Composite carbon source porous carbon, silicon-carbon composite material, preparation method and application thereof, and battery

Abstract

The invention discloses composite carbon source porous carbon, a silicon-carbon composite material, a preparation method and application of the silicon-carbon composite material and a battery. The preparation method of the composite carbon source porous carbon comprises the following steps: heating a mixed solution of vinasse and an acid solution to obtain pretreated vinasse; carrying out heating treatment on the mixed solution of the pretreated vinasse and the alkali solution to obtain alkali-treated vinasse; and reacting a mixed solution containing the alkali-treated vinasse, PVC and alkaline earth metal powder at room temperature, and sequentially washing, granulating, pre-carbonizing and carbonizing to obtain the composite carbon source porous carbon. The preparation method disclosed by the invention can realize pollution-free treatment and high-added-value utilization of the halogen-containing polymer waste and the distillers' grains, and has the advantages of high efficiency, environmental protection, greenness, energy conservation and the like; the prepared composite carbon source porous carbon has high conductivity and high porosity, and also has excellent electrochemical performance when being applied to batteries.

Description

Technical Field

[0001] The present invention belongs to the field of new energy materials, and particularly relates to a composite carbon source porous carbon, a silicon-carbon composite material, a preparation method, an application thereof, and a battery. Background Art

[0002] Against the backdrop of the continuously increasing global demand for clean energy, lithium-ion batteries, as important energy storage devices, the optimization of their performance has become a research hotspot. As a key component of lithium-ion batteries, the anode material plays a decisive role in the performance of the battery, such as energy density and cycle life. Porous carbon materials have become a highly potential choice for anode materials due to their high specific surface area, good chemical stability, and unique pore structure. However, the preparation of traditional porous carbon materials faces many challenges.

[0003] On the one hand, most of the raw materials used in traditional porous carbon preparation processes are fossil resources, such as asphalt, coal, etc. These fossil raw materials not only have limited reserves, and overexploitation will cause damage to the environment, but also have high costs, which is not conducive to large-scale production. At the same time, the preparation process often relies on complex chemical reagents and harsh reaction conditions, which not only increase the production cost, but also easily generate a large amount of waste and pollutants, and do not conform to the concepts of green chemistry and sustainable development.

[0004] On the other hand, existing porous carbon materials have deficiencies in performance. During the charge and discharge process of lithium-ion batteries, the electrode material needs to undergo multiple volume changes. However, the structural stability of traditional porous carbon materials is poor and it is difficult to withstand this repeated volume change, resulting in easy damage to the electrode structure, thereby affecting the cycle life of the battery. In addition, its conductivity and pore size distribution are also not satisfactory, and it cannot meet the requirements for the rapid transmission of lithium ions in the electrode material, limiting the charge and discharge efficiency of the battery.

[0005] In view of the above problems, it is urgent to develop a preparation method for porous carbon materials that is green, environmentally friendly, low-cost, and has excellent performance. Summary of the Invention

[0006] The present invention precisely aims to solve the above technical problems and provides a composite carbon source porous carbon and silicon carbide A composite material, a preparation method, an application thereof, and a battery. The preparation method of the composite carbon source porous carbon in the present invention can realize the pollution-free treatment and high-value utilization of halogen-containing polymer waste and distiller's grains, and has advantages such as high efficiency, environmental protection, greenness, and energy saving; the prepared composite carbon source porous carbon has high conductivity and high porosity, and also has excellent electrochemical performance when applied in a battery.

