Oxide ion conductive solid electrolyte

Abstract

An oxide ion–conducting solid electrolyte comprising: a mayenite compound having a typical composition represented by Ca12Al14O33; and a crystal phase of cerium oxide (CeO2).

Description

[Technical Field]

[0001] This invention relates to an oxide ion conductive solid electrolyte. [Background technology]

[0002] Solid electrolytes with oxide ion conductivity can be used in various electrical devices, such as solid oxide fuel cells (SOFCs), solid oxide electrolytic cells (SOECs), oxygen sensors, and oxygen pumps.

[0003] In recent years, highly efficient energy systems combining SOFCs and SOECs have attracted attention as one way to realize the Power to Gas / Chemical technology concept, which has been gaining attention for the widespread adoption of renewable energy.

[0004] Both SOFCs and SOECs are electrochemical cells that operate at high temperatures. The former can handle various fuels such as hydrogen, carbon monoxide, and methane, while the latter can electrolyze the water and carbon dioxide produced by the operation of SOFCs and convert them back into hydrogen and carbon monoxide.

[0005] SOFCs and SOECs have a solid electrolyte placed between two electrodes, and they operate through the conduction of oxide ions within this solid electrolyte. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2019 / 189701 [Non-patent literature]

[0007] [Non-Patent Document 1] M. Lacerda et al., “High Oxide ion conductivity in Ca12Al14O33” Nature, vol. 332, P525, 7, April (1988) [Non-Patent Document 2] FMLea, CHDesch, The Chemistry of Cement and Concrete, 2nd ed., p.52, Edward Arnold&Co., London, 1956 [Non-Patent Document 3] A.Pedone et al.J.Phys.Chem.B 110, 11780-11795(2006) [Non-Patent Document 4] LBSkinner et al.Phys.Rev.Lett. 112, 157801(2014) [Overview of the project] [Problems that the invention aims to solve]

[0008] To date, materials such as yttria-stabilized zirconia (YSZ) and scandia-stabilized zirconia (ScSZ) have been proposed as solid electrolytes for SOFCs and SOECs.

[0009] Furthermore, it has recently been reported that meienite-type compounds exhibit oxide ion conductivity (Non-Patent Literature 1). Meienite-type compounds have a crystalline structure that contains free oxide ions within the cage. Therefore, these free oxide ions may contribute to ionic conduction.

[0010] However, according to the inventors of the present invention, the ionic conductivity of conventional meienite-type compounds is not very high (for example, about 1 / 10th that of YSZ).

[0011] Therefore, further measures are needed to apply meienite-type compounds to oxide ion-conducting solid electrolytes.

[0012] This invention has been made in view of the above background, and aims to provide a solid electrolyte containing a myenite-type compound and having significantly high oxide ion conductivity.

Means for Solving the Problem

[0013] In the present invention, an oxide ion conductive solid electrolyte is provided, which comprises Ca 12 Al 14 O 33 a melilite-type compound having a representative composition represented by and a crystal phase of cerium oxide (CeO2), and an oxide ion conductive solid electrolyte is provided.

Advantages of the Invention

[0014] In the present invention, a solid electrolyte having a melilite-type compound and significantly high oxide ion conductivity can be provided.

Brief Description of the Drawings

[0015] [Figure 1] FIG. schematically shows an example of the configuration of a SOFC having an oxide ion conductive solid electrolyte according to an embodiment of the present invention. [Figure 2] FIG. schematically shows an example of the configuration of a SOEC having an oxide ion conductive solid electrolyte according to an embodiment of the present invention. [Figure 3] FIG. schematically shows an example of the flow of a method for manufacturing an oxide ion conductive solid electrolyte according to an embodiment of the present invention. [Figure 4] FIG. schematically shows an example of the flow of another method for manufacturing an oxide ion conductive solid electrolyte according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the present invention will be described.

[0017] (Oxide Ion Conductive Solid Electrolyte According to an Embodiment of the Present Invention) In one embodiment of the present invention, an oxide ion conductive solid electrolyte is provided, which comprises Ca 12 Al14 O 33 A melilite-type compound having a representative composition represented by, a crystal phase of cerium oxide (CeO2), and an oxide ion-conductive solid electrolyte is provided.

[0018] The oxide ion-conductive solid electrolyte according to one embodiment of the present invention (hereinafter referred to as "the first solid electrolyte") contains a melilite-type compound having a C12A7 structure.

