Lithium nickel-based complex oxides as positive electrode active materials for rechargeable lithium-ion batteries

Abstract

This invention provides a positive electrode active material powder for lithium-ion rechargeable batteries, wherein the positive electrode active material comprises Li, M', S, and O, wherein M' is composed of: - Ni with a content x between 60.0 mol% and 95.0 mol% relative to M', - Co with a content y between 0.0 mol% and 25.0 mol% relative to M', - Mn with a content z between 0.0 mol% and 25.0 mol% relative to M', and - Mn with a content a of 0.05 mol% or more relative to M'. W, - the content of b relative to M' is between 0.0 mol% and 2.0 mol% of D, wherein D includes at least one of the following elements: Al, B, Ba, Ca, Cr, F, Fe, Mg, Mo, Nb, Si, Sr, Ti, Y, V, Zn and Zr, and - wherein x, y, z, a and b are measured by ICP, - wherein x+y+z+a+b is 100.0 mol%, wherein the positive electrode active material contains soluble sulfur at a content of 0.30 mol% or more relative to M'.

Description

[0001] Technical Field and Background Technology

[0002] This invention relates to a lithium nickel-based oxide positive electrode active material for lithium-ion secondary batteries (LIBs) suitable for electric vehicle (EV) and hybrid electric vehicle (HEV) applications. The positive electrode active material powder comprises lithium transition metal-based oxide particles, which also contain sulfate ions (SO4). 2- ) soluble sulfur.

[0003] Positive electrode active materials are defined as materials that are electrochemically active in a positive electrode. For active materials, it is essential to understand their ability to capture and release lithium ions when subjected to voltage changes over a predetermined time period.

[0004] Specifically, the present invention relates to a high-nickel-based oxide positive electrode active material (hereinafter referred to as "high-Ni compound"), namely a high-Ni compound wherein the atomic ratio of Ni to M' is at least 75.0% (or 75.0 at%), preferably at least 77.5% (or 77.5 at%), and more preferably at least 80% (or 80.0 at%).

[0005] In the framework of this invention, at% represents atomic percentage. At% or "atomic percentage" in a given elemental expression of concentration refers to what percentage of all atoms in the claimed compound are atoms of the element.

[0006] The weight percentage (wt%) of the first element E in the material (E) wt1 The first element E in the material can be determined by applying the following formula: given atomic percentage (at%) (E) at1 Conversion: Where E at1 With E aw1 (E aw1 It is the product of the atomic weight (or molecular weight) of the first element E and the atomic weights (or molecular weights) of the other elements in the material. ati x E awi The sum, where n is an integer representing the number of different elements contained in the material.

[0007] With the development of EVs and HEVs, there is a demand for lithium-ion batteries that meet the requirements of such applications. There is an increasing exploration of high-Ni compounds as solid candidates for use as positive electrode active materials for LIBs because they are relatively inexpensive (compared to alternatives such as lithium cobalt-based oxides) and have high capacity at higher operating voltages.

[0008] For example, such high-Ni compounds are known from the literature JP5584456B2 (hereinafter referred to as "JP'456") or JP5251401B2 (hereinafter referred to as "JP'401").

[0009] JP'456 discloses a high-Ni compound having SO4 at the top of its particles in an amount ranging from 1000 ppm to 4000 ppm. 2- Ions (e.g., sulfate ions as described in JP'456). The calculated molar content of soluble sulfur relative to the total molar content of Ni, Co, and Mn is in the range of 0.1 mol% to 0.4 mol%. JP'456 explains that when the amount of sulfate ions is within the above range, the capacity retention and discharge capacity characteristics of the compound increase. However, if the amount of sulfate ions is less than the above range, the capacity retention decreases, and if the amount exceeds the above range, the discharge capacity decreases.

[0010] JP'401 proposes that applying a sulfate coating (particularly a lithium sulfate coating) to primary particles allows for the design of secondary particles generated from the aggregation of the sulfate-coated primary particles, possessing a specific pore structure to allow for the imparting of higher cycle durability and higher initial discharge capacity to high-Ni compounds made from the secondary particles. Furthermore, JP'401 states that this specific pore structure is achieved once the sulfate coating is washed away and removed.

[0011] Despite the promise of the aforementioned advantages, high-Ni compounds also have drawbacks, such as reduced cycle stability due to their high Ni content.

[0012] As an example of these drawbacks, existing high-Ni compounds have a low initial discharge capacity of no more than 180 mAh / g (JP'456) or a limited capacity retention of up to 86% (JP'401).

