WO2023208058A1 - Negative electrode sheet, preparation method therefor, battery, and preparation method for negative electrode material - Google Patents
Negative electrode sheet, preparation method therefor, battery, and preparation method for negative electrode material Download PDFInfo
- Publication number
- WO2023208058A1 WO2023208058A1 PCT/CN2023/090928 CN2023090928W WO2023208058A1 WO 2023208058 A1 WO2023208058 A1 WO 2023208058A1 CN 2023090928 W CN2023090928 W CN 2023090928W WO 2023208058 A1 WO2023208058 A1 WO 2023208058A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- negative electrode
- silicon
- carbon
- active material
- tin
- Prior art date
Links
- 239000007773 negative electrode material Substances 0.000 title claims abstract description 66
- 238000002360 preparation method Methods 0.000 title abstract description 21
- 239000011149 active material Substances 0.000 claims abstract description 89
- 239000002210 silicon-based material Substances 0.000 claims abstract description 69
- 238000000034 method Methods 0.000 claims abstract description 22
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims abstract description 16
- 239000000377 silicon dioxide Substances 0.000 claims abstract 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 211
- 229910052799 carbon Inorganic materials 0.000 claims description 143
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 124
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 103
- 229910052710 silicon Inorganic materials 0.000 claims description 102
- 239000010703 silicon Substances 0.000 claims description 102
- 239000002070 nanowire Substances 0.000 claims description 92
- 239000002135 nanosheet Substances 0.000 claims description 79
- 239000002041 carbon nanotube Substances 0.000 claims description 64
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 64
- 239000010410 layer Substances 0.000 claims description 48
- 239000007789 gas Substances 0.000 claims description 21
- 238000005245 sintering Methods 0.000 claims description 21
- 238000002156 mixing Methods 0.000 claims description 19
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 19
- 229910001887 tin oxide Inorganic materials 0.000 claims description 19
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 18
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 claims description 18
- 238000005087 graphitization Methods 0.000 claims description 18
- 238000003756 stirring Methods 0.000 claims description 17
- 239000013078 crystal Substances 0.000 claims description 15
- 239000011230 binding agent Substances 0.000 claims description 14
- 239000006258 conductive agent Substances 0.000 claims description 13
- 229910000676 Si alloy Inorganic materials 0.000 claims description 12
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 claims description 11
- 239000002105 nanoparticle Substances 0.000 claims description 11
- 239000011247 coating layer Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 239000002243 precursor Substances 0.000 claims description 10
- 239000002002 slurry Substances 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 8
- 239000002131 composite material Substances 0.000 claims description 7
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 6
- 230000008021 deposition Effects 0.000 claims description 6
- 229910001416 lithium ion Inorganic materials 0.000 claims description 6
- 230000002195 synergetic effect Effects 0.000 claims description 6
- 239000002109 single walled nanotube Substances 0.000 claims description 5
- 239000012298 atmosphere Substances 0.000 claims description 4
- 238000011065 in-situ storage Methods 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- 230000009467 reduction Effects 0.000 claims description 3
- 238000012986 modification Methods 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims description 2
- 239000002052 molecular layer Substances 0.000 claims description 2
- 238000007600 charging Methods 0.000 abstract description 16
- 230000008569 process Effects 0.000 abstract description 15
- 238000007599 discharging Methods 0.000 abstract description 7
- 230000008859 change Effects 0.000 abstract description 4
- 230000000052 comparative effect Effects 0.000 description 20
- 230000014759 maintenance of location Effects 0.000 description 14
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 11
- 238000002441 X-ray diffraction Methods 0.000 description 11
- 238000005520 cutting process Methods 0.000 description 11
- 229910052744 lithium Inorganic materials 0.000 description 11
- 239000000126 substance Substances 0.000 description 11
- 239000002699 waste material Substances 0.000 description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- 239000004576 sand Substances 0.000 description 8
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000005096 rolling process Methods 0.000 description 7
- 229910052814 silicon oxide Inorganic materials 0.000 description 7
- 238000003780 insertion Methods 0.000 description 6
- 230000037431 insertion Effects 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- -1 and at the same time Chemical compound 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000010405 anode material Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 239000011889 copper foil Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000005543 nano-size silicon particle Substances 0.000 description 4
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 4
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 4
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000001768 carboxy methyl cellulose Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000012299 nitrogen atmosphere Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 229920002125 Sokalan® Polymers 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 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 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- GJEAMHAFPYZYDE-UHFFFAOYSA-N [C].[S] Chemical compound [C].[S] GJEAMHAFPYZYDE-UHFFFAOYSA-N 0.000 description 1
- 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 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000002048 multi walled nanotube Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 239000011863 silicon-based powder Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000010413 sodium alginate Nutrition 0.000 description 1
- 239000000661 sodium alginate Substances 0.000 description 1
- 229940005550 sodium alginate Drugs 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- H01M4/13—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
- 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
- H01M4/139—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
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/626—Metals
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present application relates to the technical field of secondary batteries, and in particular to a negative electrode plate and a preparation method thereof, a battery, and a preparation method of negative electrode materials.
- lithium-ion batteries Due to the rapid development and widespread application of portable electronic devices and electric vehicles, there is an urgent need for lithium-ion batteries with high specific energy and long cycle life.
- commercialized lithium-ion batteries mainly use graphite as the negative electrode material.
- the theoretical specific capacity of graphite is only 372mAh/g, which limits the further improvement of the specific energy of lithium-ion batteries.
- the theoretical specific capacity of silicon can reach up to 4200mAh/g. However, the volume of silicon expands by more than 300% during the lithium storage process, resulting in a decrease in performance.
- the purpose of the embodiments of the present application includes providing a negative electrode plate and a preparation method thereof, a battery, and a preparation method of negative electrode materials, so as to reduce the impact of the expansion of the sheet-like silicon-based material on battery performance.
- embodiments of the present application provide a negative electrode sheet, including a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector.
- the active material in the negative active material layer includes sheet-shaped silicon-based material, and based on the surface of the negative electrode current collector, at least 60% of the sheet-shaped silicon-based material has an angle of ⁇ 20° with the surface of the negative electrode current collector.
- the angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector is ⁇ 20°.
- the sheet-shaped silicon-based material tends to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode plate, the sheet-shaped silicon-based material tends to Arranged in parallel and forming a stacked structure, the structure can be made more stable; during the charging and discharging process, the volume of the sheet-like silicon-based material changes and slides along the thickness direction, which can fill the gaps inside the negative electrode plate, making the electrode plate have good of electrical contact and integrity, the battery performs better.
- the sheet-like silicon-based materials are silicon nanosheets, silicon submicron sheets, silicon alloy nanosheets, silicon alloy submicron sheets, silicon-oxygen nanosheets, silicon-oxygen submicron sheets and their surface modifications One or more materials after coating.
- the silicon nanosheet has a thickness of 1-200 nm and a planar size of 20-5000 nm.
- the active material may also include carbon-coated tin nanowires as a synergistic active material.
- the diameter of the carbon-coated tin nanowire is below 100 nm, and the aspect ratio is (5-1000):1.
- carbon-coated tin nanowires are formed by in-situ reduction of tin oxide nanoparticles and carbon deposition.
- the active material further includes carbon nanotubes as synergistic active materials.
- the diameter of the carbon nanotube is less than 20 nm, and the aspect ratio is (10-1000):1.
- the carbon nanotubes include at least single-walled carbon nanotubes.
- the sum of the masses of active material, conductive agent and binder is the total mass, the mass of active material accounts for 70%-95% of the total mass, and the mass of conductive agent accounts for 70%-95% of the total mass. It is 0%-10%, and the binder mass accounts for 2%-30% of the total mass.
- the weight percentage of silicon is 70%-98%
- the weight percentage of tin is 0.5%-20%
- the weight percentage of carbon is 1.5-20%.
- embodiments of the present application provide a lithium ion secondary battery, including the above-mentioned negative electrode plate.
- embodiments of the present application provide a solid-state battery, including the above-mentioned negative electrode plate.
- embodiments of the present application provide a method for preparing an anode material, which includes: dispersing a carbon nanotube solution, a silicon-based material, and tin oxide nanoparticles in an organic solvent, grinding, filtering, and drying to obtain a composite precursor.
- the composite precursor is placed in a high-temperature sintering furnace, heated to 650-900°C in an inert atmosphere, and then acetylene gas is introduced for sintering to obtain a mixture of carbon nanotubes, carbon-coated tin nanowires and sheet-like silicon-based materials. negative electrode material.
- this application provides a method for preparing a negative electrode sheet, which includes mixing sheet silicon-based materials, conductive agents, binders and solvents in a stirring tank, and then using a stirrer in the stirring tank at 200-3000rad. /min, and the mixing tank itself is continuously rotated at a speed of 200-3000rad/min to obtain the negative active slurry. Then, the negative electrode active slurry is coated on the surface of the negative electrode current collector, dried, and rolled to obtain a negative electrode piece.
- the angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector can be ⁇ 20°.
- the sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets
- the volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
- Figure 1 is a scanning electron microscope (SEM) image of the negative electrode piece (original electrode piece) provided in Example 1 of the present application;
- Figure 2 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth cycle of lithium insertion state) provided in Example 1 of the present application;
- Figure 3 is a scanning electron microscope (SEM) image of the negative electrode piece (original electrode piece) provided in Comparative Example 1;
- Figure 4 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth week of lithium insertion state) provided in Comparative Example 1;
- Figure 5 is an X-ray diffraction (XRD) pattern of the active material provided in Example 1 of the present application;
- Figure 6 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the present application before rolling;
- Figure 7 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the present application after rolling;
- Figure 8 is a charge-discharge curve of the half-cell provided in Embodiment 1 of the present application.
- Figure 9 is a scanning electron microscope (SEM) image of the negative active material provided in Example 1 of the present application.
- Figure 10 is a scanning electron microscope (SEM) image of the negative active material provided in Example 9 of the present application.
- Figure 11 is a scanning electron microscope (SEM) image of the negative active material of the battery provided in Example 1 of the present application after 5 weeks of cycling;
- Figure 12 is a scanning electron microscope (SEM) image of the negative active material provided in Comparative Example 3;
- Figure 13 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 1 of the present application;
- Figure 14 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 10 of the present application;
- Figure 15 is an impedance diagram of the battery provided in Example 1 and Example 9 of the present application.
- Figure 16 is a cycle performance diagram of the battery provided in Example 1 of the present application under 2C conditions.
- Embodiments of the present application provide a negative electrode sheet, which includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector.
- the negative active material layer includes active material, conductive agent and binder.
- the sum of the masses of the active material, conductive agent and binder is the total mass, the mass of the active material accounts for 70%-95% of the total mass, and the mass of the conductive agent accounts for 0%-10% of the total mass. %, the binder mass accounts for 5%-30% of the total mass.
- the density, specific capacity and first charge of the negative active material layer can be improved.
- the mass percentage of the active material to the total mass is 70%, 75%, 80%, 85%, 90% or 95%; the mass percentage of the conductive agent to the total mass is 0%, 2%, 4%, 6%, 8% or 10%; the percentage of binder mass to the total mass is 2%, 10%, 15%, 20%, 25% or 30%.
- the conductive agent can be one or more combinations of conductive carbon black, conductive graphite, conductive carbon fiber, carbon nanotubes and graphene;
- the binder can be carboxymethylcellulose, styrene-butadiene rubber, polyacrylic acid, polyacrylic acid One or a combination of sodium, lithium polyacrylate, sodium alginate, and polyvinylidene fluoride.
- the active material includes sheet-shaped silicon-based material.
- Sheet-like silicon-based materials refer to silicon-based materials that contain silicon and can deintercalate lithium; the silicon-based materials are in the form of sheets, and the thickness of the sheet-like materials is at the nanometer level.
- the flaky silicon-based material is silicon nanosheets (silicon elemental substance), silicon submicron flakes (silicon elemental substance), silicon alloy nanosheets (silicon alloy), silicon alloy submicron flakes (silicon alloy), silicon oxygen nanosheets (Silicon-oxygen material SO x , 0 ⁇ x ⁇ 2) and silicon-oxygen submicron sheets (silica-oxygen material SO x , 0 ⁇ x ⁇ 2) and one or more of their surface-modified and coated materials.
- silicon nanosheets refer to: silicon element is in the form of a sheet, and the thickness of the silicon sheet is at the nanometer level.
- the silicon nanosheet has a thickness of 1-100nm and a planar size of 20-5000nm.
- the thickness of the silicon nanosheet refers to: the maximum distance between the two surfaces of the silicon nanosheet; the plane size of the silicon nanosheet refers to: in the outline of the projection of the sheet-like structure of the silicon nanosheet on the horizontal plane, The distance between the two furthest points.
- the thickness of silicon nanosheets is 1nm, 5nm, 10nm, 20nm, 40nm, 60nm, 80nm or 100nm;
- the plane size of silicon nanosheets is 20nm, 50nm, 100nm, 200nm, 400nm, 600nm, 800nm, 1000nm, 1200nm, 1400nm , 1600nm, 1800nm or 2000nm.
- the surface of the silicon nanosheet is also coated with a carbon layer with a thickness of nanometer level.
- the thin carbon layer can maintain a high specific capacity of the active material; on the other hand, the coating of the carbon layer can avoid direct contact between the flaky silicon-based material and the electrolyte to a certain extent, and the active material The cycle stability of the material is further improved.
- the thickness of the carbon coating layer on the sheet-shaped silicon-based material is 2-10 nm.
- the angle between at least 60% of the sheet-shaped silicon-based materials and the surface of the negative electrode current collector is ⁇ 20°; that is, based on the plane direction of the negative electrode current collector, at least The tilt angle between 60% of the sheet silicon-based material and the negative electrode current collector is ⁇ 20°.
- the sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets
- the volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
- the angle between two adjacent pieces of silicon-based material is ⁇ 10°.
- the distribution of sheet-like silicon-based materials on the negative electrode current collector can be made more consistent, so that more sheet-like silicon-based materials can exist in a stacked form to improve battery performance.
- the angle between at least 90% of the sheet-like silicon-based materials and the surface of the negative electrode current collector is ⁇ 20°; and along the thickness direction of the negative electrode plate, the angle between two adjacent pieces of sheet-like silicon-based materials is ⁇ 5 °. More sheet-like silicon-based materials are basically parallel to the negative electrode current collector and form a stacked structure, which can make the battery perform better.
- the angle between all the sheet-shaped silicon-based materials and the surface of the negative electrode current collector is ⁇ 20°. All flaky silicon-based materials basically tend to be parallel to the negative current collector, resulting in better battery performance.
- the active material also includes carbon-coated tin nanowires as synergistic active materials.
- Carbon-coated tin nanowires refer to: the surface of the tin nanowires is coated with a carbon layer, and the carbon-coated tin nanowires formed are still linear structures, and their sizes are also nanoscale.
- the tin material itself has good electrical conductivity and ionic conductivity. When combined with the coating carbon layer, it has rapid charge and discharge capabilities; and the coating of the carbon layer can keep its structure intact during the charge and discharge process and achieve good performance. electrical contact.
- the thickness of the carbon coating layer in the carbon-coated tin nanowire is nanoscale.
- the thickness of the carbon coating layer on the carbon-coated tin nanowire is 2-10 nm.
- the diameter of the carbon-coated tin nanowire is below 100nm, and the aspect ratio is (5-1000):1.
- the diameters of different parts of the carbon-coated tin nanowires can be the same or different.
- the diameter is below 100nm and the aspect ratio is (5-1000):1, which can make it more flexible.
- After mixing the flaky silicon-based materials can form a three-dimensional network structure with flaky silicon-based materials, which can avoid the volume expansion of flaky silicon-based materials to a certain extent.
- the aspect ratio of the carbon-coated tin nanowire is 5:1, 10:1, 20:1, 40:1, 80:1, 160:1, 320:1, 480:1, 600:1 Or 1000:1.
- carbon-coated tin nanowires are formed by in-situ reduction of tin oxide nanoparticles and carbon deposition.
- reducing gas for example, acetylene gas
- tin oxide is reduced to tin while using tin as a catalyst to obtain carbon-coated tin nanowires with a carbon layer evenly deposited on the surface of the tin nanowires, and the tin nanowires are
- the carbon layer is uniformly deposited on the surface of the wire, and the carbon layer is more closely combined with the tin nanowire.
- the carbon layer has a high degree of graphitization, which is beneficial to improving the performance of the negative electrode material.
- reducing gas for example, acetylene gas
- tin oxide is reduced to tin while using tin as a catalyst to obtain carbon-coated tin nanowires with a carbon layer evenly deposited on the surface of the tin nanowires, and the tin nanowires are The carbon layer is uniformly deposited on the surface of the wire, and the carbon layer is more closely combined with the tin nanowire.
- the graphitization degree of the carbon layer is high, which can make the graphitization degree of the carbon layer in the carbon-coated tin nanowire be between 0.3-1. , its graphitization degree is high, which is beneficial to improving the performance of negative electrode materials.
