Proton conducting electrolyte powder, proton conducting electrolyte membrane, and preparation method thereof

Abstract

The present invention relates to a proton conducting electrolyte powder, an electrolyte membrane, and a preparation method thereof. Specifically, the present invention relates to a heterophasic BCZYYb proton conducting electrolyte powder obtained using low-temperature solid synthesis at 1000 to 1200°C, a proton conducting electrolyte membrane with a monophasic BCZYYb (Ba,Ce,Zr,Y,Yb) composition prepared by sintering the proton conducting electrolyte powder at 1300 to 1500°C, and a preparation method of the proton conducting electrolyte membrane, comprising calcining and sintering at the temperature.

Description

Proton-conducting electrolyte powder, proton-conducting electrolyte membrane and method for producing the same

[0001] The present invention relates to a proton-conducting electrolyte powder, an electrolyte membrane, and a method for producing the same. Specifically, the present invention relates to a heterogeneous BCZYYb proton-conducting electrolyte powder obtained by a low-temperature solid-state synthesis method at 1000 to 1200°C, a single-phase BCZYYb (Ba, Ce, Zr, Y, Yb) composition proton-conducting electrolyte membrane produced by sintering the powder at 1300 to 1500°C, and a method for producing the proton-conducting electrolyte membrane comprising a process of calcining and sintering at the above temperatures.

[0002] Electrochemical cells, including fuel cells and water electrolytic cells, use proton-conducting oxides as electrolytes, and specifically, Ba(Ce,Zr)O3 electrolytes having an ABO3 structure, in which Y (yttrium) and / or Yb (ytterbium) is doped at the B-site, are used. When forming the proton-conducting oxide material, high temperatures are required in the calcination process for phase synthesis or the sintering process for forming a dense structure due to its refractory properties.

[0003] Previously, proton-conducting oxide electrolytes were formed mainly using solid-state synthesis methods that performed calcination and sintering processes at temperatures above 1400℃. However, during the calcination and sintering processes under the above high-temperature conditions, some of the Ba (barium) in the electrolyte volatilizes, forming a proton-conducting oxide electrolyte that does not satisfy the stoichiometric ratio. When an electrochemical cell is manufactured by introducing a proton-conducting oxide electrolyte with such a non-stoichiometric composition, the stability of the electrolyte phase decreases, causing the formation of a secondary phase, and ionic conductivity may also decrease, which may deteriorate the performance of the cell. In addition, the high-temperature calcination and sintering processes may cause phase separation, which may be more severe as the dopant located at the B-site of the ABO3 structure is precipitated, resulting in a deterioration in the electrochemical performance and stability of the cell.

[0004] Therefore, in order to secure the performance and stability of an electrochemical cell, a proton-conducting oxide electrolyte satisfying the stoichiometric ratio and a method for manufacturing the same are very necessary. Specifically, a proton-conducting oxide electrolyte that can be manufactured at a temperature range lower than the temperature described above and a method for manufacturing the same are required.

[0005]

[0006] The technical problem to be solved by the present invention is to provide a proton conductive electrolyte powder that satisfies the stoichiometric ratio by suppressing the volatilization of barium without including barium carbonate by calcining the raw material at a lower temperature than the prior art.

[0007] Another technical problem to be solved by the present invention is to provide a proton conductive electrolyte membrane having high density and uniform distribution of electrolyte components, thereby providing high stability and ionic conductivity, by sintering the aforementioned proton conductive electrolyte powder at 1300 to 1500°C.

[0008] Another technical problem to be solved by the present invention is to provide a method for manufacturing a proton-conducting oxide electrolyte membrane having the aforementioned advantages.

[0009] A proton conductive electrolyte powder according to one embodiment of the present invention includes a powder in which at least two different phases of BCZYYb oxides represented by the following chemical formula 1 are mixed, and the mixed powder may include Ce-rich BCZYYb oxide and Zr-rich BCZYYb oxide.

[0010] [Chemical Formula 1]

[0011] Ba x Ce a Zr b Y γ Yb δ O 3-r (However, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1.)

