Lithium nickel-based composite oxide as a positive electrode active material for a rechargeable solid lithium-ion battery

Abstract

The present invention relates to a lithium nickel-based composite oxide comprising tungsten-containing lithium nickel-based oxide particles as a positive electrode active material for rechargeable lithium ion batteries suitable for electric vehicle and hybrid electric vehicle applications.

Description

Technical Field

[0001] Background Art The present invention relates to a lithium nickel-based composite oxide as a positive electrode active material for a rechargeable lithium-ion battery suitable for electric vehicle (EV) and hybrid electric vehicle (HEV) applications, which contains lithium nickel-based oxide particles containing tungsten (W).

[0002] The positive electrode active material is defined as a material that is electrochemically active in the positive electrode. It should be understood that the active material is a material that can capture and release Li ions when exposed to a voltage change over a predetermined time.

[0003] In the framework of the present invention, atomic % means atomic percentage. Atomic % or "atomic percent" as an expression of the concentration of a given element means what percentage of all the atoms in the compound are atoms of that element. The notation of atomic % is equivalent to mol %.

[0004] The use of a W-coated positive electrode material for a rechargeable solid battery was studied by Lim, C.B. and Park, Y.J. in Sci Rep 10, 10501 (2020).

[0005] However, when this positive electrode active material containing W is applied to a solid battery, the leakage capacity (Q total ) is large.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a positive electrode active material having an improved Q total in a solid battery, preferably in a rechargeable solid lithium-ion battery obtained by the method of the present invention.

Means for Solving the Problems

[0007] A cathode active material for a solid battery, the cathode active material containing Li, M', and oxygen, where M' is Ni with a content x of 50.0 mol% to 95.0 mol% with respect to M', Co with a content y of 0.0 mol% to 40.0 mol% with respect to M', Mn with a content z of 0.0 mol% to 70.0 mol%, preferably 0.0 mol% to 40.0 mol% with respect to M', W with a content w of 0.05 mol% to 2.0 mol%, Al with a content v of 0.1 mol% to 3.0 mol%, F with a content f of less than 2.0 mol%, Q with a content q of less than 3.0 mol% with respect to the total atomic content of M', where Q contains at least one element from the group consisting of B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, and Zn, x, y, z, v, w, and q are measured by ICP, f is measured by IC, (x + y + z + v + w + f + q) = 100.0 mol%, The cathode active material has a ratio Al B / v > 25.0, preferably Al B / v > 50.0, and W B / w > 5.0, preferably W B / w > 10.0, Al B and W B are determined by XPS analysis, and Al B and W B are expressed as mol% compared to the total of Ni, Co, Mn, Al, W, and F measured by XPS analysis, achieved by the cathode active material.

[0008] Such a material has improved electrochemical properties, and in particular, capacity leakage at higher temperatures is significantly reduced.

[0009] Preferably Al B / v > 60.0, more preferably AlB / v is 70.0.

[0010] Preferably, Al B / v < 250.0, and more preferably Al B / v < 200.0.

[0011] In a specific preferred embodiment, Alb / v is 60 to 250, preferably 70 to 200, more preferably 80 to 135.

[0012] Preferably, W B / w > 21.0, and more preferably W B / w > 22.0.

[0013] Preferably, W B / w < 150.0, and more preferably W B / w < 100.0.

[0014] In a specific preferred embodiment, Wb / w is 21.0 to 150.0, preferably 22.0 to 100.0, more preferably 30.0 to 50.0.

[0015] A specific preferred embodiment is a positive electrode active material of the present invention in which, with respect to M', the content x of Ni is 55.0 mol% ≤ x ≤ 75.0 mol%, preferably 60.0 mol% ≤ x ≤ 70.0 mol%, more preferably 62.0 mol% ≤ x ≤ 68.0 mol%.

[0016] A specific preferred embodiment is a positive electrode active material of the present invention in which the content x of Ni is 75.0 mol% ≤ x ≤ 95.0 mol%, preferably 80.0 mol% ≤ x ≤ 90.0 mol%, more preferably 80.0 mol% ≤ x ≤ 85.0 mol% with respect to M'.

[0017] As would be understood by those skilled in the art, the amounts of Li and M' in the positive electrode active material, preferably Li, Ni, Mn, Co, W, Al and Q, are measured by inductively coupled plasma (ICP). For example, without limiting the present invention, Agilent ICP720-ES is used in ICP analysis. In the framework of the present invention, the "atomic content" or "atomic %" of a given element representing the concentration means what percentage of all the atoms in the compound are atoms of that element. The notation mol% is equivalent to "mole percent" or "atomic %".

