Positive electrode active material for lithium-ion rechargeable batteries

Abstract

1. A cathode active material for a lithium ion liquid electrolyte rechargeable battery, the cathode active material being a powder comprising Li, M', and O, wherein M' is composed of: Co in a content x of 2.0 mol% or more and 35.0 mol% or less; Mn in a content y of 0 mol% or more and 35.0 mol% or less; A in a content m of 0 mol% or more and 5 mol% or less, the A containing at least one element selected from the group consisting of Al, Ba, B, Mg, Nb, Sr, Ti, W, S, Ca, Cr, Zn, V, Y, Si, and Zr; and Ni in a content of (100-xym) mol%, the powder being a single crystal powder. 2. A cathode active material comprising: a first compound containing LiWO; and a second compound containing WO; the powder being a single crystal powder; and the cathode active material containing Li in a molar ratio of Li / (Co+Mn+Ni+A) of at least 0.9 and at most 1.1.

Description

[Technical Field]

[0001] The present invention relates to a particulate active cathode material for lithium ionic liquid electrolyte rechargeable batteries. More specifically, the present invention relates to a particulate active cathode material comprising tungsten oxide. [Background technology]

[0002] The present invention relates to a single-crystalline positive electrode active material powder for lithium-ion rechargeable batteries (LIBs), comprising a first compound comprising lithium tungsten oxide and a second compound comprising tungsten oxide.

[0003] Such a positive electrode active material is already known, for example, from Korean Patent Publication No. 2019 / 0078991. Korean Patent Publication No. 2019 / 0078991 discloses a positive electrode active material powder containing a mixture of a lithium transition metal oxide and a lithium tungsten oxide compound. However, the positive electrode active material disclosed in Korean Patent Publication No. 2019 / 0078991 has a low initial discharge capacity (DQ1) and a high irreversible capacity (IRRQ). Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to provide positive electrode active materials having improved electrochemical properties, for example, as indicated by DQ1 and IRRQ values ​​in an electrochemical cell, as determined by the analytical methods of the present invention. [Means for solving the problem]

[0005] The object is to provide an active cathode material for a lithium-ion rechargeable battery, the active cathode material comprising Li, M', and O, wherein M' is: Co with a content x of 2.0 mol% or more and 35.0 mol% or less relative to M'; Mn having a content y of 0 mol% or more and 35.0 mol% or less relative to M'; A having a content m of 0 mol % or more and 5 mol % or less relative to M', which contains at least one element selected from the group consisting of Al, Ba, B, Mg, Nb, Sr, Ti, W, S, Ca, Cr, Zn, V, Y, Si, and Zr; (100-xym) mol% Ni content, i. a first compound comprising Li2WO4, and ii. A powder comprising a second compound comprising WO3; the powder is a single crystal powder, This is achieved by providing an active cathode material, wherein the active cathode material comprises Li in a molar ratio of Li / (Co+Mn+Ni+A) of at least 0.900 and at most 1.100.

[0006] As illustrated by the examples and supported by the results shown in Table 2, the realization of higher DQ1 and lower IRRQ is indeed observed using the cathode active material powder according to the present invention.

[0007] The present invention further provides an electrochemical cell comprising the active cathode material according to the first aspect of the invention, a lithium-ion rechargeable battery comprising a liquid electrolyte and the active cathode material according to the first aspect of the invention, and the use of the active cathode material according to the first aspect of the invention in a battery in any one of a portable computer, a tablet, a mobile phone, an electric vehicle, and an energy storage system.

[0008] For further guidance, figures are included to better understand the teachings of the present invention, which are intended to aid in the explanation of the invention and are not intended to limit the invention of this disclosure. [Brief explanation of the drawings]

[0009] [Figure 1] 1 shows an X-ray diffractogram of a positive electrode active material powder containing Li2WO4 and WO3 compounds according to EX1.7. [Figure 2] X-ray diffractograms of CEX2, EX1.4, and CEX3.3 are shown. DETAILED DESCRIPTION OF THE INVENTION

[0010] In these figures, the horizontal axis represents the diffraction angle 2θ in degrees, and the vertical axis represents the signal intensity on a logarithmic scale.

