KR20220039060A - Active material and the method of manufacturing this - Google Patents

Abstract

The present invention can provide an electrode active material capable of realizing a battery with high capacity, excellent capacity retention (life characteristics) according to charging and discharging, and excellent conductivity, and a method for manufacturing the same.

Description

Active material and the method of manufacturing this

It relates to an electrode active material and a method for manufacturing the same.

Lithium-ion batteries are rechargeable, easy to carry, and have high output, so they are widely used as high-efficiency energy storage and supply devices for driving electric vehicles, portable electronic devices, and micro home appliances.

At present, when the development of electronic devices is progressing rapidly, the development of a lithium secondary battery with high energy density and output efficiency that can smoothly implement a new system and low loss in repeated charging/discharging is essential, and to achieve this, it is essential. Continuous efforts are being made to

For example, lithium-containing cobalt oxides such as LiCoO ₂ exhibiting excellent cycle characteristics, lithium-containing manganese oxides such as LiMnO ₂ and LiMn ₂ O ₄ exhibiting environmentally friendly and inexpensive properties, and lithium such as LiNiO ₂ having high capacity characteristics Research on ternary nickel-cobalt-manganese (LCM)-based positive electrode active materials, which may have the advantages of nickel oxide-containing nickel oxide, is active. At this time, when a positive electrode active material containing a high nickel content among ternary nickel-cobalt-manganese (LCM)-based positive active materials is used, a high-capacity battery can be realized at low cost, and the need for introduction thereof is increasing.

However, in the case of a ternary nickel-cobalt-manganese (LCM)-based positive electrode active material containing nickel in a high content, the structure of the positive electrode active material becomes unstable during intercalation/deintercalation of lithium ions. There are problems in that metals are eluted from the anode, etc. and deteriorated, and side reactions occur a lot due to the potential difference at the boundary where the surface of the electrode and the electrolyte come into contact when the battery is driven.

One object of the present invention is to provide an electrode active material capable of realizing a battery having high capacity and suppressing side reactions with an electrolyte, etc., and thus having excellent capacity retention (lifetime characteristics) according to charging and discharging, and excellent conductivity, and a method for manufacturing the same. .

Among the physical properties mentioned in the present specification, when the measurement temperature affects the physical properties, unless otherwise specified, the physical properties are those measured at room temperature.

As used herein, the term room temperature is a temperature in a state in which it is not particularly heated or reduced, and any one temperature within the range of about 10°C to 30°C, for example, about 15°C or more, 18°C or more, 20°C or more, or about 23 It may mean a temperature of about 27° C. or lower while being at least ℃. In addition, unless otherwise specified, the unit of temperature referred to in the present specification is °C.

The present invention may relate to an electrode active material.

The electrode active material of the present application may include, for example, an active material core, a metal oxide layer formed on the active material core, and a conductive layer formed on the metal oxide layer. In the present application, the ratio (H ₁ /H ₂ ) of the height (H ₁ ) of the metal oxide layer from the surface of the active material core and the height (H ₂ ) of the conductive layer from the surface of the metal oxide layer is, for example, It can be in the range of about 0.01 to 10.

In the present specification, "the height of A from the surface of B" is, for example, a straight line forming an angle of approximately 70° to 110° with respect to the tangent after an imaginary tangent is drawn to an arbitrary point on the surface of B. When this arbitrary point is passed through, it may mean a distance from an arbitrary point on the surface B to an intersection point between the straight line and the surface of A. In this specification, "the height of A from the surface of B" may also mean including, for example, a value obtained by arithmetic mean after measuring the above distance for n arbitrary points, where n A value of may mean an integer of 1 or more.

In the present application, in one example, the height may be measured directly or indirectly using a scanning electron microscope or a transmission electron microscope, or the like. The indirect method may be, for example, a method applicable to a layer formed by an atomic layer deposition method. The indirect method, in one example, repeats the atomic layer deposition unit process to be described below on a flat substrate such as a silicon wafer 100 times, and then measures the height of the layer deposited on the substrate with a scanning electron microscope or an ellipsometer ( Ellipsometer), and then dividing the height by 100 times, which is the number of unit processes, calculates the height of a layer formed per unit process, and then calculates the number of times the atomic layer deposition unit process described later is repeatedly performed. It may be a method of deriving by multiplying the height of the layer to be formed. The indirect method, in another example, repeats the atomic layer deposition unit process on the active material core a sufficient number of times, then measures the height of the atomic layer deposition layer formed on the active material core, and/or for atomic layer deposition It may be to conduct elemental content analysis on the particles including the layer formed by Then, the content of the metal element contained in the layer formed by the atomic layer deposition is calculated by dividing it by the number of times the unit process is performed to calculate the content of the metal element contained in the layer formed by the atomic layer deposition per unit process, Measure the content of the metal element contained in the particles, divide by the content of the metal element contained in the layer formed by atomic layer deposition per unit process, and then determine the height of the layer formed by atomic layer deposition per unit process It may be a method of deriving by multiplying.

