A black phosphorus composite material with high-rate lithium storage performance and its preparation method and application

Abstract

The present invention discloses a black phosphorus composite material with high-rate lithium storage performance, and its preparation method and application. The preparation method of the black phosphorus composite material with high-rate lithium storage performance comprises the following steps: in an inert gas atmosphere, red phosphorus is mixed with a nitrogen-containing compound, and then ball milling is carried out, the ball milling product is washed to remove excess organic matter, and nitrogen-doped black phosphorus is prepared after vacuum drying; the nitrogen-containing compound is at least one of urea, thiourea, melamine, amino acid, ammonium chloride and ammonium sulfate; in an inert gas atmosphere, the nitrogen-doped black phosphorus in step (1) is mixed with a carbon material, and then ball milling is carried out to prepare the black phosphorus composite material. The black phosphorus composite material prepared by the present invention is used as a negative electrode material for lithium-ion batteries, which enables lithium ions to quickly enter the black phosphorus interlayer, and has excellent rate performance while being simple in process, environmentally friendly, and easy to scale.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage materials, and in particular relates to a black phosphorus composite material with high-rate lithium storage performance, a preparation method thereof, and applications thereof. Background Art

[0002] The wrinkled layered black phosphorus (BP) material has a high theoretical specific capacity of 2596 mAh / g (about 7 times that of commercial graphite, only lower than Si 4200 mAh / g and Li metal 3860 mAh / g), as well as a suitable charge and discharge potential (~0.7 V vs. Li + / Li), becoming the best candidate for fast-charging negative electrode materials. + The diffusion barrier along the zigzag (ZZ) direction of black phosphorus is only 0.08 eV, much lower than that of silicon (0.58 eV). However, the formation of the Li3P phase during the lithium insertion process in BP produces a large volume expansion (~300%), which causes the pulverization of the electrode material and the continuous formation and fragmentation of the solid-electrolyte interphase (SEI) on the electrode surface. This results in poor actual electrochemical lithium storage performance of BP, inability to fully release its theoretical capacity, and low capacity at high current density. Currently, researchers have combined black phosphorus with carbon-based materials to effectively improve reversibility and capacity decay during cycling, but still face the bottleneck of poor rate performance. Recent studies have shown that the edges of the BP nanoparticle structure prepared by the exfoliation of black phosphorus bulk into few-layer BP nanosheets or ball milling have defects or hanging atoms, which induces the reconstruction of the edge atomic structure. As a result, the diffusion barrier of lithium ions into the black phosphorus interlayer along the ZZ direction is increased to 0.52 eV, seriously hindering the rapid entry of lithium ions into the black phosphorus interlayer, resulting in poor rate performance. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of the present invention is to overcome the defects of the existing technology and provide a black phosphorus composite material with high-rate lithium storage performance and its preparation method and application.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for preparing a black phosphorus composite material with high-rate lithium storage performance comprises the following steps:

[0006] (1) preparing nitrogen-doped black phosphorus: mixing red phosphorus with a nitrogen-containing compound under an inert gas atmosphere, then subjecting the mixture to a ball milling reaction, washing the milled product to remove excess organic matter, and vacuum drying the product to obtain nitrogen-doped black phosphorus; the nitrogen-containing compound is at least one of urea, thiourea, melamine, amino acid, ammonium chloride, and ammonium sulfate;

[0007] (2) Preparing a black phosphorus composite material: Under an inert gas atmosphere, the nitrogen-doped black phosphorus prepared in step (1) is mixed with a carbon material, and then ball-milled to obtain the black phosphorus composite material.

[0008] Preferably, in step (1), the mass ratio of red phosphorus to nitrogen-containing compound is 10:1-5.

[0009] Preferably, in step (1), the ball-to-material ratio (mass ratio of ball milling beads to mixture) of the ball milling reaction is (20-100):1.

[0010] Preferably, in step (1), the ball milling reaction adopts a high-energy swing array ball mill, the ball milling speed is 800-1200 rpm / min, and the ball milling time is 1-10 hours; the ball milling mode is intermittent operation, unidirectional operation for 10-30 minutes, and stop operation for 10-30 minutes.

[0011] Preferably, in step (1), the washing method is: first washing with water and then washing with ethanol.

[0012] Preferably, in step (2), the mass ratio of nitrogen-doped black phosphorus to carbon material is 1 to 5:1.

[0013] Preferably, in step (2), the carbon material is at least one of expanded graphite, graphite, carbon black, Super P and biomass carbon.

