Facile synthesis and enhanced properties of acetylene carbon black conductive fillers in PVDF/bismuth telluride-based flexible thermoelectric materials

Abstract

The development of flexible thermoelectric materials holds immense potential for applications in wearable electronics and energy harvesting devices. In this study, a ternary composite system comprising polyvinylidene fluoride (PVDF), acetylene carbon black (ACB), and Sb1.5Bi0.5Te3 (Bi-Te) was designed and investigated. The inherently insulating nature of PVDF was effectively transformed by incorporating ACB as a conductive filler, enabling the formation of percolation networks crucial for electron transport. A percolated threshold of ACB loading at ∼23 wt. % of PVDF provided a balance between electrical conductivity (∼4.0 S/cm) and mechanical flexibility. The addition of Bi-Te to the PVDF/ACB matrix significantly enhanced the Seebeck coefficient, which increased from 12 μV/K for the binary composite to 72 μV/K for the ternary composite with Bi-Te. This enhancement resulted in a peak power factor (PF) of 1.15 μW/mK2. This study underscores the potential of PVDF/ACB/Bi-Te composites as flexible thermoelectric materials, combining moderate thermoelectric performance with excellent mechanical properties.