SCCM, 100 SCCM, 200 SCCM, 300 SCCM, 400 SCCM, 500 SCCM, 600 SCCM, 700 SCCM, 800 SCCM, 900 SCCM and 1000 SCCM, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0109] In some embodiments, the temperature of the silicon deposition process is 450°C to 750°C. Optionally, the temperature of the silicon deposition process can be 450°C, 480°C, 510°C, 540°C, 570°C, 600°C, 630°C, 660°C, 690°C, 720°C and 750°C, etc., or other values ​​within the range. It can be selected according to actual needs and is not limited here.

[0110] After step S30, the method further includes step S40, in which the composite product is coated with a coating material to obtain a negative electrode material.

[0111] It can be understood that the coating layer located at the outermost layer of the negative electrode material has good electrical conductivity, which can significantly improve the electrical contact performance between the active material and the current collector, accelerate the transmission speed of electrons, and thus improve the charge and discharge performance of the battery prepared with the negative electrode material; at the same time, the coating layer can reduce the direct contact between the active material and the electrolyte, reduce the occurrence of side reactions between the negative electrode material and the electrolyte, thereby improving the first coulombic efficiency and cycle stability of the battery prepared with the negative electrode material.

[0112] In some embodiments, the material of the coating layer includes at least one of metal oxides, carbon materials, amorphous silicon, conductive polymers, fluorides, phosphates, and nitrides.

[0113] In some embodiments, the metal oxide includes at least one of oxides of Sn, Ge, Fe, Si, Cu, Ti, Na, Mg, Al, Ca, and Zn.

[0114] In some embodiments, the carbon material includes at least one of amorphous carbon and graphitized carbon.

[0115] In some embodiments, the conductive polymer includes at least one of polyaniline, polyacetylene, polypyrrole, polythiophene, poly-3-hexylthiophene, poly(p-phenylene vinylene), polypyridine, and polystyrene vinylene.

[0116] In some embodiments, the fluoride includes at least one of vinyl fluoride, fluoropolymer, lithium fluoride, sodium fluoride, potassium fluoride, fluorocarbon polymer, fluorosilicone polymer, hexafluorobutyl acrylate, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), perfluoroalkoxy resin (PFA), polychlorotrifluoroethylene (PCTFE), ethylene monochlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF) and polyvinyl fluoride.

[0117] In some embodiments, the phosphate includes at least one of magnesium phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, chromium phosphate, cobalt phosphate, nickel phosphate, germanium phosphate, zirconium phosphate, niobium phosphate, molybdenum phosphate, tantalum phosphate, tungsten phosphate, and lanthanum phosphate.

[0118] In some embodiments, the nitride includes at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride, and carbon nitride.

[0119] In a third aspect, the present application provides a battery, comprising a negative electrode material prepared by any one of the negative electrode materials in the first aspect or any one of the negative electrode materials in the second aspect, and the negative electrode material provided in the present application has excellent conductive properties.

[0120] The following further describes the embodiments of the present invention in multiple embodiments. The embodiments of the present invention are not limited to the following specific embodiments. Appropriate changes can be made within the scope of the unchanged main rights.

[0121] Example 1

[0122] (1) Soluble starch and aniline are mixed for 2 hours to obtain a mixture, wherein the mass proportion of oxygen element in the mixture is 50% and the mass proportion of nitrogen element is 5%; and the mixture is pre-carbonized at 600° C. for 3 hours to obtain a first precursor.

[0123] (2) The first precursor was carbonized at 800°C for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0124] (3) The carbon substrate is placed in a kiln, 500 SCCM of nitrogen and 250 SCCM of silane are introduced, and silicon deposition treatment is performed at 750° C. for 5 hours to obtain a composite product, and the composite product is coated with a coating material to obtain a negative electrode material.

[0125] Example 2

[0126] Different from Example 1, the mass proportion of oxygen element in the mixture is 25%, and the mass proportion of nitrogen element is 10%.

[0127] Example 3

[0128] Different from Example 1, the mass proportion of oxygen element in the mixture is 10%, and the mass proportion of nitrogen element is 20%.

[0129] Example 4

[0130] Different from Example 2, the mixture was pre-carbonized at 700° C. for 3 h to form the first precursor.

[0131] Example 5

[0132] Different from Example 2, the mixture was pre-carbonized at 800° C. for 3 h to form the first precursor.

