CN114045520A

CN114045520A - Oxygen electrode for hydrogen production by solid oxide electrolysis and preparation method thereof

Info

Publication number: CN114045520A
Application number: CN202111546147.7A
Authority: CN
Inventors: 邵志刚; 唐帅; 赵哲
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2022-02-15
Anticipated expiration: 2041-12-15
Also published as: CN114045520B

Abstract

The invention belongs to the field of solid oxide electrolytic cells, and relates to a novel oxygen electrode for hydrogen production of a solid oxide electrolytic cell and a preparation method thereof. The oxygen electrode comprises LSM-YSZ oxygen electrode and LaA_xB_1‑ _xO_3‑δ‑La_yC_1‑yO_2‑δA composite, said LaA_xB_1‑xO_3‑δ‑La_yC_1‑yO_2‑δThe composite is attached to the inner and outer surfaces of the LSM-YSZ oxygen electrode; wherein x is more than or equal to 0.1 and less than or equal to 0.9, y is more than or equal to 0.1 and less than or equal to 0.9, and delta represents an oxygen vacancy value; a and B are respectively selected from one or more of Ce, Pr, Nd, Sm, Gd, Yb, Ni and Fe, and C is one or more of Ce, Mn, Nd, Bi, Gd, Yb, Ni and Fe. Compared with the traditional LSM electrode or the LSM electrode impregnated with single component, the electrode prepared by the inventionThe novel cobalt-free oxygen electrode significantly improves the performance of the electrolytic cell.

Description

Oxygen electrode for hydrogen production by solid oxide electrolysis and preparation method thereof

Technical Field

The invention belongs to the field of solid oxide electrolytic cells, and particularly relates to a cobalt-free high-performance oxygen electrode for hydrogen production by solid oxide electrolysis.

Background

The increase in the consumption of limited fossil fuels not only poses a serious energy crisis, but also causes environmental problems such as global warming and air pollution. Therefore, the development of renewable clean energy such as wind energy, tidal energy, solar energy and the like is promoted. However, due to regional differences and unstable energy supply, these energy sources need to be stored in more reliable carriers. H₂The energy storage carrier can be used as an energy carrier for transportation and storage of renewable energy sources (such as solar energy and wind energy), and has wide application prospect in the future. Therefore, many hydrogen production technologies have been developed, such as steam reforming. Wherein, the hydrogen production by water electrolysis based on Solid Oxide Electrolytic Cells (SOECs) has the advantages of cleanness, high efficiency, energy conservation, environmental protection and the like. The required electric energy can be from intermittent renewable energy sources such as wind energy, solar energy and the like, and the heat can be from waste heat of a factory. The technology can effectively combine electric energy and heat energy and is widely concerned.

In the production of hydrogen in solid oxide electrolysis cells, the slow kinetics of oxygen evolution at the anode is a major factor limiting the SOEC performance. The strontium-doped lanthanum manganate (LSM-YSZ) composite material as the traditional anode material has higher chemical and structural stability, and YSZ (Y)₂O₃Stabilized ZrO₂) The electrolyte has good compatibility, but its Oxygen Evolution Reaction (OER) activity is insufficient due to its small ionic conductivity. In order to improve the activity of the LSM-YSZ electrode, most of the current improvement methods are to dope elements such as cobalt in the LSM to improve the electron conductivity of the oxygen electrode, but due to the high thermal expansion coefficient of cobalt elements and chromium poisoning, cobalt-containing materials are generally difficult to ensure the stability of the battery; other materials have also been reported, such as BaCo_xFe_yZr_mY_1-x-y-mO_3-δ(BCFZY)，Ba_1-xSr_xCo_1-yFe_yO_3-δ(BSCF) and the like, but these materials are not suitable for high temperature electrolytic cells and the hydrogen production efficiency is to be improved.

Disclosure of Invention

Compared with the traditional LSM electrode or the single impregnated electrode of the LSM, the oxygen electrode prepared by the invention obviously improves the performance of an electrolytic cell.

