Enzymatic biofuel cells are a subclass of biofuel cells, which employ enzymes to generate energy from renewable sources. In this study, 3-dimensional graphene (3DG)/glucose oxidase (GOx) bio-nanocomposite was fabricated in order to improve enzyme immobilisation and enzyme lifetime with an enhanced electron transfer rate. These enhancements are due to the unique physical properties of 3DG, e.g. high porosity, large surface area, and excellent electrical conductivity. A power density of 164 mu W cm(-2) at 0.4 V was achieved from this enzymatic biofuel cell (EBFC) with an acceptable performance compared to that of the other glucose biofuel cells (GBFCs). The 3DG enhances the enzyme lifetime, decreases enzyme leaking and, due to its good conductivity, facilitates the electron harvest and transfer from the enzyme active site to the electrode. This suggests that 3DG could be used as effective support for enzyme immobilisation on the surface of the electrode in EBFC applications and related areas such as biosensors, bioreactors and implantable biofuel cells. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.