Redox membranes for lithium extraction.

Abstract

Apparatus, systems and redox membranes are provided for efficient lithium ion extraction from natural saltwater or artificial sources such as geothermal brines or lithium battery recycling. The redox membrane is selective for lithium ions over other bystander ions, allowing the system to selectively extract lithium ions from a multi-ion source solution. The system uses the redox membrane as an electrochemically active material that acts as a Li-selective membrane for direct lithium extraction from the lithium ion source. The redox membrane is also non-porous to solvents and stable in caustic and high temperature environments. The features of the redox membrane and system allow for the recovery of lithium from low purity sources and the production of a higher purity product at lower costs and process steps than conventional processes.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 325,830, filed March 31, 2022, which is incorporated by reference in its entirety.

[0002] Federally funded research institution statement N / A Notice of copyrighted material

[0003] Portions of the material in this patent document are subject to copyright protection under the copyright laws of the United States and other countries. The copyright owner has no objection to the facsimile reproduction of either the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office publicly available files or records, but otherwise reserves all copyright rights. The copyright owner has not waived any of its rights to maintain this patent document in confidence, including, but not limited to, the right pursuant to 37 C.FR § 1.14. background

[0004] 1.Technical Field

[0005] The present technology relates generally to ion extraction systems and methods, and more particularly to electrochemically active redox membranes and systems capable of directly extracting lithium ions from an ion extraction source and producing a high purity Li-rich product. [Background technology]

[0006] 2.Background

[0007] Lithium is an essential element in the manufacture of lithium-ion batteries, which have long cycle life and offer superior energy density and high operating voltages over other types of batteries. Highly refined lithium compounds are also utilized in the manufacture of strong, light-weight metal alloys, as well as in pharmaceuticals, biomedical applications, the synthesis of organic compounds, and other industrial processes and products such as ceramics, specialty glass, synthetic rubber, dyes, and lubricating greases. These processes use various forms of lithium in addition to lithium metal, including lithium carbonate, lithium hydroxide, lithium chloride, and butyllithium.

[0008] The huge increase in the demand for lithium worldwide has prompted the need for improved recovery processes from geological and recycled sources. These sources are generally found in either liquid or solid sources. Solid sources are mined ores such as pegmatite, spodumene, lepidolite and petalite. Recycled batteries and electronic waste can also be solid sources of lithium.

[0009] Common liquid sources of lithium are typically salt lake brines, seawater, geothermal brines, desalination plants, and oil field brines. Lithium ion concentrations from these liquid sources can vary widely, from about (0.17 mg / L) in seawater to about 100-1000 mg / L in salt brines. These liquid sources also contain sodium (Na+), magnesium (Mg+), and other metals that can complicate the extraction of Li from the brines. 2+ ) and calcium (Ca 2+ ), as well as chloride (Cl - ), Carbonic acid (CO3 2- ) and sulfuric acid (SO4 2- ).

[0010] Ion-rich solutions such as salt water or geothermal brines contain a mixture of cations and anions with concentrations varying by orders of magnitude. Currently, extraction of individual cationic species into purified products is a time-consuming, multi-step process. In the case of solar brines, solar evaporation is used to reduce the water content of the ionic medium which increases the concentration of the solutes. A series of separation techniques such as solvent extraction, ion precipitation, flotation and filtration are used to sequentially separate value-added products from the ionic medium.

[0011] Ion absorbing media, such as layered double hydroxides or electrochemically active materials, that can selectively extract lithium ions from multi-ionic component aqueous solutions have also been developed. These separation techniques utilize a three-stage operation to achieve ion separation. In the first step, the absorbing media is exposed to a lithium ion-containing brine solution. By chemical or electrochemical means, lithium ions are selectively absorbed into the media until saturation occurs. The second step removes the lithium ion saturated media from the brine solution and uses a rinse solution to remove residual brine. In the final step, the lithium ion saturated media is exposed to a pure aqueous solution where the lithium ions are released (chemically or electrochemically) into the pure aqueous solution to obtain a purified lithium product. This process is repeated indefinitely to continuously produce a purified lithium product. Although essentially a batch process, columns containing multiple absorbing media can be utilized so that regeneration and absorption of lithium can occur simultaneously, resulting in a continuous process.

[0012] Other extraction methods utilize ion-selective membranes to produce high purity products. For direct lithium ion extraction, membrane technologies such as supported liquid membranes, nanofiltration membranes, and selective electrodialysis (utilizing ion exchange membranes) have been investigated in academic and pilot-scale settings. These ion extraction membranes typically exhibit high selectivity for lithium ions and can achieve recoveries of over 80%. The transport of ions through the membrane is typically driven by a concentration gradient or pressure gradient. This separation technique works on lithium transport through the membrane layer rather than lithium ion adsorption, which requires a regeneration stream during operation, and therefore can avoid excessive waste streams in some scenarios.

[0013] Thus, there is a need for new systems, apparatus and schemes to enable reliable extraction of lithium from liquid or solid sources that are efficient, scalable, have low energy requirements, and have reduced capital and operating costs. Summary of the Invention [Means for solving the problem]

[0014] A system and method for lithium ion extraction using novel electrochemically active redox membranes that allows for the production of high lithium purity products and fluids with high ion concentrations as feedstocks for a variety of applications. The redox membranes can be adapted to extract Li-ions from a variety of liquid ion extraction sources, which may be natural or man-made.

[0015] The present invention combines the functions of an ion-absorbing medium and a membrane to form an electrochemically active redox membrane. Like conventional membranes, redox membranes are solvent-blocking but allow the passage of certain ions. The ion permeability and selectivity can be controlled by the redox couple in the membrane.