In particular, the present inventors suppress the side reaction between the electrolyte and the electrode active material by controlling the ratio (H ₁ /H ₂ ) in the same range as described above, while also preventing the conductivity from being lowered, so that the capacity retention rate (lifetime characteristics) according to charging and discharging is It was confirmed that it is possible to provide an electrode active material capable of implementing a battery having excellent conductivity and the like. The ratio (H ₁ /H ₂ ) of the height from the surface of the active material core of the metal oxide layer (H ₁ ) and the height from the surface of the metal oxide layer of the conductive layer (H ₂ ) is 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.1 or more, 0.11 or more, 0.12 or more, 0.13 or more, or 0.14 or more, or 9.5 or less, 9 or less, 8.5 or less, 8 or less, 7.5 or less, 7 or less , 6.5 or less, 6 or less, 5.5 or less, 5 or less, 4.5 or less, 4 or less, 3.5 or less, 3 or less, 2.5 or less, 2 or less, 1.5 or less, 1 or less, or 0.5 or less.

In the present application, the metal oxide layer may have a coverage of, for example, about 80% or more on the surface of the active material core. In the present specification, the coverage of the metal oxide layer on the surface of the active material core is, for example, the ratio (D1/) of the area (D1) of the portion where the metal oxide layer is formed on the surface of the active material core to the surface area (C) of the active material core C) can mean In the present specification, the formation of the metal oxide layer may mean, for example, that the metal oxide layer is formed to a thickness sufficient to prevent the active material core from causing a side reaction with the electrolyte. In one example, the formation of the metal oxide layer may mean, for example, when the thickness of the metal oxide layer with respect to the surface of the active material core is about 0.2 nm or more. That is, in the present specification, the coverage of the metal oxide layer on the surface of the active material core is, for example, the area (D1) of the portion where the metal oxide layer is formed to be approximately 0.2 nm or more on the surface of the active material core with respect to the surface area (C) of the active material core. ) may mean a ratio (D1/C). In one example, the metal oxide layer may be formed on the surface of the active material core by repeatedly performing unit processes by an atomic layer deposition method to be described later, and the layer formed by each unit process may be formed at a sub-nanometer level. Defects may be included, but such defects may not act as significant defects with respect to the function of the metal oxide layer formed by repeatedly performing each unit process. In another example, the coverage is about 81% or more, about 82% or more, about 83% or more, about 84% or more, about 85% or more, about 86% or more, about 87% or more, about 88% or more, about 90% or more. or more, about 91% or more, about 92% or more, about 93% or more, about 94% or more, about 95% or more, about 96% or more, about 97% or more, about 98% or more, or about 99% or more. The metal oxide layer may serve to protect the active material core so that a side reaction between the active material core and the electrolyte does not occur, and the coverage is larger in terms of preventing contact between the active material core and the electrolyte from occurring, in other words, The upper limit is not particularly limited because the metal oxide layer may be more uniformly formed on the surface of the active material core, but in one example, about 100% or less, about 99% or less, about 98% or less, about 97% or less, about 96% or less, about 95% or less, about 94% or less, about 93% or less, about 92% or less, about 91% or less, about 90% or less, about 89% or less, about 88% or less, about 87% or less, or about 86% or less It may be the following, but is not limited thereto.

In the present application, the height (H ₁ ) of the metal oxide layer from the surface of the active material core may be, for example, in the range of 0.2 nm to 5 nm. By controlling the height (H ₁ ) in the same range as above, the occurrence of a phenomenon in which conductivity is inhibited due to an increase in resistance while appropriately performing the role of a protective layer to be excellent in capacity retention (life characteristics) according to charging and discharging can be prevented The height (H ₁ ) is, in another example, 0.3 nm or more, 0.4 nm or more, 0.5 nm or more, 0.6 nm or more, 0.7 nm or more, 0.8 nm or more, 0.9 nm or more, 1 nm or more, 1.1 nm or more, 1.2 nm or more , 1.3 nm or more, or 1.4 nm or more, or 4.5 nm or less, 4 nm or less, 3.5 nm or less, 3 nm or less, 2.5 nm or less, 2 nm or less, 1.9 nm or less, 1.8 nm or less, 1.7 nm or less, or 1.6 nm or less However, the present invention is not limited thereto.

The electrode active material of the present application may also include a conductive layer. The conductive layer may be formed on, for example, the metal oxide layer described above. Here, the height H ₂ from the surface of the metal oxide layer of the conductive layer may be, for example, in the range of approximately 0.5 nm to 20 nm. By controlling the height (H ₂ ) in the same range as described above, it is possible to solve the problem of reducing the specific capacity of the battery while appropriately performing the role of controlling the increase in resistance.

The term specific capacity means the capacity of the battery relative to the volume of the battery. The capacity of the battery may refer to a theoretical capacity or an actual capacity. The theoretical capacity (C _T ) is determined by the amount of the battery active material, and may be calculated according to Equation 1 below.

[Formula 1]

C _T = x × F

In Equation 1, F may mean a Faraday constant, and x may mean the number of moles of electrons generated from the reaction while the battery is completely discharged.

