Positive electrode lead paste with high active substance utilization rate and preparation method of positive electrode lead paste

Abstract

The invention discloses positive lead paste with high active substance utilization rate and a preparation method thereof, and relates to the technical field of positive lead paste of lead storage batteries. The positive lead paste comprises 100 parts of lead powder, 6 to 8 parts of red lead, 0.1 to 0.2 part of graphite, 0.1 to 0.2 part of stannous mono-sulphate, 0.05 to 1 part of antimony trioxide, 0.2 to 0.8 part of short fiber, 0.1 to 0.2 part of sulfonic polythiophene derivative additive, 5 to 15 parts of sulfuric acid and 1 to 10 parts of water. By adding the sulfo polythiophene derivative as an additive, the prepared positive lead paste has good electrochemical oxidation-reduction performance, and can promote the improvement of the conversion efficiency of positive active substances, effectively reduce the resistance of a lead-acid battery, improve the initial performance of the lead-acid battery and prolong the cycle life of the lead-acid battery when being applied to the lead-acid battery; and contributions are made to the development of lead-acid batteries.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of positive lead paste of lead-acid battery, and particularly relates to a positive lead paste with high active material utilization rate and a preparation method thereof. BACKGROUND

[0002] Lead-acid batteries are widely used in the fields of automobile, electric vehicle, communication and power transmission due to high safety, low cost, recyclable raw materials and other advantages, but the market competitiveness gradually decreases due to the low energy density. At present, the discharge capacity of the positive plate of the lead-acid battery is much lower than that of the negative plate. Therefore, improving the utilization rate of the positive active material (PAM) is the key to improving the energy density of the lead-acid battery. In essence, the utilization rate of the PAM is limited by factors such as ion / electron transmission characteristics, interface structure, active site density participating in electrochemical reaction, contact area with electrolyte and ion diffusion distance. In particular, the interface corrosion layer connecting the PAM and the grid is usually a high-impedance lead oxide layer, which makes the lead-acid battery prone to early capacity loss (PCL) and quickly fails. In addition, the PAM constantly expands and shrinks during the charging and discharging process, which makes the bonding force between the PAM and the grid and between the PAMs poor, thereby causing the softening and falling off of the PAM and ultimately shortening the cycle life of the battery.

[0003] According to the existing lead-acid battery production process and formula (lead powder, sulfuric acid, water, red lead, short fiber), the conventional formula limits the further improvement of the active material utilization rate of the positive lead paste, and therefore, it is necessary to provide a positive additive for improving the active material utilization rate of the positive plate of the lead-acid battery, to further improve the active material utilization rate of the positive lead paste, reduce the cost of battery materials, improve the performance of the battery and improve the comprehensive market competitiveness of the lead-acid battery product. SUMMARY

[0004] One of the purposes of the present application is to provide a positive lead paste with high active material utilization rate to solve the problem of low conversion efficiency of positive active material of the lead-acid battery during use. The second purpose of the present application is to provide a preparation method of the positive lead paste with high active material utilization rate.

[0005] The purpose of the present application can be achieved by the following technical solutions. A positive lead paste with high active material utilization rate, according to weight parts, comprises the following components: Lead powder 100 parts, red lead 6-8 parts, graphite 0.1-0.2 parts, stannous sulfate 0.1-0.2 parts, antimony trioxide 0.05-1 parts, short fiber 0.2-0.8 parts, sulfonic acid-based polythiophene derivative additive 0.1-0.2 parts, sulfuric acid 5-15 parts, and water 1-10 parts.

[0006] Further, the preparation method of the sulfonic acid group polythiophene derivative additive comprises the following steps: S1. Under N2 conditions, 2,5-dibromo-3-(methylsulfonyl) thiophene (CAS: 2926693-10-7) is added to DMAC (N,N-dimethylacetamide), then Ni (COD)2 (bis(1,5-cyclooctadiene) nickel (0)) and 1,3-bisdiphenylphosphinopropane (DPPP) are added, then molecular sieves are added, the mixture is left to stand at room temperature (25-30°C) for 1-4h, and then the molecular sieves are separated to obtain a mixture; S2. The mixture is placed under the conditions of 60-100°C and 600-1200rpm for 24-86h, and propanol is added to precipitate the reactants during the reaction; after the reaction is completed, centrifugation, washing and vacuum drying are sequentially performed to obtain the sulfonic acid group polythiophene derivative additive.

