Systems for lithium recovery and carbon dioxide sequestration and related methods

Abstract

Systems that can recover metal resources, such as lithium and lithium ions, and can also sequester carbon dioxide, and related methods, are generally described.

Description

[0001] SYSTEMS FOR LITHIUM RECOVERY AND CARBON DIOXIDE SEQUESTRATION AND RELATED METHODS

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63 / 623,927, filed January 23, 2024, and entitled “Systems for lithium recovery and carbon dioxide sequestration and related methods,” which is incorporated herein by reference in its entirety for all purposes.

[0004] TECHNICAL FIELD

[0005] Systems that can recover metal resources, such as metal ions, including lithium, and can also sequester carbon dioxide, and related methods, are generally described.

[0006] BACKGROUND

[0007] Changes in global climate patterns are driving a rapid transition from fuel-based cars to electric vehicles. In addition, the ever-increasing demand for renewable energy is leading to an increase in large-scale energy storage systems for stable energy supply. As a result, global demand for lithium for use in rechargeable batteries, such as lithium-ion batteries is increasing rapidly.

[0008] Lithium is typically produced from brines using the lime soda evaporation method, in which brine water containing lithium ions is evaporated, generally over the course more than a year. Sequential precipitation of contaminating salts (i.e., salts that do not include the lithium ions) is often necessary prior to the final recovery of a pure, lithium-containing product that includes the lithium ions. These sequential precipitation steps along with precipitating the lithium-containing product require the addition of large quantities of additional chemicals and can lead to an increased environmental burden. This approach also requires a large area of land and can have significant adverse effects on the surrounding environment. As production scales up to meet the growing demand for lithium, it will be difficult to for the land withstand the increasing demands and environmental footprint requirements.

[0009] Approaches to solving these challenges that do not require the addition of chemicals or occupy a large land area, would be advantageous. One approach is using electrochemical lithium recovery system to extract lithium from brines with high selectivity within a compact system. With this approach, Li+in the brine can be captured selectively from a feed solution and then released into a sweep stream to yield a high- purity Li+solution as LiOH or LiCl, with the composition of the product depending on electrodes used. However, although lithium is commercially traded as solid lithium carbonate (Li2COa), studies on related electrochemical systems have focused on separating lithium with high selectivity from lithium chloride brines and producing a lithium solution with a low concentration (due to the relatively high solubility of lithium chloride), which makes it difficult to be applied at the commercial level. Accordingly, improved systems and methods for producing lithium and other compounds is desired.

[0010] SUMMARY

[0011] Systems that can recover metal resources, such as lithium ions, and can also sequester carbon dioxide, and related methods are described. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0012] In one aspect, a system is described, the system comprising an electrochemical cell configured to capture a cation with a first applied voltage and release the cation with a second applied voltage; a capture container configured to receive a compound comprising the cation, the capture container associated with a heating element; and a conduit in fluidic communication with the capture container and configured to provide carbon dioxide to the capture container.

[0013] In another aspect, a method for producing lithium carbonate, the method comprising flowing a first stream comprising lithium cations to a capture container; flowing a second stream comprising carbon dioxide to the capture container; heating the capture container to remove at least a portion of solvent from the first stream; and precipitating lithium carbonate.

[0014] In another aspect, a method for capturing carbon dioxide, the method comprising flowing a stream comprising carbon dioxide through a conduit to a capture container comprising cations; reacting the carbon dioxide with the cations; heating the capture container to remove at least a portion of solvent from the stream; and precipitating a carbonate compound.

[0015] In another aspect, a method for capturing carbon dioxide, the method comprising: flowing a first stream comprising cations to a capture container; flowing a second stream comprising the carbon dioxide to the capture container; heating the capture container to remove at least a portion of the solvent from the first stream; reacting the carbon dioxide with the cations; precipitating a carbonate compound.

[0016] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the figures, selected embodiments are shown. These embodiments are not the only arrangements enabled and covered by this disclosure, and are provided as examples only:

[0019] FIG. 1A is a schematic illustration of one example of a system comprising an electrochemical cell, wherein the electrochemical cell comprises a mixture of cations, including a cation of interest;

[0020] FIG. IB depicts a cation of interest sequestered by a first electrode of an electrochemical cell, allowing other cations to be removed;

[0021] FIGS. 1C-1D are schematic illustrations showing the release of a cation of interest from the first electrode and flowing the cation of interest to a capture container of a system; FIG. 1 E is a schematic illustration showing the concentration of a cation of interest in a concentrating container of a system;

[0022] FIGS. 1F-1G are schematic illustrations depicting the reaction of a cation of interest with carbon dioxide to form a carbonate compound comprising the cation of interest;

[0023] FIGS. 1H-1J are schematic illustrations showing the configuration of an electrochemical cell, a capture container, a concentrating container, and conduits;

[0024] FIG. 2 is a schematic diagram showing a hybrid electrochemical-thermal process for Ei2CO3 production via mineralization of CO2 absorbed by purified lithium-ion solutions;

[0025] FIG. 3 is a schematic diagram of a carbon capture and evaporative concentration system, in which the EiOH produced in the electrochemical cell is sprayed in a cooling tower, absorbing the CO2 which flows upwards past it, and Ei2CO3 is recovered via precipitation from the bottom of the cooling tower and water retained by the flue gas is reclaimed at the top with a plume capture unit;

[0026] FIG. 4 is a plot of a pH profile of the effluent from a Bi-based electrode in an electrochemical pH swing system;

[0027] FIG. 5 shows plots of (A) pH, (B) concentration of inorganic carbon, (C) concentration of lithium, and (D) precipitation rate in a lithium carbonate precipitation step of one process;

[0028] FIG. 6 depicts plots of scrubbing efficiency, which can be defined as the percentage of CO2 removed from flue gas stream along the length of an absorber tower for sprays, where D represents relative droplet sizes, which may depend on sorbent chemistry, according to one process;

[0029] FIG. 7 shows a schematic system diagram of an evaporative absorptionprecipitation system;

[0030] FIG. 8 is a diagram of an evaporative absorption-precipitation system along with accompanying gas handling infrastructure, Ei2CO3 recovery, and safety features;

[0031] FIG. 9 shows high throughput microfluidic drop reactors for obtaining nucleation parameters utilizing AFmachine learning;

[0032] FIG. 10 shows an EiMn2O4 electrode slurry coated using doctor blade on a graphite foil current collector; and FIGS. 11A-B show performance data for systems using LiMn2O4 gathered during cyclic voltammetry and chronopotentiometry experiments.

[0033] DETAILED DESCRIPTION

[0034] The following disclosure describes a hybrid electrochemical-thermal system and method to affect lithium brine (or some other salt-containing brine, such a sodium- containing brine and / or a potassium-containing brine) for subsequent mineralization (e.g., carbonization) by carbon dioxide. The Carbon Dioxide can be from flue gas emissions, or some other source of carbon dioxide. One approach described is described based on electrochemical lithium extraction and pH modulation to produce Li2CO3. This electrochemical approach does not necessarily require large land area or the addition of chemicals, is generally easy to deploy, and avoids the formation of byproducts, or leads to the formation of byproducts in amounts comparable to or less than those generated when using existing lithium or other metal extraction techniques. In response to the increasing demand for metals such as lithium, this disclosure includes systems and methods to not only produce carbonates such as Li2COa with commercial value through a low environmental footprint and compact system, but, in one set of embodiments, also to remove and utilize carbon dioxide from the atmosphere.

[0035] Accordingly, described herein are systems and related methods for extracting and / or purifying certain resources, such as lithium, while also sequestering carbon dioxide. While the challenges of mitigating carbon dioxide production and also meeting the growing demand for metal resources (e.g., lithium ions, lithium carbonate, lithium- ion batteries) was seemingly unrelated, the Inventors have recognized that the new and inventive systems and methods described in more detail below can combine cation extraction (e.g., Li+) with carbon dioxide sequestration. The Inventors appreciated the unexpected advantages of combining lithium extraction with carbon dioxide sequestration to produce, for example, lithium carbonate as useable product, useable directly as a compound, or as precursor for other lithium or lithium carbonate-derived products.

[0036] Lithium salts and brines are described in many locations in this disclosure. Wherever this is the case, it is to be understood that other metals can be involved as well, such as potassium, sodium, calcium, magnesium, and the like. For simplicity and efficiency in description, alternate metals (and metal compounds) not be mentioned at each location, but can be used. Substituting other metals for lithium, in any system or process of this disclosure, is within the ability of those of ordinary skill in the art, without undue experimentation, aided by the overall teachings of this disclosure.

[0037] As described in more detail below, the initial purification of lithium brines can be achieved by selective intercalation of Li+into, for example, a metal oxide electrode under an applied voltage. The captured lithium ions can then be released to generate a pure Li+ion solution upon a voltage polarity swing and / or with a simultaneous increase in pH. The enriched alkaline brine is may then be subjected to thermal treatment for further concentration, for example by evaporation, with simultaneous absorption of CO2 from flue gas emissions (and / or directly from the ambient air). The absorption of CO2 drives the precipitation of Li2COa from the brine. In some cases, the method is fully integrated to allow for both the efficient recovery of lithium (e.g., lithium ions, lithium carbonate) as a pure product while also capturing and / or mineralizing carbon dioxide. Advantageously, the integrated method can promote CO2 reduction while also generating a useful product like lithium carbonate (or some other useful mineral).

