CN114335490B - Preparation method of C@Cu@Si composite porous anode material of lithium ion battery - Google Patents
Preparation method of C@Cu@Si composite porous anode material of lithium ion battery Download PDFInfo
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- 239000002131 composite material Substances 0.000 title claims abstract description 70
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 39
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 239000010405 anode material Substances 0.000 title claims abstract description 15
- 239000000843 powder Substances 0.000 claims abstract description 72
- 238000000576 coating method Methods 0.000 claims abstract description 29
- 239000011248 coating agent Substances 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 28
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 24
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims abstract description 24
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000000758 substrate Substances 0.000 claims abstract description 19
- 239000007921 spray Substances 0.000 claims abstract description 18
- 239000007788 liquid Substances 0.000 claims abstract description 15
- WCCJDBZJUYKDBF-UHFFFAOYSA-N copper silicon Chemical compound [Si].[Cu] WCCJDBZJUYKDBF-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000000227 grinding Methods 0.000 claims abstract description 14
- 238000010288 cold spraying Methods 0.000 claims abstract description 13
- 230000008021 deposition Effects 0.000 claims abstract description 13
- 239000011863 silicon-based powder Substances 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000010426 asphalt Substances 0.000 claims abstract description 12
- 239000008367 deionised water Substances 0.000 claims abstract description 12
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 12
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000011889 copper foil Substances 0.000 claims abstract description 9
- 238000002347 injection Methods 0.000 claims abstract description 9
- 239000007924 injection Substances 0.000 claims abstract description 9
- 239000011259 mixed solution Substances 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims abstract description 6
- VUCPPBKKLBYOBY-UHFFFAOYSA-N [Si].[Cu].[C] Chemical compound [Si].[Cu].[C] VUCPPBKKLBYOBY-UHFFFAOYSA-N 0.000 claims abstract description 3
- 238000011049 filling Methods 0.000 claims abstract description 3
- 238000005507 spraying Methods 0.000 claims description 31
- 230000008569 process Effects 0.000 claims description 14
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 12
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 12
- -1 polypropylene Polymers 0.000 claims description 12
- 239000003792 electrolyte Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000000498 ball milling Methods 0.000 claims description 8
- 238000000889 atomisation Methods 0.000 claims description 7
- 239000000243 solution Substances 0.000 claims description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- 239000004743 Polypropylene Substances 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 229920001155 polypropylene Polymers 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 6
- 238000013329 compounding Methods 0.000 claims description 5
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 5
- 238000010000 carbonizing Methods 0.000 claims description 4
- 230000005484 gravity Effects 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 3
- 238000000713 high-energy ball milling Methods 0.000 claims description 3
- 239000002356 single layer Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 abstract description 8
- 239000010703 silicon Substances 0.000 abstract description 8
- 230000003116 impacting effect Effects 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 14
- 239000010949 copper Substances 0.000 description 12
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 10
- 239000007774 positive electrode material Substances 0.000 description 8
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 5
- 229910052786 argon Inorganic materials 0.000 description 5
- 230000014759 maintenance of location Effects 0.000 description 5
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 230000002441 reversible effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 3
- 238000009837 dry grinding Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007773 negative electrode material Substances 0.000 description 3
- 239000002153 silicon-carbon composite material Substances 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
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- 239000002253 acid Substances 0.000 description 1
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- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
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- 239000007772 electrode material Substances 0.000 description 1
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- 230000002708 enhancing effect Effects 0.000 description 1
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- 230000002687 intercalation Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
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- 229910021338 magnesium silicide Inorganic materials 0.000 description 1
- YTHCQFKNFVSQBC-UHFFFAOYSA-N magnesium silicide Chemical compound [Mg]=[Si]=[Mg] YTHCQFKNFVSQBC-UHFFFAOYSA-N 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
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- 239000002210 silicon-based material Substances 0.000 description 1
- 238000009718 spray deposition Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
Classifications
-
- 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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- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a preparation method of a lithium ion battery C@Cu@Si composite porous anode material, which comprises the steps of grinding and compositing silicon powder and copper powder to obtain copper-silicon composite powder; magnetically stirring asphalt powder, deionized water and tetrahydrofuran to obtain a uniform mixed solution; establishing a cold spraying system, taking copper foil as a substrate, configuring a pressure balancing device outside a powder feeder, and connecting the output end of an atomizer to the expansion section of a Laval nozzle; the method comprises the steps of adopting a double powder feeding mode, feeding copper-silicon composite powder into a powder feeder, filling a mixed solution into an atomizer through an injection pump, carrying the copper-silicon composite powder into a spray pipe through high-temperature high-pressure air flow, colliding with and wrapping liquid drops atomized by the atomizer, and simultaneously impacting the liquid drops to the surface of a substrate at a high speed to realize deposition to obtain a composite coating; the composite coating is carbonized after being dried to obtain the C@Cu@Si composite porous anode material of the lithium ion battery, and the double-layer coating structure of the carbon copper silicon can effectively relieve the volume expansion problem of the silicon-based anode.
