Nanocellulose based flexible and highly conductive film and its application in supercapacitors

A novel conductive film with a sandwich structure was successfully prepared from nanofibrillated cellulose (NFC) and carbon nanotubes (CNTs). This film possessed an anisotropic electrical conductivity, and its electrical conductivity and mechanical strength were significantly enhanced. The electrical conductivity of the film was as high as 90.8 S cm⁻¹ and the tensile strength was 60.8 MPa when the CNT loading amount was 19.2 wt%. Based on this unique structure, this flexible conductive film was used to prepare an all-in-one integrated film supercapacitor (IFSC) though a simple electrodeposition method. After the liquid electrolyte penetrated into the composite film, the flexible IFSC possessed a high volumetric capacitance of 11.25 F cm⁻³ and retained stable electrochemical performance under different bending states. Therefore, we believed that the flexible and simply designed NFC based film was a promising candidate for the application in wearable bio-electronics.