Carbon Nanofibers Cross-Linked and Decorated with Graphene Quantum Dots as Binder-Free Electrodes for Flexible Supercapacitors

Electrical, mechanical, and electrochemical properties are crucial for the materials used as electrodes in a flexible supercapacitor. In this work, we designed and fabricated a novel category of carbon nanofiber mats, in which carbon nanofibers are cross-linked and decorated with graphene quantum dots. The morphology, mechanical property, and electrochemical performance of as-obtained carbon nanofiber mats were characterized systematically. It was illustrated that the carbonized fibrous character, cross-linking structure, and the surface decoration with graphene quantum dots were the key factors determining their mechanical and electrochemical performances as a binder-free electrode for a flexible supercapacitor. The prototype flexible supercapacitors assembled with the as-prepared carbon nanofiber mats showed a manifest power density of 26 kW kg(-1) while the energy density is 6.4 Wh kg(-1), long-term cycling stability, and, pronouncedly, decent mechanical property, which hint at the potential for the practical application of the as-prepared carbon nanofiber mats.