Method and apparatus for removing impurities from electrolyte

Abstract

To provide a method and an apparatus for reducing impurity levels in a battery system, an electrolyte solution obtained or obtainable from the method and apparatus, and a battery, an electrochemical cell and / or an electrochemical system, a fuel cell, an electrochemical storage system, and a redox flow battery and a flow battery system that includes the electrolyte.SOLUTION: A method for preparing an electrolyte solution having a reduced impurity level includes: a step a of electrochemically reducing an impurity present at an initial concentration in an initial electrolyte solution further including a redox-active electrolyte at a concentration of at least 0.5 M under conditions sufficient to produce an electrochemically treated electrolyte solution containing a reduced form of the redox-active electrolyte and a reduced form of the impurity; and a step b of separating the reduced form of the impurity from the electrochemically treated electrolyte solution to obtain a final electrolyte solution containing the impurity having a final concentration that is lower than the initial concentration of the impurity.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure provides a method and apparatus for preparing an electrolyte containing an electrolyte comprising a redox active material; and purified electrolytes prepared therefrom.

[0002] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application is a continuation of U.S. Provisional Patent Application No. 62 / 749,455, filed October 23, 2018. No. 9, filed on Oct. 1, 2009, the entire contents of which are hereby incorporated by reference. [Background technology]

[0003] Arsenic, antimony, and other substances in redox flow battery systems and general battery systems Problems with certain impurities, including tin and other such metal-containing impurities, include: It is well known, for example, in U.S. Pat. No. 9,647,290 and U.S. Pat. No. 9,985 ,311 and U.S. Patent Application Publication No. 2018 / 0102561 disclose vanadium flow Issues related to arsenic, antimony, and germanium deposition from battery systems These materials, as well as those containing Cr, Mn, Fe, Co, Ni, Cu, Zn, and Mo, are discussed. It is necessary to maintain the levels of other metals and metalloids, including uranium, through the selection of raw materials. The following is stated.

[0004] U.S. Patent Application Publication No. 2010 / 0143781 and U.S. Patent Application Publication No. 2010 / 0 No. 261070 both address Hg in electrolytes for iron-chromium-based redox flow batteries. Describes problems with impurities of Ni, Co, and Cu, and does not recommend the use of zinc amalgam or other inorganic reduction agents. We are trying to address or avoid the problems associated with these substances by using original ingredients. The method appears to be applicable only to solutions of iron ions and chromium containing acids. Summary of the Invention [Problem to be solved by the invention]

[0005] Such systems, either vanadium-based or other systems involving more diverse chemistries, There are few general methods available that provide solutions, if any. This has not previously been a problem in chemistry involving metal-ligand coordination compounds as described herein. The topic of reducing these types of impurities in these compound systems has not been addressed. There is no description of how to do this.

[0006] The present application is directed to addressing these and other problems.

[0007] The present disclosure provides methods and apparatus for reducing impurity levels, as well as methods and apparatus derived therefrom. Obtained or obtainable electrolyte solutions, as well as batteries, electrochemical cells and and / or electrochemical systems, fuel cells, electrochemical storage systems, and redox flows -Related to batteries and flow battery systems. [Means for solving the problem]

[0008] Certain embodiments of the present disclosure provide for preparing electrolyte solutions having reduced impurity levels. 1. A method for producing a medicament for use in a pharmaceutical composition comprising: (1) An electrochemically treated electrode containing a reduced form of a redox-active electrolyte and a reduced form of an impurity. and subjecting the resulting mixture to an initial reaction, further comprising a redox-active electrolyte, under conditions sufficient to produce a redox-active electrolyte solution. and electrochemically reducing at least impurities present in the electrolyte solution at an initial concentration. , (2) Separating the reduced forms of impurities from the electrochemically reduced solution and to obtain a final electrolyte solution having a final concentration of impurities lower than the initial concentration of impurities in the The method optionally further comprises:

[0009] In some embodiments, the concentration of the redox active electrolyte in the redox active electrolyte solution is in the range of 0.5M to 5M, or any subrange thereof.

[0010] In certain embodiments, the concentration of impurities in the final electrolyte solution is: (i) Less than about 10 mg per liter of redox-active electrolyte solution (mg / L) More than 5mg / L of pre-defined impurities, less than 2.5mg / L, less than 1mg / L One or more redox-active electrolytes less than 500 μg per liter of solution (μg / L) The above predetermined impurities, less than 250 μg / L, less than 100 μg / L, less than 50 μg / L Less than about 40 μg / L, Less than about 30 μg / L, Less than about 20 μg / L, Less than about 10 μg / L one or more predetermined impurities at less than about 5 μg / L, or less than about 1 μg / L; Or, (ii) Approximately 10 mg ( [mg / mol]) of one or more predetermined impurities, less than 5 mg / mol, 2. Less than 5 mg / mol, Less than 1 mg / mol, Redox active in electrolyte solution One or more predetermined concentrations of less than 500 μg per mole of soluble electrolyte ([μg / mol]) Impurities, less than 250 μg / mol, less than 100 μg / mol, less than 50 μg / mol, Less than about 40 μg / mol, less than about 30 μg / mol, less than about 20 μg / mol, less than about 10 μg / mol One or more of the following: less than about 5 μg / mol, less than about 5 μg / mol, or less than about 1 μg / mol The specified impurities are included in the redox active electrolyte solution. In this case, this is less than 5 μg / L or less than 5 μg / mol for Sb and As, For Ge and Sn, it is less than 10 μg / L or less than 5 μg / mol. In this form, the impurities are antimony, arsenic, germanium, tin, or combinations thereof. In another embodiment, the impurities are also Hg, Cr, Mn, Fe, Co, Ni , Cu, Zn, or Mo.

[0011] The reduction impurities depend on the nature of the impurities, the nature of the electrolyte solution (e.g., the associated redox active material Depending on the pH and nature of the solution and the reducing conditions used, plating, deposition, or evaporation may occur. In certain aspects of these methods, the electrochemical The selective reduction is carried out at a redox potential more negative than the reduction potential of the impurity.

[0012] Reducible impurities, when reduced, result in volatile reduced impurities, e.g., As(AsH3), germane (GeH4), stannane (SnH4), or stibine (S In embodiments including one or more of bH3), an additional method is to use an electrochemically processed electrolytic The solid solution, (a) The electrochemically treated electrolyte solution is heated at a temperature in the range of, for example, 20°C to about 105°C. Heating, or (b) the electrochemically treated electrolyte solution or the electrolyte solution heated in step (a) purging or sparging with an inert gas such as nitrogen or argon; The method further comprises conditioning the hair with one or both of the following:

[0013] The heating step and the purging step can be performed separately, simultaneously, or sequentially. Operation is preferably enhanced with or without electrochemical reduction conditions present. The process may be carried out in such a way that reoxidation of reduced impurities at the selected temperature is minimized or avoided. .

[0014] Any or all of these preceding steps may be carried out after the electrolyte has already been incorporated into the battery, electrochemical cell and / or electrochemical systems, fuel cells, electrochemical storage systems, and redox flow batteries and While the method may be performed while deployed in a flow battery system, the preferred implementation is In some embodiments, these methods are used to simplify the operation of batteries, fuel cells, or flow batteries. , prior to transport into such systems, e.g., storage tanks or other containers. will be done.

[0015] These electrolyte solutions were handled and manipulated as described previously. In this case, the redox-active electrolyte is charged with its reduced form, but Preferably, after removing all reduced impurities, an additional step is carried out to remove the reduced redox. The active electrolyte may be at least partially discharged.

[0016] Therefore, additional embodiments may include reducing the redox active electrolyte in the final electrolyte solution. Such oxidation may include (i) using an oxidizing gas (ii) using an oxidizing agent such as hydrogen peroxide, for example, with air or a gas mixture containing oxygen; (iii) using chemicals, (iv) electrochemically, or (v) a combination thereof. Whatever method is chosen, the choice of oxidizing agent may be influenced by, for example, the introduction of other impurities. It should be understood that the integrity of the purified electrolyte solution should not be compromised.

[0017] These methods are generally applicable to most chemical systems, including vanadium or iron-chromium systems. redox-active metal-ligand coordination compounds as described elsewhere herein, Also applicable to systems containing organic redox active materials described elsewhere, or combinations thereof It is possible.

[0018] The disclosure also specifically relates to purified compositions obtained or obtainable from these methods. That is, and for the avoidance of doubt, the present disclosure does not Such electrolyte solutions include those compositions, whether or not they have been prepared by As an independent embodiment, impurity levels lower than those described elsewhere herein. The present invention further comprises a suitable redox active electrolyte material at a concentration of at least 0.7M having a The impurities as so defined are one or more of As, Ge, Hg, and Sb; / or Ag, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Ge, Ir, Mg, M n, Mo, Ni, Pb, Pd, Pt, Re, Ru, Sb, Sc, Sn, Sr, V, and Z In certain embodiments, these solutions may contain antimony, arsenic, germanium, One or more of ruthenium, tin, and / or tin are less than 5 μg / L or 5 μg / mol (redox active Contains at levels below 0.01% (redox-active electrolytes in the electrolyte solution).

[0019] Additionally, flow batteries containing one or more of the disclosed electrolytes are also within the scope of this disclosure. do.

[0020] Additional embodiments of the present disclosure provide methods for implementing these methods and producing these purified electrolyte compositions. These devices include those useful for producing cation exchange membranes. An electrochemical cell having isolated first and second half-cell chambers is a device comprising at least one (i) the first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity; a first electrode, preferably a carbon electrode, in contact with an aqueous electrolyte; and (ii) a second half-cell chamber containing a second electrode in contact with a second aqueous electrolyte; The second aqueous electrolyte contains aprotic cations at a concentration of at least 0.1 M. The second electrode preferably comprises nickel, such as Ni foam, or stainless steel. Mesh, stainless steel felt, Ni oxide, Ni hydroxide, Ni oxyhydroxide, or The present invention includes an apparatus including a catalyst for generating O2, which catalyst includes Ni-Fe oxide.

[0021] Additional embodiments include a first half-cell chamber and a second half-cell chamber separated by a cation exchange membrane. 1. An electrochemical cell comprising two half-cell chambers, (i) the first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity; A first electrode, preferably a carbon electrode, e.g., carbon cloth, carbon, in contact with the aqueous electrolyte. -Bonnfeld, or carbon paper, and (ii) the second half-cell chamber has a pH of at least 2 and a concentration of at least 0.1 M; a first aqueous electrolyte in contact with a second aqueous electrolyte comprising one or more salts having an aprotic cation of Two electrodes are provided, (iii) wherein the second electrode is a catalyst for generating O2, preferably platinum or cobalt. tin, iridium, iron, manganese, nickel, ruthenium, tin, or combinations thereof The electrochemical cell includes at least one of the above oxides, most preferably IrO2.

[0022] In yet another embodiment, the electrochemical cell comprises a first half-cell chamber separated by a membrane. a second half-cell chamber and a second half-cell chamber, wherein: (i) the first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity; a first electrode in contact with an aqueous electrolyte; and (ii) a second half-cell chamber containing a second electrode containing a catalyst for generating O2; The half-cell chamber does not contain (does not include) an aqueous electrolyte.

