Lead-acid battery plate, method of making and use thereof

Abstract

The application relates to the technical field of storage batteries, and particularly discloses a lead-acid battery plate and a preparation method and application thereof. The application forms a nano-porous structure on the surface of a grid and introduces a hydroxyl functional group through alloying and selective corrosion oxidation treatment of the surface of the grid, and meanwhile, a composite active substance of carboxylated g-C3N4 and a lead-based substance is prepared by plasma high-energy ball milling. Then, high-strength chemical combination of the grid and the active substance interface is realized through the synergistic effect of covalent bonding between the hydroxyl generated in situ on the surface of the grid and the carboxylated g-C3N4 in the active substance and coordination bonding between N atoms and lead ions; meanwhile, a three-dimensional continuous electron conduction path is constructed in the active substance with the aid of uniformly dispersed carboxylated g-C3N4, a high-efficiency bulk phase conductive network is formed, and the cycle life, rate performance and active substance utilization rate of the battery are significantly improved, so that the application has a wide application prospect in the fields of energy storage systems, automobile start-stop power supplies and the like.

Description

Technical Field

[0001] This invention relates to the field of storage battery technology, and in particular to a lead-acid battery electrode plate, its preparation method, and its application. Background Technology

[0002] Lead-acid batteries are widely used in energy storage systems, electric vehicles, and backup power supplies for communication base stations due to their significant advantages such as low cost, high safety, stable charge and discharge performance, and high recyclability. The grid, as the core component of the battery, is not only the mechanical framework supporting the active materials but also a key channel for achieving uniform current collection and efficient conduction within the battery. Its structure and performance directly affect the battery's capacity, cycle life, and charge and discharge efficiency.

[0003] However, traditional lead-acid batteries suffer from several key problems: First, the bonding strength between the grid and the active material is insufficient. Especially during cyclic charging and discharging, the positive electrode active material (mainly PbO2) is prone to interfacial loosening or even detachment from the grid, leading to decreased utilization of the active material, battery capacity decay, and increased internal resistance, becoming one of the main causes of early battery failure. Second, the charge conductivity within the active material is poor: the conductivity within the active material depends on lead oxide, which has limited conductivity, especially during high-rate discharge, easily causing polarization and affecting battery power. Furthermore, the aforementioned weak interfacial bonding and insufficient conductivity together prevent the active material from fully participating in electrochemical reactions, resulting in low specific capacity and specific energy, thus limiting the application of lead-acid batteries in high-efficiency energy storage scenarios.

[0004] To improve conductivity, existing technologies have attempted to add carbon materials to the electrodes. However, carbon materials exhibit poor chemical stability in the highly acidic, high-potential internal environment of batteries, and their interfacial compatibility and bonding with lead-based active materials are weak, making them prone to degradation or delamination during cycling, thus hindering the continuous and stable improvement of battery performance. Therefore, how to enhance the bonding between the grid and the active material while constructing a stable and efficient conductive network and improving the utilization efficiency of the active material has become a key issue that urgently needs to be addressed in the current lead-acid battery technology field. Summary of the Invention

[0005] To address the problems of weak interfacial bonding between the grid and active material, poor charge conduction of the active material, and low utilization rate in traditional lead-acid battery grids, this invention provides a lead-acid battery electrode plate, its preparation method, and its application.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a lead-acid battery electrode plate, comprising the following steps:

[0008] S1. After preheating the grid substrate, immerse it in a lead-tin eutectic alloy molten pool, remove the plated grid substrate, then use a high-speed airflow to blow its surface, and then cool it at a rate of 5℃ / s~10℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, thus obtaining an alloy-plated grid.

[0009] S2, the alloy-plated grid is immersed in an acidic solution containing an oxidant for surface oxidation treatment to obtain a pretreated grid;

[0010] S3, mix lead-based active material and g-C3N4 to obtain a mixture; subject the mixture to plasma high-energy ball milling at 300W~1000W under micro-oxygen conditions to obtain a composite active material; wherein, the mass percentage of g-C3N4 in the mixture is not less than 0.5%;

[0011] S4. The composite active material is made into lead paste, which is then coated onto the pretreated grid and cured to obtain a lead-acid battery electrode plate.

