Preparation method of anti-aging lithium battery electrode material
By forming a hydrophobic covalent bonding layer and constructing a three-dimensional conductive network on the surface of silicon particles, combined with a nitrogen-doped carbon coating layer and pre-lithiation treatment, the volume expansion and side reaction problems of silicon-based anode materials for lithium batteries were solved, resulting in electrode materials with high energy density and long lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YIDING SHANGHAI INFORMATION TECH CO LTD
- Filing Date
- 2025-07-16
- Publication Date
- 2026-05-12
AI Technical Summary
Existing silicon-based anode materials for lithium batteries suffer from problems such as high volume expansion rate, severe side reactions with electrolyte, and low electronic conductivity during charge and discharge, leading to electrode cracking, active material shedding, and capacity decay. Traditional improvement technologies are difficult to effectively solve these problems.
By forming a hydrophobic covalent bonded layer on the surface of silicon particles, combining a highly polar solvent and a polymer stabilizer to achieve uniform dissociation of graphene, a three-dimensional conductive network is constructed. A ball milling process is used to form a point-to-surface contact structure, a nitrogen-doped carbon coating layer is generated by vapor deposition, and pre-lithiation treatment is performed to optimize the electron transport path and ion adsorption capacity.
It significantly improves the cycle life and energy density of lithium batteries, suppresses side reactions and volume expansion, and maintains the stability and high capacity of the electrode structure.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of electrode materials, and relates to a preparation method of an anti-aging lithium battery electrode material. BACKGROUND
[0002] As a core energy storage device, the improvement of the energy density and cycle life of a lithium ion battery is always a key requirement of the industry. A silicon-based negative electrode material is considered as an ideal candidate due to its high theoretical specific capacity, but its practical application is limited by the following problems: first, the volume expansion rate during charging and discharging is more than 300%, which leads to electrode cracking and active material shedding; second, continuous side reactions between the silicon surface and the electrolyte generate a too thick SEI film, consume active lithium and exacerbate capacity decay; third, the electronic conductivity of silicon itself is low, and traditional conductive additives such as carbon black are difficult to build an efficient conductive network, especially under high load, the performance decay is significant.
[0003] In the existing improvement technology, nano-silicon particles can alleviate volume expansion, but are prone to agglomeration and have high preparation cost; the composite with materials such as graphene can improve the conductivity, but the interfacial bonding force is weak and phase separation is prone to occur during long-term cycling; the carbon coating or pre-lithiation technology can inhibit the thickening of the SEI film or compensate for the loss of lithium, but the uniformity of the carbon layer is difficult to control, and the traditional pre-lithiation method is prone to cause lithium dendrites, which has a safety hazard.
[0004] Therefore, there is an urgent need for a preparation method of an anti-aging lithium battery electrode material. SUMMARY
[0005] The purpose of the present application is to provide a preparation method of an anti-aging lithium battery electrode material, which has good anti-aging performance and electrochemical performance.
[0006] The purpose of the present application can be achieved by the following technical solutions:
[0007] A preparation method of an anti-aging lithium battery electrode material, the specific steps of the preparation method are as follows,
[0008] S1: 5-10 parts by weight of silicon powder is dispersed in 5-10 parts by weight of isopropyl alcohol solution, silane coupling agent KH550 is added, and ultrasonic treatment is carried out at 40-45 DEG C for 1-2 h to obtain dispersion liquid A;
[0009] S2: 3-5 parts by weight of graphene oxide powder is added to 80-100 parts by weight of N-methyl pyrrolidone to make the solid-liquid mass ratio 2-3 mg / mL, 0.3-0.5 parts by weight of dispersant is added, and ultrasonic treatment is carried out under ice bath for 3-4 h to obtain dispersion liquid B;
[0010] S3: Place dispersion A and dispersion B into a ball mill jar with a ball-to-material ratio of (10~15):1. Use zirconia milling balls with a diameter of 5 mm, mill at a speed of 200~300 rpm, and mill for 12~16 h. Wash with ethanol three times and then dry with supercritical CO2 to obtain complex C.
[0011] S4: The composite was placed in a tube furnace and heated to 800 °C in an argon atmosphere. The temperature was then maintained at 800 °C for 2-3 h in a mixed atmosphere of methane, ammonia and carrier gas. The composite was then naturally cooled to room temperature to obtain composite D.
