AU2024201433B2

AU2024201433B2 - Electrolysis device, electrolysis system, and method of operating electrolysis device

Info

Publication number: AU2024201433B2
Application number: AU2024201433A
Authority: AU
Inventors: Ryota Kitagawa; Yasuhiro Kiyota; Yuki Kudo; Satoshi Mikoshiba; Akihiko Ono; Masakazu Yamagiwa; Maki Yonetsu
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2023-09-19
Filing date: 2024-03-05
Publication date: 2025-11-20
Anticipated expiration: 2044-03-05
Also published as: JP2025044004A; AU2024201433A1; CN119663314A; US20250092549A1; EP4527984A2; EP4527984A3

Abstract

45 An electrolysis device includes: a first electrolysis cell to reduce a reducible material and oxidize an oxidizable material; a second electrolysis cell to reduce the reducible material and oxidize the oxidizable material; a first supply source to supply a first fluid containing gas of the reducible material to the cells; a second supply source to supply a 5 second fluid containing liquid of the oxidizable material to the cells; and at least one power supply to supply a first and a second power supply current to the first and the second electrolysis cell respectively. The at least one power supply can set values of the first and second power supply currents so that a current density of current flowing through the second electrolysis cell when reducing the reducible material is higher than a current density of 10 current flowing through the first electrolysis cell when reducing the reducible material.

Description

TECHNICAL FIELD

[0001] Embodiments relate to an electrolysis device and an electrolysis system.

BACKGROUND

5 [0002] In recent years, renewable energies should be exploited by not only being 2024201433

converted into electric energy as solar power generation but also being converted into

storable and conveyable resources, in view of both an energy problem and an environment

problem. This request has developed research and development of an artificial

photosynthesis technology of generating a chemical substance using sunlight as in

10 photosynthesis by plants. This technology may enable converting renewable energy into

storable fuels, and may enable producing a chemical substance as an industrial raw

material to create valuables.

[0003] Examples of an apparatus, which produces the chemical substance using the

renewable energy of solar power generation, include an electrolysis device

15 (electrochemical reaction device) such as a carbon dioxide electrolysis device having a

cathode and a anode, the cathode reducing carbon dioxide (CO2) generated from a power

station or a waste treatment plant, and the anode oxidizing water (H2O). The cathode can

reduce carbon dioxide to produce a carbon compound such as carbon monoxide (CO), for

example. When the electrolysis device is composed by forming a cell (also referred to as

20 an electrolysis cell), it is considered effective to compose the electrolysis device by

forming a cell similar to a cell of a fuel cell such as Polymer Electric Fuel Cell (PEFC), for

example. The carbon dioxide electrolysis device can directly supply carbon dioxide to a

catalyst layer of the cathode to speedily reduce the carbon dioxide. Further, the carbon

dioxide electrolysis device can have a stack structure, which is formed by stacking

25 electrolysis cells, to prevent an increase of the area of the carbon dioxide electrolysis

device and to efficiently reduce the carbon dioxide.

[0003a] It is desired to address or alleviate one or more disadvantages or limitations of the

prior art, or to at least provide a useful alternative.

Patent Reference

[0004] Reference 1: US 2011/025643 A1

Reference 2: US 7147953 B2

5 Reference 3: JP 2022-42280 A 2024201433

[0005] Reference 4: ACS Energy Lett. 2019, 4, 1770-1777

SUMMARY

10 [0006] A problem to be solved by the present invention is to suppress unnecessary

current consumption in an electrolytic reaction of an electrolysis device.

[0007] One or more embodiments of the present invention comprise an electrolysis

device according to an embodiment includes: a first electrolysis cell configured to reduce a

reducible material and to oxidize an oxidizable material; a second electrolysis cell

15 configured to reduce the reducible material and to oxidize the oxidizable material; a first

supply source configured to supply a first fluid to the first electrolysis cell and the second

electrolysis cell, the first fluid containing a gas of the reducible material; a second supply

source configured to supply a second fluid to the first electrolysis cell and the second

electrolysis cell, the second fluid containing a liquid of the oxidizable material; and at least

20 one power supply configured to supply a first power supply current to the first electrolysis

cell and to supply a second power supply current to the second electrolysis cell. The at

least one power supply is configured to set a value of the first power supply current and a

value of the second power supply current so that a current density of current flowing

through the second electrolysis cell when reducing the reducible material is higher than a

25 current density of current flowing through the first electrolysis cell when reducing the

reducible material, wherein: the first electrolysis cell has: a first membrane electrode

assembly having a first cathode, a first anode, and a first diaphragm between the first

cathode and the first anode; a first cathode flow path plate having a first cathode flow path

facing on the first cathode; and a first anode flow path plate having a first anode flow path

facing on the first anode; the second electrolysis cell has: a second membrane electrode

assembly having a second cathode, a second anode, and a second diaphragm between the

second cathode and the second anode; a second cathode flow path plate having a second

cathode flow path facing on the second cathode; and a second anode flow path plate having

5 a second anode flow path facing on the second anode, and the device further comprises: a 2024201433

first cathode current collector electrically connected to the first cathode and the at least one

power supply; a first anode current collector electrically connected to the first anode and

the at least one power supply; a second cathode current collector electrically connected to

the second cathode and the at least one power supply; and a second anode current collector

10 electrically connected to the second anode and the at least one power supply.

[0007a] Further embodiments of the present invention comprise a method of operating an

electrolysis device, the device comprising: a first electrolysis cell configured to reduce a

configured to reduce the reducible material and to oxidize the oxidizable material; a first

15 supply source configured to supply a first fluid to the first electrolysis cell and the second

one power supply configured to supply a first power supply current to the first electrolysis

20 cell and to supply a second power supply current to the second electrolysis cell, wherein:

the first electrolysis cell has: a first membrane electrode assembly having a first cathode, a

first anode, and a first diaphragm between the first cathode and the first anode; a first

cathode flow path plate having a first cathode flow path facing on the first cathode; and a

first anode flow path plate having a first anode flow path facing on the first anode; the

25 second electrolysis cell has: a second membrane electrode assembly having a second

cathode, a second anode, and a second diaphragm between the second cathode and the

second anode; a second cathode flow path plate having a second cathode flow path facing

on the second cathode; and a second anode flow path plate having a second anode flow

path facing on the second anode, and the device further comprises: a first cathode current

collector electrically connected to the first cathode and the at least one power supply; a

first anode current collector electrically connected to the first anode and the at least one

power supply; a second cathode current collector electrically connected to the second

5 cathode and the at least one power supply; and a second anode current collector electrically 2024201433

connected to the second anode and the at least one power supply, the method comprising:

supplying the first fluid to the first electrolysis cell and the second electrolysis cell, and

supplying the second fluid to the first electrolysis cell and the second electrolysis cell; and

supplying the first power supply current to the first electrolysis cell to reduce the reducible

10 material, and supplying the second power supply current to the second electrolysis cell to

reduce the reducible material, wherein a current density of a current flowing through the

second electrolysis cell when reducing the reducible material is higher than a current

density of a current flowing through the first electrolysis cell when reducing the reducible

material.

15

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] One or more embodiments of the present invention are hereinafter described, by

way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a schematic view illustrating a configuration example of an electrolysis

20 device in an embodiment.

FIG. 2 is a perspective schematic view illustrating an example structure of a cell

structure 100.

FIG. 3 is a schematic view illustrating an example structure of a membrane

electrode assembly MEA.

25 FIG. 4 is a schematic view illustrating an example structure of a cathode flow path

plate 14.

FIG. 5 is a schematic view illustrating an example structure of an anode flow path

plate 15.

FIG. 6 is a schematic view illustrating an example structure of a cathode current

collector 16.

FIG. 7 is a schematic view illustrating an example structure of an anode current

collector 17.

5 FIG. 8 is a schematic view illustrating an example structure of an insulating layer 2024201433

18.

FIG. 9 is a schematic view for explaining the flow of a cathode fluid and the flow

of an anode fluid in the cell structure 100.

FIG. 10 is a perspective schematic view illustrating an example structure of the

10 cell structure 100.

FIG. 11 is a schematic view illustrating an appearance in which an impurity and a

reducible material in the cathode fluid flow in series through electrolysis cells 10.

FIG. 12 is a chart illustrating examples of graphs indicating the relation among a

current density flowing through the electrolysis cell 10, a cell voltage, and a Faraday

15 efficiency.

FIG. 13 is a schematic view illustrating another example of the electrolysis device

in the embodiment.

FIG. 14 is a schematic view illustrating another example of the electrolysis device

in the embodiment.

20 FIG. 15 is a schematic view illustrating another example of the electrolysis device

in the embodiment.

FIG. 16 is a schematic view illustrating another example of the electrolysis device

in the embodiment.

25 DETAILED DESCRIPTION

[0009] Electrolysis devices in embodiments will be explained below with reference to

the drawings. In the embodiments explained below, substantially the same components are

denoted by the same reference signs and the explanation thereof will be partially omitted in

some cases. The drawings are schematic, in which the relationship between the thickness

and planar dimensions, a thickness ratio among the components, and so on may be

different from actual ones.

[0010] In this specification, "connecting" includes not only directly connecting but also

5 indirectly connecting unless otherwise specified. Further, in this specification, 2024201433

"connecting" includes not only physically connecting but also electrically connecting

unless otherwise specified.

