Lithium ion battery negative electrode material and preparation method thereof

Abstract

The application discloses a lithium ion battery negative electrode material and a preparation method thereof. The lithium ion battery negative electrode material comprises microscale flower-shaped molybdenum telluride self-assembled by two-dimensional nanosheets. The preparation method of the microscale flower-shaped molybdenum telluride comprises the following steps: respectively adding a tellurium source and a molybdenum source into deionized water to prepare solutions, and then adding 2-amino-3-(4-hydroxyphenyl) propionic acid to obtain a mixed solution; the mixed solution is placed into a microwave reactor to react, and the product is collected and then washed, dried and calcined under a protective atmosphere to be prepared; the preparation method of the lithium ion battery negative electrode material comprises the following steps: mixing and grinding the microscale flower-shaped molybdenum telluride, acetylene black and polyvinylidene fluoride, adding N-methyl pyrrolidone and continuing to grind, coating the obtained slurry on a copper foil, and vacuum drying to obtain the lithium ion battery negative electrode material. The lithium ion battery negative electrode material has the advantages of stable structure, high specific capacity and good cycle performance, and the energy density and cycle life of the lithium ion battery are improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology and relates to a lithium-ion battery anode material and its preparation method. Background Technology

[0002] To meet the ever-increasing energy demand while avoiding global resource depletion and long-term environmental damage, finding energy storage batteries with high operating voltage, high energy density, long cycle life, low self-discharge, and environmental friendliness has become an urgent problem to solve. Lithium-ion batteries, as a widely used and highly efficient energy storage battery, have been highly anticipated. In recent years, lithium-ion batteries have demonstrated significant application prospects in portable electronic devices, electric vehicles, aerospace, and other fields. However, with increasingly higher performance requirements for energy storage batteries, developing lithium-ion batteries with higher energy density, higher specific capacity, and better cycle stability is an inevitable trend in the future development of energy storage batteries.

[0003] The key to developing high-performance lithium-ion batteries lies in finding suitable electrode materials. Currently, crystalline materials widely studied and used in lithium-ion battery anodes often suffer from structural damage and pulverization during charging and discharging at high current densities, resulting in poor cycle stability and severely limiting the lifespan of lithium-ion batteries.

[0004] In recent years, two-dimensional layered transition metal dichalcogenide (TMDC) nanocrystals have been increasingly developed and used as battery materials. These nanocrystals consist of numerous stacked layers, each composed of many robust XMX structures. The layers are connected by weak van der Waals forces, forming a layered structure. Due to the large interlayer spacing and weak interlayer forces, lithium ions can easily undergo reversible electrochemical insertion and extraction, thereby increasing the material's lithium storage capacity and rate performance. Molybdenum ditelluride is a unique half-metal in TMDCs, with its 1T' phase exhibiting high magnetoresistivity (MR), high carrier mobility, and a narrow bandgap. These excellent properties make it highly promising for applications in optical components and field-effect transistors, and it shows great potential for lithium storage. However, molybdenum ditelluride is prone to agglomeration, and it preferentially grows inert inner layer structures rather than active sheet edges. The large number of agglomerates further inhibits the exposure of active edges, which is not conducive to the extension of cycle life. In addition, due to its poor conductivity, the excellent performance of molybdenum ditelluride is usually not fully utilized.

[0005] Therefore, it is very important to modify the structure of molybdenum distellide to make it applicable to lithium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a lithium-ion battery anode material and its preparation method. The technical solution adopted by this invention is as follows:

[0007] In a first aspect, the present invention provides a lithium-ion battery anode material comprising micron-sized flower-shaped molybdenum telluride self-assembled from two-dimensional nanosheets.

