Low-temperature ceramic fuel cell

Abstract

The invention discloses a low-temperature ceramic fuel cell, which is characterized in that an electrolyte material of the cell is Cu and Sm co-doped CeO2, and the chemical formula of the electrolyte material is Cu < 0.15 > Sm < 0.05 > Ce < 0.8 > O < 2-delta >, the electrode material of the battery is characterized in that NCAL is coated with an LSCF coating; and the electrode is of a symmetrical structure. The ceramic fuel cell constructed based on the electrolyte and the electrode material can realize good electrochemical performance and stable power output at low temperature, the maximum output power density reaches 800mW / cm < 2 > and the ionic conductivity is greater than 0.1 S / cm at the operating temperature of 500 DEG C, and the continuous and stable operation time exceeds 250 hours.

Description

Technical Field

[0001] The present invention relates to a solid oxide fuel cell, in particular to a low-temperature ceramic fuel cell. Background Art

[0002] Low-temperature solid oxide fuel cells (SOFCs, 350-550°C) are designed to overcome the high operating costs of conventional yttria-stabilized zirconia (YSZ)-based SOFCs, which must operate above 800°C. Existing low-temperature solid oxide fuel cell electrolytes, such as Sm-doped CeO2 (SDC) and Gd-doped CeO2 (GDC), often suffer from conductivity limitations and chemical instability at low temperatures. Furthermore, the conventional electrode-electrolyte interface is susceptible to degradation and exfoliation during prolonged operation. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a low-temperature ceramic fuel cell, the electrolyte material of which has an ionic conductivity of up to 0.1S / cm at low temperatures (300-500°C), and its electrode material and electrolyte material have good chemical compatibility and electrochemical stability, which can effectively overcome the problem of easy degradation and peeling of the existing electrode-electrolyte interface during long-term operation.

[0004] Technical solution: The low-temperature ceramic fuel cell of the present invention has an electrolyte material of Cu and Sm co-doped CeO2, whose chemical formula is Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ The electrode material of the battery is NCAL (Ni 0.8 Co 0.15 Al 0.05 LiO2) is coated with LSCF coating (LaSrCoFeO3).

[0005] The structure of the battery is NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF.

[0006] The Cu and Sm co-doped CeO2 electrolyte material is prepared by the following method, comprising the following steps:

[0007] (1) adding copper nitrate and samarium nitrate to cerium nitrate solution and continuously stirring at high temperature to ensure that the materials are completely dissolved;

[0008] (2) adding sodium carbonate solution dropwise to the solution of step (1) to promote coprecipitation, and adjusting the pH value of the solution to 7-8 after the addition; if the pH value is too high, the subsequent co-doping will cause the disappearance of a certain element;

[0009] (3) Filter out the coprecipitate after the reaction in step (2), wash and dry it, and then sinter it at 750-800°C for 3-4h to obtain Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ Electrolyte powder material.

[0010] This sintering temperature is the main parameter of the Cu-Sm co-doped CeO2 lattice. If it is lower than this sintering temperature, doped CeO2 cannot be formed and its structure is fluorite structure; if it is higher than this sintering temperature, Sm2O3 may appear instead of CeO2 with Sm entering the fluorite structure.

[0011] Wherein, in step (1), the molar ratio of copper nitrate, samarium nitrate and cerium nitrate added is calculated based on the stoichiometric ratio of copper, samarium and cerium, that is, the molar ratio of copper nitrate, samarium nitrate and cerium nitrate added is 0.15:0.05:0.8.

[0012] Wherein, in step (1), stirring is continued at a speed of 700-750 rpm for 2-3 hours at a temperature not lower than 80° C. to ensure complete dissolution.

[0013] Wherein, in step (2), the concentration of the sodium carbonate solution is not higher than 1M, and the amount of sodium carbonate added is until no obvious precipitate is produced in the solution.

[0014] Wherein, in step (3), the drying temperature is 120-125° C., and the drying time is 10-12 hours.

[0015] The electrode material is prepared by the following method, comprising the following steps:

[0016] (1) Preparation of NCAL electrodes;

[0017] (2) Mix LSCF powder and pine oil to make a slurry, and evenly coat the slurry on the NCAL electrode;

[0018] (3) The coated electrode is dried and sintered to obtain a NCAL electrode coated with LSCF.

[0019] In step (1), the NCAL electrode is prepared by the following method: specifically, 8-10 g NCAL is mixed with 5-6 mL terpineol to prepare a slurry, the slurry is coated on nickel foam, and then dried at 90-95° C. for 1-1.5 hours to obtain the NCAL electrode.

[0020] Wherein, in step (2), 9-10 g of LSCF powder and 5-6 mL of terpineol are mixed to prepare a slurry.

