CN114914444B - Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery - Google Patents
Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery Download PDFInfo
- Publication number
- CN114914444B CN114914444B CN202110184727.XA CN202110184727A CN114914444B CN 114914444 B CN114914444 B CN 114914444B CN 202110184727 A CN202110184727 A CN 202110184727A CN 114914444 B CN114914444 B CN 114914444B
- Authority
- CN
- China
- Prior art keywords
- silicon
- binder
- conductive agent
- particles
- mixed solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 title claims abstract description 49
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 24
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 24
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 239000002245 particle Substances 0.000 claims abstract description 97
- 239000006258 conductive agent Substances 0.000 claims abstract description 90
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 89
- 239000011230 binding agent Substances 0.000 claims abstract description 60
- 239000011259 mixed solution Substances 0.000 claims abstract description 60
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 45
- 239000010439 graphite Substances 0.000 claims abstract description 45
- 239000000243 solution Substances 0.000 claims abstract description 36
- 238000002156 mixing Methods 0.000 claims abstract description 30
- 239000002270 dispersing agent Substances 0.000 claims abstract description 24
- 238000000576 coating method Methods 0.000 claims abstract description 11
- 239000011248 coating agent Substances 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 39
- 239000005543 nano-size silicon particle Substances 0.000 claims description 35
- 239000000839 emulsion Substances 0.000 claims description 19
- 239000011856 silicon-based particle Substances 0.000 claims description 19
- 239000000843 powder Substances 0.000 claims description 16
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 229910021389 graphene Inorganic materials 0.000 claims description 14
- 239000002041 carbon nanotube Substances 0.000 claims description 13
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 13
- 229920003169 water-soluble polymer Polymers 0.000 claims description 12
- -1 super-p Chemical compound 0.000 claims description 11
- 229920002125 Sokalan® Polymers 0.000 claims description 10
- 239000007787 solid Substances 0.000 claims description 10
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims description 9
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 9
- 239000000661 sodium alginate Substances 0.000 claims description 9
- 235000010413 sodium alginate Nutrition 0.000 claims description 9
- 229940005550 sodium alginate Drugs 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 9
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 9
- 239000003232 water-soluble binding agent Substances 0.000 claims description 9
- 239000004584 polyacrylic acid Substances 0.000 claims description 8
- 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 7
- 238000010008 shearing Methods 0.000 claims description 7
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 7
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 7
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 7
- 239000004354 Hydroxyethyl cellulose Substances 0.000 claims description 6
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000002134 carbon nanofiber Substances 0.000 claims description 6
- 229920001477 hydrophilic polymer Polymers 0.000 claims description 6
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 6
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 6
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 6
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 5
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 5
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 5
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 5
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 5
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 5
- 229920002472 Starch Polymers 0.000 claims description 4
- 229910021382 natural graphite Inorganic materials 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 4
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 239000008107 starch Substances 0.000 claims description 4
- 235000019698 starch Nutrition 0.000 claims description 4
- 239000002033 PVDF binder Substances 0.000 claims description 3
- 229920002845 Poly(methacrylic acid) Polymers 0.000 claims description 3
- 239000006230 acetylene black Substances 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000003273 ketjen black Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 229920002401 polyacrylamide Polymers 0.000 claims description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000013019 agitation Methods 0.000 claims 1
- 239000010410 layer Substances 0.000 description 12
- 239000006185 dispersion Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 9
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 8
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 8
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 8
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 6
- 239000002174 Styrene-butadiene Substances 0.000 description 5
- 230000001351 cycling effect Effects 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 4
- 230000002209 hydrophobic effect Effects 0.000 description 4
- 238000001000 micrograph Methods 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 239000002153 silicon-carbon composite material Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229920002319 Poly(methyl acrylate) Polymers 0.000 description 2
- 239000002202 Polyethylene glycol Substances 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- 235000015165 citric acid Nutrition 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004005 microsphere Substances 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 229920001467 poly(styrenesulfonates) Polymers 0.000 description 2
- 229920001223 polyethylene glycol Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 229920001451 polypropylene glycol Polymers 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 239000011970 polystyrene sulfonate Substances 0.000 description 2
- 229960002796 polystyrene sulfonate Drugs 0.000 description 2
- 229920001289 polyvinyl ether Polymers 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 description 1
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910001290 LiPF6 Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000004368 Modified starch Substances 0.000 description 1
- 229920000881 Modified starch Polymers 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910000457 iridium oxide Inorganic materials 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 235000019426 modified starch Nutrition 0.000 description 1
- 239000002048 multi walled nanotube Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
- H01M4/623—Binders being polymers fluorinated polymers
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a silicon-carbon negative electrode plate and a preparation method thereof, and a lithium ion battery, wherein the preparation method comprises the following steps: dispersing a first conductive agent in a dispersing agent solution to obtain a first mixed solution; mixing the active particles, a first binder and a second conductive agent to obtain first particles; placing the first particles and the second binder in the first mixed solution to obtain a second mixed solution; mixing the second mixed solution with graphite, and coating the mixture on a current collector to obtain a silicon-carbon negative electrode plate; wherein the first conductive agent is a linear conductive agent and/or a planar conductive agent, and the second conductive agent is a linear conductive agent. The preparation method of the invention can obviously improve the long-period circulation stability of the obtained silicon-carbon negative electrode plate, has stable structure and long service life, can effectively improve the battery performance when being applied to lithium ion batteries, and has good application prospect.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a silicon-carbon negative electrode plate, a preparation method thereof and a lithium ion battery.
Background
Lithium ion batteries are a type of energy storage device that can be recycled, also called lithium ion secondary batteries, and mainly consist of a positive electrode, a negative electrode, a separator, and an electrolytic liquid system. The battery is characterized by a high energy density, no memory effect and low self-discharge compared to other primary batteries. The current commercial anode material is graphite, the theoretical specific capacity is 372 mAh.g -1, and the requirement of a high-energy-density battery can not be met, so that the development of the anode active material with high capacity is urgently needed.
