CN116632244A - Negative electrode slurry, preparation method, negative electrode plate and lithium ion battery - Google Patents
Negative electrode slurry, preparation method, negative electrode plate and lithium ion battery Download PDFInfo
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- CN116632244A CN116632244A CN202310792992.5A CN202310792992A CN116632244A CN 116632244 A CN116632244 A CN 116632244A CN 202310792992 A CN202310792992 A CN 202310792992A CN 116632244 A CN116632244 A CN 116632244A
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- 239000011267 electrode slurry Substances 0.000 title claims abstract description 42
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 16
- 239000000654 additive Substances 0.000 claims abstract description 32
- 230000000996 additive effect Effects 0.000 claims abstract description 32
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 7
- 239000001257 hydrogen Substances 0.000 claims abstract description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 6
- 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 claims abstract description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 4
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims abstract description 4
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 4
- 239000011591 potassium Substances 0.000 claims abstract description 4
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 4
- 239000011734 sodium Substances 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 20
- 239000002002 slurry Substances 0.000 claims description 17
- 239000011230 binding agent Substances 0.000 claims description 15
- 239000006258 conductive agent Substances 0.000 claims description 13
- 239000007787 solid Substances 0.000 claims description 13
- 239000011268 mixed slurry Substances 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 239000002904 solvent Substances 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 9
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- 239000006256 anode slurry Substances 0.000 claims description 6
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 239000006245 Carbon black Super-P Substances 0.000 claims description 4
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 4
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims description 3
- LLYXJBROWQDVMI-UHFFFAOYSA-N 2-chloro-4-nitrotoluene Chemical compound CC1=CC=C([N+]([O-])=O)C=C1Cl LLYXJBROWQDVMI-UHFFFAOYSA-N 0.000 claims description 3
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 3
- 239000006230 acetylene black Substances 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 229910021385 hard carbon Inorganic materials 0.000 claims description 3
- 239000004005 microsphere Substances 0.000 claims description 3
- 229910021382 natural graphite Inorganic materials 0.000 claims description 3
- 239000004584 polyacrylic acid Substances 0.000 claims description 3
- 239000000661 sodium alginate Substances 0.000 claims description 3
- 235000010413 sodium alginate Nutrition 0.000 claims description 3
- 229940005550 sodium alginate Drugs 0.000 claims description 3
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 3
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 3
- 229910021384 soft carbon Inorganic materials 0.000 claims description 3
- 230000001276 controlling effect Effects 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 239000006183 anode active material Substances 0.000 claims 1
- 239000007773 negative electrode material Substances 0.000 claims 1
- 239000003792 electrolyte Substances 0.000 abstract description 19
- 238000000576 coating method Methods 0.000 abstract description 10
- 206010042674 Swelling Diseases 0.000 abstract description 9
- 230000008961 swelling Effects 0.000 abstract description 9
- 238000005336 cracking Methods 0.000 abstract description 7
- 230000008901 benefit Effects 0.000 abstract description 6
- 238000011065 in-situ storage Methods 0.000 abstract description 6
- 230000000052 comparative effect Effects 0.000 description 20
- 229920006318 anionic polymer Polymers 0.000 description 15
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 11
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 11
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 9
- 150000001875 compounds Chemical class 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000002174 Styrene-butadiene Substances 0.000 description 5
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 239000003292 glue Substances 0.000 description 5
- 238000001764 infiltration Methods 0.000 description 5
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 4
- 230000002209 hydrophobic effect Effects 0.000 description 4
- 230000003993 interaction Effects 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000009736 wetting Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical group O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229920006184 cellulose methylcellulose Polymers 0.000 description 2
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical group FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 229920001909 styrene-acrylic polymer Polymers 0.000 description 2
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical group FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000002313 adhesive film Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000007600 charging Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000010280 constant potential charging Methods 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000004807 desolvation Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- CWAFVXWRGIEBPL-UHFFFAOYSA-N ethoxysilane Chemical compound CCO[SiH3] CWAFVXWRGIEBPL-UHFFFAOYSA-N 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000005213 imbibition Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- -1 perfluorocarbon chain compound Chemical class 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- 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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- 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
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—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
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
- H01M4/623—Binders being polymers fluorinated polymers
-
- 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
-
- 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
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
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- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application belongs to the field of lithium batteries, and particularly relates to negative electrode slurry, a preparation method thereof, a negative electrode plate and a lithium ion battery. The negative electrode slurry comprises a negative electrode slurry additive, and the structure of the negative electrode slurry additive is shown as a formula (I);wherein M is at least one of hydrogen, lithium, sodium or potassium; n is more than or equal to 4 and less than or equal to 14, and is an integer. The in-situ high-wettability negative plate prepared by the negative electrode slurry provided by the application has the advantages of simple preparation process, no influence on the conductivity of electrolyte, and no need of early stageThe pretreatment can avoid the battery swelling risk caused by the high swelling of the negative electrode plate, prevent the negative electrode plate from cracking to a certain extent in the coating process, and has the characteristics of high binding force and high conductivity, thereby improving the rate capability of the battery and having good application prospect.
