CN110010856B - Conductive polyaniline-modified titanium-based lead dioxide electrode prepared by anodic oxidation co-deposition method - Google Patents

Abstract

A method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, in particular, a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as an anode, and a titanium-based metal oxide electrode containing Pb ²⁺ , aniline and An aqueous solution of alkali metal nitrate is an electrolyte, and a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodic oxidation co-deposition and electrochemical doping activation in an aqueous sulfuric acid solution. The invention can realize the in-situ preparation of modified lead dioxide electrodes by aniline, and simultaneously realize multiple functions such as the construction of the conductive space network of the lead dioxide electrodes, the inhibition of the sulfation of the active materials, and the regulation of the microstructure of the active materials, and can effectively improve the lead dioxide. electrode performance.

Description

Conductive polyaniline-modified titanium-based lead dioxide electrode prepared by anodic oxidation co-deposition method

technical field

A method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, in particular, a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as an anode, and a titanium-based metal oxide electrode containing Pb ²⁺ , aniline and An aqueous solution of alkali metal nitrate is an electrolyte, and a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodic oxidation co-deposition and electrochemical doping activation in an aqueous sulfuric acid solution. The electrode can be used as a positive plate of a lead storage battery, and belongs to the technical field of electrode material preparation and preparation of a positive plate of a lead storage battery.

Background technique

Lead batteries use electrochemical principles to realize the conversion of matter and energy. The characteristics of the electrode plate/electrolyte interface, especially the characteristics of the positive active material/electrolyte interface, are important factors affecting the performance of the battery; the microstructure and morphology of the electrode plate are not only It affects the characteristics of the electrode plate/electrolyte interface, and also affects the utilization of battery active materials, the conductivity of electrodes, and the service life. Therefore, the research and development of new lead-acid battery electrode materials is of great significance.

1. The mechanism of action of positive active material additives in lead batteries

The characteristics of the lead battery electrode plate/electrolyte interface directly affect the performance of the battery. The capacity, energy, power output and cycle life of the positive plate of the lead battery are closely related to the interface reaction, electron transfer, and material (reactant and product) transfer rate, which is the simultaneous transfer process of electrons and materials. It is closely related to the following factors:

(1) Interface reaction

The positive active material (PAM) of the lead battery is mainly composed of lead sulfate (PbSO ₄ ) in the discharge state. The reaction formula of the positive active material during charging and discharging is as follows:

The reaction occurs near the PAM/electrolyte interface. The reaction mechanism is the oxidation/reduction reaction of Pb ²⁺ in the solution. The interface reaction characteristics and the specific surface area of the reaction determine the macroscopic rate of the reaction.

(2) Electron transfer

Electrons are transferred at the PAM/electrolyte interface and transported in the solid-phase PAM. When the electrode is discharged, the Pb ⁴⁺ in the lead dioxide crystal receives the electrons transferred from the external circuit and is reduced to Pb ²⁺ and transferred to the solution ^; when the electrode is charged, the Pb ²⁺ in the solution is oxidized and the electrons are transmitted to the external circuit. The reaction that takes place at the PAM/electrolyte interface inside the PAM must go through the processes of electron migration in the PAM, electron conduction, and electron conduction at the interface between the PAM and the grid to realize the directional movement of the electrons transferred by the electrochemical interface reaction and the electrons of the external circuit.

(3) Mass transfer process

The mass transfer process takes place in the liquid phase. When the electrode is discharged, Pb ⁴⁺ in the lead dioxide crystal gets electrons and is reduced to Pb ²⁺ and transferred to the solution; Pb ²⁺ and HSO ₄ ^- in the solution reach the volume of PbSO ₄ and precipitate out PbSO ₄ solid crystals on the electrode Precipitate. O ^2- in lead dioxide combines with H ⁺ in solution to form water, and PbSO ₄ is continuously deposited as the discharge proceeds; when the electrode is charged, Pb ²⁺ in the solution is oxidized, and H ₂ O molecules in the solution will The H ⁺ ions remain in solution, and the O ^2- and Pb ⁴⁺ enter the lead dioxide lattice. Near the PAM/electrolyte interface, there must be mass transfer of reactants and products from the liquid phase host to the interior of the PAM and internal mass transfer from outside the interface to the electrode surface.

(4) Solid/liquid balance

In the liquid phase near the PAM/electrolyte interface, there is a dissolution equilibrium of solid-phase PbSO ₄ (S) and liquid-phase PbSO ₄ (L), which is closely related to the solubility of PbSO ₄ (S) in sulfuric acid solution, especially PAM The concentration and temperature of SO ₄ ^2- and H ⁺ in the liquid phase near the /electrolyte interface determine the solid/liquid equilibrium characteristics, that is, the solubility of PbSO ₄ (S) in liquid-phase sulfuric acid solution.

