Search NASA⌕ Search

DOE OSTI · 1747466

Materials Data on TiAl3Ge by Materials Project

Abstract

Al3GeTi crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. Ti is bonded to four equivalent Ti, six Al, and two equivalent Ge atoms to form distorted TiTi4Al6Ge2 cuboctahedra that share corners with four equivalent TiTi4Al6Ge2 cuboctahedra, corners with four equivalent AlAl10Ge2 cuboctahedra, corners with two equivalent AlAl4Ge5 square pyramids, edges with twelve AlTi4Al8 cuboctahedra, faces with five AlTi4Al8 cuboctahedra, and faces with eight equivalent TiTi4Al6Ge2 cuboctahedra. All Ti–Ti bond lengths are 2.83 Å. There are two shorter (2.83 Å) and four longer (2.85 Å) Ti–Al bond lengths. Both Ti–Ge bond lengths are 2.73 Å. There are five inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Al and five Ge atoms to form distorted AlAl4Ge5 square pyramids that share corners with four equivalent TiTi4Al6Ge2 cuboctahedra, corners with four equivalent AlTi4Al8 cuboctahedra, corners with four equivalent AlAl4Ge5 square pyramids, edges with twelve AlTi4Al8 cuboctahedra, faces with five AlTi4Al8 cuboctahedra, and faces with four equivalent AlAl4Ge5 square pyramids. All Al–Al bond lengths are 2.91 Å. There are one shorter (2.54 Å) and four longer (2.84 Å) Al–Ge bond lengths. In the second Al site, Al is bonded in a 5-coordinate geometry to four equivalent Ti and five Ge atoms. There are one shorter (2.57 Å) and four longer (2.84 Å) Al–Ge bond lengths. In the third Al site, Al is bonded to four equivalent Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent AlTi4Al8 cuboctahedra, corners with four equivalent AlAl4Ge5 square pyramids, edges with eight equivalent TiTi4Al6Ge2 cuboctahedra, edges with eight equivalent AlAl10Ge2 cuboctahedra, faces with four equivalent TiTi4Al6Ge2 cuboctahedra, faces with twelve AlTi4Al8 cuboctahedra, and a faceface with one AlAl4Ge5 square pyramid. There are four shorter (2.83 Å) and four longer (2.88 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded to four equivalent Ti and eight Al atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent AlTi4Al8 cuboctahedra, edges with eight equivalent TiTi4Al6Ge2 cuboctahedra, edges with eight equivalent AlAl10Ge2 cuboctahedra, edges with four equivalent AlAl4Ge5 square pyramids, faces with four equivalent TiTi4Al6Ge2 cuboctahedra, and faces with twelve AlTi4Al8 cuboctahedra. All Al–Al bond lengths are 2.88 Å. In the fifth Al site, Al is bonded to ten Al and two equivalent Ge atoms to form distorted AlAl10Ge2 cuboctahedra that share corners with four equivalent TiTi4Al6Ge2 cuboctahedra, corners with four equivalent AlAl10Ge2 cuboctahedra, edges with four equivalent TiTi4Al6Ge2 cuboctahedra, edges with eight AlTi4Al8 cuboctahedra, edges with four equivalent AlAl4Ge5 square pyramids, a faceface with one TiTi4Al6Ge2 cuboctahedra, faces with twelve AlTi4Al8 cuboctahedra, and faces with two equivalent AlAl4Ge5 square pyramids. All Al–Al bond lengths are 2.83 Å. Both Al–Ge bond lengths are 2.78 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to four equivalent Ti and five Al atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to nine Al atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-03. Materials Data on TiAl3Ge by Materials Project. https://doi.org/10.17188/1747466

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↗