(Invited) Zirconia-Based Hollow Anode Development for Molten Regolith Electrolysis

Abstract

Molten regolith electrolysis (MRE) is a promising in-situ resource utilization technique for producing oxygen and molten metal alloys from lunar regolith. However, MRE requires operating temperatures at or above 1600°C to melt lunar regolith and dissociate the molten oxides to enable electrolysis. Anode degradation in this corrosive and oxidizing environment is a major concern for long-term operation on the lunar surface and can be mitigated by a novel hollow anode design with a solid electrolyte shell and porous metallic core as proposed here. The metallic anode will be shielded from the regolith melt by an oxygen ion-conducting zirconia-based ceramic, allowing electron transfer to occur in the interior of the shell. Additionally, bubble formation at a traditional anode surface is avoided, thereby eliminating the concerns of molten regolith splatter and increased ohmic resistance. This work focuses on corrosion studies of dense stabilized zirconia in contact with molten lunar mare and highlands regolith simulants at 1600°C to support hollow anode development. The interactions between zirconia and molten regolith are characterized using SEM/EDS, with an emphasis on elemental analysis to assess reactivity and degradation of zirconia.