Three-phase conduction air electrode material, preparation method thereof, fuel cell and electrode thereof

Abstract

The invention provides a three-phase conduction air electrode material and a preparation method thereof, a fuel cell and an electrode thereof, relates to the technical field of fuel cells, and aims to solve the technical problem of low catalytic activity of an air electrode at medium and low temperatures. According to the preparation method of the three-phase conduction air electrode material provided by the invention, praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate are used as raw materials, so that the oxygen vacancy concentration of a system can be improved by introducing a low-valence potassium element into an A site in a PrNi0. 5Co0. 5O3 perovskite structure of the air electrode material; the oxygen reduction reaction catalytic activity of the proton ceramic fuel cell is improved. On the other hand, in-situ precipitation of B-site element nickel is induced through defect regulation and control on the A site, the oxygen surface exchange and bulk phase diffusion rate of the electrode material is increased, and the catalytic activity of the oxygen reduction reaction is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and more particularly, to a three-phase conducting air electrode material and a preparation method thereof, a fuel cell and an electrode thereof. Background Art

[0002] Solid oxide cells are considered to be efficient and clean energy conversion and storage technologies due to their good reversible operation flexibility in fuel cell and electrolytic cell modes. A central goal of current solid oxide cell research is to reduce the operating temperature to medium and low temperatures (500 °C to 700 °C) to improve thermal cycle tolerance, promote dynamic response, and reduce system costs. In particular, reversible proton ceramic electrochemical cells operating at low temperatures have received extensive attention in recent years due to their excellent performance (low activation energy for proton transport) and the production of pure and dry hydrogen in the electrolysis mode.

[0003] In order to make reversible proton ceramic electrochemical cells commercially competitive in medium and low temperature environments, it is urgent to develop air electrodes with high catalytic activity and stability. However, the kinetics of the oxygen evolution reaction and oxygen reduction reaction on the air electrode decrease exponentially with the decrease of the operating temperature, and the polarization resistance of the reversible proton ceramic electrochemical cell increases significantly.

[0004] The oxygen electrode of a high-performance proton ceramic fuel cell should have excellent oxygen reduction reaction activity, high proton / oxygen ion / electron conductivity, and sufficient stability. Therefore, it is necessary to finely adjust the bulk and surface properties of the electrode material. At present, surface modification has been widely explored to improve the air electrode performance of high-performance proton ceramic fuel cells by enhancing surface reaction kinetics. Impregnating nanoparticles on the cathode surface is beneficial to improving the oxygen reduction reaction activity of the cathode material of high-performance proton ceramic fuel cells.

[0005] In addition, the precipitation of cations in the perovskite (PrNi 0.5 Co 0.5 O3) lattice can combine with oxygen elements to obtain perovskite oxides, and these perovskite oxides have been used to manufacture nanoparticles for various catalytic / electrocatalytic applications. In the actual treatment process, surface modification of perovskite by precipitating perovskite oxide nanoparticles with reducing gases can effectively improve electrochemical anodic oxidation, but these perovskite oxide nanoparticles are easily recombined into the perovskite lattice, resulting in unstable catalytic performance of the finally prepared battery.

[0006] Therefore, it is an urgent technical problem to invent an air electrode with high catalytic activity even at medium and low temperatures. Summary of the Invention

[0007] In view of this, the present invention aims to solve the technical problem of low catalytic activity of air electrodes at medium and low temperatures.

[0008] The first aspect of the present invention provides a method for preparing a three-phase conducting air electrode material.

[0009] The second aspect of the present invention provides a three-phase conducting air electrode material.

[0010] The third aspect of the present invention provides a fuel cell electrode.

[0011] The fourth aspect of the present invention provides a fuel cell.

[0012] Specifically, the present invention is achieved through the following technical solutions:

[0013] The technical solution of the first aspect of the present invention provides a method for preparing a three-phase conducting air electrode material, including: preparing a three-phase conducting air electrode material from praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate.

[0014] In some technical solutions, optionally, the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is (0.5 - 1.5):(0.2 - 0.8):(0.2 - 0.8):(0.05 - 0.25).

[0015] In some technical solutions, optionally, the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is (0.8 - 1.2):(0.3 - 0.7):(0.3 - 0.7):(0.1 - 0.2).

[0016] In some technical solutions, optionally, the step of preparing a three-phase conducting air electrode material from praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate specifically includes: dissolving praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate in a solvent, adding a dispersant and a complexing agent to obtain a mixed solution; adding an alkaline solution to the mixed solution to adjust the pH value of the mixed solution to a first preset value and heating the mixed solution to a first preset temperature to make the mixed solution into a viscous gel; drying the viscous gel to obtain a precursor powder of the three-phase conducting air electrode material; sintering the precursor powder at a second preset temperature to obtain the three-phase conducting air electrode material.

[0017] In some technical solutions, optionally, the alkaline solution includes ammonia water.

[0018] In some technical solutions, optionally, the first preset value is greater than 7 and less than or equal to 9.