- the graphitization degree ⁇ of the carbon coating layer in the carbon-coated tin nanowire is 0.3-0.6 or 0.6-1; as an example, the graphitization degree ⁇ of the carbon coating layer in the carbon-coated tin nanowire is is 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.
- the active material also includes carbon nanotubes as synergistic active materials.
- Carbon nanotubes refer to carbon materials that are in the form of tubes, and the outer diameter of the carbon tubes is nanoscale.
- the diameter of carbon nanotubes is below 20nm, and the aspect ratio is (10-1000):1.
- the diameters of different parts of carbon nanotubes can be similar The same or different, the diameter is below 20nm and the aspect ratio is (10-1000):1. Since both carbon-coated tin nanowires and carbon nanotubes have a certain degree of elasticity and flexibility, when mixed with sheet-like silicon-based materials, a better three-dimensional conductive network can be formed, which can alleviate the volume effect of lithium deintercalation in the negative electrode. , making the battery have a larger specific capacity and higher cycle stability; at the same time, the negative electrode plate has good ionic conductivity and electronic conductivity, and better conductivity.
- the carbon nanotubes include at least single-walled carbon nanotubes. It can make the performance of the negative electrode piece better.
- the carbon nanotubes may also be a mixture of single-walled carbon nanotubes and multi-walled carbon nanotubes.
- the weight percentage of silicon is 70%-98%, the weight percentage of tin is 0.5%-20%, and the weight percentage of carbon is 1.5-20%.
- the weight percentage of silicon, tin and carbon refers to the element content.
- the weight percentage of carbon refers to the sum of the weight percentage of carbon in carbon-coated tin nanowires and carbon in carbon nanotubes;
- the weight percentage of silicon refers to the weight percentage of silicon in the sheet-shaped silicon-based material;
- the weight percentage of tin refers to the weight percentage of tin in the carbon-coated tin nanowires.
- the weight percentage of silicon is 70%, 74%, 78%, 82%, 86%, 90%, 94% or 98%; the weight percentage of tin is 0.5%, 1%, 2%, 4 %, 8%, 12%, 16% or 20%; carbon weight percentage is 1.5%, 3%, 5%, 8%, 10%, 12%, 14%, 16%, 18% or 20% .
- the single-surface density of the negative electrode piece provided by this application is 1-40 mg/cm 2 . It can be used to prepare secondary batteries, such as lithium-ion batteries or all-solid-state batteries. It can make the battery have a specific capacity of 1000-3000mAh/g and a first charge and discharge Coulombic efficiency of ⁇ 80% to improve battery performance.
- the negative active material including flake silicon-based material
- conductive agent including flake silicon-based material
- binder and solvent
- the stirrer in the stirring tank operates at a speed of 200-3000rad/min.
- the mixing tank itself continuously rotates at a speed of 200-3000rad/min to obtain the negative electrode active slurry.
- the negative electrode active slurry is coated on the surface of the negative electrode current collector, dried, and rolled to obtain a negative electrode piece.
- the angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector can be ⁇ 20°.
- the sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets
- the volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
- the rotation speed of the agitator can be 200-1000rad/min or 1000-3000rad/min
- the rotation speed of the mixing tank itself can be 200-1000rad/min or 1000-3000rad/min.
- the rotation speed of the stirrer and the stirring tank can be independently selected from 200rad/min, 500rad/min, 1000rad/min, 1500rad/min, 2000rad/min, 2500rad/min or 3000rad/min.
- the preparation method of the negative active material can be: dispersing the carbon nanotube solution, silicon-based material, and tin oxide nanoparticles in an organic solvent, grinding (such as ball milling, sand milling, etc.), filtering, and drying to obtain a composite precursor.
- the composite precursor is placed in a high-temperature sintering furnace, heated to 650-900°C in an inert atmosphere, and then acetylene gas is introduced for sintering to obtain a mixture of carbon nanotubes, carbon-coated tin nanowires and sheet-like silicon-based materials. negative electrode material.
- the preparation method of the negative active material can also be: put the tin oxide nanoparticles into a high-temperature sintering furnace, raise the temperature to 650-900°C in an inert atmosphere, and introduce acetylene gas for sintering. After sintering, carbon-coated tin can be obtained Nanowires.
- the carbon nanotube solution, flaky silicon-based material, and carbon-coated tin nanowires are dispersed in an organic solvent, filtered, and dried to obtain a negative electrode material mixed with carbon nanotubes, carbon-coated tin nanowires, and flaky silicon-based materials.
- tin oxide can be reduced to tin, and at the same time, tin can be used as a catalyst for the deposition of acetylene gas, which can uniformly deposit a carbon layer on the surface of the tin nanowires, and the carbon layer and the tin The nanowires are more tightly bonded, and the carbon layer has a high degree of graphitization in carbon-coated tin nanowires.
- Carbon nanotubes, carbon-coated tin nanowires, and flaky silicon-based materials are mixed in a solvent to obtain a uniformly mixed anode material; at the same time, the three form a three-dimensional network structure to a certain extent, making the anode material have a higher Good ionic conductivity and electronic conductivity make the negative electrode material perform better.
- the sintering temperature may be 650-750°C or 750-900°C; as an example, the sintering temperature may be 650°C, 700°C, 750°C, 800°C, 850°C or 900°C.
- the carbon nanotubes are dispersed in an ethanol solvent to obtain a carbon nanotube solution, where the mass ratio of the carbon nanotubes to ethanol is 1:100.
- the active material includes silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon nanosheets is coated with a carbon layer.
- the thickness of silicon nanosheets is 10-80nm, and the planar size is 200-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1.
- silicon accounts for 86.6wt% of the active material; tin accounts for 4.6wt% of the active material; carbon accounts for 5.2wt% of the active material; and other substances account for 3.1wt% of the active material.
- the agitator in the mixing tank continuously stirs at a speed of 500 rad/min, and the mixing tank itself continuously rotates at a speed of 500 rad/min to obtain the negative active material slurry.
- the negative active material slurry is coated on the surface of the copper foil with a scraper, and then dried to obtain a negative electrode piece.
- the negative electrode piece is rolled, and a punch is used to prepare a small round piece with a diameter of 15 mm from the rolled negative electrode piece.
- the above-mentioned negative electrode sheet and lithium sheet are paired and assembled into a button half battery.
- the battery assembly process is carried out in a glove box filled with argon gas.
- Celgard2300 membrane is used as the isolation membrane, and the electrolyte is a solution of 1 mol/L LiPF 6 dissolved in EC:DMC:FEC (volume ratio 4.8:4.8:0.4).
- Example 2 The difference between Example 2 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with silicon oxide with a particle size of 5-10 ⁇ m.
- the active material includes silicon oxide nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon oxide nanosheets is coated with a carbon layer.
- the thickness of silicon oxide nanosheets is 50-80nm, and the planar size is 200-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500): 1; the diameter of carbon nanotubes is 10-20nm, aspect ratio is (100-200):1.
- silicon accounts for 60.8wt% of active materials; oxygen accounts for 29.3wt% of active materials; tin accounts for 4.6wt% of active materials; carbon accounts for 4.8wt% of active materials; other substances account for 0.5% of active materials. wt%.
- Example 3 The difference between Example 3 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with ferrosilicon alloy with a particle size of 5-10 ⁇ m.
- the active material includes ferrosilicon alloy nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the ferrosilicon alloy nanosheets is coated with a carbon layer.
- the thickness of ferrosilicon alloy nanosheets is 20-60nm, and the planar size is 100-500nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10 -20nm, aspect ratio is (100-200):1.
- silicon accounts for 76.3wt% of active materials; iron accounts for 12.1wt% of active materials, tin accounts for 3.5wt% of active materials; carbon accounts for 7.6wt% of active materials; other substances account for 0.5% of active materials. wt%.
- Embodiment 4 The difference between Embodiment 4 and Embodiment 1 is that in step (1), the solar silicon wafer cutting waste is replaced with silicon nanosheets with a thickness of 10-50nm and a planar size of 100-600nm, and does not need to be sanded in a sand mill. grind.
- the active materials include silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes.
- the thickness of silicon nanosheets is 10-50nm, and the planar size is 100-600nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1.
- silicon accounts for 87.6wt% of the active material; tin accounts for 4.3wt% of the active material; carbon accounts for 7.8wt% of the active material; and other substances account for 0.3wt% of the active material.
- Embodiment 5 The difference between Embodiment 5 and Embodiment 1 is that in step (2), the solar silicon wafer cutting waste is replaced with silicon oxide nanosheets with a thickness of 50-100nm and a planar size of 100-800nm. There is no need to use a sand mill. Medium sanding.
- the active materials include silicon oxide nanosheets, carbon-coated tin nanowires and carbon nanotubes.
- the thickness of silicon oxide nanosheets is 50-100nm, and the planar size is 100-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10-20nm, aspect ratio is (100-200):1.
- silicon accounts for 61.2wt% of the active material; oxygen accounts for 28.5wt% of the active material; tin accounts for 3.6wt% of the active material; carbon accounts for 4.2wt% of the active material; other substances account for 3.1wt of the active material. %.
- Embodiment 5 The difference between Embodiment 5 and Embodiment 1 is that: in step (2), the solar silicon wafer cutting waste is replaced with ferrosilicon alloy nanosheets with a thickness of 50-80nm and a planar size of 200-600nm, and does not need to be used in a sand mill. Sanding.
- the active materials include ferrosilicon alloy nanosheets, carbon-coated tin nanowires and carbon nanotubes.
- the thickness of ferrosilicon alloy nanosheets is 50-80nm, and the planar size is 200-600nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10 -20nm, aspect ratio is (100-200):1.
- silicon accounts for 74.6wt% of active materials; iron accounts for 11.5wt% of active materials, tin accounts for 3.2wt% of active materials; carbon accounts for 7.6wt% of active materials; other substances account for 2.1% of active materials. wt%.
- Example 7 The difference between Example 7 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with single crystal silicon with a particle size of 5-10 ⁇ m.
- the active material includes silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon nanosheets is coated with a carbon layer.
- the thickness of silicon nanosheets is 50-100nm, and the planar size is 200-1000nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1.
- silicon accounts for 84.6wt% of the active material; tin accounts for 5.1wt% of the active material; carbon accounts for 6.9wt% of the active material; and other substances account for 3.4wt% of the active material.
- Example 8 The difference between Example 8 and Example 1 is that no carbon nanotubes and tin oxide are added.
- the active material includes silicon nanosheets, and the surface of the silicon nanosheets is coated with a carbon layer.
- the thickness of silicon nanosheets is 10-80nm, and the plane size is 200-800nm; in terms of weight percentage, silicon accounts for 94.6wt% of the active material; tin accounts for 0wt% of the active material; carbon accounts for 4.2wt% of the active material; Other substances account for 1.2 wt% of the active material.
- Example 9 The difference between Example 9 and Example 1 is that the preparation method of the negative electrode material is:
- the carbon nanotubes are dispersed in an ethanol solvent to obtain a carbon nanotube solution, where the mass ratio of the carbon nanotubes to ethanol is 1:100.
- Example 10 The difference between Example 10 and Example 9 is that the preparation method of carbon-coated tin nanowires is: placing the tin nanowires in an N-methylpyrrolidone solution containing polytetrafluoroethylene, and after dispersing, the tin nanowires are coated on the surface. Covered with an adhesive layer; filter and dry to obtain the precursor. The precursor is put into a high-temperature sintering furnace and sintered and carbonized under a nitrogen atmosphere from room temperature to 700°C. After sintering, carbon-coated tin nanowires can be obtained.
- Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the solar silicon wafer cutting waste is replaced with silicon powder with a diameter of 80-100 nm, and silicon nanosheets cannot be formed.
- the active material does not have silicon nanosheets, only silicon nanoparticles with a diameter of 80-100nm, and the silicon surface is coated with a carbon layer.
- the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10-20nm, and the aspect ratio is (100-200). ):1.
- silicon accounts for 84.3wt% of the active material; tin accounts for 5.3wt% of the active material; carbon accounts for 5.7wt% of the active material; and other substances account for 3.7wt% of the active material.
- the size of the silicon-based nanosheets, the size of the carbon-coated tin nanowires, the size of the carbon nanotubes, and the arrangement of the silicon-based nanosheets were all observed through scanning electron microscopy (SEM) images.
- Figure 1 is a scanning electron microscope (SEM) image of the negative pole piece (original pole piece) provided in Example 1 of the present application. Please refer to Figure 1. There are some gaps inside the original pole piece, and the pole piece has a certain porosity. Silicon nanoparticles There is a linear structure between the sheets, and the silicon nanosheets tend to be arranged in parallel to form a stacked structure, and they also tend to be arranged in parallel in the direction of the current collector.
- Figure 2 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth cycle of lithium insertion state) provided in Example 1 of the present application. Please refer to Figure 2.
- SEM scanning electron microscope
- Figure 3 is a scanning electron microscope (SEM) image of the negative pole piece (original pole piece) provided in Comparative Example 1. Please refer to Figure 3. There are some gaps inside the original pole piece, and the pole piece has a certain porosity. Among the silicon nanosheets There is a linear structure between them, and the silicon nanosheets are arranged irregularly.
- Figure 4 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth week of lithium insertion state) provided in Comparative Example 1. Please refer to Figure 4. Since the silicon nanosheets are irregularly arranged, during the lithium insertion process, the silicon nanosheets move along the Volume changes and sliding occur in the thickness direction, which cannot fill the internal gaps of the pole piece, and are randomly distributed in the active material layer.
- SEM scanning electron microscope
- Figure 5 is an X-ray diffraction (XRD) pattern of the active material provided in Example 1 of the application.
- Figure 6 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the application before rolling.
- Figure 7 is The X-ray diffraction (XRD) pattern of the negative electrode sheet after rolling provided in Example 1 of the present application.
- XRD X-ray diffraction
- a layer of PVDF is first coated on the copper foil during the coating process. When testing XRD, the copper foil is first removed.
- the values of the (111)/(220) crystal plane peak intensity and the (111)/(311) crystal plane peak intensity of the rolled pole piece both increase, indicating that the rolled pole piece has better performance. Silicon
- the angle between the nanosheets and the negative electrode current collector is small, and the silicon nanosheets tend to be parallel to the negative electrode current collector.
- Figure 8 is a charge-discharge curve of the half-cell provided in Embodiment 1 of the present application. It can be seen from Figure 8 that the first-cycle capacity of the half-cell provided in Embodiment 1 is as high as 3000 mAh/g, and the first-cycle Coulombic efficiency is as high as 90%.
- Figure 9 is a scanning electron microscope (SEM) picture of the negative active material provided in Example 1 of the present application.
- Figure 10 is a scanning electron microscope (SEM) picture of the negative active material provided in Example 9 of the present application.
- Figure 11 is a SEM picture of the negative active material provided in Example 1 of the present application.
- a scanning electron microscope (SEM) image of the negative electrode active material after 5 weeks of battery cycling is provided.
- FIG. 12 is a scanning electron microscope (SEM) image of the negative electrode active material provided in Comparative Example 3.
- the carbon-coated tin nanowires, silicon nanosheets and carbon nanotubes in the negative active materials of Examples 1 and 9 are mixed to form a three-dimensional network structure, and the negative electrode in Figure 9
- the carbon-coated tin nanowires and carbon nanotubes of the active materials can be more evenly dispersed on the surface of the silicon nanosheets to form a three-dimensional ion conductive network structure on the surface of the silicon nanosheets; at the same time, in the negative active material provided in Figure 9, by oxidizing Tin nanoparticles are evenly dispersed on the surface of silicon nanosheets, and then carbon-coated tin nanowires are reduced and uniformly grown in situ, which can compensate for the particle conductivity of silicon, and combine carbon nanotubes and silicon nanosheets to form a three-dimensional conductive network to make the negative electrode active.
- Figure 13 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 1 of the application
- Figure 14 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 10 of the application.
- TEM transmission electron microscope
- the microstructure of the carbon layer coated on the surface of the tin nanowires in Example 1 is a parallel linear structure, and the distance between two adjacent linear structures is d 002 The value is 0.33564.
- Figure 15 is an impedance diagram of the battery provided in Example 1 and Example 9 of the present application. It can be seen from Figure 15 that the impedance of the battery prepared from the negative active material provided in Example 9 is the same as that prepared from the negative active material provided in Example 1. The resistance of the obtained battery is 2.5 times, indicating that the negative active material provided in Example 1 has more excellent conductivity.
- Figure 16 is a cycle performance diagram of the battery provided in Example 1 of the present application under 2C conditions. It can be seen from Figure 16 that the embodiment of this application 1The battery provided can cycle stably for 1000 cycles, and the capacity can be stabilized at 700mAh/g.
- the cycle capacity retention rate of 100 cycles the charging capacity of the 100th cycle / the charging capacity of the first week ⁇ 100%.
- Volume expansion rate in the first week Use a micrometer to measure the original pole piece thickness h1 and the thickness h2 of the fully lithium-embedded pole piece in the first week.
