High performance of SnP2O7-based intermediate temperature fuel cells was obtained with a quaternary ammonium-biphosphate ion-pair coordinated polymer electrolyte.

Portions of this research were carried out at MIT under a contract with the National Aeronautics and Space Administration (NNH17CH01C) and at the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 80NM0018D0004. We thank Gavin Kohn for modeling the dust loading rate and capture fraction.

An experimental study has been completed to assess the performance of single solid-oxide electrolysis cells operating over a temperature range of 800 to 900°C. The experiments were performed over a range of steam inlet partial pressures (2.3–12.2 kPa), carrier gas flow rates (50–200 sccm), and current densities (−0.75–0.25A∕cm2) using single electrolyte-supported button cells of scandia-stabilized zirconia. Steam consumption rates associated with electrolysis were measured directly using inlet and outlet dew-point instrumentation. Cell operating potentials and cell current were varied using a programmable power supply and monitored continuously. Values of area-specific resistance and thermal efficiency are presented as a function of current density. Cell performance is shown to be continuous from the fuel-cell mode to the electrolysis mode of operation. The effects of steam starvation and thermal cycling on cell performance parameters are discussed.

Electrolysis of water produces high‐purity hydrogen directly, with no need for additional clean‐up process. Efficiency and cost of electrolysis are favorable with high‐temperature steam electrolyzers where a portion of the required energy can be supplied as thermal energy. With the similarity in requirements, much of the materials and designs aspects for the high‐temperature electrolyzers have been derived from solid oxide fuel cell development. Lanthanum gallate electrolyte‐based cells were evaluated in fuel cell and electrolysis modes of operation. A modified nickel anode is shown to lower the reactivity with the gallate.