CN112349900A - Negative pole piece and lithium ion battery containing same - Google Patents
Negative pole piece and lithium ion battery containing same Download PDFInfo
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- CN112349900A CN112349900A CN201910727505.0A CN201910727505A CN112349900A CN 112349900 A CN112349900 A CN 112349900A CN 201910727505 A CN201910727505 A CN 201910727505A CN 112349900 A CN112349900 A CN 112349900A
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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- H01M10/00—Secondary cells; Manufacture thereof
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- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- 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
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- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
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Abstract
The invention provides a negative pole piece and a lithium ion battery containing the same, wherein the negative active material of the negative pole piece is a mixed material of magnesium-silicon-oxygen composite oxide and graphite, wherein the magnesium-silicon-oxygen composite oxide material is compared with SiOyThe material (y is a number between 0.8 and 1.2) has high first charge efficiency and high compaction density (1.8 g/cm can be reached)3) And the method has the advantages of small cyclic expansion and the like, can reduce the volume change of the negative electrode in the lithium intercalation process to a certain extent, and ensuresThe integrity of the particles and the integrity of the pole piece are improved, the cycle performance of the negative pole piece is improved, and SiO can be effectively solvedyThe high-proportion material-blended negative electrode has the problems of low initial charging efficiency, quick cycle attenuation, large cycle expansion and the like, so that the energy density and the cycle life of the battery are remarkably improved, and the high-proportion material-blended negative electrode is suitable for large-scale commercial production. The lithium ion battery recorded by the invention has the advantages that the energy density is obviously improved, the problem of rapid attenuation in the initial cycle stage is effectively improved, and the service life is longer.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a negative pole piece and a lithium ion battery containing the same.
Background
The traditional Lithium Cobaltate (LCO), Nickel Cobalt Manganese (NCM), Nickel Cobalt Aluminum (NCA) and lithium iron phosphate (LFP) anode materials are far from meeting the increasing energy density requirement, so the development of a new high-energy density anode-cathode system is necessary.
The Si-based negative electrode material has excellent performances of high specific capacity, low cost, easy processing and the like; the Si composite material blended graphite cathode is widely applied to the field of high-energy-density cylindrical and steel shell power batteries, but the application of the Si composite material in high-proportion blending and soft package batteries is limited due to large volume expansion in the Si circulation process, and more manufacturers transfer the research gravity center to Si-based cathode materials.
Disclosure of Invention
The Si-based negative electrode material and the Si-C-based negative electrode material have the advantages of high specific capacity (3400 mAh/g), long cycle life and high first coulombic efficiency, but the problems of repeated generation and damage of an SEI (solid electrolyte interphase) film, accelerated electrolyte consumption, increased internal resistance and the like caused by the fact that effective active substances are separated from a conductive network due to large volume expansion and easy falling of particles in the cycle process are solved, so that the problems of difficulty and heaviness in the practical application of the soft package battery are solved. Relatively, silicon monoxide (SiO)yY is between 0.8 and 1.2), although the specific capacity is lower (1800 mAh/g), the material has the advantages of longer cycle life, small volume expansion and the like, and the material is more in line with the requirements of soft package batteries for negative electrode materials and is more and more favored by soft package battery manufacturers, but SiOyThere are also some problems with the large-scale commercial application of materials: for example: SiO 2yThe material consumes a large amount of active Li in the first charge-discharge process, resulting in high contentIrreversible capacity of (a), resulting in low coulombic efficiency for the first cycle (b)<75%), it is not effective to increase the energy density of the whole battery although by applying SiOyThe first coulombic efficiency can be improved to a certain extent by modification (carbon coating, adjustment of Si: O ratio and the like), but the graphite negative electrode level (C) cannot be achieved yet<<93%), the improvement of the energy density of the whole battery in actual use is still limited, and therefore, the limitation of SiO is realizedyThe application of materials and a great obstacle of the process of improving the energy density in the lithium battery industry.
