CN113690420B - Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof - Google Patents

Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof Download PDF

Info

Publication number
CN113690420B
CN113690420B CN202110987057.5A CN202110987057A CN113690420B CN 113690420 B CN113690420 B CN 113690420B CN 202110987057 A CN202110987057 A CN 202110987057A CN 113690420 B CN113690420 B CN 113690420B
Authority
CN
China
Prior art keywords
nitrogen
sulfur
composite material
carbon
doped silicon
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
CN202110987057.5A
Other languages
Chinese (zh)
Other versions
CN113690420A (en
Inventor
郑淞生
王旖婷
凡正清
王兆林
陈思
张叶涵
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.)
Xiamen University
Original Assignee
Xiamen University
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 Xiamen University filed Critical Xiamen University
Priority to CN202110987057.5A priority Critical patent/CN113690420B/en
Publication of CN113690420A publication Critical patent/CN113690420A/en
Application granted granted Critical
Publication of CN113690420B publication Critical patent/CN113690420B/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
    • H01M4/366—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
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • 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
    • 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 nitrogen-sulfur doped silicon-carbon composite material, a preparation method thereof and application of the composite material to a lithium ion battery cathode, and belongs to the technical field of electrode materials. The nitrogen-sulfur-doped silicon-carbon composite material provided by the invention comprises submicron silicon and a nitrogen-sulfur-doped carbon polymer layer coated on the surface of the submicron silicon; copper nanoparticles are dispersed in the nitrogen-sulfur doped carbon polymer layer. The existence of nitrogen in the nitrogen-sulfur-doped silicon-carbon composite material provided by the invention can replace carbon atoms in a carbon material lattice and introduce holes or defects into the structure, the existence of sulfur can improve the positive charge density of adjacent carbon atoms, and the existence of Faraday reaction enables more lithium storage sites to be generated in the nitrogen-sulfur-doped silicon-carbon composite material, so that the specific capacity, the conductive capability and the cycling stability of the nitrogen-sulfur-doped silicon-carbon composite material are improved, the conductivity between the composite material and a current collector is greatly improved, and the electrochemical performance of a lithium ion battery is effectively improved.

