Electrochemical performance and stability of La0.2Sr0.8Ti0.9Ni0.1O3-δ and La0.2Sr0.8Ti0.9Ni0.1O3-δ - Gd0.2Ce0.8O2-δ anode with anode interlayer in H2 and CH4

Abstract

Donor-doped SrTiO3 is a promising material for use as an alternative anode to solve stability problems due to carbon coking or Ni coarsening etc. of conventional Ni-cermet anodes. Electro-catalytic Ni nanoparticles can be produced in La and Ni co-doped SrTiO3 or La0.2Sr0.8Ti0.9Ni0.1O3-δ (LSTN) anode when it is exposed to a reducing atmosphere. In this work, we study the effects of Gd0.2Ce0.8O2−δ (GDC) either as an anode interlayer (between anode and electrolyte) or as a composite phase in an anode composed of La and Ni co-doped SrTiO3 (La0.2Sr0.8Ti0.9Ni0.1O3-δ, LSTN). The electrochemical performance (i.e., impedance spectra and power density) of electrolyte-supported cells in which scandia-stabilized zirconia (ScSZ) is used as an electrolyte and LSTN or LSTN-GDC is used as the anode, are examined and compared at 800°C in H2 and CH4 fuels. LSTN anode was stable and had improved performance in both H2 and CH4 fuels when GDC was composited and also used as an anode interlayer. A significant reduction of anodic polarization resistance in CH4 gas is clearly demonstrated.