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

Abstract

The present invention relates to a positive electrode active material comprising lithium, oxygen, nickel, and at least one metal selected from the group consisting of manganese and cobalt, comprising: Ni in an amount x'with 40.0 < = x '< = 98.0 mol% with respect to the sum of Ni, Mn, and Co; mn in an amount y'with 0.0 < = y '< = 30.0 mol% with respect to the sum of Ni, Mn and Co; and Co in an amount of z ', where 0.0 < = z' < = 30.0 mol%, with respect to the sum of Ni, Mn, and Co, in which the positive electrode active material has enriched amounts of silicon and boron in the surface layer. The electrochemical properties of the positive active material battery, such as first discharge capacity and cycle efficiency.

Description

Technical Field

[0001] This invention relates to a positive electrode active material comprising lithium, oxygen, nickel, boron, and silicon, particularly having a surface rich in silicon and boron. The invention also relates to a method for manufacturing a positive electrode active material comprising lithium, oxygen, nickel, boron, and silicon, particularly having an enriched amount of silicon and boron in the surface layer; 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 can react slowly with non-aqueous or solid electrolytes, leading to 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 Ti or Zr) to a cathode active material (i.e., applying a thin surface layer of metal to the cathode active material, resulting in an increased or enriched amount of said metal in the surface layer) leads to improved electrochemical performance of the cathode active material compared to its counterparts without said surface layer.

[0006] Doo et al. (ACS Appl. Energy Mater. 2019, 2, 6246 6253) Considered the application of polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 Hydrophobic Ni-rich oxide materials were obtained by mixing with polydimethylsiloxane and then heating at 230°C, thereby improving the electrochemical stability of Ni-rich oxide materials.

[0007] However, there is still a need to provide positive electrode active materials with improved storage stability and / or improved electrochemical stability.

[0008] The purpose of this invention is to provide a positive electrode active material comprising silicon and boron to improve the storage stability and / or electrochemical performance of the positive electrode active material, particularly the efficiency of its initial discharge capacity and / or reversible capacity.

[0009] Another object of the present invention is to provide a method for manufacturing a positive electrode active material comprising silicon and boron.

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

[0011] Another object of the present invention is to provide the use of the battery. Summary of the Invention

[0012] In a first aspect, the object of the present invention is achieved by providing a positive electrode active material comprising lithium, oxygen, nickel, and at least one metal selected from the group consisting of manganese and cobalt, said positive electrode active material comprising:

[0013] a. Ni with a content of x' relative to the sum of Ni, Mn, and Co, where 40.0 ≤ x' ≤ 98.0 mol%. b. Mn content y' relative to the sum of Ni, Mn, and Co, where 0.0 ≤ y' ≤ 30.0 mol%. c. The amount of Co with a content of z' relative to the sum of Ni, Mn, and Co, where 0.0 ≤ z' ≤ 30.0 mol%. Where x', y', and z' are measured by ICP-OES, and The positive electrode active material has an enriched amount of silicon and boron in the surface layer.

[0014] In other words, and as those skilled in the art will understand, the positive electrode active material of the present invention has a surface layer comprising silicon and boron, particularly with Si and B in amounts higher than the average Si and B in the material.

[0015] The inventors have surprisingly discovered that the positive electrode active material of the present invention improves the electrochemical performance of batteries, particularly solid-state batteries (such as sulfide solid-state batteries), as demonstrated in the appended examples. Specifically, the positive electrode active material of the present invention increases the cycle efficiency of the battery and / or improves the initial discharge capacity of the battery.

[0016] Without being bound by any theory, the inventors have discovered that treating a cathode active material with polydimethylsiloxane and boric acid results in an enrichment of silicon and boron-containing compositions in the surface layer of the cathode active material. This composition differs from the composition present in the surface layer when the cathode active material is treated with silica and boric acid. The inventors have demonstrated this compositional difference through XPS analysis of the cathode active material of this invention: the binding energy level peak of the cathode active material treated with polydimethylsiloxane and boric acid is above 101.2 eV, while the cathode active material treated with silica and boric acid has a peak at a lower binding energy level of approximately 101.2 eV. The inventors attribute this change in binding energy level to the interaction between polydimethylsiloxane and boric acid in the surface layer of the cathode active material, resulting in the different binding energy level peaks. As is well known to those skilled in the art, the characteristic chemical state of atoms and their surrounding environment can cause a shift in binding energy.

[0017] Furthermore, the inventors believe that the enrichment of silicon and boron in the surface layer improves the storage stability of the positive electrode active material. In particular, by enriching the amount of silicon and boron in the surface layer of the positive electrode active material, the absorption of water and carbon (or carbon dioxide), preferably carbon, is expected to decrease.

[0018] Without being bound by any theory, the inventors believe that the silicon and boron enriched in the surface layer act as a hydrophobic surface layer, which inhibits the formation of residual lithium compounds such as Li2CO3 due to the reaction between lithium present in the positive electrode active material and water and carbon in the surrounding air, because the hydrophobic surface inhibits the contact between water and the positive electrode active material.

[0019] In another aspect, the present invention provides a method for manufacturing a positive electrode active material comprising lithium, oxygen, nickel, boron and silicon.

[0020] In another aspect, the present invention provides a battery comprising the aforementioned positive electrode active material.

[0021] In another aspect, the present invention provides the use of the battery. Attached Figure Description

[0022] Figure 1 XPS signals of CEX1.2, EX1.2 and EX2 between 98 eV and 106 eV.

[0023] Figure 2 SEM image of CEX1.1 containing polycrystalline particles.

[0024] Figure 3 SEM images of CEX2.1 containing single and secondary particles. Detailed Implementation

[0025] 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.

[0026] 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”.

[0027] As used herein and in the claims, the term "solid-state battery" refers to a battery cell or battery that comprises only solid-state components or basic solid-state components such as solid electrodes (e.g., anodes and cathodes) and a solid electrolyte.

[0028] 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 should be understood as a material capable of capturing and releasing Li ions when subjected to voltage variations over a predetermined time period.

[0029] 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, particularly conductive agents such as carbon black or binders such as PVDF.

[0030] 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).

[0031] In the context of this invention, the carbon content after exposure is measured by an exposure test, which involves uniformly spreading 40 grams of positive electrode active material in a 95 x 95 mm area. 2The process is performed on a tray placed in a 30°C room. Preferably, the atmosphere of the room is controlled to have a relative humidity level of 50%. Preferably, the positive electrode active material powder is removed after 3 days (72 hours) and carbon analysis is performed using a carbon analyzer.

[0032] In the context of this invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of positive electrode active material powder particles. As those skilled in the art will understand, in XPS measurements, the sample is measured from the top (…). Right now Signals are acquired in the first few nanometers (i.e., 1 nm to 10 nm) of the surface layer. In other words, all elements measured by XPS are contained within the surface layer. Preferably, monochromatic Al Kα radiation (hυ = 1486.6 eV) is used, with a spot size of 400 mm 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 limiting the invention, for surface analysis of positive electrode active material powder particles, XPS measurements are performed using a Thermo K-α+ spectrometer. For example, but not limited to the present invention, curve fitting is performed using Shirley-type background processing and Scofield sensitivity factor with CasaXPS version 2.3.19PR1.0, wherein preferably, the linear GL(30) is a Gaussian / Lorentz product formula with 70% Gaussian line and 30% Lorentz line.

[0033] In the context of this invention, a positive electrode active material having an enriched amount of silicon and / or boron in the surface layer of the positive electrode active material means that the positive electrode active material has a surface layer containing silicon and / or boron. The presence of these enriched amounts of silicon and boron in the surface layer containing silicon and boron is evidenced by SiB / SiA and / or BB / BA ratios greater than 1, indicating that the B and / or Si are primarily present on the surface of the positive electrode active material.

[0034] Positive electrode active material In a first aspect, the present invention relates to a positive electrode active material for a battery, said positive electrode active material comprising lithium, oxygen, nickel, and at least one metal selected from the group consisting of manganese and cobalt. The positive electrode active material further comprises B in a certain amount. B Boron, of which B B It is expressed as the mole fraction of B relative to the total amount of Ni, Mn, Co, Si, and B, as measured by XPS analysis. Among them B B >0.30.

[0035] A highly preferred embodiment is the positive electrode active material of the present invention for use in solid-state batteries.

[0036] A particularly preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material exhibits a binding energy level peak between 101.4 eV and 106.0 eV as measured by XPS analysis. More preferably, the positive electrode active material exhibits a binding energy level peak between 101.4 eV and 105.0 eV, preferably between 101.5 eV and 104.5 eV, and more preferably between 101.6 eV and 104.0 eV as measured by XPS analysis.

[0037] A particular highly preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material further comprises silicon.

[0038] A particular highly preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material comprises silicon; and The positive electrode active material exhibits a binding energy level peak between 101.3 eV and 106.0 eV as measured by XPS analysis, preferably between 101.4 eV and 106.0 eV as measured by XPS analysis, more preferably between 101.5 eV and 105.0 eV, and most preferably between 101.6 eV and 104.0 eV.

[0039] A particular preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material comprises silicon, the silicon exhibiting a peak of a binding energy level between 101.3 eV and 106.0 eV as measured by XPS analysis, preferably between 101.4 eV and 106.0 eV as measured by XPS analysis, more preferably between 101.5 eV and 105.0 eV, and most preferably between 101.6 eV and 104.0 eV.

[0040] A particular highly preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material comprises a Si content of B Silicon, in which Si B Expressed as the mole fraction of Si relative to the total amounts of Ni, Mn, Co, Si, and B, as measured by XPS analysis, and Where Si B >0.01.

[0041] A particular highly preferred embodiment is the positive electrode active material of the present invention, wherein the positive electrode active material comprises a Si content ofB Silicon, in which Si B Expressed as the mole fraction of Si relative to the total amount of Ni, Mn, Co, Si, and B, as measured by XPS analysis; Where Si B >0.01; and The positive electrode active material exhibits a binding energy level peak between 101.3 eV and 106.0 eV as measured by XPS analysis, preferably between 101.4 eV and 106.0 eV as measured by XPS analysis, more preferably between 101.5 eV and 105.0 eV, and most preferably between 101.6 eV and 104.0 eV.

[0042] A preferred embodiment is the positive electrode active material of the present invention, which has a layered structure, preferably an α-NaFeO2 type layered structure, and more preferably an α-NaFeO2 type layered structure with R-3m space group.

