Preparation method and application of high specific capacitance lead-acid battery positive electrode lead paste

Abstract

The present invention provides a preparation method and application of a high-specific-capacity lead-acid battery positive electrode lead paste. The positive electrode lead paste is prepared from the following components in parts by weight: 980-1040 parts of lead powder, 85-100 parts of dilute sulfuric acid, 105-120 parts of deionized water, 1.5-3 parts of a composite electrode material, 0.8-1.4 parts of an antimony compound, 0.6-1.2 parts of a metal sulfate, 38-44 parts of lead oxide, and 0.7-1.0 parts of polyester fiber. By optimizing the lead paste formula, the conductivity and specific capacitance of the lead paste are improved, thereby extending the cycle life of the battery.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid batteries, and in particular relates to a preparation method and application of a positive electrode lead paste for a high-specific-capacity lead-acid battery. Background Art

[0002] Lead-acid batteries, with their significant advantages such as low cost, high safety, mature technology, good high and low temperature performance, and high current discharge capability, are widely used in automobile starting power supplies, uninterruptible power supplies (UPS), electric bicycle power sources, and various energy storage systems. For example, in the automotive field, lead-acid batteries are a key component of the vehicle's starting and power supply systems, providing the necessary power support for normal vehicle operation. In the communications field, lead-acid batteries in UPS ensure the continued operation of communication equipment during mains power outages, ensuring the stability and reliability of communications.

[0003] Patent application CN107634209A discloses a positive electrode lead paste for lead-acid batteries. The paste comprises the following components by weight: 75-85 parts lead powder, 10-20 parts sulfuric acid, 8-15 parts deionized water, 0.5-1.5 parts carbon nanofibers, 0.1-1.2 parts polyacrylic acid, and 0.05-0.15 parts polytetrafluoroethylene. This patent application improves the cold-cranking performance of lead-acid batteries through an optimized combination of multiple additives.

[0004] However, with the rapid development of new energy technologies and increasingly stringent battery performance requirements across various industries, traditional lead-acid batteries face significant challenges. Specific capacitance, a key indicator of battery performance, directly impacts the battery's charge and discharge efficiency and energy storage capacity. A high specific capacitance means the battery can store more charge per unit mass or volume, enabling faster conversion of electrical energy into chemical energy during charge and discharge, improving the device's operating efficiency and battery life.

[0005] Traditional lead paste for the positive electrode of lead-acid batteries mainly uses a lead paste material formed by the reaction of lead powder and sulfuric acid. Although the process is mature, it still has the following problems: Insufficient conductivity: The microstructure of traditional lead paste is relatively dense, and the conductivity of the active material is low, which leads to limited specific capacity of the plate and reduces the energy density of the battery; Limited cycle life: The lead paste is prone to structural expansion and shedding during the charge and discharge cycle, resulting in loss of active material on the plate, which in turn affects the long-term stability of the battery; Low specific capacitance: When the lead-acid battery is discharged at a high rate, the utilization rate of the active material is low, which makes it difficult to meet the needs of high-power energy storage applications.

[0006] Patent application publication number CN117219733A discloses a long-cycle-life lead-acid battery positive electrode and its preparation method. The long-cycle-life lead-acid battery positive electrode comprises the following raw materials, by weight: 5%-10% dilute sulfuric acid, 5%-20% deionized water, 0.1%-0.5% carbon fiber, 0.05%-0.5% conductive additive, 0.05%-0.5% bismuth oxide, 0.05%-0.5% structural stabilizing additive, 0.1%-5% seed additive, 2%-20% red lead, and the remainder being lead powder. The invention incorporates a seed additive into the lead paste to provide seeds for the formation of 4BS, promoting more uniform mixing. The addition of a conductive additive to the lead paste improves charge acceptance. The structural stabilizing additive in the lead paste stabilizes the paste during cycling, preventing softening and extending the cycle life.

