Engineering Papers⌕ Search

DOE OSTI · 1676089

Materials Data on CaMgCd by Materials Project

Abstract

CaMgCd crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 12-coordinate geometry to four Ca, five Mg, and seven Cd atoms. There are a spread of Ca–Ca bond distances ranging from 3.66–3.78 Å. There are a spread of Ca–Mg bond distances ranging from 3.58–3.61 Å. There are a spread of Ca–Cd bond distances ranging from 3.53–3.57 Å. In the second Ca site, Ca is bonded in a 12-coordinate geometry to three equivalent Ca, seven Mg, and five Cd atoms. There are a spread of Ca–Mg bond distances ranging from 3.55–3.62 Å. There are a spread of Ca–Cd bond distances ranging from 3.49–3.54 Å. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to six Ca and six Cd atoms to form distorted MgCa6Cd6 cuboctahedra that share corners with four equivalent CdCa6Mg4Cd2 cuboctahedra, corners with fourteen MgCa6Cd6 cuboctahedra, edges with six MgCa6Cd6 cuboctahedra, faces with four equivalent MgCa6Mg4Cd2 cuboctahedra, and faces with fourteen CdCa6Mg4Cd2 cuboctahedra. There are a spread of Mg–Cd bond distances ranging from 2.98–3.06 Å. In the second Mg site, Mg is bonded to six Ca, four Mg, and two equivalent Cd atoms to form distorted MgCa6Mg4Cd2 cuboctahedra that share corners with eight MgCa6Cd6 cuboctahedra, corners with ten CdCa6Mg4Cd2 cuboctahedra, edges with two equivalent MgCa6Mg4Cd2 cuboctahedra, edges with four equivalent CdCa6Mg2Cd4 cuboctahedra, faces with eight CdCa6Mg4Cd2 cuboctahedra, and faces with ten MgCa6Cd6 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 2.98–3.06 Å. Both Mg–Cd bond lengths are 3.06 Å. In the third Mg site, Mg is bonded to six Ca, four equivalent Mg, and two equivalent Cd atoms to form distorted MgCa6Mg4Cd2 cuboctahedra that share corners with six MgCa6Cd6 cuboctahedra, corners with twelve CdCa6Mg4Cd2 cuboctahedra, edges with six MgCa6Cd6 cuboctahedra, faces with eight equivalent MgCa6Mg4Cd2 cuboctahedra, and faces with ten CdCa6Mg4Cd2 cuboctahedra. Both Mg–Cd bond lengths are 3.06 Å. There are two inequivalent Cd sites. In the first Cd site, Cd is bonded to six Ca, four Mg, and two equivalent Cd atoms to form distorted CdCa6Mg4Cd2 cuboctahedra that share corners with four equivalent CdCa6Mg2Cd4 cuboctahedra, corners with eight MgCa6Cd6 cuboctahedra, edges with six equivalent CdCa6Mg4Cd2 cuboctahedra, faces with eight CdCa6Mg4Cd2 cuboctahedra, and faces with twelve MgCa6Cd6 cuboctahedra. Both Cd–Cd bond lengths are 3.12 Å. In the second Cd site, Cd is bonded to six Ca, two equivalent Mg, and four Cd atoms to form distorted CdCa6Mg2Cd4 cuboctahedra that share corners with eight CdCa6Mg4Cd2 cuboctahedra, corners with ten MgCa6Mg4Cd2 cuboctahedra, edges with two equivalent CdCa6Mg2Cd4 cuboctahedra, edges with four equivalent MgCa6Mg4Cd2 cuboctahedra, faces with eight MgCa6Cd6 cuboctahedra, and faces with ten CdCa6Mg4Cd2 cuboctahedra. There are one shorter (2.97 Å) and one longer (3.10 Å) Cd–Cd bond lengths.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-05-02. Materials Data on CaMgCd by Materials Project. https://doi.org/10.17188/1676089

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↗