Process and device for the electrolysis of lithium brines

Abstract

The present disclosure relates to processes and devices for the production of lithium hydroxide using electrolysis.

Description

[0001] Process and device for the electrolysis of lithium brines

[0002] Field of the invention

[0003] The present disclosure relates to processes and devices for the production of lithium hydroxide using electrolysis.

[0004] Background

[0005] The demand for lithium hydroxide is growing rapidly. The market for lithium hydroxide is expanding and the current world production capacity will likely not meet the expected increase in demand. For example, lithium hydroxide is used as a carbon dioxide absorbent in the purification of gases and air, as a heat transfer medium, as a storage-battery electrolyte, as a polymerization catalyst, in ceramics, in Portland cement formulations, in manufacturing other lithium compounds and in esterification, especially for making lithium stearate.

[0006] Lithium ion batteries have become the battery of choice in several existing and proposed new applications due to their high energy density to weight ratio, as well as their relatively long useful life when compared to other types of batteries. Lithium ion batteries are used in several applications such as laptop computers, cell phones, medical devices and implants (for example cardiac pacemakers). Lithium ion batteries are also used in automobiles, e.g., hybrid and electric vehicles, which are environmentally friendly because of reduced emissions and decreased reliance on hydrocarbon fuels.

[0007] High purity lithium hydroxide can be prepared from aqueous solutions of lithium salts (lithium brines) using electrolysis of the lithium brine in a membrane cell comprising an ion-selective membrane which is permeable to lithium cations, but prevents anions from diffusing across (cation-exchange membrane). WO 20231281 033 A1 discloses electrolyzing an aqueous solution comprising lithium sulfate at low pH ranges. Also disclosed are processes comprising stripping a liquid medium comprising lithium with an acidic aqueous solution to obtain an aqueous solution comprising lithium, and electrolyzing the aqueous solution comprising lithium. Further disclosed are processes for preparing a liquid medium comprising lithium.

[0008] WO 2015 / 058 287 A1 provides processes comprising submitting an aqueous composition comprising lithium sulfate and / or bisulfate to an electrolysis or an electrodialysis for converting at least a portion of said sulfate into lithium hydroxide. During electrolysis or electrodialysis, the aqueous composition is at least substantially maintained at a pH having a value of about 1 to about 4; and converting said lithium hydroxide into lithium carbonate. Alternatively, lithium sulfate and / or lithium bisulfate can be submitted to a first electromembrane process that comprises a two-compartment membrane process for conversion of lithium sulfate and / or lithium bisulfate to lithium hydroxide, and obtaining a first lithium-reduced aqueous stream and a first lithium hydroxide-enriched aqueous stream; and submitting said first lithium-reduced aqueous stream to a second electromembrane process comprising a three-compartment membrane process to prepare at least a further portion of lithium hydroxide and obtaining a second lithium-reduced aqueous stream and a second lithium-hydroxide enriched aqueous stream.

[0009] WO 2013 / 159 194 A1 discloses methods for preparing lithium hydroxide comprising submitting an aqueous composition comprising lithium sulfate to an electrolysis under conditions suitable for converting at least a portion of said lithium sulfate into lithium hydroxide, wherein during said electrolysis, said aqueous composition comprising lithium sulfate has a pH of greater than 7.

[0010] WO 2010 / 056 322 A1 discloses a method for recovering lithium as lithium hydroxide by feeding an aqueous stream containing lithium ions to a bipolar electrodialysis cell, wherein the cell forms a lithium hydroxide solution. US 2019 / 032227 A1 discloses a lithium hydroxide production process integrating a lithium stripping stage with a lithium hydroxide production process performed in a two-compartment electrolysis cell. The method comprises: (a) providing a two-compartment electrolysis cell having an anode, a cathode, and a membrane barrier disposed therebetween, said membrane barrier being permeable to lithium (Li+) cations and to protons (H+); (b) stripping the lithium- loaded medium by means of an aqueous stripping solution, to extract said lithium cations from the medium into the aqueous stripping solution, producing an aqueous, lithium-containing intermediate solution along with a stripped medium; (c) introducing said aqueous, lithium-containing intermediate solution into an anodic compartment of said two-compartment electrolysis cell, to form an anolyte; (d) introducing an aqueous medium into a cathodic compartment of said two-compartment electrolysis cell to form a catholyte; (e) operating said cell so as to: (i) generate oxygen gas at said anode; (ii) produce said protons (H+) within said anolyte; and (iii) generate hydrogen gas and hydroxide (OH“) at said cathode; and such that a portion of said lithium cations and a portion of said protons traverse said membrane barrier, whereby said protons react with said hydroxide to produce water in said catholyte; (f) removing an aqueous product stream from said cathodic compartment, said product stream containing dissolved lithium hydroxide values; and (g) recycling a discharge stream containing said anolyte, from said anodic compartment, for use in said stripping of the lithium-loaded medium.

