JP5105392B2 - Electrochemical reactor tube cell and electrochemical reaction system comprising them - Google Patents

Description

  The present invention relates to an electrochemical reactor tube cell and an electrochemical reaction system such as a solid oxide fuel cell composed of the tube cell. More specifically, the present invention relates to an operation temperature lowered to 800 ° C. or lower. The present invention relates to an electrochemical reactor tube cell that can be operated in a low-temperature operating range and realizes the use of an inexpensive material and a reduction in operating cost, and an electrochemical reaction system including the same as a component. The present invention provides a new technology and a new product relating to an electrochemical reactor tube cell that is suitably used as a clean energy source and an environmental purification device.

  As a typical electrochemical reactor, there is a solid oxide fuel cell (hereinafter referred to as “SOFC”). The SOFC is a fuel cell using a solid oxide electrolyte having ionic conductivity as an electrolyte. The basic structure of the SOFC is usually composed of three layers of cathode-solid oxide electrolyte-anode, and the SOFC is usually used in a temperature range of 800 to 1000 ° C.

  When fuel gas (hydrogen, carbon monoxide, hydrocarbon, etc.) is supplied to the anode of the SOFC and air, oxygen, etc. are supplied to the cathode, there is a difference between the oxygen partial pressure on the cathode side and the oxygen partial pressure on the anode side. Therefore, a voltage according to the Nernst equation is generated between the electrodes. Oxygen becomes ions at the cathode and moves to the anode side through the solid electrolyte, and the oxygen ions reaching the anode react with the fuel gas and release electrons. Therefore, by connecting a load to the anode and the cathode, electricity can be directly taken out as a fuel cell.

  In the future, in order to put SOFC into practical use, it is essential to lower the operating temperature of SOFC. By reducing the operating temperature to 800 ° C. or lower, particularly 300 to 600 ° C., use of inexpensive materials and reduction in operating costs can be expected, and the versatility of SOFC is expected to increase as the temperature is lowered. Further, in the low temperature operating region, the SOFC characteristics are greatly dependent on the electrode structure, and for the structural control, it is also an important factor to reduce the process temperature in the SOFC manufacturing process.

  In order to lower the operating temperature of SOFC, it is inevitable to make the electrolyte thin, and so far, electrode support type cells, particularly anode support type cells, have been widely studied (Non-patent Document 1).

  However, in the conventional SOFC manufacturing process, it is necessary to sinter the anode at a high temperature of 1400 ° C. or higher, which promotes the grain growth of the anode material and is forced to have a dense structure. This is not preferable when viewed as an influence on the SOFC characteristics of the anode. Further, the anode support type cell has a problem of causing cell destruction due to an operation cycle.

  This is because nickel cermet generally used undergoes a large volume change due to a cycle of oxidation-reduction atmosphere or a change in temperature, and thus the cell is distorted and breaks down. In order to prevent this, various devices have been studied regarding the cell structure and the SOFC operation method. For example, a solid oxide fuel cell (Patent Document 1) using a porous fuel electrode tube and an air electrode tube formed in a tubular shape or a tube shape or the like was used to reduce the size of the cell, thereby increasing the thermal shock. There are also things. However, these cells also require high temperature treatment necessary for a normal SOFC manufacturing process, and do not provide a fundamental solution.

JP 2004-335277 A Nikkei Mechanical separate volume, fuel cell development forefront, Nikkei BP, June 29, 2001, p. 71-80

  In such a situation, in view of the above-mentioned conventional technology, the present inventors reduced the process temperature in the SOFC manufacturing process, thereby realized the use of inexpensive materials, reduced the operating temperature, As a result of diligent research aimed at developing new SOFC manufacturing technology and products that can reduce operating costs, the cathode is stacked on the porous structure, and the anode is impregnated on the porous structure. As a result, it has been found that the above-mentioned goal can be achieved, and further research has been made to complete the present invention.

