Engineering Papers⌕ Search

DOE OSTI · 1757043

Materials Data on TbGaGe2O7 by Materials Project

Abstract

TbGaGe2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Tb3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Tb–O bond distances ranging from 2.29–2.79 Å. Ga3+ is bonded to five O2- atoms to form GaO5 trigonal bipyramids that share corners with five GeO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.88–2.03 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with two equivalent GaO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.73–1.80 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with three equivalent GaO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.76–1.82 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Tb3+, one Ga3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Tb3+, one Ga3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Tb3+, one Ga3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Tb3+, one Ga3+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Tb3+ and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Tb3+, one Ga3+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Tb3+ and two Ge4+ atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-09-03. Materials Data on TbGaGe2O7 by Materials Project. https://doi.org/10.17188/1757043

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↗