Corrosion-resistant lead-based storage battery plate and method of making same
By treating the modified cobalt phosphate suspension and using staged drying and cooling technology, a dense protective film is formed, which solves the problem of cobalt phosphate agglomeration, improves the corrosion resistance and electrochemical performance of lead-based battery plates, and extends battery life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG TIANNENG POWER ENERGY
- Filing Date
- 2026-06-24
- Publication Date
- 2026-07-31
AI Technical Summary
In existing technologies, cobalt phosphate is prone to agglomeration, which makes it difficult to fully utilize its corrosion resistance and limits the effectiveness of lead-acid battery plates.
By preparing a modified cobalt phosphate suspension, the positive electrode grid is immersed in the modified cobalt phosphate suspension and heated to a warm temperature to form a dense cobalt phosphate pre-coating layer. Combined with a staged temperature and humidity drying and cooling treatment, a dense protective film is formed. Positive electrode lead paste is prepared through a paste-making process to ensure that the lead paste is tightly bonded to the grid.
It significantly improves the corrosion resistance and electrochemical performance of lead-based battery plates, reduces the risk of softening and shedding of active materials, optimizes electron transport efficiency, and improves battery cycle performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of lead-acid battery technology, and in particular to a corrosion-resistant lead-based battery electrode plate and its preparation method. Background Technology
[0002] As a power source that can repeatedly store and discharge electricity, the storage battery has replaced the traditional dry cell battery and is widely used in daily life due to its convenience and ability to be repeatedly charged and discharged. The plates are an important component of the lead-based storage battery, which play a role in supporting the active material, acting as a carrier of the active material, conducting current, and making the current evenly distributed on the active material.
[0003] Lead-based battery plates possess inherent corrosion resistance, oxidation resistance, and reduction resistance. However, during the long-term service life of lead-acid batteries, the positive grid is constantly under a high-potential environment. Regardless of whether it is charging or discharging, the grid will continuously undergo oxidation and form a corrosion layer. When the grid is severely corroded, unable to provide effective support for the active materials, or when its charge transport capacity is significantly reduced, failing to achieve efficient charge introduction and removal, the cycle life of the lead-acid battery will end.
[0004] Patent CN112786898B discloses a method for preparing a positive electrode plate and a lead-acid battery. This technical solution involves immersing a continuously cast positive electrode grid in a cobalt phosphate suspension. After a settling process, cobalt phosphate particles adhere to the outer side of the corrosion layer formed on the grid surface. Subsequent coating, curing, assembly, and charging processes allow the cobalt phosphate to penetrate into the corrosion layer, achieving grid densification and enhancing the bonding strength between the positive electrode grid and the active material, effectively suppressing the softening and shedding of the active material. However, cobalt phosphate inherently has a tendency to agglomerate, and the agglomerated particles cannot be evenly distributed, hindering the full realization of its corrosion resistance and limiting the application effectiveness of this technical solution. Summary of the Invention
[0005] This invention provides a corrosion-resistant lead-based battery plate and its preparation method, which can solve the problem in the prior art that cobalt phosphate itself is prone to agglomeration, which is not conducive to exerting its corrosion resistance performance.
[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing corrosion-resistant lead-based battery plates, comprising the following steps: S1. Prepare a modified cobalt phosphate suspension, heat it, immerse the positive electrode grid in the modified cobalt phosphate suspension, and then cool it to obtain a pretreated positive electrode grid. S2. Dry and cool the pretreated positive electrode grid to obtain the treated positive electrode grid. S3, mix the paste, and prepare the positive electrode lead paste; S4. Apply the positive lead paste obtained in S3 onto the treated positive grid plate obtained in S2, and dry it to obtain the lead-based battery plate.
[0007] Further, in step S1, the method for preparing the positive electrode grid is as follows: Alloy lead is melted and made into lead strips, which are then rolled, punched, and knurled to obtain the positive electrode grid.
[0008] Furthermore, the thickness of the lead strip after rolling is 2.2 to 3.2 mm, and the knurling depth is 0.1 to 0.12 mm.
[0009] Further, in step S1, the modified cobalt phosphate suspension contains the following raw materials in parts by weight: 100 parts deionized water and 2 to 4 parts modified cobalt phosphate.
[0010] Furthermore, the method for preparing the modified cobalt phosphate is as follows: S11, Preparation of N / CDs (nitrogen-doped carbon dots); S12. Add cobalt nitrate hexahydrate and N / CDs to deionized water, sonicate to obtain a mixture; add (NH4)2HPO4 aqueous solution to the mixture, stir, let stand, wash, and dry to obtain N / CDs-cobalt phosphate. S13. Add N / CDs-cobalt phosphate and γ-mercaptopropyltrimethoxysilane to an aqueous ethanol solution, stir, let stand, wash, and dry to obtain modified cobalt phosphate.
[0011] Further, in step S11, the specific steps for preparing N / CDs are as follows: A graphite rod was used as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode. The electrode was inserted into an electrolytic cell containing tetrabutylammonium hydroxide electrolyte. The electrolyzed solution was filtered using a constant potential chronoamperometry method. The filtrate was purified by dialysis and then freeze-dried to obtain N / CDs.