Among many high energy density positive electrode materials, lithium cobaltate positive electrode is not the highest in reversible specific capacity, but is the best positive electrode choice for consumer electronics due to its advantages of high compaction density, high cycle voltage, and the like. Using lithium cobaltate anode to match with SiOyIn the process of first charge and discharge of the battery formed by the mixed cathode, only a small amount of active lithium cannot be inserted back due to the high first charge and discharge efficiency of the lithium cobaltate material, and a large amount of active lithium is consumed at the cathode without a method for participating in the subsequent cycle process, so that the matched SiO is matchedyCompared with the lithium cobaltate material matched with the traditional pure graphite, the actual reversible capacity of the lithium cobaltate material of the mixed cathode is greatly reduced. Meanwhile, because of SiOyIn the process of lithium intercalation, the volume change of the material is large, the thickness change of a pole piece is large in the first charge-discharge process, and the conductive network and the bonding strength of the negative active material are obviously reduced.
In order to overcome the defects of the prior art, the invention aims to provide a negative pole piece and a lithium ion battery containing the same, wherein the negative pole piece uses a mixture of magnesium-silica composite oxide and graphite as a negative active material, the use of the negative active material can reduce the generation of irreversible lithium silicate in the use process of the battery, the consumption of the negative pole on active lithium in the first charge-discharge process is obviously reduced, the first charge-discharge coulombic efficiency of the whole battery is further improved, and simultaneously, the single SiO can be improvedyThe problems of large capacity attenuation, poor cycle performance and the like in the initial cycle period of the cathode material are solved, so that the energy density of the full battery is greatly improved, and the service life of the battery is prolonged.
The purpose of the invention is realized by the following technical scheme:
a negative pole piece comprises a negative pole current collector and negative pole slurry, wherein the negative pole slurry is coated on the negative pole current collector and comprises a negative pole active material, a negative pole binder, a negative pole dispersing agent and a negative pole conductive agent, and the negative pole active material is a mixture of magnesium-silicon-oxygen composite oxide and graphite;
the magnesium-silicon-oxygen composite oxide is Mg2SiO4、Mg3Si3O7、MgSi2O5And MgSiO3One or a combination of more of (a) and SiOyThe complex of (a); wherein y is a number between 0.8 and 1.2.
Further, D of the magnesium-silicon-oxygen composite oxide50And 1-15 μm, the magnesium silicon oxide composite oxide can be prepared by methods known in the art, or can be obtained commercially.
Further, the SiOyIs Si and SiO2The nanoscale composite of (1).
Further, the magnesium-silicon-oxygen composite oxide accounts for 1-55 wt% of the negative active material, preferably 1-40 wt%; for example, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%.
Further, the graphite accounts for 45-99 wt% of the negative active material, preferably 60-99 wt%; for example 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%.
Further, the graphite is selected from natural graphite or artificial graphite.
Further, the negative active material accounts for 90-98 wt% of the solid content of the negative slurry; for example 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%.
Further, the negative electrode binder accounts for 0.1-10 wt% of the solid content of the negative electrode slurry; for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%.
Further, the negative electrode conductive agent accounts for 0.1-2.0 wt% of the solid content of the negative electrode slurry; for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%.
Further, the negative dispersing agent accounts for 0.1-10 wt% of the solid content of the negative slurry; for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%.
Further, the negative electrode conductive agent is selected from one or a combination of more of conductive carbon black, carbon fiber, activated carbon, acetylene black, graphene, super P and carbon nanotubes. Wherein the carbon nanotubes comprise single-walled carbon nanotubes and multi-walled carbon nanotubes.
Further, the negative adhesive is selected from one or a combination of more of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyurethane, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, alginic acid and sodium alginate.
Further, the negative dispersing agent is one or a combination of more of CMC-Na, CMC-Li and PVP.
Further, the negative current collector is a copper foil or a porous copper foil.
The invention also provides a preparation method of the negative pole piece, which comprises the following steps:
step 1: mixing the negative active material, the negative binder, the negative conductive agent and the negative dispersing agent according to the proportion to prepare negative slurry;
step 2: and coating the negative electrode slurry on the surface of a negative electrode current collector, and drying and rolling to obtain a negative electrode plate.
