A sagger, its manufacturing method and application

Abstract

This invention discloses a sagger, its preparation method, and its application, belonging to the field of ceramic technology. The sagger provided by this invention, through the selection of suitable raw materials and preparation methods, and the interaction between components, results in a sagger with a porosity of 4.4-5.9% and a coefficient of thermal expansion of 4.9 × 10⁻⁶. ‑6 -5.4×10 ‑6 With a shrinkage rate of 1.14-1.18% at ℃, it can be well applied to sintering single-crystal high-nickel ternary cathode materials, thereby improving the purity and yield of single-crystal high-nickel ternary cathode materials.

Description

Technical Field

[0001] This invention belongs to the field of ceramic technology, and in particular relates to a sagger and its preparation method. Background Technology

[0002] In recent years, single-crystal NCM materials (S-NCM) have been introduced as an alternative strategy to improve cycle stability. Compared with polycrystalline NCM (P-NCM) particles, single-crystal particles exhibit unidirectional contraction / expansion, which is a major advantage in reducing crack formation. S-NCM particles can be produced using polycrystalline Ni... 0.9 Co 0.05 Mn 0.05 (OH)₂ hydroxide precursor particles are co-precipitated and then calcined with LiOH·H₂O at a sintering temperature slightly higher than that of P-NCM to synthesize S-NCM. To avoid excessive particle aggregation, S-NCM particles are typically smaller than P-NCM particles. Due to the limited / free grain boundaries, smaller particles are less prone to crack formation. Thanks to its unique morphology, S-NCM outperforms polycrystalline materials with the same composition in several aspects. In terms of long-term cycling stability, no microcracks are generated on the surface or inside of S-NCM particles. In terms of high-voltage performance, there are fewer side reactions at the electrode / electrolyte interface, a high degree of reaction reversibility, and good capacity retention. In addition, S-NCM exhibits good compaction density and high volumetric energy density in practical applications. Particle size plays a crucial role in electrochemical reactions because smaller particle sizes result in better mechanical integrity and kinetics during charge-discharge cycles. However, due to harmful phase transitions, the impact of surface degradation also increases. The above description does not show a systematic study of the degradation / improvement mechanism of S-NCM, nor does it determine the mechanism of crack formation in S-NCM.

[0003] Single-crystal and polycrystalline LiNi 0.9 Co 0.05 Mn 0.05 The preparation process of O2 cathode material is as follows: Single-crystal and polycrystalline Ni are synthesized using the hydroxide co-precipitation method. 0.9 Co 0.05 Mn 0.05 (OH)₂ precursor. The obtained precursor was thoroughly mixed with an excess of 6% LiOH·H₂O, and the single-crystal precursor was calcined at 500℃ for 10 h (heating rate 5℃ / min) under an oxygen atmosphere, followed by calcination at 830℃ for 15 h to obtain the single-crystal cathode material LiNi. 0.9 Co 0.05 Mn 0.05 O2 (S-NCM). The production process for polycrystalline materials is basically the same as that for single-crystal materials, with only slight differences in sintering temperature. The first stage of sintering is carried out at 400℃ for 10 hours, and the second stage is carried out at 780℃ for 15 hours, yielding the polycrystalline cathode material LiNi. 0.9 Co0.05 Mn 0.05 O2(P-NCM).

[0004] In summary, the requirements for sintering single-crystal high-nickel ternary cathode materials are higher. Because the particle size of single-crystal high-nickel materials is smaller, the lower the porosity of the sintering sag, the better, as the single-crystal material is less likely to penetrate into the sag. The sintering temperature of single-crystal precursors is higher than that of polycrystalline precursors, which places higher requirements on the corrosion resistance and temperature resistance of the sag. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a sagger with low porosity, low coefficient of thermal expansion and low shrinkage, as well as its preparation method and application.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a sagger having a porosity of 4.4-5.9% and a coefficient of thermal expansion of 4.9 × 10⁻⁶. -6 -5.4×10 -6 / ℃, shrinkage rate is 1.14-1.18%.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0008] The sagger provided by this invention has low porosity, low coefficient of thermal expansion, and low shrinkage, thus enabling it to be well applied to the sintering of single-crystal high-nickel ternary cathode materials. Specifically, the low porosity of the sagger can prevent single-crystal material from penetrating into the sagger; the low coefficient of thermal expansion of the sagger allows the sagger to withstand higher temperatures, which is beneficial for the sintering of single-crystal materials and significantly improves the service life of the sagger; the low shrinkage of the sagger can stabilize the size of the sagger, thereby stabilizing the sintering process of single-crystal materials and improving the overall performance of the single-crystal materials obtained after sintering. Detailed Implementation