[0007] This method first performs acid treatment on the distillers' grains to remove impurities and optimize the biomass component structure, then performs alkali treatment to create pores, and then mixes it with PVC (polyvinyl chloride) and alkaline earth metal powder for reaction, followed by granulation, pre-carbonization, and carbonization to obtain composite carbon source porous carbon. The addition of PVC can bond the distillers' grains particles to form a stable particle structure, alleviating the collapse and damage of the pore structure of the distillers' grains; the addition of alkaline earth metal powder can catalyze the dehalogenation reaction of PVC and crosslink, and after carbonization, porous carbon with a multi-level pore structure can be formed. In addition, the alkaline earth metal salts (such as MgCl2) formed during the dehalogenation process can fix halogens, forming a highly conductive hard carbon structure during carbonization at a lower temperature, which is energy-saving and environmentally friendly, while improving the conductivity and mechanical properties of the porous carbon; the alkaline earth metal salts and the unreacted alkaline earth metal powder form pore structures after washing removal, which can increase the porosity and pore volume. Thus, the prepared composite carbon source porous carbon material has high conductivity and pore volume. This preparation method can achieve pollution-free treatment and high-value utilization of halogen-containing polymer waste and distillers' grains, and has advantages such as high efficiency, environmental protection, greenness, and energy saving.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The present invention provides a preparation method for composite carbon source porous carbon, which includes the following steps:

[0010] (1) After heating the mixture of distillers' grains and acid solution, pretreated distillers' grains are obtained;

[0011] (2) After heating the mixture of the pretreated distillers' grains and alkali solution, alkali-treated distillers' grains are obtained;

[0012] (3) After reacting the mixed solution containing the alkali-treated distillers' grains, PVC, and alkaline earth metal powder at room temperature, washing, granulation, pre-carbonization, and carbonization are carried out in sequence to obtain the composite carbon source porous carbon.

[0013] In step (1), the distillers' grains can be one or more of white liquor distillers' grains, beer distillers' grains, yellow rice wine distillers' grains, and grape wine distillers' grains. Generally, the distillers' grains need to be dried before use. The moisture content of the dried distillers' grains is preferably less than 5%.

[0014] In step (1), the acid solution preferably includes one or more of sulfuric acid, hydrochloric acid, and phosphoric acid. The concentration of the acid solution can be 0.5 - 3M, preferably 1 - 2M, such as 1M.

[0015] In step (1), the mass ratio of the distillers' grains to the acid solution can be 1:(1 - 5), such as 1:2, 1:3, or 1:4.

[0016] In step (1), the equipment used for the heating treatment can be conventional in the art, for example, carried out in a constant temperature heating magnetic stirrer.

[0017] In step (1), the temperature of the heat treatment can be 50 - 100 °C, such as 60 °C, 70 °C or 80 °C. The time of the heat treatment can be 1 - 5 h, such as 2 h, 2.5 h, 3 h or 4 h.

[0018] In step (1), according to the routine in the art, after the heat treatment, filtration, washing and drying are generally required. The washing is generally carried out with deionized water until neutral.

[0019] In step (2), the alkali solution can include an aqueous solution containing one or more of sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate and sodium carbonate. The concentration of the alkali solution can be 0.5 - 2 M, such as 1 M.

[0020] In step (2), the mass ratio of the pretreated distiller's grains to the alkali solution can be 1:(0.5 - 10), such as 1:3, 1:4, 1:5, 1:6 or 1:8.

[0021] In step (2), the equipment used for the heat treatment can be conventional in the art, for example, carried out in a constant temperature water bath.

[0022] In step (2), the temperature of the heat treatment can be 40 - 100 °C, such as 60 °C, 70 °C or 80 °C. The time of the heat treatment can be 1 - 6 h, such as 3 h, 4 h or 5 h.

[0023] In step (2), according to the routine in the art, after the heat treatment, filtration, washing and drying are generally required. The washing can generally be carried out with deionized water until neutral.

[0024] In step (3), the alkaline earth metal powder can be magnesium powder or calcium powder. The particle size of the alkaline earth metal powder can be 1 - 30 μm.

[0025] In step (3), the mass ratio of the alkali-treated distiller's grains to the PVC can be 10:(0.5 - 5), such as 10:1, 10:2, 10:3 or 10:4.

[0026] In step (3), the mass ratio of the alkali-treated distiller's grains to the alkaline earth metal powder can be 10:(0.1 - 1), such as 10:0.3, 10:0.5 or 10:0.8.