[0023] Yet another embodiment is the disclosed method comprising operating the disclosed electrochemical cell. a method for carrying out the method of the present invention, comprising: adjusting the concentration of reducible impurities in the first aqueous electrolyte to a predetermined value; under conditions sufficient to reduce the level of The electrochemical devices described herein can be operated by passing a sufficient current through the cell. and a method comprising:

[0024] This application is better understood when read in conjunction with the accompanying drawings, in which, by way of example, there is shown in part one embodiment of the subject matter. While exemplary embodiments are shown, the subject matter disclosed herein is not limited to the particular embodiments disclosed. The drawings are not necessarily drawn to scale. This is not the case. [Brief explanation of the drawings]

[0025] [Figure 1]This figure shows a dot plot of the percent arsenic removed versus the oxidation reduction potential (ORP) after charging negolyte. Above a certain solution potential, greater than 99% of the arsenic in solution was removed after conditioning, as measured by ICP-OES. Each point in Figure 1 represents an individual experiment in which the negative electrolyte was charged at a temperature of 45°C to the solution potential (vs. Ag / AgCl) indicated on the x-axis. The charged electrolyte was conditioned at 65°C for several hours while sparging with flowing nitrogen and subsequently discharged by heating to reflux under the same gas flow conditions. ICP-OES was used to analyze the arsenic content in the electrolyte. [Figure 2] 1 is a dot plot of arsenic concentration in charged negolite over a period of about 40 hours at 65° C. [Figure 3]Figure 3(A) illustrates several potential embodiments of a HERM device. Figure 3(A) illustrates a class of device configurations in which the second electrolyte is acidic and the membrane assembly includes a cation exchange membrane (CEM) with an accompanying non-conductive layer (NCL), as described in International Application PCT / US2018 / 054798 (incorporated herein by reference in its entirety, or at least with respect to the device design and operating conditions disclosed). Note that this embodiment injects protons (H+) into the redox electrolyte being processed (as shown here, but not limited to the use of metal-ligand coordination compounds including titanium), and the injection of protons lowers the pH of the electrolyte solution, as described elsewhere herein. Note further that the acidic second electrolyte of the electrode is shown as IrO2, as in the more general metal oxide electrode examples described elsewhere herein. Figure 3(B) illustrates a second class of device configurations, in which the alkaline nature of the second electrolyte allows for the use of a less expensive electrocatalyst (exemplified here as Ni). The presence and injection of alkali metal cations (exemplified here as a Na+ / K+ mixture) allows for electron injection without changing the pH of the redox electrolyte being processed. Figure 3(C) illustrates a third class of device configurations. In this design, a carbon anode containing an iridium oxide catalyst is used against a carbon cathode. The anode is separated from the cathode by two cation exchange membranes, forming a third compartment. In the third compartment, a strongly buffered alkaline solution converts the proton flow generated by the anode into a stream of alkali metal ions. This configuration prevents the proton flow from decomposing negolite, but requires a more complex cell design. [Figure 4] FIG. 1 shows the positive electrode described in Example 5 after electrochemical reduction. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present disclosure relates to an electrolyte solution (posolyte or negolyte or both) and In particular, the present disclosure relates to a method for preparing an electrolyte solution containing less than a predetermined threshold level. This invention relates to the preparation of electrolyte solutions containing impurities at levels

[0027] The present disclosure may be further understood by reference to the following detailed description taken in conjunction with the accompanying figures and examples. This disclosure can be more easily understood by referring to the following: The present invention is not limited to the specific products, methods, conditions, or parameters described and / or illustrated herein. The invention is not limited to the above embodiments, and the terminology used herein refers only to specific embodiments by way of example. The present disclosure is intended to be illustrative and not to limit any subject matter recited in the claims. Similarly, unless otherwise indicated, Any statements about mechanisms or modes of action or reasons for improvement are to be construed as illustrative only; This disclosure does not address the correctness or incorrectness of any such proposed mechanism or mode of action or reason for improvement. Therefore, it should not be restricted. Throughout this specification, detailed descriptions and embodiments include redox-active electrolyte solutions. A method for preparing an electrolyte solution having reduced impurities, an electrolyte solution having reduced impurities itself, and and electrochemical devices and methods using these electrochemical devices useful for carrying out the method. It is recognized that the methodology described or highlighted in any one of these categories may be used. The embodiments or detailed descriptions used to identify them refer to all of these categories. That is, the present disclosure should be construed as including a system or apparatus or Describes features or embodiments related to methods of preparing or using the system or device and / or claims, if any, in such detailed description and / or claims. The scope of these features or embodiments is defined in each of these contexts (i.e., systems, It is understood that the present invention is intended to extend to embodiments of the present invention (apparatus, methods, and compositions).

[0028] Certain features of the invention are described herein in the context of separate embodiments for clarity. It should also be understood that features may be provided in combination or in a single embodiment. That is, unless clearly contradicted or specifically excluded, It is contemplated that any embodiment may be combined with any other embodiment(s). and such combinations are considered separate embodiments. Conversely, for the sake of brevity, Various disclosed features that are described in the context of a single embodiment may also be used separately or in any subcombination. Finally, the embodiments may be provided as part of a series of steps or more generally. Although each of the steps above may be described as part of a single structure, each step may be considered an independent embodiment in itself. It can also be considered as a process or can be combined with other processes.

[0029] Where a list is given, unless otherwise indicated, each individual element of the list and all combinations of that list should be understood to be separate embodiments. For example, a list of embodiments shown as "A, B, or C" may be changed to "A," "B," "C", "A or B", "A or C", "B or C", and "A, B, or C" implementations should be interpreted to include the state.

[0030] The present disclosure provides, among other things, several methods for reducing unwanted impurities from redox active electrolytes. In some cases, some impurities may be reduced to low mg / L or mg / mol levels, or even μ Electrochemical methods and apparatus capable of reducing the level of g / L or μg / mol The present disclosure also relates to electrolyte compositions having such reduced impurity levels, and and redox batteries containing such electrolytes.

[0031] [General method description] Therefore, certain embodiments of the present disclosure provide electrolytes with reduced impurity levels. A method for preparing a solution containing a reduced form of a redox active electrolyte and a reduced form of an impurity, under conditions sufficient to produce an electrochemically treated electrolyte solution having a redox activity The impurities present in the initial concentration in the initial electrolyte solution, including the electrolytic electrolyte, are removed by at least electrolytic In a related embodiment, the method comprises chemically reducing The reduced form of the impurity is separated from the chemically treated solution to obtain an impurity solution having a lower concentration than the initial concentration of the impurity. It may further include obtaining a final electrolyte solution having a pure final concentration.

[0032] These methods involve electrochemically reducing impurities to produce reduced forms of the impurities. In some embodiments, the electrochemical reduction can be carried out in an electrochemical cell using the skills of one of ordinary skill in the art. Impurities can be soluble in the electrolyte or can be solid in the redox-active electrolyte. Those skilled in the art, using their skills and the teachings herein, can readily determine the electrochemical Generally, electrochemical reduction involves applying a current to an electrolyte solution. If desired, reduction is carried out by passing an acid with a more negative potential than the reduction potential of the impurity. The required oxidation / reduction potential is determined by the amount of impurities removed from the electrolyte. The selection is based on the object.

[0033] "Electrolyte," "Redox-active electrolyte," "Impurity," and "Reduced form of impurity" A discussion of the intended meaning of terms is provided elsewhere in this specification. The method involves preparing an initial electrolyte solution containing impurities and redox-active electrolytes, which is then mixed with the specific redox active electrolyte used. It has a pH that makes it alkaline, neutral, or acidic, which is a characteristic that describes the properties of the active electrolyte. This rule is applicable whether or not a

[0034] Obviously, the nature and initial concentration of the impurities will depend on the redox conditions used in formulating the initial electrolyte solution. The active material depends on the nature and concentration of the electrolyte and other materials. For example, vanadium-containing electrolytes , Sb, As, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, or Sn, etc. These same types of impurities are known to occur in other metal-containing redox In other embodiments, the impurities may be antimony, Contains one or more forms of arsenic, germanium, mercury, tin, or combinations thereof.

[0035] In some of these embodiments, a redox active electrolyte, particularly a metal or metalloid, The concentration of the redox active electrolyte containing is at least 0.5M. The concentrations expressed in are described elsewhere herein in the context of the final redox active electrolyte solution. It has been done.

[0036] The method described herein allows the final concentration of impurities in the final electrolyte solution to be determined at a predetermined concentration. For example, in some embodiments, the final electrolyte The final concentration of impurities in the solution can be any of the impurity levels described herein. In a preferred embodiment, these impurity levels are defined in terms of: (i) less than about 50 μg of impurities per liter of final electrolyte solution, preferably less than 10 μg / liter less than 1 μg / L, more preferably less than 5 μg / L, and even more preferably less than 1 μg / L; Or, (ii) Approximately 50 μg per mole of redox-active electrolyte in the final electrolyte solution (μg / m impurities less than 10 μg / mol, more preferably less than 5 μg / mol less than 1 μg / mol, and even more preferably less than 1 μg / mol. These levels were achieved for various impurities using For example, the method can detect levels of less than 10 μg / L or less than 10 μg / mol. Ruthenium and / or tin at levels less than 10 μg / L or less than 10 μg / mol , and / or arsenic at levels less than 5 μg / L or less than 5 μg / mol, and / or 5 Antimony at levels less than μg / L or less than 5 μg / mol, and / or 5 μg / L or 5 μg / mol of mercury, and the final electrolyte solution Of course, as described elsewhere herein, the method may involve the use of higher The final electrolyte solution may contain one or more of these impurities at levels may contain

[0037] in removing impurities and reducing their initial levels to a final, predetermined level. The methods can also be characterized by their efficiency. So the final impurity levels are a 50% reduction of impurities relative to their initial levels. In another independent embodiment, the method comprises: at least 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 99.9% % lower final redox active electrolyte solution.

[0038] In some embodiments, the reduced form of the impurity is plated on or in the positive electrode of the electrochemical cell. When separated by, the impurities are removed or their concentration is reduced. In this case, the reduction products of impurities precipitated from the electrochemically treated electrolyte solution are Once precipitated, the impurity reduction product can be filtered, decanted, or otherwise removed from the solution. The precipitated impurities can be removed by known methods. The starting material is removed by flocculation, sedimentation, filtration, or membrane separation. The reduced forms of the impurities are removed by filtration. The quality is measured, for example, by filtering the chelating resin or by using a column packed with chelating resin beads. This can be done by passing the

[0039] In another embodiment, the nature of the impurity is that the reduced form of the impurity is a volatile hydride. In particular, this class of impurities includes volatile hydrides such as arsine (AsH3 ), germane (GeH4), stannane (SnH4), or stibine (SbH3) , for example, antimony, arsenic, germanium, or tin.

[0040] Clearly, for electrochemical reduction to be effective, it must be carried out in a redox-active electrolyte. In the presence of impurities, the reaction is carried out at a redox potential more negative than the reduction potential of the impurity. Therefore, a person skilled in the art should select an appropriate reduction potential for the target impurity. For this purpose, insofar as the impurities are reduced, they are directly reduced under the conditions in which they are applied. It is important whether the redox-active material is directly or indirectly reduced from the reduced form of the redox-active material (or vice versa). The presence of a predetermined redox-active electrolyte does not affect the reduction potential of the impurity. may be obtained, but to a first approximation, this is independent of the presence of redox-active electrolytes. In addition, the reduction potential of the impurity can be determined or is known, and for this reason, the exact reduction potential can be calculated. It is well within the ability of a person skilled in the art to determine the pH of a standard reduction potential. The effects are known, and again, one skilled in the art will be able to determine the appropriate potentials to apply to bring about the desired transformation. could be predicted accurately.

