An electrochemically etched porous graphite felt electrode material and a flow battery prepared therefrom

Abstract

The present invention relates to an electrochemically etched porous graphite felt electrode material and a flow battery prepared therefrom. The hydrophilicity of the graphite felt is changed by electrochemically pre-treating the graphite felt. After the treated graphite felt is cleaned and dried, the dried graphite felt is placed in an electrolyte solution for electrochemical etching, introducing an irregular pit structure on the surface and inside of the carbon fiber of the graphite felt electrode material. Then, the etched graphite felt electrode is taken out, ultrasonically cleaned with deionized water and dried, and thus the electrochemically etched porous graphite felt electrode material is obtained. The present invention uses an electrochemical treatment method to etch the graphite felt electrode material. By using the graphite felt as an electrode and immersing it in a specific electrolyte to undergo an electrochemical oxidation-reduction reaction, pits are etched on the surface of the graphite felt fibers, the internal structure is changed, the porosity, surface wettability and electrochemical activity are increased, and the performance of the organic aqueous flow battery is enhanced. The process is simple and has high industrial practicability.

Description

Technical Field

[0001] The present invention relates to the technical field of flow batteries, and particularly to an electrochemically etched porous graphite felt electrode material and a flow battery prepared by using the porous graphite felt electrode material. Background Art

[0002] With the utilization of fossil resources, problems such as environmental and energy shortages have become increasingly serious, which has promoted the vigorous development of a series of clean energies such as wind energy and solar energy. However, due to the discontinuous and unstable characteristics of these renewable energies, their storage and utilization are restricted. Therefore, it is necessary to vigorously develop energy storage technologies to solve the instability in the power grid. The flow battery energy storage technology stands out among various energy storage technologies due to its advantages such as large capacity, high safety, and low cost, and has become the first choice for large-scale energy storage technologies. Among them, due to problems such as toxic electrolytes and strong acid and strong corrosion in some metal-based flow batteries, their wide application has been greatly restricted.

[0003] Compared with traditional metal-based flow batteries, organic aqueous flow batteries have many technical advantages and represent a new generation of flow battery technology for grid storage applications. Using water as a solvent, organic active substances are directly dissolved in deionized water, which has low cost, high safety, and is not easy to volatilize, and is considered to be one of the most promising applications in flow batteries. Most of the electrode materials reported in the current literature are graphite felt, which has advantages such as good conductivity and high electrochemical stability. However, its poor hydrophilicity and electrochemical activity restrict its further development. Especially, the electrochemical activity of the graphite felt electrode will decrease after multiple cycles of use, resulting in a decline in the overall performance of the battery. Therefore, it is necessary to modify the performance of the graphite felt electrode to improve its electrochemical activity and stability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: In order to overcome the deficiencies in the prior art, the present invention provides an electrochemically etched porous graphite felt electrode material and a flow battery prepared therefrom. The graphite felt electrode material is modified by an electrochemical method to obtain an electrode with high porosity, high specific surface area, and stability, and the performance of the organic aqueous flow battery is enhanced.

[0005] The technical solution adopted by the present invention to solve its technical problems is: An electrochemically etched porous graphite felt electrode material, characterized by the following steps:

[0006] Step 1: Prepare a mixed solution of N,N-dimethylformamide and (NH4)2SO4 as the electrolyte, and stir it evenly at a constant temperature with a magnetic stirrer;

[0007] Step 2: Conduct an electrochemical pretreatment experiment with a graphite felt as the positive electrode and a graphite felt as the negative electrode. After completion, ultrasonically rinse with deionized water, dry, and take the positive graphite felt for the electrochemical etching experiment;

[0008] Step 3: Add graphene oxide to the measured N,N-dimethylformamide and ultrasonically pulverize it with a high-power ultrasonic disperser for use as the electrochemical etching electrolyte solution;

[0009] Step 4: Use the pretreated graphite felt as the positive electrode and the pretreated graphite felt as the negative electrode. Apply a voltage across the positive and negative electrodes to conduct the electrochemical etching experiment. After the electrochemical etching is completed, ultrasonically rinse with deionized water, dry, and take the negative graphite felt;

[0010] Preferably, in Step 1, 0.6607 g to 3.9642 g of (NH4)2SO4 is weighed with a balance and added to 100 mL of deionized water; 100 to 200 mL of N,N-dimethylformamide is measured and added to the (NH4)2SO4 solution; the constant stirring temperature of the magnetic stirrer is 60 to 80 °C.

