A polyimide covalent organic framework (COF) material containing porphyrin units, an electrode and a preparation method

Abstract

The application discloses a kind of polyimide COF materials containing porphyrin unit, electrode and preparation method, it is related to battery electrode material technical field, including: 5,10,15,20-tetra (4-aminophenyl) porphyrin is polymerized with the solvent containing anhydride, is transferred to hydrothermal reactor and is reacted, obtains the polyimide COF containing porphyrin unit of organic covalent framework;Washing, remove solvent, dry, obtain the polyimide COF material containing porphyrin unit.Copper foil is obtained by stirring, smearing, coating on copper foil by adding porphyrin unit polyimide COF material with conductive carbon black, polyvinylidene fluoride in N-methylpyrrolidone.The beneficial effects of the present application are that the porphyrin unit polyimide COF material contains a large number of active sites, which can effectively improve the charge transport efficiency of the material, solve the problems of organic small molecules, such as easy to dissolve in electrolyte material, low specific capacity and poor conductivity, improve the specific capacity and capacity retention rate.

Description

Technical Field

[0001] This invention belongs to the field of battery electrode material technology, specifically relating to a polyimide COF material containing porphyrin units, an electrode, and a preparation method thereof. Background Technology

[0002] With the increasing depletion of fossil fuels and the escalation of environmental pollution, energy and environmental issues have become two major challenges facing humanity, and rechargeable batteries have emerged as a crucial solution. Current rechargeable battery electrode materials primarily focus on inorganic materials. These materials utilize the valence changes of transition metals to achieve ion storage, but they are prone to irreversible phase transitions, severely impacting battery stability and rate performance. Furthermore, inorganic electrode materials heavily rely on transition metal resources, resulting in high costs and geographical variability, which is detrimental to long-term environmentally friendly development. Therefore, there is an urgent need to develop clean and alternative electrode materials. Organic electrode materials, with their superior performance and environmental friendliness, demonstrate broad application prospects. In particular, organic materials rich in conjugated structures, due to their efficient charge transport capabilities and structural diversity, have become an important direction for future electrode material research. Through molecular design, these materials can achieve structural controllability, thereby optimizing battery performance and meeting the needs of different application scenarios. With the continuous advancement of energy technology and the increasing awareness of environmental protection, clean and efficient organic electrode materials will play an increasingly important role in lithium-ion batteries and other energy storage devices, providing a solid guarantee for a sustainable energy future. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a polyimide COF material containing porphyrin units, an electrode, and a preparation method thereof, aiming to overcome the technical difficulties of low specific capacity and poor conductivity of traditional organic electrode materials. This invention prepares a series of polyimide COF materials containing porphyrin units. These porphyrin-containing polyimide COF materials not only provide abundant redox sites but also significantly improve the charge transport efficiency of the material. This invention effectively solves the problems of easy solubility of small organic molecules in electrolytes, low specific capacity of organic electrode materials, and poor conductivity. The porous structure of the COF material also allows for sufficient contact between the electrode material and the electrolyte, enabling the material to exhibit excellent performance and stability in secondary batteries. The organic electrode material of this invention has high specific capacity and good conductivity, and can be widely used in high-performance lithium-ion batteries.

[0004] The technical solution of the present invention is as follows:

[0005] In a first aspect, the present invention provides a method for preparing a polyimide COF material containing porphyrin units, comprising the following steps:

[0006] 5,10,15,20-tetra(4-aminophenyl)porphyrin was polymerized with an anhydride-containing solvent to obtain a polyamic acid solution containing porphyrin units;

[0007] The polyamic acid solution containing porphyrin units was transferred to a hydrothermal reactor for reaction to obtain an organic covalent framework polyimide COF containing porphyrin units;

[0008] The organic covalent framework polyimide COF containing porphyrin units was cleaned with a solvent, the solvent was removed, and the material was dried to obtain the polyimide COF material containing porphyrin units.

[0009] Optionally, the acid anhydride includes at least one of BPDA, PMDA, and NTCDA.

