KR101564009B1 - Continuously preparing method for Ni-Co-Mn composite precursor using Couette-Taylor vortix reactor - Google Patents

Abstract

The present invention relates to a method for continuously producing Ni _x Co _y Mn _{1 -xy} (OH) ₂ , which is a nickel-cobalt-manganese composite precursor used as a cathode active material in combination with lithium in a nickel secondary battery, Preparation of Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor seeds via primary co-precipitation in an Eta Taylor reactor and addition of the precursor seeds and metal coprecipitates in a batch reactor with overflow, A precursor of Ni _x Co _y Mn _{1 -xy} (OH) ₂ of about 3 to 4 탆 in size with high uniformity and high sphericity and high crystallinity can be produced.

Description

[0001] The present invention relates to a method for continuously producing a nickel-cobalt-manganese composite precursor using a Cu-Te-Tay reactor,

The present invention relates to a process for producing Ni _x Co _y Mn _{1 -xy} (OH) ₂ which is a nickel-cobalt-manganese composite precursor which is mixed with lithium in a lithium secondary battery and used as a cathode active material, The present invention relates to a technique capable of producing a precursor of Ni _x Co _y Mn _{1 -xy} (OH) _{2 having} a uniform and spherical shape and having a small particle diameter through two co-processes using a dual structure of a reactor and a batch reactor.

Development of new secondary batteries such as a nickel hydride battery and a lithium secondary battery is progressing actively due to the spread of portable small electric and electronic devices. Among them, the lithium secondary battery uses carbon such as graphite as an anode active material, a metal oxide containing lithium as a cathode active material, and a non-aqueous solvent as an electrolyte. Lithium is a highly ionized metal, and is capable of high-voltage development, and is a source of energy for high energy density batteries.

Lithium transition metal oxides containing lithium are mainly used as the cathode active material used for the lithium secondary battery, and layered lithium transition metal complex oxides such as cobalt / nickel / ternary system (coexisting of cobalt, nickel and manganese) Have been used for more than 90%.

For example, Li ₂ CO ₃ and Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursors are mixed and calcined to be used as a cathode material. The particle size and the specific surface area of the Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor have a great influence on the high output power of a medium and large lithium battery for electric vehicles (HEV, PHEV, EV). Ni _x Co _y Mn _{1 -xy} (OH) _{2 As} the particle size of the anode material becomes smaller, the specific surface area increases and the diffusion distance of lithium ions becomes shorter, so that diffusion and entry of lithium ions can be smoothly and quickly performed. It is necessary to harden the precursor in order to maximize the specific surface area.

In general, the Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor is prepared by coprecipitation. After dissolving nickel salts, manganese salts and cobalt salts in distilled water, aqueous ammonia solution (chelating agent), aqueous NaOH solution ), The Ni _x Co _y Mn _{1 -xy} (OH) ₂ is synthesized and precipitated.

In the co-precipitation method, batch type reactors were mainly used. However, it was easy to manufacture uniform precursors by non-continuous coprecipitation using a batch type reactor, but due to the nature of the non-continuous type, There was a limit of ability. Of course, the batch type reactor could be continuously operated by overflow. In this case, the preparation of the precursor of the larger diameter was possible by controlling the reaction time (the residence time), but the precursor of the small diameter of 3 ~ There is a problem in that it is difficult to manufacture by the continuous method through the overflow of the overflow.

As another example of the continuous method, Patent Registration No. 10-1275845 discloses a technique for manufacturing a precursor for a cathode active material precursor for a lithium secondary battery using a quartetail reactor (see FIG. 1). As described above, the quat-tailer reactor can easily produce a precursor having a small particle size in a short time as compared with the case where the precursor is continuously produced through the overflow in a batch-type reactor. However, And the sphericity is lowered. Therefore, when it is used as a cathode material by mixing and firing with lithium, the electrical characteristics are poor.

