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

[0002] The rapid development of compact and lightweight electronic products, electronic devices, and communication devices, along with the growing need for electric vehicles to address environmental issues, has led to a demand for improved performance in the secondary batteries used as power sources for these products. Among these, lithium secondary batteries have been 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 to provide electrical work.

[0004] Commonly used cathode active materials are lithium transition metal oxides. During charging and / or discharging of a lithium battery, the delithiated cathode active material can slowly react with a non-aqueous or solid electrolyte, gradually degrading the electrochemical performance of a lithium battery using such a cathode active material. It has been demonstrated that treating a cathode active material with a metal such as Ti or Zr (i.e., applying a thin surface layer of the metal onto the cathode active material to increase the amount of the metal in the surface layer) results in a cathode active material that exhibits greater 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 after dry-treating the cathode active material with 0.1 wt% TiO2.

[0006] In US Patent Application Publication No. 2019 / 0006662(A1), 60% A Ti-treated active cathode material containing nickel, 20% manganese, and 20% cobalt is contemplated, where the treated active cathode material is obtained after treating the active cathode material with titanium butoxide in EtOH. Summary of the Invention [Problem to be solved by the invention]

[0007] A drawback associated with these known Ti-treated cathode active materials is that batteries containing the Ti-treated cathode active materials have low cycling efficiency and / or low first discharge capacity. Therefore, there remains a need to provide cathode active materials having an enriched amount of Ti in the surface layer to improve the cycling efficiency of the resulting batteries.

[0008] An 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 cycling 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 of said battery. [Means for solving the problem]

[0012] In a first aspect, the present invention provides a cathode active material for a solid state battery, the cathode active material comprising Li, M', and oxygen, wherein M' is Ni with a content x of 55.0 mol%≦x≦98.0 mol%; Mn with a content y of 0.0 mol%≦y≦45.0 mol%; Co with a content z of 0.0 mol%≦z≦45.0 mol%; D having a content a of 0.0 mol%≦a≦5.0 mol%, which is at least one element other than Li, Ni, Mn, Co, Ti, and O; and Ti with a content b of 0.01 mol%≦b≦5.0 mol%, x, y, z, a, and b are 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 a surface layer.

[0013] The present inventors have surprisingly found that the cathode active material of the present invention significantly improves the cycling efficiency of batteries, particularly sulfide solid state batteries. The cathode active material of the present invention also exhibits a high initial discharge capacity. Preferably, the processed cathode active material containing polycrystalline particles outperforms the corresponding single-crystal cathode active material defined herein or the cathode active material containing single particles and / or secondary particles in terms of cycling efficiency.

[0014] Without being bound by any theory, the inventors believe that in order to obtain a lithium titanium oxide compound as an effective treatment for a positive electrode active material, it is necessary to add a Li source as a treatment agent together with a Ti source.

[0015] In a further aspect, the present invention provides a method for producing the cathode active material.

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

[0017] In a further aspect, the present invention provides the use of the battery. DETAILED DESCRIPTION OF THE INVENTION

[0018] In the following detailed description, preferred embodiments are described in detail to facilitate the practice of the present invention. While the present invention has been described with reference to these specific preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention encompasses numerous alternatives, modifications, and equivalents, as will become apparent from consideration of the following detailed description and the accompanying drawings.

[0019] The term "comprising" as used in the present specification and claims should not be interpreted as being limited to the means listed thereafter, nor does it exclude other elements or steps. It should be interpreted as specifying the presence of the stated features, integers, steps, or ingredients exactly as mentioned, but without excluding the presence or addition of one or more other features, integers, steps, or ingredients, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to a composition consisting only of components A and B. It means that, in the context of the present invention, the only relevant components of the composition are A and B. 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 contains only solid or substantially solid components, such as solid electrodes (e.g., anode and cathode) and a solid electrolyte.

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

[0022] The term "slurry" as used in this specification and claims refers to a mixture, pre-mixture, and / or admixture of solid particles suspended in a liquid, such as water, alcohol, or a combination thereof. When using the term "slurry," the solid particles are not dissolved or not completely dissolved in the liquid. For example, a slurry of a lithium transition metal-based oxide compound is a suspension of particles constituting the lithium transition metal-based oxide compound in a liquid. In other words, the particles constituting the lithium transition metal-based oxide compound are not dissolved or not completely dissolved in the liquid.

[0023] In the context of the present invention, the terms "solid" and "liquid" shall be considered to be solids and liquids at standard conditions of temperature and pressure as defined by IUPAC, unless otherwise defined, whereby boiling points and melting points shall be considered to be boiling points and melting points at standard atmospheric pressure, i.e., 101325 Pa.

[0024] positive electrode active material In a first aspect, the present invention provides a cathode active material for a solid state battery, the cathode active material comprising Li, M′, and oxygen, wherein M′ is: Ni with a content x of 55.0 mol%≦x≦98.0 mol%; Mn with a content y of 0.0 mol%≦y≦45.0 mol%; Co with a content z of 0.0 mol%≦z≦45.0 mol%; D having a content a of 0.0 mol%≦a≦5.0 mol%, which is 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 is 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 specific preferred 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 specific preferred 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%. [[ID=​​​​​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 limitation 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 Mn content 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 Mn content 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 Co content 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 containing 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, wherein 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, wherein 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 a cathode active material of the present invention having a carbon content greater than 0.020 wt. %, preferably greater than 0.030 wt. %, and more preferably greater than 0.045 wt. %, based on the total weight of the cathode active material. A preferred embodiment is a cathode active material of the present invention having a carbon content less than 0.10 wt. %, preferably less than 0.080 wt. %, and more preferably less than 0.065 wt. %, based on the total weight of the cathode active material. A preferred embodiment is a cathode active material of the present invention having a carbon content in the range of 0.020 wt. % to 0.10 wt. %, preferably 0.030 wt. % to 0.080 wt. %, and more preferably 0.045 wt. % to 0.065 wt. %, based on the total weight of the cathode active material. As will be appreciated by those skilled in the art, carbon content can be analyzed using a carbon analyzer. For example, but not by way of limitation to the present invention, a Horiba Emia-Expert carbon / sulfur analyzer can be used.