[0012] Furthermore, the concentration of the tetrabutylammonium hydroxide electrolyte is 0.05–0.2 mol / L, and the volume is 20–30 mL; the working voltage of the constant potential chronoamperometry is 3–5 V, and the electrolysis time is 1–2 h; the filtration uses a filter head with a pore size of 0.22–0.45 μm; the dialysis uses a dialysis bag with a molecular weight cutoff of 3500 Da, and the dialysis time is 24–72 h.
[0013] Further, in step S12, the ratio of the amount of deionized water, cobalt nitrate hexahydrate, N / CDs, and (NH4)2HPO4 aqueous solution is 50mL:0.873g:0.216~0.536g:10~20mL; the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:10~20mL.
[0014] Furthermore, in step S12, the ultrasound time is 30-40 minutes; the stirring time is 2-3 hours.
[0015] Further, in step S13, the ratio of N / CDs-cobalt phosphate, γ-mercaptopropyltrimethoxysilane, and ethanol aqueous solution is 1.2g:0.1-0.2g:10mL; the volume fraction of the ethanol aqueous solution is 90%.
[0016] Furthermore, in step S13, the stirring time is 1 to 2 hours.
[0017] Furthermore, in step S1, the heating temperature is 45–55°C; the reheating temperature is 45–55°C.
[0018] Further, in step S2, the specific steps of drying and cooling are as follows: the pretreated positive electrode grid is first placed under conditions of relative humidity of 70% to 80% and temperature of 50 to 60°C for 3 to 5 hours, then placed under conditions of relative humidity of 30% to 40% and temperature of 50 to 60°C for 5 to 8 hours, and finally the temperature is reduced to room temperature within 2 hours under conditions of relative humidity of 30% to 40%.
[0019] Further, in step S3, the specific steps of the paste are as follows: first, mix and stir lead powder and carbon fiber accounting for 0.08% to 0.10% of the lead powder mass, then add water accounting for 12% of the lead powder mass and sulfuric acid accounting for 8% to 9% of the lead powder mass with a specific gravity of 1.40 g / mL to make paste.
[0020] Furthermore, in step S4, the coating time is 6 to 7 hours.
[0021] Secondly, the present invention provides a corrosion-resistant lead-based battery plate, which is prepared by any one of the preparation methods described above.
[0022] The beneficial effects of this invention are: 1. In step S1 of this invention, the positive electrode grid is immersed in a modified cobalt phosphate suspension. The uniform deposition of cobalt phosphate particles on the grid surface, combined with a heating and reheating process, forms a dense cobalt phosphate pre-coating layer on the grid surface. This pre-coating layer effectively isolates the corrosive electrolyte from direct contact with the grid substrate, significantly improving the initial corrosion resistance of the grid. In step S2, a staged temperature and humidity drying and cooling process is used to allow the cobalt phosphate pre-coating layer to slowly solidify and shrink under gradually decreasing humidity and temperature conditions, forming a dense, microcrack-free, and complete protective film. In step S3, a positive electrode lead paste is prepared using a paste-making process to ensure the uniform dispersion of active materials, additives, and fibers in the lead paste, providing a paste with good flowability and adhesion for subsequent coating. In step S4, the prepared positive electrode... Applying lead paste to the treated grid and then drying it allows the lead paste to bond tightly with the modified cobalt phosphate protective film on the grid surface. The active groups on the modified cobalt phosphate surface can interact with lead ions in the lead paste, significantly improving the interfacial bonding force between the lead paste and the grid. The drying process removes excess moisture from the lead paste, allowing it to solidify and form a structurally stable active material layer. This effectively reduces the risk of softening and shedding of the positive electrode active material during battery charge-discharge cycles. Furthermore, the high conductivity of the modified cobalt phosphate optimizes the electron transport efficiency of the plate and reduces interfacial impedance. Ultimately, this step organically combines the corrosion resistance of the grid with the electrochemical performance of the lead paste, resulting in a lead-based battery plate that combines excellent corrosion resistance, structural stability, and electrochemical performance.
[0023] 2. This invention creatively incorporates modified cobalt phosphate. In step S11, the introduction of nitrogen-doped carbon dots (N / CDs) firstly utilizes nitrogen atom doping to effectively regulate the electronic structure of the carbon dots, introducing active sites such as pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen into the carbon framework, significantly improving the intrinsic conductivity of the carbon dots. Simultaneously, the nitrogen-containing functional groups introduced by nitrogen doping can form coordination interactions with cobalt ions on the surface of cobalt phosphate, allowing the carbon dots to be uniformly anchored on the surface of the cobalt phosphate particles. Through steric hindrance and electrostatic repulsion, the agglomeration of cobalt phosphate particles is effectively prevented, greatly improving its dispersion stability in the slurry. In step S12, N / CDs are in situ combined with cobalt nitrate and diammonium hydrogen phosphate. Co-precipitation allows nitrogen-doped carbon dots to be uniformly embedded within and on the surface of cobalt phosphate particles, forming an N / CDs / cobalt phosphate composite material. This not only enhances the electron transport capability of cobalt phosphate through the high conductivity of the nitrogen-doped carbon dots, but also provides reaction sites for subsequent silane grafting using the active groups such as amino and carboxyl groups on the carbon dot surface. In step S13, γ-mercaptopropyltrimethoxysilane is used to modify the surface of the composite material. The silane end condenses with the hydroxyl groups on the N / CDs-cobalt phosphate surface to form a strong chemical bond, while the mercapto (-SH) group acts as a functional terminal, forming a strong coordination bond (Pb-S) with lead ions in the positive electrode paste, significantly enhancing the interfacial bonding between cobalt phosphate and the lead paste. The synergistic effect of these three steps ultimately yields modified cobalt phosphate with excellent dispersibility, high conductivity, and strong interfacial bonding, providing durable corrosion protection for the electrode plate and improving the cycle performance of the battery. Detailed Implementation
[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.