Description
Technical Field
The application belongs to the field of lithium batteries, and particularly relates to negative electrode slurry, a preparation method thereof, a negative electrode plate and a lithium ion battery.
Background
In recent years, with the strong support of policies, lithium ion batteries have entered a new strategic development key period. With further increases in coating and compaction, rapid infiltration of the pole piece by the electrolyte becomes a significant challenge. Whether the wettability of the interface of the negative electrode well influences the formation quality of an SEI film or not, mass transfer impedance at the interface is increased due to poor infiltration of the negative electrode sheet, desolvation process is slow, dynamic behavior of lithium ion intercalation into the negative electrode is limited, and therefore lithium salt deposition is induced at the interface, and the interface state of the negative electrode is deteriorated. Over time, as charge and discharge proceeds, the electrolyte side reaction at the negative electrode interface is aggravated due to poor wettability, the SEI film is continuously thickened, lithium ion transmission is hindered, and finally the rate performance is deteriorated, the capacity exertion is affected, and circulating water is caused.
In addition, the high surface tension of the negative electrode plate in the coating and drying process causes the electrode plate to crack, so that the resistance of the electrode plate is increased, and the multiplying power and the cycle performance are also deteriorated. In addition, the traditional method for improving the cracking and poor adhesion of the pole piece is to increase the amount of the adhesive in the pole piece, but the method inevitably causes the increase of the resistance of the pole piece, and finally leads to the reduction of the rate performance and the deterioration of the electrical performance of the battery.
Therefore, a method capable of improving the wettability of the negative electrode interface in situ, ensuring the bonding force of the pole piece, preventing the pole piece from cracking, and simultaneously not affecting the resistance of the pole piece and the multiplying power performance of the battery is found to be important for improving the comprehensive electrical performance of the lithium ion battery.
At present, the means for improving the wettability of the negative electrode plate to the electrolyte mainly comprises the steps of introducing a impregnating compound into the electrolyte formula and adding an additive in the process of homogenizing the negative electrode. CN114583276a discloses a high-wettability electrolyte formula, the selected impregnating compound is vinyl tri (2, 2-trifluoro) ethoxysilane, so that the wettability of the electrolyte to the electrode plate is improved, but the addition of a small amount of the impregnating compound affects the conductivity of the electrolyte, and the improvement of the wettability is ineffective if the addition amount is too small. CN112500542a discloses a water-soluble cross-linking additive of styrene-acrylic copolymer-b-PEO-b-styrene-acrylic copolymer block copolymer for negative plate, which improves the affinity of the negative plate with electrolyte and improves the liquid retention of the negative plate by means of network structure and hydrophilic group in the polymer, but the preparation process of the polymer is complex, and the cross-linking agent swells after imbibition, thus increasing the swelling of the negative plate in the later period of circulation and the risk of battery swelling. CN114388792a discloses an acrylic resin and its derivative additive for negative electrode sheet, which can form anionic polymer emulsion when preparing negative electrode slurry, and uses particle adhesive film to make high swelling in electrolyte, so as to increase wettability of negative electrode sheet.
Disclosure of Invention
The application aims to overcome the defects in the prior art and provides negative electrode slurry, a preparation method, a negative electrode plate and a lithium ion battery.
In order to achieve the above purpose, the application adopts the following technical scheme:
a negative electrode slurry additive, the structure of which is shown as a formula (I);
wherein M is at least one of hydrogen, lithium, sodium or potassium; n is more than or equal to 4 and less than or equal to 14, and is an integer.
