Silver-coated silica aerogel powder, and preparation method and application thereof

Abstract

The application belongs to the technical field of conductive materials, and particularly relates to silver-coated silica aerogel powder and a preparation method and application thereof. The preparation method of the silver-coated silica aerogel powder comprises the following steps: S1, adding silica aerogel into a silver salt or silver complex solution; the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (1-9):1; S2, adding a reducing agent to form a silver coating layer on the surface of the silica aerogel to obtain silver-coated silica aerogel powder. The silver-coated silica aerogel provided in the application is a new type of conductive material, and the conductivity of the silver-coated silica aerogel can be close to the conductivity of pure silver. In a silver conductive paste, the silver-coated silica aerogel can replace silver powder, and the cost of the paste can be reduced without affecting the conductivity of the paste.

Description

Technical Field

[0001] This invention belongs to the field of conductive materials technology, specifically relating to a silver-coated silica aerogel powder, its preparation method, and its application. Background Technology

[0002] Aerogels typically refer to lightweight nanoscale solid materials composed of nanoporous networks formed by the aggregation of nanoscale ultrafine particles, with gaseous dispersion media filling the pores of the network. The most common type of aerogel is silica aerogel. Silica aerogel is an extremely lightweight, transparent material with high adsorption, high specific surface area, and high porosity, which makes it widely used in fields such as thermal engineering, acoustics, optical microelectronics, and particle detection.

[0003] Metal-supported silica aerogels are widely used in catalysts. For example, patent CN106391004A discloses a method for preparing a blocky silica aerogel-supported silver nanocatalyst and its application in the catalytic hydrogenation of 4-nitrophenol to 4-aminophenol. Loading silver onto a silica aerogel with a three-dimensional network structure increases the dispersion of silver and enhances its chemical stability, thereby increasing catalytic activity. Metal / silica aerogel composites are used in antibacterial and thermal insulation materials. For instance, patent CN116694158A discloses a water-based composite thermal insulation coating and its preparation method. Using Ag / SiO2 aerogel composites as fillers, it has noise reduction and sound insulation effects, significantly increasing the thermal insulation performance of the coating. Functional additives and coupling agents are coupled with the Ag / SiO2 aerogel composite to prevent agglomeration, improving the brittleness and poor toughness of silica aerogels and enhancing the durability of the coating.

[0004] The inventors have discovered that due to the poor conductivity of silica aerogels, neither the aforementioned silica aerogel-supported metal materials nor metal / silica aerogel composites have been used in the field of conductive materials. Therefore, this invention urgently needs to develop a novel material that allows silica aerogels to be used in conductive materials. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, this application provides a silver-coated silica aerogel powder, its preparation method and application, for use in conductive materials.

[0006] In a first aspect, this application provides a method for preparing silver-coated silica aerogel powder, which is achieved using the following technical solution: A method for preparing silver-coated silica aerogel powder, the method comprising the following steps: S1. Add silica aerogel to a silver salt or silver complex solution; the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (1-9):1. S2. Add a reducing agent to form a silver coating layer on the surface of the silica aerogel, and obtain silver-coated silica aerogel powder.

[0007] The silver-coated silica aerogel provided by this invention is a novel conductive material, which differs from silica aerogel loaded with metal materials and metal / silica aerogel composite materials. Silica aerogel can be used as a conductive material, and the conductivity of the silver-coated silica aerogel can approach that of pure silver. In silver conductive pastes, the silver-coated silica aerogel can replace silver powder, reducing the cost of the paste without affecting its conductivity.

[0008] Preferably, the specific surface area of ​​the silica aerogel is 200-300 m². 2 / g.

[0009] Preferably, the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (1-4):1.

[0010] More preferably, the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (2-4):1.

[0011] Preferably, the silica aerogel is a hydrophilic silica aerogel.

[0012] During the research process, this invention discovered that although the conductivity of silver-coated silica aerogel is close to that of pure silver, the conductive paste using silver-coated silica aerogel instead of silver powder has the following defects: First, the silver coating layer is prone to detachment during the conductive paste preparation process, which reduces the conductivity of the conductive paste; second, during the high-temperature sintering (850℃) process of the conductive paste, the silver layer coated by the silver-coated silica aerogel is prone to melt and separate from the silica aerogel, which reduces the conductivity of the conductive paste after sintering.

[0013] Preferably, the silica aerogel is a coupling agent modified silica aerogel.

[0014] Silver-coated coupling agent modified silica aerogel improves the stability of silver-coated silica aerogel. The silver coating of the silver-coated coupling agent modified silica aerogel is not easy to fall off during the preparation of conductive paste, thus improving the conductivity of conductive paste. Moreover, during the high-temperature sintering (850℃) of conductive paste, the silver coating of the silver-coated coupling agent modified silica aerogel is not easy to melt, and the silver layer will not separate from the silica aerogel, thus improving the conductivity of conductive paste after sintering.

