A high-nickel nca ternary lithium battery positive electrode solid-phase sintering saggar and a preparation method thereof

Abstract

The present application relates to the technical field of sagger, and particularly relates to a sagger for high-nickel NCA ternary lithium battery positive electrode solid-phase sintering and a preparation method thereof. The preparation method comprises the following steps: S1, mixing and grinding bauxite fine powder, active Al2O3 micro powder, talc fine powder, Si powder and boric acid to obtain a mixed powder; S2, adding silica sol and stirring to obtain a slurry; S3, spray granulating the slurry to obtain microspheric material; S4, placing the microspheric material in a nitrogen atmosphere, high-temperature heat preservation, cooling and sieving to obtain sintered microspheric material; S5, mixing and ball-milling magnesia-alumina spinel particles, mullite fine powder, sintered microspheric material, talc fine powder and cerium oxide fine powder to obtain a mixed material; S6, adding paper pulp waste liquid, mixing and sealing to obtain aging material; S7, pressing, drying, high-temperature heat preservation, cooling and sieving to obtain the sagger. The prepared sagger has good integrity, high yield, excellent sintering performance, high thermal shock stability, strong resistance to corrosion and strong permeability of high-nickel NCA ternary lithium battery positive electrode material.

Description

Technical Field

[0001] This invention relates to the field of sagger technology, and in particular to a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode and its preparation method. Background Technology

[0002] Ternary lithium batteries have achieved widespread application in the field of power batteries due to their high energy density, good cycle performance, and large capacity. Li Qin, Liang Wenying. Research progress on composite modification of ternary cathode materials [J]. Chemical New Materials Materials, 2024, 52(z1):1-4 Ternary lithium batteries mainly include lithium nickel cobalt aluminum oxide (NCA) and lithium nickel cobalt manganese oxide (NCM), which are a type of lithium-ion battery with nickel and cobalt as the main elements and manganese or aluminum salts to stabilize the chemical structure. Qin Cunpeng, Liu Jia Yi, Tan Xiaohua, et al. Li Ni 0.8 Co 0.15 Al 0.05 Research progress on oxide coating modification of O2(NCA) ternary cathode materials [J]. Electricity Chi Industry, 2019, 23(6):327-334 However, there are significant differences between the two:

[0003] (1) NCA has a higher energy density than NCM. This is because aluminum doping in the ternary system can improve the battery's cycle chemical stability. Zhang Busheng, Wu Yongqian, Zhang Ke, et al. Research progress on nickel-cobalt-aluminum ternary cathode materials [J]. Guangzhou Chemical Industry, 2017, 45(11):3-5 Therefore, NCA has good cyclic charge and discharge performance.

[0004] (2) In the NCA ternary system, aluminum is more likely to stabilize the high-nickel system, forming an aluminum-nickel spinel solid solution. Therefore, the NCA ternary system has a higher energy density. Yan Xiaocen, Du Chengtin, Ding Jiaqi, et al. Ternary cathode materials LiNi 0.8 Co 0.15 Al 0.05 Research progress on O2 preparation methods [J]. New Chemical Materials, 2024, 52(6):44-49 ).

[0005] (3) The preparation process of NCA ternary cathode material has higher requirements. Although aluminum is abundant and alumina is relatively inexpensive, the preparation process of NCA is more complex due to the fact that Al2O3 (including Al(OH)3) is easy to react with both acids and bases. In addition, unlike the air atmosphere used for solid-state sintering of NCM ternary cathode, NCA ternary cathode solid-state sintering adopts oxygen-rich or all-oxygen sintering. This is to promote the full oxidation of nickel and other elements in the raw material components. The sintering temperature control of NCA ternary cathode is more stringent. If the sintering temperature is too low, nickel is difficult to convert into a high valence state (+3 valence) and stabilize. If the temperature is too high, it will decompose back into a low valence state (+2 valence).

[0006] In general, the altered aluminum doping characteristics of the NCA ternary system lead to significant changes in many process factors, including sintering heat treatment temperature, grain growth and development, and surface coating. This results in a distinct difference between the saggers used for NCA solid-state sintering and those specifically designed for NCM heat treatment. In particular, the prevalence of NCM in domestic ternary cathode materials has, to some extent, hindered the research and development of saggers for NCA solid-state sintering, resulting in the near-complete application of dedicated saggers for high-nickel NCA ternary cathode solid-state sintering.