[0012] S5: Mix composite D, conductive carbon black, and PVDF, and coat the mixture onto copper foil with a loading of 1-2 mg / cm³. 2 The sample was vacuum dried at 120℃ for 12 h, and then rolled until the compacted density was 1.6~1.8 g / cm³. 3 The material is then placed in a custom hot press for pre-lithiation treatment to obtain the anti-aging lithium battery electrode material.
[0013] As a preferred embodiment of the present invention, the amount of silane coupling agent KH550 added in S1 is 1 to 3% of the mass of silicon powder.
[0014] In a preferred embodiment of the present invention, the dispersant in S2 is polyvinylpyrrolidone.
[0015] As a preferred embodiment of the present invention, the ultrasonic frequency in S2 is 10~20 kHz and the power is 500~600 W.
[0016] As a preferred technical solution of the present invention, the ball milling method in S3 is to pause for 15 minutes every 1 hour of operation to dissipate heat.
[0017] As a preferred embodiment of the present invention, the supercritical CO2 drying in S3 is carried out at a temperature of 40~48℃ and a pressure of 10~15MPa.
[0018] As a preferred embodiment of the present invention, the heating rate in S4 is 5~10 ℃ / min.
[0019] As a preferred embodiment of the present invention, the volume ratio of the mixture of methane, ammonia and carrier gas in S4 is (3~4):1:10, wherein the carrier gas is argon containing 5% ferrocene by volume.
[0020] In a preferred embodiment of the present invention, in step S5, composite D, conductive carbon black and PVDF are mixed in a mass ratio of (18~20):1:1.
[0021] As a preferred embodiment of the present invention, in the pre-lithiation treatment of S5, the temperature on the lithium foil side is 60~65℃, the temperature on the electrode side is 40~45℃, the pressure is 0.3~0.5 MPa, the time is 1 h, and the thickness of the lithium foil is 50 μm.
[0022] This invention reconstructs the interfacial stability of electrode materials at the molecular level. A dense covalently bonded layer is formed on the surface of silicon particles using a silane coupling agent. Its organic hydrophobic properties retain the high capacity of silicon while effectively blocking the physical penetration and chemical erosion of harmful components in the electrolyte, suppressing side reactions. This modification significantly enhances the interfacial compatibility between silicon particles and graphene, eliminating phase separation tendencies during the composite process and laying the foundation for subsequent structural assembly. In the graphene dispersion system, the highly polar solvent, in conjunction with the polymeric steric stabilizer, achieves complete dissociation and uniform dispersion of graphene sheets, thoroughly suppressing sheet stacking and constructing a continuous three-dimensional conductive framework. Long polymer chains selectively adsorb and bridge the silicon-graphene interface, significantly reducing the interfacial energy barrier, forming efficient electron transport channels, and greatly weakening the electrode polarization effect.
[0023] Ball milling, through precise energy transfer control, fosters a unique point-to-surface contact topology between silicon particles and graphene. Graphene sheets, acting as a flexible substrate, effectively absorb the mechanical stress generated by silicon volume changes through their elastic deformation, preventing electrode structural cracking and failure. Subsequently, supercritical fluid drying technology is employed to maintain the multi-level porous structure of the composite material at the molecular level, overcoming the pore collapse problem caused by traditional drying methods. The constructed three-dimensional network possesses dual functions: firstly, it significantly shortens the lithium-ion solid-phase diffusion distance, endowing the material with excellent high-rate performance; secondly, it forms capillary penetration channels for the electrolyte, achieving a dynamic balance of ion concentration at the electrode-electrolyte interface, fundamentally reducing interfacial impedance and enabling the material to possess adaptive buffering capabilities.
[0024] During the vapor deposition process, a nitrogen-doped carbon composite coating layer is constructed on the material surface through precise ratio of reactant gases and control of pyrolysis kinetics, and under the catalysis of iron, a physical barrier is achieved to prevent direct contact between active materials and electrolyte, thus inhibiting the continuous generation of inactive phases. The defect sites introduced in the nitrogen-doped carbon form lithium-ion enrichment regions, accelerating interfacial charge transfer. Its intrinsic mechanical strength, together with the graphene network, constitutes a two-level buffer system to ensure structural integrity.
[0025] The pre-lithiation process achieves gradient diffusion and embedding of lithium metal through thermodynamic parameter matching: the coordinated control of temperature and pressure fields ensures both the directional compensation of active lithium to offset initial losses and the suppression of lithium dendrite nucleation growth through pressure confinement, thus ensuring a balance between high energy density and long cycle life.
