Development of homogeneous solid electrolyte/electrode structureby chemical vapor deposition method

点击翻译按钮获取中文摘要

Typical fabrication process of making solid electrolyte for the fuel cell is sintering. However it brings the inhomogeneity of cations from the in sufficient mixing of the raw materials and local diffusion during the sintering and also during long time running of power generation. These inhomogeneity is enhanced the large amount of trivalent cation doping, such as 20-30 at%. We proposed the chemical vapor deposition (CVD) using Ce(EtCp)_4 (Ce (C_5H_4C_2H_5)_4) and Gd(EtCp)_3 (Gd(C_5H_4C_2H_5)_3) as the source materials. In this research, we determined the optimum condition of these raw materials for CVD process for low-pressure coldwall-type-CVD apparatus. We succeeded to fabricate the columnar type GDC film on Al_2O_3, SiO_2/Si substrates. It was found that the film was grown at around 300℃ and has columnar structure that means no grain boundary in the out of plane direction. Since thinner thickness of the film and almost no grain boundary along the out of plane direction, oxide ion can be able to diffuse even at 180℃ by AC measurement. New type atmospheric pressure CVD apparatus was developed to grow the film with very fast growth rate. We also tried to fabricated the porous electrodes with dense surface layer for the anode: Ni-GDC and the cathode: LaSrCoO_3-GDC. GDC thin films by low pressure CVD were fabricated on the porous electrodes, and tried to generate the electric power in the H_2-O_2 system. Since the power generation test system is preliminary, but we have several important point to realize the CVD derived electrolyte system.