Phenazine polymer positive electrode material for sodium ion start-stop battery and preparation method of phenazine polymer positive electrode material
By using a method of mixing modified phenazine polymers with conductive agents and binders, the electronic conductivity and cycle stability of the positive electrode material for sodium-ion start-stop batteries were improved, overcoming the shortcomings of existing materials and achieving excellent performance in sodium-ion start-stop batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU TRANSIMAGE TECH CO LTD
- Filing Date
- 2026-01-26
- Publication Date
- 2026-05-01
AI Technical Summary
Existing phenazine polymer cathode materials suffer from insufficient electronic conductivity, easy solubility, and poor cycle stability in sodium-ion start-stop batteries, which limits their application in sodium-ion start-stop batteries.
A modified phenazine polymer cathode material was prepared by mixing modified phenazine polymers with conductive agents and binders to form a slurry, which was then coated onto the surface of an aluminum foil current collector. The modified phenazine polymers introduced pyrene rings and carbazole groups through a multi-step chemical reaction, thereby improving electronic conductivity and structural stability.
Modified phenazine polymer cathode materials exhibit excellent electronic conductivity and cycle stability, making them suitable for sodium-ion start-stop batteries. They also possess good electrochemical performance and cycle stability, making them suitable for large-scale production.
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Abstract
Description
Phenazine polymer cathode materials for sodium-ion start-stop batteries and their preparation methods Technical Field
[0001] This invention relates to the field of cathode materials, specifically to phenazine polymer cathode materials for sodium-ion start-stop batteries and their preparation methods. Background Technology
[0002] With the rapid development of the new energy industry, the demand for energy storage and power batteries is increasing. Sodium-ion batteries, due to the high abundance and low cost of sodium resources in the earth's crust, have become an important supplement to lithium-ion batteries and have broad application prospects in large-scale energy storage, low-speed electric vehicles, and other fields. Among them, sodium-ion start-stop batteries, as a battery for a special application scenario, require electrode materials with excellent fast charge and discharge capabilities, good cycle stability, and high energy density to meet the performance requirements during frequent start-stop processes.
[0003] Cathode materials are one of the core components determining the performance of sodium-ion batteries. Currently, sodium-ion battery cathode materials mainly include layered oxides, polyanionic compounds, and organic polymer materials. Although layered oxide materials have a theoretically high specific capacity, they suffer from problems such as irreversible phase transitions, poor air stability, and transition metal dissolution, leading to limited cycle life. Polyanionic compounds, on the other hand, have drawbacks such as poor electronic conductivity and poor rate performance. Organic polymer cathode materials have advantages such as abundant resources, strong structural designability, and environmental friendliness. Among them, phenazine polymers, due to their excellent hole transport performance and conjugated π-electron system, can stabilize the molecular and ionic states of active materials, making them one of the most promising cathode materials for sodium-ion batteries.
[0004] However, when pure phenazine polymers are used as positive electrode materials, they still have problems such as insufficient electronic conductivity, easy solubility in electrolyte, and rapid capacity decay during cycling. In actual use, they exhibit poor electrochemical performance and cycle stability, which limits their application in sodium-ion start-stop batteries. Summary of the Invention
[0005] To overcome the aforementioned technical problems, the present invention aims to provide a phenazine polymer cathode material for sodium-ion start-stop batteries and its preparation method, thereby solving the problem that the poor electrochemical performance and cycle stability of existing phenazine polymer cathode materials limit their application in sodium-ion start-stop batteries.
