JPH0782023A - Production of electrically conductive ceramic and production of solid electrolyte-type fuel cell - Google Patents
Production of electrically conductive ceramic and production of solid electrolyte-type fuel cellInfo
- Publication number
- JPH0782023A JPH0782023A JP5227462A JP22746293A JPH0782023A JP H0782023 A JPH0782023 A JP H0782023A JP 5227462 A JP5227462 A JP 5227462A JP 22746293 A JP22746293 A JP 22746293A JP H0782023 A JPH0782023 A JP H0782023A
- Authority
- JP
- Japan
- Prior art keywords
- solid electrolyte
- fuel cell
- solid solution
- conductive ceramic
- oxide
- 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.)
- Granted
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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＬａＭｎＯ3 系ペロブ
スカイト型複合酸化物からなる導電性セラミックスの製
造方法、および固体電解質型燃料電池セルの製造方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a conductive ceramic comprising LaMnO 3 type perovskite type complex oxide and a method for producing a solid oxide fuel cell.
【０００２】[0002]
【従来の技術】従来より、固体電解質型燃料電池セルと
しては、円筒型と平板型の２種類の燃料電池セルについ
て研究開発が行われている。平板型燃料電池セルは、発
電の単位体積当り出力密度が高いという特長を有する
が、実用化に関してはガスシ−ル不完全性やセル内の温
度分布の不均一性などの問題がある。それに対して、円
筒型燃料電池セルでは、出力密度は低いものの、セルの
機械的強度が高く、またセル内の温度の均一性が保てる
という特長がある。両形状の固体電解質燃料電池セルと
も、それぞれの特長を生かして積極的に研究開発が進め
られている。2. Description of the Related Art Conventionally, as solid electrolyte fuel cells, two types of fuel cells, cylindrical and flat, have been researched and developed. The flat plate type fuel cell has a feature that the power density per unit volume of power generation is high, but when it is put into practical use, there are problems such as incomplete gas seal and uneven temperature distribution in the cell. On the other hand, the cylindrical fuel cell has features that, although the power density is low, the mechanical strength of the cell is high and the temperature uniformity in the cell can be maintained. Both types of solid electrolyte fuel cells are being actively researched and developed by taking advantage of their respective characteristics.
【０００３】円筒型燃料電池の単セルは、図１に示すよ
うに開気孔率４０％程度のＣａＯ安定化ＺｒＯ2 を支持
管１とし、その上にスラリ−ディップ法により多孔性の
空気極としてＬａＭｎＯ3 系材料２を塗布し、その表面
に気相合成法（ＥＶＤ）や、あるいは溶射法により固体
電解質３であるＹ2 Ｏ3 安定化ＺｒＯ2 膜を被覆し、さ
らにこの表面に多孔性のＮｉ−ジルコニア（Ｙ2 Ｏ3 含
有）の燃料極４を設けられている。燃料電池のモジュ−
ルにおいては、各単セルはＬａＣｒＯ3 系のインタ−コ
ネクタ５を介して接続される。発電は、支持管内部に空
気（酸素）を、外部に燃料（水素）を流し、１０００〜
１０５０℃の温度で行われる。As shown in FIG. 1, a single cell of a cylindrical fuel cell uses CaO-stabilized ZrO 2 having an open porosity of about 40% as a support tube 1 and a porous air electrode formed thereon by a slurry dip method. LaMnO 3 based material 2 is applied, and the surface thereof is coated with a Y 2 O 3 stabilized ZrO 2 film which is a solid electrolyte 3 by a vapor phase synthesis method (EVD) or a thermal spraying method. A fuel electrode 4 of Ni-zirconia (containing Y 2 O 3 ) is provided. Fuel cell module
In this case, each unit cell is connected via an LaCrO 3 system interconnector 5. Power generation is performed by flowing air (oxygen) inside the support tube and fuel (hydrogen) outside,
It is carried out at a temperature of 1050 ° C.
【０００４】近年、このセル作製の工程においてプロセ
スを単純化するため、空気極材料であるＬａＭｎＯ3 系
材料を直接多孔性の支持管として使用する試みがなされ
ている。空気極としての機能を合せ持つ支持管材料とし
ては、Ｌａを２０％Ｃａで、または１５％Ｓｒで置換し
たＬａＭｎＯ3 固溶体材料が用いられている。In recent years, in order to simplify the process in the step of producing the cell, it has been attempted to directly use the LaMnO 3 material, which is an air electrode material, as a porous support tube. A LaMnO 3 solid solution material in which La is replaced by 20% Ca or 15% Sr is used as a supporting tube material that also has a function as an air electrode.
【０００５】また、平板型燃料電池の単セルは、円筒型
と同じ材料系を用いて、図２に示したように固体電解質
６の一方に多孔性の空気極材料７を、他方に多孔性の燃
料極８が設けられている。単セル間の接続には、セパレ
−タ９と呼ばれる緻密質のＭｇＯやＣａＯを添加した緻
密質のＬａＣｒＯ3 固溶体材料が用いられる。発電はセ
ルの空気極側に空気（酸素）、燃料極側に燃料（水素）
を供給して１０００〜１０５０℃の温度で行われる。Further, the unit cell of the flat plate type fuel cell uses the same material system as that of the cylindrical type, and as shown in FIG. 2, one of the solid electrolytes 6 has a porous air electrode material 7 and the other has a porous air electrode material 7. Fuel electrode 8 is provided. For the connection between the single cells, a dense LaCrO 3 solid solution material called a separator 9 to which dense MgO or CaO is added is used. Power generation is air (oxygen) on the air electrode side of the cell and fuel (hydrogen) on the fuel electrode side.