- the charging specific capacity in the first week, Coulombic efficiency in the first week, Coulombic efficiency in the 100th week and cycle capacity retention rate data in the 100th week of each embodiment and comparative example are shown in Table 2.
- the half-battery prepared using the negative electrode sheet provided in the embodiment of the present application has a charging capacity greater than 1500 mAh/g in the first week, a cycle retention rate greater than 90% after 100 weeks, and a volume expansion rate in the first week. Both are less than 130%, indicating better overall performance.
- the volume expansion rate of the half-battery prepared using the negative electrode sheet provided in the comparative example is very high, and the cycle retention rate is low.
- Example 9 Comparing Example 1 and Example 9, it can be seen that after the battery is prepared from the negative active material provided in Example 1, its first-week charging capacity and cycle rate are The ring retention rates are all high, indicating that after mixing silicon nanosheets and carbon nanotubes with tin oxide particles, acetylene gas is introduced under high temperature conditions for reaction, and carbon-coated tin nanowires with a high degree of graphitization can be formed. , making the mixing of the three more uniform, and obtaining a negative active material with better performance.
- Example 9 Comparing Example 9 and Example 10, it can be seen that after the battery is prepared from the negative active material provided in Example 9, its first-week charging capacity and cycle retention rate are both higher. It shows that compared with Example 10 where the organic binder is directly carbonized on the surface of the tin nanowires to form a carbon layer, Example 9 can form carbon-coated tin nanowires with a higher degree of graphitization by passing acetylene gas under high temperature conditions. After subsequent mixing with silicon nanosheets and carbon nanotubes, the resulting negative active material has better performance.
- the capacity retention rate under different rates is calculated by the following formula.
- Rate capacity retention rate charging capacity at this rate/0.1C rate charging capacity ⁇ 100%.
- the capacity retention rate of the half-battery prepared using the negative electrode sheet provided in the embodiment of the present application is greater than 65% at 1C rate; while the half-battery prepared using the negative electrode sheet provided in the comparative example has a capacity retention rate of more than 65%.
- the capacity retention rate at 1C rate is basically less than 40%.
- Example 9 Comparing Example 1 and Example 9, it can be seen that after the negative active material provided in Example 1 is used to prepare a battery, its rate performance is better, indicating that after mixing silicon nanosheets and carbon nanotubes with tin oxide particles, they are introduced under high temperature conditions.
- the reaction of acetylene gas can form carbon-coated tin nanowires with a higher degree of graphitization and at the same time make the mixing of the three more uniform, resulting in a negative active material with better performance.
- Example 9 Comparing Example 9 and Example 10, it can be seen that after the negative active material provided in Example 9 is used to prepare a battery, its rate performance is better. It shows that compared with Example 10 where the organic binder is directly carbonized on the surface of the tin nanowires to form a carbon layer, Example 9 can form carbon-coated tin nanowires with a higher degree of graphitization by passing acetylene gas under high temperature conditions. After subsequent mixing with silicon nanosheets and carbon nanotubes, the resulting negative active material has better performance.
- Example 1 On the basis of Example 1, the ratio of solar silicon and tin, ball milling time, and silicon type were changed respectively, and other conditions remained unchanged.
- the active material was prepared according to the method of Example 1, and then the active material was prepared according to Example 1. Batteries No. 1-13 were prepared using the button half cell method, and the charge and discharge cycle performance of the batteries were tested according to the electrochemical performance testing method. The results are shown in Table 4.
- Table 5 shows the XRD patterns of the negative electrode sheet (the active material includes silicon nanosheets) before and after rolling and the raw materials provided in Example 1, and the XRD patterns of the negative electrode sheet (the active material includes silicon nanoparticles) before and after rolling and the raw materials provided in Comparative Example 3. analysis results.
- Example 1 The non-rolled and rolled pole pieces of Example 1 and Comparative Example 3 were tested by X-ray diffraction. The results showed that in Example 1, from raw materials to pole pieces produced and then rolled, (111)/ The (220) crystal plane peak intensity and the (111)/(311) crystal plane peak intensity ratio are gradually increasing, indicating that the nanosheets in the pole piece gradually tend to be arranged in parallel, corresponding to SEM, while in Comparative Example 3, from raw materials to After making the pole piece and then rolling it, the peak intensity ratio of (111)/(220) crystal plane and the peak intensity of (111)/(311) crystal plane remain basically unchanged.
Abstract
The present application relates to a negative electrode sheet, a preparation method therefor, a battery, and a preparation method for a negative electrode material, and belongs to the technical field of secondary batteries. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on the surface of the negative electrode current collector. An active material in the negative electrode active material layer comprises piece-shaped silicon-based materials, and using the surface of the negative electrode current collector as a reference, the included angle between at least 60% of the piece-shaped silica-based materials and the surface of the negative electrode current collector is ≤20°. The piece-shaped silicon-based materials of the negative electrode sheet tend to be parallel to the negative electrode current collector, and, in the thickness direction of the negative electrode sheet, the piece-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, making a structure more stable. During charging and discharging processes, the piece-shaped silicon-based materials have a volume change and slide in the thickness direction, so as to fill gaps in the negative electrode sheet, making the electrode sheet exhibit good electric contact and integrity, and achieving better battery performance.
Description
相关申请的交叉引用Cross-references to related applications
本申请要求于2022年04月26日提交于中国国家知识产权局的申请号为202210446207.6、名称为“负极极片及电池”的专利申请的优先权，以及于2023年04月24日提交于中国国家知识产权局的申请号为202310456477X、名称为“负极极片及其制备方法、电池、及负极材料的制备方法”的中国专利申请的权益，该两个专利申请的全部内容通过引用结合在本申请中。This application claims the priority of the patent application with application number 202210446207.6 and titled "Anode Plate and Battery" submitted to the State Intellectual Property Office of China on April 26, 2022, and submitted to China on April 24, 2023 The rights and interests of the Chinese patent application with the application number 202310456477X and titled "Anode Plate and Preparation Method, Battery, and Preparation Method of Anode Material" filed by the State Intellectual Property Office. The entire contents of these two patent applications are incorporated herein by reference. Applying.
本申请涉及二次电池技术领域，且特别涉及一种负极极片及其制备方法、电池、及负极材料的制备方法。The present application relates to the technical field of secondary batteries, and in particular to a negative electrode plate and a preparation method thereof, a battery, and a preparation method of negative electrode materials.
由于便携式电子设备和电动汽车的快速发展和广泛应用，对于高比能量、长循环寿命的锂离子电池的需求十分迫切。目前商品化使用的锂离子电池主要采用石墨作为负极材料，但是，石墨的理论比容量仅为372mAh/g，限制了锂离子电池比能量的进一步提高。Due to the rapid development and widespread application of portable electronic devices and electric vehicles, there is an urgent need for lithium-ion batteries with high specific energy and long cycle life. Currently commercialized lithium-ion batteries mainly use graphite as the negative electrode material. However, the theoretical specific capacity of graphite is only 372mAh/g, which limits the further improvement of the specific energy of lithium-ion batteries.
而硅的理论比容量最高可以达到4200mAh/g，但是，硅在储锂过程中体积膨胀超过300％，导致性能下降。The theoretical specific capacity of silicon can reach up to 4200mAh/g. However, the volume of silicon expands by more than 300% during the lithium storage process, resulting in a decrease in performance.
发明内容Contents of the invention
针对相关技术的不足，本申请实施例的目的包括提供一种负极极片及其制备方法、电池、及负极材料的制备方法，以降低片状硅基材料的膨胀对电池性能的影响。In view of the shortcomings of the related technology, the purpose of the embodiments of the present application includes providing a negative electrode plate and a preparation method thereof, a battery, and a preparation method of negative electrode materials, so as to reduce the impact of the expansion of the sheet-like silicon-based material on battery performance.
第一方面，本申请实施例提供了一种负极极片，包括负极集流体以及设置于负极集流体表面的负极活性材料层。负极活性材料层中的活性材料包括片状硅基材料，以负极集流体的表面为基准，至少60％的片状硅基材料与负极集流体的表面的夹角≤20°。In a first aspect, embodiments of the present application provide a negative electrode sheet, including a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector. The active material in the negative active material layer includes sheet-shaped silicon-based material, and based on the surface of the negative electrode current collector, at least 60% of the sheet-shaped silicon-based material has an angle of ≤20° with the surface of the negative electrode current collector.
至少60％的片状硅基材料与负极集流体的表面的夹角≤20°，片状硅基材料倾向于与负极集流体平行，且沿负极极片的厚度方向，片状硅基材料倾向于平行排列并形成堆叠结构，可以使结构更加稳定；在进行充放电过程中，片状硅基材料沿着厚度方向发生体积变化和滑动，可以填充负极极片内部的空隙，使极片具有良好的电接触和完整性，电池的性能更佳。The angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector is ≤20°. The sheet-shaped silicon-based material tends to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode plate, the sheet-shaped silicon-based material tends to Arranged in parallel and forming a stacked structure, the structure can be made more stable; during the charging and discharging process, the volume of the sheet-like silicon-based material changes and slides along the thickness direction, which can fill the gaps inside the negative electrode plate, making the electrode plate have good of electrical contact and integrity, the battery performs better.
在本申请的部分实施例中，片状硅基材料为硅纳米片、硅亚微米片、硅合金纳米片、硅合金亚微米片、硅氧纳米片和硅氧亚微米片及其表面改性包覆后的材料的一种或多种。In some embodiments of the present application, the sheet-like silicon-based materials are silicon nanosheets, silicon submicron sheets, silicon alloy nanosheets, silicon alloy submicron sheets, silicon-oxygen nanosheets, silicon-oxygen submicron sheets and their surface modifications One or more materials after coating.
在本申请的部分实施例中，硅纳米片的厚度1-200nm；平面尺寸为20-5000nm。In some embodiments of the present application, the silicon nanosheet has a thickness of 1-200 nm and a planar size of 20-5000 nm.
在本申请的部分实施例中，活性材料还可以包括碳包覆锡纳米线作为协同活性材料。In some embodiments of the present application, the active material may also include carbon-coated tin nanowires as a synergistic active material.
在本申请的部分实施例中，碳包覆锡纳米线的直径在100nm以下，长径比为(5-1000):1。In some embodiments of the present application, the diameter of the carbon-coated tin nanowire is below 100 nm, and the aspect ratio is (5-1000):1.
在本申请的部分实施例中，碳包覆锡纳米线是通过原位还原氧化锡纳米颗粒和碳沉积形成的。In some embodiments of the present application, carbon-coated tin nanowires are formed by in-situ reduction of tin oxide nanoparticles and carbon deposition.
在本申请的部分实施例中，碳包覆锡纳米线中碳包覆层的石墨化度γ满足0.3≦γ≦1，其中γ＝(0.344-d002)/(0.344-0.3354)，d002为碳包覆层在002晶面的纳米层间距。In some embodiments of the present application, the graphitization degree γ of the carbon coating layer in the carbon-coated tin nanowire satisfies 0.3≦γ≦1, where γ=(0.344-d002)/(0.344-0.3354), d002 is carbon The nanometer spacing of the cladding layer on the 002 crystal plane.
在本申请的部分实施例中，活性材料还包括碳纳米管作为协同活性材料。In some embodiments of the present application, the active material further includes carbon nanotubes as synergistic active materials.
在本申请的部分实施例中，碳纳米管的直径在20nm以下，长径比为(10-1000):1。In some embodiments of the present application, the diameter of the carbon nanotube is less than 20 nm, and the aspect ratio is (10-1000):1.
在本申请的部分实施例中，碳纳米管至少包括单壁碳纳米管。
In some embodiments of the present application, the carbon nanotubes include at least single-walled carbon nanotubes.
在本申请的部分实施例中，以活性材料、导电剂和粘结剂三者质量和为总质量，活性材料质量占总质量的百分数为70％-95％，导电剂质量占总质量的百分数为0％-10％，粘结剂质量占总质量的百分数为2％-30％。In some embodiments of the present application, the sum of the masses of active material, conductive agent and binder is the total mass, the mass of active material accounts for 70%-95% of the total mass, and the mass of conductive agent accounts for 70%-95% of the total mass. It is 0%-10%, and the binder mass accounts for 2%-30% of the total mass.
在本申请的部分实施例中，活性材料中，硅的重量百分含量为70％-98％，锡的重量百分含量为0.5％-20％，碳的重量百分含量为1.5-20％。In some embodiments of the present application, in the active material, the weight percentage of silicon is 70%-98%, the weight percentage of tin is 0.5%-20%, and the weight percentage of carbon is 1.5-20%. .
第二方面，本申请实施例提供了一种锂离子二次电池，包括上述负极极片。In a second aspect, embodiments of the present application provide a lithium ion secondary battery, including the above-mentioned negative electrode plate.
第三方面，本申请实施例提供了一种固态电池，包括上述负极极片。In a third aspect, embodiments of the present application provide a solid-state battery, including the above-mentioned negative electrode plate.
第四方面，本申请实施例提供了一种负极材料的制备方法，包括：将碳纳米管溶液、硅基材料、氧化锡纳米颗粒分散在有机溶剂中进行研磨、过滤、干燥后得到复合前驱体，将复合前驱体置于高温烧结炉中，在惰性气氛中升温至650-900℃，然后通入乙炔气体进行烧结，得到碳纳米管、碳包覆锡纳米线和片状硅基材料混合的负极材料。通过研磨的方式将溶剂中的碳纳米管、硅基材料以及氧化锡纳米颗粒进行混合分散，可以使三者的混合更加均匀，且可以使硅基材料全部转化成片状硅基材料。此外，在后续通入乙炔气体进行烧结的过程中，一方面可以使氧化锡还原成锡，同时，锡可以作为乙炔气体沉积的催化剂，可以得到锡纳米线的表面均匀沉积碳层的碳包覆锡纳米线，且该碳层与锡纳米线的结合更加紧密，碳层的石墨化程度高，且片状硅基材料的表面也可以沉积碳层，从而得到混合均匀的负极材料，且负极材料中的碳纳米管、碳包覆锡纳米线以及片状硅基材料之间形成三维网状结构，从而使负极材料具有很好的离子导电率和电子导电率，使负极材料的性能更佳。In the fourth aspect, embodiments of the present application provide a method for preparing an anode material, which includes: dispersing a carbon nanotube solution, a silicon-based material, and tin oxide nanoparticles in an organic solvent, grinding, filtering, and drying to obtain a composite precursor. , the composite precursor is placed in a high-temperature sintering furnace, heated to 650-900°C in an inert atmosphere, and then acetylene gas is introduced for sintering to obtain a mixture of carbon nanotubes, carbon-coated tin nanowires and sheet-like silicon-based materials. negative electrode material. Mixing and dispersing the carbon nanotubes, silicon-based materials and tin oxide nanoparticles in the solvent by grinding can make the mixing of the three more uniform, and all the silicon-based materials can be converted into flaky silicon-based materials. In addition, in the subsequent sintering process by introducing acetylene gas, on the one hand, tin oxide can be reduced to tin, and at the same time, tin can be used as a catalyst for acetylene gas deposition, and a carbon coating with a uniform carbon layer deposited on the surface of the tin nanowires can be obtained Tin nanowires, and the carbon layer is more closely combined with the tin nanowires, the carbon layer has a high degree of graphitization, and the carbon layer can also be deposited on the surface of the flaky silicon-based material, thereby obtaining a uniformly mixed negative electrode material, and the negative electrode material A three-dimensional network structure is formed between the carbon nanotubes, carbon-coated tin nanowires and sheet-like silicon-based materials, so that the negative electrode material has good ion conductivity and electronic conductivity, and the performance of the negative electrode material is better.
第五方面，本申请提供一种负极极片的制备方法，包括将片状硅基材料、导电剂、粘结剂和溶剂混合置于搅拌罐中，然后搅拌罐中的搅拌器以200-3000rad/min的速度不断搅拌，且搅拌罐本身以200-3000rad/min的速度不断转动，以得到负极活性浆料。然后将负极活性浆料涂覆在负极集流体的表面、干燥、辊压后得到负极极片。In a fifth aspect, this application provides a method for preparing a negative electrode sheet, which includes mixing sheet silicon-based materials, conductive agents, binders and solvents in a stirring tank, and then using a stirrer in the stirring tank at 200-3000rad. /min, and the mixing tank itself is continuously rotated at a speed of 200-3000rad/min to obtain the negative active slurry. Then, the negative electrode active slurry is coated on the surface of the negative electrode current collector, dried, and rolled to obtain a negative electrode piece.
通过同时控制搅拌罐中的搅拌器和搅拌罐本身的转动，可以使至少60％的所述片状硅基材料与所述负极集流体的表面的夹角≤20°。片状硅基材料倾向于与负极集流体平行，且沿负极极片的厚度方向，片状硅基材料倾向于平行排列并形成堆叠结构，可以使结构更加稳定；在进行充放电过程中，片状硅基材料沿着厚度方向发生体积变化和滑动，可以填充负极极片内部的空隙，使极片具有良好的电接触和完整性，电池的性能更佳。By simultaneously controlling the rotation of the stirrer in the stirring tank and the stirring tank itself, the angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector can be ≤20°. The sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets The volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
为了更清楚地说明本申请实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.
