CN116845246A - Electrode and lithium ion battery - Google Patents
Electrode and lithium ion battery Download PDFInfo
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- CN116845246A CN116845246A CN202310547331.6A CN202310547331A CN116845246A CN 116845246 A CN116845246 A CN 116845246A CN 202310547331 A CN202310547331 A CN 202310547331A CN 116845246 A CN116845246 A CN 116845246A
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 24
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 24
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 151
- 239000002245 particle Substances 0.000 claims abstract description 123
- 239000011149 active material Substances 0.000 claims abstract description 89
- 239000011148 porous material Substances 0.000 claims abstract description 37
- 239000013543 active substance Substances 0.000 claims abstract description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 36
- 239000011163 secondary particle Substances 0.000 claims description 32
- 239000011164 primary particle Substances 0.000 claims description 30
- 239000006258 conductive agent Substances 0.000 claims description 24
- 239000011230 binding agent Substances 0.000 claims description 20
- 239000002041 carbon nanotube Substances 0.000 claims description 19
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 19
- 239000007774 positive electrode material Substances 0.000 claims description 11
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 10
- 239000000919 ceramic Substances 0.000 claims description 9
- HPTYUNKZVDYXLP-UHFFFAOYSA-N aluminum;trihydroxy(trihydroxysilyloxy)silane;hydrate Chemical compound O.[Al].[Al].O[Si](O)(O)O[Si](O)(O)O HPTYUNKZVDYXLP-UHFFFAOYSA-N 0.000 claims description 8
- 229910052621 halloysite Inorganic materials 0.000 claims description 8
- 239000007773 negative electrode material Substances 0.000 claims description 7
- 239000006183 anode active material Substances 0.000 claims description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 3
- JEWHCPOELGJVCB-UHFFFAOYSA-N aluminum;calcium;oxido-[oxido(oxo)silyl]oxy-oxosilane;potassium;sodium;tridecahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.O.O.O.[Na].[Al].[K].[Ca].[O-][Si](=O)O[Si]([O-])=O JEWHCPOELGJVCB-UHFFFAOYSA-N 0.000 claims description 2
- JYIBXUUINYLWLR-UHFFFAOYSA-N aluminum;calcium;potassium;silicon;sodium;trihydrate Chemical compound O.O.O.[Na].[Al].[Si].[K].[Ca] JYIBXUUINYLWLR-UHFFFAOYSA-N 0.000 claims description 2
- 229960000892 attapulgite Drugs 0.000 claims description 2
- 239000006229 carbon black Substances 0.000 claims description 2
- 239000002134 carbon nanofiber Substances 0.000 claims description 2
- 229910052620 chrysotile Inorganic materials 0.000 claims description 2
- 229910001603 clinoptilolite Inorganic materials 0.000 claims description 2
- 229910052625 palygorskite Inorganic materials 0.000 claims description 2
- 229910001743 phillipsite Inorganic materials 0.000 claims description 2
- 239000004575 stone Substances 0.000 claims description 2
- CWBIFDGMOSWLRQ-UHFFFAOYSA-N trimagnesium;hydroxy(trioxido)silane;hydrate Chemical compound O.[Mg+2].[Mg+2].[Mg+2].O[Si]([O-])([O-])[O-].O[Si]([O-])([O-])[O-] CWBIFDGMOSWLRQ-UHFFFAOYSA-N 0.000 claims description 2
- 239000003792 electrolyte Substances 0.000 abstract description 17
- 150000002500 ions Chemical class 0.000 abstract description 10
- 239000000969 carrier Substances 0.000 abstract description 5
- 238000009792 diffusion process Methods 0.000 abstract description 5
- 238000013508 migration Methods 0.000 abstract description 5
- 230000005012 migration Effects 0.000 abstract description 5
- 230000002349 favourable effect Effects 0.000 abstract description 4
- 238000009736 wetting Methods 0.000 abstract 1
- 239000006245 Carbon black Super-P Substances 0.000 description 37
- 239000001768 carboxy methyl cellulose Substances 0.000 description 22
- 239000002033 PVDF binder Substances 0.000 description 17
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 17
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 15
- 229910052782 aluminium Inorganic materials 0.000 description 15
- 230000005540 biological transmission Effects 0.000 description 15
- 239000000463 material Substances 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- 239000010439 graphite Substances 0.000 description 14
- 229910002804 graphite Inorganic materials 0.000 description 14
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical group [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 13
- 239000011267 electrode slurry Substances 0.000 description 13
- 239000011888 foil Substances 0.000 description 13
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 13
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 13
- 229920003048 styrene butadiene rubber Polymers 0.000 description 13
- 238000002156 mixing Methods 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 11
- 238000000576 coating method Methods 0.000 description 11
- 238000002360 preparation method Methods 0.000 description 11
- 238000001035 drying Methods 0.000 description 10
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 9
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 9
- 239000011889 copper foil Substances 0.000 description 9
- 238000005520 cutting process Methods 0.000 description 9
- 230000001105 regulatory effect Effects 0.000 description 9
- 238000005096 rolling process Methods 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 239000006256 anode slurry Substances 0.000 description 5
- 239000003125 aqueous solvent Substances 0.000 description 5
- 230000008595 infiltration Effects 0.000 description 5
- 238000001764 infiltration Methods 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 4
- 238000005056 compaction Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 230000037427 ion transport Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000004806 packaging method and process Methods 0.000 description 4
- 229920000573 polyethylene Polymers 0.000 description 4
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 4
- 229910015872 LiNi0.8Co0.1Mn0.1O2 Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- -1 nickel-cobalt-aluminum Chemical compound 0.000 description 3
- 230000032258 transport Effects 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical class [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- 229920006255 plastic film Polymers 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 102000004310 Ion Channels Human genes 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 1
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005524 ceramic coating Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000006232 furnace black Substances 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 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
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002195 synergetic effect Effects 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
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/664—Ceramic materials
-
- 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
-
- 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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides an electrode and a lithium ion battery, wherein the electrode comprises a current collector and an active material layer arranged on the surface of the current collector, and the active material layer comprises an active material and a porous ceramic material; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is more than or equal to 8; the pore volume of the porous ceramic material is more than or equal to 0.1cm 3 /g; and the mass fraction of the porous ceramic material added is less than or equal to 6 percent based on 100 percent of the mass of the electrode. The invention introduces porous ceramic material with abundant reserves and low price into the active material layer of the electrode, and the porous junction thereofThe electrolyte is favorable for wetting the electrode, a good ion conduction path is formed, the tortuosity of lithium ion diffusion is reduced, the migration capability of carriers is improved, and the rate performance and the cycle life of the battery can be further improved.
