CN114314593A - Composite micron silicon material and preparation method and application thereof - Google Patents
Composite micron silicon material and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses a composite micron silicon material and a preparation method and application thereof. The composite micron silicon material is of a multilayer core-shell structure and sequentially comprises a micron silicon core, a first coating layer, a cavity layer and a second coating layer from inside to outside; the first coating layer is mainly made of an elastic porous amorphous carbon material and a small amount of graphitized carbon material and is used for relieving the huge volume expansion effect of micron silicon; the second coating layer is a graphitized carbon layer with high mechanical strength and rigidity; meanwhile, a cavity layer is clamped between the two carbon cladding layers, and the three layers cooperate to maintain the structural integrity of the micron silicon particles. In the lithium embedding process of silicon, the first coating layer is firstly compressed in the volume expansion process, most of volume stress is absorbed by the first coating layer, when the first coating layer is compressed to the limit, the continuous volume expansion is relieved by the cavity layer, and the volume stress is absorbed by the second coating layer after the cavity layer is completely consumed, so that the volume expansion of silicon is effectively inhibited, and the performance of the lithium battery is improved.
Description
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a composite micron silicon material and a preparation method and application thereof.
Background
Silicon is a first choice of a next-generation high-capacity lithium ion battery cathode material and has received extensive attention of researchers. However, most of the current inventions use nano-grade silicon, and although nano-silicon can relieve the volume expansion of silicon-based materials to a certain extent, it has the disadvantages of high preparation cost, low tap density, poor consistency and the like, and the development of the nano-silicon is limited.
Compared with nano silicon, the micron silicon has the advantages of low cost, high tap density, less interface side reaction and the like. However, micron silicon also has larger volume expansion, so that the cycle performance of the micron silicon is seriously attenuated, and the micron silicon is difficult to be put into practical use.
Therefore, the development of a lithium battery cathode material which has low expansion rate, stable structure and good cycle performance and is suitable for large-scale production is needed.
Disclosure of Invention
Aiming at the limitations existing in the prior art, the invention provides a composite micron silicon material and a preparation method and application thereof. The composite micron silicon material has a multilayer core-shell structure and sequentially comprises a micron silicon core, a first coating layer, a cavity layer and a second coating layer from inside to outside. The first coating layer is mainly made of an elastic porous amorphous carbon material and a small amount of graphitized carbon material and is used for relieving the huge volume expansion effect of micron silicon; the second coating layer is a graphitized carbon layer with high mechanical strength and rigidity; meanwhile, a cavity layer is clamped between the two carbon coating layers, and the three layers cooperate with each other to maintain the structural integrity of the micron silicon composite particles. In the lithium embedding process of silicon, the first coating layer of the inner layer is firstly compressed in the volume expansion process, most of the volume stress is absorbed by the first coating layer, when the first coating layer is compressed to the limit, the cavity layer assists in relieving when the volume expansion is continued, and when the cavity layer is completely consumed, the second coating layer (rigid graphitized carbon layer) on the outermost layer absorbs the volume stress.
In order to achieve the above object, one of the objects of the present invention is to provide a composite micron silicon material, which is a multilayer core-shell structure, and the multilayer core-shell structure sequentially comprises a micron silicon core, a first coating layer, a cavity layer, and a second coating layer from inside to outside;
the first coating comprises an amorphous carbon layer and a graphitized carbon layer; the graphitized carbon layer is positioned on the upper surface of the amorphous carbon layer;
the second coating layer includes a graphitized carbon layer.
Preferably, the thickness of the first coating layer is 5-200 nm; preferably, the thickness of the first coating layer is 5-40 nm; more preferably, the thickness of the first clad layer is 13 to 40 nm;
the thickness of the cavity layer is 0.1-20 nm; preferably, the thickness of the cavity layer is 1-15 nm; more preferably, the thickness of the cavity layer is 1 to 10 nm;
the thickness of the graphitized carbon layer is 5-20 nm; preferably, the graphitized carbon layer has a thickness of 5 to 15nm, and more preferably, the graphitized carbon layer has a thickness of 5 to 14 nm.
