A method for rapidly and greenly recovering lead ions in a perovskite solar cell by using iodine-based deep eutectic solvent

Abstract

The application discloses a method for rapidly and greenly recovering lead ions in a perovskite solar cell by using an iodine-based deep eutectic solvent, and belongs to the technical field of waste battery recycling and resource recycling. The method comprises the following steps: soaking a waste perovskite solar cell film in an iodine-based deep eutectic solvent, dissolving lead-containing components under the condition of heating and stirring, and obtaining a lead-rich supernatant through solid-liquid separation; adding an anti-solvent to the lead-rich supernatant, precipitating lead iodide, and obtaining a high-purity lead iodide crystal through washing and drying of the separated precipitate; and recovering the deep eutectic solvent and the anti-solvent through reduced pressure distillation of the separated solution and recycling the deep eutectic solvent and the anti-solvent. The method utilizes the strong coordination complexation and hydrogen bond synergistic effect of the iodine-based deep eutectic solvent on lead ions, realizes efficient leaching and high-purity recovery of lead, and is closed-loop operation, does not need to use volatile toxic organic solvents, and has the advantages of simple process, green environmental protection, high recovery efficiency, short processing period, recyclable solvent and the like.

Description

Technical Field

[0001] This invention belongs to the field of waste battery recycling and resource recycling technology, specifically involving a method and solvent recycling process for separating and recovering lead ions in perovskite solar cells using an iodine-based eutectic solvent. Background Technology

[0002] Lead halide perovskite solar cells (PSCs) possess excellent photovoltaic performance and good stability. They are also low-cost, simple to manufacture, and can be fabricated over large areas, making them a promising area for industrialization and a key area of ​​development in the photovoltaic field, with the potential to partially replace traditional silicon-based solar cells. However, the light-absorbing film inside PSCs contains a large amount of lead. When the cells age, the encapsulation is damaged, or they are scrapped, rainwater and moisture can penetrate the cell, causing hydrolysis of the perovskite. The organic iodide components in the crystals are highly soluble in water, and lead ions recombine with iodide ions to form lead iodide solid, which has extremely poor water solubility. Lead iodide can slowly dissolve in water and soil, releasing free lead ions. The migration characteristics of lead ions with the environment cause serious toxicity problems, posing a potential threat to the ecological environment and human health. This has become a core bottleneck restricting the large-scale application of PSCs. Therefore, it is urgent to develop new, green separation solvents and processes to achieve efficient separation of lead ions and high-purity recovery of lead iodide from perovskite solar cells.

[0003] Currently, methods for separating lead ions from perovskites mainly include solvent extraction leaching, electrolysis, and adsorption. Solvent extraction leaching encompasses two systems: one is the traditional highly toxic organic solvent system, and the other is a green and environmentally friendly solvent system primarily using eutectic solvents. The recovery process of this invention belongs to the second type of eutectic green solvent leaching system.

[0004] While recycling perovskite solar cells using eutectic solvents is environmentally friendly, achieving both high recovery rates and short processing times presents a significant challenge. For example, ZL202010352669.2 discloses a method for extracting lead iodide using a polyethylene glycol-based eutectic solvent, opening a new avenue for green lead iodide recycling. However, the eutectic solvent used in this process has poor lead iodide dissolution capabilities. At room temperature (25°C), continuous stirring for 24 hours is required to achieve saturated dissolution; even at 90°C, stirring for 2 hours is still needed to reach dissolution equilibrium. Shortening the stirring time significantly reduces the amount of lead iodide leached, drastically diminishing the recycling effect. Furthermore, the eutectic solvent used in this process cannot be recycled and is consumed only once. These multiple factors combined hinder the industrial-scale application of this technology.

[0005] To improve recovery rates and achieve solvent recovery, application number 202511014252.4 discloses a lead treatment and recovery process for lead-based perovskite solar cells based on antisolvent and resin treatment. This process relies on polar organic solvents to enhance lead iodide leaching and introduces an iodine source into the antisolvent to promote lead iodide precipitation; under these dual effects, the lead recovery rate can reach over 90%. However, the use of organic solvents throughout the process is detrimental to environmental sustainability. The introduced iodide ions recombine with lead ions to form solid lead iodide, making it difficult to separate and regenerate the iodine source, thus increasing recovery costs. Furthermore, the lead iodide leaching rate is relatively low; even after stirring at room temperature for 2 hours, some undissolved lead iodide remains, resulting in a long processing cycle.

