JPH03203166A - Manufacture of solid electrolyte membrane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application Method of the Invention Solid Electrolyte Fuel Cell The present invention relates to a method for producing a solid electrolyte membrane used in electrochemical devices such as solid electrolyte oxygen sensors and oxygen pumps.

Conventional technology In conventional electrochemical devices of this type, ysz <yttria-stabilized zirconia) is commonly used as a solid electrolyte. For example, thermal spraying has a large film forming speed and is suitable for mass production; When used as an electrochemical device, it often causes gas leaks and insufficient properties, or if the film is thin, it often causes electrode short circuits.9 Mana Solid Electrolyte Membrane If the electrode material is an oxide, it may react with the solid electrolyte to form an inert substance at the interface between the solid electrolyte and the electrode.
In the case of platinum electrodes, this method cannot be said to be suitable because it causes problems such as excessive sintering and a significant decrease in surface area. A porous solid electrolyte membrane is impregnated with a solution prepared by uniformly dispersing it and fired, thereby making the membrane dense.

Effects of the present invention A solid electrolyte membrane prepared by a conventional method can be densified by a simple method, but a highly reliable electrochemical device can be obtained without causing disadvantages such as reaction with electrodes or reduction in electrode area. Embodiment Figure 1 is a schematic diagram showing the cross-sectional structure of the solid electrolyte membrane according to the present invention, and shows the state after being impregnated with a solid electrolyte fine powder dispersion solution and dried. Amo l is Ni in advance
/YSZ-based electrode 3 is formed on a porous substrate 4 made of calcia-stabilized zirconia.
The porous solid electrolyte 11L2, which forms the framework by attaching 8mo 1% Y20□> powder by plasma spraying, is made by dispersing YSZ fine particles (30
YSZ adhered to the inside of the pores of the porous solid electrolyte membrane, which becomes the framework, by impregnating the aqueous solution (wt%) under reduced pressure.
Even with the fine particles of The solid electrolyte membrane prepared in this manner is shown below as a schematic diagram showing how the YSZ particles sinter and fill the pores of the porous sprayed membrane after firing (2'). First, in order to quantitatively understand the effect of impregnation treatment with YSZ fine particles, the porosity of the solid electrolyte membrane was determined.
．． The porosity of the porous solid electrolyte membrane when fired at 1300° C. without impregnation treatment was approximately 23% (this value does not change much even without firing). For this, impregnation treatment is performed.1. % and when fired at 1300℃, the porosity decreases to about 2%. It is thought that because the YSZ particles were sufficiently small, sintering progressed even at such a low temperature, and most of the pores in the porous sprayed film were filled with semi-molten YSZ.

- 5rZr was used at the interface between the solid electrolyte and (LaSr)MnOs-based electrode after force-pulling firing, which required a firing temperature of approximately 1600°C to achieve a porosity of 2% without mechanical impregnation.
It was observed that high-resistance substances such as O* and La*Zr*Qv were generated.If only impregnation was performed and no firing was performed, f1 porosity was approximately 7%, and even if only fine particles were impregnated, Did it become clear that the effect of densification of the membrane is large? ,
By further reducing the particle size of the YSZ fine particles, it is possible to further promote densification through impregnation, and by firing the particles, it is also possible to reduce the porosity to approximately 0%.

Furthermore, the impregnation treatment not only contributes to the densification of the solid electrolyte membrane, but also has the effect of the YSZ fine particles acting as a leg material at the bonding interface between the solid electrolyte and the electrode, and has the effect of significantly improving the bonding property between the solid electrolyte and the electrode. To actually confirm this effect, a laminate and impregnated sail 1' were subjected to the same impregnation and firing treatment as described above.
Air + 4 = 1. R
The laminate was subjected to a heat leak test (30 times in a row) at T ~ 1000℃ (temperature increase/decrease at 300℃/h), and the presence or absence of separation between the solid electrolyte and electrodes was analyzed by observing the cross section of the laminate after the test. Nest Go to impregnation treatment and 130
In the case of samples fired at 0°C, no abnormalities were observed at the bonding interface between the solid electrolyte and the electrodes. However, in the samples that were not impregnated, part of the electrodes peeled off or microscopic particles formed on the electrodes. Occasionally cracks were observed.
It can also be seen that the fine particle impregnation and calcination treatment has a remarkable effect on the densification of the solid electrolyte membrane.

In the above examples (L) Force exchange using YSZ (Ittria stabilized zirconia) as a solid electrolyte, but not limited to this, L) Particle size of YSZ powder used for thermal spraying,
The particle size of the YSZ fine particles for impregnation can also be set appropriately. For impregnation, an aqueous solution is used. Additives may be used to adjust the dispersion state of the particles, and solvents that are not available near water can be used. Impregnation can also be done using a variety of methods. Can be set freely. The porous membrane of the solid electrolyte may be a plasma-sprayed membrane, or it may be a membrane made by other methods of thermal spraying, and it may also be a porous sintered body or a porous sintered body made by other methods such as slurry coating. is also applicable in the same way.

Effects of the Invention According to the present invention, a porous solid electrolyte membrane can be densified by a simple method, and a highly reliable electrochemical device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the process of producing a dense film using a production method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the produced dense film. l...Solid electrolyte particles (porous membrane skeleton), 2...Solid electrolyte fine particles (impregnating material), 2'...Sintered fine particles 3.
・Severe condition 4..Substrate 5..Electrode

Claims (1)

[Claims] A method for producing a solid electrolyte membrane, which comprises impregnating a porous solid electrolyte membrane with a solution prepared by uniformly dispersing solid electrolyte fine particles in advance and baking the membrane to densify the solid electrolyte membrane.