Search NASA⌕ Search

DOE OSTI · 1276004

Materials Data on U4Ga12Rh by Materials Project

Abstract

U4RhGa12 crystallizes in the cubic Im-3m space group. The structure is three-dimensional. U is bonded to twelve Ga atoms to form UGa12 cuboctahedra that share corners with twelve equivalent UGa12 cuboctahedra, edges with twelve equivalent GaU4Ga8 cuboctahedra, faces with six equivalent UGa12 cuboctahedra, faces with six equivalent GaU4Ga8 cuboctahedra, and faces with two equivalent RhGa6 octahedra. There are six shorter (3.05 Å) and six longer (3.07 Å) U–Ga bond lengths. Rh is bonded to six equivalent Ga atoms to form RhGa6 octahedra that share corners with twenty-four equivalent GaU4Ga8 cuboctahedra and faces with eight equivalent UGa12 cuboctahedra. All Rh–Ga bond lengths are 2.51 Å. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded to four equivalent U and eight Ga atoms to form distorted GaU4Ga8 cuboctahedra that share corners with four equivalent GaU4Ga8 cuboctahedra, corners with four equivalent RhGa6 octahedra, edges with eight equivalent UGa12 cuboctahedra, edges with eight equivalent GaU4Ga8 cuboctahedra, faces with four equivalent UGa12 cuboctahedra, and faces with six equivalent GaU4Ga8 cuboctahedra. The corner-sharing octahedral tilt angles are 50°. There are four shorter (2.81 Å) and four longer (3.05 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a distorted single-bond geometry to four equivalent U, one Rh, and four equivalent Ga atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-07-15. Materials Data on U4Ga12Rh by Materials Project. https://doi.org/10.17188/1276004

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↗