Method for recycling perovskite solar cells

Abstract

The application relates to a recycling method of a perovskite solar cell, comprising the following steps: dissolving the perovskite solar cell by using an aqueous solution of an aminocarboxylic multi-dentate complexing agent and a salt thereof at a first pH, so that lead ions are complexed with the aminocarboxylic multi-dentate complexing agent and the salt thereof to generate a water-soluble complex, and first solution is obtained through first solid-liquid separation; adjusting the pH of the first solution to a second pH, so that the aminocarboxylic multi-dentate complexing agent and the salt thereof are decomplexed with the lead ions, the lead ions react with halogen ions to generate a first lead halide precipitate. The recycling method of the perovskite solar cell is beneficial to simplifying the process and reducing energy consumption.

Description

Technical Field

[0001] This application relates to the field of battery recycling, and in particular to a method for recycling perovskite solar cells. Background Technology

[0002] Perovskite solar cells are a novel type of solar cell that utilizes organic-inorganic hybrid metal halides, such as organolead iodides, as the light-absorbing layer. They offer advantages such as low cost, high efficiency, and good stability, attracting increasing attention. In the recycling of perovskite solar cells, the perovskite light-absorbing layer is a key focus. From an environmental perspective, lead needs to be properly disposed of to avoid heavy metal pollution of water or soil; from an economic perspective, low-abundance iodine remains expensive. Therefore, the main purpose of perovskite solar cell recycling is to reduce the generation of toxic lead waste and recover the high-value iodine.

[0003] Traditional methods for recovering perovskite solar cells involve using solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP) to dissolve and extract the perovskite light-absorbing layer, followed by vacuum distillation to separate and recover lead iodide. However, vacuum distillation requires high temperatures and consumes a lot of energy. Summary of the Invention

[0004] Based on this, some embodiments of this application provide a method for recycling perovskite solar cells, which helps to simplify the process and reduce energy consumption.

[0005] A method for recycling perovskite solar cells includes the following steps:

[0006] At a first pH, the perovskite solar cell is dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt, so that lead ions can complex with the aminocarboxylic acid multidentate complexing agent and its salt to form a water-soluble complex. After a first solid-liquid separation process, a first solution is obtained.

[0007] The pH of the first solution is adjusted to a second pH, causing the aminocarboxylic acid multidentate complexing agent and its salt to decomplex with the lead ions. The lead ions then react with halide ions to form a first lead halide precipitate.

[0008] In some embodiments, the aminocarboxylic acid multidentate complexing agent includes one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and triethylenetetraaminehexaacetic acid.

[0009] In some embodiments, the first pH is 5-7, and the second pH is ≤1.

[0010] In some embodiments, in the step of adjusting the pH of the first solution to a second pH, hydrohalic acid is added to the first solution.

[0011] In some embodiments, the step of dissolving the perovskite solar cell at a first pH using an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt includes:

[0012] An alkaline reagent is added to an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt with a concentration of 0.1 mol / L to 1 mol / L to adjust the pH to the first pH. The alkaline reagent includes one or more of sodium hydroxide and potassium hydroxide.

[0013] The perovskite solar cell is dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt having the first pH.

[0014] In some embodiments, the step of generating the first lead halide precipitate is further followed by a second solid-liquid separation process to obtain a second solution;

[0015] The recovery method further includes: adding water-soluble lead salt to the second solution, so that the halide ions in the second solution react with the lead ions to generate a second lead halide precipitate.

[0016] In some embodiments, the water-soluble lead salt includes one or both of lead acetate and lead nitrate.

[0017] In some embodiments, the amount of water-soluble lead salt added is determined based on the mass of the first lead halide precipitate and the composition of the perovskite material in the perovskite solar cell.

[0018] In some embodiments, in the step of reacting the halide ions in the second solution with lead ions to generate a second lead halide precipitate, a third solid-liquid separation process is also performed to obtain a third solution. The recovery method further includes: adjusting the pH of the third solution to the first pH, and recovering the aqueous solution of the aminocarboxylic acid multidentate complexing agent and its salt.

[0019] In some embodiments, prior to the step of obtaining a first solution through a first solid-liquid separation process, the method further includes a step of recovering the transparent conductive glass.

