A type of hybrid redox electrolyte and aqueous organic flow battery

Abstract

This invention discloses a homogeneous mixed redox electrolyte and an aqueous organic flow battery, belonging to the field of organic flow battery technology. The homogeneous mixed redox electrolyte can be used as either the positive or negative electrode. The positive electrode electrolyte incorporates at least two cyclic nitrile radical-based active materials, and the negative electrode electrolyte incorporates at least two viologen-based active materials. By introducing derivative molecules of the same type but different substituents or bridging atoms into the positive and negative electrode electrolytes, and utilizing the same charged groups or atoms in the substituents, the intermolecular distance is increased through electrostatic repulsion or weak interactions such as hydrogen bonds to stabilize the molecular structure, regulate the molecular distribution in solution, reduce molecular aggregation, and improve battery capacity and cycle stability. The introduction of charged active materials can enhance the battery's rate performance, facilitating higher power density and providing new ideas for the design and application of high-performance aqueous organic flow batteries.

Description

Technical Field

[0001] This invention belongs to the field of large-scale energy storage technology, specifically relating to a hybrid redox electrolyte and an aqueous organic flow battery. Background Technology

[0002] Driven by the energy revolution, developing clean energy sources such as wind, tidal, and solar power to achieve a sustainable transformation of the energy system has become an urgent need. However, renewable energy is constrained by natural conditions, exhibiting significant intermittency and instability, which impacts grid operation. Therefore, developing new energy storage technologies to achieve grid integration and improve energy utilization efficiency is crucial. Flow batteries, with their energy and power decoupling characteristics, are highly compatible with the needs of large-scale energy storage technologies. Among them, neutral aqueous flow batteries, with their unique advantages such as high safety, flexible structural design, rapid kinetic response, and environmental friendliness, demonstrate broad prospects for large-scale energy storage applications.

[0003] Currently, neutral aqueous organic flow batteries commonly employ cyclic nitrile radical-based positive electrode electrolytes and viologen-based negative electrode electrolytes. Cyclic nitrile radical molecules possess advantages such as high redox potential, excellent redox reversibility, environmental friendliness, and ease of synthesis and optimization. Viologen molecules, on the other hand, feature multi-step electron transfer, low redox potential, and excellent solubility. Both are widely used in neutral aqueous organic flow batteries. However, both cyclic nitrile radical and viologen molecules exhibit intermolecular aggregation. Specifically, during redox processes, cyclic nitrile radical molecules generate inactive hydroxylamine, where hydrogen atoms interact with oxygen atoms in other molecules through hydrogen bonds, forming a dimer structure. This reduces the number of redox-active molecules in the electrolyte. In the single-electron reduced state, viologen molecules exhibit polymerization due to the attraction between the negatively charged intermolecular radicals and the positive charge on the quaternary ammonium salt ions, and the conjugation of the benzene rings between molecules. This further reduces the number of active reactive molecules, resulting in decreased battery capacity and reduced cycle stability. The current main approach involves grafting charged substituents onto the parent molecule through molecular modification. This utilizes the repulsive effect of like charges between the substituents to reduce molecular aggregation, thereby improving battery capacity and cycle stability. However, molecular modification methods often cannot simultaneously achieve all the advantages, and are typically time-consuming, costly, and complex. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hybrid redox electrolyte and aqueous organic flow battery to solve the problems of reduced battery capacity and poor cycle stability caused by the aggregation of cyclic nitric oxide radicals and viologen molecules in the prior art.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A similar mixed redox electrolyte includes a redox active substance and a supporting electrolyte, wherein the redox active substance is composed of at least two active substances, including an electrically neutral active substance and a charged active substance;

[0007] When the redox electrolyte of the same type is used as a positive electrode electrolyte, the active substances are all cyclic nitric oxide free radical active substances;

[0008] When the redox electrolyte of the same type is used as the negative electrode electrolyte, the active substances are all viologen-based active substances.

[0009] A further improvement of the present invention is that:

[0010] Preferably, when the mixed redox electrolyte is a positive electrode electrolyte, the electrically neutral active material has the following structural formula: (The formula is missing from the original text.)

[0011]

[0012] Wherein, R1 is a hydrogen atom, hydroxyl group, amino group, alkoxy group, carbonyl group, dimethylamino group or amide group.

