Search NASA⌕ Search

DOE OSTI · 1268420

Materials Data on KNa4SnSb3 by Materials Project

Abstract

KNa4SnSb3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded to five Sb3- atoms to form distorted KSb5 trigonal bipyramids that share corners with two equivalent SnSb4 tetrahedra, corners with six NaSb4 tetrahedra, corners with two equivalent KSb5 trigonal bipyramids, corners with three equivalent NaSb4 trigonal pyramids, edges with two equivalent SnSb4 tetrahedra, edges with four NaSb4 tetrahedra, an edgeedge with one KSb5 trigonal bipyramid, and edges with two equivalent NaSb4 trigonal pyramids. There are a spread of K–Sb bond distances ranging from 3.49–3.72 Å. There are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted see-saw-like geometry to four Sb3- atoms. There are a spread of Na–Sb bond distances ranging from 3.20–3.55 Å. In the second Na1+ site, Na1+ is bonded to four Sb3- atoms to form NaSb4 tetrahedra that share corners with three equivalent SnSb4 tetrahedra, corners with five NaSb4 tetrahedra, corners with three equivalent KSb5 trigonal bipyramids, corners with two equivalent NaSb4 trigonal pyramids, an edgeedge with one NaSb4 tetrahedra, an edgeedge with one SnSb4 tetrahedra, edges with two equivalent KSb5 trigonal bipyramids, and edges with two equivalent NaSb4 trigonal pyramids. There are a spread of Na–Sb bond distances ranging from 3.15–3.26 Å. In the third Na1+ site, Na1+ is bonded to four Sb3- atoms to form NaSb4 tetrahedra that share corners with three equivalent NaSb4 tetrahedra, corners with five equivalent SnSb4 tetrahedra, corners with three equivalent KSb5 trigonal bipyramids, corners with three equivalent NaSb4 trigonal pyramids, edges with two NaSb4 tetrahedra, edges with two equivalent KSb5 trigonal bipyramids, and an edgeedge with one NaSb4 trigonal pyramid. There are a spread of Na–Sb bond distances ranging from 3.19–3.30 Å. In the fourth Na1+ site, Na1+ is bonded to four Sb3- atoms to form distorted NaSb4 trigonal pyramids that share corners with three equivalent SnSb4 tetrahedra, corners with five NaSb4 tetrahedra, corners with three equivalent KSb5 trigonal bipyramids, corners with two equivalent NaSb4 trigonal pyramids, an edgeedge with one SnSb4 tetrahedra, edges with three NaSb4 tetrahedra, and edges with two equivalent KSb5 trigonal bipyramids. There are a spread of Na–Sb bond distances ranging from 3.28–3.68 Å. Sn4+ is bonded to four Sb3- atoms to form SnSb4 tetrahedra that share corners with eight NaSb4 tetrahedra, corners with two equivalent KSb5 trigonal bipyramids, corners with three equivalent NaSb4 trigonal pyramids, an edgeedge with one NaSb4 tetrahedra, an edgeedge with one SnSb4 tetrahedra, edges with two equivalent KSb5 trigonal bipyramids, and an edgeedge with one NaSb4 trigonal pyramid. There are a spread of Sn–Sb bond distances ranging from 2.85–2.96 Å. There are three inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a 7-coordinate geometry to one K1+, four Na1+, and two equivalent Sn4+ atoms. In the second Sb3- site, Sb3- is bonded in a 9-coordinate geometry to two equivalent K1+, six Na1+, and one Sn4+ atom. In the third Sb3- site, Sb3- is bonded in a 9-coordinate geometry to two equivalent K1+, six Na1+, and one Sn4+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-29. Materials Data on KNa4SnSb3 by Materials Project. https://doi.org/10.17188/1268420

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↗