Korean Patent Registration No. 10-1275845

The present invention, but an object of the present invention to provide a method for producing a _{Ni x Co y Mn 1 -xy (} OH) 2 precursor through a continuous process, in particular, the present invention is _{Ni x Co y Mn 1 -xy (} OH) 2 precursor (OH) ₂ precursor having a smaller particle size than that produced by coprecipitation in a conventional batch type reactor while maintaining a uniform morphology of the Ni _x Co _y Mn _{1 -xy} And a method thereof.

In order to achieve the above object, the present invention provides the following method.

The co-precipitate containing nickel, cobalt and manganese in a Quattro Taylor reactor is introduced and co-precipitated to form Ni _x Co _y Mn _{1 -xy} (OH) ₂ , A first coprecipitation step (1) of producing 0 <x <1, 0 <y <1, 0 <x + y <1) precursor seeds;

The coprecipitate containing nickel, cobalt and manganese together with the Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor seed discharged from the quattroyl reactor of the step (1) A second coprecipitation step (2) of producing Ni _x Co _y Mn _{1 -xy} (OH) ₂ by an immersion method; And

(3) of separating solid phase Ni _x Co _y Mn _{1 -xy} (OH) ₂ from the coprecipitate overflowed in the batch type reactor of said second coprecipitation step (2) The present invention provides a continuous process for producing Ni _x Co _y Mn _{1 -xy} (OH) ₂ using a reactor.

Particularly, it is preferable that the particle size of Ni _x Co _y Mn _{1 -xy} (OH) ₂ produced in the step (1) is 1 to 2 μm, and Ni _x Co _y Mn _{1 -xy} (OH ) &Lt; ₂ &gt; is 3 to 5 mu m.

In particular, the process conditions are preferably temperature and residence time in the reactor.

In particular, the coprecipitate of step (1) and step (2) is preferably a coprecipitate comprising nickel sulfate, cobalt sulfate and manganese sulfate.

In particular, it is preferable that the co-precipitate of step (1) further contains ammonia and sodium hydroxide.

The precursor of Ni _x Co _y Mn _{1 -xy} (OH) _{2 having} a small sphericity and a low degree of crystallinity and having a small particle size can be continuously produced through a conventional quat-tailer reactor. However, The precursor of Ni _x Co _y Mn _{1 -xy} (OH) ₂ can be continuously produced with a small particle size, high sphericity and a high degree of crystallinity through the double coprecipitation of the batch type reactor.

1 is a view for explaining an apparatus for producing a cathode active material precursor for a lithium secondary battery using a quartetailer reactor of Korean Patent Registration No. 10-1275845 as a prior art.
2 is a system diagram for implementing the method of the present invention.
Figs. 3A to 3D are experimental results of the precursor prepared in Example 1, wherein 3a and 3b are SEM measurement photographs with different magnifications, 3c is a particle size distribution chart, and 3d is an XRD measurement photograph.
Figs. 4A to 4D are experimental results of the precursor prepared in Example 2, wherein 4a and 4b are SEM measurement photographs with different magnifications, 4c is a particle size distribution chart, and 4d is an XRD measurement photograph.
FIGS. 5A to 5C are experimental results of the cathode active material for a lithium secondary battery manufactured by Example 3, wherein 5a and 5b are SEM measurement photographs with different magnifications, and 5c is a result of a charge / discharge test.

Hereinafter, the present invention will be described. In the following description, "precursor" means a Ni _x Co _y Mn _1-xy (OH) ₂ precursor, 0 < x < 1, 0 < y &lt;

The present invention relates to a process for the preparation of Ni _x Co _y Mn _{1 -xy} (OH) ₂ , wherein the coprecipitate containing nickel, cobalt and manganese is placed in a Quattro Taylor reactor, A first coprecipitation step (1) of producing 0 <x <1, 0 <y <1, 0 <x + y <1) precursor seeds; The coprecipitate containing nickel, cobalt and manganese together with the Ni _x Co _y Mn _1-xy (OH) ₂ precursor seeds discharged from the quattro Taylor reactor of the step (1) A second coprecipitation step (2) of producing Ni _x Co _y Mn _{1 -xy} (OH) ₂ by an immersion method; And (3) separating solid phase Ni _x Co _y Mn _{1 -xy} (OH) ₂ from the coprecipitate which overflows in the batch type reactor of the second co-seeding step (2) It provides a continuous manufacturing method of _{Ni x Co y Mn 1-xy} (OH) 2 using a Taylor reactor.

