In the research published in the journal ChemSusChem, researchers have identified a glow-in-the-dark fluorescent dye which may be an ideal material for stockpiling energy in rechargeable, liquid-based batteries that could one day power car and homes.
The chemical is boron-dipyrromethene, better known as BODIPY, is consists of a set of carbon rings linked to a boron atom and two fluorine atoms. It shines brightly in the dark under ‘black’ light. Chemistry researchers use it as a maker to see reactions or identify where biological system take up other substances such as Cadmium.
The traits that facilitate energy storage are less visible. According to researchers from University at Buffalo (UB) in the United States, the dye has unusual chemical properties that enable it to excel at two key tasks, storing electrons and participating in electron transfer. Batteries must perform these functions to save and deliver energy, and BODIPY is very good at them.
The researchers found that small amounts of the dye added to a solution of acetonitrile could make a battery that can be charged and recharged 100 times without losing its ability to store energy efficiently.
Lead researcher Timothy Cook, an assistant professor of chemistry at the University at Buffalo, said, “As the world becomes more reliant on alternative energy sources, one of the huge questions we have is, ‘How do we store energy?’ What happens when the sun goes down at night, or when the wind stops? All these energy sources are intermittent, so we need batteries that can store enough energy to power the average house.”
BODIPY is a promising material for a liquid-based material called a ‘redox flow battery’. These fluid-filled power cells present several advantages over those made from conventional materials.
The redox battery may be a safer option than lithium-ion batteries, which sometimes catch fire. This happens because the lithium in them is ionized, meaning it has given up an electron. That makes the element very reactive with the oxygen in water, including the moisture in the air, forming lithium oxide and releasing hydrogen. The dye-based batteries would not have this problem. If they ruptured, they would simply leak.
The liquid in a redox battery is instead stored in tanks, and can be recycled through the volume of the battery. Eventually, even redox batteries degrade, but a fresh liquid supply can allow them to be used again. Its effectiveness depends on the chemical properties of the fluids in each tank.
Cook said the technology was originally developed at NASA for space probes, but the agency eventually found better battery solutions for spacecraft. Redox flow batteries can be easily enlarged to store more energy enough to allow a homemaker to power a solar house overnight, for instance, or to enable a utility company to stockpile wind energy for peak usage times. This matters because scaling up has been a challenge for many other proposed battery technologies.
To recharge the battery, you would use a solar, wind or other energy source to force the electrons back into the original tank, where they would be available to do their job again.
Based on the experiments, scientists also predict that BODIPY batteries would be powerful enough to be useful to society, generating an estimated 2.3 volts of electricity.