A Cobalt-Free Air Electrode Material for Reversible Proton Conductor Ceramic Electrochemical Batteries and Its Preparation and Application

Abstract

This invention belongs to the field of proton ceramic electrochemical battery technology, and discloses a cobalt-free air electrode material for a reversible proton conductor type ceramic electrochemical battery, its preparation, and its application. The air electrode material has PrBa 0.8‑x Ca 0.2 Fe 1.8 Ce 0.2‑y O 6‑δ The three-phase structure of BaCeO3 and CeO2 forms BaCeO3 and CeO2 nanoparticles attached to PrBa 0.8‑x Ca 0.2 Fe 1.8 Ce 0.2‑y O 6‑δ Heterogeneous structure on the surface of the skeleton; where 0

Description

Technical Field

[0001] This invention belongs to the field of proton ceramic electrochemical battery technology, specifically relating to a cobalt-free air electrode material for a reversible proton conductor type ceramic electrochemical battery, its preparation and application. Background Technology

[0002] The traditional energy structure, dominated by fossil fuels, is rapidly shifting towards a green and low-carbon model based on renewable energy. Due to its wide fuel selectivity, high energy conversion efficiency, and environmental friendliness, reversible protonic ceramic electrochemical cells (R-PCECs) are considered one of the most promising energy storage and conversion technologies. In fuel cell (FC) mode, the chemical energy of various fuels can be directly converted into electrical energy, providing clean secondary energy. In electrolysis cell (EC) mode, intermittent renewable energy sources can be effectively utilized to produce hydrogen or high-value-added carbon-containing fuels, converting intermittent energy into the chemical energy of the fuel for temporary storage, facilitating later transfer and further utilization. In R-PCECs, the slow oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics on the air electrode are the main factors limiting their electrochemical performance. From the most basic conventional materials (such as La...) 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3, Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ From high-activity electrodes (such as PrBa) to highly active electrodes (such as PrBa) 0.5 Sr 0.5 Co 2- x Fe x O 5+δ , and BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δCobalt-based perovskite materials are widely chosen as air electrodes due to their excellent oxygen reduction reaction (ORR) activity. However, cobalt-based materials are chemically unstable and thermally mismatched with commonly used proton-conducting electrolytes, potentially leading to severe activity degradation during long-term operation. Furthermore, the rapidly increasing demand for cobalt-based compounds in lithium-ion batteries has increased the cost of cobalt. These factors limit the practical application of cobalt-based air electrodes. Therefore, developing cobalt-free air electrodes with high activity and stability has become a key challenge. Summary of the Invention

[0003] To overcome the shortcomings and deficiencies of existing technologies, the purpose of this invention is to provide a cobalt-free air electrode material for reversible proton-conducting ceramic electrochemical batteries, as well as its preparation and application. The air electrode material of this invention has BaCeO3 and CeO2 nanoparticles coated on PrBa... 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ The heterogeneous structure on the surface of the (PBCFC) framework provides more reaction sites for ORR or OER. This invention applies this material to the air electrode of a reversible proton ceramic electrochemical cell, achieving high power density (cell mode) / current density (electrolysis mode) and excellent long-term operational stability.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A reversible proton conductor type ceramic electrochemical cell air electrode material with PrBa 0.8- x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ The three-phase structure of BaCeO3 and CeO2 forms a structure in which BaCeO3 and CeO2 nanoparticles are coated on PrBa 0.8-x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ The heterogeneous structure of the skeleton surface (PBCFC); where 0 < x < 0.8, 0 < y < 0.2; 0 < δ < 1, and δ is the oxygen vacancy content.

[0006] The preparation method of the air electrode material for the reversible proton ceramic electrochemical cell includes the following steps: praseodymium nitrate, barium nitrate, calcium nitrate, iron nitrate, and cerium nitrate are prepared according to the molecular formula PrBa 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δThe stoichiometric ratio was prepared by the sol-gel method to obtain the air electrode material.

[0007] Specifically, the steps include the following:

[0008] Praseodymium nitrate, barium nitrate, calcium nitrate, ferric nitrate, and cerium nitrate were classified according to the molecular formula PrBa. 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ The stoichiometric ratio of citric acid monohydrate and ethylenediaminetetraacetic acid (EDTA) is dissolved in water to obtain a nitrate solution. Citric acid monohydrate and EDTA are dissolved in ammonia water to form a clear solution, thus obtaining a mixed solution. The mixed solution of citric acid monohydrate, EDTA, and ammonia water is then added to the nitrate solution, and the pH of the solution is adjusted to 7-8 by adding ammonia water. The solution is continuously heated and stirred until homogeneous, and after the water has fully evaporated, a homogeneous gel-like substance is obtained. The gel-like substance is then heated and calcined to obtain the desired air electrode material.