[0019] The melilite-type compound has a representative composition represented by 12CaO·7Al2O3 and has a characteristic crystal structure having three-dimensionally connected voids (cages) with a diameter of about 0.4 nm.

[0020] The framework constituting this cage is positively charged and forms 12 cages per unit cell. 1 / 6 of this cage is occupied by oxide ions inside in order to satisfy the electrical neutral condition of the crystal. However, the oxide ions in this cage have characteristics chemically different from those of other oxygen ions constituting the framework. Therefore, the oxide ions in the cage are particularly called free oxide ions.

[0021] The melilite-type compound has a composition formula [Ca 24 Al 28 O 64 4+ (O 2- )2 (Non-Patent Document 2).

[0022] As described above, since the melilite-type compound contains free oxide ions in the cage, it may function as an oxide ion conductor (Non-Patent Document 1).

[0023] However, according to the analysis by the inventors of the present application, it has been recognized that the ion conductivity of a general melilite-type compound having the above composition formula is not very high (for example, about 1 / 10 of YSZ).

[0024] ​Therefore, further measures are needed to apply meienite-type compounds to oxide ion-conducting solid electrolytes.

[0025] The inventors of this invention have been diligently researching and developing methods to improve the oxide ion conductivity of materials containing meienite-type compounds. They have discovered that a mixture of meienite-type compounds and cerium oxide (CeO2) exhibits high ionic conductivity, leading to the present invention. Therefore, the first solid electrolyte comprises a meienite-type compound and crystalline CeO2.

[0026] CeO2 has high oxide ion conductivity. Therefore, in the first solid electrolyte, the oxide ion conductivity can be increased by mixing a meienite-type compound with CeO2.

[0027] In this application, CeO2 is defined as a composition deficient in oxygen from its stoichiometric composition (for example, CeO 2―δ The composition may be (represented by ). Higher ionic conductivity is achieved by creating an oxygen-deficient state, i.e., by introducing oxygen vacancies. In addition, other metal elements may be added to CeO2 for the purpose of introducing oxygen vacancies.

[0028] The first solid electrolyte contains Ce in the CeO2 crystalline phase, but in addition, Ce may also be contained in the meienite-type compound. In this case, Ce may be positioned at the site of the Ca atom in the meienite-type compound.

[0029] When Ce is added to a meienite-type compound, it is possible to increase the oxide ion conductivity of the meienite-type compound itself. This, in turn, can further enhance the oxide ion conductivity of the first solid electrolyte.

[0030] Currently, the following reasons are considered to be the cause of increased ionic conductivity by including Ce in the meienite-type compound in one embodiment of the present invention.

[0031] When Ce is added to a meienite-type compound, the Ce atom is thought to preferentially substituted into the site of the Ca atom.

[0032] Here, the Ca atom is divalent, while the Ce atom is tetravalent. Therefore, when the Ca atom is substituted with the Ce atom, the concentration of oxide ions increases in order to maintain electrical neutrality. Consequently, the concentration of free oxide ions in the cage also increases, which is thought to improve ionic conductivity.

[0033] Ce is preferably contained in the first solid electrolyte in an amount of 80 mol% or less on the basis of CeO2, more preferably in the range of 1 mol% to 70 mol%, even more preferably in the range of 1 mol% to 20 mol%, and particularly preferably in the range of 2 mol% to 16 mol%.

[0034] Furthermore, if the Ce content in the first solid electrolyte is too high, the reduction resistance of the first solid electrolyte may decrease. However, by limiting the Ce content to 70 mol% or less in terms of CeO2 equivalent, such a decrease in reduction resistance can be suppressed.

[0035] Furthermore, the first solid electrolyte may also contain titanium (Ti).

[0036] Ti may be included in the first solid electrolyte in an amount ranging from 0.1 mol% to 30 mol% in terms of TiO2 relative to the total amount. In particular, the Ti content is preferably 8.1 mol% or more in terms of TiO2.

[0037] Furthermore, in the first solid electrolyte, Ti is considered to be substituted at the sites of aluminum (Al) atoms in the meienite-type compound. The molar ratio of Ti atoms to Al atoms, Ti / Al, may be 0.015 ≤ Ti / Al ≤ 0.50.

