Composite Lithium Storage Material for Lithium-Ion Batteries, Preparation Method Thereof, and Application

Abstract

Provided are a composite lithium storage material for a lithium ion battery, a preparation method thereof, and an application thereof. 【Solution means】The composite lithium storage material includes a spherical porous graphitizable carbon material and nanosilicon grown in situ within the pores of the spherical porous graphitizable carbon material. The nanosilicon is vaporized from micron-sized silicon powder by a high-frequency plasma processing apparatus and then grows in situ within the pores of the porous graphitizable carbon material. The particle size of the nanosilicon is 0.1 nm to 50 nm, and the mass percentage of the nanosilicon in the silicon-graphitizable carbon composite material is 1% to 70%. In the composite lithium storage material according to the present invention, with the porous graphitizable carbon material as the matrix, more nanosilicon particles can be deposited in the through pores, so it has a higher compression density, further increases the charge specific capacity of the material, is more advantageous for the insertion and desorption of lithium ions in the charge-discharge process, and at the same time alleviates the destruction of the structure due to volume expansion, improving the cycle characteristics and charging performance of the material.

Description

Technical Field

[0001] [Cross-reference] This application claims priority to a Chinese patent application filed with the China National Intellectual Property Administration on May 27, 2022, with application number 202210586889.0 and invention title "Composite Lithium Storage Material for Lithium-Ion Batteries, Preparation Method Thereof, and Application".

[0002] The present invention relates to the technical field of batteries, and in particular, to a composite lithium storage material for lithium-ion batteries, a preparation method thereof, and an application.

Background Art

[0003] Li 4.2 The theoretical capacity of silicon when forming an Li-Si alloy is up to 4000 mAh / g at maximum, which is much larger than the theoretical capacity of graphite. However, during the alloying process, the volume of silicon expands by 300%, pulverizing the electrode and ultimately degrading the cycle performance of the battery.

[0004] Manufacturing a nanostructured electrode can significantly improve the properties of the silicon negative electrode, because the fracture mechanism changes when the crystal size of the material reaches several tens of nanometers.

[0005] Currently, it is common to obtain nanostructured materials by dispersing silicon in carbon materials by chemical vapor deposition (CVD). However, for silicon-carbon composite materials produced by the CVD method, the forms of Si and C cannot be controlled, so it is difficult to solve the problem of volume expansion and it affects the cycle performance of the battery.

Summary of the Invention

Problems to be Solved by the Invention

[0006] In an embodiment of the present invention, a composite lithium storage material for a lithium-ion battery, a preparation method thereof, and an application are provided. By means of a high-temperature plasma torch, micron-sized silicon powder is vaporized into gaseous silicon, carried by a carrier gas to a condensation region, rapidly cooled, deposited in pores of a porous non-graphitizable carbon material, nucleated in situ, and grown into nanosilicon. The structure of the nanosilicon particles formed by this method is uniform and has high purity. The pores of the porous non-graphitizable carbon material can limit the size of the nanosilicon after deposition and can be uniformly dispersed in the porous non-graphitizable carbon material, reducing the expansion effect and avoiding the problem of poor electrical contact due to pulverization of the electrode. Taking the porous non-graphitizable carbon material of the composite lithium storage material according to the embodiment of the present invention as a matrix, more nanosilicon particles can be deposited in the through pores, so it has a higher compression density, further increases the charge specific capacity of the material, is more advantageous for the insertion and extraction of lithium ions in the charge-discharge process, and at the same time alleviates the structural damage caused by volume expansion and improves the cycle performance and charging performance of the material.

Means for Solving the Problems

[0007] In a first aspect, an embodiment of the present invention provides a composite lithium storage material for a lithium-ion battery. The composite lithium storage material includes a spherical porous non-graphitizable carbon material and nanosilicon grown in situ in pores of the spherical porous non-graphitizable carbon material. The nanosilicon is vaporized from micron-sized silicon powder by a high-frequency plasma processing device and then grows in situ in the pores of the porous non-graphitizable carbon material. The particle size of the nanosilicon is 0.1 nm to 50 nm, and the mass percentage of the nanosilicon in the silicon-non-graphitizable carbon composite material is 1% to 70%.

[0008] Preferably, the average pore diameter of the pores of the spherical porous non-graphitizable carbon material is 0.1 nm to 50 nm, and the particle size of the composite lithium storage material is 1 μm to 100 μm.

[0009] Preferably, the porous graphitization-resistant carbon material is prepared from a graphitization-resistant carbon matrix, and the graphitization-resistant carbon matrix contains one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The micron-sized silicon powder contains one or more of silicon powder by-produced during diamond wire cutting of a silicon material, waste silicon powder generated during the production of organosilicon, or industrial silicon powder.

[0010] In a second aspect, an embodiment of the present invention provides a method for preparing the composite lithium storage material for a lithium-ion battery described in the first aspect above. The preparation method includes: Putting the graphitization-resistant carbon matrix into a hydrothermal reactor for hydrothermal treatment. After taking out the material, washing and filtering the filtrate until it becomes colorless and transparent, and further drying to obtain graphitization-resistant carbon particles. Putting the graphitization-resistant carbon particles into a reaction device, raising the temperature to 700°C to 1300°C, and holding for 0.5 hour to 15 hours to subject the graphitization-resistant carbon particles to carbonization treatment. After taking out the product obtained by the carbonization treatment, pulverizing and sieving to obtain a graphitization-resistant carbon precursor. Putting the graphitization-resistant carbon precursor into the reaction device, raising the temperature to 600°C to 1000°C, and holding for 1 hour to 10 hours. During the holding, introducing a gas source to subject the graphitization-resistant carbon precursor to pore-forming treatment to obtain a spherical porous graphitization-resistant carbon material. Placing the spherical porous graphitization-resistant carbon material in the condensation region of a high-frequency plasma treatment device, placing the micron-sized silicon powder in the high-temperature region, introducing a protective gas into the high-frequency plasma treatment device to replace the air, turning on the plasma generator of the high-frequency plasma treatment device, ionizing the working gas to generate a plasma torch, vaporizing the micron-sized silicon powder to form gaseous silicon, transporting the gaseous silicon to the condensation region by a carrier gas, depositing the gaseous silicon in the pores of the porous graphitization-resistant carbon material, nucleating and growing into nanometer-sized nanosilicon to obtain a composite lithium storage material for a lithium-ion battery. including the particle size of the nano-silicon is 0.1 nm to 50 nm, and the mass percentage of the nano-silicon in the silicon-inhibited graphitizable carbon composite material is 1% to 70%.

