CN107069016B - Silicon-carbon negative electrode material and preparation method thereof - Google Patents
Silicon-carbon negative electrode material and preparation method thereof Download PDFInfo
- Publication number
- CN107069016B CN107069016B CN201710270679.XA CN201710270679A CN107069016B CN 107069016 B CN107069016 B CN 107069016B CN 201710270679 A CN201710270679 A CN 201710270679A CN 107069016 B CN107069016 B CN 107069016B
- Authority
- CN
- China
- Prior art keywords
- silicon
- particles
- nano
- conductive
- carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention belongs to the field of energy storage research, and particularly relates to a silicon-carbon anode material which comprises a core structure and a shell structure, wherein the core structure is of a secondary particle structure formed by uniformly dispersing nano primary particles in a conductive agent and then tightly stacking the nano primary particles, and the nano primary particles comprise nano silicon-based particles; and conductive networks are distributed among the nano silicon-based particles, among the conductive agents and between the nano silicon-based particles and the conductive agents, and the conductive networks are tightly connected with the nano silicon-based particles and the conductive agents, so that the silicon-carbon negative electrode material is ensured to have excellent electrochemical performance.
Description
Technical Field
The invention belongs to the technical field of energy storage materials, and particularly relates to a silicon-carbon negative electrode material and a preparation method thereof.
Background
Since the birth of the lithium ion battery, the lithium ion battery brings revolutionary changes to the field of energy storage due to the advantages of large specific energy, high working voltage, small self-discharge rate, small volume, light weight and the like, and is widely applied to various portable electronic devices and electric automobiles. However, with the improvement of living standard of people, higher user experience puts higher requirements on the lithium ion battery: lighter weight, longer service life, etc.; in order to solve the above problems, it is necessary to find a new electrode material having more excellent properties.
The current commercialized lithium ion battery cathode material is mainly graphite, but the theoretical capacity of the lithium ion battery cathode material is only 372mAh g-1The urgent needs of users cannot be met; therefore, the development of a negative electrode material having a higher specific capacity is imminent. Silicon materials have been attracting attention as negative electrode materials for lithium ion batteries. The theoretical capacity is 4200mAh g-1The material is more than 10 times of the commercial graphite capacity, and has the advantages of low lithium intercalation potential, low atomic weight, high energy density, low price, environmental friendliness and the like, so that the material is one of the optimal choices of a new generation of high-capacity negative electrode material.
However, the silicon material has poor conductivity and is easy to cause structural damage and mechanical crushing due to large volume expansion in the charging and discharging processes, so that the cycle performance of the silicon material is quickly attenuated, and the wider application of the silicon material is limited. In order to solve the problems, the prior art mainly comprises the steps of nano-crystallizing silicon particles, adding a conductive material with excellent conductive performance into the silicon-based material particles and the like so as to improve the conductive performance of the whole particles of the silicon-based material, and simultaneously solving the problems of mechanical crushing of the silicon-based material in the charging and discharging processes of the material.
However, silicon-based particles with nano structures are extremely easy to agglomerate and have high dispersion difficulty; the commonly used conductive agent materials are generally small in size (nanometer), large in specific surface area and difficult to disperse. However, in order to maximize the conductive effect of the conductive agent and to prepare a silicon-based secondary particle material with better performance, it is necessary to ensure that the nano silicon-based particles and the conductive agent are uniformly dispersed. Meanwhile, the bonding force between the silicon-based material with the nano structure and the conductive agent is weak, and the silicon-based material and the conductive agent are easily disconnected in the volume expansion process, so that the electrochemical performance of the silicon-carbon material is influenced.
In view of the above, there is a need for a silicon-carbon negative electrode material and a preparation method thereof, which can uniformly disperse two materials (nano silicon-based particles and conductive agent) with high dispersion difficulty, and ensure that the two materials are tightly connected together, thereby preparing a silicon-carbon negative electrode material with excellent performance.
