Highly conducting perovskite structured (M-SrCoFe-O3-δ, M = Ce, Ba) cathode for solid oxide fuel cell

Abstract

The perovskite structured cathode Ce0.5Sr0.5Co0.8Fe0.2 O3-δ (CSCF1), Ce0.4Sr0.6Co0.7Fe0.3O3-δ (CSCF2), Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF1) and Ba0.4Sr0.6Co0.7Fe0.3- O3-δ (BSCF2) powders are synthesized by sol-gel process using nitrate based powder chemicals for the synthesis of perovskite structured cathode for SOFCs applications. Cerium is used for the first time on A site of perovskite materials and considered to be more promising cathode material for SOFC. The synthesized powders are characterized by XRD, SEM, FT-IR, TGA and conductivity test. XRD results exhibited the formation of perovskite phase. From SEM, it is found that samples are homogeneous and calculated particle size is found as 685 nm, 917 nm, 691 nm and 689 nm for CSCF1, CSCF2, BSCF1 and BSCF2 respectively. In order to study the stability of the prepared materials TGA is conducted at temperature range from 25 °C to 1000 °C. TGA results showed negligible weight loss present in CSCF1. Conductivity values obtained from conductivity test of above said prepared samples were 22.878, 0.078, 0.31 and 0.156 Scm−1 respectively. In particular, the Ce0.5Sr0.5Co0.8Fe0.2O3-δ (CSCF1) showed the maximum conductivity value of 22.878 Scm−1 at 600 °C in air measured by DC 4-probe method, which is much higher as compared to conductivity values of all other prepared samples. The fuel cell performance is carried out by using CSCF1 as cathodes, LiNiCuZn-oxide as anode and SDC-carbonate as electrolyte. By taking all these factors into account, the CSCF1 is found to be the optimal composition, which lead to the peak conductivity and highest power density as compared to other samples.