KR20230011014A - Method for preparation of lithium transition metal oxides for lithium secondary battery - Google Patents

Abstract

The present invention relates to a method for manufacturing lithium transition metal oxide for a lithium secondary battery. According to the present invention, provided is the method, which manufactures the lithium transition metal oxide for the lithium secondary battery by suppressing the formation of cobalt oxide chunk without additional crushing processes for raw materials.

Description

Manufacturing method of lithium transition metal oxide for lithium secondary battery

The present invention relates to a method for preparing a lithium transition metal oxide for a lithium secondary battery.

As power consumption increases along with multifunctionalization of electronic devices, many attempts have been made to increase the capacity of lithium secondary batteries and improve their charging/discharging efficiency.

For example, a positive electrode active material of 80% or more Ni is applied as a positive electrode material to the positive electrode of a lithium secondary battery, and a metal or metal-based negative active material such as SiO, Si or SiC is applied to the negative electrode as a carbon-based negative active material such as natural graphite or artificial graphite. A technique applied with has been proposed.

A negative electrode active material based on metal and metal oxide enables a higher capacity expression than a carbon-based negative electrode active material. However, it is difficult to increase the content of metal and metal oxide in the negative electrode to 15% or more because the negative electrode active material based on metal and metal oxide has a much larger volume change during charging and discharging than graphite. In addition, when metals and metal oxides are added to the negative electrode, irreversible reactions occur during initial charging and discharging, resulting in greater loss of lithium than when a carbon-based negative electrode active material is used. Therefore, when a negative electrode active material based on metal or metal oxide is applied, the amount of lithium lost increases as the capacity of the battery increases, resulting in a greater decrease in initial capacity.

Accordingly, various methods for increasing the capacity of the lithium secondary battery or reducing the irreversible capacity have been studied. One of them is prelithiation, a concept that replenishes the lithium consumed in the formation of the solid electrolyte interphase layer (SEI) in the initial state in the battery.

Various methods have been proposed for pre-lithiation in batteries.

For example, it is a method of electrochemically lithiation of a negative electrode before driving the battery. However, the lithiated negative electrode is very unstable in the air, and the electrochemical lithiation method has difficulty in scale-up the process.

Another example is a method of coating a negative electrode with lithium metal or lithium silicide (Li _x Si) powder. However, since the powder has high reactivity and deteriorates atmospheric stability, it is difficult to establish a suitable solvent and process conditions when coating the negative electrode.

As a method of preliminary lithiation at the cathode, there is a method of coating more cathode materials according to the amount of lithium consumed in the anode. However, due to the low capacity of the positive electrode material itself, the amount of the added positive electrode material increases, and the energy density and capacity per weight of the final battery decrease by the increased amount of the positive electrode material.

Therefore, a material suitable for preliminary lithiation of a battery in the cathode must have irreversible characteristics in which lithium is desorbed at least twice as much as conventional cathode materials during the first charge and does not react with lithium during subsequent discharge. Additives satisfying these conditions are called sacrificial positive electrode materials.

In the case of a commercial battery, after injecting an electrolyte into a case including a stacked cathode, separator, and anode, a formation process of first charging/discharging is performed. In this process, an SEI layer formation reaction occurs on the anode, and gas is generated due to decomposition of the electrolyte. In the formation process, the sacrificial cathode material releases lithium and decomposes to react with the electrolyte, and gases such as N ₂ , O ₂ , and CO ₂ generated in the process are recovered through a gas pocket removal process.

As the sacrificial cathode material, over-lithiated positive electrode materials, which are metal oxides rich in lithium, are widely used. As the over-lithiated positive electrode materials, anti-fluorite structures such as Li ₆ CoO ₄ , Li ₅ FeO ₄ and Li ₆ MnO ₄ are well known. Their theoretical capacities are 977 mAh/g for Li ₆ CoO ₄ , 867 mAh/g for Li ₅ FeO ₄ , and 1001 mAh/g for Li ₆ MnO ₄ , which are enough to be used as sacrificial cathode materials. Among them, Li ₆ CoO ₄ has the highest electrical conductivity and has good electrochemical properties for use as a sacrificial anode material.

As Li ₆ CoO ₄ is desorbed and decomposed step by step in the formation process, the crystal phase collapses, and O ₂ gas is inevitably generated during this process. In an ideal case, Li ₆ CoO ₄ should not generate additional gas during charge/discharge cycles after the formation process. If gas is constantly generated during charging and discharging, the pressure inside the battery increases, and the distance between the electrodes increases, and the battery capacity and energy density may decrease. In severe cases, the battery may not withstand the pressure and explode, resulting in an explosion accident.

Therefore, there is a demand for developing a technology capable of inactivating or stabilizing the final crystalline phase of Li ₆ CoO ₄ so that it has no electrochemical activity so that no additional gas is generated during charge and discharge cycles.

Meanwhile, in order to synthesize the sacrificial cathode material by a solid-state reaction method, CoO is required as a raw material, and in order to obtain CoO, Co ₃ O ₄ must be reduced through heat treatment at a high temperature. However, in the high-temperature heat treatment process, very hard chunks are formed by growth and aggregation of CoO particles. Since cobalt oxide chunks cannot be applied as they are in the process of manufacturing lithium transition metal oxide, a mechanical crushing process for breaking the chunks is additionally required.

The present invention is to provide a method for producing a lithium transition metal oxide for a lithium secondary battery without an additional crushing process for raw materials by suppressing the formation of the cobalt oxide chunks.

Hereinafter, a method for manufacturing a lithium transition metal oxide for a lithium secondary battery according to an embodiment of the present invention will be described in more detail.

Terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the invention based on the principle that

Unless defined otherwise herein, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms used in the description in the present invention are merely to effectively describe specific embodiments and are not intended to limit the present invention.

As used herein, the singular forms also include the plural forms unless the phrases clearly dictate the contrary.

As used herein, the meaning of "comprising" specifies a particular characteristic, region, integer, step, operation, element, and/or component, and other specific characteristics, regions, integers, steps, operations, elements, elements, and/or groups. does not exclude the presence or addition of

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, this is not intended to limit the present invention to a particular disclosed form, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope.

In this specification, for example, when the positional relationship between the two parts is described as 'on ~', 'on ~ on', 'on ~ below', 'next to', etc., 'immediately' or 'directly' Unless an expression is used, one or more other parts may be placed between two parts.

In this specification, for example, when a temporal precedence relationship is described as 'after', 'following', 'after', 'before', etc., the expression 'immediately' or 'directly' is not used. It may also include non-continuous cases.

In this specification, the term 'at least one' should be understood to include all possible combinations from one or more related items.

The term "cathode additive" used herein refers to a material having irreversible characteristics in which lithium is desorbed at least twice as much as conventional cathode materials during initial charging of a battery and does not react with lithium during subsequent discharging. The positive electrode additive may also be referred to as sacrificial positive electrode materials. Since the positive electrode additive compensates for the loss of lithium, the capacity of the battery is increased by recovering the lost capacity of the battery as a result, and the life characteristics and safety of the battery are improved by suppressing gas generation and preventing the battery from exploding. can be improved

In general, lithium cobalt oxide doped with a different element can be obtained by a method in which lithium oxide, cobalt oxide, and an oxide of a different element are mixed in a solid state and calcined under an inert atmosphere.

In the synthesis using such a solid-state reaction method, CoO is required as the cobalt compound. CoO can be obtained by reducing Co ₃ O ₄ by heat treatment at high temperature. However, in the high-temperature heat treatment process, very hard chunks are formed by growth and aggregation of CoO particles. Since the chunks are large and hard, the reaction efficiency of the solid phase reaction method is greatly reduced. Accordingly, processes for mechanically crushing and classifying the chunks are additionally required, which increases the cost of raw materials for producing lithium transition metal oxide.

By the way, as a result of continuous research by the present inventors, when cobalt oxide (Co ₃ O ₄ ) is doped with a heterogeneous element, grain growth of cobalt oxide is suppressed, thereby producing doped cobalt oxide that can be used as a raw material without an additional crushing process. It was confirmed that it can be obtained. Accordingly, a lithium transition metal oxide usable as a sacrificial cathode material for a lithium secondary battery can be more easily prepared by reacting the doped cobalt oxide with lithium oxide.

