Enhancement of electrochemical performance for proton conductive solid oxide fuel cell by 30%GDC-LSCF cathode

In proton conducting solid oxide fuel cell (H-SOFC), the primary reaction occurs at the three-phase reaction boundary where protons, electrons and oxygen ions meet. In the present study, an oxygen ion conductor, Gd0.1Ce0.9O2-δ(GDC), added La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) as a cathode for anode-supported H-SOFC with BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) as the electrolyte. The addition of GDC could increase the oxygen vacancy concentration and three-phase reaction interface, which improved the adsorption and dissociation rate of oxygen, but led to the decrease of conductivity and the decrease of charge transfer rate. The single-cell with LSCF-30GDC cathode presented outstanding performance, and the maximum power density (MPD) was 56% higher than that of LSCF at 650 °C, while the performance of the cell with 50%GDC only increased by 10%, indicating that 30% GDC was the most suitable doping amount. The superb performance and stability imply that the LSCF-GDC composite material is a promising substitute cathode for H-SOFCs at low temperatures.