Stability evaluation under cycling conditions of a fuel cell stack based on molten proton conductor electrolyte membranes and internal methanol reformers

Based on the concept of the internal reforming methanol fuel cell (IRMFC), a fuel cell stack with 4 membrane electrode assemblies (MEAs) integrated with 4 fuel processors has been developed, containing molten CsH 5 (PO 4 ) 2 doped polybenzimidazole (PBI) membranes and highly active and selective CuZnGaAlO x catalysts, respectively. This innovative fuel cell stack configuration can efficiently operate at 220 °C and depending on the feed stream, either pure hydrogen or reformate gas mixtures, power outputs up to 20 W can be obtained. Exceptional electrochemical performance and long-term stability of the fuel cell stack, even under transient conditions, has been demonstrated with a 500 h test including several runs at 220 °C and on-off cycles from room temperature up to the operation temperature at 220 °C. The superior mechanical and thermal stability of this generation of CsH 5 (PO 4 ) 2 -doped PBI membrane, together with highly efficient and stable copper-based methanol reforming catalyst, are combined in a compact and single power unit opening new prospects for next generation portable and off-grid energy applications. • Molten proton conductor fuel cell stack with internal methanol reformers. • CsH 5 (PO 4 ) 2 -doped PBI membranes able to support operation at 220 o C. • Highly efficient CuZnGaAlO x catalysts supporting MEAs operation at 220 o C. • Power output within the range of 10–20 W, keeping OCV per MEA above 1 V. • Superior thermal stability during harsh cycling conditions.