Search NASA⌕ Search

DOE OSTI · 1475646

Materials Data on Sr2Ca6FeCo7O24 by Materials Project

Abstract

Sr2Ca6FeCo7O24 is (Cubic) Perovskite-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with twelve CaO12 cuboctahedra, faces with two equivalent SrO12 cuboctahedra, faces with four equivalent CaO12 cuboctahedra, a faceface with one FeO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.70–2.76 Å. There are two inequivalent Ca sites. In the first Ca site, Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, corners with eight CaO12 cuboctahedra, faces with two equivalent SrO12 cuboctahedra, faces with four CaO12 cuboctahedra, a faceface with one FeO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.65–2.73 Å. In the second Ca site, Ca is bonded to twelve O atoms to form CaO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, corners with eight equivalent CaO12 cuboctahedra, faces with six CaO12 cuboctahedra, a faceface with one FeO6 octahedra, and faces with seven CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.61–2.71 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Fe–O bond distances ranging from 1.91–2.03 Å. There are five 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 FeO6 octahedra, corners with four CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 1.87–1.90 Å. In the second Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There is four shorter (1.92 Å) and two longer (1.94 Å) Co–O bond length. In the third Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four equivalent CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 1.80–1.98 Å. In the fourth Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 1.84–1.96 Å. In the fifth Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent SrO12 cuboctahedra, and faces with six CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 1.85–1.91 Å. There are eleven inequivalent O sites. In the first O site, O is bonded to one Sr, three Ca, one Fe, and one Co atom to form distorted OSrCa3FeCo octahedra that share corners with fourteen OSrCa3FeCo octahedra, edges with four equivalent OSrCa3Co2 octahedra, and faces with four OSr2Ca2FeCo octahedra. The corner-sharing octahedra tilt angles range from 1–63°. In the second O site, O is bonded to one Sr, three Ca, and two Co atoms to form distorted OSrCa3Co2 octahedra that share corners with fourteen OSrCa3Co2 octahedra, edges with four OSrCa3FeCo octahedra, and faces with four OSr2Ca2FeCo octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the third O site, O is bonded to one Sr, three Ca, and two Co atoms to form distorted OSrCa3Co2 octahedra that share corners with fourteen OSrCa3FeCo octahedra, edges with four equivalent OSrCa3Co2 octahedra, and faces with four OSr2Ca2Co2 octahedra. The corner-sharing octahedra tilt angles range from 2–62°. In the fourth O site, O is bonded to two equivalent Sr, two equivalent Ca, one Fe, and one Co atom to form distorted OSr2Ca2FeCo octahedra that share corners with sixteen OSrCa3Co2 octahedra, edges with four OSr2Ca2Co2 octahedra, and faces with six OSrCa3FeCo octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the fifth O site, O is bonded to two equivalent Sr, two equivalent Ca, and two Co atoms to form distorted OSr2Ca2Co2 octahedra that share corners with sixteen OSrCa3FeCo octahedra, edges with four OSr2Ca2FeCo octahedra, and faces with six OSrCa3Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the sixth O site, O is bonded in a distorted linear geometry to four Ca, one Fe, and one Co atom. In the seventh O site, O is bonded in a distorted linear geometry to four Ca and two Co atoms. In the eighth O site, O is bonded to two equivalent Sr, two equivalent Ca, and two Co atoms to form distorted OSr2Ca2Co2 octahedra that share corners with sixteen OSrCa3Co2 octahedra, edges with four OSr2Ca2FeCo octahedra, and faces with six OSrCa3FeCo octahedra. The corner-sharing octahedra tilt angles range from 1–62°. In the ninth O site, O is bonded to two equivalent Sr, two equivalent Ca, and two Co atoms to form distorted OSr2Ca2Co2 octahedra that share corners with sixteen OSrCa3FeCo octahedra, edges with four OSr2Ca2Co2 octahedra, and faces with six OSrCa3Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–63°. In the tenth O site, O is bonded in a distorted linear geometry to four Ca and two Co atoms. In the eleventh O site, O is bonded in a distorted linear geometry to four Ca and two Co atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-30. Materials Data on Sr2Ca6FeCo7O24 by Materials Project. https://doi.org/10.17188/1475646

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↗