DETIONIZATION SYSTEM FOR AN ELECTROCHEMICAL CELL

Abstract

An electrochemical hydrogen stack contains a plurality of electrochemical hydrogen cells, a common water inlet source upstream of the plurality of electrochemical hydrogen cells, wherein the common water inlet source contains a water stream with metal ions, and a deionization additive source containing a deionization additive that selectively binds the metal ions and does not bind to hydrogen ions.

Description

TECHNICAL FIELDThe present disclosure relates to deionization components, systems, subsystems and methods in electrochemical cells, particularly electrolyzers and fuel cells.BACKGROUNDHydrogen technologies such as fuel cells and electrolyzers are becoming increasingly popular due to their ability to generate and store clean energy. Nevertheless, there are still many challenges that make industrial production difficult. In addition to the demanding environmental conditions in fuel cells and electrolyzers, which make the selection of materials more difficult, the degradation of components such as catalysts and membranes must also be eliminated, since the degradation impairs the efficiency of the hydrogen devices.SUMMARYIn one embodiment, an electrochemical hydrogen stack is disclosed. The stack may include a plurality of electrochemical hydrogen cells, a common water input source upstream of the plurality of electrochemical hydrogen cells, the common water input source including a water stream including metal ions, and a deionization additive source including a deionization additive that selectively binds the metal ions and does not bind hydrogen ions. The water stream may be a seawater stream having a salt concentration of about 15-35 mg / L. The electrochemical hydrogen stack may further include a regenerating device connected to a deionization additive source. The electrochemical hydrogen stack may further include a water permeable membrane impermeable to additive bound ions. The deionization additive can be a chelating agent. The deionization additive may have a dissociation constant value that is different from a pH of the electrochemical hydrogen stack operated. The electrochemical hydrogen stack may further include an ion additive impermeable membrane, wherein both the deionization additive and the membrane include a hydrogel. The electrochemical cells may be electrolysers.In another embodiment, a deionization cycle of an electrolyser stack is disclosed. The deionization cycle of an electrolyser stack may include a water source releasing a water stream containing metal ions, a deionization additive source downstream of the water stream, the deionization additive removing the metal ions from the water stream by chemically bonding the metal ions upstream of an electrolyser stack, a water permeable membrane disposed between the electrolyser stack and the deionization additive source, and an additive regenerating device disposed downstream of the water permeable membrane and upstream of the water source. The deionization additive can be an ionophore. The deionization additive can be a chelating agent containing a metal ion receptor. The metal ions may be iron ions. The water permeable membrane may include a hydrogel. The water permeable membrane and the deionization additive may have a different chemical composition. The water permeable membrane may be impermeable to the additive. The regeneration device may be an electrochemical regeneration device.In another embodiment, a deionization system of a fuel cell stack is disclosed. The stack may include a plurality of fuel cells, each fuel cell including a membrane adjacent catalyst layers and an immobilized deionization additive disposed in the catalyst layers, wherein the immobilized deionization additive includes a plurality of receptors that selectively bind metal ions while not binding protons. The fuel cell stack may have a common regeneration cycle for the plurality of fuel cells to remove bound metal ions from the fuel cell stack. The immobilized deionization additive can contain cellulose microparticles linked to a hydrogel. The metal ions may contain iron ions. The immobilized deionization additive can be a continuous film having a thickness of about 50 μm to 50 mm.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is an exploded perspective view of an example non-limiting cell; FIG. 2 is a schematic illustration of an electrolyser and its mode of operation; FIG. 3 is a schematic illustration of a non-limiting example of an electrochemical system that contains undesired ions in the input stream entering the cell; FIG. 4 is a schematic illustration of a non-limiting example of an electrochemical system that includes undesired ions and an additive configured to trap the ions; FIG. 5 is a non-limiting example of a cycle of servicing an electrochemical cell that includes an additive configured to remove undesired ions from the input stream; FIG. 6 shows another example, non-limiting, system for removing unwanted ions that includes a reusable ionophore; FIG. 7 is a non-limiting example of a chemical structure of a chemosensor disclosed herein; FIG. 8 shows a schematic illustration of a non-limiting example of sensor device components connected to a power source and a cell; FIG. 9 shows an example non-limiting system including an additive for removing undesired ions and an ion cleaner; FIG. 10 is a schematic, non-limiting example of a maintenance cycle of an immobilized additive system; FIG. 11 is a schematic illustration of trapping and releasing undesired ions according to one or more embodiments disclosed herein; FIG. 12 is a schematic, non-limiting example of the additive receptors in the cell catalyst layers; and FIG. 13 is a schematic illustration of an example, non-limiting system including a cell stack and a common additive reservoir.DETAILED DESCRIPTIONEmbodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present embodiments. As those skilled in the art will appreciate, various features illustrated and described with reference to one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not expressly illustrated or described. The depicted combinations of features represent representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure could be desired for particular applications or implementations.Except in the examples, or where expressly stated otherwise, all numerical quantities in this specification indicating amounts of material or conditions of reaction and / or use are to be understood as modified by the word "about" to describe the broadest scope of the invention. Use within the stated numerical limits is generally preferred. Unless expressly stated otherwise, percentages, "parts of", and ratio values are by weight; the description of a group or class of materials as suitable or preferred for a particular purpose in the context of the invention implies that mixtures of two or more members of the group or class are equally suitable or preferred; the description of components in chemical terms refers to the components at the time of addition to a combination given in the description and does not necessarily exclude chemical interactions between the components of a once mixed mixture.The first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation in this document and applies mutatismutantly to normal grammatical variations of the originally defined abbreviation. Unless expressly stated otherwise, measurement of a property is determined by the same technique previously or later referred to for the same property.It is also to be understood that the singular forms "a", "an" and "the" used in the specification and the appended claims include plural referents unless the context clearly indicates otherwise. For example, when a component is mentioned in the singular, this is intended to mean that a multiplicity of components is included.As used herein, the term "substantially," "generally," or "about" means that the amount or value in question may be the specified specific value or another value in its vicinity. In general, the term "about" that denotes a particular value is intended to denote a range within + / - 5% of the value. An example: The term "about 100" denotes a range of 100+ / -5, i.e., the range of 95 to 105. In general, using the term "about" it can be understood that similar results or effects can be obtained according to the invention within a range of + / - 5% of the stated value. The term "substantially" may modify a value or relative feature disclosed or claimed in the present disclosure. In such cases, "substantially" may mean that the value or relative property it modifies is within ± 0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, or 10% of the value or relative property.It should also be noted that integer ranges expressly include all intervening integers. For example, the integer range 1-10 expressly includes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. 