A functional set fluid, its preparation method and application

Abstract

The present invention provides a functional current collector and its preparation method and application. The functional current collector sequentially includes a base film, a hybrid organic-inorganic perovskite coating, and a metal layer; the material of the hybrid organic-inorganic perovskite coating includes a two-dimensional hybrid organic-inorganic perovskite material; the two-dimensional hybrid organic-inorganic perovskite material includes at least one of a non-chiral two-dimensional hybrid organic-inorganic perovskite material, a mixed non-chiral two-dimensional hybrid organic-inorganic perovskite material, a semi-chiral two-dimensional hybrid organic-inorganic perovskite material, and a fully chiral two-dimensional hybrid organic-inorganic perovskite material. This functional current collector has a lower residual stress, effectively enhances the thermal stability and mechanical strength of the functional current collector, thereby optimizing the stability of the battery during the charge and discharge cycle process, and improving the battery cycle performance and thermal stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery current collectors, and particularly relates to a functional current collector, a preparation method thereof and an application thereof. Background Art

[0002] Residual stress is an important issue in thin film applications because it can limit the performance range or cause failure. The stress generated during the thin film deposition process is usually referred to as the intrinsic stress. However, stress can also be generated by effects that occur after deposition, such as the thermal expansion mismatch between the thin film and the substrate or grain growth in a thin film with sufficient atomic mobility. Different deposition methods where the deposited material has low energy (such as evaporation, electrodeposition) or high energy (such as sputtering deposition) will also result in very different stress states. Generally speaking, the adhesion of the coating on the substrate depends on some characteristics of the interface region, including the type of bond between the coating and the substrate, microstructure, and stress state. The total stress in the coating consists of thermal stress and intrinsic stress. The thermal stress is generated due to the inconsistency between the thermal expansion coefficient of the coating and that of the substrate. The intrinsic stress is generated during the growth of the coating and is caused by factors such as impurity incorporation and structural reordering. At the same time, the presence of surface tension during the winding and unwinding process will also cause changes in the film surface stress, thereby affecting the internal stress between the coating molecules.

[0003] During the coating process (vacuum coating / magnetron sputtering), the temperature in the sputtering chamber / evaporation chamber is relatively high, and common polymer-based films such as PET-based films will undergo plastic deformation at high temperatures, resulting in a tensile stress that persists in subsequent processes. Moreover, during the heat transfer process when the high-temperature evaporation gas contacts the low-temperature substrate film, thermal stress will be generated. At the same time, during the process of the gas depositing onto the substrate film, some of the gas molecules collide with each other, causing a decrease in the kinetic energy they carry, while some molecules with fewer collisions carry higher kinetic energy. When these molecules come into contact with the film, the released kinetic energy causes non-uniform internal stress between the coating and the substrate film.

[0004] In the preparation of functional current collectors, a coating is usually deposited on a polymer-based film. Therefore, the functional current collectors also have the above-mentioned tensile stress, thermal stress, and internal stress problems, resulting in a relatively large residual stress in the formed functional current collectors, which affects the performance of the functional current collectors such as thermal stability and mechanical strength. Summary of the Invention

[0005] To solve the problems and deficiencies existing in the prior art, the present invention provides a functional current collector and its preparation method and application. The functional current collector is formed by first coating a hybrid organic-inorganic perovskite coating on the surface of a polymer-based film. The material of this coating is a two-dimensional hybrid organic-inorganic perovskite material. Therefore, the formed coating has high hardness, high tensile strength, and good heat insulation effect. It can not only effectively block the influence of heat generated during processes such as evaporation / magnetron deposition plating on the thermal stress of the surface of the base film, but also reduce the deformation caused by the tensile force during the winding process of the film surface and lower the strain stress. As a result, the finally prepared functional current collector has lower residual stress, effectively enhancing the thermal stability and mechanical strength of the functional current collector, and further optimizing the stability of the battery during the charge and discharge cycle process, improving the battery cycle performance and thermal stability.

[0006] According to the first aspect of the present invention, there is provided a functional current collector, which sequentially includes a base film, a hybrid organic-inorganic perovskite coating, and a metal layer; the material of the hybrid organic-inorganic perovskite coating includes a two-dimensional hybrid organic-inorganic perovskite material; the two-dimensional hybrid organic-inorganic perovskite material includes at least one of a non-chiral two-dimensional hybrid organic-inorganic perovskite material, a mixed non-chiral two-dimensional hybrid organic-inorganic perovskite material, a semi-chiral two-dimensional hybrid organic-inorganic perovskite material, and a fully chiral two-dimensional hybrid organic-inorganic perovskite material.

