氧化铈-碳酸盐复相材料H+/O2-导电特性及高效电解制氢性能

掺杂氧化铈-碳酸盐复相材料作为一种非常有潜力的低温固体氧化物燃料电池（SOFC）电解质而备受关注。但是，对于该材料的多离子导电行为研究相对其SOFC应用研究却相对滞后。离子导电机理还没有形成统一的认识，甚至形成相反的结论。本项目申请拟提出与燃料电池操作气氛很接近的电解池技术来研究该复相材料的混合氧离子（O2-）和质子（H+）导电特性。探讨复相材料的制备方法、微观结构（粉末颗粒大小、界面结构）、操作气氛与电解性能（极化曲线、阻抗谱、活化能、离子迁移数）的关系，确定具有高电解效率的复相材料制备方法和电池构筑工艺。结合阻抗等效电路模型和连续通道渗透模型理论探讨离子导电途径、离子相互作用和多离子导电机理。本项目涉及SOFC中复相离子导电材料所产生的共性问题，对于开发低温高离子导电材料和提高系统稳定性等关键问题具有重要意义，研究结果也将推动电解制氢技术的发展，为我国能源的高效清洁利用做出贡献。

The ceria-carbonate composite has been considered as a potential electrolyte for low temperature solid oxide fuel cell (SOFC) due to its excellent ionic conductivity and unique hybrid ionic conduction property. However, the fundamental study of its hybrid ionic conduction behavior is much delayed compared with the application for SOFC. Especially, the ionic conduction mechanism does not form a consensus. Instead, some contrary results have been reported in the open literature. In this proposal, we will use the electrolysis cell, a reverse process of fuel cell, to examine the hybrid ionic (H+ and O2-) conduction characteristics of this prospective composite material. The effect of the synthesis methods, material microstructure and the operational atmospheres on the electrolysis properties including the polarization curves, electrochemical impedance spectroscopy, the activation energy and ionic transport number are investigated to identify suitable synthesis method and cell fabrication technology for effective electrolysis operation. The equivalent circuit mode and continuous percolation mode theories are employed to discuss the possible ionic transport channel, the interaction and multi-ionic conduction mechanism of the composite electrolyte. The research relates to the general characteristics of the composite materials for highly efficient SOFC, the results will play a significant role in developing high ionic conducting materials and improving the system stability for low temperature operation, it will also advance the evolution of the electrolysis technology, and contribute the energy efficiency for China developing.