Container coated with an MGAL2O4 spinel coating and corundum

Description

technical field

[0001] The present invention relates to a container whose inner wall surface is at least partially covered, preferably by more than 80%, with a coating and to the use of said container for the manufacture of a lithium oxide powder, in particular an oxide of one or more lithium-containing transition metals. Previous technique

[0002] The need for lithium-ion batteries is constantly increasing. Many of them contain a part, usually the cathode, made of an oxide containing lithium, in particular an oxide of one or more lithium transition metals, especially LiFePO4 (or LPF), LiMn2O4 (or LMO), or a lithium-nickel-cobalt-manganese oxide (or Li-NMC).

[0003] The cathode is generally manufactured by shaping a powder of said oxide of one or more transition metals in lithia.

[0004] Among the conventional manufacturing processes for these powders is the preparation of a mixture of oxides and / or various oxide precursors, followed by a heat treatment to achieve the solid-phase synthesis of the oxide of one or more lithium-containing transition metals. During this heat treatment, the mixture is placed in a container, generally called a "sagger." The synthesis conditions of these powders, as well as the mixture itself, particularly the lithium-containing elements, are especially demanding on the container.

[0005] CN103884190A and CN108083823A describe such containers having a coating for the manufacture of such powders.

[0006] There is a need to increase the lifespan of these containers.

[0007] One aim of the invention is to meet, at least partially, this need. Description of the invention

[0008] According to the invention, this goal is achieved by means of a container, the surface of the inner walls of said container being partially covered, preferably for more than 80%, and preferably over all of said inner walls, with a coating having the following crystalline phases, in mass percentage based on the total mass of the crystalline phases: Spinel MgAl 2 O 4: greater than 25% and up to 60%, and Crystalline phases other than spinel MgAl 2 O 4 and corundum: < 10%, and Corundum: complement to 100%.

[0009] The inventors discovered that the coated container according to the invention exhibited less degradation during its use, which allows for a longer service life, and in particular a greater number of manufacturing cycles of oxide powder of one or more lithia-coated transition metals.

[0010] According to preferred but non-limiting embodiments of the present invention, which may, where appropriate, be combined with each other: the coating has, as a percentage by mass based on the crystallized phases, a spinel content greater than 30%, preferably greater than 35% and / or less than 55%, preferably less than 50%; the container comprises more than 90%, preferably more than 95%, preferably more than 99%, by mass, of oxide(s), carbide(s), nitride(s), oxynitride(s), boride(s), and mixtures thereof; the coating has a thickness greater than 50 µm, preferably greater than 100 µm, preferably greater than 200 µm, preferably greater than 300 µm and less than 2000 µm, preferably less than 1500 µm, preferably less than 1000 µm, preferably less than 800 µm; the surface of the covered interior walls includes the bottom of said container and the part of the sides in contact with said bottom; the surface of the interior walls is covered for more than 85%, preferably for more than 90%, preferably for more than 95%;the coating extends over substantially the entire surface of the inner walls of said container; the container comprises more than 90%, preferably more than 95% by mass, of oxide(s), the container comprises Al 2 O 3 , MgO, ZrO 2 , SiO 2 , Y 2 O 3 , and mixtures thereof; the container has an Al 2 O 3 +MgO+ZrO 2 +SiO 2 +Y 2 O 3 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of the oxides; the container has an Al 2 O 3 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of the oxides; the container has a SiO 2 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of the oxides; the container has an Al 2 O 3 + MgO content greater than 90%, preferably greater than 95%, as a percentage by mass on the basis of oxides;the container has an Al2O3 + Y2O3 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of oxides; the container has an Al2O3 + MgO + SiO2 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of oxides; the container has an Al2O3 + ZrO2 + SiO2 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of oxides; the container has an Al2O3 + ZrO2 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of oxides; the container has an Al2O3 + SiO2 content greater than 90%, preferably greater than 95%, by mass percentage on the basis of oxides;the container comprises more than 90%, preferably more than 95%, by mass percentages based on the mass of the crystallized phases, of corundum, spinel MgAl 2 O 4, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof; the container comprises more than 90%, preferably more than 95%, by mass percentages, in total and on the basis of the mass of the crystallized phases, of corundum or mullite or a mixture of corundum and cordierite or a mixture of corundum and mullite or a mixture of corundum and spinel MgAl 2 O 4 or a mixture of corundum and cordierite and spinel, or a mixture of corundum and zirconia or a mixture of corundum and mullite and zirconia or a mixture of cordierite and mullite; the container comprises more than 90%, preferably more than 95% by mass, of carbide(s), nitride(s), oxynitride(s), boride(s) and mixtures thereof;The container comprises more than 90%, preferably more than 95% by mass, of carbide(s), nitride(s), SiAlON, and mixtures thereof; the container comprises more than 90%, preferably more than 95%, by mass, of silicon carbide, silicon nitride, SiAlON, and mixtures thereof; the container comprises more than 90%, preferably more than 95%, by mass, of a mixture of silicon carbide and silicon nitride; the container has a perimeter selected from a polygon, a circle, or an ellipse; the container has a base and at least one side, preferably with an average thickness of less than 20 mm and more than 2 mm; the container has a volume greater than 0.1 liters and less than 25 liters.

