A lead-acid battery titanium-based positive plate grid and a preparation method thereof

Abstract

The application discloses a titanium-based positive plate grid of lead-acid battery and a preparation method thereof. The titanium-based positive plate grid of lead-acid battery comprises a titanium metal base body, an intermediate layer and a surface lead metal layer. The intermediate layer is composed of a metal oxide with good conductivity and corrosion resistance, is prepared by a thermal oxidation method, can prevent the titanium base body from being oxidized and improve the conductivity of the base body and the surface lead metal layer. The surface lead layer is prepared by an electrodeposition method. The positive plate grid structure of the lead-acid battery is a sandwich type structure of titanium / intermediate layer / lead, has the characteristics of light weight, strong corrosion resistance, good conductivity and good combination with active substances and the like, and can be used as a positive plate of a high-energy-density long-service-life lead-acid battery, a bipolar lead-acid battery plate and a current collector of other related batteries.

Description

Technical Field

[0001] This invention relates to a titanium-based positive electrode grid for lead-acid batteries and its preparation method, belonging to the field of advanced lead-acid battery technology. This titanium-based grid can be used in high-energy-density, long-life lead-acid battery positive electrodes, as well as in bipolar lead-acid battery electrodes, and can also be used as a current collector in other related batteries. Background Technology

[0002] As is well known, lead-acid batteries are one of the oldest and most widely used rechargeable batteries to date. Despite the challenges posed by high-energy rechargeable batteries, lead-acid batteries have become one of the most important energy storage batteries due to their mature technology, high safety, good low-temperature performance, low manufacturing cost, high recycling rate (up to 99%), and a sound manufacturing base. However, compared with advanced rechargeable batteries such as lithium-ion batteries, lead-acid batteries still have significant shortcomings: one is their low actual energy density, approximately 30-40 Wh / kg. -1 It only accounts for 123 Wh / kg of the theoretical specific energy. -1 The battery's energy density ranges from 24.4% to 32.5%, primarily due to low utilization of active electrode materials and the large mass of the lead grid, which accounts for 20-30% of the battery's weight. Secondly, corrosion and softening of the positive electrode grid are significant issues. During charging, the lead dioxide positive electrode is polarized to a higher potential, causing the lead alloy positive electrode grid, primarily composed of lead, to oxidize into lead oxides. This corrosion and fracture prevents the grid from providing support for the active materials, leading to battery failure. Therefore, improving the energy density of lead-acid batteries and solving the problem of positive electrode grid corrosion are urgent priorities.

[0003] One effective way to improve the energy density of lead-acid batteries is to replace traditional lead-based grids with lightweight grids. It is believed that lead alloy grids form a corrosion layer between the grid and the battery active material, ensuring the bonding between the grid and the active material. Therefore, a layer of metallic lead is typically plated onto a lightweight material, which most realistically simulates a lead alloy grid; materials such as aluminum and carbon are commonly used. Aluminum substrates, plated with lead via a melt-plating method, are often used for the negative electrode grids of lead-acid batteries; however, an aluminum oxide passivation film easily forms on the aluminum substrate surface. Carbon substrates have been extensively studied for grid materials, such as pitch carbon, honeycomb carbon, glassy carbon, and graphite, which are used directly or by plating a layer of metallic lead for both positive and negative electrode grids in lead-acid batteries. Although carbon substrates have good electrical conductivity, they inherently have low mechanical strength. Furthermore, even with a lead plating layer, carbon-based positive electrode grids are easily oxidized.

[0004] Titanium and its alloys have attracted considerable interest due to their excellent electrical conductivity, low density, strong corrosion resistance, and high mechanical strength. Research has shown that only one-tenth the amount of titanium required for lead grids is needed to produce lead-acid batteries of the same capacity, thus reducing battery weight and increasing energy density. However, titanium readily forms a non-conductive titanium dioxide film on its surface under sulfuric acid and high-potential environments, preventing the titanium substrate from being directly used as the grid material. Traditionally, titanium / oxide coatings or titanium / oxide coatings / lead dioxide are used as the positive electrode current collector in lead-acid batteries. Examples include titanium / ruthenium dioxide grids, titanium / ruthenium dioxide / lead dioxide grids, titanium / tin dioxide grids, and titanium / tin-antimony coating / lead dioxide grids, all of which offer some corrosion resistance. Ruthenium dioxide has a low oxygen evolution overpotential, leading to decreased battery charge / discharge efficiency and severe self-discharge. While tin-antimony oxide coatings have a high oxygen evolution overpotential, the bonding between the grid and the active material is poor, causing the active material to easily detach during operation, resulting in battery failure.