[0013] Preferably, when the mixed redox electrolyte is the positive electrode electrolyte, the charged active material is a cyclic nitric oxide radical with the following structural formula:

[0014]

[0015] Wherein, R2 is a substituted or unsubstituted quaternary ammonium salt, sulfonate, carboxylate, or phosphate group, and the counterion is Cl. - Or Na + .

[0016] Preferably, when the mixed redox electrolyte is a negative electrode electrolyte, the electrically neutral active substance is an alkyl-substituted viologen.

[0017] Preferably, when the mixed redox electrolyte is the negative electrode electrolyte, the charged active material is viologen, with the following structural formula:

[0018]

[0019] Wherein, R3 is a substituted quaternary ammonium salt, phosphate, sulfonate, or carboxylate group, and X - It is a monovalent counterion, and n is an integer between 1 and 4. The value depends on the number of positive and negative ions in the R3 substituent and the sum of the two negative ions on the pyridine ring to satisfy charge balance.

[0020] Preferably, the concentration of the cyclic nitric oxide radical active material in the positive electrode electrolyte is 2 mM to 3 M.

[0021] Preferably, the concentration of the violane-like active substance in the negative electrode electrolyte is 2 mM to 3 M.

[0022] Preferably, the molar ratio of charged active material to electrically neutral active material in the active material is 1 to 10.

[0023] Preferably, the supporting electrolyte is an aqueous solution of inorganic salts.

[0024] An aqueous organic flow battery, comprising a positive electrolyte and a negative electrolyte; at least one of the positive electrolyte and the negative electrolyte is a similar mixed redox electrolyte as described above.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention discloses a homogeneous mixed redox electrolyte, which can be used as either a positive or negative electrode electrolyte. At least two cyclic nitric oxide radical-based active materials are added to the positive electrode electrolyte, and at least two viologen-based active materials are added to the negative electrode electrolyte. These active materials are of the same type but differ in their substituents or bridging atoms. The substituents contain groups or charged atoms of the same charge, increasing the intermolecular distance through electrostatic repulsion or stabilizing the molecular structure through weak interactions such as hydrogen bonds. This effectively regulates the distribution of molecules in the solution, reduces molecular aggregation, and significantly improves battery capacity and cycle stability. Furthermore, the introduction of charged active materials into the mixed electrolyte increases the ionic conductivity of both the positive and negative electrode electrolytes, thereby enhancing the battery's rate performance and facilitating the achievement of high power density. Compared to chemical modification methods, this invention is simple and easy to operate, suitable for the mass production of high-performance electrolytes, and provides a new approach for the practical application of flow batteries. Attached Figure Description

[0027] Figure 1 These are the cyclic voltammetry curves of the mixed positive electrode electrolyte in Example 1 of the present invention at different scan rates of 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s.

[0028] Figure 2 This is the curve showing the change of the peak redox current of the mixed positive electrolyte as a function of the square root of the scan rate in Example 1 of this invention;

[0029] Figure 3 The mixed positive electrolyte full cell in Example 2 of this invention operates at 30 mA / cm².2 Constant current charge-discharge cycle performance for 100 cycles.

[0030] Figure 4 These are the cyclic voltammetry curves of the mixed positive electrode electrolyte in Example 3 of the present invention at different scan rates of 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s.

[0031] Figure 5 This is the curve showing the change of the peak redox current of the mixed positive electrolyte as a function of the square root of the scan rate in Example 3 of the present invention;

[0032] Figure 6 The mixed positive electrode electrolyte in Example 4 of this invention is at 30 mA / cm 2 Circulation diagram of constant current for 100 cycles at current density;

[0033] Figure 7 These are the cyclic voltammetry curves of the mixed negative electrode electrolyte in Example 5 of the present invention at different scan rates of 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s and 625 mV / s.

