Positive electrode active material and method for producing positive electrode active material

Abstract

The present invention relates to a cathode active material for a solid-state battery, the cathode active material comprising Li, M', and oxygen, wherein M' comprises Ti. The present inventors have surprisingly found that the cathode active material of the present invention significantly improves the cycle efficiency of batteries, particularly sulfide solid-state batteries.

Description

[Technical Field]

[0001] The present invention relates to a positive electrode active material for a solid-state battery, comprising Li, M', and oxygen, wherein M' comprises Ti. The present invention also relates to a method for producing the positive electrode active material, a solid-state battery containing the positive electrode active material, and the use of the solid-state battery. [Background technology]

[0002] As the development of small, lightweight electronic products, electronic devices, and communication devices progresses rapidly, and the need for electric vehicles to address environmental issues becomes increasingly apparent, there is a growing demand for improved performance in rechargeable batteries used as power sources for these products. Among these, lithium-ion batteries are attracting attention as high-performance batteries due to their high energy density and high reference electrode potential.

[0003] During the charging process of a secondary battery, lithium ions are removed from the cathode, transported through the electrolyte, and inserted into the anode, while electrons are removed from the cathode and injected into the anode via an external circuit (charger). During use or discharge of the secondary battery, lithium ions are removed from the anode, transported through the electrolyte, and inserted into the cathode, while electrons flow through the external circuit, providing electrical work.

[0004] Commonly used cathode active materials are lithium transition metal oxides. During charging and / or discharging of lithium batteries, delithiated cathode active materials slowly react with non-aqueous or solid electrolytes, potentially leading to a gradual decrease in the electrochemical performance of lithium batteries using such cathode active materials. It has been demonstrated that treating the cathode active material with a metal such as Ti or Zr (i.e., applying a thin surface layer of the metal to the cathode active material to increase the amount of the metal in the surface layer) results in a cathode active material that exhibits higher stability compared to counterparts without such a surface layer.

[0005] Chinese Patent No. 109742376(A) discloses a Ti-treated cathode active material containing 83% nickel, 5% manganese, and 12% cobalt, which is obtained by dry-treating the cathode active material with 0.1% by weight of TiO2.

[0006] In U.S. Patent Application Publication No. 2019 / 0006662(A1), 60% The invention aims to create a Ti-treated positive electrode active material containing nickel, 20% manganese, and 20% cobalt. The treated positive electrode active material is obtained by treating the positive electrode active material with titanium butoxide in EtOH. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The drawbacks associated with these known Ti-treated cathode active materials are the low cycle efficiency and / or low initial discharge capacity of batteries containing them. Therefore, there remains a need to provide cathode active materials having an enriched amount of Ti in the surface layer in order to improve the cycle efficiency of the resulting batteries.

[0008] The object of the present invention is to provide a positive electrode active material having an enriched amount of Ti in the surface layer that improves the cycle efficiency of the resulting battery.

[0009] Another object of the present invention is to provide a method for producing the positive electrode active material.

[0010] Another object of the present invention is to provide a battery containing the positive electrode active material.

[0011] Another object of the present invention is to provide a use for the battery. [Means for solving the problem]

[0012] In the first embodiment, the object of the present invention is a positive electrode active material for a solid-state battery, wherein the positive electrode active material comprises Li, M', and oxygen, and M' is Ni with content x such that 55.0 mol% ≤ x ≤ 98.0 mol%, The Mn content y is such that 0.0 mol% ≤ y ≤ 45.0 mol%, Co with a content of z such that 0.0 mol% ≤ z ≤ 45.0 mol%, A D having a content a such that 0.0 mol% ≤ a ≤ 5.0 mol%, and D being at least one element other than Li, Ni, Mn, Co, Ti, and O, It contains Ti with a content of b such that 0.01 mol% ≤ b ≤ 5.0 mol%, x, y, z, a, and b were measured by ICP-OES. x+y+z+a+b is 100.0 mol%, This is achieved by providing a positive electrode active material having an enriched amount of Ti in its surface layer.

[0013] The inventors have surprisingly found that the positive electrode active material of the present invention significantly improves the cycle efficiency of batteries, particularly sulfide solid-state batteries. Furthermore, the positive electrode active material of the present invention exhibits a high initial discharge capacity. Preferably, the treated positive electrode active material containing polycrystalline particles performs better in terms of cycle efficiency than the corresponding single-crystal positive electrode active material or positive electrode active material containing single and / or secondary particles as defined herein.

[0014] While not bound by any particular theory, the inventors believe that in order to obtain a lithium titanium oxide compound as an effective treatment for the cathode active material, it is necessary to add a Li source along with a Ti source as a treatment agent.

[0015] In a further embodiment, the present invention provides a method for producing the positive electrode active material.

[0016] In a further embodiment, the present invention provides a battery comprising the positive electrode active material.

[0017] In a further embodiment, the present invention provides a use for the battery. [Modes for carrying out the invention]

[0018] In the following embodiments for carrying out the invention, preferred embodiments for realizing the invention are described in detail. Although the invention is described with reference to these particular preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. Conversely, the invention includes a number of substitutes, modifications and equivalents, as will become apparent from considering the following embodiments for carrying out the invention and the accompanying drawings.

[0019] As used herein and in the claims, the term “comprising” should not be construed as limiting to the means enumerated thereafter, nor should it exclude other elements or steps. It should be construed as indicating the presence of the features, integers, steps, or components described as mentioned, but not as excluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Accordingly, the expression “composition comprising components A and B” should not be limited to a composition consisting solely of components A and B. It means, with respect to the present invention, that A and B are the only relevant components of the composition. Thus, the terms “comprising” and “including” encompass the more restrictive terms “consisting essentially of” and “consisting of.”

[0020] As used herein and in the claims, the term “solid-state battery” refers to a cell or battery that comprises only solid or substantially solid components, such as solid electrodes (e.g., anode and cathode) and a solid electrolyte.

[0021] As used herein and in the claims, the term “positive electrode active material” (also known as “cathode active material”) is defined as a material that is electrochemically active at the positive electrode or cathode. An active material should be understood as a material that can capture and release Li ions when exposed to a voltage change over a given period of time.

[0022] As used herein and in the claims, the term “slurry” refers to a mixture, premixture, and / or admixture of solid particles suspended in a liquid, such as water, alcohol, or a combination thereof. When the term “slurry” is used, the solid particles are not dissolved or not completely dissolved in the liquid. For example, a slurry of lithium transition metal oxide compounds is a suspension in a liquid of the particles that make up the lithium transition metal oxide compound. In other words, the particles that make up the lithium transition metal oxide compound are not dissolved or not completely dissolved in the liquid.

[0023] In the context of this invention, the terms “solid” and “liquid” shall, unless otherwise defined, be considered to be solid and liquid under standard conditions for temperature and pressure as defined by IUPAC. Accordingly, the boiling point and melting point shall be considered to be the boiling point and melting point at standard atmospheric pressure, i.e., 101325 Pa.

[0024] positive electrode active material In a first embodiment, the present invention relates to a positive electrode active material for a solid-state battery, wherein the positive electrode active material comprises Li, M', and oxygen, and M' is Ni with content x such that 55.0 mol% ≤ x ≤ 98.0 mol%, The Mn content y is such that 0.0 mol% ≤ y ≤ 45.0 mol%, Co with a content of z such that 0.0 mol% ≤ z ≤ 45.0 mol%, A D having a content a such that 0.0 mol% ≤ a ≤ 5.0 mol%, and D being at least one element other than Li, Ni, Mn, Co, Ti, and O, It contains Ti with a content b of 0.01 mol% ≤ b ≤ 5.0 mol%. x, y, z, a, and b are measured by ICP - OES. Regarding the positive electrode active material, x + y + z + a + b = 100.0 mol%.

[0025] A specific preferred embodiment is the positive electrode active material of the present invention, where the content of Ni is x ≥ 60.0 mol%, preferably x ≥ 61.0 mol%, more preferably x ≥ 62.0 mol%. In a specific preferred embodiment, the content of Ni is x ≤ 90.0 mol%, preferably x ≤ 88 mol%, more preferably x ≤ 85.0 mol%. A more preferred specific embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is 55.0 mol% ≤ x ≤ 75.0 mol%, preferably 60.0 mol% ≤ x ≤ 70.0 mol%, more preferably 62.0 mol% ≤ x ≤ 68.0 mol%. Another more preferred specific embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is 60.0 mol% ≤ x ≤ 90.0 mol%, preferably 61.0 mol% ≤ x ≤ 88.0 mol%, more preferably 62.0 mol% ≤ x ≤ 85.0 mol%.

[0026] A more preferred specific embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is x ≥ 75.0 mol%, preferably x ≥ 76.0 mol%, more preferably x ≥ 77.0 mol%. A more preferred specific embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is x ≤ 95.0 mol%, preferably x ≤ 90.0 mol%, more preferably x ≤ 88.0 mol%. A more preferred specific embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is 75.0 mol% < x ≤ 95.0 mol%, preferably 76.0 mol% ≤ x ≤ 90.0 mol%, more preferably 77.0 mol% ≤ x ≤ 88.0 mol%.

[0027] As will be understood by those skilled in the art, the amounts of Li and M' in the positive electrode active material, preferably Li, Ni, Mn, Co, D, and Ti, are measured by inductively coupled plasma optical emission spectrometry (ICP-OES). For example, without being limited to the present invention, Agilent ICP 720-ES is used in ICP-OES analysis.

[0028] A preferred embodiment is the positive electrode active material of the present invention, wherein the content of Mn is y > 0.0 mol%, preferably y ≥ 3.0 mol%, more preferably y ≥ 5.0 mol%. In a preferred embodiment, the content is y ≤ 30.0 mol%, preferably y ≤ 20.0 mol%, more preferably y ≤ 15.0 mol%. In a preferred embodiment, the content of Mn is 0.0 mol% < y ≤ 30.0 mol%, preferably 3.0 mol% ≤ y ≤ 20.0 mol%, more preferably 5.0 mol% ≤ y ≤ 15.0 mol%.

