Search NASA⌕ Search

DOE OSTI · 1318506

Materials Data on CaV4(CuO7)2 by Materials Project

Abstract

CaV4(CuO7)2 crystallizes in the monoclinic P2 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six VO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.50 Å. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.85 Å. There are six inequivalent V5+ sites. In the first V5+ site, V5+ is bonded to four O2- atoms to form corner-sharing VO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.68–1.81 Å. In the second V5+ site, V5+ is bonded to four O2- atoms to form corner-sharing VO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.67–1.80 Å. In the third V5+ site, V5+ is bonded to four O2- atoms to form corner-sharing VO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.66–1.84 Å. In the fourth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one CaO6 octahedra and a cornercorner with one VO4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of V–O bond distances ranging from 1.63–1.81 Å. In the fifth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one CaO6 octahedra and a cornercorner with one VO4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are a spread of V–O bond distances ranging from 1.67–1.81 Å. In the sixth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one CaO6 octahedra and a cornercorner with one VO4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of V–O bond distances ranging from 1.63–1.80 Å. There are four inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.82–1.87 Å. In the second Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.84–1.87 Å. In the third Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.83 Å) and two longer (1.87 Å) Cu–O bond length. In the fourth Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.83 Å) and two longer (1.85 Å) Cu–O bond length. There are twenty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one V5+, and one Cu3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one V5+, and one Cu3+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent V5+ atoms. In the fourth O2- site, O2- is bonded in a single-bond geometry to one V5+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and one V5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one V5+, and one Cu3+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two V5+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one V5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one V5+, and one Cu3+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one V5+ and one Cu3+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu3+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to one V5+ and one Cu3+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two V5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one V5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one V5+ and one Cu3+ atom. In the sixteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+, one V5+, and one Cu3+ atom. In the seventeenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one V5+ atom. In the eighteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one V5+ and one Cu3+ atom. In the nineteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu3+ atom. In the twentieth O2- site, O2- is bonded in a single-bond geometry to one V5+ atom. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent V5+ atoms. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu3+ atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-29. Materials Data on CaV4(CuO7)2 by Materials Project. https://doi.org/10.17188/1318506

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↗