  The present invention provides an anode tube that can be prepared even at a low temperature of 1000 ° C. or less, thereby providing an anode tube carrying an electrode material having a microstructure (particle size of 1 micron or less). In addition, it is possible to adapt materials that have been difficult to use due to high-temperature processes so far, and by suppressing the particle size growth of electrode materials by lowering the process temperature, durability against SOFC operation cycles is improved. It is an object of the present invention to provide an electrochemical reactor cell and an electrochemical reaction system that can be improved. Another object of the present invention is to provide a cell stack manufacturing technique that can easily change the anode support material and its product in accordance with various fuel gases and use conditions without changing the process itself. .

The present invention for solving the above-described problems comprises the following technical means.
(1) A cathode (air electrode) is laminated on a structure having an electrolyte layer (ion conduction phase) outside a porous structure having a porous tube structure of 2 mm even if the outer diameter of the tube is large , the anode in the porous structure portion (fuel electrode) material is a impregnated supported have that electric reactor cell,
The thickness of the electrolyte layer is 1 to 100 microns, the particles of the anode material are uniformly arranged in submicrons with a particle diameter of 0.01 to 1 micron, and the anode material is three-dimensionally bonded. An electrochemical reactor cell characterized by that.
( 2 ) The material of the porous structure and / or electrolyte is selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W. an oxide compound containing two or more elements, the (1) Symbol placement of electrochemical reactor cell.
( 3 ) An element selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti and / or these elements 1 as the anode (fuel electrode) material supported on the porous structure portion composed of an oxide compound containing more than, the (1) Symbol placement of electrochemical reactor cell.
( 4 ) The cathode (air electrode) material is composed of an element selected from Ag, La, Sr, Mn, Co, Fe, Sm, and / or an oxide compound containing one or more of these elements. wherein (1) Symbol placement of electrochemical reactor cell.
( 5 ) The electrochemical reactor cell according to ( 4 ), wherein the cathode material is a transition metal perovskite oxide or a composite of a transition metal perovskite oxide and a solid electrolyte material.
( 6 ) An electrochemical reaction system for extracting an electric current by an electrochemical reaction, comprising the electrochemical reactor cell according to any one of (1) to ( 5 ) as a reactor. .
( 7 ) The electrochemical reaction system according to ( 7 ), wherein the electrochemical reaction system is a solid oxide fuel cell that can be used in a low temperature operating range of 300 to 800 ° C. with a reduced operating temperature.
( 8 ) The electrochemical reaction system according to ( 7 ) above, wherein units in which a plurality of electrochemical reactor cells are combined are stacked.

Next, the present invention will be described in more detail.
In the present invention, in particular, a cathode (air electrode) is laminated on a structure having an electrolyte layer (ion conductive phase) outside the porous structure, and an anode (fuel electrode) material is formed on the porous structure portion. The cathode tube (air electrode) is laminated on a structure having a dense electrolyte layer (ion conducting phase) outside the porous tube structure and the porous tube structure part. Is characterized in that the anode (fuel electrode) material is impregnated and supported, and the anode material is three-dimensionally bonded.

  Conventionally, when producing a tube-type electrochemical cell, an anode material is produced as a tube (usually including sintering at 1400 ° C. or higher), an electrolyte is laminated, and sintered (usually at 1400 ° C. or higher), followed by a cathode There are a plurality of process steps of attaching and sintering (usually 1000 ° C. or higher), which is complicated. However, according to the structure of the electrochemical reactor tube cell of the present invention, first, since the electrolyte and the electrode porous portion are produced at the same time, a plurality of electrodes can be attached and attached at the same time, and high-temperature sintering is unnecessary. Thus, the manufacturing process of the electrochemical reactor tube cell can be simplified, thereby reducing the cost. The anode material is impregnated into the porous tube on a solution basis, but these solutions can be supported at a sintering temperature of 1000 ° C. or lower, so the temperature can be lowered including simultaneous sintering of the anode and the cathode. The process becomes possible.

