阅读说明：本技术 准对称固体氧化物电解池的电极材料及其制备方法和应用 (Electrode material of quasi-symmetrical solid oxide electrolytic cell and preparation method and application thereof ) 是由 池波 田云峰 贾礼超 颜冬 蒲健 李箭 于 2020-05-28 设计创作，主要内容包括：本发明属于固体氧化物电解池领域,并具体公开了准对称固体氧化物电解池的电极材料及其制备方法和应用。该电极材料的分子式为La<Sub>0.6+x</Sub>Ca<Sub>0.4-x</Sub>Fe<Sub>0.9-y</Sub>Ni<Sub>0.1+y</Sub>O<Sub>3-δ</Sub>,其中δ表示氧空位的数量,并且0≤x≤0.3,0≤y≤0.3。本发明提供的电极材料在还原气氛下可原位析出Fe-Ni纳米合金颗粒和CaO,其中Fe-Ni纳米合金颗粒有效降低了电极的极化电阻,并且还原后析出的CaO能够在高温下吸附CO<Sub>2</Sub>,生成的CaCO<Sub>3</Sub>分解温度低,通过简单的气体变换,不会有碳酸盐沉积在电极表面,因而具有良好的自修复性能,同时该电极材料在电解过程中不需要还原气氛保护,适合作为高温对称固体氧化物电解池的电极材料。(The invention belongs to the field of solid oxide electrolytic cells, and particularly discloses an electrode material of a quasi-symmetric solid oxide electrolytic cell, and a preparation method and application thereof. The molecular formula of the electrode material is La 0.6+x Ca 0.4‑x Fe 0.9‑y Ni 0.1+y O 3‑ Wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3. The electrode material provided by the invention can in-situ precipitate Fe-Ni nano alloy particles and CaO in a reducing atmosphere, wherein the Fe-Ni nano alloy particles effectively reduce the polarization resistance of the electrode, and the CaO precipitated after reduction can adsorb CO at high temperature 2 CaCO produced 3 The decomposition temperature is low, no carbonate is deposited on the surface of the electrode through simple gas conversion, so that the electrode material has good self-repairing performance, does not need reduction atmosphere protection in the electrolytic process, and is suitable for serving as high-temperature symmetrical solid oxide electrodeElectrode material of the electrolytic cell.)

1. An electrode material of a quasi-symmetrical solid oxide electrolytic cell is characterized in that the molecular formula of the electrode material is La_0.6+xCa_0.4-xFe_0.9-yNi_0.1+yO_3-Wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3.

2. A method of preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to claim 1, comprising the steps of:

s1 reacting La (NO)₃)₃·6H₂O：Ca(NO₃)₂：Fe(NO₃)₃·9H₂O：Ni(NO₃)₂·6H₂O is as (0.6+ x): (0.4-x): (0.9-y): mixing and dissolving the components in a molar ratio of (0.1+ y) to prepare a metal solution, wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3;

s2, sequentially adding ethylene diamine tetraacetic acid and citric acid into the metal solution to obtain a mixed solution, and then adjusting the pH of the mixed solution by using ammonia water to form sol;

s3, heating the sol to evaporate water until gel is formed, drying the gel to obtain an oxide precursor, and finally calcining the oxide precursor to obtain the electrode material of the quasi-symmetrical solid oxide electrolytic cell.

3. The method for preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to claim 2, wherein in step S2, the ratio of metal ions in the mixed solution: ethylene diamine tetraacetic acid: the molar ratio of the citric acid is 1 (1-1.3) to 1.5-2.

4. The method for preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to claim 2, wherein in step S2, the pH of the mixed solution is adjusted to 6 to 8 using ammonia water.

5. The method for preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to claim 2, wherein the sol is heated at a temperature of 80 to 120 ℃ to form the gel in step S3.

6. The method for preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to claim 2, wherein the gel is dried at a temperature of 200 to 300 ℃ in step S3.

7. The method for preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell according to any one of claims 2 to 6, wherein the oxide precursor is calcined at a temperature of 800 ℃ to 1000 ℃ in step S3.

8. Use of an electrode material for a quasi-symmetrical solid oxide electrolytic cell according to claim 1 in an electrolytic cell.

Technical Field

The invention belongs to the field of solid oxide electrolytic cells, and particularly relates to an electrode material of a quasi-symmetrical solid oxide electrolytic cell, and a preparation method and application thereof.

Background

The solid oxide electrolytic cell is the reverse process of the fuel cell, and can efficiently electrolyze water to produce hydrogen and electrolyze CO by combining renewable energy sources such as solar energy, wind energy and the like with waste heat generated by factories₂And the greenhouse effect is relieved. Conventional solid oxide electrolysis cells typically comprise an anode and a cathode made of different materials. The anode is typically composed of a cermet and the cathode material is typically a perovskite oxide. Due to the different material composition of its electrodes, at least two heat treatment processes are required for the manufacture of solid oxide electrolysis cells. In actual production, more heat treatment steps mean more energy consumption.

