CN114204000A - Silicon-carbon interlocking flexible self-supporting cathode material, preparation method and application - Google Patents
Silicon-carbon interlocking flexible self-supporting cathode material, preparation method and application Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—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
-
- 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
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- Chemical & Material Sciences (AREA)
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Abstract
A silicon-carbon interlocking flexible self-supporting negative electrode material, a preparation method and application belong to the field of negative electrode materials of lithium ion batteries. Firstly, adding silicon nanoparticles into an organic solvent, and carrying out surface modification on the nanoparticles by using a surfactant to form organic layer-coated silicon nanoparticles with certain steric hindrance; secondly, mixing the precursor solution with an easy-spinning organic polymer to prepare a precursor solution; and finally, solidifying the solution into an organic composite fiber membrane by using an electrostatic spinning method, and obtaining the flexible silicon-carbon composite fiber membrane by using two-step heat treatment of stabilization and carbonization. The preparation process is continuous and simple, the cost is low, the process is simple and controllable, and silicon-carbon anode materials with different properties can be obtained by regulating the ratio of the solution composition to the silicon-carbon; the self-supporting structure can reduce the specific gravity of inert components in the electrode, the added surfactant can effectively eliminate stress concentration when the material is bent, relieve the volume effect of silicon particles in the process of releasing and embedding lithium, and improve the cycle performance and specific capacity of the silicon-carbon negative electrode material.
Description
Technical Field
The invention belongs to the field of lithium ion battery cathode materials, and relates to a silicon-carbon interlocking flexible self-supporting cathode material, a preparation method, application and a preparation method thereof, and application of the silicon-carbon interlocking flexible self-supporting cathode material as a lithium ion battery cathode material in the field of lithium ion batteries.
Background
The lithium ion battery is an energy storage technology with high energy density, small self-discharge, no memory effect, wide working voltage range, long service life and environmental protection. In the modern times, the energy storage device is widely applied to portable electronic equipment, electric automobiles, national defense, power grid energy storage and the like. At present, the growing demand of lithium ion batteries leads the development of battery cathode materials towards higher specific capacity.
At present, the theoretical specific capacity of the traditional lithium ion battery cathode material graphite is 372mAh/g, and the gram capacity of the commercial graphite cathode basically reaches the maximum limit of 350 mAh/g. Silicon can form Li with lithium at normal temperature15Si4The corresponding theoretical specific capacity of the alloy phase is up to 3579mAh/g, which is far higher than that of commercial graphite, and the content of silicon in the earth crust is 26.4%, so that the alloy phase has the advantages of low cost, environmental friendliness, low de-intercalation lithium potential, good safety performance and the like, and therefore, the silicon cathode material is always paid attention to and developed by researchers and is the next generation of lithium ion battery cathode material with the most potential at present.
However, elemental silicon expands up to 300% in volume during charging and discharging, and the intrinsic conductivity of silicon is low; the huge volume expansion effect causes the destruction and pulverization of the material structure, and the material is separated from a current collector, so that the capacity is rapidly attenuated, the cycle performance is deteriorated, and the commercial implementation of the silicon negative electrode is limited.
In existing solutions, carbon coating technology is often used to optimize the electrical conductivity of the silicon material and to mitigate its volume expansion. However, in the coating process, the surface energy of the nano silicon particles is high, so that the nano silicon particles are difficult to uniformly disperse in a carbon substrate, the agglomeration phenomenon is easy to occur, and the huge volume effect causes the collapse of the electrode material structure and even the peeling from the current collector, so that the electrochemical performance is deteriorated; the electrode structure of the traditional coating method contains inert components with large specific gravity, such as a metal current collector, a conductive agent, a binder and the like, so that the internal resistance is increased while the weight of the battery is improved; therefore, integration of the electrodes is a feasible solution to this problem.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a silicon nanoparticle-loaded carbon fiber self-supporting film negative electrode material prepared based on an electrostatic spinning technology, and a surfactant is introduced to modify the surface of silicon nanoparticles, so that the bonding strength between the silicon nanoparticles and one-dimensional carbon fibers, the carbon-coated uniformity and the dispersibility of the silicon nanoparticles in a carbon substrate are improved.
The invention has the value of providing a simple, high-efficiency and low-cost method for preparing the silicon-carbon composite fiber material, the method can realize uniform and continuous production of composite fibers and controllability of a nano structure (fiber diameter, porosity of a fiber film and the like), and the process is simple and convenient.
