WO2024009857A1 - Electrochemical cell and method for producing same - Google Patents

Electrochemical cell and method for producing same Download PDF

Info

Publication number
WO2024009857A1
WO2024009857A1 PCT/JP2023/023891 JP2023023891W WO2024009857A1 WO 2024009857 A1 WO2024009857 A1 WO 2024009857A1 JP 2023023891 W JP2023023891 W JP 2023023891W WO 2024009857 A1 WO2024009857 A1 WO 2024009857A1
Authority
WO
WIPO (PCT)
Prior art keywords
working electrode
counter electrode
electrochemical cell
polymer resin
electrode
Prior art date
Application number
PCT/JP2023/023891
Other languages
French (fr)
Japanese (ja)
Inventor
裕規 辰巳
信彦 松田
翔太 木下
篤人 太田
Original Assignee
株式会社デンソー
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社デンソー filed Critical 株式会社デンソー
Publication of WO2024009857A1 publication Critical patent/WO2024009857A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/32—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by electrical effects other than those provided for in group B01D61/00
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/50—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features

Definitions

  • the present disclosure relates to an electrochemical cell and a method of manufacturing the same.
  • Patent Document 1 proposes an electrochemical cell used in a carbon dioxide recovery system that separates carbon dioxide (CO 2 ) from a gas containing carbon dioxide (CO 2 ) by an electrochemical reaction.
  • an electrochemical reaction in which CO 3 2- is generated from CO 2 by supplying a carbon dioxide-containing gas to the cathode while applying a potential difference between the cathode and the anode of an electrochemical cell;
  • An electrochemical reaction occurs in which CO 2 is produced from CO 3 2- .
  • a cathode and an anode are constructed by bonding an electrode film to a current collector, which is a porous conductive member.
  • the electrode film is configured to contain a binder in addition to the active material and the conductive additive.
  • the binder is a binding agent that assists in binding a current collector, an active material, a conductive agent, and the like.
  • PVDF polyvinylidene fluoride
  • the present disclosure aims to provide an electrochemical cell that can improve electrode performance and a method for manufacturing the same.
  • an electrochemical cell includes a working electrode that adsorbs and desorbs the recovered gas from a mixed gas containing the recovered gas through an electrochemical reaction;
  • a counter electrode that transfers electrons to and from the working electrode,
  • the electrode film constituting at least one of the working electrode and the counter electrode has an active material, a conductive aid, and a binder,
  • the binder contains a polymer resin,
  • the polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen.
  • the polymer resin contained in the binder that forms the electrode film is composed of carbon and halogen elements, or is composed of carbon, halogen elements and oxygen, the components contained in the mixed gas Decomposition of the binder can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
  • a method for manufacturing an electrochemical cell includes a working electrode that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction; A counter electrode that transfers electrons to and from the working electrode, The working electrode constituent material that constitutes the electrode film of the working electrode contains a polymer resin,
  • a method for manufacturing an electrochemical cell in which the polymer resin is composed of carbon and halogen elements, or carbon, halogen elements and oxygen including a working electrode forming step of forming a working electrode,
  • the working electrode forming process is a mixing step of mixing working electrode constituent materials;
  • the method includes a heating step of heating the working electrode constituent materials mixed in the mixing step to the thermal decomposition temperature of the polymer resin.
  • the polymer resin contained in the working electrode constituent material is composed of carbon and halogen elements, or carbon, halogen elements and oxygen, the polymer resin is decomposed by the components contained in the mixed gas. This can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
  • a method for manufacturing an electrochemical cell includes a working electrode that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction; A counter electrode that transfers electrons to and from the working electrode, The counter electrode constituent material that constitutes the counter electrode film contains a polymer resin,
  • the polymer resin is composed of carbon and halogen elements, or carbon, halogen elements and oxygen, including a counter electrode forming step of forming a counter electrode
  • the counter electrode forming process is a mixing step of mixing counter electrode constituent materials;
  • the method includes a compression step of compressing the counter electrode constituent materials mixed in the mixing step.
  • the polymer resin contained in the counter electrode constituent material is composed of carbon and halogen elements, or carbon, halogen elements and oxygen, the polymer resin is decomposed by the components contained in the mixed gas. can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
  • FIG. 1 is a conceptual diagram showing the overall configuration of a carbon dioxide recovery system in a first embodiment. It is an explanatory view showing a carbon dioxide recovery device in a 1st embodiment.
  • FIG. 1 is a cross-sectional view showing an electrochemical cell in a first embodiment.
  • FIG. 3 is a diagram showing a polymer resin contained in a working electrode side binder. It is a figure showing the relationship between the number of cycles and the amount of decomposition products with respect to the amount of carbon dioxide adsorption.
  • FIG. 3 is an explanatory diagram for explaining oxidative decomposition of PVDF in Comparative Example 1. It is a figure showing the surface of the working electrode side electrode film in a 1st embodiment.
  • FIG. 3 is a diagram showing the membrane structure of the working electrode side electrode membrane in the first embodiment.
  • 3 is a diagram showing the surface of a working electrode side electrode film in Comparative Example 2.
  • FIG. 3 is a diagram showing the membrane structure of a working electrode side electrode membrane in Comparative Example 2.
  • the carbon dioxide recovery system 10 of this embodiment is provided with a compressor 11, a carbon dioxide recovery device 100, a flow path switching valve 12, a carbon dioxide utilization device 13, and a control device 14.
  • Compressor 11 pumps carbon dioxide-containing gas to carbon dioxide recovery device 100 .
  • the carbon dioxide-containing gas is a mixed gas containing carbon dioxide and a gas other than carbon dioxide, and for example, the atmosphere can be used.
  • the carbon dioxide-containing gas contains at least oxygen (O 2 ) as a gas other than carbon dioxide.
  • the carbon dioxide recovery device 100 is a device that separates and recovers carbon dioxide from a carbon dioxide-containing gas.
  • the carbon dioxide recovery device 100 discharges carbon dioxide removed gas after carbon dioxide has been recovered from the carbon dioxide-containing gas, or carbon dioxide recovered from the carbon dioxide-containing gas.
  • the configuration of carbon dioxide recovery device 100 will be described in detail later.
  • the flow path switching valve 12 is a three-way valve that switches the flow path of the exhaust gas of the carbon dioxide recovery device 100.
  • the flow path switching valve 12 switches the flow path of the exhaust gas to the atmosphere side when carbon dioxide removal gas is discharged from the carbon dioxide recovery device 100, and switches the flow path of the exhaust gas to the atmosphere side when carbon dioxide is discharged from the carbon dioxide recovery device 100.
  • the exhaust gas flow path is switched to the carbon dioxide utilization device 13 side.
  • the carbon dioxide utilization device 13 is a device that utilizes carbon dioxide.
  • a storage tank that stores carbon dioxide or a conversion device that converts carbon dioxide into fuel can be used.
  • a conversion device a device that converts carbon dioxide into hydrocarbon fuel such as methane can be used.
  • the hydrocarbon fuel may be a gaseous fuel at normal temperature and normal pressure, or may be a liquid fuel at normal temperature and normal pressure.
  • the control device 14 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits.
  • the control device 14 performs various calculations and processes based on a control program stored in the ROM, and controls the operations of various devices to be controlled.
  • the control device 14 of this embodiment performs operation control of the compressor 11, operation control of the carbon dioxide recovery device 100, flow path switching control of the flow path switching valve 12, and the like.
  • Electrochemical cell 101 has a working electrode 130, a counter electrode 140, and a separator 150.
  • the working electrode 130, the counter electrode 140, and the separator 150 are each formed into a plate shape.
  • the working electrode 130, the counter electrode 140, and the separator 150 are shown spaced apart from each other in FIG. 2, these components are actually arranged so as to be in contact with each other.
  • the electrochemical cell 101 may be housed in a container (not shown).
  • the container can be provided with a gas inlet that allows the carbon dioxide-containing gas to flow into the container, and a gas outlet that allows the carbon dioxide removal gas and carbon dioxide to flow out of the container.
  • the carbon dioxide recovery device 100 adsorbs and desorbs carbon dioxide through an electrochemical reaction, and separates and recovers carbon dioxide from a carbon dioxide-containing gas.
  • the carbon dioxide recovery device 100 is provided with a control power source 120 that applies a predetermined voltage to the working electrode 130 and the counter electrode 140, and can change the potential difference between the working electrode 130 and the counter electrode 140.
  • Working electrode 130 is a negative electrode
  • counter electrode 140 is a positive electrode.
  • the electrochemical cell 101 operates by changing the potential difference between the working electrode 130 and the counter electrode 140 to switch between a recovery mode in which carbon dioxide is recovered at the working electrode 130 and a release mode in which carbon dioxide is released from the working electrode 130. Can be done.
  • the recovery mode is a charging mode in which the electrochemical cell 101 is charged
  • the discharge mode is a discharging mode in which the electrochemical cell 101 is discharged.
  • the first voltage V1 is applied between the working electrode 130 and the counter electrode 140, and electrons are supplied from the counter electrode 140 to the working electrode 130.
  • working electrode potential At the first voltage V1, working electrode potential ⁇ counter electrode potential.
  • the first voltage V1 can be within a range of 0.5 to 2.0V, for example.
  • a second voltage V2 lower than the first voltage V1 is applied between the working electrode 130 and the counter electrode 140, and electrons are supplied from the working electrode 130 to the counter electrode 140.
  • the second voltage V2 only needs to be a voltage lower than the first voltage V1, and the magnitude relationship between the working electrode potential and the counter electrode potential is not limited. That is, in the release mode, the working electrode potential may be less than the counter electrode potential, the working electrode potential may be equal to the counter electrode potential, or the working electrode potential may be greater than the counter electrode potential.
  • the working electrode 130 in the electrochemical cell 101 has a working electrode side current collector 131 and a working electrode side electrode film 132.
  • the working electrode side current collector 131 is connected to the control power source 120 and is a porous conductive member through which carbon dioxide-containing gas can pass.
  • the working electrode side current collector 131 for example, a carbonaceous material or a metal material can be used.
  • a carbonaceous material constituting the working electrode side current collector 131 for example, carbon paper, carbon cloth, nonwoven carbon mat, porous gas diffusion layer (GDL), etc. can be used.
  • GDL porous gas diffusion layer
  • the metal material constituting the working electrode side current collector 131 a structure made of a metal such as Al, Ni, or SUS in a mesh shape can be used, for example.
  • the working electrode side electrode film 132 adsorbs and desorbs carbon dioxide from a carbon dioxide-containing gas through an electrochemical reaction.
  • the working electrode side electrode film 132 includes a carbon dioxide adsorbent, a working electrode side conductive agent, and a working electrode side binder.
  • the working electrode side binder will be explained in detail later.
  • a carbon dioxide adsorbent is an electroactive species (i.e., an active material) that adsorbs carbon dioxide by receiving electrons and desorbs the adsorbed carbon dioxide by releasing electrons.
  • an electroactive species i.e., an active material
  • carbon dioxide adsorbent for example, carbon materials, metal oxides, polyanthraquinone, etc. can be used.
  • the working electrode side conductive agent is a conductive material that forms a conductive path to the carbon dioxide adsorbent.
  • carbon materials such as carbon nanotubes, carbon black, and graphene can be used, for example.
  • the counter electrode 140 has a counter electrode current collector 141 and a counter electrode film 142.
  • the counter electrode current collector 141 is a conductive member connected to the control power source 120.
  • the counter electrode side current collector material 141 may be made of the same material as the working electrode side current collector material 131, or may be made of a different material.
  • the counter electrode film 142 exchanges electrons with the working electrode film 132.
