Search NASA⌕ Search

DOE OSTI · 1263219

Materials Data on Li15Cr2N9 by Materials Project

Abstract

Li15Cr2N9 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are fifteen inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four N3- atoms to form LiN4 tetrahedra that share corners with four CrN4 tetrahedra, corners with six LiN4 tetrahedra, and edges with six LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 2.07–2.17 Å. In the second Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Li–N bond distances ranging from 2.01–2.36 Å. In the third Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Li–N bond distances ranging from 1.99–2.35 Å. In the fourth Li1+ site, Li1+ is bonded in a 3-coordinate geometry to four N3- atoms. There are a spread of Li–N bond distances ranging from 1.99–2.49 Å. In the fifth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Li–N bond distances ranging from 1.98–2.46 Å. In the sixth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with two equivalent CrN4 tetrahedra, corners with eleven LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with two LiN4 tetrahedra. There are two shorter (2.15 Å) and two longer (2.16 Å) Li–N bond lengths. In the seventh Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with two CrN4 tetrahedra, corners with ten LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with three LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 1.98–2.22 Å. In the eighth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with two CrN4 tetrahedra, corners with twelve LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with two LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 2.14–2.22 Å. In the ninth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with two equivalent CrN4 tetrahedra, corners with eleven LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with three LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 1.98–2.25 Å. In the tenth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share a cornercorner with one CrN4 tetrahedra, corners with ten LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with two LiN4 tetrahedra. There are three shorter (2.07 Å) and one longer (2.29 Å) Li–N bond lengths. In the eleventh Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share a cornercorner with one CrN4 tetrahedra, corners with ten LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with three LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 2.01–2.21 Å. In the twelfth Li1+ site, Li1+ is bonded to four N3- atoms to form LiN4 tetrahedra that share a cornercorner with one CrN4 tetrahedra, corners with nine LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with two LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 2.04–2.15 Å. In the thirteenth Li1+ site, Li1+ is bonded to four N3- atoms to form LiN4 tetrahedra that share a cornercorner with one CrN4 tetrahedra, corners with nine LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with three LiN4 tetrahedra. There are a spread of Li–N bond distances ranging from 2.02–2.12 Å. In the fourteenth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with twelve LiN4 tetrahedra, edges with two CrN4 tetrahedra, and edges with three LiN4 tetrahedra. There are two shorter (2.00 Å) and two longer (2.13 Å) Li–N bond lengths. In the fifteenth Li1+ site, Li1+ is bonded to four N3- atoms to form distorted LiN4 tetrahedra that share corners with two CrN4 tetrahedra, corners with eight LiN4 tetrahedra, an edgeedge with one CrN4 tetrahedra, and edges with five LiN4 tetrahedra. There are three shorter (2.12 Å) and one longer (2.13 Å) Li–N bond lengths. There are two inequivalent Cr6+ sites. In the first Cr6+ site, Cr6+ is bonded to four N3- atoms to form CrN4 tetrahedra that share corners with nine LiN4 tetrahedra and edges with five LiN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.75–1.80 Å. In the second Cr6+ site, Cr6+ is bonded to four N3- atoms to form CrN4 tetrahedra that share corners with nine LiN4 tetrahedra and edges with six LiN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.76–1.80 Å. There are nine inequivalent N3- sites. In the first N3- site, N3- is bonded in a body-centered cubic geometry to eight Li1+ atoms. In the second N3- site, N3- is bonded in a 7-coordinate geometry to six Li1+ and one Cr6+ atom. In the third N3- site, N3- is bonded in a distorted body-centered cubic geometry to seven Li1+ and one Cr6+ atom. In the fourth N3- site, N3- is bonded in a distorted body-centered cubic geometry to seven Li1+ and one Cr6+ atom. In the fifth N3- site, N3- is bonded in a 7-coordinate geometry to six Li1+ and one Cr6+ atom. In the sixth N3- site, N3- is bonded in a 7-coordinate geometry to six Li1+ and one Cr6+ atom. In the seventh N3- site, N3- is bonded in a 7-coordinate geometry to six Li1+ and one Cr6+ atom. In the eighth N3- site, N3- is bonded in a 8-coordinate geometry to seven Li1+ and one Cr6+ atom. In the ninth N3- site, N3- is bonded in a 8-coordinate geometry to seven Li1+ and one Cr6+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on Li15Cr2N9 by Materials Project. https://doi.org/10.17188/1263219

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↗