WO2012011760A2 - Method for manufacturing anode active material precursor in lithium secondary battery, anode active material precursor in lithium secondary battery manufactured thereby, and method for preparing lithium metal composite oxide using the anode active material precursor and lithium metal composite oxide for anode active material in lithium secondary battery prepared thereby - Google Patents

Abstract

The present invention provides a method for manufacturing a anode active material precursor in a lithium secondary battery, comprising the following steps: (a) preparing a nickel cobalt composite oxide by coprecipitation by mixing with a solution a mixed metal solution, which comprises compounds including nickel and compounds including cobalt, an ammonia aqueous solution as a complexing agent, and an alkaline aqueous solution which provides a hydroxyl group as a pH controlling agent; (b) introducing a metal element M to the nickel cobalt composite oxide prepared from the step (a), wherein the anode active material precursor in the lithium secondary battery is represented by Chemical Formula 1 below, and wherein the lithium metal composite oxide for the anode active material in the lithium secondary battery is represented by Chemical Formula 2 below. [Chemical Formula 1] [Ni_1-y-zCo_yM_z](OH)₂ (where in the Chemical Formula 1, M is a group 13 metal element and is one or a combination of two or more elements selected from a group consisting of B, Al, Ga, In, and Tl, and 0≤y≤0.25, 0≤z≤0.15). [Chemical Formula 2] Li_x[Ni_{1 -y- z}Co_yM_z]O₂ (where in the Chemical Formula 2, M is group 13 metal element and is one or a combination of two or more elements selected from a group consisting of B, Al, Ga, In, and Tl, and 0.96≤x≤1.05, 0≤y≤0.25, 0≤z≤0.15).

Description

Method for producing a lithium secondary battery positive electrode active material precursor, a lithium secondary battery positive electrode active material precursor produced thereby, and. Method for producing a lithium metal composite oxide for a lithium secondary battery cathode active material using the cathode active material precursor, Lithium metal composite oxide for a lithium secondary battery cathode active material produced thereby.

The present invention is a method for producing a lithium secondary battery positive electrode active material precursor, a lithium secondary battery positive electrode active material precursor prepared by this, and a method for producing a lithium metal composite oxide for a lithium secondary battery positive electrode active material using the positive electrode active material precursor, thereby The present invention relates to a lithium metal composite oxide for a lithium secondary battery cathode active material.

In recent years, miniaturization, light weight, and high performance of portable electronic devices such as video cameras, portable CDs, cellular phones, PDAs, and notebook computers are progressing. There is a need for a secondary battery having high capacity and high stability for power of portable electronic devices. Nickel cadmium accumulators have been used as secondary batteries consistent with this purpose. Lithium secondary batteries have been put into practical use as nickel-hydrogen accumulators and nonaqueous electrolyte secondary batteries as batteries having higher energy density.

Commercially available small lithium secondary batteries generally use LiCoO ₂ for the positive electrode and carbon for the negative electrode. LiCoO ₂ is an excellent material having stable charge and discharge characteristics, excellent electronic conductivity, high stability, and flat discharge voltage characteristics. However, Co has low reserves, is expensive, and toxic to humans. LiNiO ₂ having a layered structure such as LiCoO ₂ exhibits a large discharge capacity but has not been commercialized due to problems in cycle life, thermal instability, and safety at high temperatures.

Many improvements have been made to address this problem, such as LiNi _x Co _1-x O ₂ (x = 1,2) or LiNi _1-xy Co _x Mn _y O ₂ (0≤x≤0.5, 0≤y≤0.5). A positive electrode active material of the composition has been attempted but not satisfactory enough to solve the problems mentioned above.

Doping a small amount of stable Group 13 metals such as B, Al, In, and Tl to LiNi _x Co _1-x O ₂ may improve structural instability. This is because a stable trivalent metal ion such as Al stabilizes the hexagonal structure as it moves or disperses between NiO ₂ layers during charge and discharge. Li _x [Ni _1-yz Co _y Al _z ] O ₂ (0.96 ≦ x ≦ 1.05, 0 ≦ _y ≦ 0.2, 0 ≦ _z ≦ 0.1) and (hereinafter NCA) having such composition and structure have high thermal stability and high It has cycle life, high discharge voltage by cobalt, and stability of layered structure by aluminum. NCA has the highest capacity among the cathode active materials for lithium secondary batteries currently on the market.

However, despite these performance reasons and the cost advantage of low cobalt metal content, NCA is expensive due to high process costs and difficult to synthesize, which limits the rapid increase in production and demand.

As described above, NCA not only partially substitutes cobalt, another transition metal, in the nickel site at the exact position of LiNiO ₂ , which is a layered high-capacity cathode active material, but also has Ni +2 + or + 4-valent ions. It is a cathode active material doped with aluminum, which is a Group 13 metal having stable + trivalent ions to prevent oxidation and to provide structural stability. In the NCA manufacturing method using the coprecipitation method, the pH range for forming hydroxides of the metals is a very important factor for obtaining uniform particles of the metal complex hydroxide to be co-precipitated.