[0026] Through a four-dimensional synergy of surface hydrophobic modification, a three-dimensional conductive network, nitrogen-doped carbon coating, and pre-lithiation compensation, the surface-modified layer chemically suppresses side reactions, the three-dimensional conductive network optimizes electron transport paths, the nitrogen-doped carbon coating enhances ion adsorption capacity, and pre-lithiation technology compensates for capacity loss. Under the synergistic effect of these four elements, the electrode maintains structural stability during long-term cycling, and its capacity retention remains at a high level after 200 cycles, significantly outperforming traditional silicon-based electrodes. The fabrication method of this invention achieves a balance between high energy density and long lifespan in high-energy-density lithium batteries through multi-scale structural design and process optimization.
[0027] The beneficial effects of this invention are:
[0028] This invention utilizes a silane coupling agent to form a hydrophobic covalent bond layer on the surface of silicon particles, effectively blocking electrolyte erosion and enhancing interfacial bonding with graphene, thus inhibiting agglomeration during the composite process. It combines a highly polar solvent with a polymeric stabilizer to achieve uniform dissociation of graphene, constructing a three-dimensional conductive network. The polymeric chains bridge the interface, reducing charge transport resistance. Ball milling forms a point-to-surface contact structure between silicon and graphene. The flexible graphene substrate buffers volume expansion stress, and supercritical drying maintains the porous structure to shorten the lithium-ion diffusion path.
[0029] A nitrogen-doped carbon coating layer is generated by vapor deposition, which physically blocks electrolyte contact and introduces defect sites to accelerate ion adsorption, forming a two-stage buffer system with the graphene network. The pre-lithiation process achieves lithium metal gradient intercalation through thermodynamic control, compensating for the capacity loss in the first cycle while suppressing lithium dendrites. Ultimately, the electrode material exhibits both high capacity and long cycle life, significantly outperforming traditional silicon-based materials. Detailed Implementation
[0030] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.
[0031] Example 1
[0032] A method for preparing an anti-aging lithium battery electrode material, the specific steps of which are as follows:
[0033] S1: Disperse 8 parts by weight of silicon powder in 8 parts by weight of isopropanol solution, add 2% by weight of silicon powder of silane coupling agent KH550, and sonicate at 43 °C for 1.5 h to obtain dispersion A;
[0034] S2: Add 4 parts by weight of graphene oxide powder to 90 parts by weight of N-methylpyrrolidone to make the solid-liquid mass ratio 2.5 mg / mL, add 0.4 parts by weight of polyvinylpyrrolidone, and sonicate in an ice bath for 3.5 h at an ultrasonic frequency of 15 kHz and a power of 550 W to obtain dispersion B.
[0035] S3: Dispersion A and dispersion B were placed in a ball mill jar with a ball-to-material ratio of 12:1. Zirconia milling balls with a diameter of 5 mm were used. The milling method was to pause for 15 minutes every 1 hour to dissipate heat. The milling speed was 250 rpm and the milling time was 14 hours. The mixture was washed three times with ethanol and then dried by supercritical CO2 at a temperature of 45℃ and a pressure of 12 MPa to obtain composite C.
[0036] S4: The composite was placed in a tube furnace and heated to 800 °C in an argon atmosphere at a rate of 5 °C / min. It was then held at 800 °C for 2.5 h in a mixed atmosphere of methane, ammonia, and carrier gas with a volume ratio of 3.5:1:10. The carrier gas was argon containing 5% ferrocene by volume. The mixture was then naturally cooled to room temperature to obtain composite D.
[0037] S5: Composite D, conductive carbon black, and PVDF are mixed at a mass ratio of 19:1:1 and coated onto copper foil with a loading of 1.5 mg / cm³. 2 It was vacuum dried at 120 °C for 12 h, and then rolled until the compacted density was 1.7 g / cm³. 3 The material was then placed in a custom hot press for pre-lithiation treatment. The temperature on the lithium foil side was 63 °C, the temperature on the electrode side was 43 °C, the pressure was 0.4 MPa, the time was 1 h, and the lithium foil thickness was 50 μm, thus obtaining the anti-aging lithium battery electrode material.
[0038] Example 2
[0039] A method for preparing an anti-aging lithium battery electrode material, the specific steps of which are as follows:
[0040] S1: Disperse 5 parts by weight of silicon powder in 5 parts by weight of isopropanol solution, add 1% by weight of silicon powder of silane coupling agent KH550, and sonicate at 40 °C for 1 h to obtain dispersion A;
[0041] S2: Add 3 parts by weight of graphene oxide powder to 80 parts by weight of N-methylpyrrolidone to make the solid-liquid mass ratio 2 mg / mL, add 0.3 parts by weight of polyvinylpyrrolidone, and sonicate in an ice bath for 3 h at a frequency of 10 kHz and a power of 500 W to obtain dispersion B.
