Uv light-cured, solvent-free type nickel inner electrode paste, and preparation method and application thereof

Abstract

The application discloses a preparation method of a UV photocuring, solvent-free type nickel inner electrode paste, and specifically comprises the following steps: step 1, preparing acrylic modified cellulose microfibril; step 2, synthesizing a UV photocuring resin; step 3, synthesizing a nickel complex; step 4, preparing a nickel inner electrode paste according to the products obtained in steps 1-3; and step 5, preparing a ceramic paste according to the product obtained in step 4. The application further discloses the UV photocuring, solvent-free type nickel inner electrode paste and application thereof in multilayer ceramic capacitors. The electrode paste prepared by the application does not need to remove solvent by heating, avoids the problem of uneven solvent drying, and improves the yield and performance of devices.

Description

Technical Field

[0001] This invention belongs to the field of multilayer ceramic capacitor technology, and relates to UV-curable, solvent-free nickel internal electrode paste. This invention also relates to the preparation method and application of UV-curable, solvent-free nickel internal electrode paste. Background Technology

[0002] Multilayer ceramic capacitors (MLCCs) have a wide range of applications, including electronic circuits, medical electronics, and aerospace. The core components of a multilayer ceramic capacitor include a ceramic dielectric, internal electrodes, and terminal electrodes. It's important to note that the structure of a multilayer ceramic capacitor typically involves hundreds or thousands of layers formed by cross-stacking of the ceramic dielectric and internal electrodes. Therefore, all ceramic and electrode materials, as well as the molding process, significantly impact the device's production efficiency, performance, and yield. For example, when preparing a single-layer green embryo from the internal electrode slurry and ceramic dielectric, the green embryo needs to undergo drying to evaporate the solvent. The surface layer dries quickly, making it difficult to ensure uniformity in the green embryo drying rate, which will affect the device's production efficiency, yield, and performance. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing UV-curable, solvent-free nickel internal electrode paste. The electrode paste prepared by this method does not require heating to remove the solvent, thus avoiding the problem of uneven solvent drying and improving device yield and performance.

[0004] The second objective of this invention is to provide a UV-curable, solvent-free nickel internal electrode paste.

[0005] The third objective of this invention is to provide an application of UV-curable, solvent-free nickel internal electrode paste.

[0006] The first technical solution adopted in this invention is a method for preparing UV-curable, solvent-free nickel internal electrode paste, which specifically includes the following steps:

[0007] Step 1: Prepare acrylic acid-modified cellulose microfibers; Step 2: Synthesize UV-curable resin; Step 3: Synthesize the nickel complex; Step 4: Prepare nickel internal electrode slurry based on the products obtained in steps 1 to 3.

[0008] The first technical solution of this invention is further characterized by: The specific process of step 1 is as follows: Disperse 1-2 g of cellulose microfibrils in 100-200 mL of dimethyl sulfoxide solution and stir for 60-70 min; then add 0.85-1.7 mL of 2-bromoethyl acrylate and heat to 60-70 °C. oReact at C for 6-8 hours; then add 1-2 mL of pyridine as an acid-binding agent and 0.5-1 mL of 2-bromoethyl acrylate as a reaction starter to carry out a deep reaction; after the reaction is complete, filter to obtain modified cellulose microfibrils, then wash alternately with 100-200 mL of ethanol and 100-200 mL of water, repeating three times; place the washed product in an oven at 45-50°C. o After drying at C overnight, acrylic acid-modified cellulose microfibers are obtained.

[0009] Step 2 is as follows: Take 5-10 mL of diethylene glycol monoacrylate and 5-10 mL of isobornyl acrylate and stir at room temperature for 5-10 min. Then add 20-40 mg of dodecyl mercaptan and 5-10 mg of benzoyl peroxide and stir at room temperature for 15-25 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65-75°C. o C. Connect the constant pressure dropping funnel to the reaction flask and add the mixture dropwise over 1-2 hours. After the addition is complete, continue stirring for 20-30 minutes. Then, lower the reaction temperature to room temperature and add 10-20 mg of p-hydroxyanisole. Finally, add 3-6 mL of glycidyl methacrylate and 15-30 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50-60°C. o React at C for 1-2 hours, and control the viscosity at 10000-20000 cP to obtain UV-curable resin.

[0010] Step 3 is as follows: Disperse 10-20g of 2,4-pentanedione in 50-100mL of ethanol solution, then add 6.8-13.6g of sodium ethoxide and stir at room temperature for 30-40min; then add 3.2-6.4g of nickel chloride and continue stirring at room temperature for 30-40min; after the reaction is complete, add the reaction solution dropwise to 200-400mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter cake is then treated with 200-400 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40-50°C. o Drying at C for 12-24 hours yields the nickel complex.

[0011] The specific process of step 4 is as follows: Take 23-46g of UV-curable resin and 0.5-1g of tannic acid, then add 16-32g of nano-nickel powder and 95.5-191g of ultrafine nickel powder and stir thoroughly. Then add 5-10g of diethylene glycol monoacrylate for dilution, and continue to add 5-10g of nickel complex and 1.8-3.6g of acrylic acid modified cellulose microfibers. Continue to stir mechanically for 1-2 hours until the acrylic acid modified cellulose microfibers are completely dispersed. Then grind with a three-roll mill 3-5 times to obtain a uniform slurry. Finally, use diethylene glycol monoacrylate to adjust the viscosity of the slurry to control the viscosity at 20,000-40,000 cP. Then let the prepared slurry stand for 18-36 hours to eliminate internal stress and obtain the nickel internal electrode slurry.

[0012] In step 4, the particle size of the nano nickel powder is 30-60 nm; the particle size of the ultrafine nickel powder is 0.1-0.3 μm.

[0013] The second technical solution adopted in this invention is a UV-curable, solvent-free nickel internal electrode paste, which is prepared by the above-mentioned method for preparing UV-curable, solvent-free nickel internal electrode paste.

[0014] The third technical solution adopted in this invention is the application of UV-cured, solvent-free nickel internal electrode paste in multilayer ceramic capacitors.

[0015] The beneficial effects of this invention are as follows: (1) The UV (ultraviolet curing) photocurable internal electrode slurry and ceramic slurry of the present invention unify the preparation of single-layer green embryos of internal electrode slurry and ceramic slurry and UV curing and shaping, and both internal electrode slurry and ceramic slurry are solvent-free. On the one hand, there is no need for solvent evaporation process, which shortens the device process route; on the other hand, there is no need for heating to remove solvent, which avoids uneven drying.

