CN116387484A - Preparation method of graphene composite material, graphene composite material and application of graphene composite material - Google Patents

Preparation method of graphene composite material, graphene composite material and application of graphene composite material Download PDF

Info

Publication number
CN116387484A
CN116387484A CN202310364408.6A CN202310364408A CN116387484A CN 116387484 A CN116387484 A CN 116387484A CN 202310364408 A CN202310364408 A CN 202310364408A CN 116387484 A CN116387484 A CN 116387484A
Authority
CN
China
Prior art keywords
graphene
composite material
silicon
preparation
drying
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.)
Pending
Application number
CN202310364408.6A
Other languages
Chinese (zh)
Inventor
张鑫
文钟强
袁强
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.)
Hunan Jinyang Alkene Carbon New Material Co ltd
Original Assignee
Hunan Jinyang Alkene Carbon New Material Co ltd
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 Hunan Jinyang Alkene Carbon New Material Co ltd filed Critical Hunan Jinyang Alkene Carbon New Material Co ltd
Priority to CN202310364408.6A priority Critical patent/CN116387484A/en
Publication of CN116387484A publication Critical patent/CN116387484A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/362Composites
    • H01M4/366Composites as layered products
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00Carbon; Compounds thereof
    • C01B32/15Nano-sized carbon materials
    • C01B32/182Graphene
    • C01B32/184Preparation
    • C01B32/19Preparation by exfoliation
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00Silicon; Compounds thereof
    • C01B33/113Silicon oxides; Hydrates thereof
    • C01B33/12Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/18Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/38Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386Silicon or alloys based on silicon
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/58Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M2004/021Physical characteristics, e.g. porosity, surface area
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M2004/026Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027Negative electrodes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Abstract

The invention discloses a preparation method of a graphene composite material, the graphene composite material and application thereof, and the preparation method of the graphene composite material comprises the following steps: s1, mixing an aqueous solution of graphene oxide, an organic solvent dispersion liquid of silicon powder and a surfactant according to a mass ratio of 2-5:2-5:1, and adding NaBH (sodium silicate-alumina) 4 The reaction is carried out by the reduction,obtaining graphene/silica gel after hydrothermal reaction; s2, drying the graphene/silicon gel obtained in the step S1, and performing freeze drying and heat treatment to obtain a graphene/silicon compound; s3, mixing the graphene/silicon compound obtained in the step S2 with organic acid and aniline monomer according to a mass ratio of 1.5-3: mixing at a ratio of 1.5-3:1, adding an initiator to perform polymerization reaction, and drying in vacuum to obtain the final product. The graphene composite material has the advantages of good conductivity, good cycle performance, high specific capacity, good multiplying power performance and the like, and has a good application prospect in the field of lithium battery preparation.

