A functional layer for direct use of hydrocarbon fuel in low temperature solid-oxide fuel cells

摘要

Solid-oxide fuel cells (SOFCs), which consist of ceramic components, directly convert the chemical energy of a fuel into electrical energy with the highest efficiency among various kinds of fuel cells. Because SOFCs are operated at high temperatures, typically in excess of 700 ℃, direct use of hydrocarbon fuel becomes possible, which minimizes the system size as well as reducing the cost. It is, however, difficult to utilize direct reforming of hydrocarbon fuel when the operating temperature is below 600 ℃, which is the target for intermediate temperature SOFCs. Here, we report a new concept of an SOFC utilizing a functional layer on the surface of an anode, for the direct reformation of a hydrocarbon fuel using a micro-tubular design. Preparation of the functional layer is cost-effective and the cell with a pure-ceria (CeO_2) functional layer was successfully fabricated. The cell displays practical cell performance below 500 ℃ using methane-water mixture as the fuel gas, and shows enhanced performance compared to systems without a functional layer.