Method and System for Reducing Crossover in Redox Flow Batteries

Abstract

This disclosure provides a redox flow battery with long operating time or long life for energy storage applications. A water-soluble perylenediimide molecule can be used as an energy storage material in the anode chamber, and a water-soluble ferrocene molecule can be used as an energy storage material in the cathode chamber. This redox flow battery has a substantially negligible crossover rate across the membrane.

Description

[Technical Field]

[0001] The present invention generally relates to methods and systems for reducing and preventing active species crossover in redox flow batteries. [Background technology]

[0002] A redox flow battery primarily consists of the following components: an electrolyte tank (cathodeli and anodelite), an electrochemical cell (for charging or discharging), a membrane for separating the electrolyte solution, and a pump that delivers the electrolyte to the electrochemical cell and returns it to the tank. One of the major challenges in flow batteries is the performance of the membrane that separates the cathodelite and anodelite. Separating the active components in the electrolyte from each other is important for maintaining the charged components (and their neutral components) in the appropriate tanks. When crossover of active species occurs, capacity loss in flow batteries can reach up to 50%. [Overview of the project] [Problems that the invention aims to solve]

[0003] This specification summarizes, and is described in detail below, redox flow batteries in which the crossover rate is substantially negligible. In many embodiments, a water-soluble redox-active organic molecule containing (but not limited to) a perylenediimide derivative is implemented as the anode for the redox flow battery. In several embodiments, one or both imide nitrogen atoms on the perylenediimide skeleton are covalently bonded to a substituent containing at least two cationic groups, or a substituent containing at least two anionic groups. Perylenediimide molecules having at least two cationic groups may be efficient in reducing crossover in redox flow batteries in which an anion exchange membrane is used to separate the anode and cathode compartments. In some embodiments, cationic groups containing (but not limited to) quaternary ammonium groups, imidazolium groups, and pyridinium groups are used to modify the perylenediimide. Perylenediimide molecules having at least two anionic groups may be efficient in reducing crossover in redox flow batteries in which anode and cathode compartments are separated using a cationic exchange membrane. In several embodiments, anionic groups, including but not limited to carboxylates, phosphonates, and sulfonic acid groups, are used to modify perylenediimide. The numerous cationic or anionic charges on the perylenediimide molecule in many embodiments can substantially minimize or prevent crossover of active species between the anode and cathode compartments of the battery.

[0004] In many embodiments, a water-soluble and redox-active organic molecule is implemented in the cathodic solution within the cathode chamber. Examples of redox-active molecules in the cathodic solution include (but are not limited to) ferrocene derivatives, TEMPO, ferrocyanides, iodine, or other cathodic materials. In some embodiments, the redox-active component of the cathodic solution includes a water-soluble ferrocene compound. In certain embodiments, the ferrocene skeleton is solubilized by the addition of an ionic scaffold containing at least two ionic groups. Any common ionic group, including (but not limited to) carboxylates, phosphonates, sulfonates, imidizolium, pyridinium, and thiazolium, may be used to solubilize the ferrocene skeleton. The ionic scaffold in some embodiments may contain (but are not limited to) ammonium ions, carboxylate ions, and sulfonate ions. In some embodiments, the scaffold of the ferrocene compound contains at least two cationic groups or at least two anionic groups. Ferrocene molecules having at least two cationic groups or at least two anionic groups may be effective in reducing and minimizing crossover in redox flow batteries. TEMPO modified with at least two ionic solubilizing groups, according to some embodiments, can reduce and / or minimize crossover in redox flow batteries under operating conditions. Compared to modified ferrocenes and modified TEMPO, ferrocyanides and iodine have much higher crossover rates because neither molecule has ionic solubilizing groups.

[0005] In many embodiments, the anode and cathode of the redox flow battery are aqueous electrolyte solutions with neutral and near-neutral pH values ​​of approximately pH 5 to approximately pH 9, or approximately pH 5.5 to approximately pH 8.5, or approximately pH 6 to approximately pH 8, or approximately pH 6.5 to approximately pH 7.5. Redox flow batteries according to several embodiments demonstrate that the crossover rate is substantially negligible under the battery's operating conditions. In some embodiments, the redox flow battery can be cycled for at least 90 days, and the crossover rate of the redox molecules is less than approximately 0.1%, or less than approximately 0.05%, or less than approximately 0.02%, or less than approximately 0.01%, or less than approximately 0.005%, or less than approximately 0.0005%. In many embodiments, the redox flow battery maintains a capacity retention rate of more than approximately 99% over a period of at least 14 days. In some embodiments, the redox flow battery maintains a capacity retention rate of more than approximately 99.9% over a period of at least 14 days.

[0006] Some embodiments include a redox flow battery comprising: a first half-cell containing a first aqueous solution comprising a first electrode and an anodelite containing a compound having a perylenediimide moiety, wherein the perylenediimide moiety comprises at least two ionic groups; a second half-cell containing a second aqueous solution comprising a second electrode and a cathodelite; and a separator interposed between the first half-cell and the second half-cell, wherein a concentration of less than 0.05% of the anodelite crosses over to the second half-cell via the separator, and a concentration of less than 0.05% of the cathodelite crosses over to the first half-cell via the separator.

[0007] In some embodiments, the separator is a size exclusion membrane or an ion exchange membrane.

[0008] In some embodiments, the separator is an anion exchange membrane or a cation exchange membrane.

[0009] In some embodiments, a concentration of less than 0.001% of the anode liquid crosses over to a second half-cell via a separator, and a concentration of less than 0.001% of the cathode liquid crosses over to a first half-cell via a separator.

[0010] In some embodiments, the compound is of formula (I) [ka] or having a salt thereof, T is -(LG) n -X is, T' represents H, (C1-C6) alkyl, or -(LG) n -X is, L is a -(C2-C5)-alkyl group, optionally substituted with OH, OCH3, or halogen. [ka] Each X is independently H, -(C1-C 10 ) alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. n=2 to 8, p = 3 to 20.

[0011] In some embodiments, T and T' are each independently -(LG) n -X is the case.

[0012] In some embodiments, L is selected from the group consisting of unsubstituted -(C2-C5)-alkyl, ethyl, and propyl.

[0013] In some embodiments, n is 2, 3, or 4.

[0014] In some embodiments, G is [ka] That is the case.

[0015] In some embodiments, X is H, methyl, or -CH2CH2OH.

[0016] In some embodiments, each X is independently H or -(C1-C6)-alkyl.

[0017] In some embodiments, at least one X is -CH3CH2OH.

[0018] In some embodiments, the compound of formula (I) is [ka] [ka] [ka] [ka] [Chemical formula] [Chemical formula] is as follows.

[0019] In some embodiments, the compound has the formula (II) [Chemical formula] where each Y is independently -O-, -S-, or -NH-; each q is independently from 1 to 8; each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6) alkenyl, -(C2-C6) alkynyl, and -(C1-C6) alkoxy, each of which is unsubstituted or independently substituted with 1, 2, or 3 R 1 groups; each R 1 is independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6) alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6) alkyl, -O(C=O)O(C1-C6) alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6) alkyl, O(C=O)N[(C1-C6) alkyl]2, -NH(C=O)(C1-C6) alkyl, N(C1-C6) alkyl(C=O)(C1-C6) alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6) alkyl, and N[(C1-C6) alkyl]2; each V is a counterion.

[0020] In some embodiments, the compound of formula (II) is [Chemical formula] That is the case.

[0021] In some embodiments, the compound is of formula (III) [ka] It has, Each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. Each s is independently between 2 and 4. Each R is independently H, -CH2OH, -CH2CH2OH, -CH2CH2OCH2CH2OH, or -CH2CH2OCH2CH2O(C1-6)alkyl. Each V - It is a counterion.

[0022] In some embodiments, the compound of formula (III) is [ka] [ka] That is the case.

[0023] In some embodiments, the compound is of formula (IV) [ka] It has, R is [ka] [ka] [ka] That is the case.

[0024] In some embodiments, the compound of formula (IV) is [ka] That is the case.

[0025] In some embodiments, the compound is of formula (V) [ka] or having a salt thereof, L is -(C1-C6)-alkyl, Each G is [ka] And, A is a positive ion, n=1 to 5

[0026] In some embodiments, L is substituted with OH, OCH3, and halogens.

[0027] In some embodiments, each A is lithium, sodium, potassium, or ammonium.

[0028] In some embodiments, each G is [ka] That is the case.

[0029] In some embodiments, each L is propyl.

[0030] In some embodiments, n is 2.

[0031] In some embodiments, LG n The group has at least one chiral center.

[0032] In some embodiments, formula (V) has at least one stereoisomer.

[0033] In some embodiments, the compound of formula (V) is [ka] That is the case.

[0034] In some embodiments, the compound of formula (V) is [ka] That is the case.

[0035] In some embodiments, the compound of formula (V) is [ka] That is the case.

[0036] In some embodiments, the compound of formula (V) is [ka] The group is selected from the group consisting of any combination of these.

[0037] In some embodiments, A is lithium, sodium, potassium, or ammonium.

[0038] In some embodiments, the compound of formula (V) is [ka] That is the case.

[0039] In some embodiments, the cathode liquid comprises a second compound having a ferrocene moiety.

[0040] In some embodiments, the second compound is [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] It has an expression selected from the group consisting of the following.

[0041] In some embodiments, the second compound is of formula (VI) [ka] It has, L is -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR 2 -(C1-C6)alkyl, or -(C1-C 10 )-alkyl-aryl, L' is -H, -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR2 -(C1-C6)alkyl, or -(C1-C 10 )-alkyl-aryl, G is [ka] Selected from the group consisting of, G is 2 or greater, A is Li, K, Na, or NH4. R 2 is, -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C 10 It is an alkyl-aryl, -aryl, or -(C=O)-(C1-C6)-alkyl.

[0042] In some embodiments, L is substituted with at least one group selected from the group consisting of G, -OH, -OCH3, and -halogens.

[0043] In some embodiments, L′ is substituted with at least one group selected from the group consisting of G, -OH, -OCH3, and -halogens.

[0044] In some embodiments, R 2 It is replaced by at least one G.

[0045] In some embodiments, LG n It has at least one chiral center.

[0046] In some embodiments, the compound has at least one stereoisomer.

[0047] In some embodiments, the compound of formula (VI) is [ka] That is the case.

[0048] In some embodiments, the compound of formula (VI) is [ka] That is the case.

[0049] In some embodiments, the compound of formula (VI) is [ka] That is the case.

[0050] In some embodiments, the compound of formula (VI) is [ka] The group is selected from the group consisting of any combination of these.

[0051] In some embodiments, the compound of formula (VI) is [ka] That is the case.

[0052] In some embodiments, the anode is perylenediimide-diammonium-Cl2 and the cathode is ferrocene-diammonium-Cl2.

[0053] In some embodiments, the anolyte is perylenediimide-diammonium-Cl2, and after cycling the redox flow battery for at least 90 days, a concentration of less than 0.0004% of the anolyte crosses over to a second half-cell via a separator.

[0054] In some embodiments, the cathode liquid is ferrocene-diammonium-Cl2, and after cycling the redox flow battery for at least 90 days, a cathode liquid concentration of less than 0.02% crosses over to the first half-cell via a separator.

[0055] Additional embodiments and configurations are described in part in the following description and will become apparent to those skilled in the art by a close examination of this specification or will be understood by carrying out the subject matter of the disclosed invention. A further understanding of the nature and advantages of this disclosure can be obtained by referring to the remainder of this specification and the drawings that constitute parts of this disclosure. [Brief explanation of the drawing]

[0056] [Figure 1] A calibration curve showing the detection limit of perylenediimide derivatives using visible absorption (UV-vis) according to one embodiment of the present invention is shown. [Figure 2] The UV-vis spectrum of a small sample taken from the analysis chamber of a crossover test according to one embodiment of the present invention is shown, indicating that the crossover of perylenediimide derivatives after 3 months is less than approximately 0.00004%. [Figure 3] A calibration curve showing the detection limit of ferrocene derivatives using UV-vis according to one embodiment of the present invention is shown. [Figure 4] The UV-vis spectrum of a small sample taken from the analysis chamber of a crossover test according to one embodiment of the present invention is shown, indicating that the crossover of ferrocene derivatives after 3 months is less than approximately 0.002%. [Figure 5] This shows a flow crossover test of Fc-MSG molecules according to one embodiment of the present invention. [Figure 6] This shows a flow crossover test of the Fc-BA molecule according to one embodiment of the present invention. [Figure 7] This shows the charge-discharge capacity of a cycling cell using Fc-Ac-SO3Na and MSG-PDI according to one embodiment of the present invention, and the capacity decrease observed with the crossover of Fc-Ac-SO3Na. [Figure 8]The HPLC spectra of the cathode and anode sides of an electrochemical cell using MSG-PDI and Fc-Ac-SO3Na according to one embodiment of the present invention are shown, indicating that the cathode crosses over to the anode chamber, but the anode does not cross over to the cathode chamber. [Figure 9] This embodiment demonstrates the stable Coulomb efficiency of a 10mAh flow cell and shows that the electrolyte molecules are resistant to crossover across the membrane. [Figure 10] This shows a redox flow battery according to one embodiment of the present invention. [Modes for carrying out the invention]

[0057] The following figures will provide a more comprehensive understanding of the contents of this specification. These figures are presented as illustrative embodiments of the present invention and should not be construed as a complete enumeration of the scope of the invention.