[0034] A preferred embodiment is a cathode active material of the present invention in which 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 a cathode active material of the present invention in which 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 a cathode active material of the present invention in which 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 will be understood by those skilled in the art, the Li / M' ratio, preferably the Li / (Ni+Mn+Co) ratio, is a molar ratio (mol / mol).

[0035] In a highly preferred embodiment, the positive electrode active material has the formula 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 because x2+y2+z2+a2+b2=1.00.

[0036] In a highly preferred embodiment, 0.99≦w2≦1.01, preferably w2 is about 1.00.

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

[0038] In a highly preferred embodiment, 0.06≦y2≦0.08, preferably y2 is about 0.07.

[0039] In a highly preferred embodiment, 0.08≦z2≦0.10, preferably z2 is about 0.09.

[0040] In a highly preferred embodiment, 0.0≦a2≦0.01, preferably a2 is about 0.0.

[0041] In a highly preferred embodiment, 0.01≦b2≦0.05, 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 is

[0043]

number

[0044] Ti content defined as Ti A The positive electrode active material has a Ti content of Ti determined by XPS analysis. B and Ti B is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni and Ti measured by XPS analysis, and the ratio Ti B / Ti A >25.

[0045] A more preferred embodiment is B / Ti A >50.0, preferably with a ratio Ti B / Ti A >75.0, more preferably the ratio Ti B / Ti A >100.0, even more preferably the ratio Ti B / Ti A >125.0, most preferably the ratio Ti B / Ti A >150.0.

[0046] A more preferred embodiment is B / Ti A <1250.0, preferably ratio Ti B / Ti A <1000.0, more preferably the ratio Ti B / Ti A <750.0, even more preferably the ratio Ti B / Ti A <500.0, most preferably the ratio Ti B / Ti A <250.0.

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

[0048] In the context of the present invention, Ti B is the mole fraction of Ti measured in a region defined between a first point on the outer edge of a particle of a positive electrode active material according to the present invention and a second point at a certain distance from the first point. The distance separating the second point from the first point is equal to the XPS penetration depth, 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 an imaginary line tangent to the outer edge and passing through the first point.

[0049] The outer edge of a particle is, in the context of the present invention, the boundary or outer limit that distinguishes the particle from its external environment. Therefore, XPS analysis provides the atomic content of elements in the top layer of the particle at a penetration depth of approximately 10.0 nm from the particle's periphery. The particle's periphery is also referred to as the "surface." For example, and not limiting to the present invention, XPS analysis is performed using a Thermo K-α+ spectrometer (Thermo Scientific).

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

[0051] As will be appreciated by those skilled in the art, the defined ratio Ti B / Ti Ameans that the positive electrode active material of the present invention has an enriched amount of Ti in the surface layer of the positive electrode active material. The surface layer of the positive electrode active material is the topmost 1 to 10 nm of the positive electrode active material. In other words, the positive electrode active material of the present invention has a surface layer of Ti.

[0052] In the context of the present invention, the positive electrode active material comprises a first surface layer comprising D, where 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; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W, and a surface layer of Ti may be disposed on the first surface layer, and / or the first surface layer may be disposed on a surface layer of Ti, and / or the positive electrode active material layer may comprise a mixed surface layer comprising a surface layer of Ti and the first surface layer.

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

[0054] A preferred embodiment is a ratio Li B / Li A >1.0.

[0055] A more preferred embodiment is a ratio Li B / Li A >2.0, preferably with a ratio of Li B / Li A >2.5, more preferably the ratio Li B / Li A >3.0, even more preferably the ratio Li B / LiA >3.5, most preferably the ratio Li B / Li A The positive electrode active material of the present invention has a refractive index of 0.01 to 0.01, and the refractive index is 0.01 to 0.01.

[0056] A more preferred embodiment is a ratio Li B / Li A <60.0, preferably ratio Li B / Li A <45.0, more preferably the ratio Li B / Li A <30.0, even more preferably the ratio Li B / Li A <20.0, most preferably the ratio Li B / Li A <10.0.

[0057] A more preferred embodiment is a ratio Li B / Li A Ga / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A The positive electrode active material of the present invention relates to a positive electrode active material in which the value of β is 4.0 to 10.0.

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

[0059] As will be appreciated by those skilled in the art, the defined ratio Li B / Li Ameans that the positive electrode active material of the present invention has an enriched amount of Li in the surface layer of the positive electrode active material. The surface layer of the positive electrode active material is the topmost 1 to 10 nm of the positive electrode active material. In other words, the positive electrode active material of the present invention forms a surface layer of Li.

[0060] In the context of the present invention, the positive electrode active material can comprise a second surface layer comprising D, where 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; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W, and a surface layer of Li can be disposed on the second surface layer, and / or the second surface layer can be disposed on a surface layer of Li, and / or the positive electrode active material layer can comprise a mixed surface layer comprising a surface layer of Li and the second surface layer.

[0061] A preferred embodiment is a ratio Li B / Ti B >1.0.

[0062] A more preferred embodiment is a ratio Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >3.0, more preferably the ratio Li B / Ti B >4.0, even more preferably the ratio Li B / Ti B >5.0, most preferably the ratio Li B / Ti B The positive electrode active material of the present invention has a refractive index of 0.05 to 0.5.

[0063] A more preferred embodiment is a ratio Li B / Ti B <100.0, preferably ratio Li B / Ti B <60.0, more preferably the ratio Li B / Ti B <45.0, even more preferably the ratio Li B / Ti B<30.0, most preferably the ratio Li B / Ti B <10.0.

[0064] A more preferred embodiment is a ratio Li B / Ti B is 2.0 to 60.0, preferably the ratio Li B / Ti B is 4.0 to 30.0, more preferably the ratio Li B / Ti B The positive electrode active material of the present invention relates to a positive electrode active material in which the value of σ is 6.0 to 10.0.

