A method for preparing a sagger for sintering positive electrode materials of sodium ion batteries

Abstract

The present invention discloses a preparation method of a crucible for sintering anode materials of sodium ion batteries, comprising the following steps: step 1) mixing refractory raw materials, water, and a binder to obtain a crucible raw material; the refractory raw material comprises the following components by mass fraction: 25-30% of a cordierite-mullite mixture with a particle size of 1-2 mm; 15-20% of a cordierite-mullite mixture with a particle size of 0.5-1 mm; 8-12% of a cordierite-mullite mixture with a particle size of 0.005-0.5 mm; and 40-50% of a powder matrix material with a particle size of less than 0.005 mm; step 2) shaping the crucible raw material and sintering it to obtain a crucible for sintering anode materials of sodium ion batteries, wherein the sintering temperature is 1300-1400° C. and the sintering time is 20-30 hours. The present invention increases the number of uses of the crucible by optimizing the formula and process, thereby effectively improving the service life of the crucible.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium batteries, and in particular relates to a method for preparing a sagger for sintering positive electrode materials of sodium ion batteries. Background Art

[0002] During the sintering process of sodium battery positive electrode materials, the use environment of the sodium ion crucible (crucible) is 900-1000 degrees, and the cycle time of one cycle is about 20 hours. During the sintering process of the sodium ion battery positive electrode material, the bottom material reacts with the crucible. Because Na is highly corrosive and the material is more likely to absorb water, the bottom material is more easily corroded, making the bottom more fragile. If the existing lithium battery positive electrode material crucible is used, the crucible will be subjected to great tensile and compressive stresses during the continuous heating and cooling process. If the stress is not released in time, the crucible will produce tiny cracks. As the cracks continue to expand, it will eventually stop being used due to cracking, and its service life will be significantly reduced. Therefore, the existing lithium battery positive electrode material crucible is not suitable for the sintering of sodium battery positive electrode materials.

[0003] In order to solve the problem that a sagger for sintering anode materials of sodium ion batteries is prone to cracking, the present invention proposes a new sagger for sintering anode materials of sodium ion batteries. Summary of the Invention

[0004] The purpose of the present invention is to provide a new sagger for sintering positive electrode materials for sodium ion batteries to solve the problem that saggers for sintering positive electrode materials for sodium ion batteries are prone to cracking. The present invention adopts the following technical solutions:

[0005] A method for preparing a sagger for sintering a positive electrode material for a sodium ion battery comprises the following steps:

[0006] Step 1) Mixing refractory raw materials, water, and a binder to obtain a box body raw material; the refractory raw materials contain the following components in mass fractions:

[0007] 25-30% of a cordierite-mullite mixture with a particle size of 1-2 mm;

[0008] 15-20% of a cordierite-mullite mixture with a particle size of 0.5-1 mm;

[0009] 8-12% of a cordierite-mullite mixture having a particle size of 0.005-0.5 mm;

[0010] 40-50% of the powder matrix material has a particle size of less than 0.005 mm;

[0011] Step 2) The sagger body raw material is formed and sintered to obtain a sagger for sintering the positive electrode material of the sodium ion battery, the sintering temperature is 1300-1400° C., and the sintering time is 20-30 hours.

[0012] Optionally, the amount of water used is 4.0-6.0% of the mass of the refractory raw material.

[0013] Optionally, the binder is calcium lignin sulfonate;

[0014] The amount of the binder used is 4-5% of the mass of the refractory raw material.

[0015] Optionally, the mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 1-2 mm is 1:0.6-1.5.

[0016] The mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 1-2 mm is 1:0.5-2;

[0017] The mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 0.005 to 0.5 mm is 1:0.5 to 2.

[0018] Optionally, the powder matrix material contains cordierite powder, mullite powder, clay and alumina.

[0019] Optionally, the powder matrix material with a particle size smaller than 0.005 mm has a particle size of 3 to 5 μm.

[0020] Optionally, the refractory raw material comprises the following components in mass fractions:

[0021] 30% cordierite-mullite mixture with a particle size of 1-2 mm;

[0022] 15% cordierite-mullite mixture with a particle size of 0.5-1 mm;

[0023] 10% of a cordierite-mullite mixture with a particle size of 0.005 to 0.5 mm;

[0024] 5-10% cordierite powder;

[0025] 2-5% mullite powder;

[0026] 15-20% clay;

[0027] 15-20% alumina.

[0028] Optionally, the method for molding the box body raw material is to use a hydraulic press to press the box body raw material into shape, and the pressing pressure is 20 to 25 MPa.

[0029] The present invention also provides a sagger prepared by the above preparation method for sintering positive electrode materials for sodium ion batteries.

