Preparation method for cathode material precursor using taylor-couette flow apparatus

Abstract

To provide a preparation method for a cathode material precursor using a Taylor-Couette flow apparatus.SOLUTION: A preparation method for a cathode material precursor using the Taylor-Couette flow apparatus includes forming and continuously outputting a first product stream containing core particles by supplying a first reaction solution, which is a multi-metal solution, to a first Taylor-Couette flow apparatus and performing a co-precipitation reaction, supplying the first product stream to a second Taylor-Couette flow apparatus connected in series with the first Taylor-Couette flow apparatus, and supplying a second reaction liquid, which is a transition metal aqueous solution, to the second Taylor-Couette flow apparatus, reacting it with the core particles, and forming a cathode material precursor having a core-shell structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for preparing a cathode material precursor, and in particular to a method for preparing a cathode material precursor using a Taylor-Couette flow apparatus. [Background technology]

[0002] Nickel-rich ternary or quaternary cathode materials have the advantages of high energy density and low cost, but due to the limitations of mechanical properties and electrical conductivity of the cathode materials, the structure of the cathode materials is easily collapsed and dissolved after repeated charging and discharging, resulting in poor cycle stability.

[0003] In conventional technology, in order to improve the service life, the surface of ternary or quaternary cathode materials is coated with functional materials to prevent the corrosion of hydrofluoric acid (hydrogen fluoride, HF), reduce side reactions between the electrode material and the electrolyte, inhibit the dissolution of metal ions, and reduce damage to the material structure during repeated charging and discharging, thereby further improving the recyclability of the materials.

[0004] However, conventional methods for preparing cathode material precursors have various drawbacks, such as the impregnation method not being capable of continuous production, the dry coating method being prone to uneven distribution of materials, and the sputtering and atomic layer deposition methods using expensive equipment that does not allow for continuous production. Summary of the Invention [Problem to be solved by the invention]

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for preparing a cathode material precursor using a Taylor-Couette flow apparatus. [Means for solving the problem]

[0006] In order to solve the above technical problems, one technical solution adopted in the present invention provides a method for preparing a cathode material precursor using a Taylor-Couette flow apparatus. The method for preparing a cathode material precursor using the Taylor-Couette flow apparatus includes a first Taylor-Couette reaction step of supplying a first reaction solution, which is a multimetal solution, to a first Taylor-Couette flow apparatus to carry out a co-precipitation reaction to form a first product stream containing a plurality of core particles, and continuously outputting the first product stream; a second Taylor-Couette reaction step of supplying the first product stream to a second Taylor-Couette flow apparatus connected in series (for example, via a pipe) to the first Taylor-Couette flow apparatus, and supplying a second reaction solution, which is a coating material aqueous solution, to the second Taylor-Couette flow apparatus, so that the second reaction solution forms a functional coating layer on each of the outer surfaces of the plurality of core particles, thereby forming a second product stream containing a plurality of cathode material precursors having a core-shell structure, the coating material aqueous solution being an aqueous transition metal solution; and a purification step of purifying the second product stream to purify and separate the plurality of cathode material precursors having a core-shell structure from the second product stream.

[0007] Preferably, the polymetallic solution contains at least three or more of a nickel (Ni) compound, a cobalt (Co) compound, a manganese (Mn) compound, a magnesium (Mg) compound, and an aluminum (Al) compound, and the core particles are at least one selected from the group consisting of ternary alloy hydroxide core particles and quaternary alloy hydroxide core particles.

[0008] Preferably, the aqueous transition metal solution is at least one selected from the group consisting of a zirconium ion solution, a tungsten ion solution, an aluminum ion solution, a zinc ion solution, a titanium ion solution, a molybdenum ion solution, and a tin ion solution.

[0009] Preferably, a second reaction solution flow rate at which the second reaction solution is supplied to the second Taylor-Couette flow apparatus is 3% to 20% of a first reaction solution flow rate at which the first reaction solution is supplied to the first Taylor-Couette flow apparatus.

[0010] Preferably, a first reaction solution flow rate for supplying the first reaction solution to the first Taylor-Couette flow apparatus is 0.5 mL / min to 3 mL / min, a second reaction solution flow rate for supplying the second reaction solution to the second Taylor-Couette flow apparatus is 0.05 mL / min to 0.30 mL / min, and the second reaction solution flow rate is 3% to 20% of the first reaction solution flow rate.

[0011] Preferably, the first reaction temperature in the first Taylor-Couette flow apparatus is 45° C. to 70° C., and the rotation speed of the first rotary motor of the first Taylor-Couette flow apparatus is 500 rpm to 900 rpm.

[0012] Preferably, the second reaction temperature in the second Taylor-Couette flow apparatus is 45° C. to 70° C., and the rotation speed of the second rotary motor of the second Taylor-Couette flow apparatus is 400 rpm to 800 rpm.

[0013] Preferably, the first Taylor-Couette reaction step includes forming a reaction mixture by supplying a first chelating agent and a first precipitating agent to the first Taylor-Couette flow apparatus so as to mix with the first reaction solution, and a first residence time of the reaction mixture in the first Taylor-Couette flow apparatus is 300 minutes to 600 minutes.

[0014] Preferably, the second Taylor-Couette reaction step includes forming another reaction mixture by supplying a second chelating agent and a second precipitating agent to the second Taylor-Couette flow apparatus, respectively, to mix with the second reaction liquid, and a second residence time of the another reaction mixture in the second Taylor-Couette flow apparatus is 150 minutes to 500 minutes, and the second residence time is 50% to 85% of the first residence time.