Further, the mixing in the step 1 is, for example, stirring at 20-45 ℃ for 6-18 h.
Further, the thickness of the negative electrode slurry coated on the negative electrode current collector in the step 2 is 20-150 μm.
The invention also provides a lithium ion battery which comprises the negative pole piece.
Furthermore, the lithium ion battery also comprises a positive pole piece, a diaphragm, electrolyte and an aluminum-plastic film.
Furthermore, the area of the negative pole piece is larger than that of the positive pole piece.
Further, the positive pole piece contains a positive active material, and the positive active material is selected from one or a combination of more of lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium iron silicate, lithium cobaltate, a nickel-cobalt-manganese ternary material, a nickel-manganese/cobalt-manganese/nickel-cobalt binary raw material, lithium manganate and a lithium-rich manganese-based material.
Further, the diaphragm is polyethylene polymer, polypropylene polymer or non-woven fabric.
Further, the electrolyte is a non-aqueous electrolyte, the non-aqueous electrolyte comprises a carbonate solvent and a lithium salt, the carbonate solvent is selected from one or a combination of several of Ethylene Carbonate (EC), Propylene Carbonate (PC), diethyl carbonate (DEC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC) and Ethyl Methyl Carbonate (EMC), and the lithium salt is selected from LiPF6、LiBF4、LiSbF6、LiClO4、LiCF3SO3、LiAlO4、LiAlCl4、Li(CF3SO2)2N, LiBOB and LiDFOB.
The invention has the beneficial effects that:
the invention provides a negative pole piece and a lithium ion battery containing the same, wherein the negative active material of the negative pole piece is a mixed material of magnesium-silicon-oxygen composite oxide and graphite, wherein the magnesium-silicon-oxygen composite oxide material is compared with SiOyThe material (y is a number between 0.8 and 1.2) has high first charge efficiency and high compaction density (1.8 g/cm can be reached)3) The lithium-ion battery has the advantages of small cyclic expansion and the like, can reduce the volume change of the negative electrode in the lithium-embedding process to a certain extent, ensures the integrity of particles and the integrity of a pole piece, further improves the cycle performance of the negative electrode pole piece, and can effectively solve the problem of SiOyThe high-proportion material-blended negative electrode has the problems of low initial charging efficiency, quick cycle attenuation, large cycle expansion and the like, thereby remarkably improving the energy density and the cycle life of the battery, and being suitable for large-scale commercializationAnd (5) industrial production.
The lithium ion battery recorded by the invention has the advantages that the energy density is obviously improved, the problem of rapid attenuation in the initial cycle stage is effectively improved, and the service life is longer.
Detailed Description
The preparation method of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
Example 1
(1) Preparation of negative pole piece
The negative pole piece comprises a negative pole current collector and negative pole slurry, wherein the negative pole slurry is coated on the negative pole current collector and comprises a negative pole active material, a negative pole binder, a negative pole conductive agent and a negative pole dispersing agent, the negative pole active material is a mixture of magnesium-silicon-oxygen composite oxide (the particle size D50 is 8 mu m) and graphite, the mass ratio of the magnesium-silicon-oxygen composite oxide to the graphite is 15:85, and the magnesium-silicon-oxygen composite oxide is SiO1.1And MgSi2O5The SiO1.1Is silicon and SiO2The MgSi of2O5Obtained for commercial purchase. The negative electrode dispersing agent is sodium carboxymethylcellulose (CMC-Na), the negative electrode adhesive is Styrene Butadiene Rubber (SBR), water is a solvent, the negative electrode conductive agent is Super P (SP) and single-walled carbon nanotubes (SWCNTs), and the negative electrode active material: CMC-Na: SBR: SP: the mass ratio of SWCNTs is 96:1.5:1.5:0.9:0.1, and the negative current collector is copper foil or porous copper foil.
