Push plate for sintering hard carbon negative electrode and preparation method of push plate

Abstract

The invention provides a push plate for sintering a hard carbon negative electrode and a preparation method of the push plate, and belongs to the technical field of push plates. The refractory material is prepared from the following raw materials in parts by weight: 30-45 parts of modified alumina-based mullite, 10-20 parts of modified andalusite, 10-20 parts of SiC powder, 10-20 parts of alumina micro powder, 3-10 parts of kaolin and 5-10 parts of a binder. The high-temperature push plate prepared by the invention has excellent wear resistance, creep resistance and thermal shock resistance, good thermal conductivity, good mechanical property and good oxidative damage resistance, can be well matched with sintering of a hard carbon negative electrode material, and has a relatively good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of push plates, and in particular to a push plate for sintering a hard carbon negative electrode and a preparation method thereof. Background Art

[0002] Sodium-ion batteries (SIBs) primarily consist of a positive electrode, a negative electrode, an electrolyte, and a separator, and operate on a similar principle to lithium-ion batteries. The negative electrode material in SIBs acts as the primary sodium storage material, allowing sodium ions to be inserted or removed during charge and discharge. Therefore, the battery's capacity is positively correlated with the SIB's ability to store sodium ions. The choice of negative electrode material plays a crucial role in the development of SIBs. Hard carbon, due to its high stability, wide range of applications, low cost, and high reversible capacity, has become one of the preferred materials for SIB negative electrodes.

[0003] High-temperature pusher kilns are mainstream equipment used for processes such as sintering, carbonization, and pre-carbonization of hard carbon materials. They typically consist of a furnace body, heating system, and control system. The pusher plate is crucial for proper kiln operation and requires excellent wear resistance, creep resistance, and thermal shock resistance. Currently, the pusher plates used in high-temperature furnaces are primarily made of corundum-mullite, which has a high coefficient of thermal expansion, poor thermal shock resistance, and is prone to cracking during use. Summary of the Invention

[0004] The purpose of the present invention is to propose a push plate for sintering hard carbon negative electrodes and a preparation method thereof, which has excellent wear resistance, creep resistance and thermal shock resistance, good thermal conductivity, good mechanical properties, and good resistance to oxidation damage. It can well match the sintering of hard carbon negative electrode materials and has good application prospects.

[0005] The technical solution of the present invention is achieved as follows: The invention provides a push plate for sintering a hard carbon negative electrode, which is prepared from the following raw materials in parts by weight: 30-45 parts of modified alumina-based mullite, 10-20 parts of modified andalusite, 10-20 parts of SiC powder, 10-20 parts of alumina fine powder, 3-10 parts of kaolin, and 5-10 parts of a binder.

[0006] As a further improvement of the present invention, the preparation method of the modified alumina-based mullite is as follows: S1 mixed powder: The particle size ≦3mm alumina-based mullite powder and mesh size 300-400 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, ultrasonically shaken in a diamond suspension, then ultrasonically cleaned in alcohol, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. The surface-deposited powder was added to a Tris-HCl solution, dopamine hydrochloride was added, the mixture was heated with stirring, centrifuged, washed, and dried to produce a modified surface-deposited powder. S3 organic resin loading: The modified surface deposition powder was added to water, formaldehyde, melamine was added, heated and stirred to mix, citric acid and polyvinyl alcohol were added, the reaction was stirred and kept warm, filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin; S4. Loading of zinc tungstate: The surface deposition powder loaded with an organic resin is added to water, zinc salt is added, stirred and mixed, sodium tungstate is added, hydrothermal reaction is performed, filtered, washed, and dried to obtain a surface deposition powder loaded; S5. Preparation of modified alumina-based mullite: The surface-deposited powder is heated and calcined under an inert gas protection to obtain modified alumina-based mullite.

