Lead-graphene negative electrode lead paste and preparation method thereof

Abstract

The application discloses a kind of lead-graphene negative lead paste and preparation method thereof, belong to lead-acid battery technical field;Solve the technical problem that the battery cycle service life of battery failure caused by the poor uniformity of the composition of the existing negative lead paste, negative sulphation;The lead-graphene negative lead paste and preparation method thereof of the application include: step 1, preparation lead graphene lead ingot;Step 2, preparation lead-lead oxide-graphene lead powder;The lead graphene lead ingot casted in step 1 is cut into pieces, and the pure lead lead ingot is cut into pieces, then the lead graphene lead ingot cut into pieces and the pure lead lead ingot cut into pieces are put into a ball mill, air is introduced and grinded, to obtain lead-lead oxide-graphene lead powder;Step 3, preparation lead-graphene composite negative lead paste.The battery prepared by the negative lead paste prepared by the application has a cycle life of more than 500 times, and also solves the problem of negative sulphation.

Description

Technical Field

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

[0002] The lead-acid battery was invented in 1859 by the Frenchman Plante. It mainly consists of a positive plate, a negative plate, an electrolyte, a separator, an electrolytic cell, a battery cover, and terminals. The main active component of the positive electrode is lead dioxide, and the main active component of the negative electrode is lead. The electrolyte is a sulfuric acid solution. The chemical reactions involved during discharge are as follows:

[0003] Discharge positive electrode: PbO2 + 4H + +SO4 2- +2e-=PbSO4+2H2O;

[0004] Discharge negative electrode: Pb + SO4 2- -2e - =PbSO4;

[0005] Lead-acid batteries are widely used in electric bicycles and as starting power sources for automobiles due to their good charge-discharge performance, safety, stability, and low cost. Although lead-acid batteries are widely used, their specific energy and cycle life still need improvement, especially their capacity and lifespan. These performance characteristics are generally determined by the active materials of the electrode plates, and the formulation of the lead paste affects these materials, influencing the battery's capacity, lifespan, and other performance aspects.

[0006] Currently, most lead-acid battery manufacturers use lead powder, conductive agents, binders, and fibers in their lead paste formulations. Increasing the content of conductive agents, binders, and fibers in the formulation can improve the initial performance of the battery, but it leads to a decrease in the adhesion strength of the active material and a reduction in battery life. While using graphite as the conductor in the formulation solves problems related to conversion efficiency and battery discharge capacity during formation and charge / discharge processes, these formulations fail to consider the significant density difference between graphite conductors and other formulation materials and lead powder during the paste mixing process. This results in poor mixing uniformity, and the bonding strength between the graphite conductor and the lead paste during the curing process cannot be resolved, leading to weak adhesion between the lead paste and the grid in later charge / discharge cycles. This increases electrochemical polarization, affecting subsequent charge / discharge efficiency. Furthermore, the bonding problem easily causes the lead paste to sludge and detach, further impacting battery life. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a lead-graphene negative electrode paste and its preparation method, in order to solve the technical problems of poor mixing uniformity of existing negative electrode paste components and battery failure caused by negative electrode sulfation, which reduces the battery cycle life.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] On the one hand, the present invention provides a method for preparing lead-graphene negative electrode lead paste, comprising the following steps:

[0010] Step 1: Prepare lead graphene ingots;

[0011] After graphene and sodium hydroxide are stirred and mixed evenly, they are placed together with metallic lead in an atmosphere furnace, a protective gas is introduced for protection, the temperature is raised to 600-800℃, and ultrasonic vibration is used for mixing. After mixing is completed, lead graphene ingots are cast.

[0012] Step 2: Prepare lead-lead oxide-graphene lead powder;

[0013] Cut the lead graphene ingots cast in step 1 into blocks and cut the pure lead ingots into blocks. Then, put the lead graphene ingot blocks and the pure lead ingot blocks into a ball mill, introduce air and grind them to obtain lead-lead oxide-graphene lead powder.

[0014] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0015] Take a portion of the lead-lead oxide-graphene lead powder prepared in step 2 and add it to the paste mixing machine. Then add barium sulfate, lignin, humic acid and conductive fiber. Then continue to add the remaining lead-lead oxide-graphene lead powder and dry mix. After mixing, add pure water for wet mixing and stirring. Then slowly add dilute sulfuric acid solution. After the dilute sulfuric acid solution is added, continue mixing and stirring to obtain high-performance lead-graphene composite negative electrode lead paste.

