Reversible proton ceramic battery composite air electrode material and preparation method thereof

Abstract

The invention relates to a reversible proton ceramic battery composite air electrode material, the composite air electrode material comprises an air electrode base material and a coating layer coating the air electrode base material, the air electrode base material is a Co-based A-site layered perovskite oxide, the chemical formula is LnBaCo2O5 + delta, Ln is equal to La, Pr, Sm and Gd, the coating layer material is a Fe-based single perovskite oxide, and the thickness of the coating layer is smaller than that of the Co-based A-site layered perovskite oxide. The chemical formula of the material is BaFe < 1-y > PryO < 3-delta >. The LnBaCo2O5 + delta air electrode base material is coated with BaFe < 1-y > PryO < 3-delta >, so that the protonation capability of the air electrode material is improved, the catalytic activity is improved, and a three-phase interface of a redox reaction is expanded, and the electrochemical performance of the air electrode material is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide reversible batteries, and in particular to a reversible proton ceramic battery composite air electrode material and a preparation method thereof. Background Art

[0002] Solid oxide cells (SOCs) are highly efficient, reversible energy conversion devices that combine energy conversion and storage. Their forward and reverse operating characteristics (forward power generation, reverse water electrolysis) make them a key technology for the efficient storage and utilization of renewable energy. Their development aligns with the core needs of the global energy system's transition to an efficient, clean, and flexible one. Electrolytes are a key component of SOCs. Compared to traditional oxygen ion-conducting electrolytes, proton-conducting solid electrolytes have low proton migration activation energies (0.4–0.6 eV). This allows proton ceramic electrochemical cells (PCECs) to operate at low to medium temperatures (400–700°C), reducing sealing pressure and providing more options for key materials. However, the extremely slow oxygen reduction (ORR) and oxygen evolution (OER) kinetics of air at low to medium temperatures significantly reduce the electrochemical performance of PCECs. Therefore, developing high-performance air cathode materials is crucial for the development of PCECs.

[0003] Co-based A-site layered perovskite oxide LnBaCo2O 5+δ It is usually used as the air electrode material of PCEC due to its high electrical conductivity and good catalytic activity. 5+δ As a traditional mixed oxygen ion-electron conductor, the material has weak proton conductivity, which limits the electrode reaction to the three-phase interface, causing excessive local current density, stress concentration, and thus electrode peeling. In order to improve the proton conductivity, fixed-valence elements such as Zr and Ce with strong alkalinity are usually doped at the B position. Low doping concentration has limited effect on the improvement of proton conductivity, while high doping amount will significantly reduce its electronic conductivity and affect its electrochemical activity. There is an inherent contradiction between the two that is difficult to optimize synergistically. Secondly, element doping may affect its solid solubility due to different preparation methods, thereby affecting phase purity. In addition, due to the LnBaCo2O 5+δ The material has a layered structure with alternating Ln and Ba at the A-site. The difference in ionic radius between the Ln and Ba layers leads to stress within the lattice. This can easily cause Ba segregation under long-term high-temperature operation, leading to degradation of the air cathode material and performance degradation. Currently, Ba segregation is mainly alleviated by doping the A-site with elements such as Sr and Ca, which have smaller ionic radii. However, this measure reduces the basicity of the material and is not conducive to increasing the proton concentration.

[0004] Therefore, developing air electrode materials with high proton conductivity, high electrochemical activity and excellent stability is the core challenge in promoting the development of reversible proton ceramic battery technology. The performance optimization directly determines the power density and long-term service life of the battery system. Summary of the Invention

[0005] The present invention provides a reversible proton ceramic battery composite air electrode material, the composite air electrode material comprising an air electrode matrix material and a coating layer coated on the air electrode matrix material, the air electrode matrix material is a Co-based A-site layered perovskite oxide, and the coating layer material is an Fe-based single perovskite oxide.

[0006] Furthermore, the molecular formula of the air electrode matrix material is LnBaCo2O 5+δ , where Ln = La, Pr, Sm, Gd, and δ is the non-stoichiometric amount of oxygen.

[0007] Furthermore, the molecular formula of the coating material is BaFe 1-y Pr y O 3-δ , the coating layer has a cubic structure, wherein y=0.05~0.2, preferably, y=0.1.

[0008] Furthermore, the mass percentage of the coating layer material is 5-20%, and preferably, the mass percentage of the coating layer material is 10%.

