Coating composition for improving liquid leakage resistance, liquid absorption and discharge performance of battery and application of coating composition

Abstract

The invention relates to the technical field of batteries, in particular to a coating composition for improving leakage resistance, liquid absorption and discharge performance of a battery and application of the coating composition. The prepared coating composition comprises the following raw materials in percentage by mass: 10%-25% of a methacrylate-acrylamide block copolymer, 10%-15% of polyvinyl alcohol, 40%-53% of starch, 1%-5% of an inorganic-organic composite corrosion inhibitor, 0.5%-2% of a compound surfactant and the balance of water. The invention also provides a preparation method of the coating composition and an application of the coating composition in a zinc-manganese dry battery, and the coating composition is used for preparing coated paper so as to improve the leakage resistance, liquid absorption and discharge performance of the battery. According to the invention, the methacrylate monomer is introduced into the traditional polyacrylamide hydrogel polymerization process, so that the liquid absorption amount and the liquid absorption rate are remarkably improved, the leakage resistance of the battery is improved, the liquid absorption amount is doubled, the discharge time is prolonged by 10%, and the retention rate reaches 95% or more after the battery is naturally stored for half a year.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a coating composition and its application for improving the leakage resistance, liquid absorption and discharge performance of batteries. Background Technology

[0002] Zinc-manganese dry cell batteries, as one of the most widely used disposable batteries globally, occupy an important position in consumer electronic devices, small appliances, and emergency power supply fields due to their low cost and ease of use. The slurry paper, as the core separator component between the positive and negative electrodes of the zinc-manganese dry cell battery, directly determines the battery's discharge and storage performance. The slurry paper must possess both good isolation and good ion permeability. This requires the slurry paper coating to have good liquid absorption and retention properties, absorbing a large amount of electrolyte to reduce leakage and corrosion caused by sealing problems, while also possessing good adhesion and swelling properties to extend battery life. However, the liquid absorption, retention, and leakage resistance properties of existing slurry paper coatings are still not ideal.

[0003] Traditional coating materials often use single polymers such as polyacrylamide, starch, or polyvinyl alcohol, which have limited swelling and hydrophilicity, resulting in low liquid absorption, slow absorption rate, and poor liquid retention stability of the pulp paper. This not only leads to insufficient electrolyte supply during battery discharge, causing discharge voltage fluctuations and capacity decay, but also easily causes battery leakage due to electrolyte seepage, corroding electrical equipment and affecting safety. Existing coating materials lack sufficient mechanical strength and film density, making them prone to swelling, deformation, and structural loosening during electrolyte immersion or long-term battery storage, leading to electrolyte leakage from coating pores. Simultaneously, poor adhesion between the coating and the base paper and electrode surfaces makes peeling more likely, further exacerbating the risk of leakage and severely limiting battery shelf life and reliability.

[0004] Hydrogen evolution corrosion of the zinc electrode is a core factor leading to self-discharge, capacity loss, and shortened lifespan in zinc-manganese dry batteries. Currently, the industry commonly uses inorganic corrosion inhibitors such as bismuth oxide (Bi₂O₃) to replace toxic mercury-based corrosion inhibitors. These inhibitors suppress corrosion by forming a passivation film on the zinc electrode surface. However, the corrosion inhibition mechanism of a single inhibitor is limited, making it difficult to comprehensively suppress the corrosion process of the zinc electrode, resulting in limited corrosion inhibition efficiency. While some corrosion inhibitors can inhibit corrosion to a certain extent, they affect the polarization characteristics and ion conduction efficiency of the zinc electrode, leading to a decline in battery discharge performance, failing to balance corrosion inhibition and discharge stability. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a pulp-paper coating composition and its preparation method for improving the leakage resistance, liquid absorption, and discharge performance of batteries. The coating composition uses a block polymer with excellent liquid absorption, mechanical properties, and film-forming properties, which effectively improves the leakage resistance of the battery during discharge. An inorganic-organic composite corrosion inhibitor is used to form a tetrahedral complex with Zn, which inhibits hydrogen evolution and corrosion of the Zn electrode and maintains good discharge performance.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A coating composition for improving the resistance to leakage, liquid absorption and discharge of batteries, the coating composition comprising: methacrylate-acrylamide block copolymer, polyvinyl alcohol, starch, inorganic-organic composite corrosion inhibitor, compound surfactant and water.

