A Battery That Catches Two Rabbits: 'Carbon Neutrality' and 'Hydrogen'

UNIST Professor Kim Geontae's Team Develops Simpler 'Aqueous Metal-Carbon Dioxide System' Without Membrane
Original Technology Evolving to Produce Hydrogen and Electricity from CO2 Dissolved in Water ... Published in Nano Energy

Schematic diagram of the charge-discharge energy cycle of the system developed by UNIST researchers.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] A new battery has been developed that simultaneously eliminates the greenhouse gas "carbon dioxide" and produces "hydrogen" and "electricity" more easily and quickly.

The research team led by Professor Kim Geon-tae of the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST, President Lee Yong-hoon) developed a "Membrane-free aqueous metal-carbon dioxide battery" system that does not require a membrane, which is a separator that separates the system.

Unlike the existing "aqueous metal-carbon dioxide system," this system has no electrode separator membrane, making the manufacturing process simpler, and it can operate continuously with only one type of electrolyte.

Professor Kim's team previously developed the world's first "aqueous metal-carbon dioxide system." The "aqueous metal-carbon dioxide system" is a system that converts carbon dioxide into hydrogen and electricity through a spontaneous chemical reaction in water acidified by dissolved carbon dioxide.

The newly developed "Membrane-free aqueous metal-carbon dioxide battery (Membrane-free Mg-CO2 Battery)" requires only an anode (magnesium metal), aqueous electrolyte, and cathode (catalyst).

It boasts a high hydrogen generation efficiency (Faraday efficiency) of 92%, and the oxygen and chlorine generated during the charging reaction can also be usefully utilized.

Carbon Capture, Utilization and Storage (CCUS) technology, which removes carbon dioxide while producing useful resources, is gaining attention.

Schematic diagram of various metal-carbon dioxide battery systems.

One such technology is the "metal-carbon dioxide battery" that produces electrical energy from carbon dioxide. However, metal-carbon dioxide batteries have the drawback of reduced battery capacity due to solid deposits accumulating on the electrodes as the reaction continues.

Jungwon Kim, a combined master's and doctoral course researcher in the Department of Energy Engineering at UNIST and the first author, explained, "The aqueous metal-carbon dioxide system is an efficient CCUS technology that can operate continuously because the reaction products exist in gaseous and ionic forms, unlike metal-carbon dioxide batteries."

The "membrane-free aqueous metal-carbon dioxide battery" developed by the research team has a structure similar to hydrogen fuel cells, requiring only a magnesium metal anode, aqueous electrolyte, and cathode (catalyst).

However, unlike fuel cells, the catalyst is immersed in water (aqueous electrolyte) and connected to the anode and conductor. When carbon dioxide is bubbled into the water, the entire reaction starts, carbon dioxide disappears, and electricity and hydrogen are produced.

Professor Donghyup Jeon of Dongguk University’s Department of Mechanical Systems Engineering said, "Simulation results allowed us to precisely identify the causes of performance degradation in the membrane-free aqueous metal-carbon dioxide battery," adding, "Through accurate diagnosis of the issues, it will be possible to develop carbon dioxide utilization batteries with improved performance."

Professor Kim Geontae of UNIST (from the left), Researcher Kim Jungwon, Researcher Joo Sangwook.

Professor Kim Geon-tae said, "With the 'membrane-free' technology that simplifies the manufacturing process while increasing carbon dioxide utilization, we can accelerate the commercialization of the aqueous metal-carbon dioxide system."

He added, "This research will not only develop a new carbon dioxide utilization system but also lead to many derivative studies."

The study involved Professor Donghyup Jeon of Dongguk University and Professor Liming Dai of the University of New South Wales.

The research results were published online on January 4 in "Nano Energy," a world-renowned journal in the energy field, and are scheduled for print publication. The research was supported by Korea East-West Power and the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT.

This content was produced with the assistance of AI translation services.