In order to achieve the purpose, the invention adopts the following technical scheme:
the silicon-carbon interlocking flexible self-supporting negative electrode material comprises a carbon fiber substrate, a carbon shell and a silicon core, wherein the mass ratio of silicon nano active substances is 5-30 wt%, the volume expansion of silicon particles can be effectively buffered due to the existence of the carbon shell, the electric conductivity of the silicon composite material is greatly improved due to the close combination of the carbon fiber substrate and the silicon particles, and the circulation stability of the material is improved.
A preparation method of a silicon-carbon interlocking flexible self-supporting negative electrode material comprises the following steps:
step 1: preparing a precursor solution;
adding silicon nano powder into a precursor solvent to form a nano suspension A, wherein the concentration of the silicon nano powder is 0.005-0.03 g/ml; adding a surfactant into the nano suspension A, and fully modifying the surface of the silicon particles to obtain a silicon particle mixed solution B coated by organic surfactant molecular chain grafting, wherein the concentration of the surfactant is 0.001-0.06 g/ml; and adding the precursor polymer into the mixed solution B, and mechanically stirring for a certain time to fully combine the grafted and coated surfactant group with the polar group of the precursor polymer to prepare a precursor solution C, wherein the concentration of the precursor polymer is 0.05-0.2 g/ml.
The step 1 surfactant includes but is not limited to one or more of alkyl silane coupling agent, amino silane coupling agent, alkenyl silane coupling agent, epoxy alkyl silane coupling agent and alkyl acrylyl oxygen silane coupling agent.
Step 2: electrostatic spinning;
injecting the precursor solution C prepared in the step 1 into an injector at room temperature, performing electrostatic spinning under certain spinning parameters and certain environmental temperature and humidity, and fixing well-dispersed silicon nanoparticles in a polymer fiber substrate to prevent spontaneous agglomeration and electrochemical agglomeration of the silicon nanoparticles in a subsequent lithium desorption reaction; collecting to obtain a silicon-polymer composite fiber film; which comprises a polymer fiber substrate, a polymer shell and a silicon particle inner core.
The spinning parameters in the step 2 are as follows: the glue pushing speed is 0.3-1.5 ml/h, the spinning distance is 8-15 cm, the spinning voltage is 14-24 kV, and the rotating speed of a metal roller collector is 200-600 rpm.
And step 3: heat treatment;
after the silicon-polymer composite fiber film is collected and dried, the silicon-polymer composite fiber film is placed in the air for stabilization heat treatment for a certain time, so that the polymer component is fully cyclized to obtain a heat-resistant trapezoidal structure, and the original structure is still kept in the high-temperature carbonization process. Carbonizing for a certain time in an inert atmosphere to ensure that polymer components (including a polymer fiber substrate, a polymer shell and a surfactant coating layer) are fully carbonized and shrunk, the fiber diameter is reduced, the carbon shell is thinned to improve the conductivity of the material and reduce the diffusion distance between lithium ions and silicon particles in electrolyte; and naturally cooling the inside of the furnace to room temperature, and taking out the furnace to obtain the silicon-carbon interlocking flexible self-supporting negative electrode material.
The surface active agent coating layer is used as a bridge between the silicon nano particles and the precursor polymer, the binding force between the silicon nano particles and the precursor polymer is improved, and a better coating structure is obtained, so that the silicon particles are prevented from falling off and from directly contacting with electrolyte in the subsequent lithium desorption and insertion process, and excellent cycle stability and coulombic efficiency are obtained.
Further, the silicon nano powder in the step 1 has a particle size of D50-10 to 500 nm;
further, the precursor solvent in step 1 includes, but is not limited to, one or more of N, N-dimethylformamide, dimethyl sulfoxide, ethanol, and acetone.
Further, the modification channel in the step 1 includes, but is not limited to, ball milling, ultrasound, and magnetic stirring.
Further, in the step 1, the precursor polymer is one or more of polyacrylonitrile, polyvinylpyrrolidone, polyvinyl alcohol and the like.
Further, the mechanical stirring in the step 1 is ball milling, magnetic stirring and the like; the time is 3-36 h.
Further, in the step 2, the ambient temperature of the room temperature is 20-40 ℃, and the ambient humidity is 20-60%.
Further, in the step 3, a blast drying oven, a muffle furnace or a tube furnace is adopted for the stabilizing heat treatment. The carbonization heat treatment adopts a vacuum tube furnace. The stabilizing heat treatment temperature is 220-300 ℃, and the constant temperature time is 1-8 h; the inert atmosphere of the carbonization heat treatment is argon or nitrogen, the carbonization temperature is 600-1000 ℃, and the constant temperature time is 0.5-8 h.