(5) Dissolution of solid-phase PbSO ₄ (S) and precipitation of PbSO ₄ (L) in solution

When the Pb ²⁺ in the solution is consumed, the solid phase PbSO ₄ (S) will continue to dissolve, so that the oxidation process of the Pb ²⁺ can continue; when the Pb ²⁺ in the solution is generated, the liquid phase PbSO ₄ (L) crystallizes out. Obviously, the solubility, dissolution rate and crystallization rate of PbSO ₄ have a direct effect on the charge and discharge rate of the electrode.

(6) Liquid phase mass transfer process

The transfer rate of reactants and products in the solution directly affects the reaction rate at the PAM/electrolyte interface by affecting the concentration of the reaction site. Therefore, there must be the problem of liquid phase mass transfer of reactants and products in the liquid phase main body, the liquid phase main body to the reaction zone, and the reaction zone to the PAM/electrolyte interface.

2. Types of positive active material additives for lead batteries

In order to further improve the performance of the lead-acid battery, improve the utilization rate of the positive electrode active material of the lead _- acid battery, improve the oxidation rate of PbSO4 to lead dioxide, and regulate the microstructure of the active material, functional additives are used in the positive electrode active material or in the electrolyte. It is the most effective method. According to the action mechanism of positive active material functional additives, additives can be divided into the following categories:

(1) Additives for building a conductive space network: This type of additive can enable PAM to form a conductive space network before and after chemical formation. The additive should have high conductivity, relatively small density, and properties during charging and discharging. It is stable, has corrosion resistance and certain mechanical strength, and can be closely connected with the positive grid of the lead battery. The additives that meet these requirements mainly include conductive ceramics (such as barium leadate), oxidants with strong oxidizing ability (such as barium leadate) and conductive polymers (such as polyaniline). When dispersed in the PAM lead paste, the conductivity of the positive active material is improved, and a conductive network is formed between the additives, which can effectively improve the formation rate of the electrode plate and the utilization rate of the active material.

(2) Additives that inhibit the sulfation of active substances: In order to increase the reaction rate of lead sulfate oxidation into lead dioxide, the most effective method is to increase the specific surface area of the reaction. During the oxidation of lead sulfate into lead dioxide, the reactants are solid phase PbSO ₄ (S) and liquid phase H ₂ O (L). In order to increase the solid/liquid interface area, only the ratio of PbSO ₄ (S) can be increased. Therefore, an additive that inhibits sulfation of the active material is added to the positive electrode active material. Such additives have the effect of acting as the crystallization center of PbSO ₄ and reducing the solubility of PbSO ₄ . Usually, the solid phase additive is the PbSO ₄ crystallization center; the additives dissolved in the sulfuric acid solution, the sulfate, phosphoric acid and phosphate additives that use the same ion effect use the same ion effect to reduce the solubility of the insoluble electrolyte PbSO ₄ . When the battery is partially charged or fully discharged, the concentration of sulfuric acid is low, and the solubility of lead sulfate is large at this time, which makes lead sulfate easy to recrystallize. The small particle crystals dissolve to form large PbSO ₄ crystals, which in turn accumulate into a dense layer of PbSO ₄ , leading to sulfation of the plates.

(3) Additives for regulating the microstructure of active materials: In order to improve the conversion rate (charge _- discharge rate) of lead dioxide/PbSO4, improve the conversion rate (energy density) of reactants, and obtain a stable microstructure (service life), the Functional additives that regulate the microstructure of active substances are added to PAM, so that PAM has a specific and relatively stable microstructure. PAM is a fixed bed structure (porous electrode), and the added functional additives mainly control the microstructure of PAM, so that the specific surface area of the bed is controlled above 1.0×10 ⁶ m ² /m ³ .

3. The particularity of polyaniline as an additive for positive electrode active material in lead-acid batteries

Conductive polymer is an ideal additive with the above three functions at the same time. Polyaniline can have conductive function after doping and activation, and polyaniline has the characteristics of strong reversibility of electrochemical oxidation/reduction cycle reaction and high chemical stability. Conductive polymer additives that improve the performance of electrode materials are modified and modified materials for electrochemical oxidation reactions, storage batteries, and electrochemical capacitor electrodes. Therefore, the development of in-situ synthesis and electrochemical modification of conductive polymers to prepare polyaniline-modified lead dioxide can effectively improve the performance of lead dioxide electrodes.

