Enhancement of Oxygen Transport in the Storage Electrode of a High Temperature Secondary Metal-Air Battery Based on an Oxygen Ion Conducting Electrolyte

Abstract

The concept of a new reversible metal air battery with high cycling capability is based on a porous structure of iron-iron oxide serving as storage of low oxygen activity which is coupled to the negative electrode of a solid oxide fuel / electrolyzer cell via gas diffusion in stagnant atmosphere of a gaseous redox couple. The positive electrode is supplied by air. Such concept does not suffer from the problem of degrading contacts in the storage electrodes caused by volume change of solid phases upon charge and discharge. Basic quantitative reasoning shows that as gaseous redox couple a mixture of hydrogen and water vapor is ideally suited to achieve high performance. Experimental results are presented, which demonstrate the low overall polarization of this kind of storage concept.