[0011] Preferably, in Step 2, the distance between the positive and negative electrodes is 2 to 5 cm, the voltage applied across the positive and negative electrodes is 5 to 10 V, and the pretreatment time is 10 to 40 min.

[0012] Preferably, in Step 3, the mass of the graphene oxide is 0.01 g to 0.03 g, 200 mL of N,N-dimethylformamide is measured; the power of the high-power ultrasonic disperser is 10 to 20%, and the pulverization time is 10 to 30 min.

[0013] Preferably, in Step 4, the distance between the positive and negative electrodes in the electrochemical etching experiment is 1 to 4 cm, the voltage applied across the positive and negative electrodes is 3 to 10 V; the electrochemical etching treatment time is 30 to 90 min.

[0014] As can be seen from the above, the technical route of the present invention is as follows: By electrochemically pretreating the graphite felt, its hydrophilicity is changed, which is beneficial to the diffusion of reactant molecules on the electrode surface. The treated graphite felt is cleaned and dried, and the dried graphite felt is placed in the electrolyte solution for electrochemical etching to introduce an irregular pit structure on the surface and inside of the carbon fiber of the graphite felt electrode material. Then, the etched graphite felt electrode is taken out, ultrasonically cleaned with deionized water, and dried to obtain the porous graphite felt electrode material by electrochemical etching.

[0015] The present invention uses an electrochemical treatment method to etch a graphite felt electrode material. The electrochemical treatment method mainly uses the graphite felt as an electrode and immerses it in a specific electrolyte solution to carry out an electrochemical oxidation-reduction reaction, etching pits on the surface of the graphite felt fibers, changing the internal structure, increasing the porosity, increasing the surface wettability and electrochemical activity. Moreover, graphene oxide is added to the electrolyte in the present invention. On the one hand, it enhances the conductivity in the solution. On the other hand, a small amount of graphene oxide adheres to the surface of the graphite felt electrode, changing the conductive property of the graphite felt electrode, which is beneficial to the appearance of etching pits on the surface and inside of the carbon fiber during the electrochemical treatment process, enabling the modification treatment of the electrode material to extend to a three-dimensional space. At the same time, oxygen-containing functional groups are introduced at the defects, greatly increasing the porosity and specific surface area of the electrode and enhancing the electrochemical activity of the electrode. Moreover, the etching process can be effectively controlled by changing the voltage, time and electrolyte concentration of the electrochemical etching. Compared with the nanoparticle modification method, the modified electrode prepared by this method is more reliable and has higher stability. The modification treatment method of the electrode of the present invention has a simple process, high treatment efficiency, and the prepared organic aqueous phase flow battery material has better electrochemical activity and stable performance.

[0016] An electrode for an organic flow battery, which is prepared from the porous graphite felt electrode material obtained by the above-mentioned electrochemical etching method.

[0017] The present invention provides an organic flow battery, comprising:

[0018] An electrolytic cell tank filled with an electrolyte solution in the electrolytic cell tank, and the electrolyte solution includes a supporting electrolyte;

[0019] Two electrodes, which are arranged opposite to each other, and one of the two electrodes is the electrode for the organic flow battery prepared above;

[0020] A battery separator located in the electrolytic cell tank and dividing the electrolytic cell tank into an anode region communicated with one electrolyte reservoir and a cathode region communicated with another electrolyte reservoir. One of the electrodes is arranged in the anode region and the other electrode is arranged in the cathode region. The anode region has a positive electrode electrolyte containing a positive electrode organic active substance, and the cathode region has a negative electrode electrolyte containing a negative electrode organic active substance; the battery separator allows the supporting electrolyte to penetrate and prevents the positive electrode organic active substance and the negative electrode organic active substance from penetrating, and the positive electrode organic active substance and / or the negative electrode organic active substance is an organic active molecule;

[0021] A circulation pipeline that inputs or outputs the electrolyte in one of the electrolyte reservoirs to or from the anode region and inputs or outputs the electrolyte in the other electrolyte reservoir to or from the cathode region;

[0022] A circulation pump is provided on the circulation pipeline to make the electrolyte circulate.

