CN116470010A - Thick electrode and preparation method and application thereof - Google Patents
Thick electrode and preparation method and application thereof Download PDFInfo
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- CN116470010A CN116470010A CN202310532835.0A CN202310532835A CN116470010A CN 116470010 A CN116470010 A CN 116470010A CN 202310532835 A CN202310532835 A CN 202310532835A CN 116470010 A CN116470010 A CN 116470010A
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- lithium
- thick electrode
- electrode
- thick
- solvent
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- 238000002360 preparation method Methods 0.000 title abstract description 16
- 239000002904 solvent Substances 0.000 claims abstract description 27
- 239000011268 mixed slurry Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 19
- 239000000853 adhesive Substances 0.000 claims abstract description 16
- 230000001070 adhesive effect Effects 0.000 claims abstract description 16
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 16
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 16
- 239000006258 conductive agent Substances 0.000 claims abstract description 14
- 238000010438 heat treatment Methods 0.000 claims abstract description 11
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 238000001816 cooling Methods 0.000 claims abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052744 lithium Inorganic materials 0.000 claims description 8
- -1 lithium tetrafluoroborate Chemical compound 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 7
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 7
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 6
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 5
- KWOLFJPFCHCOCG-UHFFFAOYSA-N Acetophenone Chemical compound CC(=O)C1=CC=CC=C1 KWOLFJPFCHCOCG-UHFFFAOYSA-N 0.000 claims description 4
- MTZQAGJQAFMTAQ-UHFFFAOYSA-N ethyl benzoate Chemical compound CCOC(=O)C1=CC=CC=C1 MTZQAGJQAFMTAQ-UHFFFAOYSA-N 0.000 claims description 4
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 claims description 3
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 3
- JGFBQFKZKSSODQ-UHFFFAOYSA-N Isothiocyanatocyclopropane Chemical compound S=C=NC1CC1 JGFBQFKZKSSODQ-UHFFFAOYSA-N 0.000 claims description 3
- 239000002033 PVDF binder Substances 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 3
- 239000004952 Polyamide Substances 0.000 claims description 3
- 229920002873 Polyethylenimine Polymers 0.000 claims description 3
- 239000004642 Polyimide Substances 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- PWLNAUNEAKQYLH-UHFFFAOYSA-N butyric acid octyl ester Natural products CCCCCCCCOC(=O)CCC PWLNAUNEAKQYLH-UHFFFAOYSA-N 0.000 claims description 3
- DEUISMFZZMAAOJ-UHFFFAOYSA-N lithium dihydrogen borate oxalic acid Chemical compound B([O-])(O)O.C(C(=O)O)(=O)O.C(C(=O)O)(=O)O.[Li+] DEUISMFZZMAAOJ-UHFFFAOYSA-N 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 claims description 3
- 229910001486 lithium perchlorate Inorganic materials 0.000 claims description 3
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 claims description 3
- UUIQMZJEGPQKFD-UHFFFAOYSA-N n-butyric acid methyl ester Natural products CCCC(=O)OC UUIQMZJEGPQKFD-UHFFFAOYSA-N 0.000 claims description 3
- 229920002647 polyamide Polymers 0.000 claims description 3
- 229920001721 polyimide Polymers 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 229920002125 Sokalan® Polymers 0.000 claims description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 2
- 239000006230 acetylene black Substances 0.000 claims description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 claims description 2
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims description 2
- 238000009835 boiling Methods 0.000 claims description 2
- 239000002134 carbon nanofiber Substances 0.000 claims description 2
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 2
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 2
- 239000006232 furnace black Substances 0.000 claims description 2
- 229910021389 graphene Inorganic materials 0.000 claims description 2
- 239000007770 graphite material Substances 0.000 claims description 2
- 239000010410 layer Substances 0.000 claims description 2
- XKLXIRVJABJBLQ-UHFFFAOYSA-N lithium;2-(trifluoromethyl)-1h-imidazole-4,5-dicarbonitrile Chemical compound [Li].FC(F)(F)C1=NC(C#N)=C(C#N)N1 XKLXIRVJABJBLQ-UHFFFAOYSA-N 0.000 claims description 2
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 239000011572 manganese Substances 0.000 claims description 2
- 239000002048 multi walled nanotube Substances 0.000 claims description 2
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 claims description 2
- 239000002153 silicon-carbon composite material Substances 0.000 claims description 2
- 239000002109 single walled nanotube Substances 0.000 claims description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims 1
- 239000004584 polyacrylic acid Substances 0.000 claims 1
- 239000002356 single layer Substances 0.000 claims 1
- 230000007547 defect Effects 0.000 abstract description 5
- 238000005245 sintering Methods 0.000 abstract description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 4
- 150000002500 ions Chemical class 0.000 abstract description 4
- 238000009776 industrial production Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 9
- 238000000576 coating method Methods 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000011230 binding agent Substances 0.000 description 6