[0005] Chinese patent application 201010524211.7, "Lightweight Grid for Lead-Acid Battery and its Preparation Method," uses titanium as the substrate, and the conductive layer on the surface is applied using mechanical pressing. The conductive layer and the grid substrate are not firmly bonded, making it prone to damage during battery operation. Chinese patent application 200610110234.7, "Foamed Titanium-Based Positive and Negative Electrode Grid Material for Lead-Acid Battery and its Manufacturing Method," uses foamed titanium as the substrate, then a silver plating layer as the conductive layer, and finally electroplated lead dioxide as the positive electrode grid for the lead-acid battery. This positive electrode grid has poor adhesion to the battery's active material, and the use of silver plating significantly increases the battery cost. Chinese patent applications 201410166118.1, "A method for preparing a titanium / titanium suboxide / lead composite substrate," and 201210295358.2, "Titanium-based titanium suboxide plate and its manufacturing method," both use titanium suboxide as an anti-corrosion coating. However, titanium suboxide will still turn into non-conductive titanium dioxide under sulfuric acid and positive electrode potential, making the grid prone to failure. In Chinese patent application 200910219598.2, "Ti-0.2Pd titanium alloy-based foamed lead negative electrode grid for lead-acid batteries," Ti-0.2Pd titanium alloy is used as the substrate. Due to the use of 20% precious metal palladium, the battery manufacturing cost is greatly increased, making it unsuitable for industrial production.

[0006] In the aforementioned inventions concerning titanium-based grids, titanium-based grids face problems such as high manufacturing costs, poor bonding between the grid and the active material, and easy failure of the grid. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of high manufacturing cost, poor adhesion of active materials, and easy grid failure in titanium-based grids, and to provide a positive electrode grid with a structure of titanium / intermediate layer / lead. The intermediate layer has good corrosion resistance and conductivity, protects the titanium substrate from sulfuric acid passivation, and has low manufacturing cost. The lead layer can form a corrosion layer with the battery active material, ensuring good adhesion between the titanium-based grid and the active material. This titanium-based grid can be used as a positive electrode current collector in lead-acid batteries, reducing battery weight and increasing battery energy density. Simultaneously, the strong corrosion resistance of this titanium-based grid can improve battery life. In addition, this grid can also be used as a current collector in bipolar lead-acid batteries and other related batteries.

[0008] Therefore, the present invention adopts the following technical solution:

[0009] A titanium-based positive electrode grid for lead-acid batteries is disclosed. The grid is a sandwich structure consisting of a titanium metal substrate, an intermediate layer, and a surface lead metal layer. The titanium metal substrate is a flattened titanium metal or titanium alloy mesh. The intermediate layer is a metal oxide with good conductivity and corrosion resistance. The metal oxide is one of tin-antimony oxide, ruthenium-titanium oxide, ruthenium-titanium oxide, or iridium-tin oxide. The ratio of tin-antimony, ruthenium-titanium, and iridium-tin elements is between 9:1 and 6:4, and the ratio of ruthenium-titanium-tin elements is between 2:7:1 and 1:7:2. The metal oxide content is 10-20 mg / cm³. 2 .

[0010] The intermediate layer is prepared by a thermal decomposition method, the steps of which are as follows:

[0011] 1) Prepare an alcoholic solution of metal ions according to the proportion of metal elements in the metal oxide, wherein the alcohol is one of n-butanol, isobutanol, or n-propanol;

[0012] 2) Add an acid solution to the obtained alcohol solution to prevent the hydrolysis of metal ions and obtain a coating solution. The acid is hydrochloric acid, nitric acid or acetic acid.

[0013] 3) Apply the coating solution obtained in step 2) onto the titanium substrate, dry at 80-150℃ for 5-15 minutes, and then thermally oxidize in air at 400-600℃ for 5-15 minutes.

[0014] 4) Repeat step 3) 10-20 times until the content of metal ions in the coating, calculated based on metal oxides, reaches 10-20 mg / cm³. 2 ;

[0015] 5) Sinter at 400-600℃ for 1-2 hours in air atmosphere to obtain a titanium matrix with a metal oxide intermediate layer.

[0016] Preferably, the thickness of the titanium metal substrate is 0.2-1.0 mm, and the thickness of the lead metal layer is 50-200 μm.

