固体氧化物燃料电池作为新型的能源转换装置,具有高效、清洁、稳定性高、灵活多样等特点,有着良好的发展前景。它的中低温化对于商业应用具有十分重要的意义,现阶段的研究重点主要集中于将操作温度从传统的800—1 000℃降低到600℃甚至以下。本文集中介绍了应用于600℃以下的中低温固体氧化物燃料电池,分别从低温电解质、阴极和阳极等方面进行了比较和讨论。电解质方面可以采用在低温下具有较高氧离子电导率的氧化铈基电解质,降低电解质的有效厚度,加入电子阻隔层的双层电解质结构来阻挡电子传导从而提高开路电压的方法来实现其中低温化。电极方面不仅可以通过新材料的开发来提高在低温下的催化活性,同时还可以利用离子浸渍法对电极微结构进行优化,增加三相界面长度和反应活性位,在实现电极电阻减小的同时改善阳极的燃料适应性,从而可使用更多种类的碳氢化合物作为燃料而不产生积炭现象。此外,文章还对近年来兴起的用于低温的单室固体氧化物燃料电池和微型固体氧化物燃料电池进行了介绍,这一系列新型固体氧化物燃料电池在其中低温化进程中也具有重要的影响。
Solid oxide fuel cells (SOFCs) are an novel energy conversion device, which has been extensively used for its high energy efficiency, high stability, fuel flexibility, and low pollution emission. Lowering down its operating temperature is important for commercialization. More attentions are therefore paid on how to decrease the operating temperature from traditional 800--1 000~C to 600~C or below. The paper summarizes the development of the electrolytes, cathodes, and anodes for SOFCs operated below 600~C. Choosing alternative ceria-based oxides with high ionic conductivity at low temperature, decreasing the electrolyte thickness, and constructing bilayered electrolytes with additional electronic blocking layer to enhance the open circuit voltage are all effective approaches for the improving electrolytes. While for the electrodes, novel materials are developed to increase the catalytic activity at low temperature. Moreover, ion-impregnation method is applied to optimize the microstrncture of electrodes. Thus the triple phase boundary and active site has been enhanced, resulting in decreased electrode resistance and direct utilization of hydrocarbon without carbon deposition. In addition, new types of low temperature SOFCs such as single chamber SOFCs and micro SOFCs are also presented, which might have significant impact on the development of low temperature SOFCs.