CN115000356A - Silicon electrode and preparation method and application thereof - Google Patents

Silicon electrode and preparation method and application thereof Download PDF

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Publication number
CN115000356A
CN115000356A CN202210693045.6A CN202210693045A CN115000356A CN 115000356 A CN115000356 A CN 115000356A CN 202210693045 A CN202210693045 A CN 202210693045A CN 115000356 A CN115000356 A CN 115000356A
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silicon
lithium
solution
conducting
electrode
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袁帅
苏永祥
施利毅
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Shanghai University (zhejiang Jiaxing) Emerging Industry Research Institute
University of Shanghai for Science and Technology
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Shanghai University (zhejiang Jiaxing) Emerging Industry Research Institute
University of Shanghai for Science and Technology
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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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • 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
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • 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
    • H01M2004/026—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 particularly relates to a silicon electrode and a preparation method and application thereof, belonging to the technical field of lithium batteries, and the method comprises the following steps: mixing an inorganic conductive material with a lithium-conducting polymer solution to obtain a mixed solution; mixing nano silicon and a bonding solution to obtain bonding slurry; mixing the mixed solution and the bonding slurry to obtain electrode slurry; coating the electrode slurry, and then drying to obtain a silicon electrode; the lithium conducting polymer is used for coating the inorganic conducting material to form a lithium conducting framework, the conducting material is tightly connected to the surface of the silicon particles by the lithium conducting polymer, the electric contact separation in the circulation process is prevented, the tight interface formed by the lithium conducting framework and the silicon particles can improve the electron transmission path and the lithium ion diffusion speed on the surface of the silicon particles, and the lithium conducting framework, the lithium conducting framework and the lithium conducting and conducting interface can reduce the impedance of a silicon cathode and improve the lithium ion diffusion speed, so that the problem of poor low-temperature electrochemical performance of the conventional lithium battery is solved.

Description

Silicon electrode and preparation method and application thereof
Technical Field
The invention belongs to the technical field of lithium batteries, and particularly relates to a silicon electrode and a preparation method and application thereof.
Background
The development of all-weather renewable energy systems, electric vehicles and a series of related industries has led to increasing demands for fast charge and discharge performance, low-temperature cycle stability and high energy density of rechargeable Lithium Ion Batteries (LIBs).
Currently, the lithium ion battery cathode which is dominant in the market is graphite with a theoretical capacity of only 372 mAh/g. Besides the lower theoretical capacity, the specific capacity and the cycling stability of the graphite negative electrode at low temperature are also poorer. The theoretical capacity of the silicon negative electrode is 4200mAh/g, the potential of the silicon negative electrode is low relative to Li/Li +, and the silicon negative electrode is abundant in the earth crust and is the most ideal substitute material for the negative electrode of the high-capacity lithium battery.
However, there are many important problems to be solved in the way of commercialization and practical application of silicon anodes. On one hand, the volume change of the silicon negative electrode after circulation exceeds 300%, which brings about the problems of silicon particle breakage, separation, unstable interface of the electrode surface and the like. On the other hand, the silicon negative electrode has poor conductivity and lithium conductivity, so that the lithium ion diffusion kinetic force is poor, and the low-temperature electrochemical performance is seriously influenced.
Disclosure of Invention
The application aims to provide a silicon electrode and a preparation method and application thereof, so as to solve the problem that the low-temperature electrochemical performance of the conventional lithium battery is poor.
The embodiment of the invention provides a preparation method of a silicon electrode, which comprises the following steps:
mixing an inorganic conductive material with a lithium-conducting polymer solution to form a lithium-conducting framework to obtain a mixed solution;
mixing nano silicon and a bonding solution to obtain bonding slurry;
mixing the mixed solution and the bonding slurry to enable the lithium-conductive framework to be connected with the surface of the nano silicon to form a tight interface, so as to obtain electrode slurry;
and coating the electrode slurry, and drying to obtain the silicon electrode.
Optionally, the inorganic conductive material includes at least one of carbon nanotubes, graphene, titanium carbon, and molybdenum disulfide.
Optionally, the lithium-conducting polymer solution is a lithiated Nafion solution.
Optionally, the raw material of the bonding solution includes a conductive polymer and a stretchable self-healing polymer.
Optionally, the conductive polymer is poly 3, 4-ethylenedioxythiophene: polystyrene sulfonate.
Optionally, the self-healing polymer is polyether thiourea.
