Macroscopic One-Dimensional Graphene Materials: Preparations And Applications

Macroscopic one-dimensional graphene materials including graphene fibers (GFs) andgraphene microtubes have been studied in this work. We have prepared and explored itsapplications by hydrothermal synthesis and electrochemical reduction method. GFs possessthe features like light weight, high electrical conductivity, mechanical flexibility for textiles,but the corresponding surface areas is low due to their compact structures. Herein, wedesigned and fabricated a unique all graphene core-sheath fiber, in which a core of GF iscovered with a sheath of3D porous network-like graphene framework. This hierarchicalhybrid structure is denoted as GF@3D-G. The high electronic conduction of the coregraphene fiber and the highly exposed surface areas of3D graphene network are wellcombined within the GF@3D-G. In a three-electrode system, graphene fiber acted asworking electrode, Pt wire and Ag/AgCl (3M KCl) were used as counter and referenceelectrodes, respectively, GO aqueous suspension containing0.1M lithium perchlorate asthe electrolyte solution. During the electrolyzing process, GO sheets were reduced intoconductive graphene and self-assembled into3D interpenetrating networks on GF electrodeunder the driving force of electric field. The electrochemical performance of GF@3D-G ismuch better than pure GF according to the cyclic voltammetry (CV) response in athree-electrode electrochemical cell. The fiber supercapacitors comprise two intertwinedelectrodes which are solidified in the H2SO4-polyvinyl alcohol (PVA) gel electrolyte forformation of an all-solid-state fiber supercapacitor. The assembled fiber supercapacitor ofGF@3D-G is highly flexible, which can be conveniently woven into a textile for wearableelectronics, and can also be managed to spring supercapacitor with highly compressible andstretchable properties. We also prepared graphene microtubes by hydrothermal process. Inorder to increase the surface areas, three dimensional graphene were assembled on theouter-wall and inner-wall of the graphene microtube by electrochemical reduction method.We investigated the capacitance of this material. The applications in separation andpurification are to be furture explored.