[0030] Optionally, the box body is square, and the corners of the box body side walls are set to be rounded chamfers.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention adjusts the gradation of large and medium particles in the raw materials and reasonably proportions the low-expansion raw materials, thereby ensuring sufficient strength of the sagger while withstanding thermal stress. The optimization of the formula and process increases the number of uses of the sagger, thereby effectively improving the service life of the sagger by more than 50% as a whole, and solving the problem of easy cracking of the sagger of the sodium ion battery positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a schematic diagram of the box body. DETAILED DESCRIPTION

[0035] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0036] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0037] Example 1

[0038] Step 1) Mixing refractory raw materials, water, and a binder to obtain a box body raw material; the refractory raw materials contain the following components in mass fractions:

[0039] 30% cordierite-mullite mixture with a particle size of 1-2 mm, wherein the weight ratio of cordierite to mullite is 1:1;

[0040] 15% cordierite-mullite mixture with a particle size of 0.5-1 mm, wherein the weight ratio of cordierite to mullite is 1:1;

[0041] 10% of a cordierite-mullite mixture with a particle size of 0.005 to 0.5 mm, wherein the weight ratio of cordierite to mullite is 1:1;

[0042] 45% of the powder matrix material has a particle size of less than 0.005 mm; including:

[0043] 10% cordierite powder.

[0044] 5% mullite powder.

[0045] 15% clay.

[0046] 15% alumina.

[0047] By adjusting the particle size ratio of the refractory raw materials, the interior of the sagger can withstand the stress caused by the hot and cold changes, so the thermal shock is better.

[0048] The amount of water used is 4.5% of the mass of the refractory raw material. The binder is calcium lignin sulfonate, and the amount of the binder used is 4.5% of the mass of the refractory raw material. The addition of water and binder during the mixing process can improve the state of the material and achieve a more uniform effect.

[0049] Step 2) Add the raw material of the sagger into the mold and use a 1250T hydraulic press to press and form it at 22MPa, and then sinter it at 1300℃ for 24h to obtain a sagger for sintering the positive electrode material of sodium ion battery. Figure 1 shown.

[0050] Example 2

[0051] Step 1) Mixing refractory raw materials, water, and a binder to obtain a box body raw material; the refractory raw materials contain the following components in mass fractions:

[0052] 28% cordierite-mullite mixture with a particle size of 1-2 mm, wherein the weight ratio of cordierite to mullite is 1:2;

[0053] 20% cordierite-mullite mixture with a particle size of 0.5-1 mm, wherein the weight ratio of cordierite to mullite is 1:0.5;

[0054] 12% of a cordierite-mullite mixture having a particle size of 0.005 to 0.5 mm, wherein the weight ratio of cordierite to mullite is 1:1;

[0055] 40% of the powder matrix material has a particle size of less than 0.005 mm; including:

[0056] 5% cordierite powder.

[0057] 5% mullite powder.

[0058] 15% clay.

[0059] 15% alumina.

[0060] By adjusting the particle size ratio of the refractory raw materials, the interior of the sagger can withstand the stress caused by the hot and cold changes, so the thermal shock is better.

[0061] The amount of water used is 4.5% of the mass of the refractory raw material. The binder is calcium lignin sulfonate, and the amount of the binder used is 4.5% of the mass of the refractory raw material.

[0062] Step 2) The sagger body raw material is added to the mold and pressed using a 1250T hydraulic press at 22MPa, and then sintered at 1300°C for 24h to obtain a sagger for sintering the positive electrode material of the sodium ion battery.

[0063] Example 3

[0064] Step 1) Mixing refractory raw materials, water, and a binder to obtain a box body raw material; the refractory raw materials contain the following components in mass fractions:

[0065] 25% cordierite-mullite mixture with a particle size of 1-2 mm, wherein the weight ratio of cordierite to mullite is 1:0.5;

[0066] 15% cordierite-mullite mixture with a particle size of 0.5-1 mm, wherein the weight ratio of cordierite to mullite is 1:2;

[0067] 10% of a cordierite-mullite mixture with a particle size of 0.005 to 0.5 mm, wherein the weight ratio of cordierite to mullite is 1:1;

[0068] 50% of the powder matrix material has a particle size of less than 0.005 mm; including:

[0069] 10% cordierite powder.

[0070] 4% mullite powder.

[0071] 16% clay.

[0072] 20% alumina.

[0073] By adjusting the particle size ratio of the refractory raw materials, the interior of the sagger can withstand the stress caused by the hot and cold changes, so the thermal shock is better.

