Two-dimensional covalent organic framework material connected by imine bond and application thereof in lithium ion battery with 110000 cycle stability
By preparing two-dimensional covalent organic framework materials linked by imine bonds, the problem of insufficient cycle stability of lithium-ion batteries under high current density was solved, and significant improvements in specific capacity, energy density and power density were achieved, especially the excellent performance of maintaining 100% capacity under high cycle number.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2026-03-17
AI Technical Summary
Existing two-dimensional covalent organic framework materials have not yet achieved high-rate performance and ultra-long cycle stability in lithium-ion batteries, failing to meet the high requirements of energy storage systems, renewable energy smart grids, and micro sensors.
By employing two-dimensional covalent organic framework materials linked by imine bonds, COFs materials with high crystallinity and hierarchical porous structures were prepared through specific compound synthesis and processing steps, thereby enhancing the stability of lithium-ion battery cathodes and the accessibility of active centers.
It achieves ultra-long cycle stability of 110,000 cycles at high current density for lithium-ion batteries, maintaining 100% capacity, with a specific capacity of 145 mA h g⁻¹, an energy density of 390 Wh kg⁻¹, and a power density of 1352 W kg⁻¹, demonstrating excellent rate performance and high energy density.
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Figure CN119119460B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic battery materials technology, specifically relating to an imine-bonded two-dimensional covalent organic framework material and its application in lithium-ion batteries with a cycle stability of 110,000 cycles. Background Technology
[0002] Lithium-ion batteries, as an indispensable energy supply device, have had a tremendous impact on our daily lives. Therefore, designing and synthesizing new battery materials to improve their specific capacity, rate performance, and cycle stability has become a hot research topic. Compared to traditional Li-ion batteries... + Compared to inorganic electrodes based on intercalation processes, organic electrodes, based on simple redox reactions, exhibit relatively high specific capacity and can undergo rapid charging. Therefore, organic electrode materials, due to their high capacity and fast charging characteristics, are considered competitive candidates for next-generation lithium-ion batteries and have attracted widespread attention worldwide. However, small-molecule-based organic electrode materials have high solubility in organic electrolytes, which can lead to poor cycle stability. Exploring the synthesis of electrode materials based on insoluble polymers to improve the cycle stability of organic electrode lithium-ion batteries is a feasible approach.
[0003] Covalent organic frameworks (COFs) are a new class of ordered crystalline and porous organic polymers constructed from modular organic building blocks linked by strong covalent bonds. Besides applications in gas separation and storage, energy conversion, sensors, semiconductors, catalysis, and proton conduction, COFs, with their modular structure and designable redox active units, hold great potential as battery electrode materials due to their enhanced chemical / thermal stability associated with strong covalent interactions. Compared to small organic molecules, COFs offer advantages such as abundant redox-active functional groups for improved battery energy storage capacity, permanent porosity and tunable pore size for enhanced ion transport, and stable crystal chemistry for improved cycle stability. Various redox-active organic building blocks, such as acid anhydrides, quinones, finazines, and azo compounds, have been used to construct COF materials as organic electrodes.
[0004] However, existing COFs electrode materials are far from meeting the high requirements of practical lithium-ion battery electrode materials in fields such as energy storage systems, renewable energy smart grids, and micro-sensors, which require high rate performance and ultra-long cycle stability. Clearly, given the long service life and large capacity of lithium batteries used in these fields, even a moderate improvement in cycle stability is crucial for significantly reducing costs and saving energy. Research indicates that improving and increasing the accessibility of redox active sites in COFs can enhance the cycle stability of lithium-ion battery electrodes. Despite numerous experiments using molecular building block design and mesoscale porous structure construction, the meticulous fabrication of COFs-based lithium-ion battery electrodes with ultra-long cycle stability has not yet been achieved. Summary of the Invention
[0005] The purpose of this invention is to provide an imine-bonded two-dimensional covalent organic framework material and its application in lithium-ion batteries with a cycle stability of 110,000 cycles, aiming to solve the problem mentioned in the background art that lithium-ion battery electrode materials must have high rate performance and ultra-long cycle stability.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] An imine-bonded two-dimensional covalent organic framework material, the structural formula of which is as follows:
[0008]
[0009] Furthermore, the preparation method of the covalent organic framework material includes the following steps:
[0010] Step 1: Add 5,12-bis(4-(5,5-dimethyl-1,3-dioxane-2-yl)phenyl)-5,12-dihydroquinoline[2,3-b]acridin-7,14-dione and N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine to o-dichlorobenzene / n-butanol solution and disperse by ultrasonication;
[0011] Step 2: Add the catalyst and ultrasonically disperse it again to form a uniform system;
[0012] Step 3: Perform liquid nitrogen freezing and vacuum degassing on the system;
[0013] Step 4: Under vacuum conditions, use an alcohol torch to seal the tube.