However, the pH reaction zone in which the metal hydroxides of nickel (Ni) and cobalt (Co), which are main components, are well formed is a strong basic region (pH> 10), and the pH reaction zone in which the metal hydroxide of aluminum doped for structural stability is well formed. If the silver is in the neutral region (pH 7-9), and the reaction occurs in the strong basic solution of pH 11-12, which is the co-precipitation region of nickel and cobalt as the main component in the coprecipitation reaction of the metal complex hydroxide containing nickel cobalt aluminum, As with other metals, it is difficult to form a complex hydroxide, and even a small amount is coprecipitated, and most of them are dissolved in a solution in the form of Al ³⁺ ions. In order to improve the coprecipitation of aluminum, if the coprecipitation reaction pH is lowered and the reaction time is longer than 2 times, the aluminum coprecipitation works well, but the coprecipitation efficiency with nickel and cobalt metal hydroxide decreases. In other words, in order to stably manufacture the metal complex hydroxide, an excessive amount of the metal composite material should be added, and as a result, the loss of the introduced metal has to be taken as a result, which has a disadvantage in that the yield and productivity in the manufacturing process decrease.

In order to solve the above problems, the process is simple and the process cost is improved by reducing lead time and increasing process yield through the post-introduction of dissimilar metals rather than simultaneous co-precipitation of composite metals. It is an object of the present invention to provide a method for preparing an active material precursor, a cathode active material prepared thereby, a method for producing a lithium metal composite oxide for a cathode active material using the cathode active material precursor, and a lithium metal composite oxide prepared thereby.

Method for producing a lithium secondary battery positive electrode active material precursor of the present invention for solving the above object

(a) preparing a nickel cobalt complex hydroxide by coprecipitation by mixing a metal mixture solution containing a nickel-containing compound and a cobalt-containing compound, an aqueous ammonia solution as a complexing agent, and an alkaline aqueous solution providing a hydroxyl group as a pH adjusting agent with a solvent;

(b) introducing a metal element M into the nickel cobalt composite hydroxide obtained in step (a); and the lithium secondary battery cathode active material precursor prepared by the preparation method is represented by the following [Formula 1] .

[Chemical Formula _{1] [Ni 1 -y- z Co} y M z] (OH) 2

(In Formula 1, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, and 0≤y≤0.25, 0≤z≤0.15)

In the present invention, the concentration of metal ions in the metal mixture solution containing the nickel-containing compound and cobalt-containing compound of step (a) is 1 to 3M, the mixing ratio of the metal and the complexing agent is 1: 0.1 to 2.5 The reactor internal temperature is 30 to 60 ℃, pH is characterized in that the stirring at 200 to 1000 rpm while maintaining a 10 to 13.

In the present invention, in the step of introducing the metal element M to the nickel cobalt composite hydroxide of the step (b), the nickel cobalt composite hydroxide obtained in the step (a), a solution containing a metal element M and a coprecipitation agent is mixed A method of manufacturing a secondary battery cathode active material precursor, a lithium secondary battery cathode active material precursor prepared thereby, a method of manufacturing a lithium metal composite oxide for a lithium secondary battery cathode active material using the cathode active material precursor and a lithium secondary battery cathode active material produced thereby The lithium metal composite oxide particles are prepared, and the resulting particles are washed and dried.

In the present invention, the solution containing the metal element M is an aqueous metal salt solution or metal acid containing the metal element M, and the coprecipitation agent is a base or an acidic solution.

The present invention also provides a lithium secondary battery cathode active material precursor prepared by the method for producing a lithium secondary battery cathode active material precursor of the present invention.

In addition, the manufacturing method of the lithium metal composite oxide for a lithium secondary battery positive electrode active material according to another embodiment of the present invention

       (i) preparing a lithium metal composite hydroxide by mixing a lithium secondary battery cathode active material precursor prepared by the manufacturing method and a lithium compound; And

(ii) calcining the lithium metal composite hydroxide to obtain a lithium metal composite oxide; and the compound prepared by the preparation method is represented by the following [Formula 2].

Li _x [Ni _{1 -y- z} Co _y M _z ] O ₂

(In Formula 2, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, 0.96≤x≤1.05, 0≤y≤0.25, 0≤z≤0.15 being)

In the present invention, in step (i), the lithium secondary battery cathode active material precursor prepared by the manufacturing method and the lithium compound are mixed in a ratio of 1: 0.96 to 1: 1.05, and in step (ii), 650 under an oxygen atmosphere. To 850 ° C.

The present invention also provides a lithium metal composite oxide prepared by the method for producing a lithium metal composite oxide of the present invention.

According to the present invention, it is possible to manufacture a large amount of low-cost lithium metal composite oxide for a lithium secondary battery cathode active material having a simple process and low process cost by reducing a lead time and increasing a process yield. The composite oxide has a small amount of fine powder and high uniformity, which enables high capacity and high performance of the cathode active material.

1 is an XRD graph according to an embodiment of the present invention.

2 to 4 are 5,000 times the SEM photograph of the lithium metal composite oxide according to an embodiment of the present invention.

5 and 6 are 5,000 times the SEM photograph of the lithium metal composite oxide according to the comparative example of the present invention.

7 is a 5,000 times SEM photograph of the metal composite hydroxide synthesized in a continuous reactor according to an embodiment of the present invention.

8 is a 5,000 times SEM photograph of the metal complex hydroxide synthesized in a batch reactor according to an embodiment of the present invention.