[0018] In a preferred embodiment, the content z of M is 0.0 mol% < z ≦ 40.0 mol%, preferably 3.0 mol% ≦ z ≦ 20.0 mol%, more preferably 5.0 mol% ≦ z ≦ 10.0 mol%.

[0019] In a preferred embodiment, the content y of Co is 0.0 mol% < z ≦ 40.0 mol% with respect to M', preferably 3.0 mol% ≦ z ≦ 20.0 mol%, more preferably 5.0 mol% ≦ z ≦ 10.0 mol%.

[0020] In a preferred embodiment, the content w of W is 0.05 mol% to 2.0 mol% with respect to M', preferably 0.1 mol% to 1.0 mol% with respect to M', more preferably 0.2 mol% to 0.5 mol%.

[0021] In a preferred embodiment, the content v of Al is 0.1 mol% to 3.0 mol% with respect to M', preferably 0.2 mol% to 1.5 mol% with respect to M', more preferably 0.3 mol% to 0.5 mol%.

[0022] In a preferred embodiment, the content f of F is less than 2.0 mol% with respect to M', preferably less than 1.5 mol% with respect to M', more preferably less than 1.2 mol%. In a preferred embodiment, the content f of F is greater than 0.0 mol% with respect to M', preferably greater than 0.5 mol% with respect to M', more preferably greater than 0.8 mol%. In a specific preferred embodiment, f = 0.0 mol% with respect to M'. As will be understood by those skilled in the art, the amount of f is determined by ion chromatography (IC) analysis. For example, although not limiting the present invention, Dionex ICP-2100 (Thermo scientific) is used in ICP-IC analysis.

[0023] In a preferred embodiment, the content q of Q is less than 3.0 mol% with respect to the total atomic content of M'. In a preferred embodiment, the content q of Q is less than 2.0 mol% with respect to M', preferably less than 1.0 mol%. In a preferred embodiment, the content q of Q is more than 0.0 mol% with respect to the total atomic content of M'. In a preferred embodiment, the content q of Q is more than 0.5 mol% with respect to M', preferably more than 0.8 mol% with respect to M'. In a specific preferred embodiment, the content of Q is q = 0.0 mol% with respect to M'.

[0024] In a preferred embodiment, f > 0, and the cathode active material has a ratio F B / f > 10.0, preferably F B / f > 12.0, more preferably F B / f > 14.0, where F B is determined by XPS analysis, and F B is expressed as mol% compared to the total of Ni, Co, Mn, Al, W, and F measured by XPS analysis. In a preferred embodiment, f > 0, and the cathode active material has a ratio F B / f < 30.0, preferably F B / f < 20.0, more preferably F B / f < 17.0, where F B is determined by XPS analysis, and F BIt is expressed as mol% compared with the total of Ni, Co, Mn, Al, W and F measured by XPS analysis. In a preferred embodiment, f > 0, and the cathode active material has a ratio F of 10.0 to 20, preferably 12.0 to 17.0, more preferably 14.0 to 16.0 B / f, and F B is determined by XPS analysis, and F B is expressed as mol% compared with the total of Ni, Co, Mn, Al, W and F measured by XPS analysis.

[0025] Specifically, Al B , W B and F B are the average molar fractions of Al, W and F measured in the region defined between the first point on the outer edge of the particle of the cathode material powder according to the present invention and the second point at a distance from the first point, respectively. The distance separating the first point and the second point is equal to the penetration depth of the XPS, and the penetration depth D is 1.0 to 10.0 nm. In particular, the penetration depth is the distance along the axis perpendicular to the virtual line that touches the outer edge and passes through the first point.

[0026] The outer edge of the particle is, within the framework of the present invention, the boundary or outer limit that distinguishes the particle from its external environment.

[0027] In a preferred embodiment, the cathode active material according to the first aspect includes secondary particles containing two or more primary particles.

[0028] In another preferred embodiment, the cathode active material according to the first aspect includes single crystal particles.

[0029] In a specific preferred embodiment, the particle is considered to be single crystal when it consists of only one crystal grain or at most 5, preferably at most 3 (three) constituent crystal grains observed by SEM or TEM, preferably by observing the grain boundaries.

