Geochemical Characterization of the NWA 11273 Lunar Meteorite Using Nondestructive Analytical Techniques: Original, Shocked, and Alteration Mineral Phases

A lunar feldspathic breccia meteorite, the Northwest Africa (NWA) 11273, was analyzed to compensate the lack of scientific data available about its mineralogy and geochemistry. In order to obtain a deeper characterization of the sample, a strategy based on the combination of nondestructive spectroscopic techniques such as X-ray fluorescence and Raman spectroscopy is used. Both techniques are being used in spatial missions by the Perseverance Rover, so their combination in the laboratory is here proposed as an optimal strategy to study the complete mineralogy of the sample. In addition to finding the minerals indicated by the Meteoritical Society (anorthite, olivine, pyroxene, kamacite, and troilite), other minor minerals were identified, such as zircon and ilmenite, which are minerals related to the Moon geology, as well as calcite and sulfate which can be considered products of terrestrial weathering. Finally, secondary minerals related to alteration processes were also found, such as hematite, quartz, and anatase. In this work, the alteration processes that gave rise to the detected secondary minerals have been proposed.

Enhanced Li-ion transport in divalent metal-doped Li2SnO3

The improvement of Li-ion transport properties and doping engineering in Li-ion batteries are currently active research topics in the search for next-generation energy storage devices. In this theoretical work, the intrinsic defect formation and transport properties of divalent metal-doped Li2SnO3, which is being considered as an electrode and coating electrode material, are explored using atomistic simulations. Defect formation simulations reveal that all divalent dopants (Zn, Sc, Cd and Eu) occupy the Li site with charge compensation through Li vacancies. Molecular dynamics simulations show that the divalent dopants significantly reduce the activation energy for ionic diffusion and conduction compared to the undoped sample. The effects of both grains and grain boundaries on the Li-ion transport properties are investigated. Our calculated results demonstrate a marked improvement in the properties of Li2SnO3 that can be achieved either in current commercial and next-generation Li-ion battery technologies through divalent doping in mono- and polycrystalline Li2SnO3 samples.