Method and apparatus for electrochemical ion exchange

Abstract

The present disclosure generally relates to devices and methods for extracting ions, including lithium ions. For example, certain aspects generally relate to electrochemical ion exchange techniques in which the ion exchange is electrically driven. In some embodiments, a fluid rich in target ions (e.g., a feed solution) may be present in a compartment housing a target ion selective electrode, and target ions from the fluid may be incorporated into the electrode, for example by applying a suitable current to drive ion exchange. At a second time, the target ions may be removed from the electrode, e.g., into a target ion lean fluid (e.g., recovery solution), e.g., by applying a suitable current to drive ion exchange. In addition, certain embodiments generally relate to stacks of such compartments.

Description

[0001] Related applications

[0002] This application claims the benefit of the following patent applications: U.S. Provisional Patent Application Serial No. 63 / 440,889, filed January 24, 2023, entitled “Methods and Apparatuses for Galvanic Ion Extraction”; U.S. Provisional Patent Application Serial No. 63 / 444,484, filed February 9, 2023, entitled “Flow Field Configurations and Methods for Separation Process”; U.S. Provisional Patent Application Serial No. 63 / 513,519, filed July 13, 2023, entitled “Methods and Apparatuses for Electrochemical Ion Exchange”; and U.S. Provisional Patent Application Serial No. 63 / 513,519, filed July 13, 2023, entitled “Process and Apparatuses for Enriching”. U.S. Provisional Patent Application Serial No. 63 / 513,532, entitled “Solutions [Methods and Apparatus for Enriching Solutions]”; and U.S. Provisional Patent Application Serial No. 63 / 513,538, filed July 13, 2023, entitled “Flow Systems and Methods for Membraneless Separation”. Each of these patent applications is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to apparatus and methods for extracting ions, including lithium ions. Background Technology

[0004] Ion exchange is frequently used in many industrial processes, such as for exchanging calcium ions for sodium ions in water softening. Ion exchange involves the use of specialized resin materials with an affinity for the target ions in the fluid. Once fully saturated, the resin can be regenerated via chemical treatment, such as by exposing it to hydrochloric acid. However, the use and disposal of such chemical regenerators are major drawbacks of ion exchange, thus limiting its application. Therefore, improvements to ion exchange methods are needed. Summary of the Invention

[0005] This disclosure generally relates to apparatus and methods for extracting ions, including lithium ions. In some cases, the subject matter of this disclosure relates to related products, alternative solutions to specific problems, and / or a variety of different uses of one or more systems and / or articles.

[0006] In some respects, ion exchange can be carried out without the need for chemical regenerators, as discussed herein. For example, according to certain embodiments, ion exchange can be electrically driven, for example, in a forward or reverse direction. For example, in some cases, the active elements (electrodes) can be electrically discharged to regenerate them.

[0007] As examples, a set of embodiments generally relates to an electrochemical battery cell or compartment including a first electrode and a second electrode. Fluid may be present in and / or flow through the compartment. The fluid within the compartment may include a feed solution (e.g., a lithium-rich or other target ion-rich solution) or a recovery solution (e.g., a lithium-poor or other target ion-poor solution), depending on the application and operating mode. In one embodiment, during discharge, the feed solution may be present in or flow through the compartment, and the first electrode may selectively remove cations (e.g., lithium) from the feed solution, while the second electrode may discharge other cations (e.g., magnesium) into the feed solution. During charging, the recovery solution may be present in or flow through the compartment, and the recovery solution may accept cations (e.g., lithium) discharged from the first electrode, while the second electrode may remove other cations (e.g., magnesium) from the recovery solution. Other examples of cations are described below. These operations can be driven by applying current to the electrodes. Furthermore, in some embodiments (such as those discussed herein), recovery stream purification and cation recovery can be performed simultaneously.

[0008] Additionally, some embodiments generally relate to methods or apparatus for extracting target ions (e.g., metal ions such as lithium or other ions) from a multi-component aqueous solution containing certain target ions via electro-oscillation adsorption or other processes. In some cases, the apparatus may include one or more compartments (e.g., a stack of compartments) housing a target ion-selective working electrode and a divalent, polyvalent, or monovalent cation-selective counter electrode. Some or all of the compartments may contain fluid or allow fluid flow, for example, in which feed and recovery solutions may be exchanged, respectively, during cycles of target ion extraction and release. Furthermore, the counter electrode may be used to selectively electro-adsorb target cations during cell charging and desorb them during cell discharging, and / or to selectively electro-adsorb target anions during cell discharging and desorb them during cell charging.

[0009] One aspect generally relates to an apparatus for the electrochemical extraction of lithium. In one set of embodiments, the apparatus includes a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode; an electrical pathway connecting the lithium-selective electrode and the divalent and / or multivalent cation-selective electrode; a lithium-rich fluid source; a lithium-lean fluid source; and a flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-lean fluid source into the compartment.

[0010] In another set of embodiments, the device includes a stack comprising a plurality of repeating units, each repeating unit including a compartment and an electrical pathway, the compartment accommodating a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode, the electrical pathway connecting the lithium-selective electrode and the divalent and / or multivalent cation-selective electrode; a lithium-rich fluid source; a lithium-lean fluid source; and a flow switching element capable of directing fluid from the lithium-rich or lithium-lean fluid source into the compartment within the stack.

[0011] Another aspect generally relates to an apparatus for the electrochemical extraction of target monovalent ions. In one set of embodiments, the apparatus includes a compartment housing a target monovalent ion-selective electrode and a multivalent cation-selective electrode; an electrical pathway connecting the target monovalent ion-selective electrode and the multivalent cation-selective electrode; a target monovalent ion-rich fluid source; a target monovalent ion-poor fluid source; and a flow switching element capable of directing fluid from either the target monovalent ion-rich or target monovalent ion-poor source into the compartment.

[0012] In another embodiment, the device includes a stack comprising a plurality of repeating units, each repeating unit including a compartment and an electrical pathway, the compartment accommodating a target monovalent ion selective electrode and a multivalent cation selective electrode, the electrical pathway connecting the target monovalent ion selective electrode and the multivalent cation selective electrode; a target monovalent ion rich source; a target monovalent ion poor source; and a flow switching element capable of directing fluid from the target monovalent ion rich source or the target monovalent ion poor source into the compartment within the stack.

[0013] Another aspect generally relates to an apparatus for the electrochemical extraction of lithium. In one set of embodiments, the apparatus includes a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; an electrical pathway connecting the lithium-selective electrode and the monovalent cation-selective electrode; a lithium-rich fluid source; a lithium-lean fluid source; and a flow switching element capable of directing fluid from either the lithium-rich or lithium-lean fluid source into the compartment.

[0014] In another embodiment, the device includes a stack comprising a plurality of repeating units, each repeating unit including a compartment and an electrical pathway, the compartment accommodating a lithium-selective electrode and a monovalent cation-selective electrode, the electrical pathway connecting the lithium-selective electrode and the monovalent cation-selective electrode, wherein the monovalent cation is not lithium; a lithium-rich fluid source; a lithium-lean fluid source; and a flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-lean fluid source into the compartment within the stack.

[0015] In another aspect, the device can be an apparatus for electrochemical extraction of target monovalent ions. In one set of embodiments, the device includes a compartment housing a target monovalent ion-selective electrode and a non-target monovalent cation-selective electrode; an electrical pathway connecting the target monovalent ion-selective electrode and the multivalent cation-selective electrode; a target monovalent ion-rich fluid source; a target monovalent ion-poor fluid source; and a flow switching element capable of directing fluid from either the target monovalent ion-rich or target monovalent ion-poor source into the compartment.

[0016] In another embodiment, the device includes a stack comprising a plurality of repeating units, each repeating unit including a compartment and an electrical pathway, the compartment accommodating a target monovalent ion-selective electrode and a non-target monovalent cation-selective electrode, the electrical pathway connecting the target monovalent ion-selective electrode and the non-target monovalent cation-selective electrode; a target monovalent ion-rich fluid source; a target monovalent ion-poor fluid source; and a flow switching element capable of directing fluid from the target monovalent ion-rich or target monovalent ion-poor fluid source into the compartment within the stack.

[0017] Another aspect generally relates to a method for electrochemically extracting lithium. In one set of embodiments, the method includes providing an electrochemical cell unit comprising a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode; at a first time, causing current to flow from the lithium-selective electrode to the divalent and / or multivalent cation-selective electrode while a lithium-rich fluid flows through the compartment; and at a second time, causing current to flow from the divalent and / or multivalent cation-selective electrode to the lithium-selective electrode while a lithium-depleted fluid flows through the compartment.

[0018] According to another set of embodiments, the method includes providing an electrochemical cell unit comprising a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode; at a first time, allowing a lithium-rich fluid to flow through the compartment to bind lithium ions from the lithium-rich fluid to the lithium-selective electrode and to remove divalent and / or multivalent cation-selective electrodes from the divalent and / or multivalent cation-selective electrodes into the lithium-rich fluid; and at a second time, allowing a lithium-depleted fluid to flow through the compartment to remove lithium ions from the lithium-selective electrode into the lithium-depleted fluid and to bind divalent and / or multivalent cation-selective electrodes from the lithium-depleted fluid.

[0019] In another aspect, the method is a method for electrochemically extracting target monovalent ions. In one set of embodiments, the method includes providing an electrochemical cell unit including a compartment housing a target monovalent ion-selective electrode and a multivalent cation-selective electrode; at a first time, causing a current to flow from the target monovalent ion-selective electrode to the multivalent cation-selective electrode while a target monovalent ion-rich fluid flows through the compartment; and at a second time, causing a current to flow from the multivalent cation-selective electrode to the target monovalent ion-selective electrode while a target monovalent ion-poor fluid flows through the compartment.

[0020] According to another set of embodiments, the method includes providing an electrochemical cell unit, the electrochemical cell unit including a compartment housing a target monovalent ion selective electrode and a multivalent cation selective electrode; at a first time, flowing a target monovalent ion-rich fluid through the compartment to bind target monovalent ions from the target monovalent ion-rich fluid to the target monovalent ion selective electrode and removing multivalent cations from the multivalent cation selective electrode to the target monovalent ion-rich fluid; and at a second time, flowing a target monovalent ion-poor fluid through the compartment to remove target monovalent ions from the target monovalent ion selective electrode to the target monovalent ion-poor fluid and binding multivalent cations from the target monovalent ion-poor fluid to the multivalent cation selective electrode.

[0021] Another aspect relates to a method for electrochemically extracting lithium. In one set of embodiments, the method includes providing an electrochemical cell unit comprising a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; causing current to flow from the lithium-selective electrode to the monovalent cation-selective electrode at a first time while allowing a lithium-rich fluid to flow through the compartment; and causing current to flow from the monovalent cation-selective electrode to the lithium-selective electrode at a second time while allowing a lithium-depleted fluid to flow through the compartment.

[0022] In another embodiment, the method includes providing an electrochemical cell unit comprising a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; at a first time, allowing a lithium-rich fluid to flow through the compartment to bind lithium ions from the lithium-rich fluid to the lithium-selective electrode and remove the monovalent cation from the monovalent cation-selective electrode into the lithium-rich fluid; and at a second time, allowing a lithium-depleted fluid to flow through the compartment to remove lithium ions from the lithium-selective electrode into the lithium-depleted fluid and bind the monovalent cation from the lithium-depleted fluid to the monovalent cation-selective electrode.

[0023] Another aspect generally relates to a method for electrochemically extracting a target monovalent ion. In one set of embodiments, the method includes providing an electrochemical cell unit comprising a compartment housing a target monovalent ion-selective electrode and a non-target monovalent cation-selective electrode; at a first time, causing a current to flow from the target monovalent ion-selective electrode to the non-target monovalent cation-selective electrode while a target monovalent ion-rich fluid flows through the compartment; and at a second time, causing a current to flow from the non-target monovalent cation-selective electrode to the target monovalent ion-selective electrode while a target monovalent ion-poor fluid flows through the compartment.

[0024] In another embodiment, the method includes providing an electrochemical cell unit comprising a compartment housing a target monovalent ion selective electrode and a non-target monovalent cation selective electrode; at a first time, flowing a target monovalent ion-rich fluid through the compartment to bind target monovalent ions from the target monovalent ion-rich fluid to the target monovalent ion selective electrode and removing non-target monovalent cations from the non-target monovalent cation selective electrode to the target monovalent ion-rich fluid; and at a second time, flowing a target monovalent ion-poor fluid through the compartment to remove target monovalent ions from the target monovalent ion selective electrode to the target monovalent ion-poor fluid and binding non-target monovalent cations from the target monovalent ion-poor fluid to the non-target monovalent cation selective electrode.

[0025] In some aspects, the method is a method for electrochemically extracting lithium. According to one set of embodiments, the method includes providing a stack comprising a plurality of repeating units, each repeating unit comprising a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode, wherein the compartments comprise a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, causing current to flow from the lithium-selective electrode to the divalent and / or multivalent cation-selective electrode while a lithium-rich fluid flows through the first set of compartments, and causing current to flow from the divalent and / or multivalent cation-selective electrode to the lithium-selective electrode while a lithium-depleted fluid flows through the second set of compartments; and at a second time, causing current to flow from the lithium-selective electrode to the divalent and / or multivalent cation-selective electrode while a lithium-rich fluid flows through the second set of compartments, and causing current to flow from the divalent and / or multivalent cation-selective electrode to the lithium-selective electrode while a lithium-depleted fluid flows through the first set of compartments.

[0026] In another set of embodiments, the method includes providing a stack comprising a plurality of repeating units, each repeating unit comprising a compartment accommodating a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode, wherein the compartment comprises a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, causing current to flow from the lithium-selective electrode to the divalent and / or multivalent cation-selective electrode while allowing lithium-rich fluid to flow through the first set of compartments; and at a second time, causing current to flow from the lithium-selective electrode to the divalent and / or multivalent cation-selective electrode while allowing lithium-rich fluid to flow through the second set of compartments.

[0027] In yet another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, a lithium-rich fluid is flowed through the first set of compartments and a lithium-depleted fluid is flowed through the second set of compartments, such that lithium ions from the lithium-rich fluid bind to the lithium-selective electrode in the first set of compartments and divalent and / or multivalent cations are removed from the divalent and / or multivalent cation-selective electrode into the lithium-rich fluid, and in the second set of compartments... In the first phase, lithium ions are removed from the lithium selective electrode into a lithium-depleted fluid, and divalent and / or polyvalent cations from the lithium-depleted fluid are bound to the divalent and / or polyvalent cation selective electrode; and in the second phase, a lithium-rich fluid is flowed through a second set of compartments, and a lithium-depleted fluid is flowed through a first set of compartments, such that in the second set of compartments, lithium ions from the lithium-rich fluid are bound to the lithium selective electrode and divalent and / or polyvalent cations are removed from the divalent and / or polyvalent cation selective electrode into the lithium-rich fluid, and in the first set of compartments, lithium ions are removed from the lithium selective electrode into the lithium-depleted fluid, and divalent and / or polyvalent cations from the lithium-depleted fluid are bound to the divalent and / or polyvalent cation selective electrode.

[0028] In another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit comprising a compartment housing a lithium-selective electrode and a divalent and / or multivalent cation-selective electrode, wherein the compartments comprise a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, allowing a lithium-rich fluid to flow through the first set of compartments, such that lithium ions from the lithium-rich fluid in the first set of compartments bind to the lithium-selective electrode and remove divalent and / or multivalent cations from the divalent and / or multivalent cation-selective electrode into the lithium-rich fluid; and at a second time, allowing the lithium-rich fluid to flow through the second set of compartments, such that lithium ions from the lithium-rich fluid in the second set of compartments bind to the lithium-selective electrode and remove divalent and / or multivalent cations from the divalent and / or multivalent cation-selective electrode into the lithium-rich fluid.

