A method of manufacturing a solid state electrolyte lead acid battery

Abstract

The application belongs to the technical field of new material preparation, and discloses a preparation method of a solid-state electrolyte lead-acid storage battery. The method replaces the traditional liquid electrolyte with the solid-state electrolyte, has good thermal stability and chemical stability, is not easy to burn and leak, and can significantly improve the safety of the battery. Due to the stability and good interface compatibility of the solid-state electrolyte, the solid-state electrolyte lead-acid storage battery has smaller loss of electrode materials in the charging and discharging process, has a longer cycle life, can still maintain high performance after multiple charging and discharging, and reduces the frequency and cost of battery replacement.

Description

Technical Field

[0001] This application belongs to the field of new materials technology, specifically relating to a method for preparing a solid electrolyte lead-acid battery. Background Technology

[0002] Lead-acid batteries, as one of the most mature electrochemical energy storage systems, occupy an important position in fields such as automotive starting power supplies and industrial energy storage due to their advantages of low cost, high recyclability, and high reliability. However, traditional lead-acid batteries use liquid sulfuric acid electrolyte, which has the following problems: liquid electrolyte is prone to leakage, leading to internal short circuits and shell corrosion, especially under vibration or tilting conditions, which exacerbates the risk. Statistics show that about 23% of lead-acid battery failures are related to electrolyte leakage. Under overcharging or high-temperature environments, the water in the electrolyte decomposes to produce hydrogen and oxygen, posing an explosion hazard, and requiring regular maintenance and water replenishment. In addition, during deep discharge, the phase transition between the positive electrode PbO2 and the negative electrode Pb causes the active material to detach, and the cycle life of conventional batteries is only about 300 cycles.

[0003] Lithium-ion batteries are superior to lead-acid batteries in many aspects, but their manufacturing and operating costs are much higher, and their thermal stability is poor, especially at high temperatures where capacity retention drops significantly. Developing solid-state electrolyte lead-acid batteries is of great research value; however, inorganic solid-state electrolytes (such as oxide ceramics) have poor compatibility and interfacial contact with lead-based electrodes; polymer electrolytes (such as PEO-based electrolytes) have low ion mobility in lead-acid systems and are prone to decomposition at high temperatures. Therefore, the research and development of solid-state electrolytes is the core technological challenge in developing solid-state electrolyte lead-acid batteries. Summary of the Invention

[0004] Objective of the Invention: To address the shortcomings of existing technologies, this application provides a method for preparing a solid-state electrolyte lead-acid battery. The lead-acid battery prepared using this method eliminates the leakage and corrosion problems associated with liquid electrolytes, resulting in higher safety and a longer lifespan. Furthermore, it exhibits better high-temperature performance, enabling it to adapt to special high-temperature operating environments.

[0005] Technical solution: The method for preparing a solid electrolyte lead-acid battery provided by the present invention includes the following steps: Step 1, taking a thickness of 1.2-1.5 mm and a mesh density of 8-12 pores / cm 2Two alloy grid plates are used, one coated with positive electrode lead paste and the other with negative electrode lead paste, with a coating thickness of 0.8-1.2 mm. The coated plates are pre-cured for 20-24 hours in an environment with 55-65% humidity and 40-50℃ to form stable green plates. In a humid and hot environment, the lead oxide in the lead paste reacts with sulfuric acid to form tribasic lead sulfate (3PbO·PbSO4·H2O), forming a stable porous structure and enhancing the permeability of subsequent electrolytes. For this invention, excessive humidity will cause rapid crystallization and cracking, while excessively low temperature will result in incomplete curing; a humidity of 50% and a temperature of 55℃ are preferred.

[0006] Step 2: Using a TPU nanofiber membrane as the matrix material, its nanofiber structure (pore size between 50-200 nm) allows sol-gel penetration to form an interpenetrating network while mitigating volume expansion stress during charging and discharging. The TPU membrane is first immersed in an MXene dispersion for 5-6 minutes, followed by vacuum drying at 55-60°C. Then, a CNT dispersion is sprayed onto its surface at a pressure of 0.2 MPa, repeating this process several times to form a bilayer conductive structure. The MXene layer preferentially adsorbs protons (H+), thus constructing an ion transport channel; the CNT layer is responsible for constructing electronic conduction pathways, achieving proton-electron dual-pathway separation and effectively reducing interfacial polarization loss. Next, the structure was immersed in a silicon source sol and allowed to stand for 30-40 minutes to allow it to permeate. Then, an appropriate amount of ammonia was added to adjust the pH to 9-10, and the mixture was gelled at room temperature for 10-12 hours to promote the sol-gel transition and form a mesoporous SiO2 framework. This was followed by drying to obtain a porous composite structure. Then, the porous composite structure was immersed in a 1-5M sulfuric acid solution, and the pH was adjusted to 2-4. Adsorption was carried out at room temperature with shaking for 10-12 hours. The sulfuric acid was adsorbed by forming hydrogen bonds with surface hydroxyl groups (-Si-OH). Finally, the saturated sample was vacuum dried at 80-85℃ to condense and form -Si-O-SO3H groups, creating a stable solid proton conductor, thus obtaining the electrolyte layer.