[0016] For example, in the case of lithium cobalt oxide (LiCoO2) redox film, Co 3 / 4+The pair can reversibly drive lithium ions into the redox film from one interface and release lithium ions at the opposite interface. However, because the redox film cannot simultaneously absorb and release ions, the redox film also functions as an ion-absorbing material with successive lithium uptake and release steps. The advantage of combining the membrane function with the absorption medium function is that high-purity lithium products can be produced directly from low-purity lithium sources. In one embodiment, lithium extracted using the LCO redox film is converted to Li-containing products such as inorganic and organic lithium salts, prelithiated or lithium-containing battery materials, and lithium metal.

[0017] LiCoO2 (LCO) is in the space group R

number

[0018] In another embodiment, the redox film is made by growing the redox film on a substrate via vapor deposition or in a molten salt electroplating bath, then removing the substrate and annealing the film to close the pores and obtain a solvent-blocking material. In another embodiment, the LCO powder is packed into pellets and sintered to produce the solvent-blocking redox film.

[0019] The ion extraction source can contain ions ranging from low to high concentrations (ppm levels up to saturated solutions). The ion extraction source may also contain some additional dissolved solids such as potassium, calcium and magnesium bicarbonates, chlorides and nitrates, silica, etc. The ion extraction source may also be an aqueous, organic, or molten salt solution. In one embodiment, a redox membrane is used for the selective extraction of lithium from a battery that may or may not have been previously used.

[0020] In one embodiment, the LCO material is used as a redox membrane to extract lithium from a lithium-containing aqueous solution. The aqueous solution is an electrolyte with dissolved LiCl, LiOH, Li2CO3, Li2SO4, or LiNO3, LiBr, LiF, or LiI, and combinations thereof. The aqueous solution can also contain other cationic and anionic species against which the redox membrane acts selectively.

[0021] In one embodiment, an LCO redox membrane is used to extract lithium from a lithium-containing solution, which is then transferred to pure water.

[0022] In another embodiment, the LCO redox membrane extracts lithium ions from an aqueous solution and transfers them to an organic lithium-containing solution. Lithium metal is simultaneously plated onto a metal substrate in an organic medium. Alternatively, lithium extracted from an aqueous solution can be plated onto a metal substrate through a solid electrolyte.

[0023] In one embodiment, an LCO redox membrane for lithium metal plating can be designed in a continuous R2R process, where a metal substrate is transferred into an organolithium-containing electrolyte, plated with lithium metal, and then transferred out of the electrolyte.

[0024] In another embodiment, the LCO is used as a redox membrane to extract lithium from a lithium-containing aqueous solution. In another embodiment, the LCO redox membrane extracts lithium ions from an aqueous solution and releases them into an organic lithium-containing solution. Lithium can be simultaneously deposited on a lithium-ion battery anode material and transferred into or out of the organic solution in either a batch process or a R2R process. In this way, the lithium-ion battery anode is prelithiated with lithium, improving the performance of the lithium-ion battery.

[0025] In another embodiment, a metal substrate is laminated to the solid electrolyte. Lithium is plated between the metal substrate (or current collector) and the solid electrolyte. A lithium anode / solid electrolyte composite is then formed in a single deposition process.

[0026] In another embodiment, the solid electrolyte is coated on the redox film. The metal substrate is moved to contact the redox film / solid electrolyte assembly. The redox film / solid electrolyte assembly can be shaped in various geometric formats to facilitate intimate contact between the redox film and the solid electrolyte to provide uniform current distribution during electroplating.

[0027] The process of extracting lithium from saline groundwater is time consuming, requires multiple processing steps, and generates excessive waste streams. Using redox membranes, direct lithium extraction can be utilized to avoid most of the traditional processing steps required to obtain pure lithium products from lithium extraction sources, thereby avoiding the cost and energy required in these systems. Brief description of some figures of the drawing

[0028] Further aspects of the technology described herein will be set forth in the remainder of the specification, the detailed description being intended to fully disclose preferred embodiments of the technology without imposing limitations.

[0029] The techniques described herein may be more fully understood by reference to the following drawings, which are for illustrative purposes only. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic conceptual diagram of a redox membrane-based system that enables the extraction of lithium ions from a lithium ion source, such as brine, in accordance with one embodiment of the present technology. [Diagram 2] FIG. 1 is a schematic system diagram of a controlled extraction and release device in accordance with another embodiment of the present technology. [Diagram 3] FIG. 1 is a schematic top view of a scalable redox membrane platform in accordance with another embodiment of the present technique. [Figure 4] FIG. 1 is a functional block diagram of a lithium ion extraction method using a redox membrane platform according to an embodiment of the present technology. [Diagram 5] FIG. 1 shows an XRD plot of electroplated lithium cobalt oxide on an Al film, showing predominantly (110) crystal plane orientation. [Figure 6] Figure 1 shows a plot of lithium extraction from a saturated lithium sulfate source to a redox membrane. A charge of 1 mAh was passed at a rate of 2 mA cm-2. [Figure 7] Figure 1 shows a plot of lithium release from a lithium cobaltate redox membrane into an aqueous LiOH product. A 1 mAh charge was passed at a rate of 2 mA cm-2. A Pt foil counter electrode was used for both extraction and release. [Figure 8] Figure 13 is a plot showing cyclic voltammetry curves with a lithium cobalt oxide redox film working electrode in 1 M lithium sulfate solution using a 5 mV scan rate with Pt wire and foil reference and counter electrodes, respectively. [Figure 9] FIG. 1 is a schematic diagram of a molten salt bath and spontaneous lithium uptake from the bath (step 1) using a redox membrane according to one embodiment of the present technology. [Figure 10]FIG. 1 is a schematic diagram of lithium released into a non-aqueous solution directly producing Li metal via electrodeposition (step 2). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Referring more specifically to the drawings, for illustrative purposes, systems and methods for lithium ion extraction and fabrication and use of redox membranes are generally shown. Several embodiments of the present technology are generally described in Figures 1-10 to illustrate the properties and functionality of the devices, systems, materials and methods. It will be understood that the methods may vary with respect to the specific steps and sequences, and the systems and devices may vary with respect to structural details, without departing from the basic concepts disclosed herein. The method steps are merely illustrative of the order in which these steps may be performed. The steps may be performed in any order desired so as to still accomplish the objectives of the claimed technology.

