Tungsten-containing tm-hydroxide or -oxyhydroxide powder material, method for preparing the same and method for preparing positive electrode active material using the same

Abstract

It is disclosed a method for preparing a tungsten-containing TM-hydroxide or -oxyhydroxide powder material for positive electrode active material for secondary batteries, the method comprising: a) providing TM'-based hydroxide or oxyhydroxide particulate material, wherein the TM' refers to a combination of nickel and at least one metal selected from Co and Mn; b) providing an aqueous solution of tungsten oxide, c) combining the TM'-based particulate material and the aqueous solution of tungsten oxide to obtain a slurry, preferably the slurry being alkaline; and d) recovering a solid fraction from the slurry to obtain the tungsten-containing TM hydroxide or oxyhydroxide powder material.

Description

[0001] TUNGSTEN-CONTAINING TM-HYDROXIDE OR -OXYHYDROXIDE POWDER MATERIAL, METHOD FOR PREPARING THE SAME AND METHOD FOR PREPARING POSITIVE ELECTRODE ACTIVE MATERIAL USING THE SAME

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to a tungsten-containing TM hydroxide or oxyhydroxide powder material for preparing a positive electrode active material for secondary batteries. It also relates to a method for preparing the same and a method for preparing a positive electrode active material by using the same.

[0004] BACKGROUND

[0005] Lithium-ion secondary batteries typically include a negative electrode (anode), an electrolyte, and a positive electrode (cathode) that contains a lithium-transition metal oxide as an active material capable of insertion and desorption of lithium. Lithium-transition metal oxides are generally manufactured from transition-metal hydroxides, oxides or oxyhydroxides manufactured typically in turn in co-precipitation processes that involve the admixing of a metal salt solution and an alkali solution, with the potentially inclusion of a complexing agent.

[0006] To obtain a lithium-ion secondary battery with an excellent energy density and cycling lifetime, the positive electrode active material must have high charge and discharge capacity and good thermal stability. For instance, Ni-rich layered cathodes are advantageous in terms of energy density and material cost, in general, but they have considerably decreased cycling lifetimes with inferior thermal stabilities. Recently, it has been discovered that tungsten (W) doping can overcome the inherent structural instability of Ni-rich cathode material and considerably improve its cycling stability and thermal properties without compromising the capacity. Several techniques have been proposed in the art to provide tungsten-containing cathode material, including a wet-impregnation doping approach for hydroxide precursor material or solid-state approaches, such as dry-doping during mixing the precursor material with lithium source. The former-type approaches may result in a more homogeneous tungsten distribution within the material compared to the solid-state approaches. However, one challenge for these methods is that the carbon content of the precursor material increases due to the carbon being introduced in the tungsten wet-impregnation process. The carbon introduced during the pCAM manufacturing process should be avoided as it remains in the positive electrode active material produced from it. Carbon in the positive electrode active material reacts with the electrolyte in a secondary battery, resulting in disadvantages such as low energy density and poor cycle life.

[0007] In light of the aforementioned considerations, it is evident that further enhancements are necessary for tungsten wet-impregnation processes involving precursor materials. SUMMARY OF THE INVENTION

[0008] It is a first object of the present invention to provide a method for preparing a tungsten- containing TM-hydroxide or -oxyhydroxide powder material for positive electrode active material for secondary batteries.

[0009] It is a second object of the present invention to provide a tungsten-containing TM- hydroxide or -oxyhydroxide powder material for preparing a positive electrode active material for secondary batteries.

[0010] It is a third object of the present invention to provide a method for preparing a positive electrode active material by using the tungsten-containing TM-hydroxide or -oxyhydroxide powder material.

