Method for preparing silicon-graphene interface-graphite negative electrode by utilizing photovoltaic waste

Abstract

The invention discloses a method for preparing a silicon-graphene interface-graphite negative electrode by utilizing photovoltaic waste, and relates to the technical field of preparation of photovoltaic waste and lithium ion battery energy storage materials, and the method comprises the following steps: mixing waste photovoltaic silicon crystals and caustic alkali in a ratio of (1-5): (2-10), and heating to a first temperature to remove a silicon nitride anti-reflection layer to obtain a waste mixture; washing and filtering the waste mixture with deionized water to obtain a pure silicon wafer; grinding the pure silicon wafer, and stirring and mixing the ground pure silicon wafer with the solid-liquid co-phase organic nano carbon source and graphite to obtain a mixed raw material; and calcining the mixed raw material in the inert atmosphere at a second high temperature for a second time to obtain the silicon-carbon negative electrode material. The problems that in the prior art, a photovoltaic silicon crystal waste treatment method is complex in process and high in cost are solved. Therefore, the preparation method of the silicon-carbon negative electrode material, which is simple to operate, low in cost, low in energy consumption and free of secondary pollution, is realized.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic waste and lithium-ion battery energy storage material preparation, and particularly relates to a method for preparing a silicon-graphene interface-graphite anode using photovoltaic waste. Background Art

[0002] In photovoltaic cell waste, the aluminum frame, glass cover plate, silver precious metal, and silicon crystal are the main products. Among them, the silicon crystal is tightly combined with silver wires and silicon nitride anti-reflection layers in the photovoltaic cell, and it is difficult to effectively separate the silicon crystal from other materials during the recycling process, resulting in difficult recycling of the silicon crystal, serious pollution, and low recycling value. In some waste recycling industries, it is often directly discarded into the environment, causing waste and environmental pollution.

[0003] As a raw material for the next-generation silicon-carbon anode material of lithium-ion batteries, silicon crystal has great potential and advantages. Compared with traditional graphite anode materials, silicon-carbon anode materials have higher specific capacity (the theoretical specific capacity of silicon is 4200 mAh / g, and the theoretical specific capacity of traditional graphite anode materials is 372 mAh / g), higher energy density (the silicon-carbon anode material combines silicon and carbon to give play to the advantages of both. Silicon provides an extremely high lithium-ion storage capacity, and carbon can buffer the stress caused by the volume expansion of silicon during charge and discharge), good cycle stability (the silicon-carbon anode material combines silicon and carbon, and the carbon material can effectively alleviate the side effect of silicon expansion, provide a good conductive network, and maintain structural stability), etc. Therefore, converting the silicon crystal in low-value photovoltaic cell waste into high-value silicon-carbon anode material is of great significance for promoting the development of the photovoltaic recycling industry.

[0004] However, in the process of preparing silicon-carbon anode material using photovoltaic waste, the processes of treating photovoltaic silicon crystal waste and preparing silicon-carbon composite anode are complex and costly. In the existing process, highly polluting and highly acidic reagents such as nitric acid, hydrochloric acid, and hydrofluoric acid are required to treat photovoltaic waste, and toxic and harmful waste gases, waste water, and waste residues will be generated during the reaction. If not properly treated, it will cause serious pollution to the soil, water source, and atmosphere. And these highly acidic reagents are corrosive, and a large amount of auxiliary materials such as neutralizing agents and cleaning agents are also required during the treatment process, resulting in high treatment costs. In addition, the existing preparation of silicon-carbon anode material requires the participation of nano-scale silicon materials, and the preparation process of nano-scale silicon materials is complex and usually requires precise processes and equipment, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), or laser ablation methods, and thus the preparation cost is also high. Summary of the Invention

[0005] By providing a method for preparing a silicon-graphene interface-graphite anode using photovoltaic waste in an embodiment of this application, the problems in the prior art that the treatment method of photovoltaic silicon crystal waste is complex and costly are solved.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing a silicon-graphene interface-graphite anode using photovoltaic waste, including: mixing waste photovoltaic silicon crystals and caustic alkali in a ratio of (1-5):(2-10), and heating to a first temperature to remove the silicon nitride antireflection layer to obtain a waste mixture; rinsing and filtering the waste mixture with deionized water to obtain a pure silicon wafer; grinding the pure silicon wafer, and stirring and mixing it with a solid-liquid co-phase organic nano carbon source and graphite to obtain a mixed raw material; calcining the mixed raw material in an inert atmosphere at a second high temperature for a second time to obtain a silicon-carbon anode material.