[0015] Preferably, in the cathode material precursor having a core-shell structure, the average core particle diameter (D 50 ) is 4 μm to 12 μm, and the thickness of the functional coating layer is 1% to 20% of the core particle diameter of the core particle. Effect of the Invention

[0016] As an advantageous effect of the present invention, the method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to the present invention includes a first Taylor-Couette reaction step of supplying a first reaction liquid, which is a multimetal solution, to a first Taylor-Couette flow apparatus and carrying out a coprecipitation reaction to form a first product stream containing a plurality of core particles and continuously outputting the first product stream; and a second Taylor-Couette flow apparatus connected in series to the first Taylor-Couette flow apparatus and supplying a second reaction liquid, which is an aqueous coating material solution, to the second Taylor-Couette flow apparatus. and a purification step of purifying and separating the plurality of the core-shell structured cathode material precursors from the second product stream by purifying the second product stream." The technical features of this invention can replace the traditional continuous stirring reactor and achieve the purpose of continuous production.

[0017] Here, the first Taylor-Couette flow apparatus is used to form core particles (i.e., core portions) with uniform element distribution and dense structure by coprecipitation, while the second Taylor-Couette flow apparatus is used to form a cathode material precursor having a core-shell structure by performing a surface coating treatment on the core particles.

[0018] The present invention can continuously form a cathode material precursor having a core-shell structure, which can effectively improve the stability and durability of lithium batteries while simultaneously achieving the safety of the materials. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of an apparatus for producing a cathode material precursor using Taylor-Couette reactors according to an embodiment of the present invention. [Figure 2A] 1 is a SEM photograph of a cathode material having a core-shell structure according to an embodiment of the present invention. [Figure 2B] 1 is a SEM photograph of a core particle cathode material having only a single layer in Comparative Example 1. [Figure 3A] 4 is a SEM photograph of a cathode material having a core-shell structure according to Example 3 of the present invention after 500 charge-discharge cycle measurements have been performed. [Figure 3B] 1 is a SEM photograph of a cathode material having a core-shell structure according to Comparative Example 1 of the present invention after 500 charge-discharge cycle measurements have been performed. [Figure 4A] 3B is a SEM photograph of a cross section of the cathode material of FIG. 3A. [Figure 4B] 3C is a SEM photograph of a cross section of the cathode material of FIG. 3B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In order to better understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings, which are provided for reference and explanation only and are not intended to limit the scope of the present invention.

[0021] Hereinafter, the embodiments of the present invention will be described in accordance with certain specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention based on the contents disclosed in this specification. The present invention can be implemented or applied in other different specific embodiments, and various modifications and changes can be made to each detail in this specification based on different perspectives and applications without departing from the concept of the present invention. In addition, as described in advance, the accompanying drawings of the present invention are simple schematic illustrations and are not drawn based on actual size. The technical contents of the present invention will be described in more detail based on the following embodiments, but the disclosed contents do not limit the protection scope of the present invention.

[0022] It should be understood that although the present specification may use terms such as "first," "second," and "third" to describe various materials or parameters, these materials or parameters are not limited by these terms, and the term "or" as used herein may include any one or more combinations of the associated listed items, depending on the actual situation.

[0023] As shown in FIG. 1, an embodiment of the present invention provides a method for preparing a cathode active material precursor using Taylor-Couette reactors to produce a cathode active material precursor having a core-shell structure.

[0024] In this embodiment, the cathode material precursor is a lithium salt (e.g., LiOH·H 2 O) as an active agent for mixing with the glycerol ester, but the invention is not limited thereto.

[0025] More specifically, the method for preparing a cathode material precursor using the Taylor-Couette flow apparatus includes steps S110, S120, and S130.

[0026] The step S110 is to carry out a first Taylor-Couette reaction step. The first Taylor-Couette reaction step includes supplying a first reaction liquid to a first Taylor-Couette flow device 1 through a first reaction liquid supply unit 11, and carrying out a coprecipitation reaction to form a first product flow P1 including a plurality of core particles. The core particles have the characteristics of uniform element distribution and dense structure. Here, each of the core particles is at least one selected from the group consisting of ternary alloy hydroxide core particles and quaternary alloy hydroxide core particles.

[0027] The first reaction liquid is a multi-metal solution.

[0028] In one embodiment of the present invention, the multi-metal solution contains at least three or more of a nickel (Ni) compound, a cobalt (Co) compound, a manganese (Mn) compound, a magnesium (Mg) compound, and an aluminum (Al) compound. Preferably, the multi-metal solution contains at least a nickel (Ni) compound, a cobalt (Co) compound, and a manganese (Mn) compound, and does not contain a magnesium (Mg) compound and an aluminum (Al) compound, or may further contain at least one or more of a magnesium (Mg) compound and an aluminum (Al) compound.

[0029] In one embodiment of the present invention, for example, the nickel compound is nickel sulfate (NiSO 4 ), and the cobalt compound may be cobalt sulfate (CoSO 4 ), and the manganese compound may be manganese sulfate (MnSO 4 ), and the magnesium compound may be magnesium sulfate (MgSO 4), and the aluminum compound may be (Al 2 (SO 4 ) 3 ), but the present invention is not limited thereto.

[0030] More specifically, the first Taylor-Couette flow device 1 includes a first rotating shaft 1a and a first reaction chamber 1b radially surrounding the first rotating shaft 1a.

