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6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

A Progress Report on Metal–Sulfur Batteries

Nonaqueous conversion-reaction sulfur chemistry has been attracting increasing attention over the past decade for the development of next-generation lithium-based batteries. Li–S batteries are currently approaching a nexus stage from lab-scale experiments to possible pragmatic applications. Inspired by the success of Li–S chemistry, other metal–sulfur batteries with a variety of metallic anodes, such as sodium, potassium, magnesium, calcium, and aluminum, have also started to attract attention. In comparison to lithium, Na, Mg, Al, K, and Ca are naturally more abundant and affordable. The Na-S, Mg-S, Al-S, K-S, and Ca-S battery systems provide a great potential for improving the volumetric energy density of sulfur-based batteries. The multivalent metal-sulfur systems, Mg-S, Al-S, and Ca-S, offer better safety features as well. However, the research and development on Na-S, Mg-S, Al-S, K-S, and Ca-S batteries is far behind the Li–S system due to many critical challenges. In this progress report, the fundamental principles of various metal–sulfur chemistries are first presented and compared. Then, the historical progress, recent advances, and key challenges of the Li–S, Na-S, Mg-S, Al-S, K-S, and Ca-S systems are summarized and discussed. Finally, future efforts and directions for both the fundamental and practical research are prospected.

25 ENERGY STORAGE↗
NASA NTRS2022

X-Ray Amorphous Sulfur-Bearing Phases in Sedimentary Rocks of Gale Crater, Mars

The Curiosity rover in Gale crater is investigating a mineral transition observed from orbit—an older “clay unit” to a younger “sulfate unit”—hypothesized to reflect the aridification of Mars' climate. Below this transition, the rover detected crystalline Ca-sulfates with minor Fe-sulfates but also found that some fraction of a rock's bulk SO 3 is often in the poorly constrained X-ray amorphous component. Here, we characterize the abundances and compositions of the X-ray amorphous sulfur-bearing phases in 19 drilled samples using a mass balance approach, and in a subset of 5 samples using evolved SO 2 gas measured using the SAM instrument. We find that ∼20–90 wt% of a sample's bulk SO 3 is in the X-ray amorphous state and that X-ray amorphous sulfur-bearing phase compositions are consistent with mixtures of Mg-S, Fe-S, and possibly Ca-S phases, likely sulfates or sulfites. These phases reside in the bedrock, perhaps as cementing agents deposited with detrital sediments or during early diagenesis, and in diagenetic alteration halos deposited after lithification during late diagenesis. The likely presence of highly soluble Mg-sulfates in the rocks suggests negligible fluid flow through the bedrock post-Mg-sulfate deposition. The X-ray amorphous sulfur-bearing phases probably became amorphous through dehydration in the current Martian atmosphere or inside the CheMin instrument. X-ray amorphous sulfur-bearing materials likely contribute to orbital spectral detections of sulfates, and so our results help form multiple hypotheses to be tested in the sulfate unit and are important for understanding the evolution of the Martian surface environment at Gale crater.

R. J. Smith↗
DOE OSTI2020

Materials Data on MgS by Materials Project

MgS is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent S2- atoms to form corner-sharing MgS4 tetrahedra. All Mg–S bond lengths are 2.47 Å. S2- is bonded to four equivalent Mg2+ atoms to form corner-sharing SMg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgS by Materials Project

MgS is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent S2- atoms to form a mixture of edge and corner-sharing MgS6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–S bond lengths are 2.61 Å. S2- is bonded to six equivalent Mg2+ atoms to form a mixture of edge and corner-sharing SMg6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgS3 by Materials Project

MgS3 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Mg2+ is bonded to six S+0.67- atoms to form a mixture of edge and corner-sharing MgS6 octahedra. The corner-sharing octahedra tilt angles range from 0–32°. There are a spread of Mg–S bond distances ranging from 2.62–2.76 Å. There are three inequivalent S+0.67- sites. In the first S+0.67- site, S+0.67- is bonded in a distorted see-saw-like geometry to four S+0.67- atoms. There are two shorter (2.24 Å) and two longer (2.53 Å) S–S bond lengths. In the second S+0.67- site, S+0.67- is bonded in a 2-coordinate geometry to two equivalent Mg2+ and two equivalent S+0.67- atoms. In the third S+0.67- site, S+0.67- is bonded to four equivalent Mg2+ and two equivalent S+0.67- atoms to form a mixture of distorted edge and corner-sharing SMg4S2 octahedra. The corner-sharing octahedra tilt angles range from 0–11°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgS2 by Materials Project

MgS2 is Marcasite-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent S1- atoms to form edge-sharing MgS6 octahedra. All Mg–S bond lengths are 2.61 Å. S1- is bonded in a 4-coordinate geometry to three equivalent Mg2+ and one S1- atom. The S–S bond length is 2.10 Å.

36 MATERIALS SCIENCE↗