According to one embodiment of the invention,

heat-treating a mixture of cobalt oxide and the oxide of a different element under an inert atmosphere at a temperature of 900° C. to 1100° C. for 4 to 10 hours to obtain cobalt oxide doped with a different element; and

Obtaining lithium cobalt oxide doped with a different element by heat-treating the mixture of cobalt oxide and lithium oxide doped with the different element under an inert atmosphere and at a temperature of 500 ° C to 700 ° C for 1 hour to 15 hours

Including, there is provided a method for producing a lithium transition metal oxide for a lithium secondary battery.

First, a step of heat-treating a mixture of cobalt oxide and an oxide of a different element to obtain cobalt oxide doped with a different element is performed.

In the step of obtaining the cobalt oxide doped with the heterogeneous element, the cobalt oxide may be Co ₃ O ₄ .

The hetero-element oxide may include at least one element selected from the group consisting of a Group 2 element, a Group 13 element, a Group 14 element, a 4th period transition metal, a 5th period transition metal, and a 6th period transition metal.

Specifically, the Group 2 element includes at least one selected from the group consisting of Mg, Ca, Sr, and Ba; The Group 13 element includes at least one selected from the group consisting of Al, Ga, and In; The Group 14 element includes at least one selected from the group consisting of Si, Ge, and Sn; the 4th period transition metal includes at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; the 5th period transition metal includes at least one selected from the group consisting of Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd; The 6-period transition metal includes at least one selected from the group consisting of Lu, Hf, Ta, W, Re, Os, Ir, Pt, and Au.

Preferably, in terms of ease of alloying or doping with cobalt oxide and stabilization of the crystal phase, the hetero-element oxide includes at least one element selected from the group consisting of Zn, Al, Mg, Ti, Zr, Nb, and W. can do. Zn, Al, Mg, Ti, Zr, Nb, and W are well substituted for Co sites in the lattice structure of anti-fluorite, a crystal phase of Li ₆ CoO ₄ , but their oxidation numbers do not change. For example, Zn has a Li ₆ ZnO ₄ crystalline phase, can easily form an alloy with Li ₆ CoO ₄ , and since its oxidation number does not change at 2+, it can effectively suppress the oxidation of Co ⁴⁺ cations after initial charging. can

More preferably, the hetero-element oxide may include one or more elements selected from the group consisting of Zn, Al, and Mg.

The mixture of the cobalt oxide and the oxide of the heterogeneous element may include 70 mol% to 80 mol% of cobalt and 20 mol% to 30 mol% of the heteroelement.

Specifically, the mixture may contain 70 mol% or more, or 73 mol% or more; and 80 mol% or less, or 75 mol% or less of cobalt. 20 mol% or more, or 25 mol% or more; And it may contain 30 mol% or less, or 27 mol% or less of the heterogeneous element.

In order to ensure the performance of the battery while suppressing the growth of particles of cobalt oxide, the mixture preferably contains 80 mol% or less of cobalt and 20 mol% or more of the heterogeneous element in a molar ratio. However, if the molar ratio of the heterogeneous elements is too high, the heterogeneous elements may not be dissolved in the CoO lattice, so that a single phase may not be formed and may become heterogeneous. Therefore, the mixture preferably contains 70 mol% or more of cobalt and 30 mol% or less of the heterogeneous element in a molar ratio.

Preferably, the mixture of the cobalt oxide and the hetero-element oxide comprises 70 mol% to 80 mol%, alternatively 70 mol% to 75 mol%, alternatively 73 mol% to 75 mol% of cobalt; In addition, the cobalt oxide and the hetero element oxide may be included in a molar ratio of 20 mol% to 30 mol%, or 20 mol% to 27 mol%, or 25 mol% to 27 mol% of the heterogeneous element.

The heat treatment of the mixture of the cobalt oxide and the hetero-element oxide may be performed under an inert atmosphere formed using an inert gas such as Ar, N ₂ , Ne, and He.

In addition, the heat treatment of the mixture of the cobalt oxide and the hetero-element oxide may be performed under the inert atmosphere and at a temperature of 900 °C to 1100 °C.

The heat treatment temperature is preferably 900° C. or higher, or 950° C. or higher, so that crystal seeds can be generated at an appropriate rate and doping of a different type of element into the cobalt oxide. However, when the heat treatment temperature is excessively high, grown crystal particles may form very hard chunks by aggregation, or different elements may be phase separated into secondary phases. Therefore, the heat treatment temperature is preferably 1100°C or less, or 1050°C or less, or 1000°C or less.

Specifically, in the step of obtaining the cobalt oxide doped with the heterogeneous element, the heat treatment temperature may be 900 °C to 1100 °C, or 950 °C to 1100 °C, or 950 °C to 1050 °C, or 950 °C to 1000 °C.

In addition, the heat treatment of the mixture of the cobalt oxide and the hetero-element oxide may be performed for 4 hours to 10 hours under the inert atmosphere and the temperature. The heat treatment time may be adjusted in consideration of the time required for crystal stabilization by introduction of the heterogeneous element into cobalt oxide in the form of an alloy or doping. Specifically, the heat treatment time is 4 hours or more, or 5 hours or more; and may be 10 hours or less, or 8 hours or less, or 6 hours or less. Preferably, the heat treatment time may be 4 to 10 hours, or 4 to 8 hours, or 4 to 6 hours, or 5 to 6 hours.

Through the above method, cobalt oxide doped with the heterogeneous element may be obtained.

The cobalt oxide doped with the heterogeneous element may be a particle having a particle size of 1 μm to 100 μm. Here, the particle size means the particle size of the cobalt oxide doped with the heterogeneous element obtained through the method without a separate crushing process. The particle size may be measured using a laser diffraction scattering type particle size distribution analyzer for the cobalt oxide doped with the heterogeneous element, a scanning electron microscope, or a particle classifier.

Preferably, 95% or more or 98% or more of the cobalt oxide doped with a different element obtained in the above step may be particles having a particle size of 38 μm or less. That is, when the cobalt oxide doped with a different element obtained in the above step is applied to a sieve having a sieve opening of 38 μm or a sieve having a Taylor screen of 400 mesh, based on the total weight It can pass through the sieve with a yield of 95% or more or 98% or more.

Then, heat-treating the mixture of the cobalt oxide doped with the different element and the lithium oxide to obtain the lithium cobalt oxide doped with the different element is performed.

In the step of obtaining the lithium cobalt oxide doped with the heterogeneous element, as the lithium oxide, an oxide containing lithium such as Li ₂ O may be used without particular limitation.

In the step of obtaining the lithium cobalt oxide doped with the different element, the mixture may be prepared by mixing the cobalt oxide doped with the different element obtained in the previous step and the lithium oxide.

Preferably, the mixture may include the cobalt oxide doped with the heterogeneous element and the lithium oxide in a molar ratio of 2 to 4 times that of lithium relative to the sum of the molar numbers of cobalt and the heterogeneous element.

In order to ensure battery performance, the mixture preferably includes the cobalt oxide doped with the heterogeneous element and the lithium oxide in a molar ratio of at least two times that of lithium relative to the sum of the molar numbers of cobalt and the heterogeneous element. In addition, in order to express the stabilizing effect of the crystal phase according to the introduction of the heterogeneous element, the mixture is composed of the cobalt oxide doped with the heterogeneous element and the lithium oxide, compared to the sum of the moles of cobalt and the heterogeneous element, lithium 4 It is preferable to include so that the molar ratio is less than twice.

Specifically, the mixture contains lithium twice or more, or 2.5 times or more; And it may have the molar ratio of 4 times or less, or 3.5 times or less, or 3 times or less. More preferably, the mixture may have a molar ratio of 2 to 3.5 times, 2.5 to 3.5 times, or 2.5 to 3 times of lithium with respect to the sum of the moles of cobalt and the heterogeneous element.

The heat treatment of the mixture of the cobalt oxide doped with the heterogeneous element and the lithium oxide may be performed under an inert atmosphere formed using an inert gas such as Ar, N ₂ , Ne, and He.

In addition, the heat treatment of the mixture of cobalt oxide doped with a different element and the lithium oxide may be performed under the inert atmosphere and at a temperature of 500 °C to 700 °C.

In order to generate crystal seeds at an appropriate rate, the heat treatment temperature is preferably 500 °C or higher, or 550 °C or higher. However, when the heat treatment temperature is excessively high, sintering may occur in which grown crystal particles are aggregated. Therefore, the heat treatment temperature is preferably 700°C or less, or 650°C or less, or 600°C or less.

Specifically, in the step of obtaining the lithium cobalt oxide doped with the heterogeneous element, the heat treatment temperature may be 500 °C to 700 °C, or 550 °C to 700 °C, or 550 °C to 650 °C, or 550 °C to 600 °C. .