[0016] (2) The present invention uses UV-curable internal electrode paste and ceramic paste, which eliminates the need for an additional greening and shaping process. At the same time, no solvent is added to the paste, eliminating the need for heating and drying, thus avoiding the impact of uneven heating and drying on the device. Attached Figure Description

[0017] Figure 1 These are the antioxidant results of Example 1 and Comparative Examples 1-4 of the preparation method of UV-curable, solvent-free nickel internal electrode paste of the present invention. Detailed Implementation

[0018] The following detailed description is provided in conjunction with specific implementation methods.

[0019] The method for preparing UV-curable, solvent-free nickel internal electrode paste of the present invention specifically includes the following steps: Step 1, preparing acrylic acid-modified cellulose microfibers, as detailed below: Take 1-2 g of cellulose microfibrils and disperse them in 100-200 mL of dimethyl sulfoxide solution, stirring for 60-70 min; then add 0.85-1.7 mL of 2-bromoethyl acrylate, and heat to 60-70 °C. o React at C for 6-8 hours; then add 1-2 mL of pyridine as an acid-binding agent and 0.5-1 mL of 2-bromoethyl acrylate as a reaction starter to carry out a deep reaction; after the reaction is complete, filter to obtain modified cellulose microfibrils, then wash alternately with 100-200 mL of ethanol and 100-200 mL of water, repeating three times; place the washed product in an oven at 45-50°C. o After drying at C overnight, acrylic acid-modified cellulose microfibers are obtained.

[0020] Step 2, the synthesis of UV-curable resin, is as follows: Take 5-10 mL of diethylene glycol monoacrylate and 5-10 mL of isobornyl acrylate and stir at room temperature for 5-10 min. Then add 20-40 mg of dodecyl mercaptan and 5-10 mg of benzoyl peroxide, and stir at room temperature for 15-25 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65-75°C. o C. Connect the constant pressure dropping funnel to the reaction flask and add the mixture dropwise over 1-2 hours. After the addition is complete, continue stirring for 20-30 minutes. Then, lower the reaction temperature to room temperature and add 10-20 mg of p-hydroxyanisole. Finally, add 3-6 mL of glycidyl methacrylate and 15-30 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50-60°C. o React at C for 1-2 hours, and control the viscosity at 10000-20000 cP to obtain UV-curable resin.

[0021] Step 3, synthesis of the nickel complex, is as follows: Disperse 10-20g of 2,4-pentanedione in 50-100mL of ethanol solution, then add 6.8-13.6g of sodium ethoxide and stir at room temperature for 30-40min; then add 3.2-6.4g of nickel chloride and continue stirring at room temperature for 30-40min; after the reaction is complete, add the reaction solution dropwise to 200-400mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter cake is then treated with 200-400 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40-50°C. o Dry at C for 12-24 hours.

[0022] Step 4, preparation of the nickel internal electrode paste, is as follows: Take 23-46g of UV-curable resin and 0.5-1g of tannic acid, then add 16-32g of nano-nickel powder (particle size 30-60nm) and 95.5-191g of ultrafine nickel powder (particle size 0.1-0.3um), and stir thoroughly. Then add 5-10g of diethylene glycol monoacrylate for dilution, and continue to add 5-10g of nickel complex and 1.8-3.6g of acrylic acid-modified cellulose microfibers. Continue to stir mechanically for 1-2 hours until the acrylic acid-modified cellulose microfibers are completely dispersed. Then grind with a three-roll mill 3-5 times to obtain a uniform slurry. Finally, use diethylene glycol monoacrylate to adjust the viscosity of the slurry to control it at 20000-40000cP. Then let the prepared slurry stand for 18-36 hours to eliminate internal stress and obtain the nickel internal electrode slurry for later use.

[0023] Step 5, preparation of ceramic slurry, is as follows: Add 20-40 mL of butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20-30 r / min, slowly add 1-2 g of fatty alcohol polyether phosphate. After stirring evenly, slowly add 20-40 g of UV-curable resin and stir for 12-24 h to obtain a transparent solution. Then add 5-10 g of polyethylene glycol and continue stirring evenly to obtain a UV-curable dispersion. Slowly add 110-220 g of BaTiO3 with a particle size of 100-300 nm to the UV-curable dispersion and stir at a low speed of 20-30 r / min for 2-3 h to form a paste. Stir at high speed under vacuum for 1-2 h, and then roll through a three-roll mill 3-5 times until the slurry fineness is <3µm. Let the obtained slurry stand for 24-36 h to obtain ceramic slurry for later use.

[0024] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50-100g of ceramic slurry, add 20-40mg of type 1173 photocuring agent, stir evenly, and then cast it on PET (polyethylene terephthalate) to form a film (casting speed is 0.3-0.5m / min). At the same time, it is photocured by irradiation with a 45-65W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6-8um, thus obtaining a ceramic green body.

[0025] The second step involves adding 20-30 mg of type 1173 photocuring agent to 50-100 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, simultaneously cured by irradiation with a 45-65W UV lamp to a film thickness of 2-3 μm, resulting in a single-layer green body, which takes 6-4 minutes. The single-layer green bodies are then stacked using a stacking machine, alternating between odd and even electrode layers, to a total of 100-300 layers. These layers are then hot-pressed at 60-70°C and 20-40 MPa for 30-60 minutes. Finally, the green body is laser-cut into 1.0 mm × 0.5 mm blocks perpendicular to the electrode direction using a laser cutter. These blocks are then placed in a muffle furnace and heated in air at 0.5-1... o The temperature is increased at a rate of C / min, and when it reaches 380-400°C, it is held for 1-2 hours. The temperature is then increased to 550-580°C and held for another 1-2 hours. The preform is then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2-4%) and H2+H2O (2-4%), and the temperature is increased from 550-580°C. o C starts with (3-5) o (C / min) Increase the temperature to 1200-1300 o C, keep warm for 2-3 hours. Then (1-2) o Cool to room temperature at 700-800°C (C / min). Immerse both ends of the sintered chip in conductive copper paste (CP-701BN) and sinter at 700-800°C for 10-20 min in N2 atmosphere to obtain a multilayer ceramic capacitor.

