Soft and hard carbon composite material, preparation method and application thereof and lithium ion battery

Abstract

The invention discloses a soft and hard carbon composite material, a preparation method and application thereof and a lithium ion battery. The preparation method comprises the following steps: drying a mixed solution of halogenated hydrocarbon plastic and cellulose-containing biomass to obtain a precursor; and carbonizing the precursor to obtain the soft and hard carbon composite material. The preparation method is simple, efficient, low in cost and suitable for industrial production, and kilogram-level manufacturing can be achieved; the prepared soft and hard carbon composite material has excellent reversible capacity, long cycle stability and rate capability, and remarkably breaks through the theoretical limit of graphite.

Description

Technical Field

[0001] This invention specifically relates to a soft and hard carbon composite material, its preparation method, application, and lithium-ion battery. Background Technology

[0002] Carbon-based anode materials are a crucial component of current lithium / sodium-ion batteries. Graphite-based materials are widely used due to their structural stability and low cost, but their theoretical specific capacity is limited (e.g., graphite's is 372 mAh / g), making it difficult to meet the demands of high-energy-density energy storage devices. In recent years, hard carbon materials have attracted attention due to their higher specific capacity and excellent rate performance, but their low initial coulombic efficiency and low compaction density limit their industrial application. While soft carbon materials possess good conductivity and cycle stability, their capacity is generally lower than that of hard carbon. Therefore, developing novel carbon materials that combine high capacity, high initial efficiency, and long cycle life has become a research hotspot in the energy storage field.

[0003] To address these issues, researchers have attempted to combine soft carbon with hard carbon, leveraging the high conductivity of soft carbon and the high capacity of hard carbon to create a synergistic effect. However, current common material modification methods often fall short in addressing these inherent contradictions. Simply mechanically mixing soft and hard carbon frequently results in macroscopic phase separation due to insufficient interfacial compatibility, and it is also difficult to form effective structural coordination at the microscale, leading to a kinetic imbalance between the surface-dominated soft carbon regions and the diffusion-controlled hard carbon regions.

[0004] Therefore, developing a soft and hard carbon material with controllable process, stable structure, and significantly improved specific capacity has important application value in the field of energy storage. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a soft and hard carbon composite material, its preparation method, applications, and a lithium-ion battery. The preparation method of this invention is simple, efficient, low-cost, and suitable for industrial production, enabling kilogram-level manufacturing. The prepared soft and hard carbon composite material exhibits superior reversible capacity, long-cycle stability, and rate performance, significantly exceeding the theoretical limits of graphite.

[0006] This invention constructs a soft-hard carbon composite framework through in-situ co-pyrolysis of haloalkanes plastics and biomass precursors. The haloalkanes plastics serve as the soft carbon source, while cellulose-containing biomass acts as the hard carbon source. The abundant hydroxyl groups on the biomass skeleton act as in-situ anchoring sites, reacting with halogen atoms in the haloalkanes plastics. Intermolecular interactions transform the haloalkanes plastics into a robust cross-linked network, synergistically regulating the evolution of the microstructure. Chemical cross-linking during pyrolysis regulates grain orientation and significantly expands the interlayer spacing. This results in a synergistically reconstructed soft-hard carbon composite with a vortex-layered structure, exhibiting excellent reversible capacity and long-term cycling stability.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0008] This invention provides a method for preparing a soft and hard carbon composite material, which includes the following steps:

[0009] A precursor is obtained by drying a mixture of halogenated hydrocarbon plastics and cellulose-containing biomass; the precursor is then carbonized to obtain the soft and hard carbon composite material.

[0010] In this invention, the halogenated hydrocarbon plastic refers to a polymer formed by polymerization of halogenated olefin monomers or copolymerization with other monomers, in which some hydrogen atoms in the molecule are replaced by halogens. The halogenated hydrocarbon plastic preferably includes linear halogenated hydrocarbon polymers and / or cyclic halogenated hydrocarbon polymers. The linear halogenated hydrocarbon polymer refers to a polymer with a linear molecular chain structure formed by polymerization of halogenated olefins (such as vinyl chloride, tetrafluoroethylene, etc.) as monomers; the cyclic halogenated hydrocarbon polymer generally refers to a halogenated hydrocarbon polymer with a cyclic structure in its molecule. The halogen in the halogenated hydrocarbon plastic is generally one or more of fluorine, chlorine, bromine, and iodine.