[0011] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which this invention belongs. By way of further guidance, definitions of terms are included to better understand the teachings of the present invention. As used herein, the following terms have the following meanings: As used herein, "about" referring to a measurable value such as a parameter, amount, duration, etc., is meant to encompass a variation of no more than ±20%, preferably no more than ±10%, more preferably no more than ±5%, even more preferably no more than ±1%, and still more preferably no more than ±0.1% from the specified value, provided that such variations are appropriate for the practice of the disclosed invention, provided that the value to which the "about" modifier refers is itself specifically disclosed.

[0012] The recitation of numerical ranges by endpoints includes not only the recited endpoints but also all numbers and fractions subsumed within that range. All percentages are to be understood as weight percentages, abbreviated as "wt. %," unless otherwise defined or unless a different meaning is apparent to one of ordinary skill in the art from their usage and the context in which they are used.

[0013] The term "ppm" as used herein means parts per million by mass.

[0014] positive electrode active material In a first aspect, the present invention provides a cathode active material, the cathode active material comprising Li, M′, and O, wherein M′ is: Co with a content x of 2.0 mol% or more and 35.0 mol% or less relative to M'; Mn having a content y of 0 mol% or more and 35.0 mol% or less relative to M'; A having a content m of 0 mol % or more and 5 mol % or less relative to M', which contains at least one element selected from the group consisting of Al, Ba, B, Mg, Nb, Sr, Ti, W, S, Ca, Cr, Zn, V, Y, Si, and Zr; Ni in an amount of (100-xym) mol% relative to M', and i. a first compound comprising Li2WO4, and ii. A powder comprising a second compound comprising WO3; the powder is a single crystal powder, An active cathode material is provided, wherein the active cathode material includes Li in a molar ratio of Li / (Co+Mn+Ni+A) of at least 0.900 and at most 1.100.

[0015] The single crystal powder has a size of at least 45 μm by at least 60 μm (i.e., at least 2700 μm) in the SEM image. 2 ), preferably at least 100 μm by at least 100 μm (i.e., at least 10,000 μm 2 ) is considered to be a powder in which 80% or more of the particles within the field of view have a single crystal morphology.

[0016] A particle is considered to have monocrystalline morphology if it consists of only one grain or a very small number of constituent grains, up to a maximum of five, as observed by SEM or TEM. Conversely, a particle is considered to have polycrystalline morphology if it consists of at least six constituent grains as observed by SEM or TEM.

[0017] In determining the single-crystal morphology of a particle, grains having a largest linear dimension observed by SEM that is smaller than 20% of the powder's median particle size D50 as determined by laser diffraction are ignored. This avoids inadvertently assuming that particles that are essentially single-crystal but have several other, much smaller grains deposited on them do not have single-crystal morphology.

[0018] The inventors have found that the active cathode material for lithium rechargeable batteries according to the present invention indeed provides higher DQ1 and lower IRRQ, as illustrated by the examples and the results shown in Table 2.

[0019] Preferably, the present invention provides a cathode active material according to a first aspect of the present invention, wherein the total tungsten content is at least 0.20 wt % and / or at most 2.50 wt %, based on the total weight of the cathode active material, as determined by ICP-OES analysis, where ICP-OES means inductively coupled plasma optical emission spectroscopy. Preferably, the weight ratio is between 0.25 wt % and 2.00 wt %, more preferably, the weight ratio is equal to 0.30, 0.50, 1.00, 1.50, 2.00, or any value therebetween.

[0020] Positive active material is defined as a material that is electrochemically active in the positive electrode, and is understood to be a material that can capture and release Li ions when exposed to a voltage change over a period of time.

[0021] The content of each element can be determined by a known analytical method such as ICP-OES (inductively coupled plasma-optical emission spectrometry).

[0022] The content of Ni in the positive electrode active material (100-xym) is preferably ≧60 mol %, more preferably ≧65 mol %, relative to M′.

[0023] The Ni content (100-xym) in the positive electrode active material is preferably ≦95 mol %, more preferably ≦90 mol %, relative to M′.