[0065] As will be appreciated by those skilled in the art, the defined ratio Li B / Ti B means that the positive electrode active material of the present invention has specific amounts 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 topmost 1 to 10 nm of the positive electrode active material.

[0066] In the context of the present invention, the positive electrode active material may comprise a third surface layer comprising D, where 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; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W; and a surface layer of Ti and Li may be disposed on the third surface layer, and / or the third surface layer may be disposed on the surface layer of Ti and Li, and / or the positive electrode active material layer may comprise a mixed surface layer comprising the surface layer of Ti and Li and the third surface layer.

[0067] Certain preferred embodiments include: ratioTi B / Ti A >25.0, and Ratio Li B / Li A >1.0.

[0068] Certain preferred embodiments include: ratioTi B / Ti A >50.0, preferably with a ratio Ti B / Ti A >75.0, more preferably the ratio Ti B / Ti A >100.0; and Ratio Li B / Li A >2.0, preferably with a ratio of Li B / Li A >3.0, more preferably the ratio Li B / Li A The positive electrode active material of the present invention has a refractive index of 0.01 to 0.01, and the refractive index is 0.01 to 0.01.

[0069] Certain preferred embodiments include: ratioTi B / Ti A <1000.0, preferably ratio Ti B / Ti A <500.0, more preferably ratio Ti B / Ti A <250.0; and Ratio Li B / Li A <60.0, preferably ratio Li B / Li A <30.0, more preferably the ratio Li B / Li A <10.0.

[0070] Certain preferred embodiments include: ratio Ti B / Ti A is in the range of 50.0 to 1000, and preferably the ratio Ti B / Ti A is in the range of 75.0 to 500.0, and more preferably the ratio Ti B / Ti A is in the range of 100.0 to 250.0; Ratio Li B / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li AThe positive electrode active material of the present invention relates to a positive electrode active material in which the value of β is 4.0 to 10.0.

[0071] Certain preferred embodiments include: ratio Ti B / Ti A >25.0, and Ratio Li B / Ti B >1.0.

[0072] Certain preferred embodiments include: ratio Ti B / Ti A >50.0, preferably with a ratio Ti B / Ti A >75.0, more preferably the ratio Ti B / Ti A >100.0; and Ratio Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >4.0, most preferably the ratio Li B / Ti B The positive electrode active material of the present invention has a refractive index of 0.05 to 0.5.

[0073] Certain preferred embodiments include: ratio Ti B / Ti A <1000.0, preferably ratio Ti B / Ti A <500.0, more preferably ratio Ti B / Ti A <250.0; and Ratio Li B / Ti B <100.0, preferably ratio Li B / Ti B <30.0, more preferably the ratio Li B / Ti B <10.0.

[0074] Certain preferred embodiments include: ratio Ti B / Ti Ais in the range of 50.0 to 1000, and preferably the ratio Ti B / Ti A is in the range of 75.0 to 500.0, and more preferably the ratio Ti B / Ti A is in the range of 100.0 to 250.0; Ratio Li B / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A The positive electrode active material of the present invention relates to a positive electrode active material in which the value of β is 4.0 to 10.0.

[0075] Certain preferred embodiments include: Ratio Li B / Li A >1.0, and Ratio Li B / Ti B >1.0.

[0076] Certain preferred embodiments include: Ratio Li B / Li A >2.0, preferably with a ratio of Li B / Li A >3.0, more preferably the ratio Li B / Li A >4.0; and Ratio Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >4.0, more preferably the ratio Li B / Ti B The positive electrode active material of the present invention has a refractive index of 0.05 to 0.5.

[0077] Certain preferred embodiments include: Ratio Li B / Li A <60.0, preferably ratio Li B / Li A <30.0, more preferably the ratio Li B / LiA <10.0; and Ratio Li B / Ti B <100.0, preferably ratio Li B / Ti B <30.0, more preferably the ratio Li B / Ti B <10.0.

[0078] Certain preferred embodiments include: Ratio Li B / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A is 4.0 to 10.0, Ratio Li B / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A The positive electrode active material of the present invention relates to a positive electrode active material in which the value of β is 4.0 to 10.0.

[0079] Certain preferred embodiments include: ratioTi B / Ti A >25.0; Ratio Li B / Li A >1.0, and Ratio Li B / Ti B >1.0.

[0080] Certain preferred embodiments include: ratioTi B / Ti A >50.0, preferably with a ratio Ti B / Ti A >75.0, more preferably the ratio Ti B / Ti A >100.0; Ratio LiB / Li A >2.0, preferably with a ratio of Li B / Li A >3.0, more preferably the ratio Li B / Li A >4.0; and Ratio Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >4.0, more preferably the ratio Li B / Ti B The positive electrode active material of the present invention has a refractive index of 0.05 to 0.5.

[0081] Certain preferred embodiments include: ratio Ti B / Ti A <1000.0, preferably ratio Ti B / Ti A <500.0, more preferably ratio Ti B / Ti A <250.0; Ratio Li B / Li A <60.0, preferably ratio Li B / Li A <30.0, more preferably the ratio Li B / Li A <10.0; and Ratio Li B / Ti B <100.0, preferably ratio Li B / Ti B <30.0, most preferably the ratio Li B / Ti B <10.0.

[0082] Certain preferred embodiments include: ratio Ti B / Ti A is in the range of 50.0 to 1000, and preferably the ratio Ti B / Ti A is in the range of 75.0 to 500.0, and more preferably, the ratio Ti B / Ti A is in the range of 100.0 to 250.0, Ratio Li B / Li A is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A is 4.0 to 10.0, Ratio Li B / Ti B is 2.0 to 60.0, and preferably the ratio Li B / Li A is 3.0 to 30.0, and more preferably the ratio Li B / Li A The positive electrode active material of the present invention relates to a positive electrode active material in which the value of β is 4.0 to 10.0.

