The research group led by Prof. Sungjune Park from the Department of Chemical Engineering has developed an ultra-stretchable, anti-freezing hydrogel electrolyte using liquid metal particles. The material can stretch up to nine times its original length while maintaining stable electrochemical performance, even at −20 °C. This work provides a promising platform for energy storage devices that must operate reliably under extreme environmental conditions.
With the rapid growth of wearable electronics, there is increasing demand for energy storage systems that combine mechanical flexibility with environmental stability. However, conventional hydrogel electrolytes typically suffer from low mechanical strength and freezing at low temperatures, leading to significant performance degradation.
The research group used liquid metal particles as an initiator for polymerization. Under ultrasonication, the bulk liquid metal was broken into fine particles, which then initiated the polymerization of acrylamide and acrylic acid to form the hydrogel. This process eliminates the need for external stimuli such as heat or ultraviolet irradiation, simplifying fabrication and improving scalability.
The group added stearyl methacrylate (SMA), a hydrophobic material that does not mix well with water, to create physical crosslinking between polymer chains. These physical crosslinks act as reversible connections within the network. When an external force is applied, the bonds can break to dissipate energy and then easily reform once the stress is released, thereby imparting exceptional stretchability and mechanical robustness to the material. As a result, the elongation at break (defined as the maximum stretch before the material fails) reached up to 900% of its original length.
After soaking the hydrogel in a lithium chloride (LiCl) solution, it exhibited anti-freezing properties by suppressing hydrogen bonding between water molecules. It maintains both ionic conductivity and mechanical flexibility even at −20 °C, where conventional hydrogel systems typically fail. Energy storage devices fabricated with this electrolyte retained 98% of their performance after 45,000 charge-discharge cycles.
The research group noted, “For practical applications, it is essential to ensure long-term stability and reproducibility in large-area manufacturing processes.”
Prof. Park stated,
“This work introduces a new design strategy for hydrogel electrolytes based on liquid metal and provides a viable platform for next-generation wearable electronics and flexible energy storage systems operating under extreme conditions.”
The research results were published on March 13 in Nano-Micro Letters.
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