CN113451561A - Silicon-based composite material and preparation method and application thereof - Google Patents
Silicon-based composite material and preparation method and application thereof Download PDFInfo
- Publication number
- CN113451561A CN113451561A CN202110999775.4A CN202110999775A CN113451561A CN 113451561 A CN113451561 A CN 113451561A CN 202110999775 A CN202110999775 A CN 202110999775A CN 113451561 A CN113451561 A CN 113451561A
- Authority
- CN
- China
- Prior art keywords
- silicon
- carbon
- composite material
- based composite
- coating
- 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.)
- Granted
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
- H01M4/366—Composites as layered products
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/10—Carbon fluorides, e.g. [CF]nor [C2F]n
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/158—Carbon nanotubes
- C01B32/16—Preparation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/184—Preparation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/184—Preparation
- C01B32/186—Preparation by chemical vapour deposition [CVD]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/205—Preparation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
- C01B33/021—Preparation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/86—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by NMR- or ESR-data
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/10—Solid density
-
- 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
-
- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- 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-based composite material and a preparation method and application thereof. This combined material is by silicon and/or silicon oxide as the kernel, the surface of kernel is wrapped by the composite bed of carbon and carbon fluoride, this composite bed has continuous compact structure, the coating reduces by inside to outside carbon content gradually, carbon fluoride content increases gradually, the carbon fluoride coating effect that this kind of structure formed is better, in the battery cycle process, the fluorine on surface and the lithium reaction in the battery system generate lithium fluoride, the maintenance structural stability that the fluoridation interface ability of formation is better, reduce the emergence of side reaction, the thickness of SEI has been reduced, thereby effectively promote combined material's cyclicity ability.
Description
Technical Field
The invention relates to a silicon-based composite material and a preparation method thereof, in particular to application of the silicon-based composite material as a high specific energy lithium ion battery cathode material.
Background
With the wide application and rapid development of various portable electronic devices and electric automobiles, the demand and performance requirements for chemical power sources thereof are rapidly increased, and lithium ion batteries are widely applied to the field of mobile electronic terminal devices due to the advantages of large specific energy, high working voltage, small self-discharge rate and the like. And with the increase of the demand for high-energy power supplies, the lithium ion battery is developed towards higher energy density. At present, lithium iron phosphate/graphite systems are mostly adopted in commercial lithium ion batteries, and due to the low theoretical capacity of the electrodes of the systems, breakthrough progress is difficult to achieve by improving the battery preparation process to improve the battery performance. Generally, the total specific capacity of the lithium ion battery is determined by the specific capacity of the positive electrode material, the specific capacity of the negative electrode material and other components of the battery, wherein the specific capacities of the positive electrode material and the negative electrode material are the key for improving the total specific capacity of the lithium ion battery. Therefore, the development of novel high-specific-capacity lithium ion battery electrode materials is extremely urgent.
In the currently developed lithium ion battery cathode materials, the silicon-based materials are favored due to the lower potential and the extremely high theoretical capacity, but the silicon-based materials undergo severe volume change (volume change rate: 280-300%) in the process of lithium ion extraction and intercalation, so that the material structure is damaged and mechanically pulverized, the separation between electrode materials and the electrode material and a current collector is caused, and further the electrical contact is lost, so that the capacity is rapidly attenuated. Therefore, how to improve the cycle performance of the silicon-based anode material while obtaining high capacity is a major research point at present. In order to buffer the capacity fading caused by the huge volume change of silicon in the electrochemical process, various methods are adopted to improve the cyclicity of the silicon negative electrode material. The silica-based negative electrode material has larger irreversible capacity due to the formation of lithium oxide and lithium silicate in the process of lithium intercalation and deintercalation for the first time in the presence of oxygen, and the coulombic efficiency of the material is seriously reduced, but the lithium oxide and the lithium silicate can form a buffer layer in situ, so that the cycling stability of the silica-based negative electrode material can be improved. Only the volume change of the silicon monoxide is still not ignored, and an effective mode at present is to construct a fluorinated interface on the surface of the silicon monoxide negative electrode, maintain the structural integrity through interface protection, and prevent the uncontrolled growth of SEI through interface regulation so as to effectively improve the cycle stability of the silicon monoxide negative electrode material.