[0009] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0010] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in the field; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0011] In a first aspect, the present invention provides a sagger having a porosity of 4.4-5.9% and a coefficient of thermal expansion of 4.9 × 10⁻⁶. -6 -5.4×10 -6 / ℃, shrinkage rate 1.14-1.18%.

[0012] It should be noted that the porosity of the crucible is tested by the vacuum method. Specifically, the dry weight of the sample is first weighed, then the crucible sample is placed in a container separated by a wire frame, placed in a vacuum device, and vacuumed for 10 minutes at a vacuum degree of not less than 0.095 MPa. Distilled water is then added until the liquid level exceeds the sample by (20±5) mm. The vacuum degree is maintained at not less than 0.095 MPa for 30 minutes. The vacuum device is then opened, the sample is removed, and excess liquid on the sample surface is gently wiped away with a cotton towel soaked in distilled water. The wet weight is then weighed, and finally the buoyant weight is weighed. The porosity is then calculated using the formula.

[0013] It should be noted that the coefficient of thermal expansion of the sagger is tested using a thermal expansion tester. Specifically, the sagger sample is subjected to a certain temperature program and a load force close to zero, and the dimensional change of the sample is measured as a function of temperature or time.

[0014] It should be noted that the shrinkage rate of the sagger is calculated by measuring the dimensions of the sagger sample during greening and after sintering.

[0015] For example, the porosity of the sagger can be any point value or any two-point range between 4.4% and 5.9%, such as 4.4%, 4.6%, 4.8%, 5%, 5.2%, 5.4%, 5.6%, 5.8%, 5.9%, etc.

[0016] For example, the coefficient of thermal expansion of the sagger can be 4.9 × 10⁻⁶. -6 -5.4×10 -6 Any point value or any range between two points between / ℃, for example, 4.9 x 10 -6 / ℃, 5x10 -6 / ℃, 5.1x10 -6 / ℃, 5.2x10 -6 / ℃, 5.3x10 -6 / ℃, 5.4x10 -6 / ℃, etc.

[0017] For example, the shrinkage rate of the sagger can be any point value or any two-point range value between 1.14% and 1.18%, such as 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, etc.

[0018] In some embodiments, the raw materials for preparing the sagger include the following components in parts by weight: 53-63 parts cordierite, 10-15 parts magnesium aluminum spinel, 10-15 parts zirconium silicate, 8-12 parts alumina, 0.5-1.5 parts zirconium oxide, 0.5-1.5 parts titanium oxide, and 5-10 parts corundum powder.

[0019] The present invention has found that when the raw materials for saggers provided by the present invention are used, the raw materials interact and cooperate with each other, which can effectively reduce the porosity, thermal expansion coefficient and shrinkage rate of the sagger.

[0020] Specifically, firstly, the zirconium silicate, alumina, and corundum powder selected in the raw materials of this invention can effectively resist the erosion of the sagger during the subsequent sintering of single-crystal high-nickel ternary cathode material, thus effectively improving the sagger's erosion resistance and stability. Secondly, the simultaneous use of cordierite and corundum powder as raw materials, combined with other components, can effectively reduce the thermal expansion coefficient of the sagger, which is beneficial for extending the sagger's service life. Thirdly, the selection of appropriate mass proportions of zirconium oxide and alumina, after high-temperature sintering, results in an aluminum-zirconium toughening phase, which can further form an aluminum-zirconium-silicon composite ceramic with zirconium silicate, further enhancing the sagger's toughness and erosion resistance.