The preparation method of the negative pole piece comprises the following steps:
the method comprises the following steps: adding the negative electrode active material, the negative electrode binder, the negative electrode dispersant and the negative electrode conductive agent in the proportion into water, and stirring for 18 hours at 20 ℃ to prepare negative electrode slurry with the solid content of 35-50 wt%;
step two: and coating the negative electrode slurry on the surface of a negative current collector with the thickness of 90 mu m, and drying and rolling to obtain the negative electrode piece.
(2) Preparation of positive pole piece
The positive pole piece comprises a positive active material, a positive active material 4.45V lithium cobaltate positive electrode (LiCoO)2) Polyvinylidene fluoride (PVDF) as a binder, N-methylpyrrolidone (NMP) as a solvent, sp (super p) and Carbon Nanotubes (CNT) as a composite conductive agent, the positive electrode active material: PVDF: SP: the mass ratio of the CNTs is 96:2:1.5:0.5, and the positive pole piece is prepared through stirring, coating, rolling, slitting and sheet making.
(3) Preparation of the Battery
The diaphragm is a polyethylene diaphragm, the electrolyte is a non-aqueous electrolyte, the non-aqueous electrolyte comprises a carbonate solvent and a lithium salt, the carbonate solvent is selected from Ethylene Carbonate (EC), and the lithium salt is LiPF6。
The size of the negative pole piece is larger than that of the positive pole piece, and the reversible capacity of the negative pole per unit area is 6% higher than that of the positive pole.
And (3) laminating and assembling the prepared positive electrode and the prepared negative electrode, welding a tab, packaging an aluminum-plastic film, sealing the top and the side, baking moisture in vacuum, injecting liquid and standing after the moisture reaches the standard, forming, vacuumizing for two times after forming, and sorting.
The performance parameters of the prepared battery are as follows:
under the condition of charging and discharging at 25 ℃ and 0.2C, the sorting energy density of the battery can reach 850Wh/L, and the capacity retention rate is 81.3 percent after the battery is cycled for 600 times at 0.5C.
The first charge-discharge efficiency of the negative active material (mixture of magnesium-silicon-oxygen composite oxide and graphite) is 92%, and the reversible gram capacity is 500 mAh/g; the first charge-discharge efficiency of the positive electrode active material was 95%.
Comparative example 1
The other steps are the same as example 1, and the difference is only that (1) the negative electrode activity in the preparation of the negative electrode pieceThe material is SiO1.1And graphite, said SiO1.1And graphite in a mass ratio of 15: 85.
The performance parameters of the prepared battery are as follows:
under the condition of charging and discharging at 25 ℃ and 0.2C, the sorting energy density of the battery is only 750Wh/L, and the capacity retention rate is 76.3 percent after 50 times of 0.5C circulation.
Negative electrode active material (SiO)1.1And graphite) has a first charge-discharge efficiency of 88% and a reversible gram capacity of 500 mAh/g; the first charge-discharge efficiency of the positive electrode active material was 95%.
Example 2
(1) Preparation of negative pole piece
The negative pole piece comprises a negative pole current collector and negative pole slurry, wherein the negative pole slurry is coated on the negative pole current collector and comprises a negative pole active material, a negative pole binder, a negative pole conductive agent and a negative pole dispersing agent, the negative pole active material is a mixture of magnesium-silicon-oxygen composite oxide and graphite, the mass ratio of the magnesium-silicon-oxygen composite oxide to the graphite is 3:7, and the magnesium-silicon-oxygen composite oxide is SiO1.1、MgSiO3And MgSi2O5The SiO1.1Is silicon and SiO2The MgSiO nano-scale compound of3And MgSi2O5Obtained for commercial purchase. The negative electrode dispersing agent is hydroxymethyl cellulose lithium (CMC-Li), the negative electrode adhesive is Styrene Butadiene Rubber (SBR), water is a solvent, the negative electrode conductive agent is Super P (SP) and single-walled carbon nanotubes (SWCNTs), and the negative electrode active material: CMC-Na: SBR: SP: the mass ratio of SWCNTs is 95:1.5:2:1.3:0.2, and the negative current collector is copper foil or porous copper foil.
