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

摘要

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, Gd_(0.1)Ce_(0.9)O_(2-δ)(GDC), added La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ) (LSCF) as a cathode for anode-supported H-SOFC with BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-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 ℃, 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.