Black phosphorus-based phosphorus-carbon composite negative electrode material and preparation method thereof
By preparing black phosphorus-based phosphorus-carbon composite anode materials, and using epoxy compounds and nanomaterials for doping and modification, combined with a polypyrrole coating layer, the problem of poor cycle stability of black phosphorus-based anode materials was solved, achieving high specific capacity and good electrochemical performance, making it suitable for large-scale production.
Patent Information
- Application Number
- CN202511453642.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2026-01-06
AI Technical Summary
Existing black phosphorus-based anode materials suffer from severe volume expansion during charge and discharge, are prone to side reactions with the electrolyte, leading to easy pulverization and detachment of the electrode material, rapid degradation of cycle performance, and poor cycle stability.
By preparing black phosphorus-based phosphorus-carbon composite anode material, epoxy groups are introduced through the reaction of pentaerythritol and epichlorohydrin, black phosphorus is mechanically exfoliated to form fine particulate powder, and then doped with nano-titanium dioxide and nano-graphite by ball milling. Combined with silane coupling agent modification, silver ions and long carbon chains are introduced to form a modified phosphorus-carbon composite. Finally, a polypyrrole layer is coated to enhance the interfacial bonding and conductivity.
It significantly improves the specific capacity and cycle life of lithium-ion batteries, ensures the stability of the battery during multiple charge and discharge cycles, enhances the cycle stability and conductivity of the material, and is suitable for mass production.
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Figure CN121282162A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of anode materials, specifically to a black phosphorus-based phosphorus-carbon composite anode material and its preparation method. Background Technology
[0002] With the rapid development of electric vehicles, portable electronic devices, and other fields, higher requirements are being placed on the energy density, cycle stability, and rate performance of lithium-ion batteries. As a key component of lithium-ion batteries, the performance of the anode material directly affects the overall performance of the battery.
[0003] Traditional graphite anode materials have a low theoretical specific capacity (372 mAh / g), making it difficult to meet the demands of high-energy-density batteries. Black phosphorus, as a novel two-dimensional material, possesses a unique layered structure and a high theoretical specific capacity (2596 mAh / g), and is considered a promising next-generation anode material. However, black phosphorus exhibits severe volume expansion during charge and discharge, is prone to side reactions with the electrolyte, leading to easy pulverization and detachment of the electrode material, rapid degradation of cycle performance, and poor cycle stability.
[0004] Therefore, developing a black phosphorus-based phosphorus-carbon composite anode material and its preparation method is of great practical significance. Summary of the Invention
[0005] In order to overcome the above-mentioned technical problems, the present invention aims to provide a black phosphorus-based phosphorus-carbon composite anode material and its preparation method, which solves the problems of poor electrochemical performance and poor cycle stability of existing black phosphorus-based anode materials.
[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, this application provides a black phosphorus-based phosphorus-carbon composite anode material, comprising a black phosphorus-based active material, a conductive agent, and a binder; The black phosphorus-based active material is prepared by the following steps: Step A1: Add pentaerythritol, epichlorohydrin, and tetrabutylammonium iodide to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir at 20-25°C and 200-300 r / min for 10-20 min. Then raise the temperature to 80-90°C and continue stirring for 6-7 h. Add sodium hydroxide solution and cool to 60-65°C and continue stirring for 4-5 h. After the reaction is complete, cool the reaction product to room temperature and add it to distilled water. Extract with anhydrous toluene 2-3 times, combine the extracts and dry with anhydrous sodium sulfate. Filter under vacuum, remove the solvent by rotary evaporation of the filtrate, and then place it in a vacuum drying oven and dry at 80-90°C for 2-3 h to obtain a polyepoxy compound. Step A2: Add black phosphorus and anhydrous ethanol to a three-necked flask equipped with a stirrer and