[0012] Compared to existing technologies, the method for preparing lead-acid battery plates provided by this invention first involves immersing a lead-tin eutectic alloy onto the surface of the grid substrate, and then controlling the cooling rate to obtain a lead-rich α phase and a tin-rich β phase, laying the foundation for subsequent selective corrosion. The lead-rich α phase is preferentially corroded due to its higher oxidative dissolution thermodynamic driving force, while the chemically more stable tin-rich β phase is completely preserved, ultimately forming a sponge-like structure with nanoscale pores on the grid surface. This structure not only significantly increases the specific surface area and roughness of the grid, providing abundant physical anchoring sites for the active material, but also allows the newly formed lead oxide surface from the oxidation reaction to in situ form abundant hydroxyl (-OH) functional groups, endowing the interface with high chemical reactivity.

[0013] When lead oxide and g-C3N4 are subjected to plasma high-energy ball milling at a specific power, O2 in the air is ionized into active substances (such as oxygen free radicals). O (such as O, ozone O3), these highly reactive oxygen species attack the defects and dangling bonds in g-C3N4 caused by mechanical force and plasma bombardment, thereby grafting oxygen-containing functional groups such as carboxyl groups onto its skeleton edges and surface, resulting in carboxylated g-C3N4.

[0014] Carboxylated g-C3N4 forms a strong chemical bond with the hydroxyl groups on the grid surface, significantly improving the interfacial bonding strength between the grid and the active material compared to traditional structures. This prevents the active material from stripping away during cycling, suppressing capacity decay and internal resistance growth. Furthermore, g-C3N4 itself possesses excellent conductivity, allowing for the construction of continuous conductive pathways within the active material. Additionally, the nitrogen atom in g-C3N4 can interact with Pb via lone pair electrons. 2+Stable coordination bonds are formed. The Pb-N coordination bonds can anchor the g-C3N4 network to the surrounding lead oxide particles, greatly enhancing the interfacial bonding force and the dispersibility of g-C3N4 in lead-based active materials, ensuring the continuity of the conductive pathway and the stability of the interfacial bonding.

[0015] In summary, the lead-acid battery electrode preparation method provided by this invention significantly suppresses capacity decay and internal resistance growth during battery cycling through the dual interfacial effects of covalent bonding and coordination anchoring, as well as the synergistic effect of continuous conductive pathways. This, in turn, helps to significantly improve the cycle life and electrochemical performance stability of lead-acid batteries, providing a new approach for developing long-life, high-power lead-acid batteries. It also has broad application prospects in energy storage systems, automotive start-stop power supplies, and backup power.

[0016] Specifically, in S1, the grid substrate is a lead-calcium grid.

[0017] Specifically, in S1, the lead-tin eutectic alloy is 38.1% Pb-61.9% Sn.

[0018] In one specific embodiment of the present invention, the grid substrate is vertically immersed into a lead-tin eutectic alloy molten pool. The speed at which the grid substrate enters the lead-tin eutectic alloy molten pool is 1 m / min to 10 m / min, and the speed at which it is pulled out of the lead-tin eutectic alloy molten pool is also controlled to be 1 m / min to 10 m / min.

[0019] Furthermore, in S1, the thickness of the lead-tin eutectic alloy layer is 5μm~30μm.

[0020] In one specific embodiment of the present invention, the coating thickness can be precisely limited to 5μm~30μm by blowing a high-speed airflow through an air knife system. For example, the distance between the air knife and the surface of the grid substrate is controlled to be 10mm~50mm, the angle of the air knife relative to the perpendicular direction of the grid substrate is 0°~15°, and the width of the air knife slit is 0.5mm~2.0mm.

[0021] Furthermore, in S1, the preheating temperature is 160℃~220℃.

[0022] Preheating the grid substrate to 160℃~220℃ can effectively reduce the thermal stress during immersion in the molten pool and avoid adverse effects on the grid structure.

[0023] Specifically, in S1, the temperature of the lead-tin eutectic alloy molten pool is 200℃~250℃ to fully ensure the fluidity of the alloy.