[0007] In combination with the first aspect, in a possible implementation, the first temperature is 180°C - 300°C.

[0008] In combination with the first aspect, in a possible implementation, the step of rinsing and filtering the waste mixture with deionized water to obtain a pure silicon wafer includes: cooling the waste mixture to room temperature, stirring and mixing it with deionized water until it becomes turbid to remove aluminum therein; sieving the turbid liquid to obtain broken silicon wafers; rinsing, centrifuging, precipitating, and vacuum drying the broken silicon wafers with deionized water multiple times to obtain the pure silicon wafer.

[0009] In combination with the first aspect, in a possible implementation, the step of grinding the pure silicon wafer, and stirring and mixing it with a solid-liquid co-phase organic nano carbon source and graphite to obtain a mixed raw material includes: mixing the pure silicon wafer and graphite, then ball milling with zirconia balls and sieving to obtain a graphite-silicon powder particle mixture; wherein, the mass ratio of the pure silicon wafer, graphite, and zirconia balls is (1-3):(4-27):(20-100); mixing the graphite-silicon powder particle mixture and the solid-liquid co-phase organic nano carbon source evenly in a mass ratio of (1-9):(1-2) to obtain the mixed raw material.

[0010] In combination with the first aspect, in a possible implementation, the step of grinding the pure silicon wafer, and stirring and mixing it with a solid-liquid co-phase organic nano carbon source and graphite to obtain a mixed raw material includes: ball milling the pure silicon wafer with zirconia balls and sieving to obtain silicon powder particles; wherein, the mass ratio of the pure silicon wafer to zirconia balls is 1:20; mixing the silicon powder particles, graphite particles, and the solid-liquid co-phase organic nano carbon source evenly in a ratio of (1-3):(2-9):(1-3) to obtain the mixed raw material.

[0011] In combination with the first aspect, in a possible implementation, after rinsing and filtering the waste mixture with deionized water, it further includes: centrifuging the turbid liquid after rinsing and filtering the waste mixture; vacuum drying the insoluble precipitate after centrifuging to obtain a silver mixture.

[0012] In combination with the first aspect, in a possible implementation manner, the method for preparing the solid-liquid co-phase organic nano carbon source includes: under the temperature condition of 25°C - 80°C, stirring and dissolving an acrylic resin monomer, medium-chain glycerol or medium-chain triglyceride, a photoinitiator, modified castor oil, and deionized water in a ratio of 1:1 to obtain a mixed emulsion; curing the mixed emulsion to obtain a nano-gel dispersion; performing high-pressure filtration on the nano-gel dispersion to remove the surfactant of the nano-gel dispersion; and drying the nano-gel dispersion after high-pressure filtration to obtain the solid-liquid co-phase organic nano carbon source.

[0013] In combination with the first aspect, in a possible implementation manner, the mesh number of the sieve for sieving the turbid liquid is 800 mesh - 1500 mesh.

[0014] In combination with the first aspect, in a possible implementation manner, the ball milling time using zirconia balls is 6h - 12h.

[0015] In combination with the first aspect, in a possible implementation manner, the second high temperature is 400°C - 1300°C; the second time is 1h - 4h.

