Wet Spinning Assembled Graphene Fiber: Processing, Structure, Property, and Smart Applications

Graphene fiber, a macroscopic one-dimensional material formed by assembling elementary graphene flakes, has emerged in response to the increasing demand for multifunctional or even smart fibers. Based on the astonishing properties of graphene building blocks, graphene fiber presents a series of attractive features, such as superior mechanical strength and electronic conductivity, light-weight, and efficient thermal conductivity. As a result, graphene fiber exhibits broad prospects for application in ultralight cables for aerospace, wearable energy storage devices, biosensors, and neuroelectronics. graphene fiber may provide a critical breakthrough for realizing multi-functional fibers or even smart textiles. Since it was first prepared in 2011, numerous fabrication techniques have been developed to assemble graphene fiber, such as wet spinning, space-confined hydrothermal assembly, film twisting approaches, and template-assisted chemical vapor deposition. Among various graphene fiber preparation approaches, wet spinning has great application potential, as it affords the best mechanical strength and electrical conductivity of the prepared graphene fiber, along with great compatibility with the commercialized wet spinning technique. Therefore, the wet spinning approach has attracted extensive attention for batch production of high-performance graphene fiber. Herein, we introduce the pivotal steps of the wet spinning preparation of graphene fiber, with focus on summarizing the detailed strategies for enhancing the fiber properties and we also discuss the relationship between the structure and assembly approaches. The wet spinning technology for assembling graphene fiber includes a series of critical steps, such as preparation of the spinning liquid, bath coagulation, spinneret design, and post-treatment process. These procedures may have a significant influence on the micro-, meso-, and macro-structure of the final prepared graphene fiber. We also discuss the fundamental relationship between the typical properties of graphene fibers and their hierarchical structures, such as the in-planar structure of graphene sheets, aggregation structure of graphene flakes, and the macrostructure or morphology of graphene fiber. The recent advances in graphene fiber-based smart fibers and fabric applications are also analyzed, highlighting possible strategies for promoting structural-functional integrated applications. Finally, the current challenges and possible approaches for further improving the mechanical and electric properties of graphene fiber are presented. This review can be briefly divided into three parts: (1) details of the wet spinning process and its specific influence on the structural features of graphene fiber, (2) characteristics of current graphene fibers and promising strategies for enhancing the properties, (3) latest studies of graphene fiber applications and perspectives for future application.

Automated summary

Graphene fiber, composed of graphene flakes, possesses excellent mechanical strength and electrical conductivity. It has broad applications in aerospace, energy storage, biosensors, and neuroelectronics. Wet spinning is an effective method for fabricating graphene fiber.