9 is a 5,000 times SEM photograph of the metal composite hydroxide synthesized by the co-precipitation method according to a comparative example of the present invention.

10 to 12 are graphs of EDS measurement data for (a) SEM photographs of particle cross sections and (b) EDS intensity ratios by metal elements, and (c) molar ratios by metal elements according to one embodiment of the present invention.

13 is a graph of the initial capacity of the battery using a positive electrode active material according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

The present invention provides a method for preparing a cathode active material precursor, which is a prior material of a cathode active material, and provides a method for finally obtaining a cathode active material by reacting a precursor prepared by this method.

First, the method for preparing a lithium secondary battery positive electrode active material precursor of the present invention comprises (a) a metal mixed solution containing a nickel-containing compound and a cobalt-containing compound, an aqueous ammonia solution as a complexing agent, and an alkaline aqueous solution providing a hydroxyl group as a pH adjusting agent. Mixing to prepare nickel cobalt composite hydroxide by a coprecipitation method; (b) introducing the metal element M into the nickel cobalt composite hydroxide obtained in step (a), and the prepared nickel cobalt metal composite hydroxide is represented by the following [Formula 1].

[Chemical Formula _{1] [Ni 1 -y- z Co} y M z] (OH) 2

(In Formula 1, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, and 0≤y≤0.25, 0≤z≤0.15)

In the step (a), a co-precipitation method is performed by mixing a metal mixed solution containing a nickel-containing compound and a cobalt-containing compound, an aqueous ammonia solution as a complexing agent, and an alkaline aqueous solution providing a hydroxyl group as a pH adjusting agent with a solvent. precipitation method) to prepare nickel cobalt composite hydroxide.

The coprecipitation method is a method in which different ions are precipitated simultaneously in an aqueous solution or a non-aqueous solution. The nickel cobalt mixed metal reacts with the nickel cobalt mixed metal, a complexing agent, and a precipitant continuously supplied to the reactor, and the metal complex hydroxide Ni _a Co _{It is} to prepare _b (OH) ₂ .

In the nickel-containing compounds and cobalt-containing compounds, anions of the nickel and cobalt metal salt is a sulfate (SO ₄ ^-2), nitrate (NO ₃ ^-) and the like can be used, hydrochloride (Cl ^{- -)} and nitrate (COO).

The concentration of metal ions in the metal mixture solution containing the nickel-containing compound and the cobalt-containing compound is preferably 1 to 3M. If the concentration of metal ion is less than 1M, the productivity is poor due to the small amount of material produced. If the concentration of metal ion is more than 3M, the metal salt may precipitate in the storage tank or the input pipe, so it must be heated to a high temperature. This is because the concentration of is difficult to control the co-precipitated particles because the reaction can proceed quickly.

Even when using a metal mixture solution of 1 ~ 3M it is preferable to maintain a constant temperature of the metal solution reservoir and pipe at 40 ~ 50 ℃. Maintaining the temperature in the above range is less influenced by the external temperature to prevent the precipitation of metal in the cold winter, as well as to make the viscosity of the metal mixture solution constant so that the amount of the metal mixture solution to be added is kept more constant. To stabilize the reactor.

The complexing agents generally include ammonia water (NH ₄ OH), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), ammonium nitrate (NH ₄ NO ₃ ), and first ammonium phosphate ((NH ₄ ) ₂ HPO ₄ ). It can be used, Preferably ammonia water is used. Ammonia generated in the complexing agent serves to control the shape of the metal complex hydroxide formed.

The pH adjusting agent may be an aqueous alkali solution such as lithium hydroxide (LiOH), sodium hydroxide (NaOH) and potassium hydroxide (KOH). The pH adjusting agent serves as a precipitating agent, and serves to maintain a pH suitable for coprecipitation in the mixed aqueous solution.

The mixing ratio of the metal and the complexing agent in the metal mixture solution is 1: 0.1 to 2.5, the reactor internal temperature is preferably maintained at 30 to 60 ℃, more preferably 45 to 55 ℃. It is preferable to stir at 200 to 1000 rpm for 5 to 20 hours while maintaining the pH at 10 to 13.

At this time, the reactor can use a volume of 1 ~ 1,000L, preferably characterized by using a reactor of 50 ~ 500L. In addition, the reactor used in the present invention may use a continuous reactor (CSTR, Continuous Stirring Tank Reactor) and a batch type (Batch Type Tank Reactor), respectively. Continuous reactors have the advantage of productivity, and batch reactors have the advantage of no reactor stabilization time and free form exchange.

When the co-precipitation product is initially extracted after the co-precipitation reaction, nickel cobalt composite hydroxide, which is a spherical secondary particle in which fine primary particles are aggregated, is formed. When the Group 13 metal element M is introduced to the nickel cobalt composite hydroxide thus prepared in the next step, the mass production is possible because the Group 13 element can produce more than twice the yield and yield 95% or more than the composite hydroxide co-precipitated simultaneously. Has the advantage of

Then, step (b) is a step of introducing a metal element M into the nickel cobalt composite hydroxide obtained in the step (a), a wet manufacturing method is used. The nickel cobalt composite hydroxide particles obtained in step (a) and a solution containing a metal element M and a coprecipitation are mixed to produce nickel cobalt composite hydroxide particles, and the resulting nickel cobalt composite hydroxide particles are washed and dried. There are two methods of the wet manufacturing method: a metal salt as a metal raw material, a basic solution as a coprecipitation agent, and a metal acid as a metal raw material and an acidic solution as a coprecipitation agent.

