A low-temperature ceramic fuel cell composite cathode and a low-temperature ceramic fuel cell

Abstract

The application relates to a low-temperature ceramic fuel cell composite cathode and a low-temperature ceramic fuel cell, wherein the cathode is composed of two kinds of 'oxygen ion / proton / electron' mixed conduction type electrodes Ba 0.9 Co 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3‑δ (BCFZY) and Ni 0.8 Co 0.15 Al 0.05 LiO 2‑δ (NCAL) are compounded. The NCAL is introduced into the BCFZY by a simple and easy solid-phase mixing method, the ion conductivity and catalytic activity of the composite cathode are optimized by a component regulation method, the composite cathode is applied to a BCFZY-ZnO electrolyte ceramic fuel cell, and good low-temperature output performance can be obtained. Compared with the single-phase cathode BCFZY, the composite cathode has better low-temperature oxygen ion conductivity and oxygen reduction catalytic activity, and therefore has important application prospects in a low-temperature ceramic fuel cell system.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, and in particular to a low-temperature ceramic fuel cell composite cathode and a low-temperature ceramic fuel cell. Background Technology

[0002] Ceramic fuel cells, also known as solid oxide fuel cells (SOFCs), are power generation devices that directly convert the chemical energy of fuels, primarily hydrogen, into electrical energy. Because they bypass the traditional Carnot cycle of heat engines, their theoretical efficiency can reach 60%, and they possess advantages such as high energy conversion efficiency, low pollution, and fuel versatility. Therefore, ceramic fuel cells have gradually become a key focus and hot topic in the field of new energy in recent years.

[0003] However, the electrolytes of traditional ceramic fuel cells typically need to operate at high temperatures of 800–1000°C, and their cathodes also suffer from very high polarization losses at low temperatures, leading to excessively high battery costs, shortened battery life, and significant limitations on their applications. Solving these problems to reduce the operating temperature of the battery has become a major development direction for the commercialization of SOFCs. Summary of the Invention

[0004] To address the aforementioned issues, a low-temperature ceramic fuel cell composite cathode and a low-temperature ceramic fuel cell are provided, aiming to effectively solve the problems existing in SOFC batteries.

[0005] The specific technical solution is as follows:

[0006] The first aspect of this invention is to provide a method for preparing a low-temperature ceramic fuel cell composite cathode, characterized by comprising the following steps:

[0007] 1) Weigh out the metal ions nitrate and citric acid in a molar ratio of total metal ions: citric acid = 2:3, add them to deionized water to prepare a 150 mL solution, and then heat the solution to 50 °C with stirring for later use.

[0008] 2) Weigh EDTA in an equimolar ratio to the total amount of metal ions, and prepare a 100 mL solution with saturated ammonia water to obtain an EDTA solution; add the EDTA solution to the solution in step 1), and then slowly add saturated ammonia water dropwise until the pH of the solution reaches 8-9. Heat the solution to 110°C with stirring, and stop stirring when the liquid forms a gel to obtain BCFZY(Ba 0.9 Co 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ Precursor;

[0009] 3) Dry the BCFZY precursor at 130℃ until the liquid is completely evaporated, grind it, then sinter the material in a muffle furnace at 400℃ for 2 hours, grind it, then calcine the material in a muffle furnace at 1100℃ for 8 hours, grind the material to the nanoscale, and obtain BCFZY single-phase cathode powder.

[0010] 4) NCA (Ni 0.8 Co 0.15 Al 0.05 LiO 2-δ Grind evenly, mix the BCFZY powder and NCAL powder prepared in step 3), use ethanol as a dispersant, and grind thoroughly in a mortar.

[0011] 5) The mixture after grinding in step 4) is sintered in air at 600°C for 2 hours, and then further ground in a mortar to obtain a low-temperature ceramic fuel cell composite cathode.

[0012] Specifically, in step 1), the metal ion nitrate is one or more of barium nitrate, cobalt nitrate, iron nitrate, zirconium nitrate, or yttrium nitrate.

[0013] A second aspect of the present invention is to provide a low-temperature ceramic fuel cell composite cathode prepared according to the above-described preparation method.