[0029] A preferred embodiment is the positive electrode active material of the present invention, wherein the content of Co is z > 0.0 mol%, preferably z ≥ 1.0 mol%, more preferably z ≥ 3.0 mol%. In a preferred embodiment, the content z ≤ 30.0 mol%, preferably z ≤ 20.0 mol%, more preferably z ≤ 15.0 mol%. In a preferred embodiment, the content is 0.0 mol% < z ≤ 30.0 mol%, preferably 1.0 mol% ≤ z ≤ 20.0 mol%, more preferably 3.0 mol% ≤ z ≤ 15.0 mol%.

[0030] As is known to those skilled in the art, the positive electrode active material of the present invention may contain impurities or may be doped or added to the surface layer. As a result, the positive electrode active material as a whole contains one or more elements other than Li, Ni, Mn, Co, Ti, and O, which is reflected in the parameter "D" used in this specification. A preferred embodiment is a positive electrode active material of the present invention that contains D, which is at least one element selected from the group consisting of Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W.

[0031] A preferred embodiment is a positive electrode active material according to the present invention, in which the content of D is a > 0.0 mol%, preferably a ≥ 0.25 mol%, more preferably a ≥ 0.5 mol%. In a preferred embodiment, the content a ≤ 2.0 mol%, preferably a ≤ 1.75 mol%, more preferably a ≤ 1.5 mol%. In a preferred embodiment, the content is 0.0 mol% < a ≤ 2.0 mol%, preferably 0.25 mol% ≤ a ≤ 1.75 mol%, more preferably 0.5 mol% ≤ a ≤ 1.5 mol%.

[0032] A preferred embodiment is a positive electrode active material of the present invention, in which the content of Ti is b ≥ 0.01 mol%, preferably b ≥ 0.05 mol%, more preferably b ≥ 0.10 mol%. In a preferred embodiment, b ≤ 2.5 mol%, preferably b ≤ 2.0 mol%, more preferably b ≤ 1.0 mol%. In a preferred embodiment, 0.01 mol% ≤ b ≤ 2.5 mol%, preferably 0.05 mol% ≤ b ≤ 2.0 mol%, more preferably 0.10 mol% ≤ b ≤ 1.0 mol%.

[0033] A preferred embodiment is the positive electrode active material of the present invention having a carbon content of more than 0.020% by weight, preferably more than 0.030% by weight, and more preferably more than 0.045% by weight, relative to the total weight of the positive electrode active material. A preferred embodiment is the positive electrode active material of the present invention having a carbon content of less than 0.10% by weight, preferably less than 0.080% by weight, and more preferably less than 0.065% by weight, relative to the total weight of the positive electrode active material. A preferred embodiment is the positive electrode active material of the present invention having a carbon content in the range of 0.020% to 0.10% by weight, preferably in the range of 0.030% to 0.080% by weight, and more preferably in the range of 0.045% to 0.065% by weight, relative to the total weight of the positive electrode active material. As those skilled in the art will understand, the carbon content can be analyzed with a carbon analyzer. For example, although not limited to the present invention, a Horiba Emia-Expert carbon / sulfur analyzer can be used.

[0034] A preferred embodiment is the positive electrode active material of the present invention, wherein the Li / M' ratio, preferably the Li / (Ni+Mn+Co) ratio, is greater than 0.90, preferably greater than 0.92, and more preferably greater than 0.95. A preferred embodiment is the positive electrode active material of the present invention, wherein the Li / M' ratio, preferably the Li / (Ni+Mn+Co) ratio, is less than 1.10, preferably less than 1.08, and more preferably less than 1.05. A preferred embodiment is the positive electrode active material of the present invention, wherein the Li / M' ratio, preferably the Li / (Ni+Mn+Co) ratio, is in the range of 0.90 to 1.10, preferably in the range of 0.92 to 1.08, and more preferably in the range of 0.95 to 1.05. As those skilled in the art will understand, the Li / M' ratio, preferably the Li / (Ni+Mn+Co) ratio, is a molar ratio (mol / mol).

[0035] In a very preferred embodiment, the positive electrode active material is Li w2 Ni x2 Mn y2 Co z2 D a2 Ti b2 O2 [in the formula, 0.90 ≤ w2 ≤ 1.10, preferably 0.92 ≤ w2 ≤ 1.1, more preferably 0.95 ≤ w2 ≤ 1.05; 0.55 ≤ x² ≤ 0.98, preferably 0.60 ≤ x² ≤ 0.88, more preferably 0.65 ≤ x² ≤ 0.85; 0.0 ≤ y² ≤ 0.45, preferably 0.03 ≤ y² ≤ 0.20, more preferably 0.05 ≤ y² ≤ 0.10; 0.0 ≤ z² ≤ 0.45, preferably 0.03 ≤ z² ≤ 0.20, more preferably 0.05 ≤ z² ≤ 0.10; 0.0 ≤ a2 ≤ 0.02, preferably 0.025 ≤ a2 ≤ 0.0175, more preferably 0.005 ≤ a2 ≤ 0.015; 0.001≦b2≦0.025, preferably 0.005≦b2≦0.02, more preferably 0.01≦b2≦0.1, This is due to the fact that x² + y² + z² + a² + b² = 1.00.

[0036] In a very preferred embodiment, 0.99 ≤ w2 ≤ 1.01, and preferably w2 is about 1.00.

[0037] In a very preferred embodiment, 0.75 ≤ x2 ≤ 0.85, preferably 0.80 ≤ x2 ≤ 0.85, and more preferably x2 is about 0.83.

[0038] In a very preferred embodiment, 0.06 ≤ y2 ≤ 0.08, and preferably y2 is about 0.07.

[0039] In a very preferred embodiment, 0.08 ≤ z2 ≤ 0.10, and preferably z2 is about 0.09.

[0040] In a very preferred embodiment, 0.0 ≤ a2 ≤ 0.01, and preferably a2 is about 0.0.

[0041] In a very preferred embodiment, 0.01 ≤ b2 ≤ 0.05, and preferably b2 is about 0.01.

[0042] Surface layer A preferred embodiment is a positive electrode active material of the present invention, wherein the positive electrode active material has

[0043]

Number

[0044] a Ti content Ti defined as A and the positive electrode active material has a Ti content Ti determined by XPS analysis B and Ti B is expressed as a molar fraction compared with the total molar fraction of Co, Mn, Ni and Ti measured by XPS analysis, and the specific Ti B / Ti A > 25, relating to the positive electrode active material.

[0045] A more preferred embodiment is that the specific Ti B / Ti A > 50.0, preferably the specific Ti B / Ti A > 75.0, more preferably the specific Ti B / Ti A > 100.0, even more preferably the specific Ti B / Ti A > 125.0, most preferably the specific Ti B / Ti A > 150.0, relating to the positive electrode active material of the present invention.

[0046] <00007​​​​​​​​​​​​​​​​​​​​​

[0047] A more preferred embodiment is a ratio Ti B / Ti A The ratio is in the range of 50.0 to 1000, preferably with respect to Ti B / Ti A The ratio is in the range of 75.0 to 500.0, and more preferably Ti B / Ti A The present invention relates to a positive electrode active material in which the value is in the range of 100.0 to 250.0.

[0048] In the context of the present invention, Ti B This is the mole fraction of Ti measured in a region defined between a first point on the outer edge of a particle of the positive electrode active material according to the present invention and a second point at a certain distance from the first point. The distance between the first point and the second point is equal to the penetration depth of the XPS, and the penetration depth D' is 1.0 to 10.0 nm. In particular, the penetration depth is the distance along an axis perpendicular to a virtual line that is tangent to the outer edge and passes through the first point.

[0049] The outer edge of a particle is, within the framework of this invention, the boundary or external limit that distinguishes the particle from its external environment. Therefore, XPS analysis provides the atomic content of elements in the uppermost layer of the particle at a penetration depth of approximately 10.0 nm from the outer edge of the particle. The outer edge of the particle is also called the "surface." For example, although not limited to this invention, XPS analysis is performed using a Thermo K-α+ spectrometer (Thermo Scientific).

[0050] Within the framework of this invention, atomic % means atomic percentage. Atomic % or "atomic percent" as a concentration expression for a given element means what percentage of all atoms in the compound in question are atoms of that element. Furthermore, within the framework of this invention, an expression in atomic % is equivalent to mol% or "mol percent".

[0051] As those skilled in the art will understand, the defined ratio Ti B / Ti AThis refers to the fact that the positive electrode active material of the present invention has an enriched amount of Ti in its surface layer. The surface layer of the positive electrode active material is the top 1 to 10 nm of the positive electrode active material. In other words, the positive electrode active material of the present invention constitutes the Ti surface layer.

[0052] In the context of the present invention, the positive electrode active material constitutes a first surface layer containing D, where D is Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably at least one element selected from the group consisting of B, Nb, Zr, and W, and the Ti surface layer may be disposed on the first surface layer and / or the first surface layer may be disposed on the Ti surface layer and / or the positive electrode active material layer may include a mixed surface layer containing the Ti surface layer and the first surface layer.

[0053] A preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material has a Li content determined by ICP analysis. A It has, A This is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti measured by ICP analysis, and the Li content of the positive electrode active material is determined by XPS analysis. B It has, B This relates to the positive electrode active material, expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti measured by XPS analysis.

[0054] A preferred embodiment is a specific Li B / Li A The present invention relates to a positive electrode active material that is >1.0.

[0055] A more preferred embodiment is a specific Li B / Li A >2.0, preferably specific Li B / Li A >2.5, more preferably relative Li B / Li A >3.0, even more preferably relative Li B / LiA >3.5, most preferably specific Li B / Li A The present invention relates to a positive electrode active material that is >4.0.

[0056] A more preferred embodiment is a specific Li B / Li A <60.0, preferably relative Li B / Li A <45.0, Lithium content B / Li A <30.0, even more comfortable than Li B / Li A <20.0, most preferably specific Li B / Li A The present invention relates to a positive electrode active material that is <10.0.

