A multi-walled carbon nanotube material for sodium ion battery negative electrode and preparation method

Abstract

The present invention belongs to the field of material preparation and negative electrode materials for sodium ion batteries, and discloses a multi-walled carbon nanotube material for the negative electrode of a sodium ion battery and a preparation method. The preparation method comprises: mixing a carbon-based raw material with a saturated salt water to obtain a mixed material; filtering and separating the mixed material to obtain a carbon-based raw material infiltrated with salt, and drying to obtain a dried carbon-based raw material; and sequentially carbonizing, acid etching, washing and vacuum drying the dried carbon-based raw material to obtain a multi-walled carbon nanotube material. The multi-walled carbon nanotube material of the present invention has a good multi-walled tubular structure and has excellent application prospects in sodium ion batteries.

Description

Technical Field

[0001] The present invention belongs to the field of material preparation and sodium ion battery negative electrode material, and more specifically, relates to a multi-walled carbon nanotube material for a sodium ion battery negative electrode and a preparation method thereof. Background Art

[0002] With the prevalence of energy conversion and storage technologies in sustainable development, sodium-ion batteries have attracted widespread attention in the battery industry due to their abundant sodium resources and low cost. Most of the research on sodium-ion batteries focuses on positive electrode materials, but the development of negative electrode materials with excellent performance and practicality is particularly important for the practical application of sodium-ion batteries. Among them, the negative electrode materials of sodium-ion batteries mainly include: carbon-based materials, alloy materials, titanium-based materials, organic compound materials and other material systems. Carbon-based materials have abundant resources and mature technologies, making it easier to realize the industrialization of technology.

[0003] As a potential negative electrode material for sodium ion batteries, the structural characteristics of carbon-based materials have a great influence on energy storage performance. Nanostructured carbon materials (nanowires, nanosheets, nanotubes, etc.) have good conductivity and structural stability, and the large specific surface area of ​​nanomaterials can reduce the diffusion path of ions to improve electrocatalytic performance. Among them, carbon nanotubes, especially multi-walled carbon nanotubes, have broad application prospects in catalysis, environmental science, energy storage and conversion, etc. due to their unique metal or semiconductor conductivity, good adsorption capacity and excellent field electron emission performance. At present, industrialization mainly uses CVD method to grow carbon nanotubes. However, due to its low growth temperature and low degree of graphitization, it leads to many structural defects, which seriously restricts the performance of their excellent performance. Biomass can be used as a good carbon source for the preparation of carbon materials. Therefore, it is urgent to propose a method for preparing multi-walled carbon nanotube materials based on biomass and its application as negative electrode materials for sodium ion batteries. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and to propose a multi-walled carbon nanotube material and a preparation method for a negative electrode of a sodium ion battery. The multi-walled carbon nanotube material of the present invention has a good multi-walled tubular structure and has excellent application prospects in sodium ion batteries.

[0005] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a multi-walled carbon nanotube material for a negative electrode of a sodium ion battery, the preparation method comprising the following steps:

[0006] S1: mixing the carbon-based raw material with saturated salt water to obtain a mixed material;

[0007] S2: filtering and separating the mixed material to obtain a carbon-based raw material impregnated with salt, and drying the mixed material to obtain a dried carbon-based raw material;

[0008] S3: sequentially subjecting the dried carbon-based raw material to carbonization treatment, acid etching treatment, washing and vacuum drying to obtain the multi-walled carbon nanotube material.

[0009] According to the present invention, preferably, the carbon-based raw material is at least one of cotton, reed and catkins.

[0010] According to the present invention, preferably, the usage ratio of the carbon-based raw material to saturated brine is (1.5-2.5): (50-80) g / mL.

[0011] According to the present invention, preferably, the mixing time is 36-48 hours.

[0012] According to the present invention, preferably, the drying time is 8-24 hours.

[0013] According to the present invention, preferably, the carbonization treatment conditions include: the carbonization treatment time is 2-3h, carried out under N2 atmosphere protection, the heating rate is 3-5°C / min, and the carbonization treatment temperature is 800-1000°C.

[0014] In the present invention, as a preferred embodiment, the equipment used for the carbonization treatment is a tubular furnace.

[0015] According to the present invention, preferably, the solvent used in the acid etching treatment is a 0.8-1.0 mol / L nitric acid aqueous solution, and the time of the acid etching treatment is 24-36 h.

[0016] In the present invention, as a preferred embodiment, the washing is washing with deionized water and ethanol 2-3 times.

[0017] According to the present invention, preferably, the vacuum drying temperature is 55-65°C.

[0018] The second aspect of the present invention provides a multi-walled carbon nanotube material prepared by the method for preparing the multi-walled carbon nanotube material for the negative electrode of a sodium ion battery.

[0019] The beneficial effects of the technical solution of the present invention are as follows:

[0020] The multi-walled carbon nanotube material of the present invention has a multi-walled tubular structure and has excellent application prospects in sodium ion batteries;

[0021] The multi-walled carbon nanotube material of the present invention can be used as a carbon substrate for the negative electrode material of sodium ion batteries, and has good catalytic activity and cycle stability;

[0022] The preparation process of the invention is simple, the cost is low, the purity of the target product is high, and it is conducive to mass production and large-scale production, and is conducive to promotion in battery applications.

[0023] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0025] Figure 1 The XRD spectra of the multi-walled carbon nanotube materials prepared in Examples 1, 2, 3, and 4 of the present invention are shown (wherein "Intensity" is intensity and "2θ (degree)" is angle).

[0026] FIG. 2 (a)-(b) show SEM spectra of multi-walled carbon nanotube materials prepared in Examples 1 and 2 of the present invention ((a) is Example 1; (b) is Example 2).

[0027] Figure 3 The first charge and discharge performance diagram of the multi-walled carbon nanotube material prepared in Example 3 of the present invention as the negative electrode material of the sodium ion battery in the sodium ion battery is shown (wherein, "Potential (V vs. Na / Na + )” is voltage; “Capacity (mAh g -1 )” is the capacity; “1st” is the first time; “2nd” is the second time).

[0028] Figure 4 The charge and discharge rate diagram of the multi-walled carbon nanotube material prepared in Examples 1, 2, 3, and 4 of the present invention as the negative electrode material of the sodium ion battery in the sodium ion battery is shown (wherein, "Cycle number (n)" is the number of cycles). DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0030] Example 1

[0031] This embodiment provides a method for preparing a multi-walled carbon nanotube material, the preparation method comprising the following steps:

[0032] S1: 2.0 g of cotton was soaked in 50 mL of saturated saline for 36 h to obtain a mixed material;

[0033] S2: filtering and separating the mixed material to obtain cotton impregnated with salt, and drying the cotton to obtain dried cotton;

[0034] S3: The dried cotton is placed in a tubular furnace in a N2 atmosphere at 800°C for 2 hours with a heating rate of 3°C / min to obtain a carbonized product; the carbonized product is placed in 50mL of a nitric acid aqueous solution (0.8M), and after acid etching for 24 hours, it is washed with deionized water and ethanol for 3 times, and the washed sample is dried in a vacuum drying oven at 60°C to obtain the multi-walled carbon nanotube material.

[0035] Example 2

[0036] This embodiment provides a method for preparing a multi-walled carbon nanotube material. The difference between this embodiment and embodiment 1 is only that:

[0037] In step S1, 2.0 g of reeds were soaked in 50 mL of saturated saline solution for 48 hours to obtain a mixed material.

[0038] Example 3

[0039] This embodiment provides a method for preparing a multi-walled carbon nanotube material. The difference between this embodiment and embodiment 1 is only that:

[0040] In step S3, the temperature of the carbonization treatment is 1000°C.

[0041] Example 4

[0042] This embodiment provides a method for preparing a multi-walled carbon nanotube material. The difference between this embodiment and embodiment 1 is only that:

[0043] In step S1, 2.0 g of catkins are soaked in 50 mL of saturated salt water for 48 hours to obtain a mixed material;

[0044] In step S3, the heating rate of the carbonization treatment is 5°C / min.

[0045] Example 5

[0046] This embodiment provides a method for preparing a multi-walled carbon nanotube material. The difference between this embodiment and embodiment 1 is only that:

[0047] In step S3, the heating rate of the carbonization treatment is 5°C / min.

[0048] Test Case

[0049] In this test example, the multi-walled carbon nanotube material obtained in Examples 1-4 is used as the negative electrode material of the sodium ion battery, and the performance of the sodium ion battery of this test example is tested.

[0050] The positive electrode material of the sodium ion battery in this test example is transition metal sodium oxide Na x MO2, the electrolyte is sodium hexafluorophosphate.

[0051] The first charge and discharge performance of the multi-walled carbon nanotube material prepared in Example 3 of the present invention as the negative electrode material of the sodium ion battery in the sodium ion battery is as follows: Figure 3 shown.

[0052] The multi-walled carbon nanotube materials prepared in Examples 1, 2, 3, and 4 of the present invention are used as negative electrode materials for sodium ion batteries. The charge and discharge rates in sodium ion batteries are as follows: Figure 4 shown.

[0053] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a multi-walled carbon nanotube material for a negative electrode of a sodium ion battery, characterized in that: The preparation method comprises the following steps: S1: mixing the carbon-based raw material with saturated salt water to obtain a mixed material; S2: filtering and separating the mixed material to obtain a carbon-based raw material impregnated with salt, and drying the mixed material to obtain a dried carbon-based raw material; S3: sequentially subjecting the dried carbon-based raw material to carbonization treatment, acid etching treatment, washing and vacuum drying to obtain the multi-walled carbon nanotube material; The carbon-based raw material is at least one of cotton, reed and catkins; The ratio of the carbon-based raw material to the saturated salt water is (1.5-2.5): (50-80) g / mL; The carbonization treatment conditions include: the carbonization treatment time is 2-3h, carried out under N2 atmosphere protection, the heating rate is 3-5℃ / min, and the carbonization treatment temperature is 800-1000℃; The solvent used in the acid etching treatment is a 0.8-1.0 mol / L nitric acid aqueous solution.

2. The method for preparing the multi-walled carbon nanotube material for the negative electrode of a sodium ion battery according to claim 1, wherein: The mixing time is 36-48h.

3. The method for preparing the multi-walled carbon nanotube material for the negative electrode of a sodium ion battery according to claim 1, wherein: The drying time is 8-24h.

4. The method for preparing the multi-walled carbon nanotube material for the negative electrode of a sodium ion battery according to claim 1, wherein: The acid etching treatment time is 24-36h.

5. The method for preparing the multi-walled carbon nanotube material for the negative electrode of a sodium ion battery according to claim 1, wherein: The vacuum drying temperature is 55-65°C.

6. The multi-walled carbon nanotube material prepared by the method for preparing a multi-walled carbon nanotube material for a negative electrode of a sodium ion battery according to any one of claims 1 to 5.

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