[0012] According to another embodiment of the present invention, a proton conductive electrolyte membrane is an electrolyte membrane manufactured by sintering the above-described proton conductive electrolyte powder at 1300°C to 1500°C, wherein the electrolyte membrane may include a single-phase BCZYYb oxide represented by the following chemical formula 1.

[0013] [Chemical Formula 1]

[0014] Ba x Ce a Zr b Y γ Yb δ O 3-r (However, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1.)

[0015] A method for manufacturing a proton conductive electrolyte membrane according to another embodiment of the present invention may include a step of preparing a raw material; a step of first heat-treating the raw material at a temperature of 1000°C to 1200°C to obtain a proton conductive electrolyte powder; and a step of forming a proton conductive electrolyte membrane by applying the electrolyte powder to an electrode and then second heat-treating it at a temperature of 1300°C to 1500°C.

[0016]

[0017] The present invention can provide a proton conductive electrolyte powder that suppresses volatilization of barium without including barium carbonate, satisfies the stoichiometric ratio, and can form a dense film even at a lower temperature than the prior art.

[0018] The present invention can provide a proton-conducting electrolyte membrane having high density and uniform distribution of electrolyte components, thereby having high stability and ionic conductivity, and can improve electrochemical performance when the electrolyte membrane is applied to an electrochemical cell.

[0019] The present invention can provide a method for manufacturing a proton conductive electrolyte membrane that satisfies the stoichiometric ratio and has high stability and ionic conductivity by suppressing volatilization of barium through a process of calcining a raw material at 1000 to 1200°C and sintering the obtained electrolyte powder at 1300 to 1500°C.

[0020] Figure 1 shows the XRD analysis results of the proton conductive electrolyte powder of Example 1 obtained by calcining the raw material at 1100°C.

[0021] Figure 2 shows the results of XRD analysis of the proton conductive electrolyte membrane of Example 1 obtained by calcining the proton conductive electrolyte powder at 1100°C and then sintering it at 1400°C.

[0022] Figure 3 is a graph comparing the molar ratio of Ba (barium) content of raw material mixed powder and proton conductive electrolyte powder according to examples and comparative examples.

[0023] Figure 4 shows SEM images of the surface of a proton conductive electrolyte membrane according to a comparative example at different sintering temperatures.

[0024] Figure 5 shows SEM images of the surface of a proton conductive electrolyte membrane according to an embodiment at different sintering temperatures.

[0025] Figure 6 shows the results of cross-sectional EDS (Energy Disperse X-ray spectroscopy) mapping analysis of a proton conductive electrolyte membrane and a fuel electrode laminated sintered body according to a comparative example.

[0026] Figure 7 shows the results of cross-sectional EDS (Energy Disperse X-ray spectroscopy) mapping analysis of a proton conductive electrolyte membrane and a fuel electrode laminated sintered body according to an embodiment.

[0027] Figure 8 shows an IVP curve comparing the electrochemical performance of a fuel cell to which a proton conductive electrolyte membrane according to an example and a comparative example is applied.

[0028] Figure 9 shows the impedance comparing the electrochemical characteristics of fuel cells to which proton conductive electrolyte membranes according to examples and comparative examples are applied.

[0029]

[0030] In this specification, terms such as first, second, and third are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0031] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless specifically stated otherwise.

[0032] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention. As used herein, the singular forms "a," "an," and "the" include plural forms as well, unless the context clearly dictates otherwise. The term "comprising," as used herein, specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0033] In this specification, the term "combination of these" included in the expression in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expression in the Makushi format, and means including one or more selected from the group consisting of the components.

[0034] In this specification, when a part is referred to as being "on" or "over" another part, it may be directly on or over the other part, or there may be other parts intervening therebetween. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening therebetween.

[0035] In this specification, D10 means the particle size at 10% by volume in the cumulative size-distribution curve, D50 means the particle size at 50% by volume, D90 means the particle size at 90%, and D99 means the particle size at 99%.

