Porous corrosion-resistant sagger as well as preparation method and application thereof

Abstract

The invention discloses a porous corrosion-resistant sagger and a preparation method and application thereof. The porous corrosion-resistant sagger comprises a sagger body and a porous recrystallized silicon carbide layer attached to the inner surface of the sagger body. The porous recrystallized silicon carbide layer is formed by preparing two kinds of silicon carbide with different particle size ratios into slurry, coating the surface of the sagger main body layer with the slurry, and then performing high-temperature recrystallization under a vacuum or argon condition; the content of silicon carbide in the porous recrystallized silicon carbide layer is greater than or equal to 99.4%, the pore size is 2-20 [mu] m, and the porosity is 16-20%; when the porous corrosion-resistant sagger is used in the sintering process of a positive electrode material, due to the action of the porous recrystallized silicon carbide layer, the service life of the porous corrosion-resistant sagger is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and particularly relates to a porous corrosion-resistant crucible and a preparation method and application thereof. Background Art

[0002] With the development of the new energy industry, people's demand for cathode materials is increasing. The cathode materials are mainly prepared by the high-temperature solid-phase synthesis method. The preparation process is mainly as follows: placing the ternary material precursor and the lithium salt precursor in a roasting container crucible, and subjecting them to high-temperature roasting in a roller hearth kiln or a pusher kiln. After passing through processes such as pulverization, classification, and demagnetization, the finished cathode material is finally formed. Among them, the roasting stage is the process with the highest energy consumption and the greatest impact on product performance in the whole process; the crucible materials used in this process mainly include mullite and cordierite. Among them, mullite has a lower softening temperature, higher mechanical strength, but a higher thermal expansion coefficient. Cordierite has a lower thermal expansion coefficient, better thermal shock resistance, and no anisotropy. The mullite-cordierite composite crucible prepared by mixing mullite and cordierite in an appropriate ratio can achieve the effect of complementing each other's advantages and thus obtain higher mechanical strength and thermal shock resistance.

[0003] However, side reactions will occur during the sintering process of the cathode material, that is, lithium oxide generated by the decomposition of the lithium precursor is prone to react with the crucible, and a metamorphic layer is formed on the surface of the crucible. Due to the different thermal expansion coefficients of the surface metamorphic layer and the crucible substrate, the change in temperature during the cyclic roasting process causes cracking and peeling of the surface metamorphic layer, ultimately resulting in the scrapping of the crucible and a short service life. Summary of the Invention

[0004] Embodiments of the present invention provide a porous corrosion-resistant crucible and a preparation method and application thereof, aiming to solve the problem that side reactions occur between the cathode material and the crucible during the sintering process, resulting in the formation of a metamorphic layer on the surface of the crucible, thereby affecting the service life of the crucible.

[0005] In the present invention, silicon carbide of two particle sizes is mixed evenly and then coated on the inner surface of the crucible body. After high-temperature treatment, the silicon carbide mixed powder is recrystallized to form a porous recrystallized silicon carbide layer, and a porous corrosion-resistant crucible is obtained; on the one hand, the porous recrystallized silicon carbide layer can isolate the contact between the cathode material and the crucible body, reducing the occurrence of side reactions. On the other hand, the porosity and pore diameter of the porous recrystallized silicon carbide layer are both large, and the material is relatively loose. The side reactions of the cathode material can all penetrate into the interior of the silicon carbide layer and occur in the internal pores. The volume expansion effect accompanied by the reaction can be dispersed to a deeper position of the crucible body, but it has little impact on the local structure of the mullite-cordierite material of the crucible body, thereby improving the service life of the crucible.

[0006] To this end, in a first aspect, an embodiment of the present invention provides a porous corrosion-resistant crucible, which includes a crucible body and a porous recrystallized silicon carbide layer attached to the inner surface of the crucible body;

[0007] The porous recrystallized silicon carbide layer is formed by making slurries of two silicon carbides with different particle size ratios, coating the slurries on the surface of the crucible body layer, and then undergoing high-temperature recrystallization under vacuum or argon conditions;

[0008] The silicon carbide content in the porous recrystallized silicon carbide layer is ≥99.4%, the pore size is 2 μm - 20 μm, and the porosity is 16% - 20%.

