Search NASA⌕ Search

DOE OSTI · 1475811

Materials Data on Sr6Ca2Fe7CoO24 by Materials Project

Abstract

Sr6Ca2Fe7CoO24 is (Cubic) Perovskite-derived structured and crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. there are three inequivalent Sr sites. In the first Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with two equivalent CaO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, a faceface with one CoO6 octahedra, and faces with seven FeO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.74–2.76 Å. In the second Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, corners with eight equivalent CaO12 cuboctahedra, faces with six SrO12 cuboctahedra, a faceface with one CoO6 octahedra, and faces with seven FeO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.75–2.79 Å. In the third Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with two equivalent SrO12 cuboctahedra, faces with four equivalent CaO12 cuboctahedra, a faceface with one CoO6 octahedra, and faces with seven FeO6 octahedra. There are four shorter (2.73 Å) and eight longer (2.75 Å) Sr–O bond lengths. Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with four equivalent CaO12 cuboctahedra, corners with eight equivalent SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, a faceface with one CoO6 octahedra, and faces with seven FeO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.70–2.76 Å. There are five inequivalent Fe sites. In the first Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Fe–O bond distances ranging from 1.93–1.97 Å. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent CoO6 octahedra, corners with four equivalent FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Fe–O bond distances ranging from 1.92–2.06 Å. In the third Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with two equivalent CoO6 octahedra, corners with four FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Fe–O bond distances ranging from 1.93–1.96 Å. In the fourth Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is one shorter (1.92 Å) and five longer (1.94 Å) Fe–O bond length. In the fifth Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Fe–O bond distances ranging from 1.93–1.96 Å. Co is bonded to six O atoms to form CoO6 octahedra that share corners with six FeO6 octahedra, faces with two equivalent CaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 1.83–1.93 Å. There are ten inequivalent O sites. In the first O site, O is bonded to three Sr, one Ca, and two Fe atoms to form a mixture of distorted edge, corner, and face-sharing OSr3CaFe2 octahedra. The corner-sharing octahedra tilt angles range from 0–61°. In the second O site, O is bonded in a distorted linear geometry to three Sr, one Ca, and two Fe atoms. In the third O site, O is bonded to three Sr, one Ca, and two Fe atoms to form a mixture of distorted edge, corner, and face-sharing OSr3CaFe2 octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the fourth O site, O is bonded to three Sr, one Ca, one Fe, and one Co atom to form a mixture of distorted edge, corner, and face-sharing OSr3CaFeCo octahedra. The corner-sharing octahedra tilt angles range from 0–61°. In the fifth O site, O is bonded to four Sr and two Fe atoms to form distorted OSr4Fe2 octahedra that share corners with sixteen OSr3CaFe2 octahedra, edges with four OSr4FeCo octahedra, and faces with six OSr3CaFe2 octahedra. The corner-sharing octahedra tilt angles range from 1–61°. In the sixth O site, O is bonded to four Sr, one Fe, and one Co atom to form distorted OSr4FeCo octahedra that share corners with twenty OSr3CaFe2 octahedra, edges with four equivalent OSr4Fe2 octahedra, and faces with four equivalent OSr3CaFeCo octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the seventh O site, O is bonded in a distorted linear geometry to two equivalent Sr, two equivalent Ca, and two Fe atoms. In the eighth O site, O is bonded in a distorted linear geometry to two equivalent Sr, two equivalent Ca, one Fe, and one Co atom. In the ninth O site, O is bonded to four Sr and two Fe atoms to form distorted OSr4Fe2 octahedra that share corners with twelve OSr4FeCo octahedra, edges with four equivalent OSr4Fe2 octahedra, and faces with eight OSr3CaFe2 octahedra. The corner-sharing octahedra tilt angles range from 1–60°. In the tenth O site, O is bonded in a distorted linear geometry to two equivalent Sr, two equivalent Ca, and two Fe atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Sr6Ca2Fe7CoO24 by Materials Project. https://doi.org/10.17188/1475811

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↗