[0041] Particularly when the treatment results in the formation of volatile reducing impurities such as volatile hydrides. When produced in a large vessel, further processing helps remove the volatiles. Such a "conditioning" step may involve the electrochemically treated electrolyte. The solution is heated to ambient temperature up to the boiling point of the electrochemically treated electrolyte solution or the final electrolyte solution. This may involve heating under inert atmosphere conditions at temperatures above 1000 K. In this system, the boiling point of the final electrolyte solution is about 105°C to 110°C. In some embodiments, such heating is performed at temperatures between 20°C and 25°C, between 25°C and 30°C, or between 30°C and 40°C. ℃~35℃, 35℃~40℃, 40℃~45℃, 45℃~50℃, 50℃~55℃, 55 ℃~60℃, 60℃~65℃, 65℃~70℃, 70℃~75℃, 75℃~80℃, 80 ℃~85℃, 85℃~90℃, 90℃~95℃, 95℃~100℃, 100℃~105℃ or 105°C to 110°C, for example, 35°C to 95°C, more preferably 45°C to 85°C. In the case of aqueous systems, the temperature of the electrolyte may be within the range of 100°C to 120°C. Increasing the temperature promotes oxidation of charged redox-active electrolyte or reduced impurities, resulting in It is further understood that hydrogen may be generated as a result of oxidation. The temperature should be chosen so that the electrolyte remains charged (e.g., and / or to prevent the oxidization of fugitive hydrides to a soluble, non-volatile state). Alternatively or additionally, the operator may, during the heating process, subject the electrolyte solution to a suitable potential (i.e. , impurities and / or redox-active electrolyte) can.

[0042] In addition to or instead of heating, such a "conditioning" step may involve the use of an electric The electrolytic solution that has been gas-chemically treated or heated is filled with an inert gas such as nitrogen or argon. This may include purging or sparging with an active gas. It is important to maintain the volatile form. Purging also helps remove the reduced forms of impurities. This can be done using sufficient speed mixing. We have found that purging, optionally with mixing, can be , facilitating efficient transfer of the reduced forms of dissolved impurities to the gas phase and removal from the electrolyte. We found that...

[0043] If applicable, heating and / or sparging may be performed simultaneously through one or more cycles. Or they may be performed sequentially.

[0044] At least a portion of the reduced forms of the impurities are removed, resulting in an appropriate level of impurities in the final electrolyte solution. At the appropriate level, the redox active material will likely be in its fully reduced / charged state. For safety reasons or any other reason (e.g. during transport of the final electrolyte solution) of the final electrolyte solution, regardless of whether Decrease the state of charge (i.e., at least partially discharge the redox-active electrolyte) ) may be desirable. This can be achieved by any suitable oxidation method. For example, this can be done chemically by purging with air or an oxidizing gas such as oxygen. Hydrogen generation can be achieved by using chemical oxidizing agents such as hydrogen peroxide or electrochemically. Biocatalysts (e.g., activated carbon, carbon cloth, carbon felt, carbon paper, Ti Mesh, Ti felt, Ti foam mesh, Pt plated Ti mesh, or a combination of several of these methods. The reagent or method for such oxidation is preferably It is selected so that no harmful substances are introduced.

[0045] The oxidation can be carried out at ambient temperature or at reduced or elevated temperatures. In embodiments, the final electrolyte solution is heated at one or more temperatures of at least 65° C. or higher, preferably at a temperature of about 85°C or higher, more preferably at a temperature of about 105°C or higher, and the final electrolyte solution In certain circumstances, the application of heat and / or sparging may be useful. In some cases, it is used intentionally to control the redox activity in the final redox-active solution. The active electrolyte can be further concentrated.

[0046] [Electrochemical device (HERM device)] In this regard, the present disclosure provides electrolytes with reduced levels of these reducible impurities and impurities. While we have focused on methods of removal, this disclosure also provides methods useful for implementing these methods. This includes devices / systems.

[0047] To be operable, the chemistry must be at a potential sufficient to reduce reducible impurities. "Injecting" electrons into the electrolyte solution, i.e., into the electrolyte solution containing the redox active material The compensation cations (co) that must accompany the injected electrons are required. The effect or nature of the unbalancing cation has not been discussed. While doing so, the equipment / system used (hereinafter referred to as "HERM equipment" or hybrid electric The equipment is called the Hybrid Electrochemical Removal Modular device. The physical choice is to use an electrolyte that is "purified" (i.e., a redox active material that has been stripped of impurities). The choice of system depends on the state of charge of the redox active material and In both cases, the amount of impurity (whether interpreted as 100 mg / L or 100 ppm) is The redox active material in any practical electrolyte solution (typically greater than 0.5M) ) is very small compared to the amount of reducible impurities. A hypothetical electrolyte solution containing 1M redox-active material at 50% state of charge containing pure Consider a typical 1 liter solution. Almost all of the electrons injected into such a system It is used to reduce the redox active material, and only a small proportion is used to reduce the reducible impurities. The electrons required to reduce the state of charge of the redox active material are , which can be several orders of magnitude larger than the electrons required to reduce the reducible substance. In such a system, these electrons are accompanied by an equal number of compensating cations.

[0048] Perhaps more importantly, whether the electrolyte being treated is acidic or alkaline Regardless, implanting hydrogen ions at these levels generally results in Concentrations much higher than the hydrogen ion content of the electrolyte occur (even at pH = 2, [H + ]=0.01M). Such injections have a significant effect on the pH change of the treated electrolytes. This can be achieved by adjusting the pH of the electrolyte solution with a suitable base after the reduction step is complete. However, even the addition of a base can result in significant impurities in the purified electrolyte solution. A more sophisticated solution is to use alkali or alkaline earth metals. Use a HERM device to simultaneously inject metal (or other aprotic) cations with electrons. To do this.

[0049] Previously described devices for pH equilibration of systems include those described in WO 2015 / 04 This includes the devices described in application Ser. No. 8074 ('074), the contents of which are incorporated herein by reference. The '074 application is incorporated herein by reference for all purposes. The present invention teaches an apparatus and method for simultaneously balancing both the electron and proton content of a solution. As described therein, the device described as a rebalancing cell or balancing cell is an electronic and proton pump. This paper describes an apparatus and method for injecting both ammonium hydroxide and ammonium hydroxide into a redox-active electrolyte solution. Although it is described as being attached to a flow battery, this description is not intended to be a stand-alone The rebalancing cell is also described as a standalone device. Some embodiments described herein include those in which the balance cell comprises: . (1) a first half-cell chamber and a second half-cell chamber, a first electrode in contact with a first aqueous electrolyte of a redox flow battery; The battery chamber includes a second electrode in contact with a second aqueous electrolyte, the second electrode being O 2. In some of these embodiments, the second aqueous electrolyte The pH is at least 2, preferably greater than about 7, and more preferably in the range of about 9 to about 14. In other embodiments, no second electrolyte is added. (2) a first electrode in contact with a first aqueous electrolyte of a redox flow battery; a second half-cell comprising a second electrode in contact with the second aqueous electrolyte; a chamber, wherein the second electrode is a sacrificial electrode that generates O2 and / or CO2. The two half-cell chambers are separated by an ion-exchange ionomer membrane. It is being done. (3) a first electrode in contact with a first aqueous electrolyte of a redox flow battery; a half-cell chamber and a second electrode containing a catalyst for generating O2, and a second half-cell chamber that is not in contact with the aqueous electrolyte. are separated by an ion-exchange ionomer membrane.

[0050] In these embodiments, the first aqueous electrolyte is the negative working electrolyte of the redox flow battery. ("Negolite"). In various embodiments, the compound is at an acidic or neutral pH value. The electrochemistry associated with the second half-cell of the balanced cell is given by equation (1): 2H2O → 2O2 + 4H + +4e - ·····(1) At more basic pH values, the electrochemical reaction associated with the second half-cell of the equilibrium cell The study is based on the equation (2): 4OH - →2H2O+O2+4e - ·····(2) It is described by:

[0051] The corresponding electrochemical reactions associated with the first half-cell are shown in equations (3)-(5): M n +e - →M n-1 (3) and IMP n+ +ne - →IMP 0 (4) or IMP n+ +ne - +nH + →IMP.H n ···(5) It can be written as: where, M n and M n-1 are the oxidation states of redox-active species in negolite, respectively. In this application, the redox active material in the solution being treated corresponds to the form and reduced form. So, "IMP n+ " is the initial form of the impurity (e.g., As 3+ ) and IMP 0 and I MP·H n refers to the reduced metal or hydride form of the impurity, respectively. In this context, two such reaction schemes are shown in equations (6) and (7): As+3H + +3e - →AsH3········(6) As+3H2O+3e - →AsH3+3OH - ···(7) It can be understood as follows.

[0052] The '074 application is directed to the simultaneous balancing of the electron and proton content of a working electrolyte solution. In both situations, the second half-cell of the pH compensation cell is connected to the first half-cell through the membrane. It is said that the transport of protons through the ion exchange provides charge balance to negolite. As a result of this study, the '074 application proposes that the second half-cell chamber be heated in an alkaline environment. Two half-cell chambers, where a second electrode containing an activated O2 generating catalyst is provided. However, one cation exchange ionomer membrane and one metal oxide membrane sandwiched between them promotes water dissociation. It is described that the particles are separated by a bipolar membrane consisting of two anion exchange ionomer membranes. The use of a bipolar membrane distributes alkaline electrolyte in the second half-cell chamber. Operating the balance cell while opening is described.

[0053] However, in this case, for the reasons stated above, Injecting electrons and protons simultaneously is less desirable, and electrons and other non-protons It is more desirable to simultaneously inject the ionic cations into the electrolyte solution. Therefore, alkali metal cations or alkaline earth metal cations (or even ammonia) (aluminum cations) to prevent the need for pH adjustment of the first aqueous electrolyte after electrochemical treatment. By incorporating it into the second electrolyte in a concentration sufficient to reduce the The device can be reconfigured to inject electrons and aprotic cations simultaneously. do. In a preferred embodiment, the alkali metal cation or alkaline earth metal in the second electrolyte The cation (or even the ammonium cation) is much larger (e.g., the second charge More than 10 times, 100 times, 500 times, 1000 times, 500 times, or more than the concentration of protons in the solution In certain embodiments, these The aprotic cation is an alkali metal cation or an alkaline earth metal cation, e.g. Ba, Li + , Na + , K. + , [NH n R 4-n ] + (R=alkyl), or a mixture thereof These aprotic cations can be present in the second aqueous electrolyte at a concentration of at least 0. In the concentration range from 1M to their saturation concentration, or 0.1M to 0.2M, 0.2M to 0. 3M, 0.3M~0.4M, 0.4M~0.5M, 0.5M~0.6M, 0.6M~0. 7M, 0.7M~0.8M, 0.8M~0.9M, 0.9M~1M, 1M~1.25M, 1.25M to 1.5M, 1.5M to 2M or more, or any of the above ranges Exemplary counterions to these cations include hydroxide, iodide, and iodine. ions, phosphate ions, or sulfate ions.

[0054] In this case, a system similar to the system described in the '074 application (including its hardware) and (including embodiments thereof) as a HERM device, using a flow current as described in the '074 application. Attached to a pond or attached to a storage tank or container and / or from a working system The HERM device can be used separately or in combination with a working flow battery system. Since no HERM device is used, the voltage and other efficiencies of such a flow battery system is not important to the economics of

[0055] In certain embodiments of the present invention, the electrochemical cell comprises a first semi-conductor separated by a membrane. a first half-cell chamber and a second half-cell chamber, wherein the first half-cell chamber is a first aqueous electrolyte containing a catalytically active electrolyte (e.g., negolite) and reducible impurities; A first electrode, preferably a carbon electrode, such as carbon cloth or carbon ferrite, is in contact with the The second half-cell chamber is preferably acidic and contains either teflon or carbon paper. a second electrode in contact with a second aqueous solution having a pH of at least 2; The second electrode contains a catalyst for generating O2, preferably platinum, cobalt, or iridium. a small amount of oxides of iron, manganese, nickel, ruthenium, tin or a combination thereof At least one, most preferably IrO2.

