"Thermoelectric Rubber" Offers New Solution for Wearable Energy Harvesting

On August 14, Qingdao University of Science and Technology announced that Professor Liu Kai has developed the first N-type thermoelectric elastomer, dubbed "thermoelectric rubber," providing a novel solution for energy harvesting in flexible electronics and wearable devices. The findings were published in the journal Nature on August 13.

Conventional thermoelectric devices primarily use inorganic thermoelectric materials, which are rigid and lack elasticity or shape adaptability, limiting their application in wearables. To address this, Liu Kai, building on research from Professor Lei Ting’s team at Peking University and Professor Hua Jing’s team at Qingdao University of Science and Technology, developed an N-type thermoelectric elastomer. This innovative material combines elasticity, stretchability, and thermoelectric conversion capabilities, opening new avenues for wearable energy harvesting.

Liu explained that the N-type thermoelectric elastomer was synthesized by integrating three strategies: homogeneous nanophase separation, thermally activated crosslinking, and directional doping. The material exhibits exceptional stretchability and resilience, with a tensile strain of up to 850%, rivaling conventional rubber. Its thermoelectric figure of merit (ZT) reaches 0.49 at 300 Kelvin, matching or surpassing existing flexible or plastic inorganic thermoelectric materials.

By precisely selecting elastomer-dopant combinations, the researchers not only enhanced the material’s stretchability but also promoted the formation of uniformly distributed semiconducting polymer nanofibers. This simultaneously improves electrical conductivity while reducing thermal conductivity, overcoming the long-standing trade-off between high efficiency and elastic tunability in thermoelectrics.

Leveraging this breakthrough, the team created the first elastic thermoelectric generator. Unlike inorganic thermoelectric devices, this generator requires no complex interconnects, conforms directly to skin, and maintains high fill factors with low thermal resistance. It combines high thermoelectric conversion efficiency with superior comfort and shape adaptability, demonstrating potential to power wearable electronics and biosensors.