[0009] The molar ratio of the total metal ions of Pr, Ba, Ca, Fe, and Ce to citric acid monohydrate to ethylenediaminetetraacetic acid is (0.5-1.5):(1.5-2.5):(0.5-1.5).

[0010] The temperature of the continuous heating is 130-160℃;

[0011] The stirring speed is 250-300 r / min;

[0012] The conditions for heat treatment of the gel-like substance are: 250-280℃ for 2-5 hours;

[0013] The calcination temperature is 900-1000℃, and the calcination time is 2-5 hours.

[0014] The above-mentioned air electrode material is used in reversible proton ceramic electrochemical cells. The application refers to its use as an air electrode in reversible proton ceramic electrochemical cells.

[0015] Specifically, the process includes the following steps: mixing air electrode material, ethyl cellulose, and terpineol to obtain the desired PBCFC air electrode slurry; uniformly printing the slurry onto a half-cell supported by a fuel electrode, drying, and calcining to obtain a reversible proton ceramic electrochemical cell with a PBCFC porous air electrode.

[0016] The mass ratio of the air electrode powder to ethyl cellulose to terpineol is (0.5-2):(0.02-0.08):(0.38-1.52).

[0017] The drying temperature is 60-90℃.

[0018] The calcination temperature is 900-1000℃, and the calcination time is 2-5 hours.

[0019] The half-cell supported by the fuel electrode includes a fuel electrode and an electrolyte; the fuel electrode is disposed on one side of the electrolyte. An air electrode paste is printed on the other side of the electrolyte.

[0020] The reversible proton-conducting ceramic electrochemical cell of the present invention is prepared by co-casting and its structure sequentially includes a fuel electrode, an electrolyte, and an air electrode. The air electrode is the aforementioned PBCFC electrode. The electrolyte is BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb). The fuel electrode is a composite electrode composed of NiO and BZCYYb in a mass ratio of (6-7):(4-3).

[0021] This invention is based on PrBa 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ Raw materials were prepared in stoichiometric proportions and then self-assembled into PrBa after calcination via the sol-gel method. 0.8-x Ca0.2Fe 1.8 Ce 0.2-y O 6-δ The three-phase structure of BaCeO3 and CeO2 forms a heterostructure in which BaCeO3 and CeO2 nanoparticles are attached to the framework surface (PBCFC).

[0022] This invention evaluates the phase structure, chemical compatibility, electrochemical performance, and hydrogen production and Faraday efficiency of the air electrode material under electrolysis mode. The air electrode material of this invention exhibits a stable phase structure, good chemical compatibility, high power density and electrolysis current, superior battery stability, and reasonable hydrogen production and Faraday efficiency under electrolysis mode.

[0023] The present invention has the following beneficial effects:

[0024] The cobalt-free air electrode material PBCFC for reversible proton conductor ceramic electrochemical batteries involved in this invention is prepared by the sol-gel method and has a stable phase structure, good chemical compatibility, high power density and electrolysis current, superior battery stability, and reasonable hydrogen production and Faraday efficiency under electrolysis mode.

[0025] (1) The preparation method is simple

[0026] A simple sol-gel method was used to synthesize heterostructured perovskite PBCFCs coated with BaCeO3 and CeO2 nanoparticles in one step, which is simple and efficient.

[0027] (2) Good chemical compatibility

[0028] Compatibility analysis showed that the prepared PBCFC air electrode and the proton-conduction-based BZCYYb electrolyte did not undergo significant chemical reactions under the actual operating conditions of the electrochemical cell.

[0029] (3) Excellent electrochemical performance

[0030] The reversible proton ceramic electrochemical cell Ni-BZCYYb|BZCYYb|PBCFC with PBCFC as the air electrode achieved maximum output power of 1.6, 1.04, and 0.57 W / cm² at 700, 650, and 600 °C, respectively, in fuel cell mode. -2 In electrolytic cell mode, the electrolytic current densities at 700, 650, and 600°C and a voltage of 1.3V reached 3.56, 2.45, and 1.36 A cm⁻¹, respectively. -2 Furthermore, the single cell exhibits good stability in fuel cell mode, electrolysis mode, and reversible mode. At 650℃ and a water content of 10%, with a current density of +0.5 A cm⁻¹, -2 At that time, the Faraday efficiency of water electrolysis was ~85.16%, and the hydrogen production rate was ~2.97 ml / min. -1 cm -2 When the current density is +0.75 Acm -2 At that time, the Faraday efficiency of water electrolysis was ~59.55%, and the hydrogen production rate was ~3.11 ml / min. -1 cm -2 . Attached Figure Description