[0023] Preferably, the battery separator is an anion exchange membrane.

[0024] Preferably, the thickness of the battery separator is 1 μm to 5 mm.

[0025] According to the above organic flow battery, the present invention also provides a flow battery energy storage system based on a salt cavern. The energy storage system includes the above organic flow battery and further includes: two electrolyte storage reservoirs, which are arranged opposite to each other at intervals. The electrolyte storage reservoir is a salt cavern with a physical dissolution cavity formed after salt mining. The physical dissolution cavity stores the electrolyte. The electrolyte includes a positive electrode active material, a negative electrode active material, and a supporting electrolyte. Under the protection of an inert gas environment, the oxidized positive electrode active material and the reduced negative electrode active material are prevented from being oxidized. The organic flow battery is respectively connected to the two electrolyte storage reservoirs.

[0026] The beneficial effects of the present invention are as follows: The present invention has the following advantages:

[0027] (1). The electrochemical treatment method used in the present invention changes the internal structure of the graphite felt electrode material, increases the porosity and specific surface area, and introduces oxygen-containing functional groups at the defects, greatly improving the electrochemical activity of the electrode material.

[0028] (2). The present invention uses an electrolyte added with graphene oxide to perform electrochemical treatment on the graphite felt electrode material, which is beneficial to etching pits on the surface and inside of the carbon fiber, improving the etching efficiency and making the etching process more controllable.

[0029] (3). The electrochemical treatment method used in the present invention has a simple process and is controllable. It can effectively regulate the number and size of pits on the surface and inside of the graphite felt electrode material, and is easy to be popularized industrially.

[0030] (4). The porous graphite felt electrode material prepared by the present invention is beneficial to further combine with nanoparticles with higher catalytic activity, confine the nanoparticles in the porous carbon fiber, and design a graphite felt electrode material with rich hierarchical voids and high specific surface area. Description of the Drawings

[0031] The present invention will be further described below with reference to the drawings and embodiments.

[0032] Figure 1 SEM image of the surface of the graphite felt electrode electrochemically etched for the organic flow battery in Example 1.

[0033] Figure 2It is the voltammetric cycle test diagram of the graphite felt electrode electrochemically etched for the organic flow battery in Example 1.

[0034] Figure 3 It is the efficiency comparison diagram of the three-dimensional porous MnO2 modified graphite felt electrode and the untreated graphite felt electrode in the organic aqueous phase flow battery in Example 1.

[0035] Figure 4 It is the structural schematic diagram of the organic flow battery described in the present invention.

[0036] Figure 5 It is the structural schematic diagram of the flow battery energy storage system based on salt caverns described in the present invention. Detailed implementation manners

[0037] Example 1

[0038] First, weigh 2.6428 g of (NH4)2SO4 with a balance, add it to a 250 mL beaker containing 100 mL of deionized water, measure 100 mL of DMF (N,N-dimethylformamide) with a measuring cylinder and place it in the above solution, and stir evenly at a constant temperature of 60 °C with a magnetic stirrer;

[0039] Use the stirred solution as the electrolyte solution for the electrochemical pretreatment experiment. One graphite felt is used as the positive electrode and the other graphite felt is used as the negative electrode. The distance between the positive and negative electrodes is 2 cm. Apply a voltage of 10 V at both ends of the electrodes, and the reaction time is 20 min; after the electrochemical pretreatment is completed, ultrasonically rinse with deionized water and dry to obtain the positive graphite felt.

[0040] Weigh 0.03 g of graphene oxide with a balance, add it to 200 mL of DMF, and ultrasonically pulverize it with a high-power ultrasonic disperser at a power of 10% for 30 min. The pulverized solution is used as the electrolyte solution for the electrochemical etching experiment.

[0041] Use the pretreated graphite felt as the positive electrode and the pretreated graphite felt as the negative electrode. The distance between the positive and negative electrodes is 1 cm. Apply a voltage of 3 V at both ends of the electrodes, and the reaction time for electrochemical etching is 30 min. After the electrochemical etching is completed, ultrasonically rinse with deionized water and dry to obtain the negative graphite felt. As Figure 1 shown, irregular pits appear on the surface and inside of the modified graphite felt.