Is carried out at a temperature of 1000 to 1050 ° C.
【０００６】[0006]
【発明が解決しようとする問題点】しかしながら、従来
の空気極材料はセル作製時や発電中に固体電解質とに反
応し、その両者の界面に電気的に高抵抗の物質を生成し
発電出力が時間とともに低下したり、あるいは空気極が
剥離するという問題があった。このような空気極を構成
する導電性セラミックスと固体電解質との反応による劣
化は、燃料電池の長期発電能力を維持するには致命的な
欠点となっている。However, the conventional air electrode material reacts with the solid electrolyte at the time of cell production or during power generation to generate a substance of high resistance electrically at the interface between the both, and the power generation output is There is a problem that it decreases with time or the air electrode peels off. The deterioration due to the reaction between the conductive ceramics forming the air electrode and the solid electrolyte is a fatal drawback for maintaining the long-term power generation capacity of the fuel cell.
【０００７】よって、本発明の目的は、固体電解質との
反応性を抑制した導電性セラミックスの製造方法、およ
び発電出力の安定した長寿命の固体電解質型燃料電池セ
ル製造する方法を提供するものである。Therefore, an object of the present invention is to provide a method for producing a conductive ceramic which suppresses the reactivity with a solid electrolyte, and a method for producing a solid electrolyte fuel cell having a stable power generation output and a long life. is there.
【０００８】[0008]
【課題を解決するための手段】上述の目的に対して、本
発明者は、空気極を構成するＬａＭｎＯ3 系ペロブスカ
イト型複合酸化物の製造方法について検討を重ねた結
果、まず、セラミックスを構成する金属の酸化物の混合
物を熱処理して一旦固溶体粉末を作製するとともに、そ
の粉末の粒径を比較的粗大粒子とし、これを原料として
成形、焼成すると、その焼結体の表面に固体電解質を形
成しても長期にわたり、両者の反応性が抑制されること
を見出し、本発明に至った。To solve the above problems, the present inventor has repeatedly studied a method for producing a LaMnO 3 type perovskite type complex oxide forming an air electrode. As a result, first, a ceramic is formed. When a mixture of metal oxides is heat-treated to prepare a solid solution powder, and the particle size of the powder is made to be relatively coarse particles, and this is used as a raw material for molding and firing, a solid electrolyte is formed on the surface of the sintered body. However, the inventors have found that the reactivity of both is suppressed over a long period of time, and have reached the present invention.
【０００９】即ち、本発明は、少なくともＬａ、Ｍｎ、
アルカル土類元素および／または周期律表第３ａ族元素
を含むペロブスカイト型複合酸化物からなる導電性セラ
ミックスを製造する方法であって、前記金属の酸化物、
あるいは熱処理により酸化物を形成することのできる化
合物粉末を所定の割合で混合した後、該混合物を１４０
０℃以上で熱処理して平均粒径が４μｍ以上の固溶体粉
末を得、該固溶体粉末を所定の形状に成形した後、１１
００〜１６５０℃で焼成することを特徴とするものであ
る。That is, according to the present invention, at least La, Mn,
A method for producing a conductive ceramic comprising a perovskite-type complex oxide containing an alcal earth element and / or an element of Group 3a of the periodic table, the oxide of the metal comprising:
Alternatively, a compound powder capable of forming an oxide by heat treatment is mixed at a predetermined ratio, and then the mixture is mixed with 140
After heat treatment at 0 ° C. or higher, a solid solution powder having an average particle size of 4 μm or more is obtained, and the solid solution powder is molded into a predetermined shape.
It is characterized by firing at 00 to 1650 ° C.
【００１０】さらに、本発明の固体電解質型燃料電池セ
ルの製造方法は、上記発明に基づくもので、少なくとも
Ｌａ、Ｍｎ、アルカル土類元素および周期律表第３ａ族
元素の各金属酸化物、あるいは熱処理により酸化物を形
成することのできる化合物粉末を所定の割合で混合した
後、該混合物を１４００℃以上で熱処理して平均粒径が
４μｍ以上の固溶体粉末を得、該固溶体粉末を所定の形
状に成形した後、１１００〜１６５０℃で焼成してペロ
ブスカイト型複合酸化物からなる導電性セラミックスを
製造する工程と、前記導電性セラミックスの表面に固体
電解質膜を形成する工程と、該固体電解質膜の表面に燃
料極を形成する工程とを具備することを特徴とするもの
である。Further, the method for producing a solid oxide fuel cell of the present invention is based on the above-mentioned invention and comprises at least each metal oxide of La, Mn, an alcal earth element and an element of Group 3a of the periodic table, or A compound powder capable of forming an oxide by heat treatment is mixed at a predetermined ratio, and then the mixture is heat-treated at 1400 ° C. or higher to obtain a solid solution powder having an average particle size of 4 μm or more, and the solid solution powder has a predetermined shape. And then firing at 1100 to 1650 ° C. to produce a conductive ceramic composed of a perovskite complex oxide, a step of forming a solid electrolyte membrane on the surface of the conductive ceramic, and a step of forming the solid electrolyte membrane. And a step of forming a fuel electrode on the surface.
【００１１】以下、本発明を詳述する。本発明の導電性
セラミックスの製造方法は、少なくともＬａおよびＭｎ
を含むとともに、Ｃａ、Ｂａ、Ｓｒなどのアルカリ土類
元素やＹ、Ｙｂ、Ｅｒなどの周期律表第３ａ族元素を含
む複合酸化物の製造に適用されるものである。この複合
酸化物は、ペロブスカイト型結晶を主体とするもので、
その一般式は、下記化１で表される。The present invention will be described in detail below. The method for producing a conductive ceramic according to the present invention is at least La and Mn.