Silicon has the characteristics of high theoretical specific capacity (4200 mA h g -1), low working voltage and the like, so that the silicon is widely researched, has abundant reserves in the crust, is low in cost and environment-friendly, and is one of the anode materials of the lithium ion battery of the next generation with the highest potential, but the cycle performance and the service life of the battery are seriously influenced by huge volume expansion of the silicon in the charge and discharge processes. Often, the surface modification of the silicon particles is carried out by various means, and then the silicon particles are mixed with graphite to obtain the silicon-carbon composite particles, so that the expansion of the silicon-carbon composite particles can be effectively relieved. However, in the cycling process, the stability of the pole piece is also important in the preparation process of the pole piece except that the pole piece is related to the active material, otherwise, the expansion and the cycling performance of the silicon-carbon negative electrode are also affected.
In order to improve the stability of the pole piece, CN209104267U adopts a graphite buffer layer and a graphene protective layer, the graphite buffer layer can absorb and release stress generated by volume expansion of silicon in a silicon-carbon material in the charge-discharge process, pulverization and falling of a silicon-carbon active layer are prevented, and graphite is used as a negative electrode material of a lithium ion battery. CN102891290B also adopts graphene to mitigate expansion of silicon-based particles. However, graphene is not easily dispersed, and conductivity decreases after modification.
CN107275572a discloses a novel negative electrode plate, the surface of the negative electrode current collector is coated with a layer of negative electrode ceramic layer, the negative electrode ceramic is at least one of magnesium oxide, zirconium oxide, titanium dioxide, iridium oxide and aluminum oxide, the thickness is 3 μm-5 μm, the ceramic membrane adopted by the novel negative electrode plate and the negative electrode plate coated with the ceramic layer have high temperature resistance, and the safety and the thermal stability of the lithium ion battery can be improved. However, the addition of the oxide may cause a decrease in the conductive performance of the current collector.
CN107768595A adopts ion sputtering, vacuum evaporation, chemical growth or physical coating method to generate a film solid electrolyte layer on one surface of the electrode plate containing the negative electrode active material to obtain the negative electrode plate of the lithium ion battery, and the negative electrode plate of the lithium ion battery has the advantages of stable structure, long service life, wide and stable electrochemical window, long storage and circulation life, unaffected basic electrochemical performance and the like. However, the technical operation is difficult, and the thickness of the solid electrolyte layer is not easy to control.
It is noted that the information disclosed in the foregoing background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to overcome at least one defect of the prior art, and provides a silicon-carbon negative electrode plate, a preparation method thereof and a lithium ion battery, so as to solve the problems of low stability, poor cycle performance, short service life and the like of the existing silicon-carbon negative electrode plate.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
The first aspect of the invention provides a preparation method of a silicon-carbon negative electrode plate, comprising the following steps: dispersing a first conductive agent in a dispersing agent solution to obtain a first mixed solution; mixing the active particles, a first binder and a second conductive agent to obtain first particles; placing the first particles and the second binder in the first mixed solution to obtain a second mixed solution; mixing the second mixed solution with graphite, and coating the mixture on a current collector to obtain a silicon-carbon negative electrode plate; wherein the first conductive agent is a linear conductive agent and/or a planar conductive agent, and the second conductive agent is a linear conductive agent.
According to an embodiment of the present invention, the first conductive agent is selected from one or more of carbon nanotubes, carbon nanofibers and graphene, and the second conductive agent is selected from one or more of carbon nanotubes, super-p, acetylene black, ketjen black and carbon nanofibers.
According to one embodiment of the present invention, the first conductive agent is a water-soluble conductive agent, and the dispersant solution is a water-soluble polymer solution.
According to one embodiment of the invention, the mass fraction of the water-soluble polymer in the water-soluble polymer solution is 1% -10%, preferably 1% -6%; the water-soluble polymer is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, modified starch, sodium alginate, citric acid, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone and polyvinyl alcohol.
According to one embodiment of the present invention, the first conductive agent accounts for 0.01 to 0.1% by mass of the first mixed solution, and preferably 0.02 to 0.06%; the dispersant solution accounts for 99.90 to 99.99 percent, preferably 99.94 to 99.98 percent of the mass of the first mixed solution.
According to one embodiment of the present invention, a homogenizer or a shear is used to disperse the first conductive agent in the dispersant solution; when a shear is used, the rotation speed of the shear is 1000rpm to 2000rpm, preferably 1500rpm to 1800rpm, and the shearing time is 1h to 8h, preferably 2h to 4h.
According to one embodiment of the invention, the active particles are a mixture of spherical graphite and silicon-based particles selected from nano-silicon and/or nano-silicon oxide SiO x, wherein 0< x <2; the mass ratio of the spherical graphite to the silicon-based particles is 1-4:1, preferably 1-2:1.
According to one embodiment of the invention, the silicon-based particles are carbon-coated silicon-based particles, wherein the carbon coating has a thickness of 2nm to 10nm.
According to one embodiment of the invention, the nano-silicon has a particle size of 20nm to 500nm, preferably 50nm to 150nm; the nano silicon is pure nano silicon and/or nano silicon with oxidized surface, the oxygen content of the nano silicon with oxidized surface is less than 5%, the oxidation thickness is 1 nm-20 nm, and the preferable thickness is 1 nm-10 nm; the particle size of the nano silicon oxide SiO x is 10 nm-200 nm, preferably 10 nm-100 nm, wherein, preferably, 0.3< x <1.6.
According to one embodiment of the invention, the first binder is a binding powder, the binding powder being a hydrophilic polymer and/or an amphiphilic polymer; wherein the hydrophilic polymer is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate and polyacrylic acid; the amphiphilic polymer is formed by copolymerizing a hydrophilic segment and a hydrophobic segment, wherein the hydrophilic segment is one or more selected from polyethylene glycol, polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, polyacrylic acid and polystyrene sulfonate, and the hydrophobic segment is one or more selected from polypropylene oxide, polymethyl methacrylate, polymethyl acrylate, polystyrene and polysiloxane.
According to one embodiment of the present invention, further comprising: mixing the active particles with a first binder to obtain active particles coated by the first binder; mixing the active particles coated by the first binder with a second conductive agent to obtain first particles; wherein the mass ratio of the first binder to the active particles is (15-2): (85-98), preferably (10-3): (90-97); the mass ratio of the second conductive agent to the active particles coated by the first binder is (1-20): 99-80, preferably (5-20): 80-95.
