KR101568257B1 - Method for preparing lithium nickel oxide-over lithiatied manganese oxide composite and lithium nickel oxide-over lithiatied manganese oxide composite using the same - Google Patents

Abstract

The present invention relates to a process for producing a lithium nickel oxide and a lithium excess manganese oxide composite, and a lithium nickel oxide and a lithium excess manganese oxide composite produced thereby. More particularly, A lithium nickel oxide and a lithium excess manganese oxide composite having a long lifetime and exhibiting excellent safety, and a lithium nickel oxide and a lithium excess manganese oxide composite produced thereby.
The lithium nickel oxide and lithium excess manganese oxide composite according to the present invention is not a simple mixture of lithium nickel oxide and lithium excess manganese oxide but is a composite obtained by pulverization after mixing, spray drying and heat treatment, Not only can exhibit a large output in a short time, but also exhibits excellent safety and long-life characteristics.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a process for preparing a lithium nickel oxide and a lithium excess manganese oxide composite, and a lithium nickel oxide and a lithium excess manganese oxide composite the same}

The present invention relates to a process for producing a lithium nickel oxide and a lithium excess manganese oxide composite, and a lithium nickel oxide and a lithium excess manganese oxide composite produced thereby. More particularly, A lithium nickel oxide and a lithium excess manganese oxide composite having a long lifetime and exhibiting excellent safety, and a lithium nickel oxide and a lithium excess manganese oxide composite produced thereby.

Currently, Ni-MH secondary batteries, which have proven safety as high output cells, have been commercialized as batteries that can be used in electric vehicles and hybrid electric vehicles. The development of lithium secondary batteries, which have better output density and energy density, is also actively conducted .

However, lithium secondary batteries used in electric vehicles require high energy density and characteristics capable of exhibiting large output in a short time, and they must be used for more than 10 years under harsh conditions in which charging and discharging by a large current are repeated in a short time, It is necessary to have safety and long-life characteristics remarkably superior to conventional small-sized lithium secondary batteries.

A lithium ion battery used in a conventional small-sized battery generally uses a layered lithium-cobalt composite oxide as an anode and a graphite-based material as an anode. In the case of a lithium-cobalt composite oxide, cobalt, It is expensive and unsuitable for electric vehicles in terms of safety. Therefore, a lithium manganese composite oxide having a spinel structure composed of manganese, which is inexpensive and excellent in safety, is suitable as an anode of a lithium ion battery for an electric vehicle. However, in the case of the lithium manganese composite oxide, manganese is eluted into the electrolyte due to the influence of the electrolytic solution during high temperature and high current charge / discharge, and degradation of the battery characteristics is required. In addition, the lithium manganese composite oxide has a disadvantage in that the capacity per unit weight is smaller than that of the conventional lithium cobalt composite oxide or lithium nickel composite oxide. Therefore, there is a limitation in increasing the capacity per cell weight, It can be practically used as a power source of an electric vehicle.

In order to overcome these disadvantages, studies have been made to fabricate electrodes using a mixed cathode active material. For example, in Japanese Patent Application Laid-Open Nos. 2002-110253 and 2003-168430, a lithium manganese oxide and / or a lithium cobalt oxide and a lithium nickel-manganese-cobalt composite oxide are mixed However, the lithium manganese oxide has a disadvantage in that it has a problem of poor cycle life and safety improvement.

Japanese Patent Application Laid-Open No. 2002-110253 Japanese Patent Application Laid-Open No. 2003-168430

Disclosure of the Invention The present invention has been made to solve the above-mentioned problems of the prior art and to provide a novel lithium nickel oxide which can secure long life at room temperature and high temperature by repeating charging and discharging at high current, And a process for producing a lithium-excess manganese oxide composite.

The present invention also provides a composite of a lithium nickel oxide and a lithium excess manganese oxide produced by the production method of the present invention.

The present invention has been made to solve the above problems

A first step of mixing a lithium nickel oxide represented by the following Chemical Formula 1 with a lithium excessive manganese oxide represented by Chemical Formula 2;

[Chemical Formula _{1] Li 1 + a Ni b} Co c M 1 - (b + c) O 2 ( In the formula 1 0≤a <0.2, 0.3 <b <0.7, 0 <c <0.4, M is Mn, Al And at least one element selected from the group consisting of Mg, Ni, Co, Fe, Ti, V, Zr and Zn.