[0007] As a further improvement of the present invention, the mass ratio of the alumina-based mullite powder with a particle size of ≦3 mm and the alumina-based mullite fine powder with a mesh size of 300-400 mesh in step S1 is 3-5:1-2; the concentration of the diamond suspension in step S2 is 1-2wt%, the reaction gas sources of the surface chemical vapor deposition are hydrogen and methane, the hydrogen flow rate is 350-450 mL / min, the methane flow rate is 20-40 mL / min, the microwave power is 8-10kW, the deposition time is 1-3h, the pH value of the Tris-HCl solution is 8.5-9.5, the mass ratio of the surface deposition powder and dopamine hydrochloride is 10:2-3, the temperature of the heating and stirring reaction is 40-50°C, and the time is 3-5h.

[0008] As a further improvement of the present invention, in step S3, the mass ratio of the modified surface deposition powder, formaldehyde, melamine, citric acid and polyvinyl alcohol is 10:2-4:2-4:0.1-0.3:0.4-0.7, the heating temperature is 75-85° C., and the insulation stirring reaction time is 10-20 minutes.

[0009] As a further improvement of the present invention, in step S4, the mass ratio of the surface-deposited powder loaded with the organic resin to the zinc salt is 10:1-2, the molar amounts of the zinc salt and sodium tungstate are equal, the zinc salt is at least one of zinc chloride, zinc sulfate, and zinc nitrate, the hydrothermal reaction temperature is 175-185° C., and the reaction time is 5-7 h.

[0010] As a further improvement of the present invention, the heating and calcining in step S5 is performed at a temperature of 1600-1800° C. and for a time of 1-3 hours.

[0011] As a further improvement of the present invention, the preparation method of the modified andalusite is as follows: Adding andalusite powder into ethanol, adding aluminum isopropoxide and ethyl orthosilicate, dropping ammonia water, stirring to react, filtering, washing, drying, calcining, and ball milling to prepare modified andalusite.

[0012] As a further improvement of the present invention, the mass ratio of the andalusite powder, aluminum isopropoxide, ethyl orthosilicate and ammonia water is 12-15:3-5:4-7:5-10, the calcination temperature is 500-700° C., the time is 1-3 h, and the ball milling time is 1-2 h.

[0013] As a further improvement of the present invention, the binder is polyvinyl alcohol.

[0014] The present invention further provides a method for preparing the above-mentioned push plate for sintering a hard carbon negative electrode, comprising the following steps: (1) Treatment of the binder: Prepare the binder into a 10-15 wt% aqueous solution; (2) Mixing: Put various raw materials into the mixer according to the mass percentage, add the binder aqueous solution, and mix them evenly; (3) Molding: The prepared material is weighed according to the weight of the blank and poured into the mold, and then molded using a vibration molding machine or a hydraulic press; (4) Drying: The formed green body is naturally dried for 1-2 days, and then placed in a drying kiln for drying at 100℃-150℃ for 12-24 hours; (5) Firing: After drying, keep the temperature at 1400-1450℃ for 4-8 hours under the protection of inert gas to obtain a push plate for sintering the hard carbon negative electrode.

[0015] The present invention has the following beneficial effects: 1. Alumina-based mullite, with well-developed mullite as the main crystal phase, has good creep resistance and thermal shock resistance. The raw material contains about 3% Fe2O3 and TiO2, which promotes sintering, strengthens the bonding force between fine powder and particles, improves the high-temperature performance of the push plate, and enables the push plate to be sintered at a lower temperature, saving energy; The present invention mixes alumina-based mullite of different particle sizes to achieve a combination of coarse and fine particles. The alumina-based mullite powder with a smaller particle size of ≦3mm has a larger specific surface area. A larger specific surface area means a higher surface energy of the particles, which makes it easier for them to react and diffuse with other substances or their own particles during the sintering process. Compared with mullite powder with a particle size of ≦3mm, the 300-400 mesh fine powder has a smaller particle size and can be further filled into the smaller pores of the push plate. It can enter the tiny gaps that have not yet been filled in the skeleton constructed by particles with a particle size of ≦3mm, just like adding finer powdered materials to concrete filled with fine sand. This further reduces the porosity of the push plate and makes it more dense, thereby greatly enhancing the mechanical strength of the push plate, making it less likely to crack or be damaged during repeated use and high-temperature sintering.