[0024] Further, in S2, the acidic solution containing the oxidant is an acidic solution of hydrogen peroxide with a pH value of 1.0 to 4.0 and a mass concentration of 10% to 30% for the hydrogen peroxide.

[0025] Specifically, the pH of the hydrogen peroxide solution is adjusted to 1.0~4.0 using dilute sulfuric acid solution.

[0026] Furthermore, in S2, the surface oxidation treatment is carried out at a temperature of 30°C to 50°C for a time of 20 min to 40 min.

[0027] The optimized oxidation treatment conditions can effectively promote the selective oxidation and dissolution of the lead-rich α phase, and work synergistically with the acidic environment to ensure the formation of a uniform, high specific surface area nanoporous structure on the β phase framework, avoiding excessive corrosion or damage to the alloy layer structure.

[0028] Specifically, in S3, the lead-based active material includes lead powder (Pb), lead oxide (PbO), and red lead (Pb3O4).

[0029] Furthermore, in S3, the mass percentage of g-C3N4 in the mixture is 0.5% to 5%.

[0030] The optimal amount of g-C3N4 added ensures the construction of a continuous and efficient conductive network in the active material.

[0031] Furthermore, in S3, the rotation speed of the plasma high-energy ball mill is 300 rpm to 600 rpm, and the ball milling time is 2 h to 10 h; a periodic intermittent discharge mode is adopted during the ball milling process, wherein the discharge interval is 5 min to 15 min, and the duration of each discharge is 1 min to 5 min.

[0032] The optimized conditions for plasma high-energy ball milling can avoid excessive damage to the g-C3N4 skeleton or loss of graphitization structure, and while introducing functional groups such as carboxyl groups, it can preserve the integrity of the conductive network of g-C3N4 itself to the greatest extent.

[0033] Furthermore, the ball-to-material ratio in S3 is 10:1 to 30:1.

[0034] It should be noted that in S3, the micro-oxygen conditions of the plasma high-energy ball mill are achieved by introducing argon gas containing trace amounts of oxygen, wherein the volume concentration of oxygen is 0.1% to 1%. In this mixed gas, argon acts as the host gas, maintaining stable plasma discharge and preventing excessive oxidation, while the trace oxygen provides the necessary active oxygen species for the carboxylation reaction on the g-C3N4 surface. This oxygen concentration range ensures the generation of sufficient active oxygen radicals for efficient grafting of oxygen-containing functional groups, while avoiding excessive oxygen content that could lead to excessive oxidation and damage to the g-C3N4 framework or unnecessary deep oxidation of the lead component. Thus, effective functionalization of the material is achieved while maintaining its structural stability and electrochemical activity.

[0035] Further, S4 specifically includes: mixing the composite active material, short fiber, barium sulfate, sodium lignosulfonate and water evenly, and adding dilute sulfuric acid to obtain lead paste.

[0036] Specifically, the amount of short fiber added is 0.1% of the mass of the composite active substance, the amount of barium sulfate added is 0.5% of the mass of the composite active substance, and the amount of sodium lignosulfonate added is 0.2% of the mass of the composite active substance.

[0037] Further, in S4, the specific steps of curing include: treating the coated electrode plate at a temperature of 75±5℃ and a relative humidity of >98% for 18 hours, and then treating it at a temperature of 55±5℃ and a relative humidity gradually decreasing to below 20% for 28 hours.

[0038] Secondly, the present invention provides a lead-acid battery electrode plate, which is prepared by the method for preparing lead-acid battery electrode plates described in any of the above claims.

[0039] Thirdly, the present invention also provides a lead-acid battery, including the aforementioned lead-acid battery plates.

