KR20150104745A - Electrolytic composition for solid oxide fuel cell and solid oxide fuel cell - Google Patents

Abstract

Provided are an electrolytic composition for a solid oxide fuel cell, and a solid oxide fuel cell. The electrolytic composition for the solid oxide fuel cell has high conductivity in a broad temperature range, and is capable of giving excellent output properties to the solid oxide fuel cell. The electrolytic composition of the present invention, as a scandium oxide stabilization frequency zirconium oxide-based electrolytic composition, contains a compound represented by chemical formula of (ZrO_2)_(1-x-a)(Sc_2O_3)_x(M_2O_3)_a. In the chemical formula, x is 0.09 <= x <= 0.11 meanwhile a is 0 < a <= 0.025 and M is one or more elements among Sm and Nd. The conductivity of the compound is greater than or equal to 1.4 × 10^(-2) (S/cm) at 600°C; the output density is greater than or equal to 25.0 (mW/cm^2) at 600°C; and the compound does not show a phase transition from a cubic phase to a rhombohedral phase at a temperature range of 25 to 850°C.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolyte composition for a solid oxide fuel cell and a solid oxide fuel cell,

The present invention relates to an electrolyte composition usable as a solid electrolyte of a solid oxide fuel cell, particularly a scandium oxide stabilized zirconium oxide-based electrolyte composition, and a solid oxide fuel cell using the electrolyte composition.

Solid Oxide Fuel Cells (SOFCs) are known to be more efficient than other types of fuel cells. Therefore, SOFC is attracting attention because it can build a new power generation system that can use energy efficiently, and the development thereof is actively progressed recently.

The SOFC comprises a single cell structure having a fuel electrode on one side of the solid electrolyte and an air electrode on the opposite side of the solid electrolyte. As the electrolyte material for forming the solid electrolyte, yttria-stabilized zirconia ((ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 , hereinafter referred to as "8YSZ") is well known. Scandia stabilized zirconia ((ZrO ₂ ) _0.9 (Sc ₂ O ₃ ) _0.1 (hereinafter referred to as "10ScSZ") using zirconia stabilizer zirconia stabilizer is also known as an electrolyte material for a solid electrolyte. 10ScSZ is characterized by mechanical properties such as 3-point bending strength and fracture toughness equal to 8YSZ, and the conductivity of 10ScSZ is about 3 times higher than that of 8YSZ.

It is known that 10ScSZ has a cubic crystal state at a high temperature region, but a phase transition to a rhombohedral state at a cubic phase occurs at around 550 ° C. When this phase transition occurs, the conductivity of 10ScSZ sharply drops. That is, 10ScSZ is a material having a large temperature dependence of electric conductivity. In addition, such a phase transition causes a volume change, and consequently, there is a drawback that fine cracks may occur in the sintered body of 10ScSZ. In order to stabilize the crystal state of 10ScSZ, it has been reported that it is effective to add, for example, an element such as Ce, In, Ga or the like to 10ScSZ (see, for example, Non-Patent Document 1). By adding such an element to 10ScSZ, the crystal state of 10ScSZ is stabilized and the temperature dependency of conductivity is reduced. In particular, Zr _{0 .89} Sc _{0 .10} Ce _{0 .01} O _{a prepared} by adding Ce to scandia stabilized zirconia has already been commercialized.

[Non-Patent Document 1] J. Am. Ceram. 95 [6] 1965-1972 (2012)

As described above, in the scandia-stabilized zirconia added with an element such as Ce, the crystal structure is stabilized, and abrupt change of the conductivity in a constant temperature range is suppressed. However, even such scandia-stabilized zirconia is difficult to impart a high output characteristic to a solid oxide fuel cell, and there is room for further improvement in the output characteristic. Especially, in recent years, it is required to construct a power generation system with higher energy efficiency, so that a solid electrolyte capable of meeting such a high demand has not been developed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and it is an object of the present invention to provide an electrolyte composition for a solid oxide fuel cell and a solid oxide fuel cell having a high conductivity in a wide temperature range and capable of imparting excellent output characteristics to the solid oxide fuel cell The purpose.