Disclosure of Invention
One of the objects of the present invention is: aiming at the defects of the prior art, the provided silicon-carbon cathode material can uniformly disperse two materials (nano silicon-based particles and conductive agents) with larger dispersion difficulty, and simultaneously ensures that the two materials are tightly connected together, so that the silicon-carbon cathode material with excellent performance is prepared, and the silicon-carbon cathode material is ensured to have excellent electrochemical performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
the silicon-carbon anode material is of a secondary particle structure obtained by tightly packing primary particles, wherein the secondary particles comprise the primary particles and a conductive agent component, and the primary particles comprise nano silicon-based particles; conductive networks are distributed among the nano silicon-based particles, among the conductive agents and between the nano silicon-based particles and the conductive agents, and the conductive networks are tightly connected with the nano silicon-based particles and the conductive agent components.
As an improvement of the silicon-carbon cathode material, the conductive network is obtained by carbonizing a high polymer material; before carbonization, the high polymer material is uniformly distributed between the nano silicon-based particles and the conductive agent, and the nano silicon-based particles, the conductive agent and the nano silicon-based particles and the conductive agent are tightly bonded together.
As an improvement of the silicon-carbon negative electrode material, the macromolecule is obtained by in-situ polymerization of macromolecule monomers.
As an improvement of the silicon-carbon anode material, the nano silicon-based particles are simple substance silicon particles or/and silicon oxide particles; the conductive agent component comprises at least one of conductive carbon black, super conductive particles, Ketjen black, carbon nano tubes, graphene, acetylene black and a conductive network obtained by carbonizing a high polymer material; the primary particles may further include non-nano silicon-based anode particles; the non-nano silicon-based negative electrode particles are at least one of natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, hard carbon, petroleum coke, carbon fibers, pyrolytic resin carbon, lithium carbonate, a tin-based negative electrode material, transition metal nitride, a tin-based alloy, a germanium-based alloy, an aluminum-based alloy, an antimony-based alloy and a magnesium-based alloy;
the invention also discloses a preparation method of the silicon-carbon cathode material, which is characterized by mainly comprising the following steps of:
step 1, kneading: mixing and kneading the primary nano-particles and the polymer monomer to uniformly disperse the polymer monomer on the surface of the primary nano-particles;
step 2, polymerization reaction: adding an initiator into the product obtained in the step (1) to promote a polymerization reaction of a polymerization monomer, wherein the generated polymer network structure is coated on the surface of the primary nano-particles;
step 3, pelletizing: selecting the product obtained in the step (2) which has a certain degree of polymerization reaction, and pelletizing to obtain secondary particles;
step 4, preparing a silicon-carbon negative electrode: and (4) coating and carbonizing the product obtained in the step (3) to obtain the finished silicon-carbon cathode material.
The shell structure is a coating layer commonly used for cathode materials and is mainly obtained by coating and carbonizing materials such as asphalt and the like, so that the invention is not explained in detail.
As an improvement of the preparation method of the silicon-carbon negative electrode material, in the step 1, the polymer monomer comprises acrylates, methacrylates, styrene, acrylonitrile, methacrylonitrile, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, divinylbenzene, trimethylolpropane trimethacrylate, methyl methacrylate, N-dimethylacrylamide, N-acryloyl morpholine, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl N-acrylate, cyclohexyl 2-acrylate, dodecyl acrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, neopentyl glycol diacrylate, 1, 6-hexanediol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, ethylene, At least one of ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol acrylate, bis-trihydroxypropane tetraacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, propoxylated glycerol triacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate; the initiator in the step 2 is at least one of cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, ditert-butyl peroxide, dibenzoyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.
As an improvement of the preparation method of the silicon-carbon anode material, the nano primary particles in the step 1 comprise nano silicon-based particles; the nano primary particles can also comprise non-nano silicon-based negative electrode particles, and the non-nano silicon-based negative electrode particles are at least one of natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, hard carbon, petroleum coke, carbon fibers, pyrolytic resin carbon, lithium carbonate, a tin-based negative electrode material, transition metal nitride, a tin-based alloy, a germanium-based alloy, an aluminum-based alloy, an antimony-based alloy and a magnesium-based alloy; during the kneading reaction, a high molecular polymer, a carbon source component, a conductive agent component or/and a solvent component can be added, wherein the high molecular polymer comprises at least one of polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC) and polyacrylonitrile, the carbon source component comprises glucose, sucrose, soluble starch, cyclodextrin, furfural, sucrose, glucose, corn starch, tapioca starch, wheat starch, cellulose, polyvinyl alcohol, polyethylene glycol, polyethylene wax, phenolic resin, vinyl pyrrolidone, epoxy resin, polyvinyl chloride, polyalditol, furan resin, urea-formaldehyde resin, polymethyl methacrylate, polyvinylidene fluoride or polyacrylonitrile, petroleum coke, oil-based needle coke and coal-based needle coke, and the conductive agent component comprises at least one of conductive carbon black, conductive carbon, conductive agent component or/and solvent component, At least one of super conductive particles, Ketjen black, carbon nanotubes, graphene and acetylene black, and at least one of water, alcohols, ketones, alkanes, esters, aromatics, N-methylpyrrolidone, dimethylformamide, diethylformamide, dimethylsulfoxide and tetrahydrofuran.
