Black phosphorus composite negative electrode material and preparation method and application thereof

Abstract

The invention discloses a black phosphorus composite negative electrode material and a preparation method and application thereof. Comprising the following steps: mixing black phosphorus powder with a nitrogen-containing compound, performing high-temperature calcination in an inert gas protection environment, and performing natural cooling to obtain nitrogen-doped black phosphorus; the preparation method comprises the following steps: reacting 3, 4-ethylenedioxythiophene with perfluorooctyl ethyl acrylate in the presence of an oxidizing agent under an ice bath condition to synthesize a conductive hydrophobic polymer monomer; dispersing nitrogen-doped black phosphorus, and adding an initiator to initiate an in-situ polymerization reaction; and after the reaction is finished, centrifuging, washing and drying to obtain the conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material. The tight coating layer formed by the conductive hydrophobic polymer in the material isolates the contact between the nitrogen-doped black phosphorus and external air and moisture, prevents potential safety hazards caused by oxidation and hydrolysis, and further reduces the influence of moisture on the black phosphorus negative electrode; and moreover, a physical barrier effect is achieved in the battery, the growth of lithium dendrites is inhibited, and the use safety of the battery is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials and relates to a black phosphorus composite negative electrode material and a preparation method and application thereof. Background Art

[0002] In the current field of energy storage, the portability and intelligence of electronic products and the vigorous development of the electric vehicle industry have led to an explosive growth in the demand for high-performance batteries. Black phosphorus, with its significant advantage of high theoretical specific capacity, has become a hot topic in the research of negative electrode materials. However, black phosphorus materials have inherent deficiencies: they are easily oxidized in the air and have poor stability; the large volume changes during charging and discharging make it difficult for their cycle performance to meet the needs of practical applications. Although coating treatment is currently widely used to improve the performance of black phosphorus, traditional coating methods have technical bottlenecks such as uneven coating and weak interfacial bonding, which cannot fundamentally improve the comprehensive performance of black phosphorus negative electrode materials. Therefore, the development of a new method for preparing black phosphorus negative electrode materials is urgent, which is of vital practical significance for promoting the innovation of battery technology.

[0003] After searching the existing patent literature, it was found that CN112018363 A discloses a black phosphorus-based composite negative electrode material; a black phosphorus-carbon modified composite material is first formed, and then a conductive polymer is coated on the surface of the black phosphorus-carbon modified composite material by liquid phase in situ polymerization, thereby obtaining the desired black phosphorus-based composite negative electrode material. Among them, the polymer produced by liquid phase in situ polymerization can continuously or uniformly coat the black phosphorus-carbon modified composite material, or can discontinuously or non-uniformly coat the black phosphorus-carbon modified composite material, preferably continuously. However, even if this solution is continuously coated, it still fails to truly isolate the black phosphorus-based composite negative electrode material from the outside air and moisture, and to a certain extent, there are still safety hazards caused by oxidation and hydrolysis. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a black phosphorus composite negative electrode material and a preparation method and use thereof.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention relates to a method for preparing a black phosphorus composite negative electrode material; the method comprises the following steps:

[0007] S1. In the presence of an oxidant and in an ice bath, 3,4-ethylenedioxythiophene and perfluorooctylethyl acrylate are reacted to synthesize a conductive hydrophobic polymer monomer;

[0008] S2. Dispersing nitrogen-doped black phosphorus in the conductive hydrophobic polymer monomer solution obtained in S1, adding an initiator to initiate an in-situ polymerization reaction; after the reaction, centrifuging, washing, and drying to obtain a conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material, i.e., the black phosphorus composite negative electrode material.

[0009] As an embodiment of the present invention, in S1, the oxidant is at least one of ammonium persulfate, ferric chloride, and hydrogen peroxide.

[0010] As an embodiment of the present invention, in S1, the theoretical molar ratio of 3,4-ethylenedioxythiophene to perfluorooctyl ethyl acrylate is (1.5-2.5):1.

[0011] As an embodiment of the present invention, in S1, the ice bath reaction time is 5 to 8 hours.