[0031] The start position of the first Taylor-Couette flow apparatus is connected to the first reactant supply unit 11, the first chelating agent supply unit 12, and the first precipitating agent supply unit 13, respectively.

[0032] The first Taylor-Couette flow device 1 further axially connects the first rotating shaft 1a to a first rotary motor 14, and the first rotary motor 14 drives the first rotating shaft 1a to rotate it along the axial direction.

[0033] Here, the first reaction liquid supply unit 11 is arranged to supply the first reaction liquid (e.g., a multi-metal solution) to the first reaction chamber 1b of the first Taylor-Couette flow apparatus 1 via one of the first pump injection units 151 of a first pump module 15.

[0034] Here, the first chelating agent supply unit 12 supplies a first chelating agent (e.g., an aqueous ammonia solution, NH 4 OH (aq) ) is arranged to mix with the first reaction liquid (e.g., a multi-metal solution) by supplying the first reaction chamber 1 b of the first Taylor-Couette flow apparatus 1 via a first pump injection unit 152 of another one of the first pump modules 15.

[0035] Here, the first precipitant supply unit 13 supplies a first precipitant (e.g., an aqueous hydroxide solution, NaOH (aq)) via yet another first pump injection unit 153 of a first pump module 15 to a first reaction chamber 1b of the first Taylor-Couette flow apparatus 1, thereby mixing the first reaction liquid (e.g., a multi-metal solution) with a first chelating agent (e.g., an aqueous ammonia solution) to form a reaction mixture and perform the co-precipitation reaction.

[0036] The first rotary motor 14 drives the first rotating shaft 1a to rotate it along the axial direction, thereby completely reacting a reaction mixture formed by a first reaction liquid (e.g., a multi-metal solution), a first chelating agent (e.g., an aqueous ammonia solution), and a first precipitating agent (e.g., an aqueous hydroxide solution) supplied to the first reaction chamber 1b of the first Taylor-Couette flow apparatus.

[0037] A first product stream P1 formed in the first Taylor-Couette reaction step and including a plurality of core particles can be continuously output through at least one outlet of the first Taylor-Couette flow apparatus 1.

[0038] In the first Taylor-Couette reaction step, a first pH value monitoring unit 16 is connected to the rear side of the outlet of the first Taylor-Couette flow apparatus 1 for monitoring the first pH value of the first product stream P1.

[0039] In one embodiment of the present invention, in order to improve the reaction efficiency of the first Taylor-Couette reaction step, the first reaction temperature of the first Taylor-Couette flow apparatus is 45°C to 70°C, preferably 50°C to 65°C.

[0040] The first motor speed at which the first rotary motor 14 drives and rotates the first rotating shaft 1a is between 500 rpm and 900 rpm, and preferably between 500 rpm and 700 rpm.

[0041] The first residence time of the reaction mixture formed from the first reaction liquid, the first chelating agent, and the first precipitating agent in the first Taylor-Couette flow apparatus is 300 minutes to 600 minutes, and preferably 450 minutes to 550 minutes.

[0042] The first reaction liquid (e.g., a multi-metal solution) is supplied to the first reaction chamber 1b of the first Taylor-Couette flow apparatus 1 via the first reaction liquid supply unit 11 at a flow rate of 0.5 mL / min to 3 mL / min, and preferably 1.0 mL / min to 2.5 mL / min.

[0043] The flow rate of the first chelating agent (e.g., an aqueous ammonia solution) supplied to the first reaction chamber 1b of the first Taylor-Couette flow apparatus 1 via the first chelating agent supply unit 12 is 0.2 mL / min to 0.8 mL / min, and preferably 0.4 mL / min to 0.7 mL / min.

[0044] By controlling a first precipitant flow rate of the first precipitant (e.g., an aqueous hydroxide solution) supplied to the first reaction chamber 1b of the first Taylor-Couette flow apparatus 1 via a first precipitant supply unit 13, a first pH value of the first product stream P1 is controlled to be 10-12.

[0045] Here, the concentration of the hydroxide solution is 3M to 5M NaOH. (aq) However, the present invention is not limited to this.

[0046] In the first product stream P1, the core particles (ternary alloy hydroxide or quaternary alloy hydroxide) have a core particle diameter of 4 μm to 12 μm, and preferably 6 μm to 10 μm.

[0047] In one embodiment of the present invention, the core particle may be a nickel-cobalt-manganese ternary alloy hydroxide, a nickel-cobalt-manganese-magnesium quaternary alloy hydroxide, or a nickel-cobalt-manganese-aluminum quaternary alloy hydroxide, but the present invention is not limited thereto.

[0048] The step S120 is a second Taylor-Couette reaction step, which includes supplying the first product stream P1 (including a plurality of core particles) continuously produced in the first Taylor-Couette flow apparatus 1 to a second Taylor-Couette flow apparatus 2 connected in series to the first Taylor-Couette flow apparatus 1, and supplying a second reaction liquid to a second Taylor-Couette flow apparatus 21, so that the second reaction liquid performs a surface coating modification reaction on the outer surfaces of the plurality of core particles, forming a functional coating layer on each outer surface of the core particles, and forming a second product stream P2 including a plurality of cathode material precursors having a core-shell structure (e.g., a core-shell structure in which a layer is coated on the outer surface of a core particle).

[0049] Here, the second reaction liquid is a coating material aqueous solution. In this embodiment, the second reaction liquid is a transition metal aqueous solution.