[0133] Example 6

[0134] Different from Example 3, the first precursor was carbonized at 900° C. for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0135] Example 7

[0136] Different from Example 3, the first precursor was carbonized at 1000° C. for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0137] Example 8

[0138] Different from Example 2, the first precursor was carbonized at 900° C. for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0139] Example 9

[0140] Different from Example 2, the first precursor was carbonized at 1000° C. for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0141] Example 10

[0142] Different from Example 2, the first precursor was carbonized at 800° C. for 2 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0143] Comparative Example 1

[0144] Different from Example 2, the first precursor was carbonized at 400° C. for 1 h in a 100 SCCM hydrogen atmosphere to obtain a carbon matrix.

[0145] Comparative Example 2

[0146] The difference from Example 1 is that the mass percentage of oxygen in the mixture is 60%, and the mass percentage of nitrogen is 25%.

[0147] 1

[0148] Test method:

[0149] (1) Test method for nitrogen and oxygen content:

[0150] Reference national standard method: Determination of oxygen content in steel - Pulsed heating inert gas melting-infrared absorption method GB / T11261-2006; Using the German Verder oxygen, nitrogen and hydrogen element analyzer ONH2000, the sample is melted in an inert atmosphere under the influence of flux. The oxygen element contained in it is reduced to carbon dioxide by the carbon in the graphite crucible. The generated carbon dioxide enters the infrared detector with the carrier gas, and the oxygen content is calculated by quantitative statistics of the changes in the carbon dioxide infrared signal; the nitrogen element contained in it is decomposed to form stable elemental nitrogen, and the generated nitrogen enters the thermal conductivity detector with the carrier gas. The nitrogen content is calculated by quantitative statistics of the changes in the heat of the thermal conductivity cell.

[0151] (2) Test method for powder conductivity:

[0152] Using Japan's Mitsubishi Chemical powder conductivity tester MCP-PD51, the four-probe method was used to determine the volume resistivity of the sample to measure the resistance of the powder under a pressure point of 20KN. Finally, the powder conductivity of the powder was calculated using the instrument program.

[0153] (3) Electrochemical performance test:

[0154] The negative electrode material and superP, LA133 were mixed into a slurry in a ratio of 70:15:15 and evenly coated on the copper foil. After drying, the electrode sheets were prepared, assembled into button batteries, and their electrochemical properties were tested on the Blue Electric Battery Test Cabinet M340A.

[0155] (4) Testing method for specific surface area of ​​materials:

[0156] The specific surface area was measured using a Micromeritics TriStar 3000 surface area and pore size analyzer.

[0157] (5) Testing method of pore volume of materials:

[0158] The test was carried out using the ASAP2460 equipment from American Micromeritics. The pore volume V was calculated using the BJH Desorption cumulative volume of pores model. Calculated within the pore size range.

[0159] Micropore and mesopore analysis was performed using the Micromeritics ASAP 2460. At liquid nitrogen temperature, the equilibrium amount of nitrogen adsorbed on a surface is correlated with properties such as pore size. By combining the relationship between the amount of adsorption and relative pressure during adsorption, various models can be fitted to calculate pore size. The software generates reports using density functional theory (DFT) to calculate pore size distribution, total pore volume, and pore volume within a specific range.

[0160] (6) Test method for average pore size of materials:

[0161] An appropriate amount of sample particles was taken and the pore diameter was measured under a transmission electron microscope (TEM).

[0162] (7) Test method for the mass content of carbon in negative electrode materials:

[0163] Using Germany's Bruker's G4 ICARUS HF infrared carbon and sulfur analyzer: the sample is burned in a high-temperature, oxygen-rich state, and the carbon and sulfur elements it contains are oxidized to carbon dioxide and sulfur dioxide, respectively. The generated gases enter the infrared detector with the carrier gas. By quantitatively analyzing the changes in the carbon dioxide signal and the sulfur dioxide signal, the carbon and sulfur content can be calculated respectively.

[0164] (8) Test method for the mass content of silicon in negative electrode materials:

[0165] Use Nanyang Xinyu SA2-9-17TP box-type atmosphere furnace: burn in an oxygen atmosphere, so that the silicon and silicon oxide in the sample react to form silicon dioxide, and the carbon is burned and converted into carbon dioxide and discharged. The silicon content is calculated by weighing.

[0166] (9) Negative electrode material compaction density test:

[0167] Using the American McNor CARVER 4350.22 powder compaction density tester, a sample of specified mass m is placed in a mold and a pressure of 1.0 T is applied. After maintaining the pressure for 30 seconds, the pressure is removed and the thickness is tested to calculate the compaction density.

