A dry method for modifying silver powder, dry modified silver powder and application

Abstract

The application discloses a dry method for modifying silver powder, dry modified silver powder and application, and relates to the technical field of silver powder modification. The dry method for modifying silver powder comprises the following steps: S1, pre-dispersing silver powder; S2, after pre-dispersing is completed, sequentially adding organic acid solution, organic amine solution and high-molecular polymer solution under dispersion conditions; obtaining coated silver powder; S3, drying the coated silver powder to obtain dry modified silver powder with a characteristic surface coating layer; through dry mixing of silver powder, organic acid, organic amine and high-molecular polymer in the process of high-speed stirring or airflow crushing, uniform coating of the surface modifier of silver powder is realized. The organic acid, organic amine and high-molecular polymer can effectively reduce the surface energy of silver powder, enhance the dispersibility of silver powder in an organic medium, improve the fluidity and printing suitability of silver paste, and improve the compactness in the sintering process.

Description

Technical Field

[0001] This invention relates to the field of silver powder modification technology, and in particular to a dry modification method for silver powder, dry modified silver powder, and its applications. Background Technology

[0002] Photovoltaic silver paste, a core material for printed solar panels, has attracted significant attention due to its rheological and electrical properties. Silver powder, a key component for conductivity in silver paste, accounts for up to 90% of its mass and has a crucial impact on its rheological and electrical properties. With the rapid growth of the photovoltaic industry, the industry's demands for silver paste printing performance are becoming increasingly stringent. Improving the stability of silver powder in organic carriers and enhancing its wetting and dispersion properties in pastes have become research focuses.

[0003] To address these challenges, dry modification technology offers an environmentally friendly, easy-to-operate, and cost-effective solution. Through dry modification, silver powder can be surface-treated using specific modifiers under solvent-free or low-solvent conditions. This not only avoids the introduction of moisture and other impurities, ensuring the high purity and long-term stability of the silver powder, but also achieves uniform physical coating while maintaining high dispersion of the silver powder.

[0004] Therefore, optimizing the surface properties of silver powder using dry modification technology can not only significantly improve the interfacial bonding force between silver powder and organic carriers and enhance the wetting and dispersion performance of silver powder in slurry, but also simplify the production process and reduce energy consumption and production costs. Experimental results show that the rheological properties of silver powder after dry modification in slurry are significantly improved, providing a solid foundation for the preparation of high-performance photovoltaic silver paste and meeting the growing demand of the photovoltaic industry for high-quality silver paste.

[0005] Common silver powder modification methods include wet modification and dry modification. Wet modification involves using a large amount of organic solvent or water as a dispersion medium to disperse silver powder, followed by dissolving a modifier in the liquid phase for coating modification. Silver powder in the liquid phase often has a higher surface energy, making it prone to secondary agglomeration. Furthermore, materials modified by wet modification often require dehydration and drying, which can also lead to agglomeration and performance degradation. In contrast, dry modification disperses silver powder through mechanical force while simultaneously using a high-pressure airflow to spray an atomized modifier solution, achieving more uniform surface coating and eliminating the need for subsequent drying steps.

[0006] Patent application CN112853315A discloses a method for surface modification of silver powder in solar front-side silver paste. The method involves placing silver powder in a rotating chemical vapor deposition reaction chamber, using surface modifiers such as organic acids, organic amines, and inorganic iodine as reaction precursors, and high-purity Ar as the carrier gas and dilution gas. Under specific rotation speed, temperature, pressure, and time conditions, uniform coating modification of the silver powder surface is achieved. This invention, through rotating chemical vapor deposition technology, produces silver powder with a smooth surface and the characteristic of uniformly coating one or more functional groups, which can improve the printing resolution or electrical performance of the front-side silver paste.

[0007] However, the modification process of this patent requires continuous reaction in a heating chamber (0.1~1h) and relies on a vacuum system, resulting in high energy consumption. In addition, the selection of modifiers lacks the synergistic effect of "organic acid, organic amine, and polymer", which leads to upper limits on the dispersibility, sintering density and conductivity of silver powder. Summary of the Invention

[0008] This invention aims to provide a dry modification method for silver powder, dry-modified silver powder, and its applications. The method involves dry mixing silver powder with a specific surface modifier during high-speed stirring or air jet milling to achieve uniform coating of the silver powder with the surface modifier. The surface modifier is an organic acid, organic amine, or polymer, which can effectively reduce the surface energy of the silver powder, enhance its dispersibility in organic media, improve the fluidity and printability of the silver paste, and increase its density during sintering.

