A battery made from rhubarb: sustainable and cheap
The next step for renewable energy is to figure out how to store all the power we create. Harvard researchers have used a molecule nearly identical to one in rhubarb to make a battery that can store more energy—for less money—than solid-state and traditional flow batteries. “We have something that could change the way we deal with electricity,” says Harvard engineer Michael Aziz. By 2017, they hope to release a commercial version big enough to hold a day’s worth of energy from a typical three-kilowatt home rooftop solar array.
Many existing flow batteries use expensive rare earth metals like vanadium. This new battery is modeled on photosynthesis and uses quinones, small molecules that store energy in plants and animals. They cause a beautiful color change from yellow to red-brown during charging, and are cheap and naturally abundant. Aziz hopes one day to store electricity from solar farms—without depending on scarce, costly materials.
Batterie al rabarbaro, verdi e low cost (fonte: Harvard University/Green Energy Storage)
These rhubarb-based batteries would work differently from normal batteries such as the AAA batteries we are all familiar with. In so-called flow batteries, energy is stored is separate tanks filled with an electrolyte-rich liquid solution in which molecules capture the electric charge. In contrast to lithium batteries, flow batteries have the advantage of being able to increase their storage capacity simply by boosting the size of the chemical tanks.
Quinone is a substance normally found in plants and animals that can change states numerous times without being degraded; the anthraquinone molecules found in rhubarb are unknown to most people but in fact are used as an oxidizing agent in the manufacturing of paper, petrochemicals and pasta. That means it can already be found in large volumes at relatively low cost.
These new batteries could be ready for sale from 2017 thanks to Green Energy Storage, an Italian company that has reached a deal with Harvard for an exclusive license in Europe. The batteries will initially be targeted at household applications, allowing consumers to spend only a third of what they do today for regular battery systems. In future, the company wants to make batteries that can store much larger amounts of energy, for industrial use.
Source: Popular Science
Date: October 2015
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