SYNTHESIS OF LAxSR1-xTIO3 ANODE MATERIALS BY SOL-GEL AUTO-COMBUSTION METHOD

Abstract

ABSTRACT A novel anode material for intermediate temperature solid oxide fuel cells with a composite of La x Sr 1-x TiO 3 has been synthesized by a sol-gel auto-combustion method. X-ray diffraction (XRD) shows that La x Sr 1-x TiO 3 has good chemical compatibility with Gd 0.2 Ce 0.8 O 1.9 electrolyte. The thermal expansion coefficient (TEC) of the as-prepared anode material is similar to that of Gd 0.2 Ce 0.8 O 1.9 . The electric conductivity measurements show that the conductivity of La x Sr 1-x TiO 3 increases with the increasing of lanthanum contents and reached a maximal value at x=0.3. At 800 o C, the electrical conductivity of La 0.3 Sr 0.7 TiO 3 is 184S·cm -1 . Keywords: Fuel cells; Electrode materials; Chemical synthesis; X-ray diffraction 1. INTRODUCTION Solid oxide fuel cells (SOFCs) are currently regarded as one of new energy conversion systems because of their high efficiency, environmentally friendly technology and fuel flexibility [1]. However, SOFCs still have many problems related to its longevity or long term stability due to its high operation temperature, and the majority of current researches is concentrated on the development of intermediate temperature SOFCs (IT-SOFCs) [2,3]. Recently, there are intensive studies on the anode of solid oxide fuel cells, and Ni-cermet composites are the most commonly used materials as anodes for IT-SOFCs [4-6]. Traditional Ni-yttria stabilized zirconia (Ni/YSZ) anodes have been used in SOFCs for decades. Although nickel is an excellent catalyst for hydrogen oxidation and good electrical current conductor, Ni-based anodes are likely to suffer structural damage when cycled repeatedly in oxidizing and reducing atmospheres [7-10]. Therefore, research and development of new anode materials have received much attention previously. Perovskite-type oxide materials have attracted many attentions as IT-SOFCs anodes due to their mixed-conducting characteristics and higher ion-conductivity in the intermediate temperature range [11-13]. Among those perovskite-type oxides, SrTiO