[0030] In the context of the present invention, a grain boundary is defined as the interface between two grains within a particle. Preferably, the atomic planes of two crystallites are aligned in different orientations and intersect as a discontinuous plane of the crystal.

[0031] As will be understood by those skilled in the art and in the context of the present invention, the positive electrode active material has at least 45 μm × at least 60 μm (i.e., at least 2700 μm 2 ) in the field of view of SEM images, preferably at least 100 μm × 100 μm (i.e., at least 10,000 μm 2 ) and contains single crystal particles in which 80% or more of the particles are single crystals.

[0032] In the determination of single crystal particles, crystallites having a maximum linear dimension observed by SEM that is less than 20% of the median particle diameter D50 of the particles determined by laser diffraction are ignored. This avoids inadvertently considering particles that are essentially single crystals but may have some very small other crystallites deposited thereon as not being single crystals.

[0033] In certain preferred embodiments of the present invention and in the context of the present invention, the single crystal particles are monolithic particles. As will be understood by those skilled in the art, in these particular preferred embodiments, all embodiments regarding single crystal particles are equally applicable to monolithic particles.

[0034] In another preferred embodiment, the positive electrode active material according to the first aspect contains polycrystalline particles. As will be understood by those skilled in the art, polycrystalline particles are aggregates of 5 or more single crystal particles, preferably 10 or more single crystal particles, more preferably 50 or more single crystal particles. This can be observed by observing grain boundaries with an appropriate microscopy technique such as a Scanning Electron Microscope (SEM). The aggregation of single crystal particles into polycrystalline particles occurs under a post-treatment process such as a heat treatment process.

[0035] In a preferred embodiment, Q contains at least one element from the group consisting of B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, and Zr. Preferably, Q is at least one element from the group consisting of B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, and Zr. More preferably, Q is at least one element from the group consisting of B, Cr, Nb, S, Si, Ti, Y, and Zr. Most preferably, Q is Zr.

[0036] The present invention further relates to a positive electrode for a rechargeable lithium-ion battery, which contains the positive electrode active material according to the present invention defined above.

[0037] Preferably, the present invention provides a polymer cell for a rechargeable lithium-ion battery, which contains the positive electrode active material according to the first embodiment.

[0038] The present invention further relates to a polymer cell for a rechargeable lithium-ion battery, which contains the positive electrode active material according to the present invention defined above.

[0039] The present invention further relates to a rechargeable lithium-ion battery, which contains the positive electrode active material according to the present invention defined above.

[0040] The present invention further relates to a method for manufacturing a positive electrode active material for a solid battery, comprising: a step of preparing a lithium transition metal-based oxide compound; a step of mixing the lithium transition metal-based oxide compound with an Al source and a W source to obtain a mixture; a step of heating the mixture in an oxidation atmosphere in a furnace at a temperature of 250°C to less than 500°C, preferably at most 450°C, for a time of 1 hour to 20 hours to obtain the positive electrode active material powder. The present invention relates to a method including these consecutive steps.

[0041] In a preferred embodiment of the present method, the lithium transition metal-based oxide compound contains Li, M', and oxygen, and M' contains Ni, Mn, Co, and Q.

[0042] Preferably, the lithium transition metal oxide compound used is also typically prepared according to a lithiation process, i.e., a process of heating a mixture of a transition metal precursor and a lithium source preferably at a temperature of at least 500 °C. Typically, the transition metal precursor is prepared by coprecipitation of one or more transition metal sources, such as salts of M' elements Ni, Mn and / or Co, preferably sulfates, in the presence of an alkali compound, such as an alkali hydroxide, such as sodium hydroxide and / or ammonia.

[0043] Preferably, the lithium transition metal oxide compound is mixed with an additional F source to obtain a mixture.

[0044] Preferably, the positive electrode active material is the positive electrode active material according to the present invention defined above.

[0045] As will be understood by those skilled in the art, the Al B / v ratio can be increased or decreased, for example, by mixing more or less amounts of an Al source with the lithium transition metal oxide compound, respectively.

[0046] As will be understood by those skilled in the art, the W B / w ratio can be increased or decreased, for example, by mixing more or less amounts of a W source with the lithium transition metal oxide compound, respectively.

[0047] As will be understood by those skilled in the art, the F B / v ratio can be increased or decreased, for example, by mixing more or less amounts of an F source with the lithium transition metal oxide compound, respectively.

