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Title:
PROCESS FOR MAKING A COATED OXIDE MATERIAL, AND VESSEL COMBINATION SUITABLE FOR SUCH PROCESS
Document Type and Number:
WIPO Patent Application WO/2018/099754
Kind Code:
A1
Abstract:
Process for making a coated oxide material, said process comprising the following steps: (a)providing a lithiated transition metal oxide slurried in an aqueous solution that contains a cobalt salt selected from cobalt nitrate and cobalt acetate and a lithium salt selected from lithium acetate and lithium nitrate,said lithiated transition metal oxide containing at least one transition metal other than cobalt, (b)removing water in one or more steps in order to provide a solid, (c)calcining the solid obtained in (b) at a temperature in the range of from 500 to 750°C, (d)cooling down the material resulting from step (c), wherein step (c) is performed in an open vessel (A) selected from saggers, crucibles, pans, and open cups made from a ceramic matrix composite that is placed into a sagger or crucible or pan or open cup (B) and wherein open vessel (A) is reversibly attached to such sagger or crucible or pan or open cup (B).

Inventors:
KALO, Benedikt (Carl-Bosch-Strasse 38, Ludwigshafen, 67056, DE)
LAMPERT, Jordan (23800 Mercantile Road, Beachwood, Ohio, 44122, US)
Application Number:
EP2017/079795
Publication Date:
June 07, 2018
Filing Date:
November 20, 2017
Export Citation:
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Assignee:
BASF SE (Carl-Bosch-Strasse 38, Ludwigshafen am Rhein, 67056, DE)
International Classes:
B65D21/00; B65D77/04; C01G51/00; C01G53/02; F27B14/10; H01M4/131; H01M4/1391; H01M4/525; H01M10/0525
Foreign References:
JP2012068017A2012-04-05
US20140154437A12014-06-05
CN106025254A2016-10-12
CN105731549A2016-07-06
US7381496B22008-06-03
Attorney, Agent or Firm:
BASF IP ASSOCIATION (BASF SE, G-FLP - C006, Ludwigshafen, 67056, DE)
Download PDF:
Claims:
Claims

Process for making a coated oxide material, said process comprising the following steps:

(a) providing a lithiated transition metal oxide slurried in an aqueous solution that contains a cobalt salt selected from cobalt nitrate and cobalt acetate and a lithium salt se lected from lithium acetate and lithium nitrate, said lithiated transition metal oxide con taining at least one transition metal other than cobalt,

(b) removing water in one or more steps in order to provide a solid,

(c) calcining the solid obtained in (b) at a temperature in the range of from 500 to 750°C,

(d) cooling down the material resulting from step (c), wherein step (c) is performed in an open vessel (A) selected from saggers, crucibles, pans, and open cups made from a ceramic matrix composite that is placed into a sagger or crucible or pan or open cup (B) and wherein open vessel (A) is reversibly attached to such sagger or crucible or pan or open cup (B).

Process according to claim 1 wherein the calcining step (c) is carried out in an oven selected from roller hearth kilns, shuttle kilns, box furnaces, and tunnel kilns.

Process according to claim 1 or 2 wherein the cooling step (d) or a heating phase in step (b) is performed at a rate in the range of from 1 to 50°C/min.

Process according to any of the preceding claims wherein the wall thickness of component (A) is in the range of from 0.1 to 2 mm.

Process according to any of the preceding claims wherein lithiated transition metal oxide in step (a) is selected from materials of general formula (I)

Li(i+x)[NiaCObMncMd](i-x)02 (I) wherein

M is selected from Ca, Mg and Ba, zero < x < 0.2

0.7 < a < 1 - d

zero < b < 0.3

zero < c < 0.3

0.01 < d < 0.05 and a + b + c + d = 1.

Vessel combination selected from combinations of two open vessels, from which

(A) Is selected from saggers, crucibles, pans, and open cups made from ceramic matrix composite, and

(B) is selected from saggers, crucibles, pans, and open cups, and wherein component (A) is placed into component (B), and wherein component (A) is reversibly attached to component (B).

Vessel combination according to claim 6 wherein the wall thickness of component (A) is in the range of from 0.1 to 2 mm.