[0009] Preferably, the crucible body includes: a mullite-cordierite crucible;

[0010] The thickness of the porous recrystallized silicon carbide layer is 2 mm - 6 mm.

[0011] Preferably, the two silicon carbides with different particle size ratios are respectively first silicon carbide and second silicon carbide;

[0012] The particle size D50 of the first silicon carbide is between 1.5 μm and 3.5 μm;

[0013] The particle size D50 of the second silicon carbide is between 10 μm and 20 μm;

[0014] The mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:8.

[0015] In a second aspect, an embodiment of the present invention provides a preparation method for the porous corrosion-resistant crucible described in the first aspect above. The preparation method includes:

[0016] Placing the first silicon carbide and the second silicon carbide in a mixing device, mixing them evenly to obtain a silicon carbide mixed powder;

[0017] Coating the silicon carbide mixed powder on the inner surface of the crucible body to obtain a pretreated crucible;

[0018] Placing the pretreated crucible in a kiln furnace, and under vacuum or argon conditions, through high-temperature treatment, enabling the silicon carbide mixed powder to undergo high-temperature recrystallization to form a porous recrystallized silicon carbide layer, thereby obtaining a porous corrosion-resistant crucible.

[0019] Preferably, the particle size D50 of the first silicon carbide is between 1.5 μm and 3.5 μm;

[0020] The particle size D50 of the second silicon carbide is between 10 μm and 20 μm;

[0021] The mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:8.

[0022] Preferably, the mixing device includes: a high-speed mixer.

[0023] Preferably, the crucible body is a mullite-cordierite crucible;

[0024] The coating method includes: one or more of spraying, extrusion coating, or scraping coating;

[0025] The temperature of the high-temperature treatment is 2300°C - 2450°C, and the heat preservation time is 1 hour - 4 hours.

[0026] Preferably, the thickness of the porous recrystallized silicon carbide layer is 2 mm - 6 mm, the silicon carbide content is ≥99.4%, the pore size is 2 μm - 20 μm, and the porosity is 16% - 20%.

[0027] In a third aspect, an embodiment of the present invention provides an application of the porous corrosion-resistant crucible described in the first aspect above. The porous corrosion-resistant crucible is used in the sintering treatment process for preparing a cathode material.

[0028] Preferably, the cathode material includes a ternary cathode material or a lithium cobalt oxide cathode material.

[0029] An embodiment of the present invention provides a method for preparing a porous corrosion-resistant crucible. By uniformly mixing two particle sizes of silicon carbide and coating it on the inner surface of the crucible body, and then through high-temperature treatment, the silicon carbide mixed powder is recrystallized to form a porous recrystallized silicon carbide layer, obtaining a porous corrosion-resistant crucible; this preparation method is simple in operation and easy to realize large-scale production.

[0030] For the porous corrosion-resistant crucible provided by an embodiment of the present invention, since there is a layer of porous recrystallized silicon carbide on the crucible body, on the one hand, this porous recrystallized silicon carbide layer can isolate the contact between the cathode material and the crucible body, reducing the occurrence of side reactions. On the other hand, the porosity and pore size of the porous recrystallized silicon carbide layer are both large, and the material is relatively loose. The side reactions of the cathode material can all penetrate into the interior of the silicon carbide layer and occur in the internal pores. The volume expansion effect accompanied by the reaction can be dispersed to a deeper position of the crucible body, but it has little impact on the local structure of the mullite-cordierite material of the crucible body, thereby improving the service life of the crucible. Description of the Drawings

[0031] The technical solutions of the embodiments of the present invention will be further described in detail below through the drawings and embodiments.

[0032] Figure 1 It is a flowchart of the method for preparing a porous corrosion-resistant crucible provided by an embodiment of the present invention.

[0033] Figure 2 It is a comparison diagram of the surface states of the porous corrosion-resistant crucible provided in Embodiment 1 of the present invention and the conventional mullite-cordierite crucible of Comparative Example 2 after 30 uses. Specific Embodiments

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any way, that is, it is not intended to limit the protection scope of the present invention.

