Methods for recovering valuable materials from perovskite solar cells

Abstract

A method for recycling valuable materials from perovskite solar cells, comprising: soaking a solar cell in an organic solvent to dissolve out Cs + , Pb 2+ , Br － and I － ; adding an oxidant to oxidize I － to I2; heating to dryness to form a solid residue containing Cs + , Pb 2+ and Br － and simultaneously sublimating and recovering I2; dissolving I2 in water to form a recovered I2 solution; rinsing the solid residue with water to obtain Pb(OH)2 and a liquid phase containing Cs + , Pb 2+ and Br － ; calcining Pb(OH)2 to form PbO, or dissolving Pb(OH)2 in an HNO3 solution and then mixing with the recovered I2 solution to precipitate PbI2; mixing the liquid phase with t-BAMBP diluted with an oil phase to separate an oil phase solution containing Cs + and an aqueous phase solution containing Pb 2+ and Br － ; mixing the oil phase solution containing Cs + with an NH4OH solution to back-extract Cs + into an aqueous phase solution containing Cs + ; and adding the recovered I2 solution to the aqueous phase solution containing Cs + and then subjecting to reduced pressure concentration to precipitate CsI. The recovered PbO, PbI2 and CsI and other ternary elements are compounds of expensive precursors used for producing the absorption layer of perovskite solar panels.

Description

Technical Field

[0001] The present invention relates to a method for recovering valuable materials from solar cells, and in particular to a method for recovering valuable materials from perovskite solar cells. Background Art

[0002] The absorption layer of perovskite solar cells composed of organic metal compounds is based on its extremely high efficiency in absorbing light. After absorbing photons, it can quickly separate into electrons and holes and transfer them to the electrodes to generate current. Therefore, it has developed rapidly in the past decade and has become a candidate technology for the third generation of solar cells. Compared with the existing commercial silicon-based (Si-based) and CIGS thin-film solar cells, the adjustable energy gap, strong absorption rate, high conversion efficiency and low cost of perovskite solar cells make them quite competitive in commercialization. However, successful commercial products always inevitably bring a large amount of waste, which will eventually have an impact on the environment.

[0003] In detail, perovskite solar cells contain many valuable materials, among which lead (Pb), cesium (Cs), bromine (Br), iodine (I) and other halogen elements are not only used in solar cells, but also widely used in the electronics industry and various industrial products. In addition, lead is not only scarce in production, but also toxic to the human body. The precursor halides used to synthesize the absorption layer of perovskite solar cells are also valuable due to limited production and high purity requirements. Therefore, in order to find a way to deal with the waste of perovskite solar panels and meet the demand of the technology industry for valuable materials and the public's demand for environmental protection, perovskite solar panel related industries are constantly seeking methods to recycle valuable materials from perovskite solar cells.

[0004] For example, China's early publication patent case CN109943728A (hereinafter referred to as the former case 1) discloses a method for recovering lead in perovskite solar cells, which includes: (1) a stripping step of battery components, (2) a removal step of the hole transport layer, and (3) a step of extracting lead-containing compounds. The stripping step of the battery components in the former case 1 is to peel off the substrate material and the conductive glass by manual stripping, and then use transparent glue to gently press on the surface of the perovskite solar cell to remove the top electrode. The removal step of the hole transport layer in the former case 1 is to immerse the entire perovskite solar cell in an ethyl acetate solution and slowly stir for 1 minute, then take out the perovskite solar cell, and complete the removal of the hole transport layer after drying under a nitrogen flow. The extraction step of the lead-containing compound in the former case 1 is to immerse the surface of the perovskite solar cell in distilled water for 1 second, then take it out and place it in a small tubular heating furnace, and pass a nitrogen flow into the furnace to exhaust the air in the furnace to prevent the substances in the air in the furnace from chemically reacting with the battery. Subsequently, the small tubular heating furnace is heated to 150°C for 10 minutes, and the methylamine lead iodine (CH3NH3PbI3) in the perovskite solar cell can be decomposed into solid lead iodide (PbI2). After the heat treatment, except for the electron transport layer in the battery in the form of solid titanium dioxide (TiO2) and the lead iodide decomposed by methylamine lead iodine, the remaining substances will be converted into organic gases, which need to be collected and treated uniformly using the treatment method of organic waste gas. After the heat treatment, a solid mixture of PbI2 and TiO2 is obtained. Finally, the solid mixture is dissolved in dimethylformamide (DMF) solvent and stirred. After 2 minutes, the insoluble TiO2 solid is filtered out, and the DMF solution dissolved with PbI2 is placed in a vacuum distillation device, and the distillation temperature and vacuum pressure of the vacuum distillation device are set to 60°C and 1.3kPa respectively until it is evaporated to precipitate pure PbI2.

