Highly stable organic polymer electrodes, their preparation methods, and batteries using them

Abstract

This invention relates to the field of energy storage battery electrode technology, and discloses a highly stable organic polymer electrode, its preparation method, and a battery using the same. The electrode is composed of a bisvioletin side-chain functionalized polyaryl ether compound and nitrogen-doped carbon nanotubes. The organic polymer electrode of this invention, containing a bisvioletin side-chain functionalized polyaryl ether compound, has advantages such as high viologen content, high theoretical specific capacity, high thermal stability, and good flexibility. Sodium-ion batteries using this highly stable organic polymer electrode also exhibit high charge-discharge capacity and excellent cycle stability.

Description

Technical Field

[0001] This invention relates to the field of energy storage battery electrode technology, and more particularly to a highly stable organic polymer electrode, its preparation method, and batteries using the same. Background Technology

[0002] Electrochemical energy storage technology is crucial for driving the development of next-generation electric vehicles and smart grids. Among existing electrochemical energy storage technologies, sodium-ion batteries have advantages such as abundant raw material reserves, low price, high energy density, and good safety, making them a promising technology with enormous potential.

[0003] Developing advanced electrode materials is key to improving the performance of sodium-ion batteries. Current sodium-ion batteries use inorganic electrodes, which suffer from poor structural stability, high cost, low theoretical yield, and significant environmental pollution. In contrast, organic electrode materials offer advantages such as structural diversity, sustainability, and high safety, attracting increasing attention and becoming a vital force in promoting green energy.

[0004] In the prior art, organic electrodes prepared from organic sulfides, pteridine derivatives, nitro oxygen free radical compounds and carbonyl compounds have good electrochemical reversibility and charge storage mechanism. However, the materials of organic electrodes are easy to dissolve in the battery electrolyte, which easily leads to the defect of rapid capacity decay during cycling, which seriously limits the promotion of organic electrode materials in the prior art. Summary of the Invention

[0005] To address the aforementioned problems, the primary objective of this invention is to propose a highly stable organic polymer electrode. The polyarylene ether compound in the main chain reduces the effect of the divioletin side chain in the electrolyte. Batteries using this highly stable organic polymer electrode also exhibit higher charge-discharge capacity and excellent cycle stability.

[0006] The second objective of this invention is to provide a simple method for preparing the aforementioned highly stable organic polymer electrode, suitable for large-scale production.

[0007] A third objective of this invention is to provide a sodium-ion battery using an organic polymer electrode with the above-mentioned stability, so as to improve the charge / discharge capacity and cycle stability of the battery.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] A highly stable organic polymer electrode is composed of a bisvioletin side-chain functionalized polyarylene ether compound and nitrogen-doped carbon nanotubes.

[0010] The chemical structure of the bisvioletin side-chain functionalized polyaryl ether compound is as follows:

[0011] Where n is an integer between 20 and 300, and -R is -H or

[0012] Furthermore, this invention proposes a method for preparing a highly stable organic polymer electrode, which includes the following steps:

[0013] S1) 3,3',5,5'-tetramethylbiphenyl, 4,4'-difluorobenzophenone and anhydrous potassium carbonate are added to N,N-dimethylacetamide and stirred to mix. Then toluene is added, and under inert gas protection, the temperature is raised to 140-150℃ and reacted for 1-5 hours. The water generated in the reaction is removed by reflux of toluene, and then the toluene is distilled off. The temperature is then raised to 150-170℃ and reacted for 12-24 hours. After cooling to room temperature, the mixture is poured into deionized water to precipitate the first precipitate. The first precipitate is collected by filtration and dried in a vacuum oven at 80-100℃ for 24 hours to obtain the polyarylene ether compound.

[0014] S2) The polyarylene ether compound and N-bromosuccinimide are mixed and dissolved in 1,2-dichloroethane. Benzoyl peroxide is used as an initiator. The reaction is carried out at 60-150°C for 6-60 hours under inert gas protection. After cooling to room temperature, the mixture is poured into methanol to precipitate a second precipitate. The second precipitate is collected by filtration and dried in a vacuum oven at 80-100°C for 24 hours to obtain the bromomethylated polyarylene ether compound.