[0011] The linear halogenated hydrocarbon polymer preferably includes one or more of polyvinyl chloride, polyvinylidene fluoride, polyvinylidene fluoride, polyvinylidene chloride, and polytetrafluoroethylene.

[0012] The viscosity number K value of the polyvinyl chloride can be 80-50, preferably 70-55, for example 62-60.

[0013] In this invention, the cellulose-containing biomass may be one or more of the following: cotton, coconut shell, pine wood, poplar wood, bamboo, flax, ramie, sugarcane bagasse, rice straw, and wheat straw.

[0014] In this invention, the solvent in the mixture can be a conventional solvent in the art that can dissolve halogenated hydrocarbon plastics, such as NMP.

[0015] In this invention, the mass ratio of the halogenated hydrocarbon plastic to the cellulose-containing biomass can be (0.1-4):1, for example 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1 or 3:1.

[0016] In this invention, the concentration of halogenated hydrocarbon plastics in the mixture can be (0.01-5) g / mL, for example 0.02 g / mL, 0.03, 0.04, 0.06, 0.08, 0.1, 0.2, 0.5, 1 or 2.

[0017] In this invention, the method for preparing the mixture of halogenated hydrocarbon plastics and cellulose-containing biomass preferably includes the following process: after uniformly mixing the halogenated hydrocarbon plastics and solvent, cellulose-containing biomass is added and mixed.

[0018] The mixing method can be conventional in the art, such as stirring.

[0019] In the process of mixing the halogenated hydrocarbon plastic and the solvent, the mixing temperature can be 20-50℃, for example 25℃, 30℃ or 35℃; the mixing time can be 10-60min, for example 15min, 20min or 30min.

[0020] During the process of adding biomass containing cellulose and mixing, the mixing temperature can be 25-90℃, for example 30℃, 40℃, 50℃, 55℃ or 60℃; the mixing time can be 20-90min, for example 25min, 30min, 45min or 60min.

[0021] In this invention, the method for preparing the mixture of halogenated hydrocarbon plastics and cellulose-containing biomass preferably includes the following process: after mixing the halogenated hydrocarbon plastics and solvent evenly at room temperature, adding the cellulose-containing biomass and mixing at 25-90°C.

[0022] In this invention, the drying operation and conditions can be conventional in the art, such as drying in an oven. The drying temperature can be 60-180℃, for example 80℃, 100℃, 120℃ or 140℃; the drying time can be 6-24h, for example 12h.

[0023] In this invention, the precursor is preferably ground into powder before carbonization.

[0024] In this invention, the carbonization is generally carried out under an inert atmosphere that does not react with the reaction system, such as nitrogen or argon. The carbonization is generally carried out in a tube furnace. The carbonization temperature is preferably 700-1200°C, for example, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, or 1150°C. The carbonization time is preferably 1-6 hours, for example, 2 hours, 3 hours, or 4 hours. The rate of heating to the carbonization temperature can be 2-10°C / min, for example, 5°C / min. After carbonization, the material is generally allowed to cool naturally to room temperature.

[0025] The present invention also provides a soft and hard carbon composite material prepared by the preparation method described above.

[0026] In this invention, the soft and hard carbon composite material preferably has a vortex-like layered structure internally. The interlayer spacing of the soft and hard carbon composite material is preferably 0.36-0.37 nm. The specific surface area of ​​the soft and hard carbon composite material is preferably 5-8 m². 2 / g, for example, 6 m 2 / g, 6.4m 2 / g or 7 m 2 / g.

[0027] The present invention also provides an application of the soft and hard carbon composite material as described above in lithium-ion batteries.

[0028] The present invention also provides a lithium-ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the negative electrode comprises a soft and hard carbon composite material as described above.

[0029] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0030] The reagents and raw materials used in this invention are all commercially available.

