Process for making precursors of cathode active materials, and precursors

Abstract

Process for making a particulate (oxy)hydroxide or oxide of TM, wherein TM is a combination of metals of which at least 94 mol-% are transition metals and TM comprises nickel and at least one metal selected from cobalt and manganese and aluminum, wherein said process comprises the steps of: (a) providing aqueous solution(s) (a) containing a water-soluble salt of nickel and at least one metal selected from cobalt and manganese and aluminum, and (p) an aqueous solution containing an alkali hydroxide and, optionally, (y) an aqueous solution containing a complexing agent selected from ammonia, glycine, tartrate, citrate, and oxalate, (b) combining solution(s) (a) and solution (p) and, if applicable, solution (y), at a pH value in the range of from 9.0 to 13.5 in one or more sub-steps, thereby precipitating a hydroxide of TM in particulate form, (c) recovering hydroxide of TM in particulate form through a solid-liquid-separation step, thereby obtaining solid particles of (oxy)hydroxide of TM, (d) mechanically treating the solid particles of hydroxide of TM or the respective oxide or oxyhydroxide with a peak energy input in the range of from 30 W to 250 kW, thereby adapting the surface profile without significantly changing the average particle size, (e) and, optionally, removing water by a thermal treatment at a temperature in the range of from 400 to 600°C.

Description

[0001] Process for making precursors of cathode active materials, and precursors

[0002] The present invention is directed towards a process for making a particulate (oxy)hydroxide or oxide of TM, wherein TM is a combination of metals of which at least 94 mol-% are transition metals and TM comprises nickel and at least one metal selected from cobalt and manganese and aluminum, wherein said process comprises the steps of:

[0003] (a) providing aqueous solution(s) (a) containing a water-soluble salt of nickel and at least one metal selected from cobalt and manganese and aluminum, and an aqueous solution (p) containing an alkali hydroxide and, optionally, an aqueous solution (y) containing a complexing agent selected from ammonia, glycine, tartrate, citrate, and oxalate,

[0004] (b) combining solution(s) (a) and solution (p) and, if applicable, solution (y), at a pH value in the range of from 9.0 to 13.5 in one or more sub-steps, thereby precipitating a hydroxide of TM in particulate form,

[0005] (c) recovering hydroxide of TM in particulate form through a solid-liquid-separation step, thereby obtaining solid particles of (oxy)hydroxide of TM,

[0006] (d) mechanically treating the solid particles of hydroxide of TM or the respective oxide or oxyhydroxide with a peak energy input in the range of from 30 W to 250 kW, thereby adapting the surface profile without significantly changing the average particle size,

[0007] (e) and, optionally, removing water by a thermal treatment at a temperature in the range of from 400 to 600°C.

[0008] Lithiated transition metal oxides are currently being used as electrode active materials for lithium-ion batteries. Extensive research and developmental work have been performed in the past years to improve properties like charge density, specific energy, but also other properties like the reduced cycle life and capacity loss that may adversely affect the lifetime or applicability of a lithium-ion battery. Additional effort has been made to improve manufacturing methods.

[0009] In a typical process for making cathode materials for lithium-ion batteries, first a so-called precursor is being formed by co-precipitating the transition metals preferably as hydroxides that may or may not be basic, for example oxyhydroxides. Hydroxides may be pre-calcined and turned into oxides or oxyhydroxides, or they are directly mixed with a source of lithium such as, but not limited to LIOH, Li2O, l_i2C>2 or l_i2CC>3 and calcined (fired) at high temperatures. The source of lithium can be employed as hydrate(s) or in dehydrated form. The calcination - or firing - often also referred to as thermal treatment or heat treatment of the precursor - is usually carried out at temperatures in the range of from 600 to 1000 °C. During the thermal treatment a solid-state reaction takes place, and the electrode active material is formed. The thermal treatment is performed in the heating zone of an oven or kiln. A typical class of cathode active materials delivering high energy density contains a high amount of Ni (Ni-rich), for example at least 80 mol-%, referring to the content of non-lithium metals. During application, the particulate cathode active material is exposed to mechanical stress. However, properties such as the mechanical stability still need improvement.

[0010] To a major extent, properties of the precursor translate into properties of the respective electrode active material, such as particle size distribution, content of the respective transition metals and more. It is therefore possible to influence the properties of electrode active materials by steering the properties of the precursor.

[0011] In US 11,305,243, nickel composite hydroxides with a certain surface roughness and an equipment to make them are disclosed.

[0012] It was an objective of the present invention to provide a process by which precursors of cathode active materials with a high mechanical stability can be made. It was further an objective to provide precursors for cathode active materials with a high mechanical stability.