[0006] Therefore, how to balance recycling rate, recycling time, recycling cost and environmental friendliness is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] To simultaneously achieve high recovery rate, short processing cycle, solvent recyclability, and environmental friendliness, this invention provides a method for the rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent, characterized by comprising the following steps:

[0010] S1: The waste perovskite solar cell film is immersed in an iodine-based eutectic solvent containing hydroxyl functional groups, heated and stirred to leach out, and the solid residue is removed by solid-liquid separation to obtain a lead-containing supernatant.

[0011] S2: Add antisolvent to the lead-containing supernatant to precipitate lead iodide precipitate. After solid-liquid separation, lead iodide precipitate and secondary supernatant are obtained.

[0012] S3: The lead iodide precipitate is washed and dried sequentially with anhydrous ethanol and ultrapure water to obtain high-purity lead iodide crystals;

[0013] S4: The secondary supernatant is separated by vacuum distillation to recover and regenerate the eutectic solvent and the antisolvent, which are then recycled for use in the leaching and precipitation processes.

[0014] Furthermore, during the leaching process in step S1, if the liquid lead ions in the iodine-based eutectic solvent leaching system are not saturated, waste perovskite solar cell films are continuously added for repeated leaching. After obtaining a saturated or high-concentration lead-containing solution, solid-liquid separation is then performed to obtain a lead-containing supernatant.

[0015] Furthermore, in step S1, the hydroxyl functional groups in the iodine-based eutectic solvent are provided by the alcohol component.

[0016] Furthermore, the iodine source of the iodine-based eutectic solvent includes, but is not limited to, metal iodides and 1-ethyl-3-methylimidazolium iodide.

[0017] Furthermore, in step S1, the iodine-based eutectic solvent is selected from any one of the following three systems: a eutectic solvent prepared by sodium iodide and ethylene glycol in a molar ratio of 1:3, a eutectic solvent prepared by potassium iodide and ethylene glycol in a molar ratio of 1:6, and a eutectic solvent prepared by 1-ethyl-3-methylimidazolium iodide and ethylene glycol in a molar ratio of 1:1.

[0018] Further, in step S1, the separated waste perovskite solar cell film is immersed in an iodine-based eutectic solvent and heated and stirred at 30–80°C for 30 min to leach out.

[0019] Furthermore, in step S2, the antisolvent is ultrapure water or anhydrous ethanol. Sufficient antisolvent is added to the lead-containing supernatant until lead iodide precipitate no longer precipitates.

[0020] Furthermore, in step S2, the volume ratio of the lead-containing supernatant to the antisolvent is 1:5.

[0021] Furthermore, in step S4, the solvent recovery is achieved by vacuum distillation using low-pressure rotary evaporation.

[0022] The extraction mechanism of this invention is as follows: Lead ions in waste perovskite solar cells can undergo strong coordination complexation with iodide ions in an iodine-based eutectic solvent; simultaneously, ethylene glycol stabilizes iodide ions through a hydrogen bonding network, solubilizes cations in the eutectic solvent, and provides a large amount of free I-. ⁻ Decoordination of Pb 2+ This maintains the liquid environment of the eutectic solvent and the solubility state of the lead-iodine complex. Through the synergistic effect of both coordinate and hydrogen bond networks, the stability of the resulting complex is significantly enhanced, thereby greatly improving the solvent's extraction efficiency and selectivity for lead ions, achieving highly efficient separation.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. Extremely high leaching efficiency: Under mild conditions of 25℃ and within 30 minutes of reaction, only 2 mL of NaI-based eutectic solvent system is required to achieve a PbI₂ solubility of up to 3.972 × 10⁻⁶. 5 mg / L.

[0025] 2. Fast leaching rate and simple operation: The leaching equilibrium time is short, requiring only conventional mixing and filtration operations, without the need for complex processes such as high-temperature calcination, making it extremely easy to achieve industrial-scale production.

[0026] 3. High-purity product recovery: Only the addition of a conventional antisolvent is needed to induce the precipitation of high-purity lead iodide crystals, and high-quality precursor materials can be obtained after simple vacuum filtration and washing.

[0027] 4. Solvent closed-loop recycling, green economy: Low-pressure rotary evaporation is used to achieve efficient separation and regeneration of eutectic solvent and antisolvent. The iodine component contained in the eutectic solvent itself is recovered and reused sustainably. The whole process operates in a closed loop, without using volatile and highly toxic traditional organic solvents, which greatly reduces the treatment cost and eliminates secondary pollution from the source. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a process flow diagram of the present invention.