Optionally, during the mixing of the nano silicon and the bonding solution, the mixing is performed by gradient stirring at a first speed and a second speed.
Optionally, the drying includes low-temperature pre-drying and high-temperature drying.
Based on the same inventive concept, the embodiment of the invention also provides a silicon electrode, and the silicon electrode is prepared by adopting the preparation method of the silicon electrode.
Based on the same inventive concept, embodiments of the present invention also provide a use of a silicon electrode, including applying the silicon electrode as described above to a negative electrode of a lithium battery.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
according to the preparation method of the silicon electrode provided by the embodiment of the invention, the lithium conducting polymer is used for coating the inorganic conducting material to form the lithium conducting framework, the lithium conducting polymer is used for tightly connecting the conducting material on the surface of the silicon particles, so that the electrical contact separation in the circulation process is prevented, the tight interface formed by the lithium conducting framework and the silicon particles can improve the electron transmission path and the lithium ion diffusion speed on the surface of the silicon particles, and the lithium conducting framework, the lithium conducting framework and the lithium conducting and conducting interface can reduce the impedance of a silicon cathode and improve the lithium ion diffusion speed, so that the problem of poor low-temperature electrochemical performance of the conventional lithium battery is solved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart of a method provided by an embodiment of the present invention;
FIG. 2 is an SEM image of a silicon electrode provided in example 1 of the present invention;
FIG. 3 is a graph of the cycle performance at normal and low temperatures for silicon electrodes provided in example 1 of the present invention and comparative example 1;
fig. 4 is a graph of rate performance at normal and low temperatures for cells assembled from silicon electrodes provided in example 1 of the present invention and comparative example 1.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to an exemplary embodiment of the present invention, there is provided a method of manufacturing a silicon electrode, the method including:
s1, mixing an inorganic conductive material with a lithium-conducting polymer solution to obtain a mixed solution;
specifically, in this embodiment, an inorganic conductive material is added into a lithium conducting polymer solution at 60-70 ℃ for 15-30min of ultrasound, the longer the ultrasound time is, the more uniformly the CNTs are dispersed, and then stirred for 9-12 h;
in some embodiments, the inorganic conductive material includes Carbon Nanotubes (CNT), Graphene (GN), titanium carbon (MXene), and molybdenum disulfide (MoS) 2 ) At least one of (1).
Carbon Nanotube (CNT) Graphene (GN), titanium carbon (MXene), molybdenum disulfide MoS 2 Are all common conductive materials with good conductivity.
In some embodiments, the lithium conducting polymer solution is a lithiated Nafion solution. In this embodiment, the lithium-conducting polymer solution is a 1% diluted solution, but in other embodiments, a person skilled in the art can select lithium-conducting polymer solutions with other mass concentrations as needed.
In this embodiment, the mass portion of the inorganic conductive material is 1.0-1.5 parts, and the mass portion of the lithium-conducting polymer solution is 100-150 parts. Generally, the more the inorganic conductive material is, the greater the mechanical strength is, and the more the lithium conductive polymer solution is, the better the lithium conductive property is.
S2, mixing the nano-silicon with the bonding solution to obtain bonding slurry;
specifically, in this embodiment, the conductive polymer and the stretchable self-healing polymer are mixed and stirred at 25 ℃ for 3 to 6 hours to form a mixed solution (the solvent is dimethyl sulfoxide, and the mass fraction of dimethyl sulfoxide is 0.4 to 1.2 parts); adding nano silicon into the mixed solution, and continuously stirring to form mixed slurry; firstly stirring the mixed slurry quickly (the stirring speed is 600-800rmp/min, the stirring time is 1-3h) and then stirring the mixed slurry slowly (the stirring speed is 200-400rmp/min, the stirring time is 1-3 h); forming bonding slurry; fully coating the cross-linked substances of PEDOT and PSS-PETU on the nano silicon to obtain a product of the silicon coated by the PEDOT and PSS-PETU; in general, the longer the stirring time, the more uniform the crosslinking.
In the embodiment, the mass fraction of the conductive polymer is 10-12 parts, the mass fraction of the stretchable self-healing polymer is 8-10 parts, and the mass fraction of the nano silicon is 80-90 parts. Generally, the larger the mass fraction of the conductive polymer, the higher the conductivity, and the larger the mass fraction of the stretchable self-healing polymer, the better the mechanical properties. The more the mass fraction of the nano silicon is, the higher the first area capacity is.
In some embodiments, the raw material of the bonding solution includes a conductive polymer and a stretchable self-healing polymer.