According to one embodiment of the invention, the mixing of the first binder and the active particles and/or the mixing of the second conductive agent and the active particles coated with the first binder is performed using a planetary ball mill or a powder mixer at a rotational speed of 100rpm to 500rpm for a time of 1h to 12h, preferably 1h to 6h.
According to one embodiment of the invention, the second binder is a water-soluble binder emulsion, the water-soluble binder emulsion comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber, polymethacrylic acid, sodium alginate and polytetrafluoroethylene, and the solid content of the water-soluble binder emulsion is 1-60 wt%.
According to one embodiment of the present invention, further comprising: dispersing the first particles in the first mixed solution to obtain a third mixed solution; adding a second binder into the third mixed solution, and stirring to obtain a second mixed solution; wherein the addition amount of the second binder accounts for 1-8% of the mass of the third mixed solution, and is preferably 1-4%.
According to one embodiment of the invention, the first particles are dispersed in the first mixed solution by a vacuum stirrer at a rotation speed of 200rpm to 1000rpm for 2 hours to 12 hours, preferably 350rpm to 600rpm for 3 hours to 6 hours; and adding the second binder into the third mixed solution by adopting a vacuum stirrer, and stirring at the rotating speed of 200-900 rpm for 1-10 h, preferably 200-500 rpm for 1-3 h.
According to one embodiment of the invention, the method further comprises the steps of adding the second binder into the third mixed solution, and adding graphite for mixing in the stirring process; the mass ratio of the addition amount of graphite to the first particles is 0.5-4:1, preferably 1-2:1.
According to one embodiment of the invention, the graphite is spherical graphite selected from one or more of spherical natural graphite, spherical artificial graphite and spherical carbon microspheres, the tap density of the spherical graphite is 0.8g cm -3～1.1g cm-3, and the median particle diameter is 10-25 μm.
The second aspect of the invention provides a silicon-carbon negative electrode plate prepared by the method.
The third aspect of the invention provides a lithium ion battery, which comprises a positive electrode and a negative electrode, wherein the negative electrode adopts the silicon-carbon negative electrode piece.
According to the technical scheme, the beneficial effects of the invention are as follows:
According to the method for preparing the silicon-carbon negative electrode plate, a specific process is adopted, and a specific binder and a conductive agent are selected, so that on one hand, the conductivity of a dispersing agent solution is enhanced, and the dispersing agent solution plays a role of a conductive network in the electrode plate after being dried; on the other hand, the mode that the active particles are directly contacted with the conductive agent is changed, bonding powder and the like are added to improve the surface cohesiveness of the active particles, promote the dispersion of the conductive agent on the surfaces of the particles, further promote the dispersion of the conductive agent, and reduce the conductive resistance of the contact between the particles. The preparation method of the invention can obviously improve the long-period circulation stability of the obtained silicon-carbon negative electrode plate, has stable structure and long service life, can effectively improve the battery performance when being applied to lithium ion batteries, and has good application prospect.
Drawings
The following drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain the invention, without limitation to the invention.
FIG. 1 is a flow chart of a process for preparing a silicon-carbon negative electrode sheet according to one embodiment of the present invention;
FIG. 2 is a scanning electron microscope image of a silicon carbon negative electrode sheet of example 1;
FIG. 3 is a scanning electron microscope image of graphene used in example 3;
FIG. 4 is a graph showing the cycling performance of lithium ion batteries prepared from the silicon carbon negative electrode sheets of example 1 and comparative example 1;
Fig. 5 is a graph of cycling performance of lithium ion batteries prepared from the silicon carbon negative electrode sheets of example 2 and comparative example 2.
Detailed Description
The following provides various embodiments or examples to enable those skilled in the art to practice the invention as described herein. These are, of course, merely examples and are not intended to limit the invention from that described. The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and should be considered as specifically disclosed herein.
Fig. 1 is a process flow chart of preparing a silicon-carbon negative electrode plate according to an embodiment of the present invention, and as shown in fig. 1, the present invention provides a method for preparing a silicon-carbon negative electrode plate, including: dispersing a first conductive agent in a dispersing agent solution to obtain a first mixed solution; mixing the active particles, a first binder and a second conductive agent to obtain first particles; placing the first particles and the second binder in the first mixed solution to obtain a second mixed solution; mixing the second mixed solution with graphite, and coating the mixture on a current collector to obtain a silicon-carbon negative electrode plate; wherein the first conductive agent is a linear conductive agent and/or a planar conductive agent, and the second conductive agent is a linear conductive agent.
According to the invention, the performance of the electrode material is improved by adopting a silicon-carbon composite mode at present, however, the inventor of the invention discovers that the stability of the pole piece is particularly important in the process of preparing the pole piece except the stability of the pole piece related to the active material in the process of circulation, otherwise, the expansion of the silicon-carbon negative electrode, the circulation performance and the like are also influenced. Therefore, the invention provides a new preparation method of the silicon-carbon negative electrode plate, which changes the mode of not carrying the conductive agent in the traditional dispersing agent solution, and enhances the conductivity of the silicon-carbon negative electrode plate by adding specific conductive agent, binder and the like into the dispersing agent solution according to a specific sequence, and plays a role of a conductive network in the electrode plate after drying; in addition, the invention changes the mode that the active particles are directly contacted with the conductive agent, and the bonding powder and the like are added to improve the surface bonding property of the active particles, promote the dispersion of the conductive agent on the surfaces of the particles, further promote the dispersion of the conductive agent and reduce the conductive resistance of the contact between the particles. By adopting a specific process and selecting a specific conductive agent and a binder, the long-period cycling stability of the obtained silicon-carbon negative electrode plate is obviously improved, and the silicon-carbon negative electrode plate can be applied to a lithium ion battery, so that the battery performance can be effectively improved, and has a good application prospect.
The following specifically describes a method for preparing a silicon-carbon negative electrode sheet according to an embodiment of the present invention with reference to fig. 1.
First, a first conductive agent is dispersed in a dispersant solution to obtain a first mixed solution.