[0012] As one embodiment of the present invention, the preparation of the nitrogen-doped black phosphorus includes: fully mixing black phosphorus powder with a nitrogen-containing compound, calcining at high temperature in an inert gas protection environment, and then naturally cooling to obtain the nitrogen-doped black phosphorus.

[0013] As an embodiment of the present invention, the nitrogen-containing compound is selected from at least one of melamine and ammonium carbonate.

[0014] As one embodiment of the present invention, black phosphorus powder and a nitrogen-containing compound are mixed in a P:N molar ratio of 1:0.6 to 1:1. Excessive nitrogen atoms attempting to incorporate into the black phosphorus lattice may not be able to enter uniformly and regularly due to the limited lattice capacity, resulting in more defects in the lattice. Insufficient nitrogen doping will not significantly improve the material's conductivity, electrochemical activity, etc. Therefore, it is preferred that the black phosphorus powder and the nitrogen-containing compound be mixed in a P:N molar ratio of 1:0.6 to 1:1.

[0015] As an embodiment of the present invention, the high temperature calcination is to increase the temperature to 800-850° C. at a heating rate of 5-7° C. / min and keep the temperature for 3-5 hours.

[0016] In one embodiment of the present invention, in S2, the mass ratio of nitrogen-doped black phosphorus to the conductive hydrophobic polymer monomer solution is 4-8:1. Excessive nitrogen-doped black phosphorus makes it difficult to evenly disperse in the conductive hydrophobic polymer monomer solution, and agglomeration is likely to occur. A too small ratio can hinder the full electrochemical performance. Therefore, in the present invention, the mass ratio of nitrogen-doped black phosphorus to the conductive hydrophobic polymer monomer solution is selected to be 4-8:1.

[0017] As an embodiment of the present invention, in S2, the initiator comprises azobisisobutyronitrile.

[0018] As an embodiment of the present invention, in S2, the mass ratio of the initiator to the conductive hydrophobic polymer monomer solution is 1:10-12.

[0019] As an embodiment of the present invention, in S2, the temperature of the in-situ polymerization reaction is 50-70°C, and the reaction time is 10-14 hours.

[0020] As an embodiment of the present invention, in S2, the centrifugation parameters are: rotation speed: 8000-1000 rpm, time: 10-15 minutes, temperature: 25±5°C.

[0021] As an embodiment of the present invention, in S2, the washing is washing with anhydrous ethanol 2 to 5 times.

[0022] As an embodiment of the present invention, in S2, the drying is vacuum drying at 60-70°C for 10-14 hours.

[0023] In some implementation examples, a method for preparing a black phosphorus composite negative electrode material is provided; the method comprises the following steps:

[0024] S1. Preparation of nitrogen-doped black phosphorus: Accurately weigh black phosphorus powder and nitrogen-containing compounds (such as melamine) and mix them thoroughly in a specific ratio. The mixture is placed in an environment tightly protected by inert gas and reacted under precisely controlled temperature and time conditions using high-temperature calcination technology to successfully prepare nitrogen-doped black phosphorus. During this process, high-temperature calcination promotes the uniform incorporation of nitrogen atoms into the black phosphorus lattice, effectively improving the electronic structure and electrical properties of black phosphorus.

[0025] S2. Synthesis of Conductive Hydrophobic Polymers: Monomers with unique structures and properties, such as 3,4-ethylenedioxythiophene (C6H6O2S) and fluorinated acrylates (perfluorooctylethyl acrylate C13H7F17O2), were selected as raw materials and synthesized using a chemical oxidative polymerization method. During the reaction, precise control of reaction conditions, such as temperature, reaction time, and the amount of oxidant (ammonium persulfate), allowed precise regulation of the polymer structure and properties, resulting in the successful synthesis of a conductive hydrophobic polymer monomer with both excellent conductivity and hydrophobicity.