[0011] The invention also relates to the use of a container coated according to the invention for the manufacture of an oxide powder containing lithium, in particular an oxide of one or more lithium-containing transition metals. Definitions

[0012] The term "ceramic" refers to a product that is neither metallic nor organic. For the purposes of this invention, carbon is considered a ceramic product. The term "coating" refers to a layer of material(s) different in nature from the substrate, which is the container. The term "precursor" of a crystallized oxide refers to one or more materials that, after heat treatment at a temperature above 1100°C, preferably in air, will lead to said crystallized oxide. For example, a corundum precursor could be transition alumina, boehmite, or aluminum trihydroxide. For clarity, the chemical formulas of simple oxides are used to designate the contents of these oxides in a composition. For example, "MgO" or "Al₂O₃" designate the contents of these simple oxides in the composition under consideration, while "magnesia,"The terms "alumina" and "MgO" are used to refer to the actual presence of the phases of these oxides, composed of MgO and Al₂O₃, respectively. "Corundum" classically refers to alumina in its rhombohedral crystallographic form. A "sialon", SiAlON, is an oxynitride compound of at least the elements Si, Al and N, in particular a compound conforming to one of the following formulas: Si x Al y O u N v , in which: x is greater than or equal to 0, greater than 0.05, greater than 0.1 or greater than 0.2, and less than or equal to 1, less than or equal to 0.8 or less than or equal to 0.4, y is greater than or equal to 0, or greater than 0.1, greater than 0.3 or greater than 0.5, and less than or equal to 1, u is greater than 0, greater than 0.1 or greater than 0.2, and less than or equal to 1 or less than or equal to 0.7, v is greater than 0, greater than 0.1, greater than 0.2 or greater than 0.5, or greater than 0.7, and less than or equal to 1, x+y > 0, x, y,u and v being stoichiometric indices normalized to the highest, made equal to 1; Me x Si 12-(m+n) Al (m+n) O n N 16-n , with 0 ≤ x ≤ 2, Me a cation chosen from the lanthanide cations, Fe, Y, Ca, Li and their mixtures, 0 ≤ m ≤ 12, 0 ≤ n ≤ 12 and 0 < n+m ≤ 12, generally called "α'-SiAlON" or "SiAlON-α'". Unless otherwise stated, all oxide contents are mass percentages on an oxide basis. A mass content of an oxide of a metallic element refers to the total content of that element expressed in the form of the most stable oxide, according to the usual industry convention. The sum of oxide contents does not imply the presence of all such oxides. "Contains" or "includes" should be interpreted in a non-limiting manner, meaning that elements other than those indicated may be present. Detailed description Container

[0013] The container is preferably made of ceramic.

