固体氧化物燃料电池薄膜电极的电化学性能及氧还原反应过程研究

Cathode material is a solid oxide fuel cell (SOFC) one of the key component materials, its performance directly affects the output power and cycle stability of the fuel cell system. However, under the intermediate and low temperature (300-600 oC), the oxygen reduction reaction (ORR) catalytic activities for the cathode material decreased significantly, the contact resistance of electrode and electrolyte interface is also obvious increase. Therefore, fabricate of cathode materials with high catalytic activity, to improve oxygen rapid diffusion and transport properties, improve the electrode and electrolyte interface contact become the key to solve the above problems. In this project, to iron base perovskite mixed conductor oxides AFe1-xMxO3-δ (A for alkaline earth Sr, Ba and rare earth elements, M for transition metal Cu, Co, Ni, etc) as the research object, using magnetron sputtering technology, fabricating the nano-porous thin film cathode with particle distribution uniform. Explore the microstructure and interface properties of thin film electrode on the properties of cathode oxygen catalytic mechanism, further study of thin film cathode ORR process. And the influence between the composition, microstructure , preparation technology and electrochemical properties of the thin film electrode is clarified, can provide the theory basis for the design and development of cathode materials with high catalytic activity and high cycle stability for intermediate and low temperature SOFC.

阴极材料是固体氧化物燃料电池（SOFC）的关键材料之一，其性能直接影响到整个燃料电池系统的输出功率和循环稳定性。然而在中低温（300-600 oC）工作条件下粉体阴极材料的氧还原反应（ORR）催化活性显著下降，电极与电解质界面的接触电阻也明显增加。因此，构筑具有高催化活性的阴极材料，来提高氧快速扩散与输运性能、改善电极与电解质界面接触成为解决上述问题的关键。本项目以铁基钙钛矿混合导体氧化物AFe1-xMxO3-δ (A为碱土元素Sr, Ba; M为过渡金属Cu, Co, Ni等)为研究对象，拟采用磁控溅射技术，构筑粒子分布均匀的纳米多孔薄膜阴极。探索薄膜电极的微观形貌和界面特性对阴极氧催化性能的作用机制，深入研究薄膜阴极的ORR过程。阐明薄膜电极的组成、显微结构及电极制备工艺与电化学性能的影响规律，为开发高催化活性且循环稳定性高的中低温SOFC阴极材料提供理论依据。

项目采用固相法和甘氨酸－硝酸盐技术制备Bi0.5Sr0.5FeO3-δ及Ba0.95La0.05FeO3基钙钛矿结构阴极催化剂，考察电极不同氧空位浓度和晶体结构对其电催化性能的影响，并研究阴极上氧还原反应的电化学过程和抗CO2耐受性。通过低价态Ni或Cu的掺杂来增加电极的氧空位浓度，来改善电极的氧输运性能，通过高价态及高酸性Nb、Ta和Mo的掺杂来改善电极的抗CO2耐受性。项目研究电极催化剂的结构与氧缺陷类型对材料电催化剂性能的影响，考察研究阴极氧反应动力学过程，为开发高性能电催化材料的提供理论依据。