Conductive Carbon Black/Graphene Hybrid Fibers with Significantly Enhanced Electrothermal Properties for Fiber Heaters

Graphene-based fibers, being more flexible and lightweight than metal materials, hold significant promise as innovative heat sources for integration into wearable thermal regulation textiles. Nevertheless, the brittleness of pristine RGO (reduced graphene oxide) fibers is unsuitable for practical applications. In this work, CB (conductive carbon black)/RGO hybrid fibers were prepared through wet spinning process and chemical reduction. The structure and properties of the resulted CB/RGO hybrid fibers are systematically investigated and the mechanism underlying these enhancements is discussed in detail. The results show that both the toughness and electrothermal properties of the hybrid fibers are improved as the CB content increases. The highest toughness, elongation, and electrical conductivity are 10.17 MJ m⁻³, 15.71%, and 49.62 S cm⁻¹, respectively. Furthermore, the CB/RGO hybrid fibers can achieve a saturated temperature of approximately 140 ℃ with a low power supply of 5 V, demonstrating efficient electrothermal response, homogeneous temperature distribution, and low operating voltage. The highest heating temperature can exceed 400 °C at 10 V. Meanwhile, the CB/RGO hybrid fibers are capable of functioning normally under bending deformation and demonstrate excellent durability. Overall, as-prepared CB/RGO hybrid fibers are excellent candidates for providing Joule heating in wearable heating fabrics.