[0032] Turning now to Figure 1, the general structure of one apparatus and system 10 for extracting lithium from a liquid source using redox membranes is shown generally. The apparatus of system 10 is a vessel 12 comprising a first counter-current electrode, such as an anode 14, and a second counter-current electrode, such as a cathode 16. The two counter-current electrodes 14, 16 and the redox membrane 18 are electrically coupled to a current source 28 (e.g., a current-applying galvanostat) that comprises circuitry for providing a controllable potential to the electrodes and membranes. The electrodes 14, 16 are preferably high surface area electrodes, typically carbon sheets, embedded with efficient water splitting electrocatalysts, such as platinum or palladium nanoparticles.

[0033] The vessel 12 is separated into two compartments with a wall of a non-porous redox membrane 18. The redox membrane 18 is arranged to physically separate the ion extraction source and the ion-deficient solution such that the redox membrane is in contact with both solutions and the denseness of the redox membrane actively prevents the solutions from intermixing. In this illustration, the first compartment 20 has a source of a solution 22 of Li-containing ions provided for extraction. The lithium-containing solution for extraction can be an aqueous solution, an organic solution or a lithium-containing molten salt solution. For example, the solution 22 for extraction can be an aqueous solution or an organic solution, and is an electrolyte with dissolved LiCl, LiOH, Li2CO3, Li2SO4, or LiNO3, LiBr, LiF, or LiI, and combinations thereof.

[0034] The second compartment 24 has a second solution 26. For example, a redox membrane can be used to extract lithium from the lithium-containing solution 20, which is then transferred to pure water in the second compartment 24. However, the second solution 26 can also be an organic solution or a molten salt solution. For example, the system 10 can extract lithium ions from the aqueous solution 22 and transfer the ions to the organic lithium-containing solution 26. Lithium metal can be simultaneously plated onto a metal substrate in an organic medium. Alternatively, lithium extracted from the aqueous solution can be plated onto a metal substrate through a solid electrolyte.

[0035] The redox membrane 18 preferably has a higher selectivity for Li over Na, Mg, Ca, Al and Si ions. + ions. This feature is important because selectivity largely determines the efficiency of separation processes and scaled-up system design. Highly selective membranes are able to selectively separate the primary ions (in this case, Li +) through the membrane while actively blocking the movement of other ions (contaminants, bystander ions) that remain in source liquid 22. Ion selectivity also reduces the number of plant steps / stages required to separate these undesirable ions, thus reducing the capital costs required by system 10.

[0036] A second important feature of the redox membrane 18 is that it blocks solvent migration between the compartments. The redox membrane 18 is a non-porous monolith that does not contain binders or carbon as in conventional battery electrodes, thereby eliminating crossover from the lithium extraction source 22 to the final lithium product. This feature is important because it eliminates the need to rinse the lithium extraction medium between the lithium extraction and lithium release steps. Thus, the lithium extraction process using the membrane eliminates a large portion of the waste stream.

[0037] The redox membrane 18 is stable in caustic and high temperature environments. The redox membrane 18 does not contain additives, eliminating the polymer binder stability issues experienced by conventional membranes known in the art. This allows the redox membrane to operate with a larger number of lithium extraction sources, such as molten salts and geothermal brines, at a variety of temperatures.

[0038] The redox membrane 18 is also preferably a monolithic structure with tunable crystal orientation. In one embodiment, the lithium diffusion channels in the material of the redox membrane can be oriented perpendicular to the lithium extraction source / redox membrane interface in one compartment 22 and the lithium product / redox membrane interface in the other compartment 24. This allows the redox membrane 18 to achieve the highest possible lithium extraction throughput.

[0039] One method of preparing and operating a solvent-blocking, free-standing, and electrochemically active redox film according to the present technology begins with 1) growing the redox film on a substrate via vapor deposition or in a molten salt electroplating bath. In one embodiment, the redox film is grown on a two-dimensional or three-dimensional metal substrate, such as aluminum, copper, steel, titanium, platinum, gold, silver, etc. In another embodiment, the redox film is grown on a two-dimensional or three-dimensional carbon substrate. In another embodiment, the carbon substrate is coated or impregnated with a metal, such as aluminum, copper, steel, titanium, platinum, gold, silver, etc.

[0040] 2) The substrate is then removed from the deposited redox film to expose both sides of the film. For example, the substrate can be removed from the redox film by mechanical, laser or chemical ablation.

[0041] 3) The redox membrane is then annealed to close the pores and obtain a solvent blocking material. The resulting membrane is ready for use as a redox membrane in a separation and concentration device such as an H-cell device as shown in Figure 1.

