CN110993949B - Cathode material with multiple coating structures, preparation method and application thereof - Google Patents
Cathode material with multiple coating structures, preparation method and application thereof Download PDFInfo
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- CN110993949B CN110993949B CN201911304384.5A CN201911304384A CN110993949B CN 110993949 B CN110993949 B CN 110993949B CN 201911304384 A CN201911304384 A CN 201911304384A CN 110993949 B CN110993949 B CN 110993949B
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- 238000000576 coating method Methods 0.000 title claims abstract description 55
- 239000011248 coating agent Substances 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 239000010406 cathode material Substances 0.000 title abstract description 13
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims abstract description 130
- 239000011247 coating layer Substances 0.000 claims abstract description 100
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 88
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 88
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 84
- 239000007773 negative electrode material Substances 0.000 claims abstract description 72
- 239000000463 material Substances 0.000 claims abstract description 63
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 60
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 60
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 60
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 50
- 229920000642 polymer Polymers 0.000 claims abstract description 42
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 37
- 239000007789 gas Substances 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 25
- 239000000377 silicon dioxide Substances 0.000 claims description 24
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 19
- 239000002002 slurry Substances 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 claims description 16
- 239000002253 acid Substances 0.000 claims description 12
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- 230000008569 process Effects 0.000 claims description 11
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Chemical compound [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 claims description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 9
- 239000002243 precursor Substances 0.000 claims description 9
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 claims description 8
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 claims description 8
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Inorganic materials [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 claims description 8
- 230000035484 reaction time Effects 0.000 claims description 8
- 238000001694 spray drying Methods 0.000 claims description 8
- 229910001416 lithium ion Inorganic materials 0.000 claims description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 6
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 6
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 6
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 6
- 229920002125 Sokalan® Polymers 0.000 claims description 5
- 239000010405 anode material Substances 0.000 claims description 5
- -1 lithium imide Chemical class 0.000 claims description 5
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 claims description 5
- 229910001947 lithium oxide Inorganic materials 0.000 claims description 5
- RBTVSNLYYIMMKS-UHFFFAOYSA-N tert-butyl 3-aminoazetidine-1-carboxylate;hydrochloride Chemical compound Cl.CC(C)(C)OC(=O)N1CC(N)C1 RBTVSNLYYIMMKS-UHFFFAOYSA-N 0.000 claims description 5
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 4
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 claims description 4
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 4
- 238000005229 chemical vapour deposition Methods 0.000 claims description 4
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 claims description 4
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- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 3
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 3
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 3
- REKWWOFUJAJBCL-UHFFFAOYSA-L dilithium;hydrogen phosphate Chemical compound [Li+].[Li+].OP([O-])([O-])=O REKWWOFUJAJBCL-UHFFFAOYSA-L 0.000 claims description 3
- 229910000103 lithium hydride Inorganic materials 0.000 claims description 3
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 3
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 3
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 2
- 229910000838 Al alloy Inorganic materials 0.000 claims description 2
- 239000012448 Lithium borohydride Substances 0.000 claims description 2
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- 239000004642 Polyimide Substances 0.000 claims description 2
- 238000004108 freeze drying Methods 0.000 claims description 2
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 claims description 2
- AFRJJFRNGGLMDW-UHFFFAOYSA-N lithium amide Chemical compound [Li+].[NH2-] AFRJJFRNGGLMDW-UHFFFAOYSA-N 0.000 claims description 2
- GCICAPWZNUIIDV-UHFFFAOYSA-N lithium magnesium Chemical compound [Li].[Mg] GCICAPWZNUIIDV-UHFFFAOYSA-N 0.000 claims description 2
- 229910001386 lithium phosphate Inorganic materials 0.000 claims description 2
- VVNXEADCOVSAER-UHFFFAOYSA-N lithium sodium Chemical compound [Li].[Na] VVNXEADCOVSAER-UHFFFAOYSA-N 0.000 claims description 2
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- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- BHZCMUVGYXEBMY-UHFFFAOYSA-N trilithium;azanide Chemical compound [Li+].[Li+].[Li+].[NH2-] BHZCMUVGYXEBMY-UHFFFAOYSA-N 0.000 claims description 2
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 claims description 2
- 230000001351 cycling effect Effects 0.000 abstract description 12
- 238000005336 cracking Methods 0.000 abstract description 5
- 239000005486 organic electrolyte Substances 0.000 abstract description 5
- 238000006479 redox reaction Methods 0.000 abstract description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 18
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 17
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 14
- 239000003792 electrolyte Substances 0.000 description 10
- 229910052786 argon Inorganic materials 0.000 description 9
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- 238000011065 in-situ storage Methods 0.000 description 8
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- 229910052710 silicon Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
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- PAZHGORSDKKUPI-UHFFFAOYSA-N lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 3
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- 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
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/523—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron for non-aqueous cells
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- 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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Abstract
The invention relates to a negative electrode material with a multiple coating structure, a preparation method and application thereof. The negative electrode material with the multiple coating structure comprises lithium-containing silicon oxide, and a lithium salt coating layer, a carbon coating layer and a polymer coating layer which are sequentially coated on the surface of the silicon oxide. The lithium salt coating layer of the negative electrode material effectively inhibits the volume expansion of the material, improves the surface ionic conductivity of the material, improves the cycling stability of the electrode and reduces the alkalinity of the material; the carbon coating layer of the cathode material improves the electronic conductivity of the surface of the material and the oxidation-reduction reaction rate of the surface of the material; the polymer coating layer of the cathode material improves the compatibility between the silicon monoxide and the organic electrolyte, limits the volume expansion of the material to a certain degree, avoids the cracking of the material and more effectively improves the cycling stability of the electrode.
