CN112002885B - Silicon-carbon composite material, preparation method thereof and lithium ion battery - Google Patents

Silicon-carbon composite material, preparation method thereof and lithium ion battery Download PDF

Info

Publication number
CN112002885B
CN112002885B CN202010946269.4A CN202010946269A CN112002885B CN 112002885 B CN112002885 B CN 112002885B CN 202010946269 A CN202010946269 A CN 202010946269A CN 112002885 B CN112002885 B CN 112002885B
Authority
CN
China
Prior art keywords
silicon
carbon
carbon composite
composite material
ozone
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
Application number
CN202010946269.4A
Other languages
Chinese (zh)
Other versions
CN112002885A (en
Inventor
张辉
柏晓
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Academy of Space Technology CAST
Original Assignee
China Academy of Space Technology CAST
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by China Academy of Space Technology CAST filed Critical China Academy of Space Technology CAST
Priority to CN202010946269.4A priority Critical patent/CN112002885B/en
Publication of CN112002885A publication Critical patent/CN112002885A/en
Application granted granted Critical
Publication of CN112002885B publication Critical patent/CN112002885B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

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
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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 provides a silicon-carbon composite material, a preparation method thereof and a lithium ion battery, which comprises the following steps: and mixing the silicon material modified by ultraviolet-ozone or oxidant with the carbon material modified by ultraviolet-ozone to obtain the silicon-carbon composite material. And the carbon material and the silicon material are in close and effective contact, and the two materials are uniformly and alternately distributed. The silicon-carbon composite material has the advantages that the two materials are mutually staggered and have a uniform interweaving structure, and the material has the advantages of high specific capacity and high electrochemical activity of a silicon material, high strength and excellent conductivity of a carbon material. The damage effect of internal stress of the electrode caused by large volume change of silicon in the battery cycle process can be effectively relieved, so that the cycle life of the lithium ion battery electrode is prolonged.