[0014] Preferably, the container comprises more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5%, by mass, of oxide(s), carbide(s), nitride(s), oxynitride(s), boride(s), and mixtures thereof.

[0015] Preferably, the container contains more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5%, by mass: of oxide(s), or of carbide(s), of nitride(s), of oxynitride(s), of borides and mixtures thereof, preferably of carbide(s), of nitride(s), of oxynitride(s) and mixtures thereof, preferably of carbide(s), of nitride(s), of SiAlON and mixtures thereof, preferably of carbide(s), of nitride(s) and mixtures thereof, preferably of silicon carbide, of silicon nitride and mixtures thereof.

[0016] In a first embodiment, the container comprises more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5%, by mass of oxide(s).

[0017] Preferably the said oxide(s) are chosen from or comprise Al 2 O 3 , MgO, ZrO 2 , SiO 2 , Y 2 O 3 , and mixtures thereof.

[0018] Preferably, the container has an Al 2 O 3 +MgO+ZrO 2 +SiO 2 +Y 2 O 3 content greater than 90%, preferably greater than 95%, preferably greater than 98%, as a percentage by mass on the basis of the oxides.

[0019] Preferably, the container has an Al 2 O 3 +MgO+ZrO 2 +SiO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, as a percentage by mass on the basis of oxides.

[0020] Preferably, the container has an Al 2 O 3 +MgO+SiO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, as a percentage by mass on the basis of oxides.

[0021] In one embodiment of said first embodiment, the container has an Al 2 O 3 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0022] In one embodiment of said first embodiment, the container has a SiO2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of oxides.

[0023] In one embodiment of said first embodiment, the container has an Al 2 O 3 + MgO content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0024] In one embodiment of said first embodiment, the container has an Al 2 O 3 + Y 2 O 3 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0025] In one embodiment of said first embodiment, the container has an Al 2 O 3 + MgO + SiO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0026] In one embodiment of said first embodiment, the container has an Al 2 O 3 + ZrO 2 + SiO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0027] In one embodiment of said first embodiment, the container has an Al 2 O 3 + ZrO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0028] In one embodiment of said first embodiment, the container has an Al 2 O 3 + SiO 2 content greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, as a percentage by mass on the basis of the oxides.

[0029] Preferably, the container comprises more than 90%, preferably more than 95%, in total, by mass percentages based on the mass of the crystallized phases, of corundum, spinel MgAl₂O₄, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof. Even more preferably, the container comprises more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5%, in total, by mass percentages based on the mass of the crystallized phases, of corundum, spinel MgAl₂O₄, cordierite, mullite, zirconia, optionally stabilized, and mixtures thereof.

[0030] Preferably, the container comprises more than 90%, preferably more than 95%, by mass percentages based on the mass of the crystallized phases, of corundum or mullite or a mixture of corundum and cordierite or a mixture of corundum and mullite or a mixture of corundum and spinel MgAl 2 O 4 or a mixture of corundum and cordierite and spinel, or a mixture of corundum and zirconia or a mixture of corundum and mullite and zirconia or a mixture of cordierite and mullite.

[0031] In a second embodiment, the container comprises more than 90%, preferably more than 95%, preferably more than 99%, preferably more than 99.5%, of carbide(s), nitride(s), oxynitride(s), borides and mixtures thereof, preferably of carbide(s), nitride(s), oxynitride(s) and mixtures thereof, preferably of carbide(s), nitride(s), SiAlON and mixtures thereof.

[0032] Preferably, the container comprises more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, by mass, of silicon carbide, silicon nitride, SiAlON, and mixtures thereof.

[0033] In one embodiment of said second embodiment, the container comprises more than 90% silicon carbide and the remainder comprises metallic silicon.

[0034] Preferably, the container comprises more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, by mass, of silicon carbide, silicon nitride, and mixtures thereof.