[0027] In step (3), the solvent in the mixed solution is preferably NMP and / or DMF. The mass ratio of the sum of the masses of the alkali-treated distiller's grains, PVC and alkaline earth metal powder to the mass of the solvent in the mixed solution can be (0.2 - 3):1, such as 1:1.

[0028] In step (3), the room temperature generally refers to 15 - 35°C, such as 25°C.

[0029] In step (3), the reaction time at room temperature can be 10 min - 1 h, such as 30 min. The reaction generally takes place in a mixed state. The mixing method can be conventional in the art, such as stirring. The mixing speed can be 100 - 600 rpm, such as 200 rpm, 300 rpm or 400 rpm.

[0030] In step (3), the operation and conditions of the washing can be conventional in the art, such as washing with deionized water.

[0031] In step (3), granulation can be carried out by using a sieve to form particles or by using a spray dryer for granulation. According to the convention in the art, after granulation and before pre - carbonization, a drying treatment is generally required.

[0032] In some specific embodiments, the granulation preferably includes the following process: in an inert gas atmosphere, use an electric stirrer to stir the powder into a viscous paste, and then form particles through a sieve. The inert gas can be conventional in the art, such as nitrogen.

[0033] In step (3), the pre - carbonization and the carbonization are generally carried out under the protection of an inert gas. The inert gas is, for example, argon or nitrogen.

[0034] In step (3), the temperature of the pre - carbonization is preferably 90 - 400°C, such as 120°C, 200°C, 250°C, 300°C or 350°C. The time of the pre - carbonization is preferably 1 - 6 h, such as 2 h, 2.5 h, 3 h or 4 h.

[0035] In step (3), the temperature of the carbonization is preferably 450 - 900°C, such as 500°C, 600°C, 700°C or 800°C. The time of the carbonization is preferably 4 - 12 h, such as 5 h, 7 h, 8 h or 10 h.

[0036] In step (3), according to the convention in the art, after the carbonization, washing, drying and screening are generally required. The conditions of the washing and the drying can be conventional in the art. The solvent used for washing can be ethanol and / or deionized water. The mesh number of the sieve used for screening can be 100 - 400 meshes, such as 200 meshes.

[0037] The present invention also provides a composite carbon - source porous carbon prepared by the preparation method as described above.

[0038] In the present invention, the composite carbon - source porous carbon preferably has both a porous carbon structure and a hard - carbon structure at the same time.

[0039] The present invention also provides a method for preparing a silicon-carbon composite material, which comprises the following steps:

[0040] The composite carbon source porous carbon as described above is subjected to silane deposition to obtain a silicon-carbon composite material.

[0041] In the present invention, the composite carbon source porous carbon generally needs to be washed and activated before use. The process of washing and activation preferably comprises the following steps: after pickling the composite carbon source porous carbon, it is then dried, degassed under vacuum, and calcined.

[0042] Among them, the acid used for pickling can be hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid or acetic acid. The concentration of the acid used for pickling can be 0.1 - 5M, such as 0.5M, 1M or 2M. The pickling time can be 20 - 60 min, such as 30 min or 50 min. The amount of the acid used in the pickling process can be conventional in the art, and generally it can just submerge the composite carbon source porous carbon. The pickling is generally carried out in a mixed state (such as ultrasonic or stirring). After pickling, it generally needs to be washed with deionized water until neutral.

[0043] Among them, for the vacuum degassing, it generally needs to be evacuated to below 5×10-3 Pa.

[0044] Among them, the calcination is generally carried out in an inert atmosphere. The calcination temperature can be 300 - 500 °C, such as 400 °C. The calcination time can be 0.5 - 4 h, such as 1 h or 2 h. According to the convention in the art, generally no cooling is required after calcination for silane deposition.

[0045] In the present invention, the temperature of the silane deposition can be 400 - 600 °C, such as 500 °C or 550 °C. The time of the silane deposition can be 1 - 4 h, such as 1 h or 2 h.

[0046] In the present invention, the silane deposition is preferably carried out in a mixed gas of silane and an inert gas. The flow rate of the silane is preferably 10 - 50 sccm, such as 20 sccm, 25 sccm or 30 sccm. The flow rate of the inert gas is preferably 50 - 200 sccm, such as 100 sccm, 120 sccm or 150 sccm.

