CN103474687A - Method for preparing a high-performance slab solid oxide fuel single battery - Google Patents

Abstract

The invention relates to a method for preparing a high-performance flat solid oxide fuel single cell. The preparation method comprises: superimposing a support electrode membrane and an electrolyte membrane and then hot pressing under vacuum conditions to form a first composite membrane; After the supporting electrode diaphragm and the replica diaphragm are stacked, the second composite diaphragm is formed by hot pressing; after the electrolyte side of the first composite diaphragm is in contact with the non-supporting electrode side of the second composite diaphragm, heat pressing to form a single cell green; and sintering the single cell green to form a single cell, during which the replica membrane is burned out; wherein the supporting electrode membrane forms an anode membrane And the unsupported electrode membrane forms a cathode membrane, or the supporting electrode membrane forms a cathode membrane and the unsupported electrode membrane forms an anode membrane; Composition of matter that can burn out in time.

Description

A preparation method of a high-performance flat solid oxide fuel cell

technical field

The invention relates to a preparation method of a high-performance flat solid oxide fuel cell, and belongs to the field of energy materials.

Background technique

Solid oxide fuel cell (Solid oxide fuel cell, SOFC) is a device that can directly convert fuel chemical energy into electrical energy. Hydrogen, natural gas, synthetic gas, liquid hydrocarbon fuel), no need for precious metal catalysts, safety and pollution-free, etc., have broad application prospects in large power plants, distributed power sources and household combined heat and power.

SOFC can be classified into high temperature (800-1000°C), medium-high temperature (600-800) and low temperature (<600°C) SOFC according to its working temperature. At present, the operating temperature of the mainstream SOFC is generally between 700-800 ° C, which belongs to the medium and high temperature category. High-temperature operation not only increases the material cost of SOFCs, but also brings stability issues, which seriously hinders their practical applications. Reducing the operating temperature of SOFC and replacing expensive ceramics with cheap stainless steel can effectively reduce the material cost of SOFC stacks. In addition, lowering the temperature can also reduce the thermal stress between multilayer ceramics and slow down the wear and tear of electrode materials. Aging rate, improve the long-term stability of the stack output power. Therefore, low temperature SOFC is the current research trend in the world.

An important index to evaluate the performance of SOFC single cell is impedance. In SOFC, impedance includes ohmic impedance (Zohm), polarization impedance and interface contact impedance (Zinterface), where polarization impedance is further divided into anode polarization impedance (Zanode) and cathode polarization impedance (Zcathode). As the operating temperature of SOFC decreases, the ohmic impedance, polarization impedance, and interfacial contact impedance all increase significantly, resulting in a sharp decline in battery performance. To some extent, the study of low-temperature SOFC is the study of reducing impedance.

The reduction of ohmic impedance can be satisfied by thinning the electrolyte thickness or adopting new electrolyte materials. As far as the current anode support or cathode support structure is concerned, the thickness of the electrolyte has been reduced from the traditional hundreds of microns to 5-15 μm, and the ohmic impedance has been greatly reduced. New electrolyte materials, such as strontium- and magnesium-doped lanthanum gallate (LSGM), and samarium- or gadolinium-doped ceria (ie, SDC or GDC), have demonstrated sufficient electrical conductivity at low temperatures. The total ohmic resistance of the above-mentioned novel electrolyte with a thickness of 10 μm is only 0.1Ω·cm ² at 550°C. Generally speaking, for SOFCs operating at 550-600 °C, ohmic impedance is not a key factor restricting its performance.

