Search NASA⌕ Search

DOE OSTI · 1705284

Materials Data on Rb4Al2S5 by Materials Project

Abstract

Rb4Al2S5 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are four inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Rb–S bond distances ranging from 3.31–3.66 Å. In the second Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Rb–S bond distances ranging from 3.30–3.80 Å. In the third Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Rb–S bond distances ranging from 3.35–3.67 Å. In the fourth Rb1+ site, Rb1+ is bonded to six S2- atoms to form distorted RbS6 pentagonal pyramids that share corners with two equivalent RbS6 pentagonal pyramids, corners with five AlS4 tetrahedra, and edges with two AlS4 tetrahedra. There are a spread of Rb–S bond distances ranging from 3.20–3.41 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four S2- atoms to form AlS4 tetrahedra that share corners with three equivalent RbS6 pentagonal pyramids, a cornercorner with one AlS4 tetrahedra, an edgeedge with one RbS6 pentagonal pyramid, and an edgeedge with one AlS4 tetrahedra. There are a spread of Al–S bond distances ranging from 2.23–2.34 Å. In the second Al3+ site, Al3+ is bonded to four S2- atoms to form AlS4 tetrahedra that share corners with two equivalent RbS6 pentagonal pyramids, a cornercorner with one AlS4 tetrahedra, an edgeedge with one RbS6 pentagonal pyramid, and an edgeedge with one AlS4 tetrahedra. There are a spread of Al–S bond distances ranging from 2.23–2.32 Å. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to four Rb1+ and two Al3+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to six Rb1+ and one Al3+ atom. In the third S2- site, S2- is bonded in a 2-coordinate geometry to four Rb1+ and two Al3+ atoms. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to six Rb1+ and one Al3+ atom. In the fifth S2- site, S2- is bonded in a 6-coordinate geometry to four Rb1+ and two Al3+ atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-01. Materials Data on Rb4Al2S5 by Materials Project. https://doi.org/10.17188/1705284

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

Cyclic moisture reactivation of calcium sorbents for long duration thermochemical energy storage

The transition to a flexible and reliable energy infrastructure, using electro-thermal energy generation technologies such as geothermal, concentrated solar power, and nuclear, usually demands simultaneous advancement of thermal energy storage (TES) to support on-demand electricity generation and industrial applications while mitigating the inherent intermittency of renewable energy sources and power outages from direct energy generation. Among TES technologies, thermochemical energy storage (TCES) based on calcium looping emerges as a compelling high-power energy storage candidate due to its high reaction enthalpy, compatibility with elevated operating temperatures, and abundance of low-cost materials. However, the long-term durability of calcium-based sorbents for TCES is hindered by surface sintering and particle aggregation, leading to performance degradation over repeated thermal cycles. This study explores a moisture hydration-based strategy to regenerate a degraded calcium sorbent and mitigate performance degradation for long duration TCES. The addition of moisture transforms calcium oxide into calcium hydroxide and produces intercalation water layers, associated with a regenerated surface area and reduced calcium oxide crystallite size. Both these effects are beneficial in restoring the sorbents' reactivity for carbonization. Additionally, an optimized hydration-assisted reactivation protocol balances the recovered energy storage capacity with heating penalty required for moisture removal from hydrated samples, resulting in an enhanced energy storage capacity up to 176% compared to benchmark sorbents that undergo cycling without reactivation after 60 cycles. In conclusion, these results highlight the potential of hydration-assisted reactivation to enhance the long-term performance of TCES, providing an effective pathway to advancing electro-thermal storage technologies.

36 MATERIALS SCIENCE↗