Gas diffusion electrodes used in membrane electrolytic cells

Abstract

A gas diffusion electrode for use in membrane electrolytic cells is provided. A membrane electrolytic cell for processing salt-containing solutions is also provided. Furthermore, a method for producing base products is provided. In particular, a gas diffusion electrode to be placed within a multi-compartment membrane electrolytic cell used for processing lithium is provided.

Description

Cross-reference to related applications

[0001] This application claims priority and benefits under U.S. Patent Application No. 63 / 521,470, filed on 16 June 2023, and U.S. Patent Application No. 63 / 592,525, filed on 23 October 2023, the entire contents of both applications are incorporated herein by reference. [Technical Field]

[0002] This disclosure generally relates to gas diffusion electrodes (GDEs) used in membrane electrolytic cells, membrane electrolytic cells containing the GDEs for processing salt-containing solutions, and processes for producing base products using the membrane electrolytic cells. In particular, this disclosure relates to GDEs in multi-compartment membrane electrolytic cells used for processing salt-containing solutions. [Background technology]

[0003] The surge in global electric vehicle (EV) sales and the acceleration of the transition to renewable energy are dramatically increasing the demand for high-quality battery-grade lithium (lithium hydroxide and lithium carbonate). By 2035, it is projected that all-electric vehicles will be the most significant market segment in the automotive market.

[0004] Currently, there is a gap between the demand and supply of lithium, with demand exceeding supply. As the EV and renewable energy markets continue to expand, the gap between the demand and supply of high-quality battery-grade lithium (lithium hydroxide and lithium carbonate) is also expected to widen.

[0005] Natural sources of lithium include igneous rocks, springs, seawater and oceanic water, as well as Salar brine. Salar brine is an underground reservoir containing high concentrations of dissolved salts such as lithium, potassium, and sodium, and is generally found beneath the surface of the dry lakebed known as Salar.

[0006] Extraction from salar brine Generally, conventional processes for recovering lithium from brine involve multiple pond evaporation and concentration steps, during which high concentrations of sodium and potassium salts with lower solubility than the desired lithium salt, such as NaCl, KCl, and other salts, are removed by precipitation. Evaporation increases the lithium concentration in the brine. Some magnesium is also removed during this evaporation process in the form of precipitated MgCl2. In the next step, boron, calcium, and magnesium, which are major sources of impurities in the brine, are removed. The removal of B, Ca, and Mg ions is carried out using repeated pH adjustment, solvent extraction, and precipitation steps to ensure maximum ion removal. The brine is further purified by removing trace amounts of monovalent, divalent, and trivalent ions other than lithium by ion exchange. The final major step for producing industrial and high-purity lithium carbonate is the introduction of soda ash (Na2CO3) to convert the dissolved lithium salt into lithium carbonate (Li2CO3).

[0007] Extraction from rock mining Some minerals contain lithium (Li) in their structure. For example, at least four minerals are attracting attention as promising sources of lithium (Li). These include lepidolite (K(Li,Al,Rb)2(Al,Si)4O 10 (F,OH)2), spodumene (LiAl(SiO3)2), petalite (LiAlSi4O 10 These include ), and amblygonite ((Li,Na)AIPO4(F,OH)). Of these, spodumene is usually the most important ore in commercial lithium production.

[0008] Generally, conventional processes for recovering lithium from spodumene involve crushing the mined ore, roasting it, cooling it, further grinding it, and then roasting it again with sulfuric acid in an acid leaching process. Further precipitation and / or ion exchange steps may be performed to remove impurities before adding soda ash to precipitate lithium carbonate as the final product.

[0009] There is a growing need for new recovery processes and related equipment. [Overview of the project]

[0010] This disclosure provides a gas diffusion electrode for use in a membrane electrolytic cell. Furthermore, this disclosure provides a membrane electrolytic cell comprising the gas diffusion electrode and an advantageous structural configuration thereof. The gas diffusion electrode and membrane electrolytic cell of this disclosure can be advantageously used to process a salt-containing solution to produce one or more desired base products.

[0011] In one embodiment, the present disclosure relates to a gas diffusion electrode used in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer. This gas diffusion electrode is referred to herein as GDE-1.

[0012] In one embodiment, the disclosure relates to GDE-1, further comprising an anion exchange membrane disposed on the surface of the catalyst layer, wherein the anion exchange membrane is configured to exchange ions from the catalyst layer to the opposite surface of the anion exchange membrane.

[0013] In one embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-1 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the anode to the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet for introducing a gas containing O2 into contact with the gas diffusion electrode, and at least one outlet from which the products of the salt solution are removed from inside the membrane electrolytic cell.

[0014] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the cathode compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions combine with the positive salt ions to form the base product, and the base product is removed from the cathode compartment.

[0015] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing salt-containing solutions. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-1 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, an anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base storage compartment via the opposite surface of the anion exchange membrane, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0016] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the anion exchange membrane and move into the base accumulation compartment via the surface opposite to the anion exchange membrane, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0017] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-1 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, which receives ions from the catalyst layer of the gas diffusion electrode to the base accumulation compartment via the opposite surface of the first anion exchange membrane. The electrolytic cell comprises: a first anion exchange membrane configured for exchange; a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the second anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0018] In one embodiment, the present disclosure relates to a method for producing a base product. The method includes receiving, in the membrane electrolysis cell described in the immediately preceding paragraph, a salt-containing solution containing positive and negative salt ions and a gas containing O2, and removing the base product from the membrane electrolysis cell. In the implementation of the method, the salt-containing solution is supplied to a salt depletion section, the positive salt ions pass through the cation exchange membrane and move into the base accumulation section through the surface on the opposite side of the cation exchange membrane, the gas containing O2 is reduced at the cathode to generate OH - ions, the OH - ions pass through the first anion exchange membrane and move into the base accumulation section through the surface on the opposite side of the first anion exchange membrane, the OH - ions combine with the positive salt ions in the base accumulation section to generate the base product, and the base product is removed from the base accumulation section.

[0019] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing salt-containing solutions. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-1 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, the first anion exchange membrane configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base accumulation compartment via the opposite surface of the first anion exchange membrane, and the salt depletion compartment and the The membrane electrolytic cell comprises: a first cation exchange membrane interposed between the base accumulation compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the second anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0020] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the surface opposite to the first anion exchange membrane, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0021] In one embodiment, the present disclosure relates to a gas diffusion electrode used in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst coating film including a catalyst layer disposed on the surface of the film. This gas diffusion electrode is referred to herein as GDE-2.

[0022] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-2 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet disposed within the cathode compartment into which a gas containing O2 is introduced so as to contact the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0023] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0024] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment. The electrolytic cell comprises: a cation exchange membrane configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0025] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions move through the catalyst coating exchange membrane into the base accumulation compartment, and the OH -The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0026] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode comprising GDE-2 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; and a first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, which exchanges ions received from the salt depletion compartment. The electrolytic cell comprises: a first cation exchange membrane configured to exchange ions to the base accumulation compartment via the opposite surface of the membrane; an anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0027] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and through the opposite surface of the first cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0028] In one embodiment, the present disclosure relates to a gas diffusion electrode used in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer disposed on the gas diffusion layer, wherein the catalyst layer has a thickness optimized such that liquid reactants diffusing across the catalyst layer are substantially or completely consumed before reaching the gas diffusion layer. This gas diffusion electrode is referred to herein as GDE-3.

[0029] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment which together with the cathode compartment form a single compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-3 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet disposed within the cathode compartment into which a gas containing O2 is introduced so as to contact the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0030] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolytic cell.

[0031] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment which together with the cathode compartment form a single compartment, a salt depletion compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-3 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, wherein ions received from the salt depletion compartment are transferred to the cation exchange membrane. The electrolytic cell comprises a cation exchange membrane configured to exchange ions to the base accumulation compartment via its opposite surface; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via its opposite surface; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0032] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolytic cell.

[0033] In one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment which together with the cathode compartment forms a single compartment, a salt depletion compartment and an acid storage compartment interposed between the cathode compartment and the anode compartment, wherein the salt depletion compartment is interposed between the base storage compartment and the acid storage compartment, and the acid storage compartment is interposed between the salt depletion compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-3 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a first cation exchange membrane interposed between the salt depletion compartment and the base storage compartment, wherein ions received from the salt depletion compartment are transferred to the opposite surface of the cation exchange membrane. The electrolytic cell comprises: a first cation exchange membrane configured to exchange ions to the base accumulation compartment; an anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0034] In one embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and through the opposite surface of the first cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolytic cell.

[0035] In one embodiment, the present disclosure relates to a gas diffusion electrode used in a membrane electrolytic cell. The gas diffusion electrode comprises a first gas diffusion layer for diffusing an oxygen-containing gas, a catalyst layer disposed on the surface of the first gas diffusion layer, a second gas diffusion layer in contact with the surface of the catalyst layer opposite to the first gas diffusion layer, and an ionomer layer disposed on the surface of an anion exchange membrane and in contact with the surface of the second gas diffusion layer opposite to the catalyst layer. This gas diffusion electrode is referred to herein as GDE-4. In one embodiment, the GDE-4 further comprises a microporous layer disposed on the surface of the second gas diffusion layer, the microporous layer in contact with the surface of the catalyst layer opposite to the first gas diffusion layer.

[0036] In one embodiment, the present disclosure relates to a GDE for a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas, and a catalyst layer disposed on the surface of the diffusion layer. In a particular embodiment, the catalyst layer comprises a catalyst and an ionomer in an ionomer:catalyst ratio ranging from 1:1 to 1:20.

[0037] In one embodiment, the present disclosure relates to a GDE for a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas, a microporous layer disposed on the surface of the gas diffusion layer, and a catalyst layer disposed on the surface of the microporous layer. In a particular embodiment, the catalyst layer comprises a catalyst and an ionomer in an ionomer:catalyst ratio ranging from 1:1 to 1:20.

[0038] In one embodiment, the present disclosure relates to a membrane electrolytic cell for producing a base, wherein the following reaction occurs: O2 + 2H2O + 4e - →4OH - The present invention relates to a membrane electrolytic cell comprising a gas diffusion electrode (GDE) configured as an oxygen depolarization cathode to catalyze a gas. In a particular embodiment, the GDE comprises a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer disposed on the surface of the diffusion layer, wherein the catalyst layer contains a catalyst and an ionomer in an ionomer:catalyst ratio ranging from 1:1 to 1:20.

[0039] In one embodiment, the present disclosure relates to a membrane electrolytic cell for producing a base, wherein the following reaction occurs: O2 + 2H2O + 4e - →4OH - The present invention relates to a membrane electrolytic cell comprising a gas diffusion electrode (GDE) configured as an oxygen depolarization cathode to catalyze a gas. In a particular embodiment, the GDE comprises a gas diffusion layer for diffusing an oxygen-containing gas, a microporous layer disposed on the surface of the diffusion layer, and a catalyst layer disposed on the surface of the microporous layer, wherein the catalyst layer contains a catalyst and an ionomer in an ionomer:catalyst ratio ranging from 1:1 to 1:20.

[0040] In one embodiment, the present disclosure relates to a membrane-coated GDE used in the membrane electrolytic cell disclosed herein or any other membrane electrolytic cell, comprising a GDE including a gas diffusion layer (GDL) for diffusing an oxygen-containing gas and a catalyst layer, and an anion exchange membrane (AEM) coated on the GDE.

[0041] In one embodiment, the present disclosure relates to a method for manufacturing a film-coated gas diffusion electrode. The method includes the steps of: preparing a coating mixture by mixing an ionomer in a solvent; applying the coating mixture to a gas diffusion electrode; and curing the mixture to form the film-coated gas diffusion electrode.

[0042] Other aspects and embodiments of this disclosure will become apparent in light of the detailed description set forth herein. [Brief explanation of the drawing]

[0043] Further advantages, variations, and combinations of the Disclosure will become apparent from the following detailed descriptions of various specific embodiments of the Disclosure, which are described in conjunction with the above description and accompanying drawings. However, none of these shall limit the Disclosure. [Figure 1] These are structural diagrams of eight exemplary gas diffusion electrodes (GDE-1) of the present disclosure, comprising at least a catalyst layer (CL) and a gas diffusion layer (GDL) (panel (a)), and in some exemplary embodiments of the GDE-1, further comprising a microporous layer (MPL), a mesh, an anion exchange membrane (AEM), or a combination thereof (panels (b), (c), (d), (e), (f), (g), and (h)). [Figure 2] These are structural diagrams of four exemplary gas diffusion electrodes (GDE-2) of the present disclosure, comprising at least a gas diffusion layer and a catalyst coating (CCM) (panel (a)), and in some exemplary embodiments of the GDE-2, further comprising a microporous layer (MPL), a mesh, or a combination thereof (panels (b), (c), and (d)). [Figure 3] The diagrams show two three-dimensional exemplary gas diffusion electrodes (GDE-3) of the present disclosure, comprising at least a gas diffusion layer (GDL) and a catalyst layer (CL) having a thickness (τ) configured to consume liquid reactants diffusing toward the GDL (panel (a)), and in another exemplary embodiment, further comprising a mesh (panel (b)). [Figure 4]The diagrams show four exemplary gas diffusion electrodes (GDE-4) of the present disclosure, comprising at least a first gas diffusion layer (first GDL), a catalyst layer (CL), an ionomer layer (IL), an anion exchange membrane (AEM), and a second gas diffusion layer (second GDL) disposed between them (panel (a)), and in some exemplary embodiments of the GDE-4, further comprising a microporous layer (MPL), a mesh, or a combination thereof (panels (b), (c), and (d)). [Figure 5] This is a schematic diagram of an exemplary five-compartment membrane electrolytic cell of the present disclosure, showing the supply stream and product stream. [Figure 6] This is a diagram of an exemplary four-compartment membrane electrolytic cell of the present disclosure, showing the supply stream and product stream. [Figure 7] This is a diagram of an exemplary three-compartment membrane electrolytic cell of the present disclosure, showing the supply stream and product stream. [Figure 8] This is a diagram of an exemplary two-compartment membrane electrolytic cell of the present disclosure, showing the supply stream and the product stream. [Figure 9] This is a process flow diagram illustrating the use of one embodiment of a membrane electrolytic cell incorporated into a lithium recovery process from brine. [Figure 10] This is a process flow diagram illustrating the use of one embodiment of a membrane electrolytic cell incorporated into a lithium extraction process from ore. [Figure 11] This is a process flow diagram of one embodiment of a process for on-site production of LiOH, Li2CO3, and HCl from LiCl brine, incorporated into a process for recovering Li from Salar brine by conversion of LiCl → LiOH + HCl. [Figure 12] This is a process flow diagram of one embodiment of a process for on-site production of LiOH, Li2CO3, and HCl from LiCl brine, which is incorporated into a process for recovering Li from Salar brine by the conversion of LiCl to LiOH and HCl. [Figure 13]This is a process flow diagram of one embodiment of on-site production of crystallized LiOH from a mixed brine of LiCl and NaCl, which is incorporated into a process for recovering Li from Salar brine by conversion of LiCl → LiOH + HCl and conversion of NaCl → NaOH + HCl within the same cell. [Figure 14] This is a process flow diagram of one embodiment of on-site generation of LiOH and H2SO4 from Li2SO4, incorporated into an intermediate stream of the lithium recovery process in hard rock mining operations through the conversion of Li2SO4 to LiOH + H2SO4. [Figure 15] This is a process flow diagram of one embodiment for producing LiOH from Li2CO3, which is a closed-loop process in which the generated HCl is recycled and used to dissolve Li2CO3. [Figure 16] This is a process flow diagram of one embodiment of LiOH production, incorporated into a process for recovering Li from lithium brine by selective adsorption of Li using an ion exchange resin via the conversion of LiCl → LiOH + HCl. HCl is used for regenerating the ion exchange resin. [Figure 17] This is a process flow diagram of another embodiment of LiOH production, incorporated into a process for recovering Li from lithium brine by selective adsorption of Li using an ion exchange resin via the conversion of LiCl → LiOH + HCl. HCl is used for regenerating the ion exchange resin. [Figure 18] This is a process flow diagram of one embodiment of alkali (e.g., LiOH) production, which is incorporated into a process for recovering Li from a Li source by selective extraction of Li using solvent extraction (SX) and electrolysis of a lithium salt-containing solution. [Modes for carrying out the invention]

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this disclosure pertains. In the implementation or testing of this disclosure, methods and materials similar to or equivalent to those described herein may be used, but suitable methods and materials are described below.

[0045] This disclosure relates to a gas diffusion electrode (GDE) used in a membrane electrolytic cell, a membrane electrolytic cell containing the GDE for processing a salt-containing solution, and a process for producing a base product using the membrane electrolytic cell.

[0046] In one embodiment, the salt-containing solution includes LiCl, Li2SO4, Li3PO4, LiNO3, LiI, NaCl, Na2SO4, Na3PO4, NaNO3, NaI, KCl, K2SO4, K3PO4, KNO3, or KI, or a combination thereof.

[0047] In one embodiment, the base product includes LiOH, NaOH, or KOH, or a combination thereof.

[0048] This disclosure offers several advantages compared to certain existing technologies. One advantage of this disclosure is the provision of a unique GDE and the use of said GDE in a multi-compartment membrane electrolytic cell that can use ambient, non-dry, humid air as an oxygen source. According to some embodiments, the disclosed GDE is used in or only within the cathode compartment of the membrane electrolytic cell disclosed herein.

[0049] In a further embodiment, the disclosure advantageously enables: improving Li extraction from various sources, including brine sources or lithium ore sources, which may require hydrochloric acid, sodium hydroxide, and / or sulfuric acid; eliminating the need to externally source acid and base materials by utilizing brine already available on-site, whether it is derived from salar brine, a brine solution produced during a lithium ore refining process, or brine produced during a lithium-ion battery recycling process; directly converting lithium-containing salts, such as lithium chloride and lithium sulfate, into higher-value lithium hydroxide and lithium carbonate products; providing membrane electrolytic cells for improving the processing of salt-containing solutions; and / or providing a process for producing lithium hydroxide or lithium carbonate using membrane electrolytic cells.

[0050] In this specification, the terms “oxygen depolarized cathode,” “ODC,” “gas diffusion cathode,” and “GDC” are used interchangeably and / or refer to the same structure used, for example, as a cathode in a membrane electrolytic cell. In embodiments of this disclosure, such a cathode structure may include the GDE of this disclosure.

[0051] In this specification, the terms “membrane electrode assembly” and “MEA” are used interchangeably and refer to an ion exchange membrane placed on a gas diffusion electrode (GDE).

[0052] In this specification, the term “disposed on” means any form in which one substrate or material is permanently or consistently disposed on or in contact with another substrate or material. For example, the expression “disposed on” may be used to refer to any means by which one substrate or material is attached to, sprayed, coated, hot-pressed, Teflon-coated, laminated, placed adjacent to and in contact with, or otherwise disposed on or in contact with the second substrate or material.

[0053] In this specification, the term "porosity" refers to the proportion of voids in a material. In one embodiment, this represents the ratio of the volume of voids or holes in the material to its total volume. For example, if half of the volume of a material is voids or holes, the porosity of that material is 50%.

[0054] Gas diffusion electrode (GDE) In one embodiment, the present disclosure relates to a gas diffusion electrode (GDE) used in a membrane electrolytic cell.

[0055] The gas diffusion electrode comprises a porous catalyst layer placed on a support material. The catalyst layer conducts electrons and catalyzes the electrochemical reaction between the liquid and the gas. Thus, the electrochemical reaction occurs at the so-called three-phase interface where the gas, liquid, and solid (i.e., catalyst) are in contact.

[0056] In one embodiment, the gas contains oxygen and the liquid contains water, resulting in the following cathode reaction. O2 + 2H2O + 4e - →4OH -

[0057] In this case, GDE allows membrane electrolytic cells to operate using air as the oxygen source at the cathode. This could represent a significant economic and safety advancement in the ability to incorporate these cells into processes for producing bases (e.g., alkali metal compounds such as alkali metal hydroxides).

