Self-assembly air electrode material, preparation method and proton ceramic electrolytic tank

Abstract

The invention relates to a self-assembly air electrode material, a preparation method and a proton ceramic electrolytic tank, and belongs to the technical field of proton ceramic electrolytic tanks. The chemical formula of the material is PrBaCo2PxClxO5 + delta [Ba5 (PO4) 3Cl] y. The preparation method comprises the following steps: mixing water-soluble salts of praseodymium, barium and cobalt with ammonium dihydrogen phosphate and ammonium chloride according to a stoichiometric ratio, adding the mixture into water, adding glycine and a complexing agent, heating and stirring to obtain gel; and drying and calcining the gel to obtain the self-assembled air electrode material. Metal element doping is replaced by non-metal element phosphorus and chlorine self-assembly, so that the cost is reduced, and the problems of toxicity and environmental pollution are avoided; and the economical efficiency and environmental friendliness of the PCEC air electrode material in large-scale production are improved. In addition, through the design of the composite phase material, the electrochemical reaction is not limited to a three-phase interface, but can be expanded in the whole material body phase, so that the overall electrochemical performance and stability of the battery are improved.

Description

Technical Field

[0001] The invention relates to a self-assembled air electrode material, a preparation method and a proton ceramic electrolytic cell, belonging to the technical field of proton ceramic electrolytic cells. Background Art

[0002] Protonic Ceramic Electrolytic Cells (PCEC) are all-solid-state energy conversion devices that can generate green hydrogen by direct electrolysis of water. Its significant advantages include efficient energy conversion, wide fuel applicability, wide operating temperature range, and high-quality energy density. However, the low electrochemical activity and insufficient stability of the air electrode have become key challenges hindering the long-term efficient operation and commercial application of PCEC.

[0003] At present, most of the air in PCEC is La 0.8 Sr 0.2 Co 1-x Fe x O 3-δ (LSCF) and other perovskite oxides with mixed oxygen ion and electronic conductivity properties are used as electrocatalysts. However, the intrinsic proton conductivity of this type of perovskite material is very low, which makes the reaction active sites concentrated at the "air-air electrode-electrolyte" three-phase interface, thereby limiting the catalytic efficiency. On the other hand, the double perovskite oxide material PrBaCo2O 5+δ (PBC) is regarded as a new PCEC electrode material with great development potential due to its excellent electrochemical activity and structural stability in air. However, under complex application conditions, PBC still cannot fully meet the actual needs of PCEC.

[0004] At present, the double perovskite oxide material PrBaCo2O 5+δ(PBC)'s improvement strategies mainly focus on the doping of metal ions, which have the following two main drawbacks: 1. The cost and toxicity problems of metal element doping: In the development of proton ceramic electrolysis cells (PCEC), the doping of metal elements (such as cobalt doping, iron doping, cobalt-iron alloy doping, etc.) is commonly used to improve the electrochemical activity of materials. Although such doping can significantly improve the performance of the cells, especially in terms of conductivity and oxygen ion conductivity, metal elements, especially rare or precious metals (such as cobalt, platinum, etc.), are usually expensive, severely limiting large-scale production and application. In addition, some metal elements (such as cobalt, lead, cadmium, etc.) are not only toxic to the environment but may also release harmful substances during production and application, posing potential health risks. 2. Single-phase materials cannot extend the electrochemical reaction to the entire bulk phase: Although single-phase materials doped with metals can improve the electrochemical performance of materials, the electrochemical reactions of these materials are usually limited to the "triple-phase interface", that is, the contact area between gas, solid electrolyte, and catalyst. This limitation makes the efficiency of the electrochemical reaction unable to be extended throughout the bulk phase, resulting in limitations in the electrochemical activity and stability of the materials. Especially under high-temperature conditions, the reaction performance is prone to decline. Specifically, due to the limitations of the surface characteristics and lattice structure of single-phase materials, the conductivities of protons and oxygen ions are uneven and cannot be effectively propagated within the bulk phase, resulting in the reaction being limited to the triple-phase interface. This makes the overall performance of the cell unable to reach the ideal state and it is difficult to improve the power density and long-term stability of the cell. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a self-assembled air electrode material, a preparation method, and a proton ceramic electrolysis cell.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows.