Description

Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof
Technical Field
The invention relates to the technical field of electrode materials, in particular to a nitrogen-sulfur doped silicon-carbon composite material and a preparation method and application thereof.
Background
Graphite or graphitized carbon is widely used as a negative electrode material of the existing commercial lithium ion battery. At present, the practical application capacity of the carbon negative electrode material reaches 350mAh/g and is close to LiC 6 Theoretical value of (372 mAh/g). The lithium ion battery cathode material will develop towards the direction of high specific capacity, high charge-discharge efficiency, high cycle performance and lower cost in the future, therefore, the graphite material cannot meet the requirements of the lithium ion battery in the futureHigh specific capacity application requirements in the electric automobile industry and the energy storage field.
The theoretical lithium capacity of silicon can reach 4200mAh/g (corresponding to Li) 4.4 Si) is more than ten times of that of the graphite material (with the theoretical capacity of 372 mAh/g), and is also far higher than other metal oxide negative electrode materials. Under the condition of normal temperature, the highest component formed after Si inserts lithium is Li 15 Si 4 (Li 3.75 Si) with theoretical lithium capacity up to 3579mAh/g. And the lithium insertion potential of silicon is about<0.5V(vs.Li/Li + ) Higher than that of the graphite negative electrode material (<0.2Vvs.Li/Li + ) Therefore, lithium is not easy to precipitate on the silicon surface in the charging and discharging process, thereby improving the safety of the battery. Moreover, silicon is abundant in earth crust, low cost, non-toxic, and has stable chemical properties. Therefore, the silicon is an ideal lithium ion battery cathode material and has a good prospect. However, si will undergo a large volume change during lithium intercalation and deintercalation (e.g., li) 15 Si 4 Corresponding volume change of 266%), resulting in the cycling stability of lithium ion batteries with silicon material as the negative electrode being affected.
Disclosure of Invention
In view of this, the present invention provides a nitrogen-sulfur-doped silicon-carbon composite material, and a preparation method and an application thereof, and a lithium ion battery prepared from the nitrogen-sulfur-doped silicon-carbon composite material has excellent cycle stability.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a nitrogen-sulfur-doped silicon-carbon composite material, which comprises submicron silicon and a nitrogen-sulfur-doped carbon polymer layer coated on the surface of the submicron silicon;
the nitrogen-sulfur-doped carbon polymer layer is obtained by polymerizing a carbon source and a nitrogen-sulfur source.
Preferably, the particle size of the nitrogen-sulfur doped silicon-carbon composite material is 1-10 μm.
Preferably, the carbon source comprises one or more of alkane compounds, phenyl compounds, glucose, starch and cellulose;
the nitrogen-sulfur source is nitrogen-sulfur-containing amino acid.
Preferably, the thickness of the nitrogen-sulfur doped carbon polymer layer is 0.5 to 9.5 μm.
The invention provides a preparation method of the nitrogen-sulfur doped silicon-carbon composite material, which comprises the following steps:
mixing a carbon source, a nitrogen and sulfur source, submicron silicon and water, adjusting the pH value to 1-3, and carrying out hydrothermal reaction to obtain the nitrogen and sulfur doped silicon-carbon composite material.
Preferably, the mass ratio of nitrogen in the carbon source, the submicron silicon and the nitrogen-sulfur source to sulfur in the nitrogen-sulfur source is 1: (0.1-3): (0.01-0.15): (0.01-0.20).
Preferably, the temperature of the hydrothermal reaction is 120-210 ℃, and the holding time is 2-16 h.
The invention provides the application of the nitrogen-sulfur-doped silicon-carbon composite material or the nitrogen-sulfur-doped silicon-carbon composite material prepared by the preparation method in the technical scheme in a lithium ion battery.
The invention provides a lithium ion battery cathode, which comprises a current collector and an active substance layer loaded on the surface of the current collector;
the active material layer comprises the nitrogen-sulfur-doped silicon-carbon composite material or the nitrogen-sulfur-doped silicon-carbon composite material obtained by the preparation method, a conductive agent and an adhesive.
Preferably, the thickness of the active material layer is 50 to 300 μm.
The invention provides a nitrogen-sulfur-doped silicon-carbon composite material, which comprises submicron silicon and a nitrogen-sulfur-doped carbon polymer layer coated on the surface of the submicron silicon; copper nanoparticles are dispersed in the nitrogen-sulfur doped carbon polymer layer. In the nitrogen-sulfur doped silicon-carbon composite material provided by the invention, the radiuses of nitrogen atoms and carbon atoms are close, and the chemical properties are similar, so that the carbon atoms in the carbon material crystal lattice are easily replaced, cavities or defects can be introduced into the structure, and the specific surface area of the material is improved; because the nuclear electron of the nitrogen atom is one more than that of the carbon atom and has higher electron affinity, the positive charge density of the carbon atom adjacent to the nitrogen atom in the nitrogen-sulfur doped silicon-carbon composite material is improved, and the nitrogen atom maintaining lone-pair electrons can also improve the electrochemical performance of the composite material in a mode of conjugated of the lone-pair electrons and pi bonds in the carbon atom lattice. The sulfur atom is easy to polarize lone pair electrons, so that the positive charge density of adjacent carbon atoms can be improved, and more lithium storage sites are generated in the nitrogen-sulfur doped silicon-carbon composite material due to the Faraday reaction, so that the specific capacity and the conductive capacity of the nitrogen-sulfur doped silicon-carbon composite material are improved, and the electrochemical performance of the carbon material is improved. In addition, a synergistic effect exists between nitrogen and sulfur heteroatoms in the nitrogen-sulfur doped silicon-carbon composite material, so that the specific capacity, the conductive capacity and the cycling stability of the carbon material can be improved together.