The actual capacity (C _p ) is, for example, due to problems such as a problem that the reactant does not participate 100% in the discharge reaction, iR drop that appears as the charge/discharge rate increases, compared to the theoretical capacity can be small

That is, in the present application, appropriately controlling the height (H ₂ ) of the conductive layer from the surface of the metal oxide layer may be important in terms of achieving a desired effect. The height (H ₂ ) is, in another example, 1 nm or more, 1.5 nm or more, 2 nm or more, 2.5 nm or more, 3 nm or more, 3.5 nm or more, 4 nm or more, 4.5 nm or more, 5 nm or more, 5.5 nm or more , 6 nm or more, 6.5 nm or more, 7 nm or more, 7.5 nm or more, 8 nm or more, 8.5 nm or more, 9 nm or more, or 9.5 nm or more, or 19.5 nm or less, 19 nm or less, 18.5 nm or less, 18 nm or less, 17.5 nm or less, 17 nm or less, 16.5 nm or less, 16 nm or less, 15.5 nm or less, 15 nm or less, 14.5 nm or less, 14 nm or less, 13.5 nm or less, 13 nm or less, 12.5 nm or less, 12 nm or less, 11.5 nm or less or less, 11 nm or less, or 10.5 nm or less.

In the present application, the coverage of the conductive layer on the surface of the metal oxide layer may be, for example, 50% or more. In the present specification, the coverage of the conductive layer on the surface of the metal oxide layer is, for example, the ratio (E) of the area (E) of the portion where the conductive layer is formed on the surface of the metal oxide layer to the surface area (D2) of the metal oxide layer (E) /D2). In the present specification, the conductive layer is formed, for example, may mean that the conductive layer is formed to a thickness such that the active material core exhibits desired conductivity without being disturbed by a metal oxide layer or the like. In one example, the formation of the conductive layer may mean, for example, when the thickness of the conductive layer with respect to the surface of the metal oxide layer is about 0.5 nm or more. That is, in this specification, the coverage of the conductive layer to the metal oxide layer is, for example, the area (D2) of the portion where the conductive layer is formed to be about 0.5 nm or more on the surface of the metal oxide layer with respect to the surface area (D2) of the metal oxide layer. ) may mean a ratio (D2/E). In another example, the coverage is about 55% or more, about 60% or more, about 65% or more, about 70% or more, about 75% or more, about 80% or more, about 85% or more, about 90% or more, or about 95% or more. may be more than The coverage of the conductive layer may be measured by quantifying it using an image analysis tool, for example, using an electron microscope.

In the electrode active material of the present application, by introducing a metal oxide layer and a conductive layer having the same height and/or coverage as described above, the side reaction between the active material core and the electrolyte is controlled while having a high capacity by combining with the active material core, which will be described later, in particular. It is possible to provide an electrode active material, etc. that enables the realization of a battery having excellent capacity retention according to charging/discharging and excellent conductivity.

The electrode active material of the present application may include, for example, lithium nickel-manganese-cobalt oxide represented by the following Chemical Formula 1, and an active material core in the form of secondary particles.

[Formula 1]

Li _x M _y O ₂

In the above formula, M may be represented by Ni _1-ab Mn _a Co _b , wherein a may be in the range of 0.02 to 0.3, b may be in the range of 0.02 to 0.3, and 1-ab may be in the range of 0.6 to 0.95. can be in the range, x can be in the range of 0.5 to 1.5, and y can be 2-x.

The active material core, which includes lithium nickel-manganese-cobalt oxide represented by Formula 1 and is in the form of secondary particles, may include Li in a molar content corresponding to x. The molar content in Formula 1 of the present specification is a value relatively determined in the relationship between Li, M and/or O, or in another example, in the relationship between Ni, Mn, and/or Co included in M in Formula 1, the molar content is relatively It may mean a fixed value. In another example, x in Formula 1 is 0.55 or more, 0.60 or more, 0.65 or more, 0.70 or more, 0.75 or more, 0.80 or more, 0.85 or more, 0.90 or more, or 0.95 or more, or 1.45 or less, 1.40 or less, 1.35 or less, 1.30 or less, 1.25 or less , 1.20 or less, 1.15 or less, 1.10 or less, or 1.05 or less, but is not limited thereto. When Li is included in the molar content within the above range, the output and/or capacity characteristics of the battery may be excellent.

M in Formula 1 may include Ni in a molar content corresponding to 1-a-b. In the present specification, the molar content of Ni in M in Formula 1 may be a value relatively determined in relation to other Mn and/or Co that may be included in M that may be included in M. In another example, 0.61 or more, 0.62 or more, 0.63 or more, 0.64 or more, 0.65 or more, 0.66 or more, 0.67 or more, 0.68 or more, 0.69 or more, 0.7 or more, 0.71 or more, 0.72 or more, 0.73 or more, 0.74 or more, 0.75 or more, 0.76 or more or more, 0.77 or more, 0.78 or more, or 0.79 or more, or 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, 0.90 or less, 0.89 or less, 0.88 or less, 0.87 or less, 0.86 or less, 0.85 or less, 0.84 or less, 0.83 or less, 0.82 or less, or It may be included in a molar content of 0.81 or less, thereby realizing a high-capacity lithium secondary battery.

M in Formula 1 may include Mn in a molar content corresponding to a. In the present specification, the molar content of Mn in M in Formula 1 may be a value relatively determined in relation to other Ni and/or Co that may be included in M. In another example, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more, or may be included in a molar content of 0.25 or less, 0.2 or less, or 0.15 or less, which is preferable in terms of stability of the electrode active material can do.