It can be seen that the electrode polarization resistance and interface contact resistance of the battery are the main factors that limit its performance. Screen printing and solution impregnation are currently the two main methods for preparing electrodes. Compared with the screen printing method, the electrode active components obtained by the solution impregnation method are in a nano-dispersion state, and its performance is often an order of magnitude higher. It is currently the mainstream electrode preparation method for low-temperature SOFC. Taking the impregnated anode as an example, the preparation method of the Ni/SDC impregnated composite anode is as follows: impregnate the nickel nitrate complex solution into the porous electrolyte skeleton through capillary force, dry at 85°C for 30min, and calcinate at 700-850°C for 2h-10h to form an impregnated composite anode. Because Ni has excellent catalytic performance for H2, Ni composite anodes often have very low polarization resistance. The polarization resistance of the Ni/LSGM impregnated anode reported by LIU et al. at 550°C is only 0.01Ω·cm ² , which is completely negligible. The impregnated cathode is similar to the impregnated anode, the difference is that instead of Ni, the cathode active material includes La _0.5 Sr _0.5 CoO ₃ , La _0.6 Sr _0.4 Co _0.8 Fe _0.2 O ₃ , La _0.6 Sr _0.4 FeO ₃ , Ba _0.5 Sr _0.5 Co Perovskite structures such _{as 0.8} Fe _0.2 O ₃ and Sm _0.5 Sr _0.5 CoO ₃ and double perovskite and layered perovskite structures such as GaBaCo ₂ O ₅ , SmBaCo ₂ O ₅ , PrBaCo ₂ O ₅ and La ₂ NiO ₄ Material. Xia et al. impregnated SSC nanoparticles in the SDC framework, and its polarization impedance at 550°C was 0.1Ω·cm ² . Zhan et al. impregnated the SSC/SDC mixed solution in the LSGM framework, and the polarization impedance at 550°C was only is 0.075Ω·cm ² , and Han et al. impregnated SBSCO in the LSGM framework to form a composite cathode, and the polarization resistance was even as low as 0.035Ω·cm ² at 550°C.

If the interface contact resistance is not considered, only the ohmic resistance and polarization resistance are considered, and the power density at 550°C can theoretically reach 1.5W/cm ² with 10 micron thick SDC (GDC) or LSGM as the electrolyte. But in practice, this performance is difficult to achieve. It can be seen that the total impedance of low-temperature SOFC also includes a certain amount of interfacial contact impedance. As the name implies, the interfacial contact resistance is related to the bonding degree of the interface, so its size has a lot to do with the preparation process of the battery. At present, there are three main methods for the preparation of SOFC single cells: the traditional two-step sintering method, that is, first pre-burning a half-cell composed of an electrode and an electrolyte, and then screen-printing another half-cell on the pre-fired electrolyte. A single electrode component, after secondary sintering, a single cell or a single cell skeleton can be obtained. Compared with co-sintering, the interfacial contact resistance after secondary sintering is often also very large, especially at low temperatures; the second preparation method is screen printing, that is, screen printing on the "electrode/electrolyte" composite green body Print another electrode material, and finally co-sinter together to obtain a single cell or a single cell skeleton. Researchers such as Shanghai Jiaotong University in China and the University of Pennsylvania in the world initially used this method to prepare single cells. This method can be used to a certain extent. To reduce the interface contact resistance, but the process is more complex, while the yield is very low. The third preparation method is the film pasting method, which refers to pasting another electrode casting film on the "supporting electrode/electrolyte" composite body. Although this pasting method can prepare a single cell and has a high yield, it does not The reliability of the interface contact cannot be guaranteed, the difference between different batteries is also very large, and the performance of the battery is also far from the theoretical value.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a method for preparing a single high-performance solid oxide fuel cell, so as to eliminate or reduce the interface resistance between the electrode and the electrolyte, and prepare a SOFC single cell with excellent performance.

Here, the present invention provides a method for preparing a high-performance flat solid oxide fuel cell, comprising: forming a first composite membrane by hot pressing under vacuum conditions after stacking a supporting electrode membrane and an electrolyte membrane; The electrode diaphragm and the replica diaphragm are stacked and hot-pressed to form a second composite diaphragm; the electrolyte side of the first composite diaphragm is in contact with the non-supporting electrode side of the second composite diaphragm and then hot-pressed forming a single cell green; and sintering the single cell green to form a single cell, during which the replica membrane is burned out; wherein the supporting electrode membrane forms an anode membrane and The unsupported electrode membrane forms a cathode membrane, or the supporting electrode membrane forms a cathode membrane and the unsupported electrode membrane forms an anode membrane; Composition of substances capable of burning out.

