The Interface Anchoring Effect of Nickel Nanoparticles on Carbon Nanotube/Nickel/Copper Composite Wires with Ultra-High Conductivity and Current-Carrying Capacity

Abstract

Carbon nanotube fibers (CNTFs) are regarded as one of the most promising new conductor materials with light weight, high strength and high electrical conductivity. Due to the structural defects, the inter-tube contact resistance and the misalignment within the CNTFs, the actual electrical conductivity is far below the theoretical expectation. A metal/CNTF composite conductor material has been developed to combine the advantages of light weight and high strength of CNTFs and the high electrical conductivity of metals. However, the poor interfacial wettability and weak orbital matching between CNT and metal result in a large interfacial resistance of metal/CNTFs, which cannot take full advantages of the composite conductors. Here, we report a novel improvement method for the interfacial properties of the copper/CNTF composite wire. Nickel nanoparticles of certain size and density are introduced on the surface of CNTFs as interface anchor points, and then the CNTF/nickel/copper composite wires are prepared by electrochemical deposition. The introduction of nickel nanoparticles significantly improves the electrochemical activity and flatness of the surface of CNTFs, and endows the fibers with stronger interfacial bonding strength with copper. After annealing, the CNTF/nickel/copper composite wires obtain excellent mechanical and electrical properties. The mechanical tensile strength of the composite wires reaches 1.1 GPa, the electrical conductivity reaches 2.0 × 107 S/m (68% IACS), the specific electrical conductivity is 5.5 kS·m2/kg, and the current-carrying capacity is 1.9×106 A/cm2, which is two orders of magnitude higher than that of copper.

Keywords: carbon nanotube fiber, Cu/CNT composite, Conductivity, current-carrying capacity