[0013] Accordingly, the process as set out at the outset was found, hereinafter also referred to as inventive process. The inventive process is a process for making a particulate oxyhydroxide or oxide of TM. Said particulate oxyhydroxide or oxide then serves as a precursor for electrode active materials, and it may therefore also be referred to as precursor. The inventive process comprises the following steps (a) and (b) and (c) and (d) and the optional step (e), hereinafter also referred to as step (a) and step (b) and step (d) and step (c) and step (e), or briefly as (a) or (b) or (c) or (d) or (e), respectively. The inventive process will be described in more detail below.

[0014] The resultant (oxy)hydroxide or oxide of TM is in particulate form. The particles size distribution may be determined by light scattering or LASER diffraction or electroacoustic spectroscopy, LASER diffraction being preferred. The particle size distribution may be characterized by the scan, (D90 - D10) divided by D50, D50 being the median value. The span may be in the range of from 0.1 to 2.0. Preferably, the span of the resultant (oxy)hydroxide is below 0.3, more preferably from 0.10 to 0.28, more preferably 0.15 to 0.25.

[0015] In one embodiment of the present invention, the particle shape of the secondary particles of the resultant precursors is spheroidal, that are particles that have a spherical shape. Spherical spheroidal shall include not just those which are exactly spherical but also those particles in which the maximum and minimum diameter of at least 90% (number average) of a representative sample differ by not more than 10%.

[0016] In one embodiment of the present invention, the resultant precursors are comprised of secondary particles that are agglomerates of primary particles. The secondary particles have an outer surface with a roughness in the range of from 1 to 15 nm (Ra) and 5 to 20 nm (Rq) and 10 to 170 nm (Rz). The roughness values are obtained by atomic force microscopy (tapping mode) / 3-dimensional profilometric measurements with image size of 2 x 2 pm. In Scanning Electron Microscopy (“SEM”) imaging, the secondary particles look like having a film on them, and the voids between primary particles look like stuffed with a glue. In preferred embodiments, the crystal contours appear surface finished and polished in SEM imaging, and more preferably, the primary pOarticles cannot be distinguished anymore.

[0017] In one embodiment of the present invention the specific surface (BET) of the resultant precursors is in the range of from 2 to 120 m2 / g, determined by nitrogen adsorption, for example in accordance with to DIN-ISO 9277:2010, after heating to 120°C for one hour.

[0018] The precursor is an (oxy)hydroxide of TM wherein TM comprises Ni and, optionally, at least one transition metal selected from Co and Mn, and, optionally, at least one further metal selected from Ti, Zr, Mo, W, Al, Mg, Nb, Sb, and Ta. Preferably, the precursor comprises nickel and at least one metal selected from Co and Mn, more preferably, said precursor comprise nickel and cobalt and manganese.

[0019] Oxides of TM may contain residual hydroxyl groups or carbonate groups, for example in the range of from 100 to 1,000 ppm (by mass), determined by differential thermogravimetric methods ("DSC”) as weight loss at a temperature in the range of from 180 to 450°C.

[0020] In one embodiment of the present invention, TM is a combination of metals according to general formula (I)

[0021] (NiaCobMnc)i-dMd (I) with a being in the range of from 0.80 to 0.97, preferably from 0.83 to 0.95, b being zero or in the range of from 0.025 to 0.2, preferably from 0.025 to 0.15, c being in the range of from zero to 0.2, preferably from zero to 0.15, or from 0.01 to 0.15, and d being in the range of from zero to 0.1, preferably from zero to 0.05,

[0022] M is selected from Al, Ti, Zr, Mo, W, Al, Mg, Nb, Sb, and Ta, a + b + c = 1.

[0023] Preferably, d = zero.

[0024] In one embodiment of the present invention, TM is a combination of metal according to formula (I a)

[0025] (NiaCobMnc)i.dM1d (I a) wherein a is in the range of from 0.30 to 0.38, b being in the range of from zero to 0.05, and preferably, b is zero, c is in the range of from 0.60 to 0.70, and d is in the range of from zero to 0.05,

[0026] M1is selected from Al, Ti, Zr, W, Mo, Mg, B, and combinations of at least two of the foregoing,

[0027] TM may contain traces of further metal ions, for example traces of ubiquitous metals such as sodium, calcium or zinc, as impurities but such traces will not be taken into account in the description of the present invention. Traces in this context will mean amounts of 0.05 mol-% or less, referring to the total metal content of TM.

[0028] Step (a) includes providing aqueous solution(s) (a) containing water-soluble salts of Ni and of at least one metal selected from Co and Mn and Al, and, optionally, at least one further metal selected from Ti, Zr, Mo, W, Mg, Nb, Sb, and Ta, and an aqueous solution (p) containing an alkali metal hydroxide and, optionally, an aqueous solution (y) containing a complexing agent selected from ammonia, glycine, tartrate, citrate, and oxalate.