[0026] Example 1 Step 1, acrylic acid modified cellulose microfibers, as detailed below: Take 1 g of cellulose microfibrils and disperse them in 100 mL of dimethyl sulfoxide solution, stirring for 60 min. Then add 0.85 mL of 2-bromoethyl acrylate and heat to 60°C. o The reaction proceeded at C for 6 hours. Then, 1 mL of pyridine was added as an acid-binding agent and 0.5 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration, followed by washing with 100 mL of ethanol and 100 mL of water alternately, repeated three times. The washed product was then placed in an oven at 45°C. o After drying at C overnight, acrylic acid-modified cellulose microfibers are obtained.

[0027] Step 2, synthesis of UV-curable resin, is as follows: Take 5 mL of diethylene glycol monoacrylate and 5 mL of isobornyl acrylate and stir at room temperature for 5 min. Then add 20 mg of dodecyl mercaptan and 5 mg of benzoyl peroxide, and stir at room temperature for 15 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65°C.o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1 hour. After the addition is complete, continue stirring for 20 minutes. Then, lower the reaction temperature to room temperature and add 10 mg of p-hydroxyanisole. Finally, add 3 mL of glycidyl methacrylate and 15 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50°C. o After reacting at C for 1 hour, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0028] Step 3, synthesis of the nickel complex, is as follows: 10 g of 2,4-pentanedione is dispersed in 50 mL of ethanol solution, then 6.8 g of sodium ethoxide is added, and the mixture is stirred at room temperature for 30 min. Then 3.2 g of nickel chloride is added, and the mixture is stirred at room temperature for another 30 min. After the reaction is complete, the reaction solution is added dropwise to 200 mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter the cake using 200 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40°C. o Dry at C for 12 hours.

[0029] Step 4, preparation of the nickel internal electrode slurry, is as follows: Take 23g of UV-curable resin and 0.5g of tannic acid, then add 16g of nano-nickel powder (30nm particle size) and 95.5g of ultrafine nickel powder (0.1um particle size), and stir thoroughly. Then add 5g of diethylene glycol monoacrylate for dilution. Next, add 5g of nickel complex and 1.8g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 1 hour until the acrylic acid-modified cellulose microfibers are completely dispersed. Then, grind the mixture three times using a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then, let the prepared slurry stand for 18 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0030] Step 5, preparation of the ceramic slurry, is as follows: Add 20 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20 r / min, slowly add 1 g of fatty alcohol polyether phosphate and stir until homogeneous. Slowly add 20 g of UV-curable resin and stir for 12 h to obtain a transparent solution. Then add 5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 110 g of BaTiO3 with a particle size of 100 nm to the UV-curable dispersion. Stir at a low speed of 20 r / min for 2 h to form a paste. Further, stir at high speed under vacuum for 1 h, then roll three times using a three-roll mill until the slurry fineness is <3 µm. Let the obtained slurry stand for 24 h to obtain the ceramic slurry for later use.

[0031] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50g of ceramic slurry, add 20mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.3m / min). At the same time, it is photocured by irradiation with a 45W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6um, thus obtaining a ceramic green body.

[0032] The second step involves adding 20 mg of type 1173 photocuring agent to 50 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, simultaneously cured by irradiation with a 45W UV lamp to a film thickness of 2 μm, resulting in a single-layer green body, which takes 6 minutes. The single-layer green bodies are then stacked using a stacking machine, alternating between odd and even electrode layers, resulting in a total of 100 layers. These layers are then hot-pressed at 60°C and 20 MPa for 30 minutes. Finally, a laser cutter is used to cut the green body into 1.0 mm × 0.5 mm blocks perpendicular to the electrode direction. These blocks are then placed in a muffle furnace and heated in air at 0.5 mm... o The temperature was increased at a rate of C / min, and held at 380°C for 1 hour, then increased to 550°C and held for another hour. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2%) and H2+H2O (2%), and the temperature was increased from 550°C to 1 hour. o C starts with (3) o (C / min) Increase temperature to 1200 o C, keep warm for 2 hours. Then (1) o The sintered chip was cooled to room temperature at 700°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 700°C for 10 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0033] Example 2 Step 1, acrylic acid modified cellulose microfibers, as detailed below: Take 2g of cellulose microfibrils and disperse them in 200mL of dimethyl sulfoxide solution, stirring for 70min. Then add 1.7mL of 2-bromoethyl acrylate and heat to 70°C. o The reaction was carried out at C for 8 hours. Then, 2 mL of pyridine was added as an acid-binding agent and 1 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration, followed by washing with 200 mL of ethanol and 200 mL of water alternately, repeated three times. The washed product was then placed in an oven at 50°C. o C dry overnight.

[0034] Step 2, the synthesis of UV-curable resin, is as follows: Take 10 mL of diethylene glycol monoacrylate and 10 mL of isobornyl acrylate and stir at room temperature for 10 min. Then add 40 mg of dodecyl mercaptan and 10 mg of benzoyl peroxide, and stir at room temperature for 25 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask containing the stir bar in an oil bath and heat to 75°C. o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 2 hours. After the addition is complete, continue stirring for 30 minutes. Then, lower the reaction temperature to room temperature and add 20 mg of p-hydroxyanisole. Finally, add 6 mL of glycidyl methacrylate and 30 mg of tetrabutylammonium bromide to the reaction mixture and heat to 60°C. o After reacting at C for 2 hours, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0035] Step 3, synthesis of the nickel complex, is as follows: Disperse 20g of 2,4-pentanedione in 100mL of ethanol solution, then add 13.6g of sodium ethoxide and stir at room temperature for 40min. Then add 6.4g of nickel chloride and continue stirring at room temperature for another 40min. After the reaction is complete, add the reaction mixture dropwise to 400mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter cake is then treated with 400 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 50°C. o Dry at C for 24 hours.

[0036] Step 4, preparation of the nickel internal electrode paste, is as follows: Take 46g of UV-curable resin and 1g of tannic acid, then add 32g of nano-nickel powder (60nm particle size) and 191g of ultrafine nickel powder (0.3um particle size), and stir thoroughly. Then add 10g of diethylene glycol monoacrylate for dilution. Next, add 10g of nickel complex and 3.6g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 2 hours until the acrylic acid-modified cellulose microfibers are completely dispersed. Then, grind the mixture five times using a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000 and 40,000 cP. Then, let the prepared slurry stand for 36 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0037] Step 5, preparation of the ceramic slurry, is as follows: Add 40 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 30 r / min, slowly add 2 g of fatty alcohol polyether phosphate and stir until homogeneous. Slowly add 40 g of UV-curable resin and stir for 24 h to obtain a transparent solution. Then add 10 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 220 g of BaTiO3 with a particle size of 300 nm to the UV-curable dispersion. Stir at a low speed of 30 r / min for 3 h to form a paste. Further, stir at high speed under vacuum for 2 h, then roll the paste 5 times using a three-roll mill until the fineness is <3 µm. Let the resulting paste stand for 36 h to obtain the ceramic slurry for later use.

