Electrodeposited Bi2Te3-carbon black nanocomposites with enhanced thermoelectric and mechanical properties

Abstract

Summary Thermoelectric thin films based on bismuth telluride (Bi2Te3) are widely used for room temperature energy harvesting, but improving electrical, thermal, and mechanical properties simultaneously remains challenging. In this study, Bi2Te3-carbon black nanoparticle nanocomposite films were synthesized by electrodeposition and then systematically characterized. Porous carbon black nanoparticle incorporation increased electrical conductivity to 1,418 S cm−1, more than double that of pristine Bi2Te3, while maintaining competitive Seebeck coefficients, leading to a 15% enhancement in power factor. Thermal conductivity decreased by over 50% due to the enhanced phonon scattering from nanoparticle interfaces and reduced grain size, resulting in a more than 3-fold increase in figure of merit. In addition, the films exhibited improved micromechanical properties, with hardness and elastic modulus increasing by approximately 1.25 and 2 times, respectively. These results demonstrate a scalable strategy to develop mechanically robust, high-performance thermoelectric films for microscale waste-heat energy harvesting.