The technical scheme of the invention is as follows:

an oxygen electrode of solid oxide electrolytic cell comprises LSM-YSZ oxygen electrode and LaA_xB_1-xO_3-δδ-La_yC_1-yO_2-δA complex; the LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe composite is attached to the inner and outer surfaces of the LSM-YSZ oxygen electrode; wherein x is more than or equal to 0.1 and less than or equal to 0.9, y is more than or equal to 0.1 and less than or equal to 0.9, delta represents an oxygen vacancy value and is a general expression of an oxide material, and delta is more than or equal to 0 and less than or equal to 0.1;

the LaA_xB_1-xO_3-δThe A and B are respectively selected from one or more of Ce, Pr, Nd, Sm, Gd, Yb, Ni and Fe, and the A and B are different elements; the La_yC_1-yO_2-δC in the material is one or more of Ce, Mn, Nd, Bi, Gd, Yb, Ni and Fe; the LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δIn a composite, LaA_xB_1-xO_3-δAnd La_yC_1-yO_2-δThe molar ratio of (A) to (B) is 0.5-2: 1; the LSM has a chemical formula of La_zSr_1-zMnO_3-δZ is more than or equal to 0.1 and less than or equal to 0.9; YSZ of the formula Y_mZr_1-mO₂，0.1≤m≤0.9。

In the above technical solution, further, the LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe average particle size of the nanoparticles is 10-50 nm; the LaA_xB_1-xO_3-δThe molar ratio of the metal ions A to B is 0.1-10: 1; the La_yC_1-yO_2-δThe molar ratio of the La and C metal ions is 0.1-10: 1.

In the above technical solution, further, the thickness of the oxygen electrode of the solid oxide electrolytic cellThe degree is 20-60 mu m; the LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe amount of the compound is 1 to 15 weight percent of the mass of the LSM-YSZ oxygen electrode.

The invention also provides a preparation method of the oxygen electrode of the solid oxide electrolytic cell, which comprises the following steps:

s1, preparing an LSM-YSZ oxygen electrode;

s2, preparation LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δSolution: according to chemical formula LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δWeighing A, B, C soluble metal salt powder and lanthanum soluble metal salt powder, dissolving in water, adding complexing agent, heating and stirring, and adjusting the pH of the solution to be less than or equal to 1 after dissolving;

s3, impregnation and roasting: and (4) dipping the LSM-YSZ oxygen electrode prepared in the step (S1) in the solution prepared in the step (S2), and roasting at 700-1000 ℃ for 3-4 h after dipping to obtain the solid oxide electrolytic cell oxygen electrode.

In the above technical solution, further, in step S2, LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δMiddle LaA_xB_1-xO_3-δThe concentration of the solution is 0.1-2 mol/L, LaA_xB_1-xO_3-δ-LayC_1-yO_2-δMiddle La_yC_1-yO_2-δThe concentration of the solution is 0.1-2 mol/L, the addition amount of the complexing agent is 0.5-2.7 times of the total metal ion molar amount, the complexing agent is any one of ammonium citrate, glycine, urea, EDTA and citric acid, the heating temperature is 60-90 ℃, and the stirring time is 2-10 hours; in step S3, the number of dipping times is 1-5.

In the above technical solution, further, the preparation method of the oxygen electrode in step S1 includes the following steps:

(1) preparing LSM anode powder:

a. according to the formula La of LSM_zSr_1-zMnO_3-δWeighing soluble metal salt powder of corresponding metal, dissolving in waterAdding a complexing agent with the molar weight of 0.5-2.7 times of the total metal ions, heating and stirring at 60-90 ℃ for 15-20 min, and adjusting the pH of the solution to be less than or equal to 1 after dissolution; continuously evaporating at 60-90 ℃ until the solution becomes transparent gel liquid;

b. heating the gel-like substance at 200-500 ℃ for 10-30 min until self-propagating combustion is carried out to form fluffy powder, thus obtaining primary powder; the primary powder is LSM primary powder;

c. calcining the primary powder at 700-1000 ℃ to form a phase, wherein the calcining time is 5-10 h, and grinding the primary powder through a 180-mesh steel screen to obtain secondary powder; the secondary powder is LSM secondary powder;

d. mixing the secondary powder with YSZ powder, adding a solvent A, uniformly mixing, drying the solvent, grinding, and sieving by a 180-mesh steel sieve to obtain mixed powder; the solvent A is one or more of ethanol, terpineol and n-butanol;

(2) preparing anode slurry: and (2) adding a binder into the mixed powder obtained in the step (1), fully grinding, coating on a cathode-supported semi-electrolytic cell sheet or an electrolyte-supported semi-electrolytic cell sheet, and naturally drying to obtain the semi-electrolytic cell sheet.

(3) Roasting: and (3) calcining the semi-electrolytic cell sheet obtained in the step (2) at 700-1000 ℃ for 3-5 h to obtain the oxygen electrode obtained in the step S1.

In the technical scheme, the mass ratio of the secondary powder to the YSZ powder is 1: 2-2: 1; the mass ratio of the mixed powder to the binder is 10: 1-2: 1.

In the above technical solution, further, the binder is terpineol with 6 wt% of ethyl cellulose.