The invention adopts composite membrane technology, which can realize the co-pressing and co-sintering of the three parts of "anode, electrolyte and cathode", thereby effectively eliminating or reducing the interface contact resistance between the electrode and the electrolyte, and the unsupported electrode membrane and the complex The laminated diaphragms are stacked and hot-pressed to form a composite diaphragm, which can prevent the failure of the electrolyte diaphragm caused by the electrolyte being pressed into the electrode during hot pressing. In addition, the replica membrane is burned out during the sintering process, so it does not affect the single cell. Compared with the traditional secondary sintering method, screen printing method and film pasting method to prepare electrodes, the invention has the advantages of simple process, high yield, good repeatability and excellent performance. Moreover, compared with the traditional secondary sintering method, the energy consumption of the primary sintering is halved, the preparation time is halved, and the cost is significantly reduced. Therefore, the present invention is suitable for preparing small batteries or large batteries, especially suitable for preparing large-area single batteries, and can be used for large-scale production.

Preferably, the supported electrode membrane, electrolyte membrane, unsupported electrode membrane, and/or replica membrane can be prepared by casting method.

Preferably, the flat plate area of the supporting electrode film may be larger than the flat plate area of the non-supporting electrode film. In this way, an electrolyte space can be reserved between the anode and the cathode to isolate the anode and the cathode, so as to facilitate the later packaging of the battery.

Preferably, the thickness ratio of the unsupported electrode membrane to the replica membrane may be (1-3):10.

Preferably, the supporting electrode membrane and/or the non-supporting electrode membrane may be a porous electrolyte skeleton composed of an electrolyte material, a porous electrode skeleton composed of an electrode active material, and a composite of an electrolyte material and an electrode active material. Any one of the porous composite electrode skeletons formed.

Preferably, the electrolyte material can be strontium-magnesium co-doped lanthanum gallate, doped bismuth oxide or other bismuth-based oxides, yttrium-stabilized zirconia, scandium-stabilized zirconia, doped cerium oxide, silicon ( lanthanum germanate), perovskite structure (Ba2In2O5) or its doped oxides, and/or barium cerate.

Preferably, the substance capable of burning out at 200-1450°C may be graphite, carbon powder, starch or any other organic powder.

Preferably, the supporting electrode membrane may have a thickness of 100 μm-400 μm, and a porosity of 30%-80%, preferably 40%.

Preferably, the thickness of the unsupported electrode membrane may be 5 μm-100 μm, and the porosity may be 30%-80%, preferably 40%.

Preferably, the hot pressing may be performed at 50-90° C. for 5-25 minutes under a pressure of 1000-5000 PSI.

Preferably, the sintering may be performed at 1200-1500° C. for 2-24 hours.

Preferably, the supporting electrode membrane, the non-supporting electrode membrane, and/or the replica membrane may be a structure in which more than one layer of respective single-layer blanks are stacked. By adjusting the number of layers of superimposed single-layer blanks, the thickness of each diaphragm can be effectively controlled, and the product yield can be improved.

Description of drawings

Fig. 1 is a schematic diagram of the preparation process of a high-performance flat SOFC single cell according to an embodiment of the present invention;

2 is a SEM microstructure diagram of a single battery according to Embodiment 1 of the present invention;

3 is an electrochemical impedance spectrum diagram of a single cell according to Example 1 of the present invention;

Fig. 4 is the electrochemical performance diagram of the single cell according to embodiment 1 of the present invention;

Fig. 5 is a comparison chart of the electrochemical performance of the single cell according to Example 1 of the present invention and the single cell obtained by the film sticking method;

Fig. 6 is the graph of the electrochemical performance of the single cell according to embodiment 2 of the present invention;

FIG. 7 is a diagram of the electrochemical performance of a single cell according to Example 3 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the drawings and the following embodiments. It should be understood that the following drawings and/or embodiments are only used to illustrate the present invention rather than limit the present invention.

The present invention adopts the composite membrane technology, aiming at realizing the green body co-pressing and co-sintering of "anode/electrolyte/cathode" single cells.

Fig. 1 shows a schematic diagram of the preparation process of a high-performance flat SOFC single cell according to an embodiment of the present invention. Referring to Fig. 1, the preparation method of the present invention is illustrated.