As a result of intensive research to achieve the above object, the inventor of the present invention has found that the above object can be achieved by Scandia stabilized zirconia with at least one of Nd and Sm added thereto, and have completed the present invention.

That is, the present invention relates to the following electrolyte composition for a solid oxide fuel cell and a solid oxide fuel cell.

1. Scandium oxide stabilized zirconium oxide based electrolyte composition for use in a solid oxide fuel cell,

1. A composition comprising a compound represented by the following formula (1)

The compounds and the conductivity at ^{600 ℃ 1.4 × 10 -2 (S} / cm) or more, the power density is more than 25.0 (mW / cm ²⁾ at 600 ℃,

The compound is an electrolyte composition characterized in that phase transition to a rhombohedral state does not occur on a cubic phase at a temperature range of 25 to 850 캜.

&Lt; Formula 1 >

_{(ZrO 2) 1-xa (} Sc 2 O 3) x (M 2 O 3) a

(Wherein x in the above formula (1) is 0.09? X? 0.11,

On the other hand, a satisfies 0 < a &lt; 0.025,

M is at least one element of Sm and Nd.)

2. The electrolyte composition according to claim ¹ , wherein the compound has a conductivity of at least 8.5 x 10 &lt; ^-3 &gt; (S / cm) at 550 DEG C and an output density of 10.0 (mW / cm &lt;

3. The electrolyte composition according to claim ¹ , wherein the compound has a conductivity of at least 3.0 x ^10-3 (S / cm) at 500 占 폚, and an output density of at least 4.0 mW / cm2 at 500 占 폚.

4. A scandium oxide stabilized zirconium oxide based electrolyte composition for use in a solid oxide fuel cell,

1. A composition comprising a compound represented by the following formula (1)

The compounds and the conductivity at ^{600 ℃ 1.4 × 10 -2 (S} / cm) or more, the power density is more than 25.0 (mW / cm ²⁾ at 600 ℃,

Wherein said compound does not cause phase transition to the rhombohedral state on the cubic phase in the temperature range of 25 to 850 캜.

&Lt; Formula 1 >

_{(ZrO 2) 1-xa (} Sc 2 O 3) x (M 2 O 3) a

(Wherein x in the above formula (1) is 0.09? X? 0.11,

On the other hand, a satisfies 0 < a &lt; 0.015,

M is at least one element of Sm and Nd.)

5. The electrolyte composition according to claim ¹ , wherein the compound has a conductivity of at least 8.5 x ^10-3 (S / cm) at 550 DEG C and an output density of at least 10.0 (mW / cm2) at 550 DEG C.

6. The electrolyte composition according to claim ¹ , wherein the compound has a conductivity of 3.0 x 10 &lt; ^-3 &gt; (S / cm) at 500 DEG C and an output density of 4.0 mW / cm &

7. A solid oxide fuel cell comprising a solid electrolyte composed of the electrolyte composition described above, having a fuel electrode on one side and a single cell structure on the opposite side.

The electrolyte composition for a solid oxide fuel cell of the present invention has a high conductivity in a wide temperature range and can give a high output density to a solid oxide fuel cell because the phase transition from a cubic phase to a rhombohedral state does not occur. Therefore, when the solid oxide fuel cell is constituted of such an electrolyte composition, the solid oxide fuel cell can achieve high power generation efficiency, and an excellent power generation system can be constructed.

1 is a schematic view of a measuring apparatus for evaluating power generation characteristics of an SOFC.
Fig. 2 is an Arrhenius diagram showing the relationship between the conductivity and temperature of the sintered body obtained in Examples and Comparative Examples. Fig.

Hereinafter, embodiments of the present invention will be described in detail.

The electrolyte composition of the present invention contains a scandium oxide stabilized zirconium oxide based compound represented by the following formula (hereinafter referred to as "compound A").

&Lt; Formula 1 >

_{(ZrO 2) 1-xa (} Sc 2 O 3) x (M 2 O 3) a

Here, x in the above formula (1) is 0.09? X? 0.11,

On the other hand, a satisfies 0 < a &lt; 0.025,

M is at least one element of Sm and Nd.