The metal element M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more thereof. The solution containing the metal element M is an aqueous metal salt solution or metal acid containing the metal element M. When the solution containing the metal element M is an aqueous metal salt solution, the coprecipitation agent is a basic solution, and when the solution containing the metal element M is a metal acid, the coprecipitation agent is an acid solution.

When aluminum (Al) is selected among the metal elements M, aluminum raw materials used are aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum nitrate Al (NO ₃ ) ₃ , aluminum chloride (AlCl ₃ ) and aluminum acetate ( Aluminum metal salts such as Al (COO) ₃ ) and metal acids such as sodium aluminate (NaAlO ₂ ) can be used. The concentration of the metal raw material solution is preferably 1 to 3M.

In the wet manufacturing method 1 described above, a metal salt is used as a metal raw material, and the coprecipitation agent is lithium hydroxide (LiOH), which functions to maintain a pH suitable for coprecipitation in the mixed aqueous solution as a pH adjusting agent using an alkaline solution, Sodium hydroxide (NaOH), potassium hydroxide (KOH) and the like can be used. The pH range of the reaction is preferably 8 to 12, more preferably 9 to 11.5. If the pH is higher than 11.5, the aluminum hydroxide is difficult to co-precipitate. If the pH is lower than 9, the coagulation phenomenon of nickel cobalt metal mixed hydroxide occurs, which makes it difficult to control the desired particle size.

Wet manufacturing method 2 is a case in which a metal acid is used as a metal raw material, and the coprecipitation agent adjusts the pH using an acid solution and maintains a suitable pH for coprecipitation to occur, such as sulfuric acid (H ₂ SO ₄ ) and nitric acid (HNO ₃ ). Hydrochloric acid (HCl), phosphoric acid (H ₃ PO ₄ ), acetic acid (CH ₃ COOH), and the like, and the pH is preferably in the range of 6-9.

In all wet manufacturing methods, the materials in the reactor are reacted with stirring at a speed of 200 to 1000 rpm, and the reaction time is preferably synthesized at 30 minutes to 10 hours to prepare a slurry.

The slurry formed by the wet manufacturing method is filtered and washed with high purity distilled water, and then dried in a vacuum oven at 100 to 130 ° C. for 10 to 15 hours to obtain nickel cobalt metal complex hydroxide. The nickel cobalt metal composite hydroxide thus obtained is spherical secondary particles in which fine primary particles are aggregated.

A lithium metal composite oxide for a cathode active material is prepared by using the cathode active material precursor prepared by the method for preparing a lithium secondary battery cathode active material precursor described above.

The method for producing a lithium metal composite oxide for a positive electrode active material includes (i) mixing a lithium secondary battery positive electrode active material precursor prepared by the above-described manufacturing method and a lithium compound to prepare a lithium metal composite hydroxide, and (ii) the lithium metal Calcining the composite hydroxide to obtain a lithium metal composite oxide; wherein the prepared lithium metal composite oxide is represented by the following [Formula 2].

Li _x [Ni _{1 -y- z} Co _y M _z ] O ₂

(In Formula 2, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, 0.96≤x≤1.05, 0≤y≤0.25, 0≤z≤0.15 being)

First, in step (i), the obtained dried metal complex hydroxide is heat-treated at 400 to 600 ° C. for 6 to 15 hours to obtain nickel cobalt metal complex hydroxide doped with metal element M. To this mixture with the lithium compound to the lithium source role, the lithium compound, lithium hydroxide (LiOH), lithium nitrate (LiNO ₃₎ and the like, but lithium carbonate (LiCO _3), it is not limited thereto. As can be seen in the formula (2), in the step (i) it is preferable to mix the lithium secondary battery cathode active material precursor prepared before and the lithium compound in a ratio of 1: 0.96 to 1: 1.05. If the x value in the formula (2) is less than 0.96, the capacity of the final positive electrode active material is lowered, which is not preferable. If the value exceeds 1.05, unreacted LiOH is formed and the capacity is lowered.

Then (ii) in the step of calcining the lithium metal complex hydroxide to obtain a lithium metal complex oxide, the lithium metal complex hydroxide obtained in the step (i) is calcined at 650 to 850 ℃ in an oxygen atmosphere to the desired lithium metal of formula (2) A composite oxide can be obtained.

In the present invention described above, unlike the simultaneous co-precipitation method of dissimilar metal elements such as nickel, cobalt and aluminum, a method of producing a doping hetero-metal element M after doping after the co-precipitation reaction of nickel and cobalt as main elements By using this method, the lead time can be reduced by more than 2 times and the process yield can be significantly increased to 95% or more. Therefore, a large amount of low-cost metal composite oxide for lithium secondary battery cathode active material can be manufactured.

The present invention is described in more detail through the following implementation. However, the examples are provided to illustrate the present invention, and the scope of the present invention is not limited only to these examples.

