CN101304093A - A low-temperature solid oxide fuel cell three-in-one component MEA and its preparation - Google Patents

Abstract

A low-temperature solid oxide fuel cell three-in-one component MEA and its preparation include an anode substrate, an electrolyte membrane layer and a cathode, and a perovskite composite oxide transition layer is arranged between the electrolyte membrane layer and the cathode. The performance of the low-temperature solid oxide fuel cell prepared by the method can be increased by more than 30% compared with the cell with the same other conditions but no interlayer.

Description

A low-temperature solid oxide fuel cell three-in-one component MEA and its preparation

technical field

The invention relates to the field of solid oxide fuel cells, in particular to a high-performance low-temperature solid oxide fuel cell (working temperature 500-650°C) three-in-one component MEA with a perovskite composite oxide transition layer structure and its Preparation.

Background technique

Solid oxide fuel cell is an energy conversion device that directly converts chemical energy into electrical energy. It adopts an all-solid structure and has the characteristics of high power generation efficiency and wide application range. It is an ideal technology for decentralized power generation and centralized power stations, and can also be used for vehicle auxiliary power supplies, portable power supplies, etc. In order to reduce manufacturing costs, improve reliability, and shorten start-up time, low-temperature solid oxide fuel cells that lower the operating temperature of solid oxide fuel cells to 500-650 °C have become the focus of research and development at home and abroad. However, currently used low-temperature cathode materials, such as Ba _x Sr _1-x Co _y Fe _1-y O ₃ (BSCF) (0<x<1, 0<y<1), Sm _x Sr _1-x CoO ₃ (SSC) (0<x<1), etc., have high sintering activity. At the usual cathode calcination temperature (1100-1200°C), it is very easy to sinter and become dense and reduce the porosity of the cathode, hindering the diffusion and transfer of oxygen and electrocatalysis. Reducing activity. Lowering the calcination temperature can maintain a certain porosity, but at the same time, it will cause the cathode and the electrolyte to be weakly bonded and easily peeled off; the interface resistance between the cathode and the electrolyte will increase. The low-temperature solid oxide fuel cell with an electrolyte thickness of 20 microns obtained by the current battery preparation technology has an ohmic resistance of 0.2Ω·cm ² -0.45Ω·cm ² , which is much higher than the theoretical value of the ohmic resistance of the electrolyte, so in a large It affects the output power of the battery to a certain extent. Under low-temperature operating conditions, the interface resistance between the electrolyte and the cathode has become one of the main factors affecting the performance of low-temperature solid oxide fuel cells.

Contents of the invention

In order to solve the problem of large interface resistance between the electrolyte and the cathode in the low-temperature solid oxide fuel cell, the object of the present invention is to provide a low-temperature solid oxide fuel cell with a perovskite composite oxide transition layer structure and its preparation method, by introducing a transition layer composed of a perovskite composite oxide material between the electrolyte and the cathode to promote the effective contact between the electrolyte and the cathode and reduce the interface resistance between the electrolyte/cathode, thereby effectively improving the The output power of the battery.

To achieve the above object, the technical scheme adopted in the present invention is:

A low-temperature solid oxide fuel cell (operating temperature 500-650°C) three-in-one assembly MEA, including an anode substrate, an electrolyte membrane layer and a cathode, and a perovskite-type composite oxide transition is provided between the electrolyte membrane layer and the cathode layer; that is, a transition layer composed of a perovskite composite oxide material is added on the side where the electrolyte membrane contacts the cathode, and the effective interaction between the electrolyte and the cathode is promoted by adjusting the material, thickness and firing temperature of the transition layer. Contact, reduce interface resistance.

The perovskite composite oxide is

(Ln _1-x A _x ) _1-y Mn _y O _3±δ , where Ln=La, Nd or Pr, A=Sr or Ca, 0<x<1, 0<y≤1, 0≤δ<1 ;

Ln _1-x Sr _x Fe _1-y Co _y O _3±δ , where Ln=La, Sm, Nd, Gd or Dy, 0<x<1, 0<y≤1, 0≤δ<1;

Ba _x Sr _1-x Co _y Fe _1-y O ₃ (BSCF), where 0<x<1, 0<y<1;

Or La _1-x Sr _x Ga _1-y Mg _y O _3±δ , wherein 0<x<1, 0<y<1, 0<δ<1.