[0021] In some embodiments, the average particle size of the cordierite is 200-300 mesh.

[0022] For example, the average particle size of the cordierite can be any point value or any two points between 200 and 300 mesh, such as 200 mesh, 250 mesh, 300 mesh, etc.

[0023] In some embodiments, the average grain size of the magnesium aluminum spinel is 200-300 mesh.

[0024] For example, the average grain size of the magnesium aluminum spinel can be any point value or any two points between 200 and 300 mesh, such as 200 mesh, 250 mesh, 300 mesh, etc.

[0025] In some embodiments, the zirconium silicate has a Dv50 particle size of 1-3 μm and a particle size distribution range of 0.1-4 μm.

[0026] For example, the Dv50 particle size of the zirconium silicate can be any point value or any two-point range value between 1 and 3 μm, such as 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, etc.; the particle size distribution range can be any point value or any two-point range value between 0.1 and 16 μm, such as 0.1-15 μm, 0.2-16 μm, 0.3-16 μm, etc.

[0027] In some embodiments, the alumina has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-12 μm.

[0028] For example, the Dv50 particle size of the alumina can be any point value or any two-point range between 0.5-1.5μm, such as 0.5μm, 1μm, 1.5μm, etc.; the particle size distribution range can be any point value or any two-point range between 0.1-12μm, such as 0.1-12μm, 0.2-11μm, 0.4-10μm, etc.

[0029] In some embodiments, the zirconium oxide has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-14 μm.

[0030] For example, the Dv50 particle size of the zirconium oxide can be any point value or any two-point range between 0.5-1.5 μm, such as 0.5 μm, 1 μm, 1.5 μm, etc.; the particle size distribution range can be any point value or any two-point range between 0.1-14 μm, such as 0.1-13 μm, 0.3-14 μm, 0.4-11 μm, etc.

[0031] In some embodiments, the titanium oxide has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-15 μm.

[0032] For example, the Dv50 particle size of the titanium oxide can be any point value or any two-point range value between 0.5-1.5μm, such as 0.5μm, 1μm, 1.5μm, etc.; the particle size distribution range can be any point value or any two-point range value between 0.1-15μm, such as 0.2-14μm, 0.1-11μm, 0.1-15μm, etc.

[0033] In some embodiments, the alumina is α-alumina.

[0034] This invention has found that α-alumina has good stability and corrosion resistance, which helps to resist the erosion of single-crystal high-nickel materials and improves the stability of the crucible.

[0035] In some embodiments, the average particle size of the corundum powder is 200-300 mesh.

[0036] For example, the average particle size of the corundum powder can be any point value or any two-point range value between 200 and 300 mesh, such as 200 mesh, 250 mesh, 300 mesh, etc.

[0037] In some embodiments, the corundum powder is in the form of plates.

[0038] The present invention has discovered that a large number of tiny pores are distributed around the tabular corundum, and the pores are of moderate size and evenly distributed. These pores can effectively disperse thermal stress and reduce the damage caused by thermal stress. Therefore, they can improve the thermal stability of the product. In the process of sintering in the sagger, they work synergistically with cordierite to effectively reduce the thermal expansion coefficient of the sagger.

[0039] In some embodiments, the sagger is prepared by the following method:

[0040] The raw materials are mixed and then ball-milled with oleic acid to obtain a primary premix.

[0041] Add the water-based binder to the primary premix and mix to obtain the secondary premix;

[0042] The secondary premix is ​​mixed with a polyol to obtain a tertiary premix;

[0043] The three premixes are aged;

[0044] After aging, the process involves dry pressing, green body processing, low-temperature debinding, and high-temperature sintering followed by cooling.

[0045] The present invention has found that by first dry-mixing the raw materials and then adding oleic acid, the raw materials can be mixed more evenly, which is more conducive to subsequent dry pressing, green body processing, low-temperature debinding and high-temperature sintering. In addition, the addition of water-based binders can also improve subsequent dry pressing, green body processing, low-temperature debinding and high-temperature sintering.

[0046] In some implementations, the oleic acid content is 0.5-2% by mass, based on the total mass of the crucible material.