The invention provides a preparation method of the nitrogen-sulfur doped silicon-carbon composite material. The preparation method provided by the invention has the advantages of wide source of used raw materials, low price, adoption of one-step hydrothermal reaction, no need of secondary high-temperature carbonization treatment, simple and convenient operation, low cost, low energy consumption and low pollution, and has the potential of industrial production. Moreover, the overall conductivity of the prepared nitrogen-sulfur doped silicon-carbon composite material is improved, and the defect of low conductivity of silicon is effectively overcome; meanwhile, the silicon-based negative electrode shows poor cycling stability and rapid performance attenuation due to the huge volume change problem in the charging and discharging processes, and the nitrogen-sulfur-doped silicon-carbon composite material prepared by the invention shows excellent cycling stability and good rapid charging and discharging capacity, which shows that the nitrogen-sulfur-doped silicon-carbon composite material provided by the invention relieves the volume expansion problem of silicon to a certain extent.
Drawings
FIG. 1 is an SEM image of composite materials prepared in example 1 and comparative example 1, wherein (a) and (b) are example 1 and (c) and (d) are comparative example 1;
FIG. 2 is an XRD pattern of the composite materials prepared in example 1 and comparative example 1;
FIG. 3 is an infrared spectrum of the composite materials prepared in example 1 and comparative example 1;
fig. 4 is a graph comparing the constant current performance of the button-type half cells prepared in example 4 and comparative example 2;
fig. 5 is a graph comparing rate performance of button-type half cells prepared in example 4 and comparative example 2;
fig. 6 is a graph comparing the ac impedance of the button-type half cells prepared in example 4 and comparative example 2.
Detailed Description
The invention provides a nitrogen-sulfur-doped silicon-carbon composite material, which comprises submicron silicon and a nitrogen-sulfur-doped carbon polymer layer coated on the surface of the submicron silicon; the nitrogen-sulfur-doped carbon polymer layer is obtained by polymerizing a carbon source and a nitrogen-sulfur source.
In the present invention, the particle size of the nitrogen-sulfur doped silicon-carbon composite material is 1 to 10 μm, more preferably 1 to 8 μm, and most preferably 1 to 6 μm. In the present invention, the particle size of the submicron-sized silicon is preferably 1 μm or less, more preferably 500nm or less, and most preferably 100nm or less.
In the invention, the nitrogen-sulfur-doped carbon polymer layer is obtained by polymerizing a carbon source and a nitrogen-sulfur source. In the present invention, the carbon source preferably includes one or more of alkane compound, phenyl compound, glucose, starch and cellulose; the glucose preferably comprises one or more of D- (+) -glucose, D- (+) -glucose monohydrate and L- (-) -glucose; when the carbon source is a mixture of two or more carbon sources, the mass ratio of the different carbon sources is not particularly limited, and any ratio may be used. In the invention, the nitrogen sulfur source is preferably nitrogen sulfur-containing amino acid, and the nitrogen sulfur-containing amino acid preferably comprises one or more of cysteine, sulfamic acid, sulfanilamide and methionine; when the nitrogen sulfur source is a mixture of more than two nitrogen sulfur sources, the mass ratio of different nitrogen sulfur sources is not particularly limited, and the nitrogen sulfur sources can be in any proportion. In the present invention, the thickness of the nitrogen-sulfur doped carbon polymer layer is preferably 0.5 to 9.5 μm, more preferably 1 to 7.5 μm, and most preferably 3 to 5.5 μm.
In the invention, the mass ratio of nitrogen to sulfur in the nitrogen-sulfur doped carbon polymer layer is (1-15): (1 to 20), more preferably (5 to 10): (5-15).
The invention provides a preparation method of the nitrogen-sulfur doped silicon-carbon composite material, which comprises the following steps:
mixing a carbon source, a nitrogen and sulfur source, submicron silicon and water, adjusting the pH value to 1-3, and carrying out hydrothermal reaction to obtain the nitrogen and sulfur doped silicon-carbon composite material.
In the present invention, unless otherwise specified, all the raw material components are commercially available products well known to those skilled in the art.
In the present invention, the carbon source and the nitrogen-sulfur source are preferably the same as those described above, and are not described herein again.