[0007] Although there are many studies in the prior art on improving the conductivity and cycle stability of lead paste of lead-acid batteries by using additives, there is still room for improvement in the energy storage performance and cycle life of lead-acid batteries. Summary of the Invention

[0008] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a preparation method and application of high-specific-capacitance lead paste for positive electrodes of lead-acid batteries. By optimizing the lead paste formula, the conductivity and specific capacitance of the lead paste are improved, thereby extending the cycle life of the battery.

[0009] The present invention provides a method for preparing a positive electrode lead paste for a high specific capacitance lead-acid battery, wherein the positive electrode lead paste is prepared from the following components in parts by mass:

[0010] 980-1040 parts of lead powder, 85-100 parts of dilute sulfuric acid, 105-120 parts of deionized water, 1.5-3 parts of composite electrode material, 0.8-1.4 parts of antimony compound, 0.6-1.2 parts of metal sulfate, 38-44 parts of lead oxide, and 0.7-1.0 parts of polyester fiber.

[0011] Preferably, the density of the dilute sulfuric acid is 1.3-1.6 g / mL.

[0012] Preferably, the polyester fiber is quinoline-modified polyethylene terephthalate (PET) fiber. The polyester fiber is prepared by placing 105-130 parts by mass of PET fiber in 1200-2000 parts by mass of ethylene dichloride, stirring uniformly, and then adding 0.2-0.66 parts by mass of zinc chloride as a catalyst. Then, 3.5-6 parts by mass of 2,3-quinolinedicarboxylic anhydride are added to carry out an acylation reaction to obtain the quinoline-modified PET fiber. The introduction of quinoline structures into the polyester fiber imparts excellent properties such as antioxidant and UV resistance, improving stability and durability. Furthermore, the surface polarity and chemical properties of the polyester fiber are altered, enhancing compatibility with the lead paste components and facilitating dispersion.

[0013] Acylation reaction mechanism: The zinc chloride catalyst coordinates with the carbonyl oxygen of 2,3-quinolinedicarboxylic anhydride to enhance the positive charge of the carbonyl carbon; the carbonyl carbon of the activated 2,3-quinolinedicarboxylic anhydride attacks the benzene ring of the polyethylene terephthalate fiber, undergoing electrophilic substitution, and the hydrogen leaves as a proton to form quinoline-modified polyethylene terephthalate fiber.

[0014] More preferably, the acylation reaction temperature is 58-65°C, and the reaction time is 4.5-6 hours. Even more preferably, the acylation reaction temperature is 65°C, and the reaction time is 6 hours.

[0015] Preferably, the method for preparing the composite electrode material comprises the following steps:

[0016] S1: acid-washing 12-20 parts by mass of carbon nanotubes to remove surface impurities, then washing to neutrality, and drying;

[0017] S2: Place the carbon nanotubes obtained in step S1 into a reaction vessel, add 100-150 parts by mass of a 0.1-0.2M Mn(NO3)2 aqueous solution, and stir to mix; then dropwise add 100-120 parts by mass of a 0.06-0.1M KMnO4 aqueous solution, while stirring, and react to obtain a product;

[0018] S3: The product obtained in step S2 is washed to neutrality, and then heated at 130-160° C. for 6-10 hours. After the product is cooled to room temperature, it is washed to remove surface residues and dried to obtain the composite electrode material.

[0019] Further preferably, in step S2, when the KMnO4 aqueous solution is added dropwise, the dropping speed is controlled at 1-2 mL / min, the reaction temperature is 65-80°C, the reaction time is 2.5-4 hours, and after the reaction, the product is allowed to stand for 8-12 hours.

[0020] Further preferably, in step S3, during washing, deionized water is first used for washing 3-5 times, and then washed with ethanol.

[0021] Preferably, the antimony compound is at least one of antimony trioxide, antimony pentoxide and sodium antimonate; the metal sulfate is at least one of stannous sulfate, zinc sulfate and magnesium sulfate; and the lead oxide is at least one of lead tetroxide and lead oxide.

[0022] The present invention also provides a high-capacity lead-acid battery positive electrode lead paste prepared by the preparation method.