[0058] In yet another embodiment, the gas contains oxygen mixed with carbon dioxide, and the following cathode reaction occurs: O2 + 2H2O + 4e - →4OH - OH - +CO2→HCO3 - HCO3 - +OH - →CO3 2- +H2O

[0059] In this embodiment, alkali metal carbonates and bicarbonates can be electrochemically generated.

[0060] Various embodiments of the GDE relating to this disclosure are described below with reference to “GDE-1,” “GDE-2,” and “GDE-3.” Non-limiting configurations of these GDE embodiments are shown in Figures 1 (GDE-1), 2 (GDE-2), 3 (GDE-3), and 4 (GDE-4).

[0061] As will be understood by those skilled in the art in light of this disclosure, GDE can be prepared by any of the numerous methods known in the art for coating a catalyst layer onto a substrate (e.g., GDL or film). The form of preparation of the catalyst layer influences the choice of method. Examples include solid / powder (e.g., dry powder spraying, decaling), suspension (e.g., doctor blade, screen printing, inkjet printing, scraping), aerosol (e.g., ultrasonic spraying, irradiation spraying, handbrush air spraying), vapor / plasma (e.g., magnetron sputtering, decal sputtering, helican RF sputtering, chemical vapor deposition), and electrode-assisted deposition (e.g., electrode spraying, electrodeposition, electrophoretic deposition). In one embodiment, the catalyst layer is a suspension and can be coated by, for example, doctor blade, screen printing, inkjet printing, or scraping.

[0062] (GDE-1) In one embodiment of this disclosure, a gas diffusion electrode (GDE-1) comprising a gas diffusion layer (GDL) and a catalyst layer (CL) is provided. In one embodiment, the CL is disposed on the surface of the GDL. See, for example, Figure 1(a).

[0063] In another embodiment, the GDL of GDE-1 may be modified by hydrophobic polymer treatment and / or application of a microporous layer (MPL). In one embodiment, the GDE further comprises an MPL disposed on the surface of the GDL, and the CL is disposed on the surface of the MPL opposite to the GDL. See, for example, Figure 1(b).

[0064] In yet another embodiment, the GDE-1 may include a mesh in contact with the surface of the GDL opposite to the CL (see, for example, Figure 1(c)) or the surface of the GDL opposite to the MPL (see, for example, Figure 1(d)). In one embodiment, the mesh is bonded to the GDL by Teflon coating, hot pressing, or lamination.

[0065] In yet another embodiment, GDE-1 includes an anion exchange membrane (AEM) which can help prevent flooding of the GDE by liquid reactants in the electrochemical cell. In one embodiment, the AEM may be placed on the surface of CL and configured to exchange ions from the catalyst layer to the surface opposite the AEM. See, for example, Figures 1(e) to 1(h). The AEM may be held in direct contact with CL by mechanical means, or it may be bonded to CL by Teflon coating, hot pressing, ionomer, or lamination. Alternatively, the AEM may be coated on the GDE. For example, an anion exchange ionomer can be mixed in a solvent to prepare a coating mixture, this coating mixture can be applied to the GDE, and then cured (e.g., by heating) to form an AEM-coated GDE.

[0066] Accordingly, in another embodiment of the present disclosure, a membrane-coated GDE is provided for use in the membrane electrolytic cell disclosed herein or any other membrane electrolytic cell, comprising a GDE including a GDL for diffusing an oxygen-containing gas and a catalyst layer, and an ion exchange membrane coated on the GDE.

[0067] In yet another embodiment of the present disclosure, a method for preparing a film-coated GDE of the present disclosure is provided. The method includes the steps of: mixing an ionomer in a solvent to prepare a coating mixture; applying the coating mixture to a GDE; and curing it to form the film-coated GDE. The ionomer may be any suitable anion-exchange ionomer, such as any of the anion-exchange ionomers disclosed herein, or a mixture thereof, or may include them. In one embodiment, the ionomer is Fumion TM Ionomer TM Ionomer, Sustainion(R) Ionomer, Orion Ionomer, Pention TM Contains an ionomer, or PiperION ionomer.

[0068] The ionomer may be mixed with the solvent by any suitable method, including but not limited to stirring, mixing, rolling, and spraying. The solvent may be appropriately selected based on the ionomer used. In one embodiment, the solvent is an aqueous or oil-based solvent. In one embodiment, the solvent is an alcohol. In one embodiment, the solvent is ethanol, methanol, propanol, isopropanol, butanol, ethylene glycol, glycerol, isobutanol, or any other suitable alcohol.

[0069] The amount of ionomer mixed with the solvent may depend on the type of ionomer used and / or the solvent used. In one embodiment, the ionomer is mixed in the solvent at a concentration of about 0.5% to about 25% by weight, more specifically about 1% to about 20% by weight, and even more specifically about 2% to about 15% by weight. In one embodiment, the ionomer is mixed in the solvent at a concentration of about 1% to about 5% by weight. In one embodiment, the ionomer is mixed in the solvent at a concentration of about 5% to about 10% by weight. In one embodiment, the ionomer is mixed in the solvent at a concentration of about 10% to about 15% by weight. In one embodiment, the ionomer is mixed in the solvent at concentrations of about 1% by weight, about 2% by weight, about 3% by weight, about 4% by weight, about 5% by weight, about 6% by weight, about 7% by weight, about 8% by weight, about 9% by weight, about 10% by weight, about 11% by weight, about 12% by weight, about 13% by weight, about 14% by weight, about 15% by weight, about 16% by weight, about 17% by weight, about 18% by weight, about 19% by weight, about 20% by weight, about 21% by weight, about 22% by weight, about 23% by weight, about 24% by weight, or about 25% by weight.

[0070] In one embodiment, the step of applying the coating mixture to the GDE is performed in an amount sufficient to impart a coating thickness of approximately 10 μm to approximately 250 μm, more specifically approximately 10 μm to approximately 100 μm, and even more specifically approximately 20 μm to approximately 100 μm. In one embodiment, the thickness of the coating mixture is approximately 10 μm to approximately 75 μm. In one embodiment, the thickness of the coating mixture is approximately 10 μm to approximately 50 μm. In one embodiment, the thickness of the coating mixture is approximately 25 μm to approximately 50 μm. In one embodiment, the thickness of the coating mixture is approximately 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm. These may be the thickness during application or the thickness after curing. As can be seen, it may be necessary to apply a slightly thicker coating mixture to obtain the desired thickness after curing.

[0071] The curing process may be carried out by any suitable means, including but not limited to heating, ultraviolet (UV) irradiation, infrared irradiation, etc. In one embodiment, the curing is carried out by heating. Without limitation, the heating may be heating in an oven or other fully or partially enclosed apparatus, heating by a dryer, blower or other apparatus, contact with a heated surface, or any other suitable heating means. In one embodiment, the curing by heating is carried out at a temperature of about 25°C to about 200°C, more specifically about 40°C to about 150°C, and even more specifically about 50°C to about 140°C. In one embodiment, the curing by heating is carried out at a temperature of approximately 50°C, approximately 55°C, approximately 60°C, approximately 65°C, approximately 70°C, approximately 75°C, approximately 80°C, approximately 85°C, approximately 90°C, approximately 95°C, approximately 100°C, approximately 105°C, approximately 110°C, approximately 115°C, approximately 120°C, approximately 125°C, approximately 130°C, approximately 135°C, approximately 140°C, approximately 145°C, or approximately 150°C.

[0072] (GDE-2) In another embodiment of this disclosure, a gas diffusion electrode (GDE-2) is provided, comprising a gas diffusion layer (GDL) and a catalyst coating film (CCM). In one embodiment, the CL is arranged on the surface of the film to form the CCM. See, for example, Figure 2(a).

[0073] In one embodiment, the CCM refers to an anion exchange membrane coated with CL on one surface. The CCM can improve ion transport through the contact interface between the CL and the membrane. In one embodiment, the GDL is in contact with the CL of the CCM.

[0074] In another embodiment, the GDL of GDE-2 may be modified by hydrophobic polymer treatment and / or application of a microporous layer (MPL). In one embodiment, the GDE further comprises an MPL disposed on the surface of the GDL, the MPL being in contact with the CL of the CCM. See, for example, Figure 2(b).

[0075] In yet another embodiment, the GDE-2 may include a mesh in contact with the surface of the GDL opposite to the CL (see, for example, Figure 2(c)) or the surface of the GDL opposite to the MPL (see, for example, Figure 2(d)). In one embodiment, the mesh is bonded to the GDL by Teflon coating, hot pressing, or lamination.

[0076] (GDE-3) In another embodiment of the present disclosure, a gas diffusion electrode (GDE-3) is provided, comprising a gas diffusion layer (GDL) and a catalyst layer (CL) disposed on the GDL, wherein the catalyst layer has a thickness (τ) optimized such that liquid reactants diffusing across the CL are substantially or completely consumed before reaching the GDL. See, for example, Figure 3(a).

[0077] As the liquid reactant diffuses across the CL of the GDE-3, it is consumed by the electrochemical reaction. As a result, a concentration gradient of the reactants is formed along the depth of the CL. In one embodiment, the final concentration of the liquid reactant may be zero or near zero at the interface between the CL and the GDL. "Near zero" means that the water content at the interface between the CL and the GDL is insufficient to adversely affect the electrochemical reaction of the GDE. In one embodiment, the water content on the CL surface at the interface between the CL and the GDL is less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% relative to the liquid reactant. By controlling the thickness of the CL, and optionally the hydrophobicity and / or porosity of the CL, the concentration gradient can be controlled to ensure more complete utilization of the reactants. Sufficient reaction of the liquid reactant in the CL may eliminate the need to use an ion exchange membrane with the GDE-3 in the electrochemical cell.

[0078] In one embodiment, GDE-3 may include a mesh that contacts the surface of the GDL opposite to the CL (see, for example, Figure 3(b)). In one embodiment, the mesh is bonded to the GDL by Teflon coating, hot pressing, or lamination.

[0079] (GDE-4) In one embodiment of the present disclosure, a gas diffusion electrode (GDE-4) is provided, comprising a first gas diffusion layer (first GDL), a catalyst layer (CL), a second gas diffusion layer (second GDL), an ionomer layer (IL), and an anion exchange membrane (AEM). In one embodiment, the CL is located on the surface of the first GDL. In another embodiment, the surface of the second GDL is in contact with the CL. In yet another embodiment, the IL is bonded to the AEM. In yet another embodiment, the IL is in contact with the surface of the second GDL opposite to the CL. See, for example, Figure 4(a).

[0080] In another embodiment, the second GDL of GDE-4 may be modified by hydrophobic polymer treatment and / or application of a microporous layer (MPL). In one embodiment, the GDE further comprises an MPL disposed on the surface of the second GDL. In this embodiment, the MPL is in contact with the CL. See, for example, Figure 4(b).

[0081] In yet another embodiment, GDE-4 may include a mesh that contacts the surface of the first GDL opposite to the CL (see, for example, Figure 4(c) or Figure 4(d)).

[0082] As described above, GDE-4 includes a first GDL and a second GDL. In one embodiment, the first GDL and the second GDL in GDE-4 are identical. In another embodiment, the first GDL and the second GDL in GDE-4 are different from each other. For example, the first GDL and the second GDL may have the same or different pore structure, the same or different porosity, the same or different thickness, be formed from the same or different material (e.g., any of (1a) to (5f) described herein), be modified or not by hydrophobic polymer treatment and / or application of a microporous layer, or any combination thereof may be independently selected for each of the first GDL and the second GDL.

[0083] The surface of any GDE described herein, or the surface of an anion exchange film (AEM) placed on any GDE described herein, may have an embossed and / or debossed pattern to effectively increase the active surface area. The pattern may be formed by any known method, including but not limited to engraving, molding, stamping, etc. The pattern may be any suitable pattern that increases the surface area of ​​the substrate or material.

[0084] The following sections will provide a more detailed explanation of the various features of the GDE mentioned above, such as GDL, MPL, and CL.

[0085] (Gas Diffusion Layer (GDL)) A GDL is a porous structure that can function as a gas diffuser and / or current collector. In one embodiment, the GDL may have a relatively uniform pore size throughout its thickness. In another embodiment, the GDL may have a random pore size throughout its thickness. In yet another embodiment, the GDL may have a pore size gradient throughout its thickness. For example, the GDL may have a gradient from large pore size to small pore size in the gas flow direction throughout its thickness. Alternatively, the GDL may have a gradient from small pore size to large pore size in the gas flow direction throughout its thickness.

[0086] The thickness of GDL is 50μm~1000μm, 50μm~950μm, 50μm~900μm, 50μm~850μm, 50μm~800μm, 50μm~750μm, 50μm~700μm, 50μm~650μm, 50μm~600μm, 50μm~550μm, 50μm~500μm, 50μm~450μm, 50μm~400μm, 50μm~350μm, 50μm~300μm, 50μm~250μm, 50μm~200μm, 50μm~150μm, 50μm~100μm, 100 μm~1000μm, 150μm~1000μm, 200μm~1000μm, 250μm~1000μm, 300μm~1000μm, 350μm~1000 μm, 400μm~1000μm, 450μm~1000μm, 500μm~1000μm, 550μm~1000μm, 600μm~1000μm, 650 μm~1000μm, 700μm~1000μm, 750μm~1000μm, 800μm~1000μm, 850μm~1000μm, 900μm~1000 μm, 950μm~1000μm, 100μm~950μm, 150μm~900μm, 200μm~850μm, 250μm~800μm, 300μm~750μm, 350μm~700μm, 400μm~650μm, 450μm~600μm, 500μm~550μm, 200μm m~400μm、210μm~390μm、220μm~380μm、230μm~370μm、240μm~360μm、250μm~35 0μm、260μm~340μm、270μm~330μm、280μm~320μm、or 290μm~310μm can be range.

[0087] The average diameter of GDL can be 1μm~100μm、1μm~90μm、1μm~80μm、1μm~70μm、1μm~60μm、1μm~50μm、1μm~40μm、1μm~30μm、1μm~20μm、or 1μm~10μm。

[0088] The porosity of GDL may be in the range of 50%~95%, 50%~90%, 50%~85%, 50%~80%, 50%~75%, 50%~70%, 50%~65%, 50%~60%, 50%~55%, 55%~95%, 60%~95%, 65%~95%, 70%~95%, 75%~95%, 80%~95%, 85%~95%, 90%~95%, 55%~90%, 60%~85%, 65%~80%, or 70%~75%.

[0089] GDL may include carbon fiber paper, carbon cloth, carbon felt, carbon foam, metal mesh, metal foam, or any combination thereof. GDL may be modified by hydrophobic polymer treatment and / or application of a microporous layer (MPL).

[0090] Non-specific examples of carbon fiber paper include the following: (1a) Toray TGP-H carbon fiber paper (e.g., TGP-H-030, TGP-H-060, TGP-H-090, TGP-H-120) (1b) AvCarb(R) carbon fiber paper (e.g., MGL190, MGL280, MGL370, MGL190T, MGL280T, MGL370T, EP40, EP40T, EP55, EP55T, GDS1120, GDS2120, GDS22100, GDS2230, GDS2240, GDS3215, GDS3250, GDS3260, GDS5130, MB30, P50, P50T, P75, P75T) (1c)Spectracarb TM Carbon fiber paper (e.g., 2050A-0850, 2050A-1050, 2050A-1535, 2050A-1550, 2050A-1550 Treated) (1d) Freudenberg carbon fiber paper (e.g., H14, H14C7, H14C9, H14C10, H14Cx653, H15, H15C13, H15C14, H23, H23C2, H23C3, H23C5, H23C6, H23C7, H23C8, H23C9, H23Cx653, H23I2) (1e) Sigracet(R) carbon fiber paper (e.g., 22 BB, 25 BA, 25 BC, 28 AA, 28 BC, 29 AA, 29 BC, 36 AA, 36 BB, 39 AA, 39 BB) (1f) CeTech carbon fiber paper (e.g., GDS180S, GDS210, GDS230, GDS250, GDS310, GDL240, GDL280, GDL340, GDS090S, GDS180HT, GDL120, GDL210SHT) (1g) JNT Carbon Fiber Paper Series (Examples: JNT15B, JNT17B, JNT18B, JNT20, JNT21, JNT30) (1h) LINQCELL Carbon Fiber Paper (e.g., GDP180, GDP210, GDP210-MP, GDP210MPS, GDP240, GDP340) (1i) Mitsubishi Chemical PYROFIL TM GDL

[0091] Non-specific examples of carbon cloth include the following: (2a) AvCarb(R) carbon cloth (e.g., 1071, 1698, 1209, 1185, 1186, 7497, T1819, T1820, T1824) (2b) E-TEK carbon cloth (e.g., CC4, CC4 Wet Proofed, CC6, CC6 Wet Proofed, ELAT plain cloth, ELAT LT1400, ELAT LT2400W) (2c) CeTech carbon cloth (e.g., W0S1009, W0S1011, W1S1011) (2d)Zoltek TM Panex carbon cloth (e.g., PW03, PW06, SW08) (2e) LINQCELL carbon cloth (e.g., CF350, CF400-MP) (2f) SAATI SCCG carbon cloth (e.g., 5N)

[0092] Non-specific examples of carbon felt include the following: (3a) AvCarb(R) Felt (Examples: C100, C200, C280, G100, G200, G300A, G475A, G600A) (3b) CeTech felt (e.g., CF120, GF20, GF100) (3c) JNT Felt (e.g., GF051BH, GF061AH)

[0093] Non-limiting examples of metal forms include the following: (4a) Nickel foam (4b) Copper foam (4c) Titanium Foam (4d) Silver Form (4e) Stainless steel foam (4f) Iron nickel foam (4g) Nickel copper foam (4h) Cobalt Foam

[0094] Non-limiting examples of metal meshes include the following: (5a) Copper metal mesh (5b) Nickel metal mesh (5c) Titanium metal mesh (5d) Silver Metal Mesh (5e) Stainless steel metal mesh (5f) Molybdenum metal mesh

[0095] Those skilled in the art will be able to fully understand, by considering this disclosure, other suitable materials and compositions of GDL, including those further described herein.

[0096] (Hydrophobic polymer treatment of GDL) In one embodiment, GDL may be modified with a hydrophobic polymer. Modification of GDL by hydrophobic polymer treatment involves applying a hydrophobic additive to GDL to control its wettability.

[0097] Non-limiting examples of such hydrophobic additives include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene propylene fluoride (FEP), perfluoropolyether (PFPE), and polydimethylsiloxane (PDMS). GDL may be modified with any one or any combination of these hydrophobic additives.

[0098] GDL may not contain hydrophobic additives, or may contain hydrophobic additives in amounts of 0.01% to 50% by weight, 0.01% to 45% by weight, 0.01% to 40% by weight, 0.01% to 35% by weight, 0.01% to 30% by weight, 0.01% to 25% by weight, or 0.01% by weight. It may contain in the range of % to 20% by weight, 0.01% to 15% by weight, 0.01% to 10% by weight, 0.01% to 5% by weight, 5% to 50% by weight, 10% to 50% by weight, 15% to 50% by weight, 20% to 50% by weight, 25% to 50% by weight, 30% to 50% by weight, 35% to 50% by weight, 40% to 50% by weight, 45% to 50% by weight, 5% to 45% by weight, 10% to 40% by weight, 15% to 35% by weight, 20% to 30% by weight, 25% to 45% by weight, or 30% to 40% by weight.

[0099] (Microporous layer (MPL)) The MPL is placed on the GDL and can assist with electrical conductivity and / or water management.

[0100] The MPL comprises particulate material coated onto a flat surface of the GDL. Any suitable particulate material can be used. In one embodiment, the particulate material may be a mixture of carbon black and a hydrophobic polymer such as polytetrafluoroethylene (PTFE).

[0101] MPL may contain carbon black in the range of 50% to 95% by weight, 55% to 95% by weight, 60% to 95% by weight, 65% to 95% by weight, 70% to 95% by weight, 75% to 95% by weight, 80% to 95% by weight, 85% to 95% by weight, 90% to 95% by weight, 60% to 90% by weight, 60% to 85% by weight, 60% to 80% by weight, 60% to 75% by weight, 60% to 70% by weight, 60% to 65% by weight, 65% to 90% by weight, 70% to 85% by weight, or 75% to 80% by weight.

