CN112421048A - Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost - Google Patents

Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost Download PDF

Info

Publication number
CN112421048A
CN112421048A CN202011369100.3A CN202011369100A CN112421048A CN 112421048 A CN112421048 A CN 112421048A CN 202011369100 A CN202011369100 A CN 202011369100A CN 112421048 A CN112421048 A CN 112421048A
Authority
CN
China
Prior art keywords
silicon
graphite
lithium battery
nano
low cost
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.)
Withdrawn
Application number
CN202011369100.3A
Other languages
Chinese (zh)
Inventor
陈庆
廖健淞
司文彬
李钧
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.)
Chengdu New Keli Chemical Science Co Ltd
Original Assignee
Chengdu New Keli Chemical Science 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 Chengdu New Keli Chemical Science Co Ltd filed Critical Chengdu New Keli Chemical Science Co Ltd
Priority to CN202011369100.3A priority Critical patent/CN112421048A/en
Publication of CN112421048A publication Critical patent/CN112421048A/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention provides a method for preparing a graphite-coated nano-silicon lithium battery cathode material at low cost4+And then, carrying out plasma treatment by using hydrogen as a gas source to obtain a nano silicon particle intercalation graphite plate, connecting the nano silicon particle intercalation graphite plate and a metal lithium sheet into a direct-current power supply, carrying out lithium intercalation in a lithium hexafluorophosphate/ethylene carbonate solution, and then drying and crushing the graphite plate to obtain the graphite-coated nano silicon lithium battery cathode material. The graphite coating provided by the inventionThe cathode material of the silicon-lithium battery has excellent dispersibility, can effectively inhibit the volume expansion of the cathode material, has easily obtained raw materials, low cost and simple process, and has obvious cost advantage compared with the prior art.