[0020] The method for recovering perovskite solar cells according to some embodiments of this application includes: dissolving the perovskite solar cell in an aqueous solution of an aminocarboxylic acid-based multidentate complexing agent and its salt at a first pH. Taking FAPbI3 as an example, the FAPbI3 perovskite absorber layer material decomposes into PbI2 and FAI upon contact with water. At the first pH, lead ions in the perovskite absorber layer complex with the aminocarboxylic acid-based multidentate complexing agent and its salt to form a water-soluble complex, resulting in a first solution. The pH of the first solution is then adjusted to a second pH to weaken the complexing ability of the aminocarboxylic acid-based multidentate complexing agent and its salt, causing decomplexation with lead ions. The lead ions and iodide ions then redefine as lead iodide, thus achieving the recovery of lead iodide. It is understood that the above description only uses FAPbI3 as an example of perovskite absorber layer material. The A-site cation in the perovskite absorber layer material can also be other types, and the X-site halide ion is not limited to iodide ions but can also be other halide ions. The above-mentioned recovery method uses inexpensive aminocarboxylic acid multidentate complexing agents and their salt solutions. Under room temperature conditions, the valuable components of perovskite batteries can be efficiently recovered through simple pH adjustment and solid-liquid separation. The process is simple, does not require vacuum distillation or other methods, has low energy consumption, and meets the current requirements of energy conservation, emission reduction and circular economy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a process flow for recycling perovskite solar cells according to some embodiments of this application;

[0023] Figure 2 This is a schematic diagram of another process flow for recycling perovskite solar cells according to other embodiments of this application. Detailed Implementation

[0024] To facilitate understanding of this application, a more comprehensive description of the application will be provided below in conjunction with specific embodiments. Preferred embodiments of the application are given in the specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0027] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0028] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0029] In this application, "one or more" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0030] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0031] In this application, terms such as "further," "even more," "particularly," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later, but should not be construed as limiting the preceding technical solution or restricting the scope of protection herein. Unless otherwise specified herein, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0032] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0033] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0034] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0035] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0036] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0037] In the flowchart of this application, although the steps are shown sequentially according to the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps. They can be executed in other orders. Moreover, at least some of the steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. Their execution order is not necessarily sequential, but can be performed alternately or in turn with at least some of other steps or other sub-steps or stages.

[0038] Unless otherwise specified in this application, room temperature refers to a temperature of 10℃ to 30℃, and optionally, room temperature is 20℃ to 25℃.

[0039] Currently, degraded perovskite solar cell modules or defective products from the production process are the main targets for recycling perovskite solar cells, but there is still room for improvement in recycling methods. For example, some technologies involve sequentially dissolving and recovering the original solvents of each functional layer in the cell module. The perovskite layer is commonly extracted using original perovskite solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP), followed by antisolvent precipitation or vacuum distillation to separate and recover lead iodide. However, on the one hand, the solvents used for the perovskite layer typically have high boiling points of 157℃~205℃, making them more difficult to remove once solvates are formed. Even vacuum distillation requires high temperatures, resulting in high energy consumption. On the other hand, with the development of perovskite solar cell technology, current high-performance perovskite layers are no longer single-component MAPbI3 or FAPbI3. To improve efficiency and stability, various methods have been employed, including A-site cation doping (FA, MA, Cs, Rb, K, or one or more), X-site halide ion doping (Cl, Br, or one or more), and various molecular passivation techniques (phenylethyl ammonium iodide (PEAI), butyl ammonium bromide (BABr), and ferrocene (Fc), making the perovskite layer structure quite complex. Furthermore, some functional layer materials are readily soluble or dispersed in perovskite solvents, resulting in a mixed composition in the leachate. Simple distillation only yields a mixture of various materials in unknown proportions, which is difficult to reuse without further separation and purification.

[0040] Another related technology uses ion-exchange resins and strong oxidizing acids (such as nitric acid or perchloric acid) to treat perovskite waste. However, this method only recovers lead ions, discarding the more valuable iodide ions. Furthermore, the storage and use of strong oxidizing acids pose certain safety risks. Yet another related technology uses an aqueous solution containing sodium acetate, sodium iodide, and hypophosphorous acid to recover perovskite batteries, but this requires relatively high temperatures to achieve complete dissolution of the perovskite in the solution, resulting in high energy consumption.

[0041] Therefore, in actual recycling processes, especially for large-scale industrial processing, it is necessary to weigh the value of material recovery against energy consumption costs and provide a recycling method that simplifies the process and reduces energy consumption. In previous studies, this application used sodium thiosulfate solution to dissolve the perovskite layer, obtaining recovered transparent conductive glass and other functional layer materials. Subsequently, lead and iodine in the solution were precipitated and recovered. The entire process was carried out at room temperature in an aqueous phase, resulting in low energy consumption. However, the recovered lead hydroxide and cuprous iodide cannot be directly used in the fabrication of perovskite solar cells. Multiple reaction steps are required to prepare lead iodide, one of the main raw materials for perovskite, indicating room for improvement.