[0040] In summary, the method for preparing lead-acid battery plates provided by this invention involves alloying the grid surface and selectively corroding and oxidizing it to form a nanoporous structure and introduce hydroxyl functional groups. Simultaneously, a composite active material of carboxylated g-C3N4 and lead-based materials is prepared using plasma high-energy ball milling. Then, through the covalent bonding between the hydroxyl groups generated in situ on the grid surface and the carboxylated g-C3N4 in the active material, as well as the synergistic effect of the coordination bonds between N atoms and lead ions, a high-strength chemical bond is achieved at the interface between the grid and the active material. Furthermore, the uniformly dispersed carboxylated g-C3N4 constructs a three-dimensional continuous electronic conduction pathway within the active material, forming a highly efficient bulk conductive network. This significantly improves the battery's cycle life, rate performance, and active material utilization rate, showing broad application prospects in energy storage systems, automotive start-stop power supplies, and backup power. Attached Figure Description

[0041] Figure 1 The images are SEM images of the alloy-coated grid and the pre-treated grid in Embodiment 1 of the present invention, wherein (a) is the alloy-coated grid and (b) is the pre-treated grid.

[0042] Figure 2 The infrared spectra of the alloy-coated grid and the pre-treated grid in Embodiment 1 of the present invention are shown.

[0043] Figure 3 The images show the infrared spectra of the original g-C3N4 and the g-C3N4 after plasma high-energy ball milling in Example 1 of this invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] To better illustrate the present invention, further examples are provided below.

[0046] The grid substrate used in the following examples is a lead-calcium grid; the lead-tin eutectic alloy is 38.1% Pb-61.9% Sn.

[0047] Example 1

[0048] This invention provides a method for preparing lead-acid battery plates, specifically including the following steps:

[0049] S1. The clean grid substrate is continuously passed through an acid pickling and flux bath to remove the surface oxide film. Then, it is preheated to 200°C. The preheated grid substrate is vertically immersed in a lead-tin eutectic alloy molten pool at a speed of 5 m / min. The molten pool temperature is 220°C. After complete immersion, it is vertically pulled out of the molten pool at a speed of 5 m / min. A high-speed nitrogen gas flow is sprayed from an air knife to clean the surface of the grid substrate after immersion. The distance between the air knife and the surface of the grid substrate is controlled at 30 mm, the angle of the air knife to the perpendicular direction of the grid substrate is 0°, and the width of the air knife slit is 1.0 mm.

[0050] S2, after purging, cool at a rate of 8℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, and obtain an alloy-plated grid.

[0051] S3. Immerse the above alloy-coated grid in an acidic solution containing 20wt% hydrogen peroxide (adjust pH to 2.2 with dilute sulfuric acid) in a constant temperature water bath at 40°C for 30 minutes. Remove the grid, rinse it with deionized water, and dry it in a vacuum drying oven at 80°C for 2 hours to obtain the pretreated grid.

[0052] S4. 99.0 wt% PbO and 1.0 wt% g-C3N4 powder were mixed and placed in a plasma high-energy ball mill. Argon gas with an oxygen concentration of 0.2% was introduced. The discharge power was set to 500 W, the ball-to-material ratio to be 25:1, the rotation speed to be 400 rpm, and the ball milling time to be 4 h. During the ball milling process, a periodic intermittent discharge mode was adopted, with a discharge interval of 10 min and each discharge lasting for 3 min, to obtain a composite active material.

[0053] S5, the above-mentioned composite active material, 70% deionized water, 0.1 wt% short fiber of the composite active material, 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3 Lead paste was applied to the pretreated grid, and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%, and then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0054] The SEM images of the alloy-coated grid and the pretreated grid in embodiment S3 are as follows: Figure 1 As shown in the figure, Figure 1 (a) It can be seen that the surface of the grid that has not been corroded by H2O2 is smooth and flat, while from... Figure 1 In (b), it is evident that the grid exhibits significant pores after H2O2 corrosion. The formation of these pores is primarily due to the preferential corrosion removal of the lead-rich α phase, while the more chemically stable tin-rich β phase remains intact and forms a porous framework. This porous structure not only significantly increases the specific surface area of ​​the grid, providing ample physical anchoring points for subsequent lead paste coating, but also allows the fresh oxide layer exposed on the grid surface to fully contact the reaction system.

