Preparation method of single-walled carbon nanotube composite conductive nickel paste
By combining single-walled carbon nanotubes with nickel powder and using a non-toxic solvent system and microfluidic technology to prepare conductive nickel paste, the problems of conductivity and electrode continuity of the internal electrode electronic paste of nickel powder were solved, improving the conductivity and electrode continuity of MLCCs, and enhancing high-frequency performance and co-firing properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENYANG HUIJING NANOTECH CO LTD
- Filing Date
- 2026-05-09
- Publication Date
- 2026-07-21
AI Technical Summary
Existing nickel powder internal electrode electronic pastes have shortcomings in terms of conductivity, electrode continuity and co-firing performance, making it difficult to meet the high-performance requirements of MLCCs.
A conductive nickel paste with high conductivity, excellent electrode continuity, and good co-firing properties was prepared by combining single-walled carbon nanotubes with nickel powder, dispersing it in a non-toxic solvent system, and combining it with microfluidic technology.
It significantly improves the conductivity and electrode continuity of MLCCs, enhances high-frequency performance and co-firing properties, reduces contact resistance, and increases electrode density and flatness.
Smart Images
Figure CN122177655B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electronic paste technology, specifically relating to a method for preparing a single-walled carbon nanotube composite conductive nickel paste. Background Technology
[0002] Multilayer ceramic capacitors (MLCCs) are core components in the electronics and information industry, widely used in smartphones, automotive electronics, communication equipment, and industrial control. Their performance directly affects the stability and reliability of end products. The internal electrodes of an MLCC are crucial for energy storage and release, typically fabricated from internal electrode paste through screen printing, lamination, and sintering processes. The conductivity of the internal electrode paste directly determines the MLCC's equivalent series resistance (ESR), thus affecting the capacitor's frequency characteristics and energy efficiency. Conversely, the continuity, flatness, and co-firing compatibility of the internal electrodes with the ceramic dielectric determine the MLCC's capacitance, voltage rating, reliability, and miniaturization integration capabilities.
[0003] Currently, commercially available MLCC internal electrode pastes primarily use noble metals (such as silver and palladium) or their alloys (such as silver-palladium alloys) as the conductive phase. Silver paste has a high conductivity of approximately 6.3 × 10⁻⁶. 7 While possessing advantages such as low S / m and relatively low sintering temperature, its high cost and migration risk in high-temperature and high-humidity environments limit its application in high-end MLCCs. To reduce costs, base metal internal electrode (BME) pastes, especially nickel pastes, are preferred due to their abundant resources, low price, and conductivity of approximately 1.4 × 10⁻⁶. 7 With a acceptable S / m, it has become an important development direction for mid-to-low-end MLCCs and some high-end MLCCs.
[0004] However, pure nickel powder internal electrode pastes face severe challenges in achieving high conductivity and excellent electrode continuity: First, nickel's conductivity is only about 1 / 4 that of silver. To meet the low ESR requirements of MLCCs, the nickel powder content needs to be increased to build a denser conductive network. However, this leads to increased paste viscosity, poor printability, and defects such as pinholes and uneven thickness in the printed electrodes, damaging electrode continuity and affecting the capacitance consistency and withstand voltage of MLCCs. Second, nickel is easily oxidized during high-temperature sintering at 800℃-1000℃ in a reducing atmosphere. The resulting nickel oxide is an insulator, which significantly increases contact resistance, severely degrades conductivity, and may lead to poor bonding between the electrode and the ceramic dielectric interface. Third, the contact resistance between pure nickel powder particles is relatively large, and pores are easily formed inside the electrode, resulting in discontinuous current transmission paths and making it difficult to obtain ideal electrode continuity, thus limiting the high-frequency performance of MLCCs.