  According to the above configuration, since the electrode material is supported at a low temperature, the diameter of the anode material particles is uniformly arranged at a submicron, so that thermal expansion and contraction are minimized with respect to changes in the operation cycle. Therefore, it is possible to construct a high-performance electrochemical reactor that can be operated efficiently over a long period of time. In the present invention, it is important that the supported anode material is three-dimensionally bonded. This is necessary and important to minimize the electrical resistance of the anode.

  Examples of the electrochemical reaction system targeted by the present invention include a solid oxide fuel cell (SOFC), an exhaust gas purification reactor, a hydrogen production reactor, and the like. In the electrochemical reactor tube cell of the present invention, an anode, an electrolyte By selecting an appropriate cathode material, a highly efficient SOFC can be constructed.

  Further, in the present invention, by making the material of the porous tube the same as the electrolyte, it becomes possible to produce a tube having a seamless dense electrolyte portion and a porous portion, thereby improving the efficiency from the anode to the electrolyte. Good ion conduction is realized.

  In the present invention, the porous tube and the electrolyte material are required to be materials having high ionic conductivity, so that Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr are used. , Ga, Bi, Nb, and W are preferably oxide compounds containing two or more elements selected from W, W, Nb, and W.

  In the present invention, the anode (fuel electrode) material supported on the porous tube is preferably a material having high activity with respect to the fuel gas. Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr In order to realize a highly efficient electrochemical reactor, it is necessary to have a structure containing one or more elements of Ti and Ti and / or oxide compounds.

  Furthermore, in the present invention, the cathode (air electrode) material is preferably a material having high activity for ionization of oxygen, and in particular, an element of Ag, La, Sr, Mn, Co, Fe, Sm, Ca and / or an oxide compound is used. A material composed of one or more types is preferred. Hereinafter, an electrochemical reactor tube cell according to an embodiment of the present invention and an electrochemical reaction system including the same will be described in detail.

  First, the structure of the electrochemical reactor tube cell according to the present invention will be described. FIG. 1 is a schematic view of an electrochemical reactor tube cell according to the present invention. As shown in FIG. 1, a porous tube 5 having a porous structure is disposed inside a dense electrolyte layer 1. The cathode 4 is disposed outside the electrolyte layer. An anode material is impregnated in the porous structure of the porous tube and sintered at a low temperature to constitute an electrochemical reactor tube cell.

  Next, the electrolyte layer 1 will be described. FIG. 2 shows a cross section of an electrochemical reactor tube cell. The thickness of the electrolyte layer 1 is determined in consideration of the tube diameter of the porous tube, the specific resistance of the electrolyte layer 1 itself, and the like. The electrolyte layer 1 is dense and preferably has a thickness in the range of 1 to 100 microns, and preferably 50 microns or less in order to suppress the electric resistance of the electrolyte.

Since this electrolyte has a porous structure laminated on the surface, the thickness can be easily reduced. This porous structure develops and uses a function as an electrode by supporting an anode material, and also has a function as a support tube. Normally, under the conditions of use as a fuel cell, a fuel gas such as hydrogen, carbon monoxide, methane or the like is supplied into the tube of the porous structure, and an oxidant gas such as air or oxygen is outside the tube. Supplied.

  Here, in the electrochemical reactor tube cell according to the present invention, the tube diameter, tube length, and tube thickness of the porous structure are not particularly limited, and the entire size of the required electrochemical reactor tube cell is not limited. In consideration of the above, it can be arbitrarily determined so as to obtain necessary characteristics as an anode or a cathode. Also, the porosity of the porous structure can be variously controlled so that the three-phase interface (reaction field) is maintained and the tube strength does not decrease.

  By making the material of the porous tube the same material as the electrolyte, it becomes possible to produce a tube having a seamless dense electrolyte portion and a porous portion, and efficient ion conduction from the electrode to the electrolyte is realized. As materials used for these, two or more elements selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W are used. It is desirable that the oxide compound contains.