[0007] Under the catalysis of zero-valent nickel, 2,5-dibromo-3-(methylsulfonyl) thiophene undergoes oxidative coupling polymerization, the C-Br bond of the monomer is activated by the catalyst, the thiophene ring is connected to form a long-chain polymer through a C-C bond, and the methylsulfonyl group remains stable during the polymerization process (it can be converted into a sulfonic acid group by subsequent hydrolysis to improve hydrophilicity); the molecular sieves can deeply dehydrate to ensure the stability of the catalytic system; the polythiophene derivative is a rigid conjugated polymer with high solubility in strong polar DMAC, but the solubility in weak polar propanol decreases sharply (the difference in solvent polarity causes the polymer chain to aggregate and precipitate). The addition of propanol can quickly separate the polymer from the reaction system, avoiding the generation of by-products by the continued reaction of the polymer with unreacted monomers / catalysts; after repeated centrifugation and washing, a polymer with high conductivity is finally obtained.

[0008] Further, in S1, the molar ratio of 3-sulfonic acid group-2,5-dibromothiophene, Ni (COD)2 and 1,3-bisdiphenylphosphinopropane is (0.01-0.1) mol:(0.0001-0.001) mol:0.00005-0.0005 mol. Under this ratio, the ligand DPPP coordinates with Ni (0) in a specific proportion, avoiding the deactivation of free Ni (0) and reducing the excessive amount of ligand leading to coordination saturation.

[0009] Preferably, in S1, the molar ratio of 3-sulfonic acid group-2,5-dibromothiophene, Ni (COD)2 and 1,3-bisdiphenylphosphinopropane is (0.025-0.04) mol:0.00025 mol:0.0001 mol.

[0010] Further, the 3-sulfonic acid group-2, 5-dibromothiophene, DMAC, and the molecular sieve are in a ratio of (3.21-32.1) g: 500 mL: 100 g; the molecular sieve is preferably 3A molecular sieve. Too low monomer concentration will reduce the probability of monomer collision, and the polymerization efficiency will decrease; too high monomer concentration will cause the viscosity of the system to increase rapidly, and the mixture will not be uniform, and crosslinked impurities will be generated; the pore size of the 3A molecular sieve is about 0.3 nm, and only water molecules can be adsorbed, and DMAC or monomers and catalysts cannot be adsorbed.

[0011] Further, in S1, the standing time is 3 h. Under this standing time, the coordination is the most sufficient.

[0012] Further, in S2, the reaction time is 72 h.

[0013] Further, in S2, the centrifugal speed is 6000-8000 rpm. The balance between complete separation and loose particles is achieved.

[0014] Further, in S2, the washing includes sequentially washing with dilute hydrochloric acid, deionized water, ethanol, tetrahydrofuran, and dilute sulfuric acid for 3 times respectively; the concentration of dilute hydrochloric acid is preferably 0.01 mol / L, and the concentration of dilute sulfuric acid is preferably 0.05-0.2 mol / L. Various solvents ensure the sufficient separation of inorganic impurities, organic impurities, and residual solvents.

[0015] Further, in S2, the vacuum drying temperature is 60-80℃.

[0016] Further, the density of the sulfuric acid is 1.4 g / cm 3 .

[0017] The second aspect is a preparation method of a positive electrode lead paste with high active material utilization rate, comprising the following steps: Lead powder, red lead, graphite, stannous sulfate, antimony trioxide, short fibers, and a sulfonic acid group polythiophene derivative additive are sequentially added to a paste machine, and after dry mixing, deionized water and sulfuric acid are added for wet mixing, and the obtained mixture is cooled while stirring to obtain a positive electrode lead paste with high active material utilization rate.

[0018] Further, the dry mixing time is 6-8 min, the addition time of water and sulfuric acid is 3-5 min, and the wet mixing time is 5-10 min; the stirring speed is 500-700 rpm, and the stirring time is 5-10 min.