Specifically, the first conductive agent is a linear conductive agent and/or a planar conductive agent, wherein the linear conductive agent is preferably a carbon nanotube, a carbon nanofiber, or the like, or a combination thereof, and the planar conductive agent is preferably graphene. The dispersing agent solution is water-soluble polymer solution, wherein the water-soluble polymer is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, starch, sodium alginate, citric acid, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol and the like, the solvent is pure water, and the mass fraction is 1% -10%, for example, 1%, 2%, 3%, 4%, 6%, 8%, 10% and the like, preferably 1% -6%. By selecting a linear conductive agent and/or a planar conductive agent as the first conductive agent, a conductive network can be formed in the dispersant solution, thereby enhancing the conductivity of the dispersant solution.
Preferably, the carbon nanotubes are metal multi-wall carbon nanotubes, the diameter of the tube bundle is 10 nm-100 nm, and the length is 1 μm-50 μm. The graphene is preferably few-layer graphene, the thickness of the sheet layer is 3-10 layers, and the size is 1-30 mu m. In order to increase the conductivity of the dispersant solution, linear and planar conductive agents may be used in combination, and the first conductive agent may be a hydrophilically modified first conductive agent, that is, a water-soluble conductive agent, so that the hydrophilicity thereof is enhanced, thereby enhancing the dispersibility of the first conductive agent in the solution.
In some embodiments, the dispersion of the first conductive agent in the dispersant solution may be performed using a homogenizer or a shear to achieve uniform dispersion of the conductive agent. For example, when a shearing machine is used, the rotation speed is 1000rpm to 2000rpm, and the time is 1h to 8h, preferably 1500rpm to 1800rpm, and 2h to 4h.
In some embodiments, the first conductive agent comprises 0.01% to 0.1% by mass of the first mixed solution, for example, 0.01%, 0.02%, 0.05%, 0.06%, 0.08%, 0.1%, etc., preferably 0.02% to 0.06%; the dispersant solution accounts for 99.90 to 99.99 percent, preferably 99.94 to 99.98 percent of the mass of the first mixed solution.
Next, the active particles, the first binder, and the second conductive agent are mixed to obtain first particles. Of course, the first particles may be prepared first and then the first mixed solution may be prepared, and the present invention is not limited to the above-mentioned preparation procedure.
Specifically, the active particles are a mixture of spherical graphite and silicon-based particles, the spherical graphite can be spherical natural graphite, spherical artificial graphite and the like, the tap density of the spherical graphite is 0.8g cm -3～1.1g cm-3, and the median particle diameter is 10-25 μm. The silicon-based particles are selected from nano-silicon and/or nano-silicon oxide SiO x, wherein 0< x <2, preferably 0.3< x <1.6. The mass ratio of the spherical graphite to the silicon-based particles is 1-4:1, preferably mixed according to the ratio of 1:1. The grain diameter of the nano silicon is 20 nm-500 nm, preferably 50 nm-150 nm; the nano silicon is pure nano silicon and/or nano silicon with oxidized surface, the oxygen content of the nano silicon with oxidized surface is less than 5%, the oxidation thickness is 1 nm-20 nm, and the preferable thickness is 1 nm-10 nm; the particle size of the nano silicon oxide SiO x is 10 nm-200 nm, preferably 10 nm-100 nm.
In some embodiments, the aforementioned silicon-based particles are preferably carbon-coated silicon-based particles, wherein the carbon coating has a thickness of 2nm to 10nm. The carbon coating can be vapor deposition, thermal cracking, and the like.
The first binder is bonding powder, and the bonding powder is hydrophilic polymer and/or amphiphilic polymer; wherein the hydrophilic polymer is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate and polyacrylic acid; the amphiphilic polymer is formed by copolymerizing a hydrophilic segment and a hydrophobic segment, wherein the hydrophilic segment is one or more selected from polyethylene glycol, polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, polyacrylic acid and polystyrene sulfonate, and the hydrophobic segment is one or more selected from polypropylene oxide, polymethyl methacrylate, polymethyl acrylate, polystyrene and polysiloxane.
The second conductive agent is a linear conductive agent, preferably one or more of carbon nanotubes, super-p, acetylene black, ketjen black and carbon nanofibers. By mixing the linear second conductive agent with the bonding powder and the active particles, the manner that the active particles are directly contacted with the conductive agent can be changed, the bonding powder is utilized to improve the surface bonding property of the active particles, and the dispersion of the second conductive agent on the surfaces of the particles is promoted, so that the dispersion of the second conductive agent is promoted, and meanwhile, the second conductive agent is the linear conductive agent, so that a fibrous conductive network can be formed, the conductive resistance of contact between the particles can be reduced, and meanwhile, the expansion of the silicon particles can be reduced.
In some embodiments, further comprising: mixing the active particles with a first binder to obtain active particles coated by the first binder; mixing the active particles coated by the first binder with a second conductive agent to obtain first particles; wherein the mass ratio of the first binder to the active particles is (15-2): (85-98), preferably (10-3): (90-97); the mass ratio of the second conductive agent to the active particles coated by the first binder is (1-20): 99-80, preferably (5-20): 80-95.
Preferably, the mixing of the first binder and the active particles, and the mixing of the second conductive agent and the active particles coated with the first binder can be performed by a planetary ball mill or a powder mixer at a rotation speed of 100rpm to 500rpm for 1h to 12h, preferably 1h to 6h. Preferably, the planetary ball mill is used for mixing, the rotating speed is 200 rpm-350 rpm, and the time is 1 h-6 h.
Further, the obtained first particles and the second binder are placed in the prepared first mixed solution to obtain a second mixed solution.
Specifically, the second binder is a water-soluble binder emulsion, i.e., in a water-soluble emulsion state, and the water-soluble binder emulsion includes one or more of polyvinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber, polymethacrylic acid, sodium alginate and polytetrafluoroethylene, preferably vinylidene fluoride, polytetrafluoroethylene, styrene-butadiene rubber emulsion or a combination thereof, and the solid content of the water-soluble binder emulsion is 1wt% to 60wt%, for example, 1wt%, 5wt%, 10wt%, 20wt%, 25wt%, 40wt%, and the like.
