Preparation, properties, and application exploration of electrolytic Cu-CNTs composite foils

Abstract

Carbon nanotubes (CNTs) reinforced Cu matrix composites are a hotspot of current research, but the majority of them are bulk samples by sintered or die-cast formed. There are few works on preparing large-size and ultrathin Cu-CNTs composite foils (CCFs) by electrodeposition with the process and environment imitating industrial production of electrolytic Cu foils, and investigating the properties and application potential of CCFs. Herein, large-sized and ultrathin CCFs were prepared via electrodeposition with a high current density (0.5 A/cm²), a short deposition time (120 s), and a large volume of circulating electrolyte (70 L). The microstructure, mechanical properties, surface roughness, and resistivity of the CCFs were investigated. The foils with CNTs of 50 mg/L exhibited the best overall performance, with a tensile strength of 550 MPa (25 °C) and elongations of 4.9 % (25 °C) and 13.2 % (180 °C), representing improvements of 66.7 %, 88.5 %, and 135.7 % respectively, compared with that of the pure Cu foil. Load transfer and the Orowan mechanism together strengthened the CCFs. The elongation of CCFs demonstrated stability in response to the content of CNTs both at room and at elevated temperatures, which may be attributed to the “pulled out” effect of CNTs. The potential applications of CCFs in printed circuit boards and lithium-ion batteries were explored, the use of CNTs may lead to adverse effects such as surface discoloration, pinholes, and compromised soldering reliability. The CCFs with a low dosage of CNTs showed promising overall performance, indicating a viable pathway for future research.