Patent CN109167031 discloses a nano silicon-carbon composite material and its preparation method, the silicon-carbon composite material of the invention has a multi-stage structure, taking silicon nanoparticles as an inner core, amorphous carbon as an intermediate coating layer, and carbon fluoride as an outer shell. The composite material with the multilevel structure is coated by carbon fluoride, so that the battery capacity and the first coulombic efficiency are effectively improved, and the composite material has excellent cycle performance, but the carbon fluoride is coated on the surface of silicon nanoparticles in a ball-milling physical mode in the preparation of the composite material, the coating surface has poor compactness, the oxidation problem caused by local overheating can be generated in the ball-milling process, a new interface is generated, and SEI continuously grows to cause the performance attenuation of the battery. In addition, the method for preparing the nano silicon by adopting the magnesiothermic reduction destroys the original silicon-oxygen structure of the silicon monoxide, can not effectively buffer the volume expansion and can also deteriorate the cycle performance of the battery.
Therefore, it is of great practical significance to develop a method for forming an effective fluorinated interface to actually improve various performances of the lithium battery on the basis of maintaining the excellent performances of the silicon-based material.
Disclosure of Invention
In order to solve the technical problems, the invention provides a silicon-based composite material coated with carbon fluoride and a preparation method thereof. The silicon-based composite material prepared by the method is used as a negative electrode material to be applied to a lithium ion battery, and can effectively improve the coulombic efficiency and the reversible capacity of the battery, so that the battery has more excellent cycle stability. And the silicon-based composite material is simple to prepare, is easy for industrial production and has wide application prospect.
In order to achieve the purpose, the invention provides a silicon-based composite material, the composite material takes silicon and/or silicon oxide as an inner core, the outer surface of the inner core is coated by a composite layer of carbon and carbon fluoride, the composite layer has a continuous and compact structure, the carbon content of the coating layer is gradually reduced from inside to outside, and the carbon fluoride content is gradually increased.
Preferably, the silicon is nano-silicon generated in situ from silicon oxide.
Preferably, the chemical formula of the silicon oxide is SiOxWherein 0 is<x<2, and the x value is the average value.
Preferably, the composite layer of carbon and carbon fluoride is prepared by two steps, wherein the first step is carbon coating, and the second step is converting a carbon-coated surface layer into a carbon fluoride-coated layer by fluorination treatment.
Preferably, the carbon in the composite layer of carbon and carbon fluoride may be amorphous carbon, graphitized carbon, carbon composite, etc., and is not limited to the above-mentioned exemplary substances, and other substances capable of achieving the same effect may also be used in the present invention.
The carbon coating method can be a solid phase coating method, a liquid phase coating method or a chemical vapor deposition method.
When the carbon coating method adopts a liquid phase or solid phase coating method, the coating layer can contain one or more of carbon nano tube, graphene, graphite alkyne and graphite.
When the carbon coating method adopts a chemical vapor coating method, the coating agent can be one or two of methane, acetylene, ethylene, propylene, methane, ethane, propane and natural gas or a combination of the carbon-containing gas and hydrogen (hydrogen is added, the carbon coating morphology is changed, such as a burr shape is formed), for example, a combination of methane and hydrogen, a combination of ethane and hydrogen, a combination of acetylene and hydrogen, a combination of natural gas and hydrogen, a combination of propane and hydrogen, a combination of ethylene and hydrogen, a combination of propylene and hydrogen, and the like, wherein the flow ratio of the carbon-containing gas to the hydrogen is 1: 3-5; the coating temperature of the gas phase coating is 400-1000 ℃, and preferably 700-950 ℃; the coating time of the gas phase coating is 1-6 h, preferably 3-5 h.