[0016] The surface is coated with a dense diamond film deposited by chemical vapor deposition, with a hardness close to that of natural diamond. It has excellent properties such as low friction coefficient, good self-lubricating properties and high chemical stability. It is an excellent wear-resistant, friction-reducing and protective material. At the same time, after being modified with polydopamine, the surface has good affinity with formaldehyde and melamine, and can react in situ to form an organic resin coating. Then, after zinc ions are adsorbed on the surface, an in-situ hydrothermal reaction is performed to produce zinc tungstate. Under high-temperature calcination, the organic resin is pyrolyzed and vaporized to produce CO and NH3. As reducing gases and carbon sources, they can promote the reduction of zinc tungstate to WC and reduce Zn ions to Zn single-atom metal. As a catalyst, CO serves as a carbon source, and self-catalyzed in-situ deposition of carbon nanotubes is generated. As a result, a diamond-WC-carbon nanotube layer is loaded on the alumina-based mullite surface. Through interface bridging and crack deflection, the fracture toughness is improved, while the thermal conductivity is enhanced, and the push plate temperature gradient and thermal stress are reduced.

[0017] 2. SiC has extremely high mechanical strength and wear resistance. It is partially oxidized at high temperatures to form a dense layer on the push plate surface, further improving wear resistance. 3. Adding an appropriate amount of modified andalusite converts it into mullite and high-silica glass phases at high temperatures, improving thermal shock resistance. This invention modifies andalusite through a sol-gel reaction, significantly enhancing its mechanical properties and high-temperature resistance. This significantly increases thermal conductivity, while also improving surface hardness and wear resistance, as well as high-temperature stability and creep resistance. 4. The high-silicon glass phase reacts with alumina powder to form secondary mullite, which promotes the sintering between fine powder and particles, enhances mechanical properties, and gives the push plate excellent creep resistance; Therefore, the high-temperature push plate prepared by the present invention has excellent wear resistance, creep resistance and thermal shock resistance, good thermal conductivity, good mechanical properties, and good resistance to oxidation damage. It can well match the sintering of hard carbon negative electrode materials and has good application prospects. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] Alumina-based mullite, Al2O3 content ≥70%, with mullite as the primary crystalline phase ≥90%. Andalusite, Al2O3 content ≥59%, Fe2O3 content ≤1%. SiC powder, SiC content ≥97%. Alumina micropowder, D50 ≤2 μm, Al2O3 content ≥99.5%. Kaolin, D50 ≤45 μm, Al2O3 content ≥30%.

[0020] Preparation Example 1 Preparation of modified alumina-based mullite

[0021] Here’s how: S1 mixed powder: 3g particle size ≦3mm alumina-based mullite powder and 1g mesh number 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface Deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, ultrasonically shaken in a 1wt% diamond suspension for 30 minutes, then ultrasonically cleaned in alcohol for 20 minutes, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. 10g of the surface-deposited powder was added to 150mL of Tris-HCl solution (pH=8.5), followed by 2g of dopamine hydrochloride. The mixture was heated to 40°C, stirred for 3 hours, centrifuged, washed, and dried to produce a modified surface-deposited powder. The reaction gas sources for the surface chemical vapor deposition are hydrogen and methane, with a hydrogen flow rate of 350 mL / min, a methane flow rate of 20 mL / min, a microwave power of 8 kW, and a deposition time of 1 h; S3. Organic resin loading: 10 g of the modified surface deposition powder was added to 150 mL of water, 2 g of formaldehyde, and 2 g of melamine were added, heated to 75°C, and stirred for 30 min. 0.1 g of citric acid and 0.4 g of polyvinyl alcohol were added, and the mixture was stirred for 10 min. The mixture was filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin. S4. Loading of zinc tungstate: Add 10g of organic resin-loaded surface deposition powder to 150mL of water, add 1g of zinc chloride, stir and mix thoroughly, add sodium tungstate in an amount equivalent to the zinc salt, and hydrothermally react at 175°C for 5h. Filter, wash, and dry to obtain the loaded surface deposition powder. S5. Preparation of modified alumina-based mullite: The surface-deposited powder was heated to 1600° C. and calcined for 1 h under nitrogen protection to obtain modified alumina-based mullite.