And, heat treatment of the mixture of the cobalt oxide doped with a different element and the lithium oxide may be performed for 1 hour to 15 hours under the inert atmosphere and the temperature. The heat treatment time may be adjusted in consideration of the time required for crystal stabilization by introduction of the heterogeneous element into the lithium transition metal oxide in the form of an alloy or doping. Specifically, the heat treatment time is 1 hour or more, or 2 hours or more; and 15 hours or less, or 14 hours or less, or 12 hours or less. Preferably, the heat treatment time may be 2 hours to 15 hours, or 2 hours to 14 hours, or 2 hours to 12 hours.

Lithium cobalt oxide doped with the heterogeneous element may be obtained through the above method.

For example, the lithium cobalt oxide doped with the heterogeneous element may be a compound represented by Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3 below:

[Formula 1]

Li ₆ Co _1-x M ¹ _x O ₄

In Formula 1,

M ¹ is at least one element selected from the group consisting of a Group 2 element, a Group 13 element, a Group 14 element, a 4th period transition metal, a 5th period transition metal, and a 6th period transition metal;

x is from 0.05 to 0.80;

[Formula 2]

Li ₆ Co _1-xy Zn _x M ² _y O ₄

In Formula 1,

M ² is a Group 2 element, a Group 13 element, a Group 14 element, a Period 5 transition metal, or a Period 6 transition metal;

x is from 0.1 to 0.7;

y is from 0.01 to 0.1;

[Formula 3]

Li ₆ Co _1-xyz Zn _x Zr _y M ³ _z O ₄

In Formula 3,

M ³ is a Group 2 element, a Group 13 element, a Group 14 element, or a Period 6 transition metal;

x is from 0.1 to 0.7;

y is from 0.01 to 0.05;

z is from 0.01 to 0.1.

In Chemical Formulas 1 to 3, M ¹ , M ² and M ³ are each a heterogeneous element.

Preferably, M ¹ is at least one element selected from the group consisting of a Group 2 element, a Group 13 element, a Group 14 element, a 4th period transition metal, a 5th period transition metal, and a 6th period transition metal. M ² is a Group 2 element, a Group 13 element, a Group 14 element, a 5th period transition metal, or a 6th period transition metal. M ³ is a Group 2 element, a Group 13 element, a Group 14 element, or a 6th period transition metal.

Specifically, the Group 2 element includes at least one selected from the group consisting of Mg, Ca, Sr, and Ba; The Group 13 element includes at least one selected from the group consisting of Al, Ga, and In; The Group 14 element includes at least one selected from the group consisting of Si, Ge, and Sn; the 4th period transition metal includes at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn; the 5th period transition metal includes at least one selected from the group consisting of Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd; The 6-period transition metal includes at least one selected from the group consisting of Lu, Hf, Ta, W, Re, Os, Ir, Pt, and Au.

More preferably, M ¹ may include one or more elements selected from the group consisting of Zn, Al, Mg, Ti, Zr, Nb, and W. The M ² may include an element such as Al, Mg, Ti, Zr, Nb, or W. And, the M ³ may include an element of Al, Mg, Nb, or W.

In Formula 1, x is 0.05 to 0.80. Specifically, the x is 0.05 or more, or 0.10 or more, or 0.15 or more; And it may be 0.80 or less, or 0.70 or less, or 0.60 or less. Preferably, x may be 0.10 to 0.80, or 0.10 to 0.70, or 0.15 to 0.70, or 0.15 to 0.60.

In Formula 2, x is 0.1 to 0.7, and y is 0.01 to 0.1.

Specifically, in Formula 2, x is 0.1 or more, or 0.15 or more, or 0.2 or more; And it may be 0.7 or less, or 0.5 or less, or 0.3 or less. Preferably, x may be 0.1 to 0.7, alternatively 0.15 to 0.7, alternatively 0.15 to 0.5, alternatively 0.2 to 0.5, alternatively 0.2 to 0.3.

In Formula 2, y is 0.01 or more, or 0.02 or more, or 0.03 or more; And it may be 0.1 or less, or 0.07 or less, or 0.05 or less. Preferably, the y may be 0.01 to 0.1, alternatively 0.02 to 0.1, alternatively 0.02 to 0.07, alternatively 0.03 to 0.07, alternatively 0.03 to 0.05.

In Formula 3, x is 0.1 or more, or 0.15 or more, or 0.2 or more; And it may be 0.7 or less, or 0.5 or less, or 0.3 or less. Preferably, x may be 0.1 to 0.7, alternatively 0.15 to 0.7, alternatively 0.15 to 0.5, alternatively 0.2 to 0.5, alternatively 0.2 to 0.3.

In Formula 3, y is 0.01 or more; And it may be 0.05 or less, or 0.03 or less. Preferably, x may be 0.01 to 0.05, or 0.01 to 0.03.

In Formula 3, z is 0.01 or more or 0.03 or more; And it may be 0.1 or less, or 0.08 or less, or 0.05 or less. Preferably, z may be 0.01 to 0.1, or 0.01 to 0.08, or 0.03 to 0.08, or 0.03 to 0.05.