[0019] In some technical solutions, optionally, the first preset temperature is greater than or equal to 80 °C and less than or equal to 90 °C.

[0020] In some technical solutions, optionally, the second preset temperature is greater than or equal to 800 °C and less than or equal to 1200 °C.

[0021] In some technical solutions, optionally, the dispersant includes ethylenediaminetetraacetic acid, and the complexing agent includes citric acid.

[0022] In some technical solutions, optionally, the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions is (0.8 - 1.2):(0.8 - 1.2):(1.8 - 2.2), and the molar mass of the metal ions is equal to the sum of the molar masses of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate.

[0023] In some technical solutions, optionally, the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions is 1:1:2.

[0024] In some technical solutions, optionally, the solvent includes deionized water.

[0025] The second aspect of the present invention provides a three-phase conducting air electrode material, which is prepared according to the preparation method of the three-phase conducting air electrode material of any one of the technical solutions in the first aspect of the present invention.

[0026] The third aspect of the present invention provides a fuel cell electrode, which is prepared by the three-phase conducting air electrode material of the technical solution in the second aspect of the present invention.

[0027] The fourth aspect of the present invention provides a fuel cell, including the fuel cell electrode of the technical solution in the third aspect of the present invention.

[0028] In some technical solutions, optionally, the fuel cell is prepared by the following method: grinding nickel nitrate, BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ and starch in ethanol to obtain a slurry, grinding the slurry in a mortar to obtain a dry fuel electrode powder, pressing the fuel electrode powder under a first preset pressure to form a fuel electrode green body; laying the BZCYYb electrolyte powder flat on the fuel electrode green body and co-pressing under a second preset pressure to obtain a half-cell green body, calcining the half-cell green body at a third preset temperature to obtain a half-cell; adding the three-phase conducting air electrode material to an alcohol solution and grinding to obtain an air electrode slurry; spraying the air electrode slurry on one side surface of the BZCYYb electrolyte powder of the half-cell, and then calcining the half-cell after spraying the air electrode slurry at a fourth preset temperature to obtain a fuel cell.

[0029] In some technical solutions, optionally, the ethanol is anhydrous ethanol.

[0030] In some technical solutions, optionally, the first preset pressure is greater than or equal to 50 Mpa and less than or equal to 70 Mpa; the second preset pressure is greater than or equal to 140 Mpa and less than or equal to 160 Mpa; the third preset temperature is greater than or equal to 1400 °C and less than or equal to 1500 °C; the fourth preset temperature is greater than or equal to 900 °C and less than or equal to 1000 °C.

[0031] In some technical solutions, optionally, the alcohol solution includes ethylene glycol, isopropyl alcohol, and glycerol.

[0032] In some technical solutions, optionally, the volume ratio of ethylene glycol, isopropyl alcohol, and glycerol is (1 - 3):(8 - 12):(0.5 - 1.5).

[0033] In addition, the present invention also provides an application of a three - phase conducting air electrode material in a fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or related technologies. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0036] Figure 1 It is a schematic preparation flow diagram of the preparation method of the three - phase conducting air electrode material provided in the embodiment of the present invention;

[0037] Figure 2 It is an XRD diagram of the phase structure of KPNC provided in the embodiment of the present invention;

[0038] Figure 3 It is an XRD diagram of the phase structure of PNC provided in the comparative example of the present invention;

[0039] Figure 4 It is an XRD diagram of the phase structure of PNC0.9 provided in the comparative example of the present invention;

[0040] Figure 5 It is an XRD diagram of the phase structure of KPNC55 provided in the comparative example of the present invention;

[0041] Figure 6 It is an EIS diagram of the KPNC full cell provided in the embodiment of the present invention;

[0042] Figure 7The I-V-P diagram of the KPNC full cell provided by the embodiment of the present invention;

[0043] Figure 8 The EIS diagram of the PNC full cell provided by the embodiment of the present invention;

[0044] Figure 9 The I-V-P diagram of the PNC full cell provided by the embodiment of the present invention;

[0045] Figure 10 The schematic block diagram of the fuel cell provided by the embodiment of the present invention.

[0046] Among them, Figure 10 The corresponding relationship between the component names and labels is as follows:

[0047] 1 fuel cell, 12 fuel cell electrodes. Specific implementation manners

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1

[0050] This embodiment provides a preparation method of a fuel cell, including the following steps:

[0051] Step 1, preparation of an air electrode material: According to the chemical formula Pr 0.9 K 0.1 Ni 0.5 Co 0.5 O 3-δWeigh potassium nitrate, praseodymium nitrate, cobalt nitrate, and nickel nitrate in corresponding stoichiometric ratios (where 0.9 mol of praseodymium nitrate, 0.1 mol of potassium nitrate, 0.5 mol of cobalt nitrate, and 0.5 mol of nickel nitrate). Add them to a beaker containing an appropriate amount of deionized water, stir using a magnetic stirrer, and heat until the solution is completely dissolved. According to the molar ratio ethylenediaminetetraacetic acid:citric acid:metal ions = 1:1:2, weigh ethylenediaminetetraacetic acid and citric acid and add them to the above nitrate solution. Then continue to add ammonia water to adjust the pH to weakly alkaline (pH = 8), continue stirring, with the stirring temperature at 85 °C, and stir until the solution becomes a viscous colloid. Put the viscous colloid into a drying oven to dry and obtain a fluffy precursor powder. Put the fluffy precursor powder into a crucible, place it in a muffle furnace, and sinter at 1000 °C for 5 hours to obtain the target powder, denoted as KPNC (where K represents potassium element, P represents praseodymium element, N represents nickel element, and C represents cobalt element; the same applies to PNC below). Among them, the XRD pattern of the phase structure of KPNC is as shown in Figure 2 shown.

