Organic molecule stores renewable energy with record stability, paving the way for better flow batteries - Energy & Green Tech

Credit: University of Montreal

The main advantage of AzoBiPy is that it can exchange two electrons rather than just one. This means each molecule can store twice as much energy as a single-electron molecule, doubling the system's capacity.

"But the biggest challenge with these organic molecules is stability," said Lebel. "It must be possible for the charge-discharge cycle to run for a long time without the molecule breaking down."

This is where AzoBiPy shines. The team tested a flow battery based on this molecule by operating it for 70 consecutive days, completing 192 full charge-discharge cycles. At the end of the trial, the molecule retained nearly 99% of its initial capacity—a performance the researchers describe as exceptional for an organic molecule.

From laboratory to application

In a festive demonstration at the Department of Chemistry's holiday party in December 2024, the prototype flow battery powered a set of Christmas tree lights for eight hours with tanks containing only about two tablespoons of aqueous solution each.

This demonstration also highlighted another major advantage of the system: It is water-based and therefore non-flammable, unlike lithium-ion batteries, which present a fire risk. "This feature is especially important for large-scale, stationary energy storage facilities," said Rochefort.

Flow batteries powered by molecules such as AzoBiPy could be used to store electricity generated by solar or wind farms. Long-term storage of intermittently generated electricity would make it possible to use it at a later date to meet peak demand.

There could also be residential applications. "It may be possible to develop smaller-scale systems with greener, safer batteries for home use," Lebel suggested.

The research team is drafting a patent application and is already working on the next stages. "We're preparing a scientific article that describes a family of molecules with properties similar to AzoBiPy," said Lebel. "An entire class of compounds with potential for renewable energy storage is opening up to exploration. We expect this technology to be in wider use within 10 to 15 years." 

Provided by University of Montreal 

by Martin LaSalle, University of Montreal

edited by Lisa Lock, reviewed by Robert Egan 

Source: Organic molecule stores renewable energy with record stability, paving the way for better flow batteries