[0016] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: In the embodiments of the present application, by mixing and heating waste photovoltaic silicon crystals with caustic alkali, the silicon nitride anti-reflection layer in the waste photovoltaic silicon crystals can be removed; by rinsing and filtering the waste mixture with deionized water, aluminum and the excess alkali on the surface can be removed; by mixing and heating silicon powder particles, graphite particles and the solid-liquid co-phase organic nano carbon source, a graphene interface between the graphite and the silicon powder particles can be generated. It effectively solves the problems of complex process and high cost in the existing treatment methods for waste photovoltaic silicon crystals. Furthermore, a preparation method for a silicon-carbon negative electrode material with simple operation, low cost, low energy consumption and no secondary pollution is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a flowchart of a method for preparing a silicon-graphene interface-graphite negative electrode using photovoltaic waste provided by the embodiments of the present application; Figure 2An example diagram of broken silicon wafers provided by an embodiment of the present application; Figure 3 An example diagram of pure silicon wafers provided by an embodiment of the present application; Figure 4 An example diagram of the mixed raw materials provided by an embodiment of the present application; Figure 5 A schematic diagram of the SEM morphology characterization of the silicon-carbon negative electrode provided by an embodiment of the present application; Figure 6 A schematic diagram of the EDS of the silicon-carbon negative electrode provided by an embodiment of the present application; Figure 7 A schematic diagram of the cycling performance of the silicon-carbon negative electrode half-cell prepared from the silicon-carbon negative electrode material provided by an embodiment of the present application. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0020] The following explains some technologies related to the embodiments of the present application to facilitate understanding. It should be considered that they are only exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described here without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, some descriptions of well-known functions and structures are omitted in the following description.

[0021] Figure 1 It is a flowchart of a method for preparing a silicon-graphene interface-graphite negative electrode using photovoltaic waste provided by an embodiment of the present application, including steps 101 to 104. Among them, Figure 1 It is only an execution order shown in the embodiment of the present application and does not represent the only execution order of a method for preparing a silicon-graphene interface-graphite negative electrode using photovoltaic waste. Under the condition that the final result can be achieved, Figure 1 The steps shown can be executed in parallel or reversed.

[0022] Step 101: Mix waste photovoltaic silicon crystals with caustic alkali in a ratio of (1 to 5):(2 to 10), and heat to a first temperature to remove the silicon nitride anti-reflection layer to obtain a waste mixture. In the embodiment of the present application, the first temperature is 180°C - 300°C. The caustic alkali is potassium hydroxide, sodium hydroxide, sodium carbonate or potassium carbonate.

[0023] Weigh the waste photovoltaic silicon crystals and caustic alkali in a ratio of 1:5, put them into a nickel crucible and stir to mix. Then, use a muffle furnace to heat the nickel crucible to the first temperature in an aerobic environment and keep it warm for 5 - 15 minutes, which can remove the silicon nitride anti-reflection layer of the waste photovoltaic silicon crystals and make the silver wires fall off, obtaining a waste mixture.

[0024] It should be noted that the waste photovoltaic silicon crystals in this application are for silicon chips containing silver with a size of 5 mm.

[0025] Step 102: Rinse and filter the waste mixture with deionized water to obtain pure silicon wafers. In the embodiment of this application, after cooling the waste mixture to room temperature, it is stirred and mixed with deionized water until it becomes turbid to remove the aluminum therein. The turbid liquid is sieved to obtain silicon chips. The silicon chips are rinsed, centrifuged, precipitated, and vacuum dried with deionized water multiple times to obtain pure silicon wafers. Among them, the mesh number of the sieve used for sieving the turbid liquid is 800 - 1500 meshes.

[0026] In addition, the turbid liquid after rinsing and filtering the waste mixture is centrifuged. The insoluble precipitate after centrifugation is vacuum dried to obtain a silver mixture.

[0027] Specifically, the waste mixture in the nickel crucible is cooled to room temperature, taken out and put into deionized water for stirring and mixing until it becomes turbid. The caustic alkali dissolves in water to remove the aluminum therein, and then the stirred turbid liquid is sieved with a sieve of 800 - 1500 meshes to separate the silicon chips from the solution. The silicon chips are as Figure 2 shown.

[0028] The silicon chips are repeatedly rinsed with deionized water, then the rinsing liquid is centrifuged, and the insoluble precipitate after centrifugation is vacuum dried to obtain pure silicon wafers. The pure silicon wafers are as Figure 3 shown.

[0029] In addition, those skilled in the art can also centrifuge the turbid liquid after rinsing and filtering the waste mixture, and vacuum dry the insoluble precipitate obtained after centrifugation to obtain a silver mixture, which can recover the silver precious metal therein.

[0030] Step 103: Grind the pure silicon wafers and stir and mix them with a solid-liquid co-phase organic nano-carbon source and graphite to obtain a mixed raw material. The mixed raw material is as Figure 4 shown.

