Method for improving initial capacity and cycling stability of positive electrode of lead-carbon battery

Abstract

The invention relates to a method for improving initial capacity and cycling stability of a positive electrode of a lead-carbon battery, and belongs to the technical field of lead-carbon batteries. The lead-carbon battery positive electrode additive with the proton buffering function is adopted, and the additive is prepared from, by mass, 80%-90% of lead powder, 0.1%-1.0% of nucleating agent, 0.1%-0.5% of short fiber, 0.2%-0.6% of conductive agent, 0.3%-0.8% of conductive polymer, 0.5%-2.0% of poising agent, 4.0%-8.0% of sulfuric acid and 8.0%-12.0% of deionized water. The nucleating agent is one or more of SnSO4, tetrabasic lead sulfate and CaSO4; the poising agent is hierarchical pore channel SiO2 modified by a proton carrier, and the proton carrier is-OH,-COOH,-NH2 or-H2PO4. The lead-carbon battery positive electrode additive promotes the substance conversion efficiency and crystal nucleus growth in curing and formation, and the charging acceptance of the lead-carbon battery is remarkably improved; the lead paste is subjected to dual effects of the poising agent in the formation process, so that the conversion efficiency of positive active substances in the formation period is improved, and the initial capacity and service life of the battery positive electrode are improved.

Description

Technical Field

[0001] This invention relates to a method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery, belonging to the field of lead-carbon battery technology. Background Technology

[0002] The energy storage involved in the cathode of a lead-carbon battery is essentially a material conversion between PbO2 and PbSO4, requiring sufficient H+ and HSO4. − Ions complete the reaction, as shown in the reaction equation: ; However, in the positive electrode plates of traditional lead-carbon batteries, the thick plate design and high loading of active materials severely limit the application of H2SO4 electrolyte and H2SO4. + and HSO4 − Mass transfer within the active material results in a high concentration gradient of H2SO4 electrolyte and ions, leading to slow PbO2 / PbSO4 conversion kinetics. In particular, the internal active material cannot be fully utilized, resulting in low utilization efficiency of the positive electrode active material and further limiting the cycle life of lead-carbon batteries.

[0003] Currently, several methods are used to improve the cycle performance of lead-carbon battery cathodes: 1. Improving corrosion resistance and enhancing cycle performance by changing the alloy composition of the cathode grid; 2. Electroplating a film layer on the grid surface, using ceramic or corrosion-resistant films to reduce electrolyte corrosion of the plates. Introducing functional additives into the cathode active material is an important means to improve the specific capacity and cycle life of lead-carbon batteries. Cathode additives are mainly divided into three types: porous additives, conductive additives, and nucleating additives. Influenced by the development of high-energy-density batteries such as lithium-ion and sodium-ion batteries, current industrial lead-carbon battery cathodes, in pursuit of high capacity and high conversion rates, have begun to increase the lead paste loading and introduce large amounts of conductive and porous additives, thus neglecting the importance of cathode cycle stability. Summary of the Invention

[0004] To address the issues of high internal electrolyte and ion gradients caused by thick electrode design and high active material loading in traditional lead-carbon battery manufacturing, this invention provides a method to improve the initial capacity and cycle stability of the lead-carbon battery cathode. By employing a highly stable lead-carbon battery cathode additive with proton buffering function, the method not only promotes material conversion efficiency and improves the conductivity between active materials, but also weakens the high internal ion concentration gradient present in the thick electrode design of lead-carbon batteries. This reduces the limitation of mass transfer kinetics and water loss during charge and discharge, thereby improving the cycle life of lead-carbon batteries during deep charge and discharge processes.