The thickness of the transition layer is controlled between 20 nanometers and 5 micrometers, preferably 30 nanometers and 2 micrometers.

The material for making the anode can be a metal composite ceramic, wherein the metal catalyst is Ni, Co, Cu, Rh, Fe, Pt, Pd, Mo and/or Ti; the oxide is Sm _x Ce _1-x O ₂ (SDC) , Gd _x Ce _1-x O ₂ (GDC), Y _x Ce _1-x O ₂ (YDC), La _x Ce _1-x O ₂ (LDC), Y ₂ O ₃ stabilized ZrO ₂ (YSZ) and/or or Sc ₂ O ₃ stabilized ZrO ₂ (ScSZ), where 0<x<1; its thickness may be 300 μm-1 mm;

The electrolyte diaphragm layer is a CeO2-based electrolyte doped with rare earth oxides such as Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , and the doping amount in _{the CeO 2 base} is 5-50% by mole, Its synthesis method can adopt co-precipitation method, hydrothermal synthesis method, citric acid method, combustion method and glycine method; the diaphragm layer composed of perovskite composite oxide material can adopt dry pressing method, scraping method and screen printing method , coating method, casting method, vapor deposition method, plasma spraying method, magnetron sputtering and other methods, and its thickness is 10-60 microns;

The cathode can be composed of a pure cathode material or a composite cathode composed of a cathode material and an electrolyte, wherein the weight percentage of the cathode material is >50%; the cathode material is Ba _x Sr _1-x Co _y Fe _1-y O ₃ (BSCF) or Sm _x Sr _1-x CoO ₃ (SSC), where 0<x<1, 0<y<1, and its thickness may be 10-70 microns.

Preparation of three-in-one component MEA: the anode substrate, electrolyte diaphragm layer and cathode of the MEA can be prepared by conventional inorganic membrane preparation methods, and the perovskite type composite can be introduced between the electrolyte diaphragm layer and cathode by conventional inorganic membrane preparation methods Oxide transition layer, perovskite-type composite oxide transition layer can be dense or porous, but its preparation temperature is lower than that of the dense electrolyte diaphragm layer, generally 100-500°C lower, perovskite-type composite oxide The sintering temperature of the material transition layer is 1000-1400 °C; the conventional inorganic film preparation method is dry pressing method, scraping film method, screen printing method, coating method, casting method, vapor deposition method, plasma spraying or magnetic controlled sputtering method.

Specifically, such as: preparing anode/electrolyte components by common techniques; uniformly mixing perovskite composite oxide transition layer materials with a particle size of 2 nanometers to 0.1 micrometers It is prepared on the side where the electrolyte and the cathode are in contact by screen printing or coating, or the perovskite composite oxide transition layer material is prepared on the electrolyte by methods such as vapor deposition, plasma spraying, and magnetron sputtering. The side that is in contact with the cathode. The thickness of the transition layer is controlled between 20 nanometers and 5 microns, the sintering temperature is controlled at 1000-1400°C, and then the cathode is prepared on the transition layer. The performance of the low-temperature solid oxide fuel cell prepared by the method can be increased by more than 30% compared with the cell with the same other conditions but no interlayer.

The excellent effect of the present invention is:

The surface structure of the electrolyte separator is improved by introducing a transition layer composed of a perovskite composite oxide material between the low-temperature electrolyte and the low-temperature cathode. The transition layer is tightly combined with the electrolyte and embedded in the cathode, which can promote The contact of the electrolyte with the cathode.

1. The preparation process of the low-temperature solid oxide fuel cell of the present invention is simple, and various membrane-making technologies can be used. Such as: dry pressing method, scraping film method, screen printing method, coating method, casting method, vapor deposition method, plasma spraying or magnetron sputtering method.

2. The solid oxide fuel cell prepared by the invention can effectively reduce the interface resistance of the cell under low-temperature operating conditions and improve cell efficiency. The present invention introduces a perovskite-type composite oxide functional transition layer between the electrolyte and the cathode, and promotes the effective contact between the electrolyte and the cathode through secondary baking of the functional layer, reduces the interface resistance between the electrolyte/cathode, and improves The contact strength between the electrolyte/cathode can effectively improve the output power of the battery.

3. The present invention can be used in various configurations of solid oxide fuel cells such as flat plate and tube. The three-in-one component MEA can be used in solid oxide fuel cells of flat plate type, tube type and other various configurations.