[0013] Currently, there is a need to achieve a high-Ni compound with a sufficiently high first discharge capacity (i.e., at least 207 mAh / g), which, according to the present invention, is a prerequisite for the use of such a high-Ni compound in LIBs suitable for (H)EV applications.

[0014] One object of the present invention is to provide a positive electrode active material having an improved initial charge capacity of at least 207 mAh / g.

[0015] Acknowledgments

[0016] This invention was completed with the support of the Materials / Components Technology Development Program of the Korea Assessment Industrial Technology Research Institute, funded by the Ministry of Trade, Industry and Energy (MOTIE, Republic of Korea). [Project Title: Development of High-Power (High-Discharge-Rate) Lithium-Ion Secondary Batteries with 8C Rate Rating / Project No.: 20011287 / Contribution Rate: 100%] Summary of the Invention

[0017] This objective is achieved by providing a positive electrode active material for lithium-ion batteries, wherein the positive electrode active material comprises Li, M', S, and O, wherein M' is composed of the following:

[0018] -Ni, the content x relative to M' is between 60.0 mol% and 95.0 mol%,

[0019] -Co, the content of which is y relative to M' is between 0.0 mol% and 25.0 mol%.

[0020] -Mn, the content of which z is between 0.0 mol% and 25.0 mol% relative to M',

[0021] -W, the content of which is between 0.05 mol% and 0.50 mol% relative to M'.

[0022] -D, the content of which b is between 0.0 mol% and 2.0 mol% relative to M', wherein D includes at least one of the following elements: Al, B, Ba, Ca, Cr, F, Fe, Mg, Mo, Nb, Si, Sr, Ti, Y, V, Zn, and Zr, and

[0023] -where x, y, z, a, and b are measured via ICP.

[0024] -where x+y+z+a+b is 100.0 mol%.

[0025] The positive electrode active material contains soluble sulfur in a content between 0.30 mol% and 2.00 mol% relative to M'.

[0026] Note that when an element is stated to exist in amounts between 0.0 mol% and another value, this means that the element may not be present at all; in other words, the element is optional.

[0027] Preferably, the soluble sulfur can associate with SO4. 2- Or in sulfate form, more precisely, in sulfate form such as Li₂SO₄, as determined by XPS. Soluble sulfur can also associate with SO₃. 2-Or in sulfite form, more precisely, sulfite.

[0028] According to stage A) ICP analysis in the detailed description, after washing the positive electrode active material of the present invention with water, the soluble sulfur content can be easily determined by ICP analysis.

[0029] In the framework of this invention, ppm refers to a concentration unit, parts per million, meaning 1 ppm = 0.0001 wt%.

[0030] Furthermore, within the framework of this invention, the term "sulfur" refers to the presence of sulfur atoms or sulfur elements in the claimed positive electrode active material.

[0031] This invention relates to the following embodiments:

[0032] Implementation Plan 1

[0033] In a first aspect, the present invention relates to a positive electrode active material for a lithium-ion battery, wherein the positive electrode active material comprises Li, M', S and O, wherein M' is composed of the following:

[0034] -Ni, the content x relative to M' is between 60.0 mol% and 95.0 mol%,

[0035] -Co, the content of which is y relative to M' is between 0.0 mol% and 25.0 mol%.

[0036] -Mn, the content of which z is between 0.0 mol% and 25.0 mol% relative to M',

[0037] -W, the content of which is 0.05 mol% or more relative to M'.

[0038] -D, the content of which b is between 0.0 mol% and 2.0 mol% relative to M', wherein D includes at least one of the following elements: Al, B, Ba, Ca, Cr, F, Fe, Mg, Mo, Nb, Si, Sr, Ti, Y, V, Zn, and Zr, and

[0039] -where x, y, z, a, and b are measured via ICP.

[0040] -where x+y+z+a+b is 100.0 mol%.

[0041] The positive electrode active material contains soluble sulfur at a content of 0.30 mol% or more relative to M'.

[0042] Preferably, the positive electrode active material contains soluble sulfur in an amount between 0.30 mol% and 2.00 mol% relative to the M' content.

[0043] Preferably, soluble sulfur is present in the positive electrode material at an amount between 0.50 mol% and 1.50 mol% relative to M'. More preferably, it is between 0.50 mol% and 1.00 mol% relative to M'.

[0044] Preferably, the soluble sulfur content is equal to the reduction of the S content relative to M' as determined by ICP after the following processes: contacting the positive electrode active material powder with deionized water several times (or dispersing it in deionized water) at 25°C for at least 5 minutes (by stirring), filtering the positive electrode active material powder, and drying the positive electrode active material powder.