Preferably, in the first coating layer, the ratio of the thicknesses of the amorphous carbon layer and the graphitized carbon layer is 1.5-30: 1; preferably, the ratio of the thicknesses of the amorphous carbon layer and the graphitized carbon layer is 1.5-25: 1; more preferably, the ratio of the thicknesses of the amorphous carbon layer and the graphitized carbon layer is 2 to 19: 1;
in the micron silicon core, the particle size of micron silicon is 1-10 um;
the tap density of the composite micron silicon material is 0.6-1.3g/cm3Preferably, the tap density of the composite micron silicon material is 0.8-1.1g/cm3More preferably, the tap density of the composite micron silicon material is 0.9-1g/cm3。
The second purpose of the invention is to provide a preparation method of the composite micron silicon material, which comprises the following steps:
(1) construction of organic high molecular Polymer: coating an organic high molecular polymer on the surface of the micron silicon by adopting a liquid phase method or a solid phase method, and optionally sintering to obtain a material which is marked as a sample 1;
(2) loading of the first coating layer and the catalyst layer: coating a layer of catalyst on the surface of the sample 1, sintering, and forming a first coating layer and a catalyst layer on the surface of the micron silicon, which is marked as a sample 2;
the catalyst is a catalyst for graphitizing a carbon source;
(3) construction of the graphitized carbon layer: coating the organic high molecular polymer on the surface of the sample 2 again by adopting a liquid phase method or a solid phase method, and sintering to coat a layer of graphitized carbon layer on the surface of the sample 2, and marking as a sample 3;
(4) construction of the cavity layer: and etching the catalyst layer in the sample 3 to obtain the composite micron silicon material.
Preferably, in the step (1), the method for introducing the organic high molecular polymer by using a liquid phase method comprises the following steps: dispersing micron silicon in a solution, then adding a polymerization monomer and optionally a polymerization catalyst, carrying out in-situ polymerization, carrying out suction filtration and drying, and forming an organic high molecular polymer coating layer on the surface of the micron silicon;
in the invention, the reaction conditions for introducing the organic high molecular polymer by the liquid phase method are conventional reaction raw materials and conventional reaction conditions adopted for forming the polymer by the existing in-situ polymerization; more preferably, the concentration of the polymerization monomer in the polymerization system is 0.01 to 1 mol/L; the concentration of the polymerization catalyst is 0.001-0.5 mol/L; the concentration of micron silicon is 5-50 wt%; the polymerization temperature is 10-80 ℃; the polymerization time is 1-20 h;
the method for introducing the organic high molecular polymer by adopting a solid phase method comprises the following steps: mixing micron silicon and an organic high molecular polymer, fusing particles, forming a coating layer of the organic high molecular polymer on the surface of the micron silicon, sintering, and forming a material with a porous carbon layer on the surface of the micron silicon, wherein the material is marked as a sample 1;
in the invention, the reaction conditions for introducing the organic high molecular polymer by the solid phase method are conventional reaction raw materials and conventional reaction conditions adopted by the existing solid phase compounding; more preferably, the mass ratio of the micron silicon to the organic high molecular polymer when blended is 1: 0.05-0.5; the mixing time is 0.5-5h, and the mixing temperature is 20-300 ℃; the sintering temperature is 500-.
Preferably, in the step (2), in the catalyst layer, the active element of the catalyst is at least one of nickel, iron or cobalt;
the coating mode of the catalyst comprises a coating mode of mixing, stirring and evaporating a soluble metal salt solution of an active element in the catalyst with the sample 1; or a coating mode of chemical plating, electroplating, fluidized bed and spray drying; preferably, the sample 1 is put into an aqueous solution containing a catalyst active element to reduce the surface of the sample 1 to obtain a coating mode of chemical plating of a catalyst simple substance through a chemical reaction; or putting the sample 1 into an aqueous solution containing a catalyst element, and generating a coating mode of electroplating of a catalyst simple substance on the surface of the sample 1 by an electrochemical method; or a fluidized bed or spray drying coating mode of loading the solution containing the catalyst elements on the surface of the sample 1 in an atomization mode;
in the invention, the coating mode of the catalyst is selected from the existing conventional reaction conditions, and the concentration of the solution of the active element is more preferably 0.4-0.6 mol/L; the mass ratio of sample 1 to the active elements of the catalyst was 1: 0.05 to 3;
the sintering temperature is 500-;
the thickness of the catalyst layer is 0.1-20 nm.