[0007] Currently, the application of hybrid organic-inorganic perovskite materials is mainly in the field of solar cells, mainly utilizing their excellent optoelectronic properties. These properties include an adjustable optical bandgap, a high light absorption coefficient, a low exciton dissociation energy, etc. These properties have enabled perovskite materials to be widely studied for application in the photovoltaic field. Therefore, hybrid organic-inorganic perovskite materials are rarely applied in the field of lithium batteries, especially in the field of lithium battery current collectors.

[0008] At present, hybrid organic-inorganic perovskite materials are mainly composed of two-dimensional hybrid organic-inorganic perovskite materials and three-dimensional hybrid organic-inorganic perovskite materials. The main difference between two-dimensional hybrid organic-inorganic perovskite and three-dimensional hybrid organic-inorganic perovskite is their structural dimension and composition. Two-dimensional hybrid organic-inorganic perovskite adopts a layered structure in which organic cation layers and inorganic anion skeletons are loosely connected and alternate with each other. This structure provides a rich material platform, and through strategies such as molecular modification and molecular self-assembly, the design and regulation of relevant functional properties can be achieved. Three-dimensional hybrid organic-inorganic perovskite is composed of organic and inorganic components alternately combined in three-dimensional space, forming a continuous crystal structure. Moreover, because the organic and inorganic parts in the structure of three-dimensional hybrid organic-inorganic perovskite materials are connected by weak interactions, such as hydrogen bonds or van der Waals forces, their structural stability is poor when facing external environmental factors such as humidity and temperature changes, and they are prone to degradation or phase change. In contrast, two-dimensional hybrid organic-inorganic perovskite materials have higher structural stability, thanks to their special layered structure, in which the organic cation layers and the inorganic anion skeleton are loosely connected and alternate with each other, forming a relatively stable structure.

[0009] Therefore, the present invention selects a two-dimensional hybrid organic-inorganic perovskite material with better stability to form a hybrid organic-inorganic perovskite coating on a polymer base film, especially the non-chiral, mixed non-chiral, semi-chiral, and fully chiral two-dimensional hybrid organic-inorganic perovskite materials listed above, whose structures produce π-π and CH-π interactions on the organic-organic interface, which can effectively increase the interaction between structures while reducing the thermal conductivity. Therefore, firstly, the hybrid organic-inorganic perovskite coating formed by it can have high hardness and high tensile strength, and then the base film containing the hybrid organic-inorganic perovskite coating and the functional current collector finally obtained also have high hardness and high tensile strength, thereby effectively reducing the deformation caused by the tension in the film surface winding process in each step of preparing the functional current collector, and reducing the tensile residual stress. Secondly, the hybrid organic-inorganic perovskite coating formed by the method can have a low thermal conductivity and high density, which can play a good role in heat insulation for the polymer base film, so that in the process of continuing to deposit the oxide coating and metal layer by evaporation / magnetron, the influence of high temperature on the polymer base film can be reduced, and the stress caused by thermal deformation can be effectively reduced. Thirdly, because the surface of the polymer base film is coated with this layer of high hardness and high tensile strength hybrid organic-inorganic perovskite coating, the high energy bombardment caused by the process of continuing to deposit the oxide coating and metal layer by evaporation / magnetron can reduce the perforation of the polymer base film surface caused by the high energy bombardment caused by the process of continuing to deposit the oxide coating and metal layer by evaporation / magnetron, so as to further improve the structural strength of the functional current collector, optimize the stability of the functional current collector in the battery cycle, and then optimize the battery cycle performance and thermal stability.

[0010] It should be noted here that the differences between achiral, mixed achiral, semi-chiral, and fully chiral two-dimensional hybrid organic-inorganic perovskite materials are as follows: achiral refers to molecules that do not have chiral carbons and chiral centers; mixed achiral refers to molecules formed by the combination of two achiral molecules; semi-chiral refers to molecules formed by the combination of chiral and achiral molecules; fully chiral refers to molecules with exactly the same molecular structure but opposite left and right arrangements, such as an object and its mirror image.