Description
Technical Field
The invention belongs to the field of energy storage materials and electrochemistry, and particularly relates to a negative electrode material with a multiple cladding structure, and a preparation method and application thereof.
Background
The endurance mileage is a main factor which limits large-scale popularization and application of pure electric vehicles at present, and the improvement of the energy density of a power battery is the most effective scheme for solving the problem. The silicon material, particularly the silicon oxide, is considered to be the first choice of the negative electrode material in the chemical system of the high-energy-density power battery due to the high specific capacity (3-5 times of the graphite capacity). However, the currently mainstream silicon negative electrode product, namely, the silicon oxide negative electrode, has the disadvantages of low initial coulombic efficiency, poor cycle stability and the like, and the large-scale commercial application of the silicon negative electrode product is severely restricted.
First, in the presence of oxygen in the silicon monoxide, during the first charging process, lithium ions supplied from the positive electrode react with oxygen to form electrochemically inactive lithium silicate (Li)xSiyOz) And lithium oxide (Li)2O) rather than forming an electrochemically active lithium silicon alloy (Li)xSiy) The amount of reversible lithium ions is consumed, resulting in a first time lower coulombic efficiency. And the lower first efficiency directly influences the exertion of the positive electrode capacity, thereby reducing the improvement of the energy density of the battery. To solve this problem, a great deal of research and study has been conducted in both academia and industry, wherein the most effective method is to adopt a pre-doping process, directly intercalate metallic lithium or lithium salt into silica material through a high temperature reaction, and react with oxygen in advance to generate lithium oxide (Li)2O) and lithium silicate (Li)xSiyOz) And the consumption of positive lithium ions during circulation is reduced, so that the first coulombic efficiency is improved to a certain extent. However, due to the hydrolysis of lithium silicate and the existence of lithium oxide, the alkalinity of the negative electrode aqueous slurry is strong, and partial side reaction can occur with carboxyl-COOH in a mainstream silicon-carbon polymer binder (such as polyacrylic acid and the like), so that the performance of the binder and the long-term cycling stability of a battery cell are influenced; meanwhile, the slurry with strong alkalinity can react with the nano silicon particles in the silicon monoxide and release gas, so that the coating process is influenced, the activity of the nano silicon is reduced, and the capacity exertion of the material is reduced. Therefore, how to modify the surface of the high-first-effect silica and reduce the surface alkalinity has important significance on improving the cycle stability of the pole piece.
On the other hand, the large volume change of the silicon material can occur in the lithium intercalation process, the SEI film on the surface of the material is unstable due to the continuous volume change, the electrolyte continuously reacts with the newly generated surface, lithium salt and solvent are consumed, and the capacity of the battery is continuously reduced. The main components of the SEI film are various inorganic lithium salts and organic lithium salts, wherein the inorganic lithium salts have high mechanical strength and can effectively improve the cycling stability of the electrode, however, the inorganic lithium salts have poor compatibility in an organic electrolyte system, and the diffusion impedance of lithium ions between a negative electrode material and the electrolyte is increased, so that a coating layer with complementary functions is reasonably designed, and the SEI film is an important method for improving the cycling stability of the silicon negative electrode. The prior coating process for mass production of the silicon oxide mainly refers to a carbon coating process in artificial graphite processing, adopts asphalt to soften, coat and carbonize, thereby improving the surface stability of the silicon oxide material and simultaneously promoting partial electronic conductivity. However, since the particle size of the silica is small (the silica D50 is about 4 μm, and the artificial graphite D50>10 μm) and is slightly larger than the surface, and the surface characteristics of the silica are greatly different from those of the graphite material, a single asphalt carbon coating layer is difficult to uniformly cover the surface of the silica like graphite, and the interface stability of the material cannot be effectively improved. Meanwhile, the introduction of the simple carbon material does not obviously improve the ionic conductivity of the material and the interface compatibility between the material and the electrolyte.
CN108630925A discloses a preparation method of a graphene-coated silicon oxide negative electrode material, which comprises the following steps: 1) mixing the silica micropowder and the graphite micropowder, adding the mixture into the graphene oxide dispersion liquid, adding a dispersing agent, and performing ultrasonic dispersion treatment to form a suspension, namely graphene oxide; 2) carrying out spray drying and pelletizing on the suspension obtained in the step 1), and carrying out heat treatment at 500-800 ℃ in a reducing atmosphere to obtain the graphene-coated silica micropowder and graphite micropowder composite negative electrode material. However, the carbon layer of the negative electrode material obtained by the method has low coating strength and is easy to fall off.
