Pyrrolo-pyrrole self-polymerization positive electrode and preparation method and application thereof

Abstract

The invention discloses a pyrrolo-pyrrole self-polymerization positive electrode as well as a preparation method and application of the pyrrolo-pyrrole self-polymerization positive electrode. Relates to the field of cathode materials. The positive electrode comprises a positive electrode material layer, and the positive electrode material layer comprises a polymer generated by in-situ electropolymerization reaction of an active material; the active material comprises a compound a, the structural formula of the compound a is # imgabs0 #, and R is a group containing an aromatic ring or a heteroaromatic ring. The first-circle charge-discharge specific capacity of the prepared positive electrode can reach 190mAh / g in a lithium battery assembly test, and the positive electrode has high specific capacity and good cycling stability and has good application prospects in the field of lithium battery positive electrode materials.

Description

Technical Field

[0001] The present invention relates to the technical field of positive electrode materials, and in particular to a pyrrolopyrrole self-polymerizing positive electrode and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of the global electric new energy vehicle industry and the large-scale application of renewable energy, the demand for energy storage technologies has continued to grow. Batteries with high energy density, long cycle life, high reliability, and stability have become a key requirement for electric vehicles, power storage systems, and mobile devices. Among the many battery technologies, lithium-ion batteries (LIBs) have become the most mainstream due to their significantly superior performance, particularly high energy density and excellent cycle performance.

[0003] The advantage of lithium batteries lies in their high energy density, making them relatively lightweight and compact, enabling longer battery life or endurance in applications like electric vehicles. Furthermore, lithium-ion batteries maintain excellent cycle performance over long charge and discharge cycles without significant memory effects, which is crucial for mobile devices and electric vehicles, significantly extending their lifespan. More importantly, lithium batteries are environmentally friendly, with a lower environmental impact than traditional batteries like lead-acid batteries, aligning with the current global trend towards green development.

[0004] However, the cathode material in lithium batteries has a crucial impact on battery performance. The electrochemical performance and production cost of lithium batteries are largely determined by the composition of their cathode materials. Currently, the cathode materials used in commercial lithium batteries are primarily inorganic metal oxides, such as lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), and lithium iron phosphate (LiFePO4). Lithium cobalt oxide is widely used in portable electronic devices, while lithium manganese oxide and lithium iron phosphate are even more widely used in electric vehicles. Although these inorganic metal oxides have high electrochemical performance, they have several significant drawbacks. First, metal materials are mostly limited resources, and some metals (such as cobalt) have high costs and unstable supply. Second, metal oxide resources are non-renewable, making it difficult to meet the needs of future large-scale industrialization, and their production process may cause certain environmental pollution. These factors pose challenges to the sustainable development of current lithium battery cathode materials.

[0005] In this context, organic electrode materials have gradually attracted widespread attention as a potential alternative. Organic electrode materials have many advantages that traditional inorganic materials do not have, especially in terms of sustainability, environmental protection and cost. Organic materials are mainly composed of elements with abundant reserves in the earth's crust, such as carbon (C), hydrogen (H) and oxygen (O). These elements are not only abundant in resources and low in cost, but also have less burden on the environment during use. Therefore, organic electrode materials have the potential advantages of low cost and environmental friendliness, which is of great significance for realizing green battery technology and promoting the sustainable development of the industry.

[0006] In addition, organic materials have light weight and good mechanical properties, and their flexibility makes them more competitive in certain specific applications. For example, in wearable devices and flexible electronic products, organic electrode materials can provide these lightweight and flexible devices with better battery performance and durability. At the same time, the structure of organic materials can be flexibly adjusted through molecular design, allowing them to be optimized according to different electrochemical performance requirements. For example, by adjusting the length of the molecular chain, introducing different functional groups, or changing the molecular configuration, the conductivity, stability, and cycle performance of the material can be effectively improved.