4. The main problems existing in the existing technology for preparing polyaniline modified lead dioxide

The traditional technology for preparing polyaniline-modified lead dioxide is mainly to prepare polyaniline by chemical oxidative polymerization of aniline, or to prepare polyaniline by electrochemical polymerization of aniline, and then blend it with lead dioxide and add specific dopants for modification. .

Chinese invention patents [Wang Yaqiong et al., A method for modifying the positive plate of a lead battery with polyaniline (201711158874.X); Wang Yaqiong et al., a method for preparing and modifying the positive plate of a lead battery with polyaniline (201711158870.1)] for the traditional preparation of polyaniline The problems existing in the process and technology of modifying lead dioxide are that aniline is added to the chemical solution during the formation of the positive plate of the lead battery, and the aniline undergoes oxidation reaction at the anode to generate polyaniline-modified lead battery positive plate, and the lead compound on the positive plate is converted into bismuth At the same time as lead oxide, polyaniline can be used to modify the positive grid and positive active material of the battery, thereby improving the performance of the lead battery.

The main problem in the process of adding aniline to the battery formation solution to modify the positive grid and positive active material of the battery is that the polyaniline modification can only be performed on the surface of the positive grid and the positive active material, and it is difficult to realize the construction of a conductive space network at the same time. It has multiple functions such as inhibiting the sulfation of active substances and regulating the microstructure of active substances.

Therefore, in view of the particularity of the preparation and use of lead dioxide, the active material of the positive plate of the lead battery, the preparation of lead dioxide, the preparation of polyaniline, and the modification of lead dioxide by polyaniline are organically combined to realize in-situ polymerization of aniline to modify lead dioxide electrodes. At the same time, it achieves multiple functions such as the construction of the conductive space network of the lead dioxide electrode, the inhibition of the sulfation of the active material, and the regulation of the microstructure of the active material.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method. By adopting the precursor thermal decomposition-anodic oxidation co-deposition-doping activation coupling technology, titanium is obtained as The matrix, the metal oxide as the intermediate layer, the lead dioxide and the polyaniline as the active material are the electrode, and the electrode can be used as the positive plate of the lead storage battery.

The technical solution achieved is: a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, particularly a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor as an anode, and a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor as an anode, The aqueous solution of Pb ²⁺ , aniline and alkali metal nitrate is used as electrolyte, and the anodic oxidation co-deposition technology is used to produce lead dioxide and polyaniline by electrochemical oxidation of Pb ²⁺ and aniline at the electrode/electrolyte interface, respectively. The lead dioxide and polyaniline were co-deposited on the surface of the titanium-based metal oxide electrode to prepare the polyaniline-modified titanium-based lead dioxide electrode, and then the conductive polyaniline was prepared by washing and removing impurities and electrochemical doping and activation in sulfuric acid aqueous solution. The modified titanium-based lead dioxide electrode is characterized in that the steps of electrode preparation are as follows:

(1) Preparation of titanium-based metal oxide electrodes

The preparation of titanium-based metal oxide electrodes includes the following steps:

①Surface treatment: The titanium substrate is mechanically polished, the surface of the alkaline solution is degreasing, the oxalic acid solution is etched, and the surface-treated titanium substrate is obtained;

②Interlayer coating: coating the intermediate layer precursor on the surface-treated titanium substrate;

③ curing: the titanium matrix coated with the intermediate layer precursor is heated and cured in an oven;

④ Roasting: the cured precursor is roasted in the roasting equipment. The coating-curing-baking operations are repeated 5 to 50 times to obtain a titanium-based metal oxide electrode.

(2) Anodized co-deposition

The titanium-based metal oxide electrode prepared in the above step is used as the anode, and the aqueous solution containing Pb ²⁺ , aniline and alkali metal nitrate is used as the electrolyte, and Pb ²⁺ and aniline undergo oxidation reaction at the anode, and co-deposit to obtain polyaniline modified Titanium-based lead dioxide electrode.

(3) Washing and removing impurities

In the washing and impurity removal equipment, the polyaniline-modified lead dioxide electrode obtained in the previous step is subjected to washing and impurity removal treatment to remove nitrate impurities in the electrode.

(4) Doping activation

In an aqueous solution of sulfuric acid, the polyaniline-modified titanium-based lead dioxide electrode obtained in the above step is used as an anode for electrochemical doping and activation to prepare a conductive polyaniline-modified titanium-based lead dioxide electrode.