[0052] Step 2. Preparation of the fuel electrode: Weigh 6.5 g of NiO and 3.5 g of BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ , and 1 g of soluble starch, and ball-mill them in absolute ethanol for 2 h. Collect the ball-milled slurry, place it in a mortar, and manually grind it to obtain a dry powder, which is the fuel electrode powder;

[0053] Step 3. Preparation of the half-cell: Weigh 0.35 g of the fuel electrode powder, press it into a green body under a pressure of 60 Mpa, obtain a fuel electrode green body. Weigh 0.15 g of the ball-milled BZCYYb electrolyte powder, spread it evenly on the fuel electrode green body, and co-press it into a shape under a pressure of 150 Mpa. Calcinate the co-pressed green body at 1450 °C for 10 h to obtain a half-cell;

[0054] Step 4. Preparation of the air electrode slurry: Weigh 1 g of the air electrode material KPNC powder, add 2 ml of ethylene glycol, 10 ml of isopropyl alcohol, and 1 ml of glycerol, and ball-mill them in a ball-milling tank for 1 h to obtain the air electrode slurry;

[0055] Step 5. Preparation of the full cell: Spray the air electrode slurry on the electrolyte surface of the half-cell, then transfer the cell to a muffle furnace, and calcinate it at 950 °C for 4 h to obtain a solid oxide single cell, denoted as the KPNC full cell. Among them, the EIS diagram (electrochemical impedance diagram) of the KPNC full cell is as shown in Figure 6 shown, and the I-V-P diagram (current density-voltage-power density diagram) of the KPNC full cell is as shown in Figure 7 shown.

[0056] Comparative Example 1

[0057] This comparative example provides a method for preparing a fuel cell, which includes the following steps:

[0058] Step 1. Preparation of the air electrode material: According to the chemical formula PrNi 0.5 Co 0.5 O 3-δ Weigh corresponding stoichiometric ratios of praseodymium nitrate, cobalt nitrate, and nickel nitrate (where 1 mol of praseodymium nitrate, 0.5 mol of cobalt nitrate, and 0.5 mol of nickel nitrate), add them to a beaker containing an appropriate amount of deionized water, stir using a magnetic stirrer, and heat until the solution is completely dissolved. According to the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions = 1:1:2, weigh ethylenediaminetetraacetic acid and citric acid and add them to the above nitrate solution. Then continue to add ammonia water to adjust the pH to weakly alkaline (pH = 8), continue stirring, with the stirring temperature at 85 °C, stir until the solution becomes a viscous colloid. Put the viscous colloid into a drying oven to dry, obtaining a fluffy precursor powder. Put the fluffy precursor powder into a crucible, place it in a muffle furnace and sinter at 1000 °C for 5 hours to obtain the target powder, denoted as PNC. Among them, the XRD pattern of the phase structure of PNC is as Figure 3 shown.

[0059] Step 2. Preparation of the fuel electrode: Weigh 6.5 g of NiO, 3.5 g of BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ , and 1 g of soluble starch, ball mill in absolute ethanol for 2 h, collect the ball-milled slurry and manually grind it in a mortar to obtain a dry powder, which is the fuel electrode powder;

[0060] Step 3. Preparation of the half-cell: Weigh 0.35 g of the fuel electrode powder, press it into a green body under a pressure of 60 Mpa to obtain a fuel electrode green body. Weigh 0.15 g of the ball-milled BZCYYb electrolyte powder and spread it evenly on the fuel electrode green body, and co-press it into a green body under a pressure of 150 Mpa. Calcinate the co-pressed green body at 1450 °C for 10 h to obtain a half-cell;

[0061] Step 4. Preparation of the air electrode slurry: Weigh 1 g of the air electrode material PNC powder, add 2 ml of ethylene glycol, 10 ml of isopropyl alcohol, and 1 ml of glycerol to a ball mill jar and ball mill for 1 h to obtain the air electrode slurry;

[0062] Step 5. Preparation of the full cell: Spray the air electrode slurry on the electrolyte surface of the half-cell, and then transfer the cell to a muffle furnace and calcine it at 950 °C for 4 h to obtain a solid oxide single cell, denoted as the PNC full cell. Among them, the EIS diagram of the PNC full cell is as Figure 8As shown, the I-V-P diagram of the PNC full cell is as Figure 9 shown.