[0021] Wherein, in step (3), the drying temperature is 90-95° C., and the drying time is 1-1.5 h; the sintering temperature is not higher than 600° C., and the sintering time is 0.5-1 h.

[0022] The electrolyte material used in the ceramic fuel cell of the present invention is Cu-Sm co-doped CeO2, whose chemical formula is Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ NCAL (Ni 0.8 Co 0.15 Al 0.05 The surface of the NCAL material coated with LSCF (LaSrCoFeO3) was used as the symmetrical electrode of the fuel cell; the NCAL electrode coated with LSCF, the electrolyte powder co-doped with CeO2 by Cu-Sm and the NCAL electrode coated with LSCF were sequentially filled into a steel mold and pressed under a pressure of 6-12MP to obtain NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF structure low-temperature ceramic fuel cell.

[0023] The NCAL@LSCF / Cu prepared by the dry pressing method of the present invention 0.15 Sm 0.05 Ce 0.8 O 2-δ The NCAL@LSCF battery achieved an ionic conductivity exceeding 0.1 S / cm and a power of 800 mW / cm at an operating temperature of 500°C. 2 The battery can continue to work for more than 250 hours at this temperature.

[0024] The electrolyte material of the low-temperature ceramic fuel cell of the present invention adopts CeO2 co-doped with copper and samarium. 3+ and Cu 2+ The co-doping of Sm 3+ stabilizes the formation of oxygen vacancies, while Cu 2+ The large amount of oxygen vacancies in the electrolyte and the highly redox active Cu 2+ and Cu + sites, which can greatly enhance the ionic conductivity of electrolyte materials.

[0025] The LSCF coating layer is located between the electrolyte material and the NCAL electrode. On the one hand, LSCF can enhance the ORR kinetics of the oxygen reduction reaction and reduce the polarization resistance. On the other hand, it can promote the stability of the interface between the electrolyte and the electrode, preventing the degradation and peeling of the electrolyte and electrode materials during long-term operation. That is, the NCAL electrode with LSCF coating can effectively prevent interface degradation and stratification, ensuring durability.

[0026] Beneficial effects: Compared with the existing technology, the present invention has the following significant effects: the electrolyte material of the battery of the present invention is Cu-Sm co-doped CeO2, and the defect-assisted mechanism of oxygen vacancies and electron-ion coupling is designed to ensure its efficient ion transport performance; the NCAL electrode with LSCF coating on the surface can improve its catalytic active interface and has good robustness, which can significantly reduce the polarization resistance while promoting the electrode redox reaction; the low-temperature ceramic fuel cell of the present invention has a maximum output power density of 800mW / cm under the operating temperature of 500℃ 2 , ion conductivity is greater than 0.1S / cm, and the continuous stable operation time exceeds 250 hours; the ceramic fuel cell constructed based on the electrolyte and electrode materials of the present invention can achieve good electrochemical performance and stable power output at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a performance curve of the low-temperature ceramic fuel cell prepared in Example 1; wherein, Figure 1 (a) NCAL@LSCF / Cu of Example 1 0.15 Sm 0.05 Ce 0.8 O 2-δ / Performance curve of NCAL@LSCF structure battery at operating temperature of 440℃~500℃; Figure 1 (b) The battery with the same electrolyte but without LSCF coating on the NCAL electrode, i.e. NCAL / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / Performance curve of NCAL structure battery under operating temperature conditions of 440℃~500℃;

[0028] Figure 2 The electrochemical impedance spectrum of the low-temperature ceramic fuel cell prepared in Example 1 is shown in FIG. Figure 2 (a) NCAL@LSCF / Cu of Example 1 0.15 Sm 0.05 Ce 0.8 O 2-δ / Electrochemical impedance spectroscopy of NCAL@LSCF structured battery at an operating temperature of 440℃~500℃; Figure 2 (b) The battery structure with the same electrolyte but without LSCF coating on the NCAL electrode, i.e. NCAL / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / Electrochemical impedance spectroscopy of NCAL structure battery at operating temperature of 440℃~500℃;

[0029] Figure 3 This is a graph showing the electrochemical performance of the low-temperature ceramic fuel cell prepared in Example 1 after continuous operation for 250 hours at an operating voltage above 0.60 V;

[0030] Figure 4 The low-temperature ceramic fuel cell NCAL@LSCF / Cu prepared in Example 1 at 500℃, 470℃ and 440℃ respectively 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF and NCAL / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ DRT analysis of the electrochemical impedance spectroscopy of NCAL. DETAILED DESCRIPTION

[0031] Example 1

[0032] The electrolyte material of the low-temperature ceramic fuel cell of the present invention is CeO2 co-doped with Cu and Sm, and its chemical formula is Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ ; The battery electrode material is NCAL (Ni 0.8 Co 0.15 Al 0.05 LiO2) is coated with LSCF coating (LaSrCoFeO3).