In the above technical solution, further, the complexing agent is any one of ammonium citrate, glycine, urea, EDTA, and citric acid.

In the above technical solution, further, in the cathode-supported half electrolytic cell sheet, the cathode supporting layer is made of Ni-YSZ; in the electrolyte-supported half-cell plate, the material of the electrolyte supporting layer is YSZ.

In the technical scheme, the cathode-supported or electrolyte-supported semi-electrolytic cell sheet is prepared by tape casting, calendaring and powder dry pressing.

Advantageous effects

(1) The invention adds active component LaA into LSM-YSZ anode_xB_1-xO_3-δ-La_xC_1-xO_2-δThe nano particles can obviously improve the electrolytic performance of the electrolytic cell. LaA_xB_1-xO_3-δThe addition of (2) is beneficial to improving the performance of the electrolytic cell, but the high particle activity is easy to cause the agglomeration of particles so as to cause the performance attenuation of the cell; la_yC_1-yO_2-δThe component properties are relatively stable. When it is mixed with LaA_xB_1-xO_3-δWhen added together as an active ingredient to LSM-YSZ, LaA_xB_1-xO_3-δAnd La_yC_1-yO_2-δGenerates synergistic effect, inhibits the coarsening of particles and enhances the stability of the electrode. Synthesized LaA of the present invention_xB_1-xO_3-δ-La_yC_1-yO_2-δThe nano particles will LaA_xB_1- _xO_3-δAnd La_yC_1-yO_2-δMeanwhile, as an active component for impregnation, the catalyst has more surface oxygen vacancies and higher lattice oxygen mobility, and accelerates the oxygen evolution reaction in a steam electrolysis mode. LSM-YSZ @ LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe novel oxygen electrode can improve the catalytic activity of the oxygen electrode on the basis of better chemical stability, thereby increasing the electrochemical performance of the battery.

(2) In addition, according to the test comparison of the electrolytic cell, LaA is not soaked compared with the traditional method_xB_1-xO_3-δ-La_yC_1- _yO_2-δNanoparticulate LSM electrodes and LSM-YSZ @ LaA_xB_1-xO_3-δOr LSM-YSZ @ La_yC_1-yO_2-δThis single component impregnated electrode, LSM-YSZ @ LaA in the present invention_xB_1-xO_3-δ-La_yC_1-yO_2-δThe cobalt-free oxygen electrode has significantly higher hydrogen production performance in electrolytic cell tests.

(3) The novel oxygen electrode of the solid oxide electrolytic cell is prepared by firstly preparing LSM powder and LaA by adopting an ammonium citrate method_xB_1-xO_3-δ-La_yC_1-yO_2-δAnd preparing the substrate of the oxygen electrode by adopting a slurry coating method or a screen printing method, and finally adding active components by adopting a permeation method, thereby obtaining the novel oxygen electrode of the solid oxide electrolytic cell for efficiently producing hydrogen.

(4) The anode slurry formula adopted by the invention comprises LSM-YSZ mixed powder and a binder. The oxygen electrode is prepared by mixing LSM and YSZ powder, so that the compatibility of the electrolytic cell with electrolyte is improved, and the problems of thermal matching and the like can be effectively solved. The addition of the binder is to make the dispersed particles or clusters stick together on a submicroscopic scale, which is beneficial to the subsequent calcination molding for preparing the oxygen electrode. The content of the binder is added according to the particle size of the powder, and when the particle size of the powder is smaller, relatively more binder needs to be added to ensure that the slurry can be fully bonded.

Drawings

FIG. 1 is a SEM image of a cross-section of an LSM-YSZ oxygen electrode of comparative example 1;

FIG. 2 is a LSM-YSZ @ LaNi of comparative example 2_0.4Fe_0.6O_3-δSEM image of oxygen electrode cross section;

FIG. 3 is LSM-YSZ @ La of comparative example 3_0.45Ce_0.55O_2-δSEM image of oxygen electrode cross section;

FIG. 4 is LSM-YSZ- @ LaNi of example 1_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δSEM image of oxygen electrode cross section;

FIG. 5 shows LSM-YSZ, LSM-YSZ @ LaNi at 725 deg.C_0.4Fe_0.6O_3-δ、LSM-YSZ@La_0.45Ce_0.55O_2-δ、LSM-YSZ@LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δImpedance spectrum of (1).

FIG. 6 shows LSM-YSZ, LSM-YSZ @ LaNi at 800 deg.C_0.4Fe_0.6O_3-δ、LSM-YSZ@La_0.45Ce_0.55O_2-δ、LSM-YSZ@LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δVoltage-current density graph of (a).