In some embodiments, further comprising: dispersing the first particles in the first mixed solution to obtain a third mixed solution; adding a second binder into the third mixed solution, and stirring to obtain a second mixed solution; the amount of the second binder added is 1% to 8% by mass, for example, 1%, 3%, 4%, 5%, 6%, 8% by mass, and preferably 1% to 4% by mass of the third mixed solution.
Preferably, the first particles are dispersed in the first mixed solution by using a vacuum stirrer at a rotation speed of 200rpm to 1000rpm, for example, 200rpm, 300rpm, 500rpm, 600rpm, etc., for a mixing time of 2 hours to 12 hours, preferably 350rpm to 600rpm, for a time of 3 hours to 6 hours. Preferably, after the second binder is added to the third mixed solution, a vacuum mixer is also used at a rotation speed of 200rpm to 900rpm, for example, 200rpm, 300rpm, 500rpm, 600rpm, etc., for a mixing time of 1h to 10h, preferably 200h to 500rpm, for a time of 1h to 3h.
And finally, mixing the prepared second mixed solution with graphite, and coating the mixture on a current collector to obtain the silicon-carbon negative electrode plate.
Preferably, after adding the second binder to the third mixed solution, adding graphite during stirring, for example, when the mixing time is half of the mixing time; the mass ratio of the addition amount of graphite to the first particles is 0.5-4:1, preferably 1-2:1.
The graphite is preferably spherical graphite, the spherical graphite is selected from one or more of spherical natural graphite, spherical artificial graphite and spherical carbon microspheres, the tap density of the spherical graphite is 0.8g cm -3～1.1g cm-3, and the median particle diameter is 10-25 μm. Preferably, the graphite used herein is the same graphite as the graphite used in the active particles, although different types of graphite may be used, and the invention is not limited thereto.
In summary, the invention provides a new method for preparing the silicon-carbon negative electrode plate, which adopts a specific process and a specific selected binder and conductive agent to enhance the conductivity of the dispersant solution on one hand, so that the dispersant solution plays a role of a conductive network in the electrode plate after being dried; on the other hand, the mode that the active particles are directly contacted with the conductive agent is changed, bonding powder and the like are added to improve the surface cohesiveness of the active particles, promote the dispersion of the conductive agent on the surfaces of the particles, further promote the dispersion of the conductive agent, and reduce the conductive resistance of the contact between the particles. The preparation method of the invention can obviously improve the long-period cycle stability of the obtained silicon-carbon negative electrode plate, can effectively improve the battery performance when being applied to lithium ion batteries, and has good application prospect.
The invention will be further illustrated by the following examples, but the invention is not limited thereby. The reagents, materials, etc. used in the present invention are commercially available unless otherwise specified.
The dispersion solutions used in the following examples were sodium carboxymethylcellulose (CMC) hydrosol, 1.5wt% and SBR emulsion as the second binder, ZOEN BM-451B emulsion, 40wt% and 4-fold diluted for use. The active particles are lower fine particles obtained by sieving through a 325-mesh quasi-sieve.
The morphology of the active particle material and the morphology of the various silicon-carbon composite materials prepared in the examples were observed by a scanning electron microscope (Hitachi SU8010,3 kV).
Example 1
(1) 0.02G of Carbon Nanotubes (CNT) is dispersed in 99.98g of CMC glue solution by a blade stirrer to obtain a first mixed solution, wherein CMC hydrosol is colorless clear colloid with the mass fraction of 1.5wt%.
(2) Mixing nano silicon with the particle size of about 100nm with asphalt according to the mass ratio of 10:1, and then carrying out thermal cracking carbonization for 3 hours at 600 ℃ in an argon atmosphere to obtain the carbon-coated nano silicon.
(3) The carbon-coated nano-silicon prepared in spherical artificial graphite (Bei Terui SAG series) and (2) was mixed into active particles 20g according to a ratio of 1:1, mixed with binding powder CMC to be coated, the mixing ratio was 95:5, and the coated particles were mixed with super-p, the mixing ratio was 85:15, to obtain first particles of 24.7 g.
(4) 24.7G of the first particles were dispersed in 100g of the first mixed solution using a vacuum stirrer, wherein the rotation speed was 500rpm, for 4 hours.
(5) And (3) adding 5g of SBR emulsion (with solid content of 40%) into the solution obtained in the step (4), stirring to obtain a second mixed solution, wherein the solid content of the SBR emulsion accounts for 2% of the mass of the second mixed solution, and mixing the second mixed solution with spherical graphite, and the adding amount of the spherical graphite is 72.5g.
(6) And (3) coating the slurry obtained in the step (5) on a current collector, wherein the current collector is a carbon-spraying copper current collector, and after the slurry is coated on the current collector, the pole piece is firstly dried in a drying oven for about 10 minutes, and then is dried in a vacuum oven at 90 ℃ for 10 hours. And after the completion, rolling to obtain the silicon-carbon negative electrode plate.
Fig. 2 is a scanning electron microscope image of the silicon carbon negative electrode sheet of example 1, and it can be seen from fig. 2 that the silicon carbon particles are mostly tens of micrometers, and the nano silicon is relatively uniformly distributed around the graphite.
Example 2
The method and raw materials of example 1 were used to prepare a silicon carbon negative electrode sheet, except that carbon-coated nano silicon oxide was used in step (2), wherein the particle size of the nano silicon oxide SiO 2 was about 80 nm.
Example 3
The method and the raw material of example 1 are adopted to prepare the silicon-carbon negative electrode sheet, except that graphene is adopted to replace carbon nanotubes in step (1), and fig. 3 is a scanning electron microscope image of the graphene used in example 3, and the thickness of the graphene sheet is about 4 layers and the size is about 10 micrometers as shown in fig. 3.
Example 4
The silicon-carbon negative electrode sheet was prepared by the method and raw materials of example 1, except that in step (4), 4.0g of SBR emulsion (solid content 40%) and 6.7g of PAA emulsion (solid content 6%) were added to the solution obtained in step (3) and stirred to obtain a second mixed solution, wherein the total solid content of SBR emulsion and PAA emulsion was 2% by mass of the second mixed solution.