[0011] Typical membranes used in electrolysis are polymer materials comprising perfluorinated and polyfluorinated alkyl substances (PFAS), such as sulfonated tetrafluoroethylene-based fluoropolymer-copolymers (e.g., Nation™). During the electrolysis process, other metal hydroxides and / or metal carbonates might be formed, depending on the impurity level of the brine solutions employed. Such metal hydroxides and metal carbonates are likely deposited inside the cationexchange membrane, where pH values range from 0 to 14 across the membrane. Replacing the cation-exchange membrane is expensive and timeconsuming. In order to reduce operational expenditures, a frequent replacement of membranes shall be avoided, and the membrane material should be easily available and procurable at low cost.

[0012] Summary of the invention

[0013] The present invention utilizes end-of-life PFAS membrane(s) in electrochemical cells for the electrolysis of lithium sulfate solutions. The end-of-life membranes are widely available from various industrial electrolysis processes, e.g., the electrolysis of aqueous sodium chloride. The end-of-life membranes can be used without any modification. In some embodiments, spacers are employed in electrochemical cells for lithium sulfate electrolysis, which help to extend the lifetime of cation-exchange membranes. End-of-life membranes are already fully hydrated, while the swelling process of pristine membranes usually takes some time, and electrolyzers need longer to become fully operational.

[0014] Brief description of the drawings

[0015] Fig. 1 shows an exemplary electrolysis cell of the present disclosure,

[0016] Fig. 2 shows electrode temperature vs time plots of long-term test runs of a process and a device of the present disclosure,

[0017] Fig. 3 shows cell voltage vs time plots of long-term test runs of a process and a device of the present disclosure.

[0018] Detailed description

[0019] The present disclosure provides a process for the electrolysis of lithium- containing brines, for instance, aqueous lithium sulfate solutions, in electrochemical cells comprising at least one cation-exchange membrane, wherein the at least one cation-exchange membrane is an end-of-life PFAS membrane.

[0020] The process of the present disclosure comprises i) operating a sulfonated cation-exchange membrane comprising perfluoroalkyl and polyfluoroalkyl substances (PFAS) in an industrial electrolysis process other than the electrolysis of lithium-containing brines for a time period in the range of from 7.500 hours to 30.000 hours to obtain an end-of-life PFAS membrane, and electrolysis of lithium-containing brines in electrochemical cells comprising at least one cation-exchange membrane, wherein the at least one cationexchange membrane is the end-of-life PFAS membrane.

[0021] As used herein, the term “electrolysis” refers to the chemical decomposition produced by passing an electric current through a liquid or solution comprising ions.

[0022] As used herein, the term “about” refers to a ±5% of the stated number. Unless otherwise stated, all numbers are assumed to be modified by “about”.

[0023] In the context of the present disclosure, an "end-of-life PFAS membrane" is a cation-exchange polymer membrane that has already been operated in another industrial electrolysis processes, e.g., the electrolysis of aqueous sodium chloride or aqueous hydrogen chloride, for a time period in the range of from 7.500 hours to 30.000 hours, e.g., from 17.000 hours to 25.000 hours.

[0024] The PFAS membrane is a sulfonated membrane comprising perfluoroalkyl and polyfluoroalkyl substances (PFAS). In some embodiments, the sulfonated membrane has a hydrocarbon backbone or a PTFE backbone. In some embodiments, the sulfonated membrane is made of a sulfonated tetrafluoroethylene based fluoropolymer-copolymer. In some embodiments, the sulfonated membrane is made of a sulfonated polyaryleneether or a polyphenylsulfon, e.g., a polyaryleneether Ultrason® or polyphenylsulfon Ultrason®. In some embodiments, the polymer membrane is at least one chosen from a perfluorinated cation-exchange membrane, a PEEK-reinforced cation-exchange membrane, a PTFE-reinforced cation-exchange membrane, and combinations thereof. In some embodiments, the membrane is made of a fluorinated copolymer with sulfonic acid groups. In some embodiments, the membrane is a perfluorosulfonate polymer membrane. In some embodiments, the perfluorosulfonate polymer membrane is made of a tetrafluoroethylene- perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer (NAFION™ by E.l. du Pont de Nemours).

[0025] The end-of-life membranes are widely available from various industrial electrolysis processes, e.g., the electrolysis of aqueous sodium chloride or aqueous hydrogen chloride. The end-of-life membranes can be used without any modification. End-of-life membranes are already fully hydrated, while the swelling process of pristine membranes usually takes some time, and electrolyzers need longer to become fully operational.

[0026] In some embodiments, the end-of-life PFAS membrane (EOL PFAS membrane) has a thickness in the range of from 380 pm to 420 pm, e.g., from 390 pm to 410 pm, for instance, from 395 pm to 405 pm.