[0043] A preferred embodiment is the positive electrode active material of the present invention comprising Li, Ni, Mn, Co and oxygen, wherein the Ni content is x' relative to the sum of Ni, Mn and Co, wherein 50.0 ≤ x' ≤ 98.0 mol%. A more preferred embodiment is the positive electrode active material of the present invention, wherein the Ni content is x' ≥ 55.0 mol% relative to the sum of Ni, Mn and Co, preferably x' ≥ 58.0 mol%, more preferably x' ≥ 60.0 mol%. In a preferred embodiment, the Ni content is x' ≤ 90.0 mol% relative to the sum of Ni, Mn and Co, preferably x' ≤ 88 mol%, more preferably x' ≤ 85.0 mol%. A more preferred embodiment is the positive electrode active material of the present invention, wherein the Ni content x' relative to the sum of Ni, Mn and Co is between 55.0 mol% ≤ x' ≤ 90.0 mol%, preferably 58.0 mol% ≤ x' ≤ 88.0 mol%, more preferably 60.0 mol% ≤ x' ≤ 85.0 mol%.

[0044] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Ni is x'≥55.0 mol%, preferably x'≥58.0 mol%, more preferably x'≥60.0 mol% relative to the sum of Ni, Mn and Co. In a specific preferred embodiment, the content of Ni is x'≤75.0 mol%, preferably x'≤72 mol%, more preferably x'≤70.0 mol% relative to the sum of Ni, Mn and Co. A more specific preferred embodiment is the positive electrode active material of the present invention, wherein the content of Ni, x', is between 55.0 mol%≤x'≤75.0 mol%, preferably 58.0 mol%≤x'≤72.0 mol%, more preferably 60.0 mol%≤x'≤70.0 mol% relative to the sum of Ni, Mn and Co.

[0045] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Ni is x'≥75.0 mol%, preferably x'≥78.0 mol%, more preferably x'≥80.0 mol% relative to the sum of Ni, Mn and Co. In a specific preferred embodiment, the content of Ni is x'≤92.0 mol%, preferably x'≤90 mol%, and more preferably x'≤88.0 mol% relative to the sum of Ni, Mn and Co. A more specific preferred embodiment is the positive electrode active material of the present invention, wherein the content of Ni, x', is between 75.0 mol%≤x'≤92.0 mol%, preferably 78.0 mol%≤x'≤90.0 mol%, more preferably 80.0 mol%≤x'≤88.0 mol% relative to the sum of Ni, Mn and Co.

[0046] A preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Mn is y' relative to the sum of Ni, Mn and Co, where 0.0≤y'≤30.0 mol%. A more preferred embodiment is the positive electrode active material of the present invention, wherein the content of Mn is y'>0.0 mol%, preferably y'≥1.0 mol%, more preferably y'≥2.0 mol% relative to the sum of Ni, Mn and Co. In a more preferred embodiment, the content is y'≤20.0 mol%, preferably y'≤15.0 mol%, and more preferably y'≤10.0 mol% relative to the sum of Ni, Mn and Co. In a more preferred embodiment, the content of Mn is 0.0 mol%<y'≤20.0 mol%, preferably 1.0 mol%≤y'≤15.0 mol%, more preferably 2.0 mol%≤y'≤10.0 mol% relative to the sum of Ni, Mn and Co.

[0047] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Mn is y'>0.0 mol%, preferably y'≥5.0 mol%, more preferably y'≥10.0 mol% relative to the sum of Ni, Mn and Co. In a specific preferred embodiment, the content is y'≤30.0 mol%, preferably y'≤25.0 mol%, and more preferably y'≤20.0 mol% relative to the sum of Ni, Mn and Co. In a specific preferred embodiment, the content of Mn is 0.0 mol%<y'≤30.0 mol%, preferably 5.0 mol%≤y'≤25.0 mol%, more preferably 10.0 mol%≤y'≤20.0 mol% relative to the sum of Ni, Mn and Co.

[0048] A preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Co is z' relative to the sum of Ni, Mn and Co, where 0.0≤z'≤30.0 mol%. In a more preferred embodiment, the content of Co is z'>0.0 mol%, preferably z'≥1.0 mol%, more preferably z'≥2.0 mol% relative to the sum of Ni, Mn and Co. In a preferred embodiment, the content is z'≤20.0 mol%, preferably z'≤15.0 mol%, and more preferably z'≤10.0 mol% relative to the sum of Ni, Mn and Co. In a preferred embodiment, the content of Co is 0.0 mol%<z'≤20.0 mol%, preferably 1.0 mol%≤z'≤15.0 mol%, more preferably 2.0 mol%≤z'≤10.0 mol% relative to the sum of Ni, Mn and Co.

[0049] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein the content of Co is z'>0.0 mol%, preferably z'≥5.0 mol%, more preferably z'≥10.0 mol% relative to the sum of Ni, Mn and Co. In a preferred embodiment, the content is z'≤30.0 mol%, preferably z'≤25.0 mol%, and more preferably z'≤20.0 mol% relative to the sum of Ni, Mn and Co. In a preferred embodiment, the content of Co is 0.0 mol%<z'≤30.0 mol%, preferably 5.0 mol%≤z'≤25.0 mol%, more preferably 10.0 mol%≤z'≤20.0 mol% relative to the sum of Ni, Mn and Co.

[0050] A more preferred embodiment is the positive electrode active material of the present invention containing Li, Ni, Mn, Co and oxygen, wherein: a. Ni having a content of x' relative to the sum of Ni, Mn, and Co, where 40.0 ≤ x' ≤ 98.0 mol%, b. Mn having a content of y' relative to the sum of Ni, Mn, and Co, where 0.0 ≤ y' ≤ 30.0 mol%, c. Co having a content of z' relative to the sum of Ni, Mn, and Co, where 0.0 ≤ z' ≤ 30.0 mol%, where x', y', and z' are measured by ICP - OES.

[0051] A more highly preferred embodiment is the positive electrode active material of the present invention comprising Li, Ni, Mn, Co, and oxygen, wherein: a. The content x' of Ni is between 75.0 mol% ≤ x' ≤ 92.0 mol% relative to the sum of Ni, Mn, and Co, preferably 78.0 mol% ≤ x' ≤ 90.0 mol%, more preferably 80.0 mol% ≤ x' ≤ 88.0 mol%, b. The content of Mn is 0.0 mol% < y' ≤ 20.0 mol% relative to the sum of Ni, Mn, and Co, preferably 1.0 mol% ≤ y' ≤ 15.0 mol%, more preferably 2.0 mol% ≤ y' ≤ 10.0 mol%, c. The content of Co is 0.0 mol% < z' ≤ 20.0 mol% relative to the sum of Ni, Mn, and Co, preferably 1.0 mol% ≤ z' ≤ 15.0 mol%, more preferably 2.0 mol% ≤ z' ≤ 10.0 mol%, and where x', y', and z' are measured by ICP - OES.

[0052] As understood by those skilled in the art, the amounts of Li, Ni, Mn, and Co in the positive electrode active material are measured by inductively coupled plasma optical emission spectrometry (ICP - OES). In other words, x', y', and z' are measured by ICP - OES. For example, but not limited to the present invention, an Agilent ICP 720 - ES is used in the ICP - OES analysis.

[0053] One preferred embodiment is the positive electrode active material of the present invention, which has a Li / (Ni + Mn + Co) ratio (mol / mol) > 0.90, preferably > 0.92, more preferably > 0.95. One preferred embodiment is the positive electrode active material of the present invention, which has a Li / (Ni + Mn + Co) ratio (mol / mol) < 1.10, preferably < 1.08, more preferably < 1.05. One preferred embodiment is the positive electrode active material of the present invention, which has a Li / (Ni + Mn + Co) ratio (mol / mol) within the range of 0.90 - 1.10, preferably within the range of 0.92 - 1.08, more preferably within the range of 0.95 - 1.05.

[0054] A highly preferred embodiment is the positive electrode active material of the present invention containing Li, M' and oxygen, where M' includes: a. Ni with a content of x relative to M', where 28.0 ≤ x ≤ 98.0 mol%, preferably where relative to M', 50.0 ≤ x ≤ 98.0 mol%, b. Mn with a content of y relative to M', where 0.0 ≤ y ≤ 30.0 mol%, c. Co with a content of z relative to M', where 0.0 ≤ z ≤ 30.0 mol%, d. Si with a content of a relative to M', where 0.0 < a ≤ 5.0 mol%, e. B with a content of b relative to M', where 0.0 < b ≤ 5.0 mol%, f. D with a content of d relative to M', where 0.0 ≤ d ≤ 2.0 mol%, where D is an element different from Li, Ni, Mn, Co, Si, B and oxygen; where x, y, z, a, b and d are measured by ICP - OES, and where x + y + z + a + b + d is 100.0 mol%.

[0055] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, M' and oxygen, where M' includes: a. Ni with a content of x relative to M', where 58.0 ≤ x ≤ 98.0 mol%, b. Mn with a content of y relative to M', where 0.0 ≤ y ≤ 15.0 mol%, c. Co with a content of z relative to M', where 0.0 ≤ z ≤ 15.0 mol%, d. Si with a content of a relative to M', where 0.0 < a ≤ 5.0 mol%, e. B having a content of b relative to M', where 0.0 < b ≤ 5.0 mol%, f. D having a content of d relative to M', where 0.0 ≤ d ≤ 2.0 mol%, where D is an element different from Li, Ni, Mn, Co, Si, B, and oxygen; where x, y, z, a, b, and d are measured by ICP - OES, and where x + y + z + a + b + d is 100.0 mol%.

[0056] As understood by those skilled in the art, the amounts of Li and M' (preferably Li, Ni, Mn, Co, D, and Si) in the positive electrode active material are measured by inductively coupled plasma optical emission spectrometry (ICP - OES). In other words, x, y, z, a, b, and d are measured by ICP - OES. For example, but not limited to the present invention, Agilent ICP 720 - ES is used in ICP - OES analysis.

[0057] A more preferred embodiment is the positive electrode active material of the present invention comprising Li, M', and oxygen, where M' includes Ni and has a content of x ≥ 55.0 mol% relative to M', preferably x ≥ 58.0 mol%, more preferably x ≥ 60.0 mol%. In a preferred embodiment, the content of Ni is x ≤ 90.0 mol% relative to M', preferably x ≤ 88 mol%, more preferably x ≤ 85.0 mol%. A more preferred embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is between 55.0 mol% ≤ x ≤ 90.0 mol%, preferably between 58.0 mol% ≤ x ≤ 88.0 mol%, more preferably between 60.0 mol% ≤ x ≤ 85.0 mol%.