[0057] A more preferred embodiment is a specific Li B / Li A ga / Li A The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li A The present invention relates to a positive electrode active material having a value of 4.0 to 10.0.

[0058] In the context of the present invention, Li B This is the mole fraction of Li measured in a region defined between a first point on the outer edge of a particle of the positive electrode active material according to the present invention and a second point at a certain distance from the first point. The distance between the first point and the second point is equal to the penetration depth of the XPS, and the penetration depth D' is 1.0 to 10.0 nm. In particular, the penetration depth is the distance along an axis perpendicular to a virtual line that is tangent to the outer edge and passes through the first point.

[0059] As those skilled in the art will understand, the defined ratio Li B / Li AIt means that the cathode active material of the present invention has an amount of Li enriched in the surface layer of the cathode active material. The surface layer of the cathode active material is the uppermost 1 - 10 nm of the cathode active material. In other words, the cathode active material of the present invention constitutes the surface layer of Li.

[0060] In the context of the present invention, the cathode active material can constitute a second surface layer containing D, and D is Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr; preferably, Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably, at least one element selected from the group consisting of B, Nb, Zr, and W. The surface layer of Li may be disposed on the second surface layer, and / or the second surface layer may be disposed on the surface layer of Li, and / or the cathode active material layer may include a mixed surface layer containing the surface layer of Li and the second surface layer.

[0061] A preferred embodiment relates to the cathode active material of the present invention having a ratio of Li B / Ti B > 1.0.

[0062] A more preferred embodiment is that the ratio of Li B / Ti B > 2.0, preferably the ratio of Li B / Ti B > 3.0, more preferably the ratio of Li B / Ti B > 4.0, even more preferably the ratio of Li B / Ti B > 5.0, most preferably the ratio of Li B / Ti B > 6.0, relating to the cathode active material of the present invention.

[0063] A more preferred embodiment is that the ratio of Li B / Ti B < 100.0, preferably the ratio of Li B / Ti B < 60.0, more preferably the ratio of Li B / Ti B < 45.0, even more preferably the ratio of Li B / Ti B<30.0, most preferably the ratio of Li B / Ti B is <10.0, relating to the positive electrode active material of the present invention.

[0064] A more preferred embodiment is that the ratio of Li B / Ti B is 2.0 to 60.0, preferably the ratio of Li B / Ti B is 4.0 to 30.0, more preferably the ratio of Li B / Ti B is 6.0 to 10.0, relating to the positive electrode active material of the present invention.

[0065] As will be understood by those skilled in the art, the defined ratio of Li B / Ti B means that the positive electrode active material of the present invention has a specific amount of Li and Ti in the surface layer of the positive electrode active material. The surface layer of the positive electrode active material is the uppermost 1 to 10 nm of the positive electrode active material.

[0066] In the context of the present invention, the positive electrode active material can constitute a third surface layer containing D, and D is Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr; preferably, Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably, at least one element selected from the group consisting of B, Nb, Zr, and W. The surface layers of Ti and Li may be disposed on the third surface layer, and / or the third surface layer may be disposed on the surface layers of Ti and Li, and / or the positive electrode active material layer may include a mixed surface layer including the surface layers of Ti and Li and the third surface layer.

[0067] A specific preferred embodiment is the ratio of Ti B / Ti A >25.0, and the ratio of Li B / Li A >1.0, relating to the positive electrode active material of the present invention.

[0068] A specific preferred embodiment is the ratio of Ti B / Ti A >50.0, preferably relative Ti B / Ti A >75.0, more preferably relative to Ti B / Ti A >100.0; and Filipino Li B / Li A >2.0, preferably specific Li B / Li A >3.0, more preferably relative to Li B / Li A The present invention relates to a positive electrode active material that is >4.0.

[0069] A particular preferred embodiment is: ratio Ti B / Ti A <1000.0, preferably relative to Ti B / Ti A <500.0, Comfort ratio Ti B / Ti A <250.0; and Filipino Li B / Li A <60.0, preferably relative Li B / Li A <30.0, Lithium-ion of the light source B / Li A The present invention relates to a positive electrode active material that is <10.0.

[0070] A particular preferred embodiment is: ratio Ti B / Ti A The ratio is in the range of 50.0 to 1000, preferably with respect to Ti B / Ti A The ratio is in the range of 75.0 to 500.0, and more preferably Ti B / Ti A The range is between 100.0 and 250.0; Filipino Li B / Li A The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li AThe present invention relates to a positive electrode active material having a value of 4.0 to 10.0.

[0071] A particular preferred embodiment is: ratio Ti B / Ti A >25.0, and Filipino Li B / Ti B The present invention relates to a positive electrode active material that is >1.0.

[0072] A particular preferred embodiment is: ratio Ti B / Ti A >50.0, preferably relative Ti B / Ti A >75.0, more preferably relative to Ti B / Ti A >100.0; and Filipino Li B / Ti B >2.0, preferably specific Li B / Ti B >4.0, most preferably relative Li B / Ti B The present invention relates to a positive electrode active material that is >6.0.

[0073] A particular preferred embodiment is: ratio Ti B / Ti A <1000.0, preferably relative to Ti B / Ti A <500.0, Comfort ratio Ti B / Ti A <250.0; and Filipino Li B / Ti B <100.0, preferably relative Li B / Ti B <30.0, Lithium-ion of the light source B / Ti B The present invention relates to a positive electrode active material that is <10.0.

[0074] A particular preferred embodiment is: ratio Ti B / Ti Ais within the range of 50.0 to 1000, preferably the ratio Ti B / Ti A is within the range of 75.0 to 500.0, more preferably the ratio Ti B / Ti A is within the range of 100.0 to 250.0; The ratio Li B / Li A is 2.0 to 60.0, preferably the ratio Li B / Li A is 3.0 to 30.0, more preferably the ratio Li B / Li A is 4.0 to 10.0, relating to the positive electrode active material of the present invention.

[0075] Specific preferred embodiments are The ratio Li B / Li A > 1.0, and The ratio Li B / Ti B > 1.0, relating to the positive electrode active material of the present invention.

[0076] Specific preferred embodiments are The ratio Li B / Li A > 2.0, preferably the ratio Li B / Li A > 3.0, more preferably the ratio Li[[ID=X]] B / Li A > 4.0; and The ratio Li B [[ID=X]] / Ti B > 2.0, preferably the ratio Li B / Ti B > 4.0, more preferably the ratio Li B / Ti B > 6.0, relating to the positive electrode active material of the present invention.

[0077] Specific preferred embodiments are The ratio Li B / Li A < 60.0, preferably the ratio Li B / Li A < 30.0, more preferably the ratio Li B / Li It should be noted that there seems to be a duplicate ID "X" in the original text which might be a mistake. I've translated it as is while keeping the tags intact. If you have any further clarifications or corrections regarding the text, please let me know.A <10.0; and Filipino Li B / Ti B <100.0, preferably relative Li B / Ti B <30.0, Lithium-ion of the light source B / Ti B The present invention relates to a positive electrode active material that is <10.0.

[0078] A particular preferred embodiment is: Filipino Li B / Li A The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li A The range is 4.0 to 10.0. Filipino Li B / Li A The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li A The present invention relates to a positive electrode active material having a value of 4.0 to 10.0.

[0079] A particular preferred embodiment is: ratio Ti B / Ti A >25.0; Filipino Li B / Li A >1.0, and Filipino Li B / Ti B The present invention relates to a positive electrode active material that is >1.0.

[0080] A particular preferred embodiment is: ratio Ti B / Ti A >50.0, preferably relative Ti B / Ti A >75.0, more preferably relative to Ti B / Ti A >100.0; Filipino LiB / Li A >2.0, preferably specific Li B / Li A >3.0, more preferably relative to Li B / Li A >4.0; and Filipino Li B / Ti B >2.0, preferably specific Li B / Ti B >4.0, more comfortably compared to Li B / Ti B The present invention relates to a positive electrode active material that is >6.0.

[0081] A particular preferred embodiment is: ratio Ti B / Ti A <1000.0, preferably relative to Ti B / Ti A <500.0, Comfort ratio Ti B / Ti A <250.0; Filipino Li B / Li A <60.0, preferably relative Li B / Li A <30.0, Lithium-ion of the light source B / Li A <10.0; and Filipino Li B / Ti B <100.0, preferably relative Li B / Ti B <30.0, most preferably relative Li B / Ti B The present invention relates to a positive electrode active material that is <10.0.

[0082] A particular preferred embodiment is: ratio Ti B / Ti A The ratio is in the range of 50.0 to 1000, preferably with respect to Ti B / Ti A The ratio is in the range of 75.0 to 500.0, and more preferably Ti B / Ti A The range is 100.0 to 250.0. Filipino Li B / Li A The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li A The range is 4.0 to 10.0. Filipino Li B / Ti B The ratio is 2.0 to 60.0, preferably with respect to Li B / Li A The ratio is 3.0 to 30.0, and more preferably specific Li B / Li A The present invention relates to a positive electrode active material having a value of 4.0 to 10.0.

[0083] form In certain preferred embodiments, the positive electrode active material of the present invention comprises single-crystal particles. In the context of the present invention, particles are considered to be single crystals if they consist of only one crystal grain, or at most five crystal grains, preferably at most three crystal grains, as observed by scanning electron microscopy (SEM) or transmission electron microscopy (TEM), preferably by observing the grain boundaries of the particles. A grain boundary is defined as the interface between two crystal grains within a particle, preferably where the atomic planes of the two crystal grains are aligned in different directions and intersect as a discontinuity in the crystal. As those skilled in the art will understand, in the context of the present invention, the positive electrode active material has an area of ​​at least 45 μm × at least 60 μm (i.e., at least 2700 μm) in the SEM image. 2 ), preferably at least 100 μm × 100 μm (i.e., at least 10,000 μm) 2 The SEM includes single-crystal particles, where more than 80% of the particles within its field of view are single crystals. In determining single-crystal particles, crystal grains with the largest linear dimension observed by the SEM that are smaller than 20% of the median particle size D50 of the particle determined by laser diffraction are ignored. This prevents particles that are essentially single crystals but may have several very small other crystal grains attached from being mistakenly considered not to be single crystals.

