High-performance graphene-based carbon fibres prepared at room temperature via domain folding

The assembly of strong graphene into high-performance macroscopic materials has attracted great interest and sustained attention. Thermal treatment has proven effective in improving the performance by restoring pristine graphene lattice from defective graphene oxide. However, the mechanical performance of graphene fibres remains inferior to that of single-layer pristine graphene, primarily due to assembly-induced defects such as microvoids that form during the folding process of two-dimensional sheets to fibre structures. Here we report the room-temperature fabrication of ultrastrong and stiff graphene fibres, which exhibit an average tensile strength of 5.19 GPa and Young's modulus of 529 GPa. We propose a domain-folding strategy to construct highly folded yet densely packed nanotexture, resulting in a tenfold reduction in microvoid volume. The stress distribution within the fibres is homogenized, leading to enhanced mechanical properties. These findings advance the fabrication of carbon fibres and other macroscopic materials assembled from two-dimensional nanosheets, enabling high material quality with reduced energy consumption.