Electrochemical cell deionization system

Abstract

The invention relates to an electrochemical cell deionization system. A hydrogen electrochemical system comprising a cell comprising a membrane electrolyte and a catalyst layer loaded with a catalyst, and a deionizing subsystem comprising a selective binding chelating agent that binds one or more metal ions, and a deionizing subsystem located in a water recirculation loop of the battery, the deionizing subsystem comprising a selectively binding chelate having its hydrogen dissociated pKa value (s) that is different from the pH value (s) of the battery in operation, the selectively binding chelate having its hydrogen dissociated pKa value (s) that is different from the pH value (s) of the battery in operation.

Description

Technical Field

[0001] The present disclosure relates to deionization components, systems, subsystems and methods in electrochemical cells, particularly electrolyzers and fuel cells. Background Art

[0002] Hydrogen energy technologies such as fuel cells and electrolyzers are becoming increasingly popular due to their ability to produce and store clean energy. However, many challenges remain and hinder their large-scale production. In addition to the challenges of material selection caused by the harsh environment of fuel cells and electrolyzers, the degradation of components (such as catalysts and membranes) also needs to be addressed because degradation affects the efficiency of hydrogen energy devices. Summary of the invention

[0003] In one embodiment, a hydrogen electrochemical system is disclosed. The system may include a battery and a deionization subsystem, the battery including a membrane electrolyte and a catalyst layer loaded with a catalyst. The deionization subsystem may include a selective binding chelator that binds one or more metal ions, the selective binding chelator having a pKa value of its (one or more) hydrogen dissociation, and the (one or more) pKa value is different from the (one or more) pH value of the battery in operation. The deionization subsystem may be located in the water recycling loop of the battery. The (one or more) pKa value may differ from the (one or more) pH value by at least 10%. The battery may be an electrolyzer. The selective binding chelator may include an iron ion receptor. The selective binding chelator may include one or more carboxylic acid (-COOH) groups or derivatives thereof. The selective binding chelator may include one or more thujaplicins. The hydrogen electrochemical system may further include a regeneration device, the regeneration device being configured to strip the one or more metal ions after binding from the selective binding chelator. The pH value of the system may be 0-4, and the (one or more) pKa value may be lower and / or higher than 0-4. The deionization subsystem may be located in at least one catalyst layer of the cell.

[0004] In another embodiment, an electrolyzer system is disclosed. The electrolyzer system may include a water input source supplying a water input stream, an electrolyzer cell including a membrane electrolyte and a catalyst layer loaded with a catalyst located downstream of the water input source, and a deionization subsystem. The deionization system may be located upstream of the electrolyzer cell and downstream of the water input source. The device may include a chelating agent that binds one or more non-hydrogen ions present in the water input stream. The pKa value of the chelating agent may be different from any pH value of the electrolyzer in operation. The chelating agent may be deprotonated within the operating range of the cell. The chelating agent may have an iron ion receptor. The chelating agent may include one or more carboxylic acid (-COOH) groups or derivatives thereof. The chelating agent may include one or more thujaphenols. The electrolyzer system may further include a regeneration device configured to strip the bound one or more non-hydrogen ions from the chelating agent. The pH value of the electrolyzer in operation may be about 2, and the pKa value may be higher or lower than 2.

[0005] In yet another embodiment, an electrolyzer deionization device is disclosed. The electrolyzer deionization device may include a reservoir with a chelating agent having one or more dissociation constant pKa values ​​that are above or below the pH of an operating electrolyzer cell such that the proton volume in the electrolyzer cell remains unreduced in the presence of the chelating agent. The chelating agent may be deprotonated within the operating range of the electrolyzer cell. The chelating agent may include one or more thujaphenols. The electrolyzer deionization device may be located upstream of the electrolyzer cell.

[0006] BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a perspective exploded view of a non-limiting example battery;

[0008] Figure 2 is a schematic diagram of an electrolyzer and its operating principle;

[0009] Figure 3 is a schematic diagram of a non-limiting example electrochemical system including unwanted ions in an input stream into a cell;

[0010] Figure 4 is a schematic diagram of a non-limiting example electrochemical system including unwanted ions and an additive configured to capture these ions;

[0011] Figure 5 is a non-limiting example of an electrochemical cell maintenance cycle that includes an additive configured to remove unwanted ions from an input stream;

[0012] Figure 6is another non-limiting example system for removing unwanted ions, comprising a reusable ionophore;

[0013] Figure 7 is a non-limiting example chemical structure of a chemical sensor disclosed herein;

[0014] Figure 8 A schematic diagram showing a non-limiting example sensing device assembly connected to a power source and a battery;

[0015] Fig. 9 is a non-limiting example system including additives and ionic cleaners for removing unwanted ions;

[0016] Fig.10 is an illustrative, non-limiting example of a maintenance cycle for a system having a fixed additive;

[0017] Fig.11 is a schematic diagram of unwanted ion capture and release according to one or more embodiments disclosed herein;

[0018] Fig.12 is an illustrative, non-limiting example of an additive acceptor in a battery catalyst layer; and

[0019] Fig.13 is a schematic diagram of a non-limiting example system including a cell stack and a common additive reservoir. DETAILED DESCRIPTION

[0020] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. These drawings are not necessarily to scale; certain features may be magnified or minimized to show the details of a particular component. Therefore, the specific structural and functional details disclosed herein should not be interpreted as restrictive, but merely as a representative basis for teaching those skilled in the art to use the embodiments in different ways. As will be understood by those of ordinary skill in the art, the various features illustrated and described with reference to any of the figures may be combined with the features illustrated in one or more other figures to produce an embodiment that is not explicitly illustrated or described. The combination of features shown provides representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of the present disclosure may be required for specific applications or implementations.

[0021] Except in the examples or otherwise explicitly stated, all numerical values ​​in this specification indicating the amount of material or reaction and / or use conditions should be understood as being modified by the word "about" when describing the broadest scope of the invention. It is usually preferred to practice within the specified numerical limits. In addition, unless explicitly stated to the contrary: percentages, "parts" and ratio values ​​are all by weight; describing a group or class of materials as suitable or preferred for a given purpose related to the present invention means that mixtures of any two or more members of the group or class are also suitable or preferred; descriptions of ingredients in chemical terms refer to ingredients when added to any combination specified in the description, and do not necessarily exclude chemical interactions between ingredients of the mixture after mixing.

[0022] The first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation herein and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurements of properties are determined by the same techniques as previously or later cited for the same property.

[0023] It must also be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to a singular component is intended to include plural components.

[0024] As used herein, the terms "substantially", "roughly" or "approximately" mean that the amount or value in question can be a specified specific value or some other value in the vicinity thereof. Typically, the term "approximately" indicating a specific value is intended to indicate a range within + / - 5% of that value. As an example, the phrase "about 100" indicates a range of 100+ / -5, i.e., a range from 95 to 105. Typically, when the term "approximately" is used, it can be expected that similar results or effects according to the present invention can be obtained within a range of + / - 5% of the value shown. The term "substantially" can modify the value or related features disclosed or claimed in the present disclosure. In this case, "substantially" can indicate that the value or related characteristics it modifies are within ± 0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% or 10% of the value or relative feature.

