Interface Engineered Spinning of Carbon Nanotube Fiber for Fabrication of Unprecedentedly High-Performance Cu/Carbon Nanotube Fibers

Electroplating copper (Cu) on carbon nanotube fiber (CNTF) is a promising approach to fabricate a Cu/CNTF as a next-generation electrical wire based on the electrical properties of Cu and light weight, high mechanical, and thermal properties of CNTF. However, the mechanical and electrical properties of Cu/CNTFs are inferior to those of Cu wires owing to low interfacial shear strength and high contact resistance. Herein, 2-pyrene imine thiol (PIT), having strong affinity to both Cu and CNTF, is incorporated into liquid crystalline (LC) dope of CNTF for interface engineered spinning. The resulting PIT-CNTFs are harnessed for Cu electroplating with accelerator and suppressor to form the conformal contact between Cu and CNTF. The Cu/PIT-CNTF exhibits unprecedentedly high tensile strength (3.97 GPa), electrical and specific electrical conductivity (1.07 × 10⁸ S·m⁻¹ and 1.79 × 10⁴ S·m²·kg⁻¹), and current carrying capacity (9.41 × 10⁵ A·cm⁻²), which are 14.18-, 1.88-, 2.89-, and 5.80-fold higher than those of Cu wire, respectively. Based on the properties, the Cu/PIT-CNTF is used as an electrical wire for earphone, recharger, and lighting bulb, and its electrical properties are more stable under high temperature, repeated bending cycles, corrosion, and alternating current than Cu wire.