Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 1685960

Materials Data on Ti(FeO2)3 by Materials Project

View original source ↗Read source document ↗Export metadata ↓

Abstract

Ti(FeO2)3 is Ilmenite-like structured and crystallizes in the trigonal R3 space group. The structure is three-dimensional. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are three shorter (1.92 Å) and three longer (2.09 Å) Ti–O bond lengths. There are three inequivalent Fe+2.67+ sites. In the first Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with three equivalent FeO6 octahedra, corners with six equivalent TiO6 octahedra, edges with three equivalent FeO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–64°. There are three shorter (2.08 Å) and three longer (2.25 Å) Fe–O bond lengths. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with six equivalent FeO6 octahedra, edges with three equivalent FeO6 octahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedra tilt angles range from 44–57°. There are three shorter (2.02 Å) and three longer (2.09 Å) Fe–O bond lengths. In the third Fe+2.67+ site, Fe+2.67+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with nine FeO6 octahedra, edges with three equivalent TiO6 octahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 44–64°. There are three shorter (1.98 Å) and three longer (2.15 Å) Fe–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ti4+ and three Fe+2.67+ atoms to form a mixture of distorted edge and corner-sharing OTiFe3 trigonal pyramids. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to one Ti4+ and three Fe+2.67+ atoms.

Explore related subjects

36 MATERIALS SCIENCEcrystal structureFe-O-TiTi(FeO2)3

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on Ti(FeO2)3 by Materials Project. https://doi.org/10.17188/1685960

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

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↗