金属基支撑型固体氧化物电解池研究

Metal supported Solid Oxide Electrolysis Cells（SOEC）have the advantages of lower cost, higher strength, better conductivity for both heat and electricity. It is also possible to use welding, in stead of sealing, to prepare a stack, so as to avoid the anode degradation owing to Si evaporation. However, the stability of SOEC is the key issue for application. The present work is based on our previous work on metal supported Solid Oxide Fuel Cells（SOFC）, and will address the degradation of metal support, anode and cathode under the operating condition of SOEC. The preparation technique of SOEC in the present work is the same as SOFC before, however, the electrodes materials will be modified and optimized for SOEC application. Larger area of cells is also extended. The degradation of the cell itself and the repeating unit as that in a stack will be studied. We will try to record the impedance spectra of the cell and the repeating unit during different testing time, analyze the change of impedance spectra, and try to find the mechanism of degradation, with the help of examinations to the cell and unit after cooling. Modern techniques such as SEM、TEM、EDS、XRD will be applied to connect the degradation to the change in morphology, microstructure, distribution of elements or impurities, etc.. With a better understanding to the degradation mechanism of the cell and unit, people can have theoretical guidance for preparing higher performance SOECs and stacks with good stability. This project has good background of application and is meanwhile rich in scientific content with respect to exploring and solving scientific issues.

金属基支撑固体氧化物电解池（SOEC）成本低廉、强度高、导电性和导热性好；还可采用钎焊替代玻璃陶瓷密封，避免硅杂质挥发污染燃料极。然而,SOEC的稳定性是其应用的关键。本项目以申请人前期研究为基础，重点研究金属支撑体和阳极、阴极在SOEC工作条件下的衰减机制。该SOEC制备方法与前期金属支撑SOFC相同，但电极材料将按SOEC的要求进行调整和优化，电池的面积也将得到扩展。不仅研究电池本身的衰减，也研究电堆重复单元的衰减。通过测试、记录单电池和重复单元的复数阻抗谱随时间的变化，探索衰减机制。对运行后的单电池和重复单元进行SEM、TEM、EDS、XRD等分析测试，比较电极形貌、微结构、元素分布与杂质分布等的变化，明确其与性能衰减之间的关系。阐明衰减机制将对SOEC电池/堆性能的提高和稳定性的改善提供理论指导。本申请既有良好的应用背景，又能发现和解决新的科学问题，拓展SOEC的科学内容。

金属基支撑型固体氧化物燃料电池具有高的热导率、电导率和高的强度，其抗应力特征使得该电池能够快速启动，具有广泛的应用前景。该电池的逆运行SOEC可以实现快速启动的同时，工作温度进一步降低，具有使用低温废热蒸汽，改进电解效率的潜力。.经过本项目的研究，我们基于廉价的不锈钢粉体，采用流延、叠层热压、共烧结的工艺流程，成功得到金属支撑型电解质膜，并探讨了浸渍法制备电极的工艺。所采用的制备方法具有可以工程化放大的潜力，对于未来金属支撑型固体氧化物燃料电池（SOFC）和电解池(SOEC)的产业化应用奠定了基础。.高性能的电极材料是获得高性能电池的有力保障。本项目重点研究了Fe系正极材料，经过掺杂处理后，铁系材料的电导率提高，得到了较好的电化学性能。在负极材料方面，研究了基于钙钛矿结构陶瓷材料的La0.8Sr0.2Cr0.5Mn0.5(LSCrM)负极体系，其经过浸渍CeO2以后，在正极支撑电池上得到了一定的初步性能。该材料虽然活性较低，但在甲烷燃料中表现出了较好的稳定性。.新型的电解质材料具有较高的电导率，可望进一步降低电池工作温度，但是新型电解质材料也存在难以烧结，机械强度较低的缺点。为此，本项目也研究了基于LSGM电解质的对称型电池制备工艺，以及对于质子导体电解质BaZr0.1Ce0.7Y0.2O3-d（BZCY7）的闪烧特性和烧结助剂的影响，得到一些结果。.总之，本项目在制备工艺和新材料探索方面取得了一些有意义的结果，对后续开发产业化的电池提供了重要依据。