KR20190076774A - Positive electrode active material precursor for rechargable lithium battery and manufacturing method of the same, positive electrode active material for rechargable lithium battery and manufacturing method of the same, rechargable lithium battery - Google Patents

Abstract

Disclosed by the present invention is a cathode active material precursor for a lithium secondary battery including metal hydroxide represented by chemical formula 1, Ni_(1-w-x-y-z)Ti_wM1_xM2_yM3_z(OH)_(2-p)X_p. In the chemical formula 1, M1 and M2 are different from each other and each of the M1 and M2 is any one element selected from a group consisting of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr, and Ga; M3 is at least one element of Ni, Co, Mn, Al, and Ti; and X is any one element selected from a group consisting of F, N, S, and P, wherein each of w, x, y, z, and p satisfies inequations, 0 < w <= 0.2, 0 < x < 0.3, 0 <= y <= 0.1, 0 <= z <= 0.1, and 0 <= p <= 0.1. The present invention is provided for excellent characteristics of rate and durability.

Description

FIELD OF THE INVENTION The present invention relates to a positive electrode active material precursor for a lithium secondary battery and a method for producing the same, a positive electrode active material for a lithium secondary battery and a method for producing the same, a lithium secondary battery, and a lithium secondary battery. MANUFACTURING METHOD OF THE SAME, RECHARGABLE LITHIUM BATTERY}

The present disclosure relates to a positive electrode active material precursor for a lithium secondary battery, a positive electrode active material for a lithium secondary battery, and a lithium secondary battery excellent in a rate characteristic and a life characteristic.

2. Description of the Related Art In recent years, portable electronic devices such as AV devices and personal computers have been rapidly made portable and wireless, and as a driving power source therefor, there is a growing demand for secondary batteries having small and lightweight high energy densities. In recent years, development and commercialization of electric vehicles and hybrid vehicles have been carried out for the global environment, and the demand for lithium ion secondary batteries having excellent storage characteristics in a medium to large size has been increasing. Under such circumstances, a lithium ion secondary battery having a large charge / discharge capacity and an excellent life characteristic has been attracting attention.

Conventionally, LiMn ₂ O ₄ of a spinel type structure, LiMnO ₂ of a zigzag layer type structure, LiCoO ₂ and LiNiO ₂ of a layered rock salt type structure are generally used as a cathode active material useful for a high energy type lithium ion secondary battery having a voltage of 4 V class Among them, a lithium ion secondary battery using LiNiO ₂ is attracting attention as a battery having a high charge / discharge capacity. However, this material is inferior in thermal stability and charging / discharging cycle durability at the time of charging, and further improvement in characteristics is required.

That is LiNiO ₂ when pulled nd lithium Ni ^{3 +} a Ni ^{4 +} is the yarn determined in TB modifying the inner surface to pull additional Li in the area extracted 0.45 mol Li monoclinic (單斜) forward causing a hexagonal structure Change.

Therefore, the charge / discharge reaction is repeated to make the crystal structure unstable and the cycle characteristics to deteriorate

In order to solve this problem, studies have been made on a material in which Co and Al are added to a part of Ni of LiNiO _2. However, materials solving these problems have not been obtained yet, and a Li- Oxides are required.

Embodiments are to provide a positive electrode active material precursor for a lithium secondary battery, a positive electrode active material for a lithium secondary battery, and a lithium secondary battery having excellent rate characteristics and life characteristics through the content and distribution of titanium.

A precursor of a cathode active material for a lithium secondary battery according to an embodiment of the present invention includes a metal hydroxide represented by the following Chemical Formula 1.

[Chemical Formula 1]

Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p

In the formula 1, M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are 0 <w? 0.2, 0 <x <0.3, 0? Y? 0.1, 0? Z? 0.1, 0? P?

The precursor may include a metal hydroxide represented by the following formula (2).

(2)

Ni _1-wx Co _x Ti _w (OH) _2-p X _p

(Wherein X is an element selected from the group consisting of F, N, S, and P, and w, x, and p are 0.02 < w? 0.2, 0 & &Lt; / RTI &gt;

The precursor of a cathode active material for a lithium secondary battery according to an embodiment of the present invention is a precursor of a cathode active material for a lithium secondary battery comprising a metal hydroxide represented by the following Chemical Formula 1, wherein the precursor is divided into a core and an outer periphery surrounding the core, There is a difference between the Ti concentration in the outer region and the Ti concentration in the outer region.

[Chemical Formula 1]

Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p

In the formula 1, M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are 0 <w? 0.2, 0? X <0.3, 0? Y? 0.1, 0? Z? 0.1, 0? P?

The outer Ti concentration may be higher than the Ti concentration of the core.

The Ti concentration of the core may be less than 50% based on 100% of the total Ti weight, and the Ti concentration of the core may exceed 50%.

According to an embodiment of the present invention, there is provided a method for preparing a precursor of a cathode active material for a lithium secondary battery, comprising: obtaining a first precursor by coprecipitation reaction of a nickel raw material and a heterogeneous raw material; And reacting the first precursor with a titanium raw material to obtain a second precursor separated from the core by surrounding the core and the core, wherein the second precursor has a Ti concentration of the core and a Ti concentration And a metal hydroxide represented by the following formula (1).

[Chemical Formula 1]

Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p

In the formula 1, M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are 0 <w? 0.2, 0? X <0.3, 0? Y? 0.1, 0? Z? 0.1, 0? P?

In the step of obtaining the first precursor, the first precursor may include a metal hydroxide satisfying the following formula (3).

(3)

Ni _1-xyz M _{1 x} M 2 _y M 3 _z (OH) _2-p X _p

In the above formula (3), M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are each an element selected from the group consisting of F, N, S, and P, and 0, 0, z? 0.1, 0? p? 0.1).

A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes a metal oxide represented by Chemical Formula 4 below.

