Method of recycling li-ion battery

Abstract

According to one aspect of the proposed invention, at least one of lithium, nickel, cobalt, and manganese can be recovered in an environmentally friendly manner by performing solvometallurgical electrochemical oxidation dissolution and contacting Aliquat 336 with the deep eutectic solvent (DES) mixed with cathode material powder.

Description

Technology Field

[0001] A method for recycling lithium-ion batteries, specifically a technology for recycling the cathode material of a lithium-ion battery using a deep eutectic solvent and an ionic liquid, is disclosed. Background Technology

[0002] Lithium-ion batteries (LIBs) are widely used in automobiles, industrial equipment, home appliances, etc., and contain at least one of the following metals: lithium, nickel, cobalt, manganese, titanium, aluminum, and iron.

[0003] For example, currently known battery cathode materials consist of components such as LCO (Lithium-Cobalt-Oxide), LFP (Lithium-Iron-Phosphate), LMO (Lithium-Manganese-Oxide), LTO (Lithium-Titanium-Oxide), NCA (Nickel-Cobalt-Aluminum), or NCM (Nickel-Cobalt-Manganese).

[0004] As the volume of spent LIBs increases, their manufacturing and disposal are becoming political and environmental issues requiring appropriate solutions. Furthermore, with global reserves of lithium, cobalt, nickel, and other metals becoming increasingly limited and unevenly distributed, research into lithium-ion battery recycling technologies is becoming crucial from both economic and environmental perspectives.

[0005] U.S. Patent Publication No.: US20200399737, “Recycling Li-ion batteries using green chemicals and processes”) discloses a process for extracting, recovering, and recycling metals and materials from spent lithium-ion batteries (LIBs), which involves recovering dissolved metal ions from a deep eutectic solvent and then regenerating the cathode material; however, this process is handled in a high-temperature environment and causes problems such as the formation of toxic substances. The problem to be solved

[0006] The proposed invention presents a method for extracting and recovering important metals from waste lithium-ion batteries by processing them in a more environmentally friendly manner, which are difficult to recycle without using non-environmentally friendly chemical application methods (e.g., hydrometallurgy) or / and high-temperature treatment methods (e.g., pyrometallurgy). means of solving the problem

[0007] According to one aspect of the proposed invention, at least one of lithium, nickel, cobalt, and manganese can be extracted and recovered in an environmentally friendly manner by performing solvometallurgical electrochemical oxidation dissolution and contacting Aliquat 336 with the deep eutectic solvent (DES) mixed with cathode material powder. Effects of the invention

[0008] According to the proposed invention, waste lithium-ion batteries can be recycled in a more environmentally friendly manner.

[0009] According to the proposed invention, limited resources can be conserved and resources can be utilized economically.

[0010] According to the proposed invention, the recovery rate of the lithium-ion battery cathode material can be improved.

[0011] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings. Brief explanation of the drawing

[0012] FIG. 1 illustrates a lithium-ion battery recycling method according to one embodiment. FIG. 2 illustrates a preprocessing step according to one embodiment. FIG. 3 illustrates a separation step according to one embodiment. FIG. 4 illustrates a recovery step according to one embodiment. FIG. 5 illustrates a precipitate formation step according to one embodiment. FIG. 6 is a flowchart illustrating a lithium-ion battery recycling method according to one embodiment. Specific details for implementing the invention

[0013] The foregoing and additional aspects are embodied through embodiments described with reference to the accompanying drawings. It is understood that the components of each embodiment may be combined in various ways within the embodiment or with components of other embodiments, unless otherwise stated or contradicted. Based on the principle that the inventor may appropriately define the concepts of terms to best describe his invention, the terms used in this specification and claims shall be interpreted in a meaning and concept consistent with the description or proposed technical idea. Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] FIG. 1 illustrates a lithium-ion battery recycling method according to one embodiment. As illustrated, the lithium-ion battery recycling method (S1000) includes a pretreatment step (S100, PRE-TREATMENT), a separation step (S200, SEPARATION), and a recovery step (S300, RECOVERY). The pretreatment step (S100) is a step of performing electrochemical oxidation dissolution, the separation step (S200) is a step of performing solvent extraction, and the recovery step (S300) means a step of forming a chemical precipitation and recovering.