CN108183200A discloses a preparation method for a lithium ion battery cathode material, which is characterized in that a micron-sized silicon oxide surface is coated with a layer of titanate, the titanate is uniformly mixed with a highly dispersed carbon nano tube water dispersion, water is removed to obtain a silicon oxide mixed powder mixed with a carbon nano tube, the silicon oxide mixed powder is added into a DMF solution containing polyacrylonitrile, the mass ratio of the mixed powder to PAN is (90-70) - (30-10), the DMF is removed by evaporation under reduced pressure after high-speed stirring for 1-10 hours, the obtained powder is sintered at the temperature of 250-400 ℃, and the silicon oxide cathode material is obtained by sintering, crushing and sieving at the temperature of 600-900 ℃. However, the surface groups of the material obtained by the method have self-difference, poor interface compatibility and poor polymer coating strength.
Therefore, there is a need in the art to develop a novel silicon monoxide negative electrode material, which has the advantages of uniform, complete and compact coating layer, high electrochemical reaction rate, simple preparation method, and industrial production.
Disclosure of Invention
Aiming at the problem that the silicon monoxide coating process in the prior art mainly refers to a carbon coating process (adopting asphalt to soften, coat and carbonize) in artificial graphite processing, a single asphalt carbon coating layer is difficult to uniformly cover the surface of the silicon monoxide, and the interface stability of the material cannot be effectively improved; meanwhile, the introduction of the simple carbon material has no obvious improvement on the ionic conductivity of the material and the interface compatibility between the material and the electrolyte, and the invention provides a negative electrode material with a multiple coating structure, a preparation method and application thereof. The cathode material with the multiple coating structure improves the cycling stability of the silicon oxide, improves the electronic conductivity and the electrochemical reaction rate of the surface of the material, limits the volume expansion of the material, and can effectively avoid the cracking of the material. The multiple coating structure is a structure that three coating layers are coated on the surface of the lithium-containing oxidized sub-silicon.
The invention aims to provide a negative electrode material with a multiple coating structure, which comprises lithium-containing silicon monoxide, and a lithium salt coating layer, a carbon coating layer and a polymer coating layer which are sequentially coated on the surface of the silicon monoxide.
According to the invention, the lithium salt coating layer is obtained by the in-situ reaction by utilizing the characteristic that the surface of the lithium-containing silicon oxide is alkaline, so that firstly, alkaline lithium on the surface of the material is reduced, the pH value of the negative electrode slurry is reduced, and the problems of binder failure and slurry bubbling caused by overhigh alkalinity of the slurry are solved; secondly, the in-situ inorganic lithium salt coating layer improves the ionic conductivity of the material surface and improves the characteristic of poor dynamics of the silicon monoxide negative electrode material; thirdly, the in-situ lithium salt coating layer is similar to the reduction product of the electrolyte in the SEI film, and meanwhile, the mechanical strength of the inorganic lithium salt is high, so that the volume expansion of the material and the generation of lithium dendrites can be effectively inhibited, and the cycling stability of the electrode is improved; fourth, compared with the lithium salt aqueous solution coating method and the solid-phase lithium salt blending method in the prior art, the in-situ gas phase reaction method has the advantage that the inorganic lithium salt coating layer is more complete and compact.
According to the conductive carbon coating layer of the negative electrode material, the characteristic that the inorganic lithium salt coating layer has multiple active sites is utilized, a small molecular carbon source is easier to adsorb and decompose into a nano carbon layer, and compared with a solid-phase asphalt coating method, the conductive carbon coating layer has the characteristics that the coating layer is uniform and controllable, and the like, and simultaneously, alkaline groups on the surface of high-efficiency oxidized silica are further coated, so that the hydrolysis reaction of a compound in slurry is limited, the problem of overhigh alkalinity of the slurry is solved, and the existence of the conductive carbon layer improves the electronic conductivity of the surface of the material, so that the oxidation-reduction reaction rate is improved.
According to the negative electrode material, the polymer coating layer utilizes the oxidizing groups on the surface of the conductive carbon coating layer, so that a better coating effect can be realized, the compatibility between the silicon oxide and the organic electrolyte is improved, the electrolyte can quickly infiltrate the surface of the material, and meanwhile, the polymer layer has elasticity after swelling, so that the volume expansion of the material is limited to a certain extent, the cracking of the material is avoided, and the cycling stability of the electrode is effectively improved.
Fig. 1 is a schematic structural diagram of the negative electrode material with a multiple coating structure provided by the present invention, in which 1 is a lithium-containing silicon monoxide, 2 is a lithium salt coating layer, 3 is a carbon coating layer, and 4 is a polymer coating layer.
Preferably, the size of the lithium-containing silica is 1 to 8 μm, for example, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 7 μm, or 7.5 μm.
Preferably, the thickness of the lithium salt coating layer is 0.1-20 nm, such as 0.5nm, 1nm, 2nm, 4nm, 5nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm or 18 nm.
Preferably, the lithium salt in the lithium salt coating layer includes Li2CO3、Li2SO4、LiNO3Any one or a combination of at least two of LiF and LiCl.
Preferably, in the negative electrode material having a multiple coating structure, the lithium salt coating layer is contained in an amount of 0.01 to 10 wt%, preferably 0.1 to 0.5 wt%, such as 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, or the like.
The lithium salt coating layer of the invention has a content of 0.01 wt% -10 wt%, and the content is too low to effectively improve the ionic conductivity and the interface strength; the content is too high, and the interface resistance of the material is increased.
Preferably, the thickness of the carbon coating layer is 0.1-20 nm, such as 0.5nm, 1nm, 2nm, 4nm, 5nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm or 18 nm.