M in Formula 1 may include Co in a molar content corresponding to b. In the present specification, the molar content of Co in M in Formula 1 may be a value relatively determined in relation to other Ni and/or Mn that may be included in M. In another example, it may be included in an amount of 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more, or 0.25 or less, 0.2 or less, or 0.15 or less, which may be preferable in terms of cost.

The present application relates to an active material core in the form of secondary particles of lithium nickel-manganese-cobalt oxide represented by Chemical Formula 1 as described above in terms of realizing a high-capacity battery at low cost while exhibiting thermal stability and stable electrochemical properties. electrode active material can be used.

The secondary particles of lithium nickel-manganese-cobalt oxide represented by Chemical Formula 1 in the present application may be prepared through a technique known in the art. In one example, the secondary particles are prepared by mixing an electrode active material precursor and a lithium raw material source, and performing primary calcination in an oxidizing atmosphere to form primary particles and/or secondary main firing of the primary particles. It can be prepared including. The electrode active material precursor may be, for example, a compound including nickel (Ni), cobalt (Co), and/or manganese (Mn). The electrode active material precursor may be prepared by co-precipitation reaction by adding an ammonium cation-containing complex former and a basic compound to a transition metal solution including a nickel-containing raw material, a cobalt-containing raw material and/or a manganese-containing raw material.

The primary firing may be performed under an oxidizing atmosphere, where the oxidizing atmosphere may mean performing firing while supplying oxygen. The firing may be performed while controlling an appropriate temperature, time, and oxygen supply amount in consideration of the uniformity or crystallinity of the electrode active material. Subsequently, after forming a plastic product through the primary firing, the secondary main firing may be performed, and the firing temperature or firing time of the secondary main firing may also determine the uniformity or crystallinity of the electrode active material. It can be appropriately controlled taking into account.

The present application introduces an active material core containing a characteristic lithium nickel-manganese-cobalt oxide as described above, and includes a metal oxide and/or a conductive layer at the same height as above, so that the battery has a high capacity while charging/discharging. It is possible to provide an electrode active material capable of implementing a battery having excellent capacity retention (lifetime characteristics) as well as excellent conductivity.

The metal oxide layer of the present application includes, for example, at least one selected from the group consisting of AlO _x , ZrO _x , NbO _x , WO _x , lithium aluminum oxide, lithium zirconium oxide, lithium niobium oxide and / or lithium tungsten oxide and x may be, for example, 0 or more and 3 or less. In another example, x is 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.1 or more, 1.2 or more, 1.3 or more, or 1.4 or more, or 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, 2.5 or less, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, or 1.6 or less. In terms of preventing an increase in resistance and/or improving the effect of preventing side reactions of the electrolyte, the metal oxide layer may preferably include AlO _x (1.3≤x≤1.6).

The present inventors can more effectively implement a battery having the desired performance and/or stability by controlling the nickel (Ni) content of the active material core having the above-described characteristics and the metal content ratio of the above-described metal oxide layer to a predetermined range. It was confirmed that it is possible to provide an electrode active material and the like.

The present application may relate to an electrode active material having a molar content ratio of nickel (Ni) in the active material core to metal in the metal oxide layer in a range of, for example, 50 ppm to 10000 ppm. In another example, the content ratio of the metal of the metal oxide layer to the nickel (Ni) content of the active material core is 55 ppm or more, 60 ppm or more, 65 ppm or more, 70 ppm or more, 75 ppm or more, 80 ppm or more, 85 ppm or more, 90 ppm or more, or 95 ppm or more, or 9500 ppm or less, 9000 ppm or less, 8500 ppm or less, 8000 ppm or less, 7500 ppm or less, 7000 ppm or less, or 6500 ppm or less. ~

The conductive layer of the present application may include, for example, any one or a combination of two or more selected from the group consisting of a carbon material, a metal, a conductive oxide, and/or a conductive polymer. In view of the conductivity of the electrode active material, the conductive layer of the present application may preferably include, for example, amorphous or crystalline carbon including amorphous or partially crystalline carbon.

The present application can implement a battery with high capacity and excellent capacity retention (lifetime characteristics) and conductivity according to charging and discharging while appropriately controlling the material, height, etc. of the active material core, metal oxide layer and/or conductive layer as described above. It is possible to provide an electrode active material and the like.

The present application may also relate to, for example, a method of manufacturing an electrode active material.

The present application relates to an electrode active material comprising a first step of forming a metal oxide layer on an active material core through an atomic layer deposition (ALD) method or a molecular layer deposition (MLD) method It may be about the method.

When the metal oxide layer is formed by the ALD or MLD, the metal oxide layer may be formed thinly and uniformly. The uniform formation of the metal oxide layer in the present specification means, for example, for any active material core, uniformity between the heights of the metal oxide layer from the surface of the any active material core (the height of the metal oxide layer in the active material) uniformity) or the uniformity between the heights of the metal oxide layer from the surface of each active material core (height uniformity of the metal oxide layer between the active materials), preferably, the height uniformity of the metal oxide layer in the active material And it may mean a state in which all of the height uniformity of the metal oxide layer between the active materials is satisfied.

In the present application, the term ALD (or MLD) refers to a self-limiting surface treatment method in which thin film layers are formed one by one with an atomic (or molecular) thickness. In the present application, the self-limiting surface treatment method may mean that the atomic layer (or molecular layer) is laminated in only one layer per unit process (Cycle) even if a large amount of a source such as a metal precursor is supplied. .