  • the counter electrode film includes a counter active material, a counter conductive agent, and a counter binder. The opposite binder will be described in detail later.
  • the counter electrode active material is an auxiliary electroactive species that exchanges electrons with the carbon dioxide adsorbent.
  • the counter electrode side active material is a material that can transfer electrons in and out by changing the valence of the metal and transferring charges to and from the ⁇ electron cloud.
  • a metal complex that enables transfer of electrons by changing the valence of metal ions can be used.
  • the metal complex include cyclopentadienyl metal complexes such as ferrocene, nickelocene, and cobaltocene, and porphyrin metal complexes.
  • a compound having a ferrocene skeleton is used as the counter electrode side active material.
  • PVFc polyvinylferrocene
  • ferrocene which is polymerized ferrocene
  • the counter electrode conductive aid is a conductive material that forms a conductive path to the counter electrode active material.
  • the counter-electrode conductive additive is used in combination with the counter-electrode active material.
  • the counter electrode side conductive agent may be made of the same material as the working electrode side conductive agent, or may be made of a different material.
  • the counter electrode side conductive aid is, for example, in the form of particles.
  • the separator 150 is arranged between the working electrode film 132 and the counter electrode film 142.
  • the separator 150 separates the working electrode film 132 and the counter electrode film 142. That is, the separator 150 prevents physical contact between the working electrode film 132 and the counter electrode film 142. Moreover, the separator 150 suppresses electrical short circuit between the working electrode side electrode film 132 and the counter electrode side electrode film 142.
  • separator 150 a separator made of a cellulose membrane, a polymer, a composite material of polymer and ceramic, etc. can be used.
  • separator 150 a porous separator may be used.
  • An ion conductive member is provided between the working electrode membrane 132 and the separator 150 and between the counter electrode membrane 142 and the separator 150.
  • the ion conductive member facilitates electrical conduction to the carbon dioxide adsorbent.
  • an electrolytic solution is provided as the ion conductive member. More specifically, an ionic liquid is used as the electrolyte. Ionic liquids are liquid salts that are nonvolatile at room temperature and pressure.
  • the working electrode binder and the counter electrode side binder are holding materials that have adhesive strength.
  • the working electrode side binder holds the carbon dioxide adsorbent and the working electrode side conductive agent on the working electrode side current collector 131. Specifically, a mixture of a carbon dioxide adsorbent, a conductive agent on the working electrode side, and a binder on the working electrode side is formed, and the mixture is adhered to the current collector 131 on the working electrode side. The carbon dioxide adsorbent and the working electrode side conductive agent are held inside the working electrode side binder.
  • the working electrode side binder contains a polymer resin.
  • the polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen. That is, the working electrode side binder contains a polymer resin that does not contain hydrogen element (H).
  • FIG. 4 illustrates the polymer resin contained in the working electrode side binder of this embodiment.
  • the polymer resin includes at least one of PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene/hexafluoropropylene copolymer), PCTFE (polychlorotrifluoroethylene), and PFA (perfluoroalkoxyalkane). Contains.
  • the counter-electrode binder is a material that can hold the counter-electrode active material and the counter-electrode conductive aid on the counter-electrode current collector 141 and has electrical conductivity.
  • the binder on the opposite electrode side may be made of the same material as the binder on the working electrode side, or may be made of a different material. In this embodiment, PVDF is used as the opposite binder.
  • a working electrode side mixing step is performed in which working electrode constituent materials, which are the materials forming the working electrode side electrode film 132, are mixed.
  • the working electrode constituent material includes a carbon dioxide adsorbent, a working electrode side conductive agent, and a working electrode side binder.
  • a metal oxide is used as a carbon dioxide adsorbent
  • a carbon material is used as a conductive agent on the working electrode side
  • PTFE which is a polymer resin
  • the working electrode constituent materials are dispersed and mixed using a homogenizer or the like, and then dissolved in a solvent (that is, an organic solvent) to produce a mixture.
  • a solvent that is, an organic solvent
  • PTFE which is a binder on the working electrode side
  • NMP N-methylpyrrolidone
  • a heating step is performed in which the mixed working electrode constituent materials are heated to the thermal decomposition temperature of PTFE.
  • the mixed working electrode constituent materials are applied to the working electrode side current collector material 131 and then fired at 350°C.
  • the working electrode side electrode film 132 is formed on the surface of the working electrode side current collector material 131. In this way, the working electrode forming step is completed.
  • the present inventors investigated the amount of decomposition products relative to the amount of carbon dioxide adsorbed in carbon dioxide recovery using the electrochemical cell 101 including the working electrode 130 obtained in the above working electrode forming step. Specifically, the combination of the recovery mode and the release mode was defined as one cycle, and the amount of decomposition products relative to the amount of carbon dioxide adsorption in each cycle was measured.
  • the amount of decomposition products relative to the amount of carbon dioxide adsorption is the amount of decomposition products recovered relative to the amount of carbon dioxide adsorbed after one cycle of operation.
  • the decomposition product is a substance generated by decomposing the working electrode 130 and the counter electrode 140. It can be said that the smaller the amount of decomposition products relative to the amount of carbon dioxide adsorption, the more difficult it is for the working electrode 130 and counter electrode 140 of the electrochemical cell 101 to be decomposed.
  • Comparative Example 1 an electrochemical cell 101 was prepared in which PVDF was used as both the working electrode binder and the counter electrode binder. The results are shown in FIG.
  • the amount of decomposition products relative to the amount of carbon dioxide adsorption can be reduced by about 27% on average compared to Comparative Example 1. Therefore, by using PTFE as the working electrode side binder of the working electrode side electrode film 132, the working electrode 130 of the electrochemical cell 101 becomes difficult to decompose.
  • Comparative Example 1 PVDF is used for both the binder on the working electrode side and the binder on the counter electrode side, but the binding energy of the CH bond in PVDF is lower than the binding energy of the C-F bond in PTFE. . Therefore, as shown in FIG. 6, PVDF reacts with oxygen in the atmosphere, and the F element and H element contained in PVDF are desorbed as hydrogen fluoride. As a result, the working electrode side binder and the counter electrode side binder are decomposed, so that the working electrode 130 and the counter electrode 140 of the electrochemical cell 101 are easily decomposed.
  • PTFE which is the working electrode side binder
  • nanoparticles with an equivalent circle diameter of 1 ⁇ m or less.
  • the working electrode side electrode film 132 covered the entire surface of the working electrode side current collector material 131, and no exposure of the working electrode side current collector material 131 was confirmed. Further, as shown in FIG. 8, the working electrode side electrode film 132 had a uniform film structure.
  • Comparative Example 2 in the working electrode side mixing process, PTFE, which is a working electrode side binder, was dispersed and mixed as particles with an equivalent circle diameter of 5 ⁇ m. I looked into it.
  • Comparative Example 2 As shown in FIG. 9, there is a part where the working electrode side current collector 131 is exposed through the gap in the working electrode side electrode film 132, and the working electrode side electrode film 132 is exposed from the working electrode side current collector material 131. It was confirmed that the entire surface was not covered. Moreover, as shown in FIG. 10, coarse particles 300 of PTFE were present in the working electrode side electrode film 132, and the film structure was not formed homogeneously.
  • the polymer resin contained in the working electrode side binder of the working electrode side electrode film 132 is composed of carbon and halogen elements, or is composed of carbon and halogen elements. and oxygen.
  • the polymer resin contained in the working electrode side binder of the working electrode side electrode film 132 is composed of carbon and halogen elements, or is composed of carbon and halogen elements. and oxygen.
  • PTFE is used as the binder on the working electrode side.
  • the C--F bonds in PTFE are strong and resistant to oxidation. Therefore, it is possible to suppress decomposition of PTFE, which is a binder on the working electrode side, due to oxygen contained in the atmosphere.
  • an ionic liquid as an electrolyte is provided between the working electrode side electrode film 132 and the separator 150 and between the counter electrode side electrode film 142 and the separator 150.
  • the PTFE used as the working electrode side binder of this embodiment is difficult to swell due to voltage application even when an ionic liquid is provided as the electrolyte. Thereby, it is possible to suppress a decrease in durability and conductivity of the working electrode side electrode film 132.
  • the working electrode side electrode film 132 is formed after dispersing and mixing PTFE, which is the working electrode side binder, as nanoparticles with an equivalent circle diameter of 1 ⁇ m or less. .
  • PTFE which is the working electrode side binder
  • the second embodiment differs from the first embodiment in the configuration and manufacturing method of the counter electrode 140.
  • the counter electrode binder of the counter electrode film 142 contains the same polymer resin as the working electrode binder. That is, the polymer resin contained in the opposite electrode side binder is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen. That is, the counter electrode side binder contains a polymer resin that does not contain hydrogen element.
  • the polymer resin contains at least one of PTFE, FEP, PCTFE, and PFA.
  • a counter electrode mixing step is performed in which counter electrode constituent materials, which are the materials forming the counter electrode film 142, are mixed.
  • the counter electrode constituent material includes a counter electrode side active material, a counter electrode side conductive agent, and a counter electrode side binder.
  • PVFc is used as the active material on the counter electrode side
  • carbon black is used as the conductive agent on the counter electrode side
  • PTFE which is a polymer resin
  • the counter electrode constituent materials are dispersed and mixed using a homogenizer or the like, and then dissolved in a solvent to produce a mixture.
  • PTFE which is a binder on the counter electrode side, is dispersed and mixed as nanoparticles having an equivalent circle diameter of 1 ⁇ m or less.
  • NMP N-methylpyrrolidone
  • a compression step is performed to compress the mixed counter electrode constituent materials.
  • the mixed counter electrode constituent material is compressed onto the counter electrode side current collector material 141 by press molding.
  • the counter electrode film 142 is formed on the surface of the counter electrode current collector 141 . In this way, the counter electrode forming step is completed.
  • the polymer resin contained in the counter electrode binder of the counter electrode film 142 is composed of carbon and halogen elements, or is composed of carbon, halogen elements, and oxygen. It is made up of. This can prevent the opposite electrode binder from being decomposed by components contained in the atmosphere. As a result, it becomes possible to improve the electrode performance of the electrochemical cell 101.
  • PVFc is used as the counter electrode side active material among the counter electrode constituent materials. Since PVFc is flammable, high-temperature firing cannot be performed in the counter electrode forming process.
  • the counter electrode forming step of the present embodiment includes a compression step of compressing the mixed counter electrode constituent material onto the counter electrode side current collector material 141.
  • the counter electrode film 142 can be formed on the surface of the counter electrode current collector 141 without performing high-temperature firing.
  • both the working electrode binder and the counter electrode binder, or the working electrode binder alone are made of carbon and a halogen element, or are made of carbon, a halogen element, and oxygen.
  • the embodiment is not limited to this embodiment.
  • the binder on the opposite electrode side may be composed of carbon and a halogen element, or may be composed of carbon, a halogen element, and oxygen.
  • PTFE was used as the working electrode side binder or the counter electrode side binder
  • the present invention is not limited to this aspect.
  • a substance containing a polymer resin other than PTFE such as a copolymer of PTFE and PVDF, may be used as the working electrode binder or the counter electrode binder. This makes it possible to achieve both film formability and durability in the electrode films 132 and 142.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Electrochemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