图1为本申请实施例1提供的负极极片(原始极片)的扫描电镜(SEM)图；Figure 1 is a scanning electron microscope (SEM) image of the negative electrode piece (original electrode piece) provided in Example 1 of the present application;
图2为本申请实施例1提供的负极极片(第五周嵌锂态)的扫描电镜(SEM)图；Figure 2 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth cycle of lithium insertion state) provided in Example 1 of the present application;
图3为对比例1提供的负极极片(原始极片)的扫描电镜(SEM)图；Figure 3 is a scanning electron microscope (SEM) image of the negative electrode piece (original electrode piece) provided in Comparative Example 1;
图4为对比例1提供的负极极片(第五周嵌锂态)的扫描电镜(SEM)图；Figure 4 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth week of lithium insertion state) provided in Comparative Example 1;
图5为本申请实施例1提供的活性材料的X射线衍射(XRD)图；Figure 5 is an X-ray diffraction (XRD) pattern of the active material provided in Example 1 of the present application;
图6为本申请实施例1提供的负极极片在辊压前的X射线衍射(XRD)图；Figure 6 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the present application before rolling;
图7为本申请实施例1提供的负极极片在辊压后的X射线衍射(XRD)图；
Figure 7 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the present application after rolling;
图8为本申请实施例1提供的半电池的充放电曲线图；Figure 8 is a charge-discharge curve of the half-cell provided in Embodiment 1 of the present application;
图9为本申请实施例1提供的负极活性材料的扫描电镜(SEM)图；Figure 9 is a scanning electron microscope (SEM) image of the negative active material provided in Example 1 of the present application;
图10为本申请实施例9提供的负极活性材料的扫描电镜(SEM)图；Figure 10 is a scanning electron microscope (SEM) image of the negative active material provided in Example 9 of the present application;
图11为本申请实施例1提供的电池循环5周后的负极活性材料的扫描电镜(SEM)图；Figure 11 is a scanning electron microscope (SEM) image of the negative active material of the battery provided in Example 1 of the present application after 5 weeks of cycling;
图12为对比例3提供的负极活性材料的扫描电镜(SEM)图；Figure 12 is a scanning electron microscope (SEM) image of the negative active material provided in Comparative Example 3;
图13为本申请实施例1提供的碳包覆锡纳米线的透射电镜(TEM)图；Figure 13 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 1 of the present application;
图14为本申请实施例10提供的碳包覆锡纳米线的透射电镜(TEM)图；Figure 14 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 10 of the present application;
图15为本申请实施例1以及实施例9提供的电池的阻抗图；Figure 15 is an impedance diagram of the battery provided in Example 1 and Example 9 of the present application;
图16为本申请实施例1提供的电池在2C条件下的循环性能图。Figure 16 is a cycle performance diagram of the battery provided in Example 1 of the present application under 2C conditions.
为使本申请实施例的目的、技术方案和优点更加清楚，下面对本申请的技术方案进行清楚、完整地描述。In order to make the purpose, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the present application are described clearly and completely below.
本申请实施例提供了一种负极极片，包括负极集流体以及设置于负极集流体表面的负极活性材料层。负极活性材料层包括活性材料，导电剂和粘结剂。通过其形成负极活性材料层，可以使负极极片具有很好的导电性以及电池性能，并且能够使负极活性材料层很好地结合在负极集流体上。Embodiments of the present application provide a negative electrode sheet, which includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector. The negative active material layer includes active material, conductive agent and binder. By forming the negative active material layer, the negative electrode piece can have good conductivity and battery performance, and the negative active material layer can be well combined with the negative current collector.
可选地，以活性材料、导电剂和粘结剂三者质量和为总质量，活性材料质量占总质量的百分数为70％-95％，导电剂质量占总质量的百分数为0％-10％，粘结剂质量占总质量的百分数为5％-30％。可以使负极活性材料层的致密性、比容量和首充均较佳。Optionally, the sum of the masses of the active material, conductive agent and binder is the total mass, the mass of the active material accounts for 70%-95% of the total mass, and the mass of the conductive agent accounts for 0%-10% of the total mass. %, the binder mass accounts for 5%-30% of the total mass. The density, specific capacity and first charge of the negative active material layer can be improved.
作为示例性地，活性材料质量占总质量的百分数为70％、75％、80％、85％、90％或95％；导电剂质量占总质量的百分数为0％、2％、4％、6％、8％或10％；粘结剂质量占总质量的百分数为2％、10％、15％、20％、25％或30％。As an example, the mass percentage of the active material to the total mass is 70%, 75%, 80%, 85%, 90% or 95%; the mass percentage of the conductive agent to the total mass is 0%, 2%, 4%, 6%, 8% or 10%; the percentage of binder mass to the total mass is 2%, 10%, 15%, 20%, 25% or 30%.
其中，导电剂可以是导电炭黑、导电石墨、导电碳纤维、碳纳米管和石墨烯中一种或几种组合；粘结剂可以是羧甲基纤维素、丁苯橡胶、聚丙烯酸、聚丙烯酸钠、聚丙烯酸锂，海藻酸钠、聚偏二氟乙烯中一种或几种组合。Among them, the conductive agent can be one or more combinations of conductive carbon black, conductive graphite, conductive carbon fiber, carbon nanotubes and graphene; the binder can be carboxymethylcellulose, styrene-butadiene rubber, polyacrylic acid, polyacrylic acid One or a combination of sodium, lithium polyacrylate, sodium alginate, and polyvinylidene fluoride.
本申请中，活性材料包括片状硅基材料。片状硅基材料是指：材料中含有硅，并且能够实现脱嵌锂的硅基材料；硅基材料为片状，且片状材料的厚度为纳米级。In this application, the active material includes sheet-shaped silicon-based material. Sheet-like silicon-based materials refer to silicon-based materials that contain silicon and can deintercalate lithium; the silicon-based materials are in the form of sheets, and the thickness of the sheet-like materials is at the nanometer level.
可选地，片状硅基材料为硅纳米片(硅单质)、硅亚微米片(硅单质)、硅合金纳米片(硅合金)、硅合金亚微米片(硅合金)、硅氧纳米片(硅氧材料SOx，0＜x＜2)和硅氧亚微米片(硅氧材料SOx，0＜x＜2)及其表面改性包覆后的材料的一种或多种。Optionally, the flaky silicon-based material is silicon nanosheets (silicon elemental substance), silicon submicron flakes (silicon elemental substance), silicon alloy nanosheets (silicon alloy), silicon alloy submicron flakes (silicon alloy), silicon oxygen nanosheets (Silicon-oxygen material SO x , 0<x<2) and silicon-oxygen submicron sheets (silica-oxygen material SO x , 0<x<2) and one or more of their surface-modified and coated materials.
其中，硅纳米片是指：硅单质为片状，该硅片的厚度为纳米级。可选地，硅纳米片的厚度为1-100nm，平面尺寸为20-5000nm。其中，硅纳米片的厚度是指：硅纳米片的两个表面之间的最大距离；硅纳米片的平面尺寸是指：该片状结构的硅纳米片在水平面上的投影的轮廓线中，距离最远的两个点之间的距离。例如：硅纳米片的厚度为1nm、5nm、10nm、20nm、40nm、60nm、80nm或100nm；硅纳米片的平面尺寸为20nm、50nm、100nm、200nm、400nm、600nm、800nm、1000nm、1200nm、1400nm、1600nm、1800nm或2000nm。Among them, silicon nanosheets refer to: silicon element is in the form of a sheet, and the thickness of the silicon sheet is at the nanometer level. Optionally, the silicon nanosheet has a thickness of 1-100nm and a planar size of 20-5000nm. Among them, the thickness of the silicon nanosheet refers to: the maximum distance between the two surfaces of the silicon nanosheet; the plane size of the silicon nanosheet refers to: in the outline of the projection of the sheet-like structure of the silicon nanosheet on the horizontal plane, The distance between the two furthest points. For example: the thickness of silicon nanosheets is 1nm, 5nm, 10nm, 20nm, 40nm, 60nm, 80nm or 100nm; the plane size of silicon nanosheets is 20nm, 50nm, 100nm, 200nm, 400nm, 600nm, 800nm, 1000nm, 1200nm, 1400nm , 1600nm, 1800nm or 2000nm.
可选地，硅纳米片的表面还包覆有厚度为纳米级的碳层。一方面，碳层较薄，能够保持活性材料较高的比容量；另一方面，碳层的包覆，可以在一定程度上避免片状硅基材料与电解液直接接触，活性材
料的循环稳定性进一步提高。可选地，片状硅基材料上的碳包覆层的厚度为2-10nm。Optionally, the surface of the silicon nanosheet is also coated with a carbon layer with a thickness of nanometer level. On the one hand, the thin carbon layer can maintain a high specific capacity of the active material; on the other hand, the coating of the carbon layer can avoid direct contact between the flaky silicon-based material and the electrolyte to a certain extent, and the active material The cycle stability of the material is further improved. Optionally, the thickness of the carbon coating layer on the sheet-shaped silicon-based material is 2-10 nm.
本申请中，以负极集流体的表面为基准，至少60％的片状硅基材料与负极集流体的表面的夹角≤20°；也就是说，以负极集流体的平面方向为基准，至少60％的片状硅基材料与负极集流体的之间的倾斜角≤20°。In this application, based on the surface of the negative electrode current collector, the angle between at least 60% of the sheet-shaped silicon-based materials and the surface of the negative electrode current collector is ≤20°; that is, based on the plane direction of the negative electrode current collector, at least The tilt angle between 60% of the sheet silicon-based material and the negative electrode current collector is ≤20°.
片状硅基材料倾向于与负极集流体平行，且沿负极极片的厚度方向，片状硅基材料倾向于平行排列并形成堆叠结构，可以使结构更加稳定；在进行充放电过程中，片状硅基材料沿着厚度方向发生体积变化和滑动，可以填充负极极片内部的空隙，使极片具有良好的电接触和完整性，电池的性能更佳。The sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets The volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
可选地，沿负极极片的厚度方向，相邻两片片状硅基材料之间的夹角≤10°。可以使片状硅基材料在负极集流体上分布的一致性更好，从而可以使更多的片状硅基材料以堆叠的形式存在，以便提高电池的性能。Optionally, along the thickness direction of the negative electrode plate, the angle between two adjacent pieces of silicon-based material is ≤10°. The distribution of sheet-like silicon-based materials on the negative electrode current collector can be made more consistent, so that more sheet-like silicon-based materials can exist in a stacked form to improve battery performance.
进一步地，至少90％的片状硅基材料与负极集流体的表面的夹角≤20°；且沿负极极片的厚度方向，相邻两片片状硅基材料之间的夹角≤5°。更多的片状硅基材料与负极集流体基本平行并形成堆叠结构，可以使电池的性能更佳。Further, the angle between at least 90% of the sheet-like silicon-based materials and the surface of the negative electrode current collector is ≤ 20°; and along the thickness direction of the negative electrode plate, the angle between two adjacent pieces of sheet-like silicon-based materials is ≤ 5 °. More sheet-like silicon-based materials are basically parallel to the negative electrode current collector and form a stacked structure, which can make the battery perform better.
进一步地，全部片状硅基材料与负极集流体的表面的夹角≤20°。所有的片状硅基材料基本均倾向于与负极集流体平行，从而使电池的性能更好。Further, the angle between all the sheet-shaped silicon-based materials and the surface of the negative electrode current collector is ≤20°. All flaky silicon-based materials basically tend to be parallel to the negative current collector, resulting in better battery performance.
本申请中，活性材料还包括碳包覆锡纳米线作为协同活性材料。碳包覆锡纳米线是指：锡纳米线的表面包覆有碳层，形成的碳包覆锡纳米线依然是线状结构，且其尺寸也是纳米级。锡材料本身具有很好的导电性和离子导电能力，与包覆碳层配合以后，具有快速充放电能力；且碳层的包覆可以使其在充放电过程中的结构保持完整，并实现良好的电接触。可选地，碳包覆锡纳米线中碳包覆层的厚度为纳米级。可选地，碳包覆锡纳米线上的碳包覆层的厚度为2-10nm。In this application, the active material also includes carbon-coated tin nanowires as synergistic active materials. Carbon-coated tin nanowires refer to: the surface of the tin nanowires is coated with a carbon layer, and the carbon-coated tin nanowires formed are still linear structures, and their sizes are also nanoscale. The tin material itself has good electrical conductivity and ionic conductivity. When combined with the coating carbon layer, it has rapid charge and discharge capabilities; and the coating of the carbon layer can keep its structure intact during the charge and discharge process and achieve good performance. electrical contact. Optionally, the thickness of the carbon coating layer in the carbon-coated tin nanowire is nanoscale. Optionally, the thickness of the carbon coating layer on the carbon-coated tin nanowire is 2-10 nm.
碳包覆锡纳米线的直径在100nm以下，长径比为(5-1000):1。碳包覆锡纳米线的不同部位的直径可以相同，也可以不同，直径在100nm以下且长径比为(5-1000):1，可以使其柔韧性更好，片状硅基材料混合以后，能够与片状硅基材料形成三维网络结构，可以在一定程度上避免片状硅基材料的体积膨胀。可选地，碳包覆锡纳米线的长径比为5:1、10:1、20:1、40:1、80:1、160:1、320:1、480:1、600:1或1000:1。The diameter of the carbon-coated tin nanowire is below 100nm, and the aspect ratio is (5-1000):1. The diameters of different parts of the carbon-coated tin nanowires can be the same or different. The diameter is below 100nm and the aspect ratio is (5-1000):1, which can make it more flexible. After mixing the flaky silicon-based materials , can form a three-dimensional network structure with flaky silicon-based materials, which can avoid the volume expansion of flaky silicon-based materials to a certain extent. Optionally, the aspect ratio of the carbon-coated tin nanowire is 5:1, 10:1, 20:1, 40:1, 80:1, 160:1, 320:1, 480:1, 600:1 Or 1000:1.
可选地，碳包覆锡纳米线是通过原位还原氧化锡纳米颗粒和碳沉积形成的。在高温通入还原气体(例如：乙炔气体)的时候，一边还原氧化锡为锡，一边利用锡作为催化剂，可以得到锡纳米线的表面均匀沉积碳层的碳包覆锡纳米线，且锡纳米线的表面均匀沉积碳层，且该碳层与锡纳米线的结合更加紧密，碳层的石墨化程度高，有利于提高负极材料的性能。Alternatively, carbon-coated tin nanowires are formed by in-situ reduction of tin oxide nanoparticles and carbon deposition. When reducing gas (for example, acetylene gas) is introduced at high temperature, tin oxide is reduced to tin while using tin as a catalyst to obtain carbon-coated tin nanowires with a carbon layer evenly deposited on the surface of the tin nanowires, and the tin nanowires are The carbon layer is uniformly deposited on the surface of the wire, and the carbon layer is more closely combined with the tin nanowire. The carbon layer has a high degree of graphitization, which is beneficial to improving the performance of the negative electrode material.
可选地，碳包覆锡纳米线中碳包覆层的石墨化度γ满足0.3≦γ≦1，其中γ＝(0.344-d002)/(0.344-0.3354)，d002为碳包覆层在002晶面的纳米层间距。在高温通入还原气体(例如：乙炔气体)的时候，一边还原氧化锡为锡，一边利用锡作为催化剂，可以得到锡纳米线的表面均匀沉积碳层的碳包覆锡纳米线，且锡纳米线的表面均匀沉积碳层，且该碳层与锡纳米线的结合更加紧密，碳层的石墨化程度高，可以使碳包覆锡纳米线中碳层的石墨化度在0.3-1之间，其石墨化度较高，有利于提高负极材料的性能。Optionally, the graphitization degree γ of the carbon coating layer in the carbon-coated tin nanowire satisfies 0.3≦γ≦1, where γ=(0.344-d 002 )/(0.344-0.3354), d 002 is the carbon coating layer Nanolayer spacing in the 002 crystal plane. When reducing gas (for example, acetylene gas) is introduced at high temperature, tin oxide is reduced to tin while using tin as a catalyst to obtain carbon-coated tin nanowires with a carbon layer evenly deposited on the surface of the tin nanowires, and the tin nanowires are The carbon layer is uniformly deposited on the surface of the wire, and the carbon layer is more closely combined with the tin nanowire. The graphitization degree of the carbon layer is high, which can make the graphitization degree of the carbon layer in the carbon-coated tin nanowire be between 0.3-1. , its graphitization degree is high, which is beneficial to improving the performance of negative electrode materials.
可选地，碳包覆锡纳米线中碳包覆层的石墨化度γ为0.3-0.6或0.6-1；作为示例性地，碳包覆锡纳米线中碳包覆层的石墨化度γ为0.3、0.4、0.5、0.6、0.7、0.8、0.9或1。Optionally, the graphitization degree γ of the carbon coating layer in the carbon-coated tin nanowire is 0.3-0.6 or 0.6-1; as an example, the graphitization degree γ of the carbon coating layer in the carbon-coated tin nanowire is is 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.