[0038] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 100g of ceramic slurry, add 40mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.5m / min). At the same time, it is photocured by irradiation with a 65W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 8um, thus obtaining a ceramic green body.

[0039] The second step involves adding 30 mg of type 1173 photocuring agent to 100 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, and simultaneously photocured by irradiation with a 65W UV lamp to a film thickness of 3 μm, resulting in a single-layer green body, which takes 4 minutes. The single-layer green bodies are then stacked using a stacking machine, with alternating odd and even electrode layers, resulting in a total of 300 layers. These layers are then hot-pressed at 70°C and 40 MPa for 60 minutes. Finally, a laser cutter is used to cut the green body into 1.0 mm × 0.5 mm block green bodies perpendicular to the electrode direction. The block green bodies are then placed in a muffle furnace and heated in air at 1... oThe temperature was increased at a rate of C / min, and when it reached 400°C, it was held for 2 hours. The temperature was then increased to 580°C and held for another 2 hours. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (4%) and H2+H2O (4%), and the temperature was increased from 580°C to 400°C. o C starts with (5) o (C / min) Increase temperature to 1300 o C, keep warm for 3 hours. Then (2) o The sintered chip was cooled to room temperature at 800°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 800°C for 20 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0040] Example 3 Step 1, preparing acrylic acid-modified cellulose microfibers, as detailed below: Take 1.5 g of cellulose microfibrils and disperse them in 150 mL of dimethyl sulfoxide solution, stirring for 65 min. Then add 1.27 mL of 2-bromoethyl acrylate and heat to 65°C. o The reaction was carried out at C for 7 hours. Then, 1.6 mL of pyridine was added as an acid-binding agent and 0.75 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration and then washed alternately with 150 mL of ethanol and 150 mL of water, repeated three times. The washed product was then placed in an oven at 47°C. o C dry overnight.

[0041] Step 2, the synthesis of UV-curable resin, is as follows: Take 7.5 mL of diethylene glycol monoacrylate and 7.5 mL of isobornyl acrylate and stir at room temperature for 7.5 min. Then add 30 mg of dodecyl mercaptan and 7.5 mg of benzoyl peroxide, and stir at room temperature for 20 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 70°C. o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1.5 hours. After the addition is complete, continue stirring for 25 minutes. Then, lower the reaction temperature to room temperature and add 15 mg of p-hydroxyanisole. Finally, add 4.5 mL of glycidyl methacrylate and 22.5 mg of tetrabutylammonium bromide to the reaction mixture and heat to 55°C. o After reacting at C for 1.5 hours, the viscosity is controlled at 10,000-20,000 cP to obtain a UV-curable resin.

[0042] Step 3, synthesis of the nickel complex, is as follows: Disperse 15g of 2,4-pentanedione in 75mL of ethanol solution, then add 10.2g of sodium ethoxide and stir at room temperature for 35min. Then add 4.8g of nickel chloride and continue stirring at room temperature for another 35min. After the reaction is complete, add the reaction mixture dropwise to 300mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter cake is then treated with 300 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 45°C. o Dry at C for 18 hours.

[0043] Step 4, preparation of the nickel internal electrode paste, is as follows: Take 34.5g of UV-curable resin and 0.75g of tannic acid, then add 24g of nano-nickel powder (45nm particle size) and 143.25g of ultrafine nickel powder (0.2um particle size), and stir thoroughly. Then add 7.5g of diethylene glycol monoacrylate for dilution. Next, add 7.5g of nickel complex and 2.7g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 1.5h until the acrylic acid-modified cellulose microfibers are completely dispersed. Then, grind the mixture four times using a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then, let the prepared slurry stand for 24h to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0044] Step 5, preparation of the ceramic slurry, is as follows: Add 30 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 25 r / min, slowly add 1.5 g of fatty alcohol polyether phosphate and stir until homogeneous. Slowly add 30 g of UV-curable resin and stir for 18 h to obtain a transparent solution. Then add 7.5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 165 g of BaTiO3 with a particle size of 200 nm to the UV-curable dispersion. Stir at a low speed of 25 r / min for 2.5 h to form a paste. Further, stir at high speed under vacuum for 1.5 h, then roll the paste four times using a three-roll mill until the fineness is <3 µm. Let the resulting paste stand for 30 h to obtain the ceramic slurry for later use.

[0045] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 75g of ceramic slurry, add 30mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.4m / min). At the same time, it is photocured by irradiation with a 55W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 7um, thus obtaining a ceramic green body.

[0046] The second step involves adding 25 mg of type 1173 photocuring agent to 75 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, simultaneously cured by irradiation with a 55W UV lamp to a film thickness of 2.5 μm, resulting in a single-layer green body, which takes 5 minutes. The single-layer green bodies are then stacked using a stacking machine, alternating between odd and even electrode layers, resulting in a total of 200 layers. These layers are then hot-pressed at 65°C and 30 MPa for 45 minutes. Finally, a laser cutter is used to cut the green body into 1.0 mm × 0.5 mm blocks perpendicular to the electrode direction. These blocks are then placed in a muffle furnace and heated in air at 0.75°C. o The temperature was increased at a rate of C / min, and when it reached 390°C, it was held for 1.5 hours. The temperature was then increased to 565°C and held for another 1.5 hours. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (3%) and H2+H2O (3%), and the temperature was increased from 565°C to 565°C. o C starts with (4) o (C / min) Increase the temperature to 1250 o C, keep warm for 2.5 hours. Then (1.5) o The sintered chip was cooled to room temperature at 750°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 750°C for 15 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0047] Comparative Example 1 (Ni internal electrode slurry, which was replaced by thermosetting instead of UV curing, resulting in a longer green preparation time. Due to the thermal expansion of the resin in the thermosetting device, the product yield and performance decreased.) Step 1, acrylic acid-modified cellulose microfibers, is as follows: Take 1g of cellulose microfibers and disperse them in 100mL of dimethyl sulfoxide solution, stirring for 60min. Then add 0.85mL of 2-bromoethyl acrylate and heat to 60°C. o The reaction proceeded at C for 6 hours. Then, 1 mL of pyridine was added as an acid-binding agent and 0.5 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration, followed by washing with 100 mL of ethanol and 100 mL of water alternately, repeated three times. The washed product was then placed in an oven at 45°C. o After drying at C overnight, acrylic acid-modified cellulose microfibers are obtained.