[0007] Step 3: Stack the positive electrode plate, electrolyte layer, and negative electrode plate in sequence, and use a hot pressing process (temperature 78-82℃, pressure 5MPa) to make them tightly bonded. The TPU softens at 80℃ (close to the glass transition temperature), and the pressure promotes the physical-chemical bonding between the electrolyte layer and the electrode plate interface. The interface porosity is <5%, and the contact resistance is reduced by more than 30%, forming a "sandwich" structure that does not require the injection of liquid electrolyte.

[0008] Specifically, the positive electrode lead paste mainly comprises: 60-70 parts of Barton lead powder (oxidation degree 70%-88%), 20-30 parts of ball milled lead powder, and 0.5-1 parts of barium sulfate. The trace amount of barium sulfate is preferentially adsorbed on the surface of PbO2 crystal nuclei, which hinders the irreversible crystallization of lead sulfate (PbSO4) and delays the capacity decay caused by positive electrode sulfation.

[0009] Specifically, the negative electrode lead paste mainly consists of 90-100 parts pure lead powder and 0.3-0.8 parts stannous sulfate. The addition of trace amounts of stannous sulfate can inhibit lead dendrite growth (by reducing the nucleation energy through adsorption on the lead surface) and simultaneously reduce the hydrogen evolution overpotential, thus minimizing the impact of hydrogen evolution side reactions on battery cycle life. The positive electrode barium sulfate and the negative electrode stannous sulfate synergistically inhibit irreversible sulfation, offsetting the capacity decay problem caused by interfacial stress in solid-state batteries.

[0010] Specifically, the MXene dispersion consists of Ti3C2T x MXene powder (1–2 mg / mL) is dispersed in deionized water and ultrasonically treated for 30–40 minutes. It can be exfoliated into single-layer or few-layer nanosheets, which enhances the uniformity of dispersion and avoids clogging of the electrolyte layer pores due to agglomeration, thus obtaining an MXene dispersion.

[0011] Specifically, the CNT dispersion is prepared by dispersing carboxylated carbon nanotubes (0.5–1 wt%) and polyvinylpyrrolidone (PVP) in ethanol and sonicating for 50–60 minutes. The carboxylated CNTs are stably dispersed through electrostatic repulsion, and PVP acts as a surfactant to further prevent aggregation, thus obtaining the CNT dispersion.

[0012] Specifically, the silicon source sol is prepared by mixing tetraethyl orthosilicate (TEOS), ethanol, and deionized water, adding hydrochloric acid to catalyze hydrolysis, and hydrochloric acid catalyzing the hydrolysis of TEOS to generate silanol groups (Si-OH), which then condense to form a three-dimensional Si-O-Si network; the viscosity of the sol can be adjusted by controlling the TEOS concentration to 5-20 wt%, ensuring that a mesoporous structure with a pore size of 2-50 nm is formed after subsequent gelation, and stirring for 30-40 minutes to form the silicon source sol.