[0035] In one embodiment of said second embodiment, the container comprises more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, by mass, of silicon carbide.

[0036] In one embodiment of said second embodiment, the container comprises more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, by mass, of a mixture of silicon carbide and silicon nitride, preferably, the mass ratio of the quantity of silicon carbide to the quantity of silicon nitride being greater than 1, preferably greater than 2 and less than 10, preferably less than 8, preferably less than 6.

[0037] Preferably, the container comprises more than 90%, preferably more than 95%, in total, as mass percentages based on the mass of the crystallized phases: of corundum, spinel MgAl 2 O 4, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof, preferably of corundum, spinel MgAl 2 O 4, cordierite, mullite, zirconia, optionally stabilized, and mixtures thereof, preferably of corundum, spinel, cordierite and mixtures thereof, or of silicon carbide, silicon nitride, and mixtures thereof.

[0038] The container can have any shape.

[0039] The perimeter of said container according to the invention can be chosen from a polygon, in particular a rectangle and a square, a circle or an ellipse.

[0040] Preferably, the container according to the invention comprises a bottom and at least one side, preferably having an average thickness, preferably less than 20 mm, preferably less than 15 mm, or even less than 10 mm, or / or preferably greater than 2 mm, preferably greater than 4 mm, preferably greater than 5 mm.

[0041] In one embodiment, the bottom of said container has a greater thickness than its side, preferably 10% greater, preferably 20% greater, preferably 30% greater.

[0042] In one embodiment, the bottom and side of said container have a thickness difference of less than 10%, preferably less than 5%. Preferably, in said embodiment, the bottom of said container has a thickness substantially identical to that of its side.

[0043] In one embodiment, the wall thickness is not constant. Preferably, the side thickness is greater on the side facing the container base. Preferably, the portion of the sides in contact with the container base is 10% thicker than the portion of the sides on the opposite side of the container base. In one embodiment, the container has a length (i.e., the greatest length less than 500 mm, preferably less than 400 mm, and / or preferably more than 100 mm, preferably more than 200 mm) and a width (i.e., the smallest dimension measured perpendicular to the length) less than 500 mm, preferably less than 400 mm, and / or preferably more than 100 mm, preferably more than 200 mm.

[0044] In one embodiment, the angle between the bottom of the container and at least one side is equal to 90°. In another embodiment, said angle is greater than 90° and less than 100°.

[0045] In one embodiment, the container has a diameter of less than 500 mm, preferably less than 400 mm, and / or preferably greater than 100 mm, preferably greater than 200 mm.

[0046] Preferably, the container has a volume greater than 0.1 litre, preferably greater than 1 litre, preferably greater than 2 litres, preferably greater than 3 litres and / or preferably less than 25 litres, preferably less than 20 litres, preferably less than 15 litres.

[0047] In a preferred embodiment, the base and sides of the container form a monolithic unit. In other words, said base and sides are a single piece, the connection between the base and the sides having a radius, preferably greater than 5 mm, preferably greater than 10 mm, preferably greater than 20 mm.

[0048] In one embodiment, the container is an assembly of different parts, for example plates, the connection between said different parts being able in particular to be made using tenon-mortise type assembly, and / or suspension assembly, and / or inset (using in particular notches or grooves), and / or ceramic dowels, and / or ceramic screws and / or ceramic rivets, and / or ceramic keys. Coating

[0049] The coating exhibits the following crystalline phases, expressed as a percentage by mass based on the crystalline phases: Spinel MgAl 2 O 4: more than 25% and up to 60%, and Crystalline phases other than spinel MgAl 2 O 4 and corundum: < 10% Corundum: complement to 100%.

[0050] The crystalline phases present in the coating can conventionally be highlighted by X-ray diffraction on said coating.