[0042] Test the cyclic voltammetry characteristics of the modified electrode. The active substance of the test electrolyte is 4 mmol of 2,2,6,6-tetramethylpyridine-N-oxide (TEMPO), and the supporting electrolyte is 1.5 mol / L of NaCl solution. As Figure 2 shown, the polarization overpotential of the porous graphite felt electrode is significantly smaller than that of the unmodified graphite felt electrode, and the peak current of the porous graphite felt electrode is significantly larger than that of the unmodified graphite felt electrode.

[0043] As Figure 3 shown, the modified graphite felt electrode is assembled in an organic aqueous flow battery, where the positive active material is 0.4 mol / L TEMPO, the negative active material is 0.4 mol / L methyl viologen (MV), the supporting electrolyte is 2 mol / L NaCl solution, and an anion exchange membrane is selected as the battery separator. At a current density of 30 mA / cm 2 , the Coulombic efficiency is 98%, the voltage efficiency is 77%, and the energy efficiency is 75%.

[0044] Example 2

[0045] First, weigh 1.9862 g of (NH4)2SO4 with a balance and add it to a 250 mL beaker containing 100 mL of deionized water. Measure 100 mL of DMF with a measuring cylinder and place it in the above solution. Stir evenly at a constant temperature of 60 °C with a magnetic stirrer.

[0046] Use the stirred solution as the electrolyte solution for the electrochemical pretreatment experiment. The distance between the two electrodes is 4 cm, a voltage of 10 V is applied across the electrodes, the graphite felt is the positive electrode, the graphite felt is the negative electrode, and the reaction time is 20 min. After the electrochemical pretreatment is completed, ultrasonically rinse with deionized water and dry to obtain the positive graphite felt.

[0047] Weigh 0.01 g of graphene oxide with a balance and add it to 200 mL of DMF. Use a high-power ultrasonic disperser to ultrasonically pulverize at a power of 10% for 30 min. The pulverized solution is used as the electrolyte solution for the electrochemical etching experiment.

[0048] The pretreated graphite felt is the positive electrode, the pretreated graphite felt is the negative electrode, the distance between the two electrodes is 2 cm, a voltage of 3 V is applied across the electrodes, and the reaction time is 30 min. After the electrochemical etching is completed, ultrasonically rinse with deionized water and dry to obtain the negative graphite felt.

[0049] The modified graphite felt electrode is assembled in an organic aqueous flow battery, where the positive active material is 0.3 mol / L TEMPO, the negative active material is 0.3 mol / L methyl viologen (MV), the supporting electrolyte is 2 mol / L NaCl solution, and an anion exchange membrane is selected as the battery separator. At a current density of 40 mA / cm 2 , the Coulombic efficiency is 98%, the voltage efficiency is 67%, and the energy efficiency is 65%.

[0050] Example 3

[0051] First, weigh 2.6428 g of (NH4)2SO4 with a balance and add it to a 250 mL beaker containing 100 mL of deionized water. Measure 100 mL of DMF with a measuring cylinder and place it in the above solution. Stir evenly at a constant temperature of 80 °C with a magnetic stirrer.

[0052] The well - stirred solution was used as the electrolyte solution for the electrochemical pretreatment experiment. The distance between the two electrodes was 2 cm, a voltage of 5 V was applied across the electrodes, the graphite felt was used as the positive electrode, the graphite felt was used as the negative electrode, and the reaction time was 40 min. After the electrochemical pretreatment was completed, it was ultrasonically rinsed with deionized water and dried, and the positive graphite felt was taken.

[0053] Weighed 0.03 g of graphene oxide with a balance and added it to 200 mL of DMF. It was ultrasonically pulverized for 30 min with a high - power ultrasonic disperser at a power of 10%. The pulverized solution was used as the electrolyte solution for the electrochemical etching experiment.

[0054] The pretreated graphite felt was used as the positive electrode, the pretreated graphite felt was used as the negative electrode, the distance between the two electrodes was 1 cm, a voltage of 3 V was applied across the electrodes, and the reaction time was 40 min. After the electrochemical etching was completed, it was ultrasonically rinsed with deionized water and dried, and the negative graphite felt was taken.