[0036] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0037] Also, unless otherwise stated, % means weight%, and 1 ppm is 0.0001 weight%.

[0038] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0039] Hereinafter, a proton conductive electrolyte powder according to one embodiment of the present invention will be described.

[0040] A proton conductive electrolyte powder according to one embodiment includes a powder in which at least two different phases of BCZYYb oxides represented by the following chemical formula 1 are mixed, and the mixed powder may include Ce-rich BCZYYb oxide and Zr-rich BCZYYb oxide.

[0041] [Chemical Formula 1]

[0042] Ba x Ce a Zr b Y γ Yb δ O 3-r (However, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1.)

[0043] When the proton conductive electrolyte powder satisfies the above chemical formula 1, a uniform single-phase electrolyte film with high chemical stability and ionic conductivity can be formed.

[0044] In one embodiment, the proton conductive electrolyte powder may have a value of x / (a+b+γ+δ) in the chemical formula 1 within a range of 0.94 to 1.

[0045] When the value of x / (a+b+γ+δ) is within the above-mentioned range, the proton conductive electrolyte powder satisfies the stoichiometric ratio, and thus, precipitation of dopants Y and / or Yb does not occur, thereby forming a stable electrolyte film. On the other hand, when the value of x / (a+b+γ+δ) is less than the lower limit of the above-mentioned range, barium is excessively volatilized during formation of the electrolyte powder, resulting in a stoichiometric imbalance, and phase separation may occur in the electrolyte powder.

[0046] In the proton conductive electrolyte powder according to one embodiment, the molar ratio (number of moles of Ce-rich oxide: number of moles of Zr-rich oxide) of the mixed Ce-rich oxide and Zr-rich oxide may be 1:7 to 7:1 depending on the final composition of the desired proton conductive electrolyte.

[0047] When the molar ratio of the Ce-rich oxide and the Zr-rich oxide is within the above-mentioned range, an electrolyte membrane that ensures ionic conductivity and chemical stability can be formed when the electrolyte powder is sintered. On the other hand, when the molar ratio is below the lower limit of the above-mentioned range, stability can be secured when manufacturing the electrolyte membrane, but a problem of reduced ionic conductivity may occur, and when the molar ratio exceeds the upper limit of the above-mentioned range, ionic conductivity is secured, but a problem of reduced stability of the electrolyte membrane may occur.

[0048] The proton conductive electrolyte powder according to one embodiment may not contain BaCO3.

[0049] When the proton conductive electrolyte powder contains BaCO3, when an electrolyte film is formed on a fuel electrode, the BaCO3 may cause a side reaction with another compound, making it difficult to form a single-phase electrolyte film, and may deteriorate the electrochemical performance of the formed electrolyte film.

[0050] In a proton conductive electrolyte powder according to one embodiment, the average particle diameter (D50) of the mixed powder may be within a range of 0.05 ㎛ to 0.5 ㎛.

[0051] When the average particle size of the above-mentioned mixed powder is within the above-mentioned range, when the above-mentioned mixed powder is laminated on a fuel electrode and then simultaneously sintered, a uniform single-phase electrolyte membrane can be formed. On the other hand, when the average particle size of the above-mentioned mixed powder is not within the above-mentioned range, the synthesis reaction between Ce-rich BCZYYb oxide and Zr-rich BCZYYb oxide may be partially inhibited during sintering, and thus, it may be difficult to form a uniform single-phase electrolyte membrane.

[0052] In a proton conductive electrolyte powder according to one embodiment, the BET specific surface area of ​​the mixed powder is 1 m 2 / g to 15 m 2 / g can be included in the range.

[0053] When the BET specific surface area of ​​the above-mentioned mixed powder is within the above-mentioned range, a uniform single-phase electrolyte film can be formed when the above-mentioned mixed powder is laminated on a fuel electrode and then simultaneously sintered. On the other hand, when the BET specific surface area of ​​the above-mentioned mixed powder is below the lower limit of the above-mentioned range, some unreacted substances may be generated when the electrolyte film is formed by sintering.

