ALUMINUM-DOPED NEEDLE-LIKE COBALTOSIC OXIDE AND PREPARATION METHOD THEREFOR

Abstract

The present application belongs to the technical field of battery materials, and discloses an aluminum-doped needle-like cobaltosic oxide and a preparation method therefor. The preparation method comprises the following steps: mixing a waste battery powder and an amino acid, adjusting the pH until an alkaline state is reached, and subjecting same to solid-liquid separation to obtain an aluminum-removed battery powder and a first filtrate; adding an acid to the aluminum-removed battery powder, mixing same, and subjecting same to solid-liquid separation to obtain a cobalt-containing acid solution and a copper-containing slag; adding, in a dropwise manner, a templating agent to the cobalt-containing acid solution, then adding an alkali to adjust the pH, centrifuging same, and subjecting same to a heat treatment to obtain an aluminum-doped needle-like cobaltosic oxide.

Claims

1. A method for preparing aluminium-doped needlelike tricobalt tetroxide, comprising the following steps: (1) mixing waste battery powder with an amino acid solution, adjusting pH to alkalinity, and performing solid-liquid separation, to obtain aluminum-removed battery powder and a first filtrate; (2) mixing the aluminum-removed battery powder with an acid solution, and performing solid-liquid separation, to obtain a cobalt-containing acid solution and a copper-containing slag; and (3) adding a template agent into the cobalt-containing acid solution dropwise, adjusting pH with an alkali, performing centrifugation and thermal treatment, to obtain the aluminium-doped needlelike tricobalt tetroxide.

2. The method according to claim 1, wherein in step (1), the waste battery powder is prepared by disassembling a waste lithium cobaltate traction battery pack into cells, discharging the cells, performing thermal decomposition on the cells in a rotary kiln, cooling, shredding, and screening.

3. The method according to claim 1, wherein in step (1), the amino acid solution is a solution of aminoacetic acid which has a concentration of 5 wt %-20 wt %; and the solid-liquid ratio of the waste battery powder to the amino acid solution is 10-60 g/L.

4. The method according to claim 1, wherein in step (1) and in step (3), the alkali used in the pH adjustment is one of lithium hydroxide, sodium hydroxide and potassium hydroxide.

5. The method according to claim 1, wherein in step (3), the template agent is added into the cobalt-containing acid solution dropwise in a molar quantity 1-5 times that of cobalt in the cobalt-containing acid solution.

6. The method according to claim 1, in step (3), further comprising: adding the first filtrate obtained in step (1) at an amount of 0.001-0.01 of the volume of the cobalt-containing acid solution during adding the template agent into the cobalt-containing acid solution dropwise.

7. The method according to claim 1, wherein in step (3), the template agent is one of aminosalicylic acid and hydroxyl-containing benzoic acid.

8. The method according to claim 1, wherein in step (3), the thermal treatment is carried out at a temperature of 550-750? C. for a duration of 1-6 h under an atmosphere of air.

9. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 1, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

10. Use of the aluminium-doped needlelike tricobalt tetroxide according to claim 9 in the preparation of a catalyst, a cathode material or a capacitor.

11. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 2, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

12. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 3, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

13. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 4, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

14. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 5, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

15. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 6, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

16. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 7, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

17. Aluminium-doped needlelike tricobalt tetroxide, prepared by the method according to claim 8, which has a chemical formula of Co.sub.3O.sub.4@C/Al.sub.2O.sub.3 and a specific surface area of 3.4-3.6 m.sup.2/g.

18. Use of the aluminium-doped needlelike tricobalt tetroxide according to claim 11 in the preparation of a catalyst, a cathode material or a capacitor.

19. Use of the aluminium-doped needlelike tricobalt tetroxide according to claim 12 in the preparation of a catalyst, a cathode material or a capacitor.

20. Use of the aluminium-doped needlelike tricobalt tetroxide according to claim 13 in the preparation of a catalyst, a cathode material or a capacitor.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0038] FIG. 1 is an SEM image of the needlelike tricobalt tetroxide prepared in Example 1 of the present disclosure; and

[0039] FIG. 2 is a TEM image of the needlelike tricobalt tetroxide prepared in Example 1 of the present disclosure.