[0058] Here, with reference to the diagram, we describe a redox flow battery in which the crossover rate is virtually negligible. Redox flow batteries can use a wide variety of active materials to store energy. However, to create an attractive chemical system, several conditions must be met simultaneously. One challenge is to minimize the movement of active species across the membrane separating the cathode and anode, thereby minimizing the associated efficiency loss and capacity loss. Redox flow batteries using appropriate active materials that can mitigate crossover can improve battery performance (capacity) and durability (lifetime). The crossover rate and its effects depend on the properties of the active material, the migration speed through the separator, and the behavior after migration, respectively.

[0059] Crossover is an undesirable process in which electrolyte molecules permeate the membrane and diffuse into the opposite chamber. The migrated electrolyte, if charged, is consumed chemically or electrochemically. Once crossover occurs, the electrolyte can no longer be used to store charge, leading to an irreversible decrease in battery capacity. Furthermore, mixing with the opposite electrolyte makes it more susceptible to reactions and decomposition than when kept separately, potentially leading to degradation of the electrolyte solution. Redox flow batteries with high crossover rates may experience significant capacity loss and performance degradation, limiting their lifespan. Effectively eliminating crossover is necessary to ensure the potential for longer lifespan and higher capacity in flow batteries.

[0060] The membrane in a redox flow cell is crucial for the cell to function properly. The membrane, located between the anode and cathode in an electrochemical cell, must allow the diffusion of certain ions to maintain charge balance, while preventing the diffusion of all or part of the active charge storage electrolyte. Two types of membranes are used to meet this requirement: size exclusion membranes and ion exchange membranes. Size exclusion membranes are designed with distinct pore sizes, allowing small molecules (charge carriers or solvents) such as protons or small ionic salts to pass through, but retaining larger electrolyte molecules. Size exclusion membranes can be used with polymer electrolytes. Larger polymers may not be able to permeate and diffuse through the size exclusion membrane. Ion exchange membranes are designed to allow molecules with a certain charge polarity to pass through, while blocking molecules with the opposite polarity. In this way, the charged electrolyte is isolated on the appropriate side of the cell, while supporting ions with the opposite polarity can pass through to compensate for the charge changes caused by the electron flow.

[0061] In many embodiments, redox flow batteries are provided having anode liquid molecules and cathode liquid molecules in which membrane crossover is substantially negligible. Redox flow batteries according to some embodiments have long operating time or long life and a substantially negligible crossover rate in energy storage applications. In several embodiments, water-soluble perylenediimide molecules or perylenediimide-based molecules can be used as energy storage materials. In the anode chamber, molecules containing a neutral perylenediimide skeleton according to some embodiments are reduced during charging to store energy, and the reduced material is then oxidized during discharge to release energy. Similarly, in the cathode chamber, electrons are released from the charge storage material through an oxidation process during charging to store energy, and then reduced during discharge to release energy. In several embodiments, ferrocene molecules or ferrocene-based molecules are implemented as the cathode charge storage material.

[0062] In several embodiments, one or both imide nitrogen atoms on the perylenediimide skeleton can be covalently bonded to a substituent containing at least two cationic groups. In several embodiments, the perylenediimide molecule can be modified with at least two cationic groups, or at least three cationic groups, or at least four cationic groups, or at least five cationic groups. The numerous cationic groups on the perylenediimide skeleton may be the same or different. Examples of cationic groups include, but are not limited to, quaternary ammonium groups, imidazolium groups, and pyridinium groups. In many embodiments, perylenediimide molecules with fewer than two cationic groups are provided to have a higher crossover rate than perylenediimide molecules with at least two cationic groups. Perylenediimide molecules modified with at least two cationic groups, according to some embodiments, may be useful in redox flow batteries that separate anode and cathode compartments using an anion exchange membrane. In many embodiments, it is provided that any crossover between the anode and cathode compartments of the battery can be minimized and / or prevented by adding at least two positive ionic charges to the perylenediimide molecule. In some embodiments, the anolyte molecule can contain a number of positive charges to limit crossover between the cathode and anode chambers.

[0063] In many embodiments, one or both imide nitrogen atoms on the perylenediimide skeleton can be covalently bonded to a substituent containing at least two anionic groups. In some embodiments, the perylenediimide molecule can be modified with at least two anionic groups, or at least three anionic groups, or at least four anionic groups, or at least five anionic groups. The numerous anionic groups on the perylenediimide skeleton may be the same or different. Examples of anionic groups include, but are not limited to, carboxylate groups, phosphonate groups, and sulfonic acid groups. In many embodiments, perylenediimide molecules with fewer than two anionic groups offer a higher crossover rate than perylenediimide molecules with at least two anionic groups. Perylenediimide molecules modified with at least two anionic groups according to certain embodiments may be useful in redox flow batteries that separate anode and cathode compartments using a cation exchange membrane. In several embodiments, it is provided that the crossover between the anode and cathode compartments of the battery can be minimized and / or prevented by adding at least two negative ionic charges to the perylenediimide molecule. In some embodiments, the anolyte molecule can contain a number of negative charges to limit the crossover between the cathode and anode chambers.

[0064] In many embodiments, the anodic solution of a redox flow cell can contain water-soluble perylenediimide (PDI) molecules. The highly conjugated, electron-deficient framework of PDI is readily and reversibly reduced to accept two electrons. For most purposes, perylenediimides having functional groups on one or both of the imide nitrogen atoms are synthesized from perylenetetracarboxylic dianhydride (PD / 1) by condensation with a primary amine. In this way, organically soluble, water-soluble, polymeric, and liquid crystalline perylenediimides have been developed, and the properties of perylenediimides can be modified by the selection of functional groups bonded to one or both of the nitrogen atoms. In several embodiments, it is provided that these molecular modifications can alter specific properties of perylenediimide, while these modifications do not significantly affect the charge storage stability of perylenediimide. Unbound by theory, the electron and frontier molecular orbital densities of the perylenediimide framework are concentrated in the aromatic main chain, meaning that the redox properties of N-functionalized perylenediimides are identical in energy level, reversibility, and stability in solution, with or without modification. As a result, such molecular modifications do not affect charge storage stability.

[0065] In certain embodiments, the perylenediimide molecule used as the anode liquid contains a perylenediimide redox skeleton covalently bonded to a solubilizing group. In several embodiments, the perylenediimide skeleton is solubilized by the addition of an ionic scaffold. Any common ionic group can be used to solubilize the perylenediimide skeleton, including, but not limited to, ammonium ions, carboxylates, phosphonates, sulfonates, imidizolium, pyridinium, and thiazolium. In some embodiments, one or both nitrogen atoms of the perylenediimide skeleton are covalently bonded to a quaternated aminoalkyl group. In certain embodiments, one or both nitrogen atoms of the perylenediimide skeleton are covalently bonded to a carboxylate group.

[0066] Perylenediimide molecules in many embodiments exhibit high stability in both charged and uncharged states. In some embodiments, perylenediimide molecules show good stability in the two-electron reduced state even when present at high concentrations in aqueous media. In addition, perylenediimide molecules are suitable for both ion exchange membranes and size exclusion membranes because they exhibit minimal crossover from the anode chamber to the cathode chamber.

[0067] In many embodiments, the perylenediimide molecule is provided to be water-soluble. In certain embodiments, the anolyte solution may contain the perylenediimide compound dissolved in water without the use of additional solvents. The perylenediimide compound can be dissolved in water, tap water, or deionized water (but not limited to these). In some embodiments, the anolyte may contain a supporting electrolyte containing (but not limited to) NaCl, KCl, NH4Cl, Na2SO4, MgCl2, or a mixture thereof. In certain embodiments, the anolyte solution may contain a cosolvent to increase the solubility of the perylenediimide compound in aqueous solution. Examples of cosolvents include (but not limited to) methanol, propylene carbonate, and ethylene glycol.

[0068] Perylenediimide molecules according to several embodiments may be highly stable under a variety of pH conditions. In some embodiments, the anodic solution can be prepared in an acidic, neutral, or basic aqueous medium. In several embodiments, the anodic solution can be prepared at a neutral pH (pH about 7) or pH about 6 to about 8, and further at pH about 6.5 to about 7.5. In several embodiments, the anodic solution is prepared in a basic medium. In these embodiments, the pH of the anodic solution may vary in the range of about 7.5 to about 10. In several embodiments, the anodic solution is prepared in an acidic medium, and the pH of the anodic solution is in the range of about 4 to about 6.5, or about 5 to about 6.5. In some embodiments, the pH of the anodic solution may be neutral or near neutral (in the range of pH about 5.5 to about 8.5). In several embodiments, the anodic solution can be prepared using tap water.

[0069] In various embodiments, the perylenediimide compound has the structure of formula (I). [ka] or it may have a salt thereof. T=-(LG) n -X is, T'=H, C 1-6 Alkyl, or -(LG) n -X is, L=-(C2-C5)-alkyl, optionally substituted with OH, OCH3, or halogen, [ka] And, Each X is independently H, -(C1-C 10 ) alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. n=2 to 8, p = 3 to 20.

[0070] In the compound of formula (I), each LG group of variable T may be the same or different. In some embodiments, when n is 2, each L may be ethyl. In certain embodiments, the first L group may be ethyl and the second L group may be propyl. According to some embodiments, the G groups of variable T may be the same or different. In some embodiments, when n is 2, each G group of LG may be an ammonium group. In some embodiments, the first G group may be an ammonium group and the second G group may be a pyridinium group.

[0071] In some embodiments, the perylenediimide molecule of formula (I) may have a symmetric perylenediimide compound (i.e., T=T′). In certain embodiments, the perylenediimide compound is asymmetric (i.e., T and T′ are not equivalent).

[0072] In several embodiments, in the perylenediimide molecule of formula (I), each L in LG is either ethyl or propyl.

[0073] In some embodiments, the perylenediimide molecule is a compound in which n may be 2 in formula (I). In several embodiments, the perylenediimide molecule is a compound in which n may be 3 in formula (I). In a particular embodiment, the perylenediimide molecule is a compound in which n may be 4 in formula (I).

[0074] In many embodiments, in the perylenediimide molecule of formula (I), L may be an unsubstituted -(C2-C5)-alkyl group. In certain embodiments, L may be an unsubstituted ethyl group. In some embodiments, L may be an unsubstituted propyl group.

[0075] In some embodiments, in the perylenediimide molecule of formula (I), G is [ka] This is possible. In several embodiments, each X may be H. In various embodiments, each X may be methyl. In a particular embodiment, one X may be H and at least one other X may be methyl. In a particular embodiment, at least one X may be -CH2CH2OH.

[0076] In some embodiments, in the perylenediimide molecule of formula (I), each X may independently be H or -(C1-C6)-alkyl.

[0077] In several embodiments, in the perylenediimide molecule of formula (I), at least one X may be -(C1-C6)-alkyl-OH. In some embodiments, at least one X may be -CH3CH2OH.

[0078] In many embodiments, the compound of formula (I) has the following structure. [ka]

[0079] In certain embodiments, the compound of formula (I) has the following structure. [ka]

[0080] In some embodiments, the compound of formula (I) has the following structure. [ka]

[0081] In several embodiments, the compound of formula (I) has the following structure. [ka]

[0082] In many embodiments, the compound of formula (I) has the following structure. [ka]

[0083] In some embodiments, the compound of formula (I) has the following structure. [ka]

[0084] In several embodiments, the perylenediimide compound has the structure of formula (II). [ka] It has, Each Y is independently -O-, -S-, or -NH-. Each q is independently between 1 and 8. Each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. Each V is a counterion.

[0085] In some embodiments, the compound of formula (II) has the following structure. [ka]

[0086] In various embodiments, the perylenediimide compound has the structure of formula (III). [ka] It has, Each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. Each s is independently between 2 and 4. Each R is independently H, -CH2OH, -CH2CH2OH, -CH2CH2OCH2CH2OH, or -CH2CH2OCH2CH2O(C1-C6)alkyl. Each V is a counterion.

