Fabrication of Light-Weight and Highly Conductive Copper-Carbon Nanotube Core-Shell Fibers Through Interface Design

Metal-carbon nanotube (CNT) hybrid fibers are emerging materials for light-weight conductors that can replace common metallic conductors. One of the main challenges to their development is the poor affinity between CNT and metals. In this work, a new approach for fabrication of CNT/Cu core-shell fibers is demonstrated that outperforms the commercial Cu wires in terms of specific conductivity, ampacity, and strength. By introducing thiol groups to the surface of CNT fibers, a dense Cu coating with enhanced adhesion is obtained. Consequently, CNT/Cu core-shell fibers with specific conductivity of 3.6 x 10(7)S m(-1)and tensile strength of 1 GPa, which is almost five times higher than commercial Cu wires, are produced. Due to strong interaction of thiol functional groups and Cu atoms, the fiber can preserve its integrity and conductivity after >500 fatigue bending cycles. Furthermore, the ampacity of the composite wire reaches to 1.04 x 10(5)A cm(-2), which corresponds to a specific ampacity two times higher than that of commercial Cu wires. The interfacial design between Cu and CNT presented here is versatile and can be implemented in other processing and deposition methods.