[0023] The present invention also provides a high-capacity lead-acid battery positive electrode plate, comprising a positive electrode grid and a positive electrode lead paste coated on the positive electrode grid, wherein the positive electrode lead paste is the high-capacity lead-acid battery positive electrode lead paste.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Improvement of specific capacitance: Improve the microstructure and conductivity of the positive electrode lead paste, form a conductive network, increase the electrode-electrolyte contact area, and improve the specific capacitance.

[0026] (2) Improved charge and discharge performance: The positive lead paste of the present invention makes the battery charge and discharge efficiency higher and the voltage output more stable.

[0027] (3) Enhanced electrode stability: Polyester fiber is resistant to oxidation and has good durability, which maintains the integrity of the positive electrode lead paste structure, reduces electrode expansion and shedding, and extends battery life. DETAILED DESCRIPTION

[0028] Example 1

[0029] 1. Formula composition of positive lead paste:

[0030] 980 g lead powder, 85 g dilute sulfuric acid (density of dilute sulfuric acid is 1.3 g / mL), 105 g deionized water, 1.5 g composite electrode material, 0.8 g antimony pentoxide, 1.2 g zinc sulfate, 38 g lead tetroxide, and 0.7 g quinoline-modified polyester fiber (length 1.0 mm, diameter 15 μm).

[0031] 2. Preparation of composite electrode materials:

[0032] S1: 12 g of carbon nanotubes were placed in 55 g of mixed acid, ultrasonicated at 50 °C for 3 h to remove surface impurities, thoroughly washed until neutral, and then vacuum dried for 10 h; the mixed acid was a concentrated nitric acid / sulfuric acid (1:3, v / v) solution with a 65 wt% nitric acid concentration and a 98 wt% sulfuric acid concentration, the same below;

[0033] S2: Add 100 g of 0.15 M Mn(NO3)2 aqueous solution to the reaction vessel containing the treated carbon nanotubes, stir and disperse, and add 100 g of 0.08 M KMnO4 dropwise at a rate of 1.5 mL / min while maintaining a stirring speed of 350 rpm, a reaction temperature of 70 °C, and a reaction time of 3 h. After the reaction, let the product stand for 8 hours.

[0034] S3: The product was washed with deionized water until the pH of the washing solution was 7, and then transferred to a hydrothermal reactor with a reaction temperature of 140°C and a reaction time of 9 h. After the reaction product was cooled to room temperature, it was first washed with deionized water three times, then washed with ethanol, and dried to obtain the composite electrode material.

[0035] 3. Preparation of quinoline modified polyester fiber:

[0036] K1: Place 110 g of PET fiber in 1500 g of dichloroethane, stir evenly, add 0.3 g of ZnCl2, heat to 60 °C, slowly add 4 g of 2,3-quinolinedicarboxylic anhydride, and react for 5 h with continuous stirring;

[0037] K2: After the reaction is completed, the fiber is filtered, washed thoroughly with deionized water to remove unreacted substances, and dried to obtain quinoline-modified polyethylene terephthalate fiber.

[0038] 4. Positive electrode lead paste preparation process:

[0039] Step 1: Accurately weigh the ingredients in parts by mass, add the weighed lead powder, composite electrode material, antimony pentoxide, zinc sulfate, and quinoline-modified polyester fiber into a paste mixer, then add the formulated amount of lead tetroxide, close the paste mixer's sealing cover, and then accurately weigh the formulated amount of lead powder through the paste mixer's lead powder delivery pipe and add it to the paste mixer, start mixing and stirring, and dry mix and stir for 7 minutes to ensure uniform mixing;

[0040] Step 2: Add deionized water three times, with the mass of deionized water added three times being 40%, 30% and 30% of the formula amount respectively, with an interval of 1.5 minutes between each addition;

[0041] Step 3: Slowly add dilute sulfuric acid three times, with the mass of dilute sulfuric acid added three times being 40%, 20% and 40% of the formula amount respectively, and the total acid addition time is 15 minutes;

[0042] Step 4: Measure the apparent specific gravity of the lead paste and ensure it is 4.38 g / cm³. Otherwise, adjust the apparent specific gravity to the specified requirement with deionized water. During the entire lead paste preparation process, the peak temperature should be controlled below 72°C, and the paste outlet temperature should be below 48°C.

