Particle for positive electrode active material

Abstract

The present invention relates to a particle for a positive electrode active material, the positive electrode active material comprising lithium, nickel, cobalt, aluminum, oxygen and manganese, the particle having a Co 边缘 / Co 中心 ratio ≥ 1.1 and an Al 边缘 / Al 中心 ratio ≥ 20.0, wherein Co 边缘 is the atomic ratio of Co to the total amount of Ni, Co and Mn at the edge of the particle, Co 中心 is the atomic ratio of Co to the total amount of Ni, Co and Mn at the center of the particle, Al 边缘 is the atomic ratio of Al to the total amount of Ni, Co and Mn at the edge of the particle, Al 中心 is the atomic ratio of Al to the total amount of Ni, Co and Mn at the center of the particle, and wherein Co 边缘 , Co 中心 , Al 边缘 and Al 中心 are measured by cross-sectional SEM-EDS.

Description

Technical Field

[0001] This invention relates to particles for a positive electrode active material comprising lithium, oxygen, nickel, cobalt, and optionally manganese, wherein the surface layer of the particles has an enriched amount of aluminum and cobalt. The invention also relates to a positive electrode active material comprising the particles, a battery comprising the positive electrode active material, and the use of the battery. Background Technology

[0002] With the rapid development of small and lightweight electronic products, electronic devices, and communication equipment, and the widespread demand for electric vehicles due to environmental concerns, there is a need to improve the performance of secondary batteries used as power sources for these products. Among them, lithium secondary batteries have become a focus 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 detach from the cathode, are transported through the electrolyte, and embed into the anode, while electrons detach from the cathode and are injected into the anode through an external circuit (charger). During the use or discharge of the secondary battery, lithium ions detach from the anode, are transported through the electrolyte, and embed into the cathode, while electrons flow through the external circuit to provide electrical work.

[0004] The commonly used cathode active material is lithium transition metal oxide. During the charging and / or discharging of lithium batteries, delithiated cathode active materials may react slowly with non-aqueous or solid electrolytes, resulting in a gradual decline in the electrochemical performance of lithium batteries using such cathode active materials.

[0005] It has been demonstrated that applying a surface layer containing a metal such as Al to a cathode active material (i.e., applying a thin metal surface layer to the cathode active material such that the amount of said metal in the surface layer increases or is enriched) results in the cathode active material exhibiting improved electrochemical performance compared to its counterparts without said surface layer.

[0006] WO 2022 / 096473 A1 considers the use of Li 1.01 (Ni 0.63 Mn 0.22 Co 0.15 ) 0.99 A positive electrode active material is obtained by mixing O2 compounds with Co3O4 and Al2O3 and heating. However, there is still a need for a particle-based positive electrode active material with improved electrochemical performance.

[0007] The purpose of this invention is to provide particles for a positive electrode active material, the positive electrode active material comprising lithium, oxygen, nickel, cobalt and optionally manganese, wherein the surface layer of the particles has an enriched amount of aluminum and cobalt.

[0008] Another object of the present invention is to provide a positive electrode active material comprising the particles.

[0009] Another object of the present invention is to provide a battery comprising the aforementioned positive electrode active material.

[0010] Another object of the present invention is to provide the use of the battery. Summary of the Invention

[0011] In a first aspect, the object of the present invention is achieved by providing particles for a positive electrode active material comprising lithium, oxygen, nickel, cobalt and optionally manganese, wherein the surface layer of the particles has an enriched amount of aluminum and cobalt.

[0012] The inventors have surprisingly discovered that by further treating the lithium nickel manganese cobalt oxide compound with Co3O4, the resulting positive electrode active material containing the particles exhibits improved electrochemical performance, as illustrated by the reduced DCR (direct current internal resistance) value.

[0013] Without wishing to be bound by any theory, the inventors believe that the improvement in DCR is related to the formation of an ion-conducting phase in the surface layer of the particles, wherein the surface layer comprises Co, Al and optionally F.

[0014] In another aspect, the present invention provides a positive electrode active material comprising the aforementioned particles.

[0015] In another aspect, the present invention provides a battery comprising the aforementioned positive electrode active material.

[0016] In another aspect, the present invention provides the use of the battery. Attached Figure Description

[0017] Figure 1 This is a cross-sectional SEM image of EX1, where A is the location of the particle center, at which Co is measured. 中心 Al 中心 F 中心 Ni 中心 and Mn 中心 And B is the location of the particle edge, where Co is measured. 边缘 Al 边缘 and F 边缘 . Detailed Implementation

[0018] In the following detailed description, preferred embodiments are described in detail to enable the practice of the invention. Although the invention has been described with reference to these specific preferred embodiments, it should be understood that the invention is not limited to these preferred embodiments. Rather, the invention includes numerous alternatives, modifications, and equivalents, as will become apparent from consideration of the following detailed description and drawings.

[0019] As used herein and in the claims, the term “comprising” should not be construed as limited to the manner listed thereafter; it does not exclude other elements or steps. It should be interpreted as specifying the presence of the stated features, integers, steps, or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Therefore, the scope of the expression “composition comprising components A and B” should not be limited to compositions consisting solely of components A and B. This means that, for the purposes of this invention, the only relevant components of the composition are A and B. Therefore, the terms “comprising” and “including” encompass the more restrictive terms “consistently composed of” and “composed of”.

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

[0021] As used herein and in the claims, the term "positive electrode active material" (also known as a cathode active material) is defined as a material that is electrochemically active in a positive or negative electrode. An active material must be understood as a material capable of capturing and releasing Li ions when subjected to a voltage change over a predetermined time period.

[0022] As used herein, the term "positive electrode" is defined as a material comprising a positive electrode active material and other components added to the positive electrode active material, said other components being non-electrochemically active, specifically conductive agents or binders.

[0023] In the context of this invention, unless otherwise defined, the terms "solid" and "liquid" should be understood as solids and liquids under standard temperature and pressure conditions as defined by IUPAC. Therefore, unless otherwise stated, boiling point and melting point should be understood as boiling point and melting point at standard atmospheric pressure (i.e., 101325 Pa).

[0024] In the context of this invention, the elemental content in the positive electrode active material as described herein is measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) methods, for example (but not limiting the invention), using an Agilent ICP 720-OES.

[0025] In the context of this invention, the particle size distribution (PSD) of the positive electrode active material described herein, specifically the D50 value, is defined, for example (but not limiting the invention), as the particle size at 50% of the cumulative volume % distribution obtained by using a Malvern Mastersizer 3000 with a Hydro MV wet dispersion attachment.

[0026] In the context of this invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of the positive electrode active material powder particles. As understood by those skilled in the art, signals are acquired in XPS measurements from the first few nanometers (i.e., 1 nm to 10 nm) of the uppermost part of the sample (i.e., the surface layer). In other words, all elements measured by XPS are contained within the surface layer. Specifically, the penetration depth is the distance along an axis perpendicular to a virtual line tangent to the outer edge and passing through the first point. Preferably, monochromatic Al Kα radiation (hυ = 1486.6 eV) is used, with a spot size of 400 μm and a measurement angle of 45°. Preferably, a wide probe scan is performed at a pass energy of 200 eV to identify elements present at the surface. Preferably, after data collection, the C1s peak with maximum intensity (or intermediate) at a binding energy of 284.8 eV is used as the calibration peak position. Preferably, a precise narrow scan is then performed at 50 eV, with at least 10 scans for each identified element to determine the precise surface composition. For example, but not limited to the present invention, for surface analysis of positive electrode active material powder particles, XPS measurements were performed using a Thermo Kα+ spectrometer. For example, but not limited to the present invention, curve fitting was performed using CasaXPS version 2.3.19PR1.0 with Shirley-type background processing and a Scofield sensitivity factor, wherein preferably, the linear shape GL(30) is a Gaussian / Lorentz product formula with a 70% Gaussian line and a 30% Lorentz line.

