Modified prelithiated silicon-oxygen material, method of making, use and lithium-ion battery

Abstract

The application discloses a modified pre-lithiated silicon-oxygen material and a preparation method, application and lithium ion battery thereof. The preparation method of the modified pre-lithiated silicon-oxygen material is as follows: a layer of epoxy acrylic resin polymer is coated on the surface of the pre-lithiated silicon-oxygen material by means of ultraviolet light polymerization to obtain the modified pre-lithiated silicon-oxygen material; the coating comprises polymerizing a mixture of epoxy acrylic resin, a photoinitiator and the pre-lithiated silicon-oxygen material under ultraviolet light radiation; the weight ratio of the epoxy acrylic resin to the pre-lithiated silicon-oxygen material is (3-10):100; and the weight ratio of the photoinitiator to the epoxy acrylic resin is 0.1wt%-5wt%. The modified pre-lithiated silicon-oxygen material prepared by the application has the characteristics of high first charge-discharge efficiency, high capacity and good cycle performance, and the preparation method is simple, low in cost, wide in application range and beneficial to industrial production.

Description

Technical Field

[0001] This invention specifically relates to a modified pre-lithiated silicon oxide material, its preparation method, applications, and lithium-ion batteries. Background Technology

[0002] With the escalating crisis of fossil fuels and the global greenhouse effect, developing new energy sources has become an urgent task. The development of new energy sources relies heavily on advanced energy storage technologies, among which lithium-ion batteries have become a focus of attention due to their high energy density, long cycle life, and high average output voltage. Especially today, the rapid pace of product upgrades in consumer electronics, the booming development of the electric vehicle industry, the rapid promotion of smart grids, and the expanding demand in other technological fields have further propelled the rapid development of the lithium-ion battery industry.

[0003] To meet the ever-increasing demands for driving range in practical applications of new energy vehicles, power battery materials are also developing towards providing higher energy density. Traditional graphite anodes for lithium-ion batteries can no longer meet current needs, making high-energy-density anode materials a new hot topic for companies. Silicon-based anode materials, due to their abundant reserves and ultra-high theoretical specific capacity, are gradually becoming the top choice for battery companies and lithium battery material manufacturers to improve anodes, and are one of the most promising next-generation lithium-ion battery anode materials. Silicon-oxygen anode materials have a high theoretical specific capacity, theoretically providing 10 times the storage capacity of traditional graphite lithium-ion batteries, while also possessing extremely high charging efficiency. However, silicon-oxygen anode materials have a relatively low initial coulombic efficiency (approximately 70%). Pre-lithiation is an effective method to improve its initial efficiency, but pre-lithiated silicon-oxygen anode materials have many problems, such as excessive residual lithium salts on the surface and the susceptibility of side reactions at the material interface.

[0004] Chinese patent document CN112820863A discloses a modified pre-lithiated silicon oxide material, which uses an aluminum phosphate salt polymer to coat the pre-lithiated silicon oxide material. Although the pre-lithiated silicon oxide material has been modified, it still has the problems of requiring further heat treatment after coating the modified layer, complicated preparation steps, and low first-efficiency in lithium-ion battery applications. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of existing technologies, such as cumbersome preparation steps for modified pre-lithiated silicon oxide materials and low initial charge-discharge efficiency in lithium-ion battery applications. This invention provides a modified pre-lithiated silicon oxide material, its preparation method, applications, and a lithium-ion battery thereof. The modified pre-lithiated silicon oxide material prepared by this invention exhibits high initial charge-discharge efficiency, high capacity, and good cycle performance when used in lithium-ion battery manufacturing. Its preparation method is simple, low-cost, widely applicable, and conducive to industrial production.

[0006] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0007] This invention provides a method for preparing a modified pre-lithiated silica material, which includes the following steps: coating the surface of the pre-lithiated silica material with an epoxy acrylate polymer by ultraviolet light polymerization to obtain the modified pre-lithiated silica material.

[0008] The coating process involves polymerizing a mixture of epoxy acrylate resin, photoinitiator, and pre-lithiated silica material under ultraviolet radiation.

[0009] The weight ratio of the epoxy acrylate resin to the pre-lithiated silica material is (3-10):100; the weight ratio of the photoinitiator to the epoxy acrylate resin is 0.1wt%-5wt%.

[0010] In this invention, the weight ratio of the epoxy acrylate resin to the pre-lithiated silica material is preferably (3.5-9):100, more preferably (4-6):100, for example 5:100.