[0055] Figure 2 Infrared spectra of alloy-coated grids and pretreated grids. Figure 3 Infrared spectra of pristine g-C3N4 and g-C3N4 after plasma high-energy ball milling. From... Figure 2 As can be seen, in the infrared spectrum of the alloy-coated grating without H2O2 corrosion, the characteristic absorption peak of hydroxyl (-OH) (approximately 3200~3600 cm⁻¹) is present. -1 In the first interval, there was almost no obvious signal; however, in the second interval, the pretreated grid after H2O2 acid etching showed a high intensity hydroxyl characteristic peak, confirming that the H2O2 etching process can directionally construct abundant hydroxyl functional groups on the grid surface, providing active sites for subsequent chemical bonding with active substances.

[0056] Depend on Figure 3 It can be seen that in the infrared spectrum of the original g-C3N4 without plasma high-energy ball milling, the characteristic absorption peak of the carboxyl group (-COOH) (approximately 1700~1750 cm⁻¹) is present. -1The region was missing; after plasma high-energy ball milling, a clear characteristic absorption peak of carboxyl groups appeared in this region, indicating that carboxyl functional groups were successfully grafted onto the g-C3N4 surface under plasma high-energy ball milling. The directional construction of the above-mentioned hydroxyl and carboxyl groups provides a key chemical basis for the formation of strong chemical bonds between the grid and the composite active material.

[0057] Example 2

[0058] This invention provides a method for preparing lead-acid battery plates, specifically including the following steps:

[0059] S1. The clean grid substrate is continuously passed through an acid pickling and flux bath to remove the surface oxide film. Then, it is preheated to 220°C. The preheated grid substrate is vertically immersed in a lead-tin eutectic alloy molten pool at a speed of 4 m / min. The molten pool temperature is 250°C. After complete immersion, it is vertically pulled out of the molten pool at a speed of 4 m / min. A high-speed nitrogen gas flow is sprayed from an air knife to clean the surface of the immersed grid substrate. The distance between the air knife and the surface of the grid substrate is controlled at 20 mm, the angle of the air knife to the perpendicular direction of the grid substrate is 10°, and the width of the air knife slit is 1.5 mm.

[0060] S2, after purging, cool at a rate of 7℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, and obtain an alloy-plated grid.

[0061] S3, Immerse the above alloy-coated grid in an acidic solution containing 25wt% hydrogen peroxide (adjust pH to 3.0 with dilute sulfuric acid), bathe in a constant temperature water bath at 35°C for 35 minutes, remove the grid, rinse with deionized water, and dry in a vacuum drying oven at 80°C for 2 hours to obtain the pretreated grid.

[0062] S4. 98.0 wt% PbO and 2.0 wt% g-C3N4 powder were mixed and placed in a plasma high-energy ball mill. Argon gas with an oxygen concentration of 0.3% was introduced. The discharge power was set to 700 W, the ball-to-material ratio to be 30:1, the rotation speed to be 500 rpm, and the ball milling time to be 5 h. During the ball milling process, a periodic intermittent discharge mode was adopted, with a discharge interval of 8 min and each discharge lasting for 2 min, to obtain a composite active material.

[0063] S5, the above-mentioned composite active material, 70% deionized water, 0.1 wt% short fiber of the composite active material, 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3Lead paste was applied to the pretreated grid, and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%, and then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0064] Example 3

[0065] This invention provides a method for preparing lead-acid battery plates, specifically including the following steps:

[0066] S1. The clean grid substrate is continuously passed through an acid pickling and flux bath to remove the surface oxide film. Then, it is preheated to 160°C. The preheated grid substrate is vertically immersed in a lead-tin eutectic alloy molten pool at a speed of 1 m / min. The molten pool temperature is 200°C. After complete immersion, it is vertically pulled out of the molten pool at a speed of 1 m / min. A high-speed nitrogen gas flow is sprayed from an air knife to clean the surface of the grid substrate after immersion. The distance between the air knife and the surface of the grid substrate is controlled at 10 mm, the angle of the air knife to the perpendicular direction of the grid substrate is 5°, and the width of the air knife slit is 2.0 mm.

[0067] S2, after purging, cool at a rate of 5℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, and obtain an alloy-plated grid.