[0029] In another set of embodiments, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a target monovalent ion-selective electrode and a divalent and / or multivalent cation-selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, causing a current to flow from the target monovalent ion-selective electrode to the divalent and / or multivalent cation-selective electrode while allowing a target monovalent ion-rich fluid to flow through the first set of compartments; and at a second time, causing a current to flow from the target monovalent ion-selective electrode to the divalent and / or multivalent cation-selective electrode while allowing a target monovalent ion-rich fluid to flow through the second set of compartments.

[0030] In yet another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a target monovalent ion selective electrode and a divalent and / or multivalent cation selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, a target monovalent ion-rich fluid is flowed through the first set of compartments and a target monovalent ion-poor fluid is flowed through the second set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid bind to the target monovalent ion selective electrode in the first set of compartments and divalent and / or multivalent cation selective electrodes are removed from the divalent and / or multivalent cation selective electrodes into the target monovalent ion-rich fluid, and target monovalent ions are removed from the target monovalent ion selective electrodes in the second set of compartments. The target monovalent ion selectively removes ions from the target monovalent ion selective electrode into the target monovalent ion-depleted ion fluid and the divalent and / or polyvalent ions from the target monovalent ion-depleted ion fluid bind to the divalent and / or polyvalent ion selective electrode; and at a second time, the target monovalent ion rich fluid flows through a second set of compartments and the target monovalent ion depleted fluid flows through a first set of compartments, such that in the second set of compartments, target monovalent ions from the target monovalent ion rich fluid bind to the target monovalent ion selective electrode and the divalent and / or polyvalent ions are removed from the divalent and / or polyvalent ion selective electrode into the target monovalent ion rich fluid, and in the first set of compartments, target monovalent ions are removed from the target monovalent ion selective electrode into the target monovalent ion-depleted ion fluid and the divalent and / or polyvalent ions from the target monovalent ion depleted ion fluid bind to the divalent and / or polyvalent ion selective electrode.

[0031] In another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a target monovalent ion selective electrode and a divalent and / or multivalent cation selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, flowing a target monovalent ion-rich fluid through the first set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid in the first set of compartments bind to the target monovalent ion selective electrode and remove divalent and / or multivalent cations from the divalent and / or multivalent cation selective electrode into the target monovalent ion-rich fluid; and at a second time, flowing the target monovalent ion-rich fluid through the second set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid in the second set of compartments bind to the target monovalent ion selective electrode and remove divalent and / or multivalent cation selective electrodes from the divalent and / or multivalent cation selective electrode into the target monovalent ion-rich fluid.

[0032] In another set of embodiments, the method includes providing a stack comprising a plurality of repeating units, each repeating unit comprising a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode (e.g., where the monovalent cation is not lithium), wherein the compartments comprise a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; causing current to flow from the lithium-selective electrode to the monovalent cation-selective electrode at a first time while allowing lithium-rich fluid to flow through the first set of compartments; and causing current to flow from the lithium-selective electrode to the monovalent cation-selective electrode at a second time while allowing lithium-rich fluid to flow through the second set of compartments.

[0033] In yet another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, a lithium-rich fluid is flowed through the first set of compartments and a lithium-depleted fluid is flowed through the second set of compartments, such that lithium ions from the lithium-rich fluid in the first set of compartments bind to the lithium-selective electrode and remove monovalent cations from the monovalent cation-selective electrode into the lithium-rich fluid, and Furthermore, in the second set of compartments, lithium ions are removed from the lithium selective electrode into the lithium-depleted fluid, and monovalent cations from the lithium-depleted fluid bind to the monovalent cation selective electrode; and at a second time, lithium-rich fluid flows through the second set of compartments and lithium-depleted fluid flows through the first set of compartments, such that in the second set of compartments, lithium ions from the lithium-rich fluid bind to the lithium selective electrode and monovalent cations are removed from the monovalent cation selective electrode into the lithium-rich fluid, and in the first set of compartments, lithium ions are removed from the lithium selective electrode into the lithium-depleted fluid, and monovalent cations from the lithium-depleted fluid bind to the monovalent cation selective electrode.

[0034] In another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, allowing a lithium-rich fluid to flow through the first set of compartments, such that lithium ions from the lithium-rich fluid bind to the lithium-selective electrode in the first set of compartments and remove monovalent cations from the monovalent cation-selective electrode into the lithium-rich fluid; and at a second time, allowing the lithium-rich fluid to flow through the second set of compartments, such that lithium ions from the lithium-rich fluid bind to the lithium-selective electrode in the second set of compartments and remove monovalent cations from the monovalent cation-selective electrode into the lithium-rich fluid.

[0035] In another set of embodiments, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a target monovalent ion-selective electrode and a non-target monovalent cation-selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, causing a current to flow from the target monovalent ion-selective electrode to the non-target monovalent cation-selective electrode while allowing a target monovalent ion-rich fluid to flow through the first set of compartments; and at a second time, causing a current to flow from the target monovalent ion-selective electrode to the non-target monovalent cation-selective electrode while allowing a target monovalent ion-rich fluid to flow through the second set of compartments.

[0036] In yet another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment housing a target monovalent ion selective electrode and a non-target monovalent cation selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, a target monovalent ion-rich fluid is flowed through the first set of compartments and a target monovalent ion-poor fluid is flowed through the second set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid bind to the target monovalent ion selective electrode in the first set of compartments and non-target monovalent cations are removed from the non-target monovalent cation selective electrode to the target monovalent ion-rich fluid, and target monovalent ions are removed from the target monovalent ion selective electrode in the second set of compartments. In the ion-selective electrode, non-target monovalent cations are removed from the target monovalent ion fluid and bound to the non-target monovalent ion selective electrode; and at a second time, a target monovalent ion fluid rich in ions flows through a second set of compartments and a target monovalent ion fluid poor in ions flows through a first set of compartments, such that in the second set of compartments, target monovalent ions from the target monovalent ion fluid rich in ions bind to the target monovalent ion selective electrode and non-target monovalent cations are removed from the non-target monovalent ion selective electrode to the target monovalent ion fluid, and in the first set of compartments, target monovalent ions are removed from the target monovalent ion selective electrode to the target monovalent ion fluid poor in ions and non-target monovalent cations from the target monovalent ion fluid poor in ions bind to the non-target monovalent ion selective electrode.

[0037] In another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit including a compartment containing a target monovalent ion selective electrode and a non-target monovalent cation selective electrode, wherein the compartments include a first set of compartments and a second set of compartments, the compartments in the first set of compartments and the compartments in the second set of compartments alternating within the stack; at a first time, flowing a target monovalent ion-rich fluid through the first set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid bind to the target monovalent ion selective electrode in the first set of compartments and remove non-target monovalent cations from the non-target monovalent cation selective electrode into the target monovalent ion-rich fluid; and at a second time, flowing the target monovalent ion-rich fluid through the second set of compartments, such that target monovalent ions from the target monovalent ion-rich fluid bind to the target monovalent ion selective electrode in the second set of compartments and remove non-target monovalent cations from the non-target monovalent cation selective electrode into the target monovalent ion-rich fluid.

[0038] In yet another embodiment, the method includes providing a stack comprising a plurality of repeating units, each repeating unit comprising a compartment accommodating a target monovalent ion selective electrode and a divalent cation selective electrode; at a first time, flowing a target monovalent ion-rich fluid through the compartment such that target monovalent ions from the target monovalent ion-rich fluid bind to the target monovalent ion selective electrode and divalent cations are removed from the divalent cation selective electrode into the target monovalent ion-rich fluid; and at a second time, flowing a target monovalent ion-poor fluid through the compartment such that target monovalent ions are removed from the target monovalent ion selective electrode into the target monovalent ion-poor fluid and divalent cations from the target monovalent ion-poor fluid bind to the divalent cation selective electrode.

[0039] In another aspect, this disclosure covers methods of manufacturing one or more embodiments described herein, such as apparatus for electrochemical ion extraction of a target cation (e.g., lithium). In yet another aspect, this disclosure covers methods of using one or more embodiments described herein, such as apparatus for electrochemical ion extraction of a target cation (e.g., lithium).

[0040] Other advantages and novel features of this disclosure will become apparent from the following detailed description of various non-limiting embodiments of this disclosure when considered in conjunction with the accompanying drawings. Attached Figure Description

[0041] Non-limiting embodiments of this disclosure will be described by way of example with reference to the accompanying drawings, which are schematic and not intended to be drawn to scale. In the drawings, each identical or substantially identical component shown is typically represented by a single number. For clarity, not every component is labeled in each drawing, nor is every component of each embodiment of this disclosure shown, unless illustrated to the effect of this disclosure on those skilled in the art. In the drawings:

[0042] Figure 1A-1B In one embodiment, lithium and divalent ions (M) are shown. 2+ Electrochemical ion exchange;

[0043] Figure 2A-2B In another embodiment, lithium and different monovalent ions (M) are shown. + Electrochemical ion exchange;

[0044] Figures 3A-3B In yet another embodiment, lithium, anion (A) is shown - ) and divalent ions (M 2+ Electrochemical ion exchange;

[0045] Figures 4A-4BMultiple cycles of lithium extraction and removal are shown in another embodiment;

[0046] Figure 5 A compartment with three sets of electrodes is shown according to one embodiment;

[0047] Figure 6 A stack of compartments is shown in another embodiment; and

[0048] Figure 7 A device with a flow-through electrode is shown in yet another embodiment. Detailed Implementation

[0049] This disclosure generally relates to apparatus and methods for extracting ions, including lithium ions. For example, certain aspects generally relate to electrochemical ion exchange technology, wherein the ion exchange is electrically driven. In some embodiments, a fluid rich in target ions (e.g., a feed solution) may be present in a compartment housing a target ion-selective electrode, and the target ions from the fluid may be bound to the electrode, for example, by applying a suitable current to drive the ion exchange. At a second time, the target ions may be removed from the electrode, for example, by applying a suitable current to drive the ion exchange, for example, by removing the target ion-depleted fluid (e.g., a recovery solution). Additionally, some embodiments generally relate to stacks of such compartments.

[0050] Certain aspects generally relate to apparatus and methods for removing target ions (such as lithium) from a rich target ion fluid (e.g., a feed solution) and transferring them to a lean target ion fluid (e.g., a recovery solution) using various electrochemical ion exchange techniques. An example of such an apparatus is now described. The apparatus in this example can be used to extract lithium ions from a first fluid (e.g., a fluid with a relatively high concentration of lithium ions, i.e., a lithium-rich fluid) and add them to a second fluid (e.g., a fluid with a relatively low concentration of lithium ions, i.e., a lithium-lean fluid).

[0051] The first fluid can be, for example, brine from a salt lake, underground brine, geothermal brine, seawater, leach liquor from hard rock mining, leachate from lithium-ion battery recovery, or other potential lithium-ion sources. In some embodiments, such fluids may also contain high concentrations of other co-ions (e.g., cations or positively charged ions) such as sodium, calcium, magnesium, potassium, or other competing ions, and high concentrations of counter ions (e.g., anions or negatively charged ions) such as chloride ions, sulfate ions, hydroxide ions, etc. The second fluid can be, for example, fresh water, naturally occurring water, desalinated water, distilled water, etc., which can then concentrate lithium ions (without concentrating other co-ions) as described in this example, for example, for subsequent processing or use. Thus, lithium ions from the first fluid can become purified and / or concentrated in the second fluid. Furthermore, it should be understood that while this example describes the purification of lithium ions, this is only for ease of presentation, and in other embodiments (such as those described herein), various ion-selective electrodes (such as those described herein) can be used, for example, to separate ions other than lithium.

[0052] Now, a non-limiting example of this device will be described with reference to Figure 1. Figure 1A In the diagram, device 10 is shown having a compartment 20, a lithium-selective electrode 30, and a multivalent cation-selective electrode 40. In some cases, the electrodes can be connected via an electrical path 50, and a voltage source 60 can be used to drive current through the electrodes. A fluid 80 can be present within the compartment 20 and, in some cases, can flow through the compartment, for example... Figure 1A As shown in the image.

[0053] According to certain embodiments, devices such as these can be used to remove lithium ions from a first fluid and add them to a second fluid. For example, in a first moment, when current is applied to the electrodes of such a device, for example via a voltage source, lithium ions can act as charge carriers at the lithium-selective electrode and be driven into the lithium-selective electrode, for example by combining with electrons (Li... + +e - -->Li 0 ) and bind to the electrode. Additionally, at multivalent cation-selective electrodes, cations can also act as charge carriers and can be removed from the electrode when a current is applied (M 0 -->M 2+ +2e - For example, as ions enter the compartment, the fluid acts as an ion. (It should be understood that multivalent ions can also be trivalent or have a higher valence, and divalent ions are described here only by way of example.) In summary, in this example, as current is applied to the electrodes, lithium ions are removed from the lithium-rich fluid and exchanged for other multivalent ions.

[0054] However, at a second time point, lithium can be removed from the lithium-selective electrode into a second fluid (e.g., a recovery solution or a lithium-lean fluid). The lithium-lean fluid can be a fluid with a relatively low concentration of lithium (including no lithium). For example, in... Figure 1B In this process, fluid 80 may exist within compartment 20, and current is applied to electrodes 30 and 40. By applying current, lithium is driven out as lithium ions at the lithium-selective electrode (Li). 0 -->Li + +e - At the multivalent cation selective electrode, cations are driven into the electrode (M). 2+ +2e - -->M 0 In this way, lithium ions are driven into a second fluid, for example, by the action of an electric current, thereby exchanging multivalent ions removed from the second fluid.

[0055] Therefore, these electrically driven ion exchange processes collectively cause lithium ions to be removed from a first fluid (e.g., a lithium-rich fluid) to a second fluid (e.g., a lithium-depleted fluid). This can allow for the extraction or purification of lithium from the fluid. However, it should be understood that this disclosure is not limited to the exchange of lithium ions with multivalent cations (e.g., divalent cations). For example, in some embodiments, ions other than lithium (e.g., sodium or potassium ions) can be exchanged. As another example, monovalent ions (e.g., those other than lithium) can be exchanged with lithium ions, for example using a monovalent cation selective electrode as shown in Figure 2. Thus, in this example, cations are removed from the first fluid (e.g., a lithium-rich fluid) to a second fluid (e.g., a lithium-depleted fluid). Figure 2A Remove (M) from the cation-selective electrode 40 0 -->M + +e - ), and drive in Figure 2B In the cation selective electrode 40 (M) + +e - -->M 0 At the lithium selective electrode 30, the lithium reaction is similar to those previously discussed.

[0056] Additionally, in some embodiments, more than two types of ions can be exchanged. As a non-limiting example, in Figure 3, lithium ions can be exchanged for both different cations (e.g., multivalent cations) and anions (e.g., chloride ions), for example, using a cation-selective electrode (for cations) and a non-selective electrode or an anion-selective electrode (for anions). In this figure, electrode 40 may include a first multivalent cation-selective portion 41 and a second non-selective portion 42. In the first portion, when a current is applied, cations can be removed from the electrode at a first time point (in... Figure 3A In the middle, M 0-->M 2+ +2e - ), and at the second time point, it is driven into the electrode (at Figure 3B In the middle, M 2+ +2e - -->M 0 In the second part, anions can be driven into the electrode at the first time point and removed from the electrode at the second time point.

