A crucible for sintering high-nickel NCM811 series ternary cathode materials and a preparation method thereof

Abstract

The present invention discloses a sagger for sintering high-nickel NCM811 series ternary cathode materials and a preparation method thereof. The specific steps of the preparation method are as follows: S1. Mix fused zirconia spinel particles, fused zirconia spinel fine powder, rare earth composite yttrium zirconium ceramic powder and zirconium boride fine powder to obtain a premix; S2. Sequentially add lime milk and zirconia sol to the premix to obtain a mixture; S3. Cast and vibrate the mixture to form, cure and demold to obtain a green body; S4. Dry and heat-treat the green body and then cool it to room temperature to obtain a sagger for sintering high-nickel NCM811 series ternary cathode materials. The process of the present invention is simple, the sintering temperature is low, no other impurity components are introduced, and the sagger for sintering high-nickel NCM811 series ternary cathode materials prepared has good sintering performance, high strength, high thermal shock stability and strong erosion and penetration resistance to lithium-nickel components.

Description

Technical Field

[0001] The present invention relates to the technical field of saggers, and particularly to a sagger for sintering high-nickel NCM811 series ternary cathode materials and a preparation method thereof. Background Art

[0002] A sagger is an important container and functional carrier during the calcination process of the high-temperature solid-phase process of lithium-ion battery cathode materials. Its main function is to carry the cathode materials without causing pollution. During the reciprocating service process, the sagger is continuously eroded by the dual action of the cathode material precursor and the strong alkaline lithium source. Coupled with the action of cyclic thermal stress, it is extremely easy to cause cracking and structural spalling of the sagger, resulting in the damage of the sagger and the pollution of the cathode materials.

[0003] Different from other cathode materials, the high-nickel NCM811 series ternary cathode materials are based on Ni 0.8 Co 0.1 Mn 0.1 (OH)2 series as the precursor, lithium hydroxide (or lithium hydroxide monohydrate) as the lithium source, and other components are added and mixed and then calcined ( Subo Tao, Zhong Shengwen. Preparation and modification research of high energy density NCM811 ternary cathode materials [J]. Battery Industry, 2022, 26 (5):217-222 ). The characteristics of such ternary cathode materials are high specific capacity. And due to the composition of high nickel and low cobalt (even ultra-high nickel 9 series), the cobalt content is greatly reduced, and its price is relatively low and environmentally friendly. But for the sagger:

[0004] (1) Using lithium hydroxide as the lithium source, compared with the cathode materials using lithium carbonate as the lithium source, its alkalinity is stronger, and the erosion of the sagger is more serious.

[0005] (2) The high-nickel NCM811 series precursor has a high residual alkali content, and the alkalinity is further increased, resulting in increased erosion of the sagger.

[0006] (3) The relatively high nickel content leads to an increase in the penetration and diffusion of the ternary cathode material into the sagger, which also causes damage to the structure of the sagger.

[0007] At present, there are few reports on the special saggers for sintering high-nickel NCM811 series ternary cathode materials. Most of them continue to use cordierite-mullite, cordierite-spinel, and cordierite-corundum saggers for calcining ordinary lithium-ion battery cathode materials. However, cordierite or mullite saggers are easily damaged because they contain acidic SiO2 components, which are extremely easy to react with strong alkaline lithium sources to form lithium silicate or lithium nepheline and other phases. In corundum saggers, the Al2O3 component is also easy to react with the lithium source to form LiAlO2 (thermal expansion coefficient about 17×10 -6 / °C) and an aluminum-nickel spinel solid solution ( Zhai Pengtao, Liu Mingyang, Zhou Wenying, etc. Magnesium aluminate spinel on calcination LiNi x Co y Mn z Influence of the properties of the sagger materials for LiNi x Co y Mn z O2 cathode materials [J]. Refractories, 2021, 55(2): 102-106) This causes cracking of the saggers. In short, traditional saggers containing SiO2 and Al2O3 components can no longer adapt to the sintering of high-nickel NCM811 series ternary cathode materials.