[0030] Figure 2 The X-ray diffraction (XRD) patterns of the high-purity lead iodide crystals obtained in Examples 1-2 of this invention are shown.

[0031] Figure 3 The bar chart shows the lead iodide recovery rate after multiple recycling of the eutectic solvent in Examples 1-2 of this invention.

[0032] Figure 4 The solubility of lead ions in different eutectic solvent systems at different concentrations of lead iodide in Examples 3-5 of this invention.

[0033] Figure 5 The solubility of lead ions in the eutectic solvent at different temperatures in Examples 6-8 of this invention.

[0034] Figure 6 RDF curves of a eutectic solvent system with sodium iodide and ethylene glycol in a molar ratio of 1:3 and lead iodide.

[0035] Figure 7 UV-Vis absorption spectrum of lead iodide after leaching with a eutectic solvent. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] Example 1: In this example, a eutectic solvent with a sodium iodide-ethylene glycol molar ratio of 1:3 was selected.

[0038] See Figure 1 The process flow of this invention is as follows:

[0039] S1: Lead leaching from perovskite powder layer

[0040] The aged and powdered film on the surface of a waste perovskite solar cell substrate was peeled off to obtain a powder layer mainly composed of lead halide perovskite powder. This powder layer is used as the raw material for leaching and recovering lead ions using an iodine-based eutectic solvent in this invention. The powder layer was directly immersed and dissolved in 10 ml of a sodium iodide:ethylene glycol (1:3) eutectic solvent solution, and stirred at 60°C for 30 min until its concentration reached 1.798 × 10⁻⁶. 5 At a concentration of mg / L, during stirring, the lead halide perovskite in the powder layer decomposes upon contact with the solvent, releasing lead iodide. A large number of free iodide ions in the solvent system can coordinate with lead iodide to form a tetraiodide lead complex ion that can stably exist in the liquid phase: PbI₂ + 2 I⁻ - ⇌ [PbI4] 2- Meanwhile, the hydroxyl groups carried by the ethylene glycol component can form hydrogen bonds with iodide ions, further enhancing the dissolution effect of lead iodide and allowing the lead component to be fully transferred into the solvent. After leaching, a solid-liquid separation operation is carried out to filter out insoluble oxides, organic transport materials and other solid residues, finally obtaining a lead-containing supernatant containing lead complex ions.

[0041] S2: Lead iodide precipitates out.

[0042] Add 50 mL of ultrapure water as an antisolvent to the lead-containing supernatant obtained in step S1. The concentration of iodide ions in the supernatant decreases significantly, forcing the tetraiodide lead complex ion to dissociate. Lead ions recombine with iodide ions, precipitating as a solid lead iodide precipitate. Solid-liquid separation is achieved by filtration, and the lead iodide precipitate and secondary supernatant are collected separately. The obtained lead iodide precipitate is washed, dried, and then subjected to X-ray diffraction analysis. The corresponding XRD pattern of the product is shown below. Figure 2 As shown.

[0043] S3: Obtaining high-purity lead iodide crystals

[0044] Lead iodide precipitate was successively washed with anhydrous ethanol and ultrapure water, and then dried to obtain high-purity lead iodide crystals; according to Figure 2 The XRD pattern shown also confirms this.

[0045] S4: Solvent regeneration and recycling

[0046] The secondary supernatant is separated by vacuum distillation to separate the iodine-based eutectic solvent and the antisolvent, and then reused in the next leaching.

[0047] The recovered sodium iodide-ethylene glycol eutectic solvent and antisolvent were used to repeat steps S1-S4 of the above experiment for a complete cycle, running continuously for 5 times. The lead iodide recovery rate was recorded for each experiment, and the experimental results are as follows: Figure 3 As shown, the PbI2 recovery rates for the five cycles were 96.26%, 94.33%, 93.21%, 93.09%, and 92.17%, respectively, demonstrating extremely high solvent stability and recovery efficiency.

[0048] Example 2: In this example, a eutectic solvent solution of potassium iodide and ethylene glycol (1:6) was used.

[0049] The operating conditions for each step in Example 2 are completely consistent with those in Example 1, with the only differences being: firstly, in step S1, a potassium iodide-ethylene glycol eutectic solvent with a molar ratio of 1:6 is used for leaching; secondly, in step S1, the lead ion concentration at the leaching endpoint is controlled to be 1.35 × 10⁻⁶. 4 mg / L, and the remaining process parameters and operating steps are the same as in Example 1.

