CN1750307A - Anode-loaded double-layer electrolyte membrane for solid oxide fuel cell and preparation method thereof - Google Patents

Abstract

The invention relates to an anode-loaded double-layer electrolyte membrane of a solid oxide fuel cell and a preparation method thereof, and relates to the technical field of fuel cells. The anode supports a double-layer electrolyte membrane, which is composed of an anode and an electrolyte membrane, and two layers of electrolyte membranes are fixedly connected to one side of the anode. The two layers of electrolyte membrane, one is a blocking reaction layer, and the other is an electronic conduction blocking layer. The preparation method is that the barrier reaction layer and the electron conduction barrier layer are sequentially fixed on one side of the anode, and after co-sintering and densification at high temperature, the cathode is fixed on the other side of the electron conduction barrier layer to obtain a membrane electrode. Three-in-one components, and then assembled into a medium temperature solid oxide fuel cell. The medium-temperature solid oxide fuel single cell with an anode-loaded double-layer electrolyte film prepared by the invention has higher cell efficiency and performance than a GDC thin-film cell with the same thickness, and its power density is about twice that of a traditional LSGM thin-film cell.

Description

Anode-loaded double-layer electrolyte membrane for solid oxide fuel cell and preparation method thereof

technical field

The invention relates to the technical field of fuel cells, in particular to an anode-loaded double-layer electrolyte membrane of a medium-temperature solid oxide fuel cell and a preparation method thereof.

Background technique

At present, the thin film of the new electrolyte is a major obstacle to the high performance of intermediate temperature solid oxide fuel cells.

In the document "Journal of The Electrochemical Society, 2002, 149(9): A1132-A1135", J.W Yan et al. avoided the reaction of LSGM with NiO at high temperature by impregnation method, and prepared anode-loaded LSGM thin film batteries. However, there are disadvantages of low open circuit potential and low output power.

In the document "Materials Research Bulletin, 1999, 34(12/13): 2027-2034", Marko Hrovat et al. used LSGM electrolyte as an electron conductance barrier layer for research and found that the lanthanum element in the LSGM layer migrated to the GDC layer. As a result, a new phase Ce _1-x La _x O _2-x/2 is formed in the GDC layer, and a new phase SrLaGa ₃ O ₇ is formed in the LSGM layer.

In the literature "Solid State Ionics, 2003, 159, 209-216", N. Maffei et al. studied the reaction of the internal interface of the LSGM electrolyte assembly supported by the NiO-CeO ₂ anode. The study found that the Ni in the anode increases with the temperature The more serious the diffusion to the electrolyte region, at the same time, it was also found that the La element in the electrolyte also appeared in the anode.

To sum up: 1. The open-circuit voltage of CeO ₂ -based electrolyte thin-film batteries decreases due to the easy generation of electronic conductance in a reducing atmosphere, thereby reducing the efficiency of the battery. However, _LaGaO3 -based electrolyte thin-film batteries are difficult to prepare by conventional methods due to compatibility problems and complex composition. _LaGaO3 -based electrolyte thin-film batteries prepared by high-temperature sintering and impregnation have higher anode overpotential, open circuit potential and output power density. Low. Therefore, there is currently a problem of thin film thinning of new electrolytes. Using any one of these thin-film electrolyte batteries alone cannot obtain a single cell with ideal performance and efficiency.

2. In terms of existing double-layer electrolyte batteries, there are mainly YSZ and GDC double-layer electrolytes to try to thin the GDC electrolyte, but because the conductivity of YSZ is much lower than that of GDC and LSGM electrolyte materials, compared with using YSZ thin-film batteries alone , the performance degrades instead. If the YSZ film is made thinner, the uniformity will be affected, the electron conduction of the GDC electrolyte cannot be completely blocked, and the efficiency of the battery will decrease.

3. Another double-layer electrolyte thin-film battery tried to use GDC and LSGM electrolytes, but due to the chemical compatibility problems of the two electrolytes at high temperatures, a high-resistance phase was generated at the interface. Therefore, the battery basically has no output performance.