The application of the silicon-carbon interlocking flexible self-supporting negative electrode material is characterized in that a surfactant is utilized to bind silicon particles and a carbon substrate to form an interlocking structure, so that stress concentration generated when the self-supporting negative electrode material is bent is effectively dispersed and eliminated, excellent flexibility is obtained, macroscopic stress and microscopic stress generated when electrodes are machined and the volume of the silicon particles is changed are adapted, and a solution is provided for a flexible wearable battery; and the tightly combined silicon particle core and the carbon shell, and the silicon particles have good dispersibility in the carbon substrate, so that the electrochemical performance of the cathode material is improved. The electrode plates with different sizes are punched according to the specification of the battery to be used as negative electrodes, the bending rigidity of the electrode plates is lower than 15mN, the electrode plates are applied to the field of lithium ion batteries, the reversible specific capacity of the electrode plates is kept above 660mAh/g after 1000 cycles, and the capacity retention rate is above 90%.
The invention has the following beneficial effects:
1) the invention adopts surfactants with different chemical properties, and the added surfactants can improve the binding force of nano silicon particles and a carbon substrate, form a compact interlocking structure with a graphite carbon domain and an amorphous carbon domain, and effectively eliminate stress concentration when the material is bent, and specifically comprise the following components: one end of the surfactant is combined with the surface of the silicon particles, and the other end of the surfactant is combined with the precursor polymer, so that the nano silicon particles and the carbon fiber substrate have good binding force, and a better coating effect is obtained; the closely combined nano silicon particles, the graphitic carbon domains and the amorphous carbon domains form an interlocking structure, so that stress concentration generated when the composite carbon fiber film is bent can be effectively dispersed and eliminated, and the flexibility of the fiber material is improved. Surfactant molecular chains exist on the surfaces of the silicon particles, so that steric hindrance is provided among the silicon particles, and the agglomeration phenomenon of the silicon particles in the carbon fiber substrate is reduced; thereby inhibiting the volume effect generated in the process of lithium desorption of the silicon material and improving the cycle performance and specific capacity of the material.
2) The invention adopts an integrated electrode design, has no inert components such as a metal current collector, a binder and the like, and improves the integral energy density of the electrode in a weight reduction mode; silicon nano particles are introduced into a carbon fiber substrate by a solution electrostatic spinning method to obtain a flexible composite fiber membrane with good electrochemical and mechanical properties; the structural morphology and the performance of the composite fiber can be accurately controlled by controlling a precursor solution system and the proportion, the spinning voltage, the spinning distance, the spinning speed, the heat treatment process and the like; the preparation process of the cathode material is simple, the cost is low, the preparation process is continuous and controllable, and the industrial application is easy to realize.
Drawings
FIG. 1 is a bending view of a punched self-supporting anode material prepared in example 1 of the present invention.
Fig. 2 is an SEM image of the self-supporting anode material prepared in example 1 of the present invention.
Fig. 3 is a cycle efficiency curve of a button half cell prepared in example 1 of the present invention.
FIG. 4 is an SEM image of a self-supporting anode material prepared in comparative example 1 of the present invention.
Fig. 5 is a cycle efficiency curve of the button half cell prepared in comparative example 1 of the present invention.
Detailed Description
For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the purpose of facilitating understanding of the present invention and should not be construed as specifically limiting the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The reagents or instruments used are not indicated by the manufacturer, and are conventional products available commercially.
The self-supporting structure can greatly reduce the specific gravity of inert components in the electrode, the bonding force between the nano silicon particles and the carbon substrate can be improved by adding the surfactant, a compact interlocking structure is formed between the nano silicon particles and the carbon substrate, and the graphite carbon domain and the amorphous carbon domain, so that the stress concentration of the material during bending is effectively eliminated; the dispersibility of the silicon nano particles in the carbon substrate is improved, the volume effect of the silicon particles in the process of lithium intercalation and deintercalation is effectively relieved, and therefore the cycle performance and the specific capacity of the silicon-carbon negative electrode material are improved. The specific embodiment is as follows:
example 1
(1) Preparation of precursor solution
Putting 10mL of N-N dimethylformamide into a beaker, adding 0.1g of silicon nanoparticles and 0.1g of KH540, and ultrasonically stirring for 30 min; adding 1g of polyacrylonitrile, and stirring for 12 hours at normal temperature to form a uniform colloidal solution.