[0102] MPL may contain hydrophobic polymers in the ranges of 5% to 50% by weight, 5% to 45% by weight, 5% to 40% by weight, 5% to 35% by weight, 5% to 30% by weight, 5% to 25% by weight, 5% to 20% by weight, 5% to 15% by weight, 5% to 10% by weight, 10% to 40% by weight, 15% to 40% by weight, 20% to 40% by weight, 25% to 40% by weight, 30% to 40% by weight, 35% to 40% by weight, 10% to 35% by weight, 15% to 30% by weight, or 20% to 25% by weight.

[0103] The thickness of the MPL may be in the range of 10μm~100μm, 10μm~90μm, 10μm~80μm, 10μm~70μm, 10μm~60μm, 10μm~50μm, 10μm~40μm, 10μm~30μm, 10μm~20μm, 20μm~100μm, 30μm~100μm, 40μm~100μm, 50μm~100μm, 60μm~100μm, 70μm~100μm, 80μm~100μm, 90μm~100μm, 20μm~90μm, 30μm~80μm, 40μm~70μm, or 50μm~60μm.

[0104] The average pore size of MPL may also be in the range of 0μm~10μm, 0μm~9μm, 0μm~8μm, 0μm~7μm, 0μm~6μm, 0μm~5μm, 0μm~4μm, 0μm~3μm, 0μm~2μm, 0μm~1μm, 0μm~0.9μm, 0μm~0.8μm, 0μm~0.7μm, 0μm~0.6μm, 0μm~0.5μm, 0μm~0.4μm, 0μm~0.3μm, 0μm~0.2μm, or 0μm~0.1μm.

[0105] The porosity of MPL may be in the range of 30%~75%, 30%~70%, 30%~65%, 30%~60%, 30%~55%, 30%~50%, 30%~55%, 30%~50%, 30%~45%, 30%~40%, 30%~35%, 35%~75%, 40%~75%, 45%~75%, 50%~75%, 55%~75%, 60%~75%, 65%~75%, or 70%~75%.

[0106] (Catalyst layer (CL)) The catalyst layer contains a catalyst and may optionally contain an ionomer and / or a binder. In one embodiment, the catalyst layer may contain a catalyst and an ionomer. In another embodiment, the catalyst layer may contain a catalyst and a binder. In yet another embodiment, the catalyst layer may contain a catalyst, an ionomer, and a binder. In yet another embodiment, the GDE has only a single catalyst layer. In yet another embodiment, the GDE may contain multiple catalyst layers.

[0107] The catalyst layer may be hydrophilic or hydrophobic depending on the desired operation of the CL. In one embodiment, when the GDE contains two CLs, the first CL is hydrophilic and the second CL is hydrophobic. In other embodiments, both CLs may be hydrophobic or hydrophilic.

[0108] The thickness of the catalyst layer may be in the range of 1 μm to 100 μm, 1 μm to 95 μm, 1 μm to 90 μm, 1 μm to 85 μm, 1 μm to 80 μm, 1 μm to 75 μm, 1 μm to 70 μm, 1 μm to 65 μm, 1 μm to 60 μm, 1 μm to 55 μm, 1 μm to 50 μm, 1 μm to 45 μm, 1 μm to 40 μm, 1 μm to 35 μm, 1 μm to 30 μm, 1 μm to 25 μm, 1 μm to 20 μm, 1 μm to 15 μm, 1 μm to 10 μm, 1 μm to 9 μm, 1 μm to 8 μm, 1 μm to 7 μm, 1 μm to 6 μm, 1 μm to 5 μm, 1 μm to 4 μm, 1 μm to 3 μm, or 1 μm to 2 μm.

[0109] The porosity of the catalyst layer may be in the range of 30%~75%, 30%~70%, 30%~65%, 30%~60%, 30%~55%, 30%~50%, 30%~55%, 30%~50%, 30%~45%, 30%~40%, 30%~35%, 35%~75%, 40%~75%, 45%~75%, 50%~75%, 55%~75%, 60%~75%, 65%~75%, or 70%~75%.

[0110] The ratio of ionomer to catalyst (ionomer:catalyst) is 1:1~1:20, 1:1~1:19, 1:1~1:18, 1:1~1:17, 1:1~1:16, 1:1~1:15, 1:1~1:14, 1:1~1:13, 1:1~1:12, 1:1~1:11, 1:1~1:10, 1:1~1:9, 1:1~1:8, 1:1~1:7, 1:1~1:6, 1:1~1:5, 1:1~1:4, 1:1~1:3, 1:1~1:2, 1:2~1:20, 1:3~1:20, 1:4~1:20, 1:5~1:20, 1:6~ The time range may be 1:20, 1:7-1:20, 1:8-1:20, 1:9-1:20, 1:10-1:20, 1:11-1:20, 1:12-1:20, 1:13-1:20, 1:14-1:20, 1:15-1:20, 1:16-1:20, 1:17-1:20, 1:18-1:20, 1:19-1:20, 1:2-1:19, 1:3-1:18, 1:4-1:17, 1:5-1:16, 1:6-1:15, 1:7-1:14, 1:8-1:13, 1:9-1:12, or 1:10-1:11.

[0111] (catalyst) The catalyst may include (6) a metal, (7) a nonmetal, or a combination thereof.

[0112] The metal may be (6a) a transition metal, (6b) a post-transition metal, (6c) a metalloid, or a combination thereof, or an alloy thereof.

[0113] Catalysts containing transition metals may include: (6a-a) scandium (Sc), (6a-b) titanium (Ti), (6a-c) vanadium (V), (6a-d) chromium (Cr), (6a-e) manganese (Mn), (6a-f) iron (Fe), (6a-g) cobalt (Co), (6a-h) nickel (Ni), (6a-i) copper (Cu), (6a-j) zinc (Zn), (6a-k) yttrium (Y), (6a-l) zirconium (Z) (6a-m) molybdenum (Mo), (6a-n) ruthenium (Ru), (6a-o) rhodium (Rh), (6a-p) palladium (Pd), (6a-q) silver (Ag), (6a-r) cadmium (Cd), (6a-s) hafnium (Hf), (6a-t) tungsten (W), (6a-u) iridium (Ir), (6a-v) platinum (Pt), (6a-w) gold (Au), or combinations thereof or alloys thereof. In certain embodiments, the catalyst is platinum (6a-v), silver (6a-q), nickel (6a-h), or any combination thereof. In one embodiment, the catalyst is an alloy of (6a-x) platinum and nickel (PtNi). In one embodiment, the alloy has a weight ratio of platinum to nickel of about 5:1 to about 1:5, more specifically about 5:1 to 1:2, and even more specifically about 3:1 to about 1:1. In one embodiment, the alloy has a weight ratio of platinum to nickel of about 5:1, 4.5:1, 4:1, 3.5:1, 3:1, 2.5:1, 2:1, 1.5:1, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, or 1:5.

[0114] Catalysts containing post-transition metals may include: (6b-a) aluminum (Al), (6b-b) gallium (Ga), (6b-c) indium (In), (6b-d) tin (Sn), (6b-e) thallium (Tl), (6b-f) lead (Pb), (6b-g) bismuth (Bi), or combinations thereof, or alloys thereof.

[0115] Metalloid catalysts may include: (6c-a) silicon (Si), (6c-b) germanium (Ge), (6c-c) antimony (Sb), (6c-d) tellurium (Te), or combinations thereof.

[0116] Catalysts containing nonmetals may include: (7a) carbon, (7b) conductive polymers, or a combination thereof.

[0117] Carbon refers to a material whose main component is carbon atoms. For example, carbon may be carbon fibers, graphite, carbon nanomaterials, or a combination thereof. Carbon nanomaterials may include carbon nanotubes, graphene, carbon nanoplates, or fullerenes. Furthermore, the material may optionally be doped with nonmetallic elements (e.g., B, N, P, O, or S).

[0118] The amount of catalyst supported on the GDL is 0.1 to 10 mg / cm³. 22 , 0.1~9.0 mg·cm 22 , 0.1~8.0 mg·cm 22 , 0.1~7.0 mg·cm 22 , 0.1~6.0 mg·cm 22 , 0.1~5.0 mg·cm 22 , 0.1~4.0 mg·cm 22 , 0.1~3.9 mg·cm 22 , 0.1~3.8 mg·cm 22 , 0.1~3.7 mg·cm 22 , 0.1~3.6 mg·cm 22 , 0.1~3.5 mg·cm 22 , 0.1~3.4 mg·cm 22 , 0.1~3.3 mg·cm 22 , 0.1~3.2 mg·cm22 , 0.1 - 3.1 mg·cm 22 , 0.1 - 3.0 mg·cm 22 , 0.1 - 2.9 mg·cm 22 , 0.1 - 2.8 mg cm 22 , 0.1 - 2.7 mg·cm 22 , 0.1 - 2.6 mg·cm 22 , 0.1 - 2.5 mg·cm 22 , 0.1 - 2.4 mg·cm 22 , 0.1 - 2.3 mg·cm 22 , 0.1 - 2.2 mg·cm 22 , 0.1 - 2.1 mg·cm 22 , 0.1 - 2.0 mg·cm 22 , 0.1 - 1.9 mg·cm 22 , 0.1 - 1.8 mg·cm 22 , 0.1 - 1.7 mg·cm 22 , 0.1 - 1.6 mg·cm 22 , 0.1 - 1.5 mg·cm 22 , 0.1 - 1.4 mg·cm 22 , 0.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​In one embodiment, the ionomer includes an anion exchange ionomer. The anion exchange ionomer includes an ionomer in which the ionic group is preferably a cationic group and promotes the conduction of anions through the electrostatic interaction between the cationic group and anions.

[0121] Non-limiting examples of anion exchange ionomers (AEIs) include (8a) Fumion TM FAA-3 AEI, (8b) Ionomr TM AEI (e.g., AF1, AF2, AF, AP1, AP3), (8c) Sustainion(R) AEI (e.g., XA-9, XB-7, XC-1, XC-2), (8d) Orion AEI (e.g., TM1, AM, CMX), (8e) Pention TM AEI (e.g., D18, D35, D72), and (8f) PiperION AEI.

[0122] In one embodiment, the ionomer includes a cation exchange ionomer. The cation exchange ionomer includes an ionomer in which the ionic group is preferably an anionic group and promotes the conduction of cations through the electrostatic interaction between the anionic group and cations.

[0123] Non-limiting examples of cation exchange ionomers (CEIs) include Aquivion(R) CEI (e.g., D72-25BS, D79-25BS, D83-24B, D98-25BS), FORBLUE TM i-SERIES CEI (e.g., IC100, IC154), Fumion TM CEI (e.g., E-600, FSLA-102, FSLA-725), Ionomr TM CEI (e.g., PP1), and Nafion TM CEI (e.g., D520CS, D521CS, D2020CS, D2021CS).

[0124] CL may contain ionomers in the following ranges: 5% to 45% by weight, 5% to 40% by weight, 5% to 35% by weight, 5% to 30% by weight, 5% to 25% by weight, 5% to 20% by weight, 5% to 15% by weight, 5% to 10% by weight, 10% to 45% by weight, 15% to 45% by weight, 20% to 45% by weight, 25% to 45% by weight, 30% to 45% by weight, 35% to 45% by weight, 40% to 45% by weight, 10% to 40% by weight, 15% to 35% by weight, or 20% to 30% by weight.

[0125] (binder) In one embodiment, CL includes a binder. The binder may be, for example, a hydrophilic or hydrophobic polymer. A non-limiting example of the binder is (9a)PTFE.

[0126] CL may not contain a binder, or if it does, the binder may be included in amounts ranging from 0.01% to 40% by weight, 0.01% to 35% by weight, 0.01% to 30% by weight, 0.01% to 25% by weight, 0.01% to 20% by weight, 0.01% to 15% by weight, 0.01% to 10% by weight, 0.01% to 5% by weight, 5% to 40% by weight, 10% to 40% by weight, 15% to 40% by weight, 20% to 40% by weight, 25% to 40% by weight, 30% to 40% by weight, 35% to 40% by weight, 5% to 35% by weight, 10% to 30% by weight, or 15% to 25% by weight.

[0127] The various specific embodiments of the gas diffusion electrodes (GDEs) relating to this disclosure include GDEs described herein as GDE-1, GDE-2, GDE-3, or GDE-4, each having components defined in the following lines, where each item is a group number as defined above: [Table 1-1] [Table 1-2] Table 1-3 Table 1-4 Table 1-5 Table 1-6 Table 1-7 Table 1-8 Table 1-9 Table 1-10 Table 1-11 Table 1-12 Table 1-13 Table 1-14 Table 1-15 Table 1-16 Table 1-17 Table 1-18 Table 1-19

Table 1-20

Table 1-21

Table 1-22

Table 1-23

Table 1-24

[0128] As additional specific embodiments of the GDE according to the present disclosure, GDE embodiments 1a to 896a are included, which have the components defined in GDE embodiments 1 to 896 and do not contain a binder.

[0129] Various additional embodiments of the GDE according to the present disclosure will be understood by those skilled in the art. For example, with respect to the GDE of type GDE-1 described herein, any of embodiments 1 to 896 and 1a to 896a for these GDEs may further include the anion exchange membrane (AEM) described herein, such as those shown in FIGS. 1(e) to (h). Further, with respect to the GDEs of type GDE-1, GDE-2, and GDE-4 described herein, any of embodiments 1 to 896 and 1a to 896a for these GDEs may further include the microporous layer (MPL) described herein, such as those shown in FIGS. 1(b), (d), (f), and (h), FIGS. 2(b) and (d), and FIGS. 4(b) and (d). Further, with respect to the GDEs of type GDE-1, GDE-2, GDE-3, and GDE-4 described herein, any of embodiments 1 to 896 and 1a to 896a for these GDEs may further include the mesh described herein, such as those shown in FIGS. 1(c) to (h), FIGS. 2(c) to (d), FIG. 3(b), and FIGS. 4(c) and (d).

[0130] As described herein, GDE-4 includes a first GDL and a second GDL, which may be the same or different. For GDE-4, in any of Embodiments 1 to 896 or 1a to 896a, at least one of the first GDL and the second GDL is the GDL defined in Embodiment 1 to 896 or 1a to 896a. In one embodiment, the first GDL and the second GDL are the same, and both GDLs included in GDE-4 are the GDLs defined in Embodiment 1 to 896 or 1a to 896a. In another embodiment, the first GDL and the second GDL are different from each other, and only one of the GDLs is the GDL defined in Embodiment 1 to 896 or 1a to 896a. In an embodiment where the GDLs in GDE-4 are different, the first GDL is the GDL defined in Embodiment 1 to 896 or 1a to 896a. Also, in another embodiment where the GDLs in GDE-4 are different, the second GDL is the GDL defined in Embodiment 1 to 896 or 1a to 896a.

[0131] (Anion Exchange Membrane (AEM)) In one embodiment, GDE-1, GDE-2 or GDE-4 according to the present disclosure may include an anion exchange membrane (AEM). Embodiments of AEM are described elsewhere in this specification, and the disclosure thereof is equally applicable to AEM which is a component of GDE.

[0132] In one embodiment, the AEM of GDE comprises a polymer having at least one positively charged cationic group bonded to at least a portion of the polymer backbone. In one embodiment, the polymer comprises polyalkylene, polyfluorene, poly(arylene ether), polysulfone, poly(arylene ethersulfone), polyetherketone, polyetherimide, poly(etheroxadiazole), poly(phenylene oxide), poly(vinylbenzyl), polyphenylene, perfluoroelastomers, polybenzimidazole, polystyrene, or polyphosphazene. In one embodiment, the positively charged cationic group is a primary, secondary, tertiary, or quaternary ammonium, a heterocyclic cation, guanidinium, phosphonium, sulfonium, or a metal cation.

[0133] In one embodiment, the AEM of the GDE is Fumasep TM Neosepta TM Orion TM Xergy Xion Pension TM PiperION TM Ralex TM Sustainment TM , or Ionomr TM It is an anion exchange membrane.

[0134] (Membrane electrolytic cell) In one embodiment, this disclosure relates to a membrane electrolytic cell comprising any of the GDEs described herein. One or more ion exchange membranes are stacked in a specific order depending on the components of the brine stream to be processed and the desired product. These membranes are designed to allow permeability of ionic species having a specific charge. Cation exchange membranes move cation species, while anion exchange membranes allow only anions to pass through the membrane structure. Ion movement is made possible by applying an external voltage using cathode and anode electrodes. Under the applied voltage, anions move toward the positively charged anode and cations move toward the negatively charged cathode. By appropriately arranging the membranes, desired chemical substances such as acids, bases, and salts can be generated.

[0135] In another embodiment of this disclosure, a method for producing a base product (e.g., an alkali metal compound) as described herein includes using a membrane electrolytic cell together with a GDE as described herein.

[0136] Various different types of multi-compartment membrane electrolytic cells, such as those described herein, can be used.

[0137] (5-compartment membrane electrolytic cell) In one embodiment, the membrane electrolytic cell includes five compartments as shown in Figure 5. The membrane electrolytic cell includes a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment. The base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment.

[0138] The anode is housed within the anode compartment.

[0139] The cathode, which includes a gas diffusion electrode (GDE), is housed within the cathode compartment as follows: If the GDE is GDE-1 as described herein, the CL of the GDE shown in Figures 1(a) to (d) is in direct contact with the first AEM shown in Figure 5. In contrast, the AEM of the GDE shown in Figures 1(e) to (h) is the first AEM shown in Figure 5. The first AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the first AEM. The base accumulation compartment is defined by the first AEM and the first CEM. If the GDE is GDE-2 as described herein, the CCM of the GDE shown in Figures 2(a) to (d) is placed in place of the first AEM shown in Figure 5. The CCM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the CCM. The base accumulation compartment is defined by the CCM and the first CEM. If the GDE is the GDE-3 as described herein, the first AEM shown in Figure 5 is omitted, and as a result, the cathode compartment and base storage compartment become a single compartment. Therefore, by using the GDE-3 without the first AEM, the cell becomes substantially a four-compartment membrane electrolytic cell. If the GDE is GDE-4 as described herein, the AEM of the GDE shown in Figures 4(a) to (d) is the first AEM shown in Figure 5. The first AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the first AEM. The base accumulation compartment is defined by the first AEM and the first CEM.

[0140] The first CEM defines the boundary between the base accumulation compartment and the salt depletion compartment. The base accumulation compartment is fluid-connected to the salt depletion compartment via the first CEM. The salt depletion compartment is defined by the first CEM and the second AEM. The second AEM defines the boundary between the salt depletion compartment and the acid accumulation compartment. The salt depletion compartment is fluid-connected to the acid accumulation compartment via the second AEM. The acid accumulation compartment is defined by the second AEM and the second CEM. The second CEM defines the boundary between the acid accumulation compartment and the anode compartment. The acid accumulation compartment is fluid-connected to the anode compartment via the second CEM.

[0141] The first AEM and the second AEM are described herein and may be identical or different. The first CEM and the second CEM are described herein and may be identical or different.

[0142] During operation, a salt solution containing positive and negative ions is supplied to the salt depletion section. An oxygen-containing gas is supplied to the GDE in the cathode section. When a voltage is applied between the anode and cathode, the positive ions in the salt solution move through the first CEM towards the negatively charged cathode section and remain in the base accumulation section because they cannot pass through the first AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3). Similarly, OH generated in the GDE -Anions move away from the negatively charged cathode toward the positively charged anode, passing through the first AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3), and thus accumulate in the base accumulation compartment. These OH2 ions, like positive ions, cannot pass through the first CEM and therefore remain in the base accumulation compartment. Thus, a base is formed in the base accumulation compartment. As shown in Figure 5, negative ions in the salt solution move toward the positively charged anode compartment through the second AEM, but cannot pass through the second CEM and therefore remain in the acid accumulation compartment. Protons are produced by the anodic reaction, and these protons are transported through the second CEM to the acid accumulation compartment. The protons combine with negative ions to form an acid.

