Mechanically robust reduced graphene oxide/bacterial cellulose film obtained via biosynthesis for flexible supercapacitor

Abstract

We report the bio-assembly of holey graphene oxide/bacterial cellulose (HRGO/BC) with a three-dimensional (3D) honeycomb structure. The HRGO/BC composite films could be bended, twisted, knotted and even folded into an ingenious paper plane and yield a high tensile strength of 204 MPa with an elongation of 13.8%. Made of the mechanically robust free-standing HRGO/BC electrodes, the solid-symmetric supercapacitors exhibited a specific capacity of 65.9 F/g at a current density of 0.4 A/g and an energy density of 9.2 W h/kg at a power density of 112.9 W/kg. The excellent electrochemical properties of HRGO/BC electrodes without any other active materials are derived from the continuous 3D honeycomb structure, holey architecture of HRGO, good wettability and excellent mechanical flexibility. Besides, satisfactory mechanical performance and good biocompatibility confer the HRGO/BC promising candidates for multifunctional electronics, especially for wearable and implantable electronic devices. The unique bio-assembly method also provides novel pathway to fabricate integrated 3D honeycomb structure gels or films for medical or/and electrical fields.