单气室固体氧化物燃料电池的材料、微堆结构与相关应用

单气室固体氧化物燃料电池(SC-SOFC)是一种整个电池处在单一气室中,阳极和阴极分别对混合气体中的燃料和氧气进行选择催化产生电动势的特殊结构燃料电池.SC-SOFC因其独特的原理和结构而具有无需密封、易于堆叠、可以快速启动和不易发生积碳等诸多优点,有很大的应用潜力.作者在SC-SOFC的原理和特点的基础上,系统地总结了SC-SOFC所用材料、微堆结构设计、衰退机制及应用方面的研究进展;以提高SC-SOFC微堆的输出电压和功率为目的,改进预混气体环境下运行的微堆结构,采取星型布局的四电池微堆其输出功率提高到420 m W;随后,逐步改进供气方式,结合计算流体力学数值模拟研究,提出了单路多点供气和双路多点供气模式,成功地将单个SC-SOFC微堆模块的输出功率提升到8.178 W,进而开展了微堆模块外部串并联和与燃烧器的结合实验验证.研究结果表明,SC-SOFC可以很便捷地连接成微堆模块并产生数瓦的输出功率,未来有望用于以供热为主型的热电联供系统.作者还借助原位电阻和开路电压的原位同步测试,阐明了Ni在CH4-O2气氛中的反复氧化-还原循环是SC-SOFC发生不可逆衰退的主要机制,这一发现后来催生出氧化-还原法制备多孔金属的新技术.

Materials,Micro-Stacks and Related Applications of Single-Chamber Solid Oxide Fuel Cells

Single-chamber solid oxide fuel cell (SC-SOFC) is a special type of fuel cells, in which both an anode and a cathode are placed in one chamber. Its working principle relies on the selective catalytic activity of the electrodes towards fuel and oxidant in a gas mixture, leading to the generation of an electromotive force. Because of its unique principle and structure, SC-SOFC has many advantages such as sealing-free, easy stacking, quick start-up and no carbon deposition, thus, it possesses large potential in application. Herein, the principles and characteristics of SC-SOFC are introduced. Furthermore, the SC-SOFC materials, micro-stack design, degeneration mechanisms and potential applications in recent years are reviewed systematically. In order to improve the output voltage and power of SC-SOFC micro-stack, the structure of micro-stack running in pre-mixed gas environment is modified, and the output power of four-cell micro-stack with star-type is increased to 420 mW. Then, the gas supply mode of SC-SOFC micro-stack is also improved step by step combined with the numerical simulation of computational fluid dynamics, and a single-channel/multi-point gas supply mode and a double-channel/multi-point gas supply mode are proposed. The output power of a single SC-SOFC micro-stack module is as high as 8.178 W. In addition, either external series or parallel connection of the micro-stack module, and the experimental verification with the burners are carried out. The results show that SC-SOFC can be easily connected into micro-stack module which produce several watts of output power, and are expected to be used in the combined heat-power system with heat supply prior in the future. By means of the simultaneous measurements of in situ resistance and open circuit voltage, it is also clarified that the repeated oxidation-reduction cycle of Ni at CH₄-O₂ atmosphere is the primary mechanism for the irreversible decay in SC-SOFC. This discovery later has promoted a new technology for the preparation of porous metals by oxidation-reduction method.