Preferably, in the step (3), the method for introducing the organic high molecular polymer by using a liquid phase method comprises the following steps: dispersing a sample 2 in a solution, adding a polymerization monomer and optionally a polymerization catalyst, carrying out in-situ polymerization, carrying out suction filtration and drying, and forming an organic high molecular polymer coating layer on the surface of the sample 2;
in the invention, the reaction conditions for introducing the organic high molecular polymer by the liquid phase method are conventional reaction raw materials and conventional reaction conditions adopted for forming the polymer by the existing in-situ polymerization; more preferably, the concentration of the polymerization monomer in the polymerization system is 0.01 to 1 mol/L; the concentration of the polymerization catalyst is 0.001-0.5 mol/L; the concentration of sample 2 was 5-50 wt%; the polymerization temperature is 10-80 ℃; the polymerization time is 1-20 h;
the method for introducing the organic high molecular polymer by adopting a solid phase method comprises the following steps: mixing the sample 2 with an organic high molecular polymer, fusing particles, and forming a coating layer of the organic high molecular polymer on the surface of the sample 2;
in the invention, the reaction condition for introducing the organic high molecular polymer by the solid phase method is the conventional reaction condition of the existing solid phase compounding; more preferably, the mass ratio of sample 2 to the organic high molecular polymer when blended is 1: 0.01-0.5; the mixing time is 0.5-5h, and the mixing temperature is 20-300 ℃;
preferably, the sintering temperature is 500-1000 ℃, the heating rate is 1-10 ℃/min, and the heat preservation time is 0.5-20 hours.
The organic high molecular polymers introduced by adopting a liquid phase method are mutually independent and are selected from at least one of poly-phenolic resin, polydopamine, polypyrrole, polyacrylonitrile, polyvinyl chloride or polyvinylidene chloride;
the organic high molecular polymers introduced by the solid phase method are mutually independent and are selected from at least one of asphalt, phenolic resin, epoxy resin, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, sodium carboxymethylcellulose or polyvinylpyrrolidone.
Preferably, in step (4), sample 3 is placed in a hydrochloric acid solution or contains FeCl3And stirring in a hydrochloric acid solution, performing suction filtration, and repeatedly washing to obtain the composite micron silicon material. Wherein FeCl3The concentration of (A) is 0.01-1mol/L, and the concentration of hydrochloric acid is 0.05-10 mol/L.
The invention also provides an application of the composite micron silicon material as a negative electrode material of a lithium battery.
The fourth purpose of the invention is to provide the application of the negative electrode material of the lithium battery in the lithium battery.
Compared with the prior art, the invention has at least the following advantages:
the invention uses micron silicon as a development precursor, can solve the problems of high cost, low tap density, more surface side reactions and the like of nano silicon, and greatly reduces the material cost.
Aiming at the problem that the volume expansion of a silicon material is large when the silicon material is used as a negative electrode material, a multilayer core-shell structure is designed, wherein a first coating layer mainly comprises an elastic porous amorphous carbon material and a small amount of graphitized carbon material and is used for relieving the huge volume expansion effect of micron silicon; the second coating layer is a graphitized carbon layer with high mechanical strength and rigidity, a cavity is formed between the two carbon coating layers, and the three layers cooperate with each other to maintain the structural integrity of the composite particles. The structural design can effectively inhibit the volume expansion of silicon and solve the problems of particle pulverization and the like caused by the expansion of micron silicon.
The carbon layer is graphitized by a catalytic method, and a simple substance containing nickel or iron or cobalt is adopted; or oxides of the elements, soluble salts or infusible salts formed by liquid phase precipitation and the like can be used for carrying out catalytic graphitization on carbon, the graphitized carbon layer is in-situ catalytic coating, the structure is more stable, the bonding force with the surface is stronger, and compared with a graphene sheet layer formed by the existing physical adsorption method, the core-shell graphitized carbon layer can relieve volume expansion and maintain particle integrity.
The preparation method adopted by the invention is simple, can be used for mass preparation, and is suitable for large-scale production.
Drawings
FIG. 1 is a schematic structural diagram of a composite micron silicon material of the present invention;
fig. 2 is a raman spectrum of the first clad layer and the second clad layer in example 1 of the present invention.
Description of reference numerals:
1-micron silicon core, 2-first coating layer, 21-amorphous carbon layer, 22-graphitized carbon layer, 3-cavity layer and 4-second coating layer.
Detailed Description
While the present invention will be described in detail and with reference to the specific embodiments thereof, it should be understood that the following detailed description is only for illustrative purposes and is not intended to limit the scope of the present invention, as those skilled in the art will appreciate numerous insubstantial modifications and variations therefrom.