97, 98, 99, 100. Similarly, in specifying an arbitrary range, intermediate numbers which are increments of the difference between the upper limit and the lower limit divided by 10 may be used as alternative upper or lower limits. For example, when 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 may be selected as the lower or upper limit.In the examples set forth herein, concentrations, temperatures, and reaction conditions (e.g., pressure, pH, flow rates, etc.) can be carried out with plus or minus 50 percent of the stated values, rounded or truncated to two significant sites of the value stated in the examples. In a refinement, the concentrations, temperature, and reaction conditions (e.g., pressure, pH, flow rates, etc.) may be carried out with plus or minus 30 percent of the stated values, rounded or truncated to two significant sites of the value stated in the examples. In a further refinement, the concentrations, temperature, and reaction conditions (e.g., pressure, pH, flow rates, etc.) may be carried out at plus or minus 10 percent of the stated values, rounded or truncated to two significant locations of the value stated in the examples.For all compounds given as empirical chemical formula with multiple letters and numerical indices (e.g., CH 2 O), the values of the indices may be plus or minus 50% of the given values, rounded or truncated to two significant locations. For example, when CH 2 O is given, this means a compound of formula CHO (0,8-1,2)(1,6-2,4)(0,8-1,2). In a refinement, the values of the indices may be plus or minus 30 percent of the stated values, rounded or truncated to two significant locations. In a further refinement, the values of the indices may be plus or minus 20 percent of the stated values, rounded or truncated to two significant locations.As used herein, the term "and / or" means that either all or only one of the elements of the group may be present. For example, "A and / or B" means "A only, or B only, or both A and B.". In the case of "A only", the term also includes the possibility that B is absent, i.e. "A only, but not B".It is also to be understood that this invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may, of course, vary. Moreover, the terminology used herein is used for the purpose of describing particular embodiments of the present invention only and is not intended to be limiting in any way.The term "comprising" is synonymous with "including", "having", "containing" or "characterized by". These terms are inclusive and open-ended and do not exclude additional elements or process steps not listed.The phrase "consisting of" excludes any element, step, or component not recited in the claim. When this phrase appears in a clause of the main part of a claim and not immediately after the preamble, it only limits the element mentioned in this clause; further elements are not excluded from the claim as a whole.The phrase "consisting essentially of" limits the scope of a claim to the materials or steps set forth, as well as to those that do not materially affect the basic feature(s) and novel feature(s) of the claimed subject matter.As regards the terms "comprising", "consisting of", and "consisting essentially of", the presently disclosed and claimed subject matter, when one of these three terms is used herein, can include the use of either of the other two terms.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.The description of a group or class of materials as suitable for a particular purpose in connection with one or more embodiments implies that mixtures of two or more members of the group or class are also suitable. The description of the components in chemical terms refers to the components at the time of addition to a combination indicated in the description and does not necessarily exclude chemical interactions between the components of the mixture after mixing. The first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation and applies mutatismutantly to normal grammatical variations of the originally defined abbreviation. Unless expressly stated otherwise, measurement of a property is determined by the same technique previously or later referred to for the same property.Electrochemical cells such as fuel cells that convert the chemical energy of a fuel (e.g., H 2) and an oxidizing agent into electricity by two electrochemical half reactions (redox reactions) have become an increasingly popular technology. Fuel cells are today a promising alternative drive technology, which manages without emissions of toxicants or greenhouse gases. One of the current obstacles to the wide spread of this clean and sustainable technology is clean production of the H 2- fuel.Fuel cells provide an environmentally friendly alternative to internal combustion engines for a variety of vehicles such as cars and buses. A fuel cell generally has a relatively high efficiency and a high power density. A very attractive feature of the fuel cell engine is no carbon emissions provided the hydrogen has been recovered in an environmentally friendly manner. The fuel cell is not only an environmentally friendly motor, but can also be used in other applications such as stationary and portable power sources.However, fuel cell technology introduces a number of challenges associated with maintenance, persistent performance over time, longevity, and production costs. For example, the fuel cell is exposed to a highly corrosive environment that requires materials that can withstand the severe conditions. While the focus is on the overall performance of the fuel cells, stepwise improvements of the individual components of the fuel cell are required.A non-limiting example of a PEMFC is shown in FIG. 1. A core component of the PEMFC 10 that contributes to the generation of the electrochemical reaction required for the separation of the electrons is the membrane electrode assembly (MEA) 12. In addition to the MEA 12, the PEMFC 10 typically includes other components such as current collectors 14, gas diffusion layer(s) 16, gaskets 18, and bipolar plate 20 and bipolar plates 20, respectively.In fuel cells, the electrolyte moves charged ions between the cathode and the 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. As electrolyte, an organic membrane can be used because it can move ions at low temperatures, is cheaper than inorganic electrolytes, and can be made as a thin layer (1 μm - 1 mm, typically about 5-50 μm).Another type of electrochemical cell, an electrolyser, also utilizes the movement of protons through a membrane and the flow of electrons through an external circuit, such as a fuel cell. Therefore, a proton exchange membrane (PEM) electrolyser stack may be used as the MEA. However, the direction of reactions and energy flow in electrolyzers is opposite to that in fuel cells. While a fuel cell consumes hydrogen and oxygen to generate current and water, an electrolyser is an electrochemical device that converts current and water into hydrogen and oxygen.A representation of the electrolysis principle used by a PEM electrolyser with the corresponding reactions is shown in Figure 2. The electrolyser 30 contains the PEM 32, the anode 34, and the cathode 36. The reactant, liquid water (H 2 O), passes through the porous transport layer (PTL) of the anode 34 to the anode catalyst layer where the oxygen evolution reaction (OER) takes place. The protons (H +) migrate through the PEM 32, and electrons (e-) are conducted through an external circuit at the catalyst layer of the cathode 36 during the hydrogen evolution reaction (HER). The anodic OER requires a