[0034] Figure 8 This is the curve showing the change of the peak redox current of the mixed negative electrode electrolyte with the square root of the scan rate in Example 5 of the present invention;

[0035] Figure 9 The mixed negative electrode electrolyte full cell in Example 6 of this invention operates at 30 mA / cm². 2 Cyclic diagram after 100 cycles at current density;

[0036] Figure 10 The comparative electrolyte of this invention is used in a full cell at 30 mA / cm². 2 Constant current charge-discharge cycle performance for 100 cycles. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings:

[0038] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0039] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0040] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0041] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0042] The first aspect of this invention discloses the preparation of a homogeneous mixed redox electrolyte, wherein the mixed redox electrolyte is prepared as a positive electrode electrolyte or a negative electrode electrolyte; each type of mixed electrolyte includes an active material and a supporting electrolyte; the active material is of at least two kinds, one of which is an electrically neutral active material and the other is a charged active material. When the homogeneous mixed redox electrolyte is a positive electrode electrolyte, both active materials are cyclic nitroxide radicals; when the homogeneous mixed redox electrolyte is a negative electrode electrolyte, both active materials are viologens. This invention uses a simple physical method to mix homogeneous electrolytes, aiming to improve the aggregation degree of the system and enhance battery capacity and stability.

[0043] Specifically, the active material in the mixed positive electrode electrolyte is a cyclic nitrile oxide free radical type active material, with the following structural formula:

[0044]

[0045] I II

[0046] In Formula I, R1 is uncharged, and the cyclic nitroxide radicals of Formula I are electrically neutral active substances. In Formula II, R2 is charged, and the cyclic nitroxide radicals of Formula II are charged active substances. In electrically neutral active substances, R1 is a hydrogen atom, hydroxyl group, amino group, alkoxy group, carbonyl group, dimethylamine group, or amide group. In charged active substances, R2 is a substituted or unsubstituted quaternary ammonium salt, sulfonate, carboxylate, or phosphate group, and the counterion is Cl. - Or Na+ .

[0047] The active material in the negative electrode electrolyte is viologen, and its general formula for the active structural unit is shown in the figure:

[0048]

[0049] III

[0050] Among them, X - The reaction is a monovalent counterion; in Formula III, if R3 is uncharged, it is an electrically neutral active substance; if R3 is charged, it is a charged active substance. Specifically, the uncharged active substance R3 is an alkyl-substituted viologen, and the charged active substance R3 is a substituted quaternary ammonium salt, phosphate, sulfonate, or carboxylate group. X - For Cl - Or Na + n is an integer between 1 and 4, and its value depends on the number of positive and negative ions in the R3 substituent and the sum of the two negative ions on the pyridine ring to satisfy charge balance.

[0051] The above-described scheme involves mixing cyclic nitroxide radicals and their derivatives with atoms substituted with the same charge groups. This increases intermolecular distance through electrostatic repulsion or stabilizes the molecular structure through weak interactions such as hydrogen bonds, thereby regulating the molecular distribution in solution and inhibiting intermolecular aggregation. Furthermore, the addition of charged cyclic nitroxide radical active materials can improve the rate performance and power density of the battery.

[0052] As a preferred embodiment, the electrically neutral active substance in the mixed electrolyte cyclic nitric oxide radical class is any one of the following structural formulas:

[0053]

[0054] As a preferred embodiment, the charged active substance in the mixed electrolyte cyclic nitric oxide radical class is any one of the following structural formulas:

[0055]

[0056] As a preferred option, the molar ratio of charged active substances to electrically neutral active substances in cyclic nitric oxide radicals is 1 to 10.

[0057] As a preferred option, the active materials of the mixed electrolyte cyclic nitrogen and oxygen free radical positive electrode are of two or more types.

[0058] By employing the above-described scheme, viologen-based negative electrodes are mixed. Through the utilization of weak interactions such as Coulomb repulsion or hydrogen bonding between viologen molecules with grafted charged substituents, the molecular state in solution is controlled, reducing intermolecular aggregation behavior. This decreases the likelihood of forming low-activity aggregates in the single-electron reduced state, thereby improving the battery's cycle stability. Simultaneously, the mixing of charged viologen molecules increases the ion concentration of the system, enhancing the battery's rate performance.

[0059] As a preferred option, the electrically neutral active substance in the mixed electrolyte viologen is methyl viologen:

[0060]

[0061] As a preferred embodiment, the charged active substance in the mixed electrolyte viologen class is any one of the following structural formulas:

[0062]

[0063] As a preferred option, the molar ratio of charged active substances to electrically neutral active substances in the mixed electrolyte viologen is 1 to 10.

[0064] As a preferred option, the active materials of the mixed electrolyte viologen-based negative electrode electrolyte are of two or more types;

[0065] In an embodiment of the present invention, an aqueous solution of potassium chloride (KCl) is used as the supporting electrolyte, and the concentration of the supporting electrolyte is 1 mol / L.