[0008] In fact, relevant research work has also noticed the above problems and optimized the mullite saggers for sintering ternary cathode materials, achieving certain effects. However, its main drawback is that it can only be applied to medium / low-nickel series ternary cathode materials with NCM5 series (Ni 0.5 Co 0.2 Mn 0.3 (OH)2) as the precursor, and the lithium source is lithium carbonate ( Duan Jianjian, Shen Hongfang, Ma Congcong, etc. Cathode material LiNi of lithium battery x Co y Mn z Development of mullite-cordierite crucible for sintering of O2[J]. Bulletin of the Chinese Ceramic Society, 2023, 42(10)：3769-3777 ). Its erosion degree on the saggers and the solid-phase reaction rate (aluminum-nickel spinel solid solution) are much weaker than those of NCM8 series ternary cathode materials. In addition, some researchers have carried out coating by adding leucite ( Yin Yiming. Influence of adding nepheline on the performance of crucibles for ternary lithium battery cathode materials [D]. Henan: Zhengzhou University, 2018 ) and other means to improve the alkali erosion resistance of the saggers. However, the coating process is complex, and aluminum-silicon components are still inevitably introduced in components such as leucite, and the effect on solving the service performance of the saggers is still limited.

[0009] The patent "A Saggar for Sintering High-Nickel Ternary Materials and Its Preparation Method, CN201910190695.7" reports a method for preparing a saggar for sintering high-nickel ternary materials by spraying a coating. Its main technical means is to spray a composite coating with a thickness of 0.2 - 2 mm on the inner wall of the saggar matrix, so as to increase the number of uses of the saggar. Such technical means are simple to operate and the process is convenient. However, the composite coating and the material of the saggar matrix are different, and it is inevitable to fall off under the action of cyclic service thermal stress and erosion of the saggar. On the one hand, it affects the cathode material. On the other hand, when the coating falls off, the saggar faces the risk of instantaneous breakdown and failure, which is not conducive to the continuity and stability of the production of the cathode material. Summary of the Invention

[0010] The purpose of the present invention is to propose a saggar for sintering high-nickel NCM811 series ternary cathode materials and its preparation method in view of the above deficiencies of the prior art. This method has a simple process, a low sintering temperature, does not introduce other impurity components, and the prepared saggar for sintering high-nickel NCM811 series ternary cathode materials has good sintering performance, high strength, high thermal shock stability, and strong erosion and penetration resistance to lithium-nickel components.

[0011] The preparation method of a saggar for sintering high-nickel NCM811 series ternary cathode materials of the present invention is specifically as follows:

[0012] S1. Mix fused zirconia spinel particles, fused zirconia spinel fine powder, rare earth composite yttrium zirconia ceramic powder, and zirconium boride fine powder to obtain a premix;

[0013] S2. Add lime milk and zirconia sol to the premix in sequence to obtain a mixture.

[0014] S3. Cast and vibrate the mixture into shape, cure it, and demold it to obtain a green body.

[0015] S4. Dry and heat-treat the green body and then cool it to room temperature to obtain a sagger for sintering high-nickel NCM811 series ternary cathode materials.

[0016] Further, the mass ratio of fused zirconia spinel particles : fused zirconia spinel fine powder : rare earth composite yttrium zirconium ceramic powder : zirconium boride fine powder is 100 : (42 - 57) : (6 - 14) : (4 - 8).

[0017] Further, the lime milk is prepared from water and calcium hydroxide fine powder with a particle size ≤ 20 μm, and the mass ratio of water to calcium hydroxide fine powder is (2 - 3) : 1.

[0018] Further, the lime milk accounts for 2 - 4 wt% of the premix.

[0019] Further, the solid content of the zirconia sol is 25 - 30 wt%; the zirconia sol accounts for 4 - 6 wt% of the premix.

[0020] Further, in step S4, the green body is dried at 100 - 110 °C for 5 - 6 hours.

[0021] Further, in step S4, the heat treatment is carried out at 1315 - 1355 °C for 4 - 6 hours.

[0022] Further, the particle size of the fused zirconia spinel particles is 0.5 - 2.5 mm, and the mass ratio of the particles in the range of [0.5 - 1.0 mm], (1.0 - 1.5 mm], and (1.5 - 2.5 mm] is (10 - 15) : (10 - 15) : (60 - 65); in the chemical composition of the fused zirconia spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is (10 - 15) : (50 - 55) : (20 - 30); the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%; and / or

[0023] The particle size of the fused zirconia spinel fine powder is 40 - 45 μm; the mass ratio of ZrO2, MgO, and Al2O3 is (10 - 15) : (50 - 55) : (20 - 30); the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%.