[0005] Another example is China's early publication invention patent case No. CN108823414A (hereinafter referred to as Case 2), which discloses a method for recycling waste perovskite solar cells. Case 2 mainly involves first immersing the perovskite solar cell in a solvent that can dissolve the perovskite material and is insoluble in other components [such as DMF, dimethyl sulfoxide (DMSO), etc.], and soaking it at a temperature of 25°C to 80°C for 5 minutes to 20 minutes to remove the substrate, wherein the solution obtained by soaking in the solvent contains the perovskite material dissolved in the solvent and the electrode material insoluble in the solvent. Next, the removed substrate is washed and then treated with ozone to remove trace organic matter on its surface for reuse. Next, the solution obtained by soaking is subjected to solid-liquid separation processes such as centrifugation and filtration to obtain a lead-containing leachate. Ammonia water is further added to the lead-containing leachate to react so that the Pb in the lead-containing leachate is 2+After the precipitation of Pb(OH)2 and the first turbid liquid is obtained, the first turbid liquid is subjected to solid-liquid separation to obtain a first solid. Next, the obtained first solid is reacted with dilute acetic acid (CH3COOH) to obtain a second turbid liquid, and the second turbid liquid is subjected to solid-liquid separation to obtain a Pb(CH3COO)2 solid. Finally, the obtained Pb(CH3COO)2 solid is dried to obtain a Pb(CH3COO)2 solid with a purity of more than 99.9%.

[0006] The pure PbI2 precipitated by evaporation in Case 1 and the high-purity Pb(CH3COO)2 solid obtained by drying in Case 2 are both used as precursors for synthesizing the absorption layer of perovskite solar cells. Although raw materials such as PbI2 and Pb(CH3COO)2 can be recovered, only binary elements Pb and I can be obtained at most from the recovered raw materials. However, elements such as cesium (Cs) and bromine (Br) in the absorption layer of perovskite solar cells are also of great value to related industries in the relevant technical fields.

[0007] It can be seen from the above description that recovering valuable materials of at least ternary elements from perovskite solar cells for effective utilization by related industries in the technical field and saving material costs is a topic that needs to be continuously broken through by relevant technical personnel in the technical field to which this application belongs. Summary of the invention

[0008] The object of the present invention is to provide a method for recovering valuable materials from perovskite solar cells which can simultaneously recover at least ternary elements.

[0009] The method of the present invention for recovering valuable materials from a perovskite solar cell comprises the following steps: step (a), step (b), step (c), step (d), step (e), step (f), step (g), step (h), and step (i).

[0010] The step (a) is to immerse the perovskite solar cell panel in an organic solvent to separate an absorption layer, a carrier transport layer and a transparent conductive layer containing at least one monovalent metal cation, at least one divalent metal cation and at least two halogen anions from the perovskite solar cell panel, so that the monovalent metal cation, divalent metal cation and halogen anions of the absorption layer are dissolved in the organic solvent.

[0011] The step (b) is to add an oxidant to the organic solvent to form a mixed solution after the step (a), so as to oxidize one of the two halogen anions into a halogen molecule.

[0012] The step (c) is to heat the mixed solution after the step (b) to sublime and recover the halogen molecules in the mixed solution until the mixed solution dries up to become a solid residue containing the monovalent metal cation, the divalent metal cation and a residual halogen anion.

[0013] The step (d) is to dissolve the halogen molecules in deionized water to obtain a recovered halogen solution after the step (c).

[0014] The step (e) is to wash the solid phase residue with deionized water after the step (c) to obtain a solid phase containing the divalent metal cation and a liquid phase containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion.

[0015] The step (f) is to calcine the solid phase containing the divalent metal cations to form metal oxides after the step (e), or to dissolve the solid phase containing the divalent metal cations in an aqueous solution and then mix it with the recovered halogen solution to precipitate metal halides.

[0016] The step (g) is to mix the liquid phase of the step (e) with the extractant diluted with the oil phase, thereby separating the oil phase solution containing the monovalent metal cation and the water phase solution containing the divalent metal cation and the remaining halogen anion.