[0048] The present invention further relates to a method for manufacturing a polymer cell for a rechargeable solid lithium ion battery, the method comprising A step of preparing a solid polymer electrolyte membrane by mixing a first polyethylene oxide having a molecular weight of less than 1,500,000 g / mol and more than 500,000 g / mol with a lithium salt in a non-aqueous solvent; A step of preparing a positive electrode by mixing a second polyethylene oxide, a lithium salt, a positive electrode active material, and a conductive material powder in a non-aqueous solvent, wherein the second polyethylene oxide has a molecular weight of less than 300,000 g / mol and more than 50,000 g / mol; A step of preparing a negative electrode containing lithium metal; Assembling a solid polymer electrolyte membrane, a positive electrode, and a negative electrode to form a polymer cell for a rechargeable solid battery.

[0049] Preferably, the positive electrode active material is the positive electrode active material according to the present invention defined above.

[0050] The polymer cell manufactured according to the present invention is particularly suitable for reliable tests of electrochemical properties.

[0051] As further guidance, in order to better understand the teachings of the present invention, drawings are included. The drawings are intended to assist in the description of the present invention and are not intended to limit the invention disclosed herein. The figures and symbols included therein have meanings generally understood by those skilled in the technical field to which the present invention pertains.

Brief Description of the Drawings

[0052]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0053] To enable the implementation of the present invention, in the drawings and the following embodiments for carrying out the invention, preferred embodiments are described. The present invention is described with reference to these specific preferred embodiments, but the present invention includes numerous alternatives, modifications, and equivalents that will be apparent from consideration of the following embodiments for carrying out the invention and the accompanying drawings.

[0054] A) Inductively coupled plasma (ICP) analysis The amounts of Li, Ni, Mn, Co, Al, B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, W, and Zr in the positive electrode active material powder are measured using the inductively coupled plasma (ICP) method by using Agillent ICP720-ES (Agilent Technologies, https: / / www.agilent.com / cs / library / brochures / 5990-6497EN%20720-725_ICP-OES_LR.pdf). A 2-gram powder sample is dissolved in 10 mL of high-purity hydrochloric acid (at least 37 wt% HCl with respect to the total weight of the solution) in an Erlenmeyer flask. The flask is covered with glass and heated on a hot plate at 380 °C until the precursor is completely dissolved. After cooling to room temperature, the solution in the Erlenmeyer flask is poured into a 250-mL volumetric flask. Then, the 250-mL volumetric flask is filled with deionized water up to the 250-mL calibration mark and subsequently homogenized. An appropriate amount of the solution is taken out with a pipette, transferred to a 250-mL volumetric flask for a second dilution, and after filling the 250-mL volumetric flask with an internal standard substance and 10% hydrochloric acid up to the 250-mL calibration mark, it is homogenized. Finally, this 50-mL solution is used for ICP measurement.

[0055] B) Ion chromatography (IC) analysis The amount of F in the positive electrode active material powder is measured by ion chromatography (IC) method using Dionex ICS-2100 (Thermo scientific). Immediately before use, a 250 mL volumetric flask and a 100 mL volumetric flask are rinsed with a mixed solution of 65 wt% HNO3 and deionized water in a volume ratio of 1:1, and then the flasks are rinsed with deionized water at least 5 times. 2 mL of HNO3, 2 mL of H2O2, and 2 mL of deionized water are mixed as a solvent. 0.5 gram of the powder sample is dissolved in the mixed solvent. The solution is completely transferred from the container to a 250 mL volumetric flask, and the 250 mL volumetric flask is filled with deionized water up to the calibration line. The filled flask is shaken well to ensure the homogeneity of the solution. 9 mL of the solution is transferred from the 250 mL flask to a 100 mL volumetric flask. The 100 mL volumetric flask is filled with deionized water up to the 100 mL calibration line, and the diluted solution is shaken well to obtain a homogeneous sample solution. 2 mL of the sample solution is inserted into a 5 mL IC vial through a syringe ion guard cartridge for IC measurement.

[0056] C) Scanning Electron Microscope (SEM) Analysis The morphology of the positive electrode active material is analyzed by scanning electron microscope (SEM) technology. The measurement is carried out at 25 °C under a high vacuum environment of 9.6×10 -5 Pa using JEOL JSM 7100F (https: / / www.jeolbenelux.com / JEOL-BV-News / jsm-7100f-thermal-field-emission-electron-microscope).

