Composite material, and preparation method and application thereof

Abstract

The invention discloses a composite material and a preparation method and application thereof, the composite material comprises hard carbon and organic metal salt, the metal element in the organic metal salt comprises sodium or lithium, the composite material can be used for preparing an electrode of a battery, and the first coulombic efficiency, the cycle performance and the safety of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of electrode material technology, specifically to a composite material, a method for preparing the composite material, and its application. Background Technology

[0002] With the rapid development of portable electronic devices, electric vehicles, and energy systems, batteries, as the core device for energy conversion, are constantly being updated and iterated. Batteries are now widely used in consumer electronics, advanced robotics, grid-scale energy storage, electric vehicles, and other technological fields.

[0003] Hard carbon is considered a promising battery anode material due to its abundant sodium (lithium) storage sites, suitable sodium (lithium) intercalation potential, and good structural stability. However, in related technologies, batteries using hard carbon as the anode material face several challenges. First, the surface of hard carbon contains oxygen-containing functional groups and structural defects that irreversibly trap sodium or lithium ions. Second, during the first charge and discharge cycle, the electrolyte decomposes on the surface of the hard carbon to form a solid electrolyte interphase (SEI). This process continuously consumes a large amount of active sodium or lithium ions from the positive electrode, resulting in a low initial coulombic efficiency and negatively impacting the overall energy density and cost-effectiveness of the battery.

[0004] Therefore, how to provide a hard carbon-based material that can be used to prepare battery electrodes and fully utilize the advantages of hard carbon is of great significance to the development of batteries. Summary of the Invention

[0005] In view of the shortcomings of the prior art, this application provides a composite material, a method for preparing the composite material, and its application.

[0006] In a first aspect, this application provides a composite material comprising hard carbon and an organometallic salt, wherein the metal element in the organometallic salt comprises sodium or lithium.

[0007] Secondly, this application provides a method for preparing a composite material, comprising the steps of: providing hard carbon and an organometallic salt, mixing the hard carbon and the organometallic salt, and obtaining the composite material; Wherein, the hard carbon is the hard carbon in the composite material as described in the first aspect, and the organometallic salt is the hard carbon in the composite material as described in the first aspect.

[0008] Thirdly, this application provides the application of composite materials as described in the first aspect, or composite materials prepared by the method described in the second aspect, in the preparation of electrodes.

[0009] Fourthly, this application provides a battery comprising a positive electrode and a negative electrode, wherein the material of the negative electrode comprises a composite material as described in the first aspect, or a composite material prepared by the method for preparing the composite material as described in the second aspect; Optionally, the negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector, wherein the material of the negative electrode active material layer includes the composite material as described in the first aspect, or the composite material prepared by the method described in the second aspect. The battery is a lithium-ion battery, and correspondingly, the metal element in the organometallic salt is lithium; or, the battery is a sodium-ion battery, and correspondingly, the metal element in the organometallic salt is sodium.

[0010] This application provides a composite material, a method for preparing the composite material, and its application, which has the following technical effects: In the composite material of this application embodiment, organometallic salts can act as sodium or lithium supplements, and the composite material can be used to prepare battery electrodes. During the charging and discharging process of the battery, the metal ions (sodium ions or lithium ions) released by the organometallic salts can compensate for the metal ions captured by hard carbon and / or the metal ions consumed in constructing the SEI, thereby improving the first coulombic efficiency of the battery. Furthermore, the decomposition products of organometallic salts participate in the construction of an inorganic-rich SEI, which can induce the formation of a dense, stable interfacial film with high ionic conductivity, improving the continuous decomposition of the electrolyte and thus improving the cycle life of the battery. In addition, the stable interfacial film improves the uniformity of metal ion flow distribution and inhibits the formation of metal dendrites, which is beneficial to improving the safety performance of the battery. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0012] Figure 1 This is a schematic flowchart illustrating a method for preparing a composite material according to an embodiment of this application.

[0013] Figure 2 The charge / discharge voltage-capacity characteristic curves of the sodium-ion batteries in Application Example 2 and Application Comparative Example 2 are shown. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art, and the materials or reagents used in the embodiments of this application are commercially available. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this application. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0016] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Each embodiment of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0017] In the description of this application, the term "comprising" means "including but not limited to".

[0018] The terms “multiple,” “multiple times,” or similar expressions refer to two or more times, such as two, three, four, five, six, etc.

[0019] The term "and / or" encompasses any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" includes three parallel options: A, B, and A+B.

[0020] The term "inert gas" refers to a class of gases that have stable chemical properties and do not readily react with other substances at room temperature and pressure, including but not limited to one or more of nitrogen, helium, neon, argon, krypton, and xenon.

[0021] The term "D50 particle size" refers to the particle size that accounts for 50% of the total volume of a particle group, also known as the "volume median diameter." In other words, when particles are sorted from smallest to largest, the particle size that is 50% of the total volume of all particles smaller than a certain size is the D50 particle size. The D50 particle size of materials is determined according to the method described in GB-T-19077-2024, using a laser particle size analyzer.

[0022] The term "aliphatic chain hydrocarbon group" refers to an aliphatic straight-chain hydrocarbon group or an aliphatic branched-chain hydrocarbon group, and the aliphatic chain hydrocarbon group may or may not contain unsaturated bonds. An aliphatic chain hydrocarbon group is obtained by losing at least one hydrogen atom from an aliphatic chain hydrocarbon; the number of hydrogen atoms lost can be 1, 2, 3, 4, 5, etc. "C1~C30 aliphatic chain hydrocarbon group" can refer to aliphatic chain hydrocarbon groups of C1~C20, C2~C20, C1~C18, C1~C15, C1~C12, C1~C10, C1~C8, C1~C6, or C1~C4. Aliphatic chain hydrocarbon groups of C1 to C30 are, for example, alkyl groups of C1 to C20, alkyl groups of C1 to C10, alkenyl groups of C2 to C20, alkenyl groups of C2 to C10, alkynyl groups of C2 to C20, or alkynyl groups of C2 to C10. Suitable examples of “aliphatic chain hydrocarbon groups” include, but are not limited to, methyl, ethyl, vinyl, ethynyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, etc.

[0023] The term "aliphatic chain hydroxyl group" refers to a group with the general formula […]. -O- is an aliphatic chain hydrocarbon group, where O represents an oxygen atom. "C1-C30 aliphatic chain hydrocarbon oxy group" can be, for example, aliphatic chain hydrocarbon oxy group of C1-C20, C1-C18, C1-C15, C1-C12, C1-C10, C1-C8, C1-C6, or C1-C3. C1-C30 aliphatic chain hydrocarbon oxy group can be, for example, alkoxy group of C1-C20, C1-C12, C1-C8, or C1-C6. Suitable examples of aliphatic chain hydrocarbon oxy groups include, but are not limited to, methoxy, ethoxy, tert-butoxy, n-hexanoxy, n-decaalkoxy, or n-dodecanoyloxy.

[0024] The term "aliphatic cyclic hydrocarbon group" refers to an aliphatic hydrocarbon group with a cyclic structure. An aliphatic cyclic hydrocarbon group is obtained by losing at least one hydrogen atom from an aliphatic cyclic hydrocarbon. The number of hydrogen atoms lost can be 1, 2, 3, 4, 5, etc. "Aliphatic cyclic hydrocarbon group with 3 to 30 ring atoms" can be, for example, an aliphatic cyclic hydrocarbon group with 3 to 24 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 20 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 18 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 16 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 14 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 12 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 10 ring atoms, an aliphatic cyclic hydrocarbon group with 3 to 8 ring atoms, or an aliphatic cyclic hydrocarbon group with 3 to 5 ring atoms. Suitable examples of aliphatic cyclic hydrocarbon groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or adamantyl.

[0025] The term "aliphatic heterocyclic hydrocarbon group" refers to an aliphatic heterocyclic hydrocarbon group in which at least one carbon atom is replaced by a non-carbon atom. The non-carbon atom can be one or more of N, O, S, Si, and P atoms. The number of heteroatoms in the aliphatic heterocyclic hydrocarbon group is, for example, 1 to 20. "Aliphatic heterocyclic hydrocarbon group with 3 to 30 ring atoms" can be, for example, an aliphatic heterocyclic hydrocarbon group with 3 to 24 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 20 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 18 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 16 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 14 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 12 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 10 ring atoms, an aliphatic heterocyclic hydrocarbon group with 3 to 8 ring atoms, or an aliphatic heterocyclic hydrocarbon group with 3 to 5 ring atoms. Suitable examples of aliphatic heterocyclic hydrocarbon groups include, but are not limited to, cyclothioethyl, acridine, or ethylene oxide.