[0007] A self-assembled air electrode material, the chemical formula of the material is PrBaCo2P x Cl x O 5+δ [Ba5(PO4)3Cl] y , where x = 0.075 - 0.125, y = 0.005 - 0.04, and δ represents oxygen vacancies.

[0008] Preferably, x = 0.09 - 0.11.

[0009] Preferably, y = 0.01 - 0.03.

[0010] The preparation method of a self-assembled air electrode material described in the present invention, the method steps include:

[0011] The water-soluble salts of praseodymium, barium and cobalt are mixed with ammonium dihydrogen phosphate and ammonium chloride according to the stoichiometric ratio, added to water, and glycine and a complexing agent are added. After heating and stirring, a gel is obtained; the gel is dried and calcined to obtain a self-assembled air electrode material.

[0012] Preferably, the complexing agent is citric acid.

[0013] Preferably, the dosage ratio of glycine, citric acid and the water-soluble salt of praseodymium is 900 - 1100 g: 900 - 1100 g: 1 mol.

[0014] Preferably, the gel is obtained by stirring at 80 - 90 °C for 10 - 14 h.

[0015] Preferably, it is dried at 240 - 260 °C for 2 - 2.5 h.

[0016] Preferably, it is calcined at 1050 - 1150 °C for 5 - 6 h.

[0017] A proton ceramic electrolytic cell, the cathode material of the electrolytic cell uses a self-assembled air electrode material described in the present invention.

[0018] Beneficial effects

[0019] In the present invention, non-metal elements phosphorus and chlorine are used for self-assembly to replace metal element doping, reducing costs and avoiding toxicity and environmental pollution problems; improving the economy and environmental friendliness of the PCEC air electrode material in large-scale production. In addition, through the design of the composite phase material, the electrochemical reaction is not limited to the three-phase interface, but can be carried out throughout the bulk of the material, thereby improving the overall electrochemical performance and stability of the battery. Description of the drawings

[0020] Figure 1 For PrBaCo2P in Example 1 0.1 Cl 0.1 O 5+δ [Ba5(PO4)3Cl] 0.1 X-ray diffraction characterization pattern.

[0021] Figure 2 Cross-sectional SEM image of the electrolytic cell NiO - BZCYYb||BZCYYb||PBCPCl - BPCl in Example 1.

[0022] Figure 3 Electrolytic I - V curve of the electrolytic cell NiO - BZCYYb||BZCYYb||PBCPCl - BPCl in Example 1.

[0023] Figure 4It is the galvanostatic electrolysis diagram of the electrolytic cell NiO-BZCYYb||BZCYYb||PBCPCl-BPCl in Example 1.

[0024] Figure 5 It is the X-ray diffraction characterization pattern of PrBaCo2P in Comparative Example 1 0.05 Cl 0.05 O 5+δ

[0025] Figure 6 It is the X-ray diffraction characterization pattern of PrBaCo2P in Comparative Example 2 0.2 Cl 0.2 O 5+δ Specific embodiments

[0026] The present invention will be further described in detail below in conjunction with specific examples and comparative examples.

[0027] Example 1

[0028] Take 4.3506 g of praseodymium nitrate, 3.6947 g of barium nitrate, 2.9107 g of cobalt nitrate, 0.1153 g of ammonium dihydrogen phosphate, 0.05349 g of ammonium chloride, 10 g of glycine, and 10 g of citric acid. After adding 500 ml of deionized water, stir at 80 °C in a water bath for 12 h to obtain a gel. Place the gel in a combustion oven and treat it at 250 °C for 2 h to obtain a precursor. Calcinate the precursor at 1100 °C for 5 h to obtain PrBaCo2P 0.1 Cl 0.1 O 5+δ [Ba5(PO4)3Cl] 0.02 (PBCPCl-BPCl) powder. XRD analysis shows that the material has a double-phase perovskite structure, as Figure 1 shown.