[0011] Preferably, the inhibited graphitizable carbon matrix includes one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The micron-sized silicon powder includes one or more of silicon powder by-produced during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organosilicon, or industrial silicon powder. The particle size D50 of the micron-sized silicon powder is 5 μm to 100 μm. The average pore diameter of the pores of the spherical porous inhibited graphitizable carbon material is 0.1 nm to 50 nm. The particle size of the composite lithium storage material is 1 μm to 100 μm.

[0012] Preferably, the conditions of the hydrothermal treatment under pressure are as follows: that is, the pressure is set to 0.1 MPa to 10 MPa, the heating temperature is set to 150 °C to 300 °C, and the heat preservation time is set to 2 hours to 8 hours. The conditions of the non-pressure hydrothermal treatment are as follows: that is, the heating temperature is set to 200 °C to 300 °C, and the heat preservation time is set to 5 hours to 30 hours. The reaction device includes any one of a rotary furnace, a tubular furnace, a bell-type furnace, or a fluidized bed.

[0013] Preferably, the gas source includes any one of oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is 0.5 L / min to 20 L / min. Preferably, the protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m 3 / h to 3 m 3 / h. The operating gas is nitrogen gas or argon gas, and the flow rate of the operating gas is 3 m 3 / h to 8 m 3 / h. The carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m 3 / hour to 1 m 3 / hour, and when generating the plasma torch, the operating voltage of the plasma generator is 100 V to 150 V, and the current is 80 A to 180 A.

[0014] In a third aspect, an embodiment of the present invention provides a negative electrode plate including the composite lithium storage material described in the first aspect.

[0015] In a fourth aspect, an embodiment of the present invention provides a lithium-ion battery including the negative electrode plate described in the third aspect.

Advantages of the Invention

[0016] The composite lithium storage material according to the embodiment of the present invention vaporizes micron-sized silicon powder by a high-temperature plasma torch to form gaseous silicon, which is carried by a carrier gas to a condensation region, rapidly cooled, deposited in pores of a porous graphitizable carbon material, nucleates in situ, and grows into nanosilicon. The structure of the nanosilicon particles formed in this way is uniform and has high purity. The pores of the porous graphitizable carbon material can limit the size of the nanosilicon after deposition and can be uniformly dispersed in the porous graphitizable carbon material, reducing the expansion effect and avoiding the problem of poor electrical contact due to pulverization of the electrode. Using the porous graphitizable carbon material of the composite lithium storage material according to the embodiment of the present invention as a matrix, more nanosilicon particles can be deposited in the through pores, so it has a higher compression density, further increases the charge specific capacity of the material, is more advantageous for the insertion and extraction of lithium ions in the charge and discharge process, and at the same time alleviates the destruction of the structure due to volume expansion, improving the cycle characteristics and charge performance of the material.

Brief Description of the Drawings

[0017] Hereinafter, the technical solutions in the embodiments of the present invention will be described in more detail with reference to the drawings and embodiments.

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0019] Hereinafter, the present invention will be further described with reference to the drawings and specific examples, but it should be understood that these examples are only for explaining the present invention in more detail and are not intended to limit the present invention in any form, that is, they are not intended to limit the protection scope of the present invention.

[0020] The composite lithium storage material for a lithium-ion battery according to an embodiment of the present invention includes a spherical porous graphitizable carbon material and nanosilicon grown in-situ within the pores of the spherical porous graphitizable carbon material. The nanosilicon is vaporized from micron-sized silicon powder by a high-frequency plasma processing apparatus and then grows in-situ within the pores of the porous graphitizable carbon material. The particle size of the nanosilicon is 0.1 nm to 50 nm, and the mass percentage of the nanosilicon in the silicon-graphitizable carbon composite material is 1% to 70%.

[0021] The average pore diameter of the pores of the spherical porous graphitizable carbon material is 0.1 nm to 50 nm, and the particle size of the composite lithium storage material is 1 μm to 100 μm.

[0022] The porous graphitization-resistant carbon material is prepared from a graphitization-resistant carbon matrix, where the graphitization-resistant carbon matrix contains one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The micron-sized silicon powder contains one or more of silicon powder by-produced during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organosilicon, or industrial silicon powder.

[0023] Examples of the present invention provide a method for preparing the above composite lithium storage material for lithium-ion batteries. As shown in FIG. 1, the preparation method includes the following steps.

[0024] In step 110, the graphitization-resistant carbon matrix is placed in a hydrothermal reactor for hydrothermal treatment. After taking out the material, the filtrate is washed and filtered until it becomes colorless and transparent, and then dried to obtain graphitization-resistant carbon particles. Here, the graphitization-resistant carbon matrix contains one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. Specifically, as the hydrothermal treatment, pressurized hydrothermal treatment or non-pressurized hydrothermal treatment can be used. The conditions for pressurized hydrothermal treatment are as follows: that is, the pressure is set to 0.1 MPa to 10 MPa, the heating temperature is set to 150 °C to 300 °C, and the heat preservation time is set to 2 hours to 8 hours. The conditions for non-pressurized hydrothermal treatment are as follows: that is, the heating temperature is set to 200 °C to 300 °C, and the heat preservation time is set to 5 hours to 30 hours.