[Chemical Formula 4]

Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p

(Wherein M 1 and M 2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are 0 <w? 0.2, 0 <x <0.3, 0? Y? 0.1, 0? Z? 0.1, 0? P? 0.1, and -0.1? M?

A cathode active material for a lithium secondary battery according to an embodiment of the present invention is a cathode active material for a lithium secondary battery comprising a metal oxide represented by the following Chemical Formula 4, wherein the cathode active material includes a core and an outer casing surrounding the core, There is a difference between the Ti concentration and the outer Ti concentration.

[Chemical Formula 4]

Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p

(Wherein M 1 and M 2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, p and m are 0 <w? 0.2 and 0 <x <0.3, respectively, where w, x, y, z, p and m are each an element selected from the group consisting of F, N, , 0 = y? 0.1, 0? Z? 0.1, 0? P? 0.1, and -0.1? M? 0.2.

The outer Ti concentration may be higher than the Ti concentration of the core.

According to an embodiment of the present invention, there is provided a method for preparing a cathode active material for a lithium secondary battery, comprising: obtaining a first precursor by coprecipitation reaction of a nickel raw material and a heterogeneous raw material; And mixing and firing the first precursor, the lithium source material, and the titanium source material to obtain a cathode active material represented by Formula 4 below.

[Chemical Formula 4]

Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p

(Wherein M 1 and M 2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, p and m are 0 <w? 0.2 and 0 <x <0.3, respectively, where w, x, y, z, p and m are each an element selected from the group consisting of F, N, , 0 = y? 0.1, 0? Z? 0.1, 0? P? 0.1, and -0.1? M? 0.2.

In the step of obtaining the first precursor, the first precursor may include a metal hydroxide satisfying the following formula (3).

(3)

Ni _1-xyz M _{1 x} M 2 _y M 3 _z (OH) _2-p X _p

In the above formula (3), M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Cd, In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, X, y, z, and p are each an element selected from the group consisting of F, N, S, and P, 0 <x <0.3, 0? Y? 0.1, 0 <z Lt; = 0.1, 0 &lt; / = p &lt;

In the step of obtaining the positive electrode active material, the firing temperature may be 700 to 850 캜.

A lithium secondary battery including a cathode active material for a lithium secondary battery according to an embodiment of the present invention includes: a cathode; cathode; And an electrolyte.

The initial activation voltage may be 4.4 to 4.6V.

A precursor capable of stable oxidation combination can be expected by controlling the content of titanium.

High-capacity and high-stability multicomponent cathode active materials can be expected through controlling the content and distribution of titanium.

A lithium secondary battery having excellent rate characteristics and life characteristics can be expected through control of the firing temperature and the initial activation voltage.

1 is a scanning electron microscope (SEM) photograph showing the difference in the surface shape of the cathode material according to the difference between the embodiment and the comparative example.
FIG. 2 is a graph showing a discharge voltage drop phenomenon in 4.2 V and 3.5 V discharge sections of a comparative example compared with the embodiment when applying a 4.5 V activation voltage.
3 is a view showing XRD of a Ti over-substituted cathode material.
4 is a graph showing the discharge capacity and rate characteristics when applying the initial activation voltage of 4.5 V in the embodiment.
5 is a graph showing the discharge capacity and the rate characteristic when applying the 1 ^st activation voltage of 4.5 V in the embodiment.
6 is a graph showing the discharge capacity and the rate characteristic according to the Ti addition amount change in the embodiment.
Fig. 7 is a graph showing lifetime characteristics of the battery according to the Ti addition amount change in the examples. Fig.
8 is a SEM (scanning electron microscope) photograph according to the Ti addition amount change in the example.
9 is a graph showing the discharge capacity and the rate characteristic according to the Li / metal ratio change in the embodiment.
10 is a graph showing lifetime characteristics of a battery according to the Li / metal ratio change of the embodiment.
11 is a SEM (scanning electron microscope) photograph according to the variation of Li / metal ratio in the embodiment.
12 is a graph showing the discharge capacity and the rate characteristic according to the heat treatment temperature change in the embodiment.
13 is a graph showing lifetime characteristics of the battery according to the heat treatment temperature change of the embodiment.
14 is a SEM (scanning electron microscope) photograph according to the heat treatment temperature change of the embodiment.
15 is a view schematically showing a typical structure of a lithium battery according to an embodiment of the present invention.

Hereinafter, various 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 carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings. In the drawings, the thickness is enlarged to clearly represent the layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Also, when a portion such as a layer, a film, an area, a plate, etc. is referred to as being "on" or "on" another portion, this includes not only the case where the other portion is "directly on" . Conversely, when a part is "directly over" another part, it means that there is no other part in the middle. Also, to be "on" or "on" the reference portion is located above or below the reference portion and does not necessarily mean "above" or "above" toward the opposite direction of gravity .

Also, throughout the specification, when an element is referred to as "including" an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Cathode active material precursor for lithium secondary battery

First embodiment

In one embodiment of the present invention, the precursor of a cathode active material for a lithium secondary battery includes a metal hydroxide represented by the following general formula (1).

[Chemical Formula 1]

Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p

In Formula 1, M 1 and M 2 are different from each other, and Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, M3 is any one element selected from the group consisting of In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga. It is an element.

X is any one element selected from the group consisting of F, N, S and P, and w, x, y, z and p satisfy 0? W? 0.2, 0? X? 0.1, 0? Y? 0.3, z? 0.1, 0? p? 0.1, and the Ni mole fraction of the precursor produced from the above formula (1) is 0.8 or more.

As described above, among the conventional ternary cathode active materials based on nickel-cobalt-manganese, in particular, in the case of the High nickel-based positive electrode active material having a nickel content of 80% or more aiming at high capacity expression, There was a perception of the problem.