[0038] If the first solid electrolyte contains Ti, the ionic conductivity is further improved. This is expected to be due to the following reasons:

[0039] When Ti is added to a meienite-type compound, the Ti atoms are thought to preferentially substituted into the sites of the Al atoms. However, while Al atoms are trivalent, Ti atoms are tetravalent. Therefore, when an Al atom is substituted for a Ti atom, the concentration of oxide ions increases in order to maintain electrical neutrality. Consequently, the concentration of free oxide ions in the cage also increases, which is thought to improve ionic conductivity.

[0040] This first solid electrolyte exhibits significantly higher ionic conductivity compared to conventional meienite-type compounds. Therefore, the first solid electrolyte is expected to be used as a solid electrolyte in SOFCs and SOECs, among others.

[0041] (Application) The first solid electrolyte has significantly higher oxide ion conductivity. Therefore, the first solid electrolyte can be applied, for example, as a solid electrolyte in solid oxide fuel cell (SOFC) cells and as a solid electrolyte for SOECs.

[0042] Figure 1 schematically shows one example of an SOFC cell configuration.

[0043] As shown in Figure 1, the SOFC cell 100 has an oxygen electrode 110, a fuel electrode 120, and a solid electrolyte 130 between the two electrodes.

[0044] At oxygen electrode 110, for example, the following reactions occur: O2+4e - →2O 2- (1) Formula Oxide ions generated at the oxygen electrode 110 pass through the solid electrolyte 130 and reach the fuel electrode 120 on the opposite side. At the fuel electrode 120, for example, the following reactions occur: 2H2 + 2O 2- →2H2O+4e - Equation (2) Therefore, when the SOFC cell 100 is connected to the external load 140, the reactions in equations (1) and (2) continue, and power can be supplied to the external load 140.

[0045] In such an SOFC cell 100, a first solid electrolyte can be applied, for example, as the solid electrolyte 130.

[0046] In such an SOFC cell 100, the solid electrolyte 130 has significantly higher oxide ion conductivity, making it possible to obtain significantly higher power generation efficiency.

[0047] Figure 2 schematically shows one example of an SOEC cell configuration.

[0048] As shown in Figure 2, the SOEC cell 200 has an oxygen electrode 210, a fuel electrode 220, and a solid electrolyte 230 between the two electrodes.

[0049] At oxygen electrode 210, for example, the following reactions occur: 20 2- →O2+4e - (3) Formula Furthermore, at the fuel electrode 220, for example, the following reaction occurs: 2H2O + 4e - →2H2+2O 2- (4) Formula Oxide ions generated at the fuel electrode 220 pass through the solid electrolyte 230 and reach the oxygen electrode 210 on the opposite side. Therefore, when the SOEC cell 200 is connected to an external power supply 240, reactions (3) and (4) continue.

[0050] In such an SOEC cell 200, a first solid electrolyte can be applied as, for example, a solid electrolyte 230.

[0051] In such an SOEC cell 200, the solid electrolyte 230 has significantly higher oxide ion conductivity, making it possible to obtain significantly higher electrolysis efficiency.

[0052] An oxide ion-conducting solid electrolyte according to one embodiment of the present invention can be used as an "electrolyte layer" placed between two electrodes in such an electrochemical cell, as well as as an "electrolyte component" contained in the electrodes.

[0053] Furthermore, the solid electrolyte according to one embodiment of the present invention may be used in any form. For example, the solid electrolyte according to one embodiment of the present invention may be provided as a powder. Alternatively, the solid electrolyte according to one embodiment of the present invention may be mixed with a solvent and / or binder and provided in the form of a slurry, paste, or dispersion.

[0054] In addition to these, various other usage scenarios can be envisioned.

[0055] (Method for producing an oxide ion-conducting solid electrolyte according to one embodiment of the present invention) Next, with reference to Figure 3, an example of a method for producing an oxide ion-conducting solid electrolyte according to one embodiment of the present invention will be described.

[0056] Figure 3 schematically shows an example of a flow diagram of a method for producing an oxide ion-conducting solid electrolyte according to one embodiment of the present invention (hereinafter referred to as the "first manufacturing method").

[0057] As shown in Figure 3, the first manufacturing method is (1) A step of mixing a Ca source, an Al source, and cerium oxide in predetermined proportions to obtain a mixed powder (step S110), (2) A step of calcining the mixed powder to obtain calcined powder (step S120), (3) A step of sintering the calcined powder to obtain a sintered body (step S130), It has.

[0058] The following explains each step.

[0059] (Step S110) First, a mixed powder is prepared. For this purpose, a Ca source, an Al source, and cerium oxide are mixed in predetermined proportions.

