CN114806171B - Dispersing agent of conductive agent and application thereof - Google Patents
Dispersing agent of conductive agent and application thereof Download PDFInfo
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- CN114806171B CN114806171B CN202210567162.8A CN202210567162A CN114806171B CN 114806171 B CN114806171 B CN 114806171B CN 202210567162 A CN202210567162 A CN 202210567162A CN 114806171 B CN114806171 B CN 114806171B
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- 239000006258 conductive agent Substances 0.000 title claims abstract description 55
- 239000002270 dispersing agent Substances 0.000 title claims abstract description 55
- 229920002959 polymer blend Polymers 0.000 claims abstract description 22
- 239000000463 material Substances 0.000 claims abstract description 20
- 238000010521 absorption reaction Methods 0.000 claims abstract description 13
- 125000003118 aryl group Chemical group 0.000 claims abstract description 13
- 125000004093 cyano group Chemical group *C#N 0.000 claims abstract description 13
- 125000005462 imide group Chemical group 0.000 claims abstract description 11
- 239000002861 polymer material Substances 0.000 claims abstract description 11
- 229920000642 polymer Polymers 0.000 claims description 35
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 16
- 239000004642 Polyimide Substances 0.000 claims description 10
- 229920001721 polyimide Polymers 0.000 claims description 10
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 8
- 229920002285 poly(styrene-co-acrylonitrile) Polymers 0.000 claims description 7
- 239000000178 monomer Substances 0.000 claims description 5
- 230000000694 effects Effects 0.000 abstract description 9
- 230000000052 comparative effect Effects 0.000 description 10
- 239000011267 electrode slurry Substances 0.000 description 10
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 8
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 8
- CFEYBLWMNFZOPB-UHFFFAOYSA-N Allylacetonitrile Natural products C=CCCC#N CFEYBLWMNFZOPB-UHFFFAOYSA-N 0.000 description 6
- SJNALLRHIVGIBI-UHFFFAOYSA-N allyl cyanide Chemical compound C=CCC#N SJNALLRHIVGIBI-UHFFFAOYSA-N 0.000 description 6
- 230000014759 maintenance of location Effects 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 4
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 4
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000002329 infrared spectrum Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229930015698 phenylpropene Natural products 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- HJWLCRVIBGQPNF-UHFFFAOYSA-N prop-2-enylbenzene Chemical compound C=CCC1=CC=CC=C1 HJWLCRVIBGQPNF-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- UVKXJAUUKPDDNW-NSCUHMNNSA-N (e)-pent-3-enenitrile Chemical compound C\C=C\CC#N UVKXJAUUKPDDNW-NSCUHMNNSA-N 0.000 description 2
- JLBJTVDPSNHSKJ-UHFFFAOYSA-N 4-Methylstyrene Chemical compound CC1=CC=C(C=C)C=C1 JLBJTVDPSNHSKJ-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- PBGVMIDTGGTBFS-UHFFFAOYSA-N but-3-enylbenzene Chemical compound C=CCCC1=CC=CC=C1 PBGVMIDTGGTBFS-UHFFFAOYSA-N 0.000 description 2
- CREMABGTGYGIQB-UHFFFAOYSA-N carbon carbon Chemical compound C.C CREMABGTGYGIQB-UHFFFAOYSA-N 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 150000002430 hydrocarbons Chemical group 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- -1 nitrile compounds Chemical class 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 241000872198 Serjania polyphylla Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000002003 electrode paste Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 150000003384 small molecules Chemical group 0.000 description 1
- 230000003335 steric effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
- C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/20—Applications use in electrical or conductive gadgets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a dispersant of a conductive agent and application thereof, wherein the dispersant of the conductive agent is a polymer blend material, and the polymer blend material comprises cyano groups, aromatic groups and imide groups; the infrared absorption peaks of the blended polymer material include: 2100cm ‑1 Up to 2400cm ‑1 、1650cm ‑1 To 1690cm ‑1 And 1500cm ‑1 To 1690cm ‑1 . The dispersing agent containing the group with the specific infrared absorption peak is used as a dispersing agent of the conductive agent, has a good dispersing effect, can be used under high voltage, can reduce the volume change of the electrode plate, and greatly improves the cycle performance of the battery under high voltage.
Description
Technical Field
The invention belongs to the technical field of batteries, and relates to a dispersing agent, in particular to a dispersing agent of a conductive agent and application thereof.
Background
When the battery pole piece is prepared, conductive agents such as conductive carbon black or acetylene black with smaller particles are added into the electrode slurry, and large particles are formed in the electrode slurry by the conductive agents, so that the conductive agents are obviously unevenly dispersed in the electrode slurry, on one hand, the stability and rheological property of the electrode slurry are affected, on the other hand, the conductive agents on the pole piece are unevenly distributed, and the prepared battery pole piece has the problems of uneven conductivity, large resistivity change and the like.
The dispersing agent of the conductive agent in the existing battery is PVP (polyvinylpyrrolidone, K30 model), and in a high-voltage system of 4.4V or even 5V, PVP is unstable due to the fact that the structure of the PVP is five-membered ring, PVP can be decomposed in an open loop under the high-temperature and high-voltage condition, and the original complete conductive network is damaged, so that the battery is attenuated in a circulating acceleration way.
Based on the above research, it is necessary to provide a dispersant for a conductive agent, which has a good dispersing effect on the conductive agent and can be used under high voltage, thereby improving the cycle performance of the battery and making the conductivity distribution of the pole pieces uniform.
Disclosure of Invention
The invention aims to provide a dispersant of a conductive agent and application thereof, wherein the dispersant contains cyano groups, aromatic groups and imide groups, so that the dispersibility of the conductive agent in electrode slurry can be improved, the expansion and contraction of an electrode plate can be reduced, and the dispersant has higher stability and can be used under high voltage.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a dispersant for a conductive agent that is a blended polymeric material comprising cyano groups, aromatic groups, and imide groups;
the infrared absorption peaks of the blended polymer material include: 2100cm -1 Up to 2400cm -1 、1650cm -1 To 1690cm -1 And 1500cm -1 To 1690cm -1 。
The dispersing agent is higher in dispersion aiming at the conductive agent, and the aromatic groups contained in the dispersing agent can prevent aggregation of the conductive agent through steric effect, so that electron clouds of benzene rings in the aromatic groups can achieve pi-pi effect on the surface of the conductive agent, and the dispersibility of the conductive agent is further improved; the cyano group can enable the dispersant to be used in a high-voltage environment, so that the problem of excessively fast decay of battery cycle performance under high voltage is avoided; the imide group contained in the dispersant can resist the expansion and contraction of the electrode, and at the same time, can be well dispersed as a polar group in a solvent used for the electrode paste.
The infrared absorption peak of the invention is 2100cm -1 Up to 2400cm -1 A stretching vibration peak corresponding to cyano group in a range of 1650cm -1 To 1690cm -1 The range corresponds to the stretching vibration peak of aromatic group, at 1500cm -1 To 1690cm -1 The range corresponds to the stretching vibration peak of imide group.
Preferably, the blended polymeric material further comprises hydrocarbon chain groups.
The dispersant also contains hydrocarbon chain groups, so that the dispersant can be well compatible with a conductive agent such as a carbon material or a carbon-coated material, and the dispersibility of the dispersant on the conductive agent is better.
Preferably, the blended polymer material further comprises carbonyl groups, corresponding to an infrared absorption peak of 1650cm -1 To 1900cm -1 Also comprises carbon-carbon double bond, and has an infrared absorption peak of 3000cm -1 To 3100cm -1 。
Preferably, the weight average molecular weight of the polymer blend material is 10000 or less, for example 10000, 9000, 8000, 7000, 6000, 5000, 4000 or 3000, but not limited to the values recited, other non-recited values within the range of values are equally applicable, preferably 4000 to 10000.
The dispersing agent of the conductive agent is a small-molecule polymer blend, so that the compactness of a conductive network formed by the conductive agent in the electrode plate is prevented from being reduced when the molecular weight is too high, the molecular weight is controlled to be less than 10000, the dispersibility of the conductive agent can be ensured, and the compactness and the integrity of the conductive network can be ensured.
Preferably, the blended polymer material comprises polymer a and polymer B, the polymer a comprising polyimide.
The polyimide has the following structural formula:
preferably, the polymer B includes a polymer containing an aromatic ring and a cyano group.
Preferably, the molar ratio of polymer A to polymer B is (1.2 to 1.8): 0.2, which may be, for example, 1.2:0.2, 1.3:0.2, 1.4:0.2, 1.5:0.2, 1.6:0.2, 1.7:0.2 or 1.8:0.2, but is not limited to the recited values, as other non-recited values within the range of values are equally applicable.
Preferably, the monomers of the polymer B comprise phenyl-containing olefins and nitrile compounds containing carbon-carbon unsaturated bonds in a molar ratio of (0.2 to 0.7): 1, which may be, for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1 or 0.7:1, but are not limited to the values recited, other non-recited values within the range of values being equally applicable.
The content of each group which plays a role is controlled, and the blend polymer material can achieve the optimal dispersing effect through the synergistic effect among the groups.
Preferably, the phenyl-containing olefin comprises any one or a combination of at least two of styrene, allylbenzene, methyl styrene or 4-phenyl-1-butene, typically but not limited to a combination comprising styrene and allylbenzene, a combination of allylbenzene and methyl styrene, or a combination of 4-phenyl-1-butene and styrene, preferably styrene.
Preferably, the nitrile compound containing carbon-carbon unsaturation comprises any one or a combination of at least two of acrylonitrile, 3-butenenitrile, 3-pentenenitrile, or 4-pentenenitrile, and typical but non-limiting combinations include combinations of acrylonitrile and 3-butenenitrile, combinations of 3-butenenitrile and 3-pentenenitrile, or combinations of 4-pentenenitrile and acrylonitrile, preferably acrylonitrile.
Preferably, the polymer blend comprises a polyimide and a styrene-acrylonitrile copolymer.
The dispersing agent of the conductive agent is preferably a blend of polyimide and a styrene-acrylonitrile copolymer, can be used under high voltage, can overcome the problem that PVP dispersing agent is ring-opened under high voltage to lower the cycle performance of a battery, has higher dispersibility on the conductive agent than other substances, can reduce the volume change of an electrode plate, and has better dispersibility in NMP (N-methylpyrrolidone) which is a common solvent for preparing electrode slurry.
In a second aspect, the present invention provides an electrode sheet comprising a dispersant for the conductive agent of the first aspect.
The electrode plate comprises a positive plate and/or a negative plate.
In a third aspect, the present invention provides an electrochemical device comprising a battery pole piece as described in the second aspect.
Compared with the prior art, the invention has the following beneficial effects:
the invention adopts the polymer blend containing cyano groups, aromatic groups and imide groups and having absorption peaks in a specific infrared range as the dispersing agent of the conductive agent, not only has pertinence to the dispersion of the conductive agent compared with other substances, but also can be used under high voltage, and the agglomeration of the conductive agent is mainly prevented by the groups such as benzene rings with larger steric hindrance in the polymer blend, and the like, and the volume change of the electrode pole piece can be reduced, the cycle performance of the battery under high voltage is greatly improved, the uniformity of the conductivity of the electrode pole piece at all positions is improved, and meanwhile, the smaller molecular weight ensures the integrity and compactness of a conductive network in the electrode pole piece.
Drawings
FIG. 1 is a graph showing the cycle number versus capacity retention of batteries to which the dispersants of example 1 and comparative example 1 of the present invention are applied.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides a dispersant of a conductive agent, wherein the dispersant of the conductive agent is a polymer blend material, and the polymer blend material comprises cyano groups, aromatic groups and imide groups; the infrared absorption peak ranges of the blended polymer material include: 2100cm -1 Up to 2400cm -1 、1650cm -1 To 1690cm -1 And 1500cm -1 To 1690cm -1 ；
The weight average molecular weight of the polymer blend material is 8000, the polymer blend material comprises a polymer A and a polymer B, and the molar ratio of the polymer A to the polymer B is 1.5:0.2; the polymer A is polyimide;
the polymer B is a styrene-acrylonitrile copolymer, and the monomers comprise styrene and acrylonitrile in a molar ratio of 0.5:1;
the relationship between the cycle number and the capacity retention rate of the battery to which the dispersant of this example was applied is shown in fig. 1.
Example 2
The embodiment provides a dispersant of a conductive agent, wherein the dispersant of the conductive agent is a polymer blend material, and the polymer blend material comprises cyano groups, aromatic groups and imide groups; the infrared absorption peak ranges of the blended polymer material include: 2100cm -1 Up to 2400cm -1 、1650cm -1 To 1690cm -1 And 1500cm -1 To 1690cm -1 ；
The weight average molecular weight of the polymer blend material is 10000, the polymer blend material comprises a polymer A and a polymer B, and the molar ratio of the polymer A to the polymer B is 1.2:0.2; the polymer A is polyimide;
the polymer B is a styrene-acrylonitrile copolymer, and the monomers comprise styrene and acrylonitrile in a molar ratio of 0.7:1.
Example 3
The embodiment provides a dispersant of a conductive agent, wherein the dispersant of the conductive agent is a polymer blend material, and the polymer blend material comprises cyano groups, aromatic groups and imide groups; the infrared absorption peak ranges of the blended polymer material include: 2100cm -1 Up to 2400cm -1 、1650cm -1 To 1690cm -1 And 1500cm -1 To 1690cm -1 ；
The weight average molecular weight of the polymer blend material is 3000, the polymer blend material comprises a polymer A and a polymer B, and the molar ratio of the polymer A to the polymer B is 1.8:0.2; the polymer A is polyimide;
the polymer B is a styrene-acrylonitrile copolymer, and the monomers comprise styrene and acrylonitrile in a molar ratio of 0.2:1.
Examples 4 and 5 provide a dispersant for a conductive agent, which is the same as example 1 except for the change in weight average molecular weight, as shown in table 2.
Examples 6 and 7 provide a dispersant for a conductive agent, which is the same as example 1 except that the molar ratio of polymer a to polymer B is changed as shown in table 3.
Examples 8 and 9 provide a dispersant for a conductive agent, as shown in Table 4, which is the same as example 1 except that the kind of polymer B is changed.
Comparative example 1 provides a dispersant of a conductive agent, which is PVP (model: K30) as shown in Table 5, and a graph of the cycle number versus the capacity retention ratio of a battery to which the dispersant of this comparative example is applied is shown in FIG. 1.
Comparative example 2 provides a dispersant of a conductive agent, which is the same as example 1 except that the polymer B is polystyrene, as shown in table 5.
Performance test:
the dispersing agents of the conductive agents provided in the above examples and comparative examples are added to the positive electrode slurry and the negative electrode slurry respectively during the homogenization process, the positive electrode slurry is coated on an aluminum foil, the negative electrode slurry is coated on a copper foil, the positive electrode sheet and the negative electrode sheet are obtained after drying and cutting, and the positive electrode sheet, the negative electrode sheet, the Celgard2500 diaphragm and the electrolyte containing LiPF 6 Is assembled into a lithium ion battery.
The pole piece obtained by disassembling the lithium ion battery is soaked in DMC for 24 hours, dried for 2 hours in a blast oven at 60-80 ℃, scraped by a ceramic knife to obtain at least 1g of positive pole piece powder, 1g of powder and 1g of potassium bromide powder are mixed for 10-30 minutes by a mortar, and then put into the blast oven for drying at 40-60 ℃ for 1-2 hours, and the mixed sample is utilizedTabletting with a die to obtain an infrared sample, placing the sample in an infrared spectrum analyzer, wherein the infrared spectrum does not show peaks on inorganic substances, the sample contains a dispersing agent of a conductive agent, and the infrared is tested at 1500-1690cm respectively -1 、1650-1690-cm -1 And 2100-2400cm -1 Has an absorption peak.
The cyclic capacity retention test method comprises the following steps: at 25℃the cycle was carried out in a charge-discharge system of 0.19A/g (calculated as mass of positive electrode material). After cycling to 550 weeks, dividing the discharge capacity of the battery at the moment by the discharge capacity of the first cycle, namely the 550-cycle capacity retention rate of the battery.
Pole piece resistivity test: taking a head piece and a tail piece of a pole piece, cutting the pole piece into small wafers with the diameter of 14mm, and adopting a Hitachi resistance meter, wherein the equipment is of the type: RM9003, performing pole piece volume resistivity test.
The test results are shown in the following table:
TABLE 1
| 550 cycle capacity retention (%) | Pole piece resistivity range (omega cm) | |
| Example 1 | 84.9 | 14.2-15.3 |
| Example 2 | 84.4 | 16.4-18.2 |
| Example 3 | 83.9 | 16.9-20.1 |
TABLE 2
TABLE 3 Table 3
TABLE 4 Table 4
TABLE 5
From the above table, the following points can be seen:
(1) As can be seen from examples 1 to 9 and comparative examples 1 to 2, the dispersant of the conductive agent provided by the invention has a good dispersing effect, so that the conductivity of each part of the pole piece is uniform, the difference of the resistivity of each part of the pole piece is small, and the conductive agent has good cycle performance; as is clear from examples 1, 4 and 5, when the molecular weight of the dispersant is too large, the dispersing effect of the conductive agent and the distribution of the conductive network are affected; as is clear from examples 1, 6 and 7, the dispersion effect of the dispersant is affected when the content of each group is changed; from examples 1, 8 and 9, the preferred dispersants of the present invention are polymer blends of polyimide and styrene-acrylonitrile copolymers which allow the polymer blends to achieve optimal dispersion by synergy between the groups.
(2) As can be seen from example 1, comparative example 1 and comparative example 2, the dispersant provided by the invention can overcome the defect of the conventional conductive agent dispersant PVP, has a good dispersing effect, can be used under high voltage, and has lower capacity attenuation after multiple cycles than that of comparative example 1; from example 1 and comparative example 2, it is understood that the dispersant does not include cyano groups, but is merely a blend of polyimide and polystyrene, which has reduced compatibility with a conductive agent material on the one hand and cycle performance on the other hand.
In summary, the present invention provides a dispersant for a conductive agent, which contains cyano groups, aromatic groups and imide groups, and contains specific absorption peaks in the infrared spectrum, so that the dispersant has a good dispersing effect on the conductive agent, and can be used under high voltage, thereby improving the cycle performance of a battery and making the conductivity distribution of a pole piece uniform.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that fall within the technical scope of the present invention disclosed herein are within the scope of the present invention.
Claims (4)
1. A dispersant for a conductive agent, wherein the dispersant for the conductive agent is a blended polymer material comprising cyano groups, aromatic groups, and imide groups;
the infrared absorption peaks of the blended polymer material include: 2100cm -1 Up to 2400cm -1 、1650cm -1 To 1690cm -1 And 1500cm -1 To 1690cm -1 ；
The weight average molecular weight of the polymer blend material is less than 10000;
the blended polymer material comprises a polymer a comprising a polyimide and a polymer B comprising a styrene-acrylonitrile copolymer;
the molar ratio of the polymer A to the polymer B is (1.2 to 1.8): 0.2.
2. The dispersant for conductive agents according to claim 1, wherein the monomers of the polymer B comprise styrene and acrylonitrile in a molar ratio of (0.2 to 0.7): 1.
3. A battery pole piece, characterized in that it comprises a dispersant of the conductive agent according to claim 1 or 2.
4. An electrochemical device comprising the battery pole piece of claim 3.
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| JP2013036021A (en) * | 2011-07-08 | 2013-02-21 | Ube Industries Ltd | Carbon nanotube dispersant including polyamic acid |
| CN107408703A (en) * | 2015-03-06 | 2017-11-28 | 宇部兴产株式会社 | Electric conductivity aromatic polyimide perforated membrane and preparation method thereof |
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