Description
Technical Field
The invention belongs to the field of lithium ion batteries, and particularly relates to a preparation method of a C@Cu@Si composite porous negative electrode material of a lithium ion battery.
Background
The lithium ion battery is widely used in the fields of portable intelligent products such as mobile phones, unmanned aerial vehicles and the like due to the advantages of high specific capacity, long cycle life and the like, and the commercial demand of the lithium ion battery is increased along with the appearance and popularization of portable energy storage equipment.
Due to the fact that the theoretical capacity is too small, the traditional graphite cathode cannot meet the commercial requirements of the existing lithium ion battery. Silicon materials have gained attention in many alternative materials due to their high specific capacity (3580 mAh/g).
The technology for extracting the simple substance of silicon is mature in industry, however, silicon is used as the negative electrode of the lithium ion battery, huge volume change occurs in the process of working, namely lithium ion intercalation and deintercalation, the huge volume expansion can cause larger stress in the negative electrode, and finally, part of electrode materials are pulverized to cause the failure of the battery; in addition, the continuous volume expansion of silicon in each cycle process can lead the inside of the electrode not to form stable and uniform SEI film, and then the electrode can be broken, and then new SEI film is continuously generated, and the battery is also invalid until the electrolyte is consumed.
Researchers at home and abroad do a great deal of research on defects of lithium ion silicon-based cathodes, such as ways of nanocrystallizing particles, coating carbon, compounding with carbon materials or nonmetallic materials and the like aiming at materials; aiming at materials other than materials, novel adhesives are developed, electrolyte composition is improved, and current collectors are coated.
The high-energy ball milling method is different from the traditional composite process, has the advantages of low reaction temperature, uniform powder particle size, suitability for batch production and the like, and can be used for preparing superfine composite powder which cannot be prepared by a chemical method or a high-temperature method.
Cold gas dynamic spraying (cold spraying) technology is a surface deposition technology developed in recent years, spraying powder is sent into a Laval nozzle by a powder feeder, is accelerated by supersonic airflow and then is impacted on a substrate at a high speed, severe plastic deformation is generated, and the spraying powder is deposited on the substrate to form a coating.
Atomization is a technique of dispersing a liquid into numerous minute droplets by a special device. The liquid is sprayed out in a mist form by high-speed air flow or a pressure nozzle.
The existing preparation schemes of silicon-carbon composite, silicon-copper composite and the like have the defects of high production cost, low efficiency, low bonding strength, complex process, unfavorable mass production and the like.
The invention discloses a preparation method of a porous silicon-carbon composite material, as in Chinese patent application number CN201610164963.4, which comprises the following specific steps: placing magnesium silicide powder in a CO2/Ar mixed atmosphere, performing heat treatment at 700-900 ℃, and then performing acid washing and post-treatment to obtain the porous silicon-carbon composite material; in the CO2/Ar mixed atmosphere, the volume fraction of CO2 is 10-90%. The scheme has the advantages that the heat treatment time is about 10-20 h, the pickling adopts hydrochloric acid with the concentration of 0.5-5 mol/L, the treatment time is 2-10 h, the scheme also comprises the processes of water washing, product centrifugation, vacuum drying and the like, the whole scheme has the advantages of complex process, more required equipment, time and energy consumption, high cost and obvious adverse effect on industrial production.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a preparation method of a C@Cu@Si composite porous negative electrode material of a lithium ion battery. A porous structure is constructed by adopting a series of physical methods, so that the volume expansion of the silicon-based negative electrode of the lithium ion battery is provided with a receivable space, and the conductivity is enhanced.
