Nanocellulose-Based Electrodes and Separator Toward Sustainable and Flexible All-Solid-State Supercapacitor

Abstract

Nanocellulose, as the most abundant natural nanomaterial with sustainability, biodegradability, and excellent mechanical properties, has been widely applied in modern electronic systems, particularly the flexible electrochemical energy storage devices. Herein, we constructed a nanocellulose-based symmetric flexible all-solid-state supercapacitor (FASC), in which two reduced graphene oxide/cellulose nanocrystal/cellulose nanofiber (RCC) composite membranes served as electrodes and a porous CNF membrane acted as separator. The RCC composite membranes, which were prepared using a facile one-pot method followed by chemical reduction of graphene oxide to reduced graphene oxide, possessed excellent mechanical properties and hydrophilicity. Consequently, this fabricated FASC demonstrated a high volumetric specific capacitance of 164.3 F·cm -3 , a high capacitance retention of 71.1% after 1000 cycles, and a satisfactory energy density of 3.7 mW·h·cm -3 , which exceeded many other FASCs ever reported. This work may open a new avenue in design of next-generation nanocellulose based, sustainable and flexible energy storage device.

Keywords: cellulose nanocrystal, cellulose nanofiber, reduced graphene oxide, high energy density, flexible supercapacitor.