DETAILED DESCRIPTION

[0040] The concept and the produced technical effects of the present disclosure will be clearly and completely described below with reference to the examples, so that the objective, characteristics and effects of the present disclosure can be fully understood. Apparently, the described examples are only a part of the examples of the present disclosure, rather than all of them. All the other examples, which is based on these examples of this disclosure, obtained by a person of ordinary skill in the art without creative labor should fall within the protection scope of the present invention.

EXAMPLES

Example 1

[0041] This example provided a method for preparing aluminium-doped needlelike tricobalt tetroxide comprising the following steps.

[0042] (1) A waste lithium cobaltate traction battery pack was disassembled into cells. The cells were resistance-discharged on a metal frame until single cell voltage <2.0 V, and then subjected to thermal decomposition in a rotary kiln at 400? C. for 6 h under nitrogen gas. The resulting product was cooled, shredded, and screened to remove the copper and aluminum foil as well as the separator, to obtain waste battery powder.

[0043] (2) The waste battery powder and 15.3 wt % of aminoacetic acid solution were mixed at an solid-liquid ratio of 15 g/L. The resulting solution was added with lithium hydroxide to adjust its pH to 10.3, and subjected to solid-liquid separation to obtain aluminum-removed battery powder and a first filtrate.

[0044] (3) The aluminum-removed battery powder was mixed with 0.0147 mol/L of sulfuric acid having a temperature <10? C. (at a solid-liquid ratio of 35 g/L), and subjected to solid-liquid separation, to obtain a cobalt-containing acid solution and a copper-containing slag.

[0045] (4) The cobalt content in the cobalt-containing acid solution was determined as 3.47 g/L. 150 mL of the cobalt-containing acid solution was diluted with water until its cobalt concentration was 0.029 g/L. Then, aminosalicylic acid was added dropwise to the cobalt-containing acid solution until the concentration was 0.057 mol/L, and also 0.3 mL of the first filtrate (having an aluminum content of 0.23 g/L) was added. The cobalt-containing acid solution was added with lithium hydroxide to adjust its pH to 6.8, stood for about 1.5 h, centrifuged, and washed to obtain a third solid Co(OH)(C.sub.7H.sub.6NO.sub.3).

[0046] (5) The third solid Co(OH)(C.sub.7H.sub.6NO.sub.3) was heated to 565? C. by a heating device, and kept for about 3 h, to obtain the aluminium-doped needlelike tricobalt tetroxide (Co.sub.3O.sub.4@C/Al.sub.2O.sub.3).

[0047] FIG. 1 was an SEM image of the needlelike tricobalt tetroxide prepared in Example 1 of the present disclosure. FIG. 2 was a TEM image of the needlelike tricobalt tetroxide prepared in Example 1 of the present disclosure. As can be seen from FIGS. 1-2, the prepared aluminium-doped needlelike tricobalt tetroxide (Co.sub.3O.sub.4@C/Al.sub.2O.sub.3) was long needle-like, had a diameter of about 0.3 ?m and showed uniform morphology and good dispersion.

Example 2

[0048] This example provided a method for preparing aluminium-doped needlelike tricobalt tetroxide comprising the following steps.

[0049] (1) A waste lithium cobaltate traction battery pack was disassembled into cells. The cells were resistance-discharged on a metal frame until single cell voltage <2.0 V, and then subjected to thermal decomposition in a rotary kiln at 400? C. for 6 h under nitrogen gas. The resulting product was cooled, shredded, and screened to remove the copper and aluminum foil as well as the separator, to obtain waste battery powder.

[0050] (2) The waste battery powder and 15.3 wt % of aminoacetic acid solution were mixed at a solid-liquid ratio of 18 g/L. The resulting solution was added with lithium hydroxide to adjust its pH to 10.1, and subjected to solid-liquid separation to obtain aluminum-removed battery powder and a first filtrate.