[0011] In this invention, the epoxy acrylate may be a conventional epoxy acrylate in the art, preferably a bisphenol A type epoxy acrylate, a phenolic epoxy acrylate, an epoxidized oil acrylate, or a modified epoxy acrylate.

[0012] In this invention, the weight ratio of the photoinitiator to the epoxy acrylate resin is preferably 0.2wt%-4wt%, for example 0.2wt%, 1wt%, or 2wt%, more preferably 1.5wt%-3wt%.

[0013] In this invention, the photoinitiator can be conventional in the art, preferably an aryl alkyl ketone compound, and more preferably one or more of benzoin derivatives, biphenyl ketals, α,α-dialkoxyacetophenones, α-hydroxyalkylphenyl ketones, α-aminoalkylphenyl ketones, and acylphosphine oxides, such as photoinitiator 184 (1-hydroxycyclohexylphenyl ketone), photoinitiator 2959 (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone), photoinitiator 651 (benzoin dimethyl ether), and photoinitiator 907 (2-methyl-1- (4-Methylthiophenyl)-2-morpholino-1-propanone, photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone), photoinitiator 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone), photoinitiator 819 (phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide), photoinitiator TPO (diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide), photoinitiator MBF (methyl benzoylformate) or photoinitiator 754 (a mixture of benzoylformate esters).

[0014] In this invention, the photoinitiator is preferably photoinitiator 819 (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) and photoinitiator 184 (1-hydroxycyclohexylphenyl ketone).

[0015] When the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 1-hydroxycyclohexylphenyl ketone, the weight ratio of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide to 1-hydroxycyclohexylphenyl ketone can be conventional in the art, preferably 1:3.

[0016] In a preferred embodiment, the photoinitiator is 0.5 wt% of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 1.5 wt% of 1-hydroxycyclohexylphenyl ketone, where wt% is the percentage of the weight of each component to the weight of the epoxy acrylate resin.

[0017] In this invention, the polymerization time can be 2-8 hours, preferably 2.5-7.5 hours, more preferably 3-5 hours, for example 4 hours.

[0018] In this invention, the polymerization speed can be conventional in the art, preferably 1000-2000 r / min, more preferably 1200-1700 r / min, for example 1500 r / min.

[0019] In this invention, the wavelength range of the ultraviolet radiation can be conventional in the art, preferably 1-380nm, more preferably 315-380nm, for example 365nm or 370nm.

[0020] In this invention, the preparation method of the mixture of epoxy acrylate resin, photoinitiator and pre-lithiated silica material can be conventional in the art, and preferably includes heating and mixing a solution containing the epoxy acrylate resin and the photoinitiator with the pre-lithiated silica material.

[0021] The preparation method of the solution containing the epoxy acrylate resin and the photoinitiator can be conventional in the art. Generally, the epoxy acrylate resin and the photoinitiator are dissolved in an organic solvent by stirring.

[0022] The organic solvent can be a solvent conventional in the art capable of dissolving the epoxy acrylate resin, generally one or more of ethyl acetate, acetone, xylene, tetrahydrofuran, propylene carbonate, and glycidyl ether.

[0023] The volume ratio of the epoxy acrylate resin to the organic solvent can be conventional in the art, preferably 1:1 or 1:2.

[0024] The temperature of the heating and mixing process can be 60-90℃, for example, 80℃.

[0025] The heating and mixing time can be 10-60 minutes, for example, 30 minutes.

[0026] The heating and mixing are generally carried out under stirring conditions. The stirring speed is preferably 600-1000 r / min, for example 800 r / min.

[0027] During the heating and mixing process, the evaporated solvent is collected in a collection device. The collection device can be conventional in the art, such as a collection bottle.

[0028] Preferably, the solution containing epoxy acrylate resin and photoinitiator is sprayed into the pre-lithiated silica material before heating and mixing.

[0029] In this invention, the preparation method of the pre-lithiated silicon oxide material can be conventional in the art, including the following steps: sequentially carbon-coating and pre-lithiating the silicon oxide material to obtain the pre-lithiated silicon oxide material.

[0030] The silicon-oxygen material can be conventional in the art, such as commercially available SiO material.

[0031] The carbon coating can be conventional in the art, for example, it can be carried out by liquid-phase coating using an organic carbon source.