- 239000003792 electrolyte Substances 0.000 description 5
- 239000011888 foil Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 239000011889 copper foil Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000004480 active ingredient Substances 0.000 description 3
- 239000013543 active substance Substances 0.000 description 3
- 238000013329 compounding Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000011267 electrode slurry Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910013872 LiPF Inorganic materials 0.000 description 2
- 101150058243 Lipf gene Proteins 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000007580 dry-mixing Methods 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- 229910015013 LiAsF Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000131 polyvinylidene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012546 transfer 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
- H01M4/139—Processes of manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a thick electrode, a preparation method and application thereof, and relates to the technical field of lithium ion batteries. Specifically, the thick electrode is prepared by the following steps: fully mixing an electrode active component, lithium salt, a conductive agent, an adhesive and a solvent, heating the mixed slurry to 110-180 ℃, compositing the hot mixed slurry with a current collector, and cooling to obtain a thick electrode. The preparation method provided by the invention avoids the defects that the conventional process is easy to crack, has poor bonding capability, cannot realize industrial production and the like when the thick electrode is prepared; the thick electrode provided by the invention has the effect of improving the ion conductivity and the electron conductivity, so that the thick electrode has the effects of improving the charging capacity, improving the multiplying power performance and the like. Meanwhile, the preparation process does not need N-methyl pyrrolidone, does not need a pole piece baking or sintering process, does not have unsafe gas emission, is more environment-friendly and safer, and can be used for mass production.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a thick electrode and a preparation method and application thereof.
Background
The content of active substances in the electrode of the lithium ion battery determines the capacity and the energy density which can be output by the battery, and the design of the thick electrode means that higher energy output can be realized, so that the thick electrode has wide application prospect in the field of lithium batteries. However, the proportion of inactive substances (such as current collectors and diaphragms) in the thick electrode is low, the thickness of the pole piece is increased, the tortuosity of the pole piece is increased, the wettability of the electrolyte is reduced (electrolyte on the surface layer of the electrode is well infiltrated, and more closed holes possibly exist in the pole piece so that the electrolyte cannot infiltrate), finally, the migration path of ions in the thick electrode is increased, or the performance of the main material cannot be exerted, so that the charging capacity of the battery is reduced.
For the preparation of thick electrodes, the following method and process are often used: 1) Conventional wet coating methods: the electrode raw materials are fully mixed in a solvent, then coated on a current collector by using methods such as phase transfer, extrusion and the like, and then dried in an oven section to remove the solvent and obtain a pole piece; however, this method is not easy to dry when the coating thickness is increased, and is easy to crack and peel after drying. 2) Dry mixing method: the electrode raw materials are fully mixed in a dry state, then the adhesive is added, the mixture is fully stirred or ground, the mixed materials are repeatedly rolled by a roller, the adhesive fully spreads and bonds the main materials, and finally the electrode plate with the required thickness is compounded with the current collector. The dry mixing does not have the problem of cracking, but has the defect that when the thickness of the pole piece is increased, the contact of the material and the current collector is not tight, and even the current collector falls off. 3) Other preparation processes such as plasma sintering technology, template method, carbon nanotube array and biomass sintering are suitable for small-batch preparation of thick electrodes, and are not suitable for the existing battery mass production line.
In view of this, the present invention has been made.
Disclosure of Invention
The first object of the present invention is to provide a method for preparing a thick electrode, which solves the defect that the conventional electrode preparation process in the prior art is difficult to adapt to the thick electrode, and simultaneously solves the defect that the electrochemical performance of the thick electrode is limited by ion and electron transfer and rapid capacity degradation due to high thickness and large tortuosity. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:
a method for preparing a thick electrode, comprising the steps of: and fully mixing the electrode active components, lithium salt, a conductive agent, an adhesive and a solvent, heating the mixed slurry to 110-180 ℃, compositing the heated mixed slurry with a current collector, and cooling to obtain the thick electrode.