The manufacturing costs of the solid oxide electrolytic cell can be significantly reduced if the same material is used for both electrodes. In addition, the use of the same material in the cathode and anode of a solid oxide electrolytic cell may improve the thermomechanical compatibility of the cell components, since the cell now has only one electrode-electrolyte interface. The symmetrical solid oxide electrolytic cell can minimize the preparation process, reduce the manufacturing cost, and improve the compatibility between the electrolyte and the electrode, which has attracted great attention.

Although symmetrical solid oxide cells have bright application prospects, the electrode materials of symmetrical cells must have good stability against Oxygen Evolution Reaction (OER) and CO under the operating conditions of the solid oxide cells₂The high electrocatalytic performance of the reduction reaction, so that the search for high-performance electrode materials is the key to realizing the breakthrough of the performance of the symmetrical electrolytic cell. The symmetric electrode system comprises LSCM, Sr₂Fe_1.5Mo_0.5O_6-，La_0.3Sr_0.7Fe_0.7Cr_0.3O_3-，La_0.3Sr_0.7Fe_0.7Ti_0.3O_3-And other SrFeO based_3-Have been explored in solid oxide electrolytic cells, but they still suffer from lower electrocatalytic properties compared to conventional electrolytic cells.

Disclosure of Invention

In view of the above disadvantages and/or improvement needs of the prior art, the present invention provides an electrode material for a quasi-symmetric solid oxide electrolytic cell, and a preparation method and an application thereof, wherein the electrode material can in-situ precipitate nano-metal Fe-Ni alloy particles and calcium oxide in a reducing atmosphere, the Fe-Ni nano alloy particles can effectively reduce the polarization resistance of an electrode, and the calcium oxide can ensure that the electrode material has good self-repairing performance, and is particularly suitable for application scenarios of the quasi-symmetric solid oxide electrolytic cell.

To achieve the above object, according to one aspect of the present invention, there is provided an electrode material for a quasi-symmetric solid oxide electrolytic cell, the electrode material having the formula La_0.6+xCa_0.4-xFe_0.9-yNi_0.1+yO_3-Wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3.

According to another aspect of the present invention there is provided a method of preparing an electrode material for a quasi-symmetric solid oxide electrolytic cell as defined above, the method comprising the steps of:

s1 reacting La (NO)₃)₃·6H₂O：Ca(NO₃)₂：Fe(NO₃)₃·9H₂O：Ni(NO₃)₂·6H₂O is as (0.6+ x): (0.4-x): (0.9-y): mixing and dissolving the components in a molar ratio of (0.1+ y) to prepare a metal solution, wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3;

s2, sequentially adding ethylene diamine tetraacetic acid and citric acid into the metal solution to obtain a mixed solution, and then adjusting the pH of the mixed solution by using ammonia water to form sol;

s3, heating the sol to evaporate water until gel is formed, drying the gel to obtain an oxide precursor, and finally calcining the oxide precursor to obtain the electrode material of the quasi-symmetrical solid oxide electrolytic cell.

As a further preference, in step S2, the ratio of metal ions in the mixed solution: ethylene diamine tetraacetic acid: the molar ratio of the citric acid is 1 (1-1.3) to 1.5-2.

More preferably, in step S2, the pH of the mixed solution is adjusted to 6 to 8 with ammonia water.

Further preferably, in step S3, the sol is heated at a temperature of 80 to 120 ℃ to thereby form the gel.

Further preferably, in step S3, the gel is dried at a temperature of 200 to 300 ℃.

Further preferably, in step S3, the oxide precursor is calcined at a temperature of 800 to 1000 ℃.

According to a further aspect of the invention there is provided the use of an electrode material for a quasi-symmetric solid oxide electrolytic cell as described above in an electrolytic cell.

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. the invention provides a quasi-symmetrical solid oxide electrolytic cell electrode material, which can precipitate nano metal Fe-Ni alloy particles and calcium oxide in situ under a reducing atmosphere, wherein the precipitated Fe-Ni alloy grows on the surface of a perovskite substrate in a nano particle form, and the existence of the Fe-Ni nano alloy particles greatly improves the catalytic activity and reduces the polarization resistance of the electrode; meanwhile, calcium oxide precipitated on the surface after reduction is good CO₂Adsorbent capable of effectively adsorbing CO at high temperature₂And with SrCO₃Comparative CaCO₃The decomposition temperature is low, and no carbonate is deposited on the surface of the electrode through simple gas conversion, so that the electrode has good self-repairing performance; more importantly, the electrode material provided by the invention does not need the protection of reducing atmosphere in the electrolytic process, and is suitable for being used as high temperatureElectrode material for a symmetric solid oxide electrolytic cell;

2. in addition, the invention provides a preparation method of the electrode material of the quasi-symmetrical solid oxide electrolytic cell, wherein the electrode material can be ensured to have excellent stability and the polarization resistance of the electrode can be reduced by optimizing various conditions in the preparation process, so that the electrolytic cell can be ensured to work stably and efficiently.

