JP3034132B2 - Zirconia solid electrolyte - Google Patents
Zirconia solid electrolyteInfo
- Publication number
- JP3034132B2 JP3034132B2 JP4259468A JP25946892A JP3034132B2 JP 3034132 B2 JP3034132 B2 JP 3034132B2 JP 4259468 A JP4259468 A JP 4259468A JP 25946892 A JP25946892 A JP 25946892A JP 3034132 B2 JP3034132 B2 JP 3034132B2
- Authority
- JP
- Japan
- Prior art keywords
- solid electrolyte
- zirconia
- electric conductivity
- ionic radius
- zro
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Description
【０００１】[0001]
【発明の利用分野】本発明は、酸素センサや燃料電池な
どに好適に使用されるジルコニア質の固体電解質に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zirconia solid electrolyte suitably used for an oxygen sensor, a fuel cell, and the like.
【０００２】[0002]
【従来技術】従来から、固体電解質としては、ＺｒＯ2
にＹ2 Ｏ3 、ＣａＯ、ＭｇＯなどの安定化剤を適量添加
して、ＺｒＯ2 が立方晶相を主体としてなるジルコニア
質固体電解質が使用されている。 2. Description of the Related Art Conventionally, ZrO 2 has been used as a solid electrolyte.
A suitable amount of a stabilizer such as Y 2 O 3 , CaO or MgO is added to the zirconia solid electrolyte in which ZrO 2 is mainly composed of a cubic phase.
【０００３】また、上記のような立方晶のジルコニア質
固体電解質には、その過酷な使用条件においても十分に
耐えうるように、安定化剤の量を制御して磁器中に正方
晶相を析出させたり、焼結助剤としてＡｌ2 Ｏ3 やＳｉ
Ｏ2 などを添加することも提案されている。The cubic zirconia solid electrolyte described above has a controlled amount of a stabilizer to precipitate a tetragonal phase in a porcelain so that it can sufficiently withstand severe use conditions. Al 2 O 3 or Si as a sintering aid
It has also been proposed to add O 2 or the like.
【０００４】[0004]
【発明が解決しようとする問題点】しかしながら、従来
のジルコニア質固体電解質は、それ自体の電気伝導度が
低いという問題があった。固体電解質の電気伝導度が低
いと、酸素センサなどに使用した場合に応答が遅く、ま
た燃料電池セルに使用した場合には、抵抗が大きく、出
力を低下させる原因となっていた。However, the conventional zirconia-based solid electrolyte has a problem that its own electric conductivity is low. When the electric conductivity of the solid electrolyte is low, the response is slow when used for an oxygen sensor or the like, and when used for a fuel cell, the resistance is large and the output is reduced.
【０００５】よって、本発明は、電気伝導度の高いジル
コニア質固体電解質を提供することを目的とするもので
ある。Therefore, an object of the present invention is to provide a zirconia solid electrolyte having high electric conductivity.
【０００６】[0006]
【問題点を解決するための手段】本発明者は、ジルコニ
ア質固体電解質の電気伝導度について、検討を行ったと
ころ、固体電解質中に添加される金属酸化物をその平均
イオン半径が特定の範囲になるように適宜選択すること
により、電気伝導質を従来よりも高めることができるこ
とを知見したものである。The present inventors have studied the electrical conductivity of the zirconia-based solid electrolyte and found that the metal oxide added to the solid electrolyte has an average ionic radius within a specific range. It has been found that the electric conductivity can be increased as compared with the conventional one by appropriately selecting such that.