Description

Preparation method of graphene composite material, graphene composite material and application of graphene composite material
Technical Field
The invention relates to the technical field of batteries, in particular to a preparation method of a graphene composite material, the graphene composite material and application thereof.
Background
The lithium ion battery has the advantages of large specific capacity, high working voltage, good safety, small pollution and the like, and is widely applied to portable electronic equipment, electric automobiles and energy storage equipment in the modern society. However, as the power of the device increases, the capacity of the conventional lithium ion battery cannot meet the daily requirement, and a battery with high capacity becomes a hot spot for research. The negative electrode material is used as a storage main body of lithium ions in the charging and discharging process, and is used for controlling the intercalation and deintercalation of the lithium ions in the working process of the battery, so that the negative electrode material is a key for improving the parameters of the capacity, the cycle performance, the charging and discharging performance and the like of the lithium ion battery. The theoretical specific capacity of the current commercial anode material-graphite is 372mAh/g, so that the improvement of the battery capacity is greatly limited, and the requirement of the market on high energy density is gradually not met. Therefore, development of a novel anode material having a high specific capacity is urgent.
The theoretical capacity of the silicon material can reach 4200mAh/g, but when the silicon material is used as the negative electrode material of the lithium ion battery, the volume change is large and reaches 300% in the adsorption and desorption processes of lithium ions, so that the silicon negative electrode is cracked, the charge and discharge cycle performance is extremely poor, and the application is difficult to realize.
At present, related technologies are used for preparing composite materials from silicon and graphene and preparing high-capacity graphene anode materials, but the long-term charge and discharge performance of the graphene anode materials is still poor.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a preparation method of the graphene composite material, the graphene composite material and application thereof, and the graphene composite material has the advantages of good conductivity, good cycle performance, high specific capacity, good rate capability and the like, and has a good application prospect in the field of lithium battery preparation.
In a first aspect of the present invention, a method for preparing a graphene composite material is provided, including the steps of:
s1, mixing an aqueous solution of graphene oxide, an organic solvent dispersion liquid of silicon powder and a surfactant according to a mass ratio of 2-5:2-5:1, and adding NaBH (sodium silicate-alumina) 4 Reducing, and performing hydrothermal reaction to obtain graphene/silica gel;
s2, drying the graphene/silicon gel obtained in the step S1, and performing freeze drying and heat treatment to obtain a graphene/silicon compound;
s3, mixing the graphene/silicon compound obtained in the step S2 with organic acid and aniline monomer according to a mass ratio of 1.5-3: mixing at a ratio of 1.5-3:1, adding an initiator to perform polymerization reaction, and drying in vacuum to obtain the final product.
According to the invention, the graphene oxide is dispersed by adopting the aqueous solution, and the silicon powder is dispersed by adopting the organic solvent, so that the obtained aqueous solution of the graphene oxide and the organic solvent dispersion of the silicon powder are mixed more uniformly, and the agglomeration phenomenon is avoided. After the organic solvent is dried, graphene/silica gel with multiple pores and increased specific surface area can be formed, and after freeze drying, the structure of the graphene/silica gel is solidified, and the pores of the graphene/silica gel are further increased. The porous graphene/silicon composite prepared by the method has the advantages that the bonding strength of silicon and graphene is improved, the volume expansion of silicon in the charging and discharging process can be effectively buffered, and the cycle performance of silicon is improved. In addition, the existence of pore channels in the graphene/silicon composite can increase the reaction rate of lithium intercalation, thereby being beneficial to improving the rate capability of the composite.
According to the invention, polyaniline is further used for coating the prepared graphene/silicon composite, and in-situ coating of polyaniline can not only prevent side reaction of the graphene/silicon composite and electrolyte, but also further relieve volume expansion of silicon in the lithium intercalation and deintercalation process, so that the graphene composite material prepared by the method has good cycle performance and rate capability.
According to some embodiments of the invention, the temperature of the hydrothermal reaction is 120 ℃ to 180 ℃.
According to some embodiments of the invention, the hydrothermal reaction time is 4-10 hours.
According to some embodiments of the invention, the mass ratio of the aqueous solution of graphene oxide, the organic solvent dispersion of silicon powder and the surfactant is 3-5:2-3:1.
According to some embodiments of the invention, the graphene oxide aqueous solution has a mass fraction of 50% -80%.
