A b-site multi-element doped perovskite proton conductor electrolyte and a method of making the same

Abstract

The application discloses a B-site multi-element doped perovskite proton conductor electrolyte and a preparation method thereof. x Ce y Y z Gd m Sc n O 3‑δ , wherein δ is an oxygen vacancy concentration, 0

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell technology, specifically relating to a B-site multi-element doped perovskite proton conductor electrolyte and its preparation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs), as efficient and clean energy conversion devices, can directly convert chemical energy into electrical energy. Due to their core advantages such as wide fuel compatibility, high energy conversion efficiency, and environmental friendliness, they have shown good prospects for industrial application in multiple fields such as distributed power generation and transportation.

[0003] Proton ceramic fuel cells (PCFCs) have attracted widespread attention due to their lower operating temperature compared to traditional SOFCs. The proton conductor electrolyte is a core component of PCFCs and a key element affecting their performance and applications. An ideal proton conductor electrolyte must simultaneously satisfy high proton conductivity, excellent chemical stability (especially in atmospheres containing CO2 and H2O), and good sinterability. Currently, existing proton conductor electrolytes still fall short of fully meeting these requirements, necessitating the development of novel proton conductor electrolytes with superior performance. Summary of the Invention

[0004] The purpose of this invention is to provide a B-site multi-element doped perovskite proton conductor electrolyte and its preparation method. The prepared electrolyte has good chemical stability, optimized oxygen vacancy distribution, and improved proton conduction efficiency.

[0005] To achieve the above objectives, this invention proposes a B-site multi-element doped perovskite proton conductor electrolyte with the general chemical formula BaZr. x Ce y Y z Gd m Sc n O 3-δ , where δ is the oxygen vacancy concentration, 0<δ<0.4, 0.38≤x≤0.42, 0.18≤y≤0.22, 0.13≤z≤0.15, 0.12≤m≤0.14, 0.12≤n≤0.14, and x+y+z+m+n=1.

[0006] Preferably, the chemical formula is BaZr. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ .

[0007] This invention also proposes a method for preparing a B-site multi-element doped perovskite proton conductor electrolyte, comprising the following steps:

[0008] (1) Weigh out the metal precursors corresponding to Ba, Zr, Ce, Y, Gd and Sc according to the stoichiometric ratio of the electrolytes, and mix them by ball milling;

[0009] (2) The mixed precursor raw materials are dried and pre-sintered to obtain pre-sintered material;

[0010] (3) After crushing the pre-sintered material, add CuO and mix evenly;

[0011] (4) The electrolyte powder is calcined to obtain the calcined electrolyte material.

[0012] Preferably, the ball milling speed in step (1) is 300~400 rpm, the ball-to-material ratio is 10:1, and the ball milling time is 18~20 h.

[0013] Preferably, the drying temperature in step (2) is 80~100℃ and the drying time is 12~24 h; the pre-sintering temperature is 1300~1400℃ and the pre-sintering time is 10-12 h.

[0014] Preferably, the amount of CuO added in step (3) is 0.5~1.5wt%.

[0015] Preferably, the calcination heating rate in step (4) is 2~5℃ / min, the calcination temperature is 1400~1500℃, and the calcination time is 5~6 h.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] This invention enhances the performance of materials by fixing the optimized ratio of five elements (Zr, Ce, Y, Gd, and Sc) and utilizing their respective properties. Specifically, Zr improves the chemical stability of the material under a CO2 / H2O atmosphere; Ce improves the proton conductivity; and Y / Gd / Sc synergistically regulate the degree of lattice distortion, improve sintering performance, and optimize oxygen vacancy distribution to improve proton conduction efficiency.

[0018] The electrolyte prepared by this invention has good thermomechanical compatibility, high purity and density, and high proton conductivity. Attached Figure Description

[0019] Figure 1 This is the BaZr prepared in Example 1 of the present invention. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ XRD pattern of electrolyte material and perovskite crystal structure parameters;

[0020] Figure 2Here are SEM images of the electrolyte sheet prepared in Example 1 of this invention; where (A) is a surface morphology image of the electrolyte sheet; and (B) is a statistical distribution image of the grain size.