[0011] FIG. 1 is a schematic view illustrating a configuration example of an electrolysis

device in an embodiment. FIG. 1 illustrates a configuration example of an electrolysis

10 device 1. The electrolysis device 1 includes an electrolysis cell 10 which performs an

electrolytic reaction, a cathode supply source 20 which supplies cathode a fluid, an anode

supply source 30 which supplies an anode fluid, and a power supply 40 which feeds power

to the electrolysis cell 10. FIG. 1 illustrates an X-axis, a Y-axis, and a Z-axis. The X-axis,

the Y-axis, and the Z-axis vertically cross one another. The Z-axis is along a thickness

15 direction of the electrolysis cell 10. FIG. 1 illustrates a part of an X-Z cross section

including the X-axis and the Z-axis.

[0012] The electrolysis cell 10 has a cathode 11, an anode 12, a diaphragm (separator)

13, a cathode flow path plate 14 having a cathode flow path 140, an anode flow path plate

15 having an anode flow path 150, a cathode current collector 16, and an anode current

20 collector 17. The cathode 11, the anode 12, and the diaphragm 13 may be stacked to form

a membrane electrode assembly MEA. The order of stacking the components of the

electrolysis cell 10 is not limited to that in FIG. 1, but they may be stacked, for example, in

an order reverse to the order illustrated in FIG. 1.

[0013] The electrolysis device 1 has a plurality of the electrolysis cells 10. The

25 electrolysis cells 10 are stacked, for example, with an insulating layer 18 intervening

therebetween to form a cell structure 100 such as a cell stack. FIG. 2 is a perspective

schematic view illustrating an example structure of the cell structure 100. The cell

structure 100 further has an insulating layer 18 between two stacked electrolysis cells 10.

The stacked electrolysis cells 10 may be sandwiched between a pair of supporting plates

and further fastened with bolts or the like. FIG. 1 and FIG. 2 illustrate electrolysis cells

10_1, 10_2, 10_3 as the electrolysis cells 10, but the number of electrolysis cells 10 only

needs to be two or more and is not limited to the number illustrated in FIG. 1 and FIG. 2.

5 [0014] The cathode 11 is an electrode (a reduction electrode) for causing, for example, a 2024201433

reduction reaction of at least one reducible material (at least one substance to be reduced)

to produce a reduction product. The at least one reducible material includes, for example,

carbon dioxide or nitrogen. The cathode 11 is in contact with the diaphragm 13. The

cathode 11 is an electrode (a reduction electrode) for causing a reduction reaction of the

10 reducible material to produce the reduction product. Examples of the reducible material

include carbon dioxide, nitrogen, hydrogen, oxygen, reduction product, and so on.

Examples of the reduction product include carbon compound, ammonia, and so on.

Examples of the carbon compound include carbon monoxide (CO), methane (CH4), ethane

(C2H6), and so on. The reduction reaction at the cathode 11 may include a side reaction of

15 causing a reduction reaction of water to produce hydrogen (H2). Further, the reduction

reaction at the cathode 11 may include a side reaction of causing a reduction reaction of

carbon dioxide and a reduction reaction of oxygen to produce water (H2O).

[0015] The cathode 11 is supplied with the anode fluid and ions from the diaphragm 13

and is supplied with the cathode fluid from the cathode flow path 140. The cathode 11

20 may have a gas diffusion layer and a cathode catalyst layer provided on the gas diffusion

layer. The cathode 11 may further have a porous layer denser than the gas diffusion layer,

between the gas diffusion layer and the cathode catalyst layer. The gas diffusion layer is

arranged adjacent to the cathode flow path 140, and the cathode catalyst layer is arranged

adjacent to the diaphragm 13. The cathode catalyst layer may extend into the gas diffusion

25 layer. The cathode catalyst layer preferably has a catalyst nanoparticle, a catalyst

nanostructure, or the like. The gas diffusion layer is composed of, for example, carbon

paper, carbon cloth, or the like, and may have been subjected to a water repellent

treatment. The porous layer is composed of a porous member smaller in pore size than the

carbon paper or carbon cloth.

[0016] An appropriate water repellent treatment to the gas diffusion layer allows a carbon

dioxide gas to reach the cathode catalyst layer mainly by gas diffusion. The reduction

reaction of the carbon dioxide and the reduction reaction of a carbon compound produced

5 thereby occur near the boundary between the gas diffusion layer and the cathode catalyst 2024201433

layer or near the cathode catalyst layer intruding into the gas diffusion layer.

[0017] The cathode catalyst layer preferably contains a catalyst material (cathode catalyst

material) capable of decreasing an overvoltage of the reduction reaction. Examples of the

material include metals such as gold (Au), silver (Ag), copper (Cu), platinum (Pt),

10 palladium (Pd), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), titanium (Ti),

cadmium (Cd), zinc (Zn), indium (In), gallium (Ga), lead (Pb), and tin (Sn), metal

materials such as alloys and intermetallic compounds containing at least one of the metals,

carbon materials such as carbon (C), graphene, CNT (carbon nanotube), fullerene, and

ketjen black, and metal complexes such as a Ru complex and a Re complex. To the

15 cathode catalyst layer, various shapes such as a plate shape, a mesh shape, a wire shape, a

particle shape, a porous shape, a thin film shape, or an island shape can be applied.

[0018] The cathode catalyst material constituting the cathode catalyst layer preferably

has a nanoparticle of the above metal material, a nanostructure of the metal material, a

nanowire of the metal material, or a composite in which the nanoparticle of the metal

20 material is supported by a carbon material such as carbon particle, carbon nanotube, or

graphene. The use of the catalyst nanoparticle, the catalyst nanostructure, a catalyst

nanowire, a catalyst nanosupport structure, or the like, as the cathode catalyst material can

enhance the reaction efficiency of the reduction reaction of carbon dioxide at the cathode

11.

25 [0019] The anode 12 is provided between the diaphragm 13 and the anode flow path 150

and is in contact with them. The anode 12 is an electrode (an oxidization electrode) for

oxidizing water (H2O) in an anode solution contained in the anode fluid to produce oxygen

(O2) and hydrogen ions (H+) or an electrode for oxidizing hydroxide ions (OH−) produced

by the reduction reaction of carbon dioxide at the cathode 11 to produce oxygen and water.

[0020] The anode 12 preferably contains a catalyst material (a anode catalyst material)

capable of decreasing an overvoltage of the oxidation reaction. Examples of the catalyst

material include metals such as platinum (Pt), palladium (Pd), and nickel (Ni), alloys and

5 intermetallic compounds containing those metals, binary metal oxides such as manganese 2024201433

oxide (Mn-O), iridium oxide (Ir-O), nickel oxide (Ni-O), cobalt oxide (Co-O), iron oxide

(Fe-O), tin oxide (Sn-O), indium oxide (In-O), ruthenium oxide (Ru-O), lithium oxide (Li-

O), and lanthanum oxide (La-O), ternary metal oxides such as Ni-Co-O, Ni-Fe-O, La-Co-

O, Ni-La-O, and Sr-Fe-O, quaternary metal oxides such as Pb-Ru-Ir-O and La-Sr-Co-O,

10 and metal complexes such as a Ru complex and a Fe complex.

[0021] The anode 12 includes a base material having a structure capable of moving liquid

and ions between the diaphragm 13 and the anode flow path 150, for example, a porous

structure such as a mesh material, a punched material, a porous member, or a metal fiber

sintered compact. The base material may be composed of a metal such as titanium (Ti),

15 nickel (Ni), or iron (Fe) or a metal material such as an alloy (for example SUS) containing

at least one of the metals, or may be composed of the aforementioned anode catalyst

material. In the case of using an oxide as the anode catalyst material, it is preferable to

bond or stack the anode catalyst material on the surface of the base material composed of

the above metal material to form a catalyst layer. The anode catalyst material preferably

20 has a nanoparticle, a nanostructure, a nanowire, or the like in order to enhance the

oxidation reaction. The nanostructure is a structure obtained by forming nanoscale

irregularities on the surface of the catalyst material. The oxidation catalyst does not always

need to be provided at the anode 12. An oxidation catalyst layer provided other than the

anode 12 may be electrically connected to the anode 12.

25 [0022] The diaphragm 13 is provided between the cathode 11 and the anode 12. The

diaphragm 13 is arranged to separate the cathode 11 and the anode 12 from each other.

The diaphragm 13 includes an ion exchange membrane capable of moving ions between

the cathode 11 and the anode 12 and separating the cathode 11 and the anode 12 from each

other. Examples of the usable ion exchange membrane include a cation exchange

membrane such as Nafion or Flemion, or an anion exchange membrane such as Neosepta,

Selemion, or Sustainion. In the case of assuming the movement of mainly OH− by using

an alkaline solution for the electrolytic solution, the diaphragm 13 is preferably composed

5 of an anion exchange membrane. The ion exchange membrane may be composed using a 2024201433

film using hydrocarbon as a basic structure or a film having an amine group. However,

other than the ion exchange membrane, a salt bridge, a glass filter, a porous polymer

membrane, a porous insulating material, or the like, as long as it is a material capable of

moving ions between the cathode 11 and the anode 12, may be applied to the diaphragm

10 13. However, if passage of gas occurs between the cathode 11 and the anode 12, a circular

reaction due to reoxidation of the reduction product may occur. Therefore, it is preferable

that there is less exchange of gas between the cathode 11 and the anode 12. Therefore, it is

necessary to take care when using a thin film of a porous member as the diaphragm 13.

[0023] The cathode flow path plate 14 has the cathode flow path 140. The cathode flow

15 path 140 faces on the cathode 11. The cathode flow path 140 allows the cathode fluid to be

supplied to the cathode 11 and containing the reducible material to flow therethrough. The

cathode fluid may contain water vapor by humidification. The reduction product is mainly

discharged from the cathode flow path 140 while being contained in the cathode fluid. The

reduction product is different depending on the type of the reduction catalyst or the like.

20 Together with the gas products, vapor or moisture obtained by dew condensation of vapor

contained in the humidified carbon dioxide gas is drained from the cathode flow path 140.