The fluorination treatment in the carbon fluoride coating can adopt fluorine-containing substances as fluorine sources. The fluorine-containing species is a fluoropolymer such as: fluorine-containing rubber, fluorine-containing polyimide, perfluoropolyether (PFPE), polyvinylidene fluoride (PVDF), vinylidene fluoride-based fluororubber (AFLAS), polytetrafluoroethylene, perfluoroalkoxyethylene polymer, polychlorotrifluoroethylene, polyhexafluoroisobutylene, polyhexafluoropropylene, poly (2, 2,3,3, 3-pentafluoropropylacrylate), poly (1, 1,1,3,3, 3-hexafluoroisopropyl acrylate), poly (2, 2,3,3,4,4, 4-heptafluorobutyl methacrylate). However, the present invention is not limited to the above-described examples, and other materials which can achieve the same effects can be used in the present invention.
The total mass of the silicon-based composite material is 100%, wherein the mass percent of carbon is 1-20%, and the mass percent of fluorine is 0.1-15%.
The silicon-based composite is a powder, and the median particle size of the powder particles is 0.1-100 [ mu ] m (e.g., 0.5, 1, 2 … … 10, 20, 30 … …, preferably 1-10 [ mu ] m.
A method for preparing a silicon-based composite material as defined in any of the above, comprising the steps of:
(1) adding silicon and silicon dioxide into a reactor according to a certain ratio (1: 1-3), preserving the heat for 1-30 h under the conditions that the vacuum degree is 0.01-100 Pa and the heating temperature is 600-1400 ℃, and obtaining silicon oxide after condensation and deposition.
(2) And crushing the silicon oxide into particles with the median diameter of 0.1-100 mu m, and then carrying out carbon coating to obtain the carbon-coated silicon-oxygen compound.
(3) Placing the carbon-coated silicon-oxygen compound at the downstream of a double-temperature-zone heating furnace, and placing a fluorine-containing substance at the upstream of the heating furnace; under inert atmosphere, at the upstream temperature of 1-20 ℃ min-1The heating rate of (1) is high-temperature heating to 700--1Heating to 400-600 ℃ at a high heating rate, carrying out heat preservation reaction for 0.5-5 h, and cooling to room temperature to obtain the silicon-based composite material. Preferably, the upstream is heated to 800-1000 ℃, the downstream is heated to 400-500 ℃, and the reaction time is kept at 2-4 hours.
The invention also provides the application of the silicon-based composite material or the silicon-based composite material prepared by the preparation method as a negative electrode material in a lithium ion battery, and the prepared lithium battery has high coulombic efficiency for the first time, high reversible capacity and excellent cycling stability.
Compared with the prior art, the silicon-based composite material for the lithium ion battery and the preparation method thereof have the advantages that: the silicon-based composite negative electrode material for the lithium ion battery, prepared by the invention, has the structure that nano silicon is dispersed in silicon oxide particles, and the surfaces of the particles are provided with carbon fluoride coating layers, fluorine is generated by pyrolysis of fluorine-containing substances in the carbon fluoride coating process, so that the fluorine and the carbon coating layers generate a thermal sealing reaction, and the carbon fluoride coating layers are formed in situ, so that the carbon fluoride and the carbon coating layers form a continuous and compact composite structure, the carbon content of the coating layers is gradually reduced from inside to outside, the carbon fluoride content is gradually increased, the carbon fluoride coating layers formed by the structure have better effect, in the battery circulation process, fluorine on the surfaces reacts with lithium in a battery system to generate lithium fluoride, a formed fluorinated interface can better maintain the structural stability, the occurrence of side reactions is reduced, the SEI thickness is reduced, and in addition, the carbon fluoride and carbon continuous transition structure enables the fusion of the carbon fluoride and the carbon to be better, the coating structure is more stable, and the rapid deterioration of the cycle performance caused by the damage of the carbon fluoride coating layer can not occur. In the present invention, it is also preferable to use a two-temperature zone furnace, in which the fluorine-containing polymer is placed upstream of the furnace and the carbon-coated silica composite is placed downstream of the furnace, so that the fluorine gas is generated and the generated fluorine gas reacts with the carbon coating layer of the silica composite under safer and more gentle conditions, thereby forming a coating layer structure in which carbon fluoride and carbon are continuously transferred. More preferably, by selecting the kind of the fluorine-containing polymer and setting the temperatures of the two temperature zones of the two-temperature zone heating furnace, on the one hand, a suitable coating structure can be obtained, and on the other hand, disproportionation of silicon oxide can be prevented.