[0054] Hereinafter, a proton conductive electrolyte membrane according to another embodiment of the present invention will be described.

[0055] A proton conductive electrolyte membrane according to another embodiment is an electrolyte membrane manufactured by sintering the above-described proton conductive electrolyte powder at 1300°C to 1500°C, and the electrolyte membrane may include a single-phase BCZYYb oxide represented by the following chemical formula 1.

[0056] [Chemical Formula 1]

[0057] Ba x Ce a Zr b Y γ Yb δ O 3-r (However, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1.)

[0058] In a proton conductive electrolyte membrane according to another embodiment, when XRD (X-ray diffraction) analysis is performed on the electrolyte membrane, one peak may be generated in each of the sections where 2θ (theta) is 28° to 30°, 35° to 37°, 41° to 43°, 51° to 53°, 60° to 62°, 68° to 70°, and 76° to 78°.

[0059] When analyzing the XRD of the above electrolyte membrane, if multiple peaks occur in some of the sections of the above-mentioned 2θ, it can be recognized that a secondary phase exists, and if a secondary phase exists, the ionic conductivity of the electrolyte membrane may be reduced.

[0060] A proton conductive electrolyte membrane according to another embodiment may be characterized in that at least one element selected from Y and Yb is not precipitated in the electrolyte membrane.

[0061] When Y and / or Yb dopants are deposited on the electrolyte, the Ba, Ce, Zr, Y, and / or Yb elements that make up the electrolyte may be unevenly distributed, which may accelerate phase separation. This may cause the electrolyte on the proton-conducting oxide to react with CO2 in the atmosphere, causing a decomposition reaction to produce BaCO3, which may deteriorate cell stability and electrochemical performance.

[0062] The area-specific resistance of the proton-conducting electrolyte membrane according to another embodiment is 0.005 Ω·cm per 1 ㎛ of electrolyte membrane thickness. 2 0.02 Ω·cm 2 It could be a range.

[0063] The surface resistance of the above electrolyte membrane can be achieved by applying a lower sintering temperature compared to conventional proton conductive electrolyte membrane manufacturing methods.

[0064] A proton conductive electrolyte membrane according to another embodiment may have a porosity in the range of 0% to 5%.

[0065] The above porosity can be achieved by applying a lower sintering temperature than conventionally used porosity, and when the above porosity satisfies the above-mentioned range, the electrochemical performance of the electrolyte can be improved.

[0066] Hereinafter, a method for manufacturing a proton conductive electrolyte membrane according to another embodiment of the present invention will be described.

[0067] A method for manufacturing a proton conductive electrolyte membrane according to another embodiment may include a step of preparing a raw material; a step of first heat-treating the raw material at a temperature of 1000°C to 1200°C to obtain a proton conductive electrolyte powder; and a step of forming a proton conductive electrolyte membrane by applying the electrolyte powder to an electrode and then second heat-treating it at a temperature of 1300°C to 1500°C.

[0068] The above first heat treatment temperature may preferably be 1000°C to 1200°C. More preferably, it may be 1050°C to 1150°C. Even more preferably, it may be 1050°C to 1100°C. Even more preferably, it may be 1100°C.

[0069] When the first heat treatment temperature is within the above-mentioned range, the unreacted BaCO3 phase can be removed to prevent side reactions with other compounds. In addition, by suppressing the volatilization of barium, an electrolyte powder satisfying the stoichiometric ratio can be formed. In addition, since an electrolyte powder having two or more compositions while including a composition that is relatively easy to sinter can be formed, the second heat treatment temperature can be lowered to 1400°C or lower when manufacturing an electrolyte membrane with high density. On the other hand, when the first heat treatment temperature exceeds the upper limit of the above-mentioned range, the volatilization of barium can be promoted, thereby forming an electrolyte powder that does not satisfy the stoichiometric ratio. In addition, when the volatilization of barium is aggravated, a dopant of Y or Yb can be precipitated, which can cause phase separation. When phase separation of the electrolyte occurs, the electrochemical performance and stability of a fuel cell introducing the same can be deteriorated.

