Gd(1-x)A(x)Mn(1-y)Co(y)O(3-delta) (A = Sr, Ca) as a cathode for solid-oxide fuel cells

Abstract

The Gd(1-x)A(x)Mn(1-y)CO(y)O(3-delta) (A = Sr, Ca) systems were examined as a cathode for use in solid oxide fuel cells. The electrical conductivity and cathodic polarization on an 8 mol % yttria-stabilized zirconia (8YSZ) electrolyte had acceptable values for certain compositions. Thermal expansion measurements were taken, showing compatibility of Mn-rich compositions with the 8YSZ electrolyte. Reactivity with 8YSZ revealed the formation of SrZrO3 or CaZrO3 at lower temperatures for high Co containing compositions. No reaction product was detected between Gd0.8Ca0.2Mn1-yCoyO3-delta and 8YSZ. However, significant diffusion of Co into 8YSZ was found at the Gd0.8Ca0.2Mn0.4Co0.6O3-delta/8YSZ interface after annealing at 1200 degrees C for 24 h. (C) 1999 The Electrochemical Society. S0013-4651(98)10-031-9. All rights reserved.