[0005] Therefore, in order to improve the performance of MLCCs and meet the development needs of miniaturization, high frequency and high reliability of electronic devices, it is now necessary to develop nickel internal electrode electronic pastes with high conductivity, excellent electrode continuity and good co-firing performance. Summary of the Invention
[0006] In view of the technical problems existing in the prior art, the present invention provides a method for preparing single-walled carbon nanotube composite conductive nickel paste. This single-walled carbon nanotube composite conductive nickel paste exhibits high conductivity, excellent electrode continuity, and good co-firing properties.
[0007] To achieve the above objectives, the present invention adopts the following technical solution.
[0008] A method for preparing a single-walled carbon nanotube composite conductive nickel paste includes the following steps:
[0009] Step 1: Dissolve PVB in terpineol and stir until homogeneous to obtain solution A;
[0010] Step 2: Dissolve the single-walled carbon nanotubes in solution A and stir until homogeneous to obtain solution B;
[0011] Step 3: Disperse solution B in a high-pressure homogenizer to obtain a single-walled carbon nanotube conductive slurry in a solvent system;
[0012] Step 4: Mix the single-walled carbon nanotube conductive slurry, organic solvent, dispersant, resin, thixotropic agent, and coupling agent in the solvent system, and stir until uniform to obtain a pre-dispersion.
[0013] Step 5: Take the pre-dispersed liquid, barium titanate powder, and nano nickel powder, and mix them in a degassing machine;
[0014] Step 6: Grind the well-mixed slurry on a three-roll mill to obtain the ground slurry;
[0015] Step 7: Homogenize the ground slurry multiple times on a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
[0016] Further, in step 1, the mass fraction of PVB is 0.4-1 part, the molecular weight of PVB is 25,000-40,000, and the mass fraction of terpineol is 99-99.6 parts.
[0017] Furthermore, in step 2, the mass fraction of single-walled carbon nanotubes is 0.2 to 1 part.
[0018] Furthermore, in step 3, the dispersion pressure is 80 MPa until D50 ≤ 4 μm.
[0019] Further, in step 4, the solvent system comprises 20-50 parts by mass of single-walled carbon nanotube conductive slurry; 40-65 parts by mass of organic solvent; 0.1-1 parts by mass of dispersant; 0.5-2 parts by mass of resin; 0.1-1 parts by mass of thixotropic agent; and 0.1-1 parts by mass of coupling agent.
[0020] Furthermore, in step 4, the organic solvent is one or a combination of several of the following: terpineol, butylcarbidol, solvent oil, diisononyl adipate, and 4-isopropyltoluene.
[0021] Furthermore, in step 4, the dispersant is one or a combination of oleamide, fatty acid alkylammonium salt, and sorbitan monooleate.
[0022] Furthermore, in step 4, the resin is one or a combination of several of ethyl cellulose, PVB, PVA, and epoxy resin.
[0023] Furthermore, in step 4, the thixotropic agent is one or a combination of hydrogenated castor oil, fumed silica, and polycaprolactone.
[0024] Furthermore, in step 4, the coupling agent is one or a combination of silane coupling agents and titanate coupling agents.
[0025] Furthermore, in step 4, the stirrer speed is 1000 rpm / min, and the stirring time is 1 hour.
[0026] Furthermore, in step 5, the pre-dispersion liquid comprises 35-50 parts by mass, the barium titanate powder comprises 9-13 parts by mass, and the nano-nickel powder comprises 40-50 parts by mass.
[0027] Furthermore, in step 5, the degassing machine rotates at 2000 rpm / min and the mixing time is 30 min.
[0028] Further, in step 6, the three-roll mill grinds the material at 300 rpm / min until the fineness is less than 2 μm.
[0029] Furthermore, in step 7, the homogenization pressure is 20,000 psi, and the homogenization is performed 3-5 times.
[0030] Compared with the prior art, the beneficial effects of the present invention are as follows.
[0031] 1. In the prior art, carbon nanotube slurries are aqueous or NMP systems, which cannot be compatible with the organic carrier of nickel paste for MLCCs. However, the present invention prepares a non-toxic and environmentally friendly solvent system carbon nanotube slurry, which can ensure that the carbon nanotubes have excellent dispersion and give full play to their high aspect ratio.