[0063] Comparative Example 2

[0064] This comparative example provides a method for preparing a fuel cell, including the following steps:

[0065] Step 1, preparation of air electrode material: According to the chemical formula Pr 0.9 Ni 0.5 Co 0.5 O 3-δ Weigh corresponding stoichiometric ratios of praseodymium nitrate, cobalt nitrate, and nickel nitrate (where 0.9 mol of praseodymium nitrate, 0.5 mol of cobalt nitrate, and 0.5 mol of nickel nitrate), add them to a beaker containing an appropriate amount of deionized water, stir using a magnetic stirrer, and heat until the solution is completely dissolved. According to the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions = 1:1:2, weigh ethylenediaminetetraacetic acid and citric acid and add them to the above nitrate solution. Then continue to add ammonia water to adjust the pH to weakly alkaline (pH = 8), continue stirring, with the stirring temperature at 85 °C, stir until the solution becomes a viscous colloid. Put the viscous colloid into an oven to dry, obtain a fluffy precursor powder, put the fluffy precursor powder into a crucible, place it in a muffle furnace and sinter at 1000 °C for 5 hours to obtain the target powder, denoted as PNC0.9. Among them, the XRD diagram of the phase structure of PNC0.9 is as Figure 4 shown.

[0066] Step 2, preparation of fuel electrode: Weigh 6.5 g of NiO, 3.5 g of BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ , and 1 g of soluble starch, ball mill in absolute ethanol for 2 h, collect the ball-milled slurry and manually grind it in a mortar to obtain a dry powder, which is the fuel electrode powder;

[0067] Step 3, preparation of half cell: Weigh 0.35 g of the fuel electrode powder, press it into a green body under a pressure of 60 Mpa to obtain a fuel electrode green body. Weigh 0.15 g of the ball-milled BZCYYb electrolyte powder and spread it evenly on the fuel electrode green body, and co-press it into a green body under a pressure of 150 Mpa. Calcinate the co-pressed green body at 1450 °C for 10 h to obtain a half cell;

[0068] Step 4, preparation of air electrode slurry: Weigh 1 g of the air electrode material PNC0.9 powder, add 2 ml of ethylene glycol, 10 ml of isopropanol, and 1 ml of glycerol to a ball mill jar and ball mill for 1 h to obtain an air electrode slurry;

[0069] Step 5: Preparation of the full cell: The air electrode slurry is sprayed on the surface of the electrolyte of the half cell, and then the cell is transferred to a muffle furnace and calcined at 950 °C for 4 h to obtain a solid oxide single cell.

[0070] Comparative Example 3

[0071] This comparative example provides a method for preparing a fuel cell. The method for preparing the fuel cell in this comparative example is the same as that in Example 1 except for the different dosages of praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate. In this comparative example, 0.5 mol of praseodymium nitrate, 0.5 mol of potassium nitrate, 0.5 mol of cobalt nitrate and 0.5 mol of nickel nitrate are used.

[0072] Comparative Example 4

[0073] This comparative example provides a method for preparing a fuel cell. The difference between the method for preparing the fuel cell in this comparative example and that in Example 1 is that: in Step 1, after adding ethylenediaminetetraacetic acid and citric acid to the nitrate solution, ammonia water is not added to the nitrate solution to adjust the pH to 8, and the solution is directly stirred, and the remaining steps are the same.

[0074] Comparative Example 5

[0075] This comparative example provides a method for preparing a fuel cell. The difference between the method for preparing the fuel cell in this comparative example and that in Example 1 is that: the dosages of ethylenediaminetetraacetic acid and citric acid are different. In this comparative example, according to the molar ratio, ethylenediaminetetraacetic acid:citric acid:metal ions is 0.5:0.5:2.

[0076] 1. XRD Characterization

[0077] Figure 3 and Figure 4 The XRD patterns of... show that the prepared PNC and PNC0.9 are pure perovskite phases, while according to... it can be seen that the phase structure of NiO can be detected in the prepared KPNC. This is mainly because after introducing potassium element with a low valence state at the A site in the PrNi Figure 2 Co0 0.5 Co0 .5 O3 perovskite structure, through the defect regulation of the A site, the in-situ precipitation of nickel element at the B site is induced. Therefore, nickel element combines with oxygen element to obtain nickel oxide. The in-situ precipitation of nickel element improves the oxygen surface exchange and bulk diffusion rates of the electrode material, and promotes the catalytic activity of the oxygen reduction reaction. On the other hand, the in-situ dissolved nickel oxide nanoparticles have a strong interaction with the matrix and are closely chemically bonded. While improving the catalytic activity, the stability of the system is improved. Even at a relatively low working temperature of 500 °C to 700 °C, the electrode has a low polarization impedance and excellent catalytic activity.

