CN106602136A - Barium zirconate-based electrolyte material system and preparation method thereof - Google Patents

Abstract

A barium zirconate-based electrolyte material system and a preparation method thereof belong to the field of solid oxide fuel cells. Electrolyte material system: BaZr _0.8 Gd _0.2‑x Zn _x O _3‑δ where x=0, 0.02, 0.04, 0.06; select proton conductor BaZrO ₃ as the electrolyte material system, doping _trivalent cation Y ³⁺ to improve the Proton conductivity, adding ZnO sintering aid, increasing its sintering ability, reducing the sintering temperature of the electrolyte material, so that the preparation of BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (x=0, 0.02, 0.04, 0.06) has Comprehensive properties of sintering activity, electrical conductivity, chemical stability and mechanical properties. Advantages: It can maintain good chemical stability, the micro-Vickers hardness can reach 719.58MPa, and the compressive strength can reach 29.68MPa.

Description

A kind of barium zirconate based electrolyte material system and preparation method thereof

technical field

The invention relates to a new proton-conductive electrolyte material system and a preparation method, belonging to the field of solid oxide fuel cells.

Background technique

Solid oxide fuel cells (SOFCs) have attracted extensive attention due to their advantages such as high energy conversion rate and low pollutant emission rate. According to the different conductive ions of its electrolyte, it can be divided into proton-conducting solid oxide fuel cell (H-SOFC) and ion-conducting solid oxide fuel cell (O-SOFC). For O-SOFC, the mass transfer process begins at the cathode. Oxygen dissociates and adsorbs under the catalysis of the cathode, and obtains electrons to form oxygen ions O ^2- , which pass through the dense electrolyte and anode fuel under the action of high oxygen partial pressure. The oxidation reaction generates H ₂ O or CO ₂ and releases electrons, and the electrons pass through the external circuit to form a current to drive the load to work; for H-SOFC, the mass transfer process starts at the anode, and the protons in the fuel are captured by the electron cloud of lattice oxygen to form And release electrons, driven by the tolerance electromotive force, protons reach the cathode side through the rotational transition between the electrolyte lattice oxygen, and react with the oxygen ions enriched on the cathode side to generate H ₂ O. Compared with O-SOFC, H-SOFC has the advantages of low conduction activation energy and high fuel utilization rate.

The proton conductor electrolyte material is mainly based on the BaCeO ₃ -BaZrO ₃ system, because of its higher ion conductivity and lower conduction activation energy than the oxygen ion conductor in the low temperature range. Although the BaCeO ₃ -based electrolyte has high proton conductivity, the conductivity of BZCY is 9×10 ^-3 S/cm at 500°C, but it is easy to generate CO ₂ and H ₂ O, and the chemical stability of the material is quite poor. Although the BaZrO ₃ -based electrolyte material has good inertness to CO ₂ and H ₂ O and relatively good grain conductivity, it has poor sintering activity. High temperature sintering at 1700°C leads to rapid grain growth and extremely low grain boundary conductivity. .

Contents of the invention

The object of the present invention is to provide a barium zirconate-based electrolyte material system and its preparation method, which can solve the problems _of high sintering temperature and low grain boundary resistance of BaZrO3.

The object of the present invention is achieved in this way: select proton conductor BaZrO3 as the electrolyte material system, dope _trivalent cation _Y3 ⁺ , improve the proton conductivity of BaZrO3, add ZnO sintering aid, increase its sintering ability, reduce the electrolyte material sintering temperature, so that the preparation of BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (x=0, 0.02, 0.04, 0.06) has comprehensive properties of sintering activity, electrical conductivity, chemical stability and mechanical properties.

The preparation method steps are:

1. The electrolyte powder to be produced in the present invention is BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06, and the required raw materials are calculated according to the molar mass of each element: C ₄ H Mass of ₆ BaO ₄ , Zr(NO ₃ ) ₄ 3H ₂ O, Gd(NO ₃ ) ₃ 6H ₂ O, ZnO;

2. Weigh the oxide ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O into a clean beaker, add 50-100ml of distilled water, add 10-15ml of nitric acid, heat, and stir until the solution is clear;

3. Weigh raw materials C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, and complexing agent citric acid, ethylenediaminetetraacetic acid (EDTA); the ratio of complexing agent is metal ion: citric acid: EDTA=1:1:0.8; After adding all four substances into the previous beaker, add 30-50ml of ammonia water, heat and stir until the solution is clear;

4. Heat the prepared clarified solution in an alumina ceramic pot, stir until the solution becomes viscous, and undergoes a violent self-combustion reaction. After cooling and collecting, this is the initial powder. Finally, put the initial powder into the Put it into a box-type furnace and pre-fire it at 1100°C for 3 hours to prepare the electrolyte powder.