[0008] Furthermore, the mass percentage of each component in the coating composition is as follows: 10%-25% methacrylate-acrylamide block copolymer, 10%-15% polyvinyl alcohol, 40%-53% starch, 1%-5% inorganic-organic composite corrosion inhibitor, 0.5%-2% compound surfactant, and the remainder is water.

[0009] Furthermore, the methacrylate-acrylamide block copolymer has a number-average molecular weight of 10,000 g / mol to 5,000,000 g / mol and a polymer dispersion index (PDI) of 1 to 3.

[0010] The methacrylate is selected from one or more of methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isooctyl methacrylate, and lauryl methacrylate; in the methacrylate-acrylamide block copolymer, the mass ratio of methacrylate to acrylamide is (0.01:0.99)-(0.25:0.75).

[0011] Furthermore, the inorganic-organic composite corrosion inhibitor is bismuth oxide and triethanolamine; the mass ratio of bismuth oxide to triethanolamine is (1:99)-(5:95).

[0012] Furthermore, the compound surfactant is composed of a basic nonionic surfactant and a modified nonionic surfactant, wherein the basic nonionic surfactant is OP 10 or Span 80, and the modified nonionic surfactant is Tween 80, Tween 60, or Tween 40; the mass ratio of the basic nonionic surfactant to the modified nonionic surfactant is 1:1.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned coating composition for improving the battery's resistance to leakage, liquid absorption, and discharge performance, comprising the following steps:

[0014] First, weigh each raw material according to the mass percentage of each component in the coating composition, then dissolve polyvinyl alcohol in hot water to obtain a 30% polyvinyl alcohol solution; divide the starch by mass, half of which is gelatinized and the other half is not gelatinized; add the gelatinized and ungelatinized starch and the inorganic corrosion inhibitor from the inorganic-organic composite corrosion inhibitor to the polyvinyl alcohol solution to obtain a mixed solution; after preparing the methacrylate-acrylamide block copolymer, mix the mixed solution with the methacrylate-acrylamide block copolymer evenly to obtain the aqueous slurry composition, i.e., the coating composition.

[0015] Further, the steps for preparing the methacrylate-acrylamide block copolymer are as follows: methacrylate is first mixed evenly with a basic nonionic surfactant, and then a modified nonionic surfactant is added and mixed evenly. The resulting mixture is added together with the organic corrosion inhibitor in the inorganic-organic composite corrosion inhibitor to a 60% acrylamide aqueous solution for polymerization reaction. After mixing evenly, an initiator is selectively added, and the mixture is heated to carry out polymerization reaction to obtain a colorless, transparent, and viscous methacrylate-acrylamide block copolymer.

[0016] Further, the polymerization reaction is as follows: an initiator is added to initiate the formation of a colorless, transparent, viscous block copolymer from methyl methacrylate and acrylamide. The initiator is azobisisobutyronitrile (AIBN), and the concentration of AIBN initiating the polymerization is 0-0.025% of the total mass of the coating composition.

[0017] Furthermore, the polymerization reaction is as follows: heating is carried out thermally to initiate the formation of a colorless, transparent, viscous block copolymer from methyl methacrylate and acrylamide, with the heating temperature being 50℃-100℃ and the time being 3min-60min.

[0018] Thirdly, the present invention provides the application of the above-mentioned coating composition for improving the battery's resistance to leakage, absorption and discharge performance in zinc-manganese dry batteries, for the preparation of pulp paper to improve the battery's resistance to leakage, absorption and discharge performance.

[0019] Furthermore, the preparation of pulp paper involves coating the base paper with a coating composition and then drying it to obtain pulp paper with the coating composition.

[0020] Advantages and effects of the present invention:

[0021] This invention introduces methacrylate monomers into the traditional polyacrylamide hydrogel polymerization process. This not only increases the viscosity of the polymerization reaction, thereby improving the adhesion of the methacrylate-acrylamide block copolymer hydrogel, which is beneficial for its tight bonding with the Zn electrode surface, but also, under the thermal polymerization action of an initiator or without an initiator, acrylamide and methacrylate copolymerize to obtain the methacrylate-acrylamide block copolymer. Compared with polyacrylamide, the methacrylate-acrylamide block copolymer hydrogel exhibits improved swelling properties, significantly increasing the liquid absorption capacity and absorption rate, thus improving the battery's leakage resistance. The liquid absorption capacity is doubled, and the absorption rate is increased by 20%, which is more conducive to the absorption and retention of electrolyte, further improving the battery's leakage resistance.