[0011] In a first aspect, the first object of the invention is achieved by providing a method for preparing a tungsten-containing TM hydroxide or oxyhydroxide powder material for positive electrode active material for secondary batteries according to claim 1. The method comprising: a) providing TM'-based hydroxide or oxyhydroxide particulate material comprising secondary particles, wherein the secondary particles comprise of a plurality of primary particles and grain boundaries between the primary particles; b) providing an aqueous solution of tungsten oxide, c) combining the TM'-based particulate material and the aqueous solution of tungsten oxide to obtain a slurry, preferably the slurry being alkaline; and d) recovering a solid fraction from the slurry to obtain the tungsten-containing TM hydroxide or oxyhydroxide powder material wherein the TM' refers to a combination of the metals with the following content:

[0012] - Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM';

[0013] - Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM';

[0014] - Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM'; and

[0015] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%; or to a combination of the metals with the following content:

[0016] - Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM';

[0017] - Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM';

[0018] - Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM'; and

[0019] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%. The particulate material provided in step a) is composed of secondary particles, which are themselves comprised of a plurality of primary particles.

[0020] As the aqueous solution of tungsten oxide is devoid of alcohol or any other carbon-based solution, the tungsten-impregnation process according to the first aspect of the invention introducing a carbon source during the preparation of the TM hydroxide or oxyhydroxide powder material can be avoided or at least lessened compared to the known tungsten wetimpregnation processes.

[0021] As demonstrated by Examples 1 and Comparative Example 1, the carbon content of the material obtained by the first aspect of the invention is less than that of the respective material obtained by the known tungsten wet-impregnation process.

[0022] In a second aspect, the second object of the invention is achieved by providing a tungsten-containing TM hydroxide or oxyhydroxide powder material for preparing a positive electrode active material for secondary batteries, wherein the material comprises secondary particles comprising of a plurality of primary particles, wherein a grain boundary is present between adjacent primary particles of the secondary particles, wherein a concentration of tungsten in the grain boundary is greater than a concentration of tungsten in the adjacent primary particles, and wherein the carbon content of the material being equal to or less than 800 ppm, preferably being equal to or less than 700 ppm, wherein the TM refers to either a combination of the metals with the following content:

[0023] - Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM;

[0024] - Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM;

[0025] - Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM;

[0026] - W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and

[0027] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%, or to a combination of the metals with the following content:

[0028] - Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM;

[0029] - Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM;

[0030] - Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM;

[0031] - W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and

[0032] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%..

[0033] In a third aspect, the third object of the invention is achieved by providing a method for preparing a positive electrode active material, comprising the steps of: - mixing a tungsten-containing TM hydroxide or oxyhydroxide powder material manufactured according to the first aspect or a tungsten-containing TM hydroxide or oxyhydroxide powder material according to the second aspect, a lithium source, and optionally a second dopant source, to obtain a mixture, preferably wherein the second dopant is aluminum oxide (AI2O3);

[0034] - heating the mixture in oxidizing atmosphere at a temperature between 650 °C to 1000 °C to obtain the positive electrode active material, and optionally;

[0035] - the method further comprising a heat treatment step before the mixing, wherein the powder material is heated at a temperature of 105 °C to 750 °C.

[0036] Various embodiments according to the present invention are disclosed in the claims as well as in the description. The embodiments and examples recited in the claims and in the description are mutually freely combinable unless otherwise explicitly stated. Throughout the entire disclosure, if any numerical ranges are provided, the ranges also include the endpoint values unless otherwise explicitly stated.

[0037] In the following, embodiments of the invention are explained in more detail based on the figures. Identical reference signs thereby refer to identical or corresponding elements and their unnecessary redescription has been avoided.

[0038] BRIEF DESCRIPTION OF THE FIGURES

[0039] By means of further guidance, figures are included to better appreciate the teaching of the present invention, wherein:

[0040] Figure 1 is a collection of images of precursor EXI obtained from Example 1, where figure (A) on the left is a TEM image of a FIB-cut lamella containing three highlighted imaging maps 1, 2 and 3 from the top region, middle region, and center region of the particle, respectively, and figures (la)-(3b) on the right are images of HAADF-STEM and tungsten STEM-EDS from the respective imaging map indicated by the arrow.

[0041] DETAILED DESCRIPTION OF THE INVENTION

[0042] In the following detailed description, preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. To the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description and accompanying drawings.

[0043] The term "comprising", as used herein and in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to compositions consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the composition are A and B. Accordingly, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of".

