Regenerated ternary positive electrode material and preparation method and application thereof

Abstract

The invention provides a regenerated ternary positive electrode material as well as a preparation method and application thereof, and relates to the technical field of lithium ion battery ternary positive electrode materials. The invention relates to a preparation method of a regenerated ternary positive electrode material. The preparation method comprises the following steps: S1, roasting separation: roasting a waste ternary positive electrode plate, separating, crushing and sieving to obtain a waste ternary positive electrode material; s2, oxidation lithium removal: fully stirring the waste ternary positive electrode material and an oxidant solution, filtering, washing, and drying to obtain an oxidation lithium-removed ternary positive electrode material; s3, hydrothermal regeneration: carrying out hydrothermal reaction on the ternary positive electrode material subjected to oxidation lithium removal and a lithium hydroxide solution, filtering, washing and drying to obtain a hydrothermal regenerated ternary positive electrode material; and S4, sintering regeneration: uniformly mixing the hydrothermal regenerated ternary positive electrode material with metal salt, sintering, washing and drying to obtain the regenerated ternary positive electrode material. The regenerated ternary positive electrode material provided by the invention has relatively high specific capacity and excellent cycle performance.

Description

Technical Field

[0001] The present invention relates to the technical field of ternary positive electrode materials for lithium ion batteries, and in particular to a regenerated ternary positive electrode material and a preparation method and application thereof. Background Art

[0002] Ternary materials are made of lithium, nickel, cobalt, and manganese. During the cycle, the positive electrode undergoes a series of electrochemical reactions that cause physical and chemical changes in the material. Over time, these cycles can lead to material degradation, reduced battery capacity, and reduced performance. The content of valuable metals such as nickel, cobalt, and manganese in the positive electrode materials of waste ternary lithium-ion batteries is very high, so it is necessary to recycle and reuse ternary positive electrode materials.

[0003] At present, commercial recycling of large lithium-ion batteries mostly uses hydrometallurgical processes, pyrometallurgical processes or a combination of the two to recover valuable metals separately. However, pyrometallurgical treatment has disadvantages such as high energy consumption, loss of valuable metals, and low recovery rate. The hydrometallurgical chemical process is cumbersome and the wastewater and waste generated by the chemical reaction also need to be further processed, which will cause harm to the environment. Therefore, it is urgent to develop a preparation method for recycled ternary positive electrode materials with good environmental protection and high utilization rate, which is of great significance for the resource utilization of ternary positive electrode materials. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a regenerated ternary positive electrode material and a preparation method and application thereof.

[0005] The present invention provides a method for preparing a regenerated ternary positive electrode material, comprising the following steps:

[0006] S1, roasting and separation: roasting, separating, crushing and sieving the waste ternary positive electrode sheets to obtain the waste ternary positive electrode materials;

[0007] S2, oxidation delithiation: the waste ternary cathode material and the oxidant solution are fully stirred, filtered, washed and dried to obtain the ternary cathode material delithiation by oxidation;

[0008] S3, hydrothermal regeneration: after hydrothermal reaction of the ternary cathode material de-lithiated by oxidation with a lithium hydroxide solution, filtering, washing and drying to obtain a hydrothermally regenerated ternary cathode material;

[0009] S4, sintering regeneration: the hydrothermally regenerated ternary positive electrode material is mixed evenly with the metal salt, and sintered, washed and dried to obtain the regenerated ternary positive electrode material.

[0010] The present invention regenerates waste ternary positive electrode sheets to obtain regenerated ternary positive electrode materials through a four-step method of roasting separation-oxidation delithiation-hydrothermal regeneration-sintering regeneration. The preparation method of the present invention is simple and easy to implement, has good environmental protection, can recycle waste ternary positive electrode sheets, greatly improves the value of waste ternary positive electrode sheets, and can especially recycle lithium ion batteries using a mixed positive electrode formula, with high recovery value.

[0011] Preferably, in S1, the calcination comprises heating the material to 400-1000° C. at a heating rate of 5-10° C. / min and calcining the material for 3-10 hours.

[0012] Controlling the heating rate, temperature and time of calcination can help achieve a more complete reaction.

[0013] Preferably, in said S1, the mesh number of the sieving is greater than 200 meshes.

[0014] Preferably, in the S1, the chemical formula of the ternary cathode material is Li a (Ni x Co y Mn 1-x-y )O2, where 1.0≤a≤1.15, 0.3≤x<0.9, 0.05≤y≤0.15, 1-xy>0.