As an improvement of the preparation method of the silicon-carbon anode material, the kneading process in the step 1 is as follows: kneading the nano primary particles, the silane coupling agent, the polymer monomer and the solvent 1 to obtain a mixture 1; kneading the conductive agent component, the surfactant and the solvent 2 to obtain a mixture 2; and blending the mixture 1 and the mixture 2 in a blending mode including at least one of kneading, ball milling, sand milling, high-pressure homogenization and high-speed shearing, and dispersing uniformly to obtain precursor slurry.
As an improvement of the preparation method of the silicon-carbon anode material, the polymerization reaction in the step 3 occurs to a certain extent, which means that the polymerization reaction is performed by 10-90%.
As an improvement of the preparation method of the silicon-carbon anode material of the present invention, the sequence of step 2 and step 3 may also be exchanged, that is:
step 2, pelletizing: pelletizing the precursor slurry obtained in the step 1 to obtain secondary particles;
step 3, polymerization reaction: placing the secondary particles obtained in the step (2) in an environment with an initiator to promote a polymerization reaction of a polymerization monomer, and coating the surface of the primary nano particles with a generated polymer network structure; in this case, it is required that the boiling point of the polymer monomer selected is not lower than the drying temperature used in the pelletization.
As an improvement of the preparation method of the silicon-carbon anode material, the silane coupling agent accounts for 0.01-10% of the mass of the nano silicon substrate, and the solid content of the slurry is not lower than 1%; the surfactant accounts for 0.01-10% of the mass of the conductive agent, and the solid content of the slurry is not lower than 0.5%.
As an improvement of the preparation method of the silicon-carbon negative electrode material, the silane coupling agent is at least one of alkyl silane coupling agent, amino silane coupling agent, alkenyl silane coupling agent, epoxy alkyl silane coupling agent and alkyl acryloxy silane coupling agent; the solvent 1 is at least one of water, alcohols, ketones, alkanes, esters, aromatics, N-methylpyrrolidone, dimethylformamide, diethylformamide, dimethyl sulfoxide and tetrahydrofuran. The surfactant is at least one of a wetting agent, a dispersing agent, a penetrating agent, a solubilizer, a cosolvent and a latent solvent; the solvent 2 is at least one of water, alcohols, ketones, alkanes, esters, aromatics, N-methylpyrrolidone, dimethylformamide, diethylformamide, dimethyl sulfoxide and tetrahydrofuran.
The invention has the advantages that:
1. according to the invention, the high molecular monomer with very low viscosity is used as a reactant for stirring and dispersing, so that the dispersion difficulty can be greatly reduced, and the high molecular monomer is uniformly dispersed on the surface of the primary nano particle;
2. according to the invention, the high-molecular monomer is polymerized in situ and then carbonized to construct the conductive network, so that components in secondary particles such as primary nanoparticles and conductive agent components can be tightly bonded together, and the electrochemical performance of each primary particle can be fully exerted in the circulation process;
3. in the kneading process, the macromolecular monomer and the silane coupling agent can be uniformly coated on the surface of the primary nano particles, so that the dispersion among the primary nano particles is facilitated; similarly, the surface of the conductive agent can be uniformly coated with the surfactant, so that the dispersion among conductive agent particles is facilitated; meanwhile, because the silane coupling agent and the surfactant are dispersed separately in advance, the performances of the silane coupling agent and the surfactant can be maximized, and the use amounts of the silane coupling agent and the surfactant are reduced;
4. by using a kneading process, the dosage of the solvent 1 and the solvent 2 can be minimized under the condition of ensuring uniform dispersion, so that the solid content of the obtained slurry is improved as much as possible; at the moment, the energy consumption during spray drying can be reduced, the production efficiency is improved, and the production cost is reduced; meanwhile, due to the high solid content, the amount of the solvent volatilized from the mist particles is reduced during spray drying (the solvent volatilization process is usually accompanied with the migration of the conductive agent component with lower density from the inside of the particles to the surfaces of the particles, and finally the phenomenon that the conductive agent is unevenly distributed in the secondary particles is caused), so the influence on the distribution of the conductive agent is lower, and the distribution of the conductive agent in the obtained secondary particles is more uniform; the secondary particulate active material has a higher capacity, a lower internal resistance;
Detailed Description
The present invention and its advantageous effects will be described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.