In order to solve the technical problems, the invention adopts the following technical scheme:
the preparation method of the composite porous anode material of the lithium ion battery C@Cu@Si comprises the following steps:
(1) Mixing silicon powder and copper powder in proportion, and then adopting a high-energy ball milling method to carry out grinding and compounding to obtain copper-silicon composite powder;
(2) Mixing asphalt powder, deionized water and tetrahydrofuran in proportion, and magnetically stirring to obtain a uniform mixed solution;
(3) A cold spraying system is established, a pre-cleaned copper foil is used as a substrate, a pressure balancing device is arranged outside the powder feeder to realize gravity powder feeding, the fed powder is driven by high-temperature and high-pressure air flow and is fed into a Laval nozzle, and the output end of an atomizer is connected to an expansion section of the Laval nozzle;
(4) The method comprises the steps of adopting a double powder feeding mode, feeding the copper-silicon composite powder into a powder feeder, filling a mixed solution into an atomizer through an injection pump, carrying the copper-silicon composite powder fed by gravity into a Laval nozzle through high-temperature high-pressure air flow in the spraying process, passing through a throat to reach a nozzle expansion section, colliding with and wrapping liquid drops atomized by the atomizer, and striking the surface of a substrate at a high speed to realize deposition to obtain a composite coating;
(5) And (3) drying the composite coating and carbonizing to obtain the carbon copper silicon composite porous anode of the lithium ion battery.
Further, in the step (1), the volume ratio of the copper powder to the silicon powder is 1 (1-2).
Further, in the step (1), the average grain diameter of the silicon powder is 500nm-50 mu m, and the average grain diameter of the copper powder is 500nm-30 mu m.
Further, in the step (1), the rotating speed of the ball mill ranges from 200rpm to 600rpm, the ball-material ratio is 10:1, and the ball milling time is 4 hours to 24 hours.
Further, the asphalt powder, deionized water and tetrahydrofuran in the step (2) are mixed at room temperature and magnetically stirred.
Further, in the step (2), the volume ratio of the asphalt powder to the deionized water to the tetrahydrofuran is 1: (0.5-2): 1.
further, in the step (3), the diameter of a spray hole of the atomizer is 0.1-0.5mm, the diameter of a joint of an output end of the atomizer and the Laval nozzle is 0.1-20mm, the diameter of a hole of the powder feeder is 0.1-0.5mm, and the diameter of a powder feeding pipe is 0.1-20mm.
Further, the Laval nozzle, the powder feeder, the powder feeding pipe, the atomizer and the output end of the atomizer in the step (3) are made of stainless steel, so that the tightness in the whole cold spraying process is ensured.
Further, in the step (3), the output end position of the atomizer is 1/3-2/3 of the length of the expansion section of the whole spray pipe.
Further, in the step (3), the flow rate of the atomizer is 0.01-0.3L/min, the atomization pressure is 1-10MPa, the flow rate of the powder feeder is 10-150g/min, the high-temperature high-pressure air flow pressure, namely the cold spraying nitrogen air flow pressure, is 1-10MPa, the atomization pressure is generally required to be higher than the main air flow pressure, the spraying temperature is 100-1000 ℃, the pulse frequency of the stepping motor is 100-3000Hz, the distance between the spray pipe and the substrate is 1-50mm, the spraying path is in a shape like a Chinese character 'zhu', the spraying scanning speed is 0.1-1m/s, the spraying pass range is 1-5 times, and the accelerating gas used in the spraying process is nitrogen.
Further, in the step (4), the atomization amount of the atomizer is controlled by adjusting the injection pump pressure, the powder feeding amount of the powder feeder is controlled by adjusting the pulse frequency of the stepping motor, and after the copper-silicon composite powder fed by the powder feeder and the liquid drops atomized by the atomizer are impacted and mixed in the spray pipe expansion section, the main air flow of the cold spraying system accelerates, the spraying direction is downward and vertical to the copper foil substrate horizontally placed, and the deposition thickness is 0.1-1mm, so that the composite coating is prepared.