much higher overpotential than the cathodic HER. It is the anodic OER which determines the efficiency of water splitting due to the sluggish character of four-electron transfer.Various materials are used for the manufacture of the electrolyser 30. An example of the anode PTL sheet material may be titanium (Ti), and the cathode PTL sheet may be carbon-based materials such as carbon paper, carbon nonwoven fabric, etc. The PEM 32, anode 34, and cathode 36 may be surrounded by flow field, bipolar, or separator plates, which may be, for example, Ti, or gold or platinum coated Ti metals.Catalysts are typically used on anode 34 and cathode 36 to support the semi-reaction processes. The typical catalyst material on cathode 36 is platinum (Pt), while the typical catalyst used on anode 34 is ruthenium (Ru), iridium (Ir), Ir-Ru, ruthenium oxide (RuO 2), iridium oxide (IrO 2) or iridium-ruthenium oxide (Ir-Ru-O), as a combination of relatively high activity and durability is thereby achieved.Overall, an electrolyser splits water into electrons, smaller ions (protons in PEM or hydroxide in AEM), and molecules (oxygen and hydrogen gas) so that electrons can flow into the external circuit. A fuel cell generates water from hydrogen or oxygen gas, wherein electrons are consumed in the process. Often, the membrane contains water, which corresponds to water production (in a fuel cell) or water consumption (in an electrolyser). The wetted membrane typically has better ion transport properties and a longer life than a dry membrane. The comparative reactions of a fuel cell and an electrolyser are shown in Table 1 below: Table 1 - Reactions of the fuel cell and the electrolyser at the anode and cathode Table 1 - Reactions of the fuel cell and the electrolyser at the anode and cathodeElectrolysersPEM2 H 2 O → O 2 + 4 H + + + 4e -4 H + + 4 e - → 2 H 2AEM4 OH-->O 2 + 2 H 2 O+4e--4 H 2 O + 4e - > 2H 2 + 4 OH -A fuel cellPEM2 H 2 → 4H + + 4e -O 2 + 4 H + + + 4 e - > 2 H 2 OAEM2 H 2 + 4 OH-->4 H 2 O+4e--O 2 + 2 H 2 O + 4e ->4 OH --A fuel cell and an electrolyser may be used together to store energy by means of hydrogen. The electrolyser can be used for industrial, private and military applications and for technologies for energy storage, for example for stabilizing the power grid by dynamic power sources such as wind turbines and solar cells or for local hydrogen production for industrial and other purposes.The efficiency of an electrochemical cell is closely related to the efficiency with which the ions travel through the electrolyte. If it is difficult for the ions to move through the electrolyte, i.e., if the ionic resistance is higher, a higher electrochemical potential is required for a fixed current, resulting in lower efficiency. The ionic resistance of the electrolyte is approximately proportional to its thickness. It is therefore desirable that the electrolyte be as thin as possible. At the same time, the electrolyte must be chemically resistant to prevent or resist degradation (the deionization system of a fuel cell stack of claim 17) and mechanically robust to prevent mechanical degradation during operation of the cell over the entire desired life.Degradation of the membrane may be caused by various factors. A catalyst for the degradation of the membrane is, for example, metal ions which can diffuse into the electrolysis cell. A metal ion may be surrounded by a water solvate shell. Metal ions may originate from impurities in the input stream, from the dissolution of atoms from the steel components of the electrochemical device, from the decomposition of catalyst materials, etc. For example, if the electrochemical device is an electrolysis stack, insufficient cleaning of the input water may result in some ions remaining as they enter the cell, as schematically illustrated in FIG. 3. In the figures shown herein, the term impurities is used to refer to undesired ions. Referring now to FIG. 3, there is shown an input stream from water source 52 which may contain water and impurities in the form of ions. As the water stream flows through a purifier 54, some ions may be present and become a potential source for degradation of the membrane.The ions may diffuse into the membrane, which may lead to side reactions and chemical degradation. A non-limiting example of a side reaction is the oxidation of a hydroxide (OH) ion to a hydroxyl (·OH) radical, such as: Fe 3++ OH - → Fe 2++ ·OH. The hydroxyl radical is known to be a key component in many forms of degradation of the membrane because it is chemically reactive and therefore attacks bonds within the polymer, leading to degradation. Other ions present in the cell may be involved in electrochemical side reactions which reduce the efficiency of the cell. Thus, Fe ions, and other unwanted ions, must be prevented from diffusing into the membrane and must be captured and / or passivated if they do.In one or more embodiments, a system is disclosed. The system may include one or more devices that include an electrochemical cell. The electrochemical cell may be a hydrogen cell. The electrochemical cell can be a fuel cell or an electrolyser, referred to below as a cell. The cell may be a membrane cell. In a non-limiting example, the cell may be a polymer electrolyte membrane (PEM) electrolyser or an anion exchange membrane (AEM) electrolyser. The system may further include a component for ion removal or deionization from the system. The removal may be from the water recirculation loop of the cell, including, but not limited to, the input stream, the output stream, the catalyst layer(s), or a combination thereof.The component may include, or be part of, a "recovery protocol" for the cell, device, or system. Normally, the efficiency of an electrochemical cell decreases over its life. A "restore 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 the system, subsystem, stack, device or cell. In other words, the component may be used during operation.The component may be an additive. The additive may be added to the cell, the device, the stack, the system, or a combination thereof. The additive may be, for example, an input stream additive, an output stream additive, a catalyst layer additive, or an additive for the water recirculation loop. The additive may be added once or more times, regularly, at predetermined intervals, during maintenance checks or the like. The additive may be added continuously to the input stream. For example, the continuous addition may have a relatively low concentration of the additive, such as or at most about 10 mml / L, such as 1-15, 2-12, or 3-10 mml / L. In a further non-limiting example, a higher concentration of the additive may be added during a non-continuous treatment, such as an occasional addition to the input stream or cell. The amount of additive in the non-continuous treatment may be about or at least about 10 mmol / L, such as 10-100, 20-80, or 30-50 mmol / L.The principles of the additive described herein can be applied to the trapping / removal / liberation of undesired ions, such as, for example, non-hydrogen ions including, but not limited to, metal ions including iron (Fe 2+, Fe 3+), halogen ions such as chloride (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 (SO 42-) etc.FIG. 4 schematically shows a non-limiting example of a system 100 that includes an electrochemical cell 50 and a water source 52 that may bring contaminants with it and that passes through a cleaner 54. The system further includes an additive source 56 that distributes a predetermined amount of additive into the input stream. The additive may be added at the point of the purifier 54 or thereafter such that the additive is added to the purified input stream downstream of the source and purifier but upstream of the cell.A controller 90, programmed as described herein to assist in the addition, dosage of the additive, analysis of the presence, amount of ions, etc., based on inputs, e.g., from one or more sensors, is also depicted, but is optional in systems 100, 200, 300, 400, and other systems described herein. The sensor(s), such as those labeled 92, may be part of the additive and / or systems, and are also optional. The arrangement of the controller and sensor / sensors in the figures is only schematic and indicates their