[0056] In that regard, in other embodiments, the present disclosure provides a first half-cell chamber and a second half-cell chamber separated by a membrane. and a second half-cell chamber, wherein the first half-cell chamber is a red a first electrode in contact with a first aqueous electrolyte containing a catalyst active material and reducible impurities; a second half-cell chamber in contact with a second aqueous solution, preferably comprising a carbon electrode; a second electrode made of nickel, preferably nickel foam, such as Ni foam; Stainless steel mesh, stainless steel felt, Ni oxide, Ni hydroxide, Ni o An electrochemical cell containing an O2-generating catalyst including Ni-Fe hydroxide or Ni-Fe oxide is also provided. To plan.

[0057] In some of these embodiments, the membrane is a cation exchange membrane (“CEM”). In embodiments, the membrane is not a bipolar membrane as described in the '074 application, but rather an integrated This does not include anion exchange membranes. Materials useful for these cation exchange membranes include, optionally, perfluorinated perfluoro-containing copolymers of tetrafluoroethylene with polyvinyl ethers; Sulfonic acid membrane or polyfluorosulfonic acid membrane (NAFION® membrane, AQUIV ION (registered trademark) membrane, or FLEMION (registered trademark) membrane), sulfonated hydrocarbon membrane ( sulfonated polyether ether ketone, sulfonated polyphenylsulfone) Other exemplary perfluorinated membrane materials include tetrafluoroethylene and one or more fluorinated Other useful perfluorinated electrolytes include copolymers of tetrafluoroethylene and tetrafluoroethylene copolymers of tetrafluoroethylene copolymers. Trifluoroethylene (TFE) and FSO2-CF2CF2CF2CF2-O-CF=C Contains copolymers of F2.

[0058] In some embodiments, the second aqueous electrolyte does not contain a redox active material. In embodiments, the second aqueous electrolyte is a lecithin, as discussed elsewhere herein for this purpose. Preferably, the aprotic cations of the second solution are The type and proportion of amines are approximately the same as or similar to those of the electrolyte solution being treated (in the first half-cell). The term "almost identical" refers to the cation content in the redox-containing electrolyte. This refers to a distribution of cations that does not require adjustment after treatment. The mobility of each cation through the membrane is , the relative proportions of cations in the second electrolyte solution are compared to the corresponding proportions in the treated electrolyte. The ability to determine these differences may be necessary, if necessary. This can be determined by one of ordinary skill in the art without undue experimentation.

[0059] In yet another independent embodiment, the pH of the first aqueous electrolyte and the second aqueous electrolyte are both Both are less than 7, both are about 7, or both are greater than 7. The device and method can be used to detect, for example, the presence of vanadium in a flow battery or an iron-chromium flow battery. and metal-ligand coordination compounds, e.g., titanium Negolite materials based on silane (and the broader range of negolites described herein) Alkaline or pH-neutral redox-active electrolytes based on HCl can be processed.

[0060] Preferably, the pH of the first aqueous electrolyte and the second aqueous electrolyte differ by less than 5 pH units. In other independent embodiments, the electrolyte is less than 4 pH units, less than 3 pH units, less than 2 pH units, unit, or differ by less than 1 pH unit. If higher, pH as described in filed international application PCT / US2018 / 054798 A buffer layer strategy can also be used.

[0061] As noted above, the second electrode generally includes a catalyst that generates O2. In some cases, the second electrode is a metal oxide catalyst suitable for electrochemically generating O2 from water. In addition to their ability to generate O2, these oxidation catalysts preferably Is it corrosion resistant under the pH range considered, or is it a poor catalyst for reducing water to hydrogen? or both. The corroding catalyst crosses over to the first pH correction half-cell and This may interfere with the effectiveness of the flow battery, or even worse, interfere with the operation of the flow battery. Such a crossover catalyst is a highly efficient catalyst for hydrogen generation under reducing conditions in the first half-cell. When the catalyst is the first half-cell or the negative electrode of the working flow battery, hydrogen generation is a safety concern. One scenario could be envisioned that would raise concerns about: Thus, the present invention provides a method for producing a second electrode using cobalt, iridium, iron, manium, or other metals. Preferentially oxides of iron, nickel, ruthenium, tin, or combinations thereof are used. Due to its good catalytic activity for O2 evolution and high corrosion resistance, Iridium chloride is particularly preferred.

[0062] If the second half-cell chamber contains an alkaline electrolyte, it provides a good catalyst for O2 generation. Nickel oxide or nickel-iron oxide are preferred due to their catalytic activity and high corrosion resistance in bases. Catalysts are particularly preferred. Suitable materials in this case include Ni foam, stainless steel mesh, etc. , stainless steel felt, Ni oxide, Ni hydroxide, Ni oxyhydroxide, or Ni- Contains Fe oxide.

[0063] In some embodiments, the second electrode of the HERM device comprises carbon. It is well known in the art and may be graphitic carbon, glassy carbon, amorphous carbon, boron or nitrogen. Carbon doped with elements, diamond-like carbon, carbon onion, carbon nano including tubes, carbon cloth, carbon felt, carbon paper, and graphene. Carbon materials can generate O2 despite a somewhat high overpotential, but the carbon It is inevitable that the electrode itself will oxidize to CO2. In other embodiments, the second electrode may also be a Ti mesh, a T iFelt, expanded Ti mesh, stainless steel mesh, and stainless steel felt It may include

[0064] In yet another embodiment, the electrochemical cell comprises a first half-cell chamber separated by a membrane. and a second half-cell chamber, wherein (i) the first half-cell chamber contains a redox a first electrode in contact with a first aqueous electrolyte containing an active material and reducible impurities; and (ii) the second half-cell chamber comprises a second electrode including an O2-generating catalyst; And the second half-cell chamber does not contain (does not include) an aqueous electrolyte.

[0065] In this configuration, the water required for the O2 evolution reaction is transported across the membrane in the first half-cell. Provided by water from the aqueous electrolyte in the chamber. Avoid situations that restrict mass transport. Therefore, the transport of water across the membrane must be faster than the consumption of water by the metal oxide catalyst. The second half-cell chamber side of the membrane is coated with a metal oxide O2 evolution catalyst (e.g., IrO x ) is As a result, water transported across the membrane from the first half-cell chamber is directly This configuration greatly simplifies the design of electrochemical devices. For example, the metal oxide catalyst on the membrane can be directly connected to the titanium end plate, This eliminates the need for a titanium mesh to act as a flow field for the aqueous electrolyte. An additional design feature is a vent for molecular oxygen generated in the metal oxide catalyst. Furthermore, water was periodically added to the electrolyte tank for Negolite to replenish the water consumed in the O2 generation reaction. Optionally, this make-up water may be mixed with the generated O2 and HE from the second half-cell chamber. Occurs in the second half-cell chamber of the electrochemical cell of the RM device and in the negolite section of the first cell This water production process can be performed in situ by combining the hydrogen with the hydrogen. It can be catalyzed by a noble metal catalyst (eg, Pt, Pd, etc.).

[0066] Additional embodiments include methods of operating any of these HERM devices described herein. Each method comprises applying a potential across the first and second electrodes of the device. and applying an electric current to the device in the presence of the aqueous electrolyte to be treated. The specific conditions for such manipulation are described elsewhere in this specification. When operating to remove impurities from an electrolyte solution containing these redox active materials, Therefore, parasitic hydrogen generation does not interfere with its primary function. This allows the electrode to be constructed without stainless steel. Cheaper materials such as steel can be used.

[0067] Further embodiments include batteries, electrochemical cells, fuel cells, and / or flow batteries, e.g. Cell stack, storage tanks and piping to contain and transport electrolyte, control hardware and software software (which may include a safety system), and at least one power conditioning unit. This includes incorporating it as part of an energy storage system within a larger system that includes In such a system, the storage tank contains the electroactive material. The hardware, and any safety systems, shall be All sensors, mitigation devices and electronic / hardware components that ensure autonomous and efficient operation in the Includes software control devices and safety devices.

[0068] Such a storage system includes a power conditioning unit at the front end of the energy storage system. This allows the input and output power to be adjusted to the optimum voltage and voltage for the energy storage system or its application. In the example of a grid-connected energy storage system, the charging station In the cycle, the power conditioning unit adjusts the input AC electricity to the appropriate voltage and During the discharge cycle, the stack generates DC power. The power conditioning unit then converts the AC power to a voltage and frequency suitable for grid use. Such energy storage systems are well suited to sustained charge or discharge cycles of several hours. There are. Thus, the system smooths the energy supply / demand profile (e.g. Suitable for providing a stabilization mechanism for intermittent generating assets (from renewable energy sources) In doing so, various embodiments of the present invention are directed to providing a battery that can be used in applications where such long charge or discharge times are beneficial. It should be understood that this includes electrical energy storage applications where, for example, Non-limiting examples include applications where the system of the present invention is connected to the power grid, providing renewable energy. Electric grid integration, peak load shifting, grid farming, base load generation / consumption, energy Energy arbitrage, transmission and distribution asset deferral, weak grid support, and / or frequency Furthermore, the device or system can be used to, for example, as a power source for power plants, forward operating bases, off-grid telecommunications, or remote sensors To provide stable power for applications not connected to the power grid or microgrid can be done.

[0069] [Redox active electrolyte solution with reduced impurities] The present disclosure further embodies final electrolyte solutions that can be used in the disclosed methods. Embodiments are provided in which these electrolyte solutions are prepared ("obtained") by the methods disclosed herein. The redox active electrolytes and impurities disclosed herein, whether or not they are "prepared" (or "prepared"), As used herein, "obtained from" includes electrolyte solutions having impurity levels of The term "capable" means that a predetermined electrolyte solution can be prepared by the method of the present invention ( i.e., including the properties of the electrolyte solutions described herein), may in fact be used in alternative ways. This indicates that it was prepared.

[0070] These final "reduced impurity" electrolyte solutions contain at least one redox Active electrolyte, containing one or more impurities at levels described herein, and optionally, Depending on the desired performance, further additives (surfactants, viscosity modifiers, buffers, and non-redox The active molecule / electrolyte of the active species may be contained.

[0071] The selection of the at least one redox active material is flexible, e.g., vanadium, iron, chromium, These latter types of materials include the salts of chromium, or various metal-ligand coordination compounds. In particular, the present disclosure provides methods and resulting redox The authors emphasize the usefulness of an active electrolyte solution, where the redox active material is, in particular, negolite. Examples include metal-ligand coordination compounds containing titanium.

[0072] In the inventors' experience with bulk commodity chemicals, significant impurities are found in the raw materials. This typically corresponds to impurities in the final bulk formulated electrolyte. Pharmaceuticals are a common source of impurities. Some typical impurities from common precursor materials: The ranges of these impurities are shown in Tables 1A and 1B below. Depending on the method used, It accumulates in the final flow battery electrolyte and can be found in high concentrations. See also Table 2 for comparable data for titanium-catecholate derivatives prepared from Please refer to.

[0073] For example, economical grade NaOH is used in the synthesis of organic redox active materials at a few equivalents. When such materials are used, the resulting material may be rich in impurities such as Ni. The combined electrolyte may be prone to increased precipitation or parasitic hydrogen generation in flow batteries. do.

[0074] JPEG2025121980000001.jpg73170

[0075] JPEG2025121980000002.jpg78170

[0076] JPEG2025121980000003.jpg54170

[0077] Impurities from the vanadium source can be even higher.

[0078] JPEG2025121980000004.jpg135170

[0079] These redox active electrolyte solutions, including those with reduced impurities, In the solution, the concentration of the at least one redox active material is at least 0.7M. In various embodiments, the concentration of the at least one redox active material is between 0.7M and 0.8M; 0.8M~0.9M, 0.9M~1M, 1M~1.2M, 1.2M~1.4M, 1.4M ~1.6M, 1.6M~1.8M, 1.8M~2M, 2M~2.2M, 2.2M~2.4 M, 2.4M~2.6M, 2.6M~2.8M, 2.8M~3M, 3M~3.5M, or The impurities in the final redox active solution are defined by one or more ranges between 3.5M and 4M. The levels of substances are only relevant in situations where these concentrations are actually useful (or higher), It should be interpreted in these circumstances.