[0087] In several embodiments, the compound of formula (III) has the following structure. [ka]

[0088] In some embodiments, the compound of formula (III) has the following structure. [ka]

[0089] In certain embodiments, the perylenediimide compound has the structure of formula (IV). [ka]

[0090] In some embodiments, the compound of formula (IV) has the following structure. [ka]

[0091] In some embodiments, the perylenediimide compound has the structure of formula (V). [ka] or having a salt thereof, Each L is independently a -(C1-C6)-alkyl group, optionally substituted with OH, OCH3, and halogens. Each G is independent [ka] Selected from, A is a positive ion, n=1 to 5

[0092] In certain embodiments, in formula (V), A may be lithium, sodium, potassium, or ammonium.

[0093] In some embodiments, in formula (V), G is [ka] It is possible.

[0094] In several embodiments, L in formula (V) may be propyl.

[0095] In certain embodiments, n may be 2 in equation (V).

[0096] In a particular embodiment, LG n The group may have one or more chiral centers. In this case, the compound obtained from formula (V) may have several stereoisomers. In some embodiments, the compound may be a single stereoisomer. In other embodiments, the compound may be a mixture of two or more stereoisomers in any ratio. The mixture may contain all stereoisomers of the compound, or it may exclude one or more stereoisomers. If chirality is not shown for the stereocenter, the compound may consist of a mixture of any stereoisomers.

[0097] In many embodiments, the compound of formula (V) is [ka] It is possible.

[0098] In certain embodiments, the compound of formula (V) is [ka] It is possible.

[0099] In certain embodiments, the compound of formula (V) is [ka] It is possible.

[0100] In certain embodiments, the compound of formula (V) has the following stereoisomers [ka] It can be any mixture of the following.

[0101] In certain embodiments, the compound of formula (V) is [ka] It is possible.

[0102] Many embodiments of redox flow batteries may include a cathode solution in the cathode chamber. In some embodiments, the cathode solution contains water-soluble redox-active organic molecules. In certain embodiments, the redox-active component of the cathode may include (but are not limited to) TEMPO, ferrocyanides, iodine, or other cathode materials.

[0103] In some embodiments, the redox active component of the cathode solution is a water-soluble ferrocene compound. In certain embodiments, the ferrocene skeleton can be solubilized by the addition of an ionic scaffold. In several embodiments, the scaffold may contain an ammonium ion. In several embodiments, the scaffold may contain a carboxylate ion. In some embodiments, the scaffold may contain a sulfonate ion. The ferrocene skeleton can be solubilized using any common ionic group, including but not limited to carboxylates, phosphonates, sulfonates, imidizolium, pyridinium, and thiazolium.

[0104] In some embodiments, a ferrocene molecule can be modified with at least two cationic groups, or at least three cationic groups, or at least four cationic groups, or at least five cationic groups, or at least two anionic groups, or at least three anionic groups, or at least four anionic groups, or at least five anionic groups. The cationic and / or anionic groups may be the same or different. Examples of cationic groups include, but are not limited to, quaternary ammonium groups, imidazolium groups, pyridinium groups, imidazolium groups, and thiazolium groups. Examples of anionic groups include, but are not limited to, carboxylates, phosphonates, and sulfonic acid groups. In many embodiments, a ferrocene molecule with fewer than two cationic (anionic) groups is provided to have a higher crossover rate than a ferrocene molecule with at least two cationic (anionic) groups.

[0105] In many embodiments, the ferrocene molecule is provided to be water-soluble. In certain embodiments, the cathodic solution may contain a ferrocene compound dissolved in water without the use of an additional solvent. The ferrocene compound can be dissolved in water, tap water, or deionized water (but not limited to these). In some embodiments, the cathodic solution may contain a supporting electrolyte including (but not limited to) NaCl, KCl, NH4Cl, Na2SO4, MgCl2, or a mixture thereof. In certain embodiments, the cathodic solution may contain a cosolvent to increase the solubility of the ferrocene compound in aqueous solution. Examples of cosolvents include (but not limited to) methanol, propylene carbonate, and ethylene glycol.

[0106] In many embodiments, the catholyte solution can be prepared in an acidic, neutral, or basic medium. In several embodiments, the catholyte solution can be prepared at a neutral pH (pH of about 7), or at a pH from about 6 to about 8, and further from about 6.5 to about 7.5. Some embodiments prepare the catholyte solution in a basic medium, and the pH of the catholyte solution ranges from about 7.5 to about 10. In multiple embodiments, the catholyte solution can be prepared in an acidic medium, and the pH of the catholyte solution ranges from about 4 to about 6.5, or from about 5 to about 6.5. In some embodiments, the pH of the catholyte solution can be set to a neutral or near-neutral value (in the range of pH from about 5.5 to about 8.5). In several embodiments, the catholyte solution can be prepared using tap water.

[0107] In various embodiments, the ferrocene-based molecule has one of the following structures.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0108] In some embodiments, the ferrocene compound has the structure of formula (VI). [ka] It has, L is -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR 2 -(C1-C6)alkyl, -(C1-C 10 )-alkyl-aryl, each optionally substituted with one or more G, -OH, -OCH3, or -halogenates, L' is -H, -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR 2 -(C1-C6)alkyl, -(C1-C 10)-alkyl-aryl, each optionally substituted with one or more G, -OH, -OCH3, -halogen, each G is independently

Chemical formula

[0109] In certain embodiments, the L-G n group may have one or more chiral centers. In that case, the compound obtained from formula (VI) may have several stereoisomers. In some embodiments, the compound may be a single stereoisomer. In other embodiments, the compound may be a mixture of any ratio of two or more stereoisomers. The mixture may include all the stereoisomers of the compound, or may exclude one or more stereoisomers. If chirality is not indicated at the stereocenter, the compound may be composed of a mixture of any stereoisomers.

[0110] In certain embodiments, the compound of formula (VI) is

Chemical formula

[0111] In certain embodiments, the compound of formula (VI) is

Chemical formula

[0112] In certain embodiments, the compound of formula (VI) is [ka] It is possible.

[0113] In certain embodiments, the compound of formula (VI) has the following stereoisomers [ka] It can be any mixture of the following.

[0114] In certain embodiments, the compound of formula (VI) is [ka] It is possible.

[0115] In certain embodiments, the anolyte solution and / or the cathode solution may contain a supporting electrolyte. In some embodiments, the supporting electrolyte may not be essential to the anolyte solution and / or the cathode solution. Any supporting electrolyte, including but not limited to inorganic and organic salts, can be used. Typical inorganic salts include, but are not limited to, NaCl, KCl, LiCl, NaBr, KBr, LiBr, NaI, KI, LiI, MgCl2, CaCl2, MgBr2, CaBr2, MgI2, and CaI2, NH4Cl, NH4Br, and NH4I. Typical organic salts include, but are not limited to, alkylammonium chloride, alkylammonium bromide, alkylammonium iodide, sodium tosylate, and sodium besylate. In some embodiments, the solution may also contain, but are not limited to, a cosolvent including sulfolane or propylene carbonate.

[0116] In many embodiments, a redox flow battery comprises an anode solution and a cathode solution. The anode and cathode solutions can be pumped through tubes into a half-cell, where they undergo electrochemical reactions. The anode and cathode solutions can undergo repeated charge-discharge cycles within the half-cell. Materials used in the manufacture of battery components, including (but not limited to) electrodes, gaskets, flow plates, diodes, membrane frames, and membranes (also called separators), must be compatible with the anode and cathode solutions to ensure a long battery life. The membranes within the battery separate the anode and cathode sides. The membranes should prevent crossover of active species in each half-cell and preferably have high ionic conductivity, low area electrical resistance, and good chemical stability. The membranes within the battery may be ion-exchange membranes or size exclusion membranes. In many embodiments, the membranes of a redox flow battery can be made from non-fluorinated polymers. In some embodiments, the membrane can be made from hydrocarbon polymers including (but not limited to) polyethylene, polypropylene, polystyrene, and polyether ether ketones. These hydrocarbon membranes include (but not limited to) non-fluorinated charge-conducting groups including ammonia-modified polystyrene, ammonia-modified polyether ether ketones, sulfonated polyether ether ketones, and sulfonated polystyrene. In certain embodiments, Selemion is used as the anion exchange membrane in a redox flow battery. TM In a particular embodiment, in a redox flow battery, Selemion is used as the cation exchange membrane. TM In a particular embodiment, Fumasep is used as the anion exchange membrane in a redox flow cell. TM FAA-3-20 is used. In certain embodiments, Fumasep is used as the anion exchange membrane in a redox flow cell. TM FAA-3-50 is used. In certain embodiments, Fumasep is used as the anion exchange membrane in a redox flow cell. TM FAS-30 is used. In certain embodiments, Fumasep is used as the anion exchange membrane in a redox flow cell. TMFAM-PP is used. In certain embodiments, Fumasep is used as the anion exchange membrane in a redox flow battery. TM FAPQ-375-PP is used in a specific embodiment. In a redox flow cell, Fumasep is used as the cation exchange membrane. TM FKS-PK-75 is used. In certain embodiments, Fumasep is used as the cation exchange membrane in a redox flow cell. TM FKS-50 is used. In certain embodiments, Fumasep is used as the cation exchange membrane in a redox flow cell. TM Use the E620K.

[0117] Anodes containing perylenediimide according to several embodiments provide stability for long-life redox flow batteries. Cathodes containing ferrocene according to several embodiments also provide stability for long-life redox flow batteries. As used herein, the term “long-life” means a battery that has a stable capacity retention rate over repeated charge cycles or elapsed time. In many embodiments, a redox flow battery may have a lifespan of at least 5 years, or at least 10 years, or at least 20 years, or at least 50 years, or between 5 and 50 years, or between 10 and 50 years, or between 20 and 50 years.

[0118] Coulomb efficiency is a direct measure of molecular stability in organic flow batteries. Coulomb efficiency is the ratio of electrons discharged from the battery to the number of electrons charged during one cycle. For example, if a battery discharges 99 electrons from 100 electrons charged into the device in a given cycle, its Coulomb efficiency is 99%. This can be a direct measure of molecular stability in organic flow batteries. Electrons can be lost through various pathways other than molecular decomposition, such as solution leakage from the cell or crossover of active species across the membrane. However, molecular decomposition directly leads to a decrease in observed Coulomb efficiency. Not all decreases in Coulomb efficiency are due to molecular decomposition, but molecular decomposition does lead to a decrease in Coulomb efficiency. If the cause of the decrease in Coulomb efficiency is leakage, the molecules may be more stable than indicated by the Coulomb efficiency. On the other hand, molecules cannot be more unstable than indicated by the Coulomb efficiency. Any molecular decomposition results in a decrease in Coulomb efficiency. Examples of such decomposition include, but are not limited to, the disappearance of organic radicals on charged molecules through destructive chemical events such as dimerization, the formation of permanent bonds using two radicals, or attack by a solvent. If the Coulomb efficiency indicates a lifetime of 500 years, the molecular stability may be 750 years, but it will never be shorter than the 500 years indicated by the Coulomb efficiency.

[0119] In many embodiments, redox flow batteries comprising a stable, water-soluble perylenediimide anode and a stable, water-soluble ferrocene exhibit high Coulomb efficiency at a neutral pH (approximately pH 7) or near-neutral pH (approximately pH 6 to approximately pH 8, or approximately pH 5.5 to approximately pH 8.5). In several embodiments, the Coulomb efficiency of the redox flow battery may be at least 98% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In some embodiments, the Coulomb efficiency may be at least 98.5% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In certain embodiments, the Coulomb efficiency is at least 99% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In several embodiments, the Coulomb efficiency is at least 99.5% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In some embodiments, the Coulomb efficiency is at least 99.6% after at least about 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In certain embodiments, the Coulomb efficiency is at least 99.7% after at least about 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In many embodiments, the Coulomb efficiency is at least 99.9% after at least about 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In some embodiments, the Coulomb efficiency is about 100% after at least about 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In several embodiments, the Coulomb efficiency is about 98.5% to about 99.5% after at least about 200 charge / discharge cycles, or at least 380 charge / discharge cycles. In certain embodiments, the Coulomb efficiency is approximately 99% to approximately 99.5% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles.In several embodiments, the Coulomb efficiency is approximately 99.5% to approximately 99.9% after at least approximately 200 charge / discharge cycles, or at least 380 charge / discharge cycles.