[0043] Example 2

[0044] 1. Formula composition of positive lead paste:

[0045] 1020 g lead powder, 95 g dilute sulfuric acid (density of dilute sulfuric acid is 1.4 g / mL), 115 g deionized water, 2.5 g composite electrode material, 1.2 g sodium antimonate, 0.6 g magnesium sulfate, 42 g lead oxide, 0.9 g quinoline-modified polyester fiber (length 0.8 mm, diameter 18 μm).

[0046] 2. Preparation of composite electrode materials:

[0047] S1: 18 g of carbon nanotubes were placed in 58 g of mixed acid, ultrasonicated at 55 °C for 2.5 h to remove surface impurities, washed thoroughly to neutrality, and then vacuum dried for 9 h;

[0048] S2: Add 120 g of 0.18 M Mn(NO3)2 aqueous solution to the reaction vessel containing the treated carbon nanotubes, stir and disperse, and add 110 g of 0.07 M KMnO4 dropwise at a rate of 1.8 mL / min while maintaining a stirring speed of 400 rpm. The reaction temperature is 65 °C and the reaction time is 3.5 h. After the reaction, the product is allowed to stand for 9 hours.

[0049] S3: The product was washed with deionized water until the pH of the washing solution was 7, and then transferred to a hydrothermal reactor with a reaction temperature of 150°C and a reaction time of 8 h. After the reaction product was cooled to room temperature, it was first washed with deionized water 5 times, then washed with ethanol, and dried to obtain the composite electrode material.

[0050] 3. Preparation of quinoline modified polyester fiber:

[0051] K1: Place 125 g of PET fiber in 1800 g of dichloroethane, stir evenly, add 0.5 g of ZnCl2, heat to 58 °C, slowly add 5 g of 2,3-quinolinedicarboxylic anhydride, and react for 4.5 h with continuous stirring;

[0052] K2: After the reaction is completed, the fiber is filtered, washed thoroughly with deionized water to remove unreacted substances, and dried to obtain quinoline-modified polyethylene terephthalate fiber.

[0053] 4. Positive electrode lead paste preparation process:

[0054] Step 1: Accurately weigh the ingredients in parts by mass, add the weighed lead powder, composite electrode material, sodium antimonate, magnesium sulfate, and quinoline-modified polyester fiber into a paste mixer, then add the formulated amount of lead oxide, close the paste mixer's sealing cover, and then accurately weigh the formulated amount of lead powder through the paste mixer's lead powder delivery pipe and add it to the paste mixer, start mixing and stirring, and dry mix and stir for 6 minutes to ensure uniform mixing;

[0055] Step 2: Add deionized water three times, with the mass of deionized water added three times being 45%, 25% and 30% of the formula amount respectively, with an interval of 2 minutes between each addition;

[0056] Step 3: Slowly add dilute sulfuric acid three times. The mass of dilute sulfuric acid added three times is 38%, 22% and 40% of the formula respectively. The total acid addition time is 17 minutes.

[0057] Step 4: Measure the apparent specific gravity of the lead paste and find it is 4.42 g / cm³. Otherwise, adjust the apparent specific gravity to the specified requirement with deionized water. During the entire lead paste preparation process, the peak temperature should be controlled below 73°C, and the paste outlet temperature should be below 49°C.

[0058] Example 3

[0059] 1. Formula composition of positive lead paste:

[0060] 1000 g lead powder, 90 g dilute sulfuric acid (density of dilute sulfuric acid is 1.5 g / mL), 110 g deionized water, 2.0 g composite electrode material, 1.0 g antimony trioxide, 1.0 g stannous sulfate, 40 g lead tetroxide, and 0.8 g quinoline-modified polyester fiber (length 1.2 mm, diameter 12 μm).