[0057] D) X-ray Photoelectron Spectroscopy (XPS) Analysis In the present invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of the positive electrode active material powder particles. In XPS measurement, the signal is obtained from the top of the sample, that is, the first few nanometers (e.g., 1 nm to 10 nm) of the surface layer. Therefore, all the elements measured by XPS are contained in the surface layer.

[0058] For the surface analysis of the positive electrode active material powder particles, XPS measurements are performed using a Thermo K-α+ spectrometer (Thermo Scientific, https: / / www.thermofisher.com / order / catalog / product / IQLAADGAAFFACVMAHV). Monochromatic Al Kα radiation (hv = 1486.6 eV) is used with a spot size of 400 μm and a measurement angle of 45°. A broad survey scan for identifying the elements present on the surface is carried out at a pass energy of 200 eV. The C1s peak having the maximum intensity (or center) at a binding energy of 284.8 eV is used as the calibration peak position after data collection. Thereafter, for each identified element, an accurate narrow scan is scanned at least 10 times at 50 eV to determine the accurate surface composition.

[0059] Curve fitting is performed by CasaXPS version 2.3.19PR1.0 (Casa Software, http: / / www.casaxps.com / ) using Shirley-type background processing and Scofield sensitivity coefficients. The fitting parameters follow Table 1a. The line shape GL(30) is the Gaussian / Lorentz product formula for a 70% Gaussian line and 30% Lorentz line. LA(α, β, m) is an asymmetric line shape, where α and β define the tail spread of the peak and m defines the width.

[0060]

Table 1

[0061] For the Al peak within the fitting range of 64.1 ± 0.1 eV to 78.5 ± 0.1, constraints are set for each peak defined according to Table 1b. The Ni3p peak is not included in the quantification.

[0062]

Table 2

[0063] The surface contents of Al, W, and F determined by XPS are represented as the molar percentages of Al, W, and F in the particle surface divided by the total content of Ni, Mn, Co, Al, W, and F in the surface. They are calculated as follows.

[0064]

Number

[0065] E) Polymer solid test E1) Preparation of polymer solid battery E1-1) Manufacture of solid polymer electrolyte (SPE) A solid polymer electrolyte (SPE) is prepared according to the following method. Step 1) In 99.8 wt% anhydrous acetonitrile (Aldrich), polyethylene oxide (PEO, 1,000,000 g / mol, Alfa Aesar) and lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI, over 98.0%, TCI) are mixed at 2000 revolutions per minute (rpm) using a mixer for 30 minutes. The mass ratio of polyethylene oxide to LiTFSI is 3.0. Step 2) The mixture from Step 1 is poured into a Teflon dish and dried at 25 °C for 12 hours. Step 3) The dried SPE is removed from the dish, and the dried SPE is punched out to obtain an SPE disk with a thickness of 300 μm and a diameter of 19 mm.

[0066] E1-2) Preparation of positive electrode The positive electrode is prepared according to the following process. Step 1) A polymer electrolyte mixture containing a solution of polyethylene oxide (PEO, 100,000 g / mol, Alfa Aesar) in 99.7 wt% anhydrous anisole (Sigma-Aldrich) and lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI, over 98.0%, TCI) in acetonitrile is prepared. The weight ratio of PEO:LiTFSI in the mixture is 74:26. Step 1) The polymer electrolyte mixture prepared in Step 1), the positive electrode active material, and the conductive material powder (Super P, Timcal) are mixed in an acetonitrile solution at a weight ratio of 21:75:4 to prepare a slurry mixture. The mixing is carried out at 5000 rpm for 45 minutes using a homogenizer. Step 2) The slurry mixture from Step 2) is cast onto one side of an aluminum foil with a thickness of 20 μm with a coater gap of 100 μm. Step 3) The foil cast with the slurry is dried at 30 °C for 12 hours and then punched out to obtain a cathode liquid electrode with a diameter of 14 mm.

[0067] E1-3) Preparation of the negative electrode A Li foil (diameter 16 mm, thickness 500 μm) is prepared as the negative electrode.

[0068] E1-3) Assembly of the polymer cell The coin-type polymer cell is assembled from bottom to top in a glove box filled with argon in the order of a 2032 coin cell can, the positive electrode prepared in Section E1-2), the SPE prepared in Section E1-1), a gasket, the negative electrode prepared in Section E1-3), a spacer, a wave spring, and a cell cap. Then, the coin cell is completely sealed to prevent electrolyte leakage.

