The capacitive performance of three-dimensional (3D) freestanding graphene macroporous material (3D-G) fabricated via a chemical vapour deposition (CVD) methodology is comprehensively investigated a potential supercapacitor material, without any mechanical support, for the first time. The capacitive performance of the 3D-G material are investigated within both aqueous electrolytic media and ionic liquids. The 3D-G exhibits a capacitance of 266 µF when charged at 16.6 µA g -1 in an aqueous

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... olyte; a significant improvement over a freestanding 3D reticulated vitreous carbon (3D-RVC) macroporous alternative in the same electrolyte and conditions which exhibits a value of only 20 µF. Further improvements are demonstrated by utilising ionic liquids as the electrolytic component. [C4MIM][BF4] demonstrated the capacitance across each current analysed, demonstrating values from 287 µF up to 636 µF for the current range 6.66 mA g -1 down to 16.6 µA g -1 and a specific energy density of 40.94 W h kg -1 and a power density of 29.33 kW kg -1 . Through varying the ionic liquid we demonstrate that the capacitance of the 3D-G is influenced by the ion mobility and the molecular mass of the electrolyte which has a profound effect upon the formation of the EDLC; higher molecular weights develop the charge double layer slower, resulting in a slightly poorer capacitive performance. The 3D-G exhibits a significant capacitive improvement over that of RVC and a nickel macropourous control (which is used as the CVD growth substrate) exhibiting remarkably high energy and power densities. 3 Broader Context Supercapacitors are electrochemical energy storage systems that are finding applications in many technological fields. While the energy density of the supercapacitor is much higher than that of a conventional dielectric capacitor, it is still lower than that of batteries and fuel cells. The evolution of nanostructured materials has offered opportunities for the development of high-energy density supercapacitors. Despite this, nanomaterials are predominantly characterised as deposited on an existing electrode material as an additive or enhancement, or on a substrate, which provides the mechanical support required for the nanomaterial. Consequently, the development of an energy storage platform that applies such advanced developed materials is greatly hindered by the requirement of integrating the substrate into the final device specification and manufacture. Here, we demonstrate an approach to fabricate a symmetric electrode supercapacitor utilising a freestanding nanomaterial for the first time. A freestanding graphene macrostructure is developed to utilised the enhanced performance of the nanomaterial, without the compromise of using heavier and low performance substrates and mechanical support; the graphene macrostructure exhibits outstanding cell performance (energy and power density) over carbon macrostructure equivalents. The present work will generate a broad range of interest for those who work on graphene-based materials and energy storage devices. 4