[0084] In a particular preferred embodiment, the positive electrode active material of the present invention comprises single crystal particles having a carbon content of more than 0.020% by weight, preferably more than 0.025% by weight, and more preferably more than 0.030% by weight, relative to the total weight of the positive electrode active material. In a particular preferred embodiment, the positive electrode active material of the present invention comprises single crystal particles having a carbon content of less than 0.050% by weight, preferably less than 0.040% by weight, and more preferably less than 0.035% by weight, relative to the total weight of the positive electrode active material. In a particular preferred embodiment, the positive electrode active material of the present invention comprises single crystal particles having a carbon content in the range of 0.020% to 0.050% by weight, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.035% by weight, relative to the total weight of the positive electrode active material.

[0085] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Li A >2.0, preferably specific Li B / Li A >2.5, more preferably relative Li B / Li A It contains single crystal particles with a specific Li ratio of >3.0. In certain preferred embodiments, the positive electrode active material of the present invention is a specific Li ratio. B / Li A <8.0, preferably relative Li B / Li A <7.0, Lithium-ionized refrigerant B / Li A It contains single crystal particles with a specific Li ratio <6.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Li A The ratio is in the range of 2.0 to 8.0, preferably with respect to Li B / Li A The ratio is in the range of 2.5 to 7.0, and more preferably, specific Li B / Li A It includes single crystal grains in the range of 3.0 to 6.0.

[0086] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Ti B >2.0, preferably specific Li B / Ti B >2.5, more preferably relative Li B / Ti B It contains single crystal particles with a specific Li ratio of >3.0. In certain preferred embodiments, the positive electrode active material of the present invention is a specific Li ratio. B / Ti B <7.0, preferably relative Li B / Ti B <6.0, Lithium content B / Ti B It contains single crystal particles with a specific Li ratio <5.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Ti B The ratio is in the range of 2.0 to 7.0, preferably with respect to Li B / Ti B The ratio is in the range of 2.5 to 6.0, and more preferably, specific Li B / Ti B It includes single crystal grains where the coefficient is in the range of 3.0 to 5.0.

[0087] A particular preferred embodiment is the positive electrode active material of the present invention, Contains single crystal particles, The carbon content is in the range of 0.020% to 0.50% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.050% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Li A The ratio is in the range of 2.0 to 8.0, preferably with respect to Li B / Li A The ratio is in the range of 2.5 to 7.0, and more preferably, specific Li B / Li A This relates to positive electrode active materials where the value is in the range of 3.0 to 6.0.

[0088] A particular preferred embodiment is the positive electrode active material of the present invention, containing single crystal particles, having a carbon content in the range of 0.020 wt% to 0.50 wt%, preferably in the range of 0.025 wt% to 0.040 wt%, more preferably in the range of 0.030 wt% to 0.050 wt% based on the total weight of the positive electrode active material, Specifically, Li B / Ti B is in the range of 2.0 to 7.0, preferably Li B / Ti B is in the range of 2.5 to 6.0, more preferably Li B / Ti B is in the range of 3.0 to 5.0, relating to the positive electrode active material.

[0089] A specific preferred embodiment is a positive electrode active material, containing single crystal particles, having a carbon content in the range of 0.020 wt% to 0.50 wt%, preferably in the range of 0.025 wt% to 0.040 wt%, more preferably in the range of 0.030 wt% to 0.050 wt% based on the total weight of the positive electrode active material, Specifically, Li B / Li A is in the range of 2.0 to 8.0, preferably Li B / Li A is in the range of 2.5 to 7.0, more preferably Li B / Li A is in the range of 3.0 to 6.0, Specifically, Li B / Ti B is in the range of 2.0 to 7.0, preferably Li B / Ti B is in the range of 2.5 to 6.0, more preferably Li B / Ti B is in the range of 3.0 to 5.0, relating to the positive electrode active material.

[0090] A specific preferred embodiment is a positive electrode active material, containing single crystal particles, The Co content of the particles was measured at the edges of the particles by cross-sectional EDS (CS-EDS). edge Co edge However, this is expressed as mol% of the total Ni, Mn, and Co content measured by CS-EDS at the edges of the particle, and the Co content measured by CS-EDS at the center of the particle. center Co center However, it is expressed as mol% relative to the total Ni, Mn, and Co content measured by CS-EDS at the center of the particle, and specific Co edge / Co center >1.10, preferably Co edge / Co center >1.20, more preferably Co edge / Co center >1.30, most preferably Co edge / Co center Regarding the positive electrode active material, the value is >1.50.

[0091] In the framework of this invention, the edges of a particle are boundaries or external limits that distinguish the particle from its external environment. The center of a particle is the midpoint of the longest straight line connecting the two points at the edges of the particle.

[0092] A particular preferred embodiment is a positive electrode active material, Contains single crystal particles, Particles,

[0093]

number

[0094] Al content is defined as [wherein c is the Al content measured by XPS] A The positive electrode active material has an Al content determined by XPS analysis. B It has Al B This is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Al measured by XPS analysis, and the specific Al B / Al A>1.0, preferably relative to Al B / Al A >2.0, more preferably relative to Al B / Al A >2.5, more preferably relative to Al B / Al A >3.0, more preferably relative to Al B / Al A >3.5, most preferably relative to Al B / Al A Regarding the positive electrode active material, which is >4.0.

[0095] A particular preferred embodiment is a positive electrode active material, Contains single crystal particles, The Co content of the particles was measured at the edges of the particles by cross-sectional EDS (CS-EDS). edge Co edge However, this is expressed as mol% of the total Ni, Mn, and Co content measured by CS-EDS at the edges of the particle, and the Co content measured by CS-EDS at the center of the particle. center Co center However, it is expressed as mol% relative to the total Ni, Mn, and Co content measured by CS-EDS at the center of the particle, and specific Co edge / Co center >1.10, preferably Co edge / Co center >1.20, more preferably Co edge / Co center >1.30, most preferably Co edge / Co center >1.50, Particles,

[0096]

number

[0097] Al content is defined as [wherein c is the Al content measured by XPS] A The positive electrode active material has an Al content determined by XPS analysis.B It has Al B This is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Al measured by XPS analysis, and the specific Al B / Al A >1.0, preferably relative to Al B / Al A >2.0, more preferably relative to Al B / Al A >2.5, more preferably relative to Al B / Al A >3.0, more preferably relative to Al B / Al A >3.5, most preferably relative to Al B / Al A Regarding the positive electrode active material, which is >4.0.

[0098] In certain preferred embodiments of the present invention and in the context of the present invention, single-crystal particles as defined herein are monolithic particles. As those skilled in the art will understand, in these particular preferred embodiments, all embodiments relating to single-crystal particles are equally applicable to monolithic particles as defined herein.

[0099] In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles, each of which, as observed in SEM images, consists of only one primary particle, and each of which consists of at least two primary particles and at most 20 primary particles. Preferably, at least 30%, more preferably at least 50%, of the particles constituting the powder observed in SEM images are single particles and / or secondary particles. The number of primary particles constituting the single particles and / or secondary particles is at least 45 μm × at least 60 μm (i.e., at least 2700 μm). 2 ), preferably at least 100 μm × 100 μm (i.e., at least 10,000 μm) 2 It is required within the scope of ).

[0100] The particles in the image must be properly dispersed, and thus overlap between particles must be avoided. This can be achieved by applying a small amount of powder sample to an adhesive attached to the SEM sample holder and blowing air to remove excess powder. In the context of the present invention, primary particles are distinguished from each other in the SEM image by observing the grain boundaries between primary particles. A grain boundary is defined as the interface between two primary particles, preferably where the atomic planes of the two primary particles are aligned in different directions and intersect as a discontinuity in the crystal.

[0101] In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles having a carbon content of more than 0.020% by weight, preferably more than 0.025% by weight, and more preferably more than 0.030% by weight, relative to the total weight of the positive electrode active material. In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles having a carbon content of less than 0.050% by weight, preferably less than 0.040% by weight, and more preferably less than 0.035% by weight, relative to the total weight of the positive electrode active material. In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles having a carbon content in the range of 0.020% to 0.050% by weight, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.035% by weight, relative to the total weight of the positive electrode active material.

[0102] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Li A >2.0, preferably specific Li B / Li A >2.5, more preferably relative Li B / Li A It comprises single particles and / or secondary particles, with a specific Li ratio >3.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Li A <8.0, preferably relative Li B / LiA <7.0, Lithium-ionized refractory B / Li A It comprises single particles and / or secondary particles having a specific Li ratio <6.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Li A The ratio is in the range of 2.0 to 8.0, preferably with respect to Li B / Li A The ratio is in the range of 2.5 to 7.0, and more preferably, specific Li B / Li A This includes single particles and / or secondary particles, where the coefficient is in the range of 3.0 to 6.0.

[0103] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Ti B >2.0, preferably specific Li B / Ti B >2.5, more preferably relative Li B / Ti B It comprises single particles and / or secondary particles, with a specific Li ratio >3.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Ti B <7.0, preferably relative Li B / Ti B <6.0, Lithium content B / Ti B It comprises single particles and / or secondary particles having a specific Li ratio <5.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Ti B The ratio is in the range of 2.0 to 7.0, preferably with respect to Li B / Ti B The ratio is in the range of 2.5 to 6.0, and more preferably, specific Li B / Ti B This includes single particles and / or secondary particles, where the coefficient is in the range of 3.0 to 5.0.

[0104] A particular preferred embodiment is the positive electrode active material of the present invention, Including single particles and / or secondary particles, The carbon content is in the range of 0.020% to 0.50% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.050% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Li A The ratio is in the range of 2.0 to 8.0, preferably with respect to Li B / Li A The ratio is in the range of 2.5 to 7.0, and more preferably, specific Li B / Li A This relates to positive electrode active materials where the value is in the range of 3.0 to 6.0.

