As wearable electronics and soft robotics advance, conventional energy storage devices struggle to meet the demands for mechanical flexibility and extreme-temperature operation. Now, researchers from Sungkyunkwan University, led by Professor Sungjune Park, have developed a breakthrough hydrogel electrolyte that enables stretchable supercapacitors to perform reliably from -40°C to 80°C.
Why This Electrolyte Matters
Traditional hydrogel electrolytes face a critical trade-off: high water content enables ionic conductivity but causes freezing at sub-zero temperatures and poor mechanical strength. The novel PSLM/LiCl hydrogel overcomes these limitations by using liquid metal nanoparticles as polymerization initiators and introducing hydrophobic stearyl methacrylate (SMA) associations—creating dense physical cross-linking networks that deliver both ultra-stretchability and anti-freezing capability.
Innovative Design and Mechanism
The material is synthesized through liquid metal-initiated free-radical polymerization, where gallium nanoparticles generate radicals to cross-link acrylamide and acrylic acid within one minute. SMA segments form hydrophobic associations acting as dynamic cross-linking points, while subsequent LiCl immersion disrupts water hydrogen bonding to depress the freezing point below -40°C. This dual-network structure maintains ionic pathways even under severe deformation.
Outstanding Performance
The hydrogel achieves 907% elongation at break, 766 kPa tensile strength, and 4.35 S m -1 ionic conductivity at 25°C—retaining 3.39 S m -1 and 897% stretchability at -20°C. Assembled supercapacitors deliver 93.52 mF cm -2 areal capacitance with exceptional durability: 98% capacitance retention over 45,000 cycles, surpassing most reported hydrogel-based devices. The system operates stably across bending angles up to 180° and temperatures from -20°C to 80°C.
Applications and Future Outlook
Three series-connected units power commercial LEDs for over one minute, demonstrating practical viability for next-generation wearable and cold-climate energy storage. This work establishes a versatile platform for soft, deformable electronics requiring reliable performance in extreme environments.
Nano-Micro Letters
News article
Ultra‑Stretchable Anti‑Freezing Hydrogel Electrolytes Cross‑Linked by Liquid Metal Particle Initiators Toward Soft Energy Storage Devices
13-Mar-2026