[0013] Furthermore, in step 2, an electrolyte layer is prepared using a TPU / MWCNT composite fiber membrane as the matrix material, following the same steps described above. Because MWCNTs are embedded within the TPU fibers, a three-dimensional electron conduction network is directly constructed within the matrix, forming a bilayer electronic pathway with the subsequently sprayed CNT layer. This significantly reduces interfacial contact resistance and decreases electron transport polarization losses. Simultaneously, surface defect sites on MWCNTs may adsorb more silanol groups (-Si-OH) through hydrogen bonding or π-π interactions, generating denser sulfonic acid groups (-SO3H) during subsequent sulfuric acid treatment, thus improving proton conductivity. In addition, the addition of MWCNTs enhances the thermal stability of the TPU matrix, reducing the risk of electrolyte structure collapse at high temperatures. The specific steps are as follows: The TPU / MWCNT composite fiber membrane is immersed in MXene dispersion for 5-6 minutes, followed by vacuum drying at 55-60℃. Then, CNT dispersion is sprayed onto its surface at a pressure of 0.2 MPa, repeated several times. Afterward, it is immersed in a silicon source sol and allowed to stand for 30-40 minutes to allow penetration. An appropriate amount of ammonia is added to adjust the pH to 9-10, and gelation is carried out at room temperature for 10-12 hours, followed by drying to obtain a porous composite structure. The porous composite structure is then immersed in a 1-5M sulfuric acid solution, the pH is adjusted to 2-4, and adsorption is carried out at room temperature with shaking for 10-12 hours. After adsorption saturation, vacuum drying is performed at 80-85℃ to form a stable solid proton conductor, thus obtaining the desired electrolyte layer.

[0014] Furthermore, in step 2, the porous composite structure is immersed in a sulfuric acid solution (concentration 1–5M), the pH is adjusted to 2–4, a voltage of 1–2V is applied, and adsorption is carried out at room temperature with shaking for 6 hours. After adsorption saturation, it is vacuum dried at 80°C for 4 hours. Electrochemical polarization accelerates H2O adsorption. + and SO4 2- Ions can penetrate deep into porous structures, effectively improving migration efficiency and reducing reaction time by approximately half. Furthermore, electroosmosis removes air bubbles from the pores, further achieving effective pore filling and increasing pore utilization.

[0015] Furthermore, in step 2, the porous composite structure is immersed in a sulfuric acid solution (concentration 1–5M), the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After adsorption saturation, it is vacuum dried at 80°C for 4 hours. The structure is then immersed in a sulfuric acid solution (concentration 1–5M), the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After adsorption saturation, it is vacuum dried at 80°C for 4 hours.

[0016] Furthermore, in step 2, the porous composite structure is immersed in a sulfuric acid solution (concentration 1–5M), the pH is adjusted to 2–4, and the structure is shaken and adsorbed at room temperature for 12 hours. After removal, it is soaked in an ethanol solution containing 3-aminopropyltriethoxysilane (APTES) coupling agent (concentration 1wt%) for 2 hours to form a Si-O-Si covalent network that locks in the sulfuric acid.

[0017] Beneficial effects: Compared with traditional lead-acid batteries, the electrolyte in the battery of this invention is solid-state, exhibiting excellent thermal and chemical stability, and is less prone to combustion and leakage, thus significantly improving battery safety. Due to the stability and good interfacial compatibility of the solid-state electrolyte, the electrode material loss during charging and discharging is less, resulting in a longer cycle life. It maintains high performance even after multiple charge-discharge cycles, reducing the frequency and cost of battery replacement.

[0018] This invention solves the problem of poor compatibility between inorganic solid electrolytes such as oxide ceramics and lead-based electrodes, as well as the problem of low ion mobility of polymer electrolytes such as PEO-based electrolytes in lead-acid systems. The solid-state lead-acid battery of this invention employs a multi-stage composite electrolyte design: MXene (ion conduction) + CNT (electron conduction) + SiO2 (solid acid framework) synergistically enhance interfacial charge transfer efficiency. Furthermore, humidity / temperature control of lead paste crystallization and sol penetration depth ensures close contact between the active material and the electrolyte. The solid electrolyte layer of this invention combines ion conduction and mechanical support functions, resulting in a battery energy density increase of over 50% compared to traditional lead-acid batteries.

[0019] The method described in this invention uses a solid electrolyte instead of a traditional liquid electrolyte, resulting in better high-temperature performance. Even at extreme temperatures above 60°C, it maintains stable charge-discharge performance. The batteries prepared by this method are suitable for special high-temperature applications, such as backup power in high-temperature industrial settings like metallurgy and chemical engineering, solar energy storage systems in desert areas, communication base stations in tropical climates, and emergency power supply for mining equipment in enclosed high-temperature environments. This provides safe and reliable energy support for special high-temperature scenarios. Attached Figure Description

[0020] Figure 1 This is a SEM image of the matrix material used in the examples. Detailed Implementation

[0021] The technical solution of this application will be described in detail below through embodiments, but the scope of protection of this application is not limited to the embodiments described. All quantities mentioned in this invention are by weight.

