A novel electrolyte technology that overcomes the persistent limitations of aqueous batteries has been developed by a Korean research team. The research team led by Professor Hoseok Park of the Department of Chemical Engineering of SKKU announced that they have succeeded in dramatically improving the cycle life and capacity of aqueous batteries simply by adding a small amount of a special material to the electrolyte.
Aqueous batteries have long been considered a promising alternative for energy storage systems due to their lower raw material costs compared to lithium-ion batteries, as well as their superior safety and environmental friendliness stemming from the use of water-based electrolytes. However, the uneven deposition of zinc on electrode surfaces during repeated charge-discharge cycles, along with parasitic side reactions between zinc metal and water in the electrolyte, have accelerated battery degradation and posed a major obstacle to commercialization.
To address these issues, the research team turned their attention to zwitterions — molecules that carry both a positive and a negative charge simultaneously within a single molecular structure. Although electrically neutral overall, zwitterions possess the unique ability to precisely regulate interactions with surrounding ions.
The zwitterionic additive developed by the team (C10) spontaneously self-assembles into nanostructures approximately 3.77 nm in diameter when introduced in small quantities into the electrolyte. These nanostructures serve two critical functions. First, they guide zinc ions to deposit uniformly and stably onto the electrode surface, suppressing uneven zinc plating. Second, they coat the zinc metal surface with a thin, uniform protective layer that effectively blocks parasitic side reactions with water and prevents corrosion.
Aqueous batteries incorporating the developed electrolyte achieved an ultralong-term cycling stability of over 2,800 hours of stable operation. Under high-capacity conditions, the batteries recorded an areal capacity of 8.10 mAh cm⁻², representing world-leading performance among aqueous batteries reported to date. The simultaneous improvement of both cycle life and capacity — two critical performance metrics — stands out as the defining achievement of this study.
Professor Hoseok Park remarked, "We have demonstrated that the performance of aqueous batteries can be substantially enhanced through a simple approach of adding a small amount of material to the electrolyte, without the need for expensive materials or complex fabrication processes." He added, "Beyond renewable energy storage, this technology holds potential for application in large-scale energy storage systems (ESS) for AI infrastructure and data centers, which are experiencing explosive growth."
This research was supported by the Leader Research Program and the Future-leading Pioneer Research Program funded by the Ministry of Science and ICT and the National Research Foundation of Korea. The findings were published on January 4th in Nano-Micro Letters (IF 36.3, top 1% in nanotechnology).