[0025] In step 120, the graphitization-resistant carbon particles are placed in a reaction device, the temperature is raised to 700 °C to 1300 °C, and heat preservation is carried out for 0.5 hours to 15 hours for carbonization treatment. After pulverization and sieving, a graphitization-resistant carbon precursor is obtained. Here, the reaction device includes any one of a rotary furnace, a tubular furnace, a bell-type furnace, or a fluidized bed.

[0026] In step 130, the graphitizable carbon precursor is placed in a reaction apparatus, the temperature is raised to 600 °C to 1000 °C, and it is kept warm for 1 hour to 10 hours. During the heat preservation, a gas source is introduced to perform pore-forming treatment on the graphitizable carbon precursor, thereby obtaining a spherical porous graphitizable carbon material. Here, the gas source includes any one of oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is 0.5 L / min to 20 L / min.

[0027] In step 140, the spherical porous graphitizable carbon material is placed in the condensation region of a high-frequency plasma processing apparatus, micron-sized silicon powder is placed in the high-temperature region of the high-frequency plasma processing apparatus, a protective gas is introduced into the high-frequency plasma processing apparatus to replace the air, the plasma generator of the high-frequency plasma processing apparatus is turned on, the working gas is ionized to generate a plasma torch, the micron-sized silicon powder is vaporized to become gaseous silicon, the gaseous silicon is transported to the condensation region by a carrier gas, and the gaseous silicon is deposited in the pores of the porous graphitizable carbon material, nucleated, and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for a lithium-ion battery. Here, the operating frequency of the high-frequency plasma processing apparatus is 1 MHz to 300 MHz. The following specific examples of the present invention are realized by using a DLZ-MA-300-B plasma generator as the high-frequency plasma processing apparatus.

[0028] The micron-sized silicon powder includes one or more of silicon powder by-produced during the diamond wire cutting of silicon materials, waste silicon powder generated during the production of organosilicon, or industrial silicon powder. By using the silicon powder by-produced during cutting or the waste silicon powder generated during production, the effects of further saving and cost reduction can be achieved. Moreover, since the micron-sized silicon powder needs to be vaporized in the preparation process, using the silicon powder by-produced during cutting or the waste silicon powder generated during production does not affect the product quality.

[0029] The particle size D50 of the micron-sized silicon powder is 5 μm to 100 μm. The average pore diameter of the pores of the spherical porous non-graphitizable carbon material is 0.1 nm to 50 nm, the particle size of the nanosilicon is 0.1 nm to 50 nm, the mass percentage of the nanosilicon in the silicon-non-graphitizable carbon composite material is 1% to 70%, and the particle size of the composite lithium storage material is 1 μm to 100 μm.

[0030] The protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m 3 / hour to 3 m 3 / hour, The working gas is nitrogen gas or argon gas, and the flow rate of the working gas is 3 m 3 / hour to 8 m 3 / hour, The carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m 3 / hour to 1 m 3 / hour, The operating voltage of the plasma generator when generating the plasma torch is 100 V to 150 V, and the current is 80 A to 180 A.

[0031] The composite lithium storage material of the embodiment of the present invention can be used as a negative electrode active material in a negative electrode plate, and the negative electrode plate can be applied to a lithium ion battery.

[0032] To better understand the technical solution according to the present invention, the preparation process and characteristics of the composite lithium storage material for lithium ion batteries of the present invention will be described below with reference to a plurality of specific examples.

[0033] [Example 1] This example provides a preparation process and a characteristic test of a composite lithium storage material for a lithium ion battery. The specific steps are as follows, that is, 1) Put 200 g of phenol resin into a hydrothermal reactor to perform a hydrothermal reaction. The pressure is 10 Mpa, the temperature is raised to 300 °C, and it is kept warm for 2 hours. Take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain non-graphitizable carbon particles. 2) Put the graphitizable carbon particles into a rotary kiln, raise the temperature to 1300 °C, hold for 0.5 hours, and perform carbonization treatment to obtain a graphitizable carbon precursor. 3) Put the graphitizable carbon precursor into a rotary kiln, raise the temperature to 800 °C, hold for 10 hours, and introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 20 L / min to perform pore-forming treatment on the graphitizable carbon precursor, thereby obtaining a spherical porous graphitizable carbon material. 4) Place the spherical porous graphitizable carbon material in the condensation region of a high-frequency plasma processing apparatus, place the silicon powder by-produced during the diamond wire cutting of a silicon material with a particle size D50 of 5 μm in the high-temperature region, introduce argon gas into the high-frequency plasma processing apparatus to replace the air, and the flow rate of the argon gas is 0.5 m 3 / h. Turn on the plasma generator of the high-frequency plasma processing apparatus, set the operating voltage to 110 V and the current to 100 A, and use argon gas with a flow rate of 3 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region with a plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma processing apparatus with argon gas, which is the carrier gas with a flow rate of 0.1 m 3 / h. Deposit the gaseous silicon in the pores of the spherical porous graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0034] The XRD pattern of the composite lithium storage material for lithium-ion batteries prepared in this example is shown in Figure 3.

[0035] The charge-discharge curve diagram of the composite lithium storage material for lithium-ion batteries prepared in this example is shown in Figure 4.

[0036] Manufacture an electrode using the composite lithium storage material for lithium-ion batteries prepared in this example, assemble and test the battery. Weigh the obtained negative electrode material, carbon black as a conductive additive, and an adhesive (1:1 sodium cellulose and styrene-butadiene rubber) in a ratio of 95:2:3. Prepare a slurry in a beater at room temperature. Apply the prepared slurry uniformly onto a copper foil. After drying in a blower dryer at a temperature of 50 °C for 2 hours, cut it into 8×8 mm electrode sheets, and perform vacuum pumping in a vacuum dryer at a temperature of 100 °C and dry for 10 hours. For battery assembly, immediately transfer the dried electrode sheets into a glove box and prepare them.