[0045] In a preferred embodiment, the Ni is present in an amount of 75 mol% or more, and preferably at least 80 mol%.

[0046] In a preferred embodiment, the Ni is present at a content of 90 mol% or less.

[0047] In a preferred embodiment, the Co is present at a content of 5.0 mol% or more.

[0048] In a preferred embodiment, the Co is present in an amount of 10.0 mol% or less.

[0049] In a preferred embodiment, the Ni is present in an amount of 75 mol% or more, and preferably at least 80 mol%.

[0050] Preferably, a is at most 0.50 mol%.

[0051] In a preferred embodiment, the content of W a is between 0.05 mol% and 0.50 mol% relative to M'.

[0052] In another embodiment, the content of W, a, is between 0.10 mol% and 0.30 mol% relative to M'.

[0053] Implementation Plan 2

[0054] In a second embodiment, preferably according to embodiment 1, the positive electrode active material comprises Al with a content between 0.10 mol% and 1.00 mol% relative to M'.

[0055] Preferably, the positive electrode active material contains an Al content between 0.20 mol% and 0.50 mol% relative to M'.

[0056] Preferably, the positive electrode active material contains Al at a content of 0.10 mol% or more relative to M', and more preferably 0.20 mol% or more.

[0057] Preferably, the positive electrode active material comprises Al at a content of up to 1.0 mol% relative to M', and more preferably up to 0.50 mol%.

[0058] For completeness, it is emphasized that Al is included in D, such that the Al content is included in the parameter b.

[0059] Therefore, in other words, in a preferred embodiment, D comprises Al at a content of up to 1.0 mol% relative to M', and preferably up to 0.50 mol%.

[0060] In addition, in a preferred embodiment, D comprises Al at a content of 0.10 mol% or more relative to M', and preferably 0.20 mol% or more.

[0061] Implementation Plan 3

[0062] In a third embodiment, preferably according to embodiments 1 to 2, the positive electrode active material comprises B in a concentration between 0.05 mol% and 1.50 mol% relative to M'.

[0063] Preferably, the positive electrode active material contains a B content of at least 0.05 mol% relative to the M' content, and more preferably at least 0.1 mol%.

[0064] Preferably, the positive electrode active material contains B at a content of up to 1.5 mol% relative to M', and more preferably up to 1.0 mol%.

[0065] For completeness, it is emphasized that B is included in D, such that the content of B is included in the parameter b.

[0066] Therefore, in other words, in a preferred embodiment, D comprises B at a content of up to 1.5 mol%, more preferably 1.0 mol%, and even more preferably up to 0.50 mol%, relative to M'.

[0067] In addition, in a preferred embodiment, D comprises B in an amount of 0.05 mol% or more relative to M', and preferably 0.10 mol% or more.

[0068] Implementation Plan 4

[0069] In the third embodiment, preferably according to embodiments 1 to 3, the material has:

[0070] -S content S A and W content W A S A and W AThe S content was determined by ICP analysis. A and W A Expressed as a mole fraction compared to the sum of x, y, and z.

[0071] -Average S-score B and average W score W B S B and W B S was determined by XPS analysis. B and W B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis.

[0072] -where the ratio S B / S A >1.0,

[0073] -where the ratio W B / W A >1.0.

[0074] Preferably, the ratio S B / S A The ratio W is at least 1.5 and at most 600, and more preferably, the ratio W B / W A It is at least 1.5 and at most 700.

[0075] Preferably, the ratio S B / S A For at least 50 and at most 550, and more preferably S B / S A The number is at least 100 and at most 500.

[0076] Preferably, the ratio W B / W A For at least 50 and at most 700, and more preferably W B / W A The value is at least 100 and at most 650.

[0077] Note that S B and S A It refers to the total sulfur content, therefore including the content of soluble sulfur.

[0078] Implementation Plan 5

[0079] In the fifth embodiment, preferably according to embodiments 1 to 4, the material has:

[0080] -Al content Al A Al A Al was determined by ICP analysis. AExpressed as a mole fraction compared to the sum of x, y, and z.

[0081] -Average Al score Al B Al B The Al content was determined by XPS analysis. B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis.

[0082] -where the ratio Al B / Al A >1.0.

[0083] Preferably, the ratio Al B / Al A The value must be at least 3.0 and at most 2500.

[0084] Preferably, the ratio Al B / Al A For a minimum of 200 and a maximum of 2400, and more preferably Al B / Al A The number is at least 300 and at most 2300.