[0014] In this invention, the composite cathode is composed of two typical "oxygen ion / proton / electron" mixed conductive electrodes, BCFZY and NCAL, wherein BCFZY has the chemical formula Ba. 0.9 Co 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ For ABO 3-δ Type 1 perovskite structure solid oxide, NCAL chemical formula is Ni 0.8 Co 0.15 Al 0.05 LiO 2-δ For ABO 2-δ A layered solid oxide, where δ represents the oxygen vacancy that causes the substance to maintain electroneutrality.

[0015] A third aspect of the present invention is to provide a low-temperature ceramic fuel cell comprising the above-described low-temperature ceramic fuel cell composite cathode.

[0016] A fourth aspect of the present invention is to provide a method for assembling the above-mentioned low-temperature ceramic fuel cell, characterized by comprising the following steps:

[0017] 1) Mix NCAL powder and terpineol thoroughly at a mass ratio of 3:1, grind them, then coat the material evenly on nickel foam, dry it, and make NCAL-Ni anode sheet;

[0018] 2) Mix BCFZY powder and ZnO nanopowder at a mass ratio of 2:1, add an appropriate amount of alcohol and grind evenly, and sinter at 700℃ for 2h to obtain BCFZY-ZnO electrolyte powder sample.

[0019] 3) The composite cathode material BCFZY-NCAL was mixed with carbon powder at a mass ratio of 9:1 to obtain BCFZY-NCAL-C cathode powder;

[0020] 4) Weigh 0.3g of BCFZY-ZnO electrolyte powder, then place a piece of NCAL-Ni anode in the battery mold, sprinkle the electrolyte powder in, flatten it, and then cover it with a layer of BCFZY-NCAL-C or BCFZY-C cathode powder, compact it, and form a ceramic fuel cell.

[0021] The beneficial effects of the above scheme are:

[0022] 1) The low-temperature ceramic fuel cell composite cathode (BCFZY-NCAL) provided by the present invention has higher oxygen ion conductivity and oxygen reduction catalytic activity than the single-phase cathode BCFZY, and can therefore be used as a cathode in low-temperature ceramic fuel cells.

[0023] 2) This invention uses a one-step dry pressing method to prepare ceramic fuel cells, which omits the high-temperature pre-firing step of traditional SOFCs and simplifies the battery manufacturing process.

[0024] 3) The low-temperature ceramic fuel cell provided by this invention can exhibit excellent output power and good repeatability in the low-temperature range;

[0025] 4) The low-temperature ceramic fuel cell composite cathode (BCFZY-NCAL) provided by the present invention can effectively reduce the operating temperature of ceramic fuel cells. Attached Figure Description

[0026] Figure 1 The XRD pattern of the composite cathode BCFZY-NCAL provided in the embodiments of the present invention;

[0027] Figure 2 SEM image of the composite cathode BCFZY-NCAL provided in the embodiments of the present invention;

[0028] Figure 3 XPS image of composite cathode 1BCFZY-2NCAL provided in an embodiment of the present invention;

[0029] Figure 4This is a cross-sectional SEM image of a ceramic fuel cell provided in an embodiment of the present invention;

[0030] Figure 5 IV and IP curves of composite cathode 1BCFZY-2NCAL and single-phase BCFZY cathode ceramic fuel cells provided in the embodiments of the present invention;

[0031] Figure 6 IV and IP curves of the composite cathode 1BCFZY-2NCAL ceramic fuel cell provided in an embodiment of the present invention;

[0032] Figure 7 EIS diagrams and fitting curves of ceramic fuel cells in H2 / air atmosphere at 550°C are provided in embodiments of the present invention.

[0033] Table 1 is a list of fitting parameters (R) for the EIS plot of the ceramic fuel cell provided in the embodiments of the present invention. o R ct R mt R p These are the battery's ohmic resistance, charge transfer resistance, mass transfer resistance, and electrode polarization resistance, respectively. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0037] This invention provides a low-temperature ceramic fuel cell composite cathode, the preparation method of which is as follows:

[0038] 1) Using zirconium nitrate, ferric nitrate, yttrium nitrate, barium nitrate, cobalt nitrate and citric acid as raw materials, weigh the metal ion nitrates and citric acid in a molar ratio of total metal ion:citric acid = 2:3, add deionized water to prepare a 150mL solution, and then heat the solution to 50℃ under stirring for later use.