[0017] A method for preparing a titanium-based positive electrode grid for a lead-acid battery includes the following steps:

[0018] (1) Surface pretreatment of titanium metal substrate, wherein the titanium metal substrate is a flattened titanium metal or titanium alloy mesh;

[0019] (2) An intermediate layer is prepared on the surface of a titanium substrate. The intermediate layer is composed of a metal oxide with good conductivity and corrosion resistance. The metal oxide is one of tin-antimony oxide, ruthenium-titanium oxide, ruthenium-titanium oxide, and iridium-tin oxide. The ratio of tin-antimony, ruthenium-titanium, and iridium-tin elements is between 9:1 and 6:4, and the ratio of ruthenium-titanium elements is between 2:7:1 and 1:7:2.

[0020] (3) Electrodeposit a lead metal layer on the titanium-based intermediate layer in step (2).

[0021] Based on the above technical solutions, the present invention can also adopt the following further technical solutions:

[0022] In step (1), the surface pretreatment of the titanium metal substrate includes the steps of water washing, degreasing and acid etching.

[0023] The degreasing step involves cleaning the surface of the titanium metal substrate with a hot 10-30 wt% sodium hydroxide solution; the acid etching step involves cleaning the surface of the titanium metal substrate with a 10-30 wt% hydrochloric acid solution at 80-100℃.

[0024] In step (3), a lead metal layer is prepared on a titanium substrate with a metal oxide interlayer by electrodeposition. The composition of the electrodeposition solution used is 100-200 g / L Pb. 2+ 30-80 g / L free acid, 2-10 g / L gel. Electrodeposition conditions include: room temperature, current density of 10-40 mA / cm². 2 The electrodeposition time is 30-120 minutes.

[0025] In the electrodeposition method described above, Pb 2+ It is added in the form of lead salts, including one or more of lead fluoroborate, lead nitrate, lead methanesulfonate, lead chloride, and lead fluorosilicate. The free acid is one or more of boric acid, fluoroboric acid, fluorosilicic acid, and methanesulfonic acid. The glue is one or more of wood glue, gum arabic, animal glue, and gelatin.

[0026] The beneficial effects of this invention are:

[0027] 1. The lead-acid battery positive electrode grid prepared by the present invention has a composition of titanium / intermediate layer / lead. The preparation process includes substrate processing, intermediate layer preparation, and lead layer deposition. This preparation process is simple, has low pollution and low cost, and is suitable for industrial production.

[0028] 2. The titanium plate grid substrate used in this invention can be as thin as 0.2 mm, while the lead alloy positive plate grid of lead-acid batteries is mostly between 20-40 mm thick. Therefore, the weight of the titanium plate grid is greatly reduced, which can improve the energy density of lead-acid batteries.

[0029] 3. The positive grid of the lead-acid battery of the present invention has strong corrosion resistance, which solves the problem of easy corrosion of the positive grid of lead-acid battery and extends the life of lead-acid battery.

[0030] 4. The titanium plate grid used in this invention is not easily corroded, and the titanium substrate can be reused, thus saving resources, protecting the environment, and reducing manufacturing costs. Attached Figure Description

[0031] Figure 1 This is a surface SEM image of the titanium / tin-antimony oxide interlayer in Example 1.

[0032] Figure 2 This is a surface SEM image of the titanium / tin-antimony oxide interlayer / lead grid in Example 1.

[0033] Figure 3 This is a SEM image of the cross-section of the titanium / tin-antimony oxide interlayer / lead grid and the battery active material in Example 1.

[0034] Figure 4 This is a cycle life diagram of the battery when the titanium / tin-antimony oxide interlayer / lead cathode grid and the commercial cathode lead alloy grid are used as the current collector in Example 1. Detailed Implementation

[0035] Example 1:

[0036] (1) A flattened titanium metal plate with a thickness of 0.2 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 30 wt% sodium hydroxide solution, and then acid etched by heating to 80 ℃ with a 30 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0037] (2) At 10mg / cm 2 The tin-antimony metal oxide content is prepared according to the required metal oxide concentration ratio to prepare an alcohol solution of metal ions. The metal ions are SnCl4·5H2O, SbCl3, and SnCl2. Then, a certain amount of hydrochloric acid is added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 150°C for 10 minutes, and then thermally oxidized at 600°C in air for 15 minutes. This process is repeated 10 times until the coating solution is completely consumed. Finally, the substrate is sintered at 600°C in air for 2 hours to obtain a titanium substrate with a tin-antimony oxide intermediate layer.

