Self-repairing polyurethane additive for perovskite battery as well as preparation method and application of self-repairing polyurethane additive

Abstract

The invention provides a self-repairing polyurethane additive for a perovskite battery and a preparation method and application of the self-repairing polyurethane additive, and belongs to the field of high polymer materials, the self-repairing polyurethane additive for the perovskite battery comprises the following preparation raw materials: diisocyanate, polyalcohol, a chain extender, an end-capping reagent, a catalyst, a polymerization inhibitor and a COF material, the chain extender is micromolecular dihydric alcohol, and the end-capping reagent is selected from any one or a combination of at least two of 1, 4-benzoquinone dioxime, 4-hydroxyacetophenone oxime, acetaldehyde oxime, acetoxime or cyclohexanone oxime. The self-repairing polyurethane additive disclosed by the invention is used in the perovskite film and can effectively self-repair cracks generated by stretching at a grain boundary, so that the service life of a battery is prolonged, the safety is enhanced and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and relates to a self-healing polyurethane additive for perovskite solar cells, a preparation method thereof, and an application thereof. Background Art

[0002] Perovskite solar cells are a new type of photovoltaic device based on perovskite-structured materials (usually having the chemical formula ABX3, where A is a large organic cation or inorganic cation, B is a metal cation, and X is a halogen anion). The core material perovskite has excellent optoelectronic properties, such as a high absorption coefficient, a long carrier diffusion length, and an adjustable bandgap, making it show great application potential in the photovoltaic field.

[0003] The preparation processes of perovskite thin films mainly include coating methods, evaporation methods, inkjet printing, etc. Among them, the coating method is the most mainstream process at present, which has the advantages of low cost and high efficiency, but there are stability problems. For example, cracks or perforations may occur during the drying and crystallization processes after coating. The reasons for cracks and perforations include defects at the crystallization interface caused by the nucleation and crystallization processes, the reduction of crystallization quality brought by solvents and annealing processes, and the degradation of perovskite caused by the external environment such as water and air, thus forming crystallization defects.

[0004] Therefore, in this field, it is desirable to develop materials for solving the above-mentioned problems. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a self-healing polyurethane additive for perovskite solar cells, a preparation method thereof, and an application thereof.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a self-healing polyurethane additive for perovskite solar cells. The raw materials for preparing the self-healing polyurethane additive for perovskite solar cells include diisocyanate, polyol, chain extender, capping agent, catalyst, inhibitor, and COF material. The chain extender is a small molecule diol, and the capping agent is selected from any one or a combination of at least two of 1,4-benzoquinone dioxime, 4-hydroxyacetophenone oxime, acetaldehyde oxime, acetone oxime, or cyclohexanone oxime.

[0008] In the present invention, the self-healing polyurethane prepared from the above-prepared raw materials contains dynamic oxime carbamate bonds in its structure. The reaction between the oxime group and the carbamate is thermally reversible and can undergo a process of cleavage and recombination under external stimuli (such as temperature change, ultraviolet light irradiation, mechanical stress, etc.), enabling it to restore its original structure when damaged, restore the integrity and function of the material, thereby improving the conductivity and carrier mobility of the perovskite film. Moreover, a COF material is introduced into its structure to avoid affecting the conductivity of the perovskite during the repair process and not affecting the photoelectric conversion efficiency of the perovskite solar cell.

[0009] Aiming at the inherent brittleness of the perovskite layer in the perovskite solar cell, the existence of residual tensile strain, and the high-density defects along the perovskite grain boundaries, the polyurethane additive of the present invention can endow the perovskite film with self-healing performance, and can effectively self-repair the cracks generated by stretching at the grain boundaries, thereby extending the service life of the battery, enhancing safety and reducing maintenance costs.

[0010] Preferably, the diisocyanate is one or a combination of at least two of diphenylmethane diisocyanate, m-xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0011] Preferably, the polyol is one or a combination of at least two of polycaprolactone diol, polycarbonate diol, polyoxyethylene ether diol, and polytetrahydrofuran ether diol.