[0016] Further, in step 1, 1-50 layers of graphene with a weight ratio of 5-10% and 1-5% sodium hydroxide are stirred and mixed evenly, and then placed together with metallic lead with a weight ratio of 80-90% in an atmosphere furnace, and nitrogen or argon gas is introduced for protection.

[0017] Furthermore, in step 1, the ultrasonic oscillation mixing frequency is 20-40 Hz, and the ultrasonic oscillation mixing time is 0.5-1 h.

[0018] Furthermore, in step 2, the mass ratio of lead graphene ingot diced to pure lead ingot diced is 1:5-10.

[0019] Furthermore, in step 2, the grinding temperature of the lead graphene ingot blocks and the pure lead ingot blocks is 180-200℃, and the grinding time is 1-10h, so that the particle size of the lead-lead oxide-graphene powder prepared is 1-5μm.

[0020] Furthermore, in step 2, the lead-lead oxide-graphene lead powder is a core-shell structure lead powder with a core, a middle shell structure and an outer shell structure; the core-shell structure lead powder has lead as the core, with lead oxide wrapping around the lead core to form the middle shell structure, and graphene wrapping around the lead oxide to form the outer shell structure.

[0021] Furthermore, in step 2, the oxidation degree of the lead-lead oxide-graphene lead powder is 70-80%.

[0022] Further, in step 3, based on 100 parts of lead-lead oxide-graphene lead powder, the amount of barium sulfate added is 0.8-1.5 parts, the amount of lignin added is 0.1-0.5 parts, the amount of humic acid added is 0.1-0.5 parts, and the amount of conductive fiber added is 0.01-0.06 parts.

[0023] Further, in step 3, the dry mixing time is 5-10 min; after the dry mixing is completed, 10-12 parts of pure water with a conductivity of less than 2 μs / cm are quickly added within 1-5 min and wet-mixed for 5-10 min, and then 6-10 parts of dilute sulfuric acid solution with a density of 1.4 g / ml are slowly added dropwise within 10-15 min.

[0024] On the other hand, the present invention also provides a lead-graphene anode paste, which is prepared by the above-mentioned lead-graphene anode paste and its preparation method.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] (1) The present invention controls the mass ratio of lead graphene ingots to pure lead ingots within the range of 1:5-10, ensuring that the proportion of graphene in the lead paste formula is controlled at 0.1-1%, which can maximize the preservation of the negative electrode skeleton, enhance conductivity and significantly improve the negative electrode plate's resistance to sulfation.

[0027] (2) In this invention, the particle size of lead-lead oxide-graphene lead powder is controlled within 1-5 μm. The lead-lead oxide-graphene lead powder has a large specific surface area, and the electrode plate prepared by it has a moderate porosity, which can make the battery's electrical performance the best while ensuring the battery's cycle life.

[0028] (3) The negative electrode lead paste prepared by the preparation method of the present invention can be used to prepare a battery with a cycle life of more than 500 times, and the sulfation problem of the negative electrode is also solved.

[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0031] Figure 1 This is a comparison chart showing the cycle life of batteries prepared using the lead-graphene negative electrode paste of the present invention and batteries prepared using conventional formulas. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0033] This invention provides a lead-graphene negative electrode paste and its preparation method, comprising the following steps:

[0034] Step 1: Prepare lead graphene ingots;

[0035] 5-10% by weight of 1-50 layers of graphene and 1-5% by weight of sodium hydroxide are stirred and mixed evenly, and then placed together with 80-90% by weight of metallic lead in an atmosphere furnace. Nitrogen or argon gas is introduced for protection, and the temperature is slowly raised to 600-800℃. The mixture is stirred and ultrasonically vibrated for 0.5-1 hours. After mixing, it is cast into lead graphene ingots.

[0036] In step 1 above, controlling the weight ratio of graphene, sodium hydroxide, and metallic lead within the aforementioned range ensures the preparation of a lead-graphene alloy with graphene-modified lead. After modifying lead with graphene, the metallic lead is coated with layered graphene, thus preventing uneven mixing during the ball milling of the lead-graphene alloy into lead powder due to excessive density differences.

[0037] In step 1 above, placing graphene, sodium hydroxide, and metallic lead in an atmosphere furnace and heating it to 600-800℃ serves to rapidly dissolve the mixture alloy formed by graphene, sodium hydroxide, and metallic lead, achieving a moderate viscosity that facilitates thorough mixing. When the temperature exceeds 800℃, the energy consumption of the mixture alloy is high, and a large amount of lead slag is generated. When the temperature is below 600℃, the dissolution rate of the mixture alloy preparation process is low, the dissolution time is long, the production capacity is low, and the alloy viscosity is high, resulting in poor mixing uniformity.

[0038] In step 1 above, the frequency of ultrasonic oscillation is 20-40 Hz. Using ultrasonic oscillation and controlling its oscillation frequency within the range of 20-40 Hz can ensure that the lead-graphene alloy is mixed more uniformly.

[0039] Step 2: Prepare lead-lead oxide-graphene lead powder;

[0040] The lead graphene ingots cast in step 1 are cut into blocks, and the pure lead ingots are cut into blocks and fed into a ball mill at a mass ratio of 1:5-10. Air is introduced, and the mixture is ground at 180-200℃ for 1-10 hours to obtain lead-lead oxide-graphene powder with a particle size of 1-5μm.

[0041] It should be noted that the lead-lead oxide-graphene lead powder is a core-shell structure lead powder with a core, a middle shell structure and an outer shell structure. The core-shell structure lead powder has lead as the core, lead oxide wrapping around the lead core to form the middle shell structure, and graphene lead powder wrapping around the lead oxide to form the outer shell structure.

[0042] Compared with the prior art, the present invention designs lead-lead oxide-graphene lead powder into a core-shell structure, in which the outer shell structure and the inner shell structure can protect the core, making the core more stable; the graphene surface is modified (lead-modified graphene, because there are defects at the edges of graphene, lead combines with the edges for modification), while the shell is very active, and the core-shell structure can also combine various properties.

[0043] In step 2 above, the purpose of controlling the mass ratio of lead graphene ingots to pure lead ingots within the range of 1:5-10 is to ensure that the proportion of graphene in the lead paste formula is controlled at 0.1-1%, so as to maximize the preservation of the negative electrode framework (graphene adsorbs or embeds itself inside the lead crystals of the negative electrode active material, changing the basic properties of the negative electrode plate to form a lead graphene electrode), enhance conductivity, and significantly improve the negative electrode plate's resistance to sulfation. The alloy of lead graphene ingots and pure lead ingots within the range of 1:5-10 can meet the above requirements.

[0044] In step 2 above, the battery with the best performance is the one with the higher content of alpha lead oxide (α-PbO) in the lead powder and the oxidation degree of the lead powder is 70-80%. When the grinding temperature is higher than 200℃, the oxidation of the lead powder is too high. Since high temperature can easily cause alpha lead oxide (α-PbO) in the lead powder to beta lead oxide (β-PbO), it will affect the battery performance. At the same time, high temperature will lead to high energy consumption and high equipment maintenance costs. Therefore, the ball milling temperature is controlled at 180-200℃.

[0045] The chemical reactions that occur during ball milling are shown in the following equation:

[0046] 2Pb + O₂ → 2PbO (1)

[0047] The particle size of lead-lead oxide-graphene lead powder is controlled at 1-5μm because this lead-lead oxide-graphene lead powder has a large specific surface area, and the electrode plates prepared using it have a moderate porosity, which can make the battery's electrical performance the best while ensuring the battery's cycle life.

[0048] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0049] Based on 100 parts of lead-lead oxide-graphene lead powder, 50 parts of lead-lead oxide-graphene lead powder are added to a paste mixing machine. Then, 0.8-1.5 parts of barium sulfate, 0.1-0.5 parts of lignin, 0.1-0.5 parts of humic acid, and 0.01-0.06 parts of conductive fiber are added. The remaining 50 parts of lead-lead oxide-graphene lead powder are then added and dry-mixed for 5-10 minutes. After mixing, 10-12 parts of pure water with a conductivity of less than 2 μs / cm are quickly added within 1-5 minutes and wet-mixed for 5-10 minutes. Then, 6-10 parts of dilute sulfuric acid solution with a density of 1.4 g / ml are slowly added dropwise within 10-15 minutes. After the sulfuric acid is added, mixing and stirring are continued for 5-10 minutes to obtain a high-performance lead-graphene composite negative electrode lead paste.

[0050] In step 3 above, the function of adding 0.8-1.5 parts of barium sulfate is: barium sulfate acts as an expansion agent and a nucleating agent for lead sulfate at the negative electrode, promoting the formation of a porous small lead sulfate crystal layer on the surface of the lead electrode, inhibiting the deposition of the lead sulfate passivation layer and excessive shrinkage of the negative electrode plate during overcharging, and improving the discharge capacity of the negative electrode.

[0051] In step 3 above, 0.1-0.5 parts of lignin are added to improve the battery's low-temperature, high-rate discharge performance.

[0052] In step 3 above, the purpose of adding 0.1-0.5 parts of humic acid is to improve the battery's discharge capacity and low-temperature discharge performance.

[0053] In step 3 above, the purpose of adding 0.01-0.06 parts of conductive fiber is to increase the mechanical strength and conductivity of the plates, prevent the active material from falling off, and improve the battery cycle life.

[0054] In step 3 above, 50 parts of lead-lead oxide-graphene lead powder are added first, and then the remaining 50 parts of lead-lead oxide-graphene lead powder are added. The purpose of adding them in batches is to make the lead paste mix more evenly, to make the apparent specific gravity of the lead paste more consistent, to improve the battery packing rate, and to reduce the phenomenon of individual batteries lagging behind during the cycle.

[0055] In step 3 above, the purpose of dry mixing is to premix the lead powder and battery negative electrode additive evenly before adding pure water to wet it, so that the lead paste has plasticity and fillability.

[0056] In step 3 above, the purpose of adding 6-10 parts of dilute sulfuric acid solution with a density of 1.4 g / ml is to react the lead oxide in the lead paste with the dilute sulfuric acid to form lead sulfate, which in turn forms a tribasic lead sulfate network structure on the electrode plate during the paste preparation and curing process, thereby improving the bonding force and mechanical strength between the electrode plate and the grid, and promoting the electrochemical activity of the electrode after battery formation.

[0057] Compared with existing technologies, this invention solves the problem of poor uniformity in mixing lead powder with carbon materials such as graphite and graphene; it improves the conductivity of negative electrode lead paste and enhances the bonding ability between the grid and the lead paste, solves the battery failure caused by negative electrode sulfation, and improves the battery cycle life.

[0058] This invention also provides a lead-graphene anode paste, prepared using the aforementioned method. A battery made from this lead-graphene anode paste exhibits a cycle life exceeding 500 cycles (e.g., ...). Figure 1 (As shown), and it also solved the problem of sulfation of the negative electrode.

[0059] Example 1

[0060] Step 1: Prepare lead graphene ingots;

[0061] 6% by weight of 5-10 layers of graphene and 2% by weight of sodium hydroxide are stirred and mixed evenly, and then placed together with 81% by weight of metallic lead in an atmosphere furnace. Nitrogen or argon gas is introduced for protection, and the temperature is slowly raised to 610°C. The mixture is stirred and ultrasonically vibrated for 0.6 hours. After mixing, it is cast into lead graphene ingots.

[0062] Step 2: Prepare lead-lead oxide-graphene lead powder;

[0063] The cast lead graphene ingots were cut into blocks and pure lead ingots were cut into blocks. The blocks were then fed into a ball mill at a mass ratio of 1:5. Air was introduced, and the mixture was ground at 180°C for 2 hours to obtain lead-lead oxide-graphene powder with an average particle size of 2.18 μm.

[0064] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0065] Take 50 parts of the lead-lead oxide-graphene lead powder with a particle size of 2.18μm and add it to the paste mixing machine. Add 1 part of barium sulfate, 0.2 parts of lignin, 0.1 parts of humic acid, and 0.02 parts of conductive fiber. Then add the remaining 50 parts of lead-lead oxide-graphene lead powder and dry mix for 10 minutes. After mixing, quickly add 10 parts of pure water with a conductivity of less than 2μs / cm and wet mix for 5 minutes. Then slowly add 6 parts of dilute sulfuric acid solution with a density of 1.4g / ml within 10 minutes. After the sulfuric acid is added, continue mixing and stirring for 5 minutes to obtain a high-performance lead-graphene composite negative electrode lead paste.

[0066] The battery assembled with the negative electrode plate prepared by the method of this embodiment and a conventional positive electrode plate has a cycle life of 534 cycles.

[0067] Example 2

[0068] Step 1: Prepare lead graphene ingots;

[0069] 8% by weight of 5-10 layers of graphene and 3% by weight of sodium hydroxide are stirred and mixed evenly, and then placed together with 85% by weight of metallic lead in an atmosphere furnace. Nitrogen or argon gas is introduced for protection, and the temperature is slowly raised to 700°C. The mixture is stirred and ultrasonically vibrated for 0.7 hours. After mixing, it is cast into lead graphene ingots.

[0070] Step 2: Prepare lead-lead oxide-graphene lead powder;

[0071] The cast lead graphene ingots were cut into blocks and pure lead ingots were cut into blocks. The blocks were then fed into a ball mill at a mass ratio of 1:8. Air was introduced, and the mixture was ground at 190°C for 5 hours to obtain lead-lead oxide-graphene powder with an average particle size of 4.2 μm.

[0072] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0073] Take 50 parts of the lead-lead oxide-graphene lead powder with a particle size of 4.2μm and add it to the paste mixing machine. Add 1.2 parts of barium sulfate, 0.3 parts of lignin, 0.3 parts of humic acid, and 0.04 parts of conductive fiber. Then add the remaining 50 parts of lead-lead oxide-graphene lead powder and dry mix for 10 minutes. After mixing, quickly add 11 parts of pure water with a conductivity of less than 2μs / cm and wet mix for 7 minutes. Then slowly add 8 parts of dilute sulfuric acid solution with a density of 1.4g / ml over 13 minutes. After the sulfuric acid is added, continue mixing and stirring for 8 minutes to obtain a high-performance lead-graphene composite negative electrode lead paste.

[0074] The battery assembled with the negative electrode plate prepared by the method of this embodiment and a conventional positive electrode plate has a cycle life of 540 cycles.

[0075] Example 3

[0076] Step 1: Prepare lead graphene ingots;

[0077] 9% by weight of 5-10 layers of graphene and 5% by weight of sodium hydroxide are stirred and mixed evenly, and then placed together with 90% by weight of metallic lead in an atmosphere furnace. Nitrogen or argon gas is introduced for protection, and the temperature is slowly raised to 800°C. The mixture is stirred and ultrasonically vibrated for 0.9 hours. After mixing, it is cast into lead graphene ingots.

[0078] Step 2: Prepare lead-lead oxide-graphene lead powder;

[0079] The cast lead graphene ingots were cut into blocks and pure lead ingots were cut into blocks. The blocks were then fed into a ball mill at a mass ratio of 1:9. Air was introduced, and the mixture was ground at 200℃ for 9 hours to obtain lead-lead oxide-graphene powder with an average particle size of 4.8 μm.

[0080] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0081] Take 50 parts of the lead-lead oxide-graphene lead powder with a particle size of 4.8μm and add it to the paste mixing machine. Add 1.4 parts of barium sulfate, 0.4 parts of lignin, 0.5 parts of humic acid, and 0.06 parts of conductive fiber. Then add the remaining 50 parts of lead-lead oxide-graphene lead powder and dry mix for 10 minutes. After mixing, quickly add 12 parts of pure water with a conductivity of less than 2μs / cm and wet mix for 10 minutes. Then slowly add 10 parts of dilute sulfuric acid solution with a density of 1.4g / ml over 15 minutes. After the sulfuric acid is added, continue mixing and stirring for 9 minutes to obtain a high-performance lead-graphene composite negative electrode lead paste.

[0082] The battery assembled with the negative electrode plate prepared by the method of this embodiment and a conventional positive electrode plate has a cycle life of 530 cycles.

[0083] Comparative Example 1

[0084] Step 1: Prepare lead-lead oxide powder;

[0085] Lead ingots were fed into a ball mill, air was introduced, and the mixture was ground at 200°C for 9 hours to obtain lead-lead oxide powder with an average particle size of 2.7 μm.

[0086] Step 3: Prepare lead-graphene composite negative electrode lead paste;

[0087] Take 50 parts of lead-lead oxide with a particle size of 2.7μm and add them to the paste mixing machine. Add 1.4 parts of barium sulfate, 0.2 parts of lignin, 0.1 parts of humic acid, 0.1 parts of conductive fiber, and 0.3 parts of carbon black. Then add the remaining 50 parts of lead-lead oxide powder and dry mix for 10 minutes. After mixing, quickly add 12 parts of pure water with a conductivity of less than 2μs / cm and wet mix for 10 minutes. Then slowly add 10 parts of dilute sulfuric acid solution with a density of 1.4g / ml over 15 minutes. After the sulfuric acid is added, continue mixing and stirring for 10 minutes to obtain a high-performance lead-carbon black composite negative electrode paste.

[0088] The battery assembled with the negative electrode plate prepared by the method of this embodiment and a conventional positive electrode plate has a cycle life of 244 cycles.

[0089] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing lead-graphene negative electrode lead paste, characterized in that, Includes the following steps: Step 1: Prepare lead graphene ingots; After graphene and sodium hydroxide are stirred and mixed evenly, they are placed together with metallic lead in an atmosphere furnace, a protective gas is introduced for protection, the temperature is raised to 600-800℃, and ultrasonic vibration is used for mixing. After mixing is completed, lead graphene ingots are cast. Step 2: Prepare lead-lead oxide-graphene lead powder; The lead graphene ingots cast in step 1 are cut into blocks, and the pure lead ingots are also cut into blocks. Then, the lead graphene ingot blocks and the pure lead ingot blocks are put into a ball mill, air is introduced and they are ground to obtain lead-lead oxide-graphene lead powder. In step 2, the mass ratio of lead graphene ingot diced to pure lead ingot diced is 1:5-10. Step 3: Prepare lead-graphene composite negative electrode lead paste; Take a portion of the lead-lead oxide-graphene lead powder prepared in step 2 and add it to the paste mixing machine. Then add barium sulfate, lignin, humic acid and conductive fiber. Then continue to add the remaining lead-lead oxide-graphene lead powder and dry mix. After mixing, add pure water to wet mix and stir. Then slowly add dilute sulfuric acid solution. After the dilute sulfuric acid solution is added, continue to mix and stir to obtain high-performance lead-graphene composite negative electrode lead paste. The lead-lead oxide-graphene lead powder is a core-shell structure lead powder with a core, a middle shell structure and an outer shell structure. The core-shell structure lead powder has lead as the core, lead oxide wrapping around the lead core to form the middle shell structure, and graphene lead powder wrapping around the lead oxide to form the outer shell structure; and the oxidation degree of the lead powder is 70-80%.

2. The method for preparing lead-graphene negative electrode lead paste according to claim 1, characterized in that, In step 1, 1-50 layers of graphene (5-10% by weight) and sodium hydroxide (1-5% by weight) are stirred and mixed evenly, and then placed together with metallic lead (80-90% by weight) in an atmosphere furnace, and nitrogen or argon gas is introduced for protection.

3. The method for preparing lead-graphene negative electrode lead paste according to claim 2, characterized in that, In step 1, the frequency of the ultrasonic oscillation mixing is 20-40 Hz, and the ultrasonic oscillation mixing time is 0.5-1 h.

4. The method for preparing lead-graphene negative electrode lead paste according to claim 3, characterized in that, In step 2, the grinding temperature of the lead graphene ingot blocks and the pure lead ingot blocks is 180-200℃, the grinding time is 1-10h, and the particle size of the lead-lead oxide-graphene powder prepared is 1-5μm.

5. The method for preparing lead-graphene negative electrode lead paste according to claim 4, characterized in that, In step 2, the oxidation degree of the lead-lead oxide-graphene lead powder is 70-80%.

6. The method for preparing lead-graphene negative electrode lead paste according to claim 5, characterized in that, In step 2, the lead-lead oxide-graphene lead powder is a core-shell structure lead powder with a core, a middle shell structure and an outer shell structure; the core-shell structure lead powder has lead as the core, lead oxide wrapping around the lead core to form the middle shell structure, and graphene wrapping around the lead oxide to form the outer shell structure.

7. The method for preparing lead-graphene negative electrode lead paste according to claim 1, characterized in that, In step 3, based on 100 parts of lead-lead oxide-graphene lead powder, the amount of barium sulfate added is 0.8-1.5 parts, the amount of lignin added is 0.1-0.5 parts, the amount of humic acid added is 0.1-0.5 parts, and the amount of conductive fiber added is 0.01-0.06 parts.

8. The method for preparing lead-graphene negative electrode lead paste according to claim 7, characterized in that, In step 3, based on 100 parts of lead-lead oxide-graphene lead powder, the dry mixing time is 5-10 min; after the dry mixing is completed, 10-12 parts of pure water with a conductivity of less than 2 μs / cm are quickly added within 1-5 min and the mixture is stirred for 5-10 min, and then 6-10 parts of dilute sulfuric acid solution with a density of 1.4 g / ml are slowly added dropwise within 10-15 min.

9. A lead-graphene negative electrode paste, characterized in that, It is prepared using the lead-graphene negative electrode lead paste preparation method according to any one of claims 1 to 8.

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