[0031] Figure 1 SEM image of the PBCFC powder prepared in Example 1;

[0032] Figure 2 XRD pattern and refined spectrum of PBCFC powder prepared in Example 1;

[0033] Figure 3 TEM image of the PBCFC powder prepared in Example 1;

[0034] Figure 4 The XRD pattern of PBCFC powder and BZCYYb electrolyte powder prepared in Example 1 after being mixed evenly at a mass ratio of 1:1 and calcined at 950°C for 2 hours.

[0035] Figure 5The symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared in Example 3, using PBCFC as the air electrode and BZCYYb as the electrolyte, was tested at 50 mL / min. -1 Polarization impedance spectra of humidified air containing 3% water vapor at a flow rate in the temperature range of 700-500℃.

[0036] Figure 6 The activation energy curve was calculated from the polarization impedance spectrum results of the symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared in Example 3, which used PBCFC as the air electrode and BZCYYb as the electrolyte, within a temperature range of 700-500℃.

[0037] Figure 7 The symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared in Example 3, using PBCFC as the air electrode and BZCYYb as the electrolyte, was tested at 50 mL / min. -1 The polarization impedance stability was tested at 650°C for 100 hours under humidified air containing 3% water vapor at a flow rate of [missing information].

[0038] Figure 8 In Example 4, a fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) was prepared using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode in battery mode within a temperature range of 700-600°C (30 mL / min was introduced into the fuel electrode side). -1 The impedance spectrum was measured under conditions of humidified hydrogen gas containing 3% water vapor by volume, with ambient air on the air electrode side.

[0039] Figure 9 In Example 4, a fuel electrode-supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) was prepared using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode in fuel cell mode within a temperature range of 700-600℃ (30 mL / min was introduced into the fuel electrode side). -1 The IVP curve was tested under conditions of humidified hydrogen containing 3% water vapor (with ambient air on the air electrode side);

[0040] Figure 10 The fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared in Example 4, using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode, was tested at 650°C in fuel cell mode (30 mL / min was introduced into the fuel electrode side). -1The stability test was conducted for 65 hours under humidified hydrogen containing 3% water vapor (with ambient air on the air electrode side).

[0041] Figure 11 The fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared in Example 4, using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode, was electrolyzed in a battery mode within a temperature range of 700-600℃ (30 mL / min was introduced into the fuel electrode side). -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 The IV curve was tested under humidified air containing 3% water vapor by volume.

[0042] Figure 12 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared in Example 4, using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode, was electrolyzed at 650°C in a 30 mL / min solution on the fuel electrode side. -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 The stability test was conducted over 95 hours in humidified air containing 3% water vapor by volume.

[0043] Figure 13 The fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared by using PBCFC as air electrode, BZCYYb as electrolyte, and Ni-BZCYYb as fuel electrode in Example 4 was subjected to a 200-hour stability test of cyclic operation at 600°C in fuel cell mode and electrolytic cell mode.

[0044] Figure 14 The fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared in Example 4, using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode, was tested at 650°C with a current of 0.5 A cm⁻¹. -2 0.75A cm -2 and 1A cm -2 The electrolysis current density, Faraday efficiency during water electrolysis, and the rate of hydrogen production during water electrolysis;

[0045] Figure 15The SEM images of the cross section and the surface of the air electrode of the fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared by PBCFC as air electrode, BZCYYb as electrolyte, and Ni-BZCYYb as fuel electrode in Example 4 after stability testing; where (a) is the cross section SEM image of the single cell after stability testing, and (b) is the SEM image of the surface of the air electrode after stability testing.

[0046] Figure 16 A symmetrical cell (PBCF|BZCYYb|PBCF) prepared using PBCF as the air electrode and BZCYYb as the electrolyte in Example 2 was tested at 30 mL / min. -1 Polarization impedance spectra of humidified air containing 3% water vapor at a flow rate in the temperature range of 700-500℃.

[0047] Figure 17 A comparison of activation energy curves obtained by fitting polarization impedance spectra of symmetric cells prepared from the electrode powders of Examples 1 and 2 in the temperature range of 700-500℃. Detailed Implementation

[0048] The present invention will be described in further detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0049] Example 1

[0050] This embodiment provides a cobalt-free air electrode material (nominal composition: PrBa) for a reversible proton conductor type ceramic electrochemical battery. 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ The preparation method of ) specifically includes the following steps:

[0051] 1) According to PrBa 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ According to the stoichiometric ratio, weigh 8.700g of praseodymium nitrate, 4.181g of barium nitrate, 0.945g of calcium nitrate, 12.928g of ferric nitrate, and 3.474g of cerium nitrate, add 100mL of deionized water, and heat and stir until completely dissolved.