[0042] Based on this, this application further studies and provides a method for recycling perovskite solar cells that simplifies the process and reduces energy consumption. Please refer to [link to relevant documentation]. Figure 1 This includes the following steps S110 and S120:

[0043] Step S110: At the first pH, the perovskite solar cell is dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt, so that lead ions can complex with the aminocarboxylic acid multidentate complexing agent and its salt to form a water-soluble complex. After the first solid-liquid separation, the first solution is obtained.

[0044] Step S120: Adjust the pH of the first solution to the second pH, so that the aminocarboxylic acid multidentate complexing agent and its salt decomplex with lead ions, and lead ions react with halide ions to form the first lead halide precipitate.

[0045] The method for recovering perovskite solar cells in some embodiments of this application utilizes an aqueous solution of an aminocarboxylic acid-based multidentate complexing agent and its salt at a first pH to dissolve the perovskite solar cell. Taking FAPbI3 as an example, the FAPbI3 light-absorbing layer material of the perovskite solar cell decomposes into PbI2 and FAI. At the first pH, lead ions in the perovskite light-absorbing layer complex with the aminocarboxylic acid-based multidentate complexing agent and its salt ions to form a water-soluble complex, resulting in a first solution. The pH of the first solution is then adjusted to weaken the complexing ability of the aminocarboxylic acid-based multidentate complexing agent and its salt, causing decomplexation with lead ions. The lead ions and iodide ions then reprecipitate as lead iodide, thus achieving the recovery of lead iodide. It is understood that the above description only uses FAPbI3 as an example of perovskite light-absorbing layer material; the A-site cation in the above perovskite light-absorbing layer material can also be other cations, and the X-site halide ion is not limited to iodide ions but can also be other halide ions. The above-mentioned recovery method uses inexpensive aminocarboxylic acid multidentate complexing agents and their salt solutions. At room temperature, the valuable components of perovskite batteries can be efficiently recovered by simply adjusting the pH. The process is simple, does not require vacuum distillation or other methods, has low energy consumption, and meets the current requirements of energy conservation, emission reduction and circular economy.

[0046] Taking FAPbI3 as the perovskite light-absorbing layer material as an example, in this application, an aqueous solution of an aminocarboxylic acid-based multidentate complexing agent and its salt is used to dissolve the perovskite solar cell. The perovskite light-absorbing layer material FAPbI3 decomposes into PbI2 and FAI upon contact with water. A precipitation-dissolution equilibrium reaction of PbI2 and lead ions (Pb) are present in the solution. 2+ The lead ions undergo a coordination equilibrium reaction with aminocarboxylic acid multidentate complexing agents and their salt ions. At the first pH, lead ions are complexed with aminocarboxylic acid multidentate complexing agents and their salts to form water-soluble complexes, thereby dissolving the lead ions.

[0047] In addition, the above-mentioned recycling method uses aminocarboxylic acid-based multidentate complexing agents and their salts to dissolve the perovskite light-absorbing layer, causing the other functional layers in the perovskite solar cell to detach from the transparent conductive glass, thereby achieving the separate recycling of the transparent conductive glass and other functional layers, including the materials of each transport layer and the electrode layer.

[0048] Aminocarboxylic acid multidentate complexing agents and their salts refer to aminocarboxylic acid complexing agents and their salts having multiple coordinating atoms. In some embodiments, aminocarboxylic acid multidentate complexing agents include one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and triethylenetetraaminehexaacetic acid. The salts of aminocarboxylic acid multidentate complexing agents can be monosodium salts, disodium salts, tetrasodium salts, etc. The specific use of aminocarboxylic acid multidentate complexing agents or their salts is adjusted according to their state at a first pH. It is understood that only some commonly used aminocarboxylic acid multidentate complexing agents and their salts have been given above, but they are not limited to these. Aminocarboxylic acid multidentate complexing agents and their salts that can complex with lead ions at a first pH to form a water-soluble complex, dissolving the lead ions, and decomplex with lead ions at a second pH, causing the lead ions and halide ions to precipitate, forming lead halide precipitates, can all be used in this application.

[0049] In one example, aminocarboxylic acid multidentate complexing agents and their salts include ethylenediaminetetraacetic acid (EDTA). EDTA is more readily available and less expensive, which helps to further reduce recycling costs and facilitates industrial-scale recycling. For example, EDTA can be, but is not limited to, disodium EDTA (2Na).