Preferably, in the negative electrode material having a multiple coating structure, the content of the carbon coating layer is 0.01 wt% to 10 wt%, preferably 2 wt% to 4 wt%, such as 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, or 8 wt%, and the like.
The content of the carbon coating layer is 0.01 wt% -10 wt%, and the content is too low, so that the electronic conductivity of a material interface cannot be effectively improved; the content is too high, and the first coulombic efficiency of the negative electrode is reduced.
Preferably, the polymer coating layer has a thickness of 0.1 to 20nm, such as 0.5nm, 1nm, 2nm, 4nm, 5nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, and the like.
Preferably, in the negative electrode material having a multiple coating structure, the content of the polymer coating layer is 0.01 wt% to 10 wt%, preferably 0.5 wt% to 2 wt%, such as 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, or 8 wt%, and the like.
The polymer coating layer of the invention has the content of 0.01 wt% -10 wt%, and the wetting quality between the material and the electrolyte can not be effectively improved due to too low content; too high a content increases the interface resistance.
The second purpose of the present invention is to provide a method for preparing the negative electrode material with the multiple coating structure according to the first purpose, which comprises the following steps:
(1) reacting lithium-containing silicon monoxide with acid gas under the heating condition to obtain silicon monoxide coated with a lithium salt coating layer on the surface;
(2) carrying out carbon coating reaction on the silicon monoxide coated with the lithium salt coating layer on the surface in the step (1) and a gas carbon source to obtain a double-coated silicon monoxide material;
(3) and (3) mixing the double-coated silica material obtained in the step (2) with polymer slurry to obtain the negative electrode material with the multiple-coated structure.
The invention adopts a multiple coating process to carry out surface modification on the lithium-containing silicon monoxide, controls the surface alkalinity of the material and improves the electrochemical performance. Firstly, utilizing the characteristic that high-first-efficiency silicon monoxide is alkaline, carrying out in-situ reaction with acid gas to obtain a lithium salt coating layer, constructing an artificial SEI (solid electrolyte interphase) film, improving the interface strength and the ionic conductivity, and consuming partial alkaline lithium; on the basis, the lithium salt coating layer is generated, so that more active sites appear on the surface of the lithium-containing high-first-efficiency oxidized sub-silicon, and when the carbon coating layer is constructed by adopting a gas phase method, the small molecular carbon source can be better attached to and decomposed on the surface of the oxidized sub-silicon and can be grown into a compact coating layer, so that the alkalinity is further reduced, and the electronic conductivity of the material is improved; and finally, the polymer layer is further coated by utilizing the oxidation group on the surface of the carbon coating layer, so that the interface compatibility between the material and the electrolyte is improved, and meanwhile, the elasticity of the polymer can accommodate the volume expansion of the silicon oxide to a certain extent, so that the improvement of the cycle stability is realized.
The inorganic lithium salt coating layer is prepared by utilizing the in-situ reaction of acid gas on the basis of the alkalinity of the surface of the lithium-containing oxidized silica, and has the characteristics of more uniformity, controllable thickness and the like compared with a lithium salt aqueous solution coating method and a solid-phase lithium salt mixing method in the prior art; in the preparation process of the gas-phase conductive carbon coating, because of the existence of the in-situ lithium salt coating, a plurality of active sites are generated on the surface of the lithium-containing oxidized silicon, and small-molecule carbon source gas can be more easily adsorbed on the surface of the oxidized silicon to be decomposed to generate a nano carbon layer, so that the nano carbon layer has higher coating strength; in the preparation process of the polymer coating layer, the polymer and the carbon coating layer can be better combined by utilizing the surface oxidation group characteristic of the second conductive carbon coating layer, and in the prior art, the polymer is mostly directly contacted with the surface of the silicon oxide or inorganic lithium salt, and because the surface groups have self-difference, the interface compatibility is poor, and the strength of the polymer coating layer is poor.
Preferably, the process for preparing the lithium-containing silicon oxide of step (1) comprises: and carrying out heat treatment on the silicon monoxide precursor and a lithium-containing compound to obtain the lithium-containing silicon monoxide.
Different from the common silicon oxide material in the prior art, the lithium-containing silicon oxide has higher primary efficiency due to lithium pre-intercalation, but the aqueous slurry of the lithium-containing silicon oxide is alkaline, so that side reaction is more likely to occur, the cycle performance is poorer, and good surface modification is more needed to improve the stability.
Preferably, the structural formula of the silica precursor is SiOx0.5 of<x<1.2, e.g. 0.6, 0.7, 0.8, 0.9, 1 or 1.1 etc.
Preferably, the lithium-containing compound includes any one of or a combination of at least two of metallic lithium, a lithium sodium alloy, a lithium magnesium alloy, a lithium aluminum alloy, lithium oxide, lithium carbonate, lithium hydroxide, lithium sulfate, lithium nitrate, lithium fluoride, lithium phosphate, dilithium hydrogen phosphate, lithium chloride, lithium acetate, lithium hydride, lithium borohydride, lithium aluminum borohydride, lithium nitride, lithium amide, and lithium imide.
Preferably, the temperature of the heat treatment is 300 to 1200 ℃, for example 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃ or the like.