[0047] For example, the mass percentage of oleic acid, based on the total mass of the raw materials in the sagger, can be any point value or any two-point range between 0.5% and 2%, such as 0.5%, 1%, 1.5%, 2%, etc.

[0048] In some implementations, the water-based binder comprises 9-13% by mass of the total mass of the crucible material.

[0049] For example, the mass percentage of the water-based binder, based on the total mass of the crucible material, can be any point value or any two-point range value between 9% and 13%, such as 9%, 10%, 11%, 12%, 13%, etc.

[0050] In some embodiments, the mass percentage of polyol is 0.1-1% based on the total mass of the sagger raw materials.

[0051] For example, the mass percentage of polyol based on the total mass of the raw materials in the sagger can be any point value or any two-point range value between 0.1% and 1%, such as 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, etc.

[0052] In some embodiments, the oleic acid includes at least one of animal oleic acid and vegetable oleic acid.

[0053] In some embodiments, the water-based binder includes at least one of carboxymethyl cellulose and dextrin.

[0054] In some embodiments, the polyol includes at least one of glycerol, sorbitol, and propylene glycol.

[0055] In some embodiments, the ball milling ratio is (0.5-2):1, and the milling time is 3-9 hours.

[0056] In some embodiments, the mixing time is 2-5 hours.

[0057] In some embodiments, the aging time is 10-14 hours and the aging temperature is 20-30°C.

[0058] In some embodiments, the pressure of the dry pressing is 80-120 MPa.

[0059] In some embodiments, the low-temperature debinding is performed by raising the temperature from 20-30°C to 200-240°C over 20-30 hours, holding the temperature for 1-3 hours, and then cooling it back to 20-30°C.

[0060] In some embodiments, the high-temperature sintering temperature is 1370-1420°C, and the high-temperature sintering time is 1-3 hours.

[0061] For example, the high-temperature sintering temperature can be any point value or any two-point range between 1370-1420℃, such as 1370℃, 1380℃, 1390℃, 1400℃, 1410℃, 1420℃, etc.; the high-temperature sintering time can be any point value or any two-point range between 1-3h, such as 1h, 2h, 3h, etc.

[0062] This invention has discovered that high-temperature sintering involves solid-state reactions. Under the high-temperature sintering temperature and time provided by this invention, a relatively high sintering driving force can be provided. The titanium dioxide sintering aid in the raw materials can increase lattice vacancies, facilitate diffusion, accelerate the sintering rate, promote the bonding of solid particles in the raw materials, and promote grain growth. The porosity and grain boundaries in the green body gradually decrease, the green body gradually shrinks, and the density slowly increases; thus, a sagger with low porosity, coefficient of thermal expansion, and shrinkage rate is obtained.

[0063] In some implementations, the temperature rise procedure for high-temperature sintering is as follows:

[0064] Starting at 20-30℃, increase the temperature to 220±5℃ at a rate of 2±0.2℃ / min. Then, increase the temperature from 220±5℃ to 300±5℃ at a rate of 1±0.2℃ / min and hold for 0.5±0.1h. Next, increase the temperature from 300±5℃ to 500±5℃ at a rate of 1±0.2℃ / min and hold for 0.5±0.1h. Then, increase the temperature from 500±5℃ to 600±5℃ at a rate of 1±0.2℃ / min and hold for 0.5±0.1h. Then... Heat the temperature at a rate of 2±0.2℃ / min from 600±5℃ to 900±5℃ and hold for 0.5±0.1h. Then heat the temperature at a rate of 2±0.2℃ / min from 900±5℃ to 1050±5℃ and hold for 0.5±0.1h. Next, heat the temperature at a rate of 2±0.2℃ / min from 1050±5℃ to 1250±5℃ and hold for 0.5±0.1h. Finally, heat the temperature at a rate of 0.5±0.2℃ / min to 1370-1420℃ and hold for 1-3h.

[0065] In some embodiments, the sagger is a one-piece sagger.