[0078] 2. Impedance Characterization

[0079] Figure 6 and Figure 8 The EIS impedance diagrams in are tested under open-circuit voltage. Dry hydrogen is introduced on the fuel electrode side, and dry oxygen is on the air electrode side. The test temperature range is 450°C - 600°C, a bias voltage of 10 mV is applied, and the frequency range is 10 5 Hz - 0.1 Hz. According to Figure 8 , the polarization impedances of the PNC electrode at 600°C, 550°C, 500°C, and 450°C are 0.18 Ω / cm 2 , 0.26 Ω / cm 2 , 0.5 Ω / cm 2 , and 1.17 Ω / cm 2 , respectively. And according to Figure 6 , the polarization impedances of the KPNC electrode at 600°C, 550°C, 500°C, and 450°C are 0.04 Ω / cm 2 , 0.07 Ω / cm 2 , 0.13 Ω / cm 2 , and 0.22 Ω / cm 2 , respectively. The EIS test results show that even at a low temperature of 450°C, the KPNC electrode can exhibit a small polarization impedance, indicating that the PNC electrode doped with potassium elements has excellent oxygen catalytic activity and will not cause the impedance to increase due to the decrease in temperature. Combining with XRD, it can be known that the PNC material doped with potassium elements at the 7A site in-situ precipitates the NiO phase, improving the ORR catalytic activity.

[0080] 3. Power density characterization of single cells

[0081] Figure 7 and Figure 9 The I-V-P curve diagrams of the single cells in are tested under the conditions that dry hydrogen is introduced into the fuel electrode and dry oxygen is introduced into the air electrode. The test temperature range is 450°C - 600°C. It can be seen from Figure 9 that the maximum power densities of the PNC cell at test temperatures of 450°C - 600°C are 584 mW / cm 2 , 456 mW / cm 2 , 351 mW / cm 2 , and 272 mW / cm 2 , respectively; it can be seen from Figure 7 that the maximum power densities of the KPNC cell at test temperatures of 450°C - 600°C are 1097 mW / cm 2 , 902 mW / cm 2 , 707 mW / cm 2 , and 530 mW / cm 2It shows that the air electrode material of PNC doped with potassium element at the A site has excellent catalytic activity in the medium and low temperature ranges, which is of great significance for promoting the low-temperature development of high-performance proton ceramic fuel cells.

[0082] In Comparative Example 3, the stoichiometry of K was increased to 0.5, that is, the molecular formula was Pr 0.5 K 0.5 Ni 0.5 Co 0.5 O 3-δ (KPNC55), and its XRD pattern is as Figure 5 shown. It can be seen from the Figure 5 XRD pattern that when the stoichiometry of K was increased to 0.5, the air electrode powder sintered under the same conditions did not form a single perovskite phase. The reason is that the doping of low-valence K + led to an imbalance in valence states in the structure, forming respective oxide phases.

[0083] In Comparative Example 4, the solutions of praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate were not cross-linked under weakly alkaline conditions, and it was difficult for them to form a viscous gel, indicating that the solutions of praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate can only have a better cross-linking effect in a weakly alkaline environment.

[0084] In Comparative Example 5, less viscous gel was produced, indicating that too little amount of dispersant and complexing agent would cause the solutions of praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate to not cross-link completely, thereby affecting the comprehensive performance of the final battery.

[0085] See Figure 1 , an embodiment of the present invention provides a preparation method of a three-phase conducting air electrode material, including the following steps:

[0086] S102: Prepare a three-phase conducting air electrode material from praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate.

[0087] The preparation method of the three-phase conducting air electrode material provided by the present invention uses praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate as raw materials, so that the PrNi in the air electrode material can be 0.5 Co 0.5Introducing potassium element with a low valence state at the A-site in the O3 perovskite structure can increase the oxygen vacancy concentration in the system and improve the catalytic activity of the oxygen reduction reaction in proton ceramic fuel cells. On the other hand, through defect regulation at the A-site, in-situ precipitation of the B-site element nickel is induced, which can increase the oxygen surface exchange and bulk diffusion rates of the electrode material and promote the catalytic activity of the oxygen reduction reaction. Furthermore, the in-situ dissolved nickel can combine with oxygen elements to form nickel oxide nanoparticles. There is a strong interaction between the nickel oxide nanoparticles and the matrix, and the chemical bonding is tight. While improving the catalytic activity, the stability of the system is also enhanced, enabling the electrode to have a low polarization resistance and excellent catalytic activity even at a relatively low operating temperature of 500 °C to 700 °C.

[0088] In some embodiments, optionally, the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is (0.5 - 1.5):(0.2 - 0.8):(0.2 - 0.8):(0.05 - 0.25). For example, the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is (0.8 - 1.2):(0.3 - 0.7):(0.3 - 0.7):(0.1 - 0.2).

[0089] In this embodiment, controlling the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate to be (0.8 - 1.2):(0.3 - 0.7):(0.3 - 0.7):(0.1 - 0.2) can improve the preparation efficiency of the three-phase conducting air electrode material and also avoid waste of materials. For example, the molar ratio of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is 1:0.5:0.5:0.1 or 0.8:0.3:0.3:0.1 or 1.2:0.7:0.7:0.2.

