High-performance GdBaCo2O5+delta-Ce0.9Gd0.1O1.95 composite cathode for solid oxide fuel cells

Abstract

GdBaCo2O5-delta (GBCO)-Ce0.9Gd0.1O1.95 (CGO) composites with various CGO contents (0-40 wt.%) have been investigated for potential cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The effect of CGO incorporation on the thermal expansion coefficient (TEC), electrochemical performance and microstructure of the GBCO-CGO composite cathodes are investigated. The thermal expansion behavior shows that the TEC values of GBCO cathode decrease with CGO addition. The TEC of 30 wt.% CGO-70 wt.% GBCO (CG30) cathode shows 14.7 x 10(-6) degrees C-1 up to 900 degrees C, which is lower value than pristine GBCO (20.0 x 10(-6) degrees C-1). In addition, the addition of CGO to GBCO cathode improves remarkably the electrochemical performance. The composite cathode of 30 wt.% CGO-70 wt.% GBCO (CG30) coated on Ce0.9Gd0.1O1.95 electrolyte shows the lowest polarization resistance (0.029 Omega cm(2) at 700 degrees C). An electrolyte-supported (300 mm thick) single-cell configuration of CG30/CGO/Ni-CGO attains a maximum power density of 340 and 525 mW cm(-2) at 650 and 700 degrees C, respectively. The results indicate that 30 wt.% CGO-70 wt.% GBCO cathode is a promising cathode material for IT-SOFCs. (c) 2010 Elsevier B.V. All rights reserved.