CN1913208B - A kind of intermediate temperature solid oxide fuel cell system material and its battery and preparation method - Google Patents

Abstract

This invention relates to a mid-temperature solid oxide fuel battery system material, its battery and its preparation method taking LaCrO3, LaFeO3 and LaFeO3 base materials as the electrolyte of battery system materials, anode and cathode materials and preparing them first by a solid phase or humid chemical method then preparing the battery based on the kind of the supporting structure, and the system has fine comprehensive performance under low and mid temperatures (below 850deg.C), and can be operated in mid temperature; the electrolyte and the electrode materials has good chemistry and heat compatibility, and the battery performance is reduced; the anode materials has good anti-carbon performance, the polarization loss of the cathode is small, the fail-soft operation to the sulfur-containing and nitrogenous fuels is good, and the range of choice to fuel is large, and so on.

Description

A kind of intermediate temperature solid oxide fuel cell system material and its battery and preparation method

Technical field: The present invention relates to a medium-temperature solid oxide fuel system material, battery and preparation method thereof, belonging to the technical field of energy materials.

Technical Background: Solid Oxide Fuel Cell (SOFC) is regarded as one of the important technologies to solve energy problems in the 21st century because of its high efficiency and environmental friendliness. Most of the existing SOFC system materials use YSZ (yttria stabilized zirconia) as the electrolyte material. This material can only show good ion conductivity at a very high working temperature (about 1000 ° C); traditional anode materials ( For example, Ni-electrolyte) has serious carbon deposition, which causes rapid deterioration of battery performance; common cathode materials La _1-x Sr _x MnO ₃ show low electronic conductivity at medium and low temperatures (below 850°C), and the polarization effect is very strong. big.

The above-mentioned high operating temperature of the battery and the phenomenon of carbon deposition on the anode are the two main problems that plague the development of existing SOFCs. Excessive temperature will cause many problems such as difficult sealing of the battery, mismatching of battery components, rapid performance decay, short working life and high production cost. , The anode carbon deposition phenomenon will also cause the rapid attenuation of battery performance and the reduction of service life. Therefore, it is of great significance to develop battery system materials with good performance in the medium and low temperature range (below 850°C) to reduce the operating temperature of SOFC.

The ionic conductivity of LaGaO3 _- based materials reaches 0.1S/cm at 800 °C, which is an order of magnitude higher than that of the traditional electrolyte material YSZ (yttria-stabilized zirconia) under the same conditions, and is pure in a wide range of oxygen partial pressures. It is an ideal candidate material for intermediate temperature solid oxide fuel cell (ITSOFC) electrolyte. LaCrO ₃ -based materials can solve the carbon deposition on traditional anode materials (such as Ni-electrolyte) due to their high electron-ion conductivity, catalysis, and reforming properties. LaFeO ₃ -based materials have good catalytic activity for O ₂ , and their electronic conductivity at 800°C reaches 100-1000 S/cm. As a cathode material, its polarization effect is much smaller than that of commonly used cathode materials La _1-x Sr _x MnO ₃ . Therefore, these materials are promising ITSOFC materials. However, at present, people only study one of the above materials as the SOFC component material, and there is no report on using the three materials as the system material of a single cell at the same time.

Summary of the invention: The object of the present invention is to overcome the deficiencies of the prior art, provide a medium temperature solid oxide fuel cell system material and its battery and preparation method, and reduce the working temperature of SOFC.

The technical scheme of the present invention is: the material of the intermediate temperature solid oxide fuel cell (ITSOFC) system is a perovskite (ABO ₃ ) type electrode material, the electrolyte adopts a LaGaO ₃ base material with high ion conductivity, and the anode material adopts a LaCrO ₃ base material 1. The cathode adopts LaFeO ₃ -based materials; according to actual needs, doping elements can be added to the materials of each system, and by adjusting the type and amount of doping elements, the thermal expansion coefficient of the battery component materials is adjusted, and the electrolyte and There is good chemical compatibility between the electrode materials; the doping elements added can be Sr, Ca, Mg, Mn, Co, etc., and the specific addition amount can be adjusted according to actual needs to ensure good compatibility between the electrolyte and the electrode materials. Thermal matching and chemical compatibility are sufficient.