[0008] The method for preparing the micron-sized flower-shaped molybdenum telluride includes:

[0009] Step 1: Add the tellurium source and molybdenum source to deionized water to prepare solution A with a tellurium ion concentration of 0.01-0.03 mol / L and solution B with a molybdenum ion concentration of 0.005-0.015 mol / L;

[0010] Step 2: Add solution B dropwise to solution A, and add 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture, wherein the volume ratio of solution B to solution A is 1:(1-3), and the concentration of 2-amino-3-(4-hydroxyphenyl)propionic acid in the mixture is 0.01-0.03 mol / L;

[0011] Step 3: Place the mixture into a microwave reactor for reaction and collect the resulting solid crude product;

[0012] Step 4: The solid crude product is washed, dried, and calcined under a protective atmosphere to obtain the micron-sized flower-shaped molybdenum telluride.

[0013] In one embodiment of the present invention, the thickness of the two-dimensional nanosheet is 1 to 5 nm.

[0014] In one embodiment of the present invention, in step one, the tellurium source includes sodium tellurate and telluric acid, and the molybdenum source includes molybdic acid and sodium molybdate.

[0015] In one embodiment of the present invention, in step three, the time of the microwave reactor is set to 10 to 15 minutes, and the power of the microwave reactor is set to 300 to 400W.

[0016] In one embodiment of the present invention, in step four, the washing solvent is deionized water, and the washing is performed 3 to 4 times with the deionized water.

[0017] In one embodiment of the present invention, in step four, the drying temperature is 50-70°C and the drying time is 6-9 hours.

[0018] In one embodiment of the present invention, the calcination temperature is 450-490°C and the calcination time is 2-3 hours.

[0019] In one embodiment of the present invention, the protective atmosphere is argon or nitrogen.

[0020] Secondly, the present invention also provides a method for preparing a lithium-ion battery anode material. This method involves using the aforementioned micron-sized flower-shaped molybdenum telluride as the active material for the lithium-ion battery. The micron-sized flower-shaped molybdenum telluride is mixed with acetylene black and polyvinylidene fluoride at a mass ratio of 9:0.5:0.5. After grinding for 10-20 minutes, 20-30 microliters of N-methylpyrrolidone are added, and grinding continues for another 10-20 minutes. The resulting slurry is then coated onto a copper foil and vacuum dried at 100°C for 8-10 hours to obtain the lithium-ion battery anode material.

[0021] The beneficial effects of this invention are:

[0022] The lithium-ion battery anode material of this invention comprises micron-sized flower-shaped molybdenum telluride, which is self-assembled from two-dimensional nanosheets. As an active material in lithium-ion batteries, the molybdenum telluride, being micron-sized overall, is less prone to agglomeration during its synthesis and the preparation of the lithium-ion battery anode material. The microstructure of molybdenum telluride consists of ultrathin two-dimensional nanosheets, exposing more active sites for lithium-ion reaction, shortening the lithium-ion migration distance, and increasing the lithium-ion reaction rate. In the micron-sized flower-shaped molybdenum telluride, the two-dimensional nanosheets interconnect to form a three-dimensional structure, further reducing stress damage during the lithium-ion reaction process and improving the structural stability of the lithium-ion battery anode material. The micron-sized flower-shaped molybdenum telluride, as an active material in lithium-ion battery anode materials, exhibits high specific capacity and good cycle performance, thereby improving the energy density and cycle life of lithium-ion batteries. Attached Figure Description

[0023] Figure 1 The XRD pattern of micron-sized flower-shaped molybdenum telluride provided in Embodiment 1 of the present invention;

[0024] Figure 2 This is a scanning electron microscope image of micron-sized flower-shaped molybdenum telluride provided in Embodiment 1 of the present invention;

[0025] Figure 3 This is a transmission electron microscope (TEM) image of micron-sized flower-shaped molybdenum telluride provided in Embodiment 1 of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but the embodiments of the present invention are not limited thereto.

[0027] This invention provides a lithium-ion battery anode material comprising micron-sized flower-like molybdenum telluride self-assembled from two-dimensional nanosheets. The thickness of the two-dimensional nanosheets is 1–5 nm.