[0060] The Ca source may be selected from, for example, metallic calcium, calcium carbonate, calcium oxide, calcium hydroxide, calcium nitrate, and calcium acetate.

[0061] The Al source may be selected from, for example, metallic aluminum, α-alumina, γ-alumina, aluminum hydroxide, aluminum nitrate, and aluminum sulfate.

[0062] The mixing method is not particularly limited, as long as a uniform mixed powder is obtained.

[0063] (Process S120) Next, the mixed powder is calcined.

[0064] The calcination process is performed to remove compounds such as carbonic acid and nitric acid contained in the mixed powder, thereby facilitating the formation of the desired meienite-type compound in the subsequent sintering process.

[0065] While there are no particular limitations on the calcination conditions, a calcination temperature of 1000°C or higher is preferable to obtain the desired mixed oxide. However, if the calcination temperature is too high, excessive crystallization will occur in the mixed powder. Therefore, a calcination temperature of 1300°C or lower is preferable.

[0066] The calcination time is, for example, around 5 to 24 hours. However, the calcination time also varies depending on the calcination temperature; the higher the calcination temperature, the shorter the calcination time can be.

[0067] This yields calcined powder.

[0068] The calcined powder may be ground as needed. The average particle size after grinding may be in the range of, for example, 0.1 μm to 100 μm.

[0069] (Step S130) Next, the calcined powder is sintered.

[0070] The sintering process is carried out to obtain a dense sintered body having the desired crystalline phase.

[0071] Alternatively, the calcined powder may be molded before the sintering process, and the resulting molded body may be used to carry out the sintering process.

[0072] The molding conditions are not particularly limited, and general molding methods such as uniaxial molding or hydrostatic molding may be employed.

[0073] The sintering method is not particularly limited; for example, the calcined powder or molded body may be sintered by a non-pressure sintering method under normal pressure.

[0074] Alternatively, the calcined powder may be sintered using a pressure sintering method such as hot press sintering or discharge plasma sintering. In this case, molding and sintering may be performed in a single process.

[0075] The sintering temperature is not particularly limited as long as a suitable sintered body is obtained, but a range of 1200°C to 1400°C is preferred. If the sintering temperature is too low, a dense sintered body may not be obtained. Conversely, if the sintering temperature is too high, melting of the material being processed may occur.

[0076] It is desirable to select the optimal sintering time according to the sintering temperature. Generally, the higher the sintering temperature, the shorter the time required for sintering to complete.

[0077] The optimal sintering time varies depending on the sintering temperature, but for non-pressure sintering, it is approximately 5 to 48 hours, while for pressure sintering using discharge plasma, it is approximately 5 to 60 minutes.

[0078] Furthermore, when using a carbon container for pressure sintering, carbon may adhere to the surface of the sintered body. In such cases, the attached carbon can be removed by heat treatment at 800°C to 1000°C for about 5 hours under atmospheric pressure.

[0079] By following the above steps, an oxide ion-conducting solid electrolyte according to one embodiment of the present invention can be manufactured.

[0080] (Another method for producing an oxide ion conductive solid electrolyte according to one embodiment of the present invention) Next, with reference to Figure 4, an example of another method for producing an oxide ion-conducting solid electrolyte according to one embodiment of the present invention will be described.

[0081] Figure 4 schematically shows an example of a flow chart of another method for producing an oxide ion conductive solid electrolyte according to one embodiment of the present invention (hereinafter referred to as the "second manufacturing method").

[0082] As shown in Figure 4, the second manufacturing method is (1) A step of mixing a Ca source and an Al source in a predetermined ratio to obtain a first mixed powder (step S210), (2) A step of calcining the first mixed powder to obtain the first calcined powder (step S220), (3) A step of mixing the first calcined powder and cerium oxide in a predetermined ratio to obtain a second mixed powder (step S230), (4) A step of calcining the second mixed powder to obtain the second calcined powder (step S240), (5) A step of sintering the second calcined powder to obtain a sintered body (step S250), It has.

[0083] Each step in the second manufacturing method can be easily understood by those skilled in the art from the description of steps S110 to S130 in the first manufacturing method described above. Therefore, a detailed explanation of each step is omitted here.

[0084] However, in the second manufacturing method, unlike the first manufacturing method, the oxide ion conductive solid electrolyte is produced through two calcination steps (steps S220 and S240).