[0090] In some embodiments, optionally, the steps of preparing the three-phase conducting air electrode material from praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate specifically include: dissolving praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate in a solvent, adding a dispersant and a complexing agent to obtain a mixed solution; adding an alkaline solution to the mixed solution to adjust the pH value of the mixed solution to a first preset value and heating the mixed solution to a first preset temperature to make the mixed solution into a viscous gel; drying the viscous gel to obtain a precursor powder of the three-phase conducting air electrode material; sintering the precursor powder at a second preset temperature to obtain the three-phase conducting air electrode material. Optionally, the dispersant includes ethylenediaminetetraacetic acid, the complexing agent includes citric acid, and the solvent includes deionized water.

[0091] In this embodiment, praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate are first dissolved in deionized water, and ethylenediaminetetraacetic acid and citric acid are added to obtain a mixed solution. Among them, ethylenediaminetetraacetic acid, as a dispersant, can prevent particles from aggregating, enabling raw materials such as praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate to be better dispersed in the solution, and thus making the components more uniform. Citric acid can cause raw materials such as praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate to form complexes. After forming the mixed solution, an alkaline solution is added to the mixed solution to adjust the pH value of the mixed solution to a first preset value, and the mixed solution is heated to a first preset temperature to make the mixed solution into a viscous gel. In this step, adding the alkaline solution is to adjust the system to be alkaline to ensure the normal progress of the reaction. After the mixed solution becomes a viscous gel, the viscous gel is dried to obtain a precursor powder of the three-phase conducting air electrode material. Finally, the precursor powder is sintered at a second preset temperature to obtain the three-phase conducting air electrode material. The preparation method of the three-phase conducting air electrode material provided by the present invention, by introducing potassium element with a low valence state at the A site in the PrNi 0.5 Co 0.5 O3 perovskite structure of the air electrode material, increases the oxygen vacancy concentration in the system and improves the catalytic activity of the oxygen reduction reaction of the proton ceramic fuel cell. On the other hand, through the defect regulation of the A site, the in-situ precipitation of element nickel at the B site is induced, improving the oxygen surface exchange and bulk diffusion rates of the electrode material and promoting the catalytic activity of the oxygen reduction reaction. On the other hand, the in-situ dissolved nickel can combine with oxygen element to form nickel oxide nanoparticles. There is a strong interaction between the nickel oxide nanoparticles and the matrix, and the chemical bonding is tight. While improving the catalytic activity, the stability of the system is improved, so that even at a relatively low working temperature of 500°C to 700°C, the electrode has a low polarization resistance and excellent catalytic activity.

[0092] In some embodiments, optionally, the alkaline solution includes ammonia water.

[0093] In this embodiment, the pH value of the solution can be adjusted to weakly alkaline by weakly alkaline ammonia water, which can ensure the gel formation efficiency, and thus ensure the production efficiency of the three-phase conducting air electrode material, and avoid reducing the catalytic effect of the three-phase conducting air electrode material due to too high acidity or alkalinity of the solution.

[0094] In some embodiments, optionally, the first preset value is greater than 7 and less than or equal to 9.

[0095] In this embodiment, the first preset value is greater than 7 and less than or equal to 9, that is, the gel environment of the raw materials of the three-phase conducting air electrode material is controlled to be a weakly alkaline environment, which can improve the production efficiency of the three-phase conducting air electrode material. For example, the first preset value is equal to 8.

[0096] In some embodiments, optionally, the first preset temperature is greater than or equal to 80°C and less than or equal to 90°C.

[0097] In this embodiment, the first preset temperature is greater than or equal to 80°C and less than or equal to 90°C, that is, the crosslinking temperature of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate is greater than or equal to 80°C and less than or equal to 90°C, which can ensure the formation of the air electrode material and improve the crosslinking rate. For example, the first preset temperature is equal to 80°C, 85°C, or 90°C.

[0098] In some embodiments, optionally, the second preset temperature is greater than or equal to 800°C and less than or equal to 1200°C.

[0099] In this embodiment, controlling the sintering temperature to be greater than or equal to 800°C and less than or equal to 1200°C can ensure the denseness of the structure of the three-phase conducting air electrode material and ensure the catalytic effect. For example, the second preset temperature is equal to 900°C, 1000°C, and 1100°C.

[0100] In some embodiments, optionally, the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions is (0.8 - 1.2):(0.8 - 1.2):(1.8 - 2.2), and the molar mass of the metal ions is equal to the sum of the molar masses of praseodymium nitrate, nickel nitrate, cobalt nitrate, and potassium nitrate.

[0101] In this embodiment, controlling the molar ratio of ethylenediaminetetraacetic acid, citric acid, and metal ions can maximize the dispersion effect and complexation effect of the raw materials of the three-phase conducting air electrode material. It can be understood that controlling the molar ratio of ethylenediaminetetraacetic acid to metal ions can make the raw materials of the three-phase conducting air electrode material disperse better in the solution, and then make the components more uniform. Controlling the molar ratio of citric acid to metal ions can make the raw materials of the three-phase conducting air electrode material form a complex, and the quality of citric acid determines the quality of the complexation effect and the quality of the sol. By controlling the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions in the present invention, the preparation rate and catalytic efficiency of the prepared electrode material can be improved. For example, the molar ratio of ethylenediaminetetraacetic acid:citric acid:metal ions is 1:1:2 or 1.1:1.1:2.1 or 0.8:0.8:1.8 or 1.2:1.2:2.2.

