Building a battery isn’t terribly complicated: All you need is a cathode, an anode, and an electrolyte that transmits ions between them. In a quest to develop a sustainable alternative to lithium, a team of scientists from South Korea is looking to the sea for some of those components, inhabitat reports.

In their study published in the journal ACS Applied Materials & Interfaces, the nine researchers from Ulsan National Institute of Science and Technology (UNIST) illustrate the science behind their seawater battery. Here the saltwater serves as a catholyte, which acts as both the electron-collecting cathode and the ion-transporting electrolyte simultaneously. Their invention (technically a sodium-air battery) depends on sodium-ion-rich saltwater to function, and with access to the ocean, it’s able to provide a constant charge.

The sustainable nature of seawater makes it the perfect contrast to lithium, which is used in the batteries that power our iPhones and electric cars. Lithium needs to be mined from the earth, which can have damaging effects on entire landscapes. Seawater, on the other hand, is something we have in excess.

The seawater battery still needs some fine-tuning before it’s ready to compete with lithium on the commercial market (UNIST’s battery produces an average of 2.7 volts compared to the average 3.6 to four volts discharged by a lithium-ion battery). But the potential for a day when ocean-powered batteries become mainstream is there.

[h/t inhabitat]