Example 1
(1) CTAB (cetyl trimethyl ammonium bromide) is stirred and dispersed into water until the CTAB is dissolved, and the solution is clear and transparent, so as to obtain a CTAB solution of 0.0004mol/L,
(2) 200g of micron silicon is added into 500mL of CTAB solution to be stirred and dispersed,
(3) 20g of resorcinol was added to the above solution and stirred until the resorcinol was completely dissolved,
(4) a37% formaldehyde solution was added to the above solution and stirred to preliminarily polymerize formaldehyde and resorcinol (formaldehyde/resorcinol molar ratio of 1: 1).
(5) And adding 2mL of ammonia water into the solution, stirring, catalyzing the polymerization reaction of formaldehyde and resorcinol, stirring for 10 hours at normal temperature under the reaction condition, performing suction filtration, and drying in an oven to obtain the micron silicon material with the phenolic resin coating layer, and marking as a sample 1.
(6) 10g of cobalt nitrate hexahydrate is added into water and stirred until the cobalt nitrate hexahydrate is completely dissolved, wherein the concentration of a cobalt element is 0.5 mol/L.
(7) And (3) dispersing the micrometer silicon material with the phenolic resin coating layer obtained in the step (5) (the mass ratio of the sample 1 to the cobalt element in the cobalt nitrate hexahydrate is 1:0.3) into the solution, heating, evaporating and stirring until the solution is slightly dried, and then putting the solution into an oven for continuous drying.
(8) Putting the materials into a crucible and placing the crucible into a tube furnace, heating the crucible to 800 ℃ at the heating rate of 3 ℃/min under the nitrogen atmosphere, preserving the heat for 2 hours, naturally cooling the crucible to room temperature, and forming a first coating layer and a catalyst layer on the surface of the micron silicon, wherein the sample is marked as sample 2. In the case of sample 2 of the present invention, the polymer coating layer (phenolic resin coating layer) forms an amorphous carbon layer when sintered, but the upper end of the amorphous carbon layer is graphitized at the portion contacting the catalyst, so that the first coating layer of sample 2 includes the amorphous carbon layer and a small amount of graphitized carbon layer.
(9) 2L of water was taken to prepare a Tris buffer solution having a pH of 8 to 13.
(10) And (3) adding 200g of the silicon-carbon material (sample 2) obtained in the step (8) into a Tris solution, and stirring and dispersing.
(11) 20g of dopamine hydrochloride was added to the above solution, and self-polymerization was carried out by stirring.
(12) And (4) performing suction filtration, and drying in an oven to obtain the micron silicon-carbon material with the dopamine coating layer.
(13) The materials are put into a crucible and placed into a tubular furnace, the temperature is raised to 1000 ℃ at the heating rate of 3 ℃/min under the nitrogen atmosphere, the temperature is kept for 2 hours, and then the materials are naturally cooled to room temperature, so that the micron silicon carbon material with double-layer coating layers and catalyzed second coating layer is obtained, namely, the surface of the sample 2 is coated with a graphitized carbon layer, and the sample 3 is marked as the sample 2.
(14) And (3) placing the sample 3 in a hydrochloric acid solution, stirring for 2h, then carrying out suction filtration, and repeatedly washing with deionized water and ethanol for 3 times to obtain the composite micron silicon material, wherein the concentration of hydrochloric acid is 0.5 mol/L.
The composite micron silicon material prepared by the invention is a multilayer core-shell structure, the multilayer core-shell structure comprises a micron silicon core 1, a first coating layer 2, a cavity layer 3 and a second coating layer 4 from inside to outside in sequence, the first coating layer 2 comprises an amorphous carbon layer 21 and a graphitized carbon layer 22, and the specific structure is shown in figure 1.
In the composite micron silicon material prepared by the method, the thickness of the first coating layer is 13nm, the porosity is 40%, wherein the thickness of the amorphous carbon layer is 9nm, and the thickness of the graphitized carbon layer is 4 nm; the thickness of the cavity layer is 10 nm; the thickness of the graphitized carbon layer in the second coating layer is 10 nm; in the micron silicon core, the particle size of the micron silicon is 5 um; the tap density of the composite micron silicon material is 1.0g/cm3. The raman spectrum for verifying the structure of the first cladding layer and the second cladding layer is shown in fig. 2.
