Deep eutectic solvent assisted preparation of cellulose nanofibers and graphene composite films for supercapacitors

Abstract

Flexible cellulose nanofiber-modified graphene composite has been prepared using rice husk and graphite as the feedstocks. First, cellulose nanofibers (CNFs) were obtained from designated rice husk by green choline hydroxide (ChOH) and L-necropine hydrochloride deep eutectic solvent (DES), which can efficiently promote the dispersion of graphene oxide and relatively reduced graphene oxide (rGO) to form rGO/CNF composite membranes. The composite film shows good bending and low resistance to charge transfer. Electrochemical testing studies reveal that the as-prepared rGO/CNF composite membranes can work as an efficient electrode for supercapacitors, and it shows a high area-specific capacitance (382 mF cm⁻² when the current density is 1 mA cm⁻²) and good cycle stability (6% capacitance loss over 3000 cycles at 10 mA cm⁻²). The rGO/CNF composite has potential applications as electrodes for flexible supercapacitors.