Description

Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost
Technical Field
The invention relates to the technical field of lithium battery cathode materials, in particular to a method for preparing a graphite-coated nano silicon lithium battery cathode material at low cost.
Background
The lithium ion battery has the advantages of large energy density, long cycle life, high working voltage and the like, and is one of the most promising energy storage technologies. At present, lithium ion batteries have been widely used in the field of portable consumer electronics, and also have great potential in the fields of the electric vehicle industry, the power grid energy storage industry and the like. The capacity of the lithium ion battery is determined by active lithium ions of a positive electrode material and the lithium-intercalation and deintercalation capability of a negative electrode material, and the stability of the positive electrode and the negative electrode in various environments determines the performance of the battery and even seriously affects the safety of the battery, so that the performance of the electrode determines the comprehensive performance of the lithium ion battery to a certain extent.
In the lithium ion battery electrode materials, the current commercialized lithium ion battery cathode materials are mainly graphite carbon cathode materials, graphite carbon has the advantages of good conductivity, high crystallinity, good layered structure, suitability for the deintercalation of lithium and high charge-discharge specific capacity, the theoretical specific capacity is only 372mAh/g, and the further development of the lithium ion battery is severely limited. The silicon-based material is a research system with the highest theoretical specific capacity in the research of the negative electrode material, the theoretical specific capacity is up to 4200mAh/g, and the silicon-based material is considered to be an alternative product of the carbon negative electrode material due to the low lithium intercalation potential, the low atomic mass and the high energy density.
However, silicon as a semiconductor material has low self-conductivity, and during an electrochemical cycle, the volume of the material expands and contracts to a large extent, so that the material is gradually pulverized and the structure collapses, and finally, an electrode active substance and a current collector fall off and lose electrical contact. Meanwhile, the price of the nano silicon raw material is relatively high, and the cost of the nano silicon raw material as a lithium battery cathode material is too high, so that commercialization is difficult to realize. Therefore, there is a need for further improvement in dispersibility of the silicon-carbon negative electrode material and reduction in raw material cost.
Chinese patent application No. 201210169022.1 discloses a silicon-carbon composite cathode material of a lithium ion battery and a preparation method thereofThe method comprises the following steps: preparing graphite dispersion liquid and silicon grinding dispersion liquid, adding the silicon grinding dispersion liquid into the graphite dispersion liquid, and carrying out heat treatment. The Chinese patent application No. 201410282686.8 discloses a preparation method of a silicon-carbon anode material, which comprises the following steps: (1) placing a catalyst in a chemical vapor deposition reaction chamber; (2) heating the chemical vapor deposition reaction chamber, introducing a reaction gas source and a carrier gas into the chemical vapor deposition reaction chamber, and reacting Si-SiO generated in the chemical vapor deposition reaction processxPreparing a precursor of the silicon-carbon negative electrode material by using a dynamically rotating carbon substrate subjected to carboxylation treatment; (3) and carrying out organic pyrolytic carbon coating treatment on the precursor, and then calcining in a non-oxidizing atmosphere to obtain the silicon-carbon negative electrode material. The Chinese patent application No. 201210534860.4 discloses a preparation method of a graphene-coated silicon-carbon composite negative electrode material, which comprises the following steps: uniformly dispersing nano silicon and graphite micropowder into a dispersion liquid of graphene oxide, carrying out spray drying, carrying out heat treatment under an inert protective atmosphere, and then cooling along with a furnace to obtain the graphene-coated silicon-carbon composite negative electrode material.
In order to significantly improve the dispersibility of the lithium battery silicon negative electrode material, inhibit the volume expansion effect and effectively reduce the raw material cost of the silicon negative electrode material, a novel composite nano silicon negative electrode material is necessary to be provided, so that the development and application of the lithium battery silicon-based negative electrode material are promoted.
Disclosure of Invention
Aiming at the problems of poor dispersibility, easy volume expansion and high raw material cost of the conventional silicon-based negative electrode material of the lithium battery, the invention provides a method for preparing the negative electrode material of the graphite-coated nano silicon lithium battery at low cost, so that the dispersibility of the silicon negative electrode material is improved, the volume expansion of the negative electrode material is effectively inhibited, the preparation process is simple, and the cost is reduced.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for preparing a graphite-coated nano-silicon lithium battery cathode material at low cost comprises the steps of adding an expanded graphite plate into silicon tetrachloride, carrying out heating reaction under the argon atmosphere to obtain a modified expanded graphite plate, carrying out plasma treatment by using hydrogen as a gas source to obtain a nano-silicon particle intercalated graphite plate, connecting the nano-silicon particle intercalated graphite plate and a metal lithium sheet into a direct-current power supply anode, treating the nano-silicon particle intercalated graphite plate and the metal lithium sheet in a lithium hexafluorophosphate/ethylene carbonate electrolytic solution, drying and crushing the graphite plate to obtain the graphite-coated nano-silicon lithium battery cathode material, and specifically comprises the following steps:
(1) soaking an expanded graphite plate in silicon tetrachloride, sealing a system, replacing the system with argon, heating the system, carrying out heat preservation treatment, naturally cooling to room temperature after the reaction is finished, taking out the plate, and drying to obtain the Si-loaded plate4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, and then cooling is carried out to room temperature, so as to obtain a nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet in a lithium hexafluorophosphate/ethylene carbonate solution for treatment to ensure that the graphite plate is fully embedded with lithium, taking out the graphite plate, drying and crushing to obtain the graphite-coated nano silicon lithium battery cathode material.
Preferably, the expanded graphite sheet in the step (1) is a square or rectangular sheet, and the thickness of the sheet is 10-15 mm.
Preferably, the temperature of the heat preservation treatment in the step (1) is controlled at 300 ℃ of 100-.