According to some embodiments of the invention, the graphene oxide is prepared from modified hummers.
According to some embodiments of the invention, the modified hummers method comprises the steps of:
mixing concentrated sulfuric acid, graphite powder, potassium persulfate and phosphorus pentoxide, adding potassium permanganate, reacting for 1-4 h at 15-25 ℃, then heating to 40-50 ℃ for continuous reaction for 1-4 h, adding deionized water and hydrogen peroxide solution into the reaction system, reacting for 1-4 h at 90-100 ℃, carrying out solid-liquid separation, and vacuum drying to obtain the product.
Preferably, the mass ratio of the graphite powder to the potassium persulfate to the phosphorus pentoxide is 2-4: 1 to 1.5:1.
Preferably, the mass volume ratio of the graphite powder to the concentrated sulfuric acid is 1mg: 15-30 mL.
Preferably, the mass ratio of the potassium permanganate to the graphite powder is 1-2:1.
Preferably, the volume ratio of deionized water to concentrated sulfuric acid is 1:1.5-2.
Preferably, the volume ratio of the hydrogen peroxide solution to the concentrated sulfuric acid is 1:30-50.
Preferably, the mass concentration of the hydrogen peroxide solution is 20% -30%.
The functionalized graphene prepared by the method has higher oxidation degree, enhanced dispersion performance in aqueous solution, reduced self agglomeration phenomenon, more favorable combination with silicon powder, and contribution to forming graphene/silica gel with more uniform pores, thereby increasing the specific surface area of the graphene/silica gel.
According to some embodiments of the invention, the mass fraction of the organic solvent dispersion of the silicon powder is 40% -80%.
According to some embodiments of the invention, the organic solvent comprises at least one of ethanol, ethylene glycol, glycerol.
According to some embodiments of the invention, the silicon powder has a particle size of 200-300 nm.
The agglomeration phenomenon of the silicon powder is serious if the particle size of the silicon powder is too small; on the contrary, if the grain diameter of the silicon powder is too large, sedimentation is easy to occur, and the silicon powder cannot be uniformly dispersed in an organic solvent.
According to some embodiments of the invention, the silicon powder is Siemens-made polycrystalline silicon.
According to some embodiments of the invention, the surfactant is selected from at least one of cetyltrimethylammonium bromide, sodium secondary alkyl sulfonate, sodium fatty alcohol ether sulfate.
According to some embodiments of the invention, the NaBH 4 The mass ratio of the graphene oxide to the graphene oxide is 5-10:1.
According to some embodiments of the invention, in the step S2, the drying temperature is 50-80 ℃ and the drying time is 3-6 hours;
preferably, the freeze-drying temperature is-70 ℃ to-50 ℃ and the freeze-drying time is 24-72 hours;
preferably, the temperature of the heat treatment is 600-1000 ℃, and the time of the heat treatment is 2-6 h.
According to some embodiments of the invention, the organic acid is phytic acid.
When phytic acid is used as the acid medium, the nitrogen (i.e., amine and imine groups) on the aniline chain protonates and crosslinks it, while H + The imide group is protonated to have conductivity. Compared with an inorganic acid system, the phytic acid system has relatively higher conductivity due to relatively higher pH value and slower reaction rate, and the generated polyaniline particles are smaller.
According to some embodiments of the invention, the molar ratio of the initiator to the aniline monomer is 1-1.5:1.
According to some embodiments of the invention, the initiator is ammonium persulfate.
According to some embodiments of the invention, the polymerization reaction temperature is-4 ℃ to 4 ℃.
According to some embodiments of the invention, the polymerization time is 2 to 6 hours.
In a second aspect of the present invention, a graphene composite material is provided, and the graphene composite material is prepared by the preparation method.
In a third aspect of the present invention, a lithium ion battery is provided, in which the negative electrode includes the graphene composite material described above.
The beneficial effects are that:
according to the graphene composite material disclosed by the invention, graphene, silicon powder and a surfactant are cooperatively used to form a pore structure, and the high conductivity and the large mechanical strength of the graphene are utilized to reduce the expansion rate of the silicon material in the charge and discharge process, so that the volume change of the composite material can be effectively controlled, and the dispersion of the surfactant is promoted to prevent the agglomeration phenomenon. The graphene, the silicon powder and the surfactant are uniformly mixed by adopting a hydrothermal method, the materials have stronger binding force, and the pores of the material are increased while the material structure is maintained by adopting a freeze-drying method, so that the volume expansion of silicon can be contained, the specific surface area of the graphene composite material is improved, and the cycle performance of the material is improved.
The graphene composite material is used for a lithium ion battery cathode, is charged and discharged at 100mAh/g, and after 100 times of circulation, the specific capacity is still kept above 1350mAh/g, so that the graphene composite material is expected to be used in a large scale.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Detailed Description