Beneficial effects, due to the adoption of the above scheme, the use of Gd and Zn co-doping, the proton-type electrolyte material system BaZr _0.8 Gd _0.2-x Zn _x with excellent comprehensive properties such as sintering activity, chemical stability, electrical conductivity and mechanical properties O _3-δ where x=0, 0.02, 0.04, 0.06. After the pre-fired powder was pressed and formed, the samples were sintered at 1300°C, 1400°C, and 1500°C for 5 hours respectively. The relative density of BaZr _0.8 Gd _0.14 Zn _0.06 O _3-δ after sintering at 1400°C reached 89.12%, which can also be proved by SEM. in conclusion. After the sample was boiled in boiling water for 3 hours and treated in 100% _CO2 atmosphere at 700 °C for 10 h, it still maintained good chemical stability. BaZr _0.8 Gd _0.14 Zn _0.06 O _3-δ After the electrochemical performance test, it was found that the conductivity reached 2.5×10 ^-3 S/cm at 750°C. In addition, hardness and compressive strength tests were carried out, and the micro-Vickers hardness of BaZr _0.8 Gd _0.16 Zn _0.04 O _3-δ after sintering at 1500°C can reach 719.58MPa, and the compressive strength can reach 29.68MPa.

Advantages: It can maintain good chemical stability, the micro-Vickers hardness can reach 719.58MPa, and the compressive strength can reach 29.68MPa.

Description of drawings

Fig. 1 is the XRD diffraction pattern of Example 1-4BaZr _0.8 Gd _0.2-x Zn _x O _3-δ , where x=0, 0.02, 0.04, 0.06, after pre-calcination.

Figure 2 is Example 1-4BaZr _0.8 Gd _0.2-x Zn _x O _3-δ , where x=0, 0.02, 0.04, 0.06, after compression molding and sintering at 1300°C-5h, 1400°C-5h, 1500°C-5h The relative density curve.

Fig. 3 is the SEM image of Example 1-4 BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06, sintered at 1400°C for 5 hours after compression molding.

Fig. 4 is the XRD diffraction pattern of Example 1-4 BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06, the sample is treated with 100% CO2 for 10 hours.

Fig. 5 is a graph showing the variation of electrical conductivity with temperature in Example 1-4 BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06.

Fig. 6a is a diagram of micro-Vickers hardness values after sintering at different temperatures in Example 1-4 BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06.

Fig. 6b is a diagram of compressive strength values of Example 1-4BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06 after sintering at different temperatures.

detailed description

The invention includes a barium zirconate-based electrolyte material system and a preparation method of the barium zirconate-based electrolyte material system.

The proton conductor BaZrO ₃ is selected as the electrolyte material system, doped with trivalent cation Y ³⁺ to increase the proton conductivity of BaZrO ₃ , add ZnO sintering aid to increase its sintering ability, and reduce the sintering temperature of the electrolyte material, so that the preparation of BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (x=0, 0.02, 0.04, 0.06) has comprehensive properties of sintering activity, electrical conductivity, chemical stability and mechanical properties.

Described preparation method step is:

1. The electrolyte powder to be produced in the present invention is BaZr _0.8 Gd _0.2-x Zn _x O _3-δ where x=0, 0.02, 0.04, 0.06, and the required raw materials are calculated according to the molar mass of each element: C ₄ H Mass of ₆ BaO ₄ , Zr(NO ₃ ) ₄ 3H ₂ O, Gd(NO ₃ ) ₃ 6H ₂ O, ZnO;

2. Weigh the oxide ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O into a clean beaker, add 50-100ml of distilled water, add 10-15ml of nitric acid, heat, and stir until the solution is clear;

3. Weigh raw materials C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, and complexing agent citric acid, ethylenediaminetetraacetic acid (EDTA); the ratio of complexing agent is metal ion: citric acid: EDTA=1:1:0.8; After adding all four substances into the previous beaker, add 30-50ml of ammonia water, heat and stir until the solution is clear;

4. Heat the prepared clarified solution in an alumina ceramic pot, stir until the solution becomes viscous, and undergoes a violent self-combustion reaction. After cooling and collecting, this is the initial powder. Finally, put the initial powder into the Put it into a box-type furnace and pre-fire it at 1100°C for 3 hours to prepare the electrolyte powder.

Example 1. BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (BZG) electrolyte When x = 0, calculate the mass of the required raw material according to the molar mass of each element, after the calculation is completed, first weigh the oxide Put ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O in a clean beaker, add 50-100ml of distilled water, add 10-15ml of nitric acid, heat and stir until the solution is clear; then weigh C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, complexing agent citric acid and ethylenediaminetetraacetic acid (EDTA), after adding the four substances into the previous beaker, add 30-50ml of ammonia water, heat and stir until the solution is clear; Put the prepared clarified solution into an alumina ceramic pot, heat and stir until the solution becomes viscous and undergoes a violent self-combustion reaction, collect it after cooling, and this is the initial powder; finally put the initial powder into a box furnace Medium pre-calcination at 1100℃-3h to prepare electrolyte powder.

