Nanocellulose-based electrodes and separator toward sustainable and flexible all-solid-state supercapacitor

Nanocellulose, as the most abundant natural nanomaterial with sustainability, biodegradability, and excellent mechanical properties, has been widely applied in modern electronic systems, particularly, in the flexible electrochemical energy storage devices. Herein, a reduced graphene oxide (RGO)/cellulose nanocrystal/cellulose nanofiber (RCC) composite membrane was prepared by using a one-pot method. Compared to the pure RGO membranes, the RCC composite membranes exhibited better mechanical properties and hydrophilicity. Furthermore, due to the synergistic effect of nanocellulose and RGO sheets, the RCC composite membrane exhibited a specific capacitance as high as 171.3 F center dot cm(-3). Consequently, a nanocellulose-based symmetric flexible all-solid-state supercapacitor (FASC) was constructed, in which two RCC composite membranes served as elec-trodes and a porous cellulose nanofiber membrane acted as separator. This fabricated FASC demonstrated a high volumetric specific capacitance of 164.3 F center dot cm(-3) and a satisfactory energy density of 3.7 mW center dot h center dot cm(-3), which exceeded that of 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.

Automated summary

A reduced graphene oxide (RGO)/cellulose nanocrystal/cellulose nanofiber (RCC) composite membrane was prepared using a one-pot method, which exhibited improved mechanical properties and hydrophilicity compared to pure RGO membranes. The RCC composite membrane showed a specific capacitance as high as 171.3 F cm(-3) due to the synergistic effect of nanocellulose and RGO sheets. A nanocellulose-based symmetric flexible all-solid-state supercapacitor (FASC) constructed using this composite membrane demonstrated a high volumetric specific capacitance of 164.3 F cm(-3) and a satisfactory energy density of 3.7 mW h cm(-3), surpassing many other reported flexible supercapacitors. This work could pave the way for the design of next-generation nanocellulose-based sustainable and flexible energy storage devices.