And is applied to the production of a composite oxide containing an alkaline earth element such as Ca, Ba, and Sr and an element of Group 3a of the periodic table such as Y, Yb, and Er. This composite oxide is mainly composed of perovskite type crystals,
The general formula is represented by the following chemical formula 1.
【００１２】[0012]
【化１】 [Chemical 1]
【００１３】なお、式中、Ａは周期律表第３ａ族元素、
Ｂはアルカリ土類元素、Ｃは、Ｃｏ、Ｎｉ、Ｚｒ、Ｃ
ｅ、Ｆｅ、Ｃｒの群から選ばれた少なくも１種からなる
ものであって、化１中のｘ、ｙ、ｚ、ｗは ０．２０≦ｘ＋ｙ≦０．７０ ０≦ｚ≦０．３０ ０．８８≦ｗ≦１．０５ を満足するものである。In the formula, A is an element of Group 3a of the periodic table,
B is an alkaline earth element, C is Co, Ni, Zr, C
and at least one selected from the group consisting of e, Fe, and Cr, wherein x, y, z, and w in Chemical formula 1 are 0.20 ≦ x + y ≦ 0.70 0 ≦ z ≦ 0.30 It satisfies 0.88 ≦ w ≦ 1.05.
【００１４】本発明の方法によれば、まず、上記一般式
で表される複合酸化物を構成する各金属の酸化物あるい
は熱処理によって酸化物を形成することのできる炭酸
塩、硝酸塩、酢酸塩などの化合物を準備し、これらを上
記式を満足するように秤量混合する。According to the method of the present invention, first, an oxide of each metal forming the complex oxide represented by the above general formula or a carbonate, a nitrate, an acetate or the like capable of forming an oxide by heat treatment. Are prepared, and these are weighed and mixed so as to satisfy the above formula.
【００１５】次に、その混合物を大気などの酸化性雰囲
気下で、１４００℃以上、特に１５００〜１６５０℃の
温度で２〜１５時間程度熱処理する。この熱処理により
酸化物粉末混合物を固溶体化する。この時の熱処理温度
を上記の範囲に限定したのは、熱処理温度が１４００℃
より低いと固体電解質との反応性が大きく、また粉末の
活性が大きく焼結収縮も大きくなるためである。Next, the mixture is heat-treated at a temperature of 1400 ° C. or higher, particularly 1500-1650 ° C. for about 2-15 hours in an oxidizing atmosphere such as air. By this heat treatment, the oxide powder mixture is made into a solid solution. The heat treatment temperature at this time was limited to the above range because the heat treatment temperature was 1400 ° C.
This is because if it is lower, the reactivity with the solid electrolyte is large, the activity of the powder is large, and the sintering shrinkage is large.
【００１６】さらに、本発明によれば、上記のようにし
て得られた固溶体粉末を例えば、粉砕などの処理により
平均粒径が４μｍ以上、特に５〜１０μｍの固溶体粉末
に調整することが重要である。この平均粒径を４μｍ以
上に限定したのは、４μｍより細かいと上述と同様に固
体電解質との反応性が大きく、また収縮も大きくなるた
めである。Further, according to the present invention, it is important to adjust the solid solution powder obtained as described above to a solid solution powder having an average particle size of 4 μm or more, particularly 5 to 10 μm, by a treatment such as pulverization. is there. The reason why the average particle size is limited to 4 μm or more is that if the average particle size is smaller than 4 μm, the reactivity with the solid electrolyte is large and the shrinkage is large as in the above case.
【００１７】次に、上記のようにして得られた固溶体粉
末を所望の成形手段、例えば、金型プレス，冷間静水圧
プレス，押出し成形等により任意の形状に成形し、焼成
する。焼成は、大気などの酸化性雰囲気中で１１００〜
１６５０℃で２〜１５時間程度行うことにより、１００
０℃における導電率が５０ｓ／ｃｍ以上の導電性セラミ
ックスを得ることができる。Next, the solid solution powder obtained as described above is molded into a desired shape by a desired molding means such as a die press, a cold isostatic press, an extrusion molding and the like, and is fired. Baking is 1100 to 100 in an oxidizing atmosphere such as air.
By performing at 1650 ° C for 2 to 15 hours, 100
It is possible to obtain a conductive ceramic having an electric conductivity of 50 s / cm or more at 0 ° C.
【００１８】次に、上記導電性セラミックスを空気極と
した固体電解質型燃料電池セルの製造方法について、特
に図１に示したような円筒型燃料電池セルの製造方法に
ついて具体的に説明する。円筒状燃料電池セルにおいて
は、空気極は、図１に示したように所定の多孔質支持管
の表面に形成されるか、あるいは支持管を別途設けるこ
となく、空気極自体に支持管としての機能を付加させる
場合がある。Next, a method for manufacturing a solid oxide fuel cell using the conductive ceramic as an air electrode, particularly a method for manufacturing a cylindrical fuel cell as shown in FIG. 1, will be specifically described. In the cylindrical fuel cell, the air electrode is formed on the surface of a predetermined porous support tube as shown in FIG. 1, or the air electrode itself is provided as a support tube without separately providing a support tube. Functions may be added.