[0032] The organic carbon source is preferably an organic petroleum, asphalt, paraffin, or common resin, and more preferably asphalt.

[0033] Preferably, the carbon coating is achieved by mixing silicon-oxygen materials and an organic carbon source and then heating and stirring them.

[0034] The mass ratio of the silicon-oxygen material to the organic carbon source can be conventional in the art, and preferably 100:11.

[0035] The heating and stirring temperature can be conventional in the art, preferably 450-900°C, for example 500°C or 850°C.

[0036] The heating and stirring time can be conventional in the art, preferably 6-15 hours, such as 5 hours, 6 hours or 11 hours.

[0037] The heating and stirring are preferably carried out first at 400-600℃ for 4-8 hours, and then at 800-900℃ for 4-8 hours.

[0038] In a preferred embodiment, the heating and stirring are first carried out at 500°C for 6 hours, and then at 850°C for 5 hours.

[0039] The mixing is preferably mechanical. The mechanical mixing time is preferably 5-30 minutes, for example 10 minutes.

[0040] The carbon coating is preferably carried out in a high-temperature vacuum stirring device.

[0041] In the pre-lithiation process, the lithium-containing compound used can be a conventional lithium-containing compound used in the art to prepare pre-lithiated silicon oxide materials, generally an organic lithium compound or an inorganic lithium compound, preferably an inorganic lithium compound, such as one or more of lithium carbonate, lithium hydroxide, lithium aluminum phosphate, lithium hydride, lithium bromide and metallic lithium.

[0042] The pre-lithiation operation and conditions can be conventional in the art, and preferably include the following steps: mixing the carbon-coated silicon oxide material with a lithium-containing compound and then calcining it.

[0043] The mass ratio of the carbon-coated silicon-oxygen material to the lithium-containing compound can be conventional in the art, generally capable of completely converting the lithium-containing compound into lithium silicate, preferably 100:(1-20), for example 100:10.

[0044] The roasting is generally carried out in a tube furnace.

[0045] The roasting atmosphere is generally an inert atmosphere, such as argon.

[0046] The roasting temperature can be 400-800℃, for example 400℃, 500℃, 600℃, 700℃ or 800℃.

[0047] The roasting time can be 1-12 hours, for example 2 hours, 4 hours, 6 hours or 8 hours.

[0048] The present invention also provides a modified pre-lithiated silicon oxide material prepared by the preparation method described above.

[0049] The present invention also provides a modified pre-lithiated silica material, comprising a pre-lithiated silica material and a coating layer covering the surface of the pre-lithiated silica material, wherein the coating layer comprises an epoxy acrylate resin polymer, and the coating layer accounts for 1 wt%-10 wt% of the weight of the pre-lithiated silica material.

[0050] In this invention, the modified pre-lithiated silicon oxide material generally has a core-shell structure, with the pre-lithiated silicon oxide material as the core and the coating layer as the shell.

[0051] In this invention, the pre-lithiated silicon oxide material may include silicon oxide, silicon grains, and lithium silicate, wherein the silicon grains are distributed in the lithium silicate and the silicon oxide.

[0052] The silicon oxide is generally SiOx 0 <x≤1。

[0053] The silicon grains have a diameter of 2-20 nm, preferably 1-10 nm. The size of the silicon grains increases in a gradient from the core center to the core surface.

[0054] The lithium silicate can be conventional in the art, generally including Li2SiO3 or Li2Si2O5.

[0055] In this invention, the particle size of the pre-lithiated silicon oxide material can be 1-20 μm.

[0056] In this invention, a carbon layer is at least partially covered between the pre-lithiated silicon oxide material and the coating layer, and the thickness of the carbon layer is preferably no more than 20 nm.

[0057] The carbon layer preferably accounts for 3wt%-6wt% of the total weight of the pre-lithiated silicon oxide material, for example, 6wt%.

[0058] In this invention, the thickness of the coating layer can be 10-100 nm, preferably 10-60 nm.

[0059] In this invention, the coating layer preferably accounts for 3wt%-7wt% of the weight percentage of the pre-lithiated silicon oxide material, for example, 5wt%.

[0060] In this invention, the BET specific surface area of ​​the modified pre-lithiated silicon oxide material is preferably 0.5-10 m². 2 / g.

[0061] The present invention also provides an application of the aforementioned modified pre-lithiated silicon oxide material as an electrode material in lithium-ion batteries.