[0058] A specific preferred embodiment is the positive electrode active material of the present invention comprising Li, M', and oxygen, where M' includes Ni and has a content of x ≥ 55.0 mol% relative to M', preferably x ≥ 58.0 mol%, more preferably x ≥ 60.0 mol%. In a specific preferred embodiment, the content of Ni is x ≤ 75.0 mol% relative to M', preferably x ≤ 72 mol%, more preferably x ≤ 70.0 mol%. A specific more preferred embodiment is the positive electrode active material of the present invention, where the content of Ni, x, is between 55.0 mol% ≤ x ≤ 75.0 mol%, preferably between 58.0 mol% ≤ x ≤ 72.0 mol%, more preferably between 60.0 mol% ≤ x ≤ 70.0 mol%.

[0059] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, M', and oxygen, where M' includes Ni, and its content is x ≥ 75.0 mol%, preferably x ≥ 78.0 mol%, more preferably x ≥ 80.0 mol% relative to M'. In a specific preferred embodiment, relative to M', the content of Ni is x ≤ 92.0 mol%, preferably x ≤ 90 mol%, and more preferably x ≤ 88.0 mol%. A specific more preferred embodiment is the positive electrode active material of the present invention, where relative to M', the content x of Ni is between 75.0 mol% ≤ x ≤ 92.0 mol%, preferably between 78.0 mol% ≤ x ≤ 90.0 mol%, more preferably between 80.0 mol% ≤ x ≤ 88.0 mol%.

[0060] A more preferred embodiment is the positive electrode active material of the present invention containing Li, M', and oxygen, where M' includes Mn, and its content is y > 0.0 mol%, preferably y ≥ 1.0 mol%, more preferably y ≥ 2.0 mol% relative to M'. In a more preferred embodiment, relative to M', the content is y ≤ 20.0 mol%, preferably y ≤ 15.0 mol%, more preferably y ≤ 10.0 mol%. In a more preferred embodiment, relative to M', the content of Mn is 0.0 mol% < y ≤ 20.0 mol%, preferably 1.0 mol% ≤ y ≤ 15.0 mol%, more preferably 2.0 mol% ≤ y ≤ 10.0 mol%.

[0061] A specific preferred embodiment is the positive electrode active material of the present invention containing Li, M', and oxygen, where M' includes Mn, and its content is y > 0.0 mol%, preferably y ≥ 5.0 mol%, more preferably y ≥ 10.0 mol% relative to M'. In a specific preferred embodiment, relative to M', the content is y ≤ 30.0 mol%, preferably y ≤ 25.0 mol%, more preferably y ≤ 20.0 mol%. In a specific preferred embodiment, relative to M', the content of Mn is 0.0 mol% < y ≤ 30.0 mol%, preferably 5.0 mol% ≤ y ≤ 25.0 mol%, more preferably 10.0 mol% ≤ y ≤ 20.0 mol%.

[0062] A more preferred embodiment is the positive electrode active material of the present invention comprising Li, M' and oxygen, wherein M' comprises Co, and its content is z > 0.0 mol%, preferably z ≥ 1.0 mol%, more preferably z ≥ 2.0 mol% relative to M'. In a preferred embodiment, the content is z ≤ 20.0 mol%, preferably z ≤ 15.0 mol%, and more preferably z ≤ 10.0 mol% relative to M'. In a preferred embodiment, the content of Co is 0.0 mol% < z ≤ 20.0 mol%, preferably 1.0 mol% ≤ z ≤ 15.0 mol%, more preferably 2.0 mol% ≤ z ≤ 10.0 mol% relative to M'.

[0063] A specific preferred embodiment is the positive electrode active material of the present invention comprising Li, M' and oxygen, wherein M' comprises Co, and its content is z > 0.0 mol%, preferably z ≥ 5.0 mol%, more preferably z ≥ 10.0 mol% relative to M'. In a preferred embodiment, the content is z ≤ 30.0 mol%, preferably z ≤ 25.0 mol%, more preferably z ≤ 20.0 mol% relative to M'. In a preferred embodiment, the content of Co is 0.0 mol% < z ≤ 30.0 mol%, preferably 5.0 mol% ≤ z ≤ 25.0 mol%, more preferably 10.0 mol% ≤ z ≤ 20.0 mol% relative to M'.

[0064] A preferred embodiment is the positive electrode active material according to the present invention comprising Li, M' and oxygen, wherein M' comprises Si, and its content is a > 0.01 mol%, preferably a ≥ 0.03 mol%, more preferably a ≥ 0.06 mol% relative to M'. In a preferred embodiment, the content a ≤ 2.0 mol%, preferably a ≤ 1.0 mol%, more preferably a ≤ 0.1 mol% relative to M'. In a preferred embodiment, the content a is 0.01 mol% < a ≤ 2.0 mol%, preferably 0.03 mol% ≤ a ≤ 1.0 mol%, more preferably 0.06 mol% ≤ a ≤ 0.1 mol% relative to M'.

[0065] One preferred embodiment is the positive electrode active material according to the present invention that contains Li, M', and oxygen, where M' includes B, and relative to M', its content b > 0.01 mol%, preferably b ≥ 0.1 mol%, more preferably b ≥ 0.4 mol%. In one preferred embodiment, relative to M', the content b ≤ 4.0 mol%, preferably b ≤ 3.0 mol%, more preferably b ≤ 2.0 mol%. In one preferred embodiment, relative to M', the content b is 0.01 mol% < b ≤ 4.0 mol%, preferably 0.1 mol% ≤ b ≤ 3.0 mol%, more preferably 0.4 mol% ≤ b ≤ 2.0 mol%. In a specific preferred embodiment, relative to M', the content b is 0.5 mol% < b ≤ 4.0 mol%, preferably 0.7 mol% ≤ b ≤ 3.0 mol%, more preferably 0.8 mol% ≤ b ≤ 2.0 mol%.

[0066] As known to those skilled in the art, the positive electrode active material of the present invention may contain impurities on the surface or be doped with or contain metals, resulting in the entire positive electrode active material containing one or more elements other than Li, Ni, Mn, Co, Si, B, and O, which is reflected in the parameter "D" used herein. One preferred embodiment is the positive electrode active material according to the present invention that contains D, where D is at least one element selected from the group consisting of: Al, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Sr, Ti, V, W, Y, Zn, and Zr; preferably Al, Ti, Cr, Nb, S, Y, and W; more preferably Al, Ti, Nb, and W.

[0067] One preferred embodiment is the positive electrode active material according to the present invention that contains Li, M', and oxygen, where M' includes D, and relative to M', its content d > 0.0 mol%, preferably d ≥ 0.25 mol%, more preferably d ≥ 0.5 mol%. In one preferred embodiment, relative to M', the content d ≤ 1.75 mol%, preferably d ≤ 1.5 mol%, more preferably d ≤ 1.25 mol%. In one preferred embodiment, relative to M', the content d is 0.0 mol% < d ≤ 1.75 mol%, preferably 0.25 mol% ≤ d ≤ 1.5 mol%, more preferably 0.5 mol% ≤ d ≤ 1.25 mol%.

[0068] 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 mol%.

[0069] A more highly preferred embodiment is the positive electrode active material of the present invention that contains Li, M', and oxygen, where M' includes: a. Ni with a content of x relative to M', where 75.0 mol% ≤ x ≤ 92.0 mol%, preferably 78.0 mol% ≤ x ≤ 90.0 mol%, more preferably 80.0 mol% ≤ x ≤ 88.0 mol%, b. Mn with a content of y relative to M', where 0.0 mol% < y ≤ 20.0 mol%, preferably 1.0 mol% ≤ y ≤ 15.0 mol%, more preferably 2.0 mol% ≤ y ≤ 10.0 mol%, c. Co with a content of z relative to M', where 0.0 mol% < z ≤ 20.0 mol%, preferably 1.0 mol% ≤ z ≤ 15.0 mol%, more preferably 2.0 mol% ≤ z ≤ 10.0 mol%, d. Si with a content of a relative to M', where 0.01 mol% < a ≤ 2.0 mol%, preferably 0.03 mol% ≤ a ≤ 1.0 mol%, more preferably 0.06 mol% ≤ a ≤ 0.1 mol%, e. B with a content of b relative to M', where 0.01 mol% < b ≤ 4.0 mol%, preferably 0.1 mol% ≤ b ≤ 3.0 mol%, more preferably 0.4 mol% ≤ b ≤ 2.0 mol%, f. D with a content of d relative to M', where 0.0 mol% < d ≤ 1.75 mol%, preferably 0.25 mol% ≤ d ≤ 1.5 mol%, more preferably 0.5 mol% ≤ d ≤ 1.25 mol%, where D is an element different from Li, Ni, Mn, Co, Si, B, and oxygen; where x, y, z, a, b, and d are measured by ICP - OES, and where x + y + z + a + b + d is 100.0 mol%.

[0070] A preferred embodiment is the positive electrode active material of the present invention, which has a Li / M' ratio (mol / mol), preferably a Li / (Ni + Mn + Co) ratio (mol / mol), greater than 0.90, preferably greater than 0.92, more preferably greater than 0.95. A preferred embodiment is the positive electrode active material of the present invention, which has a Li / M' ratio (mol / mol), preferably a Li / (Ni + Mn + Co) ratio (mol / mol), less than 1.10, preferably less than 1.08, more preferably less than 1.05. A preferred embodiment is the positive electrode active material of the present invention, which has a Li / M' ratio (mol / mol), preferably a Li / (Ni + Mn + Co) ratio (mol / mol), within the range of 0.90 - 1.10, preferably within the range of 0.92 - 1.08, more preferably within the range of 0.95 - 1.05.

