Electrochemical performance of mixed ionic-electronic conducting oxides as anodes for solid oxide fuel cell

摘要

Mixed ionic-electronic conducting (MIEC)oxides, SrFeCo0.5Ox, SrCo0.8Fe0.2O3-δ andLa0.6Sr0.4Fe0.8Co0.2O3-δhave been synthesized andprepared on yttria-stabilized zirconia as anodesfor solid oxide fuel cells. Power outputmeasurements show that the anodes composed of suchkinds of oxides exhibit modest electrochemicalactivities to both H2 and CH4 fuels, givingmaximum power densities of around 0. I W/cm2 at950℃. Polarization and AC impedance measurementsfound that large activation overpotentials andohmic resistance drops were the main causes forthe relative inferior performance to the Ni-YSZanode. While interlayered with an Ni-YSZ anode, asignificant improvement in the electrochemicalperformance was observed. In particular, for theSrFeCo0.5Ox oxide interiayered Ni-YSZ anode, themaximum power output reacheso.25 W/cm2` on CH4,exceeding those of both SrFeCo0.5Ox and the Ni-YSZ,as anodes alone. A synergetic effect ofSrFeCo0.5Ox and the Ni-YSZ has been observed.Future work is needed to examine the long-termstability of MIEC oxide electrodes under a very reducing environment.