[0070] The second heat treatment temperature may preferably be 1350°C to 1500°C. More preferably, it may be 1350°C to 1400°C. Even more preferably, it may be 1400°C.

[0071] When the second heat treatment temperature falls within the aforementioned range, the impedance of the manufactured dense electrolyte membrane can be reduced, thereby improving the electrochemical performance of the fuel cell. On the other hand, when the second heat treatment temperature exceeds the upper limit of the aforementioned range, cell damage due to high-temperature deterioration can occur.

[0072] In a method for manufacturing a proton conductive electrolyte membrane according to another embodiment, the raw material preparation step may include mixing BaCO3, CeO2, and ZrO2, and additionally mixing at least one selected from among Y2O3, Yb2O3, YbO, In2O3, Sc2O3, Pr2O3, and HfO2 as a dopant raw material.

[0073] Although the above type of raw material has been applied in the embodiments of the present invention, the present invention is not limited thereto.

[0074] In another embodiment, in a method for manufacturing a proton conductive electrolyte membrane, the raw material preparation step comprises BaCO3 mol (m BaCO3 ) for ZrO2(m ZrO2 ) may include mixing in a molar ratio of 1:0.1 to 1:0.8.

[0075] In another embodiment, in a method for manufacturing a proton conductive electrolyte membrane, the raw material preparation step comprises BaCO3 mol (m BaCO3 ) for CeO2(m CeO2 ) may include mixing in a molar ratio of 1:0.1 to 1:0.8.

[0076] In another embodiment, in a method for manufacturing a proton conductive electrolyte membrane, the raw material preparation step comprises BaCO3 mol (m BaCO3 ) of dopant raw materials It may include mixing at a molar ratio of 1:0.1 to 1:0.2.

[0077] When the weight ratio of the above BaCO3, CeO2, ZrO2 and dopant raw materials is within the above-mentioned range, a proton conductive electrolyte powder and electrolyte membrane having both balanced and improved ionic conductivity and stability can be manufactured.

[0078] In the raw material preparation step of the method for manufacturing a proton conductive electrolyte membrane according to another embodiment, the average particle diameter (D50) of the ZrO2 powder may be in the range of 20 nm to 100 nm.

[0079] When the average particle diameter (D50) of the ZrO2 powder is within the above-mentioned range, the electrolyte powder according to the embodiment of the present invention can be smoothly synthesized. On the other hand, when the average particle diameter (D50) of the ZrO2 powder is less than the lower limit of the above-mentioned range, aggregates may occur during the raw material powder mixing step, and when the degree of occurrence is severe, an electrolyte powder that does not satisfy the stoichiometric ratio may be formed. When the average particle diameter (D50) of the ZrO2 powder exceeds the upper limit of the above-mentioned range, an unreacted ZrO2 phase may remain during the same heat treatment process.

[0080] In a method for manufacturing a proton conductive electrolyte membrane according to another embodiment, the time for performing the first heat treatment in the electrolyte powder obtaining step may be in the range of 1 hour to 24 hours.

[0081] When the time for performing the first heat treatment is within the above-mentioned range, a proton conductive electrolyte powder can be formed in which the BaCO3 unreacted phase is completely removed while suppressing volatilization of barium.

[0082] In a method for manufacturing a proton conductive electrolyte membrane according to another embodiment, the time for performing the second heat treatment in the electrolyte membrane forming step may be in the range of 1 hour to 24 hours.

[0083] When the time for performing the second heat treatment is within the above-mentioned range, an electrolyte powder having two or more compositions can be manufactured into a single-phase dense electrolyte membrane.