[0042] In another embodiment, the redox membrane is unsupported and is fabricated by electrodeposition from a molten salt mixture and may be free-standing or essentially supported.

[0043] In a further embodiment, the redox membrane is supported in the form of an electronically conducting material such as a metal mesh or metal foam, or a carbon-based material such as carbon felt, carbon foam, or porous carbon.

[0044] Alternatively, LCO redox membranes can be fabricated by sintering LCO powder at temperatures above 750°C and high pressures (above 10 MPa) and fabricated as dense, non-porous sintered oxide sheets (typically in the range of 10-500 microns) fabricated with or without a conductive scaffold or framework.

[0045] Generally, in conventional H-type cell testing, the membrane separating the two solutions does not participate in the electrochemical reaction, and the electrical circuit does not connect to the solvent blocking membrane. In contrast, as shown in FIG. 1, during operation, electrical connections are made alternately between the redox membrane 18 and each electrode 14, 16 through contacts 30. Two open circuit elements are shown in this illustration to emphasize the two-stage sequential operation of the H-type cell structure with redox membrane. In a first step, the left solution circuit (circuit 1) is closed to establish an electrical connection with contacts 30, while the right connection (circuit 2) is left open. An applied current in (circuit 1) results in lithium ion flow from the lithium-dilute source solution to the redox membrane. In a second step, the left solution circuit (circuit 1) is opened and the right circuit (circuit 2) is closed. A spontaneous current is allowed to flow in (circuit 2), resulting in lithium ions (i.e., Li release) from the redox membrane to the lithium-enriched product solution. This two-step process can be carried out indefinitely to extract and produce purified lithium products containing high concentrations of Li (e.g., 20-30% LiOH solution).

[0046] Functionally, the two-step process shown in Figure 1 is applied sequentially during redox membrane operation. The first step involves ion uptake into the redox membrane 18 from an ion extraction source 22 in the first compartment 20. This is achieved by passing a current between the redox membrane 18 and the electrode 14. Using lithium cobalt oxide as the redox membrane material as an example and Li2SO4 solution as the lithium extraction source, the two half-reactions to form the redox couple are shown below: Redox membrane half-reactions Li 1-x CoO2+xe - +xLi + → LiCoO2 Counter electrode half reaction x / 2H2O → xe - +xH + +x / 4O2

[0047] These half-reactions proceed until the redox membrane 18 is saturated or partially filled with lithium. Using LiOH as the desired lithium product in this example, passing a current between the redox membrane 18 and another electrode 16 in a second solution 26 results in the release of lithium to its product form. The redox couples for these half-reactions are shown below: Redox membrane half-reactions LiCoO2→ Li 1-x CoO2+xe - +xLi + Cl - → Cl2(g)+xe - Counter electrode half reaction x / 4O2+x / 4H2O+xe - → xOH - Li + +OH - +H2O → LiOH.H2O (aqueous solution)

[0048] These half-reactions proceed until the redox membrane 18 is depleted of lithium ions. During operation of the redox membrane 18, the lithium uptake and lithium release electrochemical steps occur continuously and indefinitely. Thus, this exemplary direct lithium extraction method is capable of extracting lithium from a variety of lithium-containing solutions and producing a higher quality lithium product (i.e., having a higher Li content than is present in the ion extraction source) without additional processing steps.

[0049] A system for extracting lithium from a liquid lithium solution using a controlled process is shown diagrammatically in Figure 2. The system provides control functions through a controller or processor 34 using software. The controller / processor 34 is electrically coupled to a current source 36, with the electrodes and membrane in contact through a circuit 38. The controller / processor 34 is configured to control the operation, duration and characteristics of the output of the current source, electrodes and redox membrane of the extraction and release device 46.

[0050] The controller / processor 34 also controls the distribution or removal of solution source 42 to the compartments of the device 46 through controllable solution inputs and outputs 44 in this embodiment.

[0051] In one embodiment, a large-scale electrode 48 design for increasing process throughput is shown in FIG. 3. The design consists of a conductive frame 50 that can be filled with multiple redox membranes 52 of smaller area. Several of these larger electrodes can then be stacked in series to process large volumes of Li-containing feed solution to produce Li-enriched product solution. This large-scale electrode 48 design provides improved process throughput (i.e., throughput). A non-porous redox membrane slab 52, such as lithium cobalt oxide, is fabricated to fit into the redox membrane insertion site, and the membrane and electrode frame are sealed around the periphery to provide a large, leak-free redox membrane. Similar to the operation of a single redox membrane slab, the lithium-dilute source solution will flow in parallel on one side of the large redox membrane. The lithium-enriched product solution will flow on the other side of the large membrane.

[0052] Turning now to Figure 4, functional block diagrams of three related methods (A, B and C) 100 for membrane-mediated lithium ion extraction from a liquid source for release into aqueous, organic or solid electrolyte media are generally shown. In block 110, lithium-containing brine solutions or aqueous lithium solutions of various available concentrations are prepared. The lithium ion source material provided in block 110 can come from solvated ores, recycled battery materials or natural lithium brine sources, etc.

[0053] Lithium ions are generally extracted in block 120 from a lithium source obtained in block 110 using a redox membrane as shown in the first half-reaction set above and circuit 1 in FIG.

[0054] The lithium extracted from the membrane in block 120 is then released from the redox membrane into a second aqueous solution in block 130, as shown in the second half-reaction set above and application of Circuit 2 in Figure 1. In this illustration, the lithium is released into the second solution in the form of LiOH. In one embodiment, the second solution can be, for example, pure water or an existing solution containing LiOH.