In addition, the compound A had an electric conductivity of 1.4 x 10 ^-2 (S / cm) or more at 600 ° C, an output density of 25.0 (mW / cm ² ) or more at 600 ° C, The upper limit is not particularly limited, but may be, for example, 3.5 x 10 ^-2 (S / cm). The upper limit of the output density at 600 캜 of Compound A is not particularly limited, but may be, for example, 50.0 (mW / cm ² ).

Here, the output density of the compound A in this specification refers to the output density measurement value of a solid oxide fuel cell comprising a solid electrolyte formed of an electrolyte composition. Details of the measuring apparatus and the measuring method will be described in the following embodiments.

Compound A has a property that phase transition to rhombohedral state does not occur on the cubic phase at a temperature range of 25 to 850 ° C. When Compound A undergoes a phase transition from the cubic phase to the rhombohedral phase at a temperature range of 25 to 850 ° C, the conductivity is greatly lowered. On the other hand, when the compound A maintains the cubic steady state in the temperature range of 25 to 850 캜, it has a high conductivity in the temperature range, and the temperature dependence of the conductivity becomes small.

Whether Compound A causes phase transition from rhombohedral phase to rhombohedral phase can be confirmed by X-ray diffraction peak in X-ray diffraction measurement. Specifically, X-ray diffraction peaks observed in the vicinity of 2θ = 28 to 32 °, 49 to 52 ° and 59 to 62 ° in the X-ray diffraction peaks obtained by X-ray diffraction measurement on the surface of the sintered body of Compound A were divided into two , It can be judged that the cuboid is normal. In addition, rhizome normal can be called triple normal.

The electrolyte composition containing the compound A as described above can be used as an electrolyte material for forming a solid electrolyte contained in a solid oxide fuel cell (SOFC). Particularly, the compound A has a high conductivity and a high output density, so that it is possible to provide a solid oxide fuel cell which can impart good output characteristics to the solid oxide fuel cell and has excellent generation efficiency.

If x is out of the range of 0.09? X? 0.11 in the above formula (1), the conductivity and the power density of the compound A do not become as high as described above, and excellent output characteristics can not be imparted to the solid oxide fuel cell. In addition, even when a is out of the range of 0 < a < 0.025, the conductivity and the power density of the compound A do not become as high values as described above, and excellent output characteristics can not be imparted to the solid oxide fuel cell. In the formula (1), it is preferable that a is in the range of 0 &lt; a &lt; 0.015, and the conductivity and the output density of the compound A show a higher value.

In the above formula (1), when M is an element other than Sm and Nd, the compound A is more likely to undergo phase transition to the rhombohedral state at 25 to 850 ° C in cubic phase, and the temperature dependence of the conductivity becomes larger. In addition, when M is an element other than Sm and Nd, it is difficult to have a desired value of electric conductivity and power density even if the phase transition of the compound A does not occur. The compound A may be at least one of Sm and Nd in the formula (1), but may be two. In this case, the compound A is a mixture of a compound in which M is Sm and a compound in which M is Nd.

Compound A is not less than a conductivity of ^{8.5 × 10 -3 (S / cm} ) at 550 ℃, it is preferable that the power density is less than 10.0 (mW / cm ²⁾ at 550 ℃. In this case, when the solid electrolyte is formed of the electrolyte composition containing the compound A, the power generation efficiency of the solid oxide fuel cell can be further increased.

In addition, the compound A is having a conductivity of ^{3.0 × 10 -3 (S / cm} ) or more at 500 ℃, it is also preferable that the power density is less than 4.0 (mW / cm ²⁾ at 500 ℃. Even in this case, high power generation efficiency can be given to the solid oxide fuel cell.

Compound A can be produced by various methods such as the coprecipitation method, the solid-phase reaction method, and the sol-gel method, which have been conventionally performed. Particularly, when Compound A is prepared by coprecipitation, Compound A is more uniformly compounded and the stability of the crystal structure is enhanced, and consequently, a higher output density can be imparted to the solid oxide fuel cell. From this viewpoint, the compound A is preferably prepared by co-precipitation.