[0024] The content y of Mn in the positive electrode active material is preferably ≧0 mol %, more preferably ≧5 mol %, relative to M′.

[0025] The Mn content y in the positive electrode active material is preferably ≦35 mol %, more preferably ≦30 mol %, relative to M′.

[0026] The content x of Co in the positive electrode active material is preferably ≧2 mol %, more preferably ≧5 mol %, relative to M′.

[0027] The content x of Co in the positive electrode active material is preferably ≦35 mol %, more preferably ≦30 mol %, relative to M′.

[0028] The content m of A in the positive electrode active material is preferably 0.01 mol % or more relative to M'.

[0029] The content m of A in the positive electrode active material is preferably 2.0 mol % or less relative to M'.

[0030] Preferably, the positive electrode active material has a median particle size D50 of 2 μm to 7 μm, as determined by laser diffraction particle size distribution analysis.

[0031] The size D99 of the positive electrode active material is preferably at least 5 μm and at most 25 μm, more preferably at least 7 μm and at most 20 μm, as determined by laser diffraction particle size distribution analysis.

[0032] Herein, D50 and D99 are defined as the particle sizes at 50% and 99%, respectively, of the cumulative volume percent distribution of the positive electrode active material powder, which can be determined by laser diffraction particle size distribution analysis.

[0033] First Compound and Second Compound Preferably, the present invention provides a cathode active material according to the first aspect of the present invention, wherein the first compound comprises Li2WO4 and belongs to the space group R-3, and the second compound comprises WO3 and belongs to the space group P21 / n, as determined by X-ray diffraction analysis.

[0034] Preferably, the present invention provides a cathode active material according to the first aspect of the present invention, wherein the total tungsten content, as determined by ICP-OES analysis, is 0.20 wt % to 2.50 wt %, based on the total weight of the cathode active material. Preferably, the weight ratio is 0.25 wt % to 2.00 wt %, more preferably, the weight ratio is equal to 0.50, 1.00, 1.50, 2.00, or any value therebetween.

[0035] In a second aspect, the present invention provides a battery cell comprising an active cathode material according to the first aspect of the present invention.

[0036] In a third aspect, the present invention provides the use of the cathode active material according to the first aspect of the present invention in a battery of any one of a portable computer, a tablet, a mobile phone, an electric vehicle, and an energy storage system.

[0037] Third compounds of lithium transition metal oxides Preferably, the present invention provides an active cathode material according to the first aspect of the present invention, wherein the active cathode material comprises a third compound belonging to the R-3m space group as determined by X-ray diffraction analysis.

[0038] Preferably, the third compound is a lithium transition metal oxide, i.e., Li-M'-oxide as defined herein above. The lithium transition metal oxide is identified by X-ray diffraction analysis. According to "Journal of Power Sources (2000), 90, 76-81", the lithium transition metal oxide has a crystal structure belonging to the R-3m space group.

[0039] electrochemical cell In a second aspect, the present invention provides an electrochemical cell comprising an active cathode material according to the first aspect of the invention, a lithium-ion rechargeable battery comprising a liquid electrolyte and an active cathode material according to the first aspect of the invention, and the use of an active cathode material according to the first aspect of the invention in a battery in any one of a portable computer, a tablet, a mobile phone, an electric vehicle, and an energy storage system.

[0040] Method for preparing positive electrode active material Preferably, the present invention relates to a method for preparing a cathode active material according to the first aspect of the present invention as described herein above, the method comprising the steps of: mixing a powder of a single-crystal lithium transition metal oxide with a W-containing compound to obtain a mixture; and a step of heating the mixture in an oxidizing atmosphere at a temperature of 250°C to 450°C to obtain the positive electrode active material.

[0041] Preferably, the W-containing compound is WO3.

[0042] Preferably, the amount of W used in the process is 0.20 wt % to 2.50 wt % based on the total weight of the cathode active material, as determined by ICP-OES analysis.

[0043] The second mixture is heated at a temperature of preferably 300°C to 400°C, more preferably 325°C to 375°C.

[0044] Preferably, the heated powder and / or cathode material is further processed, for example by grinding and / or sieving.