[0055] In alternative method B shown in FIG. 4, lithium is similarly extracted from the lithium source obtained in block 110 using a redox membrane in block 140. However, the lithium is released from the membrane into an organic solution in block 150 using circuit 2 of FIG. 1 to enrich the lithium in the organic solution rather than in the aqueous solution. The concentrated organic or aqueous solution can be further processed to obtain other desirable lithium-containing molecules. For example, the recovered lithium can be converted to Li-containing products such as inorganic and organic lithium salts, prelithiated or lithium-containing battery materials, and lithium metal. In one embodiment, lithium metal is simultaneously plated onto a metal substrate in an organic medium.

[0056] In another alternative method C shown in Figure 4, lithium is extracted from a source material using a redox membrane at block 160. The extracted lithium is transported through a solid electrolyte at block 170, after which the lithium is plated onto a current collector at block 180. Thus, in this embodiment, lithium extracted from an aqueous solution or brine can be ultimately plated through the solid electrolyte onto a metal substrate.

[0057] In another embodiment of method C, an LCO redox membrane for lithium metal plating can be designed in a continuous R2R process. For example, a metal substrate can be transferred into the organolithium-containing electrolyte produced in block 170, plated with lithium metal in block 180, and then transferred out of the electrolyte.

[0058] In another example, a metal substrate can be laminated to a solid electrolyte, and then lithium is plated in between the metal substrate and the solid electrolyte in a single deposition process to form a lithium anode / solid electrolyte composite.

[0059] Alternatively, the solid electrolyte can be coated onto the redox membrane. A metal substrate is then moved into contact with the redox membrane / solid electrolyte assembly. The redox membrane / solid electrolyte assembly can be shaped in a variety of geometric formats to facilitate intimate contact between the redox membrane and the solid electrolyte to provide uniform current distribution during electroplating.

[0060] The plating method can also be adapted to enhance the performance of lithium-ion batteries by prelithiating the anode with lithium. For example, LCO redox membranes are used to extract lithium from a lithium-containing aqueous solution and release it into an organic lithium-containing electrolyte. Lithium can be simultaneously deposited on the lithium-ion battery anode material and transferred into or out of the organic solution in either a batch or R2R process.

[0061] Thus, stable, ion-selective, solvent-blocking redox membrane structures and methods of use are provided. The features of the redox membranes enable extraction from lithium extraction sources such as molten salts and geothermal brines at higher lithium extraction throughput and lower cost compared to conventional extraction methods.

[0062] The technology described herein can be better understood with reference to the accompanying examples, which are for illustrative purposes only and should not be construed as limiting the scope of the technology described herein, as defined in the appended claims. EXAMPLES

[0063] To demonstrate the working principle of this technology, an LCO lithium-ion extracted redox film was fabricated and tested. In this example, lithium cobalt oxide (LiCoO2) was prepared by electrodeposition onto the electrode and evaluated.

[0064] A mixture of 0.75 g LiOH and 8 g KOH was ground and placed in a nickel crucible. After heating to 350 °C, about 0.5 g CoO was added to the melt. The color of the melt changed from white to blue as the divalent cobalt ions were coordinated by hydroxide ions. After the added CoO was completely dissolved, an aluminum foil was inserted into the bath for LiCoO2 deposition.

[0065] For a pure (110) orientation, 20 mA / cm 2 Pulses of 0.01 V were applied for 2 seconds with 5 seconds rest between pulses. 700 on / off cycles were used to produce electrodes with a loading of 4 mAh / cm2 and a thickness of 60 μm. Higher loading samples (120 μm and 240 μm) were produced by increasing the number of pulses to 1,400 and 2,800, respectively.

[0066] XRD of lithium cobalt oxide electroplated on Al was performed and FIG. 5 shows a predominantly (110) crystal plane orientation, which is the fast Li ion diffusion direction.

[0067] An H-type electrochemical cell was used with the prepared LCO redox membrane to demonstrate and test the capability of Li separation. An H-type cell was assembled using a (110) faceted LCO redox membrane that physically separates two solutions. One solution was filled with a saturated solution of Li2SO4, while the other solution contained 0.1 M LiOH. Platinum foil and platinum wire were used as the reference and counter electrodes, respectively. 2 mA cm -2 A current density of 1000 mA was passed through the LCO redox membrane, which absorbed lithium from the Li2SO4 solution (a) and released lithium into the LiOH solution (b).

[0068] Lithium extraction from a saturated lithium sulfate source into the redox membrane is shown in Figure 6, and lithium release from the lithium cobaltate redox membrane into the aqueous LiOH product is shown in Figure 7. A charge of 1 mAh was then applied at 2 mA cm -2 A Pt foil counter electrode was used for both extraction and release. EXAMPLES

[0069] As another illustration, electrochemical data was obtained using a second H-type cell. The H-type cell was assembled using a (110) faceted LCO redox membrane that physically separates the two solutions. One solution was filled with a saturated solution of Li2SO4, while the other solution contained 0.1 M LiOH. Platinum foil and platinum wire were used as the reference and counter electrodes, respectively. The voltage was swept from -2 volts to 2 volts using a scan rate of 5 mV, with the scan sweep starting in the positive voltage direction. The oxidation / reduction peak current of the LCO redox membrane can be seen near the 1 volt line.