Vessel combination according to claim 6 or 7 wherein the ceramic matrix composite comprises fibers from aluminum oxide or mullite or combinations thereof and a ceramic selected from aluminum oxide, zirconia, magnesium oxide, quartz, mullite, cordierite and combinations of at least two of the foregoing.

Vessel combination according to any of claims 6 to 8 wherein component (A) has a square-shaped or circular base.

Vessel combination according to any of claims 6 to 9 wherein component (B) is made from a material selected from stainless steel, nickel base alloy and ceramic.

Vessel combination according to any of claims 6 to 10 wherein component (B) is made from a ceramic selected from alumina, silicon carbide, mullite, cordierite, spinel, and from combinations of at least two of the foregoing.

Description:
Process for making a coated oxide material, and vessel combination suitable for such process

The present invention is directed towards a process for making a coated oxide material, said process comprising the following steps:

(a) providing a lithiated transition metal oxide slurried in an aqueous solution that contains a cobalt salt selected from cobalt nitrate and cobalt acetate and a lithium salt selected from lithium acetate and lithium nitrate, said lithiated transition metal oxide containing at least one transition metal other than cobalt,

(b) removing water in one or more steps in order to provide a solid,

(c) calcining the solid obtained in (b) at a temperature in the range of from 500 to 750°C, (d) cooling down the material resulting from step (c), wherein step (c) is performed in an open vessel (A) selected from saggers, crucibles, pans, and open cups made from a ceramic matrix composite that is placed into a sagger or crucible or pan or open cup (B) and wherein open vessel (A) is reversibly attached to such sagger or crucible or pan or open cup (B).

Lithiated transition metal oxides are currently being used as cathode active materials for lithium- ion batteries. Extensive research and developmental work has been performed in the past years to improve properties like charge density, 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 work has been spent to improve manufacturing methods.

In a usual process for making cathode materials for lithium-ion batteries, first a so-called pre- cursor is being formed by co-precipitating the transition metals as carbonates, oxides or preferably as hydroxides that may or may not be basic. The precursor is then mixed with a lithium salt such as, but not limited to LiOH, U2O, L1NO3 or - especially - U2CO3 - and calcined (fired) at high temperatures. Lithium salt(s) can be employed as hydrate(s) or in dehydrated form. The calcination - or firing - generally also being referred to as thermal treatment of the precursor is usually carried out at temperatures in the range of from 600 to 1 ,000 °C. During the thermal treatment a solid state reaction takes place, and the cathode active material is formed. The thermal treatment may be performed in the heating zone of an oven or kiln. Two general types of achieving the transportation of the precursor into the heating zone - and removal of the cathode active material from the heating zone - are most widely used. One type is to move a stream of powder through the heating zone, for example in a rotary kiln. Rotary kilns have the challenge, though, that the strongly corrosive precursor or a strongly corrosive coating material may damage the kiln material and thereby also cause impurity of the manufactured product.

Several modern processes apply one or more coating steps that require additional thermal treatment. For example, in US 7,381 ,496 a process is described wherein a Ni-based cathode active material is coated with UC0O2, followed by heat treatment. Special attention is needed for selecting the material of the vessel in which the thermal treatment of the coated cathode active material is performed because the coating material is rather corrosive. The corrosion may cause a degradation of the material of the vessel in which the cathode material is thermally treated, leading to an undesired contamination of the cathode active material with vessel material and to a short life time of the containers. Rotary kilns, on the other hand, suffer even more from degradation due to a combination of chemical corrosion and mechanical abrasion. In addition, rotary kilns are quite disadvantageous for multi-product facilities where cross contamination may be of concern.

It was therefore an objective to provide a method for making oxide materials that can be utilized in contact with corrosive materials and allows for higher conversions in a given heating process. It was further an objective to provide the necessary equipment for such process.

Accordingly, the process defined at the outset has been found, hereinafter also referred to as inventive process or process according to the (present) invention. In addition, the open vessel combinations defined at the outset have been found, hereinafter also referred to as inventive vessel combinations or vessel combinations according to the present invention. Inventive vessel combinations will be defined in more details below.