[0017] The step (h) is to mix the oil phase solution containing the monovalent metal cation with an ammonium hydroxide (NH4OH) aqueous solution after the step (g) to strip the monovalent metal cation in the oil phase solution into an aqueous solution containing the monovalent metal cation.

[0018] The step (i) is to add the recovered halogen solution to the aqueous solution containing the monovalent metal cation after the step (h), and then concentrate under reduced pressure to precipitate another metal halide.

[0019] In the present invention, the extractant is 4-tert-butyl-2-(α-methylbenzyl)phenol [4-tert-butyl-2-(α-methylbenzyl)-phenol, hereinafter referred to as t-BAMBP].

[0020] The method for recovering valuable materials from perovskite solar cells of the present invention further comprises a step (j) after the step (i), wherein the step (j) is to concentrate the aqueous solution containing the divalent metal cations and the remaining halogen anions under reduced pressure to obtain another metal halide.

[0021] In the method for recovering valuable materials from perovskite solar cells of the present invention, the absorber layer of the perovskite solar cell panel in step (a) is degraded, and the absorber layer has a structural formula selected from the group consisting of: CsPbBr X I 3-X 、CsMAFAPb(Br X I 1-X )3, and the combination of the aforementioned structural formula, the monovalent metal cation and the divalent metal cation are Cs + With Pb 2+ , and one of the halogen anions and the remaining halogen anions are respectively － With Br － .

[0022] The method for recovering valuable materials from perovskite solar cells of the present invention comprises the following steps: the organic solvent in step (a) is dimethylformamide, the oxidant in step (b) is hydrogen peroxide, and the solid residue containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion in step (c) contains Cs + , Pb 2+ With Br － The halogen molecules sublimated and recovered in step (c) are I2 vapor; and the step (d) is to dissolve the I2 vapor in deionized water, and the recovered halogen solution is an I2 solution.

[0023] In the method for recovering valuable materials from a perovskite solar cell of the present invention, in the step (e), the obtained solid phase containing the divalent metal cation contains Pb(OH)2, and the obtained liquid phase containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion contains Cs + , Pb 2+ With Br － .

[0024] In the method for recovering valuable materials from perovskite solar cells of the present invention, when the step (f) is carried out after calcination, the metal oxide is PbO; when the step (f) is carried out by dissolving in the aqueous solution, the aqueous solution of the step (f) is an aqueous nitric acid solution, and the metal halide precipitated after mixing with the recovered I2 solution is PbI2.

[0025] The method for recovering valuable materials from perovskite solar cells of the present invention, in the step (g), the extractant is diluted with kerosene, the concentration of the extractant is between 0.001 mol / L and 0.4 mol / L, the pH value is between 5 and 8, the oil phase-water phase ratio is between 0.1 and 2.0, the implementation time is less than or equal to 20 minutes, and the separated oil phase solution containing monovalent metal cations contains Cs +, and the aqueous solution containing the divalent metal cation and the remaining halogen anion contains Pb 2+ With Br － .

[0026] In the method for recovering valuable materials from perovskite solar cells of the present invention, in step (h), the concentration of the aqueous ammonium hydroxide solution is between 0.1 mol / L and 2.0 mol / L, and the Cs + The oil phase solution-ammonium hydroxide aqueous solution ratio is less than or equal to 2.0, the implementation time is between 5 minutes and 25 minutes, and the aqueous solution containing monovalent metal cations after stripping contains Cs + In step (i), the Cs + The other metal halide precipitated by concentrating the aqueous solution and the recovered I2 solution under reduced pressure is CsI.

[0027] The method for recovering valuable materials from perovskite solar cells of the present invention further comprises a step (j) after the step (i), wherein the step (j) is to reduce the pressure and concentrate the Pb-containing 2+ With Br － of aqueous solution to obtain PbBr2.

[0028] The beneficial effects of the present invention are as follows: the metal oxide (PbO) or the metal halide (PbI2) can be obtained in the step (f) to preliminarily recover the valuable material of the binary element, the other metal halide (CsI) can be further obtained in the step (i), and (PbBr2) can be recovered in the step (j). The integration of the aforementioned steps (f), (i) and (j) can recover the valuable material of the quaternary element. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0030] Figure 1 is a schematic diagram illustrating a step (a) of an embodiment of a method for recovering valuable materials from a perovskite solar cell of the present invention;

[0031] Figure 2 is a schematic diagram illustrating a step (b) of the recycling method of this embodiment of the present invention;

