Enhanced electrochemical performance and durability for direct CH4–CO2 solid oxide fuel cells with an on-cell reforming layer

Abstract

Coking is a major issue with the traditional Ni-based anodes when directly oxidizing CH4 in solid oxide fuel cells (SOFCs). Dry reforming to convert CH4–CO2 into CO–H2 syngas before entering Ni-based anode may potentially be an effective and economical method to address the coking problem. Consequently, an on-cell reforming layer outside the Ni-based anode is expected to offer a unique solution for direct CH4–CO2 SOFCs without coking. In this study, Ni-GDC anode-supported cells with and without a Sr2Co0.4Fe1.2Mo0.4O6-δ (SCFM) layer outside the anode support have been fabricated and evaluated using either H2 or CH4–CO2 as fuel. Both types of cells show excellent electrochemical performance when H2 is used as fuel, and the SCFM layer has negligible impact on the cell performance. When CH4–CO2 is used as fuel, however, the electrochemical performance and durability of the cells with the SCFM layer are much better than those without the SCFM layer outside the Ni-GDC anode, indicating that the SCFM layer can efficiently perform dry reforming. This unique on-cell dry reforming design enables direct CH4–CO2 solid oxide fuel cells and offers a very promising route for energy storage and conversion.