(2) Electrostatic spinning:
10mL of the precursor solution is extracted by an injector, the glue pushing speed is 0.3mL/h, the spinning voltage is 24kV, the distance between a needle head and a collector is adjusted to be 15cm, and the rotating speed of the collector is 200 rpm.
(3) And (3) heat treatment:
collecting spinning products, placing the spinning products in a tube furnace, heating the spinning products to 280 ℃ at the speed of 2 ℃/min under the air, and keeping the temperature for 2 hours; then heating to 1000 ℃ at the heating rate of 5 ℃/min under the argon atmosphere, and keeping the temperature for 1 h; and cooling to room temperature to obtain the silicon-carbon fiber composite self-supporting negative electrode material.
The prepared silicon-carbon fiber composite self-supporting negative electrode material is directly usedPunching into 14mm round pieces, weighing, and filling into an argon glove box to prepare a CR2025 button type half cell; wherein the electrolyte is 1mol/L LiPF6The solvent is a mixture of 1: 1, a mixed solvent of polyethylene carbonate (EC) and Diethyl Carbonate (DC), and fluoroethylene carbonate (FEC) accounting for 10% of volume as an electrolyte additive; polypropylene (PP) is used as a diaphragm, and a lithium metal sheet is used as a counter electrode.
Fig. 1 is a bending diagram of the composite fiber membrane prepared by the invention after punching, which shows good flexibility, and stress concentration in material bending can be effectively dispersed and eliminated due to the interlocking structure of the nano silicon particles and the carbon substrate.
FIG. 2 is a scanning electron microscope image of the silicon-carbon fiber self-supporting cathode material prepared by the present invention, which shows that silicon nanoparticles are uniformly loaded on a one-dimensional carbon fiber substrate and there is almost no large-area agglomeration phenomenon.
FIG. 3 is a cycle performance diagram obtained when the silicon-carbon fiber self-supporting negative electrode material prepared by the invention is used for testing a lithium ion half cell. Under room temperature, in the voltage range of 0.01-3V, after the first 20 times of circulation and small current formation (not shown in the figure), the voltage is 1A g-1The current density is tested by charging and discharging, the first reversible specific capacity is 756mAh/g, after 1000 cycles, the reversible specific capacity is maintained at 690mAh/g, and the capacity retention rate is 91.2%.
Comparative example 1
(1) Preparation of precursor solution
Putting 10mL of N-N dimethylformamide into a beaker, adding 0.1g of silicon nanoparticles, and ultrasonically stirring for 30 min; adding 1g of polyacrylonitrile, and stirring for 12 hours at normal temperature to form a uniform colloidal solution.
(2) Electrostatic spinning:
10mL of the precursor solution is extracted by an injector, the glue pushing speed is 0.3mL/h, the spinning voltage is 24kV, the distance between a needle head and a collector is adjusted to be 15cm, and the rotating speed of the collector is 200 rpm.
(3) And (3) heat treatment:
collecting spinning products, placing the spinning products in a tube furnace, heating the spinning products to 280 ℃ at the speed of 2 ℃/min under the air, and keeping the temperature for 2 hours; then heating to 1000 ℃ at the heating rate of 5 ℃/min under the argon atmosphere, and keeping the temperature for 1 h; and cooling to room temperature to obtain the silicon-carbon fiber composite self-supporting negative electrode material.
Experimental cells were fabricated and tested in the same manner as in example 1.
FIG. 4 is a scanning electron microscope image of the self-supporting anode material of comparative example 1 of the present invention, in which the silicon nanoparticles without surface modification are agglomerated in a large area.
FIG. 5 is a graph of the cycling performance of comparative example 1 self-supporting anode material of the present invention when used in a lithium ion half cell test. At 1A g-1The current density is tested for charge and discharge, the first reversible specific capacity is 674mAh/g, after 150 cycles, the reversible specific capacity is kept at 275mAh/g, and the capacity retention rate is as low as 40.8%.
The silicon nano particles which are not subjected to surface modification have poor dispersibility, poor carbon coating effect and weak binding force with a carbon substrate, so that the self-supporting electrode has poor circulation stability, and structural collapse and specific capacity diving are caused too early.
Example 2
(1) Preparing a precursor solution:
putting 10mL of N-N dimethylformamide into a beaker, adding 0.05g of silicon nanoparticles and 0.01g of KH560, and stirring for 1h at 80 ℃; 0.5g of polyvinylpyrrolidone is added and stirred for 24 hours at normal temperature to form a uniform colloidal solution.