thermometer. Sonicate at a frequency of 40-50 kHz for 30-50 min. Then mechanically peel off the precipitate at a temperature of 20-25℃ and a stirring rate of 2000-3000 r / min for 1-3 h. After centrifugation, wash the precipitate 2-3 times with hydrogen peroxide, hydrochloric acid solution and distilled water in sequence. Then place it in a vacuum drying oven and dry at a temperature of 60-70℃ for 5-6 h to obtain peeled black phosphorus powder. Step A3: Add the stripped black phosphorus powder, nano titanium dioxide, nano graphite, silver nitrate, silane coupling agent KH-550 and ethanol solution to a ball mill and ball mill for 8-10 hours at a ball-to-material ratio of 10-15:1 and a ball milling rate of 300-500 r / min. Then add the polyepoxy compound and continue ball milling for 1-2 hours. After that, place it in a vacuum drying oven and dry it at a temperature of 40-45℃ for 5-6 hours to obtain the modified phosphorus-carbon composite. Step A4: Add pyrrole, 1-bromooctane, anhydrous potassium carbonate, and anhydrous diethyl ether to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir the reaction at 20-25°C and 200-300 r / min for 20-30 min. Then, heat to reflux and continue stirring for 5-6 h. After the reaction is complete, cool the reaction product to room temperature, then filter under vacuum. Remove the solvent by rotary evaporation of the filtrate, and then purify it by silica gel column chromatography with a mixed solvent to obtain long-linked branched pyrrole. Step A5: Add the modified phosphorus-carbon composite, sodium benzenesulfonate, and deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0-5℃ and 200-300 r / min for 1-1.5 h. Then add pyrrole, long-linked branched pyrrole, and ferric chloride solution and continue stirring for 10-15 h. After the reaction is complete, centrifuge the reaction product and wash the precipitate 2-3 times with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry it at 50-60℃ for 8-10 h to obtain black phosphorus-based active material.
[0007] In a preferred embodiment of the present invention, the ratio of pentaerythritol, epichlorohydrin, tetrabutylammonium iodide and sodium hydroxide solution in step A1 is 10 mmol: 80-100 mmol: 0.03-0.05 g: 50-60 mL.
[0008] In a preferred embodiment of the present invention, the sodium hydroxide solution in step A1 has a mass fraction of 25-30%.
[0009] In a preferred embodiment of the present invention, the ratio of black phosphorus to anhydrous ethanol in step A2 is 1g:80-90mL.
[0010] In a preferred embodiment of the present invention, the hydrogen peroxide in step A2 has a mass fraction of 25-30%; and the hydrochloric acid solution has a mass fraction of 3-5%.
[0011] In a preferred embodiment of the present invention, the ratio of the amount of stripped black phosphorus powder, nano titanium dioxide, nano graphite, silver nitrate, silane coupling agent KH-550 and ethanol solution in step A3 is 5g:1-1.2g:2-2.5g:0.3-0.5g:0.9-2.1g:15-20mL.
[0012] In a preferred embodiment of the present invention, the average particle size of the nano-titanium dioxide in step A3 is 20 nm; the average particle size of the nano-graphite is 100 nm; and the volume fraction of the ethanol solution is 75-85%.
[0013] In a preferred embodiment of the present invention, the ratio of pyrrole, 1-bromooctane, anhydrous potassium carbonate and anhydrous diethyl ether in step A4 is 10 mmol: 10 mmol: 12-15 mmol: 60-70 mL.
[0014] In a preferred embodiment of the present invention, the mixed solvent in step A4 is a mixture of petroleum ether and ethyl acetate in a volume ratio of 10-12:1.
[0015] In a preferred embodiment of the present invention, the ratio of the modified phosphorus-carbon complex, sodium benzenesulfonate, deionized water, pyrrole, long-linked branched pyrrole, and ferric chloride solution in step A5 is 3g:0.2-0.3g:40-45mL:0.5-0.7g:1.2-1.6g:20-30mL.
[0016] In a preferred embodiment of the present invention, the mass fraction of the ferric chloride solution in step A5 is 3-5%.
[0017] Secondly, this application provides a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step 1: Weigh out the black phosphorus-based active material, conductive agent, and binder according to the mass ratio, and set aside; Step 2: Mix the black phosphorus-based active material, conductive agent, and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material.
[0018] In a preferred embodiment of the present invention, the mass ratio of the black phosphorus-based active material, the conductive agent, and the binder is 8:1:1.
[0019] In a preferred embodiment of the present invention, the conductive agent is acetylene black.
[0020] In a preferred embodiment of the present invention, the adhesive is polyvinylidene fluoride (PVDF) Solvay HR460 from France.
