Zn Doped LSCF as a Novel Cathode Material for Solid Oxide Fuel Cell

Abstract

Effect of zinc (Zn) dopant on the conductivity, catalytic activity and the interface matching of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ(LSCF) cathode materials with 8YSZ electrolyte were investigated for intermediate temperature solid oxide fuel cell's (IT-SOFC). XRD patterns of powders showed pure perovskite phase after being calcined at 1100°C for 2 h. Substitution of Zn at B-site decreased the TEC(13.7×10⁻⁶ K⁻¹) and polarization resistance (0.15 Ω-cm²). Higher exchange current density of 330mA/cm² was achieved in air, suggesting that LSCZF system of compounds provide high cathodic reaction zoned junctions and numerous diffusing pathways for oxygen ions to access triple phase boundary. The performance of La_0.6Sr_0.4Co_0.04Zn_0.16Fe_0.8O_3-δ, such as thermal expansion coefficient, polarization resistance, catalysis activation are superior to those of LSCF and are sufficient for application as cathode material for solid oxide fuel cell (SOFC).

Keywords:

• conductivity
• thermal expansion
• polarization resistance
• cathode and SOFC

Acknowledgments

Authors are thankful to National Science Council of Taiwan for financial support through Project No: NSC 96-2221-E-011-077 and NSC 97-2221-E-011-006. One of the author thanks to the Director of ARCI, India for giving a chance to present the work at ICE2009.