When the compound A is prepared by coprecipitation, it can be carried out, for example, in the following sequence. First, an aqueous solution of ZrOCl ₂ is mixed with a nitrate solution of Sc ₂ O ₃ in which a required amount of M ₂ O ₃ (M is at least one of Sm and Nd) is dissolved to prepare a mixed aqueous solution. By adding ammonia water or the like as a co-precipitant to this mixed aqueous solution, a mixed precipitate containing a mixed hydrate of Zr hydrate and Sc hydrate and M ₂ O ₃ hydrate can be obtained. Subsequently, the obtained mixed precipitate is washed, filtered and solid-liquid separated, and the separated solid is calcined at a temperature of 600 to 1000 ° C. for about 5 to 12 hours. Finally, the solid obtained by calcination is pulverized to synthesize Compound A, which is a mixed powder of zirconia of scandia stabilized with M ₂ O ₃ .

The co-precipitation method is merely an example, and the medicines and procedures such as the co-precipitant to be used can be appropriately changed. For example, the starting material can be neutralized by adding a certain amount of salt solution to the basic zirconium sulfate.

On the other hand, as the solid phase reaction method, Compound A can be prepared, for example, by the following method. Scandia-stabilized zirconia (e.g., (ZrO ₂ ) _0.90 (Sc ₂ O ₃ ) _0.10 ) and Nd ₂ O ₃ are prepared as starting materials and kneaded in the presence of distilled water using a ball mill or the like. Then, the moisture is dried, and the calcination is carried out at a predetermined temperature. A binder such as an acrylic resin is added to the temporary material thus obtained, followed by wet pulverization, moisture drying, and sintering to produce Compound A.

The compound A thus prepared is mainly composed of Scandia stabilized zirconia (hereinafter referred to as "ScSZ") in which Scandia (Sc ₂ O ₃ ) is dissolved in zirconia (ZrO ₂ ). In this ScSZ, M ₂ O ₃ (Sm ₂ O ₃ or Nd ₂ O ₃ ) is present in a solid state, and the crystal phase (cubic normal) of the compound A is stabilized by the presence of M ₂ O ₃ .

The electrolyte composition may contain other solid electrolytes and additives as long as it does not impair the effects of the present invention in addition to the above-mentioned compound A. Alternatively, the electrolyte composition may be composed of only Compound A.

The electrolyte composition can be molded into a plate-like solid electrolyte by a method of pressure molding with an hydrostatic press, or a doctor blade method or calender roll method. Solid electrolytes on these plates are used as SOFC solid electrolyte plates. When the electrolyte composition is molded into the solid electrolyte plate, the molding conditions and the like are not particularly limited and can be the same as the conventional conditions.

A solid electrolyte fuel cell having a single cell structure in which a fuel electrode is formed on one side of the solid electrolyte plate and an air electrode is formed on the opposite side to form a fuel electrode on one side of the solid electrolyte and an air electrode on the opposite side, Can be obtained.

In forming the fuel electrode on one side of the solid electrolyte plate, a slurry containing a ceramic powder for forming a fuel electrode is prepared, and this slurry is coated on one side of the solid electrolyte plate by a so-called slurry coating method, Lt; / RTI &gt; As a result, a fuel electrode in the form of a thin film is formed on one surface of the solid electrolyte plate. As the ceramic powder for forming the fuel electrode, for example, a nickel-zirconia cermet material composed of 40% by weight of nickel and 60% by weight of zirconia may be exemplified. However, have. The thickness of the fuel electrode may be, for example, 50 μm, but is not limited to this thickness.

On the other hand, in forming the air electrode on the solid electrolyte plate, the air electrode is coated on one side of the solid electrolyte plate by a slurry coating method using a slurry including a ceramic powder for forming an air electrode as well as a fuel electrode, Firing is performed. As a result, a thin air electrode is formed on the surface of the solid electrolyte plate opposite to the surface on which the fuel electrode is formed. As the ceramic powder for forming the air electrode, for example, lanthanum strontium manganite (La (Sr) MnO ₃ ) and the like are exemplified, but ceramic powders conventionally used as air poles can also be used. The thickness of the air electrode may be, for example, 50 μm, but is not limited to this thickness.

Since the solid oxide fuel cell constructed as described above is provided with the solid electrolyte plate formed of the electrolyte composition of the present invention, it has high output density and excellent power generation efficiency. Therefore, by using such a solid oxide fuel cell, it is possible to construct a power generation system with high energy efficiency.

