银基陶瓷复合电极的电性能及其在固体氧化物燃料电池中的应用研究
发布时间：2018-12-08 16:30
【摘要】：固体氧化物燃料电池(SOFCs)是一种能够直接将燃料中的化学能转化为电能的发电装置,具有电转换效率高、对环境友好、燃料适应性广及寿命长等优点,被公认为是具有良好发展前景的新型发电技术。SOFC的电极材料对SOFC的性能具有重要的影响。传统的SOFC采用镍基阳极和掺杂锰酸镧复合阴极,但镍基阳极在使用含碳燃料时会因为促进积炭而降低电池性能,锰酸镧阴极的氧还原能力也不够强,特别是在温度降低时,阴极极化电阻将显著增大,从而严重影响电池的输出性能。针对传统电极存在的问题,本论文研究了银基陶瓷复合材料作为SOFC的阴极和阳极的性能。首先采用传统YSZ电解质,分别采用不同Ag比例的Ag-YSZ和Ag-GDC为电极材料,制备对称电极,在空气中对其进行了交流阻抗谱测试,分别选出Ag-YSZ和Ag-GDC电极的最佳成分比;结合相应电极材料组装成的SOFC电化学性能测试结果,区分出阴极和阳极的极化电阻,并对实验结果进行了讨论和分析。结果表明,在相同的Ag含量(质量比)时,Ag-YSZ在空气下的极化阻抗普遍小于Ag-GDC,且当Ag的含量为65%时,Ag-YSZ(65Ag-YSZ)在空气中的极化阻抗最低,而Ag-GDC在空气中的最低极化阻抗时的Ag含量是70%(70Ag-GDC)。分别采用65Ag-YSZ(Ag的质量百分数为65%)和70Ag-GDC(Ag的质量百分数为70%)为电极制备SOFC单电池并使用加湿氢气(3 vol.%H2O)为燃料进行测试。800?C时,采用65Ag-YSZ和70Ag-GDC既作为阴极又作为阳极的电池,前者的开路电压和最大功率密度分别为1.08 V和200mW·cm-2,后者的分别为1.09 V和214 mW·cm-2。采用阻抗谱测试和分析结果表明,虽然在空气气氛中Ag-YSZ的极化电阻比Ag-GDC低,但在加湿氢气中,Ag-GDC的极化电阻比Ag-YSZ低,说明Ag-YSZ更适合用作阴极,而Ag-GDC更适合用作阳极。在上述研究基础上,研究了银基陶瓷复合电极用于直接碳固体氧化物燃料电池(DC-SOFC)的性能。用65Ag-GDC作为DC-SOFC的阳极,65Ag-YSZ作为其阴极,830?C测试温度下,其最大输出功率密度能达到~339 m W·cm-2,比传统NiO-YSZ阳极的性能要优越许多。结果表明,采用Ag-GDC复合电极材料能够有效地提高电池的输出性能。
[Abstract]:Solid oxide fuel cell (SOFCs) is a kind of power generation device which can directly convert the chemical energy of fuel into electric energy. It has the advantages of high efficiency of electric conversion, friendly environment, wide fuel adaptability and long life. The electrode material of SOFC has an important influence on the performance of SOFC. The traditional SOFC uses nickel based anode and doped lanthanum manganate composite cathode, but the nickel base anode can reduce the battery performance because of promoting carbon deposition, and the oxygen reduction ability of lanthanum manganate cathode is not strong enough, especially when the temperature is lowered. The cathode polarization resistance will increase significantly, which will seriously affect the output performance of the battery. Aiming at the problems of traditional electrodes, the properties of silver based ceramic composites as cathodes and anodes of SOFC were studied in this paper. Firstly, symmetrical electrodes were prepared by using traditional YSZ electrolytes and Ag-YSZ and Ag-GDC with different Ag ratios, respectively, and were measured by AC impedance spectroscopy in air. The optimum composition ratio of Ag-YSZ and Ag-GDC electrode was selected. The polarization resistance of cathode and anode is distinguished by combining the electrochemical performance test results of SOFC assembled with corresponding electrode materials and the experimental results are discussed and analyzed. The results show that at the same Ag content (mass ratio), the polarization impedance of Ag-YSZ in air is generally lower than that of Ag-GDC, and when the content of Ag is 65, the polarization impedance of Ag-YSZ (65Ag-YSZ) in air is the lowest. The Ag content of Ag-GDC in air at the lowest polarization impedance is 70% (70Ag-GDC). Using 65Ag-YSZ (65% of Ag) and 70Ag-GDC (70% of Ag) as electrodes to prepare SOFC single cell and test with 3 vol.%H2O as fuel. Using 65Ag-YSZ and 70Ag-GDC as both cathode and anode, the open circuit voltage and maximum power density of the former are 1.08 V and 200mW cm-2, respectively, the latter are 1.09 V and 214 mW cm-2., respectively. The results of impedance spectroscopy show that the polarization resistance of Ag-YSZ is lower than that of Ag-GDC in air atmosphere, but the polarization resistance of Ag-GDC is lower than that of Ag-YSZ in humidified hydrogen, which indicates that Ag-YSZ is more suitable as cathode. Ag-GDC is more suitable as anode. Based on the above research, the performance of silver based ceramic composite electrode for direct carbon solid oxide fuel cell (DC-SOFC) was studied. Using 65Ag-GDC as the anode of DC-SOFC and 65Ag-YSZ as its cathode, the maximum output power density of 830 鈩，