[0044] TEM stands for Transmission Electron Microscopy or Transmission Electron Microscope . FIB stands for Focused Ion Beam, HAADF-STEM stands for High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy, and STEM-EDS stands for Scanning Transmission Electron Microscopy with Energy Dispersive X-ray Spectroscopy.

[0045] Method for Preparing Tungsten-containing TM-Hydroxide or -Oxyhydroxide Powder Material In a first aspect, the present invention relates to a method of preparing a tungsten-containing TM hydroxide or oxyhydroxide powder material (in this disclosure, may be abbreviated as a positive electrode active material precursor or as a precursor material or as precursor, respectively) for positive electrode active material for secondary batteries, wherein the method comprises consecutive steps of: a) providing TM'-based hydroxide or oxyhydroxide particulate material, comprising secondary particles, wherein the secondary particles comprise of a plurality of primary particles and grain boundaries between the primary particles; b) providing an aqueous solution of tungsten oxide; c) combining the TM'-based particulate material and the aqueous solution of tungsten oxide to obtain a slurry, preferably the slurry being alkaline; and d) recovering a solid fraction from the slurry to obtain the tungsten-containing TM hydroxide or oxyhydroxide powder material.

[0046] In the method the TM'-based particulate material comprises secondary particles, wherein the secondary particles comprise of a plurality of primary particles . Grain boundaries are formed in-between the primary particles. In the step c) the secondary particles may thus be impregnated with the aqueous solution of tungsten oxide. In other words, in the step c) the grain boundaries within the secondary particles may be impregnated with the aqueous solution of tungsten oxide.

[0047] The grain boundaries are located in between primary particles on a surface of the primary particles ( / .e., crystallites). Thus, the shape of the grain boundary is defined by the shape of the primary particles adjacent to the grain boundary and may approximate a rectilinear shape or irregular such as a polygon when viewed in cross-section.

[0048] The dimensions of the grain boundary are not particularly limited. A length and a width of the grain boundary may each independently be about 50 nm to about 1000 nm, preferably about 60 nm to about 900 nm, and more preferably about 70 nm to about 800 nm, when viewed in cross-section. The length and width of the grain boundaries may be perpendicular to each other and may be parallel to the surface of the adjacent crystallite. A thickness of the grain boundary may be about 1 nm to about 100 nm, preferably about 2 nm to about 80 nm, and more preferably about 5 nm to about 50 nm. The thickness of the grain boundary may be perpendicular to the length and the width of the grain boundary and may be perpendicular to the surface of the adjacent crystallite. The thickness of the grain boundary is defined by the W concentration profile through a line scan crossing the grain boundary, for instance. The W concentration profiles may be obtained by Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-ray Spectroscopy (EDX / EDS) measurement.

[0049] The inventors of the present invention have found that the carbon content of the obtained tungsten-containing precursor material according to the invention is smaller than the carbon content of the precursor material obtained by a wet-impregnation doping approach for hydroxide precursor material according to the known method.

[0050] In an embodiment of the method, the TM'-based particulate material has a median particle size of D50 in the range of 3.0 pm to 20.0 pm.

[0051] In an embodiment, the TM' refers to a combination of the metals with the following content:

[0052] Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM';

[0053] Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM';

[0054] Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM'; and at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%, and wherein x, y, z, and t are measured by ICP-OES.

[0055] In an embodiment, the TM' refers to a combination of the metals with the following content:

[0056] - Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM';

[0057] - Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM';

[0058] - Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM'; and

[0059] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%, and wherein x, y, z, and t are measured by ICP-OES.

[0060] In an embodiment, the recovering in the step d) comprising drying the solid fraction, preferably at a temperature below 650 °C or below 400 °C or below 200 °C.

[0061] In an embodiment, the drying comprises purging inert gas, such as N2 gas, through a vessel enclosing the solid fraction.

[0062] In an embodiment, the method further comprises keeping the slurry obtained in step c) in vacuum, preceding the step d), preferably at least 0.25 hour or 0.5 hour or 1 hour. In an embodiment, the providing an aqueous solution of tungsten oxide in the step b) comprises dissolving a tungsten source, preferably tungsten trioxide (WO3), in an alkaline aqueous solution to form the aqueous solution of tungsten oxide.