The intermediate temperature solid oxide fuel cell (ITSOFC) is composed of electrolyte, anode, cathode system materials, fuel, and sealing materials. The electrolyte, anode, and cathode materials of the battery are respectively LaGaO ₃ -based, LaCrO ₃ -based, and LaFeO ₃ -based perovskite For ore (ABO ₃ ) type materials, the supporting structure of the battery can be an electrolyte support structure or a cathode support structure. The electrolyte support structure battery is composed of a dense LaGaO ₃ -based material electrolyte substrate sintered on both sides with a porous LaCrO 3 -based material anode layer and a LaFeO ₃ -based material cathode layer, assembled in the _order of anode|electrolyte|cathode, and the anode contains hydrogen or A fuel such as methane (a hydrogen-rich gas) with air or oxygen in the cathode. The cathode support structure battery is composed of a LaFeO ₃ -based material porous structure cathode support with a dense LaGaO ₃ -based material electrolyte layer and a porous LaCrO ₃ -based material anode layer sequentially sintered on the same side, assembled in the order of anode|electrolyte|cathode, the anode There is a fuel (hydrogen-rich gas) such as hydrogen or methane in the cathode, and air or oxygen in the cathode.

The preparation method of the solid oxide fuel cell is as follows: first, the perovskite (ABO ₃ ) type battery material-LaGaO ₃ -based Powder materials, LaCrO ₃ -based powder materials _, LaFeO ₃ -based powder materials, and then prepare batteries according to the type of support structure; Prepare a dense electrolyte support substrate, and then use common film-forming techniques such as screen and coating, and use LaCrO ₃ -based materials and LaFeO ₃ -based materials to prepare porous LaCrO ₃ -based anode membranes on both sides of the electrolyte substrate. and LaFeO ₃ -based cathode film, and then assemble a single cell based on the anode|electrolyte|cathode three-in-one composite film, and then pass fuel such as hydrogen or methane at the anode, and pass air or oxygen at the cathode to produce a medium-temperature solid oxide Fuel cell (ITSOFC); if the battery adopts a cathode support structure, the traditional casting or pressing and sintering process is firstly used, and an appropriate amount of pore-forming agent (such as activated carbon, polyvinyl butyral, etc.) is added to the LaFeO ₃ -based powder material and After tape casting and sintering, a porous cathode support is made, and then a dense film is obtained on the same side of the cathode support successively with LaGaO ₃ -based materials and LaCrO ₃ -based materials using common film-forming techniques such as screen and coating. LaGaO ₃ -based electrolyte membrane and porous LaCrO ₃ -based anode membrane, and then a single cell is assembled based on the anode|electrolyte|cathode three-in-one composite membrane, and then fuel such as hydrogen or methane is fed into the anode, and air or gas is fed into the cathode. Oxygen to produce an intermediate temperature solid oxide fuel cell (ITSOFC).