[0024] Further, the grade of the rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, referring to the national standard GB / T31968 - 2015; and / or

[0025] The particle size of the zirconium boride fine powder is 20 - 30 μm; the zirconium boride fine powder is chemically pure; and / or,

[0026] The particle size of the zirconium phosphate fine powder is 15 - 20 μm; the zirconium phosphate fine powder is chemically pure.

[0027] A crucible for sintering a high - nickel NCM811 series ternary cathode material prepared by the above - mentioned preparation method.

[0028] The beneficial effects of the present invention are as follows:

[0029] (1) The process of the present invention is simple. It only needs to mix particles with fine powder materials and combine casting and vibration molding, without large - scale mechanical pressing equipment or special raw materials and treatment means, reducing the development cost of the crucible.

[0030] (2) The present invention selects fused zirconium spinel as the main raw material. By utilizing the solid solution of zirconium - containing components in the magnesium - aluminum spinel crystal, the chemical stability and erosion resistance of the spinel are further improved. Combining the introduction of rare - earth composite components, the wettability between the crucible and the high - nickel NCM811 series ternary cathode material is reduced. From the perspective of increasing the interfacial wetting angle, the service performance of the crucible is improved.

[0031] (3) During the erosion process of the fused zirconium spinel and the high - nickel component of the ternary cathode material, the present invention utilizes the in - situ formed solid solutions such as magnesium - aluminum - nickel composite spinel to form an effective boundary barrier layer, resisting the further diffusion of lithium - containing and high - nickel components, and avoiding the cracking and damage of the crucible.

[0032] (4) Through the optimization of raw material components, the present invention avoids introducing silicon - containing and free alumina components, reducing the content of acidic components in the crucible components, which is beneficial to improving the alkali - erosion resistance of the crucible.

[0033] (5) During the high - temperature sintering process of zirconium boride, the present invention forms a ceramic bond through oxidation, ensuring the medium - temperature (600 - 900 °C) strength of the crucible, avoiding the cracking and damage of the crucible in the medium - temperature section, and improving the yield of the crucible; at the same time, the medium environment provided by the ceramic phase containing boron components is beneficial to accelerating the diffusion of ZrO2 in the high - temperature section (> 900 °C), accelerating the high - temperature sintering process, reducing the sintering temperature of the crucible, and saving energy and protecting the environment.

[0034] (6) The present invention selects lime milk as the binder, which not only does not introduce other impurity components, but also increases the alkalinity of the sagger material system, facilitating resistance to the erosion of strongly alkaline components in the ternary cathode material. In addition, the active CaO microcrystals decomposed from lime milk at high temperatures can in-situ form calcium zirconate with the colloidal particles in the zirconia sol and the zirconium-containing components formed by the oxidation of zirconium boride. On the one hand, it improves the sintering performance of the sagger, promotes the sintering and densification of the matrix, and increases the strength of the sagger. On the other hand, by utilizing the non-wettability and low diffusion rate of calcium zirconate, it blocks the penetration of high-nickel components into the sagger. In addition, its excellent thermal shock resistance is used to improve the service life of the sagger.

[0035] (7) The raw material components of the present invention do not need to introduce other loss-on-ignition or volatile salt components (such as carbonates, nitrates, chlorides, fluorides and other salts). Except for the free water in the binder that escapes at low temperatures, it avoids the decomposition and escape of high-temperature salts leaving pore channels, further improving the density of the material, reducing the porosity of the sagger, and enhancing the erosion and penetration resistance of the sagger.

[0036] The sagger for sintering high-nickel NCM811 series ternary cathode materials prepared by the present invention, after testing:

[0037] (GB / T 2997-2015) Bulk density: 2.46 - 2.58 g / cm 3 ;

[0038] (GB / T 2997-2015) Apparent porosity: 16.6 - 18.5%;

[0039] (GB / T 2072-2008) Compressive strength: 42 - 54 MPa;

[0040] The residual flexural strength retention rate of the 1100 °C cyclic water-cooling 3 times thermal shock stability test (GB / T30873-2014) is 95 - 97%, and the strength change rate of the 1100 °C × 30 h alkali resistance test (GB / T14983-2008) is 2.8 - 3.5%. Description of the Drawings

[0041] Figure 1 It is the CaO-ZrO2 binary phase diagram.