[0057] Therefore, it should be understood that this disclosure is not limited to the apparatus and methods for extracting lithium ions described above, and other embodiments are also possible. For example, various aspects also relate to apparatus and methods for extracting ions, such as using electrochemical ion exchange or other electrically driven ion exchange techniques.

[0058] For example, certain aspects generally relate to apparatus and methods for electrically driven ion exchange. In some embodiments, two or more electrodes connected by electrical pathways may be present in a compartment. The compartment may be used to contain a fluid, such as a fluid containing ions. A voltage source may be used to drive current through the electrodes and the compartment. In the electrical pathway, charge carriers may be electrons; however, in a fluid, the current may be carried by ions within the fluid. Additionally, in some cases, multiple compartments may be used, such as a stack forming the compartments.

[0059] At the electrodes, electrochemical reactions can occur. For example, in the case of cation charge carriers, at one electrode, electrons can flow from the electrical pathway into the electrode and combine with cations to form a neutral material (e.g., a metal) that can bind to the electrode, while at the other electrode, the material can split into cations and electrons, with the cations entering the fluid and the electrons moving into the electrical pathway. In the case of anion charge carriers, at one electrode, electrons can flow from the electrical pathway into the electrode and bind to the neutral material to form anions that can enter the fluid, while at the other electrode, the anions can bind to the electrode, thereby releasing electrons that can enter the electrical pathway.

[0060] In some embodiments, the two electrodes may exist in a common fluid within the compartment, for example, not separated by a membrane or diaphragm that divides the compartment into separate chambers. Thus, in some embodiments, the two electrodes may be in fluid communication with each other within the compartment.

[0061] However, in some embodiments, only specific charge carriers can move from the fluid into the electrode, or vice versa. For example, one or more electrodes can be ion-selective electrodes, such as electrodes that allow one (or a few) ions to enter or leave the electrode. Examples of such ion-selective electrodes, as discussed herein, can include lithium-selective electrodes, monovalent ion-selective electrodes, divalent cation-selective electrodes, multivalent cation-selective electrodes, etc. These electrodes can be used to control the type of ion exchange that occurs when electro-driven ion exchange is used.

[0062] For example, in one set of embodiments, a lithium-selective electrode can be used in conjunction with another electrode (e.g., a divalent cation or other multivalent cation-selective electrode, a monovalent ion-selective electrode of a non-lithium-selective electrode, an anion-selective electrode, a non-selective electrode, etc.). As discussed herein, such electrode combinations (including lithium-selective electrodes) can be used in certain situations to extract lithium from a fluid via ion exchange. For example, in some embodiments, lithium can be bound from a first fluid (e.g., a lithium-rich fluid) to the lithium-selective electrode, and at a second time point, lithium can be removed from the lithium-selective electrode into a second fluid (e.g., a lithium-depleted fluid), thereby causing lithium to be extracted from the first fluid into the second fluid.

[0063] In some embodiments, the binding of lithium or other target ions from a fluid in the compartment to an electrode (e.g., a lithium-selective electrode) and the removal of lithium or other ions from the electrode to the compartment can occur at two different operating times or stages. Thus, at a first time, a first fluid (e.g., a feed solution) may be present in the compartment, and target ions from the first fluid may be bound from the fluid to the target ion-selective electrode, for example, by flowing current through the compartment in a first direction. Because the target ion-selective electrode is selective for target ions, the ions bound to the electrode can be predominantly target ions, as the binding of other ions to the electrode can be suppressed. In contrast, at a second time, a second fluid (e.g., a recovery solution) may be present in the compartment, and target ions from the target ion-selective electrode may be removed from the electrode to the second fluid, for example, by flowing current through the electrode in a second direction (opposite to the first direction). The first and / or second fluids may be introduced into the compartment in various ways, such as as part of a batch operation, or in some cases via continuous flow (e.g., as shown in Figures 1-3). In some cases, this process can be repeated once or multiple times (depending on the application), for example, to extract target ions from a first fluid to a second fluid.

[0064] It should be understood that while many examples herein are described using lithium ions, this disclosure is not limited thereto, and in other respects, apparatuses as described herein may be used to separate target ions other than lithium. Examples of such target ions include sodium, potassium, copper, gold, silver, magnesium, calcium, nickel, manganese, cobalt, chlorides, sulfates, nitrates, hydroxides, heavy metals, transition metals, rare earth elements, lanthanides, actinides, or other ions described below. In some cases, suitable target ion-selective electrodes may be used to allow the separation or extraction of such target ions, as discussed herein. Therefore, more generally, the aspects described herein relate to various apparatuses and methods for extracting ions.

[0065] In one set of embodiments, the apparatus can be used to purify fluids rich in target ions (such as target cations or target anions). As mentioned, in one set of embodiments, the target ion can be lithium. Examples of lithium-rich fluids from which lithium may be extracted include, but are not limited to, water from naturally occurring or artificially produced brine (e.g., salt lake brine, geothermal brine, artificially desalinated brine), water from hydraulic fracturing, brackish water, groundwater, or seawater. In some cases, such water may contain high concentrations of sodium, potassium, calcium, magnesium, and / or other competing ions different from the target ion. As another example, the lithium-rich fluid can be a leachate, such as an acidic or alkaline leachate or other leachate. The leachate can be from, for example, hard rock mining, lithium metal recovery, lithium-ion battery recovery, etc. Examples of lithium-containing hard rocks include spodumene or nepheline, which can be crushed and, in some cases, processed by hydrometallurgical processes to dissolve lithium and other ions in the leachate. Other non-limiting examples include water derived from oil or natural gas extraction (e.g., water produced by hydraulic fracturing), cooling or cleaning water from nuclear power plants, reverse osmosis or other desalination processes, or other water treatment processes.

[0066] However, as mentioned, in other embodiments, other target ions can be extracted instead of lithium or in addition to lithium. For example, the target ion can be a metal ion, such as another dissolved metal cation. Non-limiting examples include sodium, potassium, silver, gold, copper, iron, aluminum, mercury, cadmium, chromium, arsenic, manganese, cobalt, nickel, other transition metals, lanthanum, ytterbium, cerium, neodymium and other lanthanides, yttrium, actinium, thorium, uranium, plutonium and other actinides, etc. In some cases, the target ion can be anion such as chloride ions, sulfate ions, nitrate ions, or hydroxide ions, or ion complexes of the metal cations listed above such as heavy metal oxyanions (e.g., arsenate ions, chromate ions, ferricyanide ions, etc.), which can be extracted using suitable electrodes with selectivity for the target ion as discussed herein. In some cases, more than one target ion can be extracted in the device, for example by using a first electrode in the compartment that is selective for a first target ion and a second electrode in the compartment that is selective for a second target ion, thereby allowing different target ions to be bound (e.g., deposited, embedded, etc.) to and / or removed from different electrodes.

[0067] In some cases, the target ions can be dissolved in an aqueous solution. For example, the aqueous solution can be seawater, brackish water, groundwater, geothermal water, brine, leachate from mining operations, water derived from oil or natural gas extraction, etc. (including any water sources previously described). As a non-limiting example, in one set of embodiments, a first fluid rich in target ions can be obtained by passing water or an aqueous solution through an ore or rock rich in one or more target ions, thereby allowing such ions to leach from the ore or rock. As another example, water or an aqueous solution can be obtained by passing water or an aqueous solution through an electrical component (e.g., a semiconductor chip) to leach such ions. As other examples, water or an aqueous solution can be obtained as a leachate from metal scrap, electronic waste, or battery recycling, etc. In some cases, such processes can be facilitated by raising or lowering the temperature, mechanical operations (crushing, grinding, chopping, pulverizing, etc.).

[0068] In some embodiments, the target ion may be dissolved in a non-aqueous solution. As a non-limiting example, in one set of embodiments, the target ion is lithium, and the first fluid rich in the target ion is a Li-ion battery electrolyte containing an organic solvent such as ethylene carbonate, ethyl methyl carbonate, or dimethyl carbonate, dissolved lithium salt, and possible contaminants. In some embodiments, the organic Li-ion battery electrolyte is obtained from an aged Li-ion battery, and lithium extraction may be performed during battery recycling.

[0069] In some embodiments, lithium (or other target ions) may be present in the fluid at concentrations of at least 0.01 mol%, at least 0.02 mol%, at least 0.03 mol%, at least 0.05 mol%, at least 0.1 mol%, at least 0.2 mol%, at least 0.3 mol%, at least 0.5 mol%, at least 1 mol%, at least 2 mol%, at least 3 mol%, at least 5 mol%, at least 10 mol%, etc., of the target ions. In other embodiments, other concentrations are also possible. In some cases, the concentration of lithium (or other target ions) may be unknown.

[0070] In one set of embodiments, target ions (e.g., lithium, copper, gold, silver, chloride ions, hydroxide ions, etc.) can be extracted into a second fluid or a recovery fluid, such as a fluid that does not contain target ions, or a fluid that is at least relatively poor in or has a lower concentration of target ions compared to a fluid rich in target ions.

[0071] As a non-limiting example, for lithium-ion extraction, the second fluid can be a lithium-lean fluid, such as a fluid with a relatively low concentration of lithium ions (or substantially no lithium ions). For example, a lithium-lean fluid may have a lithium concentration of no more than 0.1 mol%, no more than 0.05 mol%, no more than 0.01 mol%, etc. Non-limiting examples of such fluids include fresh water (e.g., naturally occurring fresh water), purified water, distilled water, desalinated water, municipal water, etc. Other examples of lithium-lean fluids include groundwater, brackish water, partially treated seawater, etc. In some embodiments, the recovery solution may contain relatively low concentrations of other ions. For example, the recovery solution may contain one or more contaminating ions (such as sodium, potassium, etc.) less than 10 g / L, less than 5 g / L, less than 3 g / L, less than 1 g / L, less than 0.5 g / L, less than 0.3 or less than 0.1 g / L, less than 0.05 g / L, less than 0.03 g / L, or less than 0.01 g / L. Other examples of contaminating ions include calcium, magnesium, iron, silicon, or boron.

[0072] The second (or recovered) fluid can then be used for various applications, such as those using extracted lithium or other target ions. The second fluid can have a target ion concentration not exceeding 0.1 mol%, 0.05 mol%, or 0.01 mol%. In some cases, for example, for lithium, lithium can be obtained in the second fluid as a lithium hydroxide solution, lithium chloride solution, lithium carbonate solution, etc. In some embodiments, the second fluid can be used directly as a lithium source for the direct manufacture of lithium batteries, for example, without subsequent processing, purification, crystallization, etc. However, in other cases, the second fluid can be processed, for example, using subsequent steps (such as reverse osmosis, evaporation, precipitation, etc.) to concentrate lithium or other target ions.

[0073] In some respects, the apparatus discussed herein may include one or more compartments that can contain fluid. In some cases, fluid may flow into and / or out of the compartments. The compartments may be formed using metal, plastic, ceramic, or other suitable materials. In some cases, the compartments may be lined or coated with plastic, such as substantially waterproof plastic, hydrophobic plastic, etc. In some embodiments, the compartments may also be filled with and / or supported by porous plastic or other permeable materials, for example, said porous plastic or other permeable materials may facilitate mixing via hydrodynamic dispersion during ion extraction.

[0074] The compartments can be of any size. For example, a compartment can be at least 0.1m in size. 3 At least 0.3m 3 At least 0.5m 3 At least 1m 3 At least 3m 3 At least 5m 3 At least 10m 3 The volume of the compartments is considered. The compartments can also have any suitable shape, including cylindrical or rectangular. However, it should be understood that in some embodiments, non-rectangular stacks or non-rectangular compartments may be used. For example, a stack of compartments may exist where the stack can be cylindrical, for example, having inward or outward radial flow between parallel circular annular electrodes and the membrane (or other diaphragm). This configuration can be useful, for example, for reducing mixing that occurs during ion exchange via hydrodynamic dispersion. In some embodiments, the stack is wound or has a spiral cylindrical shape, optionally having flow normal to or parallel to the electrodes, as described herein. In some embodiments, the flow in such cylindrical stacks may be radially and / or axially oriented. In some embodiments, rectangular or non-rectangular stacks may be vertically oriented, where lighter fluids are introduced above heavier fluids, for example, to reduce mixing by buoyancy-driven convection.

[0075] In some embodiments, the compartments may be open or closed. In some cases, gaskets or spacers may be present. In some embodiments, the compartments may contain inert or porous materials, such as glass fabrics or pads (e.g., coated with PTFE), electrospun or extruded fibrous polymer materials, beds of beads (e.g., glass, ceramics, plastics, etc.). If the compartment is a compartment that allows fluid flow through it, the fluid flow can be in any suitable orientation, such as vertical, horizontal, etc. As an example, in one embodiment, some or all of the compartments in the stack may be vertically oriented, for example, to allow sediment to fall through the compartment for collection.

[0076] In some cases, compartments (e.g., including electrodes, etc.) may define repeating "repeating units" throughout the stack, some or all of which may be substantially identical. Any number of repeating units may be present within the stack. For example, the stack may contain at least 2, at least 4, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 40, at least 50, at least 60, at least 75, at least 100, etc., repeating units. Furthermore, repeating units may extend in two dimensions, or in some cases, in three dimensions. For example, the stack may include multiple repeating units extending in two dimensions. In some cases, repeating units at the ends of the stack may differ from the inner repeating units, for example, ending with different electrode or flow channel geometries. Thus, certain embodiments generally relate to an apparatus comprising multiple compartments or "stacks" of compartments, such as those discussed herein.

[0077] In some cases, fluid may completely fill the compartment, and / or only a portion of the compartment may be filled with fluid. For example, in some cases, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% (by volume) of the compartment may be filled with fluid.

[0078] Depending on various aspects, some or all of the compartments in the device may also house one, two, or more electrodes, such as lithium-selective electrodes or other electrodes including those described herein. Additionally, in some embodiments described in more detail below, the electrodes may be porous, for example comprising particles, fibers, etc., to induce porosity that, in some cases, allows fluid flow through the electrodes. For example, the electrodes may be porous, such as those formed from porous conductive materials as discussed herein.

[0079] Each compartment may independently contain the same or different electrodes. Additionally, in some cases, for example, all electrodes within the stack are compositionally identical except for the presence / absence of any deposited, electroadsorbed, or embedded lithium (or other target ions).

[0080] Additionally, some electrodes within a set of compartments can be connected to each other. For example, a first set of lithium-selective electrodes (and / or other electrodes) can be connected to each other, and / or a second set of non-lithium-ion selective electrodes (and / or other electrodes) can be connected to each other, and the electrode sets can be connected, for example, via electrical pathways.

[0081] A non-limiting example of such a stack is... Figure 6As shown in the figure, the device 10 has three compartments 20, each containing a lithium-selective electrode 30 and a cation-selective electrode 40. In each compartment, fluid 80 flows from left to right, and ions can exchange with the selective electrodes, for example as discussed herein.

[0082] In this example, the electrodes in adjacent compartments have the same type of selectivity, thus creating a stack of “mirror” compartments. However, it should be understood that, although in some embodiments, repeating units within the device may be arranged in a mirror-alternating manner (e.g., as... Figure 6 (As shown in the figure), in other embodiments, other arrangements may also be used.