[0012] Preferably, the number-average molecular weight of the polyol is 1000 - 2000, such as 1000, 1200, 1400, 1600, 1800, or 2000.

[0013] Preferably, the chain extender is one or a combination of at least two of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and neopentyl glycol.

[0014] Preferably, the catalyst is selected from dibutyltin dilaurate and / or bismuth laurate.

[0015] Preferably, the inhibitor is selected from BHT (2,6-di-tert-butyl-4-methylphenol) or MEHQ (p-methoxyphenol).

[0016] Preferably, the COF material is selected from EB-COF:Br and / or TpPa-SO3H.

[0017] In the present invention, during the spin coating of perovskite in the preparation of perovskite solar cells, defects will occur between crystals. The self-healing polyurethane resin of the present invention is used to improve such defects. However, since the conductivity of perovskite will also be affected during the repair process of polyurethane resin, a COF structure is introduced into its structure, thus completely solving the problem of perovskite materials.

[0018] Preferably, the molar ratio of diisocyanate to polyol in the preparation raw materials is 1:0.5 - 0.7, such as 1:0.5, 1:0.53, 1:0.55, 1:0.58, 1:0.6, 1:0.65, 1:0.68 or 1:0.7.

[0019] Preferably, the molar ratio of diisocyanate to chain extender in the preparation raw materials is 1:0.2 - 0.4, such as 1:0.2, 1:0.23, 1:0.25, 1:0.28, 1:0.3, 1:0.35, 1:0.38 or 1:0.4.

[0020] Preferably, the molar ratio of diisocyanate to capping agent in the preparation raw materials is 1:0.1 - 0.3, such as 1:0.1, 1:0.13, 1:0.15, 1:0.18, 1:0.2, 1:0.23, 1:0.25, 1:0.28 or 1:0.3.

[0021] Preferably, the dosage of the catalyst in the preparation raw materials is 0.05% - 1% of the mass of diisocyanate, such as 0.05%, 0.07%, 0.09%, 0.1%, 0.3%, 0.5%, 0.8% or 1%.

[0022] Preferably, the dosage of the inhibitor in the preparation raw materials is 0.05% - 0.2% of the mass of diisocyanate, such as 0.05%, 0.07%, 0.09%, 0.1%, 0.15%, 0.18% or 0.2%.

[0023] Preferably, the COF material in the preparation raw materials is 3% - 9% of the total mass of the preparation raw materials, such as 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5% or 9%.

[0024] On the other hand, the present invention provides a method for preparing the self-healing polyurethane additive for perovskite solar cells as described above. The preparation method includes the following steps:

[0025] (1) React polyol, chain extender and diisocyanate in the presence of a catalyst and an inhibitor;

[0026] (2) Add a capping agent to the reaction system obtained in step (1) and react;

[0027] (3) Add COF material to the product obtained in step (2) and mix to obtain the self-healing polyurethane additive for perovskite cells.

[0028] Preferably, the reaction in step (1) is carried out under anhydrous conditions.

[0029] Preferably, the temperature of the reaction in step (1) is 40 - 80 °C, such as 40 °C, 45 °C, 48 °C, 50 °C, 55 °C, 58 °C, 60 °C, 65 °C, 68 °C, 70 °C, 75 °C, 78 °C or 80 °C, and the reaction time is 1 - 10 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h.

[0030] Preferably, the temperature of the reaction in step (2) is 60 - 80 °C, such as 60 °C, 65 °C, 68 °C, 70 °C, 75 °C, 78 °C or 80 °C, and the reaction time is 2 - 8 h, such as 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h.

[0031] Preferably, the mixing in step (3) is carried out at a temperature of 60 - 70 °C (such as 60 °C, 63 °C, 65 °C, 68 °C or 70 °C), and the mixing time is 6 - 10 h, such as 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h or 10 h.

[0032] On the other hand, the present invention provides a perovskite precursor, which comprises the self-healing polyurethane additive for perovskite cells as described above.