[0026] The term "aryl" refers to an aromatic group obtained by losing at least one hydrogen atom from an aromatic ring compound. The number of hydrogen atoms lost can be 1, 2, 3, 4, 5, 6, etc. Aryl groups can be monocyclic, fused-ring, or polycyclic. For polycyclic rings, at least one ring must be an aromatic ring system. "Aryl groups with 6 to 30 ring atoms" can be, for example, aryl groups with 6 to 26 ring atoms, aryl groups with 6 to 24 ring atoms, aryl groups with 6 to 20 ring atoms, aryl groups with 6 to 18 ring atoms, aryl groups with 6 to 16 ring atoms, aryl groups with 6 to 14 ring atoms, aryl groups with 6 to 12 ring atoms, or aryl groups with 6 to 10 ring atoms. Suitable examples of aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, fluoranthyl, triphenylene, pyrene, perylene, tetraphenyl, fluorenyl, dinaphthyl-2-phenylene, acenaphthyl and their derivatives.

[0027] The term "heteroaryl" refers to an aryl group in which at least one carbon atom is replaced by a non-carbon atom. The non-carbon atom can be one or more of N, O, S, Si, and P atoms, and the number of heteroatoms can be, for example, 1 to 20. "Heteroaryl with 5 to 30 ring atoms" can be, for example, a heteroaryl with 5 to 28 ring atoms, a heteroaryl with 5 to 24 ring atoms, a heteroaryl with 5 to 20 ring atoms, a heteroaryl with 5 to 18 ring atoms, a heteroaryl with 5 to 16 ring atoms, a heteroaryl with 5 to 14 ring atoms, a heteroaryl with 5 to 12 ring atoms, or a heteroaryl with 5 to 10 ring atoms. Suitable examples of heteroaryl groups include, but are not limited to, thiophene, furanyl, pyrrole, diazolyl, triazolyl, imidazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridineyl, pyridazinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, or carbazolyl.

[0028] The term "quinone" refers to a functional group containing a conjugated cyclohexadienedione structure. Its core characteristic is the presence of two carbonyl groups linked by a conjugated double bond to a six-membered carbon ring. A quinone group is obtained by losing at least one hydrogen atom from a quinone compound; the number of hydrogen atoms lost can be 1, 2, 3, 4, 5, 6, etc. "A quinone group with 6 to 30 ring atoms" can be, for example, a quinone group with 6 to 26 ring atoms, a quinone group with 6 to 24 ring atoms, a quinone group with 6 to 20 ring atoms, a quinone group with 6 to 18 ring atoms, a quinone group with 6 to 16 ring atoms, a quinone group with 6 to 14 ring atoms, a quinone group with 6 to 12 ring atoms, or a quinone group with 6 to 10 ring atoms. Suitable examples of quinone groups include, but are not limited to, benzoquinone, anthraquinone, or phenanthrenequinone.

[0029] The term "amino" refers to a substance with the structural formula: The group, wherein R 10 and R 20 Each time it appears, it is independently selected from hydrogen, deuterium, C1~C20 aliphatic chain hydrocarbon group, C1~C20 aliphatic chain hydrocarbon oxygen group, aliphatic cyclic hydrocarbon group with 3~20 ring atoms, aliphatic heterocyclic hydrocarbon group with 3~20 ring atoms, aryl group with 6~20 ring atoms, heteroaryl group with 5~20 ring atoms, or a combination of the aforementioned groups.

[0030] It should be noted that when describing "the combination of the aforementioned groups", when multiple groups with cyclic structures are combined, some or all of these groups may fuse to form a new cyclic group. For example, when aryl and aliphatic cyclic hydrocarbon groups are combined, the aromatic ring of the aryl group may fuse with the cyclic hydrocarbon ring of the aliphatic cyclic hydrocarbon group to form a new cyclic group.

[0031] In this application, the method for testing the specific surface area, pore volume, and pore size distribution of the material includes the following steps: degassing the material sample to be tested in a vacuum environment (pressure -0.1 MPa) at 200 °C for 10 h; then, obtaining the nitrogen adsorption-desorption isotherm of the sample at 77 K using a MicromeritcsTristar 3030 instrument; next, calculating the specific surface area using the Brunauer-Emmett-Teller method and adsorption curve branch data in the relative pressure P / P0 range of 0.005~1, and analyzing the pore volume and pore size distribution from the adsorption curve. The model for analyzing the pore volume and pore size distribution is the DensityFunctionTheory model.

[0032] This application provides a composite material comprising hard carbon and an organometallic salt, wherein the metal element in the organometallic salt includes sodium or lithium. In the composite materials of this application embodiment, organometallic salts can act as sodium or lithium replenishers. For batteries with electrode materials including composite materials, firstly, during the charging and discharging process of the battery, the metal ions (sodium ions or lithium ions) released by the organometallic salts can compensate for the metal ions captured by hard carbon and / or the metal ions consumed in constructing the SEI, thereby improving the initial coulombic efficiency of the battery; secondly, the decomposition products of organometallic salts participate in the construction of an inorganic-rich SEI, which can induce the formation of a dense, stable interfacial film with high ionic conductivity, improving the continuous decomposition of the electrolyte, thereby improving the cycle life of the battery. In addition, the stable interfacial film improves the uniformity of metal ion flow distribution and inhibits the formation of metal dendrites, which is beneficial to improving the safety performance of the battery.

[0033] In some embodiments of this application, the composite material includes a core and a coating layer covering the core. The core material includes hard carbon, and the coating layer material includes an organometallic salt. This can further improve the phenomenon of oxygen-containing functional groups and structural defects on the hard carbon surface capturing metal ions, thereby further enhancing the electrochemical performance of the composite material.

[0034] In some embodiments of this application, the organometallic salt includes a coordinating group, at least a portion of which is coordinately linked to the hard carbon, and / or at least a portion of which is electrostatically adsorbed onto the hard carbon. This can further improve the structural stability of the coating layer, thereby further enhancing the electrochemical stability of the composite material. It should be noted that a "coordinating group" refers to a group containing atoms with lone pairs of electrons, including hydroxyl, amino, mercapto, carbonyl, and sulfonic acid groups.

[0035] In some embodiments of this application, the mass ratio of hard carbon to organometallic salt in the composite material is 100:(0.5~15), for example, it can be 100:0.5, 100:1, 100:3, 100:5, 100:8, 100:10, 100:13, 100:15, or any range between the aforementioned two values. Under this condition, during the charging and discharging process of the battery, the amount of metal ions released by the organometallic salt is within a more suitable range, sufficient to compensate for the metal ions captured by the hard carbon and / or the metal ions consumed in constructing the SEI, and avoids or improves the phenomenon of excessive dendrite growth on the electrode surface, further improving the performance and safety of the battery.

[0036] To further improve the electrochemical performance of the composite material, in some embodiments of this application, the organometallic salt has the structure shown in the following general formula (Ⅰ): (A + ) m [R1-(L - ) n (Ⅰ); In general formula (Ⅰ), A + Each occurrence of m and n is independently selected from either sodium ions or lithium ions, and each occurrence of m and n is independently selected from positive integers not less than 1, and m and n are equal. - Each occurrence includes independently or ; Each occurrence of R1 independently includes, respectively, an unsubstituted or substituted C1-C30 aliphatic chain hydrocarbon group, an unsubstituted or substituted C1-C30 aliphatic chain hydroxyl group, an unsubstituted or substituted aliphatic cyclic hydrocarbon group with 3-30 ring atoms, an unsubstituted or substituted aliphatic heterocyclic hydrocarbon group with 3-30 ring atoms, an unsubstituted or substituted aryl group with 6-30 ring atoms, an unsubstituted or substituted aryl group with 5-30 ring atoms, an unsubstituted or substituted aryl group with 6-30 ring atoms, an unsubstituted or substituted aryl group with 5-30 ring atoms, an unsubstituted or substituted quinone group with 6-30 ring atoms, or a combination of the aforementioned groups; Each time R0 appears, it is independently selected from hydroxyl groups, -X、 -CX3, amino, mercapto, nitro, cyano, azide, C1-C20 aliphatic chain hydrocarbon group, C1-C20 aliphatic chain hydrocarbon oxygen group, aliphatic cyclic hydrocarbon group with 3-20 ring atoms, aliphatic heterocyclic hydrocarbon group with 3-20 ring atoms, aryl group with 6-20 ring atoms, heteroaryl group with 5-20 ring atoms, or a combination of the aforementioned groups, wherein X represents a halogen atom.

