MOF-based composite material for flexible lithium ion battery and preparation method of MOF-based composite material
By preparing composite materials of MOF with PEO and carbon oxide nanotubes, the problems of low specific capacity and stability of flexible lithium-ion battery anode materials were solved, realizing a flexible electrode material with high energy density and long life.
Patent Information
- Application Number
- CN202510989958.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-17
- Publication Date
- 2025-10-31
AI Technical Summary
The theoretical specific capacity of graphite, the existing flexible lithium-ion battery anode material, is low and it is easy to detach, which leads to a sharp reduction in battery life and cannot meet the high energy density and stability requirements of wearable devices.
MOF nanoparticles were prepared by hydrothermal reaction using a metal-organic framework (MOF) and polyethylene oxide (PEO) composite material, and then combined with carbon oxide nanotubes to form a highly viscoelastic polymer substrate, which enhances the stability and conductivity of the material.
It improves the specific capacity and structural stability of flexible electrode materials, ensures the effective transport of lithium ions inside the electrode, reduces the shedding of active materials, and extends battery life.
Smart Images
Figure CN120865692A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flexible lithium-ion battery anode material preparation technology, specifically relating to a preparation method based on a flexible composite material of metal-organic framework (MOF) and polyethylene oxide (PEO). Background Technology
[0002] As one of the most widely used rechargeable batteries, lithium-ion batteries play an irreplaceable role in people's lives and are widely used in most portable devices and electric vehicles. They possess advantages such as high energy density, small size, good cycle stability, and safety and reliability. However, the theoretical specific capacity of graphite, currently a commercially available anode material for lithium-ion batteries, is low, only 372 mAh / g, and is accompanied by inevitable capacity decay. Therefore, there is an urgent need to develop new anode materials to replace graphite. Meanwhile, the emergence of flexible lithium-ion batteries in recent years has greatly expanded the application range of lithium-ion batteries, making their application in high-energy-consuming wearable devices possible. Currently, the wearable device field urgently needs to develop flexible lithium-ion batteries that are bendable, foldable, and have high specific energy. It is well known that the electrochemical performance of lithium-ion batteries is highly dependent on the redox component—the electrode material. Developing high-energy-density flexible electrode materials is of great significance for flexible lithium-ion batteries. In existing flexible electrode fabrication processes, a common method is to coat the electrode material onto a flexible substrate, with the connection between the active material and the substrate relying on physical bonding. However, flexible electrodes prepared by this process are prone to detachment of active materials when in contact with electrolyte, resulting in a sharp reduction in battery life. Summary of the Invention
[0003] Therefore, the technical problem to be solved by the present invention is to overcome the stability problem caused by traditional coating processes and to prepare metal-organic framework-based flexible electrode materials with high energy density and high stability.
[0004] To this end, the present invention provides the following technical solution.
[0005] (1) Sulfates, chlorides, or nitrates of transition metals are dissolved with the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) in a mixed solution of N,N-dimethylformamide (DMF), water, and methanol. Metal-organic framework (MOF) materials are obtained through hydrothermal self-assembly.
[0006] (2) Polyethylene oxide (PEO) polymer and lithium bis(fluorosulfonyl)imide (LiFSI) were dissolved in anhydrous acetonitrile to prepare a polymer precursor solution.
[0007] (3) Add carbon nanotubes to the polymer precursor prepared in step (2) and stir to obtain a polymer substrate.
[0008] (4) The MOF material prepared in step (1) is added to the polymer substrate prepared in step (3), and the MOF material is uniformly distributed in the polymer substrate by stirring. Finally, a film is cast on a polytetrafluoroethylene plate and dried in an oven to obtain a flexible composite material.
[0009] The transition metal in step (1) is at least one of copper, nickel, ferrous iron, and cobalt; preferably copper nitrate, nickel nitrate, cobalt nitrate, or ferrous nitrate; the ratio of the sulfate, chloride, or nitrate of the transition metal to the organic ligand DHTA is (2-4) mmol:(1-2) mmol; the ratio of DMF, water, and methanol is (30-50) ml:(5-10) ml:(5-10) ml.