[0009] The present invention also provides a method for preparing a composite air electrode material for a reversible proton ceramic battery. The composite air electrode material has the chemical formula: (1-x)LnBaCo2O 5+δ +xBaFe 1-y Pr y O 3-δ , where Ln = La, Pr, Sm, Gd, δ is the non-stoichiometric amount of oxygen, x = 5 to 20 wt%, y = 0.05 to 0.2, where LnBaCo2O 5+δ As the matrix material, BaFe 1-y Pr y O 3-δ The coating layer is compounded on the base material by at least one of physical vapor deposition method, impregnation method, sol-gel method and mechanical mixing method.

[0010] Furthermore, the LnBaCo2O 5+δ Prepared by the following method:

[0011] S1: dissolving Ln salt or Ln oxide, Ba salt, and Co salt in dilute nitric acid in a stoichiometric ratio, adding citric acid and ethylenediaminetetraacetic acid as chelating agents, and adjusting the pH to 5-9 by adding ammonia water to obtain a clear solution, placing the obtained clear solution in a water bath at 50-120°C and evaporating it to a gel state;

[0012] S2: The gel obtained in step S1 is placed in an oven at 50-120°C for 8-12 hours to obtain a dry gel, and the obtained dry gel is heated at 150-300°C until self-propagating combustion is carried out to form fluffy and porous LnBaCo2O 5+δ Precursor powder;

[0013] S3: Grind the precursor powder obtained in step S2 and remove carbon at 350-600°C for 3-6 hours, then calcine at 900-1150°C for 2-6 hours to obtain LnBaCo2O 5+δ Air electrode matrix material powder.

[0014] Furthermore, the Ln salt is Ln(NO3)3·6H2O, the Ln oxide is Ln2O3, the Ba salt is Ba(NO3)2, and the Co salt is Co(NO3)2·6H2O. The dilute nitric acid is 5-25wt% nitric acid. The molar ratio of the total metal ions in the Ln salt or Ln oxide, Co salt to citric acid is 1:1-2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in the Ba salt is 1:1-1.5.

[0015] Furthermore, the LnBaCo2O 5+δ Prepared by the following method:

[0016] Ln2O3, BaCO3, and Co3O4 are added to a ball mill according to a stoichiometric ratio, alcohol is added as a solvent, the mass ratio of powder to alcohol is 1:1-2, zirconia balls are used as ball milling media, the mass ratio of powder to zirconia balls is 1:3-5, and the precursor powder is obtained after uniform mixing at a speed of 300-400 rpm in a ball mill for 10-24 hours. The obtained precursor powder is ground and calcined at 1100-1200°C for 2-10 hours to obtain the air electrode matrix material LnBaCo2O 5+δ .

[0017] Furthermore, the LnBaCo2O 5+δ Prepared by the following method:

[0018] Ln(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were added to deionized water in a stoichiometric ratio, heated and stirred to dissolve, and three clear nitrate solutions were prepared, each with a concentration of 0.5-1 mol / L. C6H5COONH4 was used as a precipitant raw material, and the molar ratio of the precipitant to the metal ion was 5:1. A peristaltic pump was used to titrate to form a precipitate, and an electric stirrer was used to stir the precipitate at a speed of 100-600 rpm to ensure a uniform reaction. The precipitate was then washed and filtered repeatedly with deionized water in an ultrasonic machine to obtain LnBaCo2O. 5+δ The precursor powder is ground and calcined at 1050-1200°C for 2-10 hours to obtain the air electrode matrix material LnBaCo2O 5+δ .

[0019] Furthermore, BaFe 1-y Pr y O 3-δ The method of coating on the base material is:

[0020] Pr salt, Ba salt, and Co salt were dissolved in deionized water according to the stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid were added as chelating agents, and ammonia was added to adjust the pH value to 5-9 to obtain a clear solution. A certain mass fraction of LnBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 150 to 300° C. until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder. The obtained precursor powder is ground and then carbonized at 350 to 600° C. for 3 to 6 hours, and then calcined at 900 to 1150° C. for 2 to 6 hours to obtain a reversible proton ceramic battery composite air electrode material (1-x)LnBaCo2O 5+δ +x BaFe 1-y Pr y O 3-δ Pure phase powder.