[0080] Impurities are generally Ag, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, G e, Hg, Ir, Mg, Mn, Mo, Ni, Pb, Pd, Pt, Re, Ru, Sb, Sc , Se, Sn, Sr, Te, V, and Zn, but in certain implementations In some embodiments, the impurities are described as including one or more of As, Ge, Hg, and Sb.

[0081] In these circumstances, in some embodiments, the levels of these impurities are Based on the total mass of the active electrolyte solution (not the amount of redox active electrolyte in the solution). These may typically be specified in ppm or ppb terms. Alternatively, the level of impurities may be specified in The formula is, for example, a mg / L or μ / L basis, equivalent to a unit volume of redox active electrolyte solution. The density of the redox active electrolyte solution is 1 g / L. In some cases, the corresponding values for ppm to mg / L and ppb to μg / L are equivalent.

[0082] Thus, in an independent embodiment, the redox active electrolyte solution is One or more predetermined concentrations of less than about 10 mg per liter of electrolyte solution (mg / L) Impurities, one or more predetermined impurities less than 5 mg / L, one less than 2.5 mg / L or more predetermined impurities, less than 1 mg / L of one or more predetermined impurities, red One or more pre-mixed active electrolytes containing less than 500 μg per liter of solution (μg / L) Predefined impurities, one or more predefined impurities less than 250 μg / L, 100 μ g / L of a predetermined impurity, or one or more predetermined impurities less than 50 μg / L one or more predetermined impurities less than about 40 μg / L, one less than about 30 μg / L or more predetermined impurities, and one or more predetermined impurities less than about 20 μg / L; less than about 10 μg / L of one or more predetermined impurities, less than about 5 μg / L of one or more A predetermined impurity or one or more predetermined impurities less than about 1 μg / L Again, for clarity, these statements apply to each substance listed as an impurity. are intended to apply individually and independently of each other. For example, these stated ranges One specifically depicted composition, which specifies As, Sb, and Ge, is, for example, 5 may contain less than 10 μg / L of As, less than 10 μg / L of Sb, and less than 50 μg / L of Ge. do.

[0083] In some embodiments, the electrolyte solution contains less than about 50 μg / L of As, Ge, Hg, and In another preferred embodiment, the electrolyte solution contains one or more of Sb. Full of Ag, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Ge, Hg, Ir , Mg, Mn, Mo, Ni, Pb, Pd, Pt, Re, Ru, Sb, Sc, Sn, Sr, In a more preferred embodiment, the electrolyte solution contains one or more of: V, and Zn. Contains less than g / L of one or more of Sb, As, Ge, Sn, or a combination thereof. In other preferred embodiments, the electrolyte solution contains less than about 5 μg / L of As, Hg, or In an even more preferred embodiment, the electrolyte solution contains a combination of about 5 μg / In yet another preferred embodiment, the alloy contains less than L of Sb, As, or a combination thereof. In the present invention, the electrolyte solution contains less than about 10 μg / L of Ge, Sn, or a combination thereof. do.

[0084] However, the main source of incidental impurities is typically redox-active metals. The metal (e.g., vanadium) or redox-active metal-ligand coordination compound (e.g., These impurity levels are also (perhaps more appropriately) (especially) the amount of redox active electrolytes in the redox active electrolyte solution in terms of their mass In such cases, the relevant criteria may be defined as the amount of redox-active electrolyte solution. Parts by weight of impurities per mole of redox-active electrolyte in the solution (i.e., mg / mol Once again, the redox in the redox-active electrolyte solution is When the concentration of the active electrolyte is 1M, the values in mg / mol or μg / mol are It is numerically equivalent to ppm or ppb. However, in practice, additional embodiments may include: The impurity level is calculated based on the molar concentration of redox active electrolyte in the redox active electrolyte solution. Including embodiments described in terms of mg / L or μg / L (e.g., 0.8M redox The definition of 10 μg of impurity per active electrolyte solution / L (solution) is [10 μg / L] / [ 0.8 mol / L] or 12.5 μg impurities / mol (in redox-active electrolyte solution) redox-active electrolytes).

[0085] In this regard, in an independent embodiment, using a 1M basis, the redox active electrolyte solution is Approximately 10 mg per mol of redox active electrolyte in the redox active electrolyte solution (hereinafter, (expressed as mg / mol).) Less than 5 mg / mol per mole of redox-active electrolyte in the active electrolyte solution, 2.5 Less than mg / mol, Less than 1 mg / mol, Less than 500 μg / mol, 100 μg / mol less than, less than 50μg / mol, less than 40μg / mol, less than 30μg / mol, 20μg / mol, less than about 10 μg / mol, less than 5 μg / mol, or 1 μg / mol containing less than one or more predetermined impurities.

[0086] Similarly, in some embodiments, the electrolyte solution contains less than about 50 μg / mol of As, Ge In another preferred embodiment, the electrolyte solution contains one or more of: Less than 5 μg / mol of Ag, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Ge, Hg, Ir, Mg, Mn, Mo, Ni, Pb, Pd, Pt, Re, Ru, Sb, S In a more preferred embodiment, the electrolytic The substrate solution contains less than about 5 μg / mol of Sb, As, Ge, Sn, or a combination thereof. In another preferred embodiment, the electrolyte solution contains less than about 5 μg / mol In an even more preferred embodiment, the SiO2 solution contains: The electrolyte solution contains less than about 5 μg / mol of Sb, As, or a combination thereof. In yet another preferred embodiment, the electrolyte solution contains less than about 10 μg / mol of Ge, Sn or a combination thereof.

[0087] [Use of electrochemical (redox) systems with reduced impurities in electrolyte solutions] The redox active electrolyte solutions of the present invention may also be used in flow battery or fuel cell applications. Thus, the present disclosure provides the reduced impurity electrolyte solutions described herein. and flow batteries comprising at least one half-cell containing one of the It includes a system that includes:

[0088] [term] Throughout this specification, terms are used in the usual sense as understood by those skilled in the relevant art. However, to avoid misunderstandings, the meaning of certain terms should be Specifically define or clarify the following.

[0089] In this disclosure, unless the context clearly indicates otherwise, the singular forms "a," "an," and "a" are used interchangeably. and "the") also includes plural references, and a reference to a particular number includes at least that particular value. Thus, for example, a reference to "a material" includes reference to such material known to those skilled in the art. and equivalents thereof.

[0090] When a value is expressed as an approximation by use of the descriptor "about," that particular It will be understood that values form alternative embodiments. In general, use of the term "about" means to These represent approximations that may vary depending on the desired properties sought to be obtained by the disclosed subject matter. The term "component" should be interpreted based on its function in the specific context in which it is used. In some cases, the The number of significant digits in a range can be one non-limiting way of determining the scope of the term "about." In this case, use the gradation used in the series of values and use "about" for each value. You can determine the ranges available for a term. If present, all ranges are inclusive. are interoperable and combinable, i.e., references to ranges of values are within that range. Includes all values of

[0091] Unless otherwise specified, the term "aqueous" refers to a mixture of at least about 9 parts by weight of solvent. Refers to a solvent system containing 8% water by weight. In some applications, it may be soluble, miscible, or partially miscible. A compatible co-solvent (emulsified by surfactant or other means) may be present, which allows For example, the range of water mobilities is increased (e.g., alcohol / glycol). In this case, an additional independent embodiment is that the "aqueous" solvent system has at least about 5% by weight of the total solvent. 5% by weight, at least about 60% by weight, at least about 70% by weight, at least about 75% by weight , at least about 80% by weight, at least about 85% by weight, at least about 90% by weight, In some cases, the water content may be about 95% by weight, or at least about 98% by weight. In some circumstances, the aqueous solvent may consist essentially of water and be substantially free of co-solvents or other chemical species. The solvent system may be at least about 90% by weight, at least about 95% by weight, or at least about 98% by weight water, and in some embodiments, a co-solvent or It may not contain other chemical species.

[0092] Unless otherwise specified, the term "non-aqueous" refers to a mixture containing less than about 10% water by weight, generally An additional independent embodiment refers to a solvent system that includes at least one organic solvent in a "non-aqueous" solvent system. The solvent system is less than about 50% by weight, less than about 40% by weight, or less than about 30% by weight of the total solvent. , less than about 20% by weight, less than about 10% by weight, less than about 5% by weight, or less than about 2% by weight of water. The present invention includes embodiments including the following.

[0093] As used herein, the terms "aqueous electrolyte," "electrolyte solution," and the like These variations (commonly referred to as "electrolytes") are solvent systems containing at least one substance. and is intended to mean a solvent system having a higher conductivity than a solvent system without the substance.

[0094] The terms "electrochemically active electrolyte" or "redox active electrolyte" and their Variations of these terms convey their ordinary connotations to one skilled in the art of electrochemistry. are capable of redox transition, i.e., by capture or release of at least one electron. and electrolyte compositions (compounds) that can change oxidation state or valence state upon application of an electric potential. In the context of metal-ligand coordination compounds, the metal is and can be said to be redox active, or the ligand has an accessible valence state of capable of accepting / releasing electrons and are said to be redox active, or The redox active material may include one or both of a redox active metal and a ligand.

[0095] The electrolyte may contain a variety of redox active materials. Examples of electrolytes include, among others, amphoteric The active material of the positive electrode is a vanadium-based electrolyte containing vanadium ions. an iron-chromium based electrolyte containing iron ions as a negative electrode active material and chromium ions as a negative electrode active material; The positive electrode active material contains manganese ions, and the negative electrode active material contains titanium ions. Manganese-titanium based electrolyte, manganese containing manganese ions and titanium ions at both electrodes -Titanium-based electrolytes.

[0096] In some embodiments, the electrochemically active electrolyte comprises a metal-ligand coordination compound. In other embodiments, the electrochemically active electrolyte comprises redox active metal ions and / or The redox-inactive metal ions are preferably metal-ligand coordination compounds. Redox-active or redox-inactive metal ions are Al, Ca, Co, Cr, Sr, Cu, Fe, Mg, Mn, Mo, Ni, Pd, Pt, Ru, Sn, Ti, V, Zn, or In another embodiment, the electrochemically active electrolyte The material includes an organic active material. Preferably, the organic active material is carbon, an aromatic hydrocarbon, or any of these. Examples of aromatic compounds include, but are not limited to, quinones, Hydroquinone, viologen, pyridinium, pyridine, acridinium, or catechol In some preferred embodiments, the electrolyte is a vanadium-based electrolyte. include.

[0097] As used herein, the term "redox couple" is used by skilled electrochemists to is a commonly recognized term of art that refers to the oxidation of a chemical species in a predetermined redox reaction. Refers to the form (electron acceptor) and the reduced form (electron donor). Fe(CN)6 3- / Fe(CN) 6 4- This pair is just one non-limiting example of a redox couple. The term "metal ion" refers to a metal that undergoes a change in oxidation state under the conditions of use. As used herein, the term "redox couple" is intended to mean The term can refer to organic or inorganic pairs of materials.

[0098] In addition to the redox active material, the electrolyte contains solvents, buffers, supporting electrolytes, viscosity modifiers, wetting agents, The electrolyte, as defined herein, may also contain additional components such as: Impurities may include metallic elements, including heavy metals. Examples of solvents include H2SO4, K 2SO4, Na2SO4, H3PO4, H4P2O7, K2HPO4, Na3PO4, K At least one of 3PO4, HNO3, KNO3, HCl, NaNO3, NaOH, or KOH Alternatively, the solvent may be an organic acid solvent.