[0038] (3) A lead metal layer was prepared on the titanium substrate with the above-mentioned tin-antimony oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 50 μm. The electrodeposition solution composition was 100 g / L Pb. 2+ Pb 2+ The additives were lead fluoroborate, 30 g / L free fluoroborate, and 2 g / L wood glue. The electrodeposition conditions were: temperature 25℃, current density 10 mA / cm². 2 The electrodeposition time was 90 minutes.

[0039] Example 2:

[0040] (1) A flattened titanium alloy mesh with a thickness of 0.2 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 30 wt% sodium hydroxide solution, and then acid etched by heating to 100 ℃ with a 30 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0041] (2) At 20mg / cm 2 The content of the ruthenium titanium oxide intermediate layer is prepared according to the required metal oxide concentration ratio in an alcohol solution containing the corresponding metal ions. The metal ions are sourced from RuCl3·xH2O and tetrabutyl titanate. A certain amount of nitric acid is then added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 80°C for 10 minutes, and then thermally oxidized at 400°C in air for 10 minutes. This process is repeated 20 times until the coating solution is completely consumed. Finally, the substrate is sintered at 400°C in air for 2 hours to obtain a titanium substrate with a ruthenium titanium oxide intermediate layer.

[0042] (3) A lead metal layer was prepared on the titanium substrate with the ruthenium titanium oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 50 μm. The electrodeposition solution composition was 100 g / L Pb. 2+ Pb 2+ The additives were lead fluoroborate, 30 g / L free fluoroborate, and 2 g / L wood glue. The electrodeposition conditions were: temperature 25℃, current density 10 mA / cm². 2 The electrodeposition time is 90 minutes.

[0043] Example 3:

[0044] (1) A flattened titanium alloy mesh with a thickness of 1 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 10 wt% sodium hydroxide solution, and then acid etched by heating to 80 ℃ with a 10 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0045] (2) At 10mg / cm 2The tin-antimony metal oxide content is prepared according to the required metal oxide concentration ratio to prepare an alcohol solution of metal ions. The metal ions are SnCl4·5H2O, SbCl3, and SnCl2. Then, a certain amount of hydrochloric acid is added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 150°C for 5 minutes, and then thermally oxidized at 400°C in air for 10 minutes. This process is repeated 10 times until the coating solution is completely consumed. Finally, the substrate is sintered at 400°C in air for 1 hour to obtain a titanium substrate with a tin-antimony oxide intermediate layer.

[0046] (3) A lead metal layer was prepared on the titanium substrate with the above-mentioned tin-antimony oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 100 μm. The electrodeposition solution composition was 150 g / L Pb. 2+ Pb 2+ Lead fluoroborate and lead nitrate were added, along with 60 g / L free boric acid and 6 g / L animal glue. The electrodeposition conditions were: temperature 25°C, current density 30 mA / cm². 2 The electrodeposition time is 60 minutes.

[0047] Example 4:

[0048] (1) A flattened titanium alloy mesh with a thickness of 1 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 30 wt% sodium hydroxide solution, and then acid etched by heating to 80 ℃ with a 30 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0049] (2) At 20mg / cm 2 The content of the ruthenium titanium tin oxide intermediate layer is prepared according to the required metal oxide concentration ratio in an alcohol solution containing the corresponding metal ions. The metal ions are sourced from RuCl3·xH2O, tetrabutyl titanate, and SnCl4·5H2O. A certain amount of hydrochloric acid is then added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 150°C for 10 minutes, and then thermally oxidized at 600°C for 15 minutes in an air atmosphere. This process is repeated 20 times until the coating solution is completely consumed. Finally, the substrate is sintered at 600°C in an air atmosphere for 2 hours to obtain a titanium substrate with a ruthenium titanium tin oxide intermediate layer.

[0050] (3) A lead metal layer was prepared on the titanium substrate with the above-mentioned ruthenium titanium tin oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 100 μm. The electrodeposition solution composition was 150 g / L Pb. 2+ Pb 2+ Lead fluoroborate and lead nitrate were added, along with 60 g / L free boric acid and 6 g / L animal glue. The electrodeposition conditions were: temperature 25°C, current density 30 mA / cm². 2The electrodeposition time is 60 minutes.

[0051] Example 5:

[0052] (1) A flattened titanium alloy mesh with a thickness of 1 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 30 wt% sodium hydroxide solution, and then acid etched by heating to 90 ℃ with a 30 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0053] (2) At 20mg / cm 2 The content of the iridium-tin oxide intermediate layer is prepared according to the required metal oxide concentration ratio in an alcohol solution containing the corresponding metal ions. The metal ions are derived from chloroiridium acid and SnCl4·5H2O. A certain amount of hydrochloric acid is then added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 80°C for 15 minutes, and then thermally oxidized at 400°C in air for 15 minutes. This process is repeated 20 times until the coating solution is completely consumed. Finally, the substrate is sintered at 400°C in air for 2 hours to obtain a titanium substrate with an iridium-tin oxide intermediate layer.