[0047] Among them, the total pressure of the mixed gas can be 100 - 2000 Pa, such as 200 Pa or 500 Pa.

[0048] In a specific embodiment, during the silane deposition process, the silane flow rate is 20 sccm and the argon flow rate is 100 sccm.

[0049] The present invention also provides a silicon-carbon composite material prepared by the preparation method as described above.

[0050] The present invention also provides an application of the composite carbon source porous carbon or silicon carbide composite material as described above in electricity Applications in the battery.

[0051] The present invention also provides a battery, which comprises the composite carbon source porous carbon or silicon-carbon composite material as described above.

[0052] In the present invention, the battery can be conventional in the art, for example, a lithium-ion battery.

[0053] On the basis of conforming to the common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0054] The reagents and raw materials used in the present invention are all commercially available.

[0055] The positive and progressive effects of the present invention are as follows:

[0056] The present invention utilizes the distiller's grains biological waste and PVC waste that are difficult to be resourcefully utilized to prepare porous carbon through high-value resource utilization. By using PVC to bond the distiller's grains particles to form a stabilized structure, and combining methods such as metal-catalyzed low-temperature dehalogenation, acid-base activation for pore formation, the action of metal and salt templates, and gradient carbonization, a porous carbon material with high conductivity and high porosity is formed, realizing the optimization of the conductive network of the carbon skeleton and the precise regulation of the pore structure, providing a negative electrode solution with both low cost and high performance for high-energy density energy storage devices, and the preparation method has advantages such as high efficiency, environmental protection, greenness, and energy saving; the prepared composite carbon source porous carbon has high conductivity and high porosity, and also has excellent electrochemical performance when applied in the battery. Description of the Drawings

[0057] Figure 1 SEM image of the composite carbon source porous carbon prepared in Example 1;

[0058] Figure 2 SEM image of the porous carbon material prepared in Comparative Example 1. Detailed Description of the Invention

[0059] The present invention will be further illustrated by the following examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to the conventional methods and conditions, or selected according to the product specifications.

[0060] Example 1

[0061] (1) Pretreatment of distiller's grains: Select distiller's grains (Zhengyu, Sichuan), place them in an electrothermal blast drying oven, and dry them at 80 °C until the moisture content is less than 5%. Weigh the dried distiller's grains and mix them with a 1 M sulfuric acid solution at a mass ratio of 1:3, put them into a thermostatic heating magnetic stirrer with heat collection, and heat at 70 °C for 3 h. After heating, use a circulating water multi-purpose vacuum pump with a common funnel for filtration, wash the filter residue repeatedly with deionized water until neutral, and then put it into an electrothermal blast drying oven to dry, obtaining pretreated distiller's grains.

[0062] (2) Alkaline treatment for pore expansion: Mix the pretreated distiller's grains with a 1 M sodium hydroxide aqueous solution at a mass ratio of 1:5, put them into a digital display constant temperature water bath, and heat at 70 °C for 4 h. After heating, filter, wash the mixture with deionized water until neutral, and then dry.

[0063] (3) Material compounding and granulation: Weigh and mix the powder of distiller's grains after alkaline treatment, PVC (model SG-5, from Qilu Petrochemical Company), and ultrafine magnesium powder (purity 99%, Lanabai, 10 μm) at a mass ratio of 10:3:0.5, and then slowly add them to NMP (J&K Scientific) solvent (the mass ratio of the mixed powder to the solvent is 1:1). At room temperature, stir and react at a speed of 300 rpm for 30 min, then filter, and wash the filter residue repeatedly with deionized water three times; then use an electric stirrer to stir the filter residue into a paste in a nitrogen atmosphere, and then make wet particles through a sieve, and place them in a vacuum drying oven to dry.