First, an electrolyte membrane, a supported electrode (anode or cathode) membrane, an unsupported electrode (cathode or anode) membrane, and a replica membrane are cast, respectively.

The electrolyte membrane can be made by ball milling and mixing electrolyte materials, dispersants, binders, plasticizers and solvents, and then casting. However, it should be understood that the casting method of the electrolyte membrane is not limited thereto, and any casting method that can obtain a dense electrolyte membrane is included in the present invention. The electrolyte materials include, but are not limited to, strontium-magnesium co-doped lanthanum gallate (LSGM), doped bismuth oxide or other bismuth-based oxides, yttrium-stabilized zirconia (YSZ), scandium-stabilized zirconia (SSZ) , doped cerium oxide, silicon (lanthanum germanate), perovskite structure (Ba2In2O5) or its doped oxide, and/or barium cerate.

The supported electrode membrane and/or the unsupported electrode membrane can be a porous electrolyte skeleton that is only cast after mixing electrolyte materials, pore-forming agents, dispersants, binders, plasticizers and solvents; it can also be A porous electrode skeleton casted after mixing electrode active materials (anode active materials or cathode active materials), pore-forming agents, dispersants, binders, plasticizers and solvents; it can also be made of electrode active materials ( Anode active materials or cathode active materials), electrolyte materials, pore formers, dispersants, binders, plasticizers and solvent ball milling mixed porous composite electrode skeleton. It should also be understood that the casting method of the supporting electrode film and/or the non-supporting electrode film is not limited thereto, as long as the casting method of the porous supporting electrode film and/or the porous non-supporting electrode film is included in this inventing. The electrolyte materials include, but are not limited to, strontium-magnesium co-doped lanthanum gallate (LSGM), doped bismuth oxide or other bismuth-based oxides, yttrium-stabilized zirconia (YSZ), scandium-stabilized zirconia (SSZ) , doped cerium oxide, silicon (lanthanum germanate), perovskite structure (Ba2In2O5) or its doped oxide, and/or barium cerate. The anode active material includes but not limited to NiO, the cathode active material includes but not limited to La _0.8 Sr _0.2 MnO ₃ , La _0.5 Sr _0.5 CoO ₃ , La _0.6 Sr _0.4 Co _0.8 Fe _0.2 O ₃ , La _0.6 Sr _0.4 FeO ₃ , Ba _0.5 Sr _0.5 Co _0.8 Fe _0.2 O ₃ and Sm _0.5 Sr _0.5 CoO ₃ , La _0.9 Sr _0.1 NiO manganate, cobaltate, ferrite and nickelate and other perovskite structures and GaBaCo ₂ O ₅ , SmBaCo ₂ O ₅ , PrBaCo ₂ O ₅ and La ₂ NiO ₄ and other double perovskite and layered perovskite structure materials.

In addition, the thickness of the supported electrode film and/or the unsupported electrode film can be adjusted by the height of the casting knife and the viscosity of the slurry. The thickness range of the supporting electrode membrane is adjustable between 100 μm and 400 μm, and the thickness range of the non-supporting electrode membrane is adjustable between 5 μm and 100 μm. The porosity of the supported electrode membrane and/or the unsupported electrode membrane can be adjusted by the type and quantity of the pore-forming agent and the sintering shrinkage of the single cell, for example, it can be adjusted between 30% and 80%, preferably 40%.

The replica diaphragm can be made by mixing and casting materials that can burn out between 200 and 1450°C with certain additives. By means of this, the replica membrane can be retained during the hot pressing process described below, and can be burned out during the sintering process described below. The substances that can be burned at 200-1450°C include but are not limited to graphite, carbon powder or starch. It should also be understood that any casting method capable of obtaining a replica film is included in the present invention.

Then, as described below, the supporting electrode membrane and the electrolyte membrane were superimposed and hot-pressed under vacuum conditions to form the first composite membrane, and the unsupported electrode membrane and the replica membrane were superimposed and hot-pressed to form the second composite membrane. Diaphragm. Wherein, the supporting electrode membrane can form the anode membrane and the unsupported electrode membrane can form the cathode membrane, or the supporting electrode membrane can form the cathode membrane and the unsupported electrode membrane can form the anode membrane. Moreover, in the present invention, it may be that the flat plate area of the supporting electrode film is larger than the flat plate area of the non-supporting electrode film, thereby reserving an electrolyte space between the anode and the cathode to play the role of isolating the anode and the cathode, so as to It is convenient for the packaging of the battery in the later stage. Therefore, after the supported electrode membrane and the unsupported electrode membrane are prepared, they can be cut into large and small structures first, and then the following steps are performed.