Among them, stabilizers such as yttria (Y ₂ O ₃ ), calcia (CaO), scandia (Sc ₂ O ₃ ), magnesia (MgO), ytterbia (Yb ₂ O ₃ ), erbia (Er ₂ O ₃ ), etc. Suitable examples include stabilized zirconia and yttria (Y ₂ O ₃ ), ceria (CeO ₂ ) doped with gadolinia (Gd ₂ O ₃ ), samaria (Sm ₂ O ₃ ), and the like. Stabilized zirconia can be stabilized by one or more stabilizers, and can also be a composite with alumina (Al ₂ O ₃ ).

  Specifically, yttria-stabilized zirconia (YSZ) added with 5 to 10 mol% yttria as a stabilizer, gadolinia doped ceria (GDC) added with 5 to 10 mol% gadolinia as a dopant, and the like are preferable examples. Can be mentioned.

For example, in the case of YSZ, it is not preferable that the yttria content is less than 5 mol% because the oxygen ion conductivity of the anode is lowered. On the other hand, if the yttria content exceeds 10 mol%, the oxygen ion conductivity of the anode similarly decreases, which is not preferable. The same applies to GDC.

  The anode material supported by the porous structure is a metal selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, and / or an oxide composed of one or more of these elements. In addition, it functions as a catalyst. Specifically, for example, nickel (Ni), cobalt (Co), ruthenium (Ru), and the like are preferable examples. Among these, nickel (Ni) can be suitably used because it is cheaper than other metals and has a sufficiently high reactivity with fuel gas such as hydrogen. Moreover, the composite which mixed these elements and oxides can also be used. The particle size of the anode material particles is 1 micron or less, preferably 0.1 micron or less. Thereby, high activity is obtained by reaction with fuel gas.

  On the other hand, as the material of the cathode, a material having high activity for ionization of oxygen is preferable. In particular, elements of Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ni, Mg and / or oxide compounds thereof are used. A material composed of one or more of the above is preferable. Among them, for example, transition metal perovskite oxides, and composites of transition metal perovskite oxides and solid electrolyte materials can be preferably used. In the case of using a composite, oxygen ion conductivity is improved among the electron conductivity and oxygen ion conductivity, which are necessary characteristics of the cathode, so that oxygen ions generated at the cathode easily migrate to the solid electrolyte layer. Thus, there is an advantage that the electrode activity of the cathode is improved.

  Here, when the composite of the transition metal perovskite oxide and the second solid electrolyte is used, the mixing ratio of the former and the latter is preferably in the range of 90:10 wt% to 70:30 wt%. It is because it is excellent in balance, such as activity and the consistency of a thermal expansion coefficient, More preferably, it is 90:10 weight%-80:20 weight%.

Specific examples of the transition metal perovskite oxide include LaSrMnO ₃ , LaCaMnO ₃ , LaMgMnO ₃ , LaSrCoO ₃ , LaCaCoO ₃ , LaSrFeO ₃ , LaSrCoFeO ₃ , LaSrNiO ₃ Co, and SmS ₃ Can be mentioned.

  However, as shown in FIG. 1, anode exposed portions are formed at both ends of the porous tube by exposing a part of the porous tube without laminating the solid electrolyte layer. This exposed portion functions as an external lead electrode of the anode. The exposure amount of the exposed portion is not particularly limited, and can be appropriately adjusted in consideration of the gas seal member, the electrode current collecting method, the gas outlet flow path, and the like.

  Next, an example of an operation method for operating the electrochemical reactor tube cell according to the present invention as a single SOFC will be described. As shown in FIG. 3, the exposed portions of the tubes are arranged in the fuel introduction pipes 8 a and 8 b, and the exposed portions are sealed in the fuel introduction pipe by the sealing material 9. Specific examples of the main material constituting the fuel gas introduction means include heat-resistant stainless steel, ceramics and the like, depending on the operating conditions of the SOFC.