[0029] The term "water-soluble salts” refers to salts that exhibit a solubility in distilled water at 25°C of 25 g / l or more, the amount of salt being determined under omission of crystal water and of water stemming from aquo complexes. Water-soluble salts of nickel and cobalt and manganese may preferably be the respective water-soluble salts of Ni2+and Co2+and Mn2+. Examples of water-soluble salts of nickel and cobalt and manganese are the sulfates, the nitrates, the acetates and the halides, especially the chlorides. Preferred are nitrates and sulfates, of which the sulfates are more preferred.

[0030] Said aqueous solution (a) preferably contains Ni and further metal(s) in the relative concentration that is intended as TM of the precursor, or in one of the fractions of the precursor.

[0031] Said aqueous solution (a) preferably contains Ni and, optionally, further metal(s) in a total concentration of from 0.5 to 2.2 mol / l.

[0032] Solution (a1) may have a pH value in the range of from 2 to 5. In embodiments wherein higher pH values are desired, ammonia may be added to solution (a1). In other embodiments, no ammonia is added to solution (a1).

[0033] In step (a), in addition an aqueous solution of alkali metal hydroxide is provided, hereinafter also referred to as solution (p). Examples of alkali metal hydroxides are potassium hydroxide and a combination of sodium and potassium hydroxide, and preferred is sodium hydroxide.

[0034] In embodiments wherein solution (p) contains alkali metal hydroxide, said solution (p) may additionally contain some amount of carbonate, e.g., 0.1 to 2 % by weight, referring to the respective amount of alkali metal hydroxide, added deliberately or by aging of the solution or the respective alkali metal hydroxide. Solution (p) may have a concentration of alkali metal hydroxide in the range from 0.1 to 12 mol / l, preferably 6 to 10 mol / l.

[0035] The pH value of solution (p) is preferably 13 or higher, for example 14.5. In the context of the present invention, pH values are determined at 23°C unless specifically noted otherwise.

[0036] In the inventive process, it is preferred to use ammonia. Solution (y) - if applicable - contains a complexing agent selected from ammonia, glycine, tartrate, citrate, and oxalate. In the context of the present invention, the term glycine includes the compound glycin and its alkali metal salts, for example the potassium or preferably the sodium salt. The terms tartrate and oxalate include the respective free acids and the mono- and dialkali metal salts, for example the mono- or di-potassium salts or the mono- or disodium salts or mixed sodium and potassium salts. The term "citrate” includes citric acid and its alkali metal salts, for example the mono- or di- or trisodium salts and the mono-, di- and tripotassium salts.

[0037] In one embodiment of the present invention, solution (y) has an ammonia concentration in the range of from 1 to 30% by weight.

[0038] In one embodiment of the present invention, solution (y) contains in the range of from 0.05 to 1.0 mol-%, referring to TM, of a complexing agent selected from glycine, tartrate, citrate, and oxalate, or their respective alkali metal salts.

[0039] Step (b) includes combining solution(s) (a) and solution (p) and, if applicable, solution (y), at a pH value in the range of from 9.0 to 13.5, preferably 11 .2 to 12.5, thereby creating particles of a hydroxide of TM. Said particles are slurried in an aqueous medium.

[0040] In one embodiment of the present invention, step (b) is performed at a temperature in the range from 10 to 85°C, preferably at temperatures in the range from 40 to 65°C.

[0041] In one embodiment of the present invention, step (b) is performed at a pressure in the range of from 500 mbar to 10 bar, preferably at ambient pressure.

[0042] In one embodiment of the present invention, an average specific energy of from 8 to 20 W / l, preferably from 9 to 17 W / l is introduced into the slurry, for example with a pitch-blade turbine, preferably with a Rushton turbine or with a combination of a pitch-blade turbine and a Rushton turbine. Stirrers may be one-stage or two-stage or multiple stage, for example three-stage or four-stage, two-stage and three-stage being preferred.

[0043] In one embodiment of step (b), combining solution(s) (a) and solution (p) and, if applicable, solution (y) is performed in a single step. In other embodiments, combining solution(s) (a) and solution (p) and, if applicable, solution (y), are combined in two or more sub-steps, for example in two or three. Said sub-steps may be performed subsequently or n different vessels, for example in different stirred tank reactors, and enable the performance of the precipitation at different pH values or in different concentrations of metals of TM. It is then possible, e.g., to combine solution(s) (a) and solution (p) and, if applicable, solution (y), in a first sub-step at a pH value in the range of from 12.0 to 13.5 and in a second sub-step at a pH value in the range of from 9.0 to 12.5 bus in any way at a pH value lower than in the first sub-step.

