Metal organic framework coated aluminum foil current collector and preparation method thereof

Abstract

The invention discloses a metal organic framework coated aluminum foil current collector and a preparation method thereof, and relates to the technical field of sodium ion battery current collector materials. The HKUST-1 functional coating containing the hierarchical porous metal organic framework structure is coated on the surface of the double-sided light aluminum foil, and the porous structure of the metal organic framework material MOF allows ions to be uniformly distributed in the material, so that a rapid ion transmission path is provided; the three-dimensional porous network constructed on the surface of the aluminum foil provides electron conduction and ion diffusion channels, so that the sodium ion charging and discharging efficiency and the ion conductivity are improved, and the electrochemical performance of the battery is improved. The aluminum foil current collector has the characteristics of improving the sodium ion migration rate and the ion conductivity, so that the sodium ion battery has relatively good rate capability and circularity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sodium ion battery current collector material, in particular to a metal organic framework coated aluminum foil current collector and a preparation method thereof. BACKGROUND

[0002] In a secondary battery, a current collector is needed as a part of current convergence, and the material thereof is generally aluminum foil or copper foil; with the rapid development of sodium battery technology, the development of sodium ion battery with higher energy density is imperative. The sodium ion battery with higher energy density requires higher ion transmission rate, and the aluminum foil as the current collector plays a key role in collecting and conducting current in the battery (such as sodium ion battery), and its characteristics directly affect the ion migration rate and overall conductivity of the battery. The conductivity of the aluminum foil current collector is mainly affected by the conductivity of the material itself, the surface state and the coating material; and the ion migration rate is related to the surface morphology of the current collector, the coating structure and the interface impedance. Optimizing these factors can improve the battery performance. Therefore, there is an urgent need for a coated aluminum foil with low interface resistance and ion conductivity to improve the rate performance and cycle stability of the battery. SUMMARY

[0003] One of the purposes of the present application is to provide a metal organic framework coated aluminum foil current collector to solve the problems of poor rate performance and cycle stability of sodium ion battery. The second purpose of the present application is to provide a preparation method of the metal organic framework coated aluminum foil current collector to prepare the metal organic framework coated aluminum foil current collector.

[0004] The purposes of the present application can be achieved by the following technical solutions: In a first aspect, a metal organic framework coated aluminum foil current collector comprises a substrate and a coating layer coated on the substrate, the substrate is aluminum foil, and the coating layer is porous HKUST-1. The thickness of the substrate is 10-15 μm, and the thickness of the coating layer is 1-5 μm.

[0005] As a further scheme of the present application, the alloy grade of the aluminum foil is 1060, 1070 or 1235.

[0006] As a further scheme of the present application, the preparation method of the porous HKUST-1 comprises the following steps: S1. Dissolve copper salt and trimesic acid (H3BTC) in N,N-dimethylformamide (DMF), add anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixed solution; S2. Transfer the mixed solution to a reaction kettle, and crystallize under microwave assistance to obtain a deep blue mixture, which is centrifuged, washed and vacuum dried to obtain the porous HKUST-1.

[0007] Further, in S1, the copper salt is any one or more of copper chloride, copper sulfate, copper nitrate, copper bromide or copper acetate in any proportion.

[0008] Further, in S1, the volume ratio of anhydrous ethanol to N,N-dimethylformamide is 2-8:10.

[0009] Further, in the mixed solution, the molar concentration of trimesic acid is 0.08-0.5 mol / L, and the molar ratio of copper salt to trimesic acid is 1: (1-5).

[0010] Further, in S2, the process conditions of microwave-assisted crystallization are as follows: set the temperature rising program to rise at a rate of 1-3 ℃ / min to 65-85 ℃, then keep the temperature for 2-5 h, and then rise at a rate of 4-6 ℃ to 100-160 ℃ and keep the temperature for 8-22 h, and the power is 200-400 W.

[0011] Further, in S2, the vacuum drying temperature is 50-90 ℃, and the vacuum drying time is 10-12 h.