[0035] The embodiment of the present invention provides a porous corrosion-resistant crucible, which includes a crucible body and a porous recrystallized silicon carbide layer attached to the inner surface of the crucible body.

[0036] Among them, the crucible body is a mullite-cordierite crucible;

[0037] The porous recrystallized silicon carbide layer is formed by coating a slurry made of two silicon carbides with different particle size ratios on the surface of the crucible body layer and then undergoing high-temperature recrystallization under vacuum or argon conditions; the thickness of the porous recrystallized silicon carbide layer is 2 mm - 6 mm; the silicon carbide content in the porous recrystallized silicon carbide layer is ≥ 99.4%, the pore size is 2 μm - 20 μm, and the porosity is 16% - 20%.

[0038] The above two silicon carbides with different particle size ratios are respectively the first silicon carbide and the second silicon carbide; the particle size D50 of the first silicon carbide is between 1.5 μm and 3.5 μm; the particle size D50 of the second silicon carbide is between 10 μm and 20 μm; the mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:8.

[0039] The embodiment of the present invention provides a preparation method for the above porous corrosion-resistant crucible, as Figure 1 shown, which specifically includes the following steps:

[0040] Step 110, placing the first silicon carbide and the second silicon carbide in a mixing device, mixing evenly to obtain a silicon carbide mixed powder;

[0041] Among them, the particle size D50 of the first silicon carbide is between 1.5 μm and 3.5 μm;

[0042] The particle size D50 of the second silicon carbide is between 10 μm and 20 μm;

[0043] The mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:8.

[0044] The mixing device is a high-speed mixer, and the rotation speed is between 400 rpm and 600 rpm, which can make the silicon carbide particles of the two particle sizes mix evenly.

[0045] Step 120: Coat the inner surface of the crucible body with a silicon carbide mixed powder to obtain a pretreated crucible;

[0046] wherein, the crucible body is a mullite-cordierite crucible;

[0047] The method of coating the inner surface of the crucible body with the silicon carbide mixed powder includes, but is not limited to, one or more of spraying, extrusion coating, or scraping, as long as the silicon carbide mixed powder can be evenly coated on the inner surface of the mullite-cordierite crucible.

[0048] Step 130: Place the pretreated crucible in a kiln and, under vacuum or argon conditions, perform high-temperature treatment to cause the silicon carbide mixed powder to undergo high-temperature recrystallization to form a porous recrystallized silicon carbide layer, thereby obtaining a porous corrosion-resistant crucible;

[0049] wherein, the temperature of the high-temperature treatment is 2300°C - 2450°C, and the heat preservation time is 1 hour - 4 hours.

[0050] In this application, two kinds of silicon carbide with different particle sizes and ratios are selected, namely the first silicon carbide and the second silicon carbide; wherein, the particle size D50 of the first silicon carbide is between 1.5 μm and 3.5 μm, and can be any value within this particle size range, such as 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3.0 μm, 3.2 μm, 3.5 μm, but is not limited to the listed values, and other unlisted values within this value range are equally applicable; the particle size D50 of the second silicon carbide is between 10 μm and 20 μm, and can be any value within this particle size range, such as 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, but is not limited to the listed values, and other unlisted values within this value range are equally applicable; the mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:8, and can be any ratio within this mass ratio range, such as 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, but is not limited to the listed values, and other unlisted values within this value range are equally applicable; if the particle sizes of the first silicon carbide and the second silicon carbide are not within the above ranges, it will cause the pore size of the formed porous recrystallized silicon carbide layer to be too large or too small, both of which will lead to a decrease in the corrosion resistance of the crucible.

[0051] In this application, silicon carbide with two particle sizes is used. The purpose is to use silicon carbide with a large particle size as the framework, and silicon carbide with a small particle size is filled in the voids of the large particles. Under high-temperature conditions, the small particles evaporate, condense, and recrystallize, promoting the growth of the large particles. Then, a recrystallized silicon carbide coating with certain pores is formed on the inner surface of the mullite-cordierite crucible. The thickness of the porous recrystallized silicon carbide layer is between 2 mm and 6 mm, the silicon carbide content is ≥ 99.4 wt%, the pore size is 2 μm - 20 μm, and the porosity is 16% - 20%.

