Carbon aerogel composite lithium battery negative electrode and preparation method thereof
By preparing the porous structure of carbon aerogel composite, the problems of volume expansion of silicon-based materials in lithium batteries and electrolyte corrosion are solved, the conductive performance and capacity of the negative electrode are improved, and the cycle life of the battery is extended.
Patent Information
- Application Number
- CN202311823685.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
The specific capacity of existing lithium battery negative electrode materials such as carbon-based materials is lower, while silicon-based materials have problems such as volume expansion, electrolyte corrosion and charge transfer difficulties during charging and discharging, which affects battery performance.
A fibrous complex is formed by using template materials and oxidizing agents, a hydrogel is formed through monomer materials, and a porous carbon aerogel is prepared by freeze-drying. The conductive network composed of carbon nanotubes is used as the adhesion framework of the active substance, buffering volume expansion and improving conductive properties.
It improves the conductivity and capacity of the negative electrode, reduces the damage to the battery structure by volume expansion, extends the cycle life, enhances the soaking effect of the electrolyte, and reduces the transmission distance of lithium ions.
Smart Images
Figure CN120237161A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium battery anodes, and particularly to a carbon aerogel composite lithium battery anode and a preparation method thereof. Background Art
[0002] At present, the lithium battery market is in a stage of rapid growth. With the rapid development of the electric vehicle and power energy storage markets, the demand for lithium batteries has increased significantly, thus posing higher requirements for the capacity of lithium-ion batteries. A lithium-ion battery mainly consists of positive and negative electrodes, an electrolyte, a thin film, a current collector, and a casing. Among them, the electrode material plays a direct role in the battery capacity. Currently, the commonly used anode material in commerce is a carbon-based material, but its theoretical specific capacity is only 372 mAh / g, which is relatively low. In contrast, the silicon-based material has a theoretical specific capacity of 4200 mAh / g, which is more than 10 times that of the carbon-based material. However, after multiple charge-discharge cycles, the particles of pure silicon material will be pulverized, seriously affecting the battery performance. The silicon-carbon anode material combines the advantages of both, with a relatively stable material structure and a high specific capacity.
[0003] However, the silicon-carbon anode also faces some technical problems: 1. Volume expansion: When lithium ions are inserted into the anode material, the material will expand in volume, resulting in deformation and rupture of the electrode material; 2. Electrolyte corrosion: Silicon elements have strong corrosiveness to common organic electrolytes, which will cause the decomposition of the electrolyte, further affecting the performance stability of the battery. The corrosion problem needs to be solved to ensure the long-term stable operation of the battery; 3. Difficult charge transfer: During the charge-discharge process of silicon, the charge transfer speed is slow, which will lead to low charge-discharge efficiency. The silicon-carbon composite can improve this situation to a certain extent. The conductivity is positively correlated with the carbon content. If the carbon content is too high, the specific capacity of the silicon-carbon material will be reduced. Summary of the Invention
[0004] The main object of the present invention is to provide a carbon aerogel composite lithium battery anode and a preparation method thereof. The present invention uses a template material and an oxidant to form a fibrous complex, and forms a hydrogel through the monomer material under the action of the oxidant. Subsequently, a porous structure carbon aerogel is prepared by mixing active substances and freeze-drying. The carbon aerogel can serve as an attachment skeleton for the active substances, and is further carbonized to obtain a carbon aerogel composite material. The structure of the aerogel consists of carbon nanotubes. This carbon aerogel composite material has a porous structure and a conductive network constructed by carbon nanotubes. These characteristics can improve the conductivity of the anode and buffer the volume expansion of the active substances. The porous structure helps to accommodate more electrolyte, thus better soaking the anode, reducing the transmission distance of lithium ions. This design can improve the capacity and cycle life of the anode and reduce the damage to the battery structure caused by volume expansion, effectively solving the problems in the background art.