That is, an electrochemical reactor tube cell is mounted inside the fuel introduction pipe, and each electrode connection portion is sealed with a sealing material. The material of the sealing material is not particularly limited as long as it does not transmit gas. However, it is necessary to match the thermal expansion coefficient of the anode portion. Specifically, for example, ceramics such as mica glass and spinel (MgAl ₂ O ₄ ) are preferable examples.

A current collector 11 is attached to the electrode surface (the anode exposed portion and the cathode). Specific examples of the main material constituting the current collector 11 include conductive ceramics such as lanthanum chromite (LaCrO ₃ ), noble metal meshes such as gold, silver and platinum, stainless steel, nickel mesh, nickel felt, and the like. Is a suitable example.

  Also, using another oxidant gas or fuel gas introduction means (not shown) (for example, an external manifold), the fuel gas is introduced into the anode part and the oxidant gas is introduced from the exposed surface of the cathode part, and is collected from the pipe connection part. By connecting the load 12 to the electric body 11 via the current collecting wires 10a and 10b, power generation is possible.

  In the above description, an example of an operation method for operating the electrochemical reactor tube cell according to the present invention as a single unit as SOFC has been described. However, the operation method is not particularly limited. Further, a unit in which electrochemical reactor tube cells according to the present invention are assembled in parallel can be used as a unit, and a plurality of these units can be stacked to constitute a power generation device.

  Next, the operation of the electrochemical reactor tube cell according to the present invention will be described. The electrochemical reactor tube cell according to the present invention has a dense electrolyte layer in a porous structure formed in a tubular shape, an anode material is supported on the porous structure, and the cathode is a porous structure. It is formed on the outside.

  Compared to the conventional anode process temperature, which is usually 1400 ° C. or higher to achieve mechanical strength, this method requires sufficient high temperature sintering because the porous structure has sufficient mechanical strength. Therefore, the anode can be prepared in a temperature range of 1000 ° C. or lower. This allows the anode material to be present in the porous structure with a low particle size of 1 micron or less, thus realizing high catalytic activity of the anode.

  In the present invention, the integrated structure can be simplified as compared with the conventional integrated structure, so that the cell manufacturing process can be simplified, thereby reducing the cost. In the cell manufacturing process of the present invention, the low temperature region sintering can minimize problems such as the thermal expansion coefficient of materials such as conventional materials and the chemical reaction between the electrolyte and electrode material due to co-sintering. It is possible to combine various materials.

  Next, the suitable manufacturing method of the electrochemical reactor tube cell based on this invention is demonstrated. The method for producing an electrochemical reactor tube cell according to the present invention basically includes the following steps.

  That is, a step of producing a porous tube, a step of bonding a solid electrolyte layer to the outer surface of the porous tube, a step of impregnating the anode material with the porous tube, and applying a cathode to the outside of the solid electrolyte layer, And a step of sintering. Details will be described below.

  First, a porous tube is produced using an electrolyte material. Specifically, an oxide containing two or more elements selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W A pore-forming agent such as a cellulose-based binder and carbon powder is added to the compound powder, and the mixture is kneaded with water. The resulting plastic mixture is extruded into a predetermined tube diameter, tube length, and tube. Molded into a thick tubular shaped body.

  Next, after drying the obtained tube molded body, a slurry containing the same electrolyte material powder is adhered, and then dried. Thereby, it becomes a tube which the electrolyte layer forming layer used as a solid electrolyte layer by the subsequent baking adhered to the surface of the tube.

  Examples of the method for attaching the slurry include a method in which openings on both ends of a porous tube are sealed with a resin adhesive, and then the tube is immersed in a slurry containing a solid electrolyte and dip coated. A suitable example is given. In addition to the dipping method, various adhesion methods such as a brush coating method and a spray method can be used.

