Oxalic acid chemical activation regeneration method of waste lithium battery ternary positive electrode material

Abstract

The invention discloses an oxalic acid chemical activation regeneration method of a waste lithium battery ternary positive electrode material, and belongs to the technical field of resource regeneration. The method comprises the following steps: collecting the positive electrode material by a physical method, carrying out acid leaching and lithium extraction on the recycled positive electrode material by oxalic acid and ethylene glycol double coordination, supplementing metal oxalate, a lithium source and oxalic acid, carrying out mixing, ball milling and chemical damage, and carrying out high-temperature solid-phase method regeneration on the mixed material to obtain the ternary positive electrode material. The basic structure of the material collected on the basis of a physical method is seriously damaged besides impurity elements such as C and F on the surface, and the method is characterized in that the waste ternary positive electrode material is subjected to solid-phase regeneration through combined use of oxalic acid lithium leaching and oxalic acid ball-milling chemical damage methods, and the method is short in process, low in cost and high in efficiency. The efficiency is high, and the purpose of resource recycling is achieved. The electrochemical performance of the regenerated positive electrode material can be close to that of a commercial material.

Description

Technical Field

[0001] The invention discloses an oxalic acid chemical activation and regeneration method for waste lithium battery ternary positive electrode materials, belonging to the technical field of resource regeneration. Background Art

[0002] In recent years, lithium-ion batteries have been widely used not only in portable electronic devices, but also in large energy storage fields such as power vehicles, due to their advantages such as high power, high energy density, environmental friendliness, long cycle life, and no memory effect. Although lithium-ion batteries have a long life, as their applications become more and more extensive, especially in power vehicles, the number of batteries used is huge, and the life span is usually 5-10 years. The number of waste batteries will increase accordingly. Waste lithium-ion batteries not only pollute the environment, but also cause waste of valuable metals and other materials in the positive electrode materials. Therefore, the recycling of power lithium batteries has high practical value.

[0003] At present, the recycling of used power batteries is still in its early stages. The existing recycling industrialization is small-scale, inefficient, and highly polluting, and cannot meet the urgent needs of a large number of used power batteries. To achieve large-scale industrialization of used power battery recycling, direct regeneration is obviously the most suitable method. At present, we are exploring a process with low recycling cost, green environmental protection, simple process, and high recovery rate. Summary of the invention

[0004] The purpose of the present invention is to design a method for regenerating waste nickel-cobalt-manganese ternary positive electrode materials, aiming to regenerate the recycled ternary positive electrode materials on the basis of reducing costs, and obtain a ternary nickel-cobalt-manganese positive electrode material with excellent electrochemical properties and good structural crystal form.

[0005] The method proposed by the present invention is applicable to ternary nickel-cobalt-manganese positive electrode materials in various proportions.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for regenerating ternary positive electrode materials of waste lithium batteries, characterized in that it comprises the following steps:

[0008] (1) Peeling off the positive electrode material from the current collector;

[0009] (2) placing the stripped material obtained in step (1) in deionized water, ultrasonicating, filtering, and drying to obtain a positive electrode material collected by a physical method;

[0010] (3) calcining the collected positive electrode material at 800°C for 2h in an air atmosphere to obtain a pretreated positive electrode material. The pretreated recycled material effectively removes impurity elements such as C and F to avoid affecting the performance of the regenerated material;

[0011] (4) adding the positive electrode material collected in step (3) to a solution of oxalic acid and ethylene glycol;

[0012] (5) using an external mechanical stirring device to heat and stir, and then filtering;

[0013] (6) ball milling the leached residue with nickel, cobalt and manganese oxalate and oxalic acid, specifically:

[0014] According to the metal element determination results, the molar ratio of nickel: cobalt: manganese: lithium in the material is supplemented to (0.5-0.51): (0.2-0.21): (0.3-0.31): (1-1.05). If the molar content of nickel, cobalt, manganese and lithium in the material is within the above range, the corresponding metal oxides are not added;

[0015] (7) calcining the ball-milled mixed material at 850° C. for 12 h to obtain a regenerated ternary positive electrode material;

[0016] In step (2) of the present invention, the ultrasonic time is 0.5h and the drying temperature is 80°C.

[0017] In step (4) of the present invention, the molar ratio of ethylene glycol to oxalic acid is 7:1, and the solid-liquid ratio of the positive electrode material to the mixed solution is 8 g / L.

[0018] In step (5) of the present invention, the stirring speed is 900 rpm, the stirring time is 30 min, and the heating temperature is 90° C.

[0019] The ball milling parameters in step (6) of the present invention are 500 r / min, 6 h.

[0020] The present invention takes into account that the main causes of failure of the positive electrode material are lithium loss and destruction of the positive electrode layered structure. The method uses a double coordination acid leaching method of ethylene glycol and oxalic acid for lithium extraction, which has a good lithium extraction effect, is beneficial to the recovery of the layered structure in the subsequent regeneration process, and the electrochemical performance of the regenerated material is good. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is the SEM image of the leached residue obtained by leaching lithium with oxalic acid and ethylene glycol; Figure 2 This is the XRD diagram of the leached residue obtained by leaching lithium with oxalic acid and ethylene glycol; Figure 3 The first cycle charge and discharge curves of the products of different calcination temperatures in this regeneration method; Figure 4 This is the long cycle performance diagram of the products of different calcination temperatures in this regeneration method; Figure 5 This is the rate performance diagram of the products of different calcination temperatures in this regeneration method. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention will be described in detail below, but it should be pointed out that for those skilled in the art, without departing from the principles of the present invention, the modifications made are not within the scope of this specific embodiment, but are also included in the protection scope of the present invention.

[0023] (1) Separating the positive electrode sheets from the current collectors collected from the waste batteries and collecting the materials;

[0024] (2) placing the collected material in deionized water and ultrasonicating it for half an hour, filtering it, and then placing it in an 80°C forced air oven and drying it for 6 hours to obtain the positive electrode material collected by the physical method;

[0025] (3) calcining the collected positive electrode material at 800°C for 2h in an air atmosphere to obtain a pretreated positive electrode material. The pretreated recycled material effectively removes impurity elements such as C and F to avoid affecting the performance of the regenerated material;

[0026] (4) preparing a solution of ethylene glycol and oxalic acid in a molar ratio of 7:1, and adding the collected positive electrode material to the solution, wherein the solid-liquid ratio of the positive electrode material to the mixed solution is 8 g / L;

[0027] (5) using an external mechanical stirring device to heat and stir, the stirring speed is 900 rpm, the stirring time is 30 min, the heating temperature is 90° C., and then filtering;

[0028] (6) ball milling the leached residue with nickel-cobalt-manganese oxalate, lithium carbonate and oxalic acid at a speed of 500 r / min for 6 h. According to the results of metal element determination, nickel-cobalt-manganese oxalate and lithium carbonate were added to make the molar ratio of the metal elements nickel:cobalt:manganese:lithium in the material 0.5:0.2:0.3:1.05;

[0029] (7) calcining the ball-milled mixed material at 850° C. for 12 h in an air atmosphere to obtain a regenerated ternary positive electrode material;

[0030] 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 modifications and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the ideas and principles of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for chemically activating and regenerating waste lithium battery ternary cathode materials with oxalic acid, characterized in that: The steps include: (1) Peeling off the positive electrode material from the current collector; (2) placing the stripped material obtained in step (1) in deionized water, ultrasonicating, filtering, and drying to obtain a positive electrode material collected by a physical method; (3) calcining the collected positive electrode material at 800° C. for 2 h in an air atmosphere to obtain a pretreated positive electrode material, and removing C and F impurity elements from the pretreated recycled material; (4) adding oxalic acid and ethylene glycol to the positive electrode material collected in step (3) and mixing them evenly; the molar ratio of ethylene glycol to oxalic acid is 7:1, and the solid-liquid ratio of the mixed solution of the positive electrode material and ethylene glycol and oxalic acid is 8 g / L; (5) using an external mechanical stirring device to heat and stir at a temperature of 90° C., and then filtering; (6) ball milling the leached residue with nickel, cobalt and manganese oxalate and oxalic acid, specifically: According to the metal element determination results, the molar ratio of nickel: cobalt: manganese: lithium in the material is supplemented to (0.5-0.51): (0.2-0.21): (0.3-0.31): (1-1.05). If the molar content of nickel, cobalt, manganese and lithium in the material is within the above range, the corresponding metal oxides are not added; (7) The ball-milled mixed material was calcined at 850°C for 12 h to obtain a regenerated ternary positive electrode material.

2. The method according to claim 1, characterized in that: In the step (2), the ultrasonic time is 0.5 h and the drying temperature is 80° C.

3. The method according to claim 1, characterized in that: In the step (5), the stirring speed is 900 rpm and the stirring time is 30 min.

4. The method according to claim 1, characterized in that: The ball milling parameters in step (6) are 500 r / min, 6 h.

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