US-12624463-B2 - Systems and methods for continuous generation of gases

US12624463B2US 12624463 B2US12624463 B2US 12624463B2US-12624463-B2

Abstract

Provided is a system for continuous generation of gases, the system including an electrochemical device and an active-material regeneration device.

Inventors

Gideon Grader
Avner Rothschild
Hen Dotan
Avigail LANDMAN
Asaf KAY
Mordechay Moshkovich

Assignees

H2PRO LTD
TECHNION RESEARCH AND DEVELOPMENT FOUNDATION LTD.

Dates

Publication Date: 20260512
Application Date: 20210804

Claims (8)

1 . A system for generation of gases, the system being arranged as a closed-loop system comprising an electrochemical device comprising one or more electrode assemblies comprising a movable electrode of a redox-active material, said movable electrode is configured for being movable between the electrochemical device and a regeneration device that is external to the electrochemical device, wherein the redox-active material is formed as a material film on a surface region of the movable electrode or wherein the movable electrode is formed of the redox-active material; and wherein the system is provided with a mechanical system configured and operable to attach and move the movable electrode from the electrochemical device to the regeneration device, wherein the mechanical system is optionally in a form or comprising a moving belt, a robotic arm, a mechanical lift or a displacing mechanism.
2 . The system according to claim 1 , wherein the electrochemical device is provided with an external closed loop system having at least one inlet and at least one outlet, the external closed loop system defining a path of a moving electrode having a segment thereof in the electrochemical device and another segment thereof extending the length of the external closed loop, wherein the at least one regeneration device is positioned between said inlet and outlet.
3 . The system according to claim 1 , wherein the movable electrode is structured as a continuous belt extending both the electrochemical device and regeneration device.
4 . The system according to claim 3 , wherein part of the electrode active material is in an oxidized form and another part of the electrode is in a reduced form, and wherein the part of the electrode moving through the electrochemical device undergoes oxidation and the part moving through the regeneration device undergoes reduction.
5 . An electrochemical device for generation of a gas utilizing an electrode being formed of or having a surface of at least one redox-active material having an oxidized form and a reduced form, the device comprising an external closed loop configured and operable to output, while the device is in operation, the electrode formed of or having the surface of the at least one redox-active material from the device to a regeneration device positioned or associated with the external closed loop, and further configured and operable to input, while the device is in operation, the electrode formed of or having the surface of the at least one redox-active material back into the device; such that the amount of the at least redox-active material on the electrode in the reduced form in the device remains substantially constant during device operation, wherein the external closed loop further comprises an electrolyte bath positioned between an outlet of the electrochemical device and an inlet of the regeneration device, and wherein the electrolyte bath is maintained at a temperature higher than the temperature of the electrolyte medium in the electrochemical device and lower than the temperature of the electrolyte medium in the regeneration device.
6 . The device according to claim 5 , wherein the external closed loop system is provided in the form of a continuous tubing or pipe or channel that comprises an electrolyte solution that is maintained under conditions substantially identical to conditions defining the electrolyte medium in the electrochemical device.
7 . A system comprising a device according to claim 5 .
8 . A continuous process for producing hydrogen gas and optionally oxygen gas in a closed-loop system comprising an electrochemical device, the electrochemical device comprising an electrode assembly and a movable electrode formed of or having a film of a redox-active material, the process comprising: while continuously generating hydrogen gas, transporting the electrode formed of or having a film of the redox-active material in an oxidized form to a region outside the electrochemical cell, said region comprising a regeneration device; generating the redox-active material and producing oxygen gas; transporting the electrode formed of or having a film of the redox-active material in a reduced form back into the electrochemical cell; and repeating the process one or more times to simultaneously produce hydrogen gas while regenerating the electrode redox-active material.

Description

TECHNOLOGICAL FIELD The present disclosure relates to electrochemical cells and methods for continuous generation of gases. BACKGROUND An electrochemical thermally activated chemical cell (E-TAC) and a system comprising a plurality of such electrochemical cells was developed [1,2], enabling alternate production of hydrogen gas and oxygen gas. In accordance with the technology, hydrogen gas is generated in an electrochemical step on a cathode electrode while charging the anode electrode, optionally by water reduction, whereas oxygen gas is generated in a spontaneous chemical step during regeneration of the anode. When shifting between one hydrogen production step to another, power is switched off and oxygen gas is produced during anode regeneration. In a system that comprises a plurality of electrochemical cells, when operation of one cell is stopped, operation of another cell may continue, thus enabling continuous production of hydrogen and oxygen gases. However, each cell works in a batch-swing mode, producing H2 at one step and O2 in a following step. Therefore, the system suffers from intrinsic fluctuations in the H2 and O2 production. BACKGROUND ART [1] International Patent Application publication WO 2016/079746.[2] International Patent Application publication WO 2019/180717. GENERAL DESCRIPTION The present invention is based on the development of an electrochemical device configured to allow a continuous generation of hydrogen gas and/or oxygen gas by utilizing a redox-active material and specifically by controlling oxidation-reduction and movement of the redox-active material in its different oxidation states throughout the device. The system of the invention enables regeneration of the electrodes, anode or cathode, without interrupting the continuous operation of the system. This is achieved by providing a system comprising two active sections or devices; one section or device being an electrochemical device which comprises an active electrode material (e.g., in a form of a flowing redox-active material) or an electrode assembly comprising at least one cathode and/or at least one anode, or a moving electrode assembly; and a second section or device, that is outside of or exterior to the first section, which acts as a regeneration device for regenerating the redox state of the active electrode material, as defined. The two sections are operably distinct but typically operable simultaneously, such that at any time point at least a portion or part of the active electrode material, either in a dispersion or suspension form or as part of an electrode, is transferred, transported or flown from the electrochemical device to the regeneration section, while the device operation continues. The redox-active material or active material is a material that has the ability to undergo reversible oxidation-reduction, under different conditions, for example different temperatures and/or different electrical bias. The active material may be provided in the device as an electrode material, in which case the active material is a material from which the electrode, e.g., an anode, is made or a material which coats a region of the electrode surface, or as a suspension or a dispersion of the active material in an electrolyte aqueous medium. Alternatively, the active material may be provided in a form of flowing capsules or may be contained in a metallic or conducting polymer carrier such as polymeric particles. The redox active material may be in a reduced form (prior to oxidation) or in an oxidized form or may be in any intermediate state (e.g., partially oxidized, partially reduced). When in a reduced form or a partially reduced form, the redox-active material is capable of undergoing oxidation to revert back to (or generate) the oxidized or partially oxidized form and vice versa. In a system of the invention, for enabling active material regeneration, each of the electrochemical devices comprises an electrode assembly wherein the active material is provided in two alternative forms: (i) The electrode assembly comprises (a) at least one cathode electrode and at least one anode electrode or (b) a moving electrode; wherein the active material is provided as an electrode material, i.e., in the form of an active film on the electrode(s); and(ii) The active material is provided as active particles dispersed in the cell medium; wherein the electrode assembly comprises at least one cathode electrode or at least one anode electrode and at least one inert electrode; or is provided in a capsule form or encapsulated within a metallic or conducting polymer carrier (a plurality of such capsules or carriers). When provided as active particles, the particles are of the electrode active material. Typically the active particles may be of a size ranging from nanometric to millimetric. In some embodiments, the particles are provided as material chunks of larger sizes and in a variety of shapes. In some embodiments, the active material is pro