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to an electrode and a lithium ion battery.
Background
The lithium ion battery has high specific energy density, long cycle life and no memory effect, and is widely applied to the fields of mobile phone digital products, unmanned aerial vehicles, electric vehicles, power grid energy storage and the like. The electrode of the lithium ion battery is formed by uniformly mixing an active substance, a binder and a conductive agent and then adhering the mixture to a current collector, and the performance of the positive and negative plates of the lithium ion battery plays a decisive role in the discharge capacity, voltage platform, cycle, rate performance and the like of the battery.
Currently, due to the rapid development of electric vehicles, there is a need for batteries having higher energy density. CN107819154a discloses a high energy density lithium ion power battery. The battery comprises a positive plate, a negative plate, a diaphragm, electrolyte and a battery shell accessory; the positive plate consists of a positive current collector, a positive material coated on the surface of the positive current collector, a positive conductive agent and a positive binder; the negative plate consists of a negative current collector, a negative material coated on the surface of the negative current collector, a negative conductive agent and a negative binder, wherein the positive material is a nickel-cobalt-manganese or nickel-cobalt-aluminum ternary positive material, and the negative material is silicon carbide or silicon oxide coated by a conductive carbon source. CN106486694B discloses a ternary battery with high energy density and a preparation method thereof, and the ternary battery with high energy density is obtained through collocation of a modified silicon-carbon material and a ternary material. The above patents employ high capacity electrode materials for improving the energy density of the battery.
CN113097567B discloses a method for manufacturing a high energy density soft package battery, comprising the following steps: step 1: wrapping an aluminum foil auxiliary electrode on the bottom of a lithium battery winding core, isolating and insulating the battery winding core and the aluminum foil auxiliary electrode by using an isolating film, and assembling to obtain a soft package battery; step 2: injecting electrolyte 1 into the soft package battery obtained in the step 1, and pre-charging by using an aluminum foil auxiliary electrode after sealing; step 3: and taking out the aluminum foil auxiliary electrode after the precharge is finished, removing the free electrolyte 1, injecting the electrolyte 2, and performing post-treatment to obtain the high-energy-density soft-package battery. According to the lithium ion battery, the aluminum foil auxiliary electrode is preset at the bottom of the lithium ion battery winding core, and the capacity and the energy density of the lithium ion battery are improved through the synergistic effect of the aluminum foil auxiliary electrode and the electrolyte 1 containing the additive.
In a high-energy-density battery, the electrode has the characteristics of large thickness and low porosity, which leads to the increase of the length and tortuosity of an ion transmission channel in the electrode, the ion transmission channel in the electrode is formed by electrolyte filled in the pores of the electrode, that is, the ion transmission channel is formed by connecting the pores in the electrode, the increase of the thickness of the electrode inevitably leads to the increase of the length of the channel, and the decrease of the porosity of the electrode inevitably leads to the increase of the tortuosity of the channel, so that the rate performance of the battery is poor.
Therefore, there is a need to reduce the tortuosity of the ion transport channels in high energy density battery electrodes, thereby improving the rate capability of the battery.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide an electrode and a lithium ion battery. The porous ceramic material with abundant reserves and low price is introduced into the active material layer of the electrode, the porous structure of the porous ceramic material is favorable for the electrolyte to infiltrate the electrode, a good ion conducting path is formed, the tortuosity of lithium ion diffusion is reduced, the migration capability of carriers is improved, and the multiplying power performance and the cycle life of the battery can be further improved.
To achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an electrode comprising a current collector and an active material layer disposed on a surface of the current collector, the active material layer comprising an active material and a porous ceramic material;
the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is more than or equal to 8; the pore volume of the porous ceramic material is more than or equal to 0.1cm 3 /g；
And the mass fraction of the porous ceramic material added is less than or equal to 6 percent based on 100 percent of the mass of the electrode.
In the present invention, the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material may be, for example, 8, 10, 15, 20, 30, 50, 70, 100, 120, 150, 200, 300, 500, 1000, 1500, 2000, 2500, 3000 or the like.
The pore volume of the porous ceramic material can be, for example, 0.1cm 3 /g、0.11cm 3 /g、0.12cm 3 /g、0.13cm 3 /g、0.15cm 3 /g、0.17cm 3 /g、0.2cm 3 /g、0.22cm 3 /g、0.25cm 3 /g、0.27cm 3 /g、0.3cm 3 /g、0.32cm 3 /g、0.35cm 3 /g、0.4cm 3 /g、0.45cm 3 /g、0.5cm 3 /g、0.55cm 3 /g、0.6cm 3 /g、0.65cm 3 /g、0.7cm 3 /g、0.75cm 3 /g、0.8cm 3 /g、0.85cm 3 /g、0.90cm 3 /g、0.95cm 3 /g、1.00cm 3 /g、1.05cm 3 /g、1.10cm 3 /g、1.15cm 3 /g、1.20cm 3 /g、1.25cm 3 /g、130cm 3 /g、1.35cm 3 /g、1.40cm 3 /g、1.45cm 3 /g、1.50cm 3 /g、1.55cm 3 /g or 1.60cm 3 /g, etc.
The porous ceramic material may be added in an amount of, for example, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.7%, 0.5%, 0.3%, or 0.1%.
The pore volume of the porous ceramic material was measured by the BET method.
The porous ceramic material has excellent flame retardant property and rich morphology property, is used as electrode surface coating material or diaphragm surface ceramic coating material in the prior art to improve the safety performance of the battery, but increases the internal resistance of the battery, and is unfavorable for the exertion of the multiplying power performance of the battery.