[0021] Compared with the prior art, the beneficial effects of the present invention are: In the preparation of black phosphorus-based phosphorus-carbon composite anode material, a black phosphorus-based active material was first prepared. This involved the reaction of pentaerythritol and epichlorohydrin, where the hydroxyl groups on pentaerythritol reacted with epichlorohydrin through a ring-opening and ring-closing reaction, introducing a large number of epoxy groups to obtain a polyepoxy compound. Black phosphorus was then mechanically exfoliated to form fine particles, yielding exfoliated black phosphorus powder. This exfoliated black phosphorus powder, nano-titanium dioxide, nano-graphite, and silver nitrate were then ball-milled and doped to achieve sufficient doping of the exfoliated black phosphorus powder with nano-titanium dioxide and nano-graphite, while also introducing a large number of silver ions. Simultaneously, under the action of the silane coupling agent KH-550... This process modifies each particle, introduces amino groups, and utilizes the reaction between the epoxy groups on the polyepoxy compounds and the amino groups to achieve epoxy grafting and cross-linking between particles. This results in fully refined and tightly connected particles, yielding a modified phosphorus-carbon composite. A reaction between pyrrole and 1-bromooctane is then used, where the secondary amino groups on the pyrrole react with the bromine atoms on the 1-bromooctane, introducing long carbon chains and resulting in long-chain branched pyrrole. Finally, pyrrole and the long-chain branched pyrrole are used as monomers to form polypyrrole containing long carbon chains, which coats the surface of the modified phosphorus-carbon composite, yielding a black phosphorus-based active material. This black phosphorus-based active material uses black phosphorus as the core active material. This material possesses high theoretical specific capacity. Through compositing with nano-titanium dioxide and nano-graphite, the nano-titanium dioxide exhibits a high voltage plateau, excellent cycle stability, and small volume deformation. The combination of these three materials fully leverages their advantages, resulting in a composite material with high specific capacity and cycle stability. Adding silver ions further enhances its conductivity. Modification with silane coupling agent KH-550 and polyepoxy compounds improves the composite material's density, thus firmly binding the components together, strengthening interfacial bonding, facilitating lithium-ion transport, and forming an organic protective layer, further enhancing its properties. The resulting polypyrrole exhibits excellent electrical conductivity, further enhancing the electrochemical performance of the composite material. Simultaneously, the secondary amine groups in its molecular structure react with the grafted epoxy groups on the composite material, preventing the polypyrrole coating from detaching and forming an excellent elastic buffer structure that suppresses volume expansion, significantly improving its cycle stability. Furthermore, the long carbon chains in its molecular structure endow the polypyrrole segments with good flexibility, allowing them to absorb stress through segment slippage during volume changes. This also imparts excellent hydrophobic properties, enhancing its chemical stability. Additionally, its good compatibility with the electrolyte improves the wettability of the composite material with the electrolyte.
[0022] The volume change of black phosphorus-based active materials enables multi-level buffering and synergistic cooperation of multiple conductive materials, which helps to facilitate the rapid transport of lithium ions. Using black phosphorus-based phosphorus-carbon composite anode materials as the main raw material can significantly improve the specific capacity and cycle life of lithium-ion batteries, ensure the stability of the battery during multiple charge-discharge processes, and ensure excellent battery performance. At the same time, the preparation method is simple, easy to master, suitable for large-scale production, and has good economic benefits and market prospects. Attached Figure Description
[0023] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0024] Figure 1 This is a schematic diagram showing the electrochemical test results of the black phosphorus-based phosphorus-carbon composite anode materials of Examples 1-3 and Comparative Examples 1-5 of the present invention. Detailed Implementation
[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of 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 skilled in the art without creative effort are within the scope of protection of the present invention. Example 1:
[0026] This embodiment describes a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, including the following steps: Step S1: 10 mmol pentaerythritol, 80 mmol epichlorohydrin and 0.03 g tetrabutylammonium iodide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 20 °C and 200 r / min for 10 min. Then the temperature was raised to 80 °C and the mixture was stirred for 6 h. Then 50 mL of 25% sodium hydroxide solution was added and the temperature was lowered to 60 °C and the mixture was stirred for 4 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to distilled water. The product was then extracted twice with anhydrous toluene. The extracts were combined and dried with anhydrous sodium sulfate. The product was then vacuum filtered and the solvent was removed by rotary evaporation. The product was then placed in a vacuum drying oven and dried at 80 °C for 2 h to obtain a polyepoxy compound. Step S2: Add 1g of black phosphorus and 80mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate the mixture at a frequency of 40kHz for 30min. Then, mechanically peel the mixture at a temperature of 20℃ and a stirring rate of 2000r / min for 1h. After centrifugation, wash the precipitate twice with 25% hydrogen peroxide, 3% hydrochloric acid solution, and distilled water. Then, place the precipitate in a vacuum drying oven and dry it at a temperature of 60℃ for 5h to obtain peeled black phosphorus powder. Step S3: Add 5g of stripped black phosphorus powder, 1g of nano-titanium dioxide with an average particle size of 20nm, 2g of nano-graphite with an average particle size of 100nm, 0.3g of silver nitrate, 0.9g of silane coupling agent KH-550, and 15mL of 75% ethanol solution to a ball mill. Ball mill for 8h at a ball-to-material ratio of 10:1 and a ball milling rate of 300r / min. Then add a polyepoxy compound and continue ball milling for 1h. After that, place it in a vacuum drying oven and dry it at 40℃ for 5h to obtain the modified phosphorus-carbon composite. Step S4: 10 mmol pyrrole, 10 mmol 1-bromooctane, 12 mmol anhydrous potassium carbonate and 60 mL anhydrous diethyl ether were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 20 °C and 200 r / min for 20 min. Then the temperature was raised to reflux and the mixture was stirred for another 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then purified by silica gel column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain long-linked branched pyrrole. Step S5: Add 3g of modified phosphorus-carbon composite, 0.2g of sodium benzenesulfonate and 40mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the mixture at 0℃ and 200r / min for 1h. Then add 0.5g of pyrrole, 1.2g of long-linked branched pyrrole and 20mL of 3% ferric chloride solution and continue stirring for 10h. After the reaction is complete, centrifuge the reaction product and wash the precipitate twice with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry it at 50℃ for 8h to obtain black phosphorus-based active material. Step S6: Weigh out the black phosphorus-based active material, conductive agent, and binder in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France. Step S7: Mix the black phosphorus-based active material, conductive agent and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material. Example 2:
[0027] This embodiment describes a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, including the following steps: Step S1: 10 mmol pentaerythritol, 90 mmol epichlorohydrin and 0.04 g tetrabutylammonium iodide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 22 °C and 250 r / min for 15 min. Then the temperature was raised to 85 °C and the mixture was stirred for 6.5 h. Then 55 mL of 28% sodium hydroxide solution was added and the temperature was lowered to 62 °C and the mixture was stirred for 4.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to distilled water. The product was then extracted twice with anhydrous toluene. The extracts were combined and dried with anhydrous sodium sulfate. The product was then vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The product was then placed in a vacuum drying oven and dried at 85 °C for 2.5 h to obtain a polyepoxy compound. Step S2: Add 1g of black phosphorus and 85mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate the mixture at a frequency of 45kHz for 40min. Then, mechanically peel the mixture at a temperature of 22℃ and a stirring rate of 2500r / min for 2h. After centrifugation, wash the precipitate twice with 28% hydrogen peroxide, 4% hydrochloric acid solution, and distilled water. Then, place the precipitate in a vacuum drying oven and dry it at a temperature of 65℃ for 5.5h to obtain peeled black phosphorus powder. Step S3: Add 5g of stripped black phosphorus powder, 1.1g of nano-titanium dioxide with an average particle size of 20nm, 2.2g of nano-graphite with an average particle size of 100nm, 0.4g of silver nitrate, 1.5g of silane coupling agent KH-550, and 18mL of 80% ethanol solution to a ball mill. Ball mill for 9h at a ball-to-material ratio of 12:1 and a ball milling rate of 400r / min. Then add a polyepoxy compound and continue ball milling for 1.5h. After that, place it in a vacuum drying oven and dry it at 42℃ for 5.5h to obtain the modified phosphorus-carbon composite. Step S4: 10 mmol pyrrole, 10 mmol 1-bromooctane, 14 mmol anhydrous potassium carbonate and 65 mL anhydrous diethyl ether were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 22 °C and 250 r / min for 25 min. Then the temperature was raised to reflux and the mixture was stirred for another 5.