Description

Silicon-carbon composite material, preparation method thereof and lithium ion battery
Technical Field
The invention relates to the technical field of energy storage and conversion, in particular to a silicon-carbon composite material, a preparation method thereof and a lithium ion battery.
Background
At present, a composite material obtained by compounding a silicon material with high theoretical capacity and a conductive carbon material becomes a preferred material of a high-energy-density lithium ion battery electrode. However, the preparation process of the silicon-carbon composite material is complex and the cost is high, and particularly for the silicon-carbon composite material with higher silicon content (more than or equal to 20%), the problem of cracking of the lithium ion battery electrode caused by overlarge volume change (300% -400%) of silicon-intercalated lithium is difficult to solve, so that the practical application of the silicon-carbon composite material is hindered. Therefore, the silicon-carbon composite electrode material has the technical problems of environmental unfriendliness, high cost, complex process and the like in the preparation technology.
In the prior art, the silicon-carbon composite powder/film can be prepared by a vapor deposition method (CVD), a gas-liquid-solid method (VLS), a template method, a pulsed laser method, radio frequency magnetron sputtering, and the like. These preparation methods are relatively harsh in synthesis conditions, require high-temperature or high-vacuum environments, or use raw materials containing flammable and toxic substances (e.g., SiH)4、C2H2) Etc.; meanwhile, the preparation needs multi-step operation, the process is complex, the yield is low, and the method is not suitable for large-scale industrial production.
Wet chemical synthesis techniques are relatively simple methods for preparing silicon carbon composites. Silicon nano particles are dispersed in a carbon material matrix, and the high conductivity and the good mechanical strength of the carbon material are combined, so that the volume expansion of silicon can be relieved to a certain extent, and the embedding position of lithium ions can be increased. However, the simple wet chemical synthesis technology cannot effectively inhibit the agglomeration of nano silicon particles, is difficult to realize the uniform distribution and effective contact between silicon and carbon components, and cannot avoid the problems of electrode crack damage and capacity attenuation in the conventional cycle process. The main reason is that the nano-silicon is not uniformly distributed in the preparation process, so that the silicon is not sufficiently constrained by the carbon material in the nano-space, and the practical application of the high-performance silicon-carbon composite material in the lithium ion battery is further limited.
At present, in the prior art, a silicon material and a carbon material are modified by adopting a pure chemical oxidant and then are compounded, so that the effect is poor.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The first purpose of the invention is to provide a preparation method of a silicon-carbon composite material, which is used for completely or partially solving the problems existing in the preparation process of the existing silicon-carbon composite material.
The second objective of the present invention is to provide a silicon-carbon composite material prepared by the preparation method of the silicon-carbon composite material, wherein two materials in the silicon-carbon composite material are interlaced with each other, and have a uniform interlaced structure, and the material has both the advantages of high specific capacity and high electrochemical activity of the silicon material, and the advantages of high strength and excellent conductivity of the carbon material.
The third purpose of the invention is to provide a lithium ion battery, wherein the silicon-carbon composite material is used as a main material for preparing a battery electrode, and based on the uniformly interwoven structural characteristics of the silicon-carbon composite material, the destructive effect of internal stress of the electrode caused by large volume change of silicon in the battery cycle process can be effectively relieved, so that the cycle life of the lithium ion battery electrode is prolonged.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
a preparation method of a silicon-carbon composite material comprises the following steps:
and mixing the silicon material modified by ultraviolet-ozone or oxidant with the carbon material modified by ultraviolet-ozone to obtain the silicon-carbon composite material.
Preferably, the mass ratio of the carbon material to the silicon material is 8-2: 2-8, and the more preferable mass ratio is 8-5: 2 to 5.
Preferably, the carbon material comprises one or a combination of several of carbon fiber, carbon nanotube, graphite, graphene, hard carbon material and soft carbon material;
the silicon material comprises one or more of simple substance silicon, silicon dioxide and silicon monoxide; the silicon monoxide is SiOxWherein 0 is<x<2。
Preferably, the shape of the carbon material and/or the silicon material comprises one or a combination of a plurality of granular shapes, nanowires and nanotubes; more preferably, the particles are porous particles; more preferably, the particle size of the particulate silicon material and/or carbon material is 20nm to 10 μm.
Preferably, the mixing comprises in particular stirring and/or grinding.
Preferably, the stirring comprises ultrasonic stirring and/or magnetic stirring.
Preferably, the milling comprises sanding or ball milling;
more preferably, the ball milling is wet milling, and the grinding medium of the wet milling comprises one or more of water, ethanol and acetone;
more preferably, the ball milling speed is 200-1500 rpm, and the ball milling time is 0.5-48 h.
Preferably, the time of the ultraviolet-ozone modification is 10 s-2 h, and more preferably 1 min-30 min.
Preferably, the temperature of the ultraviolet-ozone modification treatment is 25-200 ℃, and more preferably 100-180 ℃.