First, as shown in the "first step" in Figure 1, according to the thickness requirements of the supporting electrode, stack multiple supporting electrode membranes and electrolyte membranes, and under vacuum conditions and hot pressing under pressure for 5-25 minutes to form the first composite membrane. The figure shows that four support electrode membranes are stacked, but this is only shown as an example. In the present invention, the number of stacked films is determined according to the thickness requirements of the support electrodes, for example, it can be 2 to 10 films. Through lamination hot pressing, the thickness of each layer can be effectively controlled and the product yield can be improved.

Next, as shown in the "second step" in Figure 1, the unsupported electrode diaphragm with a thickness ratio of (1-3): 10 is superimposed on the replica diaphragm at 50-90°C under a pressure of 1000-5000PSI The second composite membrane is formed under heat pressing for 5-25 minutes. By means of this, the unsupported electrode membranes are pressed into the replica membrane with their upper surfaces on the same plane. Among them, the replica diaphragm can be formed by superimposing and hot-pressing more than one replica diaphragm according to its thickness requirement. Similarly, the non-supporting electrode diaphragm can also be made by combining more than one non-supporting electrode The diaphragm is superimposed and hot-pressed. Through lamination hot pressing, the thickness of each layer can be effectively controlled and the product yield can be improved.

Next, as shown in the "third step" in Figure 1, the electrolyte side of the first composite membrane is superposed in contact with the non-supporting electrode side of the second composite membrane, and then heated at 50-90°C at 1000-5000PSI Hot pressing under pressure for 5 to 25 minutes to form a single cell blank. Then, the green body of the single cell is sintered at 1200-1500°C for 2-24 hours to make the single cell. During sintering, the replica membrane is burnt out to form anode (large side)/electrolyte/cathode (small side) or cathode (large side)/electrolyte/anode (small side) structures.

As shown in the "comparison step" in Figure 1, if the "anode/electrolyte/cathode" single-cell green body is directly co-pressed without using a replica film, the electrolyte will be pressed into the electrode, directly resulting in the diaphragm of the electrolyte The effect is invalid.

Therefore, compared with prior art, the present invention has following advantage:

(1) Compared with the traditional secondary sintering method, screen printing method and film pasting method to prepare electrodes, the preparation method of the present invention has the advantages of simple process, high yield, good repeatability and excellent performance;

(2) The present invention successfully realizes the co-pressing and co-sintering of the three components of "anode, electrolyte and cathode", effectively eliminating or reducing the interface contact resistance between the electrode and the electrolyte;

(3) The present invention is suitable for preparing small batteries or large batteries, especially suitable for preparing large-area single batteries, and can be used for large-scale production;

(4) Compared with the traditional secondary sintering method, the energy consumption of the primary sintering of the present invention is halved, the preparation time is halved, and the cost is significantly reduced;

(5) In the present invention, the thickness of each layer can be effectively controlled through lamination hot pressing, and the product yield is high.

The above is only a preparation process, but the above process is applicable to the preparation of different battery structures. That is, different battery structures can be formed according to the different configurations of the supporting electrode membrane and/or the unsupporting electrode membrane. Four battery structures are illustrated below, but it should be understood that they are only examples and not limited to these four structures.

Battery Structure I: "Porous Electrolyte/Dense Electrolyte/Porous Electrolyte" Structure

In this structure, the difference between the electrode formulation and the electrolyte formulation is that the electrode formulation additionally contains a certain amount of pore-forming agent. The electrolyte materials in the dense electrolyte and the porous electrolyte can be the same material or different materials. What is prepared by the above method is not a complete single cell, but only a single cell skeleton, and the complete single cell can be finally obtained by impregnating the active components of the anode and cathode on both sides.