【０００７】即ち、本発明のジルコニア固体電解質は、
添加物として、Ｙｂ2 Ｏ3 、Ｓｍ2Ｏ3 、Ｓｃ2 Ｏ3 の
群から選ばれる少なくとも１種を選択し、これらの添加
物をＭＯ1.5 （Ｍ：金属元素）換算で１４〜３０モル％
添加するとともに、前記添加物の平均イオン半径が０．
７５〜０．８６Åとなるように上記添加物を添加するも
ので、且つ実質的に立方晶ジルコニアの単一相からなる
ことを特徴とするものである。That is, the zirconia solid electrolyte of the present invention comprises:
As the additive, at least one selected from the group consisting of Yb 2 O 3 , Sm 2 O 3 and Sc 2 O 3 is selected, and these additives are added in an amount of 14 to 30 mol% in terms of MO 1.5 (M: metal element).
With the addition, the average ionic radius of the additive is 0.1.
The above additive is added so as to be 75 to 0.86 °, and is substantially composed of a single phase of cubic zirconia.
【０００８】以下、本発明を詳述する。本発明のジルコ
ニア固体電解質は、ジルコニアを主体として、これにジ
ルコニアを立方晶に安定化させる作用をなす金属酸化物
が添加されている。このような金属酸化物としては、Ｙ
ｂ2 Ｏ3 、Ｓｍ2 Ｏ3 、Ｓｃ2 Ｏ3 の群から選ばれる少
なくとも１種を選択される。このような添加物は、ジル
コニアを立方晶に安定化させるために総量でＭＯ
1.5 （Ｍ：金属元素）として１４〜３０モル％、特に１
６〜２４モル％の割合で添加される。この添加量を上記
の範囲に限定したのは、１４モル％よりも少ないと、結
晶中に正方晶あるいは単斜晶の結晶が析出するとともに
電気伝導率が低下し、３０モル％よりも多い場合も電気
伝導率が低下するためである。Hereinafter, the present invention will be described in detail. The zirconia solid electrolyte of the present invention contains zirconia as a main component, to which a metal oxide that functions to stabilize zirconia to a cubic crystal is added. As such a metal oxide, Y
b 2 O 3, is selected the Sm 2 O 3, at least one selected from the group consisting of Sc 2 O 3. Such additives are used in a total amount of MO to stabilize zirconia to cubic.
1.5 (M: metal element) 14 to 30 mol%, especially 1
It is added at a rate of 6 to 24 mol%. The reason why the addition amount is limited to the above range is that, when the amount is less than 14 mol%, tetragonal or monoclinic crystals are precipitated in the crystal and the electric conductivity is reduced. This is also because the electric conductivity decreases.
【０００９】本発明によれば、上記に列記した金属酸化
物からこれらの平均イオン半径が０．７５〜０．８６
Å、特に０．７８〜０．８４Åとなるように選択するこ
とが重要である。なお、平均イオン半径は、下記数１で
表される。According to the present invention, the metal oxides listed above have an average ionic radius of 0.75 to 0.86
It is important to select {, especially 0.78 to 0.84}. The average ion radius is represented by the following equation (1).
【００１０】[0010]
【数１】 (Equation 1)
【００１１】平均イオン半径を上記の範囲に限定したの
は、上記範囲を逸脱するといずれも電気伝導度が低下す
るためである。ここで、イオン半径は、いずれも６配位
の数値を用いたものであり、Ｙｂは０．８６Å、Ｓｍは
０．９６Å、Ｓｃは０．７３Åとして平均イオン半径を
算出するものとする。The reason for limiting the average ionic radius to the above range is that any deviation from the above range results in a decrease in electric conductivity. Here, the ionic radius uses a numerical value of six coordinations, and the average ionic radius is calculated assuming that Yb is 0.86 °, Sm is 0.96 °, and Sc is 0.73 °.
