CN117476937A - Poly (propylene carbonate) phthalate binder for dry electrode - Google Patents
Poly (propylene carbonate) phthalate binder for dry electrode Download PDFInfo
- Publication number
- CN117476937A CN117476937A CN202311377686.1A CN202311377686A CN117476937A CN 117476937 A CN117476937 A CN 117476937A CN 202311377686 A CN202311377686 A CN 202311377686A CN 117476937 A CN117476937 A CN 117476937A
- Authority
- CN
- China
- Prior art keywords
- phthalate
- binder
- ppc
- poly
- equal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000011230 binding agent Substances 0.000 title claims abstract description 42
- 229920000379 polypropylene carbonate Polymers 0.000 title claims description 22
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 title claims description 21
- -1 polypropylene carbonate phthalate Polymers 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 239000002482 conductive additive Substances 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 239000007774 positive electrode material Substances 0.000 claims description 9
- 238000007731 hot pressing Methods 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 239000005057 Hexamethylene diisocyanate Substances 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 claims description 6
- 238000000498 ball milling Methods 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 4
- 239000002041 carbon nanotube Substances 0.000 claims description 4
- 239000011888 foil Substances 0.000 claims description 4
- 238000000227 grinding Methods 0.000 claims description 4
- 239000012948 isocyanate Substances 0.000 claims description 4
- 150000002513 isocyanates Chemical class 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 claims description 3
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 claims description 3
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 2
- 239000004970 Chain extender Substances 0.000 claims description 2
- QXZUUHYBWMWJHK-UHFFFAOYSA-N [Co].[Ni] Chemical compound [Co].[Ni] QXZUUHYBWMWJHK-UHFFFAOYSA-N 0.000 claims description 2
- FDLZQPXZHIFURF-UHFFFAOYSA-N [O-2].[Ti+4].[Li+] Chemical compound [O-2].[Ti+4].[Li+] FDLZQPXZHIFURF-UHFFFAOYSA-N 0.000 claims description 2
- RLJDSHNOFWICBY-UHFFFAOYSA-N [P]=O.[Fe].[Li] Chemical compound [P]=O.[Fe].[Li] RLJDSHNOFWICBY-UHFFFAOYSA-N 0.000 claims description 2
- 239000006183 anode active material Substances 0.000 claims description 2
- 238000003490 calendering Methods 0.000 claims description 2
- 239000006229 carbon black Substances 0.000 claims description 2
- 239000004917 carbon fiber Substances 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 239000003273 ketjen black Substances 0.000 claims description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 claims description 2
- 229910002102 lithium manganese oxide Inorganic materials 0.000 claims description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 claims description 2
- VLXXBCXTUVRROQ-UHFFFAOYSA-N lithium;oxido-oxo-(oxomanganiooxy)manganese Chemical compound [Li+].[O-][Mn](=O)O[Mn]=O VLXXBCXTUVRROQ-UHFFFAOYSA-N 0.000 claims description 2
- URIIGZKXFBNRAU-UHFFFAOYSA-N lithium;oxonickel Chemical compound [Li].[Ni]=O URIIGZKXFBNRAU-UHFFFAOYSA-N 0.000 claims description 2
- 229910021392 nanocarbon Inorganic materials 0.000 claims description 2
- 239000013638 trimer Substances 0.000 claims description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 18
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 18
- 239000002904 solvent Substances 0.000 abstract description 14
- 125000005587 carbonate group Chemical group 0.000 abstract description 5
- 230000008569 process Effects 0.000 abstract description 5
- 238000002360 preparation method Methods 0.000 abstract description 4
- 230000001351 cycling effect Effects 0.000 abstract description 3
- 238000005265 energy consumption Methods 0.000 abstract description 3
- 238000013508 migration Methods 0.000 abstract description 3
- 230000005012 migration Effects 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 3
- 239000006057 Non-nutritive feed additive Substances 0.000 abstract description 2
- 238000012360 testing method Methods 0.000 description 19
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 14
- 239000003792 electrolyte Substances 0.000 description 11
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 9
- 239000002033 PVDF binder Substances 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 229920006238 degradable plastic Polymers 0.000 description 7
- 230000004913 activation Effects 0.000 description 6
- 239000001569 carbon dioxide Substances 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 5
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 4
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 4
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000002440 industrial waste Substances 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 229910010710 LiFePO Inorganic materials 0.000 description 2
- 229910013553 LiNO Inorganic materials 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006182 cathode active material Substances 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 description 2