[0042] Figure 2 It is the SEM image of the sagger for sintering high-nickel NCM811 series ternary cathode materials prepared in Example 1. Detailed Embodiments

[0043] The following are specific embodiments of the present invention in combination with the drawings, further describing the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0044] Example 1

[0045] A method for preparing a sagger for sintering a high-nickel NCM811 series ternary positive electrode material, the specific steps are as follows:

[0046] 1) adding the materials in a mass ratio of fused zirconium spinel particles: fused zirconium spinel fine powder: rare earth composite yttrium zirconium ceramic powder: zirconium boride fine powder to a high-speed mixer and mixing for 30 minutes to obtain a premix;

[0047] 2) adding 3 wt % of lime milk and 5 wt % of zirconium oxide sol to the premix in sequence, stirring for 20 to 25 minutes to obtain a mixture;

[0048] 3) adding the mixed material into a mold, pouring and vibrating the mold, curing at 25-30° C. for 4-6 hours, demolding, and obtaining a green body;

[0049] 4) After the green body is dried at 100-110° C. for 5-6 hours, it is sintered in a tunnel kiln at 1325° C. for 4 hours and cooled to room temperature to obtain a sagger for sintering high-nickel NCM811 series ternary positive electrode materials.

[0050] Lime milk is prepared from water and calcium hydroxide fine powder with a particle size of ≤20μm, wherein the mass ratio of water to calcium hydroxide fine powder is 3:1.

[0051] The solid content of the zirconium oxide sol is 30 wt %.

[0052] The particle size of the fused zircon spinel particles is 0.5-2.5 mm, wherein the mass ratio of [0.5-1.0 mm] particles, (1.0-1.5 mm] particles, and (1.5-2.5 mm] particles is 12:13:61; in the chemical composition of the fused zircon spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is 11:53:29; the sum of the contents of ZrO2, MgO, and Al2O3 is 99-99.9 wt%;

[0053] The particle size of the fused zirconium spinel fine powder is 40-45 μm; the mass ratio of ZrO2, MgO and Al2O3 is 14:52:27; the sum of the contents of ZrO2, MgO and Al2O3 is 99-99.9wt%.

[0054] The grade of rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, refer to the national standard GB / T31968-2015.

[0055] The particle size of the zirconium boride fine powder is 20-30 μm; the zirconium boride fine powder is chemically pure.

[0056] The particle size of the zirconium phosphate fine powder is 15-20 μm; the zirconium phosphate fine powder is chemically pure.

[0057] Figure 1 It is the phase diagram of the CaO-ZrO2 binary system.

[0058] Figure 2 It is the SEM image of the crucible for sintering the high-nickel NCM811 series ternary cathode material prepared in Example 1. It can be seen that the aggregate-matrix combination is tight, the granular materials are distributed inlaid in the matrix, there is no obvious vitreous phase, and at the same time, the high-content yttrium-zirconium components in the matrix fine powder are diffusely distributed and filled densely, which is beneficial to improving the erosion resistance and permeability of the crucible.

[0059] The crucible for sintering the high-nickel NCM811 series ternary cathode material prepared in this example was tested:

[0060] (GB / T 2997-2015) Bulk density: 2.52 g / cm 3 ;

[0061] (GB / T 2997-2015) Apparent porosity: 17.2%;

[0062] (GB / T 2072-2008) Compressive strength: 54 MPa;

[0063] The residual flexural strength retention rate of the thermal shock stability test (GB / T30873-2014) with cyclic water cooling 3 times at 1100 °C is 96%, and the strength change rate of the alkali resistance test (GB / T14983-2008) at 1100 °C × 30 h is 2.8%.