[0025] It should also be understood that integer ranges explicitly include all intermediate integers. For example, the integer range 1-10 explicitly includes 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. Similarly, the range 1 to 100 includes 1, 2, 3, 4 ... 97, 98, 99, 100. Similarly, when any range is required, the intermediate number that is the difference between the upper and lower limits divided by the increment of 10 can be taken as an alternative upper or lower limit. For example, if the range is 1.1 to 2.1, the following numbers 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 and 2.0 can be selected as the lower or upper limit.

[0026] In the examples described herein, the concentrations, temperatures, and reaction conditions (e.g., pressure, pH, flow rate, etc.) may be implemented with the values ​​provided in the examples rounded or truncated to plus or minus 50% of the values ​​indicated by two significant figures. In a refinement, the concentrations, temperatures, and reaction conditions (e.g., pressure, pH, flow rate, etc.) may be implemented with the values ​​provided in the examples rounded or truncated to plus or minus 30% of the values ​​indicated by two significant figures. In another refinement, the concentrations, temperatures, and reaction conditions (e.g., pressure, pH, flow rate, etc.) may be implemented with the values ​​provided in the examples rounded or truncated to plus or minus 10% of the values ​​indicated by two significant figures.

[0027] For all compounds indicated as empirical chemical formulas with multiple letter and number subscripts (e.g., CHO), the value of the subscript may be rounded or truncated to two significant figures, plus or minus 50% of the indicated value. For example, if indicated as CHO, then the formula C (0.8-1.2) H (1.6-2.4) O (0.8-1.2) In one refinement, the value of the subscript may be plus or minus 30% of the value indicated by rounding or truncation to two significant figures. In yet another refinement, the value of the subscript may be plus or minus 20% of the value indicated by rounding or truncation to two significant figures.

[0028] As used herein, the term "and / or" means that all or only one element of the group may be present. For example, "A and / or B" means "only A, or only B, or both A and B". In the case of "only A", the term also covers the possibility that B is not present, that is, "only A, but not B".

[0029] It should also be understood that the present invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may of course vary. Furthermore, the terminology used herein is only for the purpose of describing specific embodiments of the present invention and is not intended to be limiting in any way.

[0030] The term "comprising" is synonymous with "including," "having," "containing," or "characterized by." These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps.

[0031] The phrase "consisting of" excludes any element, step, or ingredient not specified in a claim. When the phrase appears in the body of a claim rather than immediately following the preamble, it limits only the elements set forth in that clause; other elements are not excluded from the claim as a whole.

[0032] The phrase "consisting essentially of" limits the scope of a claim to the specified materials or steps, plus those materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.

[0033] With respect to the terms "comprising," "consisting of," and "consisting essentially of," where one of these three terms is used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms.

[0034] The term "one or more" means "at least one," and the term "at least one" means "one or more." The terms "one or more" and "at least one" include "plurality" as a subset.

[0035] Description of a group or class of materials as suitable for a given purpose in connection with one or more embodiments means that mixtures of any two or more members of the group or class are suitable. Descriptions of ingredients in chemical terms refer to the ingredients when added to any combination specified in the specification, and do not necessarily exclude chemical interactions between the ingredients of the mixture once mixed. The first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation herein, and mutatis mutandis applies to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurements of properties are determined by the same techniques as previously or later cited for the same property.

[0036] Electrochemical cells such as fuel cells, which convert the chemical energy of a fuel (e.g., H2) and an oxidant into electrical energy via a pair of electrochemical half (redox) reactions, have become an increasingly popular technology. Fuel cells are now a promising alternative transportation technology that is able to operate without emitting toxins or greenhouse gases. Currently, one of the limitations to the widespread adoption of this clean and sustainable technology is related to the clean production of H2 fuel.

[0037] Fuel cells present an environmentally friendly alternative to internal combustion engines for use in various vehicles such as cars and buses. Fuel cells are generally characterized by relatively high efficiency and power density. A very attractive feature of fuel cell engines is the absence of carbon emissions, provided that the hydrogen fuel is obtained in an environmentally friendly manner. In addition to being a green engine, fuel cells can also be used in other applications such as stationary and portable power sources.

[0038] Fuel cell technology; however, there are many challenges associated with its maintenance, long-term sustainable performance, lifespan, and production costs. For example, fuel cells have a highly corrosive environment, requiring materials that can withstand challenging conditions. While the focus is on the overall performance of the fuel cell, incremental improvements are still needed in the individual components of the fuel cell.

[0039] A non-limiting example of a PEMFC is depicted in Figure 1 The core component of the PEMFC 10 that helps produce the electrochemical reactions required to separate electrons is the membrane electrode assembly (MEA) 12. The MEA 12 includes subcomponents such as electrodes (cathode, anode), catalysts, and polymer electrolyte membranes. In addition to the MEA 12, the PEMFC 10 typically includes other components such as current collectors 14, (one or more) gas diffusion layers 16, gaskets 18, and (one or more) bipolar plates 20.

[0040] In a fuel cell, an electrolyte moves charged ions between the cathode and anode; in a PEM, the electrolyte moves protons from the anode to the cathode, while in an anion exchange membrane (AEM), the electrolyte can move hydroxide ions from the cathode to the anode. Organic membranes are useful as electrolytes because they can move ions at low temperatures, are cheaper than inorganic electrolytes, and can be made into thin layers (1 μm-1 mm, typically about 5-50 μm).

[0041] Similarly, another type of electrochemical cell, the electrolyzer, also utilizes the movement of protons through a membrane and the flow of electrons through an external circuit, like a fuel cell. Thus, a proton exchange membrane (PEM) electrolyzer stack can utilize an MEA. However, the direction of the reaction and energy flow in an electrolyzer is opposite to that of a fuel cell. A fuel cell consumes hydrogen and oxygen to produce electricity and water, while an electrolyzer is an electrochemical device that is designed to convert electricity and water into hydrogen and oxygen.

[0042] The electrolysis principle used by the PEM electrolyzer and the related reactions are schematically depicted in Figure 2 The electrolyzer 30 includes a PEM 32, an anode 34, and a cathode 36. During the electrolysis process, water is decomposed into oxygen and hydrogen in the electrically driven evolution reaction at the anode and cathode. The reactant liquid water (H2O) penetrates through the anode 34 porous transport layer (PTL) to the anode catalyst layer, where an oxygen evolution reaction (OER) occurs. In the hydrogen evolution reaction (HER) process at the cathode 36 catalyst layer, protons (H + ) travels through the PEM 32, and the electrons (e-) are conducted through an external circuit. Anode OER requires a much higher overpotential than cathode HER. Due to the slow nature of its four-electron transfer, anode OER determines the efficiency of water splitting.

