Preparation method of bamboo powder biomass carbon lithium ion battery negative electrode material

Abstract

The invention provides a preparation method and application of a bamboo powder biomass carbon negative electrode material, and relates to the field of electrochemistry and new energy materials. The preparation method of the bamboo powder biomass carbon negative electrode material comprises the following steps: S1, weighing bamboo powder, washing with deionized water and ethanol, and drying in a drying oven to obtain a carbon precursor; s2, activating the dried bamboo powder by using a KOH solution, stirring, filtering and drying to obtain a carbonized precursor; s3, putting the carbonized precursor obtained in the step S2 into a crucible, and treating the carbonized precursor under a high-temperature condition and in a protective atmosphere to obtain a porous carbonized product; and S4, carrying out acid pickling on the porous carbon material by using an acid solution, washing the product to be neutral by using deionized water, and drying to obtain the bamboo powder biomass carbon negative electrode material. The bamboo powder biomass carbon negative electrode material is used for preparing lithium ion battery negative electrode slurry. The method has the advantages that renewable and environment-friendly biomass is used as a carbon source, and the method is environment-friendly, simple in preparation process, suitable for large-scale production and the like.

Description

Technical Field

[0001] The present invention relates to the fields of electrochemistry and new energy materials, and specifically to a preparation method of a negative electrode material for a lithium-ion battery based on bamboo powder biomass carbon. Background Art

[0002] With the rapid development of the economy, the demand for energy is also increasing day by day. Lithium-ion batteries have been widely used in reality due to their advantages such as high energy density, high working voltage, no memory effect, and long cycle life.

[0003] In lithium-ion batteries, the most widely commercially used negative electrode material is graphite negative electrode material. However, graphite mainly comes from non-renewable and increasingly depleted fossil raw materials, and its performance is also increasingly difficult to meet people's needs. Therefore, biomass carbon, as an active material for an efficient, cheap, and environmentally friendly energy storage system, has attracted extensive attention.

[0004] Bamboo is a plant with rapid growth and strong renewable ability. It has a short growth cycle, high yield, and is easy to plant and harvest. The carbon materials derived from bamboo have a high surface area and pore volume, which is conducive to the rapid transmission of ions and electrons and reduces the diffusion resistance of lithium ions. Through specific preparation processes, such as high-temperature activation, doping, etc., the conductivity of the carbon materials derived from bamboo can be further improved, thereby improving the electrochemical performance of lithium-ion batteries. With the continuous expansion of the lithium-ion battery market, the demand for negative electrode materials is also increasing. As a renewable and environmentally friendly biomass resource, bamboo has great potential to become a negative electrode material for lithium-ion batteries. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies in current lithium-ion battery technology and provide a preparation method of a negative electrode material for a lithium-ion battery based on bamboo powder biomass carbon, so as to solve the defects of existing graphite negative electrode materials such as high cost, low capacity, and complex production process.

[0006] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0007] A preparation method of a negative electrode material for a lithium-ion battery based on bamboo powder biomass carbon, comprising the following steps:

[0008] S1. Weigh an appropriate amount of bamboo powder, wash it with deionized water and ethanol, and after washing, place it in a drying oven for drying for 12 h to obtain a carbon precursor;

[0009] S2. Activate the dried bamboo powder with a KOH solution, stir for 24 h and then filter, and after drying, obtain a carbonized precursor;

[0010] S3. Place the carbonization precursor obtained in step S2 in a clean crucible, put the crucible into a tube furnace, and treat it under high temperature conditions and in a protective atmosphere to obtain a carbonized product;

[0011] S4. Wash the porous carbon material obtained in step S3 with an acid solution, wash the product with deionized water until it is neutral, and dry it to obtain a bamboo powder biomass carbon anode material for lithium-ion batteries.

[0012] Further, the drying temperature in steps S1, S2, and S3 is 80-100 °C.

[0013] Further, the concentration of the KOH solution in step S2 is 1-3 mol / L.

[0014] Further, the calcination temperature in step S3 is 600-1000 °C, the calcination time is 1-3 hours, and the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.

[0015] Further, the acid solution used for pickling in step S4 is hydrochloric acid or nitric acid, and adding the acid solution can neutralize the material to neutral.

[0016] The present invention also provides the application of the bamboo powder biomass carbon anode material for lithium-ion batteries prepared by the above preparation method in the preparation of an anode slurry for lithium-ion batteries.

[0017] Further, the bamboo powder biomass carbon anode material for lithium-ion batteries is mixed with conductive carbon black and polyvinylidene fluoride in a mass ratio of 8:1:1, and then an appropriate amount of N-methylpyrrolidone is added and stirred for 5 hours to obtain an anode slurry for lithium-ion batteries.

[0018] Coat the above slurry on a copper foil, vacuum dry it at 90 °C for 12 hours, and cut it on a punching machine to obtain a bamboo powder biomass carbon material electrode sheet; use the obtained electrode as the anode.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] 1. Using biomass bamboo powder as a carbon source, bamboo grows rapidly, has strong renewable ability, a short growth cycle, high yield, and is easy to plant and harvest. As a raw material source, it is rich and inexpensive.

[0021] 2. The biomass carbon anode material prepared with bamboo powder as a precursor has a high surface area and pore volume, which is conducive to the rapid transmission of ions and electrons, reduces the diffusion resistance of lithium ions, and thus improves the capacity, rate performance, and cycle performance of lithium-ion batteries.

[0022] 3. Using a renewable and environmentally friendly biomass as a carbon source, it is environmentally friendly and has a simple preparation process, suitable for large-scale production. Description of the Drawings

[0023] Figure 1 It is the preparation flow chart of the anode material of the bamboo powder biomass carbon lithium-ion battery in a specific embodiment of the present invention.

[0024] Figure 2 It is the XRD pattern of the anode material of the bamboo powder biomass carbon lithium-ion battery in a specific embodiment of the present invention. Specific Embodiment

[0025] The following are specific examples of the present invention and in combination with the accompanying drawings, the technical solutions of the present invention are further described, but the present invention is not limited to these examples.

[0026] Example 1

[0027] Prepare the anode material of the bamboo powder biomass carbon lithium-ion battery activated by 1mol / L KOH solution according to the following steps:

[0028] S1. Weigh 5g of bamboo powder and soak it in a mixed solution of 100mL of deionized water and ethanol for 15min. After filtration, wash it repeatedly with deionized water. The bamboo powder after the last washing and filtration is placed in a drying oven at 90°C and dried for 12h.

[0029] S2. Prepare 1mol / L KOH solution, add the dried bamboo powder in step S2 into the KOH solution, stir for 24h and then filter. The filtered solid is placed in a drying oven at 90°C for 12h to obtain a carbonization precursor.

[0030] S3. Load the carbonization precursor obtained in step S2 into a crucible and place it in a tube furnace. Heat it to 800°C at a rate of 10°C / min under a nitrogen atmosphere, keep it at a constant temperature for 90min, and then naturally cool it to room temperature to obtain a carbonization product.

[0031] S4. Put the carbonization product obtained in step S3 into a beaker, add deionized water, add HCL to the beaker, and use a pH test paper to test its pH value until the solution is neutral. After filtration, wash it repeatedly with deionized water, then filter, and place it in a drying oven at 90°C and dry for 12h to obtain the anode material of the bamboo powder biomass carbon lithium-ion battery activated by 1mol / L KOH solution.

[0032] Example 2

[0033] Prepare the anode material of the bamboo powder biomass carbon lithium-ion battery activated by 2mol / L KOH solution according to the following steps:

[0034] S1. Weigh 5g of bamboo powder and soak it in a mixed solution of 100mL of deionized water and ethanol for 15min. After filtration, wash it repeatedly with deionized water. The bamboo powder after the last washing and filtration is placed in a drying oven at 90°C and dried for 12h.

[0035] S2. Prepare a 2 mol / L KOH solution, add the dried bamboo powder from step S2 into the KOH solution, stir for 24 h and then filter. Place the filtered solid in a drying oven at 90 °C for 12 h to obtain a carbonization precursor.

[0036] S3. Load the carbonization precursor obtained in step S2 into a crucible and place it in a tube furnace. Under a nitrogen atmosphere, heat it to 800 °C at a rate of 10 °C / min, keep it at a constant temperature for 90 min, and then naturally cool it to room temperature to obtain a carbonized product.

[0037] S4. Put the carbonized product obtained in step S3 into a beaker, add deionized water, add HCL to the beaker, and use a pH test paper to test its pH value until the solution is neutral. After filtering it, wash it repeatedly with deionized water, then filter it, and place it in a drying oven at 90 °C for 12 h to obtain a negative electrode material of bamboo powder biomass carbon for lithium-ion batteries activated by 2 mol / L KOH solution.

[0038] Example 3

[0039] Prepare a negative electrode material of bamboo powder biomass carbon for lithium-ion batteries activated by 3 mol / L KOH solution according to the following steps:

[0040] S1. Weigh 5 g of bamboo powder and soak it in a mixed solution of 100 mL of deionized water and ethanol for 15 min. After filtering, wash it repeatedly with deionized water. Place the bamboo powder after the last washing and filtering in a drying oven at 90 °C for 12 h.

[0041] S2. Prepare a 3 mol / L KOH solution, add the dried bamboo powder from step S2 into the KOH solution, stir for 24 h and then filter. Place the filtered solid in a drying oven at 90 °C for 12 h to obtain a carbonization precursor.

[0042] S3. Load the carbonization precursor obtained in step S2 into a crucible and place it in a tube furnace. Under a nitrogen atmosphere, heat it to 800 °C at a rate of 10 °C / min, keep it at a constant temperature for 90 min, and then naturally cool it to room temperature to obtain a carbonized product.

[0043] S4. Put the carbonized product obtained in step S3 into a beaker, add deionized water, add HCL to the beaker, and use a pH test paper to test its pH value until the solution is neutral. After filtering it, wash it repeatedly with deionized water, then filter it, and place it in a drying oven at 90 °C for 12 h to obtain a negative electrode material of bamboo powder biomass carbon for lithium-ion batteries activated by 3 mol / L KOH solution.

[0044] Comparative Example 1

[0045] Prepare a negative electrode material of unactivated bamboo powder biomass carbon for lithium-ion batteries according to the following steps:

[0046] S1. Weigh 5 g of bamboo powder and soak it in a mixed solution of 100 mL of deionized water and ethanol for 15 min. After filtration, wash it repeatedly with deionized water. The bamboo powder after the last washing and filtration is placed in an oven at 90 °C and dried for 12 h.

[0047] S2. Load the bamboo powder obtained in step S1 into a crucible and place it in a tube furnace. Under a nitrogen atmosphere, heat it to 800 °C at a rate of 10 °C / min, keep it at a constant temperature for 90 min, and then cool it naturally to room temperature to obtain a carbonized product.

[0048] S4. Put the carbonized product obtained in step S3 into a beaker, add deionized water, wash it repeatedly, filter it, and place it in an oven at 90 °C and dry it for 12 h to obtain an unactivated bamboo powder biomass carbon anode material for lithium-ion batteries.

[0049] Example 4

[0050] Mix the bamboo powder biomass carbon anode materials for lithium-ion batteries prepared in the above Examples 1-3 and Comparative Example 1 with conductive carbon black and polyvinylidene fluoride in a mass ratio of 8:1:1, and then add an appropriate amount of N-methylpyrrolidone and stir for 5 h to obtain a lithium-ion battery anode slurry. Coat the lithium-ion battery anode slurry on a copper foil, dry it in a vacuum at 90 °C for 12 h, and cut it into pieces on a punching machine to obtain a bamboo powder biomass carbon material electrode sheet; use the obtained electrode as the anode, a metal lithium sheet as the cathode, the electrolyte as a mixed system containing 1 mol / L of LiPF6 / (EC + DMC) (volume ratio 1:1), and the separator as a microporous polypropylene membrane (Celgard 2400), and assemble it into a button battery in a glove box filled with argon. After standing the lithium-ion button battery for 24 h, perform electrochemical tests with a voltage range of 0.01-1.5 V and test its capacity at a rate of 0.1C. Table 1 shows the electrochemical performance results of different materials.

[0051] Table 1

[0052]

[0053] As can be seen from Table 1, regardless of whether it is activated by KOH solution, the first-cycle discharge specific capacity is higher than the theoretical value of graphite, which is 372 mAh / g. By comparing Comparative Example 1 with Examples 1-3, the electrochemical performance of the bamboo powder biomass carbon material activated by KOH solution is much higher than that of the unactivated one by KOH solution. This is because KOH will react with carbon at a specific temperature during the high-temperature firing of bamboo powder to produce carbonate compounds and gaseous substances. When these gaseous substances escape from the bamboo powder, they will create "holes" in the original places, thus generating micropores, and therefore improving the electrochemical performance of the material.

[0054] By changing the concentration of the activator KOH solution in Examples 1-3 while keeping the other conditions unchanged, it can be obtained that the initial discharge specific capacity and the initial Coulombic efficiency of the material show a trend of first increasing and then decreasing. This is because as the concentration of the KOH solution increases, the etching degree of KOH on bamboo powder during the firing process also continuously increases. When the concentration of the KOH activator is relatively low, the specific surface area of the prepared material increases with the increase of the KOH concentration. However, when its concentration is too high, the carbon material skeleton is prone to fracture, and the specific surface area and electrochemical performance of the material instead decrease accordingly.

[0055] The above experimental results show that: by the method of the present invention, the bamboo powder biomass carbon lithium-ion battery anode material has excellent electrochemical performance, simple preparation process, and broad application prospects.

[0056] As can be seen from the above examples, the present invention provides a bamboo powder biomass carbon lithium-ion battery anode material. The above examples are described in a relatively specific and detailed manner, but should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, several changes and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A preparation method of a bamboo powder biomass carbon anode material, comprising the following steps: S1. Weigh bamboo powder, wash it with deionized water and ethanol, and after washing, put it into a drying oven for drying for 12 h to obtain a carbon precursor; S2. Activate the dried bamboo powder above with a KOH solution, filter it after stirring for 24 h, and obtain a carbonized precursor after drying; S3. Place the carbonized precursor obtained in step S2 in a clean crucible, put the crucible into a tube furnace, and treat it under high temperature conditions and in a protective atmosphere to obtain a porous carbonized product; S4. Pickle the porous carbon material obtained in step S3 with an acid solution, wash the product with deionized water until it is neutral, and dry it to obtain a bamboo powder biomass carbon anode material.

2. The preparation method of the bamboo powder biomass carbon negative electrode material according to claim 1, characterized in that, The drying temperature in steps S1, S2 and S3 is 80-100 °C.

3. The preparation method of the bamboo powder biomass carbon anode material according to claim 1, characterized in that, The concentration of the KOH solution in step S2 is 1-3 mol / L.

4. The preparation method of the bamboo powder biomass carbon anode material according to claim 1, characterized in that, In step S3, the calcination temperature is 600-1000 °C, the calcination time is 1-3 hours, and the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.

5. The preparation method of the bamboo powder biomass carbon anode material according to claim 1, characterized in that, In step S4, the acid solution used for pickling is hydrochloric acid or nitric acid, and adding the acid solution can neutralize the material to be neutral.

6. Use of the bamboo powder biomass carbon negative electrode material prepared according to claim 1, characterized in that, It is applied to the preparation of a lithium-ion battery anode slurry.

7. The application of the bamboo powder biomass carbon anode material according to claim 6, characterized in that, The bamboo powder biomass carbon anode material is mixed with conductive carbon black and polyvinylidene fluoride in a mass ratio of 8:1:1, and then N-methylpyrrolidone is added and stirred for 5 hours to obtain a lithium-ion battery anode slurry.

8. The application of the bamboo powder biomass carbon anode material according to claim 6, characterized in that, The lithium-ion battery anode slurry is coated on a copper foil, vacuum dried at 90 °C for 12 hours, sliced on a punching machine to obtain a bamboo powder biomass carbon material electrode sheet, and the obtained electrode is used as the anode.

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