[0031] The positive and progressive effects of this invention are as follows:

[0032] The preparation method of this invention is simple, efficient, low-cost, and suitable for industrial production, enabling kilogram-level manufacturing. The prepared soft and hard carbon composite materials exhibit excellent reversible capacity, long-cycle stability, and rate performance, significantly exceeding the theoretical limits of graphite. Attached Figure Description

[0033] Figure 1 Infrared spectra of the precursors prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0034] Figure 2 SEM image of the soft and hard carbon composite material prepared in Example 1;

[0035] Figure 3 TEM image of the soft and hard carbon composite material prepared in Example 1;

[0036] Figure 4 TEM image of the soft and hard carbon composite material prepared in Comparative Example 1;

[0037] Figure 5 HRTEM images of the carbon materials prepared in Comparative Examples 1 and 2 and the soft and hard carbon composite materials prepared in Example 1. Detailed Implementation

[0038] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0039] The cotton (degreased cotton) used in the following experiments was purchased from Shandong Dingtai Information Technology Co., Ltd.; the coconut shell material was purchased from Suzhou Yituolian International Trade Co., Ltd.; the polyvinyl chloride (PVC) was purchased from Aladdin, with a viscosity of K62-60; and the polyvinylidene chloride (PVDC) was grade RG and branded as Adamas.

[0040] Example 1

[0041] 10 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP). The mixture was stirred at room temperature (25°C) for 30 minutes, then 10 g of cotton was added, and the temperature was raised to 50°C with stirring for another 30 minutes to obtain a precursor mixture. The precursor mixture was then dried in an oven at 120°C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0042] Example 2

[0043] 10 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP), stirred at room temperature for 30 minutes, then 10 g of cotton was added, the temperature was raised to 50 °C, and stirring was continued for another 30 minutes to obtain a precursor mixture. The precursor mixture was placed in an oven and dried at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 900℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0044] Example 3

[0045] 10 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP), stirred at room temperature for 30 minutes, then 10 g of cotton was added, the temperature was raised to 50 °C, and stirring was continued for another 30 minutes to obtain a precursor mixture. The precursor mixture was placed in an oven and dried at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1100℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0046] Example 4

[0047] 5 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP), stirred at room temperature for 30 minutes, then 10 g of cotton was added, the temperature was raised to 50 °C, and stirring was continued for another 30 minutes to obtain a precursor mixture. The precursor mixture was placed in an oven and dried at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0048] Example 5

[0049] 20g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP). After stirring at room temperature for 30 minutes, 10g of cotton was added, and the temperature was raised to 50℃ with continued stirring for another 30 minutes to obtain a precursor mixture. The precursor mixture was then dried in an oven at 120℃ for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5℃ for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0050] Example 6

[0051] 10 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP) and stirred at room temperature for 30 minutes. Then, 10 g of dried and pulverized coconut shell (particle size 10-20 μm) was added, and the mixture was heated to 50 °C and stirred for another 30 minutes to obtain a precursor mixture. The precursor mixture was then dried in an oven at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0052] Example 7

[0053] 10 g of PVDC was dissolved in 250 mL of N-methylpyrrolidone (NMP). The mixture was stirred at room temperature (25°C) for 30 minutes, then 10 g of cotton was added, and the temperature was raised to 50°C with stirring for another 30 minutes to obtain a precursor mixture. The precursor mixture was then dried in an oven at 120°C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5°C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a soft and hard carbon composite material.

[0054] Comparative Example 1

[0055] 10 g of PVC was dissolved in 250 mL of N-methylpyrrolidone (NMP), stirred at room temperature for 30 minutes, and then dried in an oven at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a carbon composite material.

[0056] Comparative Example 2

[0057] 10 g of cotton was dissolved in 250 mL of N-methylpyrrolidone (NMP), stirred at room temperature for 30 minutes, and then dried in an oven at 120 °C for 12 hours to obtain the precursor. Subsequently, the precursor was ground into powder and carbonized in a tube furnace at 5 °C for 1 minute under an argon atmosphere. -1 The temperature was increased to 1000℃ at a certain rate and held for 3 hours; after the carbonization reaction was completed, it was naturally cooled to room temperature to obtain a carbon composite material.