[0085] Implementation Plan 6

[0086] In the sixth embodiment, preferably according to embodiments 1 to 5, the material has:

[0087] -B content B A B A B was determined by ICP analysis. A Expressed as a mole fraction compared to the sum of x, y, and z.

[0088] -Average B score B B B B B was determined by XPS analysis. B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis.

[0089] -where the ratio B B / B A >1.0.

[0090] Preferably, ratio B B / B A The number is at least 100 and at most 1500.

[0091] Preferably, ratio B B / B A For a minimum of 200 and a maximum of 1400, and more preferably B B / B AThe limit is at least 300 and at most 1200.

[0092] Specifically, for any one of implementation schemes 1 to 6, S B W B Al B and B B These are the average fractions of S, W, Al, and B, measured in a region of the particles of the positive electrode material powder according to the invention. This region is defined between a first point at the outer edge of the particles and a second point at a distance from the first point, the distance separating the first and second points being equal to the penetration depth of the XPS, the penetration depth D being included between 1.0 and 10.0 nm. Specifically, the penetration depth is a distance along an axis perpendicular to a virtual line tangent to the outer edge and passing through the first point.

[0093] In the framework of this invention, the outer edge of a particle is the boundary or external limit that distinguishes the particle from its external environment.

[0094] The present invention relates to the use of the positive electrode active material according to any one of the foregoing embodiments 1 to 6 in a battery.

[0095] The present invention also includes a method for manufacturing a positive electrode active material according to any one of embodiments 1 to 6, the method comprising the following steps:

[0096] -Preparation of the first sintered lithium transition metal-based oxide compound

[0097] - The first sintered lithium transition metal-based oxide compound is mixed with a tungsten source, preferably WO3, a sulfate ion source, preferably Al2(SO4)3 and / or H2SO4, and water to obtain a mixture.

[0098] The mixture is heated in an oxidizing atmosphere in a furnace at a temperature of 350°C to less than 500°C, preferably up to 450°C, for 1 hour to 20 hours to obtain the positive electrode active material powder according to the invention.

[0099] Preferably, the lithium metal-based oxide compound is mixed with a boron source, preferably H3BO3, as well as a tungsten source and a sulfate ion source. Attached Figure Description

[0100] Figure 1 SEM images of .EX1.3

[0101] Figure 2a XPS spectra of Al 2p and Ni 3p peaks in EX1.4

[0102] Figure 2bXPS spectrum of the S2p peak of EX1.4

[0103] Figure 2c XPS spectrum of the W2f peak of EX1.4

[0104] Figure 2d XPS spectrum of the BLS peak of .EX3 Detailed Implementation

[0105] Preferred embodiments have been described in detail in the accompanying drawings and the following detailed description to enable 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. The invention includes many alternatives, modifications, and equivalents, which will become apparent from the following detailed description and drawings.

[0106] A) ICP analysis

[0107] Al)ICP measurement

[0108] The Li, Ni, Mn, Co, Al, B, W, and S contents of the positive electrode active material powder were measured using inductively coupled plasma (ICP) with an Agilent ICP720-ES. 2 g of the product powder sample was dissolved in 10 mL of high-purity hydrochloric acid in an Erlenmeyer flask. The flask was covered with a glass slide and heated on a hot plate at 380 °C until the precursor was completely dissolved. After cooling to room temperature, the solution from the Erlenmeyer flask was poured into a 250 mL volumetric flask. The volumetric flask was then filled with deionized water to the 250 mL mark and homogenized completely. A suitable amount of solution was taken out by pipette and transferred to a 250 mL volumetric flask for a second dilution, at which point the volumetric flask was filled with internal standard and 10% hydrochloric acid to the 250 mL mark and homogenized. Finally, this 50 mL solution was used for ICP measurement.

[0109] A2) Measurement of soluble sulfur

[0110] To investigate the soluble sulfur content in the lithium transition metal-based oxide particles according to the present invention, a washing and filtration process was performed. 5 g of positive electrode active material powder and 100 g of ultrapure water were weighed into a beaker. Using a magnetic stirrer, the electrode active material powder was dispersed in the water for 5 minutes at 25°C. The dispersion was vacuum filtered, and the dried powder was analyzed by the aforementioned ICP measurement to determine the amount of compounds containing soluble sulfur.

