Researchers have their attention directed on the safe storage and discharge of large amounts of energy, as renewable power becoming more popular these days. Expensive lithium-ion batteries are not doing well, so they are turning to flow batteries, which seem more promising. Now, a major breakthrough on such batteries at the Harvard University has made the future even brighter.
A flow battery was introduced by the same university last year, showing it to store energy in vats of inexpensive chemicals. Its design has been improved using non-toxic chemicals and has been made scalable and cheap. As explained by professor of materials and energy technologies at the Harvard School of Engineering and Applied Sciences, Michael Aziz, “Think about running your home on the electricity from your rooftop solar panels that you get during the day. You need to be able to run that battery for hours before it is drained. Traditional solid electrode batteries are drained within an hour.” This means that you could stack up a lot of batteries to get more energy, but this can quickly become really expensive that it can be difficult to afford.
On the other hand, flow batteries are different by separating the energy storage aspect from the electrode interface that charges the battery or releases the energy. However, these batteries have been expensive due to the precious metals, such as vanadium, they use in the negative solution. But through extensive research, scientists at Harvard found out how to replace vanadium with quinone, but there were still problems with the chemicals, particularly bromine, to be used on the positive side, particularly about toxicity and corrosion.
The issue was resolved by replacing bromine with a much safer chemical called ferrocyanide, which is actually a food additive. According to the Cabot Professor of Chemistry and Materials Science at Harvard, Roy Gordon, this compound is not poisonous. This was supported by Aziz, stating, “Ferrocyanide is a positive electrode material that’s safe and stable in an alkaline solution. [That meant] we had to develop a quinone that was highly soluble and stable in an alkaline solution to match up against ferrocyanide, to make the new battery that we just reported this year.”
With regards to the problem with the ferrocyanide preferring and alkaline over an acidic environment, Mike Marshak, who was working on the project, discovered that quinones could actually be dissolved in an alkaline solution, opening up the world of alkaline electrochemistry.
Now, professors Gordon and Aziz envisioned the technology their team unveiled will be safe, cheap and versatile enough to power up a single-family home or an entire community.
Aziz estimated that it would take about 3 years to develop commercial systems ready for scaling these batteries. As for Gordon, he is seeing the flow battery and its new system to be one of the most exciting discoveries to date, saying, “If our future is going to be sustainable, as a civilization, we need to be able to solve these [energy] problems.” Aziz also expressed his thoughts on this matter, stating, “This is certainly the most exciting thing I’ve worked on because the implications are so global. The greatest challenge facing humanity this century —I’m convinced — is finding the energy to power a civilization of 10 billion people without unacceptable consequences to the environment. Renewable energy is front and center in that challenge, and this could really be a very significant enabler of renewable energy.”