Example 2
(1) Adding one part of micron silicon into non-water-soluble asphalt (the mass ratio of the micron silicon to the asphalt is 1: 0.2), blending for 2 hours at 40 ℃, and then putting into a particle fusion machine for particle fusion to obtain the asphalt-coated micron silicon material.
(2) And putting the materials into a crucible, placing the crucible into a tubular furnace, heating to 500 ℃ at a heating rate of 3 ℃/min in a nitrogen atmosphere, and preserving heat for 2h to obtain the carbon-coated micron silicon material, and recording as a sample 1.
(3) Dissolving nickel sulfate hexahydrate in water to obtain a nickel sulfate solution, wherein the concentration of a nickel element in the nickel sulfate is 0.6 mol/L.
(4) And (3) dispersing the micrometer silicon material obtained in the step (2) (sample 1: mass ratio of nickel element in nickel sulfate hexahydrate is 1: 0.1) into the solution (3).
(5) And adding sodium hydroxide with a stoichiometric ratio which just forms a nickel hydroxide precipitate into the solution to generate a nickel hydroxide precipitate, stirring for 15min, immediately performing suction filtration, and drying in an oven.
(6) And (5) grinding, crushing and sieving the material obtained in the step (5).
(7) Putting the materials into a crucible and placing the crucible into a tube furnace, heating to 500 ℃ at a heating rate of 5 ℃/min under a nitrogen atmosphere, preserving heat for 10min, then heating to 800 ℃ at a heating rate of 3 ℃/min, preserving heat for 4h, naturally cooling to room temperature, and forming a first coating layer and a catalyst layer on the surface of the micron silicon, wherein the first coating layer and the catalyst layer are marked as sample 2.
(8) 2L of water was taken to prepare a Tris buffer solution having a pH of 8 to 13.
(9) And (4) taking 200g of the silicon-carbon material obtained in the step (7), adding into a Tris solution, and stirring and dispersing for 2 h.
(10) And adding 5g of dopamine hydrochloride into the solution, stirring to enable the dopamine hydrochloride to be polymerized automatically, filtering, and drying in a drying oven to obtain the micron silicon-carbon material with the dopamine coating layer.
(11) The materials are put into a crucible and placed into a tubular furnace, the temperature is raised to 800 ℃ at the heating rate of 3 ℃/min under the nitrogen atmosphere, the temperature is kept for 2 hours, and then the materials are naturally cooled to room temperature, so that the composite micron silicon-carbon material which is provided with double-layer coating layers and has the second coating layer being completely catalyzed is obtained and is marked as a sample 3.
(12) Sample 3 was placed in a FeCl-containing chamber3Stirring in hydrochloric acid solution for 2h, filtering, washing with deionized water and ethanol repeatedly for 3 times to obtain composite micrometer silicon material, wherein FeCl3The concentration of (A) is 0.05mol/L, and the concentration of hydrochloric acid is 0.2 mol/L.
The composite micron silicon material prepared by the invention is a multilayer core-shell structure, the multilayer core-shell structure comprises a micron silicon core 1, a first coating layer 2, a cavity layer 3 and a second coating layer 4 from inside to outside in sequence, the first coating layer 2 comprises an amorphous carbon layer 21 and a graphitized carbon layer 22, and the specific structure is shown in figure 1.
In the composite micron silicon material prepared by the method, the thickness of the first coating layer is 20nm, the porosity is 40%, wherein the thickness of the amorphous carbon layer is 19nm, and the thickness of the graphitized carbon layer is 1 nm; the thickness of the cavity layer is 0.5 nm; the thickness of the graphitized carbon layer in the second coating layer is 5 nm; in the micron silicon core, the particle size of the micron silicon is 3 um; the tap density of the composite micron silicon material is 0.95g/cm3。
Example 3
(1) 200g of microsilica were dispersed in 1L of deionized water containing 50g of pyrrole monomers.
(2) And adding 4g of ammonium persulfate into the solution, stirring at 25 ℃ for 5h, performing suction filtration and drying to obtain the polypyrrole-coated micron silicon material, and marking as a sample 1.
(3) 7g of ferric chloride was dissolved in 100g of deionized water to obtain a ferric chloride solution.
(4) And (3) adding the micron silicon material obtained in the step (2) into a reaction cavity of a fluidized bed, and starting equipment to heat at 150 ℃.