In this embodiment, the conductive polymer is poly 3, 4-ethylenedioxythiophene: the reason why the conductive polymer is adopted in the embodiment is that the material is completely commercialized, is easy to obtain and has good mechanical properties, and it is expected that other conductive polymers can be adopted to replace the conductive polymer (PRDOT: PSS) in other embodiments; the self-healing polymer can be stretched to be polyether thiourea, and specifically, the polyether thiourea can be polyether thiourea TUEG3, polyether thiourea TUEG2 and polyether urea UEG 3. Polyether thiourea may be reacted with PEDOT: PSS can form abundant hydrogen bonds; the silicon negative electrode has good stretchability and high self-healing speed, and is beneficial to relieving silicon particle crushing when being applied to a silicon negative electrode.
The preparation method of the stretchable self-healing polymer comprises the following steps: 4.45g (0.025mol) of 1,1 '-thiocarbonyldiimidazole was charged in a three-necked flask equipped with magnetons, and 12.5ml of an ultra-dry N-Dimethylformamide (DMF) solution was slowly added to the flask, and 1,1' -thiocarbonyldiimidazole was sufficiently dissolved in DMF with magnetic stirring to obtain a yellowish brown transparent solution. Under the protection of high-purity nitrogen, 3.875g (0.0263mol) of 1, 2-bis (2-aminoethoxy) ethane liquid was added to the above mixed solution, and the above mixed solution was continuously stirred at 25 ℃ for 24 hours to obtain a brown turbid solution. 25.0mL of chloroform was weighed into the above cloudy mixture solution. The solution was then poured into 375mL of diethyl ether (Et2O), followed by a turbidity of the Et2O solution with a tan precipitate settling at the bottom of the beaker. The cloudy solution was poured off and chloroform was added to the beaker to dissolve the tan precipitate. Washing with chloroform/methanol solution for three times to obtain polyether thiourea product, placing the product into a polytetrafluoroethylene mold, vacuum drying at 140 deg.C for 12h, cooling, and placing into a drying oven for later use.
Generally, in mixing the nano-silicon and the binding solution, the mixing is performed by a rapid and then slow gradient stirring. The rapid stirring is beneficial to the uniform distribution of the silicon particles, and the slow stirring is beneficial to the coating of the polymer on the surfaces of the silicon particles. Finally, uniform and comprehensive coating can be formed.
S3, mixing the mixed solution with the bonding slurry to obtain electrode slurry;
in this example, the mixture of the mixed solution and the adhesive slurry was mixed by dropwise addition. Specifically, the mixed solution is added into the bonding slurry drop by drop to form electrode slurry, and the electrode slurry is continuously stirred for 4 to 8 hours;
and S4, coating the electrode slurry, and drying to obtain the silicon electrode.
In some embodiments, drying includes low temperature pre-drying and high temperature drying. The low-temperature pre-drying temperature is 60-100 ℃, and the low-temperature pre-drying time is 8-12 h; the high-temperature drying temperature is 160-180 ℃, and the high-temperature drying time is 4-8 h.
In this embodiment, the stirred electrode slurry is uniformly coated on a copper foil, and then pre-dried at a low temperature and dried at a high temperature to obtain a silicon electrode. Specifically, the slurry was coated on a copper current collector by a doctor blade method to obtain a wet silicon negative electrode. And putting the wet silicon cathode into a vacuum oven with the temperature of 60-100 ℃ for pre-drying for 8-12h, and then completely drying in the vacuum oven with the temperature of 160-180 ℃ for 4-8h to finally obtain the silicon cathode.
Taking carbon nanotubes as an example, the whole process is as follows: the carbon nanotube is firstly coated with Li-nafion and then is mixed with PEDOT: the PSS-PETU coated silicon was mixed to finally form an inner flexible PEDOT: and the PSS-PETU and the external rigid Li-nafion @ CNT are used for grading and dissipating the expansion stress of the silicon negative electrode. When the inorganic conductive material is other material, the process is similar to the above process, and so on.
According to another exemplary embodiment of the present invention, there is provided a silicon electrode manufactured using the method of manufacturing a silicon electrode as described above.
According to another exemplary embodiment of the present invention, there is provided a use of a silicon electrode, the use comprising applying a silicon electrode as described above to a negative electrode of a lithium battery.
The silicon electrode of the present application, and the production method and application thereof will be described in detail below with reference to examples, comparative examples, and experimental data.