[0064] (4) Carbonization: Carry out staged carbonization of the particles prepared in step (3) in a tubular furnace under an argon atmosphere. In the first stage of pre-carbonization, after introducing 1000 sccm argon into the tubular furnace for 30 min, then raise the temperature to 300 °C under the condition of continuously introducing argon and keep it warm for 3 h; in the second stage of carbonization, continue to raise the temperature to 800 °C based on the temperature of the first stage of pre-carbonization and keep it warm for 8 h. After carbonization, naturally cool to room temperature, wash the obtained product repeatedly with deionized water, then put it into an electrothermal blast drying oven to dry at 80 °C, and finally screen through a 200-mesh sieve to obtain a composite carbon source porous carbon material.

[0065] Example 2

[0066] Compared with Example 1, except that the distiller's grains (Zhengyu, Sichuan) are replaced with brewer's grains (Hengxin, Zhenjiang), the rest of the operations and conditions are the same as those in Example 1.

[0067] Example 3

[0068] Compared with Example 1, except that the heating time after mixing with acid in step (1) is adjusted to 2 h, the rest of the operations and conditions are the same as those in Example 1.

[0069] Example 4

[0070] Compared with Example 1, except that the heating time after mixing with alkali in step (2) was adjusted to 2 h, the remaining operations and conditions were the same as those in Example 1.

[0071] Example 5

[0072] Compared with Example 1, except that the mass ratio of the distillers grains powder, PVC, and ultrafine magnesium powder after alkali treatment in step (3) was adjusted to 10:1:0.5, the remaining operations and conditions were the same as those in Example 1.

[0073] Example 6

[0074] Compared with Example 1, except that the time of the first-stage pre-carbonization in step (4) was adjusted to 2 h, the remaining operations and conditions were the same as those in Example 1.

[0075] Comparative Example 1

[0076] Compared with Example 1, except that PVC was not added in step (2), the remaining operations and conditions were the same as those in Example 1.

[0077] Comparative Example 2

[0078] Compared with Example 1, except that magnesium powder was not added in step (2), the remaining operations and conditions were the same as those in Example 1.

[0079] Comparative Example 3

[0080] Compared with Example 1, except that neither PVC nor magnesium powder was added in step (2), the remaining operations and conditions were the same as those in Example 1.

[0081] Comparative Example 4

[0082] Compared with Example 1, except that the pretreatment of the distillers grains in step (1) was not carried out, the remaining operations and conditions were the same as those in Example 1.

[0083] Comparative Example 5

[0084] Compared with Example 1, except that the alkali treatment for pore expansion in step (2) was not carried out, the remaining operations and conditions were the same as those in Example 1.

[0085] Comparative Example 6

[0086] Compared with Example 1, except that the first-stage pre-carbonization in step (4) was not carried out, the remaining operations and conditions were the same as those in Example 1.

[0087] Effect Example

[0088] (1) SEM and BET tests

[0089] Figure 1 SEM image of the composite carbon source porous carbon material prepared in Example 1; Figure 2 SEM image of the porous carbon material prepared in Comparative Example 1. It can be seen from Figure 1 and Figure 2 that the uniformity of the surface morphology and the integrity of the particles of the porous carbon material prepared in Example 1 are significantly improved compared with those in Comparative Example 1. Since PVC can play a bonding role during granulation, the stability of the particle surface and interior is enhanced. The porous carbon materials prepared in Examples 1 to 6 and Comparative Examples 1-6 were respectively subjected to BET tests using an ASAP2020 specific surface area and pore size analyzer, and the test results are shown in Table 1.

[0090] (2) Electrochemical performance test

[0091] The porous carbon materials prepared in Examples 1 to 6 and Comparative Examples 1-6 were respectively used to prepare silicon-carbon composite materials by silane deposition. The preparation method is as follows: First, the porous carbon material was immersed in 0.5M dilute hydrochloric acid and ultrasonically treated for 50 minutes (power 200W), then rinsed with deionized water until neutral and dried at 100°C for 6 hours, and then placed in a tubular furnace for vacuum degassing. Argon was introduced (flow rate 100 sccm), and the temperature was raised to 400°C and held for 1 hour; then the temperature was continued to be raised to 550°C for silane deposition in a mixed gas of silane and argon, with a silane flow rate of 20 sccm, an argon flow rate of 100 sccm, a total pressure of 200 Pa, and a deposition time of 120 minutes. After deposition, it was sealed and stored in a glove box.