Further preferably, the temperature of the heat-retaining treatment in the step (1) is controlled to 250 ℃.
Preferably, the Si is supported in the step (1)4+In the preparation of the modified expanded graphite plate, the mass ratio of the expanded graphite plate to the silicon tetrachloride is 1-10: 30-40.
Preferably, the temperature of the plasma treatment in the step (2) is controlled at 1100 ℃ and 1200 ℃, and the treatment time is 1-6 h.
Further preferably, the temperature of the plasma treatment in the step (2) is controlled to be 1100 ℃ and 1200 ℃, and the plasma treatment is carried out for 2-3 h.
Preferably, the voltage of the direct current power supply in the step (3) is 2-3V, and the current density is 10-100mA/g (by mass of silicon tetrachloride).
Preferably, the molar ratio of the lithium hexafluorophosphate/ethylene carbonate solution in the step (3) is 1 to 1.2 mol/L.
Preferably, the treatment time in step (3) is 2-4 h.
Preferably, the graphite plates in step (3) are pulverized into fine particles having a particle size of less than 10 μm.
Silicon-based anode materials are known to be one of the potential choices for upgrading carbon-based anodes of lithium ion batteries due to their excellent performance. However, silicon has disadvantages as a negative electrode material for lithium ion batteries. Silicon is a semiconductor material and has low intrinsic conductivity. In addition, in the electrochemical cycle process, the lithium ion intercalation and deintercalation can cause the silicon-based material to expand and contract by more than 300% in volume, and the generated mechanical acting force can gradually pulverize the material to cause structural collapse, so that the electrode active substance is separated from the current collector and loses electric contact, and the cycle performance of the battery is greatly reduced. In order to improve the conductivity and cycle performance of the silicon-based negative electrode material and improve the structural stability of the material in the cycle process, the silicon material is generally subjected to nano-crystallization and compounding. However, the nano silicon material inevitably aggregates due to the surface effect in the preparation process, thereby reducing the electrochemical performance; in addition, the silicon-carbon composite cathode material commonly used at present has high cost due to high price of silicon raw materials and complex preparation process, and is difficult to realize commercial production. According to the invention, silicon is loaded on the expanded graphite creatively, and then the silicon-lithium alloy is formed under the action of lithium intercalation, so that the silicon-lithium alloy is formed between the layers of the expanded graphite to form the graphite-coated nano silicon-lithium negative electrode material, and the problems are effectively solved.
The method comprises the steps of firstly taking an expanded graphite plate as a raw material, immersing the expanded graphite plate in silicon tetrachloride which is a silicon source with low cost, and heating and insulating the expanded graphite plate in an argon atmosphere to fully activate the expanded graphite, enlarge interlayer spacing and prepare Si in the silicon tetrachloride4+Is easier to be inserted intoPut between graphite layers to obtain loaded Si4+The modified expanded graphite sheet of (1).
Further, the loaded Si is treated by utilizing a microwave plasma treatment technology and utilizing hydrogen as a gas source and a reducing agent4+The intercalated Si4+ in the modified expanded graphite plate is reduced into nano-silicon particles, and simultaneously, graphite is used as a wave-absorbing material, so that the van der Waals force between graphite layers can be effectively reduced in the microwave treatment process, the graphene sheets can be conveniently prepared by stripping in the subsequent process, the silicon is coated by the graphene sheets, and simultaneously, the reduced nano-silicon particles can be better loaded between the graphite layers in an intercalated manner, so that the nano-silicon particle intercalated graphite plate is obtained.
Furthermore, the nano silicon particle intercalated graphite plate is connected to a direct current power supply anode, the metal lithium sheet is connected to a direct current power supply cathode and fixed in electrolyte (lithium hexafluorophosphate/ethylene carbonate solution), under the action of current, nano silicon particles and lithium ions are compounded to form silicon lithium alloy, the net is arranged between layers of graphene, and the graphite plate is dried and crushed to obtain fine particles, namely particles for fixing the silicon lithium alloy between the graphite layers, so that the volume expansion of silicon is inhibited, the preparation process is simple, and the low-cost preparation of the composite silicon-based cathode material with excellent performance is realized.
Compared with the prior art, the invention provides a method for preparing a graphite-coated nano-silicon lithium battery cathode material with low cost, which has the outstanding characteristics and excellent effects that:
1. the graphite-coated nano-silicon lithium battery cathode material prepared by the method can effectively inhibit the volume expansion of the cathode material.
2. According to the preparation method, the silicon tetrachloride intercalated expanded graphite is reduced into nano silicon particles, and lithium is further embedded into the graphite to form the silicon-lithium alloy by using a battery principle, so that the silicon-lithium is coated by the graphene.
3. According to the invention, the graphene-coated nano silicon negative electrode material is directly prepared from silicon tetrachloride and expanded graphite with low cost, the preparation process is simple, and the raw materials are easy to obtain, so that the method has an obvious cost advantage compared with the existing process.
Drawings
FIG. 1: the method of the invention is used for preparing the graphite-coated nano-silicon lithium battery cathode material, and the process flow diagram is as follows: 1-impregnating the expanded graphite sheet with silicon tetrachloride; 2-hydrogen reduction; 3-treatment in electrolyte; 4-drying and crushing; 5-graphite coating nano silicon lithium battery cathode material.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.
Example 1
(1) Soaking 6kg of square expanded graphite plate with the thickness of 10mm in 35kg of silicon tetrachloride, sealing the system and replacing the system by using argon, heating the system to 250 ℃, preserving heat for 1.5h, naturally cooling to room temperature after the reaction is finished, taking out the plate and drying to obtain the loaded Si4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled at 1150 ℃, the treatment is carried out for 3 hours, and then the modified expanded graphite plate is cooled to room temperature to obtain a nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet to a 1.1mol/L lithium hexafluorophosphate/ethylene carbonate solution, treating for 2h, taking out the graphite plate, drying, and crushing into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon lithium battery cathode material, wherein the voltage of the direct current power supply is 2.5V, and the current density is 60mA/g (by the mass of silicon tetrachloride).