[0063] In an embodiment, the providing an aqueous solution of tungsten oxide in the step b) comprises adding a base to the combination of the tungsten trioxide and the aqueous solution, such as water, to form the aqueous solution of tungsten oxide. Preferably the base comprises one or more alkaline hydroxides such as lithium hydroxide (LiOH). In one embodiment the base comprises LiOH.

[0064] In an embodiment, the providing an aqueous solution of tungsten oxide in the step b) comprises increasing the pH value of the combination of the tungsten trioxide and the aqueous solution to at least 11.5 or 12.0 or 12.5 or 12.7 to form the aqueous solution of tungsten oxide, where the provided tungsten source, such as WO3, being dissolved.

[0065] In an embodiment, the TM'-based particulate material and the aqueous solution of tungsten oxide are combined in step c) in such a way that the weight ratio of W to the TM'- based particulate material is at least 0.5 % or advantageously at least 1.0 % , calculated by dividing the mass of W with the mass of the particulate material. If the ratio is less than 0.5%, there is a risk that the amount of W impregnated into the particulate material in step c) may not be sufficient to sufficiently enrich the grain boundaries of the material.

[0066] In an embodiment in which the tungsten source is WO3, the amount of WO3 is determined such that the weight of W with respect to the total weight of TM'-based particulate material would be at least 1000 ppm or at least 3000 ppm or at least 5000 ppm or at least 7000 ppm.

[0067] If the LiOH is used to form the aqueous solution of tungsten oxide, then as appreciated by the skilled person, the amount of LiOH added in step c) is preferably deducted and taken into account in the subsequent cathode material preparation step when blending a lithium source with the precursor material to obtain a desired lithium to metal ratio for the positive electrode active material obtained.

[0068] Tungsten-containing TM-Hydroxide or -Oxyhydroxide Powder Material

[0069] In a second aspect, the present invention relates to a tungsten-containing TM-hydroxide or - oxyhydroxide powder material for preparing a positive electrode active material for secondary batteries, wherein the TM refers to a combination of at least nickel and tungsten and at least one metal selected from Co and Mn, wherein the material comprises secondary particles comprising of a plurality of primary particles, wherein a grain boundary is present between adjacent primary particles of the secondary particles, wherein a concentration of tungsten in the grain boundary is greater than a concentration of tungsten in the adjacent primary particles, and wherein the carbon content of the material being equal to or less than 800 ppm, preferably being equal to or less than 700 ppm. In an embodiment, the TM of the material of the second aspect refers to a combination of the metals with the following content:

[0070] - Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM;

[0071] - Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM;

[0072] - Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM;

[0073] - W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and

[0074] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%, and wherein x, y, z, a, and t are measured by ICP-OES.

[0075] In an embodiment, the TM of the material of the second aspect refers to a combination of the metals with the following content:

[0076] - Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM;

[0077] - Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM;

[0078] - Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM;

[0079] - W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and

[0080] - at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%, and wherein x, y, z, a, and t are measured by ICP-OES.

[0081] In an embodiment, the material of the second aspect has a median particle size D50 in the range of 3.0 pm to 20.0 pm.

[0082] Method for Preparing Positive electrode active Material

[0083] In a third aspect, the present invention relates to a method for preparing a positive electrode active material, comprising the steps of:

[0084] - mixing a tungsten doped TM hydroxide or oxyhydroxide powder material manufactured according to the first aspect of the invention or a tungsten doped TM hydroxide or oxyhydroxide powder material according to the second aspect of the invention, a lithium source, and optionally a second dopant source, to obtain a mixture, preferably wherein the second dopant is aluminum oxide (AI2O3) ;

[0085] - heating the mixture in oxidizing atmosphere at a temperature between 650 °C to 1000 °C to obtain the positive electrode active material, and optionally;

[0086] - the method further comprising a heat treatment step before the mixing, wherein the powder material is heated at a temperature of 105 °C to 750 °C.