In conclusion, the _CeO2- based electrolyte is prone to electronic conduction under reducing atmosphere by itself, resulting in a decrease in cell efficiency. However, due to its complex composition, LaGaO ₃ -based electrolytes are difficult to use traditional thin film preparation methods to prepare thin films. At the same time, LaGaO ₃ -based electrolytes are prone to chemical reactions with traditional anode materials at high temperatures, and there are compatibility problems.

The thin film of the electrolyte is mainly realized by the progress of the preparation technology to realize the thin film of the new electrolyte. However, the results after thinning are still unsatisfactory. The open circuit potential of CeO2 _- based electrolyte thin film batteries is less than 0.9V when the temperature reaches above 600 °C, while the open circuit potential and performance of _LaGaO3 based thin film electrolyte batteries prepared by impregnation method are not ideal.

Contents of the invention

The purpose of the present invention is to use _CeO2- based and _LaGaO3 -based electrolyte materials at the same time through material selection, utilize _CeO2 -based electrolytes to eliminate the chemical compatibility of LaGaO3 _- based electrolyte materials with anodes, and utilize the pure ions of _LaGaO3 -based electrolytes conductivity to block the electronic conductance of _CeO2- based electrolytes to prepare a novel thin-film electrolyte battery with an anode-supported two-layer structure.

To achieve the above object, the technical solution of the present invention is to provide an anode-loaded double-layer electrolyte membrane for a solid oxide fuel cell, which is composed of an anode and an electrolyte membrane, and two layers of electrolyte membrane are fixedly connected to one side of the anode.

The anode-loaded double-layer electrolyte membrane, the two-layer electrolyte membrane, one is a barrier reaction (LDC) layer, the other is an electron conductance barrier (LSGM) layer, and one side of the barrier reaction layer is solidified with one side of the anode. connected, the other side is fixedly connected with the side of the electron conduction barrier layer, and the other side of the electron conduction barrier layer is fixedly connected with the cathode.

The anode-loaded double-layer electrolyte membrane, the two-layer electrolyte membrane, wherein, the barrier reaction layer adopts the electrolyte material La _x Ce _1-x O ₂ , and the electron conductance barrier layer adopts the electrolyte material La _y Sr _{1-y Gaz} Mg _1-z O ₃ , which must conform to the relationship of y=2x, so as to ensure the same content of La element.

In the anode-supported double-layer electrolyte membrane, any electrolyte membrane in the two-layer electrolyte membrane is dense to achieve the purpose of gas barrier.

The anode-loaded double-layer electrolyte membrane, the anode, is made of metal composite ceramics, wherein the metal catalyst includes Ni, Co, Cu, Rh, Fe, Pt, Pd, Mo, Ti; in the metal composite ceramics, the oxide Material ceramics include Y ₂ O ₃ stabilized ZrO ₂ (YSZ), Gd ₂ O ₃ doped CeO ₂ (GDC), La ₂ O ₃ doped CeO ₂ (LDC), Sm ₂ O ₃ doped CeO ₂ (SDC), Sc ₂ O ₃ stabilized ZrO ₂ (ScSZ).

The anode supports the double-layer electrolyte membrane, and the cathode is made of La _x Sr _1-x CoO ₃ , Sm _x Sr _1-x CoO ₃ , La _x Sr _1-x MnO ₃ , La _x Ni _{1- x} FeO ₃ .

A method for preparing an anode-loaded double-layer electrolyte membrane as claimed in claim 1, comprising the following steps:

a) Prepare the anode substrate, _CeO barrier reaction (LDC) layer and electron conductance barrier (LSGM) layer by common techniques for the next step;

b) one side of the _CeO barrier reaction (LDC) layer is affixed to one side of the anode substrate by conventional techniques;

c) with the usual technique, one side of the electron conductance barrier (LSGM) layer is affixed to the CeO on the _other side of the barrier reaction (LDC) layer;

d) After the semi-finished product obtained in step c) is co-sintered and compacted at high temperature, an anode electrolyte two-in-one component is obtained.

e) The cathode is fixedly connected to the other side of the electronic conductance barrier (LSGM) layer by common techniques, and after sintering at an appropriate temperature, a membrane-electrode three-in-one component is obtained.

