Stretchable thermoelectric generator for wearable power source and temperature detection applications

Wearable thermoelectric generators are attracting tremendous interest due to their capability of converting the human body heat into electricity for powering electronics. In order to reduce the parasitic thermal resistance and enhance the efficiency of the energy harvesting process, the compliance of the device is required by introducing stretchable structures or materials. Thus, in this work, we present a novel stretchable thermoelectric generator (STEG) with 50 pairs of bulk thermoelectric legs connected by the kirigami-inspired flexible electrodes. The device was fabricated by a sacrificial layer assisted soldering fabrication method and its generation performances were characterized under natural and forced convection, as well as constant temperature difference conditions, respectively. The results indicated that the generated power density of the STEG under convection was enhanced by improving the cold-side air velocity, and the power density of the device under constant temperature difference conditions could be promoted with order of magnitudes to 2.7 mW/cm2 at AT = 50 K. Besides, the STEG features reliable during the cycling of 30 % tensile strain load and bending with a radius of 5 mm, respectively. Finally, various practical applications of the STEG were investigated including the wearable power supply and temperature detector for human proximity/contact testing and high-temperature alert. Our results demonstrate that the proposed STEG configuration displays high output performance that could be utilized for wearable electronics applications.