[0015] Preferably, the preparation method of the coupling agent modified silica aerogel includes the following steps: Mix silica aerogel and deionized water, stir evenly, then add coupling agent and stir to obtain coupling agent modified silica aerogel; the mass ratio of silica aerogel, deionized water and coupling agent is 1:(100-1000):(0.001-0.05).

[0016] Preferably, the mass ratio of the silica aerogel, deionized water and coupling agent is 1:1000:(0.02-0.03).

[0017] Preferably, the coupling agent is a silane coupling agent.

[0018] Preferably, the silane coupling agent is selected from one or more of aminosilanes, epoxysilanes, methacryloxysilanes, mercapto / thiosilanes, vinylsilanes, ureosilanes, isocyanate-based silanes, and phenylsilanes.

[0019] Preferably, the aminosilane is selected from one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminopropylmethyldimethoxysilane, 3-diethylenetriaminopropyltrimethoxysilane, N-(2-dimethylaminoethyl)-3-aminopropylmethyldimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

[0020] More preferably, the aminosilane is 3-diethylenetriaminepropyltrimethoxysilane and / or N-phenyl-3-aminopropyltrimethoxysilane.

[0021] Preferably, the methacryloyloxysilane is selected from one or more of 3-acetoxypropyltrimethoxysilane, 3-methacryloyloxypropyltris(trimethylsiloxy)silane, 3-methacryloyloxypropyltriisopropoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane.

[0022] More preferably, the methacryloyloxysilane is 3-methacryloyloxypropyltriethoxysilane and / or 3-methacryloyloxypropyltrimethoxysilane.

[0023] Preferably, the phenylsilane is selected from one or more of phenyltrimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldimethoxysilane, and phenyltriethoxysilane.

[0024] More preferably, the phenylsilane is diphenyldiethoxysilane and / or diphenyldimethoxysilane.

[0025] Preferably, the reducing agent is selected from one or more of hydrazine hydrate, hydroxylamine sulfate, formaldehyde, dimethylborane, glucose, sucrose, fructose, tartaric acid, sulfinic acid, thiocarboxylic acid, or ascorbic acid.

[0026] Preferably, the preparation steps of the silver complex solution are as follows: Dissolve silver salt in deionized water, add a compound that can complex with silver, and stir until homogeneous to obtain a silver complex solution.

[0027] Preferably, the compound that can complex with silver is selected from one or more of ethylenediamine, ammonia, citrate, tartrate, ethylenediaminetetraacetate, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, polyethylenepolyamine, N,N'-dibenzylethylenediamine diacetate and its esters, and N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine.

[0028] More preferably, the complex is ethylenediaminetetraacetic acid salt.

[0029] In this invention, the ethylenediaminetetraacetic acid salt includes, but is not limited to, any one of ethylenediaminetetraacetic acid tetrasodium, ethylenediaminetetraacetic acid disodium, ethylenediaminetetraacetic acid tetrapotassium, or ethylenediaminetetraacetic acid dipotassium.

[0030] Preferably, the reducing agent is selected from one or more of hydrazine hydrate, hydroxylamine sulfate, formaldehyde, dimethylborane, glucose, sucrose, fructose, tartaric acid, sulfonic acid, sulfinic acid, thiocarboxylic acid, or ascorbic acid.

[0031] More preferably, the reducing agent is ascorbic acid.

[0032] Secondly, this application provides a silver-coated silica aerogel powder, which is achieved using the following technical solution: A silver-coated silica aerogel powder, wherein the silver-coated silica aerogel powder is prepared by the above-described preparation method.

[0033] Preferably, the silver content in the silver-coated silica aerogel powder is 50-90 wt%.

[0034] More preferably, the silver content in the silver-coated silica aerogel powder is 50-80 wt%.

[0035] More preferably, the silver content in the silver-coated silica aerogel powder is 67-80 wt%.

[0036] Thirdly, this application provides an application of silver-coated silica aerogel powder, achieved through the following technical solution: An application of silver-coated silica aerogel powder, wherein the silver-coated silica aerogel powder is used to produce conductive paste.

[0037] In summary, the present invention has the following beneficial effects: 1. The silver-coated silica aerogel provided by this invention is a novel conductive material, which is different from silica aerogel loaded with metal materials and metal / silica aerogel composite materials. Silica aerogel can be used as a conductive material, and the conductivity of silver-coated silica aerogel can be close to that of pure silver. In silver conductive paste, silver-coated silica aerogel can replace silver powder, which can reduce the cost of the paste without affecting its conductivity.