[0045] Optionally, the lithium transition metal oxide comprises A, wherein A comprises at least one element selected from the group consisting of Al, Ba, B, Mg, Nb, Sr, Ti, W, S, Ca, Cr, Zn, V, Y, Si, and Zr. [Example]

[0046] The following examples are intended to further clarify the present invention, but are not intended to limit the scope of the invention.

[0047] 1. Explanation of analysis method 1.1.Inductively Coupled Plasma The composition of the positive electrode active material powder was measured by inductively coupled plasma (ICP) analysis using an Agilent 720 ICP-OES (Agilent Technologies, https: / / www.agilent.com / cs / library / brochures / 5990-6497EN%20720-725_ICP-OES_LR.pdf). One gram of powder sample was dissolved in 50 mL of high-purity hydrochloric acid (at least 37 wt% HCl based on the total weight of the solution) in an Erlenmeyer flask. The flask was covered with a watch glass and heated on a hot plate at 380 °C until the powder was completely dissolved. After cooling to room temperature, the solution from the Erlenmeyer flask was poured into a first 250 mL volumetric flask. The first volumetric flask was then filled to the 250 mL mark with deionized water, followed by a thorough homogenization process (first dilution). Pipette an appropriate amount of the solution from the first volumetric flask into a second 250 mL volumetric flask for the second dilution, fill the second volumetric flask to the 250 mL mark with the internal standard and 10% hydrochloric acid, and then homogenize. Finally, use this solution for ICP-OES measurement.

[0048] 1.2.Particle size distribution The particle size distribution (PSD) of the cathode active material powders was measured by laser diffraction particle size distribution analysis using a Malvern Mastersizer 3000 equipped with the Hydro MV wet dispersion accessory (https: / / www.malvernpananalytical.com / en / products / product-range / mastersizer-range / mastersizer-3000#overview) after dispersing each powder sample in an aqueous medium. Sufficient ultrasonic irradiation and stirring were applied to improve the powder dispersion, and appropriate surfactants were introduced. D50 and D99 are defined as the particle sizes at 50% and 99%, respectively, of the cumulative volume percent distribution obtained with the Malvern Mastersizer 3000 according to the Hydro MV values.

[0049] X-ray diffraction X-ray diffraction patterns of the positive electrode active material were collected using a Rigaku X-Ray Diffractometer D / max2000 (Rigaku, Du, Y. et al. (2012). A general method for the large-scale synthesis of uniform ultrathin metal sulfide nanocrystals. Nature Communications, 3(1)) with a CuKα source (40 kV, 40 mA) emitting at a wavelength of 1.5418 Å. The instrument configuration was set to a 1° Soller slit (SS), a 10 mm divergence height limiting slit (DHLS), a 1° divergence slit (DS), and a 0.3 mm receiving slit (RS). The goniometer diameter was 185 mm. For XRD, diffraction patterns were acquired in the range of 15–70° (2θ) at a scan rate of 1° per minute and a step size of 0.02° per scan.

[0050] 1.4. Coin Cell Test 1.4.1. Coin Cell Preparation To prepare the positive electrode, a slurry containing the positive electrode active material powder, conductive agent (Super P, Timcal), and binder (KF#9305, Kureha) in a solvent (NMP, Mitsubishi Chemical) in a weight ratio of 90:5:5 was prepared using a high-speed homogenizer. The homogenized slurry was spread onto one side of aluminum foil with a 230 μm gap using a doctor blade coater. The slurry-coated foil was dried in an oven at 120 °C and then pressed using a calendar tool. It was then dried again in a vacuum oven to completely remove residual solvent in the electrode film. Coin cells were assembled in an argon-filled glove box. A separator (Celgard 2320) was placed between the positive electrode and a piece of lithium foil used as the negative electrode. 1 M LiPF6 in EC / DMC (1:2) was used as the electrolyte and dropped between the separator and the electrode. The coin cell was then completely sealed to prevent electrolyte leakage.