[0027] In the context of this invention, the concentrations of relevant elements such as Ni, Mn, Co, Al, and F from the edge to the center of the positive electrode active material particles are obtained using cross-sectional SEM-EDS, and analyzed by energy-dispersive X-ray spectroscopy (EDS). EDS analysis of the positive electrode active material particles provides quantitative elemental analysis of the cross-section, assuming the particles are spherical or approximately spherical. This ensures that the center point of the particle's cross-section is approximately the center point of the particle. Typically, the geometric center of the cross-section can be taken as its center. The cross-section of the positive electrode active material as described herein is prepared using an ion beam cross-section polisher (CP) instrument JEOL (IB-19530CP). Preferably, the instrument uses argon as the beam source. Preferably, to prepare the sample, a small amount of positive electrode active material powder is mixed with resin and a hardener, and the mixture is then heated on a hot plate for 10 minutes; and after heating, it is placed in the ion beam instrument for cutting and the settings are adjusted according to a standard procedure, wherein the voltage is 6.5 kV for 3 hours. Preferably, for each sample, particles with a diameter approximately equal to the D50 value measured by PSD are selected for analysis. Preferably, the EDS consists of a 50 mm [diameter / diameter] from Oxford Instruments. 2 The X-MaxN EDS sensor is performed using a JEOL JSM 7100F SEM instrument. Preferably, a straight line is set from the edge of the particle to the center point, and the concentrations of Ni, Mn, Co, Al, and F are measured at both the edge and the center, and expressed as at% relative to the sum of the Ni, Mn, and Co contents at each point.

[0028] Within the framework of this invention, at% represents atomic percentage. In the expression of concentration, at% or "atomic percentage" of a given element means what percentage of all atoms in the compound are atoms of that element. Furthermore, within the framework of this invention, the symbol at% is equivalent to mol% or "molar percentage".

[0029] Particles

[0030] In a first aspect, the present invention relates to particles for a positive electrode active material, said positive electrode active material comprising lithium, nickel, cobalt, aluminum, oxygen, and optionally manganese, wherein the Co of said particles... 边缘 / Co 中心 The ratio is ≥ 1.1, and Al 边缘 / Al 中心 Ratio ≥ 20.0, Co 边缘 It is the atomic ratio of Co to the total amount of Ni, Co, and Mn at the edge of the particle. Co 中心 It is the atomic ratio of Co to the total amount of Ni, Co, and Mn at the center of the particle. Al 边缘 It is the atomic ratio of Al to the total amount of Ni, Co, and Mn at the edge of the particle. Al 中心 It is the atomic ratio of Al to the total amount of Ni, Co, and Mn at the center of the particle. Co 边缘 Co 中心 Al 边缘 And Al 中心 It was measured using cross-sectional SEM-EDS.

[0031] A highly preferred embodiment is particles for positive electrode active materials used in rechargeable batteries, and more preferably for solid-state batteries.

[0032] In a preferred embodiment, the particles of the present invention have a layered structure, preferably an α-NaFeO2 type layered structure, and more preferably an α-NaFeO2 type layered structure having an R-3m space group.

[0033] In a preferred embodiment, the particles are particles according to the invention, wherein Co 边缘 / Co 中心 The ratio is ≥ 1.2, preferably Co. 边缘 / Co 中心 Ratio ≥ 1.35, more preferably Co 边缘 / Co 中心 The ratio is ≥ 1.5. In a more preferred embodiment, the particles are particles according to the invention, wherein Co 边缘 / Co 中心 Ratio ≤ 50.0, preferably Co 边缘 / Co 中心 Ratio ≤ 10.0, more preferably Co 边缘 / Co 中心 The ratio is ≤ 5.0, and the optimal choice is Co. 边缘 / Co 中心 The ratio is ≤ 3.0. In a more preferred embodiment, the particles are particles according to the invention, wherein Co 边缘 / Co 中心 The ratio is between 1.2 and 50.0, preferably Co. 边缘 / Co 中心 The ratio is between 1.2 and 10.0, more preferably Co. 边缘 / Co 中心 The ratio is between 1.35 and 5.0, with Co being the most preferred. 边缘 / Co 中心 The ratio is between 1.5 and 3.0.

[0034] In a more preferred embodiment, the particles are particles according to the invention, wherein Co边缘 / Co 中心 The ratio is ≥ 1.6, preferably Co. 边缘 / Co 中心 Ratio ≥ 1.65, more preferably Co 边缘 / Co 中心 The ratio is ≥ 1.7. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein Co 边缘 / Co 中心 Ratio ≤ 50.0, preferably Co 边缘 / Co 中心 Ratio ≤ 10.0, more preferably Co 边缘 / Co 中心 The ratio is ≤ 5.0, and the optimal choice is Co. 边缘 / Co 中心 The ratio is ≤ 3.0. In a more preferred embodiment, the particles are particles according to the invention, wherein Co 边缘 / Co 中心 The ratio is between 1.55 and 50.0, preferably Co. 边缘 / Co 中心 The ratio is between 1.6 and 10.0, more preferably Co. 边缘 / Co 中心 The ratio is between 1.65 and 5.0, with Co being the most preferred. 边缘 / Co 中心 The ratio is between 1.7 and 3.0. In a highly preferred embodiment, Co 边缘 / Co 中心 The ratio is between 2.0 and 3.0.

[0035] In a preferred embodiment, the particles are particles according to the invention, wherein Al 边缘 / Al 中心 Ratio ≥ 30.0, preferably Al 边缘 / Al 中心 Ratio ≥ 35.0, more preferably Al 边缘 / Al 中心 The ratio is ≥ 40.0. In a more preferred embodiment, the particles are particles according to the invention, wherein Al 边缘 / Al 中心 The ratio is ≤ 200.0, preferably Al. 边缘 / Al 中心 Ratio ≤ 150.0, more preferably Al 边缘 / Al 中心 The ratio ≤ 100.0, the most preferred option is Al. 边缘 / Al 中心 The ratio is ≤ 75.0. In a more preferred embodiment, the particles are particles according to the invention, wherein Al边缘 / Al 中心 The ratio is between 20.0 and 200.0, preferably Al. 边缘 / Al 中心 The ratio is between 30.0 and 150.0, more preferably Al. 边缘 / Al 中心 The ratio is between 35.0 and 100.0, with Al being the most preferred. 边缘 / Al 中心 The ratio is between 40.0 and 75.0. In a particular preferred embodiment, the particles are particles according to the invention, wherein Al 边缘 / Al 中心 The ratio is between 20.0 and 100.0, preferably Al. 边缘 / Al 中心 The ratio is between 30.0 and 75.0, with Al being more preferred. 边缘 / Al 中心 The ratio is between 35.0 and 60.0.

[0036] In a preferred embodiment, the particles are those according to the invention, whose F 边缘 / F 中心 The ratio is ≥ 1.1, where F 边缘 It is the atomic ratio of F to the total amount of Ni, Co, and Mn at the edge of the particle. 中心 It is the atomic ratio of F to the sum of Ni, Co, and Mn at the center of the particle, where F 边缘 and F 中心 It was measured using cross-sectional SEM-EDS.