Preferably, the structure is as shown in formula (I I);
the application also comprises a negative electrode slurry, which comprises the negative electrode slurry additive; the negative electrode slurry additive is 0.05% -0.2%, preferably 0.1% -0.15%, more preferably 0.15% of the total dry weight of the negative electrode slurry preparation material.
The negative electrode slurry preparation material comprises a negative electrode active main material, a conductive agent, a binder and a negative electrode slurry additive; the dry weight of the negative electrode active main material is 93% -98%, the dry weight of the conductive agent is 0.5% -5% and the dry weight of the binder is 0.5% -3% based on 100% of the total dry weight of the negative electrode slurry preparation material.
The negative electrode active main material is a carbon material and comprises at least one of natural graphite, artificial graphite, mesophase carbon microspheres, hard carbon, soft carbon and the like.
The conductive agent is at least one of Super-P, ECP, CNT, graphene, acetylene black and the like.
The binder comprises at least one of styrene-butadiene rubber, sodium carboxymethyl cellulose, sodium alginate and polyacrylic acid.
The application also comprises a preparation method of the negative electrode slurry, which comprises the following steps:
(1) Mixing the cathode active main material and the conductive agent according to the component amounts;
(2) Adding a binder into the mixed slurry obtained in the step (1), adding a solvent, fully stirring, and performing first-time solid content adjustment;
(3) Adding the binder into the mixed slurry obtained in the step (2) again, adding the solvent, fully stirring, and carrying out secondary solid content adjustment;
(4) Adding the binder into the mixed slurry obtained in the step (3) again, adding the solvent, fully stirring, and carrying out third solid content adjustment;
then, regulating and controlling the addition amount of the solvent until the viscosity of the slurry reaches the requirement;
the negative electrode slurry additive is added in any one step or multiple steps of (2), (3) and (4).
Preferably, the solid content of the final slurry is 40% -60% and the viscosity is 3000+ -200 cp.
The application also comprises a lithium ion battery, which comprises a negative plate; the negative electrode plate is obtained by coating the negative electrode slurry on the surface of a negative electrode current collector.
Compared with the prior art, the application has the beneficial effects that:
the anionic polymer additive provided by the application has the following advantages: 1) The bond energy of the C-F bond is larger, the electrochemical stability is stronger, and no additional side reaction occurs in the charge and discharge process of the battery; 2) The slurry state during homogenate is synergistically improved by virtue of the hydrophobic effect of the perfluorocarbon chain and the hydrophilicity of the carboxyl group, so that the in-situ high-infiltration negative plate is obtained; 3) The carboxyl group can generate hydrogen bond interaction force with CMC molecules, and the fluorocarbon chain can be intertwined with the butadiene conjugated chain of the SBR molecules, so that the carboxyl group can be stably suspended in mixed slurry during homogenate, the binding force of a negative plate is improved under the condition that the dosage of an integral binder is not increased, and the damage to the rate performance of a battery due to the increase of SBR and CMC is avoided; 4) The lone pair electron cloud of the carbonyl oxygen atoms can promote lithium ion migration, improve the conductivity of the pole piece and further improve the rate capability; 5) At extremely low addition amount, the interfacial tension between phases can be obviously reduced, and the cracking phenomenon of the negative electrode sheet during coating is relieved.
The in-situ high-infiltration negative plate provided by the application has the advantages that the preparation process is simple, the conductivity of electrolyte is not affected, the pre-treatment is not needed, the battery swelling risk caused by the high swelling of the negative plate is avoided, the cracking of the negative plate in the coating process can be prevented to a certain extent, the high-cohesive-force and high-conductivity characteristics are realized, the rate performance of the battery is further improved, and the application prospect is good.
Drawings
FIG. 1 is a constant flow charge ratio chart of an example of the present application and a comparative example;
fig. 2 is a cycle performance test chart of the embodiment of the present application and the comparative example.
Detailed Description
In order to make the technical scheme of the present application better understood by those skilled in the art, the present application will be described in further detail with reference to the following examples, wherein the percentages in the present application are mass percentages unless otherwise indicated.
