Search NASA⌕ Search

DOE OSTI · 1475851

Materials Data on Ca7MgCo7CuO24 by Materials Project

Abstract

Ca7MgCo7CuO24 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with twelve CaO12 cuboctahedra, faces with two equivalent MgO12 cuboctahedra, faces with four equivalent CaO12 cuboctahedra, a faceface with one CuO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.66–2.68 Å. In the second Ca site, Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with four equivalent MgO12 cuboctahedra, corners with eight equivalent CaO12 cuboctahedra, faces with six CaO12 cuboctahedra, a faceface with one CuO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.66–2.70 Å. In the third Ca site, Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with twelve equivalent CaO12 cuboctahedra, faces with six equivalent CaO12 cuboctahedra, a faceface with one CuO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.66–2.68 Å. Mg is bonded to twelve O atoms to form MgO12 cuboctahedra that share corners with twelve equivalent CaO12 cuboctahedra, faces with six equivalent CaO12 cuboctahedra, a faceface with one CuO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.64–2.67 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four equivalent CoO6 octahedra, a faceface with one MgO12 cuboctahedra, and faces with seven CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is two shorter (1.86 Å) and four longer (1.90 Å) Co–O bond length. In the second Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, a faceface with one MgO12 cuboctahedra, and faces with seven CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Co–O bond lengths are 1.88 Å. In the third Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, a faceface with one MgO12 cuboctahedra, and faces with seven CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is three shorter (1.89 Å) and three longer (1.90 Å) Co–O bond length. Cu is bonded to six O atoms to form CuO6 octahedra that share corners with six equivalent CoO6 octahedra, a faceface with one MgO12 cuboctahedra, and faces with seven CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is three shorter (1.91 Å) and three longer (1.92 Å) Cu–O bond length. There are six inequivalent O sites. In the first O site, O is bonded in a distorted linear geometry to three Ca, one Mg, one Co, and one Cu atom. In the second O site, O is bonded in a distorted linear geometry to three Ca, one Mg, and two Co atoms. In the third O site, O is bonded in a distorted linear geometry to three Ca, one Mg, and two Co atoms. In the fourth O site, O is bonded to four Ca, one Co, and one Cu atom to form distorted OCa4CoCu octahedra that share corners with twelve OCa4Co2 octahedra, edges with four equivalent OCa4Co2 octahedra, and faces with four OCa4CoCu octahedra. The corner-sharing octahedra tilt angles range from 1–61°. In the fifth O site, O is bonded to four Ca and two Co atoms to form a mixture of distorted face, edge, and corner-sharing OCa4Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–61°. In the sixth O site, O is bonded to four Ca and two Co atoms to form distorted OCa4Co2 octahedra that share corners with twelve OCa4CoCu octahedra, edges with four equivalent OCa4Co2 octahedra, and faces with four OCa4Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–61°.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-03. Materials Data on Ca7MgCo7CuO24 by Materials Project. https://doi.org/10.17188/1475851

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↗