[0071] A highly preferred embodiment is the positive electrode active material of the present invention according to formula (I): Li w'' Ni x'' Mn y'' Co z'' Si a'' B b'' D d'' O2(I) a. wherein 0.90 ≤ w'' ≤ 1.10, preferably 0.92 ≤ w'' ≤ 1.08, more preferably 0.95 ≤ w'' ≤ 1.05; b. wherein 0.75 ≤ x'' ≤ 0.92, preferably 0.78 ≤ x'' ≤ 0.90, more preferably 0.80 ≤ x'' ≤ 0.88; c. wherein 0.0 < y'' ≤ 0.20, preferably 0.01 ≤ y'' ≤ 0.15, more preferably 0.02 ≤ y'' ≤ 0.10; d. wherein 0.0 < z'' ≤ 0.20, preferably 0.01 ≤ z'' ≤ 0.15, more preferably 0.02 ≤ z'' ≤ 0.10; e. wherein 0.0001 ≤ a'' ≤ 0.02, preferably 0.0003 ≤ a'' ≤ 0.01, more preferably 0.0006 ≤ a'' ≤ 0.001; f. wherein 0.0001 ≤ b'' ≤ 0.04, preferably 0.001 ≤ b'' ≤ 0.03, more preferably 0.004 ≤ b'' ≤ 0.02; g. wherein 0.0001 ≤ d'' ≤ 0.0175, preferably 0.0025 ≤ d'' ≤ 0.015, more preferably 0.005 ≤ d'' ≤ 0.0125; and h. wherein x'' + y'' + z'' + a'' + b'' + d'' = 1.0.

[0072] As understood by those skilled in the art, the amounts of w'', x'', y'', z'', a'', b'' and d'' in the positive electrode active material are measured by inductively coupled plasma optical emission spectrometry (ICP-OES). For example, but not limited to the present invention, Agilent ICP 720-ES is used in the ICP-OES analysis.

[0073] A preferred embodiment is the positive electrode active material of the present invention, having a carbon content greater than 100 ppm by weight of the total positive electrode active material, preferably greater than 150 ppm by weight of the total positive electrode active material, and more preferably greater than 200 ppm by weight of the total positive electrode active material. A preferred embodiment is the positive electrode active material of the present invention, having a carbon content less than 1000 ppm by weight of the total positive electrode active material, preferably less than 750 ppm by weight of the total positive electrode active material, and more preferably less than 550 ppm by weight of the total positive electrode active material. A preferred embodiment is the positive electrode active material of the present invention, having a carbon content in the range of 100 ppm to 1000 ppm by weight of the total positive electrode active material, preferably in the range of 150 ppm to 750 ppm by weight of the total positive electrode active material, and more preferably in the range of 200 ppm to 550 ppm by weight of the total positive electrode active material.

[0074] As those skilled in the art will understand, the carbon content of the positive electrode active material of the present invention is measured using a carbon analyzer. For example, but not limited to the present invention, a Horiba Emia-Expert carbon / sulfur analyzer can be used to measure the carbon content. Furthermore, the carbon content of the positive electrode active material of the present invention is measured prior to an exposure test as defined in the present invention.

[0075] In a preferred embodiment of the invention, the positive electrode active material of the present invention has a carbon absorption of less than 1500 ppm carbon by weight of the total positive electrode active material, preferably less than 1300 ppm carbon by weight of the total positive electrode active material, and more preferably less than 1200 ppm carbon by weight of the total positive electrode active material. As will be understood by those skilled in the art, the carbon absorption is measured after an exposure test as defined in the present invention. In a particular preferred embodiment of the invention, it has a carbon absorption of less than 1000 ppm carbon by weight of the total positive electrode active material, preferably less than 500 ppm carbon by weight of the total positive electrode active material, and more preferably less than 445 ppm carbon by weight of the total positive electrode active material.

[0076] In a preferred embodiment of the invention, the positive electrode active material of the invention has a carbon absorption of less than 340% carbon by weight of the total positive electrode active material, preferably less than 245% carbon by weight of the total positive electrode active material, and more preferably less than 200% carbon by weight of the total positive electrode active material. As those skilled in the art will understand, the carbon absorption is measured after an exposure test as defined in this invention.

[0077] Surface layer This invention provides a positive electrode active material according to the invention, wherein the positive electrode active material contains a content of B. B Boron, of which B BExpressed as the mole fraction of B relative to the total amounts of Ni, Mn, Co, and Si, as measured by XPS analysis, where B B >0.30.

[0078] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein B B >0.35, preferably B B >0.4, more preferably B B >0.68. In a preferred embodiment, the positive electrode active material is according to the invention, wherein B B <5.0, preferably B B <2.0, more preferably B B <1.0. In a preferred embodiment, the positive electrode active material is according to the invention, wherein B B Within the range of 0.35 to 5.0, B is preferred. B More preferably, B is preferred within the range of 0.4 to 2.0. B It is in the range of 0.68 to 1.0.

[0079] In one embodiment, the positive electrode active material is according to the present invention, wherein the positive electrode active material comprises a content of B. C Boron, of which B C Expressed as the mole fraction of B relative to the total amounts of Ni, Mn, and Co, as measured by XPS analysis, where B C >1.0.

[0080] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein B C >3.0, preferably B C >10.0, more preferably B C >50.0. In a preferred embodiment, B C <1000.0, preferably B C <500.0, more preferably B C <100.0. In a preferred embodiment, B C Within the range of 3.0 to 1000.0, B is preferred. C More preferably, B, within the range of 10.0 to 500.0. C In the range of 50.0 to 100.0.

[0081] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein the positive electrode active material has a B content defined as B / (x+y+z+a+b). A , a. Among them, the positive electrode active material has a B content of B. B BB Expressed as the mole fraction of B relative to the total amounts of Ni, Mn, Co, Si, and B, as measured by XPS analysis, and b. Among them, ratio B B / B A >5.0.

[0082] In a more preferred embodiment, the positive electrode active material is according to the present invention, wherein the ratio B B / B A >35, preferably ratio B B / B A >45, more preferably ratio B B / B A >72. In a more preferred embodiment, the positive electrode active material is according to the invention, wherein the ratio B B / B A <1000, preferably ratio B B / B A <500, more preferably ratio B B / B A <100. In a more preferred embodiment, the positive electrode active material is according to the invention, wherein the ratio B B / B A Within the range of 35 to 1000, the preferred ratio B B / B A Within the range of 45 to 500, a more preferred ratio B B / B A The range is between 72 and 100.

[0083] In the context of this invention, B B Or B C The mole fraction of B relative to the total amount of Ni, Mn, Co, Si, and B, or relative to the total amount of Ni, Mn, and Co, is measured in a region of the positive electrode active material particles according to the invention. This region is defined between a first point on the outer edge of the particles and a second point at a certain distance from the first point. The distance between the first point and the second point is equal to the penetration depth of the XPS, which is between 1.0 nm and 10.0 nm. 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.

[0084] Within the framework of this invention, the outer edge of a particle is the boundary or external constraint that distinguishes the particle from its external environment. Therefore, XPS analysis provides the atomic content of elements in the uppermost layer of the particle, with a penetration depth of approximately 10.0 nm from the outer boundary of the particle. The outer boundary of the particle is also referred to as the "surface." For example, but not limited to this invention, XPS analysis is performed using a Thermo K-α+ spectrometer (Thermo Scientific).

[0085] Within the framework of this invention, atom% represents the percentage of atoms. In the expression of concentration, atom% 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 atom% is equivalent to mole% or "molar percentage".

[0086] As understood by the technicians, the defined ratio B B / B A This refers to the positive electrode active material of the present invention having an enriched amount of B in its surface layer. The surface layer of the positive electrode active material is the uppermost 1 nm to 10 nm of the positive electrode active material. In other words, the positive electrode active material of the present invention contains a surface layer of B. For example, but not limiting the present invention, the compound of B present in the surface layer of the positive electrode active material is LiBO2, LiB3O5, LiB5O8, or a combination thereof.

[0087] A highly preferred embodiment of the present invention is a positive electrode active material according to the present invention, wherein the positive electrode active material comprises a Si content B Silicon, in which Si B Expressed as the mole fraction of Si relative to the total amounts of Ni, Mn, Co, and Si and B, as measured by XPS analysis, where Si B >0.01.

[0088] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein Si B >0.03, preferably Si B >0.05, more preferably Si B >0.08. In a preferred embodiment, the positive electrode active material is according to the invention, wherein Si B <1.0, preferably Si B <0.3, more preferably Si B <0.2. In a preferred embodiment, the positive electrode active material is according to the present invention, wherein Si B In the range of 0.03 to 1.0, Si is preferred. B More preferably, Si is found in the range of 0.05 to 0.3. BIt is in the range of 0.08 to 0.2.

[0089] In one embodiment, the positive electrode active material is according to the present invention, wherein the positive electrode active material further comprises a Si content. C Silicon, in which Si C Expressed as the mole fraction of Si relative to the total amounts of Ni, Mn, and Co, as measured by XPS analysis, where Si C >0.3.

[0090] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein Si C >0.5, preferably Si C >1.0, more preferably Si C >5.0. In a preferred embodiment, Si C <500.0, preferably Si C <100.0, more preferably Si C <50.0. In a preferred embodiment, Si C In the range of 0.5 to 500.0, Si is preferred. C More preferably, Si is found in the range of 1.0 to 100.0. C Within the range of 5.0 to 50.0.

[0091] In a preferred embodiment, the positive electrode active material is according to the present invention, wherein the positive electrode active material has a Si content defined as a / (x+y+z+a+b). A , a. Among them, the positive electrode active material has a Si content of Si B Si B Expressed as the mole fraction of Si relative to the total amounts of Ni, Mn, Co, Si, and B, as measured by XPS analysis, and b. Where the ratio Si B / Si A >30.0.

[0092] In a more preferred embodiment, the positive electrode active material is according to the present invention, wherein the ratio of Si is... B / Si A >35, preferred ratio B / Si A >50, more preferably, the ratio of Si B / Si A >100. In a more preferred embodiment, the positive electrode active material is according to the invention, wherein the ratio of Si... B / Si A <1000, preferably ratio Si B / Si A <400, more preferably, the ratio of Si B / Si A <250. In a more preferred embodiment, the positive electrode active material is according to the invention, wherein the ratio of Si... B / Si A In the range of 35 to 1000, the preferred ratio Si is... B / Si A More preferably, the ratio of Si is within the range of 50 to 400. B / Si A In the range of 100 to 250.

[0093] In the context of this invention, Si B or Si C The mole fraction of Si relative to the total amount of Ni, Mn, Co, Si, and B, or relative to the total amount of Ni, Mn, and Co, is measured in a region of the positive electrode active material particles according to the invention. This region is defined between a first point on the outer edge of the particles and a second point at a certain distance from the first point. The distance between the first point and the second point is equal to the penetration depth of the XPS, wherein the penetration depth D' is between 1.0 nm and 10.0 nm. 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.