[0019] Compared with the prior art, the present application has the following beneficial effects: 1. The invention provides a high active material utilization rate positive lead paste, comprising lead powder 100 parts, red lead 6-8 parts, graphite 0.1-0.2 parts, stannous sulfate 0.1-0.2 parts, antimony trioxide 0.05-1 parts, short fibers 0.2-0.8 parts, sulfonic acid-based polythiophene derivative additive 0.1-0.2 parts, sulfuric acid 5-15 parts, water 1-10 parts. The lead powder is the core prerequisite for the positive active material, and neutralization reaction occurs with sulfuric acid during the pasting process, providing a prerequisite for the subsequent battery formation stage to convert into positive active material lead dioxide; red lead is Pb3O4, which serves as an activity promoter to provide initial conductive sites for the positive electrode and ensure uniform distribution of PbO2; the layered structure of graphite forms a continuous conductive network in the lead paste, and antimony trioxide (Sb2O3) is a doped conductive modifier that can form a solid solution (Pb 2-x Sb x O2) with PbO2 during the formation stage, improving the electronic conductivity and structural stability of PbO2, and inhibiting the shedding and crystal transformation of PbO2 during the cycling process; the sulfonic acid-based polythiophene derivative is a key functional additive, and its mechanism has "electron-ion dual conduction" characteristics. The thiophene ring conjugated system in the molecular structure can provide an electron transport channel to supplement the weak areas of the graphite conductive network, and the sulfonic acid group (-SO3 - ) is a strong hydrophilic group that can form micro-ion channels inside the lead paste, promote the migration of H + , SO4 2 - in the electrolyte, and alleviate the ion concentration polarization on the surface of the active material during charging and discharging; its linear molecular chain can wrap around the surface of the active material particles to form a flexible "adhesion-conductive layer" that balances conductivity and structural stability. Stannous sulfate reduces the interface contact resistance, inhibits the corrosion of the current collector, and improves the cycle life of the battery; short fibers further mechanically entangle the active material particles, improving impact strength and flexibility and avoiding volume expansion during battery charging and discharging; water acts as a reaction medium and colloidal regulator, ensuring uniform dispersion of the components while providing the necessary pasting viscosity. The positive lead paste has good electrochemical oxidation-reduction performance, and when applied to lead-acid batteries, it can improve the conversion efficiency of the positive active material, effectively reduce the resistance of lead-acid batteries, improve the initial performance of lead-acid batteries, and prolong their cycle life, contributing to the development of lead-acid batteries.

[0020] 2. In the present application, graphite and antimony trioxide, sulfonic acid-based polythiophene derivatives form an "electron-ion dual conduction network", solving the dual bottleneck of electron transmission (PbO / PbSO4 insulation) and ion transmission (electrolyte migration blocked) in traditional lead paste, making the reaction sites on the surface of active material particles fully participate in the reaction (PbSO4-PbO2), effectively improving the utilization rate; short fibers and sulfonic acid-based polythiophene derivatives form a "flexible support-bonding system", which can buffer the volume expansion of active materials during charging and discharging (PbO2-PbSO4 volume increases, PbSO4-PbO2 volume decreases), avoiding lead paste cracking and active material shedding, and prolonging the cycle life of the battery.

[0021] 3. The positive electrode lead paste with high active material utilization rate provided by the present application has a simple paste process, and each process parameter is optimized, so that performance differences of the lead paste caused by operation fluctuations can be avoided, and the present application is suitable for industrial large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The equivalent circuit schematic diagram of the lead-acid battery made of the positive electrode lead paste prepared by the examples and comparative examples of the present application; Figure 2 The impedance comparison diagram of the lead-acid battery made of the positive electrode lead paste of example 4 and comparative example 1 of the present application; Figure 3 The cycle performance comparison diagram of the lead-acid battery made of the positive electrode lead paste of example 4 and comparative example 1 of the present application. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application are described in detail below, but it should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0025] It should be understood that in various embodiments of the present application, the size of the serial number of each process does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0026] The weight of the related components mentioned in the embodiment specification of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of each component. Therefore, as long as the content of the related components in the embodiment specification of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the embodiment specification of the present application. Specifically, the mass mentioned in the embodiment specification of the present application can be μg, mg, g, kg, etc. mass units commonly known in the chemical field.

[0027] Unless otherwise defined, all the professional terms used below have the same meaning as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0029] The following will be further illustrated with specific examples.

[0030] Example 1

[0031] The present embodiment provides a preparation method of a sulfonic acid group polythiophene derivative additive, comprising the following steps: S1. In a glove box under N2 conditions, 0.03 mol (9.57 g) of 2,5-dibromo-3- (methylsulfonyl) thiophene is added to a reaction bottle containing 500 mL of DMAC solvent, and the solution is stirred uniformly to obtain a monomer solution; 0.00025 mol (0.06876 g) of Ni (COD)2 and 0.0001 mol (0.0412 g) of DPPP are then added to the reaction bottle, followed by the addition of 100 g of 3A molecular sieves. The reaction bottle is left to stand at room temperature for 3 h, and then the 3A molecular sieves are separated to obtain a mixture, and a magnet is added to the reaction bottle, which is then sealed; S2. The reaction bottle containing the mixture is transferred from the glove box to a magnetic stirrer with a temperature setting of 80°C and a rotation speed of 1000 rpm, and stirred for 72 h. During the reaction, propanol is slowly added to the reaction bottle until the reactants are completely precipitated. A high-speed centrifuge is used to collect the reactants at a rotation speed of 7200 rpm, and 0.01 mol / L dilute hydrochloric acid, deionized water, ethanol, tetrahydrofuran and 0.1 mol / L dilute sulfuric acid are used to wash and centrifuge the reactants in sequence for 3 times. After washing, the product is transferred to a vacuum oven at 70°C for drying to obtain a sulfonic acid group polythiophene derivative additive.