本申请中，活性材料还包括碳纳米管作为协同活性材料。碳纳米管是指：碳材料为管状，碳管的外径为纳米级。碳纳米管的直径在20nm以下，长径比为(10-1000):1。碳纳米管的不同部位的直径可以相
同，也可以不同，直径在20nm以下且长径比为(10-1000):1。由于碳包覆锡纳米线和碳纳米管均具有一定的弹性和柔韧性，与片状硅基材料进行混合以后，可以形成更好的三维导电网络，可以缓解负极极片脱嵌锂的体积效应，使电池的比容量较大、循环稳定性较高；同时，负极极片具有很好的离子导电率和电子导电率，导电能力更好。In this application, the active material also includes carbon nanotubes as synergistic active materials. Carbon nanotubes refer to carbon materials that are in the form of tubes, and the outer diameter of the carbon tubes is nanoscale. The diameter of carbon nanotubes is below 20nm, and the aspect ratio is (10-1000):1. The diameters of different parts of carbon nanotubes can be similar The same or different, the diameter is below 20nm and the aspect ratio is (10-1000):1. Since both carbon-coated tin nanowires and carbon nanotubes have a certain degree of elasticity and flexibility, when mixed with sheet-like silicon-based materials, a better three-dimensional conductive network can be formed, which can alleviate the volume effect of lithium deintercalation in the negative electrode. , making the battery have a larger specific capacity and higher cycle stability; at the same time, the negative electrode plate has good ionic conductivity and electronic conductivity, and better conductivity.
可选地，碳纳米管至少包括单壁碳纳米管。可以使负极极片的性能更佳。可选地，碳纳米管还可以是单壁碳纳米管和多壁碳纳米管的混合物。Optionally, the carbon nanotubes include at least single-walled carbon nanotubes. It can make the performance of the negative electrode piece better. Alternatively, the carbon nanotubes may also be a mixture of single-walled carbon nanotubes and multi-walled carbon nanotubes.
本申请的活性材料中，硅的重量百分含量为70％-98％，锡的重量百分含量为0.5％-20％，碳的重量百分含量为1.5-20％。其中，硅、锡和碳的重量百分含量是指元素含量，例如：碳的重量百分含量是指：碳包覆锡纳米线的碳和碳纳米管的碳的重量百分含量之和；硅的重量百分含量是指：片状硅基材料中硅的重量百分含量；锡的重量百分含量是指：碳包覆锡纳米线中锡的重量百分含量。In the active material of the present application, the weight percentage of silicon is 70%-98%, the weight percentage of tin is 0.5%-20%, and the weight percentage of carbon is 1.5-20%. Among them, the weight percentage of silicon, tin and carbon refers to the element content. For example: the weight percentage of carbon refers to the sum of the weight percentage of carbon in carbon-coated tin nanowires and carbon in carbon nanotubes; The weight percentage of silicon refers to the weight percentage of silicon in the sheet-shaped silicon-based material; the weight percentage of tin refers to the weight percentage of tin in the carbon-coated tin nanowires.
例如：硅的重量百分含量为70％、74％、78％、82％、86％、90％、94％或98％；锡的重量百分含量为0.5％、1％、2％、4％、8％、12％、16％或20％；碳的重量百分含量为1.5％、3％、5％、8％、10％、12％、14％、16％、18％或20％。For example: the weight percentage of silicon is 70%, 74%, 78%, 82%, 86%, 90%, 94% or 98%; the weight percentage of tin is 0.5%, 1%, 2%, 4 %, 8%, 12%, 16% or 20%; carbon weight percentage is 1.5%, 3%, 5%, 8%, 10%, 12%, 14%, 16%, 18% or 20% .
本申请提供的负极极片的单面面密度为1-40mg/cm2。其可以用来制备二次电池，例如：锂离子电池或全固态电池等，可以使电池的比容量为1000-3000mAh/g，首次充放电库伦效率≥80％，以提高电池的性能。The single-surface density of the negative electrode piece provided by this application is 1-40 mg/cm 2 . It can be used to prepare secondary batteries, such as lithium-ion batteries or all-solid-state batteries. It can make the battery have a specific capacity of 1000-3000mAh/g and a first charge and discharge Coulombic efficiency of ≥80% to improve battery performance.
上面介绍了负极极片的结构以后，下面对负极极片的制备方法进行介绍。After introducing the structure of the negative electrode piece above, the preparation method of the negative electrode piece will be introduced below.
本申请中，可以是直接将负极活性材料(包括片状硅基材料)、导电剂、粘结剂和溶剂混合置于搅拌罐中，然后搅拌罐中的搅拌器以200-3000rad/min的速度不断搅拌，且搅拌罐本身以200-3000rad/min的速度不断转动，以得到负极活性浆料。然后将负极活性浆料涂覆在负极集流体的表面、干燥、辊压后得到负极极片。In this application, the negative active material (including flake silicon-based material), conductive agent, binder and solvent can be directly mixed and placed in a stirring tank, and then the stirrer in the stirring tank operates at a speed of 200-3000rad/min. Stir continuously, and the mixing tank itself continuously rotates at a speed of 200-3000rad/min to obtain the negative electrode active slurry. Then, the negative electrode active slurry is coated on the surface of the negative electrode current collector, dried, and rolled to obtain a negative electrode piece.
上述技术方案中，通过同时控制搅拌罐中的搅拌器和搅拌罐本身的转动，可以使至少60％的所述片状硅基材料与所述负极集流体的表面的夹角≤20°。片状硅基材料倾向于与负极集流体平行，且沿负极极片的厚度方向，片状硅基材料倾向于平行排列并形成堆叠结构，可以使结构更加稳定；在进行充放电过程中，片状硅基材料沿着厚度方向发生体积变化和滑动，可以填充负极极片内部的空隙，使极片具有良好的电接触和完整性，电池的性能更佳。In the above technical solution, by simultaneously controlling the rotation of the stirrer in the stirring tank and the stirring tank itself, the angle between at least 60% of the sheet-shaped silicon-based material and the surface of the negative electrode current collector can be ≤20°. The sheet-shaped silicon-based materials tend to be parallel to the negative electrode current collector, and along the thickness direction of the negative electrode sheet, the sheet-shaped silicon-based materials tend to be arranged in parallel and form a stacked structure, which can make the structure more stable; during the charging and discharging process, the sheets The volume change and sliding of the silicon-like material along the thickness direction can fill the gaps inside the negative electrode piece, so that the electrode piece has good electrical contact and integrity, and the battery performance is better.
可选地，搅拌器的转速可以是200-1000rad/min或1000-3000rad/min，搅拌罐本身的转速可以是200-1000rad/min或1000-3000rad/min。作为示例性地，搅拌器和搅拌罐的转速可以独立地选自200rad/min、500rad/min、1000rad/min、1500rad/min、2000rad/min、2500rad/min或3000rad/min。Alternatively, the rotation speed of the agitator can be 200-1000rad/min or 1000-3000rad/min, and the rotation speed of the mixing tank itself can be 200-1000rad/min or 1000-3000rad/min. As an example, the rotation speed of the stirrer and the stirring tank can be independently selected from 200rad/min, 500rad/min, 1000rad/min, 1500rad/min, 2000rad/min, 2500rad/min or 3000rad/min.
进一步地，负极活性材料的制备方法可以是：将碳纳米管溶液、硅基材料、氧化锡纳米颗粒分散在有机溶剂中进行研磨(例如：球磨、砂磨等)、过滤、干燥后得到复合前驱体，将复合前驱体置于高温烧结炉中，在惰性气氛中升温至650-900℃，然后通入乙炔气体进行烧结，得到碳纳米管、碳包覆锡纳米线和片状硅基材料混合的负极材料。Further, the preparation method of the negative active material can be: dispersing the carbon nanotube solution, silicon-based material, and tin oxide nanoparticles in an organic solvent, grinding (such as ball milling, sand milling, etc.), filtering, and drying to obtain a composite precursor. The composite precursor is placed in a high-temperature sintering furnace, heated to 650-900°C in an inert atmosphere, and then acetylene gas is introduced for sintering to obtain a mixture of carbon nanotubes, carbon-coated tin nanowires and sheet-like silicon-based materials. negative electrode material.
通过研磨的方式将溶剂中的碳纳米管、硅基材料以及氧化锡纳米颗粒进行混合分散，可以使三者的混合更加均匀，且可以使硅基材料全部转化成片状硅基材料。此外，在后续通入乙炔气体进行烧结的过程中，一方面可以使氧化锡还原成锡，同时，锡可以作为乙炔气体沉积的催化剂，可以得到锡纳米线的表面均匀沉积碳层的碳包覆锡纳米线，且该碳层与锡纳米线的结合更加紧密，碳层的石墨化程度高，且片状硅基材料的表面也可以沉积碳层，从而得到混合均匀的负极材料，且负极材料中的碳纳米管、碳包
覆锡纳米线以及碳包覆片状硅基材料之间形成三维网状结构，从而使负极材料具有很好的离子导电率和电子导电率，使负极材料的性能更佳。Mixing and dispersing the carbon nanotubes, silicon-based materials and tin oxide nanoparticles in the solvent by grinding can make the mixing of the three more uniform, and all the silicon-based materials can be converted into flaky silicon-based materials. In addition, in the subsequent sintering process by introducing acetylene gas, on the one hand, tin oxide can be reduced to tin, and at the same time, tin can be used as a catalyst for acetylene gas deposition, and a carbon coating with a uniform carbon layer deposited on the surface of the tin nanowires can be obtained Tin nanowires, and the carbon layer is more closely combined with the tin nanowires, the carbon layer has a high degree of graphitization, and the carbon layer can also be deposited on the surface of the flaky silicon-based material, thereby obtaining a uniformly mixed negative electrode material, and the negative electrode material Carbon nanotubes, carbon packets in A three-dimensional network structure is formed between the tin-coated nanowires and the carbon-coated sheet-like silicon-based material, so that the negative electrode material has good ion conductivity and electronic conductivity, and the performance of the negative electrode material is better.
负极活性材料的制备方法还可以是：氧化锡纳米颗粒放入高温烧结炉中，在惰性气氛中升温至650-900℃，并通入乙炔气体进行烧结，烧结完后即可得到碳包覆锡纳米线。将碳纳米管溶液、片状硅基材料、碳包覆锡纳米线分散在有机溶剂中、过滤、干燥后得到碳纳米管、碳包覆锡纳米线和片状硅基材料混合的负极材料。The preparation method of the negative active material can also be: put the tin oxide nanoparticles into a high-temperature sintering furnace, raise the temperature to 650-900°C in an inert atmosphere, and introduce acetylene gas for sintering. After sintering, carbon-coated tin can be obtained Nanowires. The carbon nanotube solution, flaky silicon-based material, and carbon-coated tin nanowires are dispersed in an organic solvent, filtered, and dried to obtain a negative electrode material mixed with carbon nanotubes, carbon-coated tin nanowires, and flaky silicon-based materials.
在通入乙炔气体进行烧结的过程中，一方面可以使氧化锡还原成锡，同时，锡可以作为乙炔气体沉积的催化剂，可以使锡纳米线的表面均匀沉积碳层，且该碳层与锡纳米线的结合更加紧密，碳层的石墨化程度高的碳包覆锡纳米线。将碳纳米管、碳包覆锡纳米线以及片状硅基材料混合在溶剂中，得到混合均匀的负极材料；同时，三者在一定程度上形成了三维网状结构，从而使负极材料具有较好的离子导电率和电子导电率，使负极材料的性能更佳。In the process of sintering by introducing acetylene gas, on the one hand, tin oxide can be reduced to tin, and at the same time, tin can be used as a catalyst for the deposition of acetylene gas, which can uniformly deposit a carbon layer on the surface of the tin nanowires, and the carbon layer and the tin The nanowires are more tightly bonded, and the carbon layer has a high degree of graphitization in carbon-coated tin nanowires. Carbon nanotubes, carbon-coated tin nanowires, and flaky silicon-based materials are mixed in a solvent to obtain a uniformly mixed anode material; at the same time, the three form a three-dimensional network structure to a certain extent, making the anode material have a higher Good ionic conductivity and electronic conductivity make the negative electrode material perform better.
可选地，烧结的温度可以是650-750℃或750-900℃；作为示例性地，烧结的温度可以是650℃、700℃、750℃、800℃、850℃或900℃。Alternatively, the sintering temperature may be 650-750°C or 750-900°C; as an example, the sintering temperature may be 650°C, 700°C, 750°C, 800°C, 850°C or 900°C.
为使本申请实施例的目的、技术方案和优点更加清楚，下面将对本申请实施例中的技术方案进行清楚、完整地描述。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者，均为可以通过市售购买获得的常规产品。In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.
实施例1Example 1
(1)碳纳米管溶液的制备：(1) Preparation of carbon nanotube solution:
将碳纳米管分散在乙醇溶剂中得到碳纳米管溶液，其中，碳纳米管与乙醇的质量比为1:100。The carbon nanotubes are dispersed in an ethanol solvent to obtain a carbon nanotube solution, where the mass ratio of the carbon nanotubes to ethanol is 1:100.
(2)活性材料的制备：(2) Preparation of active materials:
向碳纳米管溶液中加入太阳能硅片切割废料、氧化锡、聚乙烯吡咯烷酮(PVP)在均质机中均质分散，将均质分散后的悬浊液在砂磨机中砂磨5h，然后过滤、洗涤、烘干后获得均匀分散的复合前驱体。最后将前驱体材料放入高温烧结炉中在氮气气氛下从室温升到700℃烧结，并通入乙炔气体进行碳包覆，烧结完后即可得到活性材料。Add solar silicon wafer cutting waste, tin oxide, and polyvinylpyrrolidone (PVP) to the carbon nanotube solution and homogeneously disperse it in a homogenizer. Sand the homogeneously dispersed suspension in a sand mill for 5 hours, and then After filtering, washing and drying, a uniformly dispersed composite precursor is obtained. Finally, the precursor material is put into a high-temperature sintering furnace and sintered from room temperature to 700°C in a nitrogen atmosphere, and acetylene gas is introduced for carbon coating. After sintering, the active material can be obtained.
该活性材料包括硅纳米片、碳包覆锡纳米线和碳纳米管，且硅纳米片表面包覆有碳层。硅纳米片的厚度为10-80nm，平面尺寸为200-800nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的86.6wt％；锡占活性材料的4.6wt％；碳占活性材料的5.2wt％；其他物质占活性材料的3.1wt％。The active material includes silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon nanosheets is coated with a carbon layer. The thickness of silicon nanosheets is 10-80nm, and the planar size is 200-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 86.6wt% of the active material; tin accounts for 4.6wt% of the active material; carbon accounts for 5.2wt% of the active material; and other substances account for 3.1wt% of the active material.
(3)负极极片的制备：(3) Preparation of negative electrode plate:
将上述制备得到的负极活性材料与导电剂(SP)、羧甲基纤维素钠(CMC)、丁苯橡胶(SBR)按照质量比为80：5：5：10的比例添加在装放有水的搅拌罐中，搅拌罐中的搅拌器以500rad/min的速度不断搅拌，且搅拌罐本身以500rad/min的速度不断转动，以得到负极活性材料浆料。将负极活性材料浆料用刮刀涂覆于铜箔表面，再经烘干处理得到负极极片。将负极极片进行辊压处理，将辊压后的负极极片用打孔器制备出直径为15mm小圆片。Add the negative active material prepared above to the conductive agent (SP), sodium carboxymethylcellulose (CMC), and styrene-butadiene rubber (SBR) in a container of water in a mass ratio of 80:5:5:10. In the mixing tank, the agitator in the mixing tank continuously stirs at a speed of 500 rad/min, and the mixing tank itself continuously rotates at a speed of 500 rad/min to obtain the negative active material slurry. The negative active material slurry is coated on the surface of the copper foil with a scraper, and then dried to obtain a negative electrode piece. The negative electrode piece is rolled, and a punch is used to prepare a small round piece with a diameter of 15 mm from the rolled negative electrode piece.
(4)半电池的制备(4) Preparation of half cells
将上述的负极极片与锂片配对装配成扣式半电池，电池的装配过程在充满氩气的手套箱中进行。其中使用Celgard2300膜为隔离膜，电解液为1mol/L的LiPF6溶解于EC:DMC:FEC(体积比4.8:4.8:0.4)的溶液。
The above-mentioned negative electrode sheet and lithium sheet are paired and assembled into a button half battery. The battery assembly process is carried out in a glove box filled with argon gas. Celgard2300 membrane is used as the isolation membrane, and the electrolyte is a solution of 1 mol/L LiPF 6 dissolved in EC:DMC:FEC (volume ratio 4.8:4.8:0.4).
实施例2Example 2
实施例2与实施例1的区别在于：步骤(2)中，将太阳能硅片切割废料替换成粒径为5-10μm的氧化亚硅。The difference between Example 2 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with silicon oxide with a particle size of 5-10 μm.