The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.
The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
Example 1
S1, adding 40mg of graphite powder and 20mg of potassium persulfate and 20mg of phosphorus pentoxide into 0.8L of concentrated sulfuric acid, stirring for 4 hours, slowly adding 80mg of potassium permanganate powder at room temperature, keeping the temperature of the whole system at about 20 ℃ in the process, stirring for 2 hours, heating to 45 ℃, preserving heat for 2 hours, dropwise adding 0.5L of deionized water into the obtained mixed solution, controlling the temperature at 95 ℃, dropwise adding 20mL of hydrogen peroxide solution with the mass fraction of 30%, stirring for 3 hours to be uniform, centrifugally filtering, washing to be neutral by deionized water, and vacuum drying to obtain powdery graphene oxide;
s2, adding 50mg of graphene oxide into 20mL of water, and performing ultrasonic dispersion for 20min at room temperature to obtain a graphene oxide solution;
s3, adding Siemens polysilicon into 5M hydrogen fluoride solution, ultrasonically cleaning for 10min, centrifugally filtering, controlling the grain size range to be 200-300 nm, taking 50mg of Siemens polysilicon after cleaning, adding the Siemens polysilicon into a mixed solution consisting of 10mL of ethanol and 10mL of ethylene glycol, uniformly dispersing, and preparing silicon dispersion liquid;
s4, according to the mass ratio of 7:5:2 mixing graphene oxide solution, silicon powder dispersion liquid and hexadecyl trimethyl ammonium bromide, performing ultrasonic reaction for 4 hours, and then adding NaBH 4 Reduction (NaBH) 4 The mass ratio of the graphene oxide to the graphene oxide is 7.5:1), and the obtained mixed solution is placed in a reaction kettle and subjected to hydrothermal reaction at 150 ℃ for 8 hours; drying at normal pressure and 60 ℃ for 5 hours, freeze-drying at-60 ℃ for 48 hours, and finally annealing at 800 ℃ for 4 hours under argon atmosphere to obtain the porous graphene/silicon composite material;
s5, dispersing 80mg of the obtained porous graphene/silicon composite material in 100 mu L of phytic acid solution (the content is 50%, a small amount of surfactant is added according to requirements), adding 30 mu L of aniline monomer, magnetically stirring for 1h under the ice water bath condition, then dropwise adding ammonium persulfate initiator (the molar ratio of ammonium persulfate to aniline monomer is 1:1), and continuously stirring for 4h. And washing to remove the phytic acid and byproducts remained in the reaction, and vacuum drying to obtain the polyaniline-coated porous graphene/silicon composite material.
Example 2
S1, adding 40mg of graphite powder and 20mg of potassium persulfate and 20mg of phosphorus pentoxide into 0.8L of concentrated sulfuric acid, stirring for 4 hours, slowly adding 80mg of potassium permanganate powder at room temperature, keeping the temperature of the whole system at about 25 ℃ in the process, stirring for 1.5 hours, heating to 40 ℃, preserving heat for 1 hour, dropwise adding 0.5L of deionized water into the obtained mixed solution, controlling the temperature to 100 ℃, dropwise adding 20mL of hydrogen peroxide solution with the mass fraction of 30%, stirring for 3 hours to be uniform, centrifugally filtering, washing to be neutral by deionized water, and vacuum drying to obtain powdery graphene oxide;
s2, adding 50mg of graphene oxide into 25mL of water, and performing ultrasonic dispersion for 30min at room temperature to obtain a graphene oxide solution;
s3, adding Siemens polysilicon into 5M hydrogen fluoride solution, ultrasonically cleaning for 10min, centrifugally filtering, controlling the grain size range to be 200-300 nm, taking 50mg of Siemens polysilicon after cleaning, adding the Siemens polysilicon into a mixed solution composed of 15mL of propylene glycol and 10mL of ethylene glycol, uniformly dispersing, and preparing silicon dispersion liquid;
s4, according to the mass ratio of 9:4:2 mixing graphene oxide solution, silicon powder dispersion liquid and hexadecyl trimethyl ammonium bromide, performing ultrasonic reaction for 4 hours, and then adding NaBH 4 Reduction (NaBH) 4 The mass ratio of the graphene oxide to the graphene oxide is 7:1), and the obtained mixed solution is placed in a reaction kettle to be subjected to hydrothermal reaction at 180 ℃ for 6 hours; drying at normal pressure and 50 ℃ for 4 hours, freeze-drying at-60 ℃ for 72 hours, and finally annealing at high temperature of 850 ℃ for 5 hours under argon atmosphere to obtain the porous graphene/silicon composite material;
s5, dispersing 60mg of the obtained porous graphene/silicon composite material in 120 mu L of phytic acid solution (the content is 50%, a small amount of surfactant can be added according to requirements), adding 30 mu L of aniline monomer, magnetically stirring for 1h under the ice water bath condition, then dropwise adding ammonium persulfate initiator (the molar ratio of ammonium persulfate to aniline monomer is 1:1), and continuously stirring for 4h. And washing to remove the phytic acid and byproducts remained in the reaction, and vacuum drying to obtain the polyaniline-coated porous graphene/silicon composite material.
Example 3