[0007] These advantages make organic electrode materials an important direction for the future development of positive electrode materials for lithium-ion batteries. By developing suitable organic electrode materials, it is expected to make important progress in reducing battery costs, improving battery performance and increasing battery sustainability. However, despite the huge potential of organic electrode materials, current research still faces some challenges, especially in terms of electrochemical performance. The energy density and cycle stability of organic electrode materials still have a certain gap compared to traditional inorganic metal oxides, which makes it difficult for them to compete with inorganic materials in practical applications.

[0008] First, the electrochemical performance of organic electrode materials is often limited by their molecular structure and charge transport capabilities. Although organic materials can be optimized through molecular design, existing organic materials still have deficiencies in energy density and electrical conductivity. In particular, during the battery charging and discharging process, organic materials may undergo structural changes, resulting in capacity degradation or shortened cycle life. In addition, the stability and conductivity of organic materials also need to be further improved. To address these issues, researchers are exploring different organic material systems, such as polymers, conjugated molecules, and small molecule organic compounds, in order to find more advantageous electrode materials.

[0009] Secondly, the synthesis process and stability of organic electrode materials have also become research difficulties. Compared with inorganic materials, the synthesis process of organic electrode materials is more complex, and instability may occur during the preparation process. Especially in the process of large-scale production, the stability and consistency of organic materials are key. To meet the needs of industrialization, developing more efficient, economical and environmentally friendly preparation processes and improving the quality and consistency of materials are key to promoting the application of organic electrode materials.

[0010] Based on this, there is an urgent need to develop a more stable organic electrode material with better performance. Summary of the Invention

[0011] The object of the present invention is to provide a positive electrode material with high specific capacity and good cycle stability.

[0012] A first aspect of the present invention is:

[0013] A positive electrode is provided.

[0014] The second aspect of the present invention is:

[0015] Provided is a method for preparing a positive electrode.

[0016] The third aspect of the present invention is:

[0017] Application of the positive electrode.

[0018] The present invention also provides a battery.

[0019] Specifically, the technical solution adopted according to the first aspect of the present invention is:

[0020] A positive electrode comprises a positive electrode material layer, wherein the positive electrode material layer comprises a polymer generated by an in-situ electropolymerization reaction of an active material; the active material comprises compound a, and the structural formula of compound a is:

[0021]

[0022] Here, R is a group containing an aromatic ring or a heteroaromatic ring.

[0023] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0024] The positive electrode prepared by the present invention can achieve a first-cycle charge and discharge specific capacity of 190 mAh / g in a lithium battery assembly test, has high specific capacity and good cycle stability, and has good application prospects in the field of lithium battery positive electrode materials.

[0025] Specifically:

[0026] Compound A has a pyrrolopyrrole molecular skeleton, which forms a rigid planar structure after in-situ electropolymerization, featuring a highly conjugated π electron delocalization system. This structure provides a fast electron migration path, significantly improving the intrinsic conductivity of the electrode material, thereby reducing polarization and increasing charge and discharge rates and specific capacity. The rigid conjugated planar structure also effectively resists volume deformation during lithium-ion insertion and extraction, reducing mechanical stress damage to the material particles and thus maintaining the integrity of the electrode structure.

[0027] Due to their strong electronegativity, the nitrogen atoms (pyrrole ring) and oxygen atoms in the compound a molecule can coordinate with lithium ions in the battery to form stable lithium ion adsorption sites, thereby improving the lithium ion insertion efficiency and the reversible capacity of the material.

[0028] According to one embodiment of the present invention, R is selected from at least one of a thienyl group, a furyl group, and a benzene ring. Preferably, R is selected from a thienyl group. Compound a containing a thiophene structure is beneficial for improving the stability of the polymer, thereby improving the stability of the positive electrode.

[0029] According to one embodiment of the present invention, the components of the positive electrode material layer further include a conductive agent and a binder, and the mass ratio of the compound a, the conductive agent and the binder is 2-8:2-8:1, preferably 2-3:6-8:1.

