管式电解质支撑型直接碳固体氧化物燃料电池的浸渍法制备及电性能

Fabrication and Performance of Tubular Electrolyte-Supporting Direct Carbon Solid Oxide Fuel Cell by Dip Coating Technique

管状电解质支撑型固体氧化物燃料电池(SOFC)具有稳定性高、电极选择范围广、易封接等优点,很适合应用于直接碳固体氧化物燃料电池(DC-SOFC)现阶段的基础研究中。为实现管状电解质支撑型SOFC的便捷制备,本研究开发了管状YSZ(钇稳定化氧化锆)电解质支撑膜的浸渍法制备工艺。组装了电极材料为Ag-GDC(钆掺杂氧化铈)的电解质支撑型SOFC单电池。测试了单电池分别以加湿氢气和担载5%(w,质量分数)Fe的活性炭为燃料,环境空气为氧化剂的电性能。电池的开路电压接近理论值,且扫描电镜分析结果表明电解质膜致密。单电池以活性碳为燃料在800°C取得了280 m W?cm^(-2)的最大功率密度,接近其以加湿氢气为燃料的330 m W?cm^(-2)。交流阻抗谱结果表明YSZ电解质的欧姆电阻是影响电池性能的主要原因。DC-SOFC以恒电流1 A放电,运行了2.1 h,燃料利用率为36%。DC-SOFC二次装载碳燃料后的电性能几乎与初次的性能一样,表明制备的YSZ电解质支撑膜可稳定的应用于DC-SOFCs中。分析了DC-SOFC放电过程中电性能衰减的机制。

Tubular electrolyte-supporting solid oxide fuel cells （SOFCs） are particularly suitable for fundamental research of direct carbon SOFCs （DC-SOFCs） because they exhibit high stability, have simple seal requirements and are compatible with a variety of electrode materials. We have developed a dip-coating technique for the simple preparation of tubular electrolyte-supporting SOFCs using tubular yttria-stabilized zirconia （YSZ） electrolyte membrane substrates. Single SOFCs were assembled with a cermet consisting of gadolinium doped ceria （GDC） mixed with silver as both the cathode and anode. The single cells were tested with humidified hydrogen and 5% Fe-loaded activated carbon （w, mass fraction） as the fuel. Ambient air was used as the oxidant. The open-circuit voltages were comparable to the theoretical values and the scanning electron microscopy （SEM） results showed that the electrolyte membrane was quite dense. The cell that used activated carbon as fuel exhibited a maximum power density of 280 mW·cm^-2 at 800℃, which was close to that of a cell that used hydrogen as fuel （330 mW·cm^-2）. The results of impedance spectroscopy showed that the performance of the cells was mainly influenced by the electrolyte ohmic resistance. The discharge time of the DC-SOFC at a constant current of 1 Awas 2.1 h, which represented a fuel utilization of 36%. The performance of the DC-SOFC with reloaded fuel was nearly identical to its initial performance, which indicated that the YSZ electrolyte membrane substrate was stable when used in the DC-SOFCs. The degradation performance of the DC-SOFC during the discharge test was also analyzed.