[0022] Example 1

[0023] A thickness of 1.2 mm and a mesh density of 10 holes / cm² are used. 2 Two alloy grid plates are used, one coated with positive electrode lead paste and the other with negative electrode lead paste, with a coating thickness of 1.0±0.2mm. The main components of the positive electrode lead paste include: 70 parts Barton lead powder (oxidation degree 70%-88%), 20 parts ball-milled lead powder, and 0.5-1 parts barium sulfate; the main components of the negative electrode lead paste include: 100 parts pure lead powder and 0.3-0.8 parts stannous sulfate. After coating, the plates are pre-cured for 24 hours at 60% humidity and 45℃ to form stable green plates for later use.

[0024] Ti3C2T x MXene powder (1.5 mg / mL) was dispersed in deionized water and sonicated for 30 minutes to obtain an MXene dispersion for later use.

[0025] Carboxylated carbon nanotubes (1 wt%) and polyvinylpyrrolidone (PVP) were dispersed in ethanol and sonicated for 1 hour to obtain a CNT dispersion for later use.

[0026] Tetraethyl orthosilicate (TEOS), ethanol, and deionized water were mixed in a molar ratio of 1:4:4. 0.1M hydrochloric acid was added to catalyze hydrolysis. The TEOS concentration was controlled at 8wt%. The mixture was stirred for 30 minutes to form a silica sol for later use.

[0027] Using TPU nanofiber membranes as the matrix material, the TPU membranes were immersed in MXene dispersion for 5 minutes and then vacuum dried at 60°C. Subsequently, CNT dispersion was sprayed onto the membrane at a pressure of 0.2 MPa, repeated three times. The membranes were then immersed in a silicon source sol and allowed to stand for 30 minutes to allow penetration. Ammonia was then added to adjust the pH to 9–10, and the membranes were gelled at room temperature for 12 hours, followed by drying to form a porous composite structure. This structure was then immersed in a 2.5 M sulfuric acid solution, with the pH adjusted to 2–4, and adsorbed at room temperature with shaking for 12 hours. The saturated sample was then vacuum dried at 80°C for 4 hours to obtain the electrolyte layer.

[0028] The positive electrode plate, electrolyte layer, and negative electrode plate are stacked in sequence and then tightly bonded together using a hot-pressing process (temperature 80℃, pressure 5MPa) to form a sandwich structure.

[0029] Example 2

[0030] The main steps of Example 2 are roughly the same as those of Example 1, except that: the composite structure is immersed in sulfuric acid solution (concentration 2.5M), the pH is adjusted to 2–4, a voltage of 1–2V is applied, and the adsorption is carried out by shaking at room temperature for 6 hours. The saturated sample is then vacuum dried at 80°C for 4 hours to obtain the electrolyte layer.

[0031] Test Item 1 (Cycle Life Test)

[0032] 1. Standard charge / discharge procedure

[0033] Charge and discharge cycle at 1C rate at room temperature (25℃): charge to full and let stand for 30 minutes; discharge to cutoff voltage (e.g., 1.75V for lead-acid batteries, 3.0V for lithium batteries), and record the capacity of each cycle.

[0034] 2. Determination of End of Life

[0035] Record the number of cycles when the discharge capacity decays to 80% of the initial capacity.

[0036] Test Item 2 (Safety and Thermal Runaway Risk Test)

[0037] Needle prick test: using A steel needle is used to puncture the battery at a speed of 25 mm / s to monitor temperature changes and whether it catches fire or explodes.

[0038] Compression test: Apply 13kN pressure until the battery deforms by 30%, and observe whether thermal runaway occurs.

[0039] The performance comparison of the above embodiments with traditional lead-acid batteries and lithium batteries is shown in the table below:

[0040]

[0041] As can be seen from the above, this invention has higher safety and cycle life compared to traditional batteries. Compared to lithium batteries, it has a significant cost advantage.

[0042] Test Item 3 (High-Temperature Environment Charging and Discharging)

[0043] Place the battery in a constant temperature and humidity test chamber and heat it to the target temperature at a rate of 1℃ / min. Keep it at this temperature for 4 hours to ensure uniform internal temperature.

[0044] Charging: Charge to full capacity at a rate of 0.1C (2.45V for lead-acid batteries, 4.2V for lithium batteries); Discharging: Discharge to the cutoff voltage at a rate of 0.2C, and record the discharge capacity.

[0045] Capacity retention rate calculation: Retention rate (%) = (High-temperature discharge capacity ÷ Nominal capacity at room temperature) × 100%

[0046]

[0047] As can be seen from the above, the present invention has better high-temperature performance compared with traditional lead-acid batteries and lithium batteries.