An electrochemical cell according to the present invention is provided with a working electrode (130) and a counter electrode (140). The working electrode (130) adsorbs a gas to be recovered from a mixed gas, which contains the gas to be recovered, and desorbs the gas to be recovered by means of an electrochemical reaction. The counter electrode (140) exchanges electrons with the working electrode (130). An electrode film (132, 142) of at least one of the working electrode (130) and the counter electrode (140) comprises an active material, a conductive assistant and a binder. The binder contains a polymer resin. The polymer resin is configured from carbon and a halogen element, or alternatively is configured from carbon, a halogen element and oxygen.

Description

電気化学セルおよびその製造方法Electrochemical cell and its manufacturing method 関連出願の相互参照Cross-reference of related applications
　本出願は、２０２２年７月８日に出願された日本特許出願２０２２－１１０４８４号に基づくもので、ここにその記載内容を援用する。 This application is based on Japanese Patent Application No. 2022-110484 filed on July 8, 2022, and the contents thereof are incorporated herein.
　本開示は、電気化学セルおよびその製造方法に関する。 The present disclosure relates to an electrochemical cell and a method of manufacturing the same.
　特許文献１では、電気化学反応によって二酸化炭素（ＣＯ２）含有ガスから二酸化炭素を分離する二酸化炭素回収システムに用いられる電気化学セルが提案されている。特許文献１では、電気化学セルのカソードとアノードとの間に電位差を与えた状態で、カソードに二酸化炭素含有ガスを供給することで、ＣＯ２からＣＯ３ ２－が生成する電気化学反応と、ＣＯ３ ２－からＣＯ２が生成する電気化学反応が行われる。 Patent Document 1 proposes an electrochemical cell used in a carbon dioxide recovery system that separates carbon dioxide (CO 2 ) from a gas containing carbon dioxide (CO 2 ) by an electrochemical reaction. In Patent Document 1, an electrochemical reaction in which CO 3 2- is generated from CO 2 by supplying a carbon dioxide-containing gas to the cathode while applying a potential difference between the cathode and the anode of an electrochemical cell; An electrochemical reaction occurs in which CO 2 is produced from CO 3 2- .
特開平１１－３３３４０号公報Japanese Patent Application Publication No. 11-33340
　電気化学セルにおいて、カソードおよびアノードは、多孔質状の導電性部材である集電材に電極膜を結合させることにより構成されている。電極膜は、活物質および導電助剤の他にバインダを含んで構成されている。バインダは、集電材、活物質、導電助剤等の結合を補助する結合補助剤である。電気化学セルをＥＤＬＣ（電気二重層キャパシタ）や電池に用いる場合、バインダとして、溶剤に対する溶解性および化学的安定性の高いＰＶＤＦ（ポリフッ化ビニリデン）が広く採用されている。 In an electrochemical cell, a cathode and an anode are constructed by bonding an electrode film to a current collector, which is a porous conductive member. The electrode film is configured to contain a binder in addition to the active material and the conductive additive. The binder is a binding agent that assists in binding a current collector, an active material, a conductive agent, and the like. When electrochemical cells are used in EDLCs (electric double layer capacitors) and batteries, PVDF (polyvinylidene fluoride), which has high solubility in solvents and high chemical stability, is widely used as a binder.
　しかしながら、本発明者らの検討によると、電気化学セルを、大気から二酸化炭素を回収する二酸化炭素回収システムに用いる場合、大気に含まれる酸素や水分の影響によりＰＶＤＦが分解されていることが明らかになった。バインダであるＰＶＤＦが分解されると、集電材、活物質、導電助剤の間での電子の移動が確保し難くなる。また、吸着材が集電材から剥離し易くなり、電気化学セルの吸着量が経時的に低下し易くなる。その結果、電気化学セルの電極性能が低下する。 However, according to studies conducted by the present inventors, it is clear that when an electrochemical cell is used in a carbon dioxide recovery system that recovers carbon dioxide from the atmosphere, PVDF is decomposed due to the influence of oxygen and moisture contained in the atmosphere. Became. When the binder PVDF is decomposed, it becomes difficult to ensure electron transfer between the current collector, the active material, and the conductive additive. In addition, the adsorbent tends to peel off from the current collector, and the amount of adsorption in the electrochemical cell tends to decrease over time. As a result, the electrode performance of the electrochemical cell is degraded.
　本開示は、上記点に鑑みて、電極性能を向上できる電気化学セルおよびその製造方法を提供することを目的とする。 In view of the above points, the present disclosure aims to provide an electrochemical cell that can improve electrode performance and a method for manufacturing the same.
　上記目的を達成するため、本開示の一態様に係る電気化学セルは、被回収ガスを含有する混合ガスから電気化学反応によって被回収ガスの吸着と脱離を行う作用極と、
　作用極との間で電子の授受を行う対極と、を備え、
　作用極および対極の少なくとも一方を構成する電極膜は、活物質、導電助剤およびバインダを有しており、
　バインダは、高分子樹脂を含んでおり、
　高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている。 In order to achieve the above object, an electrochemical cell according to one embodiment of the present disclosure includes a working electrode that adsorbs and desorbs the recovered gas from a mixed gas containing the recovered gas through an electrochemical reaction;
A counter electrode that transfers electrons to and from the working electrode,
The electrode film constituting at least one of the working electrode and the counter electrode has an active material, a conductive aid, and a binder,
The binder contains a polymer resin,
The polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen.
　これによれば、電極膜を形成するバインダに含まれる高分子樹脂が、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されているので、混合ガスに含まれる成分によりバインダが分解されることを抑制できる。その結果、電気化学セルの電極性能を向上させることが可能となる。 According to this, since the polymer resin contained in the binder that forms the electrode film is composed of carbon and halogen elements, or is composed of carbon, halogen elements and oxygen, the components contained in the mixed gas Decomposition of the binder can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
　また、本開示の一態様に係る電気化学セルの製造方法は、被回収ガスを含有する混合ガスから電気化学反応によって被回収ガスの吸着と脱離を行う作用極と、
　作用極との間で電子の授受を行う対極と、を備え、
　作用極の電極膜を構成する作用極構成材料は、高分子樹脂を含み、
　高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている電気化学セルの製造方法において、
　作用極を形成する作用極形成工程を含み、
　作用極形成工程は、
　作用極構成材料を混合する混合工程と、
　混合工程にて混合された作用極構成材料を、高分子樹脂の熱分解温度まで加熱する加熱工程と、を含む。 In addition, a method for manufacturing an electrochemical cell according to one aspect of the present disclosure includes a working electrode that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction;
A counter electrode that transfers electrons to and from the working electrode,
The working electrode constituent material that constitutes the electrode film of the working electrode contains a polymer resin,
In a method for manufacturing an electrochemical cell in which the polymer resin is composed of carbon and halogen elements, or carbon, halogen elements and oxygen,
including a working electrode forming step of forming a working electrode,
The working electrode forming process is
a mixing step of mixing working electrode constituent materials;
The method includes a heating step of heating the working electrode constituent materials mixed in the mixing step to the thermal decomposition temperature of the polymer resin.
　これによれば、作用極構成材料に含まれる高分子樹脂を、炭素およびハロゲン元素によって構成する、あるいは炭素、ハロゲン元素および酸素によって構成するので、混合ガスに含まれる成分により高分子樹脂が分解されることを抑制できる。その結果、電気化学セルの電極性能を向上させることが可能となる。 According to this, since the polymer resin contained in the working electrode constituent material is composed of carbon and halogen elements, or carbon, halogen elements and oxygen, the polymer resin is decomposed by the components contained in the mixed gas. This can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
　また、本開示の一態様に係る電気化学セルの製造方法は、被回収ガスを含有する混合ガスから電気化学反応によって被回収ガスの吸着と脱離を行う作用極と、
　作用極との間で電子の授受を行う対極と、を備え、
　対極の電極膜を構成する対極構成材料は、高分子樹脂を含み、
　高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている電気化学セルの製造方法において、
　対極を形成する対極形成工程を含み、
　対極形成工程は、
　対極構成材料を混合する混合工程と、
　混合工程にて混合された対極構成材料を圧縮する圧縮工程と、を含む。 In addition, a method for manufacturing an electrochemical cell according to one aspect of the present disclosure includes a working electrode that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction;
A counter electrode that transfers electrons to and from the working electrode,
The counter electrode constituent material that constitutes the counter electrode film contains a polymer resin,
In a method for manufacturing an electrochemical cell in which the polymer resin is composed of carbon and halogen elements, or carbon, halogen elements and oxygen,
including a counter electrode forming step of forming a counter electrode,
The counter electrode forming process is
a mixing step of mixing counter electrode constituent materials;
The method includes a compression step of compressing the counter electrode constituent materials mixed in the mixing step.
　これによれば、対極構成材料に含まれる高分子樹脂を、炭素およびハロゲン元素によって構成する、あるいは炭素、ハロゲン元素および酸素によって構成するので、混合ガスに含まれる成分により高分子樹脂が分解されることを抑制できる。その結果、電気化学セルの電極性能を向上させることが可能となる。 According to this, since the polymer resin contained in the counter electrode constituent material is composed of carbon and halogen elements, or carbon, halogen elements and oxygen, the polymer resin is decomposed by the components contained in the mixed gas. can be suppressed. As a result, it becomes possible to improve the electrode performance of the electrochemical cell.
第１実施形態における二酸化炭素回収システムの全体構成を示す概念図である。1 is a conceptual diagram showing the overall configuration of a carbon dioxide recovery system in a first embodiment. 第１実施形態における二酸化炭素回収装置を示す説明図である。It is an explanatory view showing a carbon dioxide recovery device in a 1st embodiment. 第１実施形態における電気化学セルを示す断面図である。FIG. 1 is a cross-sectional view showing an electrochemical cell in a first embodiment. 作用極側バインダに含まれる高分子樹脂を示す図である。FIG. 3 is a diagram showing a polymer resin contained in a working electrode side binder. サイクル数と二酸化炭素吸着量に対する分解生成物量との関係を示す図である。It is a figure showing the relationship between the number of cycles and the amount of decomposition products with respect to the amount of carbon dioxide adsorption. 比較例１におけるＰＶＤＦの酸化分解を説明するための説明図である。FIG. 3 is an explanatory diagram for explaining oxidative decomposition of PVDF in Comparative Example 1. 第１実施形態における作用極側電極膜の表面を示す図である。It is a figure showing the surface of the working electrode side electrode film in a 1st embodiment. 第１実施形態における作用極側電極膜の膜構造を示す図である。FIG. 3 is a diagram showing the membrane structure of the working electrode side electrode membrane in the first embodiment. 比較例２における作用極側電極膜の表面を示す図である。3 is a diagram showing the surface of a working electrode side electrode film in Comparative Example 2. FIG. 比較例２における作用極側電極膜の膜構造を示す図である。3 is a diagram showing the membrane structure of a working electrode side electrode membrane in Comparative Example 2. FIG.
　以下に、図面を参照しながら本開示を実施するための複数の形態を説明する。各実施形態において先行する実施形態で説明した事項に対応する部分には同一の参照符号を付して重複する説明を省略する場合がある。各実施形態において構成の一部のみを説明している場合は、構成の他の部分については先行して説明した他の実施形態を適用することができる。各実施形態で具体的に組合せが可能であることを明示している部分同士の組合せばかりではなく、特に組合せに支障が生じなければ、明示してなくとも実施形態同士を部分的に組み合せることも可能である。 Hereinafter, multiple embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to those described in the preceding embodiments may be given the same reference numerals and redundant explanations may be omitted. When only part of the configuration is described in each embodiment, the other embodiments described previously can be applied to other parts of the configuration. It is not only possible to combine parts of each embodiment that specifically indicate that they can be combined, but also to partially combine parts of the embodiments even if it is not explicitly stated, as long as there is no particular problem with the combination. is also possible.
　（第１実施形態）
　本開示における第１実施形態について、図面を参照して説明する。本実施形態は、本開示における電気化学セルを、二酸化炭素を含有する混合ガスから二酸化炭素を分離して回収する二酸化炭素回収システムに適用している。したがって、本実施形態の被回収ガスは、二酸化炭素である。 (First embodiment)
A first embodiment of the present disclosure will be described with reference to the drawings. In this embodiment, the electrochemical cell according to the present disclosure is applied to a carbon dioxide recovery system that separates and recovers carbon dioxide from a mixed gas containing carbon dioxide. Therefore, the gas to be recovered in this embodiment is carbon dioxide.
