The effect of porosity gradient in a Nickel/Yttria Stabilized Zirconia anode for an anode-supported planar solid oxide fuel cell

Abstract

In this paper. a graded Ni/YSZ cermet anode, an 8 mol.%YSZ electrolyte, and a lanthanum strontium manganite (LSM) cathode were used to fabricate a solid oxide fuel cell (SOFC) unit. An anode-supported cell was prepared using a tape casting technique followed by hot pressing lamination and a single step co-firing process, allowing for the creation of a thin layer of dense electrolyte on a porous anode support. To reduce activation and concentration overpotential in the unit cell, a porosity gradient was developed in the anode using different percentages of pore former to a number of different tape-slurries, followed by tape casting and lamination of the tapes. The unit cell demonstrated that a concentration distribution of porosity in the anode increases the power in the unit cell from 76 mWcm(-1) to 101 mWcm(-2) at 600 degrees C in humidified hydrogen. Although the results have not been optimized for good performance, the effect of the porosity gradient is quite apparent and has potential in developing superior anode systems. (C) 2009 Elsevier B.V. All rights reserved.