[0011] Preferably, the thickness of the hybrid organic-inorganic perovskite coating is 130 - 170 nm. Controlling the thickness of the hybrid organic-inorganic perovskite coating within the above range can not only effectively insulate heat, improve hardness and tensile strength, effectively relieve thermal stress and tensile stress, reduce thermal deformation and tensile deformation, and reduce overall residual stress, but also effectively avoid the situation of perforation on the surface of the polymer-based film caused by high-energy bombardment during the deposition of other coatings, thereby effectively optimizing the mechanical strength and thermal stability of the functional current collector; moreover, it can also take into account that the overall functional current collector has a more appropriate thickness, avoiding the influence of the excessive thickness of the functional current collector on the energy density of the battery, and at the same time avoiding the influence of the excessive thickness of the hybrid organic-inorganic perovskite coating on the conductivity or other properties of the functional current collector itself.

[0012] Preferably, when the material of the hybrid organic-inorganic perovskite coating includes achiral two-dimensional hybrid organic-inorganic perovskite material, the thickness of the hybrid organic-inorganic perovskite coating is 145 - 155 nm; when the material of the hybrid organic-inorganic perovskite coating includes mixed achiral two-dimensional hybrid organic-inorganic perovskite material, the thickness of the hybrid organic-inorganic perovskite coating is 155 - 165 nm; when the material of the hybrid organic-inorganic perovskite coating includes semi-chiral two-dimensional hybrid organic-inorganic perovskite material, the thickness of the hybrid organic-inorganic perovskite coating is 135 - 145 nm; when the material of the hybrid organic-inorganic perovskite coating includes chiral two-dimensional hybrid organic-inorganic perovskite material, the thickness of the hybrid organic-inorganic perovskite coating is 148 - 158 nm. When the materials of the hybrid organic-inorganic perovskite coating are achiral, mixed achiral, semi-chiral, and fully chiral two-dimensional hybrid organic-inorganic perovskite materials respectively, controlling the thickness of the formed hybrid organic-inorganic perovskite coating within the above ranges is more conducive to relieving thermal stress and tensile stress during the preparation of the functional current collector, making the comprehensive stability of the functional current collector higher while effectively insulating heat, and further taking into account various performance aspects such as the cycle performance, safety performance, and energy density of the battery.

[0013] Preferably, the achiral two-dimensional hybrid organic-inorganic perovskite material includes [C4A]2PbI4; the mixed achiral two-dimensional hybrid organic-inorganic perovskite material includes [C4A]2[PEA]PbI4; the semi-chiral two-dimensional hybrid organic-inorganic perovskite material includes [SMePEA]2[C3A]PbI4; the chiral two-dimensional hybrid organic-inorganic perovskite material includes [SMePEA]2PbI4; wherein, in [C4A]2PbI4, [C4A]2[PEA]PbI4, [SMePEA][C3A]PbI4 and [SMePEA]2PbI4, C4A is C4NH3 + , PEA is , S indicates that the structure is left-handed chiral, Me is methyl, and SMePEA is , C3A is . Among the above several specific two-dimensional hybrid organic-inorganic perovskite materials, in practical applications, the formed hybrid organic-inorganic perovskite coating can effectively reduce thermal stress and tensile stress, that is, effectively reduce the residual stress in the preparation process of the functional current collector, optimize the mechanical strength and thermal stability of the functional current collector, and optimize the battery performance.

[0014] Preferably, when the material of the hybrid organic-inorganic perovskite coating includes at least one of the achiral two-dimensional hybrid organic-inorganic perovskite material and the mixed achiral two-dimensional hybrid organic-inorganic perovskite material. Compared with the semi-chiral and chiral two-dimensional hybrid organic-inorganic perovskite materials, the achiral and mixed achiral two-dimensional hybrid organic-inorganic perovskite materials usually have a lower alkyl carbon chain length, so the thermal conductivity is lower and the hardness is higher. Just like the achiral, mixed achiral, semi-chiral, and fully chiral two-dimensional hybrid organic-inorganic perovskite materials, during the change process from the achiral to the chiral two-dimensional hybrid organic-inorganic perovskite material, the thermal conductivity will increase and the hardness will decrease. Therefore, the hybrid organic-inorganic perovskite coating formed by the achiral and mixed achiral two-dimensional hybrid organic-inorganic perovskite materials has better heat insulation performance, higher hardness and tensile strength, can more significantly reduce the thermal stress and tensile stress in the preparation process of the functional current collector, that is, more significantly reduce the residual stress, and is more conducive to the improvement of the mechanical strength and thermal stability of the functional current collector.