  At this time, it is necessary to form an exposed portion in which the porous portion is exposed without attaching the slurry containing the solid electrolyte to one end of the outer surface of the obtained porous tube with the electrolyte layer. .

  This is fired at a predetermined temperature to obtain a porous tube with an electrolyte layer. The firing temperature of the tube is preferably fired at a temperature of about 1200 to 1600 ° C., but is not particularly limited, and the temperature at which the electrolyte layer becomes dense considering the tube material, porosity, etc. Adopted. The obtained porous tube can be further machined so as to have a predetermined tube diameter, tube length, and tube thickness.

  Next, the process of impregnating the anode material into the porous tube with electrolyte will be described. The anode material can be supported using a polymer solution or a plating solution containing the above metal ions prepared by a complex polymerization method or the like, but is not limited thereto, and is not limited to a gas phase method. Etc. can also be used. Here, an example using a complex polymerization method will be described. A solution prepared by mixing a metal salt containing one or more anode materials with water, alcohol, ethylene glycol, or the like is prepared. As the material, metal salts containing metal elements selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, and Ti, for example, nitrates, acetates, chlorides, and the like are particularly suitable. A solution in which a necessary amount of these is mixed is stirred on a hot plate at 80 to 250 ° C., and the viscosity of the solution is appropriately adjusted.

  As shown in FIG. 4, the porous tube with an electrolyte is immersed in this solution, dried, and then impregnated and dried. The required amount can be carried by repeating this cycle. The number of repetitions varies depending on the concentration of the anode material in the solution and the required loading amount, and is appropriately set according to the necessity. The drying temperature can be appropriately adopted as long as it is a temperature at which the organic compound in the solution is burned, but for example, 200 to 400 ° C is preferable.

  A cathode material is then applied to the electrolyte layer. As the cathode material, in particular, a material composed of one or more selected from Ag, La, Sr, Mn, Co, Fe, Sm, and / or an oxide compound thereof is suitable. A slurry can be prepared from this powder, and the cathode can be formed on the electrolyte layer using the same method as that for the preparation of the solid electrolyte.

  Next, the obtained tube is fired at a predetermined temperature to produce an electrochemical reactor tube cell. The firing temperature is preferably, for example, about 800 to 1200 ° C., but is not particularly limited, and can be variously adjusted in consideration of the type of the cathode material and the like.

  As described above, the electrochemical reactor tube in which the anode material is impregnated in the porous tube portion in the porous tube with the electrolyte in which the solid electrolyte layer is bonded to the outer surface of the porous tube, and the cathode is laminated outside the electrolyte layer. A cell can be obtained.

  If necessary, the cathode or anode portion of the obtained electrochemical reactor tube cell can be machined to adjust the surface and adjust the dimensions. Moreover, in the above production method, the porous tube with electrolyte was prepared in advance by firing the tube coated with the electrolyte slurry, and the cathode was laminated after impregnating the anode. It is also possible to appropriately impregnate the anode material after sealing the cathode surface with a resin adhesive after laminating the cathode.

  When laminating these electrochemical reactor tube cells as a stack, it is possible to arrange and fix a plurality of porous tubes with electrolytes in parallel while being spaced apart from each other, and simultaneously impregnate the anode material as appropriate It is. Furthermore, it is possible to appropriately attach a slurry containing the cathode material to the electrolyte surface of the tubular molded body before impregnating the anode material and seal the surface with a resin adhesive or the like. Thereafter, the plurality of tubes can be arranged and fixed in parallel in a state of being separated from each other, and the anode material can be impregnated. In such a case, since the number of firings can be reduced, further cost reduction can be achieved.

  In addition, when a stack is formed in an electrochemical reactor tube cell, it is possible to integrally connect tubes having an electrolyte layer bonded to the outer surface of a porous tube with a cathode material, which is conventionally difficult to connect. Even when the outside of the tube is in an oxidizing atmosphere, the tubes can be easily electrically connected without using an expensive precious metal wire or the like.

