Bioinspired strong and rigid fusion-spun graphene fibers for harsh robotics

High-performance fibers with the merits of lightweight and high strength are indispensable to modern industry. However, the performance trade-off between tensile strength and bending rigidity limits their more applicational possibilities as structural materials. Inspired by the hierarchical assembly of biomaterials, we exploit graphene fibers through multiscale fusion spinning of gel fiber bundles with an unprecedented synergy of high tensile strength of 3.0 gigapascal and bending rigidity reaching 1.6 × 10⁶ newtons per square micrometer for a 100-micrometer-thick fiber (more than 10⁴ times higher than Kevlar fibers). Continuous fusion-induced defect suppression produces thick fibers with homogeneous ordering and performance. These fibers also exhibit exceptional thermal and electrical conductivities, showing their potential as structure-function integrated materials. The fibers are used as wing veins, feet, or claws of robots, resisting extreme conditions including wind speed from 0 to 7 Beaufort scale, pH from 0 to 14, and temperature from 4 to 2000 kelvin. These results promise structural materials design, bionic functions, and robotics in harsh environments.