presence in the system.In FIG. 5, a non-limiting example of a maintenance cycle is schematically depicted. During operation, the cell may be monitored for aging, condition, amount of additive, or a combination thereof. If the additive concentration is within a predetermined amount, i.e., above a threshold concentration, the cell may continue to be operated. If the additive concentration is below a threshold concentration or below a predetermined amount, the cell may stop operation, be flushed, the concentration of additive may be brought to or above a threshold amount, or a combination thereof, before operation of the cell continues.The additive may contain, comprise, consist essentially of, or consist of one or more of the compounds mentioned herein. The compounds may include chelator(s), ionophore(s), fluorophore(s), precipitants, or a combination thereof.The compounds may contain one or more ion chelators, chelating agents, or ligands. Chelating agents are compounds that utilize chelating, a manner of binding ions and molecules to metal ions. Chelating includes the formation or presence of two or more separate covalent or coordinative bonds between a ligand and a metal ion. Since metals are ions, the ions share electrons in the linkage with the chelator. Sharing of electrons is important to the chelating mechanism in binding chelators to metal ions. The chelator and the metal ion may share the electrons, both providing an electron for forming the bond, thus forming a covalent bond. Alternatively, the chelator may be the one that provides two electrons to bind the metal ion via a coordinative bond.Chelators are molecules that have and can bind one or more specific binding sites with high affinity for metal ions. Chelators have a high degree of specificity for a target ion. Some chelating agents may bind to several types of ions.The size, structure, spatial arrangement of atoms or steric effects, or a combination thereof may be the parameters that determine how selective a chelator is to ions. For example, a size of a ring may be a parameter. If the binding energy of the chelator is lower (lower energy) than the solubilization energy in water, the chelator is likely to take up the place of water in the solubilization shell.The chelating agents may be configured to be selective for or have high affinity for one or more ions, while being non-selective for or have low affinity for one or more other ions. The chelator is thus a selectively binding chelator. The chelator may be designed, for example, to be non-binding to hydrogen ions (protons) to prevent or avoid interference from cells using protons, such as a PEM electrolyser. At the same time, the chelator may be configured to be metal-binding to remove undesired metal ions from the cell. The chelator may be, for example, iron-binding.The chelator, which is designed to bind to metal ions, may have a selectivity coefficient that is a numerical measure of how well the chelator can distinguish interfering ions from ions that are not desired to be captured, in this case hydrogen ions. The chelator disclosed herein can have a low selectivity coefficient, meaning that the influence of the interfering ion has minimal effects on the chelator's function to bind to metal ions. The selectivity coefficient = 1 means an equivalent reaction to the metal ion and the hydrogen ion, <1 means a stronger reaction to the metal ions than to the hydrogen ions, and >1 means a stronger reaction to the hydrogen ions than to the metal ions. The chelator disclosed herein should therefore have a selectivity coefficient of less than 1.The chelator may contain a receptor configured to chelate a particular ion. The chelator can be configured to selectively capture one, at least one, or more than one ion in a single molecule or per additive molecule. The chelator may be configured to capture a metal ion between multiple additive molecules.The chelator pKa / pKa may / may be different from the pH of an operating cell. The pKa(s) may / may be greater than or less than the pH of an operating cell. The values may be greater or greater by 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or greater in % or greater, or at least about so. The greater the difference between the pH of an operating cell and the pKa(s), the less likely interference between the chelator and the hydrogen ions in the system.In a PEMFC, which typically has a pH of 0-4, the chelator may be configured, for example, not to react with or chelate hydrogen ions and thus interfere with the operation of the cell, but to chelate an iron ion (for example) to prevent the ion from damaging the membrane. Even if the chelator is flushed out after a maintenance cycle, it is believed that some chelator molecules remain, so that the chelator's pKa (proton cycle) may affect the electrochemical activity of the cell if the values are too close to the cell's pH during operation.Both pH and pKA relate to the acidity of a system. The symbol Ka denotes the acid dissociation constant. pKa denotes the dissociation of an acid. pKa is represented by the negative logarithm of Ka. Acids are classified as weak and strong acids. As strong acids break down into ions in aqueous solutions, weak acids partially dissociate, resulting in an equilibrium between the acid and its conjugated base. Dissociation of a weak acid HA can be described as follows: HA ↔ A -+ H +. The logarithm of the reciprocal of the concentration of H + is the pH.The pH denotes the acidity or basicity of a system. The pH is the concentration of hydrogen ions in an aqueous solution. The pH is the property of a solution rather than a molecule. In a functioning water-based electrochemical cell, the pH may be different from 7. In a PEM fuel cell, the pH may be about 3, for example. In a PEM electrolyser, the pH may be about 2. In an alkaline KOH-based electrolyser, the pH may be about 13. The pH indicates the chemical potential of the hydrogen - how much energy it costs to have hydrogen ions compared to something else.The pH at which a chemical compound takes in or releases protons is referred to as pKa. pKa is a chemical property of a molecule that describes at which chemical potential the hydrogen dissociates. For example, carboxylic acids (-COOH groups) have a pKa value close to 4; sulfonic acids (such as a typical Nafion group), on the other hand, have a pKa value closer to -1. Thus, the pKa indicates that it is much easier to remove the proton from a sulfonic acid group than from a carboxylic acid group. Thus, the additive may have a pKa or chemical potential at which the hydrogen dissociates, which is / is different from the pH of the solution.In a non-limiting example, if the additive were citric acid, the suitability of the acid as an additive described herein would depend on the pH of the cell. Citric acid is a tricarboxylic acid having three carboxylic acid functional groups. The acid has three pKa values at which the four hydrogen atoms dissociate, i.e., pKa = 6.40, 4.76, and 3.13 (two of which are the same). When a fuel cell is operated at pH=2, the solution contains many protons. Thus, the citric acid is completely protonated. When a cell is operated at pH=12, there are few protons in the solution and the citric acid is completely deprotonated. When a cell is operated at pH=3.13, one of the pKa values of citric acid, the citric acid will have a proton that is bound to some molecules and dissociated to others. This could impair the operation of the cell, as it is desirable that the protons in the solution move freely and are not bound to larger molecules with low mobility. By adding citric acid, the inventory of mobile protons is reduced, which is undesirable.The capture / liberation of the undesired metal ions can further alter the pKa of the additive molecules. Due to the capture / release interaction, the molecules of the additive may vary between protonation and deprotonation. This is also undesirable because it can limit the existence of mobile protons in the cell, which can impair the operation of the cell.Another non-limiting example is a sulfonated tetrafluoroethylene-based fluoropolymer copolymer that has the property of a superacid catalyst due to the combination of the fluorinated backbone, the sulfonic acid groups and