Example 1
A method of making a silicon electrode, the method comprising:
weighing 0.5g of perfluorosulfonic acid resin (Nafion) particles by using an electronic balance, slowly adding the particles into a hydrothermal reaction kettle, adding 5.59g of water and 4.41g of ethanol (namely the volume ratio of the water to the ethanol is 1: 1) into the reaction kettle, covering the reaction kettle, putting the reaction kettle into a 230 ℃ oven, and heating for 4 hours to uniformly dissolve the Nafion into a mixed solution of the water and the ethanol to prepare a Nafion uniform solution with the mass fraction of 5%. 10g of the homogeneous solution of perfluorosulfonic acid resin (Nafion) was added to a reagent bottle with magnetons. 25.2mg of lithium hydroxide monohydrate (LiOH. H) was added to the reagent bottle 2 O) powder. And (3) carrying out ultrasonic treatment for 10min at normal temperature to fully and uniformly dissolve the solute, and then stirring for 2h at 60 ℃ to obtain a Li-Nafion uniform solution with the mass percent of about 5%. 0.02CNT and 0.8g of 5% Li-Nafion solution are added into a reagent bottle with magnetons in the reagent, so that the mass ratio of CNT to Li-Nafion is 1: 2, then ultrasonic treatment for 30min to make the CNT evenly distributed in the solution. And then placing the reagent bottle containing the mixed solution of the CNT and the Li-Nafion into an oil bath kettle at 60 ℃, stirring magnetons to ensure that the Li-Nafion is fully adsorbed on the CNT, and finally obtaining the Li-Nafion-coated lithium-conducting and CNT network (Li-Nafion @ CNT).
0.91g of a 1.1 wt% highly conductive PEDOT/PSS solution was added to 0.7g of a 1.0 wt% polyether thiourea (PETU) solution, and then 0.003g of dimethyl sulfoxide was added thereto, and the mixture was stirred at 25 ℃ for 3 hours to sufficiently crosslink the mixed solution.
0.08g of nano silicon powder is taken and added into a cross-linked product of PEDOT, PSS and PETU (PEDOT, PSS-PETU), and magnetons are stirred for 4 hours (firstly, the nano silicon is stirred quickly to be mixed evenly, and then, the cross-linked product of the PEDOT, PSS-PETU is fully coated on the nano silicon by stirring slowly), so that a product of the silicon coated by the PEDOT, PSS-PETU is obtained.
Finally, dropwise adding Li-Nafion @ CNT into the product to obtain final negative electrode slurry, wherein the ratio of Si to PEDOT to PSS to PETU to Li-Nafion @ CNT in the negative electrode slurry is 8:1:0.7:0.3, and continuously stirring for 5 hours.
The slurry was coated on a copper current collector by a doctor blade method to obtain a wet silicon negative electrode. And (3) putting the wet silicon cathode into a vacuum oven at 100 ℃ for pre-drying for 12 hours, and then completely drying in the vacuum oven at 180 ℃ for 6 hours to finally obtain the silicon cathode for experiments. The thickness of the experimental silicon negative electrode and the mass loading of the active material were about 10 μm and 0.75mg cm, respectively -2 。
Example 2
A method of making a silicon electrode, the method comprising:
weighing 0.5g of perfluorosulfonic acid resin (Nafion) particles by using an electronic balance, slowly adding the particles into a hydrothermal reaction kettle, adding 5.59g of water and 4.41g of ethanol (namely the volume ratio of the water to the ethanol is 1: 1) into the reaction kettle, covering the reaction kettle, putting the reaction kettle into a 230 ℃ oven, and heating for 4 hours to uniformly dissolve the Nafion into a mixed solution of the water and the ethanol to prepare a Nafion uniform solution with the mass fraction of 5%. 10g of Nafion homogeneous solution was added to a reagent bottle with magnetons. 25.2mg of lithium hydroxide monohydrate (LiOH. H) was added to the reagent bottle 2 O) powder. And (3) carrying out ultrasonic treatment for 10min at normal temperature to fully and uniformly dissolve the solute, and then stirring for 2h at 60 ℃ to obtain a Li-Nafion uniform solution with the mass percentage of about 5%. Adding 0.02GN and 0.8g of 5% Li-Nafion solution into a reagent bottle with magnetons in the reagent, so that the mass ratio of Graphene (GN) to Li-Nafion is 1: 2 followed by sonication for 30min to distribute the GN evenly in the solution. Then placing the reagent bottle containing GN and Li-Nafion mixed solution into an oil bath kettle at 60 ℃, and stirring by magnetons to ensure thatLi-Nafion is fully adsorbed on GN, and finally, a Li-Nafion-coated conductive lithium and conductive GN network (Li-Nafion @ CNT) is obtained.