[0087] The present disclosure further concerns a secondary battery comprising a positive electrode active material, prepared according to any one of the embodiments or combination of embodiments of the method according to the first aspect of the present invention. The present disclosure further concerns the use of such a secondary battery according to claim 14 in an electrical vehicle or in a hybrid electrical vehicle. EXPERIMENTAL TESTS USED IN THE EXAMPLES

[0088] The following analysis methods are used in the Examples:

[0089] A) Particle size distribution (PSD) analysis

[0090] The PSD is measured using a Malvern Mastersizer 3000 with Hydro MV wet dispersion accessory after dispersing examples as described herein below of positive electrode active material powders in an aqueous medium. To improve the dispersion of the positive electrode active material powder examples, sufficient ultrasonic irradiation and stirring is applied, and an appropriate surfactant is introduced. D50 is defined as the particle size at 50% of the cumulative volume % distribution.

[0091] B) Inductively coupled plasma - optical emission analysis (ICP-OES) analysis

[0092] The W content in the TM precursor and the positive electrode active material examples as described herein below are measured by the Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) method using an Agillent ICP 720-OES. 1 gram of a powder sample of each example is dissolved into 50 mL high purity hydrochloric acid in an Erlenmeyer flask. The flask is covered by a watch glass and heated on a hot plate at 380 °C until complete dissolution of the sample. After being cooled to room temperature, the solution and the rinsing water of Erlenmeyer flask are transferred to a 250 mL volumetric flask. Afterwards, the volumetric flask is filled with DI water up to the 250 mL mark, followed by complete homogenization. An appropriate amount of solution is taken out by pipette and transferred into a 250 mL volumetric flask for the 2nddilution, where the volumetric flask is filled with internal standard and 10 % hydrochloric acid up to the 250 mL mark and then homogenized. Finally, this solution is used for ICP-OES measurement.

[0093] C) Carbon analysis

[0094] The content of carbon of the positive electrode active material powder and the TM precursor powder are measured by Horiba Emia-Expert carbon / sulfur analyzer. 1 gram of the positive electrode active material powder is placed in a ceramic crucible in a high frequency induction furnace. 1.5 grams of tungsten and 0.2 grams of tin are added into the crucible as accelerators. The powder is heated at a programmable temperature wherein gases produced during the combustion are then analyzed by Infrared detectors. The analysis of CO2 and CO determines the carbon concentration.

[0095] D) Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X- ray Spectroscopy (EDS) measurement

[0096] To prepare a lamella for cross-sectional Scanning Transmission Electron Microscopy (STEM) and Energy Dispersive X-ray Spectroscopy (EDS), the TM precursor sample is coated with 25 nm layer of carbon (Leica EM ACE600 coater) before Focused Ion Beam (FIB) preparation. FIB lamella is prepared on a Cu Omniprobe TEM grid, using a Thermo Fisher Helios FIB-SEM with Ga ion beam first at 30 kV, then at 8 kV and at the final thinning step at 2 kV and 39 pA.

[0097] The lamella size is about 4.2 x 6.6 um, the thickness is about 50-100 nm.

[0098] The lamella is transferred to the Ar filled glove box in the vacuum transfer box. The TEM vacuum transfer holder (Gatan) is assembled in the glove box. The High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM) and Energy Dispersive X-ray spectroscopy (EDS) are performed on an aberration corrected FEI Titan transmission electron microscope at 300 kV, using a Super X detector. The screen current is 150 pA with acquisition time of 20 min in the map size of 570x570 nm.

[0099] For EDX map scans acquisition and data processing, Esprit Quantax software version 1.9, Bruker, is used. For line scan profiles, the following elements were considered: Ni (Ni-K line at 7.47 keV), Mn (Mn-K line at 5.90 keV), Co (Co-K line at 6.93 keV) and W (W-M line at 1.78 keV).