[0038] 2. The silver-coated coupling agent modified silica aerogel improves the stability of the silver-coated silica aerogel. The silver coating of the silver-coated coupling agent modified silica aerogel is not easy to fall off during the preparation of conductive paste, thus improving the conductivity of the conductive paste. Moreover, during the high-temperature sintering (850℃) of the conductive paste, the silver coating of the silver-coated coupling agent modified silica aerogel is not easy to melt, and the silver layer will not separate from the silica aerogel, thus improving the conductivity of the conductive paste after sintering. Attached Figure Description

[0039] Figure 1 This is a SEM image of the silver-coated silica aerogel powder prepared in Example 1 of the present invention. Detailed Implementation

[0040] The present application will be further described in detail below with reference to the embodiments.

[0041] Example

[0042] Example 1 provides a silver-coated silica aerogel powder, the preparation steps of which are as follows: S1. Dissolve 65g of silver nitrate in 12L of deionized water to obtain a silver salt solution. Add 78mL of ammonia water to the silver salt solution and stir for 5min. Then add 20g of hydrophilic silica aerogel and stir for 10min to obtain a mixed solution. S2. While stirring, add 500 mL of aqueous solution containing 110 g of glucose to the mixture obtained in step S1, stir for 20 min, filter, wash 4 times with deionized water, and dry at 100 °C for 6 h to obtain silver-coated silica aerogel powder.

[0043] Among them, the specific surface area of ​​the hydrophilic silica aerogel is 200 m². 2 / g.

[0044] Example 2 provides a silver-coated silica aerogel powder, which differs from Example 1 only in that the specific surface area of ​​the hydrophilic silica aerogel is 300 m². 2 / g.

[0045] Example 3 provides a silver-coated silica aerogel powder, which differs from Example 1 only in that the mass of the hydrophilic silica aerogel is 10g.

[0046] Comparative Example 1 provides a silica aerogel-supported silver powder, which differs from Example 1 only in that the mass of the hydrophilic silica aerogel is 200g.

[0047] Comparative Example 2 provides a silver / silica aerogel composite material, the preparation steps of which are as follows: S1. Dissolve 65g of silver nitrate in 12L of deionized water to obtain a silver salt solution. Add 78mL of ammonia water to the silver salt solution and stir for 5min. While stirring, add 500mL of aqueous solution containing 110g of glucose. S2. Under stirring conditions, 20g of silica aerogel and 0.4g of 3-aminopropyltriethoxysilane were added to the silver powder mixture obtained in step S1. The mixture was stirred for 10min, filtered, washed 4 times with deionized water, and dried at 100℃ for 12h to obtain the silver / silica aerogel composite material.

[0048] First, low-temperature conductive pastes were prepared using the silver-coated silica aerogel powder provided in Examples 1-3, the silica aerogel-loaded silver powder provided in Comparative Example 1, and the silver / silica aerogel composite material provided in Comparative Example 2.

[0049] 10g of silver-coated silica aerogel powder, the silica aerogel-supported silver powder provided in Comparative Example 1, and the silver / silica aerogel composite material provided in Comparative Example 2 were weighed out respectively. Then, 76g of silver powder, 6.5g of bisphenol A epoxy resin NPEL-128, 2.5g of triethylenetetramine and 4.0g of butylcarbamate were added and mixed evenly. The mixture was rolled into a fineness of less than 8μm using a three-roll mill to obtain low-temperature conductive pastes. The pastes were printed on an alumina substrate in a serpentine pattern, dried at 100℃ for 1h, and then cured at 200℃ for 20min. The resistance of the serpentine lines was measured after curing. The test data are shown in Table 1.

[0050] The bisphenol A epoxy resin NPEL-128 was purchased from Wanqing Chemical Technology Co., Ltd.

[0051] Table 1. Test results of Examples 1-3 and Comparative Examples 1-2 Resistance (mΩ / square) 6.5 7.6 7.0 Non-conductive Non-conductive

[0052] As can be seen from the test data of Examples 1-3 and Comparative Examples 1-2 in Table 1, the silver-coated silica aerogel provided by the present invention has good conductivity.

[0053] Example 4 provides a silver-coated silica aerogel powder, which differs from Example 1 only in that the silica aerogel is replaced by a coupling agent-modified silica aerogel at the same mass.

[0054] The preparation steps of coupling agent modified silica aerogel are as follows: Mix 20g of silica aerogel with 12L of deionized water, stir until homogeneous, then add 0.4g of 3-aminopropyltriethoxysilane, stir for 10min, filter, wash 4 times with deionized water, and dry at 100℃ for 12h to obtain coupling agent modified silica aerogel.