The preparation method of the negative pole piece comprises the following steps:
the method comprises the following steps: adding the negative electrode active material, the negative electrode binder, the negative electrode dispersant and the negative electrode conductive agent in the proportion into water, and stirring for 18 hours at 20 ℃ to prepare negative electrode slurry with the solid content of 35-50 wt%;
step two: and coating the negative electrode slurry on the surface of a negative current collector with the thickness of 90 mu m, and drying and rolling to obtain the negative electrode piece.
(2) Preparation of positive pole piece
The positive pole piece comprises a positive active material and a positive active material ternary material LiNi0.8Co0.1Mn0.1O2Polyvinylidene fluoride (PVDF) as a binder, N-methylpyrrolidone (NMP) as a solvent, sp (super p) and Carbon Nanotubes (CNT) as a composite conductive agent, the positive electrode active material: PVDF: SP: the mass ratio of the CNTs is 96:2:1.5:0.5, and the positive pole piece is prepared through stirring, coating, rolling, slitting and sheet making.
(3) Preparation of the Battery
The diaphragm is a polyethylene diaphragm, the electrolyte is a non-aqueous electrolyte, the non-aqueous electrolyte comprises a carbonate solvent and a lithium salt, the carbonate solvent is selected from Ethylene Carbonate (EC), and the lithium salt is LiPF6。
The size of the negative pole piece is larger than that of the positive pole piece, and the reversible capacity of the negative pole per unit area is 13% higher than that of the positive pole.
And (3) laminating and assembling the prepared positive electrode and the prepared negative electrode, welding a tab, packaging an aluminum-plastic film, sealing the top and the side, baking moisture in vacuum, injecting liquid and standing after the moisture reaches the standard, forming, vacuumizing for two times after forming, and sorting.
The performance parameters of the prepared battery are as follows:
under the condition of charging and discharging at 25 ℃ and 0.2C, the sorting energy density of the battery can reach 310Wh/L, and the capacity retention rate is 82.6% after the battery is cycled for 300 times at 0.5C.
The first charge-discharge efficiency of the negative active material (the mixture of the magnesium-silicon-oxygen composite oxide and the graphite) is 88%, and the reversible gram capacity is 700 mAh/g; the first charge-discharge efficiency of the positive electrode active material was 89%.
Comparative example 2
The other steps are the same as the example 2, and the difference is only that (1) the negative active material in the preparation of the negative pole piece is SiO1.1And graphite, said SiO1.1And graphite in a mass ratio of 3: 7.
The performance parameters of the prepared battery are as follows:
under the condition of charging and discharging at 25 ℃ and 0.2C, the sorting energy density of the battery is only 290Wh/L, and the capacity retention rate is 70.5 percent after 50 times of 0.5C circulation.
Negative electrode active material (SiO)1.1And graphite) has a first charge-discharge efficiency of 75% and a reversible gram capacity of 700 mAh/g; the first charge-discharge efficiency of the positive electrode active material was 89%.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A negative pole piece comprises a negative pole current collector and negative pole slurry, wherein the negative pole slurry is coated on the negative pole current collector and comprises a negative pole active material, a negative pole binder, a negative pole dispersing agent and a negative pole conductive agent, and the negative pole active material is a mixture of magnesium-silicon-oxygen composite oxide and graphite;
the magnesium-silicon-oxygen composite oxide is Mg2SiO4、Mg3Si3O7、MgSi2O5And MgSiO3One or a combination of more of (a) and SiOyThe complex of (a); wherein y is a number between 0.8 and 1.2.
2. The negative electrode tab of claim 1, wherein D of the magnesium silicon oxygen composite oxide50Is 1-15 μm.
Preferably, the SiOyIs Si and SiO2The nanoscale composite of (1).
3. The negative electrode tab according to claim 1 or 2, wherein the magnesium-silica composite oxide accounts for 1 to 55 wt%, preferably 1 to 40 wt%, of the negative electrode active material.
Preferably, the graphite accounts for 45 to 99 wt%, preferably 60 to 99 wt% of the negative active material.
