A method for preparing a lithium ion battery negative electrode material by using negative electrode production waste

Abstract

The application discloses a method for preparing a lithium ion battery negative electrode material by using negative electrode production waste materials, and comprises the following steps: S1, adding the negative electrode production waste materials with a D50 particle size of 1-3 microns into a mixing pot, adding special pitch, and then uniformly mixing at normal temperature to obtain a mixture; S2, heating and reconstructing, gradually heating the mixture, uniformly mixing in the mixing pot, continuously heating to 430-450 DEG C, and then obtaining negative electrode material raw materials after mixing treatment; and S3, carbonizing and graphitizing the negative electrode material raw materials, and then obtaining the lithium ion battery negative electrode material after screening and magnetic removal. The application greatly reduces the raw material cost and improves the added value of the negative electrode production waste materials.

Description

Technical Field

[0001] This invention relates to the field of anode material technology, and more specifically, to a method for preparing lithium-ion battery anode materials using anode production waste. Background Technology

[0002] Anode materials are one of the key raw materials for lithium-ion batteries, significantly impacting their energy density, cycle performance, charge / discharge rate, and low-temperature discharge performance. Currently, the anode material market suffers from structural oversupply, with major companies continuously expanding their scale and increasing production capacity to seize market share. However, downstream battery manufacturers are still reducing production and clearing inventory, a process expected to continue for some time. Furthermore, downstream battery manufacturers are engaging in low-price sales, leading to persistently weak demand for anode materials in the short term, exacerbating the supply-demand imbalance. Under the dual pressures of overcapacity and declining demand in the anode material market, overall market trading has tightened, and orders are decreasing. To secure orders, many small and medium-sized anode material companies are lowering prices, further reducing the actual transaction price of anode materials.

[0003] In recent years, the rise of the new energy vehicle industry and the development of products such as lithium batteries have driven the continuous expansion of the anode material market. However, the current anode material market is showing a weak and stable trend. In the absence of obvious favorable factors to support the anode material market, technological iteration and cost control capabilities will become the key to companies breaking through.

[0004] Therefore, given the structural overcapacity of lithium-ion battery anode materials, the development of low-cost lithium-ion battery anode materials is beneficial for companies to gain an advantage in cost competition. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for preparing lithium-ion battery anode materials using waste materials from anode production. By using waste materials from anode production as raw materials, and through mixing, reconstructing, carbonization, and graphitization, a stable lithium-ion battery anode material is obtained, which greatly reduces the cost of raw materials and increases the added value of waste materials from anode production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for preparing lithium-ion battery anode materials using waste materials from anode production, comprising the following steps:

[0008] S1, add the waste material from the negative electrode production with a D50 particle size of 1-3μm into the mixing pot, add special asphalt, and then mix evenly at room temperature to obtain a mixture;

[0009] S2, Heating and Reconstruction: The mixture is gradually heated and thoroughly mixed in a kneading pot. The temperature is then increased to 430-450°C. After kneading, the negative electrode material raw material is obtained.

[0010] S3 involves carbonizing and graphitizing the raw materials for the negative electrode, followed by sieving and demagnetization to obtain the negative electrode material for lithium-ion batteries.

[0011] Preferably, in step S1, the waste material from the negative electrode production is selected from one or more of petroleum coke, pitch coke, needle coke, and graphitized coke.

[0012] Preferably, in step S1:

[0013] The special asphalt is selected from isotropic or anisotropic asphalt with a softening point of 150-280℃.

[0014] The D50 particle size of the special asphalt is 1–3 μm.

[0015] Preferably, in step S1, the mass percentage content of the negative electrode production waste material in the mixture is 90-95%, and the mass percentage content of the special asphalt is 5-10%.

[0016] Preferably, in step S2, the gradual heating treatment temperature of the mixture is the softening point of the special asphalt + (60~100)℃.

[0017] Preferably, in step S2, the kneading process takes 3 to 6 hours.

[0018] Preferably, in step S2, the D50 particle size of the negative electrode material raw material is 10-30 μm.

[0019] Preferably, in step S3, the capacity of the lithium-ion battery anode material is ≥345mAh / g, the coulombic efficiency is ≥98%, and the OI value is <2.

[0020] The effects of this invention are as follows:

[0021] 1. The raw materials used in this invention are waste materials from the production of negative electrodes. Through structural reforming, new lithium-ion battery negative electrode materials are obtained, which greatly reduces the cost of raw materials.

[0022] 2. This invention achieves the purpose of reducing the OI value (characterizing the orientation of the material) of the material by reconstructing the waste material produced in the negative electrode production process, which is beneficial to obtaining a negative electrode material with better kinetic performance;

[0023] 3. The waste materials used in this invention are mixed, reconstructed, carbonized, and graphitized to obtain different anode products with stable quality, which greatly improves the added value of anode material waste. Attached Figure Description

[0024] Figure 1 This is a schematic flowchart of the method for preparing lithium-ion battery anode materials using anode production waste materials according to the present invention;

[0025] Figure 2 This is a structural reconstruction diagram of the waste material from the negative electrode production process in the method for preparing lithium-ion battery negative electrode materials using waste material from negative electrode production according to the present invention. Detailed Implementation

[0026] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] Combination Figure 1 , Figure 2 As shown, the present invention provides a method for preparing lithium-ion battery anode materials using waste materials from anode production, comprising the following steps:

[0028] S1, add the waste material from the negative electrode production with a D50 particle size of 1-3μm into the mixing pot, add special asphalt, and then mix evenly at room temperature to obtain a mixture;

[0029] This step is the ambient temperature mixing stage, using waste materials from the negative electrode production as raw materials. For example, one or more of petroleum coke, pitch coke, needle coke, and graphitized coke can be selected. The D50 particle size of the waste materials from the negative electrode production is 1–3 μm. Special asphalt is selected from isotropic or anisotropic asphalt with a softening point of 150–280℃.

[0030] In the mixture, the mass percentage content of waste material from the negative electrode production is 90-95%, and the mass percentage content of special asphalt is 5-10%; the specific amount of special asphalt added can be determined according to the particle size of the negative electrode material raw material produced in step S2.

[0031] S2, Heating and Reconstruction: The mixture is gradually heated and thoroughly mixed in a kneading pot. The temperature is then increased to 430-450°C. After kneading, the negative electrode material raw material is obtained.

[0032] This step involves reconstructing the structure of the waste material from the negative electrode production process during the heating phase. The mixture is gradually heated to a specific temperature, namely the softening point of the special asphalt + (60–100)℃, ensuring thorough and uniform mixing within the kneading pan. The mixture in the kneading pan is then further heated to 430–450℃ according to a programmed procedure and kneaded for 3–6 hours to obtain a negative electrode material raw material with a D50 particle size of 10–30 μm.

[0033] S3 involves carbonizing and graphitizing the raw materials for the negative electrode, followed by sieving and demagnetization to obtain the negative electrode material for lithium-ion batteries.

[0034] In this step, the carbonization temperature of the anode material raw material is 1100-1400℃ and the treatment time is 2-4h; the graphitization temperature is 2700-3000℃ and the treatment time is >8h; after graphitization, the anode material raw material is screened and demagnetized to obtain a stable lithium-ion battery anode material.

[0035] The lithium-ion battery anode material prepared above has a capacity ≥345mAh / g, a coulombic efficiency ≥98% (e.g., a coulombic efficiency of 98% to 99%), and an OI value <2.

[0036] This invention reduces the OI value (characterizing the material's orientation) of the negative electrode by reconstructing the waste material from the aforementioned negative electrode production. The orientation degree OI = I(004) / I(110), which can be calculated using XRD data and is not isotropic. The magnitude of this orientation degree OI value directly affects the electrolyte wetting of the negative electrode, surface impedance, high-rate charge and discharge performance, and also directly affects the expansion of the negative electrode during cycling. The lithium-ion battery negative electrode material prepared by this invention has an OI value <2, which improves the orientation of graphite (i.e., reduces the OI value), which is beneficial for obtaining negative electrode materials with better kinetic performance (the OI value of artificial graphite is greater than 2, the OI of natural graphite is greater than 5, the OI value of composite materials is 3 to 4, and the OI of PV-6 material electrode sheets is the lowest, generally 1 to 1.5).

[0037] Example 1

[0038] The method for preparing lithium-ion battery anode materials using anode production waste in this embodiment is as follows:

[0039] The waste material used in the production of negative electrodes is calcined coal-based needle coke waste gas powder (D50 = 2μm), accounting for 94% by mass. 6% of this powder is added to a special asphalt (isotropic asphalt with a softening point of 210℃). The mixture is then thoroughly mixed in a kneading pan at room temperature. The mixture is gradually heated to 280℃ and thoroughly mixed in the kneading pan. The temperature is then gradually increased to 450℃, and the mixture is kneaded for 5 hours. After cooling, a negative electrode material with a D50 of 16μm is obtained. This material is then carbonized at 1100–1400℃ for 2–4 hours and graphitized at 2700–3000℃ for >8 hours to obtain a preliminary negative electrode material. After sieving and demagnetization, a high-rate lithium-ion battery negative electrode material with a capacity of 355mAh / g, a coulombic efficiency of 98.3%, and an OI value of 1.9 is obtained.

[0040] Example 2

[0041] The method for preparing lithium-ion battery anode materials using anode production waste in this embodiment is as follows:

[0042] The waste material used in the production of negative electrodes is calcined coal-based needle coke waste gas powder (D50 = 3μm), accounting for 95% by mass. 5% of this powder is added to a special asphalt (isotropic asphalt with a softening point of 250℃). The mixture is then thoroughly mixed in a kneading pan at room temperature. The mixture is gradually heated to 320℃ and thoroughly mixed in the kneading pan. The temperature is then gradually increased to 440℃, and the mixture is kneaded for 6 hours. After cooling, a negative electrode material with a D50 of 18μm is obtained. This material is then carbonized at 1100–1400℃ for 2–4 hours and graphitized at 2700–3000℃ for >8 hours to obtain a preliminary negative electrode material. After sieving and demagnetization, a high-rate lithium-ion battery negative electrode material with a capacity of 345mAh / g, a coulombic efficiency of 98.3%, and an OI value of 1.87 is obtained.

[0043] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing lithium-ion battery anode materials using waste materials from anode production, characterized in that, Includes the following steps: S1, add the waste material from the negative electrode production with a D50 particle size of 1-3μm into the mixing pot, add special asphalt, and then mix evenly at room temperature to obtain a mixture; S2, Heating and Reconstruction: The mixture is gradually heated and thoroughly mixed in a kneading pot. The temperature is then increased to 430-450°C. After kneading, the negative electrode material raw material is obtained. S3 involves carbonizing and graphitizing the raw materials for the negative electrode, followed by sieving and demagnetization to obtain the negative electrode material for lithium-ion batteries.

2. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that, In step S1, the waste material from the negative electrode production is selected from one or more of petroleum coke, pitch coke, needle coke, and graphitized coke.

3. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that, In step S1: The special asphalt is selected from isotropic or anisotropic asphalt with a softening point of 150-280℃. The D50 particle size of the special asphalt is 1–3 μm.

4. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that: In step S1, the mass percentage content of the negative electrode production waste material in the mixture is 90-95%, and the mass percentage content of the special asphalt is 5-10%.

5. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that: In step S2, the gradual heating treatment temperature of the mixture is the softening point of the special asphalt + (60~100)℃.

6. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that: In step S2, the kneading process takes 3 to 6 hours.

7. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that: In step S2, the D50 particle size of the negative electrode material raw material is 10-30 μm.

8. The method for preparing lithium-ion battery anode materials using anode production waste as described in claim 1, characterized in that: In step S3, the capacity of the lithium-ion battery anode material is ≥345mAh / g, the coulombic efficiency is ≥98%, and the OI value is <2.

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