S1, adding 50mg of graphite powder and 25mg of potassium persulfate and 20mg of phosphorus pentoxide into 0.75L of concentrated sulfuric acid, stirring for 5 hours, slowly adding 90mg of potassium permanganate powder at room temperature, keeping the temperature of the whole system at about 20 ℃ in the process, stirring for 2 hours, heating to 50 ℃, preserving heat for 1 hour, dropwise adding 0.6L of deionized water into the obtained mixed solution, controlling the temperature at 90 ℃, dropwise adding 30mL of 30% hydrogen peroxide solution, stirring for 3 hours to uniformity, centrifugally filtering, washing to be neutral by deionized water, and drying in vacuum to obtain powdery graphene oxide;
s2, adding 40mg of graphene oxide into 20mL of water, and performing ultrasonic dispersion for 20min at room temperature to obtain a graphene oxide solution;
s3, adding Siemens polysilicon into 5M hydrogen fluoride solution, ultrasonically cleaning for 15min, centrifugally filtering, controlling the grain size range to be 200-300 nm, taking 60mg of Siemens polysilicon after cleaning, adding the Siemens polysilicon into a mixed solution consisting of 10mL of propylene glycol and 20mL of ethanol, uniformly dispersing, and preparing silicon dispersion liquid;
s4, according to the mass ratio of 8:5:2 mixing graphene oxide solution, silicon powder dispersion liquid and hexadecyl trimethyl ammonium bromide, performing ultrasonic reaction for 3 hours, and then adding NaBH 4 Reduction (NaBH) 4 The mass ratio of the graphene oxide to the graphene oxide is 8.5:1), and the obtained mixed solution is placed in a reaction kettle and subjected to hydrothermal reaction for 9 hours at 160 ℃; drying at normal pressure and 55 ℃ for 3 hours, freeze-drying at-60 ℃ for 48 hours, and finally annealing at a high temperature of 800 ℃ for 6 hours under argon atmosphere to obtain the porous graphene/silicon composite material;
s5, dispersing 70mg of the obtained porous graphene/silicon composite material in 200 mu L of phytic acid solution (the content is 50%, a small amount of surfactant can be added according to requirements), adding 40 mu L of aniline monomer, magnetically stirring for 1h under the ice water bath condition, then dropwise adding ammonium persulfate initiator (the molar ratio of ammonium persulfate to aniline monomer is 1.2:1), and continuously stirring for 5h. And washing to remove the phytic acid and byproducts remained in the reaction, and vacuum drying to obtain the polyaniline-coated porous graphene/silicon composite material.
Comparative example 1
Reference to the preparation of example 1, the difference is: step S3 is not included.
Comparative example 2
Reference to the preparation of example 1, the difference is: step S5 is not included.
Comparative example 3
Reference to the preparation of example 1, the difference is: the step S5 comprises the following steps:
1g of the obtained porous graphene/silicon composite material is dispersed in 100 mu L of phytic acid solution (the content is 50%, a small amount of surfactant is added according to the requirement), 30 mu L of aniline monomer is added, magnetic stirring is carried out for 1h under the ice water bath condition, then ammonium persulfate initiator (the molar ratio of ammonium persulfate to aniline monomer is 1:1) is added dropwise, and stirring is continued for 4h. And washing to remove the phytic acid and byproducts remained in the reaction, and vacuum drying to obtain the polyaniline-coated porous graphene/silicon composite material.
Test case
The electrical property test methods of the above examples 1 to 3 and comparative examples 1 to 3 were:
placing the obtained electrode material on a copper foil to prepare a negative electrode plate, and assembling the negative electrode plate and a metal lithium plate into a 2016-type button cell, wherein electrolyte is LiPF (lithium ion battery) of 1mol/L 6 Dissolved in DMC, and the charge-discharge cycle test is carried out at room temperature and current of 100mAh/g for 100 times in the voltage range of 0.02-1.5V.
The results of the electrical property tests of examples 1 to 3 and comparative examples 1 to 3 are shown in Table 1 below.
TABLE 1
Specific capacity for initial discharge (mAh/g) Retention capacity after 100 cycles (mAh/g)
Example 1 2446 1848
Example 2 2016 1410
Example 3 2054 1362
Comparative example 1 574 310
Comparative example 2 1755 709
Comparative example 3 1822 916
From the table, the graphene composite materials prepared in the embodiments 1 to 3 of the invention have high first discharge specific capacity, can effectively reserve capacity, and have good cycle performance.
Compared with example 1, comparative example 1 contains no silicon, only graphene and polyaniline, so that the specific capacity of the first discharge is slightly increased compared with that of the conventional graphite carbon negative electrode material (372 mAh/g).
Compared with example 1, comparative example 2 has no polyaniline coating layer, and the volume expansion phenomenon of silicon in the lithium deintercalation process is serious, so that the prepared graphene composite material has poor cycle performance.
Because polyaniline and graphene are easy to agglomerate, the polymerization ratio of the polyaniline to the graphene is strictly controlled, so that an ideal polyaniline-coated graphene composite structure is achieved. The addition amount of the graphene/silicon composite material in comparative example 3 is greatly increased, and the polyaniline coating effect is poor, resulting in a decrease in the electrical properties of the graphene composite material.
The embodiments of the present invention have been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention. Furthermore, embodiments of the invention and features of the embodiments may be combined with each other without conflict.