Preferably, the lithium cobalt oxide doped with the heterogeneous element is Li ₆ Co _0.95 Zn _0.05 O ₄ , Li ₆ Co _0.9 Zn _0.1 O ₄ , Li ₆ Co _0.85 Zn _0.15 O ₄ , Li ₆ Co _0.8 Zn _0.2 O ₄ , Li ₆ Co _0.75 Zn _0.25 O ₄ , Li ₆ Co _0.7 Zn _0.3 O ₄ , Li ₆ Co _0.65 Zn _0.35 O ₄ , Li ₆ Co _0.6 Zn _0.4 O ₄ , Li ₆ Co _0.55 Zn _0.45 O ₄ , Li ₆ Co _0.5 Zn _0.5 O ₄ , Li ₆ Co _0.45 Zn _0.55 O ₄ , Li ₆ Co _0.4 Zn _0.6 O ₄ , Li ₆ Co _0.35 Zn _0.65 O ₄ , Li ₆ Co _0.3 Zn _0.7 O ₄ , Li ₆ Co _0.25 Zn _0.75 O ₄ , Li ₆ Co _0.2 Zn _0.8 O ₄ ; Li ₆ Co _0.95 Al _0.05 O ₄ , Li ₆ Co _0.9 Al _0.1 O ₄ , Li ₆ Co _0.85 Al _0.15 O ₄ , Li ₆ Co _0.8 Al _0.2 O ₄ , Li ₆ Co _0.75 Al _0.25 O ₄ , Li ₆ Co _0.7 Al _0.3 O ₄ , Li ₆ Co _0.65 Al _0.35 O ₄ , Li ₆ Co _0.6 Al _0.4 O ₄ , Li ₆ Co _0.55 Al _0.45 O ₄ , Li ₆ Co _0.5 Al _0.5 O ₄ , Li ₆ Co _0.45 Al _0.55 O ₄ , Li ₆ Co _0.4 Al _0.6 O ₄ , Li ₆ Co _0.35 Al _0.65 O ₄ , Li ₆ Co _0.3 Al _0.7 O ₄ , Li ₆ Co _0.25 Al _0.75 O ₄ , Li ₆ Co _0.2 Al _0.8 O ₄ ; Li ₆ Co _0.95 Mg _0.05 O ₄ , Li ₆ Co _0.9 Mg _0.1 O ₄ , Li ₆ Co _0.85 Mg _0.15 O ₄ , Li ₆ Co _0.8 Mg _0.2 O ₄ , Li ₆ Co _0.75 Mg _0.25 O ₄ , Li ₆ Co _0.7 Mg _0.3 O ₄ , Li ₆ Co _0.65 Mg _0.35 O ₄ , Li ₆ Co _0.6 Mg _0.4 O ₄ , Li ₆ Co _0.55 Mg _0.45 O ₄ , Li ₆ Co _0.5 Mg _0.5 O ₄ , Li ₆ Co _0.45 Mg _0.55 O ₄ , Li ₆ Co _0.4 Mg _0.6 O ₄ , Li ₆ Co _0.35 Mg _0.65 O ₄ , Li ₆ Co _0.3 Mg _0.7 O ₄ , Li ₆ Co _0.25 Mg _0.75 O ₄ , Li ₆ Co _0.2 Mg _0.8 O ₄ ; Li ₆ Co _0.95 Ti _0.05 O ₄ , Li ₆ Co _0.9 Ti _0.1 O ₄ , Li ₆ Co _0.85 Ti _0.15 O ₄ , Li ₆ Co _0.8 Ti _0.2 O ₄ , Li ₆ Co _0.75 Ti _0.25 O ₄ , Li ₆ Co _0.7 Ti _0.3 O ₄ , Li ₆ Co _0.65 Ti _0.35 O ₄ , Li ₆ Co _0.6 Ti _0.4 O ₄ , Li ₆ Co _0.55 Ti _0.45 O ₄ , Li ₆ Co _0.5 Ti _0.5 O ₄ , Li ₆ Co _0.45 Ti _0.55 O ₄ , Li ₆ Co _0.4 Ti _0.6 O ₄ , Li ₆ Co _0.35 Ti _0.65 O ₄ , Li ₆ Co _0.3 Ti _0.7 O ₄ , Li ₆ Co _0.25 Ti _0.75 O ₄ , Li ₆ Co _0.2 Ti _0.8 O ₄ ; Li ₆ Co _0.95 Zr _0.05 O ₄ , Li ₆ Co _0.9 Zr _0.1 O ₄ , Li ₆ Co _0.85 Zr _0.15 O ₄ , Li ₆ Co _0.8 Zr _0.2 O ₄ , Li ₆ Co _0.75 Zr _0.25 O ₄ , Li ₆ Co _0.7 Zr _0.3 O ₄ , Li ₆ Co _0.65 Zr _0.35 O ₄ , Li ₆ Co _0.6 Zr _0.4 O ₄ , Li ₆ Co _0.55 Zr _0.45 O ₄ , Li ₆ Co _0.5 Zr _0.5 O ₄ , Li ₆ Co _0.45 Zr _0.55 O ₄ , Li ₆ Co _0.4 Zr _0.6 O ₄ , Li ₆ Co _0.35 Zr _0.65 O ₄ , Li ₆ Co _0.3 Zr _0.7 O ₄ , Li ₆ Co _0.25 Zr _0.75 O ₄ , Li ₆ Co _0.2 Zr _0.8 O ₄ ; Li ₆ Co _0.95 Nb _0.05 O ₄ , Li ₆ Co _0.9 Nb _0.1 O ₄ , Li ₆ Co _0.85 Nb _0.15 O ₄ , Li ₆ Co _0.8 Nb _0.2 O ₄ , Li ₆ Co _0.75 Nb _0.25 O ₄ , Li ₆ Co _0.7 Nb _0.3 O ₄ , Li ₆ Co _0.65 Nb _0.35 O ₄ , Li ₆ Co _0.6 Nb _0.4 O ₄ , Li ₆ Co _0.55 Nb _0.45 O ₄ , Li ₆ Co _0.5 Nb _0.5 O ₄ , Li ₆ Co _0.45 Nb _0.55 O ₄ , Li ₆ Co _0.4 Nb _0.6 O ₄ , Li ₆ Co _0.35 Nb _0.65 O ₄ , Li ₆ Co _0.3 Nb _0.7 O ₄ , Li ₆ Co _0.25 Nb _0.75 O ₄ , Li ₆ Co _0.2 Nb _0.8 O ₄ ; Li ₆ Co _0.95 W _0.05 O ₄ , Li ₆ Co _0.9 W _0.1 O ₄ , Li ₆ Co _0.85 W _0.15 O ₄ , Li ₆ Co _0.8 W _0.2 O ₄ , Li ₆ Co _0.75 W _0.25 O ₄ , Li ₆ Co _0.7 W _0.3 O ₄ , Li ₆ Co _0.65 W _0.35 O ₄ , Li ₆ Co _0.6 W _0.4 O ₄ , Li ₆ Co _0.55 W _0.45 O ₄ , Li ₆ Co _0.5 W _0.5 O ₄ , Li ₆ Co _0.45 W _0.55 O ₄ , Li ₆ Co _0.4 W _0.6 O ₄ , Li ₆ Co _0.35 W _0.65 O ₄ , Li ₆ Co _0.3 W _0.7 O ₄ , Li ₆ Co _0.25 W _0.75 O ₄ , Li ₆ Co _0.2 W _0.8 O ₄ , Li ₆ Co _0.77 Zn _0.2 Al _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Al _0.04 O ₄ , Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ , Li ₆ Co _0.75 Zn _0.2 Al _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Al _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Al _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Al _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Mg _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Mg _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Mg _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Mg _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Mg _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Mg _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Ti _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Ti _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Ti _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Ti _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 T i _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Ti _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Zr _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Zr _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Zr _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Zr _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Zr _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Zr _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Nb _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Nb _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Nb _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Nb _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Nb _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Nb _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 W _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 W _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 W _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 W _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 W _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 W _0.05 O ₄ , Li ₆ Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Mg _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Nb _{0.05 Zr} O ₄ , Li ₆ Co _0.69 Zn _0.25 W _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Al _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _0.25 Mg _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _{0.25 Nb} Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _0.25 W _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Al _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 Mg _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 Nb _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 W _0.05 Zr _{4 0.01} Li ₆ Co _0.64 Zn _0.3 Al _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Mg _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Nb _0.03 Zr _0.03 O ₄ , or Li ₆ Co _0.64 Zn _0.3 W _{0.03 Zr} may be O ₄ .

The lithium transition metal oxide obtained by the above-described method has a property of releasing lithium irreversibly during charging and discharging of a lithium secondary battery. Therefore, the lithium transition metal oxide may be included in a positive electrode for a lithium secondary battery and serve as a sacrificial positive electrode material for prelithiation. In particular, the lithium transition metal oxide can minimize side reactions with the electrolyte, thereby suppressing gas generation at the positive electrode during charging and discharging of the lithium secondary battery. Therefore, the positive electrode additive for a lithium secondary battery including the lithium transition metal oxide can improve safety and lifespan characteristics of the lithium secondary battery.

According to another embodiment of the present invention, a cathode for a lithium secondary battery is provided.

The cathode for a lithium secondary battery may include a cathode active material, a binder, a conductive material, and the lithium transition metal oxide.

Preferably, the positive electrode for a lithium secondary battery includes a positive electrode material including a positive electrode active material, a conductive material, the lithium transition metal oxide, and a binder; And, a current collector supporting the positive electrode material is included.

According to one embodiment, the lithium transition metal oxide may be included in an amount greater than 0 wt% and less than 15 wt% based on the total weight of the positive electrode material.

In order to compensate for irreversible lithium consumed in the formation of the SEI layer, the content of the lithium transition metal oxide is preferably greater than 0% by weight based on the total weight of the positive electrode material. However, when the lithium transition metal oxide, which is a sacrificial cathode material, is included in an excessive amount, the content of the cathode active material exhibiting reversible charge/discharge capacity is reduced, thereby reducing the capacity of the battery, and the remaining lithium in the battery is plated on the negative electrode, thereby improving the battery performance. It may cause a short circuit or impair safety. Therefore, the content of the lithium transition metal oxide is preferably 15% by weight or less based on the total weight of the positive electrode material.

Specifically, the content of the lithium transition metal oxide is greater than 0 wt%, or 0.5 wt% or more, or 1 wt% or more, or 2 wt% or more, or 3 wt% or more based on the total weight of the positive electrode material; And, it may be 15% by weight or less, or 12% by weight or less, or 10% by weight or less. Preferably, the content of the lithium transition metal oxide is 0.5 wt% to 15 wt%, alternatively 1 wt% to 15 wt%, alternatively 1 wt% to 12 wt%, or 2 wt% to 12 wt%, based on the total weight of the positive electrode material. % by weight, alternatively 2% to 10% by weight, alternatively 3% to 10% by weight.

Compounds known to be applicable to lithium secondary batteries in the art to which the present invention pertains may be used as the cathode active material without particular limitation.

As a non-limiting example, the cathode active material is NCM (Li[Ni,Co,Mn]O ₂ ), NCMA (Li[Ni,Co,Mn,Al]O ₂ ), LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₂ , LiNi _1-d Co _d O ₂ , LiCo _1-d Mn _d O ₂ , LiNi _1-d Mn _d O ₂ (0≤d＜1 in the above), Li(Ni _a Co _b Mn _c )O ₄ (0<a<2, 0<b<2, 0<c<2, a+b+c=2), LiMn _2-e Ni _e O ₄ , LiMn _2-e Co _e O ₄ (ideal 0 < e < 2), LiCoPO ₄ , and LiFePO ₄ . As the cathode active material, one or a mixture of two or more of the above examples may be used.