[0027] In some embodiments, the thickness of the EOL PFAS membrane is larger than the thickness of a corresponding pristine PFAS membrane, i.e., of the membrane before operating in the industrial electrolysis process, by a factor in the range of from 1.1 to 1.2, e.g., from 1.1 to 1.15.

[0028] Lithium-containing brines are aqueous solutions comprising lithium. The electrochemical splitting of water will yield hydrogen on the cathode side as well as oxygen on the anode side. Cathode and anode of the electrolysis cell are separated by cation-exchange membrane(s). Under alkaline or pH neutral conditions, hydrogen and hydroxide ions are generated on the cathode. Protons are formed during oxygen formation on the anode side. During electrolysis of brines, lithium-ions migrate from the anolyte through the cation-exchange membrane into the catholyte.

[0029] In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 5 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 30 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 40 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 50 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 60 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 70 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 80 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 90 g / L to about 100 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 90 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 80 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 70 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 60 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 50 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 40 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 20 g / L to about 30 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 30 g / L to about 90 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 40 g / L to about 80 g / L. In some embodiments, the aqueous solution comprising lithium has a concentration of lithium ranging from about 50 g / L to about 70 g / L.

[0030] A person skilled in the art would appreciate that various reaction parameters, will vary depending on a number of factors, such as the nature of the starting materials, their level of purity, the scale of the reaction as well as all the parameters since they can be dependent from one another, and could adjust the reaction conditions accordingly to optimize yields.

[0031] In some embodiments, the process uses a current density ranging from 0.05 A / cm2to 2.0 A / cm2, e.g., from 0.1 A / cm2to 1 A / cm2, for instance, from 0.3 A / cm2to 1 A / cm2, or from 0.4 A / cm2to 0.9 A / cm2.

[0032] In some embodiments, the process uses a voltage ranging from 0 V to 10 V, e.g., from 0 V to 8 V, for instance, from 3 V to 7 V, or from 5.5 V to 6.5 V.

[0033] In some embodiments of the process, the aqueous solution comprising lithium has a temperature ranging from 20°C to 95°C, e.g., from 30°C to 90°C, for instance, from 40°C to 85°C, or from 40°C to 60°C.

[0034] According to one aspect, the present disclosure provides a process for preparing lithium hydroxide, the process comprising submitting an aqueous composition comprising a lithium compound to electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide.

[0035] In some embodiments of the process, the pH value of the aqueous composition comprising a lithium compound is in the range of from 2 to 12.

[0036] In some embodiments, the process comprises submitting an aqueous composition comprising lithium sulfate to electrolysis under conditions suitable for converting at least a portion of the lithium sulfate into lithium hydroxide, wherein during the electrolysis, the anolyte has a pH of less than 7, and the catholyte has a pH of greater than 7.

[0037] In some embodiments, the process comprises submitting an aqueous composition comprising lithium sulfate to electrolysis under conditions suitable for converting at least a portion of the lithium sulfate into lithium hydroxide, wherein during the electrolysis, the anolyte has a pH in the range of from 0 to 7, and the catholyte has a pH in the range of from 7 to 15.

[0038] According to another aspect, there is provided a process for preparing lithium hydroxide, the process comprising leaching an acid roasted lithium-containing material with water so as to obtain an aqueous composition comprising Li+and at least one metal ion; reacting the aqueous composition comprising Li+and the at least one metal ion with a base so as to obtain a pH of about 4.5 to about 6.5 and thereby at least partially precipitating the at least one metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising the at least one hydroxide and an aqueous composition comprising Li+and having a reduced content of the at least one metal ion, and separating the aqueous composition from the precipitate; contacting the aqueous composition comprising Li+and having a reduced content of the at least one metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from the composition, thereby obtaining an aqueous composition comprising a lithium compound; and submitting the aqueous composition comprising the lithium compound to an electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide.

[0039] According to another aspect, there is provided a process for preparing lithium hydroxide, the process comprising leaching a base-baked lithium-containing material with water so as to obtain an aqueous composition comprising Li+and at least one metal ion; reacting the aqueous composition comprising Li+and the at least one metal ion with a base so as to obtain a pH of about 4.5 to about 6.5 and thereby at least partially precipitating the at least one metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising the at least one hydroxide and an aqueous composition comprising Li+and having a reduced content of the at least one metal ion, and separating the aqueous composition from the precipitate; optionally reacting the aqueous composition comprising Li+and having the reduced content of the at least one metal ion with another base so as to obtain a pH of about 9.5 to about 11.5, and with optionally at least one metal carbonate, thereby at least partially precipitating at least one metal ion optionally under the form of at least one carbonate so as to obtain a precipitate optionally comprising the at least one carbonate and an aqueous composition comprising Li+and having a reduced content of the at least one metal ion, and separating the aqueous composition from the precipitate; contacting the aqueous composition comprising Li+and having a reduced content of the at least one metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from the composition, thereby obtaining an aqueous composition comprising a lithium compound; and submitting the aqueous composition comprising the lithium compound to an electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide.