[0051] The diffraction pattern was acquired using a Bruker D8 Endeavor instrument, over an angular range 2θ from 5° to 80°, with a step size of 0.01° and a counting time of 0.34 s / step. The front optics consisted of a 0.3° primary slit and a 2.5° Soller slit. The sample was rotated at 5 rpm using an automatic cutter. The rear optics included a 2.5° Soller slit, a 0.0125 mm nickel filter, and a 1D detector with a 4° aperture.

[0052] The diffraction patterns are then qualitatively analyzed using EVA software and the ICDD2016 database.

[0053] Once the phases present have been identified, the diffraction patterns are quantitatively analyzed using High Score Plus software by Rietveld refinement according to the following strategy: Background signal refinement is performed using the "treatment" function, "determine background" with the following choices: "bending factor" equal to 1 and "granularity" equal to 40; Conventionally, the ICDD sheets of the present phases that are highlighted and quantifiable are selected, and therefore taken into account in the refinement; An automatic refinement is then performed by selecting the previously determined background signal "use available background" and selecting the mode "automatic: option phase fit-default Rietveld"; A manual refinement of the "B overall" parameter of all the selected phases is then performed simultaneously.

[0054] The inventors have shown that such a coating makes it possible to increase the life of the container when manufacturing a powder of oxides containing lithium, in particular an oxide of one or more lithium-containing transition metals.

[0055] The inventors also highlighted that a coating with a spinel content of MgAl 2 O 4 greater than 60% exhibited cracking and / or delamination of the container surface when rising to the operating temperature, which prevented the container with such a coating from having an improved lifespan.

[0056] A coated container with a coating having a spinel content of less than 10% MgAl 2 O 4 does not have an improved service life.

[0057] Preferably, the coating has a spinel content MgAl 2 O 4 greater than 30%, preferably greater than 35%, and preferably less than 55%, preferably less than 50%, as a percentage by mass on the basis of the crystallized phases.

[0058] Preferably, the coating has a content of crystalline phases other than spinel (MgAl₂O₄) and corundum of less than 8%, preferably less than 5%, by mass percentage based on the crystalline phases. Preferably, the coating has a content of crystalline phases other than spinel (MgAl₂O₄) and corundum that is substantially zero.

[0059] Preferably, the coating has an amount of amorphous phases less than 10%, preferably less than 5%, preferably substantially zero.

[0060] Preferably, the coating has the following chemical composition, expressed as a percentage by mass based on oxides: MgO: > 2.8%, preferably > 4%, preferably > 5.5%, preferably > 7%, preferably > 8.5%, and preferably < 16.9%, preferably < 15.5%, preferably < 14%, and / or Al 2 O 3: > 73.1%, preferably > 75%, preferably > 78%, preferably > 80%, preferably > 83%, and preferably < 97%, preferably < 95%, preferably < 92%, preferably < 90%, and / or Oxides other than MgO and Al 2 O 3: <10%, preferably < 8%, preferably < 6%, preferably < 5%, preferably < 3%, preferably < 1%, preferably < 0.5%.

[0061] Preferably, the coating consists of more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%, preferably more than 99.5% by mass of oxides. Preferably, the coating consists essentially of oxides.

[0062] The thickness of said coating is preferably greater than 50 µm, preferably greater than 100 µm, preferably greater than 200 µm, preferably greater than 300 µm, or even greater than 400 µm, or even greater than 500 µm, or even greater than 600 µm and / or preferably less than 2000 µm, preferably less than 1500 µm, preferably less than 1000 µm, preferably less than 800 µm.

[0063] Preferably, the coated surface of the inner walls includes the bottom of the container and the portion of the sides in contact with said bottom. In other words, the coating extends over the lower inner portion of the container's sides, the container being considered in its operating position, said portion being the one in contact with the powders during the use of said container.

[0064] Preferably, the surface of the container's interior walls is covered by more than 85%, preferably more than 90%, preferably more than 95%, preferably more than 96%, preferably more than 98%, preferably more than 99% of said coating. Preferably, the coating extends over substantially the entire surface of the container's interior walls.