Detailed Description

The invention is further illustrated but is not in any way limited by the following specific examples. In the following examples and comparative examples, the range of δ is 0. ltoreq. δ.ltoreq.0.1.

Comparative example 1:

the preparation method of the oxygen electrode of the solid oxide electrolytic cell comprises the following steps:

(1) synthesizing La by adopting ammonium citrate method_0.8Sr_0.2MnO_3-δ(delta is more than or equal to 0 and less than or equal to 0.1) anode powder

Respectively preparing La with the molar concentration of 0.5mol/L³⁺、Sr²⁺、Mn³⁺The nitrate solution of La is accurately transferred according to the proportion of 4: 1: 5³⁺、Sr²⁺、Mn³⁺In a 500ml beaker. Heating and stirring at 60 deg.C for 20min to obtain mixed La³⁺、Sr²⁺、Mn³⁺A nitrate solution of (a). Then, according to the ammonium citrate: adding ammonium citrate (analytically pure) at a total metal ion molar ratio of 1.5: 1, heating and stirring, adjusting pH of the solution to 8 with ammonia water (analytically pure) to make the solution clear and transparent, heating and stirring at 70 deg.C to evaporate the solvent until the solution becomes gel, pouring into 1000ml evaporation dish, heating with electric furnace to make the system self-spread and burn to obtain fluffy powder, collecting the obtained primary powder, roasting at 1000 deg.C in muffle furnace for 6h, grinding, and sieving with 180 mesh steel sieve to obtain La_0.8Sr_0.2MnO_3-δAnd (3) anode powder.

(2)La_0.8Sr_0.2MnO_3-δPreparation of-YSZ oxygen electrode

Mixing La prepared in (1)_0.8Sr_0.2MnO_3-δAnode powder and YSZ powder (8% by mol of Y)₂O₃Stabilized ZrO₂(Tosho, Japan)) in a mass ratio of 3: 2, adding ethanol and grinding to mix well, then drying the solvent under a baking lamp, then transferring to a mortar for grinding, and then sievingGrinding with a 180-mesh steel sieve, adding binder (terpineol containing 6 wt% of ethyl cellulose), coating 0.0080g on a cathode-supported half electrolytic cell sheet by a slurry coating method, and sintering in a muffle furnace at 1000 ℃ for 3h to obtain La_0.8Sr_0.2MnO_3-δ-YSZ oxygen electrode.

(3) And (3) testing of SOEC: the electrolytic test is carried out on a self-assembled battery evaluation device at 700-800 ℃, and the measured impedance spectrogram and the voltage-current density curve are respectively shown in fig. 5 and fig. 6.

Fig. 1 shows a SEM image of the oxygen electrode cross-section of LSM-YSZ, where LSM and YSZ are uniformly distributed and in intimate contact in the LSM-YSZ oxygen electrode, as shown in fig. 1.

Comparative example 2:

(1) synthesizing La by adopting ammonium citrate method_0.8Sr_0.2MnO_3-δAnd (3) anode powder.

Respectively preparing La with the molar concentration of 0.5mol/L³⁺、Sr²⁺、Mn³⁺The nitrate solution of La is accurately transferred and weighed according to the proportion of 4: 1: 5³⁺、Sr²⁺、Mn³⁺In a 500ml beaker. Heating and stirring at 60 deg.C for 20min to obtain mixed La³⁺、Sr²⁺、Mn³⁺A nitrate solution of (a). Then, according to the ammonium citrate: adding ammonium citrate (analytically pure) at a total metal ion molar ratio of 1.5: 1, heating and stirring, adjusting pH of the solution to 8 with ammonia water (analytically pure) to make the solution clear and transparent, heating and stirring at 70 deg.C to evaporate the solvent until the solution becomes gel, pouring into 1000ml evaporation dish, heating with electric furnace to make the system self-spread and burn to obtain fluffy powder, collecting the obtained primary powder, roasting at 1000 deg.C in muffle furnace for 6h, grinding, and sieving with 180 mesh steel sieve to obtain La_0.8Sr_0.2MnO_3-δAnd (3) anode powder.

(2)La_0.8Sr_0.2MnO_3-δPreparation of-YSZ oxygen electrode

Mixing La prepared in (1)_0.8Sr_0.2MnO_3-δAnode powder and YSZ powder (Mo)Y of 8%₂O₃Stabilized ZrO₂(Tosho, Japan)) in a mass ratio of 3: 2, adding ethanol, grinding to mix uniformly, then placing the mixture under a baking lamp to dry the solvent, then transferring the mixture into a mortar to grind, grinding the ground mixture through a 180-mesh steel sieve, adding a binder (terpineol containing 6 wt% of ethyl cellulose), coating 0.0080g of the mixture on a cathode-supported half electrolytic cell sheet by a slurry coating method, and then placing the cathode-supported half electrolytic cell sheet in a muffle furnace to sinter the cathode-supported half electrolytic cell sheet for 3 hours at 1000 ℃ to obtain La_0.8Sr_0.2MnO_3-δ-YSZ oxygen electrode.