Drawings
FIG. 1 is an X-ray diffraction spectrum of a silicon-based composite material prepared in example 1 of the present invention.
FIG. 2 shows a solid-state nuclear magnetic NMR spectrum of a silicon-based composite material obtained in example 1 of the present invention.
FIG. 3 is a SEM photograph of a silicon-based composite material obtained in example 1 of the present invention.
FIG. 4 is a TEM image of the Si-based composite material obtained in example 1 of the present invention.
Fig. 5 is a charge-discharge curve of the silicon-based composite material prepared in example 1 of the present invention as a negative electrode of a lithium ion battery.
Fig. 6 is a cycle performance curve of the silicon-based composite material prepared in example 1 of the present invention as a negative electrode of a lithium ion battery.
Detailed Description
The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.
The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.
The electrochemical properties of the silicon-based composite materials prepared in the following examples and comparative examples were as followsThe method comprises the following steps: mixing the prepared silicon-based composite material, carbon black, carboxymethyl cellulose (CMC) and Styrene Butadiene Rubber (SBR) composite binder in a mass ratio of 8:1:1 to prepare slurry (wherein the mass ratio of the CMC to the SBR is 2: 3), uniformly coating the slurry on a copper foil current collector, and performing vacuum drying for 12 hours to prepare a working electrode; 1 mol L of lithium flake as counter electrode, glass fiber membrane as separator-1 LiPF6(the solvent is a mixed solution of ethylene carbonate and dimethyl carbonate with the volume ratio of 1: 1) is used as an electrolyte, 5% of VC (ethylene carbonate) and 5% of FEC (fluoroethylene carbonate) are added into the electrolyte, and the button cell is assembled in an inert gas glove box in an argon atmosphere.
And (3) carrying out charge and discharge tests on the assembled battery on a LAND charge and discharge tester.
Example 1
(1) Mixing silicon simple substance and silicon dioxide according to the weight ratio of 1: 2, adding the mixture into a reactor, keeping the temperature for 20 hours under the conditions that the vacuum degree is 0.1 Pa and the heating temperature is 800 ℃, and condensing and depositing to obtain silicon oxide.
(2) Crushing the silicon oxide into particles with the particle size of 1-10 mu m, adding the particles into a reactor, placing the reactor in an inert atmosphere, and keeping the temperature at 10 ℃ for min-1Heating to 950 ℃ at a high heating rate, introducing hydrogen and methane gas (volume flow ratio is 1: 3) for surface carbon coating, carrying out coating and heat preservation for 2h, and cooling to room temperature to obtain the silica composite vertical to the graphene coating layer.
(3) Placing the carbon-coated silicon-oxygen compound at the downstream of a double-temperature-zone heating furnace, and placing polyvinylidene fluoride at the upstream, wherein the mass ratio of the silicon-oxygen compound to the polyvinylidene fluoride is 1: 10; under inert atmosphere, at 10 ℃ min upstream-1At a high temperature of 800 ℃ and at a downstream temperature of 10 ℃ min-1Heating to 500 ℃ at a high heating rate, preserving heat for 3 hours, and cooling to room temperature to obtain the silicon-based composite material.
The results of electrochemical tests of the material obtained in example 1 in button cells are given in table 1.
FIG. 1 is an XRD diffraction pattern of the silicon-based composite material obtained in example 1, wherein a diffraction peak of silicon is obvious and no other impurity peak exists.