[0010] The hydrothermal reaction temperature in step (1) is (100-140)℃, the holding time is (24-48)h, and the heating rate is 2-5℃ / min.
[0011] In step (2), the ratio of PEO, LiFSI and anhydrous acetonitrile is (1-2)g:(0.3-0.5)g:(20-30)ml, the stirring speed is 800rpm, and the time is (5-10)h.
[0012] In step (3), the amount of carbon nanotubes used is (0.05-0.1) mg, the stirring rate is 800 rpm, and the time is (5-10) h.
[0013] In step (4), the amount of MOF material used is (0.1-0.5) g, the stirring rate is 800 rpm, and the time is (5-10) h. The drying temperature is (60-80) ℃, and the time is (12-24) h.
[0014] This invention not only provides a flexible composite material based on MOF and PEO obtained according to the above preparation method, but also provides an application scheme for the flexible composite material based on MOF and PEO obtained according to the above preparation method in lithium-ion battery anode materials.
[0015] The technical solution of this invention has the following advantages:
[0016] 1. The method for preparing flexible composite materials based on MOF and PEO provided by the present invention includes four steps: preparation of MOF material, preparation of polymer precursor solution, preparation of polymer substrate, and preparation of flexible composite material.
[0017] The MOF material obtained by this method is a mixture of nanospheres and irregular shapes. This structure can increase the specific surface area and active sites based on the nanopores of the MOF material, thereby improving the lithium storage capacity of the MOF material. At the same time, the porous nature of the MOF material itself can adapt to the volume changes caused by the insertion / extraction of lithium ions during lithiation and delithiation, providing a buffer space and improving the structural stability of the material.
[0018] 2. The method for preparing flexible composite materials based on MOF and PEO provided by this invention improves the conductivity of the prepared polymer substrate by adding carbon nanotubes to the polymer precursor solution. Simultaneously, the inherent pores of the carbon nanotubes provide an effective pathway for lithium ion transport within the electrode. Furthermore, the presence of oxidized functional groups such as carboxyl and hydroxyl groups on the surface of the carbon nanotubes enables them to form numerous hydrogen bonds with PEO, thereby ensuring the stable existence of the carbon nanotubes within the polymer substrate.
[0019] 3. The method for preparing flexible composite materials based on MOF and PEO provided by this invention selects the oxygen-rich organic ligand DHTA to synthesize the metal-organic framework, effectively utilizing the hydrogen bonds between H and O to stabilize the presence of the MOF active material in the polymer substrate. Simultaneously, the highly viscoelastic polymer substrate formed by PEO can further limit the volume changes caused by lithium ion insertion / extraction during lithiation and delithiation processes, and effectively hinder the dissolution of the MOF active material in the electrolyte. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is the XRD pattern of the metal-organic framework (Co-DHTA MOF) in Embodiment 1 of the present invention;
[0022] Figure 2 This is a scanning electron microscope (SEM) image of the Co-DHTA MOF in Embodiment 1 of the present invention;
[0023] Figure 3 This is the infrared spectrum of the Co-DHTA MOF in Embodiment 1 of the present invention;
[0024] Figure 4 This is an image of the flexible composite material based on Co-DHTAMOF and PEO in Embodiment 1 of the present invention.
[0025] Figure 5 This is the specific capacity-voltage curve of the flexible composite material based on Co-DHTA MOF and PEO in Embodiment 1 of the present invention when used as a negative electrode material for lithium-ion batteries.
[0026] Figure 6 This is a cycle stability diagram of the flexible composite material based on Co-DHTA MOF and PEO in Embodiment 1 of the present invention when used as a negative electrode material for lithium-ion batteries.
[0027] Figure 7 The images show the Raman spectra of the polymer substrate with carbon nanotubes added without oxides obtained in Comparative Example 2 of this invention and the flexible composite material based on Co-DHTA MOF and PEO obtained in Example 1. Detailed Implementation
[0028] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.
