Thermoelectric generator based on anisotropic wood aerogel for low-grade heat energy harvesting

Abstract

• A CNT/PEDOT-decorated thermoelectric network is constructed from wood-based framework. • The anisotropic structure is advantageous to convert low-grade heat energy. • Ordered porous structure and energy filtering effect enhance the TE performance. • Successful application as a device for waste heat energy harvesting and conversion. Thermoelectric generators (TEGs) have received increasing attention due to their potential to harvest low-grade heat energy (<100 °C) and provide power for the Internet of Things (IoT) and wearable electronic devices. Herein, a wood-based ordered framework is used to fabricate carbon nanotube/poly(3, 4-ethylenedioxythiophene) (CNT/PEDOT) wood aerogel for TEG. The prepared CNT/PEDOT wood aerogel with an anisotropic structure exhibits a low thermal conductivity of 0.17 W m −1 K −1 and is advantageous to develop a sufficient temperature gradient. Meanwhile, CNT/PEDOT composites effectively decouple the relationship between the Seebeck coefficient and electrical conductivity by energy filtering effect to enhance thermoelectric (TE) output properties. The vertical TEG assembled by the CNT/PEDOT wood aerogels reveals an output power of 1.5 μW and a mass-specific power of 15.48 μW g −1 at a temperature difference of 39.4 K. Moreover, the layered structure renders high compressibility and fatigue resistance. The anisotropic structure, high mechanical performance, and rapid thermoelectric response, enabling the TEG based on CNT/PEDOT wood aerogel offer opportunities for continuous power supply to low-power electronic devices.