Method for preparing composite lithium storage materials for lithium-ion batteries

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 the Chinese patent application filed with the Chinese National Intellectual Property Office on May 27, 2022, with application number 202210586889.0, and titled "Composite Lithium Storage Material for Lithium-Ion Batteries, Method for Preparation of the Same, and its Application."

[0002] This invention relates to the technology of batteries, and more particularly to composite lithium storage materials for lithium-ion batteries, methods for preparing the same, and applications. [Background technology]

[0003] Li 4.2 The theoretical capacity of silicon when forming Si alloys is up to 4000 mAh / g, which is far greater than the theoretical capacity of graphite. However, during the alloying process, the volume of silicon expands by 300%, causing the electrodes to pulverize and ultimately degrading the battery's cycle performance.

[0004] By fabricating nanostructured electrodes, the properties of silicon anodes can be significantly improved because the fracture mechanism changes when the crystal size of the material reaches tens of nanometers.

[0005] Currently, nanostructured materials are commonly obtained by dispersing silicon in carbon materials using chemical vapor deposition (CVD). However, because the morphology of Si and C cannot be controlled in silicon-carbon composite materials produced by CVD, it is difficult to solve the problem of material expansion, which affects the cycle characteristics of batteries. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In embodiments of the present invention, a composite lithium storage material for lithium-ion batteries, a method for preparing the same, and its applications are provided. Micron-sized silicon powder is vaporized by a high-temperature plasma torch to become gaseous silicon, which is then transported to a condensation region by a carrier gas, rapidly cooled, and deposited in the pores of a porous, non-graphitizable carbon material, where it undergoes nucleation and grows into nanosilicon. The nanosilicon particles formed by this method have a uniform structure and high purity. The pores of the porous, non-graphitizable carbon material limit the size of the nanosilicon after deposition, allowing for uniform dispersion within the porous, non-graphitizable carbon material, reducing the expansion effect, and avoiding the problem of poor electrical contact due to electrode pulverization. In the composite lithium storage material according to embodiments of the present invention, a porous, non-graphitizable carbon material is used as the matrix, allowing for the deposition of more nanosilicon particles in the perforated pores. This results in a higher compressive density, further increasing the material's charge-to-charge capacity, which is more advantageous for lithium ion insertion and removal during the charge-discharge process, while simultaneously mitigating structural damage due to expansion and improving the material's cycle characteristics and charging performance. [Means for solving the problem]

[0007] In a first embodiment, an example of the present invention provides a composite lithium storage material for lithium-ion batteries. The composite lithium storage material comprises a spherical porous non-graphitizable carbon material and nanosilicon grown in situ within the 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 within 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 size 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 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, and the preparation method includes: Put the graphitization-resistant 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 graphitization-resistant carbon particles. Put the graphitization-resistant carbon particles into a reaction device, raise the temperature to 700 °C to 1300 °C, keep the temperature for 0.5 hours to 15 hours to perform carbonization treatment on the graphitization-resistant carbon particles. After taking out the product obtained by the carbonization treatment, pulverize and perform sieving to obtain a graphitization-resistant carbon precursor. Put the graphitization-resistant carbon precursor into the reaction device, raise the temperature to 600 °C to 1000 °C, keep the temperature for 1 hour to 10 hours, and introduce a gas source during the temperature holding to perform pore-forming treatment on the graphitization-resistant carbon precursor to obtain a spherical porous graphitization-resistant carbon material. Place the spherical porous graphitization-resistant carbon material in the condensation region of a high-frequency plasma treatment device, place the micron-sized silicon powder in the high-temperature region, introduce a protective gas into the high-frequency plasma treatment device to replace the air, turn on the plasma generator of the high-frequency plasma treatment device, ionize the working gas to generate a plasma torch, vaporize the micron-sized silicon powder to become 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 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 / 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 m³. 3 / hour ~ 1m 3 / time, When generating the plasma torch, the operating voltage of the plasma generator is 100V to 150V, and the current is 80A to 180A.