<Example 1>

Example 1.1 Synthesis of Nickel Cobalt Composite Hydroxide-Continuous Synthesis

A 2.0 M nickel sulfate hexahydrate (NiSO ₄ .6H ₂ O) and cobalt sulfate heptahydrate (CoSO ₄ · 7H ₂ O) metal mixed solution was prepared such that the Ni: Co molar ratio was 84.5: 15.5. In addition, 28% ammonia water as the complexing agent and 25% sodium hydroxide solution as the pH adjuster were used. A continuous reactor with a volume of 90 L filled with 1M aqueous ammonia solution was used and the pH of the initial solution was in the range of 11-12. The prepared 2.0 M nickel cobalt metal mixture solution, 28% aqueous ammonia and 25% sodium hydroxide solution was continuously added at the same time using a metering pump while stirring at a speed of 600 rpm. At this time, the temperature in the reactor was maintained at 50 ° C while the metal mixture solution was added at a rate of 7 L / hr and ammonia water at 0.5 L / hr. Sodium hydroxide was continuously reacted while adjusting the input amount to maintain the pH in the reactor at 11-12. Was performed. The reactor residence time was 8 hours. Slurry, a reaction product discharged through the reactor overflow in a continuous reaction, was collected.

Example 1.2 Introduction of Aluminum—Metal Salt Salt Solution and Basic Solution

Thereafter, the slurry produced in the batch type reactor having a volume of 90 L was collected at 90%, the temperature was maintained at 50 ° C., and the rotational speed was 600 rpm while the molar ratio of aluminum and the nickel cobalt metal mixture solution was 5 mol%. A 2.0 M aqueous aluminum nitrate (Al (NO ₃ ) ₃ ) solution and a 25% sodium hydroxide solution as co-precipitation were added at the same time. At this time, the addition rate of the aluminum nitrate solution was 2L / hr and sodium hydroxide was reacted for 1 hour while adjusting the input amount to maintain the pH in the reactor 10 ~ 11.5. The slurry solution in the reactor was filtered and washed with distilled water of high purity, and dried in a vacuum oven at 110 ℃ for 12 hours to obtain a nickel cobalt aluminum metal complex hydroxide. The composition of the obtained nickel cobalt aluminum metal composite hydroxide was Ni _0.8 Co _0.15 Al _0.05 (OH) ₂ .

Example 1.3 Preparation of Cathode Active Material

The dried nickel cobalt aluminum metal composite hydroxide was heat-treated at 550 ° C. for 6 hours in an air atmosphere to obtain a metal composite oxide, and lithium hydroxide (LiOH · H ₂ O) = Li / (Ni + Co + Al) = The mixture was mixed at a molar ratio of 1.03 to a Cordilite crucible (Sega) and calcined at 750 ° C. for 20 hours in an oxygen atmosphere. The composition of the calcined lithium metal composite oxide was Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ , and the total yield was 97.2%.

<Example 2>

Example 2.1 Synthesis of Nickel Cobalt Composite Hydroxide-Batch Synthesis

A 2.0 M nickel / cobalt mixed metal solution, 28% aqueous ammonia and 25% sodium hydroxide solution, prepared in the same manner as in Example 1.1, was continuously added to a batch reactor using a metering pump while stirring at a speed of 600 rpm. At this time, while maintaining the temperature in the reactor 50 ℃ mixed metal solution 6L / hr, ammonia water was added at a rate of 0.4L / hr, sodium hydroxide 3.0 ~ 4.0L / hr to maintain a pH of 11 ~ 12 in the reactor The dose was adjusted at speed.

The 90L batch type reactor was filled with 19% 1M aqueous ammonia solution and the temperature was maintained at 50 ° C. The pH of the initial solution ranges from 11-12. After 8 hours, 90% of the reactor volume was filled with a slurry containing nickel cobalt metal hydroxide, and the input of the raw material solution was stopped.

Example 2.2 Introduction of Aluminum—Metal Salt Salt Solution and Basic Solution

It proceeded in the same manner as in Example 1.2. The composition of the obtained nickel cobalt aluminum metal composite hydroxide was Ni _0.8 Co _0.15 Al _0.05 (OH) ₂ .

Example 2.3 Preparation of Positive Electrode Active Material

It proceeded in the same manner as in Example 1.3. As a result, a lithium metal composite oxide Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ was prepared in a yield of 96.1%.

<Example 3>

Example 3.1 Synthesis of Nickel Cobalt Composite Hydroxide-Continuous Synthesis

It proceeded in the same manner as in Example 1.1.

Example 3.2 Introduction of Aluminum—Metal Acid and Acid Solution

Fill the above-formed slurry to 70% in a batch type reactor having a volume of 90 L, while maintaining the temperature at 50 ° C. and the rotational speed at 600 rpm so that the molar ratio of aluminum and the nickel cobalt metal mixture solution is 5 mol%. A 2.0 M sodium aluminate (NaAlO ₂ ) solution and a 5 M sulfuric acid (H ₂ SO ₄ ) solution were added simultaneously. At this time, the input rate of the sodium aluminate (NaAlO ₂ ) solution was 1L / hr and the sulfuric acid solution was added in the same mole number as sodium aluminate. The reaction time was 1 hour. After washing with distilled water and the slurry in the reactor and a high purity of the filtered dried in a vacuum oven 12 hours at 110 ℃ to nickel cobalt aluminum composite metal hydroxide _{Ni 0 .8 Co 0 .15 Al 0} .05 (OH) 2 was obtained.