Preferably, the electrode active component includes at least one of lithium cobaltate, lithium iron phosphate, ternary materials (such as NCM811, NCM622, NCM523, etc.), lithium-rich manganese-based materials, or lithium manganate; alternatively, the electrode active component includes at least one of a graphite material, amorphous carbon, a titanium oxide, or a silicon carbon composite.
Preferably, the lithium salt lithium tetrafluoroborate (LiBF 4 ) Lithium bissulfonylimide (LiSSI), lithium difluorophosphate (LiPF) 2 O 2 ) Lithium bis (trifluoromethane) sulfonimide (LiTFSI), lithium hexafluorophosphate (LiPF) 6 ) Lithium dioxalate borate (LiDFOB), lithium 4, 5-dicyano-trifluoromethyl imidazole (LiDTI), lithium perchlorate (LiClO) 4 ) Or lithium hexafluoroarsenate (LiAsF) 6 ) At least one of them.
Preferably, the conductive agent includes at least one of conductive carbon black, industrial furnace black, high temperature graphitized carbon black, acetylene black, carbon nanofibers, single wall carbon nanotubes, multi-wall carbon nanotubes, single or multi-layer graphene.
Preferably, the adhesive includes at least one of polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), vinylidene fluoride (VF 2), polyacrylic acid (PAA), styrene Butadiene Rubber (SBR), polyamide (PAI), polyvinyl alcohol (PVA), polyethyleneimine (PEI), or Polyimide (PI).
Preferably, the solvent includes at least one of Ethylene Carbonate (EC), propylene Carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl Butyrate (MB), ethyl Propionate (EP), dimethyl sulfoxide (DMSO), acetophenone, benzoate, and ethyl benzoate; more preferably, the boiling point of the solvent is greater than or equal to 150 ℃.
More preferably, the solvent comprises ethylene carbonate and propylene carbonate, and the volume ratio of the ethylene carbonate to the propylene carbonate is 1:1.
the second object of the present invention is to provide a thick electrode manufactured by the manufacturing method of the thick electrode;
preferably, the thick electrode is a positive electrode of a lithium ion battery or a negative electrode of the lithium ion battery.
Preferably, the thick electrode has a thickness of 100 μm to 1000 μm.
A third object of the present invention is to provide the use of the thick electrode in the field of lithium ion batteries; including but not limited to the preparation of lithium ion batteries comprising said thick electrodes, the preparation of electrical appliances comprising said thick electrodes, etc., are within the scope of the present invention.
Compared with the prior art, the invention has the beneficial effects that: the preparation method provided by the invention avoids the defects that the conventional process is easy to crack, has poor bonding capability, cannot realize industrial production and the like when the thick electrode is prepared; compared with the traditional thick electrode, the thick electrode prepared by the invention has solid porous property, and has the effect of improving the ion conductivity and the electron conductivity efficiency, so that the thick electrode has the effects of improving the charging capacity and the multiplying power performance. Meanwhile, the preparation process does not need solvents such as N-methyl pyrrolidone (NMP), saves cost, does not need the baking or sintering process of the pole piece, does not have unsafe gas emission, and is more environment-friendly and safer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 discloses a graph of test example gram capacity versus cycle number performance;
fig. 2 discloses a plot of area capacity versus cycle number performance for the test examples.
Detailed Description
The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and detailed description, but it will be understood by those skilled in the art that the examples described below are some, but not all, examples of the present invention, and are intended to be illustrative of the present invention only and should not be construed as limiting the scope of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The invention is carried out by the following specific embodiments: a method for preparing a thick electrode, comprising the steps of: and fully mixing the electrode active components, lithium salt, a conductive agent, an adhesive and a solvent, heating the mixed slurry to 110-180 ℃, compositing the heated mixed slurry with a current collector, and cooling to obtain the thick electrode.
It should be noted that the "heating the mixed slurry to 110 ℃ to 180 ℃ is the only heating operation involved in the present invention, i.e., the present invention does not include a drying step in the preparation method of the thick electrode; meanwhile, the thick electrode prepared by the invention does not need other heating operations (such as baking or sintering and other conventional steps) when the battery is assembled.
It should also be noted that, in the process of heating the mixed slurry to 110-180 ℃, the operator should perform the process of compounding the mixed slurry with the current collector as soon as possible, i.e. to ensure that the mixed slurry is compounded while it is hot.