　図１に示すように、本実施形態の二酸化炭素回収システム１０は、圧縮機１１、二酸化炭素回収装置１００、流路切替弁１２、二酸化炭素利用装置１３、制御装置１４が設けられている。 As shown in FIG. 1, the carbon dioxide recovery system 10 of this embodiment is provided with a compressor 11, a carbon dioxide recovery device 100, a flow path switching valve 12, a carbon dioxide utilization device 13, and a control device 14.
　圧縮機１１は、二酸化炭素含有ガスを二酸化炭素回収装置１００に圧送する。二酸化炭素含有ガスは、二酸化炭素と二酸化炭素以外のガスを含有する混合ガスであり、例えば大気を用いることができる。二酸化炭素含有ガスには、二酸化炭素以外のガスとして少なくとも酸素（Ｏ２）が含まれている。 Compressor 11 pumps carbon dioxide-containing gas to carbon dioxide recovery device 100 . The carbon dioxide-containing gas is a mixed gas containing carbon dioxide and a gas other than carbon dioxide, and for example, the atmosphere can be used. The carbon dioxide-containing gas contains at least oxygen (O 2 ) as a gas other than carbon dioxide.
　二酸化炭素回収装置１００は、二酸化炭素含有ガスから二酸化炭素を分離して回収する装置である。二酸化炭素回収装置１００は、二酸化炭素含有ガスから二酸化炭素が回収された後の二酸化炭素除去ガス、あるいは二酸化炭素含有ガスから回収した二酸化炭素を排出する。二酸化炭素回収装置１００の構成については、後で詳細に説明する。 The carbon dioxide recovery device 100 is a device that separates and recovers carbon dioxide from a carbon dioxide-containing gas. The carbon dioxide recovery device 100 discharges carbon dioxide removed gas after carbon dioxide has been recovered from the carbon dioxide-containing gas, or carbon dioxide recovered from the carbon dioxide-containing gas. The configuration of carbon dioxide recovery device 100 will be described in detail later.
　流路切替弁１２は、二酸化炭素回収装置１００の排出ガスの流路を切り替える三方弁である。流路切替弁１２は、二酸化炭素回収装置１００から二酸化炭素除去ガスが排出される場合は、排出ガスの流路を大気側に切り替え、二酸化炭素回収装置１００から二酸化炭素が排出される場合は、排出ガスの流路を二酸化炭素利用装置１３側に切り替える。 The flow path switching valve 12 is a three-way valve that switches the flow path of the exhaust gas of the carbon dioxide recovery device 100. The flow path switching valve 12 switches the flow path of the exhaust gas to the atmosphere side when carbon dioxide removal gas is discharged from the carbon dioxide recovery device 100, and switches the flow path of the exhaust gas to the atmosphere side when carbon dioxide is discharged from the carbon dioxide recovery device 100. The exhaust gas flow path is switched to the carbon dioxide utilization device 13 side.
　二酸化炭素利用装置１３は、二酸化炭素を利用する装置である。二酸化炭素利用装置１３としては、例えば二酸化炭素を貯蔵する貯蔵タンクや二酸化炭素を燃料に変換する変換装置を用いることができる。変換装置は、二酸化炭素をメタン等の炭化水素燃料に変換する装置を用いることができる。炭化水素燃料は、常温常圧で気体の燃料であってもよく、常温常圧で液体の燃料であってもよい。 The carbon dioxide utilization device 13 is a device that utilizes carbon dioxide. As the carbon dioxide utilization device 13, for example, a storage tank that stores carbon dioxide or a conversion device that converts carbon dioxide into fuel can be used. As the conversion device, a device that converts carbon dioxide into hydrocarbon fuel such as methane can be used. The hydrocarbon fuel may be a gaseous fuel at normal temperature and normal pressure, or may be a liquid fuel at normal temperature and normal pressure.
　制御装置１４は、ＣＰＵ、ＲＯＭおよびＲＡＭ等を含む周知のマイクロコンピュータとその周辺回路から構成されている。制御装置１４は、ＲＯＭ内に記憶された制御プログラムに基づいて各種演算、処理を行い、各種制御対象機器の作動を制御する。本実施形態の制御装置１４は、圧縮機１１の作動制御、二酸化炭素回収装置１００の作動制御、流路切替弁１２の流路切替制御等を行う。 The control device 14 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 14 performs various calculations and processes based on a control program stored in the ROM, and controls the operations of various devices to be controlled. The control device 14 of this embodiment performs operation control of the compressor 11, operation control of the carbon dioxide recovery device 100, flow path switching control of the flow path switching valve 12, and the like.
　図２に示すように、二酸化炭素回収装置１００は、電気化学セル１０１が設けられている。電気化学セル１０１は、作用極１３０、対極１４０およびセパレータ１５０を有している。図２に示す例では、作用極１３０、対極１４０およびセパレータ１５０をそれぞれ板状に構成している。なお、図２では、作用極１３０、対極１４０およびセパレータ１５０を、それぞれ間隔を設けて図示しているが、実際はこれらの構成要素は接するように配置されている。 As shown in FIG. 2, the carbon dioxide recovery device 100 is provided with an electrochemical cell 101. Electrochemical cell 101 has a working electrode 130, a counter electrode 140, and a separator 150. In the example shown in FIG. 2, the working electrode 130, the counter electrode 140, and the separator 150 are each formed into a plate shape. Although the working electrode 130, the counter electrode 140, and the separator 150 are shown spaced apart from each other in FIG. 2, these components are actually arranged so as to be in contact with each other.
　電気化学セル１０１は、図示しない容器内に収容されるようにしてもよい。容器には、二酸化炭素含有ガスを容器内に流入させるガス流入口と、二酸化炭素除去ガスや二酸化炭素を容器内から流出させるガス流出口を設けることができる。 The electrochemical cell 101 may be housed in a container (not shown). The container can be provided with a gas inlet that allows the carbon dioxide-containing gas to flow into the container, and a gas outlet that allows the carbon dioxide removal gas and carbon dioxide to flow out of the container.
　二酸化炭素回収装置１００は、電気化学反応によって二酸化炭素の吸着および脱離を行い、二酸化炭素含有ガスから二酸化炭素を分離して回収する。二酸化炭素回収装置１００は、作用極１３０と対極１４０に所定の電圧を印加する制御電源１２０が設けられており、作用極１３０と対極１４０の電位差を変化させることができる。作用極１３０は負極であり、対極１４０は正極である。 The carbon dioxide recovery device 100 adsorbs and desorbs carbon dioxide through an electrochemical reaction, and separates and recovers carbon dioxide from a carbon dioxide-containing gas. The carbon dioxide recovery device 100 is provided with a control power source 120 that applies a predetermined voltage to the working electrode 130 and the counter electrode 140, and can change the potential difference between the working electrode 130 and the counter electrode 140. Working electrode 130 is a negative electrode, and counter electrode 140 is a positive electrode.
　電気化学セル１０１は、作用極１３０と対極１４０の電位差を変化させることで、作用極１３０で二酸化炭素を回収する回収モードと、作用極１３０から二酸化炭素を放出する放出モードを切り替えて作動することができる。回収モードは電気化学セル１０１を充電する充電モードであり、放出モードは電気化学セル１０１を放電する放電モードである。 The electrochemical cell 101 operates by changing the potential difference between the working electrode 130 and the counter electrode 140 to switch between a recovery mode in which carbon dioxide is recovered at the working electrode 130 and a release mode in which carbon dioxide is released from the working electrode 130. Can be done. The recovery mode is a charging mode in which the electrochemical cell 101 is charged, and the discharge mode is a discharging mode in which the electrochemical cell 101 is discharged.
　回収モードでは、作用極１３０と対極１４０の間に第１電圧Ｖ１が印加され、対極１４０から作用極１３０に電子が供給される。第１電圧Ｖ１では、作用極電位＜対極電位となっている。第１電圧Ｖ１は、例えば０．５～２．０Ｖの範囲内とすることができる。 In the recovery mode, the first voltage V1 is applied between the working electrode 130 and the counter electrode 140, and electrons are supplied from the counter electrode 140 to the working electrode 130. At the first voltage V1, working electrode potential<counter electrode potential. The first voltage V1 can be within a range of 0.5 to 2.0V, for example.
　放出モードでは、作用極１３０と対極１４０の間に第１電圧Ｖ１より低い第２電圧Ｖ２が印加され、作用極１３０から対極１４０に電子が供給される。第２電圧Ｖ２は、第１電圧Ｖ１より低い電圧であればよく、作用極電位と対極電位の大小関係は限定されない。つまり、放出モードでは、作用極電位＜対極電位でもよく、作用極電位＝対極電位でもよく、作用極電位＞対極電位でもよい。 In the emission mode, a second voltage V2 lower than the first voltage V1 is applied between the working electrode 130 and the counter electrode 140, and electrons are supplied from the working electrode 130 to the counter electrode 140. The second voltage V2 only needs to be a voltage lower than the first voltage V1, and the magnitude relationship between the working electrode potential and the counter electrode potential is not limited. That is, in the release mode, the working electrode potential may be less than the counter electrode potential, the working electrode potential may be equal to the counter electrode potential, or the working electrode potential may be greater than the counter electrode potential.
　図３に示すように、電気化学セル１０１における作用極１３０は、作用極側集電材１３１及び作用極側電極膜１３２を有する。作用極側集電材１３１は、制御電源１２０に接続されるとともに、二酸化炭素含有ガスを通過させることができる多孔質状の導電性部材である。 As shown in FIG. 3, the working electrode 130 in the electrochemical cell 101 has a working electrode side current collector 131 and a working electrode side electrode film 132. The working electrode side current collector 131 is connected to the control power source 120 and is a porous conductive member through which carbon dioxide-containing gas can pass.
　作用極側集電材１３１として、例えば炭素質材料や金属材料を用いることができる。作用極側集電材１３１を構成する炭素質材料として、例えばカーボン紙、炭素布、不織炭素マット、多孔質ガス拡散層（ＧＤＬ）等を用いることができる。作用極側集電材１３１を構成する金属材料として、例えばＡｌ、Ｎｉ、ＳＵＳ等の金属をメッシュ状にした構造体を用いることができる。 As the working electrode side current collector 131, for example, a carbonaceous material or a metal material can be used. As the carbonaceous material constituting the working electrode side current collector 131, for example, carbon paper, carbon cloth, nonwoven carbon mat, porous gas diffusion layer (GDL), etc. can be used. As the metal material constituting the working electrode side current collector 131, a structure made of a metal such as Al, Ni, or SUS in a mesh shape can be used, for example.
　作用極側電極膜１３２は、二酸化炭素含有ガスから電気化学反応によって二酸化炭素の吸着と脱離を行う。作用極側電極膜１３２は、二酸化炭素吸着材、作用極側導電助剤および作用極側バインダを有する。作用極側バインダについては、後で詳細に説明する。 The working electrode side electrode film 132 adsorbs and desorbs carbon dioxide from a carbon dioxide-containing gas through an electrochemical reaction. The working electrode side electrode film 132 includes a carbon dioxide adsorbent, a working electrode side conductive agent, and a working electrode side binder. The working electrode side binder will be explained in detail later.
　二酸化炭素吸着材は、電子を受け取ることで二酸化炭素を吸着し、電子を放出することで吸着していた二酸化炭素を脱離する電気活性種（すなわち、活物質）である。二酸化炭素吸着材としては、例えば、カーボン材、金属酸化物、ポリアントラキノン等を用いることができる。 A carbon dioxide adsorbent is an electroactive species (i.e., an active material) that adsorbs carbon dioxide by receiving electrons and desorbs the adsorbed carbon dioxide by releasing electrons. As the carbon dioxide adsorbent, for example, carbon materials, metal oxides, polyanthraquinone, etc. can be used.
　作用極側導電助剤は、二酸化炭素吸着材への導電路を形成する導電物質である。作用極側導電助剤として、例えばカーボンナノチューブ、カーボンブラック、グラフェン等の炭素材料を用いることができる。 The working electrode side conductive agent is a conductive material that forms a conductive path to the carbon dioxide adsorbent. As the conductive agent on the working electrode side, carbon materials such as carbon nanotubes, carbon black, and graphene can be used, for example.
　対極１４０は、対極側集電材１４１及び対極側電極膜１４２を有する。対極側集電材１４１は、制御電源１２０に接続される導電性部材である。対極側集電材１４１は、作用極側集電材１３１と同じ材料を用いても良く、異なる材料を用いても良い。 The counter electrode 140 has a counter electrode current collector 141 and a counter electrode film 142. The counter electrode current collector 141 is a conductive member connected to the control power source 120. The counter electrode side current collector material 141 may be made of the same material as the working electrode side current collector material 131, or may be made of a different material.
　対極側電極膜１４２は、作用極側電極膜１３２との間で電子の授受を行う。対極側電極膜は、対極側活物質、対極側導電助剤および対極側バインダを有する。対極側バインダについては、後で詳細に説明する。 The counter electrode film 142 exchanges electrons with the working electrode film 132. The counter electrode film includes a counter active material, a counter conductive agent, and a counter binder. The opposite binder will be described in detail later.
　対極側活物質は、二酸化炭素吸着材との間で電子の授受を行う補助的な電気活性種である。対極側活物質は、金属の価数変化やπ電子雲への電荷出入によって電子を出し入れすることができる物質である。 The counter electrode active material is an auxiliary electroactive species that exchanges electrons with the carbon dioxide adsorbent. The counter electrode side active material is a material that can transfer electrons in and out by changing the valence of the metal and transferring charges to and from the π electron cloud.
　対極側活物質として、例えば金属イオンの価数が変化することで、電子の授受を可能とする金属錯体を用いることができる。金属錯体として、フェロセン、ニッケロセン、コバルトセン等のシクロペンタジエニル金属錯体、あるいはポルフィリン金属錯体等を挙げることができる。 As the counter electrode side active material, for example, a metal complex that enables transfer of electrons by changing the valence of metal ions can be used. Examples of the metal complex include cyclopentadienyl metal complexes such as ferrocene, nickelocene, and cobaltocene, and porphyrin metal complexes.
　本実施形態では、対極側活物質として、フェロセン骨格を持った化合物を用いる。具体的には、対極側活物質として、フェロセンが重合化したＰＶＦｃ（ポリビニルフェロセン）を用いる。 In this embodiment, a compound having a ferrocene skeleton is used as the counter electrode side active material. Specifically, PVFc (polyvinylferrocene), which is polymerized ferrocene, is used as the counter electrode side active material.