[0010] Optionally, the molar ratio of 5,10,15,20-tetrakis(4-aminophenyl)porphyrin to acid anhydride is 0.5~1.5:1.5~2.5. Preferably, it is 0.7~1.3:1.7~2.3; more preferably, it is 0.9~1.1:1.9~2.1.

[0011] Optionally, the mass fraction of the porphyrin-containing polyamic acid solution is 0.5% to 5%. Preferably, it is 1% to 5%; more preferably, it is 2% to 5%.

[0012] Optionally, the solvent is N,N-dimethylacetamide.

[0013] Optionally, the amount of solvent added is 27.7-290 times the mass of 5,10,15,20-tetra(4-aminophenyl)porphyrin.

[0014] Optionally, the polymerization reaction is carried out at -5 to 5 °C for 3 to 6 hours. Preferably, it is carried out at -4 to 4 °C for 4 to 6 hours; more preferably, it is carried out at -3 to 3 °C for 4 to 5 hours.

[0015] Optionally, the reaction temperature of the porphyrin-containing polyamic acid solution in the hydrothermal reactor is 140-200℃, and the reaction time is 64-96 hours. Preferably, the reaction temperature is 160-200℃, and the reaction time is 68-96 hours; more preferably, the reaction temperature is 180-200℃, and the reaction time is 72-96 hours.

[0016] Optionally, the porphyrin-containing polyimide COF is centrifuged 3-5 times with N,N-dimethylacetamide until the eluent is colorless and transparent, then sonicated with deionized water for 0.5-1.5 hours to displace the high-boiling-point DMAC, and then freeze-dried to obtain the porphyrin-containing polyimide COF material.

[0017] Secondly, the present invention provides a polyimide COF material containing porphyrin units, which is prepared by the method described above.

[0018] Thirdly, the present invention provides a method for preparing an electrode, comprising adding a porphyrin-containing polyimide COF material or the aforementioned porphyrin-containing polyimide COF material to N-methylpyrrolidone along with conductive carbon black and polyvinylidene fluoride, wherein the amount of conductive carbon black added is 5%-30% of the mass of the porphyrin-containing polyimide COF material, and the amount of polyvinylidene fluoride added is 5%-20% of the mass of the porphyrin-containing polyimide COF material, stirring for 5-10 hours, and then coating it onto copper foil with a thickness of 30-80 mm to obtain an electrode.

[0019] Preferably, the amount of conductive carbon black added is 5%-20% of the mass of the porphyrin-unit polyimide COF material, and the amount of polyvinylidene fluoride added is 5%-15% of the mass of the porphyrin-unit polyimide COF material; more preferably, the amount of conductive carbon black added is 5%-15% of the mass of the porphyrin-unit polyimide COF material, and the amount of polyvinylidene fluoride added is 5%-10% of the mass of the porphyrin-unit polyimide COF material.

[0020] Fourthly, the present invention provides an electrode prepared by the above-described method.

[0021] This invention has at least one of the following beneficial effects:

[0022] The porphyrin-containing polyimide COF material prepared by this invention contains a large number of active sites, which can effectively improve the charge transport efficiency of the material. The porous structure of the COF material also allows the electrode material to fully contact the electrolyte, enabling the material to exhibit excellent performance and stability in secondary batteries. Furthermore, it can simultaneously solve the problems of organic small molecules being easily soluble in electrolyte materials, low specific capacity of organic electrode materials, and poor conductivity, and can be used as a high-performance organic electrode material in secondary batteries.

[0023] Electrodes prepared using the porphyrin-containing polyimide COF material of the present invention can be used in lithium-ion batteries. Compared with the prior art, the specific capacity and capacity retention of batteries prepared using the electrodes of the present invention are significantly higher than those of PI materials with the same structural unit. Attached Figure Description

[0024] Figure 1 Example 1 at 0.1 A·g -1 Capacity retention test graph after 10 cycles at current density;

[0025] Figure 2 Example 4 at 5A·g -1 Capacity retention test graph after 10,000 cycles at current density;

[0026] Figure 3 Comparative Examples 1 and 2 were prepared at 0.5 A·g -1 The specific capacity test graph at the current density. Detailed Implementation

[0027] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following specific embodiments.

[0029] Example 1

[0030] 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) (67.47 mg, 0.1 mmol) and biphenyltetracarboxylic dianhydride (BPDA) (59.42 mg, 0.2 mmol) were dissolved in N,N-dimethylacetamide (DMAC) (14.036 g, 15 mL) and reacted at -1 °C for 4.5 h to obtain a porphyrin-containing polyamic acid solution. The porphyrin-containing polyamic acid was transferred to a reaction vessel and reacted at 140 °C for 72 h to obtain porphyrin-containing polyacrylamide COF. After the reaction was complete, the solution was washed 3-5 times by centrifugation with DMAC until the eluent was colorless and transparent. Then, it was sonicated with deionized water for 1 hour to displace the high-boiling-point DMAC. Finally, the COF powder was obtained by freeze-drying.

[0031] The prepared porphyrin-containing polyimide COF powder was mixed with 10% conductive carbon black and 10% polyvinylidene fluoride, and then added to 4.5 g of N-methylpyrrolidone. The mixture was stirred for 10 hours and then coated onto copper foil to form a 75 mm thick coating, thus obtaining the electrode.

[0032] The electrodes described above were assembled into a button cell. The negative electrode material was polyimide COF, and the counter electrode was lithium metal. The separator material was Celgard 2300, and the electrolyte was 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells were assembled in order from the negative electrode shell to the positive electrode. After sealing with a sealing machine, a testable finished battery was obtained. Figure 1 As shown, when the current density is set to 0.1 A·g -1 After 10 charge-discharge cycles, the specific capacity of the porphyrin-containing polyimide COF was 967.12 mAh·g. -1.

[0033] Example 2

[0034] 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) (67.47 mg, 0.1 mmol) and biphenyltetracarboxylic dianhydride (BPDA) (59.42 mg, 0.2 mmol) were dissolved in N,N-dimethylacetamide (DMAC) (14.036 g, 15 mL) and reacted at -1 °C for 4.5 h to obtain a porphyrin-containing polyamic acid solution. The porphyrin-containing polyamic acid was transferred to a reaction vessel and reacted at 140 °C for 72 h to obtain porphyrin-containing polyacrylamide COF. After the reaction was complete, the solution was washed 3-5 times by centrifugation with DMAC until the eluent was colorless and transparent. Then, it was sonicated with deionized water for 1 hour to displace the high-boiling-point DMAC. Finally, the COF powder was obtained by freeze-drying.

[0035] The prepared porphyrin-containing polyimide COF powder, 10% conductive carbon black, 10% polyvinylidene fluoride, and 4.5 g N-methylpyrrolidone were added and stirred for 5-10 hours. The mixture was then coated onto copper foil to form a 75 mm thick coating, thus obtaining the electrode.

[0036] The above electrodes were assembled into a button cell. The negative electrode material was polyimide COF, and the counter electrode was lithium metal. The separator material was Celgard 2300, and the electrolyte was 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells were assembled from the negative electrode shell to the positive electrode. After sealing, a testable finished battery was obtained. The current density was set to 0.5 A·g. -1 After 10 charge-discharge cycles, the specific capacity of the porphyrin-containing polyimide COF was 897.03 mAh·g. -1 .

[0037] Example 3

[0038] 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) (67.47 mg, 0.1 mmol) and biphenyltetracarboxylic dianhydride (BPDA) (59.42 mg, 0.2 mmol) were dissolved in N,N-dimethylacetamide (DMAC) (14.036 g, 15 mL) and reacted at -1 °C for 4.5 h to obtain a porphyrin-containing polyamic acid solution. The porphyrin-containing polyamic acid was transferred to a reaction vessel and reacted at 140 °C for 72 h to obtain porphyrin-containing polyacrylamide COF. After the reaction was complete, the solution was washed 3-5 times by centrifugation with DMAC until the eluent was colorless and transparent. Then, it was sonicated with deionized water for 1 hour to displace the high-boiling-point DMAC. Finally, the COF powder was obtained by freeze-drying.

[0039] The prepared porphyrin-containing polyimide COF powder was mixed with 10% conductive carbon black and 10% polyvinylidene fluoride, and then added to 4.5 g of N-methylpyrrolidone. The mixture was stirred for 10 hours and then coated onto copper foil to form a 75 mm thick coating, thus obtaining the electrode.

[0040] The above electrodes were assembled into a button cell. The negative electrode material was polyimide COF, and the counter electrode was lithium metal. The separator material was Celgard 2300, and the electrolyte was 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells were assembled from the negative electrode shell to the positive electrode. After sealing, a testable finished battery was obtained. The current density was set to 1.0 A·g. -1 After 10 charge-discharge cycles, the specific capacity of the porphyrin-containing polyimide COF was 818.13 mAh·g. -1 .

[0041] Example 4

[0042] 5,10,15,20-tetratetra(4-aminophenyl)porphyrin (TAPP) (67.47 mg, 0.1 mmol) and biphenyltetracarboxylic dianhydride (BPDA) (59.42 mg, 0.2 mmol) were dissolved in N,N-dimethylacetamide (DMAC) (14.04 g, 15 mL) and reacted at -1 °C for 4.5 h to obtain a porphyrin-containing polyamic acid solution. The porphyrin-containing polyamic acid was transferred to a reaction vessel and reacted at 140 °C for 72 h to obtain porphyrin-containing polyacrylamide COF. After the reaction was complete, the solution was washed 3-5 times by centrifugation with DMAC until the eluent was colorless and transparent. Then, it was sonicated with deionized water for 1 hour to displace the high-boiling-point DMAC. Finally, the COF powder was obtained by freeze-drying.

[0043] The prepared porphyrin-containing polyimide COF powder was mixed with 10% conductive carbon black and 10% polyvinylidene fluoride, and then added to 4.5 g of N-methylpyrrolidone. The mixture was stirred for 10 hours and then coated onto copper foil to form a 75 mm thick coating, thus obtaining the electrode.

[0044] The above electrodes were assembled into a button cell, and the current density was set to 5.0 A·g. -1 The battery uses polyimide COF as the negative electrode material and lithium metal as the counter electrode. The separator material is Celgard 2300, and the electrolyte is 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells are assembled from the negative electrode shell to the positive electrode, and then sealed to obtain a testable finished battery. After 10 charge-discharge cycles, the specific capacity of the porphyrin-containing polyimide COF is 677.6 mAh·g. -1 .

[0045] like Figure 2 The image shows Example 4 at 5A·g -1 Capacity retention test graph at current density, by Figure 2 It can be seen that the button cell prepared in Example 4 has a performance of 5 A·g -1 The capacity retention rate is as high as 71.92% after 10,000 cycles at a current density.

[0046] Comparative Example 1

[0047] The difference from Example 2 is that "5-(4-aminophenyl)-10,15,20-triphenylporphyrin (TPPNH2)" is used instead of "COF powder". The method for preparing the electrode includes: adding 4.5 g of N-methylpyrrolidone to TPPNH2, conductive carbon black (10% of the mass of TPPNH2) and polyvinylidene fluoride (10% of the mass of TPPNH2), stirring for 10 hours, and then coating it on copper foil with a thickness of 75 mm to obtain the TPPNH2 electrode.

[0048] The above electrodes were assembled into a button cell. The negative electrode material was TPPNH2, and the counter electrode was lithium metal. The separator material was Celgard 2300, and the electrolyte was 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells were assembled in order from the negative electrode shell to the positive electrode. After sealing with a sealing machine, a testable finished battery was obtained. Figure 3 As shown, when the current density is set to 0.5 A·g⁻¹, after 10 charge-discharge cycles, the battery's specific capacity is 344.9 mAh·g⁻¹.-1 .

[0049] Comparative Example 2

[0050] The difference from Example 2 is that "biphenyl dianhydride (BPDA)" is used instead of "COF powder". The method for preparing the electrode includes: adding BPDA, conductive carbon black (10% of the mass of BPDA) and polyvinylidene fluoride (10% of the mass of BPDA) to 4.5 g of N-methylpyrrolidone, stirring for 10 hours, and then coating it on copper foil with a thickness of 75 mm to obtain the BPDA electrode.

[0051] The electrodes described above were assembled into a button cell. The negative electrode material was a BPDA electrode, while the counter electrode was lithium metal. The separator material was Celgard 2300, and the electrolyte was 1M LiPF6 dissolved in EC:DMC:EMC at a volume ratio of 1:1:1. In an argon-filled glove box, button half-cells were assembled in order from the negative electrode shell to the positive electrode. After sealing with a sealing machine, a testable finished battery was obtained. Figure 3 As shown, when the current density is set to 0.5 A·g⁻¹, after 10 charge-discharge cycles, the battery's specific capacity is 573.6 mAh·g⁻¹. -1 .

[0052] Results Analysis

[0053] Comparing Example 2 with Comparative Examples 1 and 2, it can be seen that the battery prepared in Example 2 has a lower efficiency of 0.5 A·g. -1 The specific capacity after 10 charge-discharge cycles at the current density is 897.03 mAh·g. -1 The batteries prepared in Comparative Example 1 (TPPNH2) and Comparative Example 2 (BPDA) showed a performance of 0.5 A·g -1 The specific capacity after 10 discharge cycles at the current density was 344.9 mAh·g. -1 and 573.6 mAh·g -1 The specific capacity of Example 2 is significantly higher than that of Comparative Example 1 (TPPNH2) and Comparative Example 2 (BPDA). Therefore, compared with TPPNH2 and BPDA materials, the specific capacity of the polyimide COF material containing porphyrin units of the present invention is significantly improved. Thus, the present invention can improve the specific capacity of batteries by preparing polyimide COF materials containing porphyrin units.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. The application of a polyimide COF material containing porphyrin units in lithium-ion battery anode materials, characterized in that, The preparation method of the polyimide COF material containing porphyrin units includes the following steps: 5,10,15,20-tetra(4-aminophenyl)porphyrin was polymerized with an anhydride-containing solvent to obtain a polyamic acid solution containing porphyrin units; The obtained polyamic acid solution containing porphyrin units was transferred to a hydrothermal reactor for reaction to obtain an organic covalent framework polyimide COF containing porphyrin units; The obtained organic covalent framework polyimide COF containing porphyrin units was cleaned with a solvent, the solvent was removed, and the material was dried to obtain the polyimide COF material containing porphyrin units. The acid anhydride is BPDA; The reaction temperature of the porphyrin-containing polyamic acid solution in the hydrothermal reactor is 140-200 ℃, and the reaction time is 64-96 hours; The molar ratio of the 5,10,15,20-tetrakis(4-aminophenyl)porphyrin to the acid anhydride is 0.5-1.5:1.5-2.5; The mass fraction of the polyamic acid solution containing porphyrin units is 0.5%-5%; the solvent is N,N-dimethylacetamide, and the amount of solvent added is 27.7-290 times the mass of 5,10,15,20-tetra(4-aminophenyl)porphyrin. The polymerization reaction is carried out at -5 to -5 °C for 3 to 6 hours.

2. The application according to claim 1, characterized in that, The porphyrin-containing polyimide COF was centrifuged 3-5 times with N,N-dimethylacetamide until the eluent was colorless and transparent. Then, it was sonicated with deionized water for 0.5-1.5 hours to displace the N,N-dimethylacetamide. After freeze-drying, the porphyrin-containing polyimide COF material was obtained.

3. The application according to claim 1, characterized in that, Porphyrin-containing polyimide COF material, conductive carbon black, and polyvinylidene fluoride are added to N-methylpyrrolidone. The amount of conductive carbon black added is 5%-30% of the mass of the porphyrin-containing polyimide COF material, and the amount of polyvinylidene fluoride added is 5%-20% of the mass of the porphyrin-containing polyimide COF material. The mixture is stirred for 5-10 hours and then coated onto copper foil with a thickness of 30-80 mm to obtain the electrode.

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