When the temperature is raised, the specific binder can dissolve in the specific organic solvent and form a gel, but at room temperature the binder separates from the solvent and forms a continuous binder-solvent network, i.e. a network-interwoven structure of bicontinuous electrolytes. The gel structure of the adhesive-solvent at high temperature is represented by: the homogenized glue solution is mixed with the electrode raw material and forms a cross-linked structure, and when the temperature is reduced to room temperature, the adhesive is separated from the solvent, the adhesive plays a conventional bonding role, and the separated solvent is uniformly fixed in the inner pores of the thick electrode to play a role of electrolyte. Specifically, the binder of the present invention forms a uniform suspension with the electrode active ingredient, lithium salt, conductive agent and solvent, and when the suspension cools, the binder phase separates, carrying the electrode active ingredient particles and lithium salt, forming a continuous binder (electrode active ingredient and lithium salt) -solvent (conductive agent) network.
As a preferred embodiment, the temperature of the mixed slurry is 112 ℃ to 172 ℃; specifically including but not limited to: 112. 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 172 (°c); as a more preferred embodiment, the temperature of the mixed slurry is 112 to 145 ℃, and the adhesive can be softened at a high temperature repeatedly at the temperature, and the fluidity is easy to apply.
As a preferred embodiment, the thickness of the thick electrode includes, but is not limited to, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 (μm).
As a preferred embodiment, the raw material composition of the thick electrode includes: according to weight percentage, the electrode active component is 60% -98%, the conductive agent is 0.1% -40%, the adhesive is 0.1% -40%, and the solvent accounts for 5% -50% of the total mass of the active component, the conductive agent and the adhesive; as a preferred embodiment, the molar mass of the lithium salt in the solvent is 0.1mol/L to 8mol/L.
As a preferred embodiment, the compounding of the mixed slurry with the current collector includes: the mixed slurry is coated on the current collector, or the mixed slurry is bonded to the current collector after being rolled.
As a preferred embodiment, the current collector includes, but is not limited to, copper foil, aluminum foil, carbon coated copper foil, carbon coated aluminum foil, composite copper foil, composite aluminum foil, molybdenum foil, or stainless steel sheet.
As a preferred embodiment, the thorough mixing comprises: firstly, uniformly mixing the electrode active component, the conductive agent and the adhesive for the first time, then adding a lithium salt solution consisting of the lithium salt and the solvent, and uniformly mixing for the second time to obtain the mixed slurry.
As a preferred embodiment, after heating the mixed slurry, the mixed slurry is compounded with a current collector as much as possible before the mixed slurry is not cooled, i.e., the "hot mixed slurry is compounded with a current collector", and the skilled person should accomplish this in a short time, but the small-amplitude cooling of the mixed slurry, which is inevitably caused during the compounding with a current collector, does not affect the implementation of the technical solution of the present invention.
As a preferred embodiment, the lithium salt includes at least one of lithium bis (trifluoromethane) sulfonyl imide, lithium hexafluorophosphate, or lithium dioxaborate; as a more preferred embodiment, the lithium salt is selected from lithium bis (trifluoromethane) sulfonimide which is insensitive to moisture; however, when lithium hexafluorophosphate or lithium dioxalate borate is selected, the requirements on the water content of the operation process environment are more strict, and the working procedures such as preparation, coating, slicing and the like of the positive electrode slurry are all required to be in a relatively dry test environment.
Example 1
The active material, the conductive agent, the lithium salt, and the binder were dissolved in a solvent, heated to 112 ℃, continuously stirred, and a gel-like mixture was obtained by mixing uniformly, coating the mixture on a current collector copper foil while it was hot, coating the thickness of 100 μm, and obtaining eight thick electrodes (the eight thick electrodes correspond to the specific raw material components of examples 1-1, 1-2 in this order.) of this example to 1-8 after cooling.
Wherein the percentage values given for the active substance, the conductive agent and the adhesive refer to: the weight percentages of the active substances, the conductive agent and the adhesive are respectively ensured to be 100 percent. The molar concentration given for lithium salts refers to: molar concentration of lithium salt in the solvent.
TABLE 1
Example 2
Substantially the same as in examples 1-2, except that: heating to 150 ℃, and coating thickness of 500 μm; and a thick electrode of this embodiment was obtained.
Example 3
Substantially the same as in examples 1-2, except that: heating to 172 ℃, and coating thickness of 1000 μm; and a thick electrode of this embodiment was obtained.