[0064] Example 2

[0065] A preparation method of a crucible for sintering a high-nickel NCM811 series ternary cathode material, the specific steps are as follows:

[0066] 1) Weigh the electrofused zircon spinel particles, electrofused zircon spinel fine powder, rare earth composite yttrium-zirconium ceramic powder, and zirconium boride fine powder according to the mass ratio of 100:57:6:4, add them to a high-speed mixer, and mix for 35 minutes to obtain a premix;

[0067] 2) Add lime milk accounting for 4 wt% of the premix and zirconia sol accounting for 6 wt% of the premix to the premix in sequence, and stir for 20 - 25 minutes to obtain a mixture;

[0068] 3) Add the mixture to a mold, pour and vibrate to form, cure at 25 - 30 °C for 4 - 6 hours, and demold to obtain a green body;

[0069] 4) After drying the green body at 100 - 110 °C for 5 - 6 hours, keep it warm at 1355 °C in a tunnel kiln for 5 hours, and cool it to room temperature to obtain the crucible for sintering the high-nickel NCM811 series ternary cathode material.

[0070] The lime milk is prepared from water and calcium hydroxide fine powder with a particle size of ≤20 μm, and the mass ratio of water to calcium hydroxide fine powder is 2:1.

[0071] The solid content of the zirconia sol is 30 wt%.

[0072] The particle size of the fused zirconia spinel particles is 0.5 - 2.5 mm, and the mass ratio of the [0.5 - 1.0 mm] particles, (1.0 - 1.5 mm] particles, and (1.5 - 2.5 mm] particles is 10:15:60; in the chemical composition of the fused zirconia spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is 15:55:20; the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%;

[0073] The particle size of the fused zirconia spinel fine powder is 40 - 45 μm; the mass ratio of ZrO2, MgO, and Al2O3 is 10:50:30; the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%.

[0074] The grade of the rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, see the national standard GB / T31968 - 2015.

[0075] The particle size of the zirconium boride fine powder is 20 - 30 μm; the zirconium boride fine powder is chemically pure.

[0076] The particle size of the zirconium phosphate fine powder is 15 - 20 μm; the zirconium phosphate fine powder is chemically pure.

[0077] The sagger for sintering the high - nickel NCM811 series ternary cathode material prepared in this example was tested:

[0078] (GB / T 2997 - 2015) Bulk density: 2.58 g / cm 3 ;

[0079] (GB / T 2997 - 2015) Apparent porosity: 16.6%;

[0080] (GB / T 2072 - 2008) Compressive strength: 53 MPa;

[0081] The residual flexural strength retention rate of the 1100°C cyclic water - cooling 3 - time thermal shock stability test (GB / T30873 - 2014) is 95%, and the strength change rate of the 1100°C × 30 h alkali - resistance test (GB / T14983 - 2008) is 2.9%.

[0082] Example 3

[0083] A preparation method of a sagger for sintering a high - nickel NCM811 series ternary cathode material, the specific steps are as follows:

[0084] 1) Weigh the electrofused zircon spinel particles, electrofused zircon spinel fine powder, rare earth composite yttrium zirconium ceramic powder, and zirconium boride fine powder according to the mass ratio of 100:42:14:6, add them to a high-speed mixer, and mix for 25 minutes to obtain a premix.

[0085] 2) Add lime milk accounting for 2 wt% of the premix and zirconia sol accounting for 4 wt% of the premix to the premix in sequence, and stir for 20 - 25 minutes to obtain a mixture.

[0086] 3) Add the mixture to a mold, pour and vibrate to form, cure at 25 - 30 °C for 4 - 6 hours, and demold to obtain a green body.

[0087] 4) After drying the green body at 100 - 110 °C for 5 - 6 hours, keep it at 1315 °C in a tunnel kiln for 6 hours for firing, and cool it to room temperature to obtain the sagger for sintering the high-nickel NCM811 series ternary cathode material.

[0088] The lime milk is prepared from water and calcium hydroxide fine powder with a particle size ≤ 20 μm, and the mass ratio of water to calcium hydroxide fine powder is 3:1.

[0089] The solid content of the zirconia sol is 25 wt%.

[0090] The particle size of the electrofused zircon spinel particles is 0.5 - 2.5 mm, and the mass ratio of the particles in the range of [0.5 - 1.0 mm], (1.0 - 1.5 mm], and (1.5 - 2.5 mm] is 15:10:65; in the chemical composition of the electrofused zircon spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is 10:50:30; the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%.

