High-performing and stable electricity generation by ceramic fuel cells operating in dry methane over 1000 hours

Developing a reliable and high-performing direct hydrocarbon symmetric solid oxide fuel cells (SSOFCs) is promising to achieve the simple and durable operation in natural gas. Here we demonstrate a durable SSOFC with a ceramic oxide material simultaneously used as symmetric electrode that performs outstandingly in dry methane at anode side and ambient air at cathode side. This cell shows high performance with strong resistances against both coking and sulfur poisoning in dry fuel without any steam as reforming agent. At 800 °C, the cell exhibits a low polarization resistance of 0.027 Ω cm2 in air and 0.074 Ω cm2 in 5% H2. When the cell is further optimized by implementing a nanostructured electrode, the high peak power densities of 1.05 W cm−2 in H2 and 0.4 W cm−2 in CH4 are achieved at 800 °C. To our best knowledge, this is the highest performance among SSOFCs using ceramic oxide as symmetric electrode in dry methane. The cell exhibits a very stable performance under a constant current load of 1.0 A cm−2 for 1060 h with even slight performance increase. In addition, the electrode is structurally stable in various fuels, suggesting that the cell can be operated in flexible gas conditions.