[0050] In some embodiments, the first pH is 5-7, and the second pH is ≤1. At the first pH, the aminocarboxylic acid multidentate complexing agent and its salt can complex with lead ions to form a water-soluble complex, thereby dissolving the lead ions. At the second pH, the aminocarboxylic acid multidentate complexing agent and its salt can decomplex with lead ions, causing the lead ions to react with halide ions to obtain lead halide precipitate.

[0051] In some embodiments, the halide ions include one or more of iodide ions, bromide ions, and chloride ions.

[0052] The following uses ethylenediaminetetraacetic acid and its salt solution as an example to describe in detail the principle of the recovery method of some embodiments of this application. It can be understood that the principle of recovering perovskite solar cells by other aminocarboxylic acid multidentate complexing agents and their salt solutions is the same as that of ethylenediaminetetraacetic acid and its salt solution, and will not be repeated here.

[0053] Ethylenediaminetetraacetic acid (EDTA, commonly abbreviated as H4Y) is a polybasic acid that exhibits multiple dissociation equilibrations in aqueous solution. Its conjugate base is EDTA. 4- (Y) 4-PbI₂ ions can form extremely stable water-soluble chelates with metal ions in a 1:1 ratio. Although PbI₂ and I₂... - There is also a coordination equilibrium between them, but the fourth stability constant (lgβ4) of its complex is only 4.47. Therefore, the influence of this equilibrium reaction is ignored in this application.

[0054] When the perovskite light-absorbing layer comes into contact with ethylenediaminetetraacetic acid (EDTA) and its salt solutions, it rapidly decomposes into lead iodide (PbI2) and hydroiodates of A-site cations such as MAI and FAI. The precipitation-dissolution equilibrium reaction of PbI2 is the primary reaction in the solution. ; and lead ions (Pb 2+ ) and EDTA 4- Coordination equilibrium reaction: .

[0055] The two reactions above can be combined to obtain PbI2 and EDTA. 4- Precipitation-dissolution equilibrium reaction:

[0056] .

[0057] The equilibrium constant K of this reaction r It can be represented as:

[0058] .

[0059] in The solubility product of PbI₂ For [EDTAPb] 2- The stability constant, considering EDTA 4- With Pb 2+ The coordination of the acid is affected by the acid effect. The item needs to be corrected to:

[0060] = ;

[0061] in For EDTA 4- With Pb 2+ The apparent stability constant of coordination, Here is the acid effect coefficient of EDTA, and is the hydrogen ion concentration [H]. + The function of ], therefore PbI2 and EDTA 4- The equilibrium constant K of precipitation-dissolution equilibrium reaction r Ultimately, it can be expressed as:

[0062] ;

[0063] Taking the logarithm of both sides of the equation, we get:

[0064] .

[0065] In a 1.0 mol / L EDTA-2Na solution, calculations show that when pH=7, all Pb 2+ Both are in the format [EDTAPb] 2- It exists in the form of PbI₂, meaning the solubility of PbI₂ is 100%; when pH=5.1, 99.95% of PbI₂ is soluble. 2+ With [EDTAPb] 2- It exists in solution in its original form; when the solution pH=1, 99.85% of Pb is present. 2+ It will precipitate in the form of PbI2(s), with only 0.15% Pb. 2+ It remains in solution in ionic form, which is similar to the degree of ionization of PbI2 in pure water (0.12%).

[0066] Therefore, an EDTA salt solution with a pH of 5-7 is chosen to dissolve the perovskite layer. This not only completely dissolves PbI2 but also avoids corrosion of the perovskite transparent conductive glass by the strong acid solution. The pH is then adjusted to be less than or equal to 1 to ensure complete precipitation of PbI2 in the solution, thereby achieving the recovery of lead iodide.

[0067] In some embodiments, in the step of dissolving the perovskite solar cell with an aqueous solution of an aminocarboxylic acid-based multidentate complexing agent and its salt, the perovskite solar cell is immersed in the aqueous solution of the aminocarboxylic acid-based multidentate complexing agent and its salt. Optionally, ultrasonic treatment is performed simultaneously with immersion. Ultrasonic treatment allows for better dissolution of the layers in the perovskite solar cell and facilitates their detachment from the transparent conductive glass.

[0068] In one example, perovskite solar cells were immersed in an aminocarboxylic acid-based multidentate complexing agent and its salt solution until the functional layers detached and no yellow lead iodide precipitate was found on the surface of the transparent conductive glass.