[0048] Step 2, synthesis of UV-curable resin, is as follows: Take 5 mL of diethylene glycol monoacrylate and 5 mL of isobornyl acrylate and stir at room temperature for 5 min. Then add 20 mg of dodecyl mercaptan and 5 mg of benzoyl peroxide, and stir at room temperature for 15 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65°C. o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1 hour. After the addition is complete, continue stirring for 20 minutes. Then, lower the reaction temperature to room temperature and add 10 mg of p-hydroxyanisole. Finally, add 3 mL of glycidyl methacrylate and 15 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50°C. o After reacting at C for 1 hour, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0049] Step 3, synthesis of the nickel complex, is as follows: 10 g of 2,4-pentanedione is dispersed in 50 mL of ethanol solution, then 6.8 g of sodium ethoxide is added, and the mixture is stirred at room temperature for 30 min. Then 3.2 g of nickel chloride is added, and the mixture is stirred at room temperature for another 30 min. After the reaction is complete, the reaction solution is added dropwise to 200 mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter the cake using 200 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40°C. o Dry at C for 12 hours.

[0050] Step 4, preparation of the nickel internal electrode slurry, is as follows: Take 23g of UV-curable resin and 0.5g of tannic acid, then add 16g of nano-nickel powder (30nm particle size) and 95.5g of ultrafine nickel powder (0.1um particle size), and stir thoroughly. Then add 5g of diethylene glycol monoacrylate for dilution. Next, add 5g of nickel complex and 1.8g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 1 hour until the acrylic acid-modified cellulose microfibers are completely dispersed. Then, grind the mixture three times using a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then, let the prepared slurry stand for 18 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0051] Step 5, preparation of the ceramic slurry, is as follows: Add 20 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20 r / min, slowly add 1 g of fatty alcohol polyether phosphate and stir until homogeneous. Slowly add 20 g of UV-curable resin and stir for 12 h to obtain a transparent solution. Then add 5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 110 g of BaTiO3 with a particle size of 100 nm to the UV-curable dispersion. Stir at a low speed of 20 r / min for 2 h to form a paste. Further, stir at high speed under vacuum for 1 h, then roll three times using a three-roll mill until the slurry fineness is <3 µm. Let the obtained slurry stand for 24 h to obtain the ceramic slurry for later use.

[0052] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50g of ceramic slurry, add 20mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.3m / min). At the same time, it is photocured by irradiation with a 45W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6um, thus obtaining a ceramic green body.

[0053] The second step involves adding 20 mg of azobisisobutyronitrile (AIBN) to 50 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, which is then heated to 80°C. o Curing at C for 20 minutes yielded a 2µm film thickness, resulting in a single-layer green preform, taking a total of 23 minutes. The single-layer green preforms were then stacked using a stacking machine, with alternating odd and even electrode layers, resulting in a total of 100 layers. The preforms were then hot-pressed at 60°C and 20MPa for 30-60 minutes. Finally, a laser cutter was used to cut the preforms into 1.0 mm × 0.5 mm blocks perpendicular to the electrodes. These blocks were then placed in a muffle furnace and heated in air at 0.5-1... o The temperature was increased at a rate of C / min, and held at 380°C for 1 hour, then increased to 550°C and held for another hour. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2%) and H2+H2O (2%), and the temperature was increased from 550°C to 1 hour. o C starts with (3) o (C / min) Increase temperature to 1200 o C, keep warm for 2 hours. Then (1) o The sintered chip was cooled to room temperature at 700°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 700°C for 10 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0054] Comparative Example 2 (Cellulose microfibrils were not modified with acrylic acid, resulting in poor dispersibility, poor single-layer preformation, and poor device performance) Step 1, the synthesis of UV-curable resin, is as follows: Take 5 mL of diethylene glycol monoacrylate and 5 mL of isobornyl acrylate and stir at room temperature for 5 min. Then add 20 mg of dodecyl mercaptan and 5 mg of benzoyl peroxide and stir at room temperature for 15 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65°C. o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1 hour. After the addition is complete, continue stirring for 20 minutes. Then, lower the reaction temperature to room temperature and add 10 mg of p-hydroxyanisole. Finally, add 3 mL of glycidyl methacrylate and 15 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50°C. o After reacting at C for 1 hour, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0055] Step 2, synthesis of the nickel complex, is as follows: Disperse 10g of 2,4-pentanedione in 50mL of ethanol solution, then add 6.8g of sodium ethoxide and stir at room temperature for 30min. Then add 3.2g of nickel chloride and continue stirring at room temperature for another 30min. After the reaction is complete, add the reaction mixture dropwise to 200mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter the cake using 200 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40°C. o Dry at C for 12 hours.

[0056] Step 3, preparation of the nickel internal electrode paste, is as follows: Take 23g of UV-curable resin and 0.5g of tannic acid, then add 16g of nano-nickel powder (30nm particle size) and 95.5g of ultrafine nickel powder (0.1µm particle size), and stir thoroughly. Then add 5g of diethylene glycol monoacrylate for dilution. Next, add 5g of nickel complex and 1.8g of cellulose microfibers, and continue mechanical stirring for 1 hour until the acrylic-modified cellulose microfibers are completely dispersed. Then, grind the mixture three times using a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then, let the prepared slurry stand for 18 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0057] Step 4, preparation of the ceramic slurry, specifically: Add 20 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20 r / min, slowly add 1 g of fatty alcohol polyether phosphate and stir until homogeneous. Then slowly add 20 g of UV-curable resin and stir for 12 h to obtain a transparent solution. Next, add 5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 110 g of BaTiO3 with a particle size of 100 nm to the UV-curable dispersion. Stir at a low speed of 20 r / min for 2 h to form a paste. Further, stir at high speed under vacuum for 1 h, then roll the paste three times using a three-roll mill until the fineness is <3 µm. Let the resulting paste stand for 24 h to obtain the ceramic slurry for later use.