[0050] For example, the aqueous transition metal solution is at least one selected from the group consisting of a zirconium ion solution, a tungsten ion solution, an aluminum ion solution, a zinc ion solution, a titanium ion solution, a molybdenum ion solution, and a tin ion solution, and is preferably a zirconium ion solution, a tungsten ion solution, or an aluminum ion solution, but the present invention is not limited thereto.

[0051] In one embodiment of the present invention, the zirconium ion solution is a zirconium sulfate solution, the tungsten ion solution is a solution prepared by dissolving sodium tungstate dihydrate and sodium hypophosphite in deionized water, and the aluminum ion solution is a solution prepared by dissolving aluminum nitrate in deionized water, but the present invention is not limited thereto.

[0052] More specifically, the second Taylor-Couette flow device 2 includes a first rotation axis 2a and a second reaction chamber 2b radially surrounding the second rotation axis 2a. In this embodiment, the second Taylor-Couette flow device 2 is disposed at the rear side of the first Taylor-Couette flow device 1 substantially along the axial direction and receives the first product stream P1 output from the first Taylor-Couette flow device 1.

[0053] The starting position of the second Taylor-Couette flow apparatus (e.g., a position close to the first Taylor-Couette flow apparatus 1) is connected to the second reaction solution supply unit 21, the second chelating agent supply unit 22, and the second precipitating agent supply unit 23, respectively.

[0054] In this embodiment, the position where the second reaction liquid supply unit 21 injects the second reaction liquid (e.g., a coating material aqueous solution) into the second Taylor-Couette flow apparatus 2 and the position where the first product stream P1 into the second Taylor-Couette flow apparatus 2 are symmetrical to each other in the radial direction of the second Couette-Taylor reactor 2 so that the first product stream P1 is in sufficient contact with the second reaction liquid, but the present invention is not limited thereto.

[0055] The second Taylor-Couette flow device 2 further connects the second rotating shaft 2a to a second rotary motor 24 in the axial direction, and the second rotary motor 24 drives the second rotating shaft 2a to rotate along the axial direction.

[0056] Here, the first product stream P1 is fed to a second reaction chamber 2b of a second Taylor-Couette flow apparatus 2 via yet another first pump injection unit 154 of the first pump module 15.

[0057] The second reaction liquid supply unit 21 is arranged to supply the second reaction liquid (e.g., an aqueous coating material solution) to the second reaction chamber 2b of the second Taylor-Couette flow apparatus 2 via one of the second pump injection units 251 of the second pump module 25.

[0058] Here, the second chelating agent supply unit 22 supplies a second chelating agent (e.g., aqueous ammonia solution, NH 4 OH (aq) ) into a second reaction chamber 2 b of the second Taylor-Couette flow apparatus 2 via another second pump injection unit 252 of a second pump module 25, thereby mixing the second reaction liquid (e.g., an aqueous coating material solution) with the first product stream of a plurality of core particles.

[0059] Here, the second precipitant supply unit 23 supplies a second precipitant (e.g., an aqueous hydroxide solution, NaOH (aq) ) via yet another second pump injection unit 253 of the second pump module 25 to the second reaction chamber 2b of the second Taylor-Couette flow apparatus 2, thereby mixing the second reaction liquid (e.g., an aqueous coating material solution), a second chelating agent (e.g., an aqueous ammonia solution), and a first product stream P1 containing a plurality of core particles to perform the surface treatment.

[0060] With the above-described configuration, the second Taylor-Couette flow apparatus 2 subsequently forms and outputs a second product stream including a cathode material precursor having a plurality of core-shell structures (e.g., a core-shell structure in which the outer surface of a core particle is coated with a functional coating layer).

[0061] In the second Taylor-Couette reaction step, a second pH value monitoring unit 26 is connected to the rear side of the outlet of the second Taylor-Couette flow apparatus 2 for monitoring the second pH value of the second product stream P2.

[0062] In one embodiment of the present invention, in order to improve the reaction efficiency of the second Taylor-Couette reaction process, the second reaction temperature of the second Taylor-Couette flow apparatus 2 is 45°C to 70°C, preferably 50°C to 65°C.

[0063] The second motor speed at which the second rotary motor 24 drives and rotates the second rotating shaft 2a is between 400 rpm and 800 rpm, preferably between 400 rpm and 700 rpm. Preferably, the second motor speed is lower than the first motor speed of the first rotary motor 14, although the invention is not limited thereto.

[0064] The second residence time of the reaction mixture formed of the second reaction liquid, the second chelating agent, and the second precipitating agent in the second Taylor-Couette flow apparatus 2 is 150 minutes to 500 minutes, and preferably 240 minutes to 400 minutes. Preferably, the second residence time of the reaction mixture in the second Taylor-Couette flow apparatus 2 is 50% to 85% of the first residence time of the reaction mixture in the first Taylor-Couette flow apparatus 1, but the present invention is not limited thereto.

[0065] The second reaction liquid flow rate of the second reaction liquid (e.g., coating material aqueous solution) supplied to the second reaction chamber 2b of the second Taylor-Couette flow apparatus 2 via the second reaction liquid supply unit 21 is 0.05 mL / min to 0.30 mL / min, and preferably 0.10 mL / min to 0.25 mL / min. More specifically, the second reaction liquid flow rate is 3% to 20% of the first reaction liquid flow rate (multi-metal solution flow rate) in the first Taylor-Couette flow apparatus, and preferably 8% to 15%.

