Search NASA⌕ Search

DOE OSTI · 1269404

Materials Data on Na2Zr(CuS2)2 by Materials Project

Abstract

Na2Cu2ZrS4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Na1+ is bonded to seven S2- atoms to form distorted NaS7 pentagonal bipyramids that share corners with six equivalent ZrS6 octahedra, corners with seven equivalent CuS4 tetrahedra, an edgeedge with one ZrS6 octahedra, edges with four equivalent NaS7 pentagonal bipyramids, edges with three equivalent CuS4 tetrahedra, a faceface with one ZrS6 octahedra, and faces with three equivalent NaS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 28–43°. There are a spread of Na–S bond distances ranging from 2.87–3.21 Å. Zr4+ is bonded to six S2- atoms to form ZrS6 octahedra that share corners with twelve equivalent NaS7 pentagonal bipyramids, corners with two equivalent CuS4 tetrahedra, edges with two equivalent ZrS6 octahedra, edges with two equivalent NaS7 pentagonal bipyramids, edges with four equivalent CuS4 tetrahedra, and faces with two equivalent NaS7 pentagonal bipyramids. There are four shorter (2.61 Å) and two longer (2.62 Å) Zr–S bond lengths. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one ZrS6 octahedra, corners with seven equivalent NaS7 pentagonal bipyramids, corners with two equivalent CuS4 tetrahedra, edges with two equivalent ZrS6 octahedra, edges with three equivalent NaS7 pentagonal bipyramids, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. There are a spread of Cu–S bond distances ranging from 2.29–2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 7-coordinate geometry to three equivalent Na1+, one Zr4+, and three equivalent Cu1+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to four equivalent Na1+, two equivalent Zr4+, and one Cu1+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-07-16. Materials Data on Na2Zr(CuS2)2 by Materials Project. https://doi.org/10.17188/1269404

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↗