Further, in the anodic oxidation co-deposition step (2), in the aqueous solution containing Pb ²⁺ , aniline and alkali metal nitrate, the concentration of Pb(NO ₃ ) ₂ is 0.10mol/L～1.0mol/ Between L, the concentration of aniline is between 0.01mol/L～0.80mol/L, the alkali metal nitrate is any combination of LiNO ₃ , NaNO ₃ and KNO ₃ , and the total concentration of alkali metal nitrate is between 0.1mol/L～ Between 1.0mol/L.

Further, in the (2) step anodic oxidation co-deposition step, the anodic oxidation co-deposition method is any method or combination of potentiostatic method, or constant current method, or cyclic voltammetry, or pulse current method , the operating temperature is 10℃～60℃, and the operating current density is 200A/m ² ～2000A/m ² .

Further, in the (4) doping activation step, the concentration of the sulfuric acid aqueous solution is between 0.10 mol/L and 6.0 mol/L, the doping activation adopts an electrochemical oxidation method, and the electrochemical oxidation is a potentiostatic method, or a constant potential method. Any one method or combination of amperometric method, cyclic voltammetry, or pulse amperometric method, the operating temperature is 10°C to 60°C, and the operating current density is 50A/m ² to 1000A/m ² .

Further, the intermediate layer precursor described in the preparation step of the titanium-based metal oxide electrode in the step (1) is composed of the chlorides of Sn and Sb and the salt of any metal in Pb, Y and La. Including citric acid and ethylene glycol, the molar ratio of citric acid and ethylene glycol is (2.0-6.0):1.

Further, in the intermediate layer precursor described in the preparation step of the titanium-based metal oxide electrode in the step (1), the molar ratio of Sn to ethylene glycol is 1:(6.0-24.0), and other metal salts and ethylene glycol The total molar ratio of 1:(6.0～24.0).

Further, in the step (1) of preparing the titanium-based metal oxide electrode, the curing temperature is 60°C to 120°C, and the calcination temperature is 380°C to 620°C.

Further, the geometric shape of the titanium matrix described in the preparation step of the titanium-based metal oxide electrode in the step (1) can be any one of a plate, a wire, a rod, and a drawn mesh.

The technical principle adopted in the present invention:

(1) Taking advantage of the characteristics that both Pb ²⁺ and aniline can undergo electrochemical oxidation reaction on the anode to make their products co-deposited on the anode, the anodic oxidation co-deposition technology is used to electrochemically oxidize Pb ²⁺ and aniline at the electrode/electrolyte interface. Lead dioxide and polyaniline were obtained respectively, and the resulting lead dioxide and polyaniline were co-deposited on the surface of the titanium-based metal oxide electrode to obtain a polyaniline-modified titanium-based lead dioxide electrode. At the same time, lead dioxide could also oxidize aniline to obtain polyaniline. Aniline enables polyaniline to modify lead dioxide electrodes in the three-dimensional space of lead dioxide, thereby realizing the construction of conductive space network, the inhibition of sulfation of active materials, and the regulation of the microstructure of active materials.

(2) Utilize the characteristics of Pb ²⁺ in the anode to generate lead dioxide precipitation by electrochemical oxidation reaction, so that the obtained lead dioxide is deposited on the surface of the titanium-based lead dioxide electrode, and the lead dioxide positive active material of the lead battery is obtained by the formation method. .

(3) Utilize the characteristics of aniline to undergo electrochemical oxidation reaction under neutral medium conditions to generate polyaniline, so that aniline directly undergoes electrochemical oxidation reaction on the electrode to generate polyaniline, and the generated polyaniline is insoluble in the electrolyte and deposited on the electrode. On the electrode, polyaniline modified lead dioxide is realized.

(4) The main reasons for the failure of metal oxide anodes are the dissolution and consumption of the oxide layer, the peeling off and the generation of the passivation film between the active layer and the substrate. The invention designs an electrode with a multi-layer structure, utilizes the characteristics of excellent corrosion resistance of titanium in an aqueous sulfuric acid solution, and adopts titanium as the electrode matrix material; the anti-passivation performance of the electrode is improved through the corrosion-resistant conductive intermediate coating, and the active layer of the electrode is prevented. After shedding and deactivation, the prepared polyaniline-modified lead dioxide not only has high reactivity, but also has long electrode life. In particular, the titanium base metal oxide electrode is used as the positive grid material of the lead battery, which fundamentally solves the problem of corrosion and damage of the existing positive grid, reduces the weight of the lead battery, and improves the energy density of the lead battery. It also creates favorable conditions for the recovery and recycling of electrode materials of lead-acid batteries.