Further, in the step (5), the composite coating is dried for 1 to 12 hours at 70 to 150 ℃. And then transferring the mixture into a nitrogen atmosphere, heating to 500-1500 ℃ at a heating rate of 5 ℃/min, and carbonizing for 1-24h to obtain the C@Cu@Si composite porous anode material.
The preparation method disclosed by the invention is used for preparing the C@Cu@Si composite porous anode material: the method comprises the steps of taking a metal lithium sheet as a counter electrode, taking single-layer polypropylene as a diaphragm (Celgard 2300), taking a mixed solution of 1mol/L lithium hexafluorophosphate solution, ethylene Carbonate (EC) and diethyl carbonate (DEC) 1:1 (volume ratio) solvent as an electrolyte, taking the C@Cu@Si composite porous anode material as an anode (for a half cell, the C@Cu@Si composite porous anode material is actually used as a positive electrode), and assembling the half cell.
Further, it is required that the mounting of the half-cells is performed in an argon glove box.
Further, the assembly process of the half cell is as follows: firstly, placing a negative electrode shell on an insulating table top, placing a gasket and a metal lithium sheet in sequence at the center of the negative electrode shell by using insulating tweezers, then performing flattening treatment on the metal lithium sheet by using a tabletting mold, then taking a proper amount of electrolyte by using a liquid transfer device to add to the surface of the lithium sheet, placing a diaphragm on the center of the electrolyte, placing a proper amount of electrolyte on the surface of the diaphragm by using the liquid transfer device, and placing the negative electrode sheet, the gasket, the elastic sheet and the positive electrode shell on the diaphragm in sequence.
According to the invention, the volume ratio of silicon powder to copper powder in the experimental preparation process is adjusted to prepare copper-silicon composite powder with different structures and sizes. The C@Cu@Si composite coating with different element concentrations and porosities is prepared by adjusting the dissolution proportion of asphalt powder, deionized water and tetrahydrofuran and performing atomization and cold spray deposition. And C@Cu@Si composite coatings with different bonding strength and deposition efficiency are prepared by adjusting the positions of the liquid drop output ends of the atomizers.
The invention has the beneficial effects that:
1. the metal copper with better conductivity is selected for ball milling and compounding, which is favorable for alleviating volume effect and enhancing electronic conductivity, and physical technology is adopted to improve experimental controllability.
2. The copper selected in the invention is equivalent to a binder, and is used for realizing good connection inside the silicon-based negative electrode, organic solution is doped and carbonization treatment is carried out, so that a stable conductive network can be constructed, a porous structure is formed, a lithium ion transmission channel is increased, and the ion conductivity and the electron conductivity are improved.
3. The invention can realize the efficient compounding of the copper-silicon composite powder and the carbon-based material, and prepare the composite coating with uniformly dispersed elements and controllable thickness.
4. The prepared lithium ion battery C@Cu@Si composite porous negative electrode has the advantages of excellent conductivity, high first coulomb efficiency, good cycle performance and the like.
5. The lithium ion battery prepared by the invention has the advantages of excellent conductivity, high initial coulomb efficiency, good cycle performance and the like because the lithium ion battery prepared by the invention comprises the C@Cu@Si composite porous negative electrode.
6. The preparation method is simple and easy to operate, reduces the cost while relieving the volume expansion of silicon, improves the efficiency, and has higher feasibility of large-scale production.
Drawings
Fig. 1 is a process flow diagram for preparing a composite porous anode of lithium ion battery c@cu@si according to the invention.
Fig. 2 is a schematic view of the internal structure of the half cell according to the present invention.
Fig. 3 shows the results of electrochemical cycling tests of the electrode prepared by spraying after ball milling of Cu: si=1:1 (volume ratio) for 24 hours.
Fig. 4 shows EIS test results after 200 cycles of spray-prepared electrodes after 24h ball milling of Cu: si=1:1 (volume ratio).
Detailed Description
The invention will be described in detail with reference to specific examples. It should be understood that the following examples are intended to illustrate the present invention and not to limit the scope of the invention, and that those skilled in the art can make various insubstantial modifications and adaptations in light of the above disclosure.