the stabilizing effect of the polymer matrix, making it a very strong acid with pKa= -6. The copolymer is therefore largely deprotonated within the operating range of the cell. Its pKa thus does not affect the operating pH of a cell.Similarly, an additive / chelator having a pKa of about 4 can capture metal ions in a cell operating at a pH of about 2 without fear of deprotonation reactions.Thus, if the pH of a non-limiting operating cell is 0-4, the pKa of the additive should be outside the pH range of 0-4, e.g., lower than 0 or higher than 4.Alternatively, the additive may also have groups which are only minimally protonated or non-protonated or deprotonated.The one or more chelating agents may contain one or more organic compounds. The chelator may contain a single molecule sized to attract a large ion. Alternatively, the chelator may include a plurality of chelators sized to coordinate around and surround an ion.The chelator may contain an ether. The ether may be a crown ether, i.e. a cyclic ring containing C-O-C groups. The C-O-C groups are likely not protonated or deprotonated. Crown ethers are cyclic polyethers having four or more oxygen atoms, each separated by two or three carbon and / or nitrogen atoms. Crown ethers have a general formula of (OCH 2 CH 2)n or (OCH 2 CH 2 CH 2)n. The crown ether may contain 4, 5 or 6 C-O-C groups. The crown ether may include 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, aza-crown ether, or a combination thereof. Other crown ethers are contemplated.The chelator may contain carboxylic acid (-COOH) groups or derivatives thereof such as EDTA (ethylene diamine tetraacetic acid). EDTA has a carboxyl deprotonation at pKa = 0, 1.5, 2, 2.66. Some of the -COOH groups may contain other ions such as sodium at the time of addition to the cell to facilitate exchange with undesired ions such as Fe 2+.The chelator may contain amine (-NH 2) groups or derivatives thereof.The chelator may contain thuringiensiss (isopropyl cycloheptatrienolones), such as hinokitiol, a natural terpenoid, a tropolone derivative containing an unsaturated seven membered carbon ring. It is a monoterpenoid cyclohepta-2,4,6-trien-1-one substituted with a hydroxy group at position 2 and an isopropyl group at position 4. It is an enol and a cyclic ketone derived from a hydride of a cyclohepta-1,3,5-triene. Thujaplicins and tropolones have a relatively high pKa (hinicitiol has a pKa of 7) which is above the pH operating range of most of the cells considered here.The additive may contain one or more ionophores. Ionophores are a class of compounds that form complexes with certain ions and facilitate their transport through cell membranes. Ionophores can contain a hydrophilic pocket or hole that forms a binding site for a particular ion. Since ionophores can reversibly bind ions, they can be reusable.An additive having one or more ionophores that are designed to complex with certain undesirable ions can form a newly formed metal complex that can pass through the membrane and leave the cell. The newly formed metal complex can be collected in a waste stream, purified from the metal ion by applying an electrochemical potential, a temperature gradient, or by adding molecules in the solution, etc., and reused. Unlike the chelating agent, the ionophore can undergo a cleaning cycle and be reused.The system may be associated with a maintenance cycle that automatically adds more additive at the periodic maintenance or prompts the user to add more cleaning additive for maintenance. The additive may be regularly drained or flushed out. The system may include a monitoring phase / device(s) / controller(s) that control elements such as: the ion concentration of the stream, the amount of additive that is reacted, the number of hours the cell was operated, the pH of the stream, etc. The collected inputs and data may be used to purge the system, add more additive, regenerate the additive, etc.FIG. 6 schematically shows a non-limiting example of a system including a reusable ionophore. The system 200 includes a water source 52 that can introduce an input stream with contaminants. The input stream may enter the purifier 54 and then the cell 50. The system 200 may include an additive that may be reused, where the additive may include an ionophore. The cell may include a selectively permeable membrane 58 that can pass through a newly formed complex of the ionophore and an undesired ion. The newly formed complex can pass through a regenerator 60 (refresher 60) which removes the undesired waste materials containing metal ions and releases them from the system at point A. The clean ionophore can pass through an additive tank 56 from which the ionophore is supplied to the system as needed, predetermined, calculated, etc. The addition may be continuous, batch, regular, irregular, periodic, maintenance, various intervals, etc.Alternatively or additionally, the ions may be captured, neutralized, or bound by one or more compounds of the additive in the catalyst layer, in the input stream, in the output stream, at any location in the water recirculation loop, or by a combination thereof.The system may include a sensor component configured to indicate, sense, measure, monitor, or determine a presence and / or concentration of one or more undesired ions. In other words, the sensor component may monitor how many ions have penetrated or reside in the input stream into the system, stack, device, or cell.A non-limiting example of a sensor component may be a chemosensor. The chemosensor may contain the additive with an additional indicator. The indicator may contain a fluorophore bound to a chelate receptor. A fluorophore is a fluorescent chemical compound configured to re-emit light upon light excitation. Fluorophores can absorb and emit light within a particular wavelength range referred to as absorption or excitation and emission spectra. A fluorophore thus absorbs light energy of a certain wavelength. Light absorption results in excitation of the electrons of the fluorophore. The fluorophore re-emits the absorbed light energy at another, longer wavelength when the electrons return to their unexcited ground state.The additive may therefore contain one or more chelator compounds, at least some of which contain a fluorophore bound to the chelate receptor via a spacer. The spacer may be an electron donating group, such as an amine. The electron donating group plays an important role for the sensing mechanism. The fluorophore can be designed to be inert by default, i.e., when light is directed at the fluorophore, the material does not fluoresce. This effect is known as photoinduced electron transfer (PET), in which the electron-donating group quenches the native fluorescence of the fluorophore. However, when the receptor is bound to an unwanted guest or analyte ion, such as Fe 3+, the charge interaction between the ion and the electron donating group, such as the amine, cancels the PET, thereby activating fluorescence and fluoresces the fluorophore molecule when exposed to light of a particular wavelength.The individual components of the sensor component cooperate to have a first state, a second state and a third state. The first state is a state without electron excitation of the fluorophore when the receptor of the sensor compound is not bound to an analyte ion. The second state is a state of electron excitation of the fluorophore upon absorption of light of a first wavelength by the fluorophore electrons when the receptor is bound to an analyte ion. The third state is a state of re-emission of the absorbed light energy at a second wavelength when the electrons return to their non-excited ground state. The first and second wavelengths are different from each other.A non-limiting example structure of the sensor or chemosensor component is illustrated in Figure 7. Figure 7 shows a crown ether chelator (A) with the unwanted ion (B) bound within the crown ether ring, and a spacer (C) that binds the chelate receptor to a fluorophore (D) with a binding site (E).The sensor component may contain a fluorophore-receptor moiety immobilized on a polymer surface as described herein. A non-limiting example of a fluorophore may be 1,8-naphthalimide or a derivative thereof. The receptor may be a crown ether or