Comparative example, a silicon carbon secondary particulate material having a particle diameter of 10 μm was prepared;
step 1, mixing: elemental silicon with the particle size of 100nm, polymethyl methacrylate, conductive carbon black, tetraethoxysilane, polyvinylpyrrolidone and NMP (solid content is 0.5%) are mixed and stirred for 10 hours to obtain slurry, wherein the mass ratio of the elemental silicon to the polymethyl methacrylate to the conductive carbon black to the tetraethoxysilane to the polyvinylpyrrolidone is 90:4:4.9:1: 0.1.
Step 2, preparing secondary particles: adjusting the spray drying condition to prepare the silicon-carbon secondary particles with the particle diameter of 10 mu m; and then coating and carbonizing to obtain the finished product of the silicon-carbon cathode material.
Example 1 is different from the comparative example in that the present example includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, methyl methacrylate, tetraethoxysilane (the mass ratio is that the simple substance silicon is the methyl methacrylate and the tetraethoxysilane is 90:4:1) and NMP (the solid content is 1 percent), kneading, wherein the revolution is 60 revolutions per minute, and the rotation is 500 revolutions per minute; kneading for 2h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP (the solid content is 0.5%), kneading, revolving at 60 revolutions/min, and rotating at 500 revolutions/min; kneading for 2h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 20 revolutions per minute, and rotating at 300 revolutions per minute; kneading for 2h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
step 4, preparing a silicon-carbon negative electrode: and (4) coating and carbonizing the product obtained in the step (3) to obtain the finished silicon-carbon cathode material.
The rest is the same as that of the comparative example and is not repeated here.
Embodiment 2 is different from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, methyl methacrylate, tetraethoxysilane (the mass ratio is that the simple substance silicon is the methyl methacrylate and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 5 percent), wherein the revolution is 20 revolutions per minute, and the rotation is 300 revolutions per minute; kneading for 2h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 2%), revolving the mixture at 20 revolutions/min and rotating the mixture at 300 revolutions/min; kneading for 2h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 20 revolutions per minute, and rotating at 300 revolutions per minute; kneading for 2h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 3 is different from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, methyl methacrylate, tetraethoxysilane (the mass ratio is that the simple substance silicon is the methyl methacrylate and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 10 percent), wherein the revolution is 10 revolutions per minute, and the rotation is 100 revolutions per minute; kneading for 4h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 5%), revolving the mixture at 10 revolutions per minute and rotating the mixture at 100 revolutions per minute; kneading for 4h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 20 revolutions per minute, and rotating at 100 revolutions per minute; kneading for 4h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 4 is different from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, methyl methacrylate, tetraethoxysilane (the mass ratio is that the simple substance silicon is the methyl methacrylate and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 20 percent), wherein the revolution is 5 revolutions per minute, and the rotation is 10 revolutions per minute; kneading for 8h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 10%), revolving the mixture at 5 revolutions per minute and rotating the mixture at 10 revolutions per minute; kneading for 8h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 5 revolutions per minute, and rotating at 10 revolutions per minute; kneading for 6h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 5 differs from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, methyl methacrylate, tetraethoxysilane (the mass ratio is that the simple substance silicon is the methyl methacrylate and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 40 percent), wherein the revolution is 1 revolution/min, and the rotation is 0 revolution/min; kneading for 20h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 