[0040] The processes of the present disclosure can be effective for treating various lithium-containing materials. The lithium-containing material can be a lithium- containing ore, a lithium compound, or a recycled industrial lithium-containing entity. For example, the lithium-containing ore can be, for example, a- spodumene, [3-spodumene, lepidolite, pegmatite, petalite, eucryptite, amblygonite, hectorite, smectite, clays, or mixtures thereof. The lithium compound can be, for example, LiCI, Li2SO4, LiHCOs, Li2CO3, LiNO3, LiC2H3O2(lithium acetate), LiF, lithium stearate or lithium citrate. The lithium-containing material can also be a recycled industrial lithium-containing entity such as lithium ion batteries, other lithium products or derivatives thereof.

[0041] In some embodiments, the aqueous solution comprising lithium is obtained by leaching a lithium containing ore.

[0042] In other embodiments, the aqueous solution comprising lithium is lithium containing ground water.

[0043] In yet other embodiments, the aqueous solution comprising lithium is obtained by a process comprising: mechanically comminuting at least one chosen from a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and combinations thereof to obtain a black mass, and leaching the black mass to obtain an aqueous solution comprising lithium.

[0044] Black Mass:

[0045] “Black mass” refers to materials comprising lithium derived from, for example, a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and / or combinations thereof by mechanical processes such as mechanical comminution. For example, black mass may be derived from battery scrap by mechanically treating the battery scrap to obtain the active components of the electrodes such as graphite and cathode active material and may include impurities from the casing, electrode foils, cables, separator, and electrolyte. In some examples, the battery scrap may be subjected to a heat treatment to pyrolyze organic (e.g., electrolyte) and polymeric (e.g., separator and binder) materials. Such a heat treatment may be performed before or after mechanical comminution of the battery material.

[0046] Lithium ion batteries may be disassembled, punched, milled, for example in a hammer mill, and / or shredded, for example in an industrial shredder. From this kind of mechanical processing the active material of the battery electrodes may be obtained. A light fraction such as housing parts made from organic plastics and aluminum foil or copper foil may be removed, for example, in a forced stream of gas, air separation or classification.

[0047] Battery scraps may stem from, e.g., used batteries or from production waste such as off-spec material. In some embodiments a battery material is obtained from mechanically treated battery scraps, for example from battery scraps treated in a hammer mill or in an industrial shredder. Such material may have an average particle diameter (D50) ranging from 1 pm to 1 cm, such as from 1 to 500 pm, and further for example, from 3 to 250 pm.

[0048] Larger parts of the battery scrap like the housings, the wiring and the electrode carrier films may be separated mechanically such that the corresponding materials may be excluded from the battery material that is employed in the process.

[0049] Mechanically treated battery scrap may be subjected to a solvent treatment in order to dissolve and separate polymeric binders used to bind the transition metal oxides to current collector films, or, e.g., to bind graphite to current collector films. Suitable solvents are N-methylpyrrolidone, N,N-dimethyl- formamide, N,N-dimethylacetamide, N-ethylpyrrolidone, and dimethylsulfoxide, in pure form, as mixtures of at least two of the foregoing, or as a mixture with 1 % to 99 % by weight of water.

[0050] Mechanically treated battery scrap may be subjected to a heat treatment in a wide range of temperatures under different atmospheres. The temperature range is usually in the range of 100°C to 900°C. Lower temperatures below 300°C may serve to evaporate residual solvents from the battery electrolyte, at higher temperatures the binder polymers may decompose while at temperatures above 400°C the composition of the inorganic materials may change as some transition metal oxides may become reduced either by the carbon contained in the scarp material or by introducing reductive gases. In some embodiments, a reduction of lithium metal oxides may be avoided by keeping the temperature below 400°C and / or by removing carbonaceous materials before the heat treatment.

[0051] In some embodiments, the battery material comprises at least one chosen from lithiated nickel cobalt manganese oxide, lithiated nickel cobalt aluminum oxide, lithium metal phosphate, lithium ion battery scrap, black mass derived from a lithium ion battery, and combinations there.

[0052] In some embodiments, the battery material comprises lithium metal phosphate of formula LixMPC , wherein x is an integer greater than or equal to one, and M is chosen from metals, transition metals, rare earth metals, and combinations thereof. In some embodiments, the battery material comprises lithiated nickel cobalt manganese oxide of formula Lii+x(NiaCObMncM1d )i-xO2, wherein M1 is chosen from Mg, Ca, Ba, Al, Ti, Zr, Zn, Mo, V and Fe, zero < x < 0.2, 0.1 < a < 0.95, zero < b < 0.9 (such as 0.05 < b < 0.5), zero < c < 0.6, zero < d < 0.1 , and a + b + c + d = 1.

