Power generation characteristics of a SOFC with a Ni/YSZ anode incorporating a SrZr_0.95Y_0.05O_3-α proton conductor

Abstract

In order to improve the performance and stability of anodes for solid oxide fuel cells (SOFCs) under low hydrogen concentration conditions, SrZr_0.95Y_0.05O_3-α (SZY) proton conductor particles were incorporated into the conventional Ni/YSZ anode. Power generation experiments were conducted using the electrolyte-supported single cells with conventional Ni/YSZ and Ni/YSZ-5%SZY anodes. Enhanced output power density under low hydrogen partial pressure conditions was achieved with the modified anode. This enhancement is ascribed to a decline in the anode overpotential of the Ni/YSZ-5%SZY anode, estimated from impedance spectra, compared to that of the conventional Ni/YSZ anode. In addition, the amount of hydrogen adsorption on Ni, YSZ, and SZY was measured using thermal desorption spectroscopy (TDS). This revealed that the proton conductor SZY could adsorb a large amount of hydrogen compared with YSZ. Consequently, the SZY proton conductor may play an important role in the supply/storage of adsorbed hydrogen, or in increasing the oxidation resistance of Ni under low hydrogen concentration conditions.