[0120] Many embodiments of redox flow batteries exhibit high Coulomb efficiency, enabling longer lifespans for charge storage species within the battery. In several embodiments, the half-life of the species within the battery (i.e., the time required for the battery's charge storage capacity to be halved due to molecular degradation) can exceed approximately 10 years. In some embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 20 years. In certain embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 50 years. In some embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 70 years. In several embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 100 years. In various embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 200 years. In many embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 500 years. In some embodiments, the half-life of charge storage material for redox flow batteries can exceed approximately 1,000 years. In several embodiments, the half-life of the charge storage material for redox flow batteries can exceed about 2,000 years. In certain embodiments, the half-life of the charge storage material for redox flow batteries can exceed about 3,000 years. In some embodiments, the half-life of the storage material for redox flow batteries of this disclosure can exceed about 5,000 years. In multiple embodiments, the half-life of the charge storage material for redox flow batteries is between about 50 years and about 100 years. In some embodiments, the half-life of the charge storage material for redox flow batteries is between about 100 years and about 500 years. In various embodiments, the half-life of the charge storage material for redox flow batteries is between about 500 years and about 1,000 years. In some embodiments, the half-life of the charge storage material for redox flow batteries is between about 1,000 years and about 2,000 years. In several embodiments, the half-life of the charge storage material for redox flow batteries is between approximately 2,000 and 3,000 years. In certain embodiments, the half-life of the charge storage material for redox flow batteries is between approximately 2,000 and 5,000 years.

[0121] The performance of a redox flow battery can be evaluated by its capacity retention rate. If the loss of charge storage capacity over multiple charge / discharge cycles of a redox flow battery is minimal, it can be guaranteed to have a sufficient lifespan. In many embodiments, the loss of charge storage capacity over numerous charge / discharge cycles of a redox flow battery is minimal. In some embodiments, the loss of charge storage capacity after approximately 300 or 380 full charge / discharge cycles of a redox flow battery is less than approximately 2%. In several embodiments, the loss of charge storage capacity after approximately 300 or 380 full charge / discharge cycles of a redox flow battery is less than approximately 1%. In certain embodiments, the loss of charge storage capacity after approximately 300 or 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.5%. In various embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.25%. In several embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.1%. In some embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.05%. In several embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.03%. In some embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is less than approximately 0.01%. In certain embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is between approximately 0.05% and approximately 0.1%.In several embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is approximately 0.03% to approximately 0.1%. In some embodiments, the loss of charge storage capacity after approximately 300 full charge / discharge cycles or approximately 380 full charge / discharge cycles of a redox flow battery is approximately 0.01% to approximately 0.05%.

[0122] In many embodiments, the loss of charge storage capacity during operation of a redox flow battery is minimal. In some embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 2% per year. In several embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 1% per year. In certain embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.5% per year. In certain embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.25% per year. In some embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.1% per year. In several embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.05% per year. In certain embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.03% per year. In some embodiments, the loss of charge storage capacity of a redox flow battery is less than approximately 0.01% per year. In various embodiments, the loss of charge storage capacity of the redox flow battery is approximately 0.05% to approximately 0.1% per year. In several embodiments, the loss of charge storage capacity of the redox flow battery is approximately 0.03% to approximately 1% per year. In various embodiments, the loss of charge storage capacity of the redox flow battery is approximately 0.01% to approximately 0.05% per year. [Example Embodiments]

[0123] The following embodiments are provided to provide a complete disclosure and explanation of how those skilled in the art can manufacture and use the present invention, and are not intended to limit the scope of what the inventors consider to be their invention, nor to indicate that the experiments described below represent all or only experiments performed. While efforts have been made to ensure the accuracy of the numerical values ​​used (e.g., quantities, temperatures, etc.), some experimental errors and deviations should be taken into consideration. [Example 1. Crossover of Perylenediimide Molecules]

[0124] Water solubility can be increased by adding cationic or anionic groups to the perylenediimide skeleton molecule. In addition, the crossover between the anode and cathode compartments can be substantially reduced by adding additional cationic or anionic groups to the redox molecules of the skeleton. In many embodiments, a perylenediimide molecule is provided in which one or both imide nitrogen atoms on the perylenediimide skeleton are covalently bonded to substituents having at least two anionic groups or at least two cationic groups, thereby minimizing the crossover rate in a redox flow battery. In some embodiments, ammonium ions can be added to the perylenediimide skeleton molecule to reduce the crossover rate across anion exchange membranes. In several embodiments, a crossover test using the PDI-C3-NMe2-TEG molecule, represented by the following formula, is provided. [ka]

[0125] The crossover rate of PDI-C3-NMe2-TEG molecules can be tested using UV-Vis spectroscopy. Figure 1 shows the detection limits of PDI-C3-NMe2-TEG using UV-Vis according to one embodiment of the present invention. Figure 1 shows the calibration curve of concentration-dependent absorption of PDI by UV / Vis spectroscopy. PDI-C3-NMe2-TEG (dissolved in 1M NaCl solution) was tested by UV-Vis at concentrations of approximately 1 μM, 0.1 μM, 0.01 μM, and 0.001 μM. 1 μM PDI-C3-NMe2-TEG corresponds to a crossover of approximately 0.04%, shown in 101. 0.1 μM PDI-C3-NMe2-TEG corresponds to a crossover of approximately 0.004%, shown in 102. 0.01 μM PDI-C3-NMe2-TEG corresponds to a crossover of approximately 0.0004% and is shown as 103. 0.001 μM PDI-C3-NMe2-TEG corresponds to a crossover of approximately 0.00004% and is shown as 104. As shown in Figure 1, the PDI-C3-NMe2-TEG molecule showed observable absorbance at concentrations of approximately 1 μM 101, approximately 0.1 μM 102, and approximately 0.01 μM 103. No absorbance peak was shown in UV-Vis for 0.001 μM PDI-C3-NMe2-TEG 104. The UV-Vis test showed that the detection limit for PDI-C3-NMe2-TEG is approximately 0.01 μM.

[0126] For crossover rate testing, a solution of approximately 2.5 mM PDI-C3-NMe2-TEG can be prepared in a solution of approximately 1 M NaCl. Approximately 100 mL of this solution is used to prepare the membrane (Selemion). TM It can be added to one side of a redox flow cell chamber equipped with an AMVN. The cross-sectional area of ​​the film is approximately 5 cm². 2 The "blank" side on the opposite end of the battery is filled with approximately 100 mL of 1 M NaCl solution, and these solutions can be circulated at approximately 25 mL / min for approximately 90 days. After 90 days, UV-Vis data can be collected and analyzed from the blank side.

[0127] Figure 2 shows a time-dependent crossover test of the PDI-C3-NMe2-TEG molecule according to one embodiment of the present invention. Figure 2 shows the UV-vis measurement results 202 for the "blank" side of the redox flow battery and the measurement results 201 for the 1M NaCl solution after a 90-day cycle. As shown in Figure 2, no absorbance peak was detected for the PDI molecule by UV-Vis. Figure 2 shows a crossover rate of less than 0.0004% (4.4 × 10⁻⁶) over 90 days. -6 This indicates that it is % / day. [Example 2. Crossover of ferrocene molecules]

[0128] By adding cationic or anionic groups to the ferrocene skeleton molecule, water solubility can be increased, and crossover between the anode and cathode compartments can be reduced. In many embodiments, a ferrocene molecule having at least two anionic groups or at least two cationic groups is provided, which can minimize the crossover rate in redox flow batteries. In some embodiments, ammonium ions can be added to the ferrocene skeleton molecule to reduce the crossover rate across anion exchange membranes. Several embodiments provide crossover tests using the Fc-N2-5Me molecule represented by the following formula. [ka]

[0129] The crossover rate of Fc-N2-5Me molecules can be tested using UV-Vis testing. Figure 3 shows the detection limits of Fc-N2-5Me using UV-Vis according to one embodiment of the present invention. Fc-N2-5Me (dissolved in 1M NaCl solution) was tested by UV-Vis at concentrations of approximately 1mM 301, approximately 0.1mM 302, and approximately 0.01mM 303. 1M NaCl304 in water was used as the reference. 1mM Fc-N2-5Me 301 corresponds to a crossover of approximately 0.2%. 0.1mM Fc-N2-5Me 302 corresponds to a crossover of approximately 0.02%. 0.01mM Fc-N2-5Me 303 corresponds to a crossover of approximately 0.002%. As shown in Figure 3, Fc-N2-5Me molecules showed observable absorbance at concentrations of approximately 1 mM 301 and approximately 0.1 mM 302. No absorbance peak was observed in UV-Vis at 0.01 mM Fc-N2-5Me 303. UV-Vis testing indicated that the detection limit for Fc-N2-5Me is approximately 0.1 mM.

[0130] For crossover rate testing, a solution of approximately 50 mM Fc-N2-5Me can be prepared in a solution of approximately 1 M NaCl. Approximately 100 mL of this solution is used to prepare the membrane (Selemion). TM It can be added to one side of a redox flow cell chamber equipped with an AMVN. The cross-sectional area of ​​the film is approximately 5 cm². 2 The "blank" side on the opposite end of the battery is filled with approximately 100 mL of 1 M NaCl solution, and these solutions can be circulated at approximately 25 mL / min for approximately 90 days. After 90 days, UV-Vis data can be collected and analyzed from the blank side.

[0131] Figure 4 shows a flow crossover test of the Fc-N2-5Me molecule according to one embodiment of the present invention. Figure 4 shows the UV-vis measurement results 402 on the "blank" side of the redox flow battery and the measurement results 401 on the 1M NaCl solution after a 90-day cycle. As shown in Figure 4, no absorbance peak was detected by UV-Vis for the ferrocene molecule 402. Figure 4 indicates the absence of ferrocene, and the crossover rate after 90 days is less than 0.02% (2.2 × 10⁻⁶). -4 This indicates that it is % / day.

[0132] For crossover rate testing, approximately 0.68 M ferrocene monosodium glutamate (Fc-MSG) can be prepared in approximately 0.09 M NaCl solution. Approximately 8 mL of this solution is used to create a membrane (Selemion). TM It can be added to one side of an H-Cell battery chamber equipped with a CMVN. The cross-sectional area of ​​the film is approximately 3 cm². 2 The "blank" side opposite the H cell is filled with approximately 8 mL of a 1.45 M KCl solution, and these solutions can be stirred for 18 days. After 18 days, UV-Vis data can be collected and analyzed from the blank side.

[0133] Figure 5 shows a flow crossover test of Fc-MSG molecules according to one embodiment of the present invention. Figure 5 shows the UV-Vis measurement results on the 1.65M KCl side of the H cell battery. These are the UV-Vis measurement results for 503 after stirring for 0 days and 501 after stirring for 18 days. For reference, the result for 502 after stirring for 18 days on the Fc-MSG side is also shown. As shown in Figure 5, no absorbance peak was detected by UV-Vis for ferrocene molecule 501 on the 1.45M KCl aqueous solution side. Figure 5 shows that ferrocene is not present, and the crossover rate at 14 days is less than 0.02% (2.2 × 10⁻⁶). -4 This indicates that it is % / day.

[0134] For crossover rate testing, approximately 1.0 M ferrocene-butyric acid (or ferrocene-butanoic acid (Fc-BA)) can be prepared in approximately 0.1 M NaCl solution. Approximately 8 mL of this solution is used to prepare the membrane (Selemion). TM It can be added to one side of an H-Cell battery chamber equipped with a CMVN. The cross-sectional area of ​​the film is approximately 3 cm². 2 The "blank" side opposite the H cell is filled with approximately 8 mL of 1.1 M KCl solution, and these solutions can be stirred for 18 days. After 18 days, UV-Vis data can be collected and analyzed from the blank side.

