A spinneret as the key component for surface-porous graphene fibers in high energy density micro-supercapacitors

A metal needle spinneret was found to be the key component to synthesize neat graphene fibers with a porous surface in the wet spinning process. Flexible solid-state micro-supercapacitors (micro-SCs) based on the neat graphene fibers were then designed and fabricated. The as-prepared graphene fibers with an impressive specific surface area up to 839 m(2) g(-1) achieved an excellent specific capacitance of 228 mF cm(-2) at 39.7 mu A cm(-2). The assembled micro-SCs exhibited excellent performance such as high energy densities of 7.9 mu W h cm(-2) (or 4.0 mW h cm(-3)) approaching those of lithium thin film batteries and excellent long life stability. This research opens the door to the synthesis of surface-porous neat graphene fibers and these fibers are promising as electrode materials in high-performance micro-SCs.