Comparative example 1
A silicon carbon negative electrode sheet was prepared as in example 1, except that CNT was replaced with super-p in step (1).
Comparative example 2
A silicon carbon negative electrode sheet was prepared as in example 2, except that step (3) was changed to starch for the bonding powder CMC.
Comparative example 3
A silicon carbon negative electrode sheet was prepared as in example 1, except that super-b in step (3) was changed to graphene.
Comparative example 4
Carbon-coated nano-silicon was prepared as in example 1, and then 20g of carbon-coated nano-silicon, 0.02g of carbon nanotubes, 72.5g of spherical graphite, and 3.5g of super-p were mixed together into 99.98g of CMC gel solution, wherein the CMC hydrosol was colorless clear colloid with a mass fraction of 1.5wt%.
Test case
The silicon carbon negative electrode tabs of the above examples and comparative examples were assembled into lithium ion batteries, specifically: the prepared electrode plate is used as an anode, the metal lithium plate is used as a cathode, celgard 2400 type diaphragm is selected, 1 mol.L -1LiPF6 (volume ratio is ethylene carbonate: dimethyl carbonate: diethyl carbonate=1:1:1) electrolyte is added with 5% fluoroethylene carbonate, a button half cell is assembled in a glove box, and a blue electric system is used for testing the charge and discharge of the cell. The parameters are set as follows: the current density is 0.1C for the first circle, 0.2C for the subsequent, and the voltage interval is 0.005-1.5V. The specific test results are shown in table 1 below:
TABLE 1
Fig. 4 is a cycle performance chart of lithium ion batteries prepared from the silicon carbon negative electrode sheets of example 1 and comparative example 1, and fig. 5 is a cycle performance chart of lithium ion batteries prepared from the silicon carbon negative electrode sheets of example 2 and comparative example 2, and it can be seen that CNT or super-p linear conductive agent can improve the cycle stability of the electrode sheets more than graphene planar conductive agent, and CMC has carboxymethyl groups more than starch. In addition, the conductive agent and the binder are added step by step, so that the stability of the pole piece can be improved compared with the case that all materials are added at one time.
It will be appreciated by persons skilled in the art that the embodiments described herein are merely exemplary and that various other alternatives, modifications and improvements may be made within the scope of the invention. Thus, the present invention is not limited to the above-described embodiments, but only by the claims.
Claims (26)
1. The preparation method of the silicon-carbon negative electrode plate is characterized by comprising the following steps of:
dispersing a first conductive agent in a dispersing agent solution to obtain a first mixed solution;
mixing the active particles, a first binder and a second conductive agent to obtain first particles;
Placing the first particles and the second binder in the first mixed solution to obtain a second mixed solution; and
Mixing the second mixed solution with graphite, and then coating the mixture on a current collector to obtain the silicon-carbon negative electrode plate;
Wherein the first conductive agent is selected from one or more of carbon nanotubes, carbon nanofibers and graphene, and the second conductive agent is selected from one or more of carbon nanotubes, super-p, acetylene black, ketjen black and carbon nanofibers; the first binder is binding powder;
The active particles are a mixture of spherical graphite and silicon-based particles, and the mass ratio of the spherical graphite to the silicon-based particles is 1-4:1;
mixing the active particles with the first binder to obtain first binder-coated active particles; the active particles wrapped by the first binder are mixed with the second conductive agent to obtain the first particles; the first binder and the active particles are mixed, and the second conductive agent and the active particles wrapped by the first binder are mixed by adopting a planetary ball mill or a powder mixer, wherein the rotating speed is 100 rpm-500 rpm, and the time is 1 h-12 h;
The bonding powder is a hydrophilic polymer, and the hydrophilic polymer is one or more selected from sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate and polyacrylic acid.
2. The method according to claim 1, wherein the first conductive agent is a hydrophilically modified first conductive agent, and the dispersant solution is a water-soluble polymer solution.
3. The preparation method according to claim 2, wherein the mass fraction of the water-soluble polymer in the water-soluble polymer solution is 1% -10%; the water-soluble polymer is selected from one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, starch, sodium alginate, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone and polyvinyl alcohol.
4. The method according to claim 3, wherein the mass fraction of the water-soluble polymer in the water-soluble polymer solution is 1% to 6%.
5. The preparation method of claim 1, wherein the first conductive agent accounts for 0.01-0.1% of the first mixed solution by mass; the dispersant solution accounts for 99.90-99.99% of the first mixed solution by mass percent.
6. The preparation method of claim 5, wherein the first conductive agent accounts for 0.02-0.06% of the first mixed solution by mass; the dispersant solution accounts for 99.94-99.98% of the first mixed solution by mass.
7. The method of claim 1, wherein the first conductive agent is dispersed in the dispersant solution using a homogenizer or a shear; when the shearing machine is adopted, the rotating speed of the shearing machine is 1000 rpm-2000 rpm, and the shearing time is 1 h-8 h.
8. The method according to claim 7, wherein the rotation speed of the shearing machine is 1500 rpm-1800 rpm, and the shearing time is 2h-4h.
9. The method of claim 1, wherein the silicon-based particles are selected from nano-silicon and/or nano-silicon oxide SiO x, wherein 0< x <2.
10. The method of claim 1, wherein the mass ratio of the spherical graphite to the silicon-based particles is 1-2:1.
11. The method of claim 9, wherein the silicon-based particles are carbon-coated silicon-based particles, wherein the carbon coating has a thickness of 2nm to 10nm.
12. The method of claim 9, wherein the nano-silicon has a particle size of 20nm to 500nm; the nano silicon is pure nano silicon and/or nano silicon with oxidized surface, the oxygen content of the nano silicon with oxidized surface is less than 5%, and the oxidation thickness is 1 nm-20 nm; the particle size of the nano silicon oxide SiO x is 10 nm-200 nm.
13. The method of claim 12, wherein the nano-silicon has a particle size of 50nm to 150nm; the oxidation thickness of the nano silicon with oxidized surface is 1 nm-10 nm; the particle size of the nano silicon oxide SiO x is 10 nm-100 nm, and x is 0.3< 1.6.