The above-mentioned perovskite (ABO ₃ ) battery materials refer to LaGaO ₃ -based materials, LaCrO ₃ -based materials, and LaFeO ₃ -based materials. According to actual needs, doping elements Sr, Ca, Mg, and Mn can be added to these materials, respectively. , Co, etc., and by adjusting the type and amount of doping elements, the thermal expansion coefficient of the battery component material is adjusted, and at the same time, there is good chemical compatibility between the electrolyte and the electrode material ( The specific addition amount should be adjusted according to actual needs to ensure good thermal matching and chemical compatibility between the electrolyte and the electrode material. Generally, doping elements are added to the A-site and B-site of the ABO ₃ material, and the added doping The mole percentage of the element is 10-50%). After adding doping elements, LaGaO _3- based materials can be La _1-x Sr _x Ga _1-y Mg _y O _3-δ , La _1-x Sr _x Ga _1-yz Mg _y Co _z O _3-δ , etc., LaCrO _3- based materials can be La _1-x Sr _x Cr _{1-y Mny} O _3-δ , La _1-x Ca _x Cr _1-y Mny _{O 3-δ} , etc. LaFeO _3- based materials can be La _1-x Sr _x Fe _{1-y Mny} O _3-δ , La _1-x Sr _x Fe _1-y Co _y O _3-δ , La _1-xy Sr _x Ca _y Fe _1-z Co _z O _3-δ , etc. When preparing a LaGaO ₃ -based dense electrolyte support substrate or a LaFeO ₃ -based porous structure cathode support, according to the structural requirements of the SOFC electrolyte or cathode support, the ordinary pressing or tape casting and sintering process of such powder materials are used. The support body is generally a sheet-shaped dense substrate, and the cathode support body is generally a porous structure; because the conductivity of the electrolyte and the cathode material are relatively high, a support body with a large thickness can be prepared to obtain good mechanical properties. Film structure can be used; when using common film-forming techniques such as screen and coating, ethanol, glycerin and common binders (such as polyvinyl butyral, polyvinyl alcohol resin) can be used to combine perovskite electrode materials Mixed into slurry (the proportion of ethanol, glycerin and ordinary binder is determined according to actual needs), and then coated; connect the single cells in parallel or in series with connecting materials to obtain a battery stack, and then generate electricity.

Compared with the prior art, the present invention has the following advantages: 1. The electrolyte adopts _LaGaO3 base material with high ion conductivity, which can reduce the internal resistance of the whole battery; the anode material adopts _LaCrO3 base material, which can reduce the accumulation on the traditional anode. Carbon phenomenon; the cathode adopts LaFeO ₃ -based materials with high conductivity and good oxygen reduction performance, which can significantly reduce the cathode polarization loss.

2. The component materials of the entire battery can work at medium temperature, and the selection range of materials such as battery sealing and interconnection is wide.

3. The material of the whole battery is a perovskite material, and the influence of temperature on the crystal structure transformation of the material is similar or the same, and the stability of the battery is good; because the anode and the cathode have ion-electronic mixed conductivity, generally There is no need to incorporate metals or electrolytes therein to make composite electrodes.

4. There is good chemical compatibility between the electrolyte and the electrode material; the thermal expansion coefficient of various battery component materials can be adjusted by the type and amount of doping elements according to actual needs. These characteristics are very important to improve the performance of the battery and prolong the service life of the battery.

The electrolyte and the electrode material have good chemical and thermal compatibility, which can reduce the attenuation of battery performance; the anode material has good carbon deposition resistance, and has a good tolerance to fuels containing sulfur and nitrogen, which can expand the range of fuel choices; the cathode material The conductivity is very high, which can reduce the polarization loss of the cathode.

BRIEF DESCRIPTION OF THE DRAWINGS: The present invention will be further elaborated below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is the schematic diagram of electrolyte supporting structure battery of the present invention;

Fig. 2 is a schematic diagram of a battery with a cathode support structure of the present invention;

Fig. 3 is a flow chart of the preparation process of the electrolyte support structure battery of the present invention;

Fig. 4 is a flow chart of the manufacturing process of the cathode support structure battery of the present invention.

In the figure, 1-porous anode membrane, 2-dense electrolyte support, 3-porous cathode membrane, 4-porous anode membrane, 5-dense electrolyte membrane, 6-porous cathode support.

