Strongly coupled oxygen reservoir enabled highly efficient solid oxide fuel cell cathode operation under harsh conditions

Abstract

The field distribution of oxygen concentration in cathode areas in planar type solid oxide fuel cell stack seriously affects power output, especially at the outlet of/beneath the interconnector where oxygen supply suffers from shortage. A new in-situ solvothermal growth method is applied to prepare gadolinium doped cerium oxide (GDC) nano particles decorated lanthanum strontium cobalt ferrite (LSCF) heterostructure cathode (LSCF@GDC) which performed well under a wide oxygen partial pressure range (0.03–0.21 atm). The cathode shows enhanced specific surface area and improved sintering activity, yielding stronger cathode/electrolyte interface contact. Specifically, the cell equipped with LSCF@GDC cathode demonstrates 40-fold promoted performance under low oxygen partial pressures ( p O 2 = 0.03 a t m ) e.g. 0.415 W/cm 2 for LSCF@GDC versus 0.0107 W/cm 2 for bare LSCF at 750 °C. The systematic characterizations verify that the strong coupling effect between GDC and LSCF, i.e., the GDC serves as the oxygen reservoir to not only alter the crystal structure of LSCF with enhanced oxygen content, but also guarantee sufficient oxygen species for LSCF under oxygen-starving atmosphere. Simultaneously, the oxygen-abundant cathode surface and optimized interface are considered to collectively contribute to the improved electrochemical performances and enable efficient operation. • LSCF@GDC heterostructure cathode is constructed via solvothermal method. • SOFC performance improvement by 40-fold under oxygen partial pressure of 0.03 atm. • Oxygen reservoir effect due to surface anchored GDC nano particles is verified.