The invention provides an electrode, which is characterized in that porous ceramic materials with abundant reserves and low price are introduced into an active substance layer of the electrode, and when the active substance and the porous ceramic materials simultaneously meet the following conditions: the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is more than or equal to 8, and the pore volume of the porous ceramic material is more than or equal to 0.1cm 3 /g; the mass fraction of the porous ceramic material added is less than or equal to 6 percent based on 100 percent of the mass of the electrodeUnder various conditions, the porous ceramic material can be well filled in the pores among the active material particles, and the porous structure of the porous ceramic material is favorable for the infiltration of electrolyte to the electrode, so that a good ion conducting path can be formed, the tortuosity of lithium ion diffusion is reduced, the migration capability of carriers is improved, and the rate performance and the cycle life of the battery can be further improved; meanwhile, the porous ceramic material has excellent electronic insulating property, does not provide electrons to become parasitic reaction sites, and can play a positive role in improving the battery performance;
in addition, by controlling the particle size and the addition amount, the porous ceramic material does not influence the electron transmission of the electrode, has no obvious influence on the resistance of the electrode plate, does not influence the compaction density of the electrode plate, and does not reduce the energy density of the battery.
Preferably, the ratio of the D90 particle size of the active material to the D90 particle size of the porous ceramic material is 8 to 1500, and may be, for example, 8, 10, 15, 20, 30, 50, 70, 100, 120, 150, 200, 300, 500, 1000, 1500, or the like.
Preferably, the D90 particle size of the active material is 3 to 30. Mu.m, for example, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 21 μm, 23 μm, 25 μm, 27 μm, 29 μm or 30 μm, etc.
The type of the electrode is not limited in the present invention, and the electrode may be a positive electrode or a negative electrode; accordingly, the active material of the present invention may be a positive electrode active material or a negative electrode active material.
Preferably, the active material is a positive electrode active material, and the porous ceramic material may be added in an amount of 0.1 to 3% by mass, for example, 3%, 2.5%, 2%, 1.5%, 1%, 0.7%, 0.5%, 0.3%, 0.1%, or the like, based on 100% by mass of the electrode.
In the invention, if the mass fraction of the porous ceramic material is too high, part of the ceramic material is difficult to enter the pores between the positive electrode active materials, so that an electron transmission channel is blocked, and the energy density is reduced; if the mass fraction of the porous ceramic material is too low, the ability of the porous ceramic material to improve the infiltration of the electrolyte into the active material and reduce the tortuosity of the lithium ion transmission channel is deteriorated.
The present invention is not limited to the kind of the positive electrode active material, and includes, but is not limited to, at least one of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium iron phosphate, and lithium cobalt oxide.
Preferably, the ratio of the D90 particle diameter of the positive electrode active material to the D90 particle diameter of the porous ceramic material is 8 to 1000, and may be, for example, 8, 10, 15, 20, 30, 50, 70, 100, 120, 150, 200, 300, 500, 700, 900, 1000, or the like.
In the invention, if the ratio of the D90 particle size of the positive electrode active material to the D90 particle size of the porous ceramic material is too large, the particle size of the porous ceramic material is too small, which is not beneficial to forming a good ion transmission channel; if the ratio of the D90 particle diameter of the positive electrode active material to the D90 particle diameter of the porous ceramic material is too small, the particle diameter of the porous ceramic material is too large to be effectively filled between the active material particles, the compaction density of the electrode sheet is reduced to reduce the energy density of the battery, and the conductive agent is prevented from forming a good electron transport channel to reduce the rate performance.
The D90 particle diameter of the positive electrode active material is preferably 3 to 20. Mu.m, and may be, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 20 μm, or the like.
Preferably, the active material is a negative electrode active material, and the porous ceramic material may be added in an amount of 0.1 to 5% by mass, for example, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.7%, 0.5%, 0.3%, 0.1%, or the like, based on 100% by mass of the electrode.
In the invention, if the mass fraction of the porous ceramic material is too high, part of the ceramic material is difficult to enter the pores between the anode active materials, so that an electron transmission channel is blocked, and the energy density is reduced; if the mass fraction of the porous ceramic material is too low, the ability of the porous ceramic material to improve the infiltration of the electrolyte into the active material and reduce the tortuosity of the lithium ion transmission channel is deteriorated.
The present invention is not limited in the kind of the anode active material, and includes, but is not limited to, graphite and/or silicon carbon materials.
Preferably, the ratio of the D90 particle diameter of the anode active material to the D90 particle diameter of the porous ceramic material is 28 to 1500, and may be 28, 30, 50, 70, 100, 120, 150, 200, 300, 500, 700, 900, 1000, 1200, 1400, 1500, or the like, for example.
In the invention, if the ratio of the D90 particle size of the negative electrode active material to the D90 particle size of the porous ceramic material is too large, the particle size of the porous ceramic material is too small, which is not beneficial to forming a good ion transmission channel, and if the ratio of the D90 particle size of the negative electrode active material to the D90 particle size of the porous ceramic material is too small, the particle size of the porous ceramic material is too large, and cannot be effectively filled between the active material particles, the compaction density of the pole pieces is reduced, thereby reducing the energy density of the battery, and the conductive agent is prevented from forming a good electron transmission channel, thereby reducing the rate performance.
Preferably, the D90 particle diameter of the negative electrode active material is 10 to 30. Mu.m, for example, 10. Mu.m, 13. Mu.m, 15. Mu.m, 17. Mu.m, 19. Mu.m, 21. Mu.m, 23. Mu.m, 25. Mu.m, 27. Mu.m, 29. Mu.m, 30. Mu.m, or the like.
The porous ceramic material preferably has a D90 particle diameter of 1 μm or less, and may be, for example, 950nm, 900nm, 850nm, 800nm, 750nm, 700nm, 650nm, 600nm, 550nm, 500nm, 450nm, 400nm, 350nm, 300nm, 250nm, 200nm, 150nm, 100nm, 90nm, 80nm, 70nm, 60nm, 50nm, 40nm, 30nm, or 20nm, etc., preferably 500nm or less, and more preferably 20 to 350nm.