[0143] When the salt solution contains LiCl, Li2SO4, Li3PO4, LiNO3, or LiI, LiOH is produced in the base accumulation compartment, and simultaneously, HCl, H2SO4, H3PO4, HNO3, and HI are produced in the acid accumulation compartment, respectively. Similarly, when the salt solution contains NaCl, Na2SO4, Na3PO4, NaNO3, or NaI, NaOH is produced in the base accumulation compartment, and simultaneously, HCl, H2SO4, H3PO4, HNO3, and HI are produced in the acid accumulation compartment, respectively. Furthermore, when the salt solution contains KCl, K2SO4, K3PO4, KNO3, or KI, KOH is produced in the base accumulation compartment, and simultaneously, HCl, H2SO4, H3PO4, HNO3, and HI are produced in the acid accumulation compartment, respectively.

[0144] Therefore, in one embodiment, the present disclosure relates to a membrane electrolytic cell for processing salt-containing solutions. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-1 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, the first anion exchange membrane configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base accumulation compartment via the opposite surface of the first anion exchange membrane, and the salt depletion compartment and the The membrane electrolytic cell comprises: a first cation exchange membrane interposed between the base accumulation compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the second anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0145] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the surface opposite to the first anion exchange membrane, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0146] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode comprising GDE-2 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; and a first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, which exchanges ions received from the salt depletion compartment. The electrolytic cell comprises: a first cation exchange membrane configured to exchange ions to the base accumulation compartment via the opposite surface of the membrane; an anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0147] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and through the opposite surface of the first cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0148] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment which, together with the cathode compartment, forms a single compartment, a salt depletion compartment and an acid storage compartment interposed between the cathode compartment and the anode compartment, wherein the salt depletion compartment is interposed between the base storage compartment and the acid storage compartment, and the acid storage compartment is interposed between the salt depletion compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-3 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a first cation exchange membrane interposed between the salt depletion compartment and the base storage compartment, wherein ions received from the salt depletion compartment are transferred via the opposite surface of the cation exchange membrane. The electrolytic cell comprises: a first cation exchange membrane configured to exchange ions to the base accumulation compartment; an anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0149] In another embodiment, the present disclosure relates to a method for producing a base product. The method includes receiving, in the membrane electrolysis cell described in the immediately preceding paragraph, a salt-containing solution containing positive and negative salt ions and a gas containing O2, and removing the base product from the membrane electrolysis cell. In the implementation of the method, the salt-containing solution is supplied to a salt depletion compartment, the positive salt ions pass through the first cation exchange membrane and move into the base accumulation compartment through the surface on the opposite side of the first cation exchange membrane, and the gas containing O2 is reduced at the cathode to produce OH - ions, and the OH - ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolysis cell.

[0150] (Four-compartment membrane electrolysis cell) In one embodiment, the membrane electrolysis cell includes four compartments as shown in FIG. 6. The membrane electrolysis cell includes a base accumulation compartment and a salt depletion compartment interposed between a cathode compartment and an anode compartment. The base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment.

[0151] The anode is housed within the anode compartment.

[0152] A cathode including a gas diffusion electrode (GDE) is housed within the cathode compartment and is as follows. · When the GDE is GDE-1 described herein, the CL of the GDE shown in FIGS. 1(a)-(d) is in direct contact with the first AEM shown in FIG. 6. In contrast, the AEM of the GDE shown in FIGS. 1(e)-(h) is the first AEM shown in FIG. 6. The first AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment through the first AEM. The base accumulation compartment is defined by the first AEM and the CEM. If the GDE is GDE-2 as described herein, the CCM of the GDE shown in Figures 2(a) to (d) is placed in place of the first AEM shown in Figure 6. The CCM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the CCM. The base accumulation compartment is defined by the CCM and CEM. If the GDE is the GDE-3 as described herein, the first AEM shown in Figure 6 is omitted, and as a result, the cathode compartment and base storage compartment become a single compartment. Therefore, by using the GDE-3 without the first AEM, the cell becomes substantially a three-compartment membrane electrolytic cell. If the GDE is GDE-4 as described herein, the AEM of the GDE shown in Figures 4(a) to (d) is the first AEM shown in Figure 6. The first AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the first AEM. The base accumulation compartment is defined by the first AEM and the CEM.

[0153] The CEM defines the boundary between the base accumulation compartment and the salt depletion compartment. The base accumulation compartment is fluidly connected to the salt depletion compartment via the CEM. The salt depletion compartment is defined by the CEM and the second AEM. The second AEM defines the boundary between the salt depletion compartment and the anode compartment. The salt depletion compartment is fluidly connected to the anode compartment via the second AEM.

[0154] The first AEM and the second AEM are described herein and may be identical or different. The CEM is also described herein.

[0155] During operation, a salt solution containing positive and negative ions is supplied to the salt depletion section. An oxygen-containing gas is supplied to the GDE in the cathode section. When a voltage is applied between the anode and cathode, the positive ions in the salt solution move through the CEM towards the negatively charged cathode section and remain in the base accumulation section because they cannot pass through the first AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3). Similarly, OH generated in the GDE - Anions move away from the negatively charged cathode toward the positively charged anode, passing through the first AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3), and thus accumulate in the base accumulation compartment. These OH2 ions, like positive ions, cannot pass through the CEM and therefore remain in the base accumulation compartment. Thus, a base is formed within the base accumulation compartment. As shown in Figure 6, negative ions in the salt solution move through the second AEM to the positively charged anode compartment.

[0156] If the salt solution contains (a) LiCl, LiBr, or LiI, (b) NaCl, NaBr, or NaI, or (c) KCl, KBr, or KI, then (a) LiOH, (b) NaOH, or (c) KOH will be produced in the base accumulation compartment, respectively. Simultaneously, depending on the input salt solution, HCl, HBr, or HI will be produced in the anode compartment, and furthermore, Cl2, Br2, or I2 may be produced, respectively.

[0157] When the salt solution contains Li2SO4, Li3PO4, or LiNO3, LiOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Similarly, when the salt solution contains Na2SO4, Na3PO4, or NaNO3, NaOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Furthermore, when the salt solution contains K2SO4, K3PO4, or KNO3, KOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively.

[0158] Accordingly, in one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-1 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, which receives ions from the catalyst layer of the gas diffusion electrode to the base accumulation compartment via the opposite surface of the first anion exchange membrane. The electrolytic cell comprises: a first anion exchange membrane configured for exchange; a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the second anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0159] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the surface opposite to the first anion exchange membrane, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0160] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment. The electrolytic cell comprises: a cation exchange membrane configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0161] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions move through the catalyst coating exchange membrane into the base accumulation compartment, and the OH -The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0162] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base accumulation compartment which together with the cathode compartment form a single compartment, a salt depletion compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-3 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, wherein ions received from the salt depletion compartment are transferred to the cation exchange membrane. The electrolytic cell comprises a cation exchange membrane configured to exchange ions to the base accumulation compartment via its opposite surface; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via its opposite surface; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0163] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base accumulation compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH -The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolytic cell.

[0164] (3-compartment membrane electrolytic cell) In one embodiment, the membrane electrolytic cell includes three compartments as shown in Figure 7. The membrane electrolytic cell includes a base accumulation compartment interposed between the cathode compartment and the anode compartment.

[0165] The anode is housed within the anode compartment.

[0166] The cathode, which includes a gas diffusion electrode (GDE), is housed within the cathode compartment as follows: If the GDE is GDE-1 as described herein, the CL of the GDE shown in Figures 1(a) to (d) is in direct contact with the AEM shown in Figure 7. In contrast, the AEM of the GDE shown in Figures 1(e) to (h) is the same AEM as shown in Figure 7. The AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the AEM. The base accumulation compartment is defined by the AEM and CEM. If the GDE is GDE-2 as described herein, the CCM of the GDE shown in Figures 2(a) to (d) is placed in place of the AEM shown in Figure 7. The CCM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the CCM. The base accumulation compartment is defined by the CCM and CEM. If the GDE is the GDE-3 as described herein, the AEM shown in Figure 7 is omitted, and as a result, the cathode compartment and base storage compartment become a single compartment. Therefore, by using the GDE-3 without the AEM, the cell becomes substantially a two-compartment membrane electrolytic cell. If the GDE is GDE-4 as described herein, the AEM of the GDE shown in Figures 4(a) to (d) is the AEM shown in Figure 7. The AEM defines the boundary between the cathode compartment and the base accumulation compartment. The cathode compartment is in fluid communication with the base accumulation compartment via the AEM. The base accumulation compartment is defined by the AEM and CEM.

[0167] The CEM defines the boundary between the base accumulation compartment and the anode compartment. The base accumulation compartment is in fluid communication with the anode compartment via the CEM.

[0168] CEM and AEM are as described herein.

[0169] During operation, a salt solution containing positive and negative ions is supplied to the anode compartment. An oxygen-containing gas is supplied to the GDE in the cathode compartment. When a voltage is applied between the anode and cathode, the positive ions in the salt solution move through the CEM towards the negatively charged cathode compartment and remain in the base accumulation compartment because they cannot pass through the AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3). Similarly, OH generated in the GDE - Anions move away from the negatively charged cathode toward the positively charged anode, passing through the AEM (GDE-1 and GDE-4), CCM (GDE-2), or catalyst layer (GDE-3), and thus accumulate in the base accumulation compartment. These OH2 ions, like positive ions, cannot pass through the CEM and therefore remain in the base accumulation compartment. Thus, bases are formed within the base accumulation compartment.

[0170] If the salt solution contains (a) LiCl, LiBr, or LiI, (b) NaCl, NaBr, or NaI, or (c) KCl, KBr, or KI, then (a) LiOH, (b) NaOH, or (c) KOH will be produced in the base accumulation compartment, respectively. Simultaneously, depending on the input salt solution, HCl, HBr, or HI will be produced in the anode compartment, and furthermore, Cl2, Br2, or I2 may be produced, respectively.

[0171] When the salt solution contains Li2SO4, Li3PO4, or LiNO3, LiOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Similarly, when the salt solution contains Na2SO4, Na3PO4, or NaNO3, NaOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Furthermore, when the salt solution contains K2SO4, K3PO4, or KNO3, KOH is produced in the base accumulation compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively.

[0172] Therefore, in one embodiment, the present disclosure relates to a membrane electrolytic cell for processing salt-containing solutions. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-1 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, an anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base storage compartment via the opposite surface of the anion exchange membrane, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0173] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the anion exchange membrane and move into the base accumulation compartment via the surface opposite to the anion exchange membrane, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0174] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-2 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet disposed within the cathode compartment into which a gas containing O2 is introduced so as to contact the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0175] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base storage compartment to form the base product, and the base product is removed from the base storage compartment.

[0176] In another embodiment, the disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, a base storage compartment which together with the cathode compartment form a single compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising GDE-3 as described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet disposed within the cathode compartment into which a gas containing O2 is introduced so as to contact the gas diffusion electrode, and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0177] In another embodiment, the present disclosure relates to a method for producing a base product. The method comprises the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the base storage compartment, and the gas containing O2 is reduced at the cathode to form OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, and the base product is removed from the membrane electrolytic cell.

[0178] (Two-compartment membrane electrolytic cell) In one embodiment, the membrane electrolytic cell includes two compartments, as shown in Figure 8. The membrane electrolytic cell includes a cathode compartment and an anode compartment. The cathode compartment and the anode compartment are in fluid communication via a CEM. The CEM is described herein.

[0179] The anode is housed within the anode compartment.

[0180] The cathode containing the GDE shown in Figures 1(a) to (d) is housed within the cathode compartment. In this embodiment, the cathode compartment also functions as a base accumulation compartment in the region between the CEM and the CL of the GDE.

[0181] During operation, a salt solution containing positive and negative ions is supplied to the anode compartment. An oxygen-containing gas is supplied to the GDE in the cathode compartment. When a voltage is applied between the anode and cathode, positive ions move through the CEM towards the negatively charged cathode compartment. OH is generated in the GDE. -Since the anion cannot pass through the CEM, it remains in the cathode compartment. Therefore, the base is formed within the cathode compartment.

[0182] If the salt solution contains (a) LiCl, LiBr, or LiI, (b) NaCl, NaBr, or NaI, or (c) KCl, KBr, or KI, then (a) LiOH, (b) NaOH, or (c) KOH will be produced in the cathode compartment, respectively. Simultaneously, depending on the input salt solution, HCl, HBr, or HI will be produced in the anode compartment, and furthermore, Cl2, Br2, or I2 may be produced, respectively.

[0183] When the salt solution contains Li2SO4, Li3PO4, or LiNO3, LiOH is produced in the cathode compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Similarly, when the salt solution contains Na2SO4, Na3PO4, or NaNO3, NaOH is produced in the cathode compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively. Furthermore, when the salt solution contains K2SO4, K3PO4, or KNO3, KOH is produced in the cathode compartment, and simultaneously H2SO4, H3PO4, or HNO3 are produced in the anode compartment, respectively.

[0184] Accordingly, in one embodiment, the present disclosure relates to a membrane electrolytic cell for processing a salt-containing solution. The membrane electrolytic cell comprises an anode compartment, a cathode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, a cathode comprising the GDE-1 described herein, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, a cation exchange membrane interposed between the anode compartment and the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the anode to the opposite surface of the cation exchange membrane, an inlet for supplying the salt-containing solution to the anode compartment, a gas inlet for introducing a gas containing O2 into contact with the gas diffusion electrode, and at least one outlet from which the products of the salt solution are removed from inside the membrane electrolytic cell.

[0185] Another embodiment relates to a method for producing a base product. The method includes the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell as described in the preceding paragraph, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and through the opposite surface of the cation exchange membrane into the cathode compartment, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions combine with the positive salt ions to form the base product, and the base product is removed from the cathode compartment.

[0186] Anion exchange membrane (AEM) An anion exchange membrane (AEM) is a membrane that is permeable to anions. An AEM contains a polymer having multiple positively charged cationic groups bonded to at least a portion of the polymer backbone. The cationic functional groups may be bonded to the backbone via extended side chains or directly.

[0187] Non-limiting examples of polymer backbones for anion exchange membranes include polyalkylenes such as polyethylene (PE); polyfluorene (PFN), poly(arylene ether) (PAE); polysulfone, poly(arylene ethersulfone) (PAES), polyetherketone (PEK), polyetherimide (PEI), poly(etheroxadiazole), poly(phenylene oxide) (PPO); poly(vinyl benzyl) (PVB); polyphenylene (PPN); perfluoroestroides (PF); polybenzimidazole (PBI); polystyrene (PS); and polyphosphazenes.

[0188] Non-limiting examples of cationic functional groups include primary, secondary, tertiary, or quaternary ammonium compounds; heterocyclic cations such as imidazolium or pyridinium; guanidinium; phosphonium; sulfonium; and metal cations.

[0189] Non-limiting examples of anion exchange membranes (AEMs) include: (10a) Fumasep TM FAA-based AEMs (e.g., FAA, FAA-3-20, FAA-3-25, FAA-3-30, FAA-3-50, FAA-3-PE-30, FAA-3-PK-75, FAA-3-PK-130, FAA-3-PK-150), (10b) Fumasep TM FAB-based AEMs (e.g., FAB-PK-75, FAB-PK-130), (10c) Fumasep TM FAD-based AEMs (e.g., FAD-55, FAD-PET-75), (10d) Fumasep TM FAM-based AEM (e.g., FAM), (10e) Fumasep TM FAAM-based AEMs (e.g., FAAM-10, FAAM-15, FAAM-20, FAAM-40, FAAM-PK-75), (10f) Fumasep TMFAP-based AEMs (e.g., FAP-330, FAP-450, FAP-330-PE, FAP-330-PE, FAP-420-PE, FAP-375-PP), (10g) Fumasep TM FAPQ-based AEMs (e.g., FAPQ-330, FAPQ-8130-PK, FAPQ-375-PP), (10h) Fumasep TM FAS-based AEMs (e.g., FAS-50, FAS-30, FAS-PET-75, FAS-PE-130), (10i) Neosepta TM AEM (e.g., ACN, ACS, AFN, AFX, AHA, AHO, AID, AMX, ASE, AXP-D), (10j) ORION TM AEM (e.g., TM1, CMX), (10k) Xergy Xion TM Pension TM AEM (e.g. Pention-AEM-18-05, Pention-AEM-18-10, Pention-AEM-18-20, Pention-AEM-18-30, Pention-AEM-35-05, Pention-AEM-35 -10, Pention-AEM-35-20, Pention-AEM-35-30, Pention-AEM-72-05, Pention-AEM-72-10, Pention-AEM-72-20, Pention-AEM-72-30), (10L) PiperION TM AEM (e.g., PiperION anion exchange membrane - 15 micron, PiperION anion exchange membrane - 20 micron, PiperION anion exchange membrane - 40 micron, PiperION anion exchange membrane - 60 micron, PiperION anion exchange membrane - 80 micron), (10m) RALEX TM AEM (e.g., AMHPES, AMHPP), (10n)SELEMION TM AEM (e.g. AAV, AAVN, AHO, AMT, AMV, AMVN, ASV, ASVN, DSV, DSVN), (10o) Sustainion(R) AEM (e.g., B22-50, E28-50, E30-50, X37-50, X37-60, X37-FA, X37-T, X37-TZ), and (10p) Ionomr AEM (e.g., Aemion).

[0190] (Cation exchange membrane (CEM)) A cation exchange membrane (CEM) is a membrane that is permeable to cations. In one embodiment, the CEM may be a monovalent cation selective membrane. In another embodiment, the CEM may be a lithium selective membrane.

[0191] CEM may include a polymer having multiple negatively charged anionic groups bonded to at least a portion of the polymer backbone. The anionic functional groups may be bonded to the backbone via extended side chains or directly.

[0192] Non-limiting examples of polymer backbones for cation exchange membranes include polyalkylenes such as polyethylene (PE) or polypropylene; polyfluorene (PFN), poly(arylene ether) (PAE); polysulfone, poly(arylene ethersulfone) (PAES), polyetherketone (PEK), polyetherimide (PEI), poly(etheroxadiazole), poly(phenylene oxide) (PPO); poly(vinyl benzyl) (PVB); polyphenylene (PPN); perfluoroestroides (PF); polybenzimidazole (PBI); polystyrene (PS); and polyphosphazenes.

[0193] Non-limiting examples of anionic functional groups include sulfonates such as perfluorosulfonates; carboxylates; phosphonates; and phenolate anions.

[0194] Non-limiting examples of cation exchange membranes include: (11a) Aquivion(R) CEM (e.g., E87-05S, E98-05S, E98-09S, E98-15S), (11b)Fumasep TM CEM(F-930-RFD, F-1075-PK, F-1850, F-10120, F-10120-P K, F-10150-PF, F-10270-PTFE-e, FS-720, FS-950, FS-990-PK, F S-9100-PK, FKB, FKB-PK-130, FKD-PET-75, FKD-PK-75, FKE-50 FKL-PK-130, FKM, FKS-30, FKS-50, FKS-PET-75, FKS-PET-130) (11c)Full TM CEM(F-14100, F-930, F-930-RFS, FS-715-RFS, FS-930, FS-930-RFS, F-950) (11d)Nafion TM CEM (N115, N117, N324, N417, N424, N438, N551, N1110) (11e)Neosepta TM CEM (CMB, CMX, CSE, CXP-S) (11f)SELEMION TM CEM (CMD, CMF, CMTE, CMV, CMVN, CSO) (11g)Exergy Xion TMCEM (e.g., PEM-Nafion-1000-05, PEM-Nafion-1000-10, PEM-Nafion-1000-20, PEM-Nafion-1000-30, PEM-Nafion-1000- 50, PEM-Nafion-1100-05, PEM-Nafion-1100-10, PEM-Nafion-1100-20, PEM-Nafion-1100-30, PEM-Nafion-1100-50, PEM -Aquivion-720-05, PEM-Aquivion-720-10, PEM-Aquivion-720-20, PEM-Aquivion-720-30, PEM-Aquivion-720-50, PEM -Aquivion-830-05, PEM-Aquivion-830-10, PEM-Aquivion-830-20, PEM-Aquivion-830-30, PEM-Aquivion-830-50), and (11h) Ionomr TM CEM (e.g., Permion).