[0044] In one embodiment of the present invention, in step (b), mother liquor is withdrawn from the reactors, for example by means of a clarifier, for example a lamellar clarifier, a candle filter or a thickener. Said mother liquor may contain solid particles of precursor, for example from 2 mg / l to 20 g / l, or be free from solid particles for the naked eye.

[0045] In one embodiment of the present invention, step (b) is performed in the presence of seed crystals (5). Seed crystals (5) are (oxy)hydroxides of TM, and they may have the same or a different composition of metals like the hydroxide to be precipitated. Preferably, the composition is similar, for example with a concentration deviation of 10 mol-% or less referring to the composition of TM, to the targeted precursor. For example, in embodiments where a concentration of nickel of 90 mol-% with respect to TM is targeted, seed crystals may have a nickel concentration in the range of from 80 to 100 mol-%.

[0046] Seed crystals may have a diameter in the range of from 1 to 4 m, preferably 2 to 3.8 pm. They are advantageously added as slurry, for example in aqueous Na2SO4 solution.

[0047] By performing step (b), a hydroxide of TM is precipitated in particulate form, and said hydroxide is slurried. That means that solid particles are slurried, namely in the mother liquor.

[0048] After step (b), step (c) is performed. Step (c) includes recovering hydroxide of TM in particulate form through a solid- liquid-separation step, thereby obtaining solid particles of (oxy)hydroxide of TM. Different types of solid-liquid separation methods may be selected, for example decanting, separation by way of a centrifuge, and filtration, filtration being preferred. In a filtration, hydroxide of TM is obtained as filter cake. Suitable apparatuses for filtration are belt filters and filter presses. On laboratory scale, a Buchner filter may be used as well. Supporting operations such as washing the filter cake may be performed as well.

[0049] In one embodiment of step (c), the hydroxide of TM is dried, for example under inert gas or in air or in vacuo, at a temperature in the range of from 60 to 120°C. By drying, especially under air, hydroxide of TM is partially dehydrated and, if applicable, oxidized, and an oxyhydroxide of TM is obtained.

[0050] In step (d), the solid particles from step (c) are mechanically treated in a vessel that bears a vertical stirrer, in the presence or absence of water. A treatment in the presence of water may be performed by mechanically treating the slurry of hydroxide as obtained in step (b), or by mixing the solid particles of (oxy)hydroxide as recovered in step (c) with 5 to 50 % by volume of water. An addition of water may prevent the formation or evolvement of dust. In one embodiment of the present invention, the solid particles from step (c) are pre-dried before commencing step (d), for example to a residual water content in the range of from 1 to 5% by weight.

[0051] By performing step (d), the surface profile of the secondary particles of (oxy)hydroxide of TM is adapted without significantly changing their average particle size. Especially, the surface profile is smoothened. Without significant change means, for example, that a change of less than 1% of the volume-based average particle size is observed, measured by LASER diffraction analysis.

[0052] Mechanical treatment according to step (d) may be characterized by energy input in step (d) by a stirred vessel to be in the range of from 1 W / l to 10 W / l, by peak energy input by pump(s), if applicable, to be in the range of 20 W to 17 kW for circulated amounts of up to 2.5 m3 / h and by peak energy input by mills and mixers, if applicable, to be in the range of 5 kW to 200 kW. Such energy input may be achieved by 60 to 4500 rpm (revolutions per minute). In a special embodiment, the peak energy input of 30 W to 250 kW refers to the shaft power of an impeller pump and corresponds to energy dissipations rate from 2 kW / kg to 7 kW / kg, preferably from 3 to 6 kW / kg.

[0053] In one embodiment of the present invention, the peak energy input by a stirrer in step (d) and in pump(s), if applicable, is in the range of from 20 W to 17 kW for circulated amounts of up to 2.5 m3 / h.

[0054] In one embodiment of the present invention, the vessel in which step (d) is performed is comparable to a pulper. A pulper is known perse and is designed similar to the respective machines that are used to remove soft flesh from agricultural produce, e.g., the soft flesh of coffee beans before fermentation. Preferably, such vessel is charge from the top. Stirring is preferably performed with a vertically installed helix stirrer.

[0055] In another embodiment of the present invention, the vessel in which step (d) is performed is selected from impact mills and classifier mills.

[0056] In one embodiment of the present invention, step (d) is performed in a vessel comparable to a pulper, followed by a mixer, for example a plough share mixer, a ribbon blender or a twin shaft blender.

[0057] In one embodiment of the present invention, step (d) is performed batch-wise. In another embodiment, step (d) is performed continuously.

