Pretreatment method of failure lithium ion battery positive electrode material

A positive electrode material and pretreatment technology, applied to battery electrodes, positive electrodes, secondary batteries, etc., can solve problems such as unsatisfactory lithium supplementation effects, achieve improved regeneration efficiency and performance indicators, simple and efficient procedures, and good repeatability Effect

Pending Publication Date: 2020-07-03

武汉瑞杰特材料有限责任公司

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AI-Extracted Technical Summary

Problems solved by technology

This method is convenient and quick, but the effect of lithium supplementation is not ...

Abstract

The invention provides a pretreatment method of a failure lithium ion battery positive electrode. The pretreatment method comprises the following steps: S1, weighing a lithium salt, and adding water to prepare a lithium salt solution with a concentration of greater than or equal to 0.1 mol/L, wherein the lithium salt is an inorganic lithium salt; S2, testing the lithium deficiency ratio x of a failure positive electrode material, and mixing the lithium salt solution obtained in the S1 and the failure positive electrode material to obtain a mixture, wherein the molar ratio of the lithium in thelithium salt solution to the positive electrode material is greater than or equal to the lithium deficiency ratio x of the failure positive electrode material; S3, carrying out a hydrothermal reaction on the mixture obtained in the S2 in a high-pressure hydrothermal kettle, and monitoring the Li<+> concentration of the mixture in the kettle until the concentration is not continuously reduced so as to complete the reaction, wherein the hydrothermal reaction temperature is greater than or equal to 100 DEG C; and S4, cooling, filtering to remove the solvent, washing with water to remove the residual lithium salt, and drying to obtain the lithium-supplementing positive electrode material. The method provided by the invention can improve the regeneration efficiency and performance index of therecycled material, has good repeatability, high resource utilization rate and simple and efficient process, and has high social and economic values.

Application Domain

Electrolyte/reactants regenerationPositive electrodes +2

Technology Topic

Lithium electrodePretreatment method +7

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Examples

Experimental program(4)
Comparison scheme(1)

Example Embodiment

[0050] Example 1

[0051] A pretreatment method for the cathode material of a failed lithium ion battery includes the following steps:

[0052] S1 Weigh 7.66 g of LiOH into a beaker with an electronic balance, add 80 ml of distilled water with a pipette, and magnetically stir for 20 minutes to dissolve, and prepare a 4 mol/L lithium salt solution.

[0053] S2 uses ICP to test failed cathode material NCM523 (LiNi 0.5 Co 0.2 Mn 0.3 O 2 The ratio of Li/Me in) is 0.81 measured in this embodiment, and the ratio of lithium deficiency is 0.19. Weigh 25.0 g of the spent positive electrode material, add the lithium salt solution of S1, so that the molar ratio of lithium in the lithium salt solution to the spent positive electrode material is 3.5, which is 17 times the lithium deficiency ratio x, and magnetically stir for 10 minutes to obtain a mixture.

[0054] S3 transfers the mixture of S2 to a high-pressure hydrothermal kettle with tetrafluoroethylene lining, and reacts hydrothermally at a temperature of 200°C. During the process, a pH meter or acid-base titration is used to monitor the Li content of the mixture in the kettle. + When the concentration does not decrease, the hydrothermal reaction is completed, and the time is 8h.

[0055] S4 was cooled to 50°C, opened the high-pressure hydrothermal kettle, filtered with suction, washed with distilled water 3 times, and tested the pH of the filtrate with a precision pH test paper. In this example, the measured pH was 7.6, and the washing was sufficient.

[0056] Then, the washed material is placed in a blast drying box and dried at 130°C for 2 hours to obtain a lithium-supplemented cathode material.

[0057] ICP was used to test the Li/Me of the positive electrode material after lithium supplementation in this embodiment = 1.06. The Li/Me test results of the positive electrode material before and after lithium supplementation are as follows: figure 1 As shown, it can be seen that by using the method of this embodiment, the lithium element in the spent positive electrode material has been completely replenished.

[0058] The X-ray diffraction analysis of the positive electrode material before and after the lithium supplementation was obtained in this example, the results obtained are as follows figure 2 As shown, it can be seen that the crystal phase of the material has not changed, but the crystallinity is higher and the impurity phase is reduced.

Example Embodiment

[0059] Example 2

[0060] A pretreatment method for the cathode material of a failed lithium ion battery includes the following steps:

[0061] S1 Weigh 22.17g Li with an electronic balance 2 CO 3 In a beaker, add 60ml of distilled water with a pipette, magnetically stir for 10min to dissolve, and prepare a 5mol/L lithium salt solution.

[0062] S2 uses ICP to test failed cathode material LiCoO 2 The ratio of Li/Co in this embodiment is 0.60, and the ratio of lithium deficiency is 0.40. Weigh 56 g of the spent positive electrode material and add the S1 lithium salt solution to make the molar ratio of lithium in the lithium salt solution to the spent positive electrode material 3, which is 7.5 times the lithium deficiency ratio x, and magnetically stir for 10 minutes to obtain a mixture.

[0063] S3 transfers the mixture of S2 to a high-pressure hydrothermal kettle with tetrafluoroethylene lining, and reacts hydrothermally at 240℃. During the process, a pH meter or acid-base titration is used to monitor the Li content of the mixture in the kettle. + When the concentration no longer decreases, the hydrothermal reaction is completed and the time is 4h.

[0064] The temperature of S4 was lowered to 30°C, the high-pressure hydrothermal kettle was opened, filtered with suction, and washed with distilled water 3 times, and the pH of the filtrate was tested with a precision pH test paper. In this example, the measured pH=8.2, and the washing was sufficient.

[0065] Then the washed material is placed in a blast drying box and dried at 150°C for 1 hour to obtain a lithium-supplemented positive electrode material.

[0066] Using ICP to test this example, the Li/Co of the positive electrode material for lithium supplementation is Li/Co=0.99. The Li/Co test results of the positive electrode material before and after lithium supplementation are as follows: image 3 As shown, it can be seen that by using the method of this embodiment, the lithium element in the spent positive electrode material has been completely replenished.

Example Embodiment

[0067] Example 3

[0068] A pretreatment method for the cathode material of a failed lithium ion battery includes the following steps:

[0069] S1 Weigh 0.72g of LiOH into a beaker with an electronic balance, add 30ml of distilled water with a pipette, and magnetically stir for 10min to dissolve it to prepare a 1mol/L lithium salt solution;

[0070] S2 uses ICP to test failed cathode material LiFePO 4 The ratio of medium Li/Fe, measured in this embodiment, is 0.65, and the ratio of lithium deficiency is 0.35. Weigh 2.37 g of the spent positive electrode material, add the lithium salt solution of S1, so that the molar ratio of lithium in the lithium salt solution to the spent positive electrode material is 2, which is 5.7 times the lithium deficiency ratio x, and magnetically stir for 10 minutes to obtain a mixture.

[0071] S3 transfers the mixture of S2 to a high-pressure hydrothermal kettle with tetrafluoroethylene lining, and reacts hydrothermally at a temperature of 180°C. During the process, a pH meter or acid-base titration is used to monitor the Li content of the mixture in the kettle. + When the concentration does not decrease, the hydrothermal reaction is completed, and the time is 6h;

[0072] The temperature of S4 was lowered to 50°C, the high-temperature and high-pressure hydrothermal kettle was opened, filtered with suction, washed with distilled water 3 times, and the pH of the filtrate was tested with a precision pH test paper. In this example, the measured pH was 7.2, and the washing was sufficient.

[0073] Then the washed material is placed in a blast drying box and dried at 200° C. for 0.5 h to obtain a lithium-supplemented cathode material.

[0074] The lithium-supplemented positive electrode material was Li/Fe=1.03 by ICP testing in this embodiment. Further, the cathode material is made into a button battery, and the performance test is performed. The test result is as follows Figure 4 As shown, the material capacity has returned to a normal level, which verifies that the method of this embodiment is sufficient for replenishing lithium.

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Classification and recommendation of technical efficacy words

good repeatability

Pretreatment method of failure lithium ion battery positive electrode material

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

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Description & Claims & Application Information

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