[0066] This invention also discloses an aqueous organic flow battery, which comprises a positive electrode electrolyte, a positive electrode flow field plate, a positive electrode, an ion separator, a negative electrode, a negative electrode flow field plate, and a negative electrode electrolyte; wherein the active material in the positive electrode electrolyte is a mixture of cyclic nitric oxide free radicals and their derivatives; the active material in the negative electrode electrolyte is a mixture of viologens and their derivatives; and the supporting electrolyte is an aqueous potassium chloride solution.

[0067] Preferably, when using the above-mentioned mixed electrolyte full cell, the opposite electrolyte electrode can be any other type, such as an organic system, a zinc system, etc.

[0068] Preferably, the aqueous organic flow battery uses a copper plate as the current collector, a graphite plate as the flow field plate, and a carbon felt as the reaction electrode, with an ion exchange membrane separating the positive and negative electrodes.

[0069] The specific implementation method is as follows:

[0070] Example 1

[0071] 1.378 mg of positive electrode molecule-2 and 2.455 mg of positive electrode molecule-11 were weighed out, with a molar ratio of 1:1, and dissolved in 8 mL of 1 M KCl aqueous solution to prepare a 2 mM positive electrode electrolyte. Cyclic voltammetry was performed using a three-electrode system. The reference electrode was a silver / silver chloride electrode, the working electrode was a glassy carbon electrode, and the counter electrode was a platinum sheet electrode. The selected scan rates were 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s, and 625 mV / s. Figure 1 The cyclic voltammetry curves are shown. The redox peak current at different scan rates is fitted to the square root of the scan rate to obtain... Figure 2 As shown in the figure, the peak current exhibits a good linear relationship with the scan rate at different scan rates, indicating that the mixed cathode electrolyte molecules still possess their own excellent redox reversibility, and this process is diffusion-controlled. Furthermore, the addition of cathode molecule -11 results in two pairs of reversible redox peaks, indicating that the system undergoes a two-step, two-electron transfer, and the electrolyte potential increases after mixing, which is beneficial for constructing a high-voltage battery system.

[0072] Example 2

[0073] 51.675 mg of positive electrode molecule-2 and 92.058 mg of positive electrode molecule-11 were weighed out, with a molar ratio of 1:1, and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M positive electrode electrolyte. 450.3 mg of negative electrode molecule-3 was weighed out and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing. The above positive and negative electrode electrolytes were stored in separate positive and negative electrode reservoirs on opposite sides and circulated using a peristaltic pump. The positive and negative electrode materials and electrolytes circulate separately through pipes, converging on both sides of the separator. Redox reactions occur at the graphite felt electrodes on both sides of the separator. The positive and negative electrodes are connected to a power source or load. The circuit transfers electrons, and the separator transfers anions or cations, forming a closed circuit. The cycle stability of this battery is evaluated using a 30 mA / cm² pressure. 2 The current density was used for constant current charge and discharge testing, with a cutoff voltage range of 1.6 V-0.9 V. Figure 3 Test results show that the battery's initial coulombic efficiency is above 99%, the initial discharge capacity is 14.3 mAh, and after 100 cycles, the discharge capacity is 14 mAh, with a capacity decay rate of 0.021% / cycle. The average coulombic efficiency remains above 99.5%, indicating that the system has excellent cycle stability.

[0074] Example 3

[0075] 1.102 mg of positive electrode molecule-2 and 3.566 mg of positive electrode molecule-12 were weighed out, with a molar ratio of 2:3, and dissolved in 8 mL of 1 M KCl aqueous solution to prepare a 2 mM positive electrode electrolyte. Cyclic voltammetry was performed using a three-electrode system. The reference electrode was a silver / silver chloride electrode, the working electrode was a glassy carbon electrode, and the counter electrode was a platinum sheet electrode. The selected scan rates were 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s, and 625 mV / s. Figure 4 The cyclic voltammetry curves are shown. The redox peak current at different scan rates is fitted to the square root of the scan rate to obtain... Figure 5 As shown in the figure, the peak current exhibits a good linear relationship with the scan rate at different scan rates, indicating that the mixed electrolyte molecules still possess their own excellent redox reversibility, and this process is diffusion-controlled. Furthermore, the addition of cathode molecule -12 results in two pairs of reversible redox peaks, indicating that the system undergoes a two-step, two-electron transfer, and the system potential increases, which is beneficial for constructing a high-voltage battery system.

