• Marina, Olga A.
• Meinhardt, Kerry D.
• Nguyen, Carolyn D.
• Pederson, Larry R.
• Coffey, Greg W.
• Thomsen, Ed C.
• Williams, Mark C.

Abstract

The performance of several negative (fuel) and positive (air) electrode compositions for use in reversible solid oxide fuel cells (SOFC) that are capable of operating both as a fuel cell and as an electrolyzer was investigated in half-cell and full-cell tests.Negative electrode compositions studied were a nickel/zirconia cermet (Ni/YSZ) and lanthanum-substituted strontium titanate/ceria composite, whereas positive electrode compositions examined included mixed ion and electron-conducting lanthanum strontium ferrite (LSF), lanthanum strontium copper ferrite (LSCuF), lanthanum strontium cobalt ferrite (LSCoF), and lanthanum strontium manganite (LSM).While titanate/ceria and Ni/YSZ electrodes performed similarly in the fuel cell mode in half-cell tests, losses associated with electrolysis were lower for the titanate/ceria electrode.Positive electrodes all gave higher losses in the electrolysis mode when compared to the fuel cell mode.This behavior was most apparent for mixed-conducting LSF, LSCuF, and LSCoF electrodes, and discernible but smaller for LSM; observations are consistent with expected trends in the interfacial oxygen vacancy concentration under anodic and cathodic polarization. Full-cell tests conducted for cells with a thin electrolyte (7 um YSZ) similarly showed higher polarization losses in the electrolysis than fuel cell direction.

Topics

• nickel
• Oxygen
• Strontium
• composite
• copper
• Lanthanum
• cobalt
• interfacial
• vacancy