[0037] In some embodiments of this application, each occurrence of R1 independently comprises, respectively, an unsubstituted or substituted-with-at least-R0 C4-C20 aliphatic chain hydrocarbon group, an unsubstituted or substituted-with-at least-R0 C4-C20 aliphatic chain hydroxyl group, an unsubstituted or substituted-with-at least-R0 aliphatic cyclic hydrocarbon group having 3-20 ring atoms, an unsubstituted or substituted-with-at least-R0 aliphatic heterocyclic hydrocarbon group having 3-20 ring atoms, an unsubstituted or substituted-with-at least-R0 aryl group having 6-20 ring atoms, an unsubstituted or substituted-with-at least-R0 heteroaryl group having 5-20 ring atoms, an unsubstituted or substituted-with-at least-R0 quinone group having 6-20 ring atoms, or a combination of the foregoing groups. Each occurrence of R0 independently comprises, respectively, a hydroxyl group ... -X, trifluoromethyl, nitro, amino, C1-C10 alkyl, C2-C10 alkenyl, C1-C10 alkoxy, aryl with 6-10 ring atoms, heteroaryl with 5-10 ring atoms, or a combination of the aforementioned groups, wherein each occurrence of X is independently selected from F, Cl, Br or I.

[0038] In some embodiments of this application, each occurrence of R1 independently includes, respectively, an unsubstituted or substituted C8-C20 aliphatic chain hydrocarbon group, an unsubstituted or substituted C8-C20 aliphatic chain hydroxyl group, an unsubstituted or substituted aryl group with 6-10 ring atoms, an unsubstituted or substituted aryl group with 5-10 ring atoms, an unsubstituted or substituted aryl group with 6-14 ring atoms, an unsubstituted or substituted aryl group with 6-14 ring atoms, or a combination of the aforementioned groups, or a combination of the aforementioned groups. The aryl group with 6-10 ring atoms can be phenyl or naphthyl, and the heteroaryl group with 5-10 ring atoms can be furanyl, thiophene, pyrrole, pyridinyl, pyrimidinyl, benzofuranyl, benzothiophene, indole, etc.

[0039] In some embodiments of this application, the metal element in the organometallic salt is sodium. Correspondingly, the organometallic salt is selected from sodium alkyl sulfonate, sodium dodecylbenzene sulfonate, sodium aminobenzene sulfonate, sodium m-aminobenzene sulfonate, sodium p-toluene sulfonate, and sodium 3-carbon sulfonate, which have 10-18 carbon atoms. Sodium nitrobenzenesulfonate, sodium hydroxybenzenesulfonate, sodium naphthalenesulfonate, disodium 1,3-benzenedisulfonic acid, sodium anthraquinone-1-sulfonate, sodium phthalate, and disodium phthalate.

[0040] In some other embodiments of this application, the metal element in the organometal salt is lithium. Correspondingly, the organometal salt is selected from one or more of lithium alkyl sulfonate, lithium dodecylbenzene sulfonate, lithium dinonylnaphthalene sulfonate, lithium 4-methylbenzene sulfonate, lithium p-styrene sulfonate, lithium p-ethylbenzene sulfonate, and lithium phthalate, which have 10 to 18 carbon atoms.

[0041] In some embodiments of this application, the hard carbon is selected from one or more of biomass hard carbon, resin-based hard carbon, pitch-based hard carbon, and coal tar hard carbon. As an example, the hard carbon is selected from the H30 series or H35 series products of Hunan Zhongke Xingcheng Graphite Co., Ltd.

[0042] In some embodiments of this application, the D50 particle size of the hard carbon in the composite material is 5 µm to 8 µm, for example, it can be 5 µm, 6 µm, 7 µm, 8 µm or any range between two of the aforementioned values. The specific surface area of ​​the hard carbon is 3 m². 2 / g~20 m 2 / g, for example, could be 3 m 2 / g、6 m 2 / g、10 m 2 / g、15 m 2 / g、18 m 2 / g、20 m 2 / g or any two of the aforementioned values. The pore volume of hard carbon is 0.012 cm³. 3 / g~0.1 cm 3 / g, for example, could be 0.012 cm 3 / g, 0.03 cm 3 / g, 0.05cm 3 / g, 0.08 cm 3 / g, 0.1 cm 3 / g or a range between any two of the aforementioned values. The ID / IG value for hard carbon is 1.1 to 2, for example, it can be 1.11 to 1.17, with examples being 1.1, 1.15, 1.17, 1.2, 1.5, 1.8, 2 or a value between any two of the aforementioned values.

[0043] In some embodiments of this application, the D50 particle size of the composite material is 5 µm to 8 µm, for example, 5 µm, 6 µm, 7 µm, 8 µm or any two of the aforementioned values. The ID / IG value of the composite material is 0.9 to 1.08, for example, 0.97 to 1.08, with examples being 0.9, 0.93, 0.97, 1.0, 1.03, 1.05, 1.08 or any two of the aforementioned values.

[0044] This application also provides a method for preparing a composite material, which can be used to prepare any of the composite materials described above. The method for preparing the composite material includes the steps of: providing hard carbon and an organometallic salt, mixing the hard carbon and the organometallic salt, and obtaining the composite material. The hard carbon and the organometallic salt are as described above. The method for preparing the composite material has the advantages of simple process, low cost, and suitability for industrialization.

[0045] In some embodiments of this application, in case (a), the step of mixing hard carbon and organometallic salt includes: ball milling the mixture containing hard carbon and organometallic salt to obtain a composite material.

[0046] In this hybrid system, the mass ratio of hard carbon to organometallic salt is 100:(0.5~15), for example, it can be 100:0.5, 100:1, 100:3, 100:5, 100:8, 100:10, 100:13, 100:15, or any two of the aforementioned values. Under these conditions, during the charging and discharging process of the battery, the amount of metal ions released by the organometallic salt is within a more suitable range, sufficient to compensate for the metal ions captured by the hard carbon and / or the metal ions consumed in constructing the SEI, and to avoid or improve the phenomenon of excessive dendrite growth on the electrode surface, further improving the performance and safety of the battery.

[0047] To further improve the ball milling efficiency and effect, in some embodiments of this application, in case (a), the mixing system further includes a first solvent, which includes water and one or more of C1-C10 aliphatic alcohols. The C1-C10 aliphatic alcohols are selected, for example, from one or more of methanol, ethanol, ethylene glycol, propanol, glycerol, and butanol.

[0048] In some embodiments of this application, the total mass of hard carbon and organometallic salt is a first mass, and the percentage of the first mass to the total mass of the mixed system is 80% to 95%, for example, it can be 80%, 85%, 90%, 95% or any range between the two aforementioned values.

[0049] In some embodiments of this application, the ball mill rotation speed is 200 r / min to 600 r / min, for example, it can be 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min or any range between two of the aforementioned values. The ball milling time is 2 h to 10 h, for example, it can be 2 h, 5 h, 8 h, 10 h or any range between two of the aforementioned values.

[0050] In other embodiments of this application, in case (b), such as Figure 1 As shown, the step of mixing hard carbon and organometallic salts includes the following steps: S1. Mix and stir the hard carbon, organometallic salt and second solvent to obtain a slurry; S2. The slurry is dried to obtain the composite material.

[0051] In step S1, the mass ratio of hard carbon to organometallic salt is 100:(0.5~15), for example, it can be 100:0.5, 100:1, 100:3, 100:5, 100:8, 100:10, 100:13, 100:15, or any range between the aforementioned two values. Under this condition, during the charging and discharging process of the battery, the amount of metal ions released by the organometallic salt is within a more suitable range, sufficient to compensate for the metal ions captured by the hard carbon and / or the metal ions consumed in constructing the SEI, and avoids or improves the phenomenon of excessive dendrite growth on the electrode surface, further improving the performance and safety of the battery.

[0052] Step S1 can be performed in a stirring device. In order to further improve the mixing effect of hard carbon and organometallic salt, in some other embodiments of this application, the total mass of hard carbon and organometallic salt is a second mass, and the second mass accounts for 40% to 50% of the total mass of the slurry, for example, it can be 40%, 42%, 45%, 47%, 50% or any range between the two aforementioned values.

[0053] In some other embodiments of this application, the second solvent includes water and one or more of C1-C10 aliphatic alcohols, wherein the C1-C10 aliphatic alcohols are selected, for example, from one or more of methanol, ethanol, ethylene glycol, propanol, glycerol, and butanol.

[0054] In some other embodiments of this application, the mixing and stirring described in step S1 is carried out at 60°C to 90°C, for example, 60°C, 70°C, 80°C, 90°C, or any two of the aforementioned values. Under these conditions, it is more conducive to the formation of a dense and stable coating layer of organometallic salts on the surface of hard carbon.

[0055] In step S2, the drying process can be a heat treatment, which removes the solvent from the slurry by heating, thereby obtaining a solid composite material. The heat treatment can be carried out in an oven.

