Lead-carbon battery negative electrode lead paste, negative electrode material and lead-carbon battery

Abstract

The invention belongs to the technical field of lead-acid storage batteries, and particularly relates to lead-carbon battery negative electrode lead paste containing chromium sulfide quantum dot doped single-walled carbon nanotubes, a negative electrode material and a lead-carbon battery. The lead-carbon battery negative electrode lead paste comprises a first mixed component and dilute sulphuric acid, the first mixed component comprises lead powder and a functional dispersion liquid, and the functional dispersion liquid comprises deionized water and chromium sulfide quantum dot doped single-walled carbon nanotubes. The chromium sulfide quantum dot doped single-walled carbon nanotube is added into the lead paste as a functional component, and after the single-walled carbon nanotube is subjected to chromium sulfide quantum dot doping functionalization treatment, the hydrogen evolution reaction can be reduced on the premise of delaying the sulfation of the negative electrode, and the service life of the lead-carbon battery is remarkably prolonged.

Description

Technical Field

[0001] This invention belongs to the field of lead-acid battery technology, and particularly relates to a lead-carbon battery negative electrode paste containing chromium sulfide quantum dot-doped single-walled carbon nanotubes, a negative electrode material, and a lead-carbon battery. Background Technology

[0002] Lead-carbon batteries are widely used in communications, power, transportation, and railway fields due to their advantages such as readily available raw materials, low cost, no memory effect, and wide operating temperature range. However, early capacity loss (PCL) occurs during use, affecting battery performance. Therefore, to improve battery performance, various additives are added to the positive and negative electrodes, such as single-walled carbon nanotubes, organic expanders, conductive agents, and stabilizers. Although these additives constitute a small proportion of the lead paste, they play an important role.

[0003] Irreversible sulfation of the negative electrode is the primary cause of lead-carbon battery failure under energy storage conditions. The dense, non-conductive PbSO4 layer on the surface of the negative electrode restricts the electrochemical reaction between Pb and PbSO4, ultimately leading to a decrease in the battery's energy storage life. Therefore, researchers have implemented various measures to suppress irreversible sulfation of the negative electrode. Existing research has found that adding single-walled carbon nanotubes to the negative electrode is a promising approach to mitigating sulfation, and carbon additives have a significant impact on the energy storage cycle performance of the negative electrode.

[0004] During energy storage mode operation, carbon additives in lead-carbon batteries can delay negative electrode sulfation by hindering the Ostwald rinsing process. Unfortunately, while adding trace amounts of single-walled carbon nanotubes (SUVs) to NAMs can alleviate negative electrode sulfation, optimizing the LAB's 50% SoC lifespan with carbon additives has a negative consequence: a reduced hydrogen evolution overpotential, exacerbating the hydrogen evolution reaction (HER) and leading to battery water loss. This limits the beneficial effects that SUVs should provide. SUVs exacerbate HER by lowering the HER overpotential, ultimately causing the lead-carbon battery to dry out and fail. The increased HER due to the addition of SUVs to the negative electrode may be due to the high specific surface area of ​​carbon itself, which expands the specific surface area of ​​the negative electrode (HER is linearly correlated with carbon surface area).

[0005] Therefore, any attempt to suppress hydrogen evolution by reducing the active surface area is likely to backfire, as the capacitance mechanism of single-walled carbon nanotubes is positively correlated with the active surface area. To address this issue, researchers have made numerous efforts over the past few years. Comparing published findings, methods such as controlling the amount of single-walled carbon nanotubes added, modifying single-walled carbon nanotubes, and incorporating hydrogen evolution inhibitors into single-walled carbon nanotubes have been identified as effective methods for suppressing hydrogen evolution and extending the energy storage mode life of lead-carbon batteries.

[0006] However, the single-walled carbon nanotubes prepared by these new technologies are not ideal for solving the problem of premature failure of lead-carbon batteries due to water loss, and they are also very expensive.

