Preparation method of conductive silver powder composite material for photovoltaic silver paste

Abstract

The invention discloses a preparation method of a conductive silver powder composite material for photovoltaic silver paste, and relates to the technical field of photovoltaic raw material preparation.The preparation method comprises the steps that soluble copper salt is dissolved in water, excessive reducing metal powder is added for a mixed reaction, acid liquor is added into the solution after the mixed reaction is completed till no bubble is generated, and the conductive silver powder composite material is obtained; a first solution is obtained, and the first solution is filtered to obtain nanoscale copper powder; copper powder is added into the silver nitrate solution containing graphene oxide to obtain a second solution, the mass ratio of the copper powder to silver nitrate is (1-1000): 1, and the mass ratio of silver nitrate to graphene oxide is (5-10000): 1; adding a reducing agent solution into the second solution, carrying out a stirring reaction, and obtaining a mixture after the reaction is finished; and filtering and washing the mixture, and drying to obtain the silver powder composite material. The problem of high cost of the current precious metal for the photovoltaic silver paste can be solved by utilizing the raw materials and the process method with relatively low cost.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic raw material preparation, in particular to a method for preparing a conductive silver powder composite material for photovoltaic silver paste. Background Art

[0002] Photovoltaic cells are the core raw materials for photovoltaic power generation and play a core role in photoelectric conversion. Silver paste, which plays a role in the carrier conduction of silicon wafers, is one of the most important conductive materials in photovoltaic cells. The quality of silver paste directly affects the current collection efficiency, and its resistivity and ohmic contact quality are key factors in measuring the performance of photovoltaic cells.

[0003] However, silver metal is a relatively expensive precious metal with a relatively high cost. In order to solve this problem, a method for preparing a conductive silver powder composite material for photovoltaic silver paste is proposed. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a conductive silver powder composite material for photovoltaic silver paste to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a conductive silver powder composite material for photovoltaic silver paste, the preparation method comprising: Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder; Adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; The mixture is filtered, washed and dried to obtain a silver powder composite material.

[0006] As a further solution of the present invention: the soluble copper salt is one or more combinations of copper sulfate, copper chloride, copper nitrate, basic copper carbonate, basic copper sulfate, and copper ammine complex ion complex.

[0007] As a further embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 10-60 min, with a stirring speed of 2000-10000 r / min.

[0008] As a further embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 20-50 min, with a stirring speed of 4000-8000 r / min.

[0009] As a further embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 50°C for 35 min at a speed of 6000 r / min.

[0010] As a further embodiment of the present invention: the acid solution is one or more combinations of hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, phosphoric acid, hypochlorous acid, perchloric acid, formic acid, acetic acid, propionic acid, oxalic acid, maleic acid, and citric acid.

[0011] As a further solution of the present invention: copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (200-800):1, and the mass ratio of silver nitrate to graphene oxide is (2000-8000):1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0012] As a further solution of the present invention: copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 500:1, and the mass ratio of silver nitrate to graphene oxide is 5000:1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0013] As a further embodiment of the present invention: the reducing agent is one or more combinations of sodium borohydride, sodium triacetoxyborohydride, hydrazine hydrate, glucose, fructose, dithiothreitol, glyceraldehyde, glycerol, dimethylamine, ethanolamine, diethanolamine, triethanolamine, arachidonic acid, etc.

[0014] As a further embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 40-99°C for 30-300 min, with a stirring speed of 2000-10000 r / min.

[0015] Compared with the prior art, the invention has the following beneficial effects: dissolving a soluble copper salt in water, adding an excess of reducing metal powder for mixed reaction, adding acid to the solution after the mixed reaction is completed until no bubbles are generated to obtain a first solution, filtering the first solution to obtain nano-scale copper powder; adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000): 1, and the mass ratio of silver nitrate to graphene oxide is (5-10000): 1; adding a reducing agent solution to the second solution, stirring the reaction, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; filtering and washing the mixture, and drying it to obtain a silver powder composite material. The invention can solve the problem of high cost of precious metals used in current photovoltaic silver pastes by using relatively low-cost raw materials and process methods. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0017] An embodiment of the present invention provides a method for preparing a conductive silver powder composite material for photovoltaic silver paste, which comprises the following steps S1-S3.

[0018] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0019] In an embodiment of the present invention, the soluble copper salt may be one or more combinations of copper sulfate, copper chloride, copper nitrate, basic copper carbonate, basic copper sulfate, copper ammine complex, and the like.

[0020] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 10-60 min, with a stirring speed of 2000-10000 r / min.