本文编号：2368647
[Abstract]:Solid oxide fuel cell (SOFCs) is a kind of power generation device which can directly convert the chemical energy of fuel into electric energy. It has the advantages of high efficiency of electric conversion, friendly environment, wide fuel adaptability and long life. The electrode material of SOFC has an important influence on the performance of SOFC. The traditional SOFC uses nickel based anode and doped lanthanum manganate composite cathode, but the nickel base anode can reduce the battery performance because of promoting carbon deposition, and the oxygen reduction ability of lanthanum manganate cathode is not strong enough, especially when the temperature is lowered. The cathode polarization resistance will increase significantly, which will seriously affect the output performance of the battery. Aiming at the problems of traditional electrodes, the properties of silver based ceramic composites as cathodes and anodes of SOFC were studied in this paper. Firstly, symmetrical electrodes were prepared by using traditional YSZ electrolytes and Ag-YSZ and Ag-GDC with different Ag ratios, respectively, and were measured by AC impedance spectroscopy in air. The optimum composition ratio of Ag-YSZ and Ag-GDC electrode was selected. The polarization resistance of cathode and anode is distinguished by combining the electrochemical performance test results of SOFC assembled with corresponding electrode materials and the experimental results are discussed and analyzed. The results show that at the same Ag content (mass ratio), the polarization impedance of Ag-YSZ in air is generally lower than that of Ag-GDC, and when the content of Ag is 65, the polarization impedance of Ag-YSZ (65Ag-YSZ) in air is the lowest. The Ag content of Ag-GDC in air at the lowest polarization impedance is 70% (70Ag-GDC). Using 65Ag-YSZ (65% of Ag) and 70Ag-GDC (70% of Ag) as electrodes to prepare SOFC single cell and test with 3 vol.%H2O as fuel. Using 65Ag-YSZ and 70Ag-GDC as both cathode and anode, the open circuit voltage and maximum power density of the former are 1.08 V and 200mW cm-2, respectively, the latter are 1.09 V and 214 mW cm-2., respectively. The results of impedance spectroscopy show that the polarization resistance of Ag-YSZ is lower than that of Ag-GDC in air atmosphere, but the polarization resistance of Ag-GDC is lower than that of Ag-YSZ in humidified hydrogen, which indicates that Ag-YSZ is more suitable as cathode. Ag-GDC is more suitable as anode. Based on the above research, the performance of silver based ceramic composite electrode for direct carbon solid oxide fuel cell (DC-SOFC) was studied. Using 65Ag-GDC as the anode of DC-SOFC and 65Ag-YSZ as its cathode, the maximum output power density of 830 鈩，
本文编号：2368647
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