该活性材料包括氧化亚硅纳米片、碳包覆锡纳米线和碳纳米管，且氧化亚硅纳米片表面包覆有碳层。氧化亚硅纳米片的厚度为50-80nm，平面尺寸为200-800nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的60.8wt％；氧占活性材料的29.3wt％，锡占活性材料的4.6wt％；碳占活性材料的4.8wt％；其他物质占活性材料的0.5wt％。The active material includes silicon oxide nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon oxide nanosheets is coated with a carbon layer. The thickness of silicon oxide nanosheets is 50-80nm, and the planar size is 200-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500): 1; the diameter of carbon nanotubes is 10-20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 60.8wt% of active materials; oxygen accounts for 29.3wt% of active materials; tin accounts for 4.6wt% of active materials; carbon accounts for 4.8wt% of active materials; other substances account for 0.5% of active materials. wt%.
实施例3Example 3
实施例3与实施例1的区别在于：步骤(2)中，将太阳能硅片切割废料替换成粒径为5-10μm的硅铁合金。The difference between Example 3 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with ferrosilicon alloy with a particle size of 5-10 μm.
该活性材料包括硅铁合金纳米片、碳包覆锡纳米线和碳纳米管，且硅铁合金纳米片表面包覆有碳层。硅铁合金纳米片的厚度为20-60nm，平面尺寸为100-500nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的76.3wt％；铁占活性材料的12.1wt％，锡占活性材料的3.5wt％；碳占活性材料的7.6wt％；其他物质占活性材料的0.5wt％。The active material includes ferrosilicon alloy nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the ferrosilicon alloy nanosheets is coated with a carbon layer. The thickness of ferrosilicon alloy nanosheets is 20-60nm, and the planar size is 100-500nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10 -20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 76.3wt% of active materials; iron accounts for 12.1wt% of active materials, tin accounts for 3.5wt% of active materials; carbon accounts for 7.6wt% of active materials; other substances account for 0.5% of active materials. wt%.
实施例4Example 4
实施例4与实施例1的区别在于：步骤(1)中，将太阳能硅片切割废料替换成厚度为10-50nm；平面尺寸为100-600nm的硅纳米片，不需要在砂磨机中砂磨。The difference between Embodiment 4 and Embodiment 1 is that in step (1), the solar silicon wafer cutting waste is replaced with silicon nanosheets with a thickness of 10-50nm and a planar size of 100-600nm, and does not need to be sanded in a sand mill. grind.
该活性材料包括硅纳米片、碳包覆锡纳米线和碳纳米管。硅纳米片的厚度为10-50nm，平面尺寸为100-600nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的87.6wt％；锡占活性材料的4.3wt％；碳占活性材料的7.8wt％；其他物质占活性材料的0.3wt％。The active materials include silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes. The thickness of silicon nanosheets is 10-50nm, and the planar size is 100-600nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 87.6wt% of the active material; tin accounts for 4.3wt% of the active material; carbon accounts for 7.8wt% of the active material; and other substances account for 0.3wt% of the active material.
实施例5Example 5
实施例5与实施例1的区别在于：步骤(2)中，将太阳能硅片切割废料替换成厚度为50-100nm；平面尺寸为100-800nm的氧化亚硅纳米片，不需要在砂磨机中砂磨。The difference between Embodiment 5 and Embodiment 1 is that in step (2), the solar silicon wafer cutting waste is replaced with silicon oxide nanosheets with a thickness of 50-100nm and a planar size of 100-800nm. There is no need to use a sand mill. Medium sanding.
该活性材料包括氧化亚硅纳米片、碳包覆锡纳米线和碳纳米管。氧化亚硅纳米片的厚度为50-100nm，平面尺寸为100-800nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的61.2wt％；氧占活性材料的28.5wt％锡占活性材料的3.6wt％；碳占活性材料的4.2wt％；其他物质占活性材料的3.1wt％。The active materials include silicon oxide nanosheets, carbon-coated tin nanowires and carbon nanotubes. The thickness of silicon oxide nanosheets is 50-100nm, and the planar size is 100-800nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10-20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 61.2wt% of the active material; oxygen accounts for 28.5wt% of the active material; tin accounts for 3.6wt% of the active material; carbon accounts for 4.2wt% of the active material; other substances account for 3.1wt of the active material. %.
实施例6Example 6
实施例5与实施例1的区别在于：步骤(2)中，将太阳能硅片切割废料替换成厚度为50-80nm；平面尺寸为200-600nm的硅铁合金纳米片，不需要在砂磨机中砂磨。The difference between Embodiment 5 and Embodiment 1 is that: in step (2), the solar silicon wafer cutting waste is replaced with ferrosilicon alloy nanosheets with a thickness of 50-80nm and a planar size of 200-600nm, and does not need to be used in a sand mill. Sanding.
该活性材料包括硅铁合金纳米片、碳包覆锡纳米线和碳纳米管。硅铁合金纳米片的厚度为50-80nm，平面尺寸为200-600nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的74.6wt％；铁占活性材料的11.5wt％，锡占活性材料的3.2wt％；碳占活性材料的7.6wt％；其他物质占活性材料的2.1wt％。The active materials include ferrosilicon alloy nanosheets, carbon-coated tin nanowires and carbon nanotubes. The thickness of ferrosilicon alloy nanosheets is 50-80nm, and the planar size is 200-600nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10 -20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 74.6wt% of active materials; iron accounts for 11.5wt% of active materials, tin accounts for 3.2wt% of active materials; carbon accounts for 7.6wt% of active materials; other substances account for 2.1% of active materials. wt%.
实施例7Example 7
实施例7与实施例1的区别在于：步骤(2)中，将太阳能硅片切割废料替换成粒径为5-10μm的单晶硅。The difference between Example 7 and Example 1 is that in step (2), the solar silicon wafer cutting waste is replaced with single crystal silicon with a particle size of 5-10 μm.
该活性材料包括硅纳米片、碳包覆锡纳米线和碳纳米管，且硅纳米片表面包覆有碳层。硅纳米片的厚度为50-100nm，平面尺寸为200-1000nm；碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的84.6wt％；锡占活性材料的5.1wt％；碳占活性材料的6.9wt％；其他物质占活性材料的3.4wt％。The active material includes silicon nanosheets, carbon-coated tin nanowires and carbon nanotubes, and the surface of the silicon nanosheets is coated with a carbon layer. The thickness of silicon nanosheets is 50-100nm, and the planar size is 200-1000nm; the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10- 20nm, aspect ratio is (100-200):1. In terms of weight percentage, silicon accounts for 84.6wt% of the active material; tin accounts for 5.1wt% of the active material; carbon accounts for 6.9wt% of the active material; and other substances account for 3.4wt% of the active material.
实施例8Example 8
实施例8与实施例1的区别在于：没有添加碳纳米管和氧化锡。The difference between Example 8 and Example 1 is that no carbon nanotubes and tin oxide are added.
该活性材料包括硅纳米片，且硅纳米片表面包覆有碳层。硅纳米片的厚度为10-80nm，平面尺寸为200-800nm；按照重量百分含量计，硅占活性材料的94.6wt％；锡占活性材料的0wt％；碳占活性材料的4.2wt％；其他物质占活性材料的1.2wt％。The active material includes silicon nanosheets, and the surface of the silicon nanosheets is coated with a carbon layer. The thickness of silicon nanosheets is 10-80nm, and the plane size is 200-800nm; in terms of weight percentage, silicon accounts for 94.6wt% of the active material; tin accounts for 0wt% of the active material; carbon accounts for 4.2wt% of the active material; Other substances account for 1.2 wt% of the active material.
实施例9Example 9
实施例9与实施例1的区别在于：负极材料的制备方法为：The difference between Example 9 and Example 1 is that the preparation method of the negative electrode material is:
(1)将氧化锡纳米颗粒放入高温烧结炉中，在氮气气氛下从室温升到700℃烧结，并通入乙炔气体进行碳包覆，烧结完后即可得到碳包覆锡纳米线。(1) Put the tin oxide nanoparticles into a high-temperature sintering furnace, raise the temperature from room temperature to 700°C for sintering in a nitrogen atmosphere, and introduce acetylene gas for carbon coating. After sintering, carbon-coated tin nanowires can be obtained .
(2)碳纳米管溶液的制备：(2) Preparation of carbon nanotube solution:
将碳纳米管分散在乙醇溶剂中得到碳纳米管溶液，其中，碳纳米管与乙醇的质量比为1:100。The carbon nanotubes are dispersed in an ethanol solvent to obtain a carbon nanotube solution, where the mass ratio of the carbon nanotubes to ethanol is 1:100.
(3)负极活性材料的制备：(3) Preparation of negative active materials:
向碳纳米管溶液中加入太阳能硅片切割废料、碳包覆锡纳米线、聚乙烯吡咯烷酮(PVP)在均质机中均质分散，将均质分散后的悬浊液在砂磨机中砂磨5h，然后过滤、洗涤、烘干后获得均匀分散的活性材料。Add solar silicon wafer cutting waste, carbon-coated tin nanowires, and polyvinylpyrrolidone (PVP) to the carbon nanotube solution, homogeneously disperse it in a homogenizer, and sand the homogeneously dispersed suspension in a sand mill. Grind for 5 hours, then filter, wash, and dry to obtain evenly dispersed active materials.
实施例10Example 10
实施例10与实施例9的区别在于：碳包覆锡纳米线的制备方法为：将锡纳米线置于含有聚四氟乙烯的N-甲基吡咯烷酮溶液中，分散后使锡纳米线表面包覆有粘接层；过滤、干燥后得到前驱体。将前驱体放入高温烧结炉中，在氮气气氛下从室温升到700℃烧结碳化，烧结完后即可得到碳包覆锡纳米线。The difference between Example 10 and Example 9 is that the preparation method of carbon-coated tin nanowires is: placing the tin nanowires in an N-methylpyrrolidone solution containing polytetrafluoroethylene, and after dispersing, the tin nanowires are coated on the surface. Covered with an adhesive layer; filter and dry to obtain the precursor. The precursor is put into a high-temperature sintering furnace and sintered and carbonized under a nitrogen atmosphere from room temperature to 700°C. After sintering, carbon-coated tin nanowires can be obtained.
对比例1Comparative example 1
对比例1与实施例1的区别在于：步骤(3)中，在搅拌得到负极活性物质浆料的过程中，搅拌罐本身不转动。The difference between Comparative Example 1 and Example 1 is that in step (3), during the process of stirring to obtain the negative active material slurry, the stirring tank itself does not rotate.
对比例2Comparative example 2
对比例2与实施例8的区别在于：步骤(3)中，在搅拌得到负极活性物质浆料的过程中，搅拌罐本身不转动。The difference between Comparative Example 2 and Example 8 is that in step (3), during the process of stirring to obtain the negative active material slurry, the stirring tank itself does not rotate.
对比例3Comparative example 3
对比例3与实施例1的区别在于：太阳能硅片切割废料替换成直径80-100nm的硅粉，不能够形成硅纳米片。The difference between Comparative Example 3 and Example 1 is that the solar silicon wafer cutting waste is replaced with silicon powder with a diameter of 80-100 nm, and silicon nanosheets cannot be formed.
该活性材料没有硅纳米片，只有直径80-100nm的硅纳米颗粒，硅表面包覆有碳层。按照重量百分含量计，碳包覆锡纳米线的直径为20-80nm，长径比为(50-500):1；碳纳米管的直径为10-20nm、长径比为(100-200):1。按照重量百分含量计，硅占活性材料的84.3wt％；锡占活性材料的5.3wt％；碳占活性材料的5.7wt％；其他物质占活性材料的3.7wt％。
The active material does not have silicon nanosheets, only silicon nanoparticles with a diameter of 80-100nm, and the silicon surface is coated with a carbon layer. In terms of weight percentage, the diameter of carbon-coated tin nanowires is 20-80nm, and the aspect ratio is (50-500):1; the diameter of carbon nanotubes is 10-20nm, and the aspect ratio is (100-200). ):1. In terms of weight percentage, silicon accounts for 84.3wt% of the active material; tin accounts for 5.3wt% of the active material; carbon accounts for 5.7wt% of the active material; and other substances account for 3.7wt% of the active material.
综上，实施例1-实施例10以及对比例1-对比例3提供的负极极片如表1所示。In summary, the negative electrode plates provided in Examples 1 to 10 and Comparative Examples 1 to 3 are as shown in Table 1.
表1负极极片
Table 1 Negative pole piece
Table 1 Negative pole piece
其中，硅基纳米片的尺寸、碳包覆锡纳米线的尺寸、碳纳米管的尺寸以及硅基纳米片的排布均通过扫描电镜(SEM)图观察得到。Among them, the size of the silicon-based nanosheets, the size of the carbon-coated tin nanowires, the size of the carbon nanotubes, and the arrangement of the silicon-based nanosheets were all observed through scanning electron microscopy (SEM) images.
硅含量、锡含量以及碳含量通过电感耦合等离子体光谱仪和硫碳分析仪等进行检测得到。图1为本申请实施例1提供的负极极片(原始极片)的扫描电镜(SEM)图，请参阅图1，该原始极片内部存在部分空隙，极片具有一定的孔隙率，硅纳米片之间存在线状结构，且硅纳米片倾向于平行排列形成叠层结构，同时更倾向于平行集流体方向平行排列。The silicon content, tin content and carbon content are detected by inductively coupled plasma spectrometer and sulfur carbon analyzer. Figure 1 is a scanning electron microscope (SEM) image of the negative pole piece (original pole piece) provided in Example 1 of the present application. Please refer to Figure 1. There are some gaps inside the original pole piece, and the pole piece has a certain porosity. Silicon nanoparticles There is a linear structure between the sheets, and the silicon nanosheets tend to be arranged in parallel to form a stacked structure, and they also tend to be arranged in parallel in the direction of the current collector.
图2为本申请实施例1提供的负极极片(第五周嵌锂态)的扫描电镜(SEM)图，请参阅图2，在
嵌锂过程中，硅纳米片沿着厚度方向发生体积变化和滑动，同时填满极片内部空隙，硅纳米片继续以二维层状结构堆叠在一起，保持了极片的良好电接触和完整性。Figure 2 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth cycle of lithium insertion state) provided in Example 1 of the present application. Please refer to Figure 2. During the lithium insertion process, the silicon nanosheets undergo volume changes and slide along the thickness direction, while filling the internal gaps of the pole pieces. The silicon nanosheets continue to be stacked together in a two-dimensional layered structure, maintaining good electrical contact and integrity of the pole pieces. sex.
图3为对比例1提供的负极极片(原始极片)的扫描电镜(SEM)图，请参阅图3，该原始极片内部存在部分空隙，极片具有一定的孔隙率，硅纳米片之间存在线状结构，且硅纳米片无规则排列。Figure 3 is a scanning electron microscope (SEM) image of the negative pole piece (original pole piece) provided in Comparative Example 1. Please refer to Figure 3. There are some gaps inside the original pole piece, and the pole piece has a certain porosity. Among the silicon nanosheets There is a linear structure between them, and the silicon nanosheets are arranged irregularly.
图4为对比例1提供的负极极片(第五周嵌锂态)的扫描电镜(SEM)图，请参阅图4，由于硅纳米片无规则排列，在嵌锂过程中，硅纳米片沿着厚度方向发生体积变化和滑动，其不能够填满极片内部空隙，并且无规则分布在活性材料层中。Figure 4 is a scanning electron microscope (SEM) image of the negative electrode plate (in the fifth week of lithium insertion state) provided in Comparative Example 1. Please refer to Figure 4. Since the silicon nanosheets are irregularly arranged, during the lithium insertion process, the silicon nanosheets move along the Volume changes and sliding occur in the thickness direction, which cannot fill the internal gaps of the pole piece, and are randomly distributed in the active material layer.
图5为本申请实施例1提供的活性材料的X射线衍射(XRD)图，图6为本申请实施例1提供的负极极片在辊压前的X射线衍射(XRD)图，图7为本申请实施例1提供的负极极片在辊压后的X射线衍射(XRD)图。其中为了避免铜箔中铜峰位太强的影响，涂布过程中在铜箔上先涂布一层PVDF，测试XRD时，先去掉铜箔。从图5可以看出，(111)/(220)晶面峰强＝2.27，(111)/(311)晶面峰强＝3.89；从图6可以看出，(111)/(220)晶面峰强＝2.30，(111)/(311)晶面峰强＝4.27；从图7可以看出，(111)/(220)晶面峰强＝2.39，(111)/(311)晶面峰强＝4.35。辊压后的极片的(111)/(220)晶面峰强与(111)/(311)晶面峰强的值均增大，说明辊压后的极片具有较好的性能，硅纳米片与负极集流体之间的夹角较小，硅纳米片倾向于与负极集流体平行。Figure 5 is an X-ray diffraction (XRD) pattern of the active material provided in Example 1 of the application. Figure 6 is an X-ray diffraction (XRD) pattern of the negative electrode plate provided in Example 1 of the application before rolling. Figure 7 is The X-ray diffraction (XRD) pattern of the negative electrode sheet after rolling provided in Example 1 of the present application. In order to avoid the influence of too strong copper peaks in the copper foil, a layer of PVDF is first coated on the copper foil during the coating process. When testing XRD, the copper foil is first removed. As can be seen from Figure 5, the (111)/(220) crystal plane peak intensity = 2.27, (111)/(311) crystal plane peak intensity = 3.89; as can be seen from Figure 6, the (111)/(220) crystal plane peak intensity Surface peak intensity = 2.30, (111)/(311) crystal surface peak intensity = 4.27; as can be seen from Figure 7, (111)/(220) crystal surface peak intensity = 2.39, (111)/(311) crystal surface Peak strength=4.35. The values of the (111)/(220) crystal plane peak intensity and the (111)/(311) crystal plane peak intensity of the rolled pole piece both increase, indicating that the rolled pole piece has better performance. Silicon The angle between the nanosheets and the negative electrode current collector is small, and the silicon nanosheets tend to be parallel to the negative electrode current collector.