[0052] 2) Weigh out 33.622 g of citric acid monohydrate and 26.896 g of ethylenediaminetetraacetic acid as complexing agents according to the molar ratio of total metal ions of Pr, Ba, Ca, Fe, Ce: citric acid monohydrate: ethylenediaminetetraacetic acid of 1:2:1. Add them to 80 mL of ammonia water and stir until dissolved. Then add the solution containing the complexing agent to the solution containing the metal nitrates, and add an appropriate amount of ammonia water (about 80 mL) dropwise to adjust the pH of the solution to between 7 and 8.

[0053] 2) The mixed solution is heated at a constant temperature of 160℃ and continuously stirred at a speed of 250r / min until the water is completely evaporated and a gel-like substance is formed;

[0054] 3) The gel-like substance was placed in an oven and heated to 280°C for self-ignition, and kept at that temperature for 2 hours to dry it thoroughly, resulting in a fluffy air electrode material precursor powder;

[0055] 4) The air electrode precursor powder was calcined in a muffle furnace at 1000°C for 2 hours to obtain the desired PBCFC air electrode powder. This embodiment prepares an air electrode material with a heterogeneous structure.

[0056] Example 2

[0057] This embodiment provides a single-phase air electrode material PrBa 0.8 Ca 0.2 Fe2O 6-δ The preparation method specifically includes the following steps:

[0058] 1) Weigh 8.700g of praseodymium nitrate, 4.181g of barium nitrate, 0.945g of calcium nitrate, and 16.160g of ferric nitrate, and dissolve them completely in deionized water.

[0059] 2) Weigh out 33.622 g of citric acid monohydrate and 26.896 g of ethylenediaminetetraacetic acid as complexing agents according to the molar ratio of total metal ions of Pr, Ba, Ca, and Fe to citric acid monohydrate to ethylenediaminetetraacetic acid of 1:2:1. Add them to 80 ml of ammonia water and stir until dissolved. Then add the solution containing the complexing agent to the solution containing the metal nitrates and add an appropriate amount of ammonia water to adjust the pH of the solution to between 7 and 8.

[0060] 2) The mixed solution is heated at a constant temperature of 160℃ and continuously stirred at a speed of 250r / min until the water is completely evaporated and a gel-like substance is formed;

[0061] 3) The gel-like substance was placed in an oven and heated to 280°C for self-ignition, and kept at that temperature for 2 hours to dry it thoroughly, resulting in a fluffy air electrode material precursor powder;

[0062] 4) The air electrode precursor powder was calcined in a muffle furnace at 1000℃ for 2 hours to obtain PrBa. 0.8 Ca 0.2 Fe2O 6-δ Air electrode powder.

[0063] Example 3

[0064] This embodiment provides a method for preparing a symmetrical battery using PBCFC powder from Example 1 as an air electrode. The symmetrical battery adopts an "air electrode|electrolyte|air electrode" structure, namely "PBCFC|BZCYYb|PBCFC", and specifically includes the following steps:

[0065] 1) Weigh 1g of the PBCFC air electrode powder prepared in Example 1, and weigh 0.04g of ethyl cellulose and 0.76g of terpineol in a mortar and grind them for 1h to prepare PBCFC air electrode slurry according to the mass ratio of powder: ethyl cellulose: terpineol of 1: 0.04: 0.76.

[0066] 2) BZCYYb powder was pressed into discs with a diameter of 10 mm under a pressure of 5 MPa and then calcined at 1450℃ for 5 h.

[0067] 3) The air electrode slurry was screen-printed twice onto both sides of a calcined and dense BZCYYb electrolyte sheet. After each side was coated, it was dried in an oven at 70°C for 1 hour, followed by calcination at 950°C for 2 hours in air to form a porous PBCFC air electrode with an effective active area of ​​0.2826 cm². 2 A well-prepared symmetrical cell was obtained; its polarization impedance spectrum was then tested under humid air conditions within a temperature range of 700-500℃. The polarization impedance of the symmetrical cell at 700℃ was 0.10 Ωcm. 2 .

