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

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.