In the present invention, the particle size of the submicron silicon is preferably the same as that of the submicron silicon, and will not be described herein. In the invention, the submicron silicon is preferably one or more of commercial silicon, photovoltaic silicon and waste silicon; the shape of the submicron-sized silicon preferably includes a granular shape, a flake shape or a needle shape; the scrap silicon is preferably sourced from the photovoltaic industry; when the submicron silicon is a mixture of commercial silicon and waste silicon, the mass ratio of the commercial silicon to the waste silicon is not particularly limited in the present invention, and any ratio may be used.
In the present invention, the mass ratio of nitrogen in the carbon source, the submicron-sized silicon, and the nitrogen-sulfur source to sulfur in the nitrogen-sulfur source is preferably 1: (0.1-3): (0.01-0.15): (0.01 to 0.20), 1: (0.5-2.5): (0.03-0.12): (0.05-0.15); most preferably 1: (1-1.5): (0.05-0.10): (0.1-0.12).
In the invention, the pH regulator used for regulating the pH value is preferably an acidic reagent and/or an alkaline reagent, and the acidic reagent preferably comprises one or more of sulfuric acid, hydrochloric acid and phosphoric acid; the alkaline reagent preferably comprises one or more of ammonia water, sodium hydroxide and potassium hydroxide; the concentration of the ammonia water is preferably 20 to 30wt%, and more preferably 25 to 28wt%; the amount of the pH adjuster is not particularly limited, and the pH of the system can be adjusted to 1 to 3, and the pH is more preferably 2; in the embodiment of the present invention, the mass of the pH adjuster is preferably 5 to 60%, more preferably 10 to 50%, and most preferably 20 to 30% of the mass of water.
In the present invention, the ratio of the amount of the substance of the carbon source to the volume of water is preferably 0.1 to 10mol:1L, more preferably 0.5 to 8mol:1L, most preferably 2 to 5mol:1L of the compound.
The mixing mode is not particularly limited, and the raw materials can be uniformly mixed, specifically, ultrasonic mixing is adopted.
In the present invention, the temperature of the hydrothermal reaction is preferably 120 to 210 ℃, more preferably 150 to 200 ℃, and most preferably 170 to 200 ℃; the heating rate of the temperature from room temperature to the hydrothermal reaction temperature is preferably 5-20 ℃/min, more preferably 5-15 ℃/min, and most preferably 10-15 ℃/min; starting timing when the temperature is increased to the temperature of the hydrothermal reaction, the heat preservation time of the hydrothermal reaction is preferably 2-16 h, more preferably 4-12 h, and most preferably 5-10 h; the hydrothermal reaction is preferably carried out in a hydrothermal kettle; the hydrothermal reaction is preferably carried out under the condition of stirring, the stirring speed is not particularly limited, and the hydrothermal reaction can be ensured to be carried out smoothly; the pressure of the hydrothermal reaction is preferably the saturated vapor pressure of water at the temperature of the hydrothermal reaction; in the hydrothermal reaction process, a carbon source and a nitrogen-sulfur source are subjected to polymerization reaction and successfully wrapped on the surface of the submicron silicon particles to form spherical particles with nitrogen-sulfur doped carbon shells. The preparation method provided by the invention can realize the controllable synthesis of the composite material, can improve the overall conductivity of the composite material by nitrogen-sulfur double doping, does not need secondary high-temperature carbonization treatment, is simple and convenient to operate, has low cost, low energy consumption and low pollution, and has the potential of industrial production.
After the hydrothermal reaction, the method preferably further comprises the step of carrying out post-treatment on a product system after the hydrothermal reaction, wherein the post-treatment preferably comprises the following steps; and cooling to room temperature, carrying out solid-liquid separation, and sequentially washing, drying and grinding the obtained solid product to obtain the nitrogen-sulfur doped silicon-carbon composite material. The cooling method of the present invention is not particularly limited, and those skilled in the art can use a cooling method, such as natural cooling. The solid-liquid separation mode of the invention is not particularly limited, and those skilled in the art are familiar with the solid-liquid separation mode, such as suction filtration or centrifugal separation. In the invention, the washing comprises water washing and alcohol washing in sequence, wherein the water washing is preferably deionized water washing; the alcohol washing is preferably absolute alcohol washing; in the present invention, the number of times of the water washing and the alcohol washing is not particularly limited, and it is sufficient to remove unreacted carbon source, nitrogen and sulfur source, and pH adjuster. In the present invention, the drying temperature is preferably 50 to 120 ℃, more preferably 70 to 90 ℃; in the present invention, the drying time is not particularly limited, and the drying time may be set to a constant weight. The grinding mode is not particularly limited, and the particle size of the nitrogen-sulfur doped silicon-carbon composite material can be 1-10 mu m; the purpose of the grinding is to reduce agglomeration of the nitrogen-sulfur doped silicon-carbon composite material.
The invention also provides the application of the nitrogen-sulfur-doped silicon-carbon composite material in the technical scheme or the nitrogen-sulfur-doped silicon-carbon composite material prepared by the preparation method in the technical scheme in a lithium ion battery. In the invention, the nitrogen-sulfur-doped silicon-carbon composite material is preferably used as a negative electrode material of a lithium ion battery.