【００１２】また、本発明によれば、固体電解質を構成
するジルコニア結晶は、実質的に立方晶ＺｒＯ2 のみか
ら構成され、単斜晶ジルコニアおよび正方晶ジルコニア
を含まないのであり、Ｘ線回折測定において立方晶ジル
コニアの（１１１）面のピーク強度に対して、正方晶ジ
ルコニアの（１１１）面のピーク強度および単斜晶ジル
コニアの（−１１１）面のピーク強度がそれぞれ５％以
下である。また、立方晶ジルコニアは平均粒径が０．５
〜５μｍの大きさで存在する。Further, according to the present invention, the zirconia crystal constituting the solid electrolyte is substantially composed of only cubic ZrO 2 and does not contain monoclinic zirconia and tetragonal zirconia. In the above, the peak intensity of the (111) plane of tetragonal zirconia and the peak intensity of the (−111) plane of monoclinic zirconia are each 5% or less of the peak intensity of the (111) plane of cubic zirconia. Further, cubic zirconia has an average particle size of 0.5.
It exists in a size of 5 μm.
【００１３】次に、本発明のジルコニア質固体電解質を
作製する方法について説明すると、まず、原料として平
均粒径が０．５〜１．０μｍのジルコニア粉末と、前述
した各種の金属酸化物粉末を準備して、前述した平均イ
オン半径が所定の範囲となるように金属酸化物の組合せ
で選択し、ＭＯ1.5 換算で１４〜３０モル％となる量で
添加して十分に混合後、所望の成形手段、例えば、金型
プレス，冷間静水圧プレス，押出し成形、ドクターブレ
ード法等により任意の形状に成形後、焼成する。焼成
は、１５００〜１６００℃の大気などの酸化性雰囲気に
て行われる。Next, a method for producing the zirconia-based solid electrolyte of the present invention will be described. First, zirconia powder having an average particle size of 0.5 to 1.0 μm and various metal oxide powders described above are used as raw materials. Prepare and select a combination of metal oxides so that the above-mentioned average ionic radius is within a predetermined range, add in an amount of 14 to 30 mol% in terms of MO 1.5 , mix well, and form a desired mold. After forming into an arbitrary shape by means such as a mold press, a cold isostatic press, an extrusion molding, a doctor blade method, and the like, firing is performed. The firing is performed in an oxidizing atmosphere such as an air at 1500 to 1600 ° C.
【００１４】また、固体電解質は、上記以外にＺｒＯ2
と添加物からなるターゲットより、これらの蒸気を発生
させて、所望の基体表面に蒸着させるか、またはＣＶＤ
法によりＺｒ含有ガスと添加物を構成する金属元素含有
ガスを所定の割合で混合して酸素含有雰囲気中で所定の
温度に加熱された基体表面に気相合成により析出させて
得ることもできる。The solid electrolyte is ZrO 2 other than the above.
These vapors are generated from a target composed of a metal and an additive, and are vapor-deposited on a desired substrate surface or CVD.
It can also be obtained by mixing a Zr-containing gas and a metal element-containing gas constituting an additive at a predetermined ratio by a method and depositing the mixture on a substrate surface heated to a predetermined temperature in an oxygen-containing atmosphere by vapor phase synthesis.
【００１５】[0015]
【作用】本発明によれば、ＺｒＯ2 に添加される金属酸
化物の平均イオン半径と１０００℃における固体電解質
の電気伝導度との関係を図１に示した。図１から明らか
なように、平均イオン半径と電気伝導度との間には相関
な認められ、電気伝導度は平均イオン半径が約０．８１
Åにてピークを有し、イオン半径がこれより小さいまた
は大きいと急激に電気伝導度が低下する傾向にあること
がわかる。According to the present invention, the relationship between the average ionic radius of the metal oxide added to ZrO 2 and the electric conductivity of the solid electrolyte at 1000 ° C. is shown in FIG. As is clear from FIG. 1, there is a correlation between the average ionic radius and the electric conductivity.
It can be seen that there is a peak at Å, and that if the ionic radius is smaller or larger than this, the electrical conductivity tends to sharply decrease.
【００１６】本発明によれば、平均イオン半径を０．７
５〜０．８６Åに制御することにより１０００℃におけ
る電気伝導度５×１０-3Ｓ／ｃｍ以上が達成されるもの
である。According to the present invention, the average ion radius is 0.7
By controlling the temperature to 5 to 0.86 °, an electric conductivity of 5 × 10 −3 S / cm or more at 1000 ° C. is achieved.
