Total leaching and regeneration method of positive electrode active material of waste lithium ion battery

Abstract

The invention belongs to the field of battery material recovery, and particularly relates to a total leaching method of a waste lithium ion battery positive electrode active material, which comprises the following steps: mixing a waste positive electrode material separated from a waste lithium ion battery with an aqueous solution containing a leaching agent with a formula 1 # imgabs0 #, leaching, and carrying out solid-liquid separation to obtain a leaching solution enriched with metal ions in a material to be treated. Researches show that the compound in the formula 1 is combined with the concentration and the temperature, so that crystals and physical and chemical structures of the compound can be quickly misunderstood without assistance of other leaching aids, and efficient and mild total metal leaching of the positive electrode material can be realized. In addition, according to the leaching method, leaching impure phases cannot be introduced, the physical and chemical performance of the regenerated material can be accidentally optimized, and the regenerated material with excellent performance can be obtained through regeneration.

Description

Technical Field

[0001] The invention belongs to the field of battery waste recycling, and specifically relates to the field of waste lithium battery material recycling. Background Art

[0002] In recent years, the global demand for electric vehicles (EVs) has continued to grow, and concerns about carbon emissions have also prompted the rapid development of the EV battery industry. As a result, the shipments of lithium batteries (LIBs) have increased year by year, but the service life of such batteries is usually only 3-5 years. Due to the growth in power battery production in the past five years, the amount of scrapped batteries has also increased rapidly. Generally speaking, waste lithium batteries contain a variety of valuable metals such as cobalt, copper, lithium, nickel, and manganese, as well as harmful substances such as organic electrolytes and positive electrode waste carbon, which will not only pollute water sources and soil, but also pose a great threat to human health. At the same time, lithium, cobalt and nickel are high-value metals in waste lithium batteries. Therefore, the recycling of waste lithium batteries is of great significance both economically and environmentally.

[0003] The existing recycling methods for the positive electrode materials of waste lithium-ion batteries mainly rely on water leaching, acid leaching, etc. For example, the Chinese patent document CN118561254A discloses a method for recovering lithium salts from waste lithium-ion batteries and preparing lithium iron manganese phosphate positive electrode materials, which specifically records the scheme of using oxalic acid or persulfate as a leaching agent for leaching. This method can only achieve pre-extraction of lithium, but cannot achieve simultaneous and efficient leaching of transition metals. In addition, the amount of leaching agent required is large, and the temperature conditions in the leaching stage are high.

[0004] For another example, the Chinese patent document with publication number CN118572236A discloses a positive electrode and a method for recovering a positive electrode of a potassium ion battery Prussian blue analog prepared from a retired power lithium battery positive electrode material, which specifically records a scheme of leaching using an acidic solvent, wherein the acidic reagent used is a solution containing a 1.0-10 vol% hydrogen peroxide solution and an organic acid such as acetic acid with a concentration of 1 to 4 mol / L. This scheme requires the use of a reducing agent for auxiliary acid leaching, and the required concentration of the leaching agent is relatively high.

[0005] In summary, the existing leaching process still has room for improvement in reducing the types of leached components, reducing leached impurities, and achieving efficient and mild leaching at low material dosage. Summary of the invention

[0006] In view of the problems faced by the existing recycling of positive electrodes of waste lithium-ion batteries, the purpose of the present invention is to provide a full leaching method for the positive electrode active materials of waste lithium-ion batteries, aiming to provide an efficient full leaching scheme with low material dosage without introducing leached impurities.

[0007] The second object of the present invention is to provide a method for regenerating positive electrode active materials of waste lithium-ion batteries, aiming to regenerate positive electrode materials with excellent electrochemical properties at a high recovery rate.

[0008] The structure of the waste positive electrode material is dense, and there is a dense SEI layer on its surface caused by circulation. In addition, its lattice is closely embedded, and it is difficult to effectively break through its physical and chemical structure by conventional acid leaching, and most of them need to rely on reducing components; this will increase the material cost, and it is also easy to introduce leaching impurities, which will increase the recovery process and steps of the leaching solution. In addition, it may also affect the electrochemical properties of the recycled material. In view of this problem, the present invention has been studied in depth and provides the following solution:

[0009] A method for fully leaching the positive electrode active material of waste lithium ion batteries, comprising mixing the waste positive electrode material separated from the waste lithium ion batteries with a 0.1-1M aqueous solution of formula 1, and performing a leaching treatment at a temperature of 40-100° C., followed by solid-liquid separation to obtain a leachate enriched with metal ions in the material to be treated;

[0010]

[0011] The R is a saturated carbon chain of C1 to C6.

[0012] The present invention shows that a single compound of formula 1 can effectively adapt to the physicochemical characteristics of the positive electrode material, and can quickly disintegrate its crystal and physicochemical structure at the concentration and temperature, so as to achieve efficient and gentle full leaching of the metal of the positive electrode material. In addition, the leaching method of the present invention not only does not introduce leaching impurities, but also unexpectedly optimizes the physicochemical properties of the regenerated material, which helps to regenerate a regenerated material with excellent performance.

[0013] In the present invention, the waste positive electrode material can be recovered based on conventional methods.

[0014] For example, the waste positive electrode material is obtained by stripping the positive electrode of waste lithium-ion batteries;

[0015] For example, the waste positive electrode material contains positive electrode active material; it is also allowed to contain at least one component of a current collector, a binder, a conductive agent, and an electrolyte.

[0016] For example, the positive electrode active material is a transition metal oxide containing lithium.

[0017] For example, the transition metal in the positive electrode active material includes at least one of nickel, cobalt, and manganese.

[0018] For example, the positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and nickel-cobalt-manganese ternary.

[0019] For example, the content of active material in the waste positive electrode material is above 50 wt.%, more preferably above 80 wt.%, and further preferably 80 to 95 wt.%.

[0020] In the present invention, in Formula 1, R is methylene, 1,2-ethylene, 1,3-propylene or 1,4-butylene.

[0021] In the present invention, thanks to the combination of the structure of Formula 1, it can unexpectedly adapt to the physical and chemical characteristics of the waste positive electrode, and it can achieve full leaching of metals gently and efficiently with low material consumption.

[0022] For example, the concentration of Formula 1 in the aqueous solution of the leaching agent of Formula 1 is 0.1 to 0.7 M, and further can be 0.4 to 0.5 M. The Formula 1 of the present invention can achieve gentle and efficient leaching of waste positive electrode materials at a low concentration.

[0023] In the present invention, the liquid-to-solid ratio in the leaching stage is 20 to 40 mL / g.

[0024] In the present invention, the temperature in the leaching stage is 45-85°C.

[0025] In the present invention, the leaching stage is carried out with the assistance of ultrasound, and the power of the ultrasound can be 100-500W.

[0026] In the present invention, the leaching time can be adjusted according to the leaching conditions, for example, it can be more than 0.5 h, preferably 1 to 4 h.

[0027] The present invention also provides a method for regenerating positive electrode active materials of waste lithium-ion batteries, which comprises the following steps: performing leaching treatment by the full leaching method of the present invention to obtain the leaching solution, performing coprecipitation treatment on the leaching solution, filtering to obtain a precursor and a lithium liquid, subjecting the lithium liquid to lithium precipitation treatment to obtain a lithium source, and calcining the precursor with lithium to obtain a regenerated positive electrode active material.

[0028] The coprecipitation and lithium calcination methods described in the present invention can be conventional.

[0029] The present invention also includes the regenerated positive electrode active material obtained by the regeneration method.

[0030] The present invention also includes the feature of preparing the required battery such as lithium ion battery based on the existing means and ideas by using the regenerated positive electrode active material.

[0031] Beneficial Effects

[0032] The present invention shows that the combination of the compound of formula 1 with the concentration and temperature can quickly precipitate its crystal and physicochemical structure without the aid of other leaching aids, and can achieve efficient and gentle full leaching of the metal of the positive electrode material. In addition, the leaching method of the present invention not only does not introduce leaching impurities, but also unexpectedly optimizes the physicochemical properties of the regenerated material, which helps to regenerate the regenerated material with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 XRD pattern of the material regenerated in Example 1;

[0034] Figure 2 This is the cycle diagram of the regenerated material of Example 1 at 1C and 25°C; DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0036] In the present invention, the positive electrode material of waste lithium-ion batteries can be obtained by disassembling the positive electrode of waste lithium-ion batteries and stripping the current collector (for example, the stripping method is NMP stripping method). There is no special requirement for the content of active materials therein. Considering the economic efficiency of the process, in the following cases, unless otherwise stated, the active content is 85 to 90 wt.%.

[0037] In addition, in order to further verify the metal regeneration advantage of the leaching solution obtained by the present invention, the present invention selects waste lithium-ion batteries with the same morphology for recycling and regeneration.

[0038] The following are typical solutions:

[0039] Example 1

[0040] Place the waste positive electrode material (obtained from stripping of waste NCM111 batteries) in 0.5M formula 1-A The leaching solution was prepared by leaching at 50 °C for 2 h in an aqueous solution (liquid-to-solid ratio of 20 mL / g) to obtain a leaching solution rich in Li, Ni, Co, and Mn.

[0041] The leaching rates of each valuable metal are Ni 99.4%, Co 99.5%, Mn 99.5%, and Li 99.8%.

[0042] Example 2

[0043] Compared with Example 1, the only difference is that the waste positive electrode material is replaced by the waste positive electrode obtained from the waste lithium cobalt oxide battery, and the other operations and parameters are the same as Example 1.

[0044] The leaching rates of each valuable metal are Co 99.5% and Li 99.6%.

[0045] Example 3

[0046] Compared with Example 1, the only difference is that the waste positive electrode material is replaced by the waste positive electrode obtained from the waste lithium nickel acid battery, and the other operations and parameters are the same as Example 1.

[0047] The leaching rates of each valuable metal are Mn 99.4% and Li 99.5%.

[0048] Example 4

[0049] Compared with Example 1, the only difference is that the leaching temperature is changed to 80°C, the concentration of Formula 1-A in the starting leaching aqueous solution is 0.4M, and the liquid-to-solid ratio is 30mL / g; the leaching time is 1h, and the other operations and parameters are the same as Example 1.

[0050] The leaching rates of each valuable metal are Ni 99.6%, Co 99.7%, Mn 99.7%, and Li 99.9%.

[0051] Example 5

[0052] Compared with Example 1, the only difference is that ultrasonic stirring is added, the power is 300 W, the leaching time is 0.5 h, and the other operations and parameters are the same as Example 1. The leaching rates of each valuable metal are Ni 99.8%, Co 99.8%, Mn 99.8%, and Li 99.9%.

[0053] Comparative Example 1

[0054] Compared with Example 1, the only difference is that the comparative formula b is used The other operations and parameters are the same as those in Example 1.

[0055] The leaching rates of each valuable metal are Ni 70.2%, Co 71.5%, Mn 73.4%, and Li 85.9%.

[0056] Comparative Example 2

[0057] Compared with Example 1, the only difference is that Formula 1-A is not added, and other operations and parameters are the same as Example 1.

[0058] The leaching rate of each valuable metal does not exceed 5%.

[0059] Comparative Example 3

[0060] Compared with Example 1, the only difference is that the leaching temperature is adjusted to 25° C., and other operations and parameters are the same as Example 1.

[0061] The leaching rates of each valuable metal are Ni 56.3%, Co 55.7%, Mn 52.8%, and Li 69.7%.

[0062] Example 7

[0063] To the leachate obtained in Example 1 and Comparative Example 1, NaOH-NH3·H2O was added to adjust the pH to 4 to remove iron and aluminum, and the ratio of nickel, cobalt and manganese in the filtrate obtained after filtration was adjusted to 1:1:1. Subsequently, NaOH-NH3·H2O was added to adjust the pH to 11 to precipitate nickel, cobalt and manganese, and Na2CO3 was added to the filtrate obtained after filtration for evaporation and crystallization to obtain Li2CO3.

[0064] Regeneration: After the obtained nickel-cobalt-manganese co-precipitate and Li2CO3 are evenly mixed, the molar ratio of lithium to transition metal is controlled to be 1.05:1, and then annealed at 800°C for 10h to obtain a regenerated positive electrode active material.

[0065] The regenerated active material (active material), PVDF, and conductive carbon black are mixed in a weight ratio of 8:1:1 to form a slurry and coated on the positive electrode current collector, and then dried to obtain a positive electrode to be tested;

[0066] In a glove box, 1M LiPF6 was used as the electrolyte (EC:DEC:EMC=1:1:1), and the separator was Celgard2400 polypropylene film. Lithium was used as the counter electrode, and the obtained regenerated positive electrode was used as the working electrode to assemble a CR2025 battery. At room temperature and a rate of 1C, the regenerated positive electrode of Example 1 and Comparative Example 1 showed a reversible capacity of 185 mAh / g and 155 mAh / g, respectively.

Claims

1. A method for fully leaching positive electrode active materials of waste lithium-ion batteries, characterized in that: The waste positive electrode material separated from the waste lithium ion battery is mixed with a 0.1-1M aqueous solution of formula 1, and leached at a temperature of 40-100° C., followed by solid-liquid separation to obtain a leachate enriched with metal ions in the material to be treated; The R is a saturated carbon chain of C1 to C6.

2. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: The waste positive electrode material is obtained by stripping the positive electrode of waste lithium-ion batteries; Preferably, the waste positive electrode material contains positive electrode active material; and is also allowed to contain at least one component of a current collector, a binder, a conductive agent, and an electrolyte.

3. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 2, characterized in that: The positive electrode active material is a transition metal oxide containing lithium; Preferably, the transition metal in the positive electrode active material includes at least one of nickel, cobalt and manganese; Preferably, the positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and nickel-cobalt-manganese ternary; Preferably, the content of active material in the waste positive electrode material is above 50 wt.%, more preferably above 80 wt.%, and further preferably 80 to 95 wt.%.

4. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: In the formula 1, R is methylene, 1,2-ethylene, 1,3-propylene or 1,4-butylene.

5. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: The concentration of Formula 1 in the aqueous solution of the Formula 1 leaching agent is 0.1 to 0.7M.

6. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: The liquid-to-solid ratio in the leaching stage is 20-40 mL / g.

7. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: The temperature during the leaching stage is 45-85°C; Preferably, the leaching stage is carried out with the assistance of ultrasound; Preferably, the power of ultrasound is 100-500W.

8. The method for fully leaching the positive electrode active material of waste lithium-ion batteries according to claim 1, characterized in that: The leaching time is 0.5 h or longer, preferably 1 to 4 h.

9. A method for regenerating positive electrode active materials of waste lithium-ion batteries, characterized in that: The full leaching method according to any one of claims 1 to 8 is used for leaching treatment to obtain the leaching solution, the leaching solution is subjected to co-precipitation treatment, filtered to obtain a precursor and a lithium solution, the lithium solution is subjected to lithium precipitation treatment to obtain a lithium source, the precursor is calcined with lithium to obtain a regenerated positive electrode active material.

10. A regenerated positive electrode active material obtained by the regeneration method according to claim 9.

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