FIG. 2 is an NMR chart of the silicon-based composite material obtained in example 1, and it can be seen that the composite material has a chemical structure of C-F.
FIG. 3 is an SEM image of the silicon-based composite material obtained in example 1, and it can be seen that the composite material is massive, has a dense surface and a uniform particle size, and has a particle size range of 1-10 μm.
Fig. 4 is a TEM image of the silicon-based composite material obtained in example 1, which shows that nano-silicon is present in the composite material, the particle size range is 1-20 nm, the carbon-carbon fluoride coating layer formed on the surface has a continuous and compact composite structure, a compact vertical graphene-structured carbon layer is present in the composite structure, the carbon content of the coating layer gradually decreases from inside to outside, and the carbon fluoride content gradually increases.
The electrochemical analysis test of the silicon-based composite material obtained by the invention is carried out, and the result is shown in figure 5. The charging and discharging interval is 0-1.5V, and the compaction density is 1.2 g cm-3At a current density of 190 mA g-1(0.1C) and the specific capacity of the material can reach 1620 mAh g-1The first-turn coulombic efficiency is 81.1%, and the capacity retention rate is 85.2% after 100 cycles (as shown in fig. 6), which proves that the composite material obtained by the invention has excellent cycle performance.
Example 2
The silicon-based composite material of the present invention was prepared in the same manner as in example 1, except that: and (3) removing the hydrogen treatment in the step (2). The other steps are the same as those of the silicon-based composite anode material obtained in the example 1.
Example 3
The silicon-based composite material of the present invention was prepared in the same manner as in example 1, except that: and (3) changing the methane gas in the step (2) into acetylene. The other steps are the same as those of the silicon-based composite material obtained in example 1.
Comparative example 1
The silicon-based composite material of the present invention was prepared in the same manner as in example 1, except that: and (4) removing the fluorination treatment in the step (3). The other steps are the same as those of the silicon-based composite anode material obtained in the example 1.
Comparative example 2
The other conditions are the same as the example 1, except that the carbon-coated silica composite obtained in the step (2) is mixed with carbon fluoride, and the mixture is subjected to ball milling to obtain the nano silicon-carbon composite material.
Example 4
The other conditions were the same as in example 1 except that:
(3) placing the carbon-coated silica composite at the downstream of a double-temperature-zone heating furnace, placing polyvinylidene fluoride at the upstream, and placing the polyvinylidene fluoride at the upstream at 10 ℃ per minute according to the mass ratio of 1:10 under the inert atmosphere-1At a high temperature of 1000 ℃ and at a downstream temperature of 10 ℃ min-1Heating to 500 ℃ at a high heating rate, preserving heat for 3 hours, and cooling to room temperature to obtain the silicon-based composite material.
Example 5
The other conditions were the same as in example 1 except that:
(3) placing the carbon-coated silica composite at the downstream of a double-temperature-zone heating furnace, placing polyvinylidene fluoride at the upstream, and placing the polyvinylidene fluoride at the upstream at 10 ℃ per minute according to the mass ratio of 1:10 under the inert atmosphere-1At a high temperature of 1000 ℃ and at a downstream temperature of 10 ℃ min-1Heating to 400 ℃ at a high heating rate, preserving the heat for 2 hours, and cooling to room temperature to obtain the silicon-based composite material.
Example 6
The other conditions were the same as in example 1 except that:
(3) placing the carbon-coated silicon-oxygen compound at the downstream of a two-temperature-zone heating furnace, placing polyvinylidene fluoride resin (PTFE) at the upstream according to the mass ratio of 1:10, and under the inert atmosphere, at the upstream temperature of 10 ℃ per minute-1At a high temperature of 800 ℃ and at a downstream temperature of 10 ℃ min-1Heating to 600 ℃ at a high heating rate, preserving the heat for 3 hours, and cooling to room temperature to obtain the silicon-based composite material.