[0056] This application also provides an application of the composite material as described above, or the composite material prepared by the method described above, in the preparation of electrodes.

[0057] This application provides a battery comprising a positive electrode and a negative electrode. The negative electrode is made of a composite material as described above, or a composite material prepared by the same method as described above. The battery has an initial coulombic efficiency of over 88% and exhibits good cycle performance and safety.

[0058] Specifically, during the charging and discharging process of the battery, the metal ions (sodium or lithium ions) released by the organometallic salt can compensate for the metal ions captured by hard carbon and / or consumed in the construction of the SEI, thereby improving the battery's initial coulombic efficiency. The decomposition products of the organometallic salt participate in the construction of the inorganic-rich SEI, inducing the formation of a dense, stable interfacial film with high ionic conductivity. This mitigates the continuous decomposition of the electrolyte, thus improving the battery's cycle life. Furthermore, the stable interfacial film enhances the uniformity of metal ion flow distribution and suppresses the formation of metal dendrites, which is beneficial for improving battery safety performance.

[0059] Based on its geometric shape, the battery in this application embodiment can be a square battery, a cylindrical battery, a button battery, or an irregularly shaped battery. Based on its packaging form, the battery in this application embodiment can be a pouch battery or a hard-case battery. Based on its assembly form, the battery in this application embodiment can be a battery cell, a battery module, or a battery pack. Based on its operating nature and storage method, the battery in this application embodiment can be a primary battery, a secondary battery, or an activated battery. Based on the type of current-carrying ions in the battery, the battery in this application embodiment can be a lithium-ion battery or a sodium-ion battery.

[0060] In some embodiments of this application, the negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector. The material of the negative electrode active material layer includes a composite material prepared by the method described above, or a composite material as described above. The battery is a lithium-ion battery, and correspondingly, the metal element in the organometallic salt is lithium; or, the battery is a sodium-ion battery, and correspondingly, the metal element in the organometallic salt is sodium.

[0061] The negative electrode current collector includes a first surface and a second surface disposed opposite to each other along its own thickness direction, and at least one of the first surface and the second surface is provided with a negative electrode active material layer. The material of the negative electrode current collector includes, but is not limited to, copper foil, composite copper foil, or copper mesh.

[0062] In some embodiments of this application, the negative electrode active material layer further includes a negative electrode binder and a negative electrode conductive agent. The negative electrode binder and negative electrode conductive agent can be materials commonly found in the art. The negative electrode binder includes, but is not limited to, one or more of lithium polyacrylate, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, sodium alginate, polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-propylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate. The negative electrode conductive agent includes, but is not limited to, one or more of carbon black, graphite, graphene, carbon nanotubes, carbon fibers, superconducting carbon, and acetylene black.

[0063] The preparation method of the negative electrode may include the following steps: mixing and dispersing the negative electrode active material, negative electrode conductive agent, and negative electrode binder in a first dispersion medium to form a negative electrode slurry; then, coating the negative electrode slurry onto a negative electrode current collector, followed by a drying process and a rolling process to obtain the negative electrode. It should be noted that the negative electrode slurry can also be cast on a separate carrier to form a film layer, then the film layer is separated from the carrier, and then the film layer is stacked on the first surface and / or the second surface of the negative electrode current collector. The first dispersion medium includes, but is not limited to, one or more of N-methylpyrrolidone, acetone, and water.

[0064] In the battery of this application embodiment, the positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on the surface of the positive electrode current collector. It is understood that the positive electrode current collector includes a third surface and a fourth surface disposed opposite to each other along its own thickness direction, and at least one of the third surface and the fourth surface is provided with a positive electrode active material layer.

[0065] The positive current collector is made of materials including, but not limited to, metal foil or composite current collector. Metal foil includes, but is not limited to, aluminum foil, platinum foil, or palladium foil. The composite current collector includes a substrate and a metal layer. The substrate includes a third surface and a fourth surface disposed opposite each other along its thickness direction. At least one of the third surface and the fourth surface has a metal layer. The substrate material includes, but is not limited to, one or more of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, and polyethylene. The metal layer material includes, but is not limited to, one or more of aluminum, platinum, palladium, nickel, titanium, and silver.

[0066] The positive electrode active material layer comprises a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent. The positive electrode active material, positive electrode binder, and positive electrode conductive agent can be conventional materials in the art. When the battery is a lithium-ion battery, the positive electrode active material includes, but is not limited to, one or more of lithium cobalt oxide, lithium manganese oxide, lithium permanganate, lithium iron phosphate, lithium nickel oxide, lithium manganese phosphate, lithium iron manganese phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide. When the battery is a sodium-ion battery, the positive electrode active material includes, but is not limited to, one or more of metal oxides, Prussian compounds, and polyanionic compounds, wherein the chemical formula of the metal oxide is Na. x MO2, where M is a transition metal element, including but not limited to one or more of Mn, Ni, Cr, Fe, Ti, and V. Suitable examples include but are not limited to Na(Li). 1 / 3 Ti 1 / 6 Mn 1 / 2 O2, NaFeO2 and Na 2 / 3 Ni 1 / 3 Mn 1 / 2Ti 1 / 6One or more of O2; the chemical formula of Prussian compounds is Na. x M a (M b (CN)6), M a Including but not limited to one or more of Fe, Mn, and Ni, M b Suitable examples of Prussian compounds include, but are not limited to, one or more of Fe and Mn, and include, but are not limited to, Na. x Mn(Fe(CN)6); the chemical formula of the polyanionic compound is Na x A y ((XO m ) n ) z A is a metallic element with a variable valence state, including but not limited to one or more of Fe and V, X is one or more of P and S, and suitable examples of polyanionic compounds include but are not limited to one or more of Na3V2(PO4)3, NaFePO4, Na2Fe2(SO4)3 and Na4Mn(SO4)2.

[0067] It is understandable that the compounds listed above as positive electrode active materials may have a coating layer on their surface, and the coating layer material may include, but is not limited to, carbon materials.

[0068] The positive electrode binder includes, but is not limited to, one or more of polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-propylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0069] The positive electrode conductive agent includes, but is not limited to, one or more of carbon black, graphite, graphene, carbon nanotubes, carbon fibers, superconducting carbon, and acetylene black.

[0070] The preparation method of the positive electrode may include the following steps: mixing and dispersing the positive electrode active material, the positive electrode conductive agent, and the positive electrode binder in a second dispersion medium to form a positive electrode slurry; then, coating the positive electrode slurry onto a positive electrode current collector, followed by a drying process and a rolling process to obtain the positive electrode. It should be noted that the positive electrode slurry can also be cast on a separate carrier to form a film layer, then the film layer is separated from the carrier, and then the film layer is stacked on the third and / or fourth surfaces of the positive electrode current collector. The first dispersion medium includes, but is not limited to, one or more of N-methylpyrrolidone, acetone, and water.

[0071] It should be noted that the battery in this embodiment may also include other conventional structures. For example, the battery in this embodiment may also include a separator disposed between the positive and negative electrodes. The separator may be a single-layer thin film or a composite membrane with a multi-layer structure. When the separator is a composite membrane, the materials of each layer in the composite membrane may be the same or different. The materials of the separator include, but are not limited to, one or more of glass fiber, non-woven fabric, polyester, Teflon, polyethylene, polypropylene, and polytetrafluoroethylene.

[0072] The electrolyte can be a conventional electrolyte in the art, and includes metal salts and organic solvents. The organic solvents include, but are not limited to, one or more of ethylene carbonate, propylene carbonate, butyl carbonate, fluoroethylene carbonate, 1,4-butyrolactone, ethylene carbonate, propylene carbonate, propylene sulfite, propyl acetate, propyl propionate, methyl butyrate, butyl acetate, ethyl propionate, ethyl butyrate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0073] When the battery is a lithium-ion battery, the metal salt includes lithium salts, including but not limited to LiPF6, LiClO4, LiBF4, LiSbF6, LiAsF6, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiODFB, LiTFSI, LiFSI, LiCl, LiI, and LiN(C x F 2x+1 SO2)(C y F 2y+1 One or more of SO2, wherein x and y are integers from 1 to 20, and the mass of lithium salt accounts for 10% to 15% of the total mass of the electrolyte.

[0074] When the battery is a sodium-ion battery, the metal salt includes sodium salts, including but not limited to sodium hexafluorophosphate, sodium perchlorate, sodium bis(trifluoromethanesulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium difluorooxalate borate, sodium 4,5-dicyano-2-trifluoromethylimidazolium, sodium 4,5-dicyano-2-pentafluoromethylimidazolium, and sodium fluorosulfonyl (perfluorobutylsulfonyl)imide.