[0007] Currently, the development and industrial application of saggers for solid-state sintering of high-nickel NCA ternary lithium-ion battery cathodes in China mainly follow the approach of high-nickel NCM ternary lithium-ion battery cathodes, or draw on the solutions for sintering saggers specifically for cathode materials such as lithium cobalt oxide, lithium iron phosphate, and lithium manganese oxide. Most saggers use cordierite, mullite, corundum, or spinel as the main raw materials, and incorporate zirconium-containing components and non-oxide components. A long-life ternary cathode material sintering crucible and preparation process, CN202311744260.5 The finished sagger is produced by optimizing the proportions, mixing, trapping, molding, and then drying and firing. On the one hand, as mentioned above, the different incorporation characteristics of manganese / aluminum elements lead to significant differences in the corrosion and damage of the saggers. Saggers used for NCM heat treatment have a service life of over 40 cycles, while saggers used for NCA solid-state sintering only have a lifespan of 4-8 cycles. On the other hand, the manufacturing processes and raw materials for NCA and NCM or other cathode materials are not entirely the same, thus the impact of the sagger on the quality of high-nickel ternary cathode materials varies significantly. Furthermore, most NCM high-nickel ternary cathode heat treatment saggers employ composite layer technology—a coating material with good corrosion resistance is laminated onto the inner wall (bottom and side walls) of the sagger. However, during cyclic service, the composite layer is prone to detachment and seep into the lithium-ion battery cathode material, which will also seriously affect the quality and performance of the cathode material. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of the prior art by proposing a crucible for solid-state sintering of high-nickel NCA ternary lithium-ion battery cathodes and its preparation method. This method is simple, requires no composite layer or other coating, and the prepared crucible has good integrity, high yield, excellent sintering performance, high thermal shock stability, and strong resistance to erosion and penetration of high-nickel NCA ternary lithium-ion battery cathode materials.

[0009] The present invention discloses a method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, comprising the following steps:

[0010] S1. Mix and grind bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid in a mass ratio of 100:(20~30):(40~60):(5~8):(3~6) until the particle size is ≤100μm to obtain mixed powder.

[0011] S2. Add 12-15% of silica sol (by mass of the mixed powder) to the mixed powder and stir to obtain a slurry;

[0012] S3. Spray granulation of the slurry to obtain microspheres;

[0013] S4. The microspheres are kept at 1180-1220°C for 6-8 hours under a nitrogen atmosphere, cooled to room temperature in the furnace, and then passed through a 250-mesh sieve. The material passing through the sieve is taken to obtain the calcined microspheres.

[0014] S5. The magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder are mixed in a mass ratio of 100:(10~12):(55~60):(5~8):(2~4) to obtain a mixture.

[0015] S6. Add 3.5-4.5% by weight of pulp waste liquor to the mixture, mix, and then seal the mixture to obtain aged material;

[0016] S7. Press the aged material into shape, dry it, and then keep it at 1360-1420℃ for 3-4 hours. Cool it to room temperature in the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

[0017] Furthermore, the silica sol has a pH value of 9-10; a solid content of 30-35%; and a particle size of 25-70 nm.

[0018] Furthermore, the magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is (20–30):(25–30):(25–35); and the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

[0019] Furthermore, the mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, [50 μm–80 μm] fine powder, and [80 μm–100 μm] fine powder is (10–15):(30–35):(45–55); the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

[0020] Furthermore, the particle size of the talc powder is ≤80μm; the particle size of the cerium oxide powder is ≤40μm.

[0021] Furthermore, in step S3, the slurry is dried in a spray granulator at 180–220°C for 30–40 seconds to obtain microspheres.

[0022] Furthermore, the pH value of the pulp waste liquid is 6.5 to 7.0.

[0023] Furthermore, in step S6, the mixture is stirred for 5-8 minutes and then sealed and foraged for 4-5 hours.

[0024] Furthermore, in step S7, the aged material is pressed into shape at 60-80 MPa and dried at 25-35°C for 10-12 hours.