Example 2. BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (BZG-0.02Zn) electrolyte When x=0.02, calculate the mass of the required raw material according to the molar mass of each element, after the calculation is completed, first weigh Measure oxide ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O in a clean beaker, add 50-100ml distilled water, add 10-15ml nitric acid, heat, stir until the solution is clear; then weigh C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, complexing agent citric acid and ethylenediaminetetraacetic acid (EDTA), add all four substances to the previous beaker, add 30-50ml ammonia water, heat and stir until solution Clarification; heat and stir the prepared clarified solution in an alumina ceramic pot until the solution becomes viscous and undergoes a violent self-combustion reaction, collect after cooling, this is the initial powder; finally put the initial powder into Pre-fired in a box furnace at 1100°C for 3 hours to obtain electrolyte powder.

Example 3. BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (BZG-0.04Zn) electrolyte When x=0.04, calculate the mass of the required raw material according to the molar mass of each element. After the calculation is completed, first weigh Measure oxide ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O in a clean beaker, add 50-100ml distilled water, add 10-15ml nitric acid, heat, stir until the solution is clear; then weigh C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, complexing agent citric acid and ethylenediaminetetraacetic acid (EDTA), add all four substances to the previous beaker, add 30-50ml ammonia water, heat and stir until solution Clarification; heat and stir the prepared clarified solution in an alumina ceramic pot until the solution becomes viscous and undergoes a violent self-combustion reaction, collect after cooling, this is the initial powder; finally put the initial powder into Pre-fired in a box furnace at 1100°C for 3 hours to obtain electrolyte powder.

Example 4. BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (BZG-0.06Zn) electrolyte When x=0.06, calculate the mass of the required raw material according to the molar mass of each element, after the calculation is completed, first weigh Measure oxide ZnO and zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O in a clean beaker, add 50-100ml distilled water, add 10-15ml nitric acid, heat, stir until the solution is clear; then weigh C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, complexing agent citric acid and ethylenediaminetetraacetic acid (EDTA), add all four substances to the previous beaker, add 30-50ml ammonia water, heat and stir until solution Clarification; heat and stir the prepared clarified solution in an alumina ceramic pot until the solution becomes viscous and undergoes a violent self-combustion reaction, collect after cooling, this is the initial powder; finally put the initial powder into Pre-fired in a box furnace at 1100°C for 3 hours to obtain electrolyte powder.

Claims (2)

1. A barium zirconate-based electrolyte material system, characterized in that: select proton conductor BaZrO3 as electrolyte material system, doping _trivalent cation _Y3 ⁺ , improve the proton conductivity of BaZrO3, add ZnO sintering aid, increase Its sintering ability reduces the sintering temperature of the electrolyte material, so that the preparation of BaZr _0.8 Gd _0.2-x Zn _x O _3-δ (x=0, 0.02, 0.04, 0.06) has sintering activity, electrical conductivity, chemical stability and mechanical Comprehensive performance of performance. 2. the preparation method of a kind of barium zirconate base electrolyte material system described in claim 1 is characterized in that: the preparation method step is: (1), the electrolyte powder to be made in the present invention is BaZr _0.8 Gd _0.2-x Zn _x O _3-δ wherein x=0, 0.02, 0.04, 0.06, calculate the required raw material according to the molar mass of each element: C ₄ H ₆ BaO ₄ , Zr(NO ₃ ) ₄ 3H ₂ O, Gd(NO ₃ ) ₃ 6H ₂ O, ZnO mass; (2) Weigh the oxide ZnO and the zirconium compound Zr(NO ₃ ) ₄ 3H ₂ O in a clean beaker, add 50-100ml of distilled water, add 10-15ml of nitric acid, heat, and stir until the solution is clear; (3) Weigh raw materials C ₄ H ₆ BaO ₄ , Gd(NO ₃ ) ₃ 6H ₂ O, and complexing agent citric acid, ethylenediaminetetraacetic acid (EDTA); the ratio of complexing agent is metal ion: lemon Acid: EDTA=1:1:0.8; After adding all four substances into the previous beaker, add 30-50ml of ammonia water, heat, and stir until the solution is clear; (4) Put the prepared clarified solution into an alumina ceramic pot and heat it, stir until the solution becomes viscous and undergoes a violent self-combustion reaction. After cooling and collecting, this is the initial powder, and finally the initial powder The body was put into a box furnace and pre-fired at 1100°C for 3 hours to obtain an electrolyte powder.