4.45g (0.025mol) of 1,1 '-thiocarbonyldiimidazole was charged in a three-necked flask equipped with magnetons, and 12.5mL of an ultra-dry solution of DMF was slowly added to the flask, and 1,1' -thiocarbonyldiimidazole was sufficiently dissolved in DMF with magnetic stirring to obtain a yellowish brown transparent solution. Under the protection of high-purity nitrogen, 3.875g (0.0263mol) of 1, 2-bis (2-aminoethoxy) ethane liquid was added to the above mixed solution, and the above mixed solution was continuously stirred at 25 ℃ for 24 hours to obtain a brown turbid solution. 25.0mL of chloroform was weighed into the above cloudy mixture solution. The solution was then poured into 375mL of diethyl ether (Et2O), followed by a turbidity of the Et2O solution with a tan precipitate settling at the bottom of the beaker. The cloudy solution was poured off and chloroform was added to the beaker to dissolve the tan precipitate. Washing with chloroform/methanol solution for three times to obtain polyether thiourea product, placing the product into a polytetrafluoroethylene mold, vacuum drying at 140 deg.C for 12h, cooling, and placing into a drying oven for later use.
0.91g of 1.1 wt% high-conductivity PEDOT/PSS solution is added into 0.7g of 1.0 wt% PETU solution, then 0.003g of dimethyl sulfoxide is added, and the mixture is stirred for 12 hours at the temperature of 60 ℃ to ensure that the mixed solution is fully crosslinked. And (3) adding 0.08g of nano silicon powder into a cross-linked product (PEDOT: PSS-PETU) of the PEDOT: PSS and the PETU to stir magnetons (firstly, the nano silicon is uniformly mixed by fast stirring, and then, the nano silicon is fully coated by the cross-linked product (PEDOT: PSS-PETU) by slow stirring to obtain a product of the silicon coated by the PEDOT: PSS-PETU. And finally, adding Li-Nafion @ GN into the product to obtain final negative electrode slurry, wherein Si in the negative electrode slurry is PEDOT, PSS, PETU, Li-Nafion @ GN is 8:1:0.7: 0.3. The slurry was coated on a copper current collector by a doctor blade method to obtain a wet silicon negative electrode. And (3) putting the wet silicon cathode into a vacuum oven at 100 ℃ for pre-drying for 12 hours, and then completely drying in the vacuum oven at 180 ℃ for 6 hours to finally obtain the silicon cathode for experiments. The thickness of the experimental silicon negative electrode and the mass loading of the active material were about 10 μm and 0.75mg cm, respectively -2 。
Example 3
A method of making a silicon electrode, the method comprising:
weighing 0.5Nafion particles by using an electronic balance, slowly adding the Nafion particles into a hydrothermal reaction kettle, adding 5.59g of water and 4.41g of ethanol (namely the volume ratio of the water to the ethanol is 1: 1) into the reaction kettle, covering the reaction kettle, putting the reaction kettle into a 230 ℃ oven, heating for 4 hours to uniformly dissolve Nafion into a mixed solution of the water and the ethanol, and preparing a Nafion uniform solution with the mass fraction of 5%. 10g of Nafion homogeneous solution was added to the reagent bottle with magnetons. Adding 25.2mg of LiOH. H into a reagent bottle 2 And (4) O powder. And (3) carrying out ultrasonic treatment for 10min at normal temperature to fully and uniformly dissolve the solute, and then stirring for 2h at 60 ℃ to obtain a Li-Nafion uniform solution with the mass percentage of about 5%. 0.02 mass percent of titanium carbide (MXene) and 0.8 mass percent of 5 mass percent of Li-Nafion solution are added into a reagent bottle with magnetons, so that the mass ratio of MXene to Li-Nafion is 1: 2, carrying out ultrasonic treatment for 30min to uniformly distribute MXene in the solution. And then placing the reagent bottle containing the mixed solution of MXene and Li-Nafion into an oil bath kettle at 60 ℃, stirring magnetons to ensure that the Li-Nafion is fully adsorbed on the MXene, and finally obtaining the Li-Nafion-coated lithium-conducting and conductive MXene network (Li-Nafion @ MXene).