[0066] The second chelating agent flow rate of the second chelating agent (e.g., an aqueous ammonia solution) supplied to the second reaction chamber 2b of the second Taylor-Couette flow apparatus 2 via the second chelating agent supply unit 22 is 0.1 mL / min to 0.6 mL / min, and preferably 0.1 mL / min to 0.5 mL / min.

[0067] The second pH value of the second product stream P2 is controlled to 10-12 by controlling the second precipitant flow rate of the second precipitant (e.g., aqueous hydroxide solution) supplied to the second reaction chamber 2b of the second Taylor-Couette flow apparatus 2 via the second precipitant supply unit 23. Here, the concentration of the aqueous hydroxide solution is 3M-5M NaOH. (aq) However, the present invention is not limited to this.

[0068] In the second product flow P2, the cathode material precursor includes a core particle (core layer) and a functional coating layer (shell layer) coated on the outer surface of the core particle. 50 ) is 4 μm to 12 μm, and preferably 6 μm to 10 μm.

[0069] The thickness of the functional coating layer is 1% to 20% of the core particle diameter of the core particle, and preferably 1% to 15%, but the present invention is not limited thereto.

[0070] In one embodiment of the present invention, the core particle may be a nickel-cobalt-manganese ternary alloy hydroxide, a nickel-cobalt-manganese-magnesium quaternary alloy hydroxide, or a nickel-cobalt-manganese-aluminum quaternary alloy hydroxide.

[0071] The functional coating layer is a coating layer containing a transition metal (for example, zirconium, tungsten, aluminum) to protect the core particle.

[0072] It is worth noting that, in the parameters of the manufacturing conditions shown in this embodiment, the volume of the Taylor-Couette flow apparatus is 1 liter (L), but the present invention is not limited thereto. The volume of the Taylor-Couette flow apparatus can be expanded to 10 L to 1000 L for reaction, and the manufacturing conditions can be adjusted accordingly.

[0073] More specifically, step S130 includes a purification step, which includes purifying a second product stream P2 including a cathode material precursor having a core-shell structure output from the second Taylor-Couette flow apparatus 2, thereby purifying the cathode material precursor from the second product stream P2.

[0074] More specifically, the purification step includes filtering the second product stream P2 to obtain a cathode material precursor, and washing and drying the cathode material precursor to obtain a purified cathode material precursor.

[0075] In one embodiment of the present invention, the purified cathode material precursor and a lithium-containing compound (i.e., a lithium source) are mixed and ball-milled to obtain a crude cathode oxide product, which is then calcined by introducing oxygen using a high-temperature tubular furnace to obtain a cathode oxide for use as a lithium battery cathode material.

[0076] In this embodiment, the lithium-containing compound is lithium hydroxide (ie, LiOH) and the cathode oxide is a nickel-rich cathode oxide, although the invention is not so limited.

[0077] As described above, an embodiment of the present invention provides a method for preparing a cathode material precursor using a Taylor-Couette flow apparatus, in which a cathode material precursor is prepared in a continuous preparation manner by two directly connected Taylor-Couette flow apparatuses, a first Taylor-Couette flow apparatus and a second Taylor-Couette flow apparatus.

[0078] Here, the first Taylor-Couette flow apparatus is used to form core particles (i.e., core portions) with uniform element distribution and dense structure by coprecipitation, while the second Taylor-Couette flow apparatus is used to form a cathode material precursor having a core-shell structure by performing a surface coating treatment on the core particles.

[0079] The embodiment of the present invention can continuously prepare a cathode material precursor having a core-shell structure (i.e., a nickel-rich ternary / quaternary cathode material composite precursor having a core-shell structure), and can effectively improve the stability and durability of the battery by coating and surface treating the cathode material precursor with a functional material under the action of high energy density, thereby achieving high gram capacity and capacity retention rate while simultaneously achieving safety.

[0080] In the method according to the embodiment of the present invention, two directly connected first and second Taylor-Couette flow devices are adopted instead of the conventional continuous stirring reactor, and the precursor is produced by co-precipitation. The particle size, crystallinity, and specific surface area of ​​the precursor are controlled by controlling the reaction temperature, motor speed, and dropping time of the precipitant. Thus, the method according to the embodiment of the present invention is suitable for industrial continuous production.

[0081] In a method according to an embodiment of the present invention, an aqueous solution of coating material is passed through a second Taylor-Couette flow apparatus, and the core particles are heat-treated and coated with the Taylor flow to form a functional coating layer.

[0082] Since the functional coating layer has a thin and uniform thickness, the cathode core particles are completely coated so that the cathode core particles are not affected by the electrolyte, and the occurrence of side reactions can be suppressed.

[0083] The method according to the embodiment of the present invention can improve the shortcomings of the conventional production method. For example, the dipping method cannot be continuously produced, the dry coating method is easily unevenly distributed, and the sputtering method and the atomic layer deposition method are expensive and cannot be continuously produced. The cathode material precursor according to the embodiment of the present invention has fewer cracks after a long-term charge and discharge measurement compared with the core particles not coated with the functional coating layer, and when used in lithium batteries, the cycle life of the lithium battery is significantly improved.

[0084] [Experimental data and measurement results] The present invention will be described in detail below with reference to Examples 1 to 3 and Comparative Example 1. However, these Examples are provided for the purpose of understanding the present invention, and the present invention is not limited thereto.

