Highly Durable, Surface Modified SOFCs Running on Hydrocarbon Fuels at 600 °C

Abstract

Fuel flexibility is a unique feature of solid oxide fuel cells (SOFCs), the instability of Ni-based cermet anodes in hydrocarbon fuels impede the advancement of low-temperature solid oxide fuel cells (LT-SOFCs). Here we demonstrate highly stable LT-SOFCs prepared by catalytically modifying the surface of a conductive ceramic oxide, SrFe0.2Co0.4Mo0.4O3 (SFCM), using Ni-GDC nanoparticles (<100 nm). The nano-sized Ni-GDC electrocatalysts, resulting from careful optimization of Ni-to-GDC ratio, and subsequent low-temperature calcination process, enhance the fuel oxidation kinetics and stability of SFCM anode significantly. An optimized Ni-to-GDC ratio of 1:10 on SFCM-supported SOFC delivered peak power density of 0.75, 0.65 and 0.36 W cm−2 at 650 °C, 600 °C and 550 °C, respectively, in humidified H2 and 0.62, 0.39 and 0.22 W cm−2 at 650 °C, 600 °C and 550 °C, respectively, in CH4/H2 gas mixtures, nearly 4× higher than GDC as electrocatalyst. Remarkably, for the same Ni-to-GDC ratio, a stable cell voltage of 0.82 V is maintained over 200 h of operations (under current) at 600 °C in CH4/H2 gas mixtures.