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

[0084] In certain preferred embodiments, the cathode active material of the present invention comprises single-crystal particles having a carbon content greater than 0.020 wt %, preferably greater than 0.025 wt %, and more preferably greater than 0.030 wt %, based on the total weight of the cathode active material. In certain preferred embodiments, the cathode active material of the present invention comprises single-crystal particles having a carbon content less than 0.050 wt %, preferably less than 0.040 wt %, and more preferably less than 0.035 wt %, based on the total weight of the cathode active material. In certain preferred embodiments, the cathode active material of the present invention comprises single-crystal particles having a carbon content in the range of 0.020 wt % to 0.050 wt %, preferably 0.025 wt % to 0.040 wt %, and more preferably 0.030 wt % to 0.035 wt %, based on the total weight of the cathode active material.

[0085] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Li A >2.0, preferably with a ratio of Li B / Li A >2.5, more preferably the ratio Li B / Li A In certain preferred embodiments, the positive electrode active material of the present invention comprises single-crystal particles having a ratio Li > 3.0. B / Li A <8.0, preferably ratio Li B / Li A <7.0, more preferably the ratio Li B / Li A In certain preferred embodiments, the cathode active material of the present invention comprises single-crystal particles having a ratio Li<0.05<0.05. B / Li A is in the range of 2.0 to 8.0, and preferably the ratio Li B / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A The particle size includes single crystal particles having a value in the range of 3.0 to 6.0.

[0086] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >2.5, more preferably the ratio Li B / Ti B In certain preferred embodiments, the positive electrode active material of the present invention comprises single-crystal particles having a ratio Li > 3.0. B / Ti B <7.0, preferably ratio Li B / Ti B <6.0, more preferably the ratio Li B / Ti B In certain preferred embodiments, the cathode active material of the present invention comprises single-crystal particles having a ratio Li<5.0. B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The particle contains single crystal particles having a value in the range of 3.0 to 5.0.

[0087] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains single crystal particles, a carbon content in the range of 0.020 wt % and 0.50 wt %, preferably 0.025 wt % and 0.040 wt %, more preferably 0.030 wt % to 0.050 wt %, based on the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 2.0 to 8.0, and preferably the ratio Li B / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A The positive electrode active material has a value in the range of 3.0 to 6.0.

[0088] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains single crystal particles, a carbon content in the range of 0.020 wt % to 0.50 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.025 wt % to 0.040 wt %, and more preferably a carbon content in the range of 0.030 wt % to 0.050 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 3.0 to 5.0.

[0089] Certain preferred embodiments include a positive electrode active material comprising: Contains single crystal particles, a carbon content in the range of 0.020 wt % to 0.50 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.025 wt % to 0.040 wt %, and more preferably a carbon content in the range of 0.030 wt % to 0.050 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 2.0 to 8.0, and preferably the ratio Li B / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A is in the range of 3.0 to 6.0, Ratio Li B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 3.0 to 5.0.

[0090] Certain preferred embodiments include a positive electrode active material comprising: Contains single crystal particles, The particles had a Co content, Co, measured by cross-sectional EDS (CS-EDS) at the edge of the particle. edge Co edge is expressed as mol% of the sum of the Ni, Mn, and Co contents measured by CS-EDS at the edge of the particle, and the Co content, Co, measured by CS-EDS at the center of the particle. center Co center is expressed as mol% relative to the sum of Ni, Mn, and Co contents measured by CS-EDS at the center of the particle, and the ratio 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 for the positive electrode active material.

[0091] In the framework of the present invention, the edge of a particle is the boundary or outer limit that separates the particle from its external environment. The center of a particle is the midpoint of the longest line connecting two points on the edge of the particle.

[0092] Certain preferred embodiments include a positive electrode active material comprising: Contains single crystal particles, The particles,

[0093]

number

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

[0095] Certain preferred embodiments include a positive electrode active material comprising: Contains single crystal particles, The particles had a Co content, Co, measured by cross-sectional EDS (CS-EDS) at the edge of the particle. edge Co edge is expressed as mol% of the sum of the Ni, Mn, and Co contents measured by CS-EDS at the edge of the particle, and the Co content, Co, measured by CS-EDS at the center of the particle. center Co center is expressed as mol% relative to the sum of Ni, Mn, and Co contents measured by CS-EDS at the center of the particle, and the ratio 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, The particles are

[0096]

number

[0097] Al content, Al, defined as: where c is the Al content measured by XPS. A The positive electrode active material has an Al content determined by XPS analysis.B and Al B is expressed as the mole fraction compared to the sum of the mole fractions of Co, Mn, Ni and Al measured by XPS analysis, and the ratio Al B / Al A >1.0, preferably with a ratio of Al B / Al A >2.0, more preferably Al B / Al A >2.5, even more preferably the ratio Al B / Al A >3.0, even more preferably the ratio Al B / Al A >3.5, most preferably the ratio Al B / Al A >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 will be understood by those skilled in the art, in these certain preferred embodiments, all embodiments relating to single-crystal particles apply equally to monolithic particles as defined in the present invention.

[0099] In a particularly preferred embodiment, the positive electrode active material of the present invention comprises single particles and / or secondary particles, and as observed in an SEM image, each single particle consists of only one primary particle, and each secondary particle 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 the SEM image 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 ) is required within the field of view.

[0100] The particles in the image must be properly dispersed, thus avoiding overlap between particles. This can be achieved by placing a small amount of powder sample on an adhesive attached to an SEM sample holder and blowing air through it to remove excess powder. In the context of this invention, primary particles are distinguished from one another in SEM images by observing the grain boundaries between them. 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 crystalline discontinuity.

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

[0102] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Li A >2.0, preferably with a ratio of Li B / Li A >2.5, more preferably the ratio Li B / Li A In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles having a ratio Li > 3.0. B / Li A <8.0, preferably ratio Li B / LiA <7.0, more preferably the ratio Li B / Li A In certain preferred embodiments, the cathode active material of the present invention comprises single particles and / or secondary particles having a ratio Li<6.0. B / Li A is in the range of 2.0 to 8.0, and preferably the ratio Li B / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A The particle size includes single particles and / or secondary particles having a value in the range of 3.0 to 6.0.