The inventive process comprises several steps, hereinafter also referred to as step (a), step (b), step (c) and step (d), respectively. Said steps are

(a) providing a lithiated transition metal oxide slurried in an aqueous solution that contains a cobalt salt selected from cobalt nitrate and cobalt acetate and a lithium salt selected from lithium acetate and lithium nitrate, said lithiated transition metal oxide containing at least one transition metal other than cobalt,

(b) removing water in one or more steps in order to provide a solid,

(c) calcining the solid obtained in (b) at a temperature in the range of from 500 to 750°C,

(d) cooling down the material resulting from step (c), wherein step (c) is performed in an open vessel (A) selected from saggers, crucibles, pans, and open cups made from a ceramic matrix composite that is placed into a sagger or crucible or pan or open cup (B) and wherein open vessel (A) is reversibly attached to such sagger or crucible or pan or open cup (B).

Examples of lithiated transition metal oxides provided in step (a) are layered lithium transition metal oxides that contain at least one transition metal other than cobalt, that means, at least five mole percent of the transition metal portion is a transition metal other than cobalt. Suitable are, for example, manganese or nickel or a combination of manganese and nickel, or a combination of manganese and cobalt, or a combination of nickel and cobalt, or a combination of nickel, cobalt and manganese.

Further examples are a lithiated nickel-cobalt aluminum oxide ("NCA"). Particularly preferred lithiated transition metal oxides are so-called doped lithiated transition metal oxides. In the context of the present invention, doped lithiated transition metal oxides are those that contain 0.1 to 3 mole-% of a metal other than transition metals, for example, an alkaline earth metal, in the transition metal layer. Said doping element - or said doping elements - are not present as a coating but rather dispersed throughout the particles of lithiated transition metal oxide, either homogeneously or at least enriched in some regions of particles of lithiated transition metal oxide.

In one embodiment of the present invention, in step (a) a slurry of an NCA is provided, prefera- bly a material according to the general formula Li(i +g )[NihCOiAlj](i- g )02. Typical values for g, h, i, and j are: g from 0.0 to 0.1 , h from 0.80 to 0.90, i from 0.15 to 0.20, and j from 0.01 to 0.05.

In a preferred embodiment of the present invention, in step (a) a slurry of a lithiated transition metal oxide of general formula (I) is provided,

Li(i + x)[NiaCObMn c Md](i-x)02 (I) wherein M is selected from Ca, Mg and Ba, zero < x < 0.2

0.7 < a < 1 - d

zero < b < 0.3 - d

zero < c < 0.3 - d

0.01 < d < 0.05 and a + b + c + d = 1.

Particularly preferred is a slurry of

Li(i + x)[Ni a Mgd](i-x)02 (I a) wherein zero < x < 0.05

0.8 < a < 1 - d 0.01 < d < 0.05 and a + b + d = 1.

In a special embodiment of the present invention, lithiated transition metal oxides slurried in step (a) are selected from layered nickel-cobalt-magnesium oxides and layered nickel- magnesium oxides, in any case doped or non-doped, for example Lii.o3(Nio.9Coo.o9Mgo.oi)o.9702, Lii.o3(Nio.94Coo.o5Mg 0 .oi )o.9702, and Lii.o5(Mg 0 .o25N 10.975)0.9502.

In a special embodiment, in step (a) a slurry of at least two different lithiated transition metal oxides is provided. In one embodiment of the present invention, lithiated transition metal oxide has an average particle diameter (D50) in the range of from 1 to 20 μηη, preferably 3 to 15 μηη.

Slurries according to step (a) are aqueous slurries. Aqueous slurries according to the present invention are selected from slurries that contain up to 20 % by volume of organic solvent, for example ethanol or isopropanol or ethylene glycol, said percentage referring to the entire continuous phase, or they do not contain any organic solvent. Preferably, aqueous slurries in the context of the present invention do not contain any organic solvent.

Slurries according to step (a) may have a water content in the range of from 10% of up to 85% by weight. Thick slurries with a water content in the range of from 10 to 30% by weight are preferred.

Lithiated transition metal oxide is slurried in an aqueous solution that contains a cobalt salt selected from cobalt nitrate and cobalt acetate and a lithium salt selected from lithium acetate and lithium nitrate.

In one embodiment of the present invention, lithiated transition metal oxide is slurried in an aqueous solution that contains cobalt nitrate, Co(NOs)2, and lithium nitrate, L1NO3. Preferably, the molar ratio of cobalt nitrate and lithium nitrate is in the range of from 9:10 to 10:9, more preferably, from 99:100 to 100:99.