[0050] Statistical analysis of the results of five consecutive ring tests on the system in Example 2 showed that the PbI2 recoveries were 81.67%, 79.28%, 73.91%, 52.47%, and 43.30%, respectively (see...). Figure 3 ).

[0051] Comparing the recovery rates of Examples 1 and 2, it can be seen that the recovery rate of Example 2 is significantly lower than that of Example 1. This is related to the selection of the iodine-based eutectic solvent and the controlled leaching endpoint lead ion concentration.

[0052] To visually demonstrate the impact of different eutectic solvent systems and leaching temperatures on lead ion leaching, six additional examples are provided below for experimental illustration. Among them;

[0053] Examples 3-5: Using pure lead iodide powder, with a fixed leaching temperature and multiple gradients of lead iodide dosage, the lead dissolution capacity of three types of iodine-based eutectic solvents was tested.

[0054] Examples 6-8: Using pure lead iodide powder, multiple gradient leaching temperatures were set, and the saturated dissolution concentrations of excess lead iodide in three types of iodine-based eutectic solvents at different temperatures were measured. The theoretical saturated concentrations of each solvent were then obtained.

[0055] Example 3: In this example, a eutectic solvent with a sodium iodide-ethylene glycol molar ratio of 1:3 was selected.

[0056] 100 mg, 200 mg, 300 mg, and 400 mg of lead iodide were dissolved in 2 mL of a sodium iodide:ethylene glycol (1:3) eutectic solvent solution, respectively. The solutions were stirred at 60 °C for 30 min to obtain lead-containing eutectic solvent solutions. After filtration, 100 μL of the supernatant was collected, nitrated, and diluted with 2% nitric acid. The lead ion concentration was then measured using a flame atomic absorption spectrometer. Figure 4 As shown, its concentration is 4.8315 × 10⁻⁶. 4 mg / L, 8.095×10 4 mg / L, 1.628×10 5 mg / L, 2.017×10 5 mg / L.

[0057] Example 4: In this example, a eutectic solvent with a potassium iodide-ethylene glycol molar ratio of 1:6 was selected.

[0058] 100 mg, 200 mg, 300 mg, and 400 mg of lead iodide were dissolved in 2 mL of a potassium iodide:ethylene glycol (1:6) eutectic solvent solution, respectively. The solutions were stirred at 60 °C for 30 min to obtain lead-containing eutectic solvent solutions. After filtration, 100 μL of the supernatant was collected, nitrated, and diluted with 2% nitric acid. The lead ion concentration was then measured using a flame atomic absorption spectrometer. Figure 4 As shown, its concentration is 1.4375 × 10⁻⁶. 4 mg / L, 1.393×10 4 mg / L, 2.798×10 4 mg / L, 3.26×10 4 mg / L.

[0059] Example 5: In this example, an equimolar ratio of 1-ethyl-3-methylimidazolium iodide-ethylene glycol eutectic solvent was selected.

[0060] 100 mg, 200 mg, 300 mg, and 400 mg of lead iodide were dissolved in 2 mL of a 1:1 eutectic solvent solution of 1-ethyl-3-methylimidazolium iodide and ethylene glycol, respectively. The solutions were stirred at 60 °C for 30 min to obtain lead-containing eutectic solvent solutions. After filtration, 100 μL of the supernatant was collected, nitrated, and diluted with 2% nitric acid. The lead ion concentration was then measured using a flame atomic absorption spectrometer. Figure 4 As shown, its concentration is 4.66 × 10⁻⁶. 4 mg / L, 4.846×10 4 mg / L, 4.882×10 4 mg / L, 7.214×10 4 mg / L.

[0061] Example 6: In this example, a eutectic solvent with a sodium iodide-ethylene glycol molar ratio of 1:3 was selected.

[0062] Excess lead iodide was dissolved in 2 mL of a sodium iodide:ethylene glycol (1:3) eutectic solvent solution. The solution was stirred for 30 min at constant temperatures of 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, and 80℃ to obtain a lead-containing eutectic solvent solution. After filtration, 100 μL of the supernatant was taken, nitrated, and diluted with 2% nitric acid. The lead ion concentration was measured using a flame atomic absorption spectrometer. Figure 5 As shown, the measured lead ion concentrations were 3.972 × 10⁻⁶. 5 mg / L, 4.049×10 5 mg / L, 4.578×10 5 mg / L, 5.76×10 5 mg / L, 5.898×10 5 mg / L, 6.396×10 5 mg / L, 5.68×10 5 mg / L.