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 2
- 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 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 description 1
- 238000000944 Soxhlet extraction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012662 bulk polymerization Methods 0.000 description 1
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 239000011267 electrode slurry Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003759 ester based solvent Substances 0.000 description 1
- 150000002148 esters Chemical group 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/16—Aliphatic-aromatic or araliphatic polycarbonates
- C08G64/1608—Aliphatic-aromatic or araliphatic polycarbonates saturated
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/42—Chemical after-treatment
-
- 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
Abstract
The invention discloses a polypropylene carbonate phthalate binder for dry electrodes. The invention discovers for the first time that PPC-P or PPC-P with a cross-linked structure can be used as a binder of a dry electrode, and the PPC-P has strong solvent resistance and good mechanical properties. The rich polar carbonate groups in PPC-P facilitate lithium ion migration, thus having higher ionic conductivity. Meanwhile, the PPC-P has good cohesiveness due to rich polar groups. The PPC-P binder is used in the dry electrode, so that the internal resistance of the battery can be effectively reduced, the cycling stability of the pole piece is improved, and the electrochemical performance of the battery is greatly improved. The invention adopts the solvent-free method to prepare the dry electrode, does not need a solvent removal process or adding a processing aid in the preparation process, can reduce the energy consumption and the cost for manufacturing the lithium ion battery, reduce the pollution to the environment and shorten the processing period.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a novel adhesive for a dry electrode.
Background
In recent years, with rapid updating of electronic products and rapid development and popularization of electric automobiles, lithium ion batteries are used as main energy sources, and performance needs to be further improved. Current research on lithium ion batteries is mainly focused on electrodes, electrolytes, separators and the like. The binder in the electrode has the characteristics of various types, small dosage, strong adhesiveness and the like. The binder used in the commercial lithium ion battery at present is mostly a polymer binder, and the binder is only a small part (usually 2-5%) of the electrode slurry component as an inactive component, but plays an important role in the formation of a uniform positive and negative electrolyte interface film (CEI/SEI film), the high-rate charge and discharge performance of the battery and the improvement of the long-cycle stability of the battery. The most commonly used commercial binder polyvinylidene fluoride (PVDF) is high in price, and in chemical property, PVDF has the problem of electrolyte swelling, and is easy to react with carbon-based materials to cause lithium salt to be deposited on a negative electrode, and the electronic conductivity and the ionic conductivity of the PVDF are poor, so that the electrochemical performance of a battery is influenced. At present, a solvent method is used for manufacturing the lithium ion battery pole piece, and a common solvent N-methylpyrrolidone (NMP) has certain toxicity, and the drying and other processes of solvent removal are high in cost, long in time consumption and can influence the environment.
The PPC-P degradable plastic is a resin product obtained by taking propylene oxide, phthalic anhydride and carbon dioxide block combination process technical scheme, taking CO2, PO and PA as raw materials and carrying out bulk polymerization under the action of a catalyst. The PPC-P degradable plastic is a novel environment-friendly material, and compared with PPC, the PPC-P degradable plastic has better mechanical property, heat resistance and high barrier property. According to the market depth investigation and development prospect prediction report of the China PPC-P degradable plastic industry published by the New Sitting industry research center, the PPC-P degradable plastic is carbon dioxide-based plastic, the PPC-P degradable plastic industry is developed, environmental pollution can be avoided, carbon dioxide recycling can be realized, and the market development prospect of the PPC-P degradable plastic is good.
However, polypropylene carbonate phthalate (PPC-P) has not been used as a binder for dry electrodes.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the polypropylene carbonate phthalate binder for the dry electrode, which has the advantages of electrolyte dissolution resistance, higher ionic conductivity, good cohesiveness, capability of effectively reducing the internal resistance of a battery and improving the cycle stability of a pole piece.