[0037] In a more preferred embodiment, the particles are particles according to the invention, wherein F 边缘 / F 中心 Ratio ≥ 1.2, preferably F 边缘 / F 中心 Ratio ≥ 1.3, more preferably F 边缘 / F 中心 The ratio is ≥ 1.4. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein F 边缘 / F 中心 Ratio ≤ 50.0, preferably F 边缘 / F 中心 Ratio ≤ 10.0, more preferably F 边缘 / F 中心 The ratio is ≤ 5.0, and the optimal choice is F. 边缘 / F 中心 The ratio is ≤ 3.0. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein F 边缘 / F中心 The ratio is between 1.1 and 50.0, preferably F. 边缘 / F 中心 The ratio is between 1.2 and 10.0, more preferably F 边缘 / F 中心 The ratio is between 1.4 and 5.0, with F being the most preferred. 边缘 / F 中心 The ratio is between 1.4 and 3.0.

[0038] In a more preferred embodiment, the particles are particles according to the invention, wherein F 边缘 / F 中心 Ratio ≥ 1.5, preferably F 边缘 / F 中心 Ratio ≥ 1.55, more preferably F 边缘 / F 中心 The ratio is ≥ 1.6. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein F 边缘 / F 中心 Ratio ≤ 50.0, preferably F 边缘 / F 中心 Ratio ≤ 10.0, more preferably F 边缘 / F 中心 The ratio is ≤ 5.0, and the optimal choice is F. 边缘 / F 中心 The ratio is ≤ 3.0. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein F 边缘 / F 中心 The ratio is between 1.4 and 50.0, preferably F. 边缘 / F 中心 The ratio is between 1.5 and 10.0, more preferably F 边缘 / F 中心 The ratio is between 1.55 and 5.0, with F being the most preferred. 边缘 / F 中心 The ratio is between 1.65 and 3.0.

[0039] In a more preferred embodiment, the particles are particles according to the invention, wherein ·Co 边缘 / Co 中心 The ratio is between 1.55 and 50.0, preferably Co. 边缘 / Co 中心 The ratio is between 1.6 and 10.0, more preferably Co. 边缘 / Co 中心 The ratio is between 1.65 and 5.0, with Co being the most preferred. 边缘 / Co 中心The ratio is between 1.7 and 3.0; ·Al 边缘 / Al 中心 The ratio is between 20.0 and 100.0, preferably Al. 边缘 / Al 中心 The ratio is between 30.0 and 75.0, with Al being more preferred. 边缘 / Al 中心 The ratio is between 35.0 and 60.0; and ·F 边缘 / F 中心 The ratio is between 1.4 and 50.0, preferably F. 边缘 / F 中心 The ratio is between 1.5 and 10.0, more preferably F 边缘 / F 中心 The ratio is between 1.55 and 5.0, with F being the most preferred. 边缘 / F 中心 The ratio is between 1.65 and 3.0.

[0040] In a preferred embodiment, the particles are according to the invention, and their Ni 中心 Value ≥ 45.0 at%, where Ni 中心 It is the atomic ratio of Ni to the sum of Ni, Co, and Mn at the center of the particle, where Ni 中心 It was measured using cross-sectional SEM-EDS.

[0041] In a more preferred embodiment, the particles are particles according to the invention, wherein Ni 中心 Value ≥ 50.0 at%, preferably Ni 中心 Value ≥ 55.0 at%, more preferably Ni 中心 Value ≥ 60.0 at%. In a more preferred embodiment, the particles are particles according to the invention, wherein Ni 中心 Value ≤ 75.0 at%, preferably Ni 中心 Value ≤ 70.0 at%, more preferably Ni 中心 Value ≤ 65.0 at%. In a more preferred embodiment, the particles are particles according to the invention, wherein Ni 中心 The value is between 50.0 at% and 75.0 at%, preferably Ni. 中心 Values ​​between 55.0 at% and 70.0 at% are preferred for Ni. 中心 The value is between 60.0 at% and 65.0 at%.

[0042] In a preferred embodiment, the particles are those according to the present invention, wherein Mn 中心Value ≥ 10.0 at%, where Mn 中心 It is the atomic ratio of Mn to the sum of Ni, Co, and Mn at the center of the particle, where Mn 中心 It was measured using cross-sectional SEM-EDS.

[0043] In a more preferred embodiment, the particles are particles according to the invention, wherein Mn 中心 Value ≥ 15.0 at%, preferably Mn 中心 Value ≥ 18.0 at%, more preferably Mn 中心 Value ≥ 20.0 at%. In a more preferred embodiment, the particles are particles according to the invention, wherein Mn 中心 Value ≤ 35.0 at%, preferably Mn 中心 Value ≤ 30.0 at%, more preferably Mn 中心 Value ≤ 25.0 at%. In a more preferred embodiment, the particles are particles according to the invention, wherein Mn 中心 The value is between 15.0 at% and 35.0 at%, preferably Mn. 中心 The value is between 18.0 at% and 30.0 at%, more preferably Mn 中心 The value is between 20.0 at% and 25.0 at%.

[0044] In a preferred embodiment, the particles are particles according to the invention, wherein at least one of the primary particles contains Co. 中心 Value ≥ 5.0 at%, where Co 中心 It is the atomic ratio of Co to the sum of Ni, Co, and Mn at the center of a primary particle, where Co... 中心 It was measured using cross-sectional SEM-EDS.

[0045] In a more preferred embodiment, the particles are particles according to the invention, wherein Co 中心 Value ≥ 10.0 at%, preferably Co 中心 Value ≥ 12.0 at%, more preferably Co 中心 Value ≥ 15.0 at%. In a more preferred embodiment, the particles are particles according to the invention, wherein Co 中心 Value ≤ 30.0 at%, preferably Co 中心 Value ≤ 25.0 at%, more preferably Co 中心 Value ≤ 20.0 at%. In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein Co 中心 The value is between 10.0 at% and 35.0 at%, preferably Co. 中心Values ​​between 18.0 at% and 30.0 at% are preferred, Co. 中心 The value is between 20.0 at% and 25.0 at%.

[0046] In a particular, highly preferred embodiment, the particles are particles according to the invention. Ni 中心 The value is between 50.0 at% and 75.0 at%, preferably Ni. 中心 Values ​​between 55.0 at% and 70.0 at% are preferred for Ni. 中心 The value is between 60.0 at% and 65.0 at%; ·Mn 中心 The value is between 15.0 at% and 35.0 at%, preferably Mn. 中心 The value is between 18.0 at% and 30.0 at%, more preferably Mn 中心 The value is between 20.0 at% and 25.0 at%; and ·Co 中心 The value is between 10.0 at% and 35.0 at%, preferably Co. 中心 Values ​​between 18.0 at% and 30.0 at% are preferred, Co. 中心 The value is between 20.0 at% and 25.0 at%.

[0047] In a particular preferred embodiment, the particles of the present invention are single particles composed of a primary particle.

[0048] In a particular preferred embodiment, the particles of the present invention are secondary particles consisting of at least two primary particles and at most 20 primary particles.

[0049] In the context of this invention, primary particles are distinguished from each other in SEM images by observing the grain boundaries between them. A grain boundary is defined as the interface between two primary particles, preferably wherein the atomic planes of the two primary particles are aligned with different orientations and intersect in a crystalline discontinuous manner. Thus, primary particles constituting single particles and / or secondary particles are observed in SEM images.

[0050] Positive electrode active material In a second aspect, the present invention provides a positive electrode active material comprising particles according to the first aspect of the present invention.

[0051] In a preferred embodiment, the positive electrode active material of the present invention is a powder comprising a plurality of particles according to the present invention, wherein at least one of the particles is a single particle as defined herein and / or a secondary particle as defined herein.

[0052] In a preferred embodiment, the positive electrode active material is a positive electrode active material according to the present invention, wherein the Ni atom content of the positive electrode active material is at least 45.0 at%, preferably at least 50.0 at%, more preferably at least 55.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment is a positive electrode active material of the present invention, wherein the Ni atom content of the positive electrode active material is at most 95.0 at%, preferably at most 90.0 at%, more preferably at most 85.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment is a positive electrode active material of the present invention, wherein the Ni atom content of the positive electrode active material is from 45.0 at% to 95.0 at%, preferably from 50.0 at% to 90.0 at%, more preferably from 55.0 at% to 85.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES.