[0084] Hereinafter, preferred manufacturing examples, examples, comparative examples, and experimental examples according to the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0085] Example 1 - First heat treatment: 1100℃ / Second heat treatment: 1400℃

[0086] As raw materials, BaCO3100.0g, CeO225.0g, ZrO234.9g, Y2O35.7g, Yb2O310.0g were weighed and mixed, and then ethanol and a dispersant were added, and ball milled with 5pi zirconia balls for 24 hours. Afterwards, the raw material mixture was dried in an oven at 120℃ to remove ethanol. The raw material mixture was then placed in a 35pi mold and pressurized at 20㎫. Then, the raw material mixture was put into a kiln, subjected to a primary heat treatment at 1100℃ for 10 hours, ball milled with 5pi zirconia balls for 24 hours, and sieved with a 100㎛ mesh sieve to obtain a proton-conducting BCZYYb electrolyte powder. The obtained BCZYYb powder was dispersed in ethanol to form an electrolyte paste, and the paste was screen-printed on a fuel electrode layer to laminate an electrolyte layer having a thickness of 15 μm. Thereafter, the laminate (electrolyte layer-fuel electrode layer) was placed in a kiln and subjected to a secondary heat treatment at a temperature of 1400°C for 4 hours to produce a dense proton-conducting electrolyte membrane.

[0087] Example 2 - First heat treatment: 1100℃ / Second heat treatment: 1500℃

[0088] A proton conductive electrolyte membrane was manufactured using the same process as Example 1, except that the second heat treatment temperature was adjusted to 1500°C.

[0089] Comparative Example 1 - First heat treatment: 1400℃ / Second heat treatment: 1500℃

[0090] A proton conductive electrolyte membrane was manufactured using the same process as Example 1, except that the first heat treatment temperature was adjusted to 1400°C and the second heat treatment temperature was adjusted to 1500°C.

[0091] Comparative Example 2 - First heat treatment: 1400℃ / Second heat treatment: 1400℃

[0092] A proton conductive electrolyte membrane was manufactured using the same process as Example 1, except that the first heat treatment temperature was adjusted to 1400°C and the second heat treatment temperature was adjusted to 1400°C.

[0093] Experimental Example 1 - XRD Analysis

[0094] Figure 1 shows the XRD analysis results of the proton conductive electrolyte powder of Example 1 obtained by calcining the raw material at 1100°C.

[0095] Figure 2 shows the results of XRD analysis of the proton conductive electrolyte membrane of Example 1 obtained by calcining the proton conductive electrolyte powder at 1100°C and then sintering it at 1400°C.

[0096] According to the above drawing 1, when a barium source, a cerium source, a zirconia source, a yttrium source, and a ytterbium source were mixed and a first heat treatment was performed at 1100℃, which is a lower temperature than the conventional process, it was confirmed that two peaks, Ce-rich BCZYYb and Zr-rich BCZYYb, were generated. Since no other peaks were generated other than these two peaks, it can be seen that there are no unreacted raw materials, including the barium source BaCO3, and that all of the introduced raw materials participated in the reaction to form a BCZYYb phase having a composition that satisfies the stoichiometric ratio.

[0097] According to the above Fig. 2, when the electrolyte powder obtained by the first heat treatment at 1100℃ was laminated on the fuel electrode and the second heat treatment (simultaneous sintering) was performed, it was confirmed that a single-phase BCZYYb electrolyte membrane was manufactured. Although a sintering aid that facilitates sintering was not separately added in the present invention, since a BCZYYb electrolyte having a composition that facilitates sintering is formed during the first heat treatment, it can be inferred that a single-phase BCZYYb membrane can sufficiently be formed even at 1400℃.

[0098] Experimental Example 2 - Electrolyte Element Composition Analysis & EDS Mapping

[0099] Figure 3 is a graph comparing the molar ratio of Ba (barium) content of raw material mixed powder and proton conductive electrolyte powder according to examples and comparative examples.

[0100] Figure 6 shows the results of cross-sectional EDS (Energy Disperse X-ray spectroscopy) mapping analysis of a proton conductive electrolyte membrane and a fuel electrode laminated sintered body according to a comparative example.

[0101] Figure 7 shows the results of cross-sectional EDS (Energy Disperse X-ray spectroscopy) mapping analysis of a proton conductive electrolyte membrane and a fuel electrode laminated sintered body according to an embodiment.