[0007] Therefore, it is necessary to develop a new single-walled carbon nanotube additive for the negative electrode to effectively improve the performance degradation of lead-carbon batteries caused by water loss in energy storage cycle mode, thereby improving battery life. Summary of the Invention

[0008] This application addresses the performance degradation problem of lead-carbon batteries due to water loss during energy storage cycling. It proposes doping single-walled carbon nanotubes with certain metals. If the work function of the metal (such as Pb particles) is greater than the electron affinity of carbon, contact between the two materials will cause electrons to flow from carbon to the metal, thus aligning their Fermi levels. The remaining positive charge in the single-walled carbon nanotubes will alter the space charge region, potentially increasing the hydrogen evolution overpotential and reducing the hydrogen evolution reaction. More specifically, by adding chromium sulfide quantum dot-doped single-walled carbon nanotubes as a functional component to lead paste, the chromium sulfide quantum doping functionalization of the single-walled carbon nanotubes can reduce the hydrogen evolution reaction while delaying sulfation of the negative electrode, significantly improving the lifespan of lead-carbon batteries.

[0009] The specific technical solution is as follows: The present invention provides a lead paste for the negative electrode of a lead-carbon battery, comprising a first mixed component and dilute sulfuric acid. The first mixed component comprises lead powder and a functional dispersion, wherein the functional dispersion contains deionized water and chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0010] As a lead-carbon battery negative electrode paste provided by the present invention, the content of functional dispersion in the first mixed component is 0.06~0.12wt%.

[0011] As a lead-carbon battery negative electrode paste provided by the present invention, the mass ratio of deionized water to chromium sulfide quantum dot-doped single-walled carbon nanotubes in the functional dispersion is (99.85~99.9):(0.1~0.15).

[0012] As a lead-carbon battery negative electrode paste provided by the present invention, the first mixed component further includes polypropylene short fibers, barium sulfate, humic acid and lignin.

[0013] As a lead-carbon battery negative electrode paste provided by the present invention, the contents of each component in the first mixed component are as follows: 0.05~0.08wt% polypropylene short fiber, 0.5~0.8wt% barium sulfate, 0.6~0.9wt% humic acid, 0.19~0.29wt% lignin, and the balance is lead powder.

[0014] As a lead paste for the negative electrode of a lead-carbon battery provided by the present invention, the mass ratio of dilute sulfuric acid to lead powder is (0.040~0.045):1, and the density of the dilute sulfuric acid is 1.40~1.43 g / cm³. 3 .

[0015] As a lead paste for the negative electrode of a lead-carbon battery provided by the present invention, the method for preparing the chromium sulfide quantum dot-doped single-walled carbon nanotubes is as follows: Single-walled carbon nanotubes were added to an aqueous solution of thioacetamide and a mixture of chromium nitrate and N,N-dimethylformamide. The mixture was stirred at 20–25°C for 1–2 hours. After stirring, the mixture was transferred to a reaction vessel at 90–100°C and kept at that temperature for 10–12 hours to obtain the reaction solution. The solution after the reaction was subjected to sonication and centrifugation in sequence, repeated several times, and the solid precipitate was retained. The solid precipitate was dried to obtain the chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0016] As a lead-carbon battery negative electrode paste provided by the present invention, the mass ratio of single-walled carbon nanotubes, thioacetamide and chromium nitrate is (0.08~0.1):(0.12~0.15):(0.45~0.48).

[0017] The present invention also provides a lead-carbon battery negative electrode, comprising a negative electrode grid and a negative electrode lead paste as described in any of the above claims, wherein the negative electrode lead paste is coated on the surface of the negative electrode grid.

[0018] The present invention also provides a lead-carbon battery, comprising a positive electrode, a negative electrode and an electrolyte, wherein the negative electrode is a lead-carbon battery negative electrode as described in any of the above claims.

[0019] The beneficial effects of this invention are as follows: The present invention provides a lead paste for the negative electrode of a lead-carbon battery. By adding chromium sulfide quantum dot-doped single-walled carbon nanotubes as a functional component to the lead paste, the single-walled carbon nanotubes, after being functionalized by chromium sulfide quantum dot doping, can reduce the hydrogen evolution reaction while delaying the sulfation of the negative electrode, thus significantly improving the life of the lead-carbon battery. Attached Figure Description

[0020] Fig. 1These are the results of the linear current-voltage (LSV) electrochemical performance tests for negative plates #1 to #5. Fig. 2 These are the 20-hour capacity test results of batteries assembled from negative plates #1 to #5. Fig. 3 The results are the 50% SoC cycle test and weight change of the negative plates from #1 to #5 assembled into the battery. Detailed Implementation

[0021] In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments. However, those skilled in the art will understand that the invention can be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. Unless the context otherwise requires, throughout the specification and appended claims, the word "comprising" should be interpreted in an open-ended, inclusive sense, i.e., as "including but not limited to".