[0074] The amount of water used is 4.5% of the mass of the refractory raw material. The binder is calcium lignin sulfonate, and the amount of the binder used is 4-5% of the mass of the refractory raw material.

[0075] Step 2) The sagger body raw material is added to the mold and pressed using a 1250T hydraulic press at 22MPa, and then sintered at 1300°C for 24h to obtain a sagger for sintering the positive electrode material of the sodium ion battery.

[0076] Comparative Example 1

[0077] In this comparative example, a conventional lithium battery positive electrode material box body is prepared by uniformly mixing a refractory raw material, water, and a binder to obtain a box body raw material, wherein the refractory raw material is as follows:

[0078] 20% 1-2mm cordierite-mullite mixture;

[0079] 40% 0.5-1mm cordierite-mullite mixture;

[0080] 40% cordierite-mullite mixture below 0.5mm.

[0081] The amount of water used is 4.5% of the mass of the refractory raw material. The binder is calcium lignin sulfonate, and the amount of the binder used is 4% of the mass of the refractory raw material.

[0082] Step 2) The sagger body raw material is added into a mold and pressed at 24 MPa using a 1250T hydraulic press, and then sintered at 1400°C for 24 hours to obtain a sagger.

[0083] Performance test

[0084] The casings of Example 1 and Comparative Example 1 were heated to 30°C and then water-cooled. After five cycles, multiple cracks appeared in the comparative example, while no cracks appeared in the casing of Example 1. The casings of Examples 2 and 3 were tested using the above method, and no cracks appeared on the casings.

[0085] The thermal expansion coefficient of Example 1 and Comparative Example 1 was measured using a thermal expansion coefficient meter. The thermal expansion coefficient of Example 1 was 2.75×10 -6 m / ℃, and that of comparative example 1 is 3.2×10 -6 m / ℃.

[0086] It can be seen that the sodium battery box body in Example 1 can withstand and absorb the stress caused by continuous changes in temperature, thereby ensuring a good thermal shock effect.

[0087] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a sagger for sintering a positive electrode material for a sodium ion battery, characterized in that: The method comprises the following steps: Step 1) uniformly mixing refractory raw materials, water and a binder to obtain a box body raw material; the refractory raw materials contain the following components in mass fractions: 25-30% of a cordierite-mullite mixture with a particle size of 1-2 mm; 15-20% of a cordierite-mullite mixture with a particle size of 0.5-1 mm; 8-12% of a cordierite-mullite mixture having a particle size of 0.005-0.5 mm; 40-50% of the powder matrix material has a particle size of less than 0.005 mm; Step 2) forming the sagger raw material and sintering it to obtain a sagger for sintering the positive electrode material of the sodium ion battery, the sintering temperature is 1300-1400° C., and the sintering time is 20-30 hours; The mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 1-2 mm is 1:0.6-1.5; the mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 0.5-1 mm is 1:0.5-2; The mass ratio of cordierite to mullite in the cordierite-mullite mixture with a particle size of 0.005-0.5 mm is 1:0.5-2; the powder matrix material contains cordierite powder, mullite powder, clay and alumina.

2. The method for preparing a sagger for sintering a positive electrode material for a sodium ion battery according to claim 1, wherein: The amount of water used is 4.0-6.0% of the mass of the refractory raw material.

3. The method for preparing a sagger for sintering a positive electrode material for a sodium ion battery according to claim 1, wherein: The binder is calcium lignin sulfonate; The amount of the binder used is 4-5% of the mass of the refractory raw material.

4. The method for preparing a sagger for sintering a positive electrode material for a sodium ion battery according to claim 1, wherein: The particle size of the powder matrix material with a particle size smaller than 0.005 mm is 3 to 5 μm.

5. The method for preparing a sagger for sintering a positive electrode material for a sodium ion battery according to claim 1, wherein: The refractory raw material comprises the following components by mass fraction: 30% cordierite-mullite mixture with a particle size of 1-2 mm; 15% of a cordierite-mullite mixture with a particle size of 0.5-1 mm; 10% of a cordierite-mullite mixture with a particle size of 0.005 to 0.5 mm; 5-10% cordierite powder; 2-5% mullite powder; 15-20% clay; 15-20% alumina.

6. The method for preparing a sagger for sintering a positive electrode material for a sodium ion battery according to claim 1, wherein: The method for molding the box body raw material is to use a hydraulic press to press the box body raw material into shape, and the pressing pressure is 20-25 MPa.

7. A sagger for sintering positive electrode materials for sodium ion batteries, prepared according to any one of claims 1 to 6.

8. The sagger for sintering anode materials for sodium ion batteries according to claim 7, characterized in that: The box body is square, and the corners of the box body side walls are set as round chamfers.

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