a derivative thereof. An advantage of the disclosed sensor mechanism is that it can be optimized for a particular ion, such as iron, with the exclusion of other ions, such as protons or hydroxides, to be present in the solution.Alternatively, the sensor component may include a measurement of the total conductivity of the inlet or outlet water to measure the total ion content. For example, a known voltage may be applied between two electrodes in the 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.The fluorophore / receptor can be immobilized on a polymer surface. The polymer may contain cellulose microparticles associated with a hydrogel such as polyhedron or polyurethane. The fluorophore-receptor molecule, cellulose, and hydrogel combination can be coated onto a support layer such as polyethylene terephthalate (PET), followed by drying and a photocrosslinking phase to solidify the hydrogel. The final fluorophore film can be made as a thin film having a thickness of about 50 μm to 50 mm. The film may contain one type of fluorophore-receptor pair or more than one type of fluorophore-receptor pair.The film may be inserted into a sensor device. The sensor device may include an LED (e.g., blue) that generates an optical excitation of the electrons in the fluorophore. The LED emission can be optically filtered to prevent damage to the film or to improve the signal-to-noise ratio. The fluorophore fluoresces when excited and emits light at a different frequency (e.g., green) relative to the concentration of ions in the solution. The emitted light may be further optically filtered to achieve a better signal-to-noise ratio or avoid confusion with the LED frequency (e.g., blue). The emitted light can be directed onto a photodiode and then digitized to determine the total ion concentration found. The sensor device may further include an electroactive polymer or an optical source to cause release of the ions from the receptors. A schematic illustration of the sensor device connected to a power source and the cell is seen in Fig. 8.The digital signal may be processed using information regarding the production of the film, the life, the aging characteristics, etc. to determine a calculated ion concentration. This may be further processed by a computing device or controller to estimate the overall state of the electrochemical device and alert the user when maintenance or replacement is recommended. The measurements may be connected to a central node or controller that processes the information of many such devices to predict the overall life of a number of devices that may be located in the same or different locations.The system, device, or cell may therefore include a sensor component including a fluorophore, a receptor, a light emitter, and a light detector. The light emitter may be configured to emit light of a certain wavelength that is absorbable by the fluorophore, such that light absorption results in excitation of the electrons of the fluorophore. The light detector may be configured to detect light energy having the specific wavelength re-emitted by the fluorophore when the electrons of the fluorophore return to their ground state. The sensor component may be configured such that the amount of light detected is related to or corresponds to the amount of analyte ion / s / s in the sensor input.The system, device, or cell may further 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 sensors described herein. The processor may be programmed to receive inputs from one or more sensors, including the chemosensors described herein. The controller may be programmed to adjust, add, or a combination thereof, a predetermined amount of the additive to the system, device, or cell in response to the received inputs. The controller may be programmed to detect a signal from the light detector and correlate the input with the amount of metal ions present in the system, in the device, in the cell, in the input stream, in the output stream, in the water recirculation circuit, or a combination thereof.A predetermined amount may be fixed or adjustable. The predetermined amount depends on the state of the system, the type of input stream, the type of cell component materials, the age of the system, and / or other conditions. The output provided by the electrical device may / may be a number and / or data associated with the analyte, its amount, or other information related to the analysis. Additionally, the controller / controllers may provide input to one or more devices, such as the light emitter, to initiate, terminate, or both light emission.Additionally or alternatively, the additive may contain a precipitant. The precipitant may be an acid configured to chemically interact, react, neutralize, or a combination thereof with the undesired ion. The acid may be a weak acid having a pH of less than 7, or about 4-6, or 4, 5, or 6. It is also contemplated that a strong acid having a pH of about 1-4 may be used. The pH of the precipitant may thus be about 1-6 or 1, 2, 3, 4, 5 or 6. Thus, the undesired ion reacts with the acidic additive to form a neutral precipitate, e.g., a harmless salt, which can be flushed out of the cell. The ions can be precipitated by the acid. The neutral precipitate should be harmless to the membrane and / or other parts of the cell.Weak acids are acids which do not completely dissociate in solution. The strength of a weak acid depends on how much it dissociates. The more it dissociates, the more strongly the acid is. The acid dissociation constant Ka is used to calculate whether an acid is a weak or strong acid. Ka is a mathematical way to express the concentration of dissociated hydrogen atoms of an acid. The smaller Ka, the weaker the acid. The weak acid may be an acid tailored to the chemistry of the undesired ion / s. For example, if the input stream contains unwanted calcium (Ca), the weak acid selected may be citric acid (C 6 H 8 O 7) which reacts with Ca to form calcium citrate Ca 3( C 6 H 5 O 7)2. Other suitable weak acids may include formic acid (HCOOH), acetic acid (CH 3 COOH), benzoic acid (C 6 H 5 COOH), hydrofluoric acid (HF), phosphoric acid (H 3 PO 4), sulphurous acid (H 2 SO 3), carbonic acid (H 2 CO 3), nitrous acid (HNO 2), hydrocyanic acid (HCN) or sulphuric acid (H2S).Strong acids, on the other hand, fully ionize in water to form hydronium ions. The concentration of H 3 O + in a strongly acidic solution is therefore equal to the initial concentration of the acid. A suitable strong acid may be sulfuric acid (H 2 SO 4), nitric acid HNO 3, or another strong acid.For the application described herein, some consideration must be given to the use of an acid. Some acids, whether strong or weak, may be corrosive and destructive to the environment of an electrochemical cell. On the other hand, the use of an acid, particularly a weak acid, may be economical due to the relative frequency and cost of weak acids.As described above and illustrated in Figure 5, the system can be connected to a maintenance cycle which automatically adds more additive at the time of periodic maintenance or prompts the user to add more cleaning additive for maintenance. The system may include a monitoring phase that monitors elements such as: the ion concentration of the current, the proportion of additive that is reacted, the number of hours the cell has been operated, the pH of the current, etc.The additive containing a (weak) acid is particularly suitable for electrolysers, in particular for membrane-based electrolysers. Electrolysers have water entry through pipes which, of course, results in the release of ions into the input stream, e.g. from the steel pipes through which the water flows. This differs, for example, from fuel cells in which the input cell does not contain liquid water, so that there are less possibilities for releasing undesired ions from the cell components into the input stream. The ions can attack the electrolyser membrane which, as already mentioned, is sensitive and which can adversely affect the longevity of the cell. In addition, the ions can attack the catalyst, which can become detached, and this leads to efficiency losses.Since contaminants can cause damage to the components such as the catalyst and the membrane of the cells, it is typical