15%), revolving the mixture at 1 r/min and rotating the mixture at 0 r/min; kneading for 20h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving for 2 revolutions/min, and rotating for 10 revolutions/min; kneading for 20h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 6 differs from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, divinylbenzene, tetraethoxysilane (the mass ratio is that the simple substance silicon is the divinylbenzene and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 20 percent), wherein the revolution is 5 revolutions per minute, and the rotation is 10 revolutions per minute; kneading for 8h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 10%), revolving the mixture at 5 revolutions per minute and rotating the mixture at 10 revolutions per minute; kneading for 8h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 5 revolutions per minute, and rotating at 10 revolutions per minute; kneading for 6h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding an initiator cumene hydroperoxide into the product obtained in the step 1 to promote a polymer monomer to generate a polymerization reaction, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 10% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 7 is different from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, divinylbenzene, tetraethoxysilane (the mass ratio is that the simple substance silicon is the divinylbenzene and the tetraethoxysilane is 90:4:1) and NMP, kneading the mixture (the solid content is 20 percent), wherein the revolution is 5 revolutions per minute, and the rotation is 10 revolutions per minute; kneading for 8h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and NMP, kneading the mixture (the solid content is 10%), revolving the mixture at 5 revolutions per minute and rotating the mixture at 10 revolutions per minute; kneading for 8h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 5 revolutions per minute, and rotating at 10 revolutions per minute; kneading for 6h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, polymerization reaction: adding dicumyl peroxide serving as an initiator into the product obtained in the step (1) to promote a polymer monomer to perform polymerization reaction, and coating the generated polymer network structure on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 90% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 mu m;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 8 differs from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing simple substance silicon with the particle size of 100nm, divinylbenzene, tetraethoxysilane (the mass ratio of the simple substance silicon to the divinylbenzene to the tetraethoxysilane is 90:4:1) and acetone, kneading the mixture (the solid content is 20 percent), wherein the revolution is 5 revolutions per minute, and the rotation is 10 revolutions per minute; kneading for 8h to obtain a mixture 1; mixing conductive carbon black, polyvinylpyrrolidone (the mass ratio of the conductive carbon black to the polyvinylpyrrolidone is 4.9:0.1) and acetone, kneading the mixture (the solid content is 10%), revolving the mixture at 5 revolutions/min and rotating the mixture at 10 revolutions/min; kneading for 8h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio of simple substance silicon to conductive carbon black is 90:4.9), kneading continuously, revolving at 5 revolutions per minute, and rotating at 10 revolutions per minute; kneading for 6h to obtain mixed slurry in which the polymer monomer, the nano silicon-based material and the conductive carbon black are uniformly dispersed;
step 2, pelletizing: adjusting the spray drying condition (the drying temperature is 60 ℃, the drying temperature is higher than the boiling point of acetone at the moment and lower than the boiling point of divinylbenzene, so that the solvent is volatilized during the pelletizing process, and the polymer monomer is still distributed on the surfaces of the nano primary particles and the conductive agent components) to prepare the silicon-carbon secondary particles with the particle diameter of 10 mu m;
step 3, polymerization reaction: placing the secondary particles obtained in the step (2) in an initiator dibenzoyl peroxide atmosphere to promote a polymer monomer to perform polymerization reaction, and coating the generated polymer network structure on the surfaces of the nano primary particles and the conductive carbon black;
the rest is the same as that of embodiment 1 and will not be repeated here.