The present invention provides a process for preparing a Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor through a continuous process, wherein a first co-deposition through a quattro Taylor reactor and a first co- Ni _x Co _y Mn _{1 -xy} (OH) continuous Ni _x Co _y Mn _{1 -xy} through the co-precipitation of the secondary two-stage co-precipitation of the needle to the WIP and the _second precursor into the seed (seed) is prepared by (OH) ₂ &lt; / RTI &gt; precursor. The batch type reactor also feeds the coprecipitate and the Ni _x Co _y Mn _1-xy (OH) ₂ precursor seeds continuously, and the final reactants are also discharged to the outside through the overflow system, Respectively.

Hereinafter, each step will be described.

Quet  The first coprecipitation step (1) using the Taylor reactor,

The present invention produces a Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor seed in a Quattro Taylor reactor. The quat-tailer reactor may be a conventional quat-tailor reactor, and the quat-tailor reactor itself is a well-known technology, so a detailed description thereof will be omitted.

Due to the nature of the Quattro Taylor reactor, it is possible to produce Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor seeds continuously in a short time. Preferably, the Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor seeds produced in the quattro Taylor reactor have a size of 1 to 2 μm, preferably about 2 μm, .

A second coprecipitation step (2) using a batch type reactor,

A Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor of about 2 탆 produced in the first coprecipitation step (1) is used as a seed, and a Ni _x Co _y Mn _{1 -xy} OH) ₂ precursor. Of course, not only the size of the precursor particle is increased through the second coprecipitation, but also the degree of crystallization is increased, and the sphericity and uniformity are increased.

In the second coprecipitation step, the precursor seed of Ni _x Co _y Mn _{1 -xy} (OH) ₂ produced in the first coprecipitation step is _mixed with the precursor of nickel, cobalt and manganese introduced into the batch type reactor, And will proceed with the co-ordination. In the second coprecipitation step, particles are grown using the Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor prepared in the quartet-Taylor reactor as a seed. For example, in the second coprecipitation step (2), the precursor seed having a size of 2 탆 produced in the first coprecipitation step (1) is made of a precursor of Ni _x Co _y Mn _{1 -xy} (OH) _{2 having a} size of 3 to 4 탆 do. The batch type reactor was overflowed to allow continuous processing. The overflowed coprecipitate contains a pre-reacted Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor and an unreacted coprecipitate to separate the solid Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor A step is required.

Ni _x Co _y Mn _{One -x-y} ( OH ) ₂ Precursor Separation Step (3)

Since the reacted Ni _x Co _y Mn _1-xy (OH) ₂ precursor is contained in the coprecipitate in the batch type reactor, the solid phase Ni _x Co _y Mn _{1 -xy} (OH) ₂ It is necessary to separate only the precursor. Such separation may be carried out by simple precipitation or a method for separating solid fine particles from various conventional liquids such as sieves. The size of the finally produced Ni _x Co _y Mn _{1 -xy} (OH) ₂ precursor can preferably be about 3 to 4 μm.

The precursor prepared by the method of the present invention is small-sized and thus has a large specific surface area and high sphericity and is used as a cathode element to exhibit high output characteristics.

[ Example ]

[ Example  1] First Coalition: Quet  Using a Taylor reactor Ni _x Co _y Mn _{One -x-y} ( OH ) ₂ Manufacture of precursor seed

The following were prepared in a _{Ni x Co y Mn 1 -xy (} OH) 2 x = 0.8, y = 0.1 of _{Ni 0 .8 Co 0 .1 Mn 0} .1 (OH) 2. This can be accomplished by controlling the molar ratio of nickel sulfate, cobalt sulfate and manganese sulfate to produce precursors of the above formula.

Nickel sulfate, cobalt sulfate, and manganese sulfate were mixed in a molar ratio of 0.8: 0.1: 0.1 to prepare two 5 L metal aqueous solutions of 2.5 M, and a solution prepared by mixing 5 to 7% of NH ₄ OH and 12 to 15% of NaOH 5L were prepared. The 1 L Kuett-Taylor reactor was filled with deionized water (DI water) and heated to 50-60 ° C using a temperature holding device.