Example 2
(1) Soaking 3kg of rectangular expanded graphite plate with the thickness of 12mm in 38kg of silicon tetrachloride, sealing the system, replacing the system with argon, heating the system to 150 ℃, preserving heat for 2 hours, and reactingNaturally cooling to room temperature after the completion, taking out the plate and drying to obtain the load Si4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled to be 1120 ℃, the treatment is carried out for 5 hours, and then the modified expanded graphite plate is cooled to the room temperature, so as to obtain the nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet to a 1.1mol/L lithium hexafluorophosphate/ethylene carbonate solution, treating for 3h, taking out the graphite plate, drying, and crushing into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon lithium battery cathode material, wherein the voltage of the direct current power supply is 2.5V, and the current density is 60mA/g (by the mass of silicon tetrachloride).
Example 3
(1) Soaking 8kg of square or rectangular expanded graphite plate with the thickness of 14mm in 32kg of silicon tetrachloride, sealing the system, replacing the system with argon, heating the system to 250 ℃, carrying out heat preservation treatment for 1h, naturally cooling to room temperature after the reaction is finished, taking out the plate, and drying to obtain the Si-loaded plate4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled at 1180 ℃, the treatment is carried out for 2 hours, and then the modified expanded graphite plate is cooled to the room temperature, so that the nano silicon particle intercalated graphite plate is obtained;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet to a 1.1mol/L lithium hexafluorophosphate/ethylene carbonate solution, treating for 4 hours, taking out the graphite plate, drying, and crushing into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon lithium battery cathode material, wherein the voltage of the direct current power supply is 2.5V, and the current density is 60mA/g (by mass of silicon tetrachloride).
Example 4
(1) Adding 10kgSoaking a square expanded graphite plate with the thickness of 10mm in 30kg of silicon tetrachloride, sealing the system, replacing the system with argon, heating the system to 300 ℃, carrying out heat preservation treatment for 1h, naturally cooling to room temperature after the reaction is finished, taking out the plate, and drying to obtain a Si-loaded plate4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled at 1200 ℃, the treatment is carried out for 1 hour, and then the modified expanded graphite plate is cooled to the room temperature, so as to obtain the nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet to a 1.1mol/L lithium hexafluorophosphate/ethylene carbonate solution, treating for 3h, taking out the graphite plate, drying, and crushing into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon lithium battery cathode material, wherein the voltage of the direct current power supply is 2.5V, and the current density is 60mA/g (by the mass of silicon tetrachloride).
Example 5
(1) Soaking 1kg of square expanded graphite plate with the thickness of 10mm in 40kg of silicon tetrachloride, sealing the system and replacing the system by using argon, heating the system to 100 ℃, carrying out heat preservation treatment for 2 hours, naturally cooling to room temperature after the reaction is finished, taking out the plate and drying to obtain the Si-loaded plate4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled at 1100 ℃, the treatment is carried out for 6 hours, and then the modified expanded graphite plate is cooled to the room temperature, so as to obtain the nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet to a 1.1mol/L lithium hexafluorophosphate/ethylene carbonate solution, treating for 4 hours, taking out the graphite plate, drying, and crushing into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon lithium battery cathode material, wherein the voltage of the direct current power supply is 2.5V, and the current density is 60mA/g (by mass of silicon tetrachloride).
Comparative example 1
(1) Soaking 6kg of square expanded graphite plate with the thickness of 10mm in 35kg of silicon tetrachloride, sealing the system and replacing the system by using argon, heating the system to 250 ℃, preserving heat for 1.5h, naturally cooling to room temperature after the reaction is finished, taking out the plate and drying to obtain the loaded Si4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, the temperature is controlled at 1150 ℃, the treatment is carried out for 3 hours, and then the modified expanded graphite plate is cooled to room temperature to obtain a nano silicon particle intercalated graphite plate; and crushing the mixture into particles with the particle size of less than 10 mu m to obtain the graphite-coated nano silicon battery negative electrode material.
Comparative example 2
Compared with the embodiment 1, the comparative example 2 uses nano silicon and expanded graphite powder as raw materials, the nano silicon and the expanded graphite powder are uniformly mixed with CMC binder, NMP dispersant and deionized water according to the mass ratio of 10:50:3:3:80 to prepare suspension, and the suspension is subjected to ball milling, filtering and drying, and then is subjected to vacuum heat treatment at 1200 ℃ for 5 hours to obtain the silicon-carbon negative electrode material.
The test method comprises the following steps:
and (3) testing the cycle performance: the silicon negative electrode material samples prepared in examples 1 to 5 and comparative examples 1 to 2 of the present invention were used as an active material, mixed with PVDF and Super-P in a mass ratio of 8:1:1, prepared into a slurry in NMP solvent, coated on the surface of copper foil as a positive electrode, lithium sheet as a negative electrode, lithium hexafluorophosphate/ethylene carbonate as an electrolyte, polypropylene as a separator, assembled into a CR2032 button cell, the cycle performance of the cell was tested at a current density of 0.4mA/g, the initial discharge capacity at 50 cycles and 100 cycles was recorded, the capacity retention at 100 cycles was calculated, and the test results are shown in table 1.
Table 1:
performance index Initial discharge capacity (mAh/g) 50 circles discharge capacity (mAh/g) 100 circles discharge capacity (mAh/g) Capacity retention rate at 100 cycles (%)
Example 1 588.4 544.3 522.1 88.73
Example 2 588.2 544.1 521.9 88.73
Example 3 588.7 544.8 522.2 88.74
Example 4 589.1 545.1 522.9 88.76
Example 5 588.1 543.5 521.3 88.64
Comparative example 1 592.7 533.8 479.2 80.85
Comparative example 2 574.6 459.1 360.3 62.70
As can be seen from table 1, through the performance test, the initial discharge capacity cycle performance of the negative electrode material sample of the example of the present invention is significantly better than that of the comparative example 1 and the comparative example 2; comparative example 1, because lithium was not intercalated into graphite, the buffer space was reduced when silicon was expanded, affecting the cyclability. The comparative example 2 is a silicon-carbon cathode prepared by the conventional silicon-carbon sintering composite process at present, although the coating effect is good, the buffering space is small, and the circulation stability is poor.