[0039] 2) Weigh EDTA in an equimolar ratio to the total amount of metal ions, and prepare a 100 mL solution with saturated ammonia water to obtain an EDTA solution; add the EDTA solution to the solution in step 1), and then slowly add saturated ammonia water dropwise until the pH of the solution reaches 8-9. Heat the solution to 110°C with stirring, and stop stirring when the liquid forms a gel to obtain Ba. 0.9 Co 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY) precursor;

[0040] 3) Dry the BCFZY precursor at 130℃ until the liquid is completely evaporated, grind it, then sinter the material in a muffle furnace at 400℃ for 2 hours, grind it, then calcine the material in a muffle furnace at 1100℃ for 8 hours, grind the material to the nanoscale, and obtain BCFZY single-phase cathode powder.

[0041] 4) Commercially purchased Ni 0.8 Co 0.15 Al 0.05 LiO 2-δ (NCAL, purchased from Tianjin Bamo Technology Co., Ltd.) Grind evenly, mix the BCFZY powder prepared in step 3) with commercial NCAL powder, use ethanol as a dispersant, and grind thoroughly in a mortar.

[0042] 5) The above-ground mixture is sintered in air at 600°C for 2 hours, and then further ground and mixed evenly in a mortar to obtain a low-temperature ceramic fuel cell composite cathode.

[0043] Specifically, in this invention, BCFZY powder and commercial NCAL powder are mixed at mass ratios of 1:2, 1:1, and 2:1 to prepare a low-temperature ceramic fuel cell composite cathode (labeled as 1BCFZY-2NCAL, 1BCFZY-1NCAL, and 2BCFZY-1NCAL, respectively).

[0044] like Figure 1 , Figure 2 and Figure 3 As shown, the low-temperature ceramic fuel cell composite cathode provided in this invention contains two oxide phases, whose diffraction peaks are basically consistent with the PDF card (PDF No. 74-1299) of perovskite structure BaZrO3 and the PDF card (PDF No. 87-1562) of layered structure LiNiCo-oxide, respectively, and there are no other impurity phases; its microstructure is that BCFZY nanoparticles are attached to the surface of NCAL microspheres or fill the gaps between NCAL microspheres, and the two form a large number of heterogeneous interfaces.

[0045] like Figure 3 As shown, the 1BCFZY-2NCAL composite cathode provided in this invention has a higher adsorbed oxygen / lattice oxygen ratio (O) than single-phase BCFZY. ads / O lat This indicates that the 1BCFZY-2NCAL composite cathode has more surface oxygen vacancies than the single-phase BCFZY, which means better ion conduction and higher ion conductivity.

[0046] The assembly method of the low-temperature ceramic fuel cell in this invention is as follows:

[0047] 1) Mix NCAL powder and terpineol thoroughly at a mass ratio of 3:1, grind them, then coat the material evenly on nickel foam, dry it, and make NCAL-Ni electrode sheet;

[0048] 2) BCFZY powder was mixed with commercially available ZnO nanopowder (Aladdin, nano zinc oxide, <100nm, purity 99%) at a mass ratio of 2:1, an appropriate amount of alcohol was added and the mixture was ground evenly, and sintered at 700℃ for 2h to obtain 2BCFZY-1ZnO electrolyte powder sample.

[0049] 3) The composite cathode material BCFZY-NCAL was mixed with carbon powder (Aladdin, activated carbon powder, purity 99.5%) at a mass ratio of 9:1 to obtain BCFZY-NCAL-C cathode powder;

[0050] 4) Weigh 0.3g of 2BCFZY-1ZnO electrolyte powder, place an NCAL-Ni electrode in the battery mold, sprinkle the electrolyte powder in, flatten it, and then cover it with a layer of BCFZY-NCAL-C cathode powder. Use a dry powder press to compact the material at 10MPa to form a ceramic fuel cell.

[0051] like Figure 4 As shown, the ceramic fuel cell assembled with the 1BCFZY-2NCAL composite cathode provided in this invention has a three-layer structure of "anode / electrolyte / cathode". The electrolyte and cathode have good contact, the electrolyte layer has good airtightness, and the cathode layer has a porous structure.

