Scientists at the University at Buffalo have identified a fluorescent dye called BODIPY as a suitable material for stocking energy in rechargeable, liquid-based batteries that could one day power small and large scale devices, including cars and homes.
According to the researchers, a BODIPY-based test battery can operate efficiently and with longevity, running well after researchers drained and recharged it 100 times.
"All alternative energy sources are intermittent, so we need batteries that can store enough energy to power the average house," explained lead researcher Timothy Cook.
Redox flow batteries consist of two tanks of fluids separated by various barriers.
When the battery is being used, electrons are harvested from one tank and moved to the other, generating an electric current. To recharge the battery, solar, wind or other energy sources would be used to force the electrons back into the original tank.
Redox flow batteries can be enlarged to store more energy – enough to allow a homeowner to power a solar house overnight, for instance, or to enable a utility company to stockpile wind energy for peak usage times.
Also, according to Cook, lithium-ion batteries are risky in that they can catch fire if they break open. If the dye-based batteries ruptured, however, they would simply leak.
"The library of molecules used in redox flow batteries is currently small but is expected to grow significantly in coming years," Cook says. "Our research identifies BODIPY dye as a promising candidate."
The BODIPY compounds display a notable quality: they can give up and receive an electron without degrading. This trait enabled the dye to store electrons and facilitate their transfer between the battery's two ends during repeated cycles of charging and draining.
Based on the experiments, scientists predicted BODIPY batteries could generate 2.3V of electricity.