Preparation method and application of sodium ion battery negative electrode material

Abstract

The invention discloses a preparation method and application of a sodium-ion battery negative electrode material, and belongs to the technical field of sodium-ion batteries, and the specific scheme comprises the following steps: step 1, crushing moso bamboo, uniformly mixing the crushed moso bamboo with carbon nanotubes, placing the mixture in a tubular furnace for high-temperature carbonization, and then washing with a KOH solution to obtain an intermediate product A; step 2, uniformly mixing starch, carbon nanotubes and the intermediate product A, placing the mixture in a tubular furnace, and performing high-temperature carbonization to obtain an intermediate product B; and step 3, washing the intermediate product B with HCl and deionized water in sequence until the intermediate product B is neutral, and drying to obtain the sodium-ion battery negative electrode material. Compared with a traditional sodium ion battery negative electrode material, the composite porous carbon material with the high specific surface area has higher specific capacity.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion batteries, and in particular relates to a preparation method and application of a negative electrode material for a sodium ion battery. Background Art

[0002] Sodium-ion batteries have received extensive attention due to their abundant sodium resources and environmental friendliness. Sodium-ion batteries can, to a certain extent, alleviate the problem of limited battery development caused by resource shortages, and are therefore considered to be an ideal choice for the next generation of power sources and energy storage power stations. At present, sodium-ion batteries have advantages such as high energy density. Sodium-ion batteries are composed of five parts: positive electrode, negative electrode, diaphragm, electrolyte, and battery casing. Among them, the negative electrode material is an important component of sodium-ion batteries.

[0003] In the past few decades, people have conducted extensive research on positive electrode materials for sodium-ion batteries, but the research on negative electrode materials for sodium-ion batteries is still in its infancy. In the existing negative electrode material system, although carbon materials have good cycle stability, their mass specific capacity is low and cannot meet the requirements of commercial applications of high-capacity sodium-ion batteries. At present, the negative electrode materials of sodium-ion batteries are still difficult to meet the market demand for various energy storage devices. Therefore, people are in urgent need of developing a new type of electrode material with high specific capacity, high energy density and low price as the negative electrode material of sodium-ion batteries. Summary of the invention

[0004] In order to solve the problem of low specific capacity of negative electrode materials for sodium ion batteries in the prior art, the present invention provides a preparation method and application of negative electrode materials for sodium ion batteries.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a negative electrode material for a sodium ion battery comprises the following steps:

[0007] Step 1: crush the bamboo, mix it with carbon nanotubes, and place it in a tube furnace for the first carbonization, and then wash it with KOH solution to obtain an intermediate product A;

[0008] Step 2: Mix starch, carbon nanotubes and intermediate product A evenly and place in a tube furnace for a second carbonization to obtain intermediate product B;

[0009] Step 3: The intermediate product B is washed with HCl and deionized water in turn until it is neutral, and then dried to obtain a negative electrode material for a sodium ion battery.

[0010] Furthermore, the concentration of the KOH solution is 0.1-10 mol / L, and the concentration of the HCl is 0.1-10 mol / L.

[0011] Furthermore, in step 1 and step 2, the atmosphere of the tube furnace is nitrogen.

[0012] Furthermore, in step 1, the temperature of the first carbonization is 100°C-300°C, and the time is 1-6h.

[0013] Furthermore, in step 2, the temperature of the second carbonization is 600°C-1200°C, and the time is 1-6h.

[0014] Furthermore, the mass ratio of bamboo, carbon nanotubes and starch ranges from 1:0.1:0.1 to 1:2:2.

[0015] Furthermore, the mass ratio of the carbon nanotubes added in step one to the carbon nanotubes added in step two is 1:1.

[0016] Furthermore, in step three, the drying temperature is 50°C-100°C and the time is 2-6h.

[0017] An application of a sodium ion battery negative electrode material prepared by the preparation method in a sodium ion battery.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In the present invention, bamboo charcoal with a porous structure is generated during the carbonization process of moso bamboo; after starch and the bamboo charcoal with a porous structure are mixed, starch particles enter the interior of the porous structure, and in the process of further high-temperature carbonization, starch further generates a fine porous structure inside the bamboo charcoal with a porous structure, so that the specific surface area of ​​the prepared negative electrode material is further expanded within a fixed space; carbon nanotubes are interspersed and penetrated in these porous carbon structures, so as to further increase the specific surface area of ​​the prepared negative electrode material, thereby increasing more sodium storage sites; in addition, the purpose of adding carbon nanotubes in step one and step two of the present invention is that in each step of high-temperature carbonization, the carbon nanotubes support the entire porous carbon structure, prevent the three-dimensional structure of the porous carbon from collapsing, and are more conducive to the stability of the porous carbon structure generated by carbonizing the starch coated inside the bamboo charcoal with a porous structure.

[0020] The composite porous carbon material with a high specific surface area prepared by the present invention has higher electrochemical performance than traditional sodium ion battery negative electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the specific capacity and voltage curve of Example 1;

[0022] Figure 2 is the specific capacity and voltage curve of Example 2;

[0023] Figure 3 is the specific capacity and voltage curve of Example 3;

[0024] Figure 4 This is a curve of specific capacity and constant current charge and discharge times of Example 1. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing a negative electrode material for a sodium ion battery comprises the following steps:

[0028] Step 1: 1g of bamboo was crushed, mixed with 0.1g of carbon nanotubes, and then placed in a tube furnace, carbonized at 100°C for 1h under a nitrogen atmosphere, and then washed with a 0.1mol / L KOH solution to remove lignin and hemicellulose, thereby obtaining an intermediate product A;

[0029] Step 2: 1 g starch, 0.1 g carbon nanotubes and intermediate product A were mixed evenly and placed in a tube furnace, and carbonized at 600° C. for 1 h under a nitrogen atmosphere to obtain intermediate product B;

[0030] Step 3: The intermediate product B is washed with 0.1 mol / L HCl and deionized water in turn until it is neutral, and dried at 50° C. for 6 h to obtain a negative electrode material for a sodium ion battery.

[0031] Example 2

[0032] A method for preparing a negative electrode material for a sodium ion battery comprises the following steps:

[0033] Step 1: 1g of bamboo was crushed, mixed with 0.5g of carbon nanotubes, and then placed in a tube furnace, carbonized at 200°C for 3h under a nitrogen atmosphere, and then washed with 1mol / L KOH solution to remove lignin and hemicellulose, thereby obtaining an intermediate product A;

[0034] Step 2: 1 g starch, 0.5 g carbon nanotubes and intermediate product A were mixed evenly and placed in a tube furnace, and carbonized at 900° C. for 3 h under a nitrogen atmosphere to obtain intermediate product B;

[0035] Step 3: The intermediate product B is washed with 1 mol / L HCl and deionized water in turn until it becomes neutral, and dried at 80° C. for 4 h to obtain a negative electrode material for a sodium ion battery.

[0036] Example 3

[0037] A method for preparing a negative electrode material for a sodium ion battery comprises the following steps:

[0038] Step 1: 1g of bamboo was crushed, mixed evenly with 1g of carbon nanotubes, and then placed in a tube furnace, carbonized at 300°C for 6h under a nitrogen atmosphere, and then washed with 1mol / L KOH solution to remove lignin and hemicellulose, thereby obtaining an intermediate product A;

[0039] Step 2: 1 g starch, 1 g carbon nanotubes and intermediate product A were mixed evenly and then placed in a tubular furnace for carbonization at 1000° C. for 6 h under a nitrogen atmosphere to obtain intermediate product B;

[0040] Step 3: The intermediate product B is washed with 5 mol / L HCl and deionized water in turn until it becomes neutral, and dried at 100° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0041] Comparative Example 1

[0042] Step 1: 1 g of bamboo was crushed and placed in a tubular furnace, carbonized at 300° C. for 6 h under a nitrogen atmosphere, and then washed with 1 mol / L KOH solution to remove lignin and hemicellulose to obtain an intermediate product A;

[0043] Step 2, placing the intermediate product A in a tubular furnace under a nitrogen atmosphere at a temperature of 1000° C. for carbonization for 6 h to obtain the intermediate product B;

[0044] Step 3: The intermediate product B is washed with 5 mol / L HCl and deionized water in turn until it is neutral, and dried at 100° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0045] Figure 1 , Figure 2 , Figure 3 The specific capacity and voltage curves of Example 1, Example 2 and Example 3 are shown respectively. The specific capacity of Example 1, Example 2 and Example 3 are 275 mAh / g, 273 mAh / g and 269 mAh / g respectively, and the first coulombic efficiency is 91.5%, 91.0% and 90.8% respectively. The specific capacity of bamboo charcoal in Comparative Example 1 is 200 mAh / g, and the carbon nanotubes / porous carbon with more porous structures have better electrochemical performance.

[0046] Figure 4The specific capacity and constant current charge and discharge times curve of Example 1. As shown in the figure, in the initial stage, the electrolyte cannot fully enter the pore structure of the material. As the cycle proceeds, the electrolyte gradually enters the electrode structure, and the specific capacity increases to a certain extent. After 500 cycles, the capacity of the prepared material begins to decay, but the decay is small and can still be maintained at around 265mAh / g, showing relatively excellent cycle stability.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a negative electrode material for a sodium ion battery, characterized in that: The following steps are involved: Step 1: crush the bamboo, mix it with the carbon nanotubes, and then place it in a tube furnace for the first carbonization, and then wash it with a KOH solution to obtain an intermediate product A; Step 2: Mix starch, carbon nanotubes and intermediate product A evenly and place in a tube furnace for a second carbonization to obtain intermediate product B; Step 3: The intermediate product B is washed with HCl and deionized water in turn until it is neutral, and then dried to obtain a negative electrode material for a sodium ion battery.

2. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: The concentration of KOH solution is 0.1-10 mol / L, and the concentration of HCl is 0.1-10 mol / L.

3. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: In step 1 and step 2, the atmosphere of the tube furnace is nitrogen.

4. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: The temperature of the first carbonization in step 1 is 100°C-300°C, and the time is 1-6h.

5. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: The temperature of the second carbonization in step 2 is 600°C-1200°C, and the time is 1-6h.

6. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: The mass ratio of bamboo, carbon nanotubes and starch ranges from 1:0.1:0.1 to 1:2:

2.

7. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: The mass ratio of the carbon nanotubes added in step 1 to the carbon nanotubes added in step 2 is 1:

1.

8. The method for preparing a negative electrode material for a sodium ion battery according to claim 1, characterized in that: In step 3, the drying temperature is 50°C-100°C and the time is 2-6 hours.

9. Use of a sodium ion battery negative electrode material prepared by the preparation method according to any one of claims 1 to 8 in a sodium ion battery.

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