[0021] Figure 3 Thermal shrinkage curve of the electrolyte prepared in Example 1 of this invention within the sintering range of 20~1450℃;

[0022] Figure 4 AC impedance spectra of the electrolyte material prepared in Example 1 of this invention in humid air at 200-700℃;

[0023] Figure 5. Arrhenius fitting curve of proton conductivity of the electrolyte material prepared in Example 1 of the present invention in humid air / hydrogen at 400-700℃;

[0024] Figure 6 Stability test of the electrolyte material prepared in Example 1 of the present invention at 600°C and 30% CO2 atmosphere;

[0025] Figure 7 The stability of the electrolyte material prepared in Example 1 of this invention was tested at 600°C in a 50% water vapor atmosphere.

[0026] Figure 8 XRD pattern of the electrolyte material prepared in Example 1 of this invention after treatment with 50% water vapor and 30% CO2 at 600℃;

[0027] Figure 9 Cross-sectional SEM image of the electrolyte material prepared in Example 1 of this invention applied to a full cell;

[0028] Figure 10 The electrolyte material prepared in Example 1 of this invention is used in the full-cell power generation performance test diagram;

[0029] Figure 11 Cross-sectional SEM image of the electrolyte material prepared in Example 1 of this invention applied to a double-layer electrolyte full cell;

[0030] Figure 12 The electrolyte material prepared in Example 1 of this invention is used in a long-term water electrolysis stability test of a double-layer electrolyte full cell. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] Example 1: A method for preparing a B-site multi-element doped perovskite proton conductor electrolyte

[0033] (1) According to the chemical formula BaZr 0.4 Ce 0.2 Y0.14 Gd 0.13 Sc 0.13 O 3-δ Weigh BaCO3, ZrO2, CeO2, Y2O3, Gd2O3 and Sc2O3 with a purity of 99.9% or higher, and mix them using a planetary ball mill with zirconia grinding balls at a speed of 300~400 rpm, a ball-to-material ratio of 10:1 and a ball milling time of 20 h.

[0034] (2) After drying the mixed precursor raw materials in a forced-air dryer at 80~100℃ for 12~24h, the temperature is raised to 1350℃ at a heating rate of 5℃ / min for pre-calcination, held for 10h, and then cooled with the furnace to obtain the pre-sintered material.

[0035] (3) After crushing the pre-sintered material, add 1wt% CuO (analytical grade) and mix evenly to obtain electrolyte powder;

[0036] (4) Press the green blanks into round green blanks with a diameter of 10-20 mm and a thickness of 1-2 mm under a pressure of 300 MPa for 2-5 min. Heat the green blanks to 1450℃ at a heating rate of 2-5℃ / min, hold for 5 h, and cool to room temperature with the furnace at 5℃ / min to obtain the calcined electrolyte sheet.

[0037] Systematic characterization of the electrolyte sheet obtained in Example 1

[0038] Phase analysis: XRD refinement ( Figure 1 The absence of impurity peaks in the chromatogram indicates that the material has a pure perovskite structure without impurities. The cell parameter diagram shows a moderate degree of lattice distortion, which is beneficial for proton conduction. The relative density of 95% was measured using the Archimedes displacement method (with deionized water as the test medium), ensuring excellent mechanical strength and gas barrier properties, effectively preventing cross-permeation of fuel gas and air.

[0039] Density: The electrolyte sheet surface is dense and free of pores, with distinct grain boundaries. Statistical analysis shows that the average grain size is 12.2 μm. Figure 2 ).

[0040] Sintering behavior: The electrolyte sheet prepared in Example 1 was sintered in the range of 20~1450℃. The thermal shrinkage curve was smooth without any abrupt changes. The linear shrinkage rate of sintering was measured to be 19.5%, which is consistent with the thermal expansion coefficient of commonly used electrode materials. This is beneficial for battery integration and long-term cycle stability, indicating that the sintering behavior of the material is stable.

[0041] Conductivity: The EIS (electrochemical impedance spectroscopy) of the electrolyte material prepared in Example 1 was tested in humid air at 200-700℃. Figure 4 ), and fit the Arrhenius plot ( Figure 5The results show that the conductivity is 25 mS / cm and the activation energy is 0.66 eV in humid air at 700℃, which conforms to the proton conduction mechanism and is suitable for medium and low temperature operation.

