CN116004150A - Polymer adhesive, positive electrode slurry and preparation method thereof - Google Patents

Abstract

The invention provides a polymer adhesive, positive electrode slurry and a preparation method thereof, belonging to the technical field of lithium battery manufacturing. The polymeric binder includes: an aqueous solution of polyethylene oxide and an aqueous solution of an acrylic acid ester multipolymer; wherein the polymer adhesive is a complex formed by complexing carboxyl in the acrylic ester multipolymer and ether oxygen sharing electron pair of polyethylene oxide. The polymer adhesive provided by the invention is used as a water-based adhesive, meets the requirements of green low cost, can improve the low-temperature performance of the battery, and provides a new raw material, path and method for preparing the lithium ion battery.

Description

A polymer binder, positive electrode slurry and preparation method thereof

technical field

The invention belongs to the technical field of lithium battery manufacturing and utilization, and in particular relates to a polymer binder, positive electrode slurry and a preparation method thereof.

Background technique

Lithium-ion battery is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. Lithium battery cathode material is a part of the lithium-ion battery constituent materials, which directly affects the performance of lithium-ion batteries and occupies a large proportion (the mass ratio of positive and negative electrode materials is 3::1~4:1).

In the positive electrode slurry prepared by the existing lithium ion positive electrode materials, the binder is mostly polyvinylidene fluoride binder, and its solution N-methylpyrrolidone is not only a toxic liquid that pollutes the environment but also is expensive.

The use of polyvinylidene fluoride binder has the following problems: Young's modulus is relatively high, between 1-4GPa, the flexibility of the pole piece is not good enough; after polyvinylidene fluoride absorbs water, the molecular weight decreases, and the viscosity becomes worse, which is harmful to the environment. The humidity requirement is relatively high; polyvinylidene fluoride is insulated to ions and electronics, has a certain degree of swelling in the electrolyte, and has an exothermic reaction with metal lithium and LixC6 at a relatively high temperature, which is not conducive to battery safety. In addition, the low-temperature discharge performance of existing oil-based batteries is poor, and the discharge capacity is very low under low-temperature conditions, which is difficult to meet the use requirements under low-temperature conditions.

Contents of the invention

In order to solve the above problems, the present invention provides a polymer adhesive, comprising: an aqueous solution of polyethylene oxide and an aqueous solution of acrylate multi-polymer;

Wherein, the polymer adhesive is a complex formed by complexing the carboxyl group in the acrylate multi-polymer and the ether oxygen of polyethylene oxide to share electron pairs;

Preferably, in the polymer adhesive, the mass ratio of polyethylene oxide and acrylate multi-polymer is 1:(0.01-100).

Preferably, in the aqueous solution of polyethylene oxide, the molecular weight of polyethylene oxide is 1×10 ³ -1×10 ⁹ .

Preferably, in the aqueous solution of polyethylene oxide, the mass fraction of polyethylene oxide is 0.01%-15%.

In addition, in order to solve the above problems, the present invention also provides a positive electrode slurry, including: positive electrode material, conductive agent, binder and solvent;

Wherein, the adhesive is a polymer adhesive as described above;

The ratio of the positive electrode material, the conductive agent and the binder is: (90-98):(0.01-10):(0.01-10).

Preferably, the positive electrode material includes one or more of commonly used positive electrode materials such as lithium iron phosphate, lithium manganate, lithium cobaltate, sodium vanadium phosphate, sodium manganate, and sodium iron pyrophosphate.

Preferably, the conductive agent material includes: one of SP, acetylene black, 350G, carbon fiber, carbon nanotube, Ketjen black, KS-6, KS-15, SFG-6, SFG-15, graphene or Several kinds.

In addition, in order to solve the above problems, the present invention also provides a method for preparing a polymer adhesive as described above, including:

Add polyethylene oxide particles into deionized water, and mix to obtain polyethylene oxide aqueous solution;

Take the acrylate multi-polymer, configure it into an aqueous solution of the acrylate multi-polymer, and add it to the polyethylene oxide aqueous solution;

Stirring and mixing under vacuum for 0.2-2 hours to obtain a polymer adhesive;

Preferably, the stirring and mixing time under vacuum is 0.5-1 hour.

Preferably, the mass fraction of the polyethylene oxide aqueous solution is 0.01% to 15%;

The mass fraction of the aqueous solution of the acrylate multi-polymer is 1% to 20%;

Preferably, the mass fraction of the polyethylene oxide aqueous solution is 2.0%-2.5%.

In addition, in order to solve the above problems, the present invention also provides a method for preparing positive electrode slurry as described above, including:

Add the conductive agent to the aqueous binder solution, stir and disperse for 0.5 hours to 2 hours to obtain a conductive solution;

Take the positive electrode material and add it to the conductive solution, first perform low-speed stirring at 5rpm-15rpm for 5 minutes-15 minutes, then perform high-speed stirring at 25rpm-35rpm for 0.5 hours-2 hours, after stirring and mixing, add deionized water for stirring and dispersed to obtain the positive electrode slurry;

Preferably, the time for high-speed stirring is 0.8 hour-1 hour.

Preferably, when adding deionized water for stirring and dispersing, the viscosity of the positive electrode slurry is adjusted to 3000mPa·s-7000mPa·s, and the solid content is 35%-80%;

Preferably, the positive electrode slurry has a viscosity of 4500mPa·s-5500mPa·s, and a solid content of 55%-58%.

The invention provides a polymer binder, positive electrode slurry and a preparation method thereof. Wherein the polymer adhesive includes: an aqueous solution of polyethylene oxide and an aqueous solution of an acrylic multi-polymer; A complex formed after complexation of shared electron pairs;

The polymer adhesive provided by the present invention, after the C-O-C bond in the polyethylene oxide is complexed with the main chain of the acrylate multi-polymer copolymer-C-C-, hydrogen is generated between the acrylate multi-polymer copolymer and the polyethylene oxide The complexation of the bond force makes the complex formed by the acrylate multi-polymer and polyethylene oxide not only have the cohesiveness of the acrylate multi-polymer, but also exhibit the flexibility of polyethylene oxide. The present invention The provided polymer binder, as a water-based binder, not only meets the requirements of green low-cost, but also can improve the low-temperature performance of the battery, and provides new raw materials, approaches and methods for the preparation of lithium-ion batteries.

Description of drawings

Fig. 1 is the comparison chart of the adhesion force of the pole piece prepared in Example 1-5 and the comparison pole piece using common oily binder in Comparative Example 1;

Fig. 2 is the comparison chart of the low-temperature performance of the electric core prepared by using the polymer binder in Examples 1-5 and the low-temperature performance of the comparative electric core using a conventional oily binder in Comparative Example 1;

FIG. 3 is a comparison chart of the cycle life of the battery cell prepared using the polymer binder in Examples 1-5 and the cycle life of the battery cell using a conventional oily binder in Comparative Example 1. FIG.

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Unless otherwise defined hereinafter, all technical and scientific terms used in the detailed description of the present invention have the same meanings as commonly understood by those skilled in the art. While the following terms are believed to be well understood by those skilled in the art, the following definitions are set forth to better explain the present invention.

As used herein, the terms "comprising", "comprising", "having", "containing" or "involving" are inclusive or open-ended and do not exclude other unrecited elements or method steps . The term "consisting of" is considered as a preferred embodiment of the term "comprising". If in the following a certain group is defined as comprising at least a certain number of embodiments, this is also to be understood as revealing a group which preferably consists only of these embodiments.

The use of an indefinite or definite article when referring to a noun in the singular eg "a" or "an", "the", includes a plural of that noun.

The term "approximately" in the present invention represents an accuracy range that can be understood by those skilled in the art and still guarantee the technical effect of the mentioned feature. The term generally means ±10%, preferably ±5%, of the indicated value.

In addition, the terms first, second, third, (a), (b), (c) and the like in the specification and claims are used to distinguish similar elements and are not necessary to describe the order or time order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments described herein are capable of operation in other sequences than described or illustrated herein.

Unless otherwise defined or clearly indicated by background, all technical and scientific terms in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

The technical solution of the present invention will be described in further detail below in conjunction with specific embodiments, but it does not constitute any limitation to the present invention. Anyone who makes a limited number of modifications within the scope of the claims of the present invention is still within the scope of the present invention. within the scope of the claims.

This embodiment provides a polymer adhesive, including: an aqueous solution of polyethylene oxide and an aqueous solution of an acrylate multi-polymer;

Wherein, the polymer adhesive is a complex formed by complexing the carboxyl group in the acrylate multi-polymer and the ether oxygen of polyethylene oxide to share electron pairs.

The above-mentioned multi-acrylic copolymer can be 306F. Its main chain is -C-C- main chain, which endows the binder with good chain rotation. The introduction of functional groups such as carboxyl groups and smaller particle size make the binder 306F exhibit excellent dispersion stability for lithium iron phosphate materials; the existence of polar functional side groups makes the binder exhibit excellent bonding performance.

In the existing adhesives, 306F glue is used alone or some additives are added, but the use of 306F glue has the problems of relatively brittle pole pieces, poor toughness, low compaction, and poor processability.

Polyethylene oxide (PEO) itself has C-O-C bonds, usually has flexibility, and can form associations with electron acceptors or certain inorganic electrolytes. In addition, due to the formation of hydrogen bonds, it becomes a neutral water-soluble The polymer, as well as its own viscosity, can be used as a binder to increase the flexibility of the pole piece and the electronic conductivity of the battery. Its aqueous solution is neutral and will not affect the acidity and alkalinity of the slurry. It is an excellent water-based bond. It can be used as a suspending agent to improve the stability of the slurry and prevent sedimentation; it can be used as a film-forming agent to promote film-forming during the coating process and enhance the flexibility of the coated pole piece.

PEO has ether oxygen non-shared electron pairs, and has a strong affinity for hydrogen bonds. Acrylic multipolymers contain a large number of carboxyl groups, which makes there be hydrogen bond forces between PEO and acrylate multipolymers. Complexation, after forming a complex between acrylate multi-polymer copolymer and PEO, it not only has the adhesiveness of acrylate multi-polymer copolymer, but also exhibits the flexibility of PEO. It is a good choice for water-based binder.

The polymer adhesive provided in this embodiment, after the C-O-C bond in the polyethylene oxide is complexed with the main chain of the acrylic multi-polymer copolymer-C-C-, creates a bond between the acrylic multi-polymer copolymer and the polyethylene oxide. The complexation of hydrogen bond forces makes the complex formed by acrylate multi-polymer and polyethylene oxide not only have the adhesiveness of acrylate multi-polymer, but also show the flexibility of polyethylene oxide. The polymer binder provided in the examples, as a water-based binder, not only meets the requirements of green and low cost, but also can improve the low-temperature performance of the battery, and provides new raw materials, approaches and methods for the preparation of lithium-ion batteries.

Further, in the polymer adhesive, the mass ratio of polyethylene oxide and acrylate multi-polymer is 1:(0.01-100).

Further, in the aqueous solution of polyethylene oxide, the molecular weight of polyethylene oxide is 1×10 ³ -1×10 ⁹ .

Further, in the aqueous solution of polyethylene oxide, the mass fraction of polyethylene oxide is 0.01%-15%.

In addition, this embodiment also provides a positive electrode slurry, including: positive electrode material, conductive agent, binder and solvent;

Wherein, the adhesive is a polymer adhesive as described above;

The ratio of the positive electrode material, the conductive agent and the binder is: (90-98):(0.01-10):(0.01-10).

In this example, the positive electrode slurry provided is prepared by mixing the above-mentioned basic solutions, and the operation is simple and the synthesis conditions are mild.

As mentioned above, the coating of the positive electrode slurry can not only improve the flexibility of the electrode sheet, but also have excellent low-temperature performance of the battery.

Further, the positive electrode material includes one or more of commonly used positive electrode materials such as lithium iron phosphate, lithium manganate, lithium cobaltate, sodium vanadium phosphate, sodium manganate, and sodium iron pyrophosphate.

Further, the conductive agent material includes: one of SP, acetylene black, 350G, carbon fiber, carbon nanotube, Ketjen black, KS-6, KS-15, SFG-6, SFG-15, graphene or Several kinds.

In addition, this embodiment also provides a method for preparing a polymer adhesive as described above, which is characterized in that it includes:

Step S10, adding polyethylene oxide particles into deionized water, and mixing to obtain an aqueous solution of polyethylene oxide;

Step S20, taking the acrylate multi-polymer, configuring it into an aqueous solution of the acrylate multi-polymer, and adding it to the polyethylene oxide aqueous solution;

Step S30, stirring and mixing under vacuum for 0.2-2 hours to obtain a polymer adhesive;

Further, the stirring and mixing time under vacuum is 0.5-1 hour.

Further, the mass fraction of the polyethylene oxide aqueous solution is 0.01% to 15%;

The mass fraction of the aqueous solution of the acrylate multi-polymer is 1% to 20%;

Further, the mass fraction of the polyethylene oxide aqueous solution is 2.0%-2.5%.

In addition, this embodiment also provides a method for preparing the positive electrode slurry as described above, including:

Step S100, adding a conductive agent into the aqueous binder solution, stirring and dispersing for 0.5 hours to 2 hours, to obtain a conductive solution;

Step S200, take the positive electrode material and add it to the conductive solution, first perform low-speed stirring at 5rpm-15rpm for 5 minutes-15 minutes, then perform high-speed stirring at 25rpm-35rpm for 0.5 hours-2 hours, after stirring and mixing, add deionized Stir and disperse with water to obtain positive electrode slurry;

Further, the high-speed stirring time is 0.8 hour-1 hour.

Further, when adding deionized water for stirring and dispersing, adjust the viscosity of the positive electrode slurry at 3000mPa·s-7000mPa·s, and the solid content is 35%-80%;

Further, the viscosity of the positive electrode slurry is 4500mPa·s-5500mPa·s, and the solid content is 55%-58%.

As mentioned above, the positive electrode slurry and its mixing method in the pulping process may include but not limited to one or more of dual planetary stirring, screw, ball milling, and ultrasonic.

As mentioned above, the coating of the positive electrode slurry involved in this embodiment can be extrusion coating, transfer coating, blade coating, ultrasonic spray coating;

As mentioned above, after the positive electrode slurry involved in this embodiment is coated, the cell preparation process may include winding and lamination, and the cell types may include square, cylindrical, soft pack, and buckle.

The present invention will be further described below through specific examples, but it should be understood that these examples are only used for more detailed description, and should not be construed as limiting the present invention in any form.

Embodiment 1 (bonding agent is PEO+306F)

(1) Dissolve 172g of PEO in 8153g of deionized water, stir at a revolution speed of 25RPM for 2h, and fully dissolve to obtain a PEO aqueous solution;

(2) Add 1441g 306F (13wt%) into the PEO aqueous solution prepared in step (1), and then stir at 25RPM for 0.5h to obtain a polymer binder solution;

(3) 156g of rigid nanoparticle-type Super P powder (conductive carbon black, conductive agent) and 1873g of aqueous CNTs solution (5wt%) (carbon nanotubes, conductive agent) were dissolved in (2) prepared polymer bond In the aqueous solution of the conductive agent, stir at a high speed of 25rpm and disperse at 2500rpm for 1h to obtain a conductive agent solution;

(4) Add 7500g SF13 iron lithium and 7500g K2 iron lithium (positive electrode material) to the conductive agent solution prepared in (3), stir and mix at a high speed of 25rpm for 1h, add 589gNMP, stir at a high speed of 25rpm under -80mPa vacuum, and disperse at 2500rpm for 1h Prepare a positive electrode slurry with a solid content of 56% and a viscosity of 4500-5500mPa·s;

(5) The positive electrode slurry prepared in (4) is made into a pole piece according to a mature preparation process to become a pole piece 1 , and then manufactured and assembled to obtain a finished battery cell 1 .

Embodiment 2 (bonding agent is PEO)

(1) Dissolve 359g of PEO in 9407g of deionized water, stir at a revolution speed of 25RPM for 2h, fully dissolve, and obtain an aqueous solution of PEO binder;

(2) 156g of rigid nanoparticle-type Super P powder and 1873g of aqueous CNTs solution (5wt%) were dissolved in the PEO binder aqueous solution prepared in (1), stirred at a high speed of 25rpm and dispersed at 2500rpm for 1h to obtain a conductive agent solution;

(3) Add 7500g SF13 iron lithium and 7500g K2 iron lithium to the conductive agent solution prepared in (2), stir and knead at 25rpm at high speed for 1h, add 589gNMP, stir at 25rpm at high speed under -80mPa vacuum, and disperse at 2500rpm for 1h to obtain a solid content About 56%, slurry with a viscosity of 4500-5500mPa·s;

(4) The slurry prepared in (3) is made into a pole piece according to a mature preparation process to become a pole piece 2 , and then manufactured and assembled to obtain a finished battery cell 2 .

Embodiment 3 (adhesive is 306F)

(1) 2762g 306F (13wt%) was added into 7004g water, stirred at 25RPM for 0.5h to obtain an aqueous binder solution;

(2) Dissolve 156g of rigid nanoparticle-type Super P powder and 1873g of aqueous CNTs solution (5wt%) in the aqueous binder solution prepared in (1), stir at a high speed of 25rpm, and disperse at 2500rpm for 1h to obtain a conductive agent solution;

(3) Add 7500g SF13 iron lithium and 7500g K2 iron lithium to the conductive agent solution prepared in (2), stir and knead at 25rpm at high speed for 1h, add 589gNMP, stir at 25rpm at high speed under -80mPa vacuum, and disperse at 2500rpm for 1h to obtain a solid content About 56%, slurry with a viscosity of 4500-5500mPa·s;

(4) The slurry prepared in (3) is made into a pole piece according to a mature preparation process to become a pole piece 3 , and then manufactured and assembled to obtain a finished battery cell 3 .

Embodiment 4 (bonding agent is PEO+306F)

(1) Dissolve 356g of PEO in 9386g of deionized water, stir at a revolution speed of 25RPM for 2h, fully dissolve, and obtain a PEO aqueous solution;

(2) Add 24g 306F (13wt%) into the PEO aqueous solution prepared in step (1), and then stir at 25RPM for 0.5h to obtain a polymer binder solution;

(3) 156g of rigid nanoparticle-type Super P powder (conductive carbon black, conductive agent) and 1873g of aqueous CNTs solution (5wt%) (carbon nanotubes, conductive agent) were dissolved in (2) prepared polymer bond In the aqueous solution of the conductive agent, stir at a high speed of 25rpm and disperse at 2500rpm for 1h to obtain a conductive agent solution;

(4) Add 7500g SF13 iron lithium and 7500g K2 iron lithium (positive electrode material) to the conductive agent solution prepared in (3), stir and mix at a high speed of 25rpm for 1h, add 589gNMP, stir at a high speed of 25rpm under -80mPa vacuum, and disperse at 2500rpm for 1h Prepare a positive electrode slurry with a solid content of 56% and a viscosity of 4500-5500mPa·s;

(5) The positive electrode slurry prepared in (4) is made into a pole piece according to a mature preparation process to become a pole piece 4 , and then manufactured and assembled to obtain a finished battery cell 4 .

Embodiment 5 (bonding agent is PEO+306F)

(1) Dissolve 125g of PEO in 6455g of deionized water, stir at a revolution speed of 25RPM for 2h, fully dissolve, and obtain a PEO aqueous solution;

(2) Add 2738g 306F (13wt%) into the PEO aqueous solution prepared in step (1), and then stir at 25RPM for 0.5h to obtain a polymer binder solution;

(3) 156g of rigid nanoparticle-type Super P powder (conductive carbon black, conductive agent) and 1873g of aqueous CNTs solution (5wt%) (carbon nanotubes, conductive agent) were dissolved in (2) prepared polymer bond In the aqueous solution of the conductive agent, stir at a high speed of 25rpm and disperse at 2500rpm for 1h to obtain a conductive agent solution;

(4) Add 7500g SF13 iron lithium and 7500g K2 iron lithium (positive electrode material) to the conductive agent solution prepared in (3), stir and mix at a high speed of 25rpm for 1h, add 589gNMP, stir at a high speed of 25rpm under -80mPa vacuum, and disperse at 2500rpm for 1h Prepare a positive electrode slurry with a solid content of 56% and a viscosity of 4500-5500mPa·s;

(5) The positive electrode slurry prepared in (4) is made into a pole piece according to a mature preparation process to become a pole piece 5 , and then manufactured and assembled to obtain a finished battery cell 5 .

Comparative example 1

(1) Dissolve 155.4g of PVDF915 in 2919g of NMP. After the feeding is completed, the speed is gradually increased to the set value. After stirring for 10 minutes, scrape the wall and shovel the bottom and then continue. Stir for 2 hours at a revolution speed of 25RPM, fully dissolve, and obtain PVDF glue;

(2) 77.8g of rigid nanoparticle type Super P powder and 777g of oily CNTs solution (5wt%) were dissolved in the PVDF glue obtained in (1), stirred at a high speed of 25rpm, and dispersed for 1h at 2500rpm to obtain a conductive agent solution;

(3) Add 7500g SF13 iron lithium and 7500g K2 iron lithium to the conductive agent solution prepared in (2), stir and knead at 25rpm at high speed for 1h, 1971gNMP, stir at 25rpm at high speed under -80mPa vacuum, and disperse at 2500rpm for 1h to obtain a solid content of 58 % or so, viscosity 4500-5500mPa·s slurry.

(4) The slurry prepared in (3) is made into a pole piece according to a mature preparation process to become a comparison pole piece, and then manufactured and assembled to obtain a finished comparison battery cell.

Experimental results:

Table 1, embodiment 1-5 and comparative example 1 pole piece adhesion and flexibility test result

1. First, in this experiment, for the pole pieces prepared in Examples 1-5 and Comparative Example 1, tests of adhesion and flexibility were carried out respectively.

It can be seen from Table 1 that the pole piece 2 in Example 2 simply uses PEO as a binder, although the pole piece does not break when folded in half and has a certain degree of flexibility, but has cross adhesion. Since the pole piece 3 simply uses 306F as a binder, the pole piece also has a certain degree of adhesion, but the pole piece breaks in the flexibility test of folding in half, indicating that its flexibility is crossed, and the winding operation cannot be realized, and the process performance is poor. ; and pole piece 1 in embodiment 1, owing to use the polymer binding agent that PEO and 306F are prepared jointly, wherein PEO has ether oxygen non-shared electron pair, has very strong affinity to hydrogen bond, contains a large amount of in 306F The carboxyl group, which makes the complexation of hydrogen bond force between PEO and 306F, 306F and PEO form a complex not only has the adhesiveness of 306F, but also shows the flexibility of PEO, so the pole piece 1 It not only has good cohesiveness, but also shows outstanding flexibility when folded in half and not easy to break. In Example 3, 306F is used alone as the adhesive, which is prone to fracture due to the poor toughness due to the physical and chemical properties of the acrylate multi-polymer copolymer.

2. For the pole pieces 1-5 in Examples 1-5, and the comparison pole piece in the ordinary oily binder (comparative example 1), the adhesion test was carried out respectively. As can be seen from Figure 1, using this The adhesion force of the pole piece with water-based binder after rolling is 382.93N/m, which is significantly higher than that of the comparison pole piece with conventional oily binder, which is 246.72N/m.

Table 2, Examples 1-5 and Comparative Example 1 battery cell low-temperature discharge test results

3. For the battery cell 1 in Example 1, compare its low-temperature performance with the low-temperature performance of the battery cell using a conventional oily binder. It can be seen from Table 2 and Figure 2 that the battery cell using this water-based binder is The 1C discharge capacity retention rate at -20°C is 89.20%. The 1C discharge capacity retention rate of the conventional oily binder is only 76.89% at -20°C. The low temperature performance of the water-based binder is significantly higher than that of the conventional cell. Comparison cell with oily binder.

4. For the battery cell 1 in Example 1, compare its cycle life with the cycle life of the battery cell using a conventional oily binder. It can be seen from Figure 3 that the battery cell 1.2C charge and discharge using this water-based binder , 3140 cycles, the capacity is 44.27Ah, the capacity retention rate is still 84.18%, the conventional oil system is charged and discharged at 1C, the cycle is 2222 cycles, the capacity is 41.56Ah, the capacity retention rate is 79.99% (it has fallen below 80%). The cell cycle life of water-based binder is significantly higher than that of conventional oil-based binder.

What have been described above are the preferred implementation modes and corresponding examples of the present invention. It should be pointed out that for those skilled in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, including but It is not limited to the adjustment of ratio, flow process, and dosage, and these all belong to the scope of protection of the present invention. What have been described above are the preferred implementation modes and corresponding examples of the present invention. It should be pointed out that for those skilled in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, including but It is not limited to the adjustment of ratio, flow process, and dosage, and these all belong to the scope of protection of the present invention.

Claims (10)

1. A polymer adhesive, characterized in that, comprising: an aqueous solution of polyoxyethylene and an aqueous solution of acrylic acid ester multi-polymer; Wherein, the polymer adhesive is a complex formed by complexing the carboxyl group in the acrylate multi-polymer and the ether oxygen of polyethylene oxide to share electron pairs; Preferably, in the polymer adhesive, the mass ratio of polyethylene oxide and acrylate multi-polymer is 1:(0.01-100). 2. The polymer adhesive according to claim 1, wherein in the aqueous solution of polyethylene oxide, the molecular weight of polyethylene oxide is 1×10 ³ -1×10 ⁹ . 3. The polymer adhesive according to claim 1, characterized in that, in the aqueous solution of polyethylene oxide, the mass fraction of polyethylene oxide is 0.01%-15%. 4. A positive electrode slurry, characterized in that, comprising: positive electrode material, conductive agent, binder and solvent; Wherein, the adhesive is the polymer adhesive according to any one of claims 1-3; The ratio of the positive electrode material, the conductive agent and the binder is: (90-98):(0.01-10):(0.01-10). 5. positive electrode slurry as claimed in claim 4, is characterized in that, described positive electrode material comprises lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, sodium vanadium phosphate, sodium manganate, sodium iron pyrophosphate etc. commonly used positive electrode materials one or more species. 6. The positive electrode slurry according to claim 4, wherein the conductive agent material comprises: SP, acetylene black, 350G, carbon fiber, carbon nanotube, Ketjen black, KS-6, KS-15, SFG- 6. One or more of SFG-15 and graphene. 7. A preparation method of polymer adhesive according to any one of claims 1-3, characterized in that, comprising: Add polyethylene oxide particles into deionized water, and mix to obtain polyethylene oxide aqueous solution; Take the acrylate multi-polymer, configure it into an aqueous solution of the acrylate multi-polymer, and add it to the polyethylene oxide aqueous solution; Stirring and mixing under vacuum for 0.2-2 hours to obtain a polymer adhesive; Preferably, the stirring and mixing time under vacuum is 0.5-1 hour. 8. The preparation method of the polymer adhesive according to claim 7, wherein the mass fraction of the polyoxyethylene aqueous solution is 0.01% to 15%; The mass fraction of the aqueous solution of the acrylate multi-polymer is 1% to 20%; Preferably, the mass fraction of the polyethylene oxide aqueous solution is 2.0%-2.5%. 9. A method for preparing positive electrode slurry as claimed in claim 4, characterized in that, comprising: Add the conductive agent to the aqueous binder solution, stir and disperse for 0.5 hours to 2 hours to obtain a conductive solution; Take the positive electrode material and add it to the conductive solution, first perform low-speed stirring at 5rpm-15rpm for 5 minutes-15 minutes, then perform high-speed stirring at 25rpm-35rpm for 0.5 hours-2 hours, after stirring and mixing, add deionized water for stirring and dispersed to obtain the positive electrode slurry; Preferably, the time for high-speed stirring is 0.8 hour-1 hour. 10. The preparation method of positive electrode slurry as claimed in claim 9, is characterized in that, when adding deionized water to stir and disperse, adjust the viscosity of the positive electrode slurry at 3000mPa·s-7000mPa·s, solid content 35%-80%; Preferably, the positive electrode slurry has a viscosity of 4500mPa·s-5500mPa·s, and a solid content of 55%-58%.

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