Carbon fibers (CFs) are notable for their lightweight, high strength, and excellent electrical conductivity, making them promising for applications like electrical wiring. However, integrating CFs into copper-based wiring systems faces challenges, particularly regarding conductivity loss in fractured CFs. This article discusses a two-step experiment to enhance electrical and mechanical connection. Electrothermal-induced solvent evaporation (EISE) and meniscus-confined electrochemical deposition (MECD) were identified as effective methods for welding fractured CFs and were successfully implemented in open-air environment. Deposition of carbon nanotubes (CNTs) around the fiber improved conductivity by reducing fiber-tofiber contact resistance and creating a metal-like surface. Microstructural analysis and EDS analysis revealed that the CNT cladding exhibited high density and fewer irregularities and bulges in the joint area. Furthermore, the CNTs were tangled, forming a less organized structure compared to the original CF. In contrast, the Cu cladding exhibited paint-like coverage, significant irregularities, bulges, and cracks but maintained a small thickness. Electrical testing revealed that the average resistance of a single joined fiber decreased to resistance of 11.45 Ω and an electrical resistivity of 2.27 Ω/m, demonstrating improved electrical conductivity. Under optimal conditions, the joined fibers exhibited plastic fracture, and all joints showed improved performance except joint 1.e-g enhanced mechanical strength and stress tolerance.

Two-step experimental analysis of CFsCNTs-Cu for bilayer bonding in electrical wiring
    Abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials
        2.2 Experimental methods
    3 Results and discussion
        3.1 Joining process
        3.2 Macromicrostructure and morphology of joints:
            3.2.1 Macrostructure of joints
            3.2.2 Microstructure and morphology of joints:
    4 Electrical properties
    5 Thermal conductivity
    6 Tensile test and fracture analysis
    7 Conclusion
    Acknowledgements 
    References

• Akhtar Iqbal(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Yang Yang(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Jianwei Dong(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Amir Ali Khan(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Yixuan Zhang(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Yuanbo Bi(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China)
• Zhen Luo(School of Materials Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China, Tianjin Key Laboratory of Advanced Joining Technology, Ministry of Education, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin 300350, China) Corresponding author