[0030] According to one embodiment of the present invention, the mass percentage of compound a in the components of the positive electrode material layer is ≤80%. The greater the mass percentage of compound a in the positive electrode material, the higher its utilization rate as an active substance, thereby improving the capacity of the battery. However, compound a is an organic material, and organic materials generally have a higher solubility, and higher solubility often leads to a decrease in cycle performance. Therefore, the content of compound a in the positive electrode material needs to be maintained in a balanced state. Based on this, the mass percentage of compound a in the positive electrode material should be ≤80%.

[0031] According to one embodiment of the present invention, the mass percentage of the compound a in the components of the positive electrode material layer is 30%-60%.

[0032] According to one embodiment of the present invention, the mass percentage of the compound a in the components of the positive electrode material layer is 40%-60%.

[0033] According to one embodiment of the present invention, the mass percentage of the compound a in the components of the positive electrode material layer is 50%-60%.

[0034] According to one embodiment of the present invention, the mass percentage of the compound a in the components of the positive electrode material layer is 60%-70%.

[0035] According to one embodiment of the present invention, the mass percentage of the compound a in the components of the positive electrode material layer is 70%-80%.

[0036] According to one embodiment of the present invention, the conductive agent includes at least one of conductive carbon black, acetylene black, graphene and carbon nanotubes.

[0037] According to one embodiment of the present invention, the binder includes at least one of polyvinylidene fluoride, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, hydroxypropyl methylcellulose, polyvinyl alcohol and polyimide.

[0038] Specifically, the technical solution adopted according to the second aspect of the present invention is:

[0039] A method for preparing the positive electrode comprises the following steps:

[0040] The active material, the negative electrode, the separator and the electrolyte are assembled into a battery, and the active material is subjected to an in-situ electropolymerization reaction to obtain the positive electrode.

[0041] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0042] This invention uses an in-situ electropolymerization process to react the active material directly within the battery's microenvironment, formed by the negative electrode, electrolyte, and separator. The resulting polymer cathode material forms a three-dimensional, continuous conductive network that naturally adheres to the electrode interface. Unlike traditional processes, where the active material must be pre-synthesized and then mixed and coated with a binder and conductive agent, this process directly synthesizes the material through in-situ polymerization within the battery. The resulting polymer skeleton is capable of adapting to the internal stress distribution of the battery, and its rigid conjugated planar structure effectively resists deformation during cycling, thereby maintaining the integrity of the electrode structure and ensuring the battery's high cycling stability.

[0043] According to one embodiment of the present invention, the voltage of the in-situ electropolymerization reaction is 1.0-3.8V.

[0044] According to one embodiment of the present invention, the in-situ electropolymerization reaction is to first discharge to 1.0V-1.5V and then charge to above 3.5V, with the discharge and charge steps repeated at least twice. The discharge voltage is controlled between 1.0V and 1.5V. During the low-voltage discharge stage, lithium ions preferentially embed into the molecular skeleton of the active material, triggering the rearrangement of intermolecular hydrogen bonds or π-π stacking, forming a pre-organized structure that is conducive to subsequent polymerization. This process can be regarded as "molecular activation", providing an ordered reaction template for subsequent electropolymerization. The discharge voltage range of 1.0-1.5V avoids excessive reduction of active material molecules at excessively high reduction potentials, protects the molecular main chain structure, and ensures the integrity of subsequent polymerization reactions. High voltage (>3.5V) provides sufficient energy to promote the formation of long-chain conjugated polymers through oxidative coupling reactions of active material monomers, generating a three-dimensional conductive network in situ, enhancing the overall conductivity of the material and expanding the lithium ion transmission path. During the charging process, the active material molecules are oriented under the drive of the electric field, forming a stable layered structure, increasing the specific surface area and lithium ion diffusion channels, thereby improving reaction kinetics and reversible capacity.

[0045] In addition, the in-situ electropolymerization process of the present invention optimizes the micromorphology of the positive electrode material, forming a stable layered structure while forming uniform pores, avoiding the formation of honeycomb or irregular shaped structures, thereby buffering the volume changes during charging and discharging, reducing mechanical damage, and providing a guarantee for the cycle stability of the lithium battery.