[0085] In this case, compared to the first manufacturing method, where a mixed powder containing a Ca source, an Al source, and cerium oxide is calcined all at once, it is possible to produce an oxide ion-conducting solid electrolyte having a meienite-type compound and a crystalline phase of cerium oxide more reliably.

[0086] The method for producing an oxide ion-conducting solid electrolyte according to one embodiment of the present invention has been described above, with the first and second manufacturing methods as examples. However, the above description is merely an example, and the oxide ion-conducting solid electrolyte according to one embodiment of the present invention may be produced by other methods such as the hydrothermal method, the sol-gel method, and the liquid-phase combustion method. [Examples]

[0087] The following describes embodiments of the present invention.

[0088] In the following description, Examples 1 to 8 are examples, and Examples 21 to 22 are comparative examples.

[0089] (Example 1) The sintered body was fabricated using the following method.

[0090] [Mixing Process] Calcium carbonate powder (4.15g), α-alumina powder (2.52g), and cerium oxide powder (0.152g) were weighed separately. These were placed in a pot containing a φ5mm zirconia ball and 10cc of isopropanol, and the mixture was ground and mixed for 3 hours using a planetary ball mill. Next, the mixed powder was dried at 100°C to remove the isopropanol. Furthermore, the mixed powder was separated from the zirconia ball by sieving.

[0091] [Calibration process] The resulting mixed powder was placed in an alumina crucible and calcined in air at 1200°C for 5 hours. The resulting sample was ground in an agate mortar to prepare calcined powder.

[0092] [Sintering process] 1 g of calcined powder was placed in a φ1.5 cm carbide die, and uniaxial forming was performed by applying a pressure of 20 kN with a hydraulic press. Furthermore, hydrostatic forming was performed at 196 MPa to produce a φ1.5 cm pellet. The pellet was heat-treated in air at 1200°C for 12 hours to obtain a sintered body with a diameter of φ1.3 cm and a thickness of 2 mm.

[0093] The resulting sintered body is referred to as "Sample 1". In Sample 1, the Ce content is 1.3 mol% in terms of CeO2.

[0094] (Examples 2-6) A sintered body was prepared using the same method as in Example 1. However, in Examples 2 to 6, the mixing ratio of each raw material in the aforementioned [blending process] was changed from that in Example 1 to prepare the mixed powder. The other steps were the same as in Example 1.

[0095] The resulting sintered bodies will be referred to as "Sample 2" through "Sample 6," respectively.

[0096] (Example 7) A sintered body was prepared using the same method as in Example 1. However, in Example 7, in the aforementioned [mixing process], titanium dioxide powder was added as a raw material in addition to calcium carbonate powder, α-alumina powder, and cerium oxide powder. Titanium dioxide powder was added to a total of 5.1 mol%. The Ti / Al ratio in the mixed powder was 0.077.

[0097] The other steps are the same as in Example 1.

[0098] The resulting sintered body is referred to as "Sample 7".

[0099] (Example 8) A sintered body was prepared using the same method as in Example 7. However, in Example 8, the mixing ratio of each raw material was changed from that in Example 7 to prepare the mixed powder. The other steps were the same as in Example 7.

[0100] The resulting sintered body is referred to as "Sample 8".

[0101] (Example 21) A sintered body was prepared using the same method as in Example 1. However, in Example 21, in the aforementioned [mixing step], only calcium carbonate (4.33 g) and α-alumina (2.57 g) were mixed to prepare the mixed powder. That is, the mixed powder was prepared without adding cerium oxide powder. The other steps were the same as in Example 1.

[0102] The resulting sintered body is referred to as "Sample 21".

[0103] (Example 22) A sintered body was prepared using the same method as in Example 1. However, in Example 22, only cerium oxide powder was used to prepare the sintered body.

[0104] The resulting sintered body is referred to as "Sample 22".

[0105] Table 1 below summarizes the Ce and Ti content in each sample.

[0106] [Table 1] (evaluation) The following evaluations were performed using each sample.

[0107] (X-ray diffraction analysis) X-ray diffraction analysis was performed on each sample. A CeO2 crystal peak was observed in all samples except sample 21.

[0108] (Resistivity measurement) Resistivity measurements were performed on each sample. The impedance method was used for resistivity measurement.

[0109] First, the surface of each sample was polished with sandpaper ranging from #80 to #1000 to remove the surface layer and smooth the surface.

[0110] Next, a platinum electrode with a diameter of 6 mm and a thickness of 10 μm was placed on the polished surface via platinum paste. This sample was heat-treated at 1000°C for 15 minutes in an air atmosphere to solidify the platinum paste.