In the invention, when the D90 particle size of the porous ceramic material is too large, the porous ceramic material cannot be well filled into pores among active materials, so that an electron channel of an electrode is blocked, the electrochemical performance of a battery is influenced, the energy density is reduced and the like; when the D90 particle diameter of the porous ceramic material is too small, the effect of improving the ion channel is not obvious.
Preferably, the porous ceramic material has a pore volume of 0.12-1.50cm 3 Per g, for example, may be 0.12cm 3 /g、0.13cm 3 /g、0.15cm 3 /g、0.17cm 3 /g、0.2cm 3 /g、0.22cm 3 /g、0.25cm 3 /g、0.27cm 3 /g、0.3cm 3 /g、0.32cm 3 /g、0.35cm 3 /g、0.4cm 3 /g、0.45cm 3 /g、0.5cm 3 /g、0.55cm 3 /g、0.6cm 3 /g、0.65cm 3 /g、0.7cm 3 /g、0.75cm 3 /g、0.8cm 3 /g、0.85cm 3 /g、0.90cm 3 /g、0.95cm 3 /g、1.00cm 3 /g、1.05cm 3 /g、1.10cm 3 /g、1.15cm 3 /g、1.20cm 3 /g、1.25cm 3 /g、130cm 3 /g、1.35cm 3 /g、1.40cm 3 /g、1.45cm 3 /g or 1.50cm 3 /g, etc.
Preferably, the specific surface area of the porous ceramic material is 10m or more 2 /g, for example, may be 11m 2 /g、20m 2 /g、30m 2 /g、40m 2 /g、50m 2 /g、70m 2 /g、90m 2 /g、100m 2 /g、120m 2 /g、150m 2 /g、170m 2 /g、200m 2 /g、220m 2 /g、250m 2 /g、270m 2 /g、300m 2 /g、320m 2 /g、350m 2 /g、370m 2 /g、400m 2 /g、450m 2 /g、500m 2 /g、550m 2 /g、600m 2 /g、650m 2 /g、700m 2 /g、750m 2 /g、800m 2 /g、850m 2 /g or 900m 2 Per g, etc., preferably 20-800m 2 /g。
Preferably, the porous ceramic material comprises porous primary particles and/or porous secondary particles.
In the present invention, porous primary particles refer to particles themselves having a porous structure; the porous secondary particles are particles formed by combining primary particles with smaller particle sizes, and also have a loose and porous structure.
Preferably, the porous primary particles comprise porous ceramic particles and/or tubular porous ceramic material.
In the present invention, the porous ceramic particles refer to ceramic materials having a porous structure in nature.
Preferably, the porous ceramic particles include at least one of attapulgite, clinoptilolite, phillipsite and medical stone.
Preferably, the tubular porous ceramic material comprises at least one of halloysite, chrysotile and imogolite.
The porous primary particles preferably have a D90 particle diameter of 1 μm or less, and may be, for example, 1 μm, 950nm, 900nm, 850nm, 800nm, 750nm, 700nm, 650nm, 600nm, 550nm, 500nm, 450nm, 400nm, 350nm, 300nm, 250nm, 200nm, 150nm, 100nm, 90nm, 80nm, 70nm, 60nm, 50nm, 45nm, 40nm, 30nm, 20nm or the like, preferably 500nm or less, and more preferably 20 to 350nm.
Preferably, the porous secondary particles comprise SiO 2 Porous secondary particles, tiO 2 Porous secondary particles and Al 2 O 3 At least one of the porous secondary particles.
Preferably, the porous secondary particles are formed by combining primary particles.
In the invention, the SiO 2 The porous secondary particles are made of SiO 2 Primary particles are combined; the TiO 2 The porous secondary particles are made of TiO 2 Primary particles are combined; the Al is 2 O 3 The porous secondary particles are made of Al 2 O 3 The primary particles are combined.
Preferably, the porous secondary particles formed by combining the primary particles are manufactured by a gas phase method.
Preferably, the primary particles have a D90 particle diameter of 500nm or less, for example, 500nm, 450nm, 400nm, 350nm, 300nm, 250nm, 200nm, 150nm, 100nm, 90nm, 80nm, 70nm, 60nm, 50nm, 40nm, 30nm, 20nm, 10nm or 5nm, etc., preferably 5 to 350nm.
Preferably, the D90 particle diameter of the porous secondary particles is 500nm or less, for example, 500nm, 450nm, 400nm, 350nm, 300nm, 250nm, 200nm, 150nm, 100nm, 90nm, 80nm, 70nm, 60nm, 50nm, 40nm, 30nm or 20nm, etc., preferably 20 to 350nm.
Preferably, the active material layer further includes a binder and a conductive agent.
Preferably, the conductive agent includes carbon nanotubes, vapor grown carbon fibers, and/or carbon black including acetylene black and/or furnace black, and the like.
Preferably, the thickness of the active material layer is 10 to 100. Mu.m, for example, 10. Mu.m, 20. Mu.m, 30. Mu.m, 40. Mu.m, 50. Mu.m, 60. Mu.m, 70. Mu.m, 80. Mu.m, 90. Mu.m, 100. Mu.m, or the like.
Preferably, the active material layer has a porosity of 20-40%, for example, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, etc.
Illustratively, the present invention provides a method of preparing an electrode, the method comprising the steps of:
(1) Mixing a conductive agent and a binder to obtain a mixture;
(2) Mixing an active material, a porous ceramic material and the mixture, and adjusting the viscosity by using a solvent to obtain electrode slurry;
(3) And coating the electrode slurry on a current collector, and drying to obtain the electrode.
The electrode preparation method is simple and convenient, and the used materials are low in cost and suitable for commercial application and large-scale production.
In a second aspect, the present invention provides a lithium ion battery comprising an electrode according to the first aspect.