Example 3.3 Preparation of Cathode Active Material

Lithium metal composite oxide Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ was obtained in the same manner as in Example 1.3, with a yield of 94.6%.

<Example 4>

Example 4.1 Synthesis of Nickel Cobalt Composite Hydroxide-Continuous Synthesis

It proceeded in the same manner as in Example 2.1. The collected hydroxide was filtered and washed with distilled water of high purity, and dried in a vacuum oven at 110 ° C. for 12 hours to obtain a nickel / cobalt metal complex hydroxide [Ni0.84Co0.16 (OH) 2].

Example 4.2 Introduction of Aluminum

Aluminum isopropoxide (Al (Oi-Pr) ₃ ) corresponding to Al / (Ni + Co) = 0.05 was mixed with the obtained nickel cobalt hydroxide and mixed using a high speed mixer. The mixture was placed in a Cordilite crucible (Sega) and heat treated at 400 ° C., 5 hours, 550 ° C., and 8 hours under an air stream.

Example 4.3 Preparation of Positive Electrode Active Material

The heat-treated product was mixed with lithium hydroxide (LiOH.H 2 O) in a molar ratio of Li / (Ni + Co + Al) = 1.03, placed in a Cordilite crucible (Sega), and calcined at 750 ° C. for 20 hours in an oxygen atmosphere. The chemical composition of the plastic is water lithium metal composite oxide is an _{O 2 Li (Ni 0 .8 Co} 0 .15 Al 0 .05), total yield is 97.5%

Example 5

In the introduction of aluminum in Example 4.2, the aluminum raw material was carried out in the same manner as in Example 4 except that aluminum hydroxide (Al (OH) ₃ ) was used instead of aluminum isopropoxide (Al (Oi-Pr) 3). A lithium metal composite oxide Li [Ni _0.8 Co _0.15 Al _0.05 ) O ₂ was obtained in a yield of 97.1%.

<Example 6>

Example 6.1 Synthesis of Nickel Cobalt Composite Hydroxide-Batch Synthesis

Nickel cobalt hydroxide was synthesized in the same manner as in Example 2. Taken out of the reactor slurry 110 ℃ then washed with distilled water filtered and highly purified, and dried 12 hours in a vacuum oven nickel / cobalt metal complex hydroxide _{[Ni 0 .84 Co 0 .16 (} OH) 2] to give the

Example 6.2 Introduction of Aluminum and Preparation of Cathode Active Material

In the obtained nickel cobalt hydroxide, aluminum hydroxide (Al (OH) ₃ ) corresponding to Al / (Ni + Co) = 0.05 and lithium hydroxide (LiOH · H 2 O) were added at a high molar ratio of Li / (Ni + Co + Al) = 1.03. Mix using a mixer. The mixture was placed in a Cordilite crucible (Sega) and calcined at 550 ° C. for 10 hours, 750 ° C. for 20 hours under an oxygen atmosphere. The chemical composition of the plastic is water lithium metal composite oxide is an _{O 2 Li (Ni 0 .8 Co} 0 .15 Al 0 .05), the total yield was 96.8%.

Comparative Example 1

Comparative Example 1.1 Synthesis of Nickel Cobalt Aluminum Hydroxide-Continuous Synthesis

2.0M nickel sulfate hexahydrate (NiSO ₄ · 6H ₂ O), cobalt sulfate hexahydrate (CoSO _{4 ·} 7H ₂ O) and aluminum nitrate hexahydrate (Al ( NO ₃ ) _3. 9H ₂ O) were mixed at the same time to prepare a mixed metal solution. A continuous reactor with a volume of 90 L filled with 1 M aqueous ammonia solution was used, and the pH of the initial solution ranged from 11 to 12. The prepared 2.0 M nickel cobalt metal mixture solution, 28% aqueous ammonia and 25% sodium hydroxide solution was continuously added at the same time using a metering pump while stirring at a speed of 600 rpm. At this time, while maintaining the temperature in the reactor 50 ℃, the metal mixture solution was 2.5L / hr, ammonia water was added at a rate of 0.2L / hr, sodium hydroxide was continuously reacted while adjusting the input amount to maintain the pH in the reactor 10.6 ~ 11.6 Was performed. Reactor residence time is 17 hours. The slurry, which is a reaction product discharged through the reactor overflow as a continuous reaction, was filtered and washed with high purity distilled water, and then dried in a vacuum oven at 110 ° C. for 12 hours to form nickel cobalt aluminum metal composite hydroxide Ni _0.8 Co _0.15 Al _0.05 (OH ) ₂ was obtained.

Comparative Example 1.2 Preparation of Cathode Active Material

In the same manner as in Example 1.3, the chemical composition of the resulting lithium metal composite oxide was Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ , the total yield was 89.8%.

Comparative Example 2

After synthesis of nickel cobalt aluminum metal complex hydroxide, except that fine powder of nickel cobalt aluminum hydrate was removed using hydrocyclone, the lithium metal composite oxide Li (Ni _0.8 Co _0.15 Al _0.05 was obtained in the same manner as in Comparative Example 1 in a total yield of 80.1%. ) O ₂ was synthesized.

Experimental Example 1 Calculation of Process Yield

The synthesis method of the metal composite hydroxide, the aluminum introduction method / raw material and the synthesis process time and the process yield of the final synthesized lithium metal composite oxide performed in Examples 1 to 6 and Comparative Examples 1 to 2 are summarized in Table 1 below Indicated.