[0075] It should be noted that the positive electrode, negative electrode, and separator can be formed into a battery cell through a winding or stacking process. The electrolyte wets the positive and negative electrodes, and packaging one or more battery cells yields a single battery cell. The battery cell can be packaged using a rigid shell or a pouch. The rigid shell includes, but is not limited to, a metal shell or a plastic shell with high hardness. The pouch material includes, but is not limited to, one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0076] Battery cells can be assembled to form a battery module. Each battery module includes multiple battery cells arranged sequentially along a first direction and secured with fasteners. The first direction can be the length, width, or height of the battery module. It is understood that the battery module also has a housing for accommodating the multiple battery cells.

[0077] Battery modules can be assembled to form a battery pack, and each battery pack has multiple battery modules. The battery pack also includes a housing for accommodating the multiple battery modules, which can be arranged sequentially along the length or width of the housing. It is understood that the battery pack also includes some conventional components, including but not limited to battery management systems, buffers, and cooling devices.

[0078] This application also provides an application of the aforementioned battery in electronic devices, electric vehicles, and energy storage systems. The electronic devices, electric vehicles, and energy storage systems respectively employ the aforementioned battery as a power source and / or energy storage component. The electronic devices include, but are not limited to, mobile phones, computers, digital cameras, camcorders, video game consoles, smart wearable devices, drones, Bluetooth speakers, wireless headphones, security equipment, medical equipment, and aerospace equipment. The electric vehicles include, but are not limited to, electric cars, electric motorcycles, electric bicycles, electric scooters, and electric balance scooters. The energy storage systems include, but are not limited to, home energy storage systems, solar energy storage systems, wind energy storage systems, and grid-connected energy storage power stations.

[0079] The technical solutions and effects of this application will be described in detail below through specific embodiments and experimental examples. The following embodiments are only some embodiments of this application and are not intended to limit this application in any specific way.

[0080] Material Example 1 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium benzenesulfonate, wherein the mass ratio between hard carbon and sodium benzenesulfonate is 100:5, and at least a portion of the sodium benzenesulfonate is coordinated with hard carbon to form a coating layer covering the hard carbon.

[0081] The hard carbon used is a commercially available product from Hunan Zhongke Xingcheng Graphite Co., Ltd., with the product model number H30-B2. The composite material has a D50 particle size of 5.5 μm.

[0082] The method for preparing the composite material in this embodiment includes the following steps S1.1 and S1.2.

[0083] In step S1.1, 1000 g of hard carbon and 50 g of sodium benzenesulfonate were placed in a stirrer and stirred at a stirring rate of 50 r / min for 20 min. Then, 1500 mL of the first solvent, which consisted of ethanol and water (the volume ratio of ethanol to water was 1:1), was added to the stirrer. The mixture was then heated to 80 °C and stirred for 3 h to obtain a black and viscous slurry.

[0084] In step S1.2, the slurry obtained in step S1.1 is transferred to a mold, and the thickness of the slurry in the mold is 3 cm. The mold containing the slurry is then transferred to an oven at 105 °C to dry the slurry and obtain a solid composite material.

[0085] Material Example 2 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium benzenesulfonate, wherein the mass ratio of hard carbon to sodium benzenesulfonate is 100:5, and at least a portion of the sodium benzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0086] The composite material has a D50 particle size of 5.5 μm.

[0087] The method for preparing the composite material in this embodiment includes the following steps S2.1 and S2.2.

[0088] In step S2.1, 1000 g of hard carbon and 50 g of sodium benzenesulfonate are placed in an industrial planetary ball mill jar, and 200 mL of a second solvent, deionized water, is added to obtain a mixed system. Five zirconia grinding balls with a particle size of 10 mm, five zirconia grinding balls with a particle size of 15 mm, and ten zirconia grinding balls with a particle size of 20 mm are then added to the industrial planetary ball mill jar containing the mixed system.

[0089] In step S2.2, the ball mill is started and the mixture is ball-milled at a speed of 400 r / min for 8 h. The ball-milled product is then passed through a 40-mesh sieve to remove the zirconia grinding beads. The ball-milled product with the zirconia grinding beads removed is then placed in a forced-air drying oven at 80 °C to dry the product and remove the residual solvent, thus obtaining the composite material.

[0090] Material Example 3 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium benzenesulfonate, wherein the mass ratio of hard carbon to sodium benzenesulfonate is 100:0.5, and at least a portion of the sodium benzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0091] The composite material has a D50 particle size of 5.5 μm.

[0092] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "5 g of sodium benzenesulfonate".

[0093] Material Example 4 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium benzenesulfonate, wherein the mass ratio of hard carbon to sodium benzenesulfonate is 100:10, and at least a portion of the sodium benzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0094] The composite material has a D50 particle size of 5.6 μm.

[0095] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "100 g of sodium benzenesulfonate".

[0096] Material Example 5 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium benzenesulfonate, wherein the mass ratio of hard carbon to sodium benzenesulfonate is 100:15, and at least a portion of the sodium benzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0097] The composite material has a D50 particle size of 5.6 μm.

[0098] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "150 g of sodium benzenesulfonate".

[0099] Material Example 6 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium dodecylbenzenesulfonate, wherein the mass ratio of hard carbon to sodium dodecylbenzenesulfonate is 100:5, and at least a portion of the sodium dodecylbenzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0100] The composite material has a D50 particle size of 5.5 μm.

[0101] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium dodecylbenzenesulfonate (CAS No. 25155-30-0)".

[0102] Material Example 7 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium dodecyl sulfonate, wherein the mass ratio of hard carbon to sodium dodecyl sulfonate is 100:5, and at least a portion of the sodium dodecyl sulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0103] The composite material has a D50 particle size of 5.5 μm.

[0104] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium dodecyl sulfonate (CAS No. 2386-53-0)".

[0105] Material Example 8 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium 3-aminobenzenesulfonate, wherein the mass ratio of hard carbon to sodium 3-aminobenzenesulfonate is 100:5, and at least a portion of the sodium 3-aminobenzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0106] The composite material has a D50 particle size of 5.5 μm.

[0107] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium 3-aminobenzenesulfonate (CAS No. 1126-34-7)".

[0108] Material Example 9 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium p-hydroxybenzenesulfonate, wherein the mass ratio of hard carbon to sodium p-hydroxybenzenesulfonate is 100:5, and at least a portion of the sodium p-hydroxybenzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0109] The composite material has a D50 particle size of 5.5 μm.

[0110] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium p-hydroxybenzenesulfonate (CAS No. 28469-73-0)".

[0111] Material Example 10 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium anthraquinone-1-sulfonate, wherein the mass ratio of hard carbon to sodium anthraquinone-1-sulfonate is 100:5, and at least a portion of the sodium anthraquinone-1-sulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0112] The composite material has a D50 particle size of 5.5 μm.

[0113] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium anthraquinone-1-sulfonate (CAS No. 128-56-3)".

[0114] Material Example 11 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium 1-naphthalenesulfonate, wherein the mass ratio of hard carbon to sodium 1-naphthalenesulfonate is 100:5, and at least a portion of the sodium 1-naphthalenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0115] The composite material has a D50 particle size of 5.5 μm.

[0116] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium 1-naphthalenesulfonate (CAS No. 130-14-3)".

[0117] Material Example 12 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and sodium phthalate, wherein the mass ratio of hard carbon to sodium phthalate is 100:5, and at least a portion of the sodium phthalate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0118] The composite material has a D50 particle size of 5.5 μm.

[0119] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of sodium phthalate (CAS No. 15968-01-1)".

[0120] Material Example 13 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and lithium dodecylbenzenesulfonate, wherein the mass ratio of hard carbon to lithium dodecylbenzenesulfonate is 100:5, and at least a portion of the lithium dodecylbenzenesulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0121] The composite material has a D50 particle size of 5.5 μm.

[0122] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of lithium dodecylbenzenesulfonate (CAS No. 29062-27-9)".

[0123] Material Example 14 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and lithium dinonylnaphthalene sulfonate, wherein the mass ratio of hard carbon to lithium dinonylnaphthalene sulfonate is 100:5, and at least a portion of the lithium dinonylnaphthalene sulfonate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0124] The composite material has a D50 particle size of 5.5 μm.

[0125] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of lithium dinonylnaphthalenesulfonate (CAS No. 28214-91-7)".

[0126] Material Example 15 This embodiment provides a composite material and its preparation method. The composite material includes hard carbon and lithium phthalate, wherein the mass ratio of hard carbon to lithium phthalate is 100:5, and at least a portion of the lithium phthalate is coordinated with the hard carbon to form a coating layer covering the hard carbon. The hard carbon in this embodiment is the same as the hard carbon in Material Example 1.