The numerical ranges recited herein include not only the above-listed point values, but also any point values between the above-listed numerical ranges that are not listed, and are limited in space and for the sake of brevity, the present invention is not intended to be exhaustive of the specific point values that the stated ranges include.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides an electrode, which is characterized in that porous ceramic materials with abundant reserves and low price are introduced into an active substance layer of the electrode, and when the active substance and the porous ceramic materials simultaneously meet the following conditions: d90 particle size of active material and porous ceramic materialThe ratio of the D90 particle size is more than or equal to 8, and the pore volume of the porous ceramic material is more than or equal to 0.1cm 3 /g; when the mass of the electrode is 100%, the porous ceramic material can be well filled in the pores among active material particles under the condition that the added mass fraction of the porous ceramic material is less than or equal to 6%, and the porous structure of the porous ceramic material is favorable for the infiltration of electrolyte to the electrode, so that a good ion conduction path can be formed, the tortuosity of lithium ion diffusion is reduced, the migration capability of carriers is improved, and the multiplying power performance and the cycle life of the battery can be further improved; meanwhile, the porous ceramic material with high specific surface area has excellent electronic insulating property, does not provide electrons to become parasitic reaction sites, and can play a positive role in improving the battery performance;
in addition, by controlling parameters such as particle size, addition amount and the like, the porous ceramic material does not influence the electron transmission of the electrode, so that the resistance of the electrode plate is not obviously influenced, the compaction density of the electrode plate is not influenced, and the energy density of the battery is not reduced.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments.
Example 1
The embodiment provides a positive electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is an aluminum foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 61 μm and the porosity was 31%;
the active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) having a D90 particle size of 18.25 μm; the porous ceramic material is halloysite tubular material, the D90 particle size is about 29nm, and the specific surface area is 48.87m 2 Per g, pore volume of 0.16cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 629.3, the conductive agent is Carbon Nanotube (CNT) and Super-P (SP), the binder is polyvinylidene fluoride (PVDF), and the mass of the active substance layer is that of the porous ceramic materialThe mass fraction of the porous ceramic material is 1%, the mass fraction of NCM811 is 95.2%, the mass fraction of the carbon nanotubes and Super-P is 1%, and the mass fraction of polyvinylidene fluoride is 1.8% calculated as 100%.
The embodiment also provides a preparation method of the positive electrode, which comprises the following steps:
uniformly mixing 1% of Carbon Nano Tube (CNT), 1% of Super-P (SP) and 1.8% of polyvinylidene fluoride (PVDF) in mass fraction under a low humidity environment, sequentially adding 95.2% of NCM811 and 1% of halloysite tubular material, uniformly mixing, and regulating viscosity by using NMP solvent to obtain anode slurry; and uniformly coating the prepared anode slurry on an aluminum foil, drying, and rolling and die-cutting to obtain the anode.
Example 2
The embodiment provides a positive electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is an aluminum foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 61 μm and the porosity was 31%;
the active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) having a D90 particle size of 18.25 μm; the porous ceramic material is SiO 2 Secondary particles formed by stacking primary particles, wherein the primary particles have a D90 particle diameter of about 16nm, the secondary particles have a D90 particle diameter of about 282nm, and a specific surface area of 114.56m 2 Per g, pore volume of 0.31cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 64.7, the conductive agent is Carbon Nanotube (CNT) and Super-P (SP), the binder is polyvinylidene fluoride (PVDF), the mass fraction of the porous ceramic material is 1%, the mass fraction of NCM811 is 95.2%, the mass fraction of carbon nanotube and Super-P is 1%, and the mass fraction of polyvinylidene fluoride is 1.8%, based on 100% of the mass of the active substance layer.
The embodiment also provides a preparation method of the positive electrode, which comprises the following steps:
uniformly mixing 1% Carbon Nanotube (CNT), 1% Super-P (SP) and 1.8% polyvinylidene fluoride (PVDF) in low humidity environment, and sequentially adding 95.2% NCM811 and 1% SiO 2 Secondary particles formed by stacking the primary particles are uniformly mixed, and are regulated to be sticky by using an NMP solvent to obtain positive electrode slurry; and uniformly coating the prepared anode slurry on an aluminum foil, drying, and rolling and die-cutting to obtain the anode.
Example 3
The embodiment provides a positive electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is an aluminum foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 61 μm and the porosity was 30%;
the active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) having a D90 particle size of 18.25 μm; the porous ceramic material is SiO 2 Secondary particles formed by stacking primary particles, wherein the primary particles have a D90 particle diameter of about 16nm, the secondary particles have a D90 particle diameter of about 282nm, and a specific surface area of 114.56m 2 Per g, pore volume of 0.31cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 64.7, the conductive agent is Carbon Nanotube (CNT) and Super-P (SP), the binder is polyvinylidene fluoride (PVDF), the mass fraction of the porous ceramic material is 2%, the mass fraction of NCM811 is 94.2%, the mass fraction of carbon nanotube and Super-P is 1%, and the mass fraction of polyvinylidene fluoride is 1.8%, based on the mass of the active substance layer as 100%.
The embodiment also provides a preparation method of the positive electrode, which comprises the following steps:
uniformly mixing Carbon Nano Tube (CNT) with mass fraction of 1%, super-P (SP) with polyvinylidene fluoride (PVDF) with mass fraction of 1% and 1.8% under low humidity environment, and sequentially adding NCM811 with mass fraction of 94.2% and SiO with mass fraction of 2% 2 Secondary particles formed by stacking the primary particles are uniformly mixed, and are regulated to be sticky by using an NMP solvent to obtain positive electrode slurry; will prepareAnd uniformly coating the anode slurry on an aluminum foil, drying, and rolling and die-cutting to obtain the anode.
Example 4
The embodiment provides a negative electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is copper foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 78 μm and the porosity was 36%;
the active material is graphite, and the D90 particle size of the active material is 28.80 mu m; the porous ceramic material is halloysite tubular material, the D90 particle size is about 29nm, and the specific surface area is 48.87m 2 Per g, pore volume of 0.16cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 993.1, the conductive agent is Super-P (SP), the binder is sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), and the mass fraction of the porous ceramic material is 2%, the mass fraction of graphite is 92.8%, the mass fraction of Super-P is 2%, the mass fraction of sodium carboxymethyl cellulose is 1.2%, and the mass fraction of styrene-butadiene rubber is 2% based on 100% of the mass of the active substance layer.