In one embodiment of the present invention, lithiated transition metal oxide is slurried in an aqueous solution that contains cobalt acetate, Co(OAc)2, and lithium acetate, LiOAc. Preferably, the molar ratio of cobalt acetate and lithium acetate is in the range of from 9:10 to 10:9, more preferably, from 99:100 to 100:99. In one embodiment of the present invention, the aqueous solution containing Co(NOs)2 and L1NO3 or the respective acetates, respectively, additionally contains a nitrate or acetate of at least one trivalent metal other than Co, for example Fe(N0 3 )3, AI(N0 3 )3, Mn(N0 3 )3, V(N0 3 )3, Fe(OAc)3, AI(OAc)3, Mn(OAc)3, V(OAc)3 The molar percentage of said additional metal is in the range of from 1 to 20 % of Co. Preferred nitrate of trivalent metal other than Co(NOs)2 is

AI(N0 3 ) 3 .

The molar amount of L1NO3 to Co(NOs)2 plus, if applicable, nitrate of trivalent metal is preferably in the range of 9:10 to 10:9, more preferably, from 99:101 to 105:95.

The molar amount of LiOAc to Co(OAc)2 plus, if applicable, acetate of trivalent metal is preferably in the range of 9:10 to 10:9, more preferably, from 99:101 to 105:95.

The solution in which such lithiated transition metal oxide is slurried has preferably as high a concentration of the nitrates - or acetates, if applicable - as possible. For example, the concentration of nitrates may be in the range of from 50 % by weight of nitrates up to 80% in case the solubility of the respective nitrate provides so. Many nitrates may be provided as hydrate or as aquo complexes. In determining the weight, hydrate water and water ligands are neglected. In the case of acetates, the same is applicable mutatis mutandis.

Slurrying may be performed, for example, at ambient temperature or at a temperature in the range of from zero to 20°C, or, at a temperature above ambient temperature, for example 25 to 50°C. Slurrying is usually done by applying one or more mixing operations, for example, shaking or stirring.

In step (b), water is removed in one or more steps, for example, in two or three or four steps. The removal of water may be performed by evaporation, for example at 105 to 200° at normal pressure, or under reduced pressure, for example at a temperature in the range of from 50 to 150°C. In a special embodiment, water is removed with the help of a filter press.

As a result of step (b), a solid is obtained. Said solid may have a residual moisture, for example, in the range of from 100 ppm to 1000 ppm, ppm being ppm by weight. Residual moisture is de- fined as water that remains in said solid at up to 150 or even 200°C but may be removed at temperatures above 200°C.

In an optional step, the solid is screened using a vibrated screen with 32 μηη mesh size. Lumps may be disposed of, the fine fraction is the desired product for use in step (c). The product fraction typically is more than 99 % of the solid. In step (c), the solid obtained in step (b) is calcined at a temperature in the range of from 500 to 750°C. Said calcination may be performed at constant temperature or with a temperature profile. Preferably, step (c) is performed without stirring. Although it is possible to perform step (c) in a pendulum kiln it is preferred to use an oven selected from roller hearth kilns, shuttle kilns, box furnaces, and tunnel kilns.

In a preferred embodiment, the heating rate for performing step (c) is in the range of from 1 to 50 °C/min, preferably 1 to 5°C/min.

In one embodiment of the present invention, step (c) is performed over a time of 1 to 48 hours, preferably 2 to 24 hours and more preferably 2 to 5 hours. In the course of step (c), water and NO x is evolved, for example NO2. It is preferred to apply a means for denitrification of the off-gas of step (c).

Step (c) is performed in an open vessel (A) selected from saggers, crucibles, pans, and open cups made from a ceramic matrix composite that is placed into a sagger or crucible or pan or open cup (B) and wherein open vessel (A) is reversibly attached to such sagger or crucible or pan or open cup (B). Such combination of open vessel (A) and sagger or crucible or pan or open cup (B) is hereinafter also referred to as inventive vessel combination.

In a preferred embodiment of the present invention, neither sagger or crucible or pan or open cup (A) nor sagger or crucible or pan or open cup (B) have a lid.

