Performance and durability of Ni-coated YSZ anodes for intermediate temperature solid oxide fuel cells

Abstract

NiO-coated YSZ composite powders were synthesized through the Pechini process in order to improve the performance and durability of SOFC anodes. Their microstructures and electrical properties have been investigated with thermal and redox cycling tests. The coverage of NiO crystals on the YSZ surface could be modulated by controlling the composition of the reaction mixture and the ratio of NiO and YSZ. Ni-YSZ electrodes were manufactured by sintering the die-pressed NiO-YSZ pellet at 1400 degrees C for 3h, followed by reducing it to 800 degrees C under hydrogen atmosphere. The anode made from NiO/YSZ composite powder, which has a high homogeneity and plenty of contact sites between Ni and YSZ, has an excellent tolerance against thermal and redox cycling. The maximum power density of a single cell made from NiO/YSZ composite powder was 0.56W cm(-2) at 800 degrees C in reactive gases,of humidified hydrogen and air. It can be concluded that the functional NiONSZ composite powder will suppress the degradation of anodes and enhance the long-term and redox stability of the unit cell at elevated temperatures. (c) 2006 Elsevier B.V. All rights reserved.