(5) Atomizing and spraying the solution obtained in the step (3) into a cavity of a fluidized bed at the speed of 1g/min through a peristaltic pump to obtain the material with the surface containing the iron element coating.
(6) And (3) putting the material obtained in the step (5) into a crucible, placing the crucible into a tube furnace, heating to 700 ℃ at a heating rate of 2 ℃/min under a nitrogen atmosphere, preserving heat for 4h, naturally cooling to room temperature, and forming a first coating layer and a catalyst layer on the surface of the micrometer silicon, wherein the sample is marked as sample 2.
(7) 200g of sample 2 and 50g of epoxy resin are mixed and then put into a mechanical fusion machine for mixing to obtain a sample coated with the epoxy resin.
(8) The materials are put into a crucible and placed in a tubular furnace, the temperature is raised to 500 ℃ at the heating rate of 5 ℃/min for 2h under the nitrogen atmosphere, the temperature is raised to 1000 ℃ at the heating rate of 1 ℃/min, the temperature is maintained for 2h, and then the materials are naturally cooled to room temperature, so that the surface of the sample 2 is coated with a graphitized carbon layer, and the graphitized carbon layer is marked as a sample 3.
(9) And (3) placing the sample 3 in a hydrochloric acid solution, stirring for 2 hours, then carrying out suction filtration, and repeatedly washing with deionized water and ethanol for 3 times to obtain the composite micron silicon material, wherein the concentration of hydrochloric acid is 1 mol/L.
The composite micron silicon material prepared by the invention is a multilayer core-shell structure, the multilayer core-shell structure comprises a micron silicon core 1, a first coating layer 2, a cavity layer 3 and a second coating layer 4 from inside to outside in sequence, the first coating layer 2 comprises an amorphous carbon layer 21 and a graphitized carbon layer 22, and the specific structure is shown in figure 1.
In the composite micron silicon material prepared by the method, the thickness of the first coating layer is 30nm, the porosity is 50%, wherein the thickness of the amorphous carbon layer is 24nm, and the thickness of the graphitized carbon layer is 6 nm; the thickness of the cavity layer is 4 nm; the thickness of the graphitized carbon layer in the second coating layer is 14 nm; in the micron silicon core, the particle size of the micron silicon is 6 um; the tap density of the composite micron silicon material is 0.92g/cm3。
Example 4
(1) And (3) uniformly mixing 200g of micron silicon and 60g of polyacrylonitrile, and mechanically fusing to obtain the micron silicon material with the surface coated with the polyacrylonitrile, wherein the micron silicon material is marked as a sample 1.
(2) 8g of nickel nitrate hexahydrate was dissolved in 100g of deionized water to obtain a nickel nitrate solution.
(3) And (3) mixing the nickel nitrate solution obtained in the step (2) with the sample 1, then adding the mixture into a solution containing sodium hypophosphite and sodium acetate, stirring for reaction for 0.5h, and then carrying out suction filtration and drying. Wherein the concentration of the sodium hypophosphite is 0.2mol/L, and the concentration of the sodium acetate is 0.2 mol/L.
(4) And (4) putting the material obtained in the step (3) into a crucible, placing the crucible into a tube furnace, heating to 750 ℃ at a heating rate of 2 ℃/min in a nitrogen atmosphere, preserving heat for 4h, naturally cooling to room temperature, and forming a first coating layer and a catalyst layer on the surface of the micrometer silicon, wherein the sample is marked as sample 2.
(5) 200g of sample 2 and 60g of polyvinyl chloride are mixed and then put into a mechanical fusion machine for mixing to obtain a sample coated with polyvinyl chloride on the surface.
(6) The materials are put into a crucible and placed in a tubular furnace, the temperature is raised to 600 ℃ at the heating rate of 5 ℃/min for 2h under the nitrogen atmosphere, the temperature is raised to 1000 ℃ at the heating rate of 1 ℃/min, the temperature is maintained for 2h, and then the materials are naturally cooled to room temperature, so that the surface of the sample 2 is coated with a graphitized carbon layer, and the graphitized carbon layer is marked as a sample 3.
(7) Sample 3 was placed in a FeCl-containing chamber3Stirring in hydrochloric acid solution for 1h, filtering, washing with deionized water and ethanol repeatedly for 3 times to obtain composite micrometer silicon material, wherein FeCl3The concentration of (2) is 0.8mol/L, and the concentration of hydrochloric acid is 5 mol/L.