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

[0015] In a fourth embodiment, an embodiment of the present invention provides a lithium-ion battery comprising the negative electrode piece described in the third embodiment. [Effects of the Invention]

[0016] In the composite lithium storage material according to the embodiment of the present invention, micron-sized silicon powder is vaporized by a high-temperature plasma torch to become gaseous silicon, which is then transported to a condensation region by a carrier gas, rapidly cooled, deposited in the pores of a porous, non-graphitizable carbon material, where it nucleates in situ and grows into nanosilicon. The nanosilicon particles formed by this method have a uniform and high purity structure, and the pores of the porous, non-graphitizable carbon material limit the size of the deposited nanosilicon, allowing for uniform dispersion within the porous, non-graphitizable carbon material, reducing the expansion effect, and avoiding the problem of poor electrical contact due to electrode pulverization. In the composite lithium storage material according to the embodiment of the present invention, a porous, non-graphitizable carbon material is used as the matrix, allowing for the deposition of more nanosilicon particles in the perforated pores, resulting in a higher compressive density, further increasing the material's charge-to-charge capacity, which is more advantageous for lithium ion insertion and removal during the charge-discharge process, while simultaneously mitigating structural damage due to body expansion and improving the material's cycle characteristics and charging performance. [Brief explanation of the drawing]

[0017] The technical proposal in the embodiments of the present invention will be described in more detail below with reference to the drawings and examples.

[0018] [Figure 1] This is a flowchart for preparing a composite lithium storage material for lithium-ion batteries according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of the composite lithium storage material for lithium-ion batteries prepared in Example 1 of the present invention. [Figure 3] This is the X-ray diffraction (XRD) pattern of the composite lithium storage material for lithium-ion batteries prepared in Example 1 of the present invention. [Figure 4] This is a charge-discharge curve diagram of a composite lithium storage material for lithium-ion batteries prepared in Example 1 of the present invention. [Modes for carrying out the invention]

[0019] The present invention will be further described below with reference to the drawings and specific embodiments, but these embodiments are merely for the purpose of illustrating the present invention in more detail and should be understood as not intended to limit the present invention in any way, that is, they are not intended to limit the scope of protection of the present invention.

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

[0021] The average pore size of spherical porous, non-graphitizable carbon materials is 0.1 nm to 50 nm, while the particle size of composite lithium storage materials is 1 μm to 100 μm.

[0022] Porous, non-graphitizable carbon materials are prepared from a non-graphitizable carbon matrix, where the non-graphitizable carbon matrix contains 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 the following: silicon powder produced as a by-product during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organic silicon, or industrial silicon powder.

[0023] An embodiment of the present invention provides a method for preparing the above-mentioned composite lithium storage material for lithium-ion batteries, and as shown in Figure 1, the preparation method includes the following steps.

[0024] In step 110, the non-graphitizable carbon matrix is ​​placed in a hydrothermal reactor and subjected to hydrothermal treatment. After removing the material, the filtrate is washed and filtered until it becomes colorless and transparent, and then dried to obtain non-graphitizable carbon particles. Here, the non-graphitizable carbon matrix includes 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: pressure set to 0.1 MPa to 10 MPa, heating temperature set to 150°C to 300°C, and holding time set to 2 to 8 hours. The conditions for non-pressurized hydrothermal treatment are as follows: the heating temperature is set to 200°C to 300°C, and the holding time is set to 5 to 30 hours.

[0025] In step 120, non-graphitizable carbon particles are placed in a reaction apparatus, the temperature is raised to 700°C to 1300°C, and the temperature is maintained for 0.5 to 15 hours to perform carbonization treatment, followed by pulverization and sieving to obtain a non-graphitizable carbon precursor. Here, the reaction apparatus includes either a rotary furnace, a tubular furnace, a bell-type furnace, or a fluidized bed.

[0026] In step 130, a non-graphitizable carbon precursor is placed in a reaction apparatus, the temperature is raised to 600°C to 1000°C, and the temperature is maintained for 1 to 10 hours. During this period, a gas source is introduced to create pores in the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. Here, the gas source contains either oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is between 0.5 L / min and 20 L / min.