[0066] The sagger provided by this invention can be manufactured in a one-piece form, which can effectively avoid the problem of existing layered saggers where the layers separate during use due to the different thermal expansion coefficients of each layer. After separation, the layers are easy to fall into the sintered battery material, affecting the purity of the battery material. At the same time, the one-piece sagger provided by this invention is more compact and has higher stability.

[0067] In a second aspect, the present invention provides a method for preparing a sagger, the method comprising the following steps:

[0068] S1. Mix 53-63 parts cordierite, 10-15 parts magnesium aluminum spinel, 10-15 parts zirconium silicate, 8-12 parts alumina, 0.5-1.5 parts zirconium oxide, 0.5-1.5 parts titanium oxide, and 5-10 parts corundum powder to obtain a mixed raw material.

[0069] S2. Add oleic acid to the mixed raw materials, mix evenly, and then ball mill to obtain a primary premix.

[0070] S3. The primary premix is ​​mixed with the water-based adhesive to obtain the secondary premix;

[0071] S4. The secondary premix is ​​mixed with a polyol to obtain a tertiary premix;

[0072] S5. The three premixed materials are aged sequentially, and after aging, they are successively subjected to dry pressing, green body processing, low-temperature debinding, high-temperature sintering, and cooling to obtain the sagger.

[0073] In some implementations, the oleic acid content is 0.5-2% by mass, based on the total mass of the crucible material.

[0074] In some implementations, the water-based binder comprises 9-13% by mass of the total mass of the crucible material.

[0075] In some embodiments, the mass percentage of polyol is 0.1-1% based on the total mass of the sagger raw materials.

[0076] In some embodiments, the oleic acid includes at least one of animal oleic acid and vegetable oleic acid.

[0077] In some embodiments, the water-based binder includes at least one of carboxymethyl cellulose and dextrin.

[0078] In some embodiments, the polyol includes at least one of glycerol, sorbitol, and propylene glycol.

[0079] In some embodiments, the ball milling ratio is (0.5-2):1, and the milling time is 3-9 hours.

[0080] In some embodiments, the mixing time is 2-5 hours.

[0081] In some embodiments, the mixing is performed in a biaxial blade mixer.

[0082] In some embodiments, the aging time is 10-14 hours and the aging temperature is 20-30°C.

[0083] In some embodiments, the pressure of the dry pressing is 80-120 MPa.

[0084] In some embodiments, the dry pressing is performed in a static pressure mold.

[0085] In some implementations, the green blank is processed by: grinding the bottom of the green blank after dry pressing with a carving machine and cutting the opening of the green blank flat.

[0086] In some embodiments, the low-temperature debinding is performed by raising the temperature from 20-30°C to 200-240°C over 20-30 hours, holding the temperature for 1-3 hours, and then cooling it back to 20-30°C.

[0087] In some embodiments, the high-temperature sintering temperature is 1370-1420°C, and the high-temperature sintering time is 1-3 hours.

[0088] In some implementations, high-temperature sintering is performed in a silicon carbide rod electric furnace.

[0089] In a third aspect, the present invention provides the application of the sagger in the sintering preparation of single-crystal high-nickel ternary cathode materials.

[0090] The sagger provided by this invention has low porosity, low coefficient of thermal expansion, low shrinkage, and strong corrosion resistance. It can be effectively applied to the sintering of single-crystal high-nickel ternary cathode materials to improve the purity and yield of single-crystal high-nickel ternary cathode materials.

[0091] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0092] The sagger provided by this invention, through the selection of appropriate raw materials and preparation methods, and the interaction between components, results in a sagger with low porosity, low coefficient of thermal expansion, and low shrinkage. This allows it to be well applied to sintering single-crystal high-nickel ternary cathode materials, thereby improving the purity and yield of single-crystal high-nickel ternary cathode materials.