[0005] A method for improving the initial capacity and cycle stability of a lead-carbon battery cathode: An additive for a lead-carbon battery cathode with proton buffering function is used. Based on 100% by mass, the additive contains 80-90% lead powder, 0.1-1.0% nucleating agent, 0.1-0.5% short fiber, 0.2-0.6% conductive agent, 0.3-0.8% conductive polymer, 0.5-2.0% balancing agent, 4.0-8.0% sulfuric acid, and 8.0-12.0% deionized water. The nucleating agent is one or more of SnSO4, tetrabasic lead sulfate, and CaSO4; The balancing agent is a proton-modified hierarchical porous SiO2; the proton carrier is -OH, -COOH, -NH2, or -H2PO4; the balancing agent (proton-modified hierarchical porous SiO2) is directly added to the positive electrode lead paste as an additive, utilizing its porous structure to construct electrolyte transport channels within the active material, promoting H2PO4 uptake. + The movement of ions into the interior of the positive electrode active material, while utilizing the proton carrier function of the functionalized groups on the surface, can act as a proton reservoir to store / release additional H+. + Ions reduce the ion concentration gradient inside the thick electrode, improve the conversion efficiency inside the positive electrode active material, and increase the cycle life of the electrode plate (see...). Figure 5 ).

[0006] Preferably, the short fibers are polypropylene fibers, polyacrylonitrile fibers, polyester fibers, or polyethylene fibers.

[0007] Preferably, the conductive agent is graphene, carbon nanotubes, graphite, or conductive carbon black.

[0008] Preferably, the conductive polymer is one or more of polyaniline, polypyrrole, and polythiophene.

[0009] Preferably, the preparation method of the balancing agent includes the following specific steps: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; 2) Pre-treated multi-level porous SiO2 is added to an acid solution for activation treatment, washed with deionized water, and dried to obtain activated SiO2; 3) Add activated SiO2 to a silane coupling agent / ethanol solution, stir and react at room temperature for 2-4 hours, heat to 40-80℃ and stir and react for 4-8 hours, cool to room temperature and continue stirring and react for 2-4 hours, wash with deionized water and dry to obtain the equilibration agent, namely, multi-level porous SiO2 modified by proton carrier.

[0010] More preferably, the acid solution in step 2) is sulfuric acid, hydrochloric acid, or nitric acid.

[0011] More preferably, the concentration of the acid solution is 0.2~0.6 mol / L.

[0012] More preferably, the silane coupling agent in step 3) is one or more of 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, vinyltriethoxysilane, and (3-propyl phosphate)triethoxysilane.

[0013] More preferably, the preparation method of the multi-level porous SiO2 includes the following specific steps: A silicon source and a surfactant are added to an emulsifier solution to obtain a mixed solution. The mixed solution is stirred and reacted for 2-6 hours, then dehydrated and calcined at high temperature to remove the pore template and organic matter, thus obtaining multi-level porous SiO2.

[0014] Preferably, the emulsifier is polystyrene, polymethyl methacrylate, polyvinyl alcohol, high internal phase emulsion, or Pickering solid particle emulsion; the silicon source is one or more of sodium silicate, tetraethyl orthosilicate, aminosilane, silicon powder, and tetramethyl orthosilicate; and the surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethyl bromide, polyoxyethylene polyoxypropylene ether triblock copolymer, polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, and betaine.

[0015] Preferably, the concentration of the emulsifier solution is 0.1~0.8 mol / L; the concentration of the silicon source in the mixed solution is 0.1~1.2 mol / L, and the concentration of the surfactant is 0.1~0.5 mol / L.

[0016] Preferably, the high-temperature calcination temperature is 400~800℃ and the time is 4~8h.

[0017] The principle behind this invention for improving the initial capacity and cycle stability of the positive electrode in lead-carbon batteries is as follows: In the initial stage of battery operation, the balancer utilizes the lone pairs of electrons present in the loaded proton functional groups or the protons carried by the groups themselves to increase battery capacity. During charge and discharge, the proton functional groups can store / release additional H+. + Ions act as a proton storage medium, and simultaneously utilize their multi-level porous structure to continuously supply electrolyte to the positive electrode active material. This dual effect further enhances the conversion efficiency of the active material within the positive electrode, increasing the initial capacity of the battery. In the later stages of cycling, because SiO2 is inorganic, its inability to react with sulfuric acid electrolyte allows it to remain stable during cycling without being corroded or destroyed. Therefore, it continuously generates a gain effect, slowing down the grain growth rate and thus improving the cycle stability of the electrode plates.

