Compressible cellulose nanofibrils/reduced graphene oxide composite carbon aerogel for solid-state supercapacitor

The investigation of electrodes with excellent electrochemical and mechanical properties is the key to achieve flexible supercapacitors. Herein, a nanocellulose-based carbon aerogel with 3D porous structure for high performance composite electrodes of compressible supercapacitors is proposed. Cellulose nanofibril (CNF) is used to construct the elastic network structure of carbon aerogel. Graphene oxide (GO) mainly acted as the skeleton in the carbon aerogel to prevent shrinkage of nanocellulose during the carbonization process. The as-prepared carbon aerogel displayed outstanding compressibility (undergoing a strain of 80%) and elasticity (96% stress retention after 2000 compressive cycles at 30% strain). Furthermore, highly flexible and solid-state supercapacitors using cellulose nanofibrils/reduced graphene oxide (CNF/RGO) carbon aerogels as electrodes are fabricated. Due to the porous structure and outstanding mechanical properties of the electrodes, the assembled supercapacitors exhibit excellent electrochemical properties with good cycle stability (82% retention after 5000 cycles). Therefore, this research provides a simple and effective method for fabricating well-designed structured electrodes for compressive energy storage devices.Graphic Abstract