[0102] According to the above Figure 3, it was confirmed that the molar content of Ba confirmed in the electrolyte powder of Example 1 almost matches the molar content of Ba included in the raw material mixture powder. That is, in Example 1, since almost no loss of Ba occurs, it can be inferred that a proton conductive electrolyte powder satisfying the stoichiometric ratio is formed. On the other hand, in the electrolyte of Comparative Example 1, it was confirmed that the loss rate of Ba was about 7 mol% compared to the composition of the raw material mixture powder before synthesis, and since an electrolyte that does not satisfy the stoichiometric ratio is generated, it can be inferred that the stability is inferior to that of the electrolyte of Example 1.

[0103] According to the above FIGS. 6 and 7, it can be confirmed that the electrolyte membrane of Example 1 confirmed in FIG. 7 has uniformly distributed constituent elements. On the other hand, it can be confirmed that the electrolyte membrane of Comparative Example 1 confirmed in FIG. 6 contains precipitates of dopants Y and Yb.

[0104] Experimental Example 3 - SEM Analysis

[0105] Figure 4 shows SEM images of the surface of a proton conductive electrolyte membrane according to a comparative example at different sintering temperatures.

[0106] Figure 5 shows SEM images of the surface of a proton conductive electrolyte membrane according to an embodiment at different sintering temperatures.

[0107] According to the above drawing 4, the electrolyte of Comparative Example 2, which was subjected to the first heat treatment at 1400°C and then the second heat treatment at 1400°C, had small grain sizes, pores were observed in some parts of the electrolyte membrane, and low density was observed. The electrolyte membrane of Comparative Example 1, which was subjected to the first heat treatment at 1400°C and then the second heat treatment at 1500°C, had increased grain sizes and improved density compared to the electrolyte of Comparative Example 2.

[0108] According to the above Fig. 5, it was confirmed that the electrolyte membrane of Example 1, which was subjected to the first heat treatment at 1100°C and then the second heat treatment at 1400°C, had a high density although the grain size was not large. It was confirmed that the electrolyte membrane of Example 2, which was subjected to the first heat treatment at 1100°C and then the second heat treatment at 1500°C, had an increased grain size and a high density compared to Example 1.

[0109] Experimental Example 4 - Electrochemical Performance Analysis (Power Density and Resistance Comparison)

[0110] Figure 8 shows an IVP curve comparing the electrochemical performance of a fuel cell to which a proton conductive electrolyte membrane according to an example and a comparative example is applied.

[0111] Figure 9 shows the impedance comparing the electrochemical characteristics of fuel cells to which proton conductive electrolyte membranes according to examples and comparative examples are applied.

[0112] The above figures 8 and 9 are the same air electrode PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ(PBSCF) Electrochemical characteristics of a fuel cell manufactured by dispersing powder in ethanol to form an air electrode paste, screen printing the paste on an electrolyte layer, and then placing it in a kiln and heat-treating it at a temperature of 950°C for 5 hours.

[0113] According to the above FIGS. 8 and 9, it can be confirmed that the fuel cell to which the electrolyte membrane of Example 1, which was subjected to low-temperature calcination, was applied has a higher power density and lower ohmic resistance and polarization resistance than the fuel cell to which the electrolyte membrane of Comparative Example 1 was applied. The electrolyte membrane according to the example showed a density similar to that of the conventional process despite being manufactured by the low-temperature calcination process. In addition, since the volatilization of barium is suppressed and the unreacted phase of the raw material does not exist, no side reaction of unreacted substances occurs during the secondary heat treatment, so that an electrolyte membrane in which elements are uniformly distributed is formed, and thus the resistance is reduced and the ionic conductivity is improved, it can be judged that the power density is higher than that of the fuel cell to which the electrolyte membrane of Comparative Example 1 was applied by the conventional process.