[0022] Preparation Example 2 Preparation of modified alumina-based mullite

[0023] Here’s how: S1 mixed powder: 5g particle size ≦3mm alumina-based mullite powder and 2g mesh size 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface Deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, ultrasonically shaken in a 2wt% diamond suspension for 30 minutes, then ultrasonically cleaned in alcohol for 20 minutes, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. 10g of the surface-deposited powder was added to 150mL of Tris-HCl solution (pH 9.5), 3g of dopamine hydrochloride was added, and the mixture was heated to 50°C, stirred for 5 hours, centrifuged, washed, and dried to produce a modified surface-deposited powder. The reaction gas sources for the surface chemical vapor deposition are hydrogen and methane, with a hydrogen flow rate of 450 mL / min, a methane flow rate of 40 mL / min, a microwave power of 10 kW, and a deposition time of 3 h; S3. Organic resin loading: 10 g of the modified surface deposition powder was added to 150 mL of water, 4 g of formaldehyde, and 4 g of melamine were added, heated to 85°C, and stirred for 30 min. 0.3 g of citric acid and 0.7 g of polyvinyl alcohol were added, and the mixture was stirred for 20 min. The mixture was filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin. S4. Loading of zinc tungstate: 10 g of organic resin-loaded surface deposition powder was added to 150 mL of water, followed by 2 g of zinc sulfate. The mixture was stirred and mixed thoroughly. An amount of sodium tungstate equal to the amount of zinc salt was added. The mixture was hydrothermally reacted at 185°C for 7 h. The mixture was filtered, washed, and dried to obtain the loaded surface deposition powder. S5. Preparation of modified alumina-based mullite: The surface-deposited powder was heated to 1800° C. and calcined for 3 h under nitrogen protection to obtain modified alumina-based mullite.

[0024] Preparation Example 3 Preparation of modified alumina-based mullite

[0025] Here’s how: S1 mixed powder: 4g particle size ≦3mm alumina-based mullite powder and 1.5g mesh size 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface Deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, and ultrasonically vibrated in a 1.5wt% diamond suspension for 30 minutes. The mixture was then ultrasonically cleaned in alcohol for 20 minutes, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. 10g of the surface-deposited powder was added to 150mL of a pH 9 Tris-HCl solution, followed by 2.5g of dopamine hydrochloride. The mixture was heated to 45°C, stirred for 4 hours, centrifuged, washed, and dried to produce a modified surface-deposited powder. The reaction gas sources for the surface chemical vapor deposition are hydrogen and methane, with a hydrogen flow rate of 400 mL / min, a methane flow rate of 30 mL / min, a microwave power of 9 kW, and a deposition time of 2 h; S3. Organic resin loading: 10 g of the modified surface deposition powder was added to 150 mL of water, 3 g of formaldehyde, and 3 g of melamine were added, heated to 80°C, and stirred for 30 min. 0.2 g of citric acid and 0.55 g of polyvinyl alcohol were added, and the mixture was stirred for 150 min. The mixture was filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin. S4. Loading of zinc tungstate: 10 g of organic resin-loaded surface deposition powder was added to 150 mL of water, followed by 1.5 g of zinc nitrate. The mixture was stirred and mixed thoroughly. An amount of sodium tungstate equal to the amount of zinc salt was added. The mixture was hydrothermally reacted at 180°C for 6 h. The mixture was filtered, washed, and dried to obtain the loaded surface deposition powder. S5. Preparation of modified alumina-based mullite: The surface-deposited powder was heated to 1700° C. and calcined for 2 h under nitrogen protection to obtain modified alumina-based mullite.

[0026] Comparative Preparation Example 1

[0027] Compared with Preparation Example 3, the difference is that the mixed powder is a single alumina-based mullite powder with a particle size of ≦3 mm.

[0028] Comparative Preparation Example 2

[0029] Compared with Preparation Example 3, the difference is that the mixed powder is a single alumina-based mullite fine powder with a mesh size of 325 meshes.