4. The present invention is applicable to various application fields of low-temperature solid oxide fuel cells, such as portable power sources, decentralized power sources, and the like.

Description of drawings

Accompanying drawing 1 is the schematic structural diagram of the anode-supported low-temperature solid oxide fuel cell with a perovskite-type composite oxide transition layer.

Detailed ways

Example 1

Flat Low Temperature Solid Oxide Fuel Cell with LSM as Transition Layer

As shown in Figure 1, it is a schematic structural diagram of an anode-supported low-temperature solid oxide fuel cell with a perovskite-type composite oxide transition layer, including an anode substrate 1, a cerium-based electrolyte diaphragm layer 2, and a perovskite-type composite oxide transition layer. layer 3 and cathode 4. The NiO-GDC/GDC two-in-one was prepared by dry pressing, in which the GDC electrolyte was synthesized by the glycine method, and the two-in-one was co-fired at 1420°C for 4 hours to obtain the anode/electrolyte assembly. Prepare an LSM transition layer with a thickness of 500 nanometers on the GDC electrolyte side by casting method, dry it in the air, and bake it at a temperature lower than 120°C for 2 hours to obtain a porous LSM transition layer.

The BSCF-GDC composite cathode was prepared by coating method, in which the BSCF content was 70%, and baked at 950°C for 2 hours.

Using hydrogen as fuel gas and air as oxidant, test battery performance at 500-600°C. At 500°C, the maximum power density reaches 0.392W·cm ^-2 , which is 37.6% higher than that of the battery with the same conditions but without a transition layer; the ohmic resistance is 0.276Ω·cm ^-2 , which is higher than that of the battery with the same conditions but without a transition layer 33% lower battery.

Example 2

Flat Low Temperature Solid Oxide Fuel Cell Using LSGM as Transition Layer

The NiO-SDC/SDC two-in-one was prepared by casting method, in which the SDC electrolyte was synthesized by citric acid method, and the two-in-one was co-fired at 1450 °C for 4 hours to obtain the anode/electrolyte assembly. Prepare a LSGM transition layer with a thickness of 0.75 microns on the side of the SDC electrolyte by casting method, dry it in the air, and bake it at a temperature lower than 200°C for 2 hours to obtain a porous LSGM transition layer.

The BSCF-SDC composite cathode was prepared by screen printing method, in which the BSCF content was 70%, and baked at 950°C for 2 hours.

Using hydrogen as fuel gas and oxygen as oxidant, test battery performance at 500-600°C. At 600°C, the maximum power density reaches 0.91W·cm ^-2 , which is 58.5% higher than that of the battery with the same conditions but no transition layer.

Example 3

Flat Low Temperature Solid Oxide Fuel Cell Using LSCF as Transition Layer

The flat-plate NiO-GDC/GDC two-in-one was prepared by rolling film method and baked at 1500 ° C. The LSCF transition layer with a thickness of 500 nm was prepared on the electrolyte side by spraying method. The GDC and LSCF materials were prepared by citric acid method. Baking the electrolyte at a temperature of 200° C. for 1 hour to obtain a dense anode/electrolyte assembly with both the electrolyte and the transition layer.

The BSCF-GDC composite cathode was prepared by screen printing method, in which the BSCF content was 70%, and it was baked at 1000°C for 2 hours.

Using hydrogen as fuel gas and air as oxidant, test battery performance at 500-600°C. The maximum power density reaches 0.3W·cm ^-2 at 500°C, which is 31.2% higher than that of the battery with the same conditions but no transition layer.

Example 4

Flat Low Temperature Solid Oxide Fuel Cell Using LSC as Transition Layer

A flat NiO-YDC anode was obtained by pressing under a certain pressure, and a YDC electrolyte layer was prepared on its surface by a tape casting method, and co-fired at 1450°C for 4 hours, wherein YDC was synthesized by a co-precipitation method. The LSC transition layer prepared by sputtering on one side of the fired YDC has a thickness of 1 micron.

The BSCF cathode was prepared by coating method, in which the BSCF content was 100%, and it was baked at 1000°C for 2 hours.

Using hydrogen as fuel gas and air as oxidant, test battery performance at 500-600°C. The maximum power density reaches 0.95W·cm ^-2 at 600°C, which is 41.6% higher than that of the battery with the same conditions but no transition layer.

