Heat source free water floating carbon nanotube thermoelectric generators

Tomoyuki Chiba,Yuki Amma,Masayuki Takashiri

doi:10.1038/s41598-021-94242-0

Abstract

Thermoelectric generators (TEGs) produce electric power from environmental heat energy and are expected to play a key role in powering the Internet of things. However, they require a heat source to create a stable and irreversible temperature gradient. Overcoming these restrictions will allow the use of TEGs to proliferate. Therefore, we propose heat source-free water-floating carbon nanotube (CNT) TEGs. Output voltage and power are generated by the temperature gradient in the CNT films in which water pumping via capillary action leads to evaporation-induced cooling in selected areas. Furthermore, the output voltage and power increase when the films are exposed to sunlight and wind flow. These water-floating CNT TEGs demonstrate a pathway for developing wireless monitoring systems for water environments.

Highlights

Thermoelectric generators (TEGs) produce electric power from environmental heat energy and are expected to play a key role in powering the Internet of things
When a bundle of single-wall carbon nanotubes (SWCNTs) films floats on water, the water passes through the gaps in the SWCNT bundle and reaches the surface via capillary action
The flexible substrate comprises square holes arranged in a staggered pattern and each hole is covered by an edge of a rectangular SWCNT film

Summary

Introduction

Thermoelectric generators (TEGs) produce electric power from environmental heat energy and are expected to play a key role in powering the Internet of things They require a heat source to create a stable and irreversible temperature gradient. TEGs have been proposed as power supplies for wireless sensors and wearable devices that constitute the Internet of things (IoT)[9,10,11,12] These applications require TEGs that are small, lightweight, and mechanically flexible, without excessively high power generated by a large temperature gradient. Heat flows vertically to the heat source and the direction cannot be controlled without proper placement of the heat source and heat sink; p- and n-type materials are required to produce electric power efficiently Overcoming these weaknesses will help increase the applications of TEGs. One promising TEG structure for surmounting these obstacles is water-floating carbon nanotube (CNT) TEGs (see Fig. 1).

Methods

Conclusion