[0068] Example 4

[0069] This embodiment provides a method for preparing a single cell using the PBCFC powder from Example 1 as the air electrode. The single cell adopts a "fuel electrode|electrolyte|air electrode" structure, namely "Ni-BZCYYb|BZCYYb|PBCFC", and specifically includes the following steps:

[0070] 1) Weigh the PBCFC air electrode powder obtained in Example 1, and weigh 0.04g of ethyl cellulose and 0.76g of terpineol in a mortar and grind them for 1h to prepare PBCFC air electrode slurry, according to the mass ratio of powder: ethyl cellulose: terpineol of 1: 0.04: 0.76.

[0071] 2) The fuel electrode supported half-cell Ni-BZCYYb|BZCYYb was prepared into a disc with a diameter of 15 mm by co-casting, degreased at 600℃ for 2 h, and then calcined at 1450℃ for 5 h; the mass ratio of NiO to BZCYYb in the fuel electrode of the fuel electrode supported half-cell Ni-BZCYYb|BZCYYb is 6:4.

[0072] 3) The air electrode slurry was screen-printed onto the surface of the BZCYYb electrolyte, dried in an oven at 70℃ for 1 hour, and then sintered at 950℃ for 2 hours in air to form a porous PBCFC air electrode with an effective active area of ​​0.196 cm². 2 The prepared single cell was obtained and used for testing its output power and electrolytic current within a temperature range of 700-600℃. The maximum output power of the cell at 700℃ was 1.60 W / cm². -2 The electrolytic current density at a voltage of 1.3V reached 3.56A / cm². -2 .

[0073] Example 5

[0074] This embodiment provides a test method for the symmetrical battery in Embodiment 3:

[0075] The symmetric cell prepared in Example 3 was used in a PARSTAT MC200 electrochemical workstation at 50 mL / min. -1 Polarization impedance was tested in humidified air containing 3% water vapor at a flow rate of [value missing] within a temperature range of 700-500°C. Under open-circuit voltage conditions, a stimulation voltage of 40mV was applied at 50°C intervals from 1MHz to 0.01Hz within the 700-500°C temperature range. The test results of polarization impedance are as follows: Figure 5 As shown. The polarization impedance is rearranged into an Arrhenius curve, as shown below. Figure 6 As shown.

[0076] The symmetric cell prepared in Example 3 was used in a PARSTAT MC200 electrochemical workstation at 50 mL min- 1 The polarization impedance stability was tested at 650°C under humidified air containing 3% water vapor at a flow rate of [missing value]. Under open-circuit voltage conditions, a stimulation voltage of 40mV was applied from 1MHz to 0.01Hz. The test results are as follows: Figure 7 As shown.

[0077] Example 6

[0078] This embodiment provides a method for testing a single cell in fuel cell mode as described in Embodiment 4:

[0079] The impedance spectra of the single cells prepared in Example 4 were measured using a PARSTAT MC200 electrochemical workstation in the temperature range of 700-600°C. 30 mL of [unspecified substance] was introduced into the fuel electrode side. -1 The test used humidified hydrogen gas containing 3% water vapor by volume, with ambient air on the air electrode side. Under open-circuit voltage conditions, a stimulation voltage of 40mV was applied at 50°C intervals from 1MHz to 0.1Hz within a temperature range of 700-600°C. The test results are as follows: Figure 8 As shown.

[0080] The IVP curves of the single cell prepared in Example 4 were tested using a PARSTAT MC200 electrochemical workstation within a temperature range of 700-600°C. 30 mL of [unspecified substance] was introduced into the fuel electrode side. -1 The test used humidified hydrogen gas containing 3% water vapor by volume, with ambient air on the air electrode side. The test results are as follows: Figure 9 As shown.

[0081] The single cell prepared in Example 4 was used on a PARSTAT MC200 electrochemical workstation at 650°C and -0.5A cm⁻¹. -2 Stability tests of the fuel cell mode were conducted at a current density of 30 mL / min. -1 The test used humidified hydrogen gas containing 3% water vapor by volume, with ambient air on the air electrode side. The test results are as follows: Figure 10 As shown.

[0082] Example 7

[0083] This embodiment provides a method for testing a single cell in electrolytic battery mode as described in Embodiment 4:

[0084] The single cell prepared in Example 4 was tested using a PARSTAT MC200 electrochemical workstation within a temperature range of 700-600°C, and its IV curve was measured. 30 mL of [unspecified substance] was introduced into the fuel electrode side. -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 Humidified air containing 3% water vapor by volume. Test results are as follows: Figure 11 As shown.