The embodiment also provides a preparation method of the negative electrode, which comprises the following steps:
under a conventional environment, uniformly mixing 2% of Super-P (SP), 1.2% of sodium carboxymethylcellulose (CMC) and 2% of styrene-butadiene rubber, sequentially adding 92.8% of graphite and 2% of halloysite tubular materials, uniformly mixing, and regulating viscosity with an aqueous solvent to obtain negative electrode slurry; and uniformly coating the prepared negative electrode slurry on a copper foil, drying, and rolling and die-cutting to obtain the negative electrode.
Example 5
The embodiment provides a negative electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is copper foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 78 μm and the porosity was 36%;
the active material is graphite, and the D90 particle size of the active material is 28.80 mu m; the porous ceramic material is SiO 2 Secondary particles comprising primary particles having a D90 particle diameter of about 7nm and a D90 particle diameter of about 171nm and a specific surface area of 333.99m, wherein the primary particles are stacked 2 Per g, pore volume of 0.75cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 168.4, the conductive agent is Super-P (SP), the binder is sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), and the mass fraction of the porous ceramic material is 2%, the mass fraction of graphite is 92.8%, the mass fraction of Super-P is 2%, the mass fraction of sodium carboxymethyl cellulose is 1.2%, and the mass fraction of styrene-butadiene rubber is 2% based on 100% of the mass of the active substance layer.
The embodiment also provides a preparation method of the negative electrode, which comprises the following steps:
under the conventional environment, super-P (SP) with the mass fraction of 2 percent, sodium carboxymethylcellulose (CMC) with the mass fraction of 1.2 percent and styrene-butadiene rubber with the mass fraction of 2 percent are uniformly mixed, and then 92.8 percent of graphite and 2 percent of SiO are sequentially added 2 Secondary particles formed by stacking the primary particles are uniformly mixed, and are regulated to be sticky by an aqueous solvent to obtain negative electrode slurry; and uniformly coating the prepared negative electrode slurry on a copper foil, drying, and rolling and die-cutting to obtain the negative electrode.
Example 6
The embodiment provides a negative electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is copper foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 78 μm and the porosity was 34%;
the active material is graphite, and the D90 particle size of the active material is 28.80 mu m; the porous ceramic material is SiO 2 Secondary particles comprising primary particles having a D90 particle diameter of about 7nm and a D90 particle diameter of about 171nm and a specific surface area of 333.99m, wherein the primary particles are stacked 2 Per g, pore volume of 0.75cm 3 /g; the active substanceThe ratio of the mass D90 particle size to the mass D90 particle size of the porous ceramic material is 168.4, the conductive agent is Super-P (SP), the binder is sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), and the mass fraction of the porous ceramic material is 4%, the mass fraction of graphite is 90.8%, the mass fraction of Super-P is 2%, the mass fraction of sodium carboxymethyl cellulose is 1.2%, and the mass fraction of styrene-butadiene rubber is 2% based on 100% of the mass of the active substance layer.
The embodiment also provides a preparation method of the negative electrode, which comprises the following steps:
under the conventional environment, super-P (SP) with the mass fraction of 2 percent, sodium carboxymethylcellulose (CMC) with the mass fraction of 1.2 percent and Styrene Butadiene Rubber (SBR) with the mass fraction of 2 percent are uniformly mixed, and then 90.8 percent of graphite and 4 percent of SiO are sequentially added 2 Secondary particles formed by stacking the primary particles are uniformly mixed, and are regulated to be sticky by an aqueous solvent to obtain negative electrode slurry; and uniformly coating the prepared negative electrode slurry on a copper foil, drying, and rolling and die-cutting to obtain the negative electrode.
Example 7
The embodiment provides a negative electrode, which comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the current collector is copper foil, and the active material layer comprises an active material, a porous ceramic material, a conductive agent and a binder; the thickness of the active material layer was 78 μm and the porosity was 33%;
the active material is graphite, and the D90 particle size of the active material is 28.80 mu m; the porous ceramic material is SiO 2 Secondary particles comprising primary particles having a D90 particle diameter of about 9nm and a D90 particle diameter of about 346nm and a specific surface area of 87.45m, wherein the secondary particles are packed 2 Per g, pore volume of 0.28cm 3 /g; the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is 83.2, the conductive agent is Super-P (SP), the binder is sodium carboxymethylcellulose (CMC) and styrene-butadiene rubber (SBR), the mass fraction of the porous ceramic material is 5%, the mass fraction of graphite is 89.8%, the mass fraction of Super-P is 2% based on the mass of the active substance layer as 100%,the mass fraction of the sodium carboxymethyl cellulose is 1.2%, and the mass fraction of the styrene-butadiene rubber is 2%.
The embodiment also provides a preparation method of the negative electrode, which comprises the following steps:
under the conventional environment, super-P (SP) with the mass fraction of 2 percent, sodium carboxymethylcellulose (CMC) with the mass fraction of 1.2 percent and Styrene Butadiene Rubber (SBR) with the mass fraction of 2 percent are uniformly mixed, and then 89.8 percent of graphite and 5 percent of SiO are sequentially added 2 Secondary particles formed by stacking the primary particles are uniformly mixed, and are regulated to be sticky by an aqueous solvent to obtain negative electrode slurry; and uniformly coating the prepared negative electrode slurry on a copper foil, drying, and rolling and die-cutting to obtain the negative electrode.
Example 8
The difference between this example and example 1 is that the D90 particle diameter of the porous ceramic material was adjusted to 37nm so that the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material was adjusted to 493.2, and the specific surface area of the porous ceramic material was adjusted to 53.37m accordingly 2 Per g, pore volume is adjusted to 0.17cm 3 And/g, the remainder being exactly the same as in example 1.