[0015] S3) The bromomethylated polyarylene ether compound and 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound are mixed and dissolved in a polar aprotic solvent. Under inert gas protection and at 60-120°C, the mixture is reacted for 24-72 hours. The reaction solution is then poured into deionized water, and excess ammonium hexafluorophosphate is added to precipitate a third precipitate. The mixture is filtered, and the third precipitate is dried in a vacuum oven at 80-100°C for 24 hours. The dried third precipitate is then dissolved in a polar aprotic solvent, and iodomethane is added. Under inert gas protection and at 40-60°C, the mixture is reacted for 12-36 hours. The solution containing iodomethane is then poured into deionized water, and excess ammonium hexafluorophosphate is added to precipitate a first solid. The mixture is filtered, and the first solid is washed with methanol and deionized water. The washed first solid is then dried in a vacuum oven at 80-100°C for 24 hours to obtain the bisvioletin side-chain functionalized polyarylene ether compound.

[0016] S4) The bisvioletin side-chain functionalized polyaryl ether compound and nitrogen-doped carbon nanotubes are dispersed in N-methylpyrrolidone to form a slurry. After ultrasonic treatment for 1-3 hours, the slurry is uniformly coated onto aluminum foil and dried in a forced-air oven at 50-150°C for 1-5 hours, and then dried in a vacuum oven at 50-150°C for 12-36 hours to obtain the highly stable organic polymer electrode.

[0017] Preferably, in step S1), the molar ratio of 3,3',5,5'-tetramethylbiphenyl, 4,4'-difluorobenzophenone and anhydrous potassium carbonate is 1:1:(3-6).

[0018] Preferably, in step S1), the volume ratio of N,N-dimethylacetamide to toluene is 1:(0.1-1); the volume of N,N-dimethylacetamide corresponding to each mole of 3,3',5,5'-tetramethylbiphenyl is 1-6 mL.

[0019] Preferably, in step S2), the molar ratio of the polyarylene ether compound, N-bromosuccinimide, and benzoyl peroxide is 1:(2-8):(0.1-0.02); and the volume of 1,2-dichloroethane corresponding to each gram of polyarylene ether compound is 10-100 mL.

[0020] Preferably, in step S3), the molar ratio of the bromomethylated polyarylene ether compound, the 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound to iodomethane is 1:(2-12):(4-20); and the volume of polar aprotic solvent corresponding to each gram of bromomethylated polyarylene ether compound is 10-100 mL.

[0021] Preferably, in step S3), the polar aprotic solvent is any one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0022] Preferably, in step S4), the mass ratio of the bisvioletin side-chain functionalized polyarylene ether compound to the nitrogen-doped carbon nanotube is 1:(0.1-1); the amount of N-methylpyrrolidone corresponding to each gram of bisvioletin side-chain functionalized polyarylene ether compound is 3-20 mL.

[0023] Furthermore, the present invention also proposes a sodium-ion battery, wherein the positive electrode is prepared using the above-described method for preparing a highly stable organic polymer electrode.

[0024] The beneficial effects of the above-mentioned technical solution of the present invention are as follows: The organic polymer electrode contains long bisvioletin side chains, which are less constrained by the main chain and are easy to stack during the electrode preparation process, which is beneficial to the transfer and diffusion of charge and ions during the charging and discharging process. The polyarylene ether compound of the main chain can effectively reduce the solubility of the bisvioletin side chains in the electrolyte and can also increase the flexibility of the organic polymer. Therefore, the organic polymer electrode of the present invention containing bisvioletin side chain functionalized polyarylene ether compound has the advantages of high viologen content, high theoretical specific capacity, high thermal stability and good flexibility. Sodium-ion batteries using high-stability organic polymer electrodes also have high charge and discharge capacity and excellent cycle stability.

[0025] Furthermore, the method for preparing the highly stable organic polymer electrode proposed in this invention has mild chemical reaction conditions, simple process, and is suitable for large-scale production.