Example 7
The other conditions were the same as in example 1, except that hydrogen and methane gas were introduced in step (2), and the volume flow ratio of hydrogen to methane was 1: 5.
example 8
The other conditions were the same as in example 1, except that hydrogen and methane gas were introduced in step (2), and the volume flow ratio of hydrogen to methane was 1: 6.
example 9
The other conditions were the same as in example 1 except that perfluoropolyether was used in place of polyvinylidene fluoride in step (3).
Example 10
The other conditions were the same as in example 1 except that chlorotrifluoroethylene was used in place of polyvinylidene fluoride in step (3).
Example 11
The other conditions were the same as in example 1 except that polytetrafluoroethylene was used in place of polyvinylidene fluoride in step (3).
Example 12
The other conditions were the same as in example 1, except that in step (3), the reaction mixture was changed by mixing the components in a mass ratio of 1:1 in place of polyvinylidene fluoride.
Example 13
The other conditions were the same as in example 4, except that in step (3), the reaction mixture was changed to a mixture of 1:1 in place of polyvinylidene fluoride.
Example 14
The other conditions were the same as in example 5, except that in step (3), the reaction mixture was changed to a mixture of 1:1 in place of polyvinylidene fluoride.
It can be seen from the above that, for the silicon-based negative electrode material without pre-lithiation, higher cycle stability is also realized, and compared with the prior art, the improvement is more than 20%.
The applicant states that the present invention is illustrated by the above examples to describe the detailed preparation method of the present invention, but the present invention is not limited to the above detailed preparation method, i.e. it does not mean that the present invention must rely on the above detailed preparation method to be carried out. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. A silicon-based composite material, which takes silicon and/or silicon oxide as an inner core, and the outer surface of the inner core is coated by a composite layer of carbon and carbon fluoride, is characterized in that: the composite layer has a continuous and compact structure, the carbon content of the coating layer is gradually reduced from inside to outside, and the carbon fluoride content is gradually increased.
2. The silicon-based composite material of claim 1, wherein: the silicon is nano-silicon generated in situ from silicon oxide.
3. The silicon-based composite material of claim 1, wherein: the chemical formula of the silicon oxide is SiOxWherein 0 is<x<2, and the x value is the average value.
4. The silicon-based composite material of claim 1, wherein: the composite layer of carbon and carbon fluoride is prepared by two steps, wherein the first step is carbon coating, and the second step is converting a carbon coating surface layer into a carbon fluoride coating layer through fluorination treatment.
5. The silicon-based composite material of claim 4, wherein: the carbon coating method adopts a liquid phase or solid phase coating method, and the coating layer contains one or more of carbon nano tube, graphene, graphite alkyne and graphite.
6. The silicon-based composite material of claim 4, wherein: the carbon coating method adopts a chemical vapor coating method, and the coating agent is one or the combination of two of methane, acetylene, ethylene, propylene, ethane, propane and natural gas, or the combination of the gases and hydrogen; the coating temperature of the gas phase coating is 400-1000 ℃; the coating time of the gas phase coating is 1-6 h.
7. The silicon-based composite material of claim 1, wherein: the total mass of the silicon-based composite material is 100%, wherein the mass percent of carbon is 1-20%, and the mass percent of fluorine is 0.1-15%.
8. The silicon-based composite material of claim 1, wherein: the silicon-based composite material is powdery, and the median particle size of the powder is 1-10 mu m.
9. Process for the preparation of a silicon-based composite material according to any one of claims 1 to 8, comprising the following steps:
(1) adding simple substances or compounds of silicon and silicon dioxide into a reactor according to a certain proportion, preserving the heat for 1-30 h under the conditions that the vacuum degree is 0.01-100 Pa and the heating temperature is 600-1400 ℃, and obtaining silicon oxide after condensation and deposition;
(2) crushing the silicon oxide into particles with the particle size of 0.1-100 mu m, and then carrying out carbon coating to obtain a carbon-coated silicon-oxygen compound;
(3) placing the carbon-coated silica composite at the downstream of a double-temperature-zone heating furnace, and placing a fluorine-containing substance at the upstream; under inert atmosphere, at the upstream temperature of 1-20 ℃ min-1The heating rate is high-temperature heating to 700--1Heating to 400-600 ℃ at a high heating rate, preserving the heat for 0.5-5 h, and cooling to room temperature to obtain the silicon-based composite material.