　対極側導電助剤は、対極側活物質への導電路を形成する導電物質である。対極側導電助剤は、対極側活物質と混合して用いられる。対極側導電助剤は、作用極側導電助剤と同じ材料を用いても良く、異なる材料を用いても良い。対極側導電助剤は、例えば粒子状である。 The counter electrode conductive aid is a conductive material that forms a conductive path to the counter electrode active material. The counter-electrode conductive additive is used in combination with the counter-electrode active material. The counter electrode side conductive agent may be made of the same material as the working electrode side conductive agent, or may be made of a different material. The counter electrode side conductive aid is, for example, in the form of particles.
　セパレータ１５０は、作用極側電極膜１３２と対極側電極膜１４２との間に配置される。セパレータ１５０は、作用極側電極膜１３２と対極側電極膜１４２とを分離する。すなわち、セパレータ１５０は、作用極側電極膜１３２と対極側電極膜１４２との物理的な接触を防ぐ。また、セパレータ１５０は、作用極側電極膜１３２と対極側電極膜１４２との電気的短絡を抑制する。 The separator 150 is arranged between the working electrode film 132 and the counter electrode film 142. The separator 150 separates the working electrode film 132 and the counter electrode film 142. That is, the separator 150 prevents physical contact between the working electrode film 132 and the counter electrode film 142. Moreover, the separator 150 suppresses electrical short circuit between the working electrode side electrode film 132 and the counter electrode side electrode film 142.
　セパレータ１５０として、セルロース膜やポリマー、ポリマーとセラミックの複合材料等からなるセパレータを用いることができる。セパレータ１５０として、多孔質体のセパレータを用いても良い。 As the separator 150, a separator made of a cellulose membrane, a polymer, a composite material of polymer and ceramic, etc. can be used. As the separator 150, a porous separator may be used.
　作用極側電極膜１３２とセパレータ１５０との間、および対極側電極膜１４２とセパレータ１５０との間には、イオン伝導性部材が設けられている。イオン伝導性部材は、二酸化炭素吸着材への導電を促進する。本実施形態では、イオン導電性部材として電解液が設けられている。より詳細には、電解液としてイオン液体が用いられている。イオン液体は、常温常圧下で不揮発性を有する液体の塩である。 An ion conductive member is provided between the working electrode membrane 132 and the separator 150 and between the counter electrode membrane 142 and the separator 150. The ion conductive member facilitates electrical conduction to the carbon dioxide adsorbent. In this embodiment, an electrolytic solution is provided as the ion conductive member. More specifically, an ionic liquid is used as the electrolyte. Ionic liquids are liquid salts that are nonvolatile at room temperature and pressure.
　ここで、本実施形態における作用極側バインダおよび対極側バインダについて説明する。作用極側バインダおよび対極側バインダは、接着力を有する保持材料である。 Here, the working electrode side binder and the counter electrode side binder in this embodiment will be explained. The working electrode binder and the counter electrode binder are holding materials that have adhesive strength.
　作用極側バインダは、二酸化炭素吸着材及び作用極側導電助剤を作用極側集電材１３１に保持する。具体的には、二酸化炭素吸着材、作用極側導電助剤、及び作用極側バインダの混合物が形成され、混合物が作用極側集電材１３１に接着される。二酸化炭素吸着材及び作用極側導電助剤は、作用極側バインダの内部に保持された状態となっている。 The working electrode side binder holds the carbon dioxide adsorbent and the working electrode side conductive agent on the working electrode side current collector 131. Specifically, a mixture of a carbon dioxide adsorbent, a conductive agent on the working electrode side, and a binder on the working electrode side is formed, and the mixture is adhered to the current collector 131 on the working electrode side. The carbon dioxide adsorbent and the working electrode side conductive agent are held inside the working electrode side binder.
　作用極側バインダは、高分子樹脂を含んでいる。高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている。すなわち、作用極側バインダは、水素元素（Ｈ）を含有しない高分子樹脂を含んでいる。 The working electrode side binder contains a polymer resin. The polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen. That is, the working electrode side binder contains a polymer resin that does not contain hydrogen element (H).
　図４は、本実施形態の作用極側バインダに含まれる高分子樹脂を例示している。高分子樹脂は、ＰＴＦＥ（ポリテトラフルオロエチレン）、ＦＥＰ（四フッ化エチレン・六フッ化プロピレン共重合体）、ＰＣＴＦＥ（ポリクロロトリフルオロエチレン）、ＰＦＡ（パーフルオロアルコキシアルカン）の少なくともいずれかを含んでいる。 FIG. 4 illustrates the polymer resin contained in the working electrode side binder of this embodiment. The polymer resin includes at least one of PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene/hexafluoropropylene copolymer), PCTFE (polychlorotrifluoroethylene), and PFA (perfluoroalkoxyalkane). Contains.
　対極側バインダは、対極側活物質及び対極側導電助剤を対極側集電材１４１に保持させることができ、かつ、導電性を有する材料である。対極側バインダは、作用極側バインダと同じ材料を用いても良く、異なる材料を用いても良い。本実施形態では、対極側バインダとしてＰＶＤＦを用いている。 The counter-electrode binder is a material that can hold the counter-electrode active material and the counter-electrode conductive aid on the counter-electrode current collector 141 and has electrical conductivity. The binder on the opposite electrode side may be made of the same material as the binder on the working electrode side, or may be made of a different material. In this embodiment, PVDF is used as the opposite binder.
　次に、本実施形態の電気化学セル１０１の作用極１３０を形成する作用極形成工程について説明する。 Next, a working electrode forming process for forming the working electrode 130 of the electrochemical cell 101 of this embodiment will be described.
　作用極形成工程では、まず、作用極側電極膜１３２を構成する材料である作用極構成材料を混合する作用極側混合工程を行う。作用極構成材料は、二酸化炭素吸着材、作用極側導電助剤、および作用極側バインダを含む。本実施形態では、二酸化炭素吸着剤として金属酸化物を用い、作用極側導電助剤としてカーボン材を用い、作用極側バインダとして高分子樹脂であるＰＴＦＥを用いている。 In the working electrode forming step, first, a working electrode side mixing step is performed in which working electrode constituent materials, which are the materials forming the working electrode side electrode film 132, are mixed. The working electrode constituent material includes a carbon dioxide adsorbent, a working electrode side conductive agent, and a working electrode side binder. In this embodiment, a metal oxide is used as a carbon dioxide adsorbent, a carbon material is used as a conductive agent on the working electrode side, and PTFE, which is a polymer resin, is used as a binder on the working electrode side.
　本実施形態の作用極側混合工程では、作用極構成材料を、ホモジナイザー等を用いて分散、混合させた上で溶剤（すなわち、有機溶媒）に溶解させて、混合物を生成する。このとき、作用極側バインダであるＰＴＦＥは、円相当直径１μｍ以下のナノ粒子として分散、混合される。本実施形態では、溶剤として、ＮＭＰ（Ｎ－メチルピロリドン）を用いている。 In the working electrode side mixing step of the present embodiment, the working electrode constituent materials are dispersed and mixed using a homogenizer or the like, and then dissolved in a solvent (that is, an organic solvent) to produce a mixture. At this time, PTFE, which is a binder on the working electrode side, is dispersed and mixed as nanoparticles with an equivalent circle diameter of 1 μm or less. In this embodiment, NMP (N-methylpyrrolidone) is used as the solvent.
　続いて、混合された作用極構成材料をＰＴＦＥの熱分解温度まで加熱する加熱工程を行う。本実施形態の加熱工程では、混合された作用極構成材料を作用極側集電材１３１に塗布した後、３５０℃で焼成する。これにより、作用極側集電材１３１の表面に作用極側電極膜１３２が成膜される。こうして、作用極形成工程が終了する。 Next, a heating step is performed in which the mixed working electrode constituent materials are heated to the thermal decomposition temperature of PTFE. In the heating step of this embodiment, the mixed working electrode constituent materials are applied to the working electrode side current collector material 131 and then fired at 350°C. As a result, the working electrode side electrode film 132 is formed on the surface of the working electrode side current collector material 131. In this way, the working electrode forming step is completed.
　ここで、本発明者らは、上記の作用極形成工程で得られた作用極１３０を含む電気化学セル１０１を用いた二酸化炭素の回収において、二酸化炭素吸着量に対する分解生成物量を調べた。具体的には、回収モードと放出モードとの組み合わせを１サイクルとして、各サイクルにおける二酸化炭素吸着量に対する分解生成物量を測定した。 Here, the present inventors investigated the amount of decomposition products relative to the amount of carbon dioxide adsorbed in carbon dioxide recovery using the electrochemical cell 101 including the working electrode 130 obtained in the above working electrode forming step. Specifically, the combination of the recovery mode and the release mode was defined as one cycle, and the amount of decomposition products relative to the amount of carbon dioxide adsorption in each cycle was measured.
　二酸化炭素吸着量に対する分解生成物量とは、１サイクル運転後において、吸着された二酸化炭素の量に対する回収された分解生成物の量である。分解生成物は、作用極１３０および対極１４０が分解されることにより生成された物質である。二酸化炭素吸着量に対する分解生成物量が小さい程、電気化学セル１０１の作用極１３０および対極１４０が分解され難いと言える。 The amount of decomposition products relative to the amount of carbon dioxide adsorption is the amount of decomposition products recovered relative to the amount of carbon dioxide adsorbed after one cycle of operation. The decomposition product is a substance generated by decomposing the working electrode 130 and the counter electrode 140. It can be said that the smaller the amount of decomposition products relative to the amount of carbon dioxide adsorption, the more difficult it is for the working electrode 130 and counter electrode 140 of the electrochemical cell 101 to be decomposed.
　また、比較例１として、作用極側バインダおよび対極側バインダの双方にＰＶＤＦを用いた電気化学セル１０１を用意した。その結果を図５に示す。 Furthermore, as Comparative Example 1, an electrochemical cell 101 was prepared in which PVDF was used as both the working electrode binder and the counter electrode binder. The results are shown in FIG.
　図５に示されるように、本実施形態の電気化学セル１０１を用いる場合、比較例１に対し、二酸化炭素吸着量に対する分解生成物量を平均で約２７％低減できる。したがって、作用極側電極膜１３２の作用極側バインダとしてＰＴＦＥを用いることで、電気化学セル１０１の作用極１３０が分解され難くなる。 As shown in FIG. 5, when using the electrochemical cell 101 of this embodiment, the amount of decomposition products relative to the amount of carbon dioxide adsorption can be reduced by about 27% on average compared to Comparative Example 1. Therefore, by using PTFE as the working electrode side binder of the working electrode side electrode film 132, the working electrode 130 of the electrochemical cell 101 becomes difficult to decompose.
　一方、比較例１では、作用極側バインダおよび対極側バインダの双方にＰＶＤＦを用いているが、ＰＶＤＦ中のＣ－Ｈ結合の結合エネルギは、ＰＴＦＥ中のＣ－Ｆ結合の結合エネルギよりも低い。このため、図６に示すように、ＰＶＤＦが大気中の酸素と反応し、ＰＶＤＦに含まれるＦ元素とＨ元素がフッ化水素として脱離する。これにより、作用極側バインダおよび対極側バインダが分解されるので、電気化学セル１０１の作用極１３０および対極１４０が分解され易くなる。 On the other hand, in Comparative Example 1, PVDF is used for both the binder on the working electrode side and the binder on the counter electrode side, but the binding energy of the CH bond in PVDF is lower than the binding energy of the C-F bond in PTFE. . Therefore, as shown in FIG. 6, PVDF reacts with oxygen in the atmosphere, and the F element and H element contained in PVDF are desorbed as hydrogen fluoride. As a result, the working electrode side binder and the counter electrode side binder are decomposed, so that the working electrode 130 and the counter electrode 140 of the electrochemical cell 101 are easily decomposed.
　また、本発明者らは、上記の作用極形成工程で得られた作用極側電極膜１３２について、膜表面状態および膜構造を調べた。本実施形態では、作用極側混合工程において、作用極側バインダであるＰＴＦＥを、円相当直径１μｍ以下のナノ粒子として分散、混合させている。 Further, the present inventors investigated the film surface state and film structure of the working electrode side electrode film 132 obtained in the above working electrode forming process. In this embodiment, in the working electrode side mixing step, PTFE, which is the working electrode side binder, is dispersed and mixed as nanoparticles with an equivalent circle diameter of 1 μm or less.
　本実施形態では、図７に示すように、作用極側電極膜１３２が作用極側集電材１３１の表面全体を覆っており、作用極側集電材１３１の露出は確認されなかった。また、図８に示すように、作用極側電極膜１３２は、膜構造が均質に形成されていた。 In this embodiment, as shown in FIG. 7, the working electrode side electrode film 132 covered the entire surface of the working electrode side current collector material 131, and no exposure of the working electrode side current collector material 131 was confirmed. Further, as shown in FIG. 8, the working electrode side electrode film 132 had a uniform film structure.
　これに対し、比較例２として、作用極側混合工程において、作用極側バインダであるＰＴＦＥを、円相当直径５μｍの粒子として分散、混合させた作用極側電極膜について、膜表面状態および膜構造を調べた。 On the other hand, as Comparative Example 2, in the working electrode side mixing process, PTFE, which is a working electrode side binder, was dispersed and mixed as particles with an equivalent circle diameter of 5 μm. I looked into it.