[0094] As understood by the technician, the defined ratio Si B / Si A This refers to the positive electrode active material of the present invention having an enriched amount of Si in its surface layer. The surface layer of the positive electrode active material is the uppermost 1 nm to 10 nm of the positive electrode active material. In other words, the positive electrode active material of the present invention includes a surface layer of Si. For example, but not limited to the present invention, the compound of Si present in the surface layer of the positive electrode active material is Li₂SiO₃.

[0095] In the context of this invention, in addition to enriched amounts of boron and silicon, the positive electrode active material may also contain D, wherein D is at least one element selected from the group consisting of: Al, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Sr, Ti, V, W, Y, Zn and Zr; preferably Al, Ti, Cr, Nb, S, Y and W; more preferably Al, Ti, Nb and W.

[0096] A particular preferred embodiment relates to the positive electrode active material of the present invention, which has: a. B in the range of 0.35 to 5.0 B The content of B is preferably in the range of 0.4 to 2.0.B More preferably, B is in the range of 0.68 to 1.0. B ;as well as b. Si in the range of 0.03 to 1.0, preferably in the range of 0.05 to 0.3, and more preferably in the range of 0.08 to 0.2. B content.

[0097] A particular preferred embodiment relates to the positive electrode active material of the present invention, which has: a. Ratio B in the range of 35 to 1000 B / B A Preferably, the ratio B is in the range of 45 to 500. B / B A More preferably, the ratio B is in the range of 72 to 100. B / B A ;as well as b. Si in the range of 0.03 to 1.0, preferably in the range of 0.05 to 0.3, and more preferably in the range of 0.08 to 0.2. B content.

[0098] A particular preferred embodiment relates to the positive electrode active material of the present invention, which has: a. Ratio B in the range of 35 to 1000 B / B A Preferably, the ratio B is in the range of 45 to 500. B / B A More preferably, the ratio B is in the range of 72 to 100. B / B A ;as well as b. The ratio Si in the range of 35 to 1000 B / Si A Preferably, the ratio Si is in the range of 50 to 400. B / Si A More preferably, the ratio of Si is in the range of 100 to 250. B / Si A .

[0099] form In a particular preferred embodiment, the present invention provides a positive electrode active material according to the invention, wherein the positive electrode active material is a powder comprising single particles and / or secondary particles, wherein, as observed in a SEM image, each of the single particles consists of only one primary particle, and each of the secondary particles consists of at least two and at most twenty primary particles. Preferably, at least 30% of the particles constituting the powder observed in the SEM image, more preferably at least 50% of the particles, 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 x at least 60 μm (i.e., at least 2700 μm²), preferably at least 100 μm x 100 μm (i.e., at least 10000 μm²). The particles in the image should be uniformly distributed to avoid overlap between particles. This can be achieved by pouring a small amount of powder sample onto an adhesive attached to a SEM sample holder and blowing air to remove excess powder.

[0100] In the context of this invention, primary particles are distinguished 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 arranged in different orientations and meet as crystal discontinuities.

[0101] Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the positive electrode active material is a powder comprising single particles and / or secondary particles, wherein the particles constituting the powder have a median D50 value of less than 15 μm, preferably less than 10 μm, more preferably less than 5 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the particles constituting the powder have a median D50 value of greater than 1 μm, preferably greater than 2 μm, more preferably greater than 3 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the particles constituting the powder have a median D50 value between 1 and 15 μm, preferably between 2 and 10 μm, more preferably between 3 and 5 μm.

[0102] 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 by a Malvern Mastersizer 3000 with Hydro MV measurement. For example, but not limited to the present invention, the particle value D50 can be measured using a Malvern Mastersizer 3000.

[0103] In some preferred embodiments, the positive electrode active material of the present invention comprises polycrystalline particles.

[0104] As understood by those skilled in the art, polycrystalline particles are agglomerated from more than 20 primary particles, preferably 50 or more, and more preferably 100 or more. Therefore, in a particular preferred embodiment, the positive electrode active material is a powder comprising polycrystalline particles, wherein, as observed in the SEM image, each of the polycrystalline particles consists of more than 20 primary particles, preferably 50 or more, and more preferably 100 or more. Preferably, at least 30% of the particles constituting the powder, more preferably at least 50%, are polycrystalline particles as observed in the SEM image. The number of primary particles constituting the polycrystalline particles is determined in a field of view of at least 45 μm x at least 60 μm (i.e., at least 2700 μm²), preferably at least 100 μm x 100 μm (i.e., at least 10,000 μm²). The particles in the image should be uniformly distributed to avoid overlap between particles. This can be achieved by pouring a small amount of powder sample onto an adhesive attached to an SEM sample holder and blowing air to remove excess powder.

[0105] Polycrystalline grains form after the heat treatment step.

[0106] In a particular highly preferred embodiment, the positive electrode active material has a polycrystalline morphology.

[0107] Specific preferred embodiments relate to the positive electrode active material of the present invention, which comprises the powder including the polycrystalline particles, wherein the particles constituting the powder have a median D50 value of less than 15 μm, preferably less than 10 μm, more preferably less than 5 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the median D50 value of the particles is greater than 1 μm, preferably greater than 2 μm, more preferably greater than 3 μm. Specific preferred embodiments relate to the positive electrode active material of the present invention, wherein the median D50 value of the particles is between 1 and 15 μm, preferably between 2 and 10 μm, more preferably between 3 and 5 μm. Preferably, the positive electrode active material has a polycrystalline morphology.

[0108] Specific embodiments relate to the positive electrode active material of the present invention, which a. The powder comprises single particles and / or secondary particles; b. Having a Co content as measured by cross-sectional EDS (CS-EDS) at the edge of the particles. 边缘 Co 边缘Expressed as a mol% relative to the sum of Ni, Mn, and Co contents as measured by CS-EDS at the edge of the particle, wherein the particle has a Co content as measured by CS-EDS at the center of the particle. 中心 Co 中心 Expressed as a mol% relative to the sum of Ni, Mn, and Co contents, as measured by CS-EDS at the center of the particle, where the ratio of Co is... 边缘 / Co 中心 >1.10, preferably Co 边缘 / Co 中心 >1.20, more preferably Co 边缘 / Co 中心 >1.30, the most preferred Co 边缘 / Co 中心 >1.50; and / or c. Al content defined as c / (x+y+z+c) A Where c is the Al content as measured by XPS, and the positive electrode active material has an Al content of Al. B Al B It was determined by XPS analysis, in which Al B Expressed as the mole fraction relative to the total amounts of Co, Mn, Ni, and Al, as measured by XPS analysis, where the ratio of Al... B / Al A >1.0, preferably the ratio Al B / Al A >2.0, more preferably the ratio Al B / Al A >2.5, or even more preferably, the ratio of Al B / Al A >3.0, or even a more preferred ratio of Al B / Al A >3.5, the optimal ratio Al B / Al A >4.0.

[0109] Specific embodiments relate to a positive electrode active material according to the present invention, wherein a. is the powder comprising single particles and / or secondary particles, and b. Having a carbon content in the range of 100 ppm to 400 ppm based on the total weight of the positive electrode active material, preferably in the range of 150 ppm to 350 ppm based on the total weight of the positive electrode active material, and more preferably in the range of 200 ppm to 300 ppm based on the total weight of the positive electrode active material.

[0110] Specific preferred embodiments relate to a positive electrode active material according to the present invention, wherein a. is the powder comprising single particles and / or secondary particles, and b. Having a carbon absorption of less than 900 ppm carbon based on the total weight of the positive electrode active material, preferably less than 500 ppm carbon based on the total weight of the positive electrode active material, and more preferably less than 445 ppm carbon.

[0111] Specific preferred embodiments relate to a positive electrode active material according to the present invention, wherein a. is the powder comprising single particles and / or secondary particles, and b. Having a carbon absorption of less than 250% carbon by weight of the positive electrode active material, preferably less than 200% carbon by weight of the positive electrode active material, and more preferably less than 198% carbon by weight of the positive electrode active material.

[0112] Specific preferred embodiments relate to a positive electrode active material according to the present invention, wherein a. is the powder comprising polycrystalline particles, preferably a positive electrode active material having a polycrystalline morphology, and b. Having a carbon content in the range of 250 ppm to 1000 ppm based on the total weight of the positive electrode active material, preferably in the range of 300 ppm to 750 ppm based on the total weight of the positive electrode active material, and more preferably in the range of 400 ppm to 550 ppm based on the total weight of the positive electrode active material.

[0113] Specific preferred embodiments relate to a positive electrode active material according to the present invention, wherein a. is the powder comprising polycrystalline particles, preferably a positive electrode active material having a polycrystalline morphology, and b. Having a carbon absorption of less than 1600 ppm carbon by weight of the positive electrode active material, preferably less than 1500 ppm carbon by weight of the positive electrode active material, and more preferably less than 1450 ppm carbon by weight of the positive electrode active material.

[0114] Specific preferred embodiments relate to a positive electrode active material according to the present invention, wherein a. is a powder comprising the polycrystalline particles, preferably a positive electrode active material having a polycrystalline morphology, and b. Having a carbon absorption of less than 340% carbon by weight of the positive electrode active material, preferably less than 245% carbon by weight of the positive electrode active material, and more preferably less than 200% carbon by weight of the positive electrode active material.

[0115] method In a second aspect, the present invention provides a method for manufacturing a positive electrode active material, wherein the method comprises: Step a) Mixing the lithium transition metal-based oxide compound with a silicon source and a boron source, and Step b) Heat the mixture at a temperature below 500°C for a period of time between 1 hour and 20 hours to obtain the positive electrode active material.

[0116] In a highly preferred embodiment of the method for manufacturing the positive electrode active material of the present invention, the positive electrode active material is the positive electrode active material according to the first aspect of the present invention. As those skilled in the art will understand, if the method for manufacturing the positive electrode active material of the present invention yields the positive electrode material according to the first aspect of the present invention, then all embodiments relating to the positive electrode active material according to the first aspect of the present invention are applicable to necessary modifications to the method for manufacturing the positive electrode active material according to the first aspect of the present invention. For example, the relationship with Li, M', B as explained herein in the context of positive electrode active materials. A B B Si A Si B Various implementation schemes relating to the identity and amount of carbon content are equally applicable to methods for preparing the positive electrode active material.