[0033] Among them, the electrolyte material is Cu-Sm co-doped CeO2, whose chemical formula is Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ , prepared by the following method, specifically:

[0034] The raw materials used are: cerium (III) nitrate nonahydrate (ACS, 99%), samarium (III) nitrate hexahydrate, copper nitrate hexahydrate (ACS, 99%); the precipitant used is: sodium carbonate monohydrate (ACS, 99%); Cu was prepared by coprecipitation method. 0.15 Sm 0.05 Ce 0.8 O 2-δ The molar ratio of the solid solution, cerium (III) nitrate nonahydrate, samarium (III) nitrate hexahydrate, and copper nitrate hexahydrate is determined according to the stoichiometric ratio of each element in the chemical formula;

[0035] The specific preparation steps are as follows:

[0036] (1) Dissolve 0.008 mol of cerium nitrate in 300 mL of deionized water and stir at 40 rpm at 60°C to obtain a cerium nitrate solution; dissolve 0.0015 mol of copper nitrate and 0.0005 mol of samarium nitrate in 100 mL of deionized water and stir until completely dissolved;

[0037] (2) adding the copper nitrate solution and the samarium nitrate solution to the cerium nitrate solution, mixing, and continuously stirring at 80° C. and 700 rpm for 3 hours to ensure complete dissolution, to obtain a mixed solution;

[0038] (3) A 1 M sodium carbonate (Na2CO3) solution was prepared in 150 mL of deionized water and added dropwise to the mixed solution to promote coprecipitation. When no obvious precipitate was produced in the solution, the addition was stopped. The pH of the solution was measured at this time, and then the pH of the solution was adjusted to 7-8 with ammonia water to promote precipitation again.

[0039] (4) The coprecipitate obtained in step (3) was filtered, washed with ethanol and deionized water several times to remove impurities, and then dried at 120°C for 12 hours; the dried material was ground into fine powder and sintered at 750°C for 4 hours at a heating rate of 4°C / min to obtain Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ Electrolyte powder material.

[0040] The electrode material is an NCAL electrode material coated with an LSCF coating on the surface, which is prepared by the following method:

[0041] NCAL was used as the symmetrical electrode and was purchased from Tianjin Bamo Company;

[0042] (1) NCAL was first mixed with an appropriate amount of terpineol to prepare a slurry (5 mL of terpineol to 10 g of NCAL powder), which was then coated on nickel foam and finally dried at 90 °C for 1 h to prepare an NCAL electrode.

[0043] (2) 10 g of LSCF powder was mixed with 5 mL of pine oil to prepare a slurry; the slurry was then coated on the NCAL electrode using a brush coating technique, ensuring a uniform coating; the coated electrode was then dried at 95 °C for 1 hour and sintered at 600 °C for 1 hour to form a strong LSCF functional coating on the NCAL electrode, thereby improving the electrochemical performance and stability of the electrode in solid oxide fuel cell applications.

[0044] The prepared NCAL electrode with LSCF coating on the surface, Cu-Sm co-doped CeO2 electrolyte powder and NCAL electrode with LSCF coating on the surface were sequentially filled into a steel mold and pressed under a pressure of 6-12 MP to obtain NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF structure low-temperature ceramic fuel cell.

[0045] pass Figure 1 It can be seen that the output power of the battery coated with the LSCF coating in Example 1 at an operating temperature of 440° C. to 500° C. is better than the output performance of the battery not coated with the LSCF coating.

[0046] pass Figure 2 It can be seen that in Example 1NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ The polarization resistance of the NCAL@LSCF structured battery is only 0.1Ωcm 2 The impedance of the battery without LSCF coating is about 0.2Ωcm 2 The impedance value differs by a factor of 2. The greater the impedance, the more difficult the electrode reaction is, and the corresponding battery performance is lower.

[0047] pass Figure 3It can be seen that the low-temperature ceramic fuel cell prepared in Example 1 can operate stably and continuously for 250 hours at an operating voltage of more than 0.60V with almost no attenuation. This great stability of operation is due to the active coating of LSCF on the NCAL electrode. The active coating of LSCF creates a potential barrier to prevent the generation of electrons due to the formation of the junction. The fluctuations in the open circuit voltage OCV during operation are due to the condensation of the generated water vapor on the inner wall of the long tube gas inlet and outlet of the test equipment, thereby generating a backup pressure to divide the pressure and thus reduce the voltage. The introduction of LSCF coating on the NCAL electrode, together with CSCO (Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ ) electrolyte to form a battery. This structure optimizes charge transfer at the electrode-electrolyte interface and promotes efficient electrochemical reactions. The introduction of the LSCF coating on the NCAL electrode also leads to the formation of a built-in electric field, which minimizes the diffusion of lithium ions in the NCAL and hinders the decomposition of the electrode material, thereby improving the overall durability of the battery.