[0032] Example 2

[0033] The embodiment provides a preparation method of the sulfonic acid group polythiophene derivative additive, and the difference from the embodiment 1 is that the 2,5-dibromo-3-(methylsulfonyl) thiophene is 0.025 mol (7.975 g), and the rest of the components and the preparation parameters remain unchanged.

[0034] Embodiment 3

[0035] The embodiment provides a preparation method of the sulfonic acid group polythiophene derivative additive, and the difference from the embodiment 1 is that the 2,5-dibromo-3-(methylsulfonyl) thiophene is 0.025 mol (7.975 g), and the rest of the components and the preparation parameters remain unchanged.

[0036] Embodiment 4

[0037] A high active material utilization rate positive lead paste, comprising the following components in parts by weight: Lead powder 100 parts, red lead 7 parts, graphite 0.15 parts, stannous sulfate 0.15 parts, antimony trioxide 0.08 parts, short fiber 0.5 parts, sulfonic acid group polythiophene derivative additive prepared in the embodiment 1 0.15 parts, sulfuric acid 10 parts, water 8 parts; The preparation method of the high active material utilization rate positive lead paste comprises the following steps: The lead powder, the red lead, the graphite, the stannous sulfate, the antimony trioxide, the short fiber and the sulfonic acid group polythiophene derivative additive are sequentially added into a paste machine, dry mixing is performed for 8 min, then the deionized water and the sulfuric acid are added within 4 min to perform wet mixing for 8 min, and the obtained mixture is cooled for 8 min at a stirring speed of 600 rpm, so that the high active material utilization rate positive lead paste is obtained.

[0038] Embodiment 5

[0039] A high active material utilization rate positive lead paste, and the difference from the embodiment 4 is that the sulfonic acid group polythiophene derivative additive is prepared from the embodiment 2, and the rest of the components and the preparation parameters remain unchanged.

[0040] Embodiment 6

[0041] A high active material utilization rate positive lead paste, and the difference from the embodiment 4 is that the sulfonic acid group polythiophene derivative additive is prepared from the embodiment 3, and the rest of the components and the preparation parameters remain unchanged.

[0042] Embodiment 7

[0043] A high active material utilization rate positive lead paste, and the difference from the embodiment 4 is that the weight fraction of the sulfonic acid group polythiophene derivative additive is 0.1 part, and the rest of the components and the preparation parameters remain unchanged.

[0044] Embodiment 8

[0045] A positive lead paste with high active material utilization rate, which is different from example 4 in that the weight fraction of the sulfonic acid group polythiophene derivative additive is 0.2 parts, and the rest of the components and preparation parameters remain the same as example 4.

[0046] Comparative example 1

[0047] A positive lead paste for lead-acid batteries, which is different from example 4 in that no sulfonic acid group polythiophene derivative additive prepared in example 1 is added, and the rest of the components and preparation parameters remain the same as example 4.

[0048] Comparative example 2

[0049] A positive lead paste for lead-acid batteries, which is different from example 4 in that the weight fraction of the sulfonic acid group polythiophene derivative additive is 0.3 parts, and the rest of the components and preparation parameters remain the same as example 4.

[0050] Performance test: The positive lead paste for lead-acid batteries prepared by examples 3-8 and comparative examples 1-2 was used to manufacture 12V lead-acid batteries, and the internal resistance of the batteries was tested, and the equivalent circuit is as shown in Figure 1 The impedance data obtained was fitted to obtain R1 (internal resistance) and R2 (charge transfer resistance) data of the lead-acid battery, and the data is summarized in Table 1, and the battery impedance comparison chart of example 4 and comparative example 1 is shown in Figure 2 . The obtained lead-acid battery was subjected to 100% DOD cycle test, and the initial battery capacity and the remaining capacity of the battery after 400 cycles were recorded, and the data is summarized in Table 1, and the battery cycle performance comparison chart of example 4 and comparative example 1 is shown in Figure 3 .

