Graphene fiber is a continuous-phase assembly material composed of graphene sheets stacked in an orderly manner along the axial direction. It is a high-performance, multi-functional new carbon-based fiber first proposed and prepared by the team of Professor Gao Chao of the Department of Polymer Science of Zhejiang University in 2011. With the characteristics of high electrical conductivity, high thermal conductivity, and low density, it has shown attractive prospects in flexible wires, supercapacitors, solar cells, lithium batteries, sensors, etc., and has become a new academic research hotspot. Different from the previous carbon fiber, the building element of graphene fiber is a two-dimensional crystalline graphene with good electrical conductivity, thermal conductivity, mechanical strength, etc. The internal structure of the fiber is three-dimensionally ordered, dense and uniform, and has the potential to convert carbon The performance of the fiber is pushed to a new stage. The main raw material for graphene fiber preparation is graphene oxide, and its assembly methods are diverse. The current mainstream technical method is liquid crystal wet spinning.
In the wet spinning process, the graphene oxide liquid crystal undergoes some processes such as shear flow, solidification forming, and drawing orientation to obtain densely structured graphene oxide fibers. After reduction and graphitization treatments, graphene fibers can be obtained. . The microstructure of the macroscopic graphene fiber assembly strongly depends on the conformation of the graphene sheet. In particular, the random wrinkle conformation of graphene inevitably leads to loose stacking and irregular arrangement, resulting in low crystallinity of graphene fibers. Therefore, how to finely control the conformation of graphene sheets to eliminate random wrinkles is an important challenge to further advance the comprehensive performance of graphene fibers.
In response to this problem, the team of Professor Gao Chao and Professor Xu Zhen of China Zhejiang University and the team of Professor Ma Weigang of Tsinghua University have recently carried out systematic and in-depth research based on the structure regulation of graphene fibers and the relationship between structure and performance. Proposed the "solvent intercalation plasticization stretching crystallization" method, developed a cascade plasticizing spinning technology, which effectively eliminated the wrinkles of the graphene sheets, and promoted the effective arrangement of the approximate crystals of the graphene sheets, and further Advance the comprehensive performance of graphene fibers. The fiber has high mechanical strength (3.4 GPa), electrical conductivity (1.19×106 S/m) and thermal conductivity (1480 W/mK), and initially has the performance advantages of integration of structure and function, showing great industrial applications prospect. Related work was published in Advanced Functional Materials with the title "Highly Crystalline Graphene Fibers with Superior Strength and Conductivities by Plasticization Spinning".