Claims (10)

1. The preparation method of the graphene composite material is characterized by comprising the following steps of:
s1, mixing an aqueous solution of graphene oxide, an organic solvent dispersion liquid of silicon powder and a surfactant according to a mass ratio of 2-5:2-5:1, and adding NaBH (sodium silicate-alumina) 4 Reducing, and performing hydrothermal reaction to obtain graphene/silica gel;
s2, drying the graphene/silicon gel obtained in the step S1, and performing freeze drying and heat treatment to obtain a graphene/silicon compound;
s3, mixing the graphene/silicon compound obtained in the step S2 with organic acid and aniline monomer according to a mass ratio of 1.5-3: mixing at a ratio of 1.5-3:1, adding an initiator to perform polymerization reaction, and drying in vacuum to obtain the final product.
2. The preparation method of claim 1, wherein the mass fraction of the aqueous solution of graphene oxide is 50% -80%;
preferably, the preparation method of the graphene oxide comprises the following steps:
mixing concentrated sulfuric acid, graphite powder, potassium persulfate and phosphorus pentoxide, adding potassium permanganate, reacting for 1-4 h at 15-25 ℃, then heating to 40-50 ℃ for continuous reaction for 1-4 h, adding deionized water and hydrogen peroxide solution into the reaction system, reacting for 1-4 h at 90-100 ℃, carrying out solid-liquid separation, and vacuum drying to obtain the product.
3. The preparation method of claim 1, wherein the mass fraction of the organic solvent dispersion of the silicon powder is 40% -80%;
preferably, the grain diameter of the silicon powder is 200-300 nm;
preferably, the silicon powder is Siemens polysilicon.
4. The method of claim 1, wherein the NaBH 4 The mass ratio of the graphene oxide to the graphene oxide is 5-10:1.
5. The method according to claim 1, wherein in the step S2, the freeze-drying temperature is-70 ℃ to-50 ℃;
preferably, the temperature of the heat treatment is 600 ℃ to 1000 ℃.
6. The method of claim 1, wherein the organic acid is phytic acid.
7. The method of claim 1, wherein the molar ratio of the initiator to the aniline monomer is 1 to 1.5:1, a step of;
preferably, the initiator is ammonium persulfate.
8. The method of claim 1, wherein the polymerization reaction temperature is-4 ℃ to 4 ℃;
preferably, the polymerization reaction time is 2 to 6 hours.
9. A graphene composite material, characterized in that it is prepared by the preparation method of any one of claims 1 to 8.
10. A lithium ion battery, wherein the negative electrode comprises the graphene composite material of claim 9.
CN202310364408.6A 2023-04-07 2023-04-07 Preparation method of graphene composite material, graphene composite material and application of graphene composite material Pending CN116387484A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310364408.6A CN116387484A (en) 2023-04-07 2023-04-07 Preparation method of graphene composite material, graphene composite material and application of graphene composite material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310364408.6A CN116387484A (en) 2023-04-07 2023-04-07 Preparation method of graphene composite material, graphene composite material and application of graphene composite material