[0025] A crucible for solid-state sintering of high-nickel NCA ternary lithium battery cathode prepared by the above-described preparation method.

[0026] The beneficial effects of this invention are:

[0027] (1) This invention starts with the matrix part of the sagger and uses the liquid medium environment created by boric acid at high temperature through in-situ silicothermic reaction, combined with the decomposition and nitridation of bauxite and pyrophyllite, to form plate-like SiAlON and layered BN, which are high-temperature and high-thermal-conductivity phases that are resistant to oxidation and corrosion, thereby improving the sagger's resistance to lithium nickel components and its thermal shock stability.

[0028] (2) The present invention uses spray-granulation-drying integrated technology to shape the matrix material. After high-temperature sintering, it is sieved, which improves the sphericity and regularity of the matrix material. This is beneficial to improving the dispersibility of the synthetic matrix material and maintaining the integrity of the synthetic matrix material, and significantly improving the service performance of the crucible components under high-temperature oxygen-rich or pure oxygen conditions.

[0029] (3) The present invention forms a skeleton by discrete distribution of magnesium aluminum spinel particles and constructs a dense network stack of the sagger by continuous filling of synthetic matrix material and mullite fine powder. The erosion reaction between mullite and high nickel NCA ternary lithium battery cathode material (during service) forms spodumene / spodumene, which reduces the thermal expansion of the sagger matrix and further improves the erosion resistance and service life of the sagger.

[0030] (4) This invention utilizes the high-temperature solid solution of cerium oxide and magnesium aluminum spinel to increase the melting point of the grain boundary phase of spinel-mullite. The non-wetting properties of cerium oxide fine powder form grain boundary pinning, which hinders the wetting and penetration of the high-nickel NCA ternary lithium battery positive electrode into the crucible, thus avoiding the adhesion and penetration of the positive electrode material into the crucible.

[0031] (5) This invention does not require the use of composite layers or composite coatings. It uses the overall mixing and dispersion and one-step pressing molding technology to prepare a homogeneous crucible, avoiding the peeling of composite layers or coatings, further ensuring the quality of high-nickel NCA ternary lithium battery cathode materials, and also improving the yield of crucibles.

[0032] The crucible used for solid-state sintering of the high-nickel NCA ternary lithium battery cathode prepared in this invention was tested and found to be:

[0033] Yield: 99.3%–99.7%; Apparent porosity: 12%–15% (GB / T2997-2015);

[0034] Flexural strength 18–24 MPa (GB / T3001-2017); residual flexural strength retention rate of 97–98% in 5 cycles of cyclic water cooling at 1100℃ (GB / T30873-2014); strength change rate of 1.8–2.2% in alkali resistance test at 1100℃ for 30 hours (GB / T14983-2008).

[0035] Therefore, the process of this invention is simple, and the prepared sagger has good integrity, high yield, excellent sintering performance, high thermal shock stability, and strong resistance to erosion and penetration of high-nickel NCA ternary lithium battery cathode materials. Attached Figure Description

[0036] Figure 1 SEM image of the high-nickel NCA ternary lithium battery cathode solid-state sintering crucible sample prepared in Example 1.

[0037] Figure 2 SEM image of the high-nickel NCA ternary lithium battery cathode solid-state sintering crucible sample prepared in Example 1 after etching. Detailed Implementation

[0038] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0039] Example 1

[0040] A method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, the specific steps of which are as follows:

[0041] S1. Add bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid to a high-energy ball mill and grind them until the particle size is ≤100μm to obtain a mixed powder.

[0042] S2. Add silica sol accounting for 14% of the mass of the mixed powder to the mixed powder, stir for 5-6 minutes to obtain a slurry;

[0043] S3. The slurry is fed into a spray granulator and dried at 210°C for 40 seconds to obtain microspheres;

[0044] S4. Place the microsphere material in a resistance furnace and keep it at 1210°C for 8 hours under a nitrogen atmosphere. After cooling to room temperature with the furnace, pass it through a 250-mesh round hole sieve and take the sieve-passed material to obtain the calcined microsphere material.

[0045] S5. Add magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder to a planetary ball mill at a mass ratio of 100:10:55:5:4 and mix for 15-20 minutes to obtain a mixture.