[0195] When the salt solution processed in a membrane electrolytic cell contains a lithium salt, the CEM on which lithium ions move may be (11i) lithium-selective. Non-limiting examples of lithium-selective CEMs include the membranes described in WO2021026607 and WO2022173852, the disclosures of which are incorporated herein by reference.

[0196] The various specific embodiments of the membrane electrolytic cell (MEC) relating to this disclosure include the membrane electrolytic cell defined in the following lines, where each item is a group number as defined above: [Two-compartment membrane electrolytic cell] [Table 2]

[0197] [3-compartment membrane electrolytic cell] [Table 3-1] [Table 3-2]

[0198] [4-compartment membrane electrolytic cell] [Table 4-1] [Table 4-2] [Table 4-3]

[0199] [5-compartment membrane electrolytic cell] [Table 5-1] [Table 5-2] [Table 5-3] [Table 5-4] [Table 5-5]

[0200] The flow rates of the salt solution in the membrane electrolytic cell described herein are 0.5-5 L / min, 0.5-4.8 L / min, 0.5-4.6 L / min, 0.5-4.4 L / min, 0.5-4.2 L / min, 0.5-4.0 L / min, 0.5-3.8 L / min, 0.5-3.6 L / min, 0.5-3.4 L / min, 0.5-3.2 L / min, 0.5-3.0 L / min, 0.5-2.8 L / min, and 0.5-2. The flow rate may be in the range of 6 L / min, 0.5-2.4 L / min, 0.5-2.2 L / min, 0.5-2.0 L / min, 0.5-1.8 L / min, 0.5-1.6 L / min, 0.5-1.4 L / min, 0.5-1.2 L / min, 0.5-1.0 L / min, 1.0-3.0 L / min, 1.2-2.8 L / min, 1.4-2.6 L / min, 1.6-2.4 L / min, or 1.8-2.2 L / min.

[0201] The flow rate of the oxygen-containing gas in the membrane electrolytic cell described herein may be in the range of 5-25 L / min, 5-23 L / min, 5-21 L / min, 5-19 L / min, 5-17 L / min, 5-15 L / min, 5-13 L / min, 5-11 L / min, 5-9 L / min, 5-7 L / min, 7-25 L / min, 9-25 L / min, 11-25 L / min, 13-25 L / min, 15-25 L / min, 17-25 L / min, 19-25 L / min, 21-25 L / min, 23-25 ​​L / min, 7-23 L / min, 9-21 L / min, 11-19 L / min, or 13-17 L / min.

[0202] The temperature of the salt solution in the membrane electrolytic cell described herein may be in the range of 40-70°C, 40-65°C, 40-60°C, 40-55°C, 40-50°C, 40-45°C, 45-70°C, 50-70°C, 55-70°C, 60-70°C, 65-70°C, 45-65°C, or 50-60°C.

[0203] Integration of membrane electrolytic cells with gas diffusion electrodes into lithium recovery processes Figure 9 shows a salar brine lithium recovery process that can utilize a membrane electrolytic cell (MEC) as described herein, together with a gas diffusion electrode (GDE) as described herein. As shown in Figure 9, the sodium chloride salt extracted from the evaporation step in the lithium brine recovery process is supplied to the membrane electrolytic cell as feed brine. The feed brine is then depleted as it passes through the cell. This depletion removes Na+ ions and OH - These ions are generated by the movement of ions from the salt-depleted compartment to the base-accumulating compartment and the acid-accumulating compartment, respectively.

[0204] The ions that move from the salt-depleted section depend on the ion species contained in the feed brine supplied to the membrane electrolytic cell. Therefore, the desalination water removed from the salt-depleted section can be reconcentrated using a salt (NaCl) stockpile readily available from the salt precipitated from the evaporation ponds of Lake Salar and recycled as feed brine. The concentration of the feed brine plays a crucial role in ensuring mass transfer of the feed brine and in supplying ions for acid and base formation. While the membrane electrolytic cell can operate even with a feed brine salt concentration as low as 0.1% by weight, it is preferable to operate it at the maximum available feed brine concentration.

[0205] The concentrations of the generated acids and bases extracted from the acid and base accumulation compartments, respectively, can be adjusted according to the requirements of each process. Using the membrane electrolytic cell and GDE described herein, caustic soda (NaOH) concentrations ranging from 5 to 20% by weight can be achieved. Typical uses of the NaOH generated in the membrane electrolytic cell in the salar brine lithium recovery operation, as shown in Figure 9, include, but are not limited to, the following: • Neutralization and pH adjustment after the solvent extraction process for solvent reuse; • Alkaline supply for precipitation and hardness removal; • Regeneration of ion exchange resins used for hardening and metal removal; • Conversion of lithium carbonate to lithium hydroxide through a caustic process.

[0206] All of the above processes require a caustic (NaOH) concentration in the range of 5–20% by weight, which is achievable with a membrane electrolytic cell.

[0207] The following are some non-limiting typical uses of hydrochloric acid that can be produced by membrane electrolytic cells during the lithium brine recovery process: • pH adjustment for boron removal during solvent extraction process; • Regeneration of ion exchange resins used for hardening and metal removal; • Conversion from lithium carbonate to lithium chloride.

[0208] The hydrochloric acid concentration for the above applications is in the range of 4-12% by weight, which can be achieved by a membrane electrolytic cell.

[0209] Figure 10 shows a lithium rock mining process incorporating a membrane electrolytic cell along with the GDE described herein. As shown in Figure 10, sodium sulfate (Na2SO4) salt, the largest byproduct in lithium rock mining operations, can be used as a brine supply to the membrane electrolytic cell. As shown in Figure 10, supplying Na2SO4 to the membrane electrolytic cell generates NaOH as a base and H2SO4 as an acid, which can be reused (recycled) as reagents in the lithium recovery process.

[0210] Sulfuric acid (H2SO4) is a key reagent required for extracting lithium from ore in the acid roasting process. As shown in Figure 10, this chemical can be recycled from sodium sulfate, a readily available by-product in lithium hard rock mining operations.

[0211] Similarly, the resulting sodium hydroxide can be used for a variety of purposes throughout the lithium production process. Examples of non-limited uses of sodium hydroxide in lithium rock mining operations are listed below: • Alkaline supply for precipitation and hardness removal; • Regeneration of ion exchange resins used for hardening and metal removal; • Conversion of lithium sulfate to lithium hydroxide by adding NaOH during the process.

[0212] All of the above processes require NaOH concentrations in the range of 5–20% by weight, which is achievable with a membrane electrolytic cell.

[0213] Figure 11 shows a first embodiment of on-site production of LiOH and HCl from LiCl using the membrane electrolytic cell and GDE described herein. In one embodiment (not shown), the membrane electrolytic cell is used to convert LiCl to LiOH in a lithium recovery process from salar brine. As shown in Figure 11, the brine supply to the membrane electrolytic cell is a LiCl solution, which is supplied to the salt depletion compartment (not shown) of the membrane electrolytic cell. Oxygen gas, preferably in the form of air, is supplied to the cathode. The oxygen or air may optionally be humidified, for example, by bubbling the gas in water before supplying it to the cathode. The air may optionally be purified. As shown, the products from the cell are LiOH, taken out from the base accumulation compartment (not shown), and HCl, taken out from the acid accumulation compartment (not shown). Demineralized water may optionally be taken out of the cell, but this stream is not shown in Figure 11. Whether or not demineralized water is taken out of the cell depends on the concentration of the supply brine, i.e., the LiCl aqueous solution, and the desired concentrations of the LiOH and HCl produced.

[0214] Similarly, instead of removing desalinated water, water may be optionally supplied to the cell. Whether or not water is supplied to the cell depends on the concentration of the supply brine, i.e., the LiCl aqueous solution, and the desired concentrations of the LiOH and HCl produced. As shown in Figure 11, in this embodiment, HCl may be used to regenerate the ion exchange resin used to remove Ca, Mg, Na, and K from the LiCl process stream flowing into the cell. HCl may also be used to regenerate the ion exchange resin in the boron removal step, which is usually performed after the evaporation / precipitation step in the early stages of the process. HCl may also be used to adjust the pH of the process stream that produces CO2, as shown in Figure 11. The produced CO2 combines with a portion of the LiOH product stream to produce a stream containing LiOH and Li2CO3. The LiOH / Li2CO3 stream may be supplied to the precipitation step to remove Ca and Mg, as shown in Figure 11. Importantly, since LiOH is the target product, not all of the LiOH product stream is used in this precipitation step. However, the ability to use LiOH in this way significantly reduces the need to purchase bases such as NaOH or Na2CO3 to remove precipitates of Ca and Mg.

[0215] For reference, based on tests using a 6% LiCl stream as brine supply, when using air in the oxygen depolarized cathode (ODC), approximately 150-250 kWh / m³ is required to reduce the total salt content to 3%. 3 LiCl brine is required.

[0216] Figure 12 shows a second embodiment in which the membrane electrochemical cell with GDE described herein is applied to lithium recovery from salar brine. In this embodiment as well, an aqueous LiCl solution is used as the brine supply to the membrane electrolytic cell. In this embodiment, as in the first embodiment, LiCl is converted to LiOH using the membrane electrolytic cell. The aqueous LiCl solution is supplied to the salt depletion compartment of the membrane electrolytic cell. Oxygen gas, preferably in the form of air, is supplied to the cathode. The oxygen or air may optionally be humidified, for example, by bubbling the gas in water before supplying it to the cathode. The air may optionally be purified. As shown in the figure, the products from the cell are LiOH, taken out from the base accumulation compartment (not shown), and HCl, taken out from the acid accumulation compartment (not shown). As in the first embodiment, desalinated water may optionally be taken out of the cell, but this stream is not shown in Figure 12.

[0217] Whether or not demineralized water is removed from the cell depends on the concentration of the supply brine, i.e., the LiCl aqueous solution, and the desired concentrations of the LiOH and HCl produced. Similarly, water may be optionally supplied to the cell instead of removing demineralized water. Whether or not water is supplied to the cell depends on the concentration of the supply brine, i.e., the LiCl aqueous solution, and the desired concentrations of the LiOH and HCl produced. In this embodiment, all of the produced LiOH is removed, i.e., there is no recycling stream containing LiOH.

[0218] However, as in the first embodiment, the HCl stream may be recycled and used in the lithium recovery process. As shown in Figure 12, the HCl is used to regenerate the ion exchange resin, which is used to remove Ca and Mg from the process stream immediately before it is supplied to the membrane electrolytic cell as a feed brine. The generated HCl may also be used to regenerate the ion exchange resin in boron (B) removal, which is performed after the precipitation step.

[0219] Figure 13 shows a third embodiment of a lithium production process using a membrane electrolytic cell with GDE as described herein. In this process embodiment, a mixed brine solution containing both LiCl and NaCl is supplied to the membrane electrolytic cell. The cell then produces a mixed solution of HCl and LiOH and NaOH. This LiOH and NaOH mixture is supplied to a crystallization / separation step to produce crystallized LiOH and a mixed solution of NaOH and LiOH having a lower LiOH concentration than the LiOH and NaOH mixture supplied to the crystallization / separation step. As shown in Figure 13, this process is similar to the processes in Figures 9 and 11, but incorporates and utilizes a membrane electrolytic cell in an existing operation to produce LiOH from salar brine. As an alternative embodiment, the membrane electrolytic cell can also be applied to other waste or recycling lithium chloride streams generated in conventional lithium operations that do not contain sodium, in which case lithium chloride can be converted to lithium hydroxide and hydrochloric acid.

[0220] The process is as follows: Step 1: A mixed stream of lithium chloride and sodium chloride, generated from a conventional salar brine treatment operation, is supplied to a membrane electrolytic cell (electrochemical cell) to produce a mixed lithium hydroxide-sodium hydroxide solution. Step 2: The lithium hydroxide-sodium hydroxide mixture is sent to a crystallization / separation apparatus and separated due to the large difference in solubility between the two salts. That is, NaOH is significantly more soluble in water than LiOH. The crystallization / separation apparatus may evaporate the water and optionally re-condense it, or cool the mixed solution of NaOH and LiOH to precipitate some of the LiOH. A more common method is evaporation of water. The lithium hydroxide crystallizes, and the sodium hydroxide remains in the solution. The crystallized lithium hydroxide is ready for market. Step 3: Some lithium hydroxide remains in the solution along with sodium hydroxide and is recycled back into the process for use in the precipitation step. Step 4: Some of the lithium hydroxide and sodium hydroxide react with carbon dioxide to produce a mixed stream of lithium carbonate and sodium carbonate, which is recycled throughout the process for further precipitation, as shown in Figure 13.

[0221] By combining these processes, integrating an electrochemical cell (membrane electrolytic cell) into the overall process of recovering LiOH from salar brine creates a complete or nearly complete closed loop for sodium hydroxide, sodium carbonate, and lithium carbonate.

[0222] Next, referring to Figure 14, a fourth embodiment is shown in which the membrane electrolytic cell with GDE described herein is applied to a lithium production process. As shown in Figure 14, in a process for producing lithium from lithium-containing ore, Li2SO4 is converted to LiOH using the membrane electrolytic cell. However, those skilled in the art will understand that the brine supply stream containing the aqueous Li2SO4 solution does not necessarily have to come from a lithium ore-derived process.

[0223] In certain brine recovery processes, it is desirable to convert the Li2SO4 solution to LiOH, and a membrane electrolytic cell can also be used in such processes. As shown in Figure 14, an aqueous Li2SO4 solution is used in the membrane electrolytic cell. Also, as in other embodiments, an oxygen-containing gas stream is supplied to the cell. This stream is preferably air and is supplied to the cathode. The oxygen or air can optionally be humidified, for example, by bubbling the gas in water before supplying it to the cathode. The air may optionally be purified. As shown in the figure, the products from the cell are LiOH taken out from the base storage compartment (not shown) and H2SO4 taken out from the acid storage compartment (not shown).

[0224] Similar to the first and second embodiments, demineralized water may be optionally removed from the cell, although this stream is not shown in Figure 14. Whether or not demineralized water is removed from the cell depends on the concentration of the feed brine, i.e., the Li2SO4 aqueous solution, and the desired concentrations of the LiOH and H2SO4 produced. Similarly, instead of removing demineralized water, water may be optionally supplied to the cell. Whether or not water is supplied to the cell depends on the concentration of the feed brine, i.e., the Li2SO4 aqueous solution, and the desired concentrations of the LiOH and H2SO4 produced.

[0225] In this embodiment, both LiOH and H2SO4 are recycled into the lithium recovery process, thereby reducing, at least partially, the need to purchase additional reagents. Importantly, since LiOH is the desired final product, only a portion of the generated LiOH is recycled. H2SO4 is used in the acid roasting process in ore production to produce a Li2SO4 brine solution after the water leaching process. A portion of the generated LiOH can be used to precipitate and remove Ca and Mg from the Li2SO4 brine solution after the water leaching process, as shown in Figure 13.

[0226] Figure 15 shows an exemplary embodiment of applying the membrane electrolytic cell with GDE described herein to a closed-loop process. In this process, lithium carbonate (Li2CO3) produced by other methods, such as lithium carbonate produced by brine precipitation using sodium carbonate, or lithium carbonate produced from jadalite (LiNaSiB3O7OH), is dissolved in hydrochloric acid to form a lithium chloride solution, which is then converted to LiOH. The process shown in Figure 15 is as follows: Step 1: Convert lithium carbonate produced by other methods into lithium chloride by dissolving it in hydrochloric acid. Step 2: Treat lithium chloride in an electrochemical cell to produce lithium hydroxide and hydrochloric acid. Step 3: Recycle the generated hydrochloric acid and reuse it to convert lithium carbonate to lithium chloride, thereby creating a fully or substantially closed-loop system.

[0227] Similarly, the process shown in Figure 15 can also be carried out using sulfuric acid instead of hydrochloric acid, as follows: Step 1: Convert lithium carbonate produced by other methods into lithium sulfate by dissolving it in sulfuric acid. Step 2: Treat lithium sulfate in an electrochemical cell to produce lithium hydroxide and sulfuric acid. Step 3: Recycle the generated sulfuric acid and reuse it to convert lithium carbonate to lithium sulfate, thereby creating a fully or substantially closed-loop system.

[0228] As shown in the following two exemplary embodiments (Figures 16 and 17), the membrane electrolytic cells with GDE described herein can also be used in lithium recovery processes incorporating ion exchange resins. These ion exchange resins may be used to directly generate LiOH, or to recycle and / or recover other ion species in the lithium recovery process. The advantages of these embodiments (and all embodiments of membrane electrolytic cells disclosed herein) are wide-ranging in terms of reductions in operating costs and capital investment costs.

[0229] As described above, lithium hydroxide is produced by processing lithium-enriched brines such as Salar brine through a wide range of processes. The water in the brine is evaporated over a period of 6 to 18 months, concentrating the lithium chloride concentration in the solution to 5% by weight or more, and precipitating and removing sodium, calcium, and magnesium salts, which generally have lower solubility than LiCl.

[0230] Subsequently, the lithium chloride-enriched brine must be subjected to various purification processes. These purification processes may include, for example, boron removal by solvent or other methods, removal of calcium and magnesium by adding lime (calcium oxide and / or calcium hydroxide) and caustic soda, soda ash and / or sodium bicarbonate, and further removal of calcium and magnesium by adding soda ash, i.e., sodium carbonate (Na2CO3). These processes produce a mixed stream of lithium chloride and sodium chloride, to which lithium carbonate precipitates upon addition of additional soda ash. The lithium carbonate can then be crystallized. Currently, this crystallized lithium carbonate is often transported to lithium hydroxide production plants and converted to lithium hydroxide by adding calcium hydroxide. The lithium hydroxide is then crystallized and sold. All of these processes require multiple process equipment, and it is clear that procuring and maintaining this equipment involves significant capital investment and ongoing operating costs.

[0231] By using an ion exchange resin that selectively adsorbs or binds lithium, lithium can be selectively adsorbed from salal brine (or other sources) without the need for time-consuming evaporation or the removal of boron, calcium, magnesium, etc., thus eliminating many of these steps. For example, an ion exchange resin that selectively binds lithium and produces lithium chloride by desorbing lithium from the resin using HCl can be used. The membrane electrolytic cell described herein can convert this lithium chloride into lithium hydroxide and hydrochloric acid, the hydrochloric acid is recycled into the ion exchange resin, and the desired lithium hydroxide is recovered.

[0232] In another embodiment, lithium sulfate can be produced by using an ion exchange resin for selectively adsorbing lithium and regenerating the resin with sulfuric acid. Similarly, the obtained lithium sulfate is supplied to an electrolytic cell to produce lithium hydroxide and sulfuric acid. The generated sulfuric acid is recycled to the ion exchange resin and used to produce further lithium sulfate, while the desired lithium hydroxide is recovered.

[0233] The use of this ion exchange resin can reduce the significant capital investment and operating expenses and costs associated with lithium evaporation tanks and related downstream transport.

[0234] Eliminating evaporation ponds also allows for the conservation of water lost into the atmosphere during the evaporation process. Producers can return the lithium-free brine to the Salar brine reservoir, thereby conserving water that would otherwise be lost through evaporation. This feature is extremely important from both an environmental and legal perspective. For example, in Chile, where the majority of the world's lithium brine is located, there are strict limits on water usage and the amount of brine that lithium producers can pump. The purpose of these regulations is to conserve the scarce water resources in the Salar Desert region of Chile. These restrictions effectively limit the amount of lithium that producers can produce. However, by returning the lithium-free brine to the reservoir through an ion exchange process, the net amount of brine pumped is significantly reduced, allowing producers to increase lithium production without exceeding government-imposed limits on Salar brine pumping or water usage in operations. Furthermore, using ion exchange resins in the lithium recovery process reduces the time loss caused by the slow evaporation process. Importantly, it also eliminates the need to purchase reagents required for the precipitation and removal of calcium and magnesium.