Battery structure II: "anode (cathode) support/dense electrolyte/porous electrolyte" structure

In this structure, the difference between the electrode formulation and the electrolyte formulation is that the electrode formulation additionally contains a certain amount of pore-forming agent. The electrolyte materials in the dense electrolyte and the porous electrolyte can be the same material or different materials. The anode (cathode) support may be a simple anode (cathode) support, or a support with an active layer attached thereto. The only difference is that the composition of the cast film is different. What is prepared by the above method is not a complete single cell, but only a half cell. By impregnating the active components of the anode or cathode in the porous electrolyte to form the anode or cathode, a complete single cell can finally be obtained.

Battery structure III: "anode (cathode) support/dense electrolyte/porous cathode (anode)" structure

The porous cathode (anode) in this structure refers to the cathode material (anode material) that is distinct from the electrolyte material. The cathode material (anode material) may be a pure cathode material (anode material), or a composite electrode formed by combining a cathode (anode) and an electrolyte material. The anode (cathode) support may be a simple anode (cathode) support, or a support with an active layer attached thereto. The only difference is that the composition of the cast film is different. The prepared by the above method is not a complete single cell, but only a half cell. The cathode or anode can be formed by impregnating the electrolyte material in the porous cathode (anode), and finally a complete single cell can be obtained.

Battery structure IV: "anode (cathode) support/dense electrolyte/cathode (anode)" structure

The cathode (anode) in this structure refers to the cathode material (anode material) which is different from the electrolyte material. The cathode (anode) material may be a simple cathode (anode material), or a composite electrode composed of a cathode (anode) and an electrolyte material. The anode (cathode) support may be a simple support or a support with an active layer attached thereto. The cathode (anode) can be a single-layer structure, a double-layer structure with an active layer, or a multi-layer structure. The only difference is that the composition of the cast film is different.

Examples are given below to describe the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention, and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above contents of the present invention all belong to the present invention scope of protection. The specific parameters in the following examples are only examples of suitable ranges, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific values exemplified below.

Example 1

Battery Structure I: "Porous Electrolyte/Dense Electrolyte/Porous Electrolyte" Structure

Weigh an appropriate amount of commercial powder LSGM (lanthanum strontium gallium magnesium), use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, make a slurry suitable for casting, and cast to obtain the LSGM electrolyte body; weigh an appropriate amount of commercial Powder LSGM (lanthanum strontium gallium magnesium), pore-forming agent, alcohol and methyl ethyl ketone as solvent, add appropriate amount of additives, make slurry suitable for casting, cast LSGM porous electrode body; weigh appropriate amount of high-temperature combustible Non-toxic powder carbon powder, with alcohol and methyl ethyl ketone as solvent, adding appropriate amount of additives, made into a slurry suitable for casting, and casting to obtain a complex film body. The "porous electrolyte/dense electrolyte" support was obtained by superimposing three layers of porous electrode body and one layer of LSGM electrolyte body and hot pressing. A replica diaphragm with a certain thickness is obtained by superimposing two layers of replica diaphragms and hot pressing. A layer of porous electrolyte green body is superimposed on the above-mentioned replica membrane with a certain thickness, and hot-pressed to obtain a replica membrane loaded with electrodes. The support body and the electrode-loaded replica film are stacked and hot-pressed to obtain a complete single-cell blank. Put the single-cell blank into a high-temperature furnace and sinter at 1400° C. for 4 hours to obtain the single-cell skeleton. _{Ni (} NO ₃ ) ₃ is respectively impregnated on one side _of the single cell _skeleton , _and then heat-treated to obtain an anode _; The SBSCO cathode material composed of Ba(NO ₃ ) ₃ mixed solution, and then heat treated to obtain the cathode.