[0046] S6. Add 4.2% by mass of pulp waste liquor to the mixture, mix for 5-8 minutes, seal and allow to stand for 4-5 hours to obtain aged material;

[0047] S7. Press the aged material into shape at 60-80 MPa, dry it at 25-35℃ for 10-12 hours, place it in a high-temperature furnace, keep it at 1380℃ for 3 hours, and cool it to room temperature with the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

[0048] The silica sol has a pH of 9, a solid content of 33%, and a particle size of 25–70 nm.

[0049] The magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is 28:25:32; the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

[0050] The mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, (50 μm–80 μm] fine powder, and (80 μm–100 μm] fine powder is 10:34:55; the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

[0051] The particle size of fine talc powder is ≤80μm.

[0052] The particle size of cerium oxide fine powder is ≤40μm.

[0053] The pH value of pulp waste liquor is 6.5 to 7.0.

[0054] Figure 1 SEM images of crucible samples used for solid-state sintering of high-nickel NCA ternary lithium-ion battery cathodes. Figure 1 As can be seen, the particles are tightly bonded to the matrix material with no obvious boundary. The white bright spots of cerium oxide are solid-solid embedded between the spinel particles and the matrix. The sample has excellent overall bonding and high density.

[0055] Figure 2 SEM images of etched crucible samples used for solid-state sintering of high-nickel NCA ternary lithium-ion battery cathodes. Figure 2As can be seen, after the erosion reaction, the cerium oxide that was originally dissolved and embedded between the particles and the matrix is ​​in a "leached state" and is continuously distributed between the matrix. The sample is more tightly connected. This is mainly because the high-nickel NCA ternary cathode material reacts with the crucible body to form a low-expansion phase that fills the gaps between the particles. The sample maintains strong integrity. Although a small number of erosion cracks can be found, the sample does not crack, fall off or delaminate, indicating that the crucible sample has good erosion and penetration resistance.

[0056] The crucible used for solid-state sintering of the high-nickel NCA ternary lithium-ion battery cathode prepared in this embodiment was tested.

[0057] Yield rate 99.5%; apparent porosity 12% (GB / T2997-2015);

[0058] Flexural strength 20MPa (GB / T3001-2017); thermal shock stability test after 5 cycles of cyclic water cooling at 1100℃ (GB / T30873-2014) with a residual flexural strength retention rate of 98%; alkali resistance test at 1100℃ for 30h (GB / T14983-2008) with a strength change rate of 2.0%.

[0059] Example 2

[0060] A method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, the specific steps of which are as follows:

[0061] S1. Add bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid to a high-energy ball mill and grind them until the particle size is ≤100μm to obtain a mixed powder.

[0062] S2. Add silica sol accounting for 15% of the mass of the mixed powder to the mixed powder, stir for 5-6 minutes to obtain a slurry;

[0063] S3. The slurry is fed into a spray granulator and dried at 200°C for 35 seconds to obtain microspheres.

[0064] S4. Place the microsphere material in a resistance furnace and keep it at 1220°C for 7 hours under a nitrogen atmosphere. After cooling to room temperature with the furnace, pass it through a 250-mesh round hole sieve and take the sieve-passed material to obtain the calcined microsphere material.

[0065] S5. Add magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder to a planetary ball mill at a mass ratio of 100:12:60:6:4 and mix for 15-20 minutes to obtain a mixture.

[0066] S6. Add 4.0% by mass of pulp waste liquor to the mixture, mix for 5-8 minutes, seal and allow to stand for 4-5 hours to obtain aged material;

[0067] S7. Press the aged material into shape at 60-80 MPa, dry it at 25-35℃ for 10-12 hours, place it in a high-temperature furnace, keep it at 1420℃ for 3 hours, and cool it to room temperature with the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

[0068] The silica sol has a pH of 10, a solid content of 35%, and a particle size of 25–70 nm.

[0069] The magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is 25:30:26; the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

[0070] The mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, (50 μm–80 μm] fine powder, and (80 μm–100 μm] fine powder is 12:30:45; the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

[0071] The particle size of fine talc powder is ≤80μm.

[0072] The particle size of cerium oxide fine powder is ≤40μm.