The negative electrode slurry additive used in the application is an anionic polymer additive, and is shown as a formula (II) and a molecular formula C unless otherwise specified 7 HF 13 O 2 ；
Example 1
The manufacturing method of the negative plate and the lithium ion battery comprises the following steps:
(1) Preparing a negative plate preparation material, wherein the dry weight ratio (wt%) of artificial graphite, conductive carbon black Super P, carboxymethyl cellulose CMC and styrene butadiene rubber SBR is 96.3:1.0:1.2:1.5.
(2) Preparing CMC glue solution, wherein the CMC solid content is 1.5%, and the solvent is deionized water.
(3) Mixing artificial graphite and Super P according to a set proportion, adding 60% (mass fraction of total feeding amount of CMC glue) CMC glue and deionized water after stirring at low speed, fully mixing, and performing first solid content debugging.
(4) Adding 20% CMC glue solution and deionized water into the mixed slurry again, adding anionic polymer additive accounting for 0.05% of the total dry weight of the negative plate preparation material, fully stirring, and performing secondary solid content adjustment.
(5) Adding 20% CMC glue solution and deionized water into the mixed slurry obtained in the step (4) again, and carrying out third solid content adjustment after full mixing; then, adjusting the viscosity of the slurry to 3000cp by adjusting the addition amount of deionized water; adding SBR into the obtained mixed slurry again, wherein the solid content of the final slurry is 50 percent (40-60 percent can be needed); and (5) after stirring at a low speed, vacuumizing, and sieving with a 100-mesh sieve for discharging.
(6) And coating the obtained negative electrode slurry on the surface of a negative electrode current collector, rolling and tabletting, assembling with a lithium iron phosphate positive plate and a diaphragm, and injecting liquid to obtain the lithium ion battery.
The application also relates to a preparation method of the anode slurry additive (the structure is shown as a formula (I), and the structural formula is CF 3 (CF 2 ) n COOM) for testing;
m is hydrogen, lithium, sodium or potassium; the compounds having a value of 4.ltoreq.n.ltoreq.14, for example, n of 4, 8, 10, 12, are exemplified as preferred examples because they each contain an anionic carboxyl group to improve the affinity of the electrolyte and contain hydrophobic effects of fluorides having different degrees of polymerization, and thus can each improve the slurry state to a different extent to obtain an in-situ high-wettability negative electrode sheet, and among them, the effect of the compound of formula (II) is particularly preferable.
Example 2
The only difference from example 1 is that 0.1% of anionic polymer additive is added in step (4).
Example 3
The only difference from example 1 is that 0.15% of the anionic polymer additive is added in step (4).
Example 4
The only difference from example 1 is that 0.2% of the anionic polymer additive is added in step (4).
Comparative example 1
The only difference from example 1 is that no anionic polymer additive is added in step (4).
Comparative example 2
The difference from comparative example 1 is only that the perfluorocarbon chain compound represented by the formula (III) was added in step (4).
The slurries of comparative examples 1 to 2 and examples 1 to 4 and the surface states of the prepared negative electrode sheets were observed, and the surface tension of the slurries and the wettability and adhesion of the negative electrode sheets were tested, and the prepared lithium ion batteries were subjected to electrical property tests.
(1) Liquid absorption test
Preparing the prepared negative plate into a small disc with the diameter of 3cm by using a sampler, weighing and marking as m 0 . Then, the wafer was placed in the electrolyte for 4 hours, taken out and weighed again, and recorded as m 1 The liquid absorption (%) was expressed as (m 1 -m 0 )/m 0 。
(2) Electrical performance testing
Rate charging performance: after constant current charging to 3.65V at 0.2C,0.5C,1.0C and 2.0C, respectively, constant voltage charging to 0.05C, 1C discharge to 2.5V.
Cycle performance at 45 ℃): the charge-discharge circulation system of 1C/1C is adopted, and the voltage range is 2.5V-3.65V.
The slurry state, pole piece surface state and slurry surface tension test results in comparative examples 1-2 and examples 1-4 are shown in table 1, pole piece adhesion, contact angle and liquid absorption test results are shown in table 2, and the electrical property test results are shown in table 3.