[0037] The assembly of the simulated battery is carried out in a glove box containing a high-purity Ar atmosphere, using lithium metal as the counter electrode, and a solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) containing 1 mol / L of LiPF 6 as the electrolyte and assembling it into a battery. Perform a constant current charge-discharge mode test using a charger. The discharge cut-off voltage is 0.005 V, the charge cut-off voltage is 1.5 V, and the charge-discharge test is carried out at a C / 10 current density. The test data are shown in Table 1.

[0038] [Example 2] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows: 1) Put 200 g of phenolic resin into a hydrothermal reactor to carry out a hydrothermal reaction. The pressure is 5 Mpa, raise the temperature to 300 °C, keep it warm for 8 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain non-graphitizable carbon particles. 2) Put the non-graphitizable carbon particles into a rotary furnace, raise the temperature to 700 °C, keep it warm for 15 hours, and perform carbonization treatment to obtain a non-graphitizable carbon precursor. 3) Put the non-graphitizable carbon precursor into a rotary furnace, raise the temperature to 1000 °C, keep it warm for 10 hours, and introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 20 L / min to perform pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) Place the spherical porous graphitization-resistant carbon material in the condensation region of the high-frequency plasma processing apparatus, place the waste silicon powder generated during the production of organic silicon with a particle size D50 of 10 μm in the high-temperature region, introduce nitrogen gas into the high-frequency plasma processing apparatus to replace the air, and the flow rate of the nitrogen gas is 1 m 3 / h, turn on the plasma generator of the high-frequency plasma processing apparatus, set the operating voltage to 105 V and the current to 90 A, and use nitrogen gas with a flow rate of 3.5 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region with the plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma processing apparatus with nitrogen gas, which is the carrier gas with a flow rate of 0.2 m 3 / h. Deposit the gaseous silicon into the pores of the spherical porous graphitization-resistant carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0039] Manufacture an electrode using the composite lithium storage material for lithium-ion batteries prepared in this example, assemble and test the battery, and the specific process is the same as that in Example 1. The test data are shown in Table 1.

[0040] [Example 3] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows, that is, 1) Put 200 g of epoxy resin into a hydrothermal reactor to carry out a hydrothermal reaction. The pressure is 0.5 Mpa, raise the temperature to 300 °C, keep it warm for 8 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain graphitization-resistant carbon particles. 2) Put the graphitization-resistant carbon particles into a rotary furnace, raise the temperature to 1300 °C, keep it warm for 1 hour, and carry out carbonization treatment to obtain a graphitization-resistant carbon precursor. 3) Put the graphitization-resistant carbon precursor into a rotary furnace, raise the temperature to 700 °C, keep it warm for 10 hours, and introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 20 L / min to perform pore-forming treatment on the graphitization-resistant carbon precursor to obtain a spherical porous graphitization-resistant carbon material. 4) Place the spherical porous graphitization-resistant carbon material in the condensation region of the high-frequency plasma processing apparatus, place the silicon powder by-produced during the diamond wire cutting of the silicon material with a particle size D50 of 20 μm in the high-temperature region, introduce argon gas into the high-frequency plasma processing apparatus to replace the air, and the flow rate of the argon gas is 1.5 m 3 / h. Turn on the plasma generator of the high-frequency plasma processing apparatus, set the operating voltage to 110 V and the current to 100 A, and use argon gas with a flow rate of 4 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma processing apparatus by argon gas, which is the carrier gas with a flow rate of 0.3 m 3 / h. Deposit the gaseous silicon into the pores of the spherical porous graphitization-resistant carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0041] Manufacture an electrode using the composite lithium storage material for lithium-ion batteries prepared in this example, assemble and test the battery, and the specific process is the same as that in Example 1. The test data are shown in Table 1.

[0042] [Example 4] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows, that is, 1) Put 200 g of phenolic resin into a hydrothermal reactor for hydrothermal reaction. The pressure is 5 Mpa, raise the temperature to 300 °C, keep it warm for 2 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain graphitization-resistant carbon particles. 2) Put the graphitization-resistant carbon particles into a tubular furnace, raise the temperature to 700 °C, keep it warm for 1 hour, and perform carbonization treatment to obtain a graphitization-resistant carbon precursor. 3) Place the refractory graphitizable carbon precursor in a tubular furnace, raise the temperature to 900 °C, hold for 10 hours, and introduce carbon dioxide gas at a flow rate of 20 L / min to perform pore-forming treatment on the refractory graphitizable carbon precursor, thereby obtaining a spherical porous refractory graphitizable carbon material. 4) Place the spherical porous refractory graphitizable carbon material in the condensation region of a high-frequency plasma treatment apparatus, place the silicon powder by-produced during the diamond wire cutting of the silicon material with a particle size D50 of 30 μm in the high-temperature region, introduce nitrogen gas into the high-frequency plasma treatment apparatus to replace the air, and the flow rate of the nitrogen gas is 2 m 3 / h, turn on the plasma generator of the high-frequency plasma treatment apparatus, set the operating voltage to 115 V and the current to 110 A, and the flow rate is 4.5 m 3 / h of nitrogen gas as the working gas, vaporize the silicon powder placed in the high-temperature region with a plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma treatment apparatus with nitrogen gas as the carrier gas at a flow rate of 0.4 m 3 / h, deposit the gaseous silicon in the pores of the spherical porous refractory graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0043] Manufacture an electrode using the composite lithium storage material for lithium-ion batteries prepared in this example, assemble and test the battery, and the specific process is the same as that in Example 1. The test data is shown in Table 1.