[0009] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: A dry modification method for silver powder includes the following steps: S1. The silver powder to be modified is pre-dispersed using a high-performance flow mixer; S2. After pre-dispersion, under dispersion conditions, organic acid solution, organic amine solution and polymer solution are sequentially added to a high-performance flow mixer to achieve layer-by-layer coating of the crushed and dispersed silver powder, thereby obtaining coated silver powder. S3. After drying the coated silver powder, dry-modified silver powder with a characteristic surface coating layer is obtained. The mass ratio of organic acid, organic amine, and polymer in the organic acid solution, organic amine solution, and polymer solution is 1~2:1~2:1~2; The total amount of organic acid, organic amine, and polymer added in the organic acid solution, organic amine solution, and polymer solution is 0.05~5.00 wt% of the silver powder mass.

[0010] In step S1, the silver powder to be modified is micron-sized spherical silver powder with a particle size distribution of 0.5~5.0μm; In step S1, the dispersion conditions for the silver powder are: the blade rotation frequency is 10~100Hz, the temperature is 25~80℃, and the blade rotation linear speed is 500~8000rpm.

[0011] In step S1, the dispersion time of the silver powder is 3-5 minutes. In step S2, the organic acid solution, organic amine solution, and polymer solution are sprayed into the silver powder chamber of a high-performance flow mixer through an atomizing nozzle under the action of a high-speed airflow; after spraying, the mixture continues to disperse for 3-5 minutes. The spraying time of the organic acid solution, organic amine solution, and polymer solution is less than 1 minute; In step S2, the mass concentration of the organic acid solution, organic amine solution, and polymer solution is 10% to 40%.

[0012] The organic acid solution, organic amine solution, and polymer solution are organic solvent solutions; The organic solvent includes any one or more of methanol, ethanol, n-propanol, isopropanol, butanol, ethylene glycol, propylene glycol, glycerol, terpineol, acetone, dimethyl butyl ether acetate, and diethylene glycol butyl ether acetate.

[0013] The organic acid includes at least one of sorbic acid, lauric acid, stearic acid, palmitic acid, oleic acid, and dodecyl stearic acid; The organic amines include any one or more of ethanolamine, propylenediamine, triethylamine, ethylenediamine, dimethylamine, isopropylamine, butylamine, cyclohexylamine, pyridine, morpholine, aniline, diethylamine, tetramethylethylenediamine, and hexamethylenetetramine.

[0014] The polymers include any one or more of the following: polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, ammonium polyacrylate, potassium polyacrylate, polyvinyl alcohol, polyethylene glycol, polyethyleneimine, polyquaternium salt, carboxymethyl cellulose, hydroxypropyl carboxymethyl cellulose, gum arabic, and gelatin.

[0015] The molecular weight of the polymer is 10³-10. 6 Da; In step S3, the drying method includes drying in a constant temperature forced-air drying oven at a drying temperature of 60~100℃.

[0016] A dry-modified silver powder, wherein the dry-modified silver powder is prepared by the above-mentioned dry modification method of silver powder.

[0017] An application of dry-modified silver powder, wherein the above-mentioned dry-modified silver powder is used to prepare photovoltaic silver paste, conductive paste or conductive coating.

[0018] The beneficial effects of this invention are: 1. This invention successfully improves the process flow for surface-modified silver powder by utilizing a high-speed airflow to incorporate organic acid solutions, organic amine solutions, and polymer solutions. This innovation not only greatly simplifies the silver powder surface coating process but also reduces the complexity and potential errors associated with multiple steps in traditional methods. Dry modification eliminates the need for additional solvent treatment and drying steps, thereby significantly improving production efficiency and reducing production costs.

[0019] 2. Compared with the untreated silver powder, the silver powder prepared by this invention can be better dispersed in an organic carrier while maintaining similar parameters such as particle size and specific surface area. This results in better printability of the paste and easier wire take-up. This ensures that the core conductivity of the silver powder is not affected, while simultaneously improving its application performance in pastes, especially in demanding applications such as solar panels.