[0032] 2. In compound nickel paste, on the one hand, SWNTs (single-walled carbon nanotubes) can act as efficient "electronic wires," bridging the gaps between nickel powder particles, shortening the current transmission path, and reducing contact resistance, thereby significantly improving the conductivity of the composite paste. On the other hand, the "space-filling" and "network support" effects of SWNTs can effectively reduce microscopic pores and cracks inside the electrode, improve the density and flatness of the electrode, ensure the uniform distribution of current inside the electrode, and greatly enhance the continuity of the electrode. This is crucial for improving the capacitance density of MLCCs, reducing losses, and improving high-frequency characteristics.
[0033] 3. Advantages of microfluidic technology in nickel slurry dispersion: By forcing the slurry through a micron-level reaction chamber under ultra-high pressure, strong shearing force, cavitation effect and impact can be generated, which can completely break up the hard and soft agglomerates of nickel powder, reduce the particle size of the slurry, and make the slurry more uniformly dispersed, which is difficult to achieve with traditional stirring and ball milling. Attached Figure Description
[0034] Figure 1 The carbon nanotube slurry prepared in Example 1 is a solvent system dispersed in the slurry.
[0035] Figure 2 SEM image of the single-walled carbon nanotube composite conductive nickel paste prepared in Example 1.
[0036] Figure 3 The printing effect of the single-walled carbon nanotube composite conductive nickel paste prepared in Example 1. Detailed Implementation
[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or modifications made by those skilled in the art in terms of specific structural forms, process parameters, etc., without departing from the spirit and essence of the present invention, should all fall within the scope of protection of the present invention.
[0038] A method for preparing a single-walled carbon nanotube composite conductive nickel paste includes the following steps:
[0039] Step 1: Dissolve 0.4-1 part of PVB (polyvinyl butyral) with a molecular weight of 25,000-40,000 in 99-99.6 parts of terpineol, stir well to obtain solution A;
[0040] Step 2: Dissolve 0.2 to 1 part of single-walled carbon nanotubes in solution A, stir until homogeneous, and obtain solution B;
[0041] Step 3: Disperse solution B in a high-pressure homogenizer at a pressure of 80 MPa until D50 ≤ 4 μm to obtain a single-walled carbon nanotube conductive slurry in a solvent system.
[0042] Step 4: Add 20-50 parts of single-walled carbon nanotube conductive slurry in solvent system, 40-65 parts of organic solvent, 0.1-1 part of dispersant, 0.5-2 parts of resin, 0.1-1 part of thixotropic agent, and 0.1-1 part of coupling agent to a planetary stirrer and mix at 1000 rpm / min for 1 hour to obtain a pre-dispersion.
[0043] Step 5: Take 35-50 parts of pre-dispersion liquid, 9-13 parts of barium titanate powder, and 40-50 parts of nano nickel powder, and mix them in a degassing machine at 2000 rpm / min for 30 min;
[0044] Step 6: Grind the well-mixed slurry on a three-roll mill at 300 rpm / min until the fineness is less than 2 μm to obtain the ground slurry;
[0045] Step 7: Homogenize the ground slurry 3-5 times at a pressure of 20,000 psi on a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
[0046] In one possible embodiment, the organic solvent in step 4 is one or a combination of several of terpineol, butyl carbitol, solvent oil, diisononyl adipate, and 4-isopropyltoluene.
[0047] In one possible embodiment, the dispersant in step 4 is one or a combination of oleamide, fatty acid alkylammonium salt, and sorbitan monooleate.
[0048] In one possible embodiment, the resin in step 4 is one or a combination of ethyl cellulose, PVB, PVA, and epoxy resin.
[0049] In one possible embodiment, the thixotropic agent in step 4 is one or a combination of hydrogenated castor oil, fumed silica, and polycaprolactone.
[0050] In one possible embodiment, the coupling agent in step 4 is one or a combination of silane coupling agents and titanate coupling agents.
[0051] Example 1.