The ALD (or MLD) method is a reaction in which one reactant causes a chemical reaction with the substrate surface to cause chemical adsorption, and then a second or third reactant is injected to form a thin film as chemical adsorption occurs again on the substrate can be That is, as a method of forming a thin film through chemisorption through periodic supply of each reactant, the reaction occurs only on the surface of the reactant and the target material, for example, the active material core, and the reaction between the reactant and the reactant does not occur, so the atoms (or Molecular) unit deposition may be possible. In the case of the ALD (or MLD) method, for example, a metal oxide layer may be easily formed at a low temperature. In the present application, the ALD (or MLD) may be performed within a temperature range of, for example, 60°C to 300°C. In another example, the temperature is 70 ℃ or more, 80 ℃ or more, 90 ℃ or more, 100 ℃ or more, 110 ℃ or more, 120 ℃ or more, 130 ℃ or more, 140 ℃ or more, 150 ℃ or more, 160 ℃ or more, 170 ℃ or more. , 180 ° C or higher or 190 ° C or higher or 290 ° C or lower, 280 ° C or lower, 270 ° C or lower, 260 ° C or lower, 250 ° C or lower, 240 ° C or lower, 230 ° C or lower, 220 ° C or lower or 210 ° C or lower. there is. The ALD (or MLD) of the present application may be performed in the temperature range as described above, so that the reaction may be smoothly performed and/or the metal oxide layer may be uniformly formed.

In the present application, the ALD (or MLD) includes, for example, injecting a metal precursor into a chamber in which an active material core is located, purging the chamber, injecting an oxidizing agent into the chamber, and/or purging the chamber It may include a unit process comprising the steps of:

As the chamber capable of performing the ALD (or MLD), an ALD (or MLD) chamber commonly used in the technical field of the present invention may be used.

In the present application, the metal precursor is, for example, at least one selected from the group consisting of aluminum (Al), zirconium (Zr), niobium (Ni), tungsten (W) and/or lithium (Li), preferably aluminum At least one selected from the group consisting of (Al), zirconium (Zr) and/or niobium (Ni), and more preferably aluminum (Al), when the metal precursor includes the above-mentioned metal atom , it may be more preferable in terms of stabilizing the lattice structure of the active material core and/or preventing side reactions between the electrolyte and the active material core.

When the metal precursor includes aluminum (Al), the metal precursor is, for example, trimethyl aluminum, triethyl aluminum, aluminum ethoxide, and tris (diethylami). Also) aluminum (Tris (diethylamido) aluminum) may include at least one selected from the group consisting of, preferably trimethyl aluminum (Trimethyl Aluminum).

The metal oxide layer may be formed through the reaction of Scheme 1 below by an ALD method using, for example, trimethyl aluminum as a metal precursor.

[Scheme 1]

2Al(CH ₃ ) ₃ +3H ₂ O → Al ₂ O ₃ + 6CH ₄

In the present application, the purge gas used in the purging of the chamfer may be, for example, at least one selected from the group consisting of Ar, N ₂ and an inert gas, preferably Ar or N ₂ .

In the present application, the oxidizing agent may be, for example, water vapor (H ₂ O), ozone (O ₃ ) and/or oxygen plasma, by purging the chamfer performed after the step of injecting the oxidizing agent, Impurities and unreacted components in the chamber may be removed.

By performing the unit process of the above steps, the above-described metal oxide layer, for example, AlO _x , ZrO _x , NbO _x , WO _x , lithium aluminum oxide, lithium zirconium oxide, lithium niobium oxide and/or lithium tungsten A metal oxide layer including at least one selected from the group consisting of oxides may be formed.

In the present application, the metal oxide layer may be formed by, for example, repeating the unit process of ALD (or MLD) about 1 to 20 times. When the ALD (or MLD) of the present application is performed by repeating the unit process for the same number of times as described above, it may be desirable to prevent an increase in resistance due to an excessively thick metal oxide layer and also effectively prevent side reactions with an electrolyte. . In another example, the metal oxide layer of the present application may perform the unit process of the ALD (or MLD) approximately 2 or more times, 3 or more times, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, or 9 or more, or 19 or less, 18 or less, 17 or less, 16 or less, 15 or less, 14 or less, 13 or less, 12 or less, or 11 or less. By performing ALD (or MLD) at the same number of times as described above, a metal oxide layer having the above-described height and the like may be formed.

According to the present application, by forming the metal oxide layer by the ALD and/or MLD method as described above, the capacity retention rate is excellent, and the resistance increase rate is also appropriately controlled by effectively suppressing side reactions between the active material core and the electrolyte. It is possible to provide a method for manufacturing an electrode active material with

The method for manufacturing an electrode active material of the present application may include, for example, a second step of forming a conductive layer on the metal oxide layer through chemical vapor deposition (CVD). In the CVD, a reaction gas is injected to cause a reaction such as chemical bonding through energy, for example, heat and/or plasma, and the resulting product is stacked on the surface of a target material, for example, a metal oxide layer to form a thin layer. It may mean to form a film. Plasma Enhanced Chemical Vapor Deposition (PECVD), Atmosphere Pressure Chemical Vapor Deposition (APCVD), Low Pressure Chemical Vapor Deposition (LPCVD), and/or HDPCVD (High Density Plasma Chemical Vapor Plasma) and the like can be appropriately selected.