图8为本申请实施例1提供的半电池的充放电曲线图，从图8可以看出，实施例1提供的半电池的首周容量高达3000mAh/g，首周库伦效率高达90％。Figure 8 is a charge-discharge curve of the half-cell provided in Embodiment 1 of the present application. It can be seen from Figure 8 that the first-cycle capacity of the half-cell provided in Embodiment 1 is as high as 3000 mAh/g, and the first-cycle Coulombic efficiency is as high as 90%.
图9为本申请实施例1提供的负极活性材料的扫描电镜(SEM)图，图10为本申请实施例9提供的负极活性材料的扫描电镜(SEM)图，图11为本申请实施例1提供的电池循环5周后的负极活性材料的扫描电镜(SEM)图，图12为对比例3提供的负极活性材料的扫描电镜(SEM)图。从图9和图10可以看出，实施例1和实施例9的负极活性材料中的碳包覆锡纳米线、硅纳米片和碳纳米管混合形成了三维网络结构，且图9中的负极活性材料的碳包覆锡纳米线以及碳纳米管可以更加均匀分散在硅纳米片表面，以在硅纳米片表面形成三维离子导电网络结构；同时，图9提供的负极活性材料中，通过将氧化锡纳米颗粒均匀分散在硅纳米片的表面，再原位还原和均匀生长碳包覆锡纳米线，可以弥补硅的粒子电导，结合碳纳米管和硅纳米片形成三维导电网络，以使负极活性材料的离子电导和电子电导的效果均较佳。从图11可以看出，实施例1提供的电池循环5周后，硅纳米片表面的锡纳米线基本存在，负极材料循环后锡纳米线依然可以很好的分布在硅纳米片的表面。从图12可以看出，硅纳米颗粒表面容易形成锡颗粒，不易形成锡纳米线。Figure 9 is a scanning electron microscope (SEM) picture of the negative active material provided in Example 1 of the present application. Figure 10 is a scanning electron microscope (SEM) picture of the negative active material provided in Example 9 of the present application. Figure 11 is a SEM picture of the negative active material provided in Example 1 of the present application. A scanning electron microscope (SEM) image of the negative electrode active material after 5 weeks of battery cycling is provided. FIG. 12 is a scanning electron microscope (SEM) image of the negative electrode active material provided in Comparative Example 3. It can be seen from Figures 9 and 10 that the carbon-coated tin nanowires, silicon nanosheets and carbon nanotubes in the negative active materials of Examples 1 and 9 are mixed to form a three-dimensional network structure, and the negative electrode in Figure 9 The carbon-coated tin nanowires and carbon nanotubes of the active materials can be more evenly dispersed on the surface of the silicon nanosheets to form a three-dimensional ion conductive network structure on the surface of the silicon nanosheets; at the same time, in the negative active material provided in Figure 9, by oxidizing Tin nanoparticles are evenly dispersed on the surface of silicon nanosheets, and then carbon-coated tin nanowires are reduced and uniformly grown in situ, which can compensate for the particle conductivity of silicon, and combine carbon nanotubes and silicon nanosheets to form a three-dimensional conductive network to make the negative electrode active. The ion conductivity and electronic conductivity of the material are both better. It can be seen from Figure 11 that after the battery provided in Example 1 was cycled for 5 weeks, the tin nanowires on the surface of the silicon nanosheets basically existed, and the tin nanowires could still be well distributed on the surface of the silicon nanosheets after the negative electrode material was cycled. It can be seen from Figure 12 that tin particles are easily formed on the surface of silicon nanoparticles, but tin nanowires are not easily formed.
图13为本申请实施例1提供的碳包覆锡纳米线的透射电镜(TEM)图；图14为本申请实施例10提供的碳包覆锡纳米线的透射电镜(TEM)图。从图13中可以看出，实施例1中锡纳米线的表面包覆的碳层的微观结构是一条条平行的线状结构，相邻的两条线状结构之间的距离为d002的值为0.33564，通过公式γ＝(0.344-d002)/(0.344-0.3354)(公式中的参数的单位均为nm)可以计算出石墨化度γ的值＝(0.344-0.33564)/(0.344-0.3354)＝0.972。图14可以看出，实施例10中锡纳米线的表面包覆的碳层的微观结构不规则，说明其石墨化程度不高。Figure 13 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 1 of the application; Figure 14 is a transmission electron microscope (TEM) image of the carbon-coated tin nanowire provided in Example 10 of the application. As can be seen from Figure 13, the microstructure of the carbon layer coated on the surface of the tin nanowires in Example 1 is a parallel linear structure, and the distance between two adjacent linear structures is d 002 The value is 0.33564. The value of graphitization degree γ can be calculated through the formula γ = (0.344-d 002 )/(0.344-0.3354) (the units of the parameters in the formula are all nm) = (0.344-0.33564)/(0.344- 0.3354)=0.972. It can be seen from Figure 14 that the microstructure of the carbon layer coated on the surface of the tin nanowires in Example 10 is irregular, indicating that the degree of graphitization is not high.
图15为本申请实施例1以及实施例9提供的电池的阻抗图，从图15可以看出，实施例9提供的负极活性材料制备得到的电池的阻抗是实施例1提供的负极活性材料制备得到的电池的阻抗的2.5倍，说明实施例1提供的负极活性材料具有更加优异的导电性。Figure 15 is an impedance diagram of the battery provided in Example 1 and Example 9 of the present application. It can be seen from Figure 15 that the impedance of the battery prepared from the negative active material provided in Example 9 is the same as that prepared from the negative active material provided in Example 1. The resistance of the obtained battery is 2.5 times, indicating that the negative active material provided in Example 1 has more excellent conductivity.
图16为本申请实施例1提供的电池在2C条件下的循环性能图。从图16可以看出，本申请实施例
1提供的电池能够稳定循环1000周，容量能稳定在700mAh/g。Figure 16 is a cycle performance diagram of the battery provided in Example 1 of the present application under 2C conditions. It can be seen from Figure 16 that the embodiment of this application 1The battery provided can cycle stably for 1000 cycles, and the capacity can be stabilized at 700mAh/g.
循环容量保持率和首周体积膨胀率Cycle capacity retention rate and first-week volume expansion rate
使用蓝电充放电测试仪对半电池进行恒电流充放电，其中截止电压设置为0.005-1.0V，倍率设定为0.2C，测试其首周充电容量、首周库伦效率、第100周充电容量、第100周库伦效率。Use a blue battery charge and discharge tester to perform constant current charge and discharge on the half cell, with the cutoff voltage set to 0.005-1.0V and the rate set to 0.2C. Test its first week charging capacity, first week Coulombic efficiency, and 100th week charging capacity. , Coulomb efficiency in the 100th week.
通过以下公式算出100周的循环容量保持率。Calculate the cycle capacity retention rate for 100 cycles using the following formula.
100周的循环容量保持率＝第100周的充电容量/首周的充电容量×100％。The cycle capacity retention rate of 100 cycles = the charging capacity of the 100th cycle / the charging capacity of the first week × 100%.
首周体积膨胀率：用千分尺分别测试原始极片厚度h1和首周完全嵌锂态极片的厚度h2。Volume expansion rate in the first week: Use a micrometer to measure the original pole piece thickness h1 and the thickness h2 of the fully lithium-embedded pole piece in the first week.
首周体积膨胀率＝(h2-h1)/h1Volume expansion rate in the first week = (h2-h1)/h1
各实施例和对比例首周充电比容量、首周库伦效率、第100周库伦效率及100周的循环容量保持率数据如表2所示。The charging specific capacity in the first week, Coulombic efficiency in the first week, Coulombic efficiency in the 100th week and cycle capacity retention rate data in the 100th week of each embodiment and comparative example are shown in Table 2.
表2半电池的电学性能
Table 2 Electrical properties of half cells
Table 2 Electrical properties of half cells
结合表1和表2可知，使用本申请实施例提供的负极极片制备得到的半电池，其首周充电容量都大于1500mAh/g，100周后循环保持率大于90％，首周体积膨胀率都小于130％，综合性能较佳。而使用对比例提供的负极极片制备的半电池，其体积膨胀率都非常高，且循环保持率较低。Combining Table 1 and Table 2, it can be seen that the half-battery prepared using the negative electrode sheet provided in the embodiment of the present application has a charging capacity greater than 1500 mAh/g in the first week, a cycle retention rate greater than 90% after 100 weeks, and a volume expansion rate in the first week. Both are less than 130%, indicating better overall performance. The volume expansion rate of the half-battery prepared using the negative electrode sheet provided in the comparative example is very high, and the cycle retention rate is low.
实施例1和实施例9对比可知，实施例1提供的负极活性材料制备电池以后，其首周充电容量和循
环保持率均较高，说明将硅纳米片和碳纳米管与氧化锡颗粒混合以后，在高温条件下通入乙炔气体进行反应，可以形成石墨化度较高的碳包覆锡纳米线的同时，使三者的混合更加均匀，得到性能更好的负极活性材料。Comparing Example 1 and Example 9, it can be seen that after the battery is prepared from the negative active material provided in Example 1, its first-week charging capacity and cycle rate are The ring retention rates are all high, indicating that after mixing silicon nanosheets and carbon nanotubes with tin oxide particles, acetylene gas is introduced under high temperature conditions for reaction, and carbon-coated tin nanowires with a high degree of graphitization can be formed. , making the mixing of the three more uniform, and obtaining a negative active material with better performance.
实施例9和实施例10对比可知，实施例9提供的负极活性材料制备电池以后，其首周充电容量和循环保持率均较高。说明相较于实施例10直接在锡纳米线的表面碳化有机粘结剂形成碳层，实施例9在高温条件下通入乙炔气体，可以形成石墨化度较高的碳包覆锡纳米线，在后续与硅纳米片和碳纳米管混合以后，得到的负极活性材料性能较好。Comparing Example 9 and Example 10, it can be seen that after the battery is prepared from the negative active material provided in Example 9, its first-week charging capacity and cycle retention rate are both higher. It shows that compared with Example 10 where the organic binder is directly carbonized on the surface of the tin nanowires to form a carbon layer, Example 9 can form carbon-coated tin nanowires with a higher degree of graphitization by passing acetylene gas under high temperature conditions. After subsequent mixing with silicon nanosheets and carbon nanotubes, the resulting negative active material has better performance.
倍率性能Rate performance
使用蓝电充放电仪对扣电进行恒电流充放电，其中截止电压设置为0.005-1.0V，分别依次在0.1C、0.2C、0.5C、1C、0.2C倍率下进行测试。Use a blue battery charging and discharging instrument to perform constant current charging and discharging on the buckle, with the cut-off voltage set to 0.005-1.0V, and the tests are conducted at 0.1C, 0.2C, 0.5C, 1C, and 0.2C rate respectively.
通过以下公式不同倍率下容量保持率。The capacity retention rate under different rates is calculated by the following formula.
倍率容量保持率＝该倍率下的充电容量/0.1C倍率充电容量×100％。Rate capacity retention rate = charging capacity at this rate/0.1C rate charging capacity × 100%.
各实施例和对比例不同倍率下容量保持率数据如表3所示。The capacity retention rate data of various examples and comparative examples at different rates are shown in Table 3.
表3半电池的倍率性能
Table 3 Rate performance of half cells
Table 3 Rate performance of half cells
结合表1和表3可知，使用本申请实施例提供的负极极片制备得到的半电池，其1C倍率下容量保持率都大于65％；而使用对比例提供的负极极片制备的半电池，1C倍率下容量保持率基本都小于40％。
Combining Table 1 and Table 3, it can be seen that the capacity retention rate of the half-battery prepared using the negative electrode sheet provided in the embodiment of the present application is greater than 65% at 1C rate; while the half-battery prepared using the negative electrode sheet provided in the comparative example has a capacity retention rate of more than 65%. The capacity retention rate at 1C rate is basically less than 40%.
实施例1和实施例9对比可知，实施例1提供的负极活性材料制备电池以后，其倍率性能更佳，说明将硅纳米片和碳纳米管与氧化锡颗粒混合以后，在高温条件下通入乙炔气体进行反应，可以形成石墨化度较高的碳包覆锡纳米线的同时，使三者的混合更加均匀，得到性能更好的负极活性材料。Comparing Example 1 and Example 9, it can be seen that after the negative active material provided in Example 1 is used to prepare a battery, its rate performance is better, indicating that after mixing silicon nanosheets and carbon nanotubes with tin oxide particles, they are introduced under high temperature conditions. The reaction of acetylene gas can form carbon-coated tin nanowires with a higher degree of graphitization and at the same time make the mixing of the three more uniform, resulting in a negative active material with better performance.
实施例9和实施例10对比可知，实施例9提供的负极活性材料制备电池以后，其倍率性能较好。说明相较于实施例10直接在锡纳米线的表面碳化有机粘结剂形成碳层，实施例9在高温条件下通入乙炔气体，可以形成石墨化度较高的碳包覆锡纳米线，在后续与硅纳米片和碳纳米管混合以后，得到的负极活性材料性能较好。Comparing Example 9 and Example 10, it can be seen that after the negative active material provided in Example 9 is used to prepare a battery, its rate performance is better. It shows that compared with Example 10 where the organic binder is directly carbonized on the surface of the tin nanowires to form a carbon layer, Example 9 can form carbon-coated tin nanowires with a higher degree of graphitization by passing acetylene gas under high temperature conditions. After subsequent mixing with silicon nanosheets and carbon nanotubes, the resulting negative active material has better performance.
在实施例1的基础上，分别改变太阳能硅和锡的比例、球磨时间、硅种类，其它的条件不变，按照实施例1的方法制备活性材料，然后再将活性材料按照实施例1中制备扣式半电池的方法制备得到1-13号电池，并按照电化学性能测试方法对电池进行充放电循环性能测试，结果见表4。On the basis of Example 1, the ratio of solar silicon and tin, ball milling time, and silicon type were changed respectively, and other conditions remained unchanged. The active material was prepared according to the method of Example 1, and then the active material was prepared according to Example 1. Batteries No. 1-13 were prepared using the button half cell method, and the charge and discharge cycle performance of the batteries were tested according to the electrochemical performance testing method. The results are shown in Table 4.
表4半电池的电学性能
Table 4 Electrical properties of half cells
Table 4 Electrical properties of half cells
从表4可以看出，太阳能硅片切割废料及单晶硅的效果明显优于其他种类的硅，电镜照片结果也表明太阳能硅片切割废料砂磨后会形成纳米片状结构。硅质量占比70％～98％其表现比较好的电化学性能，砂磨时间优选在4h以上。It can be seen from Table 4 that the effect of solar silicon wafer cutting waste and single crystal silicon is significantly better than other types of silicon. The results of electron microscopy also show that the solar silicon wafer cutting waste will form a nanosheet structure after sanding. Silicon mass accounts for 70% to 98%, which has better electrochemical performance, and the sanding time is preferably more than 4 hours.
表5为实施例1提供的负极极片(活性材料包括硅纳米片)辊压前后及原材料，以及对比例3提供的负极极片(活性材料包括硅纳米颗粒)辊压前后及原材料的XRD图的分析结果。Table 5 shows the XRD patterns of the negative electrode sheet (the active material includes silicon nanosheets) before and after rolling and the raw materials provided in Example 1, and the XRD patterns of the negative electrode sheet (the active material includes silicon nanoparticles) before and after rolling and the raw materials provided in Comparative Example 3. analysis results.