In the preparation method, the commonly used techniques in steps a), b) and c) are traditional anolyte two-in-one preparation techniques, including dry pressing, screen printing, coating, casting, film rolling, Any one of a group of processes for scraping film.

Described preparation method, the commonly used technology in its described e) step is traditional cathode preparation technology, is any one of a group of processes of screen printing, coating, sputtering, plasma spraying, electrochemical deposition, chemical deposition kind.

The excellent effect of the present invention is:

1. By using a double-layer electrolyte, the adverse chemical reaction between the electronic conductance barrier layer (LSGM) and the anode material is avoided at high temperature, and the electronic conductance of the barrier reaction layer (LDC) is also blocked by the pure ion conductor LSGM layer. The disadvantages of using any one of the electrolyte materials alone as thin film batteries are solved.

2. In the present invention, the double-layer electrolyte is used as the electrolyte, so that it is only necessary to ensure that one layer of electrolyte achieves the purpose of gas barrier when preparing a single cell, which reduces the requirement on the sintering temperature during the preparation process.

3. Using a new type of electrolyte material to replace the traditional low-conductivity YSZ to prepare an anode-loaded thin-film battery, which greatly improves the performance of the battery at the same temperature. At the same time, the thickness of the film can be greatly increased under the same performance, which greatly improves the battery. Mechanical strength.

4. The preparation method can adopt a variety of film-making technologies. It can be used in flat, tubular and corrugated solid oxide fuel cells.

5. In the present invention, the prepared anode-loaded double-layer electrolyte thin film medium-temperature SOFC single cell has an open circuit potential much higher than that of an LDC layer thin film cell alone, and a maximum output power density higher than that of an LSGM thick film cell.

6. In the present invention, the prepared anode-loaded double-layer electrolyte thin-film medium-temperature SOFC single cell has higher cell efficiency and performance than a GDC thin-film cell with the same thickness, and its power density is about twice that of a traditional LSGM thin-film cell.

Description of drawings

Fig. 1 is a structural diagram of the anode-supported double-layer electrolyte membrane of the present invention.

Detailed ways

The invention prepares the anode-loaded thin-film double-layer thin-film battery, adopts electrolyte materials LDC and LSGM with relatively high electrical conductivity and good high-temperature compatibility, and at the same time, the LSGM electrolyte material has good compatibility with most cathode materials with excellent performance, and LDC The electrolyte material has good compatibility with the traditional materials of the anode.

The anode-loaded double-layer thin-film battery prepared by using the two electrolyte materials adopted in the present invention has achieved very high performance when the total thickness of the electrolyte is 100 microns, which is higher than that of the improved thick-film LSGM battery. It is also higher than the performance of LSGM thin film batteries prepared by impregnation method. The open circuit potential is higher than that of the GDC thin film battery, reaching about 1.1V at 700°C, which is close to the theoretical value. At the same temperature, the efficiency is higher than that of GDC thin film batteries. The experimental results show that after the new electrolyte is thinned, no bad results are produced. The LDC electrolyte eliminates the compatibility issue between the anode material and the LSGM electrolyte, while the LSGM electrolyte blocks the electronic conductance of the LDC electrolyte. Make high-performance electrode materials applied to solid oxide fuel cells.

In order to avoid the chemical reaction between the electrolyte separator and the anode substrate during the firing and densification of the LSGM film, while using the LDC electrolyte, it is necessary to block the electronic conductance under its reducing atmosphere. Therefore, two electrolyte materials are used at the same time, and the reaction between LSGM and the anode is isolated by adding the LDC layer, and the use of the LSGM layer can block the electronic conductance of the LDC layer. Moreover, both electrolyte materials have much higher conductivity than YSZ.

