Solid oxide fuel cells fueled with reduced Fe/Ti oxide

Abstract

For the first time, a Fe–Ti–O containing pellet, a viable chemical looping particle, was used as a solid fuel for direct contact with the Ni/YSZ anode surface of a solid oxide fuel cell. A maximum power density of 97 mW cm⁻², corresponding to 84% of that in the H₂ fuel, was produced using Fe–Ti–O in an inert Ar gas environment at 750 °C. The Fe–Ti–O pellets were able to generate stable electricity under repeated electrochemical oxidation and hydrogen reduction cycles. Temperature-programmed oxidation–reduction coupled with infrared spectroscopic studies revealed that the oxidation of the Fe–Ti–O pellet followed a shrinking core model; the reduction followed a progressive-conversion model. The ability of the Fe–Ti–O pellet to generate electricity on the Ni/YSZ surface can be attributed to its low resistivity (<17 Ω cm) which allows electrons to transport from the electrochemical oxidation sites to the anode surface. This study demonstrates that coupling a SOFC with an external reducer using Fe–Ti–O, an oxygen carrier, is a good candidate for electricity generation.