High Thermoelectric Performance Carbon Nanotube/Polycaprolactone Composites for Sustainable Energy Harvesting

Harvesting electricity with high-performance biodegradable thermoelectric (TE) composites is a sustainable and promising approach that addresses the environmental concerns brought from the conventional thermoelectric devices. In this work, a TE composite based on single-walled carbon nanotubes (SWCNT) is reported and biodegradable polycaprolactone (PCL) with significantly improved TE performance, achieving a significant improved power factor of 439 µW m^-1 K^-2 at 90 wt.% SWCNT loading. The good surface compatibility and interfacial interaction between PCL and SWCNT are conducive to the formation of abundant PCL-SWCNT junctions, enabling an efficient energy filtering effect that significantly enhances the Seebeck coefficient to 40.8 µV K^-1 at SWCNT content of 90 wt.%. Meanwhile, minimal charge tunneling hindrance is allowed to across thin PCL layers, thereby maintaining a high electrical conductivity of 2635 S cm^-1. Subsequently, a flexible TE device assembled from the SWCNT/PCL composite films exhibits a power density of 1.50 W m^-2 at a temperature difference of 30.8 K, demonstrating great potential for high-performance and sustainable thermoelectric energy harvesting.