[0024] The reduction product is different also depending on the composition of the

cathode fluid. In the case where the cathode fluid contains a carbon dioxide gas or a

humidified carbon dioxide gas, a carbon monoxide gas and a reduction product such as

25 hydrogen as a by-product are mainly produced. In the case where the cathode fluid

contains a nitrogen gas, a reduction product such as ammonia is mainly produced. In the

case where the cathode fluid contains an impurity gas such as oxygen, oxygen is reduced to

produce water as a reduction product.

[0025] The cathode flow path 140 is provided on the surface of the cathode flow path

plate 14. The cathode flow path plate 14 has a groove (recessed portion) which forms the

cathode flow path 140 on the surface. The cathode flow path plate 14 is preferably formed

using a material low in chemical reactivity and high in conductivity. Examples of the

5 material include metal materials such as Ti and SUS, carbon, and the like. Examples of the 2024201433

material of the flow path plate include a material low in chemical reactivity and having no

conductivity. Examples of the material include insulating resin materials such as an acrylic

resin, polyether ether ketone (PEEK), and a fluorocarbon resin. The cathode flow path

plate 14 has a not-illustrated screw hole for fastening. Further, before and after cathode

10 flow path plates 14, not-illustrated packing may be sandwiched as necessary. The cathode

flow path 140 may be provided in the cathode current collector 16.

[0026] The cathode flow path 140 has an inlet and an outlet, is supplied with the cathode

fluid from the cathode supply source 20 through the inlet, and discharges an unreacted

reducible material and the reduction product through the outlet. The cathode fluid flows

15 through the inside of the cathode flow path 140 in a manner to be in contact with the

cathode 11. The cathode fluid discharged from the cathode flow path 140 may contain the

unreacted reducible material, the reduction product, and so on.

[0027] The cathode flow path 140 may have a land in contact with the cathode 11 for

electrical connection with the cathode 11. The shape of the cathode flow path 140 is not

20 particularly limited, and can be a serpentine structure obtained by folding an elongated

flow path or the like. Thus, it is preferable that the cathode fluid uniformly flows on the

surface of the cathode 11, thereby allowing a uniform reaction to be performed at the

cathode 11.

[0028] The cathode fluid may be supplied in a dry state. In the case where the cathode

25 fluid contains a carbon dioxide gas, a carbon dioxide concentration of the cathode fluid to

be supplied from the cathode supply source 20 to the cathode flow path 140 does not have

to be 100%. It is also possible to use fluid containing the carbon dioxide gas discharged

from various facilities, as the cathode fluid. In this case, the cathode fluid may contain an

impurity gas. Assuming that a first gas contained in the cathode fluid is the carbon dioxide

gas, a second gas is a substance different from carbon dioxide, such as oxygen or nitrogen.

The concentration of the second gas is preferably lower than the concentration of the first

gas and is, for example, 1 ppm or higher and 100000 ppm or lower.

5 [0029] The cathode flow path plate 14 is mainly formed of one member, but may be 2024201433

formed of a plurality of different members and constructed by stacking them. Further, a

surface treatment may be performed partially or entirely on the cathode flow path plate 14

to add a hydrophilic or water repellent function to the cathode flow path plate 14.

[0030] The anode flow path plate 15 has the anode flow path 150. The anode flow path

10 150 faces on the anode 12. The anode flow path 150 allows the anode fluid to be supplied

to the anode 12 to flow therethrough. The anode fluid contains liquid such as the anode

solution.

[0031] The anode solution preferably contains at least water (H2O). For example, in the

case where the reducible material is carbon dioxide, carbon dioxide is supplied from the

15 cathode flow path 140, so that the anode solution may or may not contain carbon dioxide.

[0032] As the anode solution, an aqueous solution (electrolytic solution) containing metal

ions can be used. Examples of the aqueous solution include aqueous solutions containing

phosphate ion (PO42−), borate ion (BO33−), sodium ion (Na+), potassium ion (K+), calcium

ion (Ca2+), lithium ion (Li+), cesium ion (Cs+), magnesium ion (Mg2+), chloride ion (Cl−),

20 hydrogen carbonate ion (HCO3−), and so on. In addition, aqueous solutions containing

lithium hydrogen carbonate (LiHCO3), sodium hydrogen carbonate (NaHCO3), potassium

hydrogen carbonate (KHCO3), cesium hydrogen carbonate (CsHCO3), phosphoric acid,

boric acid, and so on may be used.

[0033] The anode flow path 150 is provided on the surface of the anode flow path plate

25 15. The anode flow path plate 15 is for supplying the anode fluid to the anode 12, and has

a groove (recessed portion) which forms the anode flow path 150 on the surface. The

anode flow path plate 15 is preferably formed using a material low in chemical reactivity

and high in conductivity. Examples of the material include metal materials such as Ti and

SUS, carbon, and so on. The anode flow path 150 may be provided at the anode current

collector 17. Further, examples of the material of the anode flow path plate 15 include a

material low in chemical reactivity and having no conductivity. Examples of the material

include insulating resin materials such as an acrylic resin, polyether ether ketone (PEEK),

5 and a fluorocarbon resin. The anode flow path plate 15 has a not-illustrated screw hole for 2024201433

fastening.

[0034] The anode flow path plate 15 is mainly formed of one member, but may be

surface treatment may be performed partially or entirely on the anode flow path plate 15 to

10 add a hydrophilic or water repellent function to the anode flow path plate 15.

[0035] The anode flow path 150 has an inlet and an outlet, is supplied with the anode

fluid from the anode supply source 30 through the inlet, and discharges the anode fluid

through the outlet. The anode fluid flows through the inside of the anode flow path 150 in

a manner to be in contact with the anode 12. The anode fluid discharged from the anode

15 flow path 150 may contain an unreacted oxidizable material, an oxidation product, and so

on.

[0036] The anode flow path 150 may have a land in contact with the anode 12 for

electrical connection with the anode 12. The shape of the anode flow path 150 is not

particularly limited, and can be a serpentine structure obtained by folding an elongated

20 flow path or the like. Thus, it is preferable that the anode fluid uniformly flows on the

surface of the anode 12, thereby allowing a uniform reaction to be performed at the anode

12.

[0037] The cathode current collector 16 is electrically connected to the cathode 11. The

cathode current collector 16 is in contact with a surface of the cathode flow path plate 14

25 across the cathode flow path plate 14 from the cathode flow path 140. The cathode current

collector 16 preferably contains a material low in chemical reactivity and high in

conductivity. Examples of the material include metal materials such as Ti and SUS,

carbon, and so on.

[0038] The anode current collector 17 is electrically connected to the anode 12. The

anode current collector 17 is in contact with a surface of the anode flow path plate 15

across the anode flow path plate 15 from the anode flow path 150. The anode current

collector 17 preferably contains a material low in chemical reactivity and high in

5 conductivity. Examples of the material include metal materials such as Ti and SUS, 2024201433

carbon, and so on.

[0039] The insulating layer 18 is provided between two electrolysis cells 10. The

insulating layer 18 is formed using a material such as a material coated with a fluorocarbon

resin such as silicone or polytetrafluoroethylene (PTFE), an insulating resin material such

10 as an acrylic resin, polyether ether ketone (PEEK), or a fluorocarbon resin, or the like. The

electrolysis device 1 may have a plurality of the insulating layers 18.

[0040] The cathode supply source 20 can supply the cathode fluid to, for example, the

electrolysis cell 10. The cathode supply source 20 is connected to the cathode flow path

140 of the electrolysis cell 10_1 via, for example, a pipe.

15 [0041] The anode supply source 30 can supply the anode fluid to, for example, the

electrolysis cell 10. The anode supply source 30 is connected to the anode flow path 150

of the electrolysis cell 10_1 via, for example, a pipe.

[0042] The power supply 40 can supply power supply currents to the electrolysis cells

10, for example. The power supply 40 is electrically connected to the cathode current

20 collectors 16 of the electrolysis cells 10 via at least one wire. The cathode current

collectors 16 may be electrically connected in parallel with one another. The power supply

40 is electrically connected to the anode current collectors 17 of the electrolysis cells 10

via at least one wire. The anode current collectors 17 may be electrically connected in

parallel with one another.

25 [0043] Examples of the power supply 40 are not limited to a normal system power

supply or battery, but examples of the power supply 40 may include a power supply which

supplies power generated with renewable energy of a solar cell, wind power generation, or

the like. The use of the renewable energy is preferable in terms of environment in addition

to the effective utilization of the reducible material. The power supply 40 may further

have a power controller that adjusts an output of the power supply 40 to control the voltage

between the cathode 11 and the anode 12. The power supply 40 may be provided outside

the electrolysis device 1. The power supply 40 controls the current or voltage to be

5 supplied to each electrolysis cell 10 to enable optimally operating the electrolysis cell 10 2024201433

and enhance the reaction efficiency of the reduction reaction of the reducible material at

the cathode 11. Further, the power supply 40 can adjust the current or voltage to be

supplied to each electrolysis cell 10 to enable optimally operating the electrolysis cell 10

10 the cathode 11. The electrolysis device 1 may have an element for monitoring the current,

the element being provided on connection between the power supply 40 and the

electrolysis cell 10 or connection between the power supply 40 and the cell structure 100,

and examples of the element including a resistor element. This can control the voltage to

enable optimally operating the electrolysis cell 10 and enhance the reaction efficiency of

15 the reduction reaction at the cathode 11.

[0044] The cathode fluid and the anode fluid can be supplied to flow in series or in

parallel through the electrolysis cells 10. In the case of supplying the cathode fluid and the

anode fluid to make them flow in series through the electrolysis cells 10, the electrolysis

cells 10 may be configured such that the cathode flow paths 140 are connected in series

20 and the anode flow paths 150 are connected in series. An example structure of the

components of the electrolysis cell 10 in the case where the cathode flow paths 140 are

connected in series and the anode flow paths 150 are connected in series, will be explained

below.