  The electrochemical reactor cell made according to the present invention has the following characteristics. That is, the electrolyte thickness is 1 to 100 microns, the anode material is submicron with a particle diameter of 0.01 to 1 micron, the operating temperature range is 300 to 800 ° C., and the anode has a porous structure. The body part is impregnated and supported, the anode material is three-dimensionally bonded, the cathode is laminated on the surface of the electrolyte layer outside the porous structure, and the thickness is 10 to 50 microns. .

The following effects are exhibited by the present invention.
(1) An electrochemical reactor having an operating temperature reduced to 800 ° C. or lower, particularly 300 to 600 ° C. can be provided.
(2) The process temperature in the manufacturing process of the electrochemical reactor can be lowered, thereby realizing the use of an inexpensive material and a significant reduction in the manufacturing cost.
(3) The anode particle size can be suppressed to submicron or less by reducing the process temperature (reducing the process temperature makes it possible to combine difficult materials in the past).
(4) Since the anode particle size is suppressed to a submicron level, it is possible to manufacture and provide a high-performance electrochemical reactor cell with significantly improved anode characteristics.
(5) A solid oxide fuel cell using the electrochemical reactor cell can be provided.
(6) By constructing a stack including the electrochemical reactor cell, it is possible to easily construct a laminated structure in which the porous structures are laminated without using expensive noble metal wires or the like.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

In this example, an electrochemical reactor tube cell was produced according to the following procedure. First, nitrocellulose as a binder and carbon powder as a pore-forming agent are added to a powder having a ZrO ₂ -10 mol% Y ₂ O ₃ composition (made by Tosoh Corporation), kneaded with water to form a clay, and then extruded. A tubular molded body was molded by a molding method. The obtained tube-shaped molded body had a tube diameter, a tube thickness, and a tube length of 2 mm, 0.5 mm, and 40 mm, respectively (tube outer diameter 2 mm, tube inner diameter 1 mm).

Next, after opening the opening at one end of the obtained tubular molded body with vinyl acetate, the tube is immersed in a slurry containing a solid electrolyte having a composition of ZrO ₂ -10 mol% Y ₂ O ₃ to form an electrolyte layer. The layer was dip-coated to obtain a tubular molded body with an electrolyte. At this time, the other end of the porous anode tube was exposed by 5 mm to form an exposed portion. Next, this tubular molded body was dried and then fired at 1450 ° C. for 2 hours to obtain a porous tube with an electrolyte.

  Next, a porous tube with an electrolyte in which the electrolyte portion was sealed with vinyl acetate was immersed in a solution containing nickel nitrate and ethylene glycol, so that the porous portion was impregnated with nickel. After drying at 350 ° C., nickel was impregnated again and this cycle was repeated 10 times. FIG. 5 shows a SEM cross-sectional photograph of the porous tube impregnated with the anode material thus produced. In the enlarged view of the porous tube, it can be seen that nickel particles are supported with a particle size of about 100 nm and the particles are three-dimensionally bonded. FIG. 6 shows changes in the total particle surface area due to the decrease in particle diameter. As can be seen from the figure, the surface area dramatically increases when the particle diameter is 1 micron or less. This shows that high electrode activity can be expected in the anode tube of the present invention.

Next, a paste containing LaSrCoFeO ₃ (manufactured by Nippon Ceramics Co., Ltd.) as a cathode material is applied to the electrolyte layer surface, dried at 100 ° C., and then fired at 1000 ° C. for 1 hour to integrally sinter the electrolyte layer and the cathode material. I let you. Thereby, an electrochemical reactor tube cell was obtained.

  FIG. 7 shows the electric conductivity of the obtained anode tube (containing nickel oxide 35 wt%). It can be seen that, despite the low nickel content, these values are sufficient for electrodes. Also, these conductivities can be easily controlled by further supporting the anode material.