???????? Li _{1 + x} Ni _y Co _z M ' _{1 - (y + z)} O ₂ (Y + z) < 0.7, M 'is at least one element selected from the group consisting of Mn, Co and Ni,

Adding a solvent to the mixture to prepare a slurry;

Milling the slurry until the average particle size D ₅₀ is less than or equal to 600 nm;

Adding a dispersant to the pulverized slurry and stirring until the viscosity becomes 1000 to 2000 cp;

Spherical granulating the slurry by spray drying; And

And heat treating the obtained spherical particles in an oxygen atmosphere. The present invention also provides a method for producing a lithium nickel oxide and a lithium excess manganese oxide composite.

In the method for producing the lithium nickel oxide and the lithium excess manganese oxide composite of the present invention, the average size D ₅₀ of the secondary particles of the lithium nickel complex oxide represented by the formula (1) and the lithium manganese composite oxide represented by the formula (2) 25 占 퐉.

In the method for producing a composite of a lithium nickel oxide and a lithium excess manganese oxide according to the present invention, the lithium excess manganese oxide represented by the general formula (2) is added in an amount of 25 to 100 parts by weight per 100 parts by weight of the lithium nickel oxide represented by the general formula Is mixed.

In the method for producing a composite of lithium nickel oxide and lithium excess manganese oxide according to the present invention, the solvent is distilled water or alcohol.

In the method for producing the lithium nickel oxide and the lithium excess manganese oxide composite of the present invention, the injection temperature and the discharge temperature are 230 to 270 ° C. and 100 to 120 ° C., respectively.

In the method for producing the lithium nickel oxide and the lithium excess manganese oxide composite of the present invention, the heat treatment is performed at 500 to 700 ° C for 1 to 3 hours.

The present invention also provides a lithium nickel oxide and a lithium excess manganese oxide composite produced by the method of the present invention for producing a lithium nickel oxide and a lithium excess manganese oxide composite.

The present invention also provides a lithium secondary battery comprising the lithium nickel oxide and the lithium excess manganese oxide composite according to the present invention.

The lithium nickel oxide and the lithium excess manganese oxide according to the present invention are not simply mixed with lithium nickel oxide and lithium excess manganese oxide but are pulverized after mixing and pulverized and spray-dried and heat treated to be granulated, The composite of nickel oxide and lithium excess manganese oxide exhibits high energy density and high output in a short time, as well as excellent safety and long life characteristics.

FIG. 1 schematically shows a method for producing a composite of a lithium nickel oxide and a lithium excess manganese oxide according to the present invention.
FIG. 2 is a SEM photograph of the lithium nickel oxide and the lithium excess manganese oxide composite prepared in one embodiment and the comparative example of the present invention.
FIG. 3 shows charge / discharge characteristics of a battery manufactured using the cathode active material prepared in one embodiment of the present invention and a comparative example.
FIG. 4 shows the rate characteristics of a battery manufactured using the cathode active material prepared in one embodiment of the present invention and a comparative example.
FIG. 5 shows lifetime characteristics of a battery manufactured using the cathode active material prepared in one embodiment of the present invention and a comparative example.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited by the following examples.

< Manufacturing example > Preparation of Lithium Excess Manganese Oxide

(NiSO ₄ .6H ₂ O), cobalt sulfate heptahydrate (CoSO ₄ .7H ₂ O) and manganese sulfate monohydrate (MnSO ₄ ) were added so that the molar ratio of Ni: Co: Mn was 28:12:60. H ₂ O) mixed metal solution was prepared. A continuous reactor having an internal volume of 90 L filled with 1 M aqueous ammonia was used and the pH of the initial solution was in the range of 10 to 11. The prepared 2.5 M nickel / cobalt / manganese mixed metal solution, 28% ammonia water, and 18% sodium carbonate solution were continuously and simultaneously introduced into the reactor at a rate of 500 rpm using a metering pump while stirring under nitrogen. At this time, the temperature in the reactor was maintained at 55 ° C., the mixed metal solution was fed at a rate of 3 L / hr, the ammonia water was fed at a rate of 0.2 L / hr, and the sodium carbonate was continuously fed Respectively. The reactor retention time was 10 hours. The slurry, which is the reaction product discharged through the reactor overflow in a continuous reaction, was collected. The slurry solution collected from 30 hours after the start of the reaction was filtered and washed with high purity distilled water and dried in a vacuum oven at 110 ° C for 12 hours to obtain a precursor nickel / cobalt / manganese metal complex hydroxide. The composition of this composite metal carbonate is Co _{0 .28 0 .12} Ni was Mn _{0 .60} (CO _3). The dried composite metal carbonate was mixed with lithium carbonate (Li ₂ CO ₃ ) at a molar ratio of Li / (Ni + Co + Mn) = 1.25 and placed in a Cordilite crucible. Followed by baking for 10 hours to obtain a lithium metal composite oxide. The chemical composition of the calcined lithium metal composite oxide was Li _{1 .25} [Ni _{0 .21} Co _{0 .09} Mn _{0 .45} ] O ₂ .