(3) Impregnation solution LaNi_0.4Fe_0.6O_3-δPreparation of

Respectively preparing La with the molar concentration of 1mol/L³⁺、Ni²⁺、Fe³⁺The nitrate solution of La is accurately transferred and weighed according to the proportion of 5: 2: 3³⁺、Ni²⁺、Fe³⁺In a 500ml beaker. Heating and stirring at 60 deg.C for 20min to obtain mixed La³⁺、Ni²⁺、Fe³⁺A nitrate solution of (a). Ammonium citrate (analytical grade) was then added: heating and stirring to total metal cation molar ratio of 1.3, adjusting pH of the solution to 1 with nitric acid (analytically pure), making the solution clear and transparent, adding the solution to constant volume in 100ml volumetric flask, and adding LaNi_0.4Fe_0.6O_3-δThe concentration of (2) is 0.5 mol/L.

(4)LSM-YSZ-LaNi_0.4Fe_0.6O_3-δOxygen electrode preparation

Using microliter injector to take 4 microliter of LaNi prepared in step (3)_0.4Fe_0.6O_3-δInjection of solution into La_0.8Sr_0.2MnO_3-δVacuum dipping the surface of YSZ oxygen electrode, roasting at 800 ℃ for 3h to make the dipping solution enter the interior of the anode, dipping the dipping solution into the surface and the micropores of the oxygen electrode, and finally obtaining LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δAn oxygen electrode.

(5) And (3) testing of SOEC: the electrolytic test is carried out on a self-assembled battery evaluation device at 700-800 ℃, and the measured impedance spectrogram and the voltage-current density curve are respectively shown in fig. 5 and fig. 6.

FIG. 2 shows LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δSEM image of oxygen electrode cross section of (1), as shown in FIG. 2, at LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δIn the oxygen electrode, LaNi_0.4Fe_0.6O_3-δThe nanoparticles uniformly covered the surface of the LSM and YSZ particles.

Comparative example 3:

(2)La_0.8Sr_0.2MnO_3-δPreparation of-YSZ oxygen electrode

Mixing La prepared in (1)_0.8Sr_0.2MnO_3-δAnode powder and YSZ powder (8% by mol of Y)₂O₃Stabilized ZrO₂(Tosho, Japan)) in a mass ratio of 3: 2, adding ethanol and grinding to mix them uniformly, then drying the solvent under a baking lamp, then transferring to a mortar for grinding, grinding through a 180-mesh steel screen, adding a binder (terpineol containing 6 wt% of ethyl cellulose), and coating by a slurry coating methodCoating 0.0080g on a cathode-supported semi-electrolytic cell plate, and sintering at 1000 ℃ in a muffle furnace for 3h to obtain La_0.8Sr_0.2MnO_3-δ-YSZ oxygen electrode.

(3) Impregnating solution La_0.45Ce_0.55O_2-δPreparation of

Respectively preparing La with the molar concentration of 1mol/L³⁺、Ce³⁺The nitrate solution of (A) is accurately transferred and weighed with La according to the proportion of 9: 11³⁺、Ce³⁺In a 500ml beaker. Heating and stirring at 60 deg.C for 20min to obtain mixed La³⁺、Ce³⁺A nitrate solution of (a). Ammonium citrate (analytical grade) was then added: the total metal cation molar ratio was 1.3, the solution was stirred with heating, the pH of the solution was adjusted to 1 with nitric acid (analytical grade), the solution was made clear and transparent, the solution was fixed to volume in a 100ml volumetric flask, La_0.45Ce_0.55O_2-δThe concentration of (2) is 0.5 mol/L.

(4)LSM-YSZ-La_0.45Ce_0.55O_2-δOxygen electrode preparation

Using a microliter syringe, 4. mu.L of La prepared in step (3) was taken_0.45Ce_0.55O_2-δInjection of solution into La_0.8Sr_0.2MnO_3-δVacuum impregnation is carried out on the surface of a YSZ oxygen electrode, roasting is carried out for 3 hours at 800 ℃ to ensure that impregnation liquid enters the interior of an anode, the impregnation liquid is impregnated on the surface and the micropores of the oxygen electrode, and finally LSM-YSZ @ La is obtained_0.45Ce_0.55O_2-δAn oxygen electrode.