[0043] Different materials are used to produce the PEM electrolyzer 30. An example of an anode PTL layer material may be titanium (Ti), and a cathode PTL layer may be a carbon-based material, such as carbon paper, carbon wool, etc. The PEM 32, anode 34, and cathode 36 may be surrounded by flow field plates, bipolar plates, or separator plates, which may be made of, for example, Ti, or Ti metal plated with gold or platinum.

[0044] Catalysts are typically used on the anode 34 and cathode 36 to assist the half-reaction process. A typical catalyst material on the cathode 36 is platinum (Pt), while a typical catalyst used on the anode 34 is ruthenium (Ru), iridium (Ir), Ir-Ru, ruthenium oxide (RuO2), iridium oxide (IrO2) or iridium ruthenium oxide (Ir-Ru-O) because of the combination of relatively high activity and durability.

[0045] In general, an electrolyzer breaks water into electrons, smaller ions (protons in a PEM or hydroxide ions in an AEM), and molecules (oxygen and hydrogen), allowing the electrons to flow into an external circuit. A fuel cell produces water from hydrogen or oxygen, consuming electrons in the process. The membrane typically contains water, corresponding to the production (in a fuel cell) or consumption (in an electrolyzer) of water. Humidified membranes typically have better ion transport properties and higher durability than dry membranes. Comparative reactions of fuel cells and electrolyzers are shown in Table 1 below:

[0046] Table 1 – Reactions at the anode and cathode for fuel cells and electrolysers

[0047]

[0048] Fuel cells and electrolyzers can be used together to store energy via hydrogen. Electrolyzers can be used in applications including industrial, residential and military applications as well as technologies focused on energy storage, such as grid stabilization from dynamic power sources including wind turbines, solar cells or localized hydrogen production for industrial and other uses.

[0049] The efficiency of an electrochemical cell is closely related to the efficiency with which ions can pass through the electrolyte. If it is difficult for ions to move through the electrolyte, i.e., the ionic resistance is high, a higher electrochemical potential is required for a fixed current, resulting in lower efficiency. The ionic resistance of an electrolyte is roughly proportional to its thickness. Therefore, it is desirable that the electrolyte is as thin as possible. At the same time, the electrolyte needs to be chemically resistant to prevent or resist degradation of the deionization system of the fuel cell stack according to claim 17, and mechanically robust to prevent mechanical degradation during operation over the expected life of the cell.

[0050] Membrane degradation can be caused by a variety of factors. For example, one catalyst for membrane degradation is a metal ion that can diffuse into the electrolyzer cell. The metal ion can be surrounded by a solvation shell of water. The metal ions can originate from impurities in the input stream, dissolution of atoms in the steel components of the electrochemical device, degradation of the catalyst material, etc. For example, if the electrochemical device is an electrolysis stack, insufficient purification of the input water may result in some ions remaining when entering the electrolyzer cell, such as Figure 3 In the drawings disclosed herein, the term impurity is used to denote unwanted ions. Figure 3 An input stream is depicted from a water source 52, which may carry water and impurities in the form of ions. As the water stream flows through the clarifier 54, some ions may be present and become a potential source of membrane degradation.

[0051] Ions can diffuse into the membrane, which can lead to side reactions and chemical degradation. A non-limiting example of a side reaction is the oxidation of hydroxide (OH-) ions to hydroxyl (·OH) radicals, such as: Fe 3+ +OH - →Fe 2+ +·OH. The hydroxyl radical is known to be a key component in many forms of membrane degradation, as it is chemically reactive and will therefore attack bonds within the polymer, leading to degradation. Other ions present in the cell may participate in electrochemical side reactions, thereby reducing cell efficiency. Therefore, there is a need to prevent Fe ions and other harmful ions from diffusing into the membrane, and to capture and / or passivate them if they do so.

[0052] In one or more embodiments, a system is disclosed. The system may include one or more devices including electrochemical cells. The electrochemical cell may be a hydrogen cell. The electrochemical cell may be a fuel cell or an electrolyzer, hereinafter referred to as a cell. The cell may be a membrane cell. In a non-limiting example, the cell may be a polymer electrolyte membrane (PEM) electrolyzer or an anion exchange membrane (AEM) electrolyzer. The system may further include components for removing ions or deionizing from the system. Removal may be a water recirculation loop from the cell, which includes but is not limited to an input stream, an output stream, (one or more) catalyst layers, or a combination thereof.

[0053] The component may include or be part of a "recovery protocol" for a battery, device, or system. Typically, the efficiency of an electrochemical cell decreases over its useful life. A "recovery protocol" is a reversal of this trend, restoring the efficiency of the cell to a higher value, effectively reversing the aging of the cell. The component may be part of an operating mode of a system, subsystem, stack, device, or battery. In other words, the component may be used during operation.

[0054] The component may be an additive. The additive may be added to a battery, a device, a stack, a system, or a combination thereof. For example, the additive may be an input stream additive, an output stream additive, a catalyst layer additive, a water recirculation loop additive. The additive may be added once or multiple times regularly, at predetermined intervals, during maintenance inspections, and the like. The additive may be added continuously to the input stream. For example, the continuous addition may have a relatively low additive concentration, about or at most about 10 mml / L, such as 1-15, 2-12, or 3-10 mml / L. In another non-limiting example, a higher concentration of additive may be added during discontinuous processing, such as occasionally added to an input stream or battery. The additive amount in the discontinuous process may be about or at least about 10 mmol / L, such as 10-100, 20-80, or 30-50 mmol / L.

[0055] The principles of the additives described herein can be applied to capture / remove / release any unwanted or undesirable ions, such as non-hydrogen ions, including but not limited to metal ions including iron (Fe 2+ , Fe 3+ ), halogen ions such as chloride ions (Cl-), alkali metal ions such as sodium (Na + ), alkaline earth metals such as calcium (Ca 2+ ), magnesium (Mg 2+ ), manganese (Mn 2+ ), chromium (Cr 3+ ), nickel (Ni 2+ ), other ions such as sulfate (SO4 2- )wait.

[0056] Figure 4 A non-limiting example of a system 100 is schematically shown that includes an electrochemical cell 50, a water source 52, which may carry impurities and pass through a purifier 54. The system also includes an additive source 56 that dispenses a predetermined amount of additive into the input stream. The additive may be added at the purifier 54, or added afterwards such that the additive is added to the purified input stream downstream of the source and purifier but upstream of the cell.

[0057] A controller 90 programmed as described herein is also depicted to aid in addition, metering of additives, analysis of ion presence, amount, etc. based on input (e.g., from one or more sensors), but is optional in the systems 100, 200, 300, 400 and other systems described herein. (One or more) sensors such as those represented by 92 may be part of the additive and / or system and are also optional. The placement of the controller and sensors in the figure is only schematic, indicating that they are present in the system.