[0235] The greatest cost associated with the direct production of lithium using ion exchange resins lies in the procurement of hydrochloric acid (HCl) required to desorb or dissociate lithium ions from the active site of the ion exchange resin and regenerate the resin. The electrochemical cell described herein can convert lithium chloride to lithium hydroxide and hydrochloric acid, thereby eliminating the need to procure reagents required to convert lithium chloride to lithium carbonate and then to lithium hydroxide, while simultaneously generating HCl, which is essential for extracting lithium from the ion exchange resin. Therefore, the entire process from the evaporation of lithium chloride to the production of lithium carbonate, and further from lithium carbonate to lithium hydroxide to produce lithium hydroxide for battery applications, can be simplified to a process using only ion exchange resin and an electrochemical cell.

[0236] Furthermore, another exemplary application of membrane electrolytic cells in a process using ion exchange resins that directly adsorb lithium from brine is a process in which the ion exchange resins are placed in a desert where salar brine is pumped up, while the membrane electrolytic cells are installed in a separate location. In this exemplary process, the ion exchange resins are removed and transported to the site where the membrane electrolytic cells are installed, where they are regenerated with HCl to produce LiOH. The ion exchange resins are then returned to the brine site in the desert. Thus, the used ion exchange resins move in one direction, and the regenerated ion exchange resins move in the opposite direction. Therefore, in any of the exemplary processes shown in Figures 15, 16, or 17 below, the membrane electrolytic cells with GDEs described herein can be installed in a location separate from the ion exchange resins.

[0237] A suitable non-limiting example of such an ion exchange resin is a resin that selectively binds lithium or other precious metals based on the pH of the solution. For example, the resin may bind lithium in acidic conditions but not in alkaline conditions, or vice versa. This allows for the regeneration of the resin and the extraction of lithium from it. That is, the manufacturer can regenerate the resin and extract lithium from it. The membrane electrolytic cell generates a suitable pH solution for removing the bound ions by supplying HCl or NaOH. Such an ion exchange resin contains H n M n O n This may also include composite metal resins represented as (H is hydrogen, M is a metal species, O is oxygen, and n is an integer). Non-limiting examples include LiAlO2 and LiCuO2.

[0238] The following two embodiments illustrate how the membrane electrolytic cell with GDE described herein may be incorporated into a lithium recovery process that directly generates LiOH using an ion exchange resin.

[0239] Figure 16 shows an exemplary embodiment of the use of a membrane electrolytic cell in a lithium production process for selectively adsorbing Li from lithium brine using an ion exchange resin. This lithium brine does not necessarily have to be salar brine; for example, it may be produced water from oil and gas operations, geothermal brine that may contain lithium, naturally occurring saltwater aquifers, or brine obtained from lithium-ion battery recycling processes. As shown in Figure 16, the membrane electrolytic cell produces marketable LiOH while simultaneously generating HCl, which is used to regenerate the ion exchange resin by removing Li (as LiCl) from it. The generated LiCl is supplied to the membrane electrolytic cell to produce the desired LiOH. In an alternative embodiment, lithium sulfate may be produced using sulfuric acid and then processed in the membrane electrolytic cell to produce the desired lithium hydroxide. The process steps are as follows: Step 1: Treat the lithium-containing brine or solution with an ion exchange resin or other adsorbent to adsorb lithium from the brine or solution. Step 2: Regenerate the lithium-containing resin beads or adsorbent with hydrochloric acid to produce a lithium chloride solution. The resin or adsorbent is regenerated into a protonated form by HCl. Alternatively, the resin may be regenerated with sulfuric acid. Step 3: Treat the lithium chloride solution in an electrochemical cell to produce lithium hydroxide and hydrochloric acid. Alternatively, treat the lithium sulfate solution in an electrochemical cell to produce lithium hydroxide and sulfuric acid. Step 4: Sell the lithium hydroxide to the market or remove it from the process, and recycle the hydrochloric acid back to Step 2.

[0240] Figure 17 illustrates another exemplary application of the membrane electrolytic cell disclosed herein, in which lithium-containing brine undergoes a boron removal step before being sent to the ion exchange resin and membrane electrolytic cell. Similar to Figure 16, in this exemplary embodiment, the post-boron removal process steps are as follows: Step 1: Treat the lithium-containing brine or solution with an ion exchange resin or other adsorbent to adsorb lithium from the brine or solution. Step 2: Regenerate lithium-containing ion exchange resin beads or other suitable lithium adsorbents with hydrochloric acid to produce a lithium chloride solution. The resin or adsorbent is regenerated into a protonate form by HCl. The solution from which lithium has been removed can be returned to the salar reservoir or pond. As mentioned above, particularly in Chile, there are restrictions on water resource conservation regarding the amount of salar brine that can be pumped from natural reservoirs. By returning the lithium-removed solution to the reservoir, producers can produce more lithium without exceeding the legal limits on the amount of brine that can be pumped. Step 3: The lithium chloride solution is treated in a membrane electrochemical cell disclosed herein to produce lithium hydroxide and hydrochloric acid. Alternatively, lithium sulfate may be treated in a membrane electrochemical cell to produce lithium hydroxide and sulfuric acid. Step 4: Sell the lithium hydroxide to the market or remove it from the process, and recycle the hydrochloric acid or sulfuric acid back to Step 2.

[0241] In the process shown in Figure 17, air and electricity are supplied to the membrane electrolytic cell. Therefore, the overall reaction at the anode and cathode during electrolysis is as follows: Anode: 2H2O → O2 + 4H + +4e - Cathode: O2 + 2H2O + 4e - →4OH -

[0242] As shown in the following exemplary embodiment (Figure 18), the membrane electrolytic cell can also be used in alkali (e.g., LiOH) recovery processes incorporating solvent extraction (SX) methods.

[0243] The SX method is used to separate compounds based on the difference in relative solubility in two immiscible liquid phases, namely the organic phase and the aqueous phase. The organic phase is formed by adding organic Li to an aqueous solution. + It forms a complex. Li + The complex (and some residual impurity metals) migrate to the organic phase. On the other hand, most of the impurity metals are Li + It remains in the aqueous phase, i.e., the raffinate, after removal. Extracted Li + The organic phase containing the complex is optionally scrubbed to remove any remaining impurities. The optionally scrubbed organic phase is usually stripped with an acid and Li is added to the stripping solution in a high concentration. + It will be recovered. Finally, Li + The organic phase, from which the impurities have been removed, is regenerated and recycled for the extraction process.

[0244] The SX method may use one or more of the following for Li+ extraction: Chelate extractants include, but are not limited to, crown ethers or azacrown ethers, or derivatives thereof. Examples of Li+-selective crown ethers include, but are not limited to, 12-crown-4, 13-crown-4, 14-crown-4, 15-crown-4, benzo-12-crown-4, benzo-14-crown-4, and dibenzo-14-crown-4. Neutral extractants: These include, but are not limited to, ketones, β-diketones, phosphate esters, or phosphine oxides. Examples of neutral extractants include, but are not limited to, methyl isobutyl ketone (MIBK), 2,6-dimethyl-4-heptanone (DIBK), acetophenone (AP), 2-tenoyltrifluoroacetone (TTA), 1-phenyldecane-1,3-dione (LIX 54), 1,3-diphenyl-1,3-propanedione (HDBM), benzoyltrifluoroacetone (BFA), 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP), benzoyl-1,1,1-trifluoroacetone (HBTA), tri-n-butyl phosphate (TBP), triphenylphosphine oxide (TPPO), tri-n-octylphosphine oxide (TOPO), and trialkylphosphine oxide (Cyanex 923). • Ionizable extractants: These include, but are not limited to, compounds having ionizable functional groups such as carboxylic acids, phosphoric acids, or amines. Examples include, but are not limited to, di-(2-ethylhexyl)phosphate (D2EHPA), mono-2-ethylhexyl ester of 2-ethylhexylphosphonic acid (PC88A), mono-2-ethylhexyl phosphoric acid (MEHPA), and bis-2,4,4-trimethylpentylphosphinate (Cyanex 272). Ionic liquids (ILs): ILs are organic compounds composed of ions with low melting points, possessing advantages such as high thermal stability, selectivity, and separation efficiency, while also exhibiting low volatility. Examples, without limitation, include 1-alkyl-3-methylimidazolium-based ionic liquids, such as 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]), and tetrabutylammonium bis(2-ethylhexyl) phosphinate ([N 4444 [BEHP]), tetrabutylammonium bis(2-ethylhexyl) phosphate ([N 4444 [DEHP]), Tetraoctylammonium bis(2-ethylhexyl) phosphate ([N 8888 [DEHP]), tetrabutylammonium mono-2-ethylhexyl (2-ethylhexyl) phosphate ([N 4444 [EHPMEH]), tetrabutylammonium 2-ethylhexyl hydrogen-2-ethylhexylphosphonate ([N 4444 [EHEHP]), tetrabutylammonium diisooctylphosphinate ([N 4444 [DICP]), tetrabutylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ([P 4444 [BTMPP]), trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide ([P 66614 [Tf2N]), N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide ([N 1114 [Tf2N]), 1-butylpyridinium bis(trifluoromethylsulfonyl)imide ([BPy][TF2N]), 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide ([PP 14 [TF2N]), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([P 14 [TF2N]) is one example.

[0245] The SX method may use a multi-component system including an extractant, co-extractant, diluent, or a combination thereof. Examples of extractants include the chelating extractants, neutral extractants, and / or ionizable extractants described herein. The co-extractant may be one or more extractants and / or inorganic compounds such as FeCl3 (but not limited to these) described herein. Non-limiting examples of diluents include aliphatic solvents such as kerosene, aromatic solvents such as xylene, and ionic liquids. Non-limiting examples of multi-component systems include HBTA-TOPO, TTA-TOPO in kerosene, TTA-1,10-phenanthroline in chlorobenzene, TTA-TOPO in m-xylene / MIBK / n-hexane / benzene / chloroform, N,N-bis(2-ethylhexyl)-3-oxobutanamide (NB2EHOTA)-tri-n-butyl phosphate (TBP)-FeCl3, dioctyl phthalate (DOP) / tributyl acetyl citrate (ATBC) / tri-n-butyl citrate (TBC)-TBP-FeCl3, TBP / MIBK-FeCl3-kerosene, TBP-FeCl3-kerosene, TBP-MIBK-FeCl3, and LIX 54-Cyanex 923.

[0246] Figure 18 shows an exemplary embodiment of the use of a membrane electrolytic cell in a lithium production process for selectively removing Li from a Li source containing a lithium-containing solution using solvent extraction. The solvent extraction step generates a lithium-supported solvent, which may optionally be scrubbed to remove additional impurities. The lithium-supported solvent is then treated with a stripping solution to generate a high-concentration lithium-containing salt solution (e.g., LiCl or Li2SO4) and regenerate the solvent. This high-concentration lithium-containing salt solution is supplied to a membrane electrolytic cell, simultaneously generating LiOH and an acid (e.g., HCl or H2SO4). The acid generated from the membrane electrolytic cell is used as a stripping solution to remove Li (e.g., as LiCl or Li2SO4) from the solvent, allowing for solvent regeneration in the SX step. Furthermore, a portion of the LiOH generated from the membrane electrolytic cell may optionally be supplied to a step prior to the SX step to precipitate and remove calcium and / or magnesium from the lithium-containing solution. An exemplary step of this process is as follows: Step 1: Treat the lithium-containing solution with a solvent to extract Li from the lithium-containing solution and form a Li-supported solvent. Step 2: The optionally scrubbed Li-supported solvent is stripped with a stripping solution (e.g., acid) to produce a high-concentration lithium salt-containing solution and regenerate the solvent. Step 3: The high-concentration lithium salt-containing solution is treated in an electrochemical cell to produce lithium hydroxide and acid. Step 4: The lithium hydroxide is either sold to the market or removed from the process, and the acid is supplied to Step 2 to be used as a stripping solution.

[0247] In all embodiments of the lithium recovery process using membrane electrolytic cells with GDE described herein, the role of the GDE is essentially the same across applications, and it is used to recover OH from a humidified oxygen / air gas stream. -The process involves generating ions. Regardless of the type of salt used as the feed brine (LiCl, Li2SO4, Li3PO4, LiNO3, LiI, NaCl, Na2SO4, Na3PO4, NaNO3, NaI, KCl, K2SO4, K3PO4, KNO3, or KI), the cathode catalyst on the GDE always performs the same role. [Examples]

[0248] [Example 1] The GDE relating to this disclosure is a GDL that does not include MPL, and is made from Teflon-coated Avcarb. TM The preparation was done using MGL370 carbon paper. The catalyst ink was Vulcan XC-72 supported 60% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 1.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0249] [Example 2] The GDE relating to this disclosure is a GDL that does not include MPL, and is made from Teflon-coated Avcarb. TM Prepared using MGL370 carbon paper. Catalyst inks used: Pt black, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 2 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0250] [Example 3] The GDE relating to this disclosure is a GDL that does not include MPL, and is Teflon-coated Toray TM The solution was prepared using TGP-H-120 carbon paper. The catalyst ink consisted of Vulcan XC-72 supported 60% platinum and Fumion. TM FAA-3 ionomer and Ultraflon TMThe catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 1.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0251] [Example 4] The GDE relating to this disclosure is a GDL that does not include MPL, and is Teflon-coated Zoltek TM Prepared using Panex PW03 carbon cloth. The catalyst ink was Vulcan XC-72 supported 80% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 2 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0252] [Example 5] The GDE relating to this disclosure is a GDL that does not include MPL, and is made from Teflon-coated Avcarb. TM The preparation was done using MGL370 carbon paper. The catalyst ink was Vulcan XC-72 supported 40% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 0.4 mg / cm³. 2 It was applied to the carbon in this manner.

[0253] [Example 6] The GDE relating to this disclosure is a GDL that does not include MPL, and is made from Teflon-coated Avcarb. TM The preparation was done using MGL190 carbon paper. The catalyst ink was Vulcan XC-72 supported 40% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 0.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0254] [Example 7] The GDE relating to this disclosure is a GDL that does not contain MPL, and is made of Teflon-coated Sigracet. TM The preparation was done using 25BA carbon paper. The catalyst ink consisted of 40% platinum supported on Vulcan XC-72 and Ionomr TM The catalyst ink was prepared by mixing AP1. The catalyst ink had a total catalyst load of 0.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0255] [Example 8] The GDE relating to this disclosure is a GDL that does not contain MPL, and is made of Teflon-coated Sigracet. TM The preparation was done using 25BA carbon paper. The catalyst ink consisted of 20% platinum supported on Vulcan XC-72 and Ionomr TM The catalyst ink was prepared by mixing AP1. The catalyst ink had a total catalyst load of 0.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0256] [Example 9] The GDE relating to this disclosure is a GDL that does not include MPL, and is made from Teflon-coated Avcarb. TM The preparation was done using MGL370 carbon paper. The catalyst ink was Vulcan XC-72 supported 60% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 2.5 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0257] [Example 10] The GDE relating to this disclosure is a GDL that does not include an MPL, and is Avcarb TM The preparation was done using MGL370 carbon paper. The catalyst ink was Vulcan XC-72 supported 40% platinum, Fumion TM FAA-3 ionomer and Ultraflon TMThe catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink had a total catalyst load of 0.4 mg / cm³. 2 It was applied to the carbon paper in this manner.

[0258] [Example 11] The GDE relating to this disclosure is a GDL including the MPL, named Freudenberg. TM The catalyst was prepared using H23C2 carbon paper. A 30 wt% Pt / C catalyst coating was applied, with a total catalyst load of 1 mg / cm³. 2 It was formed on the GDL in this manner.

[0259] [Example 12] The GDE relating to this disclosure is a GDL that does not include MPL, and is Teflon-coated Zoltek TM Prepared using Panex PW03 carbon cloth. The catalyst ink was Vulcan XC-72 supported 60% platinum, Fumion TM FAA-3 ionomer and Ultraflon TM The catalyst ink was prepared by mixing MP-25 PTFE powder. The catalyst ink was prepared by loading a total catalyst amount of 1.5 mg / cm² onto one side of a carbon cloth. 2 Apply to the surface and load a total catalyst amount of 0.5 mg / cm² onto the opposite side. 2 It was applied with [a specific method].

[0260] [Example 13] The GDE relating to this disclosure is a GDL that does not include an MPL, and is named Sigracet TM Prepared using 25BA carbon paper. The catalyst ink consisted of Vulcan XC-72 supported 60% platinum and Fumion TM The catalyst ink was prepared by mixing with FAA-3 ionomer. The catalyst ink had a total catalyst load of 0.4 mg / cm³. 2 The material was then coated onto carbon paper in the following manner. Subsequently, a Teflon dispersion was applied to the catalyst layer at a load of 50%.

[0261] [Example 14] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of 60% silver supported on Vulcan XC-72 and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 3 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0262] [Example 15] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of 60% platinum supported on Vulcan XC-72 and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 1 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0263] [Example 16] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of 60% platinum supported on Vulcan XC-72 and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 2 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0264] [Example 17] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of Vulcan XC-72 supported 40% PtNi (platinum:nickel = 3:1) and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 1 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0265] [Example 18] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of Vulcan XC-72 supported 40% Ni and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 2 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0266] [Example 19] The GDE relating to this disclosure was prepared as a GDL containing MPL using Teflon-coated carbon cloth. The catalyst ink consisted of Vulcan XC-72 supported 40% PtNi (platinum:nickel = 1:1) and Ionomr TM The catalyst ink was prepared by mixing AP3 ionomer. The catalyst ink had a total catalyst load of 1 mg / cm³. 2 It was applied to the carbon cloth in this manner.

[0267] [Example 20] The GDEs of Examples 1 to 19 were prepared and tested as oxygen depolarization cathodes for producing base products (e.g., LiOH) from salt-containing solutions (e.g., LiCl or Li2SO4) in the multi-compartment membrane electrolytic cell described herein. When a voltage was applied to the GDEs of Examples 1 to 19, a current was obtained.

[0268] [Example 21] The film-coated GDE relating to this disclosure is composed of Ionomr in a solvent. TM The coating mixture was prepared by mixing anion-exchange ionomers. The coating mixture contained GDE (for example, GDL containing MPL) and Teflon-coated carbon cloth, with a total catalyst load of 1 mg / cm³ on the carbon cloth. 2 The Pt catalyst ink was then applied to the GDE (Ground Deposition) using the doctor blade method. Subsequently, the coating mixture was cured to form a film-coated GDE. Specifically, three types of film-coated GDEs were prepared with film thicknesses of (i) 30 μm, (ii) 40 μm, and (iii) 60 μm.

[0269] The three types of membrane-coated GDEs described above were tested as oxygen depolarization cathodes for producing base products (e.g., LiOH) from salt-containing solutions (e.g., LiCl or Li2SO4) in the multi-compartment membrane electrolytic cell described herein. When a voltage was applied to each of the three membrane-coated GDEs, a current was obtained. It was observed that thinner coatings exhibited better performance with respect to the voltage requirements for a given current density. Furthermore, it was observed that the membrane-coated GDEs exhibited better performance than the control GDEs hot-pressed onto an anion-exchange membrane.

[0270] [Example 22] The MEA having a textured film according to this disclosure includes (i) Ionomr TM The film was prepared by (ii) pressing an anion exchange membrane (AEM) together with a pattern template for a predetermined time under heating and pressure to form a textured film, and (ii) placing the textured AEM on a GDE to form a MEA having a textured film.

[0271] The MEA having the textured film described above was tested as an oxygen depolarization cathode for producing a base product (e.g., LiOH) from a salt-containing solution (e.g., LiCl or Li2SO4) in a multi-compartment membrane electrolytic cell described herein. When a voltage was applied to the MEA, a current was obtained. It was observed that the MEA with the textured film exhibited superior performance compared to the MEA with the unprocessed film with respect to the voltage requirements for a given current density.