[0069] E2) Test method Each coin-type polymer cell is cycled at 80 °C using a Toscat-3100 computer-controlled constant current cycling station (manufactured by Toyo System). In the test procedure for the coin cell, a current definition of 1C at 160 mA / g is used in the voltage window range of 4.4~3.0V / Li metal according to the following schedule. Step 1) Charge at a constant current mode at a C rate of 0.05 until the end condition of 4.4V, and then rest for 10 minutes. Step 2) Discharge at a constant current mode at a C rate of 0.05 until the end condition of 3.0V, and then rest for 10 minutes. Step 3) Charge at a constant current mode at a C rate of 0.05 until the end condition of 4.4V. Step 4) Switch to the constant voltage mode and maintain 4.4 V for 60 hours. Step 5) At the end condition of 3.0 V, discharge in the constant current mode at a C rate of 0.05.

[0070] Q total is defined as the total leakage capacitance at high voltage and high temperature in Step 4) according to the described test method. Q total A small value of Q indicates high stability of the positive electrode active material powder during high-temperature operation.

[0071] Example 1 The polycrystalline positive electrode active material EX1 is prepared according to the following process. 1) Coprecipitation: A transition metal-based hydroxide oxide precursor having a metal composition of Ni 0.835 Mn 0.080 Co 0.085 is prepared by a coprecipitation process in a large continuous stirred tank reactor (CSTR) containing mixed manganese-cobalt sulfate, sodium hydroxide, and ammonia. 2) First mixing: The transition metal-based hydroxide oxide precursor and LiOH as a lithium source are homogeneously mixed at a lithium-to-metal M' (Li / M') ratio of 0.98 in an industrial blending device to obtain a first mixture. Here, M' is the total molar content of Ni, Mn, and Co. 3) First heating: The first mixture from Step 2) is heated at 770 °C for 10 hours in an oxygen atmosphere. The heated powder is pulverized, classified, and sieved to obtain a lithium transition metal composite oxide P1. 4) Second mixing: 60 grams of P1 is mixed with 0.12 grams of alumina (Al2O3) nano powder and 0.34 grams of WO3 to obtain a second mixture. 5) Second heating: The second mixture from Step 4) is heated at 350 °C for 6 hours in an oxygen atmosphere. The heated powder is labeled as EX1. The powder contains secondary particles composed of a plurality of primary particles.

[0072] Example 2 The single crystal positive electrode active material EX2 is prepared according to the following process. 1) Coprecipitation: A transition metal-based oxyhydroxide precursor having a metal composition of Ni 0.850 Mn 0.070 Co 0.080 is prepared by a coprecipitation process in a large continuous stirred tank reactor (CSTR) containing mixed manganese-cobalt sulfate, sodium hydroxide, and ammonia. 2) First mixing: The transition metal-based oxyhydroxide precursor and LiOH as a lithium source are homogeneously mixed in an industrial blending device at a lithium-to-metal M' (Li / M') ratio of 0.99 to obtain a first mixture. Here, M' is the total molar content of Ni, Mn, and Co. 3) First heating: The first mixture from step 2) is heated at 890 °C for 11 hours in an oxygen atmosphere. The heated powder is pulverized and sieved to obtain a lithium transition metal composite oxide P2a. 4) Wet pulverization: While pulverizing P2a in water, 0.50 mol% of CoSO4 is added based on the total amount of Ni, Mn, and Co in P2a. After filtering the solution, the slurry is dried at 175 °C for 15 hours in a dry air atmosphere to obtain P2b. 5) Second mixing: P2b is homogeneously mixed with ZrO2, Co3O4, and LiOH in an industrial mixing device to obtain a second mixture. Here, the amounts of ZrO2 and Co3O4 are 0.25 mol% and 0.50 mol% respectively based on the total amount of Ni, Mn, and Co in P2b, and the lithium-to-metal M' (Li / M') molar ratio of the second mixture is 0.99, where M' is the total molar content of Ni, Mn, and Co in the second mixture. 6) Second heating: The second mixture from step 5) is heated at 760 °C for 12 hours and 30 minutes in an oxygen atmosphere. The heated powder is pulverized and sieved to obtain a lithium transition metal composite oxide P2c. 7) Third mixing: 60 grams of P2c is mixed with 0.12 grams of alumina (Al2O3) nanopowder and 0.34 grams of WO3 to obtain a third mixture. 8) Third heating: The third mixture from step 7) is heated at 350 °C for 6 hours in an oxygen atmosphere. The heated powder is labeled as EX2. The powder contains single crystal particles.