<Examples>

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the materials obtained in Examples and Comparative Examples, hafnium oxide as an unavoidable impurity is contained in an amount of 1.3 to 2.5% by weight based on the zirconium oxide.

&Lt; Example 1 >

First, basic zirconium sulfate (87.6 g in terms of zirconium oxide) was dispersed in 1000 g of water. The scandium salt solution recovered in this dispersion was adjusted to 10 mol% (11.0 g in terms of scandium oxide) in terms of zirconium oxide converted to basic zirconium sulfate, and 0.5 mol% of neodymium chloride solution (1.4 g in terms of neodymium oxide) To prepare a mixed solution. Subsequently, a 25 wt% aqueous solution of sodium hydroxide was added until the pH of the mixed solution became 13.5 to obtain a precipitate. The resulting precipitate was separated by solid-liquid separation and recovered, and the resulting solid fraction was calcined in the air at 1000 캜 for 5 hours to obtain an electrolyte composition. The electrolyte composition is _{(ZrO 2) 1-xa (} Sc 2 O 3) x (Nd 2 O 3) a compound represented by the general formula of (where x = 0.10, a = 0.005) .

Subsequently, the electrolyte composition was molded into a disc shape using a uniaxial die press at a molding pressure of 100 MPa. The sintered body thus obtained was sintered on a zirconia setter for 3 hours under the conditions of 1450 ° C in the air to obtain a sintered body.

&Lt; Example 2 >

An electrolyte composition was prepared in the same manner as in Example 1 except that the neodymium chloride solution was changed to a samarium chloride solution to obtain a sintered body. The compound constituting the electrolyte composition prepared in this Example is represented by the formula of (ZrO ₂ ) _1-xa (Sc ₂ O ₃ ) _x (Sm ₂ O ₃ ) _a (where x = 0.10, a = 0.005).

&Lt; Comparative Example 1 &

An electrolyte composition was prepared in the same manner as in Example 1 except that the neodymium chloride solution was changed to a cerium chloride solution to obtain a sintered body. The compound constituting the electrolyte composition prepared in this Comparative Example is represented by the formula (ZrO ₂ ) _{1- x a} (Sc ₂ O ₃ ) _x (CeO ₂ ) _a (where x = 0.10, a = 0.01).

&Lt; Comparative Example 2 &

A sintered body was obtained in the same manner as in Example 1, except that the electrolyte composition was composed of only Scandia stabilized zirconia (ZrO ₂ ) _0.90 (Sc ₂ O ₃ ) _0.10 (hereinafter referred to as "10ScSZ"

<Evaluation method>

With respect to the sintered bodies obtained in the above examples and comparative examples, the determination of the crystal state of the sintered body, the determination of the phase transition between the sintered cubic normal and the rhombohedral body, and the conductivity measurement of the sintered body were carried out. The SOFC power generation characteristics were evaluated when the sintered body was used as a solid electrolyte. Each evaluation method is as follows.

&Lt; Determination of crystalline state of sintered body &

Determination of the presence of either cubic or rhombohedral crystals in the sintered body was determined by X-ray diffraction (XRD) measurement spectra. X-ray diffraction measurements were carried out at room temperature in the range of 2θ = 20 ° to 80 ° with CuKα1 line using "MiniFlex Ⅱ" from the scientific department. Specifically, the X-ray diffraction peaks observed at around 2? = 28 to 32, 49 to 52 and 59 to 62 in the X-ray diffraction peaks observed in the X-ray diffraction measurement of the surface of the sintered body are divided into two , It was judged to be rhomboid normal, and in the case of not breaking, it was judged to be cubic normal.