[0068] S3. Immerse the above alloy-coated grid in an acidic solution containing 30wt% hydrogen peroxide (adjust pH to 3.9 with dilute sulfuric acid), bathe in a constant temperature water bath at 50°C for 20 minutes, remove the grid, rinse with deionized water, and dry in a vacuum drying oven at 80°C for 2 hours to obtain the pretreated grid.

[0069] S4. 95.0 wt% PbO and 5.0 wt% g-C3N4 powder were mixed and placed in a plasma high-energy ball mill. Argon gas with an oxygen concentration of 0.1% was introduced. The discharge power was set to 300 W, the ball-to-material ratio to be 20:1, the rotation speed to be 300 rpm, and the ball milling time to be 10 h. During the ball milling process, a periodic intermittent discharge mode was adopted, with a discharge interval of 5 min and each discharge lasting for 1 min, to obtain a composite active material.

[0070] S5, the above-mentioned composite active material, 70% deionized water, 0.1 wt% short fiber of the composite active material, 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3Lead paste was applied to the pretreated grid, and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%, and then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0071] Example 4

[0072] This invention provides a method for preparing lead-acid battery plates, specifically including the following steps:

[0073] S1. The clean grid substrate is continuously passed through an acid pickling and flux bath to remove the surface oxide film. Then, it is preheated to 180°C. The preheated grid substrate is vertically immersed in a lead-tin eutectic alloy molten pool at a speed of 10 m / min. The molten pool temperature is 220°C. After complete immersion, it is vertically pulled out of the molten pool at a speed of 10 m / min. A high-speed nitrogen gas flow is sprayed from an air knife to clean the surface of the immersion-plated grid substrate. The distance between the air knife and the surface of the grid substrate is controlled at 50 mm, the angle of the air knife to the perpendicular direction of the grid substrate is 15°, and the width of the air knife slit is 0.5 mm.

[0074] S2, after purging, cool at a rate of 10℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, and obtain an alloy-plated grid.

[0075] S3, Immerse the above alloy-coated grid in an acidic solution containing 10wt% hydrogen peroxide (adjust pH to 1.2 with dilute sulfuric acid), bathe in a constant temperature water bath at 30°C for 40 minutes, remove the grid, rinse with deionized water, and dry in a vacuum drying oven at 80°C for 2 hours to obtain the pretreated grid.

[0076] S4. 99.5 wt% PbO and 0.5 wt% g-C3N4 powder were mixed and placed in a plasma high-energy ball mill. Argon gas with an oxygen concentration of 1% was introduced. The discharge power was set to 1000 W, the ball-to-material ratio was 10:1, the rotation speed was 600 rpm, and the ball milling time was 2 h. During the ball milling process, a periodic intermittent discharge mode was adopted, with a discharge interval of 15 min and each discharge lasting for 5 min, to obtain a composite active material.

[0077] S5, the above-mentioned composite active material, 70% deionized water, 0.1 wt% short fiber of the composite active material, 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3Lead paste was applied to the pretreated grid, and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%, and then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing lead-acid battery plates. The only difference from Example 1 is that the cooling rate in S2 is 100°C / s. The rest is exactly the same and will not be described again here.

[0080] Comparative Example 2

[0081] This comparative example provides a method for preparing lead-acid battery plates. The only difference from Example 1 is that in S4, lead oxide is 99.9 wt% and g-C3N4 powder is 0.1 wt%. The rest are exactly the same and will not be described again here.

[0082] Comparative Example 3

[0083] This comparative example provides a method for preparing lead-acid battery plates. The only difference from Example 1 is that the discharge power of the plasma high-energy ball milling in S4 is 1500W. The rest are exactly the same and will not be described again here.

[0084] Comparative Example 4

[0085] This comparative example provides a method for preparing lead-acid battery plates, which differs from Example 1 only in that the original grid substrate is coated with a composite active material. The specific steps are as follows:

[0086] S1, 99.0 wt% PbO and 1.0 wt% g-C3N4 powder were mixed and placed in a plasma high-energy ball mill. Argon gas with an oxygen concentration of 0.2% was introduced. The discharge power was set to 500 W, the ball-to-material ratio was 25:1, the rotation speed was 400 rpm, and the ball milling time was 4 h. During the ball milling process, a periodic intermittent discharge mode was adopted, with a discharge interval of 10 min and each discharge lasting for 3 min, to obtain a composite active material.