[0058] In one embodiment of the present invention, step (d) is performed continuously or discontinuously, by a pump selected from dynamic pumps, screw pumps, impeller pumps and displacement pumps, e.g., by conveying and feeding pneumatically or by vibration.

[0059] In one embodiment of the present invention, dust is created in the course of step (d). Such dust may have an average particle diameter (D50) in the range of from 0.1 to 1 pm. Preferably, such dust amounts to up to 0.1 % by weight of the particulate precursor as provided in step (a). The majority of such dust is preferably pressed into any voids between primary particles.

[0060] In one embodiment of the present invention, the duration of step (d) is in the range of from 1 to 120 minutes.

[0061] In one embodiment of the present invention, step (d) is performed in a vessel equipped with a circulation line that is operated by a pump selected from dynamic pumps, screw pumps, impeller pumps and displacement pumps. In this content, a circulation line is a pipe from which slurry is removed from the vessel, mechanically treated with a pump and then returned into the vessel. The flow direction is preferably horizontal with respect to particle withdrawal from the vessel, and it is preferably vertical back into the vessel, if applicable.

[0062] In an - optional - step (e), water is removed by a thermal treatment at a temperature in the range of from 400 to 600°C, before or after step (d). Step (d) is preferably performed in the absence of a lithium compound. By step (e), the precursor is converted into an oxide of TM. Step (e) may be performed in a rotary kiln, in a fluidized bed, or in a roller hearth kiln.

[0063] In one embodiment of the present invention, step (e) is performed under an atmosphere of air, of oxygen-enriched air, or of pure oxygen.

[0064] In one embodiment of the present invention, step (e) has a duration in the range of from 1 hour to 12 hours.

[0065] After step (e), inventive precursors may have a residual moisture content in the range of from 50 to 250 ppm, determined by Karl-Fischer titration.

[0066] Precursors obtained according to the inventive process are excellent starting materials for cathode active materials which are suitable for producing batteries with a high volumetric energy density. They display a high mechanical stability.

[0067] A further aspect of the present invention is related to precursors, hereinafter also referred to as inventive precursors. Inventive precursors are particulate (oxy)hydroxides or oxides of TM with an average particle diameter in the range of from 3 to 20 pm wherein TM is a combination of metals of which at least 94 mol-% are transition metals and TM comprises nickel and at least one metal selected from cobalt and manganese and aluminum, and wherein the particles are agglomerates of primary particles and have an outer surface with a roughness in the range of from 1 to 15 nm (Ra) and 5 to 20 nm (Rq) and 10 to 170 nm (Rz).

[0068] In one embodiment of the present invention, inventive precursors have a specific surface according to BET (hereinafter also "BET -surf ace”) in the range of from 2 to 120 m2 / g. The BET surface may be determined by nitrogen adsorp- tion after outgassing of the sample at 80°C for 30 minutes or more and beyond this accordance with DIN ISO 9277:2010.

[0069] In one embodiment of the present invention, TM is a combination of metals according to general formula (I)

[0070] (NiaCobMnc)i.dMd (I) with a being in the range of from 0.80 to 0.97, preferably from 0.83 to 0.95, b being zero or in the range of from 0.025 to 0.2, preferably from 0.025 to 0.15, c being in the range of from zero to 0.2, preferably from zero to 0.15, or from 0.01 to 0.15, and d being in the range of from zero to 0.1, preferably from zero to 0.05,

[0071] M is selected from Al, Ti, Zr, Mo, W, Al, Mg, Nb, Sb, and Ta, a + b + c = 1.

[0072] In one embodiment of the present invention, TM is a combination of metal according to formula (I a)

[0073] (NiaCobMnc)i-dM1d (I a) wherein a is in the range of from 0.30 to 0.38, b being in the range of from zero to 0.05, and preferably, b is zero, c is in the range of from 0.60 to 0.70, and d is in the range of from zero to 0.05,

[0074] M1is selected from Al, Ti, Zr, W, Mo, Mg, B, and combinations of at least two of the foregoing, a + b + c = 1.

[0075] TM may contain traces of further metal ions, for example traces of ubiquitous metals such as sodium, calcium or zinc, as impurities but such traces will not be taken into account in the description of the present invention. Traces in this context will mean amounts of 0.05 mol-% or less, referring to the total metal content of TM.

[0076] Inventive precursors may contain some carbonate. Carbonate may have been incorporated inadvertently, for example from carbonate of alkali metal hydroxide, or by absorption of CO2 when exposed to air. Inventive precursors may as well contain some counterion from a water-soluble salt that has served as source of, e.g., nickel during the precursor manufacture. Such counterion is preferably sulfate. The amounts of impurities such as carbonate and counter- ion from the source of nickel and further metal(s) preferably does not exceed 1% by weight of the inventive precursors.