[0093] Example 1

[0094] This invention provides a sagger, the preparation method of which includes the following steps:

[0095] S1. Mix 63 parts cordierite (250 mesh), 10 parts magnesium aluminum spinel (200 mesh), 10 parts zirconium silicate (Dv50 particle size 2μm, particle size distribution range 0.1-16μm), 10 parts alumina (Dv50 particle size 1μm, particle size distribution range 0.1-12μm), 1 part zirconium oxide (Dv50 particle size 1μm, particle size distribution range 0.1-14μm), 1 part titanium oxide (Dv50 particle size 1μm, particle size distribution range 0.1-16μm), and 5 parts corundum powder (300 mesh) in a ball mill to obtain a mixed raw material;

[0096] S2. Add animal oleic acid (0.5% by mass based on the total mass of the raw materials) to the mixed raw materials, mix evenly, and then ball mill at a material-to-ball ratio of 2:1 for 6 hours to obtain a premix.

[0097] S3. Place the primary premix into a twin-blade mixer. While the mixer is rotating, slowly add the water-based binder (11% by mass of the total raw materials, including carboxymethyl cellulose and dextrin in a 1:1 mass ratio) using a pressure vessel. Keep stirring during this process to prevent agglomeration, and obtain the secondary premix.

[0098] S4. Add glycerol (0.1% by mass of water-based binder based on the total mass of raw materials) to the secondary premix and mix for 3 hours. After mixing, put the mixture into a sealed stainless steel storage tank and age it at 25°C for 12 hours.

[0099] S5. Place the aged mixture into an isostatic pressing mold, vibrate it, and then use an isostatic press to press the mixture into a green body. The forming pressure during dry pressing is 120 MPa to obtain the green body.

[0100] S6. Process the obtained green blank by grinding the bottom of the green blank flat with a carving machine and cutting the opening of the green blank flat to process it into a pre-fired blank.

[0101] S7. Perform low-temperature debinding on the pre-fired blanks, arrange the blanks neatly and put them into the oven. After 30 hours, raise the temperature from 25℃ to 220℃ and keep it at that temperature for 2 hours, then let it cool naturally to room temperature.

[0102] S8. The blank obtained after low-temperature debinding is sintered at high temperature. The high-temperature sintering is carried out in a silicon carbide rod electric furnace, heated to 1410℃ and held for 1.5h, and then naturally cooled to room temperature to obtain a sagger.

[0103] The process of raising the temperature from 25℃ to 220℃ over 30 hours is as follows: starting from 25℃, the temperature is increased at a rate of 2℃ / min to 220℃, then increased at a rate of 1℃ / min from 220℃ to 300℃ and held for 0.5 hours, then increased at a rate of 1℃ / min from 300℃ to 500℃ and held for 0.5 hours, then increased at a rate of 1℃ / min from 500℃ to 600℃ and held for 0.5 hours, then increased at a rate of 2℃ / min from 600℃ to 900℃ and held for 0.5 hours, then increased at a rate of 2℃ / min from 900℃ to 1050℃ and held for 0.5 hours, then increased at a rate of 2℃ / min from 1050℃ to 1250℃ and held for 0.5 hours, and finally increased at a rate of 0.5℃ / min from 1250℃ to 1410℃ and held for 1.5 hours.

[0104] Example 2

[0105] This invention provides a sagger, the only difference between the sagger and that of Example 1 is in step S1, where 53 parts of cordierite (250 mesh), 15 parts of magnesium aluminum spinel (200 mesh), 10 parts of zirconium silicate (Dv50 particle size of 1 μm, particle size distribution range of 0.1-16 μm), 10 parts of alumina (Dv50 particle size of 1.5 μm, particle size distribution range of 0.1-12 μm), 1 part of zirconium oxide (Dv50 particle size of 0.5 μm, particle size distribution range of 0.1-14 μm), 1 part of titanium oxide (Dv50 particle size of 1 μm, particle size distribution range of 0.1-15 μm), and 10 parts of corundum powder (300 mesh) are mixed and placed in a ball mill to obtain a mixed raw material.

[0106] Example 3

[0107] This invention provides a sagger, the only difference between the sagger and that of Example 1 is in step S1, where 53 parts of cordierite (200 mesh), 15 parts of magnesium aluminum spinel (300 mesh), 15 parts of zirconium silicate (Dv50 particle size of 3 μm, particle size distribution range of 0.1-16 μm), 10 parts of alumina (Dv50 particle size of 0.5 μm, particle size distribution range of 0.1-12 μm), 1 part of zirconium oxide (Dv50 particle size of 1.5 μm, particle size distribution range of 0.1-14 μm), 1 part of titanium oxide (Dv50 particle size of 1 μm, particle size distribution range of 0.1-15 μm), and 5 parts of corundum powder (200 mesh) are mixed and placed in a ball mill to obtain a mixed raw material.