14. The method of claim 1, wherein the mass ratio of the first binder to the active particles is (2-15): 85-98; the mass ratio of the second conductive agent to the active particles wrapped by the first binder is (1-20): 99-80.
15. The method of claim 14, wherein the mass ratio of the first binder to the active particles is (3-10): 90-97; the mass ratio of the second conductive agent to the active particles wrapped by the first binder is (5-20): 80-95.
16. The method of claim 1, wherein the second conductive agent is mixed with the active particles coated with the first binder for a period of time ranging from 1h to 6h.
17. The preparation method according to claim 1, wherein the second binder is a water-soluble binder emulsion, the water-soluble binder emulsion comprises one or more of polyvinylidene fluoride, styrene-butadiene rubber, polymethacrylic acid, sodium alginate and polytetrafluoroethylene, and the solid content of the water-soluble binder emulsion is 1-60 wt%.
18. The method of manufacturing according to claim 1, further comprising: dispersing the first particles in the first mixed solution to obtain a third mixed solution; adding the second binder into the third mixed solution, and stirring to obtain the second mixed solution; wherein the addition amount of the solid content of the second binder accounts for 1-8% of the mass of the third mixed solution.
19. The method according to claim 18, wherein the second binder has a solid content of 1 to 4% by mass of the third mixed liquid.
20. The method of claim 18, wherein the first particles are dispersed in the first mixed solution by a vacuum stirrer at a rotation speed of 200rpm to 1000rpm for a mixing time of 2 hours to 12 hours; and adding the second binder into the third mixed solution by adopting a vacuum stirrer, and stirring at the rotating speed of 200-900 rpm for 1-10 h.
21. The method according to claim 20, wherein the vacuum mixer disperses the first particles in the first mixed liquid at a rotational speed of 350rpm to 600rpm for 3 hours to 6 hours; and the second binder is added into the third mixed solution by the vacuum stirrer, and the stirring speed is 200-500 rpm, and the time is 1-3 h.
22. The method of claim 18, further comprising adding the graphite during agitation after adding the second binder to the third mixture; the mass ratio of the addition amount of the graphite to the first particles is 0.5-4:1.
23. The method of claim 22, wherein the mass ratio of the graphite to the first particles is 1-2:1.
24. The method according to claim 1, wherein the graphite is spherical graphite, the spherical graphite is one or more selected from spherical natural graphite and spherical artificial graphite, the tap density of the spherical graphite is 0.8g cm -3～1.1g cm-3, and the median particle diameter is 10 μm to 25 μm.
25. A silicon carbon negative electrode sheet prepared by the method of any one of claims 1 to 24.
26. A lithium ion battery comprising a positive electrode and a negative electrode employing the silicon-carbon negative electrode tab of claim 25.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110184727.XA CN114914444B (en) | 2021-02-10 | 2021-02-10 | Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110184727.XA CN114914444B (en) | 2021-02-10 | 2021-02-10 | Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114914444A CN114914444A (en) | 2022-08-16 |
| CN114914444B true CN114914444B (en) | 2024-08-09 |
Family
ID=82761947
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110184727.XA Active CN114914444B (en) | 2021-02-10 | 2021-02-10 | Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114914444B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107946561A (en) * | 2017-11-13 | 2018-04-20 | 深圳市比克动力电池有限公司 | Negative material and preparation method thereof, cathode pole piece and lithium ion battery |
| CN111883760A (en) * | 2020-07-29 | 2020-11-03 | 黄杰 | Composite nano silicon cathode and preparation and application thereof |
Family Cites Families (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003272634A (en) * | 2002-03-12 | 2003-09-26 | Hitachi Maxell Ltd | Nonaqueous secondary battery |
| JP2007095534A (en) * | 2005-09-29 | 2007-04-12 | Matsushita Electric Ind Co Ltd | Method of manufacturing nonaqueous electrolyte secondary battery |
| CN102569733B (en) * | 2010-12-21 | 2016-03-09 | 比克国际(天津)有限公司 | The preparation method of pulp of lithium ion battery, cell size and lithium ion battery |
| KR101449786B1 (en) * | 2011-05-26 | 2014-10-13 | 주식회사 엘지화학 | Lithium secondary battery with enhanced conductivity property |
| CN103833034B (en) * | 2014-02-12 | 2015-11-25 | 浙江天乐新材料科技有限公司 | A kind of CNT (carbon nano-tube), Graphene of utilizing prepares the method for silicon carbide slurry for carbon source |
| CN104681306A (en) * | 2014-12-12 | 2015-06-03 | 宁波南车新能源科技有限公司 | Preparation method for mixed capacitor cathode pulp |
| CN105576248B (en) * | 2016-02-25 | 2018-09-28 | 中国科学院金属研究所 | A kind of silicon-carbon cathode combined conductive agent slurry and its preparation method and application |
| KR102314626B1 (en) * | 2016-12-26 | 2021-10-20 | 주식회사 엘지에너지솔루션 | Electrode for secondary battery, method for preparing the same, and lithium secondary battery comprising the same |
| CN107658450A (en) * | 2017-09-18 | 2018-02-02 | 江苏道赢科技有限公司 | A kind of microcapsule-type silicon-carbon composite cathode material and its preparation method and application |
| CN108493452B (en) * | 2018-03-13 | 2021-06-01 | 陕西科技大学 | Water-based binder for inhibiting expansion of pole piece material, lithium ion battery negative electrode material based on water-based binder and preparation method |
| CN108598487A (en) * | 2018-05-15 | 2018-09-28 | 中航锂电（江苏）有限公司 | A kind of preparation method of negative electrode of lithium ion battery conductive gelatin |
| CN109301184A (en) * | 2018-09-10 | 2019-02-01 | 江苏塔菲尔新能源科技股份有限公司 | Modified composite material, preparation method and the purposes in lithium ion battery of siliceous substrates material |
| CN109360990A (en) * | 2018-12-03 | 2019-02-19 | 重庆市典盈新材料科技有限公司 | A kind of LiFePO4 battery core positive conductive agent slurry and preparation method thereof |