[0135] Figure 6 shows a flow crossover test of Fc-BA molecules according to one embodiment of the present invention. Figure 6 shows the UV-Vis measurement results on the 1.1M KCl side of the H cell battery. These are the UV-Vis measurement results for 601 after stirring for 0 days and 602 after stirring for 18 days. For reference, 603 after stirring for 18 days on the Fc-BA side is shown. As shown in Figure 6, an absorbance peak due to UV-Vis was detected for Fc-BA molecules on the 1.1M KCl aqueous solution side of 603 after 18 days. Figure 6 shows the presence of ferrocene, and the crossover rate after 18 days exceeds 0.02% (2.2 × 10⁻⁶). -4 This shows the percentage per day. [Example 3. Crossover of Redox Flow Battery]

[0136] In many embodiments, ferrocene molecules with fewer than two anionic groups or fewer than two cationic groups are provided, resulting in a high crossover rate in redox flow batteries and causing degradation of battery capacity. In several embodiments, crossover tests with the Fc-Ac-SO3Na molecule represented by the following formula are provided. [ka]

[0137] The functional group on the ferrocene of the Fc-Ac-SO3Na molecule contains a single anionic group. Battery capacity can be tested by performing an H-cell test using the Fc-Ac-SO3Na molecule. (Carbon felt electrode and Selemion) TM A glass H-cell equipped with an AMVN membrane can be filled with approximately 1.25 mAh of Fc-Ac-SO3Na as the cathode liquid and approximately 1.25 mAh of monosodium glutamate-PDI (MSG-PDI) as the anode liquid, dissolved in approximately 1 M KCl aqueous solution at concentrations of approximately 0.006 M and 0.003 M, respectively. This cell can be charged and discharged 107 times over 30 days. [ka]

[0138] Figure 7 shows the charge and discharge capacity of an H cell according to one embodiment of the present invention. As shown in Figure 7, the charge and discharge capacity of the H cell during the cycles indicates the decrease in battery capacity caused by the Fc-Ac-SO3Na crossover. The total capacity loss from the first cycle to the 107th cycle was measured to be approximately 7.7%.

[0139] To analyze the cause of battery degradation, the composition of both the cathode and anode of the cell can be analyzed by HPLC. Figure 8 shows the HPLC spectra of the cathode and anode after an H-cell cycle test according to one embodiment. The HPLC data shows the separated spectra measured by UV / Vis absorption of the cathode solution (dashed line) and anode solution (solid line), and these separated spectra are superimposed. The peak at approximately 6.9 min corresponds to Fc-Ac-SO3Na. The peak at approximately 5.58 min corresponds to MSG-PDI. As shown in Figure 8, the cathode solution (Fc-Ac-SO3Na) does not contain anode (no crossover for MSG-PDI). The anode solution (MSG-PDI) contains approximately 5.4% of the total cathode (Fc-Ac-SO3Na) in the battery and shows a crossover for Fc-Ac-SO3Na, which explains the majority of the capacity loss. [Example 4. Coulomb Efficiency of Redox Flow Battery]

[0140] In many embodiments, redox flow batteries are provided with a Coulombic efficiency exceeding approximately 99.9%, where the crossover is substantially negligible. H-cells can be used for Coulombic efficiency testing. In H-cell testing, the anode liquid may contain PDI-tetraammonium-Cl4 in the anode liquid half-cell, and the cathode liquid may contain ferrocene-diammonium-Cl2 in the cathode liquid half-cell. The electrolyte can be dissolved in approximately 1 M sodium chloride for electrochemical stability testing. The number of moles of anode liquid and cathode liquid molecules present can be controlled to achieve a desired capacity of 1 mAh. During charge-discharge cycles, PDI-tetraammonium-Cl4 accepts and donates 2 electrons per molecule, while ferrocene-diammonium-Cl2 accepts and donates only 1 electron per molecule. Therefore, the molar concentration of PDI-tetraammonium-Cl4 in the H-cell is half the molar concentration of ferrocene-diammonium-Cl2. The H-cell contains Selemion TM Anion exchange membranes (AMVNs) are available. The H cells showed little crossover, and the average Coulomb efficiency after approximately 20 days of testing was nearly 100%.

[0141] Figure 9 shows cycle data obtained from a 10 mAh flow cell according to one embodiment of the present invention. The flow rate can be set to approximately 10 mL / min. The flow cell was run for approximately 20 days, for approximately 380 cycles. In this long-term cycle test shown in Figure 9, a Coulomb efficiency of over 99.9% was demonstrated. The average Coulomb efficiency was approximately 100%. [Example 5. Synthesis of N-butanoyl-4-ferrocenyliminodiacetic acid]

[0142] Several embodiments provide a synthesis scheme for N-butanoyl-4-ferrocenyliminodiacetic acid (the molecular structure shown below). Ferrocene butyric acid (10 g, 0.037 mol) was dissolved in DCM (50 mL), and a few drops of DMF were added. Oxalyl chloride (5.13 g, 3.47 mL, 0.40 mol) was added dropwise over 5 minutes, and the resulting mixture was stirred for 45 minutes. The solvent was removed using a rotary vacuum evaporator to obtain the product as a red oily substance. A solution of iminodiacetic acid (9.78 g, 0.074 mol) in 6 M NaOH (24 mL) was diluted with acetone (12 mL). The solution was diluted with water (30 mL) until the mixture was homogeneous. The iminodiacetic acid solution and the solvent-free acid chloride were simultaneously passed through a static mixer, and the resulting reaction mixture was stirred for 20 minutes. The reaction mixture was diluted to 150 mL. The pH was adjusted to 4.9 with 2M HCl, and the solution was extracted in two parts using DCM. The organic layer was discarded. The aqueous layer was adjusted to pH 2.8 with 6M HCl, and the solid was precipitated while vigorously stirring. The solid was recovered by filtration and washed twice more with water, 0.1M HCl, and water. The solid was dried to obtain the product as a grayish-yellow solid (7.74g, 0.02mol, 54%). 1H NMR: (d-DMSO, 500MHz) δ1.72-1.65(m, 2H), 2.29-2.24(m, 4H), 3.96(s, 1H), 4.03(t, J=1.75Hz, 2H), 4.075(t, J=1.8Hz, 1H), 4.11(s, 5H), 4.1(s, 5H), 4.14-4.12(bs, 2H). [ka] [Example 6. Synthesis of water-soluble perylenediimide redox active compound] The synthesis procedure for obtaining perylenediimide is described below. [ka]

[0143] PTCDA (2.35 g, 6 mmol) was suspended in dimethylacetamide (20 mL) and stirred. N,N-dimethyldipropylthriamine (1.96 g, 2.22 mL, 12.3 mmol) was added, and the solution was heated to 120°C. The solution was reacted at 120°C for 12 hours, and then cooled to room temperature. The reaction mixture was poured into siRNA (100 mL) and vigorously stirred. The precipitated solid was collected by filtration, washed with siRNA, and dried under high vacuum to obtain the product as a dark purple / red solid (2.5 g, 3.7 mmol, 62%). 1H NMR: (CDCl3, 300MHz) δ1.67(tt, J=7.1Hz, 7.1Hz, 4H), 1.97(tt, J=6.8Hz, 6.8Hz, 4H), 2.21(s, 12H), 2.32(t, J= 7.4Hz, 4H), 2.71(dt, J=18.2Hz, 7Hz, 8H), 4.23(t, J=6.8Hz, 4H), 8.13(d, J=7.2Hz, 4H), 8.35(d, J=7.8Hz, 4H). [ka]

[0144] Tetraamine PDI (1.35 g, 2 mmol) and potassium carbonate (0.829 g, 6 mmol) were suspended in methanol (20 mL). Methyl tosylate (4.47 g, 3.62 mL, 24 mmol) was added, and the reaction mixture was heated overnight at 55°C. The reaction mixture was cooled to room temperature, diluted with methanol (20 mL), and filtered to remove the white solid. The filtrate was concentrated to dryness using a rotary vacuum evaporator and dissolved in the minimum amount of methanol. Upon addition of acetone, a red solid precipitated from the solution. The solid was isolated by filtration and vacuum-dried at 55°C to obtain a dark red solid (2.05 g, 1.41 mmol, 71%). ¹H NMR: (D₂O, 300 MHz) δ 2.17(s, ¹²H, OTs) - ), 2.43-2.25(m, 8H), 3.14(s, 18H), 3.22(s, 12H), 3.38(m, 4H), 3.47(m, 4H) ), 3.62(m, 4H), 4.12(m, 4H), 7.29-7.10(bs, 4H), 7.17(d, J=8.2Hz, 8H, OTs -), 7.51(d, J=8.2Hz, 8H, OTs - ), 7.69 (bs, 4H). [ka]

[0145] Tetraammonium tosylate PDI (2.90 g, 2 mmol) was dissolved in concentrated HCl (20 mL). The resulting mixture was heated at 85°C for 24 hours. The reaction mixture was cooled to room temperature and diluted with isopropanol (60 mL) while vigorously stirring. The precipitated solid was collected by filtration, washed with isopropanol, and then vacuum-dried at 70°C to obtain the product as a red / black solid (1.6 g, 1.77 mmol, 88%). ¹H NMR: (D₂O, 300 MHz) δ 2.71-2.12 (bm, 8H), 3.90-2.99 (bm, 42H), 4.21 (bs, 4H), 8.39-6.96 (bm, 8H). [ka]

[0146] Glutamic acid and PTCDA were suspended in DMSO. Tribasic potassium phosphate was added under stirring, and the solution was heated to 120°C. The reaction mixture was stirred for 18 hours and then cooled to room temperature. 1M HCl was added, and the precipitated solid was filtered to obtain the product as a purple / black solid (100% relative to the recovered starting material). [ka]

[0147] Aspartic acid (2.93 g, 22 mmol) and PTCDA (3.92 g, 10 mmol) were suspended in ethylene glycol. Tribasic potassium phosphate (9.9 g, 46 mmol) was added, and the resulting solution was heated at 140°C for 12 hours. The reaction mixture was cooled to room temperature and poured into 1 M HCl (aqueous solution) (50 mL). The resulting precipitate was collected by filtration, washed with water, and then vacuum-dried at 55°C to obtain the product as a purple solid (1.914 g, 3.07 mmol, 31%). ¹H NMR: (D6-DMSO, 300 MHz) δ 2.85 (dd, J=16.6 Hz, 4.5 Hz, 2H), 3.42 (m, 2H), 6.08-6.01 (m, 2H), 8.43-7.67 (bm, 8H). [Example 7. Synthesis of water-soluble ferrocene-based redox-active compounds] [ka]

[0148] Ferrocene (50 g, 269 mmol, 1.1 equivalents) was added to a 3 L three-necked round-bottom flask equipped with a stirring bar, an addition funnel, and a gas outlet connected to a bubbler filled with saturated water-soluble NaHCO3. The apparatus was purged with dry nitrogen gas. Dichloromethane (600 mL) was added and stirred to dissolve the ferrocene. The mixture was cooled to 0°C in an ice bath. A stirring bar was placed in another round-bottom flask, and aluminum trichloride (35.9 g, 269 mmol, 1.1 equivalents) was added, and the flask was purged with dry nitrogen. Dichloromethane (600 mL) was added and stirred to suspend the aluminum trichloride. 4-Chlorobutyryl chloride (34.4 g, 245.5 mmol, 1.0 equivalent) was added dropwise to the aluminum trichloride suspension and stirred until the dissolution of aluminum trichloride stopped. The acid chloride mixture was decanted from undissolved aluminum trichloride into the addition funnel of the reaction apparatus. This solution was slowly added to the ferrocene solution in the reaction vessel at 0°C, taking care to ensure the mixture did not exceed 10°C. The mixture was then stirred for 3 hours while gradually warming the bath to room temperature. The vessel was cooled again to 0°C. In a separate flask, sodium borohydride (18.5 g, 489 mmol, 2.0 equivalents) was combined with digrime (70 mL) and dichloromethane (20 mL) under a nitrogen atmosphere. This mixture was transferred to the addition funnel of the reaction vessel and added dropwise to the reaction mixture. The reaction mixture was stirred at room temperature for 18 hours. 1M ammonium chloride aqueous solution (100 mL), water (100 mL), and saturated potassium sodium tartrate aqueous solution (400 mL) were added sequentially, and the reaction was stopped at 0°C. After gas generation ceased, the organic layer was collected, the aqueous layer was extracted with dichloromethane (3 washes, 100 mL each), the solvent was removed from the combined organic layers, and the resulting liquid was dissolved in 500 mL of hexane. The hexane layer was washed with water (8 washes, 200 mL each) to remove the digrime, and the mixture was dried by shaking over saturated sodium chloride aqueous solution. The organic layer was further dried with solid magnesium sulfate (100 g), filtered, and the solvent was removed to obtain the desired product as an orange oily substance (60 g, 88%). 1¹H NMR (300 MHz, chloroform-d) δ (ppm) 4.11 (overlap, 9H), 3.58 (t, J=7.0 Hz, 2H), 2.40 (t, J=7.8 Hz, 2H), 1.84 (dt, J=6.8, 7.8, 2H), 1.71 (dt, J=6.8, 7.0, 2H). [ka]