[0111] B) X-ray photoelectron spectroscopy analysis

[0112] In this invention, X-ray photoelectron spectroscopy (XPS) is used to analyze the surface of the positive electrode active material powder particles. In XPS measurements, signals are acquired from the first few nanometers (e.g., 1 nm to 10 nm) of the uppermost portion of the sample (i.e., the surface layer). Therefore, all elements measured by XPS are contained within the surface layer.

[0113] For surface analysis of the positive electrode active material powder particles, XPS measurements were performed using a Thermo K-α+ spectrometer (ThermoScientific, https: / / www.thermofisher.com / order / catalog / product / IQLAADGAAFFACVMAHV).

[0114] Monochromatic Al Ko radiation (hu = 1486.6 eV) was used with a spot size of 400 μm and a measurement angle of 45°. Wide-range measurement scans were performed at a pass energy of 200 eV to identify elements present on the surface. The CIs peak with maximum intensity (or intermediate intensity) at a binding energy of 284.8 eV was used as the calibration peak position after data collection. Subsequently, at least 10 precise narrow-range scans were performed at 50 eV for each identified element to determine the accurate surface composition.

[0115] Curve fitting was performed using CasaXPS version 2.3.19PR1.0 (Casa Software, http: / / www.casaxps.com / ) with Shirley-type background processing and Scofield sensitivity factor. The fitting parameters conform to Table 1a. The line shape GL(30) is the Gaussian / Lorentz product formula with a 70% Gaussian line and a 30% Lorentz line. LA(α,β,m) is an asymmetric line shape, where α and β define the tail extension of the peak, and m defines the width.

[0116] Table 1a. XPS fitting parameters for Ni2p3, Mn2p3, Co2p3, Al2p, S2p, W4f and B1s .

[0117]

[0118] For the Al, S, Co, and W peaks, constraints are set for each defined peak according to Table 1b. Unquantized Ni3p (including Ni3p3, Ni3pl, Ni3p3 satellite, and Ni3pl satellite) and W5p3 are also included.

[0119] Table 1b. XPS fitting constraints for peak fitting .

[0120]

[0121] The surface contents of Al, S, B, and W determined by XPS are expressed as the mole fractions of Al, S, B, and W in the particle surface layer divided by the total contents of Ni, Mn, and Co in the surface layer.

[0122] The calculation is as follows:

[0123] The fraction of Al = Al B =Al (atomic %) / (Ni (atomic %) + Mn (atomic %) + Co (atomic %))

[0124] The fraction of S = S B = S (atomic %) / (Ni (atomic %) + Mn (atomic %) + Co (atomic %))

[0125] W's fraction = W B =W(atomic%) / (Ni(atomic%)+Mn(atomic%)+Co(atomic%))

[0126] B's fraction = B B = B (atomic %) / (Ni (atomic %) + Mn (atomic %) + Co (atomic %))

[0127] Information on XPS peak positions can be easily obtained from the fitted region and component report specifications. XPS curves for Al, S, W, and B are shown below. Figure 2a , 2b In 2c and 2d.

[0128] C) Button battery testing

[0129] C1) Button cell manufacturing

[0130] To prepare the positive electrode, a slurry containing positive electrode active material powder, a conductor (Super P, Timcal), and a binder (KF#9305, Kureha) (in a weight ratio of 96.5:1.5:2.0) was prepared in a solvent (NMP, Mitsubishi) using a high-speed homogenizer. The homogenized slurry was applied to one side of an aluminum foil using a doctor blade coater with a 170 μm gap. The slurry-coated foil was dried in an oven at 120°C and then pressed using a calendering tool. It was then dried again in a vacuum oven to completely remove any remaining solvent from the electrode film. The coin cell was assembled in an argon-filled glove box. A separator (Celgard 2320) was positioned between the positive electrode and the lithium foil sheet used as the negative electrode. EC / DMC (1:2) containing 1M LiPF6 was used as the electrolyte and dropped between the separator and the electrode. The coin cell was then completely sealed to prevent electrolyte leakage.

[0131] C2) Test Method

[0132] The testing method is the conventional "constant cutoff voltage" test. The conventional button cell battery test in this invention follows the plan shown in Table 2. Each battery was cycled at 25°C using a Toscat-3100 computer-controlled constant current cycling station (from Toyo). A 1C current definition of 220 mA / g was used. Initial charge capacity (CQ1) and discharge capacity (DQ1) were measured at a C-rate of 0.1C within a metal window range of 4.3V to 3.0V / Li in constant current mode (CC).

