JPS62268063A - Manufacture of solid electrolyte - Google Patents

Abstract

PURPOSE:To make a solid electrolytic layer having the desired thickness and the degree of sealing securable in an efficient manner, by forming the solid electrolytic layer on the electrode layer formed on the surface of a porous base material in advance by means of thermal spraying process, performing chemical evaporation on the surface and simultaneously carrying out the sealing, and forming a film by a porous electrode material, on this sealed surface. CONSTITUTION:Nickel oxide as a fuel electrode 3 is deposited to the surface of a porous base material by means of an acetylene thermal spraying process, and furthermore powder of partially stabilized yttria system zirconia is deposited to this outer layer by means of a plasma thermal spraying process, forming a thin film. Before a chemical evaporation is formed on to of this film, gas containing hydrogen and water is made to flow to the porous base material side 7 and also zirconium chloride and yttrium chloride both are made to flow to the surface side 8 of a thermal spraying layer 4, thus evaporation reaction is carried out. Lanthanum cobalt (LaCoO3) series is laminated to a still upper layer on the layer of this oxided 5 by means of the acetylene thermal spraying process, constituting an air electrode 6, formation of the fuel electrode 3 and this air electrode 6 is reversible at need.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a solid electrolyte used as an electrode for a high-temperature solid electrolyte fuel cell or a high-temperature electrolyzer.

[Conventional technology]

As a method of constructing a high-temperature solid oxide fuel cell, there is a method using a thermal spraying method, as shown in FIG.

In this case, the number of layers forming the solid electrolyte is 200 to 50.
Unless the thickness is 0 μm, gas leakage cannot be prevented, and in some cases, leakage may occur even under a pressure of 10 m of water column, causing direct combustion of fuel and air, which not only significantly reduces efficiency but is also dangerous. Also, the thickness is 200 to 300 μm
This is because when used as a fuel cell, the resistance to ion conduction is large and it is desirable to make the material thinner.

On the other hand, as another method, an electrochemical vapor deposition method has been proposed as shown in Figure 3. Although this method can completely seal the pores and form a thin film, it is insufficient to form a reliable solid electrolyte for batteries. It is extremely time consuming and nearly impossible to produce solid electrolyte materials in large quantities.

In FIG. 2, 01 is a porous base material made of, for example, alumina (A403) with a thickness of about 4 cm, and 02 is the ventilation hole, which accounts for 20 to 30% of the total. Approximately 70 to 10 nickel oxide (N10) is applied to this surface as the fuel electrode 03.
Attached by 0μm acetylene spraying. 200mm by plasma spraying on top of this. Partially stabilized zirconia [: (zroz)ate(cao) with a thickness of um~300μm
) at ) is attached as the solid electrolyte 04. Furthermore, the upper layer 06 is an air electrode with a thickness of 100 to 20
0 μm of lanthanum chromic acid (LaCr03) was applied by acetylene spraying.

Next, in FIG. 3, a 2-thick calcia-based partially stabilized zirconia [(ZrOt)a, (CaO)at) is used as a porous base material 01a, and the upper layer is a [1,7-] air electrode. 06a, lanthanum manganic acid (L a MTI
02) was applied as a slurry and then sintered.

Moreover, ) Δtetriate partially stabilized zirconia [
:(ZrOz)ass(YtOi)ate) is electrochemically deposited to form a solid electrolyte layer 05a of 40 to 50 μm, and a fuel electrode 05a of 50 μm is formed on top of the solid electrolyte layer 05a.
It is formed by coating and sintering Ni (Ni/N1p).

[The problem that the invention attempts to solve]

In order to apply solid electrolytes to fuel cells, it is necessary to form solid electrolytes as thin as possible.

Furthermore, since fuel and air gas exist on both sides of the solid electrolyte via porous electrodes, there must be no ventilation (leakage) between them. Conventional thermal spraying methods cannot meet this requirement as described above.

In order to obtain high output by combining a large number of batteries, it is necessary to withstand back pressure of several kg/e. It is necessary to establish a mass production method to construct the structure, and conventional electrochemical deposition methods are extremely slow in forming thin films, and are expensive to obtain the required thickness, so it is necessary to speed up the thin film forming speed. has been done.

The present invention aims to provide a method for producing a solid electrolyte that can overcome the drawbacks of the above-mentioned conventional methods.

[Failure to solve the problem]

The present invention includes: (1) forming pores (electrode material is coated on the surface of a porous base material by thermal spraying); (2) solid electrolyte material powder is thermally sprayed onto the surface of the electrode material so as to occupy most of the planned thickness; A second step of forming a solid electrolyte layer with a certain thickness ■ A third step of chemically depositing a solid electrolyte material on the surface of the solid electrolyte layer to make the thickness of the solid electrolyte layer the planned thickness, and at the same time sealing the layer. and■ Porous @ on the surface of the solid electrolyte layer sealed above
This is a solid electrolyte manufacturing method characterized by comprising a fourth step of forming an electrode material by coating or thermal spraying.

That is, in the present invention, 80 to 95% of a solid electrolyte is first sprayed onto an electrode layer formed on the surface of a porous material by a thermal spraying method.
The basic idea is to form a solid electrolyte with a diameter of 50 to 35 .mu.m, which corresponds to 50 to 35 .mu.m, to perform chemical vapor deposition using its porosity, and to complete the solid electrolyte formation operation when the pore sealing is completed.