[0054] (3) A metallic lead layer was prepared on the titanium substrate with the above-mentioned iridium tin oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 200 μm. The solution composition for the electrodeposition method was 200 g / L Pb. 2+ Pb 2+ Lead fluorosilicate and lead nitrate were added, along with 80 g / L free boric acid and fluorosilicic acid, and 10 g / L gelatin. The electrodeposition conditions were: temperature 25℃, current density 40 mA / cm². 2 The electrodeposition time is 100 minutes.

[0055] Example 6:

[0056] (1) A flattened titanium metal plate with a thickness of 1 mm was used as the titanium metal substrate. The titanium metal substrate was pretreated by water washing, degreasing and acid etching. After water washing, it was degreased in a hot 10 wt% sodium hydroxide solution, and then acid etched by heating to 100°C with a 10 wt% hydrochloric acid solution to remove the oxide film on the surface of the titanium substrate.

[0057] (2) At 20mg / cm 2The tin-antimony metal oxide content is prepared according to the required metal oxide concentration ratio to prepare an alcohol solution of metal ions. The metal ions are SnCl4·5H2O, SbCl3, and SnCl2. Then, a certain amount of hydrochloric acid is added to the alcohol solution to obtain a coating solution. The prepared coating solution is brushed onto the treated titanium substrate, dried at 80°C for 15 minutes, and then thermally oxidized at 400°C in air for 15 minutes. This process is repeated 20 times until the coating solution is completely consumed. Finally, the substrate is sintered at 400°C in air for 1 hour to obtain a titanium substrate with a tin-antimony oxide intermediate layer.

[0058] (3) A lead metal layer was prepared on the titanium substrate with the above-mentioned tin-antimony oxide intermediate layer by electrodeposition. The thickness of the deposited lead metal layer was 200 μm. The electrodeposition solution composition was 200 g / L Pb. 2+ Pb 2+ Lead fluorosilicate and lead nitrate were added, along with 80 g / L free boric acid and fluorosilicic acid, and 10 g / L gelatin. The electrodeposition conditions were: temperature 25℃, current density 40 mA / cm². 2 The electrodeposition time is 100 minutes.

[0059] Effect verification

[0060] Figure 3 The image shows a cross-section of the titanium / tin-antimony oxide intermediate layer / lead grid and the battery active material in Example 1. It can be seen from the image that the titanium-based positive electrode grid and the battery active material are tightly bonded together, forming a continuous structure.

[0061] Figure 4 This is a graph showing the cycle life of the battery in Example 1 when using a titanium / tin-antimony oxide interlayer / lead positive electrode grid and a commercial positive lead alloy grid as the current collector. As shown in the graph, the cycle life of the battery based on the titanium / tin-antimony oxide interlayer / lead positive electrode grid is 2.4 times that based on the commercial positive lead alloy grid. This test was conducted at a 2-hour rate of 100% DOD charge / discharge.

Claims

1. A titanium-based positive electrode grid for a lead-acid battery, characterized in that, The grid is a sandwich structure consisting of a titanium metal substrate, an intermediate layer, and a lead metal layer on the surface. The titanium metal substrate is a flattened titanium metal or titanium alloy mesh, and the intermediate layer is a metal oxide with good electrical conductivity and corrosion resistance. The metal oxide is one of tin-antimony oxide, ruthenium-titanium oxide, ruthenium-titanium oxide, or iridium-tin oxide, with the ratio of tin-antimony, ruthenium-titanium, and iridium-tin elements between 9:1 and 6:4, and the ratio of ruthenium-titanium-tin elements between 2:7:1 and 1:7:2; the metal oxide content is 10-20 mg / cm³. 2 A lead metal layer with a thickness of 50-200 μm was prepared on a titanium substrate with a metal oxide interlayer by electrodeposition. The electrodeposition solution used had a composition of 100-200 g / L Pb. 2+ 30-80 g / L free acid, 2-10 g / L glue; electrodeposition conditions include: room temperature, current density of 10-40 mA / cm², and electrodeposition time of 30-120 minutes; the free acid is one or more of boric acid, fluoroboric acid, fluorosilicic acid, and methanesulfonic acid; the glue is one or more of wood glue, peach gum, animal glue, and gelatin.