Comparative example 1
conv (60 μm) electrode: fully mixing lithium iron phosphate (96.5%), conductive carbon black (1.5%) and polyvinylidene (2%) in a solvent N-methyl pyrrolidone to obtain positive electrode slurry; the positive electrode slurry was coated on a current collector aluminum foil to a thickness of 60 μm, followed by drying in an oven at 100 ℃ to remove the solvent and obtain a pole piece.
Comparative example 2
conv (125 μm) electrode: exactly the same as comparative example 1, the only difference was that the coating thickness was 125. Mu.m.
Test examples
The double performance of the thick electrode prepared in each of the above examples was compared with that of the thick electrode prepared in the comparative example. The test method comprises the steps of respectively carrying out charge and discharge at the multiplying power of C/20, C/10, C/5, C/2, 1C, 2C, 3C, 5C and 10C in a specific voltage test interval of the battery, cycling for five times at each multiplying power, keeping the charge and discharge interval time of 10min each cycle, recording the gram capacity of each example and comparative example in each cycle, and calculating the average value of the gram capacity obtained for five times, wherein the average value is shown in the following table 1.
A plot of average gram capacity versus scatter distribution of number of cycles for examples 1-2, comparative example 1 and comparative example 2 is given in figure 1.
Meanwhile, in the present test example, the area capacity at different rates of charge and discharge cycles (average value is measured in five cycle tests in the same manner) of examples 1-2, comparative example 1 and comparative example 2 was additionally compared with the scatter distribution of the number of cycles as shown in fig. 2.
TABLE 1
While the invention has been illustrated and described with reference to specific embodiments, it is to be understood that the above embodiments are merely illustrative of the technical aspects of the invention and not restrictive thereof; those of ordinary skill in the art will appreciate that: modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some or all of the technical features thereof, without departing from the spirit and scope of the present invention; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions; it is therefore intended to cover in the appended claims all such alternatives and modifications as fall within the scope of the invention.
Claims (10)
1. A method for preparing a thick electrode, comprising the steps of: and fully mixing the electrode active components, lithium salt, a conductive agent, an adhesive and a solvent, heating the mixed slurry to 110-180 ℃, compositing the heated mixed slurry with a current collector, and cooling to obtain the thick electrode.
2. The method of manufacturing a thick electrode according to claim 1, wherein the electrode active component comprises at least one of lithium cobaltate, lithium iron phosphate, ternary material, lithium-rich manganese-based material, or lithium manganate;
alternatively, the electrode active component includes at least one of a graphite material, amorphous carbon, a titanium oxide, or a silicon carbon composite.
3. The method of manufacturing a thick electrode according to claim 1, wherein the lithium salt comprises at least one of lithium tetrafluoroborate, lithium bis-sulfonimide, lithium difluorophosphate, lithium bis (trifluoromethane) sulfonimide, lithium hexafluorophosphate, lithium dioxalate borate, lithium 4, 5-dicyano-trifluoromethylimidazole, lithium perchlorate, or lithium hexafluoroarsenate.
4. The method of claim 1, wherein the conductive agent comprises at least one of conductive carbon black, industrial furnace black, high temperature graphitized carbon black, acetylene black, carbon nanofibers, single wall carbon nanotubes, multi wall carbon nanotubes, single layer or multi layer graphene.
5. The method of manufacturing a thick electrode according to claim 1, wherein the adhesive comprises at least one of polyvinylidene fluoride, polyethylene oxide, polyvinylidene fluoride-hexafluoropropylene, vinylidene fluoride, polyacrylic acid, styrene-butadiene rubber, polyamide, polyvinyl alcohol, polyethyleneimine, or polyimide.
6. The method for producing a thick electrode according to claim 1, wherein the solvent comprises at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methyl butyrate, ethyl propionate, dimethyl sulfoxide, acetophenone, benzoate, and ethyl benzoate;
preferably, the boiling point of the solvent is greater than or equal to 150 ℃.
7. The method for producing a thick electrode according to claim 6, wherein the solvent comprises ethylene carbonate and propylene carbonate, and the volume ratio of the ethylene carbonate to the propylene carbonate is 1:1.
8. a thick electrode produced by the method for producing a thick electrode according to any one of claims 1 to 7;
preferably, the thick electrode is a positive electrode of a lithium ion battery or a negative electrode of the lithium ion battery.
9. The thick electrode of claim 8 having a thickness of 100 μm to 1000 μm.
10. Use of the thick electrode of claim 8 in the field of lithium ion batteries.
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