Preparation and electrical properties of cathode material based on zinc-doped Sr2Fe1.5Mo0.5O6 for solid oxide fuel cells

A novel solid oxide fuel cell cathode material based on Zn-doped Sr2Fe1.5Mo0.5O6 is synthesized by combustion method. The structural, chemical compatibility, and electrochemical properties are investigated. Results show that Sr2Fe1.5-xZnxMo0.5O6-delta (SFZnxM) retains the perovskite structure when Fe element in Sr2Fe1.5Mo0.5O6 is partially replaced by Zn. The thermal expansion coefficient of Sr2Fe1.5Mo0.5O6 increases with Zn doping remarkably, so doping with excessive Zn is detrimental to the chemical compatibility of SFZnxM cathode with gadolinium-doped ceria (GDC) electrolyte. The conductivity of Sr2Fe1.5Mo0.5O6 is improved by doping with appropriate content of Zn, and the maximal electrical conductivity of 27.3 S cm(-1) at 450 degrees C is measured for the Sr2Fe1.45Zn0.05Mo0.5O6-delta cathode. Electrochemical performance of symmetrical cell with configuration of SFZnxM/SDC/SFZnxM are evaluated using wet H-2. The symmetrical cell with the structure of SFZn0.05M/SDC/SFZn0.05M shows the maximum power density of 636 mW cm(-2) at 800 degrees C. As a result, Sr2Fe1.5-xZnxMo0.5O6-delta is a potentially cathode material for solid oxide fuel cells.