In order to solve such a problem, the precursor of the cathode active material for a lithium secondary battery according to an embodiment of the present invention replaces manganese with titanium. Titanium is an element of the same period as manganese and has an oxidation potential of +4, so that stable oxidation can be combined with manganese.

Accordingly, not only high-dose expression is possible, but high-rate characteristics can be expected. In addition, excellent lifetime characteristics and high temperature stability can be exhibited.

Nickel is contained in a high content and can be preferably used for producing a high capacity cathode active material. The content of nickel depends on the contents of titanium, M1, M2 and M3. When the molar fraction of nickel is less than 0.8, it may be difficult to expect a high capacity.

Titanium is an element for replacement of manganese and is essentially contained in a cathode active material precursor for a lithium secondary battery according to an embodiment of the present invention. When the molar fraction of titanium is 0.2 or more, it may be difficult to expect high-capacity and high-rate characteristics, and when not included, excellent lifetime characteristics and high-temperature stability may not be exhibited. Titanium can be evenly distributed in the precursor.

M1 and M2 are selected from the group consisting of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, La, W, Ce, Sm, Gd, Yb, Sr and Ga, and M3 is at least one selected from Ni, Co, Mn, Al and Ti.

X may be selected from the group consisting of F, N, S and P as coating elements. When the coating element is F, most of the fluorine is located on the surface of the lithium metal oxide, so that it is expected to suppress the generation of gas by electrolysis decomposition under high voltage and increase the thermal stability.

The precursor of the cathode active material for a lithium secondary battery according to an embodiment of the present invention may include a metal hydroxide represented by the following formula (2).

(2)

Ni _1-wx Co _x Ti _w (OH) _2-p X _p

X is an element selected from the group consisting of F, N, S and P, and w, x and p are respectively 0.02? W? 0.2, 0? X? 0.18, w + x? 0.2, p? 0.1.

Titanium has a content range of 0.02? W? 0.2. By having a content of 0.02 or more, high-rate characteristics can be expected, and lifetime characteristics and high-temperature stability can be expected to be improved.

The molar fraction of cobalt can be in the range of 0 to 0.18. As the w and x satisfy 0.02? w? 0.2, 0? x? 0.18 and w + x? 0.2, the molar fraction of nickel can be controlled to a value of 0.8 to 0.98. When the molar fraction of nickel satisfies the above range, it is expected that high-rate characteristics, lifetime characteristics and high-temperature stability through high-capacity expression and stable oxidation of nickel are increased.

The method for preparing a precursor of a cathode active material for a lithium secondary battery according to the first embodiment of the present invention includes a step of obtaining a precursor by coprecipitation reaction of a nickel raw material, a titanium raw material and a heteroatom raw material, Metal hydroxides.

First, for the coprecipitation reaction, the nickel raw material, the titanium raw material, the heterogeneous raw material and the solvent are mixed and dissolved by mixing to satisfy the stoichiometric ratio. At this time, the complexing agent can be partially mixed.

The nickel raw material is not particularly limited as long as it is a substance in which cations and certain anions are ionically bonded and is dissolved in water to dissociate into cations and anions. Specifically, it may be a sulfate, a nitrate, and a hydrochloride or a mixture thereof.

Further, the titanium raw material is not particularly limited as long as it is a substance in which cations and certain anions are ionically bonded and is dissolved in water to dissociate into cations and anions. Specifically, it may be a sulfate, a sulfate hydrate, or a mixture thereof.

The heterogeneous elementary raw material is a substance in which a metal cation other than nickel and titanium (for example, cations such as Co, Al, Mn, Mg, Zr, Sn, Ca, Ge, Cr and Fe) And is not particularly limited as long as it is a substance dissociated into cations and anions. Specifically, it may be a sulfate, a nitrate, and a hydrochloride or a mixture thereof.

In the above formula (1), M 1 and M 2 are each a different element, and M 3 is at least one element selected from the group consisting of Ni, Co, Mn, Al and Ti.

The solvent has polarity, and distilled water can be used.

The raw materials dissolved in the solvent and homogeneously mixed in the atomic unit may contain a solution in which the homogeneous composition is precipitated by the introduction of the precipitant and the residual salt is dissolved.

The precipitant may function as a pH adjusting agent. An alkaline solution having a hydroxyl group selected from sodium hydroxide (NaOH), potassium hydroxide (KOH) and lithium hydroxide (LiOH), or a mixture thereof may be used. At this time, addition of a complexing agent such as NH ₄ OH, Na ₂ CO ₃ , or organic acid (organic acid) may be advantageous for controlling the shape of the precursor obtained.

The molar concentration of the metal in the solution in which the nickel raw material, the titanium raw material and the heterogeneous raw material are dissolved may be controlled to be 2.0 to 3.0 M. The precursor can be densely synthesized by satisfying the above-mentioned molarity of the metal in the solution, and the energy density can be expected to be increased.

The precursor prepared by the above production method may be spherical and may have an average diameter of 5 탆 or less and 13 탆 or more. By satisfying the above-described numerical range, the cathode material having different particle sizes can be bimodalized, thereby increasing the rolling density and increasing the energy density per unit volume.

Second embodiment

In one embodiment of the present invention, the precursor of the cathode active material for a lithium secondary battery is a precursor of a cathode active material for a lithium secondary battery comprising a metal hydroxide represented by the following Chemical Formula 1, wherein the difference between the Ti concentration of the core and the Ti concentration have.

[Chemical Formula 1]

Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p

M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.

X is any one element selected from the group consisting of F, N, S and P, and w, x, y, z and p satisfy 0 <w? 0.2, 0? X <0.1, 0? Y? Lt; = z &lt; 0.1, 0 &lt; = p &lt; = 0.1, and the Ni mole fraction of the precursor produced from the above formula (1) is 0.8 or more.

The precursor can be divided into a core and an enclosure surrounding the core. 50% of the total volume from the center of the precursor may be the core and may be the outer perimeter from the core to the outermost surface.