[0058] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50g of ceramic slurry, add 20mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.3m / min). At the same time, it is photocured by irradiation with a 45W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6um, thus obtaining a ceramic green body.

[0059] The second step involves adding 20 mg of type 1173 photocuring agent to 50 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, simultaneously cured by irradiation with a 45W UV lamp to a film thickness of 2 μm, resulting in a single-layer green body, which takes 6 minutes. The single-layer green bodies are then stacked using a stacking machine, alternating between odd and even electrode layers, resulting in a total of 100 layers. These layers are then hot-pressed at 60°C and 20 MPa for 30 minutes. Finally, a laser cutter is used to cut the green body into 1.0 mm × 0.5 mm blocks perpendicular to the electrode direction. These blocks are then placed in a muffle furnace and heated in air at 0.5 mm... o The temperature was increased at a rate of C / min, and held at 380°C for 1 hour, then increased to 550°C and held for another hour. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2%) and H2+H2O (2%), and the temperature was increased from 550°C to 1 hour. o C starts with (3) o (C / min) Increase temperature to 1200 o C, keep warm for 2 hours. Then (1) o The sintered chip was cooled to room temperature at 700°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 700°C for 10 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0060] Comparative Example 3 (Diethylene glycol butyl ether acetate, a commonly used solvent, was added to the nickel internal electrode paste. After UV curing, the single-layer green preform was easily deformed and could not be directly stacked. It needed to be heated and dried before stacking, resulting in poor device performance) Step 1, acrylic acid modified cellulose microfibers, as detailed below: Take 1 g of cellulose microfibrils and disperse them in 100 mL of dimethyl sulfoxide solution, stirring for 60 min. Then add 0.85 mL of 2-bromoethyl acrylate and heat to 60°C. o The reaction proceeded at C for 6 hours. Then, 1 mL of pyridine was added as an acid-binding agent and 0.5 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration, followed by washing with 100 mL of ethanol and 100 mL of water alternately, repeated three times. The washed product was then placed in an oven at 45°C. o C dry overnight.

[0061] Step 2, synthesis of UV-curable resin, is as follows: Take 5 mL of diethylene glycol monoacrylate and 5 mL of isobornyl acrylate and stir at room temperature for 5 min. Then add 20 mg of dodecyl mercaptan and 5 mg of benzoyl peroxide, and stir at room temperature for 15 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65°C. o C. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1 hour. After the addition is complete, continue stirring for 20 minutes. Then, lower the reaction temperature to room temperature and add 10 mg of p-hydroxyanisole. Finally, add 3 mL of glycidyl methacrylate and 15 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50°C. o After reacting at C for 1 hour, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0062] Step 3, synthesis of the nickel complex, is as follows: 10 g of 2,4-pentanedione is dispersed in 50 mL of ethanol solution, then 6.8 g of sodium ethoxide is added, and the mixture is stirred at room temperature for 30 min. Then 3.2 g of nickel chloride is added, and the mixture is stirred at room temperature for another 30 min. After the reaction is complete, the reaction solution is added dropwise to 200 mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter the cake using 200 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40°C. o Dry at C for 12 hours.

[0063] Step 4, preparation of the nickel internal electrode slurry, is as follows: Take 15g of diethylene glycol butyl ether acetate, 23g of UV-curable resin, and 0.5g of tannic acid. Then add 16g of nano-nickel powder (30nm particle size) and 95.5g of ultrafine nickel powder (0.1um particle size), and stir thoroughly. Add 5g of diethylene glycol monoacrylate for dilution. Continue to add 5g of nickel complex and 1.8g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 1 hour until the acrylic acid-modified cellulose microfibers are completely dispersed. Then grind three times with a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry with diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then let the prepared slurry stand for 18 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0064] Step 5, preparation of the ceramic slurry, is as follows: Add 20 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20 r / min, slowly add 1 g of fatty alcohol polyether phosphate and stir until homogeneous. Slowly add 20 g of UV-curable resin and stir for 12 h to obtain a transparent solution. Then add 5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 110 g of BaTiO3 with a particle size of 100 nm to the UV-curable dispersion. Stir at a low speed of 20 r / min for 2 h to form a paste. Further, stir at high speed under vacuum for 1 h, then roll three times using a three-roll mill until the slurry fineness is <3 µm. Let the obtained slurry stand for 24 h to obtain the ceramic slurry for later use.

[0065] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50g of ceramic slurry, add 20mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.3m / min). At the same time, it is photocured by irradiation with a 45W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6um, thus obtaining a ceramic green body.

[0066] The second step involves adding 20 mg of type 1173 photocuring agent to 50 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, and simultaneously photocured by irradiation with a 45W UV lamp to achieve a film thickness of 2 μm, resulting in a single-layer green body. The resulting green body is then subjected to 80°C photocuring. oUnder C conditions, the process took 20 minutes, with a total time of 26 minutes. Single-layer green preforms were stacked using a stacking machine, with alternating odd and even electrode layers, resulting in a total of 100 layers. These were then hot-pressed at 60°C and 20 MPa for 30-60 minutes. Afterward, a laser cutter was used to cut the preforms into 1.0 mm × 0.5 mm blocks perpendicular to the electrodes. The blocks were then placed in a muffle furnace and heated in air at 0.5... o The temperature was increased at a rate of C / min, and held at 380°C for 1 hour, then increased to 550°C and held for another hour. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2%) and H2+H2O (2%), and the temperature was increased from 550°C to 1 hour. o C starts with (3) o (C / min) Increase temperature to 1200 o C, keep warm for 2 hours. Then (1) o The sintered chip was cooled to room temperature at 700°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 700°C for 10 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0067] Comparative Example 4 (When nickel complex was replaced with nickel chloride during the preparation of nickel internal electrode paste, it could not be dispersed in the paste, resulting in increased debinding temperature and deterioration of device performance) Step 1, acrylic acid modified cellulose microfibers, as detailed below: Take 1 g of cellulose microfibrils and disperse them in 100 mL of dimethyl sulfoxide solution, stirring for 60 min. Then add 0.85 mL of 2-bromoethyl acrylate and heat to 60°C. o The reaction proceeded at C for 6 hours. Then, 1 mL of pyridine was added as an acid-binding agent and 0.5 mL of 2-bromoethyl acrylate as a reactant to allow for a deeper reaction. After the reaction was complete, the modified cellulose microfibrils were obtained by filtration, followed by washing with 100 mL of ethanol and 100 mL of water alternately, repeated three times. The washed product was then placed in an oven at 45°C. o C dry overnight.