[0022] The present invention provides a lead paste for the negative electrode of a lead-carbon battery, comprising a first mixed component and dilute sulfuric acid. The first mixed component comprises lead powder and a functional dispersion, wherein the functional dispersion contains deionized water and chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0023] Lead-carbon batteries are energy storage devices that combine supercapacitors and lead-acid batteries in parallel. The activated carbon material has a high specific surface area in the negative electrode of a traditional lead-acid battery. The activated carbon material includes activated carbon, carbon nanotubes, and graphene.

[0024] The first mixed component refers to the mixture of at least two different components. In the lead-carbon battery negative electrode paste provided by the present invention, lead powder is one of the components with a relatively high content.

[0025] As a lead-carbon battery negative electrode paste provided by the present invention, the content of functional dispersion in the first mixed component is 0.06~0.12wt%.

[0026] As a lead-carbon battery negative electrode paste provided by the present invention, the mass ratio of deionized water to chromium sulfide quantum dot-doped single-walled carbon nanotubes in the functional dispersion is (99.85~99.9):(0.1~0.15).

[0027] As a lead-carbon battery negative electrode paste provided by the present invention, the first mixed component further includes polypropylene short fibers, barium sulfate, humic acid and lignin.

[0028] As a lead-carbon battery negative electrode paste provided by the present invention, the contents of each component in the first mixed component are as follows: 0.05~0.08wt% polypropylene short fiber, 0.5~0.8wt% barium sulfate, 0.6~0.9wt% humic acid, 0.19~0.29wt% lignin, and the balance is lead powder.

[0029] As a lead paste for the negative electrode of a lead-carbon battery provided by the present invention, the mass ratio of dilute sulfuric acid to lead powder is (0.040~0.045):1, and the density of the dilute sulfuric acid is 1.40~1.43 g / cm³. 3 .

[0030] As a lead-carbon battery negative electrode paste provided by the present invention, a method for preparing the chromium sulfide quantum dot-doped single-walled carbon nanotubes is as follows: Single-walled carbon nanotubes were added to an aqueous solution of thioacetamide and a mixture of chromium nitrate and N,N-dimethylformamide. The mixture was stirred at 20–25°C for 1–2 hours. After stirring, the mixture was transferred to a reaction vessel at 90–100°C and kept at that temperature for 10–12 hours to obtain the reaction solution. The solution after the reaction was subjected to sonication and centrifugation in sequence, repeated several times, and the solid precipitate was retained. The solid precipitate was dried to obtain the chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0031] In the above method of this application, thioacetamide acts as the sulfur ion S 2- The source of chromium nitrate is its hydrolysis reaction in aqueous solution, producing hydrogen sulfide (H2S) and acetamide; the chromium ion in chromium nitrate is trivalent (Cr). 3+ The hydrothermal method controls the reaction temperature to achieve the desired Cr content on the surface of carbon materials. 3+ The adsorption of hydrogen sulfide generated by the hydrolysis of thioacetamide is a weak acid, providing sulfur for the reaction. 2- Through interactions such as electrostatic forces, hydrogen bonding forces, and van der Waals forces, it interacts with Cr adsorbed on the surface of carbon materials. 3 ⁺ They combine to form chromium sulfide precipitate, while acetamide and nitric acid are also produced. Cr2S3 is insoluble in water, CH3 is a gas, and CONH2 and HNO3 are soluble in water.

[0032] As a lead-carbon battery negative electrode paste provided by the present invention, the mass ratio of single-walled carbon nanotubes, thioacetamide and chromium nitrate is (0.08~0.1):(0.12~0.15):(0.45~0.48).

[0033] As a lead paste for the negative electrode of a lead-carbon battery provided by the present invention, another method for preparing the chromium sulfide quantum dot-doped single-walled carbon nanotubes is as follows: Single-walled carbon nanotubes were added to an aqueous solution of sodium sulfide, chromium acetate, and DMF solvent, and stirred at 20–25°C for 1–2 h. After stirring, the mixture was transferred to a reaction vessel at 70–90°C and kept at that temperature for 18–22 h to obtain the reaction solution. The solution after the reaction was subjected to sonication and centrifugation in sequence, repeated several times, and the solid precipitate was retained. The solid precipitate was dried to obtain the chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0034] Based on the above-mentioned lead-carbon battery negative electrode paste, the present invention also provides a lead-carbon battery negative electrode, including a negative electrode grid and a negative electrode paste, wherein the negative electrode paste is coated on the surface of the negative electrode grid.

[0035] Based on the above-mentioned lead-carbon battery negative electrode, the present invention also provides a lead-carbon battery, including a positive electrode, a negative electrode and an electrolyte.

[0036] Preparation Example 1 Single-walled carbon nanotubes were added to an aqueous solution of thioacetamide and a mixture of chromium nitrate and N,N-dimethylformamide. The mixture was stirred at 25°C for 2 hours and then transferred to a reaction vessel at 90°C for 12 hours to obtain the reaction solution. The solution after the reaction was subjected to sonication and centrifugation in sequence, repeated three times, and the solid precipitate was retained. The solid precipitate was dried to obtain the chromium sulfide quantum dot-doped single-walled carbon nanotubes.

[0037] The composition includes 0.08 g of single-walled carbon nanotubes, 0.12 g of thioacetamide dissolved in 1 L of water to form an aqueous solution of thioacetamide, 0.45 g of chromium nitrate, and 1 L of N,N-dimethylformamide.

[0038] Chromium sulfide quantum dot-doped single-walled carbon nanotubes were dispersed in 1 L of deionized water to obtain a functional dispersion in which the content of chromium sulfide quantum dot-doped single-walled carbon nanotubes was 0.12 wt%.

[0039] Example 1 Lead powder, polypropylene short fibers, barium sulfate, humic acid, lignin, and a functional dispersion were mixed and stirred until homogeneous to obtain the first mixed component. Then, a mixture with a density of 1.42 g / cm³ was added. 3 Dilute sulfuric acid is added and stirred until homogeneous to obtain acidic lead paste.

[0040] In the first mixed component, the content of functional dispersion is 0.06wt%, the content of polypropylene short fiber is 0.05wt%, the content of barium sulfate is 0.5wt%, the content of humic acid is 0.6wt%, the content of lignin is 0.19wt%, and the balance is lead powder; the mass ratio of dilute sulfuric acid to lead powder is 0.04:1, and the mass of lead powder is 1kg.

[0041] Example 2 Lead powder, polypropylene short fibers, barium sulfate, humic acid, lignin, and a functional dispersion were mixed and stirred until homogeneous to obtain the first mixed component. Then, a mixture with a density of 1.42 g / cm³ was added. 3 Dilute sulfuric acid is added and stirred until homogeneous to obtain acidic lead paste.

[0042] In the first mixed component, the content of functional dispersion is 0.08wt%, the content of polypropylene short fiber is 0.05wt%, the content of barium sulfate is 0.5wt%, the content of humic acid is 0.6wt%, the content of lignin is 0.19wt%, and the balance is lead powder; the mass ratio of dilute sulfuric acid to lead powder is 0.04:1, and the mass of lead powder is 1kg.

[0043] Example 3 Lead powder, polypropylene short fibers, barium sulfate, humic acid, lignin, and a functional dispersion were mixed and stirred until homogeneous to obtain the first mixed component. Then, a mixture with a density of 1.42 g / cm³ was added. 3 Dilute sulfuric acid is added and stirred until homogeneous to obtain acidic lead paste.

[0044] In the first mixed component, the content of functional dispersion is 0.1wt%, the content of polypropylene short fiber is 0.05wt%, the content of barium sulfate is 0.5wt%, the content of humic acid is 0.6wt%, the content of lignin is 0.19wt%, and the balance is lead powder; the mass ratio of dilute sulfuric acid to lead powder is 0.04:1, and the mass of lead powder is 1kg.

[0045] Example 4 Lead powder, polypropylene short fibers, barium sulfate, humic acid, lignin, and a functional dispersion were mixed and stirred until homogeneous to obtain the first mixed component. Then, a mixture with a density of 1.42 g / cm³ was added. 3 Dilute sulfuric acid is added and stirred until homogeneous to obtain acidic lead paste.

[0046] In the first mixed component, the content of functional dispersion is 0.12wt%, the content of polypropylene short fiber is 0.05wt%, the content of barium sulfate is 0.5wt%, the content of humic acid is 0.6wt%, the content of lignin is 0.19wt%, and the balance is lead powder; the mass ratio of dilute sulfuric acid to lead powder is 0.04:1, and the mass of lead powder is 1kg.

[0047] Comparative Example 1 Lead powder, polypropylene short fibers, barium sulfate, humic acid, and lignin were mixed and stirred evenly to obtain the first mixed component. Then, a mixture with a density of 1.42 g / cm³ was added. 3 Dilute sulfuric acid is added and stirred until homogeneous to obtain acidic lead paste.

[0048] In the first mixed component, the content of polypropylene short fiber is 0.05wt%, the content of barium sulfate is 0.5wt%, the content of humic acid is 0.6wt%, the content of lignin is 0.19wt%, and the balance is lead powder; the mass ratio of dilute sulfuric acid to lead powder is 0.04:1, and the mass of lead powder is 1kg.

[0049] Application Example 1 The acidic lead paste from Examples 1 to 4 and Comparative Example 1 was coated onto the grid of the negative electrode plate of a lead-carbon battery to obtain negative electrode plates, which were marked as 1# to 5# respectively.

[0050] And assemble the negative plates from #1 to #5 into a 2V 0.7Ah lead-carbon battery.

[0051] Performance testing includes linear current-voltage characteristic testing, 20hr capacity testing, and 50% SoC cycle testing.

[0052] (1) Linear current-voltage characteristic test: a. The linear current-voltage (LSV) electrochemical performance test of the negative electrode plate was carried out in H2SO4 (1.30 g cm−3) solution; b. The test uses a three-electrode system, with the negative electrode plate as the working electrode, the platinum sheet as the counter electrode, and the Hg / Hg2SO4 electrode as the reference electrode.

[0053] c. The tests were conducted on a Metrohm Multi Autolab / M204 electrochemical workstation equipped with an amplifier.

[0054] d. The scanning potential range for the linear current-voltage characteristic (LSV) test is 0.0 to -1.7 V (vs. Hg / Hg2SO4), the scanning rate is 5 mV·s-1, and the current / voltage sensitivity is set to 1×10-2.

[0055] (2) 20hr capacity test: a. After the battery is fully charged, discharge it at a constant current of 0.05 times its capacity (0.05 C) to the cutoff voltage of 1.75 V for 10 charge-discharge cycles. b. Record the charge-discharge curves of the 10th cycle to evaluate the capacity of the simulated battery.

[0056] (3) 50% SoC Cyclic Test: a. Before the 50% SoC cycle test, the battery is discharged to 50% SoC (i.e., 50% SoC) at a current of 1 C (1 capacity). b. Test the battery's 50% SoC performance using a simulated micro-hybrid drive mode. Simulate 1C charging for 30 seconds, resting for 10 seconds, 1C discharging for 30 seconds, resting for 10 seconds, and repeating this cycle. c. Terminate the cycle test when the discharge voltage (Vdischarge) drops to 1.6 V or the charging voltage (Vcharge) rises to 2.83 V, and record 50% of the SoC cycle count. d. During the 50% SoC cycle, the battery is weighed and the weight loss is recorded every 3000 cycles.

[0057] Performance tests were conducted on negative plates #1 to #5. The test results are shown below. Figs. 1 to 3 .

[0058] like Fig. 1 The figure shows the linear current-voltage (LSV) electrochemical performance test results of negative plates #1 to #5. The hydrogen evolution rate of the negative plate under overcharge conditions was evaluated by using the LSV current density. The comparison shows that the addition of chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material can reduce the hydrogen evolution rate by lowering the overpotential of the hydrogen evolution reaction of the negative plate. The current of the negative plate at -1.40 V decreases with the increase of chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material, which indicates that the chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material can alleviate the hydrogen evolution reaction of the negative plate.

[0059] like Fig. 2 The image shows the 20-hour capacity test results for a 2V 0.7Ah lead-carbon battery composed of negative plates #1 to #5. The results indicate that adding chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material to the negative plates increases the discharge capacity by at least 15.56%, significantly improving the battery's discharge capacity. The discharge capacity of the battery increases with the increase in the amount of chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material added.

[0060] like Fig. 3 The image shows the 50% SoC cycle test and weight change results for a 2V 0.7Ah lead-carbon battery composed of negative plates #1 to #5. The results indicate that the addition of chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material has a positive impact on the cycle life of the lead-carbon battery, increasing it by at least 1.36 times and improving battery life. Furthermore, with the increase in the amount of chromium sulfide quantum dot-doped single-walled carbon nanotube composite functionalized material added, the water loss in the battery gradually slows down, effectively alleviating the premature failure problem caused by water loss in lead-carbon batteries.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A lead paste for the negative electrode of a lead-carbon battery, characterized in that, It includes a first mixed component and dilute sulfuric acid, the first mixed component comprising lead powder and a functional dispersion, the functional dispersion containing deionized water and chromium sulfide quantum dot-doped single-walled carbon nanotubes.

2. The lead paste for the negative electrode of a lead-carbon battery according to claim 1, characterized in that, The content of the functional dispersion in the first mixed component is 0.06~0.12wt%.

3. The lead paste for the negative electrode of a lead-carbon battery according to claim 1, characterized in that, In the functional dispersion, the mass ratio of deionized water to chromium sulfide quantum dot-doped single-walled carbon nanotubes is (99.85~99.9):(0.1~0.15).

4. The lead paste for the negative electrode of a lead-carbon battery according to claim 1, characterized in that, The first mixed component also includes polypropylene short fibers, barium sulfate, humic acid and lignin.

5. The lead paste for the negative electrode of a lead-carbon battery according to claim 3, characterized in that, The contents of each component in the first mixed component are as follows: 0.05~0.08wt% polypropylene short fiber, 0.5~0.8wt% barium sulfate, 0.6~0.9wt% humic acid, 0.19~0.29wt% lignin, and the balance is lead powder.

6. The lead paste for the negative electrode of a lead-carbon battery according to claim 1, characterized in that, The mass ratio of the dilute sulfuric acid to lead powder is (0.040~0.045):1, and the density of the dilute sulfuric acid is 1.40~1.43 g / cm³. 3 .

7. The lead paste for the negative electrode of a lead-carbon battery according to claim 1, characterized in that, The preparation method of the chromium sulfide quantum dot-doped single-walled carbon nanotubes is as follows: Single-walled carbon nanotubes were added to an aqueous solution of thioacetamide and a mixture of chromium nitrate and N,N-dimethylformamide. The mixture was stirred at 20–25°C for 1–2 hours. After stirring, the mixture was transferred to a reaction vessel at 90–100°C and kept at that temperature for 10–12 hours to obtain the reaction solution. The solution after the reaction was subjected to sonication and centrifugation in sequence, repeated several times, and the solid precipitate was retained. The solid precipitate was dried to obtain the chromium sulfide quantum dot-doped single-walled carbon nanotubes.

8. The lead paste for the negative electrode of a lead-carbon battery according to claim 7, characterized in that, The mass ratio of the single-walled carbon nanotubes, thioacetamide, and chromium nitrate is (0.08–0.1):(0.12–0.15):(0.45–0.48).

9. A negative electrode for a lead-carbon battery, characterized in that, It includes a negative electrode grid and a negative electrode lead paste as described in any one of claims 1 to 8, wherein the negative electrode lead paste is coated on the surface of the negative electrode grid.

10. A lead-carbon battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode is a lead-carbon battery negative electrode as described in claim 9.

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