Preferably, the mass of the carbon material or the silicon material modified by the ultraviolet-ozone at each time is 30mg to 600 mg.
Preferably, the oxidant modification specifically comprises the following steps:
and soaking, cleaning and drying the silicon material in a mixed solution of concentrated sulfuric acid and hydrogen peroxide to obtain the surface modified silicon material.
Preferably, in the mixed solution, the volume ratio of the concentrated sulfuric acid to the hydrogen peroxide is 5: 1-1: 5, the mass concentration of the hydrogen peroxide is 30-35%.
Preferably, the cleaning is performed using ultrapure water.
Preferably, the drying comprises vacuum drying and/or freeze drying, and more preferably, the drying time is 1-48 h.
A silicon-carbon composite material is prepared by the preparation method of the silicon-carbon composite material.
An electrode of the lithium ion battery is mainly prepared from the silicon-carbon composite material.
Compared with the prior art, the invention has the beneficial effects that:
(1) the preparation method provided by the invention enables the surfaces of the carbon material and the silicon material to respectively generate the electrostatic attraction functional groups, so that the carbon material and the silicon material are in tight and effective contact, the two materials are uniformly and alternately distributed, the cost is low, the efficiency is high, the process is simple, and the large-scale industrial production can be realized.
(2) According to the preparation method provided by the invention, wet grinding and mixing are adopted in the mixing process, a diffusion double electric layer is formed on the surface of the material, and an electrokinetic phenomenon is generated, so that the physical contact of carbon and a silicon material is improved, and the aggregation phenomenon of the silicon or the carbon material can be relieved due to the repulsion effect generated by the same material due to the same electric property.
(3) The silicon-carbon composite material provided by the invention has a uniform interweaving structure, and has the advantages of high specific capacity and high electrochemical activity of a silicon material, high strength and excellent conductivity of a carbon material.
(4) According to the lithium ion battery provided by the invention, the silicon-carbon composite material is adopted as a main material for preparing the battery electrode, and based on the uniformly-interwoven structural characteristics of the silicon-carbon composite material, the destructive effect of internal stress of the electrode caused by large volume change of silicon in the battery cycle process can be effectively relieved, so that the cycle life of the lithium ion battery electrode is prolonged.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a scanning electron micrograph of a silicon-carbon composite powder prepared in example 1 of the present invention;
FIG. 2 is a scanning electron micrograph of a silicon-carbon composite powder prepared in example 2 of the present invention;
FIG. 3 is a scanning electron micrograph of a silicon-carbon composite powder according to a comparative example of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
According to the preparation method of the silicon-carbon composite material, the silicon material modified by ultraviolet-ozone or oxidant is mixed with the carbon material modified by ultraviolet-ozone to obtain the silicon-carbon composite material. Functional groups with opposite electrical properties are uniformly introduced to the surface of the carbon and/or silicon material, and the problems that the components of the carbon and the silicon material cannot be uniformly distributed and effectively contacted are solved through electrostatic attraction of the carbon and the silicon surface, so that the electrochemical cycle performance of the silicon-carbon composite material is improved.
In some preferred embodiments of the present invention, the mass ratio of the carbon material to the silicon material is 8-2: 2 to 8 (e.g., 8:2, 7:3, 5:5, etc.), and more preferably 8 to 5: 2 to 5.
In some preferred embodiments of the present invention, the type, shape and size of the carbon material is preferred. The carbon material comprises one or more of carbon fiber, carbon nano tube, graphite, graphene, hard carbon material and soft carbon material.
In some preferred embodiments of the present invention, the kind of the silicon material is preferred, and includes one or a combination of elemental silicon, silicon dioxide and silicon monoxide; the silicon monoxide is SiOxWherein 0 is<x<2。
Further, the shapes of the two materials comprise one or a combination of a plurality of materials selected from the group consisting of particles, porous particles, nanowires and nanotubes; the particle size of the particle material is 20 nm-10 μm.
In some preferred embodiments of the present invention, the mixing specifically includes stirring and/or milling in order to achieve adequate mixing of the two materials.
Further, the stirring includes ultrasonic stirring and/or magnetic stirring.
Further, the grinding includes sanding or ball milling.
Further, the ball milling is wet milling, and the grinding medium of the wet milling comprises one or more of water, ethanol and acetone.
Furthermore, wet grinding and mixing are adopted in the mixing process, a diffusion double electric layer is formed on the surface of the material, and an electrokinetic phenomenon is generated, so that the physical contact of carbon and a silicon material is improved, the aggregation phenomenon of the silicon or the carbon material can be relieved due to the repulsion effect generated by the same material due to the same electric property, the ball milling speed is 200-1500 rpm, and the ball milling time is 0.5-48 h.
In some preferred embodiments of the present invention, the time of the uv-ozone modification is 10s to 2h (e.g., 10s, 30s, 1min, 5min, 10min, 20min, 30min, 35min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min), and the preferred time is 1min to 30 min.
