Search NASA⌕ Search

DOE OSTI · 1277186

Materials Data on Na5SiP3 by Materials Project

Abstract

Na5SiP3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are five inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to five P+0.33- atoms. There are a spread of Na–P bond distances ranging from 2.86–3.46 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to two equivalent Si4- and five P+0.33- atoms. There are one shorter (3.25 Å) and one longer (3.29 Å) Na–Si bond lengths. There are a spread of Na–P bond distances ranging from 2.98–3.40 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four P+0.33- atoms. There are a spread of Na–P bond distances ranging from 2.92–3.28 Å. In the fourth Na1+ site, Na1+ is bonded to four P+0.33- atoms to form NaP4 tetrahedra that share corners with three equivalent SiNa2P4 tetrahedra, corners with five NaP4 tetrahedra, an edgeedge with one NaP4 tetrahedra, and an edgeedge with one SiNa2P4 tetrahedra. There are a spread of Na–P bond distances ranging from 2.86–2.92 Å. In the fifth Na1+ site, Na1+ is bonded to four P+0.33- atoms to form NaP4 tetrahedra that share corners with three equivalent NaP4 tetrahedra, corners with five equivalent SiNa2P4 tetrahedra, and edges with two NaP4 tetrahedra. There are a spread of Na–P bond distances ranging from 2.91–3.05 Å. Si4- is bonded to two equivalent Na1+ and four P+0.33- atoms to form distorted SiNa2P4 tetrahedra that share corners with eight NaP4 tetrahedra, an edgeedge with one NaP4 tetrahedra, and a faceface with one SiNa2P4 tetrahedra. There are a spread of Si–P bond distances ranging from 2.27–2.35 Å. There are three inequivalent P+0.33- sites. In the first P+0.33- site, P+0.33- is bonded in a 9-coordinate geometry to seven Na1+ and two equivalent Si4- atoms. In the second P+0.33- site, P+0.33- is bonded in a 9-coordinate geometry to eight Na1+ and one Si4- atom. In the third P+0.33- site, P+0.33- is bonded in a 7-coordinate geometry to seven Na1+ and one Si4- atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Na5SiP3 by Materials Project. https://doi.org/10.17188/1277186

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↗