【００１９】所定の支持管表面に空気極を形成する場合
には、まず、前述したようにして平均粒径が４μｍ以上
の固溶体粉末を作製し、この固溶体粉末を所定の溶媒中
に分散してスラリーを調製する。その後、そのスラリー
をＣａＯ安定化ＺｒＯ2 からなる支持管表面に浸漬塗布
−乾燥することによって所定の厚みの空気極成形体を形
成し、１４００〜１６５０℃の温度で２〜１５時間焼成
して厚み０．０５〜３μｍの空気極を形成することがで
きる。When forming an air electrode on the surface of a predetermined support tube, first, a solid solution powder having an average particle size of 4 μm or more is prepared as described above, and this solid solution powder is dispersed in a predetermined solvent. Prepare a slurry. Then, the slurry is applied onto the surface of the support tube made of CaO-stabilized ZrO 2 by dip coating and drying to form an air electrode formed body having a predetermined thickness, and the air electrode formed body is fired at a temperature of 1400 to 1650 ° C. for 2 to 15 hours to obtain a thickness. An air electrode of 0.05 to 3 μm can be formed.
【００２０】また、空気極を支持管としても機能させる
場合には、上記と同様にして得られた平均粒径４μｍ以
上の固溶体粉末を用いて、これを金型プレス，冷間静水
圧プレス，押出し成形等により円筒状に成形する。そし
て、１４００〜１６５０℃の温度で２〜１０時間焼成し
て肉厚が１〜３ｍｍの支持管兼空気極を形成することが
できる。When the air electrode also functions as a support tube, solid solution powder having an average particle size of 4 μm or more obtained in the same manner as above is used, and this is applied to a die press, a cold isostatic press, It is formed into a cylindrical shape by extrusion molding or the like. Then, it can be fired at a temperature of 1400 to 1650 ° C. for 2 to 10 hours to form a support tube / air electrode having a wall thickness of 1 to 3 mm.
【００２１】上記いずれの場合においても空気極は、開
気孔率が２０〜４０％の多孔質であることが必要であ
り、これは焼成温度や時間により任意に制御することが
できる。In any of the above cases, the air electrode needs to be porous with an open porosity of 20 to 40%, which can be arbitrarily controlled by the firing temperature and time.
【００２２】そして、上記のようにして得られた空気極
の表面に固体電解質を形成する。固体電解質は、例えば
Ｙ2 Ｏ3 を３〜２０モル％含有するＺｒＯ2 により構成
され、立方晶ＺｒＯ2 を主体としてなるものである。こ
のような固体電解質は、例えば、気相合成法（ＥＶＤ）
や溶射法などの周知の方法により１０〜３００ｍｍの厚
みに形成される。その後、この固体電解質の表面には、
スラリーディップ法あるいは溶射法などの方法によって
多孔性のＮｉ−ジルコニア（Ｙ2 Ｏ3 含有）などからな
る燃料極を５０〜１００μｍの厚みに被着形成する。Then, a solid electrolyte is formed on the surface of the air electrode obtained as described above. The solid electrolyte is composed of, for example, ZrO 2 containing 3 to 20 mol% of Y 2 O 3, and is mainly composed of cubic ZrO 2 . Such a solid electrolyte is obtained by, for example, a vapor phase synthesis method (EVD).
It is formed to a thickness of 10 to 300 mm by a well-known method such as a thermal spraying method. Then, on the surface of this solid electrolyte,
A fuel electrode made of porous Ni-zirconia (containing Y 2 O 3 ) or the like is deposited to a thickness of 50 to 100 μm by a method such as a slurry dipping method or a thermal spraying method.
【００２３】さらに、セル間を接続するために、Ｃａ、
Ｓｒ、Ｍｇなどを含有するＬａＣｒＯ3 などからなるセ
パレータをＥＶＤ法あるいは溶射法などの方法により形
成される。Further, in order to connect the cells, Ca,
A separator made of LaCrO 3 or the like containing Sr, Mg or the like is formed by a method such as an EVD method or a thermal spraying method.
【００２４】また、平板型燃料電池の場合には、前記固
溶体粉末を含むスラリーを塗布し平板状電解質表面に成
形した後、１１００〜１４００℃の温度で２〜１０時間
焼成すればよく、さらに燃料極を形成し、前記セパレー
タと同様な材質からなるインターコネクタを形成するこ
とによりセルを作製することができる。In the case of a flat plate fuel cell, a slurry containing the solid solution powder may be applied and molded on the surface of a flat plate electrolyte, followed by firing at a temperature of 1100 to 1400 ° C. for 2 to 10 hours. A cell can be produced by forming a pole and forming an interconnector made of the same material as the separator.
【００２５】本発明における導電性セラミックスは、具
体的には前記化１で示された組成からなり、空気極能を
有するために十分な導電性を有するためにはｘ、ｙ、
ｚ、ｗを前述したような範囲に制御することが望ましい
が、空気極は、固体電解質や燃料極形成時、または発電
時に高温に晒されるために多孔質の空気極自体が焼結し
て収縮し、燃料電池セルの製造時の安定性や使用時の長
期信頼性を阻害する場合がある。このような空気極の焼
成収縮を抑制するためには、前記ｘ、ｙ、ｚ、ｗは、
０．０５≦ｘ≦０．２０、０．２０≦ｙ≦０．３０、
０．９５≦ｗ≦１．００、０≦ｚ≦０．２０を満足する
ような組成に調製されることが望ましい。The electroconductive ceramics of the present invention is specifically composed of the composition shown in the above chemical formula 1, and x, y, and
Although it is desirable to control z and w in the ranges described above, the air electrode is exposed to high temperatures during formation of the solid electrolyte or fuel electrode or during power generation, and the porous air electrode itself sinters and shrinks. However, this may impair the stability during manufacture of the fuel cell and the long-term reliability during use. In order to suppress such firing shrinkage of the air electrode, x, y, z and w are
0.05 ≦ x ≦ 0.20, 0.20 ≦ y ≦ 0.30,
It is desirable to prepare the composition so as to satisfy 0.95 ≦ w ≦ 1.00 and 0 ≦ z ≦ 0.20.