[0058] Figure 5A non-limiting example of a maintenance cycle is schematically captured. During operation, the battery may be monitored for aging, health, additive levels, etc., or a combination thereof. If the additive concentration is within a predetermined amount, above a threshold concentration, the battery may continue to operate. If the additive concentration is below a threshold concentration or below a predetermined amount, the battery may be stopped from operating, flushed, the additive concentration may reach or exceed a threshold amount, or a combination thereof, before battery operation continues.

[0059] The additive may include, comprise, consist essentially of, or consist of one or more compounds named herein. The compound may include chelating agent(s), ionophore(s), fluorophore(s), precipitating agent(s), or a combination thereof.

[0060] The compound may include one or more ion chelators, chelating agents or ligands. Chelating agents are compounds that utilize chelation, which is a type of bonding of ions and molecules to metal ions. Chelation involves the formation or presence of two or more separate covalent bonds or coordination bonds between a ligand and a metal ion. Since metals are ions, the ions share electrons in the bond with the chelating agent. Electron sharing is important in the chelation mechanism of how chelating agents bind to metal ions. Chelating agents and metal ions can share electrons with each other, each of which provides an electron to form a bond, thereby forming a covalent bond. Alternatively, a chelating agent can be a chelating agent that provides two electrons to bind to the metal ion via a coordination bond.

[0061] Chelators are molecules that include one or more specific binding sites that have a high affinity for metal ions and are capable of binding to them. Chelators are highly specific for the target ion. Some chelators can bind to more than one type of ion.

[0062] The size, structure, spatial arrangement or steric effect of the atoms, or a combination thereof, can be a parameter that determines the selectivity of the chelator for the ion. For example, the size of the ring can be a parameter. If the binding energy of the chelator is tighter (lower energy) than the solvation energy in water, then the chelator is likely to displace water in the solvation shell.

[0063] Chelating agents can be configured to have selectivity or high affinity for one or more ions, and non-selectivity or low affinity for one or more different ions. For example, a chelating agent can be iron-binding. For example, a chelating agent can be configured to be non-binding to hydrogen ions (protons) to prevent or resist the destruction of the battery by protons (e.g., PEM electrolyzers). At the same time, a chelating agent can be configured to bind to metals to remove unwanted metal ions from the battery. For example, a chelating agent can be iron-binding.

[0064] The chelating agent configured to bind to the metal ion may have a selectivity coefficient, which is a numerical measure of the resolution of the chelating agent to interfering ions or ions that are not desired to be captured (in this case, hydrogen ions). The chelating agent disclosed herein may have a low selectivity coefficient, which means that the influence of interfering ions will have minimal influence on the function of the chelating agent to bind the metal ion. The selectivity coefficient = 1 is converted into an equivalent to metal ions and hydrogen ions, indicating that the response to metal ions and hydrogen ions is equal, <1 indicates that the responsiveness to metal ions is greater than the responsiveness to hydrogen ions, and >1 indicates that the responsiveness to hydrogen ions is greater than the responsiveness to metal ions. Therefore, the chelating agent disclosed herein should have a selectivity coefficient lower than 1.

[0065] Chelating agents may include receptors configured to chelate specific ions. Chelating agents may be configured to selectively capture one, at least one, or more than one ion in a single molecule or per additive molecule. Chelating agents may be configured to capture a metal ion between multiple additive molecules.

[0066] The pKa value of the chelating agent may be different from the pH of the operating cell. The pKa value may be greater or less than the pH of the operating cell. The value may be greater or higher than the pH by about or at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or more %. The greater the difference between the pH of the operating cell and the pKa value, the less likely the chelating agent will interfere with the hydrogen ions in the system.

[0067] For example, in a PEMFC where the pH is typically 0-4, the chelator may be configured not to react or chelate with hydrogen ions, thereby interfering with the operation of the cell, but rather to chelate iron ions (for example) to prevent the ions from damaging the membrane. Even if the chelator is flushed after a maintenance cycle, it is expected that some chelator molecules may remain, so the pKa (proton cycling) value of the chelator may interfere with the electrochemical activity of the cell if it is too close to the cell pH during operation.

[0068] Both pH and pKA are related to the acidity of a system. The symbol Ka represents the acid dissociation constant. pKa represents the dissociation of an acid. pKa is represented by the negative logarithm of Ka. Acids are classified as weak acids and strong acids. When in aqueous solution, strong acids dissociate into ions and weak acids partially dissociate, resulting in an equilibrium between the acid and its conjugate base. The dissociation of a weak acid HA can be written as follows: H + The logarithm of the reciprocal of concentration is pH.

[0069] pH indicates the acidity or alkalinity of a system. pH is the concentration of hydrogen ions in an aqueous solution. pH is a property of the solution, not of the molecule. In a working water-based electrochemical cell, the pH can be different than 7. For example, in a PEM fuel cell, the pH can be about 3. In a PEM electrolyzer, the pH can be about 2. In an alkaline KOH-based electrolyzer, the pH can be about 13. The pH gives the chemical potential of hydrogen - how much energy is required to produce hydrogen ions relative to other substances.

[0070] The pH value at which a chemical compound will absorb or donate a proton is called the pKa. The pKa is a chemical property of a molecule that describes the chemical potential at which hydrogen dissociates. For example, the pKa of a carboxylic acid (-COOH group) is close to 4. On the other hand, the pKa of a sulfonic acid (such as a typical Nafion group) can be closer to -1. Therefore, the pKa indicates that it is much easier to remove a proton from a sulfonic acid group than from a carboxylic acid group. Therefore, the pKa of an additive, or the chemical potential at which hydrogen dissociates, can be different from the pH of the solution.

[0071] In a non-limiting example, if the additive is citric acid, the suitability of the acid as an additive described herein will depend on the pH of the battery. Citric acid is a tricarboxylic acid with three carboxylic acid functional groups. The acid has three pKa values ​​when four hydrogens are dissociated, i.e., pKa=6.40, 4.76, and 3.13 (two of which are the same). If the fuel cell is operated at pH=2, the solution will have a large number of protons. Therefore, the citric acid will be completely protonated. If the battery is operated at pH=12, there will be a scarcity of protons in the solution, and the citric acid will be completely deprotonated. If the battery is operated at pH=3.13, one of the pKa values ​​of citric acid, the citric acid will have a proton attached to certain molecules and dissociate a proton on other molecules. This may interfere with the operation of the battery, in which it is desirable that the protons move freely in the solution rather than being bound to low-mobility macromolecules. By adding citric acid, the number of movable protons is therefore reduced, which is undesirable.

[0072] Capturing / releasing unwanted metal ions can further change the pKa of the additive molecule. Due to the capture / release interaction, the additive molecule can fluctuate between protonation and deprotonation. This is also undesirable because it can limit the number of mobile protons in the battery, which can interfere with the operation of the battery.

[0073] In another non-limiting example, a sulfonated tetrafluoroethylene based fluoropolymer-copolymer has the properties of a superacid catalyst due to the combination of the fluorinated backbone, the sulfonic acid groups, and the stabilization of the polymer matrix, making it an extremely strong acid with a pKa = -6. Therefore, the copolymer is mostly deprotonated within the operating range of the battery. Therefore, its pKa does not interfere with the operating pH of the battery.