In order to achieve the above purpose, the invention adopts the following technical scheme:
through a large number of experiments, the invention discovers that the poly (propylene carbonate) phthalate (PPC-P) or the poly (propylene carbonate) phthalate with a cross-linked structure has good electrolyte dissolution resistance, higher ionic conductivity and good cohesiveness, can effectively reduce the internal resistance of a battery and improve the cycling stability of a pole piece. The structural formula of the polypropylene carbonate phthalate is shown in a formula (1), and the molecular weight is preferably more than 50 kDa.
Structure of Poly (propylene carbonate) phthalate of formula 1
Wherein a is more than or equal to 1, b is more than or equal to 1, c is more than or equal to 1, a, b and c are integers, the proportion of a section a is more than or equal to 30% of the total chain segment, and the proportion of b section b is more than or equal to 60% of the total chain segment;
the poly (propylene carbonate) phthalate with the cross-linked structure is prepared by blending poly (propylene carbonate) phthalate with the cross-linked structure by taking poly (propylene carbonate) phthalate as a raw material and isocyanate as a chain extender.
The isocyanate is preferably: toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene Diisocyanate (HDI), hexamethylene diisocyanate trimer, 4',4 "-Triphenylmethane Triisocyanate (TTI).
The typical structural formula of the polypropylene carbonate phthalate with the cross-linked structure is shown as a formula (2), and is called the cross-linked polypropylene carbonate phthalate for short, wherein the gel content of the polypropylene carbonate phthalate is more than 40%, a is more than or equal to 1, b is more than or equal to 1, c is more than or equal to 1, a, b and c are integers, the proportion of a section of the polypropylene carbonate phthalate is more than or equal to 30% of the total chain segment proportion, and the proportion of b section of the polypropylene carbonate phthalate is more than or equal to 60% of the total chain segment proportion; gel content refers to the percentage of the insoluble portion remaining after the sample is fully infiltrated by the corresponding good solvent to the mass of the original sample. The higher the gel content, the higher the crosslinking degree of the sample, and the stronger the solvent dissolution resistance of the sample; the lower the gel content, the lower the degree of crosslinking and the weaker the sample's resistance to solvent dissolution.
The adhesive for dry electrodes contains a poly (propylene carbonate) phthalate or a poly (propylene carbonate) phthalate having a crosslinked structure.
A dry electrode includes a positive electrode active material, a conductive additive, a binder, and a current collector; the positive electrode active material and the conductive additive are fixed on the current collector through a binder, wherein the binder is poly (propylene carbonate) phthalate or poly (propylene carbonate) phthalate with a cross-linked structure.
Preferably, in the dry electrode, the mass ratio of the positive electrode active material is 80% -98%, the mass ratio of the binder is 1% -10%, and the mass ratio of the conductive additive is 1% -10%; the current collector is aluminum foil, carbon-coated aluminum foil or aluminum net, the thickness of the current collector is 10-25 mu m, and the thickness of the positive pole piece is 80-500 mu m.
Preferably, in the above dry electrode, the positive electrode active material is: lithium nickel oxide, lithium cobalt oxide, lithium titanium oxide, lithium manganese oxide, lithium iron phosphorus oxide, or nickel cobalt multi-element oxide; the conductive additive is one or more of ketjen black, carbon black, conductive graphite, carbon nano tube or nano carbon fiber.
The preparation method of the dry electrode comprises the following steps: firstly, mixing and grinding an anode active material, a conductive additive and a binder in proportion, then adding the mixture into a planetary ball mill at room temperature, ball milling for 6-24 hours at the speed of 100-300 r/min to obtain uniformly mixed anode powder, calendering the anode powder on a current collector through a powder hot-pressing method, and hot-pressing the anode powder for 5-30 minutes through a hot press under the conditions of 6-10MPa and 100-200 ℃ to obtain the dry electrode anode.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention discovers for the first time that the PPC-P can be used as the binder of the dry electrode, and the PPC-P with a cross-linked structure have strong solvent resistance and good mechanical properties. The rich polar carbonate groups in PPC-P facilitate lithium ion migration, thus having higher ionic conductivity. Meanwhile, the PPC-P has good cohesiveness due to rich polar groups. The PPC-P binder is used in the dry electrode, so that the internal resistance of the battery can be effectively reduced, the cycling stability of the pole piece is improved, and the electrochemical performance of the battery is greatly improved.