[0168] (10) Test method for particle size of negative electrode material:

[0169] The D50 was measured using a laser particle size analyzer and showed a symmetrical distribution similar to a normal distribution. In the volume-based distribution, the cumulative 50% diameter is D50, and so on, the cumulative 90% diameter is D90, and the cumulative 10% diameter is D10.

[0170] Test results:

[0171] Table 2

[0172] Table 3

[0173] Test result analysis:

[0174] Table 1 lists the specific experimental parameters of Examples 1 to 10 and Comparative Examples 1 to 2, Table 2 lists the test parameters of the carbon matrix and negative electrode materials of Examples 1 to 10 and Comparative Examples 1 to 2, and Table 3 lists the performance parameters of the carbon matrix and negative electrode materials of Examples 1 to 10 and Comparative Examples 1 to 2.

[0175] It can be seen from the data of Examples 1 to 10 in Tables 1 and 2 that, within a suitable range, increasing the temperature or time of pre-carbonization can reduce the mass content of nitrogen and oxygen elements in the obtained first precursor. At the same time, the first precursor is subsequently carbonized in a reducing atmosphere. When a reducing gas such as hydrogen is introduced into the reaction system, the nitrogen and oxygen elements bound to carbon are partially reduced to form N2 and H2O and released, which can also reduce the mass content of nitrogen and oxygen elements in the negative electrode material. That is, by controlling the carbonization temperature and time, and the pre-carbonization temperature and time, the nitrogen and oxygen elements in the non-conjugated system can be removed. In this way, the damage of the nitrogen and oxygen elements in the non-conjugated system to the conjugated system is reduced, so that the nitrogen and oxygen doping amounts in the obtained negative electrode material are controlled within a reasonable range. Furthermore, the lone pairs of electrons on the p orbitals of nitrogen and oxygen atoms can participate in the π-π conjugated system of the carbon matrix to form a larger p-π conjugated system, which increases the number of mobile electrons in the carbon matrix and increases the powder conductivity of the negative electrode material, so that the relationship between the mass content of oxygen element A%, the mass content of nitrogen element B% and the powder conductivity P of the negative electrode material obtained in this application satisfies M≤5. Combined with the data in Table 3, it can be seen that when the relationship between the oxygen content (A%), nitrogen content (B%), and powder conductivity (P) in the negative electrode material satisfies the aforementioned relationship, lithium ion transmission efficiency can be maximized. Simultaneously, the impact of nitrogen and oxygen doping on the initial coulombic efficiency of the negative electrode material can be reduced, resulting in a negative electrode material with both high initial coulombic efficiency and excellent cycle capacity retention.

[0176] However, it should be noted that if the pre-carbonization or carbonization temperature is too high, it will cause the conjugated nitrogen and oxygen to decompose, resulting in a decrease in conductivity. Therefore, in order to obtain higher conductivity, the carbonization process needs to be controlled within a reasonable temperature range for this application.

[0177] Compared with Example 1, the temperature of the carbonization treatment in Comparative Example 1 is too low, which cannot fully reduce the oxygen and nitrogen contents in the carbon matrix. The mass content of nitrogen and oxygen in the negative electrode material obtained after preparation is too high. Similarly, the mass content of nitrogen and oxygen elements contained in the mixture in Comparative Example 2 is too high, and the mass content of nitrogen and oxygen in the negative electrode material finally prepared is also too high, which makes the relationship between the mass content of oxygen element A%, the mass content of nitrogen element B% and the powder conductivity P in Comparative Example 1 and Comparative Example 2 It does not satisfy M≤5, but M>5. At this time, the tetrahedral structure formed by the S and P electron orbitals of excessive nitrogen and oxygen elements will cause the carbon in the negative electrode material to deviate from the π-π conjugated plane, resulting in a reduction in π-π conjugated carbon. Moreover, groups such as COOC and CNNC formed by nitrogen and oxygen atoms and carbon will split the π-π conjugated system, further reducing the electronic conductivity of the negative electrode material. The poor conductivity of the negative electrode material causes the battery to form more solid-phase conductive interfaces during the cycle, resulting in irreversible consumption of active lithium ions. That is, the number of lithium ions that can participate in deintercalation and insertion is reduced, resulting in a decrease in the first coulombic efficiency of the battery.