Specific embodiments: Example 1: As shown in Figures 1 and 3, the intermediate temperature solid oxide fuel cell (ITSOFC) is composed of electrolyte, anode, cathode system material, fuel, sealing material, etc., and adopts perovskite electrode material, The electrolyte is La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _3-δ material, the anode is La _0.7 Sr _0.3 Cr _0.5 Mn _0.5 O _3-δ material, and the cathode is La _0.6 Sr _0.4 Fe _0.8 Co _0.2 O _3-δ material. The battery is an electrolyte support structure, _which consists of a dense La _0.9 Sr 0.1 Ga _0.8 layer with a porous La 0.7 Sr _0.3 Cr _0.5 Mn _0.5 O _3-δ anode layer and a La _0.6 Sr _0.4 Fe _0.8 Co _0.2 O _3-δ cathode layer sintered on both sides _. The Mg _0.2 O _3-δ circular substrate is assembled in the order of anode|electrolyte|cathode. There is hydrogen in the anode and air in the cathode.

The preparation method of the ITSOFC is as follows: first, the La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _3-δ electrolyte powder material is synthesized by the traditional solid-state method, and La _0.7 Sr _0.3 Cr _0.5 Mn _0.5 O _3-δ is synthesized by the glycine-nitrate method Anode and La _0.6 Sr _0.4 Fe _0.8 Co _0.2 O _3-δ cathode powder materials, and then adopt the traditional press forming and sintering process, the La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _3-δ powder is pressed and sintered at 1480 ° C , to obtain a disc-shaped electrolyte support body with a diameter of 16mm and a thickness of 0.5mm; then, by ordinary screen printing method, La _0.7 Sr _0.3 Cr _0.5 Mn _0.5 O _3-δ and La _0.6 Sr _0.4 Fe _0.8 Co _0.2 O The _3-delta powder material is mixed with ethanol, glycerin and polyvinyl butyral to form a slurry (the mass percentages of ethanol, glycerin and binder are respectively 5%, 10%, and 3%), and the electrolyte support substrate La _0.7 Sr _0.3 Cr _0.5 Mn _0.5 O _3-δ anode film and La _0.6 Sr _0.4 Fe _0.8 Co _0.2 O _3-δ cathode film with a thickness of about 20 μm are coated on both sides (so that the effective area of the electrode film is 0.5 cm ² ), And sintered at 1250 ° C, so that the electrode film is evenly attached to the electrolyte support and has a porous structure; then a single cell is assembled on the basis of the anode | electrolyte | Introduce air (the air flow rate is 0.5 L/min, the hydrogen flow rate is 0.5 L/min), and the ITSOFC is produced (the battery operating temperature is 830° C.).

The open circuit voltage of the battery is 1.02V, which is close to the theoretical electromotive force, and the maximum power density of the battery is 300mW/cm ² ; after the battery runs for 50 hours, the open circuit voltage and output power have no obvious attenuation; No chemical reaction occurred during the preparation and operation of the battery.

Example 2: As shown in Figures 2 and 4, the intermediate temperature solid oxide fuel cell (ITSOFC) is composed of electrolyte, anode, cathode system material, fuel, sealing material, etc., and its electrolyte, anode and cathode are respectively made of La _0.8 Sr _0.2 Ga _0.8 Mg _0.16 Co _0.04 O _3-δ , La _0.75 Ca _0.25 Cr _0.5 Mn _0.5 O _3-δ and La _0.6 Sr _0.25 Ca _0.15 Fe _0.7 Co _0.3 O _3-δ perovskite materials. The battery is a cathode support structure, and the dense La _0.8 Sr _0.2 Ga _0.8 Mg _0.16 Co _0.04 O _3-δ electrolyte layer and the porous La _0.75 Ca _0.25 Cr _0.5 Mn _0.5 O _3-δ anode layer are sequentially sintered on the same side La _0.6 Sr _0.25 Ca _0.15 Fe _0.7 Co _0.3 O _3-δ porous structure cathode support, assembled in the order of anode|electrolyte|cathode, with methane in the anode and oxygen in the cathode.