[0105] A particular preferred embodiment is the positive electrode active material of the present invention, Including single particles and / or secondary particles, The carbon content is in the range of 0.020% to 0.50% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.050% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Ti B The ratio is in the range of 2.0 to 7.0, preferably with respect to Li B / Ti B The ratio is in the range of 2.5 to 6.0, and more preferably, specific Li B / Ti B This relates to positive electrode active materials where the value is in the range of 3.0 to 5.0.

[0106] A particular preferred embodiment is a positive electrode active material, Including single particles and / or secondary particles, The carbon content is in the range of 0.020% to 0.50% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.025% to 0.040% by weight, and more preferably in the range of 0.030% to 0.050% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Li A The ratio is in the range of 2.0 to 8.0, preferably with respect to LiB / Li A The ratio is in the range of 2.5 to 7.0, and more preferably, specific Li B / Li A The range is 3.0 to 6.0. Filipino Li B / Ti B The ratio is in the range of 2.0 to 7.0, preferably with respect to Li B / Ti B The ratio is in the range of 2.5 to 6.0, and more preferably, specific Li B / Ti B This relates to positive electrode active materials where the value is in the range of 3.0 to 5.0.

[0107] A particular preferred embodiment is a positive electrode active material, Including single particles and / or secondary particles, The Co content of the particles was measured at the edges of the particles by cross-sectional EDS (CS-EDS). edge Co edge However, this is expressed as mol% of the total Ni, Mn, and Co content measured by CS-EDS at the edges of the particle, and the Co content measured by CS-EDS at the center of the particle. center Co center However, it is expressed as mol% relative to the total Ni, Mn, and Co content measured by CS-EDS at the center of the particle, and specific Co edge / Co center >1.10, preferably Co edge / Co center >1.20, more preferably Co edge / Co center >1.30, most preferably Co edge / Co center Regarding the positive electrode active material, the value is >1.50.

[0108] In the framework of this invention, the edges of a particle are boundaries or external limits that distinguish the particle from its external environment. The center of a particle is the midpoint of the longest straight line connecting the two points at the edges of the particle.

[0109] A particular preferred embodiment is a positive electrode active material, Including single particles and / or secondary particles, Particles,

[0110]

number

[0111] Al content is defined as [wherein c is the Al content measured by XPS] A The positive electrode active material has an Al content determined by XPS analysis. B It has Al B This is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Al measured by XPS analysis, and the specific Al B / Al A >1.0, preferably relative to Al B / Al A >2.0, more preferably relative to Al B / Al A >2.5, more preferably relative to Al B / Al A >3.0, more preferably relative to Al B / Al A >3.5, most preferably relative to Al B / Al A Regarding the positive electrode active material, which is >4.0.

[0112] A particular preferred embodiment is a positive electrode active material, Including single particles and / or secondary particles, The Co content of the particles was measured at the edges of the particles by cross-sectional EDS (CS-EDS). edge Co edge However, this is expressed as mol% of the total Ni, Mn, and Co content measured by CS-EDS at the edges of the particle, and the Co content measured by CS-EDS at the center of the particle. center Co center However, it is expressed as mol% relative to the total Ni, Mn, and Co content measured by CS-EDS at the center of the particle, and specific Co edge / Cocenter >1.10, preferably Co edge / Co center >1.20, more preferably Co edge / Co center >1.30, most preferably Co edge / Co center >1.50, Particles,

[0113]

number

[0114] Al content is defined as [wherein c is the Al content measured by XPS] A The positive electrode active material has an Al content determined by XPS analysis. B It has Al B This is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Al measured by XPS analysis, and the specific Al B / Al A >1.0, preferably relative to Al B / Al A >2.0, more preferably relative to Al B / Al A >2.5, more preferably relative to Al B / Al A >3.0, more preferably relative to Al B / Al A >3.5, most preferably relative to Al B / Al A Regarding the positive electrode active material, which is >4.0.

[0115] In certain preferred embodiments, the cathode active material of the present invention comprises polycrystalline particles. As those skilled in the art will understand, in polycrystalline particles, five or more single-crystal particles, preferably ten or more single-crystal particles, and more preferably fifty or more single-crystal particles are aggregated. This can be observed by observing the grain boundaries with a suitable microscopy technique such as a scanning electron microscope (SEM). The aggregation of single-crystal particles into polycrystalline particles occurs under post-treatment steps such as a heat treatment step.

[0116] In certain preferred embodiments, the polycrystalline particles aggregate more than 20 primary particles, preferably 50 or more primary particles, and more preferably 100 or more primary particles. Therefore, in certain preferred embodiments, the positive electrode active material is a powder containing polycrystalline particles, each of which consists of more than 20 primary particles, preferably 50 or more primary particles, and more preferably 100 or more primary particles, as observed in SEM images.

[0117] Preferably, at least 30%, more preferably at least 50%, of the particles constituting the powder observed in the SEM image are polycrystalline particles. The number of primary particles constituting the polycrystalline particles is at least 45 μm × at least 60 μm (i.e., at least 2700 μm). 2 ), preferably at least 100 μm × 100 μm (i.e., at least 10,000 μm) 2 This is required within the field of view of the SEM. The particles in the image must be properly dispersed, and thus overlap between particles must be avoided. This can be achieved by applying a small amount of powder sample to the adhesive attached to the SEM sample holder and blowing air to remove excess powder.

[0118] In a particular preferred embodiment, the positive electrode active material of the present invention comprises polycrystalline particles having a carbon content of more than 0.035% by weight, preferably more than 0.040% by weight, and more preferably more than 0.045% by weight, relative to the total weight of the positive electrode active material. In a particular preferred embodiment of the present invention, the positive electrode active material of the present invention comprises polycrystalline particles having a carbon content of less than 0.075% by weight, preferably less than 0.070% by weight, and more preferably less than 0.065% by weight, relative to the total weight of the positive electrode active material. In a particular preferred embodiment of the present invention, the positive electrode active material comprises polycrystalline particles having a carbon content in the range of 0.035% to 0.075% by weight, preferably in the range of 0.040% to 0.070% by weight, and more preferably in the range of 0.045% to 0.065% by weight, relative to the total weight of the positive electrode active material.

[0119] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Li A >3.0, preferably specific Li B / Li A >3.5, more preferably relative Li B / Li A It contains polycrystalline particles with a specific Li ratio of >4.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio of >4.0. B / Li A <10.0, preferably relative Li B / Li A <9.0, Lithium-ion of the light source B / Li A It contains polycrystalline particles with a specific Li ratio <8.5. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio B / Li A The ratio is in the range of 3.0 to 10.0, preferably with respect to Li B / Li A The ratio is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A It includes polycrystalline particles, where the coefficient is in the range of 4.0 to 8.5.

[0120] In certain preferred embodiments, the positive electrode active material of the present invention is specific Li B / Ti B >4.0, preferably relative Li B / Ti B >5.0, more comfortably compared to Li B / Ti B It contains polycrystalline particles with a specific Li ratio of >6.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Ti B <12.0, preferably relative Li B / Ti B <11.0, Lithium-ion ratio B / Ti B It contains polycrystalline particles with a specific Li ratio of <10.0. In certain preferred embodiments, the positive electrode active material of the present invention has a specific Li ratio. B / Ti B The ratio is in the range of 4.0 to 12.0, preferably with respect to Li B / Ti B The ratio is in the range of 5.0 to 11.0, and more preferably, the ratio Li B / Ti B It includes polycrystalline grains in the range of 6.0 to 10.0.

[0121] A particular preferred embodiment is the positive electrode active material of the present invention, Contains polycrystalline particles, The carbon content is in the range of 0.035% to 0.075% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.040% to 0.070% by weight, and more preferably in the range of 0.045% to 0.065% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Li A The ratio is in the range of 3.0 to 10.0, preferably with respect to Li B / Li A The ratio is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A This relates to positive electrode active materials, where the value is in the range of 4.0 to 8.5.

[0122] A particular preferred embodiment is the positive electrode active material of the present invention, Contains polycrystalline particles, The carbon content is in the range of 0.035% to 0.075% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.040% to 0.070% by weight, and more preferably in the range of 0.045% to 0.065% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Ti B The ratio is in the range of 4.0 to 12.0, preferably with respect to Li B / Ti B The ratio is in the range of 5.0 to 11.0, and more preferably, the ratio Li B / Ti B This relates to positive electrode active materials where the value is in the range of 6.0 to 10.0.

[0123] A particular preferred embodiment is the positive electrode active material of the present invention, Contains polycrystalline particles, The carbon content is in the range of 0.035% to 0.075% by weight relative to the total weight of the positive electrode active material, preferably in the range of 0.040% to 0.070% by weight, and more preferably in the range of 0.045% to 0.065% by weight relative to the total weight of the positive electrode active material. Filipino Li B / Li A The ratio is in the range of 3.0 to 10.0, preferably with respect to Li B / Li A The ratio is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A The range is 4.0 to 8.5. Filipino Li B / Ti B The ratio is in the range of 4.0 to 12.0, preferably with respect to Li B / Ti B The ratio is in the range of 5.0 to 11.0, and more preferably, the ratio Li B / Ti B This relates to positive electrode active materials where the value is in the range of 6.0 to 10.0.

[0124] Specific preferred embodiments relate to the cathode active material of the present invention comprising single crystal particles having a primary particle median D50 value of less than 10 μm, preferably less than 8 μm, and more preferably less than 5 μm. Specific preferred embodiments relate to the cathode active material of the present invention comprising single crystal particles having a primary particle median D50 value of greater than 1 μm, preferably greater than 2 μm, and more preferably greater than 3 μm. Specific preferred embodiments relate to the cathode active material of the present invention comprising single crystal particles having a primary particle median D50 value of 1 to 10 μm, preferably 2 to 8 μm, and more preferably 3 to 5 μm. As those skilled in the art will understand, the particle size distribution (PSD) D50 of the cathode active material powder is measured by laser diffraction particle size analysis. For example, although not limited to the present invention, the particle median D50 can be measured using a Malvern Mastersizer 3000.