[0048] Example 3

[0049] The main steps of Example 3 are roughly the same as those of Example 1, except that: the porous composite structure is immersed in sulfuric acid solution (concentration 2.5M), the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After the adsorption is saturated, it is vacuum dried at 80°C for 4 hours; the structure is then immersed in sulfuric acid solution (concentration 2.5M), the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After the adsorption is saturated, it is vacuum dried at 80°C for 4 hours to obtain the electrolyte layer.

[0050] Example 4

[0051] The main steps of Example 4 are roughly the same as those of Example 1, except that: the porous composite structure is immersed in sulfuric acid solution (concentration 2.5M), the pH is adjusted to 2–4, and the adsorption is carried out at room temperature with shaking for 12 hours. After being taken out, it is soaked in ethanol solution containing 3-aminopropyltriethoxysilane (APTES) coupling agent (concentration 1wt%) for 2 hours to obtain the electrolyte layer.

[0052] Example 5

[0053] A thickness of 1.2 mm and a mesh density of 10 holes / cm² are used. 2 Two alloy grid plates are used, one coated with positive electrode lead paste and the other with negative electrode lead paste, with a coating thickness of 1.0±0.2mm. The main components of the positive electrode lead paste include: 70 parts Barton lead powder (oxidation degree 70%-88%), 20 parts ball-milled lead powder, and 0.5-1 parts barium sulfate; the main components of the negative electrode lead paste include: 100 parts pure lead powder and 0.3-0.8 parts stannous sulfate. After coating, the plates are pre-cured for 24 hours at 60% humidity and 45℃ to form stable green plates for later use.

[0054] Ti3C2T x MXene powder (1.5 mg / mL) was dispersed in deionized water and sonicated for 30 minutes to obtain an MXene dispersion for later use.

[0055] Carboxylated carbon nanotubes (1 wt%) and polyvinylpyrrolidone (PVP) were dispersed in ethanol and sonicated for 1 hour to obtain a CNT dispersion for later use.

[0056] Tetraethyl orthosilicate (TEOS), ethanol, and deionized water were mixed in a molar ratio of 1:4:4. 0.1M hydrochloric acid was added to catalyze hydrolysis. The TEOS concentration was controlled at 8wt%. The mixture was stirred for 30 minutes to form a silica sol for later use.

[0057] Using a TPU / PVP composite nanofiber membrane as the matrix material, the sample was impregnated with MXene dispersion for 5 minutes and then vacuum-dried at 60°C. Subsequently, a CNT dispersion was sprayed onto the membrane at a pressure of 0.2 MPa, repeated three times. The membrane was then immersed in a silicon source sol and allowed to stand for 30 minutes to allow it to permeate. Ammonia was then added to adjust the pH to 9–10, and the membrane was gelled at room temperature for 12 hours, followed by drying to form a porous composite structure. This structure was then immersed in a 2.5 M sulfuric acid solution, with the pH adjusted to 2–4, and a voltage of 1–2 V applied for adsorption at room temperature with shaking for 6 hours. The saturated sample was then vacuum-dried at 80°C for 4 hours to obtain the electrolyte layer.

[0058] The positive electrode plate, electrolyte layer, and negative electrode plate are stacked in sequence and then tightly bonded together using a hot-pressing process (temperature 80℃, pressure 5MPa) to form a sandwich structure.

[0059] Example 6

[0060] The main steps of Example 6 are largely the same as those of Example 5, except that TPU / MWCNT composite nanofiber membrane is used as the matrix material.

[0061] SEM images (10 μm) of the matrix materials used in Examples 2, 5, and 6. Figure 1 As shown in the figure, a: TPU nanofiber membrane, b: TPU / PVP composite nanofiber membrane, c: TPU / MWCNT composite nanofiber membrane. The performance parameters of the matrix materials used in Examples 2, 5, and 6 are shown in the table below:

[0062]

[0063] The performance parameters of the batteries prepared in Examples 2, 5, and 6 are compared in the table below:

[0064]

[0065] As can be seen from the above data, Example 5 is not significantly different from Example 2, while Example 6 is superior. For low-cost scenarios, the preparation method described in Example 2 can be selected; for high-power or high-temperature scenarios, the preparation method described in Example 6 can be selected.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit this application.