[0063] Example 7: In this example, a eutectic solvent with a potassium iodide-ethylene glycol molar ratio of 1:6 was selected.

[0064] Excess lead iodide was dissolved in 2 mL of a potassium iodide:ethylene glycol (1:6) eutectic solvent solution. The solution was stirred for 30 min at 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, and 80°C respectively to obtain a lead-containing eutectic solvent solution. After filtration, 100 μL of the supernatant was taken, nitrated, and diluted with 2% nitric acid. The lead ion concentration was measured by flame atomic absorption spectrometry. Figure 5 As shown, the measured lead ion concentrations were 3.501 × 10⁻⁶. 3 mg / L, 3.897×10 3 mg / L, 6.262×10 3 mg / L, 9.347×10 3 mg / L, 1.421×10 4 mg / L, 2.601×10 4 mg / L, 1.12×10 5 mg / L.

[0065] Example 8: In this example, an equimolar ratio of 1-ethyl-3-methylimidazolium iodide-ethylene glycol eutectic solvent was selected.

[0066] Excess lead iodide was dissolved in 2 mL of a eutectic solvent solution of 1-ethyl-3-methylimidazolium iodide and ethylene glycol (1:1). The solution was stirred for 30 min at 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, and 80°C, respectively, to obtain a lead-containing eutectic solvent solution. After filtration, 100 μL of the supernatant was taken, nitrated, and diluted with 2% nitric acid. The lead ion concentration was measured by flame atomic absorption spectrometry. Figure 5 As shown, the measured lead ion concentrations were 2.378 × 10⁻⁶. 4 mg / L, 2.6555×10 4 mg / L, 3.2765×10 4 mg / L, 3.891×10 4 mg / L, 4.917×10 4 mg / L, 5.163×10 4 mg / L, 6.667×10 4 mg / L.

[0067] A review of the experimental data from Examples 3-8 reveals that, with the same solvent, temperature, and stirring time, a higher amount of lead iodide added results in a higher concentration of lead ions in the system. This indicates that the solvent of the present invention has a high loading capacity and can be continuously leached by adding raw materials multiple times. Furthermore, with the same solvent, excess lead iodide, and constant stirring time, increasing the temperature continuously increases the saturated lead dissolution concentration. This pattern underscores the necessity of employing a heating and stirring operation in the leaching process of the present invention.

[0068] Simultaneously, it was found that under the same experimental conditions, the sodium iodide-ethylene glycol system exhibited superior lead-dissolving capacity and temperature-responsive dissolution improvement compared to the potassium iodide-ethylene glycol and 1-ethyl-3-methylimidazolium iodide-ethylene glycol systems, demonstrating the best lead enrichment performance. This may be related to the disruption of the sodium iodide lattice, providing a large amount of free I₂. ⁻ Decoordination of Pb 2+ Meanwhile, ethylene glycol stabilizes iodide ions through a hydrogen bond network, maintaining the liquid environment of the eutectic solvent and the solubility state of the lead-iodine complex.

[0069] To test the solubility of lead iodide by ethylene glycol and sodium iodide aqueous solution as single components, two sets of control dissolution experiments were conducted:

[0070] Control Experiment 1: Dissolving lead iodide powder with ethylene glycol alone

[0071] 2 mL of pure ethylene glycol was added to 50 mg of lead iodide powder, and the mixture was heated and stirred at 60 °C for 30 min. The lead iodide did not dissolve significantly. The supernatant was then subjected to nitration treatment and detected by flame atomic absorption spectrometry. No lead ion signal was detected.

[0072] Control Experiment 2: Dissolving lead iodide powder in sodium iodide aqueous solution alone

[0073] Prepare 2 mL of 2.7 mol / L sodium iodide aqueous solution, add 50 mg of lead iodide powder, heat and stir at 60℃ for 30 min, and the lead iodide will completely dissolve. The above phenomena indicate that excess iodide ions in the system can increase the solubility of lead iodide, and high concentrations of iodide ions can combine with PbI₂ to form [PbI₃]. - [PbI4] 2- The dissolution of iodide-lead coordination complexes relies not only on solvation but also, and more importantly, on the coordination interaction between iodide and lead ions. However, this homogeneous aqueous solution system has significant limitations: a large number of water molecules can cause the coordination equilibrium to be in an over-stable state, making it difficult to disrupt the complex structure using conventional methods, hindering the high-yield recovery of solid lead iodide, and making it difficult to recycle both the solvent and solute.