Example 1
The metal lithium sheet is used as a negative electrode active material of the lithium ion battery, and the C@Cu@Si composite porous negative electrode prepared in the embodiment is used as a positive electrode active material of the lithium ion battery. The specific implementation steps are as follows: 5 mu m copper powder and 10 mu m silicon powder are weighed according to a volume ratio of 1:1 (17.8 g and 4.6g respectively), mixed and placed into a grinding tank, zirconium dioxide is used as grinding balls, the ball material ratio is 10:1, the rotating speed of a ball mill is 300rpm, the continuous forward dry grinding is carried out for 12 hours, the powder is added into a powder feeder, asphalt powder, deionized water and tetrahydrofuran are mixed according to a volume ratio of 1:0.5:1, the powder is magnetically stirred for 1 hour, the powder is added into a syringe, the temperature of a heater of a cold spraying system is regulated to be kept at 300 ℃, the spraying pressure is kept at 2MPa, the injection pump pressure (namely the atomizer pressure) is kept at 2.5MPa, the flow rate of the atomizer is 0.01L/min, the flow rate of the powder feeder is 10g/min, the liquid drop output end of the atomizer is connected to the expansion section 1/3 of a spray pipe, the spray pipe is 30mm away from a substrate, the scanning speed of the spray pipe is kept at 0.1m/s, the pulse frequency of a stepping motor is kept at 500Hz, the thickness of the substrate is 0.2mm, the deposition thickness of the copper foil is 2, the deposition thickness of the composite coating is kept at 0.1 ℃ and the deposition thickness is kept at 70 mm, the composite coating is prepared, the composite coating is dried at 70 ℃ and the temperature is heated for 3 hours under the heating rate of nitrogen gas of the negative electrode under the condition of 900 h, and the condition after the composite coating is heated to be heated for 900 hours. The half-cell was assembled in the order described in an argon glove box with the positive electrode material, a polypropylene microporous separator (Celgard 2300), an electrolyte mixed with 1mol/L lithium hexafluorophosphate solution and 1:1 (volume ratio) of Ethylene Carbonate (EC) and diethyl carbonate (DEC) solvents. The lithium ion battery of the composite porous negative electrode is charged for 2 hours at room temperature under the constant current of 0.05C, is discharged for the first time under the constant current of 0.5C, and is tested for coulombic efficiency of the first cycle and the first reversible cycle and capacity retention rate after 500 cycles.
Example 2
This embodiment differs from embodiment 1 only in that: the ball mill rotation speed was 500rpm.
Example 3
This embodiment differs from embodiment 1 only in that: the volume ratio of the copper powder to the silicon powder is 1:2.
example 4
This embodiment differs from embodiment 1 only in that: and continuously forward ball milling for 24 hours.
Example 5
This embodiment differs from embodiment 1 only in that: the volume ratio of the asphalt powder to the deionized water to the tetrahydrofuran is 1:1:1.
Example 6
This embodiment differs from embodiment 1 only in that: the spraying temperature was 500 ℃.
Example 7
This embodiment differs from embodiment 1 only in that: the nozzle scanning speed is 0.2m/s.
Example 8
This embodiment differs from embodiment 1 only in that: the pressure of the injection pump and the powder feeder are both kept at 3MPa.
Example 9
This embodiment differs from embodiment 1 only in that: the first charge was carried out for 2h at a constant current of 0.5C.
Example 10
This embodiment differs from embodiment 1 only in that: the first discharge was performed at a constant current of 1C.