Specifically, the Ti concentration of the core may be different from the Ti concentration of the outer region, and the criterion for distinguishing the core from the outer region may be titanium concentration. By weight, less than 50% of the titanium may be present in the core and greater than 50% of the titanium may be present in the enclosure.

Titanium evenly distributed on the core improves the structural stability through oxidation stability of nickel and titanium which exists in the outer region in excess of 50% forms a stable structure layer having a composition different from that of the core, have.

The method for producing a precursor of a cathode active material for a lithium secondary battery according to a second embodiment of the present invention comprises the steps of: obtaining a first precursor by coprecipitation reaction of a nickel raw material and a heterogeneous raw material, and reacting the first precursor with a titanium raw material, To obtain a second precursor which is divided into an outer envelope surrounding the first precursor.

The second precursor has a difference between the Ti concentration of the core and the outer Ti concentration, and includes the metal hydroxide represented by the above formula (1).

First, the nickel raw material and the heterogeneous raw material, the titanium raw material and the solvent are mixed through the coprecipitation reaction, and the mixture is mixed so as to satisfy the stoichiometric ratio. The precipitant may be further mixed. The description of the nickel raw material, the hetero-element raw material, the titanium raw material, the solvent, and the precipitant is superseded by the above description.

The first precursor by the coprecipitation reaction may include a metal hydroxide satisfying the following formula (3).

(3)

Ni _1-xyz M _{1 x} M 2 _y M 3 _z (OH) _2-p X _p

In Formula 3, M1 and M2 are different from each other, and Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, M3 is any one element selected from the group consisting of In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga. It is an element.

X is any one element selected from the group consisting of F, N, S and P, x, y, z and p are 0 <x <0.3, 0? Y? 0.1, 0? Z? ? P? 0.1.

By reacting the first precursor with the titanium raw material, a second precursor is obtained that encloses the core and the core and is divided into an outline.

The second precursor prepared through the reaction of the first precursor with the titanium raw material is divided into a core and a periphery surrounding the core, and the Ti concentration outside the core may be higher than the Ti concentration of the core.

Cathode active material for lithium secondary battery

Third embodiment

In one embodiment of the present invention, the cathode active material for a lithium secondary battery includes a metal oxide represented by the following formula (4).

[Chemical Formula 4]

Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p

In Formula 4, M 1 and M 2 are different from each other, and Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, M3 is any one element selected from the group consisting of In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga. It is an element.

X is any one element selected from the group consisting of F, N, S and P, and w, x, y, z, p and m are each in the range of 0.02? W? 0.2, 0 <x <0.1, 0.3, 0? Z? 0.1, 0? P? 0.1, 0 <m?

The positive electrode active material containing the metal oxide represented by Formula 4 can be obtained by mixing the precursor corresponding to the first embodiment with the lithium source material. m is a value that satisfies 0 < m &lt; = 0.1, the structural instability attributed to Li deficiency may act as a cause of deterioration of the performance of the cathode material. On the other hand, if it exceeds 0.1, m due to increase in surface Li It may be a cause of increase of surface side reaction and decrease of energy density due to reduction of discharge capacity. Therefore, m can be controlled in a range exceeding 0 and not more than 0.1.

Titanium is an element for replacement of manganese and is essentially contained in a cathode active material for a lithium secondary battery according to the present invention. When the molar fraction of titanium is less than 0.02, it may be difficult to expect high-rate characteristics, and excellent lifetime characteristics and high-temperature stability may not be exhibited. Titanium can be evenly distributed in the cathode active material.

Specifically, the composition of the positive electrode active material has a particle diameter of 5 to 20 mu m based on the center particle diameter, and a Li / metal ratio of 1.0% , And 1.1 or less.

The method for producing a cathode active material for a lithium secondary battery according to a third embodiment of the present invention includes the steps of: obtaining a precursor by coprecipitation reaction of a nickel raw material, a titanium raw material, and a heterogeneous raw material to form a precursor; Thereby obtaining a cathode active material represented by the above formula (4).

The step of obtaining the precursor is superseded by the above description of the method for producing the precursor according to the first embodiment.

The precursor and the lithium raw material are mixed. The lithium source material may be mixed with the precursor at a molar ratio of 1.0: 1.0 to 1.1: 1 (lithium source material: precursor). As the lithium source material, a lithium compound such as lithium hydroxide (LiOH), lithium carbonate (LiCO ₃ ) or the like which is generally used in the production of the cathode active material may be used.

Followed by mixing and firing to obtain a cathode active material. In this case, the firing temperature in the oxidizing atmosphere may be 700 ° C. to 850 ° C., and the firing may be performed within 20 hours based on the maintenance interval.

Fourth embodiment

In one embodiment of the present invention, a cathode active material for a lithium secondary battery includes a metal oxide represented by Chemical Formula 4, and the cathode active material includes a core and an outer casing surrounding the core, There is a difference between the Ti concentration and the outer Ti concentration.

[Chemical Formula 4]

Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p

In Formula 4, M 1 and M 2 are different from each other, and Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, M3 is any one element selected from the group consisting of In, Sn, Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga. It is an element.

X is any one element selected from the group consisting of F, N, S and P, and w, x, y, z, p and m are 0 <w? 0.2, 0 <x <0.1, 0? 0.3, 0? Z? 0.1, 0? P? 0.1, 0 <m?

The cathode active material containing the metal oxide represented by the formula (4) can be obtained by mixing the precursor corresponding to the second embodiment with the lithium source material.

However, the cathode active material according to the fourth embodiment may further include a coating layer that may include a core and an outer periphery surrounding the core, and may be bonded to at least a part of the outer surface. Specifically, the outer Ti concentration may be higher than the Ti concentration of the core. The criterion for distinguishing between the core and the enclosure may be the titanium concentration, which may be present in the enclosure in excess of 50% of the total titanium concentration, and the remainder may be present in the core.