[0021] Furthermore, the molar ratio of the total metal ions in the Pr salt and the Co salt to citric acid is 1:1-2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in the Ba salt is 1:1-1.5.

[0022] The present invention also provides a reversible proton ceramic battery, wherein the air electrode material of the reversible proton ceramic battery includes the above-mentioned air electrode material.

[0023] The present invention adopts LnBaCo2O 5+δ BaFe coated on the air electrode substrate1-y Pr y O 3-δ , which is beneficial to improve the protonation ability of the air electrode material, enhance the catalytic activity, and expand the three-phase interface of the redox reaction, thereby significantly improving the electrochemical performance of the air electrode material. 1-y Pr y O 3-δ There are a lot of oxygen vacancies, which are conducive to the adsorption and dissociation of H2O, forming sufficient proton defects; secondly, the cubic phase of BaFe 1-y Pr y O 3-δ It provides a continuous three-dimensional transmission channel for proton migration and coordinates the proton transmission path between the bulk and the interface. Finally, the coating layer BaFe 1-y Pr y O 3-δ Ba has a high chemical potential, which inhibits the 5+δ The Ba element in the matrix material segregates toward the surface, which helps maintain the structural stability of the air electrode material and prolongs its service life. As a result, the proton ceramic battery composite air electrode material exhibits excellent electrochemical performance in both fuel cell mode and electrolytic cell mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is the XRD pattern of the composite air cathode material powder and SBC prepared in Examples 1-3 of the present invention;

[0025] Figure 2 This is the polarization impedance curve of a symmetrical battery with the SBC+5BFP10 composite air electrode prepared in Example 1 of the present invention and BZCYY as the electrolyte;

[0026] Figure 3 This is the polarization impedance curve of a symmetrical battery with the SBC+10BFP10 composite air electrode prepared in Example 2 of the present invention and BZCYY as the electrolyte;

[0027] Figure 4 This is the polarization impedance curve of a symmetrical battery with the SBC+20BFP10 composite air electrode prepared in Example 3 of the present invention and BZCYY as the electrolyte;

[0028] Figure 5 This is the polarization impedance curve of the symmetrical battery with SBC air electrode and BZCYY as electrolyte;

[0029] Figure 6 The curves of the polarization impedance of the composite air electrodes and SBCs prepared in Examples 1-3 of the present invention as a function of temperature are shown;

[0030] Figure 7This is the IVP curve of a single cell with SBC+10BFP10 as the air electrode in fuel cell mode;

[0031] Figure 8 is the IVP curve of a single cell with SBC as the air electrode in fuel cell mode;

[0032] Figure 9 This is the IV curve of a single cell with SBC+10BFP10 as the air electrode in electrolytic cell mode;

[0033] Figure 10 This is the IV curve of a single cell with SBC as the air electrode in fuel cell mode. DETAILED DESCRIPTION

[0034] The reversible proton ceramic battery composite air electrode material of the present invention is based on the existing Co-based A-site layered perovskite oxide LnBaCo2O 5+δ On the basis of a layer of BaFe 1-y Pr y O 3-δ The invention comprises an air electrode base material and a coating layer coated on the air electrode base material, wherein the air electrode base material is a Co-based A-site layered perovskite oxide, and the coating layer material is an Fe-based single perovskite oxide. Specifically, the molecular formula of the air electrode base material is LnBaCo2O 5+δ , where Ln = La, Pr, Sm, Gd, and the molecular formula of the coating layer is BaFe 1-y Pr y O 3-δ , the coating layer has a cubic structure.

[0035] The main principle is that the coating layer BaFe 1-y Pr y O 3-δ It is a triple conductor with the ability to conduct oxygen ions, protons, and electrons. It has a large number of oxygen vacancies, which is conducive to the adsorption and dissociation of H2O and the formation of sufficient proton defects. Secondly, the cubic phase of BaFe 1-y Pr y O 3-δ It provides a continuous three-dimensional transmission channel for proton migration and coordinates the proton transmission path between the bulk and the interface. Finally, the coating layer BaFe 1-y Pr y O 3-δ The high chemical potential of Ba inhibits the 5+δ The Ba element in the matrix material segregates toward the surface, which helps maintain the structural stability of the air electrode material and prolongs its service life. As a result, the proton ceramic battery composite air electrode material exhibits excellent electrochemical performance in both fuel cell mode and electrolytic cell mode.