[0025] In a first aspect, the present invention provides a method for preparing corrosion-resistant lead-based battery plates, comprising the following steps: S1. Prepare a modified cobalt phosphate suspension, heat it, immerse the positive electrode grid in the modified cobalt phosphate suspension, and then cool it to obtain a pretreated positive electrode grid. The above steps involve immersing the positive electrode grid in a modified cobalt phosphate suspension and heating it back to room temperature. By utilizing the uniform deposition and thermal diffusion of cobalt phosphate particles on the grid surface, a dense and continuously distributed cobalt phosphate pre-coating layer is formed on the grid surface. This pre-coating layer acts as a physical barrier, effectively isolating the corrosive electrolyte from direct contact with the grid substrate, inhibiting the corrosion reaction of the grid from the source, and laying the interfacial foundation for the firm bonding of the subsequent coating with the substrate. S2. Dry and cool the pretreated positive electrode grid to obtain the treated positive electrode grid. The above steps involve a phased temperature and humidity drying and cooling process, which allows the cobalt phosphate pre-coating layer to slowly solidify and shrink under gradually decreasing humidity and temperature conditions, forming a dense and intact protective film without microcracks. S3, mix the paste, and prepare the positive electrode lead paste; The above steps involve uniformly mixing lead powder, additives, fibers, and other raw materials with sulfuric acid and water through a paste-making process to prepare a positive electrode lead paste with suitable fluidity and adhesion. This ensures that the active material is uniformly coated on the grid surface without layering, providing a guarantee for the formation of a stable active material network after subsequent curing and drying. S4. Apply the positive lead paste obtained in S3 onto the treated positive grid plate obtained in S2, and dry it to obtain the lead-based battery plate.
[0026] The above steps involve coating the positive electrode lead paste onto the treated grid and drying it, which allows the lead paste to bond tightly with the modified cobalt phosphate protective film on the grid surface, improving the interfacial bonding force, solidifying the lead paste to form a stable active material layer, reducing the risk of active material shedding, and optimizing electron transport by utilizing the conductivity of carbon dots, ultimately obtaining a lead-based battery plate with excellent comprehensive performance.
[0027] In some embodiments, the method for preparing the positive electrode grid in step S1 is as follows: Alloy lead is melted and made into lead strips, which are then rolled, punched, and knurled to obtain the positive electrode grid.
[0028] By melting alloy lead and then rolling, punching, and knurling to prepare the positive electrode grid, the continuous casting and rolling process is used to refine the grid grains and improve its mechanical strength and surface roughness. This not only enhances the grid's own corrosion resistance, but also significantly improves the interfacial bonding force with the subsequent cobalt phosphate coating and lead paste through the micro-anchoring points formed by knurling, thus providing structural protection for the long-term stable operation of the electrode plate.
[0029] In some embodiments, the thickness of the lead strip after roll forming is 2.2–3.2 mm, and the knurling depth is 0.1–0.12 mm. This thickness range ensures that the grid has sufficient mechanical strength to support the active material, while avoiding excessive thickness that would increase grid resistance and weight. At the same time, this knurling depth can form a uniform micro-anchoring structure, effectively enhancing the bonding force between the cobalt phosphate coating and the grid. If the thickness is too small, the grid will lack strength and be prone to deformation and breakage; if the thickness is too large, it will increase internal resistance and cost. If the knurling depth is too shallow, the anchoring effect will be insufficient and the coating will be prone to peeling off; if the depth is too deep, it may cause local stress concentration in the grid and reduce its corrosion resistance.
[0030] In some embodiments, in step S1, the modified cobalt phosphate suspension comprises the following parts by weight of raw materials: 100 parts deionized water and 2-4 parts modified cobalt phosphate. This ratio ensures uniform dispersion of the suspension, avoids particle agglomeration, and ensures a uniform and dense pre-coating layer. If too much modified cobalt phosphate is used, the coating will be too thick, prone to cracking, and have reduced adhesion. If too little is used, an effective protective layer cannot be formed, both of which will reduce corrosion resistance and cycle stability.
[0031] In some embodiments, the method for preparing the modified cobalt phosphate is as follows: S11, Preparation of N / CDs; S12. Add cobalt nitrate hexahydrate and N / CDs to deionized water, sonicate to obtain a mixture; add (NH4)2HPO4 aqueous solution to the mixture, stir, let stand, wash, and dry to obtain N / CDs-cobalt phosphate. In a deionized water system, cobalt nitrate hexahydrate dissociates into cobalt ions, which then coordinate with phosphate ions provided by diammonium hydrogen phosphate to generate a cobalt phosphate precursor. N / CDs act as a carrier and nucleation site, anchoring themselves at the growth interface of cobalt phosphate through coordination and hydrogen bonding, inhibiting the aggregation of cobalt phosphate particles and achieving uniform dispersion. After stirring and settling, a precipitate forms in the reaction system. After washing to remove soluble impurities and drying, a nitrogen-doped carbon dot in-situ composite cobalt phosphate material is obtained, achieving uniform composite of N / CDs and cobalt phosphate, and improving the dispersibility and structural stability of the material.