[0052] The porous corrosion-resistant crucible prepared by the above preparation method in the embodiment of the present invention can be used in the sintering treatment process for preparing the positive electrode material, especially for the sintering treatment process in the preparation process of the ternary positive electrode material or the lithium cobalt oxide positive electrode material. Since there is a layer of porous recrystallized silicon carbide layer on the main body of the porous corrosion-resistant crucible of the present invention, on the one hand, this porous recrystallized silicon carbide layer can isolate the contact between the positive electrode material and the crucible main body, reducing the occurrence of side reactions. On the other hand, the porosity and pore size of the porous recrystallized silicon carbide layer are both large, and the material is relatively loose. The side reactions of the positive electrode material can all penetrate into the interior of the silicon carbide layer and occur in the internal pores. The volume expansion effect accompanied by the reaction can be dispersed to a deeper position of the crucible main body, but it has little impact on the local structure of the mullite-cordierite material of the crucible main body, thereby improving the service life of the crucible.

[0053] To better understand the technical solution provided by the present invention, the following uses specific examples to separately illustrate the preparation method and characteristics of the porous corrosion-resistant crucible of the present invention.

[0054] Example 1

[0055] This example provides a porous corrosion-resistant crucible, its preparation method and application. The specific process is as follows:

[0056] (1) Place 1 kg of the first silicon carbide with a D50 of 2 μm and 5 kg of the second silicon carbide with a D50 of 15 μm in a high-speed mixer, with a rotation speed of 400 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0057] (2) Spray the silicon carbide mixed powder on the inner surface of the mullite-cordierite crucible to obtain a pretreated crucible.

[0058] (3) Place the pretreated crucible in a kiln furnace, and under vacuum conditions, heat it to 2380 °C and hold for 2 hours to obtain a porous corrosion-resistant crucible.

[0059] The performance of the porous corrosion-resistant crucible of this embodiment was tested. The porous corrosion-resistant crucible of this embodiment was used in the process of preparing the lithium cobaltate cathode material. The specific process was as follows: Cobalt tetroxide and lithium hydroxide were mixed evenly to obtain a mixed material, which was placed in the porous corrosion-resistant crucible of Example 1, and multiple high-temperature heating and cooling experiments were carried out. Among them, the specific method of the experiment was to put the porous corrosion-resistant crucible containing the mixed material into a high-temperature furnace, heat it to 900 °C and keep it warm for 18 hours, and then cool it. The processes of heating, keeping warm, and cooling were repeated. When a small amount of shedding occurred on the inner surface of the porous corrosion-resistant crucible, the shedding would increase the impurity content of the ternary material, and the porous corrosion-resistant crucible could not be used continuously. At this time, the number of uses was the service life of the porous corrosion-resistant crucible, and the number of uses was recorded. The service life of the porous corrosion-resistant crucible of this embodiment was 47 times.

[0060] The picture of the porous corrosion-resistant crucible of this embodiment after 30 high-temperature heating and cooling experiments is as Figure 2 shown.

[0061] To better illustrate the effects of the embodiments of the present invention, Comparative Example 1 and Comparative Example 2 were compared with Example 1 above.

[0062] Comparative Example 1

[0063] In this comparative example, the pre-treated crucible obtained in step (2) of Example 1 was used as Comparative Sample 1, which was different from Example 1 in that the high-temperature treatment in step (3) was not carried out.

[0064] The performance of Comparative Sample 1 of this comparative example was tested. The test method was the same as that of Example 1. The service life of the pre-treated crucible of this Comparative Example 1 was 36 times, which was much less than the service life of the porous corrosion-resistant crucible of Example 1.

[0065] Comparative Example 2

[0066] In this comparative example, a conventional mullite-cordierite crucible without modification treatment, that is, the mullite-cordierite crucible in Example (2), was directly used as Comparative Sample 2.

[0067] The performance of Comparative Sample 2 of this comparative example was tested. The test method was the same as that of Example 1. The service life of the mullite-cordierite crucible of this Comparative Example 2 was 30 times, which was much less than the service life of the porous corrosion-resistant crucible of Example 1.