[0085] The prepared single cells were tested using a PARSTAT MC200 electrochemical workstation at 650 °C and +0.5 A cm⁻¹. -2 Stability tests were conducted in electrolytic cell mode at a current density of 30 mL / min. -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 Humidified air containing 3% water vapor by volume. Test results are as follows: Figure 12 As shown.

[0086] Example 8

[0087] This embodiment provides a test method for the single cell in Embodiment 4 to cycle in fuel cell mode and electrolysis battery mode:

[0088] The single cell prepared in Example 4 was tested at 600°C using a PARSTAT MC200 electrochemical workstation with an external voltage of ±0.5 Acm. -2 At a current density of [value missing], the battery was switched every two hours, alternating between fuel cell mode and electrolysis cell mode, to test its cycle stability for 200 hours. 30 mL of [unclear text - possibly a typo, should be "min-"] was introduced into the fuel electrode side. 1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 Humidified air containing 3% water vapor by volume. Test results are as follows: Figure 13 As shown.

[0089] Characterization results

[0090] (1) SEM characterization

[0091] Figure 1 The image shows a SEM image of the air electrode powder prepared in Example 1. It can be seen that the air electrode powder prepared in Example 1 self-assembled into a bulk phase and surface-precipitated nanoparticles during the powder calcination process.

[0092] (2) XRD characterization

[0093] Figure 2 The XRD pattern of the air electrode powder prepared in Example 1 at room temperature is shown. XRD refinement reveals that the electrode powder prepared in Example 1 contains approximately 89.65 wt% perovskite PrBa. 0.8-x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-8 Phase (space group is) Cell parameters are ), 5.76% perovskite BaCeO3 phase (space group ), Cell parameters are ) and 4.59% CeO2 phase (space group ) Cell parameters are )

[0094] (3) TEM characterization

[0095] Figure 3 This is a TEM image of the air electrode powder prepared in Example 1. From... Figure 3As can be seen from the text, the air electrode powder prepared in Example 1 has a heterostructure (PBCFC) consisting of a host phase and a surface-precipitated nanoparticle phase. The interplanar spacings of 0.391 nm and 0.225 nm in the host phase correspond to PrBa 0.8-x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ The 001 and 111 crystal planes, with interplanar spacing of 0.31 nm and 0.27 nm for the surface nanoparticles, correspond to the 001 and 002 crystal planes of BaCeO3 and CeO2, respectively.

[0096] (4) Characterization of chemical compatibility

[0097] Figure 4 The image shows the XRD pattern of a mixture of PBCFC powder (i.e., the air electrode powder prepared in Example 1) and BZCYYb electrolyte powder at a mass ratio of 1:1, followed by calcination at 950°C for 2 hours. From... Figure 4 As can be seen from the data, after high-temperature calcination, the mixed powder did not exhibit any peaks other than those of PBCFC and BZCYYb, indicating that the PBCFC air electrode powder and the BZCYYb electrolyte have good chemical compatibility.

[0098] (6) Impedance and activation energy characterization of symmetrical cells

[0099] Figure 5 A symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared using PBCFC as the air electrode and BZCYYb as the electrolyte (the cell prepared in Example 3) was tested at 50 mL / min. -1 Polarization impedance spectra were obtained in the temperature range of 700–500 °C under humidified air containing 3% water vapor at a flow rate of [value missing]. The polarization impedances at 700, 650, 600, 550, and 500 °C were 0.16, 0.42, 1.09, and 3.38 Ωcm, respectively. 2 .

[0100] Figure 6 The activation energy curves were obtained by fitting the polarization impedance spectra of a symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared with PBCFC as the air electrode and BZCYYb as the electrolyte (the cell prepared in Example 3) within a temperature range of 700-500℃. The activation energy of the PBCFC air electrode was 1.34 eV.

[0101] Figure 7 A symmetrical cell (PBCFC|BZCYYb|PBCFC) prepared with PBCFC as the air electrode and BZCYYb as the electrolyte was tested at 50 mL / min. -1The polarization impedance stability was tested at 650℃ for 100 h under humidified air containing 3% water vapor at a flow rate of [value missing]. The figure shows that the PBCFC air electrode material exhibits good electrochemical stability.

[0102] (7) Electrochemical performance characterization of single cells in fuel cell mode

[0103] Figure 8 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., a reversible proton ceramic electrochemical cell) was tested in fuel cell mode within a temperature range of 700-600℃ (30 mL / min was introduced into the fuel electrode side). -1 Impedance spectra were measured using humidified hydrogen gas containing 3% water vapor (with ambient air as the air electrode side). The ohmic impedances of the single cell were 0.070, 0.10, and 0.14 Ωcm at 700, 650, and 600 °C, respectively. 2 The polarization impedances are 0.038, 0.093, and 0.266 Ωcm, respectively. 2 .