[0085] <Example 1> Multimetallic solutions (i.e., NiSO 4 :CoSO 4 :MnSO 4 The first Taylor-Couette flow apparatus was charged with a mixture of 8:1:1 (molar ratio of the multi-metal solution, volume molarity of the multi-metal solution being 2 M) and a precipitant, NaOH. (aq) and chelating agent NH 4 OH (aq) was further fed into a first Taylor-Couette flow apparatus to carry out a co-precipitation reaction to form a solution containing nickel-cobalt-manganese ternary alloy hydroxide particles.

[0086] Here, the reaction temperature of the first Taylor-Couette flow apparatus is 60 °C, the motor speed is 600 rpm, the average residence time of the material is 500 min, the flow rate of the feed material (multi-metal solution) is 1.5 mL / min, and the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.

[0087] Then, the solution containing the nickel-cobalt-manganese ternary alloy hydroxide particles output from the first Taylor-Couette flow apparatus is supplied to a second Taylor-Couette flow apparatus, and a coating material aqueous solution (i.e., a zirconium sulfate solution with a volume molar concentration of 1M), another precipitant, NaOH (aq) , and another chelating agent, NH 4 OH (aq) was further fed into a second Taylor-Couette flow apparatus to form a transition metal coating material layer on the surface of the nickel-cobalt-manganese ternary alloy hydroxide particles, thereby producing a solution containing a cathode material precursor having a core-shell structure.

[0088] Here, the reaction temperature of the second Taylor-Couette flow apparatus was 60 °C, the motor speed was 600 rpm, the average residence time of the material was 377 min, the flow rate of the feed material (aqueous coating material solution) was 0.15 mL / min, and the concentration of the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.

[0089] Finally, the solution containing the cathode material precursor having the core-shell structure was filtered, washed, and dried, and then mixed with a lithium source (lithium hydroxide) and ball-milled. The mixture was then calcined by introducing oxygen in a high-temperature tubular furnace to obtain a nickel-rich cathode oxide. The electrochemical properties of the nickel-rich cathode oxide were then measured.

[0090] <Example 2> Multimetallic solutions (i.e., NiSO 4 :CoSO 4 :MnSO 4 The first Taylor-Couette flow apparatus was charged with a mixture of 8:1:1 (molar ratio of the multi-metal solution, volume molarity of the multi-metal solution being 2 M) and a precipitant, NaOH. (aq) and chelating agent NH 4 OH (aq)was further fed into the first Taylor-Couette flow apparatus to carry out a coprecipitation reaction to form an aqueous solution containing nickel-cobalt-manganese ternary alloy hydroxide particles. Here, the reaction temperature of the first Taylor-Couette flow apparatus was 60 °C, the motor speed was 600 rpm, the average residence time (residence time) of the material was 500 min, the flow rate of the feed material (multi-metal solution) was 1.5 mL / min, and the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) The pH value of the solution was controlled at 11 by adjusting the flow rate of (concentration 4 M).

[0091] Then, the solution containing the nickel-cobalt-manganese ternary alloy hydroxide particles output from the first Taylor-Couette flow apparatus was fed to a second Taylor-Couette flow apparatus, and a coating material aqueous solution (i.e., a tungsten ion solution, the volume molar concentration of which was 0.1 M), another precipitant, NaOH (aq) , and another chelating agent, NH 4 OH (aq) was further fed into a second Taylor-Couette flow apparatus to form a transition metal coating material layer on the surface of the nickel-cobalt-manganese ternary alloy hydroxide particles, thereby producing a solution containing a cathode material precursor having a core-shell structure.

[0092] Here, the reaction temperature of the second Taylor-Couette flow apparatus was 60 °C, the motor speed was 600 rpm, the average residence time of the material was 377 min, the flow rate of the feed material (aqueous coating material solution) was 0.15 mL / min, and the concentration of the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.

[0093] Finally, the solution containing the cathode material precursor having the core-shell structure was filtered, washed, and dried, and then mixed with a lithium source (lithium hydroxide) and ball-milled. The mixture was then calcined by introducing oxygen in a high-temperature tubular furnace to obtain a nickel-rich cathode oxide. The electrochemical properties of the nickel-rich cathode oxide were then measured.

[0094] <Example 3> Multimetallic solutions (i.e., NiSO 4 :CoSO 4 :MnSO 4 :MgSO 4 The first Taylor-Couette flow apparatus was charged with a mixture of 8:1:0.9:0.1 (molar ratio of the multi-metal solution is 2 M) and a precipitant, NaOH. (aq) and chelating agent NH 4 OH (aq) was further fed into a first Taylor-Couette flow apparatus to carry out a co-precipitation reaction to form a solution containing nickel-cobalt-manganese ternary alloy hydroxide particles.

[0095] Here, the reaction temperature of the first Taylor-Couette flow apparatus is 60 °C, the motor speed is 600 rpm, the average residence time of the material is 500 min, the flow rate of the feed material (multi-metal solution) is 1.5 mL / min, and the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.2.

[0096] Then, the solution containing the nickel-cobalt-manganese-aluminum quaternary alloy hydroxide particles output from the first Taylor-Couette flow apparatus was fed to a second Taylor-Couette flow apparatus, and a coating material aqueous solution (i.e., an aluminum ion solution, the solution volume molar concentration was 1M), another precipitant, NaOH (aq) , and another chelating agent, NH 4 OH (aq)was further fed into a second Taylor-Couette flow apparatus to form a transition metal coating material layer on the surface of the nickel-cobalt-manganese-aluminum quaternary alloy hydroxide particles, producing a solution containing a cathode material precursor having a core-shell structure.