[0020] 3. In this invention, shear thinning and sintering densification are achieved through the synergistic effect of organic acids, organic amines, and polymers. Organic acids adsorb onto the silver powder surface via carboxyl groups, forming a dense monolayer coating and reducing interparticle van der Waals forces. The amino groups in short-chain, low-boiling-point amines coordinate with the silver surface and simultaneously form hydrogen bonds with the carboxyl groups of the organic acids, creating a "carboxylic acid-amine" composite coating layer that enhances adsorption stability. The polymer is interspersed within the composite coating layer, weakly adsorbing onto the silver surface, providing steric hindrance, and regulating slurry viscosity. Furthermore, the dry process of progressively spraying organic acid, organic amine, and polymer solutions, by controlling the spraying order and the synergistic effect between the organic acids, organic amines, and polymers, solves the core problems of uneven coating, single function, and poor stability in traditional processes, while also endowing the silver powder with superior physicochemical properties and process adaptability. In addition, the stepwise spraying method of organic acids, organic amines, and polymers enables a functionally graded coating effect. The carboxylic acid monolayer plays a leading role, preferentially reducing van der Waals forces between particles. Subsequently, amine groups significantly enhance the binding energy through hydrogen bonding. Finally, the polymer intercalates within, providing steric hindrance for the entire structure. This unique layered structure can synergistically regulate interparticle forces, thereby achieving precise control over material properties. However, amide molecules, due to their fixed chain length, are difficult to achieve gradient adsorption, which may result in hydrophobic chains that are too long or too short, and lacks dynamic adjustment capability. In contrast, by adjusting the carbon chain length, branching degree, and molar ratio of organic acid / amine, the hydrophobicity, hydrogen bond density, and thermal decomposition characteristics of the coating layer can be flexibly controlled, making it adaptable to different slurry systems. Since the amide molecular structure is relatively fixed, functional adjustments often require the resynthesis of specific amide compounds, resulting in poor process flexibility.

[0021] 4. Compared with the traditional wet modification process, the dry modification method for silver powder developed in this invention does not require the use of large amounts of solvents and water, reducing production costs, lowering environmental treatment costs, and reducing the burden on the environment, thus achieving a greener and more sustainable production process. Compared with existing technologies, the dry modification method of this invention is simple to operate, low in cost, and environmentally friendly, and has broad prospects for industrial application. Attached Figure Description

[0022] Figure 1 This is a set of SEM images of silver particles in Embodiment 1 of the present invention.

[0023] Figure 2 This is a surface image of the sintered body under SEM in Group 1 of Embodiment 1 of the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0025] Example 1 This embodiment provides a dry-modified silver powder, which is prepared through the following steps: S1. The silver powder to be modified with a particle size distribution of 0.5~5.0μm is pre-dispersed in a high-performance flow mixer at a blade rotation frequency of 40Hz, a temperature of 50℃, and a blade rotation linear speed of 2500rpm for 5min. S2. After pre-dispersion, under dispersion conditions, organic acid solution, organic amine solution and polymer solution are sequentially added to a high-performance flow mixer to achieve layer-by-layer coating of the crushed and dispersed silver powder, thereby obtaining coated silver powder. Organic acid solutions, organic amine solutions, and polymer solutions are all ethanol solutions; The incorporation method involves placing the organic acid solution, organic amine solution, and polymer solution into separate material tanks. After sealing the material tanks, compressed air is used to spray the solutions into the silver powder chamber of a high-performance flow mixer through atomizing nozzles. The organic acid solution, organic amine solution, and polymer solution are sequentially sprayed into the silver powder chamber of the high-performance flow mixer. The spraying time is controlled within 1 minute, and dispersion continues for 3 minutes after spraying is completed, while the frequency, temperature, and blade rotation linear speed remain constant. S3. The coated silver powder is dried in a constant temperature forced-air drying oven at 75℃ to obtain dry-modified silver powder with a characteristic surface coating.