[0272] [Example 23] The GDE having MPL according to this disclosure was prepared by coating a GDL with an MPL formulation containing equal amounts by weight of Teflon and carbon powder in a solvent. The MPL coating was applied to the GDL and then dried before the catalyst layer was applied. Multiple GDEs were prepared, and the MPL formulations were mixed by different methods (e.g., stirring, sonication, or homogenization).

[0273] The GDE having the above-described MPL was tested as an oxygen depolarizing cathode for producing a base product (e.g., LiOH) from a salt-containing solution (e.g., LiCl or Li2SO2) in a multi-compartment membrane electrolytic cell described herein. When a voltage was applied to the GDE having the MPL, a current was obtained. It was observed that the mixing method of the MPL formulation affected its viscosity. Furthermore, the voltage requirements for a particular current density differed depending on the mixing method. However, regardless of the mixing method, the GDE having the MPL generally showed superior performance compared to commercially available GDEs.

[0274] Various non-limiting embodiments of the present invention are summarized below.

[0275] [Aspect 1] A gas diffusion electrode for use in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer.

[0276] [Aspect 2] The gas diffusion electrode according to embodiment 1, wherein the catalyst layer is disposed on the surface of the gas diffusion layer.

[0277] [Aspect 3] The gas diffusion electrode according to embodiment 1, further comprising a microporous layer disposed on the surface of the gas diffusion layer, wherein the catalyst layer is disposed on the surface of the microporous layer opposite to the gas diffusion layer.

[0278] [Aspect 4] The gas diffusion electrode according to embodiment 3, wherein the microporous layer comprises carbon black and a hydrophobic polymer.

[0279] [Aspect 5] The gas diffusion electrode according to embodiment 4, wherein the microporous layer comprises 50% to 95% by weight of carbon black and 5% to 50% by weight of a hydrophobic polymer.

[0280] [Aspect 6] The gas diffusion electrode according to any one of embodiments 1 to 5, wherein the gas diffusion layer includes carbon fiber paper, carbon cloth, carbon felt, carbon foam, metal mesh, metal foam, or any combination thereof.

[0281] [Aspect 7] A gas diffusion electrode according to any one of embodiments 1 to 6, wherein the gas diffusion layer is modified with a hydrophobic polymer.

[0282] [Aspect 8] The gas diffusion electrode according to embodiment 7, wherein the hydrophobic polymer is polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene, perfluoropolyether, polydimethylsiloxane, or any combination thereof.

[0283] [Aspect 9] The gas diffusion electrode according to embodiment 7 or 8, wherein the gas diffusion layer contains 0.01% to 50% by weight of a hydrophobic polymer.

[0284] [Aspect 10] The gas diffusion electrode according to any one of embodiments 1 to 9, wherein the thickness of the gas diffusion layer is 50 μm to 1000 μm.

[0285] [Aspect 11] A gas diffusion electrode according to any one of embodiments 1 to 10, wherein the porosity of the gas diffusion layer is 50% to 95%.

[0286] [Aspect 12] The catalyst layer comprises a catalyst and an ionomer, wherein the gas diffusion electrode is according to any one of embodiments 1 to 11.

[0287] [Aspect 13] The gas diffusion electrode according to embodiment 12, wherein the ionomer:catalyst ratio in the catalyst layer is 1:1 to 1:20.

[0288] [Aspect 14] The catalyst layer further comprises a binder, wherein the gas diffusion electrode is according to embodiment 12 or 13.

[0289] [Aspect 15] The gas diffusion electrode according to embodiment 14, wherein the binder is PTFE.

[0290] [Aspect 16] The catalyst layer comprises 0.01% to 40% by weight of the binder, wherein the gas diffusion electrode is according to embodiment 14 or 15.

[0291] [Aspect 17] The gas diffusion electrode according to any one of embodiments 12 to 16, wherein the catalyst is a metal, a nonmetal, or a combination thereof.

[0292] [Aspect 18] The gas diffusion electrode according to embodiment 17, wherein the metal is a transition metal, a post-transition metal, a metalloid, a combination thereof, or an alloy thereof.

[0293] [Aspect 19] The gas diffusion electrode according to embodiment 17, wherein the nonmetal is carbon, a conductive polymer, or a combination thereof.

[0294] [Aspect 20] The gas diffusion electrode according to any one of embodiments 12 to 19, wherein the ionomer is an anion exchange ionomer.

[0295] [Aspect 21] The aforementioned anion-exchange ionomer is Fumion TM FAA-3, Ionomr TM , Sustainion(R), Orion, Pension TM A gas diffusion electrode according to embodiment 20, which is either a PiperION anion exchange ionomer or a PiperION anion exchange ionomer.

[0296] [Aspect 22] The catalyst layer comprises 5% to 45% by weight of the ionomer, wherein the gas diffusion electrode is according to any one of embodiments 12 to 21.

[0297] [Aspect 23] A gas diffusion electrode according to any one of embodiments 1 to 22, wherein the thickness of the catalyst layer is 1 μm to 100 μm.

[0298] [Aspect 24] A gas diffusion electrode according to any one of embodiments 1 to 23, wherein the porosity of the catalyst layer is 30% to 75%.

[0299] [Pattern 25] A gas diffusion electrode according to any one of embodiments 1 to 24, which is any of the GDE embodiments 1 to 896 and 1a to 896a described herein.

[0300] [Aspect 26] A gas diffusion electrode according to any one of embodiments 1 to 25, further comprising an embossed and / or debossed pattern on at least one surface.

[0301] [Aspect 27] A gas diffusion electrode according to any one of embodiments 1 to 25, further comprising an anion exchange membrane disposed on the surface of the catalyst layer, wherein the anion exchange membrane is configured to exchange ions from the catalyst layer to the surface opposite the anion exchange membrane.

[0302] [Aspect 28] The gas diffusion electrode according to embodiment 27, wherein the anion exchange membrane comprises a polymer having at least one positively charged cationic group bonded to at least a portion of the polymer main chain.

[0303] [Aspect 29] The gas diffusion electrode according to embodiment 28, wherein the polymer comprises polyalkylene, polyfluorene, poly(arylene ether), polysulfone, poly(arylene ethersulfone), polyetherketone, polyetherimide, poly(etheroxadiazole), poly(phenylene oxide), poly(vinylbenzyl), polyphenylene, perfluoroelastomer, polybenzimidazole, polystyrene, or polyphosphazene.

[0304] [Aspect 30] The gas diffusion electrode according to embodiment 28 or 29, wherein the positively charged cationic group is a primary, secondary, tertiary, or quaternary ammonium, a heterocyclic cation, guanidinium, phosphonium, sulfonium, or a metal cation.

[0305] [Aspect 31] The anion exchange membrane is Fumasep TM Neosepta TM Orion TM Xergy Xion Pension TM PiperION TM Ralex TM Sustainment TM , or Ionomr TM A gas diffusion electrode according to any one of embodiments 27 to 30, which is an anion exchange membrane.

[0306] [Aspect 32] A gas diffusion electrode according to any one of embodiments 27 to 31, further comprising an embossed and / or debossed pattern on at least one surface.

[0307] [Aspect 33] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode comprising a gas diffusion electrode according to any one of embodiments 1 to 26, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; a cation exchange membrane interposed between the anode compartment and the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the anode to the opposite surface of the cation exchange membrane; an inlet for supplying the salt-containing solution to the anode compartment; a gas inlet for introducing a gas containing O2 into contact with the gas diffusion electrode; and at least one outlet from which the products of the salt solution are removed from inside the membrane electrolytic cell.

[0308] [Aspect 34] A membrane electrolytic cell for processing a salt-containing solution, comprising an anode compartment, a cathode compartment, a base accumulation compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, and a gas diffusion electrode according to any one of embodiments 1 to 26, comprising a cathode disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and an anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, wherein ions received from the catalyst layer of the gas diffusion electrode are transferred to the opposite side of the anion exchange membrane. A membrane electrolytic cell comprising: an anion exchange membrane configured to exchange ions to the base storage compartment via its surface; a cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode to the base storage compartment via the opposite surface of the cation exchange membrane; an inlet for supplying the salt-containing solution to the anode compartment; a gas inlet located within the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0309] [Aspect 35] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a gas diffusion electrode according to any one of embodiments 1 to 26, wherein the cathode is disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; and a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, wherein ions received from the catalyst layer of the gas diffusion electrode are transferred via the surface opposite to the first anion exchange membrane. A membrane electrolytic cell comprising: a first anion exchange membrane configured to exchange ions to the base accumulation compartment; a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the second anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0310] [Aspect 36] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a gas diffusion electrode according to any one of embodiments 1 to 26, comprising: a cathode disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; a first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base accumulation compartment via the opposite surface of the first anion exchange membrane; and A membrane electrolytic cell comprising: a first cation exchange membrane interposed between a salt depletion compartment and a base accumulation compartment, configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; a second anion exchange membrane interposed between the salt depletion compartment and an acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the second anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and an anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0311] [Aspect 37] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 33, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and into the cathode compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - A method comprising the combination of an ion with the positive salt ion to produce the base product, and the removal of the base product from the cathode compartment.

[0312] [Aspect 38] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 34, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and into the base storage compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the anion exchange membrane and move into the base accumulation compartment via the surface opposite to the anion exchange membrane, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0313] [Aspect 39] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 35, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the surface opposite to the first anion exchange membrane, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0314] [Aspect 40] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 36, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and into the base accumulation compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the surface opposite to the first anion exchange membrane, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0315] [Aspect 41] A gas diffusion electrode used in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst coating film including a catalyst layer disposed on the surface of the film.

[0316] [Aspect 42] The gas diffusion electrode according to embodiment 41, wherein the aforementioned membrane is an anion exchange membrane.

[0317] [Aspect 43] The gas diffusion electrode according to embodiment 42, wherein the anion exchange membrane comprises a polymer having at least one positively charged cationic group bonded to at least a portion of the polymer main chain.

[0318] [Aspect 44] The gas diffusion electrode according to embodiment 43, wherein the polymer is polyalkylene, polyfluorene, poly(arylene ether), polysulfone, poly(arylene ethersulfone), polyetherketone, polyetherimide, poly(etheroxadiazole), poly(phenylene oxide), poly(vinylbenzyl), polyphenylene, perfluoroelastomer, polybenzimidazole, polystyrene, or polyphosphazene.

[0319] [Aspect 45] The gas diffusion electrode according to embodiment 43 or 44, wherein the positively charged cationic group is a primary, secondary, tertiary, or quaternary ammonium, a heterocyclic cation, guanidinium, phosphonium, sulfonium, or a metal cation.

[0320] [Aspect 46] The anion exchange membrane is Fumasep TM Neosepta TM Orion TM Xergy Xion Pension TM PiperION TM Ralex TM Sustainment TM , or Ionomr TM A gas diffusion electrode according to any one of embodiments 42245, which is an anion exchange membrane.

[0321] [Aspect 47] The gas diffusion electrode according to any one of embodiments 41246, wherein the gas diffusion layer is in contact with the catalyst layer of the catalyst coating film.

[0322] [Aspect 48] A gas diffusion electrode according to any one of the embodiments of 41246, further comprising a microporous layer disposed on the surface of the gas diffusion layer, wherein the microporous layer is in contact with the catalyst layer of the catalyst coating film.

[0323] [Aspect 49] The gas diffusion electrode according to embodiment 48, wherein the microporous layer comprises carbon black and a hydrophobic polymer.

[0324] [Aspect 50] The gas diffusion electrode according to embodiment 48 or 49, wherein the microporous layer comprises 50% to 95% by weight of carbon black and 5% to 50% by weight of a hydrophobic polymer.

[0325] [Aspect 51] The gas diffusion electrode according to any one of embodiments 41 to 50, wherein the gas diffusion layer includes carbon fiber paper, carbon cloth, carbon felt, carbon foam, metal mesh, metal foam, or any combination thereof.

[0326] [Aspect 52] A gas diffusion electrode according to any one of embodiments 41 to 51, wherein the gas diffusion layer is modified with a hydrophobic polymer.

[0327] [Aspect 53] The gas diffusion electrode according to embodiment 52, wherein the hydrophobic polymer is polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene, perfluoropolyether, polydimethylsiloxane, or any combination thereof.

[0328] [Aspect 54] The gas diffusion electrode according to embodiment 52 or 53, wherein the gas diffusion layer contains 0.01% to 50% by weight of a hydrophobic polymer.

[0329] [Aspect 55] The gas diffusion electrode according to any one of embodiments 41 to 54, wherein the thickness of the gas diffusion layer is 50 μm to 1000 μm.

[0330] [Aspect 56] A gas diffusion electrode according to any one of embodiments 41 to 55, wherein the porosity of the gas diffusion layer is 50% to 95%.

[0331] [Aspect 57] The catalyst layer comprises a catalyst and an ionomer, as described in any one of embodiments 41 to 56, for the gas diffusion electrode.

[0332] [Aspect 58] The gas diffusion electrode according to embodiment 57, wherein the ionomer:catalyst ratio in the catalyst layer is 1:1 to 1:20.

[0333] [Aspect 59] The catalyst layer further comprises a binder, as described in embodiment 57 or 58, for the gas diffusion electrode.

[0334] [Aspect 60] The gas diffusion electrode according to embodiment 59, wherein the binder is PTFE.

[0335] [Aspect 61] The catalyst layer comprises 0.01% to 40% by weight of the binder, wherein the gas diffusion electrode is according to embodiment 59 or 60.

[0336] [Aspect 62] The gas diffusion electrode according to any one of embodiments 57 to 61, wherein the catalyst is a metal, a nonmetal, or a combination thereof.

[0337] [Aspect 63] The gas diffusion electrode according to embodiment 62, wherein the metal is a transition metal, a post-transition metal, a metalloid, a combination thereof, or an alloy thereof.

[0338] [Aspect 64] The gas diffusion electrode according to embodiment 62, wherein the nonmetal is carbon, a conductive polymer, or a combination thereof.

[0339] [Aspect 65] The gas diffusion electrode according to any one of embodiments 57 to 64, wherein the ionomer is an anion exchange ionomer.

[0340] [Aspect 66] The aforementioned anion-exchange ionomer is Fumion TM FAA-3, Ionomr TM , Sustainion(R), Orion, Pension TM A gas diffusion electrode according to embodiment 65, which is either a PiperION anion exchange ionomer or a PiperION anion exchange ionomer.

[0341] [Aspect 67] The catalyst layer comprises 5% to 45% by weight of the ionomer, wherein the gas diffusion electrode is according to any one of embodiments 57 to 66.

[0342] [Pattern 68] A gas diffusion electrode according to any one of embodiments 41 to 67, wherein the thickness of the catalyst layer is 1 μm to 100 μm.

[0343] [Aspect 69] A gas diffusion electrode according to any one of embodiments 41 to 68, wherein the porosity of the catalyst layer is 30% to 75%.

[0344] [Aspect 70] A gas diffusion electrode according to any one of embodiments 41 to 69, which is any of the GDE embodiments 1 to 896 and 1a to 896a described herein.

[0345] [Aspect 71] A gas diffusion electrode according to any one of embodiments 41 to 70, further comprising an embossed and / or debossed pattern on at least one surface.

[0346] [Aspect 72] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; a base accumulation compartment interposed between the cathode compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode comprising a gas diffusion electrode according to any one of embodiments 41 to 71, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; a cation exchange membrane interposed between the anode compartment and the base accumulation compartment, configured to exchange ions received from the anode to the base accumulation compartment via the opposite surface of the cation exchange membrane; an inlet for supplying the salt-containing solution to the anode compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0347] [Aspect 73] A membrane electrolytic cell for processing a salt-containing solution, comprising an anode compartment, a cathode compartment, a base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, and a gas diffusion electrode according to any one of embodiments 41 to 71, wherein the cathode is disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and interposed between the salt depletion compartment and the base accumulation compartment A membrane electrolytic cell comprising: a cation exchange membrane configured to exchange ions received from the salt depletion compartment to the base accumulation compartment via the opposite surface of the cation exchange membrane; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0348] [Aspect 74] A membrane electrolytic cell for processing a salt-containing solution, comprising an anode compartment, a cathode compartment, a base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, and a cathode comprising a gas diffusion electrode according to any one of embodiments 41 to 71, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, wherein ions received from the salt depletion compartment A membrane electrolytic cell comprising: a first cation exchange membrane configured to exchange ions to the base accumulation compartment via the opposite surface of the cation exchange membrane; an anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, configured to exchange ions received from the salt depletion compartment to the acid accumulation compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid accumulation compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0349] [Aspect 75] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 72, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and into the base storage compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0350] [Aspect 76] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 73, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions move through the catalyst coating exchange membrane into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0351] [Aspect 77] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 74, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and into the base accumulation compartment via the opposite surface of the first cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the catalyst coating film and move into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base storage compartment to produce the base product; and the base product being removed from the base storage compartment.

[0352] [Aspect 78] A gas diffusion electrode for use in a membrane electrolytic cell, comprising a gas diffusion layer for diffusing an oxygen-containing gas, and a catalyst layer disposed on the gas diffusion layer, wherein the catalyst layer has a thickness optimized such that liquid reactants diffusing across the catalyst layer are consumed substantially or completely before reaching the gas diffusion layer.

[0353] [Aspect 79] The gas diffusion electrode according to embodiment 78, wherein the gas diffusion layer includes carbon fiber paper, carbon cloth, carbon felt, carbon foam, metal mesh, metal foam, or any combination thereof.

[0354] [Aspect 80] The gas diffusion electrode according to embodiment 78 or 79, wherein the gas diffusion layer is modified with a hydrophobic polymer.

[0355] [Aspect 81] The gas diffusion electrode according to embodiment 80, wherein the hydrophobic polymer is polytetrafluoroethylene, polyvinylidene fluoride, fluorinated ethylene propylene, perfluoropolyether, polydimethylsiloxane, or any combination thereof.

[0356] [Aspect 82] The gas diffusion electrode according to embodiment 80 or 81, wherein the gas diffusion layer contains 0.01% to 50% by weight of a hydrophobic polymer.

[0357] [Aspect 83] The gas diffusion electrode according to any one of embodiments 78 to 82, wherein the thickness of the gas diffusion layer is 50 μm to 1000 μm.

[0358] [Aspect 84] A gas diffusion electrode according to any one of embodiments 78 to 83, wherein the porosity of the gas diffusion layer is 50% to 95%.

[0359] [Aspect 85] The catalyst layer comprises a catalyst and an ionomer, as described in any one of embodiments 78 to 84, for the gas diffusion electrode.

[0360] [Aspect 86] The gas diffusion electrode according to embodiment 85, wherein the ionomer:catalyst ratio in the catalyst layer is 1:1 to 1:20.

[0361] [Aspect 87] The catalyst layer further comprises a binder, the gas diffusion electrode according to embodiment 85 or 86.

[0362] [Pattern 88] The gas diffusion electrode according to embodiment 87, wherein the binder is PTFE.

[0363] [Aspect 89] The catalyst layer comprises 0.01% to 40% by weight of the binder, wherein the gas diffusion electrode is according to embodiment 87 or 88.

[0364] [Aspect 90] The gas diffusion electrode according to any one of embodiments 85 to 89, wherein the catalyst is a metal, a nonmetal, or a combination thereof.

[0365] [Aspect 91] The gas diffusion electrode according to embodiment 90, wherein the metal is a transition metal, a post-transition metal, a metalloid, a combination thereof, or an alloy thereof.

[0366] [Aspect 92] The gas diffusion electrode according to embodiment 90, wherein the nonmetal is carbon, a conductive polymer, or a combination thereof.

[0367] [Aspect 93] The gas diffusion electrode according to any one of embodiments 85 to 92, wherein the ionomer is an anion exchange ionomer.

[0368] [Aspect 94] The aforementioned anion-exchange ionomer is Fumion TM FAA-3, Ionomr TM , Sustainion(R), Orion, Pension TM A gas diffusion electrode according to embodiment 93, which is either a PiperION anion exchange ionomer or a PiperION anion exchange ionomer.

[0369] [Aspect 95] The catalyst layer comprises 5% to 45% by weight of the ionomer, wherein the gas diffusion electrode is according to any one of embodiments 85 to 94.