In some embodiments inventive vessel combinations have one or more handles, but preferably they do not. In the context of the present invention, open vessel (A) is sometimes also referred to as component (A), and sagger or crucible or pan or open cup (B) are sometimes also referred to as component (B).

Component (A) is reversibly attached to component (B), and preferably, component (A) is not form-fitted in component (B), neither at ambient temperature nor at the highest temperature of step (c). Thus, when at ambient temperature, component (A) can be removed easily from component (B), for example, manually. In the context of the present invention, "reversibly attached" means that components (A) and (B) are can be disassembled without damaging either one of components (A) or (B). It is possible to keep component (A) in position with component (B) us- ing a fastening means such as, but not limited to one or more bolts or clips. Open vessel (A) is the vessel into which the solid according to step (b) is transferred. Open vessels (A) that are pans or open cups have a circular base, and they are better distinguished by the dimensions. In pans, the walls are up to 25% of the diameter of the base, for example 5 to 25%, and in open cups, the walls are from 26 to 300% of the diameter of the base.

Open vessels (A) comprise of a ceramic matrix composite. Said ceramic matrix composite contains ceramic fibers, and it additionally comprises a ceramic particulate material, also referred to as ceramic matrix. Ceramic fibers and ceramic matrix may have identical or different composition.

Ceramic fibers and ceramic particulate materials may each be selected from oxide and non- oxide ceramics. Examples of non-oxide ceramics are carbides and borides and nitrides and oxynitrides. Particular examples of non-oxide ceramics are silicon carbide, silicon boride, silicon nitride, silicon oxynitride, silicon boron nitride, hereinafter also referred to as SiBN, silicon car- bon nitride, hereinafter also referred to as SiCN, and in particular combinations from SiC and S13N4. Preferred are oxide ceramics, hereinafter also referred to as oxide-based ceramics. Oxide ceramics are oxides of at least one element selected from Be, Mg, Ca, Sr, Ba, rare earth metals, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Zn, B, Al, Ga, Si, Ge, Sn, Re, Ru, Os, Ir, In, Y, and mixtures of at least two of the foregoing. Oxide-based ceramics may be selected from doped ceramics, wherein one main component is doped with up to 1 molar % components other than the main component, and from enforced ceramics, wherein one component is the main component, for example at least 50 molar %, and one or more further components - reinforcing components - are present in ranges from 1.1 to 25 molar %. Further examples are titanates and silicates.

Preferred example of titanates is aluminum titanate. Preferred example of silicates is magnesium silicate.

Examples of enforced ceramics are reinforced alumina and reinforced zirconia. They may con- tain two or more different reinforcement oxides and may thus be referred to as binary or ternary mixtures. The following binary and ternary mixtures are preferred: aluminum oxide enforced with 1 .1 to 25% by weight of one of the following: cerium oxide Ce02, ytterbium oxide Yb203, magnesia MgO, calcium oxide CaO, scandium oxide SC2O3, zirconia Zr02, yttrium oxide Y2O3, boron oxide B2O3, combinations from SiC and AI2O3, or aluminum titanate. More preferred reinforcing components are B2O3, Zr02 and Y2O3.

Preferred zirconia-reinforced alumina is AI2O3 with from 10 to 20 mole-% Zr02. Preferred examples of reinforced zirconia are selected from Zr02 enforced with from 10 to 20 mole-% CaO, in particular 16 mole-%, from 10 to 20 mole-% MgO, preferably 16 mole-%, or from 5 to 10 mole-% Y2O3, preferably 8 mole-%, or from 1 to 5 mole-% Y2O3, preferably 4 mole-%. An example of a preferred ternary mixture is 80 mole-% AI2O3, 18.4 mole-% Zr02 and 1 .6 mole-% Y2O3. Preferred fiber materials are oxide ceramic materials, carbide ceramic materials, nitride ceramic materials, carbon fibers, SiBCN fibers, basalt, boron nitride, tungsten carbide, aluminum nitride, titania, barium titanate, lead zirconate-titanate and boron carbide. Even more preferred fiber materials are AI2O3, mullite, SiC, Zr02 and carbon fibers.

