Negative electrode lead paste of energy storage lead-acid battery and preparation process of negative electrode lead paste

Abstract

The invention relates to the technical field of lead-acid batteries, in particular to energy storage lead-acid battery negative electrode lead paste which comprises the following components in parts by weight: 100 parts of lead powder, 10-15 parts of deionized water, 8-12 parts of sulfuric acid and 2-5 parts of a composite conductive network agent. The preparation process of the negative electrode lead paste of the energy storage lead-acid battery comprises the following steps: S1, vacuum pore forming; according to the invention, a composite conductive network agent and a carbon material are adopted to construct a dual composite conductive network, a stepped expanding agent is cooperated to construct a multi-stage pore structure, and bismuth oxide quantum dot modified graphitized carbon fiber is introduced as a low-temperature reinforcing agent to achieve a synergistic effect with a three-dimensional conductive network of a fiber carrier; the conductivity and the low-temperature capacity retention rate are obviously improved; and meanwhile, manufacturing is optimized through a four-order synergistic process of vacuum pore-forming, argon ball milling, ultrasonic activation and temperature-controlled kneading, so that the rate capability, the structural stability, the low-temperature capacity retention ratio and the cycle life of the lead-acid battery are synergistically improved finally.

Description

Technical Field

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

[0002] Lead-acid batteries are widely used in energy storage due to their low cost and high safety. With the rapid development of lead-acid battery technology and the continuous emergence of new materials and processes, higher requirements are being placed on the water loss and overcharge resistance of lead-acid batteries.

[0003] However, traditional lead-acid battery negative electrode paste has the following problems:

[0004] 1. Insufficient conductive network: Conventional carbon black additives are prone to agglomeration, resulting in discontinuous electron transport paths and severe polarization during high-rate discharge;

[0005] 2. Severe sulfation: At low temperatures or in a partially charged state, a dense lead sulfate layer is easily formed on the surface of the negative electrode, blocking the reaction interface;

[0006] 3. Low-temperature failure: At low temperatures, the viscosity of the electrolyte increases sharply, ion diffusion is hindered, and the capacity drops sharply.

[0007] 4. Process defects: Atmospheric pressure mixing leads to uneven distribution of lead paste pores, and the kneading temperature is prone to fluctuation, which damages the structural stability of the expanding agent. Summary of the Invention

[0008] The purpose of this invention is to solve the problems in the background art by proposing a negative electrode paste for energy storage lead-acid batteries and its preparation process.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A negative electrode paste for energy storage lead-acid batteries and its preparation process, comprising the following components and parts by weight: 100 parts lead powder, 10-15 parts deionized water, 8-12 parts sulfuric acid, 2-5 parts composite conductive network agent, 1-4 parts step-type expansion agent, 1-2 parts composite carbon material, 1-2 parts low-temperature enhancement agent, and 0.1-0.5 parts conductive polymer.

[0011] Preferably, the composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a ratio of 5:2, and the aspect ratio of the aminated multi-walled carbon nanotubes is >1200, and the surface amino density is ≥3.0 mmol / g.

[0012] Preferably, the composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, and the number of graphene-coated carbon nanotubes is ≤5, the diameter is 20-50nm, and the length is 1-10μm.

[0013] Preferably, the stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 60-85 nm.

[0014] Preferably, the low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 6-9 nm and the fiber diameter is 80-180 nm.

[0015] Preferably, the fumed silica has a specific surface area of ​​380±20 m2 / g and its surface is hydrophobically treated with hexamethyldisilazane.

[0016] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0017] S1. Vacuum pore formation: Inject lead powder and 1 / 3 sulfuric acid into a twin-shaft vacuum mixer and stir for 8-12 minutes under a vacuum of -0.08±0.005MPa to obtain primary porous lead.

[0018] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 200±10 rpm for 30 min to obtain tertiary porous lead.

[0019] S3, Ultrasonic Activation: The step-type expanding agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 50-60 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0020] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it for 15-25 minutes at a constant temperature of 120±10 rpm and 45℃±1℃ until the viscosity reaches 25-35 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0021] Compared with existing technologies, the advantages of the lead paste for the negative electrode of energy storage lead-acid battery and its preparation process provided by the present invention are as follows:

[0022] 1. A dual composite conductive system is constructed by using composite conductive network agents and composite carbon materials. Then, the three-dimensional conductive network is optimized with the synergy of composite carbon materials. On the one hand, the internal resistance of the electrode is significantly reduced and the rate performance is improved. On the other hand, the electronic conduction efficiency is enhanced and the formation of lead sulfate passivation layer is suppressed, thereby simultaneously achieving high conductivity and enhanced electrode reaction kinetics.

[0023] 2. A multi-level porous structure can be constructed by using a step-type expansion agent composed of humic acid nanospheres and hydrophobic fumed silica. This provides volume buffer space to alleviate electrode expansion stress, while also enhancing electrolyte wettability and inhibiting the shedding of active materials. This synergistically inhibits negative electrode sulfation and improves electrode structural stability and cycle life.

[0024] 3. By selecting bismuth oxide quantum dot-modified graphitized carbon fiber as a low-temperature reinforcing agent, the synergistic effect of the highly active catalysis of quantum dots and the three-dimensional conductive network of the fiber carrier significantly improves the low-temperature capacity retention rate of the battery.

[0025] 4. By constructing bubble-free initial pores through vacuum pore-forming, maintaining the conductivity of carbon materials through argon-protected ball milling, achieving uniform dispersion of the step expansion agent to form secondary channels through ultrasonic activation, and precisely controlling the viscosity of lead paste through temperature-controlled kneading, a four-stage synergistic process is formed to optimize electrode manufacturing, thereby achieving the dual effect of improving coating consistency and structural integrity.

[0026] In summary, this invention significantly improves conductivity and low-temperature capacity retention by employing a dual composite conductive network agent and carbon materials to construct a dual composite conductive network, synergistically using a stepped expansion agent to construct a multi-level porous structure, and introducing bismuth oxide quantum dot-modified graphitized carbon fibers as a low-temperature reinforcing agent and fiber carrier to achieve a synergistic effect with the three-dimensional conductive network. Furthermore, through a four-stage synergistic manufacturing process involving vacuum pore formation, argon balloon milling, ultrasonic activation, and temperature-controlled kneading, the rate performance, structural stability, low-temperature capacity retention, and cycle life of lead-acid batteries are ultimately enhanced. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0028] Example 1

[0029] A negative electrode paste for energy storage lead-acid batteries comprises the following components and parts by weight: 100 parts lead powder, 10 parts deionized water, 8 parts sulfuric acid, 2 parts composite conductive network agent, 1 part stepped expansion agent, 1 part composite carbon material, 1 part low-temperature enhancement agent, and 0.1 parts conductive polymer.

[0030] The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio. The aminated multi-walled carbon nanotubes have an aspect ratio of 1300 and a surface amino density of 3.0 mmol / g. The composite conductive network agent and the conductive polymer construct a three-dimensional conductive network, which can reduce internal resistance and improve rate performance.

[0031] The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio. The graphene-coated carbon nanotubes have 5 layers, a diameter of 20 nm, and a length of 1 μm, which can enhance electron conduction and inhibit the formation of lead sulfate passivation layer.

[0032] The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the humic acid nanospheres have a diameter of 60 nm, which can provide buffer space and alleviate volume changes during charging and discharging.

[0033] The specific surface area of ​​fumed silica is 360 m2 / g, and the surface is hydrophobically treated with hexamethyldisilazane to enhance electrolyte wettability and reduce active material shedding. With the addition of a step-type expansion agent, it can synergistically suppress negative electrode sulfation and improve deep cycling capability.

[0034] The low-temperature enhancer is graphitized carbon fiber modified with bismuth oxide quantum dots, where the quantum dots have a diameter of 6 nm and the fiber diameter is 80 nm. The synergistic effect of the highly active catalysis of quantum dots and the three-dimensional conductive network of the fiber support significantly improves the low-temperature capacity retention of the battery.

[0035] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0036] S1. Vacuum pore formation: Lead powder and 1 / 3 sulfuric acid are injected into a twin-shaft vacuum mixer and stirred for 8 minutes under a vacuum of -0.075MPa to obtain primary porous lead and construct bubble-free initial pores.

[0037] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 190 rpm for 30 min to obtain tertiary porous lead and maintain the conductivity of carbon material.

[0038] S3, Ultrasonic Activation: The step-type expansion agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 50 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0039] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it for 15 minutes at a constant temperature of 110 rpm and 44°C until the viscosity reaches 25 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0040] The above-mentioned tertiary pores originate from the inherent nanopores of the composite carbon material and already exist after the ball milling process (S2), while the secondary pores are formed by the decomposition of the step expansion agent during the curing process, and their formation is later than that of the tertiary pores.

[0041] Through the above preparation steps, a four-stage synergistic process can be formed to optimize electrode manufacturing by constructing bubble-free initial pores through vacuum pore-forming, maintaining the conductivity of carbon materials through argon-protected ball milling, achieving uniform dispersion of step expansion agent to form secondary channels through ultrasonic activation, and precisely controlling the viscosity of lead paste through temperature-controlled kneading. This results in a dual improvement in coating consistency and structural integrity.

[0042] Example 2

[0043] Unlike Example 1, a negative electrode paste for an energy storage lead-acid battery comprises the following components and parts by weight: 100 parts lead powder, 11 parts deionized water, 9 parts sulfuric acid, 3 parts composite conductive network agent, 2 parts stepped expansion agent, 2 parts composite carbon material, 2 parts low-temperature enhancement agent, and 0.2 parts conductive polymer.

[0044] The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio, with the aminated multi-walled carbon nanotubes having an aspect ratio of 1500 and a surface amino density of 3.1 mmol / g.

[0045] The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, with the graphene-coated carbon nanotubes having 4 layers, a diameter of 30 nm, and a length of 3 μm.

[0046] The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 65 nm.

[0047] The specific surface area of ​​the fumed silica is 370 m² / g, and the surface is hydrophobically treated with hexamethyldisilazane.

[0048] The low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 7 nm and the fiber diameter is 100 nm.

[0049] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0050] S1. Vacuum pore formation: Lead powder and 1 / 3 sulfuric acid are injected into a twin-shaft vacuum mixer and stirred for 9 minutes under a vacuum of -0.08MPa to obtain primary porous lead.

[0051] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 195 rpm for 30 min to obtain tertiary porous lead.

[0052] S3, Ultrasonic Activation: The step-type expansion agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 54 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0053] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it for 18 minutes at a constant temperature of 115 rpm and 44.5℃ until the viscosity reaches 28 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0054] Example 3

[0055] Unlike Example 2, a negative electrode paste for an energy storage lead-acid battery comprises the following components and parts by weight: 100 parts lead powder, 12 parts deionized water, 10 parts sulfuric acid, 4 parts composite conductive network agent, 3 parts stepped expansion agent, 1 part composite carbon material, 1 part low-temperature enhancement agent, and 0.3 parts conductive polymer.

[0056] The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio, with the aminated multi-walled carbon nanotubes having an aspect ratio of 1400 and a surface amino density of 3.2 mmol / g.

[0057] The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, with the graphene-coated carbon nanotubes having 3 layers, a diameter of 40 nm, and a length of 5 μm.

[0058] The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 70 nm.

[0059] The specific surface area of ​​the fumed silica is 380 m² / g, and the surface is hydrophobically treated with hexamethyldisilazane.

[0060] The low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 7.5 nm and the fiber diameter is 120 nm.

[0061] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0062] S1. Vacuum pore formation: Lead powder and 1 / 3 sulfuric acid are injected into a twin-shaft vacuum mixer and stirred for 10 minutes under a vacuum of -0.082MPa to obtain primary pore lead.

[0063] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon replacement three times, the lead is ball-milled at 200 rpm for 30 min to obtain tertiary porous lead.

[0064] S3, Ultrasonic Activation: The step-type expanding agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 56 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0065] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it for 20 minutes at a constant temperature of 120 rpm and 45°C until the viscosity reaches 30 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0066] Example 4

[0067] Unlike Example 3, a negative electrode paste for an energy storage lead-acid battery comprises the following components and parts by weight: 100 parts lead powder, 14 parts deionized water, 11 parts sulfuric acid, 5 parts composite conductive network agent, 4 parts stepped expansion agent, 2 parts composite carbon material, 2 parts low-temperature enhancement agent, and 0.4 parts conductive polymer.

[0068] The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio, with the aminated multi-walled carbon nanotubes having an aspect ratio of 1600 and a surface amino density of 3.5 mmol / g.

[0069] The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, with the graphene-coated carbon nanotubes having 2 layers, a diameter of 45 nm, and a length of 8 μm.

[0070] The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 75 nm.

[0071] The specific surface area of ​​the fumed silica is 390 m² / g, and the surface is hydrophobically treated with hexamethyldisilazane.

[0072] The low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 8 nm and the fiber diameter is 150 nm.

[0073] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0074] S1. Vacuum pore formation: Lead powder and 1 / 3 sulfuric acid are injected into a twin-shaft vacuum mixer and stirred for 11 minutes under a vacuum of -0.084MPa to obtain primary pore lead.

[0075] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 205 rpm for 30 min to obtain tertiary porous lead.

[0076] S3, Ultrasonic Activation: The step-type expansion agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 58 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0077] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it at a constant temperature of 125 rpm and 45.5℃ for 24 minutes until the viscosity reaches 32 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0078] Example 5

[0079] Unlike Example 4, a negative electrode paste for an energy storage lead-acid battery comprises the following components and parts by weight: 100 parts lead powder, 15 parts deionized water, 12 parts sulfuric acid, 4 parts composite conductive network agent, 3 parts stepped expansion agent, 1 part composite carbon material, 1 part low-temperature enhancement agent, and 0.5 parts conductive polymer.

[0080] The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio, with the aminated multi-walled carbon nanotubes having an aspect ratio of 1250 and a surface amino density of 3.6 mmol / g.

[0081] The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, with the graphene-coated carbon nanotubes having 4 layers, a diameter of 50 nm, and a length of 10 μm.

[0082] The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 80 nm.

[0083] The specific surface area of ​​the fumed silica is 400 m² / g, and the surface is hydrophobically treated with hexamethyldisilazane.

[0084] The low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 9 nm and the fiber diameter is 180 nm.

[0085] A process for preparing lead paste for the negative electrode of an energy storage lead-acid battery includes the following steps:

[0086] S1. Vacuum pore formation: Lead powder and 1 / 3 sulfuric acid are injected into a twin-shaft vacuum mixer and stirred for 12 minutes under a vacuum of -0.085MPa to obtain primary pore lead.

[0087] S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 210 rpm for 30 min to obtain tertiary porous lead.

[0088] S3, Ultrasonic Activation: The step-type expanding agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 60 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead.

[0089] S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it at a constant temperature of 130 rpm and 46°C for 25 minutes until the viscosity reaches 35 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.

[0090] To further clarify, the aforementioned fixed connection should be interpreted broadly unless otherwise explicitly specified and limited. For example, it may be welding, gluing, or integral molding, or other conventional methods well known to those skilled in the art.

[0091] 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 equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A negative electrode paste for an energy storage lead-acid battery, characterized in that, It includes the following components and parts by weight: 100 parts lead powder, 10-15 parts deionized water, 8-12 parts sulfuric acid, 2-5 parts composite conductive network agent, 1-4 parts step expansion agent, 1-2 parts composite carbon material, 1-2 parts low temperature reinforcing agent, and 0.1-0.5 parts conductive polymer.

2. The lead paste for the negative electrode of an energy storage lead-acid battery and its preparation process according to claim 1, characterized in that, The composite conductive network agent is composed of aminated multi-walled carbon nanotubes and sulfonated lignin / polyacrylamide composites in a 5:2 ratio, and the aspect ratio of the aminated multi-walled carbon nanotubes is >1200, with a surface amino density ≥3.0 mmol / g.

3. The lead paste for the negative electrode of an energy storage lead-acid battery and its preparation process according to claim 1, characterized in that, The composite carbon material is composed of graphene-coated carbon nanotubes and activated carbon in a 2:1 ratio, and the number of graphene-coated carbon nanotubes is ≤5, the diameter is 20-50nm, and the length is 1-10μm.

4. The lead paste for the negative electrode of an energy storage lead-acid battery and its preparation process according to claim 1, characterized in that, The stepped expansion agent is composed of humic acid nanospheres and fumed silica in a 3:1 ratio, and the diameter of the humic acid nanospheres is 60-85 nm.

5. The lead paste for the negative electrode of an energy storage lead-acid battery and its preparation process according to claim 1, characterized in that, The low-temperature reinforcing agent is graphitized carbon fiber modified with bismuth oxide quantum dots, wherein the quantum dots have a diameter of 6-9 nm and the fiber diameter is 80-180 nm.

6. The lead paste for the negative electrode of an energy storage lead-acid battery and its preparation process according to claim 4, characterized in that, The fumed silica has a specific surface area of ​​380±20 m2 / g and its surface is hydrophobically treated with hexamethyldisilazane.

7. A preparation process for the negative electrode lead paste of an energy storage lead-acid battery according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Vacuum pore formation: Inject lead powder and 1 / 3 sulfuric acid into a twin-shaft vacuum mixer and stir for 8-12 minutes under a vacuum of -0.08±0.005MPa to obtain primary porous lead. S2. Construction of conductive network: Composite carbon material, composite conductive network agent and conductive polymer are added to the porous framework lead obtained in S1. After argon gas replacement three times, the lead is ball-milled at 200±10 rpm for 30 min to obtain tertiary porous lead. S3, Ultrasonic Activation: The step-type expanding agent and the remaining sulfuric acid are premixed into a slurry with a viscosity of 50-60 Pa·s, and injected together with the tertiary porous lead obtained in S2 into a titanium alloy ultrasonic reactor. The mixture is ultrasonically vibrated at 40 kHz for 20 min to obtain secondary porous lead. S4. Temperature control and shaping: Mix the low-temperature enhancer with the secondary porous lead obtained in S3, and then inject deionized water in three batches with a 2-minute interval between each batch. Then, feed the mixture into a twin-screw kneader and knead it for 15-25 minutes at a constant temperature of 120±10 rpm and 45℃±1℃ until the viscosity reaches 25-35 Pa·s, thus obtaining the negative electrode lead paste for energy storage lead-acid batteries.