[0046] According to one embodiment of the present invention, the in-situ electropolymerization reaction comprises the following steps: first discharging to 1.0V-1.5V, and then charging to above 3.8V.

[0047] According to one embodiment of the present invention, the in-situ electropolymerization reaction comprises the following steps: first discharging to 1.0V-1.5V, and then charging to 3.8V-4.5V.

[0048] A battery comprises the positive electrode.

[0049] According to one embodiment of the present invention, the battery further comprises a negative electrode, an electrolyte and a separator.

[0050] A method for preparing a battery, comprising the following steps:

[0051] Active materials, conductive agents and adhesives are mixed and pressed to obtain pole pieces, which are then vacuum dried and assembled into a battery with a negative electrode, a separator and an electrolyte, and the active materials are subjected to in-situ electropolymerization reaction to obtain the battery.

[0052] According to one embodiment of the present invention, the vacuum drying temperature is 90-100°C.

[0053] According to one embodiment of the present invention, the vacuum drying time is 10-12 hours.

[0054] According to one embodiment of the present invention, the method for preparing a battery further includes the following steps: mixing the active material, the conductive agent and the binder, and grinding and stirring for 30-60 minutes.

[0055] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0057] Figure 1 Flowchart of the positive electrode preparation method in Example 1-2.

[0058] Figure 2 This is the SEM image of the positive electrode material in Example 1.

[0059] Figure 3 This is the SEM image of the positive electrode material in the comparative example.

[0060] Figure 4 This is the infrared spectrum of the finished electrode of Example 1-2.

[0061] Figure 5 This is a voltage-specific capacity curve of the battery in Example 1.

[0062] Figure 6 This is a charge and discharge cycle curve diagram of the battery in Example 1.

[0063] Figure 7 This is a voltage-specific capacity curve of the battery in Example 2.

[0064] Figure 8 This is a charge and discharge cycle curve of a comparative battery.

[0065] Figure 9 This is a rate test diagram of the battery in Example 1. DETAILED DESCRIPTION

[0066] The terms "preferred," "more preferred," and the like, used herein refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present invention.

[0067] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0068] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of the present invention.

[0069] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0070] Example 1

[0071] A positive electrode comprises a positive electrode material layer, wherein the positive electrode material layer comprises a polymer generated by an in-situ electropolymerization reaction of an active material; the active material comprises compound a, which was purchased from Suzhou Nakai Technology Co., Ltd. with the product number 850583-75-4. The structural formula of compound a is:

[0072]

[0073] A method for preparing the above-mentioned positive electrode, the flow chart is as follows Figure 1 As shown, Figure 1 wherein Th represents a thiophene group and DPP represents a pyrrolopyrrole, comprising the following steps:

[0074] 3 mg of compound a, 6 mg of conductive carbon black, and 1 mg of polyvinylidene fluoride were added to a graphite mortar and ground and stirred for 30 minutes to fully mix the three materials. The mixed powder was placed in a tablet press to obtain a finished electrode. The finished electrode was placed in a vacuum oven and dried at 90°C for 10 hours.

[0075] In an argon glove box, the dried finished electrode, glass fiber diaphragm, electrolyte, lithium sheet, and gasket shrapnel are assembled into the battery in sequence and pressure-sealed;

[0076] The encapsulated battery was connected to the blue electric system. After standing for 8 hours, it was discharged to 1.5V and then charged to 4.5V. The cycle was repeated twice to complete the in-situ electropolymerization and obtain the positive electrode. The SEM image of the positive electrode material loaded on the positive electrode is shown in Figure 2. Figure 2 shown.

[0077] A battery comprises a negative electrode, an electrolyte, a separator and the positive electrode prepared above.