The process technology of the present invention has fully considered the following characteristics:

(1) Utilize the characteristics of lead nitrate and aniline in the neutral medium to undergo electrochemical oxidation reaction to generate lead dioxide and polyaniline respectively, aniline directly undergoes electrochemical oxidation reaction on the electrode to generate polyaniline, while Pb ²⁺ electrochemical reaction The oxidation reaction generates lead dioxide, forming a polyaniline-modified lead dioxide composite material. Because the polyaniline obtained under this reaction condition is an insulating material, the polyaniline can be obtained by doping and activation in an aqueous sulfuric acid solution to obtain a conductive polyaniline, thereby obtaining a polyaniline-modified lead dioxide electrode to improve the performance of the lead dioxide electrode. performance.

(2) Make full use of the characteristics of non-conductive PbSO ₄ to be regenerated by electrochemical oxidation to obtain conductive lead dioxide, so that PbSO ₄ is converted into lead dioxide by oxidation reaction at the anode.

(3) Utilizing the characteristics that lead sulfate anodic oxidation and polyaniline electrochemical doping activation can be carried out simultaneously, lead sulfate is converted into lead dioxide in a sulfuric acid medium, and polyaniline is doped and activated in a sulfuric acid medium to obtain a conductive polymer, Moreover, the transformation of lead sulfate and lead dioxide in sulfuric acid medium, the doping activation of polyaniline in sulfuric acid medium, and the oxidation-reduction of polyaniline all have excellent reversibility. Doping activation of polyaniline is achieved at the same time of electro-polarization.

The beneficial effects of the present invention are embodied in:

(1) Using the anodic oxidation co-deposition technology, Pb ²⁺ and aniline undergo an electrochemical reaction on the anode, and the product is co-deposited on the anode, so that polyaniline can modify the lead dioxide electrode in the three-dimensional space of lead dioxide, and at the same time realize the conductive space It has multiple functions such as network construction, active substance sulfation inhibition, and active substance microstructure regulation.

(2) The polyaniline-modified lead dioxide electrode has good oxidation-reduction reversibility and pseudocapacitance performance. The use as the positive active material of lead batteries can make the positive active material of traditional lead batteries have capacitor characteristics. It can also be used as an electrocatalytic material for oxygen evolution reaction in sulfuric acid solution.

(3) The lead dioxide prepared by anodic electrodeposition of Pb ²⁺ in nitrate aqueous solution has a more balanced proton distribution structure.

(4) The present invention designs an electrode with a multi-layer structure, using the characteristics of titanium with excellent corrosion resistance in aqueous sulfuric acid, and using titanium as the electrode substrate material; The electrode active layer is peeled off and deactivated, and the prepared polyaniline-modified lead dioxide not only has high reactivity, but also has a long electrode life. In particular, the titanium base metal oxide electrode is used as the positive grid material of the lead battery, which fundamentally solves the problem of corrosion and damage of the existing positive grid, reduces the weight of the lead battery, and improves the energy density of the lead battery. It also creates favorable conditions for the recovery and recycling of lead battery electrode materials.

(5) The use of multi-component mixed metal oxide as the intermediate layer can improve the bonding force between the lead dioxide active layer and the substrate, increase the service life of the electrode, and improve the electrochemical performance of the electrode.

Description of drawings

The accompanying drawing is a schematic diagram of the process flow of preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method.

Example 1

As shown in the accompanying drawings, a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, especially a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as an anode, and a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as the anode. The aqueous solution of Pb ²⁺ , aniline and alkali metal nitrate is used as electrolyte, and the anodic oxidation co-deposition technology is used to produce lead dioxide and polyaniline by electrochemical oxidation of Pb ²⁺ and aniline at the electrode/electrolyte interface, respectively. The lead dioxide and polyaniline were co-deposited on the surface of the titanium-based metal oxide electrode to prepare the polyaniline-modified titanium-based lead dioxide electrode, and then the conductive polyaniline was prepared by washing and removing impurities and electrochemical doping and activation in sulfuric acid aqueous solution. The modified titanium-based lead dioxide electrode is characterized in that the steps of electrode preparation are as follows:

(1) Preparation of titanium-based metal oxide electrodes

A titanium-based metal oxide electrode is prepared by using flat titanium as an electrode substrate through surface treatment, intermediate layer coating, curing and roasting. The specific steps are as follows:

①Surface treatment: the titanium substrate is mechanically polished, degreasing with alkaline solution, etched with oxalic acid solution and washed with water to obtain the surface-treated titanium substrate;

②Interlayer coating: Using the coating method, the intermediate layer precursor is coated on the titanium electrode substrate that has been surface-coated and surface-treated in the previous step. The intermediate layer precursor is composed of Sn and Sb chlorides. The precursor also includes Citric acid and ethylene glycol, the molar ratio of citric acid to ethylene glycol is 2.0:1, and the molar ratio of Sn to ethylene glycol in the intermediate layer precursor is 1:6.0;

③Cure: The titanium substrate coated with the intermediate layer precursor is heated and cured in an oven, and the curing temperature is 70°C;

④Baking: the cured precursor is calcined in a calcining device, and the calcination temperature is 430° C.; the coating-curing-calcining operations are repeated 10 times to obtain a titanium-based metal oxide electrode.