4.45g (0.025mol) of 1,1 '-thiocarbonyldiimidazole was charged in a three-necked flask equipped with magnetons, and 12.5mL of an ultra-dry solution of DMF was slowly added to the flask, and 1,1' -thiocarbonyldiimidazole was sufficiently dissolved in DMF with magnetic stirring to obtain a yellowish brown transparent solution. Under the protection of high-purity nitrogen, 3.875g (0.0263mol) of 1, 2-bis (2-aminoethoxy) ethane liquid was added to the above mixed solution, and the above mixed solution was continuously stirred at 25 ℃ for 24 hours to obtain a brown turbid solution. 25.0mL of chloroform was weighed into the above turbid mixed solution. The solution was then poured into 375mL of diethyl ether (Et2O), followed by a turbidity of the Et2O solution with a tan precipitate settling at the bottom of the beaker. The cloudy solution was poured off and chloroform was added to the beaker to dissolve the tan precipitate. Washing with chloroform/methanol solution for three times to obtain polyether thiourea product, placing the product into a polytetrafluoroethylene mold, vacuum drying at 140 ℃ for 12h, cooling and placing into a drying oven for later use.
0.91g of a 1.1 wt% highly conductive PEDOT: PSS solution was added to 0.7g of 1.0 wt% PETU solution, then 0.003g dimethyl sulfoxide is added, and the mixture is stirred for 12 hours at 60 ℃ to ensure that the mixed solution is fully crosslinked. 0.08g of nano silicon powder is taken and added into a cross-linked product of PEDOT, PSS and PETU (PEDOT, PSS-PETU), and magnetons are stirred for 4 hours (firstly, the nano silicon is stirred quickly to be mixed evenly, and then, the cross-linked product of the PEDOT, PSS-PETU is fully coated on the nano silicon by stirring slowly), so that a product of the silicon coated by the PEDOT, PSS-PETU is obtained. And finally, adding Li-Nafion @ MXene into the product to obtain final negative electrode slurry, wherein Si in the negative electrode slurry is PEDOT, PSS, PETU and Li-Nafion @ MXene in a ratio of 8:1:0.7: 0.3. The slurry was coated on a copper current collector by a doctor blade method to obtain a wet silicon negative electrode. And (3) putting the wet silicon cathode into a vacuum oven at 100 ℃ for pre-drying for 12 hours, and then completely drying in the vacuum oven at 180 ℃ for 6 hours to finally obtain the silicon cathode for experiments. The thickness of the experimental silicon negative electrode and the mass loading of the active material were about 10 μm and 0.75mg cm, respectively -2 。
Example 4
A method of making a silicon electrode, the method comprising:
weighing 0.5Nafion particles by using an electronic balance, slowly adding the Nafion particles into a hydrothermal reaction kettle, adding 5.59g of water and 4.41g of ethanol (namely the volume ratio of the water to the ethanol is 1: 1) into the reaction kettle, covering the reaction kettle, putting the reaction kettle into a 230 ℃ oven, heating for 4 hours to uniformly dissolve Nafion into a mixed solution of the water and the ethanol, and preparing a Nafion uniform solution with the mass fraction of 5%. 10g of Nafion homogeneous solution was added to a reagent bottle with magnetons. Adding 25.2mg of LiOH. H into a reagent bottle 2 And (4) O powder. And (3) carrying out ultrasonic treatment for 10min at normal temperature to fully and uniformly dissolve the solute, and then stirring for 2h at 60 ℃ to obtain a Li-Nafion uniform solution with the mass percent of about 5%. 0.02MoS 2 Adding 0.8g of 5% Li-Nafion solution into a reagent bottle with a magneton in the reagent, and allowing MoS to react 2 The mass ratio of the Li to Nafion is 1: 2, followed by sonication for 30min to MoS 2 The solution is distributed evenly. Then the MoS is filled in 2 Placing the reagent bottle mixed with the Li-Nafion mixed solution into an oil bath pan at 60 ℃, and stirring by magnetons to ensure that the Li-Nafion is fully adsorbed on MoS 2 Finally, the Li-Nafion coated lithium conducting and conducting MoS is obtained 2 Network (Li-Nafion @ MoS) 2 )。
4.45g (0.025mol) of 1,1 '-thiocarbonyldiimidazole was charged in a three-necked flask equipped with magnetons, and 12.5mL of an ultra-dry solution of DMF was slowly added to the flask, and 1,1' -thiocarbonyldiimidazole was sufficiently dissolved in DMF with magnetic stirring to obtain a yellowish brown transparent solution. Under the protection of high-purity nitrogen, 3.875g (0.0263mol) of 1, 2-bis (2-aminoethoxy) ethane liquid was added to the above mixed solution, and the above mixed solution was continuously stirred at 25 ℃ for 24 hours to obtain a brown turbid solution. 25.0mL of chloroform was weighed into the above cloudy mixture solution. The above solution was then poured into 375mL of diethyl ether (Et2O) and the Et2O solution became cloudy with a tan precipitate settling at the bottom of the beaker. The cloudy solution was poured off and chloroform was added to the beaker to dissolve the tan precipitate. Washing with chloroform/methanol solution for three times to obtain polyether thiourea product, placing the product into a polytetrafluoroethylene mold, vacuum drying at 140 deg.C for 12h, cooling, and placing into a drying oven for later use.