[0062] The electrode material is preferably a negative electrode material.

[0063] The present invention also provides a lithium-ion battery comprising the modified pre-lithiated silicon oxide material as described above.

[0064] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0065] The reagents and raw materials used in this invention are all commercially available.

[0066] The positive and progressive effects of this invention are as follows:

[0067] (1) The preparation method of the modified pre-lithiated silicon oxide material of the present invention is simple, does not require high temperature heat treatment, is low in cost, has good controllability, uniform coating, wide applicability and is conducive to industrial production, and has the prospect of further promotion and application.

[0068] (2) The modified pre-lithiated silicon oxide material prepared by the present invention has good stability and is not prone to agglomeration during the slurry preparation process.

[0069] (3) The lithium-ion battery prepared using the modified pre-lithiated silicon oxide material of the present invention can achieve the effects of high initial charge and discharge efficiency, high capacity, high initial coulombic efficiency and good cycle performance. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the structure of the modified pre-lithiated silicon-oxygen material prepared according to the present invention.

[0071] Figure 2 The image shows the XRD pattern of the modified pre-lithiated silicon oxide material prepared in Example 1.

[0072] Figure Labels

[0073] Silicon grain 1

[0074] A mixture of silicon oxide and lithium silicate 2

[0075] Carbon layer 3

[0076] Epoxy acrylate resin polymer layer 4 Detailed Implementation

[0077] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0078] In the following examples and comparative examples, the bisphenol A epoxy acrylate used was model G311A80, purchased from Guangzhou Lihou Trading Co., Ltd.; the epoxy resin used was CYD-128, purchased from Sinopec Baling Petrochemical Co., Ltd.

[0079] The instrument used in the ultraviolet polymerization process is a KEINU Precision Optoelectronics (Suzhou), model A2020.

[0080] Example 1

[0081] Step (1)

[0082] The silica raw material and liquid asphalt were mechanically mixed for 10 minutes at a mass ratio of 100:11. The mixed material was then added to a high-temperature vacuum mixing device and stirred at 500°C for 6 hours, followed by stirring at 850°C for 5 hours to obtain carbon-coated silica material.

[0083] Step (2)

[0084] The carbon-coated silicon oxide material and lithium hydroxide were calcined in an argon atmosphere at a mass ratio of 100:10 for 8 hours at a temperature of 700°C to obtain the pre-lithiated silicon oxide material.

[0085] Step (3)

[0086] The coating agent (bisphenol A epoxy acrylate) and photoinitiator were dispersed in ethyl acetate and stirred until homogeneous to obtain a mixed solution. The weight ratio of the photoinitiator to the bisphenol A epoxy acrylate resin was 2%. The photoinitiators were phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 1-hydroxycyclohexylphenyl ketone, with weight ratios of 0.5% and 1.5% respectively to the bisphenol A epoxy acrylate resin. The volume ratio of bisphenol A epoxy acrylate to ethyl acetate was 1:1.

[0087] The pre-physicochemically treated silica material was added to a high-speed mixer at a weight ratio of 100:5 (pre-physicochemically treated silica material to coating agent). The mixture containing bisphenol A epoxy acrylate and a photoinitiator was sprayed into the mixer containing the pre-physicochemically treated silica material. Heating and stirring were carried out at 80°C and 800 rpm for 30 minutes, ensuring that ethyl acetate had been collected in the collection bottle. The collection bottle was then sealed, and heating was stopped. An ultraviolet light source was turned on for ultraviolet radiation. The stirring speed of the high-speed mixer was adjusted to 1500 rpm, and stirring continued for 4 hours under 370 nm ultraviolet light irradiation to obtain the pre-physicochemically treated silica material.

[0088] Example 2

[0089] Except for adjusting the weight ratio of photoinitiator to bisphenol A epoxy acrylate resin in step (3) to 0.1%, all other operations and conditions are the same as in Example 1.

[0090] Example 3

[0091] Except for adjusting the weight ratio of photoinitiator to bisphenol A epoxy acrylate resin in step (3) to 5%, the other operations and conditions are the same as in Example 1.

[0092] Example 4

[0093] Except for adjusting the weight ratio of photoinitiator to bisphenol A epoxy acrylate resin in step (3) to 0.2%, all other operations and conditions are the same as in Example 1.

[0094] Example 5

[0095] Except for adjusting the weight ratio of photoinitiator to bisphenol A epoxy acrylate resin in step (3) to 1%, all other operations and conditions are the same as in Example 1.