[0006] The objective of this invention can be achieved through the following technical solution: Firstly, this application provides a phenazine polymer positive electrode material for sodium-ion start-stop batteries, which is formed by grinding a modified phenazine polymer, a conductive agent, and a binder into a slurry, and then coating the slurry onto the surface of an aluminum foil current collector and drying it; wherein, the modified phenazine polymer is prepared by the following steps: Step a1: Sodium dithionite, anhydrous ethanol, and deionized water are added to a three-necked flask equipped with a stirrer, a thermometer, and a gas delivery tube, nitrogen gas is introduced for protection, and the mixture is stirred and reacted for 20-30 minutes at a temperature of 20-25°C and a stirring rate of 200-300 r / min, after which... Add phenazine and continue stirring for 20-30 min. Then, raise the temperature to 80-90℃ and continue stirring for 3-5 h. After the reaction is complete, cool the reaction product to room temperature, then filter under vacuum. Wash the filter cake 2-3 times with distilled water, then place it in a vacuum drying oven and dry it at 80-90℃ for 5-6 h to obtain dihydrophenazine. Step a2: Add 1-pyrene methanol, potassium hydroxide, and tetrahydrofuran to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant pressure dropping funnel. Purge with nitrogen for protection and stir the reaction at 20-25℃ and a stirring rate of 200-300 r / min for 1-1.After 5 hours, 1,4-dibromobutane was added dropwise while stirring, with a dropping rate of 1-3 drops / s. After the addition was complete, the temperature was raised to 50-55℃ and the reaction was stirred for another 4-5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then poured into ice water. It was then extracted 2-3 times with ethyl acetate. The extracts were combined and washed 2-3 times successively with distilled water and saturated saline solution. The mixture was then dried with anhydrous sodium sulfate and vacuum filtered. The filtrate was evaporated by rotary evaporation to remove the solvent. The mixture was then subjected to silica gel column chromatography with petroleum ether as the eluent and recrystallized with anhydrous ethanol to obtain the bromoalkylpyrene ring compound. Step a3: The bromoalkylpyrene ring compound, 2,7-dibromocarbazole, potassium hydroxide, and dimethyl sulfoxide were added to a container equipped with a stirrer and a thermometer. In a three-necked flask with a gas delivery tube, nitrogen gas was introduced for protection. The reaction was stirred for 6-8 hours at a temperature of 20-25℃ and a stirring rate of 200-300 r / min. After the reaction was completed, the reaction product was poured into ice water and then extracted 2-3 times with dichloromethane. The extracts were combined and washed 2-3 times with distilled water and saturated saline solution, respectively. The mixture was then dried with anhydrous sodium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then subjected to silica gel column chromatography with petroleum ether as the eluent and recrystallized with n-hexane to obtain the pyrenecyclodibromocarbazole compound. Step a4: Dihydrophenazine, pyrenecyclodibromocarbazole compound, sodium tert-butoxide, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, RuPhos PdG2 catalyst and xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The reaction mixture was stirred at 20-25°C and a stirring rate of 200-300 rpm for 20-30 minutes. The temperature was then raised to 110-120°C, and the reaction was continued with stirring for 24-48 hours. After the reaction was complete, the product was cooled to room temperature and centrifuged. The precipitate was washed 2-3 times successively with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran. The precipitate was then placed in a vacuum drying oven and dried at 80-90°C for 5-6 hours to obtain the modified phenazine polymer.
[0007] In a preferred embodiment of the present invention, the ratio of sodium dithionite, anhydrous ethanol, deionized water and phenazine in step a1 is 100-110 mmol: 50-60 mL: 130-150 mL: 10 mmol.
[0008] In a preferred embodiment of the present invention, the ratio of 1-pyrene methanol, potassium hydroxide, tetrahydrofuran and 1,4-dibromobutane in step a2 is 20 mmol: 25-30 mmol: 50-60 mL: 20 mmol.
[0009] In a preferred embodiment of the present invention, the ratio of the bromoalkylpyrene ring compound, 2,7-dibromocarbazole, potassium hydroxide and dimethyl sulfoxide in step a3 is 13-15 mmol: 10 mmol: 30-40 mmol: 80-90 mL.
[0010] In a preferred embodiment of the present invention, the ratio of dihydrophenazine, pyrene cyclodibromocarbazole compound, sodium tert-butoxide, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, RuPhos Pd G2 catalyst, and xylene in step a4 is 10 mmol: 10 mmol: 0.4-0.5 g: 15-20 mg: 20-30 mg: 60-80 mL.
[0011] Secondly, this application provides a method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, comprising the following steps: mixing a modified phenazine polymer, a conductive agent, and a binder uniformly, then adding N-methylpyrrolidone to adjust the solid content to 40%, followed by grinding to form a slurry, coating the slurry onto the surface of an aluminum foil current collector, and then placing it in a vacuum drying oven and drying it at 60°C for 12 hours to obtain a loading of 1.30±0.05 mg / cm³. 2 Phenozine polymer cathode material for sodium-ion start-stop batteries.