[0022] This invention utilizes the synergistic effect between molecules, employing an inorganic-organic composite corrosion inhibitor. By leveraging different corrosion inhibition mechanisms, it achieves complementary advantages between the inhibitor molecules. The inorganic-organic composite corrosion inhibitor can form a tetrahedral complex with Zn, which can better inhibit Zn corrosion, significantly improving corrosion inhibition efficiency. It can minimize the amount of hydrogen produced by the zinc electrode in zinc-manganese dry batteries, improve the conductivity of the zinc electrode and the utilization rate of active materials, and extend battery life. Compared with using inorganic corrosion inhibitors alone, the discharge time is increased by 10%, and the retention rate reaches over 95% after six months of natural storage. Attached Figure Description

[0023] Figure 1 The IR spectrum of the methacrylate-acrylamide block copolymer prepared in Example 1 of this invention;

[0024] Figure 2 This is a comparison diagram of the swelling properties of the methacrylate-acrylamide block copolymer prepared in Example 1 of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0026] A pulp-paper coating composition for improving battery resistance to leakage, liquid absorption, and discharge, comprising, by mass percentage: 10%-25% methacrylate-acrylamide block copolymer, 10%-15% polyvinyl alcohol, 40%-53% starch, 1%-5% inorganic-organic composite corrosion inhibitor, 0.5%-2% compound surfactant, and the remainder being water. The methacrylate-acrylamide block copolymer has a number-average molecular weight of 10,000 g / mol-5,000,000 g / mol and a polymer dispersion index (PDI) of 1-3. The methacrylate is selected from one or more of methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isooctyl methacrylate, and lauryl methacrylate. The inorganic-organic composite corrosion inhibitor is bismuth oxide and triethanolamine in a mass ratio of (1:99)-(5:95). The compound surfactant consists of an equal mass ratio of a basic nonionic surfactant and a modified nonionic surfactant, wherein the basic nonionic surfactant is OP. 10 or Span80, and modified nonionic surfactants are Tween 80, Tween 60 or Tween 40.

[0027] A method for preparing a coating composition to improve the resistance to leakage, liquid absorption, and discharge of a battery includes the following steps:

[0028] First, weigh each raw material according to the mass percentage of each component in the coating composition, then dissolve polyvinyl alcohol in hot water to obtain a 30% polyvinyl alcohol solution; divide the starch by mass, half of which is gelatinized and the other half is not gelatinized; add the gelatinized and ungelatinized starch and the inorganic corrosion inhibitor from the inorganic-organic composite corrosion inhibitor to the polyvinyl alcohol solution to obtain a mixed solution; after preparing the methacrylate-acrylamide block copolymer, mix the mixed solution with the methacrylate-acrylamide block copolymer evenly to obtain the aqueous slurry composition, i.e., the coating composition.

[0029] Preparation of methacrylate-acrylamide block copolymer: Methacrylate is first mixed evenly with a basic nonionic surfactant, then a modified nonionic surfactant is added and mixed evenly. The resulting mixture, along with the organic corrosion inhibitor from the inorganic-organic composite corrosion inhibitor, is added to a 60% acrylamide aqueous solution. The mass ratio of methacrylate to acrylamide is (0.01:0.99)-(0.25:0.75). After mixing evenly, the initiator azobisisobutyronitrile is selectively added to initiate the formation of a colorless, transparent, viscous block copolymer between methyl methacrylate and acrylamide. Alternatively, polymerization can be initiated at 50℃-100℃ for 3-60 minutes to form a colorless, transparent, viscous block copolymer. The polymerization reaction formula is as follows. Figure 1The IR spectrum of the methacrylate-acrylamide block copolymer is shown. Figure 2 This is a comparison diagram of the swelling properties of the methacrylate-acrylamide block copolymer prepared in Example 1 of the present invention.

[0030]

[0031] Preparation of coating composition: The pre-mixed mixture solution is mixed evenly with methacrylate-acrylamide block copolymer to obtain an aqueous slurry composition, i.e., coating composition.

[0032] The application of a coating composition for improving the leakage resistance, liquid absorption and discharge performance of a battery in a zinc-manganese dry cell involves coating the coating composition onto the surface of a base paper and then drying it to obtain a pulp paper with the coating composition, thereby improving the battery's leakage resistance, liquid absorption and discharge performance.

[0033] This invention selects polymethyl methacrylate (PMMA) based on its excellent optical and electrical properties, good chemical stability, and good adhesion and compatibility with fibers. PMMA is resistant to acids, alkalis, and salts, and does not exhibit side reactions such as hydrolysis, segregation, or degradation in electrolytes; it is also well-miscible with starch and polyvinyl alcohol slurries. PMMA monomers have a certain solubility in water, and acrylamide is also soluble in PMMA monomers; the introduction of PMMA causes some unique changes during the polymerization of block copolymers, which is beneficial for improving the performance of traditional polyacrylamide.

[0034] This invention selects a composite corrosion inhibitor of bismuth oxide and triethanolamine. Triethanolamine is readily available, highly soluble, and has good stability. The N and O in triethanolamine can form complex bonds with zinc, generating one or more zinc complexes on the surface of the Zn electrode in the corrosive medium. This isolates the Zn electrode surface from the corrosive medium, inhibiting the cathode and anodic reaction processes and the corrosion of the zinc electrode. When the battery is working, the passivation film or complex bonds decompose due to the potential change, without affecting the polarization of the anodic zinc, allowing the current to pass through normally and conduct electricity.

[0035] Example 1

[0036] A method for preparing a pulp-paper coating composition to improve the battery's resistance to leakage, liquid absorption, and discharge performance includes the following steps:

[0037] Weigh the following components:

[0038] 25 g of methyl methacrylate

[0039] Acrylamide 225g

[0040] 150g of polyvinyl alcohol

[0041] 500g of starch

[0042] Bi2O3 0.5g

[0043] 50g of triethanolamine

[0044] OP10 10g

[0045] Tween60 10g

[0046] Azobisisobutyronitrile 0.25g

[0047] 29g of water

[0048] First, weigh each raw material according to the mass percentage of each component in the coating composition, then dissolve polyvinyl alcohol in hot water to obtain a 30% polyvinyl alcohol solution; gelatinize 250g of starch and leave 250g of starch ungelatinized, and mix all starch and Bi2O3 into the polyvinyl alcohol solution to obtain a mixed solution; mix methyl methacrylate with OP10 first, then add Tween60 and mix again; add the mixture of methyl methacrylate and surfactant and triethanolamine to a 60% acrylamide aqueous solution, mix evenly, and then add azobisisobutyronitrile to initiate the formation of a colorless, transparent, viscous methyl methacrylate-acrylamide block copolymer; finally, mix the block copolymer with the mixed solution evenly to form an aqueous slurry of the composition, in which the composition accounts for approximately 40%, i.e., the coating composition.

[0049] The application of a coating composition for improving the leakage resistance, liquid absorption and discharge performance of a battery in a zinc-manganese dry cell involves coating the coating composition onto the surface of a base paper and then drying it to obtain a pulp paper with the coating composition, thereby improving the battery's leakage resistance, liquid absorption and discharge performance.

[0050] Example 2

[0051] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is changed from methyl methacrylate to n-butyl methacrylate, while other components and contents remain unchanged.

[0052] Example 3

[0053] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is changed from methyl methacrylate to isobutyl methacrylate, while other components and contents remain unchanged.

[0054] Example 4

[0055] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper is changed from methyl methacrylate to isooctyl methacrylate, while other components and contents remain unchanged.

[0056] Example 5

[0057] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper is changed from methyl methacrylate to lauryl methacrylate, while other components and contents remain unchanged.

[0058] Example 6

[0059] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of methyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0060] Example 7

[0061] The difference from Example 2 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of n-butyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0062] Example 8

[0063] The difference from Example 3 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of isobutyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0064] Example 9

[0065] The difference from Example 4 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of isooctyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0066] Example 10

[0067] The difference from Example 5 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of lauryl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0068] Example 11

[0069] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is modified so that the amount of triethanol in the composition is reduced from 5g to 3g, and the remainder is made up with water.

[0070] Example 12

[0071] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is changed from OP10 to Span 80.

[0072] Example 13

[0073] The difference from Example 1 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is modified by changing the amount of azobisisobutyronitrile in the composition from 0.25g to 0.1g.

[0074] Example 14

[0075] An aqueous slurry for coating composition is prepared from a composition that improves the leakage resistance, liquid absorption, and discharge performance of battery-grade paper. After the aqueous slurry is coated onto the surface of the base paper and dried, the composition that improves the leakage resistance, liquid absorption, and discharge performance of battery-grade paper remains. Its specific components are:

[0076] 25 g of methyl methacrylate

[0077] Acrylamide 225g

[0078] 150g of polyvinyl alcohol

[0079] 500g of starch

[0080] Bi2O3 0.5g

[0081] 50g of triethanolamine

[0082] OP10 10g

[0083] Tween60 10g

[0084] 29.5g of water

[0085] The process for preparing the aqueous slurry of the composition is as follows:

[0086] Polyvinyl alcohol is dissolved in hot water. 250g of starch is gelatinized, and 250g of starch is not gelatinized. All starch and Bi2O3 are mixed into the polyvinyl alcohol solution. Methyl methacrylate is first mixed evenly with OP10, and then Tween60 is added and mixed evenly. The mixture of methyl methacrylate and surfactant and triethanolamine are added to the acrylamide aqueous solution and mixed evenly. After mixing evenly, the mixture is heated at 50°C for 1 hour to thermally initiate the formation of a colorless, transparent, viscous block copolymer between methyl methacrylate and acrylamide. Finally, the block copolymer is mixed evenly with the mixture solution to form an aqueous slurry of the composition, in which the composition accounts for approximately 40%.

[0087] Example 15

[0088] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper is changed from methyl methacrylate to n-butyl methacrylate, while other components and contents remain unchanged.

[0089] Example 16

[0090] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is changed from methyl methacrylate to isobutyl methacrylate, while other components and contents remain unchanged.

[0091] Example 17

[0092] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery slurry paper is changed from methyl methacrylate to isooctyl methacrylate, while other components and contents remain unchanged.

[0093] Example 18

[0094] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper is changed from methyl methacrylate to lauryl methacrylate, while other components and contents remain unchanged.

[0095] Example 19

[0096] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of methyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0097] Example 20

[0098] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of n-butyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0099] Example 21

[0100] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of isobutyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0101] Example 22

[0102] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of isooctyl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0103] Example 23

[0104] The difference from Example 14 is that the composition for improving the leakage resistance, liquid absorption and discharge performance of battery pulp paper has the following changes: the amount of lauryl methacrylate in the composition is changed from 25g to 12.5g, and the amount of acrylamide is changed from 225g to 237.5g.

[0105] Table 1 shows the test performance of batteries using the pulp-paper coated compositions prepared according to the embodiments of the present invention.

[0106]

[0107] Note: *Discharge time after 6 months of storage at room temperature / discharge time of new battery

[0108] The pulp-paper coating composition prepared in the embodiments of this invention, when applied to zinc-manganese dry batteries, exhibits significantly superior performance compared to the control group. Regarding liquid absorption, the highest liquid absorption rate in the embodiments reached 300.1%, an improvement of approximately 48% compared to the control group; the fastest liquid absorption rate was only 2.7 seconds, a reduction of approximately 54% compared to the control group. In most embodiments, the liquid absorption volume doubled, and the liquid absorption rate increased by more than 20%, significantly enhancing the electrolyte's liquid absorption and retention capabilities. In terms of hydrogen evolution suppression, the lowest hydrogen evolution rate in the embodiments was only 0.8 mL / h, a reduction of up to 83.7% compared to the control group, effectively inhibiting zinc electrode corrosion and reducing hydrogen production. Regarding discharge performance, the highest discharge time retention rate in the embodiments reached 99.8%, an improvement of approximately 12.3% compared to the control group, significantly improving the conductivity of the zinc electrode and the utilization rate of active materials. All embodiments demonstrated excellent leakage resistance with no leakage, resulting in a significant extension of battery life.

Claims

1. A coating composition for improving the resistance to leakage, liquid absorption, and discharge of batteries, characterized in that, The coating composition comprises: methacrylate-acrylamide block copolymer, polyvinyl alcohol, starch, inorganic-organic composite corrosion inhibitor, compound surfactant and water.

2. The coating composition for improving battery resistance to leakage, liquid absorption, and discharge as described in claim 1, characterized in that, The coating composition comprises the following components by mass percentage: 10%-25% methacrylate-acrylamide block copolymer, 10%-15% polyvinyl alcohol, 40%-53% starch, 1%-5% inorganic-organic composite corrosion inhibitor, 0.5%-2% compounded surfactant, and the remainder is water.

3. The coating composition for improving battery resistance to leakage, liquid absorption, and discharge as described in claim 1, characterized in that, The methacrylate-acrylamide block copolymer has a number-average molecular weight of 10,000 g / mol to 5,000,000 g / mol and a polymer dispersion index (PDI) of 1 to 3. The methacrylate is selected from one or more of methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isooctyl methacrylate, and lauryl methacrylate; in the methacrylate-acrylamide block copolymer, the mass ratio of methacrylate to acrylamide is (0.01:0.99)-(0.25:0.75).

4. The coating composition for improving battery resistance to leakage, liquid absorption, and discharge as described in claim 1, characterized in that, The inorganic-organic composite corrosion inhibitor is bismuth oxide and triethanolamine; the mass ratio of bismuth oxide to triethanolamine is (1:99)-(5:95).

5. The coating composition for improving battery resistance to leakage, liquid absorption, and discharge as described in claim 1, characterized in that, The compound surfactant is composed of a basic nonionic surfactant and a modified nonionic surfactant, wherein the basic nonionic surfactant is OP 10 or Span 80, and the modified nonionic surfactant is Tween 80, Tween 60 or Tween 40; the mass ratio of the basic nonionic surfactant to the modified nonionic surfactant is 1:

1.

6. A method for preparing a coating composition according to any one of claims 1-5 for improving the leakage resistance, liquid absorption, and discharge performance of a battery, characterized in that, Includes the following steps: First, weigh each raw material according to the mass percentage of each component in the coating composition, then dissolve the polyvinyl alcohol in hot water to obtain a 30% polyvinyl alcohol solution. The starch is divided into equal parts by weight, half of which is gelatinized and the other half is not gelatinized. The gelatinized and ungelatinized starches, along with the inorganic corrosion inhibitor from the inorganic-organic composite corrosion inhibitor, are added to a polyvinyl alcohol solution to obtain a mixed solution. After preparing a methacrylate-acrylamide block copolymer, the mixed solution is mixed evenly with the methacrylate-acrylamide block copolymer to obtain an aqueous slurry composition, i.e., a coating composition.

7. The method for preparing the coating composition for improving the battery's resistance to leakage, liquid absorption, and discharge as described in claim 6, characterized in that, The steps for preparing methacrylate-acrylamide block copolymer are as follows: methacrylate is first mixed evenly with a basic nonionic surfactant, and then a modified nonionic surfactant is added and mixed evenly. The resulting mixture is added together with the organic corrosion inhibitor in the inorganic-organic composite corrosion inhibitor to a 60% acrylamide aqueous solution for polymerization reaction. After mixing evenly, an initiator is selectively added and heated to carry out polymerization reaction to obtain a colorless, transparent, viscous methacrylate-acrylamide block copolymer.

8. The method for preparing the coating composition for improving the battery's resistance to leakage, liquid absorption, and discharge according to claim 7, characterized in that, The polymerization reaction is as follows: an initiator is added to initiate the formation of a colorless, transparent, viscous block copolymer from methyl methacrylate and acrylamide. The initiator is azobisisobutyronitrile (AIBN), and the concentration of AIBN for initiating polymerization is 0-0.025% of the total mass of the coating composition.

9. The method for preparing the coating composition for improving the battery's resistance to leakage, liquid absorption, and discharge according to claim 7, characterized in that, The polymerization reaction is as follows: heating is carried out thermally to initiate the formation of a colorless, transparent, viscous block copolymer from methyl methacrylate and acrylamide. The heating temperature is 50℃-100℃ and the time is 3min-60min.

10. The application of the coating composition according to any one of claims 1-5, which improves the resistance to leakage, liquid absorption, and discharge of batteries, in a zinc-manganese dry cell battery, characterized in that, This material is used to prepare pulp paper to improve the battery's resistance to leakage, liquid absorption, and discharge. The preparation of pulp paper involves coating a coating composition onto the surface of a base paper and drying it to obtain pulp paper with the coating composition.

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