[0077] In one embodiment of the present invention, inventive precursor has a span of particle diameter distribution in the range of from 0.1 to 2.0, wherein the span is defined as (D90 - D10) / (D50), preferably below 0.3, more preferably from 0.10 to 0.28, more preferably 0.15 to 0.25.

[0078] Inventive precursors may advantageously made in accordance with the inventive process.

[0079] A further aspect of the present invention relates to the use of inventive precursors for the manufacture of cathode active materials for lithium-ion batteries. A further aspect of the present invention is a process for the manufacture of cathode active materials for lithium-ion batteries comprising the steps of mixing an inventive precursor with a source of lithium and calcining the resultant mixture at a temperature in the range of from 600 to 1000°C, or by calcining an inventive (oxy)hydroxide according in the absence of a lithium compound, mixing the oxide so obtained with a source of lithium and calcining the resultant mixture at a temperature in the range of from 600 to 1000°C, preferably from 700 to 950°C.

[0080] The molar ratio of lithium to TM from inventive precursor may be in the range of from 0.99 : 1 to 1 .2 : 0.8. In embodiments wherein TM corresponds to general formula (I), the molar ratio of lithium to TM is preferably in the range of from 1 : 1 to 1.05 : 1 , more preferably 1 .01 : 1 .00 to 1 .02 : 1.00.

[0081] The present invention is further illustrated by the following working examples and figures.

[0082] Percentages refer to % by weight unless expressly noted otherwise. All pH values were determined at 23°C.

[0083] The following aqueous solutions were used:

[0084] All co-precipitations were performed in a 23-liter stirred tank reactor equipped with four inlets and an overflow system under an atmosphere of N2 that was constantly replenished during step (a). All aqueous solutions were made with de-ionized water. All precipitations were performed under stirring. On regular base, aliquots of the slurries were analyzed for particle diameter.

[0085] I. Manufacture of inventive and comparative precursors

[0086] 1.1 General, step (a)

[0087] Step (a.1): The following aqueous solutions were provided:

[0088] Solution (a.1): NISO4, COSO4 and MnSO4 dissolved in deionized water (molar ratio 91:4.5:4.5, total transition metal concentration: 1.45 mol / kg) Solution (p.1): 25wt% NaOH dissolved in deionized water

[0089] Solution (y.1): 25wt% ammonia in deionized water

[0090] Seed suspension (5.1): Hydroxide of Ni, Co and Mn, molar ratio 91 :4.5:4.5, average particle size 3.9 m, span=1.3, solid content 96 g / l, mother liquor was aqueous Na2SO4 solution (31 wt%)

[0091] Step (b.1): A 10,000 l-stirred tank reactor with baffles and a three-stage pitch-blade turbine (45° angle, diameter^.875 m) was charged with 9500 I deionized water. The stirrer speed was adjusted to 96rpm (-0.42W / L) while the water was heated via the reactor double jacket to 55°C. The temperature was remained constant at 55°C during the complete experiment. As a next step, 660 kg of suspension (5.1) was added. The pH value after addition of all feeds was 11.65. Subsequently, the stirrer speed was adjusted to 210 rpm (-4.4W / L) and feeding solutions (a.1), (p.1 ), and (y.1) were started simultaneously. The stirrer speed was stepwise decreased during the batch synthesis to a final stirrer speed of 96 rpm (-0.55 W / L). The pH value was kept constant at 11.5 by adjusting flow (p.1). The (y.1) flow was adjusted to secure a constant NH3 concentration of 0.5w% in mother liquor. The ratio between reactor volume (10,000 1) and volume flow of total feeds (residence time equivalent) was increased over the run-time resulting in an average residence time equivalent of 5.7 hours. Mother liquor was continuously withdrawn from the suspension resulting in a final solid content of 440 g / L after 25 hours run-time.

[0092] Step (c.1 ): After completion of the batch all feed flows were stopped and the suspension from reactor and clarifier was discharged to a stirred suspension buffer vessel and then filtered using a belt filter. The filter cake was washed twice with solution (p.1).

[0093] Step (d.1):

[0094] The filter cake resulting from step (c.1 ) was re-suspended using de-ionized water in a pulper connected to a circulation flow equipped with a centrifugal pump. The suspension was mechanically treated by operating the pump at 2500 rpm resulting in a circulation flow of 1800 L / h. The peak energy was 15 kW (shaft power), which corresponds to an energy dissipation rate of 5.8 kW / kg. Average residence time in the pulper was 13.5 h. The suspension was then dried in a spray dryer with outlet air temperature of 135°C to obtain the precursor P-CAM.1 with molar composition of Ni:Co:Mn = 91 :4.5:4.5, an average particle size (d50) = 13.9 pm and span = 0.35. The secondary particles have an outer surface with a roughness in the range of from 1 to 15 nm (Ra) and 5 to 20 nm (Rq) and 10 to 170 nm (Rz).