As shown in Figure 1, it is the structure of the anode-loaded double-layer electrolyte membrane of the present invention. The anode-supported bilayer electrolyte membrane is a three-in-one component of an intermediate-temperature solid oxide fuel cell (SOFC). The anode-loaded double-layer electrolyte film includes a La-doped CeO ₂ (LDC) layer 2 adjacent to the anode 1 and an LSGM layer 3 adjacent to the cathode 4 . The LDC layer 2 is a barrier reaction layer, which requires completely avoiding the reaction between the anode material and the LSGM layer 3 at high temperature; the LSGM layer 3 is an electron conductance barrier layer, which requires lower electron conductance. During the preparation process, one of the two layers of electrolyte is required to have a dense electrolyte membrane to achieve the purpose of gas barrier. At the same time, the double-layer electrolyte membrane, wherein the barrier reaction layer 2 uses the electrolyte material La _x Ce _1-x O ₂ , and the electron conductance barrier layer 3 uses the electrolyte material La _y Sr _1-y Ga _z Mg _1-z O ₃ , which must meet y=2x relationship to ensure the same content of La element. The anode 1 is a metal composite ceramic, and the metal catalyst in the metal composite ceramic includes Ni, Co, Cu, Rh, Fe, Pt, Pd, Mo, Ti; and the oxide ceramic includes YSZ, GDC, LDC, SDC, ScSC. Cathode 4, the cathode material of which is La _x Sr _1-x CoO ₃ , Sm _x Sr _1-x CoO ₃ , La _x Sr _1-x MnO ₃ , La _x Ni _1-x FeO ₃ .

A method for preparing an anode-loaded double-layer electrolyte film, comprising the following steps:

a) The anode substrate, CeO barrier reaction (LDC) layer ₂ and electron conductance barrier (LSGM) layer 3 were prepared by common techniques for the next step.

b) One side of the CeO ₂ barrier reaction (LDC) layer 2 is affixed to one side of the anode substrate by common techniques.

c) Using common techniques, one side of the electronic conductance barrier (LSGM) layer 3 is affixed to the other side of the CeO ₂ barrier reaction (LDC) layer 2 .

d) The semi-finished product obtained in step c) is co-sintered and compacted at high temperature to obtain a two-in-one component of anode and electrolyte.

e) The cathode 4 is fixedly connected to the other side of the electronic conductance barrier (LSGM) layer 3 by common techniques, and after sintering at an appropriate temperature, a membrane-electrode three-in-one component is obtained.

f) performing other conventional processes to complete the assembly of the solid oxide fuel cell.

The two-in-one preparation of the anode substrate and the _CeO2 barrier reaction (LDC) layer 2 and the electronic conductance barrier (LSGM) layer 3 uses the traditional membrane-electrode two-in-one preparation technology, including dry pressing, screen printing, coating, flow Common techniques such as extension, rolling, scraping, sputtering, plasma spraying, electrochemical deposition, and chemical deposition.

The commonly used technique described in step e) of the method is a traditional cathode preparation technique, which is any one of a group of processes such as screen printing, coating, sputtering, plasma spraying, electrochemical deposition, and chemical deposition.

Solid oxide fuel cells have attracted worldwide attention because they do not use precious metal materials, have a wide range of fuel applications, and have high power generation efficiency. The present invention solves the obstacle of thin film of the new electrolyte, greatly promotes the application of the new electrolyte, and improves the compatibility between the electrolyte and the cathode. The anode material also uses cerium oxide material with good catalytic activity for hydrocarbon fuels, so that the present invention The invented three-in-one adopts existing high-performance materials, which can meet the performance requirements of solid oxide fuel cells at medium temperature, and provide a basis for the commercialization of medium temperature solid oxide fuel cells.

The invention can make the signal of the high-temperature oxygen sensor more sensitive, so it is expected to replace the existing low-conductivity material and be adopted. It can also be used in membrane reactors to improve reaction efficiency and yield.

The present invention can be applied to any type of three-in-one assembly of medium and high temperature solid oxide fuel cells, including flat, tubular, corrugated and single-chamber solid oxide fuel cells.

It can also be applied to various types of oxygen sensors under high temperature.

It can also be applied to high-temperature inorganic oxygen-permeable membrane reactors.

Example 1

The anode-loaded double-layer electrolyte thin film battery prepared by dry pressing method uses GDC/NiO as the anode substrate, and the cathode material is LSC/LDC. At 800°C, when hydrogen is used as fuel and air is used as oxidant, the open circuit voltage can reach above 1.02V. , the maximum output power density reaches above 1.1W/cm ² .