The preparation method of the ITSOFC is as follows: firstly synthesize La _0.8 Sr _0.2 Ga _0.8 Mg _0.16 Co _0.04 O _3-δ electrolyte powder material, La _0.75 Ca _0.25 Cr _0.5 Mn _0.5 O _3-δ anode powder material by sol-gel method and La _0.6 Sr _0.25 Ca _0.15 Fe _0.7 Co _0.3 O _3-δ cathode powder materials, and then adopt the traditional press forming and sintering process, add the mass percentage of La _0.6 Sr _0.25 Ca _0.15 Fe _0.7 Co _0.3 O _3-δ powder to 3% activated carbon was pressed and sintered at 1300°C to obtain a porous structure cathode support body with a diameter of 16 mm and a thickness of 0.8 mm. Then, La _0.8 Sr _0.2 Ga _0.8 Mg _0.16 Co _0.04 O _3-δ and La _0.75 Ca _0.25 Cr _0.5 Mn _0.5 O _3-δ powder materials are mixed with ethanol, glycerin and polyvinyl alcohol resin to form a slurry (the mass percent of ethanol, glycerol and polyvinyl alcohol resin is 5% respectively , 10%, 2%), on the same side of the cathode support substrate, a La _0.8 Sr _0.2 Ga _0.8 Mg _0.16 Co _0.04 O _3-δ electrolyte membrane and a La _0.75 Ca _0.25 Cr _0.5 Mn _0.5 O _3-δ anode film, and sintered at 1450°C and 1300°C respectively, so that the dense electrolyte film and porous electrode film are attached to the cathode support successively and smoothly; then based on the anode|electrolyte|cathode three-in-one composite film Assemble a single cell, feed methane into the anode, and feed oxygen into the cathode (the flow rate of oxygen is 0.2L/min, and the flow rate of methane is 0.5L/min), that is, a medium-temperature solid oxide fuel cell (battery operating temperature is 850°C) .

The open circuit voltage of the battery is 0.7V, and the maximum power density of the battery is about 200mW/cm ² ; the open circuit voltage and output power have no obvious attenuation after accumulative operation of the battery for 50 hours; the XRD test results show that the electrode materials and electrolyte materials of the battery No chemical reaction occurred during the preparation and operation, and carbon deposition on the anode was not obvious; SEM detection showed that the physical structure of the cathode support, electrolyte and anode film did not deteriorate.

Embodiment 3: As shown in Figures 2 and 4, the intermediate temperature solid oxide fuel cell is composed of electrolyte, anode, cathode system material, fuel, sealing material, etc., and its electrolyte, anode and cathode are respectively made of La _0.9 Sr _0.1 Ga _0.8 Mg _0.16 Fe _0.04 O _3-δ , La _0.7 Sr _0.3 Cr _0.5 Co _0.5 O _3-δ and La _0.8 Sr _0.2 Fe _0.6 Mn _0.4 O _3-δ perovskite materials. The battery is a cathode support structure, which is sequentially sintered with a dense La _0.9 Sr _0.1 Ga _0.8 Mg _0.16 Fe _0.04 O _3-δ electrolyte layer and a porous La _0.7 Sr _0.3 Cr _0.5 Co _0.5 O _3-δ anode layer La _0.8 Sr on the same side _0.2 Fe _0.6 Mn _0.4 O _3-δ porous structure cathode support, assembled in the order of anode|electrolyte|cathode, with biomass gas in the anode and oxygen in the cathode.

