Researchers from Harvard have developed a new flow battery that can last for more than 10 years and is made of non-toxic organic molecules that are dissolved in neutral pH water.

Flow Batteries

Flow batteries store energy in liquid solutions housed in external tanks. Bigger tanks are capable of storing more energy.

Scientists have been promoting the concept of flow battery because it has the advantage of a long cycle life, flexible layout, quick response times, and no harmful emissions.

Limitations Of Currently Available Batteries

Currently available batteries are are hampered by their limited capacity and life span. A lithium-ion pack, for instance, could become useless with just a few years of heavy use, which could be a problem for devices that depend on these batteries for power. The problem is worse for energy storage systems that require long-term use. The new battery could offer a solution to these challenges.

Loses Only 1 Percent Of Capacity For Every 1,000 Cycles

Researchers developed the battery by modifying the molecules that are used in positive and negative electrolyte solutions so they become stable, resistant to degradation, and water-soluble. When these are dissolved in neutral pH water, the resulting solution loses only 1 percent of its capacity every 1,000 cycles, which means that it would take several years before a slight dropoff in performance becomes apparent.

Battery Uses Non-Toxic Materials

Because the battery is not corrosive or toxic, there is also no worry about the potential dangers posed by battery leaks. Elements found in batteries today can damage the skin and cause health problems with contact. Battery leaks can also damage the home and the environment.

"Because we were able to dissolve the electrolytes in neutral water, this is a long-lasting battery that you could put in your basement," said study researcher Roy Gordon from the Harvard John A. Paulson School of Engineering and Applied Sciences. "If it spilled on the floor, it wouldn't eat the concrete and since the medium is noncorrosive, you can use cheaper materials to build the components of the batteries, like the tanks and pumps."

Reduced Production Costs

Besides being long-lasting and nature-friendly, the battery is developed using a technique that holds potential in significantly reducing production costs. The materials used by the researchers are less expensive compared with the polymers often used in flow batteries. These do not also require exotic pumps and tanks to withstand the harsher chemicals.

The researchers have already started working with several companies in a bid to scale up the technology but the method remains limited to lab test stage. It could take time before an industrial solution can be reached to make mass production of these batteries possible. Nonetheless, the new flow battery offers a promising storage solution for renewable and intermittent energy.

"This approach may provide the decadal lifetimes that enable organic-organometallic redox flow batteries to be cost-effective for grid-scale electricity storage, thereby enabling massive penetration of intermittent renewable electricity," the researchers wrote in their study, which was published in ACS Energy Letters on Feb. 7.

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