[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing a negative electrode of a carbon aerogel composite lithium battery, comprising the following steps:
[0007] S1. Dissolve the template and the oxidant in deionized water and stir to form a fibrous complex;
[0008] S2. Add the reactant monomer to the fibrous complex and stir to obtain a hydrogel;
[0009] S3. Add the active material into the hydrogel, stir and mix thoroughly, and let it stand and wash to obtain a hydrogel containing the active material;
[0010] S4. After drying the hydrogel containing the active material in a freeze dryer, an aerogel containing the active material is obtained;
[0011] S5. Under the protection of a protective gas, perform high-temperature heat treatment on the aerogel containing the active material to obtain a carbon aerogel containing the active material.
[0012] Further, the template material in step S1 is selected from at least one of methyl blue, methyl red, ethyl orange, and ethyl red.
[0013] Further, the oxidant in step S1 is selected from at least one of ammonium persulfate, hydrogen peroxide, potassium permanganate, sodium peroxide, perchlorate, and nitric acid.
[0014] Further, the reactant monomer in step S2 is selected from at least one of pyrrole, thiophene, imidazole, thiazole, thiadiazole, and thienoimidazole.
[0015] Further, the mass ratio of the template, the oxidant, and the reactant monomer can be (20-80):1:70, preferably (30-70):1:70, and more preferably (40-50):1:70.
[0016] Further, the concentration of the template is 2-14 mol L-1, preferably 4-12 mol L-1, and more preferably 6-10 mol L-1.
[0017] Further, the active material in step S3 is at least one of artificial graphite, natural graphite, silicon negative electrode, and silicon-carbon negative electrode.
[0018] Further, the detergent in step S3 is a solvent such as deionized water, tap water, and ethanol.
[0019] Further, the protective gas in step S5 is at least one of argon, nitrogen, helium, and argon-hydrogen.
[0020] Furthermore, the mass ratio of the carbon aerogel to the active material is (5 - 30):(70 - 95), preferably (5 - 20):(80 - 95), and more preferably (5 - 10):(90 - 95).
[0021] Furthermore, the stirring process in step S1 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes.
[0022] Furthermore, the stirring process in step S2 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes.
[0023] Furthermore, the stirring and standing time in step S3 is 4 - 24 hours, preferably 12 - 24 hours, and more preferably 20 - 22 hours.
[0024] Furthermore, the calcination heating rate in step S5 is 5 - 30 °C / min, preferably 5 - 20 °C / min, and more preferably 10 - 20 °C / min.
[0025] Furthermore, the calcination temperature in step S5 is 800 - 1200 °C, preferably 900 - 1100 °C, and more preferably 900 - 1000 °C.
[0026] Furthermore, the duration in step S5 is 0.5 - 12 h, preferably 2 - 10 h, and more preferably 4 - 6 h, and it is naturally cooled to room temperature.
[0027] Furthermore, the prepared carbon aerogel composite negative electrode is an electrode for a lithium - ion battery.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] The present invention uses a template material and an oxidant to form a fibrous complex, and forms a hydrogel through the action of a monomer material on the oxidant. Subsequently, a porous - structure carbon aerogel is prepared by mixing an active material and freeze - drying. The carbon aerogel can serve as an attachment skeleton for the active material, and a carbon aerogel composite material is obtained through further carbonization, where the structure of the aerogel is composed of carbon nanotubes. This carbon aerogel composite material has a porous structure and a conductive network constructed by carbon nanotubes. These characteristics can improve the conductive performance of the negative electrode, and can buffer the volume expansion of the active material. The porous structure helps to accommodate more electrolyte, thereby better soaking the negative electrode and reducing the transmission distance of lithium ions. This design can improve the capacity and cycle life of the negative electrode, and reduce the damage to the battery structure caused by volume expansion. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1Flow chart of the preparation method of the carbon aerogel composite anode material of the present invention.
[0031] Figure 2 Charge-discharge performance parameter diagram of the present invention. Detailed implementation manners
[0032] To make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.