[0055] The modified graphite felt electrode was assembled in an organic - aqueous redox flow battery. The positive active material was 0.4 mol / L TEMPO, the negative active material was 0.4 mol / L methyl viologen (MV), the supporting electrolyte was 1.5 mol / L NaCl solution, and an anion - exchange membrane was selected as the battery separator. At a current density of 20 mA / cm 2 the Coulombic efficiency was 98%, the voltage efficiency was 82%, and the energy efficiency was 78%.

[0056] Example 4

[0057] First, weighed 2.6428 g of (NH4)2SO4 with a balance and added it to a 250 - mL beaker containing 100 mL of deionized water. Measured 100 mL of DMF with a measuring cylinder and placed it in the above - mentioned solution. It was stirred evenly at a constant temperature of 60 °C with a magnetic stirrer.

[0058] The well - stirred solution was used as the electrolyte solution for the electrochemical pretreatment experiment. The distance between the two electrodes was 4 cm, a voltage of 10 V was applied across the electrodes, the graphite felt was used as the positive electrode, the graphite felt was used as the negative electrode, and the reaction time was 40 min. After the electrochemical pretreatment was completed, it was ultrasonically rinsed with deionized water and dried, and the positive graphite felt was taken.

[0059] Weighed 0.02 g of graphene oxide with a balance and added it to 200 mL of DMF. It was ultrasonically pulverized for 30 min with a high - power ultrasonic disperser at a power of 20%. The pulverized solution was used as the electrolyte solution for the electrochemical etching experiment.

[0060] The pretreated graphite felt was used as the positive electrode, the pretreated graphite felt was used as the negative electrode, the distance between the two electrodes was 1 cm, a voltage of 5 V was applied across the electrodes, and the reaction time was 30 min. After the electrochemical etching was completed, it was ultrasonically rinsed with deionized water and dried, and the negative graphite felt was taken.

[0061] The modified graphite felt electrode is assembled in an organic-aqueous redox flow battery, where the positive active material is 0.2 mol / L TEMPO, the negative active material is 0.2 mol / L methyl viologen (MV), the supporting electrolyte is 1.5 mol / L NaCl solution, and an anion exchange membrane is selected as the battery separator. At a current density of 30 mA / cm 2 , the Coulombic efficiency is 97%, the voltage efficiency is 72%, and the energy efficiency is 70%.

[0062] An electrode for an organic redox flow battery, which is prepared from the porous graphite felt electrode material obtained by the electrochemical etching method of any of the above embodiments.

[0063] As Figure 4 shown, the present invention provides an organic redox flow battery, comprising:

[0064] An electrolytic cell tank filled with an electrolyte, and the electrolyte includes a supporting electrolyte;

[0065] Two electrode plates are arranged oppositely, and one of the two electrode plates is the electrode for the organic redox flow battery prepared as above;

[0066] A battery separator is located in the electrolytic cell tank and divides the electrolytic cell tank into an anode region communicated with an electrolyte reservoir and a cathode region communicated with another electrolyte reservoir. One of the electrode plates is arranged in the anode region and the other electrode plate is arranged in the cathode region. The anode region has a positive electrolyte containing a positive organic active material, and the cathode region has a negative electrolyte containing a negative organic active material; the battery separator allows the supporting electrolyte to penetrate and prevents the positive organic active material and the negative organic active material from penetrating, and the positive organic active material and / or the negative organic active material is an organic active molecule;

[0067] A circulation pipeline that inputs or outputs the electrolyte in one of the electrolyte reservoirs to or from the anode region and inputs or outputs the electrolyte in the other electrolyte reservoir to or from the cathode region.

[0068] A circulation pump is arranged on the circulation pipeline to make the electrolyte circulate.

[0069] The above-mentioned organic active materials are preferably viologens and TEMPOs; the concentration of the organic active material is 2-4 mol / L.

[0070] The organic active molecule includes derivatives obtained by performing water-soluble modification of amino, hydroxyl or carbonyl functional groups on it.

[0071] The supporting electrolyte is preferably a single-component neutral NaCl aqueous solution, and the concentration of the supporting electrolyte is 0.1-3 mol / L.

[0072] The battery separator is preferably an anion exchange membrane, and the thickness of the battery separator is 1 μm to 5 mm.