Example 5

Tubular low temperature solid oxide fuel cell with BSCF as transition layer

The NiO-GDC tubular anode was prepared by extrusion molding, and a layer of GDC electrolyte layer was loaded on the anode by spraying method, and the anode-loaded electrolyte film NiO-GDC/GDC was prepared by co-sintering at 1450 ° C. The thickness of the electrolyte film was 20 microns. Then, a layer of BSCF was sputtered on the surface of the GDC electrolyte separator at room temperature with a thickness of 200 nm.

The SSC cathode was prepared by screen printing method, in which the SSC content was 100%, and baked at 1000°C for 2 hours.

Using hydrogen as fuel gas and air as oxidant, test battery performance at 500-600°C. The maximum power density reaches 0.5W·cm ^-2 at 600°C, which is 30.6% higher than that of the battery with the same conditions but no transition layer.

Claims (8)

1. A low-temperature solid oxide fuel cell three-in-one component MEA, comprising an anode substrate (1), an electrolyte membrane layer (2) and a cathode (4), is characterized in that: between the electrolyte membrane layer (2) and the cathode A perovskite composite oxide transition layer (3) is provided. 2. According to the three-in-one component MEA according to claim 1, it is characterized in that: the perovskite type composite oxide is (Ln _1-x A _x ) _1-y Mn _y O _3±δ , where Ln=La, Nd or Pr, A=Sr or Ca, 0<x<1, 0<y≤1, 0≤δ<1 ; Ln _1-x Sr _x Fe _1-y Co _y O _3±δ , where Ln=La, Sm, Nd, Gd or Dy, 0<x<1, 0<y≤1, 0≤δ<1; Ba _x Sr _1-x Co _y Fe _1-y O ₃ , wherein 0<x<1, 0<y<1; Or La _1-x Sr _x Ga _1-y Mg _y O _3±δ , wherein 0<x<1, 0<y<1, 0<δ<1. 3. The three-in-one component MEA according to claim 1, characterized in that: the thickness of the transition layer (3) is controlled between 20 nanometers and 5 micrometers. 4. The three-in-one component MEA according to claim 1, characterized in that: the optimal thickness of the transition layer (3) is controlled between 30 nanometers and 2 micrometers. 5. According to the three-in-one component MEA according to claim 1, it is characterized in that: the preparation material of the anode is a metal composite ceramic, and the metal catalyst is Ni, Co, Cu, Rh, Fe, Pt, Pd, Mo and/or Or Ti; oxides are Sm _x Ce _1-x O ₂ , Gd _x Ce _1-x O ₂ , Y _x Ce _1-x O ₂ , La _x Ce _1-x O ₂ , Y ₂ O ₃ stabilized ZrO ₂ and/or Sc ₂ O ₃ stabilized ZrO ₂ , where 0<x<1; its thickness may be 200 microns to 5 mm; The electrolyte diaphragm layer is _CeO2- based electrolyte doped with rare earth oxides, with a thickness of 10-100 microns; The cathode can be composed of pure cathode material or a composite cathode composed of cathode material and electrolyte, wherein the weight percentage of the cathode material is >50%; the cathode material is Ba _x Sr _1-x Co _y Fe _1-y O ₃ or Sm _x Sr _1-x CoO ₃ , where 0<x<1, 0<y<1, and its thickness can be 10-70 microns. 6. According to the three-in-one component MEA according to claim 5, it is characterized in that: the rare earth oxide is Sm ₂ O ₃ , Gd ₂ O ₃ or Y ₂ O ₃ , and its doping amount in the CeO ₂ base is The molar percentage is 5-50%. 7. A method for preparing the three-in-one component MEA according to claim 1, characterized in that: the anode substrate, the electrolyte diaphragm layer and the negative electrode of the MEA can be prepared by a conventional inorganic membrane preparation method, and the conventional inorganic membrane preparation method is adopted simultaneously A perovskite-type composite oxide transition layer is introduced between the electrolyte diaphragm layer and the cathode. The perovskite-type composite oxide transition layer can be dense or porous, but its preparation temperature is lower than that of a dense electrolyte diaphragm layer , generally lower than 100-500°C, and the sintering temperature of the perovskite composite oxide transition layer is 1000-1400°C. 8. According to the preparation method of the three-in-one component MEA according to claim 7, it is characterized in that: the conventional inorganic film preparation method is dry pressing method, scraping film method, screen printing method, coating method, casting method , vapor deposition, plasma spraying or magnetron sputtering.