Anode black powder and recovery method thereof

Abstract

The invention provides positive electrode black powder and a recovery method thereof. The positive electrode black powder comprises a ternary material with a layered structure, the positive electrode black powder satisfies: H (003) / H (200) > = 2, H (003) is the peak intensity of a 003 characteristic diffraction peak in an X-ray diffraction pattern of the positive electrode black powder, and H (200) is the peak intensity of a 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder. According to the method, the ratio of the peak intensity of the 003 characteristic diffraction peak to the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder is controlled to be within a certain range, so that the efficiency of recycling and leaching lithium by a wet method is improved, the subsequent recycling process is simplified, and the recycling cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of secondary battery recycling, and in particular to a positive electrode black powder and a recycling method thereof. Background Art

[0002] With the large-scale application of lithium batteries in new energy vehicles and energy storage, a large number of retired lithium batteries are generated, causing great harm to the environment. The recycling of retired lithium batteries can not only avoid environmental pollution and waste of resources, but also bring great economic benefits. In the recycling process of retired lithium batteries, the separation of positive electrode black powder and aluminum foil and the acquisition of positive electrode black powder with high dispersion and low impurity content are the key links to improve the recovery rate of lithium, nickel, cobalt and manganese metals. Summary of the invention

[0003] The purpose of the present application is to provide a positive electrode black powder and a recovery method thereof, so as to improve the efficiency of wet recovery of leached lithium, simplify the subsequent recovery process, and reduce the recovery cost.

[0004] To achieve the above-mentioned object, in a first aspect of the present application, a positive electrode black powder is provided, wherein the positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

[0005] As an embodiment of the present application, the positive electrode black powder satisfies: 0.05°≤F (003) ≤0.2°, where F (003) It is the half-peak width of the 003 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder.

[0006] As an embodiment of the present application, the positive electrode black powder satisfies: 0.3°≤F (200) ≤1°, where F (200) It is the half-peak width of the 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder.

[0007] As an implementation scheme of the present application, there are at least two characteristic peaks in the particle size distribution diagram of the positive electrode black powder, and there is at least one characteristic peak above 20 μm.

[0008] As an embodiment of the present application, the volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the positive electrode black powder is max Satisfy: 1% ≤ H max ≤5%.

[0009] As an implementation scheme of the present application, the positive electrode black powder contains impurity elements, and the impurity elements include at least one of Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, W, Zr, Ti, La, Nb, Mo, and V, and the total content C of the impurity elements satisfies: C≤3wt%.

[0010] As an embodiment of the present application, the specific surface area B of the positive electrode black powder satisfies: 1m 2 / g≤B≤10m 2 / g.

[0011] As an implementation scheme of the present application, the powder resistivity R of the positive electrode black powder 20KN satisfies: 50Ω*cm≤R≤300Ω*cm.

[0012] As an embodiment of the present application, the positive electrode black powder 30KN powder compaction density D satisfies: 2.5g / cm 3 ≤D≤4g / cm 3 .

[0013] The second aspect of the present application provides a method for recovering positive electrode black powder, comprising the following steps:

[0014] S1. Discharging the retired lithium-ion battery and disassembling it to obtain the positive electrode sheet;

[0015] S2. Place the positive electrode sheet into a laser cleaning machine, and clean each surface of the positive electrode sheet for 0.5h to 4h at a laser wavelength of 337nm to 1064nm and a cleaning power of 100W to 2000W, and then sieve to obtain positive electrode black powder;

[0016] The positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

[0017] Compared with the prior art, the beneficial effects of this application are:

[0018] The present invention controls the peak intensity H of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder. (003) The peak intensity of the characteristic diffraction peak is 200 H (200) Satisfaction: H (003) / H (200) ≥2, which improves the efficiency of wet recovery of leached lithium, is conducive to simplifying the subsequent recovery process and reducing the recovery cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The X-ray diffraction pattern (also called XRD pattern) of the positive electrode black powder prepared in Example 1;

[0020] Figure 2 This is the particle size distribution diagram of the positive electrode black powder prepared in Example 1. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0022] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0023] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0024] The reagents or instruments used in this application without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0025] The embodiment of the present application provides a positive electrode black powder, wherein the positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

[0026] The inventors of this application have found that the ratio of the peak intensity of the 003 characteristic diffraction peak to the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder can reflect the content of aluminum impurities in the positive electrode black powder. By controlling the ratio of the two within a certain range, it is beneficial to simplify the subsequent recovery process, reduce the recovery cost, and improve the efficiency of wet recovery and leaching of lithium. The method for obtaining the X-ray diffraction spectrum of the positive electrode black powder in this application is as follows: grind the sample to be tested into powder for 15 minutes, and press it into a uniform thin sheet, then load the sample onto the sample stage of the X-ray diffractometer, and start the X-ray diffractometer to obtain the corresponding X-ray diffraction spectrum. The parameters of the X-ray diffractometer are as follows: target material: Cu target; X-ray measurement wavelength: 1.5406; scanning mode: continuous scanning; starting angle & ending angle: 10°~90°; scanning speed: 10° / min; step size: 0.01°.

