Barium oxide promoted Ni/YSZ solid-oxide fuel cells for direct utilization of methane

Abstract

Conventional Ni/YSZ solid-oxide fuel cell (SOFC) anodes work well with hydrogen but require modification to tolerate hydrocarbon fuels and not accumulate carbon, which degrades cell performance and eventually damages the anode microstructure. In this work, barium oxide (BaO) was incorporated into Ni/YSZ anodes of SOFC by two different methodologies: impregnation and microwave irradiation. The performance of the BaO incorporated cells was measured in H₂ and CH₄ at 1073 K. With the impregnation technique, BaO was distributed both on Ni and YSZ grains. The BaO was stable on Ni but interacted with YSZ causing a morphological change and volume expansion of YSZ, which is problematic in this solid device. As such, an alternative method, based on microwave irradiation, was developed to selectively deposit BaO only on Ni and minimize the interaction between BaO and YSZ. The anode developed by this microwave irradiation technique showed comparable electrochemical performance in dry CH₄ to that of conventional and impregnated anodes, and lower carbon accumulation than the conventional anode at 1073 K.