[0096] Example 6

[0097] Except for adjusting the weight ratio of pre-physicochemical silica material and coating agent in step (3) to 100:3, all other operations and conditions are the same as in Example 1.

[0098] Example 7

[0099] Except for adjusting the weight ratio of pre-physicochemical silica material and coating agent in step (3) to 100:10, the other operations and conditions are the same as in Example 1.

[0100] Example 8

[0101] Except for adjusting the time under ultraviolet light irradiation in step (3) to 2 hours, the other operations and conditions are the same as in Example 1.

[0102] Example 9

[0103] Except for adjusting the time under ultraviolet light irradiation in step (3) to 8 hours, the other operations and conditions are the same as in Example 1.

[0104] Comparative Example 1

[0105] Except for step (3), all other operations and conditions are the same as in Example 1.

[0106] Comparative Example 2

[0107] Except for replacing the bisphenol A epoxy acrylate resin in step (3) with epoxy resin CYD-128, all other operations and conditions are the same as in Example 1.

[0108] Example 1

[0109] 1. Schematic diagram of the structure of modified pre-lithiated silicon oxide material

[0110] The structural schematic diagrams of the modified pre-lithiated silicon oxide materials obtained in Examples 1-9 of this invention are shown below. Figure 1 As shown, the core surface of the mixture 2 of silicon oxide and lithium silicate is sequentially coated with a carbon layer 3 and an epoxy acrylate resin polymer layer 4, and silicon grains 1 are distributed inside the silicon oxide and lithium silicate 2; wherein, silicon oxide refers to SiO x (0 <x<2)。

[0111] Lithium silicates generally include Li2SiO3.

[0112] The particle size of silicon grain 1 can be 2-20 nm, and the size of the silicon grain is determined by X-ray powder diffraction.

[0113] The particle size of pre-lithiated silicon oxide materials can be 1-20 μm.

[0114] A carbon layer 3 is at least partially covered between the pre-lithiated silicon oxide material and the coating layer, and the thickness of the carbon layer 3 does not exceed 20 nm. The carbon layer accounts for 6 wt% of the total weight of the pre-lithiated silicon oxide material.

[0115] The thickness of the coating layer can range from 10 nm to 60 nm. The coating layer accounts for 5 wt% of the weight of the pre-lithiated silicon oxide material.

[0116] 2. XRD test

[0117] The modified pre-lithiated silicon oxide material obtained in Example 1 was tested using an X-ray powder diffractometer, and the diffraction pattern was obtained, as shown below. Figure 2 As shown. From Figure 2 As can be seen from the above, the modified pre-lithiated silicon oxide material obtained by the present invention has diffraction peaks of silicon grains and diffraction peaks of Li2SiO3, indicating that the modified pre-lithiated silicon oxide material contains crystalline silicon and lithium silicate phases.

[0118] 3. Measurement of electrochemical performance

[0119] The epoxy acrylate resin-coated pre-lithiated silicon oxide composite materials prepared in the various embodiments and comparative examples were coated onto copper foil and then vacuum dried and rolled to prepare negative electrode sheets. A coin cell battery was assembled in an argon-filled inert gas glove box system using a 1 mol / L LiPF6 three-component mixed solvent with a volume ratio of ethyl carbonate:dimethyl carbonate:ethyl methyl carbonate = 1:1:1 as the electrolyte, a polypropylene microporous membrane as the separator, and a lithium metal sheet as the positive electrode. Charge-discharge tests were conducted on the coin cells using a battery testing system at room temperature, with a constant current charge-discharge of 0.1C and a charge-discharge voltage limited to 0.005–1.5V. Cycle stability was determined by comparing the percentage of the initial specific capacity after 200 charge-discharge cycles under the same test conditions. A lower value indicates a faster capacity decrease and poorer cycle stability. Charge-discharge data are shown in Tables 1 and 2.

[0120] 4. Gas production test method

[0121] 5 mL of the prepared slurry was drawn into a syringe, sealed, and marked at the movable piston. The piston movement distance was observed after 48 hours. The relevant data are shown in Table 3.