[0027] In some embodiments, the positive electrode black powder satisfies: 3.37 ≥ H (003) / H (200) ≥2. For example, H (003) / H (200) It can be 2, 2.12, 2.29, 2.46, 2.94, 3.22, 3.37 or a value in a range consisting of any two of the above points.

[0028] In some embodiments, the positive electrode black powder satisfies: 0.05°≤F (003) ≤0.2°, where F (003) is the half-peak width of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder. For example, the half-peak width of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder can be 0.05°, 0.1°, 0.15°, 0.2°, or a value in the range formed by any two of the above points.

[0029] In some embodiments, the positive electrode black powder satisfies: 0.3°≤F (200) ≤1°, where F (200) is the half-peak width of the 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder. For example, the half-peak width of the 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder can be 0.3°, 0.35°, 0.4°, 0.45°, 0.5°, 0.55°, 0.6°, 0.65°, 0.7°, 0.75°, 0.8°, 0.85°, 0.9°, 0.95°, 1.0°, or a value in the range formed by any two of the above points.

[0030] The half-peak width F of the positive black powder (003) and F (200) It can reflect the crystallinity of the positive electrode active material and aluminum impurities in the black powder respectively. The higher the value, the cleaner the binder is removed and the higher the subsequent leaching efficiency.

[0031] In some embodiments, the particle size distribution diagram of the positive electrode black powder has at least two characteristic peaks, and at least one characteristic peak exists above 20 μm. When the particle size distribution diagram of the positive electrode black powder meets the above conditions, it indicates that the particles have high dispersibility and high subsequent leaching efficiency.

[0032] In some embodiments, the volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the positive electrode black powder is max Satisfy: 1% ≤ H max ≤5%. For example, the volume percentage of the characteristic peak with the largest particle size in the particle size distribution diagram of the positive electrode black powder is H max It can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or a value in a range consisting of any two of the above points. The volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the positive electrode black powder max Within the above range, the particle dispersibility is good and the subsequent leaching efficiency is high.

[0033] In some embodiments, the positive electrode black powder contains impurity elements, and the impurity elements include at least one of Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, W, Zr, Ti, La, Nb, Mo, and V. In some embodiments, the impurity elements include at least one of Al, Cu, Fe, B, Sb, W, Sr, Y, Ti, and Zr.

[0034] In some embodiments, the total content C of the impurity elements satisfies: C≤3 wt %. For example, the total content C of the impurity elements I It can be 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt% or a value in the range formed by any two of the above points. When the total content of impurity elements in the positive electrode black powder is within the above range, it is beneficial to simplify the subsequent recycling process and improve the purity of the recycled product.

[0035] In some embodiments, the specific surface area B of the positive electrode black powder satisfies: 1m 2 / g≤B≤10m 2 / g. For example, the specific surface area B of the positive electrode black powder can be 1m 2 / g, 2m 2 / g, 3m 2 / g, 4m 2 / g, 5m 2 / g, 6m 2 / g, 7m 2 / g, 8m 2 / g, 9m 2 / g, 10m 2 / g or a value in the range formed by any two of the above points. The specific surface area B of the positive electrode black powder is within the above range, which is beneficial to the subsequent leaching of lithium metal elements.

[0036] In some embodiments, the powder resistivity R of the positive electrode black powder 20KN satisfies: 50Ω*cm≤R≤300Ω*cm. The powder resistivity R of the positive electrode black powder 20KN may be 50Ω*cm, 100Ω*cm, 120Ω*cm, 150Ω*cm, 180Ω*cm, 200Ω*cm, 250Ω*cm, 280Ω*cm, 300Ω*cm, or a value in a range formed by any two of the above points. The powder resistivity of the positive electrode black powder is in the above range, which is conducive to the subsequent lithium metal leaching.

[0037] In some embodiments, the positive electrode black powder 30KN powder compaction density D satisfies: 2.5g / cm 3 ≤D≤4g / cm 3 For example, the compacted density D of the positive electrode black powder 30KN can be 2.5g / cm 3 , 2.8g / cm 3 , 3g / cm 3 、3.2g / cm 3 , 3.5g / cm 3 、3.8g / cm 3 , 4g / cm 3 Or a value in the range formed by any two of the above points. The compacted density of the positive electrode black powder is within the above range, which is beneficial to the subsequent leaching of lithium metal.

[0038] The embodiment of the present application also provides a method for recovering positive electrode black powder, comprising the following steps:

[0039] S1. Discharging the retired lithium-ion battery and disassembling it to obtain the positive electrode sheet;

[0040] S2. Place the positive electrode sheet into a laser cleaning machine, and clean each surface of the positive electrode sheet for 0.5h to 4h at a laser wavelength of 337nm to 1064nm and a cleaning power of 100W to 2000W, and then sieve to obtain positive electrode black powder;

[0041] The positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

[0042] This application uses laser cleaning to recycle positive electrode black powder. Laser cleaning does not require a cleaning medium, greatly reducing the degree of damage to the aluminum foil, and the aluminum impurity content in the positive electrode black powder is low. In addition, laser cleaning removes the positive electrode black powder from the surface of the current collector aluminum foil through vaporization, shock waves, thermal elasticity, etc. The positive electrode black powder has a high recovery rate and good dispersibility, which significantly improves the subsequent wet leaching efficiency.

[0043] In some embodiments, the cleaning power is 100 to 2000 W. For example, the cleaning power may be 100 W, 150 W, 200 W, 300 W, 500 W, 1000 W, 1500 W, 2000 W, or a value in a range formed by any two of the above points. The laser cleaning power will affect the recycling efficiency and the content of aluminum impurities in the black powder. A suitable power range is conducive to improving the recycling efficiency and reducing the content of aluminum impurities in the black powder.

[0044] In some embodiments, the laser wavelength is 337 to 1064 nm. For example, the laser wavelength can be 337 nm, 488 nm, 514 nm, 543 nm, 550 nm, 570 nm, 659 nm, 694 nm, 1064 nm, or a value in the range formed by any two of the above points. If the laser wavelength is too large, the positive electrode black powder cannot be effectively peeled off from the aluminum foil, and the recovery rate of the positive electrode black powder is low. If the laser wavelength is too small, the aluminum foil is broken and mixed with the positive electrode active material, resulting in an excessively high content of aluminum impurities in the black powder. A suitable laser wavelength can selectively gasify and decompose the binder to achieve the separation of the positive electrode black powder and the aluminum foil without causing significant damage to the aluminum foil.

[0045] In some embodiments, the laser cleaning time is 0.5-4 hours. For example, the laser cleaning time can be 0.5 hours, 0.75 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, or a value in a range formed by any two of the above points. A suitable cleaning time can improve the recovery rate of the positive electrode black powder while not causing significant damage to the aluminum foil.

[0046] The following are specific embodiments of the present application, and the technical scheme of the present application is further described in conjunction with the embodiments, but the present application is not limited to these embodiments. The reagents, methods and equipment used in the present application, unless otherwise specified, are conventional reagents, methods and equipment in the art.

[0047] Example 1

[0048] Embodiment 1 provides a method for recovering positive electrode black powder, comprising the following steps:

[0049] (1) After the retired ternary lithium battery is completely discharged using a discharge device, it is automatically disassembled to obtain the positive electrode sheet, the negative electrode sheet and the separator respectively;

[0050] (2) placing the positive electrode sheet into a laser cleaning machine, and cleaning each side for 0.5 h at a laser wavelength of 1064 nm and a cleaning power of 100 W to obtain a mixture of black powder and aluminum foil;

[0051] (3) The mixture obtained in step 2 was added into a vibrating screening machine with a sieve hole size of 0.1 mm and a screening time of 0.5 h to obtain positive electrode black powder.

[0052] The recovery methods of the positive electrode black powder in Examples 2 to 8 are basically the same as those in Example 1, except that the laser cleaning power is different, as shown in Table 1 for details.

[0053] The recovery methods of the positive electrode black powder of Examples 9 to 16 are basically the same as that of Example 1, except that the laser cleaning wavelengths are different, as shown in Table 1 for details.

[0054] The recovery methods of the positive electrode black powder of Examples 17 to 24 are basically the same as that of Example 1, except that the laser cleaning time is different, as shown in Table 1 for details.

[0055] Comparative Example 1

[0056] The recovery method of the positive electrode black powder in Comparative Example 1 is basically the same as that in Example 1, except that the laser power is 2500 W, the laser wavelength is 248 nm, and the cleaning time is 7 h.

[0057] Comparative Example 2

[0058] The recovery method of the positive electrode black powder in Comparative Example 2 is basically the same as that in Example 1, except that the laser power is 3000 W, the laser wavelength is 2100 nm, and the cleaning time is 5 h.

[0059] The physical properties of the positive electrode black powder in Examples 1 to 24 and Comparative Examples 1 to 2 are shown in Table 1, where H (003) / H (200) 、F (003) 、F (200) It can be obtained from the XRD test spectrum. Taking Example 1 as an example, the test spectrum is shown in Figure 1 The test spectra of other embodiments and comparative examples are similar and are not listed one by one. The results are shown in Table 1 for details.

[0060] Test Case

[0061] A mixed solution of 1 M sulfuric acid and 0.5 M hydrogen peroxide was used as an immersion agent. The recovered positive electrode black powder was chemically leached at 60°C, a solid-liquid ratio of 100 g / L, a stirring speed of 1000 rpm, and a reaction time of 30 min. The leaching efficiencies of lithium, nickel, cobalt, and manganese are shown in Table 2.

[0062] Table 1

[0063]

[0064] Table 1 (continued)

[0065]

[0066]

[0067]

[0068] Table 2

[0069] serial number Li(wt%) Ni(wt%) Co(wt%) Mn (wt%) Example 1 92 83 82 81 Example 2 93 87 86 86 Example 3 94 88 87 97 Example 4 95 91 90 89 Example 5 99 99 99 99 Example 6 99 99 99 99 Example 7 99 99 99 99 Example 8 99 99 99 99 Example 9 85 75 76 75 Example 10 95 86 86 86 Embodiment 11 96 87 87 87 Example 12 97 90 91 89 Example 13 98 91 92 90 Embodiment 14 99 93 93 93 Embodiment 15 99 95 95 95 Example 16 99 99 99 99 Embodiment 17 93 83 83 83 Embodiment 18 94 85 84 85 Embodiment 19 95 86 86 86 Embodiment 20 96 87 87 87 Embodiment 21 97 88 88 88 Embodiment 22 98 90 90 90 Embodiment 23 99 95 95 95 Embodiment 24 99 99 99 99 Comparative Example 1 78 55 56 55 Comparative Example 2 80 60 61 59

[0070] From the above embodiments and comparative examples, the present application improves the efficiency of wet recovery of leached lithium by controlling the ratio of the peak intensity of the 003 characteristic diffraction peak to the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder within a certain range, which is beneficial to simplify the subsequent recovery process and reduce the recovery cost.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A positive electrode black powder, characterized in that: The positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

2. The positive electrode black powder according to claim 1, characterized in that: The positive electrode black powder satisfies: 0.05°≤F (003) ≤0.2°, where F (003) It is the half-peak width of the 003 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder.

3. The positive electrode black powder according to claim 1, characterized in that: The positive electrode black powder satisfies: 0.3°≤F (200) ≤1°, where F (200) It is the half-peak width of the 200 characteristic diffraction peak in the X-ray diffraction pattern of the positive electrode black powder.

4. The positive electrode black powder according to claim 1, characterized in that: There are at least two characteristic peaks in the particle size distribution diagram of the positive electrode black powder, and at least one characteristic peak exists above 20 μm.

5. The positive electrode black powder according to claim 4, characterized in that: The volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the positive electrode black powder max Satisfy: 1≤H max ≤5.

6. The positive electrode black powder according to claim 1, characterized in that: The positive electrode black powder contains impurity elements, and the impurity elements include at least one of Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, Zr, Ti, La, Nb, Mo, and V. The total content C of the impurity elements satisfies: C≤3wt%.

7. The positive electrode black powder according to claim 1, characterized in that: The specific surface area B of the positive electrode black powder satisfies: 1m 2 / g≤B≤10m 2 / g.

8. The positive electrode black powder according to claim 1, characterized in that: The powder resistivity R of the positive electrode black powder 20KN satisfies: 50Ω*cm≤R≤300Ω*cm.

9. The positive electrode black powder according to claim 1, characterized in that: The positive electrode black powder 30KN powder compaction density D meets: 2.5g / cm 3 ≤D≤4g / cm 3 .

10. A method for recovering positive electrode black powder, characterized in that: The steps include: S1. Discharging the retired lithium-ion battery and disassembling it to obtain the positive electrode sheet; S2. Place the positive electrode sheet into a laser cleaning machine, and clean each surface of the positive electrode sheet for 0.5h to 4h at a laser wavelength of 337nm to 1064nm and a cleaning power of 100W to 2000W, and then sieve to obtain positive electrode black powder; The positive electrode black powder comprises a ternary material having a layered structure, and the positive electrode black powder satisfies: H (003) / H (200) ≥2, where H (003) is the peak intensity of the 003 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder, H (200) It is the peak intensity of the 200 characteristic diffraction peak in the X-ray diffraction spectrum of the positive electrode black powder.

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