[0069] In some embodiments, the step of dissolving the perovskite solar cell with an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt at a first pH includes:

[0070] Add an alkaline reagent to an aqueous solution of aminocarboxylic acid multidentate complexing agents and their salts with a concentration of 0.1 mol / L to 1 mol / L, and adjust the pH to the first pH.

[0071] The perovskite solar cell was dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt having a first pH.

[0072] In some embodiments, the alkaline reagent includes one or more of sodium hydroxide and potassium hydroxide. Further, the alkaline reagent may be added in the form of an aqueous solution to an aminocarboxylic acid multidentate complexing agent and its salt solution.

[0073] In some embodiments, prior to the step of obtaining the first solution through the first solid-liquid separation treatment, the method further includes a step of recovering the transparent conductive glass. Specifically, the transparent conductive glass is removed and ultrasonically cleaned sequentially with a surfactant, deionized water, acetone, and isopropanol, followed by ozone ultraviolet (UV-O3) treatment to remove residual components on the surface of the transparent conductive glass, thereby obtaining clean transparent conductive glass.

[0074] In some embodiments, the transparent conductive glass includes one or more of indium tin oxide (ITO) and fluorine-doped tin oxide (FTO). It should be understood that only two common types of transparent conductive glass are given above, but the invention is not limited to these.

[0075] More than half of the cost of perovskite solar cells is concentrated in the transparent conductive glass. Therefore, properly handling and recycling degraded perovskite solar cells or defective products from the production process to obtain reusable transparent conductive glass has significant economic value. Some embodiments of this application describe a method for recycling perovskite solar cells that uses an aminocarboxylic acid-based multidentate complexing agent with a first pH and its salt solution to dissolve the perovskite solar cell. This allows the functional layers to detach from the transparent conductive glass and avoids corrosion of the perovskite transparent conductive glass by strong acidic solutions, thereby recovering clean transparent conductive glass.

[0076] The first solution obtained after the first solid-liquid separation process contains water-soluble chelate ions and halide ions (such as I). - ), aminocarboxylic acid multidentate complexing agents and their salts containing metal cations such as sodium ions (Na+). + ), and cations at the A-site of perovskite such as methylamine ions (MA ions). + ), formamidinium ion (FA) + ), cesium ions (Cs) + One or more of the following: Depending on the structure of the recycled perovskite solar cell, the solid insoluble matter can be metal electrode materials, organic transport layer materials, or metal oxide materials, and can be selectively recycled based on their value. Among them, metal electrode materials include one or more of Au, Ag, and Cu, and organic transport layer materials include poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), C... 60 And one or more of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), etc., metal oxide materials including NiO xOne or more of SnO2 and ITO.

[0077] In some embodiments, the first solid-liquid separation process may be, but is not limited to, filtration.

[0078] In some embodiments, in the step of adjusting the pH of the first solution to a second pH, a hydrohalic acid is added to the first solution. For example, if the halide ion is an iodide ion, hydroiodic acid is added to the first solution. If the halide ion is a chloride ion, hydrochloric acid or the like is added to the first solution. In one example, the mass percentage concentration of hydroiodic acid may be, but is not limited to, 57%. The mass percentage concentration of hydrochloric acid may be, but is not limited to, 37%.

[0079] After adjusting the pH of the first solution to the second pH, lead ions undergo decomplexation with aminocarboxylic acid multidentate complexing agents and their salt ions, and react with halide ions to obtain lead halide precipitate. The lead halide precipitate is then washed and dried to obtain lead halide. The washing step uses one or both of water and isopropanol as the washing agent. In one example, the washing step includes water washing and isopropanol washing.

[0080] In some embodiments, the step of generating the first lead halide precipitate further includes a second solid-liquid separation process to obtain a second solution. The recovery method further includes adding a water-soluble lead salt to the second solution, causing the halide ions in the second solution to react with the lead ions to generate the second lead halide precipitate. The second lead halide precipitate is then washed and dried to obtain pure lead halide. In the washing step, the washing agent used includes one or both of water and isopropanol. In one example, the washing step includes water washing and isopropanol washing.