Claims

1. A method for preparing a lead-acid battery with a solid electrolyte, characterized in that, Includes the following steps: Step 1: Take two alloy grid plates with a thickness of 1.2-1.5 mm and a grid density of 8-12 pores / cm². Coat one plate with positive electrode lead paste and the other with negative electrode lead paste, with a coating thickness of 0.8-1.2 mm. Pre-cur the coated plates in an environment with a humidity of 55-65% and a temperature of 40-50℃ for 20-24 hours to form a stable green electrode plate. Step 2: Using TPU nanofiber membrane as the matrix material, it is first immersed in MXene dispersion for 5-6 minutes, followed by vacuum drying at 55-60℃. Then, CNT dispersion is sprayed onto its surface at a pressure of 0.2 MPa, and this process is repeated several times to form a double-layer conductive structure. After that, it is immersed in silicon source sol and allowed to stand for 30-40 minutes to penetrate. Then, an appropriate amount of ammonia is added to adjust the pH to 9-10, and gelation is carried out at room temperature for 10-12 hours. Then, it is dried to obtain a porous composite structure. Next, the porous composite structure is immersed in a 1-5 M sulfuric acid solution, the pH is adjusted to 2-4, and it is shaken and adsorbed at room temperature for 10-12 hours. After adsorption saturation, it is vacuum dried at 80-85℃ to obtain the electrolyte layer. Step 3: Stack the positive electrode plate, electrolyte layer, and negative electrode plate in sequence, and use a hot pressing process to tightly bond them together to form a "sandwich" structure that does not require the injection of liquid electrolyte, thus obtaining the lead-acid battery.

2. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, The positive electrode lead paste mainly comprises: 60-70 parts of Barton lead powder, 20-30 parts of ball-milled lead powder, and 0.5-1 parts of barium sulfate.

3. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, The negative electrode lead paste mainly consists of: 90-100 parts of pure lead powder and 0.3-0.8 parts of stannous sulfate.

4. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, The MXene dispersion: Ti3C2T x MXene powder was dispersed in deionized water and ultrasonically treated for 30-40 minutes to obtain an MXene dispersion.

5. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, The CNT dispersion is obtained by dispersing carboxylated carbon nanotubes and polyvinylpyrrolidone in ethanol and sonicating for 50-60 minutes.

6. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, The silicon source sol is formed by mixing tetraethyl orthosilicate, ethanol, and deionized water, adding hydrochloric acid for catalytic hydrolysis, controlling the TEOS concentration at 5-20 wt%, and stirring for 30-40 minutes.

7. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, In step 2, the TPU / MWCNT composite fiber membrane is immersed in MXene dispersion for 5-6 minutes, followed by vacuum drying at 55-60°C. Then, CNT dispersion is sprayed onto its surface at a pressure of 0.2 MPa, repeated several times. Afterward, it is immersed in silicon source sol and allowed to stand for 30-40 minutes to penetrate. An appropriate amount of ammonia is added to adjust the pH to 9-10, and gelation is carried out at room temperature for 10-12 hours, followed by drying to obtain a porous composite structure. This porous composite structure is then immersed in a 1-5 M sulfuric acid solution, the pH is adjusted to 2-4, and adsorption is carried out at room temperature with shaking for 10-12 hours. After adsorption saturation, it is vacuum dried at 80-85°C to obtain the electrolyte layer.

8. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, In step 2, the porous composite structure is immersed in sulfuric acid solution, the pH is adjusted to 2–4, a voltage of 1–2 V is applied, and the adsorption is carried out by shaking at room temperature for 6 hours. After the adsorption is saturated, it is dried under vacuum at 80°C for 4 hours to obtain the electrolyte layer.

9. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, In step 2, the porous composite structure is immersed in a sulfuric acid solution with a concentration of 1–5 M, the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After the adsorption is saturated, it is dried under vacuum at 80°C for 4 hours. The structure is then immersed in sulfuric acid solution again, the pH is adjusted to 2–4, and the adsorption is carried out by shaking at room temperature for 12 hours. After the adsorption is saturated, it is dried under vacuum at 80°C for 4 hours to obtain the electrolyte layer.

10. The method for preparing a lead-acid battery with a solid electrolyte according to claim 1, characterized in that, In step 2, the porous composite structure is immersed in sulfuric acid solution, the pH is adjusted to 2–4, and the adsorption is carried out at room temperature with shaking for 12 hours. After removal, it is soaked in ethanol solution containing 1 wt% 3-aminopropyltriethoxysilane coupling agent for 2 hours to obtain the electrolyte layer.

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