【００２６】さらに、上記導電性セラミックスは、化１
において、Ｌａの一部をＴｉ、Ｚｎ、Ｃｅ、Ｓｎ、Ｃｕ
の群から選ばれる１種以上により３０ａｔｍ％以下の割
合で置換してもよい。Further, the conductive ceramics are
In, part of La is Ti, Zn, Ce, Sn, Cu
One or more selected from the group may be substituted at a rate of 30 atm% or less.
【００２７】[0027]
【作用】通常、ＬａＭｎＯ3 で表される複合酸化物は、
固体電解質（安定化ジルコニア）との化学反応によって
両者の界面に電気伝導度の小さなＬａ2 Ｚｒ2 Ｏ7 が生
成しセルの性能を劣化させたり、固体電解質から空気極
が剥離するといった弊害が生じる。このような異種物質
の粉末同志の接触による化学反応を考えた場合、反応率
をαとすると下記数１Function Normally, the complex oxide represented by LaMnO 3 is
The chemical reaction with the solid electrolyte (stabilized zirconia) produces La 2 Zr 2 O 7 with small electric conductivity at the interface between the two, resulting in the deterioration of the cell performance and the detriment of the air electrode from the solid electrolyte. . Considering the chemical reaction caused by the contact of powders of different substances, the reaction rate is α
【００２８】[0028]
【数１】 [Equation 1]
【００２９】の式が成り立つ。燃料電池セルにおける固
体電解質と空気極との接触においては、セル構造の幾何
学的な問題はあるが、数１より定性的な議論は充分可能
である。すなわち前記数１から反応率αは、拡散係数Ｄ
が小さいほど、また粉末の半径Ｒが小さいほど大きいこ
とがわかる。The following equation holds. Regarding the contact between the solid electrolyte and the air electrode in the fuel cell, there is a geometrical problem of the cell structure, but qualitative discussion is possible sufficiently from the equation (1). That is, the reaction rate α is calculated from the above equation 1 by the diffusion coefficient D
It is understood that the smaller the value is, and the smaller the radius R of the powder is, the larger.
【００３０】本発明におけるＬａＭｎＯ3 系導電性材料
自体の拡散係数Ｄは小さいために、化学反応性には優れ
たものであるが、本発明者は、さらに化学反応性を抑制
するため粉末の粒子サイズに着目し、上述の空気極材料
の作製条件を種々検討した結果、４μｍ以上の大きさの
固溶体粉末が活性が小さく、固体電解質との化学反応性
がさらに小さくなることを見出だしたのである。The LaMnO 3 -based conductive material of the present invention has a small diffusion coefficient D and is therefore excellent in chemical reactivity. However, the present inventor further investigated the powder particles to further suppress the chemical reactivity. As a result of various studies on the above-mentioned conditions for producing the air electrode material focusing on the size, it was found that the solid solution powder having a size of 4 μm or more has a small activity and further has a smaller chemical reactivity with the solid electrolyte. .
【００３１】即ち、本発明の製造方法によって得られた
導電性セラミックスは、固体電解質との接触において反
応性を小さく制御することができるのである。従って、
空気極表面に固体電解質を具備してなる燃料電池セルに
おいて、上記製法に基づき作空気極を作製しその表面に
固体電解質を形成することにより、燃料電池セルの製造
過程や燃料電池の高温作動時に空気極と固体電解質との
反応が抑制され、Ｌａ2 Ｚｒ2 Ｏ7 などの生成がなく、
セルの性能が劣化したり、固体電解質から空気極が剥離
するといった弊害を防止し、長期安定性に優れた燃料電
池セルを提供することができる。That is, the conductive ceramics obtained by the manufacturing method of the present invention can be controlled to have a small reactivity in contact with the solid electrolyte. Therefore,
In a fuel battery cell comprising a solid electrolyte on the surface of the air electrode, by producing an air electrode based on the above-mentioned manufacturing method and forming a solid electrolyte on the surface thereof, during the manufacturing process of the fuel cell or during high temperature operation of the fuel cell. The reaction between the air electrode and the solid electrolyte is suppressed, and La 2 Zr 2 O 7 is not generated,
It is possible to provide a fuel cell having excellent long-term stability by preventing harmful effects such as deterioration of cell performance and peeling of the air electrode from the solid electrolyte.
【００３２】[0032]
【実施例】次に、本発明を実施例に基づき説明する。 実施例１ 市販の純度９９．９％以上のＬａ2 Ｏ3 、Ｙ2 Ｏ3 、Ｃ
ａＣＯ3 、ＢａＣＯ3、Ｍｎ2 Ｏ3 を出発原料として、
これらを表１に示す組成になるように調合し、ジルコニ
アボ−ルを用いて１０時間混合した後、１２００〜１７
００℃で４〜１０時間固相反応させ、反応物をジルコニ
アボ−ルを用いて４〜２０時間粉砕し、約３〜１０μｍ
の粉末を得た。この後、この粉末にエチレングリコ−ル
を添加して混合しペ−ストを作製した。EXAMPLES Next, the present invention will be explained based on examples. Example 1 Commercially available La 2 O 3 , Y 2 O 3 and C having a purity of 99.9% or more.