[0036] Therefore, by LnBaCo2O 5+δ BaFe coated on the base material 1-y Pr y O 3-δ , which is beneficial to improving the protonation ability of air electrode materials, enhancing catalytic activity, and expanding the three-phase interface of redox reactions, thereby significantly improving the electrochemical performance of air electrode materials.

[0037] The chemical formula of this composite air cathode material can be expressed as: (1-x)LnBaCo2O 5+δ +xBaFe 1-y Pr y O 3-δ , where x = 5-20 wt%, y = 0.05-0.2, Ln = La, Pr, Sm, Gd, and δ is the non-stoichiometric amount of oxygen. In some embodiments of the present invention, x = 5-20 wt%, preferably, specifically 10 wt%. A too low content of x will affect the protonation ability of the composite air electrode material, while a too high content of x will affect the interfacial bonding with the electrolyte. y = 0.05-0.2, preferably, specifically 0.1. Both too low and too high a content of y will destroy the cubic phase.

[0038] The matrix material of the composite air electrode material of the present invention is LnBaCo2O 5+δ The substrate material can be prepared by at least one of a sol-gel method, a coprecipitation method, or a solid-phase reaction method. The substrate material can be coated by at least one of a mechanical mixing method, a physical vapor deposition method, an impregnation method, and a sol-gel method. Preferably, the coating method is the sol-gel method.

[0039] Specifically, the preparation method of the reversible proton ceramic battery composite air electrode material of the present invention comprises the following steps:

[0040] S1: dissolving Ln salt or Ln oxide, Ba salt, and Co salt in dilute nitric acid in a stoichiometric ratio, adding citric acid and ethylenediaminetetraacetic acid as chelating agents, and adjusting the pH to 5-9 by adding ammonia water to obtain a clear solution, placing the obtained clear solution in a water bath at 50-120°C and evaporating it to a gel state;

[0041] S2: The gel obtained in step S1 is placed in an oven at 50-120°C for 8-12 hours to obtain a dry gel, and the obtained dry gel is heated at 150-300°C until self-propagating combustion is carried out to form fluffy and porous LnBaCo2O 5+δ Precursor powder;

[0042] S3: Grind the precursor powder obtained in step S2 and remove carbon at 350-600°C for 3-6 hours, then calcine at 900-1150°C for 2-6 hours to obtain LnBaCo2O 5+δ Air electrode matrix material powder;

[0043] The above steps S1-S3 obtain the matrix material LnBaCo2O 5+δ The above-mentioned base material will be coated below.

[0044] S4: Pr salt, Ba salt, and Co salt were dissolved in deionized water according to the stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid were added as chelating agents, and ammonia was added to adjust the pH value to 5-9 to obtain a clear solution. A certain mass fraction of LnBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 150 to 300° C. until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder. The obtained precursor powder is ground and then carbonized at 350 to 600° C. for 3 to 6 hours, and then calcined at 900 to 1150° C. for 2 to 6 hours to obtain a reversible proton ceramic battery composite air electrode material (1-x)LnBaCo2O 5+δ +x BaFe 1-y Pr y O 3-δ Pure phase powder.

[0045] Specifically, the molar ratio of the total metal ions in the Pr salt and the Co salt to citric acid is 1:1-2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in the Ba salt is 1:1-1.5.

[0046] Several embodiments are given below to describe the preparation method in detail:

[0047] Example 1:

[0048] 95wt% SmBaCo2O 5+δ +5wt%BaFe 0.9 Pr 0.1 O 3-δ (Abbreviated as SBC+5BFP10) Composite air cathode material powder preparation

[0049] Sm2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Sm and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous SmBaCo2O 5+δ Precursor powder, SmBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain SmBaCo2O 5+δ Air electrode matrix material powder;

[0050] Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water in a stoichiometric ratio. Citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions in Ba(NO3)2 to ethylenediaminetetraacetic acid was 1:1. Ammonia water was added to adjust the pH to 7. The solution was stirred continuously to obtain a clear solution. 95 wt% of SmBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material SBC+5BFP10.

[0051] Example 2

[0052] 90wt% SmBaCo2O 5+δ +10wt%BaFe 0.9 Pr 0.1 O 3-δ , (abbreviated as SBC+10BFP10) composite air cathode material powder preparation

[0053] Sm2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Sm and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous SmBaCo2O 5+δ Precursor powder, SmBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain SmBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 90wt% of SmBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material SBC+10BFP10.