[0012] In a preferred embodiment of the present invention, the mass ratio of the modified phenazine polymer, the conductive agent, and the binder is 6:3:1.
[0013] In a preferred embodiment of the present invention, the conductive agent is Ketjenblack EC300J.
[0014] In a preferred embodiment of the present invention, the adhesive is Solvay PVDF 6020.
[0015] The beneficial effects of this invention are as follows: The phenazine polymer positive electrode material for sodium-ion start-stop batteries and its preparation method are as follows: A modified phenazine polymer, a conductive agent, and a binder are mixed evenly, then N-methylpyrrolidone is added and ground to form a slurry. The slurry is then coated onto the surface of an aluminum foil current collector and dried to obtain the phenazine polymer positive electrode material for sodium-ion start-stop batteries. This positive electrode material uses a modified phenazine polymer as the active material. Due to the presence of multiple functional groups in its structure, it can provide higher electronic conductivity and better stability, enabling it to exhibit excellent performance in start-stop batteries. Moreover, the preparation method is simple, easy to scale up, and has good prospects for industrial application.
[0016] In the preparation of phenazine polymer cathode materials, a modified phenazine polymer was first prepared. Firstly, phenazine was reduced using sodium dithionite to convert nitrogen atoms to NH bonds, yielding dihydrophenazine. Then, a reaction was carried out using 1-pyrene methanol and 1,4-dibromobutane, where the hydroxyl group on 1-pyrene methanol reacted with the bromine atom on 1,4-dibromobutane, simultaneously introducing a bromine atom to obtain a bromoalkylpyrene ring compound. Next, a reaction was carried out using the bromoalkylpyrene ring compound and 2,7-dibromocarbazole, where the bromine atom on the bromoalkylpyrene ring reacted with the NH bond on 2,7-dibromocarbazole, simultaneously introducing a pyrene ring to obtain a pyrene-cyclic dibromocarbazole compound. Finally, a reaction was carried out using dihydrophenazine and pyrene... Cyclodibromocarbazole compounds undergo polymerization to obtain modified phenazine polymers. The molecular structure of these modified phenazine polymers is based on phenazine and carbazole units. Phenazines possess high theoretical capacity due to their multi-electron reversible redox activity. Introducing carbazole groups can enhance the stability and hole transport performance of phenazine compounds. The pyrene ring has a large conjugated system and strong π-π interactions. Introducing it into the polymer side chain can improve intermolecular forces, enhance the structural stability and conductivity of the material, and thus endow the modified phenazine polymers with excellent conductivity and stability. As a result, the cathode materials based on these polymers exhibit good electrochemical performance and cycle stability. Detailed Implementation
[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0018] Example 1:
[0019] This embodiment describes a method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, comprising the following steps: Step S1: 100 mmol of sodium dithionite, 50 mL of anhydrous ethanol, and 130 mL of deionized water are added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas is introduced for protection, and the mixture is stirred for 20 min at 20°C and a stirring rate of 200 r / min. Then, 10 mmol of phenazine is added, and the mixture is stirred for another 20 min. The mixture is then heated to 80°C and stirred for another 3 h. After the reaction is complete, the reaction product is cooled to room temperature and then vacuum filtered. The filter cake was washed twice with distilled water and then placed in a vacuum drying oven and dried at 80°C for 5 hours to obtain dihydrophenazine. Step S2: 20 mmol of 1-pyrene methanol, 25 mmol of potassium hydroxide, and 50 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant-pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 20°C and a stirring rate of 200 r / min for 1 hour. Then, 20 mmol of 1,4-dibromobutane was added dropwise while stirring, controlling the dropping rate at 1 drop / s. After the addition was complete, the temperature was raised to 50°C, and the reaction was continued with stirring. After 4 hours of reaction, the reaction product was cooled to room temperature and then poured into ice water. It was then extracted twice with ethyl acetate. The extracts were combined and washed twice successively with distilled water and saturated saline solution. The mixture was dried over anhydrous sodium sulfate and then filtered under vacuum. The filtrate was evaporated by rotary evaporation to remove the solvent. The solution was then subjected to silica gel column chromatography using petroleum ether as eluent, followed by recrystallization with anhydrous ethanol to obtain the bromoalkylpyrene ring compound. Step S3: 13 mmol of the bromoalkylpyrene ring compound, 10 mmol of 2,7-dibromocarbazole, 30 mmol of potassium hydroxide, and 80 mL of dimethyl sulfoxide were added to a container equipped with a stirrer, thermometer, and... In a three-necked flask with a gas purging system, nitrogen was introduced for protection. The reaction was stirred at 20°C and 200 r / min for 6 h. After the reaction was completed, the product was poured into ice water and then extracted twice with dichloromethane. The extracts were combined