Publications (1)

Publication Number Publication Date
CN116387484A true CN116387484A (en) 2023-07-04

Family

ID=86974686

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310364408.6A Pending CN116387484A (en) 2023-04-07 2023-04-07 Preparation method of graphene composite material, graphene composite material and application of graphene composite material

Country Status (1)

Country Link
CN (1) CN116387484A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105551828A (en) * 2015-12-11 2016-05-04 郑州大学 Nano titanium dioxide/graphene composite material and preparation method thereof
CN106099061A (en) * 2016-07-14 2016-11-09 中国科学院宁波材料技术与工程研究所 A kind of porous graphene/silicon composite, its preparation method and lithium ion battery
CN109786707A (en) * 2019-01-18 2019-05-21 常州大学 A kind of composite cathode material of lithium ion battery and preparation method thereof
CN111974320A (en) * 2020-08-25 2020-11-24 航天特种材料及工艺技术研究所 High-temperature-resistant elastic graphene aerogel and preparation method thereof
CN115282891A (en) * 2022-08-01 2022-11-04 东莞澳中新材料科技股份有限公司 Preparation method of micron silicon-graphene composite aerogel, electrode and preparation method of electrode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105551828A (en) * 2015-12-11 2016-05-04 郑州大学 Nano titanium dioxide/graphene composite material and preparation method thereof
CN106099061A (en) * 2016-07-14 2016-11-09 中国科学院宁波材料技术与工程研究所 A kind of porous graphene/silicon composite, its preparation method and lithium ion battery
CN109786707A (en) * 2019-01-18 2019-05-21 常州大学 A kind of composite cathode material of lithium ion battery and preparation method thereof
CN111974320A (en) * 2020-08-25 2020-11-24 航天特种材料及工艺技术研究所 High-temperature-resistant elastic graphene aerogel and preparation method thereof
CN115282891A (en) * 2022-08-01 2022-11-04 东莞澳中新材料科技股份有限公司 Preparation method of micron silicon-graphene composite aerogel, electrode and preparation method of electrode

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
CN109301174B (en) Positive electrode material, method for producing same, and lithium secondary battery
CN107026262B (en) High-capacity spherical hard carbon negative electrode material coated with graphene on surface
CN113651304B (en) Organic carbon coated lithium iron phosphate positive electrode material and preparation method thereof
CN108615854B (en) Silicon-based lithium ion battery negative electrode active material and preparation and application thereof
CN110364761B (en) High-energy-density long-circulation lithium iron phosphate battery
CN112271325A (en) Three-dimensional solid-state lithium battery and preparation method thereof
CN114388738B (en) Silicon-based anode material and preparation method and application thereof
CN111193022B (en) Preparation and application of modified ammonium trifluorooxotitanate for lithium ion battery
CN115020685A (en) Lithium iron manganese phosphate positive electrode material and preparation method and application thereof
CN108598417B (en) Conductive carbon black modified silica aerogel sulfur-loaded composite cathode material and preparation method thereof
CN114447321A (en) Positive electrode material, positive plate comprising same and battery
CN112490426B (en) LiFePO4Preparation method of @ C/MXene composite material
CN116387484A (en) Preparation method of graphene composite material, graphene composite material and application of graphene composite material
CN115458793A (en) Low-temperature fast-charging lithium iron phosphate soft-packaged battery cell, manufacturing method and power battery
CN111653787A (en) Silicon-based negative electrode three-dimensional network polyacrylic acid binder and preparation method thereof
CN112271324A (en) High-voltage solid-state lithium battery and preparation method thereof
CN112436146B (en) Lithium battery positive electrode material, preparation method and lithium battery
CN113421993B (en) Preparation and application of chargeable and dischargeable lithium ion battery anode material
CN117117154B (en) Lithium ion battery silicon anode material and preparation method and application thereof
CN116487710B (en) Lithium ion battery and preparation method thereof
CN114361457B (en) Negative electrode piece and secondary battery comprising same
CN114920929B (en) Lithium ion battery anode material, lithium ion battery anode, lithium ion battery and preparation method and application thereof
CN114361410B (en) Quick-charging lithium battery
CN117317201B (en) Carbon-coated graphite negative electrode material and lithium ion battery

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