[0026] Furthermore, the present invention also proposes a sodium-ion battery using the aforementioned highly stable organic polymer electrode as the positive electrode, which has high charge and discharge capacity and good cycle stability, and has the advantages of low cost and less environmental pollution after disposal, thus meeting the requirements of environmental protection and sustainable development. Attached Figure Description

[0027] Figure 1 The nuclear magnetic resonance (NMR) spectra of the relevant substances in the embodiments of the present invention are shown in the following figures: curve (a) is the NMR spectrum of the polyarylene ether compound TPAEK of Example 1; curve (b) is the NMR spectrum of the bromomethylated polyarylene ether compound Br-TPAEK of Example 2; and curve (c) is the NMR spectrum of the bisvioletin-functionalized polyarylene ether compound 2MV-TPAEK of Example 3.

[0028] Figure 2 The infrared spectra of the relevant substances in the embodiments of the present invention are shown in the following figures: curve (a) is the Fourier transform infrared spectrum of the polyarylene ether compound TPAEK prepared in Example 1; curve (b) is the Fourier transform infrared spectrum of the bromomethylated polyarylene ether compound Br-TPAEK prepared in Example 2; and curve (c) is the Fourier transform infrared spectrum of the bisvioletin-functionalized polyarylene ether compound 2MV-TPAEK prepared in Example 3.

[0029] Figure 3 The thermogravimetric curves of the relevant substances in the embodiments of the present invention are shown in the following figures: curve (a) is the thermogravimetric curve of the polyarylene ether compound TPAEK prepared in Example 1, curve (b) is the thermogravimetric curve of the bromomethylated polyarylene ether compound Br-TPAEK prepared in Example 2, and curve (c) is the thermogravimetric curve of the bisvioletin-functionalized polyarylene ether compound 2MV-TPAEK prepared in Example 3.

[0030] Figure 4 The charge-discharge curves of the coin cell sodium-ion battery prepared with a highly stable organic polymer electrode as the positive electrode in Example 5 of the present invention at a current rate of 0.1C for the first 10 cycles.

[0031] Figure 5 This is a cyclic voltammetry curve of a coin cell sodium-ion battery prepared using a highly stable organic polymer electrode as the positive electrode, according to Example 5 of the invention, at a scan rate of 5 mV s⁻¹. Detailed Implementation

[0032] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0033] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0035] A highly stable organic polymer electrode is composed of a bisvioletin side-chain functionalized polyarylene ether compound and nitrogen-doped carbon nanotubes.

[0036] The chemical structure of the bisvioletin side-chain functionalized polyaryl ether compound is as follows:

[0037] Where n is an integer between 20 and 300, and -R is -H or

[0038] The organic polymer electrode of the present invention contains long bisvioletin side chains, which are less constrained by the main chain and are easy to stack during electrode preparation. This facilitates the transfer and diffusion of charge and ions during charging and discharging. The polyarylene ether compound in the main chain can effectively reduce the solubility of the bisvioletin side chains in the electrolyte and also increase the flexibility of the organic polymer. Therefore, the organic polymer electrode of the present invention containing bisvioletin side chain functionalized polyarylene ether compounds has the advantages of high viologen content, high theoretical specific capacity, high thermal stability and good flexibility. Sodium-ion batteries using the highly stable organic polymer electrode also have high charge and discharge capacity and excellent cycle stability.

[0039] Furthermore, this invention proposes a method for preparing a highly stable organic polymer electrode, which includes the following steps:

[0040] S1) 3,3',5,5'-tetramethylbiphenyl, 4,4'-difluorobenzophenone and anhydrous potassium carbonate are added to N,N-dimethylacetamide and stirred to mix. Then toluene is added, and under inert gas protection, the temperature is raised to 140-150℃ and reacted for 1-5 hours. The water generated in the reaction is removed by reflux of toluene, and then the toluene is distilled off. The temperature is then raised to 150-170℃ and reacted for 12-24 hours. After cooling to room temperature, the mixture is poured into deionized water to precipitate the first precipitate. The first precipitate is collected by filtration and dried in a vacuum oven at 80-100℃ for 24 hours to obtain the polyarylene ether compound.