[0083] In one aspect, the compartment may include one or more ion-selective electrodes. In some embodiments, these ion-selective electrodes may include cation-selective electrodes or anion-selective electrodes, or anion-capturing electrodes. As discussed herein, a variety of ion-selective electrodes may be used in various embodiments. The compartment may contain one, two, or more types of ion-selective electrodes. Additionally, in some embodiments, the compartment may contain any number of electrodes of the same type, such as 1, 2, 3, 4, or more first electrodes and / or 1, 2, 3, 4, or more second electrodes, etc. For example, in various embodiments, the electrodes may include one or more first-type electrodes and / or one or more second-type electrodes, or three or more electrodes of different types may be present in the compartment.

[0084] Non-limiting examples include sodium ion selective electrodes or potassium ion selective electrodes, or other alkali metal ion selective electrodes such as rubidium ion selective electrodes, cesium ion selective electrodes, francium ion selective electrodes, etc. Therefore, in one embodiment, the active material may include a sodium ion intercalating material. Non-limiting examples of sodium ion intercalating materials include sodium manganese oxide (NMO), sodium vanadium oxide (NVO), sodium iron phosphate (NFP), sodium titanium phosphate (NTP), Prussian blue analogues (PBA), Prussian white analogues (PWA), carbon nanomaterials, etc. In one embodiment, the active material may include a potassium ion intercalating material. Non-limiting examples of potassium ion intercalating materials include potassium manganese oxide (KMO), potassium vanadium oxide (KVO), potassium iron phosphate (KFP), potassium vanadium phosphate (KVP), PBA, PWA, graphite, etc.

[0085] Non-limiting examples of sodium or potassium selective intercalation electrode materials include Prussian blue (Fe4[Fe(CN)6]3), Prussian blue analogs, Prussian white (Na2Fe2(CN)6), and Prussian white analogs (e.g., nickel hexacyanoferrate Na2NiFe(CN)6, manganese hexacyanoferrate Na2MnFe(CN)6). Non-limiting examples of sodium ion intercalation materials include sodium manganese oxide (NMO), sodium vanadium oxide (NVO), sodium iron phosphate (NFP), sodium titanium phosphate (NTP), Prussian blue analogs (PBA), Prussian white analogs (PWA), and carbon nanomaterials. In one embodiment, the active material may include a potassium ion intercalation material. Non-limiting examples of potassium ion intercalation materials include potassium manganese oxide (KMO), potassium vanadium oxide (KVO), potassium iron phosphate (KFP), potassium vanadium phosphate (KVP), PBA, PWA, and graphite. In another set of examples, the target ion is a rare earth element (such as lanthanides and actinides), which can be selectively extracted by intercalation, for example, using metal hexacyanoferrate, Prussian blue or Prussian white analogues, or other metal-organic framework (MOF) electrodes. In some cases, rare elements can be separated by size, for example, because smaller, heavier ions can be intercalated more easily. Non-limiting examples of target ions may include metallic lanthanides such as lanthanum, cerium, neodymium, gadolinium, terbium, europium, etc., or metallic actinides such as uranium, plutonium, thorium, etc.

[0086] As a non-limiting example, the compartment can house a lithium-selective electrode, or a non-lithium-selective ion-selective electrode such as a monovalent ion-selective electrode, a divalent cation-selective electrode, a multivalent cation-selective electrode, an anion-selective electrode, etc., as discussed herein. As another example, the compartment can house a sodium-selective electrode, or a non-sodium-selective ion-selective electrode such as a monovalent ion-selective electrode, a divalent cation-selective electrode, a multivalent cation-selective electrode, etc. Therefore, certain embodiments generally relate to a target ion-selective electrode and a non-target ion-selective electrode, such as ion-selective electrodes for various target ions including: copper, gold, silver, magnesium, calcium, nickel, manganese, cobalt, chloride ions, sulfate ions, nitrate ions, hydroxide ions, heavy metals, and other ions (including any of those disclosed herein).

[0087] A non-limiting example of a compartment having more than two electrodes is shown in Figure 5 As shown in the figure, in device 10, compartment 20 houses three lithium-selective flow electrodes 30 and three cation-selective flow electrodes 40. Fluid 80 flows from left to right through compartment 20, passing through each of these flow electrodes. The electrodes are connected together by electrical pathways 50, thereby allowing electrically driven ion exchange to occur as fluid 80 passes through compartment 20.

[0088] In some respects, lithium-selective electrodes can be used. As discussed, a lithium-selective electrode can preferentially allow lithium to bind to (e.g., deposit, intercalate, etc.) or be removed from other coions (e.g., cations or positively charged ions) such as sodium, calcium, magnesium, or other competing ions. The lithium-selective electrode can comprise an active material such as an active battery cathode material. In one set of embodiments, the active material can be a material that is selective in reacting with lithium ions relative to other competing coion pairs. Thus, for example, the active material can be a material that preferentially reacts with lithium ions in solution, for example, such that lithium ions can bind to the electrode as a result of this reaction. Non-limiting examples of materials that can be used in lithium-selective electrodes include lithium iron phosphate, lithium titanium phosphate, lithium manganese oxide, or other materials (as described herein). In some embodiments, binding can occur by ion intercalation, electroadsorption, electrodeposition, etc., and combinations of these and / or other processes. In some cases, this reaction can be reversible, for example, such that the bound lithium can be released from the active material to enter the solution as lithium ions.

[0089] In some cases, the active material can be a material that forms a lithium salt, a reduced lithium metal, and / or a material that intercalates lithium ions when compensating for electron reduction in the host material. The active material can be, for example, a lithium-ion battery active material, such as a lithium-ion intercalation material. Additionally, in some cases, more than one such active material may be present, including any one or more of the active materials described herein, and / or other active materials.

[0090] For example, in one embodiment, the active material may include lithium metal phosphate LiMePO4, wherein Me may be a transition metal such as iron (e.g., lithium iron phosphate LiFePO4 or LFP), titanium (e.g., lithium titanium phosphate LiTi2(PO4)3 or LTP), manganese, nickel, cobalt, etc., or a mixture of transition metals such as manganese, iron, cobalt, nickel, etc. (e.g., lithium manganese iron phosphate LiMn). x Fe 1-x PO4 or LMFP). In some cases, more than one such metal may be present, including these and / or other suitable metals. For example, the active material may include blends of LTP and LFP, compositions containing lithium iron phosphate, other blends, etc. In some embodiments, a smaller amount of a metal (e.g., a transition metal such as manganese or nickel) may be present, for example, in an active material (e.g., lithium manganese nickel phosphate, LiFe). 1-x-y Mn x Ni y PO4, where x and y are each independently less than 1).

[0091] In some cases, the active material may include lithium transition metal oxide LiMeO2, where Me may be a transition metal. Non-limiting examples include manganese (e.g., lithium manganese oxide LiMnO2 or LMO), nickel (e.g., lithium nickel oxide LiNiO2 or LNO), cobalt (e.g., lithium cobalt oxide LiCoO2 or LCO), etc. In some embodiments, more than one transition metal may be present, for example, as a combination or stoichiometric blend. As a non-limiting example, the active material may include a combination of LiMnO2 and LiNiO2, or contain Li(MnO2)2, LiNiO2, etc. x Ni 1-x Compositions of O2, etc.

[0092] In another example, the active material may include lithium titanate Li₂TiO₃ and / or Li₄Ti₅O₃. 12 (LTO), optionally having a coating such as LiTiO2 or other coatings (as described herein). Other non-limiting examples of lithium-ion intercalation materials include nickel manganese cobalt oxide (NMC) or nickel cobalt aluminum oxide (NCA).

[0093] In yet another example, the active material can be a solid metal. Examples include, but are not limited to, lithium metal, which can be coated with a lithium-selective solid electrolyte membrane material such as lithium superion conductor (LISICON). In some embodiments, a buffer coating such as lithium phosphorus oxynitride (LiPON) can be applied to avoid chemical reduction of Ti(IV) in LISICON or other degradation phenomena upon contact with aqueous brine. Other non-limiting examples of membrane materials include lithium aluminum titanium phosphate, lithium superion conductor, LiPON, lithium lanthanum zirconium oxide, solid polymer electrolytes, etc.

[0094] In another example, the active material may include lithium-ion intercalating materials. Non-limiting examples of lithium-ion intercalating materials include lithium titanium phosphate (LTP), lithium manganese oxide (LMO), nickel manganese cobalt oxide (NMC), nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium titanium oxide (LTO), disordered rock salt (DRX), graphite, graphene oxide, hard carbon, carbon ionomer composites, functionalized carbon, etc.

[0095] However, in one set of embodiments, for example if the target ion to be extracted is not lithium, an electrode selective for other target ions (e.g., cations other than lithium ions, such as sodium, potassium, hydrogen, etc.) can be used. In some embodiments, the electrode may comprise an active material that can be used for selectively intercalating sodium or potassium, such as Prussian blue (Fe4[Fe(CN)6]3), Prussian blue analogues (e.g., nickel hexacyanoferrate Ni2FE(CN)6), sodium manganese oxide (Na2Mn5O)10 Titanium disulfide (TiS2), sodium chromium oxide, sodium cobalt oxide, sodium manganese oxide, sodium cobalt phosphate, sodium nickel phosphate, sodium iron phosphate, potassium cobalt oxide, potassium manganese oxide, potassium iron phosphate, potassium vanadium oxide, potassium vanadium phosphate, Prussian white (e.g., Prussian white potassium or KPW), Prussian white analogues (e.g., nickel hexacyanoferrate Na2NiFe(CN)6, manganese hexacyanoferrate Na2MnFe(CN)6), etc.). In another set of embodiments, the electrode can be relative to monovalent ions (such as Na... + Li + and K + For multivalent target ions (such as Mg) 2+ or Ca 2+ These materials exhibit selectivity, for example, due to the high chemical surface charge in microporous metal electrodes. Non-limiting examples of such multivalent ion-selective electrodes include sulfonated porous carbon, vanadium oxides, Prussian blue analogues, molybdenum sulfides, molybdenum oxides, manganese oxides, manganese / iron / cobalt silicates, vanadium phosphate, Mg metal, Ca metal, Mg / Ca alloys, etc. In some cases, one or more of these materials may be present, for example, as intercalators. In yet another embodiment, the active material may include metal oxides, metal phosphates, metal-organic frameworks, conjugated polymers, and / or carbonaceous materials, etc.

[0096] In one set of embodiments, the active material may be present in the electrode at a concentration of at least 1 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, etc. In some cases, the active material may be present in a concentration not exceeding 95 wt%, not exceeding 90 wt%, not exceeding 85 wt%, not exceeding 80 wt%, not exceeding 75 wt%, not exceeding 70 wt%, not exceeding 65 wt%, not exceeding 60 wt%, not exceeding 55 wt%, not exceeding 50 wt%, not exceeding 45 wt%, not exceeding 40 wt%, not exceeding 35 wt%, not exceeding 30 wt%, not exceeding 25 wt%, not exceeding 20 wt%, not exceeding 15 wt%, etc. Any combination of these is also possible. For example, the active material can be present at concentrations between 70 wt% and 90 wt%, between 30 wt% and 50 wt%, between 20 wt% and 45 wt%, etc.

[0097] In some embodiments, the active material can be at a concentration of at least 1 mg / cm³. 2The surface exists within the electrode. In some cases, the active material can be present at a concentration of at least 2 mg / cm³. 2 At least 3mg / cm 2 At least 5mg / cm 2 At least 10 mg / cm 2 At least 15 mg / cm 2 At least 20 mg / cm 2 At least 25 mg / cm 2 At least 30 mg / cm 2 At least 35mg / cm 2 At least 40 mg / cm 2 At least 45 mg / cm 2 At least 50 mg / cm 2 At least 55mg / cm 2 At least 60mg / cm 2 At least 65mg / cm 2 At least 70mg / cm 2 At least 75mg / cm 2 At least 80mg / cm 2 At least 85 mg / cm 2 At least 90mg / cm 2 At least 100 mg / cm 2 At least 110 mg / cm 2 At least 120 mg / cm 2 At least 150 mg / cm 2 At least 200 mg / cm 2 The presence of these substances is also present. In some cases, the active material can be present at a concentration not exceeding 200 mg / cm³. 2 Not exceeding 150 mg / cm 2 Not exceeding 120 mg / cm 2 Not exceeding 110 mg / cm 2 Not exceeding 100 mg / cm 2 Not exceeding 90mg / cm 2 Not exceeding 85mg / cm 2 Not exceeding 80mg / cm 2 Not exceeding 75mg / cm 2 Not exceeding 70mg / cm 2 Not exceeding 65mg / cm 2 Not exceeding 60mg / cm 2 Not exceeding 55mg / cm 2 Not exceeding 50 mg / cm 2 Not exceeding 45mg / cm 2 Not exceeding 40 mg / cm2 Not exceeding 35mg / cm 2 Not exceeding 30mg / cm 2 Not exceeding 25 mg / cm 2 Not exceeding 20 mg / cm 2 Not exceeding 15 mg / cm 2 Not exceeding 10 mg / cm 2 Not exceeding 5mg / cm 2 Not exceeding 3mg / cm 2 Not exceeding 2mg / cm 2 Not exceeding 1 mg / cm 2 Furthermore, any combination of these ranges is also possible.

[0098] In some cases, the active material may exhibit contact angles of at least 60°, at least 70°, at least 75°, at least 80°, at least 85°, at least 90°, at least 95°, at least 100°, at least 105°, at least 110°, at least 115°, at least 120°, etc. In some cases, the electrode or other component may exhibit contact angles not exceeding 140°, not exceeding 135°, not exceeding 130°, not exceeding 125°, not exceeding 120°, not exceeding 115°, not exceeding 110°, not exceeding 105°, not exceeding 100°, etc. In some cases, the contact angle may be any combination of these. For example, the active material or other component may have contact angles between 75° and 90°, between 70° and 100°, between 80° and 100°, etc.

[0099] Additionally, in some respects, the compartment may include one or more divalent or other multivalent cation-selective electrodes. Examples of divalent ions (+2 charge) include Ca2+. 2+ Mg 2+ Ni 2+ Co 2+、 Zn 2+ Cu 2+ Mn 2+ Certain lanthanides or actinides, etc. However, other higher charges are also possible, such as ions with a +3 charge, like Fe. 3+ Al 3+ Co 3+Certain lanthanide or actinide elements, etc. Specific, non-limiting examples of multivalent cation selective electrodes include, but are not limited to, Mg selective electrodes, Mn selective electrodes, Ni selective electrodes, etc. In some cases, such ion selective electrodes can be fabricated in a manner similar to lithium selective electrodes, as discussed herein. In some embodiments, the ion selective electrode can be a divalent or other multivalent selective electrode. A divalent or other multivalent selective electrode can have relative selectivity only for monovalent ions. This can be achieved, for example, by functionalizing the electrode to make the surface charge relatively dense and negatively charged, for example, to induce a preference for ions with more positive charges than for ions with fewer positive charges.

[0100] In some cases, cation-selective electrodes are carbon-based electrodes. For example, carbon-based electrodes can be formed from carbon-based materials such as activated carbon, carbon nanotubes, graphene, carbon aerogel, graphitic carbon, carbon black, graphene oxide, Vulcan carbon, coke, carbon nanotubes, etc. In some cases, the electrode can be porous, for example, formed from porous conductive materials as discussed herein. Fluids can also flow around the current and / or flow through the electrode (e.g., using a flow-through electrode).

[0101] In some embodiments, the cation-selective electrode can be functionalized to enhance cation selectivity. In some cases, the surface can be functionalized using functionalizing agents that can react with the surface to form surface groups. For example, the electrode can be enhanced with surface groups such as carboxylic acids, sulfonic acids, phosphoric acids, etc. In some cases, the cation-selective electrode can be pre-charged in situ or ex-situ.