[0038] To illustrate (but not to limit), a system for lithium ion recovery and CO2 sequestration may include an electrochemical cell (e.g., two or more electrodes within a lithium brine) to capture lithium ions, and / or some other cations, when a first voltage is applied and to release (at least some of) those same captured lithium ions (or some other captured cations) when a second voltage applied. The lithium ions (or some other cations) may be released into a solution (e.g., an aqueous solution) within a concentrating container and / or capture container configured to receive a compound including the lithium cations (e.g., lithium carbonate) or some other compounds containing some other cations. The concentrating container may include some component configured to increase the concentration of the cations in the solution (e.g. an electrolyzer, a heating element). The system may include a capture container configured to receive the concentrated solution from the concentrating container and / or the compound (containing lithium cations and / or some other cations) from the electrochemical cell. The system may also include a conduit, or some other channel, for providing carbon dioxide to the container (or some other portion of the system). The system allows lithium ions (or some other cations) to be captured and converted into a useful product (e.g., lithium carbonate) while simultaneously reducing carbon dioxide from an environment, such as from the air or ambient atmosphere. Advantageously, such a system can both generate useful carbonate compounds while concomitantly reducing the amount of carbon dioxide in an environment. Related methods that may provide these advantages are also described in more detail below.

[0039] Turning to the figures, specific non-limiting embodiments are described in further detail. It should be understood that the various systems, components, features, and methods described relative to these embodiments may be used either individually and / or in any desired combination as the disclosure is not limited to only the specific embodiments described herein.

[0040] In FIG. 1A, a schematic illustration of a system 100 is shown, which includes an electrochemical cell 110. Inside the electrochemical cell 110 is a pair of electrodes, a first electrode 112 and a second electrode 114. The first electrode 112 and the second electrode 114 can be electrically coupled to a potentiostat or a power source (not shown) to provide a voltage to each electrode (e.g., a first applied voltage, a second applied voltage). The electrochemical cell 110 also contains a mixture of cations, including a cation of interest 120 and other cations 122. The cation of interest 120 is the cation an operator desires to separate from the other cations 122. Note that charge-balancing anions are omitted from the figure for clarity.

[0041] Upon the application of a first applied voltage to the first electrode, the cation of interest can move to the first electrode. For example, as shown schematically in FIG. 1A, the cation of interest 120 moves to the first electrode 112 upon the application of a first applied voltage. The first electrode 112 is not selective for the other cations 122, which may advantageously allow the cation of interest 120 to be separated from other cations 122 as those cations can be removed from the system so that only the cation of interest 122 remains within the electrochemical cell 110. For example, FIG. IB schematically depicts the electrochemical cell 110 after the cation of interest 120 has moved to the first electrode 112 and the other cations 122 have been removed from the cell. Again, note that corresponding charge-balancing anions have been omitted for clarity. Suitable electrodes, current collectors, circuitry, cells, contains, conduits, fluids, controls, and the like, at any scale (small or very large) can easily be selected by those of ordinary skill in the art with the benefit of this disclosure.

[0042] After removing other cations from the electrochemical cell, the cation of interest can be released back into the electrochemical cell (or some other portion of the system). For example, as shown schematically in FIG. 1C, the cation of interest 120 migrates from the first electrode 112. This can be achieved by applying a different applied voltage (e.g., a second voltage) to the first electrode 112 and / or the second electrode 114. The different applied voltage may have an opposite polarity than the first applied voltage used to capture the cation of interest 120. The released cation of interest 120 can then be removed from the electrochemical cell 110 and transported to a different part of the system, a capture container (e.g., via a first conduit 130, a second conduit 154), as depicted schematically in FIG. ID. The released cation of interest 120 can be flowed via the first conduit 130 to the capture container 132 as shown in FIG. IF and / or via the second conduit 154 to a concentrating container 150, as shown schematically in FIG. IE. The first conduit 130 and the second conduit 154 are both shown in FIG. ID for illustrative purposes; however, it should be understood that in some embodiments, only one of these types of conduits (either a first conduit 130 to the capture container 132 or the second conduit 154 to the capture container 150) may be present. In some embodiments, both the first conduit 130 and the second conduit 154 are present. In some embodiments, more than two conduits are present.

[0043] In some embodiments, the system 100 may comprise a concentrating container 150, which may be configured to receive the cation of interest from the electrochemical cell 110 (not shown in FIG. IE) via the second conduit 154. In some embodiments, the concentrating container comprises a solution comprising the cation of interest. In the concentrating container, the solution may be subjected to some process which results in the increased concentration of the cation of interest 120. For example, the concentrating container 150 may contain a concentrating element 152 (e.g. a heater, an electrolyzer), which may be configured to increase the concentration of the cation of interest 120 in the solution. In some embodiments, the concentrating container of the system 150 may comprise a third conduit 136 connected to the capture container of the system 132, as shown in FIG. IF.

[0044] In some embodiments, the system 100 comprises a capture container 132. In the capture container, the cation of interest can interact with carbon dioxide. By way of illustration, FIG. IF depicts a capture container of the system 132 connected to the electrochemical cell 110 via the first conduit 130 (not shown in FIG. IF) and connected to the concentrating container of the system 150 (not shown in FIG. IF) via the third conduit 136, each of which flows the cation of interest 120 to the capture container 132. FIG. IF shows the capture container 132 connected to both the electrochemical cell 110 via first conduit 130 and to the concentrating container via the third conduit 136. However, it should be understood that in some embodiments, the capture container 132 may be connected to the electrochemical cell 110 via first conduit 130 and not to the concentrating container 150 via second conduit 136, or vice versa. In some embodiments, the capture container 132 may be connected to other containers and / or processing units via other conduits.

[0045] Inside the capture container 132, the cation of interest can interact (e.g., react) with carbon dioxide. Carbon dioxide can be provided to the capture container 132 via a conduit (e.g., a fourth conduit 134). For example, as shown in FIG. IF, carbon dioxide 140 is provided to the capture container 132 via the fourth conduit 134, where it can interact with the cation of interest 120.

[0046] When the cation of interest interacts with carbon dioxide, it may directly or indirectly form a carbonate compound comprising the cation of interest. For example, shown schematically in FIG. 1G, the cation of interest 120 has formed a carbonate compound 142 that contains the cation of interest 120 (not shown in FIG. 1G). As described in more detail elsewhere herein, the carbonate compound 142 may be relatively insoluble relative to the solvent and may precipitate out of solution (and subsequently recovered from the solution).

[0047] The concentrating container, capture container, conduits, and electrochemical cell as described above a may be arranged in any of a variety of suitable configurations. For example, FIG. 1H shows a configuration of the system 100 in which the electrochemical cell 110 is connected to the capture container 132 via first conduit 130 and to the concentrating container 150 via the second conduit 154, and in which the concentrating container 150 is connected to the capture container 132 via the third conduit 136. In such an embodiment, a first portion of the cation of interest generated in the electrochemical cell 110 may be flowed to the capture container 132, and a second portion of the cation of interest generated in the electrochemical cell 110 may be flowed to the concentrating container 150.

[0048] However, as described above, other embodiments of system 100 may have other configurations. For example, as shown in FIG. II, there may be configurations of the system in which the electrochemical cell is not directly connected to the capture container 132. In such embodiments, the electrochemical cell 110 is connected to the concentrating container 150 via the conduit 154, the concentrating container 150 is connected to the capture container 132 via the conduit 136, and the capture container 132 receives a stream comprising carbon dioxide via the conduit 134. Alternatively, in some embodiments as shown in FIG. 1 J, the system may not have a concentrating container 150. In such embodiments, the electrochemical cell 100 may be connected to the capture container 132 via the conduit 130 and receive a stream comprising carbon dioxide via the conduit 134. In this and other embodiments, the capture container 132 may comprise and / or be associated with a heating element and / or some concentrating element (not shown in FIG. 1 J).

[0049] Many of the embodiments described herein are described in the context of extracting lithium ions from a source of lithium ions (e.g., from a lithium brine) while also capturing carbon dioxide to form a carbonate (e.g., lithium carbonate). However, it should be understood that other cations may be isolated and reacted with carbon dioxide. For example, in some embodiments, the cation comprises an alkali metal cation (e.g., sodium, potassium, lithium, rubidium, and / or cesium). In some embodiments, the cation comprises an alkaline earth metal (e.g. magnesium, calcium, strontium). Other cations are also possible.

[0050] In some embodiments, cations (e.g., Li+) are captured from and / or released into a solution comprising the cations and a solvent. For various such embodiments, the solvent of the solution is water (e.g., the solution is an aqueous solution). That is to say, in some embodiments, the various streams (e.g., a first stream, a second stream) described herein comprise water, and the cations may be dissolved in the water. When the cations to be extracted are lithium cations, this has the added advantage of improving the recovery of the resulting carbonate product (e.g., lithium carbonate) due, at least in part, to the lower solubility of lithium carbonate relative to other alkali metal carbonates (e.g., sodium carbonate, potassium carbonate). However, it will be understood that, for other embodiments, a different solvent and / or a mixture of solvents may be used, and such solvents and / or mixtures of solvents may have properties making them advantageous for the precipitation of other carbonate compounds. For example, in some embodiments, an appropriate solvent may be a solvent in which carbon dioxide is highly soluble and the carbonate product (e.g. lithium carbonate) is not highly soluble. In some embodiments, the solvent may be a non-aqueous solvent. For example, in some embodiments, the solvent may be polypropylene carbonate. Other solvents are also possible, as this disclosure is not so limited.

[0051] Cations may be captured from a variety of solutions. For various embodiments, cations are captured from a brine solution or mixture comprising water and an excess of salts (e.g., LiCl, NaCl). The brine solution may comprise a variety of cations. Nonlimiting examples of cations include Li+, Na+, K+, Mg2+, and / or Ca2+. In some embodiments, the brine solution may comprise one cation. In other embodiments, the brine solution may comprise a mixture of two or more cations. In certain embodiments, or more of these cations may be captured selectively over other cations in the mixture. The solution may also contain corresponding counterions (i.e., anions) for charge balancing. Non-limiting examples of anions include CT, Br", SO42', OH", and / or CO32’. In some embodiments, the brine solution may comprise one anion. In some embodiments, the brine solution may comprise a mixture of two or more anions. Other ions are possible are this disclosure is not so limited.

