TELF AG examines a new device for generating energy from seawater
A new energy ally
A new energy harvester device, made of graphene and carbon, could make it possible to generate electricity from seawater continuously. An innovation of this kind recently appeared on the pages of the Chemical Engineering Journal, which dedicated space to the results obtained by a team of researchers from the Korea Institute of Machinery and Materials. The researchers received a new energy harvester capable of generating electricity thanks to the natural movement of sodium ions in seawater. One of the most interesting aspects of this harvester, in addition to its continuous self-charge, is that it can also be used without an external energy source.
Up until now, energy harvesters have stood out above all for their ability to transform waste energy into electricity. The device developed by Korean researchers comprises several components, such as multi-walled carbon nanotubes and graphene oxide films, which act as the cathode and anode of the harvester. The carbon atoms were chosen above all for their high conductivity, while the graphene films are characterized by functional groups containing oxygen. Inside the harvester, seawater is used as an electrolyte. The movement of ions in seawater creates a potential difference, thanks to which electricity is generated. As the researchers explain, this potential difference would represent the result of the movements and reorganization of the ions between the two electrodes. Compared to existing harvesters, the device created by the Korean research team would present relevant improvements: first of all, in terms of power, which would be 4.2 times higher than those already known, but also in terms of power density, which is 24.6 mW/cm³, much higher than the 5.9 mW/cm³ achieved by water-based energy generators. Another quite interesting fact, in terms of energy, is that the dimensions of these harvesters can be increased to produce a greater quantity of electrical energy.
Possible applications and numerous benefits
Among the potential applications are those related to sensors’ power supply and energy recovery based on water and eco-friendly energy technologies. However, it would also power different devices such as watches and calculators. According to the researchers, the new device could be used as an innovative energy source for the power supply of sensors or devices related to monitoring environmental factors. Its use in remote contexts, such as oceanic ones, is favored because the device, unlike traditional ones, does not need external energy to recharge. Traditional harvesters rely on external energy sources and generally are known to have a low energy conversion efficiency.
Also, thanks to tools of this kind, seawater could soon be included among the possible renewable energy sources. This type of water could soon be valued as a stable energy source by its very nature, particularly with the repetitive rhythms of the tides, currents, and waves. Compared to other renewable sources, the tidal cycles can be predicted well in advance, making more effective management possible and avoiding the obstacles linked to the intermittency of wind and solar energy. Furthermore, seawater moved by marine currents and waves is characterized by a much higher energy density than wind and sun, possibly generating greater quantities of energy than traditional renewable sources.