[0042] S3: Dispersion A and dispersion B were placed in a ball mill jar with a ball-to-material ratio of 10:1. Zirconia milling balls with a diameter of 5 mm were used. The milling method was to pause for 15 minutes every 1 hour to dissipate heat. The milling speed was 200 rpm and the milling time was 12 hours. The mixture was washed three times with ethanol and then dried by supercritical CO2 at a temperature of 40 °C and a pressure of 10 MPa to obtain composite C.
[0043] S4: The composite was placed in a tube furnace and heated to 800 °C in an argon atmosphere at a rate of 5 °C / min. It was then held at 800 °C for 2 h in a mixed atmosphere of methane, ammonia and carrier gas with a volume ratio of 3:1:10. The carrier gas was argon containing 5% ferrocene by volume. The mixture was then naturally cooled to room temperature to obtain composite D.
[0044] S5: Mix composite D, conductive carbon black, and PVDF at a mass ratio of 18:1:1, and coat the mixture onto copper foil with a loading of 1 mg / cm³. 2 It was vacuum dried at 120 °C for 12 h, and then rolled until the compacted density was 1.6 g / cm³. 3 The material is then placed in a custom hot press for pre-lithiation treatment. The temperature on the lithium foil side is 60 °C, the temperature on the electrode side is 40 °C, the pressure is 0.3 MPa, the time is 1 h, and the lithium foil thickness is 50 μm, thus obtaining the anti-aging lithium battery electrode material.
[0045] Example 3
[0046] A method for preparing an anti-aging lithium battery electrode material, the specific steps of which are as follows:
[0047] S1: Disperse 10 parts by weight of silicon powder in 10 parts by weight of isopropanol solution, add 3% by weight of silicon powder of silane coupling agent KH550, and sonicate at 45 °C for 2 h to obtain dispersion A;
[0048] S2: Add 5 parts by weight of graphene oxide powder to 100 parts by weight of N-methylpyrrolidone to make the solid-liquid mass ratio 3 mg / mL, add 0.5 parts by weight of polyvinylpyrrolidone, and sonicate in an ice bath for 4 h at a frequency of 20 kHz and a power of 600 W to obtain dispersion B.
[0049] S3: Dispersion A and dispersion B were placed in a ball mill jar with a ball-to-material ratio of 15:1. Zirconia milling balls with a diameter of 5 mm were used. The milling method was to pause for 15 minutes every 1 hour to dissipate heat. The milling speed was 300 rpm and the milling time was 16 hours. The mixture was washed three times with ethanol and then dried by supercritical CO2 at a temperature of 48 ℃ and a pressure of 15 MPa to obtain composite C.
[0050] S4: The composite was placed in a tube furnace and heated to 800 °C in an argon atmosphere at a rate of 10 °C / min. It was then held at 800 °C for 3 h in a mixed atmosphere of methane, ammonia and carrier gas with a volume ratio of 4:1:10. The carrier gas was argon containing 5% ferrocene by volume. The mixture was then naturally cooled to room temperature to obtain composite D.
[0051] S5: Mix composite D, conductive carbon black, and PVDF at a mass ratio of 20:1:1, and coat the mixture onto copper foil with a loading of 2 mg / cm³. 2 It was vacuum dried at 120 °C for 12 h, and then rolled until the compacted density was 1.8 g / cm³. 3 The material is then placed in a custom hot press for pre-lithiation treatment. The lithium foil side temperature is 65 ℃, the electrode side temperature is 45 ℃, the pressure is 0.5 MPa, the time is 1 h, and the lithium foil thickness is 50 μm, thus obtaining the anti-aging lithium battery electrode material.
[0052] Comparative Example 1
[0053] The preparation method of the anti-aging lithium battery electrode material does not include the silane coupling agent KH550, and the remaining steps are the same as in Example 1.
[0054] Comparative Example 2
[0055] The preparation method of the anti-aging lithium battery electrode material does not include polyvinylpyrrolidone, and the remaining steps are the same as in Example 1.
[0056] Comparative Example 3
[0057] In the preparation method of anti-aging lithium battery electrode material, supercritical CO2 drying is replaced with ordinary vacuum drying, and the parameters are set to 60℃, -0.1MPa, 12h. The remaining steps are the same as in Example 1.