FIG. 3 shows LSM-YSZ @ La_0.45Ce_0.55O_2-δSEM image of oxygen electrode cross section of (1), as shown in FIG. 3, at LSM-YSZ @ La_0.45Ce_0.55O_2-δIn the oxygen electrode, La_0.45Ce_0.55O_2-δThe nanoparticles uniformly covered the surface of the LSM and YSZ particles.

Example 1:

(2)La_0.8Sr_0.2MnO_3-δPreparation of-YSZ oxygen electrode

Mixing La prepared in (1)_0.8Sr_0.2MnO_3-δAnode powder and YSZ powder (8% by mol of Y)₂O₃Stabilized ZrO₂(Tosho, Japan)) in a mass ratio of 3: 2, adding ethanol, grinding to mix uniformly, then placing the mixture under a baking lamp to dry the solvent, then transferring the mixture into a mortar to grind, grinding the ground mixture by a 180-mesh steel sieve, adding a binder (terpineol containing 6 wt% of ethyl cellulose), coating 0.0080g of the mixture on a cathode-supported half electrolytic cell sheet by a slurry coating method, and then placing the cathode-supported half electrolytic cell sheet in a muffle furnace to sinter the cathode-supported half electrolytic cell sheet for 3 hours at 1000 ℃ to obtain La_0.8Sr_0.2MnO_3-δ-YSZ oxygen electrode.

(3) Impregnation solution LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δPreparation of

Respectively prepared with a molar concentration of 1mol/L La³⁺、Ni²⁺、Fe³⁺、Ce³⁺The nitrate solution of La is accurately transferred and weighed according to the proportion of 145: 40: 60: 55³⁺、Ni²⁺、Fe³⁺、Ce³⁺In a 500ml beaker. Heating and stirring at 60 deg.C for 20min to obtain mixed La³⁺、Ni²⁺、Fe³⁺、Ce³⁺A nitrate solution of (a). Ammonium citrate (analytical grade) was then added: heating and stirring to total metal cation molar ratio of 1.3, adjusting pH of the solution to 1 with nitric acid (analytically pure) to make the solution clear and transparent, adding the solution to a 100ml volumetric flask, and adding LaNi_0.4Fe_0.6O_3-δThe concentration of (A) is 0.5mol/L, La_0.45Ce_0.55O_2-δThe concentration of (2) is 0.5 mol/L.

(4)LSM-YSZ-LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δOxygen electrode preparation

Taking 4 μ L of LaNi prepared in step 3 with a microliter syringe_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δInjection of solution into La_0.8Sr_0.2MnO_3-δdelta-YSZ oxygen electrode surface, vacuum impregnation, roasting at 800 ℃ for 3h to enable impregnation liquid to enter the anode, impregnating the impregnation liquid on the oxygen electrode surface and in the micropores, and finally obtaining LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δAn oxygen electrode.

FIG. 4 shows LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δSEM image of cross section of oxygen electrode, as shown in FIG. 4, at LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δIn the oxygen electrode, LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δThe nanoparticles uniformly covered the surface of the LSM and YSZ particles. From the statistics of the particle size, LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δThe average size of the nanoparticles was about 17 nm.

FIG. 5 shows LSM-YSZ, LSM-YSZ @ LaNi at 725 deg.C_0.4Fe_0.6O_3-δ、LSM-YSZ@La_0.45Ce_0.55O_2-δ、LSM-YSZ@LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δImpedance spectrum of (1). The difference between the high frequency intercept and the low frequency intercept in the graph represents the polarization resistance, and it can be seen that LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δThe polarization resistance of the material is obviously less than that of LSM-YSZ and LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ、LSM-YSZ@La_0.45Ce_0.55O_2-δExplanation of LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δHas higher battery performance.

FIG. 6 shows LSM-YSZ, LSM-YSZ @ LaNi at 800 deg.C_0.4Fe_0.6O_3-δ、LSM-YSZ@La_0.45Ce_0.55O_2-δ、LSM-YSZ@LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δVoltage-current density graph of (a). As can be seen, under the voltage of 1-3V, LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δHas a current density of 1.02A cm^-2Far higher than LSM-YSZ (0.474 Acm)^-2)、LSM-YSZ@LaNi₀.₄Fe_0.6O_3-δ(0.485Acm^-2)、LSM-YSZ@La_0.45Ce_0.55O_2-δ(0.478A cm^-2) Current density of (1), therefore LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δHas remarkable and excellent electrochemical performance.

Other examples compared with example 1, only LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe compositions of the compounds were varied and are detailed in the table below.