[0033] Example 1
[0034] As Figure 1-2 shown, a carbon aerogel composite lithium battery anode and its preparation method include the following steps:
[0035] S1. Dissolve the template and the oxidant in deionized water and stir to form a fibrous complex;
[0036] S2. Add the reactant monomer to the fibrous complex and stir to obtain a hydrogel;
[0037] S3. Add the active material into the hydrogel, stir and mix well, and let it stand and wash to obtain a hydrogel containing the active material;
[0038] S4. After drying the hydrogel containing the active material in a freeze dryer, obtain an aerogel containing the active material;
[0039] S5. Under the protection of a protective gas, perform high-temperature heat treatment on the aerogel containing the active material to obtain a carbon aerogel containing the active material.
[0040] Among them, the template material in step S1 is selected from at least one of methyl blue, methyl red, ethyl orange, and ethyl red.
[0041] Among them, the oxidant in step S1 is selected from at least one of ammonium persulfate, hydrogen peroxide, potassium permanganate, sodium peroxide, perchlorate, and nitric acid.
[0042] Among them, the reactant monomer in step S2 is selected from at least one of pyrrole, thiophene, imidazole, thiazole, thiadiazole, and thiophenoimidazole.
[0043] Among them, the mass ratio of the template, the oxidant, and the reactant monomer can be (20-80):1:70, preferably (30-70):1:70, and more preferably (40-50):1:70.
[0044] Among them, the concentration of the template is 2-14 mol L-1, preferably 4-12 mol L-1, and more preferably 6-10 mol L-1.
[0045] Among them, the active material in the step S3 is at least one of artificial graphite, natural graphite, silicon negative electrode, and silicon-carbon negative electrode.
[0046] Among them, the detergent in the step S3 is a solvent such as deionized water, tap water, ethanol, etc.
[0047] Among them, the protective gas in the step S5 is at least one of argon, nitrogen, helium, and argon-hydrogen.
[0048] Among them, the mass ratio of the carbon aerogel to the active material is (5 - 30):(70 - 95), preferably (5 - 20):(80 - 95), and more preferably (5 - 10):(90 - 95).
[0049] Among them, the stirring process in the step S1 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes.
[0050] Among them, the stirring process in the step S2 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes.
[0051] Among them, the stirring and standing time in the step S3 is 4 - 24 hours, preferably 12 - 24 hours, and more preferably 20 - 22 hours.
[0052] Among them, the calcination heating rate in the step S5 is 5 - 30 °C / min, preferably 5 - 20 °C / min, and more preferably 10 - 20 °C / min.
[0053] Among them, the calcination temperature in the step S5 is 800 - 1200 °C, preferably 900 - 1100 °C, and more preferably 900 - 1000 °C.
[0054] Among them, the duration in the step S5 is 0.5 - 12 h, preferably 2 - 10 h, and more preferably 4 - 6 h, and it is naturally cooled to room temperature.
[0055] Among them, the prepared carbon aerogel composite negative electrode is a lithium-ion battery electrode.
[0056] Example Two
[0057] Refer to Figure 1 , the preparation method of the carbon aerogel composite negative electrode material in this example includes the following steps:
[0058] S1: Dissolve methylene blue and ammonium persulfate in deionized water, adjust the concentration of methylene blue to 8 mol / L, and the mass ratio of methylene blue to ammonium persulfate is 50:1, and stir for 30 minutes to obtain a fibrous complex.
[0059] S2: Add pyrrole monomer into the fibrous complex. The mass ratio of methylene blue, ammonium persulfate to pyrrole is 50:1:70. Stir for 30 minutes to obtain a hydrogel.
[0060] S3: Add silicon carbide material into the hydrogel and stir to mix. Let it stand for 20 h, and wash with deionized water to obtain a hydrogel containing silicon carbide.
[0061] S4: Put the hydrogel containing silicon carbide into a freeze dryer for drying to obtain an aerogel containing silicon carbide.
[0062] S5: Under the protection of nitrogen, heat the aerogel containing silicon carbide to 900 °C at a rate of 20 °C / min, hold for 6 h, and then naturally cool to room temperature to obtain a carbon aerogel composite silicon carbide negative electrode.
[0063] Use an LIR2032 button cell case to test the button cell, adopting an aqueous formula. Carbon aerogel composite silicon carbide negative electrode: SP: CMC: SBR = 94:1.5:1.5:3.