[0053] A specific preferred embodiment of the present invention is a cathode active material in which the Ni atom content relative to the total amount of Ni, Co and Mn is 45.0 at% to 75.0 at%, preferably 50.0 at% to 70.0 at%, more preferably 55.0 at% to 65.0 at%, as determined by ICP-OES.

[0054] A preferred embodiment of the cathode active material according to the present invention has a Co atom content of at least 3.0 at%, preferably at least 5.0 at%, and more preferably at least 10.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment of the cathode active material according to the present invention has a Co atom content of up to 30.0 at%, preferably up to 25.0 at%, and more preferably up to 22.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment of the cathode active material according to the present invention has a Co atom content of 3.0 at% to 30.0 at%, preferably 5.0 at% to 25.0 at%, and more preferably 10.0 at% to 22.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES.

[0055] A preferred embodiment of the cathode active material according to the present invention has a Mn atomic content of at least 3.0 at%, preferably at least 5.0 at%, and more preferably at least 10.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment of the cathode active material according to the present invention has a Mn atomic content of at most 35.0 at% or at most 30.0 at%, preferably at most 25.0 at%, and more preferably at most 20.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES. A preferred embodiment of the cathode active material according to the present invention has a Mn atomic content of 3.0 at% to 30.0 at%, preferably 5.0 at% to 25.0 at%, and more preferably 10.0 at% to 20.0 at%, relative to the total amount of Ni, Co, and Mn, as determined by ICP-OES.

[0056] A preferred embodiment of the positive electrode active material according to the present invention has an Al atomic content of 0.3 at% to 3.0 at% relative to the total amount of Ni, Co and Mn, preferably 0.4 at% to 2.0 at%, more preferably 0.6 at% to 1.0 at%, as determined by ICP-OES.

[0057] A preferred embodiment of the positive electrode active material of the present invention has a Li / (Ni+Mn+Co) ratio (mol / mol) > 0.90, preferably > 0.92, and more preferably > 0.95. A preferred embodiment of the positive electrode active material of the present invention has a Li / (Ni+Mn+Co) ratio (mol / mol) < 1.10, preferably < 1.08, and more preferably < 1.05. A preferred embodiment of the positive electrode active material of the present invention has a Li / (Ni+Mn+Co) ratio (mol / mol) in the range of 0.90-1.10, preferably in the range of 0.92-1.08, and more preferably in the range of 0.95-1.05.

[0058] A more preferred embodiment is the positive electrode active material of the present invention. - The Ni atom content of the positive electrode active material is 45.0 at% to 95.0 at%, preferably 50.0 at% to 90.0 at%, more preferably 55.0 at% to 85.0 at%, as determined by ICP-OES, relative to the total amount of Ni, Co and Mn; - The Co atom content of the positive electrode active material is 3.0 at% to 30.0 at% relative to the total amount of Ni, Co and Mn, preferably 5.0 at% to 25.0 at%, more preferably 10.0 at% to 22.0 at%, as determined by ICP-OES; - The Mn atomic content of the positive electrode active material relative to the total amount of Ni, Co, and Mn is 3.0 at% to 35.0 at% or 3.0 at% to 30.0 at%, preferably 5.0 at% to 25.0 at%, more preferably 10.0 at% to 20.0 at%, as determined by ICP-OES; and - The Al atom content of the positive electrode active material is 0.3 at% to 3.0 at% relative to the total amount of Ni, Co and Mn, preferably 0.4 at% to 2.0 at%, more preferably 0.6 at% to 1.0 at%, as determined by ICP-OES.

[0059] Even more preferred embodiments are the positive electrode active materials of the present invention. - The Ni atom content of the positive electrode active material is 45.0 at% to 75.0 at%, preferably 50.0 at% to 70.0 at%, more preferably 55.0 at% to 65.0 at%, as determined by ICP-OES, relative to the total amount of Ni, Co and Mn; - The Co atom content of the positive electrode active material is 3.0 at% to 30.0 at% relative to the total amount of Ni, Co and Mn, preferably 5.0 at% to 25.0 at%, more preferably 10.0 at% to 22.0 at%, as determined by ICP-OES; - The Mn atomic content of the positive electrode active material relative to the total amount of Ni, Co, and Mn is 3.0 at% to 35.0 at% or 3.0 at% to 30.0 at%, preferably 5.0 at% to 25.0 at%, more preferably 10.0 at% to 20.0 at%, as determined by ICP-OES; and - The Al atom content of the positive electrode active material is 0.3 at% to 3.0 at% relative to the total amount of Ni, Co and Mn, preferably 0.4 at% to 2.0 at%, more preferably 0.6 at% to 1.0 at%, as determined by ICP-OES.

[0060] A specific preferred embodiment is the positive electrode active material of the present invention comprising Li, M', F and oxygen, wherein M' comprises: - Ni with a content of x, wherein relative to M', 45.0 at% ≤ x ≤ 95.0 at%, preferably wherein relative to M', 50.0 at% ≤ x ≤ 90.0 at%, more preferably relative to M', 55.0 at% ≤ x ≤ 85.0 at%; - Mn with a content of y, wherein relative to M', 3.0 at% ≤ y ≤ 35.0 at%, or wherein 3.0 at% ≤ y ≤ 30.0 at%, preferably wherein 5.0 at% ≤ y ≤ 25.0 at%, more preferably wherein 10.0 at% ≤ y ≤ 20.0 at%; - Co with a content of z, wherein relative to M', 3.0 at% ≤ z ≤ 30.0 at%, preferably wherein 5.0 at% ≤ z ≤ 25.0 at%, more preferably wherein 10.0 at% ≤ z ≤ 22.0 at%; - Al with a content of a, wherein relative to M', 0.3 at% ≤ a ≤ 3.0 at%, preferably wherein relative to M', 0.4 at% ≤ a ≤ 2.0 at%, more preferably wherein 0.6 at% ≤ a ≤ 1.0 at%; - D with a content of d, wherein relative to M', 0.0 at% ≤ d ≤ 2.0 at%, where D is an element different from Li, Ni, Mn, Co, Al, F and oxygen; -- Where x, y, z, a, b, and d are measured by ICP-OES, and -- where x+y+z+a+d is 100.0 at.

[0061] A more specific preferred embodiment is the positive electrode active material of the present invention comprising Li, M', F and oxygen, wherein M' comprises: - Ni content of x, wherein relative to M', 45.0 at% ≤ x ≤ 75.0 at%, preferably wherein relative to M', 50.0 at% ≤ x ≤ 70.0 at%, more preferably relative to M', 55.0 at% ≤ x ≤ 65.0 at%; - Mn with a content of y, wherein relative to M', 3.0 at% ≤ y ≤ 35.0 at%, or wherein 3.0 at% ≤ y ≤ 30.0 at%, preferably wherein 5.0 at% ≤ y ≤ 25.0 at%, more preferably wherein 10.0 at% ≤ y ≤ 20.0 at%; - Co with a content of z, where 3.0 at% ≤ z ≤ 30.0 at% relative to M', preferably 5.0 at% ≤ z ≤ 25.0 at%, more preferably 10.0 at% ≤ z ≤ 22.0 at%; - Al with a content of a, where 0.3 at% ≤ a ≤ 3.0 at% relative to M', preferably 0.4 at% ≤ a ≤ 2.0 at% relative to M', more preferably 0.5 at% ≤ a ≤ 2.0 at%; - D with a content of d, where 0.0 at% ≤ d ≤ 2.0 at% relative to M', where D is an element different from Li, Ni, Mn, Co, Al, F, and oxygen; - where x, y, z, a, b, and d are measured by ICP - OES, and - where x + y + z + a + d is 100.0 at%.