[0076] Example 4

[0077] 41.34 mg of positive electrode molecule-2 and 133.708 mg of positive electrode molecule-12 (molar ratio of 2:3) were weighed and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M positive electrode electrolyte. Similarly, 450.3 mg of negative electrode molecule-3 was weighed and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing. The positive and negative electrode electrolytes were stored separately in two separate positive and negative electrode reservoirs and circulated using a peristaltic pump. The positive and negative electrode materials and electrolytes circulate separately through pipes, converging on both sides of the separator. Redox reactions occur at the graphite felt electrodes on both sides of the separator. The positive and negative electrodes are connected to a power source or load. The circuit transfers electrons, and the separator transfers anions or cations, forming a closed circuit. The cycle stability of this battery is evaluated using a 30 mA / cm² pressure. 2 The current density was used for constant current charge and discharge testing, with a cutoff voltage range of 1.6 V-0.9 V. Figure 6Test results show that the initial coulombic efficiency is above 99%, the initial discharge capacity is 13.3 mAh, and after 100 cycles, the discharge capacity is 13.1 mAh, with a capacity decay rate of 0.015% / cycle, indicating that the system has excellent cycling stability.

[0078] Example 5

[0079] 2.057 mg of negative electrode molecule-1 and 4.003 mg of negative electrode molecule-3 were weighed out, with a molar ratio of 1:1, and dissolved in 8 mL of 1 M KCl aqueous solution to prepare a 2 mM negative electrode electrolyte. The solution was bubbled under nitrogen for 30 min to remove oxygen. Cyclic voltammetry was performed using a three-electrode system, with a silver / silver chloride electrode as the reference electrode, a glassy carbon electrode as the working electrode, and a platinum sheet electrode as the counter electrode. The selected scan rates were 25 mV / s, 64 mV / s, 100 mV / s, 225 mV / s, 400 mV / s, and 625 mV / s. Figure 7 The cyclic voltammetry curves are shown. The redox peak current at different scan rates is fitted to the square root of the scan rate to obtain... Figure 8 As can be seen from the figure, the peak current shows a good linear fit with the scan rate at different scan rates, indicating that the mixed electrolyte molecules still have their own excellent redox reversibility, and the process is diffusion-controlled.

[0080] Example 6

[0081] 77.148 mg of negative electrode molecule-1 and 150.111 mg of negative electrode molecule-3 were weighed out, with a molar ratio of 1:1, and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M negative electrode electrolyte. 224.82 mg of positive electrode molecule-10 was weighed out and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 0.1 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing. The above positive and negative electrode electrolytes were stored in separate positive and negative electrode reservoirs on opposite sides and circulated using a peristaltic pump. The positive and negative electrode materials and electrolytes circulate separately through pipes, converging on both sides of the separator. Redox reactions occur at the graphite felt electrodes on both sides of the separator. The positive and negative electrodes are connected to a power source or load. The circuit transfers electrons, and the separator transfers anions or cations, forming a closed circuit. The cycle stability of this battery is evaluated using a 30 mA / cm² pressure. 2 The current density was used for constant current charge and discharge testing, with a cutoff voltage range of 1.6 V-0.8 V. Figure 9Test results show that the battery has an initial coulombic efficiency of over 99%, an initial discharge capacity of 10.6 mAh, and a discharge capacity of 9.6 mAh after 100 cycles, with a capacity decay rate of 0.094% / cycle, indicating that the system has excellent cycle stability.

[0082] Comparative Example 1

[0083] 103.35 mg of positive electrode molecule-2 was weighed and dissolved in 6 mL of 1 M KCl aqueous solution, and stirred thoroughly for 30 min to prepare a 0.1 M positive electrode electrolyte. 154.296 mg of negative electrode molecule-1 was weighed and dissolved in 6 mL of 1 M KCl aqueous solution, and stirred thoroughly for 30 min to prepare a 0.1 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing. The above positive and negative electrode electrolytes were stored separately in positive and negative electrode reservoirs on opposite sides and circulated using a peristaltic pump. The positive and negative electrode electrolytes circulated through pipes and converged on both sides of the separator. Redox reactions occurred at the graphite felt electrodes on both sides of the separator. The positive and negative electrodes were connected to a power source or load. The circuit transferred electrons, and the separator transferred anions or cations, forming a circuit. The cycle stability of the battery was evaluated using a 30 mA / cm² test. 2 The current density was used for constant current charge and discharge testing, with a cutoff voltage range of 1.6 V-0.8 V. Figure 10 The test results show that the initial coulombic efficiency is above 98%, the initial discharge capacity is 12.4 mAh, and after 100 cycles, the discharge capacity is 9.3 mAh, with a capacity decay rate of 0.25% / cycle, indicating that the comparative ratio has poor cycle stability.