[0102] The second aspect of the present invention provides a three-phase conducting air electrode material, which is prepared according to the preparation method of the three-phase conducting air electrode material in any one of the embodiments of the first aspect of the present invention.

[0103] The third aspect of the present invention provides a fuel cell electrode, which is prepared from the three-phase conducting air electrode material of the embodiment of the second aspect of the present invention.

[0104] As Figure 10 shown, the fourth aspect of the present invention provides a fuel cell 1, which includes the fuel cell electrode 12 of the embodiment of the third aspect of the present invention.

[0105] In some embodiments, optionally, the fuel cell 1 is prepared by the following method: grinding nickel nitrate, BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ and starch in absolute ethanol to obtain a slurry, grinding the slurry in a mortar to obtain a dry fuel electrode powder, pressing the fuel electrode powder under a first preset pressure to form a fuel electrode green body; laying the BZCYYb electrolyte powder flat on the fuel electrode green body and co-pressing it under a second preset pressure to obtain a half-cell green body, calcining the half-cell green body at a third preset temperature to obtain a half-cell; adding the three-phase conducting air electrode material into an alcohol solution and grinding to obtain an air electrode slurry; spraying the air electrode slurry on one side surface of the BZCYYb electrolyte powder of the half-cell, and then calcining the half-cell after spraying the air electrode slurry at a fourth preset temperature to obtain the fuel cell 1.

[0106] In this embodiment, in the process of preparing the fuel electrode, nickel nitrate, BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ and starch are used as the fuel electrode, and BZCYYb is used as the electrolyte. BZCYYb is also BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ , where δ is the oxygen vacancy concentration. The generation of oxygen vacancies is mainly due to the doping of low-valence metal (Y / Yb) at the B site, which leads to the generation of oxygen vacancies in the system. Using the three-phase conducting air electrode material of the above embodiment as the air electrode, the fuel cell 1 is prepared by the co-pressing method. In this way, the fuel cell 1 of the present invention has a high oxygen reduction reaction catalytic activity. Even at a relatively low working temperature of 500 °C to 700 °C, the electrode has a low polarization impedance and excellent catalytic activity.

[0107] In some embodiments, optionally, the first preset pressure is greater than or equal to 50 Mpa and less than or equal to 70 Mpa; for example, 50 Mpa, 60 Mpa, 70 Mpa, the second preset pressure is greater than or equal to 140 Mpa and less than or equal to 160 Mpa; for example, 140 Mpa, 150 Mpa, 160 Mpa, the third preset temperature is greater than or equal to 1400 °C and less than or equal to 1500 °C; for example, 1400 °C, 1450 °C, 1500 °C, and the fourth preset temperature is greater than or equal to 900 °C and less than or equal to 1000 °C; for example, 900 °C, 950 °C, 1000 °C.

[0108] In this embodiment, by controlling the pressing pressure and calcination temperature of each step, the structural stability of the fuel cell 1 can be improved, and the catalytic activity of the oxygen reduction reaction can be enhanced.

[0109] In some embodiments, optionally, the alcohol solution includes ethylene glycol, isopropyl alcohol, and glycerol.

[0110] In this embodiment, a mixed alcohol of ethylene glycol, isopropyl alcohol, and glycerol is selected to dissolve the three-phase conducting air electrode material. In this way, ethylene glycol serves as a solvent, isopropyl alcohol serves as a dispersant, and glycerol serves as a binder. The mixture of the three combines with the air electrode powder to obtain a uniformly mixed electrode paste after ball milling, which is used for electrode spraying on the surface of the electrolyte of the half-cell, while a single alcohol cannot achieve the effect of uniform mixing.

[0111] In some embodiments, optionally, the volume ratio of ethylene glycol, isopropyl alcohol, and glycerol is (1 - 3):(8 - 12):(0.5 - 1.5), such as 2:10:1 or 3:10:1.

[0112] Although this specification contains many specific implementation details, these should not be construed as limiting the scope of any invention or the scope of what is claimed, but are mainly used to describe the features of specific embodiments of a particular invention. Certain features described in multiple embodiments in this specification can also be combined and implemented in a single embodiment. On the other hand, various features described in a single embodiment can also be separately implemented in multiple embodiments or implemented in any suitable sub-combination. Additionally, although features may function in certain combinations as described above and were even initially claimed as such, one or more features from the claimed combination can in some cases be removed from the combination, and the claimed combination can be directed to a sub-combination or a variant of the sub-combination.

[0113] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring that these operations be performed in the particular order shown or performed sequentially, or requiring that all illustrated operations be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system modules and components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product, or packaged into multiple software products.

[0114] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous.

[0115] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0116] The above is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A preparation method of a three-phase conductive air electrode material, characterized in that, Including: The three-phase conductive air electrode material is prepared from praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate.

