Organic batteries are next-generation secondary batteries that replace metal electrodes, such as lithium and nickel, in commercial batteries with inexpensive organic materials. Domestic researchers have identified the cause of the phenomenon of organic battery electrodes dissolving into the electrolyte.
Professor Kwak Won-jin of the Ulsan National Institute of Science and Technology (UNIST) and his research team have discovered that strong interactions between the solvent and the cation occurring within the electrolyte enhance the leaching phenomenon of organic battery electrodes through collaborative research with Professor Choi Jun-myeong and his research team from Hanyang University's Department of Mechanical Engineering. The research findings were published in the international scientific journal "ACS NANO" on Jan. 14.
The electrodes of organic batteries can be mass-produced cheaply in factories, but the leaching phenomenon of battery electrodes dissolving into the electrolyte has resulted in a short battery lifespan. Various methods have emerged to solve this issue, but the exact cause of the leaching phenomenon has not been clearly identified.
The research team revealed that strong interactions between the solvent and the cation lead to "co-intercalation," which causes the leaching phenomenon. Co-intercalation refers to the phenomenon where the solvent molecules are pulled along when cations enter the internal microstructure of the electrode within the electrolyte. At this point, the microstructure of the electrode material expands, causing the electrode material to flow out easily. When the interaction between the solvent and cation is weak, only the cation enters the electrode.
By varying the types of cations in the electrolyte to lithium, sodium, and potassium during experiments, it was found that when using lithium ions, the interaction energy between the cations and solvent molecules was the greatest, and the leaching phenomenon occurred strongly, resulting in the thinnest electrode thickness.
Lee Hyun-wook, a researcher at UNIST and the first author of the paper, noted, "Previous research has primarily focused on changing the electrode material or structure to address the leaching phenomenon, but this study has identified the fundamental causes of leaching." Professor Kwak Won-jin stated, "This research has confirmed for the first time that the leaching of electrode materials is attributed not only to solubility but also to interactions within the electrolyte and the resulting changes in mechanisms, providing a specific electrolyte design strategy."
References
ACS Nano (2025), DOI: https://doi.org/10.1021/acsnano.4c13999