[0053] Exemplary lithiated nickel cobalt manganese oxides include

[0054] Li(i +x)[N io.33COo.33Mno.33](1 -x)02,

[0055] Li(i +X)[N io.5Coo.2Mno.3](i -x)02, Li(i +x)[N io.6Coo.2Mno.2](i -x)02, Li(i +x)[N io.7Coo.2Mno.i ](i -x)02,

[0056] Li(i+X)[Nio.8Coo.iMno.i](i-x)02, each with x as defined above, and Li[Nio.85COo.i3Aloo2]02.

[0057] In some embodiments, the battery material comprises lithiated nickel-cobalt aluminum oxides of formula Li[NihCo lj]O2+r, wherein h ranges from 0.8 to 0.90, i ranges from 0.1 to 0.3, j ranges from 0.01 to 0.10, and r ranges from zero to 0.4.

[0058] In some embodiments, the battery material comprises nickel, cobalt, manganese, copper, aluminum, iron, phosphorus, or combinations thereof. In some embodiments, the battery material has a weight ratio ranging from 0.01 to 100 of lithium to a total weight of nickel, cobalt, manganese, copper, aluminum, iron, and phosphorus. In some embodiments, wherein the battery material has a weight ratio ranging from 0.01 to 10 of lithium to a total weight of nickel, cobalt, manganese, copper, aluminum, iron, and phosphorus. In some embodiments, wherein the battery material has a weight ratio ranging from 0.01 to 5 of lithium to a total weight of nickel, cobalt, manganese, copper, aluminum, iron, and phosphorus. In some embodiments, wherein the battery material has a weight ratio ranging from 0.01 to 2 of lithium to a total weight of nickel, cobalt, manganese, copper, aluminum, iron, and phosphorus. In some embodiments, wherein the battery material has a weight ratio ranging from 0.01 to 1 of lithium to a total weight of nickel, cobalt, manganese, copper, aluminum, iron, and phosphorus.

[0059] In some embodiments, the battery material comprises LixMO2 wherein x is an integer greater than or equal to one, and M is chosen from metals, transition metals, rare earth metals, and combinations thereof. In some embodiments, a process for recycling lithium ion battery materials comprises mechanically comminuting at least one chosen from a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and combinations thereof to obtain a black mass.

[0060] The present disclosure also provides a process for recycling lithium ion battery materials comprising: mechanically comminuting at least one chosen from a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and combinations thereof to obtain a black mass, leaching the black mass to obtain an aqueous solution comprising lithium, and processing the aqueous solution by electrolysis as described above.

[0061] The present disclosure also provides a device for performing the process of the present disclosure, i.e., an electrolysis cell. The electrolysis cell comprises at least one EOL PFAS membrane. In some embodiments, the electrolysis cell comprises at least two EOL PFAS membranes. In some embodiments, the electrolysis cell comprises two EOL PFAS membranes

[0062] The electrolysis cell comprises a cathode and an anode. In some embodiments, the electrolysis cell may be configured in a monopolar or bipolar configuration. The cathode may be any cathode known for electrolysis of an aqueous solution comprising lithium. The anode may be any anode known for electrolysis of an aqueous solution comprising lithium. In some embodiments, the anode is at least one chosen from a metal electrode, a metal oxide electrode, an electrode coated with a platinum group metal, and an electrode coated a platinum group metal oxide. In some embodiments, the thickness of the coating on the anode ranges from 1 micron to 100 microns. In some embodiments, the anode is titanium. In some embodiments, the anode has a geometry chosen from a mesh, a plate, a wire, a foam, and a felt. In some embodiments, the anode is a sheet, a rod, flat, corrugated, rectangular, unsymmetrical, or combinations thereof. In some embodiments, the anode has iridium oxide coated on a titanium substrate. In some embodiments, the anode comprises an electrically conductive substrate with a surface coating of metal oxide doped with at least one precious metal. In some embodiments, the metal oxide is chosen from titanium, tantalum, niobium, zirconium, and combinations thereof. In some embodiments, the precious metal is chosen from platinum, ruthenium, palladium, iridium, rhodium, osmium, and combinations thereof. In some embodiments, the cathode is at least one chosen from a metal electrode, a metal oxide electrode, an electrode with a platinum group metal, and an electrode coated a platinum group metal oxide. In some embodiments, the thickness of the coating on the cathode ranges from 1 micron to 100 microns. In some embodiments, the cathode is at least one chosen from a nickel electrode and a stainless steel electrode. In some embodiments, the cathode has a geometry chosen from a mesh, a plate, a wire, a foam, and a felt. In some embodiments, a cathode is a sheet, a rod, flat, corrugated, rectangular, unsymmetrical, or combinations thereof. In some embodiments, the cathode is a stainless steel electrode. In some embodiments, the cathode is chosen from a porous metal. In some embodiments, the cathode comprises stainless steel, nickel, cobalt, titanium, steel, lead, platinum, and combinations thereof.