In some preferred embodiments of the present invention, the temperature of the uv-ozone modification treatment is 25 to 200 ℃ (e.g., 25 ℃, 30 ℃, 35 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃), and more preferably 100 to 180 ℃;
further, the mass of the carbon material or the silicon material modified by the ultraviolet-ozone at each time is 30mg to 600 mg.
In some preferred embodiments of the present invention, the oxidizing agent modification specifically comprises the following steps:
soaking, cleaning and drying the silicon material in a mixed solution of concentrated sulfuric acid and hydrogen peroxide to obtain a surface-modified silicon material;
further, in the mixed solution, the volume ratio of the concentrated sulfuric acid to the hydrogen peroxide is 5: 1-1: 5, the mass concentration of the hydrogen peroxide is 30-35%, and preferably, the mixed solution is a piranha solution;
further, the cleaning is performed with ultrapure water;
further, the drying comprises vacuum drying and/or freeze drying, and more preferably, the drying time is 1-48 h.
The silicon-carbon composite material is prepared by the preparation method of the silicon-carbon composite material, two materials in the silicon-carbon composite material are mutually staggered and have a uniform interweaving structure, and the material has the advantages of high specific capacity and high electrochemical activity of a silicon material, and also has the advantages of high strength and excellent conductivity of the carbon material.
An electrode of the lithium ion battery is mainly prepared from the silicon-carbon composite material. Based on the uniformly-interwoven structural characteristics of the silicon-carbon composite material, the damage effect of internal stress of the electrode caused by large volume change of silicon in the battery cycle process can be effectively relieved, so that the cycle life of the lithium ion battery electrode is prolonged.
Example 1
The materials used in this example were:
silicon material: nano silicon (Si) particles, (average particle size 50 nm);
carbon material: selecting carbon fibers (CNFs);
the mass ratio of the nano silicon to the carbon fiber is 70.05: 29.95.
the synthesis method of the composite material specifically comprises the following steps:
(1) ultraviolet-ozone combined modified carbon material:
carrying out ultraviolet-ozone treatment at a temperature of 150 ℃ and a wavelength of 253.7nm by using a UVO-Cleaner (ultraviolet ozone cleaning machine), and irradiating 200mg of CNFs for 20 minutes to enable the surfaces of the CNFs to have carboxyl functional groups, wherein the marks are o-CNFs;
(2) surface chemical modification of silicon material:
500mg of Si nanoparticles in piranha solution (3:1, V/V H)2SO4:H2O2Hydrogen peroxide solution with the mass concentration of 75 percent), keeping the solution at 80 ℃, stirring for 1h, then filtering and washing by using ultrapure water, and drying in vacuum for 12h at 50 ℃ to ensure that the Si surface has hydroxyl functional groups and is marked as Si-OH. Dispersing 500mg Si-OH into 100mL absolute ethanol (not less than 99.5%), ultrasonically treating for 0.5h, pouring 0.5mL Aminopropyltriethoxysilane (APTES) into the solution, magnetically stirring at 70 deg.C for 12h, washing in ethanol, and filteringAnd drying in a vacuum drying oven at 50 ℃ for 12h to obtain Si surface amino functional groups marked as Si-NH2；
(3) Ultrasonic mixing to prepare silicon-carbon composite powder: the mass was combined between 175mg of o-CNFs and 75mg of Si-NH2Ultrasonically mixing the silicon carbide powder in 50mL of ultrapure water for 5 hours, and carrying out suction filtration and vacuum drying for 12 hours to obtain silicon-carbon composite powder marked as Si-o-CNFs, wherein the surface microstructure of the silicon-carbon composite powder is shown in figure 1.
Example 2
The materials used in this example were:
silicon material: nano silicon (Si) particles (average particle size 50 nm);
carbon material: selecting carbon fibers (CNFs);
the mass ratio of the nano silicon to the carbon fiber is 1: 1.
For the modification of the carbon material, step (1) is the same as that of example 1;
(2) ultraviolet-ozone combined modified silicon material:
UV-ozone treatment at 150 deg.C and 253.7nm with UVO-Cleaner, irradiating 300mg of Si nanoparticles for 20min to make silicon surface have hydroxyl functional group, labeled as SiOx；
(3) Ball-milling and mixing to prepare silicon-carbon composite powder:
130mg of o-CNFs were mixed with 130mg of SiOxMixing the silicon carbide powder with 1.5mL of absolute ethyl alcohol, wet-milling the mixture for 1h at a ball-milling speed of 500rpm, and vacuum-drying the mixture for 12h at 50 ℃ to obtain silicon-carbon composite powder with a uniform interweaving structure, wherein the silicon-carbon composite powder is marked as Si-o-o-CNFs, and the surface microstructure of the silicon-carbon composite powder is shown in FIG. 2.
Comparative example
The materials used in this example were:
silicon material: nano silicon (Si) particles, (average particle size 50 nm);
carbon material: selecting carbon fibers (CNFs);
the mass ratio of the nano silicon to the carbon fiber is 70.05: 29.95.
the synthesis method of the composite material specifically comprises the following steps:
(1) acidifying the modified carbon material:
the CNFs were mixed in concentrated sulfuric acid/nitric acid (3:1, V/V H)2SO4:H2O2) Performing intermediate treatment for 12h, filtering and cleaning for multiple times by using ultrapure water until the pH value is 7, and then performing vacuum drying for 12h at 50 ℃ to ensure that the surfaces of the CNFs have carboxyl functional groups and are marked as a-CNFs;
(2) surface chemical modification of silicon material:
500mg of Si nanoparticles in piranha solution (3:1, V/V H)2SO4:H2O2Hydrogen peroxide solution with the mass concentration of 75 percent), keeping the solution at 80 ℃, stirring for 1h, then filtering and washing by using ultrapure water, and drying in vacuum for 12h at 50 ℃ to ensure that the Si surface has hydroxyl functional groups and is marked as Si-OH. Dispersing 500mg Si-OH into 100mL absolute ethyl alcohol (more than or equal to 99.5 percent), after 0.5h of ultrasonic treatment, pouring 0.5mL Aminopropyltriethoxysilane (APTES) into the solution, magnetically stirring at 70 ℃ for 12h, then washing in ethanol, filtering, and drying in a vacuum drying oven at 50 ℃ for 12h to obtain Si surface amino functional groups marked as Si-NH2；
(3) Ultrasonic mixing to prepare silicon-carbon composite powder: a mass of 175mg of a-CNFs was mixed with 75mg of Si-NH2Ultrasonically mixing the silicon-carbon composite powder in 50mL of ultrapure water for 5h, carrying out suction filtration and vacuum drying for 12h to obtain silicon-carbon composite powder marked as Si-a-CNFs, wherein the surface microstructure of the silicon-carbon composite powder is shown in figure 3.
Experimental example 1
By observing the micro-morphology of the silicon-carbon composite powder prepared in the embodiments 1 (fig. 1) and 2 (fig. 2) and the comparative example (fig. 3) through a scanning electron microscope, it can be seen that in the embodiments 1 and 2, the CNFs are interlaced to form a large number of pores, and the Si nanoparticles are uniformly dispersed on the CNFs, which indicates that the silicon material and the carbon material form a uniform interlaced structure in the silicon-carbon composite powder. The comparative example still had a phenomenon of significant nano-agglomeration.
Experimental example 2
The silicon-carbon composite powder material prepared in example 1 was used as a battery electrode active material, mixed with a conductive agent super P and a binder carboxymethyl cellulose (CMC) in a mass ratio of 8:1:1, and placed in a buffer solution (0.17M citric acid +0.07M potassium hydroxide) having a pH of 3 and magnetically stirred for 12 hours, thereby preparing slurry 1.
The silicon-carbon composite powder materials prepared in example 2 and comparative example were prepared into slurry 2 and slurry 3 in the same ratio and method.
And (3) respectively coating the slurry 1, the slurry 2 and the slurry 3 on copper foil, naturally airing for 8 hours, and drying in a vacuum drying oven at 50 ℃ for more than 8 hours to respectively prepare the silicon-carbon composite electrodes for later use.
And (3) carrying out charge-discharge cycle test on the silicon-carbon composite electrode by adopting a half-cell test method, and investigating the cycle reversibility, discharge capacity and the like of the silicon-carbon composite powder. The half cell mainly comprises a metal lithium sheet as a negative electrode, PP/PE/PP as a diaphragm and a prepared silicon-carbon composite electrode as a positive electrode, wherein the electrolyte is 1M LiPF6+ EC: DMC: EMC 1: 1:1 (volume ratio) with the addition of 10% FEC, the half-cells were assembled in a glove box under an inert atmosphere. The voltage range of the charge and discharge test is set to be 0.01-1.5V, the constant charge and discharge current density is 500mA/g, the test temperature is room temperature, and the test results are respectively shown in tables 1, 2 and 3.
Table 1 results of cycle performance test of silicon carbon composite assembled battery prepared in example 1
Number of cycles Specific discharge capacity mAh/g
1 2218
2 1747
100 1343
200 1225
300 1160
400 1063
Table 2 results of cycle performance test of silicon carbon composite assembled battery prepared in example 2
Number of cycles Specific discharge capacity mAh/g
1 1606
2 1144
50 834
100 793
200 657
Table 3 results of cycle performance test of battery assembled by silicon carbon composite material prepared in comparative example
Number of cycles Specific discharge capacity mAh/g
1 2130
2 1660
100 1086
200 880
300 743
400 626
Test results show that the initial specific discharge capacity of the half-cell assembled by the composite materials prepared in the embodiment 1 and the embodiment 2 can reach 2218mAh/g and 1606mAh/g, and the specific discharge capacity of the 2 nd circle is 1747mAh/g and 1144mAh/g respectively. Compared with the 2 nd circle, the capacity retention rate of 100 cycles can respectively reach 76.9 percent and 69.3 percent. The silicon-carbon composite material has higher discharge capacity and cycle stability. The capacity retention rate after 200 times of circulation is 70.1% and 57.4%, wherein the discharge capacity of the half-cell assembled by the composite material of the embodiment 1 can still maintain 1063mAh/g after 400 times of circulation, and the problems of low reversible capacity, poor circulation stability and the like of the existing silicon-carbon material can be effectively solved.
The initial capacity of the half battery assembled by the composite material prepared by the comparative example is 2130mAh/g, and the specific discharge capacity of the 2 nd circle reaches 1660 mAh/g. Compared with the 2 nd circle, the capacity retention rate of 100 circles is only 65.4%, the capacity retention rate of 200 circles is reduced to 53.0%, and the capacity is reduced to 626mAh/g after 400 circles, which is probably because the content of the acidified CNF impurities is high, so that the CNF is not beneficial to electrostatic attraction with the silicon material, and the CNF treated by ultraviolet-ozone is easy to form a uniform interweaving structure with the silicon material, so that the electrochemical cycle stability of the silicon-carbon composite material is beneficial.
While particular embodiments of the present invention have been illustrated and described, it will be appreciated that the above embodiments are merely illustrative of the technical solution of the present invention and are not restrictive; those of ordinary skill in the art will understand that: modifications may be made to the above-described embodiments, or equivalents may be substituted for some or all of the features thereof without departing from the spirit and scope of the present invention; the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention; it is therefore intended to cover in the appended claims all such alternatives and modifications that are within the scope of the invention.