4. The negative electrode tab of any one of claims 1-3, wherein the negative active material comprises 90-98 wt% of the solid content of the negative paste.
Preferably, the negative electrode binder accounts for 0.1-10 wt% of the solid content of the negative electrode slurry.
Preferably, the negative electrode conductive agent accounts for 0.1-2.0 wt% of the solid content of the negative electrode slurry.
Preferably, the negative electrode dispersant accounts for 0.1-10 wt% of the solid content of the negative electrode slurry.
5. The negative pole piece of any one of claims 1 to 4, wherein the negative conductive agent is selected from one or a combination of more of conductive carbon black, carbon fiber, activated carbon, acetylene black, graphene, super P and carbon nanotubes; wherein the carbon nanotubes comprise single-walled carbon nanotubes and multi-walled carbon nanotubes.
Preferably, the negative adhesive is selected from one or a combination of more of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyurethane, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, alginic acid and sodium alginate.
Preferably, the negative dispersing agent is one or a combination of more of CMC-Na, CMC-Li and PVP.
Preferably, the negative electrode current collector is a copper foil or a porous copper foil.
6. The method for preparing the negative electrode plate of any one of claims 1 to 5, comprising the steps of:
step 1: mixing the negative active material, the negative binder, the negative conductive agent and the negative dispersing agent according to the proportion to prepare negative slurry;
step 2: and coating the negative electrode slurry on the surface of a negative electrode current collector, and drying and rolling to obtain a negative electrode plate.
7. The preparation method according to claim 6, wherein the mixing in step 1 is performed by stirring at 20-45 ℃ for 6-18 h.
Preferably, the thickness of the negative electrode slurry coated on the negative electrode current collector in step 2 is 20-150 μm.
8. A lithium ion battery comprising the negative electrode sheet according to any one of claims 1 to 5.
9. The lithium ion battery of claim 8, wherein the lithium ion battery further comprises a positive electrode sheet, a separator, an electrolyte, and an aluminum plastic film.
Preferably, the area of the negative pole piece is larger than that of the positive pole piece.
Preferably, the positive electrode piece contains a positive active material, and the positive active material is selected from one or a combination of several of lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium iron silicate, lithium cobaltate, a nickel-cobalt-manganese ternary material, a nickel-manganese/cobalt-manganese/nickel-cobalt binary raw material, lithium manganate and a lithium-rich manganese-based material.
Preferably, the separator is a polyethylene polymer, a polypropylene polymer, or a nonwoven fabric.
10. The lithium ion battery of claim 9, wherein the electrolyte is a non-aqueous electrolyte comprising a carbonate solvent selected from one or a combination of Ethylene Carbonate (EC), Propylene Carbonate (PC), diethyl carbonate (DEC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC) and Ethyl Methyl Carbonate (EMC), and a lithium salt selected from LiPF6、LiBF4、LiSbF6、LiClO4、LiCF3SO3、LiAlO4、LiAlCl4、Li(CF3SO2)2N, LiBOB and LiDFOB.
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| CN201910727505.0A CN112349900A (en) | 2019-08-07 | 2019-08-07 | Negative pole piece and lithium ion battery containing same |
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| CN113013390A (en) * | 2021-02-20 | 2021-06-22 | 珠海冠宇电池股份有限公司 | Negative plate and lithium ion battery |
| CN113488636A (en) * | 2021-06-18 | 2021-10-08 | 东莞塔菲尔新能源科技有限公司 | Composite negative electrode material, negative plate and lithium ion battery |
| CN113764651A (en) * | 2021-08-24 | 2021-12-07 | 复旦大学 | High-capacity lithium ion battery negative electrode active material, negative electrode plate and lithium ion battery |
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| CN113013390A (en) * | 2021-02-20 | 2021-06-22 | 珠海冠宇电池股份有限公司 | Negative plate and lithium ion battery |
| CN113488636A (en) * | 2021-06-18 | 2021-10-08 | 东莞塔菲尔新能源科技有限公司 | Composite negative electrode material, negative plate and lithium ion battery |
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