[0091] The particle size of the electrofused zircon spinel fine powder is 40 - 45 μm; the mass ratio of ZrO2, MgO, and Al2O3 is 15:55:20; the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%.

[0092] The grade of the rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, referring to the national standard GB / T31968 - 2015.

[0093] The particle size of the zirconium boride fine powder is 20 - 30 μm; the zirconium boride fine powder is of chemical purity.

[0094] The particle size of the zirconium phosphate fine powder is 15 - 20 μm; the zirconium phosphate fine powder is of chemical purity.

[0095] The sagger for sintering the high-nickel NCM811 series ternary cathode material prepared in this example, after testing:

[0096] (GB / T 2997-2015) Bulk density: 2.46g / cm 3 ;

[0097] (GB / T 2997-2015) Apparent porosity: 18.5%;

[0098] (GB / T 2072-2008) compressive strength: 42MPa;

[0099] The residual flexural strength retention rate of the thermal shock stability test (GB / T30873-2014) with 1100℃ circulating water cooling for 3 times is 97%, and the strength change rate of the 1100℃×30h alkali resistance test (GB / T14983-2008) is 3.5%.

[0100] Comparative Example 1

[0101] A method for preparing a sagger for sintering NCM-based ternary positive electrode materials, the specific steps are as follows:

[0102] 1) adding the materials in a mass ratio of fused zirconium spinel particles: fused zirconium spinel fine powder: rare earth composite yttrium zirconium ceramic powder: zirconium boride fine powder to a high-speed mixer and mixing for 35 minutes to obtain a premix;

[0103] 2) adding 4 wt % of lime milk and 6 wt % of zirconium oxide sol to the premix in sequence, stirring for 20 to 25 minutes to obtain a mixture;

[0104] 3) adding the mixed material into a mold, pouring and vibrating the mold, curing at 25-30° C. for 4-6 hours, demolding, and obtaining a green body;

[0105] 4) After the green body is dried at 100-110° C. for 5-6 hours, it is sintered in a tunnel kiln at 1420° C. for 5 hours, and cooled to room temperature to obtain a sagger for sintering high-nickel NCM811 series ternary positive electrode materials.

[0106] Lime milk is prepared from water and calcium hydroxide fine powder with a particle size of ≤20μm, wherein the mass ratio of water to calcium hydroxide fine powder is 2:1.

[0107] The solid content of the zirconium oxide sol is 30 wt %.

[0108] The particle size of the fused zircon spinel particles is 0.5-2.5 mm, wherein the mass ratio of [0.5-1.0 mm] particles, (1.0-1.5 mm] particles, and (1.5-2.5 mm] particles is 10:15:60; in the chemical composition of the fused zircon spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is 15:55:20; the sum of the contents of ZrO2, MgO, and Al2O3 is 99-99.9 wt%;

[0109] The particle size of the electrofused zirconium spinel fine powder is 40 - 45 μm; the mass ratio of ZrO2, MgO and Al2O3 is 10:50:30; the sum of the contents of ZrO2, MgO and Al2O3 is 99 - 99.9 wt%.

[0110] The grade of the rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, see the national standard GB / T31968 - 2015.

[0111] The particle size of the zirconium boride fine powder is 20 - 30 μm; the zirconium boride fine powder is chemically pure.

[0112] The particle size of the zirconium phosphate fine powder is 15 - 20 μm; the zirconium phosphate fine powder is chemically pure.

[0113] The sagger for sintering the high - nickel NCM811 series ternary cathode material prepared in this comparative example was tested:

[0114] (GB / T 2997 - 2015) Bulk density: 2.85 g / cm 3 ;

[0115] (GB / T 2997 - 2015) Apparent porosity: 15.1%;

[0116] (GB / T 2072 - 2008) Compressive strength: 66 MPa;

[0117] The residual flexural strength retention rate of the thermal shock stability test (GB / T30873 - 2014) with 3 cycles of water cooling at 1100 °C is 83%, and the strength change rate of the alkali resistance test (GB / T14983 - 2008) at 1100 °C × 30 h is 6.9%.