[0074] Similarly, additives / chelators with a pKa of about 4 can capture metal ions in cells operating at a pH of about 2 without worrying about deprotonation reactions.

[0075] Thus, if the pH of the non-limiting exemplary operating cell is 0-4, the pKa of the additive should be outside the 0-4 pH range, such as below 0 or above 4.

[0076] Alternatively, the additive may have little or no protonated or deprotonated groups.

[0077] The one or more chelating agents may include one or more organic compounds. The chelating agent may include a single molecule, the size of which is adjusted to attract large ions. Alternatively, the chelating agent may include multiple chelating agents, the size of which is adjusted to coordinate around the ion to surround it.

[0078] The chelating agent may include an ether. The ether may be a crown ether, which is a cyclic ring containing a COC group. The COC group is unlikely to be protonated or deprotonated. Crown ethers are cyclic polyethers with four or more oxygen atoms, each separated by two or three carbon and / or nitrogen atoms. The general formula of a crown ether is (OCH2CH2) n or (OCH2CH2CH2) n The crown ether may include 4, 5 or 6 COC groups. The crown ether may include 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, azacrown ethers or combinations thereof. Other crown ethers are also contemplated.

[0079] Chelating agents may include carboxylic acid (-COOH) groups or their derivatives, such as EDTA (ethylenediaminetetraacetic acid). EDTA has carboxyl groups deprotonated at pKa = 0, 1.5, 2, 2.66. When added to a battery, some -COOH groups may include other ions, such as sodium, to simplify the binding to unwanted ions (such as Fe 2+ ) exchange.

[0080] The chelating agent may include an amine (—NH 2 ) group or a derivative thereof.

[0081] Chelating agents may include thujaplicins (isopropyl tropolones), such as hinokitiol, a natural terpenoid, which is a tropolone derivative containing an unsaturated seven-membered carbon ring. It is a monoterpenoid - cyclohepta-2,4,6-triene-1-one substituted with a hydroxyl group at the 2 position and an isopropyl group at the 4 position. It is an enol and a cyclic ketone derived from the hydride of cyclohepta-1,3,5-triene. Thujaplicins and tropolones have relatively high pKa (hinokitiol's pKa = 7), which is above the pH operating range of most cells considered herein.

[0082] The additives may include one or more ionophores. Ionophores are a class of compounds that form complexes with specific ions and facilitate their transport across the cell membrane. Ionophores may include hydrophilic pockets or pores that form binding sites for specific ions. Because ionophores can bind ions reversibly, they can be reused.

[0083] Additives having one or more ionophores structured to form complexes with specific unwanted ions can form newly formed metal complexes that are able to pass through the membrane and leave the cell. The newly formed metal complexes can be collected in the waste stream, cleaned of metal ions by applying an electrochemical potential, a temperature gradient, or adding molecules to the solution, and reused. Thus, unlike chelators, ionophores can be run through a cleaning cycle and reused.

[0084] The system can be connected to a maintenance loop to automatically add more additive during scheduled maintenance, or prompt the user to add more cleaning additive for maintenance. The additive can be drained or flushed periodically. The system can include a monitoring stage / (one or more) devices / (one or more) controllers for monitoring factors such as: ion concentration of the feed stream, additive ratio of the reaction, number of hours the cell has been operated, pH of the feed stream, etc. The collected input and data can be used to flush the system, add more additive, regenerate the additive, etc.

[0085] Figure 6A non-limiting example of a system including a reusable ionophore is schematically shown. System 200 includes a water source 52, which can introduce an input stream with impurities. The input stream can travel to a purifier 54 and then to a battery 50. System 200 can include a reusable additive, which can include an ionophore. The battery can include a selectively permeable membrane 58, through which newly formed complexes of ionophores and unwanted ions can pass. The newly formed complexes can travel to a regenerator 60, which can remove unwanted waste containing metal ions and release them from the system at point A. The cleaned ionophores can travel to an additive tank 56, from which the ionophores are added to the system as needed, predetermined, calculated, etc. The addition can be continuous, discontinuous, regular, irregular, periodic, maintenance, at various intervals, etc.

[0086] Alternatively or additionally, the ions may be captured, neutralized, bound by one or more compounds of an additive in the catalyst layer, the input stream, the output stream, anywhere within the water recirculation loop, or a combination thereof.

[0087] The system may include a sensor assembly configured to indicate, sense, measure, monitor, determine the presence and / or concentration of one or more unwanted ions. In other words, the sensor assembly may monitor how many ions have entered the system, stack, device, battery, or are present in the input stream.

[0088] A non-limiting example of a sensor assembly can be a chemical sensor. The chemical sensor can include an additive to which an indicator is added. The indicator can include a fluorophore attached to a chelated receptor. A fluorophore is a fluorescent chemical compound that is configured to re-emit light upon light excitation. A fluorophore can absorb and emit light within a certain wavelength range, referred to as an absorption or excitation and emission spectrum. Thus, a fluorophore absorbs light energy of a specific wavelength. Light absorption results in electronic excitation of the fluorophore. Then, when the electron returns to its ground state (unexcited state), the fluorophore re-emits the absorbed light energy at a different, longer wavelength.

[0089] Thus, the additive may include one or more chelating compounds, wherein at least some of the chelating compounds include a fluorophore attached to a chelating receptor via a spacer. The spacer may be an electron donating group, such as an amine. The electron donating group plays an important role in the sensing mechanism. The fluorophore may be constructed to be inert by default, so that when light is directed to the fluorophore, the material does not fluoresce. This effect is called photoinduced electron transfer (PET), in which the electron donating group quenches the natural fluorescence of the fluorophore. However, when the receptor is in contact with an unwanted guest or analyte ion (e.g., Fe 3+) binds, the charge interaction between the ion and the electron-donating group (e.g., amine) will undo the PET, thereby activating the fluorescence, and the fluorophore molecule will fluoresce when exposed to light of a specific wavelength.

[0090] Thus, the various components of the sensing compound act synergistically to have a first state, a second state, and a third state. The first state is an electron-free excited state of the fluorophore when the receptor of the sensing compound is not bound to the analyte ion. The second state is an electron-excited state of the fluorophore when the fluorophore electrons absorb light of a first wavelength when the receptor is bound to the analyte ion. The third state is a re-emission state of the absorbed light energy at a second wavelength when the electron returns to its ground state (unexcited state). The first and second wavelengths are different from each other.

[0091] A non-limiting exemplary structure of a sensing or chemical sensing component is shown in Figure 7 . Figure 7 A crown ether chelator (A) is shown, where the unwanted ion (B) is attached within the crown ether ring and a spacer (C) connects the chelated receptor to a fluorophore (D) with a binding site (E).

