Search NASA⌕ Search

DOE OSTI · 1746574

Materials Data on CaZn2O8 by Materials Project

Abstract

CaZn2O8 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca is bonded to eight O atoms to form distorted CaO8 hexagonal bipyramids that share corners with four equivalent CaO8 hexagonal bipyramids and corners with four equivalent ZnO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.37–2.62 Å. Zn is bonded to four O atoms to form ZnO4 tetrahedra that share corners with two equivalent CaO8 hexagonal bipyramids and corners with two equivalent ZnO4 tetrahedra. There are a spread of Zn–O bond distances ranging from 1.93–2.06 Å. There are four inequivalent O sites. In the first O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca, one Zn, and one O atom. The O–O bond length is 1.36 Å. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca, one Zn, and one O atom. The O–O bond length is 1.50 Å. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Zn and one O atom. In the fourth O site, O is bonded in a 3-coordinate geometry to two equivalent Ca and one O atom.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on CaZn2O8 by Materials Project. https://doi.org/10.17188/1746574

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↗