[0051] Table 1

[0052] The test results show that the lead-acid battery prepared by the high active positive electrode utilization rate positive lead paste of the present application has smaller R1 and R2 than the lead-acid battery without the sulfonic acid group polythiophene derivative additive (comparative example 1), which indicates that the lead-acid battery with the sulfonic acid group polythiophene derivative additive has smaller impedance and can exhibit more excellent performance; through the cycle performance test, it can be seen that the lead-acid battery with the sulfonic acid group polythiophene derivative additive has more excellent cycle performance and higher capacity, which indicates that by adding the sulfonic acid group polythiophene derivative additive, the conversion efficiency of the active material can be effectively improved, and the battery performance can be improved. In addition, if the amount of the sulfonic acid group polythiophene derivative additive is excessive, the impedance will increase, which indicates that the amount of the sulfonic acid group polythiophene derivative additive needs to be controlled within a certain range to maximize the advantage.

[0053] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the description herein. It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" or "the component" can include a plurality of such components unless the context clearly dictates otherwise.

[0054] The foregoing disclosure specifically encompasses all changes and modifications of the specific embodiments described herein falling within the scope of the invention.

Claims

1. A positive electrode lead paste with high utilization rate of active materials, characterized in that, Based on parts by weight, it includes the following components: 100 parts lead powder, 6-8 parts red lead, 0.1-0.2 parts graphite, 0.1-0.2 parts stannous sulfate, 0.05-1 parts antimony trioxide, 0.2-0.8 parts short fiber, 0.1-0.2 parts sulfonic acid polythiophene derivative additive, 5-15 parts sulfuric acid, and 1-10 parts water.

2. The positive electrode lead paste with high utilization rate of active material according to claim 1, characterized in that, The preparation method of the sulfonic acid-based polythiophene derivative additive includes the following steps: Under S1.N2 conditions, 2,5-dibromo-3-(methanesulfonyl)thiophene was added to N,N-dimethylacetamide, followed by Ni(COD)2 and 1,3-bis(diphenylphosphine propane), and then molecular sieves were added. After standing at room temperature for 1-4 hours, the molecular sieves were separated to obtain a mixture. S2. The mixture is placed at 60-100℃ and 600-1200rpm for 24-86h. Propanol is added during the reaction to precipitate the reactants. After the reaction is completed, the mixture is centrifuged, washed and vacuum dried to obtain the sulfonic acid polythiophene derivative additive.

3. The positive electrode lead paste with high utilization rate of active material according to claim 2, characterized in that, In S1, the molar ratio of 3-sulfono-2,5-dibromothiophene, Ni(COD)2, and 1,3-bis(diphenylphosphine propane) is (0.01-0.1) mol: (0.0001-0.001) mol: (0.00005-0.0005) mol.

4. The positive electrode lead paste with high utilization rate of active material according to claim 2, characterized in that, The ratio of 3-sulfonic acid-2,5-dibromothiophene, N,N-dimethylacetamide, and molecular sieve is (3.21-32.1) g: 500 mL: 100 g.

5. The positive electrode lead paste with high utilization rate of active material according to claim 2, characterized in that, In S1, the settling time is 3 hours.

6. The positive electrode lead paste with high utilization rate of active material according to claim 2, characterized in that, In S2, the centrifugal speed is 6000-8000 rpm.

7. The positive electrode lead paste with high utilization rate of active material according to claim 2, characterized in that, In S2, the washing process includes washing three times each with 0.01 mol / L dilute hydrochloric acid, deionized water, ethanol, tetrahydrofuran, and 0.05-0.2 mol / L dilute sulfuric acid.

8. The positive electrode lead paste with high utilization rate of active material according to claim 1, characterized in that, The sulfuric acid has a density of 1.4 g / cm³. 3 .

9. A method for preparing a positive electrode lead paste with high utilization rate of active materials, used to prepare the positive electrode lead paste with high utilization rate of active materials as described in any one of claims 1-8, characterized in that, Includes the following steps: Lead powder, red lead, graphite, stannous sulfate, antimony trioxide, short fibers, and sulfonic acid-based polythiophene derivative additives are added sequentially to the paste mixing machine. After dry mixing, deionized water and sulfuric acid are added for wet mixing. The resulting mixture is stirred and cooled simultaneously to obtain a positive electrode lead paste with high utilization rate of active materials.

10. The method for preparing the positive electrode lead paste with high utilization rate of active materials according to claim 9, characterized in that, The dry mixing time is 6-8 minutes, the water and sulfuric acid addition time is 3-5 minutes, and the wet mixing time is 5-10 minutes; the stirring speed is 500-700 rpm, and the stirring time is 5-10 minutes.

Images