[0062] As known to those skilled in the art, the positive electrode active material of the present invention may contain impurities or be doped with or contain metals on the surface, such that the entire positive electrode active material contains one or more elements other than Li, Ni, Mn, Co, F, and O, which is reflected in the parameter "D" used herein. A preferred embodiment is the positive electrode active material according to the present invention containing D, where D is at least one element selected from the group consisting of: B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Sr, Ti, V, W, Y, Zn, and Zr; preferably Ti, Cr, Nb, S, Y, W, and Zr; more preferably Ti, Nb, W, and Zr.

[0063] In a preferred embodiment, relative to M', the content d is 0.0 at% < d ≤ 1.75 at%, preferably 0.25 at% ≤ d ≤ 1.5 at%, more preferably 0.5 at% ≤ d ≤ 1.25 at%.

[0064] In a specific preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, where relative to M', d = 0.0 at%.

[0065] In a specific preferred embodiment, the positive electrode active material consists of Li, M', F, and oxygen.

[0066] In a highly preferred embodiment, the positive electrode active material contains F and a lithium transition metal oxide according to formula (I): Li w2 Ni x2 Mn y2 Coz2 Al a2 D2 d2 O2(I) where 0.90 ≤ w2 ≤ 1.10, preferably 0.92 ≤ w2 ≤ 1.08, more preferably 0.95 ≤ w2 ≤ 1.05; where 0.45 ≤ x2 ≤ 0.75, preferably 0.50 ≤ x2 ≤ 0.70, more preferably 0.55 ≤ x2 ≤ 0.65; where 0.03 < y2 ≤ 0.35 or 0.03 < y2 ≤ 0.30, preferably 0.05 < y2 ≤ 0.25, more preferably 0.10 ≤ y2 ≤ 0.20; where 0.03 < z2 ≤ 0.30, preferably 0.05 < z2 ≤ 0.25, more preferably 0.10 ≤ z2 ≤ 0.22; where 0.003 < a2 ≤ 0.03, preferably 0.004 ≤ a2 ≤ 0.02, more preferably 0.006 ≤ a2 ≤ 0.01; where 0.0 ≤ d2 ≤ 0.02, preferably 0.0 ≤ d2 ≤ 0.001, more preferably d2 is about 0.0; and where x2 + y2 + z2 + a2 + d2 = 1.0.

[0067] As known to those skilled in the art, the positive electrode active material of the present invention may contain impurities or be doped with or contain metals on the surface, so that the entire positive electrode active material contains one or more elements other than Li, Ni, Mn, Co, Al and O, which is reflected in the parameter "D2" used herein. A preferred embodiment is the positive electrode active material according to the present invention containing D2, where D2 is at least one element selected from the group consisting of: B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Sr, Ti, V, W, Y, Zn and Zr; preferably Ti, Cr, Y, W and Zr; more preferably Ti, W and Zr. In a specific preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, where b2 = 0.0 relative to M2.

[0068] As understood by those skilled in the art, the amounts of Li, Ni, Mn, Co, Al and D in the positive electrode active material are measured by inductively coupled plasma optical emission spectrometry (ICP - OES). For example, but not limiting the present invention, an Agilent ICP 720 - ES is used in the ICP - OES analysis.

[0069] In a preferred embodiment, the positive electrode active material is a positive electrode active material according to the present invention, wherein the positive electrode active material comprises aluminum, and the atomic ratio of Al to the total amount of Ni, Co and Mn is 1.0 to 7.0, as determined by XPS analysis.

[0070] In a preferred embodiment, the atomic ratio of Al to the total amount of Ni, Co and Mn is 1.5 to 6.0, preferably 2 to 5, more preferably 2.5 to 3.0, as determined by XPS analysis.

[0071] In a highly preferred embodiment, the positive electrode active material of the present invention comprises cobalt, and the atomic ratio of Co to the total amount of Ni, Co and Mn is 0.25 to 0.45, as determined by XPS analysis.

[0072] Therefore, in a highly preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein the positive electrode active material comprises: - Aluminum, and the atomic ratio of Al to the total amount of Ni, Co and Mn is 1.0 to 7.0, as determined by XPS analysis, and - Cobalt, and the atomic ratio of Co to the total amount of Ni, Co and Mn is 0.25 to 0.45, as determined by XPS analysis.

[0073] In a more preferred embodiment, the atomic ratio of Co to the total amount of Ni, Co and Mn in the positive electrode active material of the present invention is 0.30 to 0.44, preferably 0.32 to 0.42, as determined by XPS analysis.

[0074] In a preferred embodiment, the Co of the positive electrode active material of the present invention XPS / Co ICP The ratio is 1.50 to 2.30, of which Co XPS This refers to the atomic ratio of Co to the total amounts of Ni, Co, and Mn, ranging from 0.25 to 0.45, as determined by XPS analysis; and Co ICP It is the atomic ratio of Co to the total amount of Ni, Co and Mn, which is 0.25 to 0.45 as determined by ICP-OES.

[0075] Therefore, in a particular highly preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein the positive electrode active material comprises: - Aluminum, and the atomic ratio of Al to the total amount of Ni, Co and Mn is 1.0 to 7.0, as determined by XPS analysis. -Co XPS / Co ICP The ratio is 1.50 to 2.30, of which Co XPSThis refers to the atomic ratio of Co to the total amounts of Ni, Co, and Mn, ranging from 0.25 to 0.45, as determined by XPS analysis; and Co ICP It is the atomic ratio of Co to the total amount of Ni, Co and Mn, which is 0.25 to 0.45 as determined by ICP-OES.

[0076] Therefore, in a particular highly preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein the positive electrode active material comprises: - Aluminum, and the atomic ratio of Al to the total amount of Ni, Co and Mn is 1.0 to 7.0, as determined by XPS analysis; - Cobalt, and the atomic ratio of Co to the total amount of Ni, Co and Mn is 0.25 to 0.45, as determined by XPS analysis; and -Co XPS / Co ICP The ratio is 1.50 to 2.30, of which Co XPS This refers to the atomic ratio of Co to the total amounts of Ni, Co, and Mn, ranging from 0.25 to 0.45, as determined by XPS analysis; and Co ICP It is the atomic ratio of Co to the total amount of Ni, Co and Mn, which is 0.25 to 0.45 as determined by ICP-OES.

[0077] In a more preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein Co XPS / Co ICP The ratio is 1.60 to 2.25, preferably 1.70 to 2.20, and more preferably 1.75 to 2.15.

[0078] In a preferred embodiment, the positive electrode active material is a positive electrode active material according to the present invention, which further comprises F, and the atomic ratio of F to the total amount of Ni, Co and Mn is 0.5 to 6.0, as determined by XPS analysis.

[0079] In a preferred embodiment, the positive electrode active material is the positive electrode active material according to the present invention, wherein the atomic ratio of F to the total amount of Ni, Co and Mn is 1.0 to 5.0, preferably 1.5 to 4.0, more preferably 1.8 to 3.0, as determined by XPS analysis.

[0080] In a particular preferred embodiment, the present invention provides a positive electrode active material according to the present invention, wherein the positive electrode active material is a powder comprising the single particles and / or the secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in SEM images.

[0081] Preferably, at least 30% of the particles constituting the powder observed in the SEM image, more preferably at least 50%, are single particles and / or secondary particles. The number of primary particles constituting the single particles and / or secondary particles is determined in a field of view of at least 45 μm × at least 60 μm (i.e., at least 2700 μm²), preferably at least 100 μm × 100 μm (i.e., at least 10,000 μm²).