Claims (12)

1. The preparation method of the silicon-carbon composite material is characterized by comprising the following steps:
(1) carrying out ultraviolet-ozone modification on the carbon material to obtain the carbon material with carboxyl functional groups on the surface;
(2) modifying a silicon material by using an oxidant to obtain the silicon material with a hydroxyl functional group on the surface; then mixing the silicon material with the surface provided with the hydroxyl functional group with aminopropyltriethoxysilane to obtain the silicon material with the surface provided with the amino functional group;
(3) mixing the carbon material with the carboxyl functional group on the surface with the silicon material with the amino functional group on the surface to obtain the silicon-carbon composite material;
the time for carrying out ultraviolet-ozone modification on the carbon material is 1-30 min;
the temperature of ultraviolet-ozone modification treatment of the carbon material is 25-200 ℃;
the oxidant modification specifically comprises the following steps:
soaking, cleaning and drying the silicon material in a mixed solution of concentrated sulfuric acid and hydrogen peroxide to obtain the silicon material with the surface provided with hydroxyl functional groups;
in the mixed solution, the volume ratio of the concentrated sulfuric acid to the hydrogen peroxide is 5: 1-1: 5;
the mass ratio of the carbon material to the silicon material is 8-2: 2-8;
the mixing is grinding, the grinding is ball milling, and the ball milling is wet grinding.
2. The preparation method of the silicon-carbon composite material according to claim 1, wherein the mass ratio of the carbon material to the silicon material is 8-5: 2 to 5.
3. The method for preparing the silicon-carbon composite material according to claim 1, wherein the carbon material comprises one or a combination of carbon fibers, carbon nanotubes, graphite, graphene, a hard carbon material and a soft carbon material;
the silicon material comprises one or more of simple substance silicon, silicon dioxide and silicon monoxide;
the silicon oxide is SiOx, wherein 0< x < 2.
4. The method for preparing the silicon-carbon composite material according to claim 1, wherein the shape of the carbon material and/or the silicon material comprises one or more of granular shape, nanowire shape and nanotube shape.
5. The method of producing a silicon-carbon composite material according to claim 4, wherein the particles are porous particles.
6. The method according to claim 4, wherein the particle size of the granular silicon material and/or the particle size of the granular carbon material are 20nm to 10 μm.
7. The method of claim 1, wherein the wet-milled grinding media comprises one or a combination of water, ethanol, and acetone.
8. The preparation method of the silicon-carbon composite material according to claim 1, wherein the ball milling speed is 200-1500 rpm, and the ball milling time is 0.5-48 h.
9. The method for preparing the silicon-carbon composite material according to claim 1, wherein the temperature of the carbon material subjected to the ultraviolet-ozone modification treatment is 100 to 180 ℃.
10. The method for preparing a silicon-carbon composite material according to claim 1, wherein the mass of the carbon material modified by ultraviolet-ozone at each time is 30-600 mg.
11. A silicon-carbon composite material prepared by the method for preparing a silicon-carbon composite material according to any one of claims 1 to 10.
12. A lithium ion battery, wherein an electrode of the lithium ion battery is mainly prepared from the silicon-carbon composite material according to claim 11.
CN202010946269.4A 2020-09-10 2020-09-10 Silicon-carbon composite material, preparation method thereof and lithium ion battery Active CN112002885B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010946269.4A CN112002885B (en) 2020-09-10 2020-09-10 Silicon-carbon composite material, preparation method thereof and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010946269.4A CN112002885B (en) 2020-09-10 2020-09-10 Silicon-carbon composite material, preparation method thereof and lithium ion battery

