中温燃料电池陶瓷-碳酸盐复合电解质：结构控制、离子传导机理及单电池构建

Solid oxide fuel cells with high energy converting efficiency are promising solutions to energy crisis and environmental pollution. However, their practical application is restricted by the high operating temperature (800-1000 oC). The key to solving this problem is to develop new electrolyte materials which are applicable in 400-700 oC. Samarium doped ceria (SDC)-carbonate composite electrolytes present high ionic conductivities in the intermediate temperature region, and single cells based on them exhibit excellent performances. Nevertheless, the distribution of the SDC and the carbonate phases in composite electrolytes has not been well controlled, leading to a poor stability of the electrolyte. Besides, the ionic conducting mechanism inside the composite electrolyte is not well clarified. Some preliminary studies on the ionic conduction in the composite electrolyte have been carried out in our laboratory. In this project, composite electrolyte membranes will be prepared through “template-impregnation” method, by which the distribution of SDC and carbonate phases would be controlled. The influencing factors of proton and oxide ionic conductivities will be investigated. The effect of the interface on the ionic conduction and its mechanism will be studied. The co-conducting model of ions through the composite electrolyte will be built and single cells with composite electrolytes will be fabricated. This project aims to reveal the ionic conducting path and mechanism in the composite electrolyte, which is the basis for the selection of electrolyte materials, the optimization of the fuel cell structure, and then the improvement of the single cell performance.

具有高能量转换效率的固体氧化物燃料电池能够有效缓解能源危机和环境污染，但过高的操作温度（800-1000℃）限制了它的实际应用。开发适用于400-700℃的电解质材料是解决这一问题的关键。钐搀杂氧化铈（SDC）-碳酸盐复合电解质在中温范围内具有高离子电导率，相应的燃料电池也具有良好的性能。但目前对复合电解质的研究并未控制SDC相和碳酸盐相的分布，导致其稳定性较差，各离子在其内部的传导机理也有待研究。我们已对复合电解质中的离子传导进行了初步考察。本项目通过模版-浸渍法制备复合电解质膜，控制两相的分布方式，提高稳定性；考察质子、氧离子电导率的影响因素；研究两相界面对离子传导的促进作用和机理；提出复合电解质中多离子共传导模型；基于复合电解质构建单电池。本课题的目的在于揭示各种离子在复合电解质中的传导途径和传导机理，为电解质材料的选择和电池结构的优化，进而提高燃料电池性能提供理论依据。

固体氧化物燃料电池（SOFC）的能量转换效率高、污染低，是缓解环境污染和能源危机的有效途径。但过高的操作温度限制了传统SOFC的大规模应用。钐掺杂氧化铈（SDC）—碳酸盐复合电解质材料在中温范围内具有较高的离子电导率，是降低SOFC工作温度的理想选择。本项目致力于对复合电解质中陶瓷相和碳酸盐相的分布进行调控，从而提高电解质的离子电导率和稳定性，同时开发与之匹配且具有高电化学催化活性的电极材料，以降低SOFC的操作温度，同时使用非氢燃料。这对我国经济的可持续发展具有重要的意义和应用前景。.项目取得多项研究成果，包括：（1）通过模板法制备了具有均匀孔道分布的SDC陶瓷材料，揭示了多孔陶瓷基体结构的影响因素；通过熔盐浸渍法制备了具有高离子电导率和稳定性的SDC-锂钠碳酸盐复合电解质膜；提出了各类离子在复合电解质中的传导机理。（2）基于复合电解质膜，开发了一系列金属陶瓷阳极和金属氧化物阳极材料；考察了碳氢燃料在阳极的电化学反应机理；通过优化阳极组成，提高阳极催化活性和抗积碳能力，从而提高单电池的性能和稳定性。（3）将复合电解质材料应用于其他领域，如直接碳燃料电池、单部件燃料电池和高温二氧化碳分离膜等，均取得了良好的性能。.在项目执行期内共发表SCI论文12篇，培养博士毕业生3人，硕士毕业生1人。