[0081] Taking FAPbI3 as the perovskite light-absorbing layer material as an example, after recovering PbI2, FAI still remains in the solution. Iodide ions have high recovery value, and by further recovering iodide ions from the second solution, the full recovery and utilization of iodide ions can be achieved. One related technology uses a high-concentration iodide solution (KI, NaI, NH4I, HI, etc.) to dissolve the perovskite, and then dilutes the solution to precipitate lead iodide. However, this method is only suitable for recovering lead iodide alone and cannot recover and utilize iodine elements in other iodine-containing components in the perovskite layer, such as MAI / FAI / CsI. In addition, in order to achieve the recycling of the recovered solution, these unused iodide ions will be oxidized and escaped during the subsequent distillation and concentration of the solution. The recycling methods in some embodiments of this application, on the one hand, utilize aminocarboxylic acid multidentate complexing agents and their salt solutions to dissolve perovskite layer materials, and achieve lead iodide recovery by adjusting pH changes, providing a method different from traditional technologies. On the other hand, some embodiments of this application also recover other iodine components in the perovskite layer, such as iodized salts containing A-site cations, achieving full recovery of iodine and reducing the waste of iodine.

[0082] In some embodiments, the water-soluble lead salt includes one or both of lead acetate and lead nitrate. In one example, lead acetate may be in the form of lead acetate trihydrate.

[0083] In some embodiments, the amount of water-soluble lead salt added is determined based on the mass of the first lead halide precipitate and the composition of the perovskite material in the perovskite solar cell.

[0084] Specifically, the molar amount of halide ions in the second solution is obtained based on the mass of the first lead halide precipitate and the composition of the perovskite material in the perovskite solar cell.

[0085] The molar amount of water-soluble lead salt is obtained from the molar amount of halide ions in the second solution.

[0086] In some embodiments, taking the perovskite material with the composition FAPbI3 as an example, the molar amount of iodide ions in the second solution is half the molar amount of the first lead iodide precipitate; the molar amount of water-soluble lead salt is 0.5 to 0.525 times the molar amount of iodide ions in the second solution.

[0087] In some embodiments, taking the perovskite material with a composition of FAPbI3 as an example, water-soluble lead salt is added to the second solution until no yellow precipitate forms. During the step of adding water-soluble lead salt to the second solution, lead ions react with iodide ions to form a yellow precipitate. If no yellow precipitate forms, it indicates that iodide ions in the solution have precipitated completely, and the addition of water-soluble lead salt can be stopped.

[0088] In some embodiments, the second solid-liquid separation process may be, but is not limited to, filtration.

[0089] In some embodiments, in the step of reacting halide ions in the second solution with lead ions to generate a second lead halide precipitate, a third solid-liquid separation process is further performed to obtain a third solution. The recovery method further includes: adjusting the pH of the third solution to a first pH, and recovering the aminocarboxylic acid multidentate complexing agent and its salt solution. The above method enables the recovery and reuse of aminocarboxylic acid multidentate complexing agents and their salt solutions.

[0090] In some embodiments, the third solid-liquid separation process may be, but is not limited to, filtration.

[0091] In some embodiments, please refer to Figure 2 The method for recycling perovskite solar cells includes the following steps: S210, S220, S230, S240, and S250.

[0092] Step S210: Obtain a first aminocarboxylic acid multidentate complexing agent with a pH of 5-7 and its salt solution. The aminocarboxylic acid multidentate complexing agent includes one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and triethylenetetraaminehexaacetic acid.

[0093] Step S220: Dissolve the perovskite solar cell with an aminocarboxylic acid multidentate complexing agent and its salt aqueous solution, so that lead ions can complex with the aminocarboxylic acid multidentate complexing agent and its salt to form a water-soluble complex. After the first solid-liquid separation, the first solution is obtained.

[0094] Step S230: Adjust the pH of the first solution to ≤1, so that lead ions can undergo decomplexation with aminocarboxylic acid multidentate complexing agents and their salts, and precipitate with halide ions. After a second solid-liquid separation process, the first lead halide precipitate and the second solution are obtained.

[0095] Step S240: Add water-soluble lead salt to the second solution to react the halide ions in the second solution with the lead ions until no precipitate is formed. After the third solid-liquid separation process, the second lead halide precipitate and the third solution are obtained.

[0096] Step S250: Adjust the pH of the third solution to the first pH, and recover the aminocarboxylic acid multidentate complexing agent and its salt solution.

