The effect of Fe2O3 sintering aid on Gd0.1Ce0.9O1.95 diffusion barrier layer and solid oxide fuel cell performance

Solid oxide fuel cells (SOFCs) with the Gd0.1Ce0.9O1.95 (GDC) diffusion barrier layer require the densification of GDC to improve the performance of the cells. In this work, the addition of 0.5 mol% Fe2O3 in GDC diffusion barrier layer as sintering aid is studied. The symmetrical cell and the fuel cell are fabricated by hot-pressing, co-sintering and screen-printing technologies. It is found that the addition of Fe2O3 can make GDC barrier layer denser at a reduced sintering temperature of 1250 °C and prevent diffusion of Sr to form ionic insulating interface between YSZ (Y2O3 stabilized ZrO2) and La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF). The fuel cell based on the GDC-Fe2O3 barrier layer achieves better maximum power density of 0.89 W cm−2 at 800 °C than that of 0.68 W cm−2 without Fe2O3 addition. No obvious degradation was observed on fuel cell based on the GDC-Fe2O3 diffusion barrier layer after a stability test at 750 °C for 100 h under 0.75 V and the thermal cycling between 750 and 400 °C. The results indicate that the addition of Fe2O3 sintering aid in GDC diffusion barrier layer can promote the densification of GDC and exhibit good long-term stability and thermal cycle stability.