[0018] The beneficial effects of this invention are: (1) The present invention uses a lead-carbon battery cathode additive with proton buffering function, which can promote the material conversion efficiency and crystal nucleus growth during solidification and formation, and significantly improve the charge acceptance of lead-carbon batteries by up to about 40%; (2) The balancer in the lead-carbon battery cathode additive of the present invention can construct electrolyte transport channels inside the active material, and the functionalized groups on the surface have the function of proton carriers, which can act as a proton storage device to store / release additional H+. + Ions reduce the high internal ion concentration gradient in the thick electrode design of lead-carbon batteries, reduce the limitation of mass transfer kinetics and water loss during charge and discharge, and improve the cycle life of lead-carbon batteries during deep charge and discharge. Under 0.5C conditions, the capacity retention rate is maintained at more than 120% after 120 cycles, and the inside of the plate is still moist and retains acid after cycling, reducing the cycle water loss rate by about 10%. (3) The method of the present invention can solve the problem of high internal electrolyte and ion gradient caused by thick plate design and high active material loading in the traditional lead-carbon battery manufacturing process, and improve the material conversion efficiency and cycle life of the positive electrode active material. Attached Figure Description

[0019] Figure 1 SEM and TEM images of multi-level porous SiO2 in Examples 1-3; Figure 2 The FT-IR spectrum of hydroxylated hierarchical porous SiO2 nanospheres in Example 5; Figure 3 The discharge curves of lead-carbon batteries used as the control group, comparative examples 1-2, and examples 1-2 are shown. Figure 4 Cycle performance of lead-carbon batteries used as control group, comparative examples 1-2, and examples 1-2; Figure 5 This is a schematic diagram of the mechanism of balancer additives in the positive electrode of a lead-carbon battery. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0021] Example: A method for improving the initial capacity and cycle stability of a lead-carbon battery cathode, using an additive for a lead-carbon battery cathode with proton buffering function. The additive, by mass, contains 80-90% lead powder, 0.1-1.0% nucleating agent, 0.1-0.5% short fiber, 0.2-0.6% conductive agent, 0.3-0.8% conductive polymer, 0.5-2.0% balancing agent, 4.0-8.0% sulfuric acid, and 8.0-12.0% deionized water. The additive composition content of Examples 1-9 and Comparative Examples 1-3 is shown in Table 1. Table 1. Additive component content of Examples 1-9 and Comparative Examples 1-3 ; The preparation methods of the balancing agents in Examples 1-3 are as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (sodium silicate) and a surfactant (sodium dodecyl sulfate) were added to an emulsifier solution (polystyrene aqueous solution) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 600℃ for 4 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.2 mol / L; the concentration of the silicon source in the mixed solution was 0.5 mol / L, and the concentration of the surfactant was 0.3 mol / L. SEM and TEM images of hierarchical porous SiO2 are shown below. Figure 1 ,from Figure 1 As can be seen, the SiO2 used in the examples has a mesoporous structure, with particles that are spherical in shape with a diameter of approximately 170 nm, and the TEM images further confirm this shape and structure. Additionally, mesoporous features were detected in the TEM images, which facilitates the rapid movement of the sulfuric acid electrolyte. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.2 mol / L sulfuric acid solution) for activation treatment for 30 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (vinyltriethoxysilane) / ethanol solution, stirred at room temperature for 2 hours, heated to 60°C and stirred for 4 hours, cooled to room temperature and stirred for 2 hours, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (hydroxyl)).

[0022] The preparation method of the balancing agent in Example 4 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (tetraethyl orthosilicate) and a surfactant (sodium dodecylbenzenesulfonate) were added to an emulsifier solution (aqueous polymethyl methacrylate) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 600℃ for 6 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.2 mol / L; the concentration of the silicon source in the mixed solution was 0.5 mol / L, and the concentration of the surfactant was 0.3 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.25 mol / L sulfuric acid solution) for 30 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (3-aminopropyltrimethoxysilane) / ethanol solution, stirred at room temperature for 2 hours, heated to 60°C and stirred for 6 hours, cooled to room temperature and stirred for 2 hours, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (carboxyl group)).

[0023] The preparation method of the balancing agent in Example 5 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (aminosilane) and a surfactant (hexadecyltrimethylbromide) were added to an emulsifier solution (polyvinyl alcohol aqueous solution) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 600℃ for 6 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.2 mol / L; the concentration of the silicon source in the mixed solution was 0.5 mol / L, and the concentration of the surfactant was 0.3 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.25 mol / L sulfuric acid solution) for 30 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (vinyltriethoxysilane) / ethanol solution, stirred at room temperature for 2 hours, heated to 60°C and stirred for 6 hours, cooled to room temperature and stirred for 2 hours, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (hydroxyl)).

[0024] The preparation method of the balancing agent in Example 6 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (silicon powder) and a surfactant (polyoxyethylene polyoxypropylene ether triblock copolymer (F127)) were added to an emulsifier solution (high internal phase emulsion) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 800℃ for 4 hours to remove the pore template and organic matter, resulting in hierarchical porous SiO2. The concentration of the emulsifier solution was 0.5 mol / L; the concentration of the silicon source in the mixed solution was 0.8 mol / L, and the concentration of the surfactant was 0.2 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.3 mol / L nitric acid solution) for 50 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) / ethanol solution, stirred at room temperature for 3 h, heated to 80 °C and stirred for 4 h, cooled to room temperature and stirred for 3 h, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (amino)).

[0025] The preparation method of the balancing agent in Example 7 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (tetramethyl orthosilicate) and a surfactant (polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer (P123)) were added to an emulsifier solution (Pickering solid particle emulsion aqueous solution) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 800℃ for 4 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.5 mol / L; the concentration of the silicon source in the mixed solution was 0.8 mol / L, and the concentration of the surfactant was 0.2 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.3 mol / L nitric acid solution) for 50 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (3-aminopropyltrimethoxysilane) / ethanol solution, stirred at room temperature for 3 h, heated to 80 °C and stirred for 4 h, cooled to room temperature and stirred for another 3 h, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (carboxyl group)).

[0026] The preparation method of the balancing agent in Example 8 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (sodium silicate) and a surfactant (betaine) were added to an emulsifier solution (polyvinyl alcohol aqueous solution) to obtain a mixed solution. The mixed solution was stirred and reacted for 4 hours, then dehydrated and calcined at 800℃ for 4 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.5 mol / L; the concentration of the silicon source in the mixed solution was 0.8 mol / L, and the concentration of the surfactant was 0.2 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.1 mol / L sulfuric acid solution) for 50 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent ((3-propyl phosphate)triethoxysilane) / ethanol solution, stirred at room temperature for 3 h, heated to 80 °C and stirred for 4 h, cooled to room temperature and stirred for another 3 h, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (phosphate group)).

[0027] The preparation method of the balancing agent in Example 9 is as follows: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source (silicon powder) and surfactants (sodium dodecylbenzenesulfonate and hexadecyltrimethyl bromide) were added to an emulsifier solution (aqueous solution of high internal phase emulsion) to obtain a mixed solution. The mixed solution was stirred and reacted for 3 hours, then dehydrated and calcined at 700℃ for 8 hours to remove the pore template and organic matter, yielding hierarchical porous SiO2. The concentration of the emulsifier solution was 0.3 mol / L; the concentration of the silicon source in the mixed solution was 1.0 mol / L, and the concentration of the surfactant was 0.1 mol / L. 2) Pre-treated multi-level porous SiO2 was added to an acid solution (0.9 mol / L hydrochloric acid solution) for activation treatment for 40 min, washed with deionized water, and dried to obtain activated SiO2; 3) Activated SiO2 was added to a silane coupling agent (vinyltriethoxysilane) / ethanol solution, stirred at room temperature for 3 hours, heated to 80°C and stirred for 4 hours, cooled to room temperature and stirred for another 3 hours, washed with deionized water and dried to obtain the equilibration agent (multi-level porous SiO2 modified with proton carrier (hydroxyl)).

[0028] The FT-IR spectrum of the hydroxylated hierarchical porous SiO2 nanospheres in Example 5 is shown in [reference needed]. Figure 2 ,from Figure 2 It can be seen that 464.8 and 1089.7 cm −1 The absorption bands at this location correspond to the Si-O stretching band and the Si-O bending band, respectively. Located at 810.1 cm⁻¹ −1 The peaks at 1635.6 and 3446.6 cm⁻¹ belong to the Si-O-Si stretching band. −1 The final absorption peak at the point is attributed to the hydroxyl (-OH) groups on the surface of SiO2, which enable the material to adsorb protons in an acidic environment; The control group did not add a balancing agent, the balancing agent in Comparative Example 1 was commercially available mesoporous SiO2, and the balancing agent in Comparative Example 2 was the hierarchical porous SiO2 prepared in Examples 1 to 3. According to the mass fraction, the lead powder, nucleating agent, short fiber, conductive carbon black, conductive polypyrrole and balancing agent in Examples 1-9 and Comparative Examples 1-3 were mixed evenly, and then deionized water and sulfuric acid solution were added and mixed evenly to obtain wet lead paste. The wet lead paste was coated on lead-calcium-tin alloy grid and cured at a temperature of 65°C and a humidity of 98% for 40 hours to obtain the lead-carbon battery positive electrode of Examples 1-9 and Comparative Examples 1-3, respectively. The positive electrode, glass fiber separator (AGM), and negative electrode of the lead-carbon battery of the control group, Examples 1-9, and Comparative Examples 1-2 were assembled into test batteries. The electrolyte was a 1.25 g / ml dilute sulfuric acid solution, and the batteries were formed and activated at 30°C. The lead-carbon batteries of Examples 1-9, the control group, Examples 1-9, and Comparative Examples 1-2 were subjected to deep cycle performance testing in a full charge-discharge (100% DOD) manner. The specific discharge mode was 0.5C 1A constant current discharge to the cutoff voltage of 1.8V, then rest for 5 min, then overcharge, and then rest for 5 min. This was one cycle of testing. The test results are shown in Table 2. The discharge curves of the lead-carbon batteries in the control group, comparative examples 1-2, and examples 1-2 are shown in the figure. Figure 3 ,from Figure 3 As can be seen, both the comparative and exemplary embodiments in the figure show a certain capacity improvement. The embodiment uses a multi-level pore structure, which allows for better electrolyte flow and improves the conversion efficiency of the active material inside the electrode. Furthermore, the proton functional groups loaded on the surface provide additional H+ during discharge. + This further enhances the conversion of active materials, resulting in a significant increase in the initial discharge capacity of the battery.

[0029] The cycle performance of the lead-carbon batteries in the control group, comparative examples 1-2, and examples 1-2 is shown in the figure. Figure 4 ,from Figure 4It can be seen that all batteries exhibited a phenomenon of capacity first increasing and then decreasing throughout the entire cycle. This is because the low energy density of the lead paste prevents the battery from maximizing the conversion of active materials during the formation process, resulting in a gradual increase in battery capacity with increasing cycle count. The figure shows that although the peak capacity of the embodiment was lower than that of the control group during cycling, the peak capacity of the embodiment clearly shifted later and increased more stably. After reaching the peak, both the control and comparative examples showed rapid capacity decay, but the embodiment maintained high stability, with capacity stabilizing for a period before slowly decaying. This further demonstrates that protonated SiO2 helps improve the cycle stability of the battery.

[0030] Table 2. Test results of lead-carbon batteries in the control group, Examples 1-9, and Comparative Examples 1-2. ; The test results of the control group, comparative examples 1-2, and examples 1-9 lead-carbon batteries are shown in Table 2. Table 2 shows that the addition of the balancer significantly improved the conversion rate of the positive electrode active material and increased the initial discharge capacity of the battery. When the battery is discharged at a high rate of 1C, the utilization rate of the positive electrode active material is mainly limited by HSO4. - and H + The movement of ions is facilitated by balancing agents with hierarchical porous structures, which can promote ion transport and also release additional H+ using functional groups. + Protons enable the battery to maintain good discharge performance even at high discharge rates. However, during cycling, other additives with unstable properties suffer structural damage, corrosion, or dissolution due to repeated charge-discharge cycles, leading to a gradual decrease in battery cycle capacity. But the high stability of SiO2 prevents it from reacting or corroding, thus allowing it to continuously and stably provide a gain effect during cycling.

[0031] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for improving the initial capacity and cycle stability of a lead-carbon battery cathode, characterized in that: The additives used in the lead-carbon battery positive electrode, which have proton buffering function, contain, by weight (100%), 80-90% lead powder, 0.1-1.0% nucleating agent, 0.1-0.5% short fiber, 0.2-0.6% conductive agent, 0.3-0.8% conductive polymer, 0.5-2.0% balancing agent, 4.0-8.0% sulfuric acid, and 8.0-12.0% deionized water. The nucleating agent is one or more of SnSO4, tetrabasic lead sulfate, and CaSO4; The balancing agent is multi-level porous SiO2 modified with a proton carrier; the proton carrier is -OH, -COOH, -NH2 or -H2PO4.

2. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 1, characterized in that: The short fibers are one or more of polypropylene fibers, polyacrylonitrile fibers, polyester fibers, or polyethylene fibers.

3. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 1, characterized in that: The conductive agent is graphene, carbon nanotubes, graphite, or conductive carbon black.

4. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 1, characterized in that: The conductive polymer is one or more of polyaniline, polypyrrole, and polythiophene.

5. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 1, characterized in that: The preparation method of the balancing agent includes the following specific steps: 1) Multi-level porous SiO2 is dispersed in ethanol and ultrasonically treated to obtain pretreated multi-level porous SiO2; 2) Pre-treated multi-level porous SiO2 is added to an acid solution for activation treatment, washed with deionized water, and dried to obtain activated SiO2; 3) Add activated SiO2 to a silane coupling agent / ethanol solution, stir and react at room temperature for 2-4 hours, heat to 40-80℃ and stir and react for 4-8 hours, cool to room temperature and continue stirring and react for 2-4 hours, wash with deionized water and dry to obtain the equilibration agent, namely, multi-level porous SiO2 modified by proton carrier.

6. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 5, characterized in that: Step 2) The acid solution is one or more of sulfuric acid, hydrochloric acid, or nitric acid.

7. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 6, characterized in that: The acid solution concentration is 0.2~0.6 mol / L.

8. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 5, characterized in that: Step 3) The silane coupling agent is one or more of 3-hydroxypropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, vinyltriethoxysilane, and (3-propyl phosphate)triethoxysilane.

9. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 5, characterized in that: The specific steps for preparing the multi-level porous SiO2 are as follows: A silicon source and a surfactant are added to an emulsifier solution to obtain a mixed solution. The mixed solution is stirred and reacted for 2-6 hours, then dehydrated and calcined at high temperature to remove the pore template and organic matter, thus obtaining multi-level porous SiO2.

10. The method for improving the initial capacity and cycle stability of the positive electrode of a lead-carbon battery according to claim 9, characterized in that: The emulsifier is polystyrene, polymethyl methacrylate, polyvinyl alcohol, high internal phase emulsion, or Pickering solid particle emulsion; the silicon source is one or more of sodium silicate, tetraethyl orthosilicate, aminosilane, silicon powder, and tetramethyl orthosilicate; the surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethyl bromide, polyoxyethylene polyoxypropylene ether triblock copolymer, polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, and betaine.

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