[0054] Example 3

[0055] 80wt% SmBaCo2O 5+δ +20wt%BaFe 0.9 Pr 0.1 O 3-δ , (abbreviated as SBC+20BFP10) composite air cathode material powder preparation

[0056] Sm2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Sm and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous SmBaCo2O 5+δ Precursor powder, SmBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain SmBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 80wt% of SmBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material SBC+20BFP10.

[0057] Example 4

[0058] 90wt% SmBaCo2O 5+δ +10wt%BaFe 0.95 Pr 0.05 O 3-δ , (abbreviated as SBC+10BFP5) composite air cathode material powder preparation

[0059] Sm2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Sm and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous SmBaCo2O 5+δ Precursor powder, SmBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain SmBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 90wt% of SmBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material SBC+10BFP5.

[0060] Example 5

[0061] 90wt% SmBaCo2O 5+δ +10wt%BaFe 0.8 Pr 0.2 O 3-δ , (abbreviated as SBC+10BFP20) composite air cathode material powder preparation

[0062] Sm2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Sm and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous SmBaCo2O 5+δ Precursor powder, SmBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain SmBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 90wt% of SmBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material SBC+10BFP20.

[0063] Example 6

[0064] 90wt% LaBaCo2O 5+δ +10wt%BaPr 0.1 Fe 0.9 O 3-δ , (abbreviated as LBC+10BFP10) composite air cathode material powder preparation

[0065] La2O3, Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of La and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous LaBaCo2O 5+δ Precursor powder, LaBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain LaBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions in Ba(NO3)2 to ethylenediaminetetraacetic acid was 1:1. Ammonia water was added to adjust the pH to 7, and the solution was stirred continuously to obtain a clear solution. 90wt% of LaBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material LBC+10BFP10.

[0066] Example 7

[0067] 90wt%PrBaCo2O 5+δ +10wt%BaFe 0.9 Pr 0.1 O 3-δ , (abbreviated as PBC+10BFP10) composite air cathode material powder preparation

[0068] Pr6O 11Ba(NO3)2, and Co(NO3)2·6H2O are dissolved in 5-25wt% dilute nitric acid in a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid are added as chelating agents, the molar ratio of the sum of Pr and Co metal ions to citric acid is 1:2, and the molar ratio of Ba ions in Ba(NO3)2 to ethylenediaminetetraacetic acid is 1:1. Ammonia water is added to adjust the pH value to 7, and the solution is stirred continuously to obtain a clear solution. The obtained clear solution is placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel is placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form fluffy and porous PrBaCo2O 5+δ Precursor powder, PrBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain PrBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions in Ba(NO3)2 to ethylenediaminetetraacetic acid was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 90wt% of PrBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and then the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material PBC+10BFP10.

[0069] Example 8

[0070] 90wt%GdBaCo2O 5+δ +10wt%BaPr 0.1 Fe 0.9 O 3-δ Preparation of composite air cathode material powder (abbreviated as GBC+10BFP10)

[0071] Gd2O3, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in 5-25wt% dilute nitric acid according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the total Gd and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in Ba(NO3)2 was 1:1. Ammonia water was added to adjust the pH value to 7, and the solution was stirred continuously to obtain a clear solution. The obtained clear solution was placed in a water bath and evaporated in a water bath at 80°C to a gel state. The gel was placed in an oven at 85°C for 8-12 hours to obtain a dry gel. The obtained dry gel was heated at 250°C until self-propagating combustion occurred to form fluffy and porous GdBaCo2O 5+δ Precursor powder, GdBaCo2O 5+δ The precursor powder was ground and decarbonized at 400 °C for 4 hours, and then calcined at 1000 °C for 2 hours to obtain GdBaCo2O 5+δ Air cathode matrix material powder; Pr(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O were dissolved in deionized water according to a stoichiometric ratio, and citric acid and ethylenediaminetetraacetic acid were added as chelating agents. The molar ratio of the sum of Pr and Co metal ions to citric acid was 1:2, and the molar ratio of Ba ions in Ba(NO3)2 to ethylenediaminetetraacetic acid was 1:1. Ammonia water was added to adjust the pH to 7, and a clear solution was obtained by continuous stirring. 90wt% of PrBaCo2O was weighed. 5+δ The air electrode matrix material is added to a clarified solution, heated and stirred for 2 to 3 hours, and the solution is placed in an ultrasonic device for half an hour. The solution is then placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 250°C until self-propagating combustion occurs to form a fluffy and porous composite air electrode material precursor powder; the obtained precursor powder is ground and carbonized at 400°C for 4 hours, and then calcined at 900°C for 2 hours to obtain a pure phase powder of the reversible proton ceramic battery composite air electrode material GBC+10BFP10.