[0097] Here, the reaction temperature of the second Taylor-Couette flow apparatus is 60 °C, the motor speed is 600 rpm, the average residence time of the material is 384 min, the flow rate of the feed material (aqueous coating material solution) is 0.15 mL / min, and the concentration of the chelating agent NH 4 OH (aq) The flow rate of the precipitant was 0.5 mL / min. (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.2.

[0098] Finally, the solution containing the cathode material precursor having the core-shell structure was filtered, washed, and dried, and then mixed with a lithium source (lithium hydroxide) and ball-milled. The mixture was then calcined by introducing oxygen in a high-temperature tubular furnace to obtain a nickel-rich cathode oxide. The electrochemical properties of the nickel-rich cathode oxide were then measured.

[0099] <Comparative Example 1> Multimetallic solutions (i.e., NiSO 4 :CoSO 4 :MnSO 4 The aqueous solution was mixed with 10 ... (aq) and chelating agent NH 4 OH (aq) was further fed into the Taylor-Couette flow apparatus to carry out a coprecipitation reaction to form a solution containing nickel-cobalt-manganese ternary alloy hydroxide particles. Here, the reaction temperature of the Taylor-Couette flow apparatus was 60°C, the motor speed was 600 rpm, the average residence time of the material was 500 min, the flow rate of the feed material (multi-metal solution) was 1.5 mL / min, and the chelating agent NH 4The flow rate of OH(aq) was 0.5 mL / min, and the precipitant NaOH (aq) By controlling the flow rate of (concentration 4M), the pH value of the solution was controlled at pH=11.

[0100] Finally, the solution containing the nickel-cobalt-manganese ternary alloy hydroxide particles was filtered, washed, and dried, and then mixed with a lithium source (lithium hydroxide) and ball-milled. The mixture was then calcined by introducing oxygen in a high-temperature tubular furnace to obtain the nickel-rich cathode oxide of Comparative Example 1. The electrochemical properties of the nickel-rich cathode oxide were then measured.

[0101] The main difference between Comparative Example 1 and Examples 1 to 3 is that in Comparative Example 1, core particles were produced using only a single Taylor-Couette flow device, and no functional coating layer was formed on the core particles.

[0102] The preparation methods of the cathode oxides (ie, lithium battery cathode materials) of the above examples and comparative examples are described in detail below.

[0103] The cathode oxide was prepared by mixing the precursor and a lithium salt (LiOH H 2 O, 98%, Sigma-Aldrich) was reacted with LiNi 0.8 Co 0.1 Mn 0.1 X Z O 2 An oxide cathode material of NCM811 (also called NCM811, where X is a surface metal) was prepared, where the molar ratio of precursor to lithium salt (precursor:lithium salt) was 1:1.05.

[0104] The mixed material was then heated to 830°C in pure oxygen (O 2 ) atmosphere for 12 hours.

[0105] <Electrochemical measurements> In the electrochemical measurements of Examples 1 to 3 and Comparative Example 1, a positive electrode and a lithium metal negative electrode were assembled using a button-type CR2032 battery, and electrical measurements were performed.

[0106] First, the cathode formulation was prepared as an electrode slurry (containing the cathode active material, Super P conductive additive, and PVDF adhesive), and then processed through processes such as mixing, coating, drying, rolling, and cutting.

[0107] The fabricated cathode sheets were then assembled into CR2032 half-cells, followed by measurement and analysis of the electrochemical performance indicators (KPIs) of the composite materials, such as gram capacity, gram discharge capacity, Coulombic efficiency (CE%), and gram capacity retention (CR%).

[0108] The electrochemical measurement results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1 below.

[0109] [Table 1]

[0110] According to the experimental results in Table 1, the 100 charge / discharge cycle retention rates of Examples 1 to 3 showed excellent performance (i.e., 81.95% to 91.56% charge / discharge cycle retention rates). Furthermore, the cathode materials of Examples 1 to 3 had no significant cracks on the surface of the cathode materials after 500 charge / discharge cycles.

[0111] Regarding scanning electron microscope (SEM) analysis, Fig. 2A is an SEM photograph of a cathode material having a core-shell structure according to Example 3 of the present invention, and Fig. 2B is an SEM photograph of a core particle cathode material having only a single layer according to Comparative Example 1.

[0112] FIG. 3A is an SEM photograph of a cathode material having a core-shell structure according to Example 3 after 500 charge-discharge recycle measurements have been performed. FIG. 3B is an SEM photograph of a cathode material having a core-shell structure according to Comparative Example 1 after 500 charge-discharge recycle measurements have been performed. FIG. 4A is an SEM photograph of a cross section of the cathode material of FIG. 3A. FIG. 4B is an SEM photograph of a cross section of the cathode material of FIG. 3B. Here, in FIG. 3A and FIG. 4A, after 500 charge-discharge recycle measurements have been performed, there are no significant cracks on the surface of the cathode material having a core-shell structure. In FIG. 3B and FIG. 4B, after 500 charge-discharge recycle measurements have been performed, significant cracks have been observed on the surface of the cathode material having only a single layer of core particles.

