Search NASA⌕ Search

DOE OSTI · 1759651

Materials Data on Li7PSe6 by Materials Project

Abstract

Li7PSe6 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are seven inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four Se2- atoms to form LiSe4 tetrahedra that share corners with two equivalent PSe4 tetrahedra, corners with six LiSe4 tetrahedra, a cornercorner with one LiSe4 trigonal pyramid, an edgeedge with one LiSe4 tetrahedra, and an edgeedge with one LiSe4 trigonal pyramid. There are a spread of Li–Se bond distances ranging from 2.56–2.74 Å. In the second Li1+ site, Li1+ is bonded to four Se2- atoms to form LiSe4 tetrahedra that share corners with two LiSe4 tetrahedra, corners with two equivalent PSe4 tetrahedra, corners with three equivalent LiSe4 trigonal pyramids, and edges with three LiSe4 tetrahedra. There are a spread of Li–Se bond distances ranging from 2.55–2.71 Å. In the third Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are a spread of Li–Se bond distances ranging from 2.62–2.89 Å. In the fourth Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five Se2- atoms. There are a spread of Li–Se bond distances ranging from 2.55–3.29 Å. In the fifth Li1+ site, Li1+ is bonded to four Se2- atoms to form LiSe4 tetrahedra that share corners with two equivalent PSe4 tetrahedra, corners with four LiSe4 tetrahedra, corners with three equivalent LiSe4 trigonal pyramids, and edges with two LiSe4 tetrahedra. There are a spread of Li–Se bond distances ranging from 2.58–2.65 Å. In the sixth Li1+ site, Li1+ is bonded to four Se2- atoms to form LiSe4 trigonal pyramids that share corners with two equivalent PSe4 tetrahedra, corners with eight LiSe4 tetrahedra, and edges with two LiSe4 tetrahedra. There are a spread of Li–Se bond distances ranging from 2.56–2.73 Å. In the seventh Li1+ site, Li1+ is bonded to four Se2- atoms to form LiSe4 tetrahedra that share corners with two equivalent PSe4 tetrahedra, corners with four LiSe4 tetrahedra, a cornercorner with one LiSe4 trigonal pyramid, edges with two LiSe4 tetrahedra, and an edgeedge with one LiSe4 trigonal pyramid. There are a spread of Li–Se bond distances ranging from 2.57–2.64 Å. P5+ is bonded to four Se2- atoms to form PSe4 tetrahedra that share corners with eight LiSe4 tetrahedra and corners with two equivalent LiSe4 trigonal pyramids. There are two shorter (2.22 Å) and two longer (2.23 Å) P–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to seven Li1+ atoms to form distorted SeLi7 pentagonal bipyramids that share corners with two equivalent SeLi7 pentagonal bipyramids, corners with three equivalent SeLi3P tetrahedra, an edgeedge with one SeLi7 pentagonal bipyramid, and a faceface with one SeLi7 pentagonal bipyramid. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to four Li1+ and one P5+ atom. In the third Se2- site, Se2- is bonded to seven Li1+ atoms to form distorted SeLi7 pentagonal bipyramids that share corners with two equivalent SeLi7 pentagonal bipyramids, corners with three equivalent SeLi3P tetrahedra, an edgeedge with one SeLi7 pentagonal bipyramid, and a faceface with one SeLi7 pentagonal bipyramid. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Li1+ and one P5+ atom. In the fifth Se2- site, Se2- is bonded to three Li1+ and one P5+ atom to form corner-sharing SeLi3P tetrahedra. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Li1+ and one P5+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-09-03. Materials Data on Li7PSe6 by Materials Project. https://doi.org/10.17188/1759651

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↗