[0045] FIG. 3 is a schematic view illustrating an example structure of the membrane

25 electrode assembly MEA. FIG. 3 illustrates an X-Y plane view. The membrane electrode

assembly MEA may be surrounded by a supporting plate 130. The supporting plate 130

has, for example, an opening 130a and an opening 131. The opening 130a is provided

through the supporting plate 130 in a Z-axis direction, and is a space in which the

membrane electrode assembly MEA is arranged. The opening 131 is provided through the

supporting plate 130 in the Z-axis direction, and examples of the opening 131 include a

through hole such as a via. The supporting plate 130 has a plurality of the openings 131.

The openings 131 are provided around the opening 130a. One of the openings 131 allows

5 the cathode fluid to flow therethrough. Another of the openings 131 allows the anode fluid 2024201433

to flow therethrough. FIG. 3 illustrates an opening 131_1 and an opening 131_2 as the

openings 131, but the number of the openings 131 only needs to be two or more and is not

limited to the number illustrated in FIG. 3. The opening 131_1 allows the cathode fluid to

flow therethrough. The opening 131_2 allows the anode fluid to flow therethrough. The

10 supporting plate 130 is preferably formed using an insulating material. The above

configuration is one example, and the openings 131 may be provided in another member

such as the cathode 11 or the anode 12 in place of the supporting plate 130 as long as the

cathode fluid and the anode fluid can pass, without leakage, through a layer including the

membrane electrode assembly MEA.

15 [0046] FIG. 4 is a schematic view illustrating an example structure of the cathode flow

path plate 14. FIG. 4 illustrates an X-Y plane view. The cathode flow path plate 14 has,

for example, the cathode flow path 140 and an opening 141. The cathode flow path 140 is

provided adjacent to the membrane electrode assembly MEA of the cathode flow path plate

14, and may be formed in a serpentine shape along an X-Y plane as illustrated in FIG. 14

20 or may have another shape. The opening 141 is provided through the cathode flow path

plate 14 in the Z-axis direction, and examples of the opening 141 include a through hole

such as a via. The cathode flow path plate 14 has a plurality of the openings 141. One of

the openings 141 allows the cathode fluid to flow therethrough. Another of the openings

141 allows the anode fluid to flow therethrough. FIG. 4 illustrates an opening 141_1, an

25 opening 141_2, and an opening 141_3 as the openings 141, but the number of the openings

141 only needs to be two or more and is not limited to the number illustrated in FIG. 4.

The cathode flow path 140 is connected to the opening 131_1. The opening 141_1 is

provided on a surface of the cathode flow path plate 14, the surface being provided across

the cathode flow path plate 14 from the formation surface of the cathode flow path 140.

The opening 141_1 overlaps with one end of the cathode flow path 140. The opening

141_1 is connected to the cathode flow path 140. The opening 141_2 is connected, for

example, to the opening 131_2. Another end of the cathode flow path 140 overlaps with,

5 for example, the opening 131_1. The opening 141_1 allows the cathode fluid to flow 2024201433

therethrough. The opening 141_2 allows the anode fluid to flow therethrough.

[0047] FIG. 5 is a schematic view illustrating an example structure of the anode flow

path plate 15. FIG. 5 illustrates an X-Y plane view. The anode flow path plate 15 has, for

example, the anode flow path 150 and an opening 151. The anode flow path 150 may be

10 formed in a serpentine shape along an X-Y plane as illustrated in FIG. 5 or may have

another shape. The opening 151 is provided through the anode flow path plate 15 in the Z-

axis direction, and examples of the opening 151 include a through hole such as a via. The

anode flow path plate 15 has a plurality of the openings 151. One of the openings 151

allows the cathode fluid to flow therethrough. Another of the openings 151 allows the

15 anode fluid to flow therethrough. FIG. 5 illustrates an opening 151_1 and an opening

151_2 as the openings 151, but the number of openings 151 only needs to be two or more

and is not limited to the number illustrated in FIG. 5. The opening 151_1 is connected, for

example, to the opening 131_1. The opening 151_2 is provided on a surface of the anode

flow path plate 15, the surface being across the anode flow path plate 15 from the

20 formation surface of the anode flow path 150. The opening 151_2 overlaps with one end

of the anode flow path 150. The opening 151_2 is connected, for example, to the opening

131_2. The opening 151_1 allows the cathode fluid to flow therethrough. The opening

151_2 allows the anode fluid to flow therethrough.

[0048] FIG. 6 is a schematic view illustrating an example structure of the cathode current

25 collector 16. FIG. 6 illustrates an X-Y plane view. The cathode current collector 16 has,

for example, an opening 161. The opening 161 is provided through the cathode current

collector 16 in the Z-axis direction, and examples of the opening 161 include a through

hole such as a via. The cathode current collector 16 has a plurality of the openings 161.

One of the openings 161 allows the cathode fluid to flow therethrough. Another of the

openings 161 allows the anode fluid to flow therethrough. FIG. 6 illustrates an opening

161_1 and an opening 161_2 as the openings 161, but the number of the openings 161 only

needs to be two or more and is not limited to the number illustrated in FIG. 6. The opening

5 161_1 is connected, for example, to the opening 161_1. The opening 161_2 is connected, 2024201433

for example, to the opening 141_2. The opening 161_1 allows the cathode fluid to flow

therethrough. The opening 161_2 allows the anode fluid to flow therethrough.

[0049] FIG. 7 is a schematic view illustrating an example structure of the anode current

collector 17. FIG. 7 illustrates an X-Y plane view. The anode current collector 17 has, for

10 example, an opening 171. The opening 171 is provided through the anode current collector

17 in the Z-axis direction, and examples of the opening 171 include a through hole such as

a via. The anode current collector 17 has a plurality of the openings 171. One of the

openings 171 allows the cathode fluid to flow therethrough. Another of the openings 171

allows the anode fluid to flow therethrough. FIG. 7 illustrates an opening 171_1 and an

15 opening 171_2 as the openings 171, but the number of the openings 171 only needs to be

two or more and is not limited to the number illustrated in FIG. 7. The opening 171_1 is

connected, for example, to the opening 151_1. The opening 171_2 is connected, for

example, to the opening 151_2. The opening 171_1 allows the cathode fluid to flow

therethrough. The opening 171_2 allows the anode fluid to flow therethrough.

20 [0050] FIG. 8 is a schematic view illustrating an example structure of the insulating layer

18. FIG. 8 illustrates an X-Y plane view. The insulating layer 18 has, for example, an

opening 181. The opening 181 is provided through the insulating layer 18 in the Z-axis

direction, examples of the opening 18 include a through hole such as a via. The insulating

layer 18 has a plurality of the openings 181. One of the openings 181 allows the cathode

25 fluid to flow therethrough. Another of the openings 181 allows the anode fluid to flow

therethrough. FIG. 8 illustrates an opening 181_1 and an opening 181_2 as the openings

181, but the number of the openings 181 only needs to be two or more and is not limited to

the number illustrated in FIG. 8. The opening 181_1 is connected, for example, to the

opening 171_1. The opening 181_2 is connected, for example, to the opening 171_2. The

opening 181_1 allows the cathode fluid to flow therethrough. The opening 181_2 allows

the anode fluid to flow therethrough.

[0051] When the electrolysis cells 10 are stacked with the insulating layer 18 intervening

5 therebetween, positions of the openings 131, the openings 141, the openings 151, the 2024201433

openings 161, the openings 171, and the openings 181 may be different between an

electrolysis cell 10_2n−1 (n is a natural number) at an odd stage such as the electrolysis

cell 10_1 and an electrolysis cell 10_2n (n is a natural number) at an even stage such as the

electrolysis cell 10_2. For example, positions of the opening 131_1 and the opening

10 131_2, positions of the opening 141_1 and the opening 141_2, positions of the opening

151_1 and the opening 151_2, positions of the opening 161_1 and the opening 161_2,

positions of the opening 171_1 and the opening 171_2, and positions of the opening 181_1

and the opening 181_2 each may have a symmetrical relationship between the electrolysis

cell 10_2n−1 (n is a natural number) at the odd stage and the electrolysis cell 10_2n (n is a

15 natural number) at the even stage. Further, depending on the shape of the flow path,

positions of the opening 131_1 and the opening 131_2, positions of the opening 141_1 and

the opening 141_2, positions of the opening 151_1 and the opening 151_2, positions of the

opening 161_1 and the opening 161_2, positions of the opening 171_1 and the opening

171_2, and positions of the opening 181_1 and the opening 181_2 each may have an

20 asymmetrical relationship between the electrolysis cell 10_2n−1 (n is a natural number) at

the odd stage and the electrolysis cell 10_2n (n is a natural number) at the even stage. In

the case where packing is provided, the packing may be provided with a plurality of

openings, and through which the cathode fluid and the anode fluid may be allowed to pass.

[0052] The flow of the cathode fluid and the flow of the anode fluid in each electrolysis

25 cell 10 in supplying the cathode fluid and the anode fluid so that they flow in series

through the electrolysis cells 10 will be explained with reference to FIG. 9 and FIG. 10.

FIG. 9 and FIG. 10 are schematic views for explaining the flow of the cathode fluid and

the flow of the anode fluid in the electrolysis cells 10. Arrows of solid lines illustrated in

FIG. 9 and FIG. 10 indicate the flow of the cathode fluid. Arrows of dotted lines in FIG. 9

and FIG. 10 indicate the flow of the anode fluid.

