New Battery Additive Could Make Energy Storage Safer and Cheaper
A new approach to bromide flow batteries resolves efficiency challenges, potentially contributing to sustainable energy practices in laboratories.
Researchers at the University of Wisconsin–Madison have developed a chemical additive that significantly improves the performance of bromide aqueous flow batteries, resolving key issues that have hindered their practicality. Published in Nature, the study introduces a “soft-hard zwitterionic trapper” additive capable of stabilising bromide ions in water-based systems.
Bromide flow batteries are a safer and potentially more sustainable alternative to lithium-ion systems for energy storage. However, issues such as membrane inefficiency, phase instability, and toxic gas formation have limited their adoption. “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,” said Patrick Sullivan, co-developer of the additive and co-founder of Flux XII.
The research team designed and tested 13 organic molecules to encapsulate bromide ions. Their chosen additive prevents the ions from leaking through membranes or forming insoluble precipitates and toxic bromine gas. Dr Dawei Feng, assistant professor of materials science and engineering, noted the significance of the discovery: “Our devices with the additive functioned without decay for almost two months compared to ones without it, which typically fail within a day.”
Technological Advancements in Flow Battery Chemistry
The innovation highlights the potential of molecular design in improving flow battery systems. Unlike lithium-ion batteries, which pose safety risks and rely on limited resources, aqueous flow batteries use abundant materials like bromide, making them more scalable and sustainable.
Flow batteries operate by circulating liquid electrolytes across electrodes separated by a membrane. The new additive enhances this process by stabilising bromide ions, preventing their migration through the membrane and addressing phase instability issues. These improvements directly impact the efficiency and durability of the batteries, which are critical for long-term energy storage.
This research represents progress in addressing key technical barriers to bromide flow battery adoption. While the team’s focus remains on optimising the chemistry, their findings also pave the way for industrial applications. Flux XII has already demonstrated that the additive can be produced at scale, an important step towards commercial viability.
Potential Implications for Laboratory Sustainability
Although the primary focus of this research is improving flow battery efficiency, its implications for laboratory sustainability are notable. Laboratories are often energy-intensive, requiring reliable storage solutions for intermittent renewable sources like solar and wind. Aqueous flow batteries equipped with this additive could offer safer, more stable, and potentially cost-effective alternatives to existing systems.
The reduced production of toxic by-products, combined with the potential for longer operational lifespans, could make these batteries a suitable option for laboratories seeking sustainable power solutions. However, the full adoption of this technology in such contexts will depend on further refinement and practical integration.
Looking ahead, co-developer Gyohun Choi plans to explore the fundamental science of additives for bromide and iodide flow batteries, while Sullivan and Flux XII focus on assessing the additive’s commercial potential. As these advancements continue, their influence on energy storage systems—both within and beyond laboratory settings—will become clearer.