[0030] Comparative Preparation Example 3

[0031] Compared with Preparation Example 3, the difference is that step S2 is not performed.

[0032] The details are as follows: S1 mixed powder: 4g particle size ≦3mm alumina-based mullite powder and 1.5g mesh size 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Organic resin loading: 10 g of the mixed powder was added to 150 mL of water, 3 g of formaldehyde and 3 g of melamine were added, heated to 80 ° C, stirred for 30 min, 0.2 g of citric acid and 0.55 g of polyvinyl alcohol were added, and the mixture was stirred for 150 min, filtered, washed, and dried to obtain a mixed powder loaded with an organic resin; S3. Loading of zinc tungstate: 10 g of the mixed powder of the loaded organic resin was added to 150 mL of water, 1.5 g of zinc nitrate was added, and the mixture was stirred and mixed. An amount of sodium tungstate and zinc salt was added, and the mixture was hydrothermally reacted at 180°C for 6 h. The mixture was filtered, washed, and dried to obtain the loaded mixed powder. S4. Preparation of modified alumina-based mullite: The loaded mixed powder was heated to 1700° C. and calcined for 2 h under nitrogen protection to obtain modified alumina-based mullite.

[0033] Comparative Preparation Example 4

[0034] Compared with Preparation Example 3, the difference is that step S3 is not performed.

[0035] The details are as follows: S1 mixed powder: 4g particle size ≦3mm alumina-based mullite powder and 1.5g mesh size 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface Deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, and ultrasonically vibrated in a 1.5wt% diamond suspension for 30 minutes. The mixture was then ultrasonically cleaned in alcohol for 20 minutes, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. 10g of the surface-deposited powder was added to 150mL of a pH 9 Tris-HCl solution, followed by 2.5g of dopamine hydrochloride. The mixture was heated to 45°C, stirred for 4 hours, centrifuged, washed, and dried to produce a modified surface-deposited powder. The reaction gas sources for the surface chemical vapor deposition are hydrogen and methane, with a hydrogen flow rate of 400 mL / min, a methane flow rate of 30 mL / min, a microwave power of 9 kW, and a deposition time of 2 h; S3. Loading of zinc tungstate: 10 g of the modified surface deposition powder was added to 150 mL of water, followed by 1.5 g of zinc nitrate. The mixture was stirred and mixed thoroughly. An amount of sodium tungstate equal to the amount of zinc salt was added. The mixture was hydrothermally reacted at 180°C for 6 h. The mixture was filtered, washed, and dried to obtain the loaded surface deposition powder. S4. Preparation of modified alumina-based mullite: The surface-deposited powder was heated to 1700° C. and calcined for 2 h under nitrogen protection to obtain modified alumina-based mullite.

[0036] Comparative Preparation Example 5

[0037] Compared with Preparation Example 3, the difference is that step S4 is not performed.

[0038] The details are as follows: S1 mixed powder: 4g particle size ≦3mm alumina-based mullite powder and 1.5g mesh size 325 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface Deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, and ultrasonically vibrated in a 1.5wt% diamond suspension for 30 minutes. The mixture was then ultrasonically cleaned in alcohol for 20 minutes, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. 10g of the surface-deposited powder was added to 150mL of a pH 9 Tris-HCl solution, followed by 2.5g of dopamine hydrochloride. The mixture was heated to 45°C, stirred for 4 hours, centrifuged, washed, and dried to produce a modified surface-deposited powder. The reaction gas sources for the surface chemical vapor deposition are hydrogen and methane, with a hydrogen flow rate of 400 mL / min, a methane flow rate of 30 mL / min, a microwave power of 9 kW, and a deposition time of 2 h; S3. Organic resin loading: 10 g of the modified surface deposition powder was added to 150 mL of water, 3 g of formaldehyde, and 3 g of melamine were added, heated to 80°C, and stirred for 30 min. 0.2 g of citric acid and 0.55 g of polyvinyl alcohol were added, and the mixture was stirred for 150 min. The mixture was filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin. S4. Preparation of modified alumina-based mullite: The surface-deposited powder loaded with an organic resin was heated to 1700° C. and calcined for 2 h under nitrogen protection to obtain modified alumina-based mullite.