[0042] Chemical stability: Resistant to 30% CO2 at 600℃ Figure 6 ) and 50% H2O ( Figure 7 Treat in an atmosphere for 500 h. Figure 6 and Figure 7 All results indicate that the electrolyte's ohmic resistance is stable, and the calculated conductivity decay is less than 3%. XRD analysis after placing the electrolyte in the above environment for 50 hours showed no other impurity phases formed, indicating a stable crystal structure. Figure 8 This demonstrates its good stability under 50% H2O and 30% CO2 atmospheres.

[0043] Example 2

[0044] This embodiment provides a method for preparing a fuel electrode supported full cell, which includes a fuel electrode support, a functional layer, an electrolyte layer, and an air electrode material.

[0045] The fabrication process of a fuel electrode supported full cell includes the following steps:

[0046] (1) The electrolyte powder prepared in Example 1 before calcination was mixed with NiO, graphite pore-forming agent and PVB binder in a mass ratio of 50:38:10:2, ball-milled at 400 rpm for 10 h, and after drying, the powder was placed in a circular pressure mold and held under pressure at 300 MPa for 2 min to obtain the fuel electrode support.

[0047] (2) Prepare a functional layer slurry by mixing the electrolyte powder and NiO prepared in Example 1 before calcination. The functional layer slurry consists of: 10wt% electrolyte powder, 10wt% NiO, 70wt% terpineol, 8wt% ethyl cellulose, and 2wt% triethanolamine, totaling 100wt%.

[0048] (3) Prepare BaZr by mixing the electrolyte powder prepared in Example 1 before calcination with terpineol organic solvent, ethyl cellulose binder, and triethanolamine defoamer in proportions of 20 wt%, 70 wt%, 8 wt%, and 2 wt%, respectively. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ Electrolyte impregnation slurry.

[0049] (4) The functional layer slurry is impregnated on the surface of the fuel electrode support pressed in step (1) by a pull-impregnation method to obtain a support-functional layer composite preform. The pull-up rate is 5~10 mm / s, the number of impregnations is 2~5, and the preform is dried at 80℃ for 30 min after each impregnation. The composite preform is then calcined at 800℃ in air for 180 min to remove organic matter from the composite preform.

[0050] (5) The calcined support-functional layer composite preform is impregnated with BaZr using the same method as in step (4) above. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ Electrolyte slurry was used to obtain an electrolyte composite preform. The electrolyte composite preform was sintered at 1450℃ for 5 h to obtain a dense electrolyte half-cell.

[0051] (6) Grind one side of the half-cell covered with electrolyte on both sides, and screen print air electrode paste onto the electrolyte surface on the other side. Air electrode paste composition: 20 wt% electrolyte powder prepared in Example 1 before calcination, PrBaCo2O 5+δ 30 wt%, terpineol 45 wt%, ethyl cellulose 5 wt%. The mixture was calcined again at 950℃ in air for 180 min, and after cooling, a full cell consisting of a fuel electrode, functional layer, electrolyte, and air electrode was obtained.

[0052] Full cell testing: Full cell cross-sectional SEM ( Figure 9 The electrolyte layer is dense and non-porous, and is tightly bonded to the electrode layer.

[0053] Tests show that the battery exhibits a high open-circuit voltage (1V) and power output (0.5W) at 650℃. Figure 10 This demonstrates the practical feasibility of the electrolyte material.

[0054] Example 3

[0055] This embodiment provides a method for preparing a fuel electrode supported bilayer electrolyte full cell, which includes a fuel electrode support, a functional layer, a bilayer electrolyte, and an air electrode material.

[0056] The fabrication process of a fuel electrode-supported bilayer electrolyte full cell includes the following steps:

[0057] (1) The electrolyte powder prepared in Example 1 before calcination was mixed with NiO, graphite pore-forming agent and PVB binder in a mass ratio of 50:38:10:2, ball-milled at 400 rpm for 10 h, and after drying, the powder was placed in a circular pressure mold and held at 300 MPa for 2 min to obtain the fuel electrode support.

[0058] (2) Prepare a functional layer slurry by mixing the electrolyte powder and NiO prepared in Example 1 before calcination. The functional layer slurry consists of: 10wt% electrolyte powder from Example 1, 10wt% NiO, 70wt% terpineol, 8wt% ethyl cellulose, and 2wt% triethanolamine, totaling 100wt%.

[0059] (3) BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ BaZr was formulated with terpineol organic solvent, ethyl cellulose binder, and triethanolamine defoamer in proportions of 20 wt%, 70 wt%, 8 wt%, and 2 wt%, respectively. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ Electrolyte impregnation slurry.