[0032] S13. Add N / CDs-cobalt phosphate and γ-mercaptopropyltrimethoxysilane to an aqueous ethanol solution, stir, let stand, wash, and dry to obtain modified cobalt phosphate.
[0033] N / CDs-cobalt phosphate undergoes hydrolysis and condensation reactions with γ-mercaptopropyltrimethoxysilane in an aqueous ethanol solution: the trimethoxysilane group of γ-mercaptopropyltrimethoxysilane hydrolyzes in the aqueous solution to generate silanol groups, which then undergo dehydration condensation reactions with the hydroxyl groups (-OH) on the surface of N / CDs-cobalt phosphate to form stable covalent bonds; at the same time, the thiol and other functional groups in the silane molecule are retained on the material surface, achieving surface modification of cobalt phosphate through chemical bonding. Finally, after washing and drying, surface-functionalized modified cobalt phosphate is obtained, endowing the material with excellent interfacial bonding ability and dispersibility.
[0034] In some embodiments, the specific steps for preparing N / CDs in step S11 are as follows: A graphite rod was used as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode. The electrode was inserted into an electrolytic cell containing tetrabutylammonium hydroxide electrolyte. The electrolyzed solution was filtered using a potentiostatic chronoamperometry method. The filtrate was purified by dialysis and freeze-dried to obtain N / CDs. The N / CDs prepared by this method can effectively improve the material's conductivity, interfacial bonding, and corrosion resistance, and significantly enhance the electrochemical stability and functionality of the electrode / composite material.
[0035] In some embodiments, the concentration of the tetrabutylammonium hydroxide electrolyte is 0.05–0.2 mol / L, and the volume is 20–30 mL; the working voltage of the potentiostatic chronoamperometry is 3–5 V, and the electrolysis time is 1–2 h; the filtration uses a filter head with a pore size of 0.22–0.45 μm; the dialysis uses a dialysis bag with a molecular weight cutoff of 3500 Da, and the dialysis time is 24–72 h. This invention, by optimizing the electrolyte concentration, electrolysis parameters, and post-processing, can efficiently prepare high-purity, well-dispersed nitrogen-doped carbon dots, effectively improving the conductivity and electrochemical stability of the electrode material; deviations from the optimal parameter range will lead to decreased product yield, morphological deterioration, or deterioration of interfacial properties.
[0036] In some embodiments, in step S12, the ratio of deionized water, cobalt nitrate hexahydrate, N / CDs, and (NH4)2HPO4 aqueous solution is 50 mL: 0.873 g: 0.216–0.536 g: 10–20 mL; the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264 g: 10–20 mL. This allows for precise control of the product's morphology and properties. Excessive dosage can easily lead to product aggregation and performance degradation, while insufficient dosage results in insufficient yield of the target product and difficulty in meeting performance standards.
[0037] In some embodiments, in step S12, the ultrasonic time is 30-40 minutes; the stirring time is 2-3 hours. This allows the materials to be fully mixed and dispersed, ensuring the uniformity of the system. If the ultrasonic time is too short, the materials will not be sufficiently dispersed; if it is too long, it will easily lead to increased energy consumption and damage to the structure of some components. If the stirring time is too short, the materials cannot be mixed uniformly; if it is too long, it will prolong the process cycle and increase production costs.
[0038] In some embodiments, in step S13, the ratio of N / CDs-cobalt phosphate, γ-mercaptopropyltrimethoxysilane, and ethanol aqueous solution is 1.2g:0.1-0.2g:10mL; the volume fraction of the ethanol aqueous solution is 90%. This ensures that the modification reaction proceeds fully and improves product performance; too little silane will lead to insufficient modification effect, while too much will easily cause waste of raw materials and increase side reactions; deviation of the ethanol aqueous solution from the ratio will change the concentration of the reaction system, affecting reaction efficiency and product stability.
[0039] In some embodiments, the stirring time in step S13 is 1 to 2 hours. This ensures that the modification reaction occurs uniformly and that the silane and substrate are fully bonded. Too short a stirring time will result in insufficient reaction and weak bonding, while too long a stirring time will increase the processing time and may also damage the modified layer structure and reduce product performance.
[0040] In some embodiments, in step S1, the heating temperature is 45–55°C; the reheating temperature is 45–55°C. This can gently activate the reactivity of the material, avoiding material deterioration due to high temperatures and excessively slow reaction rates due to low temperatures; excessively high temperatures can easily cause material decomposition and side reactions, while excessively low temperatures result in low reaction efficiency and failure to achieve the expected process results.
[0041] In some embodiments, the specific steps of drying and cooling in step S2 are as follows: the pretreated positive electrode grid is first placed under conditions of 70%–80% relative humidity and 50–60°C for 3–5 hours, then placed under conditions of 30%–40% relative humidity and 50–60°C for 5–8 hours, and finally the temperature is reduced to room temperature within 2 hours under conditions of 30%–40% relative humidity. Staged drying and cooling can prevent defects such as cracking and deformation of the positive electrode grid due to sudden changes in temperature and humidity, ensuring the integrity of the grid structure. Improper humidity / temperature control, excessively long placement time, or excessively rapid cooling can lead to surface cracking and uneven internal stress in the grid, reducing product qualification rate and service life.
[0042] In some embodiments, step S3 involves the following steps for preparing the paste: first, lead powder and 0.08%–0.10% carbon fiber (by weight of lead powder) are mixed and stirred; then, 12% water (by weight of lead powder) and 8%–9% sulfuric acid (by weight of lead powder) with a specific gravity of 1.40 g / mL are added to prepare the paste. This process optimizes the formability and electrochemical performance of the lead paste. Deviations in the amount of carbon fiber will affect the conductivity of the lead paste; improper sulfuric acid dosage / specific gravity will lead to insufficient activity or poor adhesion of the lead paste; and an imbalance in the paste ratio will reduce the electrochemical performance and lifespan of the electrode plate.
[0043] In some embodiments, the coating time in step S4 is 6-7 hours. This ensures uniform coating and electrode plate forming quality, and avoids material drying and uneven coating. Too short a coating time will result in incomplete coating and uneven thickness, while too long a time will cause the lead paste to dry out, affecting the bonding force between the electrode plate and the grid and reducing product performance.
[0044] Secondly, the present invention provides a corrosion-resistant lead-based battery plate, which is prepared by any one of the preparation methods described above.
[0045] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0046] Preparation Example 1 The method for preparing modified cobalt phosphate in this preparation example is as follows: S11. Using a 10cm graphite rod as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode, the electrode was inserted into an electrolytic cell containing 20mL of 0.1mol / L tetrabutylammonium hydroxide electrolyte. The electrolysis was performed using the constant potential chronoamperometry method, with the working voltage set to 5V for 1h. After electrolysis, the resulting solution was filtered through a filter with a pore size of 0.22μm. The filtrate was dialyzed through a dialysis bag with a molecular weight cutoff of 3500Da for 48h. Finally, the solution was freeze-dried to obtain N / CDs. S12. Add 0.873g of cobalt nitrate hexahydrate and 0.216g of N / CDs to 50mL of deionized water, and sonicate for 30min to obtain a mixture; add 15mL of (NH4)2HPO4 aqueous solution (the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:15mL) to the mixture, stir for 2h, let stand, wash, and dry to obtain N / CDs-cobalt phosphate; S13. Add 1.2g of N / CDs-cobalt phosphate and 0.1g of γ-mercaptopropyltrimethoxysilane to 10mL of 90% ethanol aqueous solution, stir for 1h, let stand, wash, and dry to obtain modified cobalt phosphate.
[0047] Preparation Example 2 The method for preparing modified cobalt phosphate in this preparation example is as follows: S11. Using a 10cm graphite rod as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode, the electrode was inserted into an electrolytic cell containing 20mL of 0.1mol / L tetrabutylammonium hydroxide electrolyte. The electrolysis was performed using the constant potential chronoamperometry method, with the working voltage set to 5V for 1h. After electrolysis, the resulting solution was filtered through a filter with a pore size of 0.22μm. The filtrate was dialyzed through a dialysis bag with a molecular weight cutoff of 3500Da for 48h. Finally, the solution was freeze-dried to obtain N / CDs. S12. Add 0.873g of cobalt nitrate hexahydrate and 0.376g of N / CDs to 50mL of deionized water, and sonicate for 35min to obtain a mixture; add 15mL of (NH4)2HPO4 aqueous solution (the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:15mL) to the mixture, stir for 2.5h, let stand, wash, and dry to obtain N / CDs-cobalt phosphate; S13. Add 1.2g of N / CDs-cobalt phosphate and 0.15g of γ-mercaptopropyltrimethoxysilane to 10mL of 90% ethanol aqueous solution, stir for 1.5h, let stand, wash, and dry to obtain modified cobalt phosphate.
[0048] Preparation Example 3 The method for preparing modified cobalt phosphate in this preparation example is as follows: S11. Using a 10cm graphite rod as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode, the electrode was inserted into an electrolytic cell containing 20mL of 0.1mol / L tetrabutylammonium hydroxide electrolyte. The electrolysis was performed using the constant potential chronoamperometry method, with the working voltage set to 5V for 1h. After electrolysis, the resulting solution was filtered through a filter with a pore size of 0.22μm. The filtrate was dialyzed through a dialysis bag with a molecular weight cutoff of 3500Da for 48h. Finally, the solution was freeze-dried to obtain N / CDs. S12. Add 0.873g of cobalt nitrate hexahydrate and 0.536g of N / CDs to 50mL of deionized water, and sonicate for 40min to obtain a mixture; add 15mL of (NH4)2HPO4 aqueous solution (the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:15mL) to the mixture, stir for 3h, let stand, wash, and dry to obtain N / CDs-cobalt phosphate; S13. Add 1.2g of N / CDs-cobalt phosphate and 0.2g of γ-mercaptopropyltrimethoxysilane to 10mL of 90% ethanol aqueous solution, stir for 2h, let stand, wash, and dry to obtain modified cobalt phosphate.
[0049] Compare with Example 1 The only difference between this comparative example and preparation example 1 is that γ-mercaptopropyltrimethoxysilane is omitted. The specific steps are as follows: S11. Using a 10cm graphite rod as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode, the electrode was inserted into an electrolytic cell containing 20mL of 0.1mol / L tetrabutylammonium hydroxide electrolyte. The constant potential chronoamperometry method was used, and the working voltage was set to 3-5V. Electrolysis was carried out for 1h. After electrolysis, the resulting solution was filtered through a filter with a pore size of 0.22μm. The filtrate was dialyzed through a dialysis bag with a molecular weight cutoff of 3500Da for 48h. Finally, the solution was freeze-dried to obtain N / CDs. S12. Add 0.873g of cobalt nitrate hexahydrate and 0.216g of N / CDs to 50mL of deionized water, and sonicate for 30min to obtain a mixture. Add 15mL of (NH4)2HPO4 aqueous solution (the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:15mL) to the mixture, stir for 2h, let stand, wash, and dry to obtain modified cobalt phosphate.
[0050] Compare with Example 2 The only difference between this comparative example and preparation example 1 is that γ-mercaptopropyltrimethoxysilane and nitrogen doping are omitted. The specific steps are as follows: S11. Using a 10cm graphite rod as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode, the electrode was inserted into an electrolytic cell containing 20mL of 0.1mol / L sodium hydroxide electrolyte. The constant potential chronoamperometry method was used, and the working voltage was set to 3-5V. Electrolysis was carried out for 1h. After electrolysis, the resulting solution was filtered through a filter with a pore size of 0.22μm. The filtrate was dialyzed through a dialysis bag with a molecular weight cutoff of 3500Da for 48h. Finally, the solution was freeze-dried to obtain CDs. S12. Add 0.873g of cobalt nitrate hexahydrate and 0.216g of CDs to 50mL of deionized water, and sonicate for 30min to obtain a mixture. Add 15mL of (NH4)2HPO4 aqueous solution (the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264g:15mL) to the mixture, stir for 2h, let stand, wash, and dry to obtain modified cobalt phosphate.
[0051] Example 1 This embodiment provides a method for preparing corrosion-resistant lead-based battery plates, including the following steps: S1. The positive electrode alloy lead is made into a lead strip with a thickness of 2.5 mm. After punching, a 6-GF-100 positive grid with a size of 151 mm × 151 mm is obtained. Then, the grid is knurled with a size of 0.5 × 0.5 mm and a depth of 0.12 mm to obtain the positive electrode grid. By mass percentage, 100 parts of pure water and 2 parts of modified cobalt phosphate obtained in Preparation Example 1 are mixed. The suspension temperature is raised to 45°C and the positive electrode grid is placed in the stirred cobalt phosphate suspension. After heating, the water temperature is raised back to 45°C to obtain the pretreated positive electrode grid. S2. Place the pretreated positive electrode grid in a condition of 70% relative humidity and 50℃ for 3 hours, then place it in a condition of 30% relative humidity and 50℃ for 5 hours, and finally lower the temperature to room temperature within 2 hours under a condition of 30% relative humidity to obtain the treated positive electrode grid. S3. First, mix 100kg of lead powder and 0.08% carbon fiber by weight of lead powder. Then, add 12% water by weight of lead powder and 8% sulfuric acid by weight of lead powder with a specific gravity of 1.40g / mL to make a paste and prepare positive electrode lead paste. S4. Apply the positive lead paste obtained in S3 onto the treated positive grid obtained in S2. The coating time is 6 hours. After drying, the lead-based battery plate is obtained.
[0052] Example 2 This embodiment provides a method for preparing corrosion-resistant lead-based battery plates, including the following steps: S1. The positive electrode alloy lead is made into a lead strip with a thickness of 2.5 mm. After punching, a 6-GF-100 positive grid with a size of 151 mm × 151 mm is obtained. Then, the grid is knurled with a size of 0.5 × 0.5 mm and a depth of 0.12 mm to obtain the positive electrode grid. By mass percentage, 100 parts of pure water and 3 parts of modified cobalt phosphate obtained in Preparation Example 1 are mixed. The suspension temperature is heated to 50°C. The positive electrode grid is then placed in the stirred cobalt phosphate suspension. After heating, the water temperature is restored to 50°C to obtain the pretreated positive electrode grid. S2. Place the pretreated positive electrode grid in a condition of 75% relative humidity and 55℃ for 4 hours, then place it in a condition of 35% relative humidity and 55℃ for 7 hours, and finally lower the temperature to room temperature within 2 hours under a condition of 35% relative humidity to obtain the treated positive electrode grid. S3. First, mix 100kg of lead powder and 0.09% carbon fiber (by weight of lead powder) and stir. Then, add 12% water (by weight of lead powder) and 8.5% sulfuric acid (by weight of lead powder) with a specific gravity of 1.40g / mL to form a paste and prepare the positive electrode lead paste. S4. Apply the positive electrode lead paste obtained in S3 onto the treated positive electrode grid obtained in S2. The coating time is 6.5 hours. After drying, the lead-based battery plate is obtained.
[0053] Example 3 This embodiment provides a method for preparing corrosion-resistant lead-based battery plates, including the following steps: S1. The positive electrode alloy lead is made into a lead strip with a thickness of 2.5 mm. After punching, a 6-GF-100 positive grid with a size of 151 mm × 151 mm is obtained. Then, the grid is knurled with a size of 0.5 × 0.5 mm and a depth of 0.12 mm to obtain the positive electrode grid. By mass percentage, 100 parts of pure water and 4 parts of modified cobalt phosphate obtained in Preparation Example 1 are mixed. After heating the suspension to 55°C, the positive electrode grid is placed in the stirred cobalt phosphate suspension. After heating the water temperature back to 55°C, the pretreated positive electrode grid is obtained. S2. Place the pretreated positive electrode grid in a condition of 80% relative humidity and 60℃ for 5 hours, then place it in a condition of 40% relative humidity and 60℃ for 8 hours, and finally lower the temperature to room temperature within 2 hours under a condition of 40% relative humidity to obtain the treated positive electrode grid. S3. First, mix 100 kg of lead powder with 0.10% carbon fiber (by weight of lead powder), then add 12% water (by weight of lead powder) and 9% sulfuric acid (by weight of lead powder) with a specific gravity of 1.40 g / mL to make a paste, thus preparing the positive electrode lead paste. S4. Apply the positive lead paste obtained in S3 onto the treated positive grid obtained in S2. The coating time is 7 hours. After drying, the lead-based battery plate is obtained.
[0054] Example 4 The only difference between this embodiment and Example 3 is that the modified cobalt phosphate obtained in Example 1 is replaced with an equal amount of the modified cobalt phosphate obtained in Example 2.
[0055] Example 5 The only difference between this embodiment and Example 3 is that the modified cobalt phosphate obtained in Example 1 is replaced with an equal amount of the modified cobalt phosphate obtained in Example 3.
[0056] Comparative Example 1 The only difference between this comparative example and Example 1 is that the "modified cobalt phosphate obtained in Preparation Example 1" is replaced with an equal amount of "modified cobalt phosphate obtained in Comparative Example 1".
[0057] Comparative Example 2 The only difference between this comparative example and Example 1 is that the "modified cobalt phosphate obtained in Preparation Example 1" is replaced with an equal amount of "modified cobalt phosphate obtained in Comparative Example 2".
[0058] Comparative Example 3 The only difference between this comparative example and Example 1 is that "cobalt phosphate" was used instead of "the modified cobalt phosphate obtained in Preparation Example 1".
[0059] The corrosion-resistant lead-acid battery plates prepared in Examples 1-5 and Comparative Examples 1-3 were used as positive electrodes, and a commonly used lead-calcium-tin-aluminum alloy grid was used as the negative electrode. The negative electrode lead paste was made by mixing 100 parts lead powder, 2 parts barium sulfate, 0.2 parts sodium lignosulfonate, 0.2 parts carbon black, 10 parts deionized water, and 10 parts 14 mol / L dilute sulfuric acid. The positive and negative electrodes were separated by an AGM separator. The battery was assembled into a prototype battery, and 1.300 g·cm³ of lead-acid battery solution was poured into the battery casing. -3 The H2SO4 solution was used to obtain the battery to be tested. Performance tests were performed on the battery as follows: I. Corrosion Resistance Test: The prototype battery was placed in a 60℃ water bath environment and subjected to a constant current charging corrosion test in series. A μC-XCF08 charge-discharge tester was used for constant current polarization testing, and the apparent corrosion current density of the corroded grid was 2.3 mA·cm². -2 The constant current corrosion time was 300 hours. After the grid corrosion was completed, the corrosion products on the grid surface were removed by soaking in a sugar-alkali solution. The corroded grid was then washed with deionized water, vacuum dried, and weighed (m2). The weight loss of the grid before and after electrochemical corrosion (m1-m2) was calculated, and then the average corrosion rate of the grid was calculated.
[0060] II. Battery Lifespan Test: Referring to GB19638.2-2005 "Stationary Valve-Regulated Sealed Lead-Acid Batteries" standard, the battery underwent an accelerated float charge cycle durability test. The battery was initially tested at 25℃ using a 3-hour rate (C3) capacity test. After fully charging, the battery was charged at 60℃ with a constant voltage of 2.25V / cell for 30 days. Then, the battery was cooled at 25℃ for 24 hours before undergoing a room temperature C3 capacity test. Each test cycle corresponds to one year of float charge lifespan. The test continued until the room temperature C3 capacity fell below 80% of the rated C3 capacity. A battery discharge capacity below 80% of the rated capacity was considered a failure, and the test was terminated. The test results are shown in Table 1.
[0061] Table 1
[0062] As can be seen from Table 1, the corrosion resistance and cycle performance of the batteries prepared in Examples 1-5 of this invention are superior to those in Comparative Examples 1-3.
[0063] Compared with Example 1, Comparative Example 1 omitted γ-mercaptopropyltrimethoxysilane, and its overall performance was lower than that of Example 1. This indicates that γ-mercaptopropyltrimethoxysilane modifies the surface of the composite material. The silane end condenses with the hydroxyl groups on the surface of N / CDs-cobalt phosphate to form a strong chemical bond, and the mercapto group (-SH) acts as a functional end that can form a strong coordination bond (Pb-S) with the lead ions in the positive electrode lead paste, which significantly enhances the interfacial bonding force between cobalt phosphate and lead paste and can improve the overall performance of the battery.