The microstructure diagram of the single cell obtained by the above preparation method is shown in Fig. 2 . Figure 3 is its electrochemical impedance spectrum. Figure 4 shows its electrochemical performance. Figure 5 compares the single cell performance obtained by the replica film technology with that obtained by the film sticking method. It can be seen from Figure 2 that the “porous LSGM/dense LSGM/porous LSGM” sandwich structure can be successfully obtained by the above-mentioned replica membrane technology, in which the thickness of the electrolyte is 8-9 μm, the supporting electrode is about 400 μm, and the thickness of the electrode on the other side is also about 40 μm. about. For LSGM, its conductivity at 550°C is generally 0.01S/cm, and the theoretical ohmic impedance of an 8-9μm electrolyte is 0.08-0.09Ωcm ² . It can be seen from Figure 3 that the ohmic impedance of the single cell obtained by the above-mentioned composite film technology is 0.1Ωcm ² at 550°C, which is basically equivalent to the theoretical ohmic impedance value, and the remaining 0.01-0.02Ωcm ² impedance value is completely is the interface contact impedance, and its value can also be ignored. It can be seen that by co-pressing and co-sintering the three components of "anode, electrolyte and cathode", the interface contact resistance between the electrode and the electrolyte is effectively eliminated. Figure 4 shows its power density diagram, and the performance of the single cell reaches 1.8W/cm ² at 550°C. Figure 5 compares the performance of the single cell obtained by the replica film technology and the film method, where A represents the replica film method, and B represents the film method. It can be seen from the figure that the single cell obtained by the replica film technology The performance of the battery is significantly higher than that of the single cell obtained by the film method.

Example 2

Battery structure II: "cathode support/dense electrolyte/anode" structure

Weigh an appropriate amount of commercial powder LSM (strontium-doped lanthanum manganate) and NiO, use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, and make a slurry suitable for casting, and cast to obtain LSM/NiO cathode support Electrode body; Weigh an appropriate amount of commercial powder 8YSZ (8% yttrium fully stabilized zirconia), use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, make a slurry suitable for casting, and cast to obtain 8YSZ electrolyte Green body; Weigh an appropriate amount of commercial powder 8YSZ (8% yttrium fully stabilized zirconia) and NiO, use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, make a slurry suitable for casting, and cast to obtain the anode Biscuit: Weigh an appropriate amount of high-temperature combustible powder carbon powder, use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, make a slurry suitable for casting, and cast to obtain a composite film blank. The "cathode support body/electrolyte" support body green body is obtained by superimposing three layers of support body electrode body and one layer of electrolyte body body and hot pressing. A replica diaphragm with a certain thickness is obtained by superimposing two layers of replica diaphragms and hot pressing. A layer of anode blank is superimposed on the above-mentioned replica film with a certain thickness, and after hot pressing, a replica diaphragm loaded with an anode is obtained. The support body and the replica film loaded with the anode are superimposed and hot pressed to obtain a complete single cell blank. The single cell blank is put into a high temperature furnace and sintered at 1250° C. for 4 hours to obtain a single cell. Fig. 6 is a graph of its electrochemical performance. It can be seen from the graph that the performance of the single cell reaches 0.63 W/cm ² at 850°C.

Example 3

Battery Structure III: "Anode Support/Dense Electrolyte/Porous Electrolyte" Structure

Weigh an appropriate amount of commercial powder 8YSZ (8% yttrium fully stabilized zirconia) and NiO, use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, and make a slurry suitable for casting, and the casting is supported by YSZ/NiO Body electrode green body; Weigh an appropriate amount of commercial powder 8YSZ (8% yttrium fully stabilized zirconia), use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, make a slurry suitable for casting, and cast to obtain 8YSZ Electrolyte body: Weigh an appropriate amount of commercial powder SSZ (10% scandium fully stabilized zirconia), pore-forming agent, use alcohol and methyl ethyl ketone as solvents, add appropriate amount of additives, and make a slurry suitable for casting. Stretching to obtain a porous electrolyte body; weighing an appropriate amount of high-temperature combustible powder carbon powder, using alcohol and methyl ethyl ketone as solvents, adding an appropriate amount of additives, making a slurry suitable for casting, and casting to obtain a composite membrane body. The "anode support/electrolyte" support body green is obtained by superimposing three layers of support body electrode green body and one layer of electrolyte green body and hot pressing. A replica diaphragm with a certain thickness is obtained by superimposing two layers of replica diaphragms and hot pressing. A layer of porous electrolyte green body is superimposed on the above-mentioned replica membrane with a certain thickness, and after hot pressing, a replica membrane loaded with porous electrolyte material is obtained. The support body is superimposed on the composite membrane loaded with the porous electrolytic material and hot pressed to obtain a complete single cell blank. The single-cell blank is put into a high-temperature furnace and sintered at 1400° C. for 4 hours to obtain a half-cell. The Sm _0.5 Sr _0.5 CoO ₃ cathode active material is impregnated in the porous electrolyte framework of the half-cell, and a complete single cell is obtained after heat treatment. Fig. 7 is a graph of its electrochemical performance. It can be seen from the graph that the performance of the single cell reaches 1.1 W/cm ² at 850°C.