Example 11
The C@Cu@Si composite porous negative electrode prepared by the method is used as a positive electrode active material of a lithium ion battery. The specific implementation steps are as follows: mixing 500 mu m copper powder and 30 mu m silicon powder according to a volume ratio of 1:1, putting the mixture into a grinding tank, taking zirconium dioxide as grinding balls, continuously and positively grinding the mixture for 10 hours at a ball mill rotating speed of 600rpm, adding the mixture into a powder feeder, mixing asphalt powder, deionized water and tetrahydrofuran according to a volume ratio of 1:2:1, magnetically stirring the mixture for 1 hour, adding the mixture into a syringe, adjusting the temperature of a heater of a cold spraying system to be 300 ℃, keeping the spraying pressure to be 5MPa, keeping the injection pump pressure (namely the atomizer pressure) to be 10MPa, enabling the flow rate of the atomizer to be 0.3L/min, enabling the flow rate of the powder feeder to be 150g/min, enabling the liquid drop output end of the atomizer to be connected to a position of a spray pipe expansion section 1/3, enabling a spray nozzle to be 30mm away from a substrate, enabling the spray pipe scanning speed to be kept to be 1m/s, enabling the pulse frequency of a stepping motor to be kept at 100Hz, enabling the thickness of the substrate to be 0.2mm, enabling the deposition thickness to be 1mm, carrying out preparation of a composite coating, drying the composite coating at 150 ℃ for 1 hour, moving the copper foil into a nitrogen atmosphere, and heating the anode material to be obtained at a speed of 1200 ℃ for 6 hours. The half-cell was assembled in the order described in an argon glove box with the positive electrode material, a polypropylene microporous separator (Celgard 2300), an electrolyte mixed with 1mol/L lithium hexafluorophosphate solution and 1:1 (volume ratio) of Ethylene Carbonate (EC) and diethyl carbonate (DEC) solvents. The lithium ion battery of the composite porous negative electrode is charged for 2 hours at room temperature under the constant current of 0.05C, is discharged for the first time under the constant current of 0.5C, and is tested for coulombic efficiency of the first cycle and the first reversible cycle and capacity retention rate after 500 cycles.
Example 12
The C@Cu@Si composite porous negative electrode prepared by the method is used as a positive electrode active material of a lithium ion battery. The specific implementation steps are as follows: mixing 500nm copper powder and 500nm silicon powder according to a volume ratio of 1:2, putting the mixture into a grinding tank, taking zirconium dioxide as grinding balls, continuously and positively grinding the zirconium dioxide as the grinding balls at a ball material ratio of 10:1, carrying out dry grinding for 12 hours at a ball mill rotating speed of 200rpm, adding the mixture into a powder feeder, mixing asphalt powder, deionized water and tetrahydrofuran according to a volume ratio of 1:0.5:1, magnetically stirring the mixture for 1 hour, adding the mixture into a syringe, regulating the temperature of a heater of a cold spraying system to be 500 ℃, keeping the spraying pressure to be 10MPa, keeping the injection pump pressure (namely the atomizer pressure) to be 10MPa, keeping the flow rate of the atomizer to be 0.2L/min, keeping the flow rate of the powder feeder to be 150g/min, connecting the liquid drop output end of the atomizer to the position of a spray pipe expansion section 1/3, keeping the spray pipe scanning speed to be 0.1m/s at a pulse frequency of 500Hz, keeping the thickness of a copper foil substrate to be 0.2mm, keeping the deposition thickness to be 0.5mm, carrying out composite coating preparation, drying the composite coating at 100 ℃ for 5 hours, and then moving the composite coating into nitrogen atmosphere at a heating rate of 5 ℃ to be 24 ℃ for 24 hours. The half-cell was assembled in the order described in an argon glove box with the positive electrode material, a polypropylene microporous separator (Celgard 2300), an electrolyte mixed with 1mol/L lithium hexafluorophosphate solution and 1:1 (volume ratio) of Ethylene Carbonate (EC) and diethyl carbonate (DEC) solvents. The lithium ion battery of the composite porous negative electrode is charged for 2 hours at room temperature under the constant current of 0.05C, is discharged for the first time under the constant current of 0.5C, and is tested for coulombic efficiency of the first cycle and the first reversible cycle and capacity retention rate after 500 cycles.