[0060] (4) Prepare BaZr by mixing the electrolyte powder prepared in Example 1 before calcination with terpineol organic solvent, ethyl cellulose binder and triethanolamine defoamer in proportions of 20 wt%, 70 wt%, 8 wt% and 2 wt%, respectively. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ Electrolyte impregnation slurry.

[0061] (5) The functional layer slurry is impregnated on the surface of the fuel electrode support pressed in step (1) by a pull-impregnation method to obtain a support-functional layer composite preform. The pull-up rate is 5~10 mm / s, the number of impregnations is 2~5, and the preform is dried at 80℃ for 30 min after each impregnation. The composite preform is then calcined at 800℃ in air atmosphere for 180 min to remove organic matter from the composite preform.

[0062] (6) The calcined support-functional layer composite preform is impregnated with BaZr using the same method as in step (5) above. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ Electrolyte layer slurry is used to obtain a single-layer electrolyte composite preform.

[0063] (7) The single-layer electrolyte composite preform is impregnated with BaZr using the same method as in operation (4) above. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13O 3-δ Electrolyte layer slurry was used to obtain a double-layer electrolyte composite preform. The electrolyte composite preform was sintered at 1450℃ for 5 h to obtain a dense electrolyte half-cell.

[0064] (8) Polish one side of the half-cell with double-layer electrolyte on both sides, and screen print air electrode paste onto the surface of the other side of the double-layer electrolyte. The air electrode material is composed of electrolyte powder prepared in Example 1 before calcination and La. 0.8 Sr 0.2 Co 0.2 Fe 0.8 O 3-δ It was composed of terpineol and ethyl cellulose in proportions of 20 wt%, 30 wt%, 45 wt%, and 5 wt%. After calcination again at 1000℃ in air for 180 min, and cooling, a "fuel electrode | functional layer | (BaZr)" was obtained. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ -BaZr 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ A full cell consisting of a double-layer electrolyte and an air electrode.

[0065] Full cell testing: Full cell cross-sectional SEM ( Figure 11 The results show that the electrolyte layer is dense and non-porous, the bilayer electrolyte does not separate into layers, and it is tightly bonded to the electrode layer.

[0066] Tests show that at 600℃, 0.4 A / cm 2 The electrolyte operated stably for 600 hours at the electrolysis current density, proving its practical feasibility as a dual electrolyte protective layer.

[0067] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A perovskite proton conductor electrolyte with multi-element doping at the B site, characterized in that, The general chemical formula is BaZr. x Ce y Y z Gd m Sc n O 3-δ , where δ is the oxygen vacancy concentration, 0<δ<0.4, 0.38≤x≤0.42, 0.18≤y≤0.22, 0.13≤z≤0.15, 0.12≤m≤0.14, 0.12≤n≤0.14, and x+y+z+m+n=1.

2. A perovskite proton conductor electrolyte with multi-element doping at the B site, characterized in that, The chemical formula is BaZr. 0.4 Ce 0.2 Y 0.14 Gd 0.13 Sc 0.13 O 3-δ .

3. A method for preparing a B-site multi-element doped perovskite proton conductor electrolyte as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Weigh out the metal precursors corresponding to Ba, Zr, Ce, Y, Gd and Sc according to the stoichiometric ratio of the electrolytes, and mix them by ball milling; (2) The mixed precursor raw materials are dried and pre-sintered to obtain pre-sintered material; (3) After crushing the pre-sintered material, add CuO and mix evenly to obtain electrolyte powder; (4) The electrolyte powder is calcined to obtain the calcined electrolyte material.

4. The preparation method according to claim 3, characterized in that, In step (1), the ball milling speed is 300~400 rpm, the ball-to-material ratio is 10:1, and the ball milling time is 18~20h.

5. The preparation method according to claim 3, characterized in that, The drying temperature in step (2) is 80~100℃ and the drying time is 12~24h; the pre-sintering temperature is 1300~1400℃ and the pre-sintering time is 10-12h.

6. The preparation method according to claim 3, characterized in that, The amount of CuO added in step (3) is 0.5~1.5wt%.

7. The preparation method according to claim 3, characterized in that, The calcination heating rate in step (4) is 2~5℃ / min, the calcination temperature is 1400~1500℃, and the calcination time is 5~6 h.

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