[0100] EXAMPLES

[0101] The present invention is further illustrated in the following examples:

[0102] Preparation Example 1: A TM-based hydroxide or oxyhydroxide powder material, i.e., a transition metal-based precursor for positive electrode active material, further called as precursor pEXl, is prepared according to the following steps:

[0103] 1) Co-precipitation: Precursor pEXl with a metal composition of Ni0.94Mn0.03Co0.03 is prepared by a co-precipitation process in a stirred tank reactor. The precipitation is continued by feeding an aqueous solution containing dissolved nickel-manganese-cobalt sulfates in a molar ratio of Ni:Mn :Co of 0.94:0.03:0.03 and aqueous solutions of sodium hydroxide and ammonia into the reactor until the median particle size, D50, of the aqueous slurry obtained reached approximately 15 pm to 17 pm.

[0104] 2) Post-processing: precursor pEXl is then obtained by washing and filtering the solids from the slurry, followed by drying.

[0105] Example 1: An example of tungsten-containing TM hydroxide or oxyhydroxide powder material, i.e., a tungsten-containing transition metal-based precursor, further called as precursor EXI, is prepared according to the following steps:

[0106] 1) 45 mL of deionized water and 2.42 g of tungsten trioxide (WO3) are added to an Erlenmeyer flask, followed by the addition of 1 g of pellets of lithium hydroxide (LiOH) until obtaining a complete dissolution of the WO3 occurs, around the pH of 12.7 (measured at room temperature).

[0107] 2) 180 g of the precursor pEXl prepared from Preparation Example 1 and the aqueous solution of tungsten trioxide prepared from step 1) are added to a 400 mL unbaffled washing reactor equipped with an overhead stirrer. This is followed by stirring at 200 rpm for 15 minutes to form a slurry which is vacuum dried at 120°C for 10 hours to obtain precursor EXI. The tungsten and carbon contents of the obtained precursor EXI were analyzed by the methods described above and the tungsten content of 7350 ppm and the carbon content of 680 ppm, respectively, was obtained. Figure 1 shows a collection of images of precursor EXI, where figure (A) on the left is a TEM image of a FIB-cut lamella containing three highlighted imaging maps 1, 2 and 3 from the surface region, middle region, and center region of the particle, respectively, and figures (la)-(3b) on the right are images of HAADF-STEM and tungsten STEM-EDS from the respective imaging map indicated by the arrow.

[0108] Comparative Example 1: A comparative example of tungsten-containing TM precursor, further called as precursor CEX1, is prepared according to the following steps:

[0109] 1) 30g of precursor pEXl, prepared from preparation example, is mixed with 10.8 mL of ethanol solution containing 5 wt.% w / v of tungsten (VI) ethoxide. The amount of tungsten (VI) ethoxide is determined such that the content of W with respect to the total weight of precursor CEX1 would be 7000 ppm.

[0110] 2) The mixture was stirred for 3 minutes and dried for 10 minutes. The ethanol is then evaporated under inert conditions, followed by drying at 80 °C for 15 hours under N2 gas atmosphere so as to obtain the precursor CEX1.

[0111] The tungsten and carbon contents of the obtained precursor CEX1 were analyzed by the methods described above and the tungsten content of 1120 ppm and the carbon content of 986 ppm, respectively, was obtained.

Claims

CLAIMS1. A method for preparing a tungsten-containing TM-hydroxide or -oxyhydroxide powder material for positive electrode active material for secondary batteries, the method comprising : a) providing TM'-based hydroxide or oxyhydroxide particulate material comprising secondary particles, wherein the secondary particles comprise of a plurality of primary particles and grain boundaries between the primary particles; b) providing an aqueous solution of tungsten oxide; c) combining the TM'-based particulate material and the aqueous solution of tungsten oxide to obtain a slurry, preferably the slurry being alkaline; and d) recovering a solid fraction from the slurry to obtain the tungsten-containing TM hydroxide or oxyhydroxide powder material; wherein the TM' refers to either a combination of the metals with the following content:- Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM';- Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM';- Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM'; and- at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%; or to a combination of the metals with the following content:- Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM';- Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM';- Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM'; and- at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM', wherein x+y+z+t is 100.0 mol%.

