Researchers have developed a new hydrogel material that can stretch up to nine times its original length and continue working even in freezing temperatures.
The breakthrough could help improve future wearable electronics, flexible batteries, and other energy storage devices that need to operate reliably in harsh environments.
The study was led by Professor Sungjune Park and colleagues from the Department of Chemical Engineering and was recently published in Nano-Micro Letters.
As wearable technology becomes more popular, scientists are looking for better materials to power these devices.
Flexible smartwatches, health monitors, electronic skin, and other wearable gadgets require energy storage systems that can bend, stretch, and twist without losing performance.
However, many existing hydrogel electrolytes have important limitations. They are often mechanically weak and can freeze at low temperatures, causing their performance to drop significantly.
To solve these problems, the research team created a new type of hydrogel electrolyte using tiny particles of liquid metal.
The process begins with liquid metal being broken into microscopic particles using ultrasonic waves. These particles then trigger a chemical reaction that forms the hydrogel. Unlike many traditional manufacturing methods, the process does not require heating or ultraviolet light. This makes production simpler and could make large-scale manufacturing easier in the future.
The researchers also added a water-repelling material called stearyl methacrylate. This ingredient helps create temporary connections between the hydrogel’s polymer chains. These connections act like tiny shock absorbers inside the material.
When the hydrogel is stretched, some of these connections break and absorb the stress, preventing damage. Once the stretching force is removed, the connections can reform. This allows the material to remain both strong and highly flexible.
Tests showed that the hydrogel could stretch to 900% of its original length before breaking. In other words, a piece measuring 1 centimeter long could be stretched to about 9 centimeters.
The team then soaked the hydrogel in a lithium chloride solution. This step gave the material impressive anti-freezing properties. The lithium chloride helps prevent water molecules from forming the ice crystals that normally cause hydrogels to freeze.
As a result, the material remained flexible and electrically conductive even at temperatures as low as -20 degrees Celsius. At such temperatures, many conventional hydrogel electrolytes become stiff or stop functioning altogether.
The researchers also tested the hydrogel in energy storage devices. The devices retained 98% of their performance after 45,000 charge-discharge cycles, demonstrating excellent long-term durability.
According to the researchers, more work is needed to ensure stable large-scale manufacturing and long-term reliability for commercial products. However, the results suggest that the new hydrogel could become an important platform for next-generation flexible electronics.
By combining liquid metal technology with a highly stretchable and freeze-resistant design, the new material offers a promising solution for wearable devices and energy storage systems that must continue working under demanding conditions, whether they are bent, stretched, or exposed to extreme cold.