10. Use of the silicon-based composite material according to any one of claims 1 to 8 as a negative electrode material in a lithium ion battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110999775.4A CN113451561B (en) | 2021-08-30 | 2021-08-30 | Silicon-based composite material and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110999775.4A CN113451561B (en) | 2021-08-30 | 2021-08-30 | Silicon-based composite material and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113451561A true CN113451561A (en) | 2021-09-28 |
| CN113451561B CN113451561B (en) | 2022-02-15 |
Family
ID=77818865
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110999775.4A Active CN113451561B (en) | 2021-08-30 | 2021-08-30 | Silicon-based composite material and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113451561B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114551844A (en) * | 2022-03-01 | 2022-05-27 | 深圳博磊达新能源科技有限公司 | Lithium titanate composite negative electrode material and preparation method thereof |
| CN114899371A (en) * | 2022-04-29 | 2022-08-12 | 佛山市德方纳米科技有限公司 | Low-water-content cathode material, preparation method thereof and lithium ion battery |
| CN115799474A (en) * | 2022-12-13 | 2023-03-14 | 大连理工大学 | Preparation method and application of fluorinated silicon-carbon negative electrode material |
| WO2023241166A1 (en) * | 2022-06-17 | 2023-12-21 | 珠海冠宇电池股份有限公司 | Electrode plate, battery cell, and battery |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109167031A (en) * | 2018-08-21 | 2019-01-08 | 浙江大学 | A kind of nano-silicone wire/carbon composite material and its preparation method and application |
| CN109167032A (en) * | 2018-08-21 | 2019-01-08 | 浙江大学 | A kind of nano silicon-based composite material and preparation method and application |
| EP3444876A1 (en) * | 2016-04-15 | 2019-02-20 | Huawei Technologies Co., Ltd. | Silicon negative electrode material, preparation method therefor, negative electrode plate, and lithium-ion battery |
| CN110880599A (en) * | 2018-09-06 | 2020-03-13 | 天津大学 | Preparation method of high-performance fluorinated peanut shell hard carbon electrode material |
| CN111082006A (en) * | 2019-12-06 | 2020-04-28 | 深圳市比克动力电池有限公司 | Silicon monoxide composite negative electrode material, preparation method thereof and lithium ion battery |
| CN111276675A (en) * | 2018-12-04 | 2020-06-12 | 中国科学院宁波材料技术与工程研究所 | Modified silicon-carbon material and preparation method and application thereof |
| CN112002881A (en) * | 2020-07-30 | 2020-11-27 | 国网浙江省电力有限公司电力科学研究院 | Hard carbon composite material and preparation method and application thereof |
-
2021
- 2021-08-30 CN CN202110999775.4A patent/CN113451561B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3444876A1 (en) * | 2016-04-15 | 2019-02-20 | Huawei Technologies Co., Ltd. | Silicon negative electrode material, preparation method therefor, negative electrode plate, and lithium-ion battery |
| CN109167031A (en) * | 2018-08-21 | 2019-01-08 | 浙江大学 | A kind of nano-silicone wire/carbon composite material and its preparation method and application |
| CN109167032A (en) * | 2018-08-21 | 2019-01-08 | 浙江大学 | A kind of nano silicon-based composite material and preparation method and application |
| CN110880599A (en) * | 2018-09-06 | 2020-03-13 | 天津大学 | Preparation method of high-performance fluorinated peanut shell hard carbon electrode material |
| CN111276675A (en) * | 2018-12-04 | 2020-06-12 | 中国科学院宁波材料技术与工程研究所 | Modified silicon-carbon material and preparation method and application thereof |
| CN111082006A (en) * | 2019-12-06 | 2020-04-28 | 深圳市比克动力电池有限公司 | Silicon monoxide composite negative electrode material, preparation method thereof and lithium ion battery |
| CN112002881A (en) * | 2020-07-30 | 2020-11-27 | 国网浙江省电力有限公司电力科学研究院 | Hard carbon composite material and preparation method and application thereof |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114551844A (en) * | 2022-03-01 | 2022-05-27 | 深圳博磊达新能源科技有限公司 | Lithium titanate composite negative electrode material and preparation method thereof |