[0052] like Figure 5 As shown, the three types of BCFZY-NCAL composite cathode ceramic fuel cells provided in this invention all exhibit higher power densities at 550°C than those of single-phase BCFZY cathode ceramic fuel cells, demonstrating that introducing NCAL into the BCFZY cathode can improve its cathode catalytic activity and battery performance. Among them, the 1BCFZY-2NCAL composite cathode ceramic fuel cell exhibits the best performance, achieving a power density of 668.59 mW / cm² at 550°C. -2 .

[0053] like Figure 6 As shown, the 1BCFZY-2NCAL composite cathode ceramic fuel cell provided in this invention exhibits an open-circuit voltage above 1.06V in the low-temperature range of 450-550℃, without any short-circuit phenomenon. Even at a low temperature of 450℃, it still demonstrates considerable output performance, achieving a power output of 276.72mW / cm². -2 This demonstrates the excellent low-temperature oxygen reduction catalytic activity of the composite cathode.

[0054] like Figure 7 As shown, the charge transfer resistance and electrode polarization resistance of the three BCFZY-NCAL composite cathode ceramic fuel cells provided in this invention are lower than those of the single-phase BCFZY cathode ceramic fuel cells, indicating that the composite method increases the ionic conductivity of the cathode, thereby effectively promoting charge transfer. The impedance spectrum fitting results of the three BCFZY-NCAL composite cathode ceramic fuel cells and the BCFZY single-phase cathode ceramic fuel cell are as follows.

[0055]

[0056] As shown above, the low-temperature ceramic fuel cell composite cathode provided by the present invention can effectively reduce the operating temperature of ceramic fuel cells / solid oxide fuel cells.

[0057] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a composite cathode for a low temperature ceramic fuel cell, characterized in that, Comprising the following steps: 1) Weigh the metal ion nitrate and citric acid according to the total amount of metal ions: citric acid = 2:3 in molar ratio, add ionized water to prepare a 150 mL solution, then heat the solution to 50℃ under stirring, ready for use; 2) Weigh EDTA according to the molar ratio of the total amount of metal ions, then use saturated ammonia water to prepare a 100 mL solution to obtain an EDTA solution; add the EDTA solution to the solution in step 1), then slowly add saturated ammonia water until the pH value of the solution reaches 8-9, heat the solution to 110℃ under stirring, stop stirring when the liquid forms a gel, and obtain the BCFZY precursor; 3) Dry the BCFZY precursor at 130℃ until the liquid is completely volatilized, grind, then sinter the material in a muffle furnace at 400℃ for 2 hours, grind again, then calcine the material in a muffle furnace at 1100℃ for 8 hours, grind the material to nanoscale, and obtain the BCFZY single-phase cathode powder; 4) Grind the NCAL uniformly, mix the BCFZY powder prepared in step 3) and the NCAL powder, and use ethanol as a dispersant to grind thoroughly in a mortar; 5) Sinter the mixture after grinding in step 4) in air at 600℃ for 2h, further grind in a mortar, and obtain the low-temperature ceramic fuel cell composite cathode.

2. The production method according to claim 1, characterized by, The metal ion nitrate in step 1) is one or more of barium nitrate, cobalt nitrate, iron nitrate, zirconium nitrate, or yttrium nitrate.

3. A low temperature ceramic fuel cell composite cathode, characterized by, Prepared according to the preparation method of claim 1 or 2.

4. A fuel cell characterized by comprising: The low-temperature ceramic fuel cell composite cathode of claim 3.

5. The method of assembling a fuel cell stack of claim 4, wherein Comprising the following steps: 1) Mix and grind the NCAL powder and terpineol according to a mass ratio of 3:1, then evenly coat the material on the nickel foam, dry, and prepare the NCAL-Ni anode sheet; 2) Mix the BCFZY powder and ZnO nanopowder according to a mass ratio of 2:1, add an appropriate amount of alcohol to grind uniformly, and sinter at 700℃ for 2h to obtain the BCFZY-ZnO electrolyte powder sample; 3) Mix the composite cathode material BCFZY-NCAL with carbon powder according to a mass ratio of 9:1 to obtain the BCFZY-NCAL-C cathode powder; 4) Weigh 0.3g of BCFZY-ZnO electrolyte powder, then put a piece of NCAL-Ni anode in the cell mold, sprinkle the electrolyte powder, flatten, cover with a layer of BCFZY-NCAL-C cathode powder, and compact to form a ceramic fuel cell.

6. The fuel cell obtained by the assembly method of claim 5.

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