[0070] Cyclic voltammetry curves using the lithium cobalt oxide redox membrane working electrode in 1 M lithium sulfate solution in compartment (a) at a 5 mV scan rate with Pt wire and foil reference and counter electrodes, respectively, are shown in FIG. EXAMPLES

[0071] To further demonstrate the capabilities of the redox membrane and separation technology, an LCO lithium ion extraction redox membrane was fabricated and tested in a molten salt bath separation context. In this illustration, lithium metal was electrodeposited in a two-step process. Step 1, shown in Figure 9, shows lithium uptake from a molten salt bath, and step 2, shown in Figure 10, shows lithium release via electrodeposition into a non-aqueous solution directly producing Li metal.

[0072] In step 1, LCO on Al electrodes was prepared using a molten salt electroplating system. These LCO on Al electrodes were stamped into circular disks and assembled into CR 2025 coin cells with polymer separators, liquid organic electrolyte, and Li chip counter / reference electrodes. A potentiostat was then utilized to convert the LCO from the LiCoO2 initial state to Li 0.5 The lithium was removed from the CoO2 state. The lithium-depleted Li 0.5 The CoO2 electrode was immersed in a lithium-containing molten salt bath (step 1) for 10 min.

[0073] After 10 min, the immersed LCO electrode was removed from the molten salt, washed, and reassembled into a new CR 2025 coin cell with a polymer separator, liquid organic electrolyte, and Li-tip counter / reference electrodes. Delithiation of this molten-salt-treated LCO in a CR 2025 coin cell demonstrated that the initially delithiated LCO was spontaneously relithiated (step 2) in the molten salt system.

[0074] From the description herein, it will be understood that the present disclosure encompasses multiple embodiments, including, but not limited to, the following:

[0075] 1. A polymer-free redox membrane composition for lithium extraction, comprising: (a) a plate of a non-porous electrochemically active lithium transition metal oxide; (b) the plate is solvent impermeable; (c) the plate is configured to preferentially select lithium ions over other ions; and (d) the plate is active and stable at room temperature, 20-30°C, but also active and stable at elevated temperatures, 60°C-200°C.

[0076] The composition of any of the preceding or following implementations, wherein the redox film comprises plates of LiCoO2 (LCO).

[0077] The composition of any of the preceding or following implementations, wherein the LCO redox film comprises a film of sintered packed LCO powder.

[0078] The composition of any of the preceding or following implementations, wherein the LCO redox film comprises a film in a layered R3-m space group having a (110) crystallographic orientation.

[0079] The composition of any of the preceding or following implementations, wherein the plate further comprises at least one electrical contact coupled to the plate.

[0080] An apparatus for lithium ion extraction comprising: (a) a redox membrane having a first active surface on a first side, and a second active surface on a second side, and one or more electrical contacts; (b) a container having an interior separated into a first compartment and a second compartment by the redox membrane; (c) at least one electrode in the first compartment and at least one counter electrode in the second compartment of the container; and (d) a current source electrically coupled to the electrodes and the redox membrane.

[0081] An apparatus as described in any of the preceding or following implementations, further comprising a controller having an electrical circuit electrically coupled to the current source, the electrodes, and the redox membrane; the controller configured to control the actuation, duration, and characteristics of the current applied to the electrodes and the redox membrane.

[0082] An apparatus as described in any of the preceding or following implementations, further comprising at least one solution source and one or more solution inputs fluidly coupled to at least one of the compartments of the container; and one or more solution outputs fluidly coupled to at least one compartment of the container; capable of introducing solution into the at least one compartment through the inputs; and capable of removing solution from the at least one compartment through the outputs.

[0083] An apparatus as described in any of the preceding or following implementations, further comprising a controller operably coupled to the fluid input and output, the controller configured to control the flow of the first solution and the second solution into and out of the compartment through the fluid input and output.

[0084] The LCO redox membrane is 2+ , Mg 2+ , Ca 2+ , Zn 2+ , Sr 2+ , B.A. 2+ , Al 3+ and Si 4+ The apparatus of any of the preceding or following implementations selects Li ions over one or more positively charged ions (cations) of the group of ions.

[0085] The LCO redox membrane is - , Br - and SO4 -2 The apparatus of any of the preceding or following implementations selects Li ions in the presence of one or more negatively charged ions (anions) from the group consisting of:

[0086] An apparatus of any of the preceding or following implementations, further comprising a membrane current collector slab coupled to a current source; and multiple redox membranes electrically coupled in series or parallel to the slab to allow greater throughput or solution volumes to be processed.

[0087] 1. A method for extracting lithium from a liquid source, the method comprising: (a) providing a first solution of one or more lithium-containing salts; (b) extracting Li-ions from the solution using a LCO redox membrane; and (c) releasing the extracted Li-ions from the LCO redox membrane into a second solution.

[0088] The method of any of the preceding or following implementations, further comprising converting the lithium ions released into the second solution into a product selected from the group of inorganic lithium salts, organic lithium salts, and lithium metal.

[0089] The method of any of the preceding or following implementations, wherein the first solution of lithium-containing salts comprises one or more salts selected from the group of LiCl, LiOH, Li2CO3, Li2SO4, LiNO3, LiBr, LiF, and LiI.

[0090] The method of any of the preceding or following implementations, wherein the first solution of a lithium-containing salt comprises a Li-ion containing organic solution.

[0091] The method of any of the preceding or following implementations, wherein the first solution of the lithium-containing salt comprises an aqueous solution and the second solution comprises an organic solution.

[0092] The method of any of the preceding or following implementations, further comprising: placing a metal substrate in a second solution; and plating lithium metal onto the substrate.