&Lt; Determination of phase transition of sintered body &

The determination of the phase transition between the cubic steady state and the rhombohedral steady state at around 550 캜 of the sintered body was carried out by measuring the conductivity. The conductivity measurement was performed as follows. A Pt paste (PT Practical Best Co., No. 8105, made by Tokuriki Chemical Co., Ltd.) was applied to both surfaces of the sintered body, and the Pt wires were connected and then plated at 1000 캜 to prepare a Pt electrode for conductivity measurement. The sintered body used here is φ 12 mm and thickness t 3 mm. The Pt electrode has a φ of 6 mm and a sample thickness of 3 mm. The conductivity is measured by using an impedance meter (HP4194A) at a frequency range of 100 Hz to 10 MHz and plotting the relationship between conductivity and temperature by a complex impedance analysis in a temperature range of 300 ° C. to 800 ° C. (Arrhenius Plots). When the conductivity of the sintered body is measured in a temperature range of 300 ° C to 800 ° C and an Arrhenius plot showing a nearly linear change in conductivity in the entire temperature range is obtained, it is determined that there is no phase change, and a linear conductivity change When a change in the conductivity was observed, it was determined that there was a phase change.

&Lt; Measurement of conductivity &

The conductivity measurement was carried out in the same manner as the conductivity measurement performed in the determination of the phase transition of the sintered body.

<Characteristics of SOFC power generation>

The SOFC power generation characteristics were evaluated in the measuring apparatus 10 shown in Fig. The measuring device 10 has a single cell 5 housed in a quartz glass tube 6 and is configured to be able to apply an external voltage to the single cell 5. The single cell 5 is provided with Pt electrodes 2 (8 mm) on both sides of a sintered body 1 having a diameter of 25 mm and a thickness of 1 mm, 4). The Pt electrode 2 can be formed on both surfaces of the sintered body 1 by an ion coater. The SOFC power generation characteristics were evaluated by measuring the voltage and power density in the range of 450 to 600 ° C. by using the SOFC apparatus for testing 10 and plotting the relationship between the current and the voltage at each temperature and the relationship between the current and the output density. Respectively. During the measurement, 3% -H ₂ gas (nitrogen balance) was supplied to the fuel electrode 3 at a flow rate of 800 mL · min ^-1 and air was flowed to the air electrode 4 at a flow rate of 300 mL · min ^-1 .

Fig. 2 shows the relationship (Arrhenius plot) between the conductivity (longitudinal axis) of the sintered bodies in each of the examples and the comparative examples and the reciprocal of the temperature (transverse axis).

The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1, And the maximum power density at the maximum power density.

In the XRD measurement, only the cubic phase was observed in the sintered bodies of Example 2 and Comparative Example 1, and the sintered bodies of Comparative Example 2 were found to be mixed with cubic normal and rhombohedral normal. Further, as can be seen from the Arrhenius plot in FIG. 2, it was found that the ratio of (1ScSZ + 1.0 mol% Nd) of Example 1 (10ScSZ + 1.0 mol% In the sintered body, almost linear change in conductivity was observed in all the temperature range, and it can be said that the phase transition from the cubic phase to the rhombohedral state does not occur. On the other hand, in the sintered body of Comparative Example 2 (10ScSZ), a sharp decrease in conductivity was observed at around 550 占 폚. This is because the phase transition from the cubic phase to the rhombohedral state occurred at around 550 ° C.

As shown in Table 1, the electric conductivity at 600 ° C, 550 ° C and 500 ° C showed the same value in all of the sintered bodies of Examples 1 and 2 and Comparative Example 1. On the other hand, when the maximum power density at 600 캜 is compared, it can be seen that the SOFC fabricated from the sintered bodies of Examples 1 and 2 has higher maximum power density than the SOFC fabricated from the sintered body of Comparative Example 1. From this fact, it can be said that the solid electrolyte consisting of 10ScSZ stabilized with Nd or Sm can give higher power generation characteristics than solid electrolytes composed of 10ScSZ stabilized with Ce. In Comparative Example 2, 10ScSZ at 600 캜 exhibited a higher electric conductivity and a higher power density than Examples 1 and 2. However, as described above, since 10ScSZ of Comparative Example 2 undergoes phase transition from the cubic phase to the rhombohedral phase, there is a problem that fine cracks are generated in the sintered body due to the volume change due to the phase transition.