[0063] In some embodiments, spacers are positioned between the cathode and the EOL PFAS membrane, and between the anode and the EOL PFAS membrane in the electrolysis cells. The spacers help to extend the lifetime of the cationexchange membranes. In some embodiments, total thickness of the spacers is in the range of from 0.5 to 3 mm, and thickness of a single spacer is in the range of from 0.3 to 2 mm. In some embodiments, the spacers feature a mesh having openings of 0.5 x 0.5 mm or larger, e.g., 2 x 2 mm. In some embodiments, the mesh is comprised of filaments having a diameter in the range of from 0.5 to 1.5 mm, e.g., 1 mm. In some embodiments, the spacers are made of polyethylene (PE) or polypropylene (PP).

[0064] In some embodiments, the electrolysis cell is a three-compartment membrane electrolysis cell. In other embodiments, the electrolysis cell is a two- compartment membrane electrolysis cell.

[0065] In some embodiments, the electrolysis cell is a bipolar electrolysis cell. For example, the electrolysis cell can be a bipolar three-compartment electrolysis cell.

[0066] In some embodiments, the electrolysis cell is an electrolysis cell in which a cathodic compartment is separated from the central or anodic compartment by a cation-exchange membrane.

[0067] In some embodiments, at least one, at least two, at least 10, at least 100, at least 500 electrolysis cells are stacked one after another in fluid communication. A stack of electrolysis cells has an inlet and an outlet.

[0068] In some embodiments, the electrolysis is carried out using an electrolysis stack comprising three compartment cells equipped with monopolar membranes and bipolar electrodes. Such electrodes are effective for evolving gaseous hydrogen (H2) at the cathodic electrode and gaseous oxygen (O2) at the anodic electrode. Such electrodes are effective for splitting water molecules.

[0069] In an exemplary process, the electrolysis is carried out by introducing an aqueous composition comprising lithium sulfate into a central compartment, an aqueous composition comprising lithium hydroxide into a cathodic compartment, and generating an aqueous composition comprising sulfuric acid in an anodic compartment.

[0070] In another exemplary process, the electrolysis is carried out by introducing an aqueous composition comprising lithium sulfate into the compartments of a two- compartment electrolysis cell, and generating hydrogen and an aqueous composition comprising lithium hydroxide in the cathodic compartment, and generating oxygen and an aqueous composition comprising sulfuric acid and lithium sulfate in the anodic compartment.

[0071] During the electrolysis, the aqueous composition comprising lithium hydroxide can be at least substantially maintained at a concentration of lithium hydroxide of about 30 to about 90 g / L, about 40 to about 90 g / L, about 35 to about 70 g / L, about 40 to about 66 g / L, about 45 to about 65 g / L, about 48 to about 62 g / L or about 50 to about 60 g / L.

[0072] During the electrolysis, the aqueous composition comprising lithium hydroxide can be at least substantially maintained at a concentration of lithium hydroxide of about 1 to about 5 M, about 2 to about 4 M, about 2.5 to about 3.5 M, about 2.7 to about 3.3 M, about 2.9 to about 3.1 M or about 3 M.

[0073] During the electrolysis, the aqueous composition comprising sulfuric acid can be at least substantially maintained at a concentration of sulfuric acid of about 30 to about 100 g / L, about 40 to about 100 g / L, about 40 to about 100 g / L, about 60 to about 90 g / L, about 20 to about 40 g / L, about 20 to about 50 g / L, about 25 to about 35 g / L, or about 28 to about 32 g / L.

[0074] During the electrolysis, the aqueous composition comprising sulfuric acid can be at least substantially maintained at a concentration of sulfuric acid of about 0.1 to about 5 M, about 0.2 to about 3M, about 0.3 to about 2 M, about 0.3 to about 1 .5 M, about 0.4 to about 1 .2 M, about 0.5 to about 1 M, or about 0.75 M.

[0075] During the electrolysis, the aqueous composition comprising lithium sulfate can be at least substantially maintained at a concentration of lithium sulfate of about 5 to about 30 g / L, about 5 to about 25 g / L, about 10 to about 20 g / L, or about 13 to about 17 g / L. During the electrolysis, the aqueous composition comprising lithium sulfate can be at least substantially maintained at a concentration of lithium sulfate of about 0.2 to about 3 M, about 0.4 to about 2.5 M, about 0.5 to about 2 M, or about 0.6 to about 1 .8 M.

[0076] During the electrolysis, the temperature of the aqueous composition comprising lithium sulfate or other lithium compounds can be at least substantially maintained at a value of about 20 to about 80° C., about 20 to about 60° C., about 30 to about 40° C., about 50 to about 60° C., or about 46 to about 54° C.

