Green, saltwater

The lithium-ion batteries that power much of the modern world may be our best solution currently, but scientists continue to experiment with their makeup in pursuit of devices that are safer and less environmentally costly (among other desirable attributes). A team at the University of Central Florida (UCF) has put forward a design that ticks these two boxes, by using seawater in place of flammable and toxic electrolytes, and a new anode to improve its durability.

Inside a battery is an electrolyte solution that carries the electrical charge between the two electrodes, the cathode and anode. Contained within this solution are solvents that are flammable, bringing the risk of fire, and also toxic, bringing the risk of environmental damage when the batteries are depleted and discarded.

A safer and greener alternative would be to use seawater as the electrolyte solution instead, and this is a technology that has seen some exciting advances in recent years. A team from the US Army Research Laboratory, for example, has been working on batteries with saltwater-based electrolytes for a number of years, and has been gradually improving their voltage to the point where they could power household appliances.

The UCF team has been pursuing a similar objective with what’s known as a water-based zinc battery. Where these devices have run into trouble, however, is the growth of zinc on the battery’s anode during operation, which negatively impacts on its durability and overall lifespan.

By using an anode coated in a zinc-manganese nano-alloy instead, the scientists believe they have found a way around this problem. This design proved stable across 1,000 hours of charging and discharging cycles under a high current, showing no signs of degradation throughout.

“We developed a durable and robust 3D electrode that can be used for seawater batteries under extreme conditions,” says study author Yang Yang. “We’ve worked on aqueous batteries and the use of seawater resources for many years, so we have expertise in the field and know where it should go.”

Yang sees possibilities in using this battery design to power underwater vehicles, but also believes that with further development the zinc-manganese alloy could also prove useful in non-water-based batteries.

The research was published in the journal Nature Communications.

Source: University of Central Florida

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