[0061] 2. Preparation of composite electrode materials:

[0062] S1: 15 g of carbon nanotubes were placed in 53 g of mixed acid, ultrasonicated at 58 °C for 3.5 h to remove surface impurities, washed thoroughly to neutrality, and then vacuum dried for 11 h;

[0063] S2: Add 140 g of 0.12 M Mn(NO3)2 aqueous solution to the reaction vessel containing the treated carbon nanotubes, stir and disperse, and add 110 g of 0.06 M KMnO4 dropwise at a rate of 1.2 mL / min while maintaining a stirring speed of 380 rpm. The reaction temperature was 75 °C and the reaction time was 2.5 h. After the reaction, the product was allowed to stand for 10 hours.

[0064] S3: The product was washed with deionized water until the pH of the washing solution was 7, and then transferred to a hydrothermal reactor with a reaction temperature of 130°C and a reaction time of 10 h. After the reaction product was cooled to room temperature, it was first washed with deionized water 5 times, then washed with ethanol, and dried to obtain the composite electrode material.

[0065] 3. Preparation of quinoline modified polyester fiber:

[0066] K1: Place 105 g of PET fiber in 1200 g of dichloroethane, stir evenly, add 0.2 g of ZnCl2, heat to 62 °C, slowly add 3.5 g of 2,3-quinolinedicarboxylic anhydride, and react for 5.5 h with continuous stirring;

[0067] K2: After the reaction is completed, the fiber is filtered, washed thoroughly with deionized water to remove unreacted substances, and dried to obtain quinoline-modified polyethylene terephthalate fiber.

[0068] 4. Positive electrode lead paste preparation process:

[0069] Step 1: Accurately weigh the ingredients in parts by mass, add the weighed lead powder, composite electrode material, antimony trioxide, stannous sulfate, and quinoline-modified polyester fiber into a paste mixer, then add the formulated amount of lead tetroxide, close the paste mixer's sealing cover, and then accurately weigh the formulated amount of lead powder through the paste mixer's lead powder delivery pipe and add it to the paste mixer, begin mixing and stirring, and dry mix and stir for 5.5 minutes to ensure uniform mixing;

[0070] Step 2: Add deionized water three times, with the mass of deionized water added three times being 35%, 30% and 35% of the formula amount respectively, with an interval of 1.8 minutes between each addition;

[0071] Step 3: Slowly add dilute sulfuric acid three times. The mass of dilute sulfuric acid added three times is 42%, 18% and 40% of the formula respectively. The total acid addition time is 14 minutes.

[0072] Step 4: Measure the apparent specific gravity of the lead paste and ensure it is 4.40 g / cm³. Otherwise, adjust the apparent specific gravity to the specified requirement with deionized water. During the entire lead paste preparation process, the peak temperature should be controlled below 71°C, and the paste outlet temperature should be below 47°C.

[0073] Example 4

[0074] 1. Formula composition of positive lead paste:

[0075] 1040 g lead powder, 100 g dilute sulfuric acid (density of dilute sulfuric acid is 1.6 g / mL), 120 g deionized water, 3.0 g composite electrode material, 1.4 g antimony trioxide / sodium antimonate combination (0.8 g + 0.6 g), 0.8 g stannous sulfate / magnesium sulfate combination (0.5 g + 0.3 g), 44 g lead tetroxide / lead oxide combination (25 g + 19 g), 1.0 g quinoline-modified polyester fiber (length 0.6 mm, diameter 20 μm).

[0076] 2. Preparation of composite electrode materials:

[0077] S1: 20 g of carbon nanotubes were placed in 60 g of mixed acid, ultrasonicated at 60 °C for 4 h to remove surface impurities, washed thoroughly to neutrality, and then vacuum dried for 8 h;

[0078] S2: Add 150 g of 0.2 M Mn(NO3)2 aqueous solution to the reaction vessel containing the treated carbon nanotubes, stir and disperse, and add 120 g of 0.1 M KMnO4 dropwise at a rate of 2 mL / min while maintaining a stirring speed of 450 rpm. The reaction temperature is 80 °C and the reaction time is 4 h. After the reaction, the product is allowed to stand for 12 hours.