(2) Electrostatic spinning:
10mL of the precursor solution is extracted by an injector, the glue pushing speed is 1.5mL/h, the spinning voltage is 14kV, the distance between a needle head and a collector is adjusted to be 8cm, and the rotating speed of the collector is 600 rpm.
(3) And (3) heat treatment:
collecting spinning products, placing the spinning products in a tube furnace, heating the spinning products to 220 ℃ at the speed of 1 ℃/min under the air, and keeping the temperature for 1.5 h; then heating to 600 ℃ at the heating rate of 3 ℃/min under the argon atmosphere, and keeping the temperature for 6 hours; and cooling to room temperature to obtain the silicon-carbon fiber composite self-supporting negative electrode material.
Experimental cells were fabricated and tested in the same manner as in example 1. At 1A g-1The current density is tested for charging and discharging, the first reversible specific capacity is 723mAh/g, and after 1000 cycles, the reversible specific capacity is kept to 663mAh/g, the capacity retention rate is 91.8%.
Example 3
(1) Preparing a precursor solution:
placing 10mL of absolute ethyl alcohol in a beaker, adding 0.3g of silicon nanoparticles and 0.6g of KH602, and performing ultrasonic dispersion for 30 min; 2g of polyvinylpyrrolidone is added and stirred for 24 hours at normal temperature to form uniform colloidal solution.
(2) Electrostatic spinning:
10mL of the precursor solution is extracted by an injector, the glue pushing speed is 0.8mL/h, the spinning voltage is 17kV, the distance between a needle head and a collector is adjusted to be 10cm, and the rotating speed of the collector is 500 rpm.
(3) And (3) heat treatment:
collecting spinning products, placing the spinning products in a tube furnace, heating the spinning products to 300 ℃ at the speed of 1 ℃/min under the air, and keeping the temperature for 0.5 h; then heating to 750 ℃ at the heating rate of 3 ℃/min under the argon atmosphere, and keeping the temperature for 3 h; and cooling to room temperature to obtain the silicon-carbon fiber composite self-supporting negative electrode material.
Experimental cells were fabricated and tested in the same manner as in example 1. At 1A g-1And the current density is subjected to charge and discharge tests, the first reversible specific capacity is 809mAh/g, after 1000 cycles, the reversible specific capacity is kept at 734mAh/g, and the capacity retention rate is 90.7%.
Example 4
(1) Preparing a precursor solution:
putting 10ml of N-dimethylformamide into a beaker, adding 0.2g of silicon nanoparticles and 0.1g of KH570, and ultrasonically stirring for 60 min; adding 1.5g of polyvinyl alcohol, and stirring for 12 hours at normal temperature to form a uniform colloidal solution.
(2) Electrostatic spinning:
10mL of the precursor solution is extracted by an injector, the glue pushing speed is 1mL/h, the spinning voltage is 15kV, the distance between a needle head and a collector is adjusted to be 12cm, and the rotating speed of the collector is 600 rpm.
(3) And (3) heat treatment:
collecting spinning products, placing the spinning products in a tube furnace, heating the spinning products to 280 ℃ at the speed of 1 ℃/min under the air, and keeping the temperature for 1 h; then heating to 800 ℃ at the heating rate of 3 ℃/min under the argon atmosphere, and keeping the temperature for 2 h; and cooling to room temperature to obtain the silicon-carbon fiber composite self-supporting negative electrode material.
Experimental cells were fabricated and tested in the same manner as in example 1. At 1A g-1And the current density is subjected to charge and discharge tests, the first reversible specific capacity is 742mAh/g, after 1000 cycles, the reversible specific capacity is kept at 670mAh/g, and the capacity retention rate is 90.3%.
The above-mentioned embodiments only express the embodiments of the present invention, but not should be understood as the limitation of the scope of the invention patent, it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the concept of the present invention, and these all fall into the protection scope of the present invention.