[0099] As used herein, the term "impurities" refers to the are not intended to participate in the functioning of the electrochemical cell as in the electrical Unwanted materials, typically containing metals or metalloids, that are detrimental to the safe and efficient use of the gas-chemical cell This implies its recognized meaning of referring to a chemical species that is typically present accidentally. and introduced as an impurity (in the traditional sense of the term) along with the intended substance. For example, As discussed elsewhere herein, some systems may contain incidental arsenic, The presence of thiamine and other such materials will form deposits during the operation of the flow battery. Although they are not believed to be of any benefit to the operation of low-energy batteries or fuel cells, their presence This may adversely affect performance. The distinction between defining impurities in terms of what is not considered or is not considered are also being considered or even selected for use as redox active materials in some applications. Metals or metalloids that may be present in other electrolytes may be considered impurities. For example, titanium-containing metal-ligand coordination compounds are used in selected redox-active In electrolyte compositions that are active electrolytes, the primary redox-active electrolyte in other systems is Despite the fact that vanadium is selected as the The presence of is likely to be seen as an impurity.

[0100] As used herein, the term "reduced form of an impurity" refers to a compound in the initial electrolyte solution. It refers to the form of an impurity that has a lower oxidation state than the impurity. For example, most metals or As used herein, metalloids are cationic species or have a formal positive charge. When present in solution as impurities, the metallic form (i.e., formal (having a zero valence state) or in hydride form, e.g., arsine, stibine, germane etc. have a formal negative valence state and are therefore considered to be reduced forms of the corresponding impurities. The pure reductant may include any reductant of the impurity. The reductant is volatile. In a further embodiment, the reductant of the impurity is a volatile hydride. Common reduced impurities include, but are not limited to, arsine (AsH3), geranium (Ge), GeH4, stannane (SnH4), stibine (SbH3), or combinations thereof In some embodiments, the reduced form of the impurity is AsH3. In an embodiment, the reduced form of the impurity is GeH4. In a further embodiment, the reduced form of the impurity is In yet another embodiment, the reduced form of the impurity is SbH. In its pure form, the reduced form of the impurity is elemental mercury.

[0101] As used herein, the term "inorganic material" refers to any material in the art of electrochemistry and inorganic chemistry. This may include "metal-ligand coordination compounds" or simply "coordination compounds" as known to those skilled in the art. A coordination compound may contain a metal ion bound to an atom or molecule. Or molecules are referred to as "ligands." In certain non-limiting embodiments, a ligand is a C atom. The ligand may comprise a molecule containing an organic atom, a H atom, a N atom, and / or an O atom. In some embodiments, the coordination compound may comprise a water, hydroxide, or halide molecule. Monomer ions (F - , Cl - , Br - , I - ), but contains at least one ligand that is not The invention is not limited to these embodiments. Additional embodiments include those described in U.S. Pat. No. 9,768, 463, which includes at least one of the coordination compounds The teachings of which are incorporated herein by reference.

[0102] As used herein, the terms "negative electrode" and "positive electrode" refer to the time course of a charging cycle. Regardless of the actual potential at which they operate during both the charge and discharge cycles, the negative electrode A device that is designed or intended to operate at a more negative potential than the electrode (and vice versa). The electrodes are defined relative to each other as shown. The negative electrode is negative relative to the reversible hydrogen electrode. whether or not they actually operate or are designed or intended to operate at There are also cases where this is not possible.

[0103] In this disclosure, the negative electrode associated with the first aqueous electrolyte of the balancing cell is the negative electrode of the working flow battery. They may comprise the same material as the electrodes or different materials, but they share a common electrolyte. In contrast, the positive electrode associated with the second aqueous electrolyte in the equilibration cell almost always has a working flow current. The positive electrode of the flow battery contains a different material than the positive electrode of the flow battery. In this case, the positive electrolyte of the flow battery almost always It is compositionally different from and physically isolated from the second electrolyte in the cell.

[0104] The terms "negolite" and "posolite" generally refer to the negative and positive electrodes, respectively. However, as used herein, "Negolite" and related electrolytes The terms "polysolite" and "polysolite" are limited to the respective electrolytes of flow batteries. As mentioned above, the negative working electrolyte (negolite) of the flow battery is a coordination compound or metal-ligand Includes coordination compounds. In certain embodiments, negolite has the following formula: M(L 1 ) x (L 2 ) y (L 3 ) z m The present invention includes a metal-ligand coordination complex having the formula: In the formula, M represents Al, Ca, Ce, Co, Cr, Fe, Mg, Mn, Mo, or Si. , Sn, Ti, V, W, Zn, or Zr, and L 1 , L 2 , and L 3 are independent of each other Ascorbate, catecholate, citrate, glycolate, or polyol (e.g., (including ligands derived from ethylene glycol, propylene glycol, or glycerol) , gluconates, glycinates, α-hydroxyalkanoates (e.g., α-hydroxy (derived from hydroxyacetate or glycolic acid), β-hydroxyalkanoate, γ-hydroxy Sialkonoate, maleate, phthalate, pyrogallate, sarcosinate , salicylate, or lactate; and x, y, and z are independently 0, 1, 2, or 3, 1≦x+y+z≦3, and m is +1, 0, -1, -2, -3, -4 , or -5.

[0105] Related independent embodiments are: (a) x=3, y=z=0; (b) x=2, y=1, z= 0, (c)x=1,y=1,z=1,(d)x=2,y=1,z=0,(e)x=2,y =z=0, or (f) x=1, y=z=0. In a more preferred embodiment, M is Al, Cr, Fe, or Ti, and x+y+z=3. In a preferred embodiment, the negolite comprises a metal-ligand coordination compound of titanium. In embodiments, negolite comprises a metal-ligand coordination compound of vanadium.

[0106] In other embodiments, the redox active material has the following formula: M n Ti(L1)(L2)(L3) This invention relates to a compound having the formula: wherein L1 is a catecholate, and L2 and L3 are each independently a catecholate. Cholate, ascorbate, citrate, glycolate, polyols, gluconate, gluconate Lysinate, hydroxyalkanoate, acetate, formate, benzoate, maleate esters, maleates, phthalates, sarcosinates, salicylates, oxalates, and ureas , polyamine, aminophenolate, acetylacetone, or lactate; Each M is independently Na, Li, or K, and n is 0 or an integer from 1 to 6, with the proviso that When both L1 and L2 are catecholates, L3 is oxalate, urea, catecholate, or Not cholate or acetylacetone.

[0107] In some embodiments, the catecholate is 1,2-dihydroxybenzene, 1,2,3 -trihydroxybenzene, 1,2,4-trihydroxybenzene, or mixtures thereof A preferred embodiment includes the following formula: M n Ti(catecholate)2(hydroxycatecholate), or M n Ti (catecholate To)3 The composition includes a composition having:

[0108] In other embodiments, the redox active composition has the following formula: M n Ti(L1)(L2)(L3) The composition is or comprises one or more compositions having wherein L1 is a catecholate, and L2 and L3 are each independently a catecholate. Cholate, ascorbate, citrate, glycolate, polyols, gluconate, gluconate Lysinate, hydroxyalkanoate, acetate, formate, benzoate, maleate esters, maleates, phthalates, sarcosinates, salicylates, oxalates, and ureas , polyamine, aminophenolate, acetylacetone, or lactate; Each M is independently Na, Li, or K, and n is 0 or an integer from 1 to 6. L1, L2, or L3 may also be represented by the following chemical formula I: [ka] or an oxidized or reduced form thereof. wherein Ar is a 5-membered alkyl group optionally containing one or more O, N, or S ring heteroatoms. a 20-membered aromatic moiety, and X1 and X2 are independently -OH, -NHR2, -SH, or are their anions, X1 and X2 are arranged ortho to each other, and R1 is , H, C, independently 1~6 Alkoxy, C 1~6 Alkyl, C 1~6 Alkenyl , C 1~6 Alkynyl, 5- or 6-membered aryl or heteroaryl, boronic acid or or its salt, carboxylic acid or its salt, carboxylate, cyano, halogen, hydroxy oxyl, nitro, sulfonate, sulfonic acid or their salts, phosphonate, phosphatase carboxylic acids or salts thereof, or polyglycols (preferably polyethylene glycols) ) and R2 is independently H or C 1~3 alkyl, and n is 0, 1, or 2 , 3, 4, 5, 6, 7, 8, 9, or 10.

[0109] Other suitable active materials may include "organic active materials." Organic active materials include transition metal ions. Furthermore, the organic active material may comprise molecules or supramolecules that are dissolved in aqueous solution. It is understood that the term "organic active material" is understood to include supramolecules. Suitable organic active materials are suitable for electrochemical energy storage. During the operation of the storage system, the oxidation state can be changed. The molecules can accept or donate electrons during the operation of the system.

[0110] "Catecholate", "glycolate", "polyol", "hydroxyalkanoate" The terms "," "benzoate," "phthalate," "urea," and "polyamine" , these ligands are H, C 1~6 Alkoxy, C 1~6 Alkyl, C 1~6 Alkenyl , C 1~6 Alkynyl, 5- or 6-membered aryl or heteroaryl, boronic acid or or its salt, C 0~6 Alkylene-carboxylic acid or its salt, cyano, halogen, hydride Hydroxyl, nitro, sulfonate, sulfonic acid or their salts, phosphonate, phosphatase sulfonic acid or a salt thereof, or polyglycol (preferably polyethylene glycol) and optionally substituted with at least one group independently selected from .

[0111] Alkanoates include α-, β-, and γ-types. Polyamines are limited to: Although not a com- pound, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), and diethyl These include diamines and triamines such as diaminetriaminepentaacetic acid (DTPA). The term "compound" includes all compositions containing 1,2-dihydroxybenzene moieties. These include not only hydroxycatecholates (including pyrogallate), but also those listed herein. The substituents include, but are not limited to, alkyl, alkenyl, and the like. and alkynyl (each having a branched or linear structure and one or more carboxyl groups) , halogen groups, hydroxyl groups, or other electron-withdrawing or electron-donating groups. The substituents include 5- or 6-membered aryl or heteroaryl groups. Also includes phenyl, pyridinyl, furyl, pyrrolyl, imidazolyl, triazole , or thiophenyl. Electron-withdrawing or electron-donating substituents are attached to the periphery of the aromatic ring. By attaching to the rim, the redox potential of the redox active ligand can be adjusted.

[0112] The terms "parts per million (ppm)" and "parts per billion (ppb)" are used to refer to the amount of The mass of the electrolyte solution is determined by mass relative to the total mass of the electrolyte solution. Thus, the terms "mg / mol" and "μg / mol" refer to the same redox-active electrolytic This refers to the concentration of impurities relative to the amount of redox-active electrolyte in the solid solution.

[0113] The term "stack" or "cell stack" or "electrochemical cell stack" refers to an electrochemical cell stack. Refers to a collection of individual electrochemical cells electrically connected together. The cells may be electrically connected in series or parallel. The cells may or may not be fluidly connected.