[0103] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Ti B >2.0, preferably with a ratio of Li B / Ti B >2.5, more preferably the ratio Li B / Ti B In certain preferred embodiments, the positive electrode active material of the present invention comprises single particles and / or secondary particles having a ratio Li > 3.0. B / Ti B <7.0, preferably ratio Li B / Ti B <6.0, more preferably the ratio Li B / Ti B In certain preferred embodiments, the cathode active material of the present invention comprises single particles and / or secondary particles having a ratio Li<5.0. B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The particle size includes single particles and / or secondary particles having a value in the range of 3.0 to 5.0.

[0104] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains single particles and / or secondary particles, a carbon content in the range of 0.020 wt % to 0.50 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.025 wt % to 0.040 wt %, and more preferably a carbon content in the range of 0.030 wt % to 0.050 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 2.0 to 8.0, and preferably the ratio Li B / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A The positive electrode active material has a value in the range of 3.0 to 6.0.

[0105] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains single particles and / or secondary particles, a carbon content in the range of 0.020 wt % to 0.50 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.025 wt % to 0.040 wt %, and more preferably a carbon content in the range of 0.030 wt % to 0.050 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 3.0 to 5.0.

[0106] Certain preferred embodiments include a positive electrode active material comprising: Contains single particles and / or secondary particles, a carbon content in the range of 0.020 wt % to 0.50 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.025 wt % to 0.040 wt %, and more preferably a carbon content in the range of 0.030 wt % to 0.050 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 2.0 to 8.0, and preferably the ratio LiB / Li A is in the range of 2.5 to 7.0, and more preferably the ratio Li B / Li A is in the range of 3.0 to 6.0, Ratio Li B / Ti B is in the range of 2.0 to 7.0, and preferably the ratio Li B / Ti B is in the range of 2.5 to 6.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 3.0 to 5.0.

[0107] Certain preferred embodiments include a positive electrode active material comprising: Contains single particles and / or secondary particles, The particles had a Co content, Co, measured by cross-sectional EDS (CS-EDS) at the edge of the particle. edge Co edge is expressed as mol% of the sum of the Ni, Mn, and Co contents measured by CS-EDS at the edge of the particle, and the Co content, Co, measured by CS-EDS at the center of the particle. center Co center is expressed as mol% relative to the sum of Ni, Mn, and Co contents measured by CS-EDS at the center of the particle, and the ratio 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.

[0108] In the framework of the present invention, the edge of a particle is the boundary or outer limit that separates the particle from its external environment. The center of a particle is the midpoint of the longest line connecting two points on the edge of the particle.

[0109] Certain preferred embodiments include a positive electrode active material comprising: Contains single particles and / or secondary particles, The particles are

[0110]

number

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

[0112] Certain preferred embodiments include a positive electrode active material comprising: Contains single particles and / or secondary particles, The particles had a Co content, Co, measured by cross-sectional EDS (CS-EDS) at the edge of the particle. edge Co edge is expressed as mol% of the sum of the Ni, Mn, and Co contents measured by CS-EDS at the edge of the particle, and the Co content, Co, measured by CS-EDS at the center of the particle. center Co center is expressed as mol% relative to the sum of Ni, Mn, and Co contents measured by CS-EDS at the center of the particle, and the ratio 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, The particles,

[0113]

number

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

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

[0116] In certain preferred embodiments, the polycrystalline particles are formed by agglomeration of more than 20 primary particles, preferably 50 or more primary particles, and more preferably 100 or more primary particles. Thus, in certain preferred embodiments, the positive electrode active material is a powder containing polycrystalline particles, each of which is composed of more than 20 primary particles, preferably 50 or more primary particles, and more preferably 100 or more primary particles, as observed in an SEM image.

[0117] Preferably, at least 30% of the particles constituting the powder observed in the SEM image, more preferably at least 50% of the particles, 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 ) field of view. The particles in the image must be properly dispersed, thus avoiding overlap between particles. This can be achieved by placing a small amount of powder sample on an adhesive attached to the SEM sample holder and blowing air over it to remove excess powder.

[0118] In certain preferred embodiments, the cathode active material of the present invention comprises polycrystalline particles having a carbon content greater than 0.035 wt %, preferably greater than 0.040 wt %, and more preferably greater than 0.045 wt %, based on the total weight of the cathode active material. In certain preferred embodiments, the cathode active material of the present invention comprises polycrystalline particles having a carbon content less than 0.075 wt %, preferably less than 0.070 wt %, and more preferably less than 0.065 wt %, based on the total weight of the cathode active material. In certain preferred embodiments, the cathode active material comprises polycrystalline particles having a carbon content in the range of 0.035 wt % to 0.075 wt %, preferably 0.040 wt % to 0.070 wt %, and more preferably 0.045 wt % to 0.065 wt %, based on the total weight of the cathode active material.

[0119] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Li A >3.0, preferably with a ratio of Li B / Li A >3.5, more preferably the ratio Li B / Li A In certain preferred embodiments, the positive electrode active material of the present invention comprises polycrystalline particles having a ratio Li > 4.0. B / Li A <10.0, preferably ratio Li B / Li A <9.0, more preferably the ratio Li B / Li A In certain preferred embodiments, the cathode active material of the present invention comprises polycrystalline particles having a ratio Li<8.5. B / Li A is in the range of 3.0 to 10.0, and preferably the ratio Li B / Li A is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A The polycrystalline particles have a σ in the range of 4.0 to 8.5.

[0120] In certain preferred embodiments, the cathode active material of the present invention has a ratio of Li B / Ti B >4.0, preferably relative Li B / Ti B >5.0, more preferably the ratio Li B / Ti B In certain preferred embodiments, the positive electrode active material of the present invention comprises polycrystalline particles having a ratio Li > 6.0. B / Ti B <12.0, preferably ratio Li B / Ti B <11.0, more preferably the ratio Li B / Ti B In certain preferred embodiments, the cathode active material of the present invention comprises polycrystalline particles having a ratio Li<10.0. B / Ti B is in the range of 4.0 to 12.0, and preferably the ratio Li B / Ti B is in the range of 5.0 to 11.0, and more preferably the ratio Li B / Ti B It contains polycrystalline particles having a value in the range of 6.0 to 10.0.