[0125] Specific preferred embodiments relate to the positive electrode active material of the present invention comprising single particles and / or secondary particles having a particle median D50 value of less than 10 μm, preferably less than 8 μm, and more preferably less than 5 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention comprising single particles and / or secondary particles having a particle median D50 value of greater than 1 μm, preferably greater than 2 μm, and more preferably greater than 3 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention comprising single particles and / or secondary particles having a particle median D50 value of 1 to 10 μm, preferably 2 to 8 μm, and more preferably 3 to 5 μm. As those skilled in the art will understand, the particle size distribution (PSD) D50 of the positive electrode active material powder is measured by laser diffraction particle size analysis. For example, although not limited to the present invention, the particle median D50 can be measured using a Malvern Mastersizer 3000. Preferably, the particle median D50 is the volume median particle size.

[0126] A particular preferred embodiment relates to the cathode active material of the present invention comprising polycrystalline particles having a secondary particle median D50 value of less than 10 μm, preferably less than 8 μm, and more preferably less than 5 μm. A particular preferred embodiment relates to the cathode active material of the present invention comprising polycrystalline particles having a secondary particle median D50 value of greater than 1 μm, preferably greater than 2 μm, and more preferably greater than 3 μm. A particular preferred embodiment relates to the cathode active material of the present invention comprising polycrystalline particles having a secondary particle median D50 value of 1 to 10 μm, preferably 2 to 8 μm, and more preferably 3 to 5 μm. As those skilled in the art will understand, the particle size distribution (PSD) D50 of the cathode active material powder is measured by laser diffraction particle size analysis. For example, although not limited to the present invention, the particle median D50 can be measured using a Malvern Mastersizer 3000. Preferably, the particle median D50 is the volume median particle size.

[0127] method In a second embodiment, the present invention relates to a method for producing a positive electrode active material, The process involves preparing a slurry of a lithium transition metal oxide compound, a first lithium source, water, and an alcohol. The slurry is mixed with a Ti source, The present invention provides a method for obtaining a positive electrode active material by heating a mixture at a temperature of 250°C or higher but less than 500°C for a period of 1 to 20 hours.

[0128] In a very preferred embodiment of the method for producing a positive electrode active material of the present invention, the positive electrode active material is according to a first aspect of the present invention. As those skilled in the art will understand, when the method for producing a positive electrode active material of the present invention provides a positive electrode material according to a first aspect of the present invention, all embodiments relating to the positive electrode active material according to a first aspect of the present invention apply mutatis mutandis to the method for producing a positive electrode active material according to a first aspect of the present invention. For example, Li, M', Ti described herein in the context of positive electrode active materials. A Ti B Li A and Li BVarious embodiments relating to the identity and quantity are equally applicable to methods for preparing the positive electrode active material.

[0129] In a preferred embodiment of this method, the lithium transition metal oxide compound comprises Li, M', and oxygen, where M' comprises Ni, Mn, Co, and D, and D is Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably at least one element selected from the group consisting of B, Nb, Zr, and W. Preferably, the lithium transition metal oxide used is also prepared by a lithiation process, which is a process of heating a mixture of a transition metal oxide precursor and a second lithium source at a temperature preferably at least 500°C and at most 1000°C. Typically, the transition metal precursor is prepared by coprecipitation of one or more transition metal sources, such as salts, preferably sulfates or nitrates, more preferably sulfates, with the elements Ni, Mn, and / or Co in the presence of an alkali compound, such as an alkali hydroxide, such as sodium hydroxide and / or ammonia. Preferably, the second lithium source is metallic lithium or a lithium salt, preferably a lithium salt such as LiOH. Optionally, the lithium transition metal oxide compound comprises single crystal particles or single particles and / or secondary particles, as described herein, and is further mixed with a Co source such as Co3O4 and a third lithium source, preferably the third lithium source is metallic lithium or a lithium salt, preferably a lithium salt such as LiOH, the Co source has a Co content in the range of 1.0 to 2.0 mol% relative to the total of Ni, Mn, and Co, and the Li source has a Li content in the range of 5.0 to 10 mol% relative to the total of Ni, Mn, and Co. Optionally, the lithium transition metal oxide compound is further pulverized and sieved with alumina in an amount of 250 to 750 ppm relative to the total amount of positive electrode active material.

[0130] In a preferred embodiment of this method, the first Li source is metallic lithium or a lithium salt, preferably a lithium salt such as LiOH.

[0131] In a preferred embodiment, the slurry has a solid content of more than 40% by weight (relative to the total weight of the slurry), preferably more than 50% by weight, and more preferably more than 55% by weight (relative to the total weight of the slurry). In a preferred embodiment, the slurry has a solid content of less than 80% by weight (relative to the total weight of the slurry), preferably less than 70% by weight, and more preferably less than 65% by weight (relative to the total weight of the slurry). In a preferred embodiment, the slurry has a solid content in the range of 40% to 80% by weight (relative to the total weight of the slurry), preferably in the range of 50% to 70% by weight, and more preferably in the range of 55% to 65% by weight (relative to the total weight of the slurry).

[0132] In a preferred embodiment of this method, the alcohol is methanol, ethanol, propanol, butanol, or a combination thereof, and is preferably ethanol.

[0133] In a preferred embodiment of this method, the molar ratio of Li present in the first Li source to Ti present in the Ti source is in the range of 5:1 to 1:3, preferably in the range of 4:1 to 1:2, more preferably in the range of 3:1 to 1:1, for example, about 2:1.

[0134] In a preferred embodiment of this method, the molar ratio of water to Ti present in the Ti source is in the range of 5:1 to 1:3, preferably in the range of 4:1 to 1:2, more preferably in the range of 3:1 to 1:1, for example, about 2:1.

[0135] In a preferred embodiment of this method, the molar ratio of water to Li present in the first Li source is in the range of 4:1 to 1:4, preferably in the range of 3:1 to 1:3, more preferably in the range of 2:1 to 1:2, for example, about 1:1.

[0136] In a preferred embodiment, the amount of water in the slurry is 0.5 mol% to 25.0 mol%, preferably 0.7 mol% to 10.0 mol%, and more preferably 1 mol% to 5 mol%, relative to the metal content in the lithium transition metal oxide compound.

[0137] In a preferred embodiment, the amount of Li present in the first lithium source in the slurry is 0.5 mol% to 25.0 mol% relative to the metal content in the lithium transition metal oxide compound, preferably 0.7 mol% to 10.0 mol%, and more preferably 1.0 mol% to 5.0 mol% relative to the metal content in the lithium transition metal oxide compound.

[0138] In a preferred embodiment, the amount of Ti present in the titanium source in the slurry is 0.1 mol% to 10.0 mol%, preferably 0.25 mol% to 5.0 mol%, and more preferably 0.5 mol% to 1.5 mol%, relative to the metal content in the lithium transition metal oxide compound. In a preferred embodiment, the Ti source is a Ti alkoxide, preferably a Ti ethoxide, Ti propoxide, or Ti butoxide, more preferably a Ti propoxide or Ti isopropoxide, such as Ti(IV) propoxide or Ti(IV) isopropoxide. In a preferred embodiment, the Ti alkoxide is mixed with the mixture as a solid. Alternatively, the Ti alkoxide is mixed with the slurry as a solution, the solution containing the Ti alkoxide and a further alcohol, where the alkoxide group is a conjugate base of the further alcohol. For example, the Ti alkoxide is Ti(IV) propoxide dissolved in propanol. Typically, the solution contains 50 to 90% by weight of Ti alkoxide relative to the total weight of the solution. Examples of such solutions include 70% by weight of Ti(IV) isopropoxide in 1-propanol, or 80% by weight of Ti(IV) butoxide in 1-butanol.

[0139] A preferred embodiment of this method is to mix the mixture At a temperature of 275°C to 450°C, preferably 300°C to 400°C, more preferably 325°C to 375°C, The heating is to last for 2 to 15 hours, preferably 3 to 10 hours, and more preferably 4 to 7 hours.

[0140] A preferred embodiment of this method is heating the mixture under an oxidizing atmosphere. Preferably, the oxidizing atmosphere contains oxygen, such as air, or consists of oxygen.

[0141] In a more preferred embodiment, heating is performed inside a furnace.

[0142] In certain preferred embodiments, the method includes a further step of filtering and drying the mixture before heating it. Preferably, the drying is carried out under vacuum, under vacuum heating, or under a constant flow of N2 gas for at least 4 hours and a maximum of 20 hours. As those skilled in the art will understand, the filtration of the mixture is achieved by conventional filtration techniques known in the art.

[0143] In certain preferred embodiments, the method includes a further step of drying the mixture before heating it. Preferably, the drying is carried out under vacuum, under vacuum heating, or under a constant flow of N2 gas for at least 4 hours and a maximum of 20 hours.

[0144] Product-by-process In a third embodiment, the present invention relates to a positive electrode active material obtained by a method according to a second aspect of the present invention.

[0145] As those skilled in the art will understand, all embodiments of the positive electrode active material according to the first aspect of the present invention and / or the method according to the second aspect of the present invention are applicable mutatis mutandis to positive electrode active materials obtained by the method according to the present invention. For example, Li, M', Ti described herein in the context of positive electrode active materials. A Ti B Li A and Li BVarious embodiments relating to the identity and quantity are equally applicable to positive electrode active materials obtained by methods for preparing positive electrode active materials.

[0146] battery In a fourth embodiment, the present invention relates to a battery comprising a positive electrode active material according to a first aspect of the present invention and / or a positive electrode active material obtained by a method according to a third aspect of the present invention.