[0095] Step (e.1):

[0096] 180 g of P-CAM.1 was heated in a Linn oven for one hour at 450 °C under flowing air to obtain oxide P-CAM.0.1.

[0097] For comparison purposes, 180 g of precursor resulting from step (c.1 ) was heated in a Linn oven for one hour at 450 °C under flowing air. The metal oxide C-P-CAM.0.2 was obtained as comparative oxide precursor. II. Manufacture of inventive and comparative cathode material

[0098] 11.1 Calcination and post-treatments of inventive precursor

[0099] Calcination and post-treatments of inventive precursor

[0100] 80 g of P-CAM.0.1 was mixed with LiOH monohydrate (molar ratio Li / metal=1.04), 488 mg AI(OH)3 and 406 mg ZrO2. A saggar was charged with the resultant mixture and transferred into a Linn oven. The temperature was raised at rate of 2 C / min to 750 °C under flowing oxygen and then held constant at 750 °C for 8 hours and subsequently allowed to naturally cool under flowing oxygen. The resultant powder was then sieved.

[0101] 80 g powder is then added to 40 ml deionized water stirred for 2 minutes and then immediately filtered on a Buchner funnel to remove water. The wet filter cake is then dried under an N2 atmosphere with reduced pressure at 120 °C for 10 hours.

[0102] The resultant powder is then dry coated with boric acid by mixing 80 g powder, mixing media and 500 mg boric acid for 40 minutes at low speed on a roller mill. A saggar is charged with the dried powder and heat treated in Linn oven. The Linn oven is heated to 300 °C for 2 hours under oxygen atmosphere and allowed to cool naturally. The resultant powder was then sieved.

[0103] After sieving the powder had an average particle diameter (D50) of 16 pm and a span of 0.3. Inventive CAM.1 is obtained.

[0104] II.2 Calcination and post-treatments of a comparative precursor

[0105] Analogous treatment of C-P-CAM.0.2 results in C-CAM.2.

[0106] III. Testing of Cathode Active Material

[0107] 111.1 Cathode manufacture

[0108] Positive electrode: PVDF binder (polyvinylidene difluoride, Solef® 5130) was dissolved in NMP (Merck) to produce a 7.5 wt.% solution. For electrode preparation, binder solution (2.5 wt.%), and carbon black (Li 400, 2.5 wt.-%) were suspended in NMP. After mixing using a planetary centrifugal mixer (ARE-250, Thinky Corp., Japan), either inventive CAM.2 or C-CAM.1 (95 wt.%) was added and the suspension was stirred again to obtain a lump-free slurry. The solids content of the slurry was adjusted to 65%. The slurry was coated onto Al foil using a KTF-S roll-to-roll coater (Mathis AG). Prior to use, all electrodes were calendared. The thickness of cathode material was 85 m, corresponding to 21 mg / cm2. All electrodes were dried at 120°C for 7 hours before battery assembly. III.2 Electrolyte Manufacture

[0109] A base electrolyte composition was prepared containing 12.0 wt% of LIPFe, 44.0 wt% of ethylene carbonate (EC), and 44.0 wt% of di-ethyl I carbonate (DMC) (EL base 1), based on the total weight of EL base 1.

[0110] 111.3 Coin Cell Manufacture

[0111] Coin-type half cells (20 mm in diameter and 3.2 mm in thickness) comprising a cathode prepared as described under 11.1.1 and lithium metal as working and counter electrode, respectively, were assembled and sealed in an Ar-filled glove box. In addition, the cathode and anode and a separator were superposed in order of cathode II separator II Li foil to produce a half coin cell. Thereafter, 0.095 mL of the EL base 1 which is described above (III.2) were introduced into the coin cell.

[0112] 111.4 Cycling Tests

[0113] The initial performance, C-rate performance and cycling performance were measured as follows: Coin half cells according to II.3 were tested in a voltage range between 4.3 V to 2.7 V at room temperature. For the initial cycles, the initial lithiation was conducted in the CC-CV mode, i.e., a constant current (CC) of 0.04 C was applied until reaching 4.3V, followed by the CV step until the current dropped to 0.01 C. After 10 min resting time, reductive lithiation was carried out at constant current of 0.04 C up to 27 V. For the C-rate test charge and discharge rates were adjusted accordingly. For the cycling test, the constant current was chosen to be 0.33 C until 56 cycles were reached.