[0052] A brine solution may have any of a variety of suitable concentrations of cations. For example, in some embodiments, the brine solution may have a concentration of cations that is greater than or equal to 10 mmol / L, greater than or equal to 50 mmol / L, greater than or equal to 100 mmol / L, greater than or equal to 150 mmol / L, greater than or equal to 200 mmol / L, greater than or equal to 250 mmol / L, greater than or equal to 300 mmol / L, greater than or equal to 350 mmol / L, or greater than or equal to 400 mmol / L. In some embodiments, the brine solution may have a concentration of cations that is less than or equal to 450 mmol / L, less than or equal to 400 mmol / L, less than or equal to 350 mmol / L, less than or equal to 300 mmol / L, less than or equal to 250 mmol / L, less than or equal to 200 mmol / L, less than or equal to 150 mmol / L, less than or equal to 100 mmol / L, or less than or equal to 50 mmol / L. Combinations of these ranges are also possible (e.g. the brine solution may have a concentration of cations that is greater than or equal to 10 mmol / L and less than or equal to 450 mmol / L, greater than or equal to 50 mmol / L and less than or equal to 400 mmol / L, or greater than or equal to 100 mmol / L and less than or equal to 350 mmol / L). Other ranges are also possible.

[0053] To extract and / or release cations from and / or into solution, one or more ion-selective electrodes may be used in an electrochemical cell. In some embodiments, for example, the system comprises an electrochemical cell, including a first electrode that is selective for the desired cations (e.g., Li+) over other cations. In some embodiments, the system comprises an electrochemical cell including a second electrode that is selective for other desired cations (e.g., H+) over other (undesired) cations. In some such embodiments, the selection for one type of cation (e.g., H+) by the second electrode may result in release of other types of cations by the first electrode (e.g., Li+). By way of illustration and not limitation, in an embodiment where the first electrode captures lithium ions, the second electrode may capture hydrogen ions, which can result in the release of lithium ions by the first electrode back into the solution. This can be done such that the first electrode captures lithium ions, undesired cations are removed from the system (e.g. washed away from the electrochemical cell), and then the second electrode captures hydrogen ions, resulting in the pH of the solution changing (i.e., making the solution less acidic) with lithium ions returned to the solution after the undesired cations have been removed. In some embodiments, the electrode that captures the cation may also release the cation (e.g., after applying an opposite polarity to the electrode). In some embodiments, a single electrode may both capture cations (e.g., a first voltage) and subsequently release cations (e.g., a second voltage).

[0054] A variety of electrodes may be suitable to capture and / or release a particular cation (e.g., Li+). In some embodiments, the first electrode may capture (and / or release) cations (e.g., lithium ions). In some embodiments, the first electrode comprises a manganese oxide compound and / or an iron phosphate compound. In some embodiments, the first electrode comprises a manganese oxide having a particular crystal structure; for example, in some embodiments, the first electrode comprises k-MnCh. In some embodiments, the first electrode comprises lithium iron phosphate. In some embodiments, the first electrode comprises a mixed metal oxide. For example, in some embodiments, the first electrode comprises a lithium nickel manganese cobalt oxide.

[0055] In some embodiments, the second electrode capture (and / or release) H+ions. In some embodiments, the second electrode may comprise a bismuth compound. In some embodiments, the second electrode may comprise platinum, carbon, and / or iridium oxide. In some embodiments, the second electrode may be configured to capture (and / or release) cations which are not H+ions. For example, in some embodiments, the second electrode may comprise silver chloride. However, the first electrode and / or the second electrode may be configured to capture / and or release any of a variety of other suitable ions. Of course, other electrodes are possible as this disclosure is not so limiting. The first electrode and / or second electrode may be selected according to a variety of appropriate criteria, including selectivity for the cation of interest, electrode capacity, and / or stability at broad range of pH values.

[0056] Electrodes may be fabricated using any of a variety of suitable procedures. For example, in some embodiments, an electrode may be fabricated by spray coating, pressing, and / or dip coating. In some embodiments, an electrode may be fabricated using ink casting (e.g. casting an in which comprises the electrode material to form an electrode).

[0057] Any of a number of possible processes may be used to select a first electrode and / or second electrode. For example, in some embodiments, one may perform cyclic potentiometry using a first and / or second electrode of interest in a solution comprising the cation of interest in order to determine the electric potential of the reactions carried out at the first and / or second electrode. In some embodiments, an electrode may be selected which minimizes the electric potential of the reactions carried out at the first and / or second electrode. In some embodiments, an electrode may be selected which minimizes the electric potential of the reactions carried out at the first and / or second electrode while maintaining a high current density. One may also measure the pH and / or ion concentration of the solution resulting from those reactions. In some embodiments, the current efficiency of the electrode may be determined by assessing the change in the pH of the solution resulting from a reaction and comparing the pH change to the current. This may provide a measure of current efficiency. For example, in some embodiments, perfect current efficiency would be achieved if, for every electron transferred, one H+ion was captured or released at the corresponding electrode. In some embodiments, an electrode may be chosen which maximizes current efficiency. In some embodiments, the first electrode and / or the second electrode may have any of a variety of suitable structural features. For example, in some embodiments, the first electrode and / or the second electrode may advantageously have a high porosity and / or a high surface area. In some embodiments, the first electrode and / or second electrode may be an interdigitated electrode. In some embodiments, an interdigitated electrode may comprise a conductive base layer and an electrochemically active layer. In some embodiments, the conductive base layer may comprise conductive particles such as silver nanoparticles and / or carbon nanotubes. In some embodiments, the electrochemically active layer may comprise a manganese oxide compound and / or an iron phosphate compound. In some embodiments, interdigitated electrodes may offer several advantages over other electrode structures. For example, interdigitated electrodes may reduce inter-electrode distances. Without wishing to be bound by any particular theory, it is believed that reduced inter-electrode distances may overcome possible ion transport and electrical resistances by increasing the electrolyte volume / electrode material ratio. In some embodiments, interdigitated electrodes may have small length scales. Without wishing to be bound by any particular theory, it is believed that the smaller length scales of the interdigitated electrodes may improve mass transport of ions.

[0058] An interdigitated electrode may have any of a variety of suitable feature sizes. For example, in some embodiments, the interdigitated electrode may comprise features with a size of greater than or equal to 0.1 mm, greater than or equal to 0.25 mm, greater than or equal to 0.5 mm, greater than or equal to 0.75 mm, greater than or equal to 1 mm, greater than or equal to 1.25 mm, greater than or equal to 1.5 mm, or greater than or equal to 1.75 mm. In some embodiments, an interdigitated electrode may comprise features having a size of less than or equal to 2 mm, less than or equal to 1.75 mm, less than or equal to 1.5 mm, less than or equal to 1.25 mm, less than or equal to 1 mm, less than or equal to 0.75 mm, less than or equal to 0.5 mm, or less than or equal to 0.25 mm. Combinations of these ranges are also possible (e.g., in some embodiments, an interdigitated electrode may comprise features having a size of greater than or equal to 0.1 mm and less than or equal to 2 mm, greater than or equal to 0.25 mm and less than or equal to 1.75 mm, or greater than or equal to 0.5 mm and less than or equal to 1.5 mm). Other ranges are also possible.

[0059] In some embodiments, interdigitated electrodes may be fabricated using either screen-printing and / or inkjet printing. These methods may offer several advantages, such as low cost, high feature resolution, high precision, and processing flexibility. In some embodiments, inkjet printing may produce interdigitated electrodes with feature sizes greater than or equal to approximately 0.1 mm, and screen-printing may produce interdigitated electrodes with feature sizes greater than or equal to 0.5 mm.

[0060] In some embodiments, a first voltage is applied to an electrode (e.g., a first electrode). In some embodiments, the first applied voltage is greater than or equal to 0.1 V, greater than or equal to 0.5 V, greater than or equal to 1.0 V, greater than or equal to 1.3 V, greater than or equal 1.5 V, greater than or equal 1.7 V, greater than or equal to

[0061] 2.0 V, greater than or equal 2.4 V, greater than or equal to 3.0 V, greater than or equal to

[0062] 3.2 V, greater than or equal to 3.6 V, greater than or equal to 4.0 V, or greater than or equal to 4.4 V (e.g., relative to a reference electrode). In some embodiments, the first applied voltage is less than or equal to 4.4 V, less than or equal to 4.0 V, less than or equal to 3.6 V, less than or equal to 3.2 V, less than or equal to 3.0 V, less than or equal to 2.4 V, less than or equal to 2.0 V, less than or equal to 1.7 V, less than or equal to 1.5 V, less than or equal to 1.3 V, less than or equal to 1.0 V, less than or equal to 0.5 V, or less than or equal to 0.1 V (e.g., relative to a reference electrode). Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 0.1 V and less than or equal to 4.4 V). Other ranges are possible.