CVD of the present application may be performed in a known manner. In one example, CVD includes purging by injecting an inert gas into a chamber in which the active material core on which the metal oxide layer is formed is located, heating the chamber to a reaction temperature, injecting a reaction gas, and/or cooling the chamber and the like, but is not limited thereto, and may be performed in a known manner.

As the chamber capable of performing the CVD, a CVD chamber commonly used in the technical field of the present invention may be used.

In the present application, the inert gas used in the purging of the chamfer may be, for example, at least one selected from the group consisting of Ar, N ₂ and/or air, preferably Ar or N ₂ .

In the present application, in the step of heating the chamber to the reaction temperature, the reaction temperature may be, for example, in the range of 400°C to 600°C, in another example, 410°C or more, 420°C or more, 430°C or more, 440 ℃ or higher, 450 °C or higher, 460 °C or higher, 470 °C or higher, 480 °C or higher, 490 °C or higher, or 590 °C or lower, 580 °C or lower, 570 °C or lower, 560 °C or lower, 550 °C or lower, 540 °C or lower, 530 °C or lower , 520 ℃ or less or 510 ℃ or less, but is not limited thereto.

In the present application, the step of injecting the reaction gas may be, for example, directly injecting acetylene, ethylene, methane or ethanol in the form of a gas or injecting by bubbling with an inert gas, but is not limited thereto, and conduction In terms of forming the layer more uniformly, it may be preferable to inject hydrogen together. Here, for example, hydrogen may be introduced at a flow rate of about 1% to 200% compared to the reaction gas. In another example, the hydrogen is approximately 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 190% or more compared to the reaction gas. Below, 180% or less, 170% or less, 160% or less, 150% or less, 140% or less, 130% or less, 120% or less, or 110% or less can be input at a flow rate ratio. In terms of effectively proceeding the reaction even at a low temperature, the reaction gas may preferably be acetylene, but is not limited thereto.

In the present application, the vacuum chamber may be controlled to be, for example, within a pressure range of 1 Torr to 30 Torr. The step of cooling in the vacuum chamber, for example, may refer to the step of reducing the temperature of the vacuum chamber to be within 10 ℃ to 100 ℃, in another example, 90 ℃ or less, 80 ℃ or less, 70 ℃ or less, 60 ℃ or less, 50 °C or less, 40 °C or less, or 30 °C or less, or 11 °C or more, 12 °C or more, 13 °C or more, 14 °C or more, 15 °C or more, 16 °C or more, 17 °C or more, 18 °C or more, 19 °C or more, or It may be 20°C or higher.

By performing the process having the steps described above, the conductive layer can be appropriately formed to have a desired height and the like.

The present application may also relate to, for example, an electrode active material slurry including an electrode active material. The composition, material, etc. of the electrode active material included in the electrode active material slurry may be identically applied to the above-described electrode active material, and the method for preparing the electrode active material is also the same as the above-described method for preparing the electrode active material. can

In the present application, the electrode active material slurry may further include a conductive material, a binder, and/or a solvent if necessary.

The conductive material is used to impart conductivity to the electrode, and when applied to a lithium secondary battery, etc., it can be used without particular limitation as long as it does not cause a chemical change in the electrode active material and has electronic conductivity. In the present application, the conductive material is, for example, graphite such as natural graphite or artificial graphite; carbon-based substances such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; 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; Alternatively, it may be a conductive polymer such as a polyphenylene derivative, and one or a mixture of two or more thereof may be used.

The conductive material may be included, for example, in an amount of about 5 parts by weight or less based on 100 parts by weight of the electrode active material. In the present application, by including the conductive material in the same weight part as described above, it is possible to provide sufficient conductivity to the electrode active material while having an excellent capacity, thereby effectively suppressing an increase in battery resistance. In another example, the conductive material is about 0.05 parts by weight or more, 0.1 parts by weight or more, 0.2 parts by weight or more, about 0.3 parts by weight or more, about 0.4 parts by weight or more, about 0.5 parts by weight or more, about 100 parts by weight of the electrode active material. 0.6 parts by weight or more, about 0.7 parts by weight or more, about 0.8 parts by weight or more, about 0.9 parts by weight or more, or about 1 parts by weight or more, or about 4.5 parts by weight or less, about 4 parts by weight or less, about 3.5 parts by weight or less, about 3 parts by weight It may be included in parts by weight or less, by about 2.5 parts by weight or less, by about 2 parts by weight or less, or by about 1.5 parts by weight or less.

The binder may be used without particular limitation as long as it serves to improve adhesion between the electrode active material particles and/or adhesion between the electrode active material and a current collector to be described later. In the present application, the binder is, for example, polyvinylidene fluoride (PVDF), vinylidene fluoride-hexfluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol (PVA), polyacrylonitrile ( polyacrylonitrile), carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM , styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one or a mixture of two or more thereof may be used.