　比較例２では、図９に示すように、作用極側電極膜１３２の隙間から作用極側集電材１３１が露出している部位があり、作用極側電極膜１３２が作用極側集電材１３１の表面全体を覆えていないことが確認された。また、図１０に示すように、作用極側電極膜１３２において、ＰＴＦＥの粗大粒子３００が存在し、膜構造が均質に形成されていなかった。 In Comparative Example 2, as shown in FIG. 9, there is a part where the working electrode side current collector 131 is exposed through the gap in the working electrode side electrode film 132, and the working electrode side electrode film 132 is exposed from the working electrode side current collector material 131. It was confirmed that the entire surface was not covered. Moreover, as shown in FIG. 10, coarse particles 300 of PTFE were present in the working electrode side electrode film 132, and the film structure was not formed homogeneously.
　以上説明したように、本実施形態の電気化学セル１０１では、作用極側電極膜１３２の作用極側バインダに含まれる高分子樹脂が、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている。これにより、大気に含まれる成分により、作用極側バインダが分解されることを抑制できる。このため、作用極側集電材１３１、二酸化炭素吸着材、作用極側導電助剤の間での電子の移動を確保することができる。また、二酸化炭素吸着材が作用極側集電材１３１から剥離し難くなり、電気化学セル１０１の吸着量が経時的に低下することを抑制できる。その結果、電気化学セル１０１の電極性能を向上させることが可能となる。 As explained above, in the electrochemical cell 101 of the present embodiment, the polymer resin contained in the working electrode side binder of the working electrode side electrode film 132 is composed of carbon and halogen elements, or is composed of carbon and halogen elements. and oxygen. Thereby, it is possible to suppress decomposition of the working electrode side binder due to components contained in the atmosphere. Therefore, electron movement can be ensured between the working electrode side current collector 131, the carbon dioxide adsorbent, and the working electrode side conductive aid. Moreover, the carbon dioxide adsorbent becomes difficult to peel off from the working electrode side current collector 131, and it is possible to suppress the amount of adsorption of the electrochemical cell 101 from decreasing over time. As a result, it becomes possible to improve the electrode performance of the electrochemical cell 101.
　具体的には、本実施形態では、作用極側バインダとしてＰＴＦＥを用いている。ＰＴＦＥ中のＣ－Ｆ結合は強固であり、酸化に対しても強い。このため、大気に含まれる酸素により、作用極側バインダであるＰＴＦＥが分解されることを抑制できる。 Specifically, in this embodiment, PTFE is used as the binder on the working electrode side. The C--F bonds in PTFE are strong and resistant to oxidation. Therefore, it is possible to suppress decomposition of PTFE, which is a binder on the working electrode side, due to oxygen contained in the atmosphere.
　ところで、本実施形態の電気化学セル１０１では、作用極側電極膜１３２とセパレータ１５０との間や対極側電極膜１４２とセパレータ１５０との間に、電解液としてのイオン液体が設けられている。本発明者らの検討によると、作用極側バインダとしてＰＶＤＦを用いると、電圧が印加された際にＰＶＤＦが膨潤することが明らかになった。そして、電気化学セル１０１に電圧の印加を繰り返すことによりＰＶＤＦの膨潤収縮が繰り返され、作用極側電極膜１３２の耐久性や導電性が低下する可能性があることがわかった。 By the way, in the electrochemical cell 101 of this embodiment, an ionic liquid as an electrolyte is provided between the working electrode side electrode film 132 and the separator 150 and between the counter electrode side electrode film 142 and the separator 150. According to studies conducted by the present inventors, it has been found that when PVDF is used as a binder on the working electrode side, the PVDF swells when a voltage is applied. It has also been found that repeated application of voltage to the electrochemical cell 101 causes repeated swelling and contraction of PVDF, which may reduce the durability and conductivity of the working electrode film 132.
　これに対し、本実施形態の作用極側バインダとして用いたＰＴＦＥは、電解液としてイオン液体が設けられていた場合でも、電圧印加により膨潤し難い。これにより、作用極側電極膜１３２の耐久性や導電性が低下することを抑制できる。 On the other hand, the PTFE used as the working electrode side binder of this embodiment is difficult to swell due to voltage application even when an ionic liquid is provided as the electrolyte. Thereby, it is possible to suppress a decrease in durability and conductivity of the working electrode side electrode film 132.
　ところで、ＰＴＦＥは、溶剤に対する溶解性がほとんどないため、ＰＴＦＥを作用極側バインダとして用いると、作用極側電極膜１３２の結着性が低下する可能性が考えられる。 By the way, since PTFE has almost no solubility in solvents, if PTFE is used as the working electrode binder, there is a possibility that the binding properties of the working electrode film 132 will be reduced.
　これに対し、本実施形態の作用極形成工程では、作用極側バインダであるＰＴＦＥを、円相当直径１μｍ以下のナノ粒子として分散、混合した後、作用極側電極膜１３２を成膜している。このように、作用極側バインダの高分子樹脂の平均円相当直径を１μｍ以下とすることで、作用極側電極膜１３２の結着性を大幅に向上させることが可能となる。 In contrast, in the working electrode forming step of the present embodiment, the working electrode side electrode film 132 is formed after dispersing and mixing PTFE, which is the working electrode side binder, as nanoparticles with an equivalent circle diameter of 1 μm or less. . In this way, by setting the average equivalent circular diameter of the polymer resin of the working electrode side binder to 1 μm or less, it is possible to significantly improve the binding property of the working electrode side electrode film 132.
　（第２実施形態）
　次に、本開示における第２実施形態について説明する。本第２実施形態は、上記第１実施形態と比較して、対極１４０の構成および製造方法が異なる。 (Second embodiment)
Next, a second embodiment of the present disclosure will be described. The second embodiment differs from the first embodiment in the configuration and manufacturing method of the counter electrode 140.
　本実施形態の電気化学セル１０１では、対極側電極膜１４２の対極側バインダは、作用極側バインダと同様の高分子樹脂を含んでいる。すなわち、対極側バインダに含まれる高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている。すなわち、対極側バインダは、水素元素を含有しない高分子樹脂を含んでいる。高分子樹脂は、ＰＴＦＥ、ＦＥＰ、ＰＣＴＦＥ、ＰＦＡの少なくともいずれかを含んでいる。 In the electrochemical cell 101 of this embodiment, the counter electrode binder of the counter electrode film 142 contains the same polymer resin as the working electrode binder. That is, the polymer resin contained in the opposite electrode side binder is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen. That is, the counter electrode side binder contains a polymer resin that does not contain hydrogen element. The polymer resin contains at least one of PTFE, FEP, PCTFE, and PFA.
　次に、本実施形態の電気化学セル１０１の対極１４０を形成する対極形成工程について説明する。 Next, a counter electrode forming process for forming the counter electrode 140 of the electrochemical cell 101 of this embodiment will be described.
　対極形成工程では、まず、対極側電極膜１４２を構成する材料である対極構成材料を混合する対極側混合工程を行う。対極構成材料は、対極側活物質、対極側導電助剤、および対極側バインダを含む。本実施形態では、対極側活物質としてＰＶＦｃを用い、対極側導電助剤としてカーボンブラックを用い、対極側バインダとして高分子樹脂であるＰＴＦＥを用いている。 In the counter electrode forming step, first, a counter electrode mixing step is performed in which counter electrode constituent materials, which are the materials forming the counter electrode film 142, are mixed. The counter electrode constituent material includes a counter electrode side active material, a counter electrode side conductive agent, and a counter electrode side binder. In this embodiment, PVFc is used as the active material on the counter electrode side, carbon black is used as the conductive agent on the counter electrode side, and PTFE, which is a polymer resin, is used as the binder on the counter electrode side.
　本実施形態の対極側混合工程では、対極構成材料を、ホモジナイザー等を用いて分散、混合させた上で溶剤に溶解させて、混合物を生成する。このとき、対極極側バインダであるＰＴＦＥは、円相当直径１μｍ以下のナノ粒子として分散、混合される。本実施形態では、溶剤として、ＮＭＰ（Ｎ－メチルピロリドン）を用いている。 In the counter electrode side mixing step of this embodiment, the counter electrode constituent materials are dispersed and mixed using a homogenizer or the like, and then dissolved in a solvent to produce a mixture. At this time, PTFE, which is a binder on the counter electrode side, is dispersed and mixed as nanoparticles having an equivalent circle diameter of 1 μm or less. In this embodiment, NMP (N-methylpyrrolidone) is used as the solvent.
　続いて、混合された対極構成材料を圧縮する圧縮工程を行う。本実施形態の圧縮工程では、混合された対極構成材料を、プレス成型により対極側集電材１４１に圧着させる。これにより、対極側集電材１４１の表面に対極側電極膜１４２が成膜される。こうして、対極形成工程が終了する。 Next, a compression step is performed to compress the mixed counter electrode constituent materials. In the compression process of this embodiment, the mixed counter electrode constituent material is compressed onto the counter electrode side current collector material 141 by press molding. As a result, the counter electrode film 142 is formed on the surface of the counter electrode current collector 141 . In this way, the counter electrode forming step is completed.
　以上説明したように、本実施形態の電気化学セル１０１では、対極側電極膜１４２の対極側バインダに含まれる高分子樹脂が、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている。これにより、大気に含まれる成分により、対極側バインダが分解されることを抑制できる。その結果、電気化学セル１０１の電極性能を向上させることが可能となる。 As explained above, in the electrochemical cell 101 of the present embodiment, the polymer resin contained in the counter electrode binder of the counter electrode film 142 is composed of carbon and halogen elements, or is composed of carbon, halogen elements, and oxygen. It is made up of. This can prevent the opposite electrode binder from being decomposed by components contained in the atmosphere. As a result, it becomes possible to improve the electrode performance of the electrochemical cell 101.
　ところで、本実施形態の電気化学セル１０１では、対極構成材料のうち、対極側活物質としてＰＶＦｃを用いている。ＰＶＦｃは可燃性であるため、対極形成工程において高温焼成を行うことができない。 By the way, in the electrochemical cell 101 of this embodiment, PVFc is used as the counter electrode side active material among the counter electrode constituent materials. Since PVFc is flammable, high-temperature firing cannot be performed in the counter electrode forming process.
　これに対し、本実施形態の対極形成工程は、混合された対極構成材料を対極側集電材１４１に圧着させる圧縮工程を有している。これによれば、高温焼成を行うことなく、対極側集電材１４１の表面に対極側電極膜１４２を成膜することができる。 In contrast, the counter electrode forming step of the present embodiment includes a compression step of compressing the mixed counter electrode constituent material onto the counter electrode side current collector material 141. According to this, the counter electrode film 142 can be formed on the surface of the counter electrode current collector 141 without performing high-temperature firing.
　（他の実施形態）
　本開示は上述の実施形態に限定されることなく、本開示の趣旨を逸脱しない範囲内で、以下のように種々変形可能である。 (Other embodiments)
The present disclosure is not limited to the embodiments described above, and can be modified in various ways as described below without departing from the spirit of the present disclosure.
　（１）例えば、上述した実施形態では、作用極側バインダおよび対極側バインダの双方、または作用極側バインダ単体を、炭素およびハロゲン元素によって構成する、あるいは炭素、ハロゲン元素および酸素によって構成した例について説明したが、この態様に限定されない。例えば、対極側バインダ単体を、炭素およびハロゲン元素によって構成する、あるいは炭素、ハロゲン元素および酸素によって構成してもよい。 (1) For example, in the above-described embodiments, both the working electrode binder and the counter electrode binder, or the working electrode binder alone, are made of carbon and a halogen element, or are made of carbon, a halogen element, and oxygen. Although described, the embodiment is not limited to this embodiment. For example, the binder on the opposite electrode side may be composed of carbon and a halogen element, or may be composed of carbon, a halogen element, and oxygen.
　（２）また、上述した実施形態では、作用極側バインダまたは対極側バインダとして、ＰＴＦＥを用いた例について説明したが、この態様に限定されない。例えば、作用極側バインダまたは対極側バインダとして、ＰＴＦＥとＰＶＤＦの共重合体等、ＰＴＦＥ以外の他の高分子樹脂を含む物質を用いてもよい。これにより、電極膜１３２、１４２における成膜性と耐久性の両立を図ることができる。 (2) Furthermore, in the embodiments described above, an example was described in which PTFE was used as the working electrode side binder or the counter electrode side binder, but the present invention is not limited to this aspect. For example, a substance containing a polymer resin other than PTFE, such as a copolymer of PTFE and PVDF, may be used as the working electrode binder or the counter electrode binder. This makes it possible to achieve both film formability and durability in the electrode films 132 and 142.
　本開示は、実施例に準拠して記述されたが、本開示は当該実施例や構造に限定されるものではないと理解される。本開示は、様々な変形例や均等範囲内の変形をも包含する。加えて、様々な組み合わせや形態、さらには、それらに一要素のみ、それ以上、あるいはそれ以下、を含む他の組み合わせや形態をも、本開示の範疇や思想範囲に入るものである。 Although the present disclosure has been described based on examples, it is understood that the present disclosure is not limited to the examples or structures. The present disclosure also includes various modifications and equivalent modifications. In addition, various combinations and configurations, as well as other combinations and configurations that include only one, more, or fewer elements, are within the scope and scope of the present disclosure.