[0015] The pretreatment step (S100) may utilize the solvometallurgical electrochemical oxidation dissolution method. Solvometallurgy refers to a smelting technology that extracts metal from ore, waste, etc., using a non-aqueous solution. Solvometallurgy has the advantage of adopting a low-temperature treatment method, similar to hydrometallurgy, and furthermore, it can be an environmentally friendly method as it uses less water.

[0016] FIG. 2 illustrates a pretreatment step according to one embodiment, FIG. 3 illustrates a separation step according to one embodiment, and FIG. 4 illustrates a recovery step according to one embodiment.

[0017] In FIG. 2, the pretreatment step (S100, PRE-TREATMENT) may include an electrolytic cell preparation step (S110, PROVIDING ELECTROLYTIC CELL), a cathode material mixing step (S120, MIXING WITH CATHODE MATERIAL), a cathode material coating step (S130, CATHODE MATERIAL PAINTED), and an electrochemical oxidation dissolution step (S140, ELECTROCHEMICAL OXIDATION DISSOUTION).

[0018] In FIG. 3, the separation step (S200, SEPARATION) includes an Aliquat 336 contact step (S210, CONTACTING WITH Aliquat 336) and a solvent extraction step (S220, EXTRACTING SOLVENT), and may further include a residue step (S230, REMAINING), a movement step (S240, MOVING), an Aliquat 336 stripping step (S250, STRIPPING Aliquat 336), and a D2EHPA contact step (S260, CONTACTING WITH D2EHPA). The separation step (200) of FIG. 3 may be described in more detail by FIG. 6.

[0019] In FIG. 4, the recovery step (S300, RECOVERY) may include a sediment formation step (S310, FORMING PRECIPITATION) and a sediment recovery step (S320, RECOVERING PRECIPITATION).

[0020] <Description of Claim 1>

[0021] A lithium-ion battery recycling method (S1000) for recovering metal from a waste lithium-ion battery according to one embodiment comprises a pretreatment step (S100) for performing electrochemical oxidation dissolution, a separation step (S200) for performing solvent extraction, and a recovery step (S300) for forming a chemical precipitate.

[0022] The pretreatment step (S100) may include an electrolytic cell preparation step (S110), a cathode material mixing step (S120), a cathode material coating step (S130), and an electrochemical dissolution step (S140).

[0023] In the step of preparing an electrolytic cell (S110), an electrolytic cell may be prepared in which a (+) electrode and a (-) electrode are disposed at the bottom and a deep eutectic solvent (DES) containing choline chloride:ethylene glycol (ChCl:EG) is contained. Choline chloride:ethylene glycol (ChCl:EG) may refer to a mixture of choline chloride and ethylene glycol. The electrolytic cell may be an H-shaped electrolytic cell (H-cell) commonly used in laboratories.

[0024] According to one embodiment, the (+) electrode or the (-) electrode may be coated with iridium oxide. For example, the (+) electrode or the (-) electrode may be a titanium mesh electrode coated with IrO or IrO2. This may promote oxidation.

[0025] In the cathode material mixing step (S120), a powder of cathode material from a waste lithium-ion battery containing at least one of lithium, nickel, cobalt, and manganese can be mixed in a deep eutectic solvent (DES).

[0026] Deep eutectic solvents (DES) refer to cases where two or more compounds form a eutectic mixture through hydrogen bonding, resulting in a melting point much lower than the original. Because they possess properties similar to ionic liquids, they have recently been gaining attention as eco-friendly solvents with advantages such as non-flammability, biodegradability, biocompatibility, and designability.

[0027] In the cathode material coating step (S130), the cathode material powder of the spent lithium-ion battery may be painted onto the (+) electrode or the (-) electrode. It may be painted onto the (+) electrode or the (-) electrode in the form of a paste (LIBs:DES paste) formed by mixing the cathode material of the spent lithium-ion battery with a deep eutectic solvent.

[0028] In the electrochemical dissolution step (S140), solvometallugical electrochemical oxidation dissolution can be performed by applying a power supply voltage to the (+) electrode and the (-) electrode. In this process, lithium (Li), nickel (Ni), cobalt (CO), or manganese (Mn) lose electrons, and each Ni 2+ , Li + , Co 2+ , Mn 2+ It can be oxidized to. In the electrochemical dissolution step (S140), lithium (Li), nickel (Ni), cobalt (Co), or manganese (Mn) may be dissolved.

[0029] The separation step (S200) may include an Aliquat 336 contact step (S210) and a solvent extraction step (S220). In the Aliquat 336 contact step (S210), Aliquat 336 may be contacted with the deep eutectic solvent (DES) mixed with the cathode material powder. Aliquat 336 may be located at the bottom and the deep eutectic solvent (DES) at the top. Generally, Aliquat 336 and the deep eutectic solvent (DES) do not mix due to their material properties.

[0030] Aliquat 336 (A336), an ionic liquid, can be selected as an extractant and a DES-immiscible secondary phase because it recovers metal complexes through ion exchange.

[0031] In the solvent extraction step (S220), cationic species Li+ and [Ni(EG)3]2+ and anionic species [CoCl4] 2- and [MnCl4] 2- Solvents can be extracted based on differences in speciation or speciation between them.

[0032] Because ethylene glycol molecules do not carry a self-charge, nickel is a cationic species [Ni(EG)3] 2+ It can be preferentially bonded by three ethylene glycol molecules that induce the formation of.

[0033] In addition, cobalt and manganese both consist of four chloride ions (Cl - It preferentially binds to the anionic species [CoCl4] 2- and [MnCl4] 2- It can form. Since four chloride ions carry a single negative charge, 2 from each central metal ion + Remove to make the entire species 2 - It can generate electric charge.

[0034] Therefore, the charged species present in ChCl-EG DES, namely the cationic 2 + Species [Ni(EG)3] 2+ and, anionic 2 - Species [CoCl4] 2- and (versus) [MnCl4] 2- Based on this speciation or differentiation (Speciation) "Difference" in anionic 2 - Species [CoCl4] 2- and [MnCl4] 2- cationic species Li + and [Ni(EG)3] 2+ A solvent extraction process can be applied to selectively separate from.

[0035] The recovery step (S300) may include a precipitate formation step (S310) and a precipitate recovery step (S320). In the precipitate formation step (S310), at least one of lithium, nickel, cobalt, and manganese may be chemically precipitated by combining with CO3 or (OH)2. In the precipitate recovery step (S320), the chemically precipitated precipitate may be recovered from a deep eutectic solvent (DES).

[0036] <Description of Claim 2>

[0037] According to one embodiment, the separation step (S200) may further include a retention step (S230) in which lithium or nickel remains in the deep eutectic solvent (DES) and a transfer step (S240) in which manganese or cobalt is transferred to Aliquat 336 (A336).

[0038] Due to differences in density and polarity, Aliquat 336 may be located at the bottom and the deep eutectic solvent (DES) at the top within the electrolytic cell. Additionally, lithium or nickel may remain in the deep eutectic solvent (DES Phase), while cobalt or manganese may migrate to the Aliquat 336 (A336 Phase) and be contained in Aliquat 336.

[0039] <Description of Claim 3>

[0040] According to one embodiment, the separation step (S200) may further include an Aliquat 336 removal step (S250) in which an aqueous sodium chloride solution (Aqueous NaCl) is added to remove Aliquat 336. Through this process, Co 2+ and Mn 2+ This can be extracted together. An aqueous sodium chloride solution can be weakly acidic, that is, have a hydrogen ion concentration of pH less than 7.0.

[0041] <Description of Claim 4>

[0042] According to one embodiment, the separation step (S200) may further include a D2EHPA contact step (S260), in which a solution of di-2-ethylhexyl phosphate (D2EHPA) dissolved in heptane or menthol-thymol DES is contacted with a deep eutectic solvent (DES) from which Aliquat 336 has been removed. Through this process, Co 2+ , Mn 2+ can be extracted separately. For example, Mn 2+ is contained in a solution of di-2-ethylhexyl phosphate (D2EHPA) dissolved in heptane or menthol-thymol DES, and Co 2+ It can be included in an aqueous solution.

[0043] <Description of the Invention of Claims 5, 6, 7, 8, and 9>

[0044] FIG. 5 illustrates a precipitation formation step according to one embodiment. As illustrated, the precipitation formation step (S310, FORMING PRECIPITATION) may include at least one of a lithium carbonate formation step (S310-1, FORMING Li2CO3), a nickel hydroxide formation step (S310-2, FORMING Ni(OH)2), a cobalt hydroxide formation step (S310-3, FORMING Co(OH)2), and a manganese hydroxide formation step (S310-4, FORMING Mn(OH)2). As a result, a specific metal may be formed in a solid state and chemically precipitated.

[0045] According to one embodiment, in the lithium carbonate formation step (S310-1), sodium carbonate (Na2CO3) may be added to form chemically precipitated lithium carbonate (Li2CO3).

[0046] According to one embodiment, in the nickel hydroxide formation step (S310-2), sodium hydroxide (NaOH) is added to form chemically precipitated nickel hydroxide (Ni(OH)2).

[0047] According to one embodiment, in the cobalt hydroxide formation step (S310-3), sodium hydroxide (NaOH) is added to form chemically precipitated cobalt hydroxide (Co(OH)2).

[0048] According to one embodiment, in the manganese hydroxide formation step (S310-4), sodium hydroxide (NaOH) can be added to form chemically precipitated manganese hydroxide (Mn(OH)2).

[0049] According to one embodiment, the manganese hydroxide forming step (S310-4) may form manganese hydroxide (Mn(OH)2) in a heptane:D2EHPA or menthol-thymol:D2EHPA solvent system. Heptane:D2EHPA refers to a mixture of heptane and D2EHPA (di-2-ethylhexylphosphoric acid), and menthol-thymol:D2EHPA may refer to a mixture of menthol-thymol and D2EHPA.

[0050] FIG. 6 is a flowchart illustrating a lithium-ion battery recycling method according to one embodiment. As illustrated, the lithium-ion battery recycling method includes a pretreatment step (S100, PRE-TREATMENT), a separation step (S200, SEPARATION), and a recovery step (S300, RECOVERY), and a detailed description of each step can be combined by reference with the above-mentioned content.

[0051] By performing solvometallurgical electrochemical oxidation dissolution and contacting Aliquat 336 with the deep eutectic solvent (DES) mixed with cathode material powder, lithium, nickel, cobalt, and / or manganese can be recovered in an environmentally friendly manner in the form of Li2CO3, Ni(OH)2, Co(OH)2, and / or Mn(OH)2.

[0052] In the present invention, the term "anode material" is a broad concept encompassing composite metal materials constituting lithium ions, and even commercial methods not referred to as "anode materials" may fall within the scope of equivalence to the present invention. In addition to the lithium, nickel, cobalt, and manganese mentioned above, important metals such as titanium, aluminum, and iron can be extracted and recovered by the present invention.

[0053] Furthermore, the present invention is not limited to batteries, and any method for extracting a specific metal from a composite metal may be included in the present invention.

[0054] Although the present invention has been described above with reference to embodiments with reference to the accompanying drawings, it is not limited thereto and should be interpreted to encompass various variations that can be obviously derived from them by those skilled in the art. The claims are intended to encompass such variations.

Claims

Claim 1 A pretreatment step (S100) for performing electrochemical oxidation dissolution; a separation step (S200) for performing solvent extraction; A lithium-ion battery recycling method (S1000) for recovering metal from a waste lithium-ion battery, comprising a recovery step (S300) for forming a chemical precipitate, wherein the pretreatment step (S100) comprises: an electrolytic cell preparation step (S110) in which an electrolytic cell is provided, wherein a (+) electrode and a (-) electrode are disposed at the bottom and a deep eutectic solvent (DES) containing choline chloride:ethylene glycol (ChCl:EG) is contained therein; a cathode material mixing step (S120) in which a cathode material powder of a waste lithium-ion battery comprising at least one of lithium, nickel, cobalt, and manganese is mixed with the deep eutectic solvent (DES); and a cathode material coating step (S130) in which the cathode material powder of a waste lithium-ion battery is painted onto the (+) electrode or the (-) electrode. The method comprises an electrochemical dissolution step (S140) in which solvometallugical electrochemical oxidation dissolution is performed by applying a power supply voltage to the (+) electrode and the (-) electrode, wherein nickel is formed as the cationic species [Ni(EG)₃]² and cobalt and manganese are differentiated into the anionic species [CoCl₄]² and [MnCl₄]², respectively, by binding with chloride ions; and the separation step (S200) comprises an Aliquat 336 contact step (S210) in which Aliquat 336 is contacted with the deep eutectic solvent (DES) mixed with the cathode powder, and Li, which is a cationic species + and [Ni(EG)3] 2+ Wow, [CoCl4], an anionic species 2- and [MnCl4] 2- A lithium-ion battery recycling method comprising: a solvent extraction step (S220) in which a solvent is extracted based on the speciation difference between the two; and a recovery step (S300) comprising: a precipitate formation step (S310) in which at least one of lithium, nickel, cobalt, and manganese is chemically precipitated in the form of a precipitate; and a precipitate recovery step (S320) in which the chemically precipitated precipitate is recovered from the deep eutectic solvent (DES). Claim 2 A lithium-ion battery recycling method according to claim 1, wherein the separation step (S200) further comprises: a retention step (S230) in which lithium or nickel remains in the deep eutectic solvent (DES); and a transfer step (S240) in which cobalt or manganese is transferred to the Aliquat 336. Claim 3 A lithium-ion battery recycling method according to claim 1, wherein the separation step (S200) further comprises: an Aliquat 336 removal step (S250) in which Aliquat 336 is removed by adding an aqueous sodium chloride solution. Claim 4 A lithium-ion battery recycling method according to claim 1, wherein the separation step (S200) further comprises: a D2EHPA contact step (S260) in which a solution of di-2-ethylhexyl phosphate (D2EHPA) dissolved in heptane or menthol-thymol DES is contacted with a deep eutectic solvent (DES) from which Aliquat 336 has been removed. Claim 5 A lithium-ion battery recycling method according to claim 1, wherein the precipitate forming step (S310) comprises: a lithium carbonate forming step (S310-1) in which lithium carbonate (Li2CO3) is formed by adding sodium carbonate to chemically precipitate. Claim 6 A lithium-ion battery recycling method according to claim 1, wherein the precipitate forming step (S310) comprises: a nickel hydroxide forming step (S310-2) in which chemically precipitated nickel hydroxide (Ni(OH)2) is formed by adding sodium hydroxide. Claim 7 A lithium-ion battery recycling method according to claim 1, wherein the precipitate forming step (S310) comprises: a cobalt hydroxide forming step (S310-3) in which cobalt hydroxide (Co(OH)2) is formed by adding sodium hydroxide to chemically precipitate; Claim 8 A lithium-ion battery recycling method according to claim 4, wherein the precipitate forming step (S310) comprises: a manganese hydroxide forming step (S310-4) in which chemically precipitated manganese hydroxide (Mn(OH)2) is formed by adding sodium hydroxide. Claim 9 A lithium-ion battery recycling method according to claim 8, wherein the manganese hydroxide forming step (S310-4) forms manganese hydroxide (Mn(OH)2) in a solvent system of :heptane:D2EHPA or menthol-thymol:D2EHPA.

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