Embodiment 9 differs from embodiment 1 in that this embodiment includes the following steps:
step 1, kneading: mixing 100 nm-sized silica + artificial graphite (silica: artificial graphite in a mass ratio of 1: 9), methyl methacrylate, methyl vinyldimethoxysilane (methyl methacrylate: methylvinyldimethoxysilane: 90:4:1 in a mass ratio of (silica + artificial graphite)), and NMP (solid content: 20%), kneading, revolving at 5 revolutions/min, and rotating at 10 revolutions/min; kneading for 8h to obtain a mixture 1; mixing graphene, polyoxyethylene alkylphenol ether (the mass ratio of graphene to polyoxyethylene alkylphenol ether is 4.9:0.1) and NMP, kneading the mixture (the solid content is 5%), revolving the mixture at 5 revolutions/min and rotating the mixture at 10 revolutions/min; kneading for 8h to obtain a mixture 2; mixing the mixture 1 and the mixture 2 (the mass ratio is (silicon monoxide + artificial graphite): graphene is 90:4.9), kneading continuously, revolving for 5 revolutions/min, and rotating for 10 revolutions/min; kneading for 6h to obtain mixed slurry with uniformly dispersed polymer monomers, nano silicon-based materials and graphene;
step 2, polymerization reaction: adding an initiator tert-butyl peroxybenzoate into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein a generated polymer network structure is coated on the surfaces of the primary nano-particles and the conductive carbon black;
step 3, pelletizing: after 50% of the polymerization reaction occurs, adjusting the spray drying condition to prepare silicon-carbon secondary particles with the particle diameter of 10 microns;
the rest is the same as that of embodiment 1 and will not be repeated here.
Assembling the battery: stirring the silicon-carbon negative electrode material prepared in comparative example, example 1 to example 10 with a conductive agent, a binder and a solvent to obtain electrode slurry, and then coating the electrode slurry on a current collector to form a negative electrode; assembling the negative electrode, the positive electrode (lithium cobaltate is used as an active substance) and the isolating membrane to obtain a bare cell, and then bagging to perform top side sealing, drying, liquid injection, standing, formation, shaping and degassing to obtain a finished battery.
And (3) testing the material performance:
and (3) gram capacity test: the gram capacity test of the battery cores prepared from the silicon-carbon materials of the examples and the comparative examples is carried out in an environment at 25 ℃ according to the following flow: standing for 3 min; charging to 4.2V by a constant current of 0.2C and charging to 0.05C by a constant voltage of 4.2V; standing for 3 min; discharging to 3.0V at constant current of 0.2C to obtain discharge capacity D1; standing for 3 min; discharging to 3.85V at constant current of 0.2C; and (3) standing for 3min, then completing the capacity test, and dividing the weight of the silicon-carbon material in the negative electrode plate by D1 to obtain the gram capacity of the negative electrode, wherein the obtained result is shown in Table 1.
And (3) rate performance test: the rate performance of the battery cells prepared from the silicon-carbon materials of the examples and the comparative examples is tested in an environment at 25 ℃ according to the following procedures: standing for 3 min; charging to 4.2V by a constant current of 0.2C and charging to 0.05C by a constant voltage of 4.2V; standing for 3 min; discharging to 3.0V at constant current of 0.2C to obtain discharge capacity D1; standing for 3 min; charging to 4.2V by a constant current of 0.2C and charging to 0.05C by a constant voltage of 4.2V; standing for 3 min; discharging the 2C to 3.0V at constant current to obtain discharge capacity D21; standing for 3 min; rate performance testing was then completed and the cell rate performance was D2/D1 x 100% with the results shown in table 1.
And (3) cycle test, namely, performing cycle test on the battery cells prepared from the silicon-carbon materials of the examples and the comparative examples in an environment at 25 ℃ according to the following flow: standing for 3 min; charging to 4.2V by a constant current of 0.2C and charging to 0.05C by a constant voltage of 4.2V; standing for 3 min; discharging to 3.0V at constant current of 0.2C to obtain discharge capacity D1; standing for 3min, charging to 4.2V at constant current of 0.2C and charging to 0.05C at constant voltage of 4.2V; standing for 3 min; discharging to 3.0V at constant current of 0.2C to obtain discharge capacity Di; standing for 3min "and repeating 299 times to obtain D300, then completing the cycle test, and calculating the capacity retention rate to be D300/D1 × 100%, and obtaining the results shown in Table 1.