As the titanium is concentrated on the outer surface, a structurally stable surface layer is formed due to the influence of the composition and the titanium, and the effect of improving the high temperature stability can be expected.

As a method for producing a cathode active material for a lithium secondary battery according to a fourth embodiment of the present invention, there is a method for producing a cathode active material by reacting a nickel precursor with a titanium raw material to obtain a first precursor by coprecipitation reaction of a nickel precursor and a heterogeneous precursor raw material, And a second precursor separating the core from the first precursor; and mixing and firing the second precursor and the lithium source material to obtain a cathode active material represented by Formula (4).

The step of obtaining the first precursor and the second precursor will be replaced by the above description of the precursor production method according to the second embodiment.

The second precursor is mixed with the lithium source material. The lithium precursor may be mixed with the second precursor in a molar ratio (lithium source material: precursor) of 1: 1 to 1.1: 1. After mixing and firing, a cathode active material is obtained.

In this case, the firing temperature in the oxidized zone may be 700 to 850 ° C, and the firing may be performed within 20 hours based on the maintenance interval.

Alternatively, as another method of manufacturing the cathode active material for a lithium secondary battery according to the fourth embodiment of the present invention, there is provided a method for producing a lithium secondary battery, comprising the steps of: preparing a first precursor by coprecipitation reaction of a nickel raw material and a heterogeneous raw material to form a first precursor, Mixing the raw materials and then firing to obtain a cathode active material represented by the following formula (4).

The step of obtaining the first precursor is superseded by the above description of the first precursor manufacturing method according to the second embodiment.

The first precursor and the lithium raw material are mixed. The lithium precursor may be mixed with the first precursor in a molar ratio (lithium source material: precursor) of 1: 1 to 1.1: 1. As the lithium source material, lithium compounds such as lithium hydroxide (LiOH) and lithium carbonate (LiCO ₃ ) which are generally used in the production of the cathode active material can be used.

Followed by mixing and firing to obtain a cathode active material. In this case, the firing temperature in the oxidizing atmosphere may be 700 to 850 ° C, and the firing may be performed within 20 hours based on the maintenance interval.

When the firing temperature is less than 700 ° C, the discharge capacity and the rate characteristic may not be good due to the unfavorable state in which the crystallization does not proceed properly. If the firing temperature is higher than 850 ° C, the discharge capacity and the rate characteristic may be poor due to an undercurrent state in which crystallization is excessively advanced. Therefore, the firing temperature can be controlled in the range of 700 to 850 占 폚.

Lithium secondary battery

According to another embodiment of the present invention, there is provided a lithium secondary battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode includes a current collector and a positive electrode active material layer formed on the current collector, A lithium secondary battery including a positive electrode active material is provided.

The description related to the positive electrode active material is omitted since it is as described above.

The cathode active material layer may include a binder and a conductive material.

The binder serves to adhere the positive electrode active material particles to each other and to adhere the positive electrode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl Polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-acrylonitrile, styrene-butadiene rubber, Butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, and the like, but not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material can be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, Carbon-based materials such as black and carbon fiber; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The negative electrode includes a current collector and a negative active material layer formed on the current collector, and the negative active material layer includes a negative active material.

The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

As a material capable of reversibly intercalating / deintercalating lithium ions, any carbonaceous anode active material commonly used in lithium ion secondary batteries can be used as the carbonaceous material. Typical examples thereof include crystalline carbon , Amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in the form of amorphous, plate-like, flake, spherical or fibrous type. Examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, fired coke, and the like.

As the lithium metal alloy, a lithium-metal alloy may be selected from the group consisting of lithium, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, An alloy of a selected metal may be used.

As the material capable of doping and dedoping lithium, Si, SiOx (0 <x <2), Si-Y alloy (Y is an alkali metal, an alkali earth metal, a Group 13 element, a Group 14 element, element and an element selected from the group consisting of, Si is not), Sn, SnO _2, Sn-Y (wherein Y is an alkali metal, alkaline earth metals, group 13 elements, group 14 elements, transition metals, rare earth elements And a combination thereof, but not Sn), and at least one of them may be mixed with SiO ₂ . The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Se, Te, Po, and combinations thereof.

Examples of the transition metal oxide include titanium oxide, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, and the like.

The negative electrode active material layer also includes a binder, and may optionally further include a conductive material.

The binder serves to adhere the anode active material particles to each other and to adhere the anode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, Such as polyvinyl chloride, polyvinyl fluoride, polymers comprising ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, Styrene-butadiene rubber, epoxy resin, nylon, and the like may be used, but the present invention is not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material can be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, Carbon-based materials such as black and carbon fiber; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The collector may be selected from the group consisting of a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foil, a polymer substrate coated with a conductive metal, and a combination thereof.

As the current collector, Al may be used, but the present invention is not limited thereto.

The negative electrode and the positive electrode are prepared by mixing an active material, a conductive material and a binder in a solvent to prepare an active material composition, and applying the composition to a current collector. The method of manufacturing the electrode is well known in the art, and therefore, a detailed description thereof will be omitted herein. As the solvent, N-methylpyrrolidone or the like can be used, but it is not limited thereto.

The positive electrode and the negative electrode may be separated by a separator, and the separator may be any as long as it is commonly used in a lithium battery. Particularly, it is preferable to have a low resistance against the ion movement of the electrolyte and an excellent ability to impregnate the electrolyte. For example, a material selected from a glass fiber, a polyester, a Teflon, a polyethylene, a polypropylene, a polytetrafluoroethylene (PTFE), and a combination thereof may be used in the form of a nonwoven fabric or a woven fabric. The separator has a pore diameter of 0.01 to 10 mu m and a thickness of 5 to 300 mu m.