The composite micron silicon material prepared by the invention is a multilayer core-shell structure, the multilayer core-shell structure comprises a micron silicon core 1, a first coating layer 2, a cavity layer 3 and a second coating layer 4 from inside to outside in sequence, the first coating layer 2 comprises an amorphous carbon layer 21 and a graphitized carbon layer 22, and the specific structure is shown in figure 1.
In the composite micron silicon material prepared by the method, the thickness of the amorphous carbon layer is 30nm, and the thickness of the graphitized carbon layer is 10 nm; the thickness of the cavity layer is 6 nm; the thickness of the graphitized carbon layer in the second coating layer is 8 nm; in the micron silicon core, the particle size of the micron silicon is 7 um; the tap density of the composite micron silicon material is 0.9g/cm3。
Comparative example 1
The same pure micron silicon as in example 1 was used as the material for the negative electrode of lithium batteries.
Comparative example 2
The composite micron silicon material prepared in the above examples and comparative examples is mixed with CNT and CMC + SBR according to a mass ratio of 90: 5: 5 respectively manufacturing pole pieces and using the pole pieces as working electrodes, and using LiPF6The method comprises the following steps of (1: 1:1) assembling a button cell by taking/DMC + EC + DEC (1: 1:1) as an electrolyte and a metal lithium sheet as a negative electrode, charging and discharging until the voltage is 0.01-0.8V, and measuring the first charging specific capacity, the first coulombic efficiency and the 50-week cycle retention rate, wherein the results are shown in Table 1.
TABLE 1
From table 1, it can be seen that when the composite micrometer silicon material prepared in the embodiment of the present invention is used as a negative electrode of a lithium battery, the expansion rate of a first lithium-embedded pole piece is significantly reduced, and the cycle retention rate is significantly improved after 50 cycles, which indicates that the composite micrometer silicon material prepared in the present invention can effectively inhibit the volume expansion of silicon, and improve the cycle performance of the lithium battery.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (10)
1. A composite micron silicon material is characterized in that:
the composite micron silicon material is of a multilayer core-shell structure, and the multilayer core-shell structure sequentially comprises a micron silicon core, a first coating layer, a cavity layer and a second coating layer from inside to outside;
the first coating comprises an amorphous carbon layer and a graphitized carbon layer; the graphitized carbon layer is positioned on the upper surface of the amorphous carbon layer;
the second coating layer includes a graphitized carbon layer.
2. The composite micron silicon material of claim 1, wherein:
the thickness of the first coating layer is 5-200 nm;
the thickness of the cavity layer is 0.1-20 nm;
the thickness of the graphitized carbon layer is 5-20 nm.
3. The composite micron silicon material of claim 1, wherein:
in the first coating layer, the thickness ratio of the amorphous carbon layer to the graphitized carbon layer is 1.5-30: 1;
in the micron silicon core, the particle size of micron silicon is 1-10 um;
the tap density of the composite micron silicon material is 0.6-1.3g/cm3。
4. The method for preparing a composite micron silicon material according to any one of claims 1 to 3, wherein the method for preparing comprises the following steps:
(1) construction of organic high molecular Polymer: coating an organic high molecular polymer on the surface of the micron silicon by adopting a liquid phase method or a solid phase method, and optionally sintering to obtain a material which is marked as a sample 1;
(2) loading of the first coating layer and the catalyst layer: coating a layer of catalyst on the surface of the sample 1, sintering, and forming a first coating layer and a catalyst layer on the surface of the micron silicon, which is marked as a sample 2;
the catalyst is a catalyst for graphitizing a carbon source;
(3) construction of the graphitized carbon layer: coating the organic high molecular polymer on the surface of the sample 2 again by adopting a liquid phase method or a solid phase method, and sintering to coat a layer of graphitized carbon layer on the surface of the sample 2, and marking as a sample 3;
(4) construction of the cavity layer: and etching the catalyst layer in the sample 3 to obtain the composite micron silicon material.