[0048] Figure 4 The DRT method can effectively separate the coupled charge transfer and mass transfer processes in fuel cells. The DRT peak corresponds to a specific physical process, such as the P1 peak represents the mass transfer process, and the P4 peak corresponds to the cathode HER process. It can be found that as the temperature decreases, the P4 peak area decreases, and the corresponding cathode HER process slows down. Figure 4 (ac) shows that NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF combination exhibits significantly lower polarization resistance, further deconvolution NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ / NCAL@LSCF battery D peak to obtain the peak area, such as Figure 4 As shown in e.

[0049] Figure 4 e, for NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δFor the NCAL@LSCF, the area of peak P1 is consistently lower at 500°C (0.00625), 470°C (0.00704), and 440°C (0.00876), indicating more efficient proton transport, which is advantageous for fuel cell applications. In contrast, the cell without LSCF coating shows higher area values, indicating a decrease in proton transport efficiency under the applied in situ conditions. Figure 4 d is the ionic conductivity of the electrolyte under different temperature conditions, which is given by Figure 4 d shows that the ionic conductivity of the electrolyte material of the present invention is high; Figure 4 The slope of the curve in d can be obtained, and the NCAL@LSCF / Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ The activation energy of the / NCAL@LSCF structured battery is much lower than that of the uncoated LSCF battery.

[0050] The present invention combines a highly conductive Cu-Sm co-doped CeO2 electrolyte with LSCF-coated NCAL electrodes, providing enhanced redox reaction (ORR) kinetics, mechanical durability, and electrochemical stability for extended operation.

Claims

1. A low-temperature ceramic fuel cell, characterized in that: The electrolyte material of the battery is CeO2 co-doped with Cu and Sm, and its chemical formula is Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ ; The electrode material of the battery is NCAL coated with LSCF coating; and the electrode has a symmetrical structure.

2. The low-temperature ceramic fuel cell according to claim 1, characterized in that The Cu and Sm co-doped CeO2 electrolyte material is prepared by the following method, comprising the following steps: (1) adding copper nitrate and samarium nitrate to cerium nitrate solution and continuously stirring at high temperature to ensure that the materials are completely dissolved; (2) adding sodium carbonate solution dropwise to the solution of step (1), and adjusting the pH value of the solution to 7-8 after the addition; (3) Filter out the coprecipitate after the reaction in step (2), wash and dry it, and then sinter it at 750-800°C for 3-4h to obtain Cu 0.15 Sm 0.05 Ce 0.8 O 2-δ Electrolyte materials.

3. The low-temperature ceramic fuel cell according to claim 2, characterized in that: In step (1), based on the stoichiometric ratio of copper, samarium and cerium, the molar ratio of copper nitrate, samarium nitrate and cerium nitrate added is 0.15:0.05:0.

8.

4. The low-temperature ceramic fuel cell according to claim 2, characterized in that: In step (1), stirring is continued at a temperature of not less than 80° C. and a rotation speed of 700 to 750 rpm for 2 to 3 hours.

5. The low-temperature ceramic fuel cell according to claim 2, characterized in that: In step (2), the concentration of the sodium carbonate solution is not higher than 1M, and the amount of sodium carbonate added is until no obvious precipitate is produced in the solution.

6. The low-temperature ceramic fuel cell according to claim 2, characterized in that: In step (3), the drying temperature is 120-125° C., and the drying time is 10-12 hours.

7. The low-temperature ceramic fuel cell according to claim 1, characterized in that The electrode material is prepared by the following method, comprising the following steps: (1) Preparation of NCAL electrodes; (2) Mix LSCF powder and pine oil to make a slurry, and evenly coat the slurry on the NCAL electrode; (3) The coated electrode is dried and sintered to obtain a NCAL electrode coated with LSCF.

8. The low-temperature ceramic fuel cell according to claim 7, characterized in that: In step (1), the NCAL electrode is prepared by the following method: specifically, 8-10 g NCAL is mixed with 5-6 mL terpineol to prepare a slurry, the slurry is coated on nickel foam, and then dried at 90-95° C. for 1-1.5 hours to obtain the NCAL electrode.

9. The low-temperature ceramic fuel cell according to claim 7, characterized in that: In step (2), 9-10 g of LSCF powder and 5-6 mL of terpineol were mixed to prepare a slurry.

10. The low-temperature ceramic fuel cell according to claim 7, characterized in that: In step (3), the drying temperature is 90-95° C., and the drying time is 1-1.5 h; the sintering temperature is not higher than 600° C., and the sintering time is 0.5-1 h.

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