[0026] In this embodiment, the different types and amounts of amine raw materials are divided into 3 groups, and the types and amounts of raw materials in each group are shown in Table 1. Table 1. Types and amounts of raw materials used in groups 1-3 of Example 1

[0027] Example 2 This embodiment provides a dry-modified silver powder, which is prepared through the following steps: S1. The silver powder to be modified with a particle size distribution of 0.5~5.0μm is pre-dispersed in a high-performance flow mixer at a blade rotation frequency of 10Hz, a temperature of 25℃, and a blade rotation linear speed of 500rpm for 5min. S2. After pre-dispersion, under dispersion conditions, organic acid solution, organic amine solution and polymer solution are sequentially added to a high-performance flow mixer to achieve layer-by-layer coating of the crushed and dispersed silver powder, thereby obtaining coated silver powder. Organic acid solutions are ethanol solutions; organic amine solutions are acetone solutions; and polymer solutions are all propylene glycol solutions. The incorporation method involves placing the organic acid solution, organic amine solution, and polymer solution into separate material tanks. After sealing the material tanks, compressed air is used to spray the solutions into the silver powder chamber of a high-performance flow mixer through atomizing nozzles. The organic acid solution, organic amine solution, and polymer solution are sequentially sprayed into the silver powder chamber of the high-performance flow mixer. The spraying time is controlled within 1 minute, and dispersion continues for 4 minutes after spraying is completed, while the frequency, temperature, and blade rotation linear speed remain constant. S3. The coated silver powder is dried in a constant temperature forced-air drying oven at 60℃ to obtain dry-modified silver powder with a characteristic surface coating.

[0028] In this embodiment, the different types and amounts of amine raw materials are divided into 3 groups, and the types and amounts of raw materials in each group are shown in Table 2. Table 2. Types and amounts of raw materials used in groups 1-3 of Example 2

[0029] Example 3 This embodiment provides a dry-modified silver powder, which is prepared through the following steps: S1. The silver powder to be modified with a particle size distribution of 0.5~5.0μm is pre-dispersed in a high-performance flow mixer at a blade rotation frequency of 100Hz, a temperature of 80℃, and a blade rotation linear speed of 8000rpm for 4min. S2. After pre-dispersion, under dispersion conditions, organic acid solution, organic amine solution and polymer solution are sequentially added to a high-performance flow mixer to achieve layer-by-layer coating of the crushed and dispersed silver powder, thereby obtaining coated silver powder. Organic acid solutions are ethanol solutions; organic amine solutions are acetone solutions; and polymer solutions are all propylene glycol solutions. The incorporation method involves placing the organic acid solution, organic amine solution, and polymer solution into separate material tanks. After sealing the material tanks, compressed air is used to spray the solutions into the silver powder chamber of a high-performance flow mixer through atomizing nozzles. The organic acid solution, organic amine solution, and polymer solution are sequentially sprayed into the silver powder chamber of the high-performance flow mixer. The spraying time is controlled within 1 minute, and dispersion continues for 5 minutes after spraying is completed, while the frequency, temperature, and blade rotation linear speed remain constant. S3. The coated silver powder is dried in a constant temperature drying oven at 100℃ to obtain dry modified silver powder with a characteristic surface coating.

[0030] In this embodiment, the different types and amounts of amine raw materials are divided into 3 groups, and the types and amounts of raw materials in each group are shown in Table 3. Table 3. Types and amounts of raw materials used in groups 1-3 of Example 3

[0031] Comparative Example 1 The difference between this comparative example and Group 1 in Example 1 is that the mass ratio of organic acid, organic amine, and polymer in the organic acid solution, organic amine solution, and polymer solution is changed in this comparative example, while the other conditions are the same as in Example 1. In this comparative example, the different types and amounts of amine raw materials are divided into three groups, and the types and amounts of raw materials in each group are shown in Table 4. Table 4. Types and amounts of raw materials used in groups 1-3 of Comparative Examples 1

[0032] Comparative Example 2 The difference between this comparative example and Group 1 in Example 1 is that organic acid solution, organic amine solution or polymer solution is not used in this comparative example, while the other conditions are the same as in Example 1.

[0033] In this comparative example, the different types and amounts of amine raw materials were divided into 3 groups, and the types and amounts of raw materials in each group are shown in Table 5. Table 5. Types and amounts of raw materials used in groups 1-3 of Comparative Example 2

[0034] Comparative Example 3 The difference between this comparative example and Group 1 in Example 1 is that the organic acid solution, organic amine solution, or polymer solution is replaced with other raw materials, while the other conditions are the same as in Example 1.

[0035] In this comparative example, the different types and amounts of amine raw materials were divided into 3 groups, and the types and amounts of raw materials in each group are shown in Table 6. Table 6. Types and amounts of raw materials used in groups 1-3 of Comparative Examples 3

[0036] Application examples In this application example, photovoltaic silver paste was prepared from the dry-modified silver powder obtained in Examples 1-3 and Comparative Examples 1-3, respectively. The preparation formula consisted of 88% modified silver powder, 2.5% glass powder (containing TeO2-PbO system), and 9.5% organic carrier (terpineol + ethyl cellulose). After mixing, the mixture was dispersed multiple times using a three-roll mill and then degassed to ensure the uniformity of the silver paste texture.

