Search NASA⌕ Search

DOE OSTI · 1712318

Materials Data on CeMg14Si by Materials Project

Abstract

Mg14CeSi crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are six inequivalent Mg sites. In the first Mg site, Mg is bonded to ten Mg and two equivalent Ce atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent SiMg12 cuboctahedra, corners with fourteen MgCe2Mg10 cuboctahedra, edges with two equivalent CeMg12 cuboctahedra, edges with sixteen MgCe2Mg10 cuboctahedra, faces with two equivalent CeMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.11–3.26 Å. Both Mg–Ce bond lengths are 3.18 Å. In the second Mg site, Mg is bonded to ten Mg and two equivalent Si atoms to form distorted MgMg10Si2 cuboctahedra that share corners with four equivalent CeMg12 cuboctahedra, corners with fourteen MgCe2Mg10 cuboctahedra, edges with two equivalent SiMg12 cuboctahedra, edges with sixteen MgMg10Si2 cuboctahedra, faces with two equivalent SiMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.14–3.23 Å. Both Mg–Si bond lengths are 3.18 Å. In the third Mg site, Mg is bonded to ten Mg and two equivalent Ce atoms to form MgCe2Mg10 cuboctahedra that share corners with four equivalent SiMg12 cuboctahedra, corners with fourteen MgMg10Si2 cuboctahedra, edges with two equivalent CeMg12 cuboctahedra, edges with sixteen MgCe2Mg10 cuboctahedra, faces with two equivalent CeMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. There are two shorter (3.16 Å) and four longer (3.23 Å) Mg–Mg bond lengths. Both Mg–Ce bond lengths are 3.18 Å. In the fourth Mg site, Mg is bonded to ten Mg, one Ce, and one Si atom to form distorted MgCeMg10Si cuboctahedra that share corners with eighteen MgCeMg10Si cuboctahedra, edges with two equivalent CeMg12 cuboctahedra, edges with two equivalent SiMg12 cuboctahedra, edges with fourteen MgCe2Mg10 cuboctahedra, a faceface with one CeMg12 cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.15–3.22 Å. The Mg–Ce bond length is 3.23 Å. The Mg–Si bond length is 3.12 Å. In the fifth Mg site, Mg is bonded to ten Mg, one Ce, and one Si atom to form distorted MgCeMg10Si cuboctahedra that share corners with eighteen MgCeMg10Si cuboctahedra, edges with two equivalent CeMg12 cuboctahedra, edges with two equivalent SiMg12 cuboctahedra, edges with fourteen MgCe2Mg10 cuboctahedra, a faceface with one CeMg12 cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.15–3.22 Å. The Mg–Ce bond length is 3.23 Å. The Mg–Si bond length is 3.12 Å. In the sixth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgCeMg10Si cuboctahedra, edges with eighteen MgCe2Mg10 cuboctahedra, faces with three equivalent CeMg12 cuboctahedra, faces with three equivalent SiMg12 cuboctahedra, and faces with fourteen MgCe2Mg10 cuboctahedra. Ce is bonded to twelve Mg atoms to form CeMg12 cuboctahedra that share corners with six equivalent CeMg12 cuboctahedra, corners with twelve equivalent MgMg10Si2 cuboctahedra, edges with eighteen MgCe2Mg10 cuboctahedra, faces with two equivalent SiMg12 cuboctahedra, and faces with eighteen MgCe2Mg10 cuboctahedra. Si is bonded to twelve Mg atoms to form SiMg12 cuboctahedra that share corners with six equivalent SiMg12 cuboctahedra, corners with twelve MgCe2Mg10 cuboctahedra, edges with eighteen MgCeMg10Si cuboctahedra, faces with two equivalent CeMg12 cuboctahedra, and faces with eighteen MgMg10Si2 cuboctahedra.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on CeMg14Si by Materials Project. https://doi.org/10.17188/1712318

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↗