Insights on the Electrochemical Performance of a Molten Proton Conductor Fuel Cell with Internal Methanol Reformer

A fuel cell based on a molten proton conductor electrolyte membrane, in which polybenzimidazole (PBI) membrane is doped with molten CsH5(PO4)2, has been integrated in a single cell arrangement with a CuZn-based methanol reformer. It is demonstrated that the fuel cell with the internal reformer can efficiently operate at 220 °C, which is higher temperature than the upper limit of previously reported high-temperature proton exchange membrane fuel cell with an H3PO4-doped PBI membrane. Furthermore, the fuel cell with the internal reformer is able to provide 0.7 V at 200 mA cm−2 at 220 °C, keeping an open circuit voltage above 1 V, similarly with that under hydrogen feed at the same temperature. Electrochemical characterization of anode electrode surface area, also employing cyclic voltametry and impedance spectroscopy suggests that a performance decay after a transient operation with several on-off cycles, is due to proton conductor loss in the electrode's catalyst layer of the single cell.