[0092] The electrochemical test method is as follows: The silicon-carbon composite material, conductive carbon black, and sodium carboxymethyl cellulose prepared above were mixed at a mass ratio of 80:10:10, added with deionized water to make a slurry, coated on a 10-μm thick copper foil, vacuum dried at 120°C for 12 hours, and then punched into an electrode sheet with a diameter of 12 mm. The negative electrode sheet was metallic lithium. A 1 mol / L LiPF6 electrolyte (the solvent was EC, DMC, and FEC, EC:DMC = 1:1 (volume ratio), and FEC accounted for 5% of the total volume of the solvent) was used to assemble a CR2032 button battery in an argon glove box, and a constant current charge / discharge test was carried out on a LAND CT2001A battery test system. The test voltage range was 0.01-1.5V (vs. Li / Li+), and the current density was 0.1C (1C = 2000 mA / g). The test results are shown in Table 1:

[0093] Table 1

[0094]

[0095] According to the results in Table 1, the silicon-carbon composite material prepared from the highly conductive porous carbon material prepared by the present invention has excellent discharge specific capacity and cycling performance. In Comparative Example 1, due to the lack of PVC as a pyrolysis precursor and the inability to form a PVC highly conductive pyrolytic hard carbon coating structure due to the lack of cross-linking effect, the mechanical properties of the particles are poor, the structure is loose, the conductivity is poor, and the rate performance is poor. In Comparative Example 2, the lack of magnesium powder makes it difficult for PVC to undergo dehalogenation reaction, and it is impossible to further create pores through magnesium powder, resulting in a decrease in specific surface area, a decrease in silicon deposition amount, and a decrease in the capacity and rate of the silicon-carbon negative electrode. In Comparative Example 3, due to the simultaneous lack of PVC and magnesium powder, the cross-linking effect cannot be achieved, the dehalogenation reaction of PVC and the pore-forming effect of magnesium powder cannot occur, and the capacity and rate performance of the material decrease significantly. In Comparative Example 4, since the distiller's grains were not pretreated, a large amount of lignin, hemicellulose and metal ion impurities remained in the distiller's grains, seriously affecting the formation of nanopores and the electrode performance. In Comparative Example 5, alkali pore-forming was not carried out, the specific surface area of the material was low, the number of pores was small, and the silicon deposition amount was significantly reduced. In Comparative Example 6, pre-carbonization was not carried out, resulting in too fast pyrolysis rate of the precursor, easy destruction of the pore structure, and inability to form a nanoporous carbon structure.

[0096] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing composite carbon source porous carbon, characterized in that: It includes the following steps: (1) heating a mixture of vinasse and acid solution to obtain pretreated vinasse; (2) heating the mixture of the pretreated vinasse and the alkaline solution to obtain alkaline-treated vinasse; (3) reacting a mixed solution containing the alkali-treated vinasse, PVC and alkaline earth metal powder at room temperature, and then washing, granulating, pre-carbonizing and carbonizing in sequence to obtain the composite carbon source porous carbon.

2. The method for preparing composite carbon source porous carbon according to claim 1, characterized in that: Step (1) satisfies one or more of the following conditions: (1) The wine trough is one or more of a white wine trough, a beer trough, a yellow wine trough and a grape wine lees; (2) The acid solution includes one or more of sulfuric acid, hydrochloric acid and phosphoric acid; (3) The concentration of the acid solution is 0.5-3M, preferably 1-2M, for example 1M; (4) The mass ratio of the lees to the acid solution is 1:(1-5), for example 1:2, 1:3 or 1:4; (5) The temperature of the heating treatment is 50-100°C, for example, 60°C, 70°C or 80°C; (6) The heating treatment time is 1-5 h, for example 2 h, 2.5 h, 3 h or 4 h; (7) After the heating treatment, filtering, washing and drying are required; the washing is preferably performed using deionized water until it becomes neutral.