[0092] The sensor assembly can include a fluorophore-receptor moiety immobilized on a polymer surface as described herein. A non-limiting exemplary fluorophore can be 1,8 naphthalimide or a derivative thereof. The receptor can be a crown ether or a derivative thereof. An advantage of the disclosed sensor mechanism is that it can be optimized for a specific ion (e.g., iron) to the exclusion of other ions (e.g., protons or hydroxides) intended to be present in solution.

[0093] Alternatively, the sensor assembly may include a measurement of the total conductivity of the input or output water to measure the total ion content. For example, a known voltage may be applied between two electrodes in a water stream and the current may be measured. The current is proportional to the ionic conductivity of the water, which in turn is proportional to the number of ions dissolved in the water.

[0094] The fluorophore / receptor can be immobilized on a polymer surface. The polymer can include cellulose microparticles connected to a hydrogel (e.g., poly(2-hydroxyethyl methacrylate) or polyurethane). The combination of fluorophore-receptor molecules, cellulose, and hydrogel can be coated on a support layer (e.g., polyethylene terephthalate (PET)), followed by a drying and photocrosslinking stage to cure the hydrogel. The final fluorophore film can be made into a film with a thickness of about 50 μm-50 mm. The film can contain one fluorophore-receptor pair or more than one fluorophore-receptor pair.

[0095] The membrane can be incorporated into a sensing device. The sensing device can include an LED (e.g., blue) that produces optical excitation of electrons in the fluorophore. The LED emission can be optically filtered to prevent damage to the membrane or to enhance the signal-to-noise ratio. The fluorophore will fluoresce when excited, emitting light of a different frequency (e.g., green) that is proportional to the ion concentration in the solution. The emitted light can be further optically filtered to obtain a better signal-to-noise ratio or to prevent confusion with the LED frequency (e.g., blue). The emitted light can be directed to a photodiode and then digitized to provide the total ion concentration found. The sensing device can also include an electroactive polymer or a light source to induce the release of ions from the receptor. A schematic diagram of the sensing device connected to a power source and a battery is shown in Figure 8 .

[0096] The digital signal can be further processed to extract the calculated ion concentration using information about membrane manufacturing, lifetime to date, aging characteristics, etc. This can be further processed by a computing device or controller to assess the overall health of the electrochemical device and alert the user when maintenance or replacement actions are recommended. The measurements can be connected to a centralized hub or controller to process information from many such devices to predict the overall lifetime of multiple devices that may be located in the same or different locations.

[0097] Thus, the system, device or battery may include a sensing assembly including a fluorophore, a receptor, a light emitter and a light detector. The light emitter may be configured to emit light of a specific wavelength that can be absorbed by the fluorophore, such that the light absorption causes the electrons of the fluorophore to be excited. The light detector may be configured to detect light energy at a specific wavelength re-emitted from the fluorophore when the electrons of the fluorophore return to their ground state. The sensing assembly may be configured such that the amount of light detected is correlated or corresponds to the amount of (one or more) analyte ions in the sensor input.

[0098] The system, device or battery may also include one or more processors programmed to measure, monitor, identify, calculate or approximate the amount of metal ions detected by the sensor and / or additional sensor described herein. The processor may be programmed to receive input from one or more sensors (including chemical sensors described herein). The controller may be programmed to control, regulate, supply or a combination thereof in response to the received input, to a predetermined amount of an additive to the system, device or battery. The controller may be programmed to detect a signal from a photodetector and associate the input with the amount of metal ions present in the system, device, battery, input stream, output stream, water recirculation loop or a combination thereof.

[0099] The predetermined amount may be set or adjustable. The predetermined amount depends on system conditions, the type of input stream, the type of battery component material, system age, and / or other conditions. The output provided by the electrical device may be a number and / or data associated with the analyte, its quantity, or other information related to the analysis. In addition, the controller(s) may provide input to one or more devices (e.g., light emitters) to initiate light emission, terminate light emission, or both.

[0100] Additionally or alternatively, the additive may include a precipitant. The precipitant may be an acid that is configured to chemically interact, react, neutralize, or a combination thereof with the unwanted ions. The acid may be a weak acid having a pH less than 7 or about 4-6, or 4, 5, or 6. It is also contemplated that a strong acid may be used having a pH of about 1-4. Thus, the precipitant may have a pH of about 1-6 or 1, 2, 3, 4, 5, or 6. Thus, the unwanted ions react with the acidic additive to produce a neutral precipitate, such as a benign salt that can be flushed from the battery. The acid may precipitate the ions. The neutral precipitate should not cause degradation to the membrane and / or other components of the battery.

[0101] A weak acid is an acid that is not completely dissociated in a solution. The strength of a weak acid depends on the amount of its dissociation. The more it dissociates, the stronger the acid. The acid dissociation constant Ka is used to calculate whether an acid is a weak acid or a strong acid. Ka is a mathematical way to express the concentration of hydrogen dissociated from an acid. The smaller the Ka, the weaker the acid. A weak acid can be an acid tailored to the chemical properties of (one or more) unwanted ions. For example, if the input stream carries unwanted calcium (Ca), the weak acid can be citric acid (C6H8O7), which reacts with Ca to form calcium citrate Ca3(C6H5O7)2. Other suitable weak acids can include formic acid (HCOOH), acetic acid (CH3COOH), benzoic acid (C6H5COOH), hydrofluoric acid (HF), phosphoric acid (H3PO4), sulfurous acid (H2SO3), carbonic acid (H2CO3), nitrous acid (HNO2), hydrocyanic acid (HCN) or hydrosulfuric acid (H2S).

[0102] On the other hand, strong acids completely ionize in water to produce hydronium ions. Therefore, strong acid solutions contain H3O + The concentration of is equal to the initial concentration of the acid. Suitable strong acids may be sulfuric acid (H2SO4), nitric acid (HNO3) or other strong acids.

[0103] For the applications described herein, certain considerations need to be made when using acids. Certain acids (strong or weak) may be corrosive and degrade the electrochemical cell environment. On the other hand, due to the relative abundance and cost of weak acids, the use of acids (especially weak acids) can be economical.

[0104] As mentioned above and Figure 5As shown, the system can be connected to a maintenance loop to automatically add more additive during scheduled maintenance, or prompt the user to add more cleaning additive for maintenance. The system can include a monitoring phase to monitor factors such as: ion concentration of the feed stream, additive ratio of the reaction, number of hours the cell has been operated, pH of the feed stream, etc.

[0105] Additives comprising (weak) acids are particularly suitable for electrolyzers, in particular membrane-based electrolyzers. The electrolyzer has a water input via a pipe, which naturally leads to the release of ions into the input stream, for example from a steel pipe through which the water flows. This is different from, for example, a fuel cell, where the input cell does not contain liquid water and therefore there is less chance of releasing unwanted ions from the cell components into the input stream. The ions may attack the electrolyzer membrane, which, as mentioned above, is easily affected and can have a negative impact on the life of the cell. In addition, the ions may attack the catalyst, which may fall off and lead to efficiency losses.