Industrial Applicability: The present invention can effectively eliminate or reduce the interfacial contact resistance between electrodes and electrolytes, and prepare SOFC cells with excellent performance, and the method of the present invention has the advantages of simple process, strong operability, high yield and scalability Production and other advantages can be applied to the field of preparation of low-temperature SOFC.

Claims (12)

1. the preparation method of a high-performance flat-plate solid-oxide individual fuel cell, is characterized in that, comprising:

By after the stack of support electrode diaphragm and electrolyte membrane under vacuum condition hot pressing form the first compound film sheet;

Non-support electrode diaphragm is become to the second compound film sheet with hot pressing after the composite membrane stack;

After the non-support electrode of the electrolyte of described the first compound film sheet one side and described the second compound film sheet is simultaneously superposeed in contact, hot pressing becomes the monocell biscuit; And

By described monocell biscuit sintering to make monocell, at composite membrane described in described sintering process by after-flame;

Wherein, described support electrode diaphragm forms the anode diaphragm and described non-support electrode diaphragm forms the negative electrode diaphragm, or described support electrode diaphragm forms the negative electrode diaphragm and described non-support electrode diaphragm forms the anode diaphragm;

Described composite membrane is comprised of material that can after-flame between 200～1450 ℃.

2. preparation method according to claim 1, is characterized in that, described support electrode diaphragm, electrolyte membrane, non-support electrode diaphragm and/or composite membrane adopt the tape casting preparation.

3. preparation method according to claim 1 and 2, is characterized in that, the platen area of described support electrode diaphragm is larger than the platen area of described non-support electrode diaphragm.

4. according to the described preparation method of any one in claims 1 to 3, it is characterized in that, the Thickness Ratio of described non-support electrode diaphragm and described composite membrane is (1～3): 10.

5. according to the described preparation method of any one in claim 1 to 4, it is characterized in that, described support electrode diaphragm and/or described non-support electrode diaphragm are any one in the porous electrolyte skeleton consisted of electrolyte, the porous electrode skeleton consisted of electrode active material and the porous composite electrode skeleton that is composited by electrolyte and electrode active material.

6. preparation method according to claim 5, it is characterized in that the lanthanum gallate that described electrolyte is strontium magnesium codope, stable stable zirconia, doping bismuth oxide or other bismuth system oxide, doped cerium oxide, silicon (lanthanum germanate), calcium hematite structure (Ba2In2O5) or its doping oxide and/or the cerium acid barium of zirconia, scandium of yttrium.

7. preparation method according to claim 1, is characterized in that, described material that can after-flame between 200～1450 ℃ comprises graphite, carbon dust, starch or other any organic powder.

8. according to the described preparation method of any one in claim 1 to 7, it is characterized in that, the thickness of described support electrode diaphragm is 100 μ m～400 μ m, and porosity is 30%～80%.

9. according to the described preparation method of any one in claim 1 to 8, it is characterized in that, the thickness of described non-support electrode diaphragm is 5 μ m～100 μ m, and porosity is 30%～80%.

10. according to the described preparation method of any one in claim 1 to 9, it is characterized in that, described hot pressing is hot pressing 5～25 minutes under 50～90 ℃ of pressure at 1000～5000PSI.

11. according to the described preparation method of any one in claim 1 to 10, it is characterized in that, described sintering is 1200～1500 ℃ of sintering 2～24 hours.

12. according to the described preparation method of any one in claim 1 to 11, it is characterized in that, described support electrode diaphragm, non-support electrode diaphragm and/or composite membrane are the structures by the individual layer base substrate stack separately more than one deck.

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