[0064] Example 3
[0065] S1: Dissolve methylene blue and hydrogen peroxide in deionized water. Adjust the concentration of methylene blue to 8 mol / L. The mass ratio of methylene blue to hydrogen peroxide is 50:1. Stir for 30 minutes to obtain a fibrous complex.
[0066] S2: Add pyrrole monomer into the fibrous complex. The mass ratio of methylene blue, hydrogen peroxide to pyrrole is 50:1:70. Stir for 30 minutes to obtain a hydrogel.
[0067] S3: Add silicon carbide into the hydrogel and stir to mix. Let it stand for 20 h, and wash with deionized water to obtain a hydrogel containing silicon carbide.
[0068] S4: Put the hydrogel containing silicon carbide into a freeze dryer for drying to obtain an aerogel containing silicon carbide.
[0069] S5: Under the protection of nitrogen, heat the aerogel containing silicon carbide to 900 °C at a rate of 20 °C / min, hold for 6 h, and then naturally cool to room temperature to obtain a carbon aerogel composite silicon carbide negative electrode.
[0070] Example 4
[0071] S1: Dissolve methylene blue and ammonium persulfate in deionized water. Adjust the concentration of methylene blue to 12 mol / L. The mass ratio of methylene blue to ammonium persulfate is 50:1. Stir for 30 minutes to obtain a fibrous complex.
[0072] S2: Add pyrrole monomer into the fibrous complex. The mass ratio of methylene blue, ammonium persulfate to pyrrole is 50:1:70. Stir for 30 minutes to obtain a hydrogel.
[0073] S3: Add silicon carbide into the hydrogel, stir and mix, let it stand for 20 h, and wash with deionized water to obtain a hydrogel containing silicon carbide.
[0074] S4: Put the hydrogel containing silicon carbide into a freeze dryer for drying to obtain an aerogel containing silicon carbide.
[0075] S5: Under the protection of nitrogen, heat the aerogel containing silicon carbide to 900 °C at a rate of 20 °C / min, keep it at this temperature for 6 h, and then naturally cool it to room temperature to obtain a carbon aerogel composite silicon carbide negative electrode.
[0076] Example 5
[0077] S1: Dissolve methylene blue and ammonium persulfate in deionized water, adjust the concentration of methylene blue to 8 mol / L, and the mass ratio of methylene blue to ammonium persulfate is 50:1. Stir for 30 minutes to obtain a fibrous complex.
[0078] S2: Add thiophene monomer into the fibrous complex, and the mass ratio of methylene blue, ammonium persulfate to thiophene is 50:1:70. Stir for 30 minutes to obtain a hydrogel.
[0079] S3: Add silicon carbide into the hydrogel, stir and mix, let it stand for 20 h, and wash with deionized water to obtain a hydrogel containing silicon carbide.
[0080] S4: Put the hydrogel containing silicon carbide into a freeze dryer for drying to obtain an aerogel containing silicon carbide.
[0081] S5: Under the protection of nitrogen, heat the aerogel containing silicon carbide to 900 °C at a rate of 20 °C / min, keep it at this temperature for 6 h, and then naturally cool it to room temperature to obtain a carbon aerogel composite silicon carbide negative electrode.
[0082] Example 6
[0083] S1: Dissolve methylene blue and ammonium persulfate in deionized water, adjust the concentration of methylene blue to 8 mol / L, and the mass ratio of methylene blue to ammonium persulfate is 50:1. Stir for 30 minutes to obtain a fibrous complex.
[0084] S2: Add pyrrole monomer into the fibrous complex, and the mass ratio of methylene blue, ammonium persulfate to pyrrole is 50:1:70. Stir for 30 minutes to obtain a hydrogel.
[0085] S3: Add silicon carbide into the hydrogel, stir and mix, let it stand for 20 h, and wash with deionized water to obtain a hydrogel containing silicon carbide.
[0086] S4: Put the hydrogel containing silicon carbide into a freeze dryer for drying to obtain an aerogel containing silicon carbide.
