Enhanced electrochemical performance of metal-supported solid oxide fuel cells via an inner coating of Gd_0.1Ce_0.9O_2-Δ nanosol in the porous NiFe-metal support

The effects of applying an inner coating of nanosized gadolinium-doped ceria, Gd_0.1Ce_0.9O_2-δ, sols on the porous NiFe-metal support for solid oxide fuel cell application are investigated. The GDC nanosols are synthesized by a sol-gel method using metal-alkoxide precursors and the Ni/Fe ratio of metal support is optimized. Field-emission transmission electron microscope reveals that the synthesized sols have particle size of 2–3 nm. Metal supports based on alloys composed of Ni and Fe are used in this work, and the ratio of Ni/Fe is optimised. In case of Ni/Fe ratio of 9:1, high porosity (≥ 57%) metal supports are obtained and the physico-chemical compatibility between the NiFe-metal supports and the Ni-GDC anodes is improved. The I-V results demonstrate a remarkable improvement in the power density of the GDC nanosol-coated button cell (677 mW cm⁻²) compared to that of the uncoated cell (437 mW cm⁻²) at 650 °C. The total area specific resistance after the coating GDC nanosols significantly decrease from 0.226 Ω cm² to 0.125 Ω cm². These results reflect that GDC nanosols play an important role in reducing the resistances due to the effective expansion of the triple phase boundary and the improved connectivity of the ionically conductive phase.