[0026] S3, in-situ coating: The prepared nitrogen-doped black phosphorus is evenly dispersed in a solution system containing a conductive hydrophobic polymer monomer, and an appropriate amount of initiator (azobisisobutyronitrile, AIBN) is added to initiate an in-situ polymerization reaction under specific conditions such as temperature and stirring speed. During the polymerization process, the conductive hydrophobic polymer monomer gradually polymerizes and grows on the surface of the nitrogen-doped black phosphorus, achieving a uniform and tight in-situ coating of the nitrogen-doped black phosphorus, ultimately obtaining a high-performance conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material.

[0027] The black phosphorus composite negative electrode material prepared by the method of the present invention and its use in battery preparation also fall within the protection scope of the present invention.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) Improve battery energy density: Nitrogen doping optimizes the electron transmission path of black phosphorus, giving it higher electrical conductivity, thereby enabling more efficient electron transmission during charging and discharging, reducing energy loss, and helping to improve the battery's energy density and extend its range, meeting the needs of electric vehicles, drones, and other long-range devices.

[0030] 2) Enhanced battery safety: The tight coating formed by the conductive hydrophobic polymer not only isolates the nitrogen-doped black phosphorus from contact with the outside air and moisture, preventing safety hazards caused by oxidation and hydrolysis, and further reducing the impact of moisture on the black phosphorus negative electrode; it also acts as a physical barrier inside the battery, inhibiting the growth of lithium dendrites, reducing the risk of battery short circuits, and significantly improving the safety of the battery during use.

[0031] 3) Broadening the battery's operating temperature range: The introduction of a conductive hydrophobic polymer enhances the material's stability in humid environments. The synergistic effect of nitrogen doping and the coating structure improves the material's structural stability and electrochemical performance in high and low temperature environments. This allows the battery to maintain good charge and discharge performance under extreme temperature conditions, such as cold winters or hot summers, broadening the battery's operating temperature range and expanding its application scenarios.

[0032] 4) Reduced battery production costs: The preparation method of the present invention is simple to operate, operates under mild reaction conditions, and is readily applicable to large-scale industrial production. Compared to some complex and expensive preparation processes, it can effectively reduce production costs and improve production efficiency. This is of great significance for large-scale commercial applications and is expected to promote the popularization of high-performance batteries in the market. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that those skilled in the art may make several adjustments and improvements without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment relates to a method for preparing a black phosphorus composite negative electrode material for a lithium-ion battery; specifically, the method comprises the following steps:

[0036] Preparation of Nitrogen-Doped Black Phosphorus: 1g of black phosphorus powder and 0.5g of melamine were accurately weighed, thoroughly mixed, and placed in a tube furnace. Under argon protection, the temperature was slowly increased at a rate of 5°C / min to 800°C. This temperature was maintained for 3 hours, followed by natural cooling, successfully producing nitrogen-doped black phosphorus.

[0037] 2. Synthesis of conductive hydrophobic polymer: 0.1 mol of 3,4-ethylenedioxythiophene and 0.05 mol of perfluorooctyl ethyl acrylate C 13 H7F 17 O2 was added to a 100 mL three-necked flask, and an appropriate amount of ammonium persulfate was added as an oxidant. The reaction was stirred continuously at a constant stirring speed for 6 hours under ice bath conditions, and a conductive hydrophobic polymer monomer was successfully synthesized.

[0038] 3. In-situ coating: 0.5g of nitrogen-doped black phosphorus was evenly dispersed in a 50mL solution containing 0.1g of a conductive hydrophobic polymer monomer, 0.01g of azobisisobutyronitrile was added as an initiator, and the reaction was stirred continuously for 12h at a constant temperature of 60°C. After the reaction, the conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material was finally obtained through post-processing processes such as centrifugation, washing, and drying. The centrifugation parameters were: speed: 8000rpm, time: 10 minutes, temperature: 25±5°C; anhydrous ethanol: washed twice; vacuum drying at 60°C for 12 hours.