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then purified by silica gel column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 11:1 to obtain long-linked branched pyrrole. Step S5: Add 3g of modified phosphorus-carbon composite, 0.25g of sodium benzenesulfonate and 42mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir and react for 1.2h at 3℃ and 250r / min. Then add 0.6g of pyrrole, 1.4g of long-linked branched pyrrole and 25mL of 4% ferric chloride solution and continue stirring and reacting for 12h. After the reaction is completed, centrifuge the reaction product and wash the precipitate twice with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry at 52℃ for 9h to obtain black phosphorus-based active material. Step S6: Weigh out the black phosphorus-based active material, conductive agent, and binder in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France. Step S7: Mix the black phosphorus-based active material, conductive agent and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material. Example 3:
[0028] This embodiment describes a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, including the following steps: Step S1: 10 mmol pentaerythritol, 100 mmol epichlorohydrin and 0.05 g tetrabutylammonium iodide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 20 min. The temperature was then raised to 90 °C and the mixture was stirred for 7 h. 60 mL of 30% sodium hydroxide solution was added and the mixture was cooled to 65 °C and stirred for 5 h. After the reaction was completed, the product was cooled to room temperature and added to distilled water. The product was then extracted three times with anhydrous toluene. The extracts were combined and dried with anhydrous sodium sulfate. The product was then vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The product was then placed in a vacuum drying oven and dried at 90 °C for 3 h to obtain a polyepoxy compound. Step S2: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate at a frequency of 50kHz for 50min. Then mechanically peel off the precipitate at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution and distilled water. Then place it in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S3: Add 5g of stripped black phosphorus powder, 1.2g of nano-titanium dioxide with an average particle size of 20nm, 2.5g of nano-graphite with an average particle size of 100nm, 0.5g of silver nitrate, 2.1g of silane coupling agent KH-550, and 20mL of 85% ethanol solution to a ball mill. Ball mill for 10h at a ball-to-material ratio of 15:1 and a ball milling rate of 500r / min. Then add a polyepoxy compound and continue ball milling for 2h. After that, place it in a vacuum drying oven and dry it at 45℃ for 6h to obtain the modified phosphorus-carbon composite. Step S4: 10 mmol pyrrole, 10 mmol 1-bromooctane, 15 mmol anhydrous potassium carbonate and 70 mL anhydrous diethyl ether were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 30 min. Then the temperature was raised to reflux and the mixture was stirred for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then purified by silica gel column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 12:1 to obtain long-linked branched pyrrole. Step S5: Add 3g of modified phosphorus-carbon composite, 0.3g of sodium benzenesulfonate and 45mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the mixture at 5℃ and 300r / min for 1.5h. Then add 0.7g of pyrrole, 1.6g of long-linked branched pyrrole and 30mL of 5% ferric chloride solution and continue stirring for 15h. After the reaction is complete, centrifuge the reaction product and wash the precipitate three times with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry it at 60℃ for 10h to obtain black phosphorus-based active material. Step S6: Weigh out the black phosphorus-based active material, conductive agent, and binder in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France. Step S7: Mix the black phosphorus-based active material, conductive agent and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material.
[0029] Comparative Example 1: This comparative example illustrates a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step S1: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate the mixture at a frequency of 50kHz for 50min. Then, mechanically peel the mixture at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution, and distilled water. Then, place the precipitate in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S2: Weigh out the stripping black phosphorus powder, conductive agent, and adhesive in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the adhesive is polyvinylidene fluoride (PVDF) Solvay HR460 from France; Step S3: Mix the stripped black phosphorus powder, conductive agent and binder evenly to obtain black phosphorus-based phosphorus-carbon composite anode material.