The preparation method of the intermediate temperature solid oxide fuel cell is as follows: first, La _0.9 Sr _0.1 Ga _0.8 Mg _0.16 Fe _0.04 O _3-δ electrolyte powder material, La _0.7 Sr _0.3 Cr _0.5 Co _0.5 O ₃ are synthesized by citric acid-nitrate method _-δ anode powder material and La _0.8 Sr _0.2 Fe _0.6 Mn _0.4 O _3-δ cathode powder material. Then add 10% solvent, 5% activated carbon and 3% polyvinyl butyral to the La _0.8 Sr _0.2 Fe _0.6 Mn _0.4 O _3-δ powder, and tape-cast it, and dry it at 1300°C Sintering to obtain a porous structure cathode support with a diameter of 15mm and a thickness of 0.8mm, and then La _0.9 Sr _0.1 Ga _0.8 Mg _0.16 Fe _0.04 O _3-δ and La _0.7 Sr _0.3 Cr _0.5 Co _0.5 O _3-δ powder The material is mixed with ethanol, glycerin and polyvinyl butyral (the mass percentages of ethanol, glycerin and polyvinyl butyral are 5%, 10%, and 2% respectively), and then screen printing is used to print the slurry on the cathode The same side of the support substrate was coated with a La _0.9 Sr _0.1 Ga _0.8 Mg _0.16 Fe _0.04 O _3-δ electrolyte membrane and a La _0.7 Sr _0.3 Cr _0.5 Co _0.5 O _3-δ anode membrane with a thickness of about 30 μm. Sintering at ℃ and 1200℃, so that the dense electrolyte membrane and porous electrode membrane are attached to the cathode support in sequence; then a single cell is assembled based on the anode|electrolyte|cathode three-in-one composite membrane, and biomass is introduced into the anode Gas, feed oxygen into the cathode (the oxygen flow rate is 0.2L/min, the biomass gas flow rate is 0.8L/min), that is, ITSOFC is produced (the battery operating temperature is 850°C).

The open circuit voltage of the battery is 0.75V, and the maximum power density of the battery is about 150mW/cm ² ; after accumulative operation of the battery for 50 hours, the open circuit voltage and output power have no obvious attenuation; the XRD test results show that the electrode material and electrolyte material of the battery No chemical reaction occurred during the preparation and operation process, the anode maintained the perovskite structure and the carbon deposition phenomenon was not obvious; SEM detection showed that the physical structure of the cathode support, electrolyte and anode film did not deteriorate.

Claims (3)

1. A medium temperature solid oxide fuel cell is made up of electrolyte, anode, cathode system material and fuel, sealing material, it is characterized in that the electrolyte of battery, anode, cathode material are respectively LaGaO ₃ base, LaCrO ₃ base, LaFeO ₃ base Perovskite ABO ₃ type material; each electrolyte, anode, and cathode materials also contain one of the doping elements Mn, Co or a variety of Sr, Ca, Mg, Mn, Co, and the supporting structure of the battery is a cathode support structure , in the A-site and B-site of each electrolyte, anode and cathode material, the mole percentage content of the doping element added is 10-50%. 2. The intermediate temperature solid oxide fuel cell according to claim 1, characterized in that the cathode support body structure battery is sintered with dense _LaGaO3 base material electrolyte layer and porous _LaCrO3 base material anode layer successively by the same side _LaFeO3 base Material Porous structure cathode support body, assembled in order of anode|electrolyte|cathode, there is hydrogen or methane in the anode, and air or oxygen in the cathode. 3. A method for preparing a medium-temperature solid oxide fuel cell according to claim 1, characterized in that the perovskite battery material—LaGaO ₃ -based powder material, LaCrO ₃ -based powder is prepared by solid phase or wet chemical method Materials, LaFeO ₃ -based powder materials, first use traditional tape casting or pressing and sintering technology, use LaFeO ₃ -based powder materials to prepare porous structure cathode support body, and then use screen and coating common film-forming technology, use LaGaO ₃ Based powder material and LaCrO ₃ -based powder material, dense LaGaO ₃ -based electrolyte membrane and porous LaCrO ₃ -based anode membrane were obtained successively on the same side of the cathode support, and then anode|electrolyte|cathode three-in-one composite membrane A single cell is assembled on the basis, and hydrogen or methane fuel is fed into the anode, and air or oxygen is fed into the cathode to make a medium temperature solid oxide fuel cell.

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