[0106] Since impurities can damage components of a cell, such as catalysts and membranes, one generally strives to obtain input sources that are as pure as possible. Therefore, it is not obvious to utilize an input stream containing ions. However, purity requirements can be onerous, impractical, and uneconomical. Therefore, the additives disclosed herein provide a non-obvious method of using a variety of input streams without damaging cell components.

[0107] In addition, while the electrolyzer input water stream may include purified water, other water sources may also be utilized, including tap water, rainwater, and even seawater. The seawater may be characterized as water from the sea or ocean having a salinity of about, at least about, or at most about 3.5% or 35 g / L or ppm salt. The salt content may be about 1.5-4, 1.8-3.5, or 2.5-3.0%, or 15-40, 18-35, or 25-30 g / L or ppm. If the input water is seawater, the degree of ionization of the input stream is even higher, and the deionization technology may not be 100% effective, especially as the stack ages. Therefore, the addition of additives improves ion removal and can extend the life of the battery, device, stack, and / or system. The pH of the input water stream may be neutral or about 7 or between 5.2 and 9.5.

[0108] In at least one embodiment, the components configured to capture and / or remove ions can be stationary or fixed. Thus, instead of additives that can be included in an input stream or an output stream, compounds configured to capture, neutralize and / or release unwanted ions can be fixed on a surface. The surface can be a polymer surface. The surface can form a component within a battery, device, battery stack or system. The surface can be a surface of a battery component, such as a cathode catalyst layer, an anode catalyst layer, or a surface upstream of a battery.

[0109] In a non-limiting example, the additive may include a chelating agent, an ionophore, or both immobilized on the surface of the ion cleaner. The ion cleaner may be located downstream of the water source, the purifier, or both, and upstream of the electrolyzer cell. A schematic diagram of a non-limiting example of an ion cleaner is shown in Fig. 9 . Fig. 9 The system 300 includes an input stream source 52, a purifier 54, and a cell 50. Located upstream of the cell 50 is an ion cleaner 62, which includes a static, fixed additive configured to capture, neutralize, or sequester unwanted ions.

[0110] The ion cleaner may be maintained periodically. The cleaner may also include a refresh cycle to remove chelated ions and allow the chelation of new ions. The refresh cycle may be activated by chemical methods (e.g., washing with a solution of a specific pH), electrochemical methods (e.g., voltage), thermal methods, optical methods, vibration methods (e.g., using piezoelectric or electroactive polymers), or a combination thereof to remove chelated ions.

[0111] A non-limiting example of a maintenance cycle for a system including a fixed additive is schematically shown in Fig.10 and Fig.11 . Fig.11 Schematically shown is a chelating agent portion 70 on a support 72. During the process of unwanted ion capture in the cell, unwanted ions 74 bind to the chelating agent portion 70 on the support 72. During the renewal portion of the cycle, one of the activation types 76 is used to remove the ions 74 from the chelating agent portion 70. The ions 74 can be released into a waste stream 78.

[0112] Similar to fluorophore receptors immobilized on polymers, chelators / receptors can be immobilized on polymer surfaces. The polymer can include cellulose microparticles connected to a hydrogel (e.g., poly(2-hydroxyethyl methacrylate) or polyurethane). The combination of receptor molecules, cellulose, and hydrogel can be coated on a support layer (e.g., polyethylene terephthalate (PET)), followed by a drying and photocrosslinking stage to cure the hydrogel. The final membrane can be made into a thin film of about 50 μm-50 mm. The membrane can contain one receptor or more than one receptor. The membrane can be continuous or discontinuous on one or more surfaces of the cell. For example, the membrane can be a continuous layer on one side of the catalyst layer, which side can be directly adjacent to the membrane.

[0113] The fixed additive may be located upstream of the cell or within the cell. For example, the receptor may be contained in the catalyst layer(s), adjacent to or in close proximity to the membrane. Schematic examples of receptors in catalyst layers are shown in Fig.12 .exist Fig.12In FIG. 4 , membrane 32 is surrounded by anode catalyst layer 34 and cathode catalyst layer 36. Catalyst layers 34, 36 each include receptors 80, such as chelating agent receptors 80, which are configured to capture unwanted ions 74 that might otherwise attack membrane 32.

[0114] In one or more embodiments, the system or device may include multiple cells. These cells may receive water from a common or shared reservoir. The reservoir may be a tank, container, or basin. The input water stream entering the common reservoir may have been run through a deionizer / subsystem to remove unwanted ions. The deionizer may include one or more additives described herein.

[0115] A schematic diagram of a system with a common additive reservoir is shown in Fig.13 . Fig.13 The non-limiting exemplary system 400 shown in includes a common water reservoir 82, which contains an additive disclosed herein, which binds unwanted ions from an input stream. The system 400 also includes a plurality of cells 50, schematically shown or represented herein as a single cell 50. Upstream of the plurality of cells is a membrane 86. The membrane 86 can be a semipermeable, selective, or selectively permeable membrane that prevents the additive + ions (e.g., chelating agent-metal complex) from passing into the cell 50. The membrane 86 allows water molecules to pass. The non-limiting exemplary membrane can include a polymer (e.g., polymethacrylate 2-hydroxyethyl ester or polyurethane) having a pore size of about 1-10, 2-8, or 3-7 nm.

[0116] The additive + ions from the common reservoir 82 are moved to the deionization reservoir 84 via path A, where the additive is regenerated at B, and the cleaned regenerated additive is moved back to the common reservoir via path C. Unwanted ions are flushed out of the deionization reservoir 84 and the system 400. The regeneration step can be performed by chemical methods, thermal methods, electrochemical methods, or any other chemical methods. The deionization reservoir 84 can be located at the stack or at a different location.

[0117] Non-limiting exemplary additives can include short chain polymers, which can include the same backbone chemical composition as the hydrogel film or different chemical compositions. The molecular weight (MW) of the additive can be between 5 and 100, 10 and 90, or 20 and 80. Larger MW can prevent the ability of the additive to fully diffuse. Lower MW can allow the coordinated additive + ions to move through the film, which is undesirable. The additive can have a side chain that binds, captures, or electrochemically neutralizes ions in the solution. Non-limiting examples can be crown ethers that bind specific metal ions.

[0118] Disclosed herein is a method for slowing, reversing or inhibiting the aging process of an electrochemical cell. The method may include providing an additive to an input stream of the battery. The method may include incorporating the additive in such an amount or concentration to remove a threshold amount or concentration of (one or more) unwanted ions that cause or potentially cause battery degradation. The method may include providing an additive with a pKa or dissociation constant of a suitable additive based on the pH value or range of the battery during operation. The method may include selecting an additive that does not bind protons at a pH value or range of the battery during operation based on the (one or more) pKa value of the additive. The method may include providing the additive to the battery, device or system periodically, at regular intervals, during maintenance inspections, continuously, discontinuously, etc. The method may include supplying an additive that forms a metal complex, allowing the metal complex to pass through a membrane into a regenerator, releasing unwanted ions, and recovering or reusing the remaining additive in the system. The method may include providing an additive that is a precipitant, a weak acid, a chelating agent, an ion carrier, or a combination thereof.