| CN114899371A (en) * | 2022-04-29 | 2022-08-12 | 佛山市德方纳米科技有限公司 | Low-water-content cathode material, preparation method thereof and lithium ion battery |
| CN114899371B (en) * | 2022-04-29 | 2024-03-19 | 深圳市德方纳米科技股份有限公司 | Low-water-content positive electrode material, preparation method thereof and lithium ion battery |
| WO2023241166A1 (en) * | 2022-06-17 | 2023-12-21 | 珠海冠宇电池股份有限公司 | Electrode plate, battery cell, and battery |
| CN115799474A (en) * | 2022-12-13 | 2023-03-14 | 大连理工大学 | Preparation method and application of fluorinated silicon-carbon negative electrode material |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113451561B (en) | 2022-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110615423B (en) | Preparation method of silicon-based composite negative electrode material of lithium battery | |
| CN113451561B (en) | Silicon-based composite material and preparation method and application thereof | |
| CN108054351B (en) | Lithium ion battery, silicon-carbon negative electrode material used by lithium ion battery and preparation method of silicon-carbon negative electrode material | |
| CN110212183B (en) | Powder pre-lithiation silicon-based negative electrode material and preparation method and application thereof | |
| CN107946576B (en) | High-rate graphite negative electrode material, preparation method thereof and lithium ion battery | |
| CN107221654B (en) | Three-dimensional porous nest-shaped silicon-carbon composite negative electrode material and preparation method thereof | |
| CN111048770B (en) | Ternary doped silicon-based composite material and preparation method and application thereof | |
| CN112133896B (en) | High-capacity graphite-silicon oxide composite material and preparation method and application thereof | |
| CN110635116B (en) | Lithium ion battery cathode material, preparation method thereof, cathode and lithium ion battery | |
| CN111009647A (en) | Lithium borosilicate alloy cathode active material of lithium secondary battery, cathode, preparation and application thereof | |
| CN113555539A (en) | High-energy-density quick-charging graphite composite negative electrode material, preparation method thereof and lithium ion battery | |
| CN115714170B (en) | Preparation method of high-energy-density quick-charge anode material | |
| CN112234181A (en) | Two-dimensional silicon oxide/carbon composite lithium ion battery cathode material and preparation method thereof | |
| CN108448114A (en) | A kind of soft carbon negative electrode material of lithium ion battery and preparation method thereof | |
| CN115207329A (en) | Preparation method of high-energy-density silicon carbon/mesocarbon microbead composite material | |
| CN113889594A (en) | Preparation method of boron-doped lithium lanthanum zirconate-coated graphite composite material | |
| CN112928246A (en) | Composite material, preparation method and application thereof | |
| CN110299514B (en) | Core-shell structure silicon-carbon negative electrode material, preparation method and negative electrode plate | |
| CN114242961A (en) | Graphene/silicon oxide-coated nano-silicon composite material, and preparation method and application thereof | |
| CN114300671A (en) | Graphite composite negative electrode material and preparation method and application thereof | |
| CN108767249B (en) | Preparation method of hard carbon electrode material | |
| CN114784233A (en) | Negative electrode active material and preparation method and application thereof | |
| CN113942991A (en) | Silicon carbon-graphite composite negative electrode material and preparation method thereof | |
| CN112968155A (en) | Composite negative electrode material for lithium ion battery and preparation method thereof | |
| CN111646501B (en) | Preparation method of vertical graphene sheet-Ti 2O3-C composite microsphere, product and application thereof |
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 |