[0073] Example 3 60 grams of P1 from Example 1, which is polycrystalline, is mixed with 0.12 grams of alumina (Al2O3) nano powder, 0.34 grams of WO3, and 0.18 grams of PVDF to obtain a mixture. The mixture is heated at 350 °C for 6 hours in an oxygen atmosphere. The heated powder is labeled as EX3.

[0074] Example 4 60 grams of P2c from Example 2, which is single crystal, is mixed with 0.12 grams of alumina (Al2O3) nano powder, 0.34 grams of WO3, and 0.18 grams of PVDF to obtain a mixture. The mixture is heated at 350 °C for 6 hours in an oxygen atmosphere. The heated powder is labeled as EX4.

[0075] Comparative Example 1 60 grams of P1 from Example 1 is mixed with 0.12 grams of alumina (Al2O3) nano powder and 0.18 grams of PVDF to obtain a mixture. The mixture is heated at 375 °C for 7 hours in an oxygen atmosphere. The heated powder is labeled as CEX1.

[0076] Comparative Example 2 60 grams of P1 from Example 1 is mixed with 0.34 grams of WO3 to obtain a mixture. The mixture is heated at 375 °C for 7 hours in an oxygen atmosphere. The heated powder is labeled as CEX2.

[0077] Table 2 summarizes the chemical compositions of the products of various examples and comparative examples, measured by ICP for Ni, Mn, Co, Al, and W, and by IC for F. Since these products do not contain any other dopants, the compositions in Table 2 are equivalent to the parameters x, y, z, v, w, and f defined in the claims.

[0078]

Table 3

[0079] Table 3 summarizes the chemical compositions of the products of various examples and comparative examples as measured by XPC for Ni, Mn, Co, Al, W, and F. Since these products contain no other dopants, the compositions in Table 3 are equivalent to the parameters Ni B , Mn B , Co B , Al B , W B , and F B defined in the claims.

[0080]

Table 4

[0081] Table 4 summarizes the addition amounts of Al2O3, WO3, and PVDF, the molar fraction ratios analyzed by XPS and ICP, and the corresponding Q total for the examples and comparative examples. Examples 1, 2, 3, and 4 contain both Al and W, while Comparative Example 1 contains Al and F, and Comparative Example 2 contains only W. Example 1 of the cathode active material containing a polycrystalline form is observed by SEM as shown in FIG. 1. FIG. 2 is a representative SEM image of Example 2 of the single-crystal cathode active material.

[0082]

Table 5

[0083] In Table 4, the XPS analysis results of Al (Al B ), W (W B ), and F (F B ) are compared with the ICP analysis results of Al(v), W(w), and F(f). Al B , W B , and F BBeing greater than 0 indicates that in relation to XPS measurements where the signal is obtained from the topmost part of the sample, i.e., the first few nanometers (e.g., 1 nm to 10 nm) of the surface layer, the Al, W, and F are present on the surface of the positive electrode active material. On the other hand, v, w, and f obtained from ICP measurements are from the whole particle. Therefore, Al B / v, W B / w and F B The fact that the ratios of XPS to ICP such as / f are greater than 1 indicates that the elements Al, W, and F are mainly present on the surface of the positive electrode active material. Higher Al B / v, W B / w and F B / f values correspond to more Al, W, and F being present on the surface of the positive electrode active material. All Al B / v in all examples except Comparative Example 2 is greater than 50, and all W B / w in all examples except Comparative Example 1 is greater than 20, and all F B / f in Examples 3, 4, and Comparative Example 1 is greater than 10, thereby confirming the effectiveness of the Al, W, and / or F treatment according to the present invention. Representative XPS spectra showing the Al2p, W4f5, and W4f7 peaks of Example 1 compared to Comparative Example 1 or Comparative Example 2 are shown in FIG. 3.

[0084] In some cases, the use of one or more dopants, such as elements B, Ba, Ca, Cr, Fe, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, or Zr, can be beneficial for battery characteristics. As is well known to those skilled in the art, such materials can be easily introduced by several methods, such as co-precipitation as in Step 1 of Examples 1 and 2, or addition of the necessary elemental sources in a mixing step with a Li source as in Step 2 of Examples 1 and 2, and many other methods known in the art.