[0068] The picture of the conventional mullite-cordierite crucible of this comparative example after 30 high-temperature heating and cooling experiments is as Figure 2As shown, it can be seen that under the same firing times, the surface of the conventional mullite-cordierite saggers without modification treatment peels off seriously due to corrosion, while the surface of the porous corrosion-resistant saggers of Example 1 has no obvious peeling or flaking caused by corrosion. This is because, as can be seen, by coating two kinds of silicon carbide coatings with different particle sizes on the surface of the sagger and then subjecting them to high-temperature firing, a porous corrosion-resistant porous recrystallized silicon carbide layer is formed. On the one hand, the porous recrystallized silicon carbide layer isolates the direct contact between the precursor of the cathode material and the sagger, enhancing the corrosion resistance of the sagger. On the other hand, due to the rich porous morphology on the surface of the sagger of the present invention, the side reactions during the roasting process can all penetrate into the interior of the silicon carbide layer and react in the internal pores. The volume expansion effect accompanied by the side reactions can be dispersed to a deeper position, but it has little impact on the structure of the local material of the sagger, thereby improving the service life of the sagger.

[0069] Example 2

[0070] This example provides a porous corrosion-resistant sagger and its preparation method and application. The specific process is as follows:

[0071] (1) Put 1 kg of the first silicon carbide with D50 of 1.5 μm and 5 kg of the second silicon carbide with D50 of 10 μm into a high-speed mixer, with a rotation speed of 500 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0072] (2) Spray the silicon carbide mixed powder on the inner surface of the mullite-cordierite sagger to obtain a pretreated sagger.

[0073] (3) Place the pretreated sagger in a kiln furnace, and under vacuum conditions, heat it to 2380 °C and hold for 2 hours to obtain a porous corrosion-resistant sagger.

[0074] Perform performance tests on the porous corrosion-resistant sagger of this example. The test method is the same as that of Example 1. The service life of the pretreated sagger in this example is 42 times.

[0075] Example 3

[0076] This example provides a porous corrosion-resistant sagger and its preparation method and application. The specific process is as follows:

[0077] (1) Put 1 kg of the first silicon carbide with D50 of 2 μm and 5 kg of the second silicon carbide with D50 of 15 μm into a high-speed mixer, with a rotation speed of 600 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0078] (2) Spray the silicon carbide mixed powder on the inner surface of the mullite-cordierite sagger to obtain a pretreated sagger.

[0079] (3) Place the pretreated crucible in a kiln, and under vacuum conditions, heat it to 2450 °C and hold for 2 hours to obtain a porous corrosion-resistant crucible.

[0080] Perform performance tests on the porous corrosion-resistant crucible of this example. The test method is the same as that of Example 1. The service life of the pretreated crucible in this example is 45 times.

[0081] Example 4

[0082] This example provides a porous corrosion-resistant crucible, its preparation method and application. The specific process is as follows:

[0083] (1) Place 1 kg of the first silicon carbide with a D50 of 3.5 μm and 4 kg of the second silicon carbide with a D50 of 20 μm in a high-speed mixer, with a rotation speed of 450 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0084] (2) Extrusion-coat the silicon carbide mixed powder on the inner surface of a mullite-cordierite crucible to obtain a pretreated crucible.

[0085] (3) Place the pretreated crucible in a kiln, and under vacuum conditions, heat it to 2300 °C and hold for 4 hours to obtain a porous corrosion-resistant crucible.

[0086] Perform performance tests on the porous corrosion-resistant crucible of this example. The test method is the same as that of Example 1. The service life of the pretreated crucible in this example is 40 times.

[0087] Example 5

[0088] This example provides a porous corrosion-resistant crucible, its preparation method and application. The specific process is as follows:

[0089] (1) Place 1 kg of the first silicon carbide with a D50 of 3.5 μm and 8 kg of the second silicon carbide with a D50 of 10 μm in a high-speed mixer, with a rotation speed of 550 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0090] (2) Knife-coat the silicon carbide mixed powder on the inner surface of a mullite-cordierite crucible to obtain a pretreated crucible.

[0091] ] (3) Place the pretreated crucible in a kiln, and under vacuum conditions, heat it to 2350 °C and hold for 3.5 hours to obtain a porous corrosion-resistant crucible.