In one embodiment of the present invention component (A) comprises fibers from silicon carbide, silicon nitride, silicon oxynitride, carbon fiber or combinations thereof and a ceramic matrix selected from SiC, silicon nitride, silicon oxynitride, aluminum oxide, silica, mullite, cordierite, spinel and combinations of at least two of the foregoing.

In one embodiment of the present invention the fibers are made from aluminum oxide, and the ceramic matrix composite comprises a ceramic particulate material selected from aluminum oxide, silicate, mullite, spinel, cordierite and combinations of at least two of the foregoing. Preferred is aluminum oxide.

Preferred are creep resistant fibers. In the context of the present invention, creep resistant fibers are fibers that exhibit minimum - or no - permanent elongation or other permanent deformation at temperatures up to 1 ,400°C In one embodiment of the present invention, ceramic fibers may have a diameter in the range of from 7 to 12 μηη. Their length may be in the range of from 1 mm up to 1 km or even longer, so- called endless fibers. In one embodiment, several fibers are combined with each other to yarns, textile strips, hoses, or the like. In a preferred embodiment ceramic fibers used in the present invention have a tensile strength of at least 50 MPa, preferably at least 70 MPa, more preferably at least 100 MPa, and even more preferably at least 120 MPa. A maximum value of the tensile strength of ceramic fibers used in the present invention is 3,100 MPa or even 10,000 MPa. The tensile strength may be determined with a tensile tester. Typical measuring conditions are cross-head speeds of 1 .2 to 1.3 cm/min, for example 1 .27 cm/min, and 7.61 cm gauge. In one embodiment of the present invention, the matrix is made from an oxide ceramic material or a carbide. Preferred oxide ceramic materials for the matrix are AI2O3, mullite, SiC, ZrC"2 and spinel, MgAI 2 0 4 .

Particularly preferred components are SiC/SiC, C/SiC, Zr0 2 /Zr0 2 , Zr0 2 /Al 2 0 3 , Al 2 0 3 /Zr0 2 , AI2O3/AI2O3 and mullite/mullite. The fiber material is in each foregoing case the first and the matrix the second material.

In one embodiment of the present invention, component (A) comprises 20 to 60 % by volume ceramic fiber.

Component (A) is porous. In many cases, it consists of 50 to 80% ceramic matrix composite in total, the rest is gas, for example air (porosity). In one embodiment of the present invention, component (A) has a porosity in the range of from 20 % to 50 %; thus, component (A) is not gas tight in the sense of DIN 623-2. In one embodiment of the present invention, component (A) comprises fibers from aluminum oxide and a ceramic selected from aluminum oxide, quartz, mullite, cordierite and combinations of at least two of the foregoing, for example aluminum oxide and mullite or aluminum oxide and cordierite. Even more preferably, the ceramic matrix composite (A) comprises fibers from aluminum oxide and aluminum oxide ceramic.

In one embodiment of the present invention, the inner surface of component (A) appears smooth to the naked eye. In other embodiments, the inner surface of component (A) exhibits a certain roughness. Roughness in this context refers to a peak to valley height difference of up to 3 mm.

Component (B) is selected from metals and alloys and ceramic materials. Useful metals are tungsten, molybdenum, iron, nickel, and titanium. Useful alloys are steels, nickel-based alloys and cobalt refractory alloys. In a preferred embodiment, component (B) is made from steel, for example 300 series stainless steels, 304, 309 and 316. Examples of suitable steels are 1 .46xx, 1 .47xx and 1 .48xx, cobalt-based allows such as Haynes 25, and nickel-based alloys of grade 2.48xx, in particular grade 1.48xx grades, 2.4856 and 2.4851. A further example of useful alloy is molybdenum titanium zirconium, in brief TZM.

In one embodiment of the present invention, component (B) is made from an alloy with a ther- mal conductivity in the range of from 15 to 35 W/mK at 1000°C.

In one embodiment of the present invention, component (B) is made from ceramic. Examples of ceramics are aluminum oxide, quartz, mullite, magnesium oxide, cordierite and combinations of at least two of the foregoing.

In one embodiment of the present invention, component (A) of inventive vessels has an average wall thickness in the range of from 0.1 to 2 mm, preferably from 0.2 to 1 mm. The base of component (A) in embodiments in which component (A) has a flat base, it may be of the same thickness or thicker or thinner, for example up to 10 mm, preferably 2 to 5 mm.