[0104] Figure 9 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., a reversible proton ceramic electrochemical cell) was tested in fuel cell mode within a temperature range of 700-600℃ (30 mL / min was introduced into the fuel electrode side). -1 The IVP curves were measured under conditions of humidified hydrogen gas containing 3% water vapor (with ambient air as the air electrode side). The results show that the single cell using a PBCFC as the air electrode achieves maximum output power of 1.6, 1.04, and 0.57 W / cm² at 700, 650, and 600 °C, respectively. -2 .

[0105] Figure 10 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., the reversible proton ceramic electrochemical cell) was tested at 650°C in fuel cell mode (30 mL / min flow to the fuel electrode side). -1 Humidified hydrogen gas containing 3% water vapor by volume (ambient air on the air electrode side) at -0.5 A cm -2A 65-hour stability test was conducted at the specified current density. The results showed that the battery maintained stable operation for 65 hours with minimal performance degradation, indicating the excellent overall fabrication process of the single cell. The PBCFC air electrode also exhibited excellent electrochemical performance in battery mode.

[0106] (8) Electrochemical performance characterization of single cells in electrolytic cell mode

[0107] Figure 11 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., a reversible proton ceramic electrochemical cell) was electrolyzed in a temperature range of 700-600℃ (30 mL / min) on the fuel electrode side. -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 100 mL / min. -1 The IV curves were tested under humidified air containing 3% water vapor by volume. The results show that the single cell with PBCFC as the air electrode achieves electrolytic current densities of 3.56, 2.45, and 1.36 A cm⁻¹ at 700, 650, and 600 °C and a voltage of 1.3 V in electrolysis mode, respectively. -2 .

[0108] Figure 12 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., a reversible proton ceramic electrochemical cell) was tested at 650°C in electrolytic cell mode (30 mL of fuel was introduced into the fuel electrode side). -1 Humidified hydrogen gas containing 3% water vapor was introduced into the air electrode side at a rate of 50 mL / min. -1 (And humidified air containing 3% water vapor by volume) at +0.5A cm -2 A 95-hour stability test was conducted at the specified current density. The results show that the single cell using the PBCFC air electrode can operate stably in electrolysis mode with almost no performance degradation.

[0109] Figure 13The stability of a fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared using PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., the reversible proton ceramic electrochemical cell) was tested for 200 hours at 650°C in fuel cell mode and electrolytic cell mode. The results showed that the single cell using the PBCFC air electrode could still maintain good stability in both modes of cyclic operation, indicating that PBCFC is a highly active and stable air electrode.

[0110] (9) Characterization of Faraday efficiency in water electrolysis

[0111] Figure 14 A fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., the reversible proton ceramic electrochemical cell) was tested at 650°C with a current of 0.5 A cm⁻¹. -2 0.75A cm -2 and 1A cm -2 The electrolysis current density, Faraday efficiency, and hydrogen production rate during water electrolysis are calculated. Under 10% water pressure conditions, the electrolysis current density is +0.5 A cm⁻¹. -2 and +0.75Acm -2 The Faraday efficiencies during water electrolysis were ~85.16% and ~59.55%, respectively, and the hydrogen production rates were ~2.97 ml / min. -1 cm -2 and ~3.11ml min -1 cm -2 .

[0112] (10) SEM characterization

[0113] Figure 15 SEM images of the cross-section and air electrode surface of a fuel electrode supported single cell (Ni-BZCYYb|BZCYYb|PBCFC) prepared with PBCFC as the air electrode, BZCYYb as the electrolyte, and Ni-BZCYYb as the fuel electrode (the single cell prepared in Example 4, i.e., a reversible proton ceramic electrochemical cell) after stability testing; where (a) is the cross-sectional SEM image of the single cell after stability testing, and (b) is the SEM image of the air electrode surface of the single cell after stability testing. Figure 15 As can be seen, after testing, the fuel electrode, electrolyte, and air electrode are all tightly bound together, and the nanoparticles on the surface of the PBCFC air electrode are stably present. This is a prerequisite for the excellent electrochemical performance of single cells and symmetric cells.

[0114] (11) The performance of symmetrical cells made from the electrode powder prepared in Example 2 and the electrode powder prepared in Example 1 was compared.

[0115] The electrode powder PrBa from Example 2 0.8 Ca 0.2 Fe2O 6-δ (Note: PBCF) and the electrode powder PBCFC prepared in Example 1 were used to prepare a symmetrical cell (preparation method is the same as in Example 3) and tested. The results are as follows: Figure 16 As shown in Figure 17. In Example 1, the performance of the two-phase heterostructure air electrode material PBCFC was superior to that of PBCF.

