Symmetrical solid oxide fuel cells based on titanate nanocomposite electrodes

Abstract

Nanocomposite electrodes of (Sr0.7Pr0.3)0.95TiO3±δ−Ce0.9Gd0.1O1.95 are directly prepared by spray-pyrolysis deposition on Zr0.82Y0.16O1.92 electrolytes and their properties are compared with those obtained by the traditional screen-printing powder method. The structural, microstructural and electrical characteristics are investigated for their potential use as both cathode and anode in Solid Oxide Fuel Cells. The nanocomposite electrodes with reduced particle size ∼30 nm achieved a polarization resistance at 700 ºC of 0.50 and 0.46 Ω cm2 in air and pure H2, respectively, outperforming those obtained for the analogous screen-printed electrodes with particle size of 450 nm, i.e. 4.8 and 3.9 Ω cm2, respectively. An electrolyte-supported cell with symmetrical electrodes reached a maximum and stable power density of 354 mW cm-2 at 800 ºC. These results demonstrate that the performance of electrode materials with modest electrochemical properties but high phase stability, such as doped-SrTiO3, can be highly improved by preparing nanocomposite electrodes directly on the electrolyte surface.