[0065] Preferably, at least part, preferably the entire surface of the outer wall of the bottom is covered with the coating.

[0066] In one embodiment, more than 90%, preferably more than 95%, preferably more than 99%, of the total surface area of ​​the container walls is covered with the coating.

[0067] The coating can be applied to at least part of the surface of the container's inner walls using any technique known to those skilled in the art, in particular by brush application, spraying (especially wet spraying), vacuum impregnation, or immersion. Preferably, the coating is applied by wet spraying with a suspension comprising one or more MgAl₂O₄ spinel powders and one or more corundum or corundum precursor powders. Preferably, the suspension does not contain corundum precursor powders.

[0068] Preferably the coating has undergone heat treatment before use, the maximum temperature reached during said heat treatment being preferably greater than 1100°C, preferably greater than 1200°C, and preferably less than 1500°C, preferably less than 1400°C.

[0069] Preferably the time spent at said maximum temperature is greater than 0.5 hours, and less than 5 hours, preferably less than 2 hours. Examples

[0070] The following non-limiting examples are given for the purpose of illustrating the invention. Example manufacturing protocol

[0071] To manufacture the examples, tiles measuring 50 x 50 x 10 mm are machined on all 6 sides from sheets of N-Durance product marketed by Saint-Gobain Performance Ceramics and Refractories.

[0072] One large face of each tile is then coated by wet spraying with a suspension.

[0073] The suspensions used to obtain the different coatings are manufactured in the following way.

[0074] A mixture M of alumina powders with a mass purity greater than 99% and an aluminum hydroxide powder is prepared. Said mixture M has a median size D 50 equal to 7 µm and a D 90 equal to 51 µm.

[0075] Mixtures are then made, in accordance with the following table 1, in mass percentages. [Table 1] Mixture for coating example 1 Mixture for coating example 2 Mixture for coating example 3 Mixture for coating example 4 Mixture M 100 85 70 55 AR78 spinel powder, -90 µm, marketed by Almatis 0 15 30 45

[0076] Then, to each mixture are added 0.3% of sodium silicate, 0.5% of a solution of a stabilizer to prevent segregation in the coating when applied to the tiles, and alumina beads, the percentages of sodium silicate and said stabilizer suspension being mass percentages based on the total mass of mixture M and spinel powder.

[0077] The mixture is placed in a container and rotated on a jar turner for 10 minutes to mix the different ingredients.

[0078] Then, 40% water and 2.5% of an adhesive dispersion are added to the container, allowing in particular to achieve sufficient abrasion resistance of the coating, the percentages being mass percentages based on the total mass of the M mixture and the spinel powder.

[0079] The container is resealed and then rotated on a jar turner for 8 hours to obtain a homogeneous suspension.

[0080] The beads are then separated from the suspension by sieving.

[0081] The suspension is then placed in a compressed air gun and projected onto a large face of a tile, so as to obtain a coating of substantially uniform thickness equal to 300 µm after the consolidation step by sintering.

[0082] Then the coated tile is dried in an oven for 12 hours at 70°C.

[0083] Finally, the coated tile undergoes the following heat treatment for consolidation, in an electric oven, under air: Rising to 1450°C at a rate of 300 °C / h, Maintaining at 1450°C for 1 hour, Descending to 500 °C at a rate of 300 °C / h, then free descent.

[0084] The coated tiles thus obtained then undergo the degradation resistance test described below: The resistance to degradation by a powder of a lithium-nickel-cobalt-manganese oxide Li-NMC is evaluated on the coated tiles previously described according to examples 1 to 4, the surface of the tile in contact with the powder being the surface presenting the coating previously described.

[0085] The lithium-nickel-cobalt-manganese oxide powder used is manufactured as follows: A Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 powder is obtained by co-precipitation of an aqueous solution of nickel nitrate, cobalt nitrate and manganese nitrate, present in a stoichiometric ratio of 0.8:0.1:0.1, with the addition of NaOH and NH 4 OH, at a temperature of 50°C, under stirring.