[0111] Next, the sample was placed in an electric furnace under an atmospheric environment. The sample was also connected to a potentogalvanostat (Biologic SP-150) via a platinum wire coupled to a platinum electrode.

[0112] Next, the sample was heated to 850°C and held for 120 minutes to stabilize its temperature.

[0113] After the sample temperature stabilized, impedance measurements were performed and a Cole-Cole plot was created. The measurement frequency was set from 1 MHz to 100 mHz.

[0114] In the resulting Cole-Cole plot, resistivity was calculated from the intersection points with the horizontal axis (real number axis).

[0115] Table 2 below summarizes the resistivity measurement results obtained for each sample.

[0116] [Table 2] In Table 2, the resistivity of each sample is shown as the relative resistivity, i.e., the ratio of the resistivity obtained in sample 21.

[0117] (Reduction resistance evaluation test) The reduction resistance was evaluated in some samples using the following method.

[0118] Each sample was placed in the furnace, and nitrogen gas was circulated at a flow rate of 30 mL / min. After maintaining the furnace at 900°C for 1 hour, it was slowly cooled, and each sample was collected.

[0119] The color change of the sample before and after testing was visually evaluated. If the sample color after testing was cream or light gray, the reduction resistance was judged as "A" (good). If the sample color after testing was gray, the reduction resistance was judged as "B" (average). Furthermore, if the sample color after testing was black, the reduction resistance was judged as "C" (poor).

[0120] Table 3 below summarizes the reduction resistance evaluation test results obtained for each sample.

[0121] [Table 3] These results show that samples 1-5 and samples 7-8 exhibited significantly lower resistivity compared to sample 21. Furthermore, samples 3-4 and sample 6 were found to have significantly higher reduction resistance compared to sample 22.

[0122] (One aspect of the present invention) The present invention may have the following embodiments.

[0123] (Aspect 1) A solid electrolyte that conducts oxide ions, Ca 12 Al 14 O 33 A meienite-type compound having a representative composition represented by the following: The crystalline phase of cerium oxide (CeO2), A solid electrolyte having oxide ion conductivity.

[0124] (Aspect 2) The oxide ion conductive solid electrolyte according to embodiment 1, wherein the myenite-type compound contains cerium (Ce).

[0125] (Aspect 3) An oxide ion conductive solid electrolyte according to Embodiment 1, containing 2 mol% to 16 mol% of Ce in terms of CeO2.

[0126] (Aspect 4) Furthermore, the oxide ion conductive solid electrolyte according to any one of embodiments 1 to 3, further comprising titanium (Ti) in an amount of 0.1 mol% to 30 mol% in terms of TiO2.

[0127] (Appendix 5) The oxide ion conductive solid electrolyte according to embodiment 4, wherein the Ti is located at the site of the Al atom in the meienite-type compound.

[0128] (Aspect 6) An electrochemical device comprising an oxide ion-conducting solid electrolyte according to any one of embodiments 1 to 5.

[0129] This application claims priority based on Japanese Patent Application No. 2021-182099, filed on 8 November 2021, and the entire contents of the said Japanese application are incorporated herein by reference. [Explanation of Symbols]

[0130] 100 SOFC cells 110 Oxygen electrode 120 Fuel electrode 130 Solid electrolyte 140 External load 200 SOEC cells 210 Oxygen electrode 220 Fuel electrode 230 Solid electrolyte 240 External power supply

Claims

1. A solid electrolyte that conducts oxide ions, Ca １２ Al １４ O ３３ A meienite-type compound having a representative composition represented by the following: Cerium oxide (CeO ２ ) and the crystalline phase, A solid electrolyte having oxide ion conductivity.

2. The oxide ion conductive solid electrolyte according to claim 1, wherein the myenite-type compound contains cerium (Ce).

3. CEO ２ The oxide ion conductive solid electrolyte according to claim 1, comprising 2 mol% to 16 mol% of Ce in conversion.

4. Furthermore, titanium (Ti) is TiO ２ A solid electrolyte that conducts oxide ions according to claim 1 or 2, containing 0.1 mol% to 30 mol% in conversion.

5. The oxide ion conductive solid electrolyte according to claim 4, wherein the Ti is located at the site of the Al atom in the meienite-type compound.

6. An electrochemical device comprising an oxide ion conductive solid electrolyte according to claim 1 or 2.

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