Publications (2)

Publication Number Publication Date
CN112002885A CN112002885A (en) 2020-11-27
CN112002885B true CN112002885B (en) 2022-03-01

Family

ID=73468512

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010946269.4A Active CN112002885B (en) 2020-09-10 2020-09-10 Silicon-carbon composite material, preparation method thereof and lithium ion battery

Country Status (1)

Country Link
CN (1) CN112002885B (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103539106A (en) * 2013-10-25 2014-01-29 苏州第一元素纳米技术有限公司 Preparation method of carbon material
CN104916826B (en) * 2015-07-03 2017-10-20 东莞市迈科科技有限公司 A kind of graphene coated silicium cathode material and preparation method thereof
KR101931143B1 (en) * 2015-10-15 2018-12-20 주식회사 엘지화학 Negative electrode active material and secondary battery comprising the same
CN106744671A (en) * 2016-11-30 2017-05-31 西南交通大学 A kind of monocrystalline silicon surface nanoprocessing method based on UV ozone
CN108598434A (en) * 2018-04-24 2018-09-28 盐城师范学院 A kind of electrostatic self-assembled preparation method of graphene/silicon electrode material
KR102153100B1 (en) * 2018-06-07 2020-09-07 재단법인 나노기반소프트일렉트로닉스연구단 Graphene laminate, method for preparing the same, and organic electronic device comprising the same
CN109390570B (en) * 2018-09-28 2022-03-15 深圳市八六三新材料技术有限责任公司 Graphene-coated silicon and preparation method and application thereof
CN110571425B (en) * 2019-09-24 2020-10-27 中国科学院化学研究所 Low-expansion-rate silicon-carbon composite material and preparation method thereof