【００１７】[0017]
【実施例】平均粒径が１μｍのＺｒＯ2 原料粉末と、平
均粒径が０．５〜２μｍのＹｂ2Ｏ3 、Ｙ2 Ｏ3 、Ｓｃ
2 Ｏ3 、Ｓｍ2 Ｏ3 、Ｅｒ2 Ｏ3 の各粉末を準備した。
これらの添加物を表１および表２に示す割合にて混合し
てＺｒＯ2 粉末とボールミルにより十分に混合した。こ
れをプレス成形し、１６００℃の大気中で１０時間焼成
した。得られた磁器は相対密度９５％以上の高緻密体で
あった。EXAMPLE ZrO 2 raw material powder having an average particle size of 1 μm and Yb 2 O 3 , Y 2 O 3 , Sc having an average particle size of 0.5 to 2 μm
Powders of 2 O 3 , Sm 2 O 3 , and Er 2 O 3 were prepared.
These additives were mixed at the ratios shown in Tables 1 and 2 and thoroughly mixed with ZrO 2 powder by a ball mill. This was press-formed and fired in the air at 1600 ° C. for 10 hours. The obtained porcelain was a highly dense body having a relative density of 95% or more.
【００１８】[0018]
【実施例】得られた磁器をＸ線回折測定を行い、結晶相
の同定と、電気伝導度の測定を行った。その結果、表
１、表２の試料中、試料Ｎo.１、２、３、７、８につい
てはいずれも立方晶ＺｒＯ2 の単一相からなりその他の
結晶相はなかったのに対して、試料Ｎo.４、５、６は、
立方晶ＺｒＯ2 以外に正方晶ＺｒＯ2 や単斜晶ＺｒＯ2
などの存在が認められた。なお、種々の金属酸化物との
組み合わせに基づき前述した数１により算出し、平均イ
オン半径と電気伝導度（ｌｏｇσ）との関係を図１に示
した。EXAMPLES The obtained porcelain was subjected to X-ray diffraction measurement to identify a crystal phase and measure electric conductivity. As a result, in the samples of Tables 1 and 2, Samples Nos. 1, 2, 3, 7, and 8 all consisted of a single phase of cubic ZrO 2 and had no other crystal phases. Sample Nos. 4, 5, and 6
In addition to cubic ZrO 2 , tetragonal ZrO 2 and monoclinic ZrO 2
The existence of such was recognized. The relationship between the average ionic radius and the electric conductivity (log σ) was calculated based on the above-described formula 1 based on the combination with various metal oxides, and shown in FIG.
【００１９】[0019]
【表１】 [Table 1]
【００２０】[0020]
【表２】 [Table 2]
【００２１】表１、表２および図１から明らかなよう
に、添加物の添加量それぞれにおいて、平均イオン半径
が約０．８１Åにて極大値を示した。なお、添加量が３
０モル％を越えると、急激に電気伝導率が低下し、１４
モル％より小さい場合にも同様に電気伝導率が低下し
た。As is clear from Tables 1 and 2, and FIG. 1, each of the additive amounts showed a maximum value when the average ionic radius was about 0.81 °. When the addition amount is 3
If it exceeds 0 mol%, the electrical conductivity will decrease sharply,
When the amount is smaller than mol%, the electric conductivity similarly decreased.
【００２２】本発明により添加量を１４〜３０モル％、
平均イオン半径を０．７５〜０．８６Åに制御すること
により１０００℃における電気伝導率が５×１０-3Ｓ／
ｃｍ以上が達成された。According to the present invention, the addition amount is 14 to 30 mol%,
By controlling the average ionic radius to 0.75 to 0.86 °, the electric conductivity at 1000 ° C. is 5 × 10 −3 S /
cm or more has been achieved.