[0093] 1. A system for extracting lithium from a liquid lithium solution, comprising: (a) a separation device comprising: (i) one or more redox membranes having a first active surface on a first side, and a second active surface on a second side, and one or more electrical contacts; (ii) a container having an interior separated into two compartments by each redox membrane; (iii) at least one electrode in one compartment of the container and at least one counter electrode in the other compartment; (iv) a current source electrically coupled to the electrodes and the redox membrane; (b) a processor configured to control the current source, the electrodes, and the redox membrane; and (c) a non-transitory memory storing instructions executable by the processor; and (d) the instructions, when executed by the processor, perform the steps of: (i) providing a solution of one or more lithium-containing salts; (ii) extracting Li-ions from the solution using the one or more redox membranes; and (iii) releasing the extracted Li-ions from the one or more redox membranes into a second solution; and (e) processing the released Li-ions from the second solution.

[0094] The system of any of the preceding or following implementations, wherein processing the released Li-ions includes converting the lithium ions released in the second solution to a product selected from the group of inorganic lithium salts, organic lithium salts, and lithium metal.

[0095] A system as described in any of the preceding or following implementations, wherein the processor and instructions are configured to control the actuation, duration and characteristics of the current applied to the electrodes and the one or more redox membranes.

[0096] The system of any of the preceding or following implementations, wherein the redox membrane of the device of the system comprises a plate of LiCoO2 (LCO).

[0097] As used herein, the term "embodiment" is intended to include, but not be limited to, an embodiment, example, or other form of implementing the technology described herein.

[0098] As used herein, the singular terms "a," "an," and "the" can include plural referents unless the context clearly dictates otherwise. Reference to a singular referent is not intended to mean "only one," unless expressly stated, but rather means "one or more."

[0099] Within this disclosure, a construct such as "A, B, and / or C" describes when either A, B, or C can be present, or any combination of the items A, B, and C. A construct such as "at least one of" followed by a group listing elements indicates that at least one of the group elements is present, including, where applicable, any possible combination of the listed elements.

[0100] References in this disclosure to "an embodiment," "at least one embodiment," or similar embodiment language indicate that a particular feature, structure, or characteristic described in connection with the described embodiment is included in at least one embodiment of the disclosure. Thus, these various embodiment phrases are not necessarily all referring to the same embodiment or to a specific embodiment that differs from all other embodiments described. The embodiment phrases should be interpreted to mean that the particular features, structures, or characteristics of a given embodiment can be combined in any suitable manner in one or more embodiments of the disclosed devices, systems, or methods.

[0101] As used herein, the term "set" refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.

[0102] Relative terms such as first and second, top and bottom, and the like may be used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any actual such relationship or order between such entities or operations.

[0103] The terms "comprises," "comprising," "has," "having," "includes," "including," "contains," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, or contains a list of elements may not only not include those elements, but may also include other elements that are not expressly listed or that are inherent to such process, method, article, or apparatus. An element following "comprises," "having," "including," or "containing" does not, without further constraints, preclude the presence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, or contains that element.

[0104] As used herein, the terms "generally", "approximately", "substantially" and "about" or other versions thereof are used to describe and explain small variations. When used in conjunction with an event or circumstance, the term can refer to not only when the event or circumstance occurs exactly, but also when the event or circumstance occurs in close approximation. When used in conjunction with a numerical value, the term can refer to a range of variation of ±10% or less of the numerical value, such as ±5% or less, ±4% or less, ±3% or less, ±2% or less, ±1% or less, ±0.5% or less, ±0.1% or less, or ±0.05% or less. For example, "substantially" aligned can refer to an angle variation of ±10° or less, such as ±5° or less, ±4° or less, ±3° or less, ±2° or less, ±1° or less, ±0.5° or less, ±0.1° or less, or ±0.05° or less.

[0105] Furthermore, amounts, ratios, and other numerical values ​​may sometimes be presented in the form of a range herein. Such range formats are used for convenience and brevity, and should be understood flexibly to include numerical values ​​explicitly specified as the limits of the range, but also to include all individual numerical values ​​or subranges contained within the range, as if each numerical value and subrange were explicitly specified. For example, a ratio range of about 1 to about 200 should be understood to include the explicitly recited range of about 1 to about 200, but also to include individual ratios such as about 2, about 3, and about 4, and subranges such as about 10 to about 50, about 20 to about 100, etc.

[0106] The term "coupled," as used herein, is defined as connected, but not necessarily directly, and not necessarily mechanically. Devices or structures that are "configured" in a particular way are at least so configured, but may be configured in other ways not recited.

[0107] Benefits, advantages, solutions to problems, and any element or elements that may cause or make any benefit, advantage, or solution more pronounced are not to be construed as critical, required, or essential features or elements of the technology described herein or any or all of the claims.

[0108] Additionally, in the foregoing disclosure, various features may be grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Inventive subject matter may lie in less than all features of a single disclosed embodiment.

[0109] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

[0110] It will be understood that some jurisdictions may require the deletion of one or more portions of the present disclosure after the application has been filed. Therefore, the reader should refer to the application as filed for the original content of the present disclosure. Any deletion of the content of the present disclosure should not be construed as an abandonment, loss, or contribution to the public of any subject matter of the application as originally filed.

[0111] The following claims are hereby incorporated into this disclosure, with each claim standing on its own as separately claimed subject matter.

[0112] Although the description herein contains many details, these should not be construed as limiting the scope of the disclosure, but merely providing examples of some presently preferred embodiments, and therefore, it should be recognized that the scope of the disclosure encompasses all other embodiments that may become apparent to those skilled in the art.