[0117] In a preferred embodiment of the method, the lithium transition metal-based oxide compound comprises Li, M''', and oxygen, wherein M''' includes Ni, Mn, Co, and D''', and D''' is an element other than Li, Ni, Mn, and Co. Preferably, D''' is at least one element selected from the group consisting of: Al, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Sr, Ti, V, W, Y, Zn, Si, B, and Zr; preferably Al, Ti, Cr, Nb, S, Y, and W; more preferably Al, Ti, Nb, and W. Preferably, the lithium transition metal-based oxide used is typically prepared according to a lithiation method, which involves heating a mixture of a transition metal oxide precursor and an additional lithium source at a temperature preferably at least 500°C and at most 1000°C. Typically, transition metal oxide precursors are prepared by co-precipitation of one or more transition metal sources (such as salts of elemental Ni, Mn, and / or Co, preferably sulfates or nitrates, more preferably sulfates) in the presence of a basic compound (such as a basic hydroxide, for example, sodium hydroxide, and / or ammonia). Preferably, the additional lithium source is metallic lithium or a lithium salt, preferably a lithium salt, such as LiOH.

[0118] In a preferred embodiment, the lithium transition metal-based oxide compound comprises Li, M''', and oxygen, wherein M''' includes Ni, Mn, Co, and D''', wherein a. Ni with a content of x''' relative to M''', where 75.0 mol% ≤ x''' ≤ 92.0 mol%, preferably 78.0 mol% ≤ x''' ≤ 90.0 mol%, more preferably 80.0 mol% ≤ x''' ≤ 88.0 mol%, b. Mn with a content of y''' relative to M''', where 0.0 mol% < y''' ≤ 20.0 mol%, preferably 1.0 mol% ≤ y''' ≤ 15.0 mol%, more preferably 2.0 mol% ≤ y''' ≤ 10.0 mol%, c. Co with a content of z''' relative to M''', where 0.0 mol% < z''' ≤ 20.0 mol%, preferably 1.0 mol% ≤ z''' ≤ 15.0 mol%, more preferably 2.0 mol% ≤ z''' ≤ 10.0 mol%, d. D''' with a content of d''' relative to M''', where 0.0 mol% < d''' ≤ 1.75 mol%, preferably 0.25 mol% ≤ d''' ≤ 1.5 mol%, more preferably 0.5 mol% ≤ d''' ≤ 1.25 mol%, where D''' is an element different from Ni, Mn, Co, and oxygen; where x''', y''', z''', and d''' are measured by ICP - OES, and where x''' + y''' + z''' + d''' = 100.0 mol%.

[0119] In a preferred embodiment of the method, the silicon source is Si - alkoxide, alkylalkoxysilane, or polysiloxane, preferably alkylalkoxysilane or polysiloxane, more preferably polysiloxane.

[0120] In a preferred embodiment of the method, the silicon source is Si - alkoxide, preferably SiOR[[ID=十七]] 1 R 2 R 3 R 4 where R 1 、R 2 、R 3 and R 4 are independently selected from H and C1 - C8 alkyl or alkenyl optionally substituted by halogen, preferably C1 - C4 alkyl, more preferably C1 - C2 alkyl.

[0121] In a more preferred embodiment of the method, the silicon source is SiOR 5 4 of Si - alkoxide, where R 5 is C1 - C8 alkyl or alkenyl optionally substituted by halogen, preferably C1 - C4 alkyl, more preferably C1 - C2 alkyl. In a highly preferred case, the Si source is tetraethyl orthosilicate.

[0122] In a highly preferred embodiment of the method, the silicon source is an alkylalkoxysilane, more preferably R 6 a (R 7 O) b Si, where a = 0, 1, 2, or 3; b = 1, 2, or 3; a + b = 4; and R 6 and R 7 Independently selected from H and optionally halogen-substituted C1-C8 alkyl or alkenyl groups, preferably C1-C4 alkyl, more preferably C1-C2 alkyl; more preferably, R 6 and R 7 It is the same alkyl group selected from the group consisting of: optional C1-C8 alkyl or alkenyl groups substituted with halogen, preferably C1-C4 alkyl, more preferably C1-C2 alkyl; most preferably, the silicon source is methyltrimethoxysilane.

[0123] In a highly preferred embodiment, the silicon source is a polysiloxane, preferably a polydialkylsiloxane, wherein the alkyl group is selected from optional halogen-substituted C1-C8 alkyl or alkenyl groups, preferably C1-C4 alkyl, more preferably C1-C2 alkyl; more preferably polydimethylsiloxane. In a highly preferred embodiment, the silicon source is a polysiloxane, which is a hydroxyl-terminated polydimethylsiloxane or a trimethylsiloxy-terminated polydimethylsiloxane, preferably a hydroxyl-terminated polydimethylsiloxane. The invention is not limited to having a specific number-average molecular weight M. n Specific polydimethylsiloxanes. Such polymers are commercially available in a variety of different number-average molecular weights. Preferably, hydroxyl-terminated or trimethylsiloxy-terminated polydimethylsiloxanes have a number-average molecular weight M between 200 g / mol and 1,000,000 g / mol, preferably between 300 g / mol and 150,000 g / mol, most preferably between 400 g / mol and 10,000 g / mol, such as about 410 g / mol or 4200 g / mol. n .

[0124] In a particular preferred embodiment, the lithium transition metal-based oxide compound is mixed with a silicon source, especially when the silicon source is solid, by dry mixing the lithium transition metal-based oxide compound with the silicon source. As those skilled in the art will understand, dry mixing means not adding any additional solvent to the mixture of the lithium transition metal-based oxide compound and the silicon source.

[0125] In a particular preferred embodiment of the method, a silicon source is added to a first liquid, particularly when the silicon source is an alkylalkoxysilane as defined in this invention, preferably the silicon source is dissolved in the first liquid. Preferably, the first liquid is water. Preferably, a lithium transition metal-based oxide compound having a silicon source added to the first liquid is further mixed with a second liquid, preferably the second liquid comprising water and an alcohol, more preferably the second liquid being a mixture of water and an alcohol. Preferably, the alcohol is methanol, ethanol, propanol, butanol, or a mixture thereof, preferably methanol or ethanol, more preferably ethanol. In a preferred embodiment, the weight ratio of alcohol to water (meaning the total amount of water present in the first and second liquids) is between 10:1 and 1:10, preferably between 5:1 and 1:5, more preferably between 2:1 and 1:2.

[0126] In a preferred embodiment, the Si content in the silicon source is at least 0.01% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably at least 0.05% by weight, and more preferably at least 0.08% by weight. In a preferred embodiment, the Si content in the silicon source is at most 1.0% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably at most 0.5% by weight, and more preferably at most 0.22% by weight. In a preferred embodiment, the Si content in the silicon source is in the range of 0.01% to 1.0% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably in the range of 0.05% to 0.5% by weight, and more preferably in the range of 0.08% to 0.22% by weight.

[0127] In a preferred embodiment, mixing the lithium transition metal-based oxide compound with the boron source involves dry mixing the lithium transition metal-based oxide compound with the boron source, particularly when the boron source is solid. As those skilled in the art will understand, dry mixing means not adding any additional solvent to the mixture of the lithium transition metal-based oxide compound and the boron source.

[0128] In a preferred embodiment, the boron source is boric acid (H3BO3), boron oxide (B2O3), or borates such as sodium tetrahydroxyborate (NaB(OH)4), trisodium orthoborate (Na3BO3), sodium perborate (Na2H4B2O8), sodium metaborate (Na3B3O6), etc., and preferably the boron source is boric acid (H3BO3).

[0129] In a preferred embodiment, the boron content in the boron source is at least 0.01% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably at least 0.02% by weight, and more preferably at least 0.04% by weight. In a preferred embodiment, the boron content in the boron source is at most 1.0% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably at most 0.5% by weight, and more preferably at most 0.22% by weight. In a preferred embodiment, the boron content in the boron source is in the range of 0.01% to 1.0% by weight relative to the total weight of the lithium transition metal-based oxide compound, preferably in the range of 0.02% to 0.5% by weight, and more preferably in the range of 0.04% to 0.22% by weight.

[0130] In a preferred embodiment of the method, the heating temperature of the mixture is above 275°C, preferably above 300°C, and most preferably above 325°C. In a preferred embodiment of the method, the heating temperature of the mixture is below 450°C, preferably below 400°C, and more preferably below 375°C. In a preferred embodiment of the method, the heating temperature of the mixture is: a. Between 275°C and 450°C, preferably between 300°C and 400°C, more preferably between 325°C and 375°C.

[0131] In a preferred embodiment of the method, the mixture is heated for at least 2 hours, preferably at least 3 hours, more preferably at least 5 hours. In a preferred embodiment of the method, the mixture is heated for up to 15 hours, preferably up to 10 hours, more preferably up to 7 hours. In a preferred embodiment of the method, the mixture is heated for between 2 and 15 hours, preferably between 3 and 10 hours, more preferably between 5 and 7 hours.

[0132] In a more preferred embodiment of the method, the mixture is: a. Heating at a temperature between 275°C and 450°C, preferably between 300°C and 400°C, more preferably between 325°C and 375°C; and b. Heating for 2 to 15 hours, preferably between 3 and 10 hours, and more preferably between 5 and 7 hours.

[0133] A preferred embodiment of the method involves heating the mixture in an oxidizing atmosphere. Preferably, the oxidizing atmosphere contains oxygen, such as air, or is composed of oxygen.

[0134] In a more preferred embodiment, the heating of the mixture is carried out in a furnace under an oxidizing atmosphere.

[0135] Methods for characterizing products On the other hand, the present invention relates to positive electrode active materials obtainable by a method according to a second aspect of the invention. As those skilled in the art will understand, all embodiments relating to positive electrode active materials according to a first aspect of the invention and / or methods according to a second aspect of the invention are applicable to necessary modifications to positive electrode active materials obtainable by a method according to the invention. For example, the relationship between Li, M', and Si as explained herein in the context of positive electrode active materials or methods for manufacturing said positive electrode active materials. A Si B B B B A Various implementation schemes relating to the identity and quantity of silicon and boron sources are also applicable to positive electrode active materials that can be obtained by methods used to prepare positive electrode active materials.

[0136] Battery In another aspect, the present invention relates to a battery comprising a positive electrode active material according to a first aspect of the invention and / or a positive electrode active material obtainable by a method according to a third aspect of the invention.

[0137] In a preferred embodiment, the battery is a solid-state battery. Preferably, the solid-state battery comprises a sulfide-based electrolyte. More preferably, the electrolyte is a sulfide-based solid electrolyte, and more preferably, the electrolyte comprises Li, P, and S. Typically, the following sulfur-containing compounds can be suitably used: Li6PS5X, where X is F, Br, Cl, or I, preferably Br or Cl; thio-LISICON, a thio-ultrafast ion conductor (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-Li2S-P2O5, 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 Cl0.3 and / or Li7P3S 11 In a highly preferred embodiment, the battery is a sulfide solid-state battery.