(2) The invention adopts the solvent-free method to prepare the dry electrode, does not need a solvent removal process and does not need to add a processing aid in the preparation process, so that the energy consumption and the cost for manufacturing the lithium ion battery can be reduced, the processing period can be shortened, the carbon dioxide of industrial waste gas can be effectively utilized, and the pollution to the environment can be reduced.
Drawings
Fig. 1 is a charge-discharge curve of a lithium ion battery according to example 1 of the present invention.
Fig. 2 is a charge-discharge cycle comparison of lithium ion batteries of example 1, example 2 and comparative example 1 of the present invention.
Fig. 3 is a ratio performance comparison of lithium ion batteries of example 1 of the present invention and comparative example 1.
Fig. 4 is a charge-discharge curve of the lithium ion battery of example 3 of the present invention.
Fig. 5 is a ratio performance comparison of lithium ion batteries of example 3 of the present invention and comparative example 2.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making creative efforts based on the embodiments of the present invention are included in the protection scope of the present invention.
Poly (propylene carbonate) phthalate (PPC-P) is a high polymer material with good adhesive property, mechanical property and lithium ion conductivity, which is prepared by using industrial waste gas carbon dioxide as raw material. PPC-P has high tensile strength and satisfactory bonding effect on the premise of maintaining more polar carbonate groups. The abundant polar carbonate groups facilitate lithium ion migration, and thus have higher ionic conductivity. The PPC-P is used as an electrode binder, and the carbonate functional group and the ester functional group in the chain segment respectively have good compatibility with carbonate and ester solvents of electrolyte, so that the interface performance of the electrode can be better improved. The use of PPC-P with a crosslinked structure is better able to resist dissolution of the electrolyte. In addition, PPC-P has no melting point, can reach a flowing state at 150 ℃, and is very suitable for a solvent-free dry preparation process. The PPC-P is used as the binder of the lithium ion battery, and the battery pole piece is prepared by combining a solvent-free method, so that complicated technological processes such as drying and the like required by solvent removal are not needed, the manufacturing energy consumption and cost of the lithium ion battery can be reduced, the processing period is shortened, and the carbon dioxide of industrial waste gas is efficiently utilized and the pollution to the environment is reduced.
Example 1:
(1) Preparing a positive plate by a solvent-free method: lithium iron phosphate (LiFePO) as a cathode active material 4 ) Carbon-containing conductive additives (conductive carbon black and carbon nanotubes) and molecular weightMixing and grinding a 60kDa PPC-P binder according to a mass ratio of 88:2:8:2, adding the mixture into a planetary ball mill at room temperature, ball-milling the mixture for 20 hours at a speed of 100 revolutions per minute to obtain uniformly mixed positive electrode powder, rolling the positive electrode powder into sheets, hot-pressing the sheets by a manual hot press, and hot-pressing the sheets at 8MPa and 170 ℃ for 10 minutes to obtain a dry electrode positive electrode sheet;
(2) Under argon atmosphere, assembling the prepared dry electrode positive plate and the prepared negative electrode in a glove box to obtain 2032-type button cell, wherein the electrolyte contains 2% of LiNO 3 LiTFSI concentration of 1mol/L, and solvent of Dioxolane (DOL): ethylene glycol dimethyl ether (DME) =1:1 electrolyte.
(3) The charge and discharge test was performed at a current density of 0.1C using a constant current charge and discharge mode, and the results are shown in fig. 1. The initial specific charge capacity is 162.4mAh/g, the initial specific discharge capacity is 159.6mAh/g, and the initial coulombic efficiency is 98.3%.
(4) Using a constant current charge-discharge mode, after 3 turns of activation at a current density of 0.1C, a charge-discharge test was performed at a current density of 1C, and the test result was shown in fig. 2 under a condition that the discharge cut-off voltage was 2.4V and the charge cut-off voltage was 3.8V.
(5) To test the rate performance of example 1, charge and discharge tests were performed at 0.1c,0.2c,0.5c,1c,2c, and 0.1c rates in this order, and the test results are shown in fig. 3.