(2) Anodized co-deposition

The titanium-based metal oxide electrode prepared in the above step was used as the anode, and an aqueous solution composed of 0.10mol/L Pb(NO ₃ ) ₂ , 0.01mol/L aniline and 0.1 mol/L NaNO ₃ was used as the electrolyte, and the galvanostatic method was used for the electrolyte. The anodic oxidation co-deposition operation, the operating temperature is 10 ℃, the operating current density is 200A/m ² , the Pb ²⁺ and aniline in the solution undergo electrochemical oxidation reaction at the electrode/solution interface, and lead dioxide and polyaniline are co-deposited on the electrode/solution interface, respectively. On the titanium-based metal oxide electrode, the polyaniline-modified titanium-based lead dioxide electrode was prepared by reacting for 10.0 h.

(3) Washing and removing impurities

In the washing and impurity removal equipment, the polyaniline-modified lead dioxide electrode obtained in the previous step is subjected to washing and impurity removal treatment to remove nitrate impurities in the electrode.

(4) Doping activation

In the sulfuric acid aqueous solution, the polyaniline-modified lead dioxide electrode obtained in the above step was used as the anode, and electrochemical doping was activated by the galvanostatic method. The concentration of the sulfuric acid aqueous solution was 1.0 mol/L, the operating temperature was 20 °C, and the operating current density was At 500A/m ² , a conductive polyaniline-modified titanium-based lead dioxide electrode was prepared.

Example 2

As shown in the accompanying drawings, a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, especially a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as an anode, and a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as the anode. The aqueous solution of Pb ²⁺ , aniline and alkali metal nitrate is used as electrolyte, and the anodic oxidation co-deposition technology is used to produce lead dioxide and polyaniline by electrochemical oxidation of Pb ²⁺ and aniline at the electrode/electrolyte interface, respectively. The lead dioxide and polyaniline were co-deposited on the surface of the titanium-based metal oxide electrode to prepare the polyaniline-modified titanium-based lead dioxide electrode, and then the conductive polyaniline was prepared by washing and removing impurities and electrochemical doping and activation in sulfuric acid aqueous solution. The modified titanium-based lead dioxide electrode is characterized in that the steps of electrode preparation are as follows:

(1) Preparation of titanium-based metal oxide electrodes

A titanium-based metal oxide electrode is prepared through surface treatment, intermediate layer coating, curing, and roasting by using wire mesh titanium as the electrode substrate. The specific steps are as follows:

①Surface treatment: The titanium substrate is mechanically polished, the surface of the alkaline solution is degreasing, the oxalic acid solution is etched, and the surface-treated titanium substrate is obtained;

②Interlayer coating: The intermediate layer precursor is coated on the titanium substrate that has been surface-treated in the previous step by the coating method. The intermediate layer precursor is composed of Sn and Sb chlorides and lead chloride. The precursor also contains Including citric acid and ethylene glycol, the molar ratio of citric acid to ethylene glycol is 6.0:1, the molar ratio of Sn to ethylene glycol in the intermediate layer precursor is 1:24.0, and the molar ratio of lead chloride to ethylene glycol is is 1:24.0;

③Cure: The titanium substrate coated with the intermediate layer precursor is heated and cured in an oven, and the curing temperature is 120°C;

④Baking: the cured precursor is calcined in a calcining device, and the calcination temperature is 500° C.; the coating-curing-calcining operations are repeated 20 times to obtain a titanium-based metal oxide electrode.

(2) Anodized co-deposition

The titanium-based metal oxide electrode prepared in the above step was used as the anode, and an aqueous solution composed of 1.0 mol/L Pb(NO ₃ ) ₂ , 0.80 mol/L aniline and 1.0 mol/L NaNO ₃ was used as the electrolyte. The anodic oxidation co-deposition operation, the operating temperature is 60 ℃, the operating current density is 2000A/m ² , the Pb ²⁺ and aniline in the solution undergo electrochemical oxidation reaction at the electrode/solution interface, and lead dioxide and polyaniline are co-deposited on the electrode/solution interface, respectively. On the titanium-based metal oxide electrode, the polyaniline-modified titanium-based lead dioxide electrode was prepared by reacting for 1.0 h.