[0073] The pH value of pulp waste liquor is 6.5 to 7.0.

[0074] The crucible used for solid-state sintering of the high-nickel NCA ternary lithium-ion battery cathode prepared in this embodiment was tested.

[0075] Yield rate 99.3%; apparent porosity 13% (GB / T2997-2015);

[0076] Flexural strength 22MPa (GB / T3001-2017); thermal shock stability test after 5 cycles of cyclic water cooling at 1100℃ (GB / T30873-2014) with a residual flexural strength retention rate of 97%; alkali resistance test at 1100℃ for 30h (GB / T14983-2008) with a strength change rate of 2.2%.

[0077] Example 3

[0078] A method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, the specific steps of which are as follows:

[0079] S1. Add bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid to a high-energy ball mill and grind them until the particle size is ≤100μm to obtain a mixed powder.

[0080] S2. Add silica sol accounting for 12% of the mass of the mixed powder to the mixed powder, stir for 5-6 minutes to obtain a slurry;

[0081] S3. The slurry is fed into a spray granulator and dried at 180°C for 30 seconds to obtain microspheres.

[0082] S4. Place the microsphere material in a resistance furnace and keep it at 1180°C for 6 hours under a nitrogen atmosphere. After cooling to room temperature with the furnace, pass it through a 250-mesh round hole sieve and take the sieve-passed material to obtain the calcined microsphere material.

[0083] S5. Add magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder to a planetary ball mill at a mass ratio of 100:10:56:7:3 and mix for 15-20 minutes to obtain a mixture.

[0084] S6. Add 4.5% by mass of pulp waste liquor to the mixture, mix for 5-8 minutes, seal and allow to stand for 4-5 hours to obtain aged material;

[0085] S7. Press the aged material into shape at 60-80 MPa, dry it at 25-35℃ for 10-12 hours, place it in a high-temperature furnace, keep it at 1360℃ for 4 hours, and cool it to room temperature with the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

[0086] The silica sol has a pH of 9, a solid content of 30%, and a particle size of 25–70 nm.

[0087] The magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is 30:26:35; the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

[0088] The mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, (50 μm–80 μm] fine powder, and (80 μm–100 μm] fine powder is 15:35:50; the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

[0089] The particle size of fine talc powder is ≤80μm.

[0090] The particle size of cerium oxide fine powder is ≤40μm.

[0091] The pH value of pulp waste liquor is 6.5 to 7.0.

[0092] The crucible used for solid-state sintering of the high-nickel NCA ternary lithium-ion battery cathode prepared in this embodiment was tested.

[0093] Yield rate 99.7%; apparent porosity 15% (GB / T2997-2015);

[0094] Flexural strength 24MPa (GB / T3001-2017); thermal shock stability test after 5 cycles of cyclic water cooling at 1100℃ (GB / T30873-2014) with a residual flexural strength retention rate of 97.2%; alkali resistance test at 1100℃ for 30h (GB / T14983-2008) with a strength change rate of 2.1%.

[0095] Example 4

[0096] A method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, the specific steps of which are as follows:

[0097] S1. Add bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid to a high-energy ball mill and grind them until the particle size is ≤100μm to obtain a mixed powder.

[0098] S2. Add silica sol accounting for 13% of the mass of the mixed powder to the mixed powder, stir for 5-6 minutes to obtain a slurry;

[0099] S3. The slurry is fed into a spray granulator and dried at 220°C for 30 seconds to obtain microspheres.

[0100] S4. Place the microsphere material in a resistance furnace and keep it at 1200℃ for 6 hours under a nitrogen atmosphere. After cooling to room temperature with the furnace, pass it through a 250-mesh round hole sieve and take the material passing through the sieve to obtain the calcined microsphere material.

[0101] S5. Add magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder to a planetary ball mill at a mass ratio of 100:11:58:8:2 and mix for 15-20 minutes to obtain a mixture.

[0102] S6. Add 3.5% by mass of pulp waste liquor to the mixture, mix for 5-8 minutes, seal and allow to stand for 4-5 hours to obtain aged material;

[0103] S7. Press the aged material into shape at 60-80 MPa, dry it at 25-35℃ for 10-12 hours, place it in a high-temperature furnace, keep it at 1400℃ for 4 hours, and cool it to room temperature with the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

[0104] The silica sol has a pH of 10, a solid content of 32%, and a particle size of 25–70 nm.