[0097] The perovskite solar cell recovery method of the above embodiment utilizes an aqueous solution of an aminocarboxylic acid-based multidentate complexing agent and its salt at a pH of 5-7 to dissolve the perovskite solar cell. This causes lead ions in the perovskite light-absorbing layer to complex with the aminocarboxylic acid-based multidentate complexing agent and its salt ions, forming a water-soluble complex, thus obtaining a first solution. The pH of the first solution is then adjusted to weaken the complexing ability of the aminocarboxylic acid-based multidentate complexing agent and its salt, causing lead ions to decomplex with the aminocarboxylic acid-based multidentate complexing agent and its salt, and precipitate with halide ions to obtain a first lead halide precipitate and a second solution. A water-soluble lead salt is added to the second solution, causing the halide ions in the second solution to precipitate with lead ions, resulting in a second lead halide precipitate and a third solution. After pH adjustment, the third solution can be used to recover and reuse the aminocarboxylic acid-based multidentate complexing agent and its salt aqueous solution. The first and second lead halide precipitates achieve efficient recovery of halogen and lead elements from the perovskite layer. The above-mentioned recovery method uses inexpensive aminocarboxylic acid multidentate complexing agents and their salt solutions. Under room temperature conditions, the valuable components of perovskite batteries can be efficiently recovered through simple pH adjustment and solid-liquid separation. The process is simple, does not require vacuum distillation, has low energy consumption, and meets the current requirements of energy conservation, emission reduction and circular economy.

[0098] It is understood that in other embodiments, after obtaining the first lead halide precipitate and the second solution through the second solid-liquid treatment, the pH of the second solution can be directly adjusted to the first pH to recover the aminocarboxylic acid multidentate complexing agent and its salt solution for dissolving perovskite solar cells. After multiple recoveries of the aminocarboxylic acid multidentate complexing agent and its salt solution, the halide ion concentration accumulates to a certain level, and then water-soluble lead salt is added to it. After solid-liquid separation treatment, the second lead halide precipitate is obtained.

[0099] To make the objectives and advantages of this application clearer, the following detailed description of the perovskite solar cell recovery method and its effects, in conjunction with specific embodiments, is provided. It should be understood that the specific embodiments described herein are for illustrative purposes only and should not be construed as limiting the scope of this application. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the drugs and instruments used in the embodiments are conventionally selected in the art. Experimental methods in the embodiments that do not specify specific conditions were implemented under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0100] Example 1

[0101] This embodiment provides a method for recycling perovskite materials, including the following steps:

[0102] (1) Prepare an EDTA solution with a concentration of 1 mol / L. Adjust the pH of the EDTA solution to 7 with a 50% NaOH solution. Take 20 mL of the pH-adjusted solution and add it to a 100 mL conical flask. Add 5 g PbI2, 1 g FAI, 0.5 g MAI and 0.5 g CsI to the flask. Stir at room temperature for 3 h to 4 h until all the solids are dissolved to obtain the first solution.

[0103] (2) Under stirring, add 57% hydroiodic acid solution to the first solution until the pH of the first solution is 1. Filter the reaction mixture to obtain the first PbI2 precipitate and the second solution. The first PbI2 precipitate is washed several times with deionized water and isopropanol and then dried.

[0104] (3) Under stirring, lead acetate trihydrate was added to the second solution. The reaction mixture was filtered to obtain a second PbI2 precipitate and a third solution. The second PbI2 precipitate was washed several times with deionized water and isopropanol and dried. Based on the mass of the first and second PbI2 precipitates and the initial mass of PbI2, FAI, MAI, and CsI, the recovery rates of lead and iodine were calculated to be 99.5%. Recovery rate = mass of recovered element / initial mass × 100%.

[0105] (4) Add 50% NaOH solution to the third solution to readjust the pH of the solution to 7, and obtain the regenerated EDTA solution.

[0106] Furthermore, experiments have shown that both the first and second PbI2 precipitates recovered in the above embodiments are chemically pure.

[0107] Example 2

[0108] This embodiment provides a method for recycling perovskite solar cells, including the following steps:

[0109] (1) Prepare a 1 mol / L EDTA solution and adjust the pH of the EDTA solution to 7 with a 50% NaOH solution. Separate and fix several perovskite battery modules to be recycled on a cleaning rack. Place the cleaning rack properly in an ultrasonic cleaner, pour in a pH 7 EDTA solution to cover the battery modules, and use ultrasound to assist dissolution until all functional layers are detached and there is no yellow lead iodide residue on the substrate.

[0110] (2) Repeat the above steps until the EDTA solution can no longer dissolve the perovskite layer on the component. Remove the conductive substrate and clean it with surfactant, deionized water, acetone and isopropanol in sequence by ultrasonic cleaning. Then treat it with ozone and ultraviolet light for later use.

[0111] (3) After filtration, the first solution and insoluble matter are obtained. The solid insoluble matter remaining on the filter is washed, dried and stored in a nitrogen atmosphere.