[0053] In the electrolysis cell 10_2n−1 at the odd stage such as the electrolysis cell 10_1

at a first stage, as illustrated in FIG. 9, the cathode fluid passes through the opening 161_1,

5 passes through the opening 141_1, moves from one end to the other end of the cathode 2024201433

flow path 140, passes through the opening 131_1, passes through the opening 151_1,

passes through the opening 171_1, and passes through the opening 181_1, and thereby can

move to the electrolysis cell 10 at a next stage.

[0054] In the electrolysis cell 10_2n−1 at the odd stage, as illustrated in FIG. 9, the anode

10 fluid passes through the opening 161_2, passes through the opening 141_2, passes through

the opening 131_2, moves from one end to the other end of the anode flow path 150,

passes through the opening 151_2, passes through the opening 171_2, and passes through

the opening 181_2, and thereby can move to the electrolysis cell 10 at the next stage.

[0055] In the electrolysis cell 10_2n at the even stage such as the electrolysis cell 10_1 at

15 a second stage, as illustrated in FIG. 10, the cathode fluid passes through the opening

161_1, passes through the opening 141_1, moves from one end to the other end of the

cathode flow path 140, passes through the opening 131_1, passes through the opening

151_1, passes through the opening 171_1, and passes through the opening 181_1, and

thereby can move to an electrolysis cell 10 at a next stage.

20 [0056] In the electrolysis cell 10_2n−1 at the odd stage, as illustrated in FIG. 9, the anode

fluid passes through the opening 161_2, passes through the opening 141_2, passes through

25 [0057] Next, an example method of operating the electrolysis device 1 will be explained.

Here, the case of producing carbon monoxide as the carbon compound will be mainly

explained, but the reduction product of carbon dioxide is not limited to the carbon

compound.

[0058] First, a reaction process in the case of oxidizing mainly water (H2O) to produce

hydrogen ions (H+) will be explained. When the cathode fluid is supplied from the cathode

supply source 20 to the cathode flow path 140, the anode fluid is supplied from the anode

supply source 30 to the anode flow path 150, and current is supplied between the cathode

5 11 and the anode 12 from the power supply 40, an oxidation reaction of water (H2O) 2024201433

occurs at the anode 12 in contact with the anode solution. Specifically, H2O contained in

the anode solution is oxidized to produce oxygen (O2) and hydrogen ions (H+) as expressed

in Formula (1) below.

[0059] 2H2O → 4H+ + O2 + 4e− ... (1)

10 [0060] H+ produced at the anode 12 moves through the electrolytic solution existing in

the anode flow path 150 and the diaphragm 13 and reaches the vicinity of the cathode 11.

Electrons (e−) based on the current supplied from the power supply 40 to the cathode 11

and H+ moved to the vicinity of the cathode 11 cause a reduction reaction of carbon

dioxide. Specifically, carbon dioxide supplied from the cathode flow path 140 to the

15 cathode 11 is reduced to produce carbon monoxide as expressed by Formula (2) below.

Further, hydrogen ions receive electrons to produce hydrogen as in Formula (3) below. In

this event, hydrogen may be produced at the same time with carbon monoxide.

[0061] CO2 + 2H++ 2e− → CO + H2O ... (2)

[0062] 2H+ + 2e− → H2 ... (3)

20 [0063] Next, a reaction process in the case of reducing mainly carbon dioxide (CO2) to

produce hydroxide ions (OH−) will be explained. When current is supplied between the

cathode 11 and the anode 12 from the power supply, water (H2O) and carbon dioxide (CO2)

are reduced to produce carbon monoxide (CO) and hydroxide ions (OH−) near the cathode

11 as expressed by Formula (4) below. Further, water receives electrons as in Formula (5)

25 below to produce hydrogen. In this event, hydrogen may be produced at the same time

with carbon monoxide. The hydroxide ions (OH−) produced by the reactions diffuse in the

vicinity of the anode 12, whereby the hydroxide ions (OH−) are oxidized to produce

oxygen (O2) as in Formula (6) below.

[0064] 2CO2 + 2H2O + 4e− → 2CO + 4OH− ... (4)

[0065] 2H2O + 2e− → H2 + 2OH− ... (5)

[0066] 4OH− → 2H2O + O2 + 4e− ... (6)

[0067] As above, the electrolysis cell 10 is not specialized only for the reduction of

5 carbon dioxide, but can produce, for example, carbon monoxide and hydrogen at 1:2 and 2024201433

also manufacture a reduction product and hydrogen at an arbitrary ratio such as

manufacturing methanol by a chemical reaction thereafter.

[0068] Since hydrogen is a raw material inexpensive and easily available from

electrolysis of water or a fossil fuel, the percentage of hydrogen does not need to be large.

10 In view of these facts, the percentage of carbon monoxide to hydrogen is at least 1 or more,

and preferably 1.5 or more in terms of economy and environment.

[0069] Next, a reaction process in the case of reducing mainly oxygen (O2) to produce

water (H2O) will be explained. When current is supplied between the cathode 11 and the

anode 12 from the power supply, oxygen (O2) is reduced to produce water (H2O) in the

15 vicinity of the cathode 11 as expressed in Formula (7) below. In this event, water may be

produced at the same time with carbon monoxide and hydrogen, but it is considered that

reduction of oxygen mainly proceeds because of the difference in reduction potential.

Water in the electrolytic solution is oxidized to produce oxygen (O2) and protons (H+) as

expressed in Formula (8) below, and protons (H+) required for the reaction in Formula (7)

20 below diffuse from the vicinity of the anode 12. Further, hydrogen peroxide (H2O2) may

be produced as an intermediate product or a product. Conceivable oxygen reduction

reactions are two-electron reduction and four-electron reduction, and can occur in any of

acidic and alkaline environments.

[0070] O2 + 4H+ + 4e− → 2H2O ... (7)

25 [0071] 2H2O → O2 + 4H+ + 4e− ... (8)

[0072] The electrolysis cell 10 is not specialized only for the reduction of carbon dioxide,

but if impurity gases of oxygen and nitrogen are mixed, the electrolysis cell 10 can also

reduce them.

[0073] In the case of a nitrogen electrolysis device, the cathode 11 can reduce nitrogen to

produce ammonia. For the other configuration of the nitrogen electrolysis device, the

configuration of the electrolysis device 1 can be appropriately used. In this case, the

impurity gas of the cathode fluid is not nitrogen.

5 [0074] In the case where the cathode fluid contains gas of the reducible material such as 2024201433

carbon dioxide or nitrogen and gas of an impurity such as oxygen when the cathode fluid is

supplied from the cathode supply source 20 to the cell structure 100 and the electrolysis

cell 10 reduces the reducible material to produce the reduction product, current is

consumed for the reduction of the impurity gas and therefore current is accordingly

10 wastefully consumed. Further, the current for reducing the reducible material accordingly

decreases, the amount of carbon dioxide to be reduced decreases, and the Faraday

efficiency of the reduction product such as the carbon compound and ammonia may

decrease. In the conventional electrolysis device, the cathode fluid, the anode fluid, and

the power supply current are supplied to flow through the cell stack in series, and therefore

15 it is difficult to control the current supply amount of the electrolysis cell at the first stage

where the reduction of the impurity gas mainly occurs. Further, to achieve the high

electrolysis efficiency of the electrolysis device, it is necessary to make the electrolysis

device operable with low power consumption.

[0075] In contrast, the electrolysis device in the embodiment can supply a first power

20 supply current to the electrolysis cells 10 in a first group including the electrolysis cell 10

at the first stage, and supply a second power supply current to the electrolysis cells 10 in a

second group including at least one of the electrolysis cells 10 at the next and subsequent

stages. In the electrolysis device 1 illustrated in FIG. 1, a plurality of the electrolysis cells

10 are connected in parallel to the power supply 40, and thereby current can be

25 independently supplied to each of the electrolysis cells 10. Not limited to this

configuration, the first power supply current may be supplied to the electrolysis cells 10 in

the first group including the electrolysis cells 10 at the first stage to an X stage (X is a

natural number of 2 or more), and the second power supply current may be supplied to the

electrolysis cells 10 in the second group including at least one of the electrolysis cells 10 at

an X+1 and subsequent stages.

[0076] FIG. 11 is a schematic view illustrating an appearance in which an impurity such

as oxygen and a reducible material such as carbon dioxide in the cathode fluid flow in

5 series through the electrolysis cells 10. FIG. 12 is a chart illustrating examples of graphs 2024201433

indicating the relation among a current density flowing through the electrolysis cell 10, a

cell voltage, and a Faraday efficiency. A curve of a solid line illustrated in FIG. 12

indicates the relation between a cell voltage of the electrolysis cell 10 supplied with a

mixed gas containing gas of carbon dioxide and gas of oxygen and a current density of

10 current flowing through the electrolysis cell 10. A curve of a dotted line illustrated in FIG.

12 indicates the relation between a cell voltage of the electrolysis cell 10 supplied with a

single gas of carbon dioxide and a current density of current flowing through the

electrolysis cell 10. A curve of a one-dotted chain line illustrated in FIG. 12 indicates the

relation between a Faraday efficiency of carbon monoxide of the electrolysis cell 10

15 supplied with a single gas of carbon dioxide and a current density of current flowing

through the electrolysis cell 10. A curve of a two-dotted chain line illustrated in FIG. 12

indicates the relation between a Faraday efficiency of carbon monoxide of the electrolysis

cell 10 supplied with a mixed gas containing a carbon dioxide gas and an oxygen gas and a

current density of current flowing through the electrolysis cell 10.

