Sodium-Ion Cathodes Designed for in-Situ Resource Utilization on the Moon and Mars

On-demand in-space and on-surface manufacturing of batteries is sought to deliver energy storage devices needed for sustained human presence on the Moon and Mars. In-situ resource utilization (ISRU) is a disruptive approach that reduces the dependence on launch payload weight and volume to maximize long-term sustainability of exploration where resupply may be infeasible or costly. While lithium-ion batteries have seen widespread adoption in mobile devices and electric vehicles, the low abundance of lithium in lunar and martian regolith necessitates selection of an alternative chemistry for batteries derived from ISRU materials. Compared to lithium, sodium and the appropriate redox active cations for sodium-ion batteries are more abundant. However, state-of-the-art sodium-ion cathodes may be more complex in chemistry and use elements that are not feasible to attain by ISRU manufacturing. In this work, candidate sodium-ion cathodes were studied within the elemental abundance limitations on the Moon and Mars and in consideration of requirements for 3D printing and post-printing thermal treatment, such as stability of active material during resin curing and burnout. Cathode composition and processing conditions were varied to explore the balance between specific energy density and cycling performance with elemental abundance, specifically searching for replacement of manganese in layered and tunnel-type cathodes. This study found that a critical manganese content is required to stabilize the orthorhombic tunnel type structure with Pbam symmetry (Na 0.44 MnO 2 type), over the NaTiFeO 4 type Pnma symmetry, and that the stability was also a function of sodium content and calcination temperature.