[0133] The irreversible capacity IRRQ is expressed as a percentage as follows:

[0134]

[0135] Table 2. Cyclic Plan for Button Battery Testing Methods

[0136]

[0137] The present invention is further illustrated by the following embodiments:

[0138] Comparative Example 1

[0139] Li was obtained through a double sintering process. 1+d (Ni 0.80 Mn 0.10 Co 0.10 ) i-d The high-Ni compound CEX1 with O2, and the dual sintering process, which is a solid-state reaction between a lithium source and a transition metal-based source, operates as follows:

[0140] 1) Coprecipitation: A coprecipitation process is used to prepare a metal with a Ni composition in a large continuous stirred tank reactor (CSTR) containing a mixture of nickel, manganese, and cobalt sulfate, sodium hydroxide, and ammonia. 0.80 Mn 0.10 Co 0.10 .io transition metal-based oxidized hydroxide precursors.

[0141] 2) Blending: The transition metal-based hydroxide and LiOH as the lithium source are uniformly blended in an industrial blending device at a lithium to metal M' (Li / M') ratio of 1.01.

[0142] 3) First sintering: The blend is sintered at 730°C for 12 hours in an oxygen-containing atmosphere. The sintered powder is crushed, sorted, and sieved to obtain sintering intermediate products.

[0143] 4) Second sintering: The intermediate product is sintered at 830°C for 12 hours in an oxygen-containing atmosphere to obtain sintered powder of aggregated primary particles. The sintered powder is crushed, sorted, and sieved to obtain the product with the formula Li.1.005 M' 0.995 O2 (d = 0.005) CEX1, where M' = Ni 0.80 Mn 0.10 Co 0.10 CEX1 has a D50 of 12.0 μm and a span of 1.24. CEX1 contains trace amounts of sulfur obtained from the metal sulfate source in the coprecipitation process of step 1).

[0144] Optionally, the dopant source may be added together with the lithium source in the co-precipitation process of step 1) or in the blending step of step 2). For example, dopants may be added to improve the electrochemical properties of the positive electrode active material powder product.

[0145] CEX1.1 is not based on the present invention.

[0146] The CEX1.2 not according to the present invention is prepared by the following procedure:

[0147] Step 1) Wet mixing: CEX1.1 is mixed with an aluminum sulfate solution prepared by dissolving 1000 ppm of Al obtained from Al2(SO4)3 powder in 3.5% by weight of deionized water relative to the weight of CEX1.1.

[0148] Step 2) Heating: The mixture obtained from Step 1) is heated at 385°C for 8 hours in an oxygen atmosphere, then ground and sieved to obtain CEX1.2 containing approximately 1000 ppm Al relative to the total weight of EX1.2.

[0149] Example 1

[0150] According to the present invention, EX1.1 is prepared by the following procedure: Step 1) Dry mixing: CEX1.1 is dry mixed with 2000 ppm of W obtained from WO3 powder to obtain a dry mixture.

[0151] Step 2) Wet mixing: The dry mixture obtained from Step 1) is mixed with an aluminum sulfate solution to obtain a wet mixture, the aluminum sulfate solution being prepared by dissolving 600 ppm of Al obtained from Al2(SO4)3 powder in 3.5% by weight of deionized water relative to CEX1.1.

[0152] Step 3) Heating: The wet mixture obtained in step 2) is heated at 385°C for 8 hours in an oxygen atmosphere, then ground and sieved to obtain EX1.2.

[0153] EX1.2 according to the present invention is prepared according to the same method as EX1.1, except that 3000 ppm W is added in step 1).

[0154] EX1.3 according to the present invention was prepared using the same method as EX1.1, except that 4000 ppm W was added in step 1). SEM images of EX1.3 were taken, see... Figure 1 .

[0155] EX1.4 according to the present invention is prepared according to the same method as EX1.1, except that 800 ppm Al is added in step 2).

[0156] EX1.5 according to the invention is prepared according to the same method as EX1.4, except that 3000 ppm W is added in step 1).

[0157] EX1.6 according to the invention is prepared according to the same method as EX1.4, except that 4000 ppm W is added in step 1).

[0158] Example 2

[0159] EX2 according to the present invention is prepared by the following procedure: Step 1) Dry mixing: CEX1.1 is dry mixed with 4500 ppm of W obtained from WO3 powder to obtain a dry mixture.

[0160] Step 2) Wet Mixing: The dry mixture obtained from Step 1) is mixed with 0.5 mol% of S obtained from a sulfuric acid solution to obtain a wet mixture, wherein the sulfuric acid solution is prepared by dissolving a concentrated H2SO4 solution (98% concentration) in 3.5 wt% of deionized water relative to CEX1.1.