20 [0077] In the case where the current density of current flowing through the electrolysis

cell 10 is low, current is consumed mainly for producing water by the oxygen reduction, so

that the production of carbon monoxide by the reduction of carbon dioxide does not

proceed. On the other hand, in the case where the current density of current flowing

through the electrolysis cell 10 is high, current is consumed mainly for production of

25 carbon monoxide, and the production of carbon monoxide proceeds. This can be

considered because oxygen is preferentially reduced in the vicinity of the inlet of the

cathode flow path 140 of the electrolysis cell 10, the oxygen concentration decreases, and

mainly carbon dioxide is reduced at the middle and subsequent stages in the cathode flow

path 140, resulting in a preferable environment. As illustrated in FIG. 11 and FIG. 12, the

reduction of oxygen is mainly and preferentially performed in a range (range A in FIG. 12)

of a low current density of 100 mA/cm2 or less, current is mainly consumed for the

production of water or the like by the oxygen reduction, so that the production of carbon

5 monoxide by the reduction of carbon dioxide does not proceed. Further, in a range (the 2024201433

range B in FIG. 12) of a high current density of 200 mA/cm2 or more, the reduction of

carbon dioxide is mainly and preferentially performed and current is mainly consumed for

the production of carbon monoxide by the reduction of carbon dioxide.

[0078] Hence, the first power supply current is supplied so that the current flowing

10 through the electrolysis cell 10 at the first stage (electrolysis cell 10_1) has a low current

density. The current density at this time is, for example, 1 mA/cm2 or more and 150

mA/cm2 or less. This allows the reduction of oxygen to be preferentially performed in the

electrolysis cell 10 at the first stage. As a result, almost all of the impurities in the cathode

fluid are reduced in the electrolysis cell 10 at the first stage, so that the composition of the

15 cathode fluid flowing through the electrolysis cells 10 at the next and subsequent stage is

only gas of mainly the reducible material. Here, the area of the electrolysis cell 10 at the

first stage and the area of the electrolysis cell 10 at the next or subsequent stage are the

same, but the areas of the electrolysis cells 10 do not always need to be the same. The area

of the electrolysis cell 10 includes, for example, the area of an overlapping portion of the

20 cathode 11 and the cathode flow path 140, the area of an overlapping portion of the anode

12 and the anode flow path 150, and so on.

[0079] Further, the second power supply current is supplied so that the current flowing

through the electrolysis cells 10 at the next and subsequent stages has a high current

density. The current density at this time is, for example, 150 mA/cm2 or more. The upper

25 limit of the current density is not particularly limited but is, for example, 1000 mA/cm2 or

less. Thus, more reducible material can be reduced at the electrolysis cells 10 at the next

and subsequent stages, and the composition of the cathode fluid to be supplied to the

electrolysis cells 10 at the next and subsequent stages can be composed of almost only gas

of the reducible material, so that the electrolysis cell 10 where the current is consumed for

the reduction of impurities can be limited to the electrolysis cell 10 at the first stage,

thereby making it possible to suppress the unnecessary current consumption in the

electrolytic reaction such as the reduction reaction of impurities. Thus, it is possible to

5 provide the electrolysis device operable with low power consumption. The impurity gas 2024201433

such as oxygen is sometimes supplied also to the electrolysis cells 10 at the second and

subsequent stages. In this case, in the electrolysis device in the embodiment, the power

supply current can be supplied from the power supply 40 so that the current density of the

current flowing through each of the electrolysis cells 10 in the second group including at

10 least one of the electrolysis cells 10 at the next and subsequent stages is higher than the

current density of the current flowing through each of the electrolysis cells 10 in the first

group including the electrolysis cell 10_1 at the first stage and at least one of the

electrolysis cells 10 at the second and subsequent stages. Further, the reduction potential

of a carbon dioxide gas is higher than the reduction potential of an oxygen gas as

15 illustrated in FIG. 12.

[0080] FIG. 13 is a schematic view illustrating another example of the electrolysis device

in the embodiment. FIG. 13 illustrates another configuration example of the electrolysis

device 1. The electrolysis device 1 may share one cathode current collector 16 and one

anode current collector 17 among a plurality of the stacked electrolysis cells 10 as

20 illustrated in FIG. 13. FIG. 13 illustrates an example including an electrolysis cell 10_2

and an electrolysis cell 10_3 between the one cathode current collector 16 and the one

anode current collector 17 in which the anode flow path plate 15 in the electrolysis cell

10_2 is electrically connected to the cathode flow path plate 14 in the electrolysis cell

10_3. The above configuration can decrease the numbers of the cathode current collectors

25 16 and the anode current collectors 17 and thereby can suppress the manufacturing cost

and thickness of the cell structure 100.

[0081] FIG. 14 is a schematic view illustrating another example of the electrolysis device

in the embodiment. FIG. 14 illustrates another configuration example of the electrolysis

device 1. The electrolysis device 1 may have a power supply 41 and a power supply 42 as

illustrated in FIG. 14.

[0082] The power supply 41 is electrically connected to the electrolysis cells 10 in the

first group including the electrolysis cell 10 at the first stage. The power supply 41 can

5 supply the first power supply current to the electrolysis cell 10 at the first stage. For the 2024201433

other explanation of the power supply 41, the explanation of the power supply 40 can be

appropriately used.

[0083] The power supply 42 is electrically connected to the electrolysis cells 10 in the

second group including at least one of the electrolysis cells 10 at stages next and

10 subsequent to the electrolysis cells 10 in the first group. The power supply 42 can supply

the second power supply current to the electrolysis cell 10 at the next and subsequent

stages. For the other explanation of the power supply 42, the explanation of the power

supply 40 can be appropriately used.

[0084] The values of the first power supply current and the second power supply current

15 are adjusted by the power supply 41 and the power supply 42 so that when the area of the

electrolysis cells 10 in the first group and the area of the electrolysis cells 10 in the second

group are the same, the current density of the current flowing through the electrolysis cells

10 in the second group is higher than the current density of the current flowing through the

electrolysis cells 10 in the first group. The above configuration can individually set the

20 first power supply current and the second power supply current, for example, to have

optimum current densities in accordance with the respective cell voltages of the

electrolysis cells 10 in the first group and the electrolysis cells 10 in the second group, and

supply them. In this event, if the prediction of the voltage is difficult, the optimum current

densities can be adjusted by providing a resistor between the electrolysis cells 10 in the

25 first group and the electrolysis cells 10 in the second group or connecting a current monitor

to each of the electrolysis cells 10. The current may be supplied while controlling the cell

voltage of each electrolysis cell 10. The reduction product may be selectively changed by

controlling the voltage or current of the electrolysis cells 10 in the second group. Here, the

area of the electrolysis cells 10 in the first group and the area of the electrolysis cells 10 in

the second group are the same, but the areas of a plurality of electrolysis cells do always

need to be the same. In this case, the values of the current density of the first power supply

current and the current density of the second power supply current are adjusted by the

5 power supply 41 and the power supply 42 so that the current density of current flowing 2024201433

through the electrolysis cells 10 in the second group is higher than the current density of

current flowing through the electrolysis cells 10 in the first group.

[0085] FIG. 15 is a schematic view illustrating another example of the electrolysis device

in the embodiment. FIG. 15 illustrates another configuration example of the electrolysis

10 device 1. As illustrated in FIG. 15, the electrolysis device 1 may have a power supply 41, a

power supply 42, a pipe 19a for separating the electrolysis cells 10 in the first group and

the electrolysis cells 10 in the second group and supplying the cathode fluid from the

electrolysis cells 10 in the first group to the electrolysis cells 10 in the second group, and a

pipe 19b for supplying the anode fluid from the electrolysis cells 10 in the first group to the

15 electrolysis cells 10 in the second group.

[0086] The pipe 19a connects the cathode flow path 140 of the electrolysis cell 10 at the

final stage in the first group and the cathode flow path 140 of the electrolysis cell 10 at the

initial stage in the second group. The pipe 19b connects the anode flow path 150 of the

electrolysis cell 10 at the final stage in the first group and the anode flow path 150 of the

20 electrolysis cell 10 at the initial stage in the second group. The pipe 19a and the pipe 19b

can be formed using, for example, a metal material or an insulating material. The above

configuration can keep a distance between the electrolysis cells 10 in the first group and

the electrolysis cells 10 in the second group. This can efficiently utilize, for example, even

a small installation space.

25 [0087] FIG. 16 is a schematic view illustrating another example of the electrolysis device

in the embodiment. FIG. 16 illustrates another configuration example of the electrolysis

device 1. As illustrated in FIG. 16, the electrolysis device 1 may have a power supply 41

and a power supply 42, supply the cathode fluid from the cathode supply source 20 to flow

in parallel through the electrolysis cells 10, and supply the anode fluid from the anode

supply source 30 to flow in parallel through the stacked electrolysis cells 10. The cathode

flow paths 140 of the electrolysis cells 10 in the first group and the cathode flow paths 140

of the electrolysis cells 10 in the second group may be connected, for example, in parallel.

5 The anode flow paths 150 of the electrolysis cells 10 in the first group and the anode flow 2024201433

paths 150 of the electrolysis cells 10 in the second group may be connected, for example,

in parallel. The above configuration can individually set optimum current and gas

composition and its gas flow rate in accordance with the respective cell voltages of the

10 make them flow. In this event, in the case where the prediction of voltage is difficult, the

optimum current density can be adjusted by providing a resistor between the electrolysis

cells 10 in the first group and the electrolysis cells 10 in the second group or connecting a

current monitor to each of the electrolysis cells 10. The current may be supplied while

controlling the cell voltage of each electrolysis cell 10. The reduction product may be

15 selectively changed by controlling the voltage or current of the electrolysis cells 10 in the

second group.