2. The titanium-based positive electrode grid for a lead-acid battery according to claim 1, characterized in that, The intermediate layer is prepared by a thermal decomposition method, the steps of which are as follows: 1) Prepare an alcoholic solution of metal ions according to the proportion of metal elements in the metal oxide, wherein the alcohol is one of n-butanol, isobutanol, or n-propanol; 2) Add an acid solution to the obtained alcohol solution to prevent the metal ions from hydrolyzing and obtain a coating solution. The acid is hydrochloric acid, nitric acid, or acetic acid. 3) Apply the coating solution obtained in step 2) onto the titanium substrate, dry at 80-150℃ for 5-15 minutes, and then thermally oxidize in air at 400-600℃ for 5-15 minutes. 4) Repeat step 3) 10-20 times until the content of metal ions in the coating, calculated based on metal oxides, reaches 10-20 mg / cm³. 2 ; 5) Sinter at 400-600℃ for 1-2 hours in air atmosphere to obtain a titanium matrix with a metal oxide intermediate layer.

3. The titanium-based positive electrode grid for a lead-acid battery according to claim 1, characterized in that, The thickness of the titanium metal matrix is ​​0.2-1.0 mm.

4. A method for preparing a titanium-based positive electrode grid for a lead-acid battery as described in claim 1, characterized in that, The method includes the following steps: (1) Surface pretreatment of titanium metal substrate, wherein the titanium metal substrate is a flattened titanium metal or titanium alloy mesh; (2) An intermediate layer is prepared on the surface of a titanium substrate by thermal decomposition. The intermediate layer is composed of a metal oxide with good conductivity and corrosion resistance. The metal oxide is one of tin-antimony oxide, ruthenium-titanium oxide, ruthenium-titanium oxide, and iridium-tin oxide. The ratio of tin-antimony, ruthenium-titanium, and iridium-tin elements is between 9:1 and 6:4, and the ratio of ruthenium-titanium-tin elements is between 2:7:1 and 1:7:

2. (3) Electrodeposit a lead metal layer on the titanium-based intermediate layer in step (2), the lead metal layer having a thickness of 50-200 μm; the composition of the electrodeposition solution used is: 100-200 g / L Pb 2+ 30-80 g / L free acid, 2-10 g / L gel; electrodeposition conditions include: room temperature, current density of 10-40 mA / cm². 2 The electrodeposition time is 30-120 minutes; the free acid is one or more of boric acid, fluoroboric acid, fluorosilicic acid, and methanesulfonic acid; the glue is one or more of wood glue, peach gum, animal glue, and gelatin.

5. The method for preparing the titanium-based positive electrode grid for lead-acid batteries according to claim 4, characterized in that, In step (1), the surface pretreatment of the titanium metal substrate includes the steps of water washing, degreasing and acid etching.

6. The method for preparing the titanium-based positive electrode grid for a lead-acid battery according to claim 5, characterized in that, The degreasing step involves cleaning the surface of the titanium metal substrate with a hot 10-30wt% sodium hydroxide solution; the acid etching step involves cleaning the surface of the titanium metal substrate with a 10-30wt% hydrochloric acid solution at 80-100 ℃.

7. The method for preparing the titanium-based positive electrode grid for a lead-acid battery according to claim 4, characterized in that, The steps of the thermal decomposition method are as follows: 1) Prepare an alcoholic solution of metal ions according to the proportion of metal elements in the metal oxide, wherein the alcohol is one of n-butanol, isobutanol, or n-propanol; 2) Add an acid solution to the obtained alcohol solution to obtain a coating solution, wherein the acid is hydrochloric acid, nitric acid or acetic acid; 3) Apply the coating solution obtained in step 2) onto the titanium substrate, dry at 80-150℃ for 5-15 minutes, and then thermally oxidize in air at 400-600℃ for 5-15 minutes. 4) Repeat step 3) 10-20 times until the content of metal ions in the coating, calculated based on metal oxides, reaches 10-20 mg / cm³. 2 ; 5) Sinter at 400-600℃ for 1-2 hours in air atmosphere to obtain a titanium matrix with a metal oxide intermediate layer.

8. The method for preparing the titanium-based positive electrode grid for a lead-acid battery according to claim 4, characterized in that, Pb 2+ It is added in the form of lead salts, which are one or more of lead fluoroborate, lead nitrate, lead methanesulfonate, lead chloride, and lead fluorosilicate.

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