[0161] Step 3) Heating: The wet mixture obtained in step 2) is heated at 285°C for 8 hours in an oxygen atmosphere, then ground and sieved to obtain EX1.2.

[0162] Comparative Example 2

[0163] CEX2, which is not based on the invention, is prepared using the same method as EX2, except that the wet mixing step 2 is omitted.

[0164] Example 3

[0165] EX3 according to the present invention is prepared by the following procedure: Step 1) Dry mixing: CEX1.1 is dry mixed with 500 ppm of B obtained from H3BO3 and 4500 ppm of W obtained from WO3 powder to obtain a dry mixture.

[0166] Step 2) Wet mixing: The dry mixture obtained from Step 1) is mixed with an aluminum sulfate solution prepared by dissolving 1000 ppm of Al obtained from Al2(SO4)3 powder in 3.5% by weight of deionized water relative to the weight of the dry mixture.

[0167] Step 3) Heating: The wet mixture obtained in step 2) is heated at 385°C for 8 hours in an oxygen atmosphere, then ground and sieved to obtain EX3.

[0168] Table 3. Overview of the composition and corresponding electrochemical properties of the examples and comparative examples .

[0169]

[0170] *Molar content relative to Ni, Mn, Co, Al, and W

[0171] Table 4. XPS analysis results and ICP analysis rates for CEX1.2, EX1.4, and EX3

[0172]

[0173] **M: Molar content of a specific element relative to the molar content of Ni, Mn, and Co.

[0174] Table 5. XPS peak positions for CEX1.2, EX1.4, and EX3

[0175]

[0176] Table 3 summarizes the Al, W, and soluble S compositions and their corresponding electrochemical properties in the Examples and Comparative Examples. EX1.1 to EX1.6 and EX2, containing W at contents between 0.05 mol% and 0.50 mol% relative to M' and soluble S at contents between 0.30 mol% and 2.00 mol% relative to M', achieve the objective of the present invention, namely, providing a positive electrode active material with an improved initial charge capacity of at least 207 mAh / g. Furthermore, EX3 also contains 0.4 mol% B, which further improves the electrochemical properties.

[0177] Table 4 summarizes the XPS analysis results for CEX1.2, EX1.4, and EX3, showing the atomic ratios of Al, S, B, and W relative to the total atomic fractions of Ni, Mn, and Co. The table also compares the results with those from ICP. An atomic ratio greater than 0 indicates that the Al, S, B, and W, as associated with the XPS measurements, are present on the surface of the positive electrode active material, with the XPS signal obtained from the first few nanometers (e.g., 1 nm to 10 nm) of the topmost portion of the sample (i.e., the surface layer). On the other hand, the Al, S, B, and W atomic ratios obtained by ICP measurements are derived from the entire particle. Therefore, an XPS / ICP ratio greater than 1 indicates that the element Al, S, B, or W is predominantly present on the surface of the positive electrode active material. An XPS / ICP ratio greater than 1 was observed for Al, S, and W in EX1.4. Similarly, an XPS / ICP ratio greater than 1 was observed for Al, S, B, and W in EX3.

[0178] Table 5 shows the positions of the Al2p, S2p3, W4f7, and Bls XPS peaks of CEX1.2, EX1.4, and EX3 obtained by XPS analysis according to the present invention.

Claims

1. A positive electrode active material powder for lithium-ion rechargeable batteries, wherein the positive electrode active material powder comprises Li, S, M' and O, wherein M' is composed of the following elements: -Ni, the Ni content x relative to M' is between 60.0 mol% and 95.0 mol%. -Co, the content of Co relative to M' is between 0.0 mol% and 25.0 mol%. -Mn, the content of Mn z relative to M' is between 0.0 mol% and 25.0 mol%. -W, the content of W a relative to M' is 0.11 mol% or more and 0.30 mol% or less, -D, the content of D relative to M' is between 0.0 mol% and 2.0 mol%, wherein D includes at least one of the following elements: Al, B, Ba, Ca, Cr, F, Fe, Mg, Mo, Nb, Si, Sr, Ti, Y, V, Zn, and Zr, and -Where x, y, z, a, and b are measured via ICP. -where x+y+z+a+b is 100.0 mol%. The positive electrode active material powder contains soluble sulfur at a content of 0.30 mol% or more and 2.00 mol% or less relative to M'.

2. The positive electrode active material powder according to claim 1, wherein the content of soluble sulfur is equal to the reduction of the S content relative to M' as determined by ICP after the following processes: dispersing the positive electrode active material powder in deionized water to obtain a solution, stirring the solution at 25°C for at least 5 minutes, filtering the positive electrode active material powder, and drying the positive electrode active material powder.