In embodiments wherein component (B) is made from an alloy, the wall thickness preferably is 1 to 5 mm, more preferably 1.5 to 3 mm. The base in this case preferably is of the same wall thickness as the walls are. In embodiments wherein component (B) is made from ceramic, the wall thickness preferably is in the range of from 4 mm to 15 mm, more preferably from 7 mm to 13 mm. The base in this case preferably is of the same thickness or thicker than the outside walls, for example 10 to 20 mm, preferably 12 to 18 mm.

In one embodiment of the present invention, in component (A) the angle between each wall and the basis is 90°. In a preferred embodiment, component (A) has inclined walls, and the angle between each wall and the basis is in the range of from 91 to 100°.

In a preferred embodiment of the present invention, inventive vessels may contain 100 ml up to 25 I of particulate material, preferred are 2 I to 20 I, and even more preferred are 3 to 15 I.

Smaller vessels according to the present invention are possible, but they are economically disadvantageous. In state-of-the-art vessels the heat transfer may be disadvantageous in a way that the residence time in heating and/or cooling zones is unfavorably long or in way that pronounced temperature profiles in the powder to be thermally treated are observed that are in disfavor of a homogeneous product. If heat treatment is performed in inventive vessels, heat transfer is facilitated and accelerated. That leads to improved homogeneity of the heat-treated material.

Inventive vessels are advantageous for any solid state reaction to make oxide materials from a precursor in a solid state reaction. By using inventive vessels the shortcomings of the known processes discussed at the outset may readily be overcome. Exchange of product without cross contamination is easy, and heating and cooling before and after the thermal treatment may be performed at much faster a rate than with vessels known, if component (B) is made of an alloy. The inventive vessel combination is advantageous compared to known vessels as the inlay, component (A), can be exchanged easily when corroded or otherwise damaged or undesired to reuse, while component (B) can be kept using.

The shapes of components (A) and (B) may be the same or different, preferably they are different. Component (B) may have a base that is circular or ellipsoid or polygonal, for example rectangular or quadrangular. Preferred are rectangular and in particular quadrangular-base inventive vessels, for example rectangular and in particular square base vessels. Specific embodiments of quadrangular-base inventive vessels are those with rounded angles and especially inventive vessels with a square base with rounded angles.

In step (d), the material obtained in step (c) is cooled down, for example by quenching or slowly. It is preferred to use a cooling rate in the range of from 1 to 50°C/min, preferably 2 to 10 °C/min.

In many embodiments, step (d) is stopped when the product obtained from step (d) has ambient temperature or a few °C more than ambient temperature, for example up to 100°C. The inventive process may include one or more optional steps, for example a sieving step or a de-agglomeration step.

By performing the inventive process, the desired coated cathode active materials may be made conveniently and with particularly low contamination with material from component (A).

A further aspect of the present invention relates to a combination of vessels, in the context of the present invention also referred to as inventive vessel combination. Inventive vessel combinations are selected from combinations of two open vessels, from which

(A) component (A) is selected from saggers, crucibles, pans, and open cups made from ceramic matrix composite, and

(B) component (B) is selected from saggers, crucibles, pans, and open cups, and wherein component (A) is placed into component (B), and wherein component (A) is revers- ibly attached to component (B).

In a preferred embodiment of the present invention, the wall thickness of component (A) is in the range of from 0.1 to 2 mm, more preferably from 0.2 to 1 mm. The base of component (A) in embodiments in which component (A) has a flat base, it may be of the same thickness or thicker or thinner, for example up to 10 mm, preferably 2 to 5 mm.

In a preferred embodiment of the present invention the ceramic matrix composite comprises of fibers from aluminum oxide, zirconia, or mullite or combinations thereof and a ceramic selected from aluminum oxide, quartz, mullite, magnesium oxide cordierite and combinations of at least two of the foregoing.

In a preferred embodiment of the present invention component (A) has a square-shaped or circular base. In a preferred embodiment of the present invention component (B) is made from a material selected from stainless steel, nickel base alloy and ceramic. In embodiments of the present invention wherein component (B) is made from a ceramic such ceramic is selected from alumina, silicon carbide, mullite, cordierite, spinel, and from combinations of at least two of the foregoing.