Claims (7)

  1. 　被回収ガスを含有する混合ガスから電気化学反応によって前記被回収ガスの吸着と脱離を行う作用極（１３０）と、
    　前記作用極との間で電子の授受を行う対極（１４０）と、を備え、
    　前記作用極および前記対極の少なくとも一方を構成する電極膜（１３２、１４２）は、活物質、導電助剤およびバインダを有しており、
    　前記バインダは、高分子樹脂を含んでおり、
    　前記高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている電気化学セル。     a working electrode (130) that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction;
    a counter electrode (140) that transfers electrons to and from the working electrode,
    The electrode film (132, 142) constituting at least one of the working electrode and the counter electrode includes an active material, a conductive aid, and a binder,
    The binder includes a polymer resin,
    An electrochemical cell in which the polymer resin is composed of carbon and a halogen element, or carbon, a halogen element, and oxygen.
  2. 　前記高分子樹脂の平均円相当直径は、１μｍ以下である請求項１に記載の電気化学セル。 The electrochemical cell according to claim 1, wherein the average equivalent circular diameter of the polymer resin is 1 μm or less.
  3. 　前記高分子樹脂は、ＰＴＦＥ、ＦＥＰ、ＰＣＴＦＥ、ＰＦＡの少なくともいずれかを含んでいる請求項１または２に記載の電気化学セル。 The electrochemical cell according to claim 1 or 2, wherein the polymer resin contains at least one of PTFE, FEP, PCTFE, and PFA.
  4. 　被回収ガスを含有する混合ガスから電気化学反応によって前記被回収ガスの吸着と脱離を行う作用極（１３０）と、
    　前記作用極との間で電子の授受を行う対極（１４０）と、を備え、
    　前記作用極の電極膜（１３２）を構成する作用極構成材料は、高分子樹脂を含み、
    　前記高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている電気化学セルの製造方法であって、
    　前記作用極を形成する作用極形成工程を含み、
    　前記作用極形成工程は、
    　前記作用極構成材料を混合する混合工程と、
    　前記混合工程にて混合された前記作用極構成材料を、前記高分子樹脂の熱分解温度まで加熱する加熱工程と、を含む電気化学セルの製造方法。     a working electrode (130) that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction;
    a counter electrode (140) that transfers electrons to and from the working electrode,
    The working electrode constituent material constituting the electrode film (132) of the working electrode includes a polymer resin,
    A method for producing an electrochemical cell in which the polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen,
    A working electrode forming step of forming the working electrode,
    The working electrode forming step includes:
    a mixing step of mixing the working electrode constituent materials;
    A method for manufacturing an electrochemical cell, including a heating step of heating the working electrode constituent materials mixed in the mixing step to a thermal decomposition temperature of the polymer resin.
  5. 　前記作用極構成材料は、前記被回収ガスを吸着する吸着材、作用極側導電助剤および前記高分子樹脂を含む請求項４に記載の電気化学セルの製造方法。 5. The method for manufacturing an electrochemical cell according to claim 4, wherein the working electrode constituent material includes an adsorbent that adsorbs the recovered gas, a working electrode side conductive agent, and the polymer resin.
  6. 　被回収ガスを含有する混合ガスから電気化学反応によって前記被回収ガスの吸着と脱離を行う作用極（１３０）と、
    　前記作用極との間で電子の授受を行う対極（１４０）と、を備え、
    　前記対極の電極膜（１４２）を構成する対極構成材料は、高分子樹脂を含み、
    　前記高分子樹脂は、炭素およびハロゲン元素によって構成されている、あるいは炭素、ハロゲン元素および酸素によって構成されている電気化学セルの製造方法であって、
    　前記対極を形成する対極形成工程を含み、
    　前記対極形成工程は、
    　前記対極構成材料を混合する混合工程と、
    　前記混合工程にて混合された前記対極構成材料を圧縮する圧縮工程と、を含む電気化学セルの製造方法。     a working electrode (130) that adsorbs and desorbs the gas to be recovered from a mixed gas containing the gas to be recovered through an electrochemical reaction;
    a counter electrode (140) that transfers electrons to and from the working electrode,
    The counter electrode constituent material constituting the counter electrode film (142) includes a polymer resin,
    The method for producing an electrochemical cell in which the polymer resin is composed of carbon and a halogen element, or is composed of carbon, a halogen element, and oxygen,
    including a counter electrode forming step of forming the counter electrode,
    The counter electrode forming step includes:
    a mixing step of mixing the counter electrode constituent materials;
    A method for manufacturing an electrochemical cell, comprising: a compression step of compressing the counter electrode constituent material mixed in the mixing step.
  7. 　前記対極構成材料は、前記作用極との間で電子の授受を行う対極側活物質、対極側導電助剤および前記高分子樹脂を含む請求項６に記載の電気化学セルの製造方法。 7. The method for manufacturing an electrochemical cell according to claim 6, wherein the counter electrode constituent material includes a counter electrode side active material that transfers electrons to and from the working electrode, a counter electrode side conductive agent, and the polymer resin.
PCT/JP2023/023891 2022-07-08 2023-06-28 Electrochemical cell and method for producing same WO2024009857A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022110484A JP2024008535A (en) 2022-07-08 2022-07-08 Electrochemical cell and method for manufacturing the same
JP2022-110484 2022-07-08