[0058] Effect Example

[0059] (1) Morphological and structural characterization

[0060] Figure 1 The infrared spectra of the precursors prepared in Example 1, Comparative Example 1, and Comparative Example 2 are shown below. Figure 1 It can be seen that the precursor prepared in Example 1 is approximately 1400 cm⁻¹ -1 The appearance of new characteristic peaks at the location indicates that cross-linking and hydrogen bonding have formed between the hydroxyl groups in the biomass and the chlorine atoms in the PVC. Furthermore, XRD analysis of the precursors prepared in Example 1, Comparative Example 1, and Comparative Example 2 revealed that the precursor of Comparative Example 1 exhibited two characteristic peaks corresponding to PVC; the precursor of Comparative Example 2 showed broad diffraction peaks, indicating its amorphous properties; the precursor of Example 1 possessed characteristics of both Comparative Example 1 and Comparative Example 2, but its peak intensity was lower than that of Comparative Example 2, indicating that intermolecular interactions inhibited the formation of long-range ordered polymer crystals.

[0061] Figure 2 The image shows the SEM image of the soft and hard carbon composite material prepared in Example 1. As can be seen from the image, the soft and hard carbon composite material prepared in Example 1 exhibits an irregular particle morphology, with a smooth fracture surface and no obvious macroscopic pores.

[0062] Figure 3 The image shows a TEM image of the soft and hard carbon composite material prepared in Example 1. Figure 3 It can be seen that the material has a dense solid structure, with closed pores and ordered carbon layers distributed alternately. Figure 4 The TEM image shows the soft and hard carbon composite material prepared in Comparative Example 1. Figure 4 It can be seen that the carbon material prepared in Comparative Example 1 exhibits a layered stacked structure.

[0063] Figure 5 HRTEM images of the carbon materials prepared in Comparative Examples 1 and 2 and the soft and hard carbon composite materials prepared in Example 1, based on... Figure 5 It can be seen that the carbon material in Comparative Example 1 exhibits long-range ordered stripes with an interlayer spacing of 0.321 nm; Comparative Example 2 exhibits a short-range disordered structure with an interlayer spacing of 0.349 nm; while Example 1 exhibits a vortex layered structure with an interlayer spacing of 0.368 nm.

[0064] Characterized by nitrogen adsorption-desorption, the specific surface area of ​​the soft and hard carbon composite material prepared in Example 1 was 6.4 m². 2 / g, while the carbon materials in Comparative Examples 1 and 2 were 2.7 m. 2 / g and 4.3 m 2 / g.

[0065] (2) Electrochemical performance testing

[0066] Half-cell: The soft and hard carbon composite materials prepared in Examples 1-7 and the carbon materials prepared in Comparative Examples 1-2 were used as active materials. The active materials, carbon black, and sodium alginate were mixed at a mass ratio of 8:1:1, and NMP solvent was added. The mixture was then dispersed evenly in a homogenizer to obtain a slurry. The slurry was coated onto copper foil and dried overnight in a vacuum oven at 80 °C. Subsequently, the obtained copper foil was cut into circular battery electrodes with a diameter of 12 mm for later use, with an average mass loading of approximately 2 mg / cm³. -2 Electrochemical performance was evaluated using a 2016 coin cell, which consists of a lithium metal sheet as the counter electrode, a Celgard 2500 membrane, and 1.0 mol L⁻¹. -1 The LiPF6 electrolyte composition (DEC:EC volume ratio 1:1, containing 10% FEC and 1% VC by volume) was used. The test system was LAND-CT2001A at 0.01–3 V (Li... + Within the / Li) voltage window, constant current cycling tests were performed at a rate of 0.1 C (30 mA / g). Charge-discharge tests were conducted at different current densities using a LAND-CT2001A test system. Cyclic voltammetry curves were measured in the range of 0.01–3.0 V using a CHI760E electrochemical workstation (Shanghai Chenhua). 1 C = 300 mAh g -1 The test results are shown in Tables 1 and 2.

[0067] For the 2016 coin cell, an aluminum foil slurry containing 80% LiFePO4, 10% carbon black, and 10% polyvinylidene fluoride (PVDF) was deposited as the positive electrode. No pre-lithiation treatment was performed on the positive and negative electrodes before battery assembly. The electrolyte was a 1.0 M LiPF6 solution, with EC, DMC, and EMC in a 1:1:1 volume ratio as solvents, containing 5% FEC by volume. The N / P ratio was approximately 1.2.