[0114] After 56 cycles tested against a graphite anode, cells containing cathodes based on CAM.1 shows superior properties compared to C-CAM.2.

Claims

Patent Claims1. Process for making a particulate (oxy)hydroxide or oxide of TM, wherein TM is a combination of metals of which at least 94 mol-% are transition metals and TM comprises nickel and at least one metal selected from cobalt and manganese and aluminum, wherein said process comprises the steps of:(a) providing aqueous solution(s) (a) containing a water-soluble salt of nickel and at least one metal selected from cobalt and manganese and aluminum, and an aqueous solution (p) containing an alkali hydroxide and, optionally, an aqueous solution (y) containing a complexing agent selected from ammonia, glycine, tartrate, citrate, and oxalate,(b) combining solution(s) (a) and solution (p) and, if applicable, solution (y), at a pH value in the range of from 9.0 to 13.5 in one or more sub-steps, thereby precipitating a hydroxide of TM in particulate form,(c) recovering hydroxide of TM in particulate form through a solid-liquid-separation step,(d) mechanically treating the solid particles of hydroxide of TM or the respective oxide or oxyhydroxide with a peak energy input in the range of from 30 W to 250 kW, thereby adapting the surface profile without significantly changing the average particle size,(e) and, optionally, removing water by a thermal treatment at a temperature in the range of from 400 to 600°C, before or after step (d).

2. Process according to claim 1 wherein step (d) is performed in a vessel with a vertical stirrer.

3. Process according to claim 1 or 2 wherein the particulate (oxy)hydroxide is selected from hydroxides, oxyhydroxides and oxides of TM wherein TM is a combination of metals according to general formula (I)(NiaCobMnc)i-dMd (I) with a being in the range of from 0.80 to 0.97, b being zero or in the range of from 0.025 to 0.2, c being in the range of from zero to 0.2, and d being in the range of from zero to 0.1 ,M is selected from Mg, Al, Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, a + b + c = 1 , and b + c > zero.

4. Process according to any of the preceding claims wherein the energy input in step (d) is measured as shaft power5. Process according to any of the preceding claims wherein step (d) is performed in the presence of water and a solids content in the range of from 30 to 65 % by weight.

6. Process according to any of the preceding claims wherein dust is generated in step (d).

7. Process according to any of the preceding claims wherein step (d) is performed in a vessel equipped with a circulation line that is operated by a pump selected from dynamic pumps, screw pumps, impeller pumps and displacement pumps.

8. Process according to claim 7 wherein the peak energy input by the stirrer in step (d) and in pump(s), if applicable, are in the range of from 20 W to 17 kW for circulated amounts of up to 2.5 m3 / h.

9. Process according to any of the preceding claims wherein step (b) is performed in the presence of seed crystals (5).

10. Particulate (oxy)hydroxide or oxide of TM with an average particle diameter in the range of from 3 to 20 pm wherein TM is a combination of metals of which at least 94 mol-% are transition metals and TM comprises nickel and at least one metal selected from cobalt and manganese and aluminum, and wherein the particles are agglomerates of primary particles and have an outer surface with a roughness in the range of from 1 to 15 nm (Ra) and 5 to 20 nm (Rq) and 10 to 170 nm (Rz).11 . Particulate (ox)hydroxide according to claim 10 having a specific surface according to BET in the range of from 2 to 120 m2 / g.

12. Particulate (ox)hydroxide according to claim 10 or 11 wherein the particulate (oxy)hydroxide is selected from hydroxides, oxyhydroxides and oxides of TM wherein TM is a combination of metals according to general formula (I)(NiaCobMnc)i.dMd (I) with a being in the range of from 0.80 to 0.97, b being zero or in the range of from 0.025 to 0.2, c being in the range of from zero to 0.2, and d being in the range of from zero to 0.1,M is selected from Mg, Al, Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, a + b +c = 1, and b +c > zero.

13. Particulate (ox)hydroxide according to any of claims 10 to 12 wherein such (oxy)hydroxide has a span of particle diameter distribution in the range of from 0.1 to 2.0, and wherein the span is defined as (D90 - D10) / (D50).

14. Use of particulate (ox)hydroxides according to any of claims 10 to 13 for the manufacture of cathode active materials for lithium-ion batteries.

15. Process for the manufacture of cathode active materials for lithium-ion batteries comprising the steps of mixing a particulate (oxy)hydroxide to any of the claims 10 to 13 with a source of lithium and calcining the result- ant mixture at a temperature in the range of from 600 to 1000°C, or by calcining a particulate (oxy)hydroxide according to any of the claims 7 to 10 in the absence of a lithium compound, mixing the oxide so obtained with a source of lithium and calcining the resultant mixture at a temperature in the range of from 600 to 1000°C.

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