Thermoelectric elastomer generates electricity from body heat
In future, an elastomer could generate the power required for wearables. It uses the heat difference between body temperature and the ambient air.
The thermoelectric elastomer on one hand generates electricity.
(Image: Peking University/Screenshot)
Chinese scientists at Peking University have developed a rubber-like polymer composite that can convert body heat into electricity. A wristband made from this material could be used to power a wearable without the need to recharge its battery with a charger. The battery is then supplied with energy by the elastomer wristband.
The polymer developed by the Chinese researchers works according to the principle of thermoelectricity. Temperature differences generate an electric current. With conductive material that is hot on one side and cold on the other, the electrons on the hot side have more energy. They then move to the cooler side. The flow of electrons generates electricity. The greater the temperature difference, the more electricity is generated.
The elastomer described by the researchers in the study “n-Type thermoelectric elastomers,” which was published in Nature, uses the temperature difference between the body heat of 37 °C and the surrounding air, which usually has a temperature of between 20 °C and 30 °C. The n-type material can be stretched up to 150 percent of its original length and then returns to its original shape. In addition, it can withstand loads that stretch it up to 850 percent before the material tears. Elastomers that can maintain their conductivity even under high mechanical stress are referred to as n-type thermoelastomers.
Conductive elastomer
To improve the electrical properties of the elastomer, i.e., to make it more conductive, the scientists added the dopant N-DMBI. The substance significantly increases the conductivity of the material. It can thus more effectively convert the heat difference between the inside and outside into electricity. Thanks to the stretchability of the material, the inside can fit snugly against the skin and thus efficiently absorb body heat. The outside takes on the temperature of the ambient air.
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The scientists see a wide range of applications. For example, wearables could be powered by the energy generated. For medical applications, such as health monitoring, the material could be embedded in clothing or worn as a plaster. The researchers at Peking University also believe that implanted devices could then be continuously supplied with electricity.
(olb)