Serial number	LaA_xB_1-xO_3-δ	La_yC_1-yO_2-δ
			Example 2	LaNi_0.2Fe_0.8O_3-δ	La_0.7Ce_0.3O_2-δ
Example 3	LaCa_0.4Fe_0.6O_3-δ	La_0.8Pr_0.2O_2-δ

Example 2 modification of LaNi_xFe_1-xO_3-δ-La_yCe_1-yO_2-δThe element proportion in the composite is that the prepared electrode is LSM-YSZ @ LaNi_0.2Fe_0.8O_3-δ-La_0.7Ce_0.3O_2-δThe current density at 1.3V was 0.753A cm^-2Higher than LSM-YSZ (0.474 Acm)^-2)

Example 3 change LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe element category of the compound is that LSM-YSZ @ LaCa is prepared_0.4Fe_0.6O_3-δ-La_0.8Pr_0.2O_2-δElectrode with current density of 0.633A cm at 1.3V^-2Higher than LSM-YSZ (0.474 Acm)^-2)。

Comparative example 4

The only difference from example 1 is that LaNi_0.4Fe_0.6O_3-δAnd La_0.45Ce_0.55O_2-δIn a molar ratio of 3: 1, lower La is obtained_0.45Ce_0.55O_2-δImpregnation amount of LSM-YSZ @ LaNi_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δAnd an electrode. The current density of the electrode under the voltage of 1.3V is 0.528A cm^-2The same as LSM-YSZ @ LaNi in example 1_0.4Fe_0.6O_3-δ(0.485Acm^-2)、LSM-YSZ@La_0.45Ce_0.55O_2-δ(0.478A cm^-2) The current density of the alloy is relatively close to that of the LSM-YSZ @ LaNi in example 1_0.4Fe_0.6O_3-δ-La_0.45Ce_0.55O_2-δδ(1.02A cm^-2) A large difference indicates that the LaNi is_0.4Fe_0.6O_3-δAnd La_0.45Ce_0.55O_2-δThe impregnated electrode with the molar ratio of 3: 1 is not improved obviously, and the compound is in a proper molar ratio (LaNi in example 1)_0.4Fe_0.6O_2-δAnd La_0.45Ce_0.55O_2-δThe molar ratio of (1: 1) can effectively improve and improve the performance of the electrode battery.

From the comparative and examples, it can be seen that LSM-YSZ @ LaNi compares to the non-impregnated LSM or single component impregnated LSM electrode_0.4Fe_0.6O_2-δ-La_0.45Ce_0.55O_2-δHas significant performance advantages. The main reason is LaA_xB_1-xO_3-δAnd La_yC_1- _yO_2-δAdded together as active ingredients to produce a synergistic effect, LaA_xB_1-xO_3-δAnd La_yC_1-yO_2-δCan inhibit the coarsening of particles mutually, enhance the stability of the electrode and promote the oxygen electrodeAnd (4) performance. LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe nano particles will LaA_xB_1-xO_3-δAnd La_yC_1-yO_2-δMeanwhile, as an active component for impregnation, the catalyst has more surface oxygen vacancies and higher lattice oxygen mobility, and accelerates the oxygen evolution reaction in a steam electrolysis mode.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A solid oxide electrolysis cell oxygen electrode, wherein said oxygen electrode comprises an LSM-YSZ oxygen electrode and LaA_xB_1-xO_3-a-La_yC_1-yO_2-δA composite, said LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe composite is attached to the inner and outer surfaces of the LSM-YSZ oxygen electrode; wherein x is more than or equal to 0.1 and less than or equal to 0.9, y is more than or equal to 0.1 and less than or equal to 0.9, delta represents an oxygen deficiency value, and delta is more than or equal to 0 and less than or equal to 0.1;

the LaA_xB_1-xO_3-δThe A and B are respectively selected from one or more of Ce, Pr, Nd, Sm, Gd, Yb, Ni and Fe, and the A and B are different elements; the La_yC_1-yO_2-δC in the material is one or more of Ce, Mn, Nd, Bi, Gd, Yb, Ni and Fe; the LaA_xB_1- _xO_3-δ-La_yC_1-yO_2-δIn a composite, LaA_xB_1-xO_3-δAnd La_yC_1-yO_2-δThe molar ratio of (A) to (B) is 0.5-2: 1;

the LSM has a chemical formula of La_zSr_1-zMnO_3-δZ is more than or equal to 0.1 and less than or equal to 0.9; YSZ of the formula Y_mZr_1-mO₂，0.1≤m≤0.9。

2. A solid oxide electrolysis cell oxygen electrode as claimed in claim 1 wherein LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe average particle size of the nanoparticles of the composite is 10-50 nm; the molar ratio of the metal ions A to the metal ions B is 0.1-10: 1; the La_yC_1-yO_2-δThe molar ratio of the La and C metal ions is 0.1-10: 1.