[0114] [Embodiment] Embodiment 1. A method for preparing an electrolyte solution having reduced impurity levels, comprising: a. Electrochemically treated electrolyte containing reduced forms of redox-active electrolytes and reduced forms of impurities under conditions sufficient to produce a redox solution of at least 0.5M concentration. The impurities present at an initial concentration in the initial electrolyte solution further containing a catalytically active electrolyte are electrochemically reduced. To restore and b. separating the reduced forms of the impurities from the electrochemically treated electrolyte solution; Obtaining a final electrolyte solution containing impurities having a final concentration lower than the initial concentration of the impurities And, A method comprising:

[0115] Aspect 2. The final concentration of the impurity in the final electrolyte solution is below a predetermined threshold level. and (i) Less than about 10 mg / L, less than 5 mg / L, less than 2.5 mg / L, less than 1 mg / L, 5 Less than 00μg / L, Less than 250μg / L, Less than 100μg / L, Less than 50μg / L, Approximately 4 Less than 0 μg / L, less than about 30 μg / L, less than about 20 μg / L, less than about 10 μg / L, less than about 5 one or more predetermined impurities at less than, or about, 1 μg / L; or (ii) about 1 mole of the redox active electrolyte in the redox active electrolyte solution Impurities less than 10 mg ([mg / mol]), less than 5 mg / mol, 2.5 mg / mol Less than, Less than 1mg / mol, Less than 500μg / mol, Less than 250μg / mol, 100 Less than μg / mol, less than 50 μg / mol, less than about 40 μg / mol, about 30 μg / mol less than 1 μg / mol, less than about 20 μg / mol, less than about 10 μg / mol, less than about 5 μg / mol, or less than about 1 μg / mol of one or more predetermined impurities; 2. The method of embodiment 1, wherein

[0116] Aspect 3. The impurity is antimony, arsenic, germanium, tin, or a combination thereof. 3. The method of claim 1 or 2, including combining the

[0117] Aspect 4. Any one of Aspects 1 to 3, wherein the electrochemical treatment is carried out in an electrochemical cell. Two ways.

[0118] Aspect 5. The reduced form of the impurity is separated by plating in the positive electrode of the electrochemical cell. The method of aspect 4,

[0119] Aspect 6. The reduced form of the impurity is precipitated from the electrochemically treated electrolyte solution. 2. The method of any one of aspects 1 to 5.

[0120] Embodiment 7. The method of embodiment 6, wherein the reduced form of the precipitated impurity is removed by filtration.

[0121] Aspect 8. The method of any one of Aspects 1 to 4, wherein the reduced form of the impurity is a volatile hydride. Law.

[0122] Aspect 9. The volatile hydride is arsine (AsH), germane (GeH), stannous hydride (STA), or argon hydride (AR). 9. The compound of claim 8, wherein the compound is benzophenone (SnH), stibine (SbH), or a combination thereof. method.

[0123] Aspect 10. The electrochemical treatment is electrochemical reduction, and the reduction potential of the impurity is lower than the reduction potential of the impurity. The method of any one of embodiments 1 to 9, wherein the method is carried out at a negative redox potential.

[0124] Aspect 11. The electrochemically treated electrolyte solution, (a) heating the electrochemically treated electrolyte solution at a temperature in the range of 20°C to about 105°C; Heating, (b) the electrochemically treated electrolyte solution or the electrolyte solution heated in step (a) Purging the liquid with an inert gas, or (c) a combination of steps (a) and (b); 11. The method of any one of aspects 1-10, further comprising conditioning by

[0125] Aspect 12. The temperature in the heating step (a) is about 35°C to about 95°C, or more preferably The method of embodiment 11, wherein the temperature is within the range of about 45°C to about 85°C.

[0126] Aspect 13. The method of Aspect 11 or 12, wherein the inert gas is nitrogen or argon.

[0127] Aspect 14: Any of Aspects 11 to 13, wherein steps (a) and (b) are carried out simultaneously. One way.

[0128] Aspect 15. Any of Aspects 11 to 13, wherein steps (a) and (b) are performed sequentially. One way.

[0129] Aspect 16. Oxidizing the reduced form of the redox active electrolyte in the final electrolyte solution. 16. The method of any one of aspects 1 to 15, further comprising:

[0130] Aspect 17. The oxidation is performed by perfusing the final electrolyte solution with an oxidizing agent such as oxygen, preferably air. 17. The method of embodiment 16, carried out by:

[0131] Aspect 18. The method of any one of Aspects 1 to 15, wherein the oxidation is carried out using hydrogen peroxide. method.

[0132] Aspect 19. The oxidation is carried out while heating the final electrolyte solution. Any one of the 8 methods.

[0133] Aspect 20. The oxidation is preferably carried out at a temperature of about 65°C or higher, more preferably at a temperature of about 85°C or higher. 20. The method of embodiment 16 or 19, more preferably carried out at a temperature of about 105° C. or greater.

[0134] Embodiment 21 The method of embodiment 16, wherein said oxidation is carried out using a hydrogen generating catalyst.

[0135] Aspect 22. The hydrogen generation catalyst is activated carbon, carbon cloth, carbon felt, carbon Ti mesh, Ti felt, expanded Ti mesh, Pt plated 22. The method of embodiment 21, wherein the surface roughness is 100% or less than 100% by weight, ...

[0136] Aspect 23. The redox active electrolyte is (i)Al, Ca, Co, Cr, Sr, Cu, Fe, Mg, Mn, Mo, Ni, Pd, P metal-ligand coordination compounds containing t, Ru, Sn, Ti, V, Zn, or Zr; (ii) organic active materials, preferably carbon, aromatic hydrocarbons, e.g., quinone, hydroquinone; , viologen, pyridinium, pyridine, acridinium, or catechol, or (iii) a combination of (i) or (ii); 23. The method of any one of aspects 1 to 22, comprising:

[0137] Aspect 24. The redox-active electrolyte is Co, Cr, Cu, Fe, Mn, Mo, Ru 24. The method of embodiment 23, comprising a metal-ligand coordination compound comprising the pair of Sn, Ti, V, or Zr.

[0138] Aspect 25. An electrolyte solution prepared by the method of any one of Aspects 1 to 24.

[0139] Embodiment 26. An electrolyte solution comprising: (i) a metal-ligand coordination compound, preferably containing a metal or metalloid, more preferably titanium; a redox-active electrolyte at a concentration of at least 0.5 M, including (ii) less than about 500 μg per liter of said electrolyte solution, or impurities present in amounts less than 500 μg per mole of electrolyte; an electrolyte solution comprising:

[0140] Embodiment 27. The embodiment comprising less than about 50 μg / L of one or more of As, Ge, Hg, and Sb. 25 or 26 electrolyte solutions.

[0141] Embodiment 28. Less than about 20 μg / L, less than about 15 μg / L, less than about 10 μg / L, or less than about 5 μg / L Less than μg / L of antimony, arsenic, germanium, tin, or any combination thereof 28. The electrolyte solution of any one of aspects 25 to 27, including one form.

[0142] Aspect 29. Less than about 5 μg / L of antimony, arsenic, germanium, tin, or any of their 29. The electrolyte solution of any one of embodiments 25-28, including one or more combinations thereof.

[0143] Embodiment 30. An electrochemical cell comprising the electrolyte solution of any one of embodiments 25-29.

[0144] Embodiment 31. A redox flow battery comprising at least one electrochemical cell of embodiment 30.

[0145] Embodiment 32. First Half-Cell Chamber and Second Half-Cell Separated by a Cation Exchange Membrane 1. An electrochemical cell comprising a chamber, The first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity. a first electrode, preferably a carbon electrode, in contact with an aqueous electrolyte; and The second half-cell chamber contains a second electrode in contact with a second aqueous electrolyte, wherein the second aqueous electrolyte contains aprotic cations at a concentration of at least 0.1M. and the second electrode is preferably nickel, such as Ni foam, or stearyl. Stainless steel mesh, stainless steel felt, Ni oxide, Ni hydroxide, Ni oxyhydroxide An electrochemical cell comprising an O2-generating catalyst comprising an oxide or Ni-Fe oxide.

[0146] Embodiment 33. First Half-Cell Chamber and Second Half-Cell Separated by a Cation Exchange Membrane 1. An electrochemical cell comprising a chamber, The first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity. A first electrode, preferably a carbon electrode, e.g., carbon cloth, carbon, in contact with the aqueous electrolyte. -Bonnfeld, or carbon paper, and The second half-cell chamber has a pH of at least 2 and a concentration of at least 0.1 M. a first aqueous electrolyte in contact with a second aqueous electrolyte comprising one or more salts having an aprotic cation of Two electrodes are provided, The second electrode contains a catalyst, preferably platinum, cobalt, or iridium, that generates O2. , iron, manganese, nickel, ruthenium, tin, or a combination thereof An electrochemical cell comprising at least one, most preferably IrO2.

[0147] Aspect 34. The reducible impurities are converted to volatile reductants, e.g., aluminum, upon electrochemical reduction. AsH3, germane (GeH4), stannane (SnH4), or stibine (Sb 34. The electrochemical cell of embodiment 32 or 33, forming H3).

[0148] Embodiment 35. The second aqueous electrolyte is Na + ions and / or K + Contains ions and has few The electrochemical cell of any one of embodiments 32 to 34, having a pH of at least 7.

[0149] Aspect 36. A method of operating the electrochemical cell of any one of Aspects 32-35, comprising: the concentration of the reducible impurities in the first aqueous electrolyte is adjusted to a predetermined concentration in the first aqueous electrolyte. the electrochemical cell under conditions sufficient to reduce the level, preferably to less than 10 μg / L passing a sufficient current through the [Example]

[0150] The following examples are presented to illustrate some of the concepts described within this disclosure. The examples are to be construed as illustrating specific individual embodiments of compositions, methods of preparation, and methods of use. Any examples are to be considered limitations of the more general embodiments described herein. It shouldn't be.

[0151] [Example 1] As noted above, in certain embodiments, the electrochemical cell comprises a first electrode separated by a membrane. and a second half-cell chamber, wherein the first half-cell chamber comprises: A first aqueous solution containing a redox active electrolyte (e.g., negolite) and reducible impurities A first electrode, preferably a carbon electrode, e.g., carbon cloth, carbon, in contact with the electrolyte. The second half-cell chamber preferably contains an acid a second electrode in contact with a second aqueous solution that is neutral but has a pH of at least 2; Here, the second electrode is made of a catalyst that generates O2, preferably platinum, cobalt, or iridium. oxides of tungsten, iron, manganese, nickel, ruthenium, tin or combinations thereof The material contains at least one of the following, most preferably IrO2.

[0152] To demonstrate an exemplary embodiment in this context, a cation exchange membrane with a carbon electrode The negative electrode is made of an iridium oxide catalyst coated on top of a non-conductive layer. An experiment was carried out using carbon cloth isolated from the membrane as the positive electrode (see Figure 3(A)). The non-conductive layer may be an electrically insulating but fluid-permeable material such as a grid or foam. It has been found that melamine foam is useful for this non-conductive layer. It is known that the non-conductive layer is formed by decomposition of negolite as described elsewhere herein. This configuration separates the reduction of negolite from the acid flow from the negative electrode, which can cause The electrochemical cell is then charged with a titanium ligand coordination compound (e.g., a titanium-catecholate complex). The redox-active electrolyte (Negolite) solution containing 1000 ppm of ethylenediaminetetraacetic acid was used as a flow cell through the positive electrode. Water for the negative electrode was supplied by diffusion from the negolite solution. In practice, this design Up until now, redox currents have been measured at current densities of approximately 30 or 40 mA per square centimeter. The battery was limited to charging with an active electrolyte solution to the positive electrode, which would cause the decomposition of the titanium complex. The current density was thought to be limited by the transport of acid from the ion exchange membrane. However, such compositions contain titanium-catecholate complexes at concentrations greater than 0.7M, e.g. The final redox active electrolyte solution contains arsenic at levels less than 10 μg / L as a typical impurity. This has been demonstrated to provide proof of concept for the principles described herein for providing a liquid.

[0153] [Example 2] As noted above, in certain embodiments, the electrochemical cell comprises a first electrode separated by a membrane. and a second half-cell chamber, wherein the first half-cell chamber comprises: a first aqueous electrolyte containing a redox active material and a reducible impurity; the second half-cell chamber contains a second aqueous alkaline a second electrode in contact with the anode (anolyte) solution, wherein the second electrode is preferably Nickel such as Ni foam, stainless steel mesh, stainless steel felt, Ni oxide Ni-Fe oxide, Ni hydroxide, Ni oxyhydroxide, or Ni-Fe oxide Contains a catalyst.

