Influence of the ratio between Ni and BaCe 0.9Y 0.1O 3− δ on microstructural and electrical properties of proton conducting Ni–BaCe 0.9Y 0.1O 3− δ anodes

Abstract

Cermet anode substrates Ni–BaCe 0.9Y 0.1O 3− δ (Ni–BCY10) with varied ratios between Ni and BCY10 were prepared. BCY10 powders were prepared by the citrate–nitrate auto-combustion method and anode substrates were prepared by the method of evaporation and decomposition of solutions and suspensions. Sintered anode substrates were reduced and their properties were examined before and after reduction as a function of the ratio between Ni and BCY10. Microstructural properties of the pellets were investigated using X-ray diffraction analysis and field emission scanning electron microscopy. The influence of the Ni:BCY10 ratio on the microstructure of conducting paths through ceramic and metal parts was discussed. Impedance spectroscopy measurements were used for evaluation of electrical properties of the anode pellets. The high conductivity values of reduced anodes confirmed percolation through Ni particles even for an anode with a reduced amount of nickel. Fuel cell tests were carried out in order to examine the influence of the Ni:BCY10 ratio on fuel cell performance and to compare characteristics of cermet anodes with platinum electrodes. The ratio between Ni and BCY10 did have a slight influence on the power output of fuel cells. Fuel cells with a cermet anode demonstrated a higher power output compared to fuel cells with a platinum electrode.