[0077] During the process, the voltage can be at least substantially maintained at a constant value that is about 3 to about 10 V or about 4 to about 7 V. For example, the cell voltage can be at least substantially maintained at a value of about 1 .0 V to about 8.5 V, about 1 .0 V to about 3.0 V, about 2.0 V to about 3.0 V, about 3.0 V to about 8.5 V, about 6.5 V to about 8 V, about 5.5 V to about 6.5 V or about 6 V.

[0078] The present disclosure also provides the use of end-of-life PFAS membranes in the electrolysis of lithium sulfate solutions.

[0079] In summary, the advantages of the process and the device of the present disclosure include providing an opportunity to re-use end-of-life PFAS membranes in the electrolysis of lithium sulfate solutions, thus avoiding the disposal or incineration of used PFAS membranes. In addition, the operational expenditures of lithium sulfate electrolysis can be significantly reduced when end-of-life PFAS membranes are used in electrochemical cells for lithium sulfate electrolysis. The end-of-life PFAS membranes are already fully hydrated and show less swelling during the ramp-up phase of the electrolysis. The end- of-life PFAS membranes show similar performance as pristine PFAS membranes.

[0080] Detailed description of the drawings Fiqure 1 depicts an exemplary electrolysis cell 100. An aqueous solution comprising lithium 101 may be supplied to the electrolysis cell 100. In some embodiments, the aqueous solution comprising lithium 101 is obtained by a process comprising: mechanically comminuting at least one chosen from a lithium ion battery, lithium ion battery waste, lithium ion battery production scrap, lithium ion cell production scrap, lithium ion cathode active material, and combinations thereof to obtain a black mass, and leaching the black mass to obtain an aqueous solution comprising lithium. In some embodiments, the aqueous solution comprising lithium 101 is obtained by leaching a lithium- containing ore. In some embodiments, the aqueous solution comprising lithium 101 is lithium-containing ground water. In some embodiments, the aqueous solution comprising lithium is obtained by leaching a battery material. In some electrolysis cells, such as the exemplary cell depicted in Fig. 1 , there may be one or more cation-exchange membranes 113. Fig. 1 depicts two such membranes 113 as vertical lines. Positive ions, such as Li+, tend to migrate towards the negatively charged electrode 110 whereas negative ions, such as SO42tend to migrate towards the positively charged electrode 111. During electrolysis, basic hydroxide ions may form near the negative electrode 110 and may increase the local pH. During electrolysis, acidic protons may form near the positive electrode 111 and may decrease the local pH. A lithium-enriched and / or more basic aqueous solution 102 may be obtained near the negative electrode 110. A lithium-depleted and / or more acid aqueous solution 104 may be obtained near the positive electrode 111. An aqueous solution 103 which might be lithium-depleted and / or more acid, lithium-enriched and / or more basic, or have substantially the same lithium concentration and / or pH as the feed solution 101 may also be obtained in the central compartment. Here, enriched, depleted, more basic, and more acidic, each refer to properties of the aqueous solution relative to the supplied aqueous solution comprising lithium 101. In some electrolysis cells, such as the exemplary cell depicted in Fig. 1 , spacers 112 may be present between the electrodes 110, 111 and the cation-exchange membranes 113. The spacers prevent direct contact between the electrodes 110, 111 and the cation-exchange membranes 113. In other embodiments not shown in Fig. 1 , a spacer also is present in-between the cation exchange membranes 113.

[0081] Figure 2 shows electrode temperature vs time plots of long-term test runs of electrolysis cells comprising Nation™ N438 cation-exchange membranes (spheres - N438 without spacers, triangles - N438 with spacers). Thermocouples attached to anode and cathode monitored the electrode temperature during the long-term tests. Cell tests without spacers revealed electrode temperatures (anode as well as cathode) well above 100°C after several hundreds of hours straight testing. After disassembling such cells, we could visually observe changes of the cation exchange membrane. Particular areas of the polymer membrane touching the electrodes had turned brown and these areas appeared hard and brittle. We speculate that the polymer membrane started to undergo degradation at elevated temperature. This is a self-propagating process, which proceeds as less membrane area becomes available for the electrolysis process. That in turn leads to higher resistance and increasing temperatures over time.

[0082] The electrode temperatures remained significantly below 100°C after introducing spacers into the test cells. The observed cell voltage remained very constant when spacers were employed, despite the slightly higher cell voltage due to the increased electrode gap. We assume improved gas transport and improved membrane / electrode wetting with electrolyte when spacers are used. This ultimately results in full utilization of the entire electrode and membrane area in the test cell. The observations were made using a NORSCAND® NS-01 two-chamber test cell (NORAM Electrolysis Systems Inc., Vancouver, British Columbia V6C 1 S4, Canada). A different electrolysis cell might show other performance characteristics.