Claims (10)
1. A preparation method of a silicon-carbon interlocking flexible self-supporting negative electrode material is characterized by comprising the following steps:
step 1: preparing a precursor solution;
adding silicon nano powder into a precursor solvent to form a nano suspension A, wherein the concentration of the silicon nano powder is 0.005-0.03 g/ml; adding a surfactant into the nano suspension A, and fully modifying the surface of the silicon particles to obtain a silicon particle mixed solution B coated by organic surfactant molecular chain grafting, wherein the concentration of the surfactant is 0.001-0.06 g/ml; adding a precursor polymer into the mixed solution B, and mechanically stirring to obtain a precursor solution C, wherein the concentration of the precursor polymer is 0.05-0.2 g/ml;
the surfactant in the step 1 comprises one or more compounds of an alkyl silane coupling agent, an amino silane coupling agent, an alkenyl silane coupling agent, an epoxy alkyl silane coupling agent and an alkyl acryloyl oxy silane coupling agent;
step 2: electrostatic spinning;
injecting the precursor solution C prepared in the step 1 into an injector at room temperature, performing electrostatic spinning, and fixing well-dispersed silicon nanoparticles in a polymer fiber substrate to prevent spontaneous agglomeration and electrochemical agglomeration of the silicon nanoparticles in a subsequent lithium desorption reaction; finally obtaining the silicon-polymer composite fiber film;
and step 3: heat treatment;
and drying the silicon-polymer composite fiber film, placing the silicon-polymer composite fiber film in the air for stabilizing heat treatment, carbonizing the silicon-polymer composite fiber film in an inert atmosphere, naturally cooling the silicon-polymer composite fiber film in a furnace to room temperature after carbonization treatment, and taking the silicon-polymer composite fiber film out to obtain the silicon-carbon interlocking flexible self-supporting negative electrode material.
2. The preparation method of the silicon-carbon interlocking flexible self-supporting negative electrode material as claimed in claim 1, wherein the spinning parameters in the step 2 are as follows: the glue pushing speed is 0.3-1.5 ml/h, the spinning distance is 8-15 cm, the spinning voltage is 14-24 kV, and the rotating speed of a metal roller collector is 200-600 rpm.
3. The method for preparing the silicon-carbon interlocked flexible self-supporting negative electrode material according to claim 1, wherein the silicon nanopowder obtained in the step 1 has a particle size of D50-10-500 nm.
4. The method for preparing the silicon-carbon interlocked flexible self-supporting negative electrode material according to claim 1, wherein the precursor solvent in the step 1 includes but is not limited to one or more of N, N-dimethylformamide, dimethyl sulfoxide, ethanol or acetone.
5. The preparation method of the silicon-carbon interlocking flexible self-supporting negative electrode material as claimed in claim 1, wherein the precursor polymer in the step 1 is one or more of polyacrylonitrile, polyvinylpyrrolidone, polyvinyl alcohol and the like.
6. The preparation method of the silicon-carbon interlocking flexible self-supporting anode material according to claim 1, wherein the mechanical stirring time in the step 1 is 3-36 h.
7. The preparation method of the silicon-carbon interlocking flexible self-supporting negative electrode material as claimed in claim 1, wherein the ambient temperature of the room temperature in the step 2 is 20-40 ℃, and the ambient humidity is 20-60%.
8. The preparation method of the silicon-carbon interlocking flexible self-supporting negative electrode material according to claim 1, wherein the stabilizing heat treatment temperature in the step 3 is 220-300 ℃, and the constant temperature time is 1-8 h; the inert atmosphere of the carbonization heat treatment is argon or nitrogen, the carbonization temperature is 600-1000 ℃, and the constant temperature time is 0.5-8 h.
9. A silicon-carbon interlocked flexible self-supporting negative electrode material, which is characterized in that the self-supporting negative electrode material is prepared by the preparation method of any one of claims 1 to 8.
10. The application of the silicon-carbon interlocking flexible self-supporting negative electrode material as claimed in claim 9 is characterized in that electrode plates with different sizes are punched according to the specification of a battery to serve as negative electrodes, the negative electrodes are applied to the field of lithium ion batteries, the reversible specific capacity is kept above 660mAh/g after 1000 cycles, and the capacity retention rate is above 90%.
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| CN115148975A (en) * | 2022-07-29 | 2022-10-04 | 合肥综合性国家科学中心能源研究院(安徽省能源实验室) | Silicon oxide/carbon negative electrode material of self-supporting lithium ion battery and preparation method |
| CN116207243A (en) * | 2023-02-22 | 2023-06-02 | 胜华新材料集团股份有限公司 | Fibrous silicon-carbon composite material and preparation method thereof |
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| CN115148975A (en) * | 2022-07-29 | 2022-10-04 | 合肥综合性国家科学中心能源研究院(安徽省能源实验室) | Silicon oxide/carbon negative electrode material of self-supporting lithium ion battery and preparation method |
| CN116207243A (en) * | 2023-02-22 | 2023-06-02 | 胜华新材料集团股份有限公司 | Fibrous silicon-carbon composite material and preparation method thereof |
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