[0079] S3: The product was washed with deionized water until the pH of the washing solution was 7, and then transferred to a hydrothermal reactor with a reaction temperature of 160°C and a reaction time of 6 h. After the reaction product was cooled to room temperature, it was first washed with deionized water 5 times, then washed with ethanol, and dried to obtain the composite electrode material.

[0080] 3. Preparation of quinoline modified polyester fiber:

[0081] K1: Place 130 g of PET fiber in 2000 g of dichloroethane, stir evenly, add 0.66 g of ZnCl2, heat to 65 °C, slowly add 6 g of 2,3-quinolinedicarboxylic anhydride, and react for 6 h with continuous stirring;

[0082] K2: After the reaction is completed, the fiber is filtered, washed thoroughly with deionized water to remove unreacted substances, and dried to obtain quinoline-modified polyethylene terephthalate fiber.

[0083] 4. Positive electrode lead paste preparation process:

[0084] Step 1: Accurately weigh the ingredients in parts by mass, add the weighed lead powder, composite electrode material, antimony trioxide / sodium antimonate combination, stannous sulfate / magnesium sulfate combination, and quinoline-modified polyester fiber into a paste mixer, then add the formulated amount of lead tetroxide / lead oxide combination, close the paste mixer's sealing cover, and then accurately weigh the formulated amount of lead powder through the paste mixer's lead powder delivery pipe and add it to the paste mixer, start mixing and stirring, and dry mix and stir for 8 minutes to ensure uniform mixing;

[0085] Step 2: Add deionized water three times, with the mass of deionized water added three times being 50%, 30% and 20% of the formula amount respectively, with an interval of 1 minute each time;

[0086] Step 3: Slowly add dilute sulfuric acid three times, with the mass of dilute sulfuric acid added three times being 45%, 25% and 30% of the formula respectively, and the total acid addition time is 18 minutes;

[0087] Step 4: Measure the apparent specific gravity of the lead paste and ensure it is 4.45 g / cm³. Otherwise, adjust the apparent specific gravity to the specified requirement with deionized water. During the entire lead paste preparation process, the peak temperature should be controlled below 74°C, and the paste outlet temperature should be below 50°C.

[0088] Comparative Example 1

[0089] The difference between this example and Example 1 is that the composite electrode material in the lead paste preparation process is replaced by an equal amount of carbon nanotubes.

[0090] Comparative Example 2

[0091] The difference between this example and Example 1 is that the quinoline-modified polyester fiber in the lead paste preparation process is replaced by an equal amount of polyester fiber.

[0092] Test Example 1

[0093] The test method is as follows:

[0094] 1. Electrode specific capacitance test

[0095] 1.1 Preparation of working electrode: The positive lead pastes of different examples and comparative examples were coated on a lead mesh (area 1 cm²), dried at 60°C for 24 h and then used. The prepared working electrode was combined with a commercial negative electrode plate to form a battery system and immersed in 1.08 g / cm 3 The formation is carried out in a sulfuric acid solution. The formation time is 24 h and the formation charge current density is 3~5 mA / cm 2 After the formation is completed, the working electrode should be thoroughly washed and dried.

[0096] 1.2 Assembled using a three-electrode system

[0097] Reference electrode: Mercury-mercurous sulfate electrode (SCE), Counter electrode: Platinum sheet. Test electrolyte: 1.28 g / cm³ H₂SO₄ solution.

[0098] 1.3 The specific capacitance was measured using the galvanostatic charge-discharge (GCD) method at a current density of 1.0 A / g and a voltage range of 0–1.2 V. The specific capacitance, C (F / g), was calculated as: C = I·Δt / m·ΔV, where I is the discharge current, Δt is the discharge time, m is the mass of the active material, and ΔV is the discharge potential window.

[0099] 2. Charge and discharge cycle life test

[0100] A two-electrode system was used, with the negative electrode prepared from the same mass and ratio of negative lead paste. A 2 V lead-acid battery cell was assembled, and the test electrolyte was a 1.28 g / cm³ H₂SO₄ solution. Cycle life testing was performed using constant current charge and discharge (0.2C, cut-off voltage 1.8 V), recording the number of cycles required to retain 80% of the capacity.