[0015] Preferably, in S2, the oxidant is selected from one or more of persulfates and peroxides.

[0016] More preferably, the oxidant solution is a supersaturated solution.

[0017] Preferably, in S2, the solid-liquid ratio of the waste ternary material to the oxidant solution is 1:(10-100).

[0018] Preferably, in S3, the hydrothermal reaction comprises reacting at 200-300° C. for 2-10 h.

[0019] Controlling the temperature and time of the hydrothermal reaction within a certain range is helpful to the recovery of the layered structure of the ternary material.

[0020] Preferably, in S3, the lithium hydroxide solution is a saturated lithium hydroxide solution.

[0021] Preferably, in said S3, the solid-liquid ratio of the ternary material for lithium oxide removal to the lithium hydroxide solution is 1:(10-100).

[0022] Controlling the solid-liquid ratio of the lithium-deoxidized ternary positive electrode material to lithium hydroxide within a certain range is helpful to restore the layered structure.

[0023] Preferably, in said S4, the sintering comprises sintering at 600-1000° C. for 4-10 h in an oxygen atmosphere.

[0024] Controlling the sintering temperature and time within a certain range is conducive to the full reaction, and the obtained regenerated ternary positive electrode material has good performance.

[0025] Preferably, in said S4, the metal salt comprises a lithium salt.

[0026] Preferably, in S4, the metal salt may also include one or more of nickel salt, cobalt salt and manganese salt.

[0027] More preferably, the lithium salt is selected from one or more of lithium carbonate and lithium hydroxide.

[0028] Preferably, in S3 and S4, the washing solvent is deionized water at 80-100°C.

[0029] The purpose of using 80-100°C deionized water as the washing solvent is to make the surface residue more soluble and remove the residue.

[0030] The present invention also provides a regenerated ternary positive electrode material prepared by the above preparation method.

[0031] An application of the above-mentioned regenerated ternary positive electrode material or the regenerated ternary positive electrode material prepared by the above-mentioned preparation method in a lithium-ion battery.

[0032] The beneficial effects of the present invention are:

[0033] The ternary nickel-cobalt-manganese material recycling method of the present invention is simple and easy to implement, has good environmental protection, can recycle the recovered positive electrode material, greatly improves the value of the recovered positive electrode material, and can especially recycle lithium-ion batteries using a mixed positive electrode formula, with high recycling value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the SEM image of the waste ternary positive electrode sheet proposed in Example 1 of the present invention.

[0035] Figure 2 This is the SEM image of the regenerated ternary positive electrode material proposed in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is described in detail through specific embodiments.

[0037] Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources.

[0038] Example 1

[0039] A method for preparing a regenerated ternary positive electrode material comprises the following steps:

[0040] S1, calcination separation: the waste ternary positive electrode sheet is calcined at 500°C for 5h, separated and crushed, and passed through a 250-mesh sieve to obtain the waste ternary positive electrode material NCM111;

[0041] S2, oxidative delithiation: 10g of waste ternary positive electrode material NCM111 was stirred with 500ml of 0.5M potassium persulfate solution at 50°C for 3h, filtered, washed with deionized water, and dried at 80°C to obtain oxidative delithiation ternary positive electrode material;

[0042] S3, hydrothermal regeneration: 1g of the ternary cathode material after delithiation was mixed with 100mL of saturated lithium hydroxide solution in a 250ml Teflon-lined autoclave, and the mixture was hydrothermally reacted at 220°C for 4h, filtered, washed with deionized water at 90°C to remove the residual lithium hydroxide, and dried at 80°C to obtain the hydrothermally regenerated ternary cathode material;

[0043] S4. Sintering regeneration: Mix 10g of hydrothermally regenerated ternary positive electrode material with 5 mol% excess lithium carbonate, heat the temperature to 800℃ at a heating rate of 2℃ / min, sinter for 5h, wash and filter in deionized water at 90℃, and dry at 80℃ to obtain the regenerated ternary positive electrode material SY-cp-Ni33.

[0044] Example 2

[0045] The difference between Example 2 and Example 1 is that NiSO4·6H2O is additionally added to S4 to adjust the Ni content in the material to 50%, and the finished product is SY-cp-Ni50, and other conditions remain unchanged.

[0046] Example 3

[0047] The difference between Example 3 and Example 1 is that the waste ternary positive electrode material in S1 is NCM523 and NiSO4·6H2O is additionally added in S4 to adjust the Ni content in the material to 55%, and the finished product is SY-cp-Ni55, and other conditions remain unchanged.

[0048] Example 4

[0049] The only difference between Example 4 and Example 3 is that NiSO4·6H2O is added to S4 to adjust the Ni content in the material to 60%, and the finished product is SY-cp-Ni60, and other conditions remain unchanged.

[0050] Comparative Example 1

[0051] Waste ternary positive electrode material NCM111.

[0052] Comparative Example 2

[0053] Waste ternary positive electrode material NCM523.

[0054] The regenerated ternary positive electrode materials prepared in the above examples 1-4 and the waste ternary positive electrode materials in comparative examples 1-2 were subjected to battery assembly and button test. The specific method is: the positive electrode material, acetylene black, and polyvinylidene fluoride (PVDF) were weighed and mixed uniformly in a mass ratio of 90:5:5, and NMP was added for stirring to make a uniform slurry; then the slurry was evenly coated on aluminum foil, and a metal lithium sheet was used as the negative electrode sheet, 1 mol / L LiPF6 was used as the electrolyte, and a polypropylene microporous membrane was used as the diaphragm, and the button battery was assembled in a glove box filled with argon. The assembled button battery was subjected to constant current charge and discharge test and low temperature DCR test at room temperature, and the charge and discharge cut-off voltage was 2.8V-4.4V. The electrochemical performance test results are shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058] It can be seen from the data in Table 1 that the regenerated ternary cathode material prepared by the present invention has good charge and discharge performance. It can be seen from the data of the comparative example and the embodiment that the discharge capacity of NCM111 at 0.2C and 0.33C is increased by 32.8 and 30.6 mAh / g, respectively, and that of NCM523 is increased by 35.3 and 35.6 mAh / g, respectively. The capacity retention rate of the regenerated ternary cathode material after 50 cycles is about 90%, indicating that the regenerated material has good performance and great value.

[0059] like Figure 1 As shown, Figure 1 This is a SEM image of the waste ternary positive electrode sheet proposed in Example 1 of the present invention; Figure 2 This is a SEM image of the regenerated ternary cathode material proposed in Example 1 of the present invention. Figure 1 and Figure 2 It can be seen from the comparison that the ternary material has obvious cracks after long-term cycling, while the cracks in the regenerated particles disappear and the particles are intact.

[0060] In summary, the regenerated ternary positive electrode material provided by the present invention has a high specific capacity and excellent cycle performance.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a regenerated ternary positive electrode material, characterized in that: The following steps are involved: S1, roasting and separation: roasting, separating, crushing and sieving the waste ternary positive electrode sheets to obtain the waste ternary positive electrode materials; S2, oxidation delithiation: the waste ternary cathode material and the oxidant solution are fully stirred, filtered, washed and dried to obtain the ternary cathode material delithiation by oxidation; S3, hydrothermal regeneration: after hydrothermal reaction of the ternary cathode material de-lithiated by oxidation with a lithium hydroxide solution, filtering, washing and drying to obtain a hydrothermally regenerated ternary cathode material; S4, sintering regeneration: the hydrothermally regenerated ternary positive electrode material is mixed evenly with the metal salt, and sintered, washed and dried to obtain the regenerated ternary positive electrode material.

2. The preparation method according to claim 1, characterized in that: In the above S1, the calcination includes heating the material to 400-1000° C. at a heating rate of 5-10° C. / min and calcining the material for 3-10 hours.

3. The preparation method according to claim 1, characterized in that: In the S2, the oxidant is selected from one or more of persulfate and peroxide.

4. The preparation method according to claim 1, characterized in that: In the above-mentioned S3, the hydrothermal reaction comprises reacting at 200-300° C. for 2-10 hours.

5. The preparation method according to claim 1, characterized in that: In the S3, the solid-liquid ratio of the ternary material for delithiation of lithium and the lithium hydroxide solution is 1:(10-100).

6. The preparation method according to claim 1, characterized in that: In the above-mentioned S4, the sintering includes sintering at 600-1000° C. for 4-10 hours in an oxygen atmosphere.

7. A regenerated ternary positive electrode material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the regenerated ternary positive electrode material according to any one of claim 7 or the regenerated ternary positive electrode material prepared by the preparation method according to any one of claims 1 to 6 in a lithium-ion battery.

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