[0147] In a preferred embodiment, the battery is a solid-state battery. Preferably, the solid-state battery contains a sulfide-based electrolyte. Preferably, the electrolyte is a sulfide-based solid electrolyte, and more preferably, the electrolyte contains Li, P, and S. Typically, the following sulfur-containing compounds are used: Li6PS5Cl(LPSCL), thio-LISICON(Li 3.25 Ge 0.25 P 0.75 S4), Li2S-P2S5-LiCl, Li2S-SiS2, LiI-Li2S-SiS2, Li2S-P2S5-LiCl, Li2S-SiS2, LiI-Li 2S-SiS2, LiI-Li2S-P2S5, LiI-Li2SP2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S 11 , LiI-Li2S-B2S3, Li3PO4-Li2S-SiS2, Li3PO4-Li2S-SiS2, Li3PO4-Li2S-SiS2, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 , and / or Li7P3S 11 This can be suitably used. In a very preferred embodiment, the battery is a sulfide solid battery.

[0148] Preferably, the solid-state battery further comprises an anode containing an anode active material. Suitable electrochemically active anode materials are known in the art. For example, the anode may contain graphite carbon, metallic lithium, or a lithium-containing metallic alloy such as a Li-In alloy as the anode active material.

[0149] In a preferred embodiment, the battery according to the present invention has an efficiency of at least 88%, preferably at least 90%, more preferably at least 92%, and most preferably at least 94%. As those skilled in the art will understand, the efficiency of the battery is required as described in item E2) of the Examples.

[0150] In a preferred embodiment, the battery according to the present invention has an initial discharge capacity of at least 200 mAh / g, more preferably at least 205 mAh / g, and most preferably at least 210 mAh / g. As those skilled in the art will understand, the initial discharge capacity (DQ1) is measured in constant current mode (CC) with a C rate of 0.1C and a voltage range of 4.3V to 2.5V (Li / Li + ) or 3.7V~1.9V (InLi / Li + It is measured at ).

[0151] use In a fifth embodiment, the present invention relates to the use of a positive electrode active material obtained by a method according to a first aspect of the present invention and / or a positive electrode active material obtained by a method according to a third aspect of the present invention.

[0152] A preferred embodiment is the use of a positive electrode active material to improve the efficiency of a battery, preferably a solid-state battery, more preferably a sulfide solid-state battery, and / or to increase the initial discharge capacity of the battery.

[0153] In a sixth embodiment, the present invention relates to the use of a battery according to the present invention in any one of a portable computer, a tablet, a mobile phone, an energy storage system, or an electric vehicle, or in a hybrid electric vehicle, preferably in an electric vehicle or a hybrid electric vehicle. [Examples]

[0154] Experimental tests used in the examples In this embodiment, the following analysis method is used.

[0155] A) ICP analysis The amounts of Li, Ni, Mn, Co, and Ti in the positive electrode active material powder are measured by inductively coupled plasma (ICP-OES) using an Agilent ICP 720-ES. 2 grams of the powder sample are dissolved in 10 mL of high-purity hydrochloric acid (at least 37% by weight of HCl relative to the total weight of the solution) in an Erlenmeyer flask. The flask is covered with glass and heated on a 380°C hot plate until the powder is completely dissolved. After cooling to room temperature, the solution from the Erlenmeyer flask is poured into a 250 mL volumetric flask. The volumetric flask is then filled to the 250 mL mark with deionized water and then homogenized. An appropriate amount of solution is pipettered and transferred to a 250 mL volumetric flask for a second dilution. The volumetric flask is then filled to the 250 mL mark with an internal standard and 10% hydrochloric acid and then homogenized. Finally, this 50 mL solution is used for ICP-OES measurement.

[0156] B) Particle size The particle size distribution (PSD) of the positive electrode active material powder is measured by laser diffraction particle size analysis using a Malvern Mastersizer 3000 equipped with a Hydro MV wet dispersion attachment after each powder sample is dispersed in an aqueous medium. To improve powder dispersion, sufficient ultrasonic irradiation and stirring are applied, and an appropriate surfactant is introduced. D50 is defined as the particle size at 50% of the cumulative volume % distribution obtained from the Malvern Mastersizer 3000 based on Hydro MV measurements.

[0157] C) X-ray photoelectron spectroscopy In this invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of cathode active material powder particles. In XPS measurements, the signal is acquired from the top of the sample, i.e., the first few nanometers (e.g., 1 nm to 10 nm) of the surface layer. Therefore, all elements measured by XPS are contained in the surface layer.

[0158] For surface analysis of cathode active material powder particles, XPS measurements are performed using a ThermoK-α+ spectrometer (Thermo Scientific). Single-wavelength Al Kα radiation (hυ = 1486.6 eV) is used with a spot size of 400 μm and a measurement angle of 45°. A broad survey scan to identify elements present on the surface is performed at a pass energy of 200 eV. The C1s peak with maximum intensity (or center) at a binding energy of 284.8 eV is used as the calibration peak position after data acquisition. Subsequently, for each identified element, at least 10 precise narrow scans are performed at 50 eV to determine the accurate surface composition.

[0159] Curve fitting is performed using CasaXPS version 2.3.19PR1.0 (Casa Software) with Shirley-type background processing and Scofield sensitivity coefficients. The fitting parameters are as shown in Table 1a. The linear shape GL(30) is a Gauss / Lorentz product equation containing 70% Gaussian lines and 30% Lorentz lines.

[0160] [Table 1]

[0161] For the Ti and Co peaks, restrictions are set for the peaks identified in Table 1b.

[0162] [Table 2]

[0163] The Ti and Li surface content determined by XPS is expressed as the mole fraction of Ti and Li in the surface layer of the particle divided by the total content of Ni, Mn, Co, and Ti in that surface layer. This is calculated as follows:

[0164]

number

[0165] D) Carbon analyzer The carbon content of the positive electrode active material powder is measured using a Horiba Emia-Expert carbon / sulfur analyzer. 1 g of positive electrode active material powder is placed in a ceramic crucible in a high-frequency induction electric furnace. 1.5 g of tungsten and 0.3 g of tin are added to the crucible as accelerators. The powder is heated at a programmable temperature, and the gas subsequently produced during combustion is analyzed using an infrared detector. The carbon concentration is determined by the analysis of CO2 and CO.

[0166] E) Sulfide Solid Battery Test E1) Preparation of sulfide solid-state batteries Preparation of the positive electrode: To prepare the positive electrode, a slurry containing positive electrode active material powder, Li-PS-Cl solid electrolyte, carbon (Super-P, Timcal), and binder (RC-10, Arkema) in a weight ratio of 64.0:30.0:3.0:3.0 is mixed in butyl acetate solvent in an Ar-filled glove box. The slurry is cast onto one side of aluminum foil, and the slurry-coated foil is then dried in a vacuum oven to obtain the positive electrode. The obtained positive electrode is punched out to a diameter of 10 nm, with an active material load of approximately 4 mg / cm³. 2 That is the case.

[0167] Preparation of the negative electrode: To prepare the negative electrode, a Li foil (3 mm in diameter, 100 μm thick) is placed in the center of an In foil (10 nm in diameter, 100 μm thick), and pressed to form a Li-In alloy negative electrode.

[0168] Separator To prepare a separator that also functions as a solid electrolyte in a battery, a Li-PS-Cl solid electrolyte is pelletized at a pressure of 250 MPa to obtain a pellet thickness of 1 mm.

[0169] Cell assembly The sulfide solid cell is assembled in an argon-filled glove box from bottom to top in the following order: positive electrode with an Al current collector having a coated portion on top - separator - negative electrode with the Li side facing up - Cu current collector. The stacked components are pressed together under a pressure of 250 MPa and placed in an external cage to prevent exposure to air.

[0170] E2) Test Method The test method is the conventional "constant cutoff voltage" test. The conventional cell test in this invention follows the schedule shown in Table 2. Each cell is cycled at 60°C using a Toscat-3100 computer-controlled galvanostatic cycling station (manufactured by Toyo).

[0171] This schedule uses a 1C current definition of 160mA / g. The initial charge capacity (CQ1) and discharge capacity (DQ1) are 4.3V~2.5V (Li / Li + ) or 3.7V~1.9V (InLi / Li + ) is measured in constant current mode (CC) at a C rate of 0.1C within the voltage range.

[0172] Efficiency EF is expressed as a percentage, as follows:

[0173]

number

[0174] [Table 3]

[0175] The present invention is further illustrated in the following embodiments.

[0176] Comparative Example 1 A monolithic cathode active material labeled CEX1.1 (i.e., a cathode active material containing single and secondary particles) was prepared according to the following steps: Step 1) Preparation of transition metal hydroxide precursor: Metal composition Ni 0.85 Mn 0.07 Co 0.08 Nickel-based transition metal hydroxide powder (TMH1) containing the following was prepared by coprecipitation in a large-scale continuous stirred tank reactor (CSTR) containing a mixture of nickel manganese cobalt sulfate, sodium hydroxide, and ammonia.

[0177] Step 2) First mixing: The TMH1 prepared from Step 1) was mixed with LiOH in an industrial blender to obtain a first mixture with a lithium-to-metal M' (Li / M') ratio of 0.96.

[0178] Step 3) First heating: The first mixture from Step 2) was heated at 885°C for 11 hours under an oxidizing atmosphere to obtain the first heating product.

[0179] Step 4) Wet bead milling: The first heating product from Step 3) was bead milled in a solution containing 0.5 mol% Co relative to the total molar content of Ni, Mn, and Co in the first heating product, followed by drying and sieving to obtain the milled product. The weight ratio of solid to solution for bead milling was 6:4 and the process was carried out for 40 minutes.

[0180] Step 5) Drying: The milled product obtained from Step 4) was dried at 150°C for 12 hours.

[0181] Step 6) Second mixing: The dried product obtained from Step 5) was mixed in an industrial blender with 1.5 mol% of CO3O4-derived Co and 7.5 mol% of LiOH-derived Li, respectively, relative to the total molar content of Ni, Mn, and Co in the milled product, to obtain a second mixture.

[0182] Step 7) Second heating: The second mixture from Step 6) was heated at 760°C for 10 hours under an oxidizing atmosphere, then ground, and 500 ppm alumina powder was added and sieved to obtain CEX1.1.