[0039] Preparation Example 4 Preparation of modified andalusite

[0040] Here’s how:

[0041] 12 g of andalusite powder was added to ethanol, 3 g of aluminum isopropoxide and 4 g of ethyl orthosilicate were added, 5 g of ammonia water was added dropwise, and the mixture was stirred for 5 h, filtered, washed, dried, calcined at 500 ° C for 1 h, and ball milled for 1 h to obtain modified andalusite.

[0042] Preparation Example 5 Preparation of modified andalusite

[0043] Here’s how:

[0044] 15 g of andalusite powder was added to ethanol, 5 g of aluminum isopropoxide and 7 g of ethyl orthosilicate were added, 10 g of ammonia water was added dropwise, and the mixture was stirred for 7 h, filtered, washed, dried, calcined at 700 ° C for 3 h, and ball milled for 2 h to obtain modified andalusite.

[0045] Preparation Example 6 Preparation of Modified Andalusite

[0046] Here’s how:

[0047] 13 g of andalusite powder was added to ethanol, 4 g of aluminum isopropoxide and 5.5 g of ethyl orthosilicate were added, 7 g of ammonia water was added dropwise, and the mixture was stirred for 6 h. The mixture was filtered, washed, dried, calcined at 600 ° C for 2 h, and ball milled for 1.5 h to obtain modified andalusite.

[0048] Comparative Preparation Example 6

[0049] The difference compared with Preparation Example 6 is that aluminum isopropoxide is not added.

[0050] The details are as follows:

[0051] 13 g of andalusite powder was added to ethanol, 9.5 g of ethyl orthosilicate was added, 7 g of ammonia water was added dropwise, and the mixture was stirred for 6 h. The mixture was filtered, washed, dried, calcined at 600 ° C for 2 h, and ball milled for 1.5 h to obtain modified andalusite.

[0052] Comparative Preparation Example 7

[0053] Compared with Preparation Example 6, the difference is that no ethyl orthosilicate is added.

[0054] The details are as follows:

[0055] 13 g of andalusite powder was added to ethanol, 9.5 g of aluminum isopropoxide was added, 7 g of ammonia water was added dropwise, and the mixture was stirred for 6 h. The mixture was filtered, washed, dried, calcined at 600 ° C for 2 h, and ball milled for 1.5 h to obtain modified andalusite.

[0056] Example 1

[0057] This embodiment provides a push plate for sintering a hard carbon negative electrode.

[0058] Raw material composition (parts by weight): 30 parts of modified alumina-based mullite obtained in Preparation Example 1, 10 parts of modified andalusite obtained in Preparation Example 4, 10 parts of SiC powder, 10 parts of alumina powder, 3 parts of kaolin, and 5 parts of polyvinyl alcohol.

[0059] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 10 wt% aqueous solution; (2) Mixing: Put various raw materials into the mixer according to the mass percentage, add polyvinyl alcohol aqueous solution, and mix evenly; (3) Molding: The prepared material is weighed according to the weight of the blank, poured into the mold, and molded using a vibration molding machine; (4) Drying: The formed green body is naturally dried for 1 day, and then placed in a drying kiln for drying at 100°C for 12 hours; (5) Firing: After drying, keep the temperature at 1400℃ for 4 hours under nitrogen protection to obtain a push plate for sintering the hard carbon negative electrode.

[0060] Example 2

[0061] This embodiment provides a push plate for sintering a hard carbon negative electrode.

[0062] Raw material composition (parts by weight): 45 parts of modified alumina-based mullite obtained in Preparation Example 2, 20 parts of modified andalusite obtained in Preparation Example 5, 20 parts of SiC powder, 20 parts of alumina powder, 10 parts of kaolin, and 10 parts of polyvinyl alcohol.