[0028] Micron-sized flower-shaped molybdenum telluride, as an active material for lithium-ion batteries, is micron-sized overall, making it less prone to agglomeration during the synthesis of molybdenum telluride and the preparation of lithium-ion battery anode materials. The microstructure of molybdenum telluride consists of ultrathin two-dimensional nanosheets, exposing more active sites for lithium-ion reaction, shortening the lithium-ion migration distance, and increasing the lithium-ion reaction rate. In micron-sized flower-shaped molybdenum telluride, the two-dimensional nanosheets are interconnected to form a three-dimensional structure, further reducing stress damage during its reaction with lithium-ions and improving the structural stability of lithium-ion battery anode materials.

[0029] The method for preparing micron-sized flower-like molybdenum telluride of the present invention includes:

[0030] Step 1: Add the tellurium source and molybdenum source to deionized water to prepare solution A with a tellurium ion concentration of 0.01–0.03 mol / L and solution B with a molybdenum ion concentration of 0.005–0.015 mol / L. The tellurium source includes sodium tellurate and telluric acid, and the molybdenum source includes molybdic acid and sodium molybdate.

[0031] Step 2: Add solution B dropwise to solution A, and add 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture. The volume ratio of solution B to solution A is 1:(1-3), and the concentration of 2-amino-3-(4-hydroxyphenyl)propionic acid in the mixture is 0.01-0.03 mol / L.

[0032] Step 3: Place the mixture into a microwave reactor for reaction and collect the resulting solid crude product. Preferably, the microwave reactor time is set to 10-15 minutes, and the microwave reactor power is set to 300-400W.

[0033] Step 4: The crude solid product is washed, dried, and calcined under a protective atmosphere to obtain micron-sized flower-like molybdenum telluride. Preferably, the washing solvent is deionized water, and the product is washed 3-4 times with deionized water. The drying temperature is 50-70℃, and the drying time is 6-9 hours. The calcination temperature is 450-490℃, and the calcination time is 2-3 hours. Argon or nitrogen is selected as the protective atmosphere in this invention.

[0034] The micron-sized flower-like molybdenum telluride provided by this invention has a simple preparation method, short reaction time, low calcination temperature, is environmentally friendly, uses readily available and common equipment, and has low energy consumption, which is beneficial for practical industrial applications. Compared with the energy-intensive solid-state high-temperature sintering method used in common molybdenum telluride preparation processes, the preparation method of this invention has significant advantages. In addition, the micron-sized molybdenum telluride prepared by this invention has a unique morphology, high purity, and good crystallinity. The self-assembly of molybdenum telluride nanosheets into micron-sized flower-like molybdenum telluride, as a negative electrode material for lithium-ion batteries, improves the lithium-ion reaction rate and structural stability.

[0035] This invention also provides a method for preparing a lithium-ion battery anode material. The method uses the micron-sized flower-shaped molybdenum telluride of this invention as the active material for the lithium-ion battery. The micron-sized flower-shaped molybdenum telluride is mixed with acetylene black and polyvinylidene fluoride at a mass ratio of 9:0.5:0.5. After grinding for 10-20 minutes, 20-30 μL of N-methylpyrrolidone is added, and grinding continues for another 10-20 minutes. The resulting slurry is coated onto a copper foil and vacuum dried at 100°C for 8-10 hours to obtain the lithium-ion battery anode material.

[0036] The method for preparing lithium-ion battery anode materials proposed in this invention does not require large-scale equipment or harsh reaction conditions. The raw materials are inexpensive and readily available, resulting in low cost. No post-processing is required, making it environmentally friendly, highly safe, and suitable for large-scale production.

[0037] The following detailed embodiments provide a comparative explanation of the micron-scale flower-shaped molybdenum telluride preparation method provided by the present invention, and the performance of the prepared materials is tested to verify the beneficial effects of the present invention.

[0038] Example 1:

[0039] The method for preparing micron-sized flower-like molybdenum telluride in this embodiment includes:

[0040] Sodium tellurate was added to deionized water to prepare solution A with a tellurium ion concentration of 0.03 mol / L; molybdic acid was added to deionized water to prepare solution B with a molybdenum ion concentration of 0.015 mol / L. Solution B was then added dropwise to solution A at a volume ratio of 1:3, followed by the addition of 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture with a 2-amino-3-(4-hydroxyphenyl)propionic acid concentration of 0.03 mol / L. The mixture was placed in a microwave reactor and reacted at 400 W for 10 minutes. After the reaction, the resulting crude solid product was collected. The crude solid product was washed four times with deionized water and then dried at 70°C for 6 hours. Finally, it was calcined at 490°C for 2 hours under an argon atmosphere to obtain micron-sized flower-like molybdenum telluride.

[0041] See Figure 1 , Figure 1 The XRD pattern of the product prepared for this embodiment is from... Figure 1 It can be determined that the main component of the product is molybdenum ditelluride, and the product has high purity and good crystallinity.

[0042] See Figure 2 , Figure 2 The scanning electron microscope image of the product prepared in this embodiment is from... Figure 2 It can be seen that the product has distinct morphological characteristics, consisting of thin nanosheets assembled into a micron-sized flower-like morphology, according to the attached... Figure 2Based on the length of the scale, the diameter of the product is calculated to be approximately 2μm.

[0043] See Figure 3 , Figure 3 The transmission electron microscope (TEM) image of the product prepared in this embodiment is shown below. Figure 3 This further confirms that the prepared product is a unique micron-scale flower-like structure formed by the self-assembly of two-dimensional nanosheets.

[0044] Example 2:

[0045] The method for preparing micron-sized flower-like molybdenum telluride in this embodiment includes:

[0046] Telluric acid was added to deionized water to prepare solution A with a tellurium ion concentration of 0.01 mol / L; sodium molybdate was added to deionized water to prepare solution B with a molybdenum ion concentration of 0.005 mol / L. Solution B was then added dropwise to solution A at a volume ratio of 1:1, followed by the addition of 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture with a 2-amino-3-(4-hydroxyphenyl)propionic acid concentration of 0.01 mol / L. The mixture was placed in a microwave reactor and reacted at 300 W for 15 minutes. After the reaction, the resulting crude solid product was collected. The crude solid product was washed three times with deionized water and then dried at 50°C for 9 hours. Finally, it was calcined at 450°C for 3 hours under an argon atmosphere to obtain micron-sized flower-like molybdenum telluride.

[0047] Example 3:

[0048] The method for preparing micron-sized flower-like molybdenum telluride in this embodiment includes:

[0049] Sodium tellurate was added to deionized water to prepare solution A with a tellurium ion concentration of 0.02 mol / L; molybdic acid was added to deionized water to prepare solution B with a molybdenum ion concentration of 0.01 mol / L. Solution B was then added dropwise to solution A at a volume ratio of 1:2, followed by the addition of 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture with a 2-amino-3-(4-hydroxyphenyl)propionic acid concentration of 0.02 mol / L. The mixture was placed in a microwave reactor and reacted at 350 W for 10 minutes. After the reaction, the resulting crude solid product was collected. The crude solid product was washed three times with deionized water and then dried at 60 °C for 8 hours. Finally, it was calcined at 460 °C for 3 hours under an argon atmosphere to obtain micron-sized flower-like molybdenum telluride.

[0050] Example 4:

[0051] The method for preparing micron-sized flower-like molybdenum telluride in this embodiment includes:

[0052] Telluric acid was added to deionized water to prepare solution A with a tellurium ion concentration of 0.03 mol / L; sodium molybdate was added to deionized water to prepare solution B with a molybdenum ion concentration of 0.01 mol / L. Solution B was then added dropwise to solution A at a volume ratio of 1:3, followed by the addition of 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture with a 2-amino-3-(4-hydroxyphenyl)propionic acid concentration of 0.03 mol / L. The mixture was placed in a microwave reactor and reacted at 380 W for 14 minutes. After the reaction, the resulting crude solid product was collected. The crude solid product was washed four times with deionized water and then dried at 70 °C for 9 hours. Finally, it was calcined at 480 °C for 2 hours under an argon atmosphere to obtain micron-sized flower-like molybdenum telluride.

[0053] The electrochemical performance of the micron-sized flower-shaped molybdenum telluride prepared in Examples 1-4 as active materials for lithium-ion battery anodes is shown in Table 1.

[0054] Table 1

[0055] Example 1 1.0 500 621 99.7％ Example 2 1.0 500 601 99.5％ Example 3 1.0 500 607 99.6％ Example 4 1.0 500 604 99.4％

[0056] As can be seen from the table above, at a current density of 1 A·g -1 When the number of cycles is 500, the specific capacity of the battery can be maintained at 600 mAh·g after the cycle. -1 The above is higher than the theoretical specific capacity of 372 mAh·g for graphite-based batteries. -1 The reversible capacity retention rate can be above 99.4%, indicating that the micron-sized flower-shaped molybdenum telluride has high specific capacity and good cycle performance as an active material for lithium-ion batteries, thereby improving the energy density and cycle life of lithium-ion batteries.

[0057] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A lithium-ion battery anode material, characterized in that, It contains micron-sized flower-like molybdenum telluride composed of self-assembled two-dimensional nanosheets; The method for preparing the micron-sized flower-shaped molybdenum telluride includes: Step 1: Add the tellurium source and molybdenum source to deionized water to prepare solution A with a tellurium ion concentration of 0.01~0.03 mol / L and solution B with a molybdenum ion concentration of 0.005~0.015 mol / L; Step 2: Add solution B dropwise to solution A, and add 2-amino-3-(4-hydroxyphenyl)propionic acid to obtain a mixture, wherein the volume ratio of solution B to solution A is 1:(1~3), and the concentration of 2-amino-3-(4-hydroxyphenyl)propionic acid in the mixture is 0.01~0.03 mol / L; Step 3: Place the mixture into a microwave reactor for reaction and collect the resulting solid crude product; Step 4: The solid crude product is washed, dried, and calcined under a protective atmosphere to obtain the micron-sized flower-shaped molybdenum telluride.

2. The lithium-ion battery anode material according to claim 1, characterized in that, The thickness of the two-dimensional nanosheet is 1~5 nm.

3. The lithium-ion battery anode material according to claim 1, characterized in that, In step one, the tellurium source includes sodium tellurate and telluric acid, and the molybdenum source includes molybdic acid and sodium molybdate.

4. A lithium-ion battery anode material according to claim 1, characterized in that, In step three, the time of the microwave reactor is set to 10-15 minutes, and the power of the microwave reactor is set to 300-400 W.

5. The lithium-ion battery anode material according to claim 1, characterized in that, In step four, the washing solvent is deionized water, and the washing is performed 3 to 4 times with the deionized water.

6. A lithium-ion battery anode material according to claim 1, characterized in that, In step four, the drying temperature is 50~70 ℃, and the drying time is 6~9 hours.

7. A lithium-ion battery anode material according to claim 1, characterized in that, The calcination temperature is 450~490 ℃, and the calcination time is 2~3 hours.

8. The lithium-ion battery anode material according to claim 1, characterized in that, The protective atmosphere is argon or nitrogen.

9. A method for preparing a lithium-ion battery negative electrode, characterized in that, Using the negative electrode material described in any one of claims 1-8 as the active material of a lithium-ion battery, micron-sized flower-shaped molybdenum telluride is mixed with acetylene black and polyvinylidene fluoride at a mass ratio of 9:0.5:0.

5. After grinding for 10-20 minutes, 20-30 microliters of N-methylpyrrolidone are added, and grinding is continued for another 10-20 minutes. The obtained slurry is coated onto copper foil and vacuum dried at 100°C for 8-10 hours to obtain the negative electrode of the lithium-ion battery.

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