[0044] [Example 5] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows, that is, 1) Put 200 g of phenolic resin into a hydrothermal reactor to perform a hydrothermal reaction. The pressure is 5 Mpa, raise the temperature to 300 °C, hold for 8 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry to obtain refractory graphitizable carbon particles. 2) Put the refractory graphitizable carbon particles into a tubular furnace, raise the temperature to 800 °C, hold for 1 hour, and perform carbonization treatment to obtain a refractory graphitizable carbon precursor. 3) Place the graphitizable carbon precursor into a tubular furnace, raise the temperature to 800 °C, hold for 5 hours, introduce steam at a flow rate of 5 L / min to perform pore-forming treatment on the graphitizable carbon precursor, thereby obtaining a spherical porous graphitizable carbon material. 4) Place the spherical porous graphitizable carbon material in the condensation region of a high-frequency plasma treatment apparatus, place the silicon powder by-produced during the diamond wire cutting of the silicon material with a particle size D50 of 40 μm in the high-temperature region, introduce argon gas into the high-frequency plasma treatment apparatus to displace the air, and the flow rate of the argon gas is 2.5 m 3 / h. Turn on the plasma generator of the high-frequency plasma treatment apparatus, set the operating voltage to 120 V and the current to 120 A, and use argon gas with a flow rate of 5 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma treatment apparatus by argon gas, which is the carrier gas with a flow rate of 0.5 m 3 / h. Deposit the gaseous silicon into the pores of the spherical porous graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0045] Using the composite lithium storage material for lithium-ion batteries prepared in this example, an electrode was manufactured and the battery was assembled and tested. The specific process is the same as that in Example 1. The test data are shown in Table 1.

[0046] [Example 6] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows: 1) Put 200 g of phenolic resin into a hydrothermal reactor to perform a hydrothermal reaction. The pressure is 0.1 Mpa, raise the temperature to 300 °C, hold for 8 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain graphitizable carbon particles. 2) Put the graphitizable carbon particles into a rotary kiln, raise the temperature to 700 °C, keep it warm for 6 hours, and perform carbonization treatment to obtain a graphitizable carbon precursor. 3) Put the graphitizable carbon precursor into a rotary kiln, raise the temperature to 800 °C, keep it warm for 10 hours, and introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 5 L / min to perform pore-forming treatment on the graphitizable carbon precursor, thereby obtaining a spherical porous graphitizable carbon material. 4) Place the spherical porous graphitizable carbon material in the condensation region of a high-frequency plasma processing apparatus, place the silicon powder by-produced during the diamond wire cutting of a silicon material with a particle size D50 of 50 μm in the high-temperature region, introduce argon gas into the high-frequency plasma processing apparatus to replace the air, and the flow rate of the argon gas is 3 m 3 / h, turn on the plasma generator of the high-frequency plasma processing apparatus, set the operating voltage to 125 V and the current to 130 A, and use argon gas with a flow rate of 5.5 m 3 / h as the working gas, vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma processing apparatus by argon gas, which is the carrier gas with a flow rate of 0.6 m 3 / h, deposit the gaseous silicon in the pores of the spherical porous graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0047] Use the composite lithium storage material for lithium-ion batteries prepared in this example to manufacture electrodes, assemble and test the batteries, and the specific process is the same as that in Example 1. The test data are shown in Table 1.

[0048] [Example 7] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows, that is, 1) Take a total of 200 g of starch and polyvinylidene fluoride, put them into a hydrothermal reactor, and perform a hydrothermal reaction. The pressure is 5 Mpa, raise the temperature to 300 °C, keep it warm for 8 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain non-graphitizable carbon particles. 2) Put the non-graphitizable carbon particles into a rotary furnace, raise the temperature to 700 °C, keep it warm for 1 hour, and perform carbonization treatment to obtain a non-graphitizable carbon precursor. 3) Put the non-graphitizable carbon precursor into a rotary furnace, raise the temperature to 1000 °C, keep it warm for 10 hours, and introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 5 L / min to perform pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) Place the spherical porous non-graphitizable carbon material in the condensation region of a high-frequency plasma treatment device, place the silicon powder by-produced during the diamond wire cutting of a silicon material with a particle size D50 of 60 μm in the high-temperature region, introduce argon gas into the high-frequency plasma treatment device to replace the air, and the flow rate of the argon gas is 3 m 3 / h. Turn on the plasma generator of the high-frequency plasma treatment device, set the operating voltage to 130 V and the current to 140 A, and use argon gas with a flow rate of 6 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region with the plasma torch generated by the ionization of the working gas to form gaseous silicon, and transport the gaseous silicon to the condensation region of the high-frequency plasma treatment device with argon gas, which is the carrier gas with a flow rate of 0.7 m 3 / h. Deposit the gaseous silicon in the pores of the spherical porous non-graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0049] Use the composite lithium storage material for lithium-ion batteries prepared in this example to manufacture an electrode, assemble and test the battery. The specific process is the same as that in Example 1. The test data are shown in Table 1.

[0050] [Example 8] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows: 1) Take a total of 200 g of starch and polyvinylidene fluoride, put them into a hydrothermal reactor for hydrothermal reaction, with a pressure of 5 Mpa, raise the temperature to 300 °C, keep warm for 6 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry to obtain non-graphitizable carbon particles. 2) Put the non-graphitizable carbon particles into a rotary furnace, raise the temperature to 700 °C, keep warm for 5 hours, and perform carbonization treatment to obtain a non-graphitizable carbon precursor. 3) Put the non-graphitizable carbon precursor into a rotary furnace, raise the temperature to 900 °C, keep warm for 5 hours, introduce a mixed gas source of carbon dioxide and water vapor at a flow rate of 5 L / min to perform pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) Place the spherical porous non-graphitizable carbon material in the condensation region of a high-frequency plasma treatment device, place the silicon powder by-produced during the diamond wire cutting of a silicon material with a particle size D50 of 70 μm in the high-temperature region, introduce nitrogen gas into the high-frequency plasma treatment device to replace the air, and the flow rate of the nitrogen gas is 3 m 3 / h. Turn on the plasma generator of the high-frequency plasma treatment device, set the operating voltage to 135 V and the current to 150 A, use nitrogen gas with a flow rate of 6.5 m 3 / h as the working gas, vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to form gaseous silicon, transport the gaseous silicon to the condensation region of the high-frequency plasma treatment device by nitrogen gas, which is the carrier gas with a flow rate of 0.8 m 3 / h, deposit the gaseous silicon into the pores of the spherical porous non-graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0051] Use the composite lithium storage material for lithium-ion batteries prepared in this example to manufacture electrodes, assemble and test the batteries. The specific process is the same as that in Example 1. The test data are shown in Table 1.