【００２３】[0023]
【発明の効果】以上詳述した通り、本発明のＺｒＯ2 固
体電解質は、特定の金属酸化物より平均イオン半径が特
定の範囲となるように選択することにより、電気伝導率
を高めることができる。これにより、酸素センサに適用
した場合には、応答性を高めることができ、燃料電池に
適用した場合には、電解質の抵抗を下げることができる
ために出力を高めることができる。As described in detail above, the ZrO 2 solid electrolyte of the present invention can increase the electric conductivity by selecting the specific metal oxide so that the average ionic radius is within a specific range. . Thereby, when applied to an oxygen sensor, responsiveness can be improved, and when applied to a fuel cell, the output can be increased because the resistance of the electrolyte can be reduced.
【図１】平均イオン半径と電気伝導率（ｌｏｇσ）との
関係を示した図である。FIG. 1 is a diagram showing a relationship between an average ionic radius and electric conductivity (log σ).
Claims (1)
ｍ2 Ｏ3 、Ｓｃ2 Ｏ3の群から選ばれる少なくとも１種
をＭＯ1.5 （Ｍ：金属元素）換算で１４〜３０モル％添
加するとともに、前記添加物の平均イオン半径が０．７
５〜０．８６Åであり、且つ実質的に立方晶ジルコニア
の単一相からなることを特徴とするジルコニア固体電解
質。1. ZrO 2 as a main component, Yb 2 O 3 , S
At least one selected from the group consisting of m 2 O 3 and Sc 2 O 3 is added in an amount of 14 to 30 mol% in terms of MO 1.5 (M: metal element), and the average ionic radius of the additive is 0.7
A zirconia solid electrolyte having a thickness of 5 to 0.86 ° and substantially consisting of a single phase of cubic zirconia.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4259468A JP3034132B2 (en) | 1992-09-29 | 1992-09-29 | Zirconia solid electrolyte |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4259468A JP3034132B2 (en) | 1992-09-29 | 1992-09-29 | Zirconia solid electrolyte |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06116026A JPH06116026A (en) | 1994-04-26 |
| JP3034132B2 true JP3034132B2 (en) | 2000-04-17 |
Family
ID=17334499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4259468A Expired - Fee Related JP3034132B2 (en) | 1992-09-29 | 1992-09-29 | Zirconia solid electrolyte |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3034132B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU9096198A (en) * | 1997-09-24 | 1999-04-12 | Nippon Shokubai Co., Ltd. | Zirconia sinter for solid electrolite and process for producing the same |
| JP2000340240A (en) * | 1999-05-31 | 2000-12-08 | Toho Gas Co Ltd | High ionic conductive solid electrolyte material and solid electrolyte fuel cell using the same |
| JP2005259556A (en) * | 2004-03-12 | 2005-09-22 | Nissan Motor Co Ltd | Solid electrolyte and its manufacturing method |
| JP2007008775A (en) * | 2005-06-30 | 2007-01-18 | National Institute Of Advanced Industrial & Technology | Porous zirconia thick film and method of manufacturing the same |
| CN100347130C (en) * | 2006-03-03 | 2007-11-07 | 中国科学院上海硅酸盐研究所 | Ytterbium oxide and yttrium oxide co-stabilized zirconia ceramic material and its prepn process |
| JP5311913B2 (en) * | 2008-07-28 | 2013-10-09 | 東邦瓦斯株式会社 | Method for producing high ion conductive solid electrolyte material |
| JP5194051B2 (en) * | 2010-05-14 | 2013-05-08 | 日本特殊陶業株式会社 | Gas sensor element and gas sensor |
| KR101867161B1 (en) * | 2016-06-28 | 2018-06-14 | 주식회사케이세라셀 | Scandia stabilized zirconia electrolyte for solid oxide fuel cells with improved reducing atmosphere stability |
-
1992
- 1992-09-29 JP JP4259468A patent/JP3034132B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06116026A (en) | 1994-04-26 |
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