[0082] The particles in the image should be well-distributed, thus avoiding overlap between particles. This can be achieved by pouring a small amount of powder sample onto the adhesive attached to the SEM sample holder and blowing air to remove excess powder.

[0083] In the context of this invention, primary particles are distinguished from each other in SEM images by observing the grain boundaries between them. A grain boundary is defined as the interface between two primary particles, preferably wherein the atomic planes of the two primary particles are aligned with different orientations and intersect in a crystalline discontinuous manner.

[0084] Specific preferred embodiments relate to the positive electrode active material of the present invention, which is the powder comprising single particles and / or secondary particles. The median particle size D50 value of the powder is less than 15 μm, preferably less than 10 μm, and more preferably less than 8 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the median particle size D50 value of the powder is greater than 1 μm, preferably greater than 2 μm, and more preferably greater than 4 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the median particle size D50 value of the powder is between 1 μm and 15 μm, preferably between 2 μm and 10 μm, and more preferably between 4 μm and 8 μm.

[0085] As understood by those skilled in the art, the particle size distribution (PSD) D50 of the positive electrode active material powder is measured by laser diffraction particle size analysis. Preferably, D50 is defined as the volume median particle size, more preferably as the particle size at 50% of the cumulative volume % distribution obtained from a Malvern Mastersizer 3000 with Hydro MV measurement. For example, but not limiting the invention, the particle median D50 can be measured using a Malvern Mastersizer 3000.

[0086] Battery In a third aspect, the present invention relates to a battery comprising a positive electrode active material according to a second aspect of the present invention.

[0087] In a preferred embodiment, the battery is a solid-state battery.

[0088] In a preferred embodiment, the solid-state battery comprises a polymer-based electrolyte, preferably a polymer-based solid electrolyte, more preferably a polymer comprising ethylene oxide units, and most preferably a polymer-based solid electrolyte is polyethylene oxide. The invention is not limited to a specific polyethylene oxide having a particular weight-average molecular weight Mw. Many such polymers having different number-average molecular weights are commercially available. Preferably, the polyethylene oxide has a weight-average molecular weight Mw of less than 5,000,000 g / mol and greater than 50,000 g / mol, preferably less than 3,000,000 g / mol and greater than 100,000 g / mol, more preferably less than 2,000,000 g / mol and greater than 500,000 g / mol, and most preferably about 1,000,000 g / mol.

[0089] In a highly preferred embodiment, the battery is a polymer solid-state battery.

[0090] Preferably, the solid-state battery further includes an anode comprising an anode active material. Suitable electrochemically active anode materials are those known in the art. For example, the anode may comprise graphite carbon, metallic lithium, or lithium-containing metal alloys such as Li-In alloys as the anode active material.

[0091] In a preferred embodiment, the DCR2-DCR1 value of the battery according to the invention is less than 400 Ω, preferably less than 300 Ω, more preferably less than 200 Ω, and most preferably less than 150 Ω. As those skilled in the art will understand, the DCR1 and DCR2 values ​​are determined as explained in point E2 of the example described below.

[0092] use In a fourth aspect, the present invention relates to the use of a positive electrode active material according to a second aspect of the present invention in a battery.

[0093] A preferred embodiment is the use of a positive electrode active material in a battery, preferably a solid-state battery, more preferably a polymer solid-state battery, to reduce the DCR value of the battery.

[0094] In a fifth aspect, the present invention relates to the use of the battery according to the invention in any of portable computers, tablet computers, mobile phones, energy storage systems, electric vehicles or hybrid electric vehicles, preferably in electric vehicles or hybrid electric vehicles.

[0095] Example Experimental tests used in the examples The following analysis methods were used in the example: A) Inductively Coupled Plasma-Optical Emission Analysis (ICP-OES) The elemental contents of the positive electrode active materials examples and comparative examples described below were measured using an Agilent ICP 720-OES instrument via inductively coupled plasma-optical emission spectrometry (ICP-OES). One gram of powder sample was dissolved in 50 mL of high-purity hydrochloric acid in a conical flask. The flask was covered with a watch glass and heated on a hot plate at 380°C until the sample was completely dissolved. After cooling to room temperature, the solution and rinsing water from the conical flask were transferred to a 250 mL volumetric flask. The volumetric flask was then filled to the 250 mL mark with DI water and thoroughly homogenized. A second dilution was performed by pipetting an appropriate amount of solution and transferring it to a 250 mL volumetric flask, which was then filled to the 250 mL mark with an internal standard and 10% hydrochloric acid and homogenized. Finally, this solution was used for ICP-OES measurements. The contents of Ni, Mn, Co, and Al are expressed as wt.% of the total of these contents.

[0096] B) Particle size After dispersing the positive electrode active material powder examples as described below in an aqueous medium, the PSD was measured using a Malvern Mastersizer 3000 with a Hydro MV wet dispersion attachment. To improve the dispersion of the positive electrode active material powder examples, adequate ultrasonic irradiation and stirring were applied, and a suitable surfactant was introduced. D50 was defined as the particle size at 50% of the cumulative volume percentage distribution.

[0097] C) X-ray photoelectron spectroscopy (XPS) In this invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of positive electrode active material powder particles. In XPS measurements, the signal is obtained from the top few nanometers (e.g., 1 nm to 10 nm) of the sample (i.e., the surface layer). Therefore, all elements measured by XPS are contained within the surface layer.

[0098] For surface analysis of the positive electrode active material powder particles, XPS measurements were performed using a Thermo K-α+ spectrometer. Monochromatic Al Kα radiation (hυ = 1486.6 eV) was used with a spot size of 400 mm and a measurement angle of 45°. A wide probe scan at a pass energy of 200 eV was performed to identify elements present at the surface. After data collection, the C1s peak with the maximum intensity (or intermediate) at a binding energy of 284.8 eV was used as the calibration peak position. Subsequently, a precise narrow scan at 50 eV was performed, with at least 10 scans for each identified element to determine the precise surface composition.

[0099] Curve fitting was performed using Shirley-type background processing and a Scofield sensitivity factor with CasaXPS version 2.3.19PR1.0. Fitting parameters are shown in Table 1a. The linearity GL(30) is a Gaussian / Lorentz product formula with a 70% Gaussian line and a 30% Lorentz line.

[0100] Table 1a. XPS fitting parameters for Ni2p3, Mn2p3, Co2p3, Al2p3 and F1s.

[0101]

[0102] For the Al, Ni, Co, and Mn peaks, constraints are set for each defined peak according to Table 1b.

[0103] Table 1b. XPS fitting constraints for Al, Ni, Co and Mn peak fitting.

[0104]

[0105]

[0106] The surface content of Al and F determined by XPS is expressed as the atomic fraction of Al and F in the surface layer of the particle divided by the total content of Ni, Mn and Co in the surface layer.

[0107] D) Cross-sectional energy-dispersive X-ray spectroscopy (CS-EDS) D1) Cross-section preparation The cross-sections of the positive electrode active materials described below, as well as the comparative examples, were prepared using an ion beam cross-section polishing (CP) instrument, JEOL (IB-19530CP). The instrument used argon as the beam source.

[0108] To prepare the sample, a small amount of positive electrode active material powder was mixed with resin and hardener, and then the mixture was heated on a hot plate for 10 minutes. After heating, it was placed in an ion beam instrument for cutting and the settings were adjusted according to standard procedures, with a voltage of 6.5 kV for 3 hours.