Starting from aCO 3 , BaCO 3 , and Mn 2 O 3 ,
These were blended so as to have the composition shown in Table 1, mixed with a zirconia ball for 10 hours, and then mixed with 1200 to 17
Solid-phase reaction is carried out at 00 ° C. for 4 to 10 hours, and the reaction product is pulverized with a zirconia ball for 4 to 20 hours to obtain about 3 to 10 μm.
Of powder was obtained. Then, ethylene glycol was added to this powder and mixed to prepare a paste.
【００３３】一方、市販の純度９９．９％のＹＳＺ（１
０モル％Ｙ2 Ｏ3 含有）粉末を円板状に成形し、１４０
０℃で焼成して大きさ２０ｍｍφ、厚み２ｍｍで理論密
度比の９８％以上の円板状焼結体を作製した。このＹＳ
Ｚ円板に上記のペ−ストを約５０μｍの厚みで塗布した
後、１３００℃で１０時間焼成した。On the other hand, commercially available YSZ (1
Powder containing 0 mol% Y 2 O 3 ) is molded into a disc shape,
A disc-shaped sintered body having a size of 20 mmφ, a thickness of 2 mm and a theoretical density ratio of 98% or more was prepared by firing at 0 ° C. This YS
The above paste was applied to a Z disk in a thickness of about 50 μm, and then baked at 1300 ° C. for 10 hours.
【００３４】得られた積層体に対してさらに１４００℃
で４００時間焼鈍して加速試験を行い、試験後の積層体
に対して、ＹＳＺと導電性セラミックスとの界面をＥＰ
ＭＡを用いて分析し反応層であるＬａ2 Ｚｒ2 Ｏ7 の厚
みを測定した。その結果を表１に示した。The obtained laminated body is further subjected to 1400 ° C.
Annealed at 400 ° C for 400 hours for an accelerated test, and after the test, EP was applied to the interface between YSZ and the conductive ceramics.
The thickness of the La 2 Zr 2 O 7 is a reaction layer were analyzed using the MA was determined. The results are shown in Table 1.
【００３５】また、上記固溶体粉末を押出成形法により
外径１５ｍｍ、内径１１ｍｍ、長さ１００ｍｍに円筒状
に成形して、１５００〜１６００℃にて焼成し、開気孔
率が２５〜３０％の円筒状焼結体を得た。得られた焼結
体の導電率を測定したところ、いずれの試料も１０００
℃において５０〜８５ｓ／ｃｍの良導電性を示した。さ
らに、その円筒状焼結体を電気炉を用いて、大気中１２
００℃で１０００時間熱処理した後、円筒状焼結体の外
径の寸法測定を行い、熱処理前のそれと比較して下記数
２Further, the solid solution powder is formed into a cylindrical shape having an outer diameter of 15 mm, an inner diameter of 11 mm and a length of 100 mm by an extrusion molding method, and is fired at 1500 to 1600 ° C., and a cylinder having an open porosity of 25 to 30%. A sintered compact was obtained. The conductivity of each of the obtained sintered bodies was measured and found to be 1000
It showed a good conductivity of 50 to 85 s / cm at 0 ° C. Further, the cylindrical sintered body was heated in the atmosphere using an electric furnace.
After heat-treating at 00 ° C for 1000 hours, the outer diameter of the cylindrical sintered body was measured and compared with that before heat treatment,
【００３６】[0036]
【数２】 [Equation 2]
【００３７】に従い収縮率を算出し、その結果を表１に
示した。The shrinkage ratio was calculated according to the above, and the results are shown in Table 1.
【００３８】[0038]
【表１】 [Table 1]
【００３９】表１から明らかなように、固相反応の温度
が１４００℃より低い試料Ｎo.１、６、７、１１、１２
および固溶体粉末の平均粒径が４μｍより小さい試料Ｎ
o.１、２、６、１１では、Ｌａ2 Ｚｒ2 Ｏ7 の生成が顕
著であった。As is clear from Table 1, the samples No. 1, 6, 7, 11, 12 whose solid-state reaction temperature is lower than 1400 ° C.
And sample N having an average particle size of solid solution powder smaller than 4 μm
In o. 1, 2 , 6, and 11, the formation of La 2 Zr 2 O 7 was remarkable.
【００４０】実施例２ 市販の純度９９．９％以上のＬａ2 Ｏ3 、Ｙ2 Ｏ3 、Ｙ
ｂ2 Ｏ3 、Ｓｃ2 Ｏ3、Ｇｄ2 Ｏ3 、Ｅｒ2 Ｏ3 、Ｄｙ
2 Ｏ3 、Ｎｄ2 Ｏ3 、Ｓｍ2 Ｏ3 ＣａＣＯ3 、ＳｒＣＯ
3 、ＢａＣＯ3 、Ｍｎ2 Ｏ3 、ＮｉＯ、ＣｏＯ、ＺｒＯ
2 、ＣｅＯ2 、ＦｅＯ、Ｃｒ2 Ｏ3 を出発原料として、
これらを表２の組成になるように調合し、ジルコニアボ
−ルを用いて１０時間混合した後、１５５０℃で１０時
間固相反応させた。この粉末をジルコニアボ−ルを用い
て、さらに１０〜２４時間粉砕し，平均粒子径４〜８μ
ｍの固溶体粉末を得た。この後、この固溶体粉末を用い
て実施例１と同様にしてペーストを作製した後、実施例
１のＹＳＺ焼結体表面に塗布し１３００℃で１０時間焼
成した。Example 2 Commercially available La 2 O 3 , Y 2 O 3 and Y having a purity of 99.9% or more.
b 2 O 3, Sc 2 O 3, Gd 2 O 3, Er 2 O 3, Dy
2 O 3 , Nd 2 O 3 , Sm 2 O 3 CaCO 3 , SrCO
3 , BaCO 3 , Mn 2 O 3 , NiO, CoO, ZrO
2 , CeO 2 , FeO, Cr 2 O 3 as starting materials
These were blended so as to have the composition shown in Table 2, mixed with a zirconia ball for 10 hours, and then solid-phase reacted at 1550 ° C. for 10 hours. This powder was pulverized with a zirconia ball for 10 to 24 hours to obtain an average particle diameter of 4 to 8 μm.