Claims (9)

1. A method for preparing a graphite-coated nano-silicon lithium battery cathode material at low cost is characterized in that an expanded graphite plate is added into silicon tetrachloride, a modified expanded graphite plate is obtained through heating reaction in an argon atmosphere, then, hydrogen is used as a gas source to perform plasma treatment to obtain a nano-silicon particle intercalated graphite plate, the nano-silicon particle intercalated graphite plate and a metal lithium sheet are connected to a direct-current power supply anode and treated in a lithium hexafluorophosphate/ethylene carbonate solution, and then, the graphite plate is dried and crushed to obtain the graphite-coated nano-silicon lithium battery cathode material, and the specific preparation method is as follows:
(1) soaking an expanded graphite plate in silicon tetrachloride, sealing a system, replacing the system with argon, heating the system, carrying out heat preservation treatment, naturally cooling to room temperature after the reaction is finished, taking out the plate, and drying to obtain the Si-loaded plate4+The modified expanded graphite sheet of (1);
(2) the obtained supported Si4+The modified expanded graphite plate is placed in microwave plasma equipment, then plasma treatment is carried out by using hydrogen as a gas source, and then cooling is carried out to room temperature, so as to obtain a nano silicon particle intercalated graphite plate;
(3) and (2) connecting the obtained nano silicon particle intercalated graphite plate to a direct current power supply anode, connecting a metal lithium sheet to a direct current power supply cathode, fixing the metal lithium sheet in a lithium hexafluorophosphate/ethylene carbonate solution for treatment to ensure that lithium is fully embedded into graphite, taking out the graphite plate, drying and crushing to obtain the graphite-coated nano silicon lithium battery cathode material.
2. The method for preparing the negative electrode material of the graphite-coated nano-silicon lithium battery at low cost according to claim 1, wherein the expanded graphite sheet in the step (1) is a square or rectangular sheet with a thickness of 10-15 mm.
3. The method for preparing the graphite-coated nano-silicon lithium battery anode material with low cost as claimed in claim 1, wherein the temperature of the heat preservation treatment in the step (1) is controlled at 300 ℃ for 1-2 h.
4. The method for preparing the graphite-coated nano-silicon lithium battery anode material at low cost according to claim 1, wherein the Si-loaded nano-silicon lithium battery anode material in the step (1)4+In the preparation of the modified expanded graphite plate, the mass ratio of the expanded graphite plate to the silicon tetrachloride is 1-10: 30-40.
5. The method for preparing the graphite-coated nano-silicon lithium battery anode material at low cost as claimed in claim 1, wherein the temperature of the plasma treatment in the step (2) is controlled at 1100 ℃ and 1200 ℃ for 1-6 h.
6. The method for preparing the negative electrode material of the graphite-coated nano silicon-lithium battery at low cost according to claim 1, wherein the voltage of the direct current power supply in the step (3) is 2-3V, and the current density is 10-100mA/g (by mass of silicon tetrachloride).
7. The method for preparing the negative electrode material of the graphite-coated nano-silicon lithium battery at low cost according to claim 1, wherein the molar ratio of the lithium hexafluorophosphate/ethylene carbonate solution in the step (3) is 1-1.2 mol/L.
8. The method for preparing the graphite-coated nano-silicon lithium battery anode material at low cost according to claim 1, wherein the treatment time in the step (3) is 2-4 h.
9. The method for preparing the negative electrode material of the graphite-coated nano-silicon lithium battery at low cost according to claim 1, wherein the step (3) comprises the step of crushing graphite plates into particles with the particle size of less than 10 μm.
CN202011369100.3A 2020-11-30 2020-11-30 Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost Withdrawn CN112421048A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011369100.3A CN112421048A (en) 2020-11-30 2020-11-30 Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011369100.3A CN112421048A (en) 2020-11-30 2020-11-30 Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost

Publications (1)

Publication Number Publication Date
CN112421048A true CN112421048A (en) 2021-02-26

Family

ID=74828917

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011369100.3A Withdrawn CN112421048A (en) 2020-11-30 2020-11-30 Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost

Country Status (1)

Country Link
CN (1) CN112421048A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114361393A (en) * 2022-01-07 2022-04-15 山东大学 Method for simply preparing self-supporting silicon cathode and application of self-supporting silicon cathode in lithium/sodium battery
CN114695833A (en) * 2022-03-01 2022-07-01 北京化工大学 Lithium dendrite inhibition device, system and method for lithium metal battery negative electrode material
US11590568B2 (en) 2019-12-19 2023-02-28 6K Inc. Process for producing spheroidized powder from feedstock materials
US11633785B2 (en) 2019-04-30 2023-04-25 6K Inc. Mechanically alloyed powder feedstock
US11717886B2 (en) 2019-11-18 2023-08-08 6K Inc. Unique feedstocks for spherical powders and methods of manufacturing
US11839919B2 (en) 2015-12-16 2023-12-12 6K Inc. Spheroidal dehydrogenated metals and metal alloy particles
US11855278B2 (en) 2020-06-25 2023-12-26 6K, Inc. Microcomposite alloy structure
US11919071B2 (en) 2020-10-30 2024-03-05 6K Inc. Systems and methods for synthesis of spheroidized metal powders
US11963287B2 (en) 2021-09-20 2024-04-16 6K Inc. Systems, devices, and methods for starting plasma

