Ionic Liquid-Assisted Electrochemical Extraction of Oxygen from Lunar Regolith

Abstract

Among the numerous technological advances sought in order to facilitate human exploration and habitation outside of earth’s atmosphere, solutions and innovations are needed for processing local resources to support sustainable and long duration space missions. Such in-situ resource utilization (ISRU) is aimed at reducing the payload mass during launch and eliminate the need for ground support for long-term missions and ultimately space colonization. One particular need for habitation and deep space exploration is the continuous supply of oxygen for life support and for propellants in the form of liquid oxygen. As mission duration is extended, the availability of a consistent supply of oxygen will become critical. The entire lunar surface is covered by regolith which is approximately 45% oxygen by mass, making it a very large reservoir. However, this oxygen is in the form of metal and mineral oxides. NASA thus recognizes the need to develop approaches to utilize this oxygen and material resource.Faraday Technology Inc. and RoCo Global are addressing this unique challenge by demonstrating the feasibility of an efficient ionic liquid-assisted electrochemical system for oxygen recovery from SiO2 that can be employed on lunar surfaces for oxygen extraction from lunar regolith. Accordingly, Faraday and RoCo Global have successfully: 1) Developed a scalable bifluoride based IL with reduced process complexity that can enable direct solubilization of SiO2; 2) Developed an experimental approach utilizing an electrochemical Liquid-Liquid-Solid (LLS) process [i],[ii] [iii] [iv] for the extraction of oxygen and deposition of Si from the solubilized SiO2 in the bifluoride based IL; 3) Demonstrated feasibility to recover oxygen and electrodeposit Si from SiO2 solubilized in bifluoride based IL electrolyte; 4) Demonstrated feasibility of reutilizing IL electrolyte for multiple SiO2 solubilization cycles; 5) Prepared a preliminary semi-continuous alpha-scale design (Figure 1). Acknowledgements: Financial support of NASA Contract 80NSSC-20-C-0338 is acknowledged.