and washed twice, successively with distilled water and saturated saline solution. The mixture was then dried with anhydrous sodium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then subjected to silica gel column chromatography with petroleum ether as the eluent and recrystallized with n-hexane to obtain the pyrenecyclodibromocarbazole compound. Step S4: 10 mmol of dihydrophenazine, 10 mmol of the pyrenecyclodibromocarbazole compound, and 0.4g sodium tert-butoxide, 15mg 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, 20mg RuPhos Pd G2 catalyst, and 60mL xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred at 20℃ and 200r / min for 20min, then heated to 110℃ and stirred for 24h. After the reaction, the product was cooled to room temperature and centrifuged. The precipitate was washed twice with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran, respectively. It was then placed in a vacuum drying oven and dried at 80℃ for 5h to obtain the modified phenazine polymer. Step S5: The modified phenazine polymer, conductive agent Ketjenblack EC300J, and binder Solvay PVDF were added. 6020 was mixed evenly at a mass ratio of 6:3:1, and then N-methylpyrrolidone was added to adjust the solid content to 40%. The mixture was then ground to form a slurry, which was coated onto the surface of an aluminum foil current collector. The slurry was then placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain a phenazine polymer cathode material for sodium-ion start-stop batteries.
[0020] Example 2:
[0021] This embodiment describes a method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, comprising the following steps: Step S1: 105 mmol of sodium dithionite, 55 mL of anhydrous ethanol, and 140 mL of deionized water are added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas is introduced for protection, and the mixture is stirred for 25 min at 22°C and a stirring rate of 250 r / min. Then, 10 mmol of phenazine is added, and the mixture is stirred for another 25 min. The mixture is then heated to 85°C and stirred for another 4 h. After the reaction is complete, the reaction product is cooled to room temperature and then vacuum filtered. The filtered product is then... The cake was washed twice with distilled water and then placed in a vacuum drying oven and dried at 85°C for 5.5 h to obtain dihydrophenazine. Step S2: 20 mmol of 1-pyrene methanol, 28 mmol of potassium hydroxide, and 55 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant-pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 22°C and a stirring rate of 250 r / min for 1.2 h. Then, 20 mmol of 1,4-dibromobutane was added dropwise while stirring, controlling the dropping rate at 2 drops / s. After the addition was complete, the temperature was raised to 52°C and stirring continued. After 4.5 hours of reaction, the reaction product was cooled to room temperature and then poured into ice water. It was then extracted twice with ethyl acetate. The extracts were combined and washed twice successively with distilled water and saturated saline solution. The mixture was dried over anhydrous sodium sulfate and then vacuum filtered. The filtrate was evaporated by rotary evaporation to remove the solvent. The solution was then subjected to silica gel column chromatography using petroleum ether as eluent, followed by recrystallization with anhydrous ethanol to obtain the bromoalkylpyrene ring compound. Step S3: 14 mmol of the bromoalkylpyrene ring compound, 10 mmol of 2,7-dibromocarbazole, 35 mmol of potassium hydroxide, and 85 mL of dimethyl sulfoxide were added to a container equipped with a stirrer, thermometer, and... Nitrogen gas was introduced into a three-necked flask with a gas delivery tube for protection. The reaction was stirred for 7 hours at 22°C and a stirring rate of 250 r / min. After the reaction was completed, the reaction product was poured into ice water and then extracted twice with dichloromethane. The extracts were combined and washed twice with distilled water and saturated saline solution, respectively. The mixture was then dried with anhydrous sodium sulfate and vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then subjected to silica gel column chromatography with petroleum ether as the eluent and recrystallized with n-hexane to obtain the pyrenecyclodibromocarbazole compound. Step S4: 10 mmol of dihydrophenazine, 10 mmol of the pyrenecyclodibromocarbazole compound, and 0.45g sodium tert-butoxide, 18mg 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, 25mg RuPhos Pd G2 catalyst, and 70mL xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred at 22℃ and 250r / min for 25min, then heated to 115℃ and stirred for 36h. After the reaction, the product was cooled to room temperature and centrifuged. The precipitate was washed twice with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran, respectively. It was then dried in a vacuum drying oven at 85℃ for 5.5h to obtain the modified phenazine polymer. Step S5: The modified phenazine polymer, conductive agent Ketjenblack EC300J, and binder Solvay PVDF were added. 6020 was mixed evenly at a mass ratio of 6:3:1, and then N-methylpyrrolidone was added to adjust the solid content to 40%. The mixture was then ground to form a slurry, which was coated onto the surface of an aluminum foil current collector. The slurry was then placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain a phenazine polymer cathode material for sodium-ion start-stop batteries.
[0022] Example 3:
[0023] This embodiment describes a method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, comprising the following steps: Step S1: 110 mmol of sodium dithionite, 60 mL of anhydrous ethanol, and 150 mL of deionized water are added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas is introduced for protection, and the mixture is stirred at 25°C and a stirring rate of 300 r / min for 30 min. Then, 10 mmol of phenazine is added, and the mixture is stirred for another 30 min. The temperature is then raised to 90°C, and the mixture is stirred for another 5 h. After the reaction is complete, the reaction product is cooled to room temperature and then vacuum filtered. The filter cake was washed three times with distilled water and then placed in a vacuum drying oven and dried at 90°C for 6 hours to obtain dihydrophenazine. Step S2: 20 mmol of 1-pyrene methanol, 30 mmol of potassium hydroxide, and 60 mL of tetrahydrofuran were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and constant-pressure dropping funnel. Nitrogen gas was introduced for protection, and the reaction was stirred at 25°C and a stirring rate of 300 r / min for 1.5 hours. Then, 20 mmol of 1,4-dibromobutane was added dropwise while stirring, controlling the dropping rate at 3 drops / s. After the addition was complete, the temperature was raised to 55°C and stirring continued. After 5 hours of reaction, the reaction product was cooled to room temperature and then poured into ice water. It was then extracted three times with ethyl acetate. The extracts were combined and washed three times successively with distilled water and saturated saline solution. The mixture was dried over anhydrous sodium sulfate and then vacuum filtered. The filtrate was evaporated by rotary evaporation to remove the solvent. The solution was then subjected to silica gel column chromatography using petroleum ether as eluent and recrystallized with anhydrous ethanol to obtain the bromoalkylpyrene ring compound. Step S3: 15 mmol of the bromoalkylpyrene ring compound, 10 mmol of 2,7-dibromocarbazole, 40 mmol of potassium hydroxide, and 90 mL of dimethyl sulfoxide were added to a container equipped with a stirrer, thermometer, and... In a three-necked flask with a tracheal tube, nitrogen gas was introduced for protection. The reaction was stirred at 25°C and a stirring rate of 300 r / min for 8 h. After the reaction was completed, the reaction product was poured into ice water and then extracted three times with dichloromethane. The extracts were combined and washed three times successively with distilled water and saturated saline solution. The mixture was then dried with anhydrous sodium sulfate and vacuum filtered. The filtrate was evaporated by rotary evaporation to remove the solvent. The mixture was then subjected to silica gel column chromatography with petroleum ether as the eluent and recrystallized with n-hexane to obtain the pyrenecyclodibromocarbazole compound. Step S4: 10 mmol of dihydrophenazine, 10 mmol of the pyrenecyclodibromocarbazole compound, and 0.5g sodium tert-butoxide, 20mg 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, 30mg RuPhos Pd G2 catalyst, and 80mL xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred at 25℃ and 300r / min for 30min, then heated to 120℃ and stirred for 48h. After the reaction, the product was cooled to room temperature and centrifuged. The precipitate was washed three times successively with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran. It was then placed in a vacuum drying oven and dried at 90℃ for 6h to obtain the modified phenazine polymer. Step S5: The modified phenazine polymer, conductive agent Ketjenblack EC300J, and binder Solvay PVDF were added. 6020 was mixed evenly at a mass ratio of 6:3:1, and then N-methylpyrrolidone was added to adjust the solid content to 40%. The mixture was then ground to form a slurry, which was coated onto the surface of an aluminum foil current collector. The slurry was then placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain a phenazine polymer cathode material for sodium-ion start-stop batteries.
[0024] Comparative Example 1: This comparative example is a method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, including the following steps: Step S1: 110 mmol of sodium dithionite, 60 mL of anhydrous ethanol and 150 mL of deionized water are added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas is introduced for protection, and the mixture is stirred for 30 min at a temperature of 25 °C and a stirring rate of 300 r / min. Then, 10 mmol of phenazine is added and the mixture is stirred for another 30 min. n, then the temperature was raised to 90℃ and the reaction was stirred for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature, then vacuum filtered, the filter cake was washed three times with distilled water, and then placed in a vacuum drying oven and dried at 90℃ for 6 hours to obtain dihydrophenazine; Step S2: 10 mmol dihydrophenazine, 10 mmol p-dibromobenzene, 0.5 g sodium tert-butoxide, 20 mg 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, 30 mg RuPhos Pd G2 catalyst and 80 mL xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred at 25 °C and 300 r / min for 30 min, then heated to 120 °C and stirred for another 48 h. After the reaction was completed, the product was cooled to room temperature and centrifuged. The precipitate was washed three times in sequence with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran. It was then placed in a vacuum drying oven and dried at 90 °C for 6 h to obtain the modified phenazine polymer. Step S3: The modified phenazine polymer, conductive agent Ketjenblack EC300J, and binder Solvay PVDF were added. 6020 was mixed evenly at a mass ratio of 6:3:1, and then N-methylpyrrolidone was added to adjust the solid content to 40%. After grinding, a slurry was formed and coated on the surface of an aluminum foil current collector. Then, it was placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain a phenazine polymer cathode material for sodium-ion start-stop batteries.
[0025] Comparative Example 2: This comparative example is a method for preparing a phenazine polymer positive electrode material for a sodium-ion start-stop battery, including the following steps: Step S1: 110 mmol of sodium dithionite, 60 mL of anhydrous ethanol, and 150 mL of deionized water are added to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Nitrogen gas is introduced for protection, and the mixture is stirred and reacted for 30 min at a temperature of 25 °C and a stirring rate of 300 r / min. Then, 10 mmol of phenazine is added, and the mixture is stirred and reacted for another 30 min. The reaction was then heated to 90°C and stirred for 5 hours. After the reaction was completed, the product was cooled to room temperature and then vacuum filtered. The filter cake was washed three times with distilled water and then placed in a vacuum drying oven and dried at 90°C for 6 hours to obtain dihydrophenazine. Step S2: 10 mmol of dihydrophenazine, 10 mmol of 2,7-dibromocarbazole, 0.5 g of sodium tert-butoxide, 20 mg of 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, and 30 mg of RuPhos Pd G2 catalyst and 80 mL xylene were added to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred at 25 °C and 300 r / min for 30 min, then heated to 120 °C and stirred for another 48 h. After the reaction was completed, the product was cooled to room temperature and centrifuged. The precipitate was washed three times in sequence with dichloromethane, distilled water, methanol, acetone, and tetrahydrofuran. It was then placed in a vacuum drying oven and dried at 90 °C for 6 h to obtain the modified phenazine polymer. Step S3: The modified phenazine polymer, conductive agent Ketjenblack EC300J, and binder Solvay PVDF were added. 6020 was mixed evenly at a mass ratio of 6:3:1, and then N-methylpyrrolidone was added to adjust the solid content to 40%. After grinding, a slurry was formed and coated on the surface of an aluminum foil current collector. Then, it was placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain a phenazine polymer cathode material for sodium-ion start-stop batteries.
[0026] Performance testing was conducted using phenazine polymer cathode material as the positive electrode, sodium sheet as the negative electrode, glass fiber membrane (GF / D, Whatman) as the separator, and 1M NaPF6 (EC:DEC:FEC=1:1:0.05, v / v / v) as the electrolyte to assemble CR-2032 coin cells into sodium-ion start-stop batteries of Examples 1-3 and Comparative Examples 1-2. The CR-2032 coin cells were tested for energy density and discharge specific capacity at a current density of 1 A / g, and capacity retention after 1000 cycles. The test results are shown in the table below.
[0027] Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-2, it can be seen that the phenazine polymer cathode material of this application has high energy density, discharge specific capacity, and capacity retention, indicating that it has excellent electrochemical performance.
[0028] In the description of this specification, references to terms such as "an embodiment," "example," "specific 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.
[0029] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.
Claims
1. A phenazine polymer cathode material for sodium-ion start-stop batteries, characterized in that, The product is prepared by grinding a modified phenazine polymer, a conductive agent, and a binder into a slurry, which is then coated onto the surface of an aluminum foil current collector and dried. The modified phenazine polymer is prepared by the following steps: Step a1: Sodium dithionite, anhydrous ethanol, and deionized water are stirred and reacted, then phenazine is added and the reaction continues with stirring. After the reaction is complete, the reaction product is cooled, then vacuum filtered, and the filter cake is washed and dried to obtain dihydrophenazine. Step a2: 1-pyrene methanol, potassium hydroxide, and tetrahydrofuran are stirred and reacted, then 1,4-dibromobutane is added dropwise and the reaction continues with stirring. After the reaction is complete, the reaction product is cooled, then poured into ice water, and then extracted. The liquid was washed, dried, and then vacuum filtered. The filtrate was then evaporated by rotary evaporation, followed by silica gel column chromatography and recrystallization to obtain a bromoalkylpyrene ring compound. Step a3: The bromoalkylpyrene ring compound, 2,7-dibromocarbazole, potassium hydroxide, and dimethyl sulfoxide were stirred and reacted. After the reaction was completed, the reaction product was poured into ice water and extracted. The extract was washed, dried, and then vacuum filtered. The filtrate was then evaporated by rotary evaporation, followed by silica gel column chromatography and recrystallization to obtain a pyrene ring-dibromocarbazole compound. Step a4: Dihydrophenazine, pyrene ring-dibromocarbazole compound, sodium tert-butoxide, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, RuPhos Pd G2 catalyst, and xylene were stirred and reacted. After the reaction was completed, the reaction product was cooled, centrifuged, and the precipitate was washed and dried to obtain a modified phenazine polymer.
2. The phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 1, characterized in that, The ratio of sodium dithionite, anhydrous ethanol, deionized water and phenazine in step a1 is 100-110 mmol: 50-60 mL: 130-150 mL: 10 mmol.
3. The phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 1, characterized in that, The ratio of 1-pyrene methanol, potassium hydroxide, tetrahydrofuran, and 1,4-dibromobutane used in step a2 is 20 mmol: 25-30 mmol: 50-60 mL: 20 mmol.
4. The phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 1, characterized in that, The ratio of the bromoalkylpyrene ring compound, 2,7-dibromocarbazole, potassium hydroxide, and dimethyl sulfoxide in step a3 is 13-15 mmol: 10 mmol: 30-40 mmol: 80-90 mL.
5. The phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 1, characterized in that, The ratio of dihydrophenazine, pyrene cyclodibromocarbazole compound, sodium tert-butoxide, 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl, RuPhos Pd G2 catalyst, and xylene in step a4 is 10 mmol: 10 mmol: 0.4-0.5 g: 15-20 mg: 20-30 mg: 60-80 mL.
6. A method for preparing a phenazine polymer cathode material for a sodium-ion start-stop battery, characterized in that, The preparation of the phenazine polymer cathode material for sodium-ion start-stop batteries as described in any one of claims 1-5 comprises the following steps: mixing a modified phenazine polymer, a conductive agent, and a binder uniformly; then adding N-methylpyrrolidone to adjust the solid content to 40%; subsequently grinding to form a slurry; coating the slurry onto the surface of an aluminum foil current collector; and then placing it in a vacuum drying oven and drying at 60°C for 12 hours to obtain a loading of 1.30 ± 0.05 mg / cm³. 2 Phenozine polymer cathode material for sodium-ion start-stop batteries.
7. The method for preparing the phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 6, characterized in that, The mass ratio of the modified phenazine polymer, the conductive agent, and the binder is 6:3:
1.
8. The method for preparing the phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 6, characterized in that, The conductive agent is Ketjenblack EC300J.
9. The method for preparing the phenazine polymer cathode material for sodium-ion start-stop batteries according to claim 6, characterized in that, The adhesive is Solvay PVDF 6020 from the USA.