Search NASA⌕ Search

DOE OSTI · 1720439

Materials Data on Pr4Ho2Mn23 by Materials Project

Abstract

Ho2Pr4Mn23 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Ho is bonded in a 12-coordinate geometry to twelve Mn atoms. There are a spread of Ho–Mn bond distances ranging from 2.89–3.11 Å. There are two inequivalent Pr sites. In the first Pr site, Pr is bonded in a 12-coordinate geometry to twelve Mn atoms. There are a spread of Pr–Mn bond distances ranging from 2.99–3.13 Å. In the second Pr site, Pr is bonded in a 12-coordinate geometry to twelve Mn atoms. There are a spread of Pr–Mn bond distances ranging from 2.98–3.15 Å. There are ten inequivalent Mn sites. In the first Mn site, Mn is bonded to two equivalent Ho, two equivalent Pr, and eight Mn atoms to form MnPr2Ho2Mn8 cuboctahedra that share corners with twelve MnPr2HoMn9 cuboctahedra and faces with fourteen MnPr3Mn9 cuboctahedra. There are a spread of Mn–Mn bond distances ranging from 2.40–2.64 Å. In the second Mn site, Mn is bonded in a distorted q6 geometry to two equivalent Ho, one Pr, and nine Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.38–2.63 Å. In the third Mn site, Mn is bonded to three Pr and nine Mn atoms to form MnPr3Mn9 cuboctahedra that share corners with eight MnPr2HoMn9 cuboctahedra and faces with eleven MnPr2Ho2Mn8 cuboctahedra. There are a spread of Mn–Mn bond distances ranging from 2.43–2.63 Å. In the fourth Mn site, Mn is bonded to one Ho, two Pr, and nine Mn atoms to form a mixture of distorted corner and face-sharing MnPr2HoMn9 cuboctahedra. There are a spread of Mn–Mn bond distances ranging from 2.44–2.61 Å. In the fifth Mn site, Mn is bonded in a body-centered cubic geometry to eight Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.56–2.60 Å. In the sixth Mn site, Mn is bonded in a 10-coordinate geometry to two equivalent Ho, one Pr, and ten Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.58–2.99 Å. In the seventh Mn site, Mn is bonded in a 10-coordinate geometry to three Pr and ten Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.67–3.01 Å. In the eighth Mn site, Mn is bonded in a 10-coordinate geometry to one Ho, two Pr, and ten Mn atoms. There are a spread of Mn–Mn bond distances ranging from 2.62–2.94 Å. In the ninth Mn site, Mn is bonded to one Ho, three Pr, and eight Mn atoms to form MnPr3HoMn8 cuboctahedra that share corners with ten MnPr3Mn9 cuboctahedra and faces with fourteen MnPr2Ho2Mn8 cuboctahedra. In the tenth Mn site, Mn is bonded to two equivalent Ho, two equivalent Pr, and eight Mn atoms to form MnPr2Ho2Mn8 cuboctahedra that share corners with eight MnPr2Ho2Mn8 cuboctahedra and faces with fourteen MnPr3Mn9 cuboctahedra.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-06-05. Materials Data on Pr4Ho2Mn23 by Materials Project. https://doi.org/10.17188/1720439

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↗