[0087] S2, the above-mentioned composite active material, 70% deionized water, 0.1 wt% short fiber of the composite active material, 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3Lead paste was applied to an untreated grid substrate and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%. The substrate was then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0088] Comparative Example 5

[0089] This comparative example provides a method for preparing lead-acid battery plates, which differs from Example 1 only in that g-C3N4 is not added, and plasma high-energy ball milling is performed. The specific steps are as follows:

[0090] S1~S3 are the same as in Example 1, and will not be described again here;

[0091] S4, PbO powder, 70% deionized water, 0.1 wt% short fibers (by weight of PbO powder), 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3 Lead paste was applied to the pretreated grid, and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%, and then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0092] Comparative Example 6

[0093] This comparative example provides a method for preparing lead-acid battery plates. The only difference from Example 1 is that pure PbO powder is used as the active material, g-C3N4 is not added, and the grid substrate is not pretreated. The specific steps are as follows:

[0094] PbO powder, 70% deionized water, 0.1 wt% short fibers (by weight of PbO powder), 0.5 wt% barium sulfate, and 0.2 wt% sodium lignosulfonate are mixed in a paste mixer, and then slowly added with a density of 1.40 g / cm³. 3 Dilute sulfuric acid (calculated as pure H2SO4, accounting for 10wt% of the total amount of composite active material) is added, followed by the remaining deionized water, to prepare a solution of 4.2 g / cm³. 3 Lead paste was applied to an untreated grid substrate and then treated for 18 hours at a temperature of 75±5℃ and relative humidity >98%. The substrate was then treated for 28 hours at a temperature of 55±5℃ and relative humidity gradually decreasing to below 20% to obtain lead-acid battery plates.

[0095] Performance testing

[0096] The plates prepared in Examples 1-4 and Comparative Examples 1-6 were used to assemble lead-acid batteries and perform performance tests according to the following method.

[0097] Step 1, Formation: Place the cured electrode plate in a formation tank and inject an amount of material with a density of 1.10 g / cm³. 3 A dilute sulfuric acid electrolyte was used, with the electrode plates submerged. A constant current charging method was employed, with a current density of 10 mA / cm². 2 The total charging capacity is 1.5 times the theoretical capacity. During charging, the electrolyte temperature is controlled to not exceed 50℃. After charging is complete, the plates are removed, rinsed with deionized water to remove surface acid, and then dried to obtain the positive plate.

[0098] Step 2, Separator Treatment: Cut the glass fiber (AGM) separator to the size that matches the electrode plate, and soak it in deionized water for more than 30 minutes to fully wet it, so as to facilitate subsequent electrolyte filling.

[0099] Step 3, Electrode Assembly: On a clean workbench, stack the electrodes in the following order: negative electrode plate, wetted separator, positive electrode plate, wetted separator, negative electrode plate, with the tabs facing the same side. Then, assemble the stacked electrode assembly into a transparent plexiglass (acrylic) test battery case.

[0100] Step 4, Welding and Encapsulation: Weld the tabs of the same polarity together to form a busbar. Terminal Lead-out: Weld the positive and negative busbars to the lead-out terminals respectively. Battery Case Sealing: Fill the sealing groove of the battery case cover with silicone rubber sealant. Replace the cover and tighten the fixing screws evenly to ensure the battery case is completely sealed, preventing leakage and oxygen ingress.

[0101] Step 5, Liquid Injection: Place the battery in a vacuum liquid injection machine, evacuate to -0.06MPa ~ -0.08MPa, and maintain this pressure for 5~10 minutes to remove air from the electrode groups and separators. While maintaining the vacuum, draw in a sufficient amount of 1.280±0.005 g / cm³ of liquid injection solution through the injection tube. 3 (25℃) Sulfuric acid electrolyte, until the liquid level is 10~15mm above the top of the electrode group.