[0031] In one embodiment of the present application, a pure silicon wafer is mixed with graphite and then ball-milled with zirconia balls and sieved to obtain a graphite-silicon powder particle mixture. Among them, the mass ratio of the pure silicon wafer, graphite, and zirconia balls is (1-3):(4-27):(20-100). The graphite-silicon powder particle mixture is uniformly mixed with a solid-liquid co-phase organic nano-carbon source at a mass ratio of (1-9):(1-2) to obtain a mixed raw material.

[0032] In another embodiment of the present application, a pure silicon wafer is ball-milled with zirconia balls and sieved to obtain silicon powder particles. Among them, the mass ratio of the pure silicon wafer to the zirconia balls is 1:20. The silicon powder particles, graphite particles, and solid-liquid co-phase organic nano-carbon source are uniformly mixed in a ratio of (1-3):(2-9):(1-3) to obtain a mixed raw material.

[0033] Specifically, the zirconia balls used here can be zirconia balls of different sizes. Exemplarily, 3 mm zirconia balls and 5 mm zirconia balls can be used in a ratio of 5:1. Or 3 mm zirconia balls, 5 mm zirconia balls, and 8 mm zirconia balls can be used respectively in a ratio of 5:2:1. The ball-milling time for ball-milling with zirconia balls is 6 h - 12 h. The graphite is flake graphite, conductive carbon black, or battery graphite.

[0034] In the embodiment of the present application, the preparation method of the solid-liquid co-phase organic nano-carbon source is as follows: Under the temperature condition of 25°C - 80°C, an acrylic resin monomer, medium-chain glycerol or medium-chain triglyceride, photoinitiator, modified castor oil, and deionized water are stirred and mutually dissolved in a ratio of 1:1 to obtain a mixed emulsion. The mixed emulsion is cured to obtain a nano-gel dispersion. The nano-gel dispersion is subjected to high-pressure filtration to remove the surfactant of the nano-gel dispersion. The nano-gel dispersion after high-pressure filtration is dried to obtain the solid-liquid co-phase organic nano-carbon source.

[0035] In the preparation process of the existing silicon-carbon anode material, nano-scale silicon materials need to be added. The preparation process of nano-scale silicon materials is complex and the preparation cost is relatively high. However, in this application, only the pure silicon wafer needs to be ball-milled to obtain micron-scale silicon powder particles, which can be used to prepare the silicon-carbon anode material. The preparation process is greatly simplified and the preparation cost is saved.

[0036] Step 104: The mixed raw material is calcined at a second high temperature for a second time in an inert atmosphere to obtain a silicon-carbon anode material. In the embodiment of the present application, the second high temperature is 400°C - 1300°C. The second time is 1 h - 4 h. The inert atmosphere can be a single gas such as nitrogen, argon, helium, etc., or a mixed gas of several inert gases.

[0037] Specifically, a graphene layer is in-situ chemically induced to form on the surface of the silicon powder particles by the solid-liquid co-phase organic nano-carbon source.

[0038] As Figure 5 shown in Figure 6 Figure 6, there are respectively a schematic SEM (scanning electron microscope, used to display the surface morphology and microstructure of the silicon-carbon anode) morphology characterization diagram of the silicon-carbon anode provided by the embodiment of the present application and a schematic EDS (scanning electron microscope, used to determine the types and contents of elements existing in the silicon-carbon anode) diagram of the silicon-carbon anode.

[0039] According to the above steps 101 to 104, the following embodiments are carried out to further illustrate the present application.

[0040] Embodiment 1 At room temperature, 5 g of waste photovoltaic silicon wafers are put into 3 g of solid-phase caustic alkali for mixing. The nickel crucible is heated to 280 °C by a muffle furnace and the mixture of the above waste photovoltaic silicon wafers and caustic alkali is put in. It is kept warm at 280 °C for 5 minutes to obtain a waste mixture. The waste mixture is taken out, cooled to room temperature, and 250 ml of deionized water is reserved. The waste mixture is poured into the deionized water and stirred with a stirring rod for 5 minutes to make it turbid. The turbid liquid is filtered out with an 800-mesh sieve to obtain the broken silicon wafers that sink to the bottom. The broken silicon wafers are repeatedly rinsed with deionized water, centrifuged, and precipitated, and then vacuum dried at 60 °C for 12 hours to obtain pure silicon wafers. The pure silicon wafers are put into zirconia balls and mixed and ball-milled for 12 hours, and the ratio of the sizes of the zirconia balls of 3 mm and 5 mm is 5:1. Then, after passing through an 800-mesh sieve, they are mixed evenly with graphite particles and a solid-liquid coexisting organic nano-carbon source in a ratio of 1:5:2, and calcined at 800 °C for 1 hour in an argon atmosphere to obtain a silicon-carbon anode material.