[0032] Figure 3 is a schematic diagram illustrating a step (c) of the recycling method of this embodiment of the present invention;

[0033] Figure 4 is a schematic diagram illustrating a step (d) of the recycling method of this embodiment of the present invention;

[0034] Figure 5 is a schematic diagram illustrating a step (e) of the recycling method of this embodiment of the present invention;

[0035] Figure 6 is a schematic diagram illustrating a step (f) of the recycling method of this embodiment of the present invention;

[0036] Figure 7 is a schematic diagram illustrating a step (g) of the recycling method of this embodiment of the present invention;

[0037] Figure 8 is a schematic diagram illustrating a step (h) of the recycling method of this embodiment of the present invention;

[0038] Fig. 9 is a schematic diagram illustrating a step (i) of the recycling method of this embodiment of the present invention; and

[0039] Fig.10 is a schematic diagram illustrating a step (j) of the recovery method of this embodiment of the present invention. DETAILED DESCRIPTION

[0040] An embodiment of the method of recovering valuable materials from perovskite solar cells of the present invention comprises the following steps: a step (a), a step (b), a step (c), a step (d), a step (e), a step (f), a step (g), a step (h), and a step (i).

[0041] See also Figure 1 The step (a) is to immerse a perovskite solar cell panel 2 in an organic solvent 3 to separate an absorption layer 21 containing at least one monovalent metal cation, at least one divalent metal cation and at least two halogen anions, and a carrier transport layer (ETL) / transparent conductive layer 22 from the perovskite solar cell panel 2, so that the monovalent metal cations, divalent metal cations and halogen anions of the absorption layer 21 are dissolved in the organic solvent 3.

[0042] See also Figure 2 The step (b) is to add an oxidant 4 to the organic solvent 3 to form a mixed solution 30 after the step (a) to oxidize one of the two halogen anions into a halogen molecule 5.

[0043] See also Figure 3 The step (c) is to heat the mixed solution 30 after the step (b) to sublime and recover the halogen molecules 5 in the mixed solution 30 until it dries up to form a solid residue 6 containing the monovalent metal cation, the divalent metal cation and a residual halogen anion.

[0044] See also Figure 4 The step (d) is to dissolve the halogen molecule 5 in deionized water to form a recovered halogen solution 51 after the step (c).

[0045] See also Figure 5 The step (e) is to wash the solid phase residue 6 with deionized water after the step (c) to obtain a solid phase 61 containing the divalent metal cation and a liquid phase 62 containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion.

[0046] See also Figure 6 The step (f) is to calcine the solid phase 61 containing the divalent metal cation to form a metal oxide 81 after the step (e), or to dissolve the solid phase 61 containing the divalent metal cation in an aqueous solution and then mix it with the recovered halogen solution 51 to precipitate a metal halide 82.

[0047] See also Figure 7 The step (g) is to mix the liquid phase 62 containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion in the step (e) with an extractant 71 diluted with an oil phase, thereby separating an oil phase solution 711 containing the monovalent metal cation and an aqueous phase solution 712 containing the divalent metal cation and the remaining halogen anion. In the present invention, the extractant 71 is t-BAMBP.

[0048] See also Figure 8 The step (h) is to mix the oil phase solution 711 containing the monovalent metal cation with an ammonium hydroxide (NH4OH) aqueous phase solution 72 after the step (g) to strip the monovalent metal cation in the oil phase solution 711 into an aqueous phase solution 7111 containing the monovalent metal cation.

[0049] See also Fig. 9 The step (i) is to add the recovered halogen solution 51 to the aqueous solution 7111 containing the monovalent metal cation after the step (h), and then concentrate under reduced pressure to precipitate another metal halide 83.

[0050] Preferably, if Fig.10 As shown, the recovery method of this embodiment of the present invention further comprises a step (j) after the step (i). The step (j) is to concentrate the aqueous phase solution 712 containing the divalent metal cations and the remaining halogen anions under reduced pressure to obtain another metal halide 84.

[0051] In this embodiment of the present invention, the absorber layer 21 of the perovskite solar cell panel 2 in step (a) is degraded, and the absorber layer 21 before degradation has a structural formula selected from the group consisting of: CsPbBrX I 3-X 、CsMAFAPb(Br X I 1-X )3, and a combination of the above structural formulas; therefore, the monovalent metal cation and the divalent metal cation are each Cs + With Pb 2+ , and one of the halogen anions and the remaining halogen anions are each I － With Br － .

