Thermoelectric Properties of Polyaniline/Bismuth Antimony Telluride Composite Materials Prepared via Mechanical Mixing

Abstract

Organic-based thermoelectric composites are highly promising for low-temperature heat-to-electrical energy conversion applications due to their low toxicity, cost-effectiveness, facile synthesis and easy processing. Potential applications of such materials include, among others, low-temperature waste heat recovery and body heat use, such as wearable thermoelectric devices and sensors. Due to the lack of studies on organic (matrix)–inorganic (additive) thermoelectric composites prepared via mechanical mixing with respect to the processing parameters and thermoelectric performance, this work aims to contribute in this direction. More precisely, composite pellets were prepared starting from polyaniline (PANI)/bismuth antimony telluride mixed powders using a mechanical press. The processing parameters investigated included temperature, pressure and processing time, along with the inorganic additive (bismuth antimony telluride) content introduced within the composites. The experimental data revealed that the processing temperature and the additive content had the most significant effect, since their increase led to an enhancement in the composites’ thermoelectric performance. The optimal ZT (2.93 × 10−3) recorded at 130 °C corresponded to PANI-BST composites with a 30 wt.% BST content, prepared at a processing temperature of 80 °C, a processing time of 75 min and under 2 tons of pressure.