Preferably, the time of the heat treatment is 0.5-8 h, such as 1h, 2h, 3h, 4h, 5h, 6h or 7 h.
Preferably, the lithium-containing silica has a content of lithium element of 0.01 wt% to 20 wt%, preferably 2 wt% to 10 wt%, such as 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, or the like.
Preferably, the reaction is carried out under heating in the step (1) at a temperature of 200 to 800 ℃, for example, 250 ℃, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, or 750 ℃.
Preferably, the reaction time under the heating condition in the step (1) is 5-60 min, such as 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min or 55 min.
Preferably, the acid gas of step (1) comprises CO2、SO2、NO2、F2And Cl2Any one or a combination of at least two of them.
Preferably, the flow rate of the acid gas in step (1) is 10-100 sccm/min, such as 10sccm/min, 15sccm/min, 20sccm/min, 25sccm/min, 30sccm/min, 35sccm/min, 40sccm/min, 45sccm/min, 50sccm/min, 55sccm/min, 60sccm/min, 65sccm/min, 70sccm/min, 75sccm/min, 80sccm/min, 85sccm/min, 90sccm/min, or 95 sccm/min.
Preferably, the gaseous carbon source of step (2) comprises any one of natural gas, methane, ethane, propane, ethylene, propylene and acetylene or a combination of at least two thereof.
Preferably, the flow rate of the gaseous carbon source in step (2) is 30-100 sccm/min, such as 35sccm/min, 40sccm/min, 45sccm/min, 50sccm/min, 55sccm/min, 60sccm/min, 65sccm/min, 70sccm/min, 75sccm/min, 80sccm/min, 85sccm/min, 90sccm/min, or 95 sccm/min.
Preferably, the reaction time in the step (2) is 0.5-3 h, such as 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.5h, 1.6h, 1.8h, 2h, 2.4h, 2.5h, 2.6h or 2.8 h.
Preferably, the double-coated silica material in the step (2) is prepared by a chemical vapor deposition method.
Preferably, the polymer in the polymer slurry in step (3) comprises any one of styrene-butadiene rubber, acrylonitrile multipolymer, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyacrylic acid, lithium polyacrylate and polyimide or the combination of at least two of the two.
Preferably, the mass ratio of the double-coated silica material in the step (3) to the polymer in the polymer slurry is (5-10): 1, for example, 5.2:1, 5.5:1, 5.8:1, 6:1, 6.2:1, 6.5:1, 6.8:1, 7:1, 7.2:1, 7.5:1, 7.8:1, 8:1, 8.2:1, 8.4:1, or 9.8: 1.
Preferably, after the mixing in step (3), a spray drying and/or freeze drying process is further included.
As a preferred technical solution, the invention provides a preparation method of a negative electrode material with a multiple coating structure, which comprises the following steps:
(1) carrying out heat treatment on the silicon monoxide precursor and a lithium-containing compound at the temperature of 300-1200 ℃ for 0.5-8 h to obtain lithium-containing silicon monoxide with the lithium element content of 0.01-20 wt%;
(2) reacting the lithium-containing silicon monoxide with an acid gas at the temperature of 200-800 ℃ for 5-60 min, wherein the flow rate of the acid gas is 10-100 sccm/min, and obtaining silicon monoxide coated with a lithium salt coating layer on the surface;
(3) reacting the silicon monoxide coated with the lithium salt coating layer on the surface with a gas carbon source under the heating condition, wherein the flow rate of the gas carbon source is 30-100 sccm/min, the reaction time is 0.5-3 h, and preparing a double-coated silicon monoxide material by a chemical vapor deposition method;
(4) and mixing the double-coated silica material with polymer slurry, wherein the mass ratio of the double-coated silica material to the polymer in the polymer slurry is (5-10): 1, and performing spray drying to obtain the negative electrode material with the multiple-coating structure.
The invention also provides a negative pole piece, which comprises the negative pole material with the multiple coating structure.
The fourth purpose of the invention is to provide a lithium ion battery, which comprises the negative pole piece of the third purpose.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the invention, the characteristic that the surface of the lithium-containing silicon oxide is alkaline is utilized, and the lithium salt coating layer is obtained through in-situ reaction, so that the problems of binder failure and slurry bubbling caused by overhigh alkalinity of the slurry are solved; the ionic conductivity of the inorganic lithium salt is high, and the characteristic of poorer dynamics of the silicon monoxide negative electrode material is improved; the inorganic lithium salt coating layer is more complete and compact, the volume expansion of the material and the generation of lithium dendrites are effectively inhibited, and the cycling stability of the electrode is improved;
(2) the conductive carbon coating layer of the cathode material has the characteristics of uniformity, controllability and strong adhesive force, improves the electronic conductivity of the surface of the material, and improves the electrochemical reaction rate;
(3) the polymer coating layer improves the compatibility between the silicon monoxide and the organic electrolyte, limits the volume expansion of the material to a certain degree, avoids the cracking of the material and more effectively improves the cycling stability of the electrode;
(4) the invention adopts a multiple coating process to carry out surface modification on the lithium-containing high-efficiency silicon monoxide, controls the surface alkalinity of the material, improves the electrochemical performance, improves the interface compatibility between the material and the electrolyte and realizes the improvement of the cycle stability.