[0108] Example 4

[0109] This invention provides a sagger, the only difference between the sagger and that of Example 1 is that, based on the total mass of the sagger raw materials, the mass percentage of animal oleic acid is 2%, the mass percentage of water-based binder is 11%, and the mass percentage of glycerol is 1%.

[0110] Example 5

[0111] This invention provides a sagger, the only difference between the sagger and that of Embodiment 1 is that the forming pressure during dry pressing in step S5 is 80 MPa.

[0112] Example 6

[0113] This invention provides a sagger, the only difference between the sagger and that of Embodiment 1 is that in step S7, the temperature is raised from 25°C to 240°C over 20 hours and held for 1 hour, and then naturally cooled to room temperature.

[0114] Example 7

[0115] This invention provides a sagger, the only difference between the sagger and that in embodiment 1 is that in step S8, the temperature is heated to 1400°C and held for 3 hours.

[0116] Comparative Example 1

[0117] The present invention provides a sagger as a comparative example. The only difference between the sagger and Example 1 is that corundum powder is not added, and its amount is made up with alumina.

[0118] Comparative Example 2

[0119] The present invention provides a sagger as a comparative example. The only difference between the sagger and Example 1 is that zirconium silicate is not added, and its amount is made up with zirconium oxide.

[0120] Comparative Example 3

[0121] The present invention provides a sagger as a comparative example. The only difference between the sagger and Example 1 is that alumina is not added, and its amount is made up with corundum powder.

[0122] Comparative Example 4

[0123] The present invention provides a sagger, the only difference between the sagger and Example 1 is that kaolin is used instead of corundum powder.

[0124] Example of effect

[0125] 1. The performance of the saggers prepared in Examples 1-7 and Comparative Examples 1-4 is verified by the following aspects: Porosity: obtained by vacuum test, specifically: first weigh the dry weight of the sample block, then put the sagger sample block into a container separated by a wire frame, place it in a vacuum device, vacuum for 10 minutes at a vacuum degree of not less than 0.095 MPa, add distilled water until the liquid level exceeds the sample by (20±5) mm, maintain at a vacuum degree of not less than 0.095 MPa for 30 minutes, open the vacuum device, take out the sample, gently wipe away the excess liquid on the sample surface with a cotton towel saturated with distilled water, weigh its wet weight; finally weigh its buoyant weight; calculate the porosity using the formula.

[0126] 2. Shrinkage rate: Obtained by measuring the dimensions before and after high-temperature sintering.

[0127] 3. Coefficient of thermal expansion: This is obtained by testing with a thermal expansion tester. Specifically, it involves measuring the dimensional change of a sagger sample as a function of temperature or time under a certain temperature program and a load force close to zero.

[0128] The test results are shown in Table 1.

[0129] Table 1

[0130]

[0131] As can be seen from Table 1, when the technical solution provided by this invention is adopted, the resulting sagger has excellent comprehensive performance; specifically, the porosity of the resulting sagger is below 5.86%, the shrinkage rate is below 1.18%, and the coefficient of thermal expansion is below 5.35 × 10⁻⁶. -6 / ℃ below;

[0132] As can be seen from Examples 1 and Comparative Examples 1-4, when any component of the raw material used to prepare the sagger is missing or replaced by other components, the overall performance of the sagger decreases significantly. Specifically, when corundum powder is not added in Comparative Example 1 and alumina is used to supplement it, the coefficient of thermal expansion of the product increases significantly. When zirconium silicate is not added in Comparative Example 2 and zirconium oxide is used to supplement it, the coefficient of thermal expansion of the product also increases significantly. When corundum powder is used to supplement it without alumina in Comparative Example 3, the porosity of the product increases significantly, and the coefficient of thermal expansion also shows a certain increasing trend. When kaolin is used to replace corundum powder in Comparative Example 4, the shrinkage rate of the product shows a significant increasing trend, and the coefficient of thermal expansion also increases to a certain extent.

