Preparation method of a negative electrode composite material for a lithium-ion battery

Abstract

The present invention discloses a preparation method of a negative electrode composite material for a lithium-ion battery. Through the present invention, a negative electrode material for a lithium-ion battery composite of metal carbide Ti2AlC / TiO2 / PDA is obtained. The introduction and growth of TiO2 / PDA composite nanoparticles prevent the re-stacking of transition metal carbide nanosheets, thereby maintaining sheet separation; TiO2 has a lower volume expansion during the lithiation process, and the diffusion distance for lithium-ion transport is shorter, solving the problem of internal conductivity of transition metal carbide nanosheets; by combining TiO2 / PDA composite nanoparticles with transition metal carbide nanosheets, the performance of transition metal carbide nanosheets is fully exerted.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and particularly to a preparation method of a negative electrode composite material for a lithium-ion battery. Background Art

[0002] Transition metal carbide Ti2AlC has ultra-high electronic conductivity and excellent charge storage performance. Due to its high volume capacitance ability, it is suitable for energy storage applications. When applied to the negative electrode material of a lithium-ion battery, since the nanosheets of transition metal carbide Ti2AlC are prone to re-stack, it will lead to poor conductivity and slow lithium-ion diffusion within the material, thus limiting the full utilization of its performance. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a preparation method of a negative electrode composite material for a lithium-ion battery.

[0004] The purpose of the present invention is achieved through the following technical solutions: A preparation method of a negative electrode composite material for a lithium-ion battery specifically includes the following steps:

[0005] Step 1: Take 6 g of Ti2AlC material and slowly add it to a large flask containing 200 mL of 20% HF. Stir the obtained mixture gently at room temperature for 24 hours;

[0006] Step 2: Obtain a solid material by vacuum filtering the slurry and the mixture in Step 1. Wash the solid material with 2 L of deionized water until the pH is 6. Collect the wet solid and freeze-dry it to obtain multi-layer transition metal carbide; Step 3: The multi-layer transition metal carbide in Step 2 is further exfoliated by ultrasonic treatment in a water bath in dimethyl sulfoxide (DMSO) for 24 hours, and centrifuged at 3500 rpm for 20 minutes to obtain exfoliated transition metal carbide;

[0007] Step 4: Take 10 g of the exfoliated transition metal carbide in Step 3 and add it to a hydrothermal reactor. Then add 50 mL of 0.5 mol / L ammonia water, 5 g of TiO2 nanoparticles, and 50 mg of dopamine in sequence to obtain a mixed liquid.

[0008] Step 5: Heat and react the mixed liquid obtained in Step 4 at 450 °C for 24 h. After cooling, obtain a solid material by vacuum filtering the slurry, and wash it with 2 L of deionized water until the pH is 7. Collect the wet solid and freeze-dry it to obtain a composite nanomaterial.

[0009] A further technical solution is that the composite nanomaterial obtained in Step 5 is used as the negative electrode material of a lithium-ion battery.

[0010] The present invention has the following advantages:

[0011] (1) Through the preparation method provided by the present invention, a negative electrode material for lithium-ion batteries composite of metal carbide Ti2AlC / TiO2 / PDA can be obtained. The introduction and growth of TiO2 / PDA composite nanoparticles prevent the re-stacking of transition metal carbide nanosheets, thus maintaining sheet separation.

[0012] (2) In the present invention, TiO2 has a lower volume expansion during the lithiation process, and the diffusion distance for lithium-ion transport is shorter, solving the problem of internal conductivity of transition metal carbide nanosheets. Combining TiO2 / PDA composite nanoparticles with transition metal carbide nanosheets significantly improves the performance and fully exerts the performance of transition metal carbide nanosheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a scanning electron microscope photograph of the Ti2AlC / TiO2 / PDA negative electrode material for lithium-ion batteries of the present invention;

[0014] Figure 2 is a transmission electron microscope photograph of the Ti2AlC / TiO2 / PDA negative electrode material for lithium-ion batteries of the present invention;

[0015] Figure 3 is a comparison chart of the cycle performance of the Ti2AlC / TiO2 / PDA of the present invention and a single Ti2AlC battery;

[0016] Figure 4 is a comparison chart of the electrochemical impedance of the Ti2AlC / TiO2 / PDA of the present invention and a single Ti2AlC. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0019] As Figures 1 to 4 shown, a preparation method of a negative electrode composite material for lithium-ion batteries specifically includes the following steps:

[0020] Step 1: Take 6 g of Ti2AlC material and slowly add it to a large flask containing 200 mL of 20% HF. Stir the resulting mixture gently at room temperature for 24 hours;

[0021] Step 2: Obtain the solid material by vacuum filtering the slurry from the mixture in Step 1. Wash the solid material with 2 L of deionized water until the pH is 6. Collect the wet solid and freeze-dry it to obtain multilayer transition metal carbides. Step 3: The multilayer transition metal carbides in Step 2 are further exfoliated by ultrasonic treatment in a water bath in dimethyl sulfoxide (DMSO) for 24 hours and centrifuged at 3500 rpm for 20 minutes to obtain exfoliated transition metal carbides;

[0022] Step 4: Take 10 g of the exfoliated transition metal carbides in Step 3 and add them to a hydrothermal autoclave. Then add 50 mL of 0.5 mol / L ammonia water, 5 g of TiO2 nanoparticles, and 50 mg of dopamine in sequence to obtain a mixed liquid.

[0023] Step 5: Heat the mixed liquid obtained in Step 4 at 450 °C for 24 h. After cooling, obtain the solid material by vacuum filtering the slurry, and wash it with 2 L of deionized water until the pH is 7. Collect the wet solid and freeze-dry it to obtain the Ti2AlC / TiO2 / PDA composite nanomaterial.

[0024] The present invention applies the Ti2AlC / TiO2 / PDA composite nanomaterial to the anode material of a lithium-ion battery. Its scanning electron microscope photos and transmission electron microscope photos are as Figures 1 - 2 shown. The comparison of the battery cycling performance and the electrochemical impedance under the conditions of using the Ti2AlC / TiO2 / PDA composite nanomaterial and the single Ti2AlC material are as Figures 3 - 4 shown. It can be seen from the figure that compared with the single Ti2AlC material, the Ti2AlC / TiO2 / PDA composite material has better cycling efficiency and smaller charge transfer resistance, and thus has better conductivity.

[0025] In the present invention, by adding TiO2 nanoparticles and dopamine (PDA), the growth of TiO2 / PDA composite nanoparticles can prevent the re-stacking of transition metal carbide nanosheets, thereby maintaining sheet separation. TiO2 also exhibits a low volume expansion (<4%) during the lithiation process, and the diffusion distance for lithium ion transport is shorter, solving the problem of internal conductivity of transition metal carbide nanosheets. By combining TiO2 / PDA composite nanoparticles with transition metal carbide nanosheets to produce the Ti2AlC / TiO2 / PDA composite material, the performance of transition metal carbide nanosheets can be fully exerted, thereby improving the performance of the anode material of a lithium-ion battery.

[0026] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a composite anode material for a lithium-ion battery, characterized in that: Specifically, it includes the following steps: Step 1: Take 6 g of Ti2AlC material and slowly add it to a large flask containing 200 mL of 20% HF. Stir the resulting mixture gently at room temperature for 24 hours; Step 2: Obtain the solid material by vacuum filtering the slurry from the mixture in Step 1. Wash the solid material with 2 L of deionized water until the pH is 6. Collect the wet solid and freeze-dry it to obtain multi-layer transition metal carbides; Step 3: The multi-layer transition metal carbides in Step 2 are further exfoliated by ultrasonic treatment in a water bath in dimethyl sulfoxide for 24 hours and centrifuged at 3500 rpm for 20 minutes to obtain exfoliated transition metal carbides; Step 4: Take 10 g of the exfoliated transition metal carbides in Step 3 and add them to a hydrothermal reactor. Sequentially add 50 mL of 0.5 mol / L ammonia water, 5 g of TiO2 nanoparticles, and 50 mg of dopamine to obtain a mixed liquid; Step 5: Heat the mixed liquid obtained in Step 4 at 450 °C for 24 h. After cooling, obtain the solid material by vacuum filtering the slurry, and wash it with 2 L of deionized water until the pH is 7. Collect the wet solid and freeze-dry it to obtain the composite nanomaterial.

2. The preparation method of a negative electrode composite material for a lithium-ion battery according to claim 1, characterized in that: The composite nanomaterial obtained in Step 5 is used as the anode material for lithium-ion batteries.

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