Search NASA⌕ Search

DOE OSTI · 1683615

Materials Data on Yb7Mg3Si8 by Materials Project

Abstract

Mg3Yb7Si8 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 4-coordinate geometry to five Si3- atoms. There are a spread of Mg–Si bond distances ranging from 2.83–3.25 Å. In the second Mg2+ site, Mg2+ is bonded in a T-shaped geometry to three Si3- atoms. There are a spread of Mg–Si bond distances ranging from 2.77–2.82 Å. In the third Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six Si3- atoms. There are a spread of Mg–Si bond distances ranging from 2.79–3.08 Å. There are seven inequivalent Yb+2.57+ sites. In the first Yb+2.57+ site, Yb+2.57+ is bonded to seven Si3- atoms to form distorted corner-sharing YbSi7 pentagonal bipyramids. There are a spread of Yb–Si bond distances ranging from 3.07–3.38 Å. In the second Yb+2.57+ site, Yb+2.57+ is bonded to seven Si3- atoms to form distorted corner-sharing YbSi7 pentagonal bipyramids. There are a spread of Yb–Si bond distances ranging from 3.07–3.34 Å. In the third Yb+2.57+ site, Yb+2.57+ is bonded in a 7-coordinate geometry to seven Si3- atoms. There are a spread of Yb–Si bond distances ranging from 2.95–3.45 Å. In the fourth Yb+2.57+ site, Yb+2.57+ is bonded in a 6-coordinate geometry to six Si3- atoms. There are a spread of Yb–Si bond distances ranging from 3.01–3.15 Å. In the fifth Yb+2.57+ site, Yb+2.57+ is bonded in a 6-coordinate geometry to six Si3- atoms. There are a spread of Yb–Si bond distances ranging from 2.93–3.08 Å. In the sixth Yb+2.57+ site, Yb+2.57+ is bonded in a 6-coordinate geometry to six Si3- atoms. There are a spread of Yb–Si bond distances ranging from 2.98–3.08 Å. In the seventh Yb+2.57+ site, Yb+2.57+ is bonded in a 6-coordinate geometry to six Si3- atoms. There are a spread of Yb–Si bond distances ranging from 2.88–3.04 Å. There are eight inequivalent Si3- sites. In the first Si3- site, Si3- is bonded in a 9-coordinate geometry to three Mg2+, five Yb+2.57+, and one Si3- atom. The Si–Si bond length is 2.36 Å. In the second Si3- site, Si3- is bonded in a 9-coordinate geometry to two equivalent Mg2+, six Yb+2.57+, and one Si3- atom. The Si–Si bond length is 2.39 Å. In the third Si3- site, Si3- is bonded in a 8-coordinate geometry to three Mg2+, four Yb+2.57+, and one Si3- atom. In the fourth Si3- site, Si3- is bonded in a 8-coordinate geometry to one Mg2+, six Yb+2.57+, and one Si3- atom. In the fifth Si3- site, Si3- is bonded in a 9-coordinate geometry to two Mg2+, six Yb+2.57+, and one Si3- atom. The Si–Si bond length is 2.41 Å. In the sixth Si3- site, Si3- is bonded in a 8-coordinate geometry to one Mg2+, six Yb+2.57+, and one Si3- atom. The Si–Si bond length is 2.33 Å. In the seventh Si3- site, Si3- is bonded in a 8-coordinate geometry to seven Yb+2.57+ and one Si3- atom. In the eighth Si3- site, Si3- is bonded in a 8-coordinate geometry to two Mg2+, five Yb+2.57+, and one Si3- atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on Yb7Mg3Si8 by Materials Project. https://doi.org/10.17188/1683615

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↗