掺杂氧化铈修饰的镧锶钴铁固体氧化物燃料电池阴极的耐铬性及其机理

Solid oxide fuel cell (SOFC) is a clean and high efficiency energy conversion device. During the long term test in SOFC stacks, chromium deposition usually takes place on the traditional cathode materials, such as La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), due to the presence of chromium alloy interconnect. The chromium deposition seriously increases the overpotential of the cathode and reduces the output power of the stacks. In this project, surface modification with doped-CeO2 nano particles on LSCF is used by impregnation method. The optimization of impregnation process is studied, in order to obtain good microstructure, high electrochemical catalytic activity and high chromium tolerance of the cathode. The surface properties, electrode reaction process and chromium tolerance of the cathode after modification are systematically investigated, which could provide theoretical and experimental basis for the development of high electrochemical activity and high chromium tolerance of LSCF-based cathode.

固体氧化物燃料电池(SOFC)是一种绿色高效的能源转化装置。在SOFC电池堆长期工作条件下，由于铬合金连接材料的存在典型的阴极材料如Sr、Co共掺杂的铁酸镧 La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)，容易出现铬沉积，从而降低阴极的电化学催化活性，表现为阴极极化电阻的上升和电池输出功率的降低。本项目拟采用浸渍法，对LSCF阴极进行表面修饰，淀积掺杂的氧化铈纳米颗粒，通过优化浸渍工艺，以期获得良好的微观结构，从而提高电化学催化活性和耐铬性。同时，系统地研究纳米粒子对LSCF的表面性质、电极反应过程及耐铬性的影响机制，为发展高电化学活性的、高耐铬性的LSCF基阴极提供理论和实验基础。

本项目按照研究计划发展高活性、耐铬性的固体氧化物燃料电池阴极材料,已完成的主要工作有：（1）发展氧离子导体修饰的电极催化剂纳米复合阴极，实现高的电化学活性。通过电导弛豫技术，揭示氧离子导体和电极催化剂间的协同增强机制；（2）通过研究铬在电极和电解质表面的沉积过程，探讨氧离子导体修饰电极催化剂纳米复合阴极的耐铬性作用机制；（3）发展了类钙钛矿型阴极材料体系，由于晶体中不含碱土金属，类钙钛矿材料体现了较高的耐二氧化碳和耐铬毒化的能力。本项目加深了对高活性、耐铬性阴极材料的理解，为固体氧化物燃料电池的实际应用提供理论和实验依据。