that the purest possible input source is sought. It is therefore not obvious to use ion-containing input currents. However, the purity requirement can be inconvenient, impractical and uneconomical. The additive described herein thus offers a simple way of using a variety of input streams without damaging the cell components.Moreover, although the input water stream of the electrolyser may contain purified water, other water sources such as tap water, rainwater, and even sea water may be used. Seawater may be characterized as water from a sea or ocean having a salinity of about, at least about or at most about 3.5%, or 35 g / L or ppm salt(s). The salinity 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. When the input water is seawater, the input current is even more ionic and the deionization techniques may not be 100% effective, especially as the stack ages. The addition of the additive therefore improves ion removal and may extend the life of the cell, device, stack, and / or system. The input water stream may have a neutral pH of about 7 or between 5.2 and 9.5.In at least one embodiment, component configured to capture and / or remove ions may be stationary or immobilized. Instead of an additive that may be included in an input or output stream, the compounds configured to capture, neutralize, and / or release the undesired ions may be immobilized on a surface. The surface may be a polymer surface. The surface may form a component within the cell, device, stack, or system. The surface may be a surface of a cell component such as the cathode catalyst layer, the anode catalyst layer, or a surface upstream of the cell.In a non-limiting example, the additive may include a chelator, an ionophore, or both, immobilized on a surface of an ion cleaner. The ion purifier may be located downstream of the water source, the purifier, or both and upstream of the electrolysis cell. A schematic illustration of a non-limiting example of the ion cleaner is shown in FIG. 9. The system 300 of FIG. 9 includes the input power source 52, a purifier 54, and a cell 50. upstream of the cell 50, is the ion purifier 62 containing the stationary immobilized additive configured to trap, neutralize, or chelate unwanted ions.The ion cleaner can be maintained at regular intervals. The purifier may also contain a renewal cycle to remove the chelated ions and allow the chelating of new ions. The renewal cycle may be activated chemically (e.g., by washing with a solution having a certain pH), electrochemically (e.g., by voltage), thermally, optically, by vibration (e.g., with a piezoelectric or electroactive polymer), or by a combination thereof, to remove the chelated ions.A non-limiting example of a maintenance cycle of the system containing immobilized additive is schematically illustrated in Figures 10 and 11. Figure 11 schematically shows chelator moieties 70 on support 72. During the capture of undesired ions in the cell, undesired ions 74 are bound to chelator moieties 70 on support 72. During the renewal portion of the cycle, one of the activation modes 76 is used to remove the ions 74 from the chelator moieties 70. The ions 74 may be released into a waste stream 78.Similar to the fluorophore receptor immobilized on the polymer, the chelator / receptor can also be immobilized on a polymer surface. The polymer may contain cellulose microparticles associated with a hydrogel such as polyhedron or polyurethane. The combination of receptor molecules, cellulose and hydrogel can be coated onto a support layer such as polyethylene terephthalate (PET), followed by drying and a photocrosslinking phase to solidify the hydrogel. The finished film can be made as a thin film of about 50 μm to 50 mm. The film may contain one or more types of receptor. The film may be continuous or discontinuous on one or more surfaces of the cell. For example, the film may be a continuous layer on one side of the catalyst layer, which side may be directly adjacent to the membrane.The immobilized additive may be located upstream of the cell or within the cell. The receptor may be contained, for example, in the catalyst layer(s), adjacent or immediately adjacent to the membrane. A schematic example of the receptors in the catalyst layers is shown in Figure 12. In FIG. 12, the membrane 32 is surrounded by the anode catalyst layer 34 and the cathode catalyst layer 36. Both catalyst layers 34, 36 contain receptors 80, e.g., chelator receptors 80, that are configured to capture unwanted ions 74 that can attack membrane 32 if not captured.In one or more embodiments, the system or device may include a plurality of cells. The cells may receive water from a shared reservoir. The reservoirs may be a tank, a vessel, or a basin. The incoming water stream entering the common reservoirs may have been passed through a / deionization apparatus / subsystem to remove unwanted ions. The deionization apparatus may contain the one or more of the additives described herein.A schematic illustration of the system with the common additive reservoir is shown in Figure 13. A non-limiting example system 400 illustrated in FIG. 13 includes a common water reservoir 82 containing an additive as disclosed herein that binds undesired ions from the input stream. The system 400 further includes a plurality of cells 50, which are schematically depicted herein as a single cell 50. A membrane 86 is located upstream of the plurality of cells. the membrane 86 may be a semi-permeable, selective, or selectively permeable membrane that prevents the passage of the additive +ion, such as a chelator-metal complex, into the cells 50. The membrane 86 allows water molecules to pass. A non-limiting example of a membrane may include a polymer such as polyhedron or polyurethane having a pore size of about 1-10, 2-8, or 3-7 nm.The +Ion additive from the common reservoir 82 passes via path A into a deionization reservoir 84 where the additive is regenerated at B and the clean regenerated additive passes via path C back into the common reservoir. The undesired ions are flushed out of the deionization reservoir 84 and out of the system 400. The regeneration step may be carried out chemically, thermally, electrochemically, or by another chemical method. The deionization reservoir 84 may be in the stack or at some other location.A non-limiting example of an additive may include a short chain polymer that may have the same backbone chemistry as the hydrogel membrane or other chemistry. The additive may have a molecular weight (MW) between 5 and 100, 10 and 90, or 20 and 80. A higher MW could prevent the ability of the additive to diffuse adequately. A lower MW could allow the complexed additive +Ion to move through the membrane, which is undesirable. The additive may have side chains that bind, capture, or electrochemically neutralize the ions in the solution. A non-limiting example is a crown ether that binds a particular metal ion.A method for slowing, reversing, or preventing the aging process of an electrochemical cell is disclosed herein. The method may include providing an additive to an input stream of a cell. The method may include incorporating the additive in an amount or concentration such that a threshold amount or concentration of an undesired ion / ions that cause or potentially cause cell degradation is removed. The method may include providing an additive having a pKa or dissociation constant of a suitable additive based on a pH or pH range of a cell during operation. The method may include selecting an additive that does not bind protons at a pH or in a pH range of a cell during operation based on its pKa / pKa. The method may include providing the additive in the cell, the device, or the system periodically, periodically, at periodic intervals, during maintenance testing, continuously, discontinuously, etc. The method may include adding an additive that forms a metal complex, passing the metal complex through a membrane into a regenerator, releasing unwanted ions, and recycling or recycling the remaining additive in the system. The method may include providing an additive that is a precipitant, a weak acid, a chelating agent, an ionophore, or a combination thereof.The method may further include measuring, evaluating, monitoring, detecting, or a