The important self-assembling, mechanical, and insulating features of GO are derived from oxygen-bearing functional groups, namely hydroxyl, carboxyl, carbonyl, and epoxide moieties [22], which can lead to the formation of hydrophilic regions separated by hydrophobic graphitic domains. The resulting structure may enhance the ion exchange and in particular the transport of protons [23]. Free-standing pure GO membranes have been fabricated and successfully exploited as electrolytes in preliminary tests, showing a higher water uptake compared to Nafion(r)[14; 24] as well as better mechanical properties, lower permeability to hydrogen, and promising in-plane proton conductivity. However, a lower open circuit voltage compared to the one exhibited by Nafion(r)-based devices and poor fuel cell performance have been detected, which may be due to both low through-plane conductivity and high-temperature durability. Therefore, innovative procedures to modify GO with alternative functionalities (e.g., sulfonic groups covalently bonded with the basal plane) are needed to enhance ionic conductivity and both the thermal and structural stability of the material. G and G-related materials also have excellent supporting material properties and the ability to stabilize various electrocatalysts such as metal nanoparticles, metal oxides, and polymers. Such properties, together with a certain electrocatalytic ability for redox reactions, have allowed the use of graphene as a catalytic material for enhanced glucose oxidation in a glucose fuel cell [25]. The aforementioned channeling properties determined by the stacking of graphene layers can also be exploited for the development of hydrovoltaic generators. The latter approach provides a new method for obtaining energy from water that consists of the hydration of the nanochannels, where the overlapping EDLs can exhibit charge selectivity, repelling the co-ions while allowing counter-ions to pass through. This characteristic can enable the generation of electricity via the evaporation of water or directly from moisture. This represents one of the latest extents of graphene-based materials in the field of sustainable energy production [26]. In the case of energy storage purposes, for instance, graphene flakes can be incorporated in metal oxides to be used as electrodes in lithium-ion batteries (LIBs). It has been proven that self-assembled SnO\({}_{2}\)-graphene nanocomposite films can easily have Li-ions inserted into their structure, achieving high specific energy density without relevant charge/discharge degradation [27]. Functionalized graphene sheet-sulfur nanocomposites with a 3D layered structure have also been used for LIBs [28], providing high capacity and good cycling stability. Porous graphene networks prepared via CVD have been assembled in LIBs as high-performance anode materials [29], demonstrating high reversible capacity. Finally, graphene is a valuable candidate for the development of advanced microelectronic components, such as electrochemical sensors. Among others, applications have been reported such as the detection of free chlorine in water using graphene-like carbon-based resistive sensors [30], and, in more general terms, the development of new water quality sensors for the identification of deteriorating water quality [31]. Conceptualization, S.L. ; writing--original draft preparation, S.L. and R.B. ; writing--review and editing, S.L. and R.B. ; supervision, S.L. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. No new data were created in this study. Data sharing is not applicable to this article. The authors declare no conflict of interest.