Comparative example 1:
(1) The PPC-P binder of example 1 was replaced with conventional PVDF as the binder, and otherwise the prepared pole piece loading was similar to that of example 1. (2) battery assembly was carried out in the same manner as in example 1.
(3) The charge and discharge test was performed at a current density of 1C using a constant current charge and discharge mode. The test results compared with example 1 are shown in fig. 2 under the condition that the discharge cut-off voltage is 2.4V and the charge cut-off voltage is 3.8V. The initial coulombic efficiency of the cell with PVDF as binder was lower (71.2%) than that of example 1, the specific discharge capacity after activation was low (96.3 mAh/g, the specific discharge capacity of example 1 was 132.8 mAh/g), and the capacity retention after 100 cycles was 94.2%, similar to example 1. (the capacity retention rate of example 1 was 93.8%). (4) To test the rate performance of comparative example 1, charge and discharge tests were performed at 0.1c,0.2c,0.5c,1c,2c, and 0.1c rates in this order, and the test results are shown in fig. 3. Compared with example 1, the discharge specific capacity of the battery with PVDF as the binder is lower than that of the battery with PPC-P as the binder under different multiplying powers, and the battery with PPC-P as the binder shows more excellent multiplying power performance.
Example 2:
(1) The PPC-P binder in example 1 was replaced with PPC-P having a molecular weight of 40kDa as a binder, and the prepared pole piece was similar in loading to that of example 1, except for example 1.
(2) Battery assembly was performed in the same manner as in example 1.
(3) The charge and discharge test was performed at a current density of 1C using a constant current charge and discharge mode. The test results compared with example 1 are shown in fig. 2 under the condition that the discharge cut-off voltage is 2.4V and the charge cut-off voltage is 3.8V. The initial coulombic efficiency of the cell with low molecular weight PPC-P as binder was lower (93.92%) than that of example 1, the specific discharge capacity after activation was low (103.2 mAh/g, the specific discharge capacity of example 1 was 132.8 mAh/g), and after 100 cycles, the specific discharge capacity (100.6 mAh/g) was still lower than that of example 1 (124.6 mAh/g). However, the battery having a low molecular weight PPC-P as a binder still has higher coulombic efficiency and specific discharge capacity after activation, compared with comparative example 1, which shows that PPC-P having a molecular weight of 40kDa can also be used as a binder, but PPC-P having a molecular weight of more than 50kDa is more effective.
Example 3:
(1) Synthesis of PPC-P with crosslinked structure: PPC-P having a molecular weight of 50kDa was reacted with 4,4' -Triphenylmethane Triisocyanate (TTI) and Hexamethylene Diisocyanate (HDI) according to 100:0.2: mixing at a mass ratio of 0.5, and blending for 20min at 150 ℃ and a rotating speed of 70rpm by using a torque rheometer to obtain the PPC-P with a cross-linked structure.
(2) Gel content test of PPC-P having a crosslinked structure: 2g of the sample is placed in a filter cartridge, the sample is repeatedly soaked in methylene dichloride (methylene dichloride is good solvent for PPC-P) at 160 ℃ by using a Soxhlet extraction device, the filter cartridge is taken out and dried after 24 hours, and the mass of the residual sample is 0.9g, so that the gel content of the crosslinked PPC-P is 45%.
(3) Preparing a positive plate by a solvent-free method: lithium iron phosphate (LiFePO) as a cathode active material 4 ) Mixing and grinding carbon-containing conductive additive (conductive carbon black and carbon nano tube) and cross-linked PPC-P binder according to a mass ratio of 88:2:8:2, adding into a planetary ball mill at room temperature, ball milling for 8 hours at a speed of 280 revolutions per minute to obtain uniformly mixed positive electrode powder, rolling the positive electrode powder into sheets, hot-pressing by a manual hot press, and hot-pressing for 10 minutes under the conditions of 8MPa and 170 ℃ to obtain a dry electrode positive electrode sheet;
(4) Under argon atmosphere, assembling the prepared dry electrode positive plate and the prepared negative electrode in a glove box to obtain 2032-type button cell, wherein the electrolyte contains 2% of LiNO 3 LiTFSI concentration of 1mol/L, and solvent of Dioxolane (DOL): ethylene glycol dimethyl ether (DME) =1:1 electrolyte.