[0133] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A sagger, characterized by, The porosity of the said saggar is 4.4-5.9%, the thermal expansion coefficient is 4.9x10 -6 -5.4x10 -6 -1.14-1.18%.

2. The sagger of claim 1, wherein, The raw materials for preparing the sagger include the following components in parts by weight: 53-63 parts cordierite, 10-15 parts magnesium aluminum spinel, 10-15 parts zirconium silicate, 8-12 parts alumina, 0.5-1.5 parts zirconium oxide, 0.5-1.5 parts titanium oxide, and 5-10 parts corundum powder.

3. The sagger according to claim 2, characterized in that, The average grain size of the cordierite is 200-300 mesh; and / or, The average grain size of the magnesium aluminum spinel is 200-300 mesh; and / or, The zirconium silicate has a Dv50 particle size of 1-3 μm and a particle size distribution range of 0.1-16 μm; and / or, The alumina has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-12 μm; and / or, The zirconium oxide has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-14 μm; and / or, The titanium oxide has a Dv50 particle size of 0.5-1.5 μm and a particle size distribution range of 0.1-15 μm; and / or, The average particle size of the corundum powder is 200-300 mesh.

4. The sagger of claim 2, wherein, The sagger is prepared by the following method: The raw materials are mixed and then ball-milled with oleic acid to obtain a primary premix. Add the water-based binder to the primary premix and mix to obtain the secondary premix; The secondary premix is ​​mixed with a polyol to obtain a tertiary premix; The three premixes are aged; After aging, the process involves dry pressing, green body processing, low-temperature debinding, and high-temperature sintering followed by cooling.

5. The sagger according to claim 4, characterized in that, The mass percentage of oleic acid is 0.5-2% based on the total mass of the raw materials in the sagger. And / or, based on the total mass of the crucible material, the water-based binder comprises 9-13% by mass; And / or, based on the total mass of the sagger raw materials, the mass percentage of polyol is 0.1-1%.

6. The sagger according to claim 4, characterized in that, The oleic acid includes at least one of animal oleic acid and vegetable oleic acid; And / or, the water-based binder includes at least one of carboxymethyl cellulose and dextrin; And / or, the polyol includes at least one of glycerol, sorbitol, and propylene glycol.

7. The sagger according to claim 4, characterized in that, The ball milling process has a material-to-ball ratio of (0.5-2):1, and the milling time is 3-9 hours. And / or, the mixing time is 2-5 hours.

8. The sagger according to claim 4, characterized in that, The aging time is 10-14 hours, and the aging temperature is 20-30℃; And / or, the pressure of the dry pressing is 80-120 MPa; And / or, the low-temperature debinding is: after 20-30h the temperature is raised from 20-30℃ to 200-240℃, the temperature is held for 1-3h, and then cooled to 20-30℃; And / or, the high-temperature sintering temperature is 1370-1420℃, and the high-temperature sintering time is 1-3h.

9. A method for preparing a sagger, characterized in that, The preparation method includes the following steps: S1. Mix 53-63 parts cordierite, 10-15 parts magnesium aluminum spinel, 10-15 parts zirconium silicate, 8-12 parts alumina, 0.5-1.5 parts zirconium oxide, 0.5-1.5 parts titanium oxide, and 5-10 parts corundum powder to obtain a mixed raw material. S2. After the mixed raw materials and oleic acid are mixed evenly, the mixture is ball-milled to obtain a primary premix. S3. The primary premix is ​​mixed with the water-based adhesive to obtain the secondary premix; S4. The secondary premix is ​​mixed with a polyol to obtain a tertiary premix; S5. The three premixed materials are aged sequentially, and after aging, they are successively subjected to dry pressing, green body processing, low-temperature debinding, high-temperature sintering, and cooling to obtain the sagger.

10. The application of the sagger as described in any one of claims 1-8 in the sintering preparation of single-crystal high-nickel ternary cathode materials.

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