[0027] In step 140, a spherical porous non-graphitizable carbon material is placed in the condensation region of the 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 into gaseous silicon, the gaseous silicon is carried to the condensation region by a carrier gas, the gaseous silicon is deposited in the pores of the porous non-graphitizable carbon material, nucleation occurs and it grows into nanometer-sized nanosilicon, and a composite lithium storage material for lithium-ion batteries is obtained. Here, the operating frequency of the high-frequency plasma processing apparatus is 1 MHz to 300 MHz. The following specific embodiments 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 the following: silicon powder produced as a by-product during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organic silicon, or industrial silicon powder. By using silicon powder produced as a by-product during cutting or waste silicon powder generated during production, further savings and cost reductions can be achieved. Furthermore, since the micron-sized silicon powder needs to be vaporized during the preparation process, using silicon powder produced as a by-product during cutting or waste silicon powder generated during production does not affect the quality of the product.

[0029] The particle size D50 of micron-sized silicon powder is 5 μm to 100 μm. The average pore diameter of the pores of the spherical porous graphitization-resistant 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-graphitization-resistant 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 / h to 3 m 3 / h, The working gas is nitrogen gas or argon gas, and the flow rate of the working 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 / h to 1 m 3 / h, 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] In order 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: 1) Put 200 g of phenolic resin into a hydrothermal reactor for hydrothermal reaction. The pressure is 10 Mpa, the temperature is raised to 300 °C, and it is kept warm for 2 hours. Then 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) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 1300°C, maintain the temperature for 0.5 hours, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 800°C, and the temperature is maintained for 10 hours. A mixed gas source of carbon dioxide and water vapor is then introduced at a flow rate of 20 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 5 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 0.5 m³. 3 The setting is / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 110V, the current to 100A, and the flow rate is 3m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.1 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0034] Figure 3 shows the XRD pattern of the composite lithium storage material for lithium-ion batteries prepared in this embodiment.

[0035] Figure 4 shows the charge-discharge curves of the composite lithium storage material for lithium-ion batteries prepared in this embodiment.

[0036] Using the lithium-ion battery composite lithium storage material prepared in this embodiment, electrodes are manufactured, and the battery is assembled and tested. The obtained negative electrode material, the conductive additive carbon black, and the adhesive (1:1 sodium cellulose and styrene-butadiene rubber) were weighed in a ratio of 95:2:3. A slurry was prepared in a beater at room temperature. The prepared slurry was uniformly applied to the copper foil. After drying in a forced-air dryer at 50°C for 2 hours, it was cut into 8 x 8 mm electrode pieces and dried in a vacuum dryer at 100°C for 10 hours. For battery assembly, the dried electrode pieces were immediately transferred to a glove box and set aside.

[0037] The simulated battery was assembled in a glove box containing a high-purity Ar atmosphere. A lithium metal counter electrode was used, and an ethylene carbonate (EC) / dimethyl carbonate (DMC) solution containing 1 mol / L LiPF6 was used as the electrolyte. Constant current charge-discharge mode tests were performed using a charge / discharge device. The discharge termination voltage was 0.005V, the charge termination voltage was 1.5V, and the charge / discharge tests were performed at a C / 10 current density. The test data are shown in Table 1.

[0038] [Example 2] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of phenolic resin in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 5 MPa. Raise the temperature to 300°C and maintain the temperature for 8 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 700°C, maintain the temperature for 15 hours, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 1000°C, and the temperature is maintained for 10 hours. A mixed gas source of carbon dioxide and water vapor is then introduced at a flow rate of 20 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, waste silicon powder generated during the production of organosilicon with a particle size D50 of 10 μm is placed in the high-temperature region, nitrogen gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the nitrogen gas flow rate is 1 m³ 3 The setting is / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 105V, the current to 90A, and the flow rate is 3.5m / hour. 3 Nitrogen gas is used as the working gas, and the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.2 m³. 3 Nitrogen gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited within the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries.

[0039] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0040] [Example 3] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of epoxy resin in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 0.5 MPa. Raise the temperature to 300°C and maintain the temperature for 8 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 1300°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 700°C, and the temperature is maintained for 10 hours. A mixed gas source of carbon dioxide and water vapor is then introduced at a flow rate of 20 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 20 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 1.5 m³. 3 The system is set to a frequency of 110V, a current of 100A, and a flow rate of 4m / hour. The plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 110V, the current to 100A, and the flow rate is 4m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.3 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0041] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0042] [Example 4] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of phenolic resin in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 5 MPa. Raise the temperature to 300°C and maintain the temperature for 2 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles into a tubular furnace, raise the temperature to 700°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a tubular furnace, the temperature is raised to 900°C, and the temperature is maintained for 10 hours. Then, carbon dioxide gas is introduced at a flow rate of 20 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 30 μm, is placed in the high-temperature region, nitrogen gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the nitrogen gas flow rate is 2 m³ 3 The parameters are set to / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 115V, the current to 110A, and the flow rate to 4.5m / hour. 3 Nitrogen gas is used as the working gas, and the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.4 m³. 3 Nitrogen gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited within the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries.

[0043] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0044] [Example 5] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of phenolic resin in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 5 MPa. Raise the temperature to 300°C and maintain the temperature for 8 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles into a tubular furnace, raise the temperature to 800°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a tubular furnace, the temperature is raised to 800°C, and the temperature is maintained for 5 hours. Steam is then introduced at a flow rate of 5 L / min to create pores in the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 40 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 2.5 m³. 3 The system is set to 120V / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 120V, the current to 120A, and the flow rate is 5m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.5 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0045] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0046] [Example 6] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of phenolic resin in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 0.1 MPa. Raise the temperature to 300°C and maintain the temperature for 8 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 700°C, maintain the temperature for 6 hours, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 800°C, and the temperature is maintained for 10 hours. A mixed gas source of carbon dioxide and water vapor is then introduced at a flow rate of 5 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 50 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 3 m³. 3 The setting is / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 125V, the current to 130A, and the flow rate is 5.5m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.6 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0047] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0048] [Example 7] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Take a total of 200g of starch and polyvinylidene fluoride and place them in a hydrothermal reactor to carry out a hydrothermal reaction at a pressure of 5 MPa, raise the temperature to 300°C and maintain the temperature for 8 hours, remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 700°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 1000°C, and the temperature is maintained for 10 hours. A mixed gas source of carbon dioxide and water vapor is introduced at a flow rate of 5 L / min to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 60 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 3 m³. 3 The system is set to 130V / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 130V, the current to 140A, and the flow rate is 6m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.7 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

[0049] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0050] [Example 8] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Take a total of 200g of starch and polyvinylidene fluoride and place them in a hydrothermal reactor to carry out a hydrothermal reaction at a pressure of 5 MPa, raise the temperature to 300°C and maintain the temperature for 6 hours, remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 700°C, maintain the temperature for 5 hours, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 900°C, and the temperature is maintained for 5 hours. A mixed gas source of carbon dioxide and water vapor is introduced at a flow rate of 5 L / min to perform a pore formation treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 70 μm, is placed in the high-temperature region, nitrogen gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the nitrogen gas flow rate is 3 m³ 3 The setting is / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 135V, the current to 150A, and the flow rate is 6.5m / hour. 3 Nitrogen gas is used as the working gas, and the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.8 m³. 3 Nitrogen gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited within the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries.

[0051] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0052] [Example 9] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of glucose in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 2 MPa. Raise the temperature to 300°C and maintain the temperature for 8 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 900°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 1000°C, and the temperature is maintained for 10 hours. Steam is then introduced at a flow rate of 5 L / min to create pores in the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 80 μm, is placed in the high-temperature region, nitrogen gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the nitrogen gas flow rate is 3 m³ 3 The system is set to 140V / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 140V, the current to 160A, and the flow rate is 7m / hour. 3 Nitrogen gas is used as the working gas, and the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon. The gaseous silicon is then supplied at a flow rate of 0.9 m³. 3 Nitrogen gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited within the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries.

[0053] In this embodiment, electrodes were manufactured using the composite lithium storage material for lithium-ion batteries prepared in this example, and the battery was assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0054] [Example 10] This embodiment provides a preparation process and characterization test for composite lithium storage materials for lithium-ion batteries, the specific steps being as follows: 1) Place 200g of glucose in a hydrothermal reactor and carry out a hydrothermal reaction at a pressure of 5 MPa. Raise the temperature to 300°C and maintain the temperature for 6 hours. Remove the material, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain non-graphitizable carbon particles. 2) Place non-graphitizable carbon particles in a rotary furnace, raise the temperature to 900°C, maintain the temperature for 1 hour, and perform a carbonization treatment to obtain a non-graphitizable carbon precursor. 3) A non-graphitizable carbon precursor is placed in a rotary furnace, the temperature is raised to 900°C, and the temperature is maintained for 5 hours. Steam is then introduced at a flow rate of 5 L / min to create pores in the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. 4) A spherical porous, non-graphitizable carbon material is placed in the condensation region of the high-frequency plasma processing apparatus, silicon powder, a by-product of diamond wire cutting of silicon material with a particle size D50 of 90 μm, is placed in the high-temperature region, argon gas is introduced into the high-frequency plasma processing apparatus to replace the air, and the argon gas flow rate is 3 m³. 3 The system is set to 150V / hour, the plasma generator of the high-frequency plasma processing device is turned on, the operating voltage is set to 150V, the current to 180A, and the flow rate is 8m / hour. 3 Using argon gas as the working gas, the plasma torch generated by the ionization of the working gas vaporizes the silicon powder placed in the high-temperature region, turning it into gaseous silicon, and the gaseous silicon is then fed at a flow rate of 1 m³. 3 Argon gas, acting as a carrier gas over time, is used to transport gaseous silicon to the condensation region of a high-frequency plasma processing device. The gaseous silicon is then deposited into the pores of a spherical porous, non-graphitizable carbon material, where it is nucleated and grown into nanometer-sized nanosilicon to obtain a composite lithium storage material for lithium-ion batteries.

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

[0056] To better illustrate the effects of the embodiments of the present invention, Comparative Example 1 will be compared with the above embodiments.

[0057] [Comparative Example 1] This comparative example provides a conventional method for preparing silicon-carbon composite materials and a performance test, the specific steps being as follows: 1) Place 200g of nanosilicon and 500g of phenolic resin powder in a hydrothermal reactor and perform hydrothermal treatment. Set the pressure to 5 MPa, raise the temperature to 300°C, and maintain the temperature for 8 hours. Remove the materials, wash and filter the filtrate until it becomes colorless and transparent, and then dry it to obtain spherical silicon-containing carbonized precursors. 2) A silicon-carbon composite material is obtained by placing a spherical silicon-containing carbonization precursor into a rotary furnace, raising the temperature to 900°C at a rate of 3°C / min, and then carbonizing it under a nitrogen gas atmosphere for 6 hours.

[0058] In this comparative example, electrodes were manufactured using the silicon-carbon composite material prepared, and a battery was assembled and tested, following the same specific process as in Example 1. The test data is shown in Table 1.

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

[0060] [Table 1]

[0061] A comparison between Comparative Example 1 and Examples 1-10 reveals that the charge ratio capacity and first-cycle Coulomb efficiency of the batteries in Examples 1-10 of the present invention are superior to those in Comparative Example 1, indicating that the batteries in Examples 1-10 of the present invention have superior cycle characteristics and charging performance. This is because the structure of the composite lithium storage material according to the examples of the present invention uses a porous, non-graphitizable carbon material as the matrix, allowing for the deposition of more nanosilicon particles within the through-pores. Consequently, it has a higher compressive density, further increasing the charge ratio capacity of the material, which is more advantageous for lithium ion insertion and removal during the charge-discharge process, while simultaneously mitigating structural damage due to body expansion and improving the material's cycle characteristics and charging performance. At the same time, the present invention can further improve the material's specific capacity and first-cycle Coulomb efficiency by adjusting the flow rate of the working gas, the flow rate of the carrier gas, and the operating voltage and current of the plasma generator. The present invention allows for the uniform deposition of gaseous silicon within the pores of a porous, non-graphitizable carbon material by controlling the flow rates of the working gas and carrier gas. When the flow rates of the working gas and carrier gas are too high, gaseous silicon deposits unevenly within the porous carbon material, and even directly on its surface, which can affect the performance of the battery.

[0062] The specific embodiments described above further elaborate on the object, technical proposal and beneficial effects of the present invention. These are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

[0063] [Note] [Note 1] A composite lithium storage material for lithium-ion batteries, The composite lithium storage material comprises a spherical porous non-graphitizable carbon material and nanosilicon grown in situ within the 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 within 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%. A composite lithium storage material characterized by the following features.

[0064] [Note 2] The average pore size 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. The composite lithium storage material according to Appendix 1, characterized by the features described herein.

[0065] [Note 3] The porous, non-graphitizable carbon material is prepared from a non-graphitizable carbon matrix, the non-graphitizable carbon matrix containing one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The aforementioned micron-sized silicon powder includes one or more of the following: silicon powder produced as a by-product during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organic silicon, or industrial silicon powder. The composite lithium storage material according to Appendix 1, characterized by the features described herein.

[0066] [Note 4] A method for preparing a composite lithium storage material for lithium-ion batteries as described in any one of the appendices 1 to 3, A non-graphitizable carbon matrix is ​​placed in a hydrothermal reactor and subjected to hydrothermal treatment. After removing the material, the filtrate is washed and filtered until it becomes colorless and transparent, and then dried to obtain non-graphitizable carbon particles. The non-graphitizable carbon particles are placed in a reaction apparatus, the temperature is raised to 700°C to 1300°C, and the temperature is maintained for 0.5 to 15 hours to subject the non-graphitizable carbon particles to a carbonization treatment. After removing the product from the carbonization treatment, it is pulverized and sieved to obtain a non-graphitizable carbon precursor. The method involves placing the non-graphitizable carbon precursor into the reaction apparatus, raising the temperature to 600°C to 1000°C, maintaining the temperature for 1 to 10 hours, and introducing a gas source during the maintenance period to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. A spherical porous, non-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 into gaseous silicon, the gaseous silicon is transported to the condensation region by a carrier gas, the gaseous silicon is deposited in the pores of the porous, non-graphitizable carbon material, nucleation occurs and it grows into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries. Includes, 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%. A preparation method characterized by the above.

[0067] [Note 5] The non-graphitizable carbon matrix comprises one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The aforementioned micron-sized silicon powder includes one or more of the following: silicon powder produced as a by-product during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organic silicon, or industrial silicon powder, and the particle size D50 of the aforementioned micron-sized silicon powder is 5 μm to 100 μm. The average pore size of the pores in the aforementioned 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 described in Appendix 4, characterized by the features described herein.

[0068] [Note 6] The aforementioned hydrothermal treatment is either pressurized hydrothermal treatment or non-pressurized hydrothermal treatment. The conditions for the aforementioned pressurized hydrothermal treatment are as follows: the pressure is set to 0.1 MPa to 10 MPa, the heating temperature to 150°C to 300°C, and the holding time to 2 hours to 8 hours. The conditions for the aforementioned non-pressurized hydrothermal treatment are as follows: the heating temperature is set to 200°C to 300°C, and the holding time is set to 5 to 30 hours. The reaction apparatus includes one of the following: a rotary furnace, a tubular furnace, a bell-shaped furnace, or a fluidized bed. The preparation method described in Appendix 4, characterized by the features described herein.