[0078] Example 2

[0079] A positive electrode comprising a positive electrode material layer, wherein the positive electrode material layer comprises a polymer generated by an in-situ electropolymerization reaction of an active material; the active material comprises compound a, which was purchased from Suzhou Nakai Technology Co., Ltd. with the product number IN1800-2g. The structural formula of compound a is:

[0080]

[0081] A method for preparing the above-mentioned positive electrode, the flow chart is as follows Figure 1 As shown, the following steps are included:

[0082] 3 mg of compound a, 6 mg of conductive carbon black, and 1 mg of polyvinylidene fluoride were added to a graphite mortar and ground and stirred for 30 minutes to fully mix the three materials. The mixed powder was placed in a tablet press to obtain a finished electrode. The finished electrode was placed in a vacuum oven and dried at 90°C for 10 hours.

[0083] In an argon glove box, the dried finished electrode, glass fiber diaphragm, electrolyte, lithium sheet, and gasket shrapnel are assembled into the battery in sequence and pressure-sealed;

[0084] The packaged battery was connected to the blue-electric system. After standing for 8 hours, it was first discharged to 1.5V and then charged to 4.5V. This cycle was repeated twice to complete in-situ electropolymerization and obtain the positive electrode.

[0085] A battery comprises a negative electrode, an electrolyte, a separator and the positive electrode prepared above.

[0086] Comparative Example

[0087] The difference between the comparative example and Example 1 is that in the comparative example, the parameters of the in-situ electropolymerization are different from those in Example 1. In the comparative example, the battery is first discharged to 1.5V and then charged to 3.5V.

[0088] Specifically:

[0089] A positive electrode comprises a positive electrode material layer, wherein the positive electrode material layer comprises a polymer generated by an in-situ electropolymerization reaction of an active material; the active material comprises compound a, which was purchased from Suzhou Nakai Technology Co., Ltd. with the product number 850583-75-4. The structural formula of compound a is:

[0090]

[0091] A method for preparing the above-mentioned positive electrode comprises the following steps:

[0092] 3 mg of compound a, 6 mg of conductive carbon black, and 1 mg of polyvinylidene fluoride were added to a graphite mortar and ground and stirred for 30 minutes to fully mix the three materials. The mixed powder was placed in a tablet press to obtain a finished electrode. The finished electrode was placed in a vacuum oven and dried at 90°C for 10 hours.

[0093] In an argon glove box, the dried finished electrode, glass fiber diaphragm, electrolyte, lithium sheet, and gasket shrapnel are assembled into the battery in sequence and pressure-sealed;

[0094] The packaged battery was connected to the blue electric system. After standing for 8 hours, it was discharged to 1.5V and then charged to 3.5V. The cycle was repeated twice to obtain a positive electrode. The SEM image of the positive electrode material loaded on the positive electrode is shown in the figure. Figure 3 shown.

[0095] A battery comprises a negative electrode, an electrolyte, a separator and the positive electrode prepared above.

[0096] Performance testing:

[0097] Take the finished electrode of Example 1-2 and conduct infrared spectrum test. The test results are as follows: Figure 4 As shown, Figure 4 In the equation, Wavenumbers is the wave number, Transmittance is the transmittance, and Figure 4 It can be seen that compound a was successfully loaded onto the finished electrode.

[0098] Take the lithium battery prepared in Example 1 and perform a charge and discharge curve test on the lithium battery in the blue battery test system to obtain the voltage-specific capacity curve of the battery ( Figure 5 ). Figure 5 In the equation, specific capacity is specific capacity, voltage is voltage, Figure 5 It can be seen that the lithium battery based on the positive electrode material of the present invention can achieve a first-cycle charge and discharge capacity of 190 mAh / g at a current of 20 mA / g, has high specific capacity and good cycle stability, and has good application prospects in the field of lithium battery positive electrode materials.

[0099] Take the lithium battery prepared in Example 1 and perform the charge and discharge cycle curve test on the blue battery test system. The test results are as follows: Figure 6 As shown, Figure 6In the equation, Cycle number is the number of cycles, specific capacity is the specific capacity, Change Capacity is the charge capacity, Discharger Capacity is the discharge capacity, and Coulombic efficiency is the Coulombic efficiency. Figure 6 It can be seen that the lithium battery of Example 1 still shows good cycle performance after 100 cycles, which shows that it has good application prospects in the field of lithium battery positive electrode materials.

[0100] Take the lithium battery prepared in Example 2 and perform a charge and discharge curve test on the lithium battery in the blue battery test system to obtain the voltage-specific capacity curve of the battery ( Figure 7 ). Figure 7 In the equation, specific capacity is specific capacity, voltage is voltage, Figure 7 It can be seen that the lithium battery based on the positive electrode material of the present invention can achieve a first-cycle charge and discharge capacity of 380 mAh / g at a current of 20 mA / g, has high specific capacity and good cycle stability, and has good application prospects in the field of lithium battery positive electrode materials.

[0101] The lithium battery prepared in the comparative example was tested for charge and discharge cycle curve in the blue battery test system. The test results are as follows: Figure 8 As shown, Figure 8 In the equation, Cycle number is the number of cycles, and specific capacity is the specific capacity. Figure 8 It can be seen that in the comparative example, because the voltage was only charged to 3.5V, the active material polymerization was poor and there was almost no self-polymerization, which made the battery perform poorly in terms of charge and discharge capacity. Although the Coulombic efficiency was relatively stable, the overall battery performance was still greatly limited and could not meet the use requirements of higher-performance batteries. In the figure, the green curve (charge capacity (Change Capacity)) overlaps with the blue curve (discharge capacity (Discharger Capacity)). The overall curve fluctuates more violently and the value is low, indicating that during the charging process, the battery can store unstable and relatively small amounts of electricity.

[0102] The lithium battery prepared in Example 1 was tested at different current densities in a blue battery test system. The test results are as follows: Figure 9 , Figure 9 Where Cycle number is the number of cycles, specific capacity is the specific capacity, Figure 9It can be seen that the Coulombic efficiency remains at a relatively high level (mostly above 90%) throughout the entire cycle process, and the fluctuation of the Coulombic efficiency at different rates is relatively small. This indicates that the battery has good reversibility during the charge and discharge process and high charge utilization efficiency. In addition, with the increase in the number of cycles, the charge capacity (green) and discharge capacity (blue) at different rates show a gradual downward trend. At high rates (such as 500mA / g), the capacity decreases relatively significantly and quickly; while at low rates (such as 20mA / g), the capacity decreases relatively slowly.

[0103] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A positive electrode, characterized in that: The positive electrode material layer includes a polymer generated by an in-situ electropolymerization reaction of an active material; the active material includes compound a, and the structural formula of compound a is: Here, R is a group containing an aromatic ring or a heteroaromatic ring.

2. A positive electrode according to claim 1, characterized in that: The R is selected from at least one of a thienyl group, a furyl group and a benzene ring.

3. A positive electrode according to claim 1, characterized in that: The components of the positive electrode material layer further include a conductive agent and a binder, and the mass ratio of the compound a, the conductive agent and the binder is 2-8:2-8:

1.

4. A positive electrode according to claim 1, characterized in that: The mass percentage of the compound a in the components of the positive electrode material layer is ≤80%.

5. A positive electrode according to claim 3, characterized in that: The conductive agent includes at least one of conductive carbon black, acetylene black, graphene and carbon nanotubes.

6. A positive electrode according to claim 3, characterized in that: The binder includes at least one of polyvinylidene fluoride, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, hydroxypropyl methyl cellulose, polyvinyl alcohol and polyimide.

7. A method for preparing the positive electrode according to any one of claims 1 to 6, characterized in that: The following steps are involved: The active material, the negative electrode, the separator and the electrolyte are assembled into a battery, and the active material is subjected to an in-situ electropolymerization reaction to obtain the positive electrode.

8. The method according to claim 7, wherein: The voltage of the in-situ electropolymerization reaction is 1.0-3.8V.

9. The method according to claim 8, characterized in that: The in-situ electropolymerization reaction comprises the following steps: first discharging to 1.0V-1.5V, and then charging to above 3.5V.

10. A battery, characterized in that: The positive electrode comprises the positive electrode according to any one of claims 1 to 6.

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