Challenges of Solid Oxide Electrolysis for Production of Fuel and Oxygen from Mars Atmospheric CO2

Abstract

Due to the potential for unmatched efficiency, solid oxide electrolysis has long been considered a leading technology for enabling the hydrogen economy. More recently, the potential of co-electrolysis to “fix” intermittent renewable energy by recycling CO2 to storable, transportable liquid transportation fuels has demonstrated substantial progress. A new field of application for solid oxide electrolysis producing fuels from CO2 is emerging in the area of human exploration of Mars. The Martian atmosphere is 96% CO2, making it a prime resource for extraction of oxygen that will be needed by human explorers and for production of the fuel that will be needed for the ascent vehicle to return them to earth. There are innumerable logistical and programmatic challenges to designing, qualifying, delivering and operating any process for insitu resource utilization (ISRU) on the surface of such a remote and inhospitable place such as Mars. This paper makes no attempt to address any beyond the design of the solid oxide electrolysis device itself. Ceramatec has been active in solid oxide fuel cell R&D for nearly three decades, and solid oxide electrolysis for the later half of that period. The fundamental operating principles and materials of the Mars ISRU application are no different than the hydrogen and synfuel applications of past decades. However there are circumstances of the ISRU application that place challenging constraints on the design and performance that have not been previously encountered in our SOEC development efforts. These issues are outlined and the design, analysis, materials and operational approaches to address them are presented. Ceramatec is designing and building the SOEC (aka SOXE) stack for the MOXIE instrument on the Mars 2020 mission.