Fabrication of high-performance graphene fiber: Structural evolution strategy from a two-step green reduction method

Graphene fibers (GFs) have a bright future in a variety of applications ascribing to their excellent performance. However, strict preparation conditions with extremely high graphitization temperature or toxic chemical reagents severely restrict their extensive implementation. Meanwhile, researchers are seeking easily scalable and eco-friendly GFs production methods. Here, we propose a green two-step reduction strategy involving L-ascorbic acid (LAA) chemical reduction followed by low-temperature annealing for the preparation of high-performance GFs. Benefiting from the elimination of macro-, micro- and nano-scaled defects and recombination of graphene nanosheets, the prepared GFs demonstrated amazing tensile strength of 778.49 MPa, Young's modulus of 92.61 GPa and an outstanding electrical conductivity of 3.2 x 104 4 S m(-1), outperforming most of the chemically reduced GFs. This two-step green reduction strategy provides a new insight for constructing integrated highperformance GFs for sustainable application in many fields.