2. The method of claim 1, wherein in the step a) the TM'-based particulate material has a median particle size of D50 in the range of 3.0 pm to 20.0 pm.

3. The method of any of the preceding claims, wherein the recovering in the step d) comprising drying the solid fraction, preferably at a temperature below 650 °C or below 400 °C or below 200 °C.

4. The method of claim 3, wherein the drying comprising purging inert gas, such as N2 gas, through a vessel enclosing the solid fraction.

5. The method of any of the preceding claims, comprising keeping the slurry obtained in step c) in vacuum, preceding the step d), preferably at least 0.25 hour or 0.5 hour or 1 hour.

6. The method of any of the preceding claims, wherein the providing an aqueous solution of tungsten oxide in the step b) comprises dissolving a tungsten source, preferably tungsten trioxide WO3, in an alkaline aqueous solution to form the aqueous solution of tungsten oxide.

7. The method of claim 6, wherein step b) comprises adding an alkaline hydroxides to the solution, preferably lithium hydroxide LiOH.

8. The method of claim 6 or 7, wherein step b) comprises increasing the pH value of the combination of the tungsten trioxide and the aqueous solution to at least 11.5 or 12.0 or 12.5 or 12.7 to form the aqueous solution of tungsten oxide.

9. Method according to any one preceding claim wherein the TM'-based particulate material and the aqueous solution of tungsten oxide are combined in step c) in such a way that the weight ratio of W to the TM'-based particulate material is at least 0.5 % or advantageously at least 1.0 %.

10. Method according to any one preceding claim wherein the amount of WO3 provided in step b) determined such that the weight of W with respect to the total weight of TM'-based particulate material would be at least 1000 ppm or at least 3000 ppm or at least 5000 ppm or at least 7000 ppm.

11. A tungsten-containing TM-hydroxide or -oxyhydroxide powder material for preparing a positive electrode active material for secondary batteries, wherein the material comprises secondary particles comprising of a plurality of primary particles, wherein a grain boundary is present between adjacent primary particles of the secondary particles, wherein a concentration of tungsten in the grain boundary is greater than a concentration of tungsten in the adjacent primary particles, wherein the carbon content of the material is equal to or less than 800 ppm, preferably being equal to or less than 700 ppm, and wherein the TM refers to either a combination of the metals with the following content:- Ni in a content x, wherein 60.0 < x < 96.0 mol%, relative to TM;- Mn in a content y, wherein 0.0 < y < 20.0 mol%, relative to TM;- Co in a content z, wherein 1.0 < z < 20.0 mol%, relative to TM;- W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and- at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%, or to a combination of the metals with the following content:- Ni in a content x, wherein 15.0 < x < 40.0 mol%, relative to TM;- Mn in a content y, wherein 60.0 < y < 85.0 mol%, relative to TM;- Co in a content z, wherein 0.0 < z < 20.0 mol%, relative to TM;- W in a content a, wherein 0.0 < a < 2.0 mol%, relative to TM; and- at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, and Ta, in a content t, 0.0 < t < 10.0 mol%, relative to TM, wherein x+y+z+a+t is 100.0 mol%.

12. The material of claim 10 having a median particle size D50 in the range of 3.0 pm to 20.0 pm.

13. A method for preparing a positive electrode active material, comprising the steps of:- mixing o a tungsten-containing TM-hydroxide or -oxyhydroxide powder material manufactured according to any of claims 1 to 9 or a tungsten-containing TM- hydroxide or -oxyhydroxide powder material according to claim 10, o a lithium source, and o optionally a dopant source, wherein the dopant preferably is aluminum oxide (AI2O3) to obtain a mixture, ;- heating the mixture in an oxidizing atmosphere at a temperature between 650 °C to 1000 °C to obtain the positive electrode active material, and optionally;- the method further comprising a heat treatment step before the mixing, wherein the powder material is heated at a temperature of 105 °C to 750 °C.

14. A secondary battery comprising a positive electrode active material, prepared according to any one of clams 1 to 10.

15. Use of a secondary battery according to claim 14 in an electrical vehicle or in a hybrid electrical vehicle.

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