Engineers at UW-Madison have developed a revolutionary additive that significantly improves bromide aqueous flow batteries, offering a safer, cheaper alternative for green energy storage.
Engineers from the University of Wisconsin-Madison have made a significant breakthrough that could revolutionize low-cost renewable energy storage. They’ve developed a water-soluble chemical additive that dramatically enhances the performance of bromide aqueous flow batteries, a promising alternative to traditional lithium-ion batteries.
“Bromide-based aqueous flow batteries are a promising solution, but there are many messy electrochemical problems with them. That’s why there’s no real successful bromide-based products today,” Patrick Sullivan, who holds a doctoral degree in chemistry from UW-Madison, said in a news release. “Yet, our one additive can solve so many different problems.”
Sullivan developed the additive alongside Gyohun Choi, a doctoral student, and Dawei Feng, the Y. Austin Chang Assistant Professor in materials science and engineering at UW-Madison.
The study has been published in the journal Nature.
The Challenge With Current Solutions
Lithium-ion batteries, currently used for grid storage, pose several challenges including safety risks, such as fires and explosions, and complexities in the international supply chain.
In contrast, aqueous flow batteries, which use ions dissolved in water, offer a safer, scalable and more sustainable alternative. However, many aqueous flow batteries currently rely on expensive vanadium ions.
Bromide ions, an economical and abundant alternative, have the potential to overcome the cost barriers, but they come with their own set of issues. Bromide ions can pass through the batteries’ separating membranes, forming messy oils and toxic gases, thus reducing efficiency and reliability.
How the Additive Works
The researchers focused on creating an additive that addresses these persistent problems. After engineering over 500 candidate molecules, they synthesized and tested 13, ultimately identifying an effective “soft-hard zwitterionic trapper.”
This multi-functional additive encapsulates the bromide ions, preventing them from crossing the membrane and stabilizing them in the water electrolyte, thereby eliminating the formation of toxic bromine gas.
“Our devices with the additive functioned without decay for almost two months compared to ones without it, which typically fail within a day,” Feng said in the news release. “This is important because for green energy storage, you want to use it for 10 or 20 years.”
Looking Ahead
The research team plans to continue improving the additive. Choi will delve deeper into the fundamental science behind such additives for both bromide and iodide flow batteries.
Meanwhile, Sullivan, who is now the CEO of Flux XII — a renewable energy spinoff he co-founded with Feng — will further explore the commercial potential of the additive.
Impressively, the additive has already been produced successfully on an industrial scale.
Context and Impact
The implications of this development are vast. If successful, this could dramatically lower the cost of renewable energy storage solutions, making green energy more accessible and reliable.
As solar and wind power continue to gain traction, the need for efficient and affordable energy storage becomes increasingly critical. This breakthrough brings us a step closer to a future where renewable energy can be stored safely and cost-effectively, addressing one of the major hurdles in the transition to green energy.