Search NASA⌕ Search

DOE OSTI · 1202151

Materials Data on Li4Ge9O20 by Materials Project

Abstract

Li4Ge9O20 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 2.03–2.46 Å. In the second Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.93–2.42 Å. In the third Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.21–2.63 Å. There are five inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six O2- atoms to form GeO6 octahedra that share corners with four GeO4 tetrahedra, a cornercorner with one GeO5 trigonal bipyramid, and an edgeedge with one GeO5 trigonal bipyramid. There are a spread of Ge–O bond distances ranging from 1.86–2.02 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent GeO6 octahedra, a cornercorner with one GeO4 tetrahedra, and a cornercorner with one GeO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 29–59°. There are a spread of Ge–O bond distances ranging from 1.75–1.80 Å. In the third Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO6 octahedra, corners with two GeO4 tetrahedra, and a cornercorner with one GeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 62°. There is two shorter (1.76 Å) and two longer (1.78 Å) Ge–O bond length. In the fourth Ge4+ site, Ge4+ is bonded to five O2- atoms to form distorted GeO5 trigonal bipyramids that share a cornercorner with one GeO6 octahedra, corners with three GeO4 tetrahedra, and an edgeedge with one GeO6 octahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of Ge–O bond distances ranging from 1.78–2.27 Å. In the fifth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent GeO6 octahedra, corners with two equivalent GeO4 tetrahedra, and corners with two equivalent GeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 61°. There is two shorter (1.78 Å) and two longer (1.79 Å) Ge–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded to two Li1+ and two Ge4+ atoms to form distorted edge-sharing OLi2Ge2 trigonal pyramids. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two Ge4+ atoms. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Li1+ and two Ge4+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Li1+ and three Ge4+ atoms. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Li1+ and two Ge4+ atoms. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to one Li1+ and two Ge4+ atoms. In the seventh O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Li1+ and two Ge4+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+ and two Ge4+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and two Ge4+ atoms. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to two Ge4+ atoms.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-05. Materials Data on Li4Ge9O20 by Materials Project. https://doi.org/10.17188/1202151

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↗