[0068] Step 2, synthesis of UV-curable resin, is as follows: Take 5 mL of diethylene glycol monoacrylate and 5 mL of isobornyl acrylate and stir at room temperature for 5 min. Then add 20 mg of dodecyl mercaptan and 5 mg of benzoyl peroxide, and stir at room temperature for 15 min to obtain a mixture. Transfer the mixture into a constant pressure dropping funnel. Place the reaction flask with the stir bar in an oil bath and heat to 65°C. oC. Connect the constant-pressure dropping funnel to the reaction flask and add the mixture dropwise over 1 hour. After the addition is complete, continue stirring for 20 minutes. Then, lower the reaction temperature to room temperature and add 10 mg of p-hydroxyanisole. Finally, add 3 mL of glycidyl methacrylate and 15 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50°C. o After reacting at C for 1 hour, the viscosity is controlled at 10000-20000 cP to obtain a UV-curable resin.

[0069] Step 3, preparation of the nickel internal electrode slurry: Take 23g of UV-curable resin and 0.5g of tannic acid, then add 16g of nano-nickel powder (30nm particle size) and 95.5g of ultrafine nickel powder (0.1um particle size), stir thoroughly, and then add 5g of diethylene glycol monoacrylate for dilution. Continue to add 5g of nickel chloride and 1.8g of acrylic acid-modified cellulose microfibers, and continue mechanical stirring for 1 hour until the acrylic acid-modified cellulose microfibers are completely dispersed. Then, grind three times with a three-roll mill to obtain a uniform slurry. Finally, adjust the viscosity of the slurry using diethylene glycol monoacrylate to control it between 20,000-40,000 cP. Then, let the prepared slurry stand for 18 hours to eliminate internal stress, obtaining the nickel internal electrode slurry for later use.

[0070] Step 4, preparation of the ceramic slurry, specifically: Add 20 mL of a butyl acrylate / diethylene glycol monoacrylate (v:v = 7:3) mixed solution to a stirrer. While stirring at a low speed of 20 r / min, slowly add 1 g of fatty alcohol polyether phosphate and stir until homogeneous. Then slowly add 20 g of UV-curable resin and stir for 12 h to obtain a transparent solution. Next, add 5 g of polyethylene glycol and continue stirring until homogeneous to obtain a UV-curable dispersion. Slowly add 110 g of BaTiO3 with a particle size of 100 nm to the UV-curable dispersion. Stir at a low speed of 20 r / min for 2 h to form a paste. Further, stir at high speed under vacuum for 1 h, then roll the paste three times using a three-roll mill until the fineness is <3 µm. Let the resulting paste stand for 24 h to obtain the ceramic slurry for later use.

[0071] The performance study of UV-curable, solvent-free nickel internal electrode paste is detailed below: The first step is to take 50g of ceramic slurry, add 20mg of 1173 type photocuring agent, stir evenly, and then cast it on PET to form a film (casting speed is 0.3m / min). At the same time, it is photocured by irradiation with a 45W ultraviolet lamp to obtain a ceramic dielectric film with a thickness of 6um, thus obtaining a ceramic green body.

[0072] The second step involves adding 20 mg of type 1173 photocuring agent to 50 g of nickel internal electrode paste. Then, the nickel internal electrode paste is screen-printed onto the surface of the ceramic green body, simultaneously cured by irradiation with a 45W UV lamp to a film thickness of 2 μm, resulting in a single-layer green body, which takes 6 minutes. The single-layer green bodies are then stacked using a stacking machine, alternating between odd and even electrode layers, resulting in a total of 100 layers. These layers are then hot-pressed at 60°C and 20 MPa for 30 minutes. Finally, a laser cutter is used to cut the green body into 1.0 mm × 0.5 mm blocks perpendicular to the electrode direction. These blocks are then placed in a muffle furnace and heated in air at 0.5 mm... o The temperature was increased at a rate of C / min, and held at 480°C for 1 hour, then increased to 600°C and held for another hour. The preform was then transferred to a tunnel furnace in an atmosphere of a mixture of N2+ (2%) and H2+H2O (2%), and the temperature was increased from 600°C to 600°C and held for another hour. o C starts with (3) o (C / min) Increase temperature to 1200 o C, keep warm for 2 hours. Then (1) o The sintered chip was cooled to room temperature at 700°C (C / min). Both ends of the sintered chip were immersed in conductive copper paste (CP-701BN) and sintered at 700°C for 10 min in an N2 atmosphere to obtain a multilayer ceramic capacitor.

[0073] Table 1 Performance results of Examples 1-3 and Comparative Examples 1-4

[0074] Laminate yield ≈ (Number of qualified laminates / Total number of laminates) × 100%. To test the oxidation resistance of the internal electrodes, the terminal electrodes of the multilayer ceramic capacitor were first stripped, then the remaining multilayer ceramic capacitor was crushed and ground into 300µm particles. Finally, thermogravimetric analysis was performed under the following conditions: a mixed atmosphere of O2 (20%) and N2 (80%), 5... o Heating rate (C / min)

[0075] Results Discussion Table 1 shows that the preparation time for single-layer green bodies in Examples 1-3 was relatively short, with Example 2 taking the shortest time at 4 minutes, mainly due to its fastest film casting speed. Meanwhile, Example 2 had a lower lamination-to-delamination yield because it had the highest number of layers (300), higher than Examples 1-2. It exhibited higher oxidation resistance (9.2-9.6%), primarily due to the excellent oxidation resistance of nickel itself. The residual carbon content (ppm) after debinding was 198-215 ppm. Results on capacitance and breakdown voltage showed that Example 2 had the highest capacitance and Example 1 the lowest, mainly because, with similar device structures, capacitance and breakdown voltage are positively correlated with the number of stacked layers. Example 2 had 300 stacked layers, while Example 1 only had 100 layers.

[0076] Figure 1 This presents the oxidation resistance results of Example 1 and Comparative Examples 1-4 of the preparation method of the UV-curable, solvent-free nickel internal electrode slurry of the present invention. In Comparative Example 1, the nickel internal electrode slurry was replaced by thermal curing instead of UV curing. Compared with Example 1, the green preparation time was extended by 23 min; due to the thermal expansion of the resin in the thermally cured device, the yield of the device decreased by 82%, and the oxidation resistance, capacitance, and breakdown voltage of the device all decreased. This may be due to the poor density of the subsequent electrodes caused by thermal expansion and contraction.

