Electrical conductivity, thermal transport, and tensile properties of carbon nanotube/silver composite fibers

This study combines liquid-crystalline spinning with hydrogen annealing to fabricate highly oriented single-walled carbon nanotube (SWCNT)/silver composite fibers (Ag-SWCNTFs). SWCNT/Ag2S composite fibers (Ag2S-SWCNTFs) containing different proportions of Ag2S were first prepared by liquid-crystalline spinning, followed by hydrogen annealing to reduce Ag2S in situ and form silver fibers within the CNTFs. SEM and XAFS analyses confirmed the formation of silver fibers within the highly oriented Ag-SWCNTFs. The effects of Ag2S content and annealing conditions on the microstructure, electrical conductivity, thermal conductivity, and mechanical properties were systematically investigated. After hydrogen annealing at 600 °C for 30 h, the composite fibers containing 30 wt% Ag2S exhibited a longitudinal electrical conductivity of 6.23 × 105 S cm−1 and a thermal conductivity of 442 W m−1 K−1, while maintaining a specific strength of 3.5 N/tex. The enhanced electrical conductivity is associated with the incorporation of silver fibers into the CNT network, whereas the improvement in thermal conductivity is attributed to the combined contributions of silver and CNTs to heat transport. This approach enables the simultaneous enhancement of electrical and thermal conductivity while maintaining mechanical performance, highlighting its potential for high-performance conductors, thermal management materials, and flexible electronic devices.