The invention also provides a lithium ion battery cathode which comprises a current collector and an active material layer loaded on the surface of the current collector. In the present invention, the current collector is preferably a metal conductor material, and more preferably includes a copper foil, a nickel foil, or a stainless steel foil. In the invention, the active material layer comprises the nitrogen-sulfur-doped silicon-carbon composite material described in the above technical scheme or the nitrogen-sulfur-doped silicon-carbon composite material obtained by the preparation method described in the above technical scheme, a conductive agent and an adhesive. In the present invention, the conductive agent preferably includes one or more of conductive carbon black, acetylene black, conductive graphite, carbon nanotubes, and graphene. In the invention, the binder preferably comprises one or more of polyacrylic acid, sodium alginate, polyvinylidene fluoride and polyvinylpyrrolidone. In the invention, the mass ratio of the nitrogen-sulfur doped silicon-carbon composite material to the conductive agent to the adhesive is preferably (3-8): 1:0.5 to 1.5, more preferably (4 to 7): 1:0.8 to 1.2, most preferably (5 to 6): 1:1. in the present invention, the thickness of the active material layer is preferably 50 to 300. Mu.m, more preferably 100 to 250. Mu.m, and most preferably 150 to 200. Mu.m.
In the present invention, the method for preparing the lithium ion battery negative electrode preferably includes the following steps: mixing the nitrogen-sulfur doped silicon-carbon composite material, a conductive agent, an adhesive and water to obtain negative electrode slurry; and coating the negative electrode slurry on the surface of the current collector to obtain the lithium ion battery negative electrode.
The invention mixes the nitrogen-sulfur doped silicon-carbon composite material, a conductive agent, a binding agent and water to obtain the cathode slurry. The invention has no special limit on the using amount of the water, and the viscosity of the cathode slurry can meet the standard of the conventional lithium battery slurry. In the embodiment of the present invention, the mass ratio of the solid material to the water in the anode slurry is preferably 1:8 to 20, more preferably 1:10 to 15; the solid material comprises a nitrogen-sulfur doped silicon-carbon composite material, a conductive agent and a bonding agent. In the present invention, the mixing is preferably performed under stirring conditions, and the mixing time is preferably 6 to 12 hours, more preferably 8 to 10 hours; the stirring rate is not particularly limited in the present invention, and the stirring may be performed at a stirring rate known to those skilled in the art.
After the negative electrode slurry is obtained, the negative electrode slurry is coated on the surface of a current collector to obtain the negative electrode of the lithium ion battery. The current collector is not particularly limited in the present invention, and a current collector known to those skilled in the art may be used, specifically, a copper foil. The coating method of the present invention is not particularly limited, and may be a coating method known to those skilled in the art. After the coating is finished, the invention preferably dries the coated active material wet layer to obtain the lithium ion battery cathode; in the present invention, the thickness of the active material wet layer is preferably 50 to 300. Mu.m, more preferably 100 to 250. Mu.m, and most preferably 150 to 200. Mu.m; the drying mode is preferably vacuum drying, and the drying temperature is preferably 50-110 ℃, more preferably 70-100 ℃, and most preferably 70-90 ℃; the drying time is preferably 6 to 48 hours, more preferably 10 to 40 hours, and most preferably 20 to 30 hours.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the 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.
Example 1
Uniformly mixing 4.5g of glucose, 2g of silicon with the particle size of 470nm and 1.2g L-cysteine, adding 5mL of concentrated sulfuric acid (with the concentration of 98 wt%) and 45mL of deionized water, ultrasonically dispersing and mixing for 10min, heating from room temperature to 180 ℃ at the heating rate of 10 ℃/min, carrying out heat preservation hydrothermal reaction for 6h, cooling to room temperature, carrying out solid-liquid separation, sequentially washing the obtained solid product with deionized water and absolute ethyl alcohol, drying to constant weight at 70 ℃, and grinding to be free of agglomeration to obtain the nitrogen-sulfur-doped silicon-carbon composite material (marked as cysS) with the particle size of 2-7 mu m, wherein the thickness of the nitrogen-sulfur-doped carbon polymer layer is 1.5-6.5 mu m.
Example 2
Uniformly mixing 5g of glucose, 3g of silicon with the particle size of 480nm and 2g of sulfamic acid, adding 10mL of concentrated sulfuric acid (with the concentration of 98 wt%) and 40mL of deionized water, carrying out ultrasonic dispersion and mixing for 10min, heating from room temperature to 170 ℃ at the heating rate of 5 ℃/min, carrying out thermal insulation hydrothermal reaction for 10h, cooling to room temperature, carrying out solid-liquid separation, sequentially washing the obtained solid product with deionized water and absolute ethyl alcohol, drying at 70 ℃ to constant weight, grinding until no agglomeration exists, and obtaining the nitrogen-sulfur-doped silicon-carbon composite material with the particle size of 2-7 mu m, wherein the thickness of the nitrogen-sulfur-doped carbon polymer layer is 1.5-6.5 mu m.
Example 3