Also Published As

Publication number Publication date
CN112002885A (en) 2020-11-27

Similar Documents

Publication Publication Date Title
Wang et al. Assembling carbon-coated α-Fe 2 O 3 hollow nanohorns on the CNT backbone for superior lithium storage capability
CN109524648B (en) Porous carbon nanofiber flexible battery material containing nano-silicon and preparation method thereof
Chen et al. Mesoporous single crystals Li 4 Ti 5 O 12 grown on rGO as high-rate anode materials for lithium-ion batteries
Jiang et al. A sustainable route from fly ash to silicon nanorods for high performance lithium ion batteries
Zhang et al. Bacteria-inspired fabrication of Fe3O4-carbon/graphene foam for lithium-ion battery anodes
CN103887480B (en) Graphene oxide and the self-assembled compound material of tetravalence vanadium oxyhydroxide
Zhang et al. Hierarchical architectured NiS@ SiO2 nanoparticles enveloped in graphene sheets as anode material for lithium ion batteries
JP2012511492A (en) Method for producing composite material of SnO2 and carbon nanotube and / or carbon nanofiber, material obtained by this method, and electrode of lithium battery including this material
Yin et al. Synthesis of SiO2@ carbon-graphene hybrids as anode materials of lithium-ion batteries
CN111446431A (en) Method for enhancing interface contact of silicon-oxygen-carbon cathode material of lithium ion battery through oxygen transfer reaction
CN113193185B (en) Silicon-carbon composite material, preparation method thereof and lithium ion battery
Thirugnanam et al. TiO2 nanoparticle embedded nitrogen doped electrospun helical carbon nanofiber-carbon nanotube hybrid anode for lithium-ion batteries
Yang et al. A surface multiple effect on the ZnO anode induced by graphene for a high energy lithium-ion full battery
CN106848282B (en) Negative electrode material for non-aqueous electrolyte secondary battery and preparation method and application thereof
Ji et al. High lithium storage of Co3O4 enabled by integrating hollow and porous carbon scaffolds
Chen et al. Core-shell structured Si@ Cu nanoparticles segregated in graphene-carbon nanotube networks enable high reversible capacity and rate capability of anode for lithium-ion batteries
US11001506B2 (en) Method of producing high performance lithium titanate anode material for lithium ion battery applications
Wang et al. 3D-structured carbon-coated MnO/graphene nanocomposites with exceptional electrochemical performance for Li-ion battery anodes
CN112002885B (en) Silicon-carbon composite material, preparation method thereof and lithium ion battery
CN106887591B (en) Composite conductive agent for lithium ion battery and preparation method thereof
WO2017123532A1 (en) Nanoparticle/porous graphene composite, synthesizing methods and applications of same
Zhang et al. Ultrafine SnO 2 nanoparticles decorated onto graphene for high performance lithium storage
CN113745483B (en) Hollow silicon-carbon-based composite material, preparation method thereof and negative electrode energy storage material for non-aqueous electrolyte secondary battery
Dong et al. Interconnected porous N-doped carbon coated cobalt/iron oxides core shell nanocomposites for superior lithium storage anode
KR102473743B1 (en) Manufacturing method of Graphene Quantum Dot/Silicone/Carbon nanomaterials Composites as Anode Materials for Lithiumion Batteries and Manufacturing method for Lithiumion Batteries using it

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