< Example > Lithium nickel oxide and Lithium excess  Preparation of manganese oxide complex

Having an average particle size of 10 ㎛ as marketed commercially as lithium nickel oxide _{Li [Ni 1/3 Co 1/3 Mn 1/3} ] O 2 with average particle size of the lithium 15 ㎛ an excess of manganese oxide obtained in Preparation Example _{1 Li. 25} and mixed with the [Ni Co _{0 .21 0 .09 0 .45} Mn] O ₂ down ratio.

_{Li [Ni 1/3 Co 1} /3 Mn 1/3] O 2 _{Li 1 .25 [Ni 0 .21 Co} 0 .09 Mn 0 .45] O 2 Example 1 10 90 Example 2 15 85 Example 3 20 80

DIW was added to the mixture so that the solid content became 30 wt%, followed by pulverization for 30 minutes using beads mill (Netch, LabStar Mini). 1 wt% of a dispersant was added to the pulverized slurry, and the mixture was stirred for 10 minutes to obtain a viscosity of 1,000 to 2,000 cp, followed by sphering using a spray dryer (DONGJIN KYEON, DJE003R). The atomizer used for spray drying is a two-fluid spray nozzle with an inlet temperature of 250 ° C and an outlet temperature of 110 ° C.

The spherical particles obtained by using a spray dryer were heat-treated at 550 ° C for 2 hours in oxygen-containing air atmosphere to obtain a composite of lithium nickel oxide and lithium excess manganese oxide.

< Comparative Example >

Lithium nickel oxide _{Li [Ni 1/3 Co 1} /3 Mn 1/3] O 2 20 parts by weight of lithium excess manganese oxide _{Li 1.25 [Ni 0.21 Co 0.09 Mn} 0.45] O 2 80 parts by weight by mixing parts of simple was determined as Comparative Example .

< Experimental Example > SEM  Photo measurement

SEM photographs of the lithium nickel oxide and lithium excess manganese oxide composite prepared in Examples 1 to 3 and Comparative Examples were measured and shown in FIG.

< Experimental Example > Particle properties measurement

The results of measurement of the particle diameter and BET surface area of the lithium nickel oxide and lithium excess manganese oxide composite prepared in Examples 1 to 3 and Comparative Examples are shown in Table 2 below.

Item Example 1 Example 2 Example 3 Comparative Example ICP composition _{Li 1 .23 [Ni 0 .22 Co} 0 .12 Mn 0 .44] O 2 _{Li 1 .22 [Ni 0 .23 Co} 0 .13 Mn 0 .43] O 2 _{Li 1 .21 [Ni 0 .23 Co} 0 .14 Mn 0 .43] O 2 _{Li 1 .21 [Ni 0 .23 Co} 0 .14 Mn 0 .43] O 2 D ₅₀ (占 퐉) 8.8 8.7 8.9 9.2 BET (m ² / g) 3.54 3.58 3.49 2.92

< Manufacturing example >

The positive electrode active material for a lithium secondary battery prepared according to each of Examples 1 to 3 and Comparative Examples was mixed with acetylene black as a conductive agent and polyvinylidene fluoride (PVdF product name: solef6020) as a binder in a weight ratio of 90: 5: 5 To prepare a slurry. The slurry was uniformly coated on an aluminum foil having a thickness of 20 占 퐉 and vacuum-dried at 130 占 폚 to prepare a positive electrode for a lithium secondary battery.

An electrolytic solution obtained by dissolving LiPF ₆ at a concentration of 1 M in a solvent mixed with ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3: 7 was used as a separator, using the above anode and lithium foil as counter electrodes and a porous polyethylene film having a thickness of 25 탆 as a separator. A coin cell was produced by a conventional method.