[0029] Using the above air electrode material as the cathode, using BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material as the electrolyte, and using the powder prepared from BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ material, NiO, and the binder polyethylene glycol as the fuel electrode, where δ is 0 to 0.4 and not 0, and NiO accounts for BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3-δ ​​30% to 70% of the total mass of the material and NiO (60% in this example), to prepare a proton ceramic electrolytic cell.

[0030] During operation, water vapor with 10 vol% H2O is introduced into the air electrode; 100 vol% hydrogen is pre-introduced into the fuel electrode and reduced at 750 °C for 2 h. After printing the air electrode on the electrolyte by screen printing, a PCEC monomer electrolytic cell is made by calcining at 1100 °C for 2 h, and its cross-sectional SEM is as Figure 2 shown.

[0031] The working principle of the proton ceramic electrolytic cell prepared with the air electrode material in the present invention is as follows: First, H2O is electrolyzed into H + and O2 at the air electrode, and H + is transferred to the fuel electrode through the electrolyte and undergoes electrochemical reduction to generate H2.

[0032] The electrolytic cell achieved an output of electrolytic current density of 1362 mA / cm 2 under the working conditions of 750 °C and 1.3 V, as Figure 3 . The battery stably operates at a current density of 1362 mA / cm 2 for 100 h under the working conditions of a working temperature of 750 °C and 1.3 V, as Figure 4 .

[0033] Comparative Example 1

[0034] In this comparative example, the dosages of ammonium dihydrogen phosphate and ammonium chloride are 0.0577 and 0.0267 g respectively, and the rest is the same as in Example 1. The XRD results ( Figure 5 ) show that P and Cl elements enter the perovskite lattice to form a single-phase material PrBaCo2P 0.05 Cl 0.05 O 5+δ , and a biphasic material containing Ba5(PO4)3Cl cannot be obtained.

[0035] Comparative Example 2

[0036] In this comparative example, the dosages of ammonium dihydrogen phosphate and ammonium chloride are 0.2306 and 0.1070 g respectively, and the rest is the same as in Example 1. The XRD results ( Figure 6 ) show that the proportions of P and Cl elements are too large to form a perovskite structure.

[0037] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention will be regarded as within the protection scope of the present invention.

Claims

1. A self-assembled air electrode material, characterized in that: The chemistry of the material is PrBaCo2P x Cl x O 5+δ [Ba5(PO4)3Cl] y , where x = 0.075 - 0.125, y = 0.005 - 0.04, and δ represents oxygen vacancies.

2. The self-assembled air electrode material according to claim 1, wherein: x＝0.09-0.11。 3. The self-assembled air electrode material according to claim 1, characterized in that: y＝0.01-0.03。 4. A method for preparing the self-assembled air electrode material according to any one of claims 1 to 3, characterized in that: The method steps include: Mix the water-soluble salts of praseodymium, barium and cobalt with ammonium dihydrogen phosphate and ammonium chloride according to the stoichiometric ratio, add them to water, and add glycine and a complexing agent, heat and stir to obtain a gel; dry and calcine the gel to obtain a self-assembled air electrode material.

5. The preparation method of a self-assembled air electrode material according to claim 4, characterized in that: The complexing agent is citric acid.

6. The preparation method of a self-assembled air electrode material according to claim 5, characterized in that: The dosage ratio of glycine, citric acid and the water-soluble salt of praseodymium is 900-1100g:900-1100g:1mol.

7. The preparation method of a self-assembled air electrode material according to claim 4, characterized in that: Stir at 80-90 °C for 10-14h to obtain a gel.

8. The preparation method of a self-assembled air electrode material according to claim 4, characterized in that: Dry at 240-260 °C for 2-2.5h.

9. The preparation method of a self-assembled air electrode material according to claim 4, characterized in that: Calcine at 1050-1150 °C for 5-6h.

10. A proton ceramic electrolytic cell, characterized in that: The cathode material of the electrolytic cell uses a self-assembled air electrode material described in any one of claims 1 to 3.

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