Using Hydrogel to Cool Down Electronics and Convert Waste Into Electricity

April 30, 2020 by Luke James

The thin polymer-based hydrogel film can be strapped to batteries to convert heat to electricity. It works by transferring electrons when heated to generate power.

Components like batteries, LEDs, and microprocessors generate heat during operation. Sometimes, this can lead to overheating which can reduce the efficiency, reliability, and lifespan of devices. Now, researchers from Wuhan and California have reportedly developed a polymer-based hydrogel that can cool down electronics and convert their waste heat into electricity.

The team’s research, published in the journal Nano Letters, describes how when attached to a heat source, the thermogalvanic hydrogel film is able to achieve efficient evaporating cooling while simultaneously converting a portion of the waste heat into electricity. 

The thermogalvanic hydrogel, which is strapped to the battery, is able to change its structure in response to temperature. It was made using a polyacrylamide framework consisting of an organic polymer, lubricant, and an oil recovery agent. This framework is then infused with water and ions.


A hydrogel that cools off electronics and generates electricity from their waste.

The hydrogel developed by researchers. Which is used to cool off electronics and generate electricity from their waste heat. Image credited to the American Chemical Society


Converting Waste Heat Into Electricity

When the hydrogel is heated up, two of the ions—ferricyanide and ferrocyanide—transfer electrons between electrodes, generating electricity. In the meantime, the water inside of the hydrogel evaporates, cooling it down. The hydrogel then regenerated itself by absorbing water from the surrounding air. 

The researchers tested their film on a smartphone battery and found that its temperature dropped by 68 degrees Fahrenheit (20 degrees Celsius). Some of the waste heat was also converted into electricity, marking the first time that scientists have developed a device that can do both at the same time. 

"The reduced working temperature ensures safe operation of the battery, and the electricity harvested is sufficient for monitoring the battery or controlling the cooling system." said Dr. Xuejiao Hu from Wuhan University in China.