[0077] In Comparative Example 2, the cellulose microfibrils were not modified with acrylic acid. The surface of the cellulose microfibrils mainly consisted of hydrophilic hydroxyl functional groups, resulting in poor dispersibility in the organic matrix and poor single-layer preformation. The lamination yield, capacitance, oxidation resistance, breakdown voltage, and other indicators or properties all decreased; while the amount of residual carbon increased after debinding.

[0078] In Comparative Example 3, the addition of diethylene glycol butyl ether acetate, a commonly used solvent, to the nickel internal electrode slurry resulted in easy deformation of the monolayer green body after UV curing. This is because the presence of diethylene glycol butyl ether acetate prevents direct stacking; it requires heating and drying before stacking, significantly extending the preparation time of the monolayer green body to 26 minutes. This leads to a severe reduction in capacitance and breakdown voltage performance.

[0079] In Comparative Example 4, when nickel complex was replaced with nickel chloride during the preparation of nickel internal electrode slurry, it could not be dispersed in the slurry. The lack of catalytic effect of nickel complex led to an increase in the debinding temperature. At the same time, the inability of nickel complex to disperse in the slurry resulted in poor uniformity of the prepared monolayer green body, leading to poor performance in terms of oxidation resistance, capacitance, and breakdown voltage. The amount of residual carbon after debinding increased sharply.

[0080] Example 4 Compared with Example 1, the drying temperature in step 1 is 46°C, and the remaining steps are the same as in Example 1.

[0081] Example 5 Compared with Example 1, the heating temperature in the oil bath in step 2 is 68 degrees Celsius, and the remaining steps are the same as in Example 1.

[0082] Example 6 Compared with Example 1, the drying temperature in the oven in step 3 is 42°C and the drying time is 15 hours, while the remaining steps are the same as in Example 1.

Claims

1. A method for preparing UV-curable, solvent-free nickel internal electrode paste, characterized in that: Specifically, the steps include the following: Step 1: Prepare acrylic acid-modified cellulose microfibers; Step 2: Synthesize UV-curable resin; Step 3: Synthesize the nickel complex; Step 4: Prepare nickel internal electrode slurry based on the products obtained in steps 1 to 3.

2. The method for preparing UV-curable, solvent-free nickel internal electrode paste according to claim 1, characterized in that: The specific process of step 1 is as follows: Disperse 1-2 g of cellulose microfibrils in 100-200 mL of dimethyl sulfoxide solution and stir for 60-70 min; then add 0.85-1.7 mL of 2-bromoethyl acrylate and heat to 60-70 °C. o React at C for 6-8 hours; then add 1-2 mL of pyridine as an acid-binding agent and 0.5-1 mL of 2-bromoethyl acrylate as a reaction starter to carry out a deep reaction; after the reaction is complete, filter to obtain modified cellulose microfibrils, then wash alternately with 100-200 mL of ethanol and 100-200 mL of water, repeating three times; place the washed product in an oven at 45-50°C. o After drying at C overnight, acrylic acid-modified cellulose microfibers are obtained.

3. The method for preparing UV-curable, solvent-free nickel internal electrode paste according to claim 2, characterized in that: The specific process of step 2 is as follows: Take 5-10 mL of diethylene glycol monoacrylate and 5-10 mL of isobornyl acrylate and stir at room temperature for 5-10 min. Then add 20-40 mg of dodecyl mercaptan and 5-10 mg of benzoyl peroxide and stir at room temperature for 15-25 min to obtain a mixture. Pour the mixture into a constant pressure dropping funnel and place the reaction flask with a stir bar in an oil bath and heat to 65-75°C. o C. Connect the constant pressure dropping funnel to the reaction flask and add the mixture dropwise over 1-2 hours. After the addition is complete, continue stirring for 20-30 minutes. Then, lower the reaction temperature to room temperature and add 10-20 mg of p-hydroxyanisole. Finally, add 3-6 mL of glycidyl methacrylate and 15-30 mg of tetrabutylammonium bromide to the reaction mixture and heat to 50-60°C. o React at C for 1-2 hours, and control the viscosity at 10000-20000 cP to obtain UV-curable resin.

4. The method for preparing UV-curable, solvent-free nickel internal electrode paste according to claim 3, characterized in that: The specific process of step 3 is as follows: Take 10-20g of 2,4-pentanedione and disperse it in 50-100mL of ethanol solution, then add 6.8-13.6g of sodium ethoxide, and stir at room temperature for 30-40min; then add 3.2-6.4g of nickel chloride, and continue stirring at room temperature for 30-40min; after the reaction is complete, add the reaction solution dropwise to 200-400mL of 0. o In ice water at temperature C, a precipitate forms; collect the filter cake. Filter cake is then treated with 200-400 mL of 0... o Wash with ice water (C) three times to remove unreacted nickel chloride and sodium ethoxide. Place the collected solid product in an oven at 40-50°C. o Drying at C for 12-24 hours yields the nickel complex.

5. The method for preparing UV-curable, solvent-free nickel internal electrode paste according to claim 4, characterized in that: The specific process of step 4 is as follows: Take 23-46g of UV-curable resin and 0.5-1g of tannic acid, then add 16-32g of nano-nickel powder and 95.5-191g of ultrafine nickel powder and stir thoroughly. Then add 5-10g of diethylene glycol monoacrylate for dilution, and continue to add 5-10g of nickel complex and 1.8-3.6g of acrylic acid modified cellulose microfibers. Continue to stir mechanically for 1-2 hours until the acrylic acid modified cellulose microfibers are completely dispersed. Then grind with a three-roll mill 3-5 times to obtain a uniform slurry. Finally, use diethylene glycol monoacrylate to adjust the viscosity of the slurry to control the viscosity at 20,000-40,000 cP. Then let the prepared slurry stand for 18-36 hours to eliminate internal stress and obtain the nickel internal electrode slurry.

6. The method for preparing UV-curable, solvent-free nickel internal electrode paste according to claim 5, characterized in that: In step 4, the particle size of the nano-nickel powder is 30-60 nm; the particle size of the ultrafine nickel powder is 0.1-0.3 μm.

7. A UV-curable, solvent-free nickel internal electrode paste, prepared by the method described in any one of claims 1 to 6.

8. The application of the UV-curable, solvent-free nickel internal electrode paste according to claim 7 in multilayer ceramic capacitors.

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