Highly Thermally Conductive yet Structurally Stable Graphene/Ceramic Fiber for Extreme Thermal Protection

ABSTRACT Carbon fiber (CF) holds promise for preparing thermal protection materials for extreme high‐temperature applications. However, the performance of typical thermal protection materials composed of CF and ceramic coating remains inadequate mainly because of the low thermal conductivity and weak interfacial stability. Here, starting from the graphene fiber (GF) with thermal conductivity of ∼1200 W m −1 K −1 , we report highly thermally conductive and structurally stable graphene/titanium carbide fiber (GTF) with well‐defined core–shell structure via a one‐step molten salt synthesis approach. With an optimal shell thickness of 1 µm, the single GTF exhibits a thermal conductivity of 745 W m −1 K −1 and excellent thermal shock resistance without interfacial failure, ensuring its durability for long‐term service in extreme conditions. Moreover, GTF woven exhibits excellent ablation resistance. The mass ablation rate is as low as 0.3 mg s −1 after exposure to oxyhydrogen flame at 2200°C. The excellent performance is attributed to the intrinsic high thermal conductivity of GF for rapid thermal dissipation and the full‐scale fractal‐like interlocking interfaces between the GF and carbide coating for sustaining local interface stress. This work paves the way for GF/ceramic composites as next‐generation dredging thermal protection materials to satisfy extreme heat flux management and structural integrity.