[0063] In some embodiments, a second voltage is applied to an electrode (e.g., a second electrode). In some such embodiments, the second electrode may have a polarity opposite the first electrode. In some embodiments, the second applied voltage is greater than or equal to 0.1 V, greater than or equal to 0.5 V, greater than or equal to 1.0 V, greater than or equal to 1.3 V, greater than or equal 1.5 V, greater than or equal 1.7 V, greater than or equal to 2.0 V, greater than or equal 2.4 V, greater than or equal to 3.0 V, greater than or equal to 3.2 V, greater than or equal to 3.6 V, greater than or equal to 4.0 V, or greater than or equal to 4.4 V (e.g., relative to a reference electrode). In some embodiments, the second applied voltage is less than or equal to 4.4 V, less than or equal to 4.0 V, less than or equal to 3.6 V, less than or equal to 3.2 V, less than or equal to 3.0 V, less than or equal to 2.4 V, less than or equal to 2.0 V, less than or equal to 1.7 V, less than or equal to 1.5 V, less than or equal to 1.3 V, less than or equal to 1.0 V, less than or equal to 0.5 V, or less than or equal to 0.1 V (e.g., relative to a reference electrode). Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 0.1 V and less than or equal to 4.4 V). Other ranges are possible.

[0064] In some embodiments, the capture and / or release steps performed in the electrochemical cell may produce a stream comprising the cation of interest. In some embodiments, the stream comprising the cation of interest may be an output from the electrochemical cell.

[0065] In some embodiments, the capture and / or release steps performed in the electrochemical cell may produce a solution comprising the cation of interest (e.g. an aqueous solution comprising Li+ions). This solution may have any of a variety of suitable concentrations of the cation of interest. In some embodiments, the solution may have a concentration of the cation of interest of greater than or equal to 0.01 M, greater than or equal to 0.025 M, greater than or equal to 0.05 M, greater than or equal to 0.075 M, greater than or equal to 0.1 M, greater than or equal to 0.125 M, greater than or equal to 0.15 M, greater than or equal to 0.175 M, greater than or equal to 0.2 M, greater than or equal to 0.225 M, greater than or equal to 0.25 M, and / or greater than or equal to 0.275 M. In some embodiments, the solution may have a concentration of the cation of interest of less than or equal to 0.3 M, less than or equal to 0.275 M, less than or equal to 0.25 M, less than or equal to 0.225 M, less than or equal to 0.2 M, less than or equal 0.175 M, less than or equal to less than or equal to 0.15 M, less than or equal to 0.125 M, less than or equal to 0.1 M, less than or equal to 0.075 M, less than or equal to 0.05 M, or less than or equal to 0.025 M. Combinations of these ranges are also possible (e.g. the solution may have a concentration of the cation of interest of greater than or equal to 0.01 M and less than or equal to 0.3 M, greater than or equal to 0.025 M and less than or equal to 0.275 M, or greater than or equal to 0.05 M and less than or equal to 0.25 M). Other ranges are also possible. In some embodiments, an output from the electrochemical cell may comprise the solution comprising the cation of interest.

[0066] Various embodiments of the system include one or more containers. The one or more containers may comprise a solution containing cations (e.g., lithium cations), such as a lithium brine (i.e., an aqueous solution comprising lithium salts). Many containers are suitable. As the system operates, the solution may experience a pH swing (e.g., from acidic to basic, from basic to acidic, from pH 4 to pH 9, from pH 10 to pH 6), so the capture container should be able to withstand both acidic and basic conditions at the various pHs the system can achieve. In some embodiments, the capture container is configured to withstand a pH of less than or equal to 10, less than or equal to 8, less than or equal to 7, less than or equal to 6, less than or equal to 4, less than or equal to 2, or less than or equal to 0. In some embodiments, the capture container is configured to withstand a pH of greater than or equal to 0, greater than or equal to 2, greater than or equal to 4, greater than or equal to 6, greater than or equal to 7, greater than or equal to 8, or greater than or equal to 10. Combinations of the foregoing ranges are also possible (e.g., greater than or equal to 0 and less than or equal to 10). Other ranges are possible as this disclosure is not so limiting.

[0067] In some embodiments, the system may comprise a concentrating container. In some embodiments, the concentrating container may comprise a solution containing cations (e.g. lithium cations), such as a lithium brine. In some embodiments, a stream comprising a cation of interest (e.g. lithium cations) and / or some other cations may be flowed to the concentrating container. In some embodiments, at least a portion of the stream from the electrochemical cell comprising cations may be flowed into the concentrating container.

[0068] In certain embodiments, the concentrating container comprises a concentrating element configured (e.g. an electrolyzer, a heating element). In some embodiments, a process may be performed on the solution comprising cations within the concentrating container that causes an increase in the concentration of cations in the solution. In some embodiments, the process may comprise evaporating some of the solvent of the solution and / or electrolysis. In some embodiments, the concentrating element may comprise a heating element. Non-limiting examples of heating elements include resistive heaters, ceramic heaters, and / or liquid heaters.

[0069] In some embodiments, the solution in the concentrating container may be heated to a temperature of greater than or equal to 50 °C, greater than or equal to 55 °C, greater than or equal to 60 °C, greater than or equal to 65 °C, greater than or equal to 70 °C, greater than or equal to 75 °C, greater than or equal to 80 °C, greater than or equal to 85 °C, greater than or equal to 90 °C, or greater than or equal to 95 °C. In some embodiments, the solution in the concentrating container may be heated to a temperature of less than or equal to 100 °C, less than or equal to 95 °C, less than or equal to 90 °C, less than or equal to 85 °C, less than or equal to 80 °C, less than or equal to 75 °C, less than or equal to 70 °C, less than or equal to 65 °C, less than or equal to 60 °C, or less than or equal to 55 °C. Combinations of these ranges are also possible (e.g. in some embodiments the solution in the concentrating container may be heated to a temperature of greater than or equal to 50 °C and less than or equal to 100 °C, greater than or equal to 55 °C and less than or equal to 95 °C, or greater than or equal to 60 °C and less than or equal to 90 °C). Other ranges are also possible. In such embodiments, the concentrating container may comprise an additional conduit for the elimination of the vaporized solvent.

[0070] In some embodiments, the concentrating container may comprise an electrolyzer. In some embodiments, the electrolyzer may be configured to withstand a relatively high pH. For example, in some embodiments, the electrolyzer may be configured to withstand a pH of greater than or equal to 7, greater than or equal to 8, greater than or equal to 9, greater than or equal to 10, greater than or equal to 11, greater than or equal to 12, or greater than or equal to 13. In some embodiments, the electrolyzer may be configured to withstand a pH of less than or equal to 14, less than or equal to 13, less than or equal to 12, less than or equal to 11, less than or equal to 10, less than or equal to 9, or less than or equal to 8. Combinations of these ranges are also possible (e.g. in some embodiments, the electrolyzer may be configured to withstand a pH of greater than or equal to 7 and less than or equal to 14, greater than or equal to 8 and less than or equal to 13, and / or greater than or equal to 9 and less than or equal to 12). Other ranges are also possible.

[0071] In some embodiments, the electrolyzer may have any of a variety of suitable electrode surface areas. For example, in some embodiments, the electrolyzer may have an electrode surface area of greater than or equal to 1 m2, greater than or equal to 5 m2, greater than or equal to 10 m2, greater than or equal to 20 m2, greater than or equal to 50 m2, greater than or equal to 100 m2, greater than or equal to 120 m2, greater than or equal to 150 m2, greater than or equal to 200 m2, or greater than or equal to 220 m2. In some embodiments, the electrolyzer may have an electrode surface area of less than or equal to 250 m2, less than or equal to 220 m2, less than or equal to 200 m2, less than or equal to 150 m2, less than or equal to 120 m2, less than or equal to 100 m2, less than or equal to 50 m2, or less than or equal to 5 m2. Combinations of these ranges are also possible (for example, in some embodiments, the electrolyzer may have an electrode surface area of greater than or equal to 1 m2and less than or equal to 250 m2, greater than or equal to 5 m2and less than or equal to 220 m2, or greater than or equal to 10 m2and less than or equal to 200 m2). Other ranges are also possible.

[0072] In some embodiments, the electrolyzer may have any of a variety of suitable current densities. For example, in some embodiments, the electrolyzer may have a current density of greater than or equal to 0.05 mA / cm2, greater than or equal to 0.1 mA / cm2, greater than or equal to 0.25 mA / cm2, greater than or equal to 0.5 mA / cm2, greater than or equal to 0.75 mA / cm2, greater than or equal to 1 mA / cm2, or greater than or equal to 1.25 mA / cm2. In some embodiments, the electrolyzer may have a current density of less than or equal to 1.5 mA / cm2, less than or equal to 1.25 mA / cm2, less than or equal to 1 mA / cm2, less than or equal to 0.75 mA / cm2, less than or equal to 0.5 mA / cm2, less than or equal to 0.25 mA / cm2, or less than or equal to 0.1 mA / cm2. Combinations of these ranges are also possible (e.g. in some embodiments, the electrolyzer may have a current density of greater than or equal to 0.05 mA / cm2and less than or equal to 1.5 mA / cm2, greater than or equal to 0.1 mA / cm2and less than or equal to 1.25 mA / cm2, or greater than or equal to 0.25 mA / cm2and less than or equal to 1 mA / cm2). Other ranges are also possible. In some embodiments, the current density and / or electrode surface area of the electrolyzer may be chosen in order to achieve a desired production rate of a final product.

[0073] In some embodiments, the concentrating container of the system may output a concentrated solution comprising the cation of interest. In some embodiments, the concentrated solution may have a concentration of the cation of interest of greater than or equal to 0.5 M, greater than or equal to 1 M, greater than or equal to 1.5 M, greater than or equal to 2 M, greater than or equal to 2.5 M, greater than or equal to 3 M, or greater than or equal to 3.5 M. In some embodiments, the concentrated solution may have a concentration of the cation of interest of less than or equal to 4 M, less than or equal to 3.5 M, less than or equal to 3 M, less than or equal to 2.5 M, less than or equal to 2 M, less than or equal to 1.5 M, or less than or equal to 1 M. Combinations of these ranges are also possible (e.g. the concentrated solution may have a concentration of the cation of interest of greater than or equal to 0.5 M and less than or equal to 4 M, greater than or equal to 1 M and less than or equal to 3.5 M, or greater than or equal to 1.5 M and less than or equal to 3 M). Other ranges are also possible.