According to one embodiment, the positive electrode active material may be included in 80% to 98% by weight based on the total weight of the positive electrode material.

Specifically, the content of the positive electrode active material is 80% by weight or more, or 82% by weight or more, or 85% by weight or more based on the total weight of the positive electrode material; And, it may be 98% by weight or less, or 95% by weight or less, or 93% by weight or less, or 90% by weight or less.

Preferably, the content of the cathode active material is 82 wt% to 98 wt%, or 82 wt% to 95 wt%, or 82 wt% to 93 wt%, or 85 wt% to 93 wt%, based on the total weight of the cathode material. , or 85% to 90% by weight.

The conductive material is used to impart conductivity to the electrode.

As the conductive material, any material having electronic conductivity without causing chemical change of the battery may be used without particular limitation. As a non-limiting example, the conductive material may include carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; graphite such as natural graphite and artificial graphite; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives. As the conductive material, one or a mixture of two or more of the above examples may be used.

The content of the conductive material may be adjusted within a range that does not cause a decrease in capacity of the battery while exhibiting an appropriate level of conductivity. Preferably, the content of the conductive material may be 0.5 wt% to 10 wt%, or 1 wt% to 10 wt%, or 1 wt% to 5 wt%, based on the total weight of the positive electrode material.

The binder is used to properly attach the positive electrode material to the current collector.

As a non-limiting example, the binder is polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer (PVdF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl Cellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluoro rubber, and the like. As the binder, one or a mixture of two or more of the above examples may be used.

The content of the binder may be adjusted within a range that does not cause a decrease in battery capacity while exhibiting an appropriate level of adhesiveness. Preferably, the content of the binder may be 0.5 wt% to 10 wt%, 1 wt% to 10 wt%, or 1 wt% to 5 wt%, based on the total weight of the positive electrode material.

As the current collector, a material known in the art to be applicable to a cathode of a lithium secondary battery may be used without particular limitation.

As a non-limiting example, the current collector may include stainless steel; aluminum; nickel; titanium; calcined carbon; Alternatively, aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. may be used.

Preferably, the current collector may have a thickness of 3 μm to 500 μm. In order to increase adhesion of the positive electrode material, the current collector may have fine irregularities formed on its surface. The current collector may have various forms such as film, sheet, foil, net, porous material, foam, and non-woven fabric.

The cathode for a lithium secondary battery may be formed by stacking a cathode material including the cathode active material, the conductive material, the lithium transition metal oxide, and a binder on the current collector.

According to another embodiment of the invention, the positive electrode for the lithium secondary battery; cathode; separator; And, a lithium secondary battery including an electrolyte is provided.

The lithium secondary battery includes a positive electrode including the lithium transition metal oxide or the positive electrode additive for a lithium secondary battery. Accordingly, the lithium secondary battery may suppress generation of gas at the positive electrode of the charge/discharge battery, and may exhibit improved safety and lifespan characteristics. In addition, the lithium secondary battery may exhibit high discharge capacity, excellent output characteristics, and capacity retention rate.

Accordingly, the lithium secondary battery is used in portable electronic devices such as mobile phones, notebook computers, tablet computers, mobile batteries, and digital cameras; And it can be used as an energy supply source with improved performance and safety in the field of transportation means such as electric vehicles, electric motorcycles, and personal mobility devices.

The lithium secondary battery may include an electrode assembly wound with a separator interposed between a positive electrode and a negative electrode, and a case in which the electrode assembly is embedded. In addition, the positive electrode, the negative electrode, and the separator may be impregnated with an electrolyte.

The lithium secondary battery may have various shapes such as a prismatic shape, a cylindrical shape, and a pouch shape.

The negative electrode includes a negative electrode material including a negative electrode active material, a conductive material, and a binder; And it may include a current collector supporting the negative electrode material.

The anode active material includes a material capable of reversibly intercalating and deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and undoping lithium, and a transition metal oxide. can include

As the material capable of reversibly intercalating and deintercalating the lithium ions, crystalline carbon, amorphous carbon, or a mixture thereof may be exemplified as a carbonaceous material. Specifically, the carbonaceous material includes natural graphite, artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitches, mesophase pitch based carbon fibers, meso-carbon microbeads, petroleum or coal tar pitch derived cokes, soft carbon, hard carbon, and the like.

The alloy of lithium metal is Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, Sn, Bi, Ga, and Cd It may be an alloy of a metal selected from the group consisting of and lithium.

The material capable of doping and undoping the lithium is Si, Si—C complex, SiOx (0<x<2), Si—Q alloy (Q is an alkali metal, an alkaline earth metal, a group 13 element, a group 14 element, a group 15 It is an element selected from the group consisting of elements, group 16 elements, transition metals, rare earth elements, and combinations thereof; excluding Si), Sn, SnO ₂ , Sn-R alloy (wherein R is an alkali metal, an alkali An element selected from the group consisting of earth metals, group 13 elements, group 14 elements, group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof; except for Sn), and the like. In addition, at least one of the above examples and SiO ₂ may be mixed and used as the material capable of doping and undoping the lithium. Q and R are Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe , Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S , Se, Te, Po, etc.

The transition metal oxide may be vanadium oxide, lithium vanadium oxide, or lithium titanium oxide.

Preferably, the negative electrode may include at least one negative electrode active material selected from the group consisting of carbonaceous materials and silicon compounds.

Here, the carbonaceous material is, as previously exemplified, natural graphite, artificial graphite, kish graphite, pyrolytic carbon, mesophase pitch, mesophase pitch-based carbon fiber, carbon microspheres, petroleum or coal-based coke, softened carbon, and hardened carbon. It is one or more substances selected from the group consisting of. In addition, the silicon compound is a compound containing Si previously exemplified, that is, Si, a Si—C composite, SiOx (0<x<2), the Si—Q alloy, a mixture thereof, or at least one of these and SiO It can be a mixture of the ₂ .

According to one embodiment, the negative active material may be included in 85% to 98% by weight based on the total weight of the negative electrode material.

Specifically, the content of the negative electrode active material is 85% by weight or more, or 87% by weight or more, or 90% by weight or more based on the total weight of the negative electrode material; And, it may be 98% by weight or less, or 97% by weight or less, or 95% by weight or less.

Preferably, the content of the negative electrode active material is 85% to 97% by weight, or 87% to 97% by weight, or 87% to 95% by weight, or 90% to 95% by weight based on the total weight of the negative electrode material. can be

The conductive material, the binder, and the current collector included in the negative electrode material are replaced with the contents described in the positive electrode for a lithium secondary battery.

The separator separates the positive electrode and the negative electrode and provides a passage for lithium ions to move. As the separator, any material known to be applicable to a separator of a lithium secondary battery in the art to which the present invention pertains may be used without particular limitation. It is preferable that the separator has excellent wettability to the electrolyte while having low resistance to the movement of ions in the electrolyte.

Specifically, the separator may be a porous polymer film made of a polyolefin-based polymer such as polyethylene, polypropylene, ethylene-butene copolymer, ethylene-hexene copolymer, or ethylene-methacrylate copolymer. The separator may be a multilayer film in which the porous polymer film is stacked in two or more layers. The separator may be a non-woven fabric including glass fibers, polyethylene terephthalate fibers, and the like. In addition, the separator may be coated with a ceramic component or a polymer material to secure heat resistance or mechanical strength.

Meanwhile, as the electrolyte, any material known to be applicable to a lithium secondary battery in the art to which the present invention pertains may be used without particular limitation. For example, the electrolyte may be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, or a molten inorganic electrolyte.

Specifically, the electrolyte may include a non-aqueous organic solvent and a lithium salt.

The non-aqueous organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move.

Specifically, the non-aqueous organic solvent includes ester-based solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; etheric solvents such as dibutyl ether and tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and carbonate-based solvents such as propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (R is a C2 to C20 straight-chain, branched or cyclic hydrocarbon group, and may contain a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; and sulfolane.

Among the above examples, a carbonate-based solvent may be preferably used as the non-aqueous organic solvent.

In particular, considering the charge/discharge performance of the battery and compatibility with the sacrificial cathode material, the non-aqueous organic solvent is a cyclic carbonate (eg, ethylene carbonate, propylene carbonate) having high ion conductivity and high dielectric constant and a low point A mixture of the above linear carbonates (e.g., ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate) can be preferably used. In this case, mixing and using the cyclic carbonate and the linear carbonate at a volume ratio of 1:1 to 1:9 may be advantageous for the expression of the above-described performance.