[0086] After drying of the precipitate, LiOH.H 2 O is added to the Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 powder in a molar ratio of LiOH.H 2 O to Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 equal to 1.03, the whole being then mixed vigorously.

[0087] Then, the whole thing is heat-treated at 480°C for 4 hours.

[0088] The powder obtained after heat treatment is clumped in an agate mortar. The powder obtained after clumping is the powder used in the degradation resistance test.

[0089] For each example, 4.5 g of said powder are placed on the central part of the tile to be tested, taking care not to cover the surface of the periphery of said tile with powder.

[0090] The tiles are then placed in an electric tubular kiln, the tube being made of alumina, to undergo the following heat treatment cycle: Rising to 800°C at a rate of 200°C / h. Maintaining the temperature at 800°C for 10 hours. Descending to 500°C at a rate of 200°C / h, then free descent to ambient temperature.

[0091] Throughout the heat treatment, oxygen circulation is set up in the tube, with a flow rate of 20 l / min.

[0092] The tiles are then removed from the kiln. The powder on top of the tile is removed, and 4.5 g of fresh powder is sprinkled onto the central part of the tile to be tested, taking care not to cover the surface around the edge with powder. The tiles are then placed in the electric tube kiln, the tube of which is made of alumina, to undergo a second heat treatment cycle identical to the first.

[0093] The tiles are then removed from the kiln. The powder on top of the tile is removed. The same protocol as previously described is repeated three more times so that each tile undergoes a total of five heat treatment cycles in the presence of the previously described powder.

[0094] The tiles are then removed from the kiln, and each tile is cut to obtain a slice of its central area. This slice is then coated with resin and polished to a mirror finish. Each polished sample is then examined using a scanning electron microscope at magnifications ranging from 200x to 500x.

[0095] Table 2 below summarizes the results obtained. [Table 2] Example Quantity of spinel in the coating, as a mass percentage Visual condition of the coating after the degradation resistance test 1 0 The coating has almost completely disappeared 2 15 Several cracks are present from the outer surface of the coating to the interface between the coating and the supporting tile. 3 30 There are some cracks on the outer surface of the coating, but they do not extend to the interface between the coating and the supporting tile. 4 45 No crack

[0096] A comparison of examples 1, and 2 to 4, shows that the coating in examples 2 to 4 is still present after the degradation resistance test, unlike the coating in example 1 which has almost completely disappeared.

[0097] A comparison of examples 2 to 4 shows, however, that the coating in example 2, which has a spinel content of 15%, has several cracks, present from the outer surface of the coating to the coating-support tile interface.

[0098] The coating in Example 3, containing 30% spinel, exhibits, after a degradation resistance test, some cracks on the outer surface of the coating that do not extend to the coating-substrate tile interface.

[0099] The coating in Example 4, containing 45% spinel, exhibits the best resistance, with no cracks visible after degradation resistance testing. These results demonstrate the effectiveness of a container according to the invention.

[0100] Of course, the present invention is not limited to the embodiments described, which are provided by way of illustrative and non-limiting examples.

[0101] In particular, the products according to the invention are not limited to particular shapes or dimensions.

Claims

1. A container for manufacturing an oxide powder comprising lithium, the surface of the inner walls thereof is at least partially covered, preferably by more than 80%, with a coating having the following crystalline phases, as a percentage and based on the total weight of the crystalline phases: - MgAl2O4 spinel: more than 25% and up to 60%, and - Crystalline phases other than MgAl2O4 spinel and corundum: < 10% - Corundum: supplemented to 100%.

