By introducing an atmospheric electrolyte, an open-space cell capable of rapid gas diffusion and movement has been developed, presenting a new electrochemical system form factor for next-generation energy and environmental cell technology.

The National Research Foundation of Korea (Chairman Lee Kwang-bok) announced that a research team led by Professor Ryu Won-hee (Sookmyung Women's University) has developed a new concept of a gas-phase reaction-based electrochemical cell structure. This structure departs from the classical electrochemical system structure based on liquid electrolytes, which restricts the free diffusion and transfer of gaseous reactants and products, by creating an open space around the electrodes.

Research on energy and environmental electrochemical systems that consume/produce various gases, such as oxygen or carbon dioxide in the atmosphere, to convert them into useful energy sources or capture greenhouse gases that cause air pollution is actively conducted worldwide. Additionally, after the COVID-19 crisis, public interest in atmospheric health, related to the detection and removal of viruses causing biological contamination in the air, has significantly increased.

Traditional electrochemical cell systems include liquid electrolytes for ion conduction and reaction interface formation, with electrodes fully immersed in the electrolyte, blocking contact with external air. However, they have a fundamental limitation in that the diffusion of gaseous reactants to the electrodes is difficult due to the low gas solubility in the liquid electrolyte. This makes the formation of a three-phase interface difficult during gas-based electrochemical reactions, resulting in very slow reaction rates.

In gas-consuming reactions, such as metal-air batteries or fuel cells, external pressure air injection is needed to facilitate the diffusion and transfer of gaseous reactants to the electrode within the electrolyte. In gas-generating reactions, such as water electrolysis systems, gaseous products generated on the electrode surface can form bubbles, deactivating the electrode surface.

Professor Ryu's research team implemented a new concept electrochemical cell by modifying the classic Daniell cell, opening the space around the electrodes without a bath containing liquid electrolytes, and directly spraying the electrolyte in aerosol form. To solve the ion conduction short-circuit problem due to the open space between electrodes, the team introduced a one-dimensional porous salt bridge network that enables ion conduction between the electrodes, confirming the feasibility of continuous electrochemical reactions. In the future, this research aims to expand the application of the developed open-space electrochemical system to energy, environmental, and bio applications, presenting the broad applicability of this system.

This research, supported by the Young Researchers Successor Project and the Group Research Center Project promoted by the Ministry of Science and ICT (or the Ministry of Education) and the National Research Foundation of Korea, was published in the international academic journal "Energy & Environmental Science" on May 17.

Operating Principle and Applications of Open-Space Electrochemical Cells Using Atmospheric Electrolytes

[Reference] Lim et al., (2024) Yoon Jeong Yoo, Boran Kim, Suji Kim, Ga Yoon Kim, and Won-Hee Ryu*, “Aeroelectrolyte for Atmospheric Open Electrochemical Cells”, Energy & Environmental Science, https://doi.org/10.1039/D4EE01252F

[Main Author] Yeji Lim(Sookmyung Women's University), Won-Hee Ryu(Sookmyung Women's University)

* Contact : whryu@sookmyung.ac.kr