Publications (1)

Publication Number Publication Date
WO2024009857A1 true WO2024009857A1 (en) 2024-01-11

Family

ID=89453413

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/023891 WO2024009857A1 (en) 2022-07-08 2023-06-28 Electrochemical cell and method for producing same

Country Status (2)

Country Link
JP (1) JP2024008535A (en)
WO (1) WO2024009857A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012164912A1 (en) * 2011-05-31 2012-12-06 パナソニック株式会社 Carbon dioxide enrichment device
US20210387139A1 (en) * 2020-06-11 2021-12-16 Verdox, Inc. Electroswing adsorption cell with patterned electrodes for separation of gas components
JP2022067545A (en) * 2020-10-20 2022-05-06 株式会社デンソー Carbon dioxide recovery system
JP2022072977A (en) * 2020-10-30 2022-05-17 株式会社デンソー Carbon dioxide recovery system
JP2023044999A (en) * 2021-09-21 2023-04-03 株式会社デンソー Carbon dioxide recovery system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012164912A1 (en) * 2011-05-31 2012-12-06 パナソニック株式会社 Carbon dioxide enrichment device
US20210387139A1 (en) * 2020-06-11 2021-12-16 Verdox, Inc. Electroswing adsorption cell with patterned electrodes for separation of gas components
JP2022067545A (en) * 2020-10-20 2022-05-06 株式会社デンソー Carbon dioxide recovery system
JP2022072977A (en) * 2020-10-30 2022-05-17 株式会社デンソー Carbon dioxide recovery system
JP2023044999A (en) * 2021-09-21 2023-04-03 株式会社デンソー Carbon dioxide recovery system

Also Published As

Publication number Publication date
JP2024008535A (en) 2024-01-19

Similar Documents

Publication Publication Date Title
CA2724513C (en) Method and apparatus of forming carbon catalyst
JP7190462B2 (en) Membrane electrode assembly
JP7453651B2 (en) Electrochemical cells and carbon dioxide capture systems
US20100227255A1 (en) Cell module for fuel cell, method for forming cell module, and fuel cell
EP3988201A1 (en) Carbon dioxide recovery system and working electrode
CA2639636A1 (en) Fuel cell electrode, method for producing fuel cell electrode, membrane -electrode assembly, method for producing membrane-electrode assembly, and solid polymer fuel cell
US20240149215A1 (en) Carbon dioxide recovery system
WO2024009857A1 (en) Electrochemical cell and method for producing same
JP2018006229A (en) Polymer electrolyte and fuel battery
WO2024014483A1 (en) Electrochemical cell
WO2024009858A1 (en) Electrochemical cell
JP2004185900A (en) Electrode for fuel cell, film/catalyst layer junction, fuel cell, and manufacturing method of them
JP2023173789A (en) Carbon dioxide recovery system
JP2006059618A (en) Polymer electrolyte fuel cell
US20230381715A1 (en) Carbon dioxide recovery system
JP2009049004A (en) Method of manufacturing liquid supply type fuel cell
JP2023176216A (en) Electrochemical cell, gas recovery system equipped with electrochemical cell, and method of manufacturing electrochemical cell
JP2007103175A (en) Electrode for polymeric fuel cell and polymeric fuel cell using the same
JP2006236927A (en) Membrane electrode junction for solid polymer fuel cell
WO2024004628A1 (en) Carbon dioxide recovery system
US20220387930A1 (en) Carbon dioxide recovery system
JP2024011778A (en) electrochemical cell
JP2007299705A (en) Solid polymer fuel cell
JP2005174827A (en) Solid polymer electrolyte membrane, fuel cell using the same, and manufacturing method of them
JP2004288391A (en) Manufacturing method of membrane/electrode junction, membrane/electrode junction, and fuel cell

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23835389

Country of ref document: EP

Kind code of ref document: A1