[0087] S5: Under the protection of nitrogen, heat the aerogel containing silicon carbide to 1000 °C at a rate of 20 °C / min, hold for 6 h, and then naturally cool to room temperature to obtain a carbon aerogel composite silicon carbide negative electrode.
[0088] It should be noted that the present invention is a carbon aerogel composite lithium battery negative electrode and its preparation method. The materials in the present invention are all materials known to those skilled in the art, and their material characteristics can be obtained by those skilled in the art through technical manuals or by conventional experimental methods.
[0089] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.
Claims
1. A preparation method of a carbon aerogel composite lithium battery negative electrode, characterized in that: It includes the following steps: S1. Dissolve the template and the oxidant in deionized water and stir to form a fibrous complex; S2. Add the reactant monomer into the fibrous complex and stir to obtain a hydrogel; S3. Add the active substance into the hydrogel, stir and mix well, and then stand and wash to obtain a hydrogel containing the active substance; S4. Put the hydrogel containing the active substance into a freeze dryer for drying to obtain an aerogel containing the active substance; S5. Under the protection of a protective gas, perform high-temperature heat treatment on the aerogel containing the active substance to obtain a carbon aerogel containing the active substance.
2. The preparation method of the anode of a carbon aerogel composite lithium battery according to claim 1, characterized in that: The template material in step S1 is selected from at least one of methyl blue, methyl red, ethyl orange, and ethyl red. The oxidant in step S1 is selected from at least one of ammonium persulfate, hydrogen peroxide, potassium permanganate, sodium peroxide, perchlorate, and nitric acid. The reactant monomer in step S2 is selected from at least one of pyrrole, thiophene, imidazole, thiazole, thiadiazole, and thiophenoimidazole.
3. A method for preparing a negative electrode of a carbon aerogel composite lithium battery according to claim 1, characterized in that: The mass ratio of the template, the oxidant, and the reactant monomer can be (20 - 80):1:70, preferably (30 - 70):1:70, and more preferably (40 - 50):1:
70.
4. A method for preparing a negative electrode of a carbon aerogel composite lithium battery according to claim 1, characterized in that: The concentration of the template is 2 - 14 mol / L, preferably 4 - 12 mol / L, and more preferably 6 - 10 mol / L.
5. A method for preparing a negative electrode of a carbon aerogel composite lithium battery according to claim 1, characterized in that: The active substance in step S3 is at least one of artificial graphite, natural graphite, silicon negative electrode, and silicon-carbon negative electrode. The detergent in step S3 is a solvent such as deionized water, tap water, and ethanol.
6. The preparation method of a carbon aerogel composite lithium battery anode according to claim 1, characterized in that: The protective gas in step S5 is at least one of argon, nitrogen, helium, and argon-hydrogen.
7. A method for preparing a negative electrode of a carbon aerogel composite lithium battery according to claim 1, characterized in that: The mass ratio of the carbon aerogel to the active substance is (5 - 30):(70 - 95), preferably (5 - 20):(80 - 95), and more preferably (5 - 10):(90 - 95).
8. A method for preparing a carbon aerogel composite lithium battery anode according to claim 1, characterized in that: The stirring process in step S1 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes. The stirring process in step S2 is 5 - 120 minutes, preferably 5 - 60 minutes, and more preferably 20 - 30 minutes. The stirring and standing time in step S3 is 4 - 24 hours, preferably 12 - 24 hours, and more preferably 20 - 22 hours.
9. The preparation method of a carbon aerogel composite lithium battery negative electrode according to claim 1, characterized in that: The calcination heating rate in step S5 is 5 - 30 °C / min, preferably 5 - 20 °C / min, and more preferably 10 - 20 °C / min. The calcination temperature in step S5 is 800 - 1200 °C, preferably 900 - 1100 °C, and more preferably 900 - 1000 °C. The duration in step S5 is 0.5 - 12 h, preferably 2 - 10 h, and more preferably 4 - 6 h, and it is naturally cooled to room temperature.
10. A method for preparing a negative electrode of a carbon aerogel composite lithium battery according to any one of claims 1-9, characterized in that: The prepared carbon aerogel composite negative electrode is an electrode for a lithium-ion battery.