Energy harvesting from water flow through porous reduced graphene oxide networks

Using a syringe pump setup, the authors conducted water flow experiments through porous reduced graphene oxide (rGO). A variety of anions and cations were added to the water to study its effect on energy harvesting. More specifically, the authors performed tests to study effect of: (1) ion concentration in water, (2) type of anion used, (3) type of cation used, and (4) effect of flow rate. The test data indicates that water flow through rGO networks can directly induce drift of charge carriers in graphene and thus generate electricity. Graphene is ideally suited for this application, since it possesses high mobility charge carriers that are ready to be coupled to moving ions present in the flowing fluid. The proposed rGO material could enable harvesting of the ubiquitous, abundant, and renewable mechanical energy of moving water directly to electrical energy. Unlike traditional schemes, the graphene material directly converts the flow energy into electrical energy without the need for moving parts. Such graphene coatings could potentially replace conventional batteries (which are environmentally hazardous) in low-power, low-voltage, and long service-life applications. Once scaled up, this concept offers a potentially transformative approach to energy harvesting, as opposed to incremental advances in current technologies. This work shows how mechanically robust and scalable reduced graphene oxide (rGO) materials can be used to convert the mechanical energy of flowing water into electricity. The proposed rGO material offers unique possibilities for energy harvesting from hitherto untapped renewable sources such as rain, tidal action, waves, ocean currents, river water as well as water flow over boats, submarines, and bridges.image