Uniformly mixing 5g of glucose, 2.8g of silicon with the particle size of 500nm and 1g of methionine, adding 10mL of ammonia water (with the concentration of 28 wt%) and 40mL of deionized water, ultrasonically dispersing and mixing for 10min, heating from room temperature to 190 ℃ at the heating rate of 15 ℃/min, carrying out heat preservation hydrothermal reaction for 8h, cooling to room temperature, carrying out solid-liquid separation, sequentially washing the obtained solid product with deionized water and absolute ethyl alcohol, drying at 60 ℃ to constant weight, grinding until no agglomeration exists, and obtaining the nitrogen-sulfur-doped silicon-carbon composite material with the particle size of 2-7 mu m, wherein the thickness of the nitrogen-sulfur-doped carbon polymer layer is 1.5-6.5 mu m.
Comparative example 1
Uniformly mixing 4.5g of glucose and 2g of silicon with the particle size of 470nm, adding 50mL of deionized water, ultrasonically dispersing and mixing for 10min, heating from room temperature to 180 ℃ at the heating rate of 10 ℃/min, carrying out heat preservation hydrothermal reaction for 6h, cooling to room temperature, carrying out solid-liquid separation, sequentially washing the obtained solid product with deionized water, washing with absolute ethyl alcohol, and drying at 80 ℃ to constant weight to obtain the silicon-carbon composite material (marked as cys 0) with the particle size of 600-900 nm, wherein the thickness of the carbon polymer layer is 100-400 nm.
Fig. 1 is an SEM image of composite materials prepared in example 1 and comparative example 1, wherein (a) and (b) are example 1 and (c) and (d) are comparative example 1. As can be seen from FIG. 1, the nitrogen-sulfur doped carbon polymer layer in the two composite materials wraps the submicron silicon to form spherical particles. But the pH adjustment is carried out by adding concentrated sulfuric acid, so that the dehydration condensation reaction among different hydroxyl groups is promoted, the combination of silicon and a carbon source is facilitated, and a nitrogen sulfur source is added for doping, so that the diameter of cysS is larger than that of cys0.
Fig. 2 is an XRD pattern of the composite materials prepared in example 1 and comparative example 1, and fig. 3 is an infrared spectrum of the composite materials prepared in example 1 and comparative example 1. As can be seen from fig. 2 to 3, characteristic peaks of Si-C bond, S-C bond, and C-N bond are present in the composite materials prepared in example 1 and comparative example 1, indicating that chemical bonding between Si and C successfully occurred, and nitrogen and sulfur were successfully doped into the carbon polymer layer.
Example 4
(1) Mixing the cysS prepared in example 1 with conductive carbon black and polyacrylic acid in a mass ratio of 6.
And in a glove box filled with argon, taking a carbonate mixture as an electrolyte, taking a lithium ion battery cathode as a negative electrode, taking a metal lithium sheet as a counter electrode, taking Celgard2500 as a diaphragm, mounting the button-type half cell, and standing for 24h to obtain the button-type half cell with the specification of CR2032, wherein the electrolyte is a mixture of ethylene carbonate, dimethyl carbonate, diethyl carbonate and vinylene carbonate, and the concentration of the vinylene carbonate in the electrolyte is 2.0wt%.
Comparative example 2
A negative electrode for a lithium ion battery and a coin-type half cell were manufactured in the same manner as in example 4, except that cysS was replaced with cys0.
Test example 1
(1) Constant current charge and discharge performance test
The constant-current charge and discharge performance tests are carried out on the two button-type half batteries prepared in the embodiment 4 and the comparative example 2, wherein the test voltage range is 0.01-1.2V, the current density is 0.1C (420 mA/g), the test result is shown in fig. 4, as can be seen from fig. 4, the discharge specific capacity of the first circle of cys0 is 1517.1mAh/g, the coulombic efficiency is 77.67%, after 135 circles of circulation, the discharge specific capacity is 793.8mAh/g, and the capacity retention rate is 59.64%; the first circle of the cysS has specific discharge capacity of 5138.9mAh/g and coulomb effect of 82.43%, when the current density is increased to 0.1C (420 mA/g), the specific discharge capacity is 4021.1mAh/g, the coulomb efficiency is improved to 97.80%, after the current density is subjected to charge and discharge for 135 circles continuously, the specific discharge capacity is 2952.6mAh/g, and the capacity retention rate can be observed to be 73.43%, which indicates that the capacity is remarkably low. The nitrogen-sulfur-doped silicon-carbon composite material prepared by the invention has excellent constant current charge and discharge performance, because the nitrogen-sulfur double doping is realized after the concentrated sulfuric acid is added in the embodiment 1, and the constant current charge and discharge performance of the nitrogen-sulfur-doped silicon-carbon composite material is far superior to that of an undoped silicon-carbon composite material.
(2) Rate capability test
The button-type half cells prepared in example 4 and comparative example 2 were subjected to rate performance tests at different current densities with current density gradients of 0.1C, 0.2C, 0.4C, 0.6C, 0.8C, 1.0C, 0.1C, respectively. The test results are shown in table 1 and fig. 5.
Figure BDA0003231082070000091
As can be seen from fig. 5 and table 1, the stability of the rate performance of the nitrogen-sulfur doped silicon-carbon composite material is significantly better than that of the undoped silicon-carbon composite material due to the nitrogen-sulfur double doping during the charging and discharging at different current densities.