In addition, as the non-aqueous organic solvent, a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 1:2 to 1:10; Alternatively, a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio of 1 to 3:1 to 9:1 may be preferably used.

The lithium salt contained in the electrolyte is dissolved in the non-aqueous organic solvent and acts as a source of lithium ions in the battery to enable basic operation of the lithium secondary battery and to promote the movement of lithium ions between the positive electrode and the negative electrode. play a role

Specifically, the lithium salt is LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiN(C ₂ F ₅ SO ₃ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ , LiN(CF ₃ SO ₂ ) ₂ , LiN(SO ₂ F) ₂ (LiFSI, lithium bis(fluorosulfonyl)imide), LiCl, LiI, and LiB(C ₂ O4) It can be _2nd . Preferably, the lithium salt may be LiPF ₆ , LiFSI, and mixtures thereof.

The lithium salt may be included in the electrolyte at a concentration of 0.1 M to 2.0 M. The lithium salt included in the concentration range provides excellent electrolyte performance by imparting appropriate conductivity and viscosity to the electrolyte.

Optionally, the electrolyte may contain additives for the purpose of improving lifespan characteristics of a battery, suppressing battery capacity decrease, and improving battery discharge capacity.

For example, the additive may be a haloalkylene carbonate-based compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, triamine hexaphosphate mead, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride, and the like. . The additive may be included in an amount of 0.1 wt% to 5 wt% based on the total weight of the electrolyte.

According to the present invention, there is provided a method for producing a lithium transition metal oxide for a lithium secondary battery without an additional crushing process for raw materials by suppressing the formation of cobalt oxide chunks.

Hereinafter, the operation and effect of the invention will be described in more detail through specific examples of the invention. However, this is presented as an example to aid understanding of the invention. The scope of the invention is not intended to be limited in any way through the following examples, and it will be clear to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention.

Example 1

(1) Synthesis of lithium transition metal oxide

A mixture of 85.7 g of Co ₃ O ₄ and 27.15 g of ZnO (molar ratio Co: Zn = 0.75: 0.25) was placed in a furnace, evacuated, and heat-treated for 5 hours under an Ar atmosphere and 1000 °C. The obtained Co _0.75 Zn _0.25 O particles were placed in a sieve shaker equipped with a sieve having a sieve opening of 38 μm and classified for 10 minutes. The Co _0.75 Zn _0.25 O particles passed through the sieve in a yield of 98% based on total weight.

Co _0.75 Zn _0.25 O particles and Li ₂ O passed through the sieve were mixed at a molar ratio of 1: 3 (Co+Zn: Li), put into a furnace, evacuated, and then heat-treated for 12 hours under a N ₂ atmosphere and 600 ° C. , obtained a lithium transition metal oxide, Li ₆ Co _0.75 Zn _0.25 O ₄ .

After pulverizing the lithium transition metal oxide using a jaw crusher, it was classified using the pulverizer.

(2) Manufacture of coin half cell

The lithium transition metal oxide (Li ₆ Co _0.75 Zn _0.25 O ₄ ) as a cathode active material, Li-435 (manufactured by Denka) as a conductive material, KF9700 (manufactured by Kureha) and BM-730H (manufactured by Zeon) as a binder were 95 : 3: 1.7: mixed with an organic solvent (N-methylpyrrolidone) at a weight ratio of 0.3 to prepare a cathode material slurry. The positive electrode material slurry was coated on one side of a current collector, which is an aluminum foil having a thickness of 15 μm, and rolled and dried to prepare a positive electrode.

A lithium foil having a thickness of 300 μm was used as the negative electrode. As an electrolyte, 1M LiPF ₆ dissolved in a mixed solvent having a volume ratio of ethylene carbonate (EC): dimethyl carbonate (DMC): diethyl carbonate (DEC) of 1:2:1 was used. A glass fiber sheet having a thickness of 260 nm was used as the separator. A coin half-cell was manufactured using each of the above components and according to a conventional manufacturing method.

Example 2

(1) Synthesis of lithium transition metal oxide

A mixture of 77.13 g of Co ₃ O ₄ , 26.78 g of ZnO and 1.34 g of Al ₂ O ₃ (molar ratio Co: Zn: Al = 0.73: 0.25: 0.02) was put into a furnace, and after vacuum evacuation, Ar atmosphere and Heat treatment was performed at 1000 °C for 5 hours. The obtained Co _0.73 Zn _0.25 Al _0.02 O particles were placed in a pulverizer equipped with a sieve having a sieve size of 38 μm and classified for 10 minutes. The Co _0.73 Zn _0.25 Al _0.02 O particles passed through the sieve in a yield of 98% based on the total weight.

Co _0.73 Zn _0.25 Al _0.02 O particles that have passed through the sieve and Li ₂ O are mixed at a molar ratio of ₁ :3 (Co+Zn+Al:Li), put into a furnace, and after vacuum evacuation, 12 After heat treatment for a period of time, a lithium transition metal oxide of Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ was obtained.

After pulverizing the lithium transition metal oxide using a jaw crusher, it was classified using the pulverizer.

(2) Manufacture of coin half cell

A coin half-cell was manufactured in the same manner as in Example 1, except that the lithium transition metal oxide (Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ ) obtained by the above method was used as the positive electrode active material.

Example 3

(1) Synthesis of lithium transition metal oxide

A mixture of 85.7 g Co ₃ O ₄ , 31.48 g ZnO, 3.94 g Al ₂ O ₃ , and 2 1.91 g ZrO (molar ratio Co: Zn: Al: Zr = 0.69: 0.25: 0.05: 0.01) was placed in a furnace (furnace), and after vacuum evacuation, heat treatment was performed for 10 hours under Ar atmosphere and 1000 ℃. The obtained Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O particles were placed in a pulverizer equipped with a sieve having a sieve size of 38 μm and classified for 10 minutes. The Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O particles passed through the sieve in a yield of 98% based on the total weight.

Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O particles passing through the sieve and Li ₂ O were mixed in a molar ratio of 1:3 (Co+Zn+Al+Zr:Li), put into a furnace, and after vacuum evacuation, N ₂ atmosphere and Heat treatment was performed at 600° C. for 12 hours to obtain a lithium transition metal oxide of Li ₆ Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O ₄ .

After pulverizing the lithium transition metal oxide using a jaw crusher, it was classified using the pulverizer.

(2) Manufacture of coin half cell

A coin half-cell was manufactured in the same manner as in Example 1, except that the lithium transition metal oxide (Li ₆ Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O ₄ ) obtained by the above method was used as the positive electrode active material.

Comparative Example 1

(1) Synthesis of lithium transition metal oxide

After putting 100 g of Co ₃ O ₄ in a furnace and vacuuming, heat treatment was performed for 10 hours under an Ar atmosphere and 1000 °C. Through the heat treatment, very hard CoO chunks having a particle size of several hundred micrometers were formed. After pulverizing the CoO chunks using a jaw crusher, they were placed in a sieve equipped with a sieve having a sieve size of 38 μm and classified for 10 minutes.

A raw material mixture was prepared by solid-phase mixing CoO, ZnO, and Li ₂ O passed through the sieve at a molar ratio of Co: Zn: Li = 0.75: 0.25: 3. The raw material mixture was placed in a furnace, evacuated, and heat-treated for 12 hours under a N ₂ atmosphere at 600° C. to obtain Li ₆ Co _0.75 Zn _0.25 O ₄ , a lithium transition metal oxide.

(2) Manufacture of coin half cell

A coin half-cell was manufactured in the same manner as in Example 1, except that the lithium transition metal oxide (Li ₆ Co _0.75 Zn _0.25 O ₄ ) obtained by the above method was used as the positive electrode active material.

Comparative Example 2

(1) Synthesis of lithium transition metal oxide

After putting 100 g of Co ₃ O ₄ in a furnace and vacuuming, heat treatment was performed for 10 hours under an Ar atmosphere and 1000 °C. Through the heat treatment, very hard CoO chunks having a particle size of several hundred micrometers were formed. After pulverizing the CoO chunks using a jaw crusher, they were placed in a sieve equipped with a sieve having a sieve size of 38 μm and classified for 10 minutes.

