Imidazole-modified imide derivative, synthesis method and application of imidazole-modified imide derivative in flow battery

Abstract

The invention discloses imidazole-modified imide derivatives, a synthesis method and application of the imidazole-modified imide derivatives in a flow battery, and belongs to the technical field of flow battery electrolyte materials. According to the imide derivative, by increasing water-soluble groups and optimizing the molecular structure, the water solubility, conjugacy and electron transfer efficiency of the imide derivative are remarkably improved, and the problems that a traditional anode electrolyte material is insufficient in conjugacy and poor in dual-electron storage stability are solved; the synthesis method is simple, efficient and suitable for large-scale production. A neutral aqueous flow battery system constructed by the derivative, an imidazole functionalized TEMPO positive electrode electrolyte and a DSVN anion exchange membrane as a flow battery negative electrode electrolyte shows high solubility, wide output voltage, low oxidation-reduction potential and dual-electron transfer stability, and provides a key material for developing a high-performance neutral aqueous organic flow battery; the method has a wide application prospect of commercial large-scale energy storage, and plays an important role in promoting the development of a clean energy storage technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolyte materials for liquid flow batteries, and in particular relates to a class of imidazole-modified imide derivatives, a synthesis method and an application thereof in liquid flow batteries. Background Art

[0002] In the context of global energy transformation, with the rapid growth of demand for clean energy, especially the widespread application of renewable energy such as solar and wind energy, how to effectively solve its inherent intermittent and uneven geographical distribution problems has become a key challenge to achieve sustainable energy supply. To this end, exploring and developing new efficient and large-scale energy storage technologies has become a common goal of scientific research and industry.

[0003] Liquid flow energy storage technology, especially aqueous flow batteries (RFBs), stands out due to its unique advantages. Compared with traditional energy storage methods, flow batteries can achieve independent regulation of output power and storage capacity, thereby meeting the needs of different application scenarios. Since NASA first proposed the concept of flow batteries in 1974, after half a century of development, flow battery technology has made significant progress, covering two major categories: inorganic and organic. Among them, aqueous organic flow batteries have shown great development potential in the field of energy storage due to their high flexibility, stability, scalability and environmental friendliness. As the core component of flow batteries, the performance of electrolyte materials directly determines the overall performance of the battery. Although traditional electrolyte materials such as viologen and its derivatives have certain applications, their low degree of conjugation and the transition of pyridine ring aromaticity from oxidized state to reduced state limit their application in two-electron storage. Therefore, finding new efficient and stable electrolyte materials has become a hot topic of research.

[0004] Imides, especially naphthalene diimide derivatives, have gradually come into the researchers' field of vision due to their enhanced aromaticity after gaining electrons and their contribution to di-electron stabilization. When used as electrolyte materials for flow batteries, these substances are expected to significantly improve the energy density and cycle stability of batteries. However, the high cost, low efficiency and cumbersome steps of traditional synthesis methods have become bottlenecks for their commercial applications.

[0005] In view of the problems existing in the existing traditional electrolyte materials viologen and its derivatives in energy storage systems such as flow batteries, the low degree of conjugation makes the electron transmission path in the molecule not smooth, thus affecting the electron transmission efficiency; the change in the aromaticity of the pyridine ring causes the material to become structurally unstable during the recycling process, which in turn affects the battery's cycle performance and life, resulting in limited performance in two-electron storage, affecting the stability and cycle performance of the material. Traditional methods for synthesizing imide substances often involve complex reaction steps and expensive raw materials, and the high reaction temperature, long reaction time and high reaction atmosphere requirements lead to high production costs, limiting their commercial application. Summary of the invention

[0006] In view of the technical status quo that existing electrolyte materials have low conjugation degree, poor cycle stability, short life, and existing synthesis methods of imide substances have expensive raw materials, high reaction temperature, long reaction time and high requirements for reaction atmosphere, resulting in complex synthesis process and high synthesis cost, the purpose of the present invention is to provide a class of imidazole-modified imide derivatives, synthesis methods and their applications in liquid flow batteries.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a class of imidazole-modified imide derivatives, wherein the imidazole-modified imide derivative is any one of the following structural formulas: , ,

[0008] Among them, R is , , , , , , , and Any one of the groups; n is an integer from 1 to 10.

[0009] The synthesis method of the above-mentioned imidazole-modified imide derivative comprises: S1, dissolving precursor A and compound 1, reacting, cooling, filtering, washing, and drying to obtain precursor B; S2, in step S1, the precursor B and the compound 2 are dissolved, reacted, filtered, washed, and dried to obtain an imidazole-modified imide derivative; The precursor A is any one of the following structural formulas , , ; The compound 1 is , where n is an integer from 1 to 10; The compound 2 is , , , , , , , or Any one of .

[0010] The molar ratio of the precursor A to the compound 1 is 1:2-4.

[0011] The solvents for dissolving the precursor A and the compound 1 are triethylamine and acetic acid, respectively.

[0012] Furthermore, the volume ratio of triethylamine to acetic acid is 1:40.

[0013] The S1 reaction temperature is 110°C to 130°C, and the reaction time is 22 h to 26 h.

[0014] The solvent used to dissolve the precursor B and the compound 2 is any one of water, N,N-dimethylformamide, dimethyl sulfoxide or toluene.

[0015] Furthermore, the solvent used to dissolve the precursor B and compound 2 is N,N-dimethylformamide.

[0016] The molar ratio of the precursor B to the compound 2 is 1:2-4.

[0017] The S2 reaction temperature is 110°C to 130°C, and the reaction time is 48 h to 72 h.

[0018] The S1 washing is performed by washing with water, ethanol and methanol in sequence; the S2 washing is performed by washing with NN dimethylformamide and acetone in sequence.

[0019] The above-mentioned imidazole-modified imide derivative is used in liquid flow batteries. The imidazole-modified imide derivative is made into a negative electrode electrolyte material in a neutral aqueous organic redox flow battery, and the MiAcNH-TEMPO solution is a positive electrode electrolyte.

[0020] The volume ratio of the positive electrode electrolyte to the negative electrode electrolyte is 1:2.5~3.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a class of imidazole-modified imide derivatives, which successfully achieve a significant improvement in the water solubility of the imide derivatives by introducing multiple water-soluble groups (increased from the traditional two to four or more) and combining the modification strategy of the imidazole derivatives; compared with the viologen derivatives, the imide derivatives of the present invention exhibit more excellent conjugation and aromaticity characteristics. From pyromellitic acid diimide to naphthalene diimide, and then to a series of imide derivatives of perylene diimide, the conjugation effect is gradually enhanced and the molecular band gap is reduced, thereby promoting the rapid transfer of electrons between molecules, and the structural optimization makes its two-electron storage mechanism more efficient and stable; by improving the conjugation and increasing the molecular volume, the imidazole-modified imide derivatives of the present invention not only improve the efficiency of electron transfer, but also significantly improve the stability of the molecule in the redox reaction, providing strong material support for the development of liquid flow battery technology, especially the field of neutral aqueous liquid flow batteries, and successfully solving the technical problems of insufficient conjugation and poor two-electron storage stability commonly existing in current anode electrolyte materials (such as viologen).

[0022] The present invention provides a method for synthesizing an imidazole-modified imide derivative, which can be achieved in only two steps, shortening the reaction time. By modifying the imidazole derivative on the side chain, the hydrogen bond interactions between molecules and between molecules and water are increased, and the molecular size is enlarged while the water solubility of the molecule is improved. The solvent used in the reaction is low in price, the method is simple, the yield is high, and a large amount of synthesis is possible. This innovative achievement has far-reaching significance for promoting the commercial application of clean energy storage technology.

[0023] The innovative application of a class of imidazole-modified imide derivatives as negative electrode electrolytes in the field of flow batteries provided by the present invention marks a major progress in battery technology. The application uses imide derivatives designed by molecular engineering technology as the core component of the negative electrode electrolyte, and matches TEMPO functionalized with imidazole as the positive electrode electrolyte, and selects DSVN membrane as the anion exchange membrane to construct an efficient and stable neutral aqueous organic flow battery system with dual electron storage. With its high solubility in water, wide output voltage range within the range of water electrolysis, extremely low redox potential, and reversible and distinct redox peaks, it exhibits dual electron transfer stability in electrochemical tests. These superior properties provide a solid material foundation for the development of low-cost, high energy density, high power output and long cycle life neutral aqueous organic flow batteries. The present invention has broad application prospects and is suitable for commercial large-scale energy storage systems, which can meet the growing demand for clean energy storage in modern society. This innovation not only promotes the in-depth research and application of imide derivatives in liquid flow battery technology, but also opens up a new path for the future development of the field of neutral aqueous liquid flow batteries. It has immeasurable important value and far-reaching significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a CV curve diagram of the imide derivative NDI-C2-MzMe of the present invention; Figure 2 It is a full-cell CV curve diagram of the imide derivative NDI-C3-MzC2OH / Mi-AcNhTEMPO assembled battery of the present invention; Figure 3 This is an electrochemical test diagram of a battery assembled with the imide derivative NDI-C2-MzMe of the present invention; Figure 4 This is an electrochemical test diagram of a battery assembled with the imide derivative NDI-C3-MzC2OH of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the concept of the present invention and the technical effects produced in combination with the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the present invention. The test methods used in the embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can all be reagents and materials obtained from commercial channels.

[0026] Example 1 This embodiment provides an imidazole-modified imide derivative NDI-C2-MzMe, and the specific synthesis process is as follows: (1) Preparation of precursor B: Precursor A is ; n=1, compound 1 is ; The chemical reaction equation of precursor B is:

[0027] 1.07 g of precursor A, 1.85 g of 2-chloroethylamine hydrochloride and 2 mL of triethylamine were added into a 250 mL pressure tube, and finally 80 ml of acetic acid was added. The mixture was heated to 120 °C and refluxed for 24 h. After the reaction was completed, the mixture was filtered, and the white solid was washed with water: ethanol: methanol in a volume ratio of 1:1:1, and then vacuum dried to obtain precursor B. The structural formula of precursor B is as follows: .

[0028] (2) Synthesis of imide derivative NDI-C2-MzMe: 6 g of precursor B, 5.04 g of N-methylimidazole, and 90 mL of N-N-dimethylformamide solvent were added into a 250 mL pressure tube and reacted at 120 °C for 72 h to obtain a reaction solution. After the reaction was completed, the reaction solution was filtered, and the white solid was washed with N-N-dimethylformamide and acetone in a volume ratio of 1:1, respectively, and then vacuum dried to obtain the final product NDI-C2-MzMe, whose structural formula is as follows: .

[0029] The specific NMR data of the obtained imidazole-modified imide derivative NDI-C2-MzMe are as follows: 1 H NMR (400 MHz, D2O)δ8.84 (s, 2H), 8.65 (s, 4H), 7.52 (s, 2H), 7.37(s, 2H), 4.60 (s, 8H), 3.83 (s, 6H). 13 C NMR (101 MHz, D2O) δ163.66 (s), 136.56 (s), 131.24 (s), 126.03(s), 125.68 (s), 123.76 (s), 122.82 (s), 47.29 (s), 40.53 (s), 35.76(s). It is proved that the above process synthesizes the compound.

[0030] Example 2 This embodiment provides an imidazole-modified imide derivative NDI-C3-MzC2OH, and the specific synthesis process is as follows: (1) Preparation of precursor B: Precursor A is , n=2, compound 1 is ; The chemical reaction equation of precursor B is:

[0031] 1.07 g of precursor A, 2.07 g of 2-chloroethylamine hydrochloride and 2 mL of triethylamine were added into a 250 mL pressure tube, and finally 80 mL of acetic acid was added. The mixture was heated to 120 °C and refluxed for 24 h. After the reaction was completed, the mixture was filtered and the white solid was washed with water: ethanol: methanol in a volume ratio of 1:1:1, and then vacuum dried to obtain precursor B. The structural formula of precursor B is as follows: .

[0032] (2) Synthesis of imide derivative NDI-C3-MzC2OH: Compound 2 is ; 6 g of precursor B, 6.42 g of 1-(2-hydroxyethyl)imidazole, and 90 mL of N-N-dimethylformamide solvent were added into a 250 mL pressure tube and reacted at 120 °C for 72 h to obtain a reaction solution. After the reaction was completed, the reaction solution was filtered, and the white solid was washed with N-N-dimethylformamide and acetone in a volume ratio of 1:1, respectively, and then vacuum dried to obtain the final product NDI-C3-MzC2OH, whose structural formula is as follows: .

[0033] The specific NMR data of the obtained imidazole-modified imide derivative NDI-C3-MzC2OH are as follows: 1 H NMR (400 MHz, D2O)δ8.92 (s, 2H), 8.66 (s, 4H), 7.60 (s, 2H), 7.53(s, 2H), 4.37−4.29 (m, 8H), 4.18 (t, J = 6.9 Hz, 4H), 3.92 (t, 4H), 2.36 (m,4H). 13 C NMR (101 MHz, D2O) δ163.42 (s), 136.10 (s), 130.98 (s), 125.43 (d,J = 15.6 Hz), 122.81 (s), 122.39 (s), 59.72 (s), 51.70 (s), 47.26 (s), 37.53(s), 27.62(s). It is proved that the above process synthesizes the compound.

[0034] Example 3 This embodiment provides an imide derivative PDI-C3-MzDiol, and the specific synthesis process is as follows: (1) Preparation of precursor B Precursor A is , n=2, compound 1 is ; The reaction formula of precursor B is as follows:

[0035] 1.96 g of precursor A, 2.6 g of 2-chloroethylamine hydrochloride and 2 mL of triethylamine were added into a 250 ml pressure tube, and finally 80 mL of acetic acid was added. The mixture was heated to 120 °C and refluxed for 24 h. After the reaction was completed, the mixture was filtered, and the white solid was washed with water: ethanol: methanol in a volume ratio of 1:1:1, and then vacuum dried to obtain precursor B. The structural formula of precursor B is as follows: .

[0036] (2) Synthesis of imide derivative PDI-C3-MzDiol Compound 2 is ; 6 g of precursor B, 6.28 g of 3-(1H-imidazole-1-yl)propane-1,2-diol, and 90 mL of N-N-dimethylformamide solvent were added into a 250 mL pressure tube and reacted at 120 °C for 72 h to obtain a reaction solution. After the reaction was completed, the reaction solution was filtered, and the white solid was washed with N-N-dimethylformamide and acetone in a volume ratio of 1:1, respectively, and then vacuum dried to obtain the final product PDI-C3-MzDiol, whose structural formula is as follows: The structural formula of PDI-C3-MzDiol is shown below:

[0037] Example 4 This embodiment provides the use of the imide derivative modified by imidazole of the present invention as a negative electrode electrolyte material in a liquid flow battery.

[0038] The imidazole-modified imide derivatives NDI-C2-MzMe and NDI-C3-MzC2OH prepared in Example 1 and Example 2 are used as negative electrode electrolyte materials for neutral aqueous organic liquid flow batteries and can be tested by the following steps: Step 1: Assemble the core fixture The neutral aqueous organic redox flow battery used in the test is a single cell structure. The positive terminal plate, positive insulating plate, positive current collector, positive liquid flow frame, positive graphite felt, positive sealing gasket, anion exchange membrane, negative sealing gasket, negative graphite felt, negative liquid flow frame, negative current collector, negative insulating plate, and negative terminal plate are fixed with bolts in both directions in turn, and external pipes are connected to check whether the bolts are loose. If they are loose, they can be reinforced again. Before the test, the water flow tightness and pressure test are carried out. Two liquid storage bottles and a peristaltic pump are connected on the basis of the above-mentioned fixture. After 2 hours of circulation, if there is no leakage and there is no liquid level change in the positive and negative electrode storage bottles, the battery fixture can be retained for standby. If the above-mentioned leaks occur, the above steps need to be repeated until there is no problem.

[0039] Step 2: Preparation of electrolyte materials Prepare a sufficient amount of 2 M NaCl solution in a volumetric flask. The positive electrode electrolyte uses a solution of methylimidazole-modified tetramethylpiperidinium nitroxide (4-amino-2,2,6,6-tetramethylpiperidinium 1-oxyl free radical) with the chemical formula C 15 H 26 N4O2, referred to as MiAcNH-TEMPO.

[0040] (1) Preparation of 0.1 M NDI-C2-MzMe / 0.1 M MiAcNH-TEMPO neutral aqueous organic flow battery Take 330 mg of NDI-C2-MzMe and 495 mg of MiAcNH-TEMPO and dissolve them in 6 mL and 15 mL of 2 M NaCl solution respectively, stir or ultrasonicate to make them completely dissolved, the concentration of both in NaCl solution is 0.1 M; the volume ratio between the two mixed solutions is 1:2.5 to ensure that NDI-C2-MzMe can be fully charged and discharged. Put it in the glove box with argon bubbling for 10 minutes, NDI-C2-MzMe and MiAcNH-TEMPO are used as the negative electrode electrolyte and positive electrode electrolyte of the battery respectively, and the battery composed is called 0.1 M NDI-C2-MzMe / MiAcNH-TEMPO-based AORFB.

[0041] (2) Preparation of 0.1 M NDI-C3-MzC2OH / MiAcNH-TEMPO neutral aqueous organic flow battery Take 386 mg of NDI-C3-MzC2OH and 495 mg of MiAcNH-TEMPO and dissolve them in 6 mL and 15 mL of 2M NaCl solution respectively, stir or ultrasonicate to make them completely dissolved, and the concentration of both in NaCl solution is 0.1 M. The volume ratio between the mixed solution formed by the two is 1:2.5 to ensure that NDI-C3-MzC2OH is fully charged and discharged. Bubble argon for 10 minutes, and the derivative NDI-C3-MzC2OH and MiAcNH-TEMPO are used as the negative electrode electrolyte and positive electrode electrolyte of the battery respectively. The battery composed is called 0.1 M NDI-C3-MzC2OH / MiAcNH-TEMPO-based AORFB.

[0042] Step 3: Assemble the neutral aqueous organic redox flow battery and perform performance testing; (1) Place the fixture prepared in step 1 and the solution prepared in step 2 in an inert gas-protected glove box. Use the prepared NDI-C2-MzMe and NDI-C3-MzC2OH solutions as the negative electrolyte and MiAcNH-TEMPO solution as the positive electrolyte, respectively, to assemble the full battery. Connect the external power supply, peristaltic pump, and Xinwei tester, set the program, and then perform the charge and discharge test.

[0043] (2) After the above steps, the basic test data of the prepared 0.1 M NDI-C2-MzMe / MiAcNH-TEMPO-based AORFB are as follows: double electron storage, voltage range 0.2~1.8 V, current density 40 mA cm -2 After 2400 cycles, the capacity retention rate was 97.22%, and the single-cycle capacity retention rate was 99.7683%. (3) After the above steps, the basic test data of the prepared 0.1 M NDI-C3-MzC2OH / MiAcNH-TEMPO-based AORFB are as follows: double electron storage, voltage range 0.1~1.8 V, current density 40 mA cm -2 After 1800 cycles, the capacity retention rate was 93.20%, and the single-cycle capacity retention rate was 99.3195%. Therefore, the above detailed battery test results have undoubtedly verified the excellent performance of imidazole-modified imide derivatives as negative electrode electrolyte materials in neutral aqueous organic flow battery systems. First, the introduction of imidazole derivatives significantly enhances the hydrogen bonding between imide molecules and water molecules, greatly promoting their solubility in aqueous solution, thus laying a solid foundation for the application of such molecules in neutral aqueous organic flow battery electrolytes. Secondly, the strong conjugation of the imide molecule itself shows a high stability of the molecular skeleton during the double electron transfer process. This stability not only promotes the efficiency of double electron transfer, but also significantly improves the overall stability of the molecule in the redox reaction. It is particularly worth mentioning that the strong conjugation also leads to a decrease in the band gap of the imide molecule, accelerates the migration rate of electrons, and ensures the realization of a stable double electron transfer process. In addition, the larger volume of the imide molecule effectively prevents the penetration of the negative electrode electrolyte through the ion exchange membrane during the charge and discharge cycle, further improving the performance and life of the battery. Compared with the currently widely studied viologen molecules, imide molecules not only show more significant advantages in conjugation and aromaticity, but also can maintain the basic stability of aromaticity during the double electron transfer process. At the same time, with its larger molecular volume, it provides higher electrochemical stability. More importantly, compared with previous research results, by increasing the number of water-soluble groups from two to four, not only the water solubility of the molecule is significantly improved, but also its performance in the electrolyte is further optimized by increasing the molecular size, opening up new possibilities for the development of neutral aqueous organic flow battery technology. In the electrochemical test of double electron transfer, the neutral aqueous organic redox batteries based on 0.1 M NDI-C2-MzMe / MiAcNH-TEMPO and 0.1 MNDI-C3-MzC2OH / MiAcNH-TEMPO showed extremely strong stability. Not only that, some other imidazole derivatives such as: , , and

[0044] (n=1~10) etc. can also be modified to further improve the solubility and expand the molecular volume to obtain better negative electrode electrolyte materials.

[0045] The present invention conducts relevant tests on the imidazole-modified imide derivatives NDI-C2-MzMe and NDI-C3-MzC2OH materials prepared in the above-mentioned Examples 1 and 2. The test results are shown in the attached Figure 1 ~Attached Figure 4 .

[0046] By the attached Figure 1From the data, it can be seen that the imide derivative NDI-C2-MzMe modified by imidazole in Example 1 of the present invention has two redox peaks, located at -0.07 V and -0.41 V respectively. The existence of two redox peaks indicates that the NDI-C2-MzMe molecule can undergo two electron transfers in the electrochemical process, which is of great significance for the application of NDI-C2-MzMe in the field of electrochemistry.

[0047] By the attached Figure 2 The data show that when the imide derivative NDI-C3-MzC2OH of Example 1 of the present invention is used as the negative electrode electrolyte and MiAcNH-TEMPO is used as the positive electrode electrolyte for double electron storage, the voltage windows corresponding to the two electrons are 0.93 V and 1.29 V, respectively. This indicates that the flow battery system with the imide derivative NDI-C3-MzC2OH as the negative electrode electrolyte and MiAcNH-TEMPO as the positive electrode electrolyte has a wide voltage range (0.93 V to 1.29 V), indicating that the system has a high energy density potential.

[0048] By the attached Figure 3 The data show that in the electrochemical test of the neutral aqueous organic flow battery obtained by using 0.1 M imidazole-modified imide derivative NDI-C2-MzMe as the negative electrode electrolyte and 0.1 M MiAcNH-TEMPO as the positive electrode electrolyte, the voltage test range is 0.1 V-1.8 V, and when the current density is 40 mA cm -2 When the concentration is 0.1 M, the neutral aqueous organic flow battery based on NDI-C2-MzMe / MiAcNH-TEMPO shows good cycle stability in 2400 cycles; after 2400 cycles, the capacity retention rate is 97.22%, and the single-cycle capacity retention rate is 99.7683%. The illustrations show the voltage and capacity curves corresponding to the 1st, 1200th, and 2400th cycles, respectively. The voltage range of the battery is 0.1 V-1.8V. As the number of cycles increases, the shape of the voltage and capacity curves of the battery remains basically unchanged, further verifying the good cycle stability of the battery. It can be seen that the neutral aqueous organic flow battery based on NDI-C2-MzMe / MiAcNH-TEMPO shows excellent cycle stability and high capacity retention in electrochemical tests. These performance advantages make the battery have broad application prospects in the field of energy storage.

[0049] By the attached Figure 4The data show that in the electrochemical test of the neutral aqueous organic flow battery obtained by using 0.1 M imidazole-modified imide derivative NDI-C3-MzC2OH as the negative electrode electrolyte and 0.1 M MiAcNH-TEMPO as the positive electrode electrolyte, the voltage test range is 0.1 V-1.8 V, and when the current density is 40 mA cm -2 The neutral aqueous organic flow battery based on 0.1 M NDI-C3-MzC2OH / MiAcNH-TEMPO showed good cycle stability in 1800 cycles; after 1800 cycles, the capacity retention rate was 93.20%, and the single-cycle capacity retention rate was 99.3195%. The illustrations show the voltage and capacity curves corresponding to the 1st, 600th, 1200th, and 1800th cycles, respectively. The voltage range of the battery is 0.1 V-1.8 V. It can be seen that the neutral aqueous organic flow battery based on 0.1 M NDI-C3-MzC2OH / MiAcNH-TEMPO showed excellent cycle stability and high capacity retention in electrochemical tests. These performance advantages make the battery have potential application value in the field of energy storage, especially in situations where long-term stable operation and multiple charge and discharge cycles are required. The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A class of imidazole-modified imide derivatives, characterized in that: The imidazole-modified imide derivative is any one of the following structural formulas: 、 、 Among them, R is , , , , , , , and Any one of the groups; n is an integer from 1 to 10.

2. A method for synthesizing an imidazole-modified imide derivative as claimed in claim 1, characterized in that: include: S1, dissolving precursor A and compound 1, reacting, cooling, filtering, washing, and drying to obtain precursor B; S2, in step S1, the precursor B and the compound 2 are dissolved, reacted, filtered, washed, and dried to obtain an imidazole-modified imide derivative; The precursor A is any one of the following structural formulas 、 、 ； The compound 1 is , where n is an integer from 1 to 10; The compound 2 is , , , , , , , or Any one of .

3. The method for synthesizing a class of imidazole-modified imide derivatives according to claim 2, characterized in that: The molar ratio of the precursor A to the compound 1 is 1:2-4.

4. The method for synthesizing a class of imidazole-modified imide derivatives according to claim 2, characterized in that: The solvents for dissolving the precursor A and compound 1 are triethylamine and acetic acid, respectively. The reaction temperature of S1 is 110°C to 130°C, and the reaction time is 22 h to 26 h.

5. The method for synthesizing a class of imidazole-modified imide derivatives according to claim 2, characterized in that: The solvent used to dissolve the precursor B and the compound 2 is any one of water, N,N-dimethylformamide, dimethyl sulfoxide or toluene.

6. The method for synthesizing an imidazole-modified imide derivative according to claim 2, characterized in that: The molar ratio of the precursor B to the compound 2 is 1:2-4.

7. The method for synthesizing an imidazole-modified imide derivative according to claim 2, characterized in that: The S2 reaction temperature is 110°C to 130°C, and the reaction time is 48 h to 72 h.

8. The method for synthesizing a class of imidazole-modified imide derivatives according to claim 2, characterized in that: The S1 washing is performed by washing with water, ethanol and methanol in sequence; the S2 washing is performed by washing with NN dimethylformamide and acetone in sequence.

9. The use of an imidazole-modified imide derivative in a liquid flow battery according to claim 1, characterized in that: The imidazole-modified imide derivative is prepared as the negative electrode electrolyte material in the neutral aqueous organic redox flow battery, and the MiAcNH-TEMPO solution is the positive electrode electrolyte.

10. The use of an imidazole-modified imide derivative in a liquid flow battery according to claim 9, characterized in that: The volume ratio of the positive electrode electrolyte to the negative electrode electrolyte is 1:2.5~3.

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