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11839919B2 (en) 2015-12-16 2023-12-12 6K Inc. Spheroidal dehydrogenated metals and metal alloy particles
US11633785B2 (en) 2019-04-30 2023-04-25 6K Inc. Mechanically alloyed powder feedstock
US11717886B2 (en) 2019-11-18 2023-08-08 6K Inc. Unique feedstocks for spherical powders and methods of manufacturing
US11590568B2 (en) 2019-12-19 2023-02-28 6K Inc. Process for producing spheroidized powder from feedstock materials
US11855278B2 (en) 2020-06-25 2023-12-26 6K, Inc. Microcomposite alloy structure
US11919071B2 (en) 2020-10-30 2024-03-05 6K Inc. Systems and methods for synthesis of spheroidized metal powders
US11963287B2 (en) 2021-09-20 2024-04-16 6K Inc. Systems, devices, and methods for starting plasma
CN114361393A (en) * 2022-01-07 2022-04-15 山东大学 Method for simply preparing self-supporting silicon cathode and application of self-supporting silicon cathode in lithium/sodium battery
CN114361393B (en) * 2022-01-07 2023-08-15 山东大学 Method for preparing self-supporting silicon negative electrode and application of self-supporting silicon negative electrode in lithium/sodium battery
CN114695833A (en) * 2022-03-01 2022-07-01 北京化工大学 Lithium dendrite inhibition device, system and method for lithium metal battery negative electrode material

Similar Documents

Publication Publication Date Title
CN112421048A (en) Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost
WO2021128603A1 (en) Modified silicon monoxide material for use in negative electrode of lithium-ion battery and preparation method therefor
CN107275606B (en) Carbon-coated spinel lithium manganate nanocomposite and preparation method and application thereof
CN107732205B (en) Method for preparing sulfur-nitrogen co-doped carbon-coated nano flower-shaped lithium titanate composite negative electrode material
CN110299516B (en) Preparation method of carbon nanotube array loaded lithium titanate flexible electrode material
CN111048770B (en) Ternary doped silicon-based composite material and preparation method and application thereof
CN111009647B (en) Lithium borosilicate alloy cathode active material of lithium secondary battery, cathode, preparation and application thereof
CN110518213A (en) A kind of porous silicon-carbon nano tube compound material and its preparation method and application
CN107919477B (en) Application of mixed expanded graphite as negative electrode material of lithium ion battery
CN109244395B (en) Preparation method of in-situ nitrogen-doped carbon-coated lithium iron phosphate positive electrode material
CN111653734A (en) Ferrosilicon/carbon composite lithium ion battery cathode material and preparation method and application thereof
CN114388738B (en) Silicon-based anode material and preparation method and application thereof
CN114267841B (en) Preparation method and application of surface-fully-coated high-nickel single crystal ternary material
CN108923027B (en) Organic acid modified Si/TiO2Negative electrode material of/rGO @ C lithium ion battery and preparation method and application thereof
CN110233251A (en) A kind of preparation method and applications of porous silicon/carbon composite material
CN112289985B (en) C @ MgAl2O4Composite coating modified silicon-based negative electrode material and preparation method thereof
CN112133898B (en) Silicon-based negative electrode material and preparation method thereof
CN113130905A (en) Ultra-small cobalt sulfide nanosheet/carbon cloth composite material and preparation method thereof
CN111628153A (en) Novel lithium ion battery cathode material and preparation method thereof
CN111261857B (en) FePS for sodium ion battery3/NC composite negative electrode material, preparation method thereof and sodium ion battery
CN110265641A (en) A kind of lithium ion battery novel anode material
CN117374262B (en) Endogenous heterojunction anode material, preparation method thereof, negative electrode and lithium ion battery
CN114195111B (en) Method for co-producing porous micron silicon-carbon composite particles and aluminum dihydrogen phosphate by phosphoric acid method
Chen et al. Xanthan Gum as a Carbon Source for Preparation of Carbon-Silicon/Graphite Composite as Anode Materials for Lithium Ion Batteries
CN111900384B (en) Lithium-sulfur battery positive electrode material and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WW01 Invention patent application withdrawn after publication
WW01 Invention patent application withdrawn after publication

Application publication date: 20210226