[0037] Experimental Example In this experimental example, the performance of the dry-modified silver powder prepared in Examples 1-3 and Comparative Examples 1-3 and the photovoltaic silver paste prepared in the application example were tested respectively. The photovoltaic silver pastes in Examples 1 and 2 and Comparative Examples 1 to 3 were subjected to rheological tests (mainly viscosity, elastic modulus, and thixotropy) using a rheometer to predict their printability.

[0038] The photovoltaic silver paste from Examples 1 and 2 and Comparative Examples 1 to 3 was screen-printed onto the TCO conductive layer of the solar cell, then dried and cured at 700°C for 30 minutes, and the performance (specifically resistivity and ohmic contact) of the solar cell was tested.

[0039] The performance test results of the dry-modified silver powders prepared in Examples 1-3 and Comparative Examples 1-3 in this experiment are shown in Table 7. The performance test results of the photovoltaic silver paste prepared in this experimental example are shown in Table 8. Table 7. Performance test results of dry-modified silver powders prepared in Examples 1-3 and Comparative Examples 1-3

[0040] Table 8 Performance test results of photovoltaic silver paste prepared in application examples

[0041] like Figure 1 The image shown is a group of silver particle images under SEM in Example 1. Figure 2 The image shown is a surface view of the sintered body under SEM in Group 1 of Example 1.

[0042] As can be seen from the powder parameters in Table 7, the particle size distribution and specific gravity of the samples after dry modification are at the same level. Changing the specific organic acid, organic amine, polymer, and the amount added has no significant effect on the dispersion of the powder. The burn loss of Comparative Examples 1 and 2 differs from that of Example 1, mainly because the modification amount was adjusted in the modification scheme. The amount of each modifier in Comparative Example 1 was increased, resulting in a significantly higher burn loss, while the amount of each modifier in Comparative Example 2 was decreased, resulting in a significantly lower burn loss. This indicates that the modifier was successfully incorporated during the dry modification process, and the actual amount used can be further reflected by the burn loss.

[0043] As can be seen from the slurry parameters in Table 8, the synergistic stepwise coating strategy of organic acids, organic amines, and polymers significantly improves the slurry performance. In Examples 1-3, carboxylic acids preferentially adsorb onto the silver powder surface, effectively reducing van der Waals forces; organic amines enhance binding energy through hydrogen bonding; and polymers provide steric hindrance. The synergistic effect of these three components balances the slurry's viscosity, elastic modulus, and thixotropy, maintaining a resistivity of 3.05–3.15 μΩ·cm and an ohmic contact of 2.05–2.15 mΩ·cm. 2 All values ​​were at the optimal level. This gradient coating strategy effectively suppressed particle aggregation and ensured the integrity of the conductive network.

[0044] However, when the proportions of the organic acid, organic amine, and polymer in Comparative Example 1 are unbalanced, or when the modifier is absent in Comparative Example 2, the synergistic effect among the three modifiers is disrupted, leading to extreme variations in slurry properties. Excess organic acid results in excessively low viscosity and loose modulus; excessive organic amine or absence of polymer causes runaway viscosity and deterioration of thixotropy, respectively. The absence of any component increases resistivity to 3.88–4.02 μΩ·cm and ohmic contact to 2.85–3.05 mΩ·cm. 2 This indicates that agglomeration or uneven coating impairs conductivity. In Comparative Example 3, some common non-organic acids, non-organic amines, and non-polymers clearly failed to achieve the desired coating effect during modification, leading to uncontrolled slurry viscosity and thixotropy, and a significant increase in resistivity and ohmic contact.

[0045] In this invention, the carboxylic acid-amine-polymer gradient coating is achieved through precise three-step control: the organic acid monolayer inhibits aggregation, the organic amine strengthens the binding energy and stabilizes the structure, and the polymer intercalation provides dynamic response. This synergistic effect gives the slurry both fluidity and stability, while maintaining close contact between silver particles, ensuring low resistivity and ohmic contact. When a single component is excessive or absent, the gradient structure collapses. The absence of carboxylic acid leads to rigid aggregation, the absence of amine weakens the hydrogen bond network, and the absence of polymer causes viscosity to become uncontrolled.

