Search NASA⌕ Search

DOE OSTI · 1750039

Materials Data on Er6Al41Cr6 by Materials Project

Abstract

Er6Cr6Al41 crystallizes in the trigonal P-31m space group. The structure is three-dimensional. there are two inequivalent Er sites. In the first Er site, Er is bonded in a 6-coordinate geometry to one Er, one Cr, and fifteen Al atoms. The Er–Er bond length is 3.48 Å. The Er–Cr bond length is 3.45 Å. There are a spread of Er–Al bond distances ranging from 3.05–3.40 Å. In the second Er site, Er is bonded in a 6-coordinate geometry to one Er, three Cr, and thirteen Al atoms. The Er–Er bond length is 3.42 Å. There are two shorter (3.23 Å) and one longer (3.49 Å) Er–Cr bond lengths. There are a spread of Er–Al bond distances ranging from 2.99–3.38 Å. There are four inequivalent Cr sites. In the first Cr site, Cr is bonded in a 10-coordinate geometry to two Er and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.47–2.71 Å. In the second Cr site, Cr is bonded to three equivalent Er and nine Al atoms to form distorted CrEr3Al9 cuboctahedra that share corners with three equivalent CrEr3Al9 cuboctahedra, edges with three equivalent AlEr2Al9Cr cuboctahedra, a faceface with one CrEr3Al9 cuboctahedra, and faces with four AlEr2Al9Cr cuboctahedra. There are a spread of Cr–Al bond distances ranging from 2.58–2.79 Å. In the third Cr site, Cr is bonded in a cuboctahedral geometry to twelve Al atoms. There are six shorter (2.62 Å) and six longer (2.78 Å) Cr–Al bond lengths. In the fourth Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share faces with six equivalent AlEr2Al9Cr cuboctahedra. There are six shorter (2.63 Å) and six longer (2.77 Å) Cr–Al bond lengths. There are eleven inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to four equivalent Er and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.71–3.05 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Er, two Cr, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.66–3.10 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to four equivalent Er, two equivalent Cr, and six Al atoms. There are two shorter (2.65 Å) and two longer (2.78 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded to two equivalent Er, one Cr, and nine Al atoms to form distorted AlEr2Al9Cr cuboctahedra that share a cornercorner with one AlEr2Al9Cr cuboctahedra, an edgeedge with one AlEr2Al9Cr cuboctahedra, edges with two equivalent CrEr3Al9 cuboctahedra, faces with three CrEr3Al9 cuboctahedra, and faces with four equivalent AlEr2Al9Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.72–2.90 Å. In the fifth Al site, Al is bonded in a 12-coordinate geometry to one Er, two Cr, and nine Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.91 Å. In the sixth Al site, Al is bonded in a 2-coordinate geometry to two equivalent Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.76–2.84 Å. In the seventh Al site, Al is bonded in a 12-coordinate geometry to two equivalent Er, one Cr, and nine Al atoms. There are two shorter (2.85 Å) and two longer (2.93 Å) Al–Al bond lengths. In the eighth Al site, Al is bonded in a 12-coordinate geometry to one Er, two Cr, and nine Al atoms. Both Al–Al bond lengths are 2.91 Å. In the ninth Al site, Al is bonded in a 12-coordinate geometry to two Er, two Cr, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.74–3.03 Å. In the tenth Al site, Al is bonded in a 12-coordinate geometry to two equivalent Er, one Cr, and nine Al atoms. There are one shorter (2.69 Å) and one longer (2.99 Å) Al–Al bond lengths. In the eleventh Al site, Al is bonded to three equivalent Er and nine Al atoms to form AlEr3Al9 cuboctahedra that share corners with three equivalent AlEr3Al9 cuboctahedra, a faceface with one CrEr3Al9 cuboctahedra, and a faceface with one AlEr3Al9 cuboctahedra.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-06-05. Materials Data on Er6Al41Cr6 by Materials Project. https://doi.org/10.17188/1750039

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↗