[0154] In an exemplary embodiment in this context, the anode solution contains sodium hydroxide, potassium hydroxide, The negative electrodes were concentrated solutions of ammonium chloride, phosphate buffer, or a mixture thereof (see Figure 3(B)). The electrodes consist of a conventional alkaline oxidation catalyst, in these cases nickel or nickel-coated steel. The positive electrode was a carbon electrode. A cation exchange membrane, e.g., NAFION® Perfluorosulfonic acid resin or sulfonated polyetheretherketone (s-PEEK) The positive and negative electrodes were separated by a titanium-ligand coordination compound (e.g., A redox-active electrolyte (negolite) solution containing a titanium-catecholate complex and a negative electrode The design was a flow cell in which both polar solutions were pumped across the cell. Acceptable results were achieved as described in Example 1.

[0155] [Example 3] 25cm 2 The HERM device was mounted on a Ni foam anode (346 g / m 2 , 1.6mm thick , Porosity: ≧95%, 80ppi~110ppi, MTI Inc.), Nafion N11 The battery was constructed using a 7-member cation exchange membrane and a carbon cloth cathode. The anode solution was 1M K. OH was used. Using this device, 3.1 ppm of As was measured by ICP-OES. and Ti-catecholate negolyte having a concentration of 1.2M containing 2.9 ppm Sn. The charge of Negolite was 180mA / cm 2 and Ag / AgCl The solution potential was -1.36 V. The solution was sparged with nitrogen and magnetically heated at 45 °C for 16 h. After stirring, the electrolyte was refluxed and sparged with nitrogen for an additional 20 hours to obtain a At the end of these conditioning steps, the ICP-OE S showed less than 1.0 ppb of As and 1.6 ppm of Sn. It shows that the impurity concentrations were reduced by >99% and 45%, respectively.

[0156] [Example 4] 25cm 2 The HERM device was constructed with a Nafion N117 membrane coated with IrO2. The membrane was constructed with a carbon cloth anode facing the cathode. A non-conductive layer of melamine foam was placed between the electrodes. Ti-catecholate negolite with a concentration of 1.2 M containing s was purified. The charge of the light is 40mA / cm 2 The reaction proceeds at a solution potential of -1.34 V vs. Ag / AgCl. The temperature was increased by sparging with nitrogen and stirring magnetically at 65°C for 2.5 hours. After this conditioning step, the electrolyte contained 6 It was found to contain 0.7 ppb of As, a reduction in As concentration of over 99%.

[0157] [Example 5] Ti-catecholate nephrine with a concentration of 1.2M contaminated with more than 20 mg / L of Zn Gorite was purified. This electrolyte was charged to -1.42 V vs. Ag / AgCl. Zn plating occurred extensively on the carbon cathode of the HERM device (Figure 4 shows the Zn plating on the HERM cathode). (showing plated Zn).

[0158] Those skilled in the art will appreciate that many modifications and variations of the present invention are possible in light of these teachings. and all such are contemplated herein.

[0159] The disclosure of each patent, patent application, and publication cited or described herein is hereby incorporated by reference. and each is hereby incorporated by reference in its entirety for all purposes. do.

Claims

1. 1. A method for preparing an electrolyte solution having reduced impurity levels, comprising: a. An electrochemically treated electrolyte containing a reduced form of a redox-active electrolyte and a reduced form of an impurity. and a redox concentration of at least 0.5 M under conditions sufficient to produce a saturated electrolyte solution. The impurities present at an initial concentration in the initial electrolyte solution further containing a catalytically active electrolyte are electrochemically reduced. To restore and b. separating the reduced forms of the impurities from the electrochemically treated electrolyte solution; Obtaining a final electrolyte solution containing impurities having a final concentration lower than the initial concentration of the impurities And, A method comprising:

2. the final concentration of the impurity in the final electrolyte solution is at a predetermined threshold level; (i) less than about 10 mg / L, less than 5 mg / L, less than 2.5 mg / L, less than 1 mg / L; Less than 500 μg / L, less than 250 μg / L, less than 100 μg / L, less than 50 μg / L, about Less than 40 μg / L, less than about 30 μg / L, less than about 20 μg / L, less than about 10 μg / L, one or more predetermined impurities at less than 5 μg / L, or less than about 1 μg / L; or (ii) about per mol of the redox active electrolyte in the redox active electrolyte solution Impurities less than 10 mg ([mg / mol]), less than 5 mg / mol, 2.5 mg / mol less than 1 mg / mol, less than 500 μg / mol, less than 250 μg / mol, 100 Less than μg / mol, less than 50 μg / mol, less than about 40 μg / mol, about 30 μg / mol less than about 1 μg / mol, less than about 20 μg / mol, less than about 10 μg / mol, less than about 5 μg / mol, or less than about 1 μg / mol of one or more predetermined impurities; The method of claim 1, wherein

3. The impurities may be in the form of antimony, arsenic, germanium, tin, or combinations thereof. The method of claim 1 , comprising:

4. The method of claim 1 , wherein the electrochemical treatment is carried out in an electrochemical cell.

5. The reduced forms of the impurities are separated by plating in the positive electrode of the electrochemical cell. The method according to claim 4.

6. The reduced form of the impurity is precipitated from the electrochemically treated electrolyte solution.

1. The method according to claim 1.

7. 7. The method of claim 6, wherein the reduced forms of the precipitated impurities are removed by filtration.

8. 10. The method of claim 1, wherein the reduced form of the impurity is a volatile hydride.

9. The volatile hydrides include arsine (AsH), germane (GeH ４ ), Stannan ( SnH ４ ), stibine (S ｂ H ３ ), or a combination thereof. method.

10. The electrochemical treatment is electrochemical reduction, and the oxidation potential is more negative than the reduction potential of the impurities.

10. The method of claim 1 carried out at a reducing potential.

11. (a) subjecting the electrochemically treated electrolyte solution to a temperature in the range of 20°C to about 105°C. Heating, (b) the electrochemically treated electrolyte solution or the electrolyte heated in step (a) Purging the solution with an inert gas, or (c) a combination of steps (a) and (b); and further conditioning the electrochemically treated electrolyte solution by The method of claim 1 , comprising:

12. The temperature of the heating step (a) is from about 35°C to about 95°C, or more preferably from about 45°C to 12. The method of claim 11, wherein the temperature is in the range of about 85°C.

13. The method of claim 11 , wherein the inert gas is nitrogen or argon.

14. 12. The method of claim 11, wherein steps (a) and (b) are performed simultaneously.

15. The method of claim 11 , wherein steps (a) and (b) are performed sequentially.

16. further comprising oxidizing the reduced form of the redox active electrolyte in the final electrolyte solution. The method of claim 1 .

17. The oxidation may be achieved by purging the final electrolyte solution with an oxidizing agent such as oxygen, preferably air.

17. The method of claim 16, wherein the method is performed by:

18. 17. The method of claim 16, wherein the oxidation is carried out using hydrogen peroxide.

19. 17. The method of claim 16, wherein the oxidation is carried out while heating the final electrolyte solution. 。

20. The oxidation is carried out at a temperature of about 65° C. or higher, preferably at a temperature of about 85° C. or higher, more preferably at a temperature of about 85° C. or higher.

17. The method of claim 16, wherein step a is carried out at a temperature of about 105°C or greater.

21. 17. The method of claim 16, wherein the oxidation is carried out using a hydrogen generation catalyst.

22. The hydrogen generating catalyst may be activated carbon, carbon cloth, carbon felt, or carbon paper. , Ti mesh, Ti felt, expanded Ti mesh, Pt-plated Ti mesh 22. The method of claim 21 , wherein the hydroxybenzoate is hydroxybenzoate, ...

23. The redox active electrolyte is (i) Al, Ca, Co, Cr, Sr, Cu, Fe, Mg, Mn, Mo, Ni, Pd, metal-ligand coordination compounds containing Pt, Ru, Sn, Ti, V, Zn, or Zr; (ii) Organic active materials, preferably carbon, aromatic hydrocarbons, e.g., quinone, hydroquinone , viologen, pyridinium, pyridine, acridinium, or catechol, or (iii) a combination of (i) or (ii); The method of claim 1 , comprising:

24. The redox active electrolyte may be Co, Cr, Cu, Fe, Mn, Mo, Ru, Sn, T 24. The method of claim 23, comprising a metal-ligand coordination compound comprising the set i, V, or Zr.

25. An electrolyte solution prepared by the method of any one of claims 1 to 24.

26. An electrolyte solution comprising: (i) a metal-ligand coordination compound, preferably containing a metal or metalloid, more preferably titanium; a redox-active electrolyte at a concentration of at least 0.5 M, including (ii) less than about 500 μg per liter of said electrolyte solution, or impurities present in an amount of less than 500 μg per mole of substrate; an electrolyte solution comprising:

27. 26. The method of claim 25, comprising less than about 50 μg / L of one or more of As, Ge, Hg, and Sb. Electrolyte solution.

28. Less than about 20 μg / L, less than about 15 μg / L, less than about 10 μg / L, or less than about 5 μg / L Any one form of antimony, arsenic, germanium, tin, or combinations thereof 26. The electrolyte solution of claim 25, comprising:

29. Less than about 5 μg / L of antimony, arsenic, germanium, tin, or a combination thereof 26. The electrolyte solution of claim 25, comprising one or more of:

30. 26. An electrochemical cell comprising the electrolyte solution of claim 25.

31. 31. A redox flow battery comprising at least one electrochemical cell according to claim 30.

32. a first half-cell chamber and a second half-cell chamber separated by a cation exchange membrane; An electrochemical cell comprising: The first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity. a first electrode, preferably a carbon electrode, in contact with an aqueous electrolyte; and the second half-cell chamber comprising a second electrode in contact with a second aqueous electrolyte; The second aqueous electrolyte contains aprotic cations at a concentration of at least 0.1 M. The second electrode preferably comprises nickel, stainless steel, or the like, such as Ni foam. Stainless steel mesh, stainless steel felt, Ni oxide, Ni hydroxide, Ni oxyhydroxide , or O containing Ni—Fe oxide ２ an electrochemical cell comprising a catalyst for generating

33. a first half-cell chamber and a second half-cell chamber separated by a cation exchange membrane; An electrochemical cell comprising: The first half-cell chamber contains a first half-cell containing a redox active material and a reducible impurity. A first electrode, preferably a carbon electrode, e.g., carbon cloth, carbon black, in contact with the aqueous electrolyte. -Bonnfeld, or carbon paper, and The second half-cell chamber has a pH of at least 2 and a concentration of at least 0.1 M. a first aqueous electrolyte in contact with a second aqueous electrolyte comprising one or more salts having an aprotic cation of two electrodes, The second electrode is O ２ a catalyst for generating the compound, preferably platinum, cobalt, or iridium , iron, manganese, nickel, ruthenium, tin, or a combination thereof At least one, most preferably IrO ２ an electrochemical cell comprising:

34. The reducible impurities are converted to volatile reductants, such as arsine (AsH), upon electrochemical reduction. 3), Germanium (GeH ４ ), Stannane (SnH ４ ), or stibine (SbH ３ ) form 33. The electrochemical cell of claim 32 comprising:

35. The second aqueous electrolyte is Na ＋ ions and / or K ＋ ions, and at least 7 33. The electrochemical cell of claim 32 having a pH.

36. 33. The method of operating an electrochemical cell of claim 32, comprising: The concentration of reducible impurities is adjusted to a predetermined level in the first aqueous electrolyte, preferably 1. passing a sufficient current through the electrochemical cell under conditions sufficient to reduce the concentration of EDTA to less than 0 μg / L; and

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