[0127] The composite material has a D50 particle size of 5.5 μm.

[0128] Compared with the preparation method of the composite material in Material Example 1, the difference in the preparation method of the composite material in this example is that "50 g of sodium benzenesulfonate" in step S1.1 is replaced with "50 g of lithium phthalate".

[0129] Material Comparison Example 1 This comparative example provides a hard carbon material and its preparation method. The preparation method of the hard carbon material includes the following steps S3.1 and S3.2.

[0130] In step S3.1, 1000 g of hard carbon (the same as the hard carbon in Material Example 1) was placed in a stirrer and stirred at a stirring rate of 50 r / min for 20 min. Then, 1500 mL of the first solvent, which consists of ethanol and water (the volume ratio between ethanol and water is 1:1), was added to the stirrer. The mixture was then heated to 80 °C and stirred for 3 h to obtain a black and viscous slurry.

[0131] In step S3.2, the slurry obtained in step S3.1 is transferred to a mold, and the thickness of the slurry in the mold is 3 cm. The mold containing the slurry is then transferred to an oven at 105 °C to dry the slurry, thereby obtaining a solid hard carbon material.

[0132] Material Comparison Example 2 This comparative example provides a hard carbon material and its preparation method. The preparation method of the hard carbon material includes the following steps S4.1 and S4.2.

[0133] In step S4.1, 1000 g of hard carbon (the same as the hard carbon in Material Example 1) was placed in an industrial planetary ball mill jar, and 200 mL of a second solvent, deionized water, was added to obtain a mixed system. Five zirconia grinding balls with a particle size of 10 mm, five zirconia grinding balls with a particle size of 15 mm, and ten zirconia grinding balls with a particle size of 20 mm were then added to the industrial planetary ball mill jar containing the mixed system.

[0134] In step S4.2, the ball mill jar is started, and the mixture is ball-milled at a speed of 400 r / min for 8 h to remove the zirconia grinding beads and residual solvent, thereby obtaining hard carbon material.

[0135] Material Comparison Example 3 This comparative example provides a hard carbon material, which is the hard carbon in Material Example 1.

[0136] Experimental Example 1 Raman spectroscopy was performed on the composite materials in Material Examples 1 to 15 and the hard carbon materials in Comparative Examples 1 to 3. In the Raman spectroscopy, the laser wavelength was 532 nm, the actual laser output power was 10% of the maximum rated power of the laser source, and the test range was 100 cm. -1 ~3200 cm -1 .

[0137] First, the Raman spectral data of each material sample were normalized. Then, the ratio of the peak height intensities of the Raman D and G peaks was analyzed to calculate the ID / IG ratio. The smaller the ID / IG ratio, the fewer the surface defects in the material.

[0138] The test results are shown in Table 1 below: Table 1

[0139] As shown in Table 1, compared to the hard carbon materials in Comparative Examples 1 to 3, the ID / IG ratios of the composite materials in Examples 1 to 15 are smaller. Specifically, the ID / IG ratios of the composite materials in Examples 1 to 15 are 0.97 to 1.08, while the ID / IG ratios of the hard carbon materials in Comparative Examples 1 to 3 are 1.11 to 1.17. Therefore, compared to the hard carbon materials in Comparative Examples 1 to 3, the composite materials in Examples 1 to 15 have fewer defect states.

[0140] This demonstrates that in the hard carbon materials of Comparative Examples 1 to 3, at least some of the organometallic salts are coordinated with the hard carbon, and / or at least some of the organometallic salts are electrostatically adsorbed onto the hard carbon, thereby passivating the defect states of the hard carbon and reducing the number of defect states of the hard carbon.

[0141] Application Example 1 This embodiment provides a sodium-ion battery and its preparation method. The sodium-ion battery in this embodiment is a CR2032 button cell, in which a metallic sodium sheet is used as the positive electrode. The separator is a glass fiber membrane (Whatman GF / D). The electrolyte is a 1 mol / L NaPF6 solution, the solvent of which is prepared by mixing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 1:1:1. The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector. The negative electrode current collector is an aluminum foil (12 μm thick). The negative electrode active material layer includes a negative electrode active substance, a negative electrode binder, and a negative electrode conductive agent. The negative electrode active substance is the composite material in Material Example 1, the negative electrode binder is styrene-butadiene rubber and carboxymethyl cellulose, and the negative electrode conductive agent is conductive carbon black Super-P.

[0142] The preparation method of the negative electrode includes the following steps: First, the composite material in Material Example 1 is mixed in a mass ratio of 94.5:2.5:1.5:1.5 of styrene-butadiene rubber:carboxymethyl cellulose:conductive carbon black Super-P. Then, ultrapure water is added and stirred evenly to form a slurry. Next, the slurry is coated on the surface of aluminum foil. Then, the aluminum foil coated with slurry is placed in a vacuum drying oven and dried at 90 °C for 24 h. After being pressed by a 5T roller, it is pressed into a circular electrode sheet with a diameter of 12 mm by a tablet press to obtain the negative electrode.

[0143] The sodium-ion battery in this embodiment is assembled in a glove box, the gas atmosphere inside the glove box includes argon, and the total content of water and oxygen inside the glove box is less than 0.01 ppm.

[0144] Application Examples 2-12 The sodium-ion battery in application example m is basically the same as the sodium-ion battery in application example 1, except that in application example m, the negative electrode active material of the negative electrode in the sodium-ion battery is the composite material in material example m, where m is a positive integer from 2 to 12.

[0145] Taking Application Example 2 as an example, the difference between the sodium-ion battery in Application Example 1 and the sodium-ion battery in Application Example 2 is that the negative electrode active material in the sodium-ion battery is the composite material from Material Example 2. Similarly, the difference between the sodium-ion battery in Application Example 12 and the sodium-ion battery in Application Example 12 is that the negative electrode active material in the sodium-ion battery in Application Example 12 is the composite material from Material Example 12.

[0146] Application Example 13 This embodiment provides a lithium-ion battery and its preparation method. The lithium-ion battery in this embodiment is a CR2032 button cell, in which a lithium metal sheet is used as the positive electrode. The separator is a glass fiber membrane (Whatman GF / D). The electrolyte is a 1 mol / L LiPF6 solution, the solvent of which is prepared by mixing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a volume ratio of 1:1:1. The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector. The negative electrode current collector is an aluminum foil (12 μm thick). The negative electrode active material layer includes a negative electrode active substance, a negative electrode binder, and a negative electrode conductive agent. The negative electrode active substance is the composite material in Material Example 1, the negative electrode binder is styrene-butadiene rubber and carboxymethyl cellulose, and the negative electrode conductive agent is conductive carbon black Super-P.

[0147] The preparation method of the negative electrode includes the following steps: First, the composite material in Material Example 13 is mixed in a mass ratio of 94.5:2.5:1.5:1.5 of styrene-butadiene rubber:carboxymethyl cellulose:conductive carbon black Super-P. Then, ultrapure water is added and stirred evenly to form a slurry. Next, the slurry is coated on the surface of aluminum foil. Then, the aluminum foil coated with slurry is placed in a vacuum drying oven and dried at 90 °C for 24 h. After being pressed by a 5T roller, it is pressed into a circular electrode sheet with a diameter of 12 mm by a tablet press to obtain the negative electrode.

[0148] The lithium-ion battery in this embodiment is assembled in a glove box, the gas atmosphere inside the glove box includes argon, and the total content of water and oxygen inside the glove box is less than 0.01 ppm.

[0149] Application Example 14 This embodiment provides a lithium-ion battery. Compared with the lithium-ion battery in Application Example 13, the difference of the lithium-ion battery in this embodiment is that the negative electrode active material of the negative electrode in the lithium-ion battery is the composite material in Material Example 14.

[0150] Application Example 15 This embodiment provides a lithium-ion battery. Compared with the lithium-ion battery in Application Example 13, the difference of the lithium-ion battery in this embodiment is that the negative electrode active material of the negative electrode in the lithium-ion battery is the composite material in Material Example 15.

[0151] Application Comparative Example 1 This comparative example provides a sodium-ion battery. Compared with the sodium-ion battery in Application Example 1, the difference of the sodium-ion battery in this comparative example is that the negative electrode active material of the negative electrode in the sodium-ion battery is the hard carbon material in Material Comparative Example 1.

[0152] Application Comparative Example 2 This comparative example provides a sodium-ion battery. Compared with the sodium-ion battery in Application Example 1, the difference of the sodium-ion battery in this comparative example is that the negative electrode active material of the sodium-ion battery is the hard carbon material in Material Comparative Example 2.