CoO, ZnO, Al 2 O ₃ , and Li ₂ O passed through the sieve were solid-phase mixed in a molar ratio of Co: Zn: Al: Li = 0.73: 0.25: 0.02: 3 to prepare a raw material mixture. The raw material mixture was placed in a furnace, evacuated, and heat-treated for 12 hours under a N ₂ atmosphere and 600° C. to obtain Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ lithium transition metal oxide.

(2) Manufacture of coin half cell

A coin half-cell was manufactured in the same manner as in Example 1, except that the lithium transition metal oxide (Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ ) obtained by the above method was used as the positive electrode active material.

reference example

(1) Synthesis of lithium transition metal oxide

A mixture of 77.13 g of Co ₃ O ₄ and 30.41 g of ZnO (molar ratio Co: Zn = 0.72: 0.28) was placed in a furnace, evacuated, and heat-treated for 5 hours under an Ar atmosphere and 1000 °C. The obtained Co _0.72 Zn _0.28 O particles were put into a pulverizer equipped with a sieve having a sieve size of 38 μm and classified for 10 minutes. The Co _0.72 Zn _0.28 O particles passed through the sieve in a yield of 90% based on total weight.

Co _0.72 Zn _0.28 O particles and Li ₂ O passed through the sieve were mixed at a molar ratio of 1: 3 (Co+Zn: Li), put into a furnace, evacuated, and heat-treated for 12 hours under a N ₂ atmosphere and 600 ° C. , obtained a lithium transition metal oxide, Li ₆ Co _0.72 Zn _0.28 O ₄ .

After pulverizing the lithium transition metal oxide using a jaw crusher, it was classified using the pulverizer.

test example

(1) Whether cobalt oxide is single phase

Using an X-ray diffraction analyzer (Model PW1830, Philips Co.), the presence or absence of a single phase was evaluated for the hetero-element doped cobalt oxide obtained in Examples and Reference Examples and the cobalt oxide chunk obtained in Comparative Example.

cobalt oxide
Whether shredding is required classification yield
(%) XRD single phase Example 1 X 98 O Example 2 X 98 O Example 3 X 98 O Comparative Example 1 O 95 O Comparative Example 2 O 95 O reference example X 90 X

Referring to Table 1, the cobalt oxide doped with a heterogeneous element according to Examples showed a high 38 μm classification yield of 98% without an additional crushing process and was confirmed to have a single phase. Cobalt oxide according to Comparative Examples (CoO) has a single phase, but forms large and hard CoO chunks, requiring an additional crushing process. The classification yield for the comparative examples is for cobalt oxide after the additional crushing process.

The cobalt oxide doped with a heterogeneous element according to the reference example showed a classification yield of 90% without an additional crushing process. However, it was confirmed that the cobalt oxide doped with a different element according to the reference example did not form a single phase and was heterogeneous because the phases of the particles passing through the 38 μm sieve and the phases of the particles not passing through the sieve were different.

(2) Formation (initial charge) capacity and charge/discharge capacity measurement

For the coin half-cells prepared in Examples and Comparative Examples, constant current-constant voltage charging up to 4.25 V at 0.1 C under 25 ° C, constant current discharging up to 2.5 V, and cycles with a break of 20 minutes between charge and discharge, formation capacity and The charge/discharge capacity was measured.

In Table 1 below, irreversible capacity may be defined as “charge capacity - discharge capacity = irreversible capacity”.

Formation capacity (mAh/g) Irreversible capacity (mAh/g) Example 1 785.2 750.9 Example 2 772.7 746.2 Example 3 778.3 750.5 Comparative Example 1 785.4 756.4 Comparative Example 2 772.5 747.0

Referring to Table 2, it was confirmed that the coin half-cell according to the embodiments can exhibit an equivalent level of formation capacity and irreversible capacity compared to the coin half-cell according to the comparative examples.

Claims (12)

heat-treating a mixture of cobalt oxide and the oxide of a different element under an inert atmosphere at a temperature of 900° C. to 1100° C. for 4 to 10 hours to obtain cobalt oxide doped with a different element; and
Obtaining lithium cobalt oxide doped with a different element by heat-treating the mixture of cobalt oxide and lithium oxide doped with the different element under an inert atmosphere and at a temperature of 500 ° C to 700 ° C for 1 hour to 15 hours
A method for producing a lithium transition metal oxide for a lithium secondary battery comprising a.
According to claim 1,
The cobalt oxide is Co ₃ O ₄ A method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
The mixture of the cobalt oxide and the heterogeneous element oxide comprises a molar ratio of 70 mol% to 80 mol% of cobalt and 20 mol% to 30 mol% of the heterogeneous element, a method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
The heterogeneous element oxide includes at least one element selected from the group consisting of a Group 2 element, a Group 13 element, a Group 14 element, a 4th period transition metal, a 5th period transition metal, and a 6th period transition metal, and a lithium transition metal for a lithium secondary battery. A method for producing metal oxides.
According to claim 4,
The Group 2 element includes at least one selected from the group consisting of Mg, Ca, Sr, and Ba,
The group 13 element includes at least one selected from the group consisting of Al, Ga and In,
The Group 14 element includes at least one selected from the group consisting of Si, Ge, and Sn,
The 4th period transition metal includes at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn,
The 5-period transition metal includes at least one selected from the group consisting of Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd,
The 6-period transition metal includes at least one selected from the group consisting of Lu, Hf, Ta, W, Re, Os, Ir, Pt, and Au,
A method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
The heterogeneous element oxide is a method for producing a lithium transition metal oxide for a lithium secondary battery comprising at least one element selected from the group consisting of Zn, Al, Mg, Ti, Zr, Nb, and W.
According to claim 1,
The cobalt oxide doped with the heterogeneous element is a particle having a particle size of 1 μm to 100 μm, a method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
95% or more of the cobalt oxide doped with the heterogeneous element is a particle having a particle size of 38 μm or less, a method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
The mixture of the cobalt oxide doped with the heterogeneous element and the lithium oxide contains a molar ratio of 2 to 4 times lithium relative to the sum of the molar numbers of cobalt and the heterogeneous element, lithium transition metal oxide for a lithium secondary battery Manufacturing method.
According to claim 1,
The lithium cobalt oxide doped with the heterogeneous element is represented by Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3 below. Method for producing a lithium transition metal oxide for a lithium secondary battery:

[Formula 1]
Li ₆ Co _1-x M ¹ _x O ₄
In Formula 1,
M ¹ is at least one element selected from the group consisting of a Group 2 element, a Group 13 element, a Group 14 element, a 4th period transition metal, a 5th period transition metal, and a 6th period transition metal;
x is from 0.05 to 0.80;

[Formula 2]
Li ₆ Co _1-xy Zn _x M ² _y O ₄
In Formula 2,
M ² is a Group 2 element, a Group 13 element, a Group 14 element, a Period 5 transition metal, or a Period 6 transition metal;
x is from 0.1 to 0.7;
y is from 0.01 to 0.1;