(5) The charge and discharge test was performed at a current density of 0.1C using a constant current charge and discharge mode, and the results are shown in fig. 4. The initial specific charge capacity is 161.3mAh/g, the initial specific discharge capacity is 159.3mAh/g, and the initial coulombic efficiency is 98.8%.
(6) Using a constant current charge-discharge mode, after 3 turns of activation at a current density of 0.1C, a charge-discharge test was performed at a current density of 1C, and the test result was shown in fig. 5 under a condition that the discharge cut-off voltage was 2.4V and the charge cut-off voltage was 3.8V.
Comparative example 2:
(1) The crosslinked PPC-P binder in example 3 was replaced with conventional PVDF as binder, and the prepared pole piece loading was similar to that of example 3, except that in example 3.
(2) Battery assembly was performed in the same manner as in example 3.
(3) The charge and discharge test was performed at a current density of 1C using a constant current charge and discharge mode. The test results of example 3 are compared with those of example 5 under the condition that the discharge cut-off voltage is 2.4V and the charge cut-off voltage is 3.8V. The initial coulombic efficiency of the pvdf-based binder cell was lower (95.1%) than that of example 3, the specific discharge capacity after activation was low (125.8 mAh/g, the specific discharge capacity of example 3 was 147.1 mAh/g), and after 100 cycles, the specific discharge capacity (125.1 mAh/g) was still lower than that of example 3 (127.2 mAh/g).
Claims (10)
1. Use of a poly (propylene carbonate) phthalate or a poly (propylene carbonate) phthalate having a crosslinked structure as a binder for dry electrodes.
2. The use according to claim 1, wherein the structural formula of the polypropylene carbonate phthalate is shown as formula (1), the molecular weight of the polypropylene carbonate phthalate is more than 50kDa, wherein a is more than or equal to 1, b is more than or equal to 1, c is more than or equal to 1, a, b and c are integers, the section a accounts for more than or equal to 30% of the total chain segment proportion, and the section b accounts for more than or equal to 60% of the total chain segment proportion;
the structure of the poly (propylene carbonate) phthalate of formula 1.
3. The use according to claim 1, wherein the polypropylene carbonate phthalate with a cross-linked structure is a polypropylene carbonate phthalate with a cross-linked structure which is obtained by blending polypropylene carbonate phthalate with an isocyanate as a chain extender.
4. The use according to claim 1, wherein the isocyanate is: toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate trimer, 4',4 "-triphenylmethane triisocyanate.
5. The application of claim 2, wherein the typical structural formula of the poly (propylene carbonate) phthalate with the cross-linked structure is shown as a formula (2), and is called cross-linked poly (propylene carbonate) phthalate for short, the gel content of the poly (propylene carbonate) phthalate is more than 40%, wherein a is more than or equal to 1, b is more than or equal to 1, c is more than or equal to 1, a, b and c are integers, the proportion of a segment is more than or equal to 30% of the total segment, and the proportion of b segment is more than or equal to 60% of the total segment;
the structure of the crosslinked polypropylene carbonate phthalate of formula 2.
6. A binder for dry electrodes, characterized by containing a polypropylene carbonate phthalate or a polypropylene carbonate phthalate having a crosslinked structure.
7. A dry electrode includes a positive electrode active material, a conductive additive, a binder, and a current collector; the positive electrode active material and the conductive additive are fixed on the current collector through a binder, and the positive electrode active material and the conductive additive are characterized in that the binder is poly (propylene carbonate) phthalate or poly (propylene carbonate) phthalate with a cross-linked structure.
8. The dry electrode of claim 7, wherein the positive electrode active material has a mass ratio of 80% to 98%, the binder has a mass ratio of 1% to 10%, and the conductive additive has a mass ratio of 1% to 10%; the current collector is aluminum foil, carbon-coated aluminum foil or aluminum net, the thickness of the current collector is 10-25 mu m, and the thickness of the positive pole piece is 80-500 mu m.
9. The dry electrode of claim 7, wherein the positive electrode active material is: lithium nickel oxide, lithium cobalt oxide, lithium titanium oxide, lithium manganese oxide, lithium iron phosphorus oxide, or nickel cobalt multi-element oxide; the conductive additive is one or more of ketjen black, carbon black, conductive graphite, carbon nano tube or nano carbon fiber.