[0069] [Note 7] The gas source contains either 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 described in Appendix 4, characterized by the features described herein.

[0070] [Note 8] The protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m³. 3 / hour~3m 3 / time, The working gas is nitrogen gas or argon gas, and the flow rate of the working gas is 3 m³ 3 / hour ~ 8m 3 / time, The carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m³. 3 / hour ~ 1m 3 / time, 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 described in Appendix 4, characterized by the features described herein.

[0071] [Note 9] Includes a composite lithium storage material described in any one of the appendices 1 to 3, A negative electrode piece characterized by the following features.

[0072] [Note 10] Including the negative electrode piece described in Appendix 9, A lithium-ion battery characterized by the following features.

Claims

1. A method for preparing a composite lithium storage material for lithium-ion batteries, A non-graphitizable carbon matrix is ​​placed in a hydrothermal reactor and subjected to hydrothermal treatment. After removing the material, the filtrate is washed and filtered until it becomes colorless and transparent, and then dried to obtain non-graphitizable carbon particles. The non-graphitizable carbon particles are placed in a reaction apparatus, the temperature is raised to 700°C to 1300°C, and the temperature is maintained for 0.5 to 15 hours to subject the non-graphitizable carbon particles to a carbonization treatment. After removing the product from the carbonization treatment, it is pulverized and sieved to obtain a non-graphitizable carbon precursor. The method involves placing the non-graphitizable carbon precursor into the reaction apparatus, raising the temperature to 600°C to 1000°C, maintaining the temperature for 1 to 10 hours, and introducing a gas source during the maintenance period to perform a pore-forming treatment on the non-graphitizable carbon precursor, thereby obtaining a spherical porous non-graphitizable carbon material. A spherical porous, non-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 into gaseous silicon, the gaseous silicon is transported to the condensation region by a carrier gas, the gaseous silicon is deposited in the pores of the porous, non-graphitizable carbon material, nucleation occurs and it grows into nanometer-sized nanosilicon, thereby obtaining a composite lithium storage material for lithium-ion batteries. Includes, 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%. A preparation method characterized by the above.

2. The non-graphitizable carbon matrix comprises one or more of glucose, sucrose, polyvinylpyrrolidone, starch, polyvinylidene fluoride, phenolic resin, or polyvinyl chloride. The aforementioned micron-sized silicon powder includes one or more of the following: silicon powder produced as a by-product during diamond wire cutting of silicon materials, waste silicon powder generated during the production of organic silicon, or industrial silicon powder, and the particle size D50 of the aforementioned micron-sized silicon powder is 5 μm to 100 μm. The average pore size of the pores in the aforementioned 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 feature 1.

3. The aforementioned hydrothermal treatment is either pressurized hydrothermal treatment or non-pressurized hydrothermal treatment. The conditions for the aforementioned pressurized hydrothermal treatment are as follows: the pressure is set to 0.1 MPa to 10 MPa, the heating temperature to 150°C to 300°C, and the holding time to 2 to 8 hours. The conditions for the aforementioned non-pressurized hydrothermal treatment are as follows: the heating temperature is set to 200°C to 300°C, and the holding time is set to 5 to 30 hours. The reaction apparatus includes one of the following: a rotary furnace, a tubular furnace, a bell-shaped furnace, or a fluidized bed. The preparation method according to feature 1.

4. The gas source contains either oxygen, carbon dioxide, or water vapor, and the flow rate of the gas source is between 0.5 L / min and 20 L / min. The preparation method according to feature 1.

5. The protective gas is nitrogen gas or argon gas, and the flow rate of the protective gas is 0.5 m³. ３ / hour~3m ３ / Time is The working gas is nitrogen gas or argon gas, and the flow rate of the working gas is 3 m³ ３ / hour ~8m ３ / Time is The carrier gas is nitrogen gas or argon gas, and the flow rate of the carrier gas is 0.1 m³. ３ / hour ~ 1m ３ / Time is 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 feature 1.

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