[0072] In the above embodiment, the sol-gel method was mainly used to prepare the matrix material LnBaCo2O 5+δ However, the above matrix material can also be prepared by solid phase reaction method or co-precipitation method. Specifically:

[0073] Solid phase reaction method: Ln2O3, BaCO3, and Co3O4 are added to a ball mill according to a stoichiometric ratio, alcohol is added as a solvent, the mass ratio of powder to alcohol is 1:1-2, zirconia balls are used as ball milling media, and the mass ratio of powder to zirconia balls is 1:3-5. After uniformly mixing at a speed of 300-400 rpm in a ball mill for 10-24 hours, a precursor powder is obtained. The obtained precursor powder is ground and calcined at 1100-1200°C for 10 hours to obtain the air electrode matrix material LnBaCo2O 5+δ .

[0074] Co-precipitation method: Ln(NO3)3·6H2O, Ba(NO3)2, and Co(NO3)2·6H2O are added to deionized water in a stoichiometric ratio, heated and stirred to dissolve, and three nitrate clear solutions are prepared respectively, with a concentration of 0.5-1 mol / L; C6H5COONH4 is used as the precipitant raw material, and the molar ratio of the precipitant to the metal ion is 5:1. A peristaltic pump is used to add the nitrate solution dropwise to the precipitant solution at a flow rate of 4.5-15 mL / min to form a precipitate. At the same time, an electric stirrer is used to stir the precipitate at a speed of 100-600 rpm to ensure uniform reaction. After continuous stirring for 12 hours, deionized water is used for shaking washing and filtration in an ultrasonic machine. After repeating three times, the precipitate obtained is LnBaCo2O 5+δ The precursor powder is ground and calcined at 1050-1200 ° C for 10 hours to obtain the air electrode matrix material LnBaCo2O 5+δ .

[0075] The air cathode material of the present invention coats the base material. For comparison, the present invention provides several uncoated air cathode materials: SmBaCo2O 5+δ (abbreviated as SBC), LaBaCo2O 5+δ (abbreviated as LBC), PrBaCo2O 5+δ (abbreviated as PBC), GdBaCo2O 5+δ (abbreviated as GBC) for comparison.

[0076] (1) X-ray diffraction (XRD) test analysis

[0077] The air cathode materials prepared in Examples 1-3 and Comparative Example 1 were characterized by XRD test. Figure 1, showing a comparison of the powder XRD patterns of SBC+5BFP10, SBC+10BFP10, SBC+20BFP10, and SBC, it can be seen that all characteristic peaks correspond to the SBC and BFP10 phases, with no characteristic peaks of other impurities. In particular, the characteristic peaks of BFP10 are highly consistent with its cubic phase structure (space group Pm-3m). As the mass percentage of the coating layer BFP10 increases, the characteristic peaks of BFP10 are significantly enhanced. This indicates that the preparation method provided by the present invention can synthesize pure phase powders of the composite air cathode material SBC+xBFP10 (x=5, 10, 20wt%).

[0078] (2) Electrochemical performance test

[0079] 0.2g of each of Examples 1-3 and 0.01g of each of PMMA and SBC air cathode material were weighed and mixed, 0.01g of ethyl cellulose and 0.15g of terpineol were added and ground into a uniform slurry. The mixed slurry was evenly coated on the dense BaZr by screen printing. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ The two sides of the (abbreviated as BZCYY) electrolyte sheet were calcined at 1150℃ for 2 hours to obtain a symmetrical battery with porous air electrodes on both sides. The symmetrical battery was placed in an atmosphere tube furnace and air containing 5vol% H2O was introduced to test the surface specific resistance (ASR) of the air electrode material at different temperatures. Similarly, the mixed air electrode slurry was evenly coated on the electrolyte sheet side of the NiO-BZCYY|BZCYY half-cell by screen printing and calcined at 1150℃ for 2 hours to obtain a single cell. The single cell was placed in an atmosphere tube furnace and air containing 5vol% H2O was introduced to the air electrode side and hydrogen containing 3vol% H2O was introduced to the fuel electrode side. The electrochemical performance of the single cell was tested at different temperatures in fuel cell mode and electrolytic cell mode.