[0088] When the cathode fluid contains a first gas of the reducible material and a second

gas of an impurity and the second gas is nitrogen, the electrolysis cells 10 in the first group

reduce nitrogen to produce ammonia, and the electrolysis cells 10 in the second group

20 reduce the reducible material such as carbon dioxide to produce a reduction product such

as a carbon compound.

[0089] The cathodes 11 in the electrolysis cells 10 in the first group may have a first

catalyst and the cathodes 11 in the electrolysis cells 10 in the second group may have a

second catalyst. The first catalyst is different from the second catalyst. Examples of the

25 first catalyst include platinum and its alloy. Examples of the second catalyst include gold.

The selection of an optimum catalyst according to a main product for each electrolysis cell

10 can improve the electrolysis efficiency of the electrolysis device.

[0090] The electrolysis device 1 may be employed, for example, for an electrolysis

system. The electrolysis system may further include a control device. The control device

can control, for example, the power supply voltages or the power supply currents from the

power supply 40. Further, the control device can control, for example, the flow rate of the

cathode fluid from the cathode supply source 20. Further, the control device can control,

5 for example, the flow rate of the anode fluid from the anode supply source 30. The control 2024201433

device has, for example, hardware having an arithmetic unit such as a processor. Each

operation may be held as an operating program on a computer-readable recording medium

such as a memory and each operation may be executed by appropriately reading the

operation program stored on the recording medium by the hardware.

10 [0091] The above configuration examples of the electrolysis device 1 can be arbitrarily

combined.

[0092] The configurations of the above-described embodiments are applicable in

combination. Further, parts thereof are replaceable. While certain embodiments of the

present invention have been described above, these embodiments have been presented by

15 way of example only, and are not intended to limit the scope of the invention. Indeed, the

novel embodiments described herein may be embodied in a variety of other forms;

furthermore, various omissions, substitutions, and changes in the form of the embodiments

described herein may be made without departing from the scope of the inventions. The

accompanying claims and their equivalents are intended to cover such forms or

20 modifications as would fall within the scope of the inventions.

[0093] It is to be understood that, if any prior art publication is referred to herein, such

reference does not constitute an admission that the publication forms a part of the common

general knowledge in the art, in Australia or any other country.

[0094] In the claims which follow and in the preceding description of the invention,

25 except where the context requires otherwise due to express language or necessary

implication, the word “comprise” or variations such as “comprises” or “comprising” is

used in an inclusive sense, i.e. to specify the presence of the stated features but not to

preclude the presence or addition of further features in various embodiments of the

invention.

[0095] The above embodiments can be summarized in the following clauses.

(Clause 1)

An electrolysis device comprising:

5 a first electrolysis cell configured to reduce a reducible material and to oxidize an 2024201433

oxidizable material;

a second electrolysis cell configured to reduce the reducible material and to

oxidize the oxidizable material;

a first supply source configured to supply a first fluid to the first electrolysis cell

10 and the second electrolysis cell, the first fluid containing a gas of the reducible material;

a second supply source configured to supply a second fluid to the first electrolysis

cell and the second electrolysis cell, the second fluid containing a liquid of the oxidizable

material; and

at least one power supply configured to supply a first power supply current to the

15 first electrolysis cell and to supply a second power supply current to the second electrolysis

cell, wherein

the at least one power supply is configured to set a value of the first power supply

current and a value of the second power supply current so that a current density of current

flowing through the second electrolysis cell when reducing the reducible material is higher

20 than a current density of current flowing through the first electrolysis cell when reducing

the reducible material.

(Clause 2)

The electrolysis device according to clause 1, wherein:

the first electrolysis cell has:

25 a first membrane electrode assembly having a first cathode, a first anode,

and a first diaphragm between the first cathode and the first anode;

a first cathode flow path plate having a first cathode flow path facing on

the first cathode; and

a first anode flow path plate having a first anode flow path facing on the

first anode;

the second electrolysis cell has:

a second membrane electrode assembly having a second cathode, a

5 second anode, and a second diaphragm between the second cathode and the second anode; 2024201433

a second cathode flow path plate having a second cathode flow path

facing on the second cathode; and

a second anode flow path plate having a second anode flow path facing

on the second anode; and

10 the device further comprises:

a first cathode current collector electrically connected to the first cathode and the

at least one power supply;

a first anode current collector electrically connected to the first anode and the at

least one power supply;

15 a second cathode current collector electrically connected to the second cathode

and the at least one power supply; and

a second anode current collector electrically connected to the second anode and

the at least one power supply.

(Clause 3)

20 The device according to clause 2, wherein

the second cathode flow path is connected in series to the first cathode flow path.

(Clause 4)

The device according to clause 2, wherein

the second cathode flow path is connected in parallel to the first cathode flow

25 path.

(Clause 5)

The device according to any one of clause 2 to clause 4, wherein:

the at least one power supply includes a power supply configured to supply the

first power supply current to the first electrolysis cell via the first cathode current collector

and the first anode current collector and supply the second power supply current to the

second electrolysis cell via the second cathode current collector and the second anode

current collector; and

5 the first cathode current collector, the first anode current collector, the second 2024201433

cathode current collector, and the second anode current collector are electrically connected

to the power supply.

(Clause 6)

The device according to any one of clause 2 to clause 4, wherein

10 the at least one power supply includes:

a first power supply configured to supply the first power supply current to the first

electrolysis cell via the first cathode current collector and the first anode current collector;

and

a second power supply configured to supply the second power supply current to

15 the second electrolysis cell via the second cathode current collector and the second anode

current collector.

(Clause 7)

The device according to any one of clause 1 to clause 6, wherein:

the first fluid contains a first gas and a second gas;

20 the first gas is gas of carbon dioxide;

the second gas is gas of a substance different from the carbon dioxide;

the first electrolysis cell and the second electrolysis cell reduce the carbon dioxide

and reduce the substance; and

a reduction potential of the carbon dioxide is higher than a reduction potential of

25 the substance.

(Clause 8)

The device according to clause 7, wherein

the substance is oxygen.

(Clause 9)

The device according to clause 7, wherein

the substance is nitrogen.

(Clause 10)

5 The device according to any of clause 7 to clause 9, wherein 2024201433

a concentration of the second gas of the first fluid is 1 ppm or higher and 100000

ppm or lower.

(Clause 11)

The device according to any one of clause 2 to clause 6, further comprising

10 a third electrolysis cell between the second cathode current collector and the

second anode current collector, wherein

the third electrolysis cell having

a third cathode;

a third anode;

15 a third diaphragm between the third cathode and the third anode;

a third cathode flow path plate having a third cathode flow path facing on

the third cathode; and

a fourth anode flow path plate having a third anode flow path facing on

the third anode; and

20 the third cathode is electrically connected to the second anode, or the third anode

is electrically connected to the second cathode.

(Clause 12)

The device according to any one of clause 2 to clause 7, comprising:

a first pipe configured to connect the first electrolysis cell and the second

25 electrolysis cell, and supply the first fluid from the first cathode flow path to the second

cathode flow path; and

a second pipe configured to connect the first electrolysis cell and the second

electrolysis cell, and supply the second fluid from the first anode flow path to the second

anode flow path.

(Clause 13)

The device according to any one of clause 2 to clause 6 and clause 12, wherein

the first cathode has a first catalyst;

5 the second cathode has a second catalyst; and 2024201433

the first catalyst is different from the second catalyst.

(Clause 14)

The device according to any one of clause 2 to clause 6, clause 12, and clause 13,

wherein:

10 the first fluid contains gas of carbon dioxide;

the first electrolysis cell is configured to reduce carbon dioxide by the first

cathode to produce a carbon compound; and

the second electrolysis cell is configured to reduce the carbon dioxide by the

second cathode to produce the carbon compound.

15 (Clause 15)

wherein

the first fluid contains a gas of nitrogen;

the first electrolysis cell is configured to reduce nitrogen by the first cathode to

20 produce ammonia; and

the second electrolysis cell is configured to reduce the nitrogen by the second

cathode to produce the ammonia.

(Clause 16)

The device according to any one of clause 2 to clause 6 and clause 12 to clause 15,

25 wherein

the first electrolysis cell comprises:

a first membrane electrode assembly having the first cathode, the first

anode, and the first diaphragm;

a first supporting plate surrounding the first membrane electrode

assembly and having a first opening and a second opening;

a first cathode flow path plate having the first cathode flow path

connected to the first opening, a third opening connected to the first cathode flow path, and

5 a fourth opening connected to the second opening; 2024201433

a first anode flow path plate having the first anode flow path connected to

the second opening, a fifth opening connected to the first opening, and a sixth opening

connected to the first anode flow path;

the first cathode current collector having a seventh opening connected to

10 the third opening and an eighth opening connected to the fourth opening; and

the first anode current collector having a ninth opening connected to the

fifth opening and a tenth opening connected to the sixth opening; and

the second electrolysis cell comprises:

a second membrane electrode assembly having the second cathode, the

15 second anode, and the second diaphragm;

a second supporting plate surrounding the second membrane electrode

assembly and having an eleventh opening and a twelfth opening;

a second cathode flow path plate having the second cathode flow path

connected to the eleventh opening, a thirteenth opening connected to the second cathode

20 flow path, and a fourteenth opening connected to the twelfth opening;

a second anode flow path plate having the second anode flow path

connected to the twelfth opening, a fifteenth opening connected to the eleventh opening,

and a sixteenth opening connected to the second anode flow path;

the second cathode current collector having a seventeenth opening

25 connected to the thirteenth opening and an eighteenth opening connected to the fourteenth

opening; and

the second anode current collector having a nineteenth opening connected

to the fifteenth opening and a twentieth opening connected to the sixteenth opening.