< Experimental Example > Evaluation of battery characteristics

The initial capacity and the rate characteristics of the coin cell manufactured using the cathode active materials of the examples and comparative examples were evaluated and shown in Table 3 and FIG. 3 and FIG. 4, respectively.

Item unit Example 1 Example 2 Example 3 Comparative Example 0.1C charge mAh / g 283.4 276.5 266.4 286.4 0.1 C discharge mAh / g 252.6 248.1 230.4 251.5 Efficiency % 89.1% 89.7% 86.5% 87.8% 0.2C mAh / g 241.5 236.9 221.4 239.9 0.5 C mAh / g 221.9 218.8 207.8 223.9 1.0 C mAh / g 204.3 203.8 195.7 208.0 1.5 C mAh / g 191.9 194.6 188.4 194.5 2.0C mAh / g 182.4 187.4 182.3 183.4 5.0 C mAh / g 146.5 164.8 163.8 135.8 0.2C vs. 0.1 C % 95.6% 95.5% 96.1% 95.4% 0.5C vs. 0.1 C % 87.9% 88.2% 90.2% 89.0% 1.0C etc. 0.1 C % 80.9% 82.1% 84.9% 82.7% 1.5C vs. 0.1 C % 76.0% 78.5% 81.8% 77.3% 2.0C etc. 0.1 C % 72.2% 75.5% 79.1% 72.9% 5.0C vs. 0.1 C % 58.0% 62.0% 71.1% 54.0%

< Experimental Example > Evaluation of battery characteristics

The life characteristics of the coin cells manufactured using the cathode active materials of the above Examples and Comparative Examples were evaluated and shown in Table 4 and FIG.

Example 1 Example 2 Example 3 Comparative Example Capacity Retention (%) at 100th cycle 72.4% 79.2% 83.2% 61.4%

Claims (8)

Preparing a mixture of a lithium nickel oxide and a lithium excess manganese oxide by mixing a lithium nickel oxide represented by the following Chemical Formula 1 and a lithium excessive manganese oxide represented by Chemical Formula 2;
[Chemical Formula _{1] Li 1 + a Ni b} Co c M 1- (b + c) O 2 ( In the formula 1 0≤a <0.2, 0.3 <b <0.7, 0 <c <0.4, M is Mn, Al And at least one element selected from the group consisting of Mg, Ni, Co, Fe, Ti, V, Zr and Zn.
[Chemical Formula _{2] Li 1 + x Ni y} Co z M '1- (y + z) O 2 (0.2 <x <0.7, 0.2 <y <0.7, 0.3 <1- (y + z in the above formula (2)) < 0.7, and M 'is at least one element selected from the group consisting of Mn, Co, and Ni)
Adding a mixture of lithium nickel oxide and lithium excess manganese oxide to a solvent to prepare a slurry;
Milling the slurry until the average particle size D ₅₀ is less than or equal to 600 nm;
Adding a dispersant to the pulverized slurry and stirring until the viscosity becomes 1000 to 2000 cp;
Spherical granulating the slurry by spray drying; And
And heat treating the obtained spherical particles in an oxygen atmosphere. The method of producing a lithium nickel oxide and a lithium excess manganese oxide composite according to claim 1,
The method according to claim 1,
Wherein an average size D ₅₀ of the secondary particles of the lithium nickel complex oxide represented by Formula 1 and the lithium excess manganese composite oxide represented by Formula 2 is 10 to 25 탆, Gt;
The method according to claim 1,
Wherein the lithium-excess manganese oxide represented by Formula 2 is mixed in an amount of 25 parts by weight to 100 parts by weight per 100 parts by weight of the lithium nickel oxide represented by Formula 1, and a process for producing the lithium-excess manganese oxide composite.
The method according to claim 1,
Wherein the solvent is distilled water or alcohol. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The method according to claim 1,
Wherein the spraying-drying temperature is from 230 to 270 DEG C and the discharge temperature is from 100 to 120 DEG C. 6. The method for producing a lithium nickel oxide and lithium excess manganese oxide composite according to claim 1,
The method according to claim 1,
Wherein the heat treatment is performed at 500 to 700 占 폚 for 1 hour to 3 hours. The method for producing a lithium nickel oxide and lithium excess manganese oxide composite according to claim 1,
A lithium nickel oxide and a lithium excess manganese oxide composite produced by the method of any one of claims 1 to 6.
A lithium secondary battery comprising the lithium nickel oxide and the lithium excess manganese oxide composite according to claim 7.

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