[0102] Additionally, in some cases, the electrode may include portions with different selectivities. For example, the electrode may include a first portion and a second portion, wherein the first portion is functionalized (e.g., as discussed herein), while the second portion is unfunctionalized or functionalized with different functional groups. For example, the first portion may be functionalized as a divalent or other multivalent cation-selective electrode, while the second portion may be non-selective to ions and / or may be functionalized to be selective to ions different from those of the first portion. In some cases, for example, the second portion may be non-selective. In some embodiments, the second electrode may act as a more general cation electrode or an anion electrode. Furthermore, the first and second portions may be in physical contact with each other or, in some cases, separate.

[0103] In one embodiment, as a non-limiting example, the electrode may be functionalized for a portion of its electrode region to enhance the selectivity for divalent or other multivalent cations with surface groups, while the remaining portion of the electrode remains unfunctionalized and largely nonselective. This segmentation can occur within a single continuous electrode, between layers of material forming the electrode, or between individual electrodes placed in the same compartment or between adjacent compartments, etc.

[0104] Additionally, depending on certain aspects, the electrodes (such as those discussed herein, including lithium-selective electrodes and / or divalent or other multivalent cation-selective electrodes) can independently have any shape or size, and electrodes in different compartments can independently have the same or different shapes or sizes. For example, electrodes can be rectangular, cylindrical, annular, or spherical, or have other shapes (including regular or irregular shapes). In some cases, the electrodes can have a maximum dimension of at least 10 mm, at least 20 mm, at least 30 mm, at least 50 mm, at least 100 mm, at least 200 mm, at least 300 mm, at least 500 mm, at least 1000 mm, etc. In some embodiments, the electrodes can have a maximum dimension of no more than 1000 mm, no more than 500 mm, no more than 300 mm, no more than 200 mm, no more than 100 mm, no more than 50 mm, no more than 30 mm, no more than 20 mm, no more than 10 mm, no more than 5 mm, no more than 3 mm, no more than 2 mm, no more than 1 mm, no more than 5 mm, no more than 3 mm, no more than 2 mm, no more than 1 mm, etc. In yet other embodiments, any combination of these ranges is also possible. For example, the electrode can have a maximum dimension between 300mm and 500mm, between 500mm and 1000mm, between 10mm and 50mm, etc.

[0105] A compartment may contain only a single electrode, or in some cases more than one electrode. If more than one electrode is present, the electrodes may independently have the same or different sizes, shapes, compositions, etc. Additionally, as discussed herein, some or all compartments within the stack may independently house one or more electrodes, which may independently have the same or different sizes, shapes, compositions, etc. As an example, in some embodiments, at least 50%, at least 75%, at least 80%, or at least 90% of the electrodes within the stack may be compositionally identical, except for the presence / absence of any bound lithium. In some cases, the electrodes within the stack may be connected via electrical pathways in any suitable arrangement (e.g., in any suitable configuration, such as series, parallel, or other arrangements). In some embodiments, different electrode groups may exist within the stack (e.g., a first group of electrodes and a second group of electrodes), and the electrodes within a group may be independently connected to each other in the same or different configurations (e.g., series, parallel, or other configurations).

[0106] In one set of embodiments, the electrode may include a coating. In some embodiments, the coating may partially or completely surround the active material, and / or the active material may be present in the coating (e.g., as a component of the coating). In some cases, one or more coatings may be present. However, it should also be understood that in some cases, a coating may not be present. Depending on the embodiment, the coating may provide a variety of functions. In some cases, the coating may be used to enhance wettability, increase ionic or electronic conductivity, improve electrochemical stability, etc. For example, in one embodiment, the coating may contain a lithium-selective material that can provide additional lithium selectivity relative to a competing coion (such as sodium). Other ion-selective (e.g., cation-selective) materials may also be used in some embodiments, for example for target ions other than lithium. As another example, the coating may include a hydrophilic coating that can improve the wettability of the electrode. In other embodiments, the coating may contain lyotropic ions, for example, to control scaling, wettability, precipitation, and macromolecular interactions.

[0107] Non-limiting examples of coating materials include lithium titanium oxide (LiTiO2) or polydopamine. Further non-limiting examples of coating materials include carbon (e.g., graphitic carbon, carbon black, graphene oxide, Vulcan carbon, coke, carbon nanotubes, etc.) or conductive polymers (e.g., polypyrrole (PPy), polyethylene oxide (PEO), etc.). Another example includes ceramics. For example, coating materials may include one or more oxides of aluminum (i.e., alumina), silicon, zirconium (i.e., zirconium oxide), niobium, etc. Other examples of ceramics include titanium dioxide or phosphate or borosilicate glasses. In some cases, such coating materials can slow down or block the transfer of electrons, metal ions, and / or oxygen.

[0108] The coating (if present) can have any thickness on the electrode. For example, the coating can have an average thickness of at least 0.1 mm, at least 0.2 mm, at least 0.3 mm, at least 0.5 mm, at least 1 mm, at least 2 mm, at least 3 mm, at least 5 mm, at least 10 mm, at least 20 mm, at least 30 mm, at least 50 mm, at least 100 mm, etc., on the electrode. Additionally, the coating can cover all or part of the electrode. For example, in various embodiments, the coating can cover at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, etc., of the electrode.

[0109] In one set of embodiments, the electrode may be porous, for example, formed of a porous conductive material. For example, the electrode may have a porosity that allows liquids to enter and / or pass through the pores, for example, in the normal or transverse direction of the current. Thus, porosity can allow liquids to enter the electrode, thereby allowing ions to bind and / or migrate out of the electrode, for example, due to the increased available surface area. For example, porosity can allow ions to rapidly transfer mass deep into the electrode material.

[0110] In some cases, the electrode may have a porosity of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and / or not exceeding 90%, not exceeding 85%, not exceeding 80%, not exceeding 75%, not exceeding 70%, not exceeding 65%, not exceeding 60%, not exceeding 55%, not exceeding 50%, not exceeding 45%, not exceeding 40%, not exceeding 35%, not exceeding 30%, not exceeding 25%, not exceeding 20%, not exceeding 15%, not exceeding 10%, not exceeding 5%, etc., as determined by the volume fraction of the material forming the electrode. For example, the electrode may have a volumetric porosity between 20% and 80%, between 20% and 25%, between 10% and 30%, between 35% and 45%, between 30% and 40%, between 25% and 70%, etc. Additionally, in some cases, the pores may have an average cross-sectional size less than 1 mm, less than 300 μm, less than 100 μm, less than 30 μm, less than 10 μm, less than 3 μm, less than 1 μm, less than 300 nm, less than 100 nm, less than 30 nm, or less than 10 nm, etc. Porosity can be determined using standard porosity measurement techniques known to those skilled in the art (e.g., mercury porosimetry, circulating porosimetry, gas absorption techniques, etc.).

[0111] The porosity within an electrode can be configured in various ways. For example, an electrode may include one or more channels through which fluids can flow (e.g., “flow-through” channels). See, for example, U.S. Patent Application Serial No. 63 / 513,538, filed July 13, 2023, entitled “Flow Systems and Methods for Membraneless Separation,” the entire contents of which are incorporated herein by reference. As another example, an electrode may be made of, for example, particles, fibers (which may be woven or nonwoven), and / or other materials filled into the electrode. For example, particles or fibers of active materials (e.g., as discussed herein), inert materials, conductive materials, etc., may be filled together to form an electrode. Due to the shape of the particles, fibers, or other materials, spaces or pores may exist within the electrode through which fluids can flow.

[0112] Examples of inert materials include, but are not limited to, glass (e.g., phosphate glass), plastics, ceramics, etc.

[0113] In some cases, one or more pore-forming agents can be used to form the electrode, which can increase the electrode's porosity. In other cases, the pore-forming agent can be removed, thereby increasing the electrode's porosity. For example, the electrode can be manufactured using a pore-forming agent such as polyethylene glycol (PEG), for example, PEG-6000. Other examples of pore-forming agents include, but are not limited to, sucrose, ammonium carbonate, sodium chloride, or other salts. Further examples of pore-forming agents include chloride salts, sulfates, silica, carbonates, polystyrene, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polymethyl methacrylate (PMA), polyacrylic acid (PAA), etc. The pore-forming agent can then be removed, for example, by heating the electrode to oxidize the pore-forming agent, or by adding water to dissolve the pore-forming agent. Other methods for introducing porosity into the electrode include laser ablation, additive manufacturing, mechanical patterning, etc.

[0114] Non-limiting examples of embodiments accommodating flow-through electrodes are shown in Figure 7 As shown in the figure, in device 10, compartment 20 houses two lithium-selective electrodes 30, a cation-selective electrode 40, and a non-selective electrode 44. Both the cation-selective electrode 40 and the non-selective electrode 44 are flow-through electrodes, which allows fluid 80 to flow from inlet 90 through compartment 20 into the first compartment 91, through the electrode into the second compartment 92, and then to outlet 95. Although this example does not show a flow-through lithium-selective electrode, it should be understood that this example is not limiting, and in other embodiments, the lithium-selective electrode (or another electrode) may be a flow-through electrode, and / or other electrodes need not be flow-through electrodes.

[0115] In one set of embodiments, the electrode may contain additives (such as conductive additives) that can be used to increase the conductivity of the electrode. Non-limiting examples of additives include carbon (e.g., graphitic carbon, carbon black, graphene oxide, Vulcan carbon, coke, etc.), metals (e.g., gold, silver, copper, etc.), etc. Additionally, in some embodiments, more than one additive may be present in the electrode.

[0116] Examples of conductive materials include, but are not limited to, carbon particles, such as coke particles, carbon black, Vulcan carbon particles, etc. In one set of embodiments, the conductive material may include a capacitive material. Non-limiting examples of conductive materials include graphite, titanium, activated carbon, sulfonated carbon, etc. As another example, the conductive material may include a metal (e.g., present as a metal powder). Non-limiting examples include titanium, platinum, silver, zirconium, tin, copper, gold, zinc, stainless steel. As yet another example, the conductive material includes glass microspheres, such as metal-coated glass microspheres (as described herein). In yet another example, the conductive material may include a conductive carbon material. Non-limiting examples include carbon black, carbon nanotubes, graphene, graphene oxide, etc. Other examples include conductive polymers. Non-limiting examples of conductive polymers include poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS), polypyrrole, polythiophene, polyaniline (PANI), polythiophene, etc. Still other examples of conductive materials include conductive ceramics. Non-limiting examples of conductive ceramics include indium tin oxide (ITO), niobium titanium oxide (NTO), etc. Additionally, one or more conductive materials (including any conductive materials described herein) may be present.

[0117] In one set of embodiments, the conductive material may be present in the electrode at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, etc. In some cases, the conductive material may be present at no more than 80 wt%, no more than 75 wt%, no more than 70 wt%, no more than 65 wt%, no more than 60 wt%, no more than 55 wt%, no more than 50 wt%, no more than 45 wt%, no more than 40 wt%, no more than 35 wt%, no more than 30 wt%, no more than 25 wt%, no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, no more than 5 wt%, no more than 1 wt%, etc. Any combination of these is also possible. For example, conductive materials can exist at concentrations between 5 wt% and 80 wt%, between 30 wt% and 50 wt%, between 20 wt% and 45 wt%, etc.

[0118] In some cases, conductive materials may exhibit contact angles of at least 60°, at least 70°, at least 75°, at least 80°, at least 85°, at least 90°, at least 95°, at least 100°, at least 105°, at least 110°, at least 115°, at least 120°, etc. In some cases, electrodes or other components may exhibit contact angles not exceeding 140°, not exceeding 135°, not exceeding 130°, not exceeding 125°, not exceeding 120°, not exceeding 115°, not exceeding 110°, not exceeding 105°, not exceeding 100°, etc. In some cases, the contact angle may be any combination of these. For example, electrodes or other components may have contact angles between 90° and 125°, between 85° and 120°, between 80° and 100°, etc.

[0119] In some embodiments, the electrode may contain an ion-conducting additive. In some embodiments, this can improve ion transport through the electrode. In some embodiments, the ion-conducting additive may include perfluorinated hydrocarbon polymers (trade names Nafion, Aquivion, etc.) linked to sulfonate groups, alkali metal salts of polystyrene sulfonates, alkali metal salts of sulfonated poly(ether-ether ketone) (SPEEK), alkali metal salts of polyethylene sulfonates, hydrocarbon polymers with fully alkylated ammonium groups, hydrocarbon polymers with fully alkylated phosphonium groups, etc.

[0120] In some embodiments, the additive may be present in the electrode at a concentration of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%. In some embodiments, the additive may be present in a concentration of no more than 90 wt%, no more than 85 wt%, no more than 80 wt%, no more than 75 wt%, no more than 70 wt%, no more than 65 wt%, no more than 60 wt%, no more than 55 wt%, no more than 50 wt%, no more than 45 wt%, no more than 40 wt%, no more than 35 wt%, no more than 30 wt%, no more than 25 wt%, no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, no more than 5 wt%, no more than 1 wt%. In some embodiments, combinations of these are also possible. For example, one or more additives may be present in amounts between 30 wt% and 50 wt%, between 60 wt% and 80 wt%, between 5 wt% and 80 wt%, between 10 wt% and 20 wt%, etc.

[0121] In some embodiments, the electrode may contain a mixed ion-electron conductivity (MIEC) additive. In some embodiments, this can improve the transport of both ions and electrons through the electrode. Examples of MIEC additives include, but are not limited to, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), or polystyrene sulfonate (cationically conductive) with polyaniline, polythiophene, polypyrrole, graphite, graphite oxide, carbon-coated garnet, non-stoichiometric oxides and perovskites, strontium titanate, titanium dioxide, cerium dioxide, etc.

[0122] In some embodiments, the additive may be present in the electrode at a concentration of at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%. In some embodiments, the additive may be present in a concentration of no more than 90 wt%, no more than 85 wt%, no more than 80 wt%, no more than 75 wt%, no more than 70 wt%, no more than 65 wt%, no more than 60 wt%, no more than 55 wt%, no more than 50 wt%, no more than 45 wt%, no more than 40 wt%, no more than 35 wt%, no more than 30 wt%, no more than 25 wt%, no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, no more than 5 wt%, no more than 1 wt%. In some embodiments, combinations of these are also possible. For example, one or more additives may be present in amounts between 30 wt% and 50 wt%, between 60 wt% and 80 wt%, between 5 wt% and 80 wt%, between 10 wt% and 20 wt%, etc.

[0123] Additionally, in one set of embodiments, the electrode may include a binder. The binder can facilitate electrode formation, for example, by bonding components (such as active materials) together with other components (if present) (such as additives, particles, fibers, conductive materials, inert materials, particles, or fibers, etc.). In some embodiments, the binder may include one or more polymers. Non-limiting examples of polymers include polyvinylidene fluoride (PVDF), polypyrrole (PPy), polyethylene oxide (PEO), etc. In some cases, the polymer may be a hydrophobic polymer, such as a hydrophobic polymer exhibiting an air-water contact angle or other contact angle (as described herein) greater than 90°, greater than 100°, greater than 110°, greater than 120°, greater than 130°, etc. Further non-limiting examples of hydrophobic polymers include polytetrafluoroethylene (PTFE), fluoroethers, fluorinated ethylene propylene (FEP), silicone, polyvinylidene fluoride (PVDF), polypropylene, polystyrene, polyethylene terephthalate (PET), etc. In some embodiments, silicone or silicone polymers may be used. For example, the silicone polymer may be a cross-linked silicone polymer, and / or the silicone or silicone polymer may be infused with silicone oil.