[0101] 3. Charge and discharge efficiency test

[0102] Calculate the Coulombic efficiency of battery charge and discharge: η=Q discharge / Q charge ×100%. Among them, Q discharge is the discharge capacity, Q charge is the charging capacity.

[0103] Table 1 Test results

[0104]

[0105] The test results are shown in Table 1. The high specific capacitance lead-acid battery positive electrode lead paste provided by Examples 1-4 of the present invention, based on manganese dioxide / three-dimensional carbon-based composite materials and quinoline-modified polyester fibers, significantly improves the energy storage performance and cycle life of lead-acid batteries and has good application prospects.

Claims

1. A method for preparing a positive electrode lead paste for a high specific capacitance lead-acid battery, characterized in that: The high specific capacitance lead-acid battery positive electrode lead paste is prepared from the following components in parts by mass: 980-1040 parts of lead powder, 85-100 parts of dilute sulfuric acid, 105-120 parts of deionized water, 1.5-3 parts of composite electrode material, 0.8-1.4 parts of antimony compound, 0.6-1.2 parts of metal sulfate, 38-44 parts of lead oxide, and 0.7-1.0 parts of polyester fiber; The composite electrode material is a manganese dioxide / three-dimensional carbon-based composite material; The polyester fiber is quinoline-modified polyethylene terephthalate fiber, and the preparation method of the polyester fiber is as follows: 105-130 parts by mass of polyethylene terephthalate fiber are placed in 1200-2000 parts by mass of ethylene dichloride, stirred evenly, and then 0.2-0.66 parts by mass of zinc chloride catalyst are added; 3.5-6 parts by mass of 2,3-quinolinedicarboxylic anhydride is added to carry out acylation reaction to obtain quinoline-modified polyethylene terephthalate fiber.

2. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 1, wherein: The density of the dilute sulfuric acid is 1.3-1.6 g / mL.

3. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 1, wherein: The acylation reaction temperature is 58-65°C, and the reaction time is 4.5-6 hours.

4. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 1, wherein: The preparation method of the composite electrode material comprises the following steps: S1: acid-washing 12-20 parts by mass of carbon nanotubes to remove surface impurities, then washing to neutrality, and drying; S2: Place the carbon nanotubes obtained in step S1 into a reaction vessel, add 100-150 parts by mass of a 0.1-0.2 M Mn(NO3)2 aqueous solution, and stir to mix; then dropwise add 100-120 parts by mass of a 0.06-0.1 M KMnO4 aqueous solution, while stirring, and react to obtain a product; S3: The product obtained in step S2 is washed to neutrality, and then heated at 130-160° C. for 6-10 hours. After the product is cooled to room temperature, it is washed to remove surface residues and dried to obtain the composite electrode material.

5. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 4, wherein: In step S2, when the KMnO4 aqueous solution is added dropwise, the addition rate is controlled at 1-2 mL / min, the reaction temperature is 65-80°C, and the reaction time is 2.5-4 hours. After the reaction, the product is allowed to stand for 8-12 hours.

6. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 4, wherein: In step S3, during washing, first use deionized water to wash 3-5 times, and then wash with ethanol.

7. The method for preparing a positive lead paste for a high specific capacitance lead-acid battery according to claim 1, wherein: The antimony compound is at least one of antimony trioxide, antimony pentoxide and sodium antimonate; The metal sulfate is at least one of stannous sulfate, zinc sulfate and magnesium sulfate; The lead oxide is at least one of trilead tetroxide and lead oxide.

8. A high specific capacitance lead-acid battery positive electrode lead paste prepared by the preparation method according to any one of claims 1 to 7.

9. A positive electrode plate for a high specific capacitance lead-acid battery, comprising a positive electrode grid and a positive lead paste coated on the positive electrode grid, characterized in that: The positive electrode paste is the high specific capacitance lead-acid battery positive electrode paste according to claim 8.

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