[0051] (3) The aluminum-removed battery powder was mixed with 0.0147 mol/L of sulfuric acid having a temperature <10? C. (at a solid-liquid ratio of 42 g/L), and subjected to solid-liquid separation, to obtain a cobalt-containing acid solution and a copper-containing slag.

[0052] (4) The cobalt content in the cobalt-containing acid solution was determined as 4.22 g/L, 150 mL of the cobalt-containing acid solution was diluted with water until its cobalt concentration was 0.034 g/L, Then, aminosalicylic acid was added dropwise to the cobalt-containing acid solution until the concentration was 0.063 mol/L, and 0.5 mL of the first filtrate (having an aluminum content of 0.25 g/L) was added. The cobalt-containing acid solution was added with lithium hydroxide to adjust its pH to 6.3, stood for about 1.5 h, centrifuged, and washed to obtain a third solid Co(OH)(C.sub.7H.sub.6NO.sub.3).

[0053] (5) The third solid Co(OH)(C.sub.7H.sub.6NO.sub.3) was heated to 615? C. by a heating device, and kept for about 3 h, to obtain the aluminium-doped needlelike tricobalt tetroxide (Co.sub.3O.sub.4@C/Al.sub.2O.sub.3).

Example 3

[0054] This example provided a method for preparing aluminium-doped needlelike tricobalt tetroxide comprising the following steps.

[0055] (1) A waste lithium cobaltate traction battery pack was disassembled into cells. The cells were resistance-discharged on a metal frame until single cell voltage <2.0 V, and then subjected to thermal decomposition in a rotary kiln at 400? C. for 6 h under nitrogen gas. The resulting product was cooled, shredded, and screened to remove the copper and aluminum foil as well as the separator, to obtain waste battery powder.

[0056] (2) The waste battery powder and 12.5 wt % of aminoacetic acid solution were mixed at a solid-liquid ratio of 34 g/L. The resulting solution was added with lithium hydroxide to adjust its pH to 10.2, and subjected to solid-liquid separation to obtain aluminum-removed battery powder and a first filtrate.

[0057] (3) The aluminum-removed battery powder was mixed with 0.0147 mol/L of sulfuric acid having a temperature <10? C. (at a solid-liquid ratio of 66 g/L), and subjected to solid-liquid separation, to obtain a cobalt-containing acid solution and a copper-containing slag.

[0058] (4) The cobalt content in the cobalt-containing acid solution was determined as 6.49 g/L. 150 mL of the cobalt-containing acid solution was diluted with water until its cobalt concentration was 0.027 g/L. Then, aminosalicylic acid was added dropwise to the cobalt-containing acid solution until the concentration was 0.077 mol/L, and 0.5 mL of the first filtrate (having an aluminum content of 0.27 g/L) was added. The cobalt-containing acid solution was added with lithium hydroxide to adjust its pH to 7.0, stood for about 1.5 h, centrifuged, and washed to obtain a third solid Co(OH)(C.sub.7H.sub.6NO.sub.3).

[0059] (5) The third solid Co(OH)(C.sub.7H.sub.6NO.sub.3) was heated to 565? C. by a heating device, and kept for about 3 h, to obtain the aluminium-doped needlelike tricobalt tetroxide (Co.sub.3O.sub.4@C/Al.sub.2O.sub.3).

Example 4

[0060] The method for preparing aluminium-doped needlelike tricobalt tetroxide of this example comprised the following steps.

[0061] (1) A waste lithium cobaltate traction battery pack was disassembled into cells. The cells were resistance-discharged on a metal frame until single cell voltage <2.0 V, and then subjected to thermal decomposition in a rotary kiln at 400? C. for 6 h under nitrogen gas. The resulting product was cooled, shredded, and screened to remove the copper and aluminum foil as well as the separator, to obtain waste battery powder.

[0062] (2) The waste battery powder and 12.5 wt % of aminoacetic acid solution were mixed at a solid-liquid ratio of 34 g/L. The resulting solution was added with lithium hydroxide to adjust its pH to 10.3, and subjected to solid-liquid separation to obtain aluminum-removed battery powder and a first filtrate.

[0063] (3) The aluminum-removed battery powder was mixed with 0.0147 mol/L of sulfuric acid having a temperature <10? C. (at a solid-liquid ratio of 66 g/L), and subjected to solid-liquid separation, to obtain a cobalt-containing acid solution and a copper-containing slag.

[0064] (4) The cobalt content in the cobalt-containing acid solution was determined as 6.49 g/L. 150 mL of the cobalt-containing acid solution was diluted with water until its cobalt concentration was 0.027 g/L. Then, aminosalicylic acid was added dropwise to the cobalt-containing acid solution until the concentration was 0.077 mol/L, and 0.5 mL of the first filtrate (having an aluminum content of 0.27 g/L) was added. The cobalt-containing acid solution was added with lithium hydroxide to adjust its pH to 7.0, stood for about 1.5 h, centrifuged, and washed to obtain a third solid Co(OH)(C.sub.7H.sub.6NO.sub.3).

[0065] (5) The third solid Co(OH)(C.sub.7H.sub.6NO.sub.3) was heated to 565? C. by a heating device, and kept for about 3 h. to obtain the aluminium-doped needlelike tricobalt tetroxide (Co.sub.3O.sub.4@C/Al.sub.2O.sub.3).

Analysis of Example 1-4:

[0066]

TABLE-US-00001 TABLE 1 The ratio of the aluminum contained in each sample to the total aluminum in Examples 1-4 impurity- first filtrate copper- cobalt- containing (aluminum containing containing items battery powder recovery rate) slag acid solution Example 1 7.1% 85.7% 1.3% 6.0% Example 2 5.0% 89.8% 1.9% 3.2% Example 3 2.8% 94.5% 0.6% 2.1% Example 4 3.9% 92.3% 0.9% 2.8%

TABLE-US-00002 TABLE 2 The ratio of the cobalt contained in each sample to the total cobalt in Examples 1-4 impurity- copper- cobalt- containing first containing containing items battery powder filtrate slag acid solution Example 1 91.9% 1.5% 6.1% 0.5% Example 2 92.7% 2.8% 3.8% 0.7% Example 3 94.9% 2.5% 2.4% 0.2% Example 4 93.8% 0.3% 3.6% 0.4%

TABLE-US-00003 TABLE 3 Specific surface area and particle size of the aluminium-doped needlelike tricobalt tetroxide prepared in Examples 1-4 items specific surface area (m.sup.2/g) D.sub.max (?m) D.sub.min (?m) Example 1 3.47 15.6 0.14 Example 2 3.53 15.3 0.13 Example 3 3.45 16.1 0.15 Example 4 3.41 15.9 0.14

[0067] As can be seen from tables 1-3, in Examples 1-4, the aluminum contained in the first filtrate accounted for 85.7%, 89.8%, 94.5% and 92.3% of the total aluminum (the total aluminum was the sum of aluminum in the impurity-containing battery powder, the first filtrate, the copper-containing slag and the cobalt-containing acid solution); the aluminum contained in the impurity-containing battery powder accounted for 7.1%, 5.0%, 2.8% and 3.9% of the total aluminum, while the cobalt contained in the impurity-containing battery powder accounted for 91.9%, 92.7%, 94.9% and 93.8% of the total cobalt. It was showed that the use of aminoacetic acid in combination of the addition of alkali was effective in selectively removing aluminum, as most of aluminum in the impurity-containing battery powder was removed while cobalt was retained in the copper-containing slag, and aluminum was effectively recovered in a green way. In addition, as shown in Table 3, the aluminium-doped needlelike tricobalt tetroxide prepared in Examples 1?4 showed relatively closed data in terms of their specific surface area, D.sub.max and D.sub.min, indicating that their morphologies are highly consistent.

[0068] The examples of the present disclosure have been described above in detail in conjunction with the drawings, but this invention is not limited thereto. Their variations can be made by those of ordinary skill in the art within the scope of their knowledge and without departing from the spirit of the present invention. In addition, the features of these examples can be combined with each other in the case of no conflict.