[0370] [Aspect 96] A gas diffusion electrode according to any one of embodiments 78 to 95, wherein the thickness of the catalyst layer is 1 μm to 100 μm.

[0371] [Aspect 97] A gas diffusion electrode according to any one of embodiments 78 to 96, wherein the porosity of the catalyst layer is 30% to 75%.

[0372] [Aspect 98] A gas diffusion electrode according to any one of embodiments 78 to 97, which is any of GDE embodiments 1 to 896 and 1a to 896a described herein.

[0373] [Aspect 99] A gas diffusion electrode according to any one of embodiments 78 to 98, further comprising an embossed and / or debossed pattern on at least one surface.

[0374] [Aspect 100] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; a base accumulation compartment that, together with the cathode compartment, forms a single compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode comprising a gas diffusion electrode according to any one of embodiments 78 to 99, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; a cation exchange membrane interposed between the anode compartment and the base accumulation compartment, configured to exchange ions received from the anode to the base accumulation compartment via the opposite surface of the cation exchange membrane; an inlet for supplying the salt-containing solution to the anode compartment; a gas inlet located within the cathode compartment, through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from inside the membrane electrolytic cell.

[0375] [Aspect 101] A membrane electrolytic cell for processing a salt-containing solution, comprising an anode compartment, a cathode compartment, a base accumulation compartment which together with the cathode compartment forms a single compartment, a salt depletion compartment interposed between the cathode compartment and the anode compartment, an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment, and a gas diffusion electrode according to any one of embodiments 78 to 99, comprising a cathode disposed to extend inside the membrane electrolytic cell and located within the cathode compartment, and a cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, which receives ions from the salt depletion compartment. A membrane electrolytic cell comprising: a cation exchange membrane configured to exchange ions to the base accumulation compartment via the opposite surface of the cation exchange membrane; an anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment to the anode compartment via the opposite surface of the anion exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located within the cathode compartment into which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0376] [Aspect 102] A membrane electrolytic cell for processing a salt-containing solution, comprising: an anode compartment; a cathode compartment; a base accumulation compartment that, together with the cathode compartment, forms a single compartment; a salt depletion compartment and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment; an anode disposed to extend inside the membrane electrolytic cell and located within the anode compartment; a cathode according to any one of embodiments 78 to 99, disposed to extend inside the membrane electrolytic cell and located within the cathode compartment; and a first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, which exchanges ions received from the salt depletion compartment. A membrane electrolytic cell comprising: a first cation exchange membrane configured to exchange ions to the base storage compartment via the opposite surface of the membrane; an anion exchange membrane interposed between the salt depletion compartment and the acid storage compartment, configured to exchange ions received from the salt depletion compartment to the acid storage compartment via the opposite surface of the anion exchange membrane; a second cation exchange membrane interposed between the acid storage compartment and the anode compartment, configured to exchange ions received from the anode compartment to the acid storage compartment via the opposite surface of the second cation exchange membrane; an inlet for supplying the salt-containing solution to the salt depletion compartment; a gas inlet located in the cathode compartment through which a gas containing O2 is introduced so as to come into contact with the gas diffusion electrode; and at least one outlet from which the product is removed from the inside of the membrane electrolytic cell.

[0377] [Aspect 103] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 100, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to the anode compartment, the positive salt ions move through the cation exchange membrane and into the base storage compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base accumulation compartment to produce the base product; and the base product being removed from the membrane electrolytic cell.

[0378] [Aspect 104] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 101, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the opposite surface of the cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base accumulation compartment to produce the base product; and the base product being removed from the membrane electrolytic cell.

[0379] [Aspect 105] A method for producing a base product, comprising the steps of receiving a salt-containing solution containing positive and negative salt ions and a gas containing O2 in a membrane electrolytic cell according to embodiment 102, and removing the base product from the membrane electrolytic cell, wherein in carrying out the method, the salt-containing solution is supplied to a salt-depletion compartment, the positive salt ions move through the first cation exchange membrane and into the base accumulation compartment via the opposite surface of the first cation exchange membrane, and the gas containing O2 is reduced at the cathode to OH - Generates the OH - The ions pass through the catalyst layer and move into the base accumulation compartment, and the OH - A method comprising: an ion combining with the positive salt ion in the base accumulation compartment to produce the base product; and the base product being removed from the membrane electrolytic cell.

[0380] [Aspect 106] A gas diffusion electrode used in a membrane electrolytic cell, comprising: a first gas diffusion layer for diffusing an oxygen-containing gas; a catalyst layer disposed on the surface of the first gas diffusion layer; a second gas diffusion layer in contact with the surface of the catalyst layer opposite to the first gas diffusion layer; and an ionomer layer disposed on the surface of an anion exchange membrane and in contact with the surface of the second gas diffusion layer opposite to the catalyst layer.

[0381] [Aspect 107] The gas diffusion electrode according to embodiment 106, further comprising a microporous layer disposed on the surface of the second gas diffusion layer, wherein the microporous layer is in contact with the surface of the catalyst layer opposite to the first gas diffusion layer.

[0382] [Aspect 108] A method for producing LiOH from a Li source, comprising: (a) contacting the Li source with a solvent to extract lithium from the Li source and obtain a lithium-containing solvent; (b) contacting the lithium-containing solvent with a stripping agent to regenerate the solvent and generate a salt-containing solution containing lithium ions and negative salt ions; (c) receiving the salt-containing solution and a gas containing O2 in a membrane electrolytic cell; and (d) extracting LiOH and / or acid from the membrane electrolytic cell.

[0383] [Aspect 109] The method according to embodiment 108, wherein the salt-containing solution comprises LiCl or Li2SO4.

[0384] [Aspect 110] The method according to embodiment 108, wherein the acid is HCl or H2SO4.

[0385] [Aspect 111] The method according to any one of embodiments 108 to 110, wherein the solvent comprises one or more of a chelating extractant, a neutral extractant, an ionizable extractant, and an ionic liquid.

[0386] [Aspect 112] The method according to any one of embodiments 108 to 110, wherein the solvent comprises a multi-component system including an extractant, a co-extractant, a diluent, or a combination thereof.

[0387] [Aspect 113] The method according to any one of embodiments 108 to 112, further comprising the step of purifying the lithium-supported solvent by exposing it to a scrubbing solution before contacting the lithium-supported solvent with the stripping agent.

[0388] [Aspect 114] A method further comprising the step of supplying a portion of the acid extracted in step (d) to step (b) and using it as the stripping agent.

[0389] [Aspect 115] The method according to any one of embodiments 108 to 114, further comprising the step of precipitating at least one of calcium and magnesium from the lithium source.

[0390] [Aspect 116] The method according to embodiment 115, further comprising the step of supplying a portion of the LiOH removed in step (d) to a step of precipitating at least one of the calcium and magnesium.

[0391] [Aspect 117] A membrane-coated gas diffusion electrode for use in a membrane electrolytic cell, comprising a gas diffusion electrode including a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer, and an anion exchange membrane coated on the gas diffusion electrode.

[0392] [Aspect 118] A method for manufacturing a film-coated gas diffusion electrode, comprising the steps of: preparing a coating mixture by mixing an ionomer in a solvent; applying the coating mixture to a gas diffusion electrode; and curing the mixture to form the film-coated gas diffusion electrode.

[0393] [Aspect 119] The aforementioned ionomer is Fumion TM Ionomer TM Ionomers, Sustainion(R) ionomers, Orion ionomers, Pention TM The method according to embodiment 118, wherein the ionomer is an ionomer or a PiperION ionomer.

[0394] [Aspect 120] The method according to embodiment 118 or 119, wherein the solvent comprises an alcohol.

[0395] [Aspect 121] The method according to any one of embodiments 118 to 120, wherein the ionomer is mixed in the solvent at a concentration of 2 to 15% by weight.

[0396] [Aspect 122] The gas diffusion electrode comprises a gas diffusion layer for diffusing an oxygen-containing gas and a catalyst layer, according to any one of embodiments 118 to 121.

[0397] [Aspect 123] The method according to any one of embodiments 118 to 122, wherein the thickness of the coating mixture is 20 μm to 100 μm.

[0398] [Aspect 124] The method according to any one of embodiments 118 to 123, wherein the curing is performed at a temperature of 50°C to 140°C.

[0399] In this disclosure, all terms expressed in the singular form are construed to include their plural forms. Similarly, all terms expressed in the plural form are construed to include their singular forms. Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as those generally understood by those skilled in the art to which this disclosure relates.

[0400] In this specification, the term "about" means a variation of approximately ±10% from a given value. Such variation should be understood to always be included in any given value provided herein, unless otherwise explicitly stated.

[0401] While compositions and methods are described using terms such as “comprising,” “containing,” or “including” various components or steps, it should be understood that compositions and methods may also “consist essentially of” or “consist of” various components and steps. Furthermore, the indefinite articles “a” and “an” used in the claims are defined herein as meaning one or more of the elements being introduced.

[0402] For the sake of brevity, only specific ranges are explicitly disclosed in this specification. However, any lower limit can be combined with any upper limit to describe an unexpressed range. Similarly, any lower limit can be combined with other lower limits to describe an unexpressed range. Furthermore, any upper limit can be combined with other upper limits to describe an unexpressed range. In addition, where a numerical range with lower and upper limits is disclosed, any numerical values ​​within that range and the ranges they encompass are also specifically disclosed. In particular, any range of values ​​disclosed in this specification (in the form of "approximately a to approximately b," "roughly a to b," or "approximately a to b") is interpreted to include all numerical values ​​and ranges that fall within a broader range of values, even if not explicitly stated. Thus, any point or individual value, combined with other points or individual values, or with other lower or upper limits, can function as a lower or upper limit itself, indicating an unexpressed range.

[0403] Accordingly, this disclosure is well suited to achieving the purposes and benefits described above, as well as the purposes and benefits inherently present herein. The specific embodiments disclosed above are illustrative only, and this disclosure can be modified and implemented in different but equivalent ways that will be apparent to those skilled in the art who benefit from the teachings herein. Although individual embodiments are described, this disclosure covers all combinations of all such embodiments. Furthermore, there is no intention to limit the structural or design details shown herein, except as described in the claims. Also, terms in the claims have their ordinary meanings unless expressly and clearly defined by the patentee. Accordingly, the specific exemplary embodiments disclosed above can be modified or altered, and all such variations are considered to be within the scope and spirit of this disclosure. In the event of any inconsistency between the use of terms in this specification and in any patent or other document that may be referenced herein, the definition consistent with this specification shall prevail.

[0404] Based on this disclosure, numerous modifications of embodiments that will be obvious to those skilled in the art can be envisioned. These obvious modifications will also be included within the scope intended by the supplementary claims.

Claims

1. A gas diffusion electrode used in a membrane electrolytic cell, A gas diffusion layer that diffuses oxygen-containing gas, Catalyst layer and A gas diffusion electrode equipped with a gas diffusion electrode.

2. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 1, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A cation exchange membrane interposed between the anode compartment and the catalyst layer of the gas diffusion electrode, wherein the cation exchange membrane is configured to exchange ions received from the anode to the surface opposite the cation exchange membrane, The inlet where the salt-containing solution is supplied to the anode section, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product of the salt solution is removed from the inside of the membrane electrolytic cell through at least one outlet. A membrane electrolytic cell equipped with the following features.

3. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment interposed between the cathode compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 1, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, An anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode to the base storage compartment via the opposite surface of the anion exchange membrane, A cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode with the base storage compartment via the opposite surface of the cation exchange membrane, The inlet where the salt-containing solution is supplied to the anode section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

4. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 1, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode with the base storage compartment via the surface opposite to the first anion exchange membrane, A cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, A second anion exchange membrane interposed between the salt depletion compartment and the anode compartment, the second anion exchange membrane configured to exchange ions received from the salt depletion compartment with the anode compartment via the opposite surface of the second anion exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

5. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 1, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A first anion exchange membrane disposed on the catalyst layer of the gas diffusion electrode, configured to exchange ions received from the catalyst layer of the gas diffusion electrode with the base storage compartment via the surface opposite to the first anion exchange membrane, A first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, A second anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, the second anion exchange membrane configured to exchange ions received from the salt depletion compartment with the acid accumulation compartment via the opposite surface of the second anion exchange membrane, A second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment with the acid accumulation compartment via the opposite surface of the second cation exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

6. A method for producing a base product, In the membrane electrolytic cell according to claim 2, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the anode section. The positive salt ions move through the cation exchange membrane and into the cathode compartment via the opposite surface of the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ion combines with the positive salt ion to produce the base product, A method for removing the base product from the cathode compartment.

7. A method for producing a base product, In the membrane electrolysis cell according to claim 3, a step of receiving a salt-containing solution containing positive and negative salt ions, and a gas containing O 2 and; The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the anode section. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the anion exchange membrane and move into the base accumulation compartment via the surface opposite to the anion exchange membrane. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

8. A method for producing a base product, In the membrane electrolytic cell according to claim 4, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the opposite surface of the first anion exchange membrane. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

9. A method for producing a base product, In the membrane electrolytic cell according to claim 5, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions pass through the first cation exchange membrane and move into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the first anion exchange membrane and move into the base accumulation compartment via the opposite surface of the first anion exchange membrane. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

10. A gas diffusion electrode used in a membrane electrolytic cell, A gas diffusion layer that diffuses oxygen-containing gas, A catalyst coating film including a catalyst layer arranged on the surface of the film and A gas diffusion electrode equipped with a gas diffusion electrode.

11. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment interposed between the cathode compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 10, wherein the electrode is arranged to extend inside the membrane electrolytic cell and the cathode is located within the cathode compartment, A cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode with the base storage compartment via the opposite surface of the cation exchange membrane, The inlet where the salt-containing solution is supplied to the anode section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

12. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment and a salt depletion compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, and the salt depletion compartment is interposed between the base accumulation compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 10, wherein the electrode is arranged to extend inside the membrane electrolytic cell and the cathode is located within the cathode compartment, A cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, An anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment with the anode compartment via the opposite surface of the anion exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

13. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, A base accumulation compartment, a salt depletion compartment, and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the base accumulation compartment is interposed between the cathode compartment and the salt depletion compartment, the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 10, wherein the electrode is arranged to extend inside the membrane electrolytic cell and the cathode is located within the cathode compartment, A first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, An anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, wherein the anion exchange membrane is configured to exchange ions received from the salt depletion compartment with the acid accumulation compartment via the opposite surface of the anion exchange membrane, A second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment with the acid accumulation compartment via the opposite surface of the second cation exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

14. A method for producing a base product, In the membrane electrolytic cell according to claim 11, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the anode section. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions move through the catalyst coating film into the base accumulation compartment. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

15. A method for producing a base product, In the membrane electrolytic cell according to claim 12, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions move through the catalyst coating exchange membrane into the base accumulation compartment, The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

16. A method for producing a base product, In the membrane electrolytic cell according to claim 13, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions move through the first cation exchange membrane and into the base accumulation compartment via the surface opposite to the first cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions move through the catalyst coating film into the base accumulation compartment. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the base storage compartment.

17. A gas diffusion electrode used in a membrane electrolytic cell, A gas diffusion layer that diffuses oxygen-containing gas, A catalyst layer disposed on the gas diffusion layer and Equipped with, A gas diffusion electrode wherein the catalyst layer has a thickness optimized such that liquid reactants diffusing across the catalyst layer are consumed substantially or completely before reaching the gas diffusion layer.

18. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, Together with the cathode compartment, a base accumulation compartment forms a single compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 17, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A cation exchange membrane interposed between the anode compartment and the base storage compartment, configured to exchange ions received from the anode with the base storage compartment via the opposite surface of the cation exchange membrane, The inlet where the salt-containing solution is supplied to the anode section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

19. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, Together with the cathode compartment, a base accumulation compartment forms a single compartment, A salt-depleted section is interposed between the cathode section and the anode section, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 17, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, An anion exchange membrane interposed between the salt depletion compartment and the anode compartment, configured to exchange ions received from the salt depletion compartment with the anode compartment via the opposite surface of the anion exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

20. A membrane electrolytic cell for processing salt-containing solutions, A scattered section and Cathode section and, Together with the cathode compartment, a base accumulation compartment forms a single compartment, A salt depletion compartment and an acid accumulation compartment interposed between the cathode compartment and the anode compartment, wherein the salt depletion compartment is interposed between the base accumulation compartment and the acid accumulation compartment, and the acid accumulation compartment is interposed between the salt depletion compartment and the anode compartment, An anode is arranged to extend inside the membrane electrolytic cell and is located within the anode compartment, A gas diffusion electrode according to claim 17, comprising a cathode positioned within the cathode compartment and extending inside the membrane electrolytic cell, A first cation exchange membrane interposed between the salt depletion compartment and the base accumulation compartment, configured to exchange ions received from the salt depletion compartment with the base accumulation compartment via the opposite surface of the cation exchange membrane, An anion exchange membrane interposed between the salt depletion compartment and the acid accumulation compartment, wherein the anion exchange membrane is configured to exchange ions received from the salt depletion compartment with the acid accumulation compartment via the opposite surface of the anion exchange membrane, A second cation exchange membrane interposed between the acid accumulation compartment and the anode compartment, configured to exchange ions received from the anode compartment with the acid accumulation compartment via the opposite surface of the second cation exchange membrane, The inlet where the salt-containing solution is supplied to the salt-depleted section, Located within the cathode compartment, O ２ A gas inlet is introduced so that a gas containing the gas comes into contact with the gas diffusion electrode, The product is removed from the inside of the membrane electrolytic cell through at least one outlet and A membrane electrolytic cell equipped with the following features.

21. A method for producing a base product, In the membrane electrolytic cell according to claim 18, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the anode section. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the catalyst layer and move into the base accumulation compartment. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the membrane electrolytic cell.

22. A method for producing a base product, In the membrane electrolytic cell according to claim 19, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions move through the cation exchange membrane and into the base accumulation compartment via the surface opposite to the cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the catalyst layer and move into the base accumulation compartment. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the membrane electrolytic cell.

23. A method for producing a base product, In the membrane electrolytic cell according to claim 20, a salt-containing solution comprising positive salt ions and negative salt ions, and O 2 A step of receiving a gas containing, The step of removing the base product from the membrane electrolytic cell. Includes, In implementing the said method, The salt-containing solution is supplied to the salt-depleted area. The positive salt ions move through the first cation exchange membrane and into the base accumulation compartment via the surface opposite to the first cation exchange membrane. The aforementioned O 2 The gas containing OH is reduced at the cathode. － Generate, The aforementioned OH － The ions pass through the catalyst layer and move into the base accumulation compartment. The aforementioned OH － The ions combine with the positive salt ions in the base accumulation compartment to produce the base product, A method for removing the base product from the membrane electrolytic cell.

24. A gas diffusion electrode used in a membrane electrolytic cell, A first gas diffusion layer that diffuses oxygen-containing gas, A catalyst layer disposed on the surface of the first gas diffusion layer, A second gas diffusion layer in contact with the surface of the catalyst layer opposite to the first gas diffusion layer, An ionomer layer is disposed on the surface of the anion exchange membrane and is in contact with the surface of the second gas diffusion layer on the opposite side of the catalyst layer. A gas diffusion electrode equipped with a gas diffusion electrode.

25. A method for producing LiOH from a Li source, (a) The step of contacting the Li source with a solvent to extract lithium from the Li source and obtain a lithium-containing solvent, (b) The step of regenerating the lithium-containing solvent by contacting it with a stripping agent and generating a salt-containing solution containing lithium ions and negative salt ions, (c) In a membrane electrolytic cell, the salt-containing solution and O ２ A step of receiving a gas containing, (d) The step of extracting LiOH and / or acid from the membrane electrolytic cell. Methods that include...

26. A method for manufacturing a film-coated gas diffusion electrode, The steps include: preparing a coating mixture by mixing an ionomer in a solvent, The steps include applying the coating mixture to the gas diffusion electrode, The steps include curing the film to form the film-coated gas diffusion electrode and Methods that include...

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