[0052] [Example 9] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows: 1) Put 200 g of glucose into a hydrothermal reactor for hydrothermal reaction. The pressure is 2 Mpa, the temperature is raised to 300 °C, and it is kept warm for 8 hours. Take out the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Put the non-graphitizable carbon particles into a rotary furnace, raise the temperature to 900 °C, and keep warm for 1 hour for carbonization treatment to obtain a non-graphitizable carbon precursor. 3) Put the non-graphitizable carbon precursor into a rotary furnace, raise the temperature to 1000 °C, and keep warm for 10 hours. Introduce water vapor at a flow rate of 5 L / min to perform pore-forming treatment on the non-graphitizable carbon precursor to obtain a spherical porous non-graphitizable carbon material. 4) Place the spherical porous non-graphitizable carbon material in the condensation region of a high-frequency plasma treatment device, place the silicon powder by-produced during the diamond wire cutting of a silicon material with a particle size D50 of 80 μm in the high-temperature region, introduce nitrogen gas into the high-frequency plasma treatment device to replace the air. The flow rate of the nitrogen gas is 3 m 3 / h. Turn on the plasma generator of the high-frequency plasma treatment device, set the operating voltage to 140 V and the current to 160 A. Use nitrogen gas with a flow rate of 7 m 3 / h as the working gas. Vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to form gaseous silicon. Transport the gaseous silicon to the condensation region of the high-frequency plasma treatment device by nitrogen gas, which is the carrier gas with a flow rate of 0.9 m 3 / h. Deposit the gaseous silicon into the pores of the spherical porous non-graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0053] Use the composite lithium storage material for lithium-ion batteries prepared in this example to manufacture an electrode, assemble and test the battery. The specific process is the same as that in Example 1. The test data is shown in Table 1.

[0054] [Example 10] This example provides a preparation process and property test of a composite lithium storage material for lithium-ion batteries. The specific steps are as follows: 1) Put 200 g of glucose into a hydrothermal reactor for hydrothermal reaction. The pressure is 5 Mpa, raise the temperature to 300 °C, keep it warm for 6 hours, take out the material, wash and filter the filtrate until it becomes colorless and transparent, and further dry it to obtain non-graphitizable carbon particles. 2) Put the non-graphitizable carbon particles into a rotary furnace, raise the temperature to 900 °C, keep it warm for 1 hour, and perform carbonization treatment to obtain a non-graphitizable carbon precursor. 3) Put the non-graphitizable carbon precursor into a rotary furnace, raise the temperature to 900 °C, keep it warm for 5 hours, introduce steam at a flow rate of 5 L / min to perform pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) Place the spherical porous non-graphitizable carbon material in the condensation region of a high-frequency plasma treatment device, place the silicon powder by-produced during the diamond wire cutting of the silicon material with a particle size D50 of 90 μm in the high-temperature region, introduce argon gas into the high-frequency plasma treatment device to replace the air, and the flow rate of the argon gas is 3 m 3 / h. Turn on the plasma generator of the high-frequency plasma treatment device, set the operating voltage to 150 V and the current to 180 A, use argon gas with a flow rate of 8 m 3 / h as the working gas, vaporize the silicon powder placed in the high-temperature region by the plasma torch generated by the ionization of the working gas to become gaseous silicon, transport the gaseous silicon to the condensation region of the high-frequency plasma treatment device by argon gas, which is the carrier gas with a flow rate of 1 m 3 / h, deposit the gaseous silicon in the pores of the spherical porous non-graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0055] An electrode is manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery is assembled and tested. The specific process is the same as that in Example 1. The test data are shown in Table 1.

[0056] To better explain the effects of the embodiments of the present invention, Comparative Example 1 is compared with the above embodiments.

[0057] [Comparative Example 1] This comparative example provides a preparation method and performance test of a conventional silicon-carbon composite material. The specific steps are as follows: 1) 200 g of nano-silicon and 500 g of phenolic resin powder are put into a hydrothermal reactor for hydrothermal treatment. The pressure is set at 5 Mpa, the temperature is raised to 300 °C, and it is kept warm for 8 hours. Then the material is taken out, and the filtrate is washed and filtered until it becomes colorless and transparent, and then dried to obtain a spherical silicon-containing carbon precursor. 2) The spherical silicon-containing carbon precursor is put into a rotary furnace, heated to 900 °C at a rate of 3 °C / min, and carbonized by keeping it warm for 6 hours in a nitrogen gas atmosphere to obtain a silicon-carbon composite material.

[0058] An electrode is manufactured using the silicon-carbon composite material prepared in this comparative example, and the battery is assembled and tested. The specific process is the same as that in Example 1. The test data are shown in Table 1.

[0059] Electrodes are manufactured using the composite lithium storage materials for lithium-ion batteries prepared in Examples 1 to 10 and the silicon-carbon composite material prepared in Comparative Example 1, the batteries are assembled, and their electrochemical properties, charge specific capacity, and Coulomb efficiency of the first cycle are measured and evaluated. The test data are shown in Table 1.