[0074] In some embodiments, the system may comprise a capture container. In some embodiments, the capture container may comprise a solution comprising cations (e.g. lithium ions). In some embodiments, a portion of the stream from the electrochemical cell comprising lithium cations may be flowed from the electrochemical cell to the capture container. In some embodiments, a second stream comprising lithium cations (and / or some other cations) may be flowed from the concentrating container to the capture container. In some embodiments, a third stream comprising carbon dioxide is flowed to the container. In some such embodiments, the capture container can withstand the pH of the first stream and the second stream (i.e., of different pHs).

[0075] As described in more detail below, the container may also be used to contain a solution (e.g., lithium brine) comprising cations and a solvent while also evaporating some of the solvent of the solution. Accordingly, in some embodiments, heating is applied to the capture container to remove at least a portion of the solvent. Accordingly, in some embodiments, the capture container can withstand heating to promote evaporation of the solvent. Heating can be provided in a variety of ways by a variety of techniques known to those skilled in the art. For example, heating may be provided by a heating element. Non-limiting examples of heating elements include resistive heaters, ceramic heaters, and / or liquid heaters.

[0076] In some embodiments, the system may be heated by an exhaust gas stream, In some embodiments, the exhaust gas stream may have a temperature of greater than or equal to 250 °C, greater than or equal to 275 °C, greater than or equal to 300 °C, greater than or equal to 325 °C , greater than or equal to 350 °C, greater than or equal to 375 °C, greater than or equal to 400 °C, greater than or equal to 425 °C, greater than or equal to 450 °C, or greater than or equal to 475 °C. In some embodiments, the exhaust gas stream may have a temperature of less than or equal to 500 °C, less than or equal to 475 °C, less than or equal to 450 °C, less than or equal to 425 °C, less than or equal to

[0077] 400 °C, less than or equal to 375 °C, less than or equal to 350 °C, less than or equal to

[0078] 325 °C, less than or equal to 300 °C, or less than or equal to 275 °C. Combinations of these ranges are also possible (e.g. the exhaust gas stream may have a temperature of greater than or equal to 250 °C and less than or equal to 500 °C, greater than or equal to 275 °C and less than or equal to 475 °C, or greater than or equal to 300 °C and less than or equal to 450 °C). Other ranges are also possible.

[0079] The system may also include one or more conduits for conveying a stream (e.g., a first stream, a second stream) within various portions of the system. Various appropriate conduits such a metal pipes, tubing (e.g., PVDF tubing), and the like are known to those skilled in the art.

[0080] In some embodiments, a conduit will be able to withstand the pHs of the various streams that flow within the conduit. In some such embodiments, the conduit can withstand the pH of the first stream and the second stream (i.e., of different pHs). In some embodiments, the conduit is configured to withstand a pH of less than or equal to 10, less than or equal to 8, less than or equal to 7, less than or equal to 6, less than or equal to 4, less than or equal to 2, or less than or equal to 0. In some embodiments, the conduit is configured to withstand a pH of greater than or equal to 0, greater than or equal to 2, greater than or equal to 4, greater than or equal to 6, greater than or equal to 7, greater than or equal to 8, or greater than or equal to 10. Combinations of the foregoing ranges are also possible (e.g., greater than or equal to 0 and less than or equal to 10). Other ranges are possible as this disclosure is not so limited. As mentioned elsewhere herein, a stream comprising carbon dioxide can be flowed to a capture container and may react with a component of the container. For example, some embodiments include flowing a stream comprising carbon dioxide through a conduit to a capture container comprising cations (e.g., Li+). The carbon dioxide may come from a variety of sources, such as the air or the ambient atmosphere. In some embodiments, a stream comprising carbon dioxide is from a power plant and / or from a flue, which can mitigate the carbon dioxide released from the power plant. Other sources of carbon dioxide are possible as this disclosure is not so limited.

[0081] In some embodiments, carbon dioxide reacts with a cation, or a related component of the cation (e.g., LiOH), to form a carbonate compound. In some such embodiments, the solubility of the carbonate compound may be less than that of cationic species prior to the formation of the carbonate. That is, in some embodiments, the solubility of the resulting carbonate compound may be less than those of any cationic salts of a stream or solution (e.g., lithium salts) prior to exposing the stream or solution to carbon dioxide, the capture container

[0082] In some embodiments, the capture container may have any of a variety of configurations which facilitate the reaction of carbon dioxide with the cation. For example, the capture container may be configured to maximize the contact area between the stream comprising carbon dioxide and the solution containing the cation of interest. In some embodiments, the stream comprising carbon dioxide may comprise a gas stream. In such embodiments, the capture container may comprise a gas-liquid contactor. For example, in some embodiments, the capture container may comprise a spray tower and / or a bubble column (e.g. a countercurrent bubble column reactor). Other configurations are also possible.

[0083] In some embodiments, a carbonate compound is precipitated, for example, after exposing a stream comprising cations (e.g., a first stream, a second stream) to another stream (e.g., a third stream) comprising carbon dioxide. In some such embodiments, the carbonate compound may be isolated from the capture container. Any of a variety of suitable processes and / or processing units may be used to isolate the carbonate compound from the capture container. For example, in some embodiments, the carbonate compound may precipitate out of the solution. In such embodiments, the capture container may comprise a settling tank. In such embodiments, particles of the carbonate compound may be a allowed to settle out of the solution and removed from the settling tank as solid particles.

[0084] In some embodiments, a filter may be used to separate solid carbonate particles from the solution. The filter may have any of a variety of suitable pore sizes. For example, in some embodiments, the filter may have a pore size of greater than or equal to 0.1 micron, greater than or equal to 0.2 micron, greater than or equal to 0.3 micron, greater than or equal to 0.4 micron, greater than or equal to 0.5 micron, greater than or equal to 0.6 micron, greater than or equal to 0.7 micron, greater than or equal to 0.8 micron, greater than or equal to 0.9 micron, greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 3 microns, or greater than or equal to

[0085] 4 microns. In some embodiments, the filter may have a pore size of less than or equal to

[0086] 5 microns, less than or equal to 4 microns, less than or equal to 3 microns, less than or equal to 2 microns, less than or equal to 1 micron, less than or equal to 0.9 micron, less than or equal to 0.8 micron, less than or equal to 0.7 micron, less than or equal to 0.6 micron, less than or equal to 0.5 micron, less than or equal to 0.4 micron, less than or equal to 0.3 micron, less than or equal to 0.2 micron. Combinations of these ranges are also possible (e.g. the filter may have a pore size of greater than or equal to 0.1 micron and less than or equal to 5 microns, greater than or equal to 0.2 micron and less than or equal to 4 microns, or greater than or equal to 0.3 micron and less than or equal to 3 microns). Other ranges are also possible.

[0087] The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention.

[0088] EXAMPLE 1

[0089] The following example describes a method involving lithium (e.g., lithium carbonate) extraction from lithium-containing brine coupled with CO2 capture.

[0090] The described technology has at least two purposes: (1) rapid, selective extraction of lithium from brines in a relatively simple process (FIG. 2, left-hand electrochemical cells), and (2) capture of CO2 and its simultaneous utilization as a raw material for lithium carbonate production (FIG. 2, right-hand spray tower). FIG. 3 shows how such a system may be integrated into an industrial process to treat a flue gas. In the first step, Li+was selectively extracted from brine in an electrochemical flow cell through capture on a lithium- selective electrode with an appropriate channel size for sieving lithium from other ions. In the second step, the captured Li+ions were released to, and concentrated in a clean recovery solution. Simultaneously, the pH of the recovery solution was increased by the capture of protons at the counter electrode, and the lithium selective electrode is regenerated and ready for the next lithium capture cycle. The solution was then introduced to the CO2 spray absorption tower, where the elevated pH shifts the carbonate-carbon dioxide equilibrium concentration toward CO32’, increasing the CO32’ concentration and producing a concentrated Li COa solution:

[0091] Therefore, this process can repeatedly and continuously extract lithium from brine and remove CO2 from either flue gas or atmospheric air to obtain a concentrated Li2COa solution.

[0092] The concentrated Li2COa solution was further heated up and concentrated in the evaporator, to yield solid Li2CO3. High recovery rates and stable operation of the process are possible from the hybrid electrochemical-thermal process because of the lowered solubility of Li2CO3 at a higher temperature, and increased concentration of Li2CO3 in the evaporator. In addition, with recycling of the remaining solution back to the electrochemical lithium recovery solution, supplemented by the condensed evaporated water at the top of the spray tower, continuous production of Li2CO3 with a high recovery rate is attained.