[0084] Example 7

[0085] 0.345 g of positive electrode molecule-2 and 3.069 g of positive electrode molecule-11 (molar ratio of 1:5) were weighed and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 2 M positive electrode electrolyte. 9.007 g of negative electrode molecule-3 was weighed and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 2 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing.

[0086] Example 8

[0087] 0.094 g of positive electrode molecule-2 and 2.026 g of positive electrode molecule-12 (molar ratio 1:10) were weighed and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 1 M positive electrode electrolyte. 4.503 g of negative electrode molecule-3 was weighed and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 1 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing.

[0088] Example 9

[0089] 0.387 g of positive electrode molecule-2 and 5.850 g of positive electrode molecule-12 (molar ratio 1:7) were weighed and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 3 M positive electrode electrolyte. 13.51 g of negative electrode molecule-3 was weighed and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 3 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing.

[0090] Example 10

[0091] 0.210 g of negative electrode molecule-1 and 4.094 g of negative electrode molecule-3 were weighed out, with a molar ratio of 1:10, and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 1.5 M negative electrode electrolyte. 3.372 g of positive electrode molecule-10 was weighed out and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 1.5 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing.

[0092] Example 11

[0093] 0.514 g of negative electrode molecule-1 and 5.324 g of negative electrode molecule-2, with a molar ratio of 1:5, were weighed and dissolved in 6 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 2 M negative electrode electrolyte. 4.496 g of positive electrode molecule-10 was weighed and dissolved in 9 mL of 1 M KCl aqueous solution. The solutions were stirred thoroughly for 30 min to prepare a 2 M negative electrode electrolyte. The prepared positive and negative electrode electrolytes were bubbled under nitrogen for 30 min to remove oxygen, and then transferred to a glove box for testing.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A homologous mixed redox electrolyte characterized in that, The redox active material is composed of at least two active materials, including an electrically neutral active material and a charged active material, and a supporting electrolyte; When the redox electrolyte is a positive electrolyte, the active materials are all cyclic nitroxyl radical materials; When the redox electrolyte is a negative electrolyte, the active materials are all viologen materials; When the redox electrolyte is a positive electrolyte, the electrically neutral active material is a cyclic nitroxyl radical, and the structure formula is: wherein R1 is a hydrogen atom, a hydroxyl group, an amino group, an alkoxy group, a carbonyl group, a dimethylamine group or an amide group; When the redox electrolyte is a positive electrolyte, the charged active material is a cyclic nitroxyl radical, and the structure formula is: wherein R2 is a substituted or unsubstituted quaternary ammonium, sulfonate, carboxylate or phosphate group, and the counterion is CI - or Na + ; When the redox electrolyte is a negative electrolyte, the electrically neutral active material is an alkyl-substituted viologen; When the redox electrolyte is a negative electrolyte, the charged active material is a viologen, and the structure formula is: wherein R3is a substituted quaternary ammonium, phosphonium, sulfonium or carboxylic acid salt group, X - is a monovalent counterion, and n is an integer from 1 to 4. The supporting electrolyte is an aqueous inorganic salt solution.

2. A homologous mixed redox electrolyte according to claim 1, characterized in that, The concentration of the cyclic nitroxyl radical material in the positive electrolyte is 2 mM to 3 M.

3. A homologous mixed redox electrolyte according to claim 1, characterized in that, The concentration of the viologen material in the negative electrolyte is 2 mM to 3 M.

4. The homologous mixed redox electrolyte according to claim 1, characterized in that, The molar ratio of the charged active material to the electrically neutral active material in the active material is 1 to 10.

5. An aqueous organic flow battery, characterized in that, The aqueous organic liquid flow battery comprises a positive electrolyte and a negative electrolyte; at least one of the positive electrolyte and the negative electrolyte is the same kind of mixed redox electrolyte according to claim 1.

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