Example 13
The C@Cu@Si composite porous negative electrode prepared by the method is used as a positive electrode active material of a lithium ion battery. The specific implementation steps are as follows: mixing copper powder with the volume ratio of 1 mu m and silicon powder with the volume ratio of 1:1, putting the mixture into a grinding tank, taking zirconium dioxide as grinding balls, taking the ball material ratio of 10:1, carrying out continuous positive rotation dry grinding for 4 hours at the rotating speed of 400rpm of a ball mill, adding the mixture into a powder feeder, mixing asphalt powder, deionized water and tetrahydrofuran with the volume ratio of 1:1:1, magnetically stirring for 1 hour, adding the mixture into a syringe, adjusting the temperature of a heater of a cold spraying system to be 1000 ℃, keeping the spraying pressure to be 1MPa, keeping the injection pump pressure (namely the pressure of an atomizer) to be 1MPa, keeping the flow rate of the atomizer to be 0.05L/min, keeping the flow rate of the powder feeder to be 50g/min, connecting the liquid drop output end of the atomizer to the position of a spray pipe expansion section 1/3, keeping the spray pipe scanning speed to be 0.1m/s at the distance of a nozzle from a substrate of 30mm, keeping the pulse frequency of a stepping motor to be 500Hz, keeping the thickness of a copper foil substrate to be 0.2mm, keeping the deposition thickness to be 0.5mm, carrying out preparation of a composite coating, drying the composite coating at the temperature of 90 ℃ for 10 hours, and then moving the composite coating into nitrogen atmosphere at the temperature of 5 ℃ to be heated to a heating rate of 1500 ℃ for 1 h. The half-cell was assembled in the order described in an argon glove box with the positive electrode material, a polypropylene microporous separator (Celgard 2300), an electrolyte mixed with 1mol/L lithium hexafluorophosphate solution and 1:1 (volume ratio) of Ethylene Carbonate (EC) and diethyl carbonate (DEC) solvents. The lithium ion battery of the composite porous negative electrode is charged for 2 hours at room temperature under the constant current of 0.05C, is discharged for the first time under the constant current of 0.5C, and is tested for coulombic efficiency of the first cycle and the first reversible cycle and capacity retention rate after 500 cycles.
Fig. 3 shows the results of electrochemical cycling tests of the electrode prepared by spraying after ball milling of Cu: si=1:1 (volume ratio) for 24 hours. The circulation mode is constant current charge and discharge, the first 3 times of 100mA/g, the last 197 times of 500mA/g and the circulation time of 200 times. The initial specific capacities are greatly different, and the initial specific capacities of the Cu@Si-spraying electrodes and the C@Cu@Si-spraying electrodes are respectively 76 mAh.g -1 ,880 mAh·g -1 After 200 times of circulation, the specific capacity of the Cu@Si-spraying electrode is only 9 mAh.g -1 And the specific capacity of the C@Cu@Si-spraying electrode is up to 186 mAh.g -1 . The capacity retention rates of the Cu@Si-spray electrode cycle 1,2,200 and C@Cu@Si-spray electrode cycle 1,2,200 were respectively 68.4%,81.5%,11.8% and 43.9%,40.9% and 21.1%, respectively.
Fig. 4 shows EIS test results after 200 cycles of spray-prepared electrodes after 24h ball milling of Cu: si=1:1 (volume ratio). In conjunction with analysis of cycle performance, although Cu was incorporated for the purpose of designThe conductive network is counted to enhance conductivity, but then C is incorporated to actually construct a good conductive network. After 200 times of circulation, the lithium ion diffusion coefficient of the Cu@Si-spraying electrode is 3.98X10 -17 cm² s -1 The diffusion coefficient of lithium ions of the C@Cu@Si-sprayed electrode is 2.22×10 -15 cm² s -1 The diffusion coefficient of lithium ions of the C@Cu@Si-spraying electrode is far greater than that of the Cu@Si-spraying electrode, and the fact that the complete lithium ion transportation channel is constructed by adding the C is proved, so that the transfer of lithium ions in the electrode can be accelerated, and the electrode shows higher electrochemical activity.
The above describes the research methods, basic content, and beneficial effects of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the foregoing embodiments, which are described in the foregoing embodiments and description merely illustrate the principles of the invention, and that various modifications and improvements may be made therein without departing from the spirit and scope of the invention, which is defined by the claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (9)
1. A preparation method of a lithium ion battery C@Cu@Si composite porous anode material is characterized by comprising the following steps of: comprising the following steps:
(1) Mixing silicon powder and copper powder in proportion, and then adopting a high-energy ball milling method to carry out grinding and compounding to obtain copper-silicon composite powder;
(2) Mixing asphalt powder, deionized water and tetrahydrofuran in proportion at room temperature, and magnetically stirring to obtain a uniform mixed solution;
(3) A cold spraying system is established, a pre-cleaned copper foil is used as a substrate, a pressure balancing device is arranged outside the powder feeder to realize gravity powder feeding, the fed powder is driven by high-temperature and high-pressure air flow and is fed into a Laval nozzle, and the output end of an atomizer is connected to an expansion section of the Laval nozzle;
(4) Introducing the copper-silicon composite powder obtained in the step (1) into a powder feeder in a double powder feeding mode, filling the mixed solution obtained in the step (2) into an atomizer through a syringe pump, carrying the copper-silicon composite powder fed by gravity into a Laval nozzle through high-temperature high-pressure air flow in the spraying process, passing through the throat part of the Laval nozzle to reach a nozzle expansion section, and colliding with and wrapping liquid drops atomized by the atomizer, and striking the surface of a substrate at a high speed to realize deposition to obtain a composite coating;
(5) And (3) carbonizing the composite coating obtained in the step (4) after drying treatment to obtain the composite porous anode material of the lithium ion battery C@Cu@Si.