[0149] 4-chlorobutylferrocene (75 g, 276.6 mmol, 1.0 equivalent), N,N,N′,N′-tetramethyl-1,3-propanediamine (105 g, 814 mmol, 3 equivalents), and acetonitrile (500 mL) were mixed in a round-bottom flask and heated at 60°C for 12 hours. The mixture was cooled and washed with hexane (5 times, 150 mL each), and the acetonitrile layer was set aside. After removing the combined hexane layer, an orange liquid was obtained. To this liquid, N,N,N′,N′-tetramethyl-1,3-propanediamine (50 g, 388 mmol, 1.43 equivalents) and acetonitrile (250 mL) were added in a round-bottom flask, and the mixture was heated at 60°C for 12 hours. After cooling, the acetonitrile solution was washed with hexane (5 times, 150 mL each), and the acetonitrile layer was combined with the acetonitrile layer set aside in the previous step. The solvent was removed from the combined layers to obtain an orange oily substance. This oily substance was triturated with diethyl ether (200 mL) while sonicating. The ether was decanted, and the residual solvent was further removed under vacuum to obtain the product as a very viscous orange oily substance (97 g, 88%). ¹H NMR (300 MHz, chloroform-d) δ (ppm) 4.08 (overlap, 9H), 3.53 (overlap, 4H), 3.40 (s, 6H), 2.44 (t, J=7.9, 2H), 2.36 (t, J=6.0, 2H), 2.19 (s, 6H), 1.83 (m, 2H), 1.70 (m, 2H), 1.58 (m, 2H). [ka]

[0150] N-[3-(dimethylamino)propyl]-N,N-dimethylferrocenylbutaniminium chloride (97 g, 238 mmol, 1.0 equivalent) was dissolved in methanol (1000 mL). Iodomethane (101 g, 715.3 mmol, 3.0 equivalents) was slowly added using a syringe, and the mixture was stirred at room temperature for 12 hours. The solvent and unreacted iodomethane were removed under reduced pressure, and the residue was dissolved in water (200 mL). After stirring for 1 hour with Amberlite IRA-400 ion exchange resin beads (200 cm³), the resin was filtered off, and this solution was passed through an Amberlite IRA-400 ion exchange resin bead (500 cm³) column, with water used as the eluent. Water was removed from the resulting solution to obtain the product as a very viscous orange oily substance. This product crystallized when left standing (94.4g, 87%). ¹H NMR (300MHz, heavy water) δ (ppm) 4.20 (overlap 9H), 3.34 (overlap, 6H), 3.16 (s, 9H), 3.09 (s, 6H), 2.42 (t, J=7.0, 2H), 2.27 (m, 2H), 1.76 (m, 2H), 1.55 (m, 2H). [ka]

[0151] Ferrocene (10.0 g, 53.4 mmol, 1.00 equivalent) was added to a 1 L three-necked round-bottom flask equipped with a stirring bar, an addition funnel, a reflux condenser, and a gas outlet connected to a bubbler filled with saturated aqueous solution NaHCO3. The apparatus was purged with dry nitrogen gas. Dichloromethane (100 mL) was added and stirred to dissolve the ferrocene. The mixture was cooled to 0°C in an ice bath. A stirring bar was placed in another round-bottom flask, and aluminum trichloride (18.0 g, 134 mmol, 2.50 equivalent) was added, and the flask was purged with dry nitrogen. Dichloromethane (100 mL) was added and stirred to suspend the aluminum trichloride. 3-Chloropropionyl chloride (17.0 g, 134 mmol, 2.50 equivalent) was added dropwise to the aluminum trichloride suspension and stirred until the dissolution of aluminum trichloride stopped. The acid chloride mixture was decanted from undissolved aluminum trichloride into the reaction apparatus's addition funnel. This solution was slowly added to the ferrocene solution at 0°C, taking care to ensure the mixture did not exceed 10°C. The mixture was then refluxed for 16 hours. The vessel was cooled again to 0°C. In a separate flask, sodium borohydride (8.00 g, 214 mmol, 4.00 equivalents) was combined with digrimé (40 mL) and dichloromethane (20 mL) under a nitrogen atmosphere. This mixture was transferred to the addition funnel of the reaction vessel and added dropwise to the reaction mixture. The reaction mixture was stirred at room temperature for 18 hours. 100 mL of 1 M ammonium chloride aqueous solution, 100 mL of water, and 100 mL of saturated potassium sodium tartrate aqueous solution were added sequentially, and the reaction was stopped at 0°C. After gas generation ceased, the organic layer was collected, the aqueous layer was extracted with dichloromethane (3 washes, 50 mL each), the solvent was removed from the combined organic layers, and the resulting liquid was dissolved in 200 mL of hexane. The hexane layer was washed with water (8 washes, 200 mL each) to remove the digrime, and the mixture was dried by shaking over saturated sodium chloride aqueous solution. The organic layer was further dried with solid magnesium sulfate (50 g), filtered, and the solvent was removed to obtain the desired product X as an orange oily substance (13 g, 72%). 1H NMR (300 MHz, chloroform-d) δ (ppm) 4.10 (overlap, 8H), 3.58 (t, J=6.2 Hz, 4H), 2.50 (t, J=7.1 Hz, 4H), 1.98 (tt, J=6.2 Hz, 7.1 Hz, 4H). [ka]

[0152] 1,1′-Bis(3-chloropropyl)ferrocene (1.5 g, 4.4 mmol, 1.0 equivalent), potassium sulfite (8.4 g, 53 mmol, 12 equivalents), and water (100 mL) were added to a 250 mL round-bottom flask equipped with a condenser. The mixture was heated under reflux for 4 days. During this time, the immiscible ferrocene starting material gradually disappeared while being converted to a water-soluble product. The mixture was cooled and extracted with ethyl acetate (washed 3 times, 200 mL) to remove the starting material. Water was removed from the aqueous layer and methanol (100 mL) was added. This mixture was filtered, and methanol was removed by distillation. The resulting yellow solid was washed with a large amount of isopropanol to remove acetate. After drying, the product was obtained as a yellow powder (1.2 g, 54%). 1H NMR (300MHz, heavy water) δ (ppm) 4.06 (overlap, 8H), 2.84 (t, J=7.8Hz, 4H), 2.40 (t, J=7.6Hz, 4H), 1.98 (tt, J=7.8Hz, 7.6Hz, 4H). [ka]

[0153] Ferrocenebutanecarboxylic acid (1.00 g, 3.67 mmol) and N-hydroxysuccinimide (0.423 g, 3.67 mmol) were dissolved in DCM (18.5 mL), and the resulting mixture was stirred at room temperature. EDC (0.733 g, 4.04 mmol) was added, and the mixture was stirred overnight at room temperature. Triethylamine (2.02 g, 2.78 mL, 20 mmol) was added to a solution of glutamic acid (1.08 g, 7.3 mmol) dissolved in isopropanol (10 mL). After dissolving the glutamic acid, a crude solution of ferrocene N-hydroxysuccinimide activated ester was added to the glutamic acid mixture. The resulting mixture was stirred at room temperature for 12 hours, and then heated at 90°C for 12 hours. The reaction of the reaction mixture was stopped by adding 1 M NaOH, and washed with ethyl acetate. The aqueous layer was acidified with 1 M HCl and extracted with ethyl acetate. The ethyl acetate layer was washed with 0.01 M NaOH, and the aqueous washing solution was discarded. The organic layer was then extracted in two parts with 0.1 M NaOH. The aqueous extracts were combined, acidified with 1 M HCl, and extracted with siRNA. The organic extract was washed with water and saline solution, dried over magnesium sulfate, filtered, and concentrated to obtain the product as a yellow solid (0.200 g, 0.5 mmol, 14%). 1H NMR: (d-DMSO, 300MHz) δ1.83-1.63(m, 4H), 2.03-1.90(m, 1H), 2.14(t, J=7.2Hz, 2H), 2.32-2.23(m, 4H), 4 .05-4.01(m, 1H), 4.08(d, J=1.3Hz, 2H), 4.1(s, 5H), 4.21(dt, J=8.5Hz, 5.0Hz, 1H), 8.08(d, J=7.5Hz, 1H). [ka]

[0154] Synthesis of N-(4-ferrocenylbutanoyl)-L-glutamic acid. 4-ferrocenylbutanoic acid (68.0 g, 250 mmol, 1.0 equivalent), DCM (125 mL), and a stirring bar were placed in a 1 L round-bottom flask. Under positive pressure of N2 (g), oxalyl chloride (23.6 mL, 275 mmol, 23.6 mL, 1.20 equivalents) was slowly added dropwise while vigorously stirring, taking care to avoid gas generation. The dark brown solution was stirred at 25°C until gas generation slowed down (approximately 5 minutes). The reaction mixture was then heated further to 40°C and reacted for 1 hour. The solvent was removed using a rotary vacuum evaporator.

[0155] A solution of L-sodium glutamate monohydrate (143 g, 763 mmol, 3.05 equivalents), sodium hydroxide (30.0 g, 750 mol, 3.0 equivalents), and water (68 mL) was prepared at 100°C. Once all solids were dissolved, the pre-prepared ferrocenoate chloride was quickly added to the glutamate solution while stirring. The formation of a brown precipitate was observed during the addition of the acid chloride. Approximately 50 mL of additional water was added to facilitate stirring of the reaction mixture. The reaction mixture was reacted at 100°C for approximately 5 minutes. The reaction mixture was cooled to room temperature, and water was added to completely dissolve all solids. NaCl (solid) was added to completely saturate the aqueous solution. The resulting aqueous solution was titrated with HCl (6 M) to pH 5.8. Impurities were extracted with MeCN (4 × 200 mL). The resulting aqueous layer was further titrated with HCl (6 M) to pH 3. The product was extracted from the aqueous layer using MeCN, and this process was repeated until the resulting aqueous layer turned blue (3 × approximately 200 mL). Approximately 200 mL of silica and approximately 200 mL of anhydrous sodium sulfate were added to the acetonitrile solution. The acetonitrile suspension was stirred at room temperature for 30 minutes. The suspension was filtered through a frit glass filter, and the acetonitrile solution was recovered. The dark red solution was concentrated using a rotary vacuum evaporator. The resulting dark red oily substance was further concentrated under vacuum to obtain a dark yellowish-brown solid (53.8 g, 113 mmol, yield 45%, purity 84%). [ka]

[0156] Synthesis of N-butanoyl-4-ferrocenyliminodiacetic acid. Ferrocene butyric acid (10 g, 0.037 mol) was dissolved in DCM (50 mL), and a few drops of DMF were added. Oxalil chloride (5.13 g, 3.47 mL, 0.40 mol) was added dropwise over 5 minutes, and the resulting mixture was stirred for 45 minutes. The solvent was removed using a rotary vacuum evaporator to obtain the product as a red oily substance. A solution of iminodiacetic acid (9.78 g, 0.074 mol) in 6 M NaOH (24 mL) was diluted with acetone (12 mL). The solution was diluted with water (30 mL) until the mixture was homogeneous. The iminodiacetic acid solution and the solvent-free acid chloride were simultaneously passed through a static mixer, and the resulting reaction mixture was stirred for 20 minutes. The reaction mixture was diluted to 150 mL. The pH was adjusted to 4.9 with 2 M HCl, and the solution was extracted in two parts using DCM. The organic layer was discarded. The aqueous layer was adjusted to pH 2.8 with 6 M HCl, and the solid was precipitated while vigorously stirring. The solid was recovered by filtration and washed twice more with water, 0.1 M HCl, and water. The solid was dried to obtain the product as a grayish-yellow solid (7.74 g, 0.02 mol, 54%).

[0157] 1H NMR: (d-DMSO, 500MHz) δ1.72-1.65(m, 2H), 2.29-2.24(m, 4H), 3.96(s, 1H), 4.03(t, J=1.75Hz, 2H), 4.075(t, J=1.8Hz, 1H), 4.11(s, 5H), 4.1(s, 5H), 4.14-4.12(bs, 2H). [Example 8. H-cell experiment demonstrating the stability of anionic water-soluble perylenediimide and ferrocene electrolyte solution]

[0158] These experiments demonstrate that the disclosed anionic electrolyte solution is compatible in both charged and uncharged states. This static cell experiment setup allows for accurate measurement of Coulomb efficiency for analyzing the electrochemical and physical compatibility between the charged electrolyte solution and the cell manufacturing material. High Coulomb efficiency indicates that electrons introduced into the organic charge storage electrolyte during charging are returned during discharge; that is, the electrolyte does not react electrochemically or physically with anything, including the cell manufacturing material, in the charged state, and thus no charge is lost.