Example 9
The difference between this example and example 1 is that the D90 particle size of the porous ceramic material was adjusted to 52nm so that the ratio of the D90 particle size of the active material to the D90 particle size of the porous ceramic material was adjusted to 351.0, and the specific surface area of the porous ceramic material was adjusted to 61.65m accordingly 2 Per g, pore volume is adjusted to 0.18cm 3 And/g, the remainder being exactly the same as in example 1.
Example 10
The difference between this example and example 1 is that the D90 particle diameter of the porous ceramic material was adjusted to 16nm so that the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material was adjusted to 1140.6, and the specific surface area of the porous ceramic material was adjusted to 32.43m accordingly 2 Per g, pore volume is adjusted to 0.12cm 3 And/g, the remainder being exactly the same as in example 1.
Example 11
This example differs from example 1 in that the D90 particle size of the porous ceramic material was adjusted11nm, so that the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is adjusted to 1659.1, and the specific surface area of the porous ceramic material is adjusted to 30.89m 2 Per g, pore volume is adjusted to 0.11cm 3 And/g, the remainder being exactly the same as in example 1.
Example 12
This example is different from example 1 in that the mass fraction of the porous ceramic material is adjusted to 3.5%, and the rest is exactly the same as example 1.
Example 13
This example is different from example 1 in that the mass fraction of the porous ceramic material is adjusted to 4%, and the rest is exactly the same as example 1.
Example 14
This example is different from example 1 in that the mass fraction of the porous ceramic material is adjusted to 0.05%, and the rest is exactly the same as example 1.
Comparative example 1
This comparative example provides a positive electrode differing from example 1 in that no porous ceramic material, that is, no halloysite tubular material, is added to the active material layer, and the remainder is exactly the same as example 1.
The comparative example also provides a method for producing a positive electrode, which is different from example 1 in that the mass fraction of NCM811 is adjusted to 97.5%, the mass fraction of halloysite tubular material is adjusted to 0%, and the rest is exactly the same as example 1.
Comparative example 2
This comparative example provides a positive electrode differing from example 2 in that the particle diameter of the porous ceramic material is adjusted such that the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material is adjusted to 7, and the specific surface area of the porous ceramic material is adjusted to 38.42m 2 Per g, pore volume is adjusted to 0.11cm 3 And/g, the remainder being exactly the same as in example 2.
Comparative example 3
This comparative example provides a negative electrode differing from example 6 in that the mass fraction of the porous ceramic material was adjusted to 6.5%, and the rest was exactly the same as example 6.
Comparative example 4
This comparative example provides a negative electrode differing from example 6 in that the particle diameter of the porous ceramic material is adjusted such that the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material is adjusted to 7, and the specific surface area of the porous ceramic material is adjusted to 26.13m 2 Per g, pore volume is adjusted to 0.08cm 3 /g, and the mass fraction of the porous ceramic material was adjusted to 6.5%, the remainder was exactly the same as in example 6.
Performance testing
The positive electrodes provided in examples 1 to 3, examples 8 to 14 and comparative examples 1 to 2 were assembled with the negative electrode and the separator as a battery cell. The preparation method of the negative electrode comprises the following steps: under a conventional environment, uniformly mixing 2% of Super-P (SP), 1.2% of sodium carboxymethylcellulose (CMC) and 2% of Styrene Butadiene Rubber (SBR), then uniformly adding 94.8% of graphite, and mixing, and regulating viscosity by using an aqueous solvent; uniformly coating the prepared negative electrode slurry on a copper foil, drying, and rolling and die-cutting to obtain the negative electrode; sequentially stacking a negative electrode, a Polyethylene (PE) +ceramic diaphragm (with the thickness of 9 mu m+3 mu m) and a positive electrode into a battery core in a low-humidity environment, packaging the battery core in an aluminum plastic film, and placing the battery core in a high-temperature vacuum oven for baking; and transferring the battery cells into a glove box, injecting commercial electrolyte, and packaging to obtain the single-chip soft-package battery cell.
The negative electrodes provided in examples 4 to 7 and comparative examples 3 to 4 were assembled with a positive electrode and a separator as a battery cell. The preparation method of the positive electrode comprises the following steps: uniformly mixing 1% of Carbon Nano Tube (CNT) and 1.5% of polyvinylidene fluoride (PVDF) in mass fraction under a low humidity environment, then adding 97.5% of NCM811 anode material, and regulating viscosity by using NMP solvent; uniformly coating the prepared anode slurry on an aluminum foil, drying, and rolling and die-cutting to obtain the anode; sequentially stacking a negative electrode, a Polyethylene (PE) +ceramic diaphragm (with the thickness of 9 mu m+3 mu m) and a positive electrode into a battery core in a low-humidity environment, packaging the battery core in an aluminum plastic film, and placing the battery core in a high-temperature vacuum oven for baking; and transferring the battery cells into a glove box, injecting commercial electrolyte, and packaging to obtain the single-chip soft-package battery cell.
(1) First put capacity test
The battery after formation is fully charged by using a 0.15C constant-current constant-voltage mode, then is discharged by using a 0.33C constant-current mode, and the gram specific capacity of the first discharge is recorded after the discharge.
(2) Rate capability test
And charging in a constant-current and constant-voltage mode and discharging in a constant-current mode. Firstly, charging and discharging are carried out at 1C to obtain a reference discharge capacity; then, the double charging and double discharging test is carried out: in the double-charge test, the battery is charged at 2C and 3C respectively, and is discharged at 1C to obtain constant-current charge ratios at different multiplying powers, and the ratio of the discharge capacity corresponding to different charge multiplying powers to the reference discharge capacity is calculated; in the double-discharge test, the battery is charged at 1C, discharged at 2C and 3C respectively, and the ratio of the discharge capacity corresponding to different discharge rates to the reference discharge capacity is calculated.
(3) Cycle performance test
Charging the battery at 1C by adopting a constant-current and constant-voltage mode (cut-off current is 0.05C), placing for 10min, discharging at 1C by adopting a constant-current mode, and placing for 10min; and (3) performing a cycle test on the battery cell at room temperature to obtain the cycle number of the battery cell, wherein the cycle number is 80% of the capacity retention rate.