[0064] Compared with Example 1, Comparative Example 2 omitted γ-mercaptopropyltrimethoxysilane and nitrogen doping, and its overall performance was lower than that of Example 1. This shows that nitrogen doping can effectively regulate the electronic structure of carbon dots, introduce active sites such as pyridine nitrogen, pyrrole nitrogen and graphitic nitrogen into the carbon framework, significantly improve the intrinsic conductivity of carbon dots, and at the same time, the nitrogen-containing functional groups introduced by nitrogen doping can form coordination with cobalt ions on the surface of cobalt phosphate, so that the carbon dots are uniformly anchored on the surface of cobalt phosphate particles. Through steric hindrance effect and electrostatic repulsion, the aggregation of cobalt phosphate particles is effectively prevented, greatly improving its dispersion stability in the slurry, and ultimately improving the overall performance of the battery.
[0065] Comparative Example 3 used unmodified cobalt phosphate, which had poor dispersibility, low bonding strength, and the worst overall performance.
[0066] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A method for preparing corrosion-resistant lead-based battery plates, characterized in that, Includes the following steps: S1. Prepare a modified cobalt phosphate suspension, heat it, immerse the positive electrode grid in the modified cobalt phosphate suspension, and then cool it to obtain a pretreated positive electrode grid. S2. Dry and cool the pretreated positive electrode grid to obtain the treated positive electrode grid. S3, mix the paste, and prepare the positive electrode lead paste; S4. Apply the positive lead paste obtained in S3 onto the treated positive grid plate obtained in S2, and dry it to obtain the lead-based battery plate.
2. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, In step S1, the method for preparing the positive electrode grid is as follows: Alloy lead is melted and made into lead strips, which are then rolled, punched, and knurled to obtain the positive electrode grid. The thickness of the lead strip after rolling is 2.2 to 3.2 mm, and the knurling depth is 0.1 to 0.12 mm.
3. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, In step S1, the modified cobalt phosphate suspension contains the following raw materials in parts by weight: 100 parts deionized water and 2 to 4 parts modified cobalt phosphate.
4. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, The method for preparing the modified cobalt phosphate is as follows: S11, Preparation of N / CDs; S12. Add cobalt nitrate hexahydrate and N / CDs to deionized water, sonicate to obtain a mixture; add (NH4)2HPO4 aqueous solution to the mixture, stir, let stand, wash, and dry to obtain N / CDs-cobalt phosphate. S13. Add N / CDs-cobalt phosphate and γ-mercaptopropyltrimethoxysilane to an aqueous ethanol solution, stir, let stand, wash, and dry to obtain modified cobalt phosphate.
5. The method for preparing corrosion-resistant lead-based battery plates according to claim 4, characterized in that, In step S11, the specific steps for preparing N / CDs are as follows: A graphite rod was used as the working electrode, a platinum wire as the counter electrode, and a calomel electrode as the reference electrode. The electrode was inserted into an electrolytic cell containing tetrabutylammonium hydroxide electrolyte. The electrolyzed solution was filtered using a constant potential chronoamperometry method. The filtrate was purified by dialysis and then freeze-dried to obtain N / CDs. The concentration of the tetrabutylammonium hydroxide electrolyte is 0.05–0.2 mol / L, and the volume is 20–30 mL; The operating voltage of the constant potential chronoamperometry method is 3-5V, and the electrolysis time is 1-2h. The filtration uses a filter head with a pore size of 0.22–0.45 μm; The dialysis was performed using a dialysis bag with a molecular weight cutoff of 3500 Da, and the dialysis time was 24–72 hours.
6. The method for preparing corrosion-resistant lead-based battery plates according to claim 4, characterized in that, In step S12, the ratio of deionized water, cobalt nitrate hexahydrate, N / CDs, and (NH4)2HPO4 aqueous solution is 50 mL: 0.873 g: 0.216–0.536 g: 10–20 mL; the ratio of (NH4)2HPO4 to deionized water in the (NH4)2HPO4 aqueous solution is 0.264 g: 10–20 mL. In step S12, the ultrasound time is 30-40 minutes; the stirring time is 2-3 hours. In step S13, the ratio of N / CDs-cobalt phosphate, γ-mercaptopropyltrimethoxysilane, and ethanol aqueous solution is 1.2g:0.1-0.2g:10mL; the volume fraction of the ethanol aqueous solution is 90%. In step S13, the stirring time is 1 to 2 hours.
7. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, In step S1, the heating temperature is 45-55°C; the reheating temperature is 45-55°C.
8. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, In step S2, the specific steps of drying and cooling are as follows: the pretreated positive electrode grid is first placed under conditions of relative humidity of 70% to 80% and temperature of 50 to 60°C for 3 to 5 hours, then placed under conditions of relative humidity of 30% to 40% and temperature of 50 to 60°C for 5 to 8 hours, and finally the temperature is reduced to room temperature within 2 hours under conditions of relative humidity of 30% to 40%.
9. The method for preparing corrosion-resistant lead-based battery plates according to claim 1, characterized in that, In step S3, the specific steps of the paste are as follows: first, mix and stir lead powder and carbon fiber accounting for 0.08% to 0.10% of the lead powder mass, then add water accounting for 12% of the lead powder mass and sulfuric acid accounting for 8% to 9% of the lead powder mass with a specific gravity of 1.40 g / mL to make paste; In step S4, the coating time is 6 to 7 hours.
10. A corrosion-resistant lead-based battery plate, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.