A solid solution powder of m was obtained. Thereafter, a paste was prepared using this solid solution powder in the same manner as in Example 1, and then applied on the surface of the YSZ sintered body of Example 1 and fired at 1300 ° C. for 10 hours.
【００４１】得られた積層体に対してさらに１４００℃
で４００時間焼鈍して加速試験を行い、試験後の積層体
に対して、ＹＳＺと導電性セラミックスとの界面をＥＰ
ＭＡを用いて分析し反応層であるＬａ2 Ｚｒ2 Ｏ7 の厚
みを測定した。その結果を表２に示した。表２から明ら
かなように、いずれの試料においても反応相の厚みを３
５μｍ以下に抑制することができた。The obtained laminated body is further subjected to 1400 ° C.
Annealed at 400 ° C for 400 hours for an accelerated test, and after the test, EP was applied to the interface between YSZ and the conductive ceramics.
The thickness of the La 2 Zr 2 O 7 is a reaction layer were analyzed using the MA was determined. The results are shown in Table 2. As is clear from Table 2, the thickness of the reaction phase was 3
It could be suppressed to 5 μm or less.
【００４２】[0042]
【表２】 [Table 2]
【００４３】実施例３ 実施例１、２中のＮｏ．１，２，６，９，１５の固溶体
粉末を用いて円筒状に成形した後、１５００〜１５３０
℃で焼成し、平均細孔径１．０〜１．４μｍ、長さ２０
０ｍｍ、外径１６ｍｍ、内径１２ｍｍの一端が封じた円
筒状焼結体を作製し、空気極としての機能を有するセル
の支持管とした。この後、気相合成法により１１５０℃
で円筒状焼結体表面に厚さ約３０μｍのＹＳＺ（１０ｍ
ｏｌ％Ｙ2 Ｏ3 含有）を被覆し、さらにこの上にスラリ
−ディップ法により３０μｍの厚みに７０重量％のＮｉ
を含有したジルコニア（８ｍｏｌ％Ｙ2 Ｏ3 含有）から
なる燃料極を被覆し単セルとした。このセルを電気炉中
に保持し、セルの内側に酸素ガスを、外側に水素ガスを
流し、１０００℃で５００時間発電を行い、発電時間と
出力密度との関係を図３に示した。Example 3 Nos. In Examples 1 and 2 were used. After forming a solid solution powder of 1, 2, 6, 9, 15 into a cylindrical shape, 1500 to 1530
Baking at ℃, average pore size 1.0 ~ 1.4μm, length 20
A cylindrical sintered body having one end of 0 mm, an outer diameter of 16 mm, and an inner diameter of 12 mm was sealed to prepare a cell support tube having a function as an air electrode. After this, by vapor phase synthesis method, 1150 ° C
On the surface of the cylindrical sintered body, YSZ (10 m
ol% Y 2 O 3 contained) and further coated with 70% by weight of Ni to a thickness of 30 μm by a slurry-dip method.
A fuel cell made of zirconia (containing 8 mol% Y 2 O 3 ) containing was coated to form a single cell. This cell was held in an electric furnace, oxygen gas was flown inside the cell, and hydrogen gas was flown outside to generate power at 1000 ° C. for 500 hours. The relationship between power generation time and output density is shown in FIG.
【００４４】本発明のＮｏ．９，１５については、出力
密度はほとんど変化せず、発電後の反応相の厚みはいず
れも５μｍ以下であった。それに対して、粒径が４μｍ
以下の固溶体粉末である試料Ｎo.１、２、６を用いて作
製したセルでは時間とともに出力が低下し、発電後、固
体電解質と空気極との界面に３０〜４５μｍの反応相が
認められた。また、試料Ｎo.２は約３００時間後に支持
管が収縮してセルが破壊した。これより、本発明の優れ
た性能が認められた。No. 1 of the present invention. With respect to Nos. 9 and 15, the power density hardly changed, and the thickness of the reaction phase after power generation was 5 μm or less in all cases. On the other hand, the particle size is 4 μm
In the cells prepared using the following solid solution powders No. 1, 2, and 6, the output decreased with time, and after power generation, a reaction phase of 30 to 45 μm was observed at the interface between the solid electrolyte and the air electrode. . In Sample No. 2, the supporting tube contracted and the cell broke after about 300 hours. From this, the excellent performance of the present invention was recognized.
【００４５】[0045]
【発明の効果】以上説明したように、本発明によれば、
導電性セラミックスが固体電解質などと接触するような
場合においても、固体電解質との反応性を抑制すること
ができる。これにより、導電性セラミックスを固体電解
質型燃料電池セルの空気極として用いた場合において、
固体電解質と空気極との反応を抑え、長期安定性に優れ
た燃料電池セルを提供することができる。As described above, according to the present invention,
Even when the conductive ceramics come into contact with the solid electrolyte or the like, the reactivity with the solid electrolyte can be suppressed. Thereby, when the conductive ceramics is used as the air electrode of the solid oxide fuel cell,
It is possible to provide a fuel cell having excellent long-term stability by suppressing the reaction between the solid electrolyte and the air electrode.