[0113] [Advantageous Effects of the Embodiments] As an advantageous effect of the present invention, the method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to the present invention includes the steps of: supplying a first reaction solution, which is a multi-metal solution, to a first Taylor-Couette flow apparatus, and carrying out a co-precipitation reaction to obtain a first product stream including a plurality of core particles. a second Taylor-Couette reaction step of supplying the first product stream to a second Taylor-Couette flow device connected in series with the first Taylor-Couette flow device and supplying a second reaction solution, which is an aqueous coating material solution, to the second Taylor-Couette flow device, so that the second reaction solution forms a functional coating layer on the outer surfaces of the plurality of core particles, thereby forming a second product stream containing a plurality of cathode material precursors having a core-shell structure, the second product stream including the cathode material precursors having a core-shell structure, the aqueous coating material solution being an aqueous transition metal solution; and a purification step of purifying the second product stream to purify and separate the plurality of cathode material precursors having a core-shell structure from the second product stream. This technical feature can replace a traditional continuous stirring reactor and achieve the purpose of continuous production.

[0114] Here, the first Taylor-Couette flow apparatus is used to form core particles with uniform element distribution and dense structure by coprecipitation, while the second Taylor-Couette flow apparatus is used to form a cathode material precursor having a core-shell structure by performing a surface coating treatment on the core particles.

[0115] The present invention can continuously form a cathode material precursor having a core-shell structure, which can effectively improve the stability and durability of a lithium battery while simultaneously achieving the safety of the material.

[0116] The above disclosure is merely a preferred embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto. Therefore, all equivalent technical modifications made by utilizing the specification and drawings of the present invention are included in the scope of the claims of the present invention. [Explanation of symbols]

[0117] 1. The First Taylor-Couette Flow Apparatus 1a First Rotation Axis 1b First reaction chamber 11 First reaction liquid supply unit 12 First chelating agent supply unit 13 First precipitant supply unit 14 First Rotary Motor 15 First Pump Module 151,152,153,154 First pump injection unit 16 First pH value monitoring unit 2. Second Taylor-Couette flow apparatus 2a Second rotation axis 2b Second reaction chamber 21 Second reaction liquid supply unit 22 Second chelating agent supply unit 23 Second precipitant supply unit 24 Second Rotary Motor 25 Second Pump Module 251,252,253 Second pump injection unit 26 Second pH monitoring unit P1 First generation logistics P2 Second generation logistics

Claims

1. a first Taylor-Couette reaction step of supplying a first reaction solution, which is a multi-metal solution, to a first Taylor-Couette flow device and carrying out a co-precipitation reaction to form and continuously output a first product stream including a plurality of core particles; a second Taylor-Couette flow apparatus connected in series to the first Taylor-Couette flow apparatus, the first product stream is supplied to the second Taylor-Couette flow apparatus, and a second reaction liquid, which is a coating material aqueous solution, is supplied to the second Taylor-Couette flow apparatus, so that the second reaction liquid forms a functional coating layer on each of the outer surfaces of the plurality of core particles, thereby forming a second product stream including a cathode material precursor having a core-shell structure, and the coating material aqueous solution is a transition metal aqueous solution; and a purifying step of purifying and isolating a plurality of said core-shell structured cathode material precursors from said second product stream by purifying said second product stream.

2. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein the multi-metal solution comprises at least three or more of a nickel (Ni) compound, a cobalt (Co) compound, a manganese (Mn) compound, a magnesium (Mg) compound, and an aluminum (Al) compound, and the core particles are at least one selected from the group consisting of ternary alloy hydroxide core particles and quaternary alloy hydroxide core particles.

3. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein the aqueous transition metal solution is at least one selected from the group consisting of a zirconium ion solution, a tungsten ion solution, an aluminum ion solution, a zinc ion solution, a titanium ion solution, a molybdenum ion solution, and a tin ion solution.

4. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein a second reactant flow rate for supplying the second reactant to the second Taylor-Couette flow apparatus is 3% to 20% of a first reactant flow rate for supplying the first reactant to the first Taylor-Couette flow apparatus.

5. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein a first reactant flow rate for supplying the first reactant to the first Taylor-Couette flow apparatus is 0.5 mL / min to 3 mL / min, a second reactant flow rate for supplying the second reactant to the second Taylor-Couette flow apparatus is 0.05 mL / min to 0.30 mL / min, and the second reactant flow rate is 3% to 20% of the first reactant flow rate.

6. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein a first reaction temperature in the first Taylor-Couette flow apparatus is between 45° C. and 70° C., and a rotation speed of a first rotary motor of the first Taylor-Couette flow apparatus is between 500 rpm and 900 rpm.

7. 7. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 6, wherein a second reaction temperature in the second Taylor-Couette flow apparatus is between 45° C. and 70° C., and a rotation speed of a second rotary motor in the second Taylor-Couette flow apparatus is between 400 rpm and 800 rpm.

8. 2. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein the first Taylor-Couette reaction step comprises forming a reaction mixture by supplying a first chelating agent and a first precipitating agent to the first Taylor-Couette flow apparatus so as to mix with the first reaction liquid, and a first residence time of the reaction mixture in the first Taylor-Couette flow apparatus is 300 minutes to 600 minutes.

9. 9. The method of claim 8, wherein the second Taylor-Couette reaction step comprises forming a separate reaction mixture by supplying a second chelating agent and a second precipitating agent to the second Taylor-Couette flow apparatus to mix with the second reaction liquid, respectively, and a second residence time of the separate reaction mixture in the second Taylor-Couette flow apparatus is between 150 minutes and 500 minutes, and the second residence time is between 50% and 85% of the first residence time.

10. 10. The method for preparing a cathode material precursor using a Taylor-Couette flow apparatus according to claim 1, wherein in the cathode material precursor having a core-shell structure, the core particle has a core particle diameter of 4 μm to 12 μm, and the thickness of the functional coating layer is 1% to 20% of the core particle diameter of the core particle.

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