3. The solid oxide electrolysis cell oxygen electrode of claim 1, wherein the thickness of the solid oxide electrolysis cell oxygen electrode is 20 to 60 μm; the LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δThe amount of the compound is 1 to 15 weight percent of the mass of the LSM-YSZ oxygen electrode.

4. A method of making a solid oxide electrolysis cell oxygen electrode according to any of claims 1 to 3, comprising the steps of:

s1, preparing an LSM-YSZ oxygen electrode;

s2, preparation LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δSolution: according to chemical formula LaA_xB_1-xO₃₄-La_yC_1-yO_2-δWeighing A, B, C soluble metal salt powder and lanthanum soluble metal salt powder, adding into water, adding complexing agent after dissolving, heating and stirring, and adjusting the pH of the solution to be less than or equal to 1 after dissolving;

s3, impregnation and roasting: and (4) dipping the LSM-YSZ oxygen electrode prepared in the step (S1) in the solution prepared in the step (S2), and roasting at 700-1000 ℃ for 3-4 h to obtain the solid oxide electrolytic cell oxygen electrode.

5. The method of claim 4, wherein in step S2, LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δMiddle LaA_xB_1-xO_3-δThe concentration of the solution is 0.1-2 mol/L, LaA_xB_1-xO_3-δ-La_yC_1-yO_2-δMiddle La_yC_1-yO_2-δThe concentration of the solution is 0.1-2 mol/L, the addition amount of the complexing agent is 0.5-2.7 times of the total metal ion molar amount, the complexing agent is any one of ammonium citrate, glycine, urea, EDTA and citric acid, the heating temperature is 60-90 ℃, and the stirring time is 2-10 hours; in step S3, the number of dipping times is 1-5.

6. The method for making a solid oxide electrolysis cell oxygen electrode according to claim 4, wherein said step S1 includes the steps of:

(1) preparing LSM anode powder:

a. according to the formula La of LSM_zSr_1-zMnO_3-δWeighing soluble metal salt powder of corresponding metal, adding water to dissolve the soluble metal salt powder, adding a complexing agent with the molar weight of 0.5-2.7 times of that of the total metal ions, heating and stirring at 60-90 ℃ for 15-20 min, and adjusting the pH of the solution to be less than or equal to 1 after dissolution; continuously evaporating at 60-90 ℃ until the solution becomes transparent gel liquid;

b. heating the gel-like substance at 200-500 ℃ for 10-30 min until self-propagating combustion is carried out to form fluffy powder, thus obtaining LSM primary powder;

c. calcining the primary powder at 700-1000 ℃ to form a phase, wherein the calcining time is 5-10 h, and grinding to obtain LSM secondary powder;

d. mixing the secondary powder with YSZ powder, adding a solvent, uniformly mixing, drying and grinding to obtain mixed powder; the solvent is one or more of ethanol, terpineol and n-butanol;

(2) preparing anode slurry: adding a binder into the mixed powder obtained in the step (1), fully grinding the mixed powder, and then coating the ground mixed powder on a cathode-supported semi-electrolytic cell sheet or an electrolyte-supported semi-electrolytic cell sheet for natural air drying to obtain a semi-electrolytic cell sheet;

(3) roasting: and (3) calcining the semi-electrolytic cell sheet obtained in the step (2) at 700-1000 ℃ for 3-5 h to obtain the LSM-YSZ oxygen electrode obtained in the step S1.

7. The method for preparing the oxygen electrode of the solid oxide electrolytic cell according to claim 6, wherein the mass ratio of the secondary powder to the YSZ powder is 1: 2-2: 1; the mass ratio of the mixed powder to the binder is 10: 1-2: 1; the binder is terpineol containing 6 wt% ethyl cellulose; the complexing agent is any one of ammonium citrate, glycine, urea, EDTA and citric acid.

8. The method of claim 6, wherein the cathode-supported half cell is made of a material selected from the group consisting of Ni-YSZ; in the electrolyte-supported half-cell plate, the material of the electrolyte supporting layer is YSZ.

9. The method of claim 6, wherein the cathode-supported half cell sheet or the electrolyte-supported half cell sheet is prepared by tape casting, calendaring, or powder dry pressing.

10. Use of an oxygen electrode according to any one of claims 1 to 3 in a solid oxide electrolysis cell.