Scalable fiber-skeleton-reinforced graphene-assembled films enabling wash-durable wearable heating

Wearable heating is a compelling solution for personal thermal management (PTM), enabling localized, energy-efficient warming. Graphene-assembled films (GAFs) possess outstanding flexibility and electrothermal performance, yet their practical application is hindered by inherent brittleness and low resistance to crack propagation, leading to premature mechanical failure and performance drift. Herein, we report a scalable fiber-skeleton-reinforcing strategy for toughening GAFs that addresses this durability bottleneck. Polyacrylonitrile fibers are introduced into the precursor suspension and, after high-temperature treatment, transform into graphitized carbon fibers that stitch graphene layers into a continuous load-bearing network. This fiber-reinforced architecture increases tensile toughness by approximately 90% while preserving high electrical conductivity (0.4×10⁶ S/m) and thermal conductivity [1.0×10³ W/(m·K)]. Integrated into a winter jacket, the film delivers rapid, low-voltage wearable heating, reaching 40.8 °C within 30 s at only 5 V. Critically, the heating performance remains stable after 60 machine-washing cycles, demonstrating a practical pathway toward mass-produced, wash-durable graphene heaters for advanced PTM.