TABLE 1 electrochemical performance of assembled cells made of silicon carbon negative electrode materials prepared in different comparative examples and examples
From table 1, the silicon-carbon negative electrode material with excellent performance can be prepared, and the battery cell assembled by taking the silicon-carbon negative electrode material as the negative electrode active material has excellent electrochemical performance. Specifically, comparing the comparative example with examples 1 to 5, it can be seen that, with the increase of solid content, matching with a proper kneading and stirring process, nano silicon-based secondary particles with excellent performance can be prepared (the obtained battery cell has excellent electrochemical performance). However, too high a solid content will also affect the dispersing effect, thereby degrading the material properties. From examples 4, 6 and 7, it can be seen that too low or too high a progress of the polymerization reaction during granulation affects the electrochemical properties of the final material. This is because when the polymerization degree is excessive, the polymer has fluidity, and when the polymerization degree is too high, the viscosity of the slurry is greatly increased; these conditions will affect the morphology and structure of the granules during granulation, eventually leading to poor material properties. The present invention has general applicability as can be seen from the various embodiments.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (6)
1. The preparation method of the silicon-carbon anode material is characterized in that the silicon-carbon anode material comprises a core structure and a shell structure, wherein the core structure is provided with a secondary particle structure formed by uniformly dispersing nano primary particles in a conductive agent and then tightly stacking the nano primary particles, and the nano primary particles comprise nano silicon-based particles; conductive networks are distributed among the nano silicon-based particles, among the conductive agents and between the nano silicon-based particles and the conductive agents, and the conductive networks are tightly connected with the nano silicon-based particles and the conductive agents;
the preparation method mainly comprises the following steps:
step 1, kneading: mixing and kneading components at least containing nano primary particles and polymer monomers, so that the polymer monomers are uniformly dispersed on the surfaces of the nano primary particles to obtain precursor slurry;
step 2, polymerization reaction: adding an initiator into the product obtained in the step (1) to promote a polymerization reaction of a polymer monomer, wherein the generated polymer network structure is coated on the surface of the primary nano-particles;
step 3, pelletizing: selecting the product obtained in the step (2) which has a certain degree of polymerization reaction, and pelletizing to obtain secondary particles;
step 4, preparing a silicon-carbon negative electrode: coating and carbonizing the product obtained in the step 3 to obtain a finished silicon-carbon cathode material;
step 1 the kneading process is: kneading the nano primary particles, the silane coupling agent, the polymer monomer and the solvent 1 to obtain a mixture 1; kneading the conductive agent, the surfactant and the solvent 2 to obtain a mixture 2; and then blending the mixture 1 and the mixture 2, and uniformly dispersing to obtain precursor slurry.
2. The preparation method of the silicon-carbon anode material as claimed in claim 1, wherein the conductive network is obtained by carbonizing a high polymer material; and before carbonization, the high polymer material is uniformly distributed between the nano silicon-based particles and the conductive agent, and the nano silicon-based particles and the conductive agent are tightly bonded together.
3. The method for preparing the silicon-carbon negative electrode material as claimed in claim 2, wherein the polymer material is obtained by in-situ polymerization of a polymer monomer.
4. The preparation method of the silicon-carbon anode material as claimed in claim 1, wherein the nano silicon-based particles are elemental silicon particles or/and silicon oxide particles; the conductive agent comprises at least one of conductive carbon black, carbon nano tubes, graphene and a conductive network obtained by carbonizing a high polymer material; the primary particles further comprise non-nano silicon-based negative electrode particles; the non-nano silicon-based negative electrode particles are at least one of natural graphite, artificial graphite, mesocarbon microbeads, soft carbon, hard carbon, petroleum coke, carbon fibers, tin-based negative electrode materials, transition metal nitrides, germanium-based alloys, aluminum-based alloys, antimony-based alloys and magnesium-based alloys.
5. The method for preparing the silicon-carbon negative electrode material according to claim 1, wherein the polymer monomer in step 1 comprises methacrylate, styrene, acrylonitrile, methacrylonitrile, divinylbenzene, trimethylolpropane trimethacrylate, N-dimethylacrylamide, N-acryloylmorpholine, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl N-acrylate, cyclohexyl 2-acrylate, dodecyl acrylate, ethylene glycol dimethacrylate, neopentyl glycol diacrylate, 1, 6-hexanediol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol acrylate, bis-trimethylolpropane tetraacrylate, pentaerythritol triacrylate, ethylene glycol diacrylate, propylene glycol, At least one of trimethylolpropane trimethacrylate, propoxylated glycerol triacrylate, tris (2-hydroxyethyl) isocyanuric acid triacrylate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate; the initiator in the step 2 comprises at least one of cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, ditert-butyl peroxide, dibenzoyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.
