Silicon-carbon negative electrode material for lithium ion battery, preparation method of silicon-carbon negative electrode material and lithium ion battery
By preparing silicon-carbon anode materials with dispersed nano-silicon within a carbon framework, the cycle stability and conductivity issues of traditional lithium-ion battery anode materials were solved, achieving improved performance of lithium-ion batteries with high specific capacity and high initial efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2026-03-27
AI Technical Summary
Traditional lithium-ion battery anode materials such as graphite have specific capacities close to their theoretical limits, while silicon-based anode materials suffer from poor cycle stability, poor conductivity, and low initial cycle coulombic efficiency, making it difficult to meet the demand for high capacity.
Using phenolic resin as the carbon source and solid silane as the silicon source, silicon-carbon anode materials are prepared through carbonization treatment to form a carbon skeleton and dispersed nano-silicon, which improves conductivity and alleviates volume expansion.
It improves the electrochemical performance of lithium-ion batteries, with an initial discharge specific capacity greater than 1800mAh g-1 and an initial efficiency greater than 90%. The process is simple and environmentally friendly.
Smart Images
Figure CN121748312A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery anode material technology, and in particular to a silicon-carbon anode material for lithium-ion batteries, its preparation method, and a lithium-ion battery. Background Technology
[0002] Traditional battery materials can no longer meet the development needs of high-capacity lithium-ion batteries, and the research and development and industrialization of new battery materials urgently need to be accelerated. After decades of development, the actual specific capacity of the most commonly used graphite material can reach 360-365 mAh / g, which is very close to the theoretical specific capacity (372 mAh / g). Further improvements to the performance of graphite anodes have very limited impact on the performance of lithium-ion batteries, so it is necessary to research new anode materials.
[0003] Silicon-based anodes are considered promising next-generation lithium-ion battery anode materials due to their advantages such as high energy density, wide distribution of raw materials, and suitable discharge platform. The theoretical specific capacity of elemental silicon anodes is as high as 4200 mAh / g, which is more than 10 times that of graphite anodes. Although elemental silicon materials have a high specific capacity, there are still some problems: (1) Poor cycle stability: Elemental silicon materials expand in volume by up to 300% during charging and discharging (graphite only expands by 12%), which will generate large mechanical stress. After multiple cycles, silicon particles will break and pulverize, causing anode failure; (2) Poor conductivity: The contact between silicon and conductive agents and anode binders is poor, resulting in poor overall electrode conductivity; (3) Low coulombic efficiency in the first cycle: During the charging process of lithium-ion batteries, organic electrolytes will decompose on the surface of the anode to form an SEI film, which irreversibly consumes lithium ions and reduces the capacity and energy density of lithium-ion batteries. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a silicon-carbon anode material for lithium-ion batteries, a preparation method thereof, and a lithium-ion battery. The method uses phenolic resin as a carbon source and solid silane as a silicon source to prepare the silicon-carbon anode material through carbonization. This silicon-carbon anode material is suitable for use as a negative electrode in lithium batteries and exhibits high initial efficiency and specific capacity.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] The first aspect of this invention provides a method for preparing a silicon-carbon anode material for lithium-ion batteries, comprising the following steps:
[0007] S1, solid silane and phenolic resin are placed in a ball mill jar and mechanically mixed to obtain a silane / phenolic resin composite material;
[0008] S2, the silane / phenolic resin composite material is placed in a tube furnace and carbonized under the action of a protective gas, and then crushed to obtain silicon-carbon anode material for lithium-ion batteries.
[0009] Preferably, in step S1, the solid silane is selected from one or more of triphenylsilane, triphenylchlorosilane, and 1,1,2,2-tetraphenyldisilane.
[0010] Preferably, in step S1, the mass ratio of the phenolic resin to the solid silane is 1:1 to 10.
[0011] Preferably, in step S1, during mechanical mixing, the ball mill speed is 200-600 rpm and the ball milling time is 1-6 hours.
[0012] Preferably, in step S2, the carbonization process involves a carbonization temperature of 600–1000°C, a holding time of 0.5–6 hours, and a carbonization heating rate of 1–10 degrees Celsius per minute.
[0013] Preferably, in step S2, the protective gas is selected from any one of argon, helium, hydrogen-helium mixture, hydrogen-argon mixture, hydrogen, or vacuum.
[0014] The second aspect of the present invention provides a silicon-carbon anode material for lithium-ion batteries prepared by the method for preparing silicon-carbon anode material for lithium-ion batteries as described in the first aspect of the present invention, comprising a carbon skeleton and nano-silicon dispersed within the carbon skeleton, wherein the nano-silicon has a particle size of 0.5 to 10 nm.
[0015] Preferably, the silicon-carbon anode material for the lithium-ion battery has an initial discharge specific capacity greater than 1800 mAh g at a current density of 0.1C. -1 The first-efficacy rate is greater than 90%.