[0041] S2) The polyarylene ether compound and N-bromosuccinimide are mixed and dissolved in 1,2-dichloroethane. Benzoyl peroxide is used as an initiator. The reaction is carried out at 60-150°C for 6-60 hours under inert gas protection. After cooling to room temperature, the mixture is poured into methanol to precipitate a second precipitate. The second precipitate is collected by filtration and dried in a vacuum oven at 80-100°C for 24 hours to obtain the bromomethylated polyarylene ether compound.

[0042] S3) The bromomethylated polyarylene ether compound and 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound are mixed and dissolved in a polar aprotic solvent. Under inert gas protection and at 60-120°C, the mixture is reacted for 24-72 hours. The reaction solution is then poured into deionized water, and excess ammonium hexafluorophosphate is added to precipitate a third precipitate. The mixture is filtered, and the third precipitate is dried in a vacuum oven at 80-100°C for 24 hours. The dried third precipitate is then dissolved in a polar aprotic solvent, and iodomethane is added. Under inert gas protection and at 40-60°C, the mixture is reacted for 12-36 hours. The solution containing iodomethane is then poured into deionized water, and excess ammonium hexafluorophosphate is added to precipitate a first solid. The mixture is filtered, and the first solid is washed with methanol and deionized water. The washed first solid is then dried in a vacuum oven at 80-100°C for 24 hours to obtain the bisvioletin side-chain functionalized polyarylene ether compound.

[0043] S4) The bisvioletin side-chain functionalized polyaryl ether compound and nitrogen-doped carbon nanotubes are dispersed in N-methylpyrrolidone to form a slurry. After ultrasonic treatment for 1-3 hours, the slurry is uniformly coated onto aluminum foil and dried in a forced-air oven at 50-150°C for 1-5 hours, and then dried in a vacuum oven at 50-150°C for 12-36 hours to obtain the highly stable organic polymer electrode.

[0044] In step S1), the chemical structural formula of the polyarylether compound is shown below:

[0045] Where n is an integer between 20 and 200;

[0046] In step S2), the chemical structural formula of the bromomethylated polyarylether compound is shown below:

[0047] Where n is an integer between 20 and 300, and -R1 is -Br or -H;

[0048] In step S3), the chemical structural formula of the 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound is shown below:

[0049]

[0050] The method for preparing the highly stable organic polymer electrode of the invention firstly prepares a benzyl polyarylene ether compound based on 3,3',5,5'-tetramethylbiphenyl, then brominates the benzyl group with N-bromosuccinimide to obtain a bromomethylated polyarylene ether compound, then reacts the bromomethylated polyarylene ether compound with a 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound, and then reacts it with iodomethane to obtain a bisvioletin side-chain functionalized polyarylene ether compound, and then mixes the obtained bisvioletin side-chain functionalized polyarylene ether compound with nitrogen-doped carbon nanotubes to obtain a highly stable organic polymer electrode.

[0051] The preparation method provided by this invention features mild chemical reaction conditions, a simple process, and is suitable for large-scale production. The resulting electrode can be used as the positive electrode in sodium-ion batteries. This electrode exhibits good cycle stability and has the advantages of low cost and minimal environmental pollution after disposal, thus meeting the requirements of environmental protection and sustainable development.

[0052] Preferably, in step S1), the molar ratio of 3,3',5,5'-tetramethylbiphenyl, 4,4'-difluorobenzophenone and anhydrous potassium carbonate is 1:1:(3-6).

[0053] Preferably, in step S1), the volume ratio of N,N-dimethylacetamide to toluene is 1:(0.1-1); the volume of N,N-dimethylacetamide corresponding to each mole of 3,3',5,5'-tetramethylbiphenyl is 1-6 mL.

[0054] Preferably, in step S2), the molar ratio of the polyarylene ether compound, N-bromosuccinimide, and benzoyl peroxide is 1:(2-8):(0.1-0.02); and the volume of 1,2-dichloroethane corresponding to each gram of polyarylene ether compound is 10-100 mL.

[0055] Preferably, in step S3), the molar ratio of the bromomethylated polyarylene ether compound, the 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound to iodomethane is 1:(2-12):(4-20); and the volume of polar aprotic solvent corresponding to each gram of bromomethylated polyarylene ether compound is 10-100 mL.