[0041] Embodiment 2 At room temperature, 250 g of mixed alkali is taken, and the ratio of potassium hydroxide to sodium hydroxide in the mixed alkali is 2:3. The mixed alkali is put into a nickel crucible and heated to 300 °C by a muffle furnace. 250 g of waste photovoltaic silicon wafers are taken and poured into the molten alkali, and heating is continued for 1 minute to obtain a waste mixture. The waste mixture is poured out and cooled to room temperature. 1 L of deionized water is reserved. The waste mixture is poured into the deionized water and stirred with a stirrer for 10 minutes, and the turbid liquid is filtered out to obtain the broken silicon wafers that sink to the bottom. The broken silicon wafers are repeatedly rinsed with deionized water, centrifuged, and precipitated, and then the insoluble precipitate is dried under high blast to obtain pure silicon wafers. The pure silicon wafers are mixed and ball-milled with 3-mm zirconia balls, 5-mm zirconia balls, and 8-mm zirconia balls in a ratio of 5:2:1 for 6 hours, and then passed through an 800-mesh sieve to obtain silicon powder particles. The silicon powder particles are mixed with flake graphite particles and a solid-liquid coexisting organic nano-carbon source in a ratio of 1:4:1, and calcined at 500 °C for 2 hours in a nitrogen atmosphere to obtain a silicon-carbon anode material.

[0042] Embodiment 3 At room temperature, using the silicon powder particles prepared in Example 2, 1 g of the solid-liquid co-phase organic nano carbon source and 0.25 g of the silicon powder particles were added to 1 g of graphite particles and stirred with a stirring rod. Finally, it was placed in a tube furnace and calcined at 600 °C for 2 h in an argon atmosphere to obtain the silicon-carbon anode material.

[0043] The silicon-graphene interface-graphite anode prepared from the silicon-carbon anode material of this application exhibits the characteristics of adjustable capacity and high cycle stability during the lithium-ion battery test.

[0044] This application uses a combined strategy of caustic alkali solid-phase hot melting and solid-liquid co-phase organic nano carbon source-induced silicon-graphene interface-graphite anode to directly convert waste photovoltaic silicon crystals into silicon-carbon anode materials for lithium-ion batteries. The method of this application can obtain a high-performance silicon-carbon anode material, which can be directly used in lithium-ion batteries. Compared with the methods of acid etching and organic solvent decomposition, it has low cost, the materials can be recycled, the application is simple and the energy consumption is less. This application uses crushed silicon wafers and reduces the size of the silicon wafers by means of ball milling, mechanical grinding, etc. to reach silicon powder particles close to the micron level, and prepares the precursor (i.e., the mixed raw materials) for the high-performance silicon-carbon anode material by mixing with graphite and the solid-liquid co-phase organic nano carbon source. The method of this application has low cost, uses green and easily available raw materials, has a simple preparation process, is easy to apply, the material is environmentally friendly and will not cause secondary pollution.

[0045] In this application, the interface of graphene between graphite and silicon is formed by in-situ chemical induction of a graphene layer on the surface of silicon particles by a solid-liquid co-phase organic nano carbon source. There is no participation of any CVD process in the preparation of the silicon-carbon anode material, the operation is simple and the cost is low. The synthesized silicon-graphene interface-graphite anode has the characteristics of adjustable capacity and adjustable price cost in lithium-ion batteries. The schematic diagram of the cycle performance of the silicon-carbon anode half-cell prepared from the silicon-carbon anode material is as Figure 7 shown. Among them, voltage represents voltage, with the unit V (volt), and Specific capacity (mAh g -1 ) represents the specific capacity, which represents the amount of electricity (milliampere-hour) that the battery material per unit mass (usually grams) can store.