[0093] Traditional approaches for extracting lithium require significant land usage, water resources, and have an enormous environmental footprint, as shown below in Table 1. This makes it extremely challenging to extract lithium in the United States, thereby crucially impacting US energy access. The majority of the world’s lithium is produced from brine and traded in the form of lithium carbonate (Li2CO3). Mineral-rich brines are pumped to large shallow ponds, water is evaporated for more than a year, interrupting ions (e.g., magnesium, calcium) are sequentially precipitated by adding chemicals, and finally Li2CO3 is produced by adding large quantities of Na2CO3 to the solution. This process is only applicable for a narrow range of brines since efficiency depends on the difference in solubility between ions. The world's largest lithium production sites are located in South America, but the United States also has significant lithium reserves in Nevada and plans to expand capacity to meet the exponential growth in demand for lithium. However, the extensive land, water, and chemical footprint of the current Li extraction process poses a significant natural resource and environmental challenge, making it very difficult to implement it in the United States. The hybrid electrochemical-thermal example described for Li extraction is transformational as it solves a number of the above challenges in a fully integrated process. By using CO2 as a carbonate source instead of Na2COa, the enormous amounts of chemical additives may be eliminated while also mineralizing CO2 into a valuable end product. The preliminary calculations show that to meet a 50,000 tons Li2CO3 / year production target, the process needs a ~4MW power source and can mineralize about -81.5 tons / day of CO2. The CO2 needed for the process can be obtained from the flue gas emissions of the power plant itself as shown in FIG. 2 (-83 tons / day for coal powered or -30 ton / day for natural gas plant) and any additional CO2 needed can be obtained from direct air capture. The approach does not require large evaporation ponds, thereby reducing the land usage by several orders of magnitude and significantly shortening the timescales for Li extraction from years to days. By separating Li through the electrochemical process followed by thermal evaporation with simultaneous carbonation using CO2, the approach can eliminate enormous quantities of chemical additives as well as disposal brines (containing concentrated NaCl) used in the current process in addition to mineralizing CO2. Furthermore, water capture using electrostatic collectors can dramatically reduce the water footprint of the process, which is invaluable for the desert region of Nevada. For at least the above reasons, this approach can significantly minimize the environmental footprint and reduce any adverse impact on ecosystems. Finally, this lithium recovery system can extract lithium from brines containing many interrupting ions, broadening its applicability to wide range of Li sources including oil & gas brines, battery recycling, ocean and ground water brines, etc. The performance metrics and comparison to the current approach are summarized in Table 1 below.

[0094] Considering that lithium resources in the United States are 6.8 million tons, which is equivalent to -40% of that in Argentina, which is one of the largest lithium production sites, the potential impact of the approach of this example. Given the explosive demand for lithium, this approach can truly address American energy challenges by enabling economical and environmentally friendly extraction of lithium in the US. The described technology platform using CO2 mineralization is general enough that it can be extended to efficient extraction of other strategic metals and minerals (e.g., Ni, Co, rare earths).

[0095] Selection of electrode materials

[0096] For this system, the materials for the two electrodes should have at least the following purposes: (1) the active electrode should selectively capture lithium from a brine, and release to a sweep stream; and / or (2) the counter electrode should alkalize an aqueous solution by the selective capture of protons.

[0097] A number of candidate electrode pairs have been considered, with the most promising being selected for more in-depth application. Criteria for selection include materials cost, selectivity, long-term stability, and energetics of the process per mole Li2CO3 produced. Representative electrode pairs were chosen based on suitable pairwise combinations of the following electrochemical half-cell reactions:

[0098] (1) Spinel type manganese oxide (L-MnCL) or Olivine type lithium iron phosphate (FePO4) electrodes for capture / release of Li+:

[0099] (2) Metal oxides for capture and release of H+:

[0100] MO2+ H++ e HMO2 or bismuth oxychloride (BiOCl) for removal of H+with simultaneous release of Cl : BiOCl + 2H++ 3e Bi + Cl +H2O.

[0101] Design and fabrication of electrochemical system

[0102] The system of this example aims to obtain a highly concentrated Li COa solution and produce solid Li COa with a high recovery rate. The electrochemical component of the overall process captures Li+from a brine leaving other ions in solution to be utilized in a different manner or discarded, and then recover the Li+to a second solution as LiOH and / or LiCl. Since there is a limit to the amount of lithium that can be captured and released in one cycle per unit mass of electrode material, it was important to optimize the ratio of solution volume to electrode material to increase the production efficiency of the lithium solution fed to the CO2absorption and mineralization unit. The efficiency will also depend on overall cell dynamics, including electrode kinetics and mass transport limitations, which will depend on cell configuration and electrode placement. To this end, new interdigitated electrode configurations were considered to reduce inter-electrode distances, thereby increasing the electrolyte volume / electrode material ratio and overcoming possible ion transport and electrical resistances. Interdigitated electrodes can be fabricated using, at least, either screen-printing or inkjet printing methods, depending on the size of the electrodes being fabricated. Inkjet printing can produce interdigitated electrodes with feature sizes down to approximately 100 microns, while screen printing can enable feature sizes down to approximately 500 microns.

[0103] Development of thermal evaporative absorption-precipitation system

[0104] CO2 absorption into liquid media presents a fundamental bottleneck to the implementation of CO2 capture systems on a large scale. The combination of the dilute levels of CO2 present in a flue gas (2.5-20% volume) and the high flow rates of flue gas streams (-1500 m3 / h of gas) forces the need for high residence times and large interfacial areas between the liquid absorbent and the flue gas stream. As a result, powerplant- scale carbon capture requires relatively tall (10-40 m in height) and wide (10-20 m in diameter) absorber towers that also use packed beds to enhance interfacial area. These absorber towers can contribute to between 30-40% of the CAPEX of a carbon capture system and are a primary reason for such systems being limited to pilot scale installations. The efficiency of CO2 absorption was increased by moving away from packed beds and using sprayed droplets of the absorbent. For a given volume of fluid, the surface area to volume ratio achievable in a packed bed absorption tower scales as V = Apt Ap / V = / t, where V is the volume, Apis the interfacial area offered by the packed bed and t is the thickness of the film of absorbent on the packed bed. The surface area to volume ratio in the case of droplets scales as A^ / V ~ 1 / d where Ad is the surface area and d is the mean droplet diameter. Comparing the surface area-to-volume ratios of the two approached and using typical numbers for thickness of the absorbent in packed beds, it was found as described in this example that sprayed droplets can increase the interfacial area by 1-2 orders of magnitude. Beyond accelerating CO2 absorption, the large surface area to volume ratios of sprays was also beneficial for the evaporative concentration of the Li2COa product.

[0105] In one configuration, the CO2 absorption step was carried out by bubbling a CO2- containing gas stream through a solution comprising lithium cations. This system consisted of a sealed beaker containing 100 mL of LiOH solution at varying concentrations. A stream comprising a mixture of N2 and CO2, in which the concentration of CO2 varied from 5-95%, was bubbled into the stirred solution, while two electrodes measured the open circuit potential to monitor pH variations over time. The system included an outlet for the gas to flow through a CO2 sensor, which tracked the system’s CO2 capture efficiency and helped determine the mineralization rate. Additionally, a camera in timelapse mode recorded changes in the solution’s transparency due to precipitation. After precipitation, the solution was filtered, and lithium carbonate precipitate was collected. The results of these tests for LiOH solutions of varying concentrations are shown in Table 2 below.

[0106] Increasing lithium carbonate production of the hybrid system

[0107] In order to produce lithium carbonate with high recovery rate and energy efficiency using the described system, the balance between the electrochemical system and the thermal system was an important consideration. Specifically, temperature, recycling rate, amount of applied charge, and evaporation rate so that precipitation can be performed with high efficiency in the evaporator was considered.

[0108] Selective extraction using manganese oxide electrode

[0109] A step of the described system is to capture lithium selectively from brine and release it to the recovery solution. As there are a large number of other cations in brine, the importance of Li+extraction with high selectivity is emphasized to ensure Li COa with high purity is obtained. The A-MnOa electrode can be considered for selective Li+extraction, as it has an appropriate channel size for Li+with exclusion of other, larger cations. In one test, the potential for lithium capture and recovery from a simulated sea water containing Li+, Na+, Mg2+, and Ca2+was tested. The results in Table 2, below, indicated that the electrode system was able to effectively recover 40% of the lithium from the feed solution with very high selectivity relative to the other cations, which were present in significant excess. Considering that the ratio of other cations to Li+is much lower in the major target brines in the United States (e.g., 86.8, 0.352, 0.479 for Na+, Mg2+, Ca2+in Clayton Valley, Nevada), it is expected that lithium solutions with even higher purity can be obtained. The recovery fraction may also be increased through appropriate cell design with better solution-to-electrode volume ratios, while the product concentration can be enhanced significantly when the sweep stream volume used is lower than the volume of brine treated.

[0110] Table 3. Concentration of cations in simulated sea water and in the recovery solution

[0111] Electrochemical increase of pH for CO 2 mineralization

[0112] Another role of the electrochemical system is to generate a pH swing to enable CO2 or HCCh' to be converted to CCh2' in the absorption unit. For this purpose, a BiOCl electrode can be considered, as it can remove protons from solution when it is reduced to Bi. With a constant current applied to the BiOCl electrode in a solution containing 0.5 M NaCl and 2.5 mM NaHCCh, an apparent pH increase from 8.4 to 10 was observed in the effluent, shown in FIG. 4, which would allow for a high concentration of CO32’ in the solution. From this result, it is evident that the pH can be changed to be deeper in the basic region solely by applying an electric current to the cell, without the addition of chemicals. When used in combination with the lithium electrode in recovery mode, the Bi electrode readies the solution for the production of Li2CO3 in the absorber / evaporator.

[0113] Thermodynamic coupling of electrochemical Li+purification with Li2CC production in absorber

[0114] In the overall process, a lithium hydroxide solution is generated via electrochemically mediated purification of the brine feed with some degree of concentration, but further processing is required to obtain a commercially acceptable product, in this case a precipitate of Li2CO3. This precipitate is generated via mineralization of CO2 in a spray tower absorber situated downstream from the electrochemical cells. In the spray tower, a concentrated lithium hydroxide solution is sprayed into the tower from an apparatus at the top of the tower. The size of the lithium hydroxide solution droplets in this system can range from droplets as small as 0.1 micron to droplets on the scale of millimeters. Hot exhaust gas (at 400-500 °C) is injected into the spray tower from an apparatus at the bottom of the tower. As the droplets of the solution travel downwards through the tower, they are heated by the exhaust gas, and eventually evaporate and absorb carbon dioxide from the exhaust gas. These processes result in lithium carbonate precipitation. The remaining droplets with lithium carbonate are collected at the bottom of the tower, where lithium carbonate can be separated from the solution. The remaining liquid can be reused as an electrolyte in an electrochemical system.