[0051] Test Method The test method is a conventional "constant cutoff voltage" test. Conventional coin cell testing in this invention follows the schedule shown in Table 1. Each cell is cycled at 25°C using a Toscat-3100 computer-controlled galvanostatic cycling station (manufactured by Toyo Systems). This schedule uses a 1C current definition of 220 mA / g. The initial charge capacity (CQ1) and discharge capacity (DQ1) are measured in constant current mode (CC) at a C rate of 0.1C within the window range of 4.3V to 3.0V / Li metal.

[0052] The irreversible capacity IRRQ is expressed as a percentage as follows: IRRQ(%)=100×(CQ1-DQ1) / CQ1

[0053] [Table 1]

[0054] 2. Examples and Comparative Examples Comparative Example 1 A single crystal positive electrode active material labeled CEX (Comparative) 1.1 is prepared according to the following steps. Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.86 Mn 0.07 Co 0.07 A nickel-based transition metal oxide hydroxide powder (TMH1) having the formula (I) is prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. Step 2) Heating: The TMH1 prepared in step 1) is heated at 400°C for 7 hours in an oxidizing atmosphere to obtain a heated powder. Step 3) First Mixing: The heated powder prepared in step 2) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal ratio of 0.96. Step 4) First firing: The first mixture of step 3) is fired at 890°C for 11 hours in an oxidizing atmosphere to obtain a first fired powder. Step 5) Wet bead milling: The first calcined powder from step 4) is bead milled for 20 minutes with a solid to water weight ratio of 6:4, followed by filtering, drying, and sieving to obtain a milled powder. Step 6) Second Mixing: The milled powder from step 5) is mixed with LiOH in an industrial blender to obtain a second mixture with a lithium to metal ratio of 0.99. Step 7) Second calcination: The second mixture of step 6) is calcined at 760°C for 10 hours in an oxidizing atmosphere, followed by grinding and sieving to obtain a second calcined powder labeled CEX1.1.

[0055] Comparative Example 2 A single-crystal positive electrode active material, labeled CEX2, is prepared according to the following steps. Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.86 Mn 0.07 Co 0.07 Nickel-based transition metal oxide hydroxide powder (TMH2) having the formula (I) is prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. Step 2) Heating: The TMH2 prepared in step 1) is heated at 400°C for 7 hours in an oxidizing atmosphere to obtain a heated powder. Step 3) First Mixing: The heated powder prepared in step 2) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal ratio of 0.96. Step 4) First firing: The first mixture of step 3) is fired at 890°C for 11 hours in an oxidizing atmosphere to obtain a first fired powder. Step 5) Wet bead milling: The first calcined powder of 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 calcined powder, followed by drying and sieving to obtain a milled powder. The weight ratio of solid to solution for bead milling is 6:4, and the bead milling is carried out for 20 minutes. Step 6) Second Mixing: The milled powder obtained in step 5) is mixed in an industrial blender with 1.5 mol % Co from CO3O4 and 7.5 mol % Li from LiOH, each relative to the total molar content of Ni, Mn, and Co in the milled powder, to obtain a second mixture. Step 7) Second calcination: The second mixture of step 6) is calcined at 760°C for 10 hours in an oxidizing atmosphere, followed by grinding and sieving to obtain the second calcined powder, labeled CEX2.

[0056] Example 1 EX (Example) 1.0 is prepared according to the following method. Step 1) Mix CEX1.1 with WO3 powder to obtain a mixture containing approximately 0.45 wt% tungsten based on the total weight of the mixture. Step 2) The mixture obtained in step 1) is heated in a furnace under a flow of an oxidizing atmosphere at 350° C. for 10 hours. Step 3) The heated product of step 2) is ground and sieved to obtain a powder labeled EX1.0.

[0057] EX (Example) 1.1 is prepared according to the following method. Step 1) CEX2 is mixed with WO3 powder to obtain a mixture containing approximately 0.24 wt% tungsten based on the total weight of the mixture. Step 2) The mixture obtained in step 1) is heated in a furnace under a flow of an oxidizing atmosphere at 350° C. for 10 hours. Step 3) The heated product of step 2) is ground and sieved to obtain a powder labeled EX1.1.