[0080] like Figure 2 As shown, the surface resistivity of the symmetrical battery with SBC+5BFP10 as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.08, 0.17, 0.40, and 1.00Ωcm, respectively. 2 .

[0081] like Figure 3 As shown, the surface resistivity of the symmetrical battery with SBC+10BFP10 as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.06, 0.15, 0.33, and 0.89Ωcm, respectively. 2 .

[0082] like Figure 4As shown, the surface resistivity of the symmetrical battery with SBC+20BFP10 as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.11, 0.22, 0.46, and 1.02Ωcm, respectively. 2 .

[0083] like Figure 5 As shown, the surface resistivity of the symmetrical battery with SBC as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.13, 0.31, 0.74, and 2.09Ωcm, respectively. 2 .

[0084] It can be seen that the surface resistivity of the SBC+x BFP10 (x=5, 10, 20 wt%) composite air cathode material of the present invention is significantly improved compared with the air cathode matrix material SBC, and its corresponding activation energy is significantly reduced (see Figure 6 ), indicating that coating BP10F on the SBC surface improves the catalytic activity of the composite air electrode material, provides more options for the transmission path of proton migration, and reduces the activation energy of the redox reaction.

[0085] The ASR values of the symmetrical cells of Examples 1-8 and SBC, LBC, PBC, and GBC at 700°C are shown in Table 1. Composite air electrode material (1-x) LnBaCo2O 5+δ +xBaFe 1-y Pr y O 3-δ The surface resistivity is relative to that of the air electrode matrix material LnBaCo2O 5+δ All of them have decreased significantly, indicating that BaFe 1-y Pr y O 3-δ Coated with LnBaCo2O 5+δ All of them improve their electrochemical properties, and are universally applicable when Ln in the material is La, Pr, Sm, or Gd, meeting the requirements of air electrode materials for reversible proton ceramic batteries.

[0086] Table 1 Electrochemical performance test results

[0087] <![CDATA[Surface specific resistance (Ωcm 2 )]]> SBC+5BFP10 0.08 SBC+10BFP10 0.06 SBC+20BFP10 0.11 SBC+10BFP5 0.08 SBC+10BFP20 0.07 LBC+10BFP10 0.07 PBC+10BFP10 0.08 GBC+10BFP10 0.06 SBC 0.13 LBC 0.12 PBC 0.13 GBC 0.12

[0088] like Figure 7 As shown in Figure 2, the maximum power density of the single cell with SBC+10BFP10 as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.75, 0.5, 0.33, and 0.18 W cm, respectively. -2 .

[0089] like Figure 8As shown in Figure 2, the maximum power densities of the single cell with SBC as the air electrode at 700℃, 650℃, 600℃, and 550℃ are 0.62, 0.44, 0.26, and 0.14 W cm, respectively. -2 .

[0090] like Figure 9 As shown in the figure, the maximum current density of the single cell with SBC+10BFP10 as the air electrode at a voltage of 1.3 V is 1.54, 0.91, 0.53, and 0.25 A cm at 700 ° C, 650 ° C, 600 ° C, and 550 ° C, respectively. -2 .

[0091] like Figure 10 As shown in the figure, the maximum current density of the single cell with SBC as the air electrode at a voltage of 1.3 V is 1.10, 0.73, 0.41, and 0.21 A cm at 700 ° C, 650 ° C, 600 ° C, and 550 ° C, respectively. -2 .

[0092] It can be seen that compared with the SBC matrix air electrode material, the SBC+10BFP10 composite air electrode material has excellent electrochemical performance as a single cell of the air electrode in both fuel cell mode and electrolytic cell mode. This is mainly attributed to the fact that the BFP10-coated SBC improves the protonation ability of the air electrode material, increases the catalytic activity, and broadens the three-phase interface of the redox reaction, thereby significantly improving the electrochemical performance of the air electrode material.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A reversible proton ceramic battery composite air electrode material, characterized in that: The composite air electrode material comprises an air electrode matrix material and a coating layer coated on the air electrode matrix material, the air electrode matrix material is a Co-based A-site layered perovskite oxide, and the coating layer material is an Fe-based single perovskite oxide.