The lithium salt-containing non-aqueous electrolyte is composed of a non-aqueous electrolyte and lithium. As the non-aqueous electrolyte, a non-aqueous electrolyte, a solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, But are not limited to, lactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, Nitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives , Tetrahydrofuran derivatives, ether, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates, silicates and the like of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt may be any of those conventionally used in lithium batteries and may be dissolved in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , _{LiPF 6, LiCF 3 SO 3,} LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, lithium chloro borate, lower aliphatic carboxylic Lithium borate, lithium perborate, lithium tetraborate, lithium imide, and the like.

The lithium battery can be classified into a lithium ion battery, a lithium ion polymer battery, and a lithium polymer battery depending on the type of the separator and the electrolyte used. The lithium battery can be classified into a cylindrical shape, a square shape, a coin shape, a pouch shape, And can be divided into a bulk type and a thin film type. Also, a lithium primary battery and a lithium secondary battery are both possible.

The manufacturing method of these batteries is well known in the art, and thus a detailed description thereof will be omitted.

FIG. 9 schematically shows a typical structure of a lithium battery according to an embodiment of the present invention.

9, the lithium battery 30 includes a positive electrode 23, a negative electrode 22, and a separator 24 disposed between the positive electrode 23 and the negative electrode 22. The positive electrode 23, the negative electrode 22 and the separator 24 described above are wound or folded and accommodated in the battery container 25. Then, an electrolyte is injected into the battery container 25 and sealed with a sealing member 26, thereby completing the lithium battery 30. The battery container 25 may have a cylindrical shape, a rectangular shape, a thin film shape, or the like. The lithium battery may be a lithium ion battery.

The lithium battery is suitable for applications requiring a high capacity, high output and high temperature driving such as an electric vehicle in addition to a conventional cellular phone, a portable computer, and the like, and can be used in combination with a conventional internal combustion engine, a fuel cell, a supercapacitor, A hybrid vehicle or the like. In addition, the lithium battery can be used for all other applications requiring high output, high voltage and high temperature driving.

The initial activation voltage of the lithium secondary battery according to the present invention may be 4.4 to 4.6V.

When the initial activation voltage is less than 4.4V, the lithium source in the structure can not be sufficiently eliminated, so that the discharge capacity and the rate characteristic may not be good. If it exceeds 4.6 V, the lithium source in the structure is excessively desorbed and the structure becomes unstable, so that the discharge capacity and the rate characteristic may not be good. Therefore, the activation voltage can be controlled within the range of 4.4 to 4.6V, preferably 4.5V.

Hereinafter, specific examples of the present invention will be described. However, the following examples are only a concrete example of the present invention, and the present invention is not limited to the following examples.

Example

Example 1

Ni, Co, and Ti sources in the production of a cathode active material having Li _a Ni _b Co _c Ti _d O ₂ (a = 1.00-1.10, b = 0.88, c = 0.08, d = 0.04, b + c + , A hydroxide precursor is synthesized by coprecipitation, LiOH is dry mixed with a Li source, and firing is performed in an oxygen atmosphere to obtain a cathode active material. A coin cell was prepared using the obtained positive electrode active material.

For the electrochemical evaluation, the cathode active material, the binder (polyvinylidene fluoride; PVDF) and the conductive material (Denka black) were mixed in a weight ratio of 94: 3: 3, To prepare a slurry.

The prepared slurry was spread evenly on an aluminum foil, compressed by a roll press, and vacuum-dried in a vacuum oven for 12 hours to prepare a positive electrode. Lithium metal was used as a counter electrode, and 1 mol of LiPF ₆ solution was used as a liquid electrolyte in a mixed solvent of ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 1: 2 as an electrolytic solution. A lithium secondary battery half coin cell of CR2032 standard was prepared.

Example 2

Ni source and Co source in the production of the cathode active material Li _a Ni _b Co _c Ti _d O ₂ (a = 1.00-1.10, b = 0.88, c = 0.08, d = 0.04, b + c + After the hydroxide precursor was synthesized by an immersion method, a separately prepared Ti aqueous solution was added to synthesize a Ti precursor precursor in the outer portion. LiOH 占₂ 2O was mixed as a Li source and calcination was performed in an oxygen atmosphere to obtain a cathode active material. A coin cell is produced using the obtained positive electrode active material.

Example 3

Ni source and Co source in the production of the cathode active material Li _a Ni _b Co _c Ti _d O ₂ (a = 1.00-1.10, b = 0.88, c = 0.08, d = 0.04, b + c + After the hydroxide precursor is synthesized through the impregnation process, LiOH.H ₂ O is used as a Li source, TiO ₂ is used as a Ti source in a dry manner, and firing is performed in an oxygen atmosphere to obtain a cathode active material. A coin cell is produced using the obtained positive electrode active material.

Comparative Example

Example 1 The composition of the Ti in the composition replaced by _{Mn Li a Ni b Co c Mn} d O2 (a = 1.00-1.10, b = 0.88, c = 0.08, d = 0.04, b + c + d = 1.0) of After the precursor is prepared, LiOH.H ₂ O is dry mixed with a Li source and firing is performed in an oxygen atmosphere to obtain a cathode active material. A coin cell is produced using the obtained positive electrode active material.

Electrochemical evaluation results according to initial activation voltage of cathode material

Comparative Examples and Examples were evaluated for battery characteristics while changing the initial activation voltage as shown in Table 1 below.

Item unit 1 ^st charge voltage, V Comparative Example Example 4.3V 4.5V 4.3V 4.5V Activation 0.1C charge mAh / g 227.9 244.2 220.2 246.6 0.1 C discharge mAh / g 207.4 222.9 188.5 224.6 efficiency % 91.0 91.3 85.6 91.1 Cycle 1 time mAh / g 188.9 192.2 169.1 193.9 50 times mAh / g 173.6 174.9 176.5 192.7 efficiency % 91.9 91.0 104.4 99.4

As shown in Table 1, it can be confirmed that the capacity retention ratio is excellent in the case of continuous charge / discharge after the application of the activation voltage of 4.5 V to the comparative example.