Table 1 Manufacturing Condition and Yield of Lithium Metal Composite Oxide

number	division	Precursor synthesis	Al doping method	Al raw material	Hydroxide Synthesis Process Time (hr)				Process yield (%)
					Precursor	Al Doping	Other*	system
One	Example 1	Continuous	Dope	Al (NO 3 ) 3	8	One	0	9	97.2
2	Example 2	Batch	Dope	Al (NO 3 ) 3	8	One	0	9	96.1
3	Example 3	Continuous	Dope	NaAlO 2	8	One	0	9	95.6
4	Example 4	Continuous	Dope	Al-O-iP	8	0	0	8	97.5
5	Example 5	Continuous	Dope	Al (OH) 3	8	0	0	8	97.1
6	Example 6	Batch	Dope	Al (OH) 3	8	0	0	8	96.8
7	Comparative Example 1	Continuous	Coincidence	Al (NO 3 ) 3	20	0	0	0	89.8
8	Comparative Example 2	Continuous	Coincidence	Al (NO 3 ) 3	20	0	One	21	80.1

* Other: process time for hydrocyclones

In Table 1, the hydroxide synthesis process time of Examples 1 to 6 after aluminum was introduced into the nickel cobalt composite hydroxide was 10 hours or less, compared to Comparative Examples 1 and 2 in which aluminum was simultaneously introduced in the hydroxide synthesis step, and the process time was 50. Improved to less than% was confirmed that the production capacity of the metal complex hydroxide is more than doubled. In addition, it can be seen that the total process yield of the lithium metal composite oxides of Examples 1 to 6 was also improved to 97.5% (Example 4), which is significantly greater than that of Comparative Examples 1 and 2.

Experimental Example 2 XRD Measurement

Powder XRD (X-Ray Diffraction) was measured to analyze the crystal structures of all the lithium metal composite oxides prepared in Examples 1 to 6 and Comparative Examples 1 and 2, and a graph thereof is shown in FIG. Parameter values and result values are shown in Table 2 below.

As a result of XRD analysis, the aluminum-incorporated lithium metal composite oxide obtained in Examples 1 to 6 was 1.1 or more on all of the I ₀₀₃ / I ₁₀₄ planes, and the R factor was 0.43 or less, and was compared in a single phase without impurities. Compared with Examples 1 and 2, it was confirmed that the composite layer was composed of a desired layered structure by showing structural features equal to or higher than those of Examples 1 and 2.

TABLE 2 XRD Result Value

No	a	c	c / a	Volume (Å3)	I 003 / I 104	R factor ([I 006 + I 102 ] / I 101 )
Example 1	2.870	14.181	4.941	101.16	1.150	0.43
Example 2	2.863	14.173	4.951	100.60	1.198	0.41
Example 3	2.861	14.166	4.951	115.97	1.114	0.41
Example 4	2.874	14.198	4.941	101.54	1.163	0.42
Example 5	2.869	14.186	4.945	101.12	1.178	0.42
Example 6	2.866	14.191	4.952	100.94	1.191	0.41
Comparative Example 1	2.867	14.189	4.949	101.00	1.145	0.41
Comparative Example 2	2.863	14.181	4.952	100.67	1.189	0.40

Experimental Example 3 Particle Size Distribution Measurement

The particle size distributions of all the lithium metal composite oxides prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were measured by a particle size analyzer, and are shown in Table 3 below. All of D10 of Examples 1 to 6, which applied the manufacturing process of post-incorporation of dissimilar metal aluminum, were 4.0 μm or more, and had much more uniform and less fine particles than Comparative Examples 1 to 2 using the co-precipitation method. In addition, it was found that the fine particles and the particles were agglomerated less than Comparative Examples 1 to 2 because the D90 was small.

TABLE 3 PSD Data

PSD (μm)	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Comparative Example 1	Comparative Example 2
D10	5.33	5.31	5.22	5.11	5.09	5.01	4.15	4.47
D50	7.27	7.55	7.30	7.34	7.39	7.22	7.39	7.29
D90	10.17	11.82	11.09	11.06	11.28	10.92	11.99	11.87

Experimental Example 4 SEM Measurement

In order to observe the particle shape and the surface of all the lithium metal composite oxides prepared in Examples 1 to 6 and Comparative Examples 1 and 2, the particles were observed with an electron scanning microscope (SEM), and the results are shown in FIGS. 2 to 9, respectively. It was. It can be seen that small primary particles of 10 to 100 nm all gathered to form secondary particles of 1 to 12 μm having a spherical shape, and it was confirmed that no aluminum raw material particles introduced later existed separately.

In addition, a 5,000-time SEM photograph of the metal complex hydroxide synthesized by the continuous reaction method in Example 1, the metal complex hydroxide synthesized by the batch reaction method in Example 2, and the lithium metal composite hydroxide synthesized in Comparative Example 1 is shown in FIGS. Shown in

Experimental Example 5 SEM and EDS Measurement of Particle Cross Section

Particle cross-sectional SEM of nickel cobalt aluminum metal composite oxide synthesized in Example 1, Example 2 and Comparative Example 1 and its cross section EDS (Energy Dispersive Spectrometry) measurement to compare the data for Example 1, Example 2 and Examples 1 are shown in FIGS. 13 to 15, respectively. As shown in FIGS. 13 to 15, it was confirmed that aluminum, which is a dissimilar metal, was uniformly doped to the inside of the particle.