[0116] Figure 16 A symmetrical cell (PBCF|BZCYYb|PBCF) was prepared using PBCF as the air electrode and BZCYYb as the electrolyte. The cell was tested in 50 mL min. -1 Polarization impedance spectra were obtained in the temperature range of 700–500 °C under humidified air containing 3% water vapor at a flow rate of [value missing]. The polarization impedances at 700, 650, 600, 550, and 500 °C were 0.16, 0.42, 1.09, 3.38, and 11.48 Ωcm, respectively. 2 .

[0117] Figure 17 A comparison of activation energy curves obtained by fitting polarization impedance spectra of symmetric cells prepared from the electrode powders of Examples 1 and 2 in the temperature range of 700-500°C. The activation energy of the PBCFC air electrode (1.34 eV) is lower than that of the PBCF air electrode (1.37 eV).

Claims

1. A cobalt-free air electrode material for a reversible proton conductor type ceramic electrochemical battery, characterized in that: With PrBa 0.8- x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ , a three-phase structure of BaCeO3 and CeO2, forming a heterostructure where BaCeO3 and CeO2 nanoparticles adhere to the surface of the PrBa 0.8- x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ skeleton; where 0 < x < 0.8, 0 < y < 0.8; 0 < δ < 1, and δ is the oxygen vacancy content; PrBa 0.8-x Ca 0.2 Fe 1.8 Ce 0.2-y O 6-δ BaCeO3 and CeO2 have the molecular formula PrBa 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ .

2. The method for preparing the cobalt-free air electrode material for the reversible proton conductor type ceramic electrochemical cell according to claim 1, characterized in that: The process includes the following steps: mixing praseodymium nitrate, barium nitrate, calcium nitrate, ferric nitrate, and cerium nitrate according to PrBa 0.8 Ca 0.2 Fe 1.8 Ce 0.2 O 6-δ The stoichiometric ratio of the solution is added to water to dissolve it; a mixed solution of citric acid monohydrate, ethylenediaminetetraacetic acid, and ammonia is added; the pH of the solution is adjusted to 7-8 using ammonia; the solution is continuously heated and stirred until it is homogeneous, and a gel-like substance is obtained after the water has fully evaporated; the gel-like substance is then heated and calcined to obtain the desired air electrode material.

3. The method for preparing the cobalt-free air electrode material for the reversible proton conductor type ceramic electrochemical cell according to claim 2, characterized in that: The molar ratio of total metal ions of Pr, Ba, Ca, Fe, and Ce to citric acid monohydrate to ethylenediaminetetraacetic acid is (0.5-1.5):(1.5-2.5):(0.5-1.5). The adjustment of pH to 7-8 refers to adjusting the pH value to 7-8 by adding ammonia water dropwise. The temperature of the continuous heating is 130-160℃; The stirring speed is 250-300 r / min; The conditions for heat treatment of the gel-like substance are: 250-280℃ for 2-5 hours; The calcination temperature is 900-1000℃, and the calcination time is 2-5 hours.

4. The application of the cobalt-free air electrode material of the reversible proton conductor type ceramic electrochemical cell according to claim 1 in the preparation of reversible proton ceramic electrochemical cells.

5. The application according to claim 4, characterized in that: The cobalt-free air electrode material for the reversible proton conductor type ceramic electrochemical battery is used to prepare the air electrode in the reversible proton ceramic electrochemical battery.

6. The application according to claim 5, characterized in that: The reversible proton conductor type ceramic electrochemical cell structure includes a fuel electrode, an electrolyte, and an air electrode in sequence; the fuel electrode and the air electrode are disposed on both sides of the electrolyte; the air electrode is prepared from the cobalt-free air electrode material of the reversible proton conductor type ceramic electrochemical cell as defined in claim 1.

7. The application according to claim 6, characterized in that: The electrolyte is BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ ; 0 < δ < 1, where δ is the oxygen vacancy content; The fuel electrode is NiO and BaZr. 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ A composite electrode composed of a mass ratio of (6-7):(4-3).

8. The application according to claim 5 or 6, characterized in that: The air electrode is prepared by the following method: mixing air electrode material, ethyl cellulose and terpineol to obtain PBCFC air electrode slurry; printing the air electrode slurry onto the electrolyte of a half-cell supported by a fuel electrode, drying and calcining to obtain a reversible proton ceramic electrochemical cell with a PBCFC porous air electrode.

Images