[0058] EX1.2, EX1.3, EX1.4, EX1.5, EX1.6, and EX1.7 are prepared according to the same method as EX1.1, except that in step 1), CEX2 is mixed with WO powder to obtain mixtures containing about 0.36 wt%, 0.43 wt%, 0.45 wt%, 0.48 wt%, 0.75 wt%, and 1.50 wt%, respectively, of tungsten based on the total weight of the mixture.

[0059] EX1.8 and EX1.9 are prepared according to the same method as EX1.1, except that in step 1), CEX2 is mixed with WO powder to obtain a mixture containing about 0.36 wt. % tungsten relative to the total weight of the mixture, and the heating temperatures in step 2) are 300°C and 400°C, respectively.

[0060] Comparative Example 3 CEX3.1 is prepared according to the same method as EX1.1, except that in step 1), CEX2 is mixed with WO3 powder to obtain a mixture containing 3.00 wt. % tungsten relative to the total weight of the mixture.

[0061] CEX3.2 is prepared according to the same method as EX1.1, except that in step 1) CEX2 is mixed with WO powder so as to obtain a mixture containing about 0.36 wt. % tungsten relative to the total weight of the mixture, and in step 2) no heating is applied.

[0062] CEX3.3 is prepared according to the same method as EX1.1, except that in step 1) CEX2 is mixed with WO powder so as to obtain a mixture containing about 0.45 wt. % tungsten relative to the total weight of the mixture, and the heating temperature applied in step 2) is 550 °C.

[0063] The particle size distributions of the CEX1.1, CEX2, and EX1.3 products were determined by a Malvern Mastersizer 3000 as described in section 1.2 above. These products all have a median particle size D50 of 3.8-4.5 μm and D99 of 9.6 μm-11.1 μm.

[0064] Comparative Example 4 A polycrystalline positive electrode active material labeled CEX4.1 is prepared according to the following steps. Step 1) Preparation of transition metal oxide-hydroxide precursors: Two transition metal oxide-hydroxide precursors, labeled TMH3 and TMH4, respectively, were prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. The D50 of TMH3 was approximately 10 μm, and the D50 of TMH4 was approximately 4 μm. Both had Ni 0.65 Mn 0.20 Co 0.15 It has a metal composition of Step 2) First Mixing: The TMH3 and TMH4 obtained in Step 1) are mixed with LiOH and ZrO2 powders to obtain a first mixture. The TMH3 and TMH4 powders are mixed in a weight ratio of 7:3, the lithium-to-metal molar ratio is 1.03, and the Zr content in the mixture is 3700 ppm. Step 3) First calcination: The first mixture of step 2) is calcined at 870° C. for 12 hours in an oxidizing atmosphere to obtain a first calcined powder labeled CEX4.1.

[0065] CEX4.2 is prepared according to the following method. Step 1) Mix CEX4.1 with WO3 powder to obtain a mixture containing approximately 0.45 wt% tungsten based on the total weight of the mixture. Step 2) The mixture obtained in step 1) is heated in a furnace under a flow of oxidizing atmosphere at 400° C. for 7 hours. Step 3) The heated product of step 2) is ground and sieved to obtain a powder labeled CEX4.2.

[0066] Comparative Example 5 A single-crystal positive electrode active material labeled CEX5 is prepared according to the following steps. Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.68 Mn 0.20 Co 0.12 Nickel-based transition metal oxide hydroxide powder (TMH5) having the formula (I) is prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. Step 2) First Mixing: The TMH5 prepared in step 1) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal ratio of 0.97. Step 4) First firing: The first mixture of step 2) is fired at 920°C for 10 hours in an oxidizing atmosphere to obtain a first fired powder. Step 5) Jet Milling: The first calcined powder from step 4) is jet milled to obtain a milled powder labeled CEX5.

[0067] Example 2 A single crystal positive electrode active material labeled EX2 is prepared according to the following steps. Step 1) Mix CEX5 with WO3 powder to obtain a mixture containing approximately 0.45 wt% tungsten based on the total weight of the mixture. Step 2) The mixture obtained in step 1) is heated in a furnace under a flow of an oxidizing atmosphere at 350° C. for 10 hours. Step 3) The heated product of step 2) is ground and sieved to obtain a powder labeled EX2.