[0112] (4) While stirring, add a 57% hydroiodic acid solution to the first solution until the pH of the first solution is 1. Filter the reaction mixture to obtain the first PbI2 precipitate and the second solution. The first PbI2 precipitate is washed several times with deionized water and isopropanol and then dried.

[0113] (5) Under stirring, lead acetate trihydrate was added to the second solution. The reaction mixture was filtered to obtain a second PbI2 precipitate and a third solution. The second PbI2 precipitate was washed several times with deionized water and isopropanol and dried. Based on the total mass of the first and second PbI2 precipitates and the initial mass of PbI2, FAI, MAI, and CsI, the recovery rates of lead and iodine were calculated to be 99.5%. Recovery rate = mass of recovered element / initial mass × 100%.

[0114] (6) Add 50% NaOH solution to the third solution to readjust the pH of the solution to 7, and obtain the regenerated EDTA solution.

[0115] Furthermore, experiments have shown that both the first and second PbI2 precipitates recovered in the above embodiments are chemically pure.

[0116] Example 1 directly uses EDTA solution to recover perovskite material, and the recovery rate obtained is close to that obtained from the perovskite solar cell in Example 2. It can be seen that the recovery method of perovskite solar cell in this application embodiment can efficiently recover iodine and lead in perovskite solar cell without interference from other layers in perovskite solar cell.

[0117] In Example 2 above, disodium ethylenediaminetetraacetate was used as an aminocarboxylic acid multidentate complexing agent and its salt. Experiments have shown that other aminocarboxylic acid multidentate complexing agents and their salts, such as diethylenetriaminepentaacetate, hydroxyethylethylenediaminetriacetate, and triethylenetetraaminehexaacetate, have the same effect as disodium ethylenediaminetetraacetate. The methods in the embodiments of this application can recover lead and halogens with high recovery rates, which will not be elaborated here.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for recycling perovskite solar cells, characterized in that, Includes the following steps: At a first pH, the perovskite solar cell is dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt, so that lead ions can complex with the aminocarboxylic acid multidentate complexing agent and its salt to form a water-soluble complex. After a first solid-liquid separation process, a first solution is obtained. The pH of the first solution is adjusted to a second pH, causing the aminocarboxylic acid multidentate complexing agent and its salt to decomplex with the lead ions. The lead ions then react with halide ions to form a first lead halide precipitate.

2. The method for recycling perovskite solar cells according to claim 1, characterized in that, The aminocarboxylic acid multidentate complexing agents include one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and triethylenetetraaminehexaacetic acid.

3. The method for recycling perovskite solar cells according to claim 1 or 2, characterized in that, The first pH is 5-7, and the second pH is ≤1.

4. The method for recycling perovskite solar cells according to claim 3, characterized in that, In the step of adjusting the pH of the first solution to the second pH, hydrohalic acid is added to the first solution.

5. The method for recycling perovskite solar cells according to claim 3, characterized in that, The steps for dissolving perovskite solar cells at a first pH using an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt include: An alkaline reagent is added to an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt with a concentration of 0.1 mol / L to 1 mol / L to adjust the pH to the first pH. The alkaline reagent includes one or more of sodium hydroxide and potassium hydroxide. The perovskite solar cell is dissolved in an aqueous solution of an aminocarboxylic acid multidentate complexing agent and its salt having the first pH.

6. The method for recycling perovskite solar cells according to any one of claims 1-2 and 4-5, characterized in that, In the step of generating the first lead halide precipitate, a second solid-liquid separation process is also performed to obtain a second solution; The recovery method further includes: adding water-soluble lead salt to the second solution, so that the halide ions in the second solution react with the lead ions to generate a second lead halide precipitate.

7. The method for recycling perovskite solar cells according to claim 6, characterized in that, The water-soluble lead salts include one or both of lead acetate and lead nitrate.

8. The method for recycling perovskite solar cells according to claim 6, characterized in that, The amount of water-soluble lead salt added is determined based on the mass of the first lead halide precipitate and the composition of the perovskite material in the perovskite solar cell.

9. The method for recycling perovskite solar cells according to claim 6, characterized in that, In the step of reacting the halide ions in the second solution with lead ions to generate the second lead halide precipitate, a third solid-liquid separation process is also performed to obtain a third solution. The recovery method further includes: adjusting the pH of the third solution to the first pH, and recovering the aqueous solution of the aminocarboxylic acid multidentate complexing agent and its salt.

10. The method for recycling perovskite solar cells according to claim 1, characterized in that, Before the step of obtaining the first solution through the first solid-liquid separation process, the process also includes the step of recycling the transparent conductive glass.

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