[0015] It should also be noted here that in these two-dimensional hybrid organic-inorganic perovskite materials, as the alkyl carbon chain length of the organic part increases, both the thermal conductivity and the hardness will decrease. Therefore, it is also necessary to appropriately control the alkyl carbon chain length of the organic part so that the coating formed by the two-dimensional hybrid organic-inorganic perovskite material has good heat insulation performance, hardness and tensile properties.

[0016] Preferably, the thickness of the base film is 6-8 μm; the thickness of the metal layer is 0.8-1.2 μm. Controlling the thicknesses of the base film and the metal layer within the above ranges can endow the functional current collector with good mechanical properties and electrical conductivity, etc., without causing a decrease in the battery energy density due to the excessive thickness of the functional current collector.

[0017] Preferably, the above functional current collector sequentially includes a base film, a hybrid organic-inorganic perovskite coating, an oxide coating, and a metal layer. An oxide coating is provided between the hybrid organic-inorganic perovskite coating and the metal layer. In the functional current collector, the main function of depositing the oxide layer of the ceramic layer before depositing the metal layer is to improve the mechanical properties of the functional current collector, meet the preparation process requirements of the battery electrode coating and rolling processes, and thus improve the overall performance and reliability of the battery.

[0018] Preferably, the thickness of the oxide coating is 0.5-20 nm. Similarly, the thickness of the oxide coating also needs to be within a certain numerical range, so as to balance the mechanical properties, electrical conductivity of the functional current collector and the energy density of the battery.

[0019] Preferably, the material of the base film includes at least one of polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polystyrene, and polyimide;

[0020] Preferably, the material of the oxide coating includes at least one of alumina and silica. Preferably, the material of the oxide coating includes alumina.

[0021] Preferably, the material in the metal layer includes at least one of aluminum and copper. Preferably, the material of the metal layer includes aluminum.

[0022] According to the second aspect of the present invention, there is provided a method for preparing the above functional current collector, including the following steps: S1. Prepare a hybrid organic-inorganic perovskite mixture, coat the mixture on the surface of the base film, and dry it to form a hybrid organic-inorganic perovskite coating on the surface of the base film; S2. Continuously deposit an oxide coating on the surface of the hybrid organic-inorganic perovskite coating; the deposition method includes at least one of magnetron sputtering and vacuum coating; S3. Continuously deposit a metal layer on the surface of the oxide coating; the deposition method includes at least one of magnetron sputtering and vacuum coating. The functional current collector prepared by the above steps has uniform and dense coatings for each layer and strong mutual compactness, reducing the residual stress in the preparation process of the functional current collector and optimizing its mechanical strength and thermal stability.

[0023] Preferably, in S1, during the preparation of the hybrid organic-inorganic perovskite mixture, the mass ratio of the hybrid organic-inorganic perovskite powder to the solvent is 2-4:1; the solvent includes water and acetone, and the volume ratio of water to acetone is 1-2:1.

[0024] In summary, by introducing a layer of hybrid organic-inorganic perovskite coating on the surface of the polymer-based film, the coating has high hardness, high tensile strength and good heat insulation effect. It can not only effectively block the influence of heat generated during processes such as evaporation / magnetron sputtering coating on the thermal stress of the film surface, but also reduce the deformation caused by the tensile force during the winding process of the film surface and lower the strain stress. Therefore, the overall residual stress of the functional current collector is effectively reduced, the mechanical properties and thermal stability of the functional current collector are improved, and the purpose of optimizing the battery cycle performance and thermal stability is achieved. Detailed implementation manners

[0025] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0026] Embodiment 1

[0027] The functional current collector of this embodiment is prepared according to the following steps:

[0028] S1. Place the achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2PbI4 (C4A is C4NH3 + ) in a water / acetone mixture (water / acetone volume ratio = 1.5:1), the mass ratio of [C4A]2PbI4 to the water / acetone mixture is 3:1, and ultrasonically treat for 30 min to make the solid-liquid mixture uniform; coat the obtained mixture evenly on both sides of the PET (polyethylene terephthalate) base film and dry it at 80 °C for 20 min to form a hybrid organic-inorganic perovskite coating on both sides of the base film; wherein the thickness of the PET base film is 7 μm, and the thickness of the hybrid organic-inorganic perovskite coating is 150 nm;

[0029] S2. Then, an alumina coating and an aluminum layer are sequentially deposited on the surfaces of the two hybrid organic-inorganic perovskite coatings. The specific operations are as follows: Fix the film product obtained in S1 to the winding trolley, perform threading for winding and unwinding, and then adjust the tension. The unwinding end is 120 N and the winding end is 100 N. After the winding trolley enters the evaporation chamber, evacuate to 5×10 -3 Pa, start the winding trolley, control the speed at 280-300 m / min, heat the evaporation boat and feed the aluminum wire at the same time, the wire feeding speed is 300-350 mm / min, and at the same time start the oxygen intake to perform alumina underlay on the base film surface, and control the vacuum degree at 5×10-2 Pa; Then, vacuum is broken and an aluminum layer is deposited in the same manner, with a heating temperature of 1000 - 1200 °C; In this step, the deposition time during coating is controlled so that the thickness of the aluminum oxide layer on each side is 5 nm and the thickness of the aluminum layer is 1 μm.

[0030] Example 2

[0031] In the process of preparing the functional current collector in this example, different from Example 1, the achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2PbI4 is replaced with the mixed achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2[PEA]PbI4 (where C4A is C4NH3 + , and PEA is ). The remaining operations are the same as those in Example 1.

[0032] Example 3

[0033] In the process of preparing the functional current collector in this example, different from Example 1, the achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2PbI4 is replaced with the semi-chiral two-dimensional hybrid organic-inorganic perovskite material [SMePEA]2[C3A]PbI4 (where SMePEA is , and C3A is ). The remaining operations are the same as those in Example 1.

[0034] Example 4

[0035] In the process of preparing the functional current collector in this example, different from Example 1, the achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2PbI4 is replaced with the chiral two-dimensional hybrid organic-inorganic perovskite material [SMePEA]2PbI4 (where SMePEA is ). The remaining operations are the same as those in Example 1.

[0036] Example 5

[0037] In the process of preparing the functional current collector in this example, different from Example 1, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled so that the thickness of the hybrid organic-inorganic perovskite coating is 140 nm. The rest is the same as that in Example 1.

[0038] Example 6

[0039] In the process of preparing the functional current collector in this example, different from Example 2, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled so that the thickness of the hybrid organic-inorganic perovskite coating is 170 nm. The rest is the same as that in Example 2.

[0040] Example 7

[0041] In the process of preparing the functional current collector in this embodiment, different from Example 3, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled to be 130 nm. The rest is the same as in Example 3.

[0042] Example 8

[0043] In the process of preparing the functional current collector in this embodiment, different from Example 4, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled to be 165 nm. The rest is the same as in Example 4.

[0044] Example 9

[0045] In the process of preparing the functional current collector in this embodiment, different from Example 3, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled to be 125 nm. The rest is the same as in Example 3.

[0046] Example 10

[0047] In the process of preparing the functional current collector in this embodiment, different from Example 2, in S1, the coating thickness of the hybrid organic-inorganic perovskite coating is controlled to be 175 nm. The rest is the same as in Example 2.

[0048] Example 11

[0049] In the process of preparing the functional current collector in this embodiment, different from Example 1, in S2, the coating thickness of the alumina coating is controlled to be 25 nm. The rest is the same as in Example 1.

[0050] Example 12

[0051] In the process of preparing the functional current collector in this embodiment, different from Example 1, in S2, the coating thickness of the metal layer is controlled to be 0.6 μm. The rest is the same as in Example 1.