[0052] A method for preparing a single-walled carbon nanotube composite conductive nickel paste includes the following steps:
[0053] Step 1: Dissolve 0.8 parts of PVB in 99.2 parts of terpineol and stir until homogeneous to obtain solution A;
[0054] Step 2: Dissolve 0.8 parts of single-walled carbon nanotubes in solution A, stir until homogeneous, and obtain solution B;
[0055] Step 3: Disperse solution B under a high-pressure homogenizer at 80 MPa until D50 < 4 μm to obtain a single-walled carbon nanotube conductive slurry in a solvent system.
[0056] Step 4: Mix the single-walled carbon nanotube conductive slurry, terpineol, solvent oil, oleamide, ethyl cellulose, hydrogenated castor oil, and titanate coupling agent in a planetary stirrer at a speed of 1000 rpm / min for 1 hour to obtain a pre-dispersion.
[0057] Step 5: Take the pre-dispersed liquid, barium titanate powder, and nano nickel powder in proportions of 44 parts, 10 parts, and 46 parts respectively, and mix them in a degassing machine at 2000 rpm / min for 30 min.
[0058] Step 6: Grind the well-mixed slurry on a three-roll mill at 300 rpm / min until the fineness is less than 2 μm to obtain the ground slurry;
[0059] Step 7: Homogenize the ground slurry three times at 20,000 psi using a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
[0060] Depend on Figure 1 As can be seen, this invention abandons traditional water or NMP solvents and uses non-toxic and environmentally friendly terpineol to prepare a single-walled carbon nanotube conductive slurry with good dispersion and no agglomeration of carbon nanotubes, giving full play to its high aspect ratio advantage.
[0061] Depend on Figure 2 It can be seen that the overall slurry is well dispersed, with no agglomeration or defects; carbon nanotubes are well dispersed within it, forming an efficient transport network.
[0062] Depend on Figure 3 It can be seen that the single-walled carbon nanotube composite conductive nickel paste of Example 1 is in good condition after printing and sintering, with no phenomena such as paste seepage or cracking.
[0063] Example 2.
[0064] A method for preparing a single-walled carbon nanotube composite conductive nickel paste includes the following steps:
[0065] Step 1: Dissolve 0.4 parts of PVB in 99.6 parts of terpineol and stir until homogeneous to obtain solution A;
[0066] Step 2: Dissolve 0.8 parts of single-walled carbon nanotubes in solution A, stir until homogeneous, and obtain solution B;
[0067] Step 3: Disperse solution B under a high-pressure homogenizer at 80 MPa until D50 < 4 μm to obtain a single-walled carbon nanotube conductive slurry in a solvent system.
[0068] Step 4: Mix the single-walled carbon nanotube conductive slurry, terpineol, solvent oil, oleamide, ethyl cellulose, fumed silica, and titanate coupling agent in a planetary stirrer at a speed of 1000 rpm / min for 1 hour to obtain a pre-dispersion.
[0069] Step 5: Take the pre-dispersed liquid, barium titanate powder, and nano nickel powder and mix them in a degassing machine at 2000 rpm / min for 30 min, with the proportions of 44 parts, 13 parts, and 43 parts respectively.
[0070] Step 6: Grind the well-mixed slurry on a three-roll mill at 300 rpm / min until the fineness is less than 2 μm to obtain the ground slurry;
[0071] Step 7: Homogenize the ground slurry three times at 20,000 psi using a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
[0072] Example 3.
[0073] A method for preparing a single-walled carbon nanotube composite conductive nickel paste includes the following steps:
[0074] Step 1: Dissolve 0.4 parts of PVB in 99.6 parts of terpineol and stir until homogeneous to obtain solution A;
[0075] Step 2: Dissolve 0.4 parts of single-walled carbon nanotubes in solution A, stir until homogeneous, and obtain solution B;
[0076] Step 3: Disperse solution B under a high-pressure homogenizer at 80 MPa until D50 < 4 μm to obtain a single-walled carbon nanotube conductive slurry in a solvent system.