[0105] The magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is 20:28:25; the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

[0106] The mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, (50 μm–80 μm] fine powder, and (80 μm–100 μm] fine powder is 13:32:52; the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

[0107] The particle size of fine talc powder is ≤80μm.

[0108] The particle size of cerium oxide fine powder is ≤40μm.

[0109] The pH value of pulp waste liquor is 6.5 to 7.0.

[0110] The crucible used for solid-state sintering of the high-nickel NCA ternary lithium-ion battery cathode prepared in this embodiment was tested.

[0111] Yield rate 99.6%; apparent porosity 15% (GB / T2997-2015);

[0112] Flexural strength 18MPa (GB / T3001-2017); thermal shock stability test after 5 cycles of cyclic water cooling at 1100℃ (GB / T30873-2014) with a residual flexural strength retention rate of 97.6%; alkali resistance test at 1100℃ for 30h (GB / T14983-2008) with a strength change rate of 1.8%.

[0113] For any points not covered above, existing technologies shall apply.

[0114] Although 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 are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding 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 method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode, characterized in that, Includes the following steps: S1. Mix and grind bauxite fine powder, activated Al2O3 micro powder, pyrophyllite fine powder, Si powder and boric acid in a mass ratio of 100:(20~30):(40~60):(5~8):(3~6) until the particle size is ≤100μm to obtain mixed powder. S2. Add 12-15% of silica sol (by mass of the mixed powder) to the mixed powder and stir to obtain a slurry; S3. Spray granulation of the slurry to obtain microspheres; S4. The microspheres are kept at 1180-1220°C for 6-8 hours under a nitrogen atmosphere, cooled to room temperature in the furnace, and then passed through a 250-mesh sieve. The material passing through the sieve is taken to obtain the calcined microspheres. S5. The magnesium aluminum spinel particles, mullite fine powder, calcined microspheres, talc fine powder and cerium oxide fine powder are mixed in a mass ratio of 100:(10~12):(55~60):(5~8):(2~4) to obtain a mixture. S6. Add 3.5-4.5% by weight of pulp waste liquor to the mixture, mix, and then seal the mixture to obtain aged material; S7. Press the aged material into shape, dry it, and then keep it at 1360-1420℃ for 3-4 hours. Cool it to room temperature in the furnace to obtain a sagger for solid-state sintering of high-nickel NCA ternary lithium battery cathode.

2. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, The silica sol has a pH of 9-10; a solid content of 30-35%; and a particle size of 25-70 nm.

3. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, The magnesium aluminum spinel particles have a particle size of 0.1–2.5 mm, wherein the mass ratio of [0.1 mm–0.5 mm] particles, [1.0 mm–1.5 mm] particles, and [2.0 mm–2.5 mm] particles is (20–30):(25–30):(25–35); the SiO2 content of the magnesium aluminum spinel particles is ≤0.1 wt%.

4. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, The mullite fine powder has a particle size of 40–100 μm, wherein the mass ratio of [40 μm–50 μm] fine powder, [50 μm–80 μm] fine powder, and [80 μm–100 μm] fine powder is (10–15):(30–35):(45–55); the Fe2O3 content of the mullite fine powder is ≤0.1 wt%, and the TiO2 content is ≤0.2 wt%.

5. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, The particle size of the talc fine powder is ≤80μm; the particle size of the cerium oxide fine powder is ≤40μm.

6. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, In step S3, the slurry is fed into a spray granulator and dried at 180-220°C for 30-40 seconds to obtain microspheres.

7. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, The pH value of the pulp waste liquid is 6.5 to 7.

0.

8. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, In step S6, mix for 5-8 minutes and seal the mixture for 4-5 hours.

9. The method for preparing a crucible for solid-state sintering of a high-nickel NCA ternary lithium battery cathode as described in claim 1, characterized in that, In step S7, the aged material is pressed into shape at 60-80 MPa and dried at 25-35°C for 10-12 hours.

10. A crucible for solid-state sintering of a high-nickel NCA ternary cathode prepared by any one of claims 1-9.

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