Experimental Example 6 Coin Half Cell Test

The slurry was prepared by mixing the positive electrode active material synthesized in Examples 1 to 6 and Comparative Examples 1 to 2 with carbon black and PVDF [vinylidene fluoride] (PVDF) and NMP as an organic solvent in a weight ratio of 94: 3: 3. It was. The slurry was applied to an Al foil having a thickness of 20 μm and then dried to prepare a positive electrode. Coin half cell (CR2016) was assembled using a porous polyethylene film (CellGard 2502) as a metal lithium and a separator as a cathode along with the anode, and 1.1M LiPF ₆ EC / EMC / DEC solution was used as an electrolyte. . The coin cell prepared by the above method was subjected to a charge / discharge test at a current density of 0.1 C at 3.0 V to 4.3 V. Initial capacity and efficiency for this is shown in Table 4 below. As can be seen in Figure 16, the initial discharge capacity and efficiency of Examples 1 to 6 after the introduction of the dissimilar metal showed a performance equal to or higher than that of Comparative Examples 1 to 2, which were co-precipitated products.

Table 4 <b> Initial Capacity and Efficiency DATA </ b>

Item	Initial capacity (mAh / g)		efficiency(%)
	charge	Discharge
Example 1	222.9	206.1	92.5
Example 2	221.4	204.7	92.5
Example 3	218.7	202.1	92.4
Example 4	216.1	201.4	93.2
Example 5	215.4	201.2	93.4
Example 6	219.1	201.6	92.0
Comparative Example 1	213.2	197.1	92.4

According to the present invention, it is possible to manufacture a large amount of low-cost lithium metal composite oxide for a lithium secondary battery cathode active material having a simple process and low process cost by reducing a lead time and increasing a process yield. The composite oxide has a small amount of fine powder and high uniformity, which enables high capacity and high performance of the cathode active material.

Claims (9)

1. (a) preparing a nickel cobalt complex hydroxide by coprecipitation by mixing a metal mixture solution containing a nickel-containing compound and a cobalt-containing compound, an aqueous ammonia solution as a complexing agent, and an aqueous alkali solution providing a hydroxyl group as a pH adjusting agent with a solvent;

   (b) introducing a metal element M into the nickel cobalt composite hydroxide obtained in step (a); a method of preparing a lithium secondary battery cathode active material precursor represented by the following [Formula 1].

   [Formula 1]

   Ni _1-yz Co _y M _z (OH) ₂

   (In Formula 1, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, and 0≤y≤0.25, 0≤z≤0.15)
2. The method of claim 1,

   The concentration of metal ions in the metal mixed solution containing the nickel-containing compound and the cobalt-containing compound of step (a) is 1 to 3M, the mixing ratio of the metal and the complexing agent is 1: 0.1 to 2.5, and the temperature inside the reactor is Method for producing a lithium secondary battery positive electrode active material precursor, characterized in that the stirring at 200 to 1000rpm, while maintaining a pH of 30 to 60 ℃, 10-13.
3. The method of claim 1,

   In the step of introducing the dissimilar metal element M into the nickel cobalt composite hydroxide of step (b), the dissimilar metal is introduced by mixing the nickel cobalt composite hydroxide obtained in the step (a), a solution containing a dissimilar metal element M, and a coprecipitation agent. Method for producing a lithium secondary battery positive electrode active material precursor, characterized in that the prepared nickel cobalt composite hydroxide particles, and washing and drying the resulting particles.
4.  The method of claim 3, wherein

   The solution containing the metal element M is an aqueous metal salt solution or a metal acid containing the metal element M, and the co-precipitation agent is a base or acidic solution, the method for producing a lithium secondary battery positive electrode active material precursor.
5. The lithium secondary battery cathode active material precursor prepared by the method of any one of claims 1 to 4.
6. (i) preparing a lithium metal composite hydroxide by mixing the lithium secondary battery cathode active material precursor of claim 5 with a lithium compound; And

   (ii) calcining the lithium metal composite hydroxide to obtain a lithium metal composite oxide; a method of manufacturing a lithium metal composite oxide for a lithium secondary battery cathode active material represented by the following [Formula 2].

   Li _x [Ni _{1 -y- z} Co _y M _z ] O ₂

   (In Formula 2, M is a Group 13 metal element, any one selected from B, Al, Ga, In, Tl, or a combination of two or more, 0.96≤x≤1.05, 0≤y≤0.25, 0≤z≤0.15 being)
7. The method of claim 6,

   In the step (i), the lithium secondary battery cathode active material precursor of claim 5 and the lithium compound in a ratio of 1: 0.96 to 1: 1.05 manufacturing method of a lithium metal composite oxide for a lithium secondary battery cathode active material.
8. The method of claim 6,

   In the step (ii), the lithium secondary battery cathode active material lithium metal composite oxide, characterized in that the firing at 650 to 850 ℃ in an oxygen atmosphere.
9. A lithium metal composite oxide for a lithium secondary battery positive electrode active material prepared by any one of claims 7 to 8

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