[0052] The organic solvent 3 suitable for the step (a) of the present invention can be dimethylformamide (DMF); the oxidant 4 of the step (b) can be Figure 2 Hydrogen peroxide (H2O2) is shown, but not limited to.

[0053] In this embodiment of the present invention, the solid phase residue 6 containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion in step (c) is as follows: Figure 3 As shown, containing Cs + , Pb 2+ With Br － The halogen molecule 5 sublimated and recovered in step (c) is as follows Figure 3 The step (d) is to dissolve the I2 vapor in deionized water, and the recovered halogen solution 51 is an I2 solution. Figure 5 In step (e) of the embodiment of the present invention, the obtained solid phase 61 containing the divalent metal cation contains Pb(OH)2, and the obtained liquid phase 62 containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion contains Cs + , Pb 2+ With Br － .

[0054] Furthermore, in this embodiment of the present invention, when the step (f) is performed after calcination, the metal oxide 81 is as follows Figure 6 When the step (f) is carried out by dissolving in the aqueous solution, the aqueous solution of the step (f) is a nitric acid (HNO3) aqueous solution, and the metal halide 82 precipitated by mixing with the recovered I2 solution is as follows Figure 6 Lead iodide (PbI2) shown.

[0055] Preferably, in step (g), the extractant (t-BAMBP) 71 is diluted with kerosene. More preferably, in step (g), the concentration of the extractant 71 is between 0.001 mol / L and 0.4 mol / L, the pH value is between 5 and 8, the oil phase-water phase ratio is between 0.1 and 2.0, and the implementation time is less than or equal to 20 minutes. In step (g) of this embodiment of the present invention, the separated oil phase solution 711 containing monovalent metal cations contains Figure 7 Cs shown + , and the aqueous phase solution 712 containing divalent metal cations and the remaining halogen anions contains Figure 7 Pb shown 2+ With Br － .

[0056] Preferably, in step (h), the concentration of the aqueous ammonium hydroxide solution 72 is between 0.1 mol / L and 2.0 mol / L. + The oil phase solution 711-ammonium hydroxide aqueous phase solution 72 ratio is less than or equal to 2.0, and the implementation time is between 5 minutes and 25 minutes. In step (h) of this embodiment of the present invention, the aqueous phase solution 7111 containing monovalent metal cations after stripping, such as Figure 8 Shown to contain Cs + Furthermore, in step (i) of this embodiment of the present invention, the + The other metal halide 83 precipitated by the aqueous solution 7111 and the recovered I2 solution 51 after reduced pressure concentration is as follows Fig. 9 The cesium iodide (CsI) shown in the embodiment of the present invention is concentrated under reduced pressure to 2+ With Br － The aqueous solution 712 is obtained as Fig.10 Lead bromide (PbBr2) shown.

[0057] <Raw materials used in specific examples>

[0058] Six perovskite solar panels were exposed to the atmosphere for 6 months and degraded, each having a film structure of glass / ITO / SnO2 / electron transport layer (ETL) / absorber layer; wherein the absorber layer had the structural formula CsPbBr as described above before degradation. X I 3-X And the structural formula CsMAFAPb(Br X I 1-X )3, and each absorbent layer has a size of 1.5 cm×1.5 cm×0.02 cm.

[0059] The organic solvent 3 used in step (a) is DMF purchased from JTBaker and has a concentration of 99.8%. The oxidant 4 used in step (b) is H2O2 purchased from Simga-Aldrich and has a concentration of 34.5-36.5%. The aqueous phase solution used in step (f) is HNO3 purchased from Sigma-Aldrich; wherein the HNO3 aqueous solution with a concentration of 5 mol / L is prepared with a liquid-to-solid ratio of 100. The extractant 71 used in step (g) is t-BAMBP purchased from Beijing Ruilekang Separation Technology Co., Ltd., and the oil phase is kerosene purchased from CPC Corporation of Taiwan, China. The NH4OH used in step (h) is NH4OH purchased from Sigma-Aldrich.

[0060] <Specific example>

[0061] First, see Figure 1 The degraded solar cell panels 2 were immersed in 10 mL of DMF for about 5 minutes to separate the degraded absorption layer [CsPbBr X I 3-X and CsMAFAPb(Br X I 1-X )3]21, electron transport layer (ETL) and ITO / SnO2, so that the Cs 21 in the absorption layer + , Pb 2+ ,I － With Br － Dissolved in DMF.