TABLE 1
As shown in Table 1, the slurry of comparative example 2 has agglomeration, the surface of the pole piece has large particles, the slurry of the other comparative examples and each example has good fluidity, the surface of the pole piece is flat, the dispersion property of the compound of formula (III) is poor due to the hydrophobic effect of the C-F bond, the slurry is agglomerated, and the pole piece shows large particles after coating. However, the anionic polymer additive can be perfectly matched to the negative electrode slurry system due to the presence of hydrophilic carboxyl groups. Meanwhile, the surfaces of the pole pieces of comparative examples 1 and 2 are microcracked, the surface tension of the slurry is larger, and the surfaces of the pole pieces of each example are not cracked, so that the surface tension of the slurry is smaller, which indicates that the interfacial tension between phases can be obviously reduced by introducing the anionic polymer additive into the negative electrode slurry, and the cracking phenomenon of the pole pieces during coating is reduced.
TABLE 2
As can be seen from table 2, the pole pieces of each example have a larger adhesion force, while the comparative examples have a smaller adhesion force, wherein the adhesion force of comparative example 2 is the smallest, which indicates that the anionic polymer additive can ensure Jiang Nianjie force of the negative pole piece by virtue of the hydrogen bond interaction force between the carboxyl group and CMC, and the intertwining of the fluorocarbon chain and SBR butadiene conjugated chain. Whereas the compound of formula (III) has no advantage in terms of adhesion to comparative example (2) due to lack of hydrogen bonding interaction between carboxyl groups and repulsion with the negative electrode slurry system upon homogenization. In addition, the contact angle of the negative electrode plate in different schemes is tested by adopting commercial electrolyte, and the results show that the contact angle of each comparative example is larger, the liquid absorption rate is smaller, the contact angle of each example is smaller, the liquid absorption rate is larger, the affinity of the electrode plate to the electrolyte can be obviously improved due to the existence of hydrophilic carboxyl groups of the anionic polymer additive, wherein the contact angle of the example 3 is minimum, only 11.32 degrees, the liquid absorption rate is maximum, 28.87 percent is achieved, the optimal addition amount of the anionic polymer additive is 0.15 percent, and the wetting degree of the electrode plate is best improved under the optimal addition amount, thereby being most beneficial to wetting the electrode plate by the electrolyte.
TABLE 3 Table 3
FIG. 1 is a constant flow charge ratio chart of an example of the present application and a comparative example; fig. 2 is a cycle performance test chart of the embodiment of the present application and the comparative example. As seen from table 3, fig. 1 and fig. 2, the constant current charge ratios at different charge rates of the comparative examples were smaller and the capacity retention rates at 1000 cycles at 45 ℃ were lower than those of the respective examples. However, the constant current charge ratio of example 3 was the greatest at different charge rates, and in particular, the constant current charge ratio at 2C charge rate had reached 98.23% which was 0.48% higher than that of comparative example 1. In addition, the capacity retention rate of example 3 at 45℃for circulation reached 88.5%, which is 1.1% higher than that of comparative example 1. In conclusion, the anionic polymer additive has the advantages that due to the existence of the lone pair electron cloud of the carbonyl oxygen atom, the conductivity of the pole piece is improved, the lithium ion migration is promoted, meanwhile, the affinity of the pole piece to electrolyte is improved due to the hydrophobic effect of the perfluorocarbon chain and the hydrophilicity of the carboxyl group, and therefore the best rate performance and high-temperature cycle performance are shown.
Likewise, for different anode slurry preparation materials, for example, the anode active main material is a carbon material including natural graphite, artificial graphite, mesophase carbon microspheres, hard carbon and soft carbon; the conductive agent is Super-P, ECP, CNT, graphene, acetylene black and the like, the binder is styrene-butadiene rubber, sodium carboxymethyl cellulose, sodium alginate, polyacrylic acid and the like, and substances with different proportions are prepared, namely 93%, 95.8% or 98% of the dry weight of the active main material of the negative electrode is calculated by taking the total dry weight of the preparation material of the negative electrode slurry as 100%, 0.5%, 2.7%, 3% or 5% of the dry weight of the conductive agent is obtained after the dry weight of the binder is adjusted, and the dry weight of the conductive agent is 0.5%, 1.5%, 2.6% or 3% of the conductive agent is obtained after the dry weight of the conductive agent is adjusted, and compared with the corresponding comparative examples 1 and 2, namely, the negative electrode slurry is not added with an anionic polymer additive and the compound of the formula (III), the wetting degree of the negative electrode active main material and the electrolyte is improved to different degrees, so that the performance of the battery is improved finally.
