Excessive use of electronic devices can cause them to overheat, which can slow them down, damage components, or even cause an explosion or fire. Now, researchers who published an article about the invention in ACS Nano Letters have developed a hydrogel that can both cool electronics, such as cell phone batteries, and convert waste heat to electricity.
Some components of electronic devices, including batteries, LEDs, and computer microprocessors, generate heat during operation. Overheating can reduce the efficiency, reliability, and service life of devices, in addition to energy loss.
The researchers wanted to develop an intelligent term galvanic hydrogel that could convert waste heat to electricity while lowering the temperature of the device. So far, scientists have developed devices that can do one or the other, but not both at the same time.
The team made a hydrogel consisting of a polyacrylamide framework filled with water and specific ions. When they heated the hydrogel, two ions (ferricyanide and ferrocyanide) transferred electrons between the electrodes, generating electricity. Meanwhile, the water inside the hydrogel evaporated, cooling it. After use, the hydrogel restored itself by absorbing water from the surrounding air.
To demonstrate the new material, the researchers attached it to the cell phone battery during quick discharge. Part of the waste heat was converted to 5 μW of electricity, and the battery temperature decreased by 20°C. The lower operating temperature ensures safe battery operation, and the collected electricity is enough to charge the battery or control the cooling system.