Example 2

The anode-loaded double-layer electrolyte thin film battery prepared by dry pressing method uses GDC/NiO as the anode substrate, and the cathode material is pure LSC. At 800°C, when hydrogen is used as fuel and air is used as oxidant, the open circuit voltage reaches 1.02V or more. The maximum output power density reaches above 1.5W/cm ² .

Example 3

Using the same material as in Example 2, the anode-loaded double-layer electrolyte thin film battery prepared by the scraping method, at 800 ° C, when hydrogen is used as fuel and air is used as oxidant, the open circuit voltage reaches above 0.82V, and the maximum output power density reaches 0.55W/cm ² or more.

Claims (9)

1. An anode-loaded double-layer electrolyte membrane of a solid oxide fuel cell, consisting of an anode and an electrolyte membrane, is characterized in that: one side of the anode is fixedly connected with two layers of electrolyte membranes. 2. The anode-supported double-layer electrolyte membrane as claimed in claim 1, characterized in that: the two-layer electrolyte membrane, one is a blocking reaction (LDC) layer, and the other is an electron conductance blocking (LSGM) layer, and the blocking reaction layer One side of the anode is fixedly connected to one side of the anode, the other side is fixedly connected to the side of the electron conduction barrier layer, and the other side of the electron conduction barrier layer is fixedly connected to the cathode. 3. The anode-loaded double-layer electrolyte membrane as claimed in claim 1 or 2, characterized in that: the two-layer electrolyte membrane, wherein the barrier reaction layer adopts the electrolyte material La _x Ce _1-x O ₂ , and the electron conduction barrier layer The electrolyte material LaySr _1-y Ga _z Mg _1-z O ₃ is used, which must meet the relationship of y=2x to ensure the same content of La element. 4. The anode-supported double-layer electrolyte membrane according to claim 1 or 2, characterized in that: in the two-layer electrolyte membrane, any one layer of the electrolyte membrane is dense to achieve the purpose of gas barrier. 5. The anode-loaded double-layer electrolyte membrane as claimed in claim 1 or 2, characterized in that: the anode is made of metal composite ceramics, wherein the metal catalyst includes Ni, Co, Cu, Rh, Fe, Pt, Pd , Mo, Ti; metal composite ceramics, oxide ceramics include Y ₂ O ₃ stabilized ZrO ₂ (YSZ), Gd ₂ O ₃ doped CeO ₂ (GDC), La ₂ O ₃ doped CeO ₂ (LDC ), Sm ₂ O ₃ doped CeO ₂ (SDC), Sc ₂ O ₃ stabilized ZrO ₂ (ScSZ). 6. The anode-loaded double-layer electrolyte membrane as claimed in claim 2, characterized in that: said cathode is made of La _x Sr _1-x CoO 3 , Sm _x Sr 1-x CoO ₃ , La x Sr _1-x CoO ₃ , La _x Sr _{1-x x} MnO ₃ , La _x Ni _1-x FeO ₃ . 7. A method for preparing an anode-loaded double-layer electrolyte membrane as claimed in claim 1, characterized in that: comprising the following steps: a) Prepare the anode substrate, _CeO barrier reaction (LDC) layer and electron conductance barrier (LSGM) layer by common techniques for the next step; b) one side of the _CeO barrier reaction (LDC) layer is affixed to one side of the anode substrate by conventional techniques; c) with the usual technique, one side of the electron conductance barrier (LSGM) layer is affixed to the CeO on the _other side of the barrier reaction (LDC) layer; d) After co-sintering and densifying the semi-finished product obtained in step c) at high temperature, an anode electrolyte two-in-one component is obtained; e) The cathode is fixedly connected to the other side of the electronic conductance barrier (LSGM) layer by common techniques, and after sintering at an appropriate temperature, a membrane-electrode three-in-one component is obtained. 8. The preparation method as claimed in claim 7, characterized in that: the commonly used techniques in the steps of a), b) and c) are traditional anolyte two-in-one preparation techniques, such as dry pressing, screen printing, Any one of a group of processes such as coating, casting, film rolling, and film scraping. 9. preparation method as claimed in claim 7, it is characterized in that: common technology in the described e) step is traditional negative electrode preparation technology, is screen printing, coating, sputtering, plasma spraying, electrochemical deposition, Any of a group of chemical deposition processes.

Images