Flexible thermoelectric generator with liquid metal interconnects and low thermal conductivity silicone filler

• Published in: Npj flexible electronics 2021-03, Vol.5 (1), p.1-12, Article 5
• Main Authors: Padmanabhan Ramesh, Viswanath, Sargolzaeiaval, Yasaman, Neumann, Taylor, Misra, Veena, Vashaee, Daryoosh, Dickey, Michael D., Ozturk, Mehmet C.
• Format: Article
• Language: English
• Subjects: 639/166; 706/4066; Aerogels; Casting; Chemistry and Materials Science; Elastomers; Electrical resistivity; Electronics; Electronics and Microelectronics; Gallium; Heat conductivity; Heat transfer; Instrumentation; Interconnections; Liquid metals; Materials Science; Optical and Electronic Materials; Particulate composites; Particulates; Polydimethylsiloxane; Polymer Sciences; Power management; Silicone resins; Silicones; Thermal conductivity; Thermoelectric generators; Thermoelectricity; Wearable technology; Wrist
• ISSN: 2397-4621; 2397-4621
• DOI: 10.1038/s41528-021-00101-3

Harvesting body heat using thermoelectricity provides a promising path to realizing self-powered, wearable electronics that can achieve continuous, long-term, uninterrupted health monitoring. This paper reports a flexible thermoelectric generator (TEG) that provides efficient conversion of body heat to electrical energy. The device relies on a low thermal conductivity aerogel–silicone composite that secures and thermally isolates the individual semiconductor elements that are connected in series using stretchable eutectic gallium-indium (EGaIn) liquid metal interconnects. The composite consists of aerogel particulates mixed into polydimethylsiloxane (PDMS) providing as much as 50% reduction in the thermal conductivity of the silicone elastomer. Worn on the wrist, the flexible TEGs present output power density figures approaching 35 μWcm − 2 at an air velocity of 1.2 ms − 1 , equivalent to walking speed. The results suggest that these flexible TEGs can serve as the main energy source for low-power wearable electronics.