3. The method for preparing composite carbon source porous carbon according to claim 1, characterized in that: Step (2) satisfies one or more of the following conditions: (1) The alkaline solution includes an aqueous solution containing one or more of sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate and sodium carbonate; (2) The concentration of the alkaline solution is 0.5-2M, for example 1M; (3) The mass ratio of the pretreated vinasse to the alkaline solution is 1:(0.5-10), for example, 1:3, 1:4, 1:5, 1:6 or 1:8; (4) The temperature of the heating treatment is 40-100°C, for example 60°C, 70°C or 80°C; (5) The heating treatment time is 1-6 hours, for example 3 hours, 4 hours or 5 hours.

4. The method for preparing composite carbon source porous carbon according to claim 1, characterized in that: Step (3) satisfies one or more of the following conditions: (1) The alkaline earth metal powder is magnesium powder or calcium powder; (2) The mass ratio of the alkali-treated vinasse to the PVC is 10:(0.5-5), for example, 10:1, 10:2, 10:3 or 10:4; (3) The mass ratio of the alkali-treated vinasse to the alkaline earth metal powder is 10:(0.1-1), for example, 10:0.3, 10:0.5 or 10:0.8; (4) The solvent in the mixed solution is NMP and / or DMF; (5) The ratio of the sum of the mass of the alkali-treated vinasse, PVC and alkaline earth metal powder to the mass of the solvent in the mixed solution is (0.2-3):1, for example 1:1; (6) The reaction time at room temperature is 10 min-1 h, for example 30 min; (7) The granulation is performed by using a screen to form granules or by using a spray dryer; Preferably, the granulation comprises the following process: in an inert gas atmosphere, using an electric stirrer to stir the powder into a paste, and then passing the powder through a sieve to form granules.

5. The method for preparing composite carbon source porous carbon according to claim 1, characterized in that: Step (3) satisfies one or more of the following conditions: (1) The pre-carbonization temperature is 90-400°C, for example, 120°C, 200°C, 250°C, 300°C or 350°C; (2) The pre-carbonization time is 1-6 hours, for example 2 hours, 2.5 hours, 3 hours or 4 hours; (3) The carbonization temperature is 450-900°C, for example, 500°C, 600°C, 700°C or 800°C; (4) The carbonization time is 4-12 hours, for example 5 hours, 7 hours, 8 hours or 10 hours; (5) After the carbonization is completed, washing, drying and screening are required; the mesh size of the sieve used for screening is 100-400 mesh.

6. A method for preparing a silicon-carbon composite material, characterized in that: It includes the following steps: The composite carbon source porous carbon as claimed in claim 5 is subjected to silane deposition to obtain a silicon-carbon composite material.

7. The method for preparing the silicon-carbon composite material according to claim 6, characterized in that: The preparation method meets one or more of the following conditions: (1) The composite carbon source porous carbon needs to be cleaned and activated before use; The cleaning and activation process preferably includes the following steps: acid-washing the composite carbon source porous carbon, and then drying, vacuum degassing, and calcining; the acid used in the acid-washing is preferably hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid or acetic acid; the concentration of the acid used in the acid-washing is preferably 0.1-5M; the time of the acid-washing is preferably 20-40min; the temperature of the calcination is preferably 300-500°C; the time of the calcination is preferably 0.5-4h; (2) The temperature of the silane deposition is 400-600° C.; (3) The silane deposition time is 1-4 hours; (4) The silane deposition is carried out in a mixed gas of silane and an inert gas; the flow rate of the silane is preferably 10-50 sccm.

8. A silicon-carbon composite material obtained by the method for preparing a silicon-carbon composite material as claimed in claim 6 or 7.

9. Use of the composite carbon source porous carbon as claimed in claim 5 or the silicon-carbon composite material as claimed in claim 8 in a battery.

10. A battery, characterized in that: It includes the composite carbon source porous carbon as claimed in claim 5 or the silicon-carbon composite material as claimed in claim 8.

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