[0183] CEX1.2 is prepared by mixing CEX1.1 with 0.45 mol% Ti from TiO2 and 0.90 mol% Li from LiOH, followed by heating at 350°C for 6 hours under an oxidizing atmosphere.

[0184] Example 1 A monolithic cathode active material labeled EX1.1 (i.e., a cathode active material containing single and secondary particles) was prepared according to the following steps: Step 1) Preparation of Ti solution: 0.97 mol% Ti from Ti isopropoxide was dissolved in 4 grams of ethanol.

[0185] Step 2) Slurry preparation: 60 grams of CEX1.1 was mixed with 1.94 mol% LiOH and 1.94 mol% water relative to both Ti and 40 grams of ethanol to form a slurry.

[0186] Step 3) Mixing: The Ti solution prepared in Step 1) and the slurry prepared in Step 2) were mixed and stirred at room temperature for 15 hours, then filtered and dried in vacuum at 80°C for 6 hours.

[0187] Step 4) Heating: The dried powder from Step 3) was heated at 350°C for 5 hours under an oxygen atmosphere and obtained by ICP-OES, yielding EX1.1 having M' containing Ni, Mn, Co, and Ti in a Ni:Mn:Co:Ti ratio of 0.84:0.07:0.09:0.010. EX1.1 has a D50 of 4 μm.

[0188] EX1.2 was prepared according to the same method as EX1.1, except that 0.58 mol% Ti from Ti isopropoxide was used in step 1), and 1.16 mol% Li and 1.97 mol% H2O from LiOH were used in step 2).

[0189] EX1.3 was prepared according to the same method as EX1.1, except that 0.38 mol% Ti from Ti isopropoxide was used in step 1), and 0.76 mol% Li and 1.90 mol% H2O from LiOH were used in step 2).

[0190] Comparative Example 2 A polycrystalline cathode active material labeled CEX2 was prepared according to the following steps.

[0191] Step 1) Preparation of transition metal hydroxide precursor: Metal composition Ni 0.83 Mn 0.12 Co 0.05 Nickel-based transition metal hydroxide powder (TMH2) containing the following was prepared by coprecipitation in a large-scale continuous stirred tank reactor (CSTR) containing a mixture of nickel-manganese-cobalt sulfate, sodium hydroxide, and ammonia.

[0192] Step 2) First mixing: The TMH2 prepared from Step 1) was mixed with LiOH in an industrial blender to obtain a first mixture with a lithium-to-metal M' (Li / M') ratio of 0.97.

[0193] Step 3) First heating: The first mixture from Step 2) was heated at 750°C for 11 hours under an oxidizing atmosphere to obtain the first heating product.

[0194] Step 4) Second mixing: The first heating product was mixed with LiOH in an industrial blender to obtain the first mixture with a lithium-to-metal M' (Li / M') ratio of 1.02.

[0195] Step 5) Second heating: The second mixture from Step 4) was heated at 770°C for 12 hours under an oxidizing atmosphere, then ground and sieved to obtain CEX2.

[0196] Example 2 A polycrystalline cathode active material labeled EX2.1 was prepared according to the following steps.

[0197] Step 1) Preparation of Ti solution: 0.63 mol% Ti from Ti isopropoxide was dissolved in 4 grams of ethanol.

[0198] Step 2) Slurry preparation: 60 grams of CEX1.1 was mixed with 1.26 mol% LiOH and 1.26 mol% water relative to both M' and 40 grams of ethanol to form a slurry.

[0199] Step 3) Mixing: The Ti solution prepared in Step 1) and the slurry prepared in Step 2) were mixed and stirred at room temperature for 15 hours, then filtered and dried in vacuum at 80°C for 6 hours.

[0200] Step 4) Heating: The dried powder from Step 3) was heated at 350°C for 5 hours under an oxygen atmosphere, and when obtained by ICP-OES, EX2.1 was obtained having M' containing Ni, Mn, Co, and Ti in a Ni:Mn:Co:Ti ratio of 0.83:0.12:0.05:0.006. EX2.1 has a D50 of 5.5 μm.

[0201] EX2.2 was prepared according to the same method as EX2.1, except that 0.38 mol% Ti from Ti isopropoxide was used in step 1), and 0.76 mol% Li and 0.76 mol% H2O from LiOH were used in step 2).

[0202] EX2.3 was prepared in the same manner as EX2.2, except that the mixture was dried using a vacuum pump in step 3).

[0203] result

[0204] [Table 4]

[0205] *Based on the molar content of Ni, Mn, Co, and Ti **na = Not applicable** Table 3 summarizes the compositions of the examples and comparative examples, and their corresponding electrochemical properties. The results of the XPS analysis show Ti B and Li B The table shows the atomic ratios (equivalent to molar ratios) of Li and Ti relative to the total atomic fractions of Ni, Mn, Co, and Ti. The table also compares the results with those of ICP. An atomic ratio greater than 1 indicates that the above-mentioned Li and Ti are enriched on the surface of the cathode active material, in relation to XPS measurements where the signal is acquired from the top few nanometers (e.g., 1 nm to 10 nm) of the sample, i.e., the surface layer. On the other hand, the atomic ratios of Li and Ti obtained from ICP measurements are obtained from the entire particle. Therefore, an XPS to ICP ratio greater than 1 indicates that the elements Li and Ti are mainly present on the surface of the cathode active material.

[0206] CEX1.1, CEX1.2, and EX1.1-EX1.3 are monolithic cathode active materials with a Ni content of 84 mol%. CEX1.1 is the core material, while CEX1.2 is obtained by dry mixing CEX1.1 with a Ti material and then heating it. Due to differences in the process of introducing Ti by preparing a Ti solution, EX1.1-EX1.3 have a higher Ti content compared to CEX1.2. B and Ti B / Ti A The ratio is increasing. Furthermore, there is a correlation between the higher the surface Ti content and the improved efficiency of the solid-state battery.

[0207] CEX2 and EX2.1-EX2.3 are polycrystalline cathode active materials with a Ni content of 83 mol%. EX2.1 and EX2.2, prepared according to the method of the present invention, have a higher Ti content compared to CEX2. B , and Ti B / Ti A This ratio indicates higher electrochemical cell efficiency. EX2.3 was prepared according to the same method as EX2.2, except that filtration was replaced with evaporation. Both EX2.2 and EX2.3, having the same Ti content, exhibit similar electrochemical cell efficiency.

[0208] In this invention, comparisons between CEX1 and EX1, and between CEX2 and EX2 are illustrated. All of these samples have higher Ti than each comparative example. B This indicates an improvement in electrochemical cell efficiency in relation to the ratio.

Claims

1. A positive electrode active material for a solid-state battery, wherein the positive electrode active material contains Li, M' and oxygen, and M' is Ni content x such that 55.0 mol% ≤ x ≤ 98.0 mol%, The Mn content y is such that 0.0 mol% ≤ y ≤ 45.0 mol%, Co with a content z such that 0.0 mol% ≤ z ≤ 45.0 mol%, A D having a content a such that 0.0 mol% ≤ a ≤ 5.0 mol%, and D being at least one element other than Li, Ni, Mn, Co, Ti, and O, The Ti content is 0.01 mol% ≤ b ≤ 5.0 mol%, and the substance contains Ti with a content of b. x, y, z, a, and b are measured by ICP-OES. x + y + z + a + b is 100.0 mol%, The positive electrode active material is [Math 1] Ti content defined as Ａ It has, The Ti content of the aforementioned positive electrode active material is determined by XPS analysis. Ｂ It has Ti Ｂ However, this is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti measured by XPS analysis. ratio Ti Ｂ / Ti Ａ > 25.0, The positive electrode active material has a Li content determined by ICP analysis. Ａ It has Li Ａ However, this is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti measured by ICP analysis. where the positive electrode active material has a Li content Li determined by XPS analysis Ｂ and Li Ｂ is expressed as a molar fraction compared with the total molar fractions of Co, Mn, Ni, and Ti measured by XPS analysis Ratio Li Ｂ / Li Ａ The positive electrode active material is >1.

0.

2. The positive electrode active material according to claim 1, wherein D is at least one element selected from the group consisting of Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, V, W, Y, Zn, and Zr.

3. Ratio Li Ｂ / Li Ａ The positive electrode active material according to claim 2, wherein the coefficient is >2.

0.

4. Ratio Li Ｂ / Ti Ｂ The positive electrode active material according to claim 1, wherein the coefficient is >2.

0.

5. Ratio Li Ｂ / Ti Ｂ The positive electrode active material according to claim 1, wherein the value is <60.

0.

6. ratio Ti Ｂ / Ti Ａ The positive electrode active material according to claim 1, wherein the coefficient is >50.

0.

7. The positive electrode active material according to claim 1, wherein 60.0 mol% ≤ x ≤ 95.0 mol%.

8. The positive electrode active material according to claim 1, wherein 0.05 mol% ≤ b ≤ 2.5 mol%.

9. A method for producing a positive electrode active material according to any one of claims 1 to 8, The process involves preparing a slurry of a lithium transition metal oxide compound, a first lithium source, water, and an alcohol. The slurry is mixed with a Ti source, A method comprising: heating a mixture at a temperature of 250°C or higher and less than 500°C for 1 to 20 hours to obtain the positive electrode active material.

10. The method according to claim 9, further comprising the step of filtering and drying the mixture before heating it.

11. The method according to claim 9, further comprising the step of drying the mixture before heating it.

12. The method according to claim 9, wherein the Ti source is Ti propoxide or Ti isopropoxide.

13. The method according to claim 9, wherein the amount of water in the slurry is 0.5 mol% to 25.0 mol% relative to the metal content in the lithium transition metal oxide compound.

14. The method according to claim 9, wherein the pH of the slurry is > 7.

15. A solid-state battery comprising a positive electrode active material according to any one of claims 1 to 8.

16. The solid battery according to claim 15, comprising a sulfide-based solid electrolyte containing Li, P, and S.

17. Use of the solid battery according to claim 15 in any one of a portable computer, tablet, mobile phone, energy storage system, electric vehicle, or hybrid electric vehicle.

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