[Formula 3]
Li ₆ Co _1-xyz Zn _x Zr _y M ³ _z O ₄
In Formula 3,
M ³ is a Group 2 element, a Group 13 element, a Group 14 element, or a Period 6 transition metal;
x is from 0.1 to 0.7;
y is from 0.01 to 0.05;
z is from 0.01 to 0.1.
According to claim 10,
M ¹ includes at least one element selected from the group consisting of Zn, Al, Mg, Ti, Zr, Nb, and W;
M ² includes an element of Al, Mg, Ti, Zr, Nb, or W;
Wherein M ³ includes an element of Al, Mg, Nb, or W,
A method for producing a lithium transition metal oxide for a lithium secondary battery.
According to claim 1,
Li ₆ Co _0.95 Zn _0.05 O ₄ , Li ₆ Co _0.9 Zn _0.1 O ₄ , Li ₆ Co _0.85 Zn _0.15 O ₄ , Li ₆ Co _0.8 Zn _0.2 O ₄ , Li ₆ Co _0.75 Zn _0.25 O ₄ , Li ₆ Co _0.7 Zn _0.3 O ₄ , Li ₆ Co _0.65 Zn _0.35 O ₄ , Li ₆ Co _0.6 Zn _0.4 O ₄ , Li ₆ Co _0.55 Zn _0.45 O ₄ , Li ₆ Co _0.5 Zn _0.5 O ₄ , Li ₆ Co _0.45 Zn _0.55 O ₄ , Li ₆ Co _0.4 Zn _0.6 O ₄ , Li ₆ Co _0.35 Zn _0.65 O ₄ , Li ₆ Co _0.3 Zn _0.7 O ₄ , Li ₆ Co _0.25 Zn _0.75 O ₄ , Li ₆ Co _0.2 Zn _0.8 O ₄ ; Li ₆ Co _0.95 Al _0.05 O ₄ , Li ₆ Co _0.9 Al _0.1 O ₄ , Li ₆ Co _0.85 Al _0.15 O ₄ , Li ₆ Co _0.8 Al _0.2 O ₄ , Li ₆ Co _0.75 Al _0.25 O ₄ , Li ₆ Co _0.7 Al _0.3 O ₄ , Li ₆ Co _0.65 Al _0.35 O ₄ , Li ₆ Co _0.6 Al _0.4 O ₄ , Li ₆ Co _0.55 Al _0.45 O ₄ , Li ₆ Co _0.5 Al _0.5 O ₄ , Li ₆ Co _0.45 Al _0.55 O ₄ , Li ₆ Co _0.4 Al _0.6 O ₄ , Li ₆ Co _0.35 Al _0.65 O ₄ , Li ₆ Co _0.3 Al _0.7 O ₄ , Li ₆ Co _0.25 Al _0.75 O ₄ , Li ₆ Co _0.2 Al _0.8 O ₄ ; Li ₆ Co _0.95 Mg _0.05 O ₄ , Li ₆ Co _0.9 Mg _0.1 O ₄ , Li ₆ Co _0.85 Mg _0.15 O ₄ , Li ₆ Co _0.8 Mg _0.2 O ₄ , Li ₆ Co _0.75 Mg _0.25 O ₄ , Li ₆ Co _0.7 Mg _0.3 O ₄ , Li ₆ Co _0.65 Mg _0.35 O ₄ , Li ₆ Co _0.6 Mg _0.4 O ₄ , Li ₆ Co _0.55 Mg _0.45 O ₄ , Li ₆ Co _0.5 Mg _0.5 O ₄ , Li ₆ Co _0.45 Mg _0.55 O ₄ , Li ₆ Co _0.4 Mg _0.6 O ₄ , Li ₆ Co _0.35 Mg _0.65 O ₄ , Li ₆ Co _0.3 Mg _0.7 O ₄ , Li ₆ Co _0.25 Mg _0.75 O ₄ , Li ₆ Co _0.2 Mg _0.8 O ₄ ; Li ₆ Co _0.95 Ti _0.05 O ₄ , Li ₆ Co _0.9 Ti _0.1 O ₄ , Li ₆ Co _0.85 Ti _0.15 O ₄ , Li ₆ Co _0.8 Ti _0.2 O ₄ , Li ₆ Co _0.75 Ti _0.25 O ₄ , Li ₆ Co _0.7 Ti _0.3 O ₄ , Li ₆ Co _0.65 Ti _0.35 O ₄ , Li ₆ Co _0.6 Ti _0.4 O ₄ , Li ₆ Co _0.55 Ti _0.45 O ₄ , Li ₆ Co _0.5 Ti _0.5 O ₄ , Li ₆ Co _0.45 Ti _0.55 O ₄ , Li ₆ Co _0.4 Ti _0.6 O ₄ , Li ₆ Co _0.35 Ti _0.65 O ₄ , Li ₆ Co _0.3 Ti _0.7 O ₄ , Li ₆ Co _0.25 Ti _0.75 O ₄ , Li ₆ Co _0.2 Ti _0.8 O ₄ ; Li ₆ Co _0.95 Zr _0.05 O ₄ , Li ₆ Co _0.9 Zr _0.1 O ₄ , Li ₆ Co _0.85 Zr _0.15 O ₄ , Li ₆ Co _0.8 Zr _0.2 O ₄ , Li ₆ Co _0.75 Zr _0.25 O ₄ , Li ₆ Co _0.7 Zr _0.3 O ₄ , Li ₆ Co _0.65 Zr _0.35 O ₄ , Li ₆ Co _0.6 Zr _0.4 O ₄ , Li ₆ Co _0.55 Zr _0.45 O ₄ , Li ₆ Co _0.5 Zr _0.5 O ₄ , Li ₆ Co _0.45 Zr _0.55 O ₄ , Li ₆ Co _0.4 Zr _0.6 O ₄ , Li ₆ Co _0.35 Zr _0.65 O ₄ , Li ₆ Co _0.3 Zr _0.7 O ₄ , Li ₆ Co _0.25 Zr _0.75 O ₄ , Li ₆ Co _0.2 Zr _0.8 O ₄ ; Li ₆ Co _0.95 Nb _0.05 O ₄ , Li ₆ Co _0.9 Nb _0.1 O ₄ , Li ₆ Co _0.85 Nb _0.15 O ₄ , Li ₆ Co _0.8 Nb _0.2 O ₄ , Li ₆ Co _0.75 Nb _0.25 O ₄ , Li ₆ Co _0.7 Nb _0.3 O ₄ , Li ₆ Co _0.65 Nb _0.35 O ₄ , Li ₆ Co _0.6 Nb _0.4 O ₄ , Li ₆ Co _0.55 Nb _0.45 O ₄ , Li ₆ Co _0.5 Nb _0.5 O ₄ , Li ₆ Co _0.45 Nb _0.55 O ₄ , Li ₆ Co _0.4 Nb _0.6 O ₄ , Li ₆ Co _0.35 Nb _0.65 O ₄ , Li ₆ Co _0.3 Nb _0.7 O ₄ , Li ₆ Co _0.25 Nb _0.75 O ₄ , Li ₆ Co _0.2 Nb _0.8 O ₄ ; Li ₆ Co _0.95 W _0.05 O ₄ , Li ₆ Co _0.9 W _0.1 O ₄ , Li ₆ Co _0.85 W _0.15 O ₄ , Li ₆ Co _0.8 W _0.2 O ₄ , Li ₆ Co _0.75 W _0.25 O ₄ , Li ₆ Co _0.7 W _0.3 O ₄ , Li ₆ Co _0.65 W _0.35 O ₄ , Li ₆ Co _0.6 W _0.4 O ₄ , Li ₆ Co _0.55 W _0.45 O ₄ , Li ₆ Co _0.5 W _0.5 O ₄ , Li ₆ Co _0.45 W _0.55 O ₄ , Li ₆ Co _0.4 W _0.6 O ₄ , Li ₆ Co _0.35 W _0.65 O ₄ , Li ₆ Co _0.3 W _0.7 O ₄ , Li ₆ Co _0.25 W _0.75 O ₄ , Li ₆ Co _0.2 W _0.8 O ₄ , Li ₆ Co _0.77 Zn _0.2 Al _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Al _0.04 O ₄ , Li ₆ Co _0.73 Zn _0.25 Al _0.02 O ₄ , Li ₆ Co _0.75 Zn _0.2 Al _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Al _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Al _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Al _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Mg _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Mg _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Mg _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Mg _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Mg _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Mg _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Ti _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Ti _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Ti _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Ti _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 T i _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Ti _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Zr _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Zr _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Zr _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Zr _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Zr _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Zr _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 Nb _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 Nb _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 Nb _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 Nb _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 Nb _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 Nb _0.05 O ₄ , Li ₆ Co _0.77 Zn _0.2 W _0.03 O ₄ , Li ₆ Co _0.76 Zn _0.2 W _0.04 O ₄ , Li ₆ Co _0.75 Zn _0.2 W _0.05 O ₄ , Li ₆ Co _0.67 Zn _0.3 W _0.03 O ₄ , Li ₆ Co _0.66 Zn _0.3 W _0.04 O ₄ , Li ₆ Co _0.65 Zn _0.3 W _0.05 O ₄ , Li ₆ Co _0.69 Zn _0.25 Al _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Mg _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Nb _{0.05 Zr} O ₄ , Li ₆ Co _0.69 Zn _0.25 W _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.69 Zn _0.25 Al _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _0.25 Mg _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _{0.25 Nb} Zr _0.03 O ₄ , Li ₆ Co _0.69 Zn _0.25 W _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Al _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 Mg _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 Nb _0.05 Zr _0.01 O ₄ , Li ₆ Co _0.64 Zn _0.3 W _0.05 Zr _{4 0.01} Li ₆ Co _0.64 Zn _0.3 Al _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Mg _0.03 Zr _0.03 O ₄ , Li ₆ Co _0.64 Zn _0.3 Nb _0.03 Zr _0.03 O ₄ , or Li ₆ Co _0.64 Zn _0.3 W _{0.03 Zr} O ₄ Phosphorus, a method for producing a lithium transition metal oxide for a lithium secondary battery.