[0118] Compared with Example 2, it can be seen that increasing the addition amount of zirconium boride and raising the sintering temperature improve the sintering densification degree of the sagger by increasing the liquid phase amount. However, due to the reduction of pores, the thermal shock resistance of the sagger is significantly reduced; in addition, due to the increase of the boron - containing component, the sintering combination of ZrO2 - CaO during the sintering process of the sagger is inhibited, thereby damaging the erosion resistance of the sagger.

[0119] For those not covered above, the prior art shall apply.

[0120] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications, supplements, or use similar means of substitution to the described specific embodiments, but will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation method of a sagger for sintering a high-nickel NCM811 series ternary cathode material, characterized in that, The specific steps are as follows: S1. Mix fused zirconia spinel particles, fused zirconia spinel fine powder, rare earth composite yttrium zirconium ceramic powder, and zirconium boride fine powder to obtain a premix; S2. Sequentially add lime milk and zirconia sol to the premix to obtain a mixture; S3. Cast and vibrate the mixture to form, cure, and demold to obtain a green body; S4. Dry and heat-treat the green body and then cool it to room temperature to obtain a crucible for sintering high-nickel NCM811 series ternary cathode materials.

2. The preparation method of a sagger for sintering a high-nickel NCM811 series ternary cathode material as described in claim 1, characterized in that, The mass ratio of fused zirconia spinel particles : fused zirconia spinel fine powder : rare earth composite yttrium zirconium ceramic powder : zirconium boride fine powder is 100 : (42 - 57) : (6 - 14) : (4 - 8).

3. The preparation method of a sagger for sintering a high-nickel NCM811 series ternary cathode material as described in claim 1, characterized in that, The lime milk is prepared from water and calcium hydroxide fine powder with a particle size ≤ 20 μm, and the mass ratio of water to calcium hydroxide fine powder is (2 - 3) :

1.

4. The preparation method of a crucible for sintering a high-nickel NCM811 series ternary cathode material as described in claim 1, characterized in that, The lime milk accounts for 2 - 4 wt% of the premix.

5. The preparation method of a crucible for sintering a high-nickel NCM811 series ternary cathode material as described in claim 1, characterized in that, The solid content of the zirconia sol is 25 - 30 wt%; the zirconia sol accounts for 4 - 6 wt% of the premix.

6. The preparation method of a sagger for sintering a high-nickel NCM811 series ternary cathode material as described in claim 1, characterized in that, In step S4, the green body is dried at 100 - 110 °C for 5 - 6 hours.

7. The preparation method of a crucible for sintering a high-nickel NCM811 series ternary cathode material according to any one of claims 1-6, characterized in that, In step S4, the heat treatment is carried out at 1315 - 1355 °C for 4 - 6 hours.

8. The preparation method of a crucible for sintering a high-nickel NCM811 series ternary cathode material according to any one of claims 1-6, characterized in that, The particle size of the fused zirconia spinel particles is 0.5 - 2.5 mm, and the mass ratio of particles in the range of [0.5 - 1.0 mm], (1.0 - 1.5 mm], and (1.5 - 2.5 mm] is (10 - 15) : (10 - 15) : (60 - 65); in the chemical composition of the fused zirconia spinel particles, the mass ratio of ZrO2, MgO, and Al2O3 is (10 - 15) : (50 - 55) : (20 - 30); the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%; and / or, The particle size of the fused zirconia spinel fine powder is 40 - 45 μm; the mass ratio of ZrO2, MgO, and Al2O3 is (10 - 15) : (50 - 55) : (20 - 30); the sum of the contents of ZrO2, MgO, and Al2O3 is 99 - 99.9 wt%.

9. The preparation method of a sagger for sintering a high-nickel NCM811 series ternary cathode material according to any one of claims 1-6, characterized in that, The grade of the rare earth composite yttrium zirconium ceramic powder is YZ7.2QLC, referring to the national standard GB / T31968 - 2015; and / or, The particle size of the zirconium boride fine powder is 20 - 30 μm; the zirconium boride fine powder is chemically pure.

10. A crucible for sintering high-nickel NCM811 series ternary cathode materials prepared by the preparation method according to any one of claims 1 - 9.

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