[0012] The second aspect is a preparation method of a metal organic framework coated aluminum foil current collector, comprising the following steps: Step 1: configure a coating slurry; Dissolve PVDF-HFP (polyvinylidene fluoride-co-hexafluoropropylene) in NMP (N-methyl-2-pyrrolidone) to obtain a PVDF-HFP / NMP solution, add porous HKUST-1 to the solution, stir and mix uniformly to obtain a coating slurry; Step 2: coating and drying; Uniformly coat the coating slurry on the aluminum foil, and dry to obtain a metal organic framework coated aluminum foil current collector.

[0013] As a further scheme of the application, in step 1, the mass concentration of the PVDF-HFP / NMP solution is 5%-10%.

[0014] As a further scheme of the application, in step 1, the mass ratio of porous HKUST-1 to PVDF-HFP / NMP solution is (1-3):(0.5-2).

[0015] As a further scheme of the application, in step 2, the drying temperature is 50-90 ℃.

[0016] Compared with the prior art, the application has the following advantages: 1. The metal organic framework coated aluminum foil current collector provided by the application is coated with a HKUST-1 functional coating layer containing a multi-level pore metal organic framework structure on the surface of a double-sided light aluminum foil, the porous structure of the metal organic framework material MOF allows ions to be uniformly distributed inside the material, provides a fast ion transmission path, the three-dimensional porous network constructed on the surface of the aluminum foil provides an electron conduction and ion diffusion channel, thereby improving the sodium ion charge and discharge efficiency and ion conductivity, and improving the electrochemical performance of the battery. The aluminum foil current collector has the characteristics of improving the sodium ion migration rate and ion conductivity, thereby making the sodium ion battery have good rate capability and cycle performance.

[0017] 2. The preparation method of the metal organic framework coated aluminum foil current collector provided by the application, in the preparation process, a microwave reaction kettle is used for crystallization, the non-contact heating characteristics of microwave radiation help to realize uniform heating of the reaction system, thereby improving the quality and crystallinity of the product; microwave heating can complete the synthesis reaction at a lower temperature and in a shorter time, compared with the traditional hydrothermal method or the solvent thermal method, microwave-assisted synthesis is more efficient and energy-saving, the microwave-assisted synthesis product can be more easily separated from the reaction system, and there is almost no by-product, thereby simplifying the processing steps. DETAILED DESCRIPTION

[0018] The specific embodiments of the application are described in detail below, but it should be understood that the scope of protection of the application is not limited by the specific embodiments.

[0019] The terms used in the embodiments of the application are only for the purpose of describing specific embodiments, and are not intended to limit the application. The singular forms "a", "said" and "the" used in the embodiments of the application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0020] It should be understood that in various embodiments of the application, the size of the serial number of each process does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0021] The weight of the related components mentioned in the specification of the embodiments of the application can not only refer to the specific content of each component, but also represent the weight ratio relationship between each component, therefore, as long as the content of the related components in the specification of the embodiments of the application is enlarged or reduced in proportion, it is within the scope disclosed in the specification of the embodiments of the application. Specifically, the mass mentioned in the specification of the embodiments of the application can be μg, mg, g, kg and other mass units commonly known in the chemical field.

[0022] Unless otherwise defined, all terms used in the present application, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in the present application should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the technical field of the application, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0023] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by existing methods. In the following examples or comparative examples, the base aluminum foil is a conventional double-sided bright aluminum foil for lithium-ion batteries, alloy grade 1070, thickness 12 μm.

[0024] The present application will be further described in conjunction with specific examples.

[0025] Preparation Example 1

[0026] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Dissolve copper salt (2.5 mmol of copper chloride) and trimesic acid (2.5 mmol) in 15 mL of N,N-dimethylformamide, add 5 mL of anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixture; S2. Transfer the mixture to a microwave reaction kettle, set the temperature program to heat at a rate of 2℃ / min to 75℃, then keep the temperature for 4h, and then heat at a rate of 5℃ to 120℃ for 20h, with a power of 300W; microwave-assisted crystallization to obtain a dark blue mixture; after the reaction kettle is cooled to room temperature (25-30℃), centrifugation is performed, and the obtained dark blue substance is washed with N,N-dimethylformamide and anhydrous ethanol for 3 times respectively, and then transferred to a 90℃ vacuum drying oven for vacuum drying for 12h to obtain porous HKUST-1.

[0027] Preparation Example 2

[0028] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Dissolve copper salt (2.5 mmol of copper chloride) and trimesic acid (2.5 mmol) in 15 mL of N,N-dimethylformamide, add 5 mL of anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixture; S2. Transfer the mixture to a microwave reaction kettle, set the temperature program to heat at a rate of 2℃ / min to 75℃, then keep the temperature for 4h, and then heat at a rate of 5℃ to 120℃ for 20h, with a power of 300W; microwave-assisted crystallization to obtain a dark blue mixture; after the reaction kettle is cooled to room temperature (25-30℃), centrifugation is performed, and the obtained dark blue substance is washed with N,N-dimethylformamide and anhydrous ethanol for 3 times respectively, and then transferred to a 90℃ vacuum drying oven for vacuum drying for 12h to obtain porous HKUST-1.

[0029] Preparation Example 3

[0030] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Dissolve copper salt (15 mmol of copper nitrate) and trimesic acid (30 mmol) in 100 mL of N,N-dimethylformamide, add 30 mL of anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixture; S2. Transfer the mixture to a microwave reaction kettle, set the temperature program to increase the temperature to 75°C at a rate of 1°C / min, and then keep the temperature for 5 h, and then increase the temperature to 130°C at a rate of 6°C, and keep the temperature for 10 h, and the power is 300 W; microwave-assisted crystallization to obtain a dark blue mixture; after the reaction kettle is cooled to room temperature, centrifugation is performed, and the obtained dark blue substance is washed with N,N-dimethylformamide and anhydrous ethanol for 3 times respectively, and then transferred to a 90°C vacuum drying box for vacuum drying for 6 h to obtain porous HKUST-1.

[0031] Preparation Example 4

[0032] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Dissolve copper salt (20 mmol of copper chloride) and trimesic acid (30 mmol) in 150 mL of N,N-dimethylformamide, add 50 mL of anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixture; S2. Transfer the mixture to a microwave reaction kettle, set the temperature program to increase the temperature to 75°C at a rate of 2°C / min, and then keep the temperature for 2 h, and then increase the temperature to 160°C at a rate of 5°C, and keep the temperature for 8 h, and the power is 300 W; microwave-assisted crystallization to obtain a dark blue mixture; after the reaction kettle is cooled to room temperature, centrifugation is performed, and the obtained dark blue substance is washed with N,N-dimethylformamide and anhydrous ethanol for 3 times respectively, and then transferred to a 90°C vacuum drying box for vacuum drying for 10 h to obtain porous HKUST-1.

[0033] Preparation Example 5

[0034] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Dissolve copper salt (21 mmol of copper chloride) and trimesic acid (21 mmol) in 200 mL of N,N-dimethylformamide, add 50 mL of anhydrous ethanol and stir to form a blue suspension, and stir uniformly to obtain a mixture; S2. The mixture was transferred to a microwave reactor, and a temperature program was set to heat up to 75℃ at a rate of 2℃ / min and then keep for 4h, and then heat up to 120℃ at a rate of 5℃ and keep for 16h, with a power of 300W. Microwave-assisted crystallization was performed to obtain a dark blue mixture. After the reactor was cooled to room temperature, the dark blue material was washed with N,N-dimethylformamide and anhydrous ethanol for 3 times, respectively, and then transferred to a 100℃ vacuum drying oven for vacuum drying for 12h to obtain porous HKUST-1.

[0035] Preparation Example 6

[0036] The present preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. Copper salt (33.4mmol of copper chloride) and trimesic acid (66.8mmol) were dissolved in 100mL of N,N-dimethylformamide, 67mL of anhydrous ethanol was added and stirred to form a blue suspension, and the mixture was stirred uniformly to obtain a mixture; S2. The mixture was transferred to a microwave reactor, and a temperature program was set to heat up to 75℃ at a rate of 2℃ / min and then keep for 4h, and then heat up to 120℃ at a rate of 5℃ and keep for 16h, with a power of 300W. Microwave-assisted crystallization was performed to obtain a dark blue mixture. After the reactor was cooled to room temperature, the dark blue material was washed with N,N-dimethylformamide and anhydrous ethanol for 3 times, respectively, and then transferred to a 100℃ vacuum drying oven for vacuum drying for 12h to obtain porous HKUST-1.

[0037] Example 1

[0038] A method for preparing a metal organic framework coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 7%, and porous HKUST-1 prepared in Preparation Example 1 was added to the solution, with a mass ratio of porous HKUST-1 to PVDF-HFP / NMP solution of 0.55:1. The mixture was stirred uniformly to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 50℃ to obtain a metal organic framework coated aluminum foil current collector.

[0039] Example 2

[0040] A method for preparing a metal organic framework coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 7%, and porous HKUST-1 prepared in Preparation Example 2 was added thereto, the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.58:1; the mixture was stirred to be uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 50°C to obtain a metal-organic framework coated aluminum foil current collector.

[0041] Example 3

[0042] A method for preparing a metal-organic framework coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 8%, and porous HKUST-1 prepared in Preparation Example 3 was added thereto, the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.56:1; the mixture was stirred to be uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 50°C to obtain a metal-organic framework coated aluminum foil current collector.

[0043] Example 4

[0044] A method for preparing a metal-organic framework coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 8%, and porous HKUST-1 prepared in Preparation Example 4 was added thereto, the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.6:1; the mixture was stirred to be uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 60°C to obtain a metal-organic framework coated aluminum foil current collector.

[0045] Example 5

[0046] A method for preparing a metal-organic framework coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 5%, and porous HKUST-1 prepared in Preparation Example 1 was added to the solution, with the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.6:1; the mixture was stirred until uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 50°C to obtain a metal-organic framework-coated aluminum foil current collector.

[0047] Example 6

[0048] A method for preparing a metal-organic framework-coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 10%, and porous HKUST-1 prepared in Preparation Example 1 was added to the solution, with the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.5:1; the mixture was stirred until uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on an aluminum foil using a coating machine, and the aluminum foil was sufficiently dried at 70°C to obtain a metal-organic framework-coated aluminum foil current collector.

[0049] Comparative Preparation Example 1

[0050] This comparative preparation example provides a method for preparing porous HKUST-1, comprising the following steps: S1. same as Example 4; S2. The mixture was transferred to a polytetrafluoroethylene liner and incubated at 160°C for 10 hours to obtain a blue mixture; after the reaction kettle was cooled to room temperature, the blue substance obtained was washed with N,N-dimethylformamide and anhydrous ethanol for 3 times respectively, and then transferred to a vacuum drying oven at 90°C for vacuum drying for 10 hours to obtain porous HKUST-1.

[0051] Comparative Example 1

[0052] A method for preparing a metal-organic framework-coated aluminum foil current collector, comprising the following steps: Step 1: preparing a coating slurry; PVDF-HFP was dissolved in NMP to obtain a PVDF-HFP / NMP solution with a mass concentration of 8%, and porous HKUST-1 prepared in Comparative Preparation Example 1 was added to the solution, with the mass ratio of porous HKUST-1 to the PVDF-HFP / NMP solution being 0.6:1; the mixture was stirred until uniform to obtain a coating slurry; Step 2: coating and drying; The coating slurry was uniformly coated on the aluminum foil using a coater, and dried at 60℃ to obtain a metal organic framework coated aluminum foil current collector.

[0053] Comparative Example 2

[0054] A PVDF-HFP / NMP solution with a mass concentration of 7% was uniformly coated on the aluminum foil using a coater, and dried at 50℃ to obtain a coated aluminum foil current collector.

[0055] The ion migration rate of the metal organic framework coated aluminum foil current collector prepared in the above examples and comparative examples was evaluated by electrochemical method, the charge-discharge efficiency was compared by assembling an electrochemical workstation through a classic button cell, and the conductivity was measured by impedance test, and the results are shown in Table 1.

[0056] Table 1

[0057] Compared with the prior art, the charge-discharge efficiency of the button cell of the aluminum foil of the prior art was 67-80% at the same rate (3C), and the conductivity was (0.5-0.8) x 10 -2 s / m; As can be seen from the data in Table 1, the charge-discharge efficiency and conductivity of the metal organic framework coated aluminum foil current collector prepared in the examples are obviously improved compared with the prior art; Specifically, as can be seen from Example 4 and Comparative Example 1, Comparative Example 1 uses a hydrothermal method to prepare hierarchical HKUST-1, and Example 4 uses a microwave-assisted heating method, and the ion migration number and conductivity are improved compared with Comparative Example 1, indicating that the microwave-assisted heating method not only shortens the crystallization time and improves the crystallization efficiency, but also improves the electrochemical performance of the prepared coated aluminum foil; and the microwave-assisted heating also has the advantages of high efficiency and energy saving.

[0058] The preparation method of the metal organic framework coated aluminum foil provided by the application has a HKUST-1 functional coating layer containing a hierarchical metal organic framework structure on the surface of the double-sided aluminum foil. The porous structure of the metal organic framework material MOF allows the ions to be uniformly distributed inside the material, providing a fast ion transport path. The three-dimensional porous network constructed on the surface of the aluminum foil provides an electronic conduction and ion diffusion channel, thereby improving the sodium ion charge-discharge efficiency and ion conductivity, and improving the electrochemical performance of the battery.

[0059] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; thus the use of any

[0060] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims below and their equivalents.

Claims

1. A metal organic framework-coated aluminum foil current collector, characterized by, The porous HKUST-1 is prepared by the following steps:

2. The MOF-coated aluminum foil current collector of claim 1, wherein, S1. Dissolving copper salt and trimesic acid in N,N-dimethylformamide, adding anhydrous ethanol and stirring to form a blue suspension, and stirring to obtain a mixture; S2. Transferring the mixture into a reaction kettle, microwave-assisted crystallization, centrifuging, washing, and vacuum drying the deep blue mixture to obtain the porous HKUST-1. The copper salt is any one or more of copper chloride, copper sulfate, copper nitrate, copper bromide or copper acetate in any proportion.

3. The MOF-coated aluminum foil current collector of claim 2, wherein, In S1, the volume ratio of anhydrous ethanol to N,N-dimethylformamide is 2-8:

10.

4. The MOF-coated aluminum foil current collector of claim 2, wherein, In the mixture, the molar concentration of trimesic acid is 0.08-0.5 mol / L, and the molar ratio of copper salt to trimesic acid is 1:(1-5).

5. The MOF-coated aluminum foil current collector of claim 2, wherein, In S2, the process conditions for microwave-assisted crystallization are as follows: setting a temperature rising program to rise at a rate of 1-3℃ / min to 65-85℃, then holding for 2-5h, and then rising at a rate of 4-6℃ to 100-160℃ for 8-22h, with a power of 200-400W.

6. The MOF-coated aluminum foil current collector of claim 2, wherein, In S2, the vacuum drying temperature is 50-90℃, and the vacuum drying time is 10-12h.

7. The MOF-coated aluminum foil current collector of claim 2, wherein, The method comprises the following steps:

8. A method for preparing a metal-organic framework-coated aluminum foil current collector for use in the metal-organic framework-coated aluminum foil current collector according to any one of claims 1 to 7, characterized in that, Step 1: Dissolving PVDF-HFP in NMP to obtain a PVDF-HFP / NMP solution, adding porous HKUST-1 to the solution, stirring to mix uniformly, and obtaining a coating slurry; Step 2: Coating the coating slurry uniformly on an aluminum foil, and drying to obtain a metal-organic framework coated aluminum foil current collector. In step 1, the mass concentration of the PVDF-HFP / NMP solution is 5%-10%.

9. The method of claim 8, wherein the metal organic framework-coated aluminum foil current collector is prepared by the steps of: In step 1, the mass ratio of porous HKUST-1 to PVDF-HFP / NMP solution is (1-3):(0.5-2).

10. The method of claim 8, wherein the metal organic framework-coated aluminum foil current collector is prepared by the steps of: ​

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