2. The method of manufacturing according to claim 1, characterized in that: the volume ratio of the copper powder to the silicon powder in the step (1) is 1 (1-2); the average grain diameter of the silicon powder is 500nm-50 mu m, and the average grain diameter of the copper powder is 500nm-30 mu m.
3. The method of manufacturing according to claim 1, characterized in that: the rotating speed range of the ball mill in the step (1) is 200-600rpm, the ball-material ratio is 10:1, and the ball milling time is 4-24 h.
4. The method of manufacturing according to claim 1, characterized in that: in the step (2), the volume ratio of the asphalt powder to the deionized water to the tetrahydrofuran is 1 (0.5-2): 1.
5. The method of manufacturing according to claim 1, characterized in that: the diameter of the spray hole of the atomizer in the step (3) is 0.1-0.5mm, the diameter of the joint of the output end of the atomizer and the Laval nozzle is 0.1-20mm, the diameter of the orifice of the powder feeder is 0.1-0.5mm, and the diameter of the powder feeding pipe is 0.1-20mm, and the Laval nozzle, the powder feeder, the powder feeding pipe, the atomizer and the output end of the atomizer are all made of stainless steel, so that the tightness in the whole cold spraying process is ensured; the joint of the output end of the atomizer and the Laval nozzle in the step (3) is positioned at 1/3-2/3 of the length of the expansion section of the whole Laval nozzle.
6. The method of manufacturing according to claim 1, characterized in that: the flow rate of the atomizer in the step (4) is 0.01-0.3L/min, the atomization pressure is 1-10MPa, the flow rate of the powder feeder is 10-150g/min, the high-temperature high-pressure air flow adopts nitrogen, the high-temperature high-pressure air flow pressure is 1-10MPa, the spraying temperature is 100-1000 ℃, the pulse frequency of the stepping motor is 100-3000Hz, the distance between the Laval nozzle and the substrate is 1-50mm, the spraying path is in an arc shape, the spraying scanning speed is 0.1-1m/s, the spraying pass range is 1-5 times, and the accelerating gas used in the spraying process is nitrogen.
7. The method of manufacturing according to claim 1, characterized in that: in the step (4), the atomization amount of the atomizer is controlled by adjusting the pressure of the injection pump, the powder feeding amount of the powder feeder is controlled by adjusting the pulse frequency of the stepping motor, and after the copper-silicon composite powder fed by the powder feeder and liquid drops atomized by the atomizer are impacted and mixed in the expansion section of the Laval nozzle, the main air flow of the cold spraying system accelerates, the spraying direction is downward vertical to the horizontally placed copper foil substrate, and the deposition thickness is 0.1-1mm, so that the composite coating is prepared.
8. The method of manufacturing according to claim 1, characterized in that: and (3) drying the composite coating in the step (5) at 70-150 ℃ for 1-12 hours, then transferring the composite coating into a nitrogen atmosphere, heating to 500-1500 ℃ at a heating rate of 5 ℃/min, and carbonizing for 1-24 hours to obtain the composite porous anode material of the lithium ion battery C@Cu@Si.
9. The application of the carbon copper silicon composite porous anode material of the lithium ion battery prepared by the preparation method according to any one of claims 1 to 8, which is characterized in that: the method comprises the steps of taking a metal lithium sheet as a counter electrode, taking single-layer polypropylene as a diaphragm (Celgard 2300), taking a mixed solution of 1mol/L lithium hexafluorophosphate solution, ethylene Carbonate (EC) and diethyl carbonate (DEC) 1:1 (volume ratio) solvent as an electrolyte, and taking the C@Cu@Si composite porous anode material as an anode to assemble a half battery.
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