2. The composite air electrode material according to claim 1, characterized in that The molecular formula of the air electrode matrix material is LnBaCo2O 5+δ , where Ln = La, Pr, Sm, Gd, and δ is the non-stoichiometric amount of oxygen.

3. The composite air electrode material according to claim 1, characterized in that The molecular formula of the coating material is BaFe 1-y Pr y O 3-δ , the coating layer has a cubic structure, wherein y=0.05~0.2, preferably, y=0.

1.

4. The composite air electrode material according to claim 3, characterized in that: The mass percentage of the coating layer material is 5-20%, and preferably, the mass percentage of the coating layer material is 10%.

5. A method for preparing a composite air electrode material for a reversible proton ceramic battery, characterized in that: The chemical formula of the composite air electrode material is: (1-x)LnBaCo2O 5+δ +xBaFe 1-y Pr y O 3-δ , where Ln = La, Pr, Sm, Gd, δ is the non-stoichiometric amount of oxygen, x = 5 to 20 wt%, y = 0.05 to 0.2, where LnBaCo2O 5+δ As the matrix material, BaFe 1-y Pr y O 3-δ The coating layer is compounded on the base material by at least one of physical vapor deposition method, impregnation method, sol-gel method and mechanical mixing method.

6. The preparation method according to claim 5, characterized in that The LnBaCo2O 5+δ Prepared by the following method: S1: dissolving Ln salt or Ln oxide, Ba salt, and Co salt in dilute nitric acid in a stoichiometric ratio, adding citric acid and ethylenediaminetetraacetic acid as chelating agents, and adjusting the pH to 5-9 by adding ammonia water to obtain a clear solution, placing the obtained clear solution in a water bath at 50-120°C and evaporating it to a gel state; S2: The gel obtained in step S1 is placed in an oven at 50-120°C for 8-12 hours to obtain a dry gel, and the obtained dry gel is heated at 150-300°C until self-propagating combustion is carried out to form fluffy and porous LnBaCo2O 5+δ Precursor powder; S3: Grind the precursor powder obtained in step S2 and remove carbon at 350-600°C for 3-6 hours, then calcine at 900-1150°C for 2-6 hours to obtain LnBaCo2O 5+δ Air electrode matrix material powder.

7. The preparation method according to claim 6, characterized in that The Ln salt is Ln(NO3)3·6H2O, the Ln oxide is Ln2O3, the Ba salt is Ba(NO3)2, and the Co salt is Co(NO3)2·6H2O. The dilute nitric acid is 5-25wt% nitric acid. The molar ratio of the total metal ions in the Ln salt or Ln oxide, and the Co salt to citric acid is 1:1-2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in the Ba salt is 1:1-1.

5.

8. The preparation method according to claim 5, characterized in that Will BaFe 1-y Pr y O 3-δ The method of coating on the base material is: Pr salt, Ba salt, and Co salt were dissolved in deionized water in a stoichiometric ratio, citric acid and ethylenediaminetetraacetic acid were added as chelating agents, and ammonia was added to adjust the pH value to 5-9 to obtain a clear solution. Weigh a certain mass fraction of LnBaCo2O 5+δ The air electrode matrix material is added to the clarified solution, heated and stirred for 2 to 3 hours, and then the solution is ultrasonicated in an ultrasonic device for half an hour, and then the solution is placed in an oven and dried for 1 to 3 hours to obtain a dry gel. The obtained dry gel is heated at 150-300° C. until self-propagating combustion occurs to form a precursor powder of a fluffy and porous composite air electrode material; The obtained precursor powder is ground and then decarbonized at 350-600 ° C for 3-6 hours, and then calcined at 900-1150 ° C for 2-6 hours to obtain the reversible proton ceramic battery composite air electrode material (1-x) LnBaCo2O 5+δ +x BaFe 1-y Pr y O 3-δ Pure phase powder.

9. The preparation method according to claim 8, characterized in that The molar ratio of the total metal ions in the Pr salt and the Co salt to citric acid is 1:1-2, and the molar ratio of Ba ions to ethylenediaminetetraacetic acid in the Ba salt is 1:1-1.

5.

10. A reversible proton ceramic battery, characterized in that: The air electrode material of the reversible proton ceramic battery comprises the air electrode material according to any one of claims 1 to 4.

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