[0033] In the present invention, the addition amount of the self-healing polyurethane additive for perovskite cells in the perovskite precursor is 1 - 5 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%.

[0034] On the other hand, the present invention provides a perovskite thin film, which is prepared from the perovskite precursor as described above.

[0035] On the other hand, the present invention provides a perovskite cell, which comprises the perovskite thin film as described above.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The structure of the self-healing polyurethane additive of the present invention contains dynamic oxime carbamate bonds. The reaction between the oxime group and the carbamate is thermally reversible and can undergo a process of cleavage and recombination under external stimuli (such as temperature change, ultraviolet light irradiation, mechanical stress, etc.), enabling it to restore its original structure when damaged, restore the integrity and function of the material, thereby improving the conductivity and carrier mobility of the perovskite film. Moreover, a COF material is introduced into its structure to avoid affecting the conductivity of the perovskite during the repair process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the infrared spectrum of the product obtained in step (1) of Example 1.

[0039] Figure 2 It is the infrared spectrum of the product obtained in step (2) of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0040] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0041] Example 1

[0042] This example provides a self-healing polyurethane additive for perovskite batteries, and its preparation method includes the following steps:

[0043] (1) Polycaprolactone diol (molecular weight 1000, purchased from Daicel Japan), chain extender ethylene glycol, and diphenylmethane diisocyanate react at 60 °C under anhydrous conditions for 5 h in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.1% of the mass of diphenylmethane diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of phenylmethane diisocyanate); the molar ratio of polycaprolactone diol to diphenylmethane diisocyanate is 0.5:1, and the molar ratio of diphenylmethane diisocyanate to ethylene glycol is 1:0.3;

[0044] (2) Add capping agent 1,4-benzoquinone dioxime to the reaction system obtained in step (1), the molar ratio of the capping agent to diphenylmethane diisocyanate is 0.2:1, and react at 70 °C for 4 h under anhydrous conditions;

[0045] (3) Add COF material EB-COF:Br (the addition amount of the COF material is 5% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 8 h to obtain the self-healing polyurethane additive for perovskite batteries.

[0046] The infrared spectrum of the product obtained in step (1) of this example is asFigure 1 as shown, where a characteristic absorption peak of "-NCO" appears at 2100 - 2400 cm -1 ; an N-H absorption peak appears at 3300 - 3400 cm -1 ; a C=O stretching vibration absorption peak appears at 1700 - 1750 cm -1 ; and a strong absorption peak at 1000 - 1250 cm -1 is the C-O-C stretching vibration absorption peak.

[0047] The infrared spectrum of the product obtained in step (2) of this example is as Figure 2 shown, where the characteristic absorption peak of "-NCO" at 2100 - 2400 cm -1 still exists; however, the intensity of this peak becomes significantly weaker, which is the effect of capping with the capping agent.

[0048] Example 2

[0049] This example provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0050] (1) Polycaprolactone diol (molecular weight 2000, purchased from Daicel Chemical Industries, Ltd., Japan), chain extender diethylene glycol, and diphenylmethane diisocyanate react at 80 °C for 1 h under anhydrous conditions in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.5% of the mass of diphenylmethane diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of phenylmethane diisocyanate); the molar ratio of polycaprolactone diol to diphenylmethane diisocyanate is 0.6:1, and the molar ratio of diphenylmethane diisocyanate to diethylene glycol is 1:0.2;

[0051] (2) Add capping agent acetaldehyde oxime to the reaction system obtained in step (1), the molar ratio of the capping agent to diphenylmethane diisocyanate is 0.3:1, and react at 60 °C for 8 h under anhydrous conditions;

[0052] (3) Add COF material EB-COF:Br (the addition amount of the COF material is 8% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 6 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0053] Example 3

[0054] This example provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0055] (1) Polycarbonate diol (molecular weight 1000, purchased from Ube Industries, Japan), chain extender 1,4-butanediol, and isophthaloyl diisocyanate react in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.1% of the mass of isophthaloyl diisocyanate) and inhibitor BHT (the dosage is 0.2% of the mass of isophthaloyl diisocyanate) at 50 °C under anhydrous conditions for 8 h; the molar ratio of polycarbonate diol to isophthaloyl diisocyanate is 0.6:1, and the molar ratio of isophthaloyl diisocyanate to 1,4-butanediol is 1:0.2;

