Graphene-based technologies for energy applications, challenges and perspectives

Abstract

Here we report on technology developments implemented into the Graphene Flagship European project for the integration of graphene and graphene-related materials (GRMs) into energy application devices. Many of the technologies investigated so far aim at producing composite materials associating graphene or GRMs with either metal or semiconducting nanocrystals or other carbon nanostructures (e.g., CNT, graphite). These composites can be used favourably as hydrogen storage materials or solar cell absorbers. They can also provide better performing electrodes for fuel cells, batteries, or supercapacitors. For photovoltaic (PV) electrodes, where thin layers and interface engineering are required, surface technologies are preferred. We are using conventional vacuum processes to integrate graphene as well as radically new approaches based on laser irradiation strategies. For each application, the potential of implemented technologies is then presented on the basis of selected experimental and modelling results. It is shown in particular how some of these technologies can maximize the benefit taken from GRM integration. The technical challenges still to be addressed are highlighted and perspectives derived from the running works emphasized.

Morphing Graphene-Based Systems for Applications: Perspectives from Simulations

“…Controlling interaction of graphene with atomic or molecular species has also a direct use in energy applications: graphene has a huge surface-to-mass ratio, therefore it would be in principle an ideal candidate not only for gas (mainly hydrogen) storage applications, but also for supercapacitors and batteries [57]. In addition, reactivity control is a key step for building 3D networks with organic interlayer spacers.…”

State-of-the-Art Electronic Devices Based on Graphene

“…Numerous studies have been conducted to describe the advances achieved by researchers in energy applications using graphene as an active material [59,60]. Mechanical properties such as mechanical resistance and flexibility can be exploited to design bendable, foldable and/or stretchable devices for flexible energy conversion and storage.…”

“…Mechanical properties such as mechanical resistance and flexibility can be exploited to design bendable, foldable and/or stretchable devices for flexible energy conversion and storage. The main applications of the graphene are photovoltaic devices (solar cells) [60], fuel cells [61], nanogenerators [62], supercapacitors [59] and batteries [58][59][60]63]. These devices are potentially applied in roll-up displays, electronic papers, touch screens, active radiofrequency identification tags, wearable sensors and implantable medical devices, which form part of the applications of wearable and portable electronics.…”

“…Graphene has been proposed as an ideal material to replace transparently and conductive oxides such as zinc oxide (ZnO), indium-tin oxide (ITO) and tin dioxide (SnO 2 ). However, further studies must be carried out for fulfilling such technological requirements [59]. A Schottky junction solar cell with modified graphene films and silicon pillar arrays provide a conversion efficiency of up to 7.7%.…”

“…Graphene has been used extensively as a material for electrodes used in supercapacitors. Efficient supercapacitors or hydrogen storage materials can exploit graphene, thanks to its high specific surface area (SSA) with theoretical values of 5000 m 2 /g (considering the incorporation of holes into graphene), although the best state of the art is of only 3000 m 2 /g [59,64]. Graphene achieves an ideal capacitance of 200-500 F/g which depends on the surface area, pore size (both previous qualities are improved by chemical activation treated with alkali) and the electrical conductivity of the material (chemical doping to increase the carrier concentration) [22].…”