[0014] Preferably, in step (2), the ball-to-material ratio of ball milling is (10-100):1.

[0015] Preferably, in step (2), the ball mill adopts a high-energy swing array ball mill, the ball mill speed is 800-1200 rpm / min, the ball milling time is 2-10 hours, and the ball milling mode is intermittent operation, unidirectional operation for 10-30 minutes, and stop operation for 10-30 minutes.

[0016] Preferably, the inert gas in steps (1) and (2) is argon.

[0017] Preferably, the ball milling in steps (1) and (2) uses stainless steel ball milling beads.

[0018] The black phosphorus composite material with high-rate lithium storage performance prepared by the above-mentioned preparation method of the black phosphorus composite material with high-rate lithium storage performance.

[0019] The application of the above-mentioned black phosphorus composite material with high-rate lithium storage performance in the preparation of lithium-ion battery negative electrode materials.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This method introduces nitrogen in situ during the ball-milling process of converting red phosphorus to black phosphorus, achieving doping modification. Nitrogen atoms are then used to dope the black phosphorus edges, regulating the atomic and electronic structures of the black phosphorus edges. This allows for rapid lithium ion entry into the black phosphorus interlayers, resulting in excellent rate performance. Furthermore, the preparation process is simple, environmentally friendly, and easily scalable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XPS photoelectron energy spectrum of nitrogen-doped black phosphorus prepared in step (1) of Example 1, where the high-resolution energy spectra of P and N correspond from left to right respectively.

[0023] Figure 2 This is a comparison chart of the charge and discharge performance of lithium-ion batteries assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 1 and the black phosphorus composite negative electrode material prepared in Comparative Example 1 at different current densities.

[0024] Figure 3 This is a graph of the charge and discharge performance of a lithium-ion battery assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 2 at different current densities.

[0025] Figure 4 This is a graph of the charge and discharge performance of a lithium-ion battery assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 3 at different current densities. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] Example 1

[0028] A method for preparing a black phosphorus composite material with high-rate lithium storage performance comprises the following steps:

[0029] (1) In a 0.1 MPa argon atmosphere glove box, 1 g of red phosphorus particles and 0.3 g of urea were added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 2 h. The specific operation mode was a single-direction operation time of 30 min, a stop operation time of 30 min, and a number of operations of 4 times. The ball milling speed was 1200 rpm / min. After the ball milling was completed, the ball milled product was washed with water and ethanol three times each to remove excess urea, and then dried in a vacuum oven at 60°C to obtain nitrogen-doped black phosphorus powder.

[0030] (2) In a 0.1 MPa argon atmosphere glove box, 0.7 g of nitrogen-doped black phosphorus and 0.3 g of expanded graphite were mixed and then added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 5 hours. The specific operation mode was a one-way operation time of 30 minutes, a stop operation time of 30 minutes, a number of operations of 10 times, and a ball milling speed of 1200 rpm / min. After the ball milling was completed, the material was removed from the ball mill in the argon glove box to obtain the black phosphorus composite material with high-rate lithium storage performance.

[0031] The black phosphorus composite material with high-rate lithium storage performance prepared in Example 1 is used as a negative electrode material for lithium-ion batteries.

[0032] The lithium-ion battery was prepared by mixing the high-rate lithium storage black phosphorus composite material prepared in Example 1, a conductive agent (Super-P), and a binder (sodium carboxymethyl cellulose) in a mass ratio of 70:15:15 in water. The mixture was then coated onto copper foil to form an electrode sheet, which was then vacuum-dried. In an argon-filled glove box, metallic lithium was used as the counter electrode, and 1M LiPF6 was dissolved in a mixture of EC+DEC+EMC (1:1:1 v%) and 10% FEC as the electrolyte. The cells were assembled into 2025 button-shaped cells for testing. The test conditions were: charge and discharge current density of 0.5-10 A / g, and charge and discharge cutoff voltage of 0.01-2.0 V.

[0033] Figure 1 This is the XPS photoelectron energy spectrum of nitrogen-doped black phosphorus prepared in step (1) of Example 1. The existence of PN covalent bonds can be clearly observed through the high-resolution energy spectrum of P and N, indicating that the present invention successfully achieves N doping on the black phosphorus surface.

[0034] Figure 2 This is a comparison chart of the charge and discharge performance of lithium-ion batteries assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 1 and the black phosphorus composite negative electrode material prepared in Comparative Example 1 at different current densities. Figure 2 It can be observed that the black phosphorus composite material with high-rate lithium storage performance prepared by the present invention, that is, the nitrogen-doped black phosphorus composite negative electrode material (NBP-C), has a reversible capacity of up to 1019.65 mAh / g at a current density of 10 A / g, and a capacity retention rate of 68% (compared to the capacity at a current density of 0.5 A / g); while the black phosphorus composite negative electrode material (BP-C) prepared in Comparative Example 1 has a reversible capacity of only 691.9 mAh / g at a current density of 10 A / g, and a capacity retention rate of only 40% (compared to the capacity at a current density of 0.5 A / g), which is significantly lower than the electrochemical performance of the nitrogen-doped black phosphorus composite material prepared in Example 1.

[0035] Example 2

[0036] A method for preparing a black phosphorus composite material with high-rate lithium storage performance comprises the following steps:

[0037] (1) In a 0.1 MPa argon atmosphere glove box, 1 g of red phosphorus particles and 0.3 g of urea were added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 2 h. The specific operation mode was a single-direction operation time of 30 min, a stop operation time of 30 min, and a number of operations of 4 times. The ball milling speed was 1200 rpm / min. After the ball milling was completed, the ball milled product was washed with water and ethanol three times each to remove excess urea, and then dried in a vacuum oven at 60°C to obtain nitrogen-doped black phosphorus powder.

[0038] (2) In a 0.1 MPa argon atmosphere glove box, 0.6 g of nitrogen-doped black phosphorus and 0.4 g of expanded graphite were mixed and then added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 5 hours. The specific operation mode was a single-direction operation time of 30 minutes, a stop operation time of 30 minutes, a number of operations of 10 times, and a ball milling speed of 1200 rpm / min. After the ball milling was completed, the material was removed from the ball mill in the argon glove box to obtain a black phosphorus composite material with high-rate lithium storage performance.

[0039] The black phosphorus composite material with high-rate lithium storage performance prepared in Example 2 is used as the negative electrode of a lithium-ion battery. The preparation and testing methods of the lithium-ion battery are the same as those in Example 1. Figure 3 The figure shows the charge and discharge performance of the lithium-ion battery assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 2 at different current densities. Figure 3 It can be observed that the reversible capacity of the nitrogen-doped black phosphorus composite negative electrode material is as high as 1120.3 mAh / g at a current density of 10 A / g, which is significantly higher than the electrochemical performance of the black phosphorus composite material prepared in Comparative Example 1.

[0040] Example 3

[0041] A method for preparing a black phosphorus composite material with high-rate lithium storage performance comprises the following steps:

[0042] (1) In a 0.1 MPa argon atmosphere glove box, 1 g of red phosphorus particles and 0.1 g of urea were added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 2 h. The specific operation mode was a one-way operation time of 30 min, a stop operation time of 30 min, and a number of runs. The ball milling speed was 1200 rpm / min. After the ball milling was completed, the ball milled product was washed with water and ethanol three times each to remove excess urea, and then dried in a vacuum oven at 60°C to obtain nitrogen-doped black phosphorus powder.

[0043] (2) In a 0.1 MPa argon atmosphere glove box, 0.7 g of nitrogen-doped black phosphorus and 0.3 g of expanded graphite were mixed and then added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 5 hours. The specific operation mode was a single-direction operation time of 30 minutes, a stop operation time of 30 minutes, a number of operations of 10 times, and a ball milling speed of 1200 rpm / min. After the ball milling was completed, the material was removed from the ball mill in the argon glove box to obtain a black phosphorus composite material with high-rate lithium storage performance.

[0044] The black phosphorus composite material with high-rate lithium storage performance prepared in Example 3 is used as the negative electrode of a lithium-ion battery. The preparation and testing methods of the lithium-ion battery are the same as those in Example 1. Figure 4 The figure shows the charge and discharge performance of the lithium-ion battery assembled with the black phosphorus composite material with high-rate lithium storage performance prepared in Example 3 at different current densities. Figure 4 It can be observed that the reversible capacity of the nitrogen-doped black phosphorus composite negative electrode material is as high as 833.3 mAh / g at a current density of 10 A / g, which is also higher than the electrochemical performance of the black phosphorus composite material prepared in Comparative Example 1 (691.9 mAh / g), but lower than that of Examples 1 and 2, indicating that nitrogen doping can improve the rate performance of black phosphorus, but the doping amount also affects the rate performance of black phosphorus.

[0045] Comparative Example 1

[0046] A method for preparing a black phosphorus composite material, comprising the following steps:

[0047] (1) In a 0.1 MPa argon atmosphere glove box, 1 g of red phosphorus particles was added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 2 h. The specific operation mode was a one-way operation time of 30 min, a stop operation time of 30 min, and a number of runs of 4 times. The ball milling speed was 1200 rpm / min. After the ball milling was completed, the material was removed from the ball mill in the argon glove box to obtain black phosphorus powder.

[0048] (2) In a 0.1 MPa argon atmosphere glove box, 0.7 g of black phosphorus and 0.3 g of expanded graphite were mixed and then added to a ball mill with a ball-to-material ratio of 50:1. High-energy swing ball milling was performed for 5 h. The specific operation mode was a single-direction operation time of 30 min, a stop operation time of 30 min, and a number of runs of 10 times. The ball milling speed was 1200 rpm / min. After the ball milling was completed, the material was removed from the ball mill in the argon glove box to obtain a black phosphorus composite negative electrode material.

[0049] The black phosphorus composite material prepared in Comparative Example 1 was used as a negative electrode of a lithium ion battery. The preparation and testing methods of the lithium ion battery were the same as those in Example 1. Figure 2The figure shows the charge and discharge performance of a lithium-ion battery assembled with the black phosphorus composite material prepared in Comparative Example 1 and the nitrogen-doped black phosphorus composite negative electrode material prepared in Example 1 at different current densities. It can be observed that the black phosphorus composite material (BP-C) in Comparative Example 1 has a reversible capacity of only 691.9 mAh / g at a current density of 10 A / g, and a capacity retention rate of only 40% (compared to the capacity at a current density of 0.5 A / g), which is significantly lower than the electrochemical performance of the nitrogen-doped black phosphorus composite materials prepared in Examples 1 to 3.

[0050] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a black phosphorus composite material with high-rate lithium storage performance, characterized in that: The steps include: (1) Preparation of nitrogen-doped black phosphorus: red phosphorus and a nitrogen-containing compound are mixed under an inert gas atmosphere, followed by ball milling, the ball milled product is washed to remove excess organic matter, and vacuum dried to obtain nitrogen-doped black phosphorus; the nitrogen-containing compound is urea; the nitrogen-doped black phosphorus utilizes nitrogen atoms to dope the edges of black phosphorus; (2) Preparing a black phosphorus composite material: mixing the nitrogen-doped black phosphorus prepared in step (1) with a carbon material under an inert gas atmosphere, and then ball milling the mixture to obtain the black phosphorus composite material; The mass ratio of the red phosphorus to the nitrogen-containing compound in step (1) is 10:1-5; The ball-to-material ratio of the ball milling reaction in step (1) is (20-100):1; The ball milling reaction in step (1) adopts a high-energy swing array ball mill, the ball milling speed is 800~1200 rpm / min, and the ball milling time is 1~10 h; the ball milling mode is intermittent operation, unidirectional operation for 10~30 min, and stop operation for 10~30 min.

2. The method for preparing a black phosphorus composite material with high-rate lithium storage performance according to claim 1, characterized in that: The mass ratio of the nitrogen-doped black phosphorus to the carbon material in step (2) is 1-5:

1.

3. The method for preparing a black phosphorus composite material with high-rate lithium storage performance according to claim 1, characterized in that: The ball-to-material ratio of the ball milling in step (2) is (10-100):

1.

4. The method for preparing a black phosphorus composite material with high-rate lithium storage performance according to any one of claims 1 to 3, characterized in that: The ball milling in step (2) adopts a high-energy swing array ball milling, the ball milling speed is 800~1200 rpm / min, the ball milling time is 2~10 h, and the ball milling mode is intermittent operation, unidirectional operation for 10~30 min, and stop operation for 10~30 min.

5. The method for preparing a black phosphorus composite material with high-rate lithium storage performance according to claim 1, characterized in that: The carbon material in step (2) is at least one of expanded graphite, carbon black and biomass carbon.

6. The method for preparing a black phosphorus composite material with high-rate lithium storage performance according to claim 5, characterized in that: The washing method in step (1) is: first washing with water and then washing with ethanol; The inert gas in steps (1) and (2) is argon; The ball milling in steps (1) and (2) uses stainless steel ball milling beads.

7. A black phosphorus composite material with high-rate lithium storage performance prepared by the method for preparing a black phosphorus composite material with high-rate lithium storage performance according to any one of claims 1 to 6.

8. Use of the black phosphorus composite material with high-rate lithium storage performance as claimed in claim 7 in the preparation of negative electrode materials for lithium-ion batteries.

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