[0030] Comparative Example 2: This comparative example illustrates a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step S1: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate the mixture at a frequency of 50kHz for 50min. Then, mechanically peel the mixture at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution, and distilled water. Then, place the precipitate in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S2: Add 5g of stripped black phosphorus powder, 1.2g of nano-titanium dioxide with an average particle size of 20nm, 2.5g of nano-graphite with an average particle size of 100nm, 0.5g of silver nitrate and 20mL of 85% ethanol solution to a ball mill. Ball mill for 10h at a ball-to-material ratio of 15:1 and a ball milling rate of 500r / min. Then place it in a vacuum drying oven and dry it at 45℃ for 6h to obtain the modified phosphorus-carbon composite. Step S3: Weigh the modified phosphorus-carbon composite, conductive agent, and binder according to a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France; Step S4: Mix the modified phosphorus-carbon composite, conductive agent and binder evenly to obtain black phosphorus-based phosphorus-carbon composite anode material.
[0031] Comparative Example 3: This comparative example illustrates a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step S1: 10 mmol pentaerythritol, 100 mmol epichlorohydrin and 0.05 g tetrabutylammonium iodide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 20 min. The temperature was then raised to 90 °C and the mixture was stirred for 7 h. 60 mL of 30% sodium hydroxide solution was added and the mixture was cooled to 65 °C and stirred for 5 h. After the reaction was completed, the product was cooled to room temperature and added to distilled water. The product was then extracted three times with anhydrous toluene. The extracts were combined and dried with anhydrous sodium sulfate. The product was then vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The product was then placed in a vacuum drying oven and dried at 90 °C for 3 h to obtain a polyepoxy compound. Step S2: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate at a frequency of 50kHz for 50min. Then mechanically peel off the precipitate at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution and distilled water. Then place it in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S3: Add 5g of stripped black phosphorus powder, 1.2g of nano-titanium dioxide with an average particle size of 20nm, 2.5g of nano-graphite with an average particle size of 100nm, 0.5g of silver nitrate, 2.1g of silane coupling agent KH-550, and 20mL of 85% ethanol solution to a ball mill. Ball mill for 10h at a ball-to-material ratio of 15:1 and a ball milling rate of 500r / min. Then add a polyepoxy compound and continue ball milling for 2h. After that, place it in a vacuum drying oven and dry it at 45℃ for 6h to obtain the modified phosphorus-carbon composite. Step S4: Weigh the modified phosphorus-carbon composite, conductive agent, and binder according to a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France; Step S5: Mix the modified phosphorus-carbon composite, conductive agent and binder evenly to obtain black phosphorus-based phosphorus-carbon composite anode material.
[0032] Comparative Example 4: This comparative example illustrates a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step S1: 10 mmol pentaerythritol, 100 mmol epichlorohydrin and 0.05 g tetrabutylammonium iodide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 20 min. The temperature was then raised to 90 °C and the mixture was stirred for 7 h. 60 mL of 30% sodium hydroxide solution was added and the mixture was cooled to 65 °C and stirred for 5 h. After the reaction was completed, the product was cooled to room temperature and added to distilled water. The product was then extracted three times with anhydrous toluene. The extracts were combined and dried with anhydrous sodium sulfate. The product was then vacuum filtered. The solvent was removed by rotary evaporation of the filtrate. The product was then placed in a vacuum drying oven and dried at 90 °C for 3 h to obtain a polyepoxy compound. Step S2: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate at a frequency of 50kHz for 50min. Then mechanically peel off the precipitate at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution and distilled water. Then place it in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S3: Add 5g of stripped black phosphorus powder, 1.2g of nano-titanium dioxide with an average particle size of 20nm, 2.5g of nano-graphite with an average particle size of 100nm, 0.5g of silver nitrate, 2.1g of silane coupling agent KH-550, and 20mL of 85% ethanol solution to a ball mill. Ball mill for 10h at a ball-to-material ratio of 15:1 and a ball milling rate of 500r / min. Then add a polyepoxy compound and continue ball milling for 2h. After that, place it in a vacuum drying oven and dry it at 45℃ for 6h to obtain the modified phosphorus-carbon composite. Step S4: Add 3g of modified phosphorus-carbon composite, 0.3g of sodium benzenesulfonate and 45mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir the mixture at 5℃ and 300r / min for 1.5h. Then add 0.7g of pyrrole and 30mL of 5% ferric chloride solution and continue stirring for 15h. After the reaction is complete, centrifuge the reaction product and wash the precipitate three times with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry it at 60℃ for 10h to obtain black phosphorus-based active material. Step S5: Weigh out the black phosphorus-based active material, conductive agent, and binder in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France; Step S6: Mix the black phosphorus-based active material, conductive agent and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material.
[0033] Comparative Example 5: This comparative example illustrates a method for preparing a black phosphorus-based phosphorus-carbon composite anode material, comprising the following steps: Step S1: Add 1g of black phosphorus and 90mL of anhydrous ethanol to a three-necked flask equipped with a stirrer and a thermometer. Sonicate the mixture at a frequency of 50kHz for 50min. Then, mechanically peel the mixture at a temperature of 25℃ and a stirring rate of 3000r / min for 3h. After centrifugation, wash the precipitate three times in sequence with 30% hydrogen peroxide, 5% hydrochloric acid solution, and distilled water. Then, place the precipitate in a vacuum drying oven and dry it at a temperature of 70℃ for 6h to obtain peeled black phosphorus powder. Step S2: 10 mmol pyrrole, 10 mmol 1-bromooctane, 15 mmol anhydrous potassium carbonate and 70 mL anhydrous diethyl ether were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 30 min. Then the temperature was raised to reflux and the mixture was stirred for 6 h. After the reaction was completed, the reaction product was cooled to room temperature and then filtered under vacuum. The solvent was removed by rotary evaporation of the filtrate. The filtrate was then purified by silica gel column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 12:1 to obtain long-linked branched pyrrole. Step S3: Add 3g of stripped black phosphorus powder, 0.3g of sodium benzenesulfonate and 45mL of deionized water to a three-necked flask equipped with a stirrer and thermometer. Stir and react for 1.5h at 5℃ and 300r / min. Then add 0.7g of pyrrole, 1.6g of long-linked branched pyrrole and 30mL of 5% ferric chloride solution and continue stirring and reacting for 15h. After the reaction is completed, centrifuge the reaction product and wash the precipitate three times with anhydrous ethanol and distilled water. Then place it in a vacuum drying oven and dry at 60℃ for 10h to obtain black phosphorus-based active material. Step S4: Weigh out the black phosphorus-based active material, conductive agent, and binder in a mass ratio of 8:1:1, and set aside; wherein the conductive agent is acetylene black, and the binder is polyvinylidene fluoride (PVDF) Solvay HR460 from France; Step S5: Mix the black phosphorus-based active material, conductive agent and binder evenly to obtain the black phosphorus-based phosphorus-carbon composite anode material.
[0034] Performance testing The black phosphorus-based phosphorus-carbon composite anode materials of Examples 1-3 and Comparative Examples 1-5 were added to N-methylpyrrolidone with a solid content of 50% and stirred for 40 minutes at a temperature of 30°C and a stirring rate of 1000 r / min to obtain the anode slurry. The negative electrode slurry is coated onto copper foil to form a coating with a thickness of 100 μm. Then it is placed in a vacuum drying oven and dried at a temperature of 80℃ for 12 hours. After that, it is cut into round copper sheets to obtain the negative electrode sheet. A CR2025 coin cell was assembled from a negative electrode, a positive electrode (lithium sheet), a separator (Celgard 2400), and an electrolyte [1M LiPF6 (EC:DEC:DMC=1:1:1, v / v / v)]. After standing for 12 hours, electrochemical tests were performed at a current density of 100 mA / g. The test results are as follows: Figure 1 As shown.
[0035] See Figure 1 As shown, based on the comparison between Examples 1-3 and Comparative Examples 1-5, it can be seen that doping with nano-titanium dioxide, nano-graphite and silver nitrate can ensure the discharge specific capacity of black phosphorus and improve its cycle stability. After being encapsulated with polypyrrole, the discharge specific capacity and cycle stability can be further improved.
[0036] 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.
[0037] 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 black phosphorus-based phosphorus-carbon composite negative electrode material, characterized in that, The black phosphorus-based active material, a conductive agent, and a binder are included. The black phosphorus-based active material is prepared by the following steps: Step A1: pentaerythritol, epichlorohydrin, and tetrabutylammonium iodide are stirred and reacted, then sodium hydroxide solution is added for continuous stirring and reaction, after the reaction is completed, the reaction product is cooled, then added to distilled water, then extracted, the combined extract is dried, then vacuum filtered, the filtrate is rotary evaporated, and a polyeoxy compound is obtained; Step A2: black phosphorus and anhydrous ethanol are ultrasonically treated, then mechanically peeled, centrifuged, the precipitate is washed and dried, and a peeled black phosphorus powder is obtained; Step A3: the peeled black phosphorus powder, nano-titanium dioxide, nano-graphite, silver nitrate, silane coupling agent KH-550, and an ethanol solution are ball milled, then the polyeoxy compound is added for continuous ball milling, then dried, and a modified phosphorus-carbon composite is obtained; Step A4: pyrrole, 1-bromo octane, anhydrous potassium carbonate, and anhydrous diethyl ether are stirred and reacted, after the reaction is completed, the reaction product is cooled, then vacuum filtered, the filtrate is rotary evaporated, then purified by silica gel column chromatography with a mixed solvent, and a long-chain branched pyrrole is obtained; Step A5: the modified phosphorus-carbon composite, sodium benzenesulfonate, and deionized water are stirred and reacted, then pyrrole, long-chain branched pyrrole, and a ferric chloride solution are added for continuous stirring and reaction, after the reaction is completed, the reaction product is centrifuged, the precipitate is washed and dried, and a black phosphorus-based active material is obtained. 2.The black phosphorus-based phosphorus-carbon composite negative electrode material of claim 1, characterized in that, The amount ratio of the pentaerythritol, epichlorohydrin, tetrabutylammonium iodide, and sodium hydroxide solution in step A1 is 10 mmol: 80-100 mmol: 0.03-0.05 g: 50-60 mL; and the mass fraction of the sodium hydroxide solution is 25-30%. 3.The black phosphorus-based phosphorus-carbon composite negative electrode material of claim 1, characterized in that, The amount ratio of the black phosphorus and anhydrous ethanol in step A2 is 1 g: 80-90 mL. 4.The black phosphorus-based phosphorus-carbon composite negative electrode material of claim 1, characterized in that, The amount ratio of the peeled black phosphorus powder, nano-titanium dioxide, nano-graphite, silver nitrate, silane coupling agent KH-550, and ethanol solution in step A3 is 5 g: 1-1.2 g: 2-2.5 g: 0.3-0.5 g: 0.9-2.1 g: 15-20 mL; the average particle size of the nano-titanium dioxide is 20 nm; the average particle size of the nano-graphite is 100 nm; and the volume fraction of the ethanol solution is 75-85%. 5.The black phosphorus-based phosphorus-carbon composite negative electrode material of claim 1, characterized in that, The amount ratio of the pyrrole, 1-bromo octane, anhydrous potassium carbonate, and anhydrous diethyl ether in step A4 is 10 mmol: 10 mmol: 12-15 mmol: 60-70 mL; and the mixed solvent is a mixture of petroleum ether and ethyl acetate in a volume ratio of 10-12:
1. 6.The black phosphorus-based phosphorus-carbon composite negative electrode material of claim 1, characterized in that, The amount ratio of the modified phosphorus-carbon composite, sodium benzenesulfonate, deionized water, pyrrole, long-chain branched pyrrole, and a ferric chloride solution in step A5 is 3 g: 0.2-0.3 g: 40-45 mL: 0.5-0.7 g: 1.2-1.6 g: 20-30 mL; and the mass fraction of the ferric chloride solution is 3-5%.
7. A method for preparing the black phosphorus-based phosphorus-carbon composite negative electrode material according to any one of claims 1-6, characterized in that, The following steps are included: Step one: black phosphorus-based active material, conductive agent, and binder are weighed according to the mass ratio, and standby; Step two: the black phosphorus-based active material, the conductive agent and the binder are mixed uniformly to obtain a black phosphorus-based phosphorus-carbon composite negative electrode material.
8. The preparation method of the black phosphorus-based phosphorus-carbon composite negative electrode material according to claim 7, characterized in that, The mass ratio of the black phosphorus-based active material, the conductive agent and the binder is 8:1:
1.
9. The preparation method of the black phosphorus-based phosphorus-carbon composite negative electrode material according to claim 7, characterized in that, The conductive agent is acetylene black.
10. The method for preparing a black phosphorus-based phosphorus-carbon composite anode material according to claim 7, characterized in that, The binder is polyvinylidene fluoride.