[0056] Preferably, in step S3), the polar aprotic solvent is any one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0057] Preferably, in step S4), the mass ratio of the bisvioletin side-chain functionalized polyarylene ether compound to the nitrogen-doped carbon nanotube is 1:(0.1-1); the amount of N-methylpyrrolidone corresponding to each gram of bisvioletin side-chain functionalized polyarylene ether compound is 3-20 mL.

[0058] Furthermore, the present invention also proposes a sodium-ion battery, wherein the positive electrode is prepared using the above-described method for preparing a highly stable organic polymer electrode.

[0059] Using the highly stable organic polymer electrode of the present invention as the positive electrode of a sodium-ion battery not only has high charge-discharge capacity and good cycle stability, but also has the advantages of low cost, no toxic precious metals, and less environmental pollution after disposal, which can meet the requirements of environmental protection and sustainable development.

[0060] Example

[0061] Example 1: Preparation of the polyarylene ether compound TPAEK

[0062] In a 200 mL three-necked round-bottom flask equipped with an argon gas passage, reflux device, water separator, and magnetic stirrer, add 2.4232 g (10.0 mmol) of 3,3',5,5'-tetramethylbiphenylhydrazine, 2.1820 g (10.0 mmol) of 4,4'-difluorobenzophenone, 4.14 g (30.0 mmol) of anhydrous potassium carbonate, 50 mL of N,N-dimethylacetamide (DMAC), and 15 mL of toluene. Under argon protection, heat to 1 °C. The mixture was heated to 40°C for 3 hours to allow the water produced to be removed by reflux of toluene. Toluene was then distilled off, the temperature was increased to 160°C, and the reaction was continued for 12 hours. After cooling to room temperature, the resulting viscous mixture was poured into 500 mL of deionized water to precipitate the product. The precipitate was collected by filtration and dried in a vacuum drying oven at 80°C for 24 hours to obtain the polyarylether compound TPAEK with a yield of 96%. The 1H NMR spectrum of TPAEK is shown below. Figure 1 The curve (a) in the figure, and the infrared spectrum are shown in [reference needed]. Figure 2 The curve (a) and the thermogravimetric curve are shown in Figure 1. Figure 3 Curve (a) in the figure.

[0063] Example 2: Preparation of the bromomethylated polyarylene ether compound Br-TPAEK

[0064] In a 150 mL three-necked round-bottom flask, 1.05 g (2.50 mmol) of the polyarylene ether compound TPAEK prepared in Example 1, 2.37 g (13.33 mmol) of N-bromosuccinimide (NBS), 0.16 g (0.67 mmol) of benzoyl peroxide (BPO), and 60 mL of 1,2-dichloroethane were added. The mixture was then reacted at 80 °C for 24 hours under argon protection. After the reaction was complete, the product was poured into methanol to precipitate, and the precipitate was collected by filtration. The precipitate was then dried in a vacuum oven at 80 °C for 24 hours to obtain the bromomethylated polyarylene ether Br-TPAEK, with a yield of 93%. The 1H NMR spectrum of the bromomethylated polyarylene ether Br-TPAEK product is shown below. Figure 1 Curve (b) shows that the degree of bromomethylation of the bromomethylated polyarylene ether Br-TPAEK product is 99.5% through integration. The infrared spectrum of the bromomethylated polyarylene ether Br-TPAEK product is shown in [reference needed]. Figure 2 Curve (b) and thermogravimetric curve are shown in [the original text]. Figure 3 Curve (b) in the figure.