[0068] Table 1. First charge-discharge performance at 0.2C rate in half-cells

[0069]

[0070] As shown in Table 1, the reversible capacity of the soft and hard carbon composite material prepared in this invention significantly exceeds the theoretical capacity of graphite (372 mAh g⁻¹). -1 The soft-hard carbon composite material prepared in Example 1 exhibited excellent rate performance in a half-cell, maintaining 413 mAh g⁻¹ at 0.5C. -1 At 1C, it is 376 mAh g. -1 At 2C, it is 321 mAh g. -1 At 5C, it is 273 mAh g. -1 At 10C, it is 226 mAh g. -1 When the current returns to 0.2C, the capacity recovers to 467 mAh g. -1 Furthermore, maintaining 100% capacity retention confirms that the expanded interlayer space facilitates rapid lithium-ion transport.

[0071] Table 2 Cycling performance at 1C rate for 200 cycles in a half-cell.

[0072]

[0073] As shown in Table 2, the soft and hard carbon composite materials prepared by this invention exhibit excellent cycling performance. In Example 1, the capacity retention rate is approximately 100% after 200 cycles at 1C; after 2000 cycles at 5C, the capacity remains essentially at 289 mAh g⁻¹. -1 .

[0074] In a full cell composed of lithium iron phosphate, it exhibited excellent performance under long-term cycling tests at 1C rate, remaining stable across a wide rate range from 0.1C to 4C, and providing 147 mAh g⁻¹ at 0.1C. -1 The capacity remains at 113 mAh g, even at high 4C rates. -1 The capacity.

[0075] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for preparing a soft and hard carbon composite material, characterized in that, Includes the following steps: A precursor is obtained by drying a mixture of halogenated hydrocarbon plastics and cellulose-containing biomass; the precursor is then carbonized to obtain the soft and hard carbon composite material.

2. The method for preparing the soft and hard carbon composite material as described in claim 1, characterized in that, The halocarbon plastics include linear halocarbon polymers and / or cyclic halocarbon polymers; The linear halogenated hydrocarbon polymer preferably includes one or more of polyvinyl chloride, polyvinylidene fluoride, polyvinylidene fluoride, polyvinylidene chloride, and polytetrafluoroethylene. And / or, the cellulose-containing biomass is one or more of cotton, coconut husk, pine wood, poplar wood, bamboo, flax, ramie, sugarcane bagasse, rice straw, and wheat straw.

3. The method for preparing the soft and hard carbon composite material as described in claim 1, characterized in that, The mass ratio of the halogenated hydrocarbon plastic to the cellulose-containing biomass is (0.1-4):1, for example, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1 or 3:1; And / or, the concentration of halogenated hydrocarbon plastics in the mixture is (0.01-5) g / mL, for example 0.02 g / mL, 0.03, 0.04, 0.06, 0.08, 0.1, 0.2, 0.5, 1 or 2.

4. The method for preparing the soft and hard carbon composite material as described in claim 1, characterized in that, The preparation method of the mixture of halogenated hydrocarbon plastics and cellulose-containing biomass includes the following process: after the halogenated hydrocarbon plastics and solvent are mixed evenly, cellulose-containing biomass is added and mixed.

5. The method for preparing the soft and hard carbon composite material as described in claim 4, characterized in that, During the process of mixing the halogenated hydrocarbon plastics and the solvent, the mixing temperature is 20-50°C, for example, 25°C, 30°C or 35°C. And / or, during the process of adding biomass containing cellulose, the mixing temperature is 25-90°C, for example 30°C, 40°C, 50°C, 55°C or 60°C.

6. The method for preparing the soft and hard carbon composite material as described in claim 1, characterized in that, The carbonization temperature is 700-1200℃, for example 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃ or 1150℃; And / or, the carbonization time is 1-6 hours, for example 2 hours, 3 hours or 4 hours.

7. A soft and hard carbon composite material prepared by the method for preparing a soft and hard carbon composite material as described in any one of claims 1-6.

8. The soft and hard carbon composite material as described in claim 7, characterized in that, The soft and hard carbon composite material satisfies one or more of the following conditions: (1) The soft and hard carbon composite material has a vortex layered structure inside; (2) The interlayer spacing of the soft and hard carbon composite material is 0.36-0.37 nm; (3) The specific surface area of ​​the soft and hard carbon composite material is 5-8 m². 2 / g.

9. The application of a soft and hard carbon composite material as described in claim 7 or 8 in a lithium-ion battery.

10. A lithium-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode comprises a soft and hard carbon composite material as described in claim 7 or 8.

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