[0063] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 15 wt% aqueous solution; (2) Mixing: Put various raw materials into the mixer according to the mass percentage, add polyvinyl alcohol aqueous solution, and mix evenly; (3) Molding: The prepared material is weighed according to the weight of the blank, poured into the mold, and molded using a hydraulic press; (4) Drying: The formed green body is naturally dried for 2 days, and then placed in a drying kiln for drying at 150°C for 12-24 hours; (5) Firing: After drying, keep the temperature at 1450℃ for 8 hours under nitrogen protection to obtain a push plate for sintering the hard carbon negative electrode.

[0064] Example 3

[0065] This embodiment provides a push plate for sintering a hard carbon negative electrode.

[0066] Raw material composition (parts by weight): 38 parts of modified alumina-based mullite obtained in Preparation Example 3, 15 parts of modified andalusite obtained in Preparation Example 6, 15 parts of SiC powder, 15 parts of alumina powder, 6 parts of kaolin, and 7 parts of polyvinyl alcohol.

[0067] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 12 wt% aqueous solution; (2) Mixing: Put various raw materials into the mixer according to the mass percentage, add polyvinyl alcohol aqueous solution, and mix evenly; (3) Molding: The prepared material is weighed according to the weight of the blank, poured into the mold, and molded using a vibration molding machine; (4) Drying: The formed green body is naturally dried for 1.5 days, and then placed in a drying kiln for 18 hours at 125°C; (5) Firing: After drying, keep the temperature at 1420℃ for 6 hours under nitrogen protection to obtain a push plate for sintering the hard carbon negative electrode.

[0068] Comparative Example 1

[0069] Compared with Example 3, the difference is that the modified alumina-based mullite is prepared by Comparative Preparation Example 1.

[0070] Comparative Example 2

[0071] Compared with Example 3, the difference is that the modified alumina-based mullite is prepared by Comparative Preparation Example 2.

[0072] Comparative Example 3

[0073] Compared with Example 3, the difference is that the modified alumina-based mullite is prepared by Comparative Preparation Example 3.

[0074] Comparative Example 4

[0075] Compared with Example 3, the difference is that the modified alumina-based mullite is prepared by Comparative Preparation Example 4.

[0076] Comparative Example 5

[0077] Compared with Example 3, the difference is that the modified alumina-based mullite is prepared by Comparative Preparation Example 5.

[0078] Comparative Example 6

[0079] Compared with Example 3, the difference is that the modified andalusite is prepared by Comparative Preparation Example 6.

[0080] Comparative Example 7

[0081] Compared with Example 3, the difference is that the modified andalusite is prepared by Comparative Preparation Example 7.

[0082] Test Example 1

[0083] The performance of the push plates for sintering the hard carbon negative electrodes prepared in Examples 1-3 and Comparative Examples 1-7 was tested. The results are shown in Table 1.

[0084] Table 1

[0085] It can be seen from the above table that the push plates for sintering hard carbon negative electrodes prepared in Examples 1-3 of the present invention have good comprehensive performance.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A push plate for sintering a hard carbon negative electrode, characterized in that: The invention is prepared from the following raw materials in parts by weight: 30-45 parts of modified alumina-based mullite, 10-20 parts of modified andalusite, 10-20 parts of SiC powder, 10-20 parts of alumina micropowder, 3-10 parts of kaolin and 5-10 parts of a binder.

2. The pusher plate for hard carbon negative electrode sintering according to claim 1, characterized in that: The preparation method of the modified alumina-based mullite is as follows: S1 mixed powder: The particle size ≦3mm alumina-based mullite powder and mesh size 300-400 mesh alumina-based mullite fine powder were mixed to obtain a mixed powder; S2. Surface deposition: The mixed powder was sequentially washed in acetone, alcohol, and deionized water, filtered, dried, ultrasonically shaken in a diamond suspension, then ultrasonically cleaned in alcohol, filtered, dried, and a diamond layer was chemically vapor deposited on the surface to produce a surface-deposited powder. The surface-deposited powder was added to a Tris-HCl solution, dopamine hydrochloride was added, the mixture was heated with stirring, centrifuged, washed, and dried to produce a modified surface-deposited powder. S3 organic resin loading: The modified surface deposition powder was added to water, formaldehyde, melamine was added, heated and stirred to mix, citric acid and polyvinyl alcohol were added, the reaction was stirred and kept warm, filtered, washed, and dried to obtain a surface deposition powder loaded with an organic resin; S4. Loading of zinc tungstate: The surface deposition powder loaded with an organic resin is added to water, zinc salt is added, stirred and mixed, sodium tungstate is added, hydrothermal reaction is performed, filtered, washed, and dried to obtain a surface deposition powder loaded; S5. Preparation of modified alumina-based mullite: The surface-deposited powder is heated and calcined under an inert gas protection to obtain modified alumina-based mullite.