[0109] D2) Energy-dispersive X-ray spectroscopy (EDS) analysis Using samples of positive electrode active materials prepared according to method D) above, the concentrations of Ni, Mn, Co, Al, and F from the edge to the center of the positive electrode active material particles were analyzed by energy-dispersive X-ray spectroscopy (EDS). For each sample, particles with a diameter of approximately D50, measured by PSD according to part B), were selected for analysis. The EDS was performed using 50 mm EDS units from Oxford Instruments. 2The X-MaxN EDS sensor was used with a JEOL JSM 7100F SEM instrument. EDS analysis of the positive electrode active material particles provided a quantitative elemental analysis of the cross-section, assuming the particles were spherical. A straight line was established from the edge of the particle to the center point, and the concentrations of Ni, Mn, Co, Al, and F were measured at both the edge and the center, and expressed as at% relative to the sum of the Ni, Mn, and Co contents at each point.

[0110] E) Polymer battery testing E1) Polymer Battery Fabrication E1.1) Preparation of Solid Polymer Electrolytes (SPE) Solid polymer electrolytes (SPEs) are prepared according to the following method: Step 1) Using a mixer, mix polyethylene oxide (PEO, 1,000,000 g / mol, Alfa Aesar) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, >98.0%, TCI) in 99.8 wt% anhydrous acetonitrile (Aldrich) for 30 minutes at 2,000 rpm. The mass ratio of polyethylene oxide to LiTFSI is 3.0.

[0111] Step 2) Pour the mixture from Step 1) into a Teflon tray and dry at 25°C for 12 hours.

[0112] Step 3) Separate the dried SPE from the disc and punch the dried SPE to obtain an SPE disc with a thickness of 300 μm and a diameter of 19 mm.

[0113] E1.2) Positive electrode preparation The positive electrode is prepared according to the following method: Step 1) Prepare a polymer electrolyte mixture comprising a solution of polyethylene oxide (PEO, 100,000 g / mol, Alfa Aesa) in 99.7 wt% anhydrous anisole (Sigma-Aldrich) and an acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, >98.0%, TCI). The weight ratio of PEO to LiTFSI in the mixture is 74:26.

[0114] Step 2) The polymer electrolyte mixture prepared in Step 1) is mixed with the positive electrode active material and conductor powder (Super P, Timcal) in an acetonitrile solution at a weight ratio of 21:75:4 to prepare a slurry mixture. The mixing is carried out in a homogenizer at 5,000 rpm for 45 minutes.

[0115] Step 3) Pour the slurry mixture from Step 2) onto one side of a 20 μm thick aluminum foil with a 100 μm coating gap.

[0116] Step 4) Dry the foil cast with slurry at 30°C for 12 hours, and then punch it to obtain a cathode electrolyte electrode with a diameter of 14 mm.

[0117] E1.3) Anode Preparation A Li foil (16 mm in diameter and 500 µm in thickness) was prepared as the negative electrode.

[0118] E1.4) Polymer battery assembly The coin-type polymer battery is assembled in an argon-filled glove box in the following order from bottom to top: 2032 coin battery canister, positive electrode prepared according to Section C1.2, SPE prepared according to Section C1.1, gasket, negative electrode prepared according to Section C1.3, spacer, wave spring, and battery cap. The coin battery is then completely sealed to prevent electrolyte leakage.

[0119] E2) Test Method Each battery cell was cycled at 80°C using a Toscat-3100 computer-controlled constant current cycling station (Toyo). The coin cell test procedure was defined using a 1C current of 160 mA / g within the 4.4–3.0 V / Li metal window, according to the following scheme: Step 1) Charge in constant current mode at a rate of 0.05 C, end at 4.4 V, and then let stand for 10 minutes.

[0120] Step 2) Discharge in constant current mode with a C rate of 0.05 and an end condition of 3.0 V, then let it stand for 10 minutes.

[0121] Step 3) Charge to 50% SOC in constant current mode at a C rate of 0.05, and measure DCR at a pulse current of 0.15C and a pulse length of 10 seconds to obtain DCR1.

[0122] DCR is calculated using the following equation: DCR = (V before pulse - V after pulse) / applied pulse current After DCR measurement, continue charging until the termination condition is 4.4 V.

[0123] Step 4) Switch to constant voltage mode and maintain 4.4 V for 60 hours.

[0124] Step 5) Discharge in constant current mode with a C rate of 0.05 and a termination condition of 3.0 V.

[0125] 6) Repeat step 3 to obtain DCR2.

[0126] The present invention is further illustrated in the following examples: Comparison Example 1 A cathode active material powder labeled CEX1 was obtained through a solid-state reaction between a lithium source and a nickel-based transition metal source. The process proceeded as follows: Step 1) Precursor preparation: Ni with metallic composition was prepared by a co-precipitation process in a large continuous stirred tank reactor (CSTR) using a mixture of nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. 0.63 Mn 0.22 Co 0.15 Hydroxide powders of transition metal oxidation.

[0127] Step 2) First mixing: The precursor prepared according to step 1) is mixed with Li2CO3 in an industrial mixer to obtain a first mixture with a lithium metal ratio of 0.85.

[0128] Step 3) First firing: The first mixture from Step 2) is fired at 900°C for 10 hours in a dry air atmosphere to obtain a first fired block. The first fired block is ground to obtain a first fired powder.

[0129] Step 4) Second mixing: The first calcined powder from step 3) is mixed with LiOH in an industrial mixer to obtain a second mixture with a lithium metal ratio of 1.05.

[0130] Step 5) Second firing: The second mixture from step 4) is fired in dry air at 930°C for 10 hours, followed by crushing (bead milling) and sieving to obtain the second fired powder.

[0131] Step 6) Third mixing: The second calcined powder from step 5) is mixed in an industrial mixer with 2 mol% Co from Co3O4 powder and 5 mol% LiOH relative to the total molar content of Ni, Mn and Co to obtain a third mixture.

[0132] Step 7) Third Firing: The third mixture from Step 6) was fired in dry air at 775°C for 12 hours to produce a third-fired powder labeled CEX1. The powder has a D50 of 6.4 µm, as determined by laser diffraction. CEX1 comprises single particles and secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in the SEM images.

[0133] Comparison Example 2 The positive electrode active material CEX2 was prepared according to the following process: Step 1) Mix 1 kg of CEX1 powder with 2 g of alumina (Al2O3) nanopowder at 1000 rpm for 30 minutes.

[0134] Step 2) The mixture obtained in Step 1) is fired in a furnace at 750°C for 10 hours under an oxidizing atmosphere.

[0135] Step 3) Mix 1 kg of powder from Step 2) with 2 g of alumina (Al2O3) nanoparticles and 3 g of polyvinylidene fluoride (PVDF) powder at 1000 rpm for 30 minutes.

[0136] Step 4) The mixture obtained in Step 3) was calcined in a furnace at 375°C for 5 hours under an oxidizing atmosphere to produce a calcined powder labeled CEX2. The powder has a D50 of 6.4 µm, as determined by laser diffraction. CEX2 comprises single particles and secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in the SEM images.

[0137] Comparison Example 3 The positive electrode active material CEX3 was prepared according to the following process: Step 1) CEX1 is mixed in an industrial mixer with 1 mol% Co from Co3O4 powder and 5 mol% LiOH relative to the total molar content of Ni, Mn and Co to obtain a mixture.

[0138] Step 2) Firing: The mixture from Step 1) was calcined in dry air at 750°C for 12 hours to produce a calcined powder labeled CEX3. The powder has a D50 of 6.4 µm, as determined by laser diffraction. CEX3 comprises single particles and secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in the SEM images.

[0139] Comparison Example 4 The positive electrode active material CEX4 was prepared according to the following process: Step 1) CEX1 is mixed in an industrial mixer with 2 mol% Co from Co3O4 powder and 5 mol% LiOH relative to the total molar content of Ni, Mn and Co to obtain a mixture.