[0058] Comparative Example 4
[0059] The preparation method of the anti-aging lithium battery electrode material does not involve the addition of ammonia gas, and the remaining steps are the same as in Example 1.
[0060] Comparative Example 5
[0061] The preparation method of the anti-aging lithium battery electrode material does not include methane, and the remaining steps are the same as in Example 1.
[0062] Comparative Example 6
[0063] In the preparation method of the anti-aging lithium battery electrode material, ferrocene is not added to the carrier gas, and the remaining steps are the same as in Example 1.
[0064] Electrochemical performance testing
[0065] Using lithium metal as the counter electrode, 1M LiPF6 / EC:DMC:EMC (volume ratio 1:1:1) as the electrolyte, and Celgard 2400 as the separator, a CR2032 coin cell was assembled in an argon glove box. The first charge and discharge was performed at a rate of 0.1C, and the first coulombic efficiency (ICE) was recorded.
[0066] Volume expansion rate test
[0067] The change in electrode thickness before and after cycling was measured using a micrometer, and the volume expansion rate was calculated as (thickness after cycling - thickness before cycling) / thickness before cycling × 100%).
[0068] The specific experimental results are summarized in the table below.
[0069]
[0070] As can be seen from the examples and comparative data, the electrode material of the present invention has good anti-aging properties and electrochemical properties.
[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are still within the scope of the present invention.
Claims
1. A method for preparing an anti-aging lithium battery electrode material, characterized in that, The specific steps of the preparation method are as follows: S1: Disperse 5-10 parts by weight of silicon powder in 5-10 parts by weight of isopropanol solution, add silane coupling agent KH550, and sonicate at 40-45 ℃ for 1-2 h to obtain dispersion A; S2: Add 3-5 parts by weight of graphene oxide powder to 80-100 parts by weight of N-methylpyrrolidone to make the solid-liquid mass ratio 2-3 mg / mL, add 0.3-0.5 parts by weight of dispersant, and sonicate in an ice bath for 3-4 h to obtain dispersion B; S3: Place dispersion A and dispersion B into a ball mill jar with a ball-to-material ratio of (10~15):
1. Use zirconia milling balls with a diameter of 5 mm, mill at a speed of 200~300 rpm, and mill for 12~16 h. Wash with ethanol three times and then dry with supercritical CO2 to obtain complex C. S4: The composite was placed in a tube furnace and heated to 800 °C in an argon atmosphere. The temperature was then maintained at 800 °C for 2-3 h in a mixed atmosphere of methane, ammonia and carrier gas. The composite was then naturally cooled to room temperature to obtain composite D. S5: Mix composite D, conductive carbon black, and PVDF, and coat the mixture onto copper foil with a loading of 1-2 mg / cm³. 2 The sample was vacuum dried at 120 °C for 12 h, and then rolled to a compaction density of 1.6~1.8 g / cm³. 3 The material is then placed in a custom hot press for pre-lithiation treatment to obtain the anti-aging lithium battery electrode material. The dispersant in S2 is polyvinylpyrrolidone; The supercritical CO2 drying in S3 is carried out at a temperature of 40~48 ℃ and a pressure of 10~15 MPa. The volume ratio of the mixture of methane, ammonia and carrier gas in S4 is (3~4):1:10, wherein the carrier gas is argon containing 5% ferrocene by volume.
2. The method for preparing an anti-aging lithium battery electrode material according to claim 1, characterized in that, The amount of silane coupling agent KH550 added in S1 is 1-3% of the mass of silicon powder.
3. The method for preparing an anti-aging lithium battery electrode material according to claim 1, characterized in that, The ball milling method in S3 involves pausing for 15 minutes every 1 hour of operation to dissipate heat.
4. The method for preparing an anti-aging lithium battery electrode material according to claim 1, characterized in that, The heating rate in S4 is 5~10 ℃ / min.
5. The method for preparing an anti-aging lithium battery electrode material according to claim 1, characterized in that, In step S5, composite D, conductive carbon black, and PVDF are mixed in a mass ratio of (18~20):1:
1.
6. The method for preparing an anti-aging lithium battery electrode material according to claim 1, characterized in that, In the pre-lithiation treatment of S5, the temperature on the lithium foil side is 60~65 ℃, the temperature on the electrode side is 40~45 ℃, the pressure is 0.3~0.5 MPa, the time is 1 h, and the lithium foil thickness is 50 μm.