[0121] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains polycrystalline particles, a carbon content in the range of 0.035 wt % to 0.075 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.040 wt % to 0.070 wt %, and more preferably a carbon content in the range of 0.045 wt % to 0.065 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 3.0 to 10.0, and preferably the ratio Li B / Li A is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A The positive electrode active material has a value in the range of 4.0 to 8.5.

[0122] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains polycrystalline particles, a carbon content in the range of 0.035 wt % to 0.075 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.040 wt % to 0.070 wt %, and more preferably a carbon content in the range of 0.045 wt % to 0.065 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Ti B is in the range of 4.0 to 12.0, and preferably the ratio Li B / Ti B is in the range of 5.0 to 11.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 6.0 to 10.0.

[0123] A particularly preferred embodiment is a cathode active material of the present invention, comprising: Contains polycrystalline particles, a carbon content in the range of 0.035 wt % to 0.075 wt % relative to the total weight of the positive electrode active material, preferably a carbon content in the range of 0.040 wt % to 0.070 wt %, and more preferably a carbon content in the range of 0.045 wt % to 0.065 wt % relative to the total weight of the positive electrode active material; Ratio Li B / Li A is in the range of 3.0 to 10.0, and preferably the ratio Li B / Li A is in the range of 3.5 to 9.0, and more preferably the ratio Li B / Li A is in the range of 4.0 to 8.5, Ratio Li B / Ti B is in the range of 4.0 to 12.0, and preferably the ratio Li B / Ti B is in the range of 5.0 to 11.0, and more preferably the ratio Li B / Ti B The positive electrode active material has a value in the range of 6.0 to 10.0.

[0124] Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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 will be understood by those skilled in the art, the particle size distribution (PSD) D50 of cathode active material powders is measured by laser diffraction particle size analysis. For example, and not by way of limitation, the particle median D50 can be measured using a Malvern Mastersizer 3000.

[0125] Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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 will be understood by those skilled in the art, the particle size distribution (PSD) D50 of cathode active material powders is measured by laser diffraction particle size analysis. For example, but not by way of limitation 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] Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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. Certain preferred embodiments relate to cathode active materials 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 will be understood by those skilled in the art, the particle size distribution (PSD) D50 of cathode active material powders is measured by laser diffraction particle size analysis. For example, but not by way of limitation 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 aspect, the present invention provides a method for producing a cathode active material, comprising: preparing a slurry of a lithium transition metal based oxide compound, a first lithium source, water, and an alcohol; mixing the slurry with a Ti source; and heating the mixture at a temperature of 250° C. or higher and lower than 500° C. for a period of 1 hour to 20 hours to obtain a positive electrode active material.

[0128] In a highly preferred embodiment of the method of making an active cathode material of the present invention, the active cathode material is according to the first aspect of the present invention. As will be appreciated by those skilled in the art, when the method of making an active cathode material of the present invention provides a cathode material according to the first aspect of the present invention, all embodiments relating to the active cathode material according to the first aspect of the present invention apply mutatis mutandis to the method of making an active cathode material according to the first aspect of the present invention. For example, Li, M', Ti as described herein in the context of the active cathode material may be used. A , Ti B , Li A and Li BThe various embodiments regarding the identity and amount of are equally applicable to methods of preparing positive electrode active materials.

[0129] In a preferred embodiment of the present method, the lithium transition metal-based oxide compound comprises Li, M', and oxygen, where M' comprises Ni, Mn, Co, and D, where 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; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W. Preferably, the lithium transition metal-based oxide used is also typically prepared according to a lithiation process, which is a process in which a mixture of a transition metal oxide precursor and a second lithium source is heated at a temperature of preferably at least 500°C and at most 1000°C. Typically, the transition metal precursor is prepared by co-precipitation 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, e.g., 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-based oxide compound, as described herein, includes single crystal particles or single particles and / or secondary particles, and is further mixed with a Co source, such as Co3O4, and a third lithium source, preferably metallic lithium or a lithium salt, preferably a lithium salt such as LiOH, where 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-based oxide compound is further ground with alumina in an amount of 250 to 750 ppm relative to the total amount of the positive electrode active material, and sieved.

[0130] In a preferred embodiment of the 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 solids content of greater than 40 wt% (based on the total weight of the slurry), preferably greater than 50 wt% solids, and more preferably greater than 55 wt% solids (based on the total weight of the slurry). In a preferred embodiment, the slurry has a solids content of less than 80 wt% (based on the total weight of the slurry), preferably less than 70 wt% solids, and more preferably less than 65 wt% solids (based on the total weight of the slurry). In a preferred embodiment, the slurry has a solids content in the range of 40 wt% to 80 wt% (based on the total weight of the slurry), preferably a solids content in the range of 50 wt% to 70 wt%, and more preferably a solids content in the range of 55 wt% to 65 wt% (based on the total weight of the slurry).

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

[0133] In a preferred embodiment of the 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 the 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 the 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% relative to the metal content in the lithium transition metal oxide compound, preferably 0.7 mol% to 10.0 mol%, 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%, more preferably 0.5 mol% to 1.5 mol%, based on the metal content in the lithium transition metal oxide compound. In a preferred embodiment, the Ti source is a Ti alkoxide, preferably Ti ethoxide, Ti propoxide, or Ti butoxide, more preferably 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, which contains the Ti alkoxide and an additional alcohol, and the alkoxide group is the conjugate base of the additional alcohol. For example, the Ti alkoxide is Ti(IV) propoxide dissolved in propanol. Typically, the solution contains 50 to 90 wt% of the Ti alkoxide based on the total weight of the solution. Examples of such solutions are 70 wt% Ti(IV) isopropoxide in 1-propanol or 80 wt% Ti(IV) butoxide in 1-butanol.