[0083] The thickness of each spacer increased the distance between the two electrodes. As a result, the observed cell voltage increased by 500 to 600 mV. The average cell voltage was between 5.8 and 5.9 V when large spacers were employed. The cell without spacers exhibited an average cell voltage ranging from 5.3 to 5.4 V.

[0084] Figure 3 shows cell voltage vs time plots of an electrolysis cell using a pristine Nation™ N438 cation-exchange membrane and of an electrolysis cell using an EOL Nation™ N438 cation-exchange membrane. The EOL membrane had a thickness of 405 pm, while the pristine membrane had a thickness of 361 pm. Membrane thickness was measured using a Sony DZ521 gauging stand. In the electrolysis cell with the pristine membrane, the current density was increased stepwise during the initial 200 hours to finally reach a value of 400 mA / cm2As can be seen in the corresponding plot, the voltage increased sharply but immediately decayed after each step. After 500 hours, the cell voltage was around 6 V. During the following hours, cell voltage approached values somewhat below 6 V. This finding compared well with previous results.

[0085] The experiment with the EOL membrane confirmed the cell voltage vs time trend as shown in Figure 3. Cell voltage values between 5.8 and 5.9 V were recorded after more than 800 hours. The electrolysis cell with the EOL membrane was operated with a current density of 400 mA / cm2over the entire test period. During the initial phase of the electrolysis experiments, we observed decreasing cell voltages attributed to ongoing water uptake, wetting and swelling of the ion-exchange membrane. As can be seen from the plots, the EOL membrane reaches stable operation much faster than the pristine membrane and performs in electrolysis as well as the pristine membrane.

[0086] List of reference numerals

[0087] 100 electrolysis cell

[0088] 101 aqueous solution comprising lithium (feed)

[0089] 102 lithium-enriched aqueous solution (catholyte)

[0090] 103 aqueous solution comprising lithium (effluent)

[0091] 104 lithium-depleted aqueous solution (anolyte)

[0092] 110 cathode anode spacer cation-exchange membrane

Claims

Claims1 . A process comprising i) operating a sulfonated cation-exchange membrane comprising perfluoroalkyl and polyfluoroalkyl substances (PFAS) in an industrial electrolysis process other than the electrolysis of lithium- containing brines for a time period in the range of from 7.500 hours to 30.000 hours to obtain an end-of-life PFAS membrane, ii) electrolysis of lithium-containing brines in electrochemical cells comprising at least one cation-exchange membrane, wherein the at least one cation-exchange membrane is the end-of-life PFAS membrane.

2. The process of claim 1 , wherein the industrial electrolysis process is the membrane electrolysis of aqueous sodium chloride.

3. The process of claim 1 , wherein the industrial electrolysis process is the membrane electrolysis of aqueous hydrogen chloride.

4. The process of any one of claims 1 to 3, wherein the end-of-life PFAS membrane is a perfluorosulfonate polymer membrane.

5. The process of claim 4, wherein the perfluorosulfonate polymer membrane comprises a tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octene- sulfonic acid copolymer.

6. The process of any one of claims 1 to 5, wherein the end-of-life PFAS membrane has a thickness in the range of from 380 pm to 420 pm.

7. The process of any one of claims 1 to 6, wherein the thickness of the end- of-life PFAS membrane is larger than the thickness of the membrane before operating in the industrial electrolysis process by a factor in the range of from 1.1 to 1.2.

8. The process of any one of claims 1 to 7, wherein the current density during the electrolysis is in the range of from 0.05 A / cm2to 2.0 A / cm29. The process of any one of claims 1 to 8, wherein the cell voltage during the electrolysis is in the range of from 3 V to 7 V.

10. The process of any one of claims 1 to 9, wherein the temperature in the electrochemical cell(s) during electrolysis is in the range of from 40°C to 60°C.

11. An electrolysis cell (100) for the electrolysis of lithium-containing brines (101 ), the electrolysis cell (100) comprising a cathode (110), an anode (111 ), and at least one sulfonated cation-exchange membrane (113) comprising perfluoroalkyl and polyfluoroalkyl substances (PFAS) having been operated in an industrial electrolysis process other than the electrolysis of lithium-containing brines for a time period in the range of from 7.500 hours to 30.000 hours (end-of-life PFAS cation-exchange membrane) positioned between the cathode (110) and the anode (111 ).

12. The electrolysis cell (100) of claim 12, wherein spacers (112) are positioned between the cathode (110) and the at least one end-of-life PFAS cation-exchange membrane (113), and between the anode (111 ) and the at least one end-of-life PFAS cation-exchange membrane (113).

13. Use of a sulfonated cation-exchange membrane comprising perfluoroalkyl and polyfluoroalkyl substances (PFAS) which has been operated in an industrial electrolysis process other than the electrolysis of lithium- containing brines for a time period in the range of from 7.500 hours to30.000 hours (end-of-life PFAS cation-exchange membrane) in the electrolysis of lithium-containing brines in an electrochemical cell.

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