Claims

1. A cathode active material for a solid-state battery, wherein the cathode active material contains Li, M', and oxygen, M' is, Ni with a content x of 50.0 mol% to 95.0 mol% with respect to M', Co with a content y of 0.0 mol% to 40.0 mol% with respect to M', Mn with a content z of 0.0 mol% to 70.0 mol% with respect to M', Al with a content v of 0.1 mol% to 3.0 mol%, W with a content w of 0.05 mol% to 2.0 mol%, F with a content f of less than 2.0 mol%, contains an element other than Li, O, Ni, Co, Mn, Al, W, and F with a content q of less than 3.0 mol% with respect to M', x, y, z, v, w, and q are measured by ICP, f is measured by IC, (x + y + z + v + w + f + q) = 100.0 mol%, The positive electrode active material is Al Ｂ / v > 25.0 and W Ｂ / w > 5.0, and has a ratio of Al Ｂ and W Ｂ are determined by XPS analysis, and Al Ｂ and W Ｂ are expressed as mol% compared with the total of Ni, Co, Mn, Al, W and F measured by XPS analysis, and are cathode active materials.

2. The ratio Al Ｂ / v is greater than 50.0, or greater than 60.0, or greater than 70.0, and the positive electrode active material according to claim 1.

3. The cathode active material according to claim 1, wherein the content z of Mn is 0.0 mol% to 40.0 mol% with respect to M'.

4. The ratio Al Ｂ / v is less than 250.0 or less than 200.0, and the positive electrode active material according to claim 1.

5. The ratio W Ｂ / w is greater than 10.0, or greater than 21.0, or greater than 22.0, the positive electrode active material according to claim 1.

6. The ratio W Ｂ / w is less than 150.0 or less than 100.

0. The positive electrode active material according to claim 1.

7. f > 0, and the positive electrode active material has a ratio F Ｂ / f > 10.0, where F Ｂ is determined by XPS analysis, and F Ｂ is expressed as mol% compared to the total of Ni, Co, Mn, Al, W, and F measured by XPS analysis. The positive electrode active material according to claim 1

8. The cathode active material according to claim 1, wherein the cathode active material contains secondary particles including two or more primary particles.

9. The cathode active material according to claim 1, wherein the cathode active material contains single crystal particles.

10. A cathode for a rechargeable lithium-ion battery, comprising the cathode active material according to any one of claims 1 to 9.

11. A polymer cell for a rechargeable lithium-ion battery, comprising the cathode active material according to any one of claims 1 to 9.

12. A rechargeable lithium-ion battery, comprising the cathode active material according to any one of claims 1 to 9.

13. A method for manufacturing a cathode active material for a solid-state battery, comprising: a step of preparing a lithium transition metal-based oxide compound; a step of mixing the lithium transition metal-based oxide compound with an Al source and a W source to obtain a mixture; a step of heating the mixture in an oxidizing atmosphere in a furnace at a temperature of 250°C to less than 500°C, or 250°C or higher and at most 450°C for a time of 1 hour to 20 hours to obtain the cathode active material powder, the method comprising these consecutive steps.

14. The method according to claim 13, wherein the lithium transition metal-based oxide compound is mixed with an additional F source to obtain the mixture.

15. The method according to claim 13 or 14, wherein the cathode active material is the cathode active material according to any one of claims 1 to 9.

16. A method for manufacturing a polymer cell for a rechargeable solid lithium-ion battery, the method comprising: Preparing a solid polymer electrolyte membrane by mixing a first polyethylene oxide having a molecular weight of less than 1,500,000 g / mol and greater than 500,000 g / mol and a lithium salt in a non-aqueous solvent; Preparing a positive electrode by mixing a second polyethylene oxide, a lithium salt, a positive electrode active material according to any one of claims 1 to 9, and a conductive material powder in a non-aqueous solvent, wherein the second polyethylene oxide has a molecular weight of less than 300,000 g / mol and greater than 50,000 g / mol; Preparing a negative electrode containing lithium metal; Assembling the solid polymer electrolyte membrane, the positive electrode, and the negative electrode to form a polymer cell for a rechargeable solid battery.

17. The method according to claim 16, wherein the positive electrode active material is the positive electrode active material according to any one of claims 1 to 9.

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