[0159] An exemplary 1 mAh H cell was prepared using glutamate PDI as the anodic solution half-cell and bis-propylsulfonate ferrocene as the cathode solution half-cell. The structures of these molecules are shown below. Figure 9 shows the cycles of glutamate-PDI and bis-propylsulfonate ferrocene. The cell was made of glass and the membrane was Selemion. TM CMV was used. Each half-cell was mixed with a PTFE stirrer, and the electrodes were carbon felt. Coulomb efficiency was measured over a series of cycles. From 10 to 40 cycles, the average Coulomb efficiency exceeded 99.9%, indicating that both the anode and cathode electrolyte solutions were stable. That is, electrochemical or physical degradation was minimal in the charged state. The capacity also remained stable. [ka] [ka]

[0160] An exemplary 1 mAh H cell was prepared using glutamate PDI as the anodic acid half-cell and glutamate amide ferrocene as the cathode acid half-cell. The structures of these molecules are shown below. Figure 10 shows the cycles of glutamate-PDI and bis-propylsulfonate ferrocene. The cell was made of glass, and the membrane used was SelemionCMV. Each half-cell was mixed with a PTFE stirrer, and the electrodes were carbon felt. The Coulomb efficiency was measured over a series of cycles. From 10 to 40 cycles, the average Coulomb efficiency exceeded 99.9%, indicating that both the anodic acid and cathode acid electrolyte solutions were stable. That is, electrochemical or physical degradation was minimal in the charged state. The capacity also remained stable. [ka] [ka] [Example 9. Redox flow battery]

[0161] Figure 10 shows a redox flow battery according to one embodiment in which the crossover rate is substantially negligible. A redox flow battery or a single cell 110 of a redox flow battery may include two half-cells. One of the two half-cells may be a cathode half-cell and the other an anode half-cell. The cathode liquid (or cathode electrolyte) 111 may be pumped to the cathode half-cell, and the anode liquid (or anode electrolyte) 114 may be pumped to the anode half-cell. The anode liquid solution and the cathode liquid solution may undergo repeated charge-discharge cycles within the half-cell. The cathode half-cell and the anode half-cell may be connected by a membrane 113 for ion transport. The half-cell of the battery includes, but is not limited to, electrodes, gaskets, flow plates, diode plates, and membranes. Materials used in the manufacture of battery components, including but not limited to electrodes, gaskets, flow plates, diodes, membrane frames, and membranes (also called separators), must be compatible with the anodic and cathode solutions to ensure a long battery life. In many embodiments, a redox flow battery may include at least one single cell, or at least two single cells, or at least five single cells, or at least ten single cells, or at least fifteen single cells, or at least twenty single cells, or at least twenty-five single cells, or at least thirty single cells, or at least fifty single cells, or at least one hundred single cells, or at least one fifty single cells.

[0162] The membrane 113 in the battery separates the anode 115 side and the cathode 112 side. The membrane 113 desirably prevents the crossover of active species in each half-cell and has high ionic conductivity, low area electrical resistance, and good chemical stability. The membrane in the battery can be an ion exchange membrane or a size exclusion membrane. In many embodiments, the membrane of the redox flow battery can be made from a non-fluorinated polymer. In some embodiments, the membrane can be made from hydrocarbon-based polymers including, but not limited to, polyethylene, polypropylene, polystyrene, and polyether ether ketone. These hydrocarbon-based membranes include non-fluorinated charge conducting groups including, but not limited to, ammoniated polystyrene, ammoniated polyether ether ketone, sulfonated polyether ether ketone, and sulfonated polystyrene. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Selemion TM is used. In certain embodiments, in a redox flow battery, as the cation exchange membrane, Selemion TM is used. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Fumasep TM FAA-3-20 is used. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Fumasep TM FAA-3-50 is used. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Fumasep TM FAS-30 is used. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Fumasep TM FAM-PP is used. In certain embodiments, in a redox flow battery, as the anion exchange membrane, Fumasep TM FAPQ-375-PP is used. In certain embodiments, in a redox flow battery, as the cation exchange membrane, Fumasep TM FKS-PK-75 is used. In certain embodiments, in a redox flow battery, as the cation exchange membrane, Fumasep TMUse FKS-50. In certain embodiments, in a redox flow battery, use Fumasep as the cation exchange membrane TM E620K.

[0163] In many embodiments, the anolyte 114 can include a compound having a perylene diimide moiety, and the perylene diimide moiety includes at least two ionic groups. The compound containing the perylene diimide moiety can be water-soluble. The ionic group can be a cationic group or an anionic group. The compound containing the perylene diimide moiety can have any of the formulas described in this disclosure. The multiple ionic groups in the perylene diimide compound can reduce and / or eliminate crossover through the membrane.

[0164] In some embodiments, the catholyte 111 can include a compound having a ferrocene moiety, and the ferrocene moiety includes at least two ionic groups. The compound containing the ferrocene moiety can be water-soluble. The compound containing the ferrocene moiety can have any of the formulas described in this disclosure. The multiple ionic groups in the ferrocene compound can reduce and / or eliminate crossover through the membrane. The redox flow battery can have a perylene diimide-containing compound in the anolyte and a ferrocene-containing compound in the catholyte. [Examples]

[0165] Example 1: A first half-cell containing a first aqueous solution including a first electrode and an anolyte including a compound having a perylene diimide moiety, wherein the perylene diimide moiety includes at least two ionic groups, a second half-cell containing a second aqueous solution including a second electrode and a catholyte, and a separator interposed between the first half-cell and the second half-cell, wherein less than 0.05% of the concentration of the anolyte crosses over to the second half-cell through the separator and less than 0.05% of the concentration of the catholyte crosses over to the first half-cell through the separator, a redox flow battery.

[0166] Example 2: The redox flow battery according to Example 1, wherein the separator is a size exclusion membrane or an ion exchange membrane.

[0167] Example 3: The redox flow battery according to Example 1 or Example 2, wherein the separator is an anion exchange membrane or a cation exchange membrane.

[0168] Example 4: A redox flow battery according to any one of Examples 1 to 3, wherein a concentration of less than 0.001% of the anode liquid crosses over to a second half-cell via a separator, and a concentration of less than 0.001% of the cathode liquid crosses over to a first half-cell via a separator.

[0169] Example 5: The compound is of formula (I) [ka] or having a salt thereof, T is -(LG) n -X is, T' represents H, (C1-C6) alkyl, or -(LG) n -X is, L is a -(C2-C5)-alkyl group, optionally substituted with OH, OCH3, or halogen. [ka] And, Each X is independently H, -(C1-C 10 ) alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1 These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p-O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. n=2 to 8, A redox flow battery according to any one of Examples 1 to 4, wherein p = 3 to 20.

[0170] Example 6: T and T' are each independently -(LG) n -X, a redox flow battery according to any one of Examples 1 to 5.

[0171] Example 7: A redox flow battery according to any one of Examples 1 to 6, wherein L is selected from the group consisting of unsubstituted -(C2-C5)-alkyl, ethyl, and propyl.

[0172] Example 8: A redox flow battery according to any one of Examples 1 to 7, wherein n is 2, 3, or 4.

[0173] Example 9:G is, [ka] The redox flow battery described in any one of Examples 1 to 8.

[0174] Example 10: A redox flow battery according to any one of Examples 1 to 9, wherein X is H, methyl, or -CH2CH2OH.

[0175] Example 11: A redox flow battery according to any one of Examples 1 to 10, wherein each X is independently H or -(C1-C6)-alkyl.

[0176] Example 12: A redox flow battery according to any one of Examples 1 to 11, wherein at least one X is -CH3CH2OH.

[0177] Example 13: The compound of formula (I) is [ka] [ka] [ka] [ka] [ka] [ka] The redox flow battery described in any one of Examples 1 to 12.

[0178] Example 14: The compound is of formula (II) [ka] It has, Each Y is independently -O-, -S-, or -NH-. Each q is independently between 1 and 8. Each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. A redox flow battery according to any one of Examples 1 to 13, wherein each V is a counterion.

[0179] Example 15: The compound of (II) is [ka] The redox flow battery described in any one of Examples 1 to 14.

[0180] Example 16: The compound is of formula (III) [ka] It has, Each X is independently H, -(C1-C 10 )-alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, and -(C1-C6)alkoxy, each of which is unsubstituted or independently selected with 1, 2, or 3 R 1 It is substituted with the base, Each R 1These are independently -OH, -O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl, -O(C1-C6)-alkyl-O(C1-C6)-alkyl-O(C1-C6)alkyl, -[O(C1-C6)-alkyl] p -O(C1-C6), -O(C=O)(C1-C6)alkyl, -O(C=O)O(C1-C6)alkyl, -O(C=O)OH, -O(C=O)NH2, -O(C=O)NH(C1-C6)alkyl, O(C=O)N[(C1-C6)alkyl]2, -NH(C=O)(C1-C6)alkyl, N(C1-C6)alkyl(C=O)(C1-C6)alkyl, halogen, -CN, -NO2, NH2, NH(C1-C6)alkyl, and N[(C1-C6)alkyl]2. Each s is independently between 2 and 4. Each R is independently H, -CH2OH, -CH2CH2OH, -CH2CH2OCH2CH2OH, or -CH2CH2OCH2CH2O(C1-6)alkyl. Each V - A redox flow battery according to any one of Examples 1 to 15, wherein is a counterion.

[0181] Example 17: The compound of formula (III) is [ka] [ka] The redox flow battery described in any one of Examples 1 to 16.

[0182] Example 18: The compound is of formula (IV) [ka] It has, R is [ka] [ka] [ka] The redox flow battery described in any one of Examples 1 to 17.

[0183] Example 19: The compound of formula (IV) is [ka] The redox flow battery described in any one of Examples 1 to 18.

[0184] Example 20: The compound is of formula (V) [ka] or having a salt thereof, L is -(C1-C6)-alkyl, Each G is [ka] And, A is a positive ion, A redox flow battery according to any one of Examples 1 to 19, wherein n=1 to 5.

[0185] Example 21: A redox flow cell according to any one of Examples 1 to 20, wherein L is replaced with OH, OCH3, and a halogen.

[0186] Example 22: A redox flow battery according to any one of Examples 1 to 21, wherein each A is lithium, sodium, potassium, or ammonium.

[0187] Example 23: Each G is, [ka] The redox flow battery described in any one of Examples 1 to 22.

[0188] Example 24: A redox flow battery according to any one of Examples 1 to 23, wherein each L is propyl.

[0189] Example 25: A redox flow battery according to any one of Examples 1 to 24, wherein n is 2.

[0190] Example 26: LG n The base is a redox flow battery according to any one of Examples 1 to 25, having at least one chiral center.

[0191] Example 27: A redox flow battery according to any one of Examples 1 to 26, wherein formula (V) has at least one stereoisomer.

[0192] Example 28: The compound of formula (V) is [ka] The redox flow battery described in any one of Examples 1 to 27.

[0193] Example 29: The compound of formula (V) is [ka] The redox flow battery described in any one of Examples 1 to 28.

[0194] Example 30: The compound of formula (V) is [ka] The redox flow battery described in any one of Examples 1 to 29.

[0195] Example 31: The compound of formula (V) is [ka] A redox flow battery according to any one of Examples 1 to 30, selected from the group consisting of any combination thereof.

[0196] Example 32: A redox flow battery according to any one of Examples 1 to 31, wherein A is lithium, sodium, potassium, or ammonium.

[0197] Example 33: The compound of formula (V) is [ka] The redox flow battery described in any one of Examples 1 to 32.

[0198] Example 34: A redox flow battery according to any one of Examples 1 to 33, wherein the cathode liquid comprises a second compound having a ferrocene moiety.

[0199] Example 35: The second compound is [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] A redox flow battery according to any one of Examples 1 to 34, having a formula selected from the group consisting of the following.

[0200] Example 36: The second compound is of formula (VI) [ka] It has, L is -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR 2 -(C1-C6)alkyl, or -(C1-C 10 )-alkyl-aryl, L' is -H, -(C1-C 10)-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C6)-alkyl-O(C1-C6)-alkyl, -(C1-C6)-alkyl-O-(C=O)-(C1-C6)alkyl, -(C1-C6)-alkyl-(C=O)-O-(C1-C6)alkyl, -(C1-C6)alkyl-NH-(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-NR 2 -(C=O)(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NH-(C1-C6)alkyl, -(C1-C6)alkyl-(C=O)-NR 2 -(C1-C6)alkyl, or -(C1-C 10 )-alkyl-aryl, G is [ka] Selected from the group consisting of, G is 2 or greater, A is Li, K, Na, or NH4. R 2 is, -(C1-C 10 )-alkyl, -(C1-C6)-alkenyl, -(C1-C6)-alkynyl, -(C1-C 10 A redox flow battery according to any one of Examples 1 to 35, wherein the element is )-alkyl-aryl, -aryl, or -(C=O)-(C1-C6)-alkyl.

[0201] Example 37: A redox flow cell according to any one of Examples 1 to 36, wherein L is substituted with at least one group selected from the group consisting of G, -OH, -OCH3, and -halogen.