The NH ₄ OH and NaOH mixed solution prepared in the reactor 7 ~ 9 mL / to the metering pump min were subsequently added, the prepared metal solution using a metering pump 4 ~ 7 mL / min in N ₂ gas 2 L / min . The stirring rpm of the reactor was fixed at 800 to 900, and the reaction product of the seeds prepared by using the overflow was connected to the rear batch reactor.

[ Example  2] Second Co-op: Batch type  Through the reactor Ni _x Co _y Mn _{One -x-y} ( OH ) ₂ Precursor manufacture

The conventional water tank reactor is a 5L double water tank reactor, which is a general vortex system equipped with a baffle and a stirrer. The existing reactor was filled with 2 L of distilled water, and the temperature was previously raised to 50 to 60 ° C using a temperature holding device. An overflow was also installed in this reactor and the stirring rpm was fixed at 800-1000.

Ku eth- given by the overflowed seed role in Taylor reactor _{Ni 0 .8 Co 0 .1 Mn 0} .1 (OH) ₂ In a state where the maintaining stirring to 4L are filled in the batch reactor. At the time when 4L was filled, a metal aqueous solution (2.5M concentration of nickel sulfate, cobalt sulfate and manganese sulfate mixed solution) prepared by a batch type reactor was mixed with 3 L / min of N ₂ gas at 7 to 9 mL / min using a metering pump Lt; / RTI &gt; No separate pH control was applied.

Only the precursor Ni _0.8 Co _0.1 Mn _0.1 (OH) ₂ which is solid in the reactant overflowing in the batch type reactor is separated The hot water washing was repeated several times by a filtering method and then dried in a constant temperature drier at 120 캜 for 20 hours to obtain a nickel-cobalt-manganese ternary precursor.

[ Example  3] Lithium mixed cathode active material manufacturing

Ni ₀ manufactured by LiOH as Example _{2 .8 Co 0 .1 Mn 0 .1} (OH) formula Li [Ni to the _second precursor calcined at 800 ℃ for 20 h _{0 .8} Co _{0 .1} Mn _{0 .1} ] O &lt; _{2 &} gt ;.

[ Experimental Example ]

The following results were obtained for each of the products produced by Examples 1 to 3 above.

[ Experimental Example  One] Quet  The Ni after the first coprecipitation prepared in the Taylor reactor _0.8 Co _0.1 Mn _0.1 (OH) ₂ Experiment of precursors

Figures 3a and 3b is a _{Ni 0 .8 Co 0 .1 Mn 0} .1 SEM photo by measuring the contrast ratio of (OH) ₂ precursor made from Et-ku Taylor reactor manufactured by the first embodiment. As shown in SEM photos of Figs. 3a and _{3b, Ni 0 .8 Co 0 .1} Mn 0 .1 (OH) ₂ is made by first co-precipitation was confirmed that the circularity is not good. Figure 3c was found to be a particle size distribution of the Ni _{0 .8} Co _{.1 0 .1 0} Mn (OH) ₂ precursor prepared by Example 1, the median size is 1.953㎛.

FIG. 3D is an XRD measurement photograph of the Ni _{0 .8} Co _{0 .1} Mn _{0 .1} (OH) ₂ precursor prepared by Example 1, in which the peaks were not clear and the peaks were broadly measured, From this XRD result, it can be seen that the Ni _0.8 Co _0.1 Mn _0.1 (OH) ₂ precursor produced by the first coprecipitation with the Cuat Taylor reactor is amorphous.

From the results shown in FIGS. 3A to 3C, it was confirmed that the precursor produced in the Kuett Taylor reactor had a low sphericity and was made amorphous, and thus was not suitable as a cathode active material.