[0060]

Table 1

[0061] From the comparison between Comparative Example 1 and Examples 1 to 10, it can be seen that the charge specific capacity and Coulomb efficiency of the first cycle of the batteries in Examples 1 to 10 of the present invention are superior to those of Comparative Example 1, indicating that the batteries in Examples 1 to 10 of the present invention have better cycle characteristics and charging performance. This is because in the structure of the composite lithium storage material according to the examples of the present invention, a porous graphitizable carbon material is used as the matrix, and more nanosilicon particles can be deposited in the through pores. Therefore, it has a higher compression density, further increases the charge specific capacity of the material, is more advantageous for the insertion and desorption of lithium ions in the charge-discharge process, and at the same time alleviates the structural damage caused by volume expansion, improving the cycle characteristics and charging performance of the material. At the same time, the present invention can further improve the specific capacity of the material and the Coulomb efficiency of the first cycle by adjusting the flow rate of the working gas, the flow rate of the carrier gas, the operating voltage and current of the plasma generator. The present invention can control the flow rates of the working gas and the carrier gas to uniformly deposit gaseous silicon in the pores of the porous graphitizable carbon material. When the flow rates of the working gas and the carrier gas are too high, the gaseous silicon is unevenly deposited in the porous carbon material and directly deposited on its surface, avoiding affecting the performance of the battery.

[0062] In the above specific embodiments, the object, technical solution and beneficial effects of the present invention are further described in detail. The above are only the specific embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0063] [Appendix] [Appendix 1] A composite lithium storage material for a lithium ion battery, comprising: The composite lithium storage material includes a spherical porous graphitizable carbon material and nanosilicon grown in situ in the pores of the spherical porous graphitizable carbon material. The nano-silicon is vaporized from micron-sized silicon powder by a high-frequency plasma processing apparatus and then grows in-situ within the pores of the porous graphitizable carbon material. The particle size of the nano-silicon is 0.1 nm to 50 nm, and the mass percentage of the nano-silicon in the silicon-graphitizable carbon composite material is 1% to 70%. A composite lithium storage material, characterized in that.

[0064] [Appendix 2] The average pore diameter of the pores of the spherical porous graphitizable carbon material is 0.1 nm to 50 nm, and the particle size of the composite lithium storage material is 1 μm to 100 μm. The composite lithium storage material according to Appendix 1, characterized in that.

[0065] [Appendix 3] The porous graphitizable carbon material is prepared from a graphitizable carbon matrix, and the graphitizable carbon matrix contains one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The micron-sized silicon powder contains one or more of silicon powder by-produced during diamond wire cutting of a silicon material, waste silicon powder generated during the production of organosilicon, or industrial silicon powder. The composite lithium storage material according to Appendix 1, characterized in that.

[0066] [Appendix 4] A method for preparing a composite lithium storage material for a lithium-ion battery according to any one of Appendices 1 to 3, Put the graphitizable carbon matrix into a hydrothermal reactor for hydrothermal treatment. After taking out the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain graphitizable carbon particles. Put the graphitization-resistant carbon particles into a reactor, raise the temperature to 700 °C to 1300 °C, keep the temperature for 0.5 hours to 15 hours, subject the graphitization-resistant carbon particles to carbonization treatment, take out the product obtained by the carbonization treatment, and then pulverize and perform sieving to obtain a graphitization-resistant carbon precursor; Put the graphitization-resistant carbon precursor into the reactor, raise the temperature to 600 °C to 1000 °C, keep the temperature for 1 hour to 10 hours, introduce a gas source during the temperature holding to subject the graphitization-resistant carbon precursor to pore-forming treatment, thereby obtaining a spherical porous graphitization-resistant carbon material; Place the spherical porous graphitization-resistant carbon material in the condensation region of a high-frequency plasma processing apparatus, place micron-sized silicon powder in the high-temperature region of the high-frequency plasma processing apparatus, introduce a protective gas into the high-frequency plasma processing apparatus to replace the air, turn on the plasma generator of the high-frequency plasma processing apparatus, ionize the working gas to generate a plasma torch, vaporize the micron-sized silicon powder to form gaseous silicon, transport the gaseous silicon to the condensation region by a carrier gas, deposit the gaseous silicon in the pores of the porous graphitization-resistant carbon material, nucleate and grow into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for a lithium-ion battery; including the particle size of the nanosilicon is 0.1 nm to 50 nm, and the mass percentage of the nanosilicon in the silicon-graphitization-resistant carbon composite material is 1% to 70%. A preparation method characterized by the above.

[0067] [Appendix 5] The graphitization-resistant carbon matrix contains one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenol resin, or polyvinyl chloride. The micron-sized silicon powder contains one or more of silicon powder by-produced during diamond wire cutting of a silicon material, waste silicon powder generated during the production of organosilicon, or industrial silicon powder. The particle size D50 of the micron-sized silicon powder is 5 μm to 100 μm. The average pore diameter of the spherical porous non-graphitizable carbon material is 0.1 nm to 50 nm, the particle size of the composite lithium storage material is 1 μm to 100 μm, The preparation method according to Supplementary Note 4, characterized by the above.

[0068] [Supplementary Note 6] The hydrothermal treatment is either a pressurized hydrothermal treatment or a non-pressurized hydrothermal treatment, the conditions of the pressurized hydrothermal treatment are as follows, that is, the pressure is set to 0.1 MPa to 10 MPa, the heating temperature is set to 150 °C to 300 °C, and the heat preservation time is set to 2 hours to 8 hours, the conditions of the non-pressurized hydrothermal treatment are as follows, that is, the heating temperature is set to 200 °C to 300 °C, and the heat preservation time is set to 5 hours to 30 hours, The reaction device includes any one of a rotary furnace, a tubular furnace, a bell-type furnace, or a fluidized bed, The preparation method according to Supplementary Note 4, characterized by the above.

[0069] [Supplementary Note 7] The gas source includes any one of oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is 0.5 L / min to 20 L / min, The preparation method according to Supplementary Note 4, characterized by the above.