| CN109599532A (en) * | 2018-12-10 | 2019-04-09 | 江苏天鹏电源有限公司 | A kind of pulping process of silicium cathode material ternary lithium battery |
| CN109786665A (en) * | 2018-12-20 | 2019-05-21 | 上海力信能源科技有限责任公司 | A kind of silicon-carbon composite cathode pole piece and preparation method thereof |
| CN209104267U (en) * | 2018-12-25 | 2019-07-12 | 江西中汽瑞华新能源科技有限公司 | A kind of lithium ion battery silicon-carbon cathode pole piece |
| CN109841796B (en) * | 2019-02-27 | 2021-01-12 | 中国第一汽车股份有限公司 | Electrode preparation method and battery |
| CN110148751B (en) * | 2019-06-19 | 2021-01-12 | 桑德新能源技术开发有限公司 | Silicon-carbon cathode and preparation method thereof |
| CN110600671B (en) * | 2019-07-22 | 2021-11-26 | 恒大新能源科技集团有限公司 | Semi-dry method batching process of lithium ion battery electrode slurry, lithium ion battery positive plate, battery negative plate and lithium ion battery |
| CN110783559B (en) * | 2019-11-08 | 2021-06-11 | 东莞塔菲尔新能源科技有限公司 | Modified negative electrode material and preparation method and application thereof |
| CN112909251A (en) * | 2019-12-04 | 2021-06-04 | 广州汽车集团股份有限公司 | Negative electrode material active layer, negative electrode pole piece, lithium ion cell, lithium ion battery pack and application thereof |
| CN111244455A (en) * | 2020-01-15 | 2020-06-05 | 上海电气集团股份有限公司 | Silicon-carbon composite negative electrode material composite conductive agent of lithium ion battery, negative plate and preparation method of negative plate |
| CN114127989A (en) * | 2020-02-05 | 2022-03-01 | 宁德新能源科技有限公司 | Negative electrode sheet, electrode assembly, battery, and electronic device |
| CN111769266A (en) * | 2020-06-23 | 2020-10-13 | 合肥国轩高科动力能源有限公司 | Silicon-based negative electrode material and lithium ion battery containing same |
| CN111916745A (en) * | 2020-08-03 | 2020-11-10 | 清华大学 | Silicon negative electrode material, preparation method thereof and electrochemical cell |
| CN112133882B (en) * | 2020-08-31 | 2022-11-15 | 渤海大学 | Solvent-free preparation method of electrode for electrochemical energy storage device |
| CN112687843A (en) * | 2020-12-25 | 2021-04-20 | 惠州亿纬锂能股份有限公司 | Composite conductive agent suitable for silicon-based negative electrode, preparation method of silicon-based negative electrode and lithium ion battery |
| CN113380973B (en) * | 2021-06-15 | 2022-10-11 | 湖南美尼科技有限公司 | Preparation method of silicon-based negative electrode slurry |
| CN114628674A (en) * | 2021-07-06 | 2022-06-14 | 万向一二三股份公司 | Positive active material slurry, preparation method and positive pole piece |
-
2021
- 2021-02-10 CN CN202110184727.XA patent/CN114914444B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107946561A (en) * | 2017-11-13 | 2018-04-20 | 深圳市比克动力电池有限公司 | Negative material and preparation method thereof, cathode pole piece and lithium ion battery |
| CN111883760A (en) * | 2020-07-29 | 2020-11-03 | 黄杰 | Composite nano silicon cathode and preparation and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114914444A (en) | 2022-08-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7505783B2 (en) | Silicon-carbon composite anode material | |
| KR101785064B1 (en) | Porosity carbon-silicon composite microspheres for anode active material, Manufacturing method thereof and lithium secondary battery comprising the same | |
| JP5673545B2 (en) | Lithium ion secondary battery negative electrode and lithium ion secondary battery | |
| CN108963187B (en) | Silicon-carbon cathode, preparation method thereof, lithium ion battery and electric vehicle | |
| US20110163274A1 (en) | Electrode composite, battery electrode formed from said composite, and lithium battery comprising such an electrode | |
| TWI725822B (en) | Lithium battery and anode material thereof | |
| JP7472972B2 (en) | Negative electrode material for lithium-ion secondary batteries and its applications | |
| JP2010501970A (en) | Silicon / carbon composite cathode material for lithium ion battery and method for producing the same | |
| TWI686001B (en) | Polymer-modified silicon-carbon composite and use thereof | |
| KR20190143661A (en) | Silicon-encapsulated carbon composite material for secondary battery anode material and manufacturing method thereof | |
| CN113690427A (en) | Preparation method of lithium-silicon alloy pole piece, lithium-silicon alloy pole piece and lithium battery | |
| EP4379865A1 (en) | Two-element lithium supplementing additive, preparation method therefor, and use thereof | |
| US20160248081A1 (en) | Electrode for electrical energy storage batteries comprising a graphite/silicon/carbon fiber composite material | |
| CN113871574B (en) | Lithium ion battery negative plate and preparation method and application thereof | |
| CN113921756B (en) | Silicon-carbon negative electrode piece with high silicon content and preparation method thereof | |
| CN114914444B (en) | Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery | |
| CN116544371A (en) | Positive electrode material, sodium ion battery and electric equipment | |
| CN116936741A (en) | Silicon-carbon negative electrode piece, preparation method thereof and lithium ion battery | |
| CN112635723B (en) | Lithium ion battery negative electrode active material, lithium ion battery negative electrode and lithium ion battery | |
| KR102590699B1 (en) | Non-oxidation carbon nanotube dispersion solution by mechanical impregnation method and non-oxidation carbon nanotube | |
| CN115621430A (en) | Modified silicon-carbon negative electrode slurry, preparation method thereof and lithium ion battery | |
| CN116102081B (en) | Positive electrode active material precursor, preparation method thereof and positive electrode active material | |
| WO2023201775A1 (en) | Negative electrode material and preparation method therefor, and lithium ion battery | |
| JP6871436B2 (en) | Electrodes, lithium-ion secondary batteries, electrode manufacturing methods and lithium-ion secondary battery manufacturing methods | |
| WO2014098007A1 (en) | Electrode material, electricity storage device provided with electrode material, and method for producing electrode material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |