High-rate lead-acid storage battery negative plate and preparation method thereof

Abstract

The invention discloses a high-rate lead-acid storage battery negative plate and a preparation method, and relates to the technical field of batteries, and negative electrode lead paste comprises lead powder, barium sulfate, sodium lignosulfonate, a polycarboxylate pyrrole coated carbon nanotube-PbO-PbS composite material and hydrophilic modified polyester high-strength fibers. The composite material takes a multi-walled carbon nanotube as a substrate, a lead-based MOF precursor is constructed through reaction, a nitrogen-sulfur co-doped carbon nanotube loaded porous PbO-PbS heterojunction is obtained through high-temperature pyrolysis, and a polycarboxylate pyrrole layer is coated through in-situ chemical oxidation polymerization. The hydrophilic modified polyester fiber is obtained through graft modification of polyethylene glycol diglycidyl ether. The lead sulfate is induced to be uniformly deposited through the lattice matching effect of PbS, the carbon nanotubes construct a three-dimensional conductive network, the polycarboxylate pyrrole layer enhances the interface affinity, and the modified fibers guarantee the structural integrity of the electrode plate, so that the cycle life and the stability of the negative electrode plate in a high-rate partial charge state are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a high-rate lead-acid battery negative electrode plate and its preparation method. Background Technology

[0002] Lead-acid batteries hold a significant market position in automotive starting, electric bicycles, energy storage, and industrial backup power due to their advantages such as high safety, low cost, and well-established recycling systems. In recent years, however, the increasing demands on battery power characteristics from start-stop systems, hybrid vehicles, and renewable energy storage have required lead-acid batteries to withstand frequent high-rate charge-discharge shocks under partial charge conditions, posing a severe challenge to the cycle stability of the negative plates.

[0003] Under high-rate partial-charge conditions, the negative electrode plate faces two major failure mechanisms. First, the lead sulfate generated during discharge fails to be converted into spongy lead in time, gradually accumulating and forming a coarse, dense, and poorly conductive crystalline layer. This layer covers the surface of the active material and blocks the pores, leading to irreversible sulfation of the negative electrode and rapid capacity decay. Second, the repeated contraction and expansion of the active material volume caused by charge-discharge cycles causes microcracks to form inside the electrode plate and gradually expand. Ultimately, this leads to a decrease in the bonding force between the active material and the grid, and between different parts of the active material, and may even cause detachment, thus destroying the structural integrity of the electrode plate.

[0004] To improve the performance of negative electrode plates, existing technologies mainly involve adding carbon materials to construct a conductive network or introducing nucleating agents such as barium sulfate to induce uniform lead sulfate deposition. However, a single addition method cannot simultaneously solve the two core problems of electrochemical reaction kinetics and electrode plate structural stability. The interfacial bonding between carbon materials and active substances is weak, and they are prone to detachment after long-term cycling; traditional fiber additives have poor affinity with lead paste, making it difficult to truly play a role in reinforcing the framework.

[0005] To address the aforementioned problems, this invention provides a high-rate lead-acid battery negative electrode plate and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to provide a high-rate lead-acid battery negative electrode plate and its preparation method to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a negative electrode plate for a high-rate lead-acid battery includes the following steps: Step 1: Dry mix lead powder, barium sulfate, sodium lignosulfonate, polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, and hydrophilic modified polyester high-strength fiber; add deionized water and dilute sulfuric acid, stir to obtain negative electrode lead paste; coat the lead paste onto the negative electrode grid, and roll it with a roller press. Step 2: Curing the rolled negative electrode plate; obtaining a high-rate lead-acid battery negative electrode plate.

[0008] Furthermore, the negative electrode lead paste comprises the following components, by weight: 100 parts lead powder, 0.8-1.2 parts barium sulfate, 0.1-0.3 parts sodium lignosulfonate, 0.5-3 parts polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, 0.1-0.3 parts hydrophilic modified polyester high-strength fiber, 10-14 parts deionized water, and 8-12 parts dilute sulfuric acid.

[0009] Furthermore, the preparation method of the polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material is as follows: under ice bath conditions, the NS co-doped carbon nanotube-porous PbO-PbS composite material is dispersed in an ethanol aqueous solution to obtain a dispersion; 3-carboxylate pyrrole is added to the above dispersion and dispersed evenly; then, ammonium persulfate solution is added dropwise and thoroughly mixed and stirred; the mixture is filtered, washed, vacuum dried, ground, and sieved to obtain the polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material.

[0010] Furthermore, the preparation method of the NS co-doped carbon nanotube-porous PbO-PbS composite material is as follows: take carbon nanotubes, add a mixed solvent, and ultrasonically disperse for 20-30 min to obtain a carbon nanotube dispersion; add lead nitrate and thiazole-2,5-dicarboxylic acid sequentially to the carbon nanotube dispersion, stir for 30-40 min to obtain a mixed solution, perform hydrothermal reaction of the mixed solution for 20-24 h, cool, centrifuge, wash, and freeze-dry to obtain carbon nanotube@lead-based MOF composite aerogel; calcine at 500-550℃ for 3-4 h, cool, and grind evenly to obtain the NS co-doped carbon nanotube-porous PbO-PbS composite material.

[0011] Furthermore, the preparation method of the hydrophilic modified polyester high-strength fiber is as follows: polyethylene glycol diglycidyl ether is dissolved in deionized water, and the pH is adjusted with triethylamine to obtain a hydrophilic modification solution. The pretreated fiber is immersed in the hydrophilic modification solution and reacted at 60-75℃ for 90-100 min. After the reaction is completed, the fiber is taken out, washed thoroughly, and vacuum dried at 50-60℃ to obtain the hydrophilic modified polyester high-strength fiber.

[0012] Furthermore, the preparation method of the pretreated fiber is as follows: take high-strength polyester fiber, immerse it in sodium hydroxide aqueous solution, soak it at 60-70℃ for 10-20 minutes, cool, filter, wash, and vacuum dry at 50-60℃ to obtain the pretreated fiber.

[0013] Furthermore, the composition of the negative electrode grid is as follows, by mass fraction: calcium 0.12wt%-0.18wt%, tin 0.4wt%-0.6wt%, aluminum 0.01wt%-0.05wt%, with the balance being lead.

[0014] Furthermore, the specific parameters for curing the negative electrode plate are: curing at 40-50℃ for 22-24 hours.

[0015] Furthermore, the mass ratio of the carbon nanotubes, lead nitrate, and thiazole-2,5-dicarboxylic acid is 1:(8-12):(5-7).

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses carbon nanotubes as the negative electrode conductive additive matrix, effectively improving electrode reaction kinetics and active material utilization. Carbon nanotubes possess excellent conductivity, a high aspect ratio, and a hexagonal carbon ring connection structure, enabling the construction of a highly efficient three-dimensional electron transport network in the lead paste. This significantly reduces uneven current density distribution and electrode polarization during discharge, thereby reducing battery internal resistance. Simultaneously, the addition of carbon nanotubes increases the porosity of the lead paste, optimizing ion diffusion channels and allowing the active material to maintain high reversibility during deep charge-discharge processes, significantly improving lead paste utilization and charge acceptance. In the carbon nanotube-porous PbO-PbS composite material, the porous lead oxide originates from the pyrolysis transformation of the MOF framework, providing a high specific surface area and abundant reactive sites; the lead sulfide nanocrystals have a crystal structure that matches that of lead sulfate, and can serve as heterogeneous nucleation sites to induce lead sulfate to deposit in the form of fine and uniform particles, effectively suppressing negative electrode side reactions; the thiazole-2,5-dicarboxylic acid ligand simultaneously achieves in-situ doping of nitrogen and sulfur elements during pyrolysis, further improving the conductivity, hydrophilicity and interfacial bonding of the carbon material, and significantly extending the overall lifespan of the battery from an electrochemical perspective.

[0017] 2. This invention employs polyethylene glycol glycidyl ether to hydrophilically graft-modify high-strength polyester fibers, which are then added to the negative electrode lead paste, significantly enhancing the structural stability of the electrode plate. High-strength polyester fibers have a higher fiber count and specific surface area. The hydrophilic polyethylene glycol long chains introduced after graft modification further enhance the interfacial bonding strength through the weak coordination between ether oxygen atoms and lead ions, ensuring the electrode plate maintains structural integrity during long-term cycling, thereby increasing cycle count and battery life.

[0018] 3. The carboxyl groups densely distributed on the polypyrrole carboxylic acid molecular chain exhibit negative charge at the negative electrode working potential. Through electrostatic interaction, they can pre-enrich lead ions in the electrolyte, causing lead sulfate generated during discharge to preferentially deposit on the composite material surface, effectively inhibiting the formation of coarse crystalline layers. The polypyrrole carboxylic acid coating layer improves the dispersion stability of the carbon nanotube-porous PbO-PbS composite material in aqueous systems and optimizes the microstructure uniformity of the lead paste. The hydrophilicity of the polypyrrole carboxylic acid skeleton and its negative surface charge characteristics ensure that the composite material remains highly dispersed during lead paste preparation and sizing, resulting in a more uniform pore distribution within the lead paste, unobstructed ion transport channels, and enhanced active material reaction, thereby improving the capacity utilization and cycle stability of the negative electrode under high-rate charge-discharge conditions. Both polypyrrole carboxylic acid and the long polyethylene glycol chains on the modified fiber surface possess excellent hydrophilicity and coordination ability with lead ions. During lead paste curing and cycling, they can chemically react with active materials, effectively buffering volume changes during cycling and significantly extending the cycle life of the electrode plate during charge-discharge processes. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments, and all described quantities are by weight. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The sources and types of substances involved in this invention are not specifically limited. Exemplary examples include the following raw materials: carbon nanotubes: particle size: 9.5 nm, length: 1.5 μm. Available from Forsmann Technology (Beijing) Co., Ltd.; high-strength polyester fiber: type: TEX75D12F, available from Haining Taixin New Material Co., Ltd.; barium sulfate: type: YJ-002, available from Shanghai Yuanjiang Chemical Co., Ltd.; lead powder: purity ≥99.9%, particle size: 400 mesh, available from Shandong Xinbaiyi Metal Materials Co., Ltd.

[0021] The preparation process of 3-carboxylic acid pyrrole in Examples 1-3 and Comparative Examples 1-3 is as follows: Potassium hydroxide was added to a 500 mL ethanol solution containing 50 g of pyrrole, and the ethanol was evaporated at 60-65 °C. 200 mL of acetone was added, and 150 g of benzenesulfonyl chloride was slowly added dropwise under an ice bath. After the addition was complete, the mixture was reacted at 25-30 °C for 20-40 min. The mixture was then extracted, washed, separated, dried, filtered, and evaporated to dryness to obtain 1-(phenylsulfonyl)-1H-pyrrole. 100g of aluminum chloride and 500mL of 1,2-dichloroethane were mixed, 40g of acetyl chloride was added, and the mixture was stirred for 30min. A solution of 1,2-dichloroethane containing 50g of 1-(phenylsulfonyl)-1H-pyrrole was added dropwise. After the addition was complete, the mixture was reacted for 2h. The mixture was then cooled in an ice bath, extracted, separated, and evaporated to dryness to obtain 1-(1-(phenylsulfonyl)-1H-pyrrole-3-yl) ethyl ketone. 80 g of 1-(benzenesulfonyl)pyrrole-1H-3-carboxylic acid was dissolved in a mixture of 1200 mL of dioxane and 300 mL of water at 0 °C to obtain a mixed solution. 2000 g of elemental bromine was added dropwise to a 10 wt% sodium hydroxide solution at 0 °C to prepare a fresh sodium hypobromite solution. The sodium hypobromite solution was added dropwise to the mixed solution, and the mixture was stirred at 0 °C for 2 h. 400 mL of acetone was added, and the pH was adjusted to 1-1.5 with hydrochloric acid. The mixture was extracted and dried to obtain 1-(benzenesulfonyl)pyrrole-1H-3-carboxylic acid. 40 g of 1-(benzenesulfonyl)pyrrole-1H-3-carboxylic acid was dissolved in 200 mL of methanol, 150 mL of 16% sodium hydroxide solution was added, and the mixture was heated to 85 °C and refluxed for 4.5 h. The mixture was then rotary evaporated, and dilute hydrochloric acid was added to adjust the pH to 1. The mixture was filtered, dried, and recrystallized to obtain 3-carboxylic acid pyrrole. Example

[0022] Step 1: Preparation of polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material 0.33 g of carbon nanotubes were weighed and added to 60 mL of a mixed solvent consisting of anhydrous ethanol and deionized water in a volume ratio of 1.5:1. The mixture was ultrasonically dispersed for 20 min to obtain a carbon nanotube dispersion. 3 g of lead nitrate and 1.6 g of thiazole-2,5-dicarboxylic acid were added sequentially to the dispersion, and the mixture was stirred at room temperature for 30 min to obtain a mixed solution. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 170 °C for 20 h. After cooling, centrifugation, washing, and freeze-drying, a carbon nanotube@lead-based MOF composite aerogel was obtained. The aerogel was placed in a tube furnace and calcined at 500 °C for 3 h under argon protection. After cooling, it was ground uniformly to obtain an NS co-doped carbon nanotube-porous PbO-PbS composite material. Under ice bath conditions, 1.5 g of N-S co-doped carbon nanotube-porous PbO-PbS composite material was first dispersed at high speed in an ethanol aqueous solution to obtain a dispersion; wherein the mass ratio of ethanol to water in the ethanol aqueous solution was 1:3. 0.3 g of 3-carboxylic acid pyrrole was added to the above dispersion and dispersed evenly. Then, 75 mL of 0.03 g / mL ammonium persulfate solution was slowly added dropwise and thoroughly mixed and stirred. The mixture was filtered, washed, vacuum dried at 50 °C for 14 h, ground, sieved, and collected to obtain the polycarboxylic acid pyrrole-coated carbon nanotube-PbO-PbS composite material. Step 2: Preparation of hydrophilic modified high-strength polyester fibers Take 10g of high-strength polyester fiber and immerse it in a 5wt% sodium hydroxide aqueous solution. Soak it at 60℃ for 10min, cool, filter, wash, and vacuum dry at 50℃ to obtain pretreated fiber. Dissolve 8g of polyethylene glycol diglycidyl ether in 100g of deionized water and adjust the pH to 8.5 with triethylamine to obtain a hydrophilic modification solution. Immerse the pretreated fiber in the hydrophilic modification solution and react at 60℃ for 90min. After the reaction is complete, take out the fiber, wash it thoroughly, and vacuum dry at 50℃ to obtain hydrophilic modified high-strength polyester fiber. Step 3: High-rate lead-acid battery negative plate By weight, 100 parts lead powder, 0.8 parts barium sulfate, 0.1 parts sodium lignosulfonate, 0.5 parts polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, and 0.1 parts hydrophilic modified polyester high-strength fiber are dry-mixed for 5 min; 10 parts deionized water and 8 parts 1.4 g / mL dilute sulfuric acid are added, and the mixture is stirred for 10-15 min to obtain negative electrode lead paste; the lead paste is coated onto the negative electrode grid and rolled using a roller press; the mass ratio of each component of the negative electrode grid alloy is: calcium 0.16 wt%, tin 0.5 wt%, aluminum 0.02 wt%, with the balance being lead; the rolled negative electrode plate is cured at 40℃ for 22 h to obtain a high-rate lead-acid battery negative electrode plate. Example

[0023] Step 1: Preparation of polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material 0.33 g of carbon nanotubes were weighed and added to 60 mL of a mixed solvent consisting of anhydrous ethanol and deionized water in a volume ratio of 1.5:1. The mixture was ultrasonically dispersed for 25 min to obtain a carbon nanotube dispersion. 3 g of lead nitrate and 1.6 g of thiazole-2,5-dicarboxylic acid were added sequentially to the dispersion, and the mixture was stirred at room temperature for 35 min to obtain a mixed solution. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 170 °C for 22 h. After cooling, centrifugation, washing, and freeze-drying, a carbon nanotube@lead-based MOF composite aerogel was obtained. The aerogel was placed in a tube furnace and calcined at 520 °C for 3.5 h under argon protection. After cooling, the aerogel was ground uniformly to obtain an NS co-doped carbon nanotube-porous PbO-PbS composite material. Under ice bath conditions, 1.5 g of N-S co-doped carbon nanotube-porous PbO-PbS composite material was first dispersed at high speed in an ethanol aqueous solution to obtain a dispersion; wherein the mass ratio of ethanol to water in the ethanol aqueous solution was 1:3. 0.3 g of 3-carboxylic acid pyrrole was added to the above dispersion and dispersed evenly. Then, 75 mL of 0.03 g / mL ammonium persulfate solution was slowly added dropwise and thoroughly mixed and stirred. The mixture was then filtered, washed, and vacuum dried at 55 °C for 14-16 h. After grinding, sieving, and collection, the polycarboxylic acid pyrrole-coated carbon nanotube-PbO-PbS composite material was obtained. Step 2: Preparation of hydrophilic modified high-strength polyester fibers Take 10g of high-strength polyester fiber and immerse it in a 5wt% sodium hydroxide aqueous solution. Soak it at 65℃ for 15min, cool, filter, wash, and vacuum dry at 55℃ to obtain pretreated fiber. Dissolve 8g of polyethylene glycol diglycidyl ether in 100g of deionized water and adjust the pH to 8.8 with triethylamine to obtain a hydrophilic modification solution. Immerse the pretreated fiber in the hydrophilic modification solution and react at 70℃ for 95min. After the reaction is complete, take out the fiber, wash it thoroughly, and vacuum dry at 55℃ to obtain hydrophilic modified high-strength polyester fiber. Step 3: High-rate lead-acid battery negative plate By weight, 100 parts lead powder, 1 part barium sulfate, 0.2 parts sodium lignosulfonate, 2 parts polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, and 0.2 parts hydrophilic modified polyester high-strength fiber are dry-mixed for 8 min; 12 parts deionized water and 10 parts 1.4 g / mL dilute sulfuric acid are added and stirred for 12 min to obtain negative electrode lead paste; the lead paste is coated on the negative electrode grid and rolled using a roller press; the mass ratio of each component of the negative electrode grid alloy is: calcium 0.16 wt%, tin 0.5 wt%, aluminum 0.02 wt%, with the balance being lead; the rolled negative electrode plate is cured at 45℃ for 23 h to obtain a high-rate lead-acid battery negative electrode plate. Example

[0024] Step 1: Preparation of polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material 0.33 g of carbon nanotubes were weighed and added to 60 mL of a mixed solvent consisting of anhydrous ethanol and deionized water in a volume ratio of 1.5:1. The mixture was ultrasonically dispersed for 30 min to obtain a carbon nanotube dispersion. 3 g of lead nitrate and 1.6 g of thiazole-2,5-dicarboxylic acid were added sequentially to the dispersion, and the mixture was stirred at room temperature for 40 min to obtain a mixed solution. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 170 °C for 24 h. After cooling, centrifugation, washing, and freeze-drying, a carbon nanotube@lead-based MOF composite aerogel was obtained. The aerogel was placed in a tube furnace and calcined at 550 °C for 4 h under argon protection. After cooling, it was ground uniformly to obtain an NS co-doped carbon nanotube-porous PbO-PbS composite material. Under ice bath conditions, 1.5 g of N-S co-doped carbon nanotube-porous PbO-PbS composite material was first dispersed at high speed in an ethanol aqueous solution to obtain a dispersion; wherein the mass ratio of ethanol to water in the ethanol aqueous solution was 1:3. 0.3 g of 3-carboxylic acid pyrrole was added to the above dispersion and dispersed evenly. Then, 75 mL of 0.03 g / mL ammonium persulfate solution was slowly added dropwise and thoroughly mixed and stirred. The mixture was filtered, washed, vacuum dried at 60 °C for 16 h, ground, sieved, and collected to obtain the polycarboxylic acid pyrrole-coated carbon nanotube-PbO-PbS composite material. Step 2: Preparation of hydrophilic modified high-strength polyester fibers Take 10g of high-strength polyester fiber and immerse it in a 5wt% sodium hydroxide aqueous solution. Soak it at 70℃ for 20min, cool, filter, wash, and vacuum dry at 60℃ to obtain pretreated fiber. Dissolve 8g of polyethylene glycol diglycidyl ether in 100g of deionized water and adjust the pH to 9.0 with triethylamine to obtain a hydrophilic modification solution. Immerse the pretreated fiber in the hydrophilic modification solution and react at 75℃ for 100min. After the reaction is complete, take out the fiber, wash it thoroughly, and vacuum dry at 60℃ to obtain hydrophilic modified high-strength polyester fiber. Step 3: High-rate lead-acid battery negative plate By weight, 100 parts lead powder, 1.2 parts barium sulfate, 0.3 parts sodium lignosulfonate, 3 parts polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, and 0.3 parts hydrophilic modified polyester high-strength fiber are dry-mixed for 10 min; 14 parts deionized water and 12 parts 1.4 g / mL dilute sulfuric acid are added and stirred for 15 min to obtain negative electrode lead paste; the lead paste is coated on the negative electrode grid and rolled using a roller press; the mass ratio of each component of the negative electrode grid alloy is: calcium 0.16 wt%, tin 0.5 wt%, aluminum 0.02 wt%, with the balance being lead; the rolled negative electrode plate is cured at 40-50℃ for 24 h to obtain a high-rate lead-acid battery negative electrode plate.

[0025] Comparative Example 1: The NS co-doped carbon nanotube-porous PbO-PbS composite material without polycarboxylate pyrrole coating was the same as in Example 1.

[0026] Comparative Example 2: Without using the NS co-doped carbon nanotube-porous PbO-PbS composite material, carbon nanotubes were directly coated with polycarboxylate pyrrole, and the rest was the same as in Example 1. Comparative Example 3: No hydrophilic modification was performed on the polyester high-strength fiber, and the rest was the same as in Example 1.

[0027] experiment: Preparation of the positive electrode plate: All raw materials for the positive electrode lead paste are placed in a small paste mixer and dry-mixed for 30 minutes. The mixed lead paste is then coated onto the positive electrode grid. The wet plate is cured to obtain the positive electrode plate. The positive electrode paste formula is: 20 wt% red lead, 15 wt% sulfuric acid, 20 wt% water, 0.02 wt% polyester short fiber, and the balance is lead powder; the mass ratio of the components of the positive electrode grid alloy is: 0.08 wt% calcium, 1.1 wt% tin, 0.06 wt% aluminum, and the balance is lead. The negative electrode plate, positive electrode plate, and glass fiber cotton separator were filled with sulfuric acid aqueous solution electrolyte with a density of 1.325 g / cm3 to assemble a 12V, 12A lead-acid battery. High-rate performance tests were conducted. The high-rate battery cycle life of Examples 1-3 and Comparative Examples 1-3 was obtained by testing at 1C. The cycle ended when the cutoff voltage was lower than 1.75V. The test results are shown in Table 1.

[0028]

[0029] Conclusion: The data above shows that the high-rate lead-acid battery negative plate prepared by this invention has a cycle life of over 7800 cycles at 1C rate, indicating that it has excellent cycle stability and durability. In summary, the high-rate lead-acid battery negative plate prepared by this invention has both excellent high-rate cycle life and structural stability.

[0030] Comparative Example 1 did not use polycarboxylic acid pyrrole to coat the carbon nanotube-PbO-PbS composite material. The surface of the composite material in this negative electrode plate lacked carboxyl functional groups. Compared with Example 1, its 1C cycle life was significantly reduced. This indicates that the polycarboxylic acid pyrrole coating layer plays a key role in improving the interfacial affinity of the composite material and inhibiting the sulfation of the negative electrode through the nucleation induction and dispersion stabilization of carboxyl groups.

[0031] Comparative Example 2 did not construct a PbO-PbS heterostructure, but only used carbon nanotubes and polycarboxylic acid pyrrole coating. This negative electrode plate lacked nucleation sites that matched the lead sulfate lattice. Compared with Example 1, its 1C cycle life was significantly reduced, indicating that the PbO-PbS heterostructure can induce uniform deposition of lead sulfate through lattice matching, which can suppress the side reaction of irreversible sulfation of the negative electrode.

[0032] Comparative Example 3 did not undergo hydrophilic modification of the high-strength polyester fiber. The interfacial bonding force between the fiber and the active material in this negative electrode plate was weak. Compared with Example 1, its 1C cycle life decreased the most significantly. This indicates that polyethylene glycol graft modification, by introducing hydrophilic long chains and lead ion coordination ability, plays a decisive role in enhancing the interfacial bonding between the fiber and the active material and ensuring the long-term structural stability of the electrode plate.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a negative electrode plate for a high-rate lead-acid battery, characterized in that: Includes the following steps: Step 1: Dry mix lead powder, barium sulfate, sodium lignosulfonate, polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, and hydrophilic modified polyester high-strength fiber; add deionized water and dilute sulfuric acid, stir to obtain negative electrode lead paste; coat the lead paste onto the negative electrode grid, and roll it with a roller press. Step 2: Curing the rolled negative electrode plate; obtaining a high-rate lead-acid battery negative electrode plate.

2. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 1, characterized in that: The negative electrode lead paste comprises the following components, by weight: 100 parts lead powder, 0.8-1.2 parts barium sulfate, 0.1-0.3 parts sodium lignosulfonate, 0.5-3 parts polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material, 0.1-0.3 parts hydrophilic modified polyester high-strength fiber, 10-14 parts deionized water, and 8-12 parts dilute sulfuric acid.

3. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 1, characterized in that: The preparation method of the polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material is as follows: under ice bath conditions, the NS co-doped carbon nanotube-porous PbO-PbS composite material is dispersed in an ethanol aqueous solution to obtain a dispersion; 3-carboxylate pyrrole is added to the above dispersion and dispersed evenly; then, ammonium persulfate solution is added dropwise and thoroughly mixed and stirred; the mixture is filtered, washed, vacuum dried, ground, and sieved to obtain the polycarboxylate pyrrole-coated carbon nanotube-PbO-PbS composite material.

4. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 3, characterized in that: The preparation method of the NS co-doped carbon nanotube-porous PbO-PbS composite material is as follows: Take carbon nanotubes, add a mixed solvent, and ultrasonically disperse for 20-30 min to obtain a carbon nanotube dispersion; add lead nitrate and thiazole-2,5-dicarboxylic acid sequentially to the carbon nanotube dispersion, stir for 30-40 min to obtain a mixed solution, perform hydrothermal reaction of the mixed solution for 20-24 h, cool, centrifuge, wash, and freeze-dry to obtain carbon nanotube@lead-based MOF composite aerogel; calcine at 500-550℃ for 3-4 h, cool, and grind evenly to obtain the NS co-doped carbon nanotube-porous PbO-PbS composite material.

5. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 1, characterized in that: The preparation method of the hydrophilic modified high-strength polyester fiber is as follows: polyethylene glycol diglycidyl ether is dissolved in deionized water, and the pH is adjusted with triethylamine to obtain a hydrophilic modification solution. The pretreated fiber is immersed in the hydrophilic modification solution and reacted at 60-75℃ for 90-100 min. After the reaction is completed, the fiber is taken out, washed thoroughly, and vacuum dried at 50-60℃ to obtain the hydrophilic modified high-strength polyester fiber.

6. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 5, characterized in that: The method for preparing the pretreated fiber is as follows: take high-strength polyester fiber, immerse it in sodium hydroxide aqueous solution, soak it at 60-70℃ for 10-20 minutes, cool, filter, wash, and vacuum dry at 50-60℃ to obtain the pretreated fiber.

7. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 1, characterized in that: The negative electrode grid is composed of, by mass fraction: calcium 0.12-0.18 wt%, tin 0.4-0.6 wt%, aluminum 0.01-0.05 wt%, with the balance being lead.

8. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 1, characterized in that: The specific parameters for curing the negative electrode plate are: curing at 40-50℃ for 22-24 hours.

9. The method for preparing the negative electrode plate of a high-rate lead-acid battery according to claim 4, characterized in that: The mass ratio of the carbon nanotubes, lead nitrate and thiazole-2,5-dicarboxylic acid is 1:(8-12):(5-7).

10. A high-rate lead-acid battery negative electrode plate prepared by the method for preparing a high-rate lead-acid battery negative electrode plate according to any one of claims 1-9.

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