[0153] Application Comparative Example 3 This comparative example provides a sodium-ion battery. Compared with the sodium-ion battery in Application Example 1, the difference of the sodium-ion battery in this comparative example is that the negative electrode active material of the sodium-ion battery is the hard carbon material in Material Comparative Example 3.

[0154] Application Comparative Example 4 This comparative example provides a lithium-ion battery. Compared with the lithium-ion battery in Application Example 13, the difference of the lithium-ion battery in this comparative example is that the negative electrode active material of the negative electrode in the lithium-ion battery is the hard carbon material in Material Comparative Example 1.

[0155] Application Comparative Example 5 This comparative example provides a lithium-ion battery. Compared with the lithium-ion battery in Application Example 13, the difference of the lithium-ion battery in this comparative example is that the negative electrode active material of the negative electrode in the lithium-ion battery is the hard carbon material in Material Comparative Example 2.

[0156] Application Comparative Example 6 This comparative example provides a lithium-ion battery. Compared with the lithium-ion battery in Application Example 13, the difference of the lithium-ion battery in this comparative example is that the negative electrode active material of the negative electrode in the lithium-ion battery is the hard carbon material in Material Comparative Example 3.

[0157] Experiment Example 2 The performance of the sodium-ion batteries in Application Examples 1 to 12 and Application Comparative Examples 1 to 3 was tested respectively.

[0158] The initial coulombic efficiency and specific capacity testing methods include the following steps: Under a constant temperature environment of 25 ℃, a blue-electric testing device is used for testing. Charge and discharge are performed at a current density of 0.1C (1C=300 mA / g), with two charge-discharge cycles within a voltage range of 0.01 V to 2.00 V. During the test, the initial charge specific capacity and initial discharge specific capacity of each sodium-ion battery are obtained, as well as the second discharge specific capacity, which is then used as the specific capacity. The initial coulombic efficiency of each sodium-ion battery is calculated as: Initial coulombic efficiency (ICE, %) = Initial charge specific capacity / Initial discharge specific capacity × 100%. During the test, the voltage-capacity relationship curve (sodium storage curve) of each sodium-ion battery is obtained. Figure 2 The graphs showing the relationship between voltage and capacity of sodium-ion batteries in Application Example 2 and Application Comparative Example 2 are presented.

[0159] The kinetic voltage of each sodium-ion battery is obtained. The kinetic voltage is the ratio of the integral value of the voltage plateau below 0.1 V during the discharge phase to the capacity of the plateau below 0.1 V after the first charge-discharge cycle of each sodium-ion battery.

[0160] The cycle performance test method includes the following steps: Under a constant temperature environment of 25 ℃, the test is conducted using a Blue Electric testing device. The cells are charged and discharged at a current density of 0.5C, and 50 charge-discharge cycles are performed within a voltage range of 0.001 V to 2.0 V. The initial discharge specific capacity at 0.5C and the remaining discharge specific capacity after 50 cycles are obtained for each sodium-ion battery. The capacity retention rate (%) of each sodium-ion battery is calculated as: (Remaining discharge specific capacity after 50 cycles / Initial discharge specific capacity at 0.5C) × 100%. The test results are shown in Table 2 below. Table 2

[0161] As shown in Table 2, compared with the sodium-ion batteries in Application Comparative Examples 1 to 3, the sodium-ion batteries in Application Examples 1 to 12 have superior overall performance. Specifically, the sodium-ion batteries in Application Examples 1 to 12 have higher initial charge specific capacity, initial coulombic efficiency, kinetic voltage, and capacity retention.

[0162] In the sodium-ion batteries of Application Examples 1 to 12, the initial charge specific capacity was 319.9 mAh / g to 336.7 mAh / g, the ICE was 88.9% to 91.9%, the kinetic voltage was 38 mV to 42 mV, and the capacity retention was 85.7% to 90.1%. In the sodium-ion batteries of Application Comparative Examples 1 to 3, the initial charge specific capacity was 302.4 mAh / g to 305.2 mAh / g, the ICE was 81.9% to 83.8%, the kinetic voltage was 29 mV to 30 mV, and the capacity retention was 79.1% to 80.6%.

[0163] Depend on Figure 2 It can be seen that the sodium-ion batteries in Application Example 2 and Comparative Example 2 both exhibit sloped sodium storage regions and plateau sodium storage regions during the discharge process. The sloped sodium storage region corresponds to the adsorption behavior of sodium ions, while the plateau sodium storage region corresponds to the pore-filling behavior of sodium ions. In the initial coulombic efficiency and specific capacity tests, the ICE of the sodium-ion battery in Application Example 2 reached 91.9%, significantly higher than that of the sodium-ion battery in Comparative Example 2. This may be because the organic sodium salt can compensate for the sodium ions consumed during SEI film formation, thereby forming a stable interface layer, indicating that the sodium-ion battery in Application Example 2 has better cycle stability. Furthermore, the initial charge specific capacity of the sodium-ion battery in Application Example 2 is much higher than that of the sodium-ion battery in Comparative Example 2, indicating that the sodium-ion battery in Application Example 2 has superior sodium storage capacity characteristics.

[0164] Therefore, the negative electrode of the sodium-ion battery, including the composite material provided in the embodiments of this application, or the composite material prepared by the method provided in the embodiments of this application, is beneficial to improving the performance of the sodium-ion battery. During the charging and discharging process of the battery, the sodium ions released by the organic sodium salt can compensate for the sodium ions captured by hard carbon and / or the sodium ions consumed in constructing the SEI, thereby improving the ICE of the sodium-ion battery. In addition, the decomposition products of the organic sodium salt participate in the construction of the SEI rich in inorganic substances (e.g., including NaF), which can induce the formation of a dense, stable interfacial film with high ionic conductivity, improving the continuous decomposition of the electrolyte and thus improving the cycle life of the sodium-ion battery. Furthermore, the stable interfacial film improves the uniformity of sodium ion flow distribution and inhibits the formation of sodium dendrites, which is beneficial to improving the safety performance of the sodium-ion battery.

[0165] In Comparative Examples 1 to 3, the negative electrode of the sodium-ion battery included hard carbon material. During the charging and discharging process of the sodium-ion battery, the oxygen-containing functional groups and / or structural defects on the surface of the hard carbon irreversibly captured sodium ions. Furthermore, based on the continuous decomposition of the electrolyte, the active sodium ions from the positive electrode were continuously consumed, resulting in poor overall performance of the sodium-ion battery.

[0166] Experimental Example 3 The performance of the lithium-ion batteries in Application Examples 13 to 15 and Application Comparative Examples 4 to 6 were tested respectively.

[0167] The test methods for initial coulombic efficiency and specific capacity, dynamic voltage and cycle performance are respectively performed according to the test methods in the corresponding parts of Experiment Example 2.

[0168] The test results are shown in Table 3 below: Table 3

[0169] As shown in Table 3, compared with the lithium-ion batteries in Comparative Examples 4 to 6, the lithium-ion batteries in Application Examples 13 to 15 have superior overall performance. Specifically, the lithium-ion batteries in Application Examples 13 to 15 have higher initial charge specific capacity, initial coulombic efficiency, kinetic voltage, and capacity retention.

[0170] In the lithium-ion batteries of Application Examples 13 to 15, the initial charge specific capacity was 377.6 mAh / g to 383.2 mAh / g, the ICE was 83.9% to 84.3%, the kinetic voltage was 31 mV to 32 mV, and the capacity retention was 87.6% to 88.3%. In the lithium-ion batteries of Application Comparative Examples 4 to 6, the initial charge specific capacity was 345.7 mAh / g to 346.7 mAh / g, the ICE was 78.9% to 80.1%, the kinetic voltage was 22 mV to 24 mV, and the capacity retention was 80.6% to 81.0%.

[0171] Therefore, it can be seen that the negative electrode of the lithium-ion battery, including the composite material provided in the embodiments of this application, or the composite material prepared by the method provided in the embodiments of this application, is beneficial to improving the performance of the lithium-ion battery. During the charging and discharging process of the battery, the lithium ions released by the organic lithium salt can compensate for the lithium ions captured by hard carbon and / or the lithium ions consumed in constructing the SEI, thereby improving the ICE of the lithium-ion battery. In addition, the decomposition products of the organic lithium salt participate in the construction of the SEI rich in inorganic substances (such as LiF), which can induce the formation of a dense, stable interface film with high ionic conductivity, improve the continuous decomposition of the electrolyte, and thus improve the cycle life of the lithium-ion battery. Furthermore, the stable interface film improves the uniformity of lithium ion flow distribution and suppresses the formation of lithium dendrites, which is beneficial to improving the safety performance of the lithium-ion battery.

[0172] In Comparative Examples 4 to 6, the negative electrode of the lithium-ion battery included hard carbon material. During the charging and discharging process of the lithium-ion battery, the oxygen-containing functional groups and / or structural defects on the surface of the hard carbon irreversibly captured lithium ions, and based on the continuous decomposition of the electrolyte, it continuously consumed the active lithium ions from the positive electrode, resulting in poor overall performance of the lithium-ion battery.

[0173] The foregoing has provided a detailed description of a composite material, a method for preparing the composite material, and its applications, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in each of the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A composite material, characterized by, The composite material comprises hard carbon and an organic metal salt, wherein the metal element in the organic metal salt comprises sodium or lithium.

2. The composite material of claim 1, wherein, The composite material comprises an inner core and a coating layer covering the inner core, the material of the inner core comprises the hard carbon, and the material of the coating layer comprises the organic metal salt. Optionally, at least part of the organic metal salt is electrostatically adsorbed on the hard carbon; and / or the organic metal salt comprises a coordination group, and at least part of the organic metal salt is connected to the hard carbon by coordination.

3. The composite material of claim 1, wherein, In the composite material, the mass ratio between the hard carbon and the organic metal salt is 100:(0.5-15).

4. The composite material of claim 1, wherein, The organic metal salt has the following general formula (I): (A + ) m [R1-(L - ) n ](I); In general formula (I), A + each occurrence is independently selected from a sodium ion or a lithium ion, m and n are each occurrence independently selected from a positive integer not less than 1, and m and n are equal, L - each occurrence is independently selected from a sodium ion or a lithium ion, m and n are each occurrence independently selected from a positive integer not less than 1, and m and n are equal, L or ; R1independently at each occurrence comprises a C1-C30 aliphatic chain hydrocarbon group unsubstituted or substituted with at least one R0, a C1-C30 aliphatic chain hydrocarbonoxy group unsubstituted or substituted with at least one R0, a 3-30-membered aliphatic cyclic hydrocarbon group unsubstituted or substituted with at least one R0, a 3-30-membered aliphatic heterocyclic hydrocarbon group unsubstituted or substituted with at least one R0, a 6-30-membered aromatic group unsubstituted or substituted with at least one R0, a 5-30-membered heteroaromatic group unsubstituted or substituted with at least one R0, a 6-30-membered quinone group unsubstituted or substituted with at least one R0, or a combination of the aforementioned groups; R0is independently selected at each occurrence from hydroxyl, -X, -CX3, amino, mercapto, nitro, cyano, azido, a C1-C20 aliphatic chain hydrocarbon group, a C1-C20 aliphatic chain hydrocarbonoxy group, a 3-20-membered aliphatic cyclic hydrocarbon group, a 3-20-membered aliphatic heterocyclic hydrocarbon group, a 6-20-membered aryl group, a 5-20-membered heteroaryl group, or a combination thereof, wherein X represents a halogen atom; Represents the connection site.

5. The composite material of claim 4, wherein, R1independently at each occurrence comprises a C4-C20 aliphatic chain hydrocarbon group unsubstituted or substituted with at least one R0, a C4-C20 aliphatic chain hydrocarbonoxy group unsubstituted or substituted with at least one R0, a 3-20-membered aliphatic cyclic hydrocarbon group unsubstituted or substituted with at least one R0, a 3-20-membered aliphatic heterocyclic hydrocarbon group unsubstituted or substituted with at least one R0, a 6-20-membered aromatic group unsubstituted or substituted with at least one R0, a 5-20-membered heteroaromatic group unsubstituted or substituted with at least one R0, a 6-20-membered quinone group unsubstituted or substituted with at least one R0, or a combination of the aforementioned groups; R0is independently selected at each occurrence from hydroxyl, - X, trifluoromethyl, nitro, amino, C1-C10alkyl, C2-C10alkenyl, C1-C10alkoxy, aryl having 6-10 ring atoms, heteroaryl having 5-10 ring atoms, or a combination of the foregoing; X is independently selected at each occurrence from F, Cl, Br, or I; Optionally, R1independently at each occurrence comprises a C8-C20 aliphatic chain hydrocarbon group unsubstituted or substituted with at least one R0, a C8-C20 aliphatic chain hydrocarbonoxy group unsubstituted or substituted with at least one R0, a 6-10-membered aromatic group unsubstituted or substituted with at least one R0, a 5-10-membered heteroaromatic group unsubstituted or substituted with at least one R0, a 6-14-membered quinone group unsubstituted or substituted with at least one R0, or a combination of the aforementioned groups, or a combination of the aforementioned groups.

6. The composite material according to any one of claims 1 to 5, characterized in that, The metal element in the organic metal salt is sodium, and correspondingly, the organic metal salt is selected from sodium alkyl sulfonates with carbon atom number of 10-18, sodium dodecyl benzene sulfonate, sodium aminobenzene sulfonate, sodium m-aminobenzene sulfonate, sodium p-toluene sulfonate, 3 one or more of sodium nitrobenzene sulfonate, sodium hydroxybenzene sulfonate, sodium naphthalene sulfonate, 1,3-benzenedisulfonic acid disodium salt, sodium anthraquinone-1-sulfonate, sodium phthalate, and disodium phthalate; Alternatively, the metal element in the organic metal salt is lithium, and correspondingly, the organic metal salt is selected from one or more of lithium alkylsulfonate with a carbon atom number of 10-18, lithium dodecylbenzenesulfonate, lithium dinonylnaphthalene sulfonate, lithium 4-methylbenzenesulfonate, lithium p-styrenesulfonate, lithium p-ethylbenzenesulfonate, and lithium phthalate.

7. The composite material of claim 1, wherein, In the composite material, the D50 particle size of the hard carbon is 5 µm~8 µm, the specific surface area of the hard carbon is 3 m 2 / g~20 m 2 / g, the pore volume of the hard carbon is 0.012 cm 3 / g~0.1 cm 3 / g, and the ID / IG value of the hard carbon is 1.1~2. and / or, the D50 particle size of the composite material is 5 µm~8 µm, and the ratio of ID / IG of the composite material is 0.9~1.

08.

8. A method of producing a composite material, characterized by, comprising the steps of: providing a hard carbon and an organic metal salt, mixing the hard carbon and the organic metal salt to obtain the composite material; wherein the hard carbon is the hard carbon in the composite material as claimed in any one of claims 1 to 7, and the organic metal salt is the organic metal salt in the composite material as claimed in any one of claims 1 to 7.

9. The method of claim 8, wherein the composite material is prepared by a process comprising: In case (a), the step of mixing the hard carbon and the organic metal salt comprises: ball milling a mixed system comprising the hard carbon and the organic metal salt to obtain the composite material; wherein in the mixed system, the mass ratio between the hard carbon and the organic metal salt is 100:(0.5~15); alternatively, in case (b), the step of mixing the hard carbon and the organic metal salt comprises the following steps: mixing and stirring the hard carbon, the organic metal salt and a second solvent to obtain a slurry; and drying the slurry to obtain the composite material; wherein in the step of mixing and stirring the hard carbon, the organic metal salt and the second solvent, the mass ratio between the hard carbon and the organic metal salt is 100:(0.5~15).

10. The method of claim 9, wherein the composite material is prepared by a process comprising: In case (a), the mixed system further comprises a first solvent, the first solvent comprising one or more of water and C1~C10 aliphatic alcohol compounds; the total mass of the hard carbon and the organic metal salt is a first mass, the percentage of the first mass in the total mass of the mixed system being 80%~95%; the rotation speed of the ball milling is 200 r / min~600 r / min, and the ball milling time is 2 h~10 h; alternatively, in case (b), the total mass of the hard carbon and the organic metal salt is a second mass, the percentage of the second mass in the total mass of the slurry being 40%~50%; the second solvent comprises one or more of water and C1~C10 aliphatic alcohol compounds; the mixing and stirring is carried out at 60 ℃~90 ℃.

11. Use of the composite material as claimed in any one of claims 1 to 7, or the composite material prepared by the method as claimed in any one of claims 8 to 10, in the preparation of an electrode.

12. A battery, characterized by The battery comprises a positive electrode and a negative electrode, the material of the negative electrode comprising the composite material as claimed in any one of claims 1 to 7, or the composite material prepared by the method as claimed in any one of claims 8 to 10; Optionally, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector, the material of the negative electrode active material layer comprising the composite material as claimed in any one of claims 1 to 7, or the composite material prepared by the method as claimed in any one of claims 8 to 10; Optionally, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector, the material of the negative electrode active material layer comprising the composite material as claimed in any one of claims 1 to 7, or the composite material prepared by the method as claimed in any one of claims 8 to 10; The battery is a lithium ion battery, and correspondingly, the metal element in the organic metal salt is lithium; or the battery is a sodium ion battery, and correspondingly, the metal element in the organic metal salt is sodium.

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