[0178] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the claims. Any person skilled in the art may make several possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A negative electrode material, characterized in that The negative electrode material comprises a carbon matrix and an active material, and the negative electrode material contains oxygen and nitrogen elements; The mass content of oxygen in the negative electrode material is A%, the mass content of nitrogen in the negative electrode material is B%, the powder conductivity of the negative electrode material is PS / cm, and A, B and P satisfy the following relationship:

2. The negative electrode material according to claim 1, characterized in that The negative electrode material has at least one of the following characteristics: (1) The mass content of oxygen in the negative electrode material is 0.2% to 2%; (2) The mass content of nitrogen in the negative electrode material is 0.2% to 2%.

3. The negative electrode material according to claim 1, characterized in that The powder conductivity of the negative electrode material is 0.3S / cm to 10S / cm.

4. The negative electrode material according to claim 1, characterized in that The volume median particle size D of the negative electrode material 50 8μm~20μm.

5. The negative electrode material according to claim 1, characterized in that The specific surface area of ​​the negative electrode material is ≤100m 2 / g.

6. The negative electrode material according to claim 1, characterized in that The compaction density of the negative electrode material is 0.8 g / cm 3 ~1.2g / cm 3 .

7. The negative electrode material according to claim 1, characterized in that The negative electrode material also has at least one of the following characteristics: (1) The carbon matrix comprises at least one of amorphous carbon, graphitized carbon, mesocarbon microbeads, and carbon gel; (2) The carbon matrix includes at least one of amorphous carbon, graphitized carbon, mesocarbon microbeads, and carbon gel, wherein the amorphous carbon includes at least one of hard carbon, soft carbon, and activated carbon; (3) The carbon matrix includes at least one of amorphous carbon, graphitized carbon, mesophase carbon microbeads and carbon gel, wherein the graphitized carbon includes at least one of graphite and graphitized carbon nanotubes.

8. The negative electrode material according to claim 1, characterized in that The negative electrode material also has at least one of the following characteristics: (1) The carbon matrix has pores, and the active material is at least partially distributed in the pores of the carbon matrix; (2) The carbon matrix has pores, and the pores include mesopores and micropores.

9. The negative electrode material according to claim 1, characterized in that The negative electrode material also has at least one of the following characteristics: (1) The active material includes a silicon-based active material, and the silicon-based active material includes at least one of crystalline silicon, amorphous silicon, and composite particles of crystalline and amorphous silicon; (2) The active material includes a silicon-based active material, and the active material further includes at least one of Sn, P, S, Ge, and Pb; (3) The morphology of the active material includes at least one of point-shaped, spherical, ellipsoidal and flake-shaped.

10. The negative electrode material according to claim 1, characterized in that The surface of the negative electrode material has a coating layer, and the material of the coating layer includes at least one of metal oxide, carbon material, conductive polymer, fluoride, phosphate and nitride.

11. The negative electrode material according to claim 10, characterized in that The negative electrode material has at least one of the following characteristics: (1) The material of the coating layer includes a metal oxide, and the metal oxide includes at least one of the oxides of Sn, Ge, Fe, Si, Cu, Ti, Na, Mg, Al, Ca and Zn; (2) The material of the coating layer includes a conductive polymer, and the conductive polymer includes at least one of polyaniline, polyacetylene, polypyrrole, polythiophene, poly-3-hexylthiophene, poly(p-phenylene vinylene), polypyridine and polystyrene vinylene; (3) The material of the coating layer includes fluoride, and the fluoride includes polyvinyl fluoride, fluoropolymer, sodium fluoride, potassium fluoride, fluorocarbon polymer, fluorosilicone polymer, hexafluorobutyl acrylate, polytetrafluoroethylene, fluorinated ethylene-propylene copolymer, perfluoroalkoxy resin, polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride and polyvinyl fluoride. At least one; (4) The material of the coating layer includes phosphate, and the phosphate includes at least one of magnesium phosphate, calcium phosphate, aluminum phosphate, titanium phosphate, chromium phosphate, cobalt phosphate, nickel phosphate, germanium phosphate, zirconium phosphate, niobium phosphate, molybdenum phosphate, tantalum phosphate, tungsten phosphate and lanthanum phosphate; (5) The material of the coating layer includes nitride, and the nitride includes at least one of titanium nitride, vanadium nitride, cobalt nitride, nickel nitride and carbon nitride; (6) The material of the coating layer includes a carbon material, and the carbon material includes at least one of amorphous carbon and graphitized carbon.

12. The negative electrode material according to claim 10, characterized in that The thickness of the coating layer is 1 nm to 300 nm.

13. The negative electrode material according to claim 10, characterized in that The coating layer accounts for ≤10% by mass of the negative electrode material.

14. A battery, characterized in that: The battery comprises the negative electrode material according to any one of claims 1 to 13.

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