[0202] Example 38: A redox flow cell according to any one of Examples 1 to 37, wherein L′ is substituted with at least one group selected from the group consisting of G, -OH, -OCH3, and -halogen.

[0203] Example 39: R 2A redox flow battery according to any one of Examples 1 to 38, wherein at least one G is replaced.

[0204] Example 40: LG n The redox flow battery according to any one of Examples 1 to 39, having at least one chiral center.

[0205] Example 41: A redox flow battery according to any one of Examples 1 to 40, wherein the compound has at least one stereoisomer.

[0206] Example 42: The compound of formula (VI) is [ka] The redox flow battery described in any one of Examples 1 to 41.

[0207] Example 43: The compound of formula (VI) is [ka] The redox flow battery described in any one of Examples 1 to 42.

[0208] Example 44: The compound of formula (VI) is [ka] The redox flow battery described in any one of Examples 1 to 43.

[0209] Example 45: The compound of formula (VI) is [ka] A redox flow battery according to any one of Examples 1 to 44, selected from the group consisting of any combination thereof.

[0210] Example 46: The compound of formula (VI) is [ka] The redox flow battery described in any one of Examples 1 to 45.

[0211] Example 47: A redox flow battery according to any one of Examples 1 to 46, wherein the anode liquid is perylenediimide-diammonium-Cl2 and the cathode liquid is ferrocene-diammonium-Cl2.

[0212] Example 48: A redox flow battery according to any one of Examples 1 to 47, wherein the anodic acid is perylenediimide-diammonium-Cl2, and after cycling the redox flow battery for at least 90 days, a concentration of less than 0.0004% of the anodic acid crosses over to a second half-cell via a separator.

[0213] Example 49: A redox flow battery according to any one of Examples 1 to 48, wherein the cathode liquid is ferrocene-diammonium-Cl2, and after cycling the redox flow battery for at least 90 days, a cathode liquid concentration of less than 0.02% crosses over to the first half-cell via the separator. [The doctrine of equivalence]

[0214] As can be inferred from the above discussion, the above-mentioned concepts can be implemented in various configurations according to the embodiments of the present invention. Therefore, although the present invention has been described in specific specific aspects, many additional modifications and variations will be apparent to those skilled in the art. Accordingly, it should be understood that the present invention can be implemented in ways other than those specifically described. In other words, the embodiments of the present invention are merely illustrative and should not be considered limiting.

[0215] As used herein, the singular terms "a," "an," and "the" may refer to multiple subjects unless otherwise specified. When referring to a subject in the singular form, unless explicitly stated otherwise, it should be understood to mean "one or more" rather than "a single" subject.

[0216] As used herein, the terms “approximately” and “about” are used to describe and account for small variations. When used with an event or situation, these terms may refer to both instances where the event or situation occurs exactly and instances where it occurs approximately. When used with a number, these terms may refer to a range of variation of that number of ±10% or less, for example, ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.1%, or ±0.05%.

[0217] In addition, quantities, ratios, and other numerical values ​​may be presented in range form in this specification. Such range forms are used for convenience and conciseness and should be flexibly understood to include not only the numerical values ​​explicitly designated as limits of the range, but also all individual numerical values ​​or subranges contained within that range, as if each numerical value and subrange were explicitly defined. For example, a ratio expressed in the range of about 1 to about 200 should be understood to include not only the explicitly listed limits of about 1 and about 200, but also individual ratios such as about 2, about 3, and about 4, as well as subranges such as about 10 to about 50 and about 20 to about 100.

Claims

1. Redox flow batteries including the following: A first-phase cell comprising a first aqueous solution containing a first electrode and an anode liquid containing a compound having a perylenediimide moiety, wherein the perylenediimide moiety contains at least two ionic groups; It includes a second electrode, a second aqueous solution containing a cathode solution, and a separator interposed between the first and second half-cells; Here, less than 0.05% of the anode liquid concentration crosses the separator to form a second half-cell, and less than 0.05% of the cathode liquid concentration crosses the separator to form a first half-cell.

2. The redox flow battery according to claim 1, wherein the separator is a size exclusion membrane, an ion exchange membrane, an anion exchange membrane, or a cation exchange membrane.

3. A redox flow cell according to claim 1, wherein less than 0.001% of the concentration of the anode liquid crosses the separator and reaches the second half-cell, and less than 0.001% of the concentration of the cathode liquid crosses the separator and reaches the first half-cell.

4. The redox flow battery according to claim 1, wherein the compound has formula (I): [Case 1] Examples include: or a salt thereof: T is -(LG) n -X; T' is H, (C 1 -C 6 ) Alkyl, or -(LG) n -X; L is -(C 2 -C 5 )-alkyl, with optional OH, OCH 3 , replaced by halo [Case 2] Each X is independently H, -(C 1 -C 10 )alkyl, -(C 2 -C 6 )alkynyl, -(C 2 -C 6 )alkynyl, and -(C 1 -C 6 )alkoxy group, each of which is substituted with 1, 2, or 3 independently selected R 1 groups; Each R 1 is OH, C 1 -C 6 -O(, -O(C=O)OH, -O(C=O)NH 2 , -O(C=O)NH(C 1 -C 6 ))-alkyl,-O(,-CN,-NO 2 NH 2 , NH(C 1 -C 6 ))-alkyl,-O(C 1 -C 6 )-alkyl,-O(C 1 -C 6 )-alkyl-O(C 1 -C 6 )-alkyl,-O(C 1 -C 6 )-alkyl,-[O(C 1 -C 6 )-alkyl)-alkyl,-O(C 1 -C 6 )-alkyl,-O(C 1 -C 6 )-alkyl-alkyl,-O( p -O(C 1 -C 6 ), -O(C=O)(C 1 -C 6 ))-alkyl, -O(OOI)-alkyl, -O(C=O)O(C 1 -C 6 )alkyl, O(, -CN, -NO 2 NH 2 , NH(C 1 -C 6 ))N[(C 1 -C 6 )alkyl] 2 , -NH(C=O)(C 1 -C 6 ), N(C 1 -C 6 ) alkyl; n = 2 to 8; and p = 3 to 20.

5. T and T' are independent of each other, -(LG) n A redox flow battery according to claim 4, wherein -X.

6. L is non-substituted (C 2 -C 5 A redox flow battery according to claim 4, comprising a group selected from the group consisting of alkyl, ethyl, and propyl groups.

7. The redox flow battery according to claim 4, wherein n is 2, 3, or 4.

8. G is; in the formula, X is H, methyl, -CH 2 CH 2 OH, or -(C 1 -C 6 A redox flow battery according to claim 4, wherein the battery is alkyl. [C3]

9. The redox flow battery according to claim 4, wherein the compound of formula (I) is: [C4]

10. The redox flow battery according to claim 1, wherein the compound has formula (III): [C5] Note X is independent of H, -(C 1 -C 10 )-alkyl,-(C 2 -C 6 )alkenyl, -(C 2 -C 6 )alkynyl, and -(C 1 -C 6 )alkoxy, each independently selected from R1, R2, or R3 1 A group and a group that is either non-substitutable or substituted; Each R 1 is OH, C 1 -C 6 -O(, -O(C=O)OH, -O(C=O)NH 2 , -O(C=O)NH(C 1 -C 6 ))-alkyl, -O(, -CN, -NO 2 , NH 2 , NH(C 1 -C 6 ))-alkyl, -O(C 1 -C 6 )-alkyl, -O(C 1 -C 6 )-alkyl-O(C 1 -C 6 )-alkyl, -O(C 1 -C N 6 )-alkyl, -[O(C 1 -C 6 )-alkyl)-alkyl, -O(C 1 -C 6 )-alkyl, -O(C 1 -C 6 )-alkyl-alkyl, -O( p -O(C 1 -C 6 ), -O(C=O)(C 1 -C 6 ))-alkyl, -O(OOI)-alkyl,,-O(C=O)O(C 1 -C 6 )alkyl, O(, -CN, -NO 2 , NH 2 , NH(C 1 -C 6 ))N[(C 1 -C 6 )alkyl] 2 , -NH(C=O)(C 1 -C 6 )、N(C 1 -C 6 )alkyl; s are independently 2 to 4; Each R is independently H, -CH 2 OH, -CH 2 CH 2 OH, -CH 2 CH 2 OCH 2 CH 2 OH, or -CH 2 CH 2 OCH 2 CH 2 O(C 1- 6) Alkyl, and each V - It is anti-on.

11. The redox flow battery according to claim 10, wherein the compound of formula (III) is: [6]

12. The redox flow battery according to claim 1, wherein the compound has formula (IV): [C7]

13. The redox flow battery according to claim 1, wherein the compound has formula (V): [C8] Examples include salts thereof. L is -(C 1 -C 6 )-alkyl; Each G is A is a cation, and n=1 to 5.

14. L is OH, OCH 3 , and replaced with a halo; where each A is lithium, sodium, potassium, or ammonium, the redox flow battery according to claim 13.

15. LG n The redox flow battery according to claim 13, wherein the group has at least one chiral center.

16. The redox flow battery according to claim 15, wherein formula (V) has at least one stereoisomer.

17. The compound of formula (V): [C9] The redox flow battery according to claim 13.

18. A redox flow battery according to claim 17, wherein A is lithium, sodium, potassium, or ammonium.

19. The redox flow battery according to claim 1, wherein the cathode liquid comprises a second compound having a ferrocene portion.

20. The redox flow battery according to claim 19, wherein the second compound has a formula selected from the group consisting of: [C10]

21. The redox flow battery according to claim 19, wherein the second compound has formula (VI): [Chem.11] Note L is -(C 1 -C 10 )-alkyl,-(C 1 -C 6 )Alkinel, -(C1-C6)-Alkinel, -(C 1 -C 6 )-alkyl, C 1 -C 6 -O(C 1 -C 6 )-alkyl,-(C 1 -C 6 )-alkyl-O-(C=O)-(C 1 -C 6 )-alkyl,-(C 1 -C 6 )-(C=O)-O-(C 1 -C 6 )-alkyl,-(C 1 -C 6 )alkyl, -(alkyl)alkyl, -(C 1 -C 6 ) Alkyl-NR 2 -(C=O)(C 1 -C 6 )alkyl, -(-NR 2 -(C=O)(C 1 -C 6 ))alkyl-(C=O)-NH-(C 1 -C 6 ), -(C 1 -C 6 )alkyl-(C=O)-NR 2 -(C 1 -C 6 ) or -(C 1 -C 10 It is an alkyl-aryl compound; L' is -H, -(C 1 -C 10 )alkyl, -(C1)alkyl, -(C1-C1)-alkyl, -(C 1 -C 6 )-alkyl(C 1 -C 6 )-O(C 1 -C 6 )alkyl)-alkyl,-(C 1 -C 6 )-O-(C=O)-(C 1 -C 6 )-alkyl,-(C 1 -C 6 )-(C=O)-O-(C 1 -C 6 )-alkyl,-(C 1 -C 6 )alkyl, -(alkyl)alkyl, -(lkyl--NR 2 -(C=O)(C 1 -C 6 ), -(C 1 -C 6 )alkyl, -(C 1 -C 6 )-(C=O)-NR 2 -(C 1 -C 6 ) alkyl, or -(C 1 -C 10 It is an alkyl-aryl compound; G is selected from the group consisting of; [Case 12] g is 2 or greater; A is Li, K, Na, or NH 4 And R 2 ha-(C 1 -C 10 )-alkyl,-(C 1 -C 6 )-alkenyl, -(C 1 -C 6 )-alkynyl, -(C 1 -C 10 )-alkyl, -aryl, or -(C=O)-(C 1 -C 6 It is an alkyl group.

22. L is G, -OH, -OCH 3 Substituted by at least one group selected from the group consisting of , and -HALO; L' is G, -OH, -OCH 3 Substituted with at least one group selected from the group consisting of , and -halo; R 2 The redox flow battery according to claim 21, wherein at least one G is replaced by G.

23. The redox flow battery according to claim 21, wherein the compound of formula (VI) is [Chem.13]

24. The anodic solution is perylenediimide-diammonium-Cl 2 The cathode solution is ferrocene-diammonium-Cl 2 The redox flow battery according to claim 1.

25. The anodic solution is perylenediimide-diammonium-Cl 2 The redox flow battery according to claim 1, wherein after cycling the redox flow battery for at least 90 days, less than 0.0004% of the anodic acid concentration reaches the second half-cell across the separator.

26. The cathode liquid is ferrocene-diammonium-Cl 2 The redox flow battery according to claim 1, wherein, after cycling the redox flow battery for at least 90 days, less than 0.02% of the cathode solution concentration crosses the separator and reaches the first half of the battery.

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