[0139] A preferred embodiment of the method comprises: At a temperature of 275°C to 450°C, preferably 300°C to 400°C, more preferably 325°C to 375°C, Heating is carried out for 2 to 15 hours, preferably 3 to 10 hours, and more preferably 4 to 7 hours.

[0140] A preferred embodiment of the method is to heat the mixture under an oxidizing atmosphere, preferably comprising or consisting of oxygen, such as air.

[0141] In a more preferred embodiment, the heating is carried out in a furnace.

[0142] In certain preferred embodiments, the method includes the further step of filtering and drying the mixture prior to heating the mixture. 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 at most 20 hours. As will be appreciated by those skilled in the art, filtering the mixture can be accomplished by conventional filtration techniques known in the art.

[0143] In certain preferred embodiments, the method comprises the further step of drying the mixture before heating it, preferably under vacuum, under vacuum heating, or under a constant flow of N2 gas for at least 4 hours and at most 20 hours.

[0144] Product by Process In a third aspect, the present invention relates to a cathode active material obtainable by the method according to the second aspect of the present invention.

[0145] As will be appreciated by those skilled in the art, all embodiments relating to the active cathode material according to the first aspect of the present invention and / or the process according to the second aspect of the present invention apply mutatis mutandis to the active cathode material obtained by the process according to the present invention. For example, Li, M', Ti described herein in the context of the active cathode material A , Ti B , Li A and Li BThe various embodiments regarding the identity and amount of are equally applicable to the active cathode material obtained by the method for preparing the active cathode material.

[0146] battery In a fourth aspect, the present invention relates to a battery comprising an active cathode material according to the first aspect of the invention and / or an active cathode material obtainable by the method according to the third aspect of the invention.

[0147] In a preferred embodiment, the battery is a solid-state battery. Preferably, the solid-state battery includes a sulfide-based electrolyte. Preferably, the electrolyte is a sulfide-based solid electrolyte, and more preferably, the electrolyte includes 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 In a highly preferred embodiment, the battery is a sulfide solid state battery.

[0148] Preferably, the solid-state battery further comprises an anode comprising an active anode material. Suitable electrochemically active anode materials are known in the art. For example, the anode may comprise graphitic carbon, metallic lithium, or a lithium-containing metal alloy, such as a Li-In alloy, as the active anode 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 will be appreciated by those skilled in the art, the efficiency of a battery can be determined as described in section E2) of the Examples.

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

[0151] use In a fifth aspect, the present invention relates to the use of an active cathode material according to the first aspect of the invention and / or an active cathode material obtainable by the method according to the third aspect of the invention.

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

[0153] In a sixth aspect, 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, an electric vehicle, or in a hybrid electric vehicle, preferably in an electric vehicle or a hybrid electric vehicle. [Example]

[0154] Experimental Tests Used in the Examples In the examples, the following analytical methods are used:

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

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

[0157] C) X-ray photoelectron spectroscopy In the present invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of positive electrode active material powder particles. In XPS measurements, signals are obtained 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 the positive electrode active material powder particles, XPS measurements were performed using a Thermo K-α+ spectrometer (Thermo Scientific). Single-wavelength Al Kα radiation (hυ = 1486.6 eV) was used with a spot size of 400 μm and a measurement angle of 45°. A broad survey scan to identify the elements present on the surface was performed with a pass energy of 200 eV. The C1s peak with maximum intensity (or center) at a binding energy of 284.8 eV was used as the calibration peak position after data collection. Then, for each identified element, at least 10 precise narrow scans at 50 eV were performed to determine the exact surface composition.

[0159] Curve fitting was performed in CasaXPS version 2.3.19PR1.0 (Casa Software) using Shirley-type background processing and Scofield sensitivity coefficients. Fitting parameters are according to Table 1a. The line shape GL(30) is the Gaussian / Lorentzian product equation with 70% Gaussian and 30% Lorentzian lines.

[0160] [Table 1]

[0161] For Ti and Co peaks, limits are set for each specified peak according to 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, and is calculated as follows:

[0164]

number

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

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

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

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

[0169] Cell assembly The sulfide solid-state battery was assembled in an argon-filled glove box from bottom to top: cathode with Al current collector with a coated portion on top, separator, anode with Li side up, and Cu current collector. The stacked components were pressed together at a pressure of 250 MPa and placed in an external cage to prevent air exposure.

[0170] E2) Test method The test method is a conventional "constant cut-off voltage" test. Conventional cell testing in this invention follows the schedule shown in Table 2. Each cell is cycle tested 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 measured from 4.3V to 2.5V (Li / Li + ) or 3.7V~1.9V(InLi / Li + ) voltage range, at a C rate of 0.1C, in constant current mode (CC).

[0172] The efficiency EF is expressed as a percentage as follows:

[0173]

number

[0174] [Table 3]

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

[0176] Comparative Example 1 A monolithic cathode active material (i.e., a cathode active material including single particles and secondary particles), labeled CEX1.1, was prepared according to the following steps: Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.85 Mn 0.07 Co 0.08 A nickel-based transition metal oxide-hydroxide powder (TMH1) with .sup.-(C1) was prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia.

[0177] Step 2) First Mixing: The prepared TMH1 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 a first heating product.

[0179] Step 4) Wet bead milling: The first heated 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 heated product, followed by drying and sieving to obtain a milled product. The weight ratio of solid to solution for bead milling was 6:4, and the bead milling 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 % Co from CO3O4 and 7.5 mol % Li from LiOH, each 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, followed by grinding and sieving with the addition of 500 ppm alumina powder 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 (i.e., a cathode active material including single particles and secondary particles) labeled EX1.1 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) Preparation of slurry: 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 from step 1) and the slurry prepared from step 2) were mixed and stirred at room temperature for 15 hours, followed by filtration and drying 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 to yield EX1.1, which has an M' containing Ni, Mn, Co, and Ti in a ratio of Ni:Mn:Co:Ti of 0.84:0.07:0.09:0.010 as determined by ICP-OES. EX1.1 has a D50 of 4 μm.

