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Materials Developed for Sodium Rechargeable Battery by EEWS
The research group of Professor William Goddard III, You-Sung Jung, and Jang-Wook Choi from the Graduate School of Energy, Environment, Water, and Sustainability (EEWS) at KAIST has developed a new sodium-ion rechargeable battery which operates at a high voltage, can be charged, and stably discharges over 10,000 cycles. The research results were published in the online version of the Proceedings of the National Academy of Sciences of the United States of America (PNAS) on December 30, 2013.
Since the material costs of sodium rechargeable batteries is 30 to 40 times lower than lithium batteries, it has received attention as an energy saving tool for smart grids and as the next generation of lithium rechargeable batteries. Until now, sodium-ion rechargeable batteries have had issues with stability when charging and discharging. The research group developed a vanadium-based electrode to solve these problems.
The group said follow-up research will be continued to develop advanced technology on sodium rechargeable batteries as it is still currently in the beginning stages.
The research team: From left to right is Professors William Goddard, You-Sung Jung, and Jang-Wook Choi
2014.01.13 View 15618 -
A Substance with Amazingly Improved Efficiency of Capturing Carbon Dioxides Developed
From left to right: Prof.Ali Coskun, Prof. Cafer T. Yavuz and Prof. Yousung Jung
- Selectivity of CO2 increased by 300 times in comparison to nitrogen, published in Nature Communications-
KAIST EEWS graduate school’s joint research team led by Prof. Cafer T. Yavuz, Prof. Ali Coskun, and Prof. Yousung Jung has developed the world"s most efficient CO2 absorbent that has 300 times higher carbon dioxide selectivity in comparison to nitrogen.
Recently, the importance of CCS* technology, which is about capturing, storing and treating carbon dioxides, has begun to emerge world-widely as a practical alternative for the response to climate change.
* CCS : Carbon Capture and sequestration
Current carbon dioxide capturing technologies are wet capturing using liquid absorbent, dry capturing using solid absorbent and separation-membrane capturing using a thin membrane like a film.
For the places like power plant and forge, where the emission of carbon dioxides is huge, the main task is to maintain the capturing efficiency under extremely hot and humid conditions.
The previously studied dry absorbents, such as MOF or zeolite, had the disadvantages of instability in moist conditions and expensive cost for synthesis.
On the other hand, the research team"s newly discovered dry absorbent, named ‘Azo-COP’, can be synthesized without any expensive catalysts so the production cost is very low. It is also stable under hot and humid conditions.
COP is a structure consisting of simple organic molecules combined into porous polymer and is the first dry carbon dioxide capturing material developed by this research team.
The research team introduced an additional functional group called "Azo" to the substance, so that it can selectively capture carbon dioxides among the mixture of gas.
Azo-COP, which includes ‘Azo’ functional group, is manufactured easily by using common synthesis methods, and impurities are removed simply by using cheap solvents like water and acetone instead of expensive catalysts. As a result, the manufacturing cost has lowered drastically.
Especially, Azo-COP is combined with carbon dioxides by weak attraction force rather than chemical attraction so the recycling energy cost for the absorbent can be reduced innovatively, and it is expected to be used for capturing substances other than carbon dioxides in various areas as it is stable under extreme conditions even under 350 degrees Celsius.
This research is supported by Korea Carbon Capture&Sequestration R&D Center(Head: Sangdo Park) and KAIST EEWS planning group.
Prof. Cafer T. Yavuz and Prof. Ali Coskun said that “when Azo-COP is used for separation of CO2 and N2, the capturing efficiency has increased by hundred times.” He continued “This substance does not need any catalysts and has great chemical characteristics like water stability and structure stability so is expected to be used in various fields including carbon dioxides capturing”
Meanwhile, this research is published in ‘Nature’s stablemate ‘Nature Communications’ on 15th of Jan.
2013.02.24 View 16337