[0092] Perform performance tests on the porous corrosion-resistant crucible of this example. The test method is the same as that of Example 1. The service life of the pretreated crucible in this example is 41 times.

[0093] Example 6

[0094] This embodiment provides a porous corrosion-resistant crucible, its preparation method and application. The specific process is as follows:

[0095] (1) Place 1 kg of first silicon carbide with a D50 of 1.5 μm and 3 kg of second silicon carbide with a D50 of 20 μm in a high-speed mixer, rotate at 600 rpm, and mix evenly to obtain a silicon carbide mixed powder.

[0096] (2) Scraping and coating the silicon carbide mixed powder on the inner surface of a mullite-cordierite crucible to obtain a pretreated crucible.

[0097] (3) Place the pretreated crucible in a kiln furnace, under vacuum conditions, heat up to 2450 °C and hold for 3 hours to obtain a porous corrosion-resistant crucible.

[0098] Perform performance tests on the porous corrosion-resistant crucible of this embodiment. The test method is the same as that of Embodiment 1. The service life of the pretreated crucible in this embodiment is 43 times.

[0099] The above specific implementation manners further elaborate on the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above is only the specific implementation manner of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A porous corrosion-resistant sagger, characterized in that, The porous corrosion-resistant sagger includes a sagger body and a porous recrystallized silicon carbide layer attached to the inner surface of the sagger body; The porous recrystallized silicon carbide layer is formed by making slurries of two silicon carbides with different particle size ratios, coating the slurries on the surface of the sagger body layer, and then undergoing high-temperature recrystallization under vacuum or argon conditions; The silicon carbide content in the porous recrystallized silicon carbide layer is ≥99.4%, the pore size is 2μm - 20μm, and the porosity is 16% - 20%.

2. The porous corrosion-resistant sagger according to claim 1, characterized in that, The sagger body includes: a mullite-cordierite sagger; The thickness of the porous recrystallized silicon carbide layer is 2mm - 6mm.

3. The porous corrosion-resistant sagger according to claim 1, characterized in that, The two silicon carbides with different particle size ratios are respectively a first silicon carbide and a second silicon carbide; The particle size D50 of the first silicon carbide is between 1.5μm and 3.5μm; The particle size D50 of the second silicon carbide is between 10μm and 20μm; The mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:

8.

4. A method for preparing the porous corrosion-resistant crucible according to any one of claims 1-3 above, characterized in that, The preparation method includes: Placing the first silicon carbide and the second silicon carbide in a mixing device, mixing evenly to obtain a silicon carbide mixed powder; Coating the silicon carbide mixed powder on the inner surface of the sagger body to obtain a pretreated sagger; Placing the pretreated sagger in a kiln furnace, and under vacuum or argon conditions, through high-temperature treatment, enabling the silicon carbide mixed powder to undergo high-temperature recrystallization to form a porous recrystallized silicon carbide layer, thereby obtaining a porous corrosion-resistant sagger.

5. The preparation method according to claim 4, characterized in that, The particle size D50 of the first silicon carbide is between 1.5μm and 3.5μm; The particle size D50 of the second silicon carbide is between 10μm and 20μm; The mass ratio of the first silicon carbide to the second silicon carbide is 1:3 - 1:

8.

6. The preparation method according to claim 4, characterized in that, The mixing device includes: a high-speed mixer.

7. The preparation method according to claim 4, characterized in that, The sagger body is a mullite-cordierite sagger; The coating method includes one or more of spraying, extrusion coating, or scraping coating; The temperature of the high-temperature treatment is 2300°C - 2450°C, and the heat preservation time is 1 hour - 4 hours.

8. The preparation method according to claim 4, characterized in that, The thickness of the porous recrystallized silicon carbide layer is 2mm - 6mm, the silicon carbide content is ≥99.4%, the pore size is 2μm - 20μm, and the porosity is 16% - 20%.

9. Use of the porous corrosion-resistant sagger according to any one of claims 1-3 above, characterized in that, The porous corrosion-resistant sagger is used in the sintering treatment process for preparing the cathode material.

10. The application of the porous corrosion-resistant sagger according to claim 9, characterized in that, The cathode material includes a ternary cathode material or a lithium cobalt oxide cathode material.

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