[0122] Table 1

[0123]

[0124]

[0125] Table 2

[0126] <![CDATA[Capacity (mAh / g) > <![CDATA[ 1296.9 ]]> <![CDATA[ 1388.1 ]]> <![CDATA[ 1342.0 ]]> <![CDATA[ 1314.2 ]]> <![CDATA[ 1227.3 ]]> <![CDATA[Initial Coulombic efficiency (％) > <![CDATA[ 88.2 ]]> <![CDATA[ 88.3 ]]> <![CDATA[ 86 ]]> <![CDATA[ 81 ]]> <![CDATA[ 79.6 ]]> Cyclic performance <![CDATA[ 89％ ]]> <![CDATA[ 80％ ]]> <![CDATA[ 84％ ]]> <![CDATA[ 78％ ]]> <![CDATA[ 84％ ]]>

[0127] Table 3

[0128]

[0129] The experimental results above show that the epoxy acrylate resin coating layer prepared in this invention can form a stable interface and maintain relatively stable electrochemical performance. Simultaneously, during the slurry preparation process, it was found that the modified pre-lithiated silicon-oxygen anode material exhibits good slurry stability and does not aggregate.

[0130] As can be seen from Examples 1-5, the amount of initiator added has a significant impact on the performance of the prepared modified pre-lithiated silicon oxide material. When the weight ratio of photoinitiator to epoxy acrylate resin is 0.1%-5%, the prepared modified pre-lithiated silicon oxide material not only has high capacity, but also excellent first-cycle efficiency and cycling performance. In particular, when the weight ratio of photoinitiator to epoxy acrylate resin is 0.2%-2%, the prepared modified pre-lithiated silicon oxide material not only has excellent electrochemical performance, but also does not produce gas. Among them, the first-cycle capacity of the optimal Example 1 of this application can reach 1406.9 mAh / g, the first-cycle efficiency is as high as 91.0%, and the cycling performance is 89%.

[0131] As can be seen from Examples 1 and 6-7, the amount of coating agent added has a significant impact on the performance of the modified pre-lithiated silicon oxide material. When the weight ratio of the coating agent to the pre-lithiated silicon oxide material is (3-10):100, the prepared modified pre-lithiated silicon oxide material not only has excellent electrochemical performance, but also does not easily generate gas.

[0132] As can be seen from Examples 1 and 8-9, the duration of ultraviolet irradiation has a significant impact on the performance of the prepared modified pre-lithiated silicon oxide materials. When the irradiation time is 2-8 hours, the prepared modified pre-lithiated silicon oxide materials not only have excellent electrochemical performance, but also do not easily generate gas.

[0133] Comparative Example 1 shows that the product without epoxy resin or acrylic resin coating has lower reversible capacity and lower initial efficiency.

[0134] Comparative Example 2 shows that although other resins can suppress gas production to a certain extent under certain conditions, they still produce a small amount of foam, affecting the material's circulation, capacity, and first-efficiency.

Claims

1. A method for preparing a modified pre-lithiated silicon oxide material, characterized in that, It includes the following steps: The modified pre-lithiated silica material is prepared by coating the surface of the pre-lithiated silica material with an epoxy acrylate polymer via ultraviolet light polymerization. The coating process involves polymerizing a mixture of epoxy acrylate resin, photoinitiator, and pre-lithiated silica material under ultraviolet radiation. The weight ratio of the epoxy acrylate resin to the pre-lithiated silica material is (3-10):100; the weight ratio of the photoinitiator to the epoxy acrylate resin is 0.1wt%-5wt%.

2. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 1, characterized in that, The preparation method of the modified pre-lithiated silicon oxide material satisfies one or more of the following conditions: (1) The weight ratio of the epoxy acrylate resin to the pre-lithiated silicone material is (3.5-9):100; (2) The weight ratio of the photoinitiator to the epoxy acrylate resin is 0.2wt%-4wt%; (3) The polymerization time is 2-8 hours; (4) The wavelength range of the ultraviolet radiation is 1-380nm.

3. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 2, characterized in that, The weight ratio of the epoxy acrylate resin to the pre-lithiated silica material is (4-6):

100.

4. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 3, characterized in that, The weight ratio of the epoxy acrylate resin to the pre-lithiated silica material is 5:

100.

5. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 2, characterized in that, The weight ratio of the photoinitiator to the epoxy acrylate resin is 1.5wt%-3wt%.

6. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 2, characterized in that, The weight ratio of the photoinitiator to the epoxy acrylate resin is 0.2wt%, 1wt%, or 2wt%.

7. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 2, characterized in that, The polymerization time is 2.5-7.5 hours.

8. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 7, characterized in that, The polymerization time is 3-5 hours.

9. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 8, characterized in that, The polymerization time is 4 hours.

10. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 2, characterized in that, The wavelength range of the ultraviolet radiation is 315-380nm.

11. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 10, characterized in that, The wavelength of the ultraviolet radiation is 365 nm.

12. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 1, characterized in that, The photoinitiator is an arylalkyl ketone compound; And / or, the epoxy acrylate resin is a bisphenol A type epoxy acrylate, a phenolic epoxy acrylate, an epoxidized oil acrylate, or a modified epoxy acrylate.

13. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 12, characterized in that, The photoinitiator is one or more of the following: benzoin derivatives, biphenyl ketals, α,α-dialkoxyacetophenones, α-hydroxyalkylphenyl ketones, α-aminoalkylphenyl ketones, and acylphosphine oxides.

14. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 13, characterized in that, The photoinitiator is one or more of photoinitiator 184, photoinitiator 2959, photoinitiator 651, photoinitiator 907, photoinitiator 369, photoinitiator 1173, photoinitiator 819, photoinitiator TPO, photoinitiator MBF, or photoinitiator 754.

15. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 14, characterized in that, The photoinitiators are photoinitiator 819 and photoinitiator 184.

16. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 1, characterized in that, The method for preparing the mixture of epoxy acrylate resin, photoinitiator and pre-lithiated silica material includes heating and mixing a solution containing the epoxy acrylate resin and the photoinitiator with the pre-lithiated silica material.

17. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 16, characterized in that, The temperature for heating and mixing is 60-90℃.

18. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 17, characterized in that, The temperature at which the mixture is heated is 80°C.

19. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 16, characterized in that, The heating and mixing time is 10-60 minutes.

20. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 19, characterized in that, The heating and mixing time is 30 minutes.

21. The method for preparing the modified pre-lithiated silicon oxide material as described in claim 1, characterized in that, The preparation method of the pre-lithiated silicon-oxygen material includes the following steps: sequentially carbon-coating and pre-lithiating the silicon-oxygen material to obtain the pre-lithiated silicon-oxygen material.

22. A modified pre-lithiated silicon oxide material, characterized in that, It is prepared by the method for preparing the modified pre-lithiated silicon oxide material according to any one of claims 1-21.

23. A modified pre-lithiated silicon oxide material, characterized in that, It includes a pre-lithiated silica material and a coating layer covering the surface of the pre-lithiated silica material. The coating layer includes an epoxy acrylate resin polymer, and the coating layer accounts for 1wt%-10wt% of the weight of the pre-lithiated silica material.

24. The modified pre-lithiated silicon oxide material as described in claim 23, characterized in that, The modified pre-lithiated silicon oxide material described above satisfies one or more of the following conditions: (1) The pre-lithiated silicon oxide material includes silicon oxide, silicon grains and lithium silicate, wherein the silicon grains are distributed in the lithium silicate and the silicon oxide; (2) The particle size of the pre-lithiated silicon oxide material is 1-20 μm; (3) At least a carbon layer covers the space between the pre-lithiated silicon oxide material and the coating layer, and the thickness of the carbon layer does not exceed 20 nm; (4) The thickness of the coating layer is 10-100 nm; (5) The coating layer accounts for 3wt%-7wt% of the weight of the pre-lithiated silicon oxide material; (6) The BET specific surface area of ​​the modified pre-lithiated silicon oxide material is 0.5-10 m². 2 / g.

25. The modified pre-lithiated silicon oxide material as described in claim 24, characterized in that, The carbon layer accounts for 3wt%-6wt% of the total weight of the pre-lithiated silicon oxide material.

26. The modified pre-lithiated silicon oxide material as described in claim 25, characterized in that, The carbon layer accounts for 6 wt% of the total weight of the pre-lithiated silicon oxide material.

27. The modified pre-lithiated silicon oxide material as described in claim 24, characterized in that, The thickness of the coating layer is 10-60 nm.

28. The modified pre-lithiated silicon oxide material as described in claim 24, characterized in that, The coating layer accounts for 5 wt% of the weight of the pre-lithiated silicon oxide material.

29. The application of a modified pre-lithiated silicon oxide material as an electrode material in lithium-ion batteries, as described in any one of claims 22-28.

30. A lithium-ion battery, characterized in that, It includes the modified pre-lithiated silicon oxide material as described in any one of claims 22-28.

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