Drawings
Fig. 1 is a schematic structural diagram of a negative electrode material with a multiple-coating structure provided by the present invention, wherein 1 is a lithium-containing silicon monoxide, 2 is a lithium salt coating layer, 3 is a carbon coating layer, and 4 is a polymer coating layer.
Detailed Description
For the purpose of facilitating an understanding of the present invention, the following examples are set forth herein. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitation of the present invention.
Example 1
(1) Carrying out heat treatment on the 4 mu m of the silica precursor SiO and lithium hydride at 800 ℃ for 4h to obtain lithium-containing silica with the lithium element content of 8 wt%;
(2) taking 10g of the lithium-containing silicon monoxide powder, introducing argon (Ar) into a tubular atmosphere furnace at the flow rate of 100sccm/min, heating to 300 ℃ at the speed of 5 ℃/min, preserving heat, and introducing carbon dioxide (CO) at the flow rate of 50sccm/min2) Gas, after reaction for 20min, carbon dioxide (CO) was turned off2) Gas to obtain lithium-containing silicon monoxide with a lithium salt (lithium carbonate) coating layer;
(3) continuously introducing argon (Ar), heating to 920 ℃ at the speed of 5 ℃/min, and introducing acetylene (C) at the flow rate of 50sccm/min2H2) Gas, reaction time 1h, turn off acetylene gas (C)2H2) Continuously introducing argon (Ar) for reaction for 1h, closing heating, naturally cooling to room temperature, and sampling to obtain lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer;
(4) and (4) dissolving 2g of sodium carboxymethylcellulose in 50g of water, subsequently adding 6g of lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer obtained in the step (3), and preparing by adopting a spray drying method to realize polymer coating to obtain the cathode material with a multiple coating structure.
Example 2
The difference from example 1 is that in step (1), the content of lithium element in the lithium-containing silicon monoxide is 5 wt%, and in step (2), sulfur dioxide (SO) is controlled2) The flow rate of the gas was 30sccm/min, so that the content of the lithium sulfate coating layer in the obtained anode material having a multiple coating structure was 0.1 wt%.
Example 3
The difference from example 1 is that the content of lithium element in the lithium-containing silicon oxide of step (1) was 6.5 wt%, and carbon dioxide (CO) was controlled in step (2)2) The flow rate of the gas was 30sccm/min, so that the content of the lithium carbonate coating layer in the obtained negative electrode material having a multiple coating structure was 10 wt%.
Example 4
The difference from example 1 is that in step (1), the content of lithium element in the lithium-containing silicon monoxide was 2.5 wt%, and in step (2), sulfur dioxide (SO) was controlled2) The flow rate of the gas is 10sccm/min, so that the obtained multi-clad junction has multiple claddingIn the negative electrode material, the content of the lithium sulfate coating layer was 0.5 wt%.
Example 5
The difference from example 1 is that the content of lithium element in the lithium-containing siliconoxide in step (1) is 5 wt%, and carbon dioxide (CO) is controlled in step (2)2) The flow rate of the gas was 25sccm/min, so that the content of the lithium salt coating layer in the obtained negative electrode material having a multiple coating structure was 6 wt%.
Example 6
(1) Carrying out heat treatment on a 5-micron silicon oxide precursor SiO and dilithium hydrogen phosphate at the temperature of 600 ℃ for 3h to obtain lithium-containing silicon oxide with the content of lithium element of 0.1 wt%;
(2) 10g of the lithium-containing silicon monoxide powder is taken, argon (Ar) is introduced into a tubular atmosphere furnace at the flow rate of 100sccm/min, the temperature is raised to 400 ℃ at the speed of 5 ℃/min, the temperature is kept, and SO is introduced at the flow rate of 30sccm/min2Gas, after reaction lasts for 30min, SO is closed2Obtaining lithium-containing silicon monoxide with a lithium salt coating layer;
(3) continuously introducing argon (Ar), raising the temperature to 800 ℃ at the speed of 5 ℃/min, introducing ethylene gas at the flow of 50sccm/min, keeping the reaction time for 1.5h, closing the ethylene, continuously introducing argon (Ar) for reaction for 1h, closing the heating, naturally cooling to room temperature, and sampling to obtain lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer;
(4) and (4) dissolving 1g of polyacrylic acid in 50g of water, subsequently adding 5g of lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer obtained in the step (3), and preparing by adopting a spray drying method to realize polymer coating to obtain the cathode material with a multiple coating structure.
Example 7
(1) Carrying out heat treatment on a 4.5-micron silicon oxide precursor SiO and lithium sulfate at 800 ℃ for 2h to obtain lithium-containing silicon oxide with the lithium element content of 8 wt%;
(2) 10g of the lithium-containing silicon monoxide powder is taken, argon (Ar) is introduced into a tubular atmosphere furnace at the flow rate of 100sccm/min, the temperature is raised to 400 ℃ at the speed of 5 ℃/min, the temperature is kept, and NO is introduced at the flow rate of 80sccm/min2Gas, after reaction lasts for 10min, NO is turned off2Obtaining lithium-containing silicon monoxide with a lithium nitrate coating layer;
(3) continuously introducing argon (Ar), raising the temperature to 980 ℃ at the speed of 5 ℃/min, introducing ethane gas at the flow rate of 80sccm/min, continuing the reaction for 2h, closing ethane, continuously introducing argon (Ar) for reaction for 1h, closing heating, naturally cooling to room temperature, and sampling to obtain lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer;
(4) and (4) taking 1g of lithium carboxymethyl cellulose in 50g of water, subsequently adding 6g of lithium-containing silicon monoxide with a lithium salt coating layer and a carbon coating layer obtained in the step (3), and preparing by adopting a spray drying method to realize polymer coating to obtain the negative electrode material with a multiple coating structure.
