High surface area graphene foams by chemical vapor deposition

Abstract

Three-dimensional (3D) graphene-based structures combine the unique physical properties of graphene with the opportunity to get high electrochemically available surface area per unit of geometric surface area. Several preparation techniques have been reported to fabricate 3D graphene-based macroscopic structures for energy storage applications such as supercapacitors. Although reaserch has been focused so far on achieving either high specific capacitance or high volumetric capacitance, much less attention has been dedicated to obtain high specific and high volumetric capacitance simultaneously. Here, we present a facile technique to fabricate graphene foams (GF) of high crystal quality with tunable pore size grown by chemical vapor deposition. We exploited porous sacrificial templates prepared by sintering nickel and copper metal powders. Tuning the particle size of the metal powders and the growth temperature allow fine control of the resulting pore size of the 3D graphene-based structures smaller than 1 µm. The as-produced 3D graphene structures provide a high volumetric electric double layer capacitance (165 mF cm −3). High specific capacitance (100 F g −1) is obtained by lowering the number of layers down to single layer graphene. Furthermore, the small pore size increases the stability of these GFs in contrast to the ones that have been grown so far on commercial metal foams. Electrodes based on the as-prepared GFs can be a boost for the development of supercapacitors, where both low volume and mass are required.

Graphene in the Design and Engineering of Next‐Generation Neural Interfaces

“…Furthermore, new promising materials are expected to emerge from the very active research field of the supercapacitors, in which graphene‐based materials exhibiting very large active surface area are being developed achieving very high double layer capacitance. For instance, free standing porous graphene grown by CVD has been reported to exhibit double layer capacitance values exceeding tens of mF cm −2 . The free standing graphene films are obtained by using a porous sacrificial scaffold or by tuning the growth parameters in order to obtain vertical growth of graphene walls.…”

Chemical vapour deposition of freestanding sub-60 nm graphene gyroids

“…Recent literature highlights the promise of such porous, foam-like materials, in particular those derived from graphene, in applications ranging from (opto)electronics, 1,2 artificial skin, 3 electrochemistry, [4][5][6] and catalysis 7 to thermal management, 8 self-cleaning, 9 sorption and filtration, 10 sensors, 11 bio-medical 12 and mechanical metamaterials. 13,14 Among the various synthetic strategies and 3D assembly approaches, 15 chemical vapour deposition (CVD) has emerged as the most viable route not only to grow highly crystalline 2D material films but also to directly grow covalently bonded, continuous 3D networks of these 2D materials.…”

“…Transition metal templates are particularly promising, with catalytic properties that enable the synthesis of highly crystalline graphene at relatively low temperatures. 17,18 While numerous methods to create suitable 3D metal templates have been demonstrated, ranging from commercial metal foams 1 and the sintering of metal powders 4,5 to 3D printing 19 and two-photon lithography, 20 the bottleneck remains 3D template control and accessible sizes/resolution. Typical metal foams have pore diameters of the order of 100 µm, 1 and over such large sizes 3D structures based on mono-or few-(<20) layer graphene are not sufficiently mechanically stable, i.e.…”

“…The smallest pore sizes demonstrated to date are of the order of 1 µm. 4,20 More recently, nano-porous zeolites decorated with Lanthanum have been used as a template to create carbon frameworks, albeit not fully graphitised. 7 Further, computational modelling has recently highlighted the potentially exceptional properties of periodic gyroid graphene structures.…”

MXene-based 3D porous macrostructures for electrochemical energy storage

“…As highlighted by Verger et al [10], it is important to note that none of these methods were able to produce single layer materials. Synthesis of MXenes by CVD and other bottom-up approaches are still very much unexplored, however, as one of the most common techniques of building high quality 3D graphene scaffolds [2,80], these works present promising potential for the processing of high-quality 3D MXene architectures for specific applications.…”