[0039] 4. Slurry preparation: a. Preparation of PVDF solution (50 mg / mL): Weigh an appropriate amount of PVDF with an electronic balance, add NMP solvent in a certain proportion, put it into a magnetic stirrer, and stir at 300r / min for 6 hours until it is completely dissolved. b. Material mixing: Weigh the conductive hydrophobic polymer in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black prepared in step 3 in a mass ratio of 7:2:1, add them to the PVDF solution, and stir evenly with a glass rod. Ball milling dispersion: Transfer the above mixture to a ball mill and ball mill for 1 hour to evenly disperse the in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black in the solution. c. Defoaming treatment: Transfer the ball-milled slurry to a vacuum drying oven and degas at room temperature for 1 hour at -0.08 to -0.1MPa to remove bubbles in the slurry.

[0040] 5. Coating and Drying: Use an automatic coating machine to evenly coat the slurry onto the pretreated copper foil to a coating thickness of 100 μm. After coating, place the copper foil in a vacuum drying oven at 60°C for 12 hours to ensure that the solvent in the slurry is completely evaporated, resulting in a black phosphorus composite anode tightly attached to the copper foil.

[0041] Example 2

[0042] This embodiment relates to a method for preparing a black phosphorus composite negative electrode material for a lithium-ion battery; specifically, the method comprises the following steps:

[0043] Preparation of Nitrogen-Doped Black Phosphorus: 1g of black phosphorus powder and 0.6g of melamine were accurately weighed, thoroughly mixed, and placed in a tube furnace. Under argon protection, the temperature was slowly increased at a rate of 6°C / min to 820°C. This temperature was maintained for 4 hours, followed by natural cooling, successfully producing nitrogen-doped black phosphorus.

[0044] 2. Synthesis of conductive hydrophobic polymer: 0.1 mol of 3,4-ethylenedioxythiophene and 0.05 mol of perfluorooctyl ethyl acrylate C 13 H7F 17 O2 was added to a 100 mL three-necked flask, and an appropriate amount of ammonium persulfate was added as an oxidant. The reaction was stirred continuously at a constant stirring speed for 7 hours under ice bath conditions, and a conductive hydrophobic polymer monomer was successfully synthesized.

[0045] 3. In-situ coating: 0.6g of nitrogen-doped black phosphorus was evenly dispersed in a 50mL solution containing 0.1g of a conductive hydrophobic polymer monomer, 0.01g of azobisisobutyronitrile was added as an initiator, and the reaction was stirred continuously for 10 hours at a constant temperature of 65°C. After the reaction, the conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material was finally obtained through post-processing processes such as centrifugation, washing, and drying. The centrifugation parameters were: speed: 8000rpm, time: 10 minutes, temperature: 25±5°C; anhydrous ethanol: washed twice; vacuum drying at 60°C for 12 hours.

[0046] 4. Slurry preparation: a. Preparation of PVDF solution (50 mg / mL): Weigh an appropriate amount of PVDF with an electronic balance, add NMP solvent in a certain proportion, put it into a magnetic stirrer, and stir at 400r / min for 5 hours until it is completely dissolved. b. Material mixing: Weigh the conductive hydrophobic polymer in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black prepared in step 3 in a mass ratio of 7:2:1, add them to the PVDF solution, and stir evenly with a glass rod. Ball milling dispersion: Transfer the above mixture to a ball mill and ball mill for 1 hour to evenly disperse the in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black in the solution. c. Defoaming treatment: Transfer the ball-milled slurry to a vacuum drying oven and degas at room temperature for 1.5 hours at -0.08 to -0.1MPa to remove bubbles in the slurry.

[0047] 5. Coating and Drying: Use an automatic coating machine to evenly coat the slurry onto the pretreated copper foil to a coating thickness of 100 μm. After coating, place the copper foil in a vacuum drying oven at 60°C for 12 hours to ensure that the solvent in the slurry is completely evaporated, resulting in a black phosphorus composite anode tightly attached to the copper foil.

[0048] Example 3

[0049] This embodiment relates to a method for preparing a black phosphorus composite negative electrode material for a lithium-ion battery; specifically, the method comprises the following steps:

[0050] Preparation of Nitrogen-Doped Black Phosphorus: 1g of black phosphorus powder and 0.5g of melamine were accurately weighed, thoroughly mixed, and placed in a tube furnace. Under argon protection, the temperature was slowly increased at a rate of 7°C / min to 850°C. This temperature was maintained for 5 hours, followed by natural cooling, successfully producing nitrogen-doped black phosphorus.

[0051] 2. Synthesis of conductive hydrophobic polymer: 0.1 mol of 3,4-ethylenedioxythiophene and 0.05 mol of perfluorooctyl ethyl acrylate C 13 H7F 17 O2 was added to a 100 mL three-necked flask, and an appropriate amount of ammonium persulfate was added as an oxidant. The reaction was stirred continuously at a constant stirring speed for 8 hours under ice bath conditions, and a conductive hydrophobic polymer monomer was successfully synthesized.

[0052] 3. In-situ coating: 0.7g of nitrogen-doped black phosphorus was evenly dispersed in a 50mL solution containing 0.1g of a conductive hydrophobic polymer monomer, 0.01g of azobisisobutyronitrile was added as an initiator, and the reaction was stirred continuously at a constant temperature of 70°C for 14h. After the reaction, the conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material was finally obtained through post-processing processes such as centrifugation, washing, and drying. The centrifugation parameters were: speed: 8000rpm, time: 10 minutes, temperature: 25±5°C; anhydrous ethanol: washed twice; vacuum drying at 60°C for 12 hours.

[0053] 4. Slurry preparation: a. Preparation of PVDF solution (50 mg / mL): Weigh an appropriate amount of PVDF with an electronic balance, add NMP solvent in a certain proportion, put it into a magnetic stirrer, and stir at 500r / min for 4 hours until it is completely dissolved. b. Material mixing: Weigh the conductive hydrophobic polymer in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black prepared in step 3 in a mass ratio of 7:2:1, add them to the PVDF solution, and stir evenly with a glass rod. Ball milling dispersion: Transfer the above mixture to a ball mill and ball mill for 1 hour to evenly disperse the in situ coated nitrogen-doped black phosphorus negative electrode material and conductive carbon black in the solution. c. Defoaming treatment: Transfer the ball-milled slurry to a vacuum drying oven and degas at room temperature for 2 hours at -0.08 to -0.1MPa to remove bubbles in the slurry.

[0054] 5. Coating and Drying: Use an automatic coating machine to evenly coat the slurry onto the pretreated copper foil to a coating thickness of 100 μm. After coating, place the copper foil in a vacuum drying oven at 60°C for 12 hours to ensure that the solvent in the slurry is completely evaporated, resulting in a black phosphorus composite anode tightly attached to the copper foil.

[0055] Comparative Example 1

[0056] The only difference between this comparative example and Example 1 is that undoped black phosphorus is used instead of nitrogen-doped black phosphorus. The specific steps include:

[0057] 1. In-situ coating: 0.5g of black phosphorus powder was evenly dispersed in 50mL of a solution containing 0.1g of a conductive hydrophobic polymer monomer. 0.01g of azobisisobutyronitrile was added as an initiator. The reaction was stirred continuously at a constant temperature of 60°C for 12 hours. After the reaction, the conductive hydrophobic polymer in-situ coated black phosphorus anode material was obtained through post-processing processes such as centrifugation, washing, and drying.

[0058] 2. Slurry preparation: a. Preparation of PVDF solution (50 mg / mL): Weigh an appropriate amount of PVDF with an electronic balance, add NMP solvent in a certain proportion, put it into a magnetic stirrer, and stir at 300r / min for 6 hours until it is completely dissolved. b. Material mixing: Weigh the conductive hydrophobic polymer in situ coated black phosphorus negative electrode material and conductive carbon black prepared in step 1 in a mass ratio of 7:2:1, add them to the PVDF solution, and stir evenly with a glass rod. Ball milling dispersion: Transfer the above mixture to a ball mill and ball mill for 1 hour to evenly disperse the in situ coated black phosphorus negative electrode material and conductive carbon black in the solution. c. Defoaming treatment: Transfer the ball-milled slurry to a vacuum drying oven and degas at -0.08 to -0.1MPa for 1-2 hours to remove bubbles in the slurry.

[0059] 3. Coating and Drying: Using an automatic coating machine, the slurry is evenly coated onto the pretreated copper foil to a coating thickness of 100 μm. After coating, the copper foil is placed in a vacuum drying oven at 60°C for 12 hours to ensure that the solvent in the slurry is completely evaporated, resulting in a black phosphorus composite anode tightly attached to the copper foil.

[0060] Charge and discharge cycle performance test:

[0061] The black phosphorus composite negative electrode, lithium sheet and separator obtained in Examples 1-3 and Comparative Example 1 were assembled and injected into a half-cell. The electrolyte was 1 mol / L LiPF6, EC / DMC=1:1 (volume ratio).

[0062] Test method: A constant current charge and discharge test system was used to perform charge and discharge cycle tests on the half-cells obtained in Examples 1-3 and Comparative Example 1.

[0063] Test conditions: Set the current density to 0.1C and the charge and discharge voltage range to 0.01V-2.5V; cycle 50 times at this current density.

[0064] Test data: record the charge and discharge specific capacity of each cycle. As shown in Table 1:

[0065] Table 1

[0066] Group Initial discharge capacity (mAh / g) Discharge capacity after 50 cycles (mAh / g) Example 1 1432 1300 Example 2 1420 1285 Example 3 1430 1300 Comparative Example 1 1280 1075

[0067] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a black phosphorus composite negative electrode material; characterized in that: The method comprises the following steps: S1. In the presence of an oxidant and in an ice bath, 3,4-ethylenedioxythiophene and perfluorooctylethyl acrylate react to synthesize a conductive hydrophobic polymer monomer; S2. Dispersing nitrogen-doped black phosphorus in the conductive hydrophobic polymer monomer solution obtained in S1, adding an initiator to initiate an in-situ polymerization reaction; after the reaction, centrifuging, washing, and drying to obtain a conductive hydrophobic polymer in-situ coated nitrogen-doped black phosphorus negative electrode material, i.e., the black phosphorus composite negative electrode material.

2. The method for preparing the black phosphorus composite negative electrode material according to claim 1; characterized in that: In S1, the oxidant is at least one of ammonium persulfate, ferric chloride, and hydrogen peroxide.

3. The method for preparing the black phosphorus composite negative electrode material according to claim 1; characterized in that: In S1, the molar ratio of 3,4-ethylenedioxythiophene to perfluorooctylethyl acrylate is (1.5-2.5):1; and / or, The ice bath reaction time is 5 to 8 hours.

4. The method for preparing the black phosphorus composite negative electrode material according to claim 1; characterized in that: The preparation of the nitrogen-doped black phosphorus includes: mixing black phosphorus powder with a nitrogen-containing compound, calcining at high temperature in an inert gas protection environment, and then naturally cooling to obtain the nitrogen-doped black phosphorus.

5. The method for preparing the black phosphorus composite negative electrode material according to claim 4; characterized in that, The nitrogen-containing compound is selected from at least one of melamine and ammonium carbonate; and / or, The black phosphorus powder and the nitrogen-containing compound are mixed at a P:N molar ratio of 1:0.6 to 1:

1.

6. The method for preparing the black phosphorus composite negative electrode material according to claim 4; characterized in that: The high temperature calcination is carried out by heating the temperature to 800-850° C. at a heating rate of 5-7° C. / min and keeping the temperature for 3-5 hours.

7. The method for preparing the black phosphorus composite negative electrode material according to claim 1; characterized in that: In S2, the mass ratio of nitrogen-doped black phosphorus to the conductive hydrophobic polymer monomer solution is 4 to 8:

1.

8. The method for preparing the black phosphorus composite negative electrode material according to claim 1, characterized in that: In S2, the initiator comprises azobisisobutyronitrile; and / or, The mass ratio of the initiator to the conductive hydrophobic polymer monomer solution is 1:10-12; and / or, The temperature of the in-situ polymerization reaction is 50-70° C., and the reaction time is 10-14 hours.

9. A black phosphorus composite negative electrode material prepared by the method according to any one of claims 1 to 8.

10. Use of the black phosphorus composite negative electrode material according to claim 9 in battery preparation.