Claims

1. A powder comprising a mixture of BCZYYb oxides having at least two different phases represented by the following chemical formula 1, The above mixed powder comprises Ce-rich BCZYYb oxide and Zr-rich BCZYYb oxide. Proton conducting electrolyte powder. [Chemical Formula 1] They x Ce a Zr b Y γ Yb δ YOU ARE 3-r (So, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1 Fig.) 2. In paragraph 1, In the above chemical formula 1, The value of the above x / (a+b+γ+δ) is between 0.94 and 1, Proton conducting electrolyte powder.

3. In paragraph 1, The molar ratio of the above mixed Ce-rich oxide and Zr-rich oxide (number of moles of Ce-rich oxide: number of moles of Zr-rich oxide) is 1:7 to 7:

1. Proton conducting electrolyte powder.

4. In paragraph 1, BaCO 3 Not including, Proton conducting electrolyte powder.

5. In paragraph 1, The average particle size (D50) of the above mixed powder is 0.05 ㎛ to 0.5 ㎛. Proton conducting electrolyte powder.

6. In paragraph 1, The BET surface area of ​​the above mixed powder is 1 m 2 / g to 15 m 2 / g person, Proton conducting electrolyte powder.

7. In an electrolyte membrane manufactured by sintering the proton conductive electrolyte powder according to one of claims 1 to 6 at 1300°C to 1500°C, The above electrolyte membrane is a single-phase BCZYYb oxide represented by the following chemical formula 1. Proton conducting electrolyte membrane. [Chemical Formula 1] They x Ce a Zr b Y γ Yb δ YOU ARE 3-r (So, x / (a+b+γ+δ)≤1 a+b+γ+δ=1, 0.1≤a≤0.7, 0.1≤b≤0.7, 0≤γ≤0.2, 0≤δ≤0.2, 0≤r≤1 Fig.) 8. In paragraph 7, When XRD (X-ray diffraction) analysis was performed on the above electrolyte membrane, one peak occurred in each section where 2θ (theta) was 28°~30°, 35°~37°, 41°~43°, 51°~53°, 60°~62°, 68°~70°, and 76°~78°. Proton conducting electrolyte membrane.

9. In paragraph 7, The above proton conductive electrolyte membrane is characterized in that at least one element selected from Y and Yb is not precipitated in the electrolyte membrane. Proton conducting electrolyte membrane.

10. In paragraph 7, The area-specific resistance of the above electrolyte membrane is 0.005 Ω cm per 1 ㎛ of electrolyte membrane thickness. 2 Within 0.02 Ω cm 2 person, Proton conducting electrolyte membrane.

11. In paragraph 7, With porosity of 0% to 5%, Proton conducting electrolyte membrane.

12. Raw material preparation stage; A step of obtaining a proton conductive electrolyte powder by first heat treating the above raw material at a temperature of 1000℃ to 1200℃; and A step of forming a proton conductive electrolyte film by applying the electrolyte powder to the electrode and then performing a second heat treatment at a temperature of 1300°C to 1500°C; A method for producing a proton conducting oxide electrolyte membrane.

13. In paragraph 12, The raw material preparation step is BaCO 3 Powder, CeO 2 Powder, ZrO 2 Mix the powder, Y in powder form as a dopant raw material 2 O 3 , Yb 2 O 3 , YbO, In 2 O 3 , Sc 2 O 3 , Pr 2 O 3 , HfO 2 Including additionally mixing one or more selected from among A method for producing a proton conducting oxide electrolyte membrane.

14. In paragraph 13, In the raw material preparation stage, the above ZrO 2 The average particle size (D50) of the powder is 20 nm to 100 nm. A method for producing a proton conducting oxide electrolyte membrane.

15. In paragraph 12, The time for performing the first heat treatment in the electrolyte powder obtaining step is in the range of 1 hour to 24 hours. A method for producing a proton conducting oxide electrolyte membrane.

16. In paragraph 12, The time for performing the second heat treatment in the electrolyte membrane formation step is in the range of 1 hour to 24 hours. A method for producing a proton conducting oxide electrolyte membrane.

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