[0102] The assembled battery was subjected to charge-discharge tests under constant current, and the mass energy density was calculated based on the first discharge curve and the battery mass.

[0103] Charge the battery using a 0.2C current. When the voltage rises to 2.45V, switch to constant voltage charging. Charging is considered complete when the current drops to 0.05C or the total charging time reaches 3 hours. After charging, discharge the battery for 20 minutes at a 1C current. Discharge stops when the battery voltage drops to 1.75V. This constitutes one cycle. Repeat this charge-discharge process 200 times. Record the ratio of the discharge capacity at the 200th cycle to the initial discharge capacity; this is the capacity retention rate.

[0104] The adhesion force between the active material and the grid was tested using a pull-out test method. The specific steps are as follows:

[0105] Sample preparation: After curing and drying, the electrode plate is cut into samples of specified size using a precision cutting machine. The effective test area is 20mm × 20mm.

[0106] Adhesion and Fixing: Using a high-strength, heat-resistant two-component epoxy resin adhesive, the side of the grid without active materials is vertically bonded to a special steel clamp, while the other side containing active materials is bonded to a corresponding clamp. Ensure a firm bond and accurate alignment.

[0107] Pull-out test: The assembled fixture is installed on a universal testing machine, and a tensile force perpendicular to the grid surface is applied at a constant rate of 1 mm / min until the active material layer is detached or the interface separates.

[0108] Data recording: Record the tension-displacement curve and take the maximum force value (in Newtons, N) at the moment the active material falls off.

[0109] Adhesive strength is calculated using the following formula:

[0110] σ=F max / A,

[0111] In the formula, σ: bonding strength, MPa; F max A: Maximum tensile force, N; A: Effective test area, mm 2 .

[0112] The test results are shown in Table 1.

[0113] Table 1

[0114]

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a lead-acid battery electrode plate, characterized in that, Includes the following steps: S1. After preheating the grid substrate, immerse it in a lead-tin eutectic alloy molten pool, remove the plated grid substrate, then use a high-speed airflow to blow its surface, and then cool it at a rate of 5℃ / s~10℃ / s to form a lead-tin eutectic alloy layer on the surface of the grid substrate, thus obtaining an alloy-plated grid. S2, the alloy-plated grid is immersed in an acidic solution containing an oxidant for surface oxidation treatment to obtain a pretreated grid; S3, mix lead-based active material and g-C3N4 to obtain a mixture; subject the mixture to plasma high-energy ball milling at 300W~1000W under micro-oxygen conditions to obtain a composite active material; wherein, the mass percentage content of g-C3N4 in the mixture is not less than 0.5%; and the volume concentration of oxygen under micro-oxygen conditions is 0.1%~1%; S4. The composite active material is made into lead paste, which is then coated onto the pretreated grid and cured to obtain a lead-acid battery electrode plate.

2. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S1, the thickness of the lead-tin eutectic alloy layer is 5μm~30μm.

3. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S1, the preheating temperature is 160℃~220℃.

4. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S2, the acidic solution containing the oxidant is an acidic solution of hydrogen peroxide with a pH value of 1.0 to 4.0 and a mass concentration of 10% to 30% for the hydrogen peroxide.

5. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S2, the surface oxidation treatment is carried out at a temperature of 30℃~50℃ for a time of 20min~40min.

6. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S3, the mass percentage of g-C3N4 in the mixture is 0.5% to 5%.

7. The method for preparing lead-acid battery plates as described in claim 1, characterized in that, In S3, the rotation speed of the plasma high-energy ball mill is 300 rpm to 600 rpm, and the ball milling time is 2 h to 10 h. During the ball milling process, a periodic intermittent discharge mode is adopted, wherein the discharge interval is 5 min to 15 min, and the duration of each discharge is 1 min to 5 min.

8. A lead-acid battery electrode plate, characterized in that, It is prepared by the method for preparing lead-acid battery plates according to any one of claims 1 to 7.

9. A lead-acid battery, characterized in that, Includes the lead-acid battery plate as described in claim 8.

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