Investigation on thermal, electrical, and electrochemical properties of scandium-doped Pr0.6Sr0.4(Co0.2Fe0.8)1-x)ScxO3-δ as cathode for IT-SOFC

A systematic study and evaluation were performed on the effect of scandium doping at the B site of Pr0.6Sr0.4(Co0.2Fe0.8)(1-x))ScxO3-delta (PSCF) on key material properties as cathode for intermediate temperature solid oxide fuel cells (IT-SOFC). The doped products Pr0.6Sr0.4(Co0.2Fe0.8)(1-x))ScxO3-delta (PSCFSx, x=0.0-0.2) retained perovskite structure confirmed by X-ray diffraction, and their particles were smaller than the non-doped materials as evidenced by TEM. The electrical conductivity (EC) of PSCFS decreased with increasing Sc3+ content, but EC values were still larger than 100 S cm(-1) in temperature range of 300-800 degrees C as x <= 0.1. The thermal expansion coefficients (TEC) of PSCFS were observed to generally decrease with increasing x especially at lower temperature range of 50-600 degrees C. In addition, the AC impedance revealed better electrochemical performance of PSCFS cathode as x <= 0.1 than that of the undoped sample PSCF. Therefore, PSCFSx (x <= 0.1) shows some potential as cathode electrode for IT-SOFC. The function of Sc3+ dopant was tentatively elucidated and discussed. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.