Tellurium-nanowire-doped thermoelectric hydrogel with high stretchability and seebeck coefficient for low-grade heat energy harvesting

To harvest low-grade heat energy from human body, flexible thermoelectric generators (TEGs) are highly necessitated and have attracted significant interests. However, developing novel thermoelectric materials with high stretchability and seebeck coefficient is still challenging. Here we report a tellurium-nanowire-doped (Te-NW-doped) PEDOT:PSS/polyvinyl alcohol (TPP) hydrogel with excellent mechanical and thermoelectric characteristics. The effect of Te-NWs doping on the thermoelectric characteristics has been systematically investigated and the optimized TPP hydrogel exhibits a large seebeck coefficient value of 787 μV K−1, a low thermal conductivity of 0.468 W m−1 K−1, and a high tensile strain value of ⁓ 400%. Furthermore, a wearable thermoelectric module with a staggered Z-shaped structure is developed to achieve a voltage output of 138 mV when it is applied on the human arm. After being integrated with a power management unit, the TPP TEG module enables the operation of electronic devices like a commercial calculator and a white LED, which exhibits great potential for applications in human heat energy harvesting and wearable electronics.