(3) Washing and removing impurities

In the washing and impurity removal equipment, the polyaniline-modified lead dioxide electrode obtained in the previous step is subjected to washing and impurity removal treatment to remove nitrate impurities in the electrode.

(4) Doping activation

In the sulfuric acid aqueous solution, the polyaniline-modified lead dioxide electrode obtained in the previous step was used as the anode, and electrochemical doping was activated by the galvanostatic method. The concentration of the sulfuric acid aqueous solution was 6.0 mol/L, the operating temperature was 60 °C, and the operating current density was At 1000A/m ² , a conductive polyaniline-modified titanium-based lead dioxide electrode was prepared.

Example 3

As shown in the accompanying drawings, a method for preparing a conductive polyaniline-modified titanium-based lead dioxide electrode by anodizing co-deposition method, especially a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as an anode, and a titanium-based metal oxide electrode prepared by thermal decomposition of a precursor is used as the anode. The aqueous solution of Pb ²⁺ , aniline and alkali metal nitrate is used as electrolyte, and the anodic oxidation co-deposition technology is used to produce lead dioxide and polyaniline by electrochemical oxidation of Pb ²⁺ and aniline at the electrode/electrolyte interface, respectively. The lead dioxide and polyaniline were co-deposited on the surface of the titanium-based metal oxide electrode to prepare the polyaniline-modified titanium-based lead dioxide electrode, and then the conductive polyaniline was prepared by washing and removing impurities and electrochemical doping and activation in sulfuric acid aqueous solution. The modified titanium-based lead dioxide electrode is characterized in that the steps of electrode preparation are as follows:

(1) Preparation of titanium-based metal oxide electrodes

A titanium-based metal oxide electrode is prepared by using round rod-shaped titanium as an electrode substrate through surface treatment, intermediate layer coating, curing and roasting. The specific steps are as follows:

①Surface treatment: The titanium substrate is mechanically polished, the surface of the alkaline solution is degreasing, the oxalic acid solution is etched, and the surface-treated titanium substrate is obtained;

②Interlayer coating: The intermediate layer precursor is coated on the titanium substrate that has been surface-treated in the previous step by the coating method. The intermediate layer precursor is composed of Sn and Sb chlorides and lead chloride. The precursor also contains Including citric acid and ethylene glycol, the molar ratio of citric acid to ethylene glycol is 4.0:1, the molar ratio of Sn to ethylene glycol in the intermediate layer precursor is 1:12.0, and the molar ratio of lead chloride to ethylene glycol is is 1:10.0;

3. Curing: The titanium substrate coated with the intermediate layer precursor is heated and cured in an oven, and the curing temperature is 100 °C;

④Baking: the cured precursor is calcined in a calcining device, and the calcination temperature is 600° C.; the coating-curing-calcining operations are repeated 10 times to obtain a titanium-based metal oxide electrode.

(2) Anodized co-deposition

_The titanium _- based metal _oxide electrode prepared in the above step was used as the _anode . The aqueous solution composed of ₃ is the electrolyte, and the anodic oxidation co-deposition operation is carried out by the galvanostatic method. The operating temperature is 40 °C, and the operating current density is 1000 A/m ² . The Pb ²⁺ and aniline in the solution are electrochemically oxidized at the electrode/solution interface. The reaction produces lead dioxide and polyaniline, which are co-deposited on the titanium-based metal oxide electrode, and react for 24.0 h to obtain the polyaniline-modified titanium-based lead dioxide electrode.

(3) Washing and removing impurities

In the washing and impurity removal equipment, the polyaniline-modified lead dioxide electrode obtained in the previous step is subjected to washing and impurity removal treatment to remove nitrate impurities in the electrode.

(4) Doping activation

In the sulfuric acid aqueous solution, the polyaniline-modified lead dioxide electrode obtained in the above step was used as the anode, and electrochemical doping was activated by the galvanostatic method. The concentration of the sulfuric acid aqueous solution was 1.0 mol/L, the operating temperature was 40 °C, and the operating current density was At 600A/m ² , a conductive polyaniline-modified titanium-based lead dioxide electrode was prepared.

The prepared electrode is used as the positive electrode plate of the lead battery, and the performance of the battery is measured by a comprehensive tester. The cycle life is increased by more than 100%.

In addition to the above-mentioned embodiments, there are still many embodiments of the present invention, and any technical solutions that are equivalent or equivalently replaced are all within the protection scope of the present invention.