[0014] Step 5: React at 120 degrees Celsius for 72 hours to obtain the crude product;
[0015] Step 6: Wash the crude product with N,N-dimethylformamide and acetone in sequence, filter, and dry under vacuum to obtain a two-dimensional covalent organic framework material.
[0016] Furthermore, in the o-dichlorobenzene / n-butanol solution described in step one, the volume ratio of o-dichlorobenzene to n-butanol is 2:8.
[0017] Furthermore, the liquid nitrogen freezing and vacuum degassing process described in step three is performed at least three times.
[0018] Furthermore, the concentration of the catalyst in step two is 6 mol / L acetic acid.
[0019] Furthermore, the structural formula of the 5,12-bis(4-(5,5-dimethyl-1,3-dioxane-2-yl)phenyl)-5,12-dihydroquinoline[2,3-b]acridin-7,14-dione is as follows:
[0020]
[0021] Furthermore, the structural formula of the N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine is as follows:
[0022]
[0023] Furthermore, the reaction formula for the preparation method of the covalent organic framework material is as follows:
[0024]
[0025] An electrode material comprising an imine-linked two-dimensional covalent organic framework material according to any one of claims 1-8.
[0026] Furthermore, the application of electrode materials in lithium-ion batteries.
[0027] The present invention, by employing the above-described structure, achieves the following technological advancements compared to existing technologies:
[0028] Powder X-ray diffraction and electron microscopy characterization of the covalent organic framework material of this invention show that the covalent organic framework material has high crystallinity and a biporous kgm topology; N2 adsorption-desorption isotherms show that it has hierarchical porosity, with micropore size of approximately 1.3 nm and mesopore size of approximately 3.4 nm; the lithium-ion battery cathode prepared from the covalent organic framework material has a stable modular structure and hierarchical micro / mesoporous characteristics, allowing Li to be absorbed into the organic electrolyte. + and PF6 - Ions fully enter the active center; coupled with its abundant bipolar redox active sites, lithium-ion batteries can achieve a speed of 0.2Ag. -1 It has 145mA hg -1 Specific capacity, 390Wh kg -1 The energy density, and 1352W kg-1 High power density and excellent rate performance (10Ag) -1 100mA hg -1 The capacity is 231Wh / kg. -1 Energy density and 23760Wkg -1 (power density); in particular, this cathode at 10000 mA g -1 After operating at high current density for 150 days, it exhibits an ultra-long cycle stability of 110,000 cycles with a capacity retention of approximately 100%.
[0029] In summary, the electrode material prepared using covalent organic framework materials in this invention exhibits ultra-long cycle stability and is suitable for lithium-ion batteries. Attached Figure Description
[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.
[0031] In the attached diagram:
[0032] Figure 1 The infrared spectrum of the covalent organic framework material of this invention;
[0033] Figure 2 The covalent organic framework material of this invention 13 C CP / MAS NMR spectrum;
[0034] Figure 3 The image shows the XRD pattern of the covalent organic framework material of this invention.
[0035] Figure 4 The accompanying diagram shows the nitrogen adsorption and desorption process of the covalent organic framework material of this invention.
[0036] Figure 5 Characterization of the cycle performance of lithium-ion batteries assembled from the covalent organic framework materials of this invention. Detailed Implementation
[0037] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0038] Example: An imine-bonded two-dimensional covalent organic framework material and its application in lithium-ion batteries with 110,000 cycle stability.
[0039] This embodiment discloses an imine-bonded two-dimensional covalent organic framework material, such as... Figure 1As shown, the covalent organic framework material (QT-COF) is composed of repeating units, which are connected by imine bonds and exhibit the general characteristics of crystals. The covalent organic framework material is formed by polymerizing 5,12-bis(4-(5,5-dimethyl-1,3-dioxane-2-yl)phenyl)-5,12-dihydroquinoline[2,3-b]acridin-7,14-dione (QA-PCH) and N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine (TPPD). The spatial symmetry of the covalent organic framework material is P. 321 The topology type is kgm topology; the structural formula of the covalent organic framework material is as follows: The structural formula of 5,12-bis(4-(5,5-dimethyl-1,3-dioxane-2-yl)phenyl)-5,12-dihydroquinoline[2,3-b]acridin-7,14-dione is as follows: The structural formula of N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine is as follows:
[0040] The N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine, electrolyte, and porous Celgard 2400 membrane used are all commercially available.
[0041] The preparation method of covalent organic framework materials includes the following steps:
[0042] Step 1: Fill a Pyrex tube with 20.78 mg of 5,12-bis(4-(5,5-dimethyl-1,3-dioxane-2-yl)phenyl)-5,12-dihydroquinoline[2,3-b]acridin-7,14-dione, 7.1 mg of N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine, 0.2 ml of o-dichlorobenzene, and 0.8 ml of n-butanol. Place the Pyrex tube into an ultrasonic generator for ultrasonic treatment.
[0043] Step 2: Add 0.1 ml of 6M / L acetic acid to the Pyrex tube. Acetic acid is used as a catalyst. Then place the Pyrex tube into an ultrasonic generator and sonicate for 30 minutes to form the system.
[0044] Step 3: Freeze the ultrasonically treated Pyrex tube in liquid nitrogen, then degas the frozen Pyrex tube under vacuum and thaw it to room temperature; repeat the freezing, vacuum degassing and thawing process three times.
[0045] Step 4: Under vacuum conditions, seal the Pyrex tube with the flame of an alcohol torch, with a sealing length of 15 cm.
[0046] Step 5: React at 120 degrees Celsius for 72 hours to produce a reddish-brown precipitate. Centrifuge to separate the solid and obtain the crude product.
[0047] Step 6: Wash the crude product three times with N,N-dimethylformamide and acetone respectively, collect the product by filtration, and dry it under vacuum at 80 degrees for 12 hours to obtain 18.7 mg of covalent organic framework material, with a yield of 67.1%.
[0048] The reaction formulas for the preparation of covalent organic framework materials are as follows:
[0049]
[0050] Chemical composition, structure determination and crystallinity of covalent organic framework materials
[0051] Using infrared spectroscopy and 13 Chemical composition analysis of covalent organic framework materials was performed using solid-state nuclear magnetic resonance (NMR), and the structure of covalent organic framework materials was characterized using X-ray diffraction (XRD).
[0052] FT-IR spectroscopy showed that the covalent organic framework material (QT-COF) exhibited high activity at 1709, 1325, and 1631 cm⁻¹. -1 Strong vibrational bands appeared at 2850-2960 cm⁻¹, corresponding to the C=O group of QA, the CN unit of TPDA, and the characteristic C=N unit, respectively. -1 The vibrational peaks at the specified locations disappeared, belonging to the initial aliphatic stretching vibration band of QA and the NH stretching vibration band of TPDA, respectively, proving the successful construction of the all-imine framework of the covalent organic framework material. Figure 1 .
[0053] In the solid state of covalent organic framework materials 13 In the CCP / MAS NMR spectrum, the characteristic resonance signal of the imine bond at 158 ppm indicates that TPDA and QA generate imine bonds through a Schiff base condensation reaction, thus yielding a covalent organic framework material, such as... Figure 2 .
[0054] The crystal structure of covalent organic framework materials was revealed using powder X-ray diffraction (PXRD), theoretical simulation, and Pawley refinement. The PXRD spectra of the covalent organic framework materials showed a series of peaks at 1.72°, 2.92°, 3.40°, 4.52°, 5.10°, 6.13°, and 6.80°, corresponding to the (100), (210), (200), (310), (300), (410), and (400) planes, respectively, demonstrating their high purity. Figure 3 .
[0055] N2 adsorption-desorption isotherms were recorded at 77 K to determine the kgm topology and permanent porosity of the covalent organic framework material. Figure 4It can be seen that the covalent organic framework material exhibits a typical integration of type I and type IV curves, and has a large specific surface area of 771 m². 2 g -1 The pore volume is relatively high, at 1.19 cm. 3 g -1 It is very close to the theoretical value of 1.14 cm based on the structural characterization of the structure. 3 g -1 The significant increase in the low-pressure range (P / P0 < 0.1) and the obvious hysteresis loop in the medium-pressure range demonstrate the hierarchical microporous / mesoporous configuration of the covalent organic framework material; this unique dual-pore characteristic not only facilitates ion diffusion but also improves the utilization rate of redox active sites; furthermore, in Figure 4 The illustration shows an aperture distribution concentrated around 1.3 nm and 3.4 nm, as shown in the figure. Figure 4 .
[0056] This invention synthesizes a highly crystalline two-dimensional covalent organic framework material composed of p-type and n-type active centers linked by imine bonds. This material possesses a kgm topology and ordered, bi-level triangular micropores and hexagonal mesopores. Its high crystallinity, high conductivity, unique microporous and mesoporous structure, and abundant redox active sites enable lithium-ion batteries based on this covalent organic framework to exhibit high specific capacity, high energy density, high power density, and excellent rate performance. Specifically, lithium-ion batteries assembled using this covalent organic framework material as the cathode achieve high specific capacity, high energy density, high power density, and excellent rate performance at 10 Ag. -1 It exhibits an ultra-long cycle stability of 110,000 cycles at high current densities with 100% capacity retention.
[0057] Lithium-ion battery manufacturing
[0058] A covalent organic framework material, carbon black (Ketjenblacka), and polyvinylidene fluoride (PVDF) binder were dissolved in N-methylpyrrolidone (NMP) to form a viscous slurry. This slurry was then cast onto aluminum foil and vacuum dried at 85°C for 24 hours to obtain the positive electrode sheet, which served as the electrode material. Pure lithium was used as the negative electrode, with a concentration of 1 mol / L... -1 A LiPF6 EC / EMC ratio of 3:7 (v / v) solution was used as the electrolyte, and porous Celgard 2400 was used as the separator. CR2032 button cells were assembled in an argon-atmosphere glove box (oxygen and water concentrations were maintained below 1 ppm). Lithium-ion batteries can also be made into other types of button cells, and can also be made into other shapes, such as cylindrical cells.
[0059] Lithium-ion battery performance testing
[0060] The prepared lithium-ion batteries were tested on a LAND 2001A instrument at 1.2–4.3 V vs. Li / Li + The performance of the lithium-ion battery based on the covalent organic framework material electrode was tested by constant current charge-discharge cycling within a specified range. At 10 Ag... -1 At current densities, the capacity retention rate is 100% after 110,000 cycles, demonstrating good cycling stability, such as Figure 5 .
[0061] The covalent organic framework material of this invention possesses excellent electrochemical performance. As a cathode material for lithium-ion batteries, it exhibits high specific capacity and outstanding cycle performance, making it an excellent cathode material for lithium-ion batteries.
[0062] The parts of this invention not described in detail are common knowledge to those skilled in the art.
[0063] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. An imine-linked two-dimensional covalent organic framework material, characterized in that: The preparation method of the covalent organic framework material comprises the following steps: Step one, 5, 12-di (4- (5, 5-dimethyl-1, 3-dioxane-2-yl) phenyl) -5, 12-dihydroquinoline [2, 3-b] acridine-7, 14-dione and N, N, N', N'-tetra (p-aminophenyl) p-phenylenediamine are added to an o-dichlorobenzene / n-butanol solution and ultrasonic dispersion is carried out; Step two, a catalyst is added, and ultrasonic dispersion is carried out again to form a system; Step three, the system is subjected to liquid nitrogen freezing and vacuum degassing treatment; Step four, under vacuum condition, tube sealing operation is carried out by using an alcohol lamp; Step five, reaction is carried out at 120 degrees for 72 hours to obtain a crude product; Step six, the crude product is washed with N,N-dimethylformamide and acetone in turn, and is filtered and dried in vacuum to obtain a two-dimensional covalent organic framework material; the structural formula of the covalent organic framework material is: .
2. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: In the o-dichlorobenzene / n-butanol solution in step one, the volume ratio of o-dichlorobenzene to n-butanol is 2:
8.
3. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: The liquid nitrogen freezing and vacuum degassing treatment in step three is carried out at least 3 times.
4. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: The concentration of the catalyst in step two is 6 mol / L acetic acid.
5. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: The structural formula of the 5, 12-di (4- (5, 5-dimethyl-1, 3-dioxane-2-yl) phenyl) -5, 12-dihydroquinoline [2, 3-b] acridine-7, 14-dione is as follows: .
6. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: The structural formula of the N,N,N',N'-tetra-(p-aminophenyl)-p- phenylenediamine is as follows: .
7. The imine-linked two-dimensional covalent organic framework material of claim 1, wherein: The reaction equation of the preparation method of the covalent organic framework material is as follows: .
8. An electrode material, characterized by: An imine bond connected two-dimensional covalent organic framework material according to any one of claims 1-7.
9. Use of the electrode material according to claim 8 in a lithium ion battery.