0.91g of 1.1 wt% high-conductivity PEDOT/PSS solution is added into 0.7g of 1.0 wt% PETU solution, then 0.003g of dimethyl sulfoxide is added, and the mixture is stirred for 12 hours at the temperature of 60 ℃ to ensure that the mixed solution is fully crosslinked. 0.08g of nano silicon powder is taken and added into a cross-linked product of PEDOT, PSS and PETU (PEDOT, PSS-PETU), and magnetons are stirred for 4 hours (firstly, the nano silicon is stirred quickly to be mixed evenly, and then, the cross-linked product of the PEDOT, PSS-PETU is fully coated on the nano silicon by stirring slowly), so that a product of the silicon coated by the PEDOT, PSS-PETU is obtained. Finally, Li-Nafion @ MoS is added into the product 2 Obtaining final cathode slurry, wherein Si in the cathode slurry is PEDOT, PSS, PETU, Li-Nafion @ MoS 2 Is 8:1:0.7: 0.3. The slurry was coated on a copper current collector by a doctor blade method to obtain a wet silicon negative electrode. And (3) putting the wet silicon cathode into a vacuum oven at 100 ℃ for pre-drying for 12 hours, and then completely drying in the vacuum oven at 180 ℃ for 6 hours to finally obtain the silicon cathode for experiments. The thickness of the experimental silicon negative electrode and the mass loading of the active material were about 10 μm and 0.75mg cm, respectively -2 。
Comparative example 1
A method of making a silicon electrode, the method comprising:
0.08g of nanosilicon, 0.01g of polyacrylic acid (PAA), 0.01g of conductive Carbon Black (CB) were added to a mortar and ground together for 30 minutes. Subsequently, the milled mixed powder was transferred to a 10mL beaker, and 1.5mL of deionized water was added and stirring was continued for 12 hours to obtain a control wet slurry. The wet slurry was coated on a copper current collector by a doctor blade method, and then dried in vacuum at 100 ℃ for 12 hours.
Related experiments:
the silicon electrodes obtained in examples 1 to 4 and comparative example 1 were subjected to performance tests, and the test results are shown in the following table.
Figure BDA0003701046160000091
From the above table, it can be seen that the capacity exertion and the cycling stability of the silicon electrode prepared by the method provided in the embodiments of the present application are superior to those of the conventional electrode at both normal temperature and low temperature. Meanwhile, the high-rate charge-discharge performance of the electrode is superior to that of the traditional electrode at normal temperature and low temperature.
Detailed description of the drawings 2-4:
as shown in fig. 2, which is an SEM image of the silicon electrode provided in example 1, it can be clearly seen that the carbon nanotubes are closely attached to the silicon particle clusters to form a continuous three-dimensional percolated ordered structure. Under the initiation of the lithium conducting polymer, a phenomenon that continuous lithium conducting polymer modified carbon nanotubes are wound on silicon particle clusters is formed inside the silicon electrode provided by example 1.
As shown in fig. 3, the cells assembled for the silicon electrodes provided in example 1 and comparative example 1 exhibited cycling performance at normal and low temperatures. Wherein the ordinate represents the capacity exerted by the battery, and the abscissa represents the number of charge and discharge cycles. PEDOT-PSS-PETU/Li-nafion @ CNT/Si represents the electrode provided in example 1, and PAA/CB/Si represents the electrode provided in proportion to 1, and it can be seen from the figure that the capacity exertion and the cycling stability of the electrode provided in example 1 are superior to those of the electrode provided in comparative example 1 at normal temperature and low temperature.