  The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above embodiment, the cathode is laminated after supporting the anode material. In this case, the anode is sintered at 1000 ° C. However, it is possible to lower the sintering temperature of the anode to 1000 ° C. or lower by supporting nickel after sintering the cathode first.

  As described above in detail, the present invention relates to an electrochemical reactor tube cell and an electrochemical reaction system. According to the electrochemical reactor tube cell according to the present invention, first, an electrolyte and a porous structure are simultaneously formed. Since the electrode is supported by a solution after that, a plurality of tubes can be prepared simultaneously, and the manufacturing process of the electrochemical reactor tube cell can be simplified by eliminating the need for high-temperature sintering. Cost can be reduced.

  Further, according to the above configuration, since the anode material is supported at a low temperature of 1000 ° C. or lower, the diameter of the anode material particles is uniformly arranged at a submicron. In addition, it is possible to provide an electrochemical reactor capable of minimizing shrinkage and capable of operating efficiently over a long period of time. In addition, since the particle size of the anode material is kept low, the anode characteristics can be effectively enhanced.

  In addition, materials that have been difficult to use due to high-temperature processes can be applied, and the anode material can be easily changed without changing the process itself according to various fuel gases and usage conditions. An electrochemical reactor cell can be manufactured.

1 is a schematic view of an electrochemical reactor tube cell according to the present invention. FIG. It is sectional drawing of an electrochemical reactor tube cell. It is a block diagram in the case of using the electrochemical reactor tube cell which concerns on this invention as SOFC single-piece | unit. It is the figure which showed the process in which an anode material is impregnated in the porous tube with electrolyte, and the cathode material is applied and sintered. It is a SEM cross-sectional photograph of the porous tube which impregnated the anode material. The change of the particle | grain total surface area by the reduction | decrease of a particle diameter is shown. The electric conductivity of the anode tube prepared at low temperature at 800 ° C. is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte layer 2 Anode 3 Tube hole 4 Cathode 5 Porous tube 6 Anode exposed part 7 Fuel gas 8a, 8b Fuel introduction pipe 9 Sealing material 10a, 10b Current collector wire 11 Current collector 12 Load

Claims (8)

Even if the outer diameter of the tube is large , a cathode (air electrode) is laminated on a structure having an electrolyte layer (ion conducting phase) outside a porous structure having a porous tube structure of 2 mm, and has a porous structure. the body part is an anode (fuel electrode) material a that electrical reactor cell is impregnation,
The thickness of the electrolyte layer is 1 to 100 microns, the particles of the anode material are uniformly arranged in submicrons with a particle diameter of 0.01 to 1 micron, and the anode material is three-dimensionally bonded. An electrochemical reactor cell characterized by that. The porous structure and / or electrolyte material is selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W 2 an oxide compound containing more than one element, according to claim 1 Symbol placement of electrochemical reactor cell. The anode (fuel electrode) material to be supported on the porous structure portion is an element selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti and / or one or more of these elements. composed of an oxide compound containing, claim 1 Symbol placement of electrochemical reactor cell. Cathode (air electrode) material is comprised Ag, La, Sr, Mn, Co, Fe, Sm, from the elements and / or is selected from Ca oxide compounds containing one or more of these elements, according to claim 1 serial mounting of the electrochemical reactor cell. The electrochemical reactor cell according to claim 4 , wherein the cathode material is a transition metal perovskite oxide or a composite of a transition metal perovskite oxide and a solid electrolyte material. An electrochemical reaction system for taking out an electric current by an electrochemical reaction, comprising the electrochemical reactor cell according to any one of claims 1 to 5 as a reactor. The electrochemical reaction system according to claim 7 , which is a solid oxide fuel cell that can be used in a low-temperature operating range of 300 to 800 ° C. with a reduced operating temperature. The electrochemical reaction system according to claim 7 , wherein units combining a plurality of electrochemical reactor cells are stacked.