3. The positive electrode active material powder according to claim 1 or 2, wherein x is between 75 mol% and 90 mol%.

4. The positive electrode active material powder according to claim 1 or 2, wherein the content of soluble sulfur is 0.50 mol% or more relative to M'.

5. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder contains Al in an amount of 0.10 mol% or more relative to M'.

6. The positive electrode active material powder according to claim 5, wherein the positive electrode active material powder comprises Al in an amount of 0.20 mol% or more relative to M'.

7. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder comprises Al in a content of up to 1.0 mol% relative to M'.

8. The positive electrode active material powder according to claim 7, wherein the positive electrode active material powder comprises Al in a content of up to 0.50 mol% relative to M'.

9. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder contains B in a content of at least 0.05 mol% relative to M'.

10. The positive electrode active material powder according to claim 9, wherein the positive electrode active material powder comprises B in a content of at least 0.1 mol% relative to M'.

11. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder contains B in a content of up to 1.5 mol% relative to M'.

12. The positive electrode active material powder according to claim 11, wherein the positive electrode active material powder contains B in a content of up to 1.0 mol% relative to M'.

13. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder has: -S content S A and W content W A S A and W A It was determined by ICP analysis, in which S A and W A Expressed as a mole fraction compared to the sum of x, y, and z. -Average S-score B and average W score W B S B and W B It was determined by XPS analysis, where S B and W B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis. -where the ratio S B / S A >1.0, -where the ratio W B / W A >1.

0.

14. The positive electrode active material powder according to claim 13, wherein the ratio S B / S A It should be at least 1.

5.

15. The positive electrode active material powder according to claim 13, wherein the ratio W B / W A It should be at least 1.

5.

16. The positive electrode active material powder according to claim 13, wherein the ratio S B / S A The maximum is 600.

17. The positive electrode active material powder according to claim 13, wherein the ratio W B / W A The maximum is 700.

18. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder comprises: -Al content Al A Al A It was determined by ICP analysis, in which Al A Expressed as a mole fraction compared to the sum of x, y, and z. -Average Al score Al B Al B It was determined by XPS analysis, in which Al B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis. -where the ratio Al B / Al A >1.

0.

19. The positive electrode active material powder according to claim 18, wherein the ratio of Al B / Al A It should be at least 3.

0.

20. The positive electrode active material powder according to claim 18, wherein the ratio of Al... B / Al A The maximum is 2400.

21. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder contains soluble sulfur in an amount of 1.00 mol% or less relative to M'.

22. The positive electrode active material powder according to claim 1 or 2, wherein y is between 5 mol% and 10 mol% relative to M'.

23. The positive electrode active material powder according to claim 1 or 2, wherein the positive electrode active material powder comprises: -B content B A B A It was determined by ICP analysis, in which B A Expressed as a mole fraction compared to the sum of x, y, and z. -Average B score B B B B It was determined by XPS analysis, where B B Expressed as the mole fraction compared to the sum of the fractions of Co, Mn, and Ni measured by XPS analysis. -where the ratio B B / B A >1.

0.

24. The positive electrode active material powder according to claim 23, wherein the ratio B B / B A The minimum is 100.

25. The positive electrode active material powder according to claim 23, wherein the ratio B B / B A The maximum is 1500.

26. A method for manufacturing a positive electrode active material powder according to any one of claims 1 to 25, the method comprising the following sequential steps: -Preparation of the first sintered lithium transition metal-based oxide compound - The first sintered lithium transition metal-based oxide compound is mixed with a tungsten source, a sulfate ion source, and water to obtain a mixture, and - The mixture is heated in an oxidizing atmosphere in a furnace at a temperature of 350°C to less than 500°C for 1 hour to 20 hours to obtain the positive electrode active material powder.

27. The method of claim 26, wherein the tungsten source is WO3.

28. The method of claim 26, wherein the sulfate ion source is Al2(SO4)3 and / or H2SO4.

29. The method of claim 26, wherein the temperature is at most 450°C.

30. The method of claim 26, wherein the lithium metal-based oxide compound is mixed with a boron source, a tungsten source, and a sulfate ion source.

31. The method of claim 30, wherein the boron source is H3BO3.

32. A battery comprising a positive electrode active material powder according to any one of claims 1 to 25.

33. Use of the battery according to claim 32 in an electric vehicle.

34. Use of the battery according to claim 32 in a hybrid electric vehicle.

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