[0119] The method may also include measuring, evaluating, monitoring, detecting or combining (one or more) analyte ions using a sensing assembly as described herein. The method may include providing a sensing assembly including a fluorophore and an acceptor attached by a spacer, the spacer being constructed to have a PET so that the electron-donating group of the spacer quenches the natural fluorescence of the fluorophore unless the analyte ion is attached to the acceptor. The method may include revoking the PET when the acceptor is combined with the guest analyte ion, thereby activating the fluorescence so that the fluorophore molecule fluoresces when exposed to light of a specific predetermined frequency. The method may include emitting light of a specific wavelength to excite the electrons of the fluorophore. The method may include detecting light of a specific wavelength re-emitted from the fluorophore when the electron returns to its ground state. The method may include translating, associating, calculating or approximating the amount of the detected light with the amount of (one or more) analyte ions present in the system, battery stack, device and / or battery. The method may include one or more processors that receive input from one or more sensors. The method may include one or more processors that provide input to one or more devices (e.g., light emitters).

[0120] The method may include removing (one or more) unwanted ions from a water circuit of a cell using (one or more) additive compounds immobilized on a surface. The method may include operating an input water stream through a cleaner having receptors on a surface configured to capture the unwanted ions. The method may include renewing the cleaner by activating the removal of ions from the additive by electrochemical, chemical, thermal, optical or vibrational methods.

[0121] The method may include using multiple cells and removing unwanted ions from the multiple cells. The removal may include having a single input stream that may contain unwanted ions. The method may include passing the single input stream through a common container, which may be configured as a deionization basin including an additive disclosed herein. The method may include capturing unwanted ions with the additive in the basin. The method may also include preventing the coordinated additive + unwanted ionic compounds from passing to the downstream of the basin by providing a semipermeable membrane, thereby allowing water molecules to pass and not allowing the coordinated additive + unwanted ionic compounds to pass. The method may include regenerating the additive in a deionization reservoir downstream of the basin. The method may include reusing the cleaned additive by returning the cleaned additive to the common reservoir. The method may include releasing ions from the system.

[0122] The processes, methods or algorithms disclosed herein may be delivered to or implemented by a processing device, a controller or a computer, which may include any existing programmable electronic control unit or a dedicated electronic control unit. Similarly, the processes, methods or algorithms may be stored as data and instructions executable by a controller or a computer in a variety of forms, including but not limited to information permanently stored on a non-writable storage medium (such as a ROM device) and information that can be modified and stored on a writable storage medium (such as a floppy disk, a tape, a CD, a RAM device, and other magnetic and optical media). The processes, methods or algorithms may also be implemented in a software executable object. Alternatively, the processes, methods or algorithms may be embodied in whole or in part using suitable hardware components (such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a state machine, a controller or other hardware components or devices) or a combination of hardware, software and firmware components.

[0123] The following applications are related to the present application: U.S. Patent Application Serial Nos. __________________ (RBPA 0432PUS, RBPA 0440PUS, RBPA 0442PUS, and RBPA 0448PUS), filed on ______________, the entire contents of which are incorporated herein by reference.

[0124] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms included in the claims. The words used in the specification are descriptive words rather than restrictions, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously mentioned, the features of various embodiments can be combined to form other embodiments of the present invention that may not be explicitly described or shown. Although various embodiments may have been described as providing advantages or being preferred in terms of one or more desired characteristics relative to other embodiments or prior art implementations, it is recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties, which depends on the specific application and implementation. These properties may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, in terms of one or more characteristics, to the extent that any embodiment is described as less desirable than other embodiments or prior art implementations, these embodiments are not outside the scope of the present disclosure and may be desirable for specific applications.

Claims

1. A hydrogen electrochemical system comprising: A battery comprising a membrane electrolyte and a catalyst layer loaded with a catalyst; and Deionization subsystem, which includes a selective binding chelator that binds one or more metal ions, the selective binding chelator having a pKa value(s) for its hydrogen dissociation(s) that is different from the pH value(s) at which the cell is operated, The deionization subsystem is located in the water recirculation loop of the cell.

2. The hydrogen electrochemical system of claim 1, wherein the pKa value(s) differ from the pH value(s) by at least 10%.

3. The hydrogen electrochemical system of claim 1, wherein the cell is an electrolyzer.

4. The hydrogen electrochemical system of claim 1, wherein the selective binding chelator comprises an iron ion receptor.

5. The hydrogen electrochemical system of claim 1, wherein the selective binding chelating agent comprises one or more carboxylic acid (-COOH) groups or derivatives thereof.

6. The hydrogen electrochemical system of claim 1, wherein the selective binding chelator comprises one or more thujasuline. 7 . The hydrogen electrochemical system according to claim 1 , further comprising a regeneration device configured to strip the bound one or more metal ions from the selective binding chelating agent.

8. The hydrogen electrochemical system according to claim 1, wherein the pH value of the system is 0-4, and the pKa value(s) is lower and / or higher than 0-4.

9. The hydrogen electrochemical system of claim 1, wherein the deionization subsystem is located in at least one catalyst layer of the cell.

10. An electrolyzer system comprising: a water input source that supplies a water input stream; an electrolyzer cell located downstream of the water input source, comprising a membrane electrolyte and a catalyst layer loaded with a catalyst; and A deionization subsystem located upstream of the electrolyzer cell and downstream of the water input source includes a chelating agent that binds one or more non-hydrogen ions present in the water input stream, the chelating agent having a pKa value different from any pH value of the electrolyzer in operation.

11. The electrolyzer system of claim 10, wherein the chelating agent is deprotonated within the operating range of the cell.

12. The electrolyzer system of claim 10, wherein the chelating agent has an iron ion receptor.

13. The electrolyzer system of claim 10, wherein the chelating agent comprises one or more carboxylic acid (-COOH) groups or derivatives thereof.

14. The electrolyzer system of claim 10, wherein the chelating agent comprises one or more thujasuline.

15. The electrolyzer system of claim 10, further comprising a regeneration device configured to strip the bound one or more non-hydrogen ions from the chelating agent.

16. The electrolyzer system of claim 10, wherein the pH of the electrolyzer in operation is about 2, and the pKa value is above or below 2.

17. An electrolytic cell deionization device, comprising: A reservoir with a chelating agent having one or more dissociation constant pKa values ​​that are above or below the pH of the operating electrolyzer cell such that the proton volume in the electrolyzer cell remains unreduced in the presence of the chelating agent.

18. The electrolyzer deionization apparatus of claim 17, wherein the chelating agent is deprotonated within the operating range of the electrolyzer cell.

19. The electrolytic cell deionization apparatus of claim 17, wherein the chelating agent comprises one or more thujasuline.

20. The electrolyzer deionization apparatus of claim 17, wherein the electrolyzer deionization apparatus is located upstream of the electrolyzer cell.

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