EXAMPLES / COMPARATIVE EXAMPLE Sample Phase transition
600 ℃ 550 ℃ 500 ℃ Conductivity /
S? Cm ^-1 Maximum power density /
mW cm ^-2 Conductivity /
S? Cm ^-1 Maximum power density /
mW cm ^-2 Conductivity /
S? Cm ^-1 Maximum power density /
mW cm ^-2 Example 1 10ScSZ + 1.0 mol% Nd none 2.1 x 10 ^-2 27.3 1.2 × 10 ^-2 14.4 4.2 x 10 ^-3 5.4 Example 2 10ScSZ + 1.0 mol% Sm none 2.2 x 10 ^-2 29.8 1.3 x 10 ^-2 11.0 5.0 x 10 ^-3 4.3 Comparative Example 1 10ScSZ + 1.0 mol% Ce none 2.4 × 10 ^-2 22.1 1.3 x 10 ^-2 13.2 5.3 × 10 ^-3 5.3 Comparative Example 2 10ScSZ has exist 3.3 x 10 ^-2 31.1 1.5 x 10 ^-2 13.8 0.1 x 10 ^-3 0.2

The electrolyte composition of the present invention has high conductivity in a wide temperature range and can give a high output density to a solid oxide fuel cell. Therefore, such an electrolyte composition is useful as an electrolyte material of a solid electrolyte constituting a solid oxide fuel cell. In addition, the solid oxide fuel cell produced using the electrolyte composition of the present invention has a high output density and excellent power generation efficiency, which helps construct a power generation system with excellent energy efficiency.

1: sintered body
2: Pt electrode
3: fuel pole
4: air pole
5: Single cell
6: Quartz glass tube
10: Measuring device

Claims (7)

A scandium oxide stabilized zirconium oxide based electrolyte composition for use in a solid oxide fuel cell,
1. A composition comprising a compound represented by the following formula (1)
The compounds and the conductivity at ^{600 ℃ 1.4 × 10 -2 (S} / cm) or more, the power density is more than 25.0 (mW / cm ²⁾ at 600 ℃,
Wherein said compound does not cause phase transition to the rhombohedral state on the cubic phase in the temperature range of 25 to 850 캜.

&Lt; Formula 1 >
_{(ZrO 2) 1-xa (} Sc 2 O 3) x (M 2 O 3) a
(Wherein x in the above formula (1) is 0.09? X? 0.11,
On the other hand, a satisfies 0 < a &lt; 0.025,
And M is at least one element of Sm and Nd).
The method according to claim 1,
The compounds 8.5, the conductivity at ^{550 ℃ × 10 -3 (S /} cm) or more, the output density of 10.0 at 550 ℃ (mW / cm ²⁾ electrolyte composition, characterized in that at least.
The method according to claim 1,
The compounds in the conductivity 3.0 ^{500 ℃ × 10 -3 (S /} cm) or more, the output density at 500 ℃ 4.0 (mW / cm ²⁾ electrolyte composition, characterized in that at least.
A scandium oxide stabilized zirconium oxide based electrolyte composition for use in a solid oxide fuel cell,
1. A composition comprising a compound represented by the following formula (1)
The compounds and the conductivity at ^{600 ℃ 1.4 × 10 -2 (S} / cm) or more, the power density is more than 25.0 (mW / cm ²⁾ at 600 ℃,
Wherein said compound does not cause phase transition to the rhombohedral state on the cubic phase in the temperature range of 25 to 850 캜.

&Lt; Formula 1 >
_{(ZrO 2) 1-xa (} Sc 2 O 3) x (M 2 O 3) a
(Wherein x in the above formula (1) is 0.09? X? 0.11,
On the other hand, a satisfies 0 < a &lt; 0.015,
M is at least one element of Sm and Nd.)
5. The method of claim 4,
The compounds 8.5, the conductivity at ^{550 ℃ × 10 -3 (S /} cm) or more, the output density of 10.0 at 550 ℃ (mW / cm ²⁾ electrolyte composition, characterized in that at least.
5. The method of claim 4,
The compounds in the conductivity 3.0 ^{500 ℃ × 10 -3 (S /} cm) or more, the output density at 500 ℃ 4.0 (mW / cm ²⁾ electrolyte composition, characterized in that at least.
A solid oxide fuel cell comprising a solid electrolyte composed of the electrolyte composition according to any one of claims 1 to 6 and having a fuel electrode on one surface and a single cell structure having air electrodes on the opposite surface, .

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