[0077] Step 4: Mix the single-walled carbon nanotube conductive slurry, terpineol, diisononyl adipate, oleamide, ethyl cellulose, hydrogenated castor oil, and titanate coupling agent in a planetary stirrer at a speed of 1000 rpm / min for 1 hour to obtain a pre-dispersion.
[0078] Step 5: Take the pre-dispersed liquid, barium titanate powder, and nano nickel powder and mix them in a degassing machine at 2000 rpm / min for 30 min, with the proportions of 44 parts, 13 parts, and 43 parts respectively.
[0079] Step 6: Grind the well-mixed slurry on a three-roll mill at 300 rpm / min until the fineness is less than 2 μm to obtain the ground slurry;
[0080] Step 7: Homogenize the ground slurry three times at 20,000 psi using a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
[0081] Table 1. Test results of the examples and comparative examples.
[0082]
[0083] As can be seen from Table 1, the test results of the products in each embodiment of the present invention are better than those of existing products on the market, and the product in Example 1 has the best effect. The single-walled carbon nanotube composite conductive nickel paste prepared by the present invention has high conductivity, excellent electrode continuity and good co-firing properties.
Claims
1. A method for preparing a single-walled carbon nanotube composite conductive nickel paste, characterized in that, Includes the following steps: Step 1: Dissolve PVB in terpineol and stir until homogeneous to obtain solution A; Step 2: Dissolve the single-walled carbon nanotubes in solution A and stir until homogeneous to obtain solution B; Step 3: Disperse solution B in a high-pressure homogenizer to obtain a single-walled carbon nanotube conductive slurry in a solvent system; Step 4: Mix the single-walled carbon nanotube conductive slurry, organic solvent, dispersant, resin, thixotropic agent, and coupling agent in the solvent system, and stir until uniform to obtain a pre-dispersion. Step 5: Take the pre-dispersed liquid, barium titanate powder, and nano nickel powder, and mix them in a degassing machine; Step 6: Grind the well-mixed slurry on a three-roll mill to obtain the ground slurry; Step 7: Homogenize the ground slurry multiple times on a microfluidic homogenizer to finally obtain single-walled carbon nanotube composite conductive nickel slurry.
2. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 1, the mass fraction of PVB is 0.4-1 part, the molecular weight of PVB is 25,000-40,000, and the mass fraction of terpineol is 99-99.6 parts.
3. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 2, the mass fraction of single-walled carbon nanotubes is 0.2 to 1 part.
4. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 3, the dispersion pressure is 80 MPa until D50 ≤ 4 μm.
5. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 4, the mass fraction of the single-walled carbon nanotube conductive slurry in the solvent system is 20-50 parts; the mass fraction of the organic solvent is 40-65 parts; and the mass fraction of the dispersant is 0.1-1 parts. The resin content is 0.5 to 2 parts by weight; The thixotropic agent is 0.1-1 parts by weight; the coupling agent is 0.1-1 parts by weight.
6. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 4, the organic solvent is one or a combination of several of the following: terpineol, butyl carbitol, solvent oil, diisononyl adipate, and 4-isopropyltoluene; the dispersant is one or a combination of several of the following: oleamide, fatty acid alkyl ammonium salt, and sorbitan monooleate.
7. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 4, the resin is one or a combination of ethyl cellulose, PVB, PVA, and epoxy resin; the thixotropic agent is one or a combination of hydrogenated castor oil, fumed silica, and polycaprolactone; and the coupling agent is one or a combination of silane coupling agents and titanate coupling agents.
8. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 5, the pre-dispersed liquid has a mass fraction of 35-50 parts, the barium titanate powder has a mass fraction of 9-13 parts, and the nano nickel powder has a mass fraction of 40-50 parts.
9. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, In step 6, the three-roll mill grinds the material at 300 rpm / min until the fineness is less than 2 μm.
10. The method for preparing single-walled carbon nanotube composite conductive nickel paste according to claim 1, characterized in that, The homogenization pressure is 20,000 psi, and the homogenization is performed 3-5 times.