[0068] Comparative Example 6 A polycrystalline positive electrode active material labeled CEX6.1 is prepared according to the following steps. Step 1) Preparation of transition metal oxide hydroxide precursor: Metal composition Ni 0.80 Mn 0.10 Co 0.10A nickel-based transition metal oxide hydroxide powder (TMH6) having the formula (I) is prepared by co-precipitation in a large-scale continuous stirred tank reactor (CSTR) containing mixed nickel manganese cobalt sulfate, sodium hydroxide, and ammonia. Step 2) First heating: The TMH6 prepared in step 1) is heated at 375°C for 7 hours in an oxidizing atmosphere to obtain heated TMH6. Step 3) First Mixing: The heated TMH6 prepared in step 2) is mixed with LiOH in an industrial blender to obtain a first mixture with a lithium to metal ratio of 1.00. Step 4) Second heating: The first mixture of step 3) is calcined at 810°C for 12 hours in an oxidizing atmosphere, followed by grinding and sieving to obtain a calcined powder labeled CEX6.1.

[0069] CEX6.2 is prepared according to the following method. Step 1) Mix CEX6.1 with WO3 powder to obtain a mixture containing approximately 0.42 wt% tungsten based on the total weight of the mixture. Step 2) The mixture obtained in step 1) is heated in a furnace under a flow of oxidizing atmosphere at 285° C. for 8 hours. Step 3) The heated product of step 2) is ground and sieved to obtain a powder labeled CEX6.2.

[0070] The chemical compositions of the products of the examples and comparative counterexamples were determined by ICP-OES and are shown in Table 2, expressed as fractions compared to the total of Co, Ni, Mn and W.

[0071] Table 2 summarizes the compositions of the examples and comparative examples and their corresponding electrochemical properties. EX1.0 shows an improvement in DQ1 compared to CEX1.1, demonstrating the benefits of applying tungsten and heating according to the present invention. Similarly, EX1.4 shows a higher DQ1 compared to CEX2.

[0072] [Table 2]

[0073] * Expressed as a fraction of (Co+Ni+Mn+W) ** It is determined by ICP-OES measurement and expressed as a percentage compared to the total weight of the product. *** Determined by XRD analysis -: Not applicable

[0074] EX1.1 to EX1.7 and CEX3.1 each contain different amounts of tungsten, but are heated at the same temperature of 350°C. It has been shown that the objectives of the present invention are effectively achieved over a range of concentrations from 0.26 wt% for EX1.1 to 1.42 wt% for EX1.7. In contrast, CEX3.1, which contains 2.92 wt% tungsten, exhibits a DQ1 decrease from 198.1 mAh / g for CEX2, which contains no tungsten, to 196.7 mAh / g.

[0075] EX1.8, EX1.9, CEX3.2, and CEX3.3 demonstrate the effect of heating temperature on a cathode active material containing a tungsten source. It is shown that the objectives of the present invention can be effectively achieved at heating temperatures ranging from 300°C (EX1.8) to 400°C (EX1.9). In contrast, CEX3.2 (unheated) and CEX3.3 (heated at 550°C) exhibited low DQ1 values ​​of 193.3 mAh / g and 186.5 mAh / g, respectively. This result demonstrates that heating after tungsten addition is essential, provided the temperature is kept below 550°C.

[0076] CEX4.1 and CEX4.2 are positive electrode active materials with a polycrystalline morphology containing 65 mol% Ni. CEX4.2 further contains 0.45 wt% tungsten, but does not show an improvement in DQ1 compared to CEX4.1. CEX6.1 and CEX6.2 are positive electrode active materials with a polycrystalline morphology containing 80 mol% Ni, with CEX6.2 further containing 0.42 wt% tungsten. Similarly, the DQ1 of CEX6.2 is not improved compared to CEX6.1. It is observed that the polycrystalline morphology is not suitable for achieving an improvement in DQ1, even when the total Ni content in the material is higher. On the other hand, EX2, which has a single crystalline morphology containing 68 mol% and 0.45 wt% tungsten, shows an improvement in DQ1 compared to CEX5, which contains the same amount of Ni.