[0055] Example 5 provides a silver-coated silica aerogel powder, which differs from Example 4 only in that the mass of 3-aminopropyltriethoxysilane is 0.6g.

[0056] Example 6 provides a silver-coated silica aerogel powder, which differs from Example 4 only in that 3-aminopropyltriethoxysilane is replaced by 3-diethylenetriaminopropyltrimethoxysilane in equal mass.

[0057] Example 7 provides a silver-coated silica aerogel powder, which differs from Example 6 only in that 3-aminopropyltriethoxysilane is replaced by 3-methacryloyloxypropyltrimethoxysilane in equal mass.

[0058] Example 8 provides a silver-coated silica aerogel powder, which differs from Example 6 only in that 3-aminopropyltriethoxysilane is replaced by diphenyldimethoxysilane in equal mass.

[0059] Conductive slurries were prepared using the silver-coated silica aerogel powders provided in Examples 1 and 4-8, respectively. The specific procedures were as follows: Weigh out 10g of silver-coated silica aerogel powder, 76g of silver powder, 1.4g of ethyl cellulose, 12.6g of terpineol, 0.2g of copper oxide and 0.2g of BYK110 dispersant, mix the above raw materials evenly, and pass them through a three-roll mill to a fineness of less than 8μm to obtain a conductive paste.

[0060] The BYK110 dispersant was purchased from BYK in Germany.

[0061] The conductive paste was printed onto an alumina substrate in a serpentine pattern, dried at 100°C for 1 hour, and then sintered at 850°C for 10 minutes. The resistance of the serpentine lines was then measured. The test data are shown in Table 2.

[0062] Table 2 Test results of Examples 1 and 4-8 Resistance (mΩ / square) 12.0 3.0 2.8 3.4 3.6 3.2

[0063] As can be seen from the test data of Examples 4-8 and Example 1 in Table 2, the silver-coated coupling agent modified silica aerogel improves the stability of the silver-coated silica aerogel. The silver coating of the silver-coated coupling agent modified silica aerogel is not easy to fall off during the preparation of conductive paste, and the silver coating of the silver-coated coupling agent modified silica aerogel is not easy to melt during the high-temperature sintering process of conductive paste. The silver layer will not separate from the silica aerogel, thus improving the conductivity of the conductive paste after sintering at 850℃.

[0064] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing silver-coated silica aerogel powder, characterized in that, Includes the following steps: S1. Add silica aerogel to a silver salt or silver complex solution; the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (1-9):

1. S2. Add a reducing agent to form a silver coating layer on the surface of silica aerogel, and obtain silver-coated silica aerogel powder. The silica aerogel is a coupling agent modified silica aerogel; the preparation method of the coupling agent modified silica aerogel includes the following steps: mixing silica aerogel and deionized water, stirring evenly, then adding coupling agent, stirring, to obtain coupling agent modified silica aerogel; the mass ratio of silica aerogel, deionized water and coupling agent is 1:(100-1000):(0.001-0.05); The coupling agent is a silane coupling agent; the silane coupling agent is selected from one or more of aminosilane, methacryloxysilane, and phenylsilane.

2. The method for preparing silver-coated silica aerogel powder according to claim 1, characterized in that, The aminosilane is selected from one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminopropylmethyldimethoxysilane, 3-diethylenetriaminopropyltrimethoxysilane, N-(2-dimethylaminoethyl)-3-aminopropylmethyldimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

3. The method for preparing silver-coated silica aerogel powder according to claim 1, characterized in that, The methacryloyloxysilane is selected from one or more of 3-methacryloyloxypropyltris(trimethylsiloxy)silane, 3-methacryloyloxypropyltriisopropoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-methacryloyloxypropyltrimethoxysilane.

4. The method for preparing silver-coated silica aerogel powder according to claim 1, characterized in that, The phenylsilane is selected from one or more of phenyltrimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldimethoxysilane, and phenyltriethoxysilane.

5. The method for preparing silver-coated silica aerogel powder according to claim 1, characterized in that, The specific surface area of ​​the silica aerogel is 200-300 m². 2 / g; the mass ratio of silver to silica aerogel in the silver salt or silver complex solution is (1-4):

1.

6. A silver-coated silica aerogel powder, characterized in that, The silver-coated silica aerogel powder is prepared by the preparation method according to any one of claims 1-5; the silver content in the silver-coated silica aerogel powder is 50-90 wt%.

7. An application of the silver-coated silica aerogel powder as described in claim 6, characterized in that, The silver-coated silica aerogel powder is used to produce conductive paste.

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