Engineering Papers⌕ Search

DOE OSTI · 1280831

Materials Data on NaTiFeO4 by Materials Project

Abstract

NaFeTiO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.27–2.69 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent FeO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 19–51°. There are a spread of Ti–O bond distances ranging from 1.88–2.12 Å. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent TiO6 octahedra, edges with two equivalent TiO6 octahedra, and edges with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 19–51°. There are a spread of Fe–O bond distances ranging from 1.93–1.97 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ti4+, and two equivalent Fe3+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three equivalent Na1+ and two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded to one Ti4+ and three equivalent Fe3+ atoms to form distorted OTiFe3 trigonal pyramids that share a cornercorner with one ONa2Ti2Fe trigonal bipyramid, corners with two equivalent OTiFe3 trigonal pyramids, edges with two equivalent ONa2Ti2Fe trigonal bipyramids, and edges with two equivalent OTiFe3 trigonal pyramids. In the fourth O2- site, O2- is bonded to two equivalent Na1+, two equivalent Ti4+, and one Fe3+ atom to form distorted ONa2Ti2Fe trigonal bipyramids that share a cornercorner with one OTiFe3 trigonal pyramid, edges with two equivalent ONa2Ti2Fe trigonal bipyramids, and edges with two equivalent OTiFe3 trigonal pyramids.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-07-23. Materials Data on NaTiFeO4 by Materials Project. https://doi.org/10.17188/1280831

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↗