[0124] In one set of embodiments, the binder may be present in the electrode at least 1 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, etc. In some cases, the binder may be present at no more than 80 wt%, no more than 75 wt%, no more than 70 wt%, no more than 65 wt%, no more than 60 wt%, no more than 55 wt%, no more than 50 wt%, no more than 45 wt%, no more than 40 wt%, no more than 35 wt%, no more than 30 wt%, no more than 25 wt%, no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, no more than 5 wt%, no more than 1 wt%, etc. Any combination of these is also possible. For example, the adhesive can be present at concentrations between 5 wt% and 80 wt%, between 30 wt% and 50 wt%, between 20 wt% and 45 wt%, etc.

[0125] In some cases, the adhesive may exhibit contact angles of at least 30°, at least 40°, at least 50°, at least 60°, at least 70°, at least 75°, at least 80°, at least 85°, at least 90°, at least 95°, at least 100°, at least 105°, at least 110°, at least 115°, at least 120°, etc. (determined using surfaces in air and pure water). In some cases, the adhesive may exhibit contact angles not exceeding 120°, not exceeding 115°, not exceeding 110°, not exceeding 105°, not exceeding 100°, not exceeding 95°, not exceeding 90°, not exceeding 85°, not exceeding 80°, not exceeding 75°, not exceeding 70°, not exceeding 60°, not exceeding 50°, not exceeding 40°, etc. In some cases, the adhesive may exhibit contact angles as any combination of these.

[0126] In one aspect, the electrodes can be in contact with the current collector. The current collector can collect electric current (electrons) that can flow from a first set of electrodes within the device to a second set of electrodes, or vice versa, as discussed herein. In some embodiments, the current collector may comprise a material that is relatively inert to the fluid and / or the active material. Non-limiting examples of materials used as current collectors include carbon, graphite, titanium, aluminum, copper, stainless steel, platinum, metal / polymer composites, graphite / polymer composites, etc.

[0127] In some embodiments, the current collector may be in the form of a mesh or fiber, for example, for use in porous electrodes and / or flow-through electrodes. For example, the current collector may include a metal mesh, carbon cloth, etc. In some cases, the current collector may also be a solid material.

[0128] In some respects, the compartments can operate in an alternating or "rocking chair" manner, wherein at a first time point, a first fluid (e.g., from a first fluid source) is present in the compartment, and at a second time point, a second fluid (e.g., from a second fluid source) is present in the compartment. For example, the first fluid may be a lithium-rich fluid or a fluid rich in another target ion, while the second fluid may be a lithium-poor fluid or a fluid poor in the target ion.

[0129] The compartment can be operated in any suitable manner, such as as a batch, semi-batch, or continuous process. For example, in a batch operation, the compartment can be partially or completely filled with a first fluid at a first time point, and then the first fluid can be removed and the compartment filled with a second fluid at a second time point. In contrast, in a continuous operation, fluid can be continuously passed through the compartment, for example, while an electric current is applied to the electrodes. Combinations of these methods can also be used in other embodiments, such as allowing the first fluid to be statically contained within the compartment at a first time point, while a second fluid continuously flows through the compartment at a second time point.

[0130] In some embodiments, the same compartment can be used at different times during use or operation to bind lithium (or other target ions) to and remove lithium (or other target ions) from the electrode. For example, at a first time point, lithium-rich fluid can pass through the compartment and lithium is bound to the electrode, and at a second time point, lithium-depleted fluid can pass through the compartment and lithium is removed from the electrode. In other embodiments, other target ions besides lithium, or instead of lithium, can be bound or removed.

[0131] In some embodiments, the switching between the first fluid and the second fluid in the compartment may occur on a periodic or regular basis, or the repetition may occur on an aperiodic or irregular basis. The second fluid may be used for a variety of purposes, such as as a lithium source for the production of lithium batteries, or for other applications (as described herein). Additionally, in some embodiments, the compartment may be “flushed” between switching, for example with a different fluid and / or by initially draining some fluid from the compartment after the switching occurs.

[0132] In some cases, the flushing or rinsing fluid can be selected to be the same as the fluid recently introduced into the compartment, but in other cases, the fluid can be different. For example, after lithium (or other target ions) is released from the contact electrode, an additional recovery fluid can be used to flush the recovery compartment. The duration and flow rate of the flushing step can be controlled to increase the recovery rate of additional target ions while minimizing dilution of the recovery fluid.

[0133] In one set of embodiments, fluid mixing can be reduced whenever a fluid is switched in a given compartment. Without being bound by any theory, fluid mixing can be dominated by convection and associated hydrodynamic dispersion. In some embodiments, a converging flow field, for example, with a radially inward flow geometry, can be designed to limit the total volume of the mixing zone. As a non-limiting example, in some cases, the mixing volume between two miscible fluids in contact with each other can be estimated as the product of the existing cross-sectional area between the two fluids and the thickness of the mixing zone, approximately sqrt(2Kt), where t is the residence time and K is the hydrodynamic dispersion coefficient of the channel. Enhanced mixing in turbulence can be avoided by maintaining a small Reynolds number in open compartments. Hydrodynamic dispersion can be limited, for example, by reducing the flow rate during fluid switching, by altering the microstructure to reduce the size or thickness of channels and / or pores and / or rings in the pore network, etc.

[0134] As mentioned, the timing of fluid switching can be fixed or variable. For example, in one set of embodiments, the fluid switches at a fixed period or frequency. In another set of embodiments, the timing of fluid switching can vary, for example, in a regular or irregular pattern. In some cases, the timing of fluid switching can depend on the conditions within the compartment. For example, in some embodiments, fluid switching can occur when a certain amount of lithium (or other target ions) has been bound, or when a certain current is reached in the electron flow between the compartment groups.

[0135] In one set of embodiments, a flow switching element is used to control the fluid. The flow switching element can be configured and arranged to direct a first fluid from a first fluid source to a first outlet and a second fluid from a second fluid source to a second outlet at a first time, and to direct the first fluid from the first fluid source to the second outlet and the second fluid from the second fluid source to the first outlet at a second time. In some cases, the flow switching element can direct the first fluid from the first fluid source to the inlet of a first compartment (or a first common inlet of a first group of compartments) at a first time point and to direct the second fluid from the second fluid source to the inlet of a second compartment (or a second common inlet of a second group of compartments), and to direct the first fluid from the first fluid source to the inlet of the second compartment (or a second common inlet of a second group of compartments) at a second time point and to direct the second fluid from the second fluid source to the inlet of the first compartment (or a first common inlet of a first group of compartments) at a second time point. Additionally, in some cases, the flow switching element can guide a first fluid from a first fluid source to the inlet of a first compartment (or the first common inlet of a first group of compartments) and the inlet of a second compartment (or the second common inlet of a second group of compartments) at a first time point, and guide a second fluid from a second fluid source to the inlet of the first compartment (or the first common inlet of the first group of compartments) and the inlet of the second compartment (or the second common inlet of the second group of compartments) at a second time point. The flow switching element can be a single component or comprise multiple components that together form the flow switching element.

[0136] In some cases, flow switching elements can also allow the introduction of other fluids into, for example, one or both outlets. For instance, between switching, there may be a period of time during which buffer solutions or flushing fluids can be added, for example, to separate the first fluid from the second fluid (or vice versa), to allow for cleaning of the compartment, etc.

[0137] As another non-limiting example, the flow switching element can be configured and arranged to allow a first fluid to flow into some or all of the compartments of the device at a first time, and to allow a second fluid to flow into some or all of the compartments of the device at a second time. For example, in one set of embodiments, the flow switching element can be configured and arranged to allow a lithium-rich (or other target ion-rich) fluid to flow into a compartment at a first time, and to allow a flushing fluid to flow into a compartment at a second time. At a third time, the flow switching element can be configured and arranged to allow a third fluid to flow into a compartment, such as a lithium-depleted (or other target ion-depleted) fluid. In some cases, some or all of the compartments of the device may have the same fluid, for example, as controlled by the flow switching element.

[0138] In some aspects, some or all of the electrodes within the compartment may be connected to each other, for example, via one or more electrical pathways. In some embodiments, a voltage may be applied to the electrodes, for example, generating a potential in the electrical pathway connecting the electrodes. In some cases, this potential may be used to drive the process, for example, to enable faster or better extraction of the target ions. The potential may be applied from an external voltage source, such as a battery, municipal power, or other power source (e.g., fossil fuel or renewable power source).

[0139] However, it should also be understood that in some cases, a potential can be applied to delay the process, which may result in slower or less efficient extraction of lithium or other target ions. This can be useful in some situations, such as for controlling the rate at which target ions bind to or migrate from the electrode.

[0140] In some aspects, the second fluid may contain lithium ions that pair with anions (such as chloride ions and / or sulfate ions) from the first fluid. In some embodiments, the second fluid may contain a reagent that allows the device to directly generate lithium hydroxide, lithium carbonate, or other lithium chemicals.

[0141] For example, in some cases, the second fluid may contain one or more reagents that can be used to precipitate the target ion. For example, if the target ion is lithium, the second fluid (e.g., a lithium-depleted fluid) may contain hydroxides (such as sodium hydroxide (NaOH) or potassium hydroxide (KOH)) that can cause lithium to precipitate as lithium hydroxide (LiOH). The second fluid may have a relatively high pH, ​​such as at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, etc. In some cases, LiOH may precipitate at the outlet or outlet channel of the compartment.

[0142] As another example, in one embodiment, sodium carbonate (soda ash) can be used to precipitate lithium to prepare Li₂CO₃. In another embodiment, sodium hydroxide can be used to precipitate lithium to prepare LiOH. As other examples, sodium carbonate can be used to precipitate certain divalent or polyvalents, such as Mg or Ca, to form MgCO₃ or CaCO₃, respectively; CaCO₃ (lime) can be used to precipitate magnesium to prepare MgCO₃; or sodium oxalate can be used to precipitate calcium to prepare calcium oxalate.

[0143] As another non-limiting example, the second fluid (e.g., a lithium-lean fluid) may contain carbon dioxide (CO2) and / or carbonic acid (H2CO3, e.g., by bubbling with CO2 gas), which can cause lithium to precipitate as lithium carbonate (Li2CO3). CO2 and / or H2CO3 may be present at any suitable concentration, such as at least 1 mmol, at least 3 mmol, at least 5 mmol, at least 10 mmol, at least 20 mmol, at least 30 mmol, etc. In some cases, Li2CO3 may precipitate at the outlet or outlet channel of the compartment.

[0144] In some respects, the apparatus described herein can be used to extract lithium from seawater, naturally occurring brine, or artificial brine from hydraulic fracturing, nuclear power plant wastewater, reverse osmosis, or other water treatment processes using localized freshwater or desalinated water as a recovery solution. In one embodiment, the apparatus can be co-located with a geothermal power plant that generates additional electricity. In another embodiment, the apparatus can be co-located with a blue energy plant at an estuary. In yet another embodiment, the apparatus can be used as a supplement to hydrometallurgical processes to extract lithium from acidic leachates from hard rock mining of spodumene or other lithium-bearing minerals, or from acidic leachates generated during Li-ion battery recovery. Other applications are also possible in other embodiments.

[0145] The following patent applications are incorporated herein by reference in their entirety: U.S. Patent Application Serial No. 63 / 440,889, filed January 24, 2023, entitled “Methods and Apparatuses for Galvanic Ion Extraction”; U.S. Patent Application Serial No. 63 / 444,484, filed February 9, 2023, entitled “Flow Field Configurations and Methods for Separation Process”; U.S. Patent Application Serial No. 63 / 513,519, filed July 13, 2023, entitled “Methods and Apparatuses for Electrochemical Ion Exchange”; and U.S. Patent Application Serial No. 63 / 513,519, filed July 13, 2023, entitled “Processes and Apparatuses for Enriching”. U.S. Patent Application Serial No. 63 / 513,532 entitled “Solutions [Methods and Apparatus for Enriching Solutions]”; and U.S. Patent Application Serial No. 63 / 513,538 entitled “Flow Systems and Methods for Membraneless Separation” filed on July 13, 2023.In addition, the following patent applications, each filed on the same date as this document, are incorporated herein by reference in their entirety: PCT patent application entitled "Methods and Apparatuses for Galvanic Ion Extraction"; PCT patent application entitled "Flow Field Configurations and Methods for Separation Processes"; PCT patent application entitled "Process and Apparatuses for Enriching Solutions"; PCT patent application entitled "Flow Systems and Methods for Membraneless Separation"; PCT patent application entitled "Electrode Composites for Electrochemical Ion Separation from Aqueous Solutions, and Methods Thereof"; and PCT patent application entitled "Apparatuses, Manufacturing, and Operation of Electrochemical Stacks for Metals Extraction, and Methods". The PCT patent application titled "[Apparatus, manufacture and operation of electrochemical stacks for metal extraction and methods thereof]".

[0146] The following examples are intended to illustrate certain embodiments of this disclosure, but do not represent the full scope of this disclosure.

[0147] Example 1

[0148] This example experiment demonstrates the use of lithium iron phosphate (LFP) as a Li-selective electrode material and woven activated carbon as a cation-selective element for Li extraction and release into solution. The LiFP electrode was fabricated by mixing LFP powder, conductive carbon powder, and polyvinylidene fluoride (PVDF) binder in an N-methyl-2-pyrrolidone solvent. After mixing, the resulting slurry was coated onto a carbon cloth substrate by dip coating or blade casting and then dried. To produce a Li-depleted electrode, the electrode was chemically oxidized at 50°C in a 0.1 M Na₂S₂O₈ solution for 1.5 hours, resulting in a Li-depleted electrode. 1-x The active material is composed of FePO4(FP) (where x>0). The activated carbon electrode is used as is or chemically modified via a sulfonation process.

[0149] Figure 4 illustrates a single cycle of Li extraction and release in a system containing a lithium-selective electrode and a magnesium-selective counter electrode. An aqueous solution of synthetic brine containing 2100 mg / L Li and 11750 mg / L Mg was flowed through a device containing two electrodes separated by a porous membrane. During the first half-cycle, a negative constant current was applied, simultaneously extracting Li into the working electrode and removing Mg from the counter electrode. This half-cycle is referred to as the “discharge” cycle. After the discharge cycle, the remaining brine was flushed from the cell, and the fluid was then switched to a solution containing 230 mg / L Li, 130 mg / L Mg, and 3900 mg / L K. During the next half-cycle, a positive constant current was applied, causing Li to be released from the working electrode and Mg to be extracted into the counter electrode (“charge”). The composition of the solution was measured using inductively coupled plasma mass spectrometry (ICP-MS).

[0150] Figure 4A The voltage of the electrochemical cell is shown during the charge and discharge half-cycle. Figure 4B The composition of the secondary solution, measured before and after the charging cycle, is shown.

[0151] Although several embodiments of this disclosure have been described and illustrated herein, those skilled in the art will readily conceive of a variety of other means and / or structures for performing the functions described herein and / or obtaining the results and / or one or more advantages described herein, and such variations and / or modifications are each considered to be within the scope of this disclosure. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications for which the teachings of this disclosure are intended. Those skilled in the art will recognize, or be able to determine, many equivalents of the specific embodiments of this disclosure described herein without the use of excessive conventional experimentation. Therefore, it should be understood that the foregoing embodiments are presented as examples only, and that this disclosure may be practiced in ways other than those specifically described and claimed within the scope of the appended claims and their equivalents. This disclosure relates to each individual feature, system, article of manufacture, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles of manufacture, materials, kits, and / or methods is included within the scope of this disclosure if such features, systems, articles of manufacture, materials, kits, and / or methods are not contradictory.