[0052] Example 13

[0053] In the process of preparing the functional current collector in this embodiment, different from Example 1, in S2, the oxide coating and the metal layer are controlled to be a silicon oxide coating and a copper layer respectively. The specific operation is as follows: Then, an oxide coating and a copper layer are respectively deposited on the surfaces of the two hybrid organic-inorganic perovskite coatings. The specific process conditions are as follows: (1) Set the target arrangement method to 4 silicon oxide targets and 16 copper targets (purity is 99.95% for both), and the magnetron sputtering power density is 50 W / cm2 , the vacuum degree is 5×10 - 4 Pa, the protective gas is argon, and the flow rate is 50 mL / min; (2) Set a voltage for the target, with a magnitude of 200 V, start winding, with a speed of 25 m / min. The innermost layer is a brittle layer (silicon oxide layer), and the outermost layer is a copper layer; Control the deposition time so that the thickness of the metal layer is 20 nm and the thickness of the brittle layer (silicon oxide) is 5 nm; (3) Continuously perform electroless plating on the product obtained in (2). First, perform pre-plating, with a current magnitude of 0.5 - 1 A, and then increase the current in each plating bath for thickening plating, with a current magnitude of 1.2 - 3.5 A; The main component of the selected plating solution is copper sulfate, and the winding speed is 10 m / min; Make the thickness of the silicon oxide layer on each side be 5 nm and the thickness of the copper layer be 1 μm. The rest is the same as in Example 1.

[0054] Comparative Example 1

[0055] In the process of preparing the functional current collector in this comparative example, the difference from Example 1 is that the step of S1 is not carried out, that is, the hybrid organic-inorganic perovskite coating is not coated on the PET base film, but the alumina layer and the aluminum layer are directly deposited on the PET base film, and the S2 step is directly carried out by omitting the S1 step. The rest of the operations are the same as in Example 1.

[0056] Comparative Example 2

[0057] In the process of preparing the functional current collector in this example, the difference from Example 1 is that the achiral two-dimensional hybrid organic-inorganic perovskite material [C4A]2PbI4 is replaced with the chiral three-dimensional hybrid organic-inorganic perovskite material [SMBA]2PbI4 (SMBA is . The rest of the operations are the same as in Example 1.

[0058] Test Example

[0059] 1. Experimental construction method

[0060] Test the functional current collectors prepared in the above examples and comparative examples for thermal deformation, tensile deformation, tensile properties, surface pinholes, residual stress and other related properties.

[0061] (1) Thermal deformation test

[0062] Take samples of the functional current collector, with each sample size being 5×10 cm. Place them at different temperatures for 30 min, and then use a caliper to measure the length change in the MD (longitudinal) direction. By comparing with the length before the experiment, calculate the thermal elongation rate. The formula is: Thermal elongation rate = (L1 形变后 - L1 形变前 ) / L1 形变前 .

[0063] (2)Tensile Deformation Test

[0064] Samples of the functional fluid are taken, each with a size of 5*10 cm. Under normal temperature environment, they are placed for 30 minutes under different tensile forces (simulating the surface tension at the site in geometric progression. For example, during the production process, the width of the film surface is 1650 mm, and the tensile force is about 130 N. Corresponding to a 50 mm wide sample, the tensile force is about 4 N). Then, a caliper is used to measure the length change in the MD (longitudinal) direction. By comparing with the length before the experiment, the tensile elongation rate is calculated. The formula is: Tensile elongation rate = (L2 形变后 -L2 形变前 ) / L2 形变前 .

[0065] (3)Tensile Property Test

[0066] The room temperature tensile strength of the functional fluid is tested using an electronic universal material testing machine. The test conditions are a gauge length of 10 mm, a tensile speed of 100 mm / min, and a width of 15 mm. Other requirements are determined according to the method specified in GB / T 1040.3 - 2006.

[0067] (4)Surface Pinhole Test

[0068] The number of surface pinholes of the functional fluid is tested using a CCD machine. Through the backlight imaging method, a CCD linear array camera installed on the production line is used for real - time synchronous scanning, so as to capture the light leakage points and calculate the number of holes.

[0069] (5)Residual Stress Test

[0070] The residual stress of the functional fluid is measured by an X - ray residual stress tester of the μ - 360s model from QUANTUM Quantum Science Instruments Trading (Beijing) Co., Ltd. The specific operation is as follows: The cut sample is placed in the test chamber, and the sample is irradiated with X - rays. After a single - angle single incidence, a complete Debye ring is obtained using a two - dimensional detector. By comparing the difference between the Debye ring without stress and the deformed Debye ring in the stressed state, the change in the crystal plane spacing under stress and the corresponding stress are calculated. After applying stress, by analyzing the change in the Debye ring before and after a single incidence, the residual stress data can be obtained through the residual stress analysis software.

[0071] 2. Experimental Results

[0072] The test results of the thermal deformation, tensile deformation, tensile properties, surface pinholes, residual stress and other related properties of the functional fluids prepared in the above - mentioned examples and comparative examples are shown in Tables 1, 2, and 3.

[0073] Table 1 Thermal deformation data of the functional fluid in the examples and comparative examples (without additional tensile force)

[0074]

[0075] Table 2 Tensile deformation data of the functional set fluid in the examples and comparative examples

[0076]

[0077] Table 3 Tensile strength and surface pinhole data of the functional set fluid in the examples and comparative examples

[0078]

[0079] As can be seen from Tables 1-3 above, for the functional set fluid provided by the present invention, by first coating a hybrid organic-inorganic perovskite coating on the surface of the polymer-based film, this coating has high hardness, high tensile strength and good heat insulation effect, so that the finally obtained functional set fluid also has high hardness and high tensile strength. Thereby, it can effectively reduce the deformation caused by the tensile force during the film surface winding process in each step of preparing the functional set fluid, and reduce the tensile residual stress. At the same time, the number of holes caused by aluminum sputtering during the production process is reduced. Through the residual stress test on the film surface before and after improvement, the results show a high degree of improvement, greatly reducing the residual stress of the film surface. For details, reference can be made to Examples 1-13.

[0080] In Comparative Example 1, instead of coating a hybrid organic-inorganic perovskite coating on the PET-based film, an aluminum oxide layer and an aluminum layer are directly deposited on the PET-based film. Therefore, it is impossible to improve the hardness, tensile strength and heat insulation effect of the functional set fluid, nor can it effectively relieve the residual stress during the preparation process of the functional set fluid. Eventually, the functional set fluid starts to show thermal deformation at 180 °C, tensile deformation occurs under a tensile force of 5 N, the tensile strength is also significantly reduced, and the number of surface pinholes is significantly increased and the residual stress is significantly increased.

[0081] In Comparative Example 2, a three-dimensional hybrid organic-inorganic perovskite material is used. Compared with the two-dimensional hybrid organic-inorganic perovskite material, the three-dimensional hybrid organic-inorganic perovskite material has poor structural stability and is prone to degradation or phase change. Therefore, the finally obtained functional set fluid shows thermal deformation at 200 °C, tensile deformation occurs at 6 N, and the tensile strength of the functional set fluid is significantly reduced, and the number of surface pinholes and the residual stress are also relatively large.

[0082] Further observing Example 1 and Examples 2 to 4, when replaced with other two-dimensional hybrid organic-inorganic perovskite materials, the performance of the functional current collector in all aspects is also good. Moreover, when using non-chiral two-dimensional hybrid organic-inorganic perovskite materials, mixed non-chiral two-dimensional hybrid organic-inorganic perovskite materials, semi-chiral two-dimensional hybrid organic-inorganic perovskite materials, and chiral two-dimensional hybrid organic-inorganic perovskite materials, the related performance of the functional current collector decreases from high to low. That is, using non-chiral two-dimensional hybrid organic-inorganic perovskite materials is more conducive to improving the multi-faceted performance of the functional current collector and optimizing the comprehensive performance of the functional current collector.

[0083] Comparing Example 1 and Example 5, Example 2 and Example 6, Example 3 and Example 7, Example 4 and Example 8, it can be found that when using two-dimensional hybrid organic-inorganic perovskite materials of different chiral types, the thickness of the formed coating is limited within a certain range, which is more conducive to making the performance of the coating better, and making the multi-faceted performance of the final functional current collector perform more excellently.

[0084] Comparing Example 3 and Example 9, Example 2 and Example 10, the hybrid organic-inorganic perovskite coating is not within the range of 130 - 170 nm, resulting in a decline in all aspects of the performance of the hybrid organic-inorganic perovskite coating. This is because the hybrid organic-inorganic perovskite coating is part of the functional current collector and jointly constitutes the overall functional current collector with other coatings and the base film. An overly thin or overly thick hybrid organic-inorganic perovskite coating will affect the performance of other coatings or its own performance, and thus affect the overall performance of the final functional current collector.

[0085] Comparing Example 1 and Examples 11 and 12, when the thickness of the oxide coating or the metal layer is not within a specific numerical range (the thickness of the oxide coating in Example 11 is not within the range of 50 - 200 nm, and the thickness of the metal layer in Example 12 is not within the range of 0.8 - 1.2 μm), it will also affect the performance of the functional current collector. This shows that when each layer in the functional current collector is within a certain range, it is more conducive to the performance of the overall functional current collector, that is, more conducive to the comprehensive performance of the functional current collector.

[0086] Comparing Example 1 and Example 13, when the oxide coating and the metal layer are replaced with other materials, the finally prepared functional current collector also has good performance in all aspects.

[0087] The above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the above examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. A functional current collector, characterized in that: It includes a base film, a hybrid organic-inorganic perovskite coating, an oxide coating, and a metal layer in sequence; The material of the hybrid organic-inorganic perovskite coating includes a two-dimensional hybrid organic-inorganic perovskite material; The two-dimensional hybrid organic-inorganic perovskite material includes at least one of an achiral two-dimensional hybrid organic-inorganic perovskite material, a mixed achiral two-dimensional hybrid organic-inorganic perovskite material, a semi-chiral two-dimensional hybrid organic-inorganic perovskite material, and a fully chiral two-dimensional hybrid organic-inorganic perovskite material; the achiral two-dimensional hybrid organic-inorganic perovskite material includes [C4A]2PbI4; The mixed achiral two-dimensional hybrid organic-inorganic perovskite material includes [C4A]2[PEA]PbI4; The semi-chiral two-dimensional hybrid organic-inorganic perovskite material includes [SMePEA][C3A]PbI4; The chiral two-dimensional hybrid organic-inorganic perovskite material includes [SMePEA]2PbI4; Among them, in [C4A]2PbI4, [C4A]2[PEA]PbI4, [SMePEA][C3A]PbI4 and [SMePEA]2PbI4, C4A is C4NH3 + , PEA is , S indicates that the structure is left-handed, Me is methyl, SMePEA is , C3A is .

2. The functional fluid collector according to claim 1, characterized in that: The thickness of the hybrid organic-inorganic perovskite coating is 130-170 nm.

3. The functional fluid collector according to claim 2, characterized in that: The material of the hybrid organic-inorganic perovskite coating is the non-chiral two-dimensional hybrid organic-inorganic perovskite material, and the thickness of the hybrid organic-inorganic perovskite coating is 145-155 nm.

4. The functional fluid collector according to claim 2, characterized in that: The material of the hybrid organic-inorganic perovskite coating is the mixed non-chiral two-dimensional hybrid organic-inorganic perovskite material, and the thickness of the hybrid organic-inorganic perovskite coating is 155-165 nm.

5. The functional fluid collector according to claim 2, characterized in that: The material of the hybrid organic-inorganic perovskite coating is the semi-chiral two-dimensional hybrid organic-inorganic perovskite material, and the thickness of the hybrid organic-inorganic perovskite coating is 135-145 nm.

6. The functional fluid collector according to claim 2, characterized in that: The material of the hybrid organic-inorganic perovskite coating is the chiral two-dimensional hybrid organic-inorganic perovskite material, and the thickness of the hybrid organic-inorganic perovskite coating is 148-158 nm.

7. The functional fluid collector according to claim 1, characterized in that: The thickness of the base film is 6-8 μm; the thickness of the metal layer is 0.8-1.2 μm.

8. The functional current collector according to claim 1, characterized in that: The thickness of the oxide coating is 0.5-20 nm.

9. The functional current collector according to claim 1, characterized in that: The material of the base film includes at least one of polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene, and polyimide; The material of the oxide coating includes at least one of aluminum oxide and silicon oxide; The material in the metal layer includes at least one of aluminum, copper, manganese, lithium and zinc.

10. The method for preparing a functional current collector according to claim 1, characterized in that: The steps include: S1. preparing a hybrid organic-inorganic perovskite mixture, applying the mixture to the surface of the base film, and drying to form the hybrid organic-inorganic perovskite coating on the surface of the base film; S2. Continuing to deposit the oxide coating on the surface of the hybrid organic-inorganic perovskite coating; the deposition method includes at least one of magnetron sputtering and vacuum coating; S3. Continue to deposit the metal layer on the surface of the oxide coating; the deposition method includes at least one of magnetron sputtering and vacuum coating.

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