[0021] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 20-50 min, with a stirring speed of 4000-8000 r / min.

[0022] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 50°C for 35 min at a speed of 6000 r / min.

[0023] In an embodiment of the present invention, the acid solution may be one or more combinations of hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, phosphoric acid, hypochlorous acid, perchloric acid, formic acid, acetic acid, propionic acid, oxalic acid, maleic acid, citric acid, etc.

[0024] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; add a reducing agent solution to the second solution, stir to react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0025] In an embodiment of the present invention, S2, adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000): 1, and the mass ratio of silver nitrate to graphene oxide is (5-10000): 1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material having a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (200-800):1, and the mass ratio of silver nitrate to graphene oxide is (2000-8000):1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0026] In an embodiment of the present invention, S2, adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000): 1, and the mass ratio of silver nitrate to graphene oxide is (5-10000): 1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material having a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 500:1, and the mass ratio of silver nitrate to graphene oxide is 5000:1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0027] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 40-99°C for 30-300 min, with a stirring speed of 2000-10000 r / min.

[0028] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 60-80°C for 70-260 min, with a stirring speed of 4000-8000 r / min.

[0029] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 70°C for 160 min at a stirring speed of 6000 r / min.

[0030] In an embodiment of the present invention, the reducing agent can be one or more combinations of sodium borohydride, sodium triacetoxyborohydride, hydrazine hydrate, glucose, fructose, dithiothreitol, glyceraldehyde, glycerol, dimethylamine, ethanolamine, diethanolamine, triethanolamine, arachidonic acid, etc.

[0031] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0032] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0033] The present invention can solve the problem of high cost of precious metals used in current photovoltaic silver paste by utilizing relatively low-cost raw materials and process methods.

[0034] Example 1 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0035] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0036] In an embodiment of the present invention, the soluble copper salt may be a copper ammine complex ion complex.

[0037] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 95°C for 60 min at a stirring speed of 10000 r / min.

[0038] In the embodiment of the present invention, the acid solution may be perchloric acid.

[0039] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 1000:1, and the mass ratio of silver nitrate to graphene oxide is 10000:1; add a reducing agent solution to the second solution, stir and react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0040] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 99°C for 300 min at a stirring speed of 10000 r / min.

[0041] In an embodiment of the present invention, the reducing agent may be glyceraldehyde.

[0042] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0043] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0044] Example 2 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0045] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0046] In the embodiment of the present invention, the soluble copper salt can be a combination of copper nitrate, basic copper carbonate, basic copper sulfate, and copper ammine complex ion complex.

[0047] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5°C for 10 min at a speed of 2000 r / min.

[0048] In the embodiment of the present invention, the acid solution may be a combination of hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, phosphoric acid, hypochlorous acid, and perchloric acid.

[0049] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 1:1, and the mass ratio of silver nitrate to graphene oxide is 5:1; add a reducing agent solution to the second solution, stir and react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0050] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 40°C for 30 min at a speed of 2000 r / min.

[0051] In the embodiment of the present invention, the reducing agent can be a combination of glucose, fructose, and dithiothreitol.

[0052] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0053] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0054] Example 3 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0055] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0056] In an embodiment of the present invention, the soluble copper salt may be copper sulfate.

[0057] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 95°C for 50 min at a stirring speed of 8000 r / min.

[0058] In the embodiment of the present invention, the acid solution may be phosphoric acid.

[0059] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 800:1, and the mass ratio of silver nitrate to graphene oxide is 8000:1; add a reducing agent solution to the second solution, stir and react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0060] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 80°C for 260 min, with a stirring speed of 8000 r / min.

[0061] In the embodiment of the present invention, the reducing agent may be hydrazine hydrate.

[0062] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0063] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0064] Example 4 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0065] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0066] In an embodiment of the present invention, the soluble copper salt may be basic copper carbonate.

[0067] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 5°C for 20 min at a speed of 4000 r / min.

[0068] In the embodiment of the present invention, the acid solution may be hydroiodic acid.

[0069] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 200:1, and the mass ratio of silver nitrate to graphene oxide is 2000:1; add a reducing agent solution to the second solution, stir and react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0070] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 60°C for 70 min at a speed of 4000 r / min.

[0071] In an embodiment of the present invention, the reducing agent may be arachidonic acid.

[0072] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0073] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0074] Example 5 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0075] S1. Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder.

[0076] In an embodiment of the present invention, the soluble copper salt may be copper nitrate.

[0077] In an embodiment of the present invention, the reaction conditions of the mixed reaction include: The reaction was stirred at 50°C for 35 min at a speed of 6000 r / min.