表5负极极片的XRD图的分析结果
Table 5 Analysis results of XRD pattern of negative electrode plate
Table 5 Analysis results of XRD pattern of negative electrode plate
通过X射线衍射对实施例1和对比例3的未辊压和辊压后极片进行测试，结果表明，实施例1中，从原材料到制作成极片，再进行辊压，(111)/(220)晶面峰强和(111)/(311)晶面峰强比值逐渐在增大，说明极片中的纳米片逐渐倾向平行排列，与SEM相对应，而对比例3中从原材料到制作成极片，再进行辊压，(111)/(220)晶面峰强和(111)/(311)晶面峰强比值基本不变。The non-rolled and rolled pole pieces of Example 1 and Comparative Example 3 were tested by X-ray diffraction. The results showed that in Example 1, from raw materials to pole pieces produced and then rolled, (111)/ The (220) crystal plane peak intensity and the (111)/(311) crystal plane peak intensity ratio are gradually increasing, indicating that the nanosheets in the pole piece gradually tend to be arranged in parallel, corresponding to SEM, while in Comparative Example 3, from raw materials to After making the pole piece and then rolling it, the peak intensity ratio of (111)/(220) crystal plane and the peak intensity of (111)/(311) crystal plane remain basically unchanged.
以上所描述的实施例是本申请一部分实施例，而不是全部的实施例。本申请的实施例的详细描述并非旨在限制要求保护的本申请的范围，而是仅仅表示本申请的选定实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
The above-described embodiments are part of the embodiments of the present application, but not all of the embodiments. The detailed description of the embodiments of the application is not intended to limit the scope of the application as claimed, but rather to represent selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.
Claims (12)
- 一种负极极片，其中，包括负极集流体以及设置于所述负极集流体表面的负极活性材料层；A negative electrode sheet, which includes a negative electrode current collector and a negative electrode active material layer disposed on the surface of the negative electrode current collector;所述负极活性材料层中的活性材料包括片状硅基材料，以所述负极集流体的表面为基准，至少60％的所述片状硅基材料与所述负极集流体的表面的夹角≤20°。The active material in the negative active material layer includes a sheet-shaped silicon-based material, and based on the surface of the negative electrode current collector, at least 60% of the angle between the sheet-shaped silicon-based material and the surface of the negative electrode current collector ≤20°.
- 根据权利要求1所述的负极极片，其中，所述片状硅基材料为硅纳米片、硅亚微米片、硅合金纳米片、硅合金亚微米片、硅氧纳米片和硅氧亚微米片及其表面改性包覆后的材料的一种或多种；The negative electrode sheet according to claim 1, wherein the sheet-shaped silicon-based material is silicon nanosheets, silicon submicron sheets, silicon alloy nanosheets, silicon alloy submicron sheets, silicon oxygen nanosheets and silicon oxygen submicron sheets. One or more materials after the sheet and its surface are modified and coated;或/和，所述硅纳米片的厚度1-200nm；平面尺寸为20-5000nm。Or/and, the thickness of the silicon nanosheet is 1-200nm; the planar size is 20-5000nm.
- 根据权利要求1所述负极极片，其中，所述活性材料还包括碳包覆锡纳米线作为协同活性材料；The negative electrode piece according to claim 1, wherein the active material further includes carbon-coated tin nanowires as a synergistic active material;或/和，所述碳包覆锡纳米线的直径在100nm以下，长径比为(5-1000):1。Or/and, the diameter of the carbon-coated tin nanowire is below 100 nm, and the aspect ratio is (5-1000):1.
- 据权利要求3所述负极极片，其中，所述碳包覆锡纳米线是通过原位还原氧化锡纳米颗粒和碳沉积形成的。The negative electrode sheet of claim 3, wherein the carbon-coated tin nanowires are formed by in-situ reduction of tin oxide nanoparticles and carbon deposition.
- 据权利要求3所述负极极片，其中，所述碳包覆锡纳米线中碳包覆层的石墨化度γ满足0.3≦γ≦1，其中γ＝(0.344-d002)/(0.344-0.3354)，d002为碳包覆层在002晶面的纳米层间距。The negative electrode sheet according to claim 3, wherein the graphitization degree γ of the carbon coating layer in the carbon-coated tin nanowire satisfies 0.3≦γ≦1, where γ=(0.344-d002)/(0.344-0.3354 ), d002 is the nano-layer spacing of the carbon coating layer on the 002 crystal plane.
- 据权利要求1-5任一项所述负极极片，其中，所述活性材料还包括碳纳米管作为协同活性材料；The negative electrode sheet according to any one of claims 1 to 5, wherein the active material further includes carbon nanotubes as a synergistic active material;或/和，所述碳纳米管的直径在20nm以下，长径比为(10-1000):1；Or/and, the diameter of the carbon nanotube is below 20 nm, and the aspect ratio is (10-1000): 1;或/和，所述碳纳米管至少包括单壁碳纳米管。Or/and, the carbon nanotubes at least include single-walled carbon nanotubes.
- 根据权利要求1所述的负极极片，其中，以活性材料、导电剂和粘结剂三者质量和为总质量，所述活性材料质量占总质量的百分数为70％-95％，所述导电剂质量占总质量的百分数为0％-10％，所述粘结剂质量占总质量的百分数为2％-30％。The negative electrode sheet according to claim 1, wherein the mass sum of the active material, conductive agent and binder is the total mass, and the mass of the active material accounts for 70%-95% of the total mass. The mass of the conductive agent accounts for 0%-10% of the total mass, and the mass of the binder accounts for 2%-30% of the total mass.
- 根据权利要求7所述的负极极片，其中，所述活性材料中，硅的重量百分含量为50％-98％，锡的重量百分含量为0.5％-20％，碳的重量百分含量为1.5-20％。The negative electrode sheet according to claim 7, wherein the weight percentage of silicon in the active material is 50%-98%, the weight percentage of tin is 0.5%-20%, and the weight percentage of carbon is Content is 1.5-20%.
- 一种锂离子二次电池，其中，包括权利要求1-8任一项所述的负极极片。A lithium ion secondary battery, including the negative electrode sheet according to any one of claims 1 to 8.
- 一种固态电池，其中，包括权利要求1-9任一项所述的负极极片。A solid-state battery, comprising the negative electrode sheet according to any one of claims 1-9.
- 一种负极材料的制备方法，其中，将碳纳米管溶液、硅基材料、氧化锡纳米颗粒分散在有机溶剂中进行研磨、过滤、干燥后得到复合前驱体，将所述复合前驱体置于高温烧结炉中，在惰性气氛中升温至650-900℃，然后通入乙炔气体进行烧结，得到碳纳米管、碳包覆锡纳米线和片状硅基材料混合的负极材料；A method for preparing negative electrode materials, wherein carbon nanotube solution, silicon-based material, and tin oxide nanoparticles are dispersed in an organic solvent, ground, filtered, and dried to obtain a composite precursor, and the composite precursor is placed at high temperature In the sintering furnace, the temperature is raised to 650-900°C in an inert atmosphere, and then acetylene gas is introduced for sintering to obtain a negative electrode material mixed with carbon nanotubes, carbon-coated tin nanowires and flaky silicon-based materials;可选地，所述碳纳米管的直径在20nm以下，长径比为(10-1000):1；Optionally, the diameter of the carbon nanotube is below 20 nm, and the aspect ratio is (10-1000): 1;可选地，所述碳纳米管至少包括单壁碳纳米管；Optionally, the carbon nanotubes include at least single-walled carbon nanotubes;可选地，所述碳包覆锡纳米线的直径在100nm以下，长径比为(5-1000):1；Optionally, the diameter of the carbon-coated tin nanowire is below 100 nm, and the aspect ratio is (5-1000): 1;可选地，所述片状硅基材料为硅纳米片、硅亚微米片、硅合金纳米片、硅合金亚微米片、硅氧纳米 片和硅氧亚微米片及其表面改性包覆后的材料的一种或多种；Optionally, the sheet-like silicon-based material is silicon nanosheets, silicon submicron sheets, silicon alloy nanosheets, silicon alloy submicron sheets, silicon-oxygen nanosheets. One or more of silica submicron flakes and silicon-oxygen submicron flakes and their surface-modified and coated materials;可选地，所述硅纳米片的厚度1-200nm；平面尺寸为20-5000nm；Optionally, the thickness of the silicon nanosheet is 1-200nm; the planar size is 20-5000nm;可选地，所述负极材料中，硅的重量百分含量为50％-98％，锡的重量百分含量为0.5％-20％，碳的重量百分含量为1.5-20％。Optionally, in the negative electrode material, the weight percentage of silicon is 50%-98%, the weight percentage of tin is 0.5%-20%, and the weight percentage of carbon is 1.5-20%.
- 一种负极极片的制备方法，其中，将片状硅基材料、导电剂、粘结剂和溶剂混合置于搅拌罐中，然后搅拌罐中的搅拌器以200-3000rad/min的速度不断搅拌，且搅拌罐本身以200-3000rad/min的速度不断转动，以得到负极活性浆料；A method for preparing a negative electrode sheet, in which a sheet-shaped silicon-based material, a conductive agent, a binder and a solvent are mixed and placed in a stirring tank, and then the stirrer in the stirring tank is continuously stirred at a speed of 200-3000rad/min. , and the mixing tank itself continuously rotates at a speed of 200-3000rad/min to obtain the negative active slurry;然后将所述负极活性浆料涂覆在负极集流体的表面、干燥、辊压后得到负极极片；Then, the negative electrode active slurry is coated on the surface of the negative electrode current collector, dried, and rolled to obtain a negative electrode piece;可选地，所述片状硅基材料为硅纳米片、硅亚微米片、硅合金纳米片、硅合金亚微米片、硅氧纳米片和硅氧亚微米片及其表面改性包覆后的材料的一种或多种；Optionally, the sheet-shaped silicon-based material is silicon nanosheets, silicon submicron sheets, silicon alloy nanosheets, silicon alloy submicron sheets, silicon-oxygen nanosheets and silicon-oxygen submicron sheets, and after surface modification and coating thereof one or more materials;可选地，所述硅纳米片的厚度1-200nm；平面尺寸为20-5000nm。 Optionally, the silicon nanosheet has a thickness of 1-200 nm and a planar size of 20-5000 nm.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210446207.6 | 2022-04-26 | ||
| CN202210446207.6A CN114944465A (en) | 2022-04-26 | 2022-04-26 | Negative pole piece and battery |
| CN202310456477.X | 2023-04-24 | ||
| CN202310456477.XA CN116705988A (en) | 2022-04-26 | 2023-04-24 | Negative electrode plate and preparation method thereof, battery and preparation method of negative electrode material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2023208058A1 true WO2023208058A1 (en) | 2023-11-02 |
Family
ID=82906258
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/CN2023/090928 WO2023208058A1 (en) | 2022-04-26 | 2023-04-26 | Negative electrode sheet, preparation method therefor, battery, and preparation method for negative electrode material |
Country Status (2)
| Country | Link |
|---|---|
| CN (2) | CN114944465A (en) |
| WO (1) | WO2023208058A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114944465A (en) * | 2022-04-26 | 2022-08-26 | 松山湖材料实验室 | Negative pole piece and battery |
| CN117117094A (en) * | 2023-02-15 | 2023-11-24 | 荣耀终端有限公司 | Negative plate, preparation method thereof, battery cell and battery |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110206986A1 (en) * | 2010-02-23 | 2011-08-25 | Samsung Sdi Co., Ltd., | Negative active material for rechargeable lithium battery and rechargeable lithium battery including the same |
| CN104549017A (en) * | 2013-10-29 | 2015-04-29 | 无锡华臻新能源科技有限公司 | Stirring device for lithium ion battery electrode slurry |
| CN110559898A (en) * | 2019-09-23 | 2019-12-13 | 大同新成新材料股份有限公司 | preparation device and preparation method of composite negative electrode material for lithium battery |
| CN111048763A (en) * | 2019-12-20 | 2020-04-21 | 中国科学院物理研究所 | Nano tin-silicon composite anode material and preparation method and application thereof |
| WO2021120155A1 (en) * | 2019-12-20 | 2021-06-24 | 中国科学院物理研究所 | Nano-tin-silicon composite negative electrode material, and preparation method therefor and use thereof |
| CN113728462A (en) * | 2019-06-28 | 2021-11-30 | 株式会社Lg新能源 | Negative electrode and secondary battery comprising same |
| CN114944465A (en) * | 2022-04-26 | 2022-08-26 | 松山湖材料实验室 | Negative pole piece and battery |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8936874B2 (en) * | 2008-06-04 | 2015-01-20 | Nanotek Instruments, Inc. | Conductive nanocomposite-based electrodes for lithium batteries |
| JP2011023316A (en) * | 2009-07-21 | 2011-02-03 | Panasonic Corp | Negative electrode of lithium-ion secondary battery and method of manufacturing the same, as well as lithium-ion secondary battery using the same |
| US10957905B2 (en) * | 2017-11-02 | 2021-03-23 | Unimaterial Technologies, Llc | Porous silicon flake anode material for li ion batteries |
-
2022
- 2022-04-26 CN CN202210446207.6A patent/CN114944465A/en active Pending
-
2023
- 2023-04-24 CN CN202310456477.XA patent/CN116705988A/en active Pending
- 2023-04-26 WO PCT/CN2023/090928 patent/WO2023208058A1/en unknown
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110206986A1 (en) * | 2010-02-23 | 2011-08-25 | Samsung Sdi Co., Ltd., | Negative active material for rechargeable lithium battery and rechargeable lithium battery including the same |
| CN104549017A (en) * | 2013-10-29 | 2015-04-29 | 无锡华臻新能源科技有限公司 | Stirring device for lithium ion battery electrode slurry |
| CN113728462A (en) * | 2019-06-28 | 2021-11-30 | 株式会社Lg新能源 | Negative electrode and secondary battery comprising same |
| CN110559898A (en) * | 2019-09-23 | 2019-12-13 | 大同新成新材料股份有限公司 | preparation device and preparation method of composite negative electrode material for lithium battery |
| CN111048763A (en) * | 2019-12-20 | 2020-04-21 | 中国科学院物理研究所 | Nano tin-silicon composite anode material and preparation method and application thereof |
| WO2021120155A1 (en) * | 2019-12-20 | 2021-06-24 | 中国科学院物理研究所 | Nano-tin-silicon composite negative electrode material, and preparation method therefor and use thereof |
| CN114944465A (en) * | 2022-04-26 | 2022-08-26 | 松山湖材料实验室 | Negative pole piece and battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114944465A (en) | 2022-08-26 |
| CN116705988A (en) | 2023-09-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zheng et al. | Fabrication and understanding of Cu 3 Si-Si@ carbon@ graphene nanocomposites as high-performance anodes for lithium-ion batteries | |
| EP3326230B1 (en) | Silicon-carbon composite particulate material | |
| CN111180691B (en) | Double-layer carbon-coated silicon-based composite material and preparation method and application thereof | |
| Wang et al. | Onion-like carbon matrix supported Co 3 O 4 nanocomposites: a highly reversible anode material for lithium ion batteries with excellent cycling stability | |
| WO2023208058A1 (en) | Negative electrode sheet, preparation method therefor, battery, and preparation method for negative electrode material | |
| CN105247707B (en) | Electrod composition, electrochemical cell and the method for preparing electrochemical cell | |
| CN107305941B (en) | Lithium-carbon composite material, preparation method and application thereof, and lithium compensation method | |
| WO2014032595A1 (en) | Negative electrode material, method for producing the same, negative electrode, and battery comprising the same | |
| KR20210079442A (en) | Anode material with graphene-mxene-silicon of secondary battery and the method thereof | |
| Zhang et al. | Silicon-multi-walled carbon nanotubes-carbon microspherical composite as high-performance anode for lithium-ion batteries | |
| Zhang et al. | A compact silicon–carbon composite with an embedded structure for high cycling coulombic efficiency anode materials in lithium-ion batteries | |
| WO2019019410A1 (en) | Modified lithium-free anode, method for preparing same, and lithium-ion battery comprising same | |
| KR102228769B1 (en) | Anode material with graphene-agnw-silicon of secondary battery and the method thereof | |
| JP7452599B2 (en) | Composite active material for lithium secondary batteries | |
| KR102405622B1 (en) | Anode material with graphene-cnt-silicon coreshell of secondary battery and the method thereof | |
| CN110098402B (en) | Silicon-carbon negative electrode material for lithium ion battery and preparation method thereof | |
| KR102176590B1 (en) | Method of preparing anode active material for rechargeable lithium battery and rechargeable lithium battery | |
| WO2023016047A1 (en) | Negative electrode material and preparation method therefor, lithium ion battery | |
| KR102473745B1 (en) | Manufacturing method of Silicon/Carbon nanotube/Graphene Composite film as Anode Materials for Lithiumion Batteries and Manufacturing method for Lithiumion Batteries using it | |
| CN112635723B (en) | Lithium ion battery negative electrode active material, lithium ion battery negative electrode and lithium ion battery | |
| WO2023206592A1 (en) | Negative electrode plate and battery | |
| KR20210118319A (en) | Anode material with graphene-mxene-silicon of secondary battery and the method thereof | |
| CN114937772B (en) | Negative electrode material, negative electrode plate and lithium ion battery | |
| Pan et al. | Ag nanoparticle modified porous Si microspheres as high-performance anodes for Li-ion batteries | |
| KR102325749B1 (en) | Negative electrode material for rechargeable lithium battery, method for manufacturing the same, and rechargeable lithium battery including the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 23795490 Country of ref document: EP Kind code of ref document: A1 |