Drawings

FIG. 1 is a flow chart of the preparation of electrode material for quasi-symmetrical solid oxide electrolytic cells provided by the present invention;

FIG. 2 is an X-ray diffraction pattern of the electrode material prepared in the preferred embodiment 1 of the present invention, (a) is an XRD pattern of the electrode material before and after reduction, and (b) is an XRD pattern of the electrode material in CO₂Comparing the atmosphere with the atmosphere before and after treatment in the reducing atmosphere and obtaining XRD patterns after cyclic treatment for 7 times in the two atmospheres;

FIG. 3 is a scanning electron micrograph of an electrode material prepared according to a preferred embodiment 2 of the present invention, wherein (a) is a quasi-symmetrical cell morphology, (b) is a pre-reduced cathode, and (c) is an unreduced anode;

FIG. 4 is the electrochemical performance of the quasi-symmetrical solid oxide electrolytic cell prepared in the preferred embodiment 3 of the present invention at different temperatures, wherein (a) is the current density versus voltage curve, and (b) is the impedance spectrum in the open circuit state.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in FIG. 1, the embodiment of the invention provides an electrode material of a quasi-symmetrical solid oxide electrolytic cell, and the molecular formula of the electrode material is La_0.6+xCa_0.4-xFe_0.9-yNi_0.1+yO_3-In which is shownThe number of oxygen vacancies is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3.

According to another aspect of the present invention, there is provided a method for preparing the electrode material for the quasi-symmetric solid oxide electrolytic cell, the method comprising the steps of:

s1 reacting La (NO)₃)₃·6H₂O：Ca(NO₃)₂：Fe(NO₃)₃·9H₂O：Ni(NO₃)₂·6H₂O is as (0.6+ x): (0.4-x): (0.9-y): mixing and dissolving the components in the molar ratio of (0.1+ y) in deionized water, and uniformly stirring the components on a magnetic stirrer to prepare a metal solution, wherein x is more than or equal to 0 and less than or equal to 0.3, and y is more than or equal to 0 and less than or equal to 0.3;

s2, adding ethylene diamine tetraacetic acid and citric acid into the metal solution in sequence to obtain a mixed solution, and ensuring that metal ions in the mixed solution are: ethylene diamine tetraacetic acid: the molar ratio of citric acid is 1 (1-1.3) to 1.5-2, so that the citric acid fully generates a complex reaction, and then ammonia water is used for adjusting the pH value of the mixed solution to 6-8 to form sol;

s3 is stirred and heated in an oil bath kettle at the temperature of 80-120 ℃ to evaporate water until gel is formed, the obtained gel is placed in an oven and dried at the temperature of 200-300 ℃ for 5-12 hours to obtain black loose oxide precursor, and finally the oxide precursor is ground in a mortar and placed in a ceramic crucible and calcined in a muffle furnace at the temperature of 800-1000 ℃ to prepare the electrode material of the quasi-symmetrical solid oxide electrolytic cell.

According to another aspect of the invention, the application of the electrode material in a quasi-symmetrical solid oxide electrolytic cell is provided, and the quasi-symmetrical solid oxide electrolytic cell is prepared by using a YSZ support body with the diameter of 12-25 mm and the thickness of about 0.2-0.5 mm. Firstly, GDC slurry is printed on two sides of YSZ in a screen printing mode to serve as a barrier layer and sintered, and then La is prepared on two sides of GDC in a screen printing mode_0.6+xCa_0.4-xFe_0.9-yNi_0.1+yO_3-And sintering the electrode layer at 950-1100 ℃ for 2-4 h to form good contact with the electrolyte layer. Coating Pt slurry on the prepared symmetrical battery to be used as a current collecting layer, and calcining at 700-850 ℃ for 1h to EAnd 3h, burning off organic matters, and sealing the organic matters on a self-made test fixture by using ceramic glue. After the temperature is raised to the testing temperature (750-850 ℃), one side of the symmetrical battery is introduced into reducing atmosphere to reduce for 2-6 h, so that Fe-Ni alloy is separated out and calcium oxide is formed, and the other side is exposed in the air, thereby forming the quasi-symmetrical solid oxide electrolytic cell.

To test the performance of the quasi-symmetric solid oxide electrolytic cell, the quasi-symmetric solid oxide electrolytic cell was heated to electrolyze CO₂The temperature is measured (750-850 ℃), and then CO with a certain flow rate is introduced₂(30 sccm-50 sccm), operating at a fixed electrolysis voltage for a period of time, and stopping CO removal₂Introducing reducing gas into the electrode for treating for 10-60 min, and electrolyzing CO again₂And (5) carrying out experiments. Tests show that the electrolytic performance of the quasi-symmetric solid oxide electrolytic cell can be recovered to the initial performance, and the quasi-symmetric solid oxide electrolytic cell has good self-repairing performance.

The invention is further illustrated by the following examples.