[0016] A third aspect of the present invention provides a lithium-ion battery in which the negative electrode is made of silicon-carbon negative electrode material for lithium-ion batteries as described in the second aspect of the present invention.
[0017] The beneficial effects of this invention are as follows:
[0018] 1. This invention converts phenolic resin into a carbon skeleton after carbonization and solid silane into nano-silicon, which is uniformly dispersed in the carbon skeleton. This can improve the conductivity of silicon-carbon anode materials and effectively alleviate the volume expansion of silicon-based anode materials, which is beneficial to improving the electrochemical performance of lithium-ion batteries.
[0019] 2. In the process of converting solid silane into nano-silicon, the organic matter in the solid silane decomposes, generating a large number of nanopores, which can further alleviate the volume expansion of silicon-based anode materials and achieve the purpose of improving the electrochemical performance of lithium batteries.
[0020] 3. The process of this invention is simple, environmentally friendly, and easy to scale up for mass production. Attached Figure Description
[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0022] Figure 1 This is a flowchart of the preparation method of the silicon-carbon anode material for lithium-ion batteries according to the present invention;
[0023] Figure 2 The image shows the electrochemical performance of the silicon-carbon anode material for lithium-ion batteries prepared in Example 1. Detailed Implementation
[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way.
[0025] This invention addresses the problems of silicon-based anode materials by providing a feasible method for preparing silicon-carbon anode materials for lithium-ion batteries. The method uses phenolic resin as the carbon source and solid silane as the silicon source, and prepares silicon-carbon anode materials through carbonization. This method simplifies the synthesis process and reduces the cost of synthesizing anode materials.
[0026] Combination Figure 1 As shown, the present invention provides a method for preparing a silicon-carbon anode material for lithium-ion batteries, comprising the following steps:
[0027] S1, solid silane and phenolic resin are placed in a ball mill jar and mechanically mixed to obtain a silane / phenolic resin composite material;
[0028] The solid silane is selected from one or more of triphenylsilane, triphenylchlorosilane, and 1,1,2,2-tetraphenyldisilane. The mass ratio of phenolic resin to solid silane is 1:1 to 10. During mechanical mixing, the ball mill speed is 200 to 600 rpm, and the ball milling time is 1 to 6 hours.
[0029] S2, the silane / phenolic resin composite material is placed in a tube furnace and carbonized under the action of a protective gas, and then crushed to obtain silicon-carbon anode material for lithium-ion batteries.
[0030] During the carbonization process, the carbonization temperature is 600–1000℃, the holding time is 0.5–6 hours, and the carbonization heating rate is 1–10℃ / minute. The protective gas can be any one of argon, helium, a hydrogen-helium mixture, a hydrogen-argon mixture, hydrogen, or a vacuum.
[0031] In the above-mentioned preparation method of silicon-carbon anode material for lithium-ion batteries, phenolic resin is used as the carbon source and solid silane is used as the silicon source. During the carbonization process, the phenolic resin is converted into a carbon skeleton and the solid silane is converted into nano-silicon, which is uniformly dispersed in the carbon skeleton. This can improve the conductivity of silicon-carbon anode material and effectively alleviate the volume expansion of silicon-based anode material, which is beneficial to improving the electrochemical performance of lithium-ion batteries.
[0032] The silicon-carbon anode material for lithium-ion batteries prepared by the above method includes a carbon skeleton and nano-silicon dispersed in the carbon skeleton, wherein the particle size of the nano-silicon is 0.5 to 10 nm.
[0033] The aforementioned silicon-carbon anode material for lithium-ion batteries is used at 0.1C (1C = 1800 mA g). -1 The initial discharge specific capacity at the current density is greater than 1800 mAh g. -1 The first-efficacy rate is greater than 90%.
[0034] The present invention also provides a lithium-ion battery, wherein the negative electrode adopts the silicon-carbon negative electrode material for lithium-ion batteries prepared above.
[0035] The following section provides a further description of the silicon-carbon anode material for lithium-ion batteries and its preparation method, using specific examples.
[0036] Example 1
[0037] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0038] 500g of triphenylsilane and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 250rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 800℃ at 2℃ / min in a hydrogen-argon (5%-95%) atmosphere. The temperature was maintained for 6 hours, and the mixture was pulverized to obtain the silicon-carbon anode material for lithium-ion batteries.
[0039] In this embodiment, the lithium-ion battery uses silicon-carbon anode material as the anode material, lithium metal sheet as the cathode, Celgard 2400 as the separator, and 1M LiFP6 dissolved in EC:DEC:EMC (1:1:1) + 5% FEC as the electrolyte for electrochemical testing. Figure 2 The electrochemical performance of the synthesized silicon-carbon anode material is shown. This silicon-carbon anode material exhibits electrochemical properties at 0.1C (1C = 1800 mA g / g). -1 The initial discharge specific capacity at the current density is 1820 mAh g. -1 The initial efficacy rate was 90.37%.