[0078] In the embodiment of the present invention, the acid solution may be hydrochloric acid.

[0079] S2. Add copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 500:1, and the mass ratio of silver nitrate to graphene oxide is 5000:1; add a reducing agent solution to the second solution, stir and react, and obtain a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

[0080] In an embodiment of the present invention, the reaction conditions of the stirring reaction include: The reaction was stirred at 70°C for 160 min at a stirring speed of 6000 r / min.

[0081] In an embodiment of the present invention, the reducing agent may be sodium borohydride.

[0082] S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material.

[0083] In the embodiment of the present invention, S3, filtering and washing the mixture, and then drying it to obtain a silver powder composite material, comprising: The drying method can be low temperature drying, freeze drying, spray drying and the like.

[0084] Example 6 A method for preparing a conductive silver powder composite material for photovoltaic silver paste comprises the following steps S1-S3.

[0085] S1. Weigh 200 g of soluble copper chloride and dissolve it in 1000 g of water, add 70 g of zinc metal powder, stir and react at 50° C. for 30 min, and stir at a speed of 2500 r / min. Add hydrochloric acid to the reaction solution until no bubbles are generated to obtain a first solution, and filter the first solution to obtain nano-scale copper powder.

[0086] S2. Weigh 50g of copper powder, add it to a silver nitrate solution containing graphene oxide, the mass of silver nitrate is 10g, the mass of graphene oxide is 0.2g, the mass of water is 200g, and 8g of reducing agent glucose is added. Stir the reaction at 70°C for 120min and the stirring speed is 3000r / min. After the reaction, a mixture of silver-coated copper nano- or micron-particle composite materials with a core-shell structure is obtained.

[0087] S3, filtering and washing the mixture, and then spray-drying the mixture to obtain a silver powder composite material.

[0088] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for preparing a conductive silver powder composite material for photovoltaic silver paste, characterized in that: The preparation method comprises: Dissolving a soluble copper salt in water, adding an excess amount of reducing metal powder for a mixing reaction, adding an acid solution to the solution after the mixing reaction is completed until no bubbles are generated to obtain a first solution, and filtering the first solution to obtain nano-scale copper powder; Adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; The mixture is filtered, washed and dried to obtain a silver powder composite material.

2. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: The soluble copper salt is one or more combinations of copper sulfate, copper chloride, copper nitrate, basic copper carbonate, basic copper sulfate, and copper ammine complex ion complex.

3. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: The reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 10-60 min, with a stirring speed of 2000-10000 r / min.

4. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 3, characterized in that: The reaction conditions of the mixed reaction include: The reaction was stirred at 5-95°C for 20-50 min, with a stirring speed of 4000-8000 r / min.

5. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 4, characterized in that: The reaction conditions of the mixed reaction include: The reaction was stirred at 50°C for 35 min at a speed of 6000 r / min.

6. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: The acid solution is one or more combinations of hydrochloric acid, sulfuric acid, nitric acid, hydroiodic acid, phosphoric acid, hypochlorous acid, perchloric acid, formic acid, acetic acid, propionic acid, oxalic acid, maleic acid, and citric acid.

7. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: Adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (200-800):1, and the mass ratio of silver nitrate to graphene oxide is (2000-8000):1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

8. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 7, characterized in that: Adding copper powder to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is (1-1000):1, and the mass ratio of silver nitrate to graphene oxide is (5-10000):1; adding a reducing agent solution to the second solution, stirring and reacting, and obtaining a mixture after the reaction is completed, wherein the mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure; including: Copper powder is added to a silver nitrate solution containing graphene oxide to obtain a second solution, wherein the mass ratio of copper powder to silver nitrate is 500:1, and the mass ratio of silver nitrate to graphene oxide is 5000:1; a reducing agent solution is added to the second solution, and the mixture is obtained after the reaction is completed. The mixture includes a silver-coated copper nano- or micron-particle composite material with a core-shell structure.

9. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: The reducing agent is one or more combinations of sodium borohydride, sodium triacetoxyborohydride, hydrazine hydrate, glucose, fructose, dithiothreitol, glyceraldehyde, glycerol, dimethylamine, ethanolamine, diethanolamine, triethanolamine, arachidonic acid, etc.

10. The method for preparing a conductive silver powder composite material for photovoltaic silver paste according to claim 1, characterized in that: The reaction conditions for the stirring reaction include: The reaction was stirred at 40-99°C for 30-300 min, with a stirring speed of 2000-10000 r / min.