[0029] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0030] Example 1
[0031] Example 1 provides a method for preparing flexible composite materials based on metal-organic framework materials (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0032] (1) Preparation of metal-organic frameworks (Co-DHTA MOF): 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonication time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0033] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0034] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0035] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0036] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0037] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0038] Figure 1 This is the XRD pattern of the Co-DHTA MOF nanoparticles prepared in this embodiment;
[0039] Figure 2 This is a scanning electron microscope (SEM) image of the Co-DHTA MOF material prepared in this embodiment;
[0040] Figure 3 This is the infrared spectrum of the Co-DHTA MOF material prepared in this embodiment;
[0041] Figure 4 This is the infrared spectrum of the flexible composite material based on Co-DHTA MOF and PEO prepared in this embodiment;
[0042] Figure 5 Images of the flexible composite material based on Co-DHTA MOF and PEO prepared in this embodiment are shown. The specific methods for testing the electrochemical performance of the flexible composite material prepared in this embodiment are as follows:
[0043] (1) Electrode preparation: The negative electrode was cut into 11mm diameter pieces using an 11mm cutter. The mass of each piece was weighed using a precision balance, and the mass of the active material Co-DHTA MOF was calculated based on the solid raw material ratio. The electrodes were then placed in an argon-atmosphere glove box to assemble a half-cell. The negative electrode shell, lithium sheet, PP separator, electrolyte, flexible composite electrode, gasket, and spring were added sequentially to complete the battery assembly. The battery was then sealed using a button cell sealing machine. The battery model was CR2025 button cell, and the electrolyte was LiPF6 / EC+DEC, where EC is ethylene carbonate, DEC is diethyl carbonate, and PP is polypropylene. The battery was removed from the glove box and allowed to stand for 24 hours before its electrochemical performance was measured.
[0044] (2) Half-cell performance testing: On the Xinwei battery charge-discharge tester, under constant current charge-discharge conditions with a charge-discharge voltage range of 0.01-3V and a current density of 200mA / g, the charge specific capacity, cycle efficiency, and cycle stability of the coin cell were tested and analyzed after 100 cycles. The coulombic efficiency of each cycle was above 95%, and after 100 cycles, the specific capacity exceeded 500mAh / g.
[0045] Figure 6 This is a cycle stability diagram of the flexible composite material in this embodiment when used as a negative electrode material for a lithium-ion battery.
[0046] Example 2
[0047] Example 2 provides a method for preparing flexible composite materials based on metal-organic framework materials (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0048] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 100 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0049] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.5g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0050] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0051] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0052] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.3g of the material from step (1) was used.
[0053] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0054] Example 3
[0055] Example 3 provides a method for preparing flexible composite materials based on metal-organic framework materials (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0056] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 140 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0057] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0058] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0059] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0060] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.3g of the material from step (1) was used.
[0061] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0062] Example 4
[0063] Example 4 provides a method for preparing flexible composite materials based on metal-organic framework materials (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0064] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature and then filtered in a fume hood or centrifuged to obtain Co-DHTA MOF nanoparticles. These were then dried in a 60 °C oven for later use. The ultrasonic treatment time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0065] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0066] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0067] (3) Preparation of polymer substrate: 0.05 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring speed was 800 rpm.
[0068] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0069] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0070] Example 5
[0071] Example 5 provides a method for preparing flexible composite materials based on metal-organic framework materials (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0072] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt chloride hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0073] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0074] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0075] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0076] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0077] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0078] Example 6
[0079] Example 6 provides a method for preparing a flexible composite material based on metal-organic framework (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0080] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt sulfate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the Co-DHTA MOF nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonication time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, and the centrifugation time was 10 min.
[0081] min / cycle, speed is 8000 rpm.
[0082] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0083] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0084] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0085] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0086] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0087] Example 7
[0088] Example 7 provides a method for preparing a flexible composite material based on metal-organic framework (Cu-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0089] (1) Preparation of Cu-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of copper nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature and then filtered in a fume hood or centrifuged to obtain Cu-DHTA MOF nanoparticles. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0090] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0091] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0092] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0093] (4) Preparation of flexible composite material based on Cu-DHTA MOF and PEO: 0.2g of step (1)
[0094] The prepared Cu-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Cu-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0095] Example 8
[0096] Example 8 provides a method for preparing a flexible composite material based on metal-organic framework (Ni-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0097] (1) Preparation of Ni-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of nickel nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature and then filtered in a fume hood or centrifuged to obtain Ni-DHTA MOF nanoparticles. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0098] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0099] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0100] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0101] (4) Preparation of flexible composite material based on Ni-DHTA MOF and PEO: 0.2g of Ni-DHTA MOF nanoparticles prepared in step (1) were added to the polymer substrate prepared in step (3) and stirred for 5h to ensure uniform dispersion. Then, it was cast onto a polytetrafluoroethylene plate and dried in an oven at 60℃ for 24h to obtain the flexible composite material based on Ni-DHTA MOF and PEO. The stirring rate was 800rpm.
[0102] Example 9
[0103] Example 9 provides a method for preparing a flexible composite material based on a metal-organic framework (Co-DHTA MOF) and polyethylene oxide (PEO), specifically including the following steps:
[0104] (1) Preparation of Co-DHTA MOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 36 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0105] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0106] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0107] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0108] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0109] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0110] Example 10
[0111] Example 10 provides a method for preparing a flexible composite material based on a metal-organic framework (Co-DHTAMOF) and polyethylene oxide (PEO), specifically including the following steps:
[0112] (1) Preparation of Co-DHTAMOF: 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and kept at 120 °C for 48 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonic time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0113] (2) Preparation of polymer precursor solution: 1.5g PEO and 0.3g lithium bis(fluorosulfonyl)imide (LiFSI) were mixed.
[0114] Dissolve the acetonitrile in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm.
[0115] (3) Preparation of polymer substrate: 0.1 g of carbon oxide nanotubes were added to the polymer precursor solution prepared in step (2) and stirred for 5 h to disperse it evenly. The stirring rate was 800 rpm.
[0116] (4) Preparation of flexible composite materials based on Co-DHTA MOF and PEO: 0.2g of the material from step (1) was used.
[0117] The prepared Co-DHTA MOF nanoparticles were added to the polymer substrate prepared in step (3) and stirred for 5 hours to ensure uniform dispersion. Then, the mixture was cast onto a polytetrafluoroethylene (PTFE) plate and dried in a 60°C oven for 24 hours to obtain a flexible composite material based on Co-DHTA MOF and PEO. The stirring rate was 800 rpm.
[0118] Example description:
[0119] By changing the type of cobalt salt in step (1) of the examples, as well as the nitrates of different transition metals, hydrothermal temperature, reaction time, and other conditions, it was found that within the range of 100-140℃, there was no significant effect on the synthesis of metal-organic frameworks (MOFs), with only a slight increase in particle size with increasing reaction time. By changing the amount of lithium bis(fluorosulfonyl)imide (LiFSI) in step (2), it was found that within the soluble range, there was a beneficial tendency with increasing lithium salt content. By changing the amount of carbon oxide nanotubes in step (3), it was found that there was a small impact on performance, which can be attributed to the conductivity of the flexible composite material. By changing the amount of MOF in step (4), it was found that the electrochemical performance was almost unchanged, indicating that within a certain range, MOFs are well dispersed in the polymer substrate.
[0120] Comparative Example 1
[0121] Preparation of metal-organic frameworks (Co-DHTA MOF): 4 mmol of the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) and 2 mmol of cobalt nitrate hexahydrate were ultrasonically dissolved in a mixed solution of 40 ml N,N-dimethylformamide (DMF), 10 ml water, and 10 ml methanol. The mixed solution was transferred to a reaction vessel and incubated at 120 °C for 24 h. After the reaction was completed, the reaction vessel was cooled to room temperature, and the nanoparticles were obtained by filtration in a fume hood or centrifugation. The nanoparticles were then dried in a 60 °C oven for later use. The ultrasonication time was 5 min, the hydrothermal reaction heating rate was 5 °C / min, the centrifugation time was 10 min / cycle, and the rotation speed was 8000 rpm.
[0122] Comparative Example 2
[0123] Preparation of the carbon nanotube-free polymer substrate: 1.5 g of polyethylene oxide (PEO) and 0.3 g of lithium bis(fluorosulfonyl)imide (LiFSI) were dissolved in 20 ml of anhydrous acetonitrile by stirring for 30 min at a stirring speed of 800 rpm. After uniform dispersion, the solution was cast onto a polytetrafluoroethylene (PTFE) plate and dried in an oven at 60 °C for 24 h to obtain the carbon nanotube-free polymer substrate.
[0124] Comparison of proportions:
[0125] The Co-DHTA MOF obtained in Comparative Example 1 is consistent with that obtained in Example 1. The Raman spectrum of the polymer substrate without added carbon nanotubes obtained in Comparative Example 2 is as follows: Figure 7 As shown.
[0126] Obviously, the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method for preparing a flexible composite material based on metal-organic frameworks (MOFs) and polyethylene oxide (PEO), specifically comprising the following steps: (1) The sulfate, chloride or nitrate salts of transition metals and the organic ligand 2,5-dihydroxyterephthalic acid (DHTA) are dissolved in a mixed solution of N,N-dimethylformamide (DMF), water and methanol. The MOF material is obtained by self-assembly through hydrothermal reaction. (2) PEO polymer and lithium bis(fluorosulfonyl)imide (LiFSI) were dissolved in anhydrous acetonitrile to prepare a polymer precursor solution. (3) Add carbon nanotubes to the polymer precursor prepared in step (2) and stir to obtain a polymer substrate. (4) The MOF nanoparticles prepared in step (1) are added to the polymer substrate prepared in step (3), and the mixture is stirred to ensure that the MOF material is uniformly distributed in the polymer substrate. Finally, the film is cast onto a polytetrafluoroethylene plate and dried in an oven to obtain a flexible composite material.
2. The preparation method according to claim 1, characterized in that, The transition metal in step (1) is at least one of copper, ferrous iron, nickel, and cobalt; the ratio of the sulfate, chloride, or nitrate of the transition metal to the organic ligand DHTA is (2-4) mmol: (1-2) mmol; the ratio of DMF, water, and methanol is (30-50) ml: (5-10) ml: (5-10) ml. The hydrothermal reaction temperature in step (1) is (100-140)℃, the holding time is (24-48)h, and the heating rate is 2-5℃ / min.
3. The preparation method according to claim 1 or 2, characterized in that, In step (2), the ratio of PEO, lithium bis(fluorosulfonyl)imide (LiFSI), and anhydrous acetonitrile is (1-2) g : (0.3-0.5) g : (20-30) ml, stirring speed 800 rpm, time (5-10) h.
4. The preparation method according to claims 1-3, characterized in that, In step (3), the amount of carbon nanotubes used is (0.05-0.1) mg, the stirring rate is 800 rpm, and the time is (5-10) h.
5. The preparation method according to claims 1-4, characterized in that, In step (4), the amount of MOF used is (0.1-0.5) g, the stirring rate is 800 rpm, and the time is (5-10) h. The drying temperature is (60-80) ℃, and the time is (12-24) h.
6. The flexible composite material based on MOF and PEO prepared by the preparation method according to any one of claims 1 to 5.
7. The application of the flexible composite material based on MOF and PEO prepared by the preparation method according to any one of claims 1 to 5, or the flexible composite material based on MOF and PEO according to claim 6, in the anode material of lithium-ion batteries.