(3) AC impedance testing
The ac impedance test was performed on the button-type half cells prepared in example 4 and comparative example 2 in the frequency range of 0.01 to 100kHz and the amplitude of 5mV, and the test results are shown in fig. 6. As can be seen from fig. 6, the impedance radius of the button-type half cell prepared from the nitrogen-sulfur-doped silicon-carbon composite material is smaller than that of the undoped silicon-carbon composite material half cell, indicating that the composite material has better conductivity after being doped with nitrogen and sulfur.
The nitrogen-sulfur-doped silicon-carbon composite materials obtained in the embodiments 2 to 3 are used for preparing a button-type half cell according to the method in the embodiment 1, and then electrochemical tests are carried out according to the test examples (1) to (3), and the test results are similar to those of the nitrogen-sulfur-doped silicon-carbon composite material prepared in the embodiment 1, and the nitrogen-sulfur-doped silicon-carbon composite material has good electrochemical cycle stability, rate capability and conductivity.
In conclusion, the nitrogen-sulfur-doped silicon-carbon composite material prepared by the invention has the advantages of wide raw material source, low price, adoption of one-step hydrothermal reaction, no need of secondary high-temperature carbonization treatment, simple and convenient operation, low cost, low energy consumption and low pollution, and has the potential of industrial production; the overall conductivity of the prepared nitrogen-sulfur doped silicon-carbon composite material is improved, and the defect of low silicon conductivity is effectively overcome; meanwhile, the silicon-based negative electrode shows poor cycling stability and rapid performance attenuation due to the huge volume change problem in the charging and discharging processes, and the nitrogen-sulfur-doped silicon-carbon composite material prepared by the invention shows excellent cycling stability and good rapid charging and discharging capacity, which shows that the nitrogen-sulfur-doped silicon-carbon composite material provided by the invention relieves the volume expansion problem of silicon to a certain extent.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A nitrogen-sulfur doped silicon-carbon composite material comprises submicron silicon and a nitrogen-sulfur doped carbon polymer layer coated on the surface of the submicron silicon;
the nitrogen-sulfur doped carbon polymer layer is obtained by polymerizing a carbon source and a nitrogen-sulfur source;
the preparation method of the nitrogen-sulfur doped silicon-carbon composite material comprises the following steps:
mixing a carbon source, a nitrogen and sulfur source, submicron silicon and water, adjusting the pH value to 1-3, and carrying out hydrothermal reaction to obtain the nitrogen and sulfur doped silicon-carbon composite material.
2. The nitrogen-sulfur-doped silicon-carbon composite material according to claim 1, wherein the particle size of the nitrogen-sulfur-doped silicon-carbon composite material is 1-10 μm.
3. The nitrogen-sulfur doped silicon-carbon composite material according to claim 1 or 2, wherein the carbon source comprises one or more of alkane compounds, phenyl compounds, glucose, starch and cellulose;
the nitrogen-sulfur source is nitrogen-sulfur-containing amino acid.
4. The nitrogen sulfur doped silicon carbon composite material according to claim 1 or 2, wherein the thickness of the nitrogen sulfur doped carbon polymer layer is 0.5 to 9.5 μm.
5. A method for preparing the nitrogen-sulfur doped silicon-carbon composite material according to any one of claims 1 to 4, comprising the following steps:
mixing a carbon source, a nitrogen and sulfur source, submicron silicon and water, adjusting the pH value to 1-3, and carrying out hydrothermal reaction to obtain the nitrogen and sulfur doped silicon-carbon composite material.
6. The method according to claim 5, wherein the mass ratio of nitrogen in the carbon source, the submicron silicon, and the nitrogen-sulfur source to sulfur in the nitrogen-sulfur source is 1: (0.1-3): (0.01-0.15): (0.01-0.20).
7. The preparation method according to claim 5 or 6, characterized in that the temperature of the hydrothermal reaction is 120-210 ℃ and the holding time is 2-16 h.
8. The nitrogen-sulfur-doped silicon-carbon composite material according to any one of claims 1 to 4 or the nitrogen-sulfur-doped silicon-carbon composite material prepared by the preparation method according to any one of claims 5 to 7 is applied to a lithium ion battery.
9. The lithium ion battery negative electrode is characterized by comprising a current collector and an active material layer loaded on the surface of the current collector;
the active material layer comprises the nitrogen-sulfur-doped silicon-carbon composite material as described in any one of claims 1 to 4 or the nitrogen-sulfur-doped silicon-carbon composite material obtained by the preparation method as described in any one of claims 5 to 7, a conductive agent and a binder.
10. The negative electrode for lithium ion batteries according to claim 9, wherein the thickness of the active material layer is 50 to 300 μm.
CN202110987057.5A 2021-08-26 2021-08-26 Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof Active CN113690420B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110987057.5A CN113690420B (en) 2021-08-26 2021-08-26 Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110987057.5A CN113690420B (en) 2021-08-26 2021-08-26 Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof

Publications (2)

Publication Number Publication Date
CN113690420A CN113690420A (en) 2021-11-23
CN113690420B true CN113690420B (en) 2023-03-03

Family

ID=78582833

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110987057.5A Active CN113690420B (en) 2021-08-26 2021-08-26 Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN113690420B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024050714A1 (en) * 2022-09-07 2024-03-14 宁德新能源科技有限公司 Negative electrode sheet, electrochemical device, and electronic device
CN116885144B (en) * 2023-08-21 2024-04-16 深圳市明盛新能源科技有限公司 Silicon-carbon composite material for lithium battery cathode material and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103618071A (en) * 2013-11-14 2014-03-05 中国科学院广州能源研究所 Carbon-silicon composite negative electrode material of lithium ion battery and preparation method thereof
CN105932234A (en) * 2016-05-05 2016-09-07 华东师范大学 Doped porous carbon spheres used for negative electrode material of sodium ion battery and preparation method for doped porous carbon spheres
CN110176592A (en) * 2019-06-03 2019-08-27 哈尔滨工业大学 A kind of preparation method and applications of doped carbon/silicon composite
CN110890551A (en) * 2019-12-02 2020-03-17 一汽解放汽车有限公司 Coated catalyst, preparation method thereof and application thereof in fuel cell
CN112838197A (en) * 2019-11-25 2021-05-25 华为技术有限公司 Negative electrode material, preparation method thereof, battery and terminal

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107302082A (en) * 2016-04-15 2017-10-27 华为技术有限公司 Silicium cathode material and preparation method thereof, cathode pole piece and lithium ion battery

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103618071A (en) * 2013-11-14 2014-03-05 中国科学院广州能源研究所 Carbon-silicon composite negative electrode material of lithium ion battery and preparation method thereof
CN105932234A (en) * 2016-05-05 2016-09-07 华东师范大学 Doped porous carbon spheres used for negative electrode material of sodium ion battery and preparation method for doped porous carbon spheres
CN110176592A (en) * 2019-06-03 2019-08-27 哈尔滨工业大学 A kind of preparation method and applications of doped carbon/silicon composite
CN112838197A (en) * 2019-11-25 2021-05-25 华为技术有限公司 Negative electrode material, preparation method thereof, battery and terminal
CN110890551A (en) * 2019-12-02 2020-03-17 一汽解放汽车有限公司 Coated catalyst, preparation method thereof and application thereof in fuel cell

Also Published As

Publication number Publication date
CN113690420A (en) 2021-11-23

Similar Documents

Publication Publication Date Title
US9437870B2 (en) Nano-silicon composite lithium ion battery anode material coated with poly (3,4-ethylenedioxythiophene) as carbon source and preparation method thereof
CN108011105B (en) Carbon nanosheet material, preparation thereof and application thereof in sodium-ion battery
CN107170965B (en) Silicon-carbon composite material and preparation method and application thereof
CN111180714B (en) Carbon/molybdenum dioxide/silicon/carbon composite material, battery cathode comprising same and lithium ion battery
CN111146427A (en) Method for preparing hollow core-shell structure nano silicon-carbon composite material by using polyaniline as carbon source and secondary battery using material
CN113690420B (en) Nitrogen-sulfur doped silicon-carbon composite material and preparation method and application thereof
CN112110448A (en) Nitrogen-doped carbon and nano-silicon composite anode material and preparation method thereof
WO2023173772A1 (en) Preparation method for and use of hard carbon negative electrode material
CN113889594A (en) Preparation method of boron-doped lithium lanthanum zirconate-coated graphite composite material
CN111777065A (en) Graphite modified material for lithium ion battery and preparation method thereof
CN113871209B (en) Carbon-coated graphene-ferric oxide composite electrode material and preparation method and application thereof
CN103413918A (en) Synthetic method for cathode material lithium cobaltous phosphate used for lithium ion batteries
CN113772718A (en) SnS-SnS2@ GO heterostructure composite material and preparation method and application thereof
CN113921812B (en) Ultra-high power density sodium ion battery and preparation method thereof
CN114105149B (en) Carbon-coated nitrogen-phosphorus double-doped silicon oxide composite material, preparation method thereof and application thereof in lithium ion battery
CN115275168A (en) High-rate lithium ion battery negative electrode material and preparation method thereof
CN111261866A (en) Preparation method of ZnO/C nano composite microsphere material with capsule structure
CN110120506A (en) A kind of preparation method of graphite silicon nanocomposite
CN113571684B (en) Aluminum-carbon double-coated natural graphite negative electrode material for lithium ion battery and preparation method thereof
CN111261857B (en) FePS for sodium ion battery3/NC composite negative electrode material, preparation method thereof and sodium ion battery
CN115050944B (en) Composite material with three-dimensional nano flower structure and preparation method and application thereof
CN117374262B (en) Endogenous heterojunction anode material, preparation method thereof, negative electrode and lithium ion battery
CN111987298B (en) Method for compounding lithium battery silicon carbon by using homogenizer and lithium battery silicon carbon cathode
CN110364706B (en) Antimony oxide-based negative electrode material with high reversible capacity and preparation method thereof
CN110120507B (en) Graphene-modified heterogeneous composite material and preparation method 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