Comparative example 1
Silicon monoxide (SiO) is adopted as the cathode material.
Comparative example 2
The lithium-containing silicon monoxide obtained in step (1) in example 1 was used as a negative electrode material.
Comparative example 3
The lithium-containing silicon monoxide having a lithium salt coating layer obtained in the step (2) in example 1 was used as a negative electrode material.
Comparative example 4
The lithium-containing silicon monoxide having a lithium salt coating layer and a carbon coating layer obtained in the step (3) in example 1 was used as a negative electrode material.
And (3) performance testing:
the negative electrode materials obtained in the examples and comparative examples of the present invention were assembled into a battery:
according to the anode material: conductive carbon black: mixing the PAA binder in a mass ratio of 8:1:1, mixing the mixture with dehydrated water as a solvent, coating the mixture on a copper foil, performing vacuum drying at 90 ℃, and rolling to obtain a negative pole piece; then the negative pole piece, the counter pole piece (metal lithium) and electrolyte (1mol/L LiPF)6EC: EMC: 1) and a separator were assembled into a battery.
The obtained battery is subjected to charge and discharge tests on a NEWARE BTS-5V/10mA type charge and discharge tester produced by New Wille electronics Limited company in Shenzhen under the environment of 25 +/-2 ℃, the charge and discharge voltage is 5 mV-2V, the current density is 200mA/g, the primary efficiency is tested to be 2V, and the 80% capacity retention rate cycle number is tested to be 80%; the surface pH of the anode materials obtained in the examples and comparative examples of the present invention were measured.
The test results are shown in table 1:
TABLE 1
As can be seen from table 1, the lithium-containing silica has a higher first efficiency than the general silica due to the pre-consumption of oxygen element; secondly, the lithium salt coating layer effectively inhibits the volume expansion of the material, improves the surface ionic conductivity of the material, improves the cycling stability of the electrode and reduces the alkalinity of the material; the carbon coating layer of the cathode material improves the electronic conductivity of the surface of the material and the oxidation-reduction reaction rate of the surface of the material; the polymer coating layer of the cathode material improves the compatibility between the silicon oxide and the organic electrolyte, limits the volume expansion of the material to a certain degree, avoids the cracking of the material and more effectively improves the cycling stability of the electrode.
The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of the raw materials of the product of the present invention, and the addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (33)
1. The negative electrode material with the multiple coating structure is characterized by comprising lithium-containing silicon oxide, and a lithium salt coating layer, a carbon coating layer and a polymer coating layer which are sequentially coated on the surface of the lithium-containing silicon oxide;
the preparation method of the anode material with the multiple coating structure comprises the following steps:
(1) reacting lithium-containing silicon oxide with acid gas under the heating condition to obtain lithium-containing silicon oxide with a lithium salt coating layer coated on the surface;
(2) carrying out carbon coating reaction on the lithium-containing silicon monoxide coated with the lithium salt coating layer on the surface in the step (1) and a gas carbon source to obtain a double-coated lithium-containing silicon monoxide material;
(3) and (3) mixing the double-coated lithium-containing silicon monoxide material obtained in the step (2) with polymer slurry to obtain the negative electrode material with a multiple-coated structure.
2. The negative electrode material of claim 1, wherein the size of the lithium-containing silicon monoxide is 1 to 8 μm.
3. The negative electrode material of claim 1, wherein the lithium salt coating layer has a thickness of 0.1 to 20 nm.
4. The negative electrode material of claim 1, wherein the lithium salt in the lithium salt coating layer comprises Li2CO3、Li2SO4、LiNO3Any one or a combination of at least two of LiF and LiCl.
5. The negative electrode material of claim 1, wherein the lithium salt coating layer is included in an amount of 0.01 to 10 wt% in the negative electrode material having the multiple coating structure.
6. The negative electrode material of claim 5, wherein the lithium salt coating layer is included in an amount of 0.1 to 0.5 wt% in the negative electrode material having the multiple coating structure.
7. The negative electrode material of claim 1 or 2, wherein the carbon coating layer has a thickness of 0.1 to 20 nm.
8. The negative electrode material of claim 1, wherein the content of the carbon coating layer in the negative electrode material having the multiple coating structure is 0.01 to 10 wt%.
9. The negative electrode material of claim 8, wherein the content of the carbon coating layer in the negative electrode material having the multiple coating structure is 2 to 4 wt%.
10. The negative electrode material of claim 1, wherein the polymer coating layer has a thickness of 0.1 to 20 nm.
11. The negative electrode material of claim 1, wherein the polymer coating layer is included in an amount of 0.01 to 10 wt% in the negative electrode material having the multiple coating structure.
12. The negative electrode material of claim 11, wherein the polymer coating layer is included in an amount of 0.5 to 2 wt% in the negative electrode material having the multiple coating structure.
