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The seawater battery is a recent sustainable and cost-effective alternative to replace - or compete with - the lithium-ion battery, as it is composed of the abundant sodium in seawater that functions as charge transfer ions. Read more.
Seawater batteries are not flammable because they use water-based electrolytes
On the other hand, in traditional batteries, the electrolytes are based on chemical solvents that make them volatile and flammable, hence degrading at high voltages.
Traditional batteries have two terminals (besides the electrolytes that carry the electric charge):
Regarding lithium batteries, the electric charge employs lithium ions that move through the electrolyte, going from anode to cathode when charging and vice versa when recharging. That's why they are highly energy-efficient because of their long service life. For this reason, they are being used extensively in consumer electronics, portable or stationary devices, and electric vehicles.
Nonetheless, lithium batteries turn out to be not that good. Why's that?
Lithium batteries face some issues, such as:
Lithium is still a scarce resource because its exploitation is so far recent, which raises its cost.
Lithium's flammability compromises its safety. This is another factor where seawater-based batteries have an advantage.
The demand for seawater batteries is expected to increase because of the following advantages:
Stability efficiency (stable voltage)
Power efficiency (duration)
Voltage efficiency (non-flammable)
Coulombic efficiency (faradaic efficiency or current efficiency), i.e., the ratio of the total charge extracted from the battery to the total charge put into the battery over a full cycle.
An issue with batteries with seawater has been solved.
A concern: lithium dendrites
According to Professor Zhenxing Feng of Oregon University, "The electrolytes in lithium-ion batteries are typically dissolved in organic solvents, which are flammable and often decompose at high operating voltages. There is great concern about their safety because of the growth of lithium dendrites at the electrode-electrolyte interface, which can cause a short between the electrodes."
The researchers declared to Nature Communications that, "the issue was solved after installing a 3D zinc-manganese nanolayer anode, resulting in a stable aqueous battery with a capacity of transferring twice as much charge in comparison to lithium-ion batteries."
According to Xiaonan Shan, co-author of the study and assistant professor of Electrical and Computer Engineering at the University of Houston: "Seawater-based batteries may solve the problem of pollution and fires in electric cars batteries that is concerning consumers nowadays."
Water in abundance
Thanks to a cheaper battery, desalination of the oceans will be more feasible, with a water potential that will allow an endless supply of clean water to residential and agricultural areas, and the so-called “water scarcity” shall no longer exist.
Thus, it’s about time to migrate to an alternative such as the seawater-based battery because according to data provided by the UN, approximately 3 billion people on the planet have limited access to drinking water. If this continues, two out of every three human beings will face water shortages by 2050.
Other seawater battery applications
Life jackets or diving suits
They may come equipped with so-called "wearable marine devices," such as lights and GPS charged with batteries with seawater.
Lighting buoys or monitoring stations
They are usually powered by solar, lithium-ion, or lead-acid batteries. The hazard with these batteries is that toxic substances may leak into the sea. This risk will certainly not happen with seawater batteries.
The US startup Salgenx has developed the first battery using seawater. One of the company's employees told PV Magazine: "This battery allows substantial thermal savings by using a heat pump that measures the coefficient of performance, and can double the savings on the electricity tariff”.