[0040] Example 2
[0041] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0042] 550g of triphenylchlorosilane and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 300rpm for 3 hours to obtain a silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at a hydrogen-helium (5%-95%) atmosphere at a rate of 2℃ / min, held at that temperature for 5 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1816mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.79%.
[0043] Example 3
[0044] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0045] 250g of 1,1,2,2-tetraphenyldisilane and 100g of phenolic resin aerogel were placed in a ball mill jar and mechanically mixed at 400rpm for 3 hours to obtain a silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at 3℃ / min under an argon atmosphere, held at that temperature for 3 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1803mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.88%.
[0046] Example 4
[0047] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0048] 500g of triphenylsilane and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 250rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at a hydrogen-argon (5%-95%) atmosphere at a rate of 2℃ / min, held at that temperature for 5 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1815mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.78%.
[0049] Example 5
[0050] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0051] 500g of triphenylsilane and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 250rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 1000℃ at a hydrogen-argon (5%-95%) atmosphere at a rate of 2℃ / min, held at that temperature for 3 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1808mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.56%.
[0052] Example 6
[0053] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0054] 250g of triphenylsilane, 275g of triphenylchlorosilane, and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 300rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at a hydrogen-argon (5%-95%) atmosphere at a rate of 2℃ / min, held at that temperature for 5 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1813mAhg at a current density of 0.1C. -1 The initial efficacy rate was 90.67%.
[0055] Example 7
[0056] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0057] 250g of triphenylsilane, 125g of 1,1,2,2-tetraphenyldisilane, and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 400rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at 2.5℃ / min under a hydrogen-argon (5%-95%) atmosphere, held at that temperature for 5 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1815mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.72%.
[0058] Example 8
[0059] The specific process for preparing the silicon-carbon anode material for lithium-ion batteries in this embodiment is as follows:
[0060] 165g of triphenylsilane, 165g of triphenylchlorosilane, 85g of 1,1,2,2-tetraphenyldisilane, and 100g of phenolic resin were placed in a ball mill jar and mechanically mixed at 400rpm for 3 hours to obtain a solid silane / phenolic resin composite material. The composite was then placed in a tube furnace and heated to 900℃ at 2.5℃ / min under a hydrogen-helium (5%-95%) atmosphere, held at that temperature for 5 hours, and pulverized to obtain the silicon-carbon anode material. This silicon-carbon anode material exhibited an initial discharge specific capacity of 1816mAh g at a current density of 0.1C. -1 The initial efficacy rate was 90.84%.
[0061] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for preparing a silicon-carbon anode material for lithium-ion batteries, characterized in that, Includes the following steps: S1, solid silane and phenolic resin are placed in a ball mill jar and mechanically mixed to obtain a silane / phenolic resin composite material; S2, the silane / phenolic resin composite material is placed in a tube furnace and carbonized under the action of a protective gas, and then crushed to obtain silicon-carbon anode material for lithium-ion batteries.
2. The method for preparing silicon-carbon anode material for lithium-ion batteries as described in claim 1, characterized in that, In step S1: the solid silane is selected from one or more of triphenylsilane, triphenylchlorosilane, and 1,1,2,2-tetraphenyldisilane.
3. The method for preparing silicon-carbon anode material for lithium-ion batteries as described in claim 1, characterized in that, In step S1, the mass ratio of the phenolic resin to the solid silane is 1:1 to 10.
4. The method for preparing silicon-carbon anode material for lithium-ion batteries as described in claim 1, characterized in that, In step S1, during mechanical mixing, the ball mill speed is 200-600 rpm and the ball milling time is 1-6 hours.
5. The method for preparing silicon-carbon anode material for lithium-ion batteries as described in claim 1, characterized in that, In step S2, the carbonization process involves a carbonization temperature of 600–1000°C, a holding time of 0.5–6 hours, and a carbonization heating rate of 1–10 degrees Celsius per minute.
6. The method for preparing silicon-carbon anode material for lithium-ion batteries as described in claim 1, characterized in that, In step S2, the protective gas is selected from any one of argon, helium, hydrogen-helium mixture, hydrogen-argon mixture, hydrogen, or vacuum.
7. A silicon-carbon anode material for lithium-ion batteries prepared by the method for preparing silicon-carbon anode material for lithium-ion batteries according to any one of claims 1-6, characterized in that, It includes a carbon skeleton and nano-silicon dispersed within the carbon skeleton, wherein the nano-silicon has a particle size of 0.5–10 nm.
8. The silicon-carbon anode material for lithium-ion batteries as described in claim 7, characterized in that, The silicon-carbon anode material used in the lithium-ion battery exhibits an initial discharge specific capacity greater than 1800 mAh g at a current density of 0.1C. -1 The first-efficacy rate is greater than 90%.
9. A lithium-ion battery, characterized in that, Its negative electrode uses the silicon-carbon negative electrode material for lithium-ion batteries as described in claim 8.