[0138] 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.

[0139] In a preferred embodiment, the battery according to the invention preferably comprises a solid-state battery with a sulfide-based electrolyte as defined herein, having an efficiency of at least 88%, preferably at least 89%, more preferably at least 90%, even more preferably at least 91%, even more preferably at least 91.3%, even more preferably at least 92%, and most preferably at least 94%. As those skilled in the art will understand, the battery efficiency is defined, wherein the initial charge capacity (CQ1) and discharge capacity (DQ1) are between 4.3 V and 2.5 V (Li / Li + ) or 3.7 V to 1.9 V (In-Li / Li + The reversible capacity was measured in constant current mode (CC) at a C rate of 0.1 C within its voltage range. The efficiency (%) of the reversible capacity was derived from the following equation:

[0140] Preferably, the scheme uses a 1C current definition of 160 mA / g.

[0141] In a preferred embodiment, the battery according to the invention has an initial discharge capacity of at least 200.0 mAh / g, more preferably at least 205.0 mAh / g, even more preferably at least 209.0 mAh / g, even more preferably at least 210.0 mAh / g, and most preferably at least 212 mAh / g. As those skilled in the art will understand, the initial discharge capacity (DQ1) is measured in constant current mode (CC) at a C-rate of 0.1 C within the following voltage range: 4.3 V to 2.5 V (Li / Li + ) or 3.7 V to 1.9 V (InLi / Li + ).

[0142] use In another aspect, the present invention relates to the use of positive electrode active materials according to a first aspect of the invention and / or positive electrode active materials obtainable by a method according to a third aspect of the invention in batteries.

[0143] One preferred embodiment is the use of the positive electrode active material in a battery, preferably a solid-state battery, more preferably a sulfide solid-state battery, to improve the battery efficiency and / or increase the initial discharge capacity of the battery.

[0144] In another aspect, the present invention relates to the use of a battery according to a fourth aspect of the invention in any of a portable computer, tablet computer, mobile phone, energy storage system, electric vehicle or hybrid electric vehicle, preferably in an electric vehicle or hybrid electric vehicle.

[0145] Example The following analysis methods are used in the embodiments: Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES): The elemental contents of the cathode active materials described in the examples and comparative examples below were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) using an Agilent ICP 720-OES system. 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 suitable amount of solution was pipetted and transferred to a 250 mL volumetric flask for a second dilution, in which the volumetric flask was filled to the 250 mL mark with an internal standard and 10% hydrochloric acid and then homogenized. Finally, this solution was used for ICP-OES measurements. The contents of Ni, Mn, Co, B, and Si are expressed as the total atomic percent (%) of these contents.

[0146] Particle size: After dispersing the positive electrode active material powder 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.

[0147] Sulfide solid-state rechargeable battery cell testing Sulfide solid-state rechargeable battery cell fabrication Positive electrode preparation: For the preparation of the positive electrode, a slurry containing positive electrode active material powder, Li-PS-based solid electrolyte, carbon (Super-P, Timcal), and binder (RC-10, Arkema) (a mixture 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 an aluminum foil, and then the slurry-coated foil was dried in a vacuum oven to obtain the positive electrode. The resulting positive electrode was punched to a diameter of 10 nm, wherein the active material loading was approximately 4 mg / cm³. 2 .

[0148] Negative electrode preparation: For the preparation of the negative electrode, a Li foil (3 mm in diameter and 100 μm in thickness) is placed at the top center of an In foil (10 nm in diameter and 100 μm in thickness) and pressed to form a Li-In alloy negative electrode.

[0149] Separator preparation: In order to prepare a separator that also functions as a solid electrolyte in a battery, Li-PS-based solid electrolyte was pressed into a sheet with a thickness of 100 μm under a pressure of 250 MPa.

[0150] Battery cell assembly: Sulfide solid-state rechargeable batteries are assembled in an Ar-filled glove box, in the following order from bottom to top: positive electrode with Al current collector, where the coating is on top — separator — negative electrode with Li side on top — Cu current collector. The stacked components are pressed together under a pressure of 250 MPa and placed in an external cage to prevent exposure to air.

[0151] Test Method: The test method is a standard "constant cutoff voltage" test. Each battery cell was cycled at 60°C using a Toscat-3100 computer-controlled constant current cycling station (from Toyo).

[0152] The scheme uses a 1C current defined at 160 mA / g. Initial charge capacity (CQ1) and discharge capacity (DQ1) are between 4.3 V and 2.5 V (Li / Li + ) or 3.7 V to 1.9 V (In-Li / Li + The voltage range is measured at a C-rate of 0.1 C in constant current mode (CC). The efficiency (%) of the irreversible capacity is obtained according to the following equation: .

[0153] Exposure test: 40 grams of positive electrode active material were evenly spread in a 95 x 95 mm area. 2The plate was placed in a 30°C room for carbon exposure testing. The atmosphere of the room was controlled to have a relative humidity level of 50%. After 3 days (72 hours), the positive electrode active material powder was collected for carbon analysis as described in Method E. The increase in carbon content was calculated according to the following equation, where C 前 It is the carbon content before exposure, C 后 The carbon content after exposure:

[0154] Carbon Analysis: The carbon content of the cathode active material powder was measured using a Horiba Emia-Expert carbon / sulfur analyzer. One gram of cathode active material powder was placed in a ceramic crucible within a high-frequency induction furnace. 1.5 grams of tungsten and 0.2 grams of tin were added to the crucible as promoters. The powder was heated at a programmable temperature, during which the gases produced in the combustion process were analyzed using an infrared detector. The carbon concentration was determined by analyzing CO2 and CO.

[0155] 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.

[0156] For surface analysis of the cathode 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 survey scan was performed at a pass energy of 200 eV to identify elements present on the surface. After data collection, the C1s peak with maximum intensity (or center) at a binding energy of 284.8 eV was used as the calibration peak position. Subsequently, a precise narrow scan was performed at 50 eV, with at least 10 scans for each identified element to determine the precise surface composition.

[0157] Curve fitting was performed using Shirley-type background processing and Scofield sensitivity factor via CasaXPS version 2.3.19PR1.0. Fitting parameters are based on Table 1a. The linearity GL(30) is a Gaussian / Lorentz product formula, where 70% is a Gaussian line and 30% is a Lorentz line.

[0158] Table 1a. XPS fitting parameters for Ni2p3, Mn2p3, Co2p3, B1s and Si1p.

[0159]

[0160] For the Ni and Co peaks, constraints are set for each defined peak according to Table 1b.

[0161] Table 1b. XPS fitting constraints for Ni and Co peak fitting.

[0162]

[0163] The surface content of B and Si, as determined by XPS, is expressed as the atomic fractions of B and Si in the particle surface layer divided by the total content of Ni, Mn, Co, B, and Si in the surface layer. The calculation method is as follows: a. Atomic ratios of B to Ni, Mn, Co, Si, and B determined by XPS

[0164] b. Atomic ratios of Si to Ni, Mn, Co, B, and Si determined by XPS

[0165] The present invention is further illustrated in the following embodiments: Comparative Example CEX1.1: Polycrystalline cathode active material was prepared according to the following steps: Step 1) Preparation of transition metal oxide hydroxide precursors: Ni with metallic composition is 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. 0.85 Mn 0.07 Co 0.08 Nickel-based transition metal oxide hydroxide powder (TMH1).

[0166] Step 2) Mixing: The TMH1 prepared in step 1) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal (Ni, Mn and Co) molar ratio of 0.98.

[0167] Step 3) Heating: The first mixture from Step 2) was heated at 785°C for 10 hours in an oxidizing atmosphere to obtain CEX1.1 containing Ni, Mn, and Co, with a Ni:Mn:Co molar ratio of 0.85:0.07:0.08, which was obtained by ICP-OES. CEX1.1 has a D50 of 4 μm.

[0168] The SEM image of CEX1.1 is shown in Figure 2 middle.

[0169] Comparative example CEX1.2 was prepared by mixing 100 g of CEX1.1 with 0.43 g of SiO2 powder and 0.57 g of H3BO3 powder in an industrial blender, followed by heating at 350°C for 6 hours under an oxygen flow.

[0170] Comparative example CEX1.3 was prepared by mixing 400 g of CEX1.1 with 2.12 g of hydroxyl-terminated polydimethylsiloxane (PDMS-O) in an industrial blender, followed by heating at 350°C for 6 hours under an oxygen flow. PDMS-O is a liquid with a molecular weight of approximately 4200 g / mol.

[0171] Comparative example CEX1.4 was prepared by mixing 400 g of CEX1.1 with 2.29 g of H3BO3 in an industrial blender and then heating at 350°C for 6 hours under an oxygen flow.

[0172] Examples EX1.1, EX1.2, EX1.3, EX1.4, and EX2 are based on the present invention.

[0173] EX1.1 was prepared by mixing 400 g of CEX1.1 with 2.12 g of PDMS-O and 1.14 g of H3BO3 in an industrial blender, followed by heating at 350°C for 6 hours under an oxygen flow.

[0174] EX1.2 was prepared using the same method as EX1.1, except that the amount of H3BO3 added was 2.29 g.

[0175] EX1.3 was prepared using the same method as EX1.1, except that 4.57 grams of H3BO3 were added.

[0176] EX1.4 was prepared using the same method as EX1.2, except that the amount of PDMS-O added was 1.06 g.

[0177] Comparative Example CEX2.1: A positive electrode active material powder containing single particles and secondary particles was prepared according to the following steps: Step 1) Preparation of transition metal oxide hydroxide precursors: Ni with metallic composition is 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. 0.85 Mn 0.07 Co 0.08 Nickel-based transition metal oxide hydroxide powder (TMH2).

[0178] Step 2) Precursor oxidation: The TMH1 prepared in step 1) is heated at 400°C for 7 hours in an oxidizing atmosphere to obtain the heated product.

[0179] Step 3) First mixing: The heated product prepared in step 2) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal (Ni, Mn and Co) molar ratio of 0.96.

[0180] Step 4) First heating: The first mixture from step 3) is heated at 890°C for 11 hours in an oxidizing atmosphere to obtain the first heated product.

[0181] Step 5) Wet bead milling: The product from the first heating in step 4) is bead milled in a solution containing 0.5 mol% Co relative to the total molar content of Ni, Mn, and Co in the first heating product, followed by drying and sieving to obtain the milled product. The weight ratio of solid to solution in the bead mill is 6:4 and the process lasts for 20 minutes.