10. The method for manufacturing a dry electrode according to claim 7, comprising the steps of: firstly, mixing and grinding an anode active material, a conductive additive and a binder in proportion, then adding the mixture into a planetary ball mill at room temperature, ball milling for 6-24 hours at the speed of 100-300 r/min to obtain uniformly mixed anode powder, calendering the anode powder on a current collector through a powder hot-pressing method, and hot-pressing the anode powder for 5-30 minutes through a hot press under the conditions of 6-10MPa and 100-200 ℃ to obtain the dry electrode anode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311377686.1A CN117476937A (en) | 2023-10-24 | 2023-10-24 | Poly (propylene carbonate) phthalate binder for dry electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311377686.1A CN117476937A (en) | 2023-10-24 | 2023-10-24 | Poly (propylene carbonate) phthalate binder for dry electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117476937A true CN117476937A (en) | 2024-01-30 |
Family
ID=89632339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311377686.1A Pending CN117476937A (en) | 2023-10-24 | 2023-10-24 | Poly (propylene carbonate) phthalate binder for dry electrode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117476937A (en) |
-
2023
- 2023-10-24 CN CN202311377686.1A patent/CN117476937A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109119592B (en) | Lithium titanate negative electrode piece, preparation method and lithium titanate battery | |
| CN111725559B (en) | Solid electrolyte, method for preparing the same, and lithium secondary solid battery | |
| CN111430716B (en) | Water-based soy protein-based supermolecule sulfur positive electrode binder and preparation method and application thereof | |
| CN110627997A (en) | Thermoplastic polyurethane adhesive for lithium ion battery and preparation method and application thereof | |
| CN110890545A (en) | PEDOT (polyethylene glycol terephthalate)/PSS (Polybutylece terephthalate)/CMC (carboxymethyl cellulose) composite binder as well as preparation method and application thereof | |
| CN105703003A (en) | Comb-shaped polymer, electrolyte and composite electrode for lithium battery, and applications of electrolyte and composite electrode | |
| CN111697231B (en) | Natural aqueous sulfur positive electrode binder, preparation method thereof and application of binder in preparation of sulfur positive electrode of lithium-sulfur battery | |
| CN111786017B (en) | High-cohesiveness solid electrolyte prepared by in-situ curing, preparation method and application | |
| CN116332152A (en) | Bagasse hard carbon-based anode material with sodium ion battery core-shell structure and preparation method thereof | |
| CN112615006A (en) | Preparation method of high-performance composite binder for energy storage charging system battery | |
| CN114171736B (en) | Water-based lithium manganate positive electrode slurry and preparation method thereof | |
| CN112563483A (en) | Positive active material slurry of lithium ion battery and preparation method | |
| CN107834072B (en) | Lithium ion battery binder | |
| CN113299918B (en) | Negative pole piece and lithium ion battery comprising same | |
| CN113363482B (en) | Composite binder for silicon-based negative electrode of lithium ion battery and preparation method and application thereof | |
| CN117476937A (en) | Poly (propylene carbonate) phthalate binder for dry electrode | |
| CN111628167A (en) | Preparation method of lithium iron phosphate anode slurry for lithium ion battery | |
| CN117894990A (en) | Silicon-based negative electrode water-based binder and preparation method and application thereof | |
| CN111697234B (en) | Water-based crosslinking binder for lithium ion battery and preparation method and application thereof | |
| CN114220952B (en) | Electrode material for reducing volume change of electrode in charging and discharging processes and battery | |
| CN116613296B (en) | Silicon-carbon negative electrode material of lithium ion battery, and preparation method and application thereof | |
| CN116666610B (en) | Silicon-carbon negative electrode material and preparation method and application thereof | |
| CN115000342B (en) | Lithium-sulfur battery positive electrode with double-capture function, and preparation method and application thereof | |
| CN116845237A (en) | Adhesive for lithium ion battery, battery pole piece and preparation method of battery pole piece | |
| CN115849366A (en) | High-energy quick-charging graphite material for power battery and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |