A water-soluble organic polymer flow battery negative electrode polymer material and preparation method thereof

Abstract

The present invention belongs to the field of liquid flow batteries, specifically relating to a water-soluble organic polymer liquid flow battery negative electrode polymer material and its preparation method. The negative electrode polymer is synthesized by free radical polymerization of 3-chloro-2-hydroxypropyl methacrylate and 3-sulfonate propyl methacrylate potassium salt, followed by quaternization with a 4,4'-bipyridine monosubstituted derivative. The liquid flow battery system includes the above-mentioned water-soluble negative electrode polymer and a water-soluble positive electrode polymer. Using the polymer as the positive and negative electrode materials can inhibit cross-contamination between electrode materials, improve the battery's cycle stability, and form a low-cost, highly safe, and stable liquid flow battery that meets large-scale energy storage needs.

Description

Technical Field

[0001] The present invention belongs to the field of liquid flow batteries, and in particular relates to a water-soluble organic polymer liquid flow battery negative electrode polymer material and a preparation method thereof. Background Art

[0002] The growth model dominated by non-renewable energy has brought about a dual crisis in energy and the environment. Among the many strategies to solve this problem, the development of clean, environmentally friendly renewable energy strategies is the most promising. However, renewable energy represented by solar and wind energy is usually volatile and intermittent, which poses a considerable challenge to the power system. Developing a supporting large-scale energy storage system is an effective way to solve this problem. Traditional large-scale energy storage methods, such as pumped storage and compressed gas storage, are restricted by the geographical environment. Liquid flow batteries, as a new type of large-scale energy storage technology, have the advantages of large storage capacity and long life. Its unique structural design completely separates the energy storage material from the electrode, with the advantage of independent design of capacity and power, thus meeting energy storage needs from several watt-hours to several megawatt-hours.

[0003] Existing small molecule flow battery systems suffer from severe cross-contamination between the positive and negative electrode solutions, leading to rapid capacity degradation. Using polymers as electrode materials for aqueous flow batteries, increasing the molecular size can effectively suppress cross-contamination and improve battery stability. Summary of the Invention

[0004] The present invention provides a water-soluble organic polymer liquid flow battery negative electrode polymer and a preparation method thereof, wherein the water-soluble negative electrode polymer can be used as a negative electrode liquid flow battery material to obtain a full polymer liquid flow battery with good stability.

[0005] The chemical structural formula of the water-soluble negative electrode polymer of the present invention is:

[0006] Among them, x=30-40, y=30-40, z=20-40.

[0007] The preparation method of the above-mentioned water-soluble negative electrode polymer is as follows: using monomers 3-chloro-2-hydroxypropyl methacrylate and monomers 3-sulfonate propyl methacrylate potassium salt as raw materials, adding an initiator, first performing a free radical polymerization reaction, and then reacting with a monosubstituted 4,4'-bipyridine derivative to undergo a quaternization reaction to synthesize the water-soluble negative electrode polymer. Taking 1-propanesulfonic acid-4,4'-bipyridine as an example, its chemical reaction formula is shown in Formula (1):

[0008]

[0009] The specific preparation method of the water-soluble negative electrode polymer includes the following steps:

[0010] S11. Add 3-chloro-2-hydroxypropyl methacrylate, 3-sulfopropyl methacrylate potassium salt, and an appropriate amount of solvent to a container in sequence. After all the solids are dissolved, add an initiator and stir to deoxygenate under a nitrogen atmosphere (70-120°C) for 6-20 hours. After the reaction is complete, cool to room temperature and dialyze using a cellulose dialysis membrane. After dialysis, freeze-dry the solution to obtain a white flocculent polymer.

[0011] The initiator in step S11 is one of azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutylamidine dihydrochloride, α-ketoglutaric acid, and potassium persulfate.

[0012] The molar ratio of the monomer 3-chloro-2-hydroxypropyl methacrylate to the monomer 3-sulfonic acid propyl methacrylate potassium salt is 1:1 to 1:5.

[0013] The mass percentage of the monomer 3-chloro-2-hydroxypropyl methacrylate in the solvent is 30% to 45%, and the mass percentage of the monomer 3-sulfonic acid propyl methacrylate potassium salt in the solvent is 20% to 40%.

[0014] The solvent is one of deionized water, acetonitrile, N,N-dimethylformamide, toluene, and ethanol;

[0015] The molecular weight cut-off of the cellulose dialysis membrane used is 300 to 14,000.

[0016] S12. Dissolve the white flocculent polymer in deionized water, add an appropriate amount of a 4,4'-bipyridine monosubstituted derivative, react at 60-80°C for 2-14 days, dialyze using a cellulose dialysis membrane, and freeze-dry the solution after dialysis to obtain a yellow solid.

[0017] The 4,4'-bipyridine monosubstituted derivative in step S12 is one of 1-methyl-4,4'-bipyridine, 1-propanesulfonic acid-4,4'-bipyridine, 1-amino-4,4'-bipyridine, and 1-ethoxy-4,4'-bipyridine;

[0018] The mass percentage of the 4,4'-bipyridine monosubstituted derivative in deionized water is 5% to 30%.

[0019] The present invention also provides an all-polymer liquid flow battery system, comprising a positive electrode polymer material and a negative electrode polymer material, wherein the negative electrode polymer material is the above-mentioned water-soluble negative electrode polymer, and the chemical structure of the positive electrode polymer material is:

[0020]

[0021] The polymer flow battery system also includes: two electrolyte reservoirs, the two electrolyte reservoirs are arranged at intervals, each of the electrolyte reservoirs is a storage tank for storing electrolyte or a salt cave with a physical dissolution cavity formed after salt mining, the electrolyte in one electrolyte reservoir contains the positive electrode battery material and the supporting electrolyte, and the electrolyte in the other electrolyte reservoir contains the negative electrode battery material and the supporting electrolyte, the positive electrode battery material and the negative electrode battery material are respectively directly dissolved or dispersed in a system with water as a solvent in the form of a bulk; a liquid flow battery stack, the liquid flow battery stack includes a battery separator, the battery separator separates the liquid flow battery stack into an anode area and a cathode area that are spaced apart, the anode area is connected to one electrolyte reservoir, and the cathode area is connected to the other electrolyte reservoir.

[0022] The concentrations of the positive electrode battery material and the negative electrode battery material are both 0.2 mol·L -1 ~3.5 mol·L -1 .

[0023] The electrolyte reservoir is a pressurized sealed container with a pressure of 0.1MPa to 0.8MPa.

[0024] Inert gas is introduced into the electrolyte reservoir for purging and maintaining pressure, wherein the inert gas is nitrogen or argon.

[0025] The battery separator is an anion exchange membrane, a cation exchange membrane or a porous membrane.

[0026] The supporting electrolyte is at least one of NaCl salt solution, KCl salt solution, Na2SO4 salt solution, K2SO4 salt solution, MgCl2 salt solution, MgSO4 salt solution, CaCl2 salt solution, and NH4Cl salt solution. The molar concentration of the supporting electrolyte is 1.0 mol·L -1 ~5.0 mol·L -1 .

[0027] Electrodes are provided in the anode region and the cathode region, respectively, and the positive and negative electrodes are carbon material electrodes, wherein the carbon material electrodes are one or a composite of carbon felt, carbon paper, carbon cloth, carbon black, activated carbon fiber, activated carbon particles, graphene, graphite felt, and glassy carbon materials.

[0028] The electrode is formed as an electrode plate, and the thickness of the electrode plate is 5 mm to 10 mm.

[0029] The polymer flow battery system further includes: current collectors, which are respectively arranged on both sides of the flow battery stack. The current collectors can collect the current generated by the battery materials of the flow battery stack and conduct it to external wires.

[0030] The current collector is a conductive metal plate, a graphite plate or a carbon-plastic composite plate.

[0031] The conductive metal plate includes at least one metal selected from the group consisting of copper, nickel, and aluminum.

[0032] The beneficial effects of the present invention are as follows: with the negative electrode active group (Viologen) as the main body, 3-sulfopropyl methacrylate potassium salt containing a hydrophilic group is introduced to prepare it into a macromolecular polymer, and the sulfonic acid group connected to the polymer is used to increase its own solubility; by designing and introducing a water-soluble negative electrode polymer with excellent electrochemical activity and a positive electrode polymer as a redox couple, a full-polymer liquid flow battery with good stability is obtained; using the water-soluble negative electrode polymer as the electrode material, the increase in molecular weight can effectively reduce cross-contamination between active substances, reduce the decline in battery capacity, and improve the stability of the battery, thereby obtaining a liquid flow battery with the advantages of easy preparation of active materials and stable charge and discharge performance, etc., which can meet the needs of large-scale energy storage.

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of an all-polymer flow battery system according to an embodiment of the present invention;

[0035] Figure 2 is a hydrogen nuclear magnetic spectrum of the water-soluble negative electrode polymer in D2O solvent according to Example 1 of the present invention;

[0036] Figure 3 1 is the solubility curve of the water-soluble negative electrode polymer of Example 1 of the present invention in sodium chloride solutions of different concentrations;

[0037] Figure 4 The water-soluble negative electrode polymer of Example 1 of the present invention (concentration of 3 mg mL -1 , in a sodium chloride aqueous solution at pH = 7) at a scan rate of 10 mV / s;

[0038] Figure 5 This is a cycle stability diagram of a flow battery system using the water-soluble negative electrode polymer of Example 1 of the present invention as the negative electrode material and the TEMPO polymer as the positive electrode material;

[0039] Figure 6 The charge and discharge performance of a flow battery system using the water-soluble negative electrode polymer of Example 1 of the present invention as the battery material and 4-OH TEMPO as the positive electrode battery material at different currents;

[0040] Reference numerals:

[0041] All-polymer flow battery system 100;

[0042] an electrolyte reservoir 10;

[0043] Liquid flow battery stack 20; electrode plate 21; positive electrode electrolyte 22; negative electrode electrolyte 23; battery separator 24; circulation pipeline 25; circulation pump 26; current collector 27. DETAILED DESCRIPTION

[0044] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0045] The negative electrode battery material of the polymer flow battery system 100 is the above-mentioned water-soluble negative electrode polymer, and the positive electrode battery material is a TEMPO polymer containing a 2,2,6,6-tetramethylpiperidin-1-oxyl free radical (TEMPO) group, that is, it has a positive electrode active group 2,2,6,6-tetramethylpiperidin-1-oxyl free radical (TEMPO) and a negative electrode active group (Viologen).

[0046] The chemical structure of TEMPO polymer is:

[0047]

[0048] like Figure 1 As shown, the all-polymer liquid flow battery system 100 according to an embodiment of the present invention includes: two electrolyte reservoirs 10 and a liquid flow battery stack 20, the two electrolyte reservoirs 10 are arranged at intervals, each electrolyte reservoir 10 is a storage tank for storing electrolyte or a salt cave with a physical dissolution cavity formed after salt mining, the electrolyte in one electrolyte reservoir 10 contains positive electrode battery materials and supporting electrolytes, and the electrolyte in the other electrolyte reservoir 10 contains the negative electrode battery materials and supporting electrolytes, the positive electrode battery materials and the negative electrode battery materials are directly dissolved or dispersed in a system with water as a solvent in the form of a bulk, respectively, the liquid flow battery stack 20 includes a battery separator 24, the battery separator 24 separates the liquid flow battery stack 20 into an anode area and a cathode area that are spaced apart and distributed, the anode area is connected to one electrolyte reservoir 10, and the cathode area is connected to the other electrolyte reservoir 10. The introduction of macromolecular active substances with positive electrode active groups (TEMPO) and macromolecular active substances with negative electrode active groups (Viologen) into organic polymers can not only effectively prevent the capacity attenuation problem caused by cross-contamination between ions.

[0049] The following describes an aqueous positive electrode polymer, a preparation method thereof, and a small molecule flow battery system according to embodiments of the present invention with reference to the accompanying drawings.

[0050] In the cyclic voltammetry test, the CH series electrochemical workstation of Shanghai Chenhua Company was used, and the electrochemical properties of the Viologen functionalized water-soluble polymer were tested using a three-electrode system. The working electrode was a glassy carbon electrode (Shanghai Chenhua Company), the reference electrode was an Ag / AgCl electrode, and the counter electrode was a platinum electrode. The scanning range was -0.2V to -0.8V.

[0051] Example 1

[0052] Preparation of a water-soluble negative electrode polymer by free radical polymerization

[0053] To a 250 mL flask with a branched tube, add 3-chloro-2-hydroxypropyl methacrylate (8.93 g, 50 mmol) and 3-sulfopropyl methacrylate potassium salt (24.632 g, 100 mmol). Acetonitrile (40 mL) and ethanol (40 mL) were used as solvents. Azobisisobutyronitrile (AIBN, 0.697 g, 4.25 mmol) was added as the initiator. After purging with N2 for 30 minutes, the mixture was heated to 80°C and allowed to react for 12 hours. Acetone precipitation afforded a white, viscous solid.

[0054] Dissolve the polymer product from the previous step in 100 mL of deionized water. Add 1-sulfonato-4,4'-bipyridine (20.65 g, 100 mmol) and heat to 80°C for 2 days. During the reaction, the solution changes from light yellow to dark yellow. Dialyze using a 300 molecular weight cutoff membrane and lyophilize. A light yellow solid is obtained with a yield of 95%.

[0055] Figure 2 is the H NMR spectrum of the water-soluble negative electrode polymer prepared in Example 1 in D2O solvent;

[0056] Figure 3 1 is the solubility curve of the water-soluble negative electrode polymer prepared in Example 1 in sodium chloride solutions of different concentrations.

[0057] Example 2

[0058] To a 250 mL flask with a branched tube, add 3-chloro-2-hydroxypropyl methacrylate (8.93 g, 50 mmol) and 3-sulfopropyl methacrylate potassium salt (18.474 g, 75 mmol). 40 mL of toluene and 40 mL of acetonitrile were used as solvents. The initiator, 4,4'-azobis(4-cyanovaleric acid) (ABVCA, 1.120 g, 4 mmol), was added. After purging with N2 for 30 minutes, the mixture was heated to 90°C and allowed to react for 7 hours. Acetone precipitation afforded a white, viscous solid.

[0059] The polymer product from the previous step was dissolved in 100 mL of deionized water. 1-Amino-4,4'-bipyridine (20.55 g, 100 mmol) was added and heated to 75°C for 4 days. During the reaction, the solution changed from light yellow to dark yellow. Dialysis was performed using a 700 molecular weight cutoff membrane and lyophilized. A light yellow solid was obtained with a yield of 94%.

[0060] Example 3

[0061] To a 250 mL flask with a branched tube, add 3-chloro-2-hydroxypropyl methacrylate (8.93 g, 50 mmol) and 3-sulfopropyl methacrylate potassium salt (36.948 g, 150 mmol). Deionized water (40 mL) and ethanol (40 mL) were used as solvents. The initiator, 4,4'-azobis(4-cyanovaleric acid) (ABVCA, 1.120 g, 4 mmol), was added. After purging with nitrogen for 30 minutes, the mixture was heated to 80°C and allowed to react for 12 hours. Acetone precipitation afforded a white, viscous solid.

[0062] The polymer product from the previous step was dissolved in 100 mL of deionized water. 1-Ethoxy-4,4'-bipyridine (23.10 g, 100 mmol) was added and heated to 70°C for 4 days. During the reaction, the solution changed from light yellow to dark yellow. Dialysis was performed using a 5000 molecular weight cutoff membrane and lyophilized. A light yellow solid was obtained with a yield of 96%.

[0063] Example 4

[0064] To a 250 mL flask with a branched tube, add 3-chloro-2-hydroxypropyl methacrylate (8.93 g, 50 mmol) and 3-sulfopropyl methacrylate potassium salt (36.948 g, 150 mmol). 40 mL of N,N-dimethylformamide and 40 mL of ethanol were used as solvents. α-ketoglutaric acid (0.730 g, 5 mmol) was added as an initiator. After purging with N2 for 30 minutes, the mixture was heated to 120°C and allowed to react for 12 hours. Acetone precipitation yielded a white, viscous solid.

[0065] Dissolve the polymer product from the previous step in 100 mL of deionized water. Add 1-methyl-4,4'-bipyridine (27.20 g, 100 mmol) and heat to 60°C for 3 days. During the reaction, the solution changes from light yellow to dark yellow. Dialyze the solution using a dialysis membrane with a molecular weight cutoff of 8000 and lyophilize. A light yellow solid is obtained with a yield of 94%.

[0066] Example 5

[0067] To a 250 mL flask with a branched tube, add 3-chloro-2-hydroxypropyl methacrylate (8.93 g, 50 mmol) and 3-sulfopropyl methacrylate potassium salt (24.632 g, 100 mmol). 40 mL of N,N-dimethylformamide and 40 mL of toluene were used as solvents. The initiator, 2,2'-azobisisobutylamidine dihydrochloride (1.62 g, 6 mmol), was added. After purging with N2 for 30 minutes, the mixture was heated to 70°C and allowed to react for 8 hours. Acetone precipitation yielded a white, viscous solid.

[0068] The polymer product from the previous step was dissolved in 100 mL of deionized water. 1-Methyl-4,4'-bipyridine (20.65 g, 100 mmol) was added and heated to 80°C for 14 days. During the reaction, the solution changed from light yellow to dark yellow. Dialysis was performed using a 14,000 molecular weight cutoff membrane and lyophilized. A light yellow solid was obtained with a yield of 95%.

[0069] Electrochemical performance testing

[0070] The electrical properties of the water-soluble negative electrode polymer in Example 1 of the present invention (concentration of 5 mg / mL, in a sodium chloride aqueous solution at pH=7) were studied by cyclic voltammetry (CV) at a scan rate of 10 mV / s. Figure 4 The CV curve of the water-soluble negative electrode polymer in Example 1 of the present invention shows a reduction peak at around -0.647 V and an oxidation peak at around -0.564 V.

[0071] Application examples of all-polymer flow battery systems

[0072] A mixed solution of 100 mg / mL of the water-soluble negative electrode polymer of Example 1 and 1.5 M NaCl was added to the negative electrode electrolyte tank 23 on the left, and a mixed solution of 100 mg / mL of the aqueous positive electrode polymer (TEMPO polymer) and 1.5 M NaCl was added to the positive electrode electrolyte tank 22 on the right. A porous separator (3.5*3*0.45 cm) was used as the separator to form a full polymer flow battery system. During the test, the battery was first set to stand for 10 minutes, and then a constant current charge (current 100 mA, voltage ≤ 1.75 V) and constant current discharge (current 100 mA, voltage ≥ 0.3 V) cycle test was performed 200 times before the test was terminated. Figure 5 This is the cycle stability diagram of the battery. Due to the increase in the solubility of the water-soluble negative electrode polymer, Figure 5 The theoretical capacity of the flow battery assembled in the experiment was also increased to 15Ah / L, and the discharge capacity of the battery was 57% of the theoretical value. After 200 cycles, the average single-cycle capacity decay was 0.12%.

[0073] The charge and discharge tests show that the cycle stability of the water-soluble all-polymer flow battery is improved by using the water-soluble negative electrode polymer and the TEMPO-type positive electrode polymer of the present invention as battery materials.

[0074] Application examples of polymer-small molecule flow battery systems

[0075] A mixed solution of 30 mg / mL of the water-soluble negative electrode polymer in Example 1 of the present invention and 1.5 M NaSO4 was added to the negative electrode electrolyte 23 tank on the left, and a mixed solution of 30 mg / mL of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical (4-OH-TEMPO) and 1.5 M NaSO4 was added to the positive electrode electrolyte 22 tank on the right. The separator adopts an anion exchange membrane (3.5*3*0.45 cm) to form a polymer-small molecule liquid flow battery system. During the test, it is first set to stand for 10 minutes, constant current charge (current setting 20-150 mA, voltage ≤ 1.75 V) and constant current discharge (current 20-150 mA, voltage ≥ 0.3 V), each current density cycle test 5 times, and finally the test is ended. Figure 6 The figure below shows the cycling stability of the battery. Due to the good electrochemical stability of the water-soluble negative electrode polymer, the discharge capacity of the battery remains above 60% of the theoretical value when the current is gradually increased from 20mA to 150mA.

[0076] According to an embodiment of the present invention, the all-polymer liquid flow battery system 100 adopts a device that combines two electrolyte reservoirs 10 and a liquid flow battery stack 20. The liquid flow battery stack 20 adopts a device that combines two electrode plates 21, an electrolytic cell body, a battery separator 24, a circulation pipeline 25, a circulation pump 26, and a current collector 27, and adopts a water-soluble negative electrode polymer and a TEMPO-type positive electrode polymer as the negative electrode battery material and the positive electrode battery material, respectively. The all-polymer liquid flow battery system 100 has the advantages of easy preparation of active materials and stable charge and discharge performance, and meets the needs of large-scale energy storage.

[0077] In summary, the water-soluble negative electrode polymer of the present invention is based on the negative electrode active group (Viologen), which is prepared into a macromolecular polymer by first polymerizing and then quaternizing. It has the following significant advantages: 1. The two groups of sulfonic acid groups connected to the polymer are used to increase its solubility, thereby further improving the energy density of the battery; 2. Using the water-soluble negative electrode polymer as the electrode material, the increase in molecular weight can effectively reduce the cross-contamination between active substances and reduce the decline in battery capacity; 3. When the positive electrode material and the negative electrode material are both polymer materials, the battery separator 24 can directly use a low-cost porous separator (no anion membrane or cationic membrane is required), which can greatly reduce the cost of the flow battery. The small all-polymer liquid flow battery system 100 of the present invention introduces a water-soluble negative electrode polymer with excellent electrochemical activity and a TEMPO-type positive electrode polymer as a redox couple by design, thereby obtaining a stable all-polymer liquid flow battery that meets large-scale energy storage needs.

[0078] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A water-soluble organic polymer flow battery negative electrode polymer material, characterized in that: The chemical structural formula of the negative electrode polymer is: ； The preparation method of the water-soluble organic polymer liquid flow battery negative electrode polymer material is as follows: using monomers 3-chloro-2-hydroxypropyl methacrylate and monomers 3-sulfonic acid propyl methacrylate potassium salt as raw materials, adding an initiator, first performing a free radical polymerization reaction, and then performing a quaternization reaction with a 4,4'-bipyridine monosubstituted derivative to obtain the water-soluble negative electrode polymer.

2. The negative electrode polymer material for a water-soluble organic polymer flow battery according to claim 1, wherein: The preparation method of the polymer material comprises the following steps: S11. In a container, 3-chloro-2-hydroxypropyl methacrylate, 3-sulfopropyl methacrylate potassium salt, and a solvent are added in sequence. After all the solids are dissolved, an initiator is added, and a deoxygenation reaction is carried out by stirring and heating under a nitrogen environment. After the reaction is completed, the mixture is cooled to room temperature; dialyzed using a cellulose dialysis membrane, and after the dialysis is completed, the solution is freeze-dried to obtain a white flocculent polymer. S12. Dissolve the white flocculent polymer in deionized water, add a 4,4'-bipyridine monosubstituted derivative, heat and react for 2-14 days, dialyze using a cellulose dialysis membrane, and freeze-dry the solution after dialysis to obtain a yellow solid.

3. The negative electrode polymer material for a water-soluble organic polymer flow battery according to claim 2, wherein: The initiator in step S11 is one of azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobisisobutylamidine dihydrochloride, α-ketoglutaric acid, and potassium persulfate; the solvent is one of deionized water, acetonitrile, N,N-dimethylformamide, toluene, and ethanol; and the molecular weight cutoff of the cellulose dialysis membrane used is between 300 and 14,000.

4. The negative electrode polymer material for a water-soluble organic polymer flow battery according to claim 2, wherein: In step S11, the molar ratio of the monomer 3-chloro-2-hydroxypropyl methacrylate to the monomer 3-sulfonate propyl methacrylate potassium salt is 1:1 to 1:5; the mass percentage of 3-chloro-2-hydroxypropyl methacrylate in the solvent is 30% to 45%, and the mass percentage of the monomer 3-sulfonate propyl methacrylate potassium salt in the solvent is 20% to 40%.

5. The negative electrode polymer material for a water-soluble organic polymer flow battery according to claim 2, wherein: The heating and deoxygenation temperature in step S11 is 70-120° C., and the reaction time is 6-20 hours.

6. The negative electrode polymer material for a water-soluble organic polymer flow battery according to claim 2, wherein: The 4,4'-bipyridine monosubstituted derivative in step S12 is one of 1-methyl-4,4'-bipyridine, 1-propanesulfonic acid-4,4'-bipyridine, 1-amino-4,4'-bipyridine, and 1-ethoxy-4,4'-bipyridine; the mass percentage of the 4,4'-bipyridine monosubstituted derivative is 5% to 30%; and the heating reaction temperature is 60 to 80°C.

7. An application of the water-soluble organic polymer flow battery negative electrode polymer material as claimed in claim 1, characterized in that: The negative electrode polymer material is used as the negative electrode material of an all-polymer liquid flow battery or a small molecule liquid flow battery.

8. The use of the water-soluble organic polymer flow battery negative electrode polymer material according to claim 7, characterized in that: The chemical structural formula of the positive electrode polymer material of the all-polymer liquid flow battery is: 。

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