3. The pusher plate for hard carbon negative electrode sintering according to claim 2, characterized in that: The mass ratio of the alumina-based mullite powder with a particle size of ≦3 mm and the alumina-based mullite fine powder with a mesh size of 300-400 mesh in step S1 is 3-5:1-2; the concentration of the diamond suspension in step S2 is 1-2wt%, the reaction gas sources of the surface chemical vapor deposition are hydrogen and methane, the hydrogen flow rate is 350-450 mL / min, the methane flow rate is 20-40 mL / min, the microwave power is 8-10kW, the deposition time is 1-3h, the pH value of the Tris-HCl solution is 8.5-9.5, the mass ratio of the surface deposition powder and dopamine hydrochloride is 10:2-3, the temperature of the heating and stirring reaction is 40-50°C, and the time is 3-5h.

4. The pusher plate for hard carbon negative electrode sintering according to claim 2, characterized in that: In step S3, the mass ratio of the modified surface deposition powder, formaldehyde, melamine, citric acid and polyvinyl alcohol is 10:2-4:2-4:0.1-0.3:0.4-0.7, the heating temperature is 75-85° C., and the heat preservation and stirring reaction time is 10-20 minutes.

5. The pusher plate for hard carbon negative electrode sintering according to claim 2, characterized in that: In step S4, the mass ratio of the surface deposition powder loaded with organic resin and the zinc salt is 10:1-2, the molar amounts of the zinc salt and sodium tungstate are equal, the zinc salt is at least one of zinc chloride, zinc sulfate, and zinc nitrate, the hydrothermal reaction temperature is 175-185° C., and the time is 5-7 hours.

6. The pusher plate for hard carbon negative electrode sintering according to claim 2, characterized in that: The heating and calcining in step S5 is performed at a temperature of 1600-1800° C. and for a time of 1-3 hours.

7. The pusher plate for hard carbon negative electrode sintering according to claim 1, characterized in that: The preparation method of the modified andalusite is as follows: Adding andalusite powder into ethanol, adding aluminum isopropoxide and ethyl orthosilicate, dropping ammonia water, stirring to react, filtering, washing, drying, calcining, and ball milling to prepare modified andalusite.

8. The pusher plate for hard carbon negative electrode sintering according to claim 7, characterized in that: The mass ratio of the andalusite powder, aluminum isopropoxide, ethyl orthosilicate and ammonia water is 12-15:3-5:4-7:5-10, the calcination temperature is 500-700° C., the calcination time is 1-3 hours, and the ball milling time is 1-2 hours.

9. The pusher plate for sintering hard carbon negative electrode according to claim 1, characterized in that: The binder is polyvinyl alcohol.

10. A method for preparing a push plate for sintering a hard carbon negative electrode according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Treatment of the binder: Prepare the binder into a 10-15 wt% aqueous solution; (2) Mixing: Put various raw materials into the mixer according to the mass percentage, add the binder aqueous solution, and mix them evenly; (3) Molding: The prepared material is weighed according to the weight of the blank and poured into the mold, and then molded using a vibration molding machine or a hydraulic press; (4) Drying: The formed green body is naturally dried for 1-2 days, and then placed in a drying kiln for drying at 100℃-150℃ for 12-24 hours; (5) Firing: After drying, keep the temperature at 1400-1450℃ for 4-8 hours under the protection of inert gas to obtain a push plate for sintering the hard carbon negative electrode.

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