Claims (5)

1. A process for preparing the electrically conductive polyaniline modified Ti-base lead dioxide electrode by anode oxidizing codeposition features that the Ti-base metal oxide electrode prepared by thermal decomposition of precursor is used as anode and Pb-contained metal oxide is used as anode ²⁺Aqueous solution of aniline and alkali metal nitrate is used as electrolyte, and an anodic oxidation codeposition technology is adopted to generate Pb at an electrode/electrolyte interface²⁺Respectively obtaining lead dioxide and polyaniline through electrochemical oxidation reaction with aniline, co-depositing the generated lead dioxide and polyaniline on the surface of a titanium-based metal oxide electrode to prepare a polyaniline modified titanium-based lead dioxide electrode, and then washing, removing impurities and electrochemically doping and activating in a sulfuric acid aqueous solution to prepare the conductive polyaniline modified titanium-based lead dioxide electrode, wherein the preparation of the electrode comprises the following steps:

(1) preparing a titanium-based metal oxide electrode: firstly, mechanically polishing a titanium substrate, removing oil on the surface of an alkaline solution, etching by an oxalic acid solution, and washing to obtain a surface-treated titanium substrate; coating the intermediate layer precursor on the titanium substrate subjected to surface treatment; thirdly, heating and curing the titanium substrate coated with the intermediate layer precursor in an oven; fourthly, roasting the solidified precursor in roasting equipment; repeating the coating, curing and roasting operation for 5-50 times to obtain the titanium-based metal oxide electrode;

(2) anodic oxidation codeposition: the titanium-based metal oxide electrode prepared in the previous step is taken as an anode and contains Pb ²⁺Aqueous solution of aniline and alkali metal nitrate as electrolyte, Pb²⁺Carrying out oxidation reaction on the titanium-based lead dioxide electrode and aniline at an anode, and carrying out codeposition to obtain a polyaniline-modified titanium-based lead dioxide electrode; in the electrolyte, Pb (NO)₃)₂The concentration of the alkali metal nitrate is 0.10 mol/L-1.0 mol/L, the concentration of the aniline is 0.01 mol/L-0.80 mol/L, and the alkali metal nitrate is LiNO₃、NaNO₃、KNO₃The total concentration of the alkali metal nitrate is between 0.1mol/L and 1.0 mol/L; the anodic oxidation codeposition method is any one method or combination of a potentiostatic method, a galvanostatic method, a cyclic voltammetry method or a pulse current method, the operating temperature is 10-60 ℃, and the operating current density is 200A/m²～2000A/m²；

(3) Washing to remove impurities: in washing and impurity removing equipment, washing and impurity removing treatment is carried out on the polyaniline-modified lead dioxide electrode obtained in the last step, and nitrate impurities in the electrode are removed;

(4) doping activation: in the aqueous solution with sulfuric acid concentration of 0.10-6.0 mol/L, the titanium-based lead dioxide electrode modified by polyaniline obtained in the previous step is used as an anode for electrochemical doping activation, the electrochemical doping activation adopts any one method or combination of a constant potential method, a constant current method, cyclic voltammetry or a pulse current method scheme, the operating temperature is 10-60 ℃, and the operating current density is 50A/m ²～1000A/m²To prepare the sulfate radical doped conductive polyaniline modified titanium-based lead dioxide electrode.

2. The method for preparing the conductive polyaniline-modified titanium-based lead dioxide electrode by the anodic oxidation codeposition method according to claim 1, which is characterized in that: the intermediate layer precursor in the step (1) of preparing the titanium-based metal oxide electrode consists of chlorides of Sn and Sb and salts of any metal of Pb, Y and La, and further comprises citric acid and ethylene glycol, wherein the molar ratio of the citric acid to the ethylene glycol is (2.0-6.0): 1.

3. The method for preparing the conductive polyaniline-modified titanium-based lead dioxide electrode by the anodic oxidation codeposition method according to claim 1, which is characterized in that: in the intermediate layer precursor prepared in the step (1), the molar ratio of Sn to ethylene glycol is 1 (6.0-24.0), and the total molar ratio of other metal salts to ethylene glycol is 1 (6.0-24.0).

4. The method for preparing the conductive polyaniline-modified titanium-based lead dioxide electrode by the anodic oxidation codeposition method according to claim 1, which is characterized in that: in the step (1), the curing temperature is 60-120 ℃, and the roasting temperature is 380-620 ℃.

5. The method for preparing the conductive polyaniline-modified titanium-based lead dioxide electrode by the anodic oxidation codeposition method according to claim 1, which is characterized in that: the geometry of the titanium substrate in the step (1) of preparing the titanium-based metal oxide electrode can be any one of a plate, a wire, a rod and a net.

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