[0070] [Supplementary Note 8] The protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m 3 / hour to 3 m 3 / hour, the working gas is nitrogen gas or argon gas, and the flow rate of the working gas is 3 m 3 / hour to 8 m 3 / hour, the carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m 3 / hour to 1 m 3 / hour, When the plasma torch is generated, the operating voltage of the plasma generator is 100 V to 150 V, and the current is 80 A to 180 A, The preparation method according to Supplementary Note 4, characterized by the above.

[0071] [Supplementary Note 9] A negative electrode tab, comprising a composite lithium storage material described in any one of Supplementary Notes 1 to 3. Characterized by the above.

[0072] [Supplementary Note 10] A lithium ion battery, comprising the negative electrode tab described in Supplementary Note 9. Characterized by the above.

Claims

1. A composite lithium storage material for a lithium-ion battery, wherein the composite lithium storage material includes a spherical porous graphitizable carbon material and nano-silicon grown in-situ within the pores of the spherical porous graphitizable carbon material, wherein the nano-silicon is vaporized from micron-sized silicon powder by a high-frequency plasma processing apparatus and then grows in-situ within the pores of the porous graphitizable carbon material, wherein the particle size of the nano-silicon is 0.1 nm to 50 nm, and the mass percentage of the nano-silicon in the silicon-graphitizable carbon composite material is 1% to 70%, characterized in that it is a composite lithium storage material.

2. The average pore diameter of the pores of the spherical porous graphitizable carbon material is 0.1 nm to 50 nm, and the particle size of the composite lithium storage material is 1 μm to 100 μm, characterized in that it is the composite lithium storage material according to Claim 1.

3. The porous graphitizable carbon material is prepared from a graphitizable carbon matrix, and the graphitizable carbon matrix includes one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin or polyvinyl chloride, wherein the micron-sized silicon powder includes one or more of silicon powder by-produced during diamond wire cutting of a silicon material, waste silicon powder generated during the production of organosilicon, or industrial silicon powder, characterized in that it is the composite lithium storage material according to Claim 1.

4. A method for preparing the composite lithium storage material for a lithium-ion battery according to any one of Claims 1 to 3, putting the graphitizable carbon matrix into a hydrothermal reactor for hydrothermal treatment, taking out the material, washing and filtering the filtrate until it becomes colorless and transparent, and further drying to obtain graphitizable carbon particles, putting the graphitizable carbon particles into a reaction apparatus, raising the temperature to 700 °C to 1300 °C, holding the temperature for 0.5 hour to 15 hours, subjecting the graphitizable carbon particles to carbonization treatment, taking out the product obtained by the carbonization treatment, and then pulverizing and sieving to obtain a graphitizable carbon precursor, putting the graphitizable carbon precursor into the reaction apparatus, raising the temperature to 600 °C to 1000 °C, holding the temperature for 1 hour to 10 hours, introducing a gas source during the holding to subject the graphitizable carbon precursor to pore-forming treatment to obtain a spherical porous graphitizable carbon material, Place a spherical porous graphitizable carbon material in the condensation region of a high-frequency plasma processing apparatus, place micron-sized silicon powder in the high-temperature region of the high-frequency plasma processing apparatus, introduce a protective gas into the high-frequency plasma processing apparatus to replace the air, turn on the plasma generator of the high-frequency plasma processing apparatus, the working gas is ionized to generate a plasma torch, vaporize the micron-sized silicon powder to form gaseous silicon, transport the gaseous silicon to the condensation region by a carrier gas, deposit the gaseous silicon in the pores of the porous graphitizable carbon material, nucleate and grow into nanometer-sized nanosilicon to obtain a composite lithium storage material for a lithium-ion battery, and including the particle size of the nanosilicon is 0.1 nm to 50 nm, and the mass percentage of the nanosilicon in the silicon-graphitizable carbon composite material is 1% to 70%. A preparation method characterized by this.

5. The graphitizable carbon matrix includes one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride, the micron-sized silicon powder includes one or more of silicon powder by-produced during diamond wire cutting of a silicon material, waste silicon powder generated during the production of organosilicon, or industrial silicon powder, and the particle size D50 of the micron-sized silicon powder is 5 μm to 100 μm, the average pore diameter of the pores of the spherical porous graphitizable carbon material is 0.1 nm to 50 nm, the particle size of the composite lithium storage material is 1 μm to 100 μm. The preparation method according to claim 4, characterized by this.

6. The hydrothermal treatment is a pressurized hydrothermal treatment or a non-pressurized hydrothermal treatment, the conditions of the pressurized hydrothermal treatment are as follows, that is, the pressure is set to 0.1 MPa to 10 MPa, the heating temperature is set to 150 °C to 300 °C, and the heat preservation time is set to 2 hours to 8 hours, the conditions of the non-pressurized hydrothermal treatment are as follows, that is, the heating temperature is set to 200 °C to 300 °C, and the heat preservation time is set to 5 hours to 30 hours, the reaction device includes any one of a rotary furnace, a tubular furnace, a bell-type furnace, or a fluidized bed. The preparation method according to claim 4, characterized by this.

7. The gas source includes any one of oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is 0.5 L / min to 20 L / min. The preparation method according to claim 4, characterized in that...

8. The protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m ３ / hour to 3 m ３ / hour, and The operating gas is nitrogen gas or argon gas, and the flow rate of the operating gas is 3 m ３ / hour to 8 m ３ / hour, and The carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m ３ / hour to 1 m ３ / hour, and When generating the plasma torch, the operating voltage of the plasma generator is 100V to 150V, and the current is 80A to 180A. The preparation method according to claim 4, characterized in that...

9. Including the composite lithium storage material according to any one of claims 1 to 3. The negative electrode tab, characterized in that...

10. Including the negative electrode tab according to claim 9. The lithium ion battery, characterized in that...

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