Most people who have a smartphone have had the experience of feeling the device overheat and even shut itself down until it resumes a normal temperature. This overheating can damage electronic component or even cause them to explode or catch fire, which can create a dangerous situation.
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| A new hydrogel developed by scientists in China and California can cool off electronics and generate electricity from their waste heat. (Image source: Nano Letters, Wuhan University, and UCLA) |
To try to find a solution to this problem, researchers from Wuhan University in China and the University of California Los Angeles (UCLA) have developed a new hydrogel material that serves a unique dual function—it can cool down electronics, such as mobile-phone batteries, and also turn their waste heat into electricity.
“Efficient heat removal and recovery are two conflicting processes that are difficult to achieve simultaneously,” researchers wrote in an abstract for a paper on their work in the ACS journal Nano Letters.
Indeed, scientists so far have been able to design devices that can do one or the other, but not both, which is why the team set out to create what’s called a smart thermogalvanic hydrogel that could perform both these functions.
Material Composition and Behavior
The hydrogel researchers developed is comprised of a polyacrylamide framework infused with water and specific ions. Heating the hydrogel causes two of the ions (ferricyanide and ferrocyanide) to transfer electrons between electrodes, which generates electricity.
At the same time, water inside the hydrogel evaporated, which cooled the material. Then, after these reactions are complete, the material can regenerate itself by absorbing water from the surrounding air.
To demonstrate how the hydrogel can work in a device setting, researchers attached a hydrogel film with a thickness of 2 millimeters to a mobile-phone battery while operating and discharging energy quickly.
What they discovered from this test is that some of the waste heat was converted into 5 μW of electricity, decreasing the battery’s temperature by 68 degrees Fahrenheit.
This reduction in working temperature allows for the battery to operate safely, while the electricity generated during the process could monitor the battery or control the cooling system.
The team plans to continue its work to explore the dual properties of the hydrogel and its performance in other electronic devices for future commercial application.
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Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.