[0115] The amount of carbonate formed in the spray tower depends on the solution conditions generated in the cells, which in turn depends on the charge transferred in these cells. FIG. 5 shows, via simulated data (derived using the equilibrium constants of the components of the system during lithium carbonate precipitation), how the concentration of each component in the solution varies when equilibrated at 25 °C in the spray tower with flue gas containing 15% CO2 as the charge transferred in the electrochemical cells increases, i.e., as the Li+concentration increases. With an initial Li+concentration of 0.1 M in the sweep stream fed to the regeneration cell, at low charge transfer insufficient Li+is released to take the product of the Li+and CO32’ concentrations above the solubility product, i.e., the solution is unsaturated, and thus precipitation does not occur. With increasing applied charge in the electrochemical cells, the amount of dissolved Li2COa produced in the spray tower increases. Once the solution reaches saturation, precipitation of over 90% of the lithium ion can be achieved. The remaining supernatant can then be combined with the water collected at the top of the absorber and recycled to be used as the sweep solution in the recovery step, allowing for Li2COa to be produced at a high recovery rate, with minimal loss of the lithium to the discard streams. FIG. 6 shows the scrubbing efficiency of the system for a variety of absorption tower lengths.

[0116] These calculations demonstrate the concepts, but do not include the evaporation of the water in the absorber, which will only enhance the precipitation rate; nor do they allow for the favorable effect of elevated temperatures on the solubility product. Such effects are considered in more detail below.

[0117] It is further expected that the combination of the electrochemical system with the thermal process could improve the performance of the overall process. FIGS. 7-8 show schematics of such integrated processes. The recovery rate can increase with the hybrid system because a more concentrated lithium solution can be obtained with a reduced applied charge and lowered solubility of Li2CO3 at a higher temperature. In addition, the possible deactivation of the electrode, which might be caused by precipitate formation in an electrochemical system, can be prevented by using an evaporator to induce precipitation, separated from the electrochemical system.

[0118] Spray capture o C

[0119] As discussed in more detail in the modeling section below, the CO2 absorption of into sprayed droplets can be determined by a multiscale, multiphysics model that combines thermal-fluidic and chemical transport. Compared to an identical packed bed system that would be about 10 m tall, the droplet spray system would only need about < 1 m to reach 90% capture efficiency. This Multiphysics modeling expertise can be include in designing and improving this thermal evaporation-absorption process.

[0120] Modeling and Simulations This effort will include reactive transport analysis of electrode cell operations during both the capture and release stages; simulations of thermal systems for brine concentration by evaporation, coupled with CO2 capture that will include a thermodynamic and dynamic analysis of solution and precipitation behavior and an overall integrated process model.

[0121] Modeling on electrochemical cell operations

[0122] A comprehensive thermodynamic model will be developed to predict equilibrium speciation under different conditions, and to estimate the energy requirement for lithium extraction and pH swing in preparation for conversion of CO2 to CO32’ in the absorber / evaporator. The electrochemical thermodynamic cycle can be constructed with the half-cell equilibrium potentials calculated according to the Nemst equation:8 where Eo is the standard electrode potential for the reactions, R is the gas constant (8.314 J mol-1K-1), T is the temperature (K), F is the Faraday constant (96485 C mol-1), and aH+ is the activity of protons. The ion activities can be calculated as: where Ci is the concentration, and y; is the activity coefficient estimated using, e.g., the extended Debye-Hiickel equation. This model has been used to estimate the CO2 capacity in ocean waters and potassium carbonate absorption systems, as mediated by the proton addition, with excellent agreement with experiments known in the literature.

[0123] The minimum electrochemical work (Wmin; in kJe / molLi2co3) needed to drive the reactions and recover Ei2CO3 can then be estimated as a function of the potential (from the Nernst equation), the solution pH and the applied current, via: where Fm,co2 is the molar rate of Ei+captured from the brine, and Eoxand Ered are the oxidation and reduction equilibrium potentials, respectively. The total electrical work required for the full operation will include also energy usage associated with pumping of the brine through the cells, and overpotentials needed to drive the process at acceptable capture and release rates. Additional energy required for the thermal absorber / evaporator part of the process calculated elsewhere will complete the estimate of the energy requirements for the overall process.

[0124] A transport model will be developed to predict the reaction rate and behavior of the electrochemical cell, information which will be needed to complete the overall system design and estimates of the process energetics. Mass balances and charge neutrality constraints, respectively, are where E is the volume fraction of the liquid phase, q is the concentration of species j, zj is its charge, D^is the effective diffusivity of the species j, F is Faraday constant, (ptis the electrolyte potential, u is the flow velocity vector, and Sj is the rate of species production or consumption. For the electrochemical capture / release at the electrodes, Sj

[0125] , v ;ai , for Li and Cl’, and S,- = — — fe for H , where v,- is the stoichiometric coefficient, a is active surface area, z is current density, n is the number of electrons participating in the electrochemical reaction, / is faradaic efficiency, and e is electron utilization. To calculate current (z) in the system, the Butler-Volmer equation can be introduced: aaFri acFri i = t0(e RT - e RT ) where z‘o is the exchange current density, >j is the overpotential, and aaand acare the anodic and cathodic reaction rate coefficients, respectively.

[0126] With these equations, the concentration of each species, the overpotential, and the current density distribution can be calculated to allow estimation of reaction rates and energy requirements for different electrode configurations for process optimization.

[0127] Modeling of thermal evaporative absorption-precipitation process

[0128] The LiOH solution from the electrochemical cell will be further concentrated via spray evaporation in a cooling tower along with simultaneous absorption of CO2 from flue gas. Flue gas streams from coal fired plants typically contain between 12-14% CO2 by volume. Capturing all the CO2 from such dilute sources requires optimizing the surface area to volume ratio of contact between the CO2 and LiOH solution and extending the contact time between the two fluids. Prior experience with cooling towers and wet chemical scrubbers to design a high-efficiency evaporation-absorption system. Accordingly, a multiscale, multiphysics transport models will be developed to allow for development of process phase diagrams that connect input parameters such as (i) physical parameters (ii) absorption kinetics, chemical evolution of pH and concentrations (iii) droplet parameters such size, distribution and entrainment characteristics to the yield. These will be accomplished by conducting (i) transport analysis at single droplet scale to obtain reaction and transport constants, and precipitation dynamics which will then be an input into the (ii) overall spray model. These multiphysics models will couple mass and energy balance, chemical kinetics, and nucleation and growth physics. The proposed spray approach enables increased interfacial area for the evaporation and absorption processes to occur. Examining what this enhancement in interfacial area would mean in terms of overall reduction of the absorber system, CO2 absorption into liquid droplets can be modeled using the mass transfer equation below. where mC02is the mass flux of CO2, A is the droplet area, k is the reaction constant, Cg,sis the CO2 concentration at the droplet interface, Ci,i is the initial sorbent concentration at the point where the droplets are introduced, Ci is the sorbent concentration in the droplet, D is the droplet diameter and a, , v, w, y, z are all empirical constants. This model assumes that the liquid droplets do not interact with each other and can be used to examine how modifications to individual droplets or sorbent concentrations can affect overall plant scale. Multiphysics hydrodynamic-chemical transport simulations will be developed that take into account evaporation, internal convection, interfacial absorption along with single-(LiOH)droplet experiments to establish the reaction and other concentration constants mentioned above in an overall transport model. This will input into the spray-level model and by using an iterative approach for a specific absorbent to gas flow rate ratio, the model can be used to examine the overall residence time and droplet parameters needed for a given gas flow rate to reach appropriate saturation concentrations for Li2COa precipitation.

[0129] Precipitation model

[0130] Here a complete thermodynamic -kinetic model for Li2COa precipitation in this process will be developed. The models will be developed based on nucleation theory, primary and secondary nucleation processes, and diffusion limited growth processes to describe the entire precipitation process. The Gibbs free energy barrier AG and the nucleation rate J for primary and secondary nucleation processes depend on interfacial energies and lattice mismatch, given by: where <jpis the primary cluster- solution interfacial energy and r* is the critical radius from Kelvin equation. The parameter m is the ratio of the interfacial energies (m = wherep, <7S, are the primary and secondary cluster interfacial energies, £ is the lattice mismatch, k is the Boltzmann constant, and Jois a kinetic constant [26-28]. Single droplet experiments will be conducted (see Sec. 2.3.3) to determine nucleation and growth parameters as functions of supernatant conditions. The concentrations obtained in the evaporation-absorption process transport model from above will be used to define the supers aturation regions and accordingly the precipitation rates as a function of the length of the column.

[0131] The thermal transport model can therefore relate the flue gas and LiOH flow rates, droplet parameters, precipitation formation rates, and water recovery rates to provide a framework for designing and optimizing the thermal system.

[0132] Overall integrated process model

[0133] An overall process flow model connecting the electrochemical and thermal processes will be developed. This model will track the overall balance of mass, charge, and energy to both balance the electrochemical and thermal reactors, and to serve as a valuable tool for overall process optimization.

[0134] Preparation and characterization of electrodes

[0135] Electrode Fabrication

[0136] For the lithium recovery electrode of the system, a LiM C composite electrode was fabricated first, and was converted to a k-MnCh electrode. LiJ h C particles were prepared using the solid-state or the coprecipitation method, or using commercial powder. The prepared LiMn2O4 went through acid treatment or electrochemical oxidation to be converted to A-MnCh. On the other hand, for the bismuth electrode, commercial powders were employed. The electrodes themselves were prepared by mixing these active materials with conducting agents (e.g., CNTs, carbon black particles) and polymeric binders in an organic solvent. For initial screening experiments and materials characterization, the resulting inks were deposited on conductive substrate swatches (2 cm x 2 cm) by the doctor-blade method to be used in two- and three- electrode screening tests. One such electrode is shown in FIG. 10.