[0062] The DMF solution obtained after soaking in DMF in this specific example of the present invention was analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES) and ion chromatography (IC), showing that the DMF solution was composed of 35.38wt% Pb, 22.28wt% Cs, 24.92wt% I and 17.42wt% Br.

[0063] Since I2 can easily sublime into gas; － With Br － Compared with the two, I － The reducing power is greater than that of Br － Therefore, the applicant chose to add an oxidant (H2O2) into the DMF solution to separate I2 from the DMF solution.

[0064] like Figure 2As shown, H2O2 is added to the DMF solution at a water-organic phase (H2O2-DMF) ratio of 0.1 to form a mixed solution 30, so as to － Oxidized to I2.

[0065] Then, if Figure 3 As shown, the mixed solution 30 is heated at 58°C to sublime the I2 in the mixed solution 30 into I2 vapor and recovered, and the mixed solution 30 is continuously heated at 100°C until it dries up to become a mixture containing Cs + , Pb 2+ With Br － Solid residue 6.

[0066] Afterwards, if Figure 4 As shown, I2 vapor is dissolved in deionized water to form a recovered I2 solution 51. In this specific example of the present invention, the recovered I2 solution 51 is composed of 0.04wt% Pb, 99.8wt% I and 0.02wt% Br according to IC analysis, and the recovery rate of I2 is 79.19% after conversion.

[0067] In addition, given that the + , Pb 2+ With Br － Cs in the solid residue 6 + It is an alkali metal element that is very soluble in water. Therefore, the applicant further rinsed it with deionized water. Figure 4 The Cs + , Pb 2+ With Br － The solid residue 6 is obtained as Figure 5 The solid phase 61 shown contains a Pb(OH)2 and a Cs + , Pb 2+ With Br － In this embodiment of the present invention, the solid phase 61 of Pb(OH)2 is composed of 94.5wt% Pb, 4.22wt% I and 1.28wt% Br by ICP-OES analysis. + , Pb 2+ With Br － IC analysis shows that the liquid phase 62 is composed of 4.01 wt % Pb, 53.85 wt % Cs and 41.12 wt % Br.

[0068] Subsequently, two methods can be used to recover the Pb element in the Pb(OH)2 solid phase 61. For example, the Pb(OH)2 solid phase 61 is calcined to form Figure 6The PbO powder 81 shown in the figure can be used to recover the precursor of the Pb element used to produce the absorption layer. Alternatively, the Pb(OH)2 solid phase 61 is first dissolved in an HNO3 aqueous solution and then mixed with Figure 4 The recovered I2 solution 51 shown is mixed to precipitate Figure 6 The PbI2 powder 82 shown in the figure can also be used to recover the precursors of binary elements such as Pb and I used to produce the absorption layer. In this specific example of the present invention, the XRD analysis results of both the PbO powder 81 and the PbI2 powder 82 after dehydration at below 600°C show that they all have excellent crystalline phase diffraction signal peaks (not shown in the figure); in addition, the PbO powder 81 is analyzed by ICP-OES and shows that it is composed of 98.9wt% Pb, 0.39wt% Ca and 0.71wt% Na, and the Pb recovery rate is 95.2% after conversion, while the PbI2 powder 82 is analyzed by ICP-OES and shows that it is composed of 99.7wt% Pb, 0.17wt% Ca and 0.13wt% Na, and the Pb recovery rate is 95.3% after conversion.

[0069] About the Cs + , Pb 2+ With Br － The liquid phase 62 (see Figure 5 ), then Figure 7 As shown in the figure, it was mixed with t-BAMBP diluted with glycerol, and the mol / L concentration of t-BAMBP (0.001, 0.01, 0.1, 0.2 and 0.4), pH value (5, 6, 7, 8, 9 and 10), oil phase-water phase ratio (0.1, 0.25, 0.5, 1 and 2), and mixing time (0.5 min, 3 min, 5 min, 10 min, 15 min and 20 min) were controlled to separate (extract) a Cs-containing + The oil phase solution 711 and a Pb 2+ With Br － of aqueous solution 712. In this specific example of the present invention, the oil-water phase ratio does not change much for the Cs extraction rate, and the Cs extraction rate increases with the increase of pH value, t-BAMBP mol / L concentration and mixing time; wherein, the pH value, t-BAMBP mol / L concentration and mixing time corresponding to the optimization of Cs extraction rate are 8, 0.2 mol / L and 15 minutes, respectively.

[0070] Then, if Figure 8 As shown, the mixture containing Cs + The oil phase solution 711 and an NH4OH aqueous phase solution 72 are controlled to have a mol / L concentration (0.1, 0.2, 0.3, 0.5, 1 and 2) of the NH4OH aqueous phase solution 72.+ The ratio of the oil phase solution 711 to the NH4OH aqueous solution 72 (0.5, 1, 2 and 4), and the mixing time (5 minutes, 10 minutes, 15 minutes, 20 minutes and 25 minutes) were adjusted to make the Cs in the oil phase solution 711 + Stripping to a Cs + In this specific example of the present invention, the stripping rate of Cs increases with the increase of the mol / L concentration of the NH4OH aqueous solution 72 and the mixing time, and the stripping rate of Cs increases with the increase of the NH4OH aqueous solution 72 containing Cs. + The oil phase solution 711-NH4OH aqueous phase solution 72 ratio increases with the decrease; wherein the mol / L concentration of the NH4OH aqueous phase solution 72, the Cs + The ratio of the oil phase solution 711 to the NH4OH aqueous phase solution 72 and the mixing time corresponding to the optimization of the Cs stripping rate are 1 mol / L, 0.5 and 20 minutes respectively.

[0071] In the stripping of the Cs + After 7111 of aqueous solution, Fig. 9 As shown, in the + After the recovered I2 solution 51 is added to the aqueous solution 7111, a CsI powder 83 is precipitated by vacuum concentration, so that the precursors of binary elements such as Cs and I used to produce the absorption layer can be recovered. In this specific example of the present invention, the XRD analysis results of the CsI powder 83 show that it has excellent crystalline phase diffraction signal peaks; in addition, the ICP-OES analysis of the CsI powder 83 shows that it is composed of 0.05wt% Pb, 99.83wt% Cs, 0.08wt% Ca and 0.04wt% Na, and the recovery rate of Cs is 99.7% after conversion.

[0072] Finally, if Fig.10 As shown, concentrated under reduced pressure Figure 7 The Pb 2+ With Br －The aqueous solution 712 is then used to obtain a PbBr2 powder 84, so that the precursors of binary elements such as Pb and Br used to produce the absorption layer can be recovered. In this specific example of the present invention, the XRD analysis results of the PbBr2 powder 84 show that it has a diffraction signal peak of a crystalline phase; in addition, the ICP-OES analysis of the PbBr2 powder 84 shows that it is composed of 99.58wt% Pb, 0.2wt% Ca and 0.22wt% Na, and the Pb recovery rate is about 4.67%. By further adding the previously obtained PbO powder 81 (Pb recovery rate of 95.2%) and the PbBr2 powder 84 obtained here (Pb recovery rate of about 4.67%), a Pb recovery rate of about 99.87% can be obtained. By adding the previously obtained PbI2 powder 82 (Pb recovery rate of 95.3%) and the PbBr2 powder 84 obtained here (Pb recovery rate of about 4.67%), a Pb recovery rate of about 99.97% can be obtained.

[0073] In summary, the method of recovering valuable materials from perovskite solar cells of the present invention can recover quaternary element powders such as PbO powder 81, PbI2 powder 82, CsI powder 83 and PbBr2 powder 84 from the absorption layer 21 of the perovskite solar cell panel 2. These powders are all expensive precursors for producing the absorption layer of the perovskite solar cell, so the purpose of the present invention can be achieved.

[0074] The above is only an embodiment of the present invention and should not be used to limit the scope of the present invention. All simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A method for recovering valuable materials from perovskite solar cells, characterized in that: It contains the following steps: Step (a) is to immerse the perovskite solar cell panel in an organic solvent to separate an absorption layer containing at least one monovalent metal cation, at least one divalent metal cation and at least two halogen anions, a carrier transport layer and a transparent conductive layer from the perovskite solar cell panel, so that the monovalent metal cation, divalent metal cation and halogen anion of the absorption layer are dissolved in the organic solvent; Step (b) is to add an oxidant to the organic solvent to form a mixed solution after step (a) to oxidize one of the two halogen anions into a halogen molecule; Step (c) is to heat the mixed solution after step (b) to sublimate and recover the halogen molecules in the mixed solution until the mixed solution dries up to form a solid residue containing the monovalent metal cation, the divalent metal cation and a residual halogen anion; Step (d), after step (c), dissolving the halogen molecules in deionized water to obtain a recovered halogen solution; Step (e) is to wash the solid phase residue with deionized water after step (c) to obtain a solid phase containing the divalent metal cation and a liquid phase containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion; Step (f) is to calcine the solid phase containing the divalent metal cation to form a metal oxide after step (e), or dissolve the solid phase containing the divalent metal cation in an aqueous solution and then mix it with the recovered halogen solution to precipitate a metal halide; Step (g) is to mix the liquid phase containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion in step (e) with the extractant diluted with the oil phase, thereby separating the oil phase solution containing the monovalent metal cation and the aqueous phase solution containing the divalent metal cation and the remaining halogen anion; Step (h), after step (g), mixing the oil phase solution containing the monovalent metal cation with an aqueous solution of ammonium hydroxide to strip the monovalent metal cation in the oil phase solution into an aqueous solution containing the monovalent metal cation; and Step (i) is to add the recovered halogen solution to the aqueous solution containing the monovalent metal cation after step (h), and then concentrate under reduced pressure to precipitate another metal halide; Wherein, the extractant is 4-tert-butyl-2-(α-methylbenzyl)phenol.

2. The method for recovering valuable materials from perovskite solar cells according to claim 1, characterized in that: The method further comprises a step (j) after the step (i), wherein the step (j) is to concentrate the aqueous solution containing the divalent metal cation and the remaining halogen anion under reduced pressure to obtain another metal halide.

3. The method for recovering valuable materials from perovskite solar cells according to claim 1, characterized in that: The absorber layer of the perovskite solar cell panel in step (a) is degraded, and the absorber layer before degradation has a structural formula selected from the group consisting of: CsPbBr X I 3-X 、CsMAFAPb(Br X I 1-X )3, and the combination of the aforementioned structural formula, the monovalent metal cation and the divalent metal cation are Cs ＋ With Pb 2＋ , and one of the halogen anions and the remaining halogen anions are respectively － With Br － .

4. The method for recovering valuable materials from perovskite solar cells according to claim 3, characterized in that: The organic solvent in step (a) is dimethylformamide, the oxidant in step (b) is hydrogen peroxide, and the solid residue containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion in step (c) contains Cs ＋ , Pb 2＋ With Br － The halogen molecules sublimated and recovered in step (c) are I2 vapor; and the step (d) is to dissolve the I2 vapor in deionized water, and the recovered halogen solution is an I2 solution.

5. The method for recovering valuable materials from perovskite solar cells according to claim 4, characterized in that: In step (e), the obtained solid phase containing the divalent metal cation contains Pb(OH)2, and the obtained liquid phase containing the monovalent metal cation, the divalent metal cation and the remaining halogen anion contains Cs ＋ , Pb 2＋ With Br － .

6. The method for recovering valuable materials from perovskite solar cells according to claim 5, characterized in that: When step (f) is performed after calcination, the metal oxide is PbO; when step (f) is performed by dissolving in the aqueous solution, the aqueous solution of step (f) is an aqueous nitric acid solution, and the metal halide precipitated after mixing with the recovered I2 solution is PbI2.

7. The method for recovering valuable materials from perovskite solar cells according to claim 6, characterized in that: In step (g), the extractant is diluted with kerosene, the concentration of the extractant is between 0.001 mol / L and 0.4 mol / L, the pH value is between 5 and 8, the oil phase-water phase ratio is between 0.1 and 2.0, the implementation time is less than or equal to 20 minutes, and the separated oil phase solution containing monovalent metal cations contains Cs ＋ , and the aqueous solution containing the divalent metal cation and the remaining halogen anion contains Pb 2＋ With Br － .

8. The method for recovering valuable materials from perovskite solar cells according to claim 7, characterized in that: In step (h), the concentration of the aqueous ammonium hydroxide solution is between 0.1 mol / L and 2.0 mol / L. ＋ The oil phase solution-ammonium hydroxide aqueous solution ratio is less than or equal to 2.0, the implementation time is between 5 minutes and 25 minutes, and the aqueous solution containing monovalent metal cations after stripping contains Cs ＋ ; In step (i), the Cs ＋ The other metal halide precipitated by concentrating the aqueous solution and the recovered I2 solution under reduced pressure is CsI.

9. The method for recovering valuable materials from perovskite solar cells according to claim 7, characterized in that: After step (i), the method further comprises step (j), wherein step (j) is to reduce the pressure and concentrate the Pb-containing 2＋ With Br － of aqueous solution to obtain PbBr2.

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