2. The method for preparing the three-phase conductive air electrode material according to claim 1, wherein The molar ratio of the praseodymium nitrate, the nickel nitrate, the cobalt nitrate and the potassium nitrate is (0.5 - 1.5):(0.2 - 0.8):(0.2 - 0.8):(0.05 - 0.25).

3. The method for preparing the three-phase conductive air electrode material according to claim 2, wherein The molar ratio of the praseodymium nitrate, the nickel nitrate, the cobalt nitrate and the potassium nitrate is (0.8 - 1.2):(0.3 - 0.7):(0.3 - 0.7):(0.1 - 0.2).

4. The preparation method of the three-phase conductive air electrode material according to claim 1, characterized in that, The step of preparing the three-phase conductive air electrode material from praseodymium nitrate, nickel nitrate, cobalt nitrate and potassium nitrate specifically includes: Dissolve the praseodymium nitrate, the nickel nitrate, the cobalt nitrate and the potassium nitrate in a solvent, and add a dispersant and a complexing agent to obtain a mixed solution; Add an alkaline solution to the mixed solution to adjust the pH value of the mixed solution to a first preset value, and heat the mixed solution to a first preset temperature to make the mixed solution into a viscous gel; Dry the viscous gel to obtain a precursor powder of the three-phase conductive air electrode material; Sinter the precursor powder at a second preset temperature to obtain the three-phase conductive air electrode material.

5. The preparation method of the three-phase conductive air electrode material according to claim 4, characterized in that, The alkaline solution includes ammonia water.

6. The preparation method of the three-phase conductive air electrode material according to claim 4, wherein The first preset value is greater than 7 and less than or equal to 9.

7. The preparation method of the three-phase conductive air electrode material according to claim 4, characterized in that, The first preset temperature is greater than or equal to 80°C and less than or equal to 90°C.

8. The preparation method of the three-phase conductive air electrode material according to claim 4, characterized in that, The second preset temperature is greater than or equal to 800°C and less than or equal to 1200°C.

9. The method for preparing the three-phase conductive air electrode material according to claim 4, wherein The dispersant includes ethylenediaminetetraacetic acid, and the complexing agent includes citric acid.

10. The method for preparing the three-phase conductive air electrode material according to claim 9, wherein The molar ratio of the ethylenediaminetetraacetic acid: the citric acid: the metal ions is (0.8 - 1.2):(0.8 - 1.2):(1.8 - 2.2), and the molar mass of the metal ions is equal to the sum of the molar masses of the praseodymium nitrate, the nickel nitrate, the cobalt nitrate and the potassium nitrate.

11. The method for preparing the three-phase conductive air electrode material according to claim 10, wherein The molar ratio of the ethylenediaminetetraacetic acid: the citric acid: the metal ions is 1:1:

2.

12. The preparation method of the three-phase conductive air electrode material according to claim 4, wherein, The solvent includes deionized water.

13. A three-phase conductive air electrode material, wherein The three-phase conductive air electrode material is prepared by the method for preparing the three-phase conductive air electrode material according to any one of claims 1 to 12.

14. A fuel cell electrode, characterized in that, The fuel cell electrode is prepared from the three-phase conductive air electrode material according to claim 13.

15. A fuel cell, characterized in that, Including: The fuel cell electrode according to claim 14.

16. The fuel cell according to claim 15, wherein The fuel cell is prepared by the following method: Nickel nitrate, BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ and starch are ground in ethanol to obtain a slurry. The slurry is placed in a mortar and ground to obtain a dry fuel electrode powder. The fuel electrode powder is pressed into a shape under a first preset pressure to obtain a green fuel electrode body; The BZCYYb electrolyte powder is laid flat on the green body of the fuel electrode and co-pressed into a green body of a half-cell under a second preset pressure. The green body of the half-cell is calcined at a third preset temperature to obtain a half-cell; The three-phase conducting air electrode material is added to an alcohol solution and ground to obtain an air electrode slurry; The air electrode slurry is sprayed on one side surface of the BZCYYb electrolyte powder of the half-cell, and then the half-cell sprayed with the air electrode slurry is calcined at a fourth preset temperature to obtain the fuel cell.

17. The fuel cell according to claim 16, wherein The ethanol is anhydrous ethanol.

18. The fuel cell according to claim 16, wherein The first preset pressure is greater than or equal to 50 Mpa and less than or equal to 70 Mpa; The second preset pressure is greater than or equal to 140 Mpa and less than or equal to 160 Mpa; The third preset temperature is greater than or equal to 1400 °C and less than or equal to 1500 °C; The fourth preset temperature is greater than or equal to 900 °C and less than or equal to 1000 °C.

19. The fuel cell according to claim 16, characterized in that, The alcohol solution includes ethylene glycol, isopropanol, and glycerol.

20. The fuel cell according to claim 19, wherein, The volume ratio of the ethylene glycol, the isopropanol, and the glycerol is (1 - 3):(8 - 12):(0.5 - 1.5).

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