6. The method for preparing the silicon-carbon anode material as claimed in claim 1, wherein the polymerization reaction in the step 3 is performed to a certain extent that the polymerization reaction is performed by 10% to 90%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710270679.XA CN107069016B (en) | 2017-04-24 | 2017-04-24 | Silicon-carbon negative electrode material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710270679.XA CN107069016B (en) | 2017-04-24 | 2017-04-24 | Silicon-carbon negative electrode material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107069016A CN107069016A (en) | 2017-08-18 |
| CN107069016B true CN107069016B (en) | 2020-08-18 |
Family
ID=59604414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710270679.XA Active CN107069016B (en) | 2017-04-24 | 2017-04-24 | Silicon-carbon negative electrode material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107069016B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109728281B (en) * | 2018-12-31 | 2021-10-12 | 青岛农业大学 | Preparation method of surface modified SiOx electrode material |
| CN109817962A (en) * | 2019-04-02 | 2019-05-28 | 福建蓝海黑石新材料科技有限公司 | A kind of Silicon Based Anode Materials for Lithium-Ion Batteries and preparation method of phenolic resin modification |
| CN111342021B (en) * | 2020-03-12 | 2021-04-02 | 宇恒电池有限公司 | Preparation method of carbon cathode slurry |
| CN111740090B (en) * | 2020-07-06 | 2022-09-16 | 江西理工大学 | Synthetic method for improving conductivity of silicon-based negative electrode material |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104362300A (en) * | 2014-12-02 | 2015-02-18 | 南京工业大学 | Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material |
| CN104362307A (en) * | 2014-09-19 | 2015-02-18 | 南京毕汉特威高分子材料有限公司 | Graphite silicon-based composite anode material and preparation method thereof |
-
2017
- 2017-04-24 CN CN201710270679.XA patent/CN107069016B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104362307A (en) * | 2014-09-19 | 2015-02-18 | 南京毕汉特威高分子材料有限公司 | Graphite silicon-based composite anode material and preparation method thereof |
| CN104362300A (en) * | 2014-12-02 | 2015-02-18 | 南京工业大学 | Preparation method of silicon-carbon composite negative electrode material of lithium ion battery and application of silicon-carbon composite negative electrode material |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107069016A (en) | 2017-08-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107204446B (en) | Lithium ion battery anode material and preparation method thereof | |
| CN107316992B (en) | Lithium titanate negative electrode material and preparation method thereof | |
| CN111048769B (en) | Double-layer coated silicon-based composite anode material and preparation method thereof | |
| US6770397B1 (en) | Binder composition for lithium ion secondary battery electrodes and use thereof | |
| CN107104227B (en) | Lithium ion battery anode material and preparation method thereof | |
| CN107069016B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN106898756B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN103165869B (en) | Modification mesophase spherule negative material, lithium rechargeable battery and preparation method and application | |
| CN107204461B (en) | A kind of anode material for lithium-ion batteries and preparation method thereof | |
| CN107275598B (en) | Lithium titanate negative electrode material and preparation method thereof | |
| CN105390698A (en) | Carbon-silicon composite and manufacturing method thereof | |
| CN107134567A (en) | Silicon-carbon cathode material and preparation method thereof | |
| WO2017031943A1 (en) | Method for preparing negative electrode paste for high-capacity silica-powder-doped lithium battery | |
| CN107086305B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN106848209B (en) | Electrode slurry for lithium secondary battery, electrode, and lithium secondary battery | |
| CN106920949B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN111063872A (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN106941170A (en) | A kind of silicon-carbon cathode material and preparation method thereof | |
| CN107069017B (en) | Preparation method of nano silicon-based secondary particles | |
| CN107069008B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN113690427A (en) | Preparation method of lithium-silicon alloy pole piece, lithium-silicon alloy pole piece and lithium battery | |
| CN107180956B (en) | Lithium titanate negative electrode material and preparation method thereof | |
| CN107069010A (en) | A kind of silicon-carbon cathode material and preparation method thereof | |
| CN107069009B (en) | Silicon-carbon negative electrode material and preparation method thereof | |
| CN106876656B (en) | Preparation method of negative electrode slurry and negative electrode slurry |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |