Precursor material for positive electrode active material and method for producing positive electrode active material for lithium secondary battery, and positive electrode active material for lithium secondary battery produced thereby

Abstract

The present invention provides a method for producing a cathode active material precursor material using used lithium secondary batteries with a high nickel content, a method for producing a cathode active material for lithium secondary batteries containing the cathode active material precursor material produced thereby, and a cathode active material for lithium secondary batteries produced thereby.

Description

[Technical field]

[0001] The present invention relates to a method for producing a positive electrode active material precursor material using waste lithium secondary batteries with a high nickel content, a method for producing a positive electrode active material for lithium secondary batteries using the positive electrode active material precursor material produced thereby, and a positive electrode active material for lithium secondary batteries produced thereby. [Background technology]

[0002] The demand for secondary batteries as energy sources is growing rapidly as technological development and demand for various types of energy storage devices, from ultra-small to medium-sized, are increasing in mobile devices, laptops, wireless devices, electric cars, electric motorcycles, etc. Among these secondary batteries, lithium secondary batteries, which exhibit high energy density and operating potential, long cycle life, and low self-discharge rate, have been commercialized and are widely used.

[0003] A lithium secondary battery is generally composed of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte, and is charged and discharged by the intercalation / de-intercalation of lithium ions. Lithium secondary batteries have the advantages of high energy density, large electromotive force, and high capacity, and are therefore used in a variety of fields.

[0004] In particular, it is expected that the use of ternary (Ni, Co, Mn) positive electrode active materials will increase significantly for large-capacity lithium secondary batteries, and as high capacity and high output are simultaneously required, positive electrode materials with a layered structure with a high Ni content are being developed to achieve high energy density and high output. As the production and use of lithium secondary batteries increases, the amount of waste also increases, and the need for reprocessing and recycling technologies for waste lithium secondary batteries for disposal is growing. In addition, the secondary battery and material-related industries are in a severe price competition, and efforts such as low-cost raw materials, low-cost processes, and improved yields are urgently needed. In addition, as the demand for secondary batteries increases, there are also increasing attempts to reuse waste batteries after use, defective products generated during the manufacturing process, and electrodes.

[0005] In order to recover and reuse a transition metal such as nickel from the used lithium secondary batteries, an additional step must be performed in order to separate a positive electrode active material from the used batteries, separate the transition metals from the separated positive electrode active material, purify the material, and then use it again as a raw material for manufacturing a positive electrode active material.

[0006] For example, Korean Patent Publication No. 10-2011-0036628 discloses a method for producing valuable metal powders including lithium, nickel, cobalt, and manganese from waste batteries, leaching the valuable metal powders with acid in a reducing atmosphere to produce a leaching solution, and producing nickel, cobalt, and manganese hydroxides and lithium carbonate (Li2CO3) from the leaching solution. However, this method has problems in that it is not possible to separate each transition metal component individually, and thus the form of use is limited, and in order to adjust the composition to a desired ratio when used as a positive electrode active material, a separate transition metal salt must be added, and even after the transition metal components are extracted, considerable energy and time are required to remove impurities.

[0007] In addition, among the methods for reprocessing metal oxide-based positive electrode active materials for lithium secondary batteries, methods for separating and recovering manganese, nickel, and cobalt from the positive electrode active material by precipitation and / or solvent extraction are being researched. However, as the production and use of lithium secondary batteries with a high nickel content increases, there is an increasing need to develop a method for separating nickel with high purity and high yield from used lithium secondary batteries with a high nickel content and using it to manufacture positive electrode active materials. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-2011-0036628 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to improve the above-mentioned problems of the conventional technology, and has an object to provide a method for producing a positive electrode active material precursor material using used lithium secondary batteries with a high nickel content, a method for producing a positive electrode active material for lithium secondary batteries using the positive electrode active material precursor material produced thereby, and a positive electrode active material for lithium secondary batteries produced thereby. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides a method for producing a positive electrode active material precursor material using used lithium secondary batteries, the method comprising the steps of: (1) leaching a positive electrode active material of used lithium secondary batteries to obtain a leachate; and (2) adding 2 to 20 w / v % of an oxime-based substance to the leachate to precipitate nickel.

[0011] The present invention also provides a method for producing a positive electrode active material precursor material, comprising the steps of: mixing a positive electrode active material precursor material produced by the method for producing a positive electrode active material precursor material and a lithium salt; x Co y Mn zProvided is a method for producing a positive electrode active material for a lithium secondary battery, which is characterized by obtaining a positive electrode active material represented by O2 (where 0 < x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1, and x + y + z = 1).

[0012] Further, the present invention provides a positive electrode active material for a lithium secondary battery produced by the method for producing a positive electrode active material for a lithium secondary battery.

Effects of the Invention

[0013] The method for producing a positive electrode active material precursor of the present invention can recover high-purity nickel from the positive electrode active material of a waste lithium secondary battery with a high nickel content at a high recovery rate, can recover the nickel in the form of a sulfate, and does not require a separate additional process when producing a positive electrode active material using the recovered product, thus providing the effect of being immediately usable as a positive electrode active material precursor.

Brief Description of the Drawings

[0014] [Figure 1] It is a manufacturing flowchart of a positive electrode active material precursor according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0015] The present invention relates to a method for producing a positive electrode active material precursor using a waste lithium secondary battery, including a step of precipitating nickel from the positive electrode active material of a waste lithium secondary battery with a high nickel content, a method for producing a positive electrode active material for a lithium secondary battery using the positive electrode active material precursor produced by the production method, and a positive electrode active material for a lithium secondary battery produced by the method for producing a positive electrode active material for a lithium secondary battery.

[0016] Specifically, the method for producing a positive electrode active material precursor material of the present invention is characterized by having a high concentration of an oxime-based substance, which has a very low solubility in water and alcohol of 1 w / v % or less in the prior art and is therefore difficult to apply to the recovery of positive electrode active materials containing high concentrations of nickel, in particular. By utilizing this for nickel recovery, high-purity nickel can be recovered at a high recovery rate from the positive electrode active material of used lithium secondary batteries having a high nickel content. In addition, since the nickel is recovered in the form of a sulfate and a separate additional process is not required when producing a positive electrode active material using the recovered material, the method for producing a positive electrode active material using the recovered material provides the effect that the material can be immediately used as a positive electrode active material precursor material.

[0017] In the method for producing a positive electrode active material precursor material of the present invention, the recovery rate of nickel from the waste lithium secondary battery positive electrode active material may be 60% or more, preferably 80% or more, more preferably 85% or more, and most preferably 90% or more, and the purity of nickel recovered by the method for producing a positive electrode active material precursor material of the present invention may be 90% or more, and is preferably 99% or more.

[0018] Hereinafter, a method for producing a cathode active material precursor material according to the present invention, a method for producing a cathode active material for a lithium secondary battery using the cathode active material precursor material produced thereby, and a cathode active material for a lithium secondary battery produced by the above-mentioned production method will be described in detail, but the present invention is not limited thereto.

[0019] <Method of manufacturing a precursor material for a positive electrode active material> The method for producing a positive electrode active material precursor material of the present invention is characterized by including a step of adding 2 to 20 w / v % of an oxime-based substance as a precipitating agent to precipitate nickel, and specifically may include a step of (1) leaching the positive electrode active material of a waste lithium secondary battery to obtain a leachate, and (2) adding 2 to 20 w / v % of an oxime-based substance to the leachate to precipitate nickel.

[0020] (1) A step of leaching the positive electrode active material of the waste lithium secondary battery to obtain a leachate. In the method for producing a positive electrode active material precursor material of the present invention, the positive electrode active material of the waste lithium secondary battery is not particularly limited as long as it contains nickel or a nickel salt, but may be a two-component positive electrode active material containing nickel and one or more of cobalt and manganese, or a three-component positive electrode active material containing nickel, cobalt and manganese, and preferably the molar ratio of nickel in the three components may be 50% to 90%, and it is preferable that the molar ratio of nickel is 60% to 80%.

[0021] As an example, the positive electrode active material of the waste lithium secondary battery of the present invention may include a positive electrode active material represented by the following Chemical Formula 1.

[0022] [C1] LiNi x Co y Mn z O2 In the above formula 1, 0.5≦x≦1, 0≦y≦0.3, 0≦z≦0.3, and x+y+z=1, and preferably, 0.5≦x≦0.9, 0.1≦y≦0.3, 0.1≦z≦0.3, and x+y+z=1.

[0023] Examples of the substance that leaches out the positive electrode active material include sulfuric acid and hydrogen peroxide. Specifically, the positive electrode active material of the present invention is not particularly limited in terms of nickel content. 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), as well as NCM523 (LiNi 0.5 Co 0.2 Mn 0.3It also has an excellent nickel recovery effect for NCM523, NCM622, and NCM811. Here, NCM523 means that nickel (N), cobalt (C), and manganese (M) are produced in a ratio of 5:2:3, NCM622 means that nickel, cobalt, and manganese are produced in a ratio of 6:2:2, and NCM811 means that nickel, cobalt, and manganese are produced in a ratio of 8:1:1.

[0024] In addition, the leachate may contain Li, Mn, Co, and Ni, and the method for producing a positive electrode active material precursor material of the present invention may further include a step of extracting manganese from the leachate in step (1), and the manganese can be extracted by solvent extraction.

[0025] The method for producing a positive electrode active material precursor material of the present invention may further include a step of immediately crushing the used lithium secondary batteries and then heat treating them as a pretreatment step for obtaining a positive electrode active material from the used lithium secondary batteries.

[0026] The pretreatment process may further include a step of discharging the used lithium secondary batteries before crushing them. Once the discharge is complete, the subsequent valuable metal recovery process can be safely carried out in air rather than in an inert atmosphere. The discharge may be carried out in a discharge solution. Distilled water may be used as the discharge solution. The degree of completion of the discharge may be confirmed by a voltage reduction over time. Most of the electrolyte in the used lithium secondary batteries is removed during the discharge process.

[0027] The crushing may be performed by milling, which may be mechanical milling, specifically, by one or more mills selected from the group consisting of a roll mill, a ball mill, a jet mill, a planetary mill, and an attrition mill.

[0028] The crushed material may have a particle size of 1 to 15 μm, preferably 1 to 7 μm, and more preferably 2 to 5 μm.

[0029] The pretreatment process may further include a classification step after the crushing, in which the crushed material is separated into a large fraction of fine electrode composite powder and other components (positive electrode, negative electrode, and separator) through a classification process, preferably through a sieve, and the electrode composite powder is recovered from the crushed material.

[0030] In the pretreatment process, a gravity separation step may be further included after the classification. The crushed material is subjected to gravity separation, preferably using a rinse tank with a water level, whereby the separator in the crushed material is removed and the electrode composite, separator, current collector, etc. can be separated.

[0031] In the pretreatment process, a magnetic separation step may be further included after the gravity separation. If the waste lithium secondary batteries further contain stainless steel (SUS), the stainless steel (SUS) is separated and removed from the crushed material by magnetic separation.

[0032] In the pretreatment step, a heat treatment may be performed after the magnetic separation. The heat treatment is for removing impurities other than the positive electrode active material, such as a positive electrode binder, a positive electrode conductive material, a negative electrode active material, a negative electrode binder, a negative electrode conductive material, and a pouch, contained in the waste lithium secondary batteries, and may be performed at a temperature range of 600°C to less than 1000°C, preferably at a temperature range of 700°C to 900°C, and more preferably at a temperature range of 800°C to 900°C. When the heat treatment temperature is 1000°C or higher, even lithium in the positive electrode active material can be removed.

[0033] Furthermore, the method for producing a positive electrode active material precursor material of the present invention may include a step of mixing sulfuric acid with the pretreatment material after the heat treatment to further remove impurities such as remaining carbon material (negative electrode active material) and copper.

[0034] The used lithium secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolyte, and may further include a pouch. Specifically, the used lithium secondary battery includes a separator between a negative electrode and a positive electrode, and an electrolyte solution including an electrolyte is supplied to the separator. More specifically, the used lithium secondary battery may be manufactured by, for example, sequentially stacking the negative electrode, the separator, and the positive electrode, winding or folding the stack, and placing the stack in a cylindrical or square battery case or pouch, and then injecting an organic electrolyte solution into the battery case or pouch.

[0035] The positive electrode of the waste lithium secondary battery may contain lithium metal or lithium transition metal oxide, and may be prepared by a conventional method known in the art, for example, by mixing and stirring a positive electrode active material with a solvent and, if necessary, a binder, a conductive material, and a dispersant to prepare a slurry, which is then applied (coated) to a positive electrode current collector, compressed, and then dried.

[0036] The positive electrode active material of the waste lithium secondary battery includes a positive electrode active material represented by the following Chemical Formula 1, and preferably has a high nickel content.

[0037] [C1] LiNi x Co y Mn z O2 In the above formula 1, 0.5≦x≦1, 0≦y≦0.3, 0≦z≦0.3, and x+y+z=1, and preferably, 0.5≦x≦0.9, 0.1≦y≦0.3, 0.1≦z≦0.3, and x+y+z=1.

[0038] The solvent for the positive electrode may be N-methyl-2-pyrrolidone (NMP), acetone, water, or a mixture thereof, and the conductive material for the positive electrode may be a conductive assistant such as polyacrylic acid, acetylene black, furnace black, graphite, carbon fiber, or fullerene.

[0039] The positive electrode binder serves to firmly adhere the positive electrode active material particles to each other and to firmly adhere the positive electrode active material to the positive electrode current collector. For example, the binder may be polyacrylic acid, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butylene rubber, fluororubber, or various copolymers.

[0040] The positive electrode current collector is not particularly limited as long as it has a thickness of about 3 μm to about 500 μm and has high conductivity without causing chemical changes in the battery, and may be, for example, stainless steel, aluminum, nickel, titanium, heat-treated carbon, or aluminum or stainless steel surface-treated with a material selected from the group consisting of carbon, nickel, titanium, silver, and combinations thereof. The current collector may have fine irregularities on its surface to increase the adhesive strength of the positive electrode active material, and may be in various forms such as a film, sheet, foil, net, porous body, foam, or nonwoven fabric.

[0041] The negative electrode of the used lithium secondary battery may be prepared by a conventional method known in the art, for example, by mixing and stirring a negative electrode active material with a solvent and, if necessary, a binder, a conductive material, and a dispersant to prepare a slurry, applying (coating) the slurry to a negative electrode current collector, compressing it, and drying it.

[0042] The negative electrode active material may be a carbon material capable of absorbing and releasing lithium ions, lithium metal, silicon, or tin. Preferably, the negative electrode active material may be a carbon material, and examples of the carbon material include low-crystalline carbon and high-crystalline carbon. Typical low-crystalline carbons include soft carbon and hard carbon, and typical high-crystalline carbons include natural graphite, kish graphite, pyrolytic carbon, mesophase pitch based carbon fiber, carbon microbeads, mesophase pitches, and high-temperature fired carbons such as petroleum or coal tar pitch derived cokes.

[0043] The solvent for the negative electrode may be N-methyl-2-pyrrolidone (NMP), acetone, water, or a mixture thereof. The conductive material for the negative electrode may be a conductive assistant such as polyacrylic acid, acetylene black, furnace black, graphite, carbon fiber, or fullerene.

[0044] The binder of the negative electrode serves to effectively adhere the negative electrode active material particles to each other and to effectively adhere the negative electrode active material to the current collector. For example, the binder may be polyacrylic acid, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butylene rubber, fluororubber, or various copolymers.

[0045] The negative electrode current collector is generally made to a thickness of about 3 μm to about 500 μm. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and may include, for example, copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, or silver, or an aluminum-cadmium alloy. In addition, like the positive electrode current collector, the surface can be formed with fine irregularities to strengthen the binding force of the negative electrode active material, and it can be used in various forms such as a film, sheet, foil, net, porous body, foam, or nonwoven fabric.

[0046] The separator of the waste lithium secondary battery may be, but is not limited to, a porous substrate made of a polyolefin-based polymer selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-methacrylate copolymer, a porous substrate made of a polymer selected from the group consisting of polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfite, and polyethylenenaphthalene, or a porous substrate formed of a mixture of inorganic particles and binder polymer. In particular, in order to easily transfer the lithium ions of the lithium ion supply core to the external electrode, it is preferable to use a separator made of a nonwoven material corresponding to a porous substrate made of a polymer selected from the group consisting of polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfite, polyethylenenaphthalene, and combinations thereof.

[0047] The separation membrane has a pore size of about 0.01 μm to about 10 μm, and the thickness is generally about 5 μm to about 300 μm.

[0048] The electrolyte of the waste lithium secondary battery may be, for example, a gel-type polymer electrolyte using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAC, or a solid electrolyte using PEO, PPO (polypropylene oxide), PEI (polyethylene imine), PES (polyethylene sulphide), or PVAc (polyvinyl acetate). Also, the electrolyte may be a non-aqueous electrolyte using ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), gamma-butyrolactone (γ-BL), sulfolane, methyl acetate (MA), or methyl propionate (MP). The electrolyte may further contain a lithium salt, and examples of such lithium salts include LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, or lithium tetraphenylborate may also be used.

[0049] In one embodiment of the present application, the waste lithium secondary battery may use an organic solid electrolyte and / or an inorganic solid electrolyte in addition to the separator, but is not limited thereto. In this case, when the organic solid electrolyte and / or the inorganic solid electrolyte is used, the solid electrolyte may also function as the separator, so that the separator may not be used.

[0050] The organic solid electrolyte may include, but is not limited to, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyvinyl alcohol, or polyvinylidene fluoride.The inorganic solid electrolyte may include, but is not limited to, Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2, and combinations thereof.

[0051] (2) Nickel precipitation step The method for producing a positive electrode active material precursor material according to the present invention includes a step of adding an oxime-based substance to the leachate at a concentration of 2 w / v % or more, preferably 2 to 20 w / v %, and more preferably 10 to 20 w / v %, to precipitate nickel.

[0052] In the present invention, the nickel concentration of the leachate may be more than 10 g / L, is preferably 20 g / L or more, and is more preferably 20 to 50 g / L. The present invention can recover high-purity nickel in high yield even from a leachate containing nickel at a high concentration of 20 g / L or more.

[0053] In the present invention, the oxime-based substance may include one or more selected from the group consisting of dimethylglyoxime (DMG), diethylglyoxime, dipropylglyoxime, and ethylmethylglyoxime.

[0054] In particular, among the oxime-based substances, dimethylglyoxime has been used as an indicator to confirm the presence or absence of nickel through a color change of the precipitate, but it is difficult to prepare it at a concentration of 2 w / v% or more, and therefore it could not be practically used in processes such as recovery of positive electrode active materials. In the present invention, an oxime-based substance with a concentration of 2 w / v% or more that can be used for recovery of nickel is prepared, and the high-concentration oxime-based substance is precipitated in a nickel-containing leachate, thereby separating nickel salts.

[0055] In the step (2), the 2 to 20 w / v % oxime-based substance may be obtained through a saponification step. Therefore, the manufacturing method of the positive electrode active material precursor material according to the present invention may further include a step of saponifying the oxime-based substance to obtain a 2 to 20 w / v % oxime-based solution in the step (2). In the present invention, the oxime-based substance that precipitates nickel is an organic substance having a significantly low solubility of less than 1 w / v % in a polar solvent such as water. Therefore, in the present invention, the oxime-based substance is saponified to improve its solubility in a polar solvent, thereby obtaining a 2 to 20 w / v % oxime-based substance.

[0056] Specifically, the method may include mixing a polar solvent and an alkaline solution to saponify the oxime-based substance, and then dissolving the oxime-based substance to obtain the oxime-based solution. For example, the alkaline solution may be at least one selected from the group consisting of NaOH, KOH, Ca(OH)2, and NH4OH, and the oxime-based substance may be in a form dissolved in a polar solvent, and the concentration of the oxime-based substance therein may be 2 to 20 w / v%, preferably 5 to 15 w / v%. The polar solvent may be at least one selected from the group consisting of water, alcohol, acetone, and carboxylic acid.

[0057] In the present invention, the oxime solution may contain an oxime substance saponified to 40% or more, preferably 50% or more, and as the Ni content increases, it is preferable that the oxime substance is saponified to 100%. For example, when NCM523 waste batteries are used, 80% or more of nickel can be recovered with a 50% saponified oxime substance, and when NCM811 waste batteries are used, 80% or more of nickel can be recovered with a 100% saponified oxime substance, but is not limited thereto.

[0058] The degree of saponification of the oxime-based solution can be adjusted according to the amount of the alkaline solution added. For example, when the alkaline solution is added in an amount corresponding to 100% of the moles of the oxime-based substance, a 50% saponified oxime-based solution can be obtained, and when the alkaline solution is added in an amount corresponding to 200% of the moles of the oxime-based substance, a 100% saponified oxime-based solution can be obtained.

[0059] The step of precipitating nickel includes, when the pH of the leachate is 4 to 6, preferably pH 6, precipitating the leachate using the oxime-based solution to obtain a Ni salt.

[0060] In addition, the method for producing a positive electrode active material precursor material according to the present invention may further include a step of treating the precipitated nickel with sulfuric acid to obtain nickel sulfate (NiSO4) in step (2). By recovering the nickel in the form of sulfate, it can be immediately used as a positive electrode active material precursor for lithium secondary batteries without a separate treatment process.

[0061] In the method for producing a positive electrode active material precursor material of the present invention, the recovery rate of nickel from the positive electrode active material of the waste lithium secondary battery may be 60% or more, preferably 80% or more, more preferably 85% or more, and most preferably 90% or more, and even under high nickel concentration conditions where the nickel content in the positive electrode active material of the waste lithium secondary battery is high, a recovery rate of nickel of 80% or more can be exhibited. The purity of nickel recovered by the method for producing a positive electrode active material precursor material of the present invention is preferably 99% or more.

[0062] (3) Obtaining additional positive electrode active material precursor material The method for producing a positive electrode active material precursor material according to the present invention may further include a step of extracting manganese and / or a step of extracting cobalt, which is a step before and / or after the step (1) and / or the step (2).

[0063] Specifically, the step of extracting manganese includes a step of obtaining manganese (Mn) salt by solvent extraction of the leachate containing manganese using a phosphoric acid-based substance at a pH of 3 to 4, and the manganese salt is manganese sulfate (MnSO4). The phosphoric acid-based substance is a manganese salt extractant, and can include a substance that can extract Mn salt with an efficiency of 80% or more when the leachate has a pH of 3 to 4, preferably pH 3.5 to 4, and more preferably pH 4. The extraction efficiency of the Mn salt may be 80% or more, preferably 85% or more, and more preferably 90% or more. The phosphoric acid-based substance may contain, for example, di-(2-ethylhexyl)phosphoric acid [Di-(2-ethylhexyl)phosphoric acid, D2EHPA] or 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (PC88A), and is preferably di-(2-ethylhexyl)phosphoric acid.

[0064] The step of extracting manganese may be included in the step before the step (2) after the step (1).

[0065] Specifically, the step of extracting the cobalt includes the step of extracting a leachate containing cobalt with a phosphoric acid-based substance at pH 4 to 5 to obtain a cobalt (Co) salt, and the cobalt salt includes cobalt sulfate (CoSO4). The phosphoric acid-based substance is a cobalt leaching agent, and when the pH of the leachate is 4 to 5, preferably pH 4.5 to 5, more preferably pH 5, it can include a substance capable of extracting Co salt with an efficiency of 80% or more. The extraction efficiency of the Co salt may be 80% or more, preferably 85% or more, more preferably 90% or more. The phosphoric acid-based substance may include, for example, di-(2-ethylhexyl) phosphoric acid [Di-(2-ethylhexyl)phosphoric acid, D2EHPA] or 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester, PC88A), and is preferably di-(2-ethylhexyl) phosphoric acid.

[0066] <Method for manufacturing a positive electrode active material for a lithium secondary battery> Further, the present invention provides a method for manufacturing a positive electrode active material for a lithium secondary battery, characterized by mixing a positive electrode active material precursor material and a lithium salt produced by the method for manufacturing a positive electrode active material precursor material according to the present invention to obtain a positive electrode active material represented by LiNi x’ Co y’ Mn z’ O2 (where 0 < x’ ≦ 1, 0 ≦ y’ < 1, 0 ≦ z’ < 1, and x’ + y’ + z’ = 1).

[0067] The positive electrode active material produced by the present invention is not particularly limited as long as it contains nickel or a nickel salt, but may be a two-component positive electrode active material containing nickel and one or more of cobalt and manganese, or a three-component positive electrode active material containing nickel, cobalt, and manganese.

[0068] The lithium salt may be at least one selected from the group consisting of lithium carbonate and lithium hydroxide.

[0069] In the method for producing a positive electrode active material for a lithium secondary battery of the present invention, the positive electrode active material can be produced by a known production method, except that the positive electrode active material precursor material produced by the present invention is used.

[0070] <Positive electrode active material for lithium secondary batteries> The present invention also provides a positive electrode active material for a lithium secondary battery produced by the method for producing a positive electrode active material for a lithium secondary battery according to the present invention. The positive electrode active material for a lithium secondary battery of the present invention can be produced by a known production method, except that the positive electrode active material precursor material produced by the present invention is used.

[0071] [Mode for carrying out the invention] The present invention will be described in more detail with reference to the following examples. However, the following examples are provided to more specifically explain the present invention, and the scope of the present invention is not limited to the following examples.

[0072] Production of positive electrode active material precursor material As a pretreatment process for recovering nickel, 900 kg of NCM811, NCM523 or NCM111 cathode material separated from waste lithium secondary batteries was crushed and milled to a particle size of 2μm to 5μm. The obtained powder was reacted with a sulfuric acid solution for more than 6 hours to obtain a leachate containing Li, Mn, Co and Ni. Mn was extracted from the leachate containing Li, Mn, Co and Ni by solvent extraction.

[0073] <Example 1> 1) Preparation of 10 w / v% DMG solution (100% saponified) 2.2 equivalents of DMG were used relative to the Ni contained in the residual solution (Ni 29g / L) from which Mn was extracted from NCM523 waste lithium secondary batteries. Approximately 12.62g of DMG was required to precipitate 100mL of Ni 29g / L solution, and NaOH was dissolved in approximately 126mL of DI-Water to prepare a 10w / v% DMG solution. At this time, 8.69g of NaOH was used, which is 200% of the molar number of DMG. When NaOH was completely dissolved in DI-Water, DMG was added and dissolved to produce a 100% saponified DMG solution.

[0074] 2) Preparation of nickel sulfate solution The extraction residue from which Mn was recovered from NCM523 waste lithium secondary batteries was adjusted to pH 5.0. The temperature was then maintained at 80°C, and the previously prepared 100% saponified 10 w / v% DMG solution was added dropwise. The temperature was maintained for 30 minutes or more while stirring. When the reaction was completed, the solution was cooled to room temperature and filtered to obtain a precipitate. The precipitate was washed with DI-Water and treated with sulfuric acid to obtain a high-purity nickel sulfate solution.

[0075] FIG. 1 shows a process for producing a precursor material for a positive electrode active material according to an embodiment of the present invention. <Example 2> 1) Preparation of 20 w / v% DMG solution (100% saponified) 2.2 equivalents of DMG were used relative to the Ni contained in the residual solution (Ni 29g / L) from which Mn was extracted from NCM523 waste lithium secondary batteries. Approximately 12.62g of DMG was required to precipitate 100mL of Ni 29g / L solution, and to prepare a 20w / v% DMG solution, NaOH was first dissolved in approximately 63mL of DI-Water. At this time, 8.69g of NaOH, which is 200% of the molar number of DMG, was used. When NaOH was completely dissolved in DI-Water, DMG was added and dissolved to produce a 100% saponified DMG solution.

[0076] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that the 20 w / v % DMG solution of saponified 100% was used.

[0077] <Example 3> 1) Preparation of 10 w / v% DMG solution (saponification 50%) DMG was used in an amount of 2.2 equivalents to Ni contained in the residual solution (Ni 29g / L) from which Mn was extracted from NCM523 waste lithium secondary batteries. Approximately 12.62g of DMG was required to precipitate 100mL of Ni 29g / L solution, and NaOH was first dissolved in approximately 126mL of DI-Water (deionized water) to prepare a 10w / v% DMG solution. At this time, 4.34g of NaOH, which is 100% of the DMG mole number, was used. When NaOH was completely dissolved in DI-Water, DMG was added and dissolved to obtain a 50% saponified DMG solution.

[0078] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that the prepared saponified 50% 10 w / v % DMG solution was used.

[0079] <Example 4> 1) Preparation of 10 w / v% DMG solution (100% saponified) 2.2 equivalents of DMG were used relative to the Ni contained in the residual solution (Ni 47g / L) from which Mn was extracted from NCM811 waste lithium secondary batteries. Approximately 20.46g of DMG was required to precipitate 100mL of Ni 47g / L solution, and to prepare a 10w / v% DMG solution, NaOH was first dissolved in approximately 204mL of DI-Water. At this time, 13.6g of NaOH, which is 200% of the molar number of DMG, was used. When NaOH was completely dissolved in DI-Water, DMG was added and dissolved to produce a 100% saponified DMG solution.

[0080] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that an extraction residue (Ni 47 g / L) obtained from NCM811 waste lithium secondary batteries was used.

[0081] <Example 5> 1) Preparation of 10 w / v% DMG solution (saponification 50%) 2.2 equivalents of DMG were used relative to the Ni contained in the extraction residue (Ni 47g / L) from which the Mn was extracted, obtained from NCM811 waste lithium secondary batteries. Approximately 20.46g of DMG was required to precipitate 100mL of Ni 47g / L solution, and to prepare a 10w / v% DMG solution, NaOH was first dissolved in approximately 204mL of DI-Water (deionized water). At this time, 6.8g of NaOH, which is 100% of the DMG mole number, was used. When NaOH was completely dissolved in DI-Water, DMG was added and dissolved to obtain a 50% saponified DMG solution.

[0082] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that the extraction residue (Ni 47 g / L) obtained from NCM811 used lithium secondary batteries and the 10 w / v % DMG solution of 50% saponification prepared above were used.

[0083] <Comparative Example 1> 1) Preparation of 1 w / v% DMG solution (0% saponification) 2.2 equivalents of DMG were used for the Ni contained in the residual solution (Ni 9.66g / L) from which Mn was extracted from NCM111 waste lithium secondary batteries. 4.2g of DMG was used to precipitate 100mL of Ni 9.66g / L solution, which was then dissolved in ethanol to prepare a 1w / v% DMG solution.

[0084] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that the extraction residue (Ni 9.66 g / L) obtained from NCM111 waste lithium secondary batteries and the 1 w / v % DMG solution prepared above were used.

[0085] <Comparative Example 2> 1) Preparation of 1 w / v% DMG solution (0% saponification) DMG was used in an amount of 2.2 equivalents to the Ni contained in the residual solution (Ni 29g / L) from which Mn was extracted from NCM523 waste lithium secondary batteries. Approximately 12.62g of DMG was used to precipitate 100mL of Ni 29g / L solution, and this was dissolved in ethanol to produce a DMG solution of approximately 1w / v%.

[0086] 2) Preparation of nickel sulfate solution A high purity nickel sulfate solution was obtained in the same manner as in Example 1, except that the prepared 1 w / v % DMG solution was used.

[0087] The recovery rates and purities of nickel obtained in Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0088] [Table 1]

[0089] Referring to Table 1, when DMG was saponified by 50% or more, even in the extraction residue obtained from waste batteries containing a high concentration of nickel, high purity nickel of 99% or more was obtained at a recovery rate of 89% or more.

[0090] In contrast, when non-saponified DMG was used, a recovery rate of 88% was observed when recovering nickel from waste batteries with a low nickel content, but when nickel was extracted from batteries with a high nickel content, the nickel recovery rate was significantly low at 16%.

Claims

1. (1) leaching a positive electrode active material of a used lithium secondary battery to obtain a leachate; (2) adding 2 to 20 w / v % of an oxime-based substance to the leachate to precipitate nickel; A method for producing a positive electrode active material precursor material using a waste lithium secondary battery, comprising: In the step (2), the 2 to 20 w / v % oxime-based substance is obtained through a saponification step, The saponification of the oxime-based substance includes mixing a polar solvent with an alkaline solution, and then dissolving the oxime-based substance to obtain an oxime-based solution.

2. The method for producing a precursor material for a positive electrode active material according to claim 1 , wherein the positive electrode active material of the waste lithium secondary battery comprises a positive electrode active material represented by the following Chemical Formula 1: [Chemical formula 1] L)) ｘ Co ｙ Mn ｚ O ２ (In the above Chemical Formula 1, 0.5≦x≦1, 0≦y≦0.3, and 0≦z≦0.3; x+y+z=1.)

3. 2. The method for producing a positive electrode active material precursor material according to claim 1, further comprising the step of extracting manganese from the leachate after the step (1) and before the step (2).

4. 2. The method for producing a positive electrode active material precursor according to claim 1, wherein the oxime-based substance is at least one selected from the group consisting of dimethylglyoxime, diethylglyoxime, dipropylglyoxime, and ethylmethylglyoxime.

5. The alkaline solution is NaOH, KOH, Ca(OH) ２ , and N.H. ４ 2. The method for producing a precursor material for a positive electrode active material according to claim 1, wherein the precursor material is at least one selected from the group consisting of OH.

6. 2. The method for producing a positive electrode active material precursor according to claim 1, wherein the polar solvent is at least one selected from the group consisting of water, alcohol, acetone, and carboxylic acid.

7. 2. The method for producing a positive electrode active material precursor material according to claim 1, further comprising the step of treating the precipitated nickel with sulfuric acid to obtain nickel sulfate in the step (2).

8. 2. The method for producing a precursor material for a positive electrode active material according to claim 1, wherein the positive electrode active material of the waste lithium secondary batteries is obtained by crushing the waste lithium secondary batteries and then heat-treating them.

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