[0077] X-ray diffraction analysis was performed to identify the tungsten phase corresponding to the heating temperature. Figure 1 shows the XRD pattern of EX1.7, which shows three phases: R-3m (LiNi 0.86 Mn 0.07 Co 0.07 1 shows that the SiO2 nanoparticles have a first compound phase of Li2WO4 according to the present invention, a second compound phase of WO3, and a third compound phase of Li2WO2, R-3 (a first compound phase of Li2WO4 according to the present invention), and P21 / n (a second compound phase of WO3).

[0078] Figure 2 shows the XRD patterns of CEX3.3, CEX1.4, and CEX2. CEX2 and CEX3.3 have XRD patterns related to the R-3m phase. According to "Journal of Power Sources (2000), 90, 76-81," the XRD patterns indicate that CEX2 and CEX3.3 are lithium transition metal oxide compounds. They are LiNi 0.86 Mn 0.07 Co 0.07 As explained in Figure 1, EX1.4 has the general formula of LiNi 0.86 Mn 0.07 Co 0.07The graph shows the R-3m, R-3, and P21 / n phases corresponding to O2, Li2WO4, and WO3. This result indicates that a heating temperature of 350°C is suitable for producing the first and second compound phases according to the present invention. The presence of the R-3m, R-3, and P21 / n phases in the positive electrode active material improves the electrochemical properties.

Claims

1. 1. A cathode active material for a lithium ionic liquid electrolyte rechargeable battery, the cathode active material being a powder, the powder comprising a third compound comprising Li, M′, and O, wherein M′ is: Co with a content x of 2.0 mol % or more and 35.0 mol % or less relative to M'; Mn having a content y of 0 mol% or more and 35.0 mol% or less relative to M'; A has a content m of 0 mol % or more and 5 mol % or less relative to M', and contains at least one element selected from the group consisting of Al, Ba, B, Mg, Nb, Sr, Ti, W, S, Ca, Cr, Zn, V, Y, Si, and Zr; a third compound consisting of (100-x-y-m) mol % Ni, i. Li ２ WO ４ a first compound comprising: ii. WO ３ a powder comprising a second compound comprising: The powder consists of up to five constituent grains, the positive electrode active material comprises Li in a molar ratio of Li / (Co+Mn+Ni+A) of at least 0.900 and at most 1.100; The positive electrode active material has a median particle size D50 of 2 μm to 7 μm as determined by laser diffraction particle size distribution analysis.

2. 2. The positive electrode active material according to claim 1, wherein the first compound has a crystal structure belonging to space group R-3 and the second compound has a crystal structure belonging to space group P21 / n, as determined by X-ray diffraction analysis.

3. 10. The cathode active material of claim 1, wherein a total tungsten content is 0.20 wt % to 2.50 wt %, based on the total weight of the cathode active material, as determined by ICP-OES analysis.

4. 4. The cathode active material of claim 1, wherein the total tungsten content is 0.30 wt % to 2.00 wt %, based on the total weight of the cathode active material, as determined by ICP-OES analysis.

5. 5. The cathode active material according to claim 1, wherein the cathode active material has a size D99 of at least 5 μm and at most 25 μm, as determined by laser diffraction particle size distribution analysis.

6. 6. The cathode active material according to claim 1, wherein the cathode active material has a size D99 of at least 7 μm and at most 20 μm, as determined by laser diffraction particle size distribution analysis.

7. 7. The positive electrode active material according to claim 1, wherein m is 2.0 mol % or less relative to M'.

8. The first compound is Li ２ WO ４ The positive electrode active material according to any one of claims 1 to 7,

9. The second compound is WO ３ The positive electrode active material according to any one of claims 1 to 8.

10. 10. The positive electrode active material according to claim 1, wherein the Ni content (100-xym) is 60 mol % to 95 mol % relative to M'.

11. A lithium ion rechargeable battery comprising the positive electrode active material according to any one of claims 1 to 10.

12. A battery cell comprising the positive electrode active material according to any one of claims 1 to 10.

13. Use of the positive electrode active material according to any one of claims 1 to 10 in a battery of any one of a portable computer, a tablet, a mobile phone, an electric vehicle, and an energy storage system.

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