[0046] This invention overcomes the shortcomings of traditional dry modification processes, such as insufficient performance and poor flexibility, by using step-by-step injection and ratio control, and achieves adjustable performance and optimized conductivity.

[0047] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A dry modification method for silver powder, characterized in that: Includes the following steps: S1. The silver powder to be modified is pre-dispersed using a high-performance flow mixer; S2. After pre-dispersion, under dispersion conditions, organic acid solution, organic amine solution and polymer solution are sequentially added to the high-performance flow mixer. The organic acid solution, organic amine solution and polymer solution are sprayed into the silver powder chamber of the high-performance flow mixer through an atomizing nozzle under the action of high-speed airflow. After spraying, dispersion continues for 3 min to 5 min to achieve layer-by-layer coating of the broken and dispersed silver powder, resulting in coated silver powder. S3. After drying the coated silver powder, dry-modified silver powder with a characteristic surface coating layer is obtained. The mass ratio of organic acid, organic amine, and polymer in the organic acid solution, organic amine solution, and polymer solution is 1~2:1~2:1~2; The total amount of organic acid, organic amine, and polymer added in the organic acid solution, organic amine solution, and polymer solution is 0.05 wt% to 5.00 wt% of the silver powder mass.

2. The dry modification method for silver powder according to claim 1, characterized in that: In step S1, the silver powder to be modified is micron-sized spherical silver powder with a particle size distribution of 0.5μm to 5.0μm.

3. The dry modification method for silver powder according to claim 1, characterized in that: In step S1, the dispersion conditions for the silver powder are: the blade rotation frequency is 10 Hz ~ 100 Hz, the temperature is 25℃ ~ 80℃, and the blade rotation linear speed is 500 rpm ~ 8000 rpm.

4. The dry modification method for silver powder according to claim 3, characterized in that: In step S1, the dispersion time of the silver powder is 3 min to 5 min.

5. The dry modification method for silver powder according to claim 1, characterized in that: The spraying time for the organic acid solution, organic amine solution, and polymer solution is less than 1 minute.

6. The dry modification method for silver powder according to claim 1, characterized in that: In step S2, the mass concentration of the organic acid solution, organic amine solution, and polymer solution is 10% to 40%.

7. The dry modification method for silver powder according to claim 1, characterized in that: The organic acid solution, organic amine solution, and polymer solution are organic solvent solutions.

8. The dry modification method for silver powder according to claim 7, characterized in that: The organic solvent includes any one or more of methanol, ethanol, n-propanol, isopropanol, butanol, ethylene glycol, propylene glycol, glycerol, terpineol, acetone, dimethyl butyl ether acetate, and diethylene glycol butyl ether acetate.

9. The dry modification method for silver powder according to claim 1, characterized in that: The organic acid includes at least one of sorbic acid, lauric acid, stearic acid, palmitic acid, oleic acid, and dodecyl stearic acid.

10. The dry modification method for silver powder according to claim 1, characterized in that: The organic amines include any one or more of ethanolamine, propylenediamine, triethylamine, ethylenediamine, dimethylamine, isopropylamine, butylamine, cyclohexylamine, pyridine, morpholine, aniline, diethylamine, tetramethylethylenediamine, and hexamethylenetetramine.

11. The dry modification method for silver powder according to claim 1, characterized in that: The polymers include any one or more of the following: polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, ammonium polyacrylate, potassium polyacrylate, polyvinyl alcohol, polyethylene glycol, polyethyleneimine, polyquaternium salt, carboxymethyl cellulose, hydroxypropyl carboxymethyl cellulose, gum arabic, and gelatin.

12. The dry modification method for silver powder according to claim 11, characterized in that: The molecular weight of the polymer is: 10³Da - 10 6 Da.

13. The dry modification method for silver powder according to claim 1, characterized in that: In step S3, the drying method is drying in a constant temperature forced-air drying oven at 60℃~100℃.

14. A dry-modified silver powder, characterized in that: The dry-modified silver powder is prepared by the dry modification method of the silver powder according to any one of claims 1-13.

15. An application of a dry-modified silver powder, characterized in that: The dry-modified silver powder according to claim 14 is used to prepare photovoltaic silver paste, conductive paste or conductive coating.

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