[0046] Although this application provides the method operation steps as described in the examples or flowcharts, more or fewer operation steps may be included based on routine or non-creative labor. The order of steps listed in this embodiment is only one way among the execution orders of numerous steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in this embodiment or the drawings or in parallel (for example, in an environment of parallel processors or multi-threaded processing).

[0047] The various embodiments in this specification are described in a progressive manner. For the same or similar parts among the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0048] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for preparing a silicon-graphene interface-graphite negative electrode using photovoltaic waste, characterized in that: include: Mixing waste photovoltaic silicon crystals with caustic soda in a ratio of (1-5):(2-10), and heating to a first temperature to remove the silicon nitride anti-reflection layer to obtain a waste mixture; The waste mixture is rinsed and filtered with deionized water to obtain a pure silicon wafer; Grinding the pure silicon wafer, and stirring and mixing with a solid-liquid co-phase organic nano-carbon source and graphite to obtain a mixed raw material; The mixed raw material is calcined in an inert atmosphere at a second high temperature for a second time to obtain a silicon-carbon negative electrode material.

2. The method according to claim 1, characterized in that The first temperature is 180°C-300°C.

3. The method according to claim 1, characterized in that The waste mixture is rinsed and filtered with deionized water to obtain a pure silicon wafer, comprising: After cooling the waste mixture to room temperature, the mixture is stirred and mixed with deionized water until it becomes turbid, so as to remove aluminum therein; The turbid liquid is sieved to obtain broken silicon wafers; The broken silicon wafers are rinsed with deionized water for multiple times, centrifuged, precipitated and vacuum dried to obtain the pure silicon wafers.

4. The method according to claim 1, characterized in that: The pure silicon wafer is ground and mixed with a solid-liquid co-phase organic nano-carbon source and graphite to obtain a mixed raw material, including: The pure silicon wafer and graphite are mixed, ball-milled with zirconium oxide balls, and sieved to obtain a graphite silicon powder particle mixture; wherein the mass ratio of the pure silicon wafer, graphite and zirconium oxide balls is (1-3):(4-27):(20-100); The graphite silicon powder particle mixture and the solid-liquid co-phase organic nano-carbon source are uniformly mixed in a mass ratio of (1-9):(1-2) to obtain the mixed raw material.

5. The method according to claim 1, characterized in that The pure silicon wafer is ground and mixed with a solid-liquid co-phase organic nano-carbon source and graphite to obtain a mixed raw material, including: The pure silicon wafer is ball-milled with zirconium oxide balls and sieved to obtain silicon powder particles; wherein the mass ratio of the pure silicon wafer to the zirconium oxide balls is 1:20; The silicon powder particles, graphite particles and the solid-liquid co-phase organic nano-carbon source are uniformly mixed in a ratio of (1-3):(2-9):(1-3) to obtain the mixed raw material.

6. The method according to claim 1, characterized in that After the waste mixture is rinsed and filtered with deionized water, the method further comprises: Centrifuging the turbid liquid after washing and filtering the waste mixture; The insoluble precipitate after centrifugation is vacuum dried to obtain a silver mixture.

7. The method according to claim 1, characterized in that The preparation method of the solid-liquid co-phase organic nano-carbon source comprises: Under the temperature condition of 25° C.-80° C., acrylic resin monomer, medium-chain propylene glycol or medium-chain triglyceride, photoinitiator, modified castor oil and deionized water are stirred and dissolved in a ratio of 1:1 to obtain a mixed emulsion; solidifying the mixed emulsion to obtain a nanogel dispersion; High-pressure filtration is performed on the nanogel dispersion to remove the surfactant of the nanogel dispersion; The nanogel dispersion after high pressure filtration is dried to obtain a solid-liquid co-phase organic nanocarbon source.

8. The method according to claim 3, characterized in that The mesh number of the sieve used to sieve the turbid liquid is 800-1500 mesh.

9. The method according to claim 4 or 5, characterized in that: The ball milling time of the zirconia balls is 6h-12h.

10. The method according to claim 1, characterized in that The second high temperature is 400°C-1300°C; The second time is 1h-4h.

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