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

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

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

[0191] Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.83 Mn 0.12 Co 0.05 Nickel-based transition metal oxide hydroxide powder (TMH2) with SiO2 was prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia.

[0192] Step 2) First Mixing: The prepared TMH2 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 a first heating product.

[0194] Step 4) Second mixing: The first heating product was mixed with LiOH in an industrial blender to obtain a 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 under an oxidizing atmosphere for 12 hours, then crushed and sieved to obtain CEX2.

[0196] Example 2 A polycrystalline positive electrode 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) Preparation of slurry: 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 from step 1) and the slurry prepared from step 2) were mixed and stirred at room temperature for 15 hours, followed by filtration and drying 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 to yield EX2.1, which has an M' containing Ni, Mn, Co, and Ti in a ratio of Ni:Mn:Co:Ti of 0.83:0.12:0.05:0.006 as determined by ICP-OES. EX2.1 has a D50 of 5.5 μm.

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

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

[0203] result

[0204] [Table 4]

[0205] *Relative to the molar contents 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. B and Li B indicates the atomic ratio (equivalent to the molar ratio) of Li and Ti relative to the total atomic fraction of Ni, Mn, Co, and Ti. The table also compares the results with ICP results. Atomic ratios higher than 1 indicate that the Li and Ti are enriched at the surface of the cathode active material, relative to XPS measurements, where the signal is acquired from the first few nanometers (e.g., 1 nm to 10 nm) of the top layer 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 primarily present on the surface of the cathode active material.

[0206] CEX1.1, CEX1.2, and EX1.1 to EX1.3 are monolithic cathode active materials with a Ni content of 84 mol%. CEX1.1 is the core material, and CEX1.2 is obtained by dry-mixing CEX1.1 with Ti material and subsequently heating. Due to the difference in the process of introducing Ti by preparing a Ti solution, EX1.1 to EX1.3 have a lower Ti content than CEX1.2. B and Ti B / Ti A Furthermore, higher surface Ti content is associated with improved solid-state battery efficiency.

[0207] CEX2 and EX2.1 to EX2.3 are polycrystalline positive electrode 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 than CEX2. B , and Ti B / Ti A This shows a higher Ti content, leading to a higher electrochemical cell efficiency. EX2.3 was prepared according to the same method as EX2.2, except that filtration was replaced by evaporation. Both EX2.2 and EX2.3, which have the same Ti content, show similar electrochemical cell efficiencies.

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

Claims

1. A cathode active material for a solid-state battery, the cathode active material comprising Li, M′, and oxygen, wherein M′ is Ni with a content x, where 55.0 mol%≦x≦98.0 mol%; Mn with a content y of 0.0 mol%≦y≦45.0 mol%; Co with a content z of 0.0 mol%≦z≦45.0 mol%; D having a content a of 0.0 mol%≦a≦5.0 mol%, D being at least one element other than Li, Ni, Mn, Co, Ti, and O; and Ti with a content b, wherein 0.01 mol%≦b≦5.0 mol%, 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 [Equation 1] Ti content defined as Ti Ａ and The positive electrode active material has a Ti content Ti determined by XPS analysis. Ｂ and Ti Ｂ is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti as determined by XPS analysis; ratio Ti Ｂ / Ti Ａ >25.0, The positive electrode active material has a Li content Li determined by ICP analysis Ａ and Li Ａ is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti as determined by ICP analysis; The positive electrode active material has a Li content Li determined by XPS analysis. Ｂ and Li Ｂ is expressed as a mole fraction compared to the sum of the mole fractions of Co, Mn, Ni, and Ti as determined by XPS analysis; Ratio Li Ｂ / Li Ａ >1.

0.

2. 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; preferably Al, B, Cr, Nb, S, Si, Y, Zr, and W; more preferably B, Nb, Zr, and W.

3. Ratio Li Ｂ / Li Ａ >2.0, preferably the ratio Li Ｂ / Li Ａ >3.0, more preferably the ratio Li Ｂ / Li Ａ The positive electrode active material according to claim 2, wherein the σ is >4.

0.

4. Ratio Li Ｂ / Ti Ｂ >2.0, preferably the ratio Li Ｂ / Ti Ｂ >3.0, more preferably the ratio Li Ｂ / Ti Ｂ The positive electrode active material according to claim 1 , wherein the σ is >4.

0.

5. Ratio Li Ｂ / Ti Ｂ <60.0, preferably the ratio Li Ｂ / Ti Ｂ <30.0, more preferably Li Ｂ / Ti Ｂ 2. The positive electrode active material according to claim 1, wherein R is a stoichiometric constant of 1.0 or less.

6. ratio Ti Ｂ / Ti Ａ >50.0, preferably the ratio Ti Ｂ / Ti Ａ >75.0, more preferably the ratio Ti Ｂ / Ti Ａ The positive electrode active material according to claim 1 , wherein the σ is >100.

0.

7. 2. The positive electrode active material according to claim 1, wherein 60.0 mol%≦x≦95.0 mol%, preferably 65.0 mol%≦x≦92.0 mol%, more preferably 70.0 mol%≦x≦90.0 mol%.

8. 2. The positive electrode active material according to claim 1, wherein 0.05 mol%≦b≦2.5 mol%, preferably 0.1 mol%≦b≦2.0 mol%, more preferably 0.2 mol%≦b≦1.5 mol%.

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

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

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

12. 10. The method of claim 9, wherein the Ti source is Ti propoxide or Ti isopropoxide.

13. 10. The method of claim 9, wherein the amount of water in the slurry is 0.5 mol% to 25.0 mol%, preferably 0.7 mol% to 10.0 mol%, more preferably 1.0 mol% to 5.0 mol%, relative to the metal content in the lithium transition metal oxide compound.

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

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

16. 16. The solid-state battery of claim 15, comprising a sulfide-based solid electrolyte comprising Li, P, and S.

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

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