The material that could save industries heat

Date:
April 4, 2022
Source:
Tohoku University
Summary:
Scientists have found a common substance that can reversibly and
rapidly store and release relatively large amounts of low-grade
heat without decomposing. The research could lead to more efficient
reuse of industrial waste heat.



FULL STORY ========================================================================== Scientists in Japan have found a common substance that can reversibly
and rapidly store and release relatively large amounts of low-grade heat without decomposing. The research could lead to more efficient reuse of industrial waste heat. The results were published in the journalNature Communicationsand were a collaboration between scientists at Tohoku University's Institute for Materials Research and Rigaku Corporation,
a company that designs and manufactures X-ray-based measurement and
thermal analysis tools.


==========================================================================
In their investigations, the researchers used a layered manganese oxide
mineral containing potassium ions and crystal water. This mineral is
quite similar in its composition to birnessite, which is commonly found
on the Earth's surface.

The team fabricated their compound in the form of an insoluble
black powder and then examined its crystal structure using an X-ray diffractometer and a transmission electron microscope. They then examined
how the compound's structure changed when heated or cooled, and how much
and how quickly heat energy was stored and released.

Heating the material up to 200 degrees C dehydrated it by giving its
stored water molecules the energy they need to be released into the
surrounding atmosphere. When the dehydrated material was then cooled
below 120?C in a dry container and then exposed to humid air, it absorbed
water molecules and released its stored heat.

"This 'intercalation' mechanism, where water molecules are reversibly
inserted into a layered material, is very advantageous for heat storage,"
says Tohoku University materials scientist Tetsu Ichitsubo. "It
is very fast, reversible and the material's structure is well
maintained. Also, oxygen in the atmosphere doesn't degrade the layered manganese oxide crystal and water doesn't dissolve it. This makes it
an excellent candidate for waste-heat reuse in industrial settings."
This 'birnessite-type layered manganese dioxide with crystal water'
compound demonstrated better all-round performance compared to other
compounds currently being researched for heat storage purposes. "Our
material has a long lifetime, can reversibly store and release large
amounts of heat per unit volume, and rapidly charges and discharges,"
says Ichitsubo.

The researchers validated the results of their experiments with
theoretical calculations.

Next, they plan to work on increasing the amount of water molecules that
can be accommodated by the material in order to increase the amount of
heat energy it can store.


========================================================================== Story Source: Materials provided by Tohoku_University. Note: Content
may be edited for style and length.


========================================================================== Related Multimedia:
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Heat_released_from_manganese_oxide_material_when_water_molecules_enter
layered_structure ========================================================================== Journal Reference:
1. Takuya Hatakeyama, Norihiko L. Okamoto, Satoshi Otake, Hiroaki Sato,
Hongyi Li, Tetsu Ichitsubo. Excellently balanced
water-intercalation-type heat-storage oxide. Nature Communications,
2022; 13 (1) DOI: 10.1038/ s41467-022-28988-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220404105726.htm

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