[0137] Subsequently, the inks will be applied to a non-conductive substrate by inkjet or screen printing of the anode and cathode electroactive conductive materials in an interdigitated format, which will provide lower ionic resistance between the two electrodes and higher electrode area / electrolyte volume ratio than feasible in the separated electrode system. Specifically, each interdigitated electrode will consist of a conductive base layer, with conductive particles such as, e.g., silver nanoparticles (AgNP) and / or carbon nanotubes (CNT), upon which will be deposited the electrochemically active layer. Both inkjet printing and screen printing are relatively inexpensive and scalable methods to deposit controlled patterns of active materials with high resolution for electrode fabrication. These methods allow facile and precise electrode processing with flexibility with both the choice of material used and the geometry of the electrode design.

[0138] Material characterization

[0139] Fundamental characterization of electrode materials was carried out by X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS) to investigate their crystal structures and chemical states. The morphology and pore distribution of the electrodes were analyzed by scanning electron (SEM) and transmission electron (TEM) microscopy, and by Brunauer-Emmett-Teller (BET) analysis.

[0140] System performance (including electrochemical characterization)

[0141] The electrochemical system performance was assessed at both the individual compartment and the process level. For the individual compartments (e.g., electrode and electrolyte) various techniques were implemented including cyclic voltammetry, chronopotentiometry, and / or electrochemical impedance spectroscopy. For example, FIG. 11 A shows cyclic voltammetry data for a system with an LiMn2O4 working electrode, platinum counter electrode, and Ag / AgCl (KC1 saturated) reference electrode, with a 1 M LiCl electrolyte. The scan rate for the data shown was 4 mV / s. FIG. 11B shows chronopotentiometry data for a system with an LiM C working electrode, platinum counter electrode, and Ag / AgCl (KC1 saturated) reference electrode, with a 50 mM LiCl electrolyte and 2.5 mM NaHCOa.

[0142] For the process level evaluation, long-term potential- voltage profiles as well as the cyclic capacity were carefully monitored. The concentration of cation in the brine and recovery solution were measured by ICP-OES, ICP-MS, or IC (ion chromatography) to evaluate the purity of the lithium solution. Also, the pH and DIC (Dissolved Inorganic Carbon) in the solutions were measured by a pH probe and by the titration method, respectively. In addition, physicochemical characteristics of the electrodes were investigated with various materials characterization tools (e.g., XRD, XPS, and SEM) in order to detect any electrode material transformations that may occur during the operations. To verify that there were no metal ions in the water following the electrochemical process for Li2CO3 production, the concentration of metals (e.g., Mn, Bi, etc.) in the treated water was measured by ICP-MS.

[0143] Mineralization Experiments

[0144] Mineralization experiments were conducted in two steps: coarse and fine, where the coarse experiments helped down select the conditions for the finer high throughput experiments. The coarse experiments consisted of single-droplet studies at various supersaturation conditions. Carbonate formation was tracked by (1) imaging using birefringence microscopy (2) pH measurements, (3) turbidity, and (4) zeta potential (Zetasizer) with time. Bi-refringence imaging provided crystal formation and population density rates, solution pH will show kinetics of Li2CO3 formation, and together allow for calculation of induction time and nucleation rate. By starting with predetermined particles and measuring the particle growth rate along with turbidity and zeta potential measurements allowed for precipitation growth kinetics. Following complete precipitation, the mass of crystal precipitants on the surface can be measured, and SEM images can be taken of the resulting crystals. Given that the nucleation-growth process is highly stochastic, high throughput microfluidic droplet reactors can be utilized to provide statistically significant values for the nucleation parameters (FIG. 9). For example, such an approach has been utilized in the past for protein crystallization.

[0145] Machine learning tools may also be used to track the nucleation and growth rates from the microscopic images. These tools may provide the nucleation and growth parameters of L12CO3 precipitation as a function of supersaturation parameters. This data will be input into the overall thermal-fluidic model and is essential to optimize the overall thermal process to determine the sprayed droplet parameters (for given flue gas flow rates and other tower parameters) in order to reach optimal supers aturation conditions for rapid precipitation. Taken together, these efforts allow us to design an optimal thermal evaporation-absorption-precipitation system that integrates efficiently with the electrochemical system.

[0146] Fabrication of integrated, bench-scale demonstration unit of hybrid system

[0147] An integrated bench-scale demonstration unit can be constructed to include pairs of electrode cells for the Li ion capture and release swing operations, and a spray absorption column for the capture and mineralization of CO2. The continuous operation of the unit can be fully supervised by a LabView script to control all pumps and valves, and to interrogate on-line analytical sensors (mass flow controllers, conductivity, pH, FT-IR, UV-Vis, temperature, etc.).

[0148] Fabrication of integrated bench-scale demonstration unit of hybrid system

[0149] An integrated bench-scale demonstration unit can be constructed to include pairs of electrode cells for the Li ion capture and release swing operations, and a spray absorption column for the capture and mineralization of CO2. The continuous operation of the unit can be fully supervised by a LabView script to control all pumps and valves, and to interrogate on-line analytical sensors (mass flow controllers, conductivity, pH, FT-IR, UV-Vis, temperature, etc.).

[0150] While several embodiments of the present disclosure have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is / are used. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0151] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0152] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0153] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0154] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0155] Some embodiments may be embodied as a method, of which various examples have been described. The acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and / or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

[0156] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0157] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMSWhat is claimed is:

1. A system, comprising: an electrochemical cell configured to capture a cation with a first applied voltage and release the cation with a second applied voltage; a capture container configured to receive a compound comprising the cation, the capture container associated with a heating element; and a conduit in fluidic communication with the capture container and configured to provide carbon dioxide to the capture container.

2. The system of any one of the preceding claims, wherein the cation comprises lithium, sodium, potassium, rubidium, and / or cesium.

3. The system of the preceding claim, wherein the cation comprises lithium.

4. The system of any one of the preceding claims, wherein the cation comprises an alkali metal cation.

5. The system of any one of the preceding claims, wherein the electrochemical cell comprises a first electrode and a second electrode.

6. The system of any one of the preceding claims, wherein the electrochemical cell comprises a first electrode configured to capture Li+ions and a second electrode configured to release H+ions.

7. The system of any one of the preceding claims, wherein the electrochemical cell comprises a lithium- selective electrode.

8. The system of any one of the preceding claims, wherein the electrochemical cell comprises a manganese oxide compound and / or an iron phosphate compound.

9. The system of any one of the preceding claims, wherein the electrochemical cell comprises a bismuth compound.

10. The system of any one of the preceding claims, wherein the capture container is configured to withstand a pH of less than or equal to 10 and greater than or equal to 0.

11. The system of any one of the preceding claims, wherein the conduit is configured to withstand a pH of less than or equal to 10 and greater than or equal to 0.

12. The system of any one of the preceding claims, further comprising a concentrating container in fluidic communication with the electrochemical cell and in fluidic communication with the capture container, the concentration container configured to receive a compound comprising the cation.

13. The system of claim 12, wherein the concentrating container comprises a concentrating element.

14. The system of claim 13, wherein the concentrating element comprises an electrolyzer.

15. The system of claim 13, wherein the concentrating element comprises a heating element.

16. A method for producing lithium carbonate, the method comprising: flowing a first stream comprising metal cations to a capture container; flowing a second stream comprising carbon dioxide to the capture container; heating the capture container to remove at least a portion of solvent from the first stream; and precipitating metal carbonate.

17. A method for capturing carbon dioxide, the method comprising: flowing a stream comprising carbon dioxide through a conduit to a capture container comprising a solvent and cations;reacting the carbon dioxide with the cations; heating the capture container to remove at least a portion of solvent from the container; and precipitating a carbonate compound.

18. A method for capturing carbon dioxide, the method comprising: flowing a first stream comprising cations and a solvent to a capture container; flowing a second stream comprising the carbon dioxide to the capture container; heating the capture container to remove at least a portion of the solvent from the first stream; reacting the carbon dioxide with the cations; and precipitating a carbonate compound.

19. A method for capturing carbon dioxide, the method comprising: flowing a brine comprising a solvent, a cation of interest, and an undesired cation to an electrochemical cell; performing at least one reaction in the electrochemical cell to remove the undesired cation from the brine and form a first stream comprising the cation of interest; flowing the first stream to a capture container; flowing a second stream comprising the carbon dioxide to the capture container; heating the capture container to remove at least a portion of the solvent from the first stream; reacting the carbon dioxide with the cation of interest; and precipitating a carbonate compound.

20. The method of any one of the preceding claims, further comprising flowing the first stream comprising cations to a concentrating container and flowing the first stream from the concentrating container to the capture container.

21. The method of claim 14, further comprising, within the concentrating container, increasing the concentration of a species in the first stream.

22. The method of any one of the preceding claims, wherein the first stream comprises water.

23. The method of any one of the preceding claims, wherein the cation comprises lithium cations.

24. The method of any one of the preceding claims, wherein the second stream is from a power plant and / or from a flue.

25. The method of any one of the preceding claims, wherein the capture container is configured to withstand a pH of less than or equal to 10 and greater than or equal to 0.

26. The method of any one of the preceding claims, wherein heating is provided by a heating element associated with the capture container.

27. The method of any one of the preceding claims, wherein the carbonate compound comprises lithium carbonate.

28. The method of any one of the preceding claims, further comprising isolating the carbonate compound from the capture container.

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