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

Viswanath Padmanabhan Ramesh,Veena Misra,Taylor Neumann,Mehmet C Ozturk,Yasaman Sargolzaeiaval,Michael D Dickey,Daryoosh Vashaee

doi:10.1038/s41528-021-00101-3

Viswanath Padmanabhan Ramesh, Veena Misra + Show 5 more

Open Access

https://doi.org/10.1038/s41528-021-00101-3

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Abstract

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.

Highlights

The wearable electronics industry is growing with many promising applications in health and performance monitoring
We demonstrate that aerogel inclusions in PDMS can reduce the thermal conductivity of the material by as heating/cooling as well as Joule heating, which are both secondorder effects[35]
The thermal resistance of the thermoelectric generator (TEG), RTEG is in series with two parasitic resistances, Rbody on the body side and 25 thermoelectric legs connected in series

Summary

INTRODUCTION

The wearable electronics industry is growing with many promising applications in health and performance monitoring. These studies have focused on new flexible materials as well as conventional materials used in a variety of different architectures[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23] Many of these devices failed to match the performance of rigid TEGs either due to the lower quality of their thermoelectric materials or parasitic thermal and electrical resistances introduced by their device architectures.

AND DISCUSSION

Padmanabhan Ramesh et al 7

METHODS

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