2. The container according to the preceding claim: - wherein the coating has, as a weight percentage based on the crystalline phases, a spinel content greater than 30% and / or less than 55%, and / or - comprising more than 90%, by weight, of oxide(s), carbide(s), nitride(s), oxynitride(s), boride(s), and mixtures thereof, and / or - wherein the thickness of said coating is greater than 50 µm and less than 2000 µm, and / or - wherein the surface of the inner walls covered by said coating comprises the bottom of said container and the part of the sides being in contact with said bottom, and / or - the surface of the inner walls thereof is covered by more than 85% with said coating.

3. The container according to claim 1 or 2: - wherein the coating has, as a weight percentage based on the crystalline phases, a spinel content greater than 35% and / or less than 50%, and / or - comprising more than 95%, by weight, of oxide(s), carbide(s), nitride(s), oxynitride(s), boride(s), and mixtures thereof, and / or - wherein the thickness of said coating is greater than 100 µm and less than 1500 µm, and / or - the surface of the inner walls thereof is covered by more than 90% with said coating.

4. The container according to one of claims 1 to 3: - comprising more than 99%, by weight, of oxide(s), carbide(s), nitride(s), oxynitride(s), boride(s), and mixtures thereof, and / or - wherein the thickness of said coating is greater than 200 µm and less than 1000 µm, and / or - the surface of the inner walls thereof is covered by more than 95% with said coating.

5. The container according to one of the preceding claims - wherein the thickness of said coating is greater than 300 µm and less than 800 µm, and / or - the coating thereof extends substantially over the entire surface of the inner walls of said container.

6. The container according to one of the preceding claims, comprising more than 90%, preferably more than 95% by weight, of oxide(s).

7. The container according to the preceding claim, comprising Al2O3, MgO, ZrO2, SiO2, Y2O3, and mixtures thereof.

8. The container according to one of the preceding claims, having an Al2O3+MgO+ZrO2+SiO2+Y2O3 content greater than 90%, preferably greater than 95%, as an oxide weight percentage.

9. The container according to one of the preceding claims, having - an Al2O3 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an SiO2 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + MgO content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + Y2O3 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + MgO + SiO2 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + ZrO2 + SiO2 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + ZrO2 content greater than 90%, preferably greater than 95%, as an oxide weight percentage, or - an Al2O3 + SiO2 content greater than 90%, preferably greater than 95%, as an oxide weight percentage.

10. The container according to one of the preceding claims, comprising more than 90%, preferably more than 95%, in total and as a percentage based on the total weight of the crystalline phases, of corundum, MgAl2O4 spinel, cordierite, mullite, zirconia, optionally stabilized, periclase, and mixtures thereof.

11. The container according to the preceding claim, comprising more than 90%, preferably more than 95%, in total and as a percentage based on the total weight of the crystalline phases, of corundum or mullite or a mixture of corundum and cordierite or a mixture of corundum and mullite or a mixture of corundum and MgAl2O4 spinel or a mixture of corundum and cordierite and spinel, or a mixture of corundum and zirconia or a mixture of corundum and mullite and zirconia or a mixture of cordierite and mullite.

12. The container according to one of claims 1 to 5, comprising more than 90%, preferably more than 95% by weight, of carbide(s), nitride(s), oxynitride(s), borides and mixtures thereof.

13. The container according to the preceding claim, comprising more than 90%, preferably more than 95% by weight, in total, of carbide(s), nitride(s), SiAlON and mixtures thereof.

14. The container according to the preceding claim, comprising more than 90%, preferably more than 95%, by weight and in total, of silicon carbide, silicon nitride, SiAlON, and mixtures thereof.

15. The container according to the preceding claim, comprising more than 90%, preferably more than 95%, by weight, of a mixture of silicon carbide and silicon nitride.

16. The container according to one of the preceding claims, - having a perimeter chosen from a polygon, a circle or an ellipse, and / or - comprising a bottom and at least one side, preferably having an average thickness of less than 20 mm and greater than 2 mm, and / or - has a volume greater than 0.1 liters and less than 25 liters.

17. The container according to one of the preceding claims, for manufacturing an oxide powder of a metal or of several lithiated transition metals.