combination thereof, an amount of analyte ion / ions using a sensor component described herein. The method may include providing a sensing component that includes a fluorophore and a receptor bound via a spacer constructed to comprise the PET such that the electron donating group of the spacer quenches the native fluorescence of the fluorophore unless the analyte ion is bound to the receptor. The method may include quenching the PET when the receptor is bound to a guest analyte ion, thereby activating fluorescence so that the fluorophore molecule fluoresces when exposed to light of a certain predetermined frequency. The method may include emitting light of a particular wavelength to excite the electrons of the fluorophore. The method may include detecting light of a particular wavelength re-emitted by the fluorophore when the electrons return to their ground state. The method may include translating, related, calculating, approximating the amount of light detected to the amount of analyte ion / ions that is / are present in the system, stack, device, and / or cell. The method may include one or more processors receiving input from one or more sensors. The method may include one or more processors that provide input to one or more devices such as the light emitter.The method may include removing an undesired ion / ions from the water circuit of the cell using the additive compound(s) immobilized on a surface. The method may include passing the input water stream over a purifier having a surface with receptors configured to trap the undesired ions. The method may include renewing the detergent by electrochemically, chemically, thermally, optically activating or activating by vibrating the separation of the ions from the additive.The method may include using multiple cells and removing undesired ions from the multiple cells. The removing may include having a single input stream that may contain undesired ions. The method may include passing the single input stream over a common container, which may be configured as a deionization basin containing the additive disclosed herein. The method may include trapping the undesired ions with the additive in the basin. The method may further include preventing the complexed additive + undesired ionic compounds from occurring downstream of the basin by providing a semi-permeable membrane that allows water molecules to be transmitted and the complexed additive + undesired ionic compounds not to be transmitted. The method may include regenerating the additive in a deionization reservoir downstream of the basin. The method may include recycling the purified additive by recycling it to the common reservoir. The method may include releasing the ions from the system.The processes, methods, or algorithms disclosed herein may be provided to or implemented by a processing device, controller, or computer, which may include any existing programmable electronic controller or dedicated electronic controller. Likewise, the processes, methods, or algorithms can be stored as data and instructions executable by a controller or computer in many forms including, but not limited to, information permanently stored on non-writable storage media such as ROM devices and information alterably stored on writeable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The processes, methods, or algorithms can also be implemented in an executable software object. Alternatively, the processes, methods, or algorithms can be embodied in whole or in part by suitable hardware components, such as Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software and firmware components.The following application is related to the present applications: U.S. Pat. Appl. Ser. Nos. _ (RBPA 0432 PUS, RBPA 0440 PUS, RBPA 0442 PUS and RBPA 0448 PUS) filed under _, which are incorporated herein by reference in their entirety.While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments may be combined to form further embodiments of the invention that may not be expressly described or depicted. While various embodiments could be described as being advantageous or preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system characteristics, which depend 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, serviceability, weight, mullability, ease of assembly, etc. As such, where embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more features, these embodiments are not outside the scope of the disclosure and may be desirable for particular applications.

Claims

An electrochemical hydrogen stack comprising: a plurality of electrochemical hydrogen cells; a common water input source upstream of the plurality of electrochemical hydrogen cells, wherein the common water input source includes a water stream including metal ions; and a deionization additive source including a deionization additive that selectively binds the metal ions and does not bind hydrogen ions.The electrochemical hydrogen stack of claim 1, wherein the water stream is a seawater stream having a salt concentration of about 15-35 mg / L.The electrochemical hydrogen stack of claim 1, further comprising a regenerating device connected to the deionization additive source.The electrochemical hydrogen stack of claim 1, further comprising a water permeable membrane impermeable to additive bound ions.The electrochemical hydrogen stack of claim 1, wherein the deionization additive is a chelating agent.The electrochemical hydrogen stack of claim 1, wherein the deionization additive has a dissociation constant value that is different from a pH of the operated electrochemical hydrogen stack.The electrochemical hydrogen stack of claim 1, further comprising an ion additive impermeable membrane, wherein both the deionization additive and the membrane contain a hydrogel.The electrochemical hydrogen stack of claim 1, wherein the electrochemical cells are electrolysers.A deionization cycle of an electrolyser stack comprising: a water source releasing a water stream containing metal ions; a deionization additive source downstream of the water stream, wherein the deionization additive removes the metal ions from the water stream by chemically bonding the metal ions upstream of an electrolyser stack; a water permeable membrane disposed between the electrolyser stack and the deionization additive source; and an additive regenerating device disposed downstream of the water permeable membrane and upstream of the water source.The electrolysis stack deionization cycle of claim 9, wherein the deionization additive is an ionophore.The electrolysis stack deionization cycle of claim 9, wherein the deionization additive is a chelating agent containing a metal ion receptor.The electrolysis stack deionization cycle of claim 9, wherein the metal ions are iron ions.The electrolysis stack deionization cycle of claim 9, wherein the water permeable membrane comprises a hydrogel.The electrolysis stack deionization cycle of claim 9, wherein the water permeable membrane and the deionization additive have a different chemical composition.The electrolysis stack deionization cycle of claim 9, wherein the water permeable membrane is impermeable to the additive.The electrolysis stack deionization cycle of claim 9, wherein the regenerating device is an electrochemical regenerating device.A deionization system of a fuel cell stack comprising: a plurality of fuel cells, each fuel cell including a membrane adjacent catalyst layers; and an immobilized deionization additive disposed in the catalyst layers, wherein the immobilized deionization additive includes a plurality of receptors that selectively bind metal ions while not binding protons, wherein the fuel cell stack has a common regeneration cycle for the plurality of fuel cells to remove bound metal ions from the fuel cell stack.The fuel cell stack deionization system of claim 17, wherein the immobilized deionization additive comprises cellulose microparticles associated with a hydrogel.The deionization system of a fuel cell stack of claim 17, wherein said metal ions contain iron ions.The deionization system of a fuel cell stack of claim 17, wherein the immobilized deionization additive is a continuous film having a thickness of about 50 μm to 50 mm.

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