The in-situ high-infiltration negative plate provided by the application has the advantages that the preparation process is simple, the conductivity of electrolyte is not affected, the pre-treatment is not needed, the battery swelling risk caused by the high swelling of the negative plate is avoided, the cracking of the negative plate in the coating process can be prevented to a certain extent, the high-cohesive-force and high-conductivity characteristics are realized, the rate performance of the battery is further improved, and the application prospect is good.
The foregoing is merely a preferred embodiment of the present application and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present application, which are intended to be comprehended within the scope of the present application.
Claims (10)
1. The negative electrode slurry is characterized by comprising a negative electrode slurry additive, wherein the structural formula of the negative electrode slurry additive is shown as formula (I);
wherein M is at least one of hydrogen, lithium, sodium or potassium; n is more than or equal to 4 and less than or equal to 14, and is an integer.
2. The anode slurry according to claim 1, wherein the anode slurry additive has a structural formula shown in formula (II);
3. the negative electrode slurry according to claim 1 or 2, characterized in that the negative electrode slurry additive is 0.05-0.2%, preferably 0.1-0.15%, more preferably 0.15% of the total dry weight of the negative electrode slurry preparation material.
4. A negative electrode slurry according to any one of claims 1 to 3, wherein the negative electrode slurry preparation material comprises a negative electrode active main material, a conductive agent, a binder, and a negative electrode slurry additive; the dry weight of the negative electrode active main material is 93% -98%, the dry weight of the conductive agent is 0.5% -5% and the dry weight of the binder is 0.5% -3% based on 100% of the total dry weight of the negative electrode slurry preparation material.
5. The anode slurry according to any one of claims 1 to 4, wherein the anode active material is a carbon material including at least one of natural graphite, artificial graphite, mesophase carbon microspheres, hard carbon, and soft carbon.
6. The anode slurry according to any one of claims 1 to 5, wherein the conductive agent is at least one of Super-P, ECP, CNT, graphene, and acetylene black.
Preferably, the binder comprises at least one of styrene-butadiene rubber, sodium carboxymethyl cellulose, sodium alginate and polyacrylic acid.
7. A method for producing the negative electrode slurry according to any one of claims 1 to 6, comprising the steps of:
(1) Mixing the cathode active main material and the conductive agent according to the component amounts;
(2) Adding part of binder into the mixed slurry obtained in the step (1), adding solvent, fully stirring, and performing first solid content adjustment;
(3) Adding part of binder into the mixed slurry obtained in the step (2), adding solvent, fully stirring, and performing secondary solid content adjustment;
(4) Adding the residual binder into the mixed slurry obtained in the step (3), adding the solvent, fully stirring, and carrying out third solid content adjustment;
then, regulating and controlling the addition amount of the solvent until the viscosity of the slurry reaches the requirement;
the negative electrode slurry additive is added in any one step or multiple steps of (2), (3) and (4).
8. A method of preparing the negative electrode slurry of claim 7, wherein the final slurry has a solids content of 40% -60% and a viscosity of 3000±200cp.
9. A negative electrode sheet comprising a negative electrode current collector and a negative electrode active material layer prepared from the negative electrode slurry according to any one of claims 1 to 6.
10. A lithium ion battery comprising the negative electrode sheet of claim 9.
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| CN117810455A (en) * | 2024-03-01 | 2024-04-02 | 深圳市华明胜科技有限公司 | Graphite negative electrode material with strong cohesiveness and preparation method thereof |
| CN117810455B (en) * | 2024-03-01 | 2024-05-24 | 深圳市华明胜科技有限公司 | Graphite negative electrode material with strong cohesiveness and preparation method thereof |
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| CN117810455A (en) * | 2024-03-01 | 2024-04-02 | 深圳市华明胜科技有限公司 | Graphite negative electrode material with strong cohesiveness and preparation method thereof |
| CN117810455B (en) * | 2024-03-01 | 2024-05-24 | 深圳市华明胜科技有限公司 | Graphite negative electrode material with strong cohesiveness and preparation method thereof |
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