[0056] (2) Add capping agent cyclohexanone oxime to the reaction system obtained in step (1), the molar ratio of the capping agent to isophthaloyl diisocyanate is 0.1:1, and react at 80 °C for 2 h under anhydrous conditions;

[0057] (3) Add COF material EB-COF:Br (the addition amount of the COF material is 3% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 10 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0058] Example 4

[0059] This example provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0060] (1) Polyoxyethylene ether diol (molecular weight 1000, purchased from Dow Chemical) reacts with chain extender 1,4-cyclohexanedimethanol and isophorone diisocyanate in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.05% of the mass of isophorone diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of isophorone diisocyanate) at 70 °C under anhydrous conditions for 4 h; the molar ratio of polyoxyethylene ether diol to isophorone diisocyanate is 0.5:1, and the molar ratio of isophorone diisocyanate to 1,4-cyclohexanedimethanol is 1:0.4;

[0061] (2) Add capping agent 4-hydroxyacetophenone oxime to the reaction system obtained in step (1), the molar ratio of the capping agent to isophorone diisocyanate is 0.3:1, and react at 70 °C for 4 h under anhydrous conditions;

[0062] (3) Add COF material EB-COF:Br (the addition amount of the COF material is 9% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 7 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0063] Example 5

[0064] This embodiment provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0065] (1) Poly(tetramethylene ether) glycol (molecular weight 1000, purchased from South Korea's Hyosung), chain extender ethylene glycol, and diphenylmethane diisocyanate react in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.05% of the mass of diphenylmethane diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of diphenylmethane diisocyanate) at 70 °C under anhydrous conditions for 5 h; the molar ratio of poly(tetramethylene ether) glycol to diphenylmethane diisocyanate is 0.6:1, and the molar ratio of diphenylmethane diisocyanate to ethylene glycol is 1:0.3;

[0066] (2) Add capping agent acetaldoxime to the reaction system obtained in step (1), the molar ratio of the capping agent to diphenylmethane diisocyanate is 0.2:1, and react at 70 °C under anhydrous conditions for 3 h;

[0067] (3) Add COF material TpPa-SO3H (the addition amount of the COF material is 3% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 6 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0068] Example 6

[0069] This embodiment provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0070] (1) Polycaprolactone diol (molecular weight 1000, purchased from Japan's Daicel) and chain extender 1,6-hexanediol and dicyclohexylmethane diisocyanate react in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.8% of the mass of dicyclohexylmethane diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of dicyclohexylmethane diisocyanate) at 40 °C under anhydrous conditions for 10 h; the molar ratio of polycaprolactone diol to dicyclohexylmethane diisocyanate is 0.6:1, and the molar ratio of dicyclohexylmethane diisocyanate to 1,6-hexanediol is 1:0.4;

[0071] (2) Add capping agent 1,4-benzoquinone dioxime to the reaction system obtained in step (1), the molar ratio of the capping agent to dicyclohexylmethane diisocyanate is 0.3:1, and react at 60 °C under anhydrous conditions for 8 h;

[0072] (3) Add COF material TpPa-SO3H (the addition amount of the COF material is 9% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 60 °C for 10 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0073] Example 7

[0074] This example provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0075] (1) Polycarbonate diol (molecular weight 2000, purchased from Ube Industries, Japan), chain extender neopentyl glycol, and hexamethylene diisocyanate react in the presence of catalyst dibutyltin dilaurate (the addition amount of dibutyltin dilaurate is 0.8% of the mass of hexamethylene diisocyanate) and inhibitor BHT (the dosage is 0.05% of the mass of hexamethylene diisocyanate) at 60 °C under anhydrous conditions for 7 h; the molar ratio of polycarbonate diol to hexamethylene diisocyanate is 0.6:1, and the molar ratio of hexamethylene diisocyanate to neopentyl glycol is 1:0.2;

[0076] (2) Add capping agent cyclohexanone oxime to the reaction system obtained in step (1), the molar ratio of the capping agent to hexamethylene diisocyanate is 0.3:1, and react at 60 °C under anhydrous conditions for 8 h;

[0077] (3) Add COF material EB-COF:Br (the addition amount of the COF material is 5% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 65 °C for 7 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0078] Example 8

[0079] This example provides a self-healing polyurethane additive for perovskite solar cells, and its preparation method includes the following steps:

[0080] (1) Polyoxyethylene ether diol (molecular weight 1500, purchased from Dow Chemical), chain extender 1,3-propanediol, and isophorone diisocyanate react in the presence of catalyst bismuth laurate (the addition amount of bismuth laurate is 0.1% of the mass of isophorone diisocyanate) and inhibitor BHT (the dosage is 0.1% of the mass of isophorone diisocyanate) at 60 °C under anhydrous conditions for 7 h; the molar ratio of polyoxyethylene ether diol to isophorone diisocyanate is 0.6:1, and the molar ratio of isophorone diisocyanate to 1,3-propanediol is 1:0.3;

[0081] (2) Add the capping agent acetone oxime to the reaction system obtained in step (1). The molar ratio of the capping agent to 1,3-propanediol is 0.2:1. Under anhydrous conditions, react at 70 °C for 8 h;

[0082] (3) Add the COF material EB-COF:Br (the addition amount of the COF material is 8% of the total mass of the preparation raw materials) to the product obtained in step (2), and mix at 70 °C for 10 h to obtain the self-healing polyurethane additive for perovskite solar cells.

[0083] Comparative Example 1

[0084] The difference from Example 1 is only that the capping agent in step (2) is replaced with an equimolar amount of hexamethylenediamine.

[0085] Comparative Example 2

[0086] The difference from Example 1 is only that the chain extender ethylene glycol in step (1) is replaced with glycerol.

[0087] Comparative Example 3

[0088] The difference from Example 1 is only that step (3) is not carried out.

[0089] Add the polyurethane additives prepared in the examples and comparative examples to the purchased commercial perovskite precursor (lead iodide (PbI₂) from Ningbo Borun New Materials, model Pb101A) with an addition amount of 2 wt%, and prepare perovskite thin films by one-step spin coating method. Perform performance tests, and the test methods are as follows:

[0090] (1) Crack recovery test: Use mechanical methods to generate microcracks on the surface of the prepared perovskite thin film to simulate external damage. Irradiate the damaged thin film with ultraviolet light. Use a scanning electron microscope (SEM) to check the repair of the cracks every 24 h, and evaluate whether the cracks gradually close and reduce the crack size. Observe the initial state, observe the longest distance L₀ of the initial crack under the microscope, 24 h after ultraviolet light irradiation, the longest size L₁ of the crack, and 72 h after ultraviolet light irradiation, the longest size L₂ of the crack, and calculate:

[0091] Self-healing rate at 24 h = (L₀ - L₁) / L₀ × 100%

[0092] Self-healing rate at 72 h = (L₀ - L₂) / L₀ × 100%.

[0093] (2) Line resistance test

[0094] Print serpentine sheet conductive copper paste on the perovskite thin film, and after baking at 160 °C for 30 minutes to form, place it under ultraviolet light irradiation for 72 h, and then use a micro-ohmmeter to measure the resistance value at both ends of the serpentine copper paste. The test results are shown in Table 1.

[0095] Table 1

[0096]

[0097] As can be seen from the data in Table 1, the self-healing polyurethane of the present invention has good self-healing function and can avoid affecting the photoelectric conversion efficiency of perovskite batteries during the repair process.

[0098] It can be seen from Examples 1-8 that all have good self-healing effects, and at the same time the line resistance is reduced. In Comparative Example 1, due to the lack of an oxime material with self-healing effect, the repair effect is very poor. In Comparative Example 2, after adding trifunctional polyol, the material strength increases, the flexibility decreases, and the self-healing effect also decreases. In Comparative Example 3, due to the lack of addition of COF material, although the self-healing effect exists, the electrical performance decreases because the prepared material itself is an insulating material.

[0099] The applicant declares that the present invention uses the above-mentioned examples to illustrate the self-healing polyurethane additive for perovskite batteries of the present invention, its preparation method and application. However, the present invention is not limited to the above-mentioned examples, that is, it does not mean that the present invention must rely on the above-mentioned examples to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A self-healing polyurethane additive for perovskite batteries, characterized in that, The raw materials for preparing the self-healing polyurethane additive for perovskite batteries include diisocyanate, polyol, chain extender, capping agent, catalyst, inhibitor and COF material. The chain extender is a small molecule diol, and the capping agent is selected from any one or a combination of at least two of 1,4-benzoquinone dioxime, 4-hydroxyacetophenone oxime, acetaldehyde oxime, acetone oxime or cyclohexanone oxime.

2. The self-healing polyurethane additive for perovskite cells according to claim 1, characterized in that, The diisocyanate is one or a combination of at least two of diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate.

3. The self-healing polyurethane additive for perovskite cells according to claim 1 or 2, characterized in that, The polyol is one or a combination of at least two of polycaprolactone diol, polycarbonate diol, polyoxyethylene ether diol, polytetrahydrofuran ether diol; The number average molecular weight of the polyol is 1000 - 2000.

4. The self-healing polyurethane additive for perovskite cells according to any one of claims 1-3, characterized in that The chain extender is one or a combination of at least two of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or neopentyl glycol; Preferably, the catalyst is selected from dibutyltin dilaurate and / or bismuth laurate; Preferably, the inhibitor is selected from 2,6-di-tert-butyl-4-methylphenol or p-methoxyphenol; Preferably, the COF material is selected from EB-COF:Br and / or TpPa-SO3H.

5. The self-healing polyurethane additive for perovskite cells according to any one of claims 1-4, characterized in that The molar ratio of diisocyanate to polyol in the raw materials is 1:0.5 - 0.7; Preferably, the molar ratio of diisocyanate to chain extender in the raw materials is 1:0.2 - 0.4; Preferably, the molar ratio of diisocyanate to capping agent in the raw materials is 1:0.1 - 0.3; Preferably, the dosage of the catalyst in the raw materials is 0.05% - 1% of the mass of diisocyanate; Preferably, the dosage of the inhibitor in the raw materials is 0.05% - 0.2% of the mass of diisocyanate; Preferably, the COF material in the raw materials is 3 - 9% of the total mass of the raw materials.

6. The preparation method of the self-healing polyurethane additive for perovskite batteries according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) The polyol, the chain extender and the diisocyanate react in the presence of the catalyst and the inhibitor; (2) Add the capping agent to the reaction system obtained in step (1) and react; (3) Add the COF material to the product obtained in step (2) and mix to obtain the self-healing polyurethane additive for perovskite batteries.

7. The preparation method according to claim 6, characterized in that, The reaction in step (1) is carried out under anhydrous conditions; Preferably, the temperature of the reaction in step (1) is 40 - 80°C, and the reaction time is 1 - 10 h; Preferably, the temperature of the reaction in step (2) is 60 - 80°C, and the reaction time is 2 - 8 h; Preferably, the mixing in step (3) is carried out at a temperature of 60 - 70°C, and the mixing time is 6 - 10 h.

8. A perovskite precursor, characterized in that, The perovskite precursor includes the self-healing polyurethane additive for perovskite batteries according to any one of claims 1 - 5; Preferably, the addition amount of the self-healing polyurethane additive for perovskite batteries in the perovskite precursor is 1 - 5 wt%.

9. A perovskite thin film, characterized in that, The perovskite film is prepared from the perovskite precursor described in any one of claims 1-5.

10. A perovskite solar cell, characterized in that, The perovskite solar cell includes the perovskite film described in any one of claims 1-5.

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