Graphene‐Skinned Alumina Fiber: Continuously Scalable Fabrication and Its Electrothermal Application in Fiber‐Reinforced Polymer Composites

ABSTRACT Graphene‐skinned alumina fiber (GAF) is a new composite with graphene conformally grown on individual alumina fibers via chemical vapor deposition (CVD). Combining graphene's high conductivity with alumina fiber's strength, GAF shows promising potential for electrothermal applications and structural‐functional integrated composites. Here, it is reported GAF dynamic, continuous, and scalable production using a home‐made roll‐to‐roll (RTR) CVD system, featuring integrated degumming and growth chambers through multi‐stage pressure regulation and nitrogen curtain‐style purging. GAF exhibits excellent flexibility, high tensile strength (>1.1 GPa), and tunable conductivity (40–1260 S m ⁻¹ ). The system ensures intra‐/inter‐batch stability with an annual production capacity of 5100–153 000 m, depending on GAF specifications. GAF exhibits superior electrothermal performance, including broad tunable heating temperature (∼620°C in air, >1200°C in vacuum), ultrafast response (>600°C s ⁻¹ ), and high cycling stability. Furthermore, GAF presents excellent compatibility with the fabrication process of fiber‐reinforced polymer (FRP) composites. By interlaying GAF between glass fiber/epoxy resin unidirectional (UD) prepregs with different orientations, a GAF‐reinforced polymer (GAFRP) composite is developed, showing adequate resin impregnation and uniform electrothermal heating. These findings highlight GAF's potential for structural‐functional integrated FRP composites, particularly in applications such as electrothermal anti‐/de‐icing of aircraft and wind turbine blades, where FRPs are extensively employed.