[0074] The two sets of comparative experiments above demonstrate that a single ethylene glycol solvent system cannot dissolve lead iodide at all, while sodium iodide aqueous solution can dissolve lead iodide, but it is difficult to achieve efficient recovery of lead iodide and recycling of the solvent. Neither of the two single systems can simultaneously meet the requirements of efficient dissolution of lead iodide, product recovery and solvent recycling.

[0075] To verify the molecular interaction between lead ions and iodine-based eutectic solvents, molecular dynamics simulations of the sodium iodide-ethylene glycol eutectic solvent leaching system for lead iodide were performed using Gromacs software (see [link to Gromacs software]). Figure 6 ).from Figure 6 The RDF curve results show that the hydrogen atom of the ethylene glycol hydroxyl group forms an O–H···I⁻ hydrogen bond with the iodide ion, and the oxygen atom of the ethylene glycol hydroxyl group coordinates with the sodium ion to form a solvation layer, thereby enabling the lead ion to coordinate with the iodide ion dissociated from the iodine source in the system; combined with Figure 7 The UV-Vis spectral characterization analysis shown confirms that lead ions and iodide ions form [PbI3] during the leaching process. - [PbI4] 2- Coordination complex.

[0076] In summary, this invention successfully constructs a lead-ion leaching separation and recovery process for perovskite solar cells based on an iodine-based eutectic solvent. This process operates efficiently at mild temperatures, and the eutectic solvent and anti-solvent can be recycled in a closed loop within the separation system, fundamentally eliminating the risk of secondary lead-ion leakage. This demonstrates significant environmental benefits and economic feasibility.

[0077] It should be noted that the iodine sources used in this invention include, but are not limited to, alkali metal iodides such as sodium iodide and potassium iodide, and organic iodide salts such as 1-ethyl-3-methylimidazolium iodide. The three solvents and their corresponding ratios listed in this paper are only the optimal solutions obtained by screening based on comprehensive solubility, raw material cost, and solvent cycle stability. Iodine-based eutectic solvents prepared by compounding other iodine sources with ethylene glycol can also achieve efficient recovery of lead ions from perovskite batteries according to the process of this invention, and all of them fall within the scope of protection of this invention.

Claims

1. A method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent, characterized in that, It includes the following steps: S1: The waste perovskite solar cell film is immersed in an iodine-based eutectic solvent containing hydroxyl functional groups, heated and stirred to leach out, and the solid residue is removed by solid-liquid separation to obtain a lead-containing supernatant. S2: Add antisolvent to the lead-containing supernatant to precipitate lead iodide precipitate. After solid-liquid separation, lead iodide precipitate and secondary supernatant are obtained. S3: The lead iodide precipitate is washed and dried sequentially with anhydrous ethanol and ultrapure water to obtain high-purity lead iodide crystals; S4: The secondary supernatant is separated by vacuum distillation to recover and regenerate the eutectic solvent and the antisolvent, which are then recycled for use in the leaching and precipitation processes.

2. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 1, characterized in that, During the leaching process in step S1, if the liquid lead ions in the iodine-based eutectic solvent leaching system are not saturated, waste perovskite solar cell films are continuously added for repeated leaching. After obtaining a saturated or high-concentration lead-containing solution, solid-liquid separation is then performed to obtain a lead-containing supernatant.

3. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 1, characterized in that... In step S1, the hydroxyl functional groups in the iodine-based eutectic solvent are provided by the alcohol component.

4. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 3, characterized in that... The iodine source of the iodine-based eutectic solvent includes, but is not limited to, metal iodides and 1-ethyl-3-methylimidazolium iodide.

5. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 4, characterized in that... In step S1, the iodine-based eutectic solvent is selected from any one of the following three systems: a eutectic solvent prepared by sodium iodide and ethylene glycol in a molar ratio of 1:3, a eutectic solvent prepared by potassium iodide and ethylene glycol in a molar ratio of 1:6, and a eutectic solvent prepared by 1-ethyl-3-methylimidazolium iodide and ethylene glycol in a molar ratio of 1:

1.

6. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 1, characterized in that, In step S1, the sample is heated and stirred at 30–80°C for 30 min.

7. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 1, characterized in that, In step S2, the antisolvent is ultrapure water or anhydrous ethanol.

8. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 5, characterized in that... In step S2, the volume ratio of the lead-containing supernatant to the antisolvent is 1:

5.

9. The method for rapid and green recovery of lead ions from perovskite solar cells using an iodine-based eutectic solvent as described in claim 1, characterized in that, In step S4, solvent recovery is achieved by vacuum distillation using low-pressure rotary evaporation.

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