(Clause 17)

The device according to clause 16, further comprising

an insulating layer provided between the first electrolysis cell and the second

electrolysis cell and having a twenty-first opening connecting the ninth opening and the

5 fourteenth opening, and a twenty-second opening connecting the tenth opening and the 2024201433

thirteenth opening.

(Clause 18)

An electrolysis system comprising the device according to any one of clause 1 to

clause 17.

10 (Clause 19)

A method of operating an electrolysis device,

the device comprising:

a first electrolysis cell configured to reduce a reducible material and to

oxidize an oxidizable material;

15 a second electrolysis cell configured to reduce the reducible material and

to oxidize the oxidizable material;

a first supply source configured to supply a first fluid to the first

electrolysis cell and the second electrolysis cell, the first fluid containing a gas of the

reducible material;

20 a second supply source configured to supply a second fluid to the first

electrolysis cell and the second electrolysis cell, the second fluid containing a liquid of the

oxidizable material; and

at least one power supply configured to supply a first power supply

current to the first electrolysis cell and to supply a second power supply current to the

25 second electrolysis cell,

the method comprising:

supplying the first fluid to the first electrolysis cell and the second electrolysis

cell, and supplying the second fluid to the first electrolysis cell and the second electrolysis

cell; and

supplying the first power supply current to the first electrolysis cell to reduce the

reducible material, and supplying the second power supply current to the second

electrolysis cell to reduce the reducible material, wherein

5 a current density of a current flowing through the second electrolysis cell when 2024201433

reducing the reducible material is higher than a current density of a current flowing

through the first electrolysis cell when reducing the reducible material.

(Clause 20)

The method according to clause 19, wherein

10 the first fluid contains a gas of carbon dioxide or a gas of nitrogen.

[0096] Throughout this specification and the claims which follow, unless the context

requires otherwise, the word "comprise", and variations such as "comprises" and

"comprising", will be understood to imply the inclusion of a stated integer or step or group

of integers or steps but not the exclusion of any other integer or step or group of integers or

15 steps.

[0097] The reference in this specification to any prior publication (or information derived

from it), or to any matter which is known, is not, and should not be taken as an

acknowledgment or admission or any form of suggestion that that prior publication (or

information derived from it) or known matter forms part of the common general

20 knowledge in the field of endeavour to which this specification relates.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An electrolysis device, comprising:

a first electrolysis cell configured to reduce a reducible material and to oxidize an

5 oxidizable material; 2024201433

a second electrolysis cell configured to reduce the reducible material and to

oxidize the oxidizable material;

and the second electrolysis cell, the first fluid containing a gas of the reducible material;

10 a second supply source configured to supply a second fluid to the first electrolysis

material; and

first electrolysis cell and to supply a second power supply current to the second electrolysis

15 cell, wherein

than a current density of current flowing through the first electrolysis cell when reducing

20 the reducible material, wherein:

the first electrolysis cell has:

a first membrane electrode assembly having a first cathode, a first anode,

and a first diaphragm between the first cathode and the first anode;

a first cathode flow path plate having a first cathode flow path facing on

25 the first cathode; and

a first anode flow path plate having a first anode flow path facing on the

first anode;

the second electrolysis cell has:

a second membrane electrode assembly having a second cathode, a

second anode, and a second diaphragm between the second cathode and the second anode;

a second cathode flow path plate having a second cathode flow path

facing on the second cathode; and

5 a second anode flow path plate having a second anode flow path facing 2024201433

on the second anode, and

the device further comprises:

at least one power supply;

10 a first anode current collector electrically connected to the first anode and the at

least one power supply;

a second cathode current collector electrically connected to the second cathode

and the at least one power supply; and

a second anode current collector electrically connected to the second anode and

15 the at least one power supply.

2. The device according to claim 1, wherein

20

3. The device according to claim 1, wherein

the second cathode flow path is connected in parallel to the first cathode flow

path.

4. The device according to any one of claim 1 to claim 3, wherein:

25 the at least one power supply includes a power supply configured to supply the

current collector; and

the first cathode current collector, the first anode current collector, the second

5 to the power supply. 2024201433

5. The device according to any one of claim 1 to claim 3, wherein

the at least one power supply includes:

10 electrolysis cell via the first cathode current collector and the first anode current collector;

and

a second power supply configured to supply the second power supply current to

the second electrolysis cell via the second cathode current collector and the second anode

current collector.

15

6. The device according to any one of claim 1 to claim 5, wherein:

the first fluid contains a first gas and a second gas;

the first gas is gas of carbon dioxide;

the second gas is gas of a substance different from the carbon dioxide;

20 the first electrolysis cell and the second electrolysis cell reduce the carbon dioxide

and reduce the substance; and

the substance.

25

7. The device according to claim 6, wherein

the substance is oxygen.

8. The device according to claim 6, wherein

the substance is nitrogen.

9. The device according to any one of claim 6 to claim 8, wherein

5 ppm or lower. 2024201433

10. The device according to any one of claim 1 to claim 5, further comprising

a third electrolysis cell between the second cathode current collector and the

second anode current collector, wherein

10 the third electrolysis cell having

a third cathode;

a third anode;

a third diaphragm between the third cathode and the third anode;

a third cathode flow path plate having a third cathode flow path facing on

15 the third cathode; and

a fourth anode flow path plate having a third anode flow path facing on

the third anode; and

the third cathode is electrically connected to the second anode, or the third anode

is electrically connected to the second cathode.

20

11. The device according to any one of claim 1 to claim 6, further comprising:

a first pipe configured to connect the first electrolysis cell and the second

electrolysis cell, and supply the first fluid from the first cathode flow path to the second

cathode flow path; and

25 a second pipe configured to connect the first electrolysis cell and the second

anode flow path.

12. The device according to any one of claim 1 to claim 5 and claim 11, wherein

the first cathode has a first catalyst;

the second cathode has a second catalyst; and

the first catalyst is different from the second catalyst.

5 2024201433

13. The device according to any one of claim 1 to claim 5 and claim 11, wherein:

the first fluid contains gas of carbon dioxide;

the first electrolysis cell is configured to reduce carbon dioxide by the first

cathode to produce a carbon compound; and

10 the second electrolysis cell is configured to reduce the carbon dioxide by the

second cathode to produce the carbon compound.

14. The device according to any one of claim 1 to claim 5 and claim 11, wherein

the first fluid contains a gas of nitrogen;

15 the first electrolysis cell is configured to reduce nitrogen by the first cathode to

produce ammonia; and

the second electrolysis cell is configured to reduce the nitrogen by the second

cathode to produce the ammonia.

20 15. The device according to any one of claim 1 to claim 5 and claim 11, wherein

the first electrolysis cell comprises:

a first membrane electrode assembly having the first cathode, the first

anode, and the first diaphragm;

a first supporting plate surrounding the first membrane electrode

25 assembly and having a first opening and a second opening;

a first cathode flow path plate having the first cathode flow path

a fourth opening connected to the second opening;

a first anode flow path plate having the first anode flow path connected to

connected to the first anode flow path;

the first cathode current collector having a seventh opening connected to

5 the third opening and an eighth opening connected to the fourth opening; and 2024201433

the first anode current collector having a ninth opening connected to the

fifth opening and a tenth opening connected to the sixth opening; and

the second electrolysis cell comprises:

a second membrane electrode assembly having the second cathode, the

10 second anode, and the second diaphragm;

a second supporting plate surrounding the second membrane electrode

assembly and having an eleventh opening and a twelfth opening;

a second cathode flow path plate having the second cathode flow path

15 flow path, and a fourteenth opening connected to the twelfth opening;

a second anode flow path plate having the second anode flow path

and a sixteenth opening connected to the second anode flow path;

the second cathode current collector having a seventeenth opening

20 connected to the thirteenth opening and an eighteenth opening connected to the fourteenth

opening; and

the second anode current collector having a nineteenth opening connected

25

16. The device according to claim 15, further comprising

an insulating layer provided between the first electrolysis cell and the second

fourteenth opening, and a twenty-second opening connecting the tenth opening and the

thirteenth opening.

17. An electrolysis system comprising the device according to any one of claim 1

5 to claim 16. 2024201433

18. A method of operating an electrolysis device,

the device comprising:

a first electrolysis cell configured to reduce a reducible material and to

10 oxidize an oxidizable material;

a second electrolysis cell configured to reduce the reducible material and

to oxidize the oxidizable material;

a first supply source configured to supply a first fluid to the first

15 reducible material;

a second supply source configured to supply a second fluid to the first

oxidizable material; and

at least one power supply configured to supply a first power supply

20 current to the first electrolysis cell and to supply a second power supply current to the

second electrolysis cell, wherein:

the first electrolysis cell has:

a first membrane electrode assembly having a first cathode, a first anode,

and a first diaphragm between the first cathode and the first anode;

25 a first cathode flow path plate having a first cathode flow path facing on

the first cathode; and

a first anode flow path plate having a first anode flow path facing on the

first anode;

the second electrolysis cell has:

a second membrane electrode assembly having a second cathode, a

a second cathode flow path plate having a second cathode flow path

5 facing on the second cathode; and 2024201433

a second anode flow path plate having a second anode flow path facing

on the second anode, and

the device further comprises:

10 at least one power supply;

least one power supply;

a second cathode current collector electrically connected to the second cathode

and the at least one power supply; and

15 a second anode current collector electrically connected to the second anode and

the at least one power supply,

the method comprising:

20 cell; and

reducible material, and supplying the second power supply current to the second

electrolysis cell to reduce the reducible material, wherein

a current density of a current flowing through the second electrolysis cell when

25 reducing the reducible material is higher than a current density of a current flowing

through the first electrolysis cell when reducing the reducible material.

19. The method according to claim 18, wherein

the first fluid contains a gas of carbon dioxide or a gas of nitrogen. 2024201433