Synthesis and Electrical Properties of Strontium Titanate-Based Materials for Solid Oxide Fuel Cells

摘要

A strontium titanate (SrTiO3)-based material with a perovskite structure is considered to be one of the promising alternatives to LaCrO3-based interconnect materials, since SrTiO3 perovskite shows high chemical stability under both oxidizing and reducing atmospheres at high temperatures. In this work, La-doped SrTiO3 materials with 'stoichiometric' and 'Sr- deficient' compositions were synthesized by the modified Pechini method. The synthesis parameters such as the chelating agent-to-metal ratio and the post-heat-treatment temperatures were controlled to prepare nano-sized, single-phase particles. Electrical, thermal and mechanical properties were determined on the 'stoichiometric' and 'Sr- deficient' materials sintered in an oxidizing atmosphere. Furthermore, a thin layer interconnect was coated on the porous Ni-YSZ anode support by using a screen printing process. The process parameters were optimized to obtain a dense interconnect and to form adherent interfaces between the interconnect and the anode support. The experimental results indicate that Sr-deficient, La-doped SrTiO3 is a promising candidate for interconnect applications in high temperature SOFCs because it shows high electrical conductivity and sinterability as well as thermal expansion match with the other cell components.