[0152] In the event of conflicting and / or inconsistent disclosures in this specification and in documents incorporated by reference, this specification shall prevail. If two or more documents incorporated by reference contain conflicting and / or inconsistent disclosures, the document with the later effective date shall prevail.

[0153] All definitions defined and used herein should be understood to take precedence over dictionary definitions, definitions cited in incorporated documents, and / or the general meaning of the defined terms.

[0154] As used herein in the specification and claims, the indefinite article “a / an” should be understood to mean “at least one / an” unless otherwise expressly stated.

[0155] As used herein in the specification and claims, the phrase “and / or” should be understood to mean “any one or both” of the elements so combined, that is, elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be interpreted in the same way, that is, “one or more” of the elements so combined. In addition to the elements specifically indicated by the “and / or” clause, other elements may optionally be present, whether related to or unrelated to those specifically indicated elements. Thus, as a non-limiting example, when used in conjunction with open-ended language such as “comprising,” a reference to “A and / or B” may in one embodiment refer only to A (optionally including elements other than B); in another embodiment it may refer only to B (optionally including elements other than A); in yet another embodiment it may refer to both A and B (optionally including other elements); and so on.

[0156] As used herein in the specification and 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” should be interpreted as inclusive, i.e., including a plurality of elements or at least one / a from a list of elements, including more than one / a from them, and optionally including additional items not listed. Only when explicitly contrary terms such as “only one / a from …” or “exact one / a from …” or when used in the claims, “consisting of …” will mean including a plurality of elements or exactly one / a from a list of elements. In general, as used herein, when the term “or” is preceded by an exclusive term such as “any one / a,” “one / a from …,” “only one / a from …,” or “exact one / a from …,” it should be interpreted only as indicating an exclusive alternative (i.e., “one / a or the other / a, but not both”).

[0157] As used herein in the specification and claims, the phrase "at least one" in relation to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list, but not necessarily including at least one of each element specifically listed in the list, and does not exclude any combination of elements in the list. This definition also allows for the optional presence of elements other than those specifically mentioned in the list of elements referred to by the phrase "at least one," whether related to or unrelated to those specifically mentioned elements. Therefore, 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") in one embodiment may refer to at least one, optionally including more than one, of A, without B (and optionally including elements other than B); in another embodiment, it may refer to at least one, optionally including more than one, of B, without A (and optionally including elements other than A); in yet another embodiment, it may refer to at least one, optionally including more than one, of A, and at least one, optionally including more than one, of B (and optionally including other elements); and so on.

[0158] When the word “about” is used in relation to numbers in this document, it should be understood that another embodiment of this disclosure includes numbers that are not modified by the presence of the word “about”.

[0159] It should also be understood that, unless expressly stated to the contrary, in any method claimed herein that includes more than one step or action, the order of the steps or actions of the method is not necessarily limited to the order in which the steps or actions of the method are listed.

[0160] In the claims and in the foregoing description, all conjunctions such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “constituting,” etc., shall be understood as open-ended, that is, meaning including but not limited to. As described in Section 2111.03 of the United States Patent Office Manual of Patent Examining Procedures, only the conjunctions “constituting of” and “substantially consisting of” shall be closed or semi-closed conjunctions, respectively.

Claims

1. An apparatus for electrochemical extraction of lithium, the apparatus comprising: A compartment, wherein the compartment houses a lithium-selective electrode and a multivalent cation-selective electrode; An electrical pathway connecting the lithium-selective electrode and the multivalent cation-selective electrode; Lithium-rich fluid source; Lithium-poor fluid source; as well as A flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-poor fluid source into the compartment.

2. The apparatus of claim 1, wherein, The multivalent cation selective electrode is a divalent cation selective electrode.

3. The apparatus as described in any one of claims 1 or 2, wherein, The multivalent cation selective electrode includes a Mg selective electrode.

4. The apparatus according to any one of claims 1-3, wherein, The multivalent cation-selective electrode includes a Mn-selective electrode.

5. The apparatus according to any one of claims 1-4, wherein, The multivalent cation-selective electrode includes a Ni-selective electrode.

6. The apparatus according to any one of claims 1-5, wherein, The multivalent cation-selective electrode includes a Ca-selective electrode.

7. The apparatus according to any one of claims 1-6, wherein, The multivalent cation selective electrode includes a Cu selective electrode.

8. The apparatus according to any one of claims 1-7, wherein, The multivalent cation-selective electrode includes a Zn-selective electrode.

9. The apparatus according to any one of claims 1-8, wherein, The multivalent cation-selective electrode includes a Co-selective electrode.

10. The apparatus according to any one of claims 1-9, wherein, The multivalent cation selective electrode includes a lanthanide element selective electrode.

11. The apparatus according to any one of claims 1-10, wherein, The multivalent cation selective electrode includes an actinide element selective electrode.

12. The apparatus according to any one of claims 1-11, wherein, The multivalent cation selective electrode is functionalized with carboxylic acid.

13. The apparatus according to any one of claims 1-12, wherein, The multivalent cation selective electrode is functionalized with sulfonic acid.

14. The apparatus according to any one of claims 1-13, wherein, The multivalent cation selective electrode is phosphoric acid functionalized.

15. The apparatus according to any one of claims 1-14, wherein, The multivalent cation selective electrode is porous.

16. The apparatus of claim 15, wherein, The multivalent cation selective electrode has a porosity of at least 20%.

17. The apparatus of any one of claims 15 or 16, wherein, The multivalent cation selective electrode has a porosity of at least 25%.

18. The apparatus according to any one of claims 15-17, wherein, The multivalent cation selective electrode has a porosity of at least 30%.

19. The apparatus according to any one of claims 15-18, wherein, The multivalent cation selective electrode has a porosity between 20% and 80%.

20. The apparatus according to any one of claims 15-19, wherein, The multivalent cation selective electrode has a porosity between 25% and 70%.

21. The apparatus according to any one of claims 1-20, wherein, The multivalent cation selective electrode comprises particles.

22. The apparatus according to any one of claims 1-21, wherein, The multivalent cation selective electrode comprises fibers.

23. The apparatus according to any one of claims 1-22, wherein, The multivalent cation selective electrode comprises woven fibers.

24. The apparatus according to any one of claims 1-23, wherein, The multivalent cation selective electrode comprises nonwoven fibers.

25. The apparatus according to any one of claims 1-24, wherein, The multivalent cation selective electrode contains carbon.

26. The apparatus according to any one of claims 1-25, wherein, The multivalent cation selective electrode contains activated carbon.

27. The apparatus according to any one of claims 1-26, wherein, The multivalent cation-selective electrode comprises carbon nanotubes.

28. The apparatus according to any one of claims 1-27, wherein, The multivalent cation selective electrode contains graphene.

29. The apparatus according to any one of claims 1-28, wherein, The multivalent cation-selective electrode comprises carbon aerogel.

30. The apparatus according to any one of claims 1-29, wherein, The multivalent cation selective electrode includes a first portion and a second portion, wherein the first portion is functionalized and the second portion is not functionalized.

31. The apparatus of claim 30, wherein, The first portion of the multivalent cation selective electrode is in physical contact with the second portion.

32. The apparatus of claim 30, wherein, The first portion of the multivalent cation selective electrode is separate from the second portion.

33. The apparatus according to any one of claims 1-32, wherein, The multivalent cation selective electrode is a flow-through electrode.

34. The apparatus according to any one of claims 1-33, wherein, The multivalent cation selective electrode includes a current collector.

35. The apparatus of claim 34, wherein, The current collector includes graphite.

36. The apparatus as claimed in any one of claims 34 or 35, wherein, The current collector includes titanium.

37. The apparatus according to any one of claims 34-36, wherein, The current collector comprises aluminum.

38. The apparatus according to any one of claims 34-37, wherein, The current collector includes a metal mesh.

39. The apparatus according to any one of claims 33-38, wherein, The current collector comprises a porous conductive material.

40. The apparatus according to any one of claims 1-39, wherein, The multivalent cation selective electrode contains an intercalating agent.

41. The apparatus according to any one of claims 1-40, wherein, The compartment did not contain a membrane.

42. The apparatus according to any one of claims 1-41, wherein, The lithium-selective electrode and the multivalent cation-selective electrode are substantially parallel to each other within the compartment.

43. The apparatus according to any one of claims 1-42, wherein, The lithium-selective electrode and the multivalent cation-selective electrode are substantially perpendicular to each other within the compartment.

44. The apparatus according to any one of claims 1-43, wherein, The lithium selective electrode contains an active material.

45. The apparatus of claim 44, wherein, The active material includes solid metals.

46. ​​The apparatus of claim 45, wherein, The solid metal includes lithium metal.

47. The apparatus according to any one of claims 44-46, wherein, The active material includes a lithium-ion intercalating material.

48. The apparatus of claim 47, wherein, The lithium-ion intercalation material includes LiMePO4, wherein Me includes one or more transition metals.

49. The apparatus of any one of claims 47 or 48, wherein, The lithium-ion intercalation material includes LiMeO2, wherein Me includes one or more transition metals.

50. The apparatus of claim 49, wherein, The lithium-ion intercalation material includes lithium iron phosphate (LFP).

51. The apparatus as claimed in any one of claims 47 or 50, wherein, The lithium-ion intercalation material includes lithium titanium phosphate (LTP).

52. The apparatus according to any one of claims 47-51, wherein, The lithium-ion intercalation material includes lithium manganese oxide (LMO).

53. The apparatus according to any one of claims 47-52, wherein, The lithium-ion intercalation material includes lithium titanium oxide (LTO).

54. The apparatus according to any one of claims 47-53, wherein, The lithium-ion intercalation material includes nickel manganese cobalt oxide (NMC).

55. The apparatus according to any one of claims 47-54, wherein, The lithium-ion intercalation material includes nickel cobalt aluminum oxide (NCA).

56. The apparatus according to any one of claims 47-55, wherein, The lithium-ion intercalation material includes lithium cobalt oxide (LCO).

57. The apparatus according to any one of claims 47-56, wherein, The lithium-ion intercalating material contains manganese.

58. The apparatus according to any one of claims 47-57, wherein, The lithium-ion intercalating material contains nickel.

59. The apparatus according to any one of claims 1-58, wherein, The lithium selective electrode further includes a coating.

60. The apparatus of claim 59, wherein, The coating surrounds at least a portion of the active material.

61. The apparatus of any one of claims 59 or 60, wherein, The coating contains the active material.

62. The apparatus according to any one of claims 59-61, wherein, The coating contains a lithium-selective material.

63. The apparatus of claim 62, wherein, The lithium-selective material includes lithium titanium oxide.

64. The apparatus as claimed in any one of claims 62 or 63, wherein, The lithium-selective material includes polydopamine carbon.

65. The apparatus according to any one of claims 62-64, wherein, The lithium-selective material includes carbon nanotubes.

66. The apparatus according to any one of claims 1-65, wherein, The lithium selective electrode comprises ceramic.

67. The apparatus of claim 66, wherein, The ceramic includes alumina.

68. The apparatus of any one of claims 66 or 67, wherein, The ceramic includes titanium dioxide.

69. The apparatus according to any one of claims 66-68, wherein, The ceramic includes zirconium oxide.

70. The apparatus according to any one of claims 66-69, wherein, The ceramic includes phosphate glass.

71. The apparatus according to any one of claims 1-70, wherein, The lithium selective electrode contains conductive additives.

72. The apparatus of claim 71, wherein, The additives include carbon.

73. The apparatus as claimed in any one of claims 71 or 72, wherein, The additives include graphite carbon.

74. The apparatus according to any one of claims 71-73, wherein, The additives include carbon black.

75. The apparatus according to any one of claims 71-74, wherein, The additives include graphene oxide.

76. The apparatus according to any one of claims 1-75, wherein, The lithium selective electrode contains a binder.

77. The apparatus of claim 76, wherein, The adhesive comprises polyvinylidene fluoride (PVDF).

78. The apparatus as claimed in any one of claims 76 or 77, wherein, The adhesive includes polypyrrole (PPy).

79. The apparatus according to any one of claims 76-78, wherein, The adhesive comprises polyethylene oxide (PEO).

80. The apparatus according to any one of claims 1-79, wherein, The lithium selective electrode is porous.

81. The apparatus of claim 80, wherein, The lithium selective electrode has a porosity of at least 25%.

82. The apparatus as claimed in any one of claims 80 or 81, wherein, The lithium selective electrode has a porosity of at least 30%.

83. The apparatus according to any one of claims 80-82, wherein, The lithium selective electrode has a porosity between 25% and 70%.

84. The apparatus according to any one of claims 80-83, wherein, The porous electrode is formed using a pore-forming agent.

85. The apparatus according to any one of claims 1-84, wherein, The lithium selective electrode contains particles.

86. The apparatus of claim 85, wherein, The particles form a packed bed within the lithium selective electrode.

87. The apparatus as claimed in any one of claims 85 or 86, wherein, The particles include carbon particles.

88. The apparatus as claimed in any one of claims 85-87, wherein, The particles include Vulcan carbon.

89. The apparatus of claim 88, wherein, The particles include petroleum coke.

90. The apparatus according to any one of claims 1-89, wherein, The lithium selective electrode comprises fibers.

91. The apparatus according to any one of claims 1-90, wherein, The lithium selective electrode comprises woven fibers.

92. The apparatus according to any one of claims 1-91, wherein, The lithium selective electrode comprises nonwoven fibers.

93. The apparatus according to any one of claims 1-92, wherein, The lithium selective electrode is a flow-through electrode.

94. The apparatus according to any one of claims 1-93, wherein, The lithium selective electrode includes a current collector.

95. The apparatus of claim 94, wherein, The current collector includes graphite.

96. The apparatus as claimed in any one of claims 94 or 95, wherein, The current collector includes titanium.

97. The apparatus as claimed in any one of claims 94-96, wherein, The current collector comprises aluminum.

98. The apparatus as claimed in any one of claims 94-97, wherein, The current collector includes a metal mesh.

99. The apparatus as claimed in any one of claims 94-98, wherein, The current collector comprises a porous conductive material.

100. The apparatus according to any one of claims 94-99, wherein, The porous conductive material has a porosity of less than 75%.

101. The apparatus according to any one of claims 1-100, wherein, The lithium-rich fluid includes salt lake brine.

102. The apparatus according to any one of claims 1-101, wherein, The lithium-rich fluid includes geothermal brine.

103. The apparatus according to any one of claims 1-102, wherein, The lithium-rich fluid includes artificially desalinated brine.

104. The apparatus according to any one of claims 1-103, wherein, The lithium-rich fluid includes hard rock leachate.

105. The apparatus according to any one of claims 1-104, wherein, The lithium-rich fluid includes battery leaching solution.

106. The apparatus according to any one of claims 1-105, wherein, The lithium-rich fluid includes seawater.

107. The apparatus according to any one of claims 1-106, wherein, The lithium-rich fluid contains at least 0.2 mol% lithium ion concentration.

108. The apparatus according to any one of claims 1-107, wherein, The lithium-rich fluid contains at least 0.5 mol% lithium ion concentration.

109. The apparatus according to any one of claims 1-108, wherein, The lithium-rich fluid contains at least 1 mol% lithium ion concentration.

110. The apparatus according to any one of claims 1-109, wherein, The lithium-rich fluid contains at least 3 mol% lithium ion concentration.

111. The apparatus according to any one of claims 1-110, wherein, The lithium-poor fluid contains a lithium ion concentration of no more than 0.01 mol%.

112. The apparatus according to any one of claims 1-111, wherein, The lithium-poor fluid includes fresh water.

113. The apparatus according to any one of claims 1-112, wherein, The lithium-poor fluid includes purified water.

114. The apparatus according to any one of claims 1-113, wherein, The lithium-poor fluid includes demineralized water.

115. The apparatus according to any one of claims 1-114, wherein, The lithium-poor fluid has a pH of at least 5.

116. The apparatus according to any one of claims 1-115, wherein, The lithium-poor fluid has a pH of at least 6.

117. The apparatus according to any one of claims 1-116, wherein, The lithium-poor fluid contains a CO2 concentration of at least 1 mmol.

118. The apparatus according to any one of claims 1-117, wherein, The lithium-poor fluid contains a CO2 concentration of at least 5 mmol.

119. The apparatus according to any one of claims 1-118, wherein, The lithium-poor fluid contains a CO2 concentration of at least 10 mmol.

120. The apparatus according to any one of claims 1-119, wherein, The lithium-poor fluid contains a CO2 concentration of at least 30 mmol.

121. An apparatus for electrochemical extraction of lithium, the apparatus comprising: A stack comprising a plurality of repeating units, each repeating unit comprising a compartment and an electrical pathway, the compartment accommodating a lithium-selective electrode and a multivalent cation-selective electrode, the electrical pathway connecting the lithium-selective electrode and the multivalent cation-selective electrode; Lithium-rich fluid source; Lithium-poor fluid source; as well as A flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-poor fluid source into the compartment within the stack.

122. The apparatus of claim 121, wherein, Fluid flows in parallel within adjacent compartments of the stack.

123. The apparatus as claimed in any one of claims 121 or 122, wherein, Fluid flow is antiparallel in adjacent compartments within the stack.

124. The apparatus according to any one of claims 121-123, wherein, Fluids in adjacent compartments within the stack flow orthogonally.

125. The apparatus according to any one of claims 121-124, wherein, The stack has a rectangular compartment configuration.

126. The apparatus according to any one of claims 121-125, wherein, The stack has a cylindrical compartmentalized configuration.

127. A method for electrochemical extraction of lithium, the method comprising: An electrochemical battery cell is provided, the electrochemical battery cell including a compartment that houses a lithium-selective electrode and a multivalent cation-selective electrode; At the first moment, while the lithium-rich fluid flows through the compartment, current is caused to flow from the lithium-selective electrode to the multivalent cation-selective electrode; as well as At the second time, while the lithium-poor fluid flows through the compartment, current is caused to flow from the multivalent cation-selective electrode to the lithium-selective electrode.

128. The method of claim 127, wherein, At the first time, lithium from the lithium-rich fluid is transferred to the lithium-selective electrode, and at the second time, lithium is removed from the lithium-selective electrode and transferred to the lithium-poor fluid.

129. The method of any one of claims 127 or 128, the method further comprising flowing the lithium-rich fluid through the multivalent cation-selective electrode.

130. The method of any one of claims 127-129, the method further comprising flowing the lithium-depleted fluid through the multivalent cation-selective electrode.

131. The method of any one of claims 127-130, the method further comprising flowing the lithium-rich fluid through the lithium-selective electrode.

132. The method of any one of claims 127-131, the method further comprising flowing the lithium-depleted fluid through the lithium-selective electrode.

133. The method according to any one of claims 127-132, wherein, The compartment further includes an anode.

134. The method of claim 133, further comprising, at a first time, binding anions from the lithium-rich fluid to the anode.

135. The method of any one of claims 133 or 134, the method further comprising, at a second time, removing anions from the anode into the lithium-depleted fluid.

136. The method according to any one of claims 133-135, wherein, The anode is in physical contact with the multivalent cation selective electrode.

137. The method according to any one of claims 133-136, wherein, The anode is separate from the multivalent cation selective electrode.

138. A method for electrochemical extraction of lithium, the method comprising: An electrochemical battery cell is provided, the electrochemical battery cell including a compartment that houses a lithium-selective electrode and a multivalent cation-selective electrode; In the first instant, lithium-rich fluid is allowed to flow through the compartment, lithium ions from the lithium-rich fluid are bound to the lithium selective electrode, and multivalent cations are removed from the multivalent cation selective electrode into the lithium-rich fluid; as well as At a second time, a lithium-deficient fluid is allowed to flow through the compartment, removing lithium ions from the lithium-selective electrode into the lithium-deficient fluid, and binding multivalent cations from the lithium-deficient fluid into the multivalent cation-selective electrode.

139. The method of claim 138, further comprising, at a first time, causing current to flow from the lithium-selective electrode to the multivalent cation-selective electrode, and at a second time, causing current to flow from the multivalent cation-selective electrode to the lithium-selective electrode.

140. The method of any one of claims 138 or 139, the method further comprising flowing the lithium-rich fluid through the multivalent cation selective electrode.

141. The method of any one of claims 138-140, the method further comprising flowing the lithium-depleted fluid through the multivalent cation-selective electrode.

142. The method of any one of claims 138-141, the method further comprising flowing the lithium-rich fluid through the lithium-selective electrode.

143. The method of any one of claims 138-142, the method further comprising flowing the lithium-depleted fluid through the lithium-selective electrode.

144. The method according to any one of claims 138-143, wherein, The compartment further includes an anode.

145. The method of claim 144, further comprising, at a first time, binding anions from the lithium-rich fluid to the anode.

146. The method of any one of claims 144 or 145, the method further comprising, at a second time, removing anions from the anode into the lithium-depleted fluid.

147. The method according to any one of claims 144-146, wherein, The anode is in physical contact with the multivalent cation selective electrode.

148. The method according to any one of claims 144-147, wherein, The anode is separate from the multivalent cation selective electrode.

149. An apparatus for electrochemical extraction of target monovalent ions, the apparatus comprising: A compartment, wherein the compartment contains a target monovalent ion selective electrode and a multivalent cation selective electrode; An electrical pathway, wherein the electrical pathway connects the target monovalent ion selective electrode and the multivalent cation selective electrode; Rich target monovalent ion fluid source; Depleted target unit valence ion fluid source; as well as A flow switching element capable of directing fluid from either the target-rich monovalent ion fluid source or the target-poor monovalent ion fluid source into the compartment.

150. The apparatus of claim 149, wherein, The target monovalent ion is positively charged.

151. The apparatus as claimed in any one of claims 149 or 150, wherein, The target monovalent ion is Li. + .

152. The apparatus as claimed in any one of claims 149 or 150, wherein, The target monovalent ion is Na. + .

153. The apparatus as described in any one of claims 149 or 150, wherein, The target monovalent ion is K. + .

154. The apparatus as claimed in any one of claims 149 or 150, wherein, The target monovalent ion is H. + .

155. The apparatus of claim 149, wherein, The target monovalent ion is negatively charged.

156. The apparatus as claimed in any one of claims 149 or 155, wherein, The target monovalent ion is Cl. - .

157. The apparatus according to any one of claims 149-156, wherein, The multivalent cation selective electrode is a multivalent cation selective electrode.

158. The apparatus according to any one of claims 149-157, wherein, The multivalent cation selective electrode is a Mg selective electrode.

159. The apparatus according to any one of claims 149-158, wherein, The multivalent cation-selective electrode is a Mn-selective electrode.

160. The apparatus according to any one of claims 149-159, wherein, The multivalent cation-selective electrode is a Ni-selective electrode.

161. An apparatus for electrochemical extraction of target monovalent ions, the apparatus comprising: A stack comprising multiple repeating units, each repeating unit comprising a compartment and an electrical pathway, the compartment accommodating a target monovalent ion selective electrode and a multivalent cation selective electrode, the electrical pathway connecting the target monovalent ion selective electrode and the multivalent cation selective electrode; Rich target monovalent ion fluid source; Depleted target unit valence ion fluid source; as well as A flow switching element capable of directing fluid from the target-rich monovalent ion fluid source or the target-poor monovalent ion fluid source into the compartment within the stack.

162. The apparatus of claim 161, wherein, The target monovalent ion is Li. + .

163. The apparatus of claim 161, wherein, The target monovalent ion is Na. + .

164. The apparatus of claim 161, wherein, The target monovalent ion is K. + .

165. A method for electrochemical extraction of target monovalent ions, the method comprising: An electrochemical cell unit is provided, the electrochemical cell unit including a compartment that houses a target monovalent ion selective electrode and a multivalent cation selective electrode; At the first moment, while the target monovalent ion-rich fluid flows through the compartment, current is caused to flow from the target monovalent ion selective electrode to the multivalent cation selective electrode; as well as At the second time, while the depleted target monovalent ion fluid flows through the compartment, current is caused to flow from the multivalent cation selective electrode to the target monovalent ion selective electrode.

166. The apparatus of claim 165, wherein, The target monovalent ion is Li. + .

167. The apparatus of claim 165, wherein, The target monovalent ion is Na. + .

168. The apparatus of claim 165, wherein, The target monovalent ion is K. + .

169. A method for electrochemical extraction of target monovalent ions, the method comprising: An electrochemical cell unit is provided, the electrochemical cell unit including a compartment that houses a target monovalent ion selective electrode and a multivalent cation selective electrode; In the first instant, the target monovalent ion-rich fluid is allowed to flow through the compartment, the target monovalent ions from the target monovalent ion-rich fluid are bound to the target monovalent ion selective electrode, and the multivalent cations are removed from the multivalent cation selective electrode to the target monovalent ion-rich fluid; as well as At a second time, the depleted target monovalent ion fluid is allowed to flow through the compartment, removing the target monovalent ions from the target monovalent ion selective electrode into the depleted target monovalent ion fluid, and binding the multivalent cations from the depleted target monovalent ion fluid to the multivalent cation selective electrode.

170. The apparatus of claim 169, wherein, The target monovalent ion is Li. + .

171. The apparatus of claim 169, wherein, The target monovalent ion is Na. + .

172. The apparatus of claim 169, wherein, The target monovalent ion is K. + .

173. An apparatus for electrochemical extraction of lithium, the apparatus comprising: A compartment that houses a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; An electrical pathway connecting the lithium-selective electrode and the monovalent cation-selective electrode; Lithium-rich fluid source; Lithium-poor fluid source; as well as A flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-poor fluid source into the compartment.

174. The apparatus of claim 173, wherein, The monovalent cation-selective electrode is a sodium-selective cathode.

175. The apparatus of claim 173, wherein, The monovalent cation-selective electrode is a potassium-selective cathode.

176. A method for electrochemical extraction of target monovalent ions, the method comprising: An electrochemical cell unit is provided, the electrochemical cell unit including a compartment that houses a target monovalent ion selective electrode and a non-target monovalent cation selective electrode; In the first instant, the target monovalent ion-rich fluid is allowed to flow through the compartment, the target monovalent ions from the target monovalent ion-rich fluid are bound to the target monovalent ion selective electrode, and the non-target monovalent cations are removed from the non-target monovalent cation selective electrode to the target monovalent ion-rich fluid. as well as At the second time, the depleted target monovalent ion fluid is allowed to flow through the compartment, removing target monovalent ions from the target monovalent ion selective electrode into the depleted target monovalent ion fluid, and binding non-target monovalent cations from the depleted target monovalent ion fluid to the non-target monovalent cation selective electrode.

177. A method for electrochemical extraction of lithium, the method comprising: An electrochemical battery cell is provided, the electrochemical battery cell including a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; At the first moment, while the lithium-rich fluid flows through the compartment, current is caused to flow from the lithium-selective electrode to the monovalent cation-selective electrode; as well as At the second time, while the lithium-poor fluid flows through the compartment, current is caused to flow from the monovalent cation-selective electrode to the lithium-selective electrode.

178. A method for electrochemical extraction of lithium, the method comprising: An electrochemical battery cell is provided, the electrochemical battery cell including a compartment housing a lithium-selective electrode and a monovalent cation-selective electrode, wherein the monovalent cation is not lithium; In the first instant, lithium-rich fluid is allowed to flow through the compartment, lithium ions from the lithium-rich fluid are bound to the lithium selective electrode, and monovalent cations are removed from the monovalent cation selective electrode into the lithium-rich fluid; as well as At a second time, a lithium-deficient fluid is allowed to flow through the compartment, removing lithium ions from the lithium-selective electrode into the lithium-deficient fluid, and binding monovalent cations from the lithium-deficient fluid into the monovalent cation-selective electrode.

179. An apparatus for electrochemical extraction of target monovalent ions, the apparatus comprising: A compartment, wherein the compartment contains a target monovalent ion selective electrode and a non-target monovalent cation selective electrode; An electrical pathway, wherein the electrical pathway connects the target monovalent ion selective electrode and the multivalent cation selective electrode; Rich target monovalent ion fluid source; Depleted target unit valence ion fluid source; as well as A flow switching element capable of directing fluid from either the target-rich monovalent ion fluid source or the target-poor monovalent ion fluid source into the compartment.

180. An apparatus for electrochemical extraction of target monovalent ions, the apparatus comprising: A stack comprising multiple repeating units, each repeating unit comprising a compartment and an electrical pathway, the compartment accommodating a target monovalent ion selective electrode and a non-target monovalent cation selective electrode, the electrical pathway connecting the target monovalent ion selective electrode and the non-target monovalent cation selective electrode; Rich target monovalent ion fluid source; Depleted target unit valence ion fluid source; as well as A flow switching element capable of directing fluid from the target-rich monovalent ion fluid source or the target-poor monovalent ion fluid source into the compartment within the stack.

181. A method for electrochemical extraction of target monovalent ions, the method comprising: An electrochemical cell unit is provided, the electrochemical cell unit including a compartment that houses a target monovalent ion selective electrode and a non-target monovalent cation selective electrode; At the first moment, while the target monovalent ion-rich fluid flows through the compartment, current is caused to flow from the target monovalent ion selective electrode to the non-target monovalent cation selective electrode; as well as At the second time, while the target monovalent ion fluid is flowing through the compartment, current is caused to flow from the non-target monovalent cation selective electrode to the target monovalent ion selective electrode.

182. An apparatus for electrochemical extraction of lithium, the apparatus comprising: A stack comprising a plurality of repeating units, each repeating unit comprising a compartment and an electrical pathway, the compartment accommodating a lithium-selective electrode and a monovalent cation-selective electrode, the electrical pathway connecting the lithium-selective electrode and the monovalent cation-selective electrode, wherein the monovalent cation is not lithium; Lithium-rich fluid source; Lithium-poor fluid source; as well as A flow switching element capable of directing fluid from the lithium-rich fluid source or the lithium-poor fluid source into the compartment within the stack.

183. The apparatus of claim 182, wherein, The monovalent cation-selective electrode includes a sodium-selective electrode.

184. The apparatus as claimed in any one of claims 182 or 183, wherein, The monovalent cation-selective electrode includes a potassium-selective electrode.

185. The apparatus according to any one of claims 182-184, wherein, The monovalent cation-selective electrode includes a rubidium-selective electrode.

186. The apparatus according to any one of claims 182-185, wherein, The monovalent cation-selective electrode includes a cesium-selective electrode.

187. The apparatus according to any one of claims 182-186, wherein, The monovalent cation-selective electrode includes a francium-selective electrode.

188. The apparatus according to any one of claims 182-187, wherein, The lithium selectivity of the monovalent cation selective electrode is less than that of the lithium selective electrode.

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