[0182] Step 6) Second mixing: The milled product obtained in step 5) is mixed in an industrial blender with 1.5 mol% Co from Co3O4 and 7.5 mol% Li from LiOH, which are respectively relative to the total molar content of Ni, Mn and Co in the milled product, to obtain a second mixture.

[0183] Step 7) Second heating: The second mixture from step 6) is heated at 760°C for 10 hours in an oxidizing atmosphere, and then pulverized and sieved together with 250 ppm of alumina powder relative to the weight of the second mixture to obtain the second heated powder.

[0184] Step 8) Third mixing: Mix 400g of the second heated powder obtained from step 7) with 2.12g of PDMS-O in an industrial blender to obtain a third mixture.

[0185] Step 9) Third heating: The third mixture obtained from step 8) is heated at 350°C for 6 hours under an oxygen flow, then ground and sieved.

[0186] Comparative example CEX2.1 contains Ni, Mn, and Co, with a Ni:Mn:Co molar ratio of 0.84:0.07:0.09, obtained by ICP-OES. CEX2.1 has a D50 of 4 μm.

[0187] Due to the wet milling in step 5), CEX2.1 is a powder containing both single and secondary particles. SEM images of CEX2.1 are shown below. Figure 3 middle.

[0188] Comparative example CEX2.2 was prepared according to the same method as CEX2.1, except that 2.29 g of H3BO3 was added instead of PDMS-O in step 8).

[0189] EX2 was prepared using the same method as CEX2.1, except that 2.29 g of H3BO3 was added together with PDMS-O in step 8).

[0190] result Table 2a. Summary of the procedures and properties of the embodiments and comparative examples.

[0191]

[0192] Table 2b Summary of the processes and properties of the embodiments and comparative examples - continued

[0193] Table 3. Summary of XPS Quantification in Examples and Comparative Examples

[0194] Tables 2a and 2b, and Table 3 summarize the preparation processes and properties of the examples and comparative examples, with the main changes being in morphology, Si source, B content, and Si content. In XPS analysis, B content above 0... B or Si B The values ​​indicate that B or Si is present on the surface of the positive electrode active material, which is correlated with XPS measurements obtained from the first few nanometers (e.g., 1 nm to 10 nm) of the topmost (i.e., surface layer) of the sample. On the other hand, B from ICP-OES measurements... A or Si A This represents the total B or Si content of the particle. Therefore, a ratio higher than 1 in XPS results to ICP-OES results, such as B... B / B A or Si B / Si A This indicates that the B or Si is mainly present on the surface of the positive electrode active material. Higher B content... B / B A or Si B / Si A The value corresponds to the presence of more B or Si on the surface of the positive electrode active material.

[0195] CEX1.3 is a cathode active material containing approximately 2000 ppm Si from PDMS-O, and CEX1.4 contains 1000 ppm B. When both materials are compared with EX1.2 (which is a cathode active material containing approximately 2000 ppm Si from PDMS-O and 1000 ppm B), EX1.2 exhibits improved electrochemical properties indicated by higher DQ1 and EF values. Regardless of morphology, the same improvement was observed for EX2 when compared with CEX2.1 and CEX2.2.

[0196] However, when the Si source is SiO2, as shown in Comparative Example CEX1.2, no improvement was observed despite the same amount of Si and B in the positive electrode active material. The better performance of EX1.2 may be due to the higher Si content. B / Si ARatio values. The changes in Si and B amounts in EX1.1, EX1.3, and EX1.4 further confirm the benefits of cathode active materials containing both B and Si. Furthermore, Table 3 shows, through the shift in the Si binding energy peak, that the chemical state and surrounding environment of Si in CEX1.2 differ from those in the examples prepared with PDMS-O.

[0197] Furthermore, for cathode active materials containing both Si and B, lower carbon levels were observed after a 3-day exposure test.

Claims

1. A positive electrode active material for a battery, the positive electrode active material comprising lithium, oxygen, nickel, and at least one metal selected from the group consisting of manganese and cobalt, comprising: a. Ni in an amount of x’ relative to the sum of Ni, Mn, and Co, wherein 40.0 < x’ < 98.0 mol%, b. Mn in an amount of y’ relative to the sum of Ni, Mn, and Co, wherein 0.0 < y’ < 30.0 mol%, c. Co in an amount of z’ relative to the sum of Ni, Mn, and Co, wherein 0.0 < z’ < 30.0 mol%, wherein x’, y’, and z’ are measured by ICP-OES, and wherein the positive electrode active material further comprises a content of boron B B wherein B B is expressed as a mole fraction of B relative to the total amount of Ni, Mn, Co, Si and B as measured by XPS analysis, wherein B B >0.30, wherein the positive electrode active material further comprises silicon, wherein the positive electrode active material shows a peak of binding energy level between 101.4 eV and 106.0 eV as measured by XPS analysis.

2. The positive electrode active material according to claim 1, wherein the positive electrode active material shows a peak of binding energy level between 101.4 eV and 105.0 eV, preferably between 101.5 eV and 104.5 eV, more preferably between 101.6 eV and 104.0 eV as measured by XPS analysis.

3. The positive electrode active material according to claim 1 or 2, having a content of Si B , where Si B is the mole fraction of Si relative to the total amount of Ni, Mn, Co, Si and B as measured by XPS analysis, and wherein Si B >0.

01.

4. The positive electrode active material according to claim 3, wherein Si B in the range of 0.03 to 1.0, preferably Si B in the range of 0.05 to 0.3, more preferably Si B in the range of 0.08 to 0.

2.

5. The positive electrode active material according to any one of the preceding claims, wherein B B in the range of 0.35 to 5.0, preferably B B in the range of 0.4 to 2.0, more preferably B B in the range of 0.68 to 1.

0.

6. The positive electrode active material according to any one of the preceding claims, comprising Li, M’, and oxygen, wherein M’ comprises: a. Ni in an amount of x relative to M’, wherein 50.0 < x < 98.0 mol%, b. Mn in an amount of y relative to M’, wherein 0.0 < y < 30.0 mol%, c. Co in an amount of z relative to M’, wherein 0.0 < z < 30.0 mol%, d. Si in an amount of a relative to M’, wherein 0.0 < a < 5.0 mol%, e. B in an amount of b relative to M’, wherein 0.0 < b < 5.0 mol%, f. D in an amount of d relative to M’, wherein 0.0 < d < 2.0 mol%, wherein D is an element different from Li, Ni, Mn, Co, Si, B, and oxygen, wherein x, y, z, a, b, and d are measured by ICP-OES, and wherein x + y + z + a + b + d is 100.0 mol%.

7. The positive electrode active material according to any one of the preceding claims, wherein the positive electrode active material has a Si content Si defined as a / (x+y+z+a+b) of 0.01 to 0.

20. A wherein the ratio Si B / Si A > 30.

0.

8. The positive electrode active material according to any one of the preceding claims, wherein the positive electrode active material has a B content B defined as b / (x+y+z+a+b) of 0.001 to 0.

1. A wherein the ratio B B / B A > 30.

0.

9. The positive electrode active material according to any one of claims 6 to 8, comprising: a. Ni in an amount of x relative to M’, wherein 75.0 mol% < x < 92.0 mol%, preferably 78.0 mol% < x < 90.0 mol%, more preferably 80.0 mol% < x < 88.0 mol%, b. Mn in an amount of y relative to M’, wherein 0.0 mol% < y < 20.0 mol%, preferably 1.0 mol% < y < 15.0 mol%, more preferably 2.0 mol% < y < 10.0 mol%, c. Co in an amount of z relative to M’, wherein 0.0 mol% < z < 20.0 mol%, preferably 1.0 mol% < z < 15.0 mol%, more preferably 2.0 mol% < z < 10.0 mol%, d. Si in an amount a relative to M', wherein 0.01 mol% < a < 2.0 mol%, preferably 0.03 mol% < a < 1.0 mol%, more preferably 0.06 mol% < a < 0.1 mol%, e. B in an amount b relative to M', wherein 0.01 mol% < b < 4.0 mol%, preferably 0.1 mol% < b < 3.0 mol%, more preferably 0.4 mol% < b < 2.0 mol%, f. D in an amount d relative to M', wherein 0.0 mol% < d < 1.75 mol%, preferably 0.25 mol% < d < 1.5 mol%, more preferably 0.5 mol% < d < 1.25 mol%.

10. The positive electrode active material according to any one of the preceding claims, wherein the positive electrode active material is a powder of single particles and / or secondary particles, wherein each of the single particles consists of only one primary particle and each of the secondary particles consists of at least two primary particles and at most twenty primary particles, as observed in SEM images.

11. The positive electrode active material according to claim 10, wherein at least 30% of the particles, more preferably at least 50% of the particles, constituting the powder, as observed in SEM images, are the single particles and / or the secondary particles.

12. The positive electrode active material according to any one of claims 1 to 10, wherein the positive electrode active material is a powder comprising polycrystalline particles, wherein each of the polycrystalline particles consists of more than 20 primary particles, as observed in SEM images.

13. The positive electrode active material according to any one of the preceding claims, having a carbon uptake of less than 340% carbon by total weight of the positive electrode active material, preferably a carbon uptake of less than 245% carbon by total weight of the positive electrode active material, more preferably a carbon uptake of less than 200% carbon, wherein the carbon uptake is measured by the exposure test.

14. A method for manufacturing a positive electrode active material, preferably according to any one of claims 1 to 13, wherein the method comprises: step a) mixing a lithium transition metal-based oxide compound with a silicon source and a boron source, and step b) heating the mixture at a temperature below 500 °C for a time between 1 hour and 20 hours, so as to obtain the positive electrode active material, wherein the Si source is a Si-alkoxide, an alkylalkoxysilane or a polysiloxane, preferably a polysiloxane, more preferably a hydroxyl-terminated polysiloxane.

15. The method according to claim 14, wherein the boron source is boric acid (H3BO3), boron oxide (B2O3), sodium tetrahydroxyborate (NaB(OH)4), trisodium orthoborate (Na3BO3), sodium perborate (Na2H4B2O8), sodium metaborate (Na3B3O6) or a combination thereof, preferably the boron source is boric acid (H3BO3).

16. A solid-state battery comprising the positive electrode active material according to any one of claims 1 to 13.

17. The solid-state battery of claim 16, comprising a sulfide-based solid electrolyte.

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