[0073] Based on the above organic flow battery, the present invention also provides a flow battery energy storage system based on a salt cavern, as Figure 5 shown. The energy storage system includes the above organic flow battery, and further includes: two electrolyte storage reservoirs, which are arranged opposite to each other at intervals. The electrolyte storage reservoir is a salt cavern with a physical solution cavity formed after salt mining. The physical solution cavity stores an electrolyte. The electrolyte includes a positive electrode active material, a negative electrode active material, and a supporting electrolyte. The electrolyte is protected under an inert gas environment to prevent the oxidized positive electrode active material and negative electrode active material from being reduced. The organic flow battery is respectively connected to the two electrolyte storage reservoirs.

[0074] Inspired by the above ideal embodiments according to the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An electrode material of porous graphite felt for an organic aqueous flow battery by electrochemical etching, characterized in that: The porous graphite felt electrode material is prepared by the following method, which has the following steps: Step 1: Prepare a mixed solution of N,N-dimethylformamide and (NH4)2SO4 as the electrolyte solution, and stir it evenly at a constant temperature with a magnetic stirrer: Weigh 0.6607 g to 3.9642 g of (NH4)2SO4 with an analytical balance and add it to 100 mL of deionized water; Measure 100 to 200 mL of N,N-dimethylformamide and add it to the (NH4)2SO4 solution; The constant temperature stirring temperature of the magnetic stirrer is 60 to 80 °C; Step 2: Conduct an electrochemical pretreatment experiment with a graphite felt as the positive electrode and a graphite felt as the negative electrode. After completion, ultrasonically wash it with deionized water and dry it. Take the positive electrode graphite felt for the electrochemical etching experiment. In the electrochemical etching experiment, the distance between the positive and negative electrodes is 2 to 5 cm, the voltage applied across the positive and negative electrodes is 5 to 10 V, and the pretreatment time is 10 to 40 min; Step 3: Add graphene oxide to the measured N,N-dimethylformamide and ultrasonically pulverize it with a high-power ultrasonic disperser for use as the electrochemical etching electrolyte solution; The mass of the graphene oxide is 0.01 g to 0.03 g, and 200 mL of N,N-dimethylformamide is measured; Step 4: Use the pretreated graphite felt as the positive electrode and the pretreated graphite felt as the negative electrode, apply a voltage across the positive and negative electrodes, and conduct an electrochemical etching experiment. After the electrochemical etching is completed, ultrasonically wash it with deionized water and dry it. Take the negative electrode graphite felt; In the electrochemical etching experiment, the distance between the positive and negative electrodes is 1 to 4 cm, the voltage applied across the positive and negative electrodes is 3 to 10 V; The electrochemical etching treatment time is 30 to 90 min.

2. The electrochemical etching porous graphite felt electrode material for an organic aqueous flow battery as described in claim 1, wherein: In the step 3, the power of the high-power ultrasonic disperser is 10 to 20%, and the pulverization time is 10 to 30 min.

3. An organic aqueous flow battery, characterized in that: It includes: An electrolytic cell tank filled with an electrolyte solution in the electrolytic cell tank, and the electrolyte solution includes a supporting electrolyte; Two electrode plates are arranged opposite to each other. One of the two electrode plates is the porous graphite felt electrode material for an organic aqueous redox flow battery described in claim 1 or 2; A battery separator is located in the electrolytic cell tank and divides the electrolytic cell tank into an anode region communicated with one electrolyte reservoir and a cathode region communicated with another electrolyte reservoir. One of the electrode plates is arranged in the anode region and the other electrode plate is arranged in the cathode region. The anode region has a positive electrode electrolyte containing a positive electrode organic active substance, and the cathode region has a negative electrode electrolyte containing a negative electrode organic active substance; The battery separator allows the supporting electrolyte to penetrate and prevents the positive electrode organic active substance and the negative electrode organic active substance from penetrating. The positive electrode organic active substance and / or the negative electrode organic active substance is an organic active molecule; A circulation pipeline that inputs or outputs the electrolyte solution in one of the electrolyte reservoirs to or from the anode region and inputs or outputs the electrolyte solution in the other electrolyte reservoir to or from the cathode region; A circulation pump is arranged on the circulation pipeline to circulate the electrolyte solution.

4. The organic aqueous flow battery according to claim 3, wherein: The battery separator is an anion exchange membrane.

5. The organic aqueous flow battery according to claim 4, wherein: The thickness of the battery separator is 1 μm to 5 mm.

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