As shown in fig. 4, the rate performance at normal temperature and low temperature of the cells assembled for the silicon electrodes provided in example 1 and comparative example 1; wherein the ordinate represents the capacity exerted by the battery, and the abscissa represents the number of charge and discharge cycles. PEDOT, PSS-PETU/Li-nafion @ CNT/Si represents the electrode provided by the example 1, PAA/CB/Si represents the electrode provided by the comparative example 1, and the electrode provided by the example 1 has better large-rate charge and discharge performance than the electrode provided by the comparative example 1 at normal temperature and low temperature.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
the method provided by the embodiment of the invention utilizes the lithium conducting polymer to coat the inorganic conducting material to form a lithium conducting framework; the lithium conducting polymer is utilized to tightly connect the conducting material on the surface of the silicon particles, so that the electrical contact separation in the circulation process is prevented; a tight interface formed by the lithium conducting framework and the silicon particles can improve an electron transmission path on the surface of the silicon particles and the diffusion speed of lithium ions; the lithium conducting and conducting framework and the lithium conducting and conducting interface can reduce the impedance of the silicon negative electrode and improve the diffusion rate of lithium ions.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. A method of making a silicon electrode, the method comprising:
mixing an inorganic conductive material with a lithium-conducting polymer solution to obtain a mixed solution containing a lithium-conducting framework;
mixing nano silicon and a bonding solution to obtain bonding slurry;
mixing the mixed solution containing the lithium-conducting conductive framework with the bonding slurry to enable the lithium-conducting conductive framework to be connected with the surface of the nanometer silicon to form a tight interface, so as to obtain electrode slurry;
and coating the electrode slurry, and then drying to obtain the silicon electrode.
2. The method of manufacturing a silicon electrode of claim 1, wherein the inorganic conductive material comprises at least one of carbon nanotubes, graphene, titanium carbon, and molybdenum disulfide.
3. The method of making a silicon electrode of claim 1, wherein the lithium conducting polymer solution is a lithiated Nafion solution.
4. The method of manufacturing a silicon electrode according to claim 1, wherein the raw material of the bonding solution comprises a conductive polymer and a stretchable self-healing polymer.
5. The method of claim 4, wherein the conductive polymer is poly 3, 4-ethylenedioxythiophene: polystyrene sulfonate.
6. The method of forming a silicon electrode of claim 4, wherein the stretchable self-healing polymer is polyether thiourea.
7. The method of claim 4, wherein the mixing of the nanosilicon and the bonding solution is performed using a rapid followed by a slow gradient.
8. The method of manufacturing a silicon electrode of claim 4, wherein the drying comprises low temperature pre-drying and high temperature drying.
9. A silicon electrode produced by the method of producing a silicon electrode according to any one of claims 1 to 8.
10. Use of a silicon electrode according to claim 9 in the negative electrode of a lithium battery.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115224278A (en) * 2022-09-20 2022-10-21 楚能新能源股份有限公司 Conductive composite binder for silicon anode, preparation method and lithium ion battery

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004063411A (en) * 2002-07-31 2004-02-26 Jfe Chemical Corp Complex graphite material, its manufacturing method, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
CN110635137A (en) * 2019-09-25 2019-12-31 上海大学(浙江·嘉兴)新兴产业研究院 Conductive polymer binder and preparation method thereof, silicon-based negative plate and application thereof
CN111662418A (en) * 2020-05-22 2020-09-15 远景动力技术(江苏)有限公司 Lithiation functional polymer for lithium ion battery and its preparation method and application
JP2021077439A (en) * 2019-11-05 2021-05-20 学校法人同志社 Lithium ion secondary battery

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004063411A (en) * 2002-07-31 2004-02-26 Jfe Chemical Corp Complex graphite material, its manufacturing method, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
CN110635137A (en) * 2019-09-25 2019-12-31 上海大学(浙江·嘉兴)新兴产业研究院 Conductive polymer binder and preparation method thereof, silicon-based negative plate and application thereof
JP2021077439A (en) * 2019-11-05 2021-05-20 学校法人同志社 Lithium ion secondary battery
CN111662418A (en) * 2020-05-22 2020-09-15 远景动力技术(江苏)有限公司 Lithiation functional polymer for lithium ion battery and its preparation method and application

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115224278A (en) * 2022-09-20 2022-10-21 楚能新能源股份有限公司 Conductive composite binder for silicon anode, preparation method and lithium ion battery

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