[Effect]

The present invention skillfully combines conventional thermal spraying methods and chemical vapor deposition methods to efficiently produce a solid electrolyte layer having a desired thickness and degree of sealing.

In the present invention, the porous base material is At20seCS
Z (Calcia 5tabilized Zrc
onia, calcia stabilized zirconia), etc., as electrode materials, air electrodes such as LaCoO3-based, LaMnO3-based, etc., fuel electrodes such as Ni, Ni-ZrO2 cermet, etc., and solid electrolytes such as C3Z, YSZ (yttoria-stabilized zirconia), etc. etc. are used.

〔Example〕 An embodiment of the present invention will be explained with reference to FIG.

No. 1 was a porous base material, which was an alumina (8403) plate with a thickness of one gourd and a porosity of 20%. Length 40 as required
6 (158) or a tube with a bottom can be used, and the porous material of partially stabilized zirconia ceramics shown in the conventional method can be used as the base material. 2 is the pore portion.

Nickel oxide (N10) was applied to this surface as a fuel electrode 3 to a thickness of about 50 μm by acetylene spraying, and partially stabilized Ittriya-based zirconia powder was welded to this surface layer by plasma spraying to give an average thickness of 40 to 45 μm. . The powder had a mixed composition of (ZrOz)up/(YzOs)u+ and had an average particle size of 10 μm or less.

Before forming a chemical vapor deposition layer thereon, a gas containing hydrogen and water is flowed on the porous substrate side 7, and zirconium chloride and yttrium chloride are flowed on the surface side 8 of the thermal sprayed layer 4 at a molar ratio of about 10:1. A vapor deposition reaction was carried out by heating to 1200°C.

Z r C4+ 2820 →ZrO2+4HC2■2
YC13+3H20-I-Yz(% +6HCt
(2) These two types of reactions occur on the surface of the thermally sprayed layer 4, and the oxide 5, which is a υ product, is deposited and the pores are eventually sealed.

After the pores are sealed, a difference in oxygen partial pressure occurs between the surface side of the oxide 5 and the base material side, forming an oxygen concentration battery, and O! +4e →20− Or that occurs in the reaction of (2) moves and forms Z r C14+ on the surface side of oxide 5.
40”-4Z r 01 + CI4 + 8 e
■2YCLs + 302″″ →Y203 +
3 C4+ 6 e The following reaction occurs and it grows.

When the temperature is high and the oxygen partial pressure is low, electron conductivity appears in the layer of oxide 5, so that electron compensation is performed. However, since the moving speed of electrons in the opposite direction to the moving direction of oxygen ions is slow, it is inefficient to obtain 50 layers of oxide with a predetermined thickness only by this reaction. In the present invention, since the reaction ends when the pressure resistance is satisfied, this reaction is not necessary or can be stopped early.

Further above this layer of oxide 5, lanthanum cobaltite (LaCo03) is applied by spraying with acetylene to a thickness of 100 μm.
The air electrode 6 is formed by stacking layers.

If necessary, the configurations of the fuel electrode 3 and air electrode 6 can be reversed.

When hydrogen or carbon oxide is supplied together with a small amount of water vapor to the side 7 of the porous substrate 1 constructed in this way, and air is supplied to the side 8 of the air electrode 6 to maintain the entire body at 1000°C. When the fuel electrode 3 and the air electrode 6 are connected by a conductor Bq t 1o, a so-called fuel cell is constructed which can obtain direct current electricity.

At this time, the reaction 02 + 4p #20- (2) occurs in the air j6, and the oxygen ions move through the solid of the oxide 5 and sprayed layer 4 in Fig. 1, which constitute the solid electrolyte, by ion conduction. It reaches the fuel electrode 3. For fuel type 3, conductor) 0,9
The reverse reaction of the formula ■ occurs when the electrons that have moved on the outside are received, and further, the reaction as a fuel cell is completed by the reaction of 2Hz + 0□4 2H,0■ 2 Co + Oz, : 2 CO2■ .

Further, when direct current electricity is supplied to the connections 9 and 10, the above formula (1) or (0) is performed in reverse, and the device can also be used as a so-called high@electrolysis device in which oxygen ions can be taken out as oxygen at the air electrode 6.

〔Effect of the invention〕

1) A thin film type solid electrolyte, which could not be obtained by conventional thermal spraying methods, can be obtained.

2) Furthermore, chemical vapor deposition allows complete sealing, and when used in an integrated manner, there is no leakage and safety even when sufficient pressure is applied.

5) It is extremely easy to use and the productivity of the conventional chemical vapor deposition method can be significantly improved.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the structure of the solid electrolyte of the present invention, Figure 2 is a schematic diagram showing the structure of the solid electrolyte of the present invention.
FIG. 5 is a schematic diagram showing the structure of a solid electrolyte manufactured by a conventional method. Figure 1 8 Air Figure 2 Procedural Amendments September 9, 1986

Claims (4)

[Claims] (1) A first step of forming a porous electrode material on the surface of a porous base material by coating or thermal spraying, (2) A second step of spraying solid electrolyte material powder onto the surface of the electrode material to form a solid electrolyte layer with a thickness that accounts for most of the planned thickness. (3) a third step of chemically depositing a solid electrolyte material on the surface of the solid electrolyte layer to bring the thickness of the solid electrolyte layer to the planned thickness and simultaneously sealing the layer; (4) A method for manufacturing a solid electrolyte, comprising a fourth step of forming a porous electrode material on the surface of the solid electrolyte layer subjected to the sealing treatment by coating or thermal spraying.