[ Experimental Example  2] Batch type  After the second coprecipitation produced in the reactor Ni _{0 .8} Co _{0 .One} Mn _{0 .One} ( OH ) ₂ Experiment of precursors

Figures 4a and 4b is a SEM photograph measured varying the magnification factor of the Ni _{0 .8} Co _{.1 0 .1 0} Mn (OH) ₂ precursor prepared by Example 2. As shown in FIGS. 4A and 4B, it was found that the sphericity of Ni _0.8 Co _0.1 Mn _0.1 (OH) ₂ produced by the second coprecipitation was greatly improved.

Figure 4c was found that a particle size distribution of the Ni _{0 .8} Co _{.1 0 .1 0} Mn (OH) ₂ produced by a precursor to the second embodiment, a median size 3.735㎛. That is, a size of 1.953 ㎛ by the primary co-precipitated Ni _{0 .8} Co _{.1 0 .1 0} Mn (OH) ₂ precursor seeded, grown by a secondary co-precipitation was grown to 3.735 ㎛.

Figure 4d is a second embodiment of _{Ni 0 .8 Co 0 .1 Mn 0} .1 (OH) ₂ precursor XRD measurement picture produced by, were also the peak measured distinctly compared to 3d, which by the Taylor reactor ku Et _{0 .8} Co _{.1 0} is the Ni Mn _{0 .1} (OH) _second precursor prepared by the coprecipitation 1 means that the degree of crystallinity increased after the second co-precipitation.

That is, by the second co-precipitated _{Ni 0 .8 Co 0 .1 Mn 0} .1 (OH) to check that the sphericity and crystallinity of the _precursor increased, manufactured through a double co-precipitation according to the invention through which Ni _.8 Co _{.1 0 .1 0 0} Mn (OH) ₂ precursor was found that having a structure suitable as a cathode active material.

[ Experimental Example  3] Physical properties of lithium mixed cathode active material

Experimental Example 3 is an experimental result of Li [Ni _0.8 Co _0.1 Mn _0.1 ] O _{2 which} is a lithium mixed cathode element manufactured by Embodiment 3.

FIG. 5A and FIG. 5B are SEM photographs taken at different magnifications, and it was found that the shape of a typical Li [Ni _{0 .8} Co _{0 .1} Mn _{0 .1} ] O ₂ cathode material was observed. FIG. 5C shows a result of a charge / discharge test using a coin cell, showing an electrical characteristic of an output efficiency (2C / 0.1C) of 0.8374 and an initial capacity of 162.4.

Claims (5)

The co-precipitation of nickel, cobalt and manganese in a quartz-tailor reactor is introduced and co-precipitation is performed to produce Ni _x Co _y Mn _1-xy (OH) ₂ , A first coprecipitation step (1) of producing 0 <x <1, 0 <y <1, 0 <x + y <1) precursor seeds;
In step (1), a mixed precursor of Ni _x Co _y Mn _1-xy (OH) ₂ precursor seeds discharged from the quattro Taylor reactor is continuously fed into a reactor of a batch type, A second coprecipitation step (2) of producing Ni _x Co _y Mn _1-xy (OH) ₂ by a second coprecipitation step (2); And
(3) separating solid phase Ni _x Co _y Mn _1-xy (OH) ₂ from the coprecipitate overflowed in a batch type reactor in said second coprecipitation step (2)
Wherein the Ni _x Co _y Mn _1-xy (OH) ₂ particles prepared in the step (1) have a particle size of 1 to 2 μm and the Ni _x Co _y Mn _1-xy (OH) ₂ Wherein the temperature or the residence time in the reactor is controlled so that the particle size of the Ni _x Co _y Mn _1-xy (OH) ₂ is from 3 to 5 μm.
delete delete In claim 1, wherein the ball immersion in the above step (1) and (2) Ni _x Co _y Mn _1- using a Pico eth- Taylor reactor, characterized in that the immersion ball containing nickel sulfate, cobalt sulfate and manganese sulfate _xy (OH) ₂ .
In claim 1, wherein the continuous method of producing a _{Ni x Co y Mn 1 -xy (} OH) 2 using a Pico eth- Taylor reactor, it characterized in that the immersion of the ball of the step (1) further includes an ammonia and sodium hydroxide.

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