【図１】円筒型燃料電池セルの構造を示す図である。FIG. 1 is a diagram showing a structure of a cylindrical fuel cell unit.
【図２】平板型燃料電池セルの構造を示す図である。FIG. 2 is a view showing a structure of a flat plate type fuel cell unit.
【図３】実施例３における発電時間と出力密度との関係
を示す図である。FIG. 3 is a diagram showing a relationship between power generation time and output density in Example 3.
１ 支持管 ２，７ 空気極 ３，６ 固体電解質 ４，８ 燃料極 ５ インタ−コネクタ ９ セパレ−タ 1 Support Tube 2,7 Air Electrode 3,6 Solid Electrolyte 4,8 Fuel Electrode 5 Inter-Connector 9 Separator
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｍ 8/02 Ｅ 9444−4Ｋ 8/12 9444−4Ｋ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical indication H01M 8/02 E 9444-4K 8/12 9444-4K
Claims (3)
アルカル土類元素および／または周期律表第３ａ族元素
を含むペロブスカイト型複合酸化物からなる導電性セラ
ミックスを製造する方法であって、前記金属の酸化物、
あるいは熱処理により酸化物を形成することのできる化
合物粉末を所定の割合で混合した後、該混合物を１４０
０℃以上で熱処理して平均粒径が４μｍ以上の固溶体粉
末を得、該固溶体粉末を所定の形状に成形した後、１１
００〜１６５０℃で焼成することを特徴とする導電性セ
ラミックスの製造方法。1. A method for producing a conductive ceramic comprising a perovskite-type complex oxide containing at least La and Mn and further containing an alcal earth element and / or an element of Group 3a of the periodic table, comprising: Oxide,
Alternatively, a compound powder capable of forming an oxide by heat treatment is mixed at a predetermined ratio, and then the mixture is mixed with 140
After heat treatment at 0 ° C. or higher, a solid solution powder having an average particle size of 4 μm or more is obtained, and the solid solution powder is molded into a predetermined shape.
A method for producing a conductive ceramic, which comprises firing at 00 to 1650 ° C.
１ 【化１】 で表され、式中、Ａは周期律表第３ａ族元素、Ｂはアル
カリ土類元素、ＣはＣｏ、Ｎｉ、Ｚｒ、Ｃｅ、Ｆｅ、Ｃ
ｒの群から選ばれた少なくも１種からなり、式中ｘ、
ｙ、ｚおよびｗが ０．２０≦ｘ＋ｙ≦０．７０ ０≦ｚ≦０．３０ ０．８８≦ｗ≦１．０５ を満足する請求項１記載の導電性セラミックスの製造方
法。2. The perovskite complex oxide is represented by the following chemical formula 1. In the formula, A is an element of Group 3a of the periodic table, B is an alkaline earth element, C is Co, Ni, Zr, Ce, Fe and C.
consisting of at least one selected from the group of r, where x,
The method for producing a conductive ceramic according to claim 1, wherein y, z and w satisfy 0.20 ≦ x + y ≦ 0.70 0 ≦ z ≦ 0.30 0.88 ≦ w ≦ 1.05.
カル土類元素および／または周期律表第３ａ族元素の各
金属酸化物、あるいは熱処理により酸化物を形成するこ
とのできる化合物粉末を所定の割合で混合した後、該混
合物を１４００℃以上で熱処理して平均粒径が４μｍ以
上の固溶体粉末を得、該固溶体粉末を所定の形状に成形
した後、１１００〜１６５０℃で焼成してペロブスカイ
ト型複合酸化物からなる導電性セラミックスを製造する
工程と、前記導電性セラミックスの表面に固体電解質膜
を形成する工程と、該固体電解質膜の表面に燃料極を形
成する工程とを具備する固体電解質型燃料電池セルの製
造方法。3. At least La and Mn, and further each metal oxide of an alcal earth element and / or an element of Group 3a of the periodic table, or a compound powder capable of forming an oxide by heat treatment in a predetermined ratio. After mixing, the mixture is heat-treated at 1400 ° C. or higher to obtain a solid solution powder having an average particle size of 4 μm or more, the solid solution powder is molded into a predetermined shape, and then fired at 1100 to 1650 ° C. to perovskite-type composite oxidation. Solid-electrolyte fuel cell comprising a step of producing a conductive ceramics composed of a material, a step of forming a solid electrolyte membrane on the surface of the conductive ceramics, and a step of forming a fuel electrode on the surface of the solid electrolyte membrane Cell manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05227462A JP3091064B2 (en) | 1993-09-13 | 1993-09-13 | Method for producing conductive ceramics and method for producing solid oxide fuel cell |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05227462A JP3091064B2 (en) | 1993-09-13 | 1993-09-13 | Method for producing conductive ceramics and method for producing solid oxide fuel cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0782023A true JPH0782023A (en) | 1995-03-28 |
| JP3091064B2 JP3091064B2 (en) | 2000-09-25 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP05227462A Expired - Fee Related JP3091064B2 (en) | 1993-09-13 | 1993-09-13 | Method for producing conductive ceramics and method for producing solid oxide fuel cell |
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| JP (1) | JP3091064B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011103211A (en) * | 2009-11-10 | 2011-05-26 | Toto Ltd | Solid electrolyte fuel cell |
-
1993
- 1993-09-13 JP JP05227462A patent/JP3091064B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011103211A (en) * | 2009-11-10 | 2011-05-26 | Toto Ltd | Solid electrolyte fuel cell |
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| Publication number | Publication date |
|---|---|
| JP3091064B2 (en) | 2000-09-25 |
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