[0065] Example 3: Preparation of 2MV-TPAEK, a polyaryl ether compound with bisvioletin side chain functionalization

[0066] In a 50 mL three-necked round-bottom flask equipped with a magnetic stirrer, thermometer, reflux device, and argon gas passage, 0.36 g (0.5 mmol) of the bromomethylated polyarylene ether Br-TPAEK prepared in Example 2, 2.82 g (4 mmol) of 1,1'-(1,4-phenylene)bis-4',4”-bipyridine compound, and 25 mL of N-methylpyrrolidone were added. The mixture was reacted at 80 °C for 2 days. After the reaction was completed, the mixture was poured into 500 mL of deionized water, and 20 g of ammonium hexafluorophosphate was added to precipitate the precipitate. The precipitate was filtered, dried, and then dried in a vacuum oven at 80 °C for 24 hours. The precipitate was then dissolved in 25 mL of N-methylpyrrolidone. In a ketone mixture, 0.85 g (6 mmol) of iodomethane was added, and the mixture was reacted at 60 °C for 1 day under argon protection. The reactants were then poured into 500 mL of deionized water, and 20 g of ammonium hexafluorophosphate was added to precipitate the mixture. After filtration, the precipitate was washed with 200 mL of methanol and 200 mL of deionized water. The precipitate was then dried in a vacuum oven at 80 °C for 24 hours to obtain the bisvioletin side-chain functionalized polyaryl ether compound 2MV-TPAEK, with a yield of 90%. The 1H NMR spectrum of the bisvioletin side-chain functionalized polyaryl ether compound 2MV-TPAEK is shown below. Figure 1 Curve (c) in the middle, from Figure 1 As can be seen from curve (c), all bromomethyl groups participated in the reaction; the infrared spectrum of this bisvioletin side-chain functionalized polyarylene ether compound 2MV-TPAEK is shown in [reference needed]. Figure 2 Curve (c) and thermogravimetric curve are shown in [the original text]. Figure 3 Curve (c) is shown in the figure. Testing revealed that the bisvioletin side-chain functionalized polyarylether compound 2MV-TPAEK is almost insoluble in organic electrolytes containing carbonates and ethers, but readily soluble in polar aprotic solvents such as N-methylpyrrolidone, dimethyl sulfoxide, or N,N-dimethylacetamide. A solution of bisvioletin side-chain functionalized polyarylether compound 2MV-TPAEK in a polar aprotic solvent was dissolved, cast into a film, and dried in a vacuum oven at 80°C for 24 hours to obtain a dumbbell-shaped sample. Tensile testing revealed a tensile strength of 25 MPa and an elongation at break of 16%.

[0067] Example 4: Preparation of a highly stable organic polymer electrode

[0068] Take 0.6g of the bisvioletin side-chain functionalized polyarylene ether compound 2MV-TPAEK prepared in Example 3 and 0.4g of nitrogen-doped carbon nanotubes, grind them into a slurry in 5mL of N-methylpyrrolidone, sonicate for 1 hour, then coat it uniformly on aluminum foil, dry it in a forced-air oven at 80°C for 1 hour, and then dry it in a vacuum oven at 120°C for 24 hours to obtain the highly stable organic polymer electrode.

[0069] Example 5: Fabrication of a coin cell sodium-ion battery using the highly stable organic polymer electrode from Example 4

[0070] The highly stable organic polymer electrode prepared in Example 4 was cut into 14 mm diameter discs and used as the positive electrode. Sodium metal was used as the negative electrode, Celgard 2400 was used as the separator, and 1 mol / L sodium hexafluorophosphate was used as the electrolyte (the electrolyte salt was sodium hexafluorophosphate, and the solvent was 1,2-ethylene glycol carbonate and dimethyl carbonate in a volume ratio of 1:1). The CR2025 coin cell was assembled in an argon-filled glove box. The coin cell was then tested using a Newwell battery charge-discharge tester and a Chenhua electrochemical workstation. The charge-discharge curve of the sodium-ion coin cell at a current rate of 0.1C for the first 10 cycles is shown in the figure. Figure 4 As shown, the cyclic voltammetry curve of this coin cell sodium-ion battery at a scan rate of 5 mV s⁻¹ is as follows. Figure 5 As shown.

[0071] Figure 4 and Figure 5 The results show that the electrochemical data of the coin cell sodium-ion battery prepared with the highly stable organic polymer electrode as the positive electrode are shown in the table below.

[0072] Table 1. Electrochemical data of the coin cell sodium-ion battery in Example 5.

[0073]

[0074] In summary, the highly stable organic polymer electrode contains relatively long bisvioletin side chains, which are less constrained by the main chain. These side chains are easily stacked during electrode preparation, facilitating charge and ion transfer and diffusion during charging and discharging. The polyarylene ether compound in the main chain effectively reduces the solubility of the bisvioletin side chains in the electrolyte and also increases the flexibility of the organic polymer. Therefore, the organic polymer electrode of the present invention, containing bisvioletin side chain functionalized polyarylene ether compounds, has the advantages of high viologen content, high theoretical specific capacity, high thermal stability, and good flexibility. Sodium-ion batteries using this highly stable organic polymer electrode also exhibit high charge-discharge capacity and excellent cycle stability.

[0075] Furthermore, the method for preparing the highly stable organic polymer electrode proposed in this invention has mild chemical reaction conditions, simple process, and is suitable for large-scale production.

[0076] Furthermore, the present invention also proposes a sodium-ion battery using the aforementioned highly stable organic polymer electrode as the positive electrode, which has high charge and discharge capacity and good cycle stability, and has the advantages of low cost and less environmental pollution after disposal, thus meeting the requirements of environmental protection and sustainable development.

[0077] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A highly stable organic polymer electrode, characterized by, Consist of diathienylpyridine side chain functionalized polyarylether compound and nitrogen-doped carbon nanotube; The chemical structure of the diathienylpyridine side chain functionalized polyarylether compound is: wherein n = an integer from 20 to 300, -R is -H or 2. A method for preparing a highly stable organic polymer electrode, characterized in that, The application relates to a high-stability organic polymer electrode and a preparation method thereof. S1) 3,3',5,5'-tetramethylbenzophenone, 4,4'-difluorobenzophenone and anhydrous potassium carbonate are added into N,N-dimethylacetamide, the mixture is stirred and mixed, then toluene is added, under the protection of inert gas, the temperature is raised to 140-150 DEG C, reaction is carried out for 1-5 hours, the water generated in the reaction is taken out by toluene reflux, then toluene is evaporated, the temperature is raised to 150-170 DEG C again, reaction is carried out for 12-24 hours, after being cooled to room temperature, the first precipitate is separated out by pouring into deionized water, the first precipitate is collected by filtration, and the first precipitate is dried in a vacuum oven at 80-100 DEG C for 24 hours, so that the polyarylether compound is prepared; S2) the polyarylether compound and N-bromosuccinimide are mixed and dissolved in 1,2-dichloroethane, benzoyl peroxide is used as an initiator, under the protection of inert gas, reaction is carried out at 60-150 DEG C for 6-60 hours, after being cooled to room temperature, the second precipitate is separated out by pouring into methanol, the second precipitate is collected by filtration, and the second precipitate is dried in a vacuum oven at 80-100 DEG C for 24 hours, so that the bromomethylated polyarylether compound is prepared; S3) the bromomethylated polyarylether compound and 1,1'-(1,4-phenylene) bis-4',4"-bipyridine compound are mixed and dissolved in a polar aprotic solvent, reaction is carried out under the protection of inert gas and at 60-120 DEG C for 24-72 hours, then the reaction solution is poured into deionized water, excessive ammonium hexafluorophosphate is added to separate out the third precipitate, the third precipitate is filtered, and the third precipitate is dried in a vacuum oven at 80-100 DEG C for 24 hours, then the dried third precipitate is dissolved in a polar aprotic solvent, iodomethane is added, reaction is carried out under the protection of inert gas and at 40-60 DEG C for 12-36 hours, then the solution containing iodomethane is poured into deionized water, excessive ammonium hexafluorophosphate is added to separate out the first solid, the first solid is filtered, and the first solid is cleaned with methanol and deionized water, then the cleaned first solid is dried in a vacuum oven at 80-100 DEG C for 24 hours, so that the diathienylpyridine side chain functionalized polyarylether compound is prepared; S4) the diathienylpyridine side chain functionalized polyarylether compound and nitrogen-doped carbon nanotube are dispersed in N-methylpyrrolidone to form a slurry, ultrasonic treatment is carried out for 1-3 hours, then the slurry is uniformly coated on an aluminum foil, drying is carried out in a blast oven at 50-150 DEG C for 1-5 hours, and then drying is carried out in a vacuum oven at 50-150 DEG C for 12-36 hours, so that the high-stability organic polymer electrode is prepared.

3. The method of claim 2, wherein the method is characterized by, In step S1), the molar ratio of 3,3',5,5'-tetramethylbenzophenone, 4,4'-difluorobenzophenone and anhydrous potassium carbonate is 1:1:(3-6).

4. The method of claim 2, wherein the organic polymer electrode is prepared by the steps of: (a) dissolving the organic polymer and the electrolyte in a solvent to prepare a solution; (b) coating the solution on a substrate to form a film; and (c) drying the film. In step S1), the volume ratio of N,N-dimethylacetamide to toluene is 1:(0.1-1); the volume of N,N-dimethylacetamide corresponding to each mole of 3,3',5,5'-tetramethylbiphenyl diol is 1-6 mL.

5. The method of claim 2, wherein the organic polymer electrode is prepared by the steps of: (a) dissolving the organic polymer and the electrolyte in a solvent to prepare a solution; (b) coating the solution on a substrate to form a film; and (c) drying the film. In step S2), the molar ratio of the polyarylether compound, N-bromosuccinimide and benzoyl peroxide is 1:(2-8):(0.1-0.02); the volume of 1,2-dichloroethane corresponding to each gram of the polyarylether compound is 10-100 mL.

6. The method of claim 2, wherein the organic polymer electrode is prepared by the steps of: (a) dissolving the organic polymer and the electrolyte in a solvent to prepare a solution; (b) coating the solution on a substrate to form a film; and (c) drying the film. In step S3), the molar ratio of the bromomethylated polyarylether compound, 1,1'-(1,4-phenylene)bis-4',4"-bipyridine compound and iodomethane is 1:(2-12):(4-20); the volume of the polar aprotic solvent corresponding to each gram of the bromomethylated polyarylether compound is 10-100 mL.

7. The method of claim 2, wherein the organic polymer electrode is prepared by the steps of: (a) dissolving the organic polymer and the electrolyte in a solvent to prepare a solution; (b) coating the solution on a substrate to form a film; and (c) drying the film. In step S3), the polar aprotic solvent is any one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

8. The method of claim 2, wherein the organic polymer electrode is prepared by the steps of: (a) dissolving the organic polymer and the electrolyte in a solvent to prepare a solution; (b) coating the solution on a substrate to form a film; and (c) drying the film. In step S4), the mass ratio of the diathiafulvene side chain functionalized polyarylether compound and nitrogen-doped carbon nanotube is 1:(0.1-1); the amount of N-methylpyrrolidone corresponding to each gram of the diathiafulvene side chain functionalized polyarylether compound is 3-20 mL.

9. A sodium-ion battery, characterized in that, The positive electrode prepared by the preparation method of the high-stability organic polymer electrode according to any one of claims 2-8. In step S1), the volume ratio of N,N-dimethylacetamide to toluene is 1:(0.1-1); the volume of N,N-dimethylacetamide corresponding to each mole of 3,3',5,5'-tetramethylbiphenyl diol is 1-6 mL. In step S2), the molar ratio of the polyarylether compound, N-bromosuccinimide and benzoyl peroxide is 1:(2-8):(0.1-0.02); the volume of 1,2-dichloroethane corresponding to each gram of the polyarylether compound is 10-100 mL. In step S3), the molar ratio of the bromomethylated polyarylether compound, 1,1'-(1,4-phenylene)bis-4',4"-bipyridine compound and iodomethane is 1:(2-12):(4-20); the volume of the polar aprotic solvent corresponding to each gram of the bromomethylated polyarylether compound is 10-100 mL. In step S3), the polar aprotic solvent is any one of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide. In step S4), the mass ratio of the diathiafulvene side chain functionalized polyarylether compound and nitrogen-doped carbon nanotube is 1:(0.1-1); the amount of N-methylpyrrolidone corresponding to each gram of the diathiafulvene side chain functionalized polyarylether compound is 3-20 mL. The positive electrode prepared by the preparation method of the high-stability organic polymer electrode according to any one of claims 2-8.

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