[0113] All structural and functional equivalents to elements of the disclosed embodiments known to one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, any element, component, or method step not present in the disclosure is intended to be publicly disclosed, regardless of whether the element, component, or method step is expressly recited in the claims. No claim element in this application should be construed as a "means-plus-function" claim unless the element is expressly recited using the phrase "means for." No claim element in this application should be construed as a "step-plus-function" claim unless the element is expressly recited using the phrase "step for."

Claims

1. 1. A polymer-free redox film composition for lithium extraction, comprising: (a) a non-porous electrochemically active lithium transition metal oxide plate; Including; (b) the plate is solvent impermeable; (c) the plates are configured to preferentially select lithium ions over other ions; (d) the plate is active and stable at room temperature, 20-30°C, but is also active and stable at elevated temperatures, 60°C to 200°C; composition.

2. The redox film is LiCoO ２ The composition of claim 1 comprising a plate of (LCO).

3. The composition of claim 2 , wherein the LCO redox film comprises a film of sintered packed LCO powder.

4. 3. The composition of claim 2, wherein the LCO redox film comprises a film in a layered R3-m space group having a (110) crystallographic orientation.

5. The composition of claim 1 , wherein the plate further comprises at least one electrical contact coupled to the plate.

6. 1. An apparatus for lithium ion extraction comprising: (a) a redox membrane having a first active surface on a first side, and a second active surface on a second side, and one or more electrical contacts; (b) a vessel having an interior separated into a first compartment and a second compartment by said redox membrane; (c) at least one electrode in the first compartment and at least one counter electrode in the second compartment of the vessel; (d) a current source electrically coupled to the electrode and the redox membrane; An apparatus comprising:

7. a controller having an electrical circuit electrically coupled to the current source, the electrodes, and the redox membrane; Further comprising: the controller is configured to control the actuation, duration and characteristics of the current applied to the electrodes and the redox membrane; 7. The apparatus of claim 6.

8. at least one solution source and one or more solution inputs fluidly coupled to at least one of said compartments of said vessel; one or more solution outputs fluidly coupled to at least one compartment of the vessel; Further comprising: A solution can be introduced into at least one compartment through said input; A solution can be removed from at least one compartment through said output.

7. The apparatus of claim 6.

9. a controller operably coupled to the fluid input and output; 9. The device of claim 8, further comprising: a controller configured to control flow of first and second solutions into and out of the compartment through the fluid inputs and outputs.

10. The LCO redox membrane is ２＋ , Mg ２＋ , Ca ２＋ , Zn ２＋ , Sr ２＋ , Ba ２＋ , Al ３＋ and Si ４＋ 7. The apparatus of claim 6, wherein Li ions are selected over one or more positively charged ions (cations) of the group of ions.

11. The LCO redox membrane is － , B － and S.O. ４ ２－ 7. The apparatus of claim 6, wherein the Li ion is selected in the presence of one or more negatively charged ions (anions) from the group consisting of:

12. a membrane current collector slab coupled to a current source; a plurality of redox membranes electrically coupled to the slab in series or parallel to allow a larger throughput or solution volume to be processed; The apparatus of claim 6 further comprising:

13. 1. A method for extracting lithium from a liquid source, comprising the steps of: (a) providing a first solution of one or more lithium-containing salts; (b) extracting Li ions from the solution using a LCO redox membrane; (c) releasing the extracted Li ions from the LCO redox membrane into a second solution; and The method includes:

14. converting the lithium ions released in said second solution into a product selected from the group consisting of inorganic lithium salts, organic lithium salts and lithium metal. The method of claim 13 further comprising:

15. The first solution of lithium-containing salts is LiCl, LiOH, Li ２ CO ３ , Li ２ SO ４ , LiNO ３ 14. The method of claim 13, comprising one or more salts selected from the group consisting of LiBr, LiF and LiI.

16. 14. The method of claim 13, wherein the first solution of a lithium-containing salt comprises a Li-ion containing organic solution.

17. 14. The method of claim 13, wherein the first solution of the lithium-containing salt comprises an aqueous solution and the second solution comprises an organic solution.

18. placing a metal substrate in the second solution; plating lithium metal onto the substrate; The method of claim 13 further comprising:

19. 1. A system for extracting lithium from a liquid lithium solution, comprising: (a) (i) one or more redox membranes having a first active surface on a first side, and a second active surface on a second side, and one or more electrical contacts; (ii) a vessel having an interior separated into two compartments by each of said redox membranes; (iii) at least one electrode in one compartment and at least one counter electrode in the other compartment of the vessel; (iv) a current source electrically coupled to the electrode and the redox membrane; A separation device comprising: (b) a processor configured to control the current source, the electrodes, and the redox membrane; (c) a non-transitory memory that stores instructions executable by the processor; and With (d) the instructions, when executed by the processor, (i) providing a solution of one or more lithium-containing salts; (ii) extracting Li-ions from the solution using the one or more redox membranes; (iii) releasing the extracted Li-ions from the one or more redox membranes into a second solution; and performing steps including: (e) processing the released Li ions from the second solution.

20. Processing the released Li ions includes: converting the lithium ions released in said second solution into a product selected from the group consisting of inorganic lithium salts, organic lithium salts and lithium metal.

20. The system of claim 19, comprising:

21. 20. The system of claim 19, wherein the processor and instructions are configured to control the actuation, duration and characteristics of electrical current applied to the electrodes and the one or more redox membranes.

22. The redox membrane of the device of the system is LiCoO ２ 20. The system of claim 19, comprising a plate of (LCO).

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