Electrical and thermal conductivity improvement of carbon nanotube and silver composites

Abstract

Carbon nanotubes (CNTs) were mixed with silver particles and nanowires in an effort to produce lightweight conductors of Ag/CNT composites. Silver nanostructures composites with CNTs were achieved through sonication, filtration and infusion processes. Uniform dispersion of silver nanostructures in the composite samples was achieved using different amounts of silver (Ag), and then the samples were characterized under scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Both electrical and thermal conductivities were improved by increasing the amount of silver particles and sizes. The samples with silver nanowires (AgNWs) with high aspect ratios had a lower percolation threshold and achieved higher electrical and in-plane thermal conductivity of 1.3 × 104 S/cm and 126 W/mK at 9 vol % of Ag content, respectively, at room temperature. Temperature dependence of resistivity of the resultant CNT/Ag composites can be described using a heterogeneous model with metallic and non-metallic terms. The CNT/AgNW composites showed the dominant metallic transport mechanism down to 17 K. Also, a high in-plane thermal conductivity of the AgNW samples demonstrated good thermal dissipation. The resultant Ag/CNT composites conductors demonstrated low density and high transport properties for potential engineering applications.