13. The negative electrode material of claim 1, wherein the preparation process of the lithium-containing silicon monoxide in the step (1) comprises: and carrying out heat treatment on the silicon monoxide precursor and a lithium-containing substance to obtain the lithium-containing silicon monoxide.
14. The negative electrode material of claim 13, wherein the siliconoxide precursor has a structural formula of SiOx， 0.5<x<1.2。
15. The negative electrode material of claim 13, wherein the lithium-containing substance comprises any one of lithium metal, lithium sodium alloy, lithium magnesium alloy, lithium aluminum alloy, lithium oxide, lithium carbonate, lithium hydroxide, lithium sulfate, lithium nitrate, lithium fluoride, lithium phosphate, dilithium hydrogen phosphate, lithium chloride, lithium acetate, lithium hydride, lithium borohydride, lithium aluminum borohydride, lithium nitride, lithium amide, and lithium imide, or a combination of at least two thereof.
16. The negative electrode material of claim 13, wherein the heat treatment temperature is 300 to 1200 ℃.
17. The negative electrode material of claim 13, wherein the heat treatment time is 0.5 to 8 hours.
18. The negative electrode material according to claim 1, wherein the lithium-containing silicon monoxide contains 0.01 to 20 wt% of lithium element.
19. The negative electrode material of claim 18, wherein the lithium-containing silicon monoxide has a lithium element content of 2 to 10 wt%.
20. The negative electrode material according to claim 1, wherein the reaction temperature under heating in step (1) is 200 to 800 ℃.
21. The negative electrode material of claim 1, wherein the reaction time under heating in step (1) is 5 to 60 min.
22. The negative electrode material of claim 1, wherein the acid gas of step (1) comprises CO2、SO2、NO2、F2And Cl2Any one or a combination of at least two of them.
23. The negative electrode material according to claim 1, wherein the flow rate of the acid gas in the step (1) is 10 to 100 sccm/min.
24. The anode material of claim 1, wherein the gaseous carbon source of step (2) comprises any one of natural gas, methane, ethane, propane, ethylene, propylene, and acetylene, or a combination of at least two thereof.
25. The negative electrode material of claim 1, wherein the flow rate of the gaseous carbon source in the step (2) is 30 to 100 sccm/min.
26. The negative electrode material of claim 1, wherein the reaction time in the step (2) is 0.5-3 h.
27. The negative electrode material of claim 1, wherein the double-coated lithium-containing silica material in step (2) is prepared by chemical vapor deposition.
28. The negative electrode material of claim 1, wherein the polymer in the polymer slurry in the step (3) comprises any one of or a combination of at least two of styrene-butadiene rubber, acrylonitrile multipolymer, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyacrylic acid, lithium polyacrylate and polyimide.
29. The negative electrode material of claim 1, wherein the mass ratio of the double-coated lithium-containing silica material in the step (3) to the polymer in the polymer slurry is (5-10): 1.
30. The negative electrode material of claim 1, further comprising a spray drying and/or freeze drying process after the mixing in step (3).
31. The negative electrode material of claim 1, wherein the method comprises the steps of:
(1) carrying out heat treatment on the silicon monoxide precursor and a lithium-containing substance at the temperature of 300-1200 ℃ for 0.5-8 h to obtain lithium-containing silicon monoxide with the lithium element content of 0.01-20 wt%;
(2) reacting the lithium-containing silicon oxide with an acid gas at the temperature of 200-800 ℃ for 5-60 min, wherein the flow rate of the acid gas is 10-100 sccm/min, and obtaining the lithium-containing silicon oxide coated with a lithium salt coating layer;
(3) reacting the lithium-containing silicon monoxide coated with the lithium salt coating layer on the surface with a gas carbon source under the heating condition, wherein the flow rate of the gas carbon source is 30-100 sccm/min, and the reaction time is 0.5-3 h, and preparing a double-coated lithium-containing silicon monoxide material by a chemical vapor deposition method;
(4) and mixing the double-coated lithium-containing silicon monoxide material with polymer slurry, wherein the mass ratio of the double-coated lithium-containing silicon monoxide material to the polymer in the polymer slurry is (5-10): 1, and performing spray drying to obtain the negative electrode material with the multiple coating structure.
32. A negative electrode tab, characterized in that the negative electrode tab comprises the negative electrode material with the multiple-coating structure of any one of claims 1 to 31.
33. A lithium ion battery comprising the negative electrode tab of claim 32.
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| CN112310368B (en) * | 2020-10-16 | 2023-09-12 | 欣旺达电动汽车电池有限公司 | Negative electrode active material, preparation method and application thereof, and lithium ion battery |
| CN112310372B (en) * | 2020-10-26 | 2022-05-24 | 深圳市德方纳米科技股份有限公司 | Silicon-based negative electrode material and lithium ion battery |
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| CN113130872B (en) * | 2021-04-14 | 2022-12-13 | 贝特瑞新材料集团股份有限公司 | Composite material, preparation method thereof, negative electrode material, negative electrode plate and lithium ion battery |
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| CN114784237A (en) * | 2022-04-02 | 2022-07-22 | 合肥工业大学 | Silicon-based negative electrode, preparation method and application thereof |
| CN114672713B (en) | 2022-04-21 | 2022-09-16 | 胜华新能源科技(东营)有限公司 | Preparation method of lithium-containing metal silicon, lithium-containing SiO and application thereof |
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