The binder may be included, for example, in an amount of about 0.1 to 5 parts by weight based on 100 parts by weight of the electrode active material. In the present application, by including the binder in the same weight part as described above, it is possible to secure the adhesive force between the electrode active material and the current collector at a desired level. In another example, the binder is about 0.2 parts by weight or more, about 0.3 parts by weight or more, about 0.4 parts by weight or more, about 0.5 parts by weight or more, about 0.6 parts by weight or more, about 0.7 parts by weight or more, based on 100 parts by weight of the electrode active material. , about 0.8 parts by weight or more, about 0.9 parts by weight or more, about 1 part by weight or more, about 1.1 parts by weight or more, about 1.2 parts by weight or more, about 1.3 parts by weight or more, about 1.4 parts by weight or more, or about 1.5 parts by weight or more 4.5 parts by weight or less, about 4 parts by weight or less, about 3.5 parts by weight or less, about 3 parts by weight or less, about 2.5 parts by weight or less, about 2 parts by weight or less, about 1.9 parts by weight or less, about 1.8 parts by weight or less, about 1.7 parts by weight It may be included in an amount of up to or less than about 1.6 parts by weight.

In the present application, the solvent is a solvent commonly used in the art, for example, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), isopropyl alcohol (isopropyl alcohol), acetone (acetone) or water, and the like, and either one of them alone or a mixture of two or more thereof may be used. The amount of the solvent used is a viscosity capable of dissolving or dispersing the electrode active material, the conductive material and/or the binder in consideration of the coating thickness of the electrode active material slurry, the production yield, etc., and exhibiting excellent thickness uniformity when applied for subsequent electrode production. It is not particularly limited as long as it is made to have.

The invention may also relate to an electrode.

The electrode of the present application may include, for example, an electrode current collector and an active material layer formed on one surface of the current collector. The electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, carbon on the surface of copper or stainless steel. , nickel, titanium, silver, etc. surface-treated, aluminum-cadmium alloy, etc. may be used. The electrode current collector may typically have a thickness of 3 μm to 500 μm, and may form fine irregularities on the surface of the current collector to enhance bonding strength with the active material layer and the like. The electrode current collector may be used in various forms such as, for example, a film, a sheet, a foil, a net, a porous body, a foam, a non-woven body, and the like.

The active material layer may include, for example, the electrode active material slurry described above, and in this case, the above-described content may be applied to the electrode active material slurry.

The present invention may also relate to an electrochemical device comprising the electrode. The electrochemical device may be, for example, a battery or a capacitor, and more specifically, a lithium secondary battery.

In the present application, the lithium secondary battery may include, for example, a positive electrode, a negative electrode positioned to face the positive electrode, a separator interposed between the positive electrode and the negative electrode, and/or an electrolyte. As the anode, for example, the above-described electrode may be included or used. The lithium secondary battery may further include a battery container for accommodating the electrode assembly such as the positive electrode, the negative electrode, and the separator, and/or a sealing member for sealing the battery container.

In the present application, the negative electrode may include, for example, a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector.

As for the negative electrode current collector, for example, the above-described electrode current collector may be applied in the same manner. The anode active material layer may optionally include a binder and/or a conductive material together with the anode active material.

As the anode active material, a material having a low standard electrode potential, a small structural change due to reaction with lithium ions, and excellent reversibility of reaction with lithium ions, while reversible insertion and desorption of lithium is possible, can be preferably used. and, for example, carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metal compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; metal oxides capable of doping and dedoping lithium, such as SiO _β (0<β<2), SnO ₂ , vanadium oxide, and lithium vanadium oxide; Alternatively, it may be a composite including the above-mentioned metallic compound and a carbonaceous material, such as a Si-C composite or a Sn-C composite, and any one or a mixture of two or more thereof may be used. In another example as the negative active material, a lithium metal thin film; Carbon materials such as low crystalline carbon and high crystalline carbon may be used, and the low crystalline carbon includes natural or artificial graphite of amorphous, plate-like, scale-like, spherical or fibrous shape, Kish graphite, Pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, liquid crystal pitches (Mesophase pitches) and petroleum and coal tar pitch derived cokes and high-temperature calcined carbon such as these can be exemplified. The binder and/or the conductive material may be the same as the binder and/or the conductive material that may be introduced into the electrode active material layer.

In the lithium secondary battery of the present application, the separator is a microporous polymer film having pores having a size of several nm to several μm, and may separate the negative electrode and the positive electrode and provide a passage for lithium ions to move. The separator can be used without any particular limitation as long as it is usually used as a separator in a lithium ion battery. In particular, it is preferable that the separator has low resistance to ion movement of the electrolyte and excellent electrolyte moisture content. The separator is, for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and ethylene/methacrylate copolymer, or two layers thereof. It may be the above laminated structure, or a conventional porous nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, etc. In another example, a coating separator containing a ceramic component or a polymer material is used to secure heat resistance or mechanical strength. may be

In the present application, the electrolyte may be, for example, an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, etc. that can be used in manufacturing a lithium secondary battery, but is limited thereto not.

The electrolyte may include, for example, an organic solvent and/or a lithium salt. The organic solvent may be used without any 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, as the organic solvent, ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon-based solvents such as benzene and fluorobenzene; dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), propylene carbonate (propylene) carbonate-based solvents such as carbonate, PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (R is a C2 to C20 linear, branched or cyclic hydrocarbon group, which may include a double bond aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; Or sulfolane may be used. Among these, a carbonate-based solvent is preferable as the electrolyte, and a cyclic carbonate (eg, ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant capable of increasing the charge/discharge performance of a battery and a low-viscosity linear carbonate A mixture of a system compound (eg, ethylmethyl carbonate, dimethyl carbonate, diethyl carbonate, etc.) is more preferable. In this case, it may be preferable in terms of electrolyte performance to mix and use the cyclic carbonate and the chain carbonate in a volume ratio of about 1:1 to about 1:9.

The lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. The lithium salt is, for example, 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 , LiCl, LiI, or LiB(C ₂ O ₄ ) ₂ , and the like. The concentration of the lithium salt may be preferably used within the range of 0.1 to 2.0M. When the concentration of the lithium salt is within the above range, the electrolyte may exhibit excellent electrolyte performance due to appropriate conductivity and/or viscosity, and the movement of lithium ions may be effective.

In addition to the above components, the electrolyte includes, for example, haloalkylene carbonate-based compounds such as difluoroethylene carbonate, pyridine, and triethylphosphite for the purpose of improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity. , triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, One or more additives such as ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol or aluminum trichloride may be further included. In this case, the additive may be included in an amount of about 0.1 to 5 wt% based on the total weight of the electrolyte.

Since the lithium secondary battery including the electrode according to the present invention exhibits excellent output characteristics, capacity retention and/or excellent conductivity, etc., portable devices such as mobile phones, notebook computers, digital cameras, and hybrid electric vehicles, HEV) and the like may be useful in the field of electric vehicles.

The present invention may also provide, for example, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same. The battery module or battery pack is a power tool (Power Tool); Electric vehicles, including electric vehicles (Electric Vehicles, EVs), hybrid electric vehicles and / or plug-in hybrid electric vehicles (Plug-in Hybrid Electric Vehicle, PHEV); Alternatively, it may be used as a power source for any one or more medium-to-large devices in a system for power storage.

The present application can provide an electrode active material capable of realizing a battery having a high capacity and excellent capacity retention (lifetime characteristics) according to charging and discharging, and having excellent conductivity, a manufacturing method thereof, and the like.

The scope of the present application will be described in more detail through the following examples, but the scope of the present application is not limited by the following examples.

Claims (15)

An active material core, a metal oxide layer formed on the active material core, and a conductive layer formed on the metal oxide layer,
The ratio of the height (H ₁ ) of the metal oxide layer from the surface of the active material core to the height (H ₂ ) of the conductive layer from the surface of the metal oxide layer (H ₁ /H ₂ ) is an electrode in the range of 0.01 to 10 active material. The electrode active material according to claim 1, wherein the conductive layer has a coverage of 50% or more on the surface of the metal oxide layer. The electrode active material of claim 1, wherein the active material core includes lithium nickel-manganese-cobalt oxide represented by the following formula (1), and is in the form of secondary particles:
[Formula 1]
Li _x M _y O ₂
In Formula 1, M is represented by Ni _1-ab Mn _a Co _b , wherein a is in the range of 0.02 to 0.3 in 0.05, b is in the range of 0.02 to 0.3, and 1-ab is in the range of 0.6 to 0.95. , x is in the range of 0.5 to 1.5, and y is 2-x. The method according to claim 1, wherein the metal oxide layer comprises at least one selected from the group consisting of AlO _x , ZrO _x , NbO _x , WO _x , lithium aluminum oxide, lithium zirconium oxide, lithium niobium oxide and lithium tungsten oxide, wherein x is an electrode active material of 0 or more and 3 or less. The electrode active material of claim 1, wherein the conductive layer includes any one or a combination of two or more selected from the group consisting of a carbon material, a metal, a conductive oxide, and a conductive polymer. The electrode active material according to claim 1, wherein the molar content ratio of the metal of the metal oxide layer to the nickel (Ni) of the active material core is in the range of 50 ppm to 10000 ppm. The electrode active material according to claim 1, wherein a height of the metal oxide layer from the surface of the active material core is in the range of 0.2 nm to 5 nm. The electrode active material according to claim 1, wherein the height of the conductive layer from the surface of the metal oxide layer is in the range of 0.5 nm to 20 nm. A first step of forming a metal oxide layer on the active material core through atomic layer deposition (ALD); and a second step of forming a conductive layer on the metal oxide layer through chemical vapor deposition (CVD). 10. The method of claim 9, wherein the atomic layer deposition comprises:
injecting a metal precursor into the chamber in which the active material core is located;
purging the chamber;
injecting an oxidizing agent into the chamber; and
An electrode active material manufacturing method comprising a unit process comprising the step of purging the chamber. The method of claim 9 , wherein the atomic layer deposition is performed by repeating the unit process 1 to 20 times. 10. The method of claim 9, wherein the atomic layer deposition is performed at a temperature in the range of 60°C to 300°C. 10. The method of claim 9, wherein the chemical vapor deposition method,
purging by injecting an inert gas into the chamber in which the active material core on which the metal oxide layer is formed is located;
heating the chamber to a reaction temperature;
injecting a reaction gas into the chamber; and
An electrode active material manufacturing method comprising the step of cooling the chamber. An electrode active material slurry comprising the electrode active material of claim 1 . current collector; and
Including an active material layer formed on one surface of the current collector,
The active material layer is an electrode comprising the electrode active material of claim 1.