[0140] Step 2) Firing: The mixture from Step 1) was calcined in dry air at 750°C for 12 hours to produce a calcined powder labeled CEX4. The powder has a D50 of 6.4 µm, as determined by laser diffraction. CEX4 comprises single particles and secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in the SEM images.

[0141] Comparison Example 5 The positive electrode active material CEX5 was prepared according to the following process: Step 1) CEX1 is mixed in an industrial mixer with Co from Co3O4 powder at a total molar content of 3 mol% relative to Ni, Mn and Co and 5 mol% of LiOH to obtain a mixture.

[0142] Step 2) Firing: The mixture from Step 1) was calcined in dry air at 750°C for 12 hours to produce a calcined powder labeled CEX5. The powder has a D50 of 6.4 µm, as determined by laser diffraction. CEX5 comprises single particles and secondary particles, wherein each single particle consists of only one primary particle, and each secondary particle consists of at least two and at most twenty primary particles, as observed in the SEM images.

[0143] Comparison Example 6 The positive electrode active material CEX6 was prepared using the same method as CEX2, except that CEX5 was used instead of CEX1 in step 1). The D50 of the powder was 6.4 µm, as determined by laser diffraction. CEX6 comprised single particles and secondary particles, wherein each single particle consisted of only one primary particle, and each secondary particle consisted of at least two and at most twenty primary particles, as observed in the SEM images.

[0144] Example 1 The positive electrode active material EX1 was prepared using the same method as CEX2, except that CEX3 was used instead of CEX1 in step 1). The D50 of the powder was 6.4 µm, as determined by laser diffraction. EX1 comprised single particles and secondary particles, wherein each single particle consisted of only one primary particle, and each secondary particle consisted of at least two and at most twenty primary particles, as observed in the SEM images.

[0145] Example 2 The positive electrode active material EX2 was prepared using the same method as CEX2, except that CEX4 was used instead of CEX1 in step 1). The D50 of the powder was 6.2 µm, as determined by laser diffraction. EX2 comprised single particles and secondary particles, wherein each single particle consisted of only one primary particle, and each secondary particle consisted of at least two and at most twenty primary particles, as observed in the SEM images.

[0146] result Table 2. Overview of SEM-EDS analysis of the examples and comparative examples.

[0147]

[0148] Table 3. Overview of the characteristics of the instance and comparison instance.

[0149]

[0150]

[0151] Table 2 summarizes the cross-sectional SEM-EDS analyses of the examples and comparative examples, where major variations exist in elemental concentrations, particularly for Co, Al, and F. Edge / center values ​​above 1 indicate that the element is more enriched on the surface than at the center, and the higher the value, the more enriched the element.

[0152] Table 3 summarizes the characteristics of the examples and comparative examples. The composition measured by ICP-OES indicates the content throughout the particles. On the other hand, in XPS analysis, an Al or F value higher than 0 indicates the presence of Al or F on the surface of the positive electrode active material. This is associated with XPS measurements, whose signals are obtained from the first few nanometers (e.g., 1 nm to 10 nm) of the topmost (i.e., surface layer) of the sample. Battery performance was measured by DCR (DC internal resistance) analysis. This provides information about the internal state of the battery, and the smaller the known value, the better the performance.

[0153] EX1 and EX2 are positive electrode active materials, which have higher Co content than the comparative examples. 边缘 / Co 中心 Values. As confirmed by XPS, the EXs have surfaces enriched in both Al and / or F. Compared to other CEXs, they exhibit improved electrochemical properties, as indicated by lower DCR1 and DCR2 values.

Claims

1. A particle for a positive electrode active material, said positive electrode active material comprising lithium, nickel, cobalt, aluminum, oxygen, and manganese, wherein the Co content of said particle is... 边缘 / Co 中心 The ratio is ≥ 1.1, and Al 边缘 / Al 中心 The ratio is ≥ 20.0, of which Co 边缘 It is the atomic ratio of Co to the total amount of Ni, Co, and Mn at the edge of the particle. Co 中心 It is the atomic ratio of Co to the total amount of Ni, Co, and Mn at the center of the particle. Al 边缘 It is the atomic ratio of Al to the total amount of Ni, Co, and Mn at the edge of the particle. Al 中心 It is the atomic ratio of the total amount of Al to Ni, Co, and Mn at the center of the particle, and Co 边缘 Co 中心 Al 边缘 And Al 中心 It was measured using cross-sectional SEM-EDS.

2. The particles according to claim 1, having a layered α-NaFeO2 structure, a cubic structure, a spinel structure or a combination thereof, preferably a layered α-NaFeO2 structure.

3. The particles according to claim 1 or 2, wherein the Al 边缘 / Al 中心 The ratio is ≥ 30.0, preferably the Al. 边缘 / Al 中心 A ratio ≥ 35.0, more preferably the Al 边缘 / Al 中心 Ratio ≥ 40.

0.

4. The particles according to any one of the preceding claims, wherein the Co 边缘 / Co 中心 The ratio is ≥ 1.2, preferably the Co. 边缘 / Co 中心 The ratio is ≥ 1.3, more preferably the Co. 边缘 / Co 中心 Ratio ≥ 1.

4.

5. The particles according to claim 6, wherein the Co 边缘 / Co 中心 The ratio is ≥ 1.5, preferably the Co. 边缘 / Co 中心 The ratio is ≥ 1.6, more preferably the Co. 边缘 / Co 中心 Ratio ≥ 1.

7.

6. The particles according to any one of the preceding claims, wherein F 边缘 / F 中心 Ratio ≥ 1.1, Where F 边缘 It is the atomic ratio of F to the total amount of Ni, Co, and Mn at the edge of the particle, F 中心 It is the atomic ratio of F to the total amount of Ni, Co, and Mn at the center of the particle. Where F 边缘 and F 中心 It was measured using cross-sectional SEM-EDS.

7. The particles according to claim 8, wherein the F 边缘 / F 中心 The ratio is ≥ 1.2, more preferably the F. 边缘 / F 中心 The ratio is ≥ 1.4, more preferably the F. 边缘 / F 中心 Ratio ≥ 1.

6.

8. The particles according to any one of the preceding claims, wherein the Ni 中心 The value is between 50.0 at% and 75.0 at%, preferably between 55.0 at% and 70.0 at%, and more preferably between 60.0 at% and 65.0 at%. Ni 中心 It is the atomic ratio of Ni to the sum of Ni, Co, and Mn at the center of the particle, and wherein Ni 中心 It was measured using cross-sectional SEM-EDS.

9. The particles according to any one of the preceding claims, wherein the Mn 中心 The value is between 15.0 at% and 35.0 at%, preferably between 18.0 at% and 30.0 at%, and more preferably between 20.0 at% and 25.0 at%. Where Mn 中心 It is the atomic ratio of Ni to the sum of Ni, Co, and Mn at the center of the particle, where Mn 中心 It was measured using cross-sectional SEM-EDS.

10. The particles according to any one of the preceding claims, wherein the Co 中心 The value is between 10.0 at% and 35.0 at%, preferably between 18.0 at% and 30.0 at%, and more preferably between 20.0 at% and 25.0 at%. Co 中心 It is the atomic ratio of Ni to the sum of Ni, Co, and Mn at the center of a primary particle, where Co... 中心 It was measured using cross-sectional SEM-EDS.

11. The particle according to any one of the preceding claims is a single particle composed of a primary particle.

12. The particle according to any one of claims 1 to 10, wherein it is a secondary particle consisting of at least two primary particles and at most 20 primary particles.

13. A positive electrode active material comprising particles according to any one of claims 1 to 12.

14. The positive electrode active material according to claim 13, wherein it is a powder comprising a plurality of said particles.

15. A battery comprising the positive electrode active material according to claim 13 or 14.

Images