The test results are shown in Table 1.
TABLE 1
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Analysis:
from the results of examples 1 to 8, it is apparent that the porous ceramic material with abundant reserves and low cost is introduced into the active material layer of the electrode, the porous structure of the ceramic material can be filled with electrolyte, and the porous structure of the ceramic material facilitates the electrolyte to infiltrate the electrode, so that a good ion conductive path can be formed, the tortuosity of lithium ion diffusion is reduced, the migration capability of carriers is improved, and the rate performance and the cycle life of the battery can be further improved.
The particle size and the addition amount of the porous ceramic material are controlled, so that the porous ceramic material can be well filled in the pores among active material particles, and the electron transmission of the electrode is not affected. As is clear from the results of examples 1 and examples 9 to 11, when the D90 particle size of the porous ceramic material is too large, it cannot be well filled into the pores of the active material, which obstructs the carrier channel of the electrode, and affects the electrochemical performance and energy density of the battery; when the D90 particle size of the porous ceramic material is smaller, the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is higher, so that the porous ceramic material is mainly gathered at the pore opening of the active material, is difficult to enter the inside of the pore, cannot fill the whole pore, is unfavorable for improving the tortuosity of carrier transmission, and affects the multiplying power characteristics of the battery.
From the results of examples 1 and examples 12 to 14, it is understood that when the mass fraction of the porous ceramic material is high, it is difficult for part of the ceramic material to enter the pores of the active material and block the conductive network, affecting the electrochemical performance of the battery; when the mass fraction of the porous ceramic material is low, it is difficult to improve the infiltration of the electrolyte to the active material, and the lithium ion transmission tortuosity is difficult to reduce, so that the electrochemical performance of the battery is affected.
From the results of example 1 and comparative example 1, it is understood that the ion transport channel tortuosity in the electrode is high and the rate performance of the battery is poor without adding a porous ceramic material to the electrode. From the results of example 2 and comparative example 2, it is understood that when the ratio of the D90 particle diameter of the active material to the D90 particle diameter of the porous ceramic material is too small, the number of porous ceramic materials entering into the pores of the active material becomes small, thereby reducing the improvement effect thereof on the lithium ion transport channels.
As is clear from the results of example 6 and comparative examples 3 to 4, when the mass fraction of the porous ceramic material is too high, more ceramic material is difficult to enter the pores of the active material, blocking the electron transport channels, and seriously affecting the performance of the battery; when the mass fraction of the porous ceramic material is too high and the D90 particle diameter ratio of the active material to the porous ceramic material is too small, more ceramic material may block the electron transport channel and its improvement effect on the lithium ion transport channel is weak, resulting in poor performance of the battery.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.
Claims (10)
1. An electrode, characterized in that the electrode comprises a current collector and an active material layer arranged on the surface of the current collector, wherein the active material layer comprises an active material and a porous ceramic material;
the ratio of the D90 particle size of the active substance to the D90 particle size of the porous ceramic material is more than or equal to 8; the pore volume of the porous ceramic material is more than or equal to 0.1cm 3 /g；
And the mass fraction of the porous ceramic material added is less than or equal to 6 percent based on 100 percent of the mass of the electrode.
2. The electrode according to claim 1, wherein the active material is a positive electrode active material, and the porous ceramic material is added in an amount of 0.1 to 3% by mass based on 100% by mass of the electrode;
preferably, the ratio of the D90 particle diameter of the positive electrode active material to the D90 particle diameter of the porous ceramic material is 8 to 1000;
preferably, the D90 particle diameter of the positive electrode active material is 3 to 20 μm.
3. The electrode according to claim 1, wherein the active material is a negative electrode active material, and the porous ceramic material is added in an amount of 0.1 to 5% by mass based on 100% by mass of the electrode;
preferably, the ratio of the D90 particle diameter of the anode active material to the D90 particle diameter of the porous ceramic material is 28 to 1500;
preferably, the D90 particle diameter of the negative electrode active material is 10-30 μm.
4. An electrode according to any one of claims 1 to 3, wherein the porous ceramic material has a D90 particle size of 1 μm or less, preferably 500nm or less, more preferably 20 to 350nm.
5. The electrode of any one of claims 1-4, wherein the porous ceramic material has a pore volume of 0.12-1.50cm 3 /g；
Preferably, the specific surface area of the porous ceramic material is 10m or more 2 Preferably 20-800m 2 /g。
6. The electrode of any one of claims 1-5, wherein the porous ceramic material comprises porous primary particles and/or porous secondary particles;
preferably, the porous primary particles comprise porous ceramic particles and/or tubular porous ceramic material;
preferably, the porous ceramic particles comprise at least one of attapulgite, clinoptilolite, phillipsite and medical stone;
preferably, the tubular porous ceramic material comprises at least one of halloysite, chrysotile and imogolite;
preferably, the porous primary particles have a D90 particle diameter of 1 μm or less, preferably 500nm or less, and more preferably 20 to 350nm.
7. The electrode of claim 6, wherein the porous secondary particles comprise SiO 2 Porous secondary particles, tiO 2 Porous secondary particles and Al 2 O 3 At least one of the porous secondary particles;
preferably, the porous secondary particles are formed by combining primary particles;
preferably, the primary particles have a D90 particle size of 500nm or less, preferably 5 to 350nm;
preferably, the D90 particle size of the porous secondary particles is 500nm or less, preferably 20-350nm.
8. The electrode according to any one of claims 1 to 7, wherein the active material layer further comprises a binder and a conductive agent;
preferably, the conductive agent includes at least one of carbon nanotubes, vapor grown carbon fibers, and carbon black.
9. The electrode according to any one of claims 1 to 8, wherein the active material layer has a thickness of 10 to 100 μm;
preferably, the active material layer has a porosity of 20 to 40%.
10. A lithium ion battery, characterized in that it comprises an electrode according to any one of claims 1-9.
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| CN202310547331.6A CN116845246A (en) | 2023-05-16 | 2023-05-16 | Electrode and lithium ion battery |
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