5. The method for preparing a composite micron silicon material as claimed in claim 4, wherein:
in the step (1), the step (c),
the method for introducing the organic high molecular polymer by adopting the liquid phase method comprises the following steps: dispersing micrometer silicon in a solution, then adding a polymerization monomer and an optional polymerization catalyst, carrying out in-situ polymerization, carrying out suction filtration and drying, and forming an organic high polymer coating layer on the surface of the micrometer silicon, wherein the coating layer is marked as a sample 1;
the method for introducing the organic high molecular polymer by adopting a solid phase method comprises the following steps: mixing micron silicon with an organic high molecular polymer, fusing particles, forming a coating layer of the organic high molecular polymer on the surface of the micron silicon, sintering, and forming a material with a porous carbon layer on the surface of the micron silicon, wherein the material is marked as a sample 1.
6. The method for preparing a composite micron silicon material as claimed in claim 4, wherein:
in the step (2),
in the catalyst layer, the active element of the catalyst is at least one of nickel, iron or cobalt;
the coating mode of the catalyst comprises a coating mode of mixing, stirring and evaporating a soluble metal salt solution of an active element in the catalyst with the sample 1; or a coating mode of chemical plating, electroplating, fluidized bed and spray drying;
sintering at 500-1000 deg.c, heating rate of 1-10 deg.c/min and maintaining for 0.5-20 hr;
the thickness of the catalyst layer is 0.1-20 nm.
7. The method for preparing a composite micron silicon material as claimed in claim 4, wherein:
in the step (3), the method for introducing the organic high molecular polymer by adopting a liquid phase method comprises the following steps: dispersing a sample 2 in a solution, adding a polymerization monomer and optionally a polymerization catalyst, carrying out in-situ polymerization, carrying out suction filtration and drying, and forming an organic high molecular polymer coating layer on the surface of the sample 2;
the method for introducing the organic high molecular polymer by adopting a solid phase method comprises the following steps: mixing the sample 2 with an organic high molecular polymer, fusing particles, and forming a coating layer of the organic high molecular polymer on the surface of the sample 2;
the sintering temperature is 500-1000 ℃, the temperature rising rate is preferably 1-10 ℃/min, and the heat preservation time is 0.5-20 hours.
8. The method for preparing a composite micron silicon material as claimed in claim 4, wherein:
in the step (1) or the step (3),
the organic high molecular polymers introduced by adopting a liquid phase method are mutually independent and are selected from at least one of poly-phenolic resin, polydopamine, polypyrrole, polyacrylonitrile, polyvinyl chloride or polyvinylidene chloride;
the organic high molecular polymers introduced by the solid phase method are mutually independent and are selected from at least one of asphalt, phenolic resin, epoxy resin, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, sodium carboxymethylcellulose or polyvinylpyrrolidone.
9. The method for preparing a composite micron silicon material as claimed in claim 4, wherein:
in the step (4), the sample 3 is placed in a hydrochloric acid solution or contains FeCl3And stirring in a hydrochloric acid solution, performing suction filtration, and repeatedly washing to obtain the composite micron silicon material.
10. Use of the composite micron silicon material according to any one of claims 1 to 3 as a negative electrode material for lithium batteries.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105870410A (en) * | 2016-04-13 | 2016-08-17 | 中南大学 | Silicon/carbon/cavity/carbon composite material for lithium-ion battery and preparation method and application of silicon/carbon/cavity/carbon composite material |
| CN109713265A (en) * | 2018-12-21 | 2019-05-03 | 桑德集团有限公司 | A kind of silicon-carbon cathode material and preparation method thereof |
| CN113659122A (en) * | 2021-08-16 | 2021-11-16 | 四川金汇能新材料股份有限公司 | Silicon-carbon negative electrode material, preparation method and application |
| CN113707858A (en) * | 2021-08-23 | 2021-11-26 | 上海颂柏智能技术开发中心 | Porous carbon-silicon composite negative electrode material and preparation method thereof |
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| CN105870410A (en) * | 2016-04-13 | 2016-08-17 | 中南大学 | Silicon/carbon/cavity/carbon composite material for lithium-ion battery and preparation method and application of silicon/carbon/cavity/carbon composite material |
| CN109713265A (en) * | 2018-12-21 | 2019-05-03 | 桑德集团有限公司 | A kind of silicon-carbon cathode material and preparation method thereof |
| CN113659122A (en) * | 2021-08-16 | 2021-11-16 | 四川金汇能新材料股份有限公司 | Silicon-carbon negative electrode material, preparation method and application |
| CN113707858A (en) * | 2021-08-23 | 2021-11-26 | 上海颂柏智能技术开发中心 | Porous carbon-silicon composite negative electrode material and preparation method thereof |
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