As shown in FIG. 2, when the 4.5 V activation voltage is applied, the voltage difference between the 4.2 V and 3.5 V discharge sections of the comparative example It can be seen that the discharge voltage drop phenomenon is confirmed.

Also, as shown in Fig. 3, no structural difference was observed due to excessive replacement of Mn with Ti.

Electrochemical evaluation results according to initial activation voltage of cathode material

The cell characteristics were evaluated while varying the initial activation voltage as shown in Table 2 below.

Item unit 1 ^st charge voltage, V 4.3V 4.4V 4.5V 4.6V Activation 0.1C charge mAh / g 222.2 240.3 248.5 254.5 0.1 C discharge mAh / g 187.9 209.5 222.1 230.5 efficiency % 84.6 87.2 89.4 90.6 C-rate
(~ 4.3V) 0.1 C mAh / g 189.0 206.1 215.4 218.5 0.5 C mAh / g 176.5 192.5 200.5 202.2 1.0 C mAh / g 171.1 186.6 193.8 194.2 2.0C mAh / g 164.8 180.5 187.1 186.5 4.0C mAh / g 156.3 173.6 180.8 178.7 6.0 C mAh / g 149.3 169.1 174.8 172.1 6.0 / 0.1C % 79.0 82.1 81.2 78.8 Cycle 1 time mAh / g - 188.4 193.1 193.8 50 times mAh / g - 191.3 192.2 184.6 efficiency % - 101.5 99.5 95.3

As shown in Table 2 and FIG. 4, when the initial activation voltage was 4.5 V, discharge capacity and rate characteristics were the best. In addition, as shown in Table 2 and FIG. 5, it can be confirmed that when the 1 ^st activation voltage 4.5 V is applied, the capacity retention rate is excellent at the time of continuous charge / discharge.

Electrochemical evaluation results of Ti anode material

The battery characteristics were evaluated while varying the Ti addition amount as shown in Table 3 below. The Li / Metal ratio was 1.03.

Item unit Ti addition amount, mol% 2 3 4 5 Activation 0.1C charge mAh / g 249.1 247.0 249.6 249.7 0.1 C discharge mAh / g 227.6 226.5 220.4 214.3 efficiency % 91.4 91.7 88.3 85.8 C-rate
(~ 4.3V) 0.1 C mAh / g 218.7 217.9 211.7 203.7 0.5 C mAh / g 200.5 202.3 197.1 188.4 1.0 C mAh / g 191.3 194.6 190.7 181.8 2.0C mAh / g 181.4 187.2 183.7 174.8 4.0C mAh / g 169.2 178.9 176.4 167.3 6.0 C mAh / g 159.2 172.6 171.6 161.1 6.0 / 0.1C % 72.8 79.2 81.1 79.1 Cycle 1 time mAh / g 183.2 190.6 191.1 182.1 50 times mAh / g 140.3 168.5 190.1 178.3 efficiency % 76.6 88.4 99.4 97.8

As shown in Table 3 and FIG. 6, it can be confirmed that the battery characteristics are excellent. In addition, it can be confirmed that the life characteristics of the battery are excellent as shown in Table 3 and FIG.

Results of electrochemical characterization by Li / Metal ratio

The battery characteristics were evaluated while varying the Li / metal ratio as shown in Table 4 below.

Item unit Li / Metal ratio 1.00 1.03 1.05 1.07 Activation
(~ 4.5V) 0.1C charge mAh / g 249.6 248.7 248.3 245.2 0.1 C discharge mAh / g 213.4 215.9 217.0 213.6 efficiency % 85.5 86.8 87.4 87.1 Initial Capacity
(~ 4.3V) 0.1C charge mAh / g 199.0 203.7 205.9 202.8 0.1 C discharge mAh / g 199.2 203.8 206.3 203.0 efficiency % 100.1 100.0 100.2 100.1 C-rate 0.5 C mAh / g 182.6 188.2 190.8 186.7 1.0 C mAh / g 175.2 181.3 184.1 179.9 2.0C mAh / g 166.9 173.6 177.0 172.3 4.0C mAh / g 158.2 166.0 169.4 165.1 6.0 C mAh / g 151.6 159.5 163.1 160.4 6.0 / 0.1C % 76.1 78.3 79.1 79.0 Cycle 1 time mAh / g 175.3 181.6 184.5 180.2 50 times mAh / g 167.8 175.8 180.4 176.2 efficiency % 95.7 96.8 97.8 97.8

It can be confirmed that the battery characteristics are excellent as shown in Table 4 and FIG. Also, as shown in Table 4 and FIG. 10, it can be confirmed that the lifetime characteristics of the battery are excellent.

Electrochemical evaluation results according to heat treatment temperature of cathode material

The cell characteristics were evaluated while varying the firing temperature as shown in Table 5 below.

Item unit Firing holding temperature, 750 760 770 780 Activation
(~ 4.5V) 0.1C charge mAh / g 247.0 245.3 257.3 247.9 0.1 C discharge mAh / g 226.7 222.3 222.4 212.7 efficiency % 91.8 90.6 86.4 85.8 Initial Capacity
(~ 4.3V) 0.1C charge mAh / g 219.5 213.9 213.9 201.7 0.1 C discharge mAh / g 217.9 214.0 214.4 202.0 efficiency % 99.3 100.0 100.2 100.1 C-rate 0.5 C mAh / g 202.3 199.4 199.5 186.6 1.0 C mAh / g 194.6 193.0 193.0 180.1 2.0C mAh / g 187.2 186.6 186.0 173.2 4.0C mAh / g 178.9 179.6 178.3 166.1 6.0 C mAh / g 172.6 174.2 173.1 159.8 6.0 / 0.1C % 79.2 81.4 80.7 79.2 Cycle 1 time mAh / g 190.6 192.5 193.2 180.1 50 times mAh / g 135.7 177.0 190.6 176.2 efficiency % 71.2 91.9 98.7 97.8

It can be confirmed that the battery characteristics are excellent as shown in Table 5 and FIG. In addition, it can be confirmed that the lifetime characteristics of the battery are excellent as shown in Table 4 and FIG.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. It will be understood that the invention may be embodied in other specific forms without departing from the spirit or scope of the invention. It is therefore to be understood that the embodiments and / or the examples described above are illustrative in all aspects and not restrictive.

Claims (15)

1. A precursor of a cathode active material for a lithium secondary battery comprising a metal hydroxide represented by the following formula (1).
[Chemical Formula 1]
Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p
(In the formula 1,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z and p are 0 <w? 0.2, 0 <x <0.3, 0? y? 0.1, 0? z? 0.1 and 0? p? The method according to claim 1,
Wherein the precursor comprises a metal hydroxide represented by the following general formula (2).
(2)
Ni _1-wx Co _x Ti _w (OH) _2-p X _p
(In the formula (2)
X is any one element selected from the group consisting of F, N, S, and P,
w, x and p are 0.02 < w? 0.2, 0 < x? 0.2 and 0? p? 1. A precursor of a cathode active material for a lithium secondary battery comprising a metal hydroxide represented by the following formula (1)
Wherein the precursor is divided into a core and an outer periphery surrounding the core, wherein a difference between the Ti concentration of the core and the Ti concentration of the outer periphery is present.
[Chemical Formula 1]
Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p
(In the formula 1,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z and p are 0 <w? 0.2, 0? x <0.3, 0? y? 0.1, 0? z? 0.1 and 0? p? The method of claim 3,
Wherein the Ti concentration of the outer periphery is higher than the Ti concentration of the core. The method of claim 3,
Wherein the Ti concentration of the core is less than 50% based on 100% of the total Ti weight, and the Ti concentration of the outer periphery exceeds 50%. Reacting the nickel raw material and the heteroatom raw material with each other to form a first precursor; And
Reacting the first precursor with a titanium raw material to obtain a core and a second precursor which is enclosed by the outer circumference,
Wherein the second precursor has a difference between a Ti concentration of the core and a Ti concentration of the outer periphery, and includes a metal hydroxide represented by the following formula (1).
[Chemical Formula 1]
Ni _1-wxyz Ti _w M1 _x M 2 _y M 3 _z (OH) _2-p X _p
(In the formula 1,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z and p are 0 <w? 0.2, 0? x <0.3, 0? y? 0.1, 0? z? 0.1 and 0? p? The method according to claim 6,
In the step of obtaining the first precursor,
Wherein the first precursor comprises a metal hydroxide satisfying the following formula (3).
(3)
Ni _1-xyz M _{1 x} M 2 _y M 3 _z (OH) _2-p X _p
(3)
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
x, y, z, and p are 0 <x <0.3, 0? y? 0.1, 0? z? 0.1, and 0? p? A positive electrode active material for a lithium secondary battery comprising a metal oxide represented by the following formula (4).
[Chemical Formula 4]
Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p
(In the formula 4,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z and p are 0 <w? 0.2, 0 <x <0.3, 0? y? 0.1, 0? z? 0.1, 0? p? 0.1 and -0.1? ) A positive electrode active material for a lithium secondary battery comprising a metal oxide represented by the following formula (4)
Wherein the cathode active material includes a core and an outer periphery surrounding the core, wherein a difference between a Ti concentration of the core and a Ti concentration of the outer periphery exists.
[Chemical Formula 4]
Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p
(In the formula 4,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z, p and m are 0 < w? 0.2, 0 <x <0.3, 0? y? 0.1, 0? z? 0.1, 0? p? 0.1 and -0.1? m? .) 10. The method of claim 9,
Wherein the outer Ti concentration is higher than the Ti concentration of the core. Reacting the nickel raw material and the heteroatom raw material with each other to form a first precursor; And
And mixing and firing the first precursor, the lithium source material, and the titanium source material to obtain a cathode active material represented by Formula 4 below.
[Chemical Formula 4]
Li _{1 + m} Ni _1-wxyz Ti _w M1 _x M _{2 y} M _{3 z} O _2-p X _p
(In the formula 4,
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al, and Ti, and at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga.
X is any one element selected from the group consisting of F, N, S, and P,
w, x, y, z, p and m are 0 < w? 0.2, 0 <x <0.3, 0? y? 0.1, 0? z? 0.1, 0? p? 0.1 and -0.1? m? .) 12. The method of claim 11,
In the step of obtaining the first precursor,
Wherein the first precursor comprises a metal hydroxide satisfying the following formula (3).
(3)
Ni _1-xyz M _{1 x} M 2 _y M 3 _z (OH) _2-p X _p
(3)
M1 and M2 are different from each other and each of Co, Mg, Al, Ca, V, Cr, Mn, Fe, Zn, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, And M is at least one element selected from the group consisting of Y, Ba, La, W, Ce, Sm, Gd, Yb, Sr and Ga; and M3 is at least one element selected from the group consisting of Ni, Co, Mn, Al and Ti.
X is any one element selected from